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  • 1985-1989
  • 1970-1974  (10,570)
  • 1971  (5,533)
  • 1970  (5,037)
  • Chemistry  (10,453)
  • Inorganic Chemistry  (1,597)
  • Bone  (62)
  • Electron microscopy  (60)
Material
Years
  • 1985-1989
  • 1970-1974  (10,570)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 76-80 
    ISSN: 1432-0827
    Keywords: Pickets ; Bone ; Osteocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des couronnes périostéocytaires hypominéralisées au niveau de biopsies osseuses pratiquées, chez des patients, atteints de rachitisme résistant à la vitamine D, s'observent plus fréquemment autour d'ostéocytes jeunes que d'ostéocytes âgés. Ce fait indique qu'à un moment donné, cette hyperminéralisation périostéocytaire peut disparaitre et que, par consequence, il existe un intervalle de temps dans la minéralisation de la matrice organique périostéocytaire.
    Abstract: Zusammenfassung Höfe von schwach mineralisierten Periosteocyten werden in Knochenbiopsien von Patienten mit Vitamin D-resistenter Rachitis häufiger rings um die jungen als um die alten Osteocyten beobachtet. Es scheint somit, daß nach einiger Zeit die unvollständige Mineralisation, die auf Grund der Höfe angenommen werden werden kann, einen “Heilungsprozeß” erfährt und daß deshalb eine verzögerte Mineralisation der perlicunären organischen Matrix erfolgt.
    Notes: Abstract Udermineralized periosteocyte haloes in bone biopsies from patients with vtamin D-resistant rickets occur more frequently around young than around old osteocytes, indicating that in time the incomplete mineralization suggested by the haloes, undergoes a “healing” process and therefore there is a delay in the mineralization of the perilacunar organic matrix.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 134 (1971), S. 13-48 
    ISSN: 1432-0568
    Keywords: Bone ; density ; Bone ; stresses ; Equidensities ; Femur ; photoelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Röntgendichte des Knochens wird mit einer neuen fotografischen Mothode gemessen. Dabei wird jeder Dichteumfang als „Äquidensite” abgebildet. In den Summationsbildern ist die Dichteverteilung direkt abzulesen und anhand einer mitabgebildeten Aluminiumtreppe als Vergleichskörper zu quantifizieren. Untersucht werden dreicoxale Femurenden mit Normalmaßen, eine Coxa valga, eine Coxa vara und eine Coxa vara nach medialem Schenkelhalsbruch. Die Meßgenauigkeit wird mit densitometrischen Dichtebestimmungen von Knief (1967 a, b) verglichen. 1. Die fotografisch gemessene Dichteverteilung entspricht der densitometrisch gemessenen. 2. Die Meßgenauigkeit ist etwas geringer als bei der üblichen Densitometrie. 3. Die Dichteverteilung ist, durch Raster oder Farben markeirt, direkt abzulesen. 4. Die elektive Darstellung einer bestimmten Dichtestufe ist direkt möglich. Die Materialverteilung wird mit der Beanspruchungsverteilung im Isochromatenbild von Pauwels (1955) und Knief (1967b) verglichen. Dazu werden Röntgenbilder von Frontalschnitten eines normalen coxalen Femurendes und der Coxa valga untersucht. 1. Die Materialverteilung stimmt bei beiden Untersuchungsobjekten mit der Beansupruchungsverteilung im Modellversuch sehr gut überein. 2. Lediglich im Kopfbereich treten relativ zu geringe Isochromatenordnungen auf. Anschließend wird erneut die Frage diskutiert, ob der Knochen ein Körper gleicher Festigkeit ist. Wegen der guten Übereinstimmung von Materialverteilung und Beanspruchungsverteilung und aufgrund theoretischer Überlegungen über die Änderung der Beanspruchungsverteilung bei älteren Individuen muß angenommen werden, daß die lokale Beanspruchungsgröße und die vorhandene Materialmenge einander entsprechen, daß es sich somit beim menschlichen coxalen Femurende tatsächlich um einen „Körper gleicher Festigkeit” handelt.
    Notes: Summary The density in X-ray pictures of bone is determined by a new photographical method. The film produces directly “equidensities” of each density range. The pictures of the summarized equidensities show directly the density distribution which can be quantified by comparison with an aluminium staircaise, taken on the same film. Three coxal femoral ends of normal size, one coxa valga, one coxa vara, and a coxa vara after medial fracture of the collum femoris are investigated. The exactness of the measurement is compared with X-ray densitometry by Knief (1967a, b). 1) The photographically determined density-distribution is equivalent to the X-ray densitometry. 2) The exactness of the measurement is slightly minor than in densitometry. 3) The distribution of density, marked by cross-hatching or colours, is directly shown. 4) The electiv representation of a desired range of density is directly possible. The distribution of bone minerals is compared with the distribution of local stress in photoelastical experiments of Pauwels (1955) an Knief (1967b). For that purpose the density distribution of a frontal slice of a normal coxal femural end and a coxa valga is examined in X-ray pictures. 1. The distribution of bone minerals correspond to the local stress in photoelastic experiments in both objects nearly perfect. 2. Only in the caput femoris of the plastic models the number of isochromes was relatively too small. The question, whether bone is a “body of uniform strength” is newly discussed. The good correspondance between mineral distribution and local stress in plastic models and theoretical refletions concerning the alteration of strain distribution in older individuals make it highly probable that local stress and local quantity of material are corresponding and that human coxal femoral end is a “body of uniform strength” indeed.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 23-30 
    ISSN: 1432-0827
    Keywords: Ageing ; Cancellous ; Cortical ; Bone ; Osteoporosin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La masse de l'os spongieux de 129 cadavres des deux sexes a été déterminée. Dans 77 cas, la masse de l'os cortical est également mesurée. La masse de l'os spongieux d'os de la crête iliaque est établie à l'aide d'une méthode physique, basée sur le principe d'Archimède. La masse de l'os cortical est mesurée au niveau du second métacarpe de la main droite à l'aide d'une méthode graphimétrique aux rayons X. La masse de l'os spongieux et cortical décroit significativement avec l'âge chez la femme, mais non chez l'homme. Une corrélation significative a pu être établie chez la femme entre la masse de l'os cortical et spongieux.
    Abstract: Zusammenfassung Die trabeculäre Knochenmasse von 129 Leichen beiden Geschlechts wurde gemessen. In 77 Fällen wurde auch die corticale Knochenmasse gemessen. Die trabeculäre Knochenmasse von Beckenkammproben wurde mit einer physikalischen Methode bestimmt, welche auf dem Prinzip des Archimedes basiert. Die corticale Knochenmasse wurde am zweiten Metacarpus der rechten Hand mittels einer graphimetrischen Röntgenmethode gemessen. Die trabeculäre und die corticale Knochenmasse nahm bei Frauen, aber nicht bei Männern, mit zunehmendem Alter stark ab. Bei Frauen wurde eine signifikante Korrelation zwischen corticaler und trabeculärer Knochenmasse festgestellt.
    Notes: Abstract Trabecular bone mass was measured in the iliac crest of 129 cadavera of both sexes with a physical method based on the principle of Archimedes. Cortical bone mass was measured at the second metacarpal of the right hand with a graphimetric X-ray method in 77 cases. Trabecular and cortical bone mass decreased significantly with age in women but not in men. A significant correlation between cortical and trabecular bone mass was established in women.
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  • 4
    ISSN: 1432-0827
    Keywords: Electron spin resonance ; Resorption ; Irradiation ; Bone ; Graft
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La technique de la résonance aux électrons (ESR) a été utilisée pour étudier la résorption et la substitution progressive de greffons osseux stérilisés par irradiation (à une dose de 3.3 Mrads) chez le lapin et le chien. Le signal stable d'ESR, émis par la perte de substance structurale induite par le rayonnement au niveau du minéral osseux, est utilisé comme marqueur biologique. La concentration de résonance et le nombre total des centres paramagnétiques sont mesurés avant et après greffe. Ue décroissance progressive de la concentration de résonance et du nombre total des centres paramagnétiques est observée après des intervalles de temps variables, faisant suite à l'implantation. En considérant la stabilité inhabituelle et le manque de réactivité chimique des centres paramagnétiques intéressés, il apparait que la décroissance des intensités du signal ESR observé indique une résorption et une substitution progressive. Cette méthode parait intéressante pour des recherches sur les tissues calcifiés.
    Abstract: Zusammenfassung Zur Erforschung der Resorption und der schleichenden Substitution von radiosterilisierten (Dosis: 3,3 Mrad) Knochentransplantaten bei Kaninchen und Hunden wurde die Technik der elektronischen Drehresonanz (ESR) angewendet. Als biologische Markierung diente das stabile ESR-Signal, welches aufgrund des bestrahlungsbedingten Strukturdefektes im Knochenmineral entsteht. Die Drehkonzentration und die Gesamtzahl der paramagnetischen Zentren wurden vor und nach dem Transplantieren gemessen. In verschiedenen Zeitintervallen konnte nach der Implantierung eine allmähliche Abnahme der Drehkonzentration sowie der Gesamtzahl der paramagnetischen Zentren beobachtet werden. Aus der ungewöhnlichen Stabilität und der fehlenden chemischen Reaktionsfähigkeit der beteiligten paramagnetischen Zentren wird geschlossen, daß die beobachtete abnehmende ESR-Signalintensität ei Zeichen für die zunehmende Resorption und Substitution ist. Es scheint, daß mit der besprochenen Technik eine brauchbare Methode zur Erforschung von mineralisiertem Gewebe zur Verfügung steht.
    Notes: Abstract The electron spin resonance (ESR) technique has been applied to the investigation of the resorption and creeping substitution of radiosterilized (3.3 Mrads dose) bone grafts in rabbits and dogs. The stable ESR signal arising from the radiation-induced structural defect in bone mineral was used as a biological label. the spin concentration and the total number of paramagnetic centres were measured before and after grafting. The gradual decrement of spin concentration as well as that of total number of paramagnetic centres were observed at varioust ime intervals after implantation. On the basis of the unusual stability and lack of chemical reaction of the paramagnetic centres involved, it is concluded that the decrease of the observed ESR signal intensities indicates progressive resorption and substitution. it seems that the proposed method can be useful for research o mineralized tissues.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 67-75 
    ISSN: 1432-0827
    Keywords: Bone ; Resorption ; Ablumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Certains sérums albumines provoquent une résorption d'os vivatin vitro. Cet effet de l'albumine est en rapport avec la concentration du produit. L'albumine dialysée et l'albumine chauffée à 55° conserve totalement son activité de résorption osseuse: l'albumine dénaturée par la chaleur est inactive. L'action de l'albumine est inhibée par l'élévation du pH. Il n'y a pas de rapport entre l'activité de résorption osseuse et la propriété de combinaison des albumines aux ions calciques ou leur propriété de libérer des ions d'hydrogène. La thyrocalcitonine, le glucago, les glucocorticoides et l'actinomycine D Inhibent la résorption osseuse induite par l'albumine.
    Abstract: Zusammenfassung Einige Serunmalbumine verursachen die Resorption von lebenden Knochenin vitro. Diese Wirkung des Albumins ist konzentrationsabhängig. Dialysiertes und auf 55° erhitztes Albumin behalten ihre volle knochenresorbierende Aktivität; hitzedenaturiertes Albumin ist inaktiv. Der Albumineffekt wird durch erhöhtes pH gehemmt. es besteht keine Korrelation zwischen der knochenauflösenden Aktivität und der Fähgkeit des Albumins, Ca-lonen zu binden oder H-Ionen abzugeben. Thyrocalcitoni, Glucagon, Glucocorticoide und Antinomycin D wirken als Antagonisten der durch Albumin verursachten Kochenresorption.
    Notes: Abstract Some serum albumins cause resorption of living bonein vitro. This effect of albumin is concentration-dependent. Dialyzed albumin and albumin heated at 55° retain full bone resorbing activity; heat denatured albumin is inactive. The albumin effect is inhibited by elevated pH. No correlation exists between bone resorbing activity and the capacity of albumins to bind calcium ions or to donate hydrogen ions. Thyrocalcitonin, glucagon, glucocorticoids and actinomycin D antagonize albumin-induced bone resorption.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 93-102 
    ISSN: 1432-0827
    Keywords: Strontium ; Vitamin D3 ; Calcium ; Absorption ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des poulets, âgés de 2 semaines, après a voir été soumis pendant 7 jours à un régime pauvre en calcium (0,1%), riche en vitamine D3, à contenu stable en strontium à une concentration équimolaire à 1,2% de calcium, reçoivent à nouveau une alimentation normale. Les graves lésions osseuses, provoquées par le régime au strontium, disparaissent au bout de 3 jours d'alimentation normale. L'inhibition du mécanisme d'absorption intestinal du calcium et l'action inhibitrice initiale du strontium alimentaire sont totalement abolies. Cependant les troubles de la minéralisation ne disparaissent que partiellement.
    Abstract: Zusammenfassung Nachdem normale, 2-wöchige Kücken während 7 Tagen eine calciumarme (0,1%), Vitamin D3-reiche und 2,62% kaltes Strontium (molaraequivalent mit 1,2% Calcium) enthaltende Nahrung erhielten, wurden sie wieder auf normales Futter gesetzt. Die schwere Knochenläsion, die sich durch die Strontiumfütterung entwickelt hatte, bildete sich zu einem großen Teil schon nach 3 Tagen normaler Nahrung wieder zurück. Die Hemmung der Calciumabsorption im Darm, die anfängliche inhibierende Wirkung des Strontiums aus der Nahrung, wurde vollständig aufgehoben; dagegen besserte sich der Mineralisationsdefekt nur teilweise.
    Notes: Abstract Two week old normal chicks, after having been fed a low-calcium (0.1%), vitamin D3-replete diet containing stable strontium at a level equimolar to 1.2% calcium for 7 days, were transferred back to a normal diet. The severe bone lesion that developed with strontium feeding was, to a large extent, reversed after only 3 days on the normal diet. The inhibition of the intestinal calcium absorptive mechanism, the initial inhibitory action of dietary strontium, was fully reversed whereas the recovery from the defect in mineralization was only partially reversed.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 150-162 
    ISSN: 1432-0827
    Keywords: Uranium ; Bone ; Distribution ; Fission ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une concentration moyenne de 2.4×10−8 g U/g de cendre a été obtenue à partir de l'os humain normal. La microdistribution de l'uranium dans l'os indique que cet élément est surtout limité à surface de l'endoste et, en particulier, aux surfaces de l'os lamellaire et aux parois des canaux de Havers, ouverts dans l'os corticol. Cette répartition suggère que l'uranium se présente sous une forme chimique impropre à son incorporation dans l'apatite osseux: il ne semble donc pas exister une distribution diffuse significative de l'uranium dans l'os.
    Abstract: Zusammenfassung Eine mittlere Konzentration von 2,4×10−8 g Uran/g Asche wurde in normalen menschlichen Knochen gefunden. Die Feinverteilung von Uran im Knochen zeigt, daß dieses Element hauptsächlich an der endostalen Oberfläche vorkommt, insbesondere an der Oberfläche des trabeculären Knochens und an den Wänden der offenen Haversschen Kanäle im kortikalen Knochen. Diese Verteilung läßt vermuten, daß Uran in einer chemischen Form vorliegt, welche sich für den Einbau in das Knochenapatit nicht eignet. Daraus folgt, daß keine signifikante diffuse Verteilung des Urans innerhalb des Knochens vorliegt.
    Notes: Abstract A mean concentration of 2.4×10−8 g U/g ash has been obtained for normal human bone The microdistribution of uranium in bone indicates that this element is mainly restricted to endosteal surfaces; in particular the surfaces of trabecular bone and the walls of open Haversian canals in cortical bone. This distribution suggests that uranium is present in a chemical form that is not acceptable for incorporation into bone apatite and consequently there does not appear to be a significant diffuse distribution of uranium throughout bone.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 139-149 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Estrogen ; Ultrastructure ; Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Dix rats Holtzman mâles et sevrés sont sacrifiés injection intrapéritonéale d'oestradiol (Progynon, Schering) aqueux, à des doses quotiediennes de 1 μ g. par g de poids. Des témoins, ayant reçu une dose équivalente de liquide de dilution, sont sacrifiés à des intervalles de 1 heure à 6 jours, identiques aux temps de sacrifice des animaux injectés. Les cartilages épiphysaires supérieurs des tibias tibias (ECP) étudiés en microscopie électronique, montrent, dès trois heures après l'ionjection, une augmentation nette de 'activié sécrétoire, caractérisée, au niveau de la zone de sécrétion matricielle, par l'abondance dans les citernes golgiennes d'un matériel piqueté, constitué par des complexes protéino-polysaccharidiques. La désintégration de la membrane limitante de vésicules golgiennes individuelles est plus avancée après vingt quatre heures: après trois jours de traitement, seules quelques vésicules restent intactes et des plages d'un matériel initialement intravacuolaire sont visibles dans le cytoplasme. De longs filaments, rappelant les précurseurs ou les fibrilles primaires du collagène, sont visibles dans cette sécrétion. Après six jours, de grandes plages de cettre subestance remplissent les cellules de la couche pré-hypertrophieque, avec déplacement de l'ergastoplasme en périphérie. Des vacuoles cytoplasques, contenant un matériel semblable à celui qu'on retrouve dans la lacune, et présentant des filament finement moniliformes et disposés en rayons le long de la membrane limitante, sont visibles. Ces observations suggèrent une accélération initiale de l'activité sécrétoire chondrocytaire, suivie par un retard de transfert. La rétention consécutive et la polymérisation intracellulaire de produits précollagéniques accélèrent l'hypertrophie et favorisent ainsi la dégénérescence précoce des chondrocytes. Ces altérations ultrastructurales paraissent être spécifiques aux oestrog`enes.
    Abstract: Zusammenfassung Zehn männliche Hotlzmann-Ratten, die im Entwöhnungsstadium waren, erhielten täglich wässerige Oestradioldosen (Progynon, Schering) von 1 μ/g Körpergewicht i.p. Dann wurden sie gleichzeitig mit Kontrolltieren, welche die gleiche Menge Verdünnungsmittel erhalten hatten, in Intervallen von 1 Std bis zu 6 Tagen getötet. Platten des oberen tibialen Epiphysenknorples (ECP), welche für die Elektronenmikroskopie präpariert wurden, zeigtem, daß schon 3 Std nach der Injektion ein bemerkenswerte Erhöhung der sekretorischen Tätigkeit entsteht. Dies wurde in der Zone der Matrixausscheidung sichtbar, wo sich in den Golgi-Zisternen eine Anhäufung von punktiertem, aus Proteinpolysaccharid-Komplexen bestehendem Material zeigte. Der Zerfall der Membran, welche die einzelnen Golgi-Bläschen umgibt, nahm nach 24 Std zu; nach 3 Tagen Behandlung blieben nur wenige Gefäße intakt, und Ansammlungen von ursprünglich intravacuolörem Material konnten im Grundplasma beobachtet werden. Lange Fasern, welche auf primäre oder Prae-Kollagefibrillen hindeuteten, konnten in diesem Sekret gesehen werden. Nach 6 Tagen wurden die Zellen in der prähypertrophen Zone mit dieser Substanz richtiggehend überschwemmt, und das rauhe endoplasmatische Reticulum wurde anschließend gegen die Zellperipherie verlagert. Die oft beobachteten cytoplasmatischen Vacuolen enthielten ein Material, das dem in den Lacunen vorkommenden ähnlich ist und zeigten auf der ungebrenden Membran feinperlige, radial angeordnete Fasern. Unsere Beobachtungen deuten auf eine anfängliche Beschleuning der chondrocytischen sekretorischen Tätigkeit, mit nachfolgender Transportverlangsamung, hin. Die dadurch entstehende Retention und intrazelluläre Polymerisation von präkollagenen Produkten beschleunigt die Hypertrophie und begünstigt dadurch die frühe Degeneration von Chondrocyten. Diese ultrastrukturellen Veränderungen scheinen oestrogen-spezifisch zu sein.
    Notes: Abstract Ten male weanling Holtzman rats, injected intraperitoneally with aqueous estradiol (Progynon, Schering), in daily doses of 1 μg. per g body weight, were sacrificed, simultaneously with controls receiving an equivalent amount of diluent, at intervals ranging from one hour to six days. Upper tibial epiphyseal cartilage plates (ECP), procesed for electron microscopy, revealed, as early as three hours after injection, appreciable enhancement of secretory activity, evidenced, in the zone of matrix secretion, by the abundance in Golgi cisternae of stippled material representing proteinpolysaccharide complexes. Disintegration of the lining membrane of individual Golgi vesicles was advanced after twenty-four hours; following three days of treatment, few vesicles remained intact, and pools of initially intravacuolar material were observable in the gound plasm. Long filaments, suggestive of primary or precursor collagen fibrils were apparent in this secretion. After six days, virtual lakes of this substance filled cells in the zone of prehypertophy, with consequent displacement of the rough endoplasmic reticulum against the cell periphery. Cytoplasmic vacuoles, containing mateerial similar to that found in the lacunar moat, and displaying finely beaded, radially arrayed filaments on the lining membrane were frequently encountered. Our observations suggest an initial acclleration of chondrocytic secretory activity, with subsequent retardation of transport. The resultant retention and intracellular polymerization of precollagenous products accelerates hypertrophy, thereby promoting early degeneration of chondrocytes. These ultrastructural alterations are apparently estrogen-specific.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 8 (1971), S. 24-35 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Epiphysis ; Calcium ; Phosphorus ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les électrolytes ont été analysés dans le sérum et dans les tissues en voie de minéralisation, à des stades variables de calcification, chez des poulets et des pores normaux et rachitiques. L'humidité, les cendres et les matières organiques et déssèchées ont été analysées. Il apparait que d'autres électrolytes sériques, en plus du Ca, sont modifiés au cours du rachitisme. Le Mg et le P inorganique sont modifiés de façon variable au cours de l'avitaminose D. Des changements plus importants en contenu minéral des tissus sont observés dans les stades précoces de calcification que ceux que l'on a pu constater dans le sérum à des stades similaires, ce qui suggère un effet direct de l'avitaminose sur le tissu en voie de calcification. Quant au contenu du sérum, le dépôt de Ca est plus élevé dans les tissus d'animaux rachitiques par rapport aux témoins. Ceci n'est pourtant pas le cas du Mg ou du P inorganique, indiquant une affinité préférentielle du Ca pour le tissue rachitique. L'analyse gravimétrique de matières organiques et déssèchées des zones épiphysaires montre que les quantités de cartilage hypertrophique et en voie de dévelopment augmentent dans le cas de rachitisme, alors que le cartilage calcifié diminue, confirmant les observations histologiques antérieures. De manière inattendue, la proportion de cartilage au repos augmente au cours du rachitisme.
    Abstract: Zusammenfassung Die Elektrolyte im Serum und in mineralisierenden Geweben wurden zu verschiedenen Zeitpunkten der Verkalkung bei normalen Hühnern und Schweinen und bei solchen mit Vitamin D-Mangel analysiert. Wassergehalt, Asche, trockene und organische Substanz wurden ebenfalls gemessen. Die Ergebnisse zeigten, daß außer Ca auch andere Elektrolyte bei Rachitis verändert wurden. Mg und anorganischer P wurden durch den Vitaminmangel bei den beiden Gattungen verschiedenartig beeinflußt. In den Geweben wurde in den frühen Phasen der Verkalkung eine größere Änderung des Mineral-Spiegels gefunden, als dies zu übereinstimmenden Zeiten im Serum der Fall war, was auf eine direkte Wirkung des Vitaminmangels auf das verkalkende Gewebe schließen läßt. Im Verhältnis zum Serumspiegel wurde Ca in den Geweben der rachitischen Tiere zu einem größeren Grade als normal abgeschieden. Dies war nicht der Fall bei Mg oder anorganischem P, was einen Vorzug für Ca in den rachitischen Geweben anzeigt. Gravimetrische Analysen von organischer und trockener Substanz in epiphysischen Schichten zeigten, daß die Menge des proliferierenden und hypertrophischen Knorpels zunahm und daß verkalkter Knorpel bei Rachitis abnahm, gemäß klassischen histologischen Beobachtungen. achtungen. Ganz unerwartet war bei Rachitis eine verhältnismäßige Zunahme des ruhenden Knorpels festzustellen.
    Notes: Abstract Electrolytes were analyzed in serum, and in mineralizing tissues at varying stages of calcification, in normal and vitamin D-deficient chickens and pigs. Moisture, ash, and organic matter were also measured. Results revealed that in addition to Ca, other serum electrolytes were altered in rickets. Mg and inorganic P were diversely affected by the vitamin deficiency. Larger changes in mineral level were seen in the tissues in the early stages of calcification than were seen at corresponding times in the serum, suggesting a direct effect of the vitamin deficiency on the calcifying tissue itself. Relative to the serum level, Ca was deposited in the tissues of rachitic animals to a greater extent than in normal animals. This was not true for Mg or inorganic P, indicating a preferential affinity for Ca in the rachitic tissue. Gravimetric analyses of organic and dry matter in epiphyseal zones revealed that the amounts of proliferating and hypertrophic cartilage were increased, and calcified cartilage decreased, in rickets, in accord with previous histological observations. Unexpectedly, the proportion of resting cartilage was also increased.
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  • 10
    ISSN: 1432-0827
    Keywords: Morphology ; Glycosaminoglycans ; Cartilage ; Chemistry ; Audioradiography ; Healing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une perte de substance ostéo-cartilagineuse, de taille limitée et identique, est réalisée chez le lapin adulte et la cicatrisation est étudiée histologiquement et par autoradiographie après marquagein vitro au35S-sulfate. Une analyse microchimique est pratiquée pour le contenu et la composition en glycosaminoglycanes. 1. Entre la première semaine et la 4ème et 8ème semaine, un tissu conjonctif non-métachromatique se différencie en un cartilage métachromatique et la quantité de sulfate de chondroitine augmente de façon significative aux dépens des glycoprotéines. 2. Jusqu'à la 4ème semaine, la perte de substance est surtout comblée par de l'os néoformé: après cette période, la région est comblée au delà de la limite de la surface articulaire. 3. Le cartilage hyalin, ressemblant morphologiquement, autoradiographiquement et chimiquement au cartilage articulaire, en ce qui concerne la distribution en glycosaminoglycanes, constitute la surface articulaire de la perte de substance comblée dans un tiers des cas après 8 semaines. Le cartilage hyalin s'observe surtout dans les régions où de l'os néoformé a comblé la cavité médullaire. 4. Dans les deux tiers des cas, après 8 semaines, les surfaces articulaires des zones comblées comportent, non seulement du cartilage, mais aussi du tissu fibreux se formant essentiellement sur les parties latérales et dans les régions, où la cavité médullaire, fliant face, à la surface articulaire, n'a pas été comblée par du tissue osseux. La fraction glycoprotéique augmente par rapport à la fraction chondroitine sulfate. 5. Dans la majorité des cas, après 20 semaines, le cartilage néoformé subit des phénomènes dégénératifs, qui se traduisent par une diminution en chondroitine sulfate.
    Abstract: Zusammenfassung Bei ausgewachsenen Kaninchen wurde ein begrenzter, standardisierter, osteochondraler Defekt hervorgerufen, und das regenerierte Gewebe wurde histologisch und autoradiographisch durch Markierung in vitro mit35S-Sulfat und durch mikrochemische Bestimmung des Gehaltes und der Zusammensetzung der Glykosaminglykane untersucht. Die wichtigsten Befunde waren: 1. Zwischen 1 und 4–8 Wochen veränderte sich nichtmetachromatisches Bindegewebe zu metachromatisch gefärbtem Knorpel, und der Anteil an Chondroitin-Sulfat nahm auf Kosten der Glykoproteine signifikant zu. 2. Bis zu 4 Wochen war der Hauptteil des defekten Gebietes mit neugebildetem Knochen gefüllt; nach dieser Zeit lag dieser Bezirk oberhalb der Verknöcherungsgrenze in Richtung der Gelenkoberfläche. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 4. Nach 8 Wochen bestanden Teile der Gelenkoberfläche des Defektes in zwei Dritteln der Fälle nicht nur aus Knorpel, sondern auch aus fibrösem Gewebe, welches vor allem in den seitlichen Teilen des Defektes und an Stellen vorlag, wo die Markhöhle gegenüber der Gelenkoberfläche nicht mit Knochengewebe verschlossen worden war. Die Glykoproteinfraktion nahm im Vergleich zur Chondroitin-Sulfatfraktion zu. 5. Nach 20 Wochen zeigten sich in den meisten Fällen bei neugebildetem Knorpel degenerative Veränderungen, welche durch eine gewisse Abnahme des Chondroitin-Sulfats wiedergegeben wurden.
    Notes: Abstract A limited, standardized osteochondral defect was created in adult rabbits and the regenerated tissue was examined histologically and autoradiographically after labellingin vitro with35S-sulphate, and microchemically for its content and composition of glycosaminoglycans. The principal findings were: 1. Between 1 week and 4 to 8 weeks, non-metachromatic connective tissue differentiated to metachromatically stained cartilage, and the proportion of the chondroitin sulphate increased significantly at the expense of the glycoproteins. 2. Up to 4 weeks, the major part of the defect area was filled with newly formed bone; after this time, the area lay above the level of the “tidemark”, towards the articular surface. 3. Hyaline cartilage with morphological, autoradiographic and chemical resemblance to the articular cartilage in terms of the distribution of glycosaminoglycans constituted the articular surface of the defect area in one-third of the cases at observation times after 8 weeks. Hyaline cartilage was observed mainly in areas where newly formed bone had closed the medullary cavity. 4. In two-thirds of the cases, after 8 weeks, parts of the articular surface of the defect consisted not only of cartilage but also of fibrous tissue, occurring mainly in the lateral parts of the defect and in areas where the medullary cavity facing the articular surface had not been sealed by bone tissue. The glycoprotein fraction increased relative to the chondroitin sulphate fraction. 5. In most cases after 20 weeks, newly-formed cartilage underwent degenerative changes, which were reflected in some reduction of the chondroitin sulphate.
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  • 11
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    Calcified tissue international 8 (1971), S. 165-171 
    ISSN: 1432-0827
    Keywords: Bone ; Ceramic ; Tetracycline ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un implant céramique non poreux est testé au niveau du fémur de rat en ce qui concerne son adhésivité à l'os. Un certain nombre de techniques morphologiques sont utilisées pour examiner le rapport entre l'implant et l'os néoformé. La microscopie électronique par transmission et la microscopie par fluorescence après marquage à la tétracycline ont donné les meilleurs résultats. Un rapport étroit entre l'os minéralisé et la céramique a été noté en microscopie électronique. Par marquage à la tétracycline, il semble que l'implant puisse stimuler la formation osseuse.
    Abstract: Zusammenfassung Ein unporöses keramisches Implantat in Rattenfemora wurde auf seine Fähigkeit geprüft, sich mit Knochen zu binden. Eine Anzahl morphologischer Techniken wurde verwendet, um die Beziehung zwischen den Oberflächen von Implantat und neuem Knochen zu untersuchen. Transmissions-Elektronenmikroskopie und Fluoreszenzmikroskopie nach Tetracyclinmarkierung waren die erfolgreichsten Techniken. Eine enge Beziehung zwischen mineralisiertem Knochen und dem Keramikimplantat konnte mit der Transmissions-Elektronenmikroskopie nachgewiesen werden. Das Aussehen der Tetracyclinmarkierung im keramischen Implantat deutet darauf hin, daß dieses wahrscheinlich die Fähighkeit hat, Knochenbildung zu erhöhen.
    Notes: Abstract A nonporous ceramic implant in rat femora was evaluated as to its ability to bond to bone. A number of morphologic techniques were utilized to examine the interfacial relationship of the implant to new bone. Transmission electron microscopy and fluorescence microscopy after tetracycline labelling were the most successful techniques. An intimate relationship between mineralized bone and the ceramic was demonstrated by transmission electron microscopy. The appearance of tetracycline labelling at the ceramic interface indicates that the implant may have capacity to enhance bone formation.
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  • 12
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    Calcified tissue international 8 (1971), S. 258-261 
    ISSN: 1432-0827
    Keywords: Transplantation ; Bone ; Induction ; Osteogenesis ; Amniotic cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cellules épithéliales humaines, obtenues par culture de tissu (de lignée “K”), sont njectées dans les muscles de la cuisse et de la paroi abdominale ou dans le tissu sous-cutané de rats conditionnés par la cortisone. Du cartilage et/ou de l'os se forment dans le tissu musculaire, mais non dans le tissu sous-cutané.
    Abstract: Zusammenfassung Zellen aus der Kultur von menschlichem Epithelialgewebe („K”-Stamm) wurden Cortisonvorbehandelten Ratten in die Bein- oder Bauchwandmuskulatur oder subcutan injiziert. Die Bildung von Knorpel und/oder Knochen wurde in diesen zwei Muskelgeweben leicht ausgelöst; dies war jedoch an den subcutan behandelten Stellen nicht der Fall.
    Notes: Abstract Human epithelial tissue culture line cells (“K” line) were injected into the leg or abdominal wall muscle, or subcutaneously, in cortisone-conditioned rats. Cartilage and/or bone was induced readily in either of the muscular sites, but not subcutaneously.
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  • 13
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    Calcified tissue international 8 (1971), S. 276-286 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Differentiation ; Collagen ; β-aminopropionitrile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'injection d'embryons de poulet, incubés pendant neuf jours, avec du β-aminopropionitrile (BAPN), à des doses supérieures à 0,312 mg par embryon, empêche la formation de cartilage, normalement présent au niveau des os de membrane à partir du llème jour de l'inculation. L'hitsogenese de cette inhibition est décrite. BAPN augmente la propertion de collagène et diminue la synthèse des mucopolysaccharides acides, contenant de l'hesoxamine, au niveau des os de membrane. Le rapport entre les chainons tranversaux du collagène, sa solubilité, la synthèse des mucopolysaccharides acides et la stimulation mécanique (le facteur extrinsèque déclenchant la chondrogenèse dans le système) est discuté sous l'angle de la formation cartilagineuse sur les os de membrane, à partir de cellules souches.
    Abstract: Zusammenfassung Wird β-Aminopropionitrol (BAPN) in Dosen von über 0,312 mg/Embryo in 9 Tage inkubierte Hühnerembryonen injiziert, so wird die Bildung des normalerweise vom 11. Inkubationstag an auf dem Deckknochen vorliegenden Knorpels verhindert. Die Histogenese dieser Hemmung wird beschrieben. BAPN erhöhte den Anteil des löslichen Kollagens, ohne die Synthese des Totalkollagens zu verändern; es verminderte die Synthese der hexosaminhaltigen sauren Mucopolysaccharide innerhalb der Deckknochen. Die Diskussion betrifft die Beziehung zwischen der Quervernetzung des Kollagens, der Kollagenlöslichkeit, der Synthese von sauren Mucopolysacchariden und der mechanischen Stimulation (wobei der Extrinsicfaktor die Chondrogenese in diesem System auslöst) bei der Knorpelbildung aus den bipotentialen Keimzellen der Deckknochen.
    Notes: Abstract Injection into chick embryos incubated for nine days, of β-aminopropionitrile (BAPN) at doses above 0.312 mg/embryo prevented the formation of the cartilage normally present on the membrane bones from the eleventh day of incubation onwards. The histogenesis of this inhibition is described. BAPN increased the proportion of soluble collagen without altering total collagen synthesis and decreased the synthesis of hexosamine-containing acid mucopolysaccharides within the membrane bones. The relationship between cross-linking of collagen, collagen solubility, synthesis of acid mucopolysaccharides and mechanical stimulation (the extrinsic factor initiating chondrogenesis in this system) in the formation of cartilage from bipotential germinal cells on the membrane bones is discussed.
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  • 14
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    Calcified tissue international 8 (1971), S. 228-236 
    ISSN: 1432-0827
    Keywords: Skin ; Calcinosis ; Keratin ; Chemistry ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des études histologiques antérieures ont montré que le follicle pileux est particulièrement susceptible de se calcifier, lorsque la peau de rats hypercalcémiques est lésée. Des analyses chimiques et par diffraction aux rayons X du follicule ont confirmé ce résultat. — En se basant sur l'augmentation du calcium et du phosphore, les calcifications débutent dans le tissue folliculaire 6–12 h après une blessure d'intensité moyenne de la peau de rats, ayant reçu du dihydrotachysterol (DHT), et 24–48 h après une blessure similaire chez des rats non injectés. Les diagrammes de diffraction aux rayons X sont diffus. Trois heures après la blessure, on note une augmentation du calcium du tissu folliculaire qui ne semble pas en rapport avec le DHT qui traduit probablement une liaison de calcium plutôt qu'un dépot minéral.
    Abstract: Zusammenfassung Frühere histologische Untersuchungen haben gezeigt, daß der Haarfollikel besonders anfällig für Verkalkungen ist, wenn die Haut von hypercalcämischen Ratten verletzt wird. Dieses Resultat wurde nun durch direkte chemische Bestimmungen und Röntgendiffraktions-analysen von Follikelgewebe bestätigt. Aufgrund der erhöhten Calcium- und Phosphatwerte kann gesagt werden, daß nach einer leichten Quetschung der Haut von Ratten, die mit Dihydrotachysterol (DHT) behandelt wurden, im Haarfollikelgewebe nach 6–12 Std Mineral-ablagerungen stattfanden, wogegen Kontrollratten mit der gleichen leichten Hautverletzung diese Ablagerungen erst nach 24–48 Std zeigten. Röntgendiffraktionsanalysen ergaben ein diffuses Apatit-Muster. Innerhalb 3 Std nach der Verletzung wurde ein Anstieg des Calcium-gehaltes im Follikelgewebe beobachtet, der nicht im Zusammenhang mit der DHT-Behandlung stand, also nicht eine Mineralablagerung, sondern eher eine Bindung von Calcium widerspiegelte.
    Notes: Abstract Previous histological investigations have shown that the hair follicle is particularly susceptible to mineralization when the skin of hypercalcaemic rats is injured. Direct chemical and X-ray diffraction analyses of follicle tissue have now confirmed this finding. As judged by increases in both calcium and phosphorus, mineral deposits began to form in hair follicle tissue 6–12 h after a mild crush injury to the skin of rats dosed with dihydrotachysterol (DHT), and 24–48 h after a similar injury to the skin of non-dosed rats. X-ray diffraction gave a diffuse apatite pattern. Within 3 h of injury there was a rise in the calcium content of follicle tissue which was not related to DHT-dosing and which was probably a reflection of calcium binding rather than mineral deposition.
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  • 15
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    Calcified tissue international 8 (1971), S. 262-264 
    ISSN: 1432-0827
    Keywords: Bone ; Amnion ; Transplantation ; Immunosuppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé En utilisant du sérum antilymphocytaire de souris, utilisé comme immuno-dépresseur à la place d'hormones stéroides, une induction de tissu osseux est obtenue chez la souris chez laquelle des cellules épithéliales souches K xénogéniques sont greffées. L'induction osseuse dans ce système expérimental n'est donc pas liée aux hormones stéroides.
    Abstract: Zusammenfassung Mit dem als Immunosuppressor wirkenden Anti-Mäuse-Lymphocyten-Serum, welches anstelle von Steroidhormonen verwendet wurde, konnte bei Mäusen, die ein Transplantat von K-xenogenen, festgesetzten Epithelzellen erhalten hatten, das Einsetzen von Knochenwachstum hervorgerufen werden. Diese Resultate zeigen, daß in diesem Modell das Einsetzen des Knochenwachstums nicht von Steroidhormonen abhängig ist.
    Notes: Abstract Using Anti Mouse Lymphocytic Serum as an immunosuppressor instead of steroid hormones, bone induction was obtained in mice grafted with K xenogenic-established epithelial cell line. The results suggest that bone induction in this experimental system is not dependent upon steroid hormones.
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  • 16
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    Calcified tissue international 8 (1971), S. 304-319 
    ISSN: 1432-0827
    Keywords: Chemistry ; Calcium ; Phosphate ; Solubility ; Computer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un programme d'ordinateur a été mis au point pour calculer les activités ioniques du calcium et l'orthophosphate dans un grand nombre de solutions. Dans le cas de solutions synthétiques, les calculs sont vérifiés en comparant les valeurs de pH, obtenues par ordinateur, avec celles observées expérimentalement. Des essais de ce type, avec des solutions possèdant des concentrations de calcium et d'orthophosphate trouvées dans les liquides biologiques et à des valeurs de pH variant de 3.00 à 10.00, indiquent que le programme est adapté pour des applications biologiques. Le programme n'est pas effectif pour des solutions, dans les lesquelles l'ion bromure est la source principale de la force ionique, sans doute, par manque d'équation étendue de Debye-Hückel dans ces circonstances. Aucune formation de complexe de phosphate de sodium n'a été notée à des concentrations biologiques normales.
    Abstract: Zusammenfassung Es wurde ein Computer-Programm ausgearbeitet, um die Ionenaktivitäten von Calcium und Orthophosphat in einer breiten Varietät von Lösungen zu berechnen. Die Berechnungen wurden bei synthetischen Lösungen durch Vergleiche zwischen den auf diese Weise errechneten pH-Werten und den experimentell gefundenen kontrolliert. Diese Art Kontrollen mit Calcium-und Orthophosphatkonzentrationen, wie sie in biologischen Flüssigkeiten gefunden werden, und mit pH-Werten zwischen 3,0 und 10,0 wies darauf hin, daß das Programm für biologische Anwendungen geeignet war. Das Programm konnte nicht benützt werden für solche Lösungen, bei welchen hauptsächlich das Bromidion zur Einstellung der Ionenstärke verwendet wurde, vermutlich weil die erweiterte Debye-Hückel-Gleichung unter diesen Umständen nicht anwendbar ist. Die Bildung eines Natriumphosphat-Komplexes unter normalen biologischen Konzentrationen konnte nicht nachgewiesen werden.
    Notes: Abstract A computer program has been designed to calculate the ionic activities of calcium and orthophosphate in a wide variety of solutions. In the case of synthetic solutions the calculations were checked by comparing the computed pH values with those observed experimentally. Tests of this type with solutions having the concentrations of calcium and orthophosphate found in biological fluids and with pH values ranging from pH 3.0–10.0 indicated that the program was suitable for biological applications. The program was not effective for solutions in which the bromide ion was a principal source of ionic strength probably because of the failure of the extended Debye-Hückel equation under those circumstances. No evidence for the formation of any sodium phosphate complex at normal biological concentrations could be found.
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  • 17
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    Calcified tissue international 7 (1971), S. 1-11 
    ISSN: 1432-0827
    Keywords: Bone ; Microradiography ; Diffraction ; X-rays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des microradiographies par projection sont réalisées à des grossissements initiaux différents, à partir de coupes par usure d'os de 100 microns d'épaisseur, après inclusion dans du méthacrylate de polyméthyle. Les microradiographies sont obtenues en utilisant des rayons X, de diverses longueurs d'onde. A certains grossissements radiographiques, les bords des objets étudiés, normalement transparents aux rayons X, deviennent très radio-opaques. La largeur du bord opaque varie avec la longueur d'onde de la radiation et le grossissement radiographique initial, ce dernier agissant au maximum avec un agrandissement initial de deux fois. Il semble donc que l'effet observé en bordure soit provoqué par un phénomène de diffraction de Fresnel du rayonnement X incident. Les incidences de cet effet sur les microradiographies de tissue osseux sont envisagées.
    Abstract: Zusammenfassung Es wurden Projektionsmikroradiogramme bei verschiedenen Anfangsvergrößerungen von in Polymethyl-Methacrylat eingebetteten, 100 μ dicken Knochenschliffen ausgeführt. Die Mikroradiogramme wurden durch Verwendung von Röntgenstrahlen verschiedener Wellenlängen erhalten. Es wurde festgestellt, daß bei bestimmten radiographischen Vergrößerungen die Ränder von Gegenständen, welche normalerweise für Röntgenstrahlen durchlässig sind, stark opak wurden. Es wurde ebenfalls festgestellt, daß die Breite dieses opaken Randes je nach Wellenlänge der aufnehmenden Röntgenstrahlen und je nach Höhe der Anfangsvergrößerung der Aufnahme variierte. Der breiteste Rand wurde bei einer zweifachen Anfangsvergrößerung festgestellt. Die Autoren kommen zum Schluß, daß dieser Randeffekt das Ergebnis einer Fresnel-Diffraktion der eindringenden Röntgenstrahlen ist, welche für die Herstellung von Mikroradiogrammen verwendet werden. Die Bedeutung dieser Beobachtungen für die Einschätzung der Knochenaktivität mittels Mikroradiogrammen wird diskutiert.
    Notes: Abstract Projection microradiographs were made at various initial magnifications of 100 μ-ground sections of bone embedded in polymethyl methacrylate. The microradiographs were produced by using X-rays of different wavelengths. It was found that at certain radiographic magnifications the edges of objects, normally transparent to X-rays, became highly radiopaque. It was also found that the width of this opaque edge varied with the wavelength of the imaging radiation and with the amount of initial radiographic magnification, the latter being greatest at an initial enlargement of two. It is concluded that this edge effect is the result of Fresnel diffraction of the penetrating X-rays, used for the production of microradiographs. The relevance of these observations to the assessment of bone activity from microradiographs is discussed.
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  • 18
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    Calcified tissue international 7 (1971), S. 12-22 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Testosterone ; Ultrastructure ; Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Bien que la clinique et l'expérimentation semblent démontrer que des doses élevées de testostérone provoquent un arrêt prématuré de la croissance, le mécanisme exact et le lieu précis de son action sur l'appareil de croissance des os longs restent indéterminés. Au cours de cette étude, des rats máles de 200 g sont injectés à l'aide de doses supra-physiologiques de testostérone pour observer les effects sub-microscopiques sur les diverses zones du cartilage épiphysaire. Au niveau de la zone de division cellulaire, on note une augmentation des cellules en division. Les cellules, en voie de maturation, présentent plus de produits de sécrétion, à un stade plus précoce de leur cycle d'évolution, et semblent subir une hypertrophie plus rapide. Dans la zone pré-hypertrophique, la matrice intercellulaire présente des foyers de calcification précoce, ainsi que des fibres collagènes plus longues et plus épaisses que chez les témoins. Il apparait que, chez l'animal entier, des doses même élevées de testostérone provoquent initialement une stimulation de la prolifération chondrocytaire, avant de favoriser les processus de maturation.
    Abstract: Zusammenfassung Obwohl experimentelle und klinische Erfahrung darauf hinweisen, daß hohe Dosen von Testosteron zu einem frühzeitigen Wachstumsabschluß führen, sind der genaue Mechanismus und der eigentliche Wirkungsort dieses Hormons im Wachstumsapparat der Röhrenknochen unbekannt geblieben. In diesem Experiment wurden 200 g schweren männlichen Ratten supraphysiologische Testosterondosen injiziert, um die submikroskopischen Auswirkungen auf die verschiedenen Zonen des Epiphysenknorpels zu beobachten. In der Zone der Zellmitosen fand sich eine erhöhte Anzahl von sich teilenden Zellen. Die reifenden Zellen häuften im Frühstadium ihres Lebenscyclus größere Mengen von Sekretionsprodukten an und schienen eine abruptere Hypertrophie durchzumachen. In der prähypertrophen Zone enthielt die interterritoriale Matrix Herde von früher und verfrühter Verkalkung, sowie dickere und längere Kollagenfasern als vergleichsweise in Kontrolltieren. Daraus wird geschlossen, daß bei unbehandelten Tieren sogar große Testosterondosen anfänglich eine Stimulation der Chondrocytenproliferation verursachen, bevor sie die Reifungsprozesse veranlassen.
    Notes: Abstract Although experimental and clinical experience indicates that large doses of testosterone lead to premature cessation of growth, the exact mechanism and precise site of action of this hormone on the growth apparatus of long bones remain unknown. In this study, plateaued male rats were injected with supraphysiologic doses of testosterone to observe the submicroscopic effects on the various zones of the epiphyseal cartilage. In the zone of cell division there were increased numbers of dividing cells. The maturing cells accumulated larger amounts of secretory products at earlier stages of their life cycle, and appeared to undergo a more abrupt hypertrophy. In the zone of prehypertrophy, the interterritorial matrix contained foci of early and premature calcification and thicker and longer collagen fibers than at comparable levels in controls. It is concluded that in intact animals, even large doses of testosterone initially cause a stimulation of chondrocyte proliferation, prior to promoting maturation processes.
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  • 19
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    Calcified tissue international 7 (1971), S. 81-92 
    ISSN: 1432-0827
    Keywords: Strontium ; Vitamin D3 ; Calcium ; Absorption ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des poulets normaux, âgés de 2 semaines, présentent une condition voisine d'une rachitisme grave, lorsqu'on les soumet pendant 7 jours à un régime pauvre en calcium (0,1%), riche en vitamine D3, et contenant une quantité stable de strontium, équimolaire à 1,2% de calcium. Alors que l'on pensait que le rachitisme induit par le strontium était lié à une inhibition directe de la calcification, il apparait qu'avant toute modification osseuse apparente, le strontium inhibe la production du CaPB induit par la vitamine D3, ainsi que le mécanisme d'absorption intestinale du calcium. Il semble que cet effet du strontium soit lié à sa participation dans le mécanisme normal de la régulation du calcium au cours de la synthèse de CaBP.
    Abstract: Zusammenfassung Normale, 2wöchige Kücken gerieten innerhalb von 7 Tagen in einen schweren, rachitisänhlichen Zustand, wenn sie eine calciumarme (0,1%0 und Vitamin D3-reiche Nahrung erhielten, welcher kaltes Strontium in einer Konzentration von 2,62% (molaraequivalent mit 1,2% Calcium) zugesetzt wurde. Während man früher vermutete, daß die “Strontium-Rachitis” nur durch eine direkte Inhibition der Verkalkung entstehe, konnte nun gezeigt werden, daß — bevor eine sichtbare Knochenveränderung eintritt — die Vitamin D3-gesteuerte Bildung von CaBP (calciumbindendes Protein) und gleichzeitig der Mechanismus der Calciumabsorption im Darm durch Strontium gehemmt wird. Die gefundenen Resultate weisen auf die Möglichkeit hin, daß dieser Strontiumeffekt auf dessen Interferenz mit dem normalen Mechanismus der Calciumregulation durch die CaBP-Syntheses zurückgeführt werden kann.
    Notes: Abstract Normal 2-week-old chicks, when fed a low-calcium (0.1%), vitamin D3-replete diet containig stable strontium at a level equimolar to 1.2% calcium, developed a severe rachiticlike condition within 7 days. Whereas formerly it was suspected that “strontium rickets” resulted from direct inhibition of calcification only, it was shown that, preceding any detectable bone change, strontium inhibited vitamin D3-induced CaBP production and, simultaneously, the intestinal calcium absorptive mechanism. The results suggest the possibility that this effect of strontium may be due to its interference with the normal mechanism of calcium regulation of CaBP synthesis.
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  • 20
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    Calcified tissue international 7 (1971), S. 175-190 
    ISSN: 1432-0827
    Keywords: Bone ; Human ; Age ; Glycosaminoglycans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les glycosaminoglycanes de l'os humain compact du fémur sont identifiés et leur concentration et distribution sont déterminées à partir de cas d'autopsie, d'âges variables, allant du nouveau-né à des sujets de 94 ans. L'absence d'altérations post-mortem des glycosaminoglycanes osseux est déterminée au niveau de l'os fémoral de chien, au bout de 72 heures. Le chondroitine-4-sulfate constitue le glycosaminoglycane majeur de l'os humain: de plus, une fraction mineure semble être constituée par l'acide hyaluronique. Les proportions de glycosaminoglycanes varient inversement en fonction, de l'âge chez des sujets en pleine croissance: mais aucun changement n'est observé plus tardivement. La distribution des glycosaminoglycanes est identique chez les sujets adultes. Seules de faibles différences, concernant cette distribution, sont relevées. Chez les sujets jeunes elles sont, peut-être, liées à des changements de poids moléculaire peu élevés ou au sulfate chondroitine sulfaté, peu élevé et, chez un sujet vieil à une proportion plus grande d'acide hyaluronique.
    Abstract: Zusammenfassung Die Glykosaminoglykane aus menschlicher Compacta des Oberschenkels wurden charakterisiert und ihre Konzentrationen und Muster an Autopsien von Menschen verschiedenen Alters (Neugeborene bis 94jährige) festgelegt. Fällungen mit Cetylpyridin und Fraktionierungsmethoden wurden angewendet. Am Hundefemur konnte festgestellt werden, daß sich das Glykosaminoglykanmuster im Knochen bis zu 72 Std post mortem nicht veränderte. Als wichtigstes Glykosaminoglykan des menschlichen Knochens wurde das Chondroitin-4-sulfat identifiziert; dazu wurde ein kleiner Anteil versuchsweise als Hyaluronsäure eingestuft. Die Konzentrationen der Glykosaminoglykane standen in umgekehrtem Verhältnis zum Alter des im Wachstum stehenden Menschen, jedoch wurde nach dessen Abschluß keine Veränderung mehr beobachtet. Das Glykosaminoglykanmuster sieht für alle erwachsenen Menschen ähnlich aus. Nur kleine Abweichungen von diesem Muster konnten bei jungen Menschen festgestellt werden; möglicherweise sind sie auf eine leichte Änderung im Molekulargewicht oder auf eine schwache Sulfatierung des Chondroitinsulfates zurückzuführen. Dies gilt ebenso für einen alten Menschen, dessen Knochen einen höheren Anteil an Hyaluronsäure aufweisen.
    Notes: Abstract Glycosaminoglycans from human femoral compact bone were characterized and their concentrations and patterns were determined in autopsy cases of various ages, newborn to 94 years of age. Cetylpyridinium precipitation and fractionation methods were used. Absence of postmortem changes of bone glycosaminoglycan pattern for as long as 72 hours was checked on dog femoral bone. Chondroitin-4-sulphate was identified as the predominating glycosaminoglycan of human bone; in addition a minor part was tentatively identified as hyaluronic acid. Concentrations, of glycosaminoglycans were inversely related to age in growing subjects, but no change was noted later in life. The glycosaminoglycan pattern had a similar appearance for all of the adult subjects. Only small deviations from this pattern had a similar for young subjects, possibly due to low molecular weight change or low sulphated chondroitin sulphate; and for one old subjects to a higher proportion of hyaluronic acid.
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  • 21
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    Calcified tissue international 8 (1971), S. 83-86 
    ISSN: 1432-0827
    Keywords: Bone ; Strontium ; Calcium ; Vitamin D ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des poulets sont nourris avec une alimentation contenant 0,5% de Ca et 0,5% de Sr, plus diverses concentrations de vitamine D3. La moitié des besoins en calcium pour la croisance corporelle chez le poulet est assurée par le Sr, tant que la concentration en Vitamine D3 est maintenue entre 500 et 1000 ICU/kg de nourriture. Les besoins totaux en calcium pour la croissance ne sont pas couverts par le Sr. Bien que Sr soit incorporé dans l'os lorsque l'alimentation renferme de faibles doses de vitamine D3, le contenu total en cendre, ainsi que le contenu en calcium, sont diminués.
    Abstract: Zusammenfassung Eine Untersuchung an Hühnern, welche Futter mit 0,5% Ca und 0,5% Sr und verschieden hohen Vitamin D3-Zusätzen erhielten, läßt vermuten, daß die Hälfte des für das Körperwachstum des Huhnes benötigent Ca durch Sr ersetzt werden kann, solange das Vitamin D3 in der Höhe von 500–1000 IE/kg Futter gehalten wurde. Die Gesamtmenge des für das Knochenwachstum benötigten Ca konnte jedoch nicht durch Sr ersetzt werden. Obschon Sr bei niederem Vitamin D3-Gehalt der Nahrung im Knochen eingebaut wurde, waren sowohl der totale Aschegehalt als auch der Calciumgehalt vermindert.
    Notes: Abstract An investigation involving chicks fed diets with 0.5% Ca and 0.5% Sr supplemented with various levels of vitamin D3 suggests that one-half of the Ca requirement of body growth in the chick is met by Sr as long as the vitamin D3 level was maintained at 500 to 1000 ICU/kg foodstuff. The entire Ca requirement for bone growth could not, however, be met by Sr. Even though Sr was incorporated into the bone when low levels of vitamin D3 were fed in the diet, the total ash content, as well as Ca content, was reduced.
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  • 22
    ISSN: 1432-0827
    Keywords: Pyrophosphate ; Cyclic 3′5′-AMP ; Parathyroid ; Adenyl cyclase ; Bone ; Resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'injection de pyrophosphate inorganique, à la concentration de 15 μmoles/h, au niveau de rats thyro-parathyréodectomisés, inhibe les effects de l'hormone parathyroidienne injectée, sur le calcium et le phosphate plasmatique et sur l'excrétion rénale du calcium, du phosphate, des peptides contenant l'hydroxyproline et de l'AMP 3′5′ cyclique. Inversement, l'injection de pyrophosphate ne provoque pas de changements significatifs sur les effects d'injection d'AMP 3′5′ cyclique sur le calcium et le phosphate du plasma, ou sur l'excrétion urinaire de calcium, phosphate et peptides contenant de l'hydroxyproline.
    Abstract: Zusammenfassung Wurde thyroparathyreoidektomierten Ratten anorganisches Pyrophosphat mit einer Geschwindigkeit von 15 μMol/Std infundiert, so blockierte dies die Wirkung der gleichzeitig laufenden Parathormoninfusion auf Plasmacalcium und-phosphat, sowie auf die renale Ausscheidung von Calcium, Phosphat, Hydroxyprolin-haltigen Peptiden und cyclischem 3′,5′-AMP. Hingegen bewirkte die Pyrophosphatinfusion keine signifikante Veränderung der Wirkung einer Infusion von zyklischem 3′,5′-AMP auf Plasmacalcium und-phosphat oder auf die Ausscheidung im Urin von Calcium, Phosphat und Hydroxyprolin-haltigen Peptiden.
    Notes: Abstract The infusion of inorganic pyrophosphate at a rate of 15 μmoles/h into thyroparathyroidectomized rats blocked the effects of parathyroid hormone infusion upon plasma calcium and phosphate, and upon the renal excretion of calcium, phosphate, hydroxyproline-containing peptides, and cyclic 3′5′ AMP. In contrast, pyrophosphate infusion caused no significant change in the effects of cyclic 3′5′ AMP infusion upon plasma calcium and phosphate, or upon the urinary excretion of calcium, phosphate, and hydroxyproline-containing peptides.
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  • 23
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    Calcified tissue international 8 (1971), S. 114-120 
    ISSN: 1432-0827
    Keywords: Bone ; Phosphonates ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'effet d'un diphosphonate, EHDP est étudié dans deux systèmes éxpérimentaux chez le rat: une ostéoporose par immobilisation locale et une ostéoporose générale induite par la cortisone. EHDP est susceptible de prévenir la perte osseuse localisée, induite par l'immobilisation chirurgicale de la patte arrière gauche, mais est inefficace à empêcher la perte osseuse par voie générale induite par l'administration de cortisone. L'action majeure de l'EHDP est la production de grandes quantités d'ostéoide: il a peu d'effet sur la résorption osseuse. Le manque de résultats constants dans les deux systèmes suggère que les troubles osseux d'étiologie générale ne peuvent être étudiés par atrophie osseuse locale.
    Abstract: Zusammenfassung Die Wirkung eines Diphosphonates (EHDP) wurde mit zwei verschiedenen Versuchsanordnungen an Ratten untersucht: lokale Immobilisationsosteoporose und generalisierte, durch Cortison hervorgerufene Osteoporose. EHDP konnte den lokalen Knochenschwund verhindern, der durch die chirurgische Immobilisierung des linken Hinterbeines entstand; es verhinderte jedoch den generalisierten, durch Cortisonverabreichung hervorgerufenen Knochenschwund nicht. Die hervorstechendste Wirkung von EHDP ist die Bildung von großen Osteoidmengen; es scheint auf die Knochenresorption nur einen kleinen Einfluß zu haben. Der Mangel an gültigen Befunden bei beiden Versuchsanordnungen läßt darauf schiließen, daß aus einer lokalen Knochenatrophie nicht auf eine durch generalisierten Knochenschwund charakterisierte Erkrankung extrapoliert werden kann.
    Notes: Abstract The effect of a diphosphonate, EHDP, was studied in two experimental models in the rat: local immobilization osteoporosis and systemic cortisone-induced osteoporosis. EHDP was able to prevent the local bone loss brought about by surgical immobilization of the left hind limb, but was ineffective in preventing the systemic bone loss produced by cortisone administration. The most prevalent action of EHDP is the production of large amounts of osteoid; it seems to have little effect on bone resorption. The lack of consistent findings in both models suggests that systemic bone-losing disorders cannot be extrapolated from local bone atrophy.
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  • 24
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    Calcified tissue international 8 (1971), S. 197-210 
    ISSN: 1432-0827
    Keywords: Fluorescence ; Calcium ; Collagen ; Chemistry ; Bone ; Dentine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des composants fluorescents de l'os et la dentine sont séparés des hydrolysats alcalins de leur marice sur des colonnes Sephadex C25 CM d'échange cationique. Les concentrations en fluorescence et le spectre d'excitation (λ max 330 nm) et d'émission (λ max 395 nm) sont les mêmes que ceux observés au niveau des matrices intactes et gélatinisées. Les paramètres de fluorescence ne sont pas altérés par hydrolyse. La filtration sur gel à l'aide de colonnes Sephadex G 10 perment de différencier le matériel isolé en deux composants, ayant la même fluorescence et la même absorption UV. La fluorescence est indépendante de pH de 3.5–9.5. Des études de dialyse et de filtration sur gel de matrices gélatinisées indiquent une association étroite du matériel fluorescent avec les chaines polypeptidiques de collagène.
    Abstract: Zusammenfassung Fluorescierende Bestandteile aus Knochen und Dentin wurden in Sephadex C25 CM Kationen-Austauschersäulen von alkalischen Hydrolysaten ihrer Matrices getrennt. Die Fluorescenzintensitäten sowie die Erregungs- (λ max 330 nm) und Emissions- (λ max 395 nm) Spektren waren dieselben wie bei intakten und gelatinisierten Matrices. Die Fluorescenzparameter wurden durch die Hydrolyse nicht verändert. Eine Gelfiltration über Sephadex-G10-Säulen trennte das isolierte Material in 2 Komponenten auf, welche gleiche Fluorescenz- und UV-Absorptionseigenschaften zeigten. Im pH-Bereich zwischen 3,5 und 9,5 war die Fluorescenz unabhängig vom pH. Dialysierversuche sowie Gelfiltrationsexperimente mitden gelatinisierten Matrices zeigten eine starkgefügte Bindung des fluorescierenden Materials mit den Polypeptidketten des Kollagens.
    Notes: Abstract Fluorescent components in bone and dentine were separated from alkaline hydrolysates of their matrices on Sephadex C25 CM cationic exchange columns. The fluorescence levels, and the excitation (λ max 330 nm) and emission (λ max 395 nm) spectra, were the same as those observed in the intact and gelatinised matrices. The fluorescence parameters were unaltered by the hydrolysis procedure. Gel filtration on Sephadex G. 10 columns further resolved the isolated material into two components with the same fluorescence and UV absorption properties. The fluorescence was independent of pH over the range 3.5–9.5. Dialysis and gel filtration studies on the gelatinised matrices indicated a firmly-bonded association of the fluorescent material with the collagen polypeptide chains.
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  • 25
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    Calcified tissue international 8 (1971), S. 172-176 
    ISSN: 1432-0827
    Keywords: Sodium ; Calcium ; Strontium ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une colonne faite de poudre d'os dégraissé peut discriminer le22Na et le85Sr ou le47Ca. Le sodium est absorbé et élué par une telle colonne à une vitesse plus rapide que les deux autres isotopes. Ces observations rendent inutiles d'admettre l'existence d'un processus actif comme explication principale du comportement différentiel du Na et de ces cations multivalents d'osin vivo.
    Abstract: Zusammenfassung Eine Säule bestehend aus entfettetem Knochenpulver erlaubt die Unterscheidung zwischen22Na und85Sr oder47Ca. Natrium wird von einer solchen Säule schneller aufgenommen und eluiert als die beiden anderen Isotopen. Die Annahme eines aktiven Prozesses als hauptsächliche Erklärung für das differenzierte Verhalten von Na und diesen multivalenten Kationen im Knochenin vivo wird auf Grund dieser Beobachtung überflüssig.
    Notes: Abstract A column constructed of defatted bone powder can discriminate between22Na and58Sr or47Ca. Sodium is taken up, and eluted, from such a column at a more rapid rate than the other two isotopes. These observations make it unnecessary to assume the existence of an active process as a major explanation for the differential behaviour of Na and these multivalent cations in bonein vivo.
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  • 26
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    Calcified tissue international 8 (1971), S. 211-216 
    ISSN: 1432-0827
    Keywords: 45Calcium ; 85Strontium ; Bone ; Tissue Culture ; Isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des calottes craniennes d'embryons de poulet sont cultivées à l'état vivant et après mortification selon divers procédés. L'absorption de45Ca et85Sr est mesurée et il apparait que les calottes vivantes et mortifiées prennent du calcium au détriment du strontium. Cette action au niveau de l'os vivant à 37°, est généralement plus intense que celle observée au niveau de l'os mortifié ou celle de l'os vivant cultivé à 4°. Cependant cette absorption préférenttielle n'avoisine pas les concentrations prévues par la physico-chimie, ce qui laisse penser que l'action anti-strontium est modifiée par la nature des cristaux osseux et leur environnement.
    Abstract: Zusammenfassung Calvarien von Kückenembryonen wurden lebend oder nach Abtöten mittels verschiedener Techniken gezüchtet. Die Aufnahme von45Ca und85Sr wurde gemessen, und es zeigte sich, daß sowohl die lebenden wie die toten Calvarien Calcium gegenüber Strontium vorzogen. Die Bevorzugung war im allgemeinen im lebenden Knochen bei 37° höher als im toten Knochen oder im lebenden, bei 4° gezüchteten Knochen. Jedoch erreichte diese Bevorzugung nicht den anhand physikochemischer Überlegungen vorausgesagten Grad. Dies läßt vermuten, daß die Calciumbevorzugung gegenüber Strontium durch die Natur der Knochenkristalle und deren Umgebung modifiziert wird.
    Notes: Abstract Embryonic chick calvaria were cultured alive and after killing by various procedures. The uptakes of45Ca and85Sr were measured and it was found that both live and dead calvaria discriminated against strontium in favour of calcium. The discrimination in live bone at 37° was usually higher than that in dead bone or that in live bone cultured at 4°. However, discrimination did not approach the physicochemically predicted level, which suggests that discrimination against strontium is modified by the nature of the bone crystals and their environment.
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  • 27
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    Calcified tissue international 8 (1971), S. 190-196 
    ISSN: 1432-0827
    Keywords: Bone ; Tetracycline ; Somatotrophin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une nouvelle méthode d'analyse morphométrique au microscope optique de coupes non déminéralisées d'os, qui permet de déterminer l'augmentation de la masse d'os cortical en fonction du temps, est présentée. Cette méthode est basée sur le marquage continu et de longue durée de l'os néoformé par la tétracycline pendant la période expérimentale. En outre, on peut effectuer une comparaison entre la durée de formation d'os nouveau pendant des périodes de contrôle et d'expérience, en administrant une molécule fluorescente différente pendant la période témoin. L'os déposé, pendant cette dernière phase, est ainsi marqué dans une couleur différente. En connaissant les différences de durée de formation entre les deux périodes, on peut préciser le mécanisme d'augmentation de la masse osseuse. Des études expérimentales sur l'influence de l'hormone de croissance sur la masse corticale squelettique de chiens adultes des deux sexes sont présentées comme des exemples de cette méthode.
    Abstract: Zusammenfassung Es wird eine neue Methode zur Messung der Zunahme der kortikalen Knochenmasse in Funktion der Zeit beschrieben. Dies geschieht durch morphometrische Analyse von Schnitten undemineralisierten Knochens unter dem Mikroskop. Die Methode stützt sich auf die kontinuierliche Langzeitmarkierung von neuem Knochen mit Tetracyclin während der Dauer des Experimentes. Zusätzlich kann die Geschwindigkeit der Knochenzunahme während der Kontrollperiode mit derjenigen während des Experimentes verglichen werden, indem während der Kontrollperiode eine andere fluoreszierende Substanz verabreicht wird. Somit wird aller Knochen, der während der Kontrollperiode abgelagert wird, in einer verschiedenen Farbe markiert. Die Kenntnis der Unterschiede der Bildungsgeschwindigkeiten zwischen der Kontroll- und der Experimentier-Periode ermöglicht zusätzliche Einblicke in den Mechanismus, durch welchen die Zunahme der Knochenmasse herbeigeführt wird. Als Beispiel für die Anwendung dieser Methode werden experimentelle Untersuchungen über den Einfluß des Wachstumshormones auf die kortikale Skelettmasse bei erwachsenen Hunden beiden Geschlechts angegeben.
    Notes: Abstract A new method is presented by which an increase in cortical bone mass over time can be determined from morphometric analysis of sections of undemineralized bone under the optical microscope. The method depends on the long-duration, continuous labeling of new bone by tetracycline during the experimental period. In addition, a comparison of the rates of new bone formation in the control and experimental periods can be made by administering a different fluorescent molecule during the control period. All bone deposited during the control period is thus labeled with a different color. By knowing the differences in rates of formation between control and experimental periods, additional insight is gained into the mechanism by which the increase in bone mass is produced. Experimental studies on the influence of growth hormone on the cortical skeletal mass in adult dogs of both sexes are presented as examples of the use of this method.
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  • 28
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    Calcified tissue international 8 (1971), S. 287-303 
    ISSN: 1432-0827
    Keywords: Calcification ; Bone ; Matrix ; Apatite ; Nucleation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Du collagène d'os compact de mouton est préparé par décalcification dans I'EDTA et à partir de tendons de queux de rats, par extraction dans l'acide acétique et reconstitution dans NaCl. Le dépôt d'apatite dans le collagène osseux de mouton dans une solution de calcification métastable est étudié chimiquement et par microscopie électronique. Le collagène osseux est un bon catalyseur de nucléation pour le dépôt minéral, alors que le collagène de tendons de rat ne l'est pas. Le dépôt minéral du collagène osseux se produit en deux phases cinétiques séparées, une phase rapide de nucléation et une croissance cristalline, donnant naissance à de petits ilots calcifiés et une seconde phase lente de croissance dans des régions ne comportant pas de zones catalytiques. La seconde phase de dépôt minéral paraît être le résultat d'une diffusion inhibée d'ions à travers les fibrilles collagènes alignées, laissant de larges régions de collagène sans minéral, bien que le tampon reste hautement sursaturé. La microscopie électronique permet de penser que les zones de catalyse pourraient avoir un rapport avec la périodicité de 640 Å de collagène, mais l'importance d'un matériel noncollagènique, lié au collagène, n'est pas à exclure. L'activité catalytique faible du collagène reconstitué n'est pas liée à la présence d'inhibiteurs faiblement liés, bien que des inhibiteurs puissent être intimement liés à ce type de collagène, qui pourrait être absent du collagène osseux. La différence d'activité catalytique pourrait intervenir dans la calcification physiologique. Une hypothèse plus générale pour la nucléation de la phase minérale dans les systémes biologiques est nécessaire.
    Abstract: Zusammenfassung Kollagen wurde aus kompaktem Schafsknochen mittels EDTA-Entkalkung und aus Rattenschwanzsehnen durch Essigsäureextraktion und Rekonstitution mit NaCl gewonnen. Die Apatitablagerung aus einer metastabilen Verkalkungslösung auf Schafsknochenkollagen wurde chemisch und im Elektronenmikroskop untersucht. Es zeigte sich, daß das Knochenkollagen ein guter Nukleationskatalysator für die Mineralablagerung ist, was beim Rattenschwanzkollagen nicht zutraf. Im Knochenkollagen erfolgte die Mineralablagerung in zwei getrennten kinetischen Phasen: einer raschen Phase der Nukleation und des Kristallwachstums, welche kleine verkalkte Inseln entstehen läßt, und einer zweiten langsamen Phase, welcher das Wachstum in Bezierken, die keine katalytischaktiven Stellen einschließen, zuzuschreiben ist. Diese zweite Phase der Mineralablagerung wird als Resultat einer verminderten Ionendiffusion durch die enganeinanderliegenden Kollagenfibrillen angesehen, wodurch weite Kollagenbereiche ohne Mineral bleiben, obwohl der Puffer stark übersättigt ist. Elektronenmikrographien ließen vermuten, daß die katalytischaktiven Stellen in einem gewissen Verhältnis zur 640 Å-Periodizität des Kollagens stehen; es konnte jedoch nicht ausgeschlossen werden, daß nicht-kollagenhaltiges Material, welches an Kollagen gebunden ist, ebenfalls eine Rolle spielt. Die schlechte katalytische Aktivität des rekonstituierten Kollagens konnte nicht auf die Anwesenheit von schwachgebundenen Hemmstoffen zurückgeführt werden, obwohl Inhibitoren stark an dieses Kollagen gebunden sein könnten, die jedoch im Knochenkollagen nicht vorhanden sind. Die Unterschiede in der katalytischen Aktivität können mit der physiologischen Verkalkung in Beziehung stehen. Eine allgemeinere Hypothese für die Nukleation einer Mineralphase in biologischen Systemen wäre erforderlich.
    Notes: Abstract Collagen was prepared from compact sheep bone by decalcification with EDTA and from rat tail tendons by acetic acid extraction and reconstitution with NaCl. The deposition of apatite in sheep bone collagen in a metastable calcification solution was studied chemically and by electron microscopy. The bone collagen was shown to be a good nucleation catalyst for mineral deposition, while rat tail collagen was a poor catalyst. Mineral deposition in bone collagen occured in two separate kinetic phases, a rapid phase of nucleation and crystal growth, giving rise to small calcified islands, and a second slow phase, ascribed to growth in regions not involving the catalytic sites. This second phase of mineral deposition is considered to be the result of impaired ion diffusion through the closely-aligned collagen fibrils, thus leaving large areas of the collagen free of mineral even though the buffer remains highly supersaturated. Electron micrographs suggested that the catalytic sites might be in some relationship to the 640 Å periodicity of collagen, but a role for non-collagenous material bound to the collagen has not been excluded. The poor catalytic activity of reconstituted collagen was not due to the presence of loosely-bound inhibitors, although inhibitors could be strongly bound to this type of collagen and be absent from bone collagen. The differences in catalytic activity may have a bearing on physiological calcification. A more general hypothesis for nucleation of a mineral phase in biological systems is required.
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  • 29
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    Calcified tissue international 7 (1971), S. 264-266 
    ISSN: 1432-0827
    Keywords: Hydroxyl ; Apartite ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
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    Calcified tissue international 7 (1971), S. 259-263 
    ISSN: 1432-0827
    Keywords: Hydroxyl ; Apartite ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
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    Calcified tissue international 8 (1971), S. 73-82 
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Phosphorus ; Sodium ; Magnesium ; Electron probe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'analyse par microsonde électronique, technique récente, a été peu utilisée pour l'étude du tissu osseux. Le rapport molaire Ca/P a été mesuré pour l'os normal et certains os pathologiques. Les résultats sont en accord avec ceux obtenus par les autres méthodes, en particulier la microradiographie. La microsonde électronique permet le dosage du sodium et du magnésium, constituants secondaires de l'os, à l'échelle microscopique. Nos observations mettent en évidence l'hétérogénéité de la distribution de ces éléments: concentration élevée dans l'os jeune (ostéone), moindre dans l'os interhaversien. Ces résultats sont en accord avec l'hypothèse de Neuman de l'absorption des ions sodium et magnésium à la surface du crystal d'apatite.
    Abstract: Zusammenfassung Die Mikroanalyse mittels Elektronensonde ist eine neue Technik für die Untersuchung von Knochen; die Bedingungen für eine richtige Interpretation der Resultate werden beschrieben. Das molare Ca/P-Verhältnis wurde in normalen und in drei pathologischen Knochen gemessen. Diese Messungen wurden in verschiedenen Regionen des corticalen Knochens durch-geführt. Die Resultate stimmen mit den durch Mikroradiographie erhaltenen überein. Mikroanalysen mittels der Elektronensonde ermöglichten es, die Verteilung von Na und Mg in den zwischenhaversschen und haversschen Geweben von corticalem Knochen Erwachsener zu untersuchen. Unsere Beobachtungen zeigen die heterogene Verteilung dieser Elemente. In Übereinstimmung mit der Hypothese der Ionen-Absorption an der Oberfläche des Apatitkristalles sind die Konzentrationen in jungen Knochen (Oesteonen) höher.
    Notes: Abstract Electron probe microanalysis is a recent technique for the study of bone and the conditions for the correct interpretation of the results are described. The Ca/P molar ratio was measured in normal and in three pathological bones. These measurements were carried out in different regions of cortical bone. The results are in agreement with the results obtained by microradiography. Microprobe analysis, however, allows the measurement of elements at the microscopic level. Electron probe microanalysis was used to study the distribution of sodium and magnesium in the interhaversian and haversian tissues of adult cortical bone. Observations show the heterogeneity of distribution of these elements. Concentrations are higher in young bone (osteons), in agreement with the hypothesis of ion absorption on the surface of the apatite crystal.
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    Calcified tissue international 8 (1971), S. 36-53 
    ISSN: 1432-0827
    Keywords: Phospholipids ; Vitamin D ; Deficiency ; Epiphysis ; Cartilage ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les effets de divers degrés de rachitisme non compliqué, provoqué par avitaminose D, sur les concentrations, la composition, et l'extractibilité de phospholipides de tissus moux et en voie de calcification ont été étudiés chez le poulet et le porc. Le contenu en phospholipides des tissus en voie de calcification est modifié au cours du rachitisme; cependant, on n'a constaté que peu de changements dans les tissus moux. Les effets quantitatifs sur la concentration en lipides des tissus rachitiques calcifiés varient de zone en zone et semblent indiquer desvariations dans d'autres constituants tissulaires. Cependant les différences qualitatives indiquent un effet direct sur des phospholipides spécifiques. Les phospholipides acides présentent les changements de pourcentage les plus élevés bien que de nombreuses modifications statisstiquement significatives dans les phospholipides neutres ont pu être observés. Les zones stisulaires présentant le plus grand changement de composition phospholipidique au cours du rachitisme, sont constituées par le cartilage hypertrophique et en voie de prolifération et par l'os spongieux, alors que le cartilage calcifié est le moins affecté. Le rachitisme diminue aussi l'extractibilité de certains phospholipides neutres et acides des zones de minéralisation précoce. Ces résultats semblent indiquer la présence, dans le tissu rachitique, de concentrations élevées de phospholipide complexé avec le phosphate de calcium, probablement causé par l'inhibition de la minéralisation normale.
    Abstract: Zusammenfassung Die Auswirkung von verschiedenen Graden von Rachitis (verursacht durch Vitamin D-Mangel) auf die Mengen, die Zusammensetzung und auf die Extrahierbarkeit der Phospholipide von verkalkenden und weichen Geweben wurde an Hühnern und Schweinen untersucht. Es wurden verschiedene Wirkungen von Rachitis auf die Phospholipid-Zusammensetzung der verkalkenden Gewebe gefunden, in den weichen Geweben jedoch nur wenige. Der Grad dieser Wirkung auf die Lipid-Konzentration der rachitisch verknöchernden Gewebe änderte sich von Schicht zu Schicht und schien die Änderungen in anderen Gewebebestandteilen wiederzugeben. Die qualitativen Unterschiede zeigten jedoch eine direkte Wirkung auf spezifische Phospholipide an. Saure Phospholipide zeigten den größten prozentualen Unterschied, obgleich zahlreiche statistisch signifikante Unterschiede auch in den neutralen Phospholipiden gefunden wurden. Die Gewebeschichten, welche bei Rachitis die größte Änderung in der Phospholipidzusammensetzung zeigten, waren proliferierender und hypertrophischer Knorpel und spongiöser Knochen, während verkalkter Knorpel die geringste Änderung zeigte. Rachitis verminderte auch die Extrahierbarkeit von gewissen sauren und neutralen Phospholipiden aus den Schichten der frühen Mineralisierung. Diese Ergebnisse weisen auf das Vorhandensein von erhöhten Phospholipidmengen im rachitischen Gewebe hin, welche Calciumphosphat binden; dies wird wahrscheinlich durch die Blockierung der normalen Mineralisierung verursacht.
    Notes: Abstract The effect of various degrees of simple, vitamin D-deficient rickets on the levels, composition and extractability of phospholipids from calcifying and soft tissues was studied in chickens and pigs. A variety of effects of rickets on the phospholipid composition of the calcifying tissues were detected; there was little change in the soft tissues. The quantitative effects on the lipid concentration of rachitic hard tissues were variable from zone to zone and appeared to reflect variations in other tissue constituents. However, the qualitative differences indicated a direct effect on specific phospholipids. Acidic phospholipids displayed the greatest percentage change, although numerous statistically-significant changes were also seen in the neutral phospholipids. Tissue zones displaying the greatest change in phospholipid composition in rickets were proliferating and hypertrophic cartilage, and cancellous bone, with calcified cartilage showing the least effect. Rickets also reduced the extractability of certain acidic and neutral phospholipids from zones of early mineralization. These findings are interpreted as indicating the presence of elevated levels of phospholipid complexed with calcium phosphate in rachitic tissue, presumably due to the blockage of normal mineralization.
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    Calcified tissue international 8 (1971), S. 96-105 
    ISSN: 1432-0827
    Keywords: Iliac ; Proteinpolysaccharides ; Cartilage ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les protéines-polysaccharides (PP) ont été extraits de la crête iliaque cartilagineuse d'enfants à squelettes normaux, âgés de quelques jours à 16 ans, à l'aide de technique par rupture et par dissociation. L'homogénéisation du cartilage dans l'eau ou l'agitation dans du chlorure de guanidinium permet de recueillir un matériel PP semblable à poids moléculaire élevé. Les extraits aqueux contiennent des quantités considérables de collagène qu'on ne trouve qu'à l'état de trace dans les extraits à la guanidine. Des produits dégradés, probablement liés à l'action d'enzymes protéolytiques, sont obtenus après extraction du tissu avec un tampon phosphate 0,067 M de pH 7,4 à 30°; 0,5 M ou 3,0 M MgCl2 à 10°.
    Abstract: Zusammenfassung Proteinpolysaccharide wurden aus dem Beckenkamm-Knorpel von Kindern im Alter von wenigen Tagen bis 16 Jahren mit normalem Skelett extrahiert, und zwar sowohl durch Homogenisierung als auch durch Extraktionsmethoden. Die Homogensierung des Knorpels in Wasser ergab Proteinpolysaccharide von hohem Molekulargewicht und gleichen Eigenschaften wie nach Rühren mit Guanidinchlorid. Die wässerigen Extrakte enthielten ansehnliche Kollagenmengen, während in den Guanidinextrakten nur Spuren vorlagen. Abbauprodukte, die wahrscheinlich durch Einwirkung von proteolytischen Enzymen entstanden, wurden durch Extraktion dieses Gewebes mit 0,067 M Phosphatpuffer von pH 7,4 bei 30°, ferner mit 0,5 oder 3,0 M MgCl2 bei 10° gewonnen.
    Notes: Abstract Proteinpolysaccharides (PP) have been extracted from the iliac crest cartilage of skeletally normal children varying in age between a few days and sixteen years, with both disruptive and dissociative methods. Homogenization of the cartilage in water or stirring with guanidinium chloride yielded high molecular weight PP material of similar properties. The water extracts contained considerable amounts of collagen which was present only in traces in the guanidine extracts. Degraded products, probably due to the action of proteolytic enzymes, were obtained by extraction of the tissue with 0.067 M phosphate buffer pH 7.4 at 30°; 0.5 M or 3.0 M MgCl2 at 10°.
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    Calcified tissue international 8 (1971), S. 265-275 
    ISSN: 1432-0827
    Keywords: Calcium ; Vitamin D ; Zinc ; Bone ; Teeth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Deux groupes de rats sevrés sont soumis à une alimentation contenant un excès de zinc, une faible quantité de calcium avec ou sans vitamine D. Deux tiers des animaux dans les deux groupes sont sacrifiés respectivement après cinq et dix semaines, alors que les animaux restants sont soumis à ce régime pendant cinq semaines, puis, pendant les cinq semaines suivantes, reçoivent les régimes correspondants, avex une concentration normale de zinc. Des études histologiques et microradiographiques sont réalisées sur l'humérus et les incisives. L'effet porotique connu des régimes pauvres en calcium et normaux en vitamine D est notablement augmenté avec un excès de zinc. Après avoir ramené le zinc à la normale, la gravité de l'ostéoporose est réduite à celle recontrée au cours de concentration faible en calcium, avec peu d'effet sur la dentine. L'absence de vitamine D, dans les régimes à contenu élevé en zinc et faible en calcium, provoque des changements porotiques et ostéomalaciques des os, alors que le ratrait consécutif de l'excès de zinc provoque une ostéomalacie typique. La dentine est nettement atteinte et des bandes alternantes de tissus bien mal minéralisés sont observées. En ajustant le zinc ingéré à une concentration normale, de larges couches de dentine non minéralisée sont observées avec une bande étroite de tissu minéralisée. En l'absence de vitamine D, l'excès de zinc semble exercer un effet porotique sur l'os et un effet de minéralisation sur la dentine, alors qu'il augmente l'effet porotique au niveau de l'os lorsque la vitamine est présente.
    Abstract: Zusammenfassung Zwei Gruppen entwöhnter Ratten wurden mit Calcium-armen Futter mit oder ohne Vitamin D-Zusatz und einem Zinküberschuß ernährt. Zwei Drittel der Tiere in beiden Gruppen wurden nach 5, beziehungsweise nach 10 Wochen getötet, während die übrigen Tiere dieses Futter während 5 Wochen erhielten und anschließend für weitere 5 Wochen die entsprechende Nahrung mit einem normalen Zinkgehalt bekamen. Die Humeri und die Schneidezähne wurden dann histologisch und mikroradiographisch untersucht. Der bekannte porotische Effekt der Calcium-armen, normal Vitamin D-haltigen Nahrung war bei Zinküberschuß deutlich erhöht. Wurde die Zinkaufnahme zur Norm gebracht, so reduzierte sich der Grad der Porose auf denjenigen, der typisch für niedrige Calcium-Einnahmen ist, mit wenig Wirkung auf das Dentin. Fehlte das Vitamin D in der Zink-reichen und Calcium-armen Nahrung, so entstanden in den Knochen sowohl porotische als auch osteomalazische Veränderungen; nach Absetzen des Zinküberschusses jedoch entstanden typische Anzeichen einer Osteomalacie. Das Dentin wurde stark angegriffen, und es wurden abwechslungsweise Banden von normal und schlecht mineralisiertem Gewebe beobachtet. Wenn die Zinkeinnahme zur Norm gebracht wurde, so entstanden breite Säume von unverkalktem Dentin mit einer schmalen Bande von mineralisiertem Gewebe. Bei Fehlen von Vitamin D scheint der Zinküberschuß eine porotische Wirkung auf den Knochen und eine verkalkende Wirkung auf das Dentin zu haben; dieser Überschuß erhöht den Grad der Knochenporose auch in Anwesenheit des Vitamins.
    Notes: Abstract Two groups of weanling rats were maintained on diets containing an excess of zinc, with low calcium intake and with, or without, added vitamin D. Two thirds of the animals in the two groups were killed after five and ten weeks respectively while the remainder received these diets for five weeks and were then maintained for a further five weeks on the corresponding diets with a normal level of zinc. Histological and microradiographical observations of the humeri and incisors were then carried out. The known porotic effect of low calcium-normal vitamin D diets was markedly increased in zine excess. After adjusting the intake of zinc to normal, the degree of porosis was reduced to that typical of low calcium conditions, with little effect on the dentine. Absence of vitamin D from the zinc-low calcium diet resulted in both porotic and osteomalacic changes in the bones, while subsequent removal of the zinc excess resulted in a condition typical of osteomalacia. Dentine was drastically affected and, alternating bands of poorly and adequately-mineralized tissue were observed. Adjusting the zinc intake to normal resulted in wide seams of unmineralized dentine with a narrow band of mineralized tissue. In the absence of vitamin D, zinc excess appears to exert a porotic effect in bone and a mineralizing effect in dentine, while it also increases the degree of porosis found in bone when the vitamin is present.
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    Experimental brain research 12 (1971), S. 379-388 
    ISSN: 1432-1106
    Keywords: Electron microscopy ; Spinal cord ; Neurone ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Quantitative electron microscopical observations have been made on the afferent synaptology of neurones in laminae V and VII of the cervical spinal cord of the cat. Both laminae contain large bouton-covered polydendritic neurones of the type seen in the brainstem reticular formation. Each lamina contains two other categories of neurone. One of these, in lamina V, is peculiar in having a very high proportion of afferent boutons filled with dense-core vesicles; similar neurones exist in lamina VII, but their presynaptic afferents do not contain unusual quantities of dense-core vesicles. The third type of neurone in laminae V and VII seems to be identical with an oligodendritic neurone type found in the brainstem reticular formation and parafascicular-centromedian complex.
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    Experimental brain research 12 (1971), S. 447-456 
    ISSN: 1432-1106
    Keywords: Electron microscopy ; Cerebellum ; Purkinje cells ; Diphenyl-hydantoin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopic examination of Purkinje Cells was performed in sections from the cerebellum of three albino rats aged 4 1/2 month, intoxicated with diphenylhydantoin for 51 days. Three untreated albino rats served as controls. There were no difference between the substructure of the Purkinje cells from the two groups of animals. It was concluded that diphenylhydantoin in toxic but sublethal doses does not change the substructure of the Purkinje cells.
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    Experimental brain research 13 (1971), S. 451-460 
    ISSN: 1432-1106
    Keywords: Psychotropic drugs ; Rabbit hippocampus ; Glycogen ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following administration of psychotropic drugs, the brains of rabbits were examined by electron microscopy, with special references to glycogen granules in the hippocampus, and were compared with the normal materials. After seven days' intramuscular injections of chlorpromazine (15 mg/kg/day) or trifluoperazine (10 mg/kg/day), glycogen granules appeared diffusely in the perikaryal cytoplasm of the pyramidal cells and small nerve cells and in the myelinated nerve fibers, and were accumulated in the dendrites of pyramidal cells and in the astrocytic cytoplasm. Those animals showed neuroleptic symptomes and extrapyramidal ones throughout the period. The administration of the drugs might inhibit the glycolytic metabolism in neurons and glial cells of the hippocampus.
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    Cell & tissue research 114 (1971), S. 61-72 
    ISSN: 1432-0878
    Keywords: Corpora cardiaca ; Neurosecretion ; Insects ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les corpora cardiaca de l'adulte de Locusta migratoria sont formés de deux régions bien individualisées ce qui nous a permis de reconnaître la sécrétion propre des différents types de neurosécrétion. Dans la région nerveuse, nous distinguons par la taille des grains trois types de neurosécrétion dense classique et un quatrième type d'aspect clair. Dans la région »propre« non nerveuse, les cellules ont des caractères nettement endocriniens et sont mélangées à un seul type d'axones neurosécréteurs.
    Notes: Summary The corpora cardiaca of adult Locusta migratoria consist of two well separated areas, a fact which permits the differentiation between intrinsic and extrinsic neurosecretory material. In the neural area three types of electron dense “classical” neurosecretory granules, and a fourth more lucent type can be distinguished according to size. In the non-neural “glandular” area typical endocrine cells mingle with only one type of neurosecretory axons.
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    Cell & tissue research 115 (1971), S. 565-578 
    ISSN: 1432-0878
    Keywords: Testis ; Reptiles ; Sertoli cells ; Glycogen ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les cellules de Sertoli du testicule de Lacerta vivipara ont été étudiées en microscopie électronique chez des animaux récoltés entre le printemps et l'automne pendant deux années et chez des animaux hypophysectomisés en automne. Ces cellules contiennent de nombreuses mitochondries de petite taille à crêtes lamellaires, des ribosomes libres, un reticulum endoplasmique lisse moyennement développé, plusieurs petits dictyosomes formant l'appareil de Golgi, des liposomes et des microtubules. Elles renferment aussi de nombreux corps denses de grande taille qui paraissent être de nature lysosomiale. Le glycogène a été particulièrement étudié. Il est formé de particules β dispersées au hasard dans le hyaloplasme. Des variations saisonnières dans la teneur en glycogène ont été notées. Chez les hypophysectomisés, les cellules de Sertoli contiennent de grandes quantités de ce métabolite dont les particules sont concentrées dans des petites plages, souvent autour des liposomes. Les rôles possibles des cellules de Sertoli sont discutés: soutien et apport de nourriture aux cellules germinales, production d'hormones et phagocytose des corps résiduels. Les variations de la teneur en glycogène sont également discutées.
    Notes: Summary Sertoli cells of the testis of Lacerta vivipara have been studied electron microscopically in animals obtained between spring and autumn during two years and in animals hypophysectomized in autumn. These cells contain numerous small mitochondria with lamellar cristae, free ribosomes, smooth endoplasmic reticulum moderately developed, several small dictyosomes forming the Golgi complex, lipid droplets and microtubules. There are numerous dense bodies of large size with an heterogeneous content which seem to be of lysosomial nature. Glycogen consists of β particles dispersed at random in the hyaloplasm. Seasonal variations in the content of glycogen are noted. In hypophysectomized animals Sertoli cells contain large amounts of that metabolite whose particles are concentrated in small areas often around the lipid droplets. Possible role of the Sertoli cells concerning mechanical support and nutrition of the germinal cells, production of hormones and phagocytosis of residual bodies are discussed. The variations in the glycogen content are also discussed.
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    Cell & tissue research 118 (1971), S. 97-112 
    ISSN: 1432-0878
    Keywords: Stratum corneum ; Man ; Non-fixed ; Non-dehydrated ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This is an electron microscopic study of non-fixed and non-dehydrated normal human stratum corneum from the lumbar region. Non-stained sections have a low contrast. In sections examined 3 days after skin biopsy the cytoplasm of the cells shows a uniform contrast or exhibits dark and light areas. A single layer delimits the cytoplasm from the intercellular space. The latter is partly filled out with substance. In sections stained 2 to 4 days after skin biopsy the fibrils are distinct. On the basis of the variations in their opacity and ultrastructure three types of horny cells are clearly distinguishable. In cells of type 1 intensely stained keratohyalin and less opaque fibrillar substance occur. A distinct keratin pattern is not found. In cells of type 2 the fibrils show areas with distinct kerytohyalin and keratin pattern and transitional phases between these two stages of fibrillar differentiation. The keratin pattern representing the final stage of the fibrillar differentiation process is visualized through a successive “discoloration” of the filaments, whereas the interfilamentous substance retains the opacity of the keratohyalin. In cells of type 3 the entire fibrillar substance exhibits a keratin pattern. This consists of less opaque filaments with a diameter of 74 Å. The septa representing the interfilamentous substance are estimated as 30 Å at their thinnest points. These observations of the fibrils are completely comparable to the findings in fixed and dehydrated normal human stratum corneum. In sections stained particularly more than 18 days after skin biopsy the fibrils exhibit pronounced changes in their staining properties with concomitant decrease in distinctness or a complete extinction of the keratin pattern. The observations of the modified plasma membrane and the intercellular space in stained sections correspond to the findings in fixed and dehydrated normal human stratum corneum. The modified plasma membrane and the structures in the intercellular space appear with equal distinctness, whether the sections are stained 2 to 4, 6 to 12 or 14 to 21 days after skin biopsy.
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    Cell & tissue research 118 (1971), S. 467-481 
    ISSN: 1432-0878
    Keywords: Neutrophilic promyelocyte ; Human bone marrow ; Primary granulogenesis ; Phase contrast microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developmental changes in the neutrophilic promyelocytes from normal human bone marrow have been analyzed by means of phase contrast and electron microscopy. This developmental phase is characterized by the elaboration of primary (azurophillysosomal) granules and the entire intracellular machinery is directed principally toward this goal. The promyelocyte stage has been subdivided into three arbitrary stages based upon morphological, histochemical and functional characteristics which relate to the onset, active production and cessation of primary granulogenesis.
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    Cell & tissue research 119 (1971), S. 120-146 
    ISSN: 1432-0878
    Keywords: Red muscle ; Fibre types ; Small mammals ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Fasern des roten und langsamen M. soleus von Ratte, Kaninchen und Katze und des roten, jedoch schnellen, M. vocalis des Kaninchens wurden licht- und elektronenmikroskopisch untersucht und mit den verschiedenen Fasertypen aus dem M. tibialis anterior der Ratte und dem M. gastrocnemius des Kaninchens und der Katze verglichen. M. soleus und M. vocalis (einschließlich M. thyreoarytenoideus) enthalten nur einen mitochondrienreichen Fasertyp. Im schnellen M. vocalis ist der Z-Streifen schmal (50–60 nm), das sarcoplasmatische Reticulum ist gut entwickelt. Die Anordnung von Reticulum und Mitochondrion ist ähnlich wie in Herzmuskelzellen. Wie auch in anderen langsamen Muskeln verschiedener Tiere ist im M. soleus der Z-Streifen breit (100–120 nm), Triaden und Reticulum sind selten, und die Filamente bilden unregelmäßige Areale anstelle von Fibrillen. Hierin gleichen die Fasern des M. soleus den (mitochondrienreichen) C-Fasern eines entsprechenden gemischten Muskels; dagegen zeigen die Zwischentyp-(B-)Fasern schmale Z-Linien (50–70 nm), isodiametrische Fibrillen und mehr Triaden als die C-Fasern. Entgegen der bisherigen Vermutung, die auf der histochemischen Zuordnung der SoleusFasern zum Typ B und der Vocalis-Fasern zum Typ C beruht, ist daher anzunehmen, daß die langsamen motorischen Einheiten eines gemischten Muskels aus C- und nicht aus B-Fasern bestehen. In einigen Muskeln sind die Sarcomere der C-Fasern länger als die der B-(und A-) Fasern. Im M. tibialis anterior der Ratte verschwindet der Unterschied von 8,5% bei 2,6 μm Sarcomerlänge bei der Dehnung auf 2,8 μm mittlere Sarcomerlänge; vermutlich weil die Ruhedehnungskurve zunehmend steiler wird. Die isometrische Extraspannung im Tetanus ist bei 120% der Ruhelänge, d.h. bei 2,7 μm Sarcomerlänge. am größten. Daher muß bei 2,6 μm mittlerer Sarcomerlänge die Kraft der C-Fasern die der B-Fasern übertreffen. Rote Muskeln sind besser vaskularisiert als weiße Muskeln. Für die Mm. soleus und gastrocnemius der Katze verhalten sich die Kapillardichten (Kapillaren/mm2 Muskelfaserquerschnitt) wie 2,7∶:1. Dieser Wert entspricht dem Verhältnis zwischen den Größen für die Durchblutung (ml/min × 100 g) in Ruhe und bei maximaler Gefäßerweiterung.
    Notes: Summary Muscle fibres of the red and slow contracting soleus of rat, rabbit and cat and of the red however fast contracting thyreoarytenoid of rabbit are compared with different fibre types in the anterior tibial muscle of rat and in the gastrocnemius of rabbit and cat. With respect to fibre types soleus and thyreoarytenoid (including m. vocalis) are homogeneous and both being rich in mitochondria. The fast thyreoarytenoid shows a narrow Z-line (50–60 nm) and a well developed sarcoplasmic reticulum. The pattern of reticulum and mitochondria resembles more that of heart muscle cells than of skeletal muscle fibres. Like many slow contracting muscles of different animals the soleus fibres display a wide Z-line (100–120 nm), few triads, little reticulum and irregularly shaped areas of myofilaments instead of fibrils. In that soleus fibres equal fibres of type C (rich in mitochondria) in a corresponding heterogeneous muscle, whereas intermediate (type B) fibres reveal narrow Z-lines (50–70 nm), isodiametrically shaped myofibrils and more triads than C-fibres. Therefore it is far more likely that the slow motor units of a mixed muscle consist of C-fibres than of B-fibres. This is at variance with the histochemical designation of soleus fibres as type B and thyreoarytenoid fibres as type C. In some muscles in C-fibres the sarcomeres are longer than in B-(and A-)fibres. In the anterior tibial muscle of rat this difference is 8.5% at a mean sarcomere length of 2.6 μm, and disappears at a mean length of 2.8 μm, probably due to the steeper slope of the length tension diagram at rest. Since the isometric extratension in a tetanus is highest at 120% resting length (corresponding to about 2.7 μm sarcomere length), the force of C-fibres exceeds that of B-fibres at 2.6 μm but not at 2.8 μm sarcomere length. Red and white muscle differ with respect to vascularisation. The relation between the densities of capillaries in soleus and gastrocnemius of cat is 2.7∶:1 and equals the relation between the blood flows through these muscles during rest and maximum vasodilatation.
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  • 43
    ISSN: 1432-0878
    Keywords: Dentine ; Bone ; Nucleation ; Collagen structure ; Collagen mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Von Ultradünnschnitten gefriergetrockneten, neugebildeten Dentins der Rattenschneidezähne und von glutaraldehydfixierten Proben der Compacta eines 10 Monate alten Kindes wurden — über Fokusreihen — Aufnahmen bei 20000∶1 und 40000∶1 angefertigt. Die gut fokussierten Aufnahmen wurden auf 200000∶1 bis 600000∶1 nachvergrößert; die Ausbildung der Ca-Phosphatkeime wurde in den beiden Zonen (“hole zone” und „overlapping zone”) der Kollagen-64 nm-Periode beschrieben. Ferner wurden die Abstände zwischen den punktartigen Keimen in den Ca-Phosphat-Nadeln und -Ketten beider Zonen vermessen und der Wahrscheinlichkeitsbereich für die Anzahl der Keime pro Zone (und damit pro Makroperiode) bestimmt. Die Punktkeimabstände lagen im Bereich von 4,0–8,5 nm und die Seitenabstände zwischen dicht benachbarten Ca-Phosphat-Nadeln im Bereich von 4,6–8,0 nm (vgl. Fig. 6). Bei Einsetzung der möglichen Fehlerbeträge unserer Bestimmungen (Anzahl der Keime pro Zone) können sich in der “overlapping zone”3–5 und in der “hole zone”6–8 Keime bilden. Diese Ergebnisse setzten wir in Beziehung: a) zur Anzahl der Querstreifen pro 64 nm-Periode im Kollagen, b) zu den von uns vermessenen Abständen zwischen diesen Querstreifen und c) zu den durch erste Sequenzanalysen erhaltenen Ergebnissen über die direkte Nachbarschaft von polaren, bindungsfähigen Aminosäuren im Kollagen. Es fand sich eine gute Übereinstimmung zwischen unseren Ergebnissen bzw. Schlußfolgerungen und den bisher vorliegenden Bestimmungen am Kollagen.
    Notes: Summary The best focussed members of a through focus series of electron micrographs of ultra-thin sections of freeze-dried forming rat incisor dentine and glutaraldehyde-fixed 10 months old human femoral cortex were selected for measurements. The original micrographs were prepared at magnifications of x20000 or x40000 and were photographically enlarged to a magnification from x200000 to x600000. The number of dot-like calcium phosphate nuclei per “hole zone” and per “overlapping zone” of the 64 nm collagen macro-period was determined; we found a range of 6–8 nuclei per “hole zone” and 3–5 nuclei per “overlapping zone”. Thus a total of 9–13 nuclei per 64 nm macro-period was found; this is in agreement with the total number of cross bandings per macro-period reported by previous authors. The distances between neighbouring dot-like calcium phosphate nuclei were measured and found to lie in the range of 4.0 to 8.5 nm, which is the range in which most of the distances between the collagen cross-bandings appear. The distances between close, parallel calcium phosphate rows within the collagen fibres were found to lie in the range 4.6–8.0 nm which seems to be a good deal shorter than the distances between the typical microholes of the Hodge-Petruska collagen model. Our results and ideas concerning the “active sites” of nucleation also are in agreement with previous amino acid sequence analyses in respect of the occurrence of neighbouring polar amino acids which would be free to bind ions.
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  • 44
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    Cell & tissue research 121 (1971), S. 153-170 
    ISSN: 1432-0878
    Keywords: Neutrophilic myelocyte ; Human bone marrow ; Secondary granulogenesis ; Phase contrast microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developmental changes in the neutrophilic myelocyte from normal human bone marrow have been analyzed by means of phase contrast and electron microscopy. This developmental stage is characterized principally by the elaboration of secondary (specific) granules. In addition, there is a modest decrease in cell size, a decrease in the number and mean size of primary (azurophil) granules, a decrease in the number of polysomes, free ribosomes and mitochondria, a depletion of rough endoplasmic reticulum, an increase in cytoplasmic glycogen, an increase in chromatin aggregations and a loss of nucleoli, and the formation of a markedly indented nucleus. The myelocyte stage has been subdivided into three arbitrary phases based upon morphological and functional characteristics which relate to the onset, active production and cessation of secondary granulogenesis.
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  • 45
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    Cell & tissue research 122 (1971), S. 1-14 
    ISSN: 1432-0878
    Keywords: Amnion ; Human amniotic plaques ; Fetal membranes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of amniotic and amniotic-plaque epithelia has been studied from normal term pregnancies. The columnar/cuboidal amniotic epithelial cells usually have apical or central nuclei, some free ribosomes, patches of granular endoplasmic reticulum, juxtanuclear Golgi complexes, rod-shaped mitochondria, lipid droplets and some glycogen granules. They have short, blunt microvilli which frequently branch and bathe in the amniotic fluid. The lateral plasma membranes enclose tortuous intercellular spaces which are always interrupted by variously folded processes and desmosomes. The epithelial cells rest on a basal lamina and exhibit highly folded basal processes. The amniotic epithelial cells are neither distinctly Golgi and fibrillar types nor “light” and “dark” in appearance. Amnion from near the umbilical cord contains many microscopic and several large plaques. Similar structures are not found on the reflected amnion. The microscopic plaques are whitish and translucent, whereas the large ones are opaque. The large plaques vary between 1–3 mm in diameter, and are over 15 cell layers thick. Each large plaque has a main central region and edges continuous with either the microscopic plaque or the simple amniotic epithelium. The main region shows four zones, namely, stratum basale, stratum spinosum, stratum granulosum and stratum corneum. Such zones are not distinct at the edges. The fine structure of basal cells compares with the amniotic epithelial cells, but the cells of spinosum and granulosum layers possess variable amounts of tonofibrils, keratohyalin granules, free ribosomes and other cytoplasmic organelles and inclusions. The corneum cells are keratinized and are frequently separated by intercellular spaces. They slough into the amniotic cavity singly or as a sheet, and contribute towards the composition of the amniotic fluid. The plaques are of amniotic origin, and are not formed by adhesion of either squamous cells or fetal skin cells (masses of keratinized squames). The present observations suggest that the occurrence of amniotic plaques is normal. The presence of plaques may not be necessarily associated with fetal abnormality. However, increase in numbers of plaques may be caused by conditions of fluid imbalance. The homology and significance of plaques in eutherian mammals have been discussed.
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  • 46
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    Cell & tissue research 113 (1971), S. 311-321 
    ISSN: 1432-0878
    Keywords: Ultimobranchial body ; Calcitonin ; Turtle ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultimobranchial body of fresh-water turtles,Pseudemys scripta andChrysemys picta, ultrastructurally and histochemically resembles the gland of other vertebrate groups and the homologous thyroid parafollicular cells of mammals. Characteristic features of all of these tissues are secretory granules measuring approximately 150–250 mμ, a distended endoplasmic reticulum, prominent Golgi regions and large numbers of free ribosomes. Unusual features of the turtle ultimobranchial body are an abundance of large cytoplasmic bodies measuring 800–1000 mμ and a dense, homogenous material within the lumina of the ultimobranchial follicles. The large cytoplasmic bodies usually occur near the luminal portion of the cells and are of similar electron density to the luminal contents, suggesting a possible functional relationship of these two glandular components.
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  • 47
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    Cell & tissue research 113 (1971), S. 558-563 
    ISSN: 1432-0878
    Keywords: Pterin layer ; Pigmentation ; Dermis ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the pterin layer was investigated in both wild type Rana pipiens and Rana pipiens homozygous for the speckle mutant gene. No difference in morphology of the layer was noted between the wild type and mutant. The layer lines the outer surface of the stratum compactum of the dermis and separates this stratum from the stratum spongiosum. The pterin layer consists of extra-cellular material and contains membrane-bounded granules filled with fine spicules. Many of the spicules are somewhat similar in appearance to the initial calcification loci present in developing membrane bone. The layer first appears in the tadpole at approximately stage 14 (Taylor and Kollros, 1946); subsequent developmental stages are described.
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  • 48
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    Cell & tissue research 114 (1971), S. 301-308 
    ISSN: 1432-0878
    Keywords: Freeze Fracture ; Microvasculature (chick) ; Ground substance ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tissues of the young chick and chick embryo were prepared in a relatively unaltered condition by the freeze-fracture technique. The ultrastructure of the microvasculature and surrounding interstitial region is compared with that seen in conventional thin-sectioned material. In the undifferentiated vessels of the 3-day chick embryo, no distinct basement lamina can be distinguished in either type of preparation. In the 3-week chick, a continuous basement lamina is present beneath the endothelium only in chemically fixed and sectioned tissue; it cannot be distinguished from the remaining interstitial substance in freeze-fracture preparations. Blood-tissue exchange may depend on permeability characteristics of the entire interstitial region rather than on the basement lamina alone.
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  • 49
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    Cell & tissue research 115 (1971), S. 1-16 
    ISSN: 1432-0878
    Keywords: Iris ; Rabbit ; Pinocytosis ; Enzymes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary On the basis of the occurrence, at the light microscopic level, of alkaline and acid phosphatases, the pigment epithelium covering the posterior surface of the iris in the albino rabbit can be divided into two zones not previously described, viz. a central zone close to the pupil, approximately corresponding to the area occupied by the iridic sphincter muscle, and a peripheral zone extending to the ciliary body. The central zone which is in intimate relation with the lens was found to have a high content of both phosphatases. At the fine structural level it exhibits a marked pinocytotic activity in the epithelium at the interdigitations between adjacent cells. Electron microscopy revealed that acid phosphatase is localized to the walls of the pinocytotic vesicles. Alkaline phosphatase is in evidence at the surface membrane folds and at microvillous processes between the epithelial cells and the adjoining muscle cells. Unlike the distribution of the acid phosphatase, that of the alkaline phosphatase does not differ fundamentally in the two zones at the fine structural level. In a series of dehydrogenases studied, staining with a view to succinic-, isocitric- and glucose-6-phosphate dehydrogenases revealed an evenly distributed content of enzyme throughout the epithelium. As to the lactic- and β-hydroxybutyric dehydrogenases, contents seem to be lower in the pupillary than in the peripheral zone.
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  • 50
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    Cell & tissue research 115 (1971), S. 396-415 
    ISSN: 1432-0878
    Keywords: Human pineal organ ; Development ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This investigation is concerned with pineal organs of human embryos 60 to 150 days old. At every stage central nerve fibres enter the pineal organ by way of the habenular commissure, but are restricted to the pineal's proximal part. On about the 60th day of the development the sympathetic nervus conarii grows into the distal pole of the pineal organ from a dorso-caudal direction and plays the predominant part in the innervation of the pineal organ. After penetrating, it soon branches out and forms a network in the pineal tissue. Much later, not until the 5th embryonic month, sympathetic nerves appear accompanying the supplying vessels in the perivascular spaces. After a short time these nerves pierce the outer limiting basement membrane and penetrate the parenchyma. Towards the end of the 5th embryonic month the axons of the sympathetic nerves form varicosities containing clear and dense core vesicles. At this point large amounts of laminated granules appear primarily in cell processes, probably of pinealocytes. Isolated granules also occur in the varicosities of axons. The granules encountered here are most likely secretory granules.
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  • 51
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    Cell & tissue research 116 (1971), S. 136-150 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex difference ; ACTH ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Nebennierenrinde von 178 Sprague-Dawley-Ratten wurde elektronenmikroskopisch von der 1.–12. Lebenswoche unter Normalbedingungen sowie nach s.c. Injektion von 3 IE ACTH/100 g Körpergewicht innerhalb von 2 min — 24 Std untersucht. Ab der 5. Lebenswoche unterscheiden sich die Nebennieren von Weibchen im Bereich der äußeren Zona fasciculata durch Kernvergrößerung, größere Mitochondrien und kleindisperse Liposomen von denen der Männchen. Zyklusbedingte Schwankungen in der Ultrastruktur der weiblichen Nebennierenrinde bestehen nicht. Nach ACTH-Applikation nähert sich das Nebennierenbild des Männchen innerhalb von 30 min dem des unbehandelten Weibchens. Außerdem kommt es bei beiden Geschlechtern durch ACTH zu einer Dispersion und Reduktion der Liposomen, Vergrößerung des Golgiapparates und der Zellkerne, Ausweitung des endoplasmatischen Retikulums und Vermehrung der Mikrovilli. Der Geschlechtsdimorphismus wird funktionell erklärt.
    Notes: Summary 178 Sprague-Dawley-rats were studied by electron microscopy from the 1st to the 12th week of life under normal conditions and after s. c. injection of 3 I. U. ACTH/100 gbodyweight from 2 min to 24 hours. Beginning with the 5th week of life females differ from males by small dispersed liposomes and enlarged nuclei and mitochondria in the outer z. fasciculata. There is no change in the ultrastructure of the female adrenal cortex depending on the sexual cycle. After application of ACTH the adrenal cortex of males assimilates to the untreated females within 30 min. After ACTH-application both sexes show dispersion and reduction of liposomes, dilation of endoplasmatic reticulum, increasement of microvilli and enlargement of the Golgi apparatus. The sex-dimorphism is interpreted by functional differences.
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  • 52
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    Cell & tissue research 119 (1971), S. 1-20 
    ISSN: 1432-0878
    Keywords: Human testis ; Gonocyte ; Spermatogonium ; Germ cell degeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic examination of the human fetal testis between 10 and 20 weeks gestation reveals the presence of two distinct cell types within the tubules: Sertoli cells and germ cells. The latter are distinguished by their spherical shape, smooth nuclear membranes, globular mitochondria and paucity of cytoplasmic organelles. The gonocytes, or primitive germ cells, occur as single cells in the central portions of the tubules. Their chromatin is finely granular and evenly dispersed. Nucleoli are centrally placed and of uniform electron density. Various stages in the migration of gonocytes to the tubular periphery are indicated by the extension of cytoplasmic processes toward the basal lamina. Bands of microtubules are present within the processes. Spermatogonia are arranged in pairs and groups at the tubular periphery. They lack the nucleolar and mitochondrial characteristics of adult spermatogonia. Except for slight changes in chromatin density and nucleolar structure, the fetal spermatogonia retain the ultrastructural characteristics of gonocytes. Intercellular bridges connect adjacent spermatogonia. Degeneration affecting large numbers of germ cells, but primarily gonocytes, begins with nuclear infolding and chromatin condensation and eventually involves both nuclear and cytoplasmic structures. The degenerated cells are removed by phagocytosis by adjacent Sertoli cells. Large phagosomes are present in the cytoplasm of many of the Sertoli cells.
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  • 53
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    Cell & tissue research 117 (1971), S. 139-154 
    ISSN: 1432-0878
    Keywords: Receptor cells ; Amines ; Lumbricus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Receptor cells in the epithelium and the basiepithelial nerve net of the prostomium of Lumbricus terrestris were investigated with electron microscope with special regard to the presence of monoamines. The receptor cells are found in groups of about 40 intermingled with supportive cells. After pretreatment with α-methyl-noradrenaline and fixation with potassium permanganate a few receptor cells in each group and some nerve fibres in the basiepithelial nerve net contain small granular vesicles (about400 Å) characteristic for monoaminergic neurons. The distribution and relative number of these receptor cells and nerve fibres coincide well with previous reports on fluorescent receptor cells and varicose fibres. That the monoamine-storing small granular vesicles not are visualized until pretreatment with α-methyl-noradrenaline is in accordance with recent microspectrofluorometric analysis, which shows that dopamine is the only primary monoamine present in the epithelium. In the epithelium there are occasional receptor cells and nerve fibres containing large vesicles (1000–1800 Å) which resemble the neurosecretory vesicles in the central nervous system. Photoreceptor cells having an intracellular cavity with microvilli and cilia have infrequently been observed at the base of the epithelium. No synapses on the mucous cells have been noticed. Nor have any synaptic specializations been observed in the basiepithelial nerve net. The morphological conditions necessary for the existence of possible axo-axonal synapses are briefly discussed.
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  • 54
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    Cell & tissue research 119 (1971), S. 483-514 
    ISSN: 1432-0878
    Keywords: Hermaphroditic Gonad ; Gastropoda ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In den Spitzenbereichen der Zwittergonadenacini fertiler Tiere der Pulmonatenspezies Planorbarius corneus sind drei Zelltypen stets gleichzeitig anzutreffen: Oocyten, Spermatiden und Begleitzellen. Die Abgrenzung der Acinusspitze gegen das interacinäre Gewebe hin bildet die Basalmembran des wandständigen Begleitzellepithels. Die Oocyten werden follikelartig von den ineinander verzahnten und durch Desmosomen verknüpften Begleitzellen umgeben. Nur in der Acinuskuppe liegen sie der hier stark verdickten Basalmembran unmittelbar auf. Die Spermatiden sitzen nur mit ihrem anterioren Zellpol den Begleitzellen apikal auf und sind durch Desmosomen mit ihnen verknüpft. Veränderungen der Ultrastruktur der Spermatiden während der Spermiohistogenese werden an drei gegeneinander abgrenzbaren Spermiohistogenesestadien aufgezeigt. Dabei finden die Kernstruktur, das Auftreten von Tubulikörpern und das Abstreifen des Restplasmas vom Mittelstück besondere Beachtung. Den recht uneinheitlich strukturierten Begleitzellen kommen für Oocyten und Spermatiden Ernährungs- und Transportfunktionen zu. Sie phagocytieren überfällige Geschlechtszellen. Es können jedoch trotz ihrer heteromorphen Struktur keine prinzipiell verschiedenen Begleitzelltypen mit jeweils nur einer spezifischen Funktion unterschieden werden. Das in früheren lichtmikroskopischen Arbeiten als Begleitzellprodukt beschriebene „Kinoplasma“ erweist sich als kernwärts wanderndes Restplasma der Spermatiden.
    Notes: Summary Three species of cells always coexist in the tips of hermaphroditic gonad-acini of fertile Planorbarius corneus: oocytes, spermatids and auxiliary cells. The basement membrane of the auxiliary cell epithelium separates the acinus tips from the interacinary tissue. Like follicles the oocytes are enclosed by interlocked and desmosomically attached auxiliary cells. Only in the utmost tips of the acinus the oocytes are in direct contact with the here dilated basement membrane. The spermatids are attached to the auxiliary cells only with their anterior cell-pole and connected with these by desmosomes. Alterations of the spermatid-ultrastructure during the spermiohistogenesis can be studied in three separate stages of the spermiohistogenesis. Particular attention is given to the nuclear structure, the tubular bodies and the shedding of residual plasma from the middle-piece. The rather irregularly structured cells serve oocytes and spermatids as mediators for nutrition and transport. Occasionally occurs phagocytosis of germ-cells. Basically, even though their structures vary, auxiliary cells are not restricted to one specific function. The “Kinoplasma”-described in previous light microscopic studies as a product of the auxiliary cells, proves to be spermatidic residual plasma moving towards the nucleus.
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  • 55
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    Cell & tissue research 120 (1971), S. 137-150 
    ISSN: 1432-0878
    Keywords: Umbilical vessels ; Guinea-pig ; Innervation ; Intermuscular contacts ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Umbilical vessels of guinea-pig fetuses were studied shortly before birth. In all umbilical cords investigated an innervation of the umbilical vessels is lacking. The intrafetal parts of the umbilical vessels on the other hand are richly innervated. A marked difference in the amount of nerve fibres and the pattern of innervation is found between artery and vein. The artery is supplied by a dense nerve plexus which spins around the media and which originates from nerve bundles within the outer adventitial layers. The comparatively scanty innervation of the vein exhibits a more coarsely meshed net pattern. The nerve bundles in the vein exhibit a close affinity to the vasa vasorum. Number and type of the close contacts between the muscle cells are different in the various sections of the umbilical vessels. Similar to the distribution of nerves they are almost absent in the vessels of the umbilical cord, numerously, however, in the intrafetal parts. Contrary to the innervation, the close contacts in the vein are developed more numerously and more broadly than in the corresponding artery.
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  • 56
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    Cell & tissue research 120 (1971), S. 386-400 
    ISSN: 1432-0878
    Keywords: Nervous System ; Carcinus maenas ; Cerebral ganglion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organization of the cerebral ganglion of the shore crab Carcinus maenas, is investigated by conventional histological and electronmicroscopic techniques. This study forms part of a comprehensive survey of the blood-brain interface, particularly interesting in this group, as decapod Crustacea are unusual among invertebrates in possessing an intracerebral blood supply. Apart from the intracerebral blood vessels, tissue organization is closely similar to that observed in insect central neural ganglia. The ganglion is surrounded by the neural lamella, an acellular connective tissue sheath, probably containing mucopolysaccharide and collagen. A layer of specialised glia, the perineurium, immediately underlies the neural lamella, and appears to contribute to its formation. Large glia occupying a conspicuous cortical zone below the perineurium may be involved in glycogen metabolism and storage. Further morphologically distinct glial types are observed associated with neurones and blood vessels, but all neuroglia within the ganglion are probably of common origin. Neurone cell bodies are generally situated peripherally in groups, and send axons into neuropil (synaptic) areas in the ganglion core. Large lacunae in the cortical region and narrower 20 nm clefts deeper in the ganglion, constitute the interstitial space, and contain deposits of fibrillar material. Possible physiological implications are discussed.
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  • 57
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    Cell & tissue research 120 (1971), S. 401-419 
    ISSN: 1432-0878
    Keywords: Nervous System ; Carcinus maenas ; Cerebral ganglion ; Intracerebral capillaries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the cerebral ganglion of the shore crab, Carcinus maenas, is investigated by conventional electron miscroscope techniques, with particular emphasis on the relation of intracerebral blood vessels to other elements in the brain. The ganglion is permeated by a continuous network of channels which may be interpreted as invaginations of the ganglion surface. The afferent vessel (cerebral artery) is of mesodermal origin, but apparently terminates as an open-ended vessel soon after entering the brain, where it runs within the invaginated channels. The greater part of the cerebral vasculature, therefore, has no mesodermal endothelial lining. Tissue components in the diffusion path between blood and brain which could conceivably restrict diffusion, are the thick glial basement membrane, junctions between perivascular and between interstitial glia, and polymeric material in the extracellular space. However, apart from a barrier to large colloidal particles at the basement membrane, the present EM observations do not decisively pinpoint sites of diffusional restriction, nor can they be interpreted as evidence that such restriction exists.
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  • 58
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    Cell & tissue research 120 (1971), S. 463-487 
    ISSN: 1432-0878
    Keywords: Cardiogenesis ; Cell Junctions ; Permeability ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Studies of cardiogenesis in the chick embryo focus attention upon the intercellular junctions of epicardial, myocardial, and endocardial cells, and the role they play in diffusion across the cardiac wall. Cell membranes of apposed epicardial cells approach as close together as 40 Å; those of the endocardium additionally form focal tight junctions. In the myocardium focal tight junctions are restricted to the apposed membranes of the superficial layer of cells. The majority of close appositions in all parts of the myocardium are 40 Å gap junctions. Desmosomes and fascia adherens are distributed throughout the myocardium. Diffusion of horseradish peroxidase through the epicardium and endocardium occurs primarily through the intercellular junctions. The width of the cleft between cells, 200–300 Å, also permits the diffusion between cells of the larger ferritin particles. Pinocytotic activity, responsible for ferritin transfer across mesothelial and endothelial cells in the adult, is not significant. Tracers injected into the pericardial cavity or vasculature can be observed passing through the heart in the direction of their respective diffusion gradients. Unlike the apical junctions of epithelial cells, to which they have been compared, membrane specializations of the superficial myocytes do not form a seal separating the pericardial cavity, or subepicardial space, from the extracellular spaces of the myocardium.
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  • 59
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    Cell & tissue research 113 (1971), S. 553-557 
    ISSN: 1432-0878
    Keywords: Albino rat ; Striatal neurons ; Endoplasmic reticulum ; Dark cisternal fields ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei der elektronenmikroskopischen Untersuchung des Striatums einer Ratte wurden im Perikaryon einiger Neurone eigentümliche parallele Anordnungen von membranbegrenzten Zisternen gefunden, welche durch eine auffallend dichte cytoplasmatische Matrix voneinander getrennt waren. Ein mit dieser Beobachtung völlig übereinstimmender Befund ist unlängst von anderer Seite an Nervenzellen des Nucleus entopeduncularis und der orbitofrontalen Großhirnrinde der Katze erhoben worden. Bei den „dunklen Zisternenfeldern“ dürfte es sich um Bereiche des endoplasmatischen Retikulums handeln, die sich in einem besonderen Funktionszustand befinden. Sie kommen wahrscheinlich schon normalerweise bei verschiedenen Tierarten in bestimmten Regionen des ZNS vor.
    Notes: Summary The electron microscopic study of a rat's striatum has revealed peculiar parallel arrays of membrane-bound cisternae with a strikingly dense intercisternal cytoplasmic matrix in the perikarya of a few neurons. The finding corresponds exactly to the unique lamellar configurations recently described in nerve cells of the entopeduncular nucleus and orbitofrontal cortex of the cat. These “dark cisternal fields” are regarded as distinct districts of the endoplasmic reticulum in a special functional state. They seem to occur normally in certain regions of the CNS in different animal species.
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    Cell & tissue research 114 (1971), S. 271-280 
    ISSN: 1432-0878
    Keywords: Thymus ; Rat ; Involution ; Reticulum-Cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Entodermale Thymus-Retikulumzellen neugeborener Wistar-Ratten enthalten häufig helle Vesikel mit enger räumlicher Beziehung zum Golgi-Apparat. Bei 13 Monate alten Ratten fehlen diese Vesikel. 2. Die Tatsache, daß die Häufigkeit heller Vesikel mit fortschreitendem Lebensalter abnimmt, findet ihre Parallele in der von anderer Seite getroffenen Feststellung, daß die Bildung eines humoralen Faktors im Thymus im Laufe der Zeit eingeschränkt wird. 3. Diese Koinzidenz läßt an die Möglichkeit denken, die hellen Vesikel könnten ein morphologisches Äquivalent der Bildung eines Thymuswirkstoffes sein. 4. In entodermalen Thymus-Retikulumzellen 13 Monate alter Ratten finden sich große Vakuolen mit granulärem Inhalt. Ihre Bildung beginnt schon vor der Thymusinvolution. Sie entstehen wahrscheinlich durch Phagozytose oder Aufnahme zelleigenen Materials, das nicht weiter abbaufähig ist. 5. Da diese Einschlüsse mit fortgesetzem Alter an Zahl und Größe zunehmen, scheinen sie als Ausdruck einer Beeinträchtigung der Stoffwechselvorgänge im Zytoplasma ein erstes morphologisch faßbares Symptom der frühzeitigen physiologischen Involution des Thymus zu sein.
    Notes: Summary 1. Entodermal reticulum cells of new born Wistar rats frequently contain clear vesicles with close connection to the Golgifield. These vesicles do not occur in reticulum cells of 13 months old rats. 2. The frequency of these clear vesicles decreases with advancing age obviously in the same way as the production of a humoral thymic factor reported by several investigators. 3. This observation agrees with the hypothesis that the clear vesicles are the morphological equivalent of the production of a humoral thymus factor. 4. Entodermal reticulum cells of 13 months old Wistar rats contain large vacuoles filled with electron dense, granulated materials. The formation of these vacuoles starts already before the beginning of the thymus involution. Possibly they are produced by phagocytosis or necrobiosis and contain deposits of material that cannot undergo further degradation. 5. The increase of these vacuoles in number and size with advancing age may be considered as equivalent of the deterioration of metabolism responsible for early involution of the thymus.
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    Cell & tissue research 117 (1971), S. 394-418 
    ISSN: 1432-0878
    Keywords: Portal Vein ; Innervation ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die V. portae der weißen Ratte wurde licht-, fluoreszenz- und elektronenmikroskopisch auf ihre Innervation untersucht. 1. Paraldehydbedampfte Venenpräparate und Häutchenpräparate der gesamten Wandung (Falcksche Fluoreszenzmethode) lassen einen überwiegend längsorientierten äuβeren Nervenplexus erkennen, der den äußersten Muskelzellen aufliegt. Er ist leberseitig weitmaschig, darmseitig sehr engmaschig. Ein subendothelial gelegener innerer Plexus ist vorwiegend zirkulär orientiert. Er entspringt dem äußeren Plexus der darmseitigen Gefäßpartien. 2. Der Nachweis der Acethylcholinesterase (Gomori-Methode) bringt lichtmikroskopisch einige Nervenbündel in der bindegewebigen Adventitia zur Darstellung. Im übrigen findet sich die Aktivität des Enzyms nur in den interzellulären Spalten der Muskelschicht. Der elektronenmikroskopische Nachweis der Acethylcholinesterase (Karnovsky-Methode) läßt aber erkennen, daß sich die Enzymaktivität auf die Muskelzellmembranen beschränkt. 3. Die elektronenmikroskopische Untersuchung bestätigt den fluoreszenzmikroskopischen Befund. a) Lebernah finden sich nur vereinzelte Axonbündel, die der äußeren Muskellage aufgelagert sind. Die Einzelaxone sind vollständig von den Schwannschen Zellen umgeben. Nur wenige, den Muskelzellen benachbarte Axone enthalten agranuläre Vesikel. Sehr selten sind Ausfaltungen der vesikelhaltigen Axone zu sehen, deren Abstand zur Muskelzelle aber immer noch 1000–2000 Å beträgt. b) Auf über eintausend Dünnschnitten wurde kein Axon innerhalb der dicken Muskelschicht gefunden. c) Subendothelial verlaufende Axone (innerer Plexus) sind teilweise oder völlig aus den Schwannschen Zellen ausgefaltet. Sie sind dicht besetzt mit leeren Vesikeln (300–650 Å) und enthalten wenige kernhaltige Vesikel in der Größenordnung 800–1600 Å. Synaptische Endigungen werden nicht beobachtet. d) Eine dichte Häufung vesikelhaltiger Axone, die teils völlig, teils nur an der muskelzellnahen Seite aus den Schwannschen Zellen ausgefaltet sind, finden sich am Übergang der V. mesenterica superior zum Pfortaderstamm, deren einschichtiger Muskellage angelagert. Von diesen Bündeln stammende kleinere Bündel und Einzelaxone ziehen zwischen den Muskelzellen hindurch und erreichen das Endothel. Typische Synapsen werden nicht beobachtet. Kein vesikelhaltiges Axon nähert sich mehr als 1000 Å den Muskelzellen. 4. Die ausgefalteten vesikelbesetzten Axone werden als vegetative Überträgerstrecken angesehen. Die Erregung der Effektorstrukturen durch Transmittersubstanzen wird im Zusammenhang mit der postmortalen autonomen Gefäßkontraktilität diskutiert.
    Notes: Summary The innervation of the portal vein of the white rat was examined with light-, fluorescence-, and electronmicroscopic techniques. The results are as follows: 1. Paraldehyde treated vein preparations (Falck's fluorescence method) demonstrate a predominantly longitudinally orientated external nerve plexus, being situated on the outermost muscle cells. Near the liver the nerve net is characterized by broad meshes, near the intestinal tract by narrow ones. The circular subendothelial inner plexus originates in the outer plexus of the intestinal vascular bed. 2. Nerve bundles in the fibrous adventitia were demonstrated with Gomori's Acethylcholinesterase method. In other respects, the enzyme activity was only observed in the intercellular spaces of the muscle layer. The electronmicroscopic demonstration of Acetylcholinesterase (Karnovsky's method) further showed that the enzyme activity is restricted to the muscle cell membrane. 3. The electronmicroscopic examination verified the results obtained with fluorescence microscopic techniques. a) In the proximity of the liver, only isolated nerve bundles occur on the outer muscle layer. The individual nerves are entirely surrounded by Schwann cells. Only a few of the axons in the vicinity to the muscle cell have agranular vesicles. Evaginations of the vesicular axons occur infrequently. Their distance from the muscle cell amounts to 1000–2000 Å. b) In more than one thousand thin sections, no axons were found inside the thick muscular layer. c) Subendothelial axons (inner plexus) are either partially or totally evaginated from the Schwann cells. They are densely filled with empty vesicles (350–650 Å) and contain a few dense core vesicles of 800–1600 Å in diameter. Synaptic endings were not observed. d) A dense collection of vesicle-containing axons, that were partially in their entirety and partially only from the muscle cell proximal side evaginated from the Schwann cells, were observed in the single muscle layer at the junction of the superior mesenteric and the portal vein. From these bundles, smaller bundles and individual axons pass between the muscle cells and reach the endothelium. Typical synapses were not observed. No vesiclecontaining axon was nearer than 1000 Å to the muscle cell. 4. Those axons possessing vesicles and being evaginated are considered to be vegetative conducting pathways. The excitation of the effector structures by transmitter substances is discussed in connection with the post mortem autonomic vascular contractility.
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    Cell & tissue research 117 (1971), S. 463-475 
    ISSN: 1432-0878
    Keywords: Bone marrow ; Leukocytes ; Electron microscopy ; Histochemistry ; Peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of peroxidase activity has been studied in the cells of normal human bone marrow using the diaminobenzidine peroxidase technique. Peroxidase activity has been localized within the primary (azurophil) granules of the neutrophilic series as well as in the cytoplasmic granules of eosinophils, basophils and monocytes. Peroxidase activity appears within the cisternal system (nuclear envelope, Golgi complex and rough endoplasmic reticulum) of these cells during the period of peroxidase-containing lysosome production. With the cessation of granulogenesis, peroxidase activity disappears from the cisternal system and does not reappear in subsequent developmental stages. In cells incubated in peroxide-free media, staining of granular components, but not of cisternae, is reduced. The inclusion of catalase in peroxide-free media eliminates all staining. This indicates that an endogenous peroxide is present within the cisternae and granules of these cell types.
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    Cell & tissue research 117 (1971), S. 516-525 
    ISSN: 1432-0878
    Keywords: Liver ; Chicken ; Prenatal development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the developing chicken liver has been reexamined on specimens fixed by perfusion with glutaraldehyde. This fixation technique gives a preservation of ultrastructural detail superior to that of earlier investigations. Among others the following observations may be pointed out: 1. Bile canaliculi with well-developed microvilli and adjacent tight junctions are present already at the 4-day-old stage and then remain essentially unchanged during development. 2. A subendothelial space of Disse is not present until about 16 days of incubation. 3. The Golgi apparatus does not assume its adult appearance until about 8 days of incubation. 4. Glycogen is first observed in the 6-day-old specimens and then continuously increases throughout development. Glycogen particles often accumulate in membranelimited bodies reminding of the glycogen-filled lysosomes found in a certain type of glycogenosis (Pompe's disease). 5. The mitochondria increase in size and number during development with a conspicuous change from rounded towards more rodshaped and elongated forms.
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    Cell & tissue research 117 (1971), S. 576-596 
    ISSN: 1432-0878
    Keywords: Median eye ; Frontal organs ; Crustacea ; Anostraca ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Mittelauge (MA) und das ventrale Frontalorgan (FO) von Artemia salina L. (erwachsene Tiere) wurden elektronenmikroskopisch untersucht. 1. Das MA ist ein inverses Becherauge. Ein Pigmentbecher aus zwei Pigmentzellen umschließt drei Sehzellgruppen. Die Sehzellen bilden verzweigte Rhabdome vom geschlossenen Typ. Ihr Zytoplasma enthält zahlreiche Vesikel, tubuläre Mitochondrien, kleine Golgiapparate, Mikrotubuli, variable multivesicular und lamellated bodies und Lipideinschlüsse, die von endoplasmatischem Retikulum spiralig umgeben werden. 2. Die Pigmentzellen enthalten dicht gepackte Pigmentkörner, einen gelappten Kern, Mitochondrien vom Cristatyp, wenig endoplasmatisches Retikulum, Mikrotubuli, lamellated und vesicular bodies. Gegenüber den rhahdombildenden Anteilen der Sehzellen ist ihre Zelloberfläche glatt, im übrigen bilden sie lange fingerförmige Ausstülpungen. 3. Artemia salina besitzt zwei Arten von Frontalorganen. Die „dorsalen PO“ sind möglicherweise neurosekretorische X-Organe. Das ventrale FO wird als Sehorgan gedeutet. Es besteht aus zwei Gruppen von Sehzellen ventral vom MA, die eigene Nervenfortsätze zum Protocerebrum senden. Die optische Achse ist der des ventralen Augenbechers entgegengesetzt. Zwischen MA und FO verläuft ein Nerv, der wahrscheinlich dem MA angehört. 4. Übereinstimmungen der Feinstruktur von MA, FO und den Retinulazellen der Komplexaugen betreffen insbesondere die Binnenstruktur der Rhabdommikrovilli und Äquivalente unterschiedlicher Funktionszustände (Hell-Dunkel-Adaptation) hinsichtlich der Ausbildung von perirhabdomalen Vakuolen und des Ausmaßes von pinocytotischen Vorgängen an der Basis der Rhabdome.
    Notes: Summary The median eye (MA) and the ventral frontal organ (FO) of Artemia salina L. (adult specimens) have been investigated with the electron microscope. 1. The MA is an inverse cup-shaped eye. A pigment cup, consisting of two pigment cells, surrounds three groups of photosensory cells, which form ramified rhabdoms of the closed type. Their cytoplasm contains numerous vesicles, tubular mitochondria, small Golgi fields, microtubules, variable multivesicular and lamellated bodies and lipid inclusions, which are surrounded by spirals of endoplasmic reticulum. 2. The pigment cells contain densely packed pigment granules, an indented nucleus, crested mitochondria, small amounts of endoplasmic reticulum, microtubules, lamellated and vesicular bodies. Opposite the rhabdomeric surface of the visual cells their cellular surface is smooth, otherwise it bears long fingershaped projections. 3. Artemia salina possesses two types of frontal organs. The “dorsal FOs” are possibly neurosecretory X-organs. The ventral FO is interpreted to represent a photosensory organ. It consists of two groups of sensory cells located ventrally of the MA, which possess own nerve-processes leading to the Protocerebrum. Their optical axis is opposite the one of the ventral eye cup. Between MA and FO a nerve occurs, which presumably belongs to the MA. 4. Considerable finestructural similarities between MA, PO and the retinula cells of the compound eyes exist as far as the internal structure of the rhabdomeric microvilli and the equivalents of different functional stages (Light-Dark-Adaption) are concerned, namely perirhabdomeric vacuoles and the degree of pinocytotic processes at the base of the rhabdoms.
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    Biopolymers 10 (1971), S. 1049-1057 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ultrastructural morphology and x-ray and electron diffraction of poly (Gly-Gly-Ala) have been studied. The polymer has two forms; the first, form I possesses a super-folded cross-β structure, long fibers of which show some twisting and intertwining. Form II precipitates in a less distinct fibrous form from aqueous solution. The x-ray diffraction and oriented electron diffraction data suggest that form II is a polyglycine II helix situated in a monoclinic cell with dimensions a = 8.86 Å, b = 22.0 Å, c = 9.42 Å, and β = 90°. Combined with the morphological evidence it appears likely that form II is also in an antiparallel superfolded array.
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    Biopolymers 10 (1971), S. 1099-1101 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A statistical mechanical model was developed for use in connection with the problem of preferential binding of solvent components to proteins and of conformational transition in water-organic solvent systems. The model is a statistical one for the conformational transition of globular proteins induced by the adsorption of solutes in the solution, considered as a nearest-neighbor problem in statistical mechanics. Although a few illustrative examples are given, the actual interpretations of the experimental data using this theory are reserved for a later paper.
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    Biopolymers 10 (1971), S. 1103-1103 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Biopolymers 10 (1971), S. 1121-1138 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept and representation of a logical tree as defined in computer science is applied to obtain a suitable representation of protein molecules in computer programs which handle or calculate atomic coordinates of protein molecules. On the basis of this analysis and of the analysis of the calculation and modification of the structure of a protein from bond lengths, bond angles, and dihedral angles, which is reproduced in an appendix, program modules which accomplish the various required computations are described. Three such modules are given in Iverson notation; in fact, it is hoped that this article will serve as a reasonably complete basis for the preparation of machine programs by moderately proficient programmers.
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    Biopolymers 10 (1971), S. 1207-1212 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism spectrum obtained from a dilute aqueous solution of poly (ala-gly-gly) resembles that described for charged polypeptides such as the salt form of poly glutamic acid. A similar spectrum is found for films cast from aqueous solution where x-ray studies reported elsewhere have indicated a poly-glycinc II conformation. Evidence is presented for a heat induced poly-glycine II to unordered state transition similar to that described for collagen. The interpretation of this, the first observation of the optical properties of a poly-amino acid in the poly glycine II conformation, is further rationalized on the basis of spectra obtained from a number of polypeptides whose conformation approaches that of a 31 helix.
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    Biopolymers 10 (1971), S. 1229-1242 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of cupric ion on the emission of tryptophan, tyrosine, and serum albumins is studied by emission spectroscopy and lifetime measurements. It is found that whenever cupric ion is bound to tryptophan or tyrosine, their emissions are quenched completely. The quenching may be due to an electron transfer mechanism. The fluorescence of complexes of cupric ions with serum albumins is partially quenched; this is because energy is transferred from tryptophan to the complexed cupric ions by a dipolar energy transfer mechanism. It is deduced from the present study that the tryptophan in the human serum albumin molecule is between 11 and 16 Å from the nearest eupric ion binding sites (assumed to be at the surface of the protein) and that one of the tryptophan in the bovine serum albumin molecule is very close to the cupric ion binding sites and the other is near the center of the bovine serum albumin molecule. It is also found that the deuterium solvent effect on serum albumin fluorescence is very small, and that the quenching of bovine serum albumin fluorescence at the N-F transition is the result of quenching of the fluorescence of both tryptophans. The phosphorescence lifetime apparatus, capable of measuring decay times of signals with intensities changing over a few orders of magnitude, and the ratio spectrofluorometer, both of which were constructed in this laboratory, are also described.
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    Biopolymers 10 (1971), S. 1253-1260 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The measurements were made for the volume and the sound velocity changes (ΔV and ΔU) on titrating the sodium salt of poly (S-carboxymethyl L-cysteine) with dilute HCl. For the reaction, —COO- + H+ → —COOH, ΔV per mole of H+ bound was + 12. 7 ml and +11. 4 ml in salt-free and 0. 2 M NaCl solutions, respectively. Corresponding ΔU was about -13 cm/sec in salt-free polymer solution where 11.5 mM carboxylate ion reacts with equimolar hydrogen ion. ΔV associated with the coil-to-β transition was found to be +2. 35 ml in H2O and +1. 90 ml in 0. 2 M NaCl per mole of amino acid residue, respectively. These values are larger than those obtained for the coil-to-helix transition of poly (L-glutamic acid). ΔU for the transition was about -30 cm/sec in salt-free solution of polymer concentration 0.0115 mole/liter. Possible sources of ΔV and ΔU for reaction; coil → β, are (1) the formation of void volume and (2) the changes in the extent of solvation in amide linkage and in side chain.
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    Biopolymers 10 (1971), S. 1317-1329 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding of three aromatic molecules to apomyoglobin has been investigated. In each case equilibrium dialysis studies and tryptophan fluorescence quenching studies indicate that a one to one complex has been formed. The fluorescence quenching studies further suggest that the binding of the aromatic molecules is at the heme site with possible involvement of the arginine CD3. Xenon, which is known to quench the fluorescence of aromatic hydrocarbons, is found to be bound to apomyoglobin-aromatic molecule complexes and quenches the emission of the aromatic molecule in the complexes. Oxygen quenches pyrene fluorescence in water solution but does not quench the pyrene fluorescence from the apomyoglobin-pyrene complex. This is explained by a slower rate of diffusion of oxygen to pyrene in the apomyoglobin-pyrene complex.
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    Biopolymers 10 (1971), S. 1365-1369 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rotor speed-dependent aggregation of T4 DNA in the analytical ultracentrifuge is studied in the presence of high pressure generated by compressed nitrogen gas in the cell. The extents of aggregation at various speeds are found to be practically the same in the presence and absence of pressure.
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    Biopolymers 10 (1971), S. 1331-1349 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The time-dependent theory developed in Part I is specialized to treat tetrameric hemoglobin, and the results of the theory for dimeric-and tetrameric hemoglobin are compared with data on the kinetics of the reactions of hemoglobin with carbon monoxide and oxygen at various salt concentrations for the case of large concentration of ligand relative to that of hemoglobin. The fit of the theoretical results to the data suggests that hemoglobin at a 2 M salt concentration is predominantly dimeric and that the tetramer should be taken as the functional unit to explain the kinetics of the reactions of normal hemoglobin. A relationship is established between the time-dependent theory arid Adair's Intermediate Compound Hypothesis (I.C.H.) for hemoglobin, as brought to its present state by Gibson and Roughton. A generalization (G.I.C.H.) of the I.C.H. is presented and is shown to be equivalent to the time-dependent theory in the limit of infinite ligand concentration. The I.C.H. is shown to be an excellent approximation to the centralized theory (G.I.C.H.) in this limit.
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    Biopolymers 10 (1971), S. 1421-1425 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 77
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    Biopolymers 10 (1971), S. 1427-1428 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Biopolymers 10 (1971), S. 1429-1454 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability of oligodesoxyribonucleotides of various chain lengths to form complexes has been compared with that of oligoribonucleotides. Four series of oligonucleotidcs were prepared and investigated, i.e., dCn at acid pH versus rCn, dAn and dTn versus. rAn and rUn at neutral pH. The results indicate that in dilute solution, the formation of complexes is greatly facilitated in the case of desoxyoligomers and occurs for shorter oligomere than in the corresponding ribooligomers. The spectrophotometric titration of deoxyribooligo C indicates the appearance of two pK values in the 4-5 pH region characteristic of the double-stranded form, which occurs for much shorter dCn than rCn. The circular dichroism (CD.) spectra of deoxycytidylies in dilute solution starting from the trimer are conservative, characteristic of the double-stranded helical form of poly C at acid pH. In contrast, the CD spectra of a series of corresponding ribo Cn, under identical conditions is of nonconservative character similar to that of the single-stranded form of poly C at neutral pH, but differs in the band position. This spectrum is called intermediate. Only at higher concentrations of oligonucleotidcs (i.e., 10-3Minstead of 10-4M) does the circular dichroism spectrum of longer ribocytidylics assume conservative character. Thermal denaturation of deoxycytidylces at acid pH are strongly dependent on chain length and concentration, its one would expect for a cooperative helix-coil transition. The circular dichroism spectra measured at different temperatures shows one isosbestic point. In dilute solution, the standard-state enthalpy change found was 5-6 kcal/mole for higher oligomers (dC7). These properties are all in agreement with a structural transition from the d-Cn double-stranded form to a coil for n 〉 3. Studies of dAn and dTn in solutions of high ionic strength at low temperature indicate that complex formation occurs already at the level of trimer and for high oligomers. Under identical conditions a complex between rAn and rUn is detected only for oligomers longer than the hexamer. The nature of the “intermediate” form of oligoribo C at acid pH and low temperature was investigated by sedimentation and circular dichroism. A model of rCn is proposed of linear molecules which are partially double-stranded and partially single-stranded, which probably are slowly rearranged by “slippage” into a regular-double-stranded helical form.
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  • 79
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The number average molecular weight, Mn, of low molecular weight dextran was determined through endgroup analysis, and the intrinsic, viscosities of these materials in aqueous solution were determined at 25°C. The ultrasonic velocities in their aqueous solutions were also measured at 25 and 45°C. As concerns the molecular weight dependence of the intrinsic viscosity, partial specific compressibility of solute and the hound water around the solute, the following results were obtained. (1) log [η]-log Mn and [η]/Mn0.5 - Mn0.5 plots were in accord with the Mark-Houwink and Stockmayer-Fix-man equations respectively for Mn 〉 2, 000, but these plots deviated from the equations for Mn 〈 2, 000. (2)The partial specific compressibility, β1°, of dextran is expressed by following equation for Mn 〈 2,000: β1° = 10-12 × (13.6 log Mn - 51.7) (cm2/dyne). In contrast, it, becomes the constant value, -- 7.3 × 10-12 cm2/dyne, for Mn 〉 2,000. (3) The amount of bound water of dextran calculated from the sound velocity measurement lakes constant value of 0.17 ml g for Mn 〉 2, 000, but the amount of hydration increase with decreasing molecular weight for Mn 〈 2,000. From these results, a dextran molecule in aqueous solution is expected to change its conformation from random coiling to uncoiling stretched form at the molecular weight of around 2, 000 or about 12 glucose units.
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  • 80
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    Biopolymers 10 (1971), S. 1559-1581 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical rotation studies were performed on five compounds containing two peptide groups. Four of the molecules were confined to restricted regions of conformational space by the presence of closed rings. Solvent and temperature were varied, and theoretical calculations were done for each compound covering the appropriate conformational space. The interpretation which results is qualitatively successful over the conformational regions covered by the compounds. Quantitative correlation between theory and experiment will require compounds of high rigidity.
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  • 81
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    Biopolymers 10 (1971), S. 1617-1623 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational energy maps have been calculated for α-D-mannuronic acid (1-4) α-L-guluronic acid and for α-L-guluronic acid (1-4) β-D-mannuronic acid. These have been used, together with maps previously calculated for the homomonomeric dimers, to estimate the characteristic ratios and Kuhn lengths of the alternating copolymer and of a stochastic copolymer similar in composition to that extracted from L. digitata.The results show that the alternating copolymer is less extended than either homopolymer. Kuhn lengths calculated for the stochastic copolymer agree well with experimental results on high ionic strength solutions of alginate isolated from L digitata.
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  • 82
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    Biopolymers 10 (1971), S. 1635-1648 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly-S-carboxyethyl-L-cysteine, a higher side-chain homolog of poly-S-carboxymethyl-L-cysteine, has been prepared from poly-S-carbobenzoxyethyl-L-cysteine with hydrogen bromide in chloroform or acetic acid. The polymer is found to be in the β-conformation of an antiparallel arrangement of polypeptide chains in solid films, both in acid and salt forms, when examined by infrared spectra. Aqueous solutions of t he polymer have been investigated by measurements of rotatory dispersion and circular dichroism as well as by infrared spectra in D2O. These properties show sharp changes around pH 5.5, as the pH of solution is varied. At higher ionization the polymer is randomly coiled, but at lower ionization it is in the β-conformation. Dependence of the rotatory properties upon polymer concentration as well as on ionic strength has been observed even at the lowest degree of ionization attained, and this has been attributed to the formation of intermolecular β-conformation in solutions. The β-structure is characterized by a negative circular dichroic band at 223 mμ and a positive dichroic band at a wavelength lower than 200 mμ, and furt her by a negative bo value, -140°. The pH-induced coil-β transition of the polymer is compared with that of poly-S-carboxymethl-L-cysteine.
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  • 83
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    Biopolymers 10 (1971), S. 1681-1699 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The specific heat, of rat tail tendon at various water contents was measured as a function of temperature. The resulting graphs showed peaks arising from the melting, near 50°C, of helical material in the collagen, and from the melting of absorbed water in the range -40°C to 0°C. The heat of melting of helical material was 11.7 cal per gram of dry tendon. Determination of the heat and temperature of fusion of the absorbed water allowed resolution of the water into four states in the case of tendon before denaturation, and three states after denaturation. The four states are (1) water not freezable on cooling to - 70°C, (2) freezable water with-both heat and temperature of fusion different from the values for ordinary water, (3) freezable water with the heat of fusion of ordinary water, but a different temperature of fusion, and (4) water not distinguished from ordinary water. The fourth state was absent in denatured tendon. The results are discussed in terms of increasing size of clusters of absorbed water molecules.
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  • 84
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    Biopolymers 10 (1971) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 85
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    Biopolymers 10 (1971), S. 1743-1757 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absorption and rotatory properties of acridine orange-poly-S-carboxymethyl-L-cysteine system in water and in 0.2 M NaCl have been measured at different pH and polymer-to-dye mixing ratios. The absorption spectra indicate that the dyes are bound to the polymer in dimeric or highly aggregated forms. At neutral pH where the polymer is randomly coiled, no optical activity is induced on the absorption bands of bound acridine orange. At acid pH where the polymer has the β-conformation, a pair of positive and negative circular dichroic bands occur at each of the absorption bands, centered around 458 and 261 mμ. The signs of those bands are opposite to those found for α-helical poly-L-glutamic acid. A model for the binding of dye to the β-form polymer is presented, in which dimeric dyes are attached to ionized carboxyl groups and slack one another to form linear arrays on both sides of an extended polypeptide chain. The observed circular dichroism spectra can be explained by the Tinoco's exciton mechanism, based on this model. Low molecular weight poly-S-carboxymethyl-L-cysteine induces quite a different circular dichroism on bound acridine orange.
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  • 86
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    Biopolymers 10 (1971), S. 1853-1863 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dicrosim (CD) spectra of complexes of DNA with ethidiun bromnide, profiavine, 9-aminoacridine and 4-etliyl-9-amino-acridine have been determined between 220 and 450 nm, the range lieing extended to 600 nm for ethidiufm bromide. The variation of the magnitude of the visible and near - ultraviolet CD spectra of ethidium bromide - DNA complexes with the amount of ligand bound (r) suggests a common binding position with profiavine. On the other hand, 4-ethyl-9-aminoacndine complexed to DNA shows CD spectra not distinguishable from those of 9-aminnoacnidmc in both the visible and ultraviolet. The interpretation of these results with respect to the stereochemistry of the DNA-ligand complexes is discussed.
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  • 87
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    Biopolymers 10 (1971), S. 1901-1924 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The various treatments of sedimentation equilibrium are compared on a theoretical and an experimental basis. Particular attention is paid to the polyelectrolyte nature of the problem and the choice of a neutral component. The effective density gradients of several cesium salts for DNA are measured. Two previous theories for the effective density gradient are shown to be equivalent, and the experimental values are interpreted with respect to these theories. It is clear t hat sedimentation equilibrium in a density gradient may be used for the determination of unambiguous molecular weights.
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  • 88
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    Biopolymers 10 (1971), S. 1949-1972 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The theory of friction-limited DNA unwinding is developed explicitly for moderate tind large perturbations. This extension of the earlier theory of the relaxation kinetics is necessary because of the complex nature of the rate limitation for small perturbations. The assumption of the theory that is violated under relaxation conditions is that base pairing reactions occurring at a constant local degree of twist of the strands are fast compared to the net unwinding of the molecule. However, these reactions that are slow for small perturbations have a large activation energy, and become faster than friction-limited un winding for large enough temperature jumps and sufficiently large DXA molecules. Thus only the rate for moderate and large perturbations is clearly limited by frictional resistance to turning the molecule in solution. The model used is a diffusional unwinding of the two strands, driven by the accompanying decrease in free energy. For large perturbations a numerical solution of the diffusion equation is required, since the diffusion coefficient is not constant. Two new parameters must be introduced into the equilibrium statistical theory to describe friction-limited unwinding kinetics. These are the force constant b, for winding up coil regions and the frictional coefficient per base pair βcfor rotating coil regions in solution. We find by fitting the theory to experiment that b = 1.8 × 10-13 ergs/ rad2- and βc = 3.5 × 10-21 erg see/base pair, both for DNA melted in alkali at 0.4.M Na + and ∼30 °C. The latter value is in agreement with predictions based on the viscosity of single stranded DNA in alkali. The quoted value of bcan be interpreted to mean that the number of conformational states of a nucleolide is reduced by an average factor of 1.55 when it is wound around another strand to the degree of twist in a double helix, but without forming a base pair.
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  • 89
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The properties of oligonucleotide helices of adeuylic- and uridylic acid oligomers have been investigated by measurements of hypo-and hyperchromieity. High ionic strengths favor the formation of triple helices. Thus, the double helix-coil transition can be studied (without interference by triple helices) only at low ionic-strength. A “phase diagram” is given representing the Tm-values of the various transitions at different ionic strengths for the system A(pA)17 + U(pU)17. Oligonucleolides of chain lengths 〈8 always form both double and triple helices at the nucleotide concentrations required for base pairing. For this reason the double helix-coil transition without coupling of the triple helix equilibrium can only be measured for chain lengths higher than 7. Melting curves corresponding to this transition have been determined for chain lengths 8, 9, 10, 11, 14 and 18 at different concentrations. An increase in nucleotide concentration leads to an increase in melting temperature. The shorter the chain length the lower the Tm-value and the broader the helix-coil transition. The experimental transition curves have been analysed according to a staggering zipper model with consideration of the stacking of the adeuylic acid single strands and the electrostatic repulsion of tlip phosphate charges on opposite strands. The temperature dependence of the nucleation parameter has been accounted for by a slacking factor x. The stacking factor expresses the magnitude of the stacking enthalpy. By curve fitting xwas computed to be 0.7, corresponding to a stacking enthalpy of about S kcal/mole. The model described allows the reproduction of the experimental transition curves with relatively high accuracy. In an appendix the thermodynamic parameters of the stacking equilibrium of poly A and of the helix-coil equilibria of poly A + poly U at neutral pH are calculated (ΔHA = -7.9 kcal/mole for the poly A stacking and ΔH12 = -10.9 kcal/mole for the formation of the double helix from the randomly coiled single strands). A formula for the configurational entropy of polymers derived by Flory on the basis of a liquid lattice model is adapted to calculate the stacking entropies of adenylic oligomers.
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  • 90
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    Biopolymers 10 (1971), S. 2049-2049 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
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    Biopolymers 10 (1971), S. 2071-2077 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The data on the band widths and band shapes of several DNA's at various concentrations in sedimentation equilibrium in a CsCl density gradient have recently become available. In the present report, these literature data are treated in the following manner: (1) based on a theory of isotope-substitution, calculations are made of the molecular weights at infinite dilution, and (2) to explain the concentration dependence of band widths and band shapes, a theory of charge and hydration is put forth, and it is shown that by retaining the terms involving the charge of the macromolecules, it is possible to account for most of the concentration dependence.
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  • 92
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    Biopolymers 10 (1971), S. 2083-2094 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of the unique and specific association of a given amino acid to its t-RNA is investigated by theoretical methods. Several possible schemes are proposed to explain specificity. The physical forces which act within these mechanisms are illustrated by the computer simulation of probable interactions between glycine and nucleotide bases and base pairs. It is demonstrated that glycine has direct and selective affinities for the nucleotide bases and that these interactions are principally determined by the polar groups. Energies have been calculated for the interaction of glycine with several base pairs. From these, the possibility that specificity arises through direct complexing of an amino acid with its anticodon is evaluated.
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  • 93
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    Biopolymers 10 (1971), S. 2147-2160 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Equations are developed to describe the shift in the temperature of the helix-coil transition when small molecules bind to nucleic acids. Included are high polymers, oligonucleotides, and oligomer-polymer interactions. The equations prescribe simple ways of plotting experimental data to evaluate transition and binding parameters.
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  • 94
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    Biopolymers 10 (1971), S. 2181-2197 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil transitions for poly-L-lysine (PL) were investigated by the methods of spectropolarimetry, viscometry and potentiometric titration in 0.2M NaCl at different temperatures as well as in 0.2MNaBr, 1MKCl, and in mixtures of 0.2MNaCl or NaBr with methanol at room temperature. The enthalpy and entropy differences between the helical and coillike states of uncharged PL molecules in 0.2.M NaCl were determined from the potentiometric titration curves. The cooperativity parameters σ for PL in different solvents were determined by two methods (from the sharpness of the transition and from the dependence of the intrinsic viscosity on the helical content in the transition region). In 0.2MNaCl σ has a value of (2.3 ± 0.5) × 10-4 and does not depend on temperature, i.e., the cooperativity of the helix-coil transition, as for PGA, is mainly of an entropy origin (the initiating of the helical region is accompanied by the entropy decrease ΔSi = -12 eu/mole of helical regions). A comparison of the obtained results for PGA and PL with the molecular theories of the helix-coil transitions shows that the role of dipole-dipole interactions of nonneighboring peptide groups is greatly overestimated in these theories, leading to a considerable enthalpy contribution to the free energy of initiating helical regions which is not observed in the experiment.
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  • 95
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    Biopolymers 10 (1971), S. 2029-2037 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variation of the polarized components of fluorescence of a rodlike particle bearing a fluorescent label upon partial orientation is calculated for some special geometry of the dye macromolecules complexes. Explicit expressions are given for the case where the energy of the molecule in the field depends only on one angle θ, showing that the result is a function of both 〈sin2θ〉 and 〈sin4θ〉. For the case of orientation in an electric field through an anisotropic induced moment, the expressions allow the calculation of this anisotropy of polarizability. The method is applied to the measurement of the polarizability of rodlike fragments of DNA labeled by intercalated molecules of Acridine Orange.
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  • 96
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    Biopolymers 10 (1971), S. 2039-2048 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As the temperature of solid poly(β-benzyl-L-aspartate) (PBLA), (CO.NH.CH.-CH2COOCH2C6H5)n, in the α-helieal form is raised from -150 °C, tlie line width and second moment of the proton magnetic resonance (PMR) signal decrease in stages until the conformational transition to the ω-helix occurs at about 90 °C. A similar temperature dependence of the PMR parameters is observed as the transformed polymer is cooled. Below -100°C (where the lattice is presumed to be rigid), the measured second moments are 9.5 Oe2 and 10.7 Oe2 for the α and ω forms, respectively. Second moments, calculated from the Van Vleck formula for the rigid lattice and also estimated for possible motional cases in which the polymer is taken to be in the ω form, are compared with the PMH data. By combination with the results of X-ray diffraction and infrared spectroscopic measurements, a tentative explanation can be made of the types of motion occurring in PBLA.
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  • 97
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    Biopolymers 10 (1971), S. 2133-2145 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have performed potentiometric titrations of poly-L-lysine. From these data we have calculated the free energy and enthalpy changes for the folding of the random coil to the α-helix in 10% ethanol (-120 and -120 cal/mole) and from the random coil to the β-structure in water (-140 and 870 cal/mole) and in 10% ethanol (-180 and 980 cal mole). Comparison of these values with each other and with values for the coil → α- helix transition in water (-78 and -880 cal/mole) led to the following conclusions. The stabilization by ethanol of ethanol of the α-helix with respect to the coil is that predicted from the known free energy of transfer of the peptide group from water to 10% ethanol. Similar data to explain the enthalpy difference are not available. The thermodynamic functions for the transition from α-helix to β-structure, obtained by subtracting those for the coil → α-helix and coil → β-structure transitions, are explained from a consideration of the structural differences: non bonded interactions of the polypeptide backbone are less favorable in the β-structure than in the α-helix, causing an increase in the energy, while hydrophobic contacts between side chains raise the entropy of the β-structure as compared with the α-helix, so that the free energy difference between the two structures is small, but enthalpy and entropy differences are large. The observation of only small differences in the free energy and enthalpy changes for the transition from coil β-structure upon going from water to 10% ethanol is expected by considering both the free energy of transfer of the peptide group (as for the α-helix) and the free energy and enthalpy of transfer of the apolar part of the side chain involved in hydrophobic bond formation.
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  • 98
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    Biopolymers 10 (1971), S. 2209-2221 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Valine specific transfer RNA (tRNAVal) was isolated from Bacillus stearothermophilus and Escherichia coli by chromatography on benzoylated DEAE-cellulose (BD-cellulose). Likewise isoleucine specific transfer RNA (tRNAIle) was isolated from B. stearothermophilus and from Mycoplasma sp. Kid. The thermal denaturation profiles (melting curves) of the two tRNAVal species in the presence of Mg+ + were nearly identical. However, the Tm for the Kid tRNAIle was about 10°C lower than that for the B. stearothermophilus tRNAIle. A nuclease and tRNA-free aminoacyl-tRNA synthetase (AA-tRNA synthetase) preparation from B. stearothermophilus was able to function efficiently at temperatures up to 80°C in the aminoacylation of all four tRNA species. Determination of the amino acid-acceptor activity of each tRNA species as a function of temperature of the aminoacylation reaction showed in each case a strong correlation between the loss of acceptor activity and the thermal denaturation profile of the tRNA. Evidence is presented that the loss in acceptor activity is most likely due to a change in structure of the tRNA as opposed to denaturation of the enzyme. These results further support the idea that correct secondary and/or tertiary structure must be maintained for tRNA to be active as a substrate for the AA-tRNA synthetase.
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  • 99
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    Biopolymers 10 (1971), S. 2275-2281 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Cotton effects of N-acetoacetyl amino acids and derivatives were examined by a circular dichroism technique. A correlation has been established between the sign of the Cotton effect and the absolute configuration of the asymmetric center. The L derivatives show, in dioxane, negative circular dichroism curves, whereas the D antipodes present positive curves. The effect of solvent and pH and influence of alkylation at the amide nitrogen are also discussed.
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  • 100
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    Biopolymers 10 (1971), S. 2345-2358 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The anisotropy of electrical polarizability of rodlike fragments of DNA has been studied by a number of electro-optical methods: Kerr effect (combined with flow birefringence), light scattering, diehroism, and fluorescence in an electric field. The most sensitive technique (Kerr effect) has been used to study the variation of the polarizability with the nature and concentration of counteroins. DNA fragments constitute a truly rigid polyelectrolyte of known structure. The value obtained can then be quantitatively compared to the predictions of those of the theories of the longitudinal polarizability of rigid polyelectrolytes which are based on true molecular parameters. The comparison emphasizes the role of the counterion-counterion repulsion. Oosawa's theory seems to represent the best approach but fails to explain the differences observed between monovalent and divalent ions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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