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  • 1965-1969  (23.934)
  • Chemistry  (23.845)
  • Cat  (55)
  • Insulin  (35)
  • Nuclear reactions
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  • 1
    Digitale Medien
    Digitale Medien
    Über Wirkungen von N-Amidino-3,5-diamino-6-chloro-pyrazin-carboxamid (Amilorid) auf den Glucosetransport und den Leucineinbau in Proteine des epididymalen Fettgewebes der Ratte (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 139-151 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Amiloride ; Insulin ; Glucose Transport ; Leucine Incorporation ; Isolated Adipose Tissue ; Amilorid ; Insulin ; Glucosetransport ; Leucineinbau ; isoliertes Fettgewebe
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Die Aufnahme von Glucose ins isolierte epididymale Fettgewebe und die Bildung von 14CO2 aus [1-14C]-Glucose wurde als Maß von Transportvorgängen, die Incorporation von [1-14C]-Leucin ins Fettgewebsprotein als Maß der Proteinsynthese vor und nach Zusatz von Amilorid in vitro verwendet. 2. Amilorid setzt den Transport durch die Membran sowohl ohne als auch mit Stimulierung durch Insulin halbmaximal in 10−4 M-Konzentration herab. Aus der Kinetik des Transportes kann geschlossen werden, daß Amilorid die maximale Geschwindigkeit des gesamten Vorganges verlangsamt, ohne die Transportkonstante zu verändern. 3. Der Einbau von Leucin ins Fettgewebsprotein wird durch Amilorid in 3 · 10−4 M-Konzentration auf ein Zehntel herabgesetzt. Das Verhalten von [1-14C]-α-Aminoisobuttersäure läßt den Schluß zu, daß der Aminosäuretransport durch die Membran des Fettgewebes nicht beeinflußt wird. 4. Die Wirkungen des Amilorids am Fettgewebe entsprechen im Prinzip denjenigen des Triamterens und des 6-Aminonicotinsäureamids. Ebenso ist allen gemeinsam, daß sie den renalen Natrium- und Kaliumtransport im distalen Abschnitt des Nephrons hemmen. 5. Es ist möglich, daß ein Zusammenhang zwischen den hemmenden Wirkungen dieser Pharmaka auf den Leucin-Einbau in das Fettgewebsprotein und der Störung von Transportvorgängen durch biologische Membranen besteht.
    Notizen: Summary 1. The uptake of glucose and the formation of 14CO2 from [1-14C]-glucose were used as a measure of transport processes, and the incorporation of [1-14C]-leucine into the protein of adipose tissue served as a measure of protein synthesis before and after the addition of amiloride to the isolated epididymal adipose tissue of the rat in vitro. 2. In a concentration of 10−4 M, amiloride decreases the glucose transport through tissue membranes by 50% with and without stimulation by insulin. It can be deduced from the kinetics of the transport that amiloride slows down the maximal velocity of the complete process without influencing the transport constant. 3. The incorporation of leucine into adipose tissue protein was diminished to 10% by amiloride in a concentration of 3 × 10−4 M. Experiments with [1-14C]-α-aminoisobutyric acid allow the conclusion that the amino acid transport through the membrane of the adipose tissue remains uninfluenced. 4. The effects of amiloride on the adipose tissue are similar to those of triamterene and of 6-aminonicotinamide. In addition, they all inhibit renal sodium and potassium transport in the distal part of the nephron. 5. It is possible, that there is a connection between the inhibiting effects of these drugs on the incorporation of leucine into the protein of adipose tissue and the disturbance of transport processes through biological membranes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00537655
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  • 2
    Digitale Medien
    Digitale Medien
    Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The cardiac glyoosides digitoxin, ouabain, digoxin and peruvosid labelled with3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine. 2. Calculation of the amount of glycosides totally absorbed from the3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%. 3. The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood. 4. The amount of glycoside excreted in the bile is for peruvosid 15,5% of the amount absorbed, for ouabain 1,9%, for digoxin 1,4% and for digitoxin 0,8%. The3H-activity excreted in urine is very small and can be disregarded. 5. Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only 1/4. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01002379
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  • 3
    Digitale Medien
    Digitale Medien
    Über die Gefäßversorgung des Corpus callosum der Katze (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Arterial supply ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An 27 Katzen beiderlei Geschlechts wurde die Blutversorgung des Corpus callosum untersucht. Dabei wurden folgende Befunde erhoben: Der Balken der Katze wird im Bereich des Rostrum und Genu sowie im vorderen und mittleren Truncuabschnitt aus der Arteria cerebri anterior versorgt und zwar über Äste, die den Arteriae pericallosae und den Arteriae genu corporis callosi entstammen. Diese Äste wurden als Arteriae callosi superiores und inferiores bezeichnet. Lediglich im hinteren Truncusabschnitt und im Splenium erfolgt die Versorgung neben Ästen der A. pericall. auch über solche der Arteriae cerebri mediae und posteriores. Die Blutgefäße treten dolchartig in den Balken ein, teilen sich dann baumartig weiter auf und gehen in ein Capillarnetz über, das in Richtung des Nervenfaserverlaufes ausgezogen ist. Auf in der Literatur bereits bekannte, aber oft vernachlässigte Besonderheiten der Arteria carotis interna und des Circulus arteriosus wird hingewiesen.
    Notizen: Summary In investigations on 27 cats of both sexes, the arterial supply of the corpus callosum was studied. The findings are as follows: In the region comprising rostrum and genu as well as in the fore and middle trunk sections, blood supplied by branches of the arteriae pericallosae and the arteriae genu corporis callosi which originate from the arteria cerebri anterior. These branches were designated arteriae callosi superiores and inferiores. However, in the posterior section of the trunk and in the splenium the blood is supplied by branches of the aa. pericall. and, in addition, by branches of the arteriae cerebri media and posteriores. The blood vessels penetrate the corpus callosum in bayonet fashion, then arborise and finally become a capillary network which is elongated in the direction of the course of the nerve fibres. Attention is drawn to peculiarities of the arteria carotis interna and the circle of Willis which, although known in the literature, are rarely referred to.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00522492
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  • 4
    Digitale Medien
    Digitale Medien
    Quantitative Untersuchungen an Gliazellen im Corpus callosum wachsender Katzen nach Perfusions- und Immersionsfixierung (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Gehirne von Tieren aus 4 verschieden alten Würfen junger Katzen wurden teils lebensfrisch durch Perfusion, teils nach 24 Std durch Immersion fixiert und für Vergleichsuntersuchungen in Paraffin eingebettet. Bei Betrachtung der Gliazellen des Corpus callosum ergab sich: 1. Nach Perfusionsfixierung sind die Kerne der Gliazellen groß und elliptisch. Sie sind wasserklar und haben eine scharf gezeichnete Chromatinstruktur. Nach Immersionsfixierung 24 Std p.m. sind die Kerne dagegen klein und rund, homogen dunkel gefärbt und haben ein kaum zu erkennendes Chromatingerüst. 2. Nach Perfusionsfixierung sieht man im Balken der ganz jungen Tiere zahlreiche Mitosen. Sie fehlen bei den durch Immersion fixierten Geschwistertieren desselben Wurfes. 3. Die nach verschiedener Fixierung beobachteten Unterschiede in der Form der Gliazellkerne werden durch Messungen der Quer- und Längsachsen erfaßt.
    Notizen: Summary In four litters of young cats, some of the brains were fixed by perfusion and the others by immersion. The material was embedded in paraffin and the neuroglia was investigated in sections through the corpus callosum. It was found that: 1. After fixation by perfusion the nuclei of the glia cells are large and elliptic. The caryoplasm is clear and there is a distinct structure of the chromatin. After fixation by immersion the nuclei of the same cells are small and round. The caryoplasm is dense and the structure of the chromatin is not clearly visible. 2. After fixation by perfusion mitotic figures are present. They are absent in the brains fixed by immersion. 3. Following different fixation, there are differences in the shape of the nuclei of the glial cells. These differences have been investigated in detail by measuring the diameters of the nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00521281
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  • 5
    Digitale Medien
    Digitale Medien
    Effect of insulin on glucagon enhanced lipolysis in vitro (1969)
    Springer
    Diabetologia 5 (1969), S. 195-197 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; glucagon ; adipose tissue ; lipolysis ; FFA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé A des concentrations proches de celles qui sont rencontrées dans le plasma humain, le glucagon stimule fortement la lipolyse au niveau de la graisse épididymaire du rat, étudiéein vitro. Les effets de telles concentrations de glucagon sont réduits, voire abolis par l'insuline aux concentrations de 25 et 100μU/ml. Rapprochées de l'effet insulinogénique puissant du glucagon, ces observations peuvent fournir une explication quant au caractère retardé de l'élévation du taux sanguin des acides gras libres observée après injection de glucagonin vivo.
    Kurzfassung: Zusammenfassung Glucagon stimuliert in Konzentrationen, wie sie auch im menschlichen Plasma vorkommen, die Lipolyse im Ratten-Nebenhodenfettgewebein vitro stark. Die Effekte derartiger Glucagonkonzentrationen werden durch Insulin (25–100μE/ml) verringert bis aufgehoben. Unter Berücksichtigung der ausgeprägten Wirkung von Glucagon auf die Insulinfreisetzung können diese Beobachtungen eine Erklärung für die Verzögerung des Anstiegs der freien Fettsäuren im Serum liefern, die man nach Glucagoninjektionenin vivo beobachtet.
    Notizen: Summary Glucagon in concentrations similar to those found in human plasma markedly stimulates lipolysis in rat adipose tissuein vitro. The effects of these “physiological” concentrations of glucagon are reduced or abolished by insulin at concentrations of 25 and 100μU/ml. Considering the marked insulinogenic effect of glucagon these observations may provide an explanation for the delayed increase of blood FFA observed after glucagon injectionin vivo.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01213680
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  • 6
    Digitale Medien
    Digitale Medien
    Insulin release by isolated pancreatic islets of the mouse incubated in vitro (1969)
    Springer
    Diabetologia 5 (1969), S. 61-66 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; islets of Langerhans ; mouse ; collagenase ; glucose ; mannoheptulose ; glucagon ; adrenaline ; phentolamine ; theophylline ; tolbutamide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé La libération de l'insuline pendant l'incubation des îlots de Langerhans de la souris, isolés après digestion du pancréas par la collagénase, a été étudiée, et l'influence de divers facteurs sur la vitesse de libération a été recherchée. Le glucose à 3.0 mg/ml (glucose élevé) stimulait la libération d'insuline, mais n'avait pas d'effet à 0.6 mg/ml (taux bas). Le mannoheptulose bloquait la stimulation provoquée par du glucose élevé, comme le faisait l'adrénaline. L'effet de l'adrénaline était aboli par la phentolamine, un agent bloquant alpha adrénergique. Le glucagon seul, ainsi qu'en pre'sence d'un taux de glucose bas, stimulait la libération d'insuline, mais non de façon constante avec un taux de glucose élevé. L'adrénaline abolissait la stimulation provoquée par le glucagon. La théophylline stimulait la libération lorsque le glucose était bas, mais beaucoup moins lorsque le glucose était élevé et pas du tout avec le glucagon, quelle que soit la concentration de glucose. Le tolbutamide stimulait la libération d'insuline avec une faible concentration de glucose et cet effet n'était pas inhibé par l'adrénaline. La convenance de cette préparation pour des études sur le métabolisme des cellules insulaires et sa relation avec la sécrét ion d'insuline est discutée.
    Kurzfassung: Zusammenfassung Es wurde die Insulinausschüttung aus Langerhans'schen Inseln von Mäusen, die durch Kollagenase-Behandlung des Pankreas gewonnen worden waren, untersucht und der Einfluß verschiedener Faktoren auf die Freisetzungsgeschwindigkeit überprüft. Eine hohe Glucose-Konzentration von 3.0 mg/ml förderte die Insulin-Ausschüttung, während die niedrige Konzentration von 0.6 mg/ml keine Wirkung ergab. Mannoheptulose und Adrenalin blockierten die Stimulation durch die hohe Glucosekonzentration. Der AdrenalinEffekt konnte durch Phentolamin, eine alpha-Rezeptoren blockierende Substanz, wieder aufgehoben werden. Glucagon führte allein und in Gegenwart der niedrigen Glucosekonzentration zu einer verstärkten Insulininkretion: dies war jedoch bei Kombination mit der hohen Glucosekonzentration nicht konstant der Fall. Adrenalin hob die Stimulierung durch Glucagon auf. Theophyllin führte bei Gegenwart der niedrigen Glucosekonzentration zu einer gesteigerten Ausschüttung, dieser Effekt trat unter der höheren Glucosekonzentration in wesentlich geringerem Umfang und bei Zusatz von Glucagon und einer der beiden verwandten Glucosekonzentrationen überhaupt nicht auf. Bei niedriger Glucosekonzentration stimulierte Tolbutamid die Insulinfreisetzung; dieser Effekt ließ sich durch Adrenalin nicht aufheben. Die Aussagefähigkeit dieses Präparates für Untersuchungen des Inselzell-Stoffwechsels und seiner Beziehungen zur Insulininkretion wird diskutiert.
    Notizen: Summary The release of insulin during incubation of mouse islets of Langerhans, isolated after digestion of the pancreas with collagenase, has been studied, and the influence of various factors on the rate of release investigated. Glucose at 3.0 mg/ml (high glucose) stimulated insulin release, but had no effect at 0.6 mg/ml (low glucose). Mannoheptulose blocked the stimulation by high glucose, as did adrenaline. The adrenaline effect was abolished by phentolamine, an alpha-adrenergic blocking agent. Glucagon alone, stimulated insulin release, and also with low glucose, but not consistently with high glucose. Adrenaline abolished the stimulation by glucagon. Theophylline stimulated release with low glucose, much less so with high glucose and not at all with glucagon at either glucose concentration. Tolbutamide stimulated release with low glucose, and this effect was not inhibited by adrenaline. The suitability of this preparation for studies of islet cell metabolism and its relationship to secretion of insulin is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01211999
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  • 7
    Digitale Medien
    Digitale Medien
    Insulin in bile (1969)
    Springer
    Diabetologia 5 (1969), S. 304-308 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; bile ; rabbit ; 125I-insulin ; glucose ; galactose ; fructose ; tolbutamide ; phenformin ; liver
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé On trouve de l'insuline immunoréactive dans la bile hépatique de lapins normaux. Moins de 1% d'une dose injectée d'insuline bovine atteint la bile. Quand de l'insuline bovine 125I, seule ou liée à l'anticorps, est administrée par voie intraveineuse, seulement 40% de la radioactivité retrouvée dans la bile est précipitable avec l'acide trichloracétique et moins de 10% réagit avec le sérum anti-insuline de cobaye. Le glucose, le fructose le galactose, le tolbutamide et la phenformine provoquent tous une élévation de l'insuline dans la bile, qui atteint son maximum 40 à 50 min après l'injection. L'alloxane atténue ou abolie ces réponses.
    Kurzfassung: Zusammenfassung Immunoreaktives Insulin wird in der Leber-Galle normaler Kaninchen gefunden. Weniger als 1% einer injizierten Dosis von Rinder-Insulin erreicht die Galle. Wenn man reines oder an Antikörper gebundenes 125I-Rinderinsulin intravenös verabreicht, lassen sich mit Hilfe von Trichloressigsäure nur 40% der Radioaktivität ausfällen, die in der Galle gefunden wird, und weniger als 10% reagieren mit Meerschweinchen-Anti-Insulinserum. Glucose, Fructose, Galaktose, Tolbutamide und Phenformin verursachen ein Ansteigen von Insulin in der Galle, welches ein Maximum innerhalb von 40 bis 50 Min. nach der Injektion erreicht. Alloxan vermindert oder hebt diese Effekte auf.
    Notizen: Summary Immuno-reactive insulin is found in the hepatic bile of normal rabbits. Less than 1% of an injected dose of bovine insulin reached the bile. When 125I-bovine insulin alone or complexed with antibody was given intravenously, only 40% of the radioactivity recovered in the bile was precipitable with trichloracetic acid, and less than 10% reacted with guinea pig anti-insulin serum. Glucose, fructose, galactose, tolbutamide and phenformin all caused an elevation in bile insulin, which reached a maximum 40 to 50 min after the injection. Alloxan attenuated or abolished these responses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00452903
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  • 8
    Digitale Medien
    Digitale Medien
    Experimentelle Untersuchungen über die blutzuckersenkende Wirkung von Rinder-Proinsulin (1969)
    Springer
    Diabetologia 5 (1969), S. 325-330 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; proinsulin ; blood sugar ; mice ; rats ; pancreatectomy ; nephrectomy ; hepatectomy (partial) alloxan diabetes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Chez les rats et les souris le taux du sucre sanguin est abaissé par une proinsuline obtenue à partir de l'insuline bovine (Schmidt et Arens [6]). Chez les rats alimentés et les souris à jeun, le rapport d'activité proinsuline: insuline est de 1∶4, chez les rats à jeun de 1∶2, dans le cas de dose équimolaire et en mesurant l'abaissement maximum du sucre sanguin. L'abaissement du sucre sanguin évolue de façon plus lente après proinsuline qu'après insuline. La proinsuline, incubée in vitro avec la trypsine, agit quantitativement et au point de vue temps, comme l'insuline. Chez les rats pancréatectomisés, chez les rats néphrectomisés ainsi que chez ceux hépatectomisés aux deux tiers, l'action de la proinsuline est la même que chez les animaux normaux. Les souris rendues diabétiques par l'alloxane répondent également à la proinsuline comme les souris intactes. L'action hypoglycémiante de la proinsuline se manifeste de façon retardée probablement parce que l'insuline active doit tout d'abord se former par un processus protéolytique dépendant du facteur temps. Ceci pourrait être aussi la raison pour laquelle, Rubenstein et coll. [5] signalent l'absence d'effet de la proinsuline dans le test de convulsion chez la souris.
    Kurzfassung: Zusammenfassung An Ratten und Mäusen wird der Blutzucker durch ein aus Rinderinsulin gewonnenes Proinsulin (Schmidt und Arens [6]) gesenkt. Bei gefütterten Ratten und nüchternen Mäusen ist das WirkungsVerhältnis Proinsulin: Insulin = 1∶4, bei nüchternen Ratten 1∶2, wenn äquiznolar dosiert und das Maximum der Blutzuckersenkung gewertet wird. Die Blutzuckersenkung verläuft nach Proinsulin protrahierter als nach Insulin. Proinsulin, welches in vitro mit Trypsin inkubiert wurde, wirkt quantitativ und zeitlich wie Insulin. Bei pankreatektomierten, bei nephrektomierten und bei zweidrittelhepatektomierten Ratten wirkt Proinsulin ebenso wie an Normaltieren. Auch alloxandidbetische Mäuse sprechen auf Proinsulin wie intakte Mäuse an. Die hypoglykämische Wirkung des Proinsulins tritt wahrscheinlich deshalb verzögert ein, weil das aktive Insulin in einem zeitabhängigen proteolytischen Prozeß erst entstehen muß. Dies könnte auch die Ursache für eine von Rubenstein et al. [5] zitierte, fehlende Wirkung von Proinsulin im Mäusekrampftest sein.
    Notizen: Summary Proinsulin obtained from bovine insulin (Schmidt and Arens [6]) lowered the blood sugar level of rats and mice. The activity ratio proinsulin: insulin was 1∶4 in fed rats and fasted mice, and 1∶2 in fasted rats, based on an equimolar dosage and measuring the effect in terms of maximum lowering of the blood sugar value. After proinsulin the decrease of the blood sugar was more protracted than after insulin. Proinsulin which was incubated with trypsin in vitro, resembled insulin in degree and onset of action. In pancreatectomized, nephrectomized and two-thirds hepatectomized rats proinsulin acted as in normal animals. Alloxan-diabetic mice responded to proinsulin like intact mice. The reason why the onset of the hypoglycaemic action of proinsulin was delayed is probably due to the fact that the active insulin must first be produced by a time-dependent proteolytic process. This may also be the cause of the ineffectiveness of proinsulin in the mouse convulsion test which was quoted by Rubenstein et al. [5].
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00452907
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  • 9
    Digitale Medien
    Digitale Medien
    Localization of insulin in mouse tissues using fluorescence microscopy and light microscope and high resolution autoradiography. (1969)
    Springer
    Diabetologia 5 (1969), S. 67-78 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; mouse tissues ; kidney fluorescence microscopy ; microscopy ; autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé La localisation d'insuline marquée avec I125 ou avec de l'isothiocyanate de fluorescéine a été étudiée au moyen d'autohistoradiographie au microscope optique, au microscope électronique et au moyen de microscopie à fluorescence dans les tissus de souris à jeun et de souris alimentées normalement. L'hormone fluorescente a été trouvée dans les cellules des tubules proximaux du rein de souris à jeun seulement, tandis que l'hormone radioactive a été repérée aussi dans le rein de souris alimentées, bien qu'en quantité inférieure à celle trouvée chez les souris à jeun. Au microscope électronique la radioactivité est présente dans le rein dans la bordure en brosse, les vacuoles et les mitochondries apicales et le noyau, mais pas dans l'appareil de Golgi ou dans les lysosomes. —L'hormone radioactive est aussi présente dans les autres tissus mais sans différence quantitative entre les souris à jeun et les souris alimentées. Les auteurs concluent que le procédé de ré-absorption de l'insuline par les cellules des tubules proximaux du rein est spécifique: l'hormone n'est pas dégradée de la même façon que les autres protéines mais probablement stockée afin de contrôler les processus métaboliques relevant des organelles subcellulaires dans lesquelles elle se trouve.
    Kurzfassung: Zusammenfassung Gefütterte und fastende Mäuse erhielten fluoreszierendes oder mit125J markiertes Insulin i.v. Die Lokalisation des Insulins in den Geweben wurde untersucht. Nur bei Tieren im Hungerzustand fand sich das fluoreszierende Hormon in den Nieren, während sich das radioaktive Insulin bei gefütterten und fastenden Tieren in den proximalen Tubulusschlingen der Nieren nachweisen ließ. Die fastenden Tiere schienen dabei mehr Radioaktivität aufzuweisen. Wurden die Nieren unter Verwendung von Techniken mit hohem Auflösungsvermögen untersucht, so fand sich die Radioaktivität im Bürstensaum, in den apikalen Vakuolen und Mitochondrien und dem Kern, jedoch nicht im Golgi-Apparat oder den Lysosomen. Alle anderen Gewebe enthielten Hormon-Radioaktivität, aber weder ihre Menge noch ihre Lokalisation unterschieden sich bei gefütterten und fastenden Tieren. Es wird gefolgert, daß der Prozeß der Insulinabsorption durch die Zellen der proximalen Tubulusschlingen spezifisch ist und daß das Hormon nicht in ähnlicher Weise wie andere Eiweißkörper abgebaut wird. Wahrscheinlich kommt es über eine Speicherung zu einer Steuerung der entsprechenden Stoffwechselprozesse in den subzellulären Organellen, in denen das Hormon sich befindet.
    Notizen: Summary Starved and fed mice were injected intravenously with either fluorescent or125I-insulin and the localization of the hormone was investigated in various tissues. The fluorescent hormone was found in the kidney of starved animals only, whereas the radioactive hormone was found in the proximal convoluted tubule cells of the kidney of both fed and fasted animals, although the latter group appeared to contain more radioactivity than the first. With high resolution techniques the radioactivity in the kidney was found in the brush border, the apical vacuoles, the apical mitochondria and the nucleus, and never in the Golgi apparatus or the lysosomes. All other tissues contained radioactivity due to the hormone, but no difference in either the amount or the localization was found between fed an starved animals. It is concluded that the process of absorption of insulin by the cells of the proximal convoluted tubules is specific and that the hormone is not degraded in a way similar to other proteins, but is likely to be stored and to control cellular metabolic processes from its sites of localization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01212000
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  • 10
    Digitale Medien
    Digitale Medien
    The stimulatory effect by insulin on the incorporation of32P radioactive inorganic phosphate into intracellular inorganic phosphate, adenine nucleotides and guanine nucleotides of the intact isolated rat diaphragm (1969)
    Springer
    Diabetologia 5 (1969), S. 79-87 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; 32P incorporation ; adenine nucleotides ; guanine nucleotides ; Na+K+ ATP-ase ; ouabain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Le but de ces investigations a été de contribuer à la compréhension du mécanisme d'action de l'insuline, en provoquant un turn-over accru du phosphate inorganique marqué au32P, en ATP et autres mononucléotides, dans le diaphragme du rat. Pendant l'incubation du diaphragme intact de rat dans un milieu bicarbonaté de Krebs Ringer, sans addition de substrat, on n'a pas observé d'effet de l'insuline sur le contenu en adénine-nucléotides, en guanine-nucléotides, y compris le 3′5′ AMP cyclique et le 3′5′ GMP cyclique. Quand du phosphate inorganique radioactif marqué au32P était présent dans le milieu, l'insuline augmentait l'activité spécifique du phosphate inorganique intracellulaire et provoquait une incorporation accrue du32P dans l'ATP et le GTP. L'effet sur l'ADP était moins prononcé. Il a été montré que ces effets de l'insuline dépendent de la composition ionique du milieu et du transport membranaire des ions. L'augmentation due à l'insuline de l'activité spécifique du phosphate inorganique intracellulaire et du marquage accru au32P de l'ATP (et du GTP) était en grande partie inhibée par l'ouabaïne. Pendant l'incubation dans les milieux où le chlorure de sodium a été remplacé isoosmotiquement par le chlorure de potassium ou de choline, les effets de l'insuline décrits ci-dessus étaient abolis. Les résultats indiquent que le marquage accru de l'ATP (et du GTP) provoqué par l'insuline, peut être en premier lieu attribué à des phénomènes survenant au niveau de la membrane cellulaire. L'augmentation de l'activité spécifique du phosphate inorganique intracellulaire en présence d'insuline, peut s'expliquer par une captation accrue du phosphate inorganique marqué au32P, à partir du milieu. Apparemment le marquage accru au32P de l'ATP (et du GTP) est une conséquence secondaire. On suggère que cet effet de l'insuline est d'abord en rapport avec un effet sur les enzymes de la membrane, en particulier sur l'ATP-ase activée par Na+, K+ et Mg2+.
    Kurzfassung: Zusammenfassung Ziel dieser Untersuchungen war es, zu einem besseren Verständnis der stimulierenden Wirkung von Insulin auf den Einbau von anorganischem32P Phosphat in ATP und andere Mononucleotide im Rattenzwerchfell beizutragen. Während der Inkubation intakter Rattenzwerchfelle in Krebs-Ringer-Bicarbonat Puffer ohne Substratzusatz konnte kein Insulineffekt auf den Gehalt an Adenonucleotiden und Guaninnucleotiden, sowie von cyclischem 3′,5′ AMP und cyclischem 3′,5′ GMP beobachtet werden. In Gegenwart von anorganischem32P Phosphat steigerte Insulin die spezifische Aktivität von intrazellulärem anorganischen Phosphat und bewirkte einen verstärkten Einbau von32P in ATP und GTP. Die Wirkung auf ADP war weniger ausgeprägt. Es konnte gezeigt werden, daß diese Insulineffekte von dem IonenGehalt des Mediums und dem Membrantransport der Ionen abhängen. Die Steigerung der spezifischen Aktivität des anorganischen Phosphates und der Markierung von ATP (und GTP) mit32P ließ sich weitgehend durch Ouabain wieder aufheben. Bei Inkubation in Pufferlösungen, die statt NaCl isoosmolare Mengen von KCl oder Cholinchlorid enthielten, waren die oben erwähnten Insulineffekte nicht mehr nachweisbar. Die Resultate sprechen dafür, daß die verstärkte Markierung von ATP (und GTP) unter Insulin in erster Linie auf Vorgängen an der Zellmembran beruht. Die erhöhte spezifische Aktivität des intrazellulären anorganischen Phosphates in Gegenwart von Insulin läßt sich durch einen verstärkten Einstrom von32P Phosphat aus dem Medium erklären. Augenscheinlich kommt es dadurch sekundär zu einer gesteigerten32P Markierung von ATP (und GTP). Wir möchten annehmen, daß dieser Insulineffekt vorwiegend über die Membranenzyme erfolgt und sich vor allem auf die Na+, K+ und Mg++ aktivierbare ATPase erstreckt.
    Notizen: Summary The aim of these investigations has been to contribute to an understanding of the mechanism of action of insulin in promoting increased turn over of32P inorganic phosphate into ATP and other mononucleotides in the rat diaphragm. During incubation of the intact rat diaphragm in Krebs Ringer bicarbonate medium without addition of substrate, no effect of insulin on the content of adenine nucleotides and guanine nucleotides including cyclic 3′,5′ AMP and cyclic 3′,5′ GMP has been observed. When32P radioactive inorganic phosphate was present in the medium, insulin increased the specific activity of intracellular inorganic phosphate and promoted an increased incorporation of32P into ATP and GTP. The effect on ADP was less pronounced. It has been shown that these effects of insulin depend upon the ionic composition of the medium and on ion membrane-transport. The insulin-promoted increase of specific activity of intracellular inorganic phosphate and of increased32P labelling of ATP (and GTP) was to a great extent inhibited by ouabain. During incubation in media where sodium chloride had been iso-osmotically replaced by potassium chloride or choline chloride, the above mentioned effects by insulin were abolished. The results indicate that the increased labelling of ATP (and GTP) promoted by insulin can be primarily attributed to events occuring at the cell membrane. The increased specific activity of intracellular inorganic phosphate in the presence of insulin can be explained by increased uptake of32P inorganic phosphate from the medium. Apparently the increased32P labelling of ATP (and GTP) occur as a secondary consequence. It is suggested that this insulin effect is primarily concerned with an effect on membrane enzymes, particularly the Na+, K+, Mg2+ activated ATP-ase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01212001
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  • 11
    Digitale Medien
    Digitale Medien
    Inability of galactose to mobilize insulin in galactokinase-deficient individuals (1969)
    Springer
    Diabetologia 5 (1969), S. 143-145 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Insulin ; galactose ; galactokinase ; deficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Chez deux adultes souffrant d'une déficience en galactokinase la charge orale de galactose a été suivie d'une hypergalactosémie prolongée sans aucune élevation de l'insuline immunoréactive plasmatique.
    Kurzfassung: Zusammenfassung Orale Belastung mit Galactose führte bei zwei Erwachsenen mit Galactokinasemangel zu einer prolongierten Hypergalactosämie, aber nicht zu einem Anstieg des immunoreaktiven Insulins im Plasma.
    Notizen: Summary Oral galactose loading in two galactokinase-deficient adults produced the expected high and prolonged rise of galactose in peripheral blood, but no rise of circulating immunoreactive insulin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01213671
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  • 12
    Digitale Medien
    Digitale Medien
    The lateral cervical nucleus in the cat IV. A light and electron microscopical study after midbrain lesions with demonstration of indirect wallerian degeneration at the ultra-structural level (1969)
    Springer
    Experimental brain research 7 (1969), S. 51-67 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The lateral cervical nucleus (LCN) has been studied with the light and electron microscope after midbrain lesions in kittens of different ages, and in adult cats. It has been shown that nerve cells remain within the contralateral LCN after hemisection of the midbrain. performed on 1 day old kittens. The estimated number of these remaining cells was 3–19% in the different cases. No fibers descending to the LCN from levels rostral to the midbrain could be demonstrated in adult cats with the Nauta technique. A combined Nauta and electron microscopical investigation was performed on kittens operated on at different ages and allowed to survive varying times postoperatively. At the operations the LCN-axons were transected at midbrain level. The Nauta investigation demonstrated silver impregnation of degenerating LCN-neurons on the affected side of the same type as has been described recently in other neuronal systems following axonal transection. The ultrastructural study revealed electron dense degenerating dendrites and probably also nerve cells within the LCN. The dense degenerative changes were very similar to the dense degeneration in terminal boutons following transection of parent axons. The potential value of the findings for electron microscopical research in neuroanatomy is discussed. The results in terms of connections of the LCN are discussed in the light of known anatomical and physiological data of the LCN.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236107
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  • 13
    Digitale Medien
    Digitale Medien
    Integration konvergierender Afferenzen in der bulbären Formatio Reticularis der Katze (1969)
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Ein konditionierender corticaler Reiz inhibiert den somatischen Startlereflex bei Katzen unter Chloralosenarkose für eine Dauer von mehr als 200 ms. Die Interaktionen zwischen beiden Reizen laufen in der bulbären und pontinen Formatio reticularis ab. 2. Dem Startlereflex liegt eine polysynaptische Erregungsschleife zugrunde, die die bulbäre und pontine Formatio reticularis durchzieht. Die Resistenz der reticulären Neurone gegenüber repetitiver Stimulation wurde als Kriterium ihrer funktionellen Lokalisation auf dem polysynaptischen Reflexbogen gewertet. 3. Die corticale Inhibition wird im Verlaufe der polysynaptischen Erregungsschleife zunehmend stärker. Neurone, die von den Startlereflexafferenzen direkt erregt werden, werden durch den corticalen Reiz nicht inhibiert. Dies schliebt eine präsynaptische Inhibition der reticulopetalen Fasersysteme aus.
    Notizen: Summary 1. The startle reflex evoked by cutaneous stimulation in cats under chloralose anesthesia is inhibited for more than 200 ms by a conditioning cortical volley. The interaction between the cutaneous and the cortical volley takes place in the bulbar and pontine reticular formation. 2. The startle reflex involves a series of reticular neurones. Resistance to repetitive stimulation has been determined to evaluate the functional localization of each neurone within this polysynaptic path. 3. Inhibition following the cortical volley becomes increasingly more effective along the course of the polysynaptic path and is completed within 5–6 ms. Reticular neurones excited directly by the spino-reticular afferents are not inhibited, thus excluding a presynaptic inhibition of the spinoreticular fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235440
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  • 14
    Digitale Medien
    Digitale Medien
    Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells (1969)
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Examination of cutaneous receptive fields (RFs) of lamina 5 cells in the lumbar spinal cord of decerebrate cats shows them to have three distinct zones with respect to mechanical and electrical stimulation. The mean response rate to both mechanical and electrical stimulation in zone 1 increases steadily up to the highest strengths used; in zone 2, surrounding zone 1 mainly proximally, mild stimuli reduce the mean rate, stronger stimuli increase it; in zone 3, mainly proximal to zone 2, all stimuli reduce the rate. Temporally, zone 1, electric shocks near threshold produce bursts of firing followed by inhibition. With increased stimulus strength, the bursts lengthen to a second or more. In zones 2 and 3, inhibition at all strengths is preceded at higher strengths by bursts of firing. Cold-blocking the spinal cord at lower thoracic levels reversibly increases the ongoing activity of these cells, increases the area of zones 1 and 2, and almost completely suppresses all inhibition. Stimulation of dorsal columns and threshold stimulation of distant dorsal roots inhibits ongoing and induced activity. Barbiturate decreases ongoing activity and the duration of firing produced by cutaneous electrical stimulation but does not decrease inhibition. These results are consistent with a model in which low-threshold fibres are excitatory only over a small central area of the RF of a lamina 5 cell (zone 1), high threshold fibres are excitatory over a larger area (zones 1 and 2), and low threshold fibres are inhibitory over the entire receptive field (zones 1, 2 and 3) with a slower time-course. This inhibition is tonically enhanced by descending influences in the decerebrate cat. It is suggested that the high and low threshold fibres correspond approximately to the small and large diametre fibres whose balance is the basis for the coding of pain in the theory of melzack and wall.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235240
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  • 15
    Digitale Medien
    Digitale Medien
    Die Bedeutung der Vorderhirnkommissuren für die Koordination bilateraler EEG-Muster (1969)
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Spontaneous EEG-patterns and evoked potentials (EP's) of symmetrical cortical areas were recorded in chronic and acute cats before and after section of the corpus callosum, the commissura anterior and posterior and the massa intermedia. The spontaneous EEG was recorded without and with anesthesia, EP's after electrical stimulation of the fore-paws only during nembutal anesthesia. — No changes in the bilateral coordination of spontaneous and evoked EEG-patterns could be seen after commissurotomy (CT). The bilateral coherence of EEG-waves as revealed by cross-correlation is low already in the normal cats and does not change significantly after CT. The values of cross-correlation coefficients at T = ± 15 msec vary during one EEG-record between -0.25 and +0.25 in the somatosensory, suprasylvian and temporal areas (mean values slightly above 0). In the visual area occasionally positive values between 0.5 and 0.8 were seen, but also here a large variation was found in all animals and the mean values were below 0.1. No consistent phase shift between both sides was observed. EEG-patterns like spindles or arousal, still occurred together in both hemispheres after CT, the variability of their exact beginning or end was the same as in controls. Spontaneous spindles often lasted longer after section of the massa intermedia. Homolateral EP's in the somato-sensory area were still present after CT. Rhythmical afterdischarges could be restricted to the contralateral somato-sensory cortex even before CT.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239029
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  • 16
    Digitale Medien
    Digitale Medien
    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235450
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  • 17
    Digitale Medien
    Digitale Medien
    Pyramidal control of fusimotor neurons supplying extensor muscles in the cat's forelimb (1969)
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of cortical stimulation upon dynamic and static sensitivities of the sensory endings in muscle spindles have been analyzed. 63 single afferent fibers from the muscle spindles of the forelimb extensors: M. flexor carpi radialis, M. flexor digitorum communis and M. palmaris longus were isolated in dorsal root filaments in 20 adult cats under chloralose-urethane anesthesia. They were identified by their response to stimulation of the median nerve. 1. Surface anodal repetitive stimulation of the anterior sigmoid gyrus was found to produce an enhancement of static response of single Group II fibers. Effective area was localized in a restricted region which corresponded to the forelimb motor area. The effect was obtained without any concomitant muscle contraction. Similarly, the stimulation increased the resting discharges of the Group Ia fibers from the same muscles. 2. Stimulation of the same area in the cerebral cortex was also found to increase the dynamic sensitivities of primary sensory endings. The increase was revealed by an enhancement of initial burst discharge during relaxation period of a twitch contraction caused by median nerve stimulation. 3. These results indicate that stimulation of the forelimb motor area has a facilitatory effect on both the static and dynamic fusimotor neurons innervating the muscle spindles of the test muscles. 4. The effects were reproduced in pyramidal tract preparations in which the brainstem was cut either at the level of the midbrain except for the cerebral peduncle or at the level of caudal medulla oblongata sparing the pyramid. 5. The threshold for the fusimotor effects was less than 1.3–1.5 times threshold of the pyramidal tract discharge, when the best spot for eliciting the fusimotor response was chosen. These results indicate that the effects of cortical stimulation are mainly mediated by the fast conducting pyramidal tract fibers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238324
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  • 18
    Digitale Medien
    Digitale Medien
    Contrôle de l'activité des fibres fusimotrices dynamiques et statiques par la formation réticulée mésencéphalique chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Effects of repetitive stimulation of the mesencephalic reticular formation (MRF) on the static discharge and dynamic sensitivity of muscle spindle primary endings (soleus muscle) were studied in cats anaesthetized with Halothane (Fluothane). By progressive increasing the depth of anaesthesia three different fusimotor effects could be observed: 1. A static effect; the static discharge of the primary endings was strongly increased; the response to phasic stretch was decreased or remained unaltered. 2. A dynamic effect; the dynamic sensitivity of the primary endings was powerfully increased while the rate of discharge under static conditions was only slightly augmented. 3. A depressant effect; the static discharge and the dynamic sensitivity of primary endings were decreased. Repeated stimulation elicited successive static and dynamic effects. No specific regions within the MRF could be related to a particular effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235241
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  • 19
    Digitale Medien
    Digitale Medien
    Etude fonctionnelle du contrôle de l'activité des fibres fusimotrices dynamiques et statiques par les formations réticulées mésencéphalique, pontique et bulbaire chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 325-345 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. During a progressive increase of Fluothane (Halothane) anaesthesia, repetitive stimulation of the mesencephalic retioular formation (MRF) produces several fusimotor effects — static, dynamic or depressant — on primary endings of soleus muscle spindles (Vedel et Mouillac-Baudevin 1969). 2. Transection of the brain immediately rostral to the site of stimulation may increase the dynamic effect but does not alter the static or the depressant effects. 3. A section of the rubrospinal tract does not modify the fusimotor effects elicited by stimulation of the MRF. 4. Transections of the spinal cord have shown that the pathways responsible for the transmission of these effects are mainly situated in the ipsilateral ventral and ventrolateral funiculi which contain the efferent fibers from the pontine reticular formation (PRF), from the bulbar reticular formation (BRF) and from the vestibular nucleus. 5. Contra and ipsilateral PRF stimulation produces the static fusimotor effect; contralateral stimulation from a small anterior region produces the dynamic effect. 6. Stimulation of the lateral part of the ipsilateral BRF elicits the dynamic effect while stimulation of the medial part elicits the static effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235242
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  • 20
    Digitale Medien
    Digitale Medien
    Die asynchrone und lokal umschriebene Reizwirkung von Mittelfrequenz-Dauerströmen im Hypothalamus der Katze (1969)
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. In order to compare the selective value of repetitive cathodal pulses of 8 c.p.s. and of continuous sine-wave alternating currents of 5000 c.p.s. (middle frequency current) when applied to brain tissue, explorations were made in the region of the hypothalamus that had yielded defence and/or flight reactions in earlier experiments. The region was explored by stimulating each point in turn with both current forms. At the same time measurement was made of the impedance of the brain tissue, and the effects produced by altering the time of rise of the middle frequency current on threshold of responses were also studied. The experiments were carried out on unanaesthetized, freely moving cats. 2. Both stimulation types produced affective (“emotional”) responses. The patterns elicited by low frequency cathodal pulse stimulation were often associated with stimulus-bound phasic muscle activity, i.e., flapping of ears, and twitching of whiskers, or, rotation of the head. Such extraneous motor effects were rarely obtained when continuous middle frequency currents were applied, and were tonic in character when present. 3. Mapping of reactive points revealed that the area producing defence or flight following middle frequency stimulation is smaller in size than the field delimited by means of repetitive cathodal pulse stimulation. These results strongly suggest that spread of current can be reduced by using middle frequency current stimulation. This apparently local (and hence highly selective) action is paralleled by a lower impedance of the brain tissue to the rapidly changing polarity of this current. 4. The hissing (and/or growling) associated with the defence pattern showed adaptation to suddenly rising middle frequency currents of 30 secs duration. An increase in threshold of hissing occurred when the time of rise of the current was prolonged. Flight, in contrast, was obtained at the same critical intensity regardless of the time of rise of current. 5. The nature of the stimulatory action of middle frequency current (examined in the peripheral nerve by Wyss) and the advantages presented by this new method of brain stimulation are briefly discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238329
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  • 21
    Digitale Medien
    Digitale Medien
    The lateral cervical nucleus in the cat III. An electron microscopical study after transection of spinal afferents (1969)
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of terminal degeneration within the lateral cervical nucleus (LCN) after transection of its spinal afferent fibers 2 days–2 years earlier is described. The degeneration after 2 days was of both the neurofilamentous and dense type. The highest number of degenerating terminals, about 15%, was found after 4–5 days. Then most of the degenerating boutons were of the dense type. The degenerating terminals had synaptic contact with cell bodies and dendrites of LCN-neurons. Removal of the degenerating boutons seemed to be effected by a phagocytic cell present in increased number compared to the normal LCN. In cases with long survival times an increase in the number of astroglial filaments was observed. In an animal where the spinal afferents to the LCN had been cut 2 years earlier a decrease in medium size of the neurons was observed. The amount of dendritic spines was also considerably smaller than normally.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236106
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  • 22
    Digitale Medien
    Digitale Medien
    Inhibition in the medial geniculate body of the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Medial geniculate body ; Inhibition ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Inhibitory activity in the cat medial geniculate body (MG) was examined by stimulating electrically and acoustically the input and output of the MG. 2. A longer and more profound depression of excitability occurs following a click-evoked potential in the MG than in the inferior colliculus (IC) in both anesthetized and unanesthetized states. Recovery is cyclic in the barbiturate MG preparation. 3. Electrical stimulation of the brachium of the inferior colliculus (BIG) evokes a field potential in the MG consisting of clearly distinguishable presynaptic and postsynaptic components. The presynaptic component recovers rapidly, while the postsynaptic component requires 100–200 msec for full recovery. This depression of excitability is localized within the MG since cortical ablation does not alter its occurrence. 4. Stimulation of the BIC mimics the effects of click stimulation on single units. Excitatory, inhibitory and reverberatory responses are evoked by the BIC shock. Suppression of single unit activity correlates with the depression of excitability following a BIC-evoked field response. 5. Cortical stimulation can evoke antidromic and trans-synaptic unit responses in the MG, as well as causing a variety of inhibitory effects and reverberation. In view of the fact that cortical ablation does not impair the recording of these responses to afferent stimuli, it is suggested that the cortical-evoked responses are at least partly mediated by antidromic conduction to MG. 6. Evidence is presented that inhibitory effects of both afferent and cortical stimulation are due to active inhibition of MG unit activity. Speculations are made as to the mechanisms producing inhibition and reverberation in the MG.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236108
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  • 23
    Digitale Medien
    Digitale Medien
    Electronmicroscopic observations on the structure of the pontine nuclei and the mode of termination of the corticopontine fibres an experimental study in the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 95-110 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The electron microscopical changes occurring in the pontine nuclei following unilateral lesions of the primary sensorimotor cortex have been studied in 7 cats with a survival time from 2–23 days. A description is also given of the fine structure of the pontine regions in receipt of the fibres. These regions are shown in Fig. 1. The study shows that the boutons are practically only in synaptic contact with dendrites. The bouton density on these is only 16%. The boutons are of the en passage and terminal type, with the latter as the most common (Figs. 4a-e). The synaptic vesicles are rounded or elongated. The formaldehyde fixed material had 17.8% boutons with vesicles of the elongated type; the material fixed with a mixture of formaldehyde and glutaraldehyde had only 11.5% of such boutons. The degenerating boutons show the dark type of reaction and the majority of the corticopontine fibres are of the type shown in Figs. 4d and 4e. Astrocytes and microglial cells participate in the removal of degenerating boutons and terminal fibres. Degenerating boutons are present even at the 23 day stage and some have apparently only started to degenerate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235436
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  • 24
    Digitale Medien
    Digitale Medien
    Eine faktorenanalyse von schwellen subcorticaler reizantworten (1969)
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Evoked potential thresholds ; Factor analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur Beschreibung von Korrelationen zwischen zahlreichen elektrophysiologischen Daten aus verschiedenen Hirngebieten wurde eine Faktorenanalyse nach der Hauptachsenmethode gerechnet. Ausgangsmaterial dieser Analyse waren Schwellen subcortical ausgelöster und abgeleiteter Antwortpotentiale auf Einzelreize. Das resultierende Faktorenmuster ermöglicht ein quantitatives Konzept der Schwellendetermination subcorticaler Reizantworten und zugleich ein Modell von Funktionsbeziehungen zwischen einigen Hirnstrukturen. Die Reizungen und Ableitungen erfolgten bei 35 encéphale isolé-Katzen mit Hilfe bipolarer Elektroden in folgenden Arealen: Amygdala, Hippocampus, Septum, N. dorsomedialis Thalami, Hypothalamus posterior und Formatio reticularis mesencephali. Es wurden 435 Korrelationskoeffizienten zwischen den Schwellen von 30 subcorticalen Verbindungen gebildet und zum Zwecke einer Datenreduktion durch eine Matrix von 5 Faktoren reproduziert. 1. Jeder Faktor repräsentierte hohe Schwellenkorrelationen zwischen den efferenten Projektionen jeweils eines Kerngebietes. Demnach nimmt im allgemeinen die Aktivität des Reizortes den größten Einfluß auf die Schwelle eines Antwortpotentials. Diese Hypothese ist durch pharmakologische Untersuchungen belegt worden [27] 2. Kovariationen von Reizantworten mit identischen Ableiteorten ergaben sich ausnahmslos, wenn die Latenzzeiten mehr als 11 msec betrugen. 3. Zusätzlich zeigte die Faktorenmatrix Schwellenkorrelationen zwischen: a) den hypothalamischen Efferenzen und mehreren hippokampalen Afferenzen langer Latenz (positive Korrelationen) b) retikulo-limbischen Verbindungen und „primären” Efferenzen von Amygdala und Hippocampus (positive Korrelationen) c) Antwortpotentialen, die durch Reizung der Formatio reticularis, und solchen, die durch Reizung des N. Amygdalae ausgelöst waren (negative Korrelationen) d) den Efferenzen des N. dorsomedialis Thalami und limbischen Projektionen langer Latenz zur mesencephalen Formatio reticularis (positive Korrelationen) Die Interpretation dieser Zusammenhänge bestätigt und erweitert einige bekannte Modelle von Beziehungen zwischen subcorticalen Kerngebieten. Abschließend wird mit Rücksicht auf die Linearität der mathematischen Methode die Anwendbarkeit der Faktorenanalyse auf Schwellen von Reizantworten diskutiert.
    Notizen: Summary In 35 cats (encéphale isolé) evoked responses were elicited and recorded with bipolar electrodes from the amygdala, hippocampus, septum, dorsomedial thalamic nucleus, posterior hypothalamus, and mesencephalic reticular formation. Correlations between the thresholds of responses in different areas following stimulation of other areas were described by a factor analysis according to the principal axis method. 435 coefficients of correlation were calculated and reproduced by a matrix of 5 factors for the purpose of data reduction. Each factor represented high threshold correlations between the efferent projections of one region, which suggests that the activity of the stimulated site exerts a major influence on the evoked potential threshold. This is supported by pharmacological studies [27, 49]. Covariations of responses recorded in the same nucleus were always found, if the latencies exceeded 11 msec. The factor matrix indicated threshold correlations between: the efferent projections of the hypothalamus and several long latency afferent projections to the hippocampus (positive correlations); reticulo-limbic connections and “primary” efferent connections of the amygdala and hippocampus (positive correlations); evoked potentials following reticular and amygdaloid stimulation (negative correlations); the efferent projections of the dorsomedial thalamic nucleus and long latency limbic projections to the mesencephalic reticular formation (positive correlations). The interpretation of these relationships confirms and extends some well known models of relations between subcortical regions. The applicability of factor analysis to evoked potential thresholds is discussed with regard to the linearity of the mathematical method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234927
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  • 25
    Digitale Medien
    Digitale Medien
    Interaction of defence and flight reactions produced by simultaneous stimulation at two points in the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 130-149 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The results presented in the present paper are an extension of preceding work devoted to exploration of the hypothalamic defence and flight fields using coaxial electrodes with small cathode. In 33 cats simultaneous stimulation was applied to two points which upon single stimulation had yielded defence, flight, or defence and flight respectively. Results were compared with those produced at either point alone. In 2 cats combined stimulation of a defence and a flight point was carried out with a stuffed cat present. 2. The latencies and rates of the vocal effects associated with defence (growling and hissing), and the latencies of flight (jump from the table) were measured. 3. Simultaneous stimulation of two points which had yielded defence, or of two points which had yielded flight resulted in facilitation (spatial summation) of the effects evoked: a more complete defence response associated with decrease of the latencies and increase in the rates of the vocal effects; decrease of flight latencies and increase of flight impetuosity. 4. Simultaneous stimulation of a defence point which had yielded growling at lower threshold than hissing, and of a point which had yielded flight resulted in facilitation of hissing. Growling and flight were often suppressed; when they occurred, latencies were lengthened and growling rates were increased somewhat. 5. Stimulation of a defence point with a dummy present produces striking (fending off). Simultaneous stimulation of a flight point resulted in facilitation of both hissing and striking. 6. It is concluded that the complex patterns obtained when defence is combined with flight are the result of facilitatory and inhibitory interaction between the elements of the individual patterns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234535
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  • 26
    Digitale Medien
    Digitale Medien
    Räumliche summation und hemmungsvorgänge im receptiven feldzentrum von retina-neuronen der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. An retinalen Ganglienzellen der Katze wurde die räumliche Summation im receptiven Feldzentrum (KFZ) bei Dunkeladaptation und Helladaptation durch mittelpunktzentrierte Lichtreize verschiedener Flächengrößen untersucht. Als Kriterium dienten die Entladungsraten der ersten 200 und 500 msec nach Licht-an oder Licht-aus. Das Summationsverhalten wurde sowohl für Einzelneurone als auch gruppenstatistisch für die beiden Neuronen-Systeme B (on-Zentrum) und D (off-Zentrum) untersucht. 2. Die räumliche Summation ist auf den inneren Bereich des RFZ beschränkt: bei on-Zentrum-Neuronen steigt die Entladungsrate nur bis zu Reizflächen, die etwa 1/5 der Fläche des RFZ belichten, bei off-Zentrum-Neuronen bis zu Reizflachen von ca. 1/10 des RFZ. Bei Variation der Reizfläche zwischen 20 und 100% der Fläche des RFZ bleibt das Entladungsniveau konstant (asymptotischer Verlauf der Summationskurve). 3. Die Begrenzung der räumlichen Summation auf einen kleinen Bereich des RFZ beweist eine bereits im Feldzentrum wirksame Hemmung. Diese Zentrum-Inhibition begrenzt die Erregungssummation im RFZ bei zunehmender Flächengröße des Lichtreizes. 4. On- und off-Zentrum-Neurone unterscheiden sich in beiden Adaptationszuständen in der Höhe des Entladungsniveaus. Die Entladungsraten der on-Zentrum-Neurone nach Licht-an übertreffen um ein Mehrfaches die Entladungsraten der off-Zentrum-Neurone nach Licht-aus. Die Unterschiede sind gruppenstatistisch hoch signifikant. Die interneuronale Variabilität der Entladungsraten ist bei den onZentrum Neuronen erheblich geringer als bei den off-Zentrum-Neuronen. 5. Dunkel -und Helladaptation führt zu signifikantem Unterschied der Entladungsraten: bei Helladaptation liegt die Impulsrate beider Neuronentypen höher als bei Dunkeladaptation und der Summationsbereich ist um 5–10% größer. 6. Für die mathematische Beschreibung der Summationsverläufe ist die Hyperbel besser geeignet als die logarithmische und Potenzfunktion. Logarithmus- und Potenzfunktionen beschreiben den konstanten asymptotischen Teil der Summationskurven ungenügend und eigenen sich nur für den Kurventeil im innersten Summationsbereich. Die Bedeutung der Befunde für eine dynamische Interpretation der visuellen Feldorganisation und mögliche Beziehungen zur lateralen Umfeldhemmung werden diskutiert.
    Notizen: Summary 1. Spatial summation of suprathreshold light stimuli within receptive field centers (RFZ) of retinal ganglion cells was investigated during dark and light adaptation in cats. The mean discharge rates for 200 and 500 msec following light on or off were the computed response criteria. The summation effects were analyzed for single neurones and statistically for grouped neuron populations of the two neuronal subsystems B (on-center-neurones) and D (off-center-neurones). 2. Spatial summation is restricted to a small part of the RFZ. On-centerneurones increase their on-discharge rates with increasing spot sizes, only if the stimulus illuminates less than 1/5 of the RFZ. The summating area of the off-centerneurones is smaller (about 1/10 of the RFZ). 3. The limitation of spatial summation to a small part of the RFZ indicates the existance of inhibition within the RFZ. This center-inhibition sets a constant limit for excitation summation in the RFZ. 4. The mean neuronal response rates for the 2 subsystems show significant differences: The on-discharges of the on-center-neurones exceed the off-discharges of the off-center-neurones by a factor of 3–5. These highly significant differences occur at both adaptation levels and are not due to different spontaneous activity. Interneuronal response variability of the off-center-neurones was twice as large as that of the on-center-neurones. 5. Change from dark to light adaptation had only a small but significant influence on summation properties. The poststimulus discharge rates were higher during light adaptation and the summating area was slightly larger (about 5–10%). 6. A comparative curve fitting procedure for three suitable mathematical functions revealed that the hyperbola describes the neuronal summation curves better than a logarithmic or power function. The latter do not fit the constant asymptotic part of the curve. The significance of the results for a dynamic interpretation of the organisation of visual receptive fields is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234924
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  • 27
    Digitale Medien
    Digitale Medien
    Räumliche summation im receptiven feldzentrum von neuronen des geniculatum laterale der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Die räumliche Summation im receptiven Feldzentrum von Neuronen des Corpus geniculatum laterale (CG-L) wird beschrieben und mit entsprechenden Untersuchungen an retinalen Ganglienzellen verglichen. Neben größerer interneuronaler Variabilität ergeben sich ausgeprägtere Unterschiede der Summationseigenschaften der on-und off-Zentrum-Neurone. Der effektive Summationsbereich von etwa 1/5 der Fläche des RFZ ist in Retina und CGL etwa gleich. 2. Die on-Zentrum-Neurone des CGL zeigen in beiden Adaptationszuständen einen ähnlichen Summationsverlauf wie in der Retina. Das Entladungsnieau ist im CGL jedoch erheblich geringer und nicht durch Unterschiede in der Spontanaktivität zu erklären. 3. Die Mehrzahl der off-Zentrum-Neurone des CGL zeigt bei DA inverse Summationsverläufe wie in der Retina: durchgehende Verminderung der Entladungsrate der off-Antworten bei Vergrößerung der Reizfläche im RFZ. Eine kleine Gruppe zeigt einen parabelförmigen Summationsverlauf mit Entladungszunahme bis zu Reizflächen von 10–30% der Fläche des RFZ und darauffolgender Entladungsminderung. Bei Helladaptation zeigen fast alle off-Zentrum-Neurone diesen Parabelverlauf. Das durchschnittliche Entladungsniveau ist von dem retinaler offZentrum-Neurone nicht signifikant verschieden. 4. Die interneuronale Variabilität der Summationsvorgänge im RFZ von CGLNeuronen ist gegenüber den retinalen Ganglienzellen deutlich größer. Dies gilt insbesondere für die off-Zentrum-Neurone. Das Summationsverhalten von CGLNeuronen läßt sich daher nicht wie in der Retina durch einen Funktionstyp beschreiben. 5. Die Befunde sprechen für eine Transformation des retinalen Eingangs der off-Zentrum-Neurone im CGL, während die on-Zentrum-Neurone außer der bekannten Frequenzuntersetzung keine wesentliche Umformung erkennen lassen.
    Notizen: Summary 1. Spatial summation in the receptive field center of neurones of the lateral geniculate body (CGL) is limited by inhibition to a small part of field center. Variations of stimulus size are only effective if the stimulus is smaller than about 1/5 of the area of receptive field center. Thus, the active summating area of the field center in the CGL corresponds to that of the retina. Geniculate neurones, however, show less homogeneous responses and the summation properties of the two neuronal subsystems (on-center-and off-center-cells), show greater differences than in the retina. 2. The form of summation curves for the on-center-neurones of the CGL is similar to those of the retina at both adaptation levels. However, the average responses rates in the CGL are considerably lower. This is not due to differences of spontaneous activity. 3. The summation characteristics of off-responses of off-center-neurones of the CGL are quite different from those in the retina. In dark adaptation the majority of CGL neurones respond with decreasing discharge rates to increasing spot-sizes within the field center. A small number show an initial increase of discharge rates up to stimulus sizes of about 1/10 of the receptive field center before a decrease occurs. This parabolic summation type is typical for most off-center-neurones in light adaptation. The mean discharge levels are the same as those of the retinal offcenter-neurones. 4. The higher interneuronal variability of summation curves especially of the off-center-neurones of the CGL indicates a more complex determination of the discharge properties of CGL neurones. This functional differentiation of single neurones is congruent with the more complex structural and synaptic organisation in CGL. 5. With respect to spatial summation, the results indicate a transformation of the retinal input of the off-center-neurones at the geniculate level, whereas the oncenter-neurones are nearly unchanged.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234925
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  • 28
    Digitale Medien
    Digitale Medien
    Langfristige Verträglichkeitsprüfung mit Benperidol an der Katze (1969)
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Daily doses of 1–10 mg Benperidol were given perorally to cats during 26 months. The general behaviour and the EEG were unchanged during the treatment, in particular no signs of dyskinesia were observed. After discontinuation of the administration, the behaviour and the EEG of the animals stayed normal. Thus no lasting and irreversible side effects could be observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403690
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  • 29
    Digitale Medien
    Digitale Medien
    Effects of LSD on the spontaneous and evoked activity of retinal and geniculate ganglion cells (1969)
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    Details
    ISSN: 1432-2072
    Schlagwort(e): LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect of LSD 25 (i. v. injection) on the spontaneous and evoked activity of the visual system was investigated in cats. 50 γ/kg did not change significantly the ERG and the visual cortical evoked potential. The spontaneous discharge rate of 14 out of 21 retinal ganglion cells showed an increase which reached its maximum within 20–30 min and which could still be present 1 hour following the injection. One third of the retinal units showed a slight depression of their spontaneous dischaRge rate with about the same time course. Single units of the LGN showed about the same behaviour. The response to light stimulation was slightly increased in some units and light induced inhibition was slightly shortened. The possible mechanism of the LSD-effect on retinal ganglion cell activity is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403713
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  • 30
    Digitale Medien
    Digitale Medien
    Responses of neurones in cat's abducens nuclei to horizontal angular acceleration (1969)
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single cell activity was recorded extracellularly from neurones in cat's abducens nuclei in unanesthetized, decerebrate preparations. Two types of neurones were found. i) The motoneurones (type IIA) increased their firing linearly or exponentially to contralateral constant angular accelerations and decreased firing to ipsilateral rotation. The increased frequency was maintained at a constant level without any sign of adaptation. This constant level of maximum frequency was proportional to the logarithm of the acceleration applied. No significant differences of the frequency responses of tonic and silent motoneurones were found. The conduction velocities of the axons of spontaneously firing type IIA cells were slower than in silent neurones. Electrical stimulation of the contralateral VIIIth nerve led to activation of the type IIA cells; stimulation of the ipsilateral nerve resulted in inhibition of both spontaneous discharge and antidromic invasion of the motoneurones. ii) The type IA units increased their firing rate to ipsilateral rotation and ceased to discharge in response to contralateral rotation. They never were excited antidromically by stimulation of the VIth nerve. However, they were excited by stimulation of the ipsilateral VIIIth nerve. Their possible functional role in the vestibulo-ocular system was discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00587754
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  • 31
    Digitale Medien
    Digitale Medien
    Die Rolle „spezifischer” und unspezifischer Afferenzen für den Antrieb der Atmung, untersucht durch Reizung und Blockade von Afferenzen an der decerebrierten Katze (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 189-205 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An 11 intercolliculär decerebrierten Katzen wurde geziegt, daß Kälteblockade eines eng umschriebenen Feldes auf der ventralen Oberfläche der Medulla oblongata, wie früher für anaesthesierte Tiere beschrieben, zu Atemstillstand führt, wenn die kontralaterale Stelle auf der Medulla oblongata, die Sinusnerven und die Vagi ausgeschaltet sind. Zu Atemstillstand kam es auch, wenn statt der Kälteblockade 2% Novocain durch lokale Superfusion bei gleichzeitiger Gegenspülung der Umgebung mit künstlichem Liquor angewandt wurde, oder wenn ein mit 1% Novocain getränkter Tupfer lokal aufgelegt wurde. Außerdem führte Kälteblockade zu Atemstillstand, wenn durch kontinuierliche auch während der Kälteblockade anhaltende elektrische Reizung eines N. femoralis oder hinterer Lumbalwurzeln an decerebrierten Katzen oder des Hypothalamus an einer anaesthesierten Katze Steigerungen der Ventilation ausgelöst worden waren. Elektrische Reizung eines Sinusnerven führte zu Atemsteigerungen. Bei Sinusnervenreizung während eines durch Kälteblockade ausgelösten Atemstillstands kam es zu rhythmischer Atmung. Aus diesen Untersuchungen wird geschlossen, daß mit der Ausschaltung der beschriebenen Felder auf der ventralen Oberfläche der Medulla oblongata am sonst desafferentierten Tier die Gesamtheit der für die zentrale CO2-Empfindlichkeit verantwortlichen Strukturen erfaßt ist, daß nach Ausschaltung der zentralen und der peripheren Chemosensibilität eine unspezifische Aktivierung der Atmungszentren unwirksam ist und daß die Atmungszentren zur Ausbildung einer rhythmischen Atmung von spezifischen Antrieben abhängig sind.
    Notizen: Summary It was shown in 11 decerebrated cats, that cooling of a small and well defined area on the ventral surface of the medulla will cause respiratory arrest if the contralateral area of the medulla, the vagi and sinus nerves are eliminated. This confirms earlier observations obtained in anesthetized cats. Apnea was also produced by local superfusion of 2% procain with simultaneous flushing of the immediate surrounding area with mock spinal fluid. Local application of a small sponge soaked with 1% procain had the same effect. Electrical stimulation of femoral nerves or posterior roots which results in hyperventilation on the decerebrated cat failed to show any effect during periods of cold blockade. There was no respiratory response to direct stimulation of the hypothalamus in an anesthetized cat during cooling. Electrical stimulation of one sinus nerve caused an increase of ventilation. Sinus nerve stimulation during apnea induced by cold blockade resulted in rhythmical respiration. It is concluded from these experiments: Blocking of the area under discussion on the ventral surface of the medulla, inhibits all structures responsible for the central CO2-sensitivity in the deafferentiated animal. There was no response to non-specific stimuli of the respiratory center after elimination of central and peripheral chemosensitivity. The respiratory centers apparently depend on specific stimuli to support rhythmical respiration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00586928
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  • 32
    Digitale Medien
    Digitale Medien
    Relevance of sodium transport pool measurements in toad bladder tissue for the elucidation of the mechanism whereby hormones stimulate active sodium transport (1969)
    Springer
    Pflügers Archiv 313 (1969), S. 197-221 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Toad Bladder ; Sodium Transport Pool ; Aldosterone ; Insulin ; Vasopressin ; Krötenblase ; Natrium-Transport-Pool ; Aldosteron ; Insulin ; Vasopressin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The size of toad bladder sodium transport pool, defined as that amount of sodium of apical origin and recovered in tissue at equilibrium, was compared with sodium transport rate, derived from short-circuit current read immediately before tissue analysis. Provided certain precautions be taken, the relationship between both variables can be described by a curve starting at the intersect ofX (pool, in μEq) andY (transport, in μEq/hr) axes, with a tendency forX to increase faster thanY. Assuming sodium transport pool forms one compartment, its calculated half-life averages 2–3 min. sodium transport pool measurements are thought to shed light on mechanism of sodium transport by toad bladder because pool size was large with respect to transport rate when tissue was exposed to several inhibitors of sodium transport. Conversely, upon stimulation of activity of (substrate — depleted) preparations by glucose, a relative reduction of pool size was observed. Aldosterone, vasopressin (and adenosine 3′,5′-phosphate) increased sodium pool size and transport rate, proportionately; insulin stimulated sodium transport more than it increased pool size. Thus, insulin presumably exerts its effect at the sodium “pump” while such a site of action need not be postulated for aldosterone and vasopressin: these 2 hormones would instead induce, permeability changes faciliting sodium movement at the apical border of toad bladder epithelial cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00586744
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  • 33
    Digitale Medien
    Digitale Medien
    Defence, attack, and flight elicited by electrical stimulation of the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Affective behaviour patterns produced by electrical stimulation of the hypothalamus were studied in unanaesthetized, freely-moving cats. Bipolar stimulation with coaxial electrodes and small cathode was used to elicit defence, attack or flight. The development of these responses was studied by varying stimulation strength. In some experiments a stuffed animal was introduced in order to study the reactions of the cat to changes in the environment during stimulation. 2. The following responses were evoked at threshold intensity: (i) growling reaction; (ii) hissing reaction; (iii) two types of flight — type a preceded by hastily looking to and fro as if in search of an exit, type b preceded by inspection of surroundings, in most cases associated with sniffing. 3. Increasing stimulation 1.5 times threshold often yielded combined patterns. At points yielding the growling reaction a defence response in which growls alternated with hisses was obtained. The points yielding flight type a sometimes yielded hissing followed by flight. Increasing stimulation at hissing points yielded either a defence reaction or the combined effect hissing-flight. 4. The growling reactions were obtained from the tuber region. The hissing responses were obtained from points above the tuber. The flight reactions, type a, were produced from the intermediate zone extending from the level of the preoptic area to the mamillary bodies and type b from the caudo-lateral hypothalamus. 5. The reactions of the cats to a dummy during stimulation varied depending on the type of response which had been evoked in the absence of the dummy. The defence reaction was converted into threatening and striking of the dummy, the combined effects into threatening, striking or biting, culminating in sudden flight. The dummy was ignored during stimulation of points yielding flight type a, but examined by sniffing during stimulation of points yielding flight type b.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234534
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  • 34
    Digitale Medien
    Digitale Medien
    Evidence for mediated transport of chloride in cat cerebral cortex in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The kinetics of the uptake of chloride by slices of cat cerebral cortex incubated in vitro have been studied for a wide range of concentrations of chloride and potassium in the incubation media. 1. In studies with 36Cl at a constant concentration of external K+, the rate of entry of chloride into slices of cat cerebral cortex (after equilibration with the fluid of the extracellular space) followed Michaelis-Menten kinetics with Vmax=7.7 μmoles/g/min and Km=245 mM. The kinetic data so described differ significantly from a curve describing simple diffusion (P 〈 0.02). 2. A clear dependence on concentration of K+ in the incubation medium was demonstrated. When external chloride was held constant at 6.8 mM and concentrations of potassium were varied over a range of 27–100 mM, the apparent rate of entry of chloride followed Michaelis-Menten kinetics with Vmax=0.191 μmoles/ g/min and Km=30.3 mM. 3. Under similar equilibrium conditions, the rate of influx of chloride was not statistically different from the rate of efflux, and the value for extracellular space (355 μl/g) derived by extrapolation from efflux data was of an identical order of magnitude to the value (352 μl/g) obtained from influx data. These values are essentially identical to those previously determined for chloride space of cat cerebral cortex in vivo (Bourke, Greenberg and Tower 1965). 4. The total, membrane-delimited content of chloride in cerebral cortex, as defined in these studies in vitro, was a function of the concentration of K+ in the incubation medium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234250
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  • 35
    Digitale Medien
    Digitale Medien
    Studies of the development and subsequent reduction of swelling of mammalian cerebral cortex under isosmotic conditions in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ionic parameters of incubation media which foster both the development and subsequent reduction of swelling of slices of cerebral cortex under isosmotic conditions of incubation in vitro are described. A linear relationship between increasing chloride concentrations in incubation media and progressive swelling of tissue slices (under conditions of constant temperature and K+ concentrations and isotonicity of incubation media) is demonstrated. Subsequent reduction of chloride concentration in incubation media together with reciprocal replacement by isethionate is associated with significant and characteristic reduction in the volume of tissue swelling when all other conditions of incubation, including isotonicity of the media, are kept constant. The ionic composition of the fluid of swelling under different conditions of incubation is derived together with the ionic composition and expected transmembrane potentials of the neuronal compartment of cerebral cortex in vitro. Mechanisms involved in the development and subsequent reduction of swelling of cerebral cortex in vitro are discussed, and proposals for possible clinical applications are suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234251
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  • 36
    Digitale Medien
    Digitale Medien
    Verbesserung der Resorption von Helveticosid und Helveticosol durch Substitution der Hydroxylwasserstoffe an der Digitoxose (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde die Wirksamkeit verschiedener Ester und Äther von Helveticosid und Helveticosol bei i.v. und intraduodenaler Zufuhr an Katzen und Meerschweinchen geprüft. 1. Bei i.v. Dauerinfusion waren Helveticosol und seine Derivate bei Meerschweinchen etwa doppelt so wirksam wie die analogen Helveticosidverbindungen. Bei der Katze bestand kein Unterschied. Die Monomethyläther Cymarin und Cymarol waren gleich oder sogar stärker wirksam, alle übrigen Derivate deutlich schwächer als die Ausgangssubstanzen. 2. Die tödlichen Dosen bei intraduodenaler Injektion lagen beim Meerschweinchen für einige Substanzen in gleicher Größenordnung oder niedriger als die Titer bei i.v. Infusion. Diese hohe enterale Wirksamkeit kann bei Helveticosid und seinen Derivaten durch eine Reduktion zu dem wirksameren Helveticosol, bei Estern außerdem durch eine Hydrolyse zu wirksameren Glykosiden vorgetäuscht werden. 3. Bei intraduodenaler Infusion an Katzen waren alle geprüften Ester und Äther wirksamer als Helveticosid und Helveticosol. Die aus dem Verhältnis der toxischen Dosen bei i.v. und intraduodenaler Infusion berechnete enterale Wirksamkeit lag zwischen 20 und 50%. 4. Unterschiede in der Dauer der intraduodenalen Infusion bei Katzen lassen sich berücksichtigen, wenn man von der theoretischen Annahme einer exponentiellen und vollständigen Resorption ausgeht und die Halbwertszeit für die Resorption berechnet. Die minimale Resorptionsgeschwindigkeit lag bei einigen Derivaten in gleicher Größenordnung wie bei Digoxin und Digitoxin. Es wird auf den Unterschied zwischen der auf Grund der pharmakologischen Wirkung bestimmten relativen enteralen Wirksamkeit und der Resorptionsquote hingewiesen. Letztere ist für die Verläßlichkeit der therapeutischen Wirkung eines Glykosids bei oraler Gabe maßgebend.
    Notizen: Summary The efficacy of several esters and ethers of Helveticosid and Helveticosol was assayed by intravenous and intraduodenal administration to cats and guinea-pigs. 1. In guinea-pigs, Helveticosol and its derivatives were approximately twice as active on intravenous infusion as the analogous derivatives of Helveticosid; in cats there was no significant difference. The monomethylethers Cymarin and Cymarol were equally or slightly more potent, all other derivatives were weaker than the original compound. 2. In guinea-pigs the lethal doses of some compounds on intraduodenal injection were equal to or even lower than those on intravenous infusion. This may partly be accounted for by a reduction of Helveticosid and its derivatives to the more potent Helveticosol analogues, partly by a hydrolysis of the esters, yielding compounds of higher activity. 3. On intraduodenal infusion in cats, all the investigated esters and ethers were more active than Helveticosid and Helveticosol. The relative enteral activity calculated from the ratio of the toxic doses on intravenous and intraduodenal infusion varied between 20 and 50%. 4. Due to a delayed absorption from the gastrointestinal tract, the toxic dose falls with a reduced speed of intraduodenal infusion. Assuming an exponential and complete absorption, the half time of absorption was calculated. For some of the compounds investigated, the speed of absorption was comparable to that of Digoxin and Digitoxin. The difference between the relative enteral activities determined by comparing equiactive doses on enteral and parenteral administration and the percentages of the glycosides which are absorbed from the gastrointestinal tract is pointed out. The latter is of prime importance for obtaining reproducible effects after enteral administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00536819
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  • 37
    Digitale Medien
    Digitale Medien
    Procedure for double antibody immunoassay of insulin (1969)
    Springer
    Acta diabetologica 6 (1969), S. 371-388 
    Details
    ISSN: 1432-5233
    Schlagwort(e): Insulin ; Insulin antibodies ; Insulin assay ; Laboratory technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01548060
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  • 38
    Digitale Medien
    Digitale Medien
    Variaciones diurnas de la eliminación de insulina en orina (1969)
    Springer
    Acta diabetologica 6 (1969), S. 197-205 
    Details
    ISSN: 1432-5233
    Schlagwort(e): Diurnal variations ; Food intake ; Glucose load ; Insulin ; Tolbutamide test
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Resume On a étudié l'effet de la lumière et de la période d'ingestion des aliments sur l'élimination d'insuline par les urines. On peut démontrer l'existence d'un rythme circadien et la présence de deux facteurs de régulation pour cette élimination. On présente quelques hypothèses concernant ces phénomènes.
    Kurzfassung: Resumen Se estudió el efecto que sobre la eliminación de insulina urinaria ejercen los períodos de luzoscuridad y el horario de administración del alimento. Se demuestra la existencia de un ritmo circadiano de eliminación de dicha hormona, describiéndose dos reguladores del mismo. Se hacen especulaciones fisiopatológicas acerca de su significado.
    Notizen: Riassunto E' stato studiato l'effetto della luce e del periodo di ingestione del cibo sull'eliminazione di insulina nelle urine. Si può dimostrare l'esistenza di un ritmo circadiano e la presenza di due fattori di regolazione per questa eliminazione. Vengono presentate alcune ipotesi concernenti questi fenomeni.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01548049
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  • 39
    Digitale Medien
    Digitale Medien
    Proprietà insulino-stimolanti della glibenclamide (HB 419) in soggetti normali. Studi comparativi con la tolbutamide (1969)
    Springer
    Acta diabetologica 6 (1969), S. 283-298 
    Details
    ISSN: 1432-5233
    Schlagwort(e): Glybenclamide ; Insulin ; Insulin secretion ; Sulfonylureas ; Tolbutamide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Resume Les effets métaboliques de la glybenclamide et de la tolbutamide ont été étudiés chez deux groupes de sujets normaux traités avec des doses comparables des deux sulphanylurées. En rapport aussi à la dose de 1:400, la glybenclamide a démontré une activité insuline-sécrétive bien majeure de celle de la tolbutamide. La réponse insulinique a été suivie par une rapide et prolongée diminution des NEFA sériques et par un moins persistant effet hypoglycémique. Les effets métaboliques de l'HB 419 sont encore évidents 10–12 heures après l'administration du médicament, tandis que l'activité de la tolbutamide est terminée géneralement entre 4–6 heures. Quand l'administration des médicaments a été pratiquée en concomitance avec une charge veineuse de glucose, le coéfficient de Conard était élevé d'une façon significative par toutes les deux sulphanylurées.
    Kurzfassung: Resumen Los efectos metabólicos de la glibenclamida y de la tolbutamida han sido investigados en dos grupos de sujetos normales tratados con dosis comparables de las dos sulfanilúreas. Inclusive en una relación de dosificación de 1:400, la glibenclamida ha demostrado una actividad insulinosecretora mucho mayor de la tolbutamida. La respuesta insulínica ha sido seguida de una disminución pronta y prolongada de los NEFA séricos y de un efecto hipoglucemiante menos persistente. Los efectos metabólicos del HB 419 son aún evidentes a las 10–12 horas después de la administración del medicamento, mientras la actividad de la tolbutamida es anulada por lo general dentro de 4–6 horas. Cuando la suministración de los medicamentos ha sido practicada en coincidencia con una carga venosa de glucosa, el coeficiente de Conard apareció significativamente elevado por ambas sulfanilúreas.
    Notizen: Riassunto Gli effetti metabolici della glibenclamide e della tolbutamide sono stati indagati in 2 gruppi di soggetti normali trattati con dosi comparabili delle due sulfaniluree. Anche in un rapporto di dosaggio di 1:400, la glibenclamide ha mostrato un'attività insulino-secretiva assai maggiore di quella della tolbutamide. La risposta insulinica è stata seguita da una pronta e prolungata diminuzione dei NEFA serici e da un meno persistente effetto ipoglicemico. Gli effetti metabolici del-l'HB 419 sono ancora evidenti 10–12 h dopo la somministrazione del farmaco mentre l'attività della tolbutamide si annulla generalmente entro 4–6 h. Quando la somministrazione dei farmaci è stata praticata in coincidenza con un carico venoso di glucosio, il coefficiente di Conard è apparso significativamente innalzato da entrambe le sulfaniluree.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01548054
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  • 40
    Digitale Medien
    Digitale Medien
    Studies on the transport of insulin antibodies across the placenta to the fetus and their effect on the fetal pancreatic islet system (1969)
    Springer
    Acta diabetologica 6 (1969), S. 573-584 
    Details
    ISSN: 1432-5233
    Schlagwort(e): Insulin ; Insulin antibodies ; Islets of Langerhans ; Placenta ; Transport
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Resume Ce travail est la continuation des communications préliminaires sur la résistance insulinique des nouveaux-nés de mères insuline-résistantes. Les recherches ont été conduites sur cobayes et sur sujets humains. Les AA. ont démontré que les anticorps anti-insuline passent dans la circulation fœtale et provoquent l'apparition d'une insuline-résistance passive qui va disparaître dans les premières semaines de la vie. Les anticorps contre l'insuline bovine lient en partie l'insuline endogène des cobayes, ce qui est mis en evidence par l'hyperglycémie élevée des cobayes jeunes nées de mères insuline-résistantes. Les anticorps anti-insuline n'ont aucun effet important sur la structure du pancréas des cobayes dans la période périnatale.
    Kurzfassung: Resumen Este trabajo representa la continuación de las comunicaciones preliminares sobre la resistencia insulínica que presentan las personas nacidas de madres insulino-resistentes. Las investigaciones han sido efectuadas en cobayas y hombres. Se ha demostrado que los anticuerpos anti-insulina pasan al círculo fetal, provocando la aparición de insulino-resistencia pasiva, que desaparece durante las primeras semanas de vida. Los anticuerpos contra la insulina bovina ligan en parte la insulina endógena de cobayas, como lo demuestra la hiperglucemia elevada de las cobayas jóvenes nacidas de madres insulino-resistentes. Los anticuerpos anti-insulina no ejercen ningún efecto apreciable sobre la estructura del páncreas de las cobayas durante el período peri-natal.
    Notizen: Riassunto Questo lavoro rappresenta la continuazione delle comunicazioni preliminari sulla resistenza insulinica dei nati di madri insulino-resistenti. Le ricerche sono state condotte su cavie e su uomini. E' stato dimostrato che gli anticorpi anti-insulina passano nel circolo fetale inducendovi la comparsa di una insulino-resistenza passiva che scompare nelle prime settimane di vita. Gli anticorpi contro l'insulina bovina legano in parte l'insulina endogena di cavie, come è evidenziato dall'elevata iperglicemia delle cavie giovani nate da madri insulino-resistenti. Gli anticorpi anti-insulina non esercitano alcun effetto di rilievo sulla struttura del pancreas delle cavie nel periodo perinatale.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01548073
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  • 41
    Digitale Medien
    Digitale Medien
    Insulin allergy. Clinical and immunological effects of specific desensitization (1969)
    Springer
    Acta diabetologica 6 (1969), S. 796-808 
    Details
    ISSN: 1432-5233
    Schlagwort(e): Desensitization ; Immunoglobulins ; Insensitivity ; Insulin ; Insulin allergy ; Insulin antibodies ; Macroglobulins ; Porcine insulin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Resume Cinq patients atteints d'allergie à l'insuline ont été désensibilisés par de l'insuline de porc selon la méthode d'Urbach et Gotlieb. Le diagnostic d'allergie à l'insuline a été posé sur la base des manifestations cliniques, de la positivité des réactions cutanées et, dans 2 cas, des réactions de Prausnitz-Küstner (P.K.). On a obtenu dans 3 cas une désensibilisation. La présence d'anticorps anti-insuline a été révélée par la méthode immunoautoradiographique en employant de l'insuline131J. Avant la désensibilisation la présence d'anticorps IgG a été enregistrée chez 3 patients tandis que chez 2 on a démontré également des anticorps IgA. Une réaction de P.K. positive a été observée chez des patients dont les sérums contenaient des anticorps IgA. Pendant la désensibilisation on a observé une apparition transitoire de macroglobulines capables de lier l'insuline131J. Après la désensibilisation on a constaté la persistance de la positivité aux réactions cutanées immédiates à l'insuline de porc et de boeuf. En même temps les réactions retardées et la réaction de P.K. à l'insuline de porc étaient interverties, bien que les mêmes réactions à l'insuline bovine restaient positives.
    Kurzfassung: Resumen Cinco pacientes que padecían de alergia a la insulina han sido desensibilizados con insulina porcina según el método de Urbach y Gotlieb. El diagnóstico de alergia a la insulina ha sido puesto teniendo en cuenta las manifestaciones clínicas, el positivismo de las reacciones cutáneas, y, en 2 casos, las reacciones de Prausnitz-Küstner (P.K.). En 3 casos se ha obtenido desensibilización. La presencia de anticuerpos anti-insulina ha sido puesta en evidencia con el método inmunoautoradiográfico, empleando insulina131J. Antes de la desensibilización, la presencia de anticuerpos IgG ha sido hallada en 3 pacientes, mientras que en 2 han sido demostrados también anticuerpos IgA. Una reacción de P.K. positiva ha sido observada en pacientes cuyos sueros contenían anticuerpos IgA. Durante la desensibilización se ha observado aparición transitoria de macroglobulinas capaces de ligar la insulina131J. Al cabo de la desensibilización se ha notado la persistencia del positivismo a las respuestas cutáneas inmediatas a la insulina porcina y bovina. Al mismo tiempo, las respuestas retardadas y la reacción de P.K. a la insulina porcina cstaban invertidas, no obstante que las mismas reacciones a la insulina bovina hubieran quedado positivas.
    Notizen: Riassunto Cinque pazienti con allergia all'insulina sono stati desensibilizzati con insulina suina secondo il metodo di Urbach e Gotlieb. La diagnosi di allergia all'insulina è stata posta sulla base delle manifestazioni cliniche, della positività delle reazioni cutanee e, in 2 casi, delle reazioni di Prausnitz-Küstner (P.K.). In 3 casi si è ottenuta una desensibilizzazione. La presenza di anticorpi anti-insulina è stata rivelata con il metodo immunoautoradiografico impiegando insulina131J. Prima della desensibilizzazione la presenza di anticorpi IgG è stata riscontrata in 3 pazienti mentre in 2 sono stati dimostrati anche anticorpi IgA. Una reazione di P.K. positiva è stata osservata in pazienti i cui sieri contenevano anticorpi IgA. Durante la desensibilizzazione si è osservata una comparsa transitoria di macroglobuline capaci di legare l'insulina131J. Dopo la desensibilizzazione si è riscontrata la persistenza della positività delle risposte cutanee immediate all'insulina suina e bovina. Al tempo stesso le risposte ritardate e la reazione di P.K. all'insulina suina erano invertite, sebbene le stesse reazioni all'insulina bovina rimanessero positive.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01548086
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  • 42
    Digitale Medien
    Digitale Medien
    Morphologische Untersuchungen an der Glandula bulbourethralis der Katze (1969)
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glandula bulbourethralis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Parenchym der Glandula bulbourethralis der Katze besteht aus weitlumigen, gebuchteten intraglandulären Gängen, in welche kurze, englumige, zumeist unverzweigte Tubuli einmünden. Der Drüse fehlt eine äußere Organkapsel, so daß ihre peripheren Tubuli stellenweise direkt zwischen den Fasern des quergestreiften M. bulboglandularis liegen. Die Drüsentubuli und die Buchten der intraglandulären Gänge sind mit einem einschichtigen Zylinderepithel ausgekleidet, auf den Gangfalten ist das Epithel abschnittsweise mehrreihig, Die sezernierende Epitheloberfläche ist durch die Ausbildung von interzellulären Sekretkapillaren vergrößert. Breite Zwischenzellspalten (Durchmesser etwa 1,5μ), in welche schlanke interdigitierende Cytoplasmafortsätze hineinragen, erstrecken sich von der Basalmembran bis kurz unter das Tubulusbzw. Ganglumen. Die lumenseitigen Zellgrenzen tragen einige stummelförmige Mikrovilli und besitzen zerklüftete Außenkonturen, die durch glykogenreiche Cytoplasmaprojektionen bedingt sind. Alle Epithelzellen sind reich an Mitochondrien. Die supranuklearen Abschnitte der meisten Gang- und Tubuluszellen enthalten Sekretgranula, welche im Elektronenmikroskop unterschiedliche optische Dichten aufweisen können. Die Granula enthalten ein PAS-positives, neuraminsäurehaltiges epitheliales Muzin, das in einzelnen Sekretkörnchen auch eine histochemische Reaktion auf Sulfatgruppen gibt. Alle Epithelzellen reagieren sehr stark auf unspezifische Esterase und stark auf β-D-Glucuronidase, β-D-Glactosidase sowie die Enzyme des Citronensäurezyklus, der Glykolyse und der Atmungskette (NAD-ICDH, SDH, ALD, LDH, ADH, GDH, NADH-T-Red, Cyt-Ox).
    Notizen: Summary The bulbourethral glands of sexually mature male cats are studied with the light and electron microscope. The parenchyma consists of spacious, sinus-like intraglandular ducts and short, narrow, mostly unbranched tubular endpieces. The gland has no complete connective tissue capsule, consequently some of the peripheral tubules are situated directly in between the fibers of the surrounding bulboglandularis muscle. The endpieces and the sinus of the intraglandular ducts are lined by a simple columnar epithelium, whereas the folds of the ducts are generally covered by a low pseudostratified epithelium. The secretory surface of the cells is increased by intercellular canaliculi which communicate with the gland lumen. These canaliculi are identified on the light microscopic level by their strong 5′-nucleotidase activity. Furthermore widened intercellular spaces (approximately 1,5 μ in diameter) filled with slender, interdigitating cytoplasmic processes extend from the basal lamina to the apical junctional complexes. The luminal cell pole exhibits some short microvilli and forms irregularly shaped, glycogen containing protrusions. Within the cytoplasm of the gland cells numerous spherical mitochondria, some dense bodies, a typical Golgi apparatus, free ribosomes and a poorly developed endoplasmic reticulum are to be observed. Secretory granules which can be grouped into three types on the basis of their electron density occur in the supranuclear regions of most of the cells. According to histochemical tests all granules contain a periodate reactive sialomucin and some of them also sulfate groups. The glandular parenchyma is site of an exceptionally strong unspecific esterase activity and is rich in β-D-glucuronidase, β-D-glactosidase, aldolase, α-glycerophosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and cytochrome oxydase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335273
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  • 43
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080101
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  • 44
    Digitale Medien
    Digitale Medien
    Influence of temperature on the helix sense of several polyamino acids (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 21-27 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An increase in temperature causes an increase in the amplitudes of intramolecular and intermolecular motions and mainfests itself as an increase in the effective radii of the various atoms, especially hydrogen atoms. If one uses a Lennard-Jones 6-12 potential function to account for nonbonded interactions, this increase in the radius of the hydrogen atom is equivalent to a modification of the coefficient of the repulsive part of the Lennard-Jones potential. Accordingly, this effect of increasing temperature on the helix sense of several polyamino acids is computed by allowing the effective radius of the hydrogen atom to increase. It is found that the preferred sense of several polyamino acid helices changes from right- to left-handed as the temperature is increased. This accounts for recent experimental observations of changes in helix sense with temperature.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080103
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  • 45
    Digitale Medien
    Digitale Medien
    Helix-coil transition for poly(L-glutamic acid) in water-ethanol solutions (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 57-68 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Potentiometric titrations and some complementary optical rotation data are presented for solutions of poly(L- glutamic acid) (PGA) in several H2O-ethanol mixtures. The data allow the determination of the intrinsic pK (pK0), slope of the apparent. pK (pKapp), versus degree of ionization curves and of the enthalpy of ionization as a function of ethanol concentration. The variation of the degree of ionization at which the helix-coil transformation occurs with ethanol and temperature is also determined. Finally free energy, enthalpy, and intropy changes associated with the helix-coil transformation for the uncharged conformers are determined from the titration curves. The effect of the ethanol is to increase the stability of the helical conformation of PGA for both the charged and the uncharged forms of the polymer. The stabilization of the uncharged helix is essentially an entropic effect.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080106
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  • 46
    Digitale Medien
    Digitale Medien
    Low-frequency infrared bands and chain conformations of polypeptides (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 91-99 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Infrared spectra of polypeptides were measured in the region of 1800-400 cm-1. For the α-helical form, disordered form, and antiparallel-chain β-form, amide V band- arising from N-H out-of-plane bending models were observed at 610-620, around 650, and 700-705 cm-1, respectively, and amide V′ bands arising from N-D out-of-plane bending modes were observed at 455-465, around 510, and a 515-530 cm-1, respectively. These correlations are useful for conformation diagnoses, particularly for copolyamino-acids or proteins which are not oriented. The nature of low-frequency amide bands are discussed with reference to potential energy distributions calculated for the α-helical form and β form.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080108
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  • 47
    Digitale Medien
    Digitale Medien
    Etude, par spectroscopie infra-rouge, de la conformation de quelques composés peptidiques modèles (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 69-89 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Some experimental data are given on the infrared spectra between 3300 and 3500 cm-1 of dilute solutions in carbon tetrachloride of three types of model compounds: CH3-CONH-CH(R1)-CONH(R2), (I); CH3-CON(CH3)-CH(R1)-CONH(R2), (II) and CH3-CONH-CH(R1)-CON(R2)2, (III). In studying the N-H stretching bands, it was found that there are two types of intramolecular hydrogen bonds in these molecules; these result in two different cyclized conformations, C5 and C7, which contain respectively, five and seven atoms in the ring. By using model substances I, II, and III, in which the nitrogen atoms are unequally substituted, it is possible to identify the N-H stretching bands which are to be ascribed to the N-H oscillators included in the two different chelated conformations. It is found also that the stretching frequency of a free N-H oscillator depends upon the substituent on the nitrogen atom. Thus, it is possible to observe, with some of the model compounds I, four different absorption bands located at 3340, 3420, 3440, and 3460 cm-1. The first two are ascribed to the N-H oscillators included in the H—bonds which lock the C7 and C5 conformations; the last two correspond to free N-H which differ with the substituent on the nitrogen atom.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080107
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  • 48
    Digitale Medien
    Digitale Medien
    Interaction of poly-L-lysine with nucleic acids. V. Effect of salt concentration (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 153-155 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080112
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  • 49
    Digitale Medien
    Digitale Medien
    Quantum mechanical approach to the conformational analysis of macromolecules in ground and excited states (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 207-213 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Molecular orbital calculations of the extended Hückel type have been used to study the conformations of glycyl and alanyl residues in ground and excited states. The ground-state surfaces show features similar to those obtained with the standard calculational methods in which the total energy is partitioned into components such as torsions, nonbonded and electrostatic interactions. The molecular orbital calculations provide the first independent theoretical check on such calculations. The excited-state surfaces, Uniquely available from the molecular orbital calculations, exhibit a better definition and sharpening of potential minima in the sterically allowed regions.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070207
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  • 50
    Digitale Medien
    Digitale Medien
    Computation of molecular weight averages for DNA molecules containing both preformed and randomly induced single-strand breaks (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 215-221 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We derive equations for calculating the number-, weight-, and z-average lengths between single-strand breaks in DNA molecules. Provision is made for the existence of preformed breaks under genetic control: these are assumed to be fixed in number in each molecule, but may be variable in position. Breaks due to random degradation may be superimposed on the pre-existing breaks. An example is given for illustrative purposes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070208
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  • 51
    Digitale Medien
    Digitale Medien
    Studies on the secondary structure of ribosomal ribonucleic acid components of rabbit reticulocytes (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 223-239 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The conformation in solution of fractionated 30 S and 19 S ribosomal RNA from rabbit reticulocytes has been studied by optical rotatory dispersion, analysis of thermal melting profiles and their derivatives, and spectrophotometric acid-base titration. From a consideration of the limitations of these methods, it has been possible to set limiting values on the degree of base-pairing and the lengths of the double helices: between 60 and 80% of the bases in 19 S and 30 S RNA are estimated to be paired. The paired segments are not shorter than 4 base pairs, and evidence from other sources is available which indicates that they are not longer than 8-16 base pairs. The spread of helix lengths is greater in the 30 S than in 19 S RNA; and other differences are noted. Several distinct populations of double helices, differing in their thermal stability, are present. Estimates are presented from spectrophotometric and titration data for the base compositions of the paired and unpaired regions.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070209
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  • 52
    Digitale Medien
    Digitale Medien
    Instability in diffusing fluid layers (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 251-263 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A small perturbation analysis is carried out to determine the stability of a fluid containing two layers of diffusing solutes in a common solvent and acted upon by a uniform gravitational field. It is found that instability can arise even though the unperturbed diffusion does not lead to the formation of a density inversion within the fluid.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070211
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  • 53
    Digitale Medien
    Digitale Medien
    Abbreviated nomenclature of synthetic polypeptides (polymerized amino acids). Tentative rulesDocument of the IUPAC-IUB Commission on Biochemical Nomenclature (CBN), approved by IUPAC and IUB in October, 1967, and published by permission of the International Union of Pure and Applied Chemistry, the International Union of Biochemistry, and the official publishers of IUPAC, Messrs. Butterworths Scientific Publications. (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 161-166 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080202
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  • 54
    Digitale Medien
    Digitale Medien
    Kinetics of denaturation of DNA (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 475-493 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The kinetics of denaturation of DNA have been studied by relaxation techniques. Examination of the terminal relaxation times for a variety of DNA's under a variety of conditions has shown that DNA denaturation is principally a hydrodynamically limited process. Measurements within the helix-coil transition have demonstrated that the experimentally measured terminal relaxation times are a function of the following: (1) position in the helix-coil transition; (2) ionic strength of the solvent; (3) solvent viscosity; (4) DNA concentration; (5) molecular weight; (6) number and position of single-strand breaks. The dependence of the terminal relaxation time on the above mentioned factors can be attributed to hydrodynamic effects. Thus a hydrodynamic model for DNA unwinding is required. The model which best fits the data involves the assumption of a rotational frictional coefficient independent of molecular weight. This assumption is suggested by the fact that the relaxation time is proportional to the first power of the molecular weight.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070406
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  • 55
    Digitale Medien
    Digitale Medien
    Counterion binding in partially neutralized poly(D-glutamic acid) and poly(DL-glutamic acid) (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 495-502 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Sodium counterion association with partially neutralized poly(D-glutamic acid) or poly(DL-glutamic acid) was measured by use of Wall's transference method with radioactive sodium. In the region where both polyacids are in completely random coil form, fractions of association were considerably less than that with poly(acrylic acid) in the same region of degree of neutralization. Even in the region where poly (D-glutamic acid) is in the helical form, the fraction of association was less than that with poly(acrylic acid) in the same region. No pronounced characteristics attributable to counterion association corresponding to the helix-coil transition could be found. The association phenomena were discussed on the basis of a rodlike model of polyelectrolyte.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070407
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  • 56
    Digitale Medien
    Digitale Medien
    NMR studies in solution of poly-L-proline (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 411-415 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The isomerization of poly-L-proline in different solvents has been studied by NMR spectroscopy. Different resonance signals for the CHα protons have been obtained for the two different helical conformations of thus compound, namely form I and form II.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070311
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  • 57
    Digitale Medien
    Digitale Medien
    Synthesis of poly-L-asparagine and poly-L-glutamine (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 417-422 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Poly-β-N-diphenylmethyl-L-asparagine and poly-γ-N-diphenylmethyl-L-glutamine were prepared from the corresponding N-carboxyanhydrides. Poly-L-aspuragine and poly-L-glutamine were obtained by removal of the diphenylmethyl protecting groups with liquid anhydrous hydrofluoric acid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070312
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  • 58
    Digitale Medien
    Digitale Medien
    Hydrogen-tritium exchange of the random chain polypeptide (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 379-393 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Hydrogen-tritium exchange character of poly-D,L-alanine was studied in detail as a model for the hydrogen exchange behavior of the unhindered, polymeric peptide group. The random chain nature of poly-D,L-alanine was evident in the uniformity of exchange rate of all its hydrogens and in the similarity between this rate and that of random chain poly-D,L-lysine and other known, unhindered secondary amide groups. An equilibrium isotope effect favoring the binding of tritium over protium to the extent of 21% was measured. Specific acid and base catalysis of the exchange and the absence of detectable general catalysis were demonstrated. Apparent energy of activation is 17 kcal/mole for deprotonation, largely due to dependence of Kw on temperature, and 15 kcal/mole for protonation, which correlates with the extreme apparent pK. The hydrogen -tritium exchange half-time rate; of poly-D,L-alamine at any pH and temperature (T: °C) is given by the equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ \[t_{\frac{1}{2}} \,(\min )\, = \,200\,\, \times \,10^{0.05{\rm T}} /\,[10^{{\rm pH} - 3} \, + \,10^{3 - {\rm pH}} ]\] $$\end{document}
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070309
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  • 59
    Digitale Medien
    Digitale Medien
    Optical rotation of some α-1,4-linked glucopyranosides in the system H2O-DMSO and solution conformation of amylose (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 581-593 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The specific rotation of starch components, corrected for refractive index variation, exhibits a discontinuity in the region of the water-dimethyl sulfoxide (H2O-DMSO) system that corresponds to the composition of the complex 2H2O-DMSO. This discontinuity is a property dependent upon the presence of a number of consecutively linked α-1,4 glucose units and, therefore, must reflect a change in symmetry of a segment, of polymer chain. The optical rotation of amylose between 26.5 and 92.5°C. does not change in DMSO and is only slightly lowered in water at the higher temperature. The behavior of amylose in both DMSO and H2O is like that of a random coil, as indicated by viscosity and sedimentation measurements. These results may be interpreted either as being compatible with models of amylose in solution in which the polymer backbone has helical twist, or as indicating removal of strong interactions between polymer chain segments by a good solvent.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070414
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  • 60
    Digitale Medien
    Digitale Medien
    Calorimetric investigation of the influence of polymer concentration on the transition enthalpy in the helix-coil transition of the double-stranded helical complex poly(A + U) (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 611-613 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070416
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  • 61
    Digitale Medien
    Digitale Medien
    Polarized ultraviolet absorption spectra and electronic transitions of poly-L-proline (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 614-618 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070417
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  • 62
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070101
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  • 63
    Digitale Medien
    Digitale Medien
    John Warren Williams (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 1-3 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070102
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  • 64
    Digitale Medien
    Digitale Medien
    Chemically reacting systems of the type A + B ⇄ AB. II. Osmometry (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 5-19 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The osmotic pressure equation for nonideal, associating systems of the type nA +mB ⇄ AnBm, has been derived, by using the assumption yAnBm/yAnyBm = 1. This treatment can also be applied to related associations such as nA + mB ⇄ AB + AB2 + A2B + …. From osmotic pressure experiments on the pure reactants it is possible to obtain the molecular weights (MA and MB) of the reactants and also the virial coefficients (BAA and BBB) of the reactants. The osmotic pressure of a nonreacting mixture of A and B can be calculated from these measurements. It can be used along with osmotic pressure measurements on equilibrium mixtures of A and B to obtain expressions containing the equilibrium constant (or constants) and the cross-virial coefficients (BAB and BBA). Several procedures are described for the evaluation of the equilibrium constant (or constants) and the BAB or BBA terms. It appears that this procedure is a general one which is applicable to associations of the type nA + mB ⇄ AB + A2B + AB2 + …. By correcting for nonideal behavior, one should then be able to apply it to any method available for analyzing ideal associations of the types considered here. In addition it is possible, subject to certain restrictions, to analyze associations of the type 3A + B ⇄ A2 + AB.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070103
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  • 65
    Digitale Medien
    Digitale Medien
    Differential elution of histones from gel-trapped nuclei (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 39-58 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method has been developed for characterizing at, submicrogram levels the heterogeneity of histones from purified nuclei. The histones are eluted with a smooth concentration gradient from nuclei trapped in polyacrylamide-gel threads and are collected in a micro fraction collector suitable for volumes in the 10-100 μl range. The gradient and fraction collection systems are governed by cam driven syringes. Samples obtained are subjected to electrophoresis in a starch-gel system and the gels are stained with a highly sensitive stain specific for guanidinium groups. Seven major and a similar number of minor components are demonstrated in the histones. The method of differential elution of trapped macromolecules is suitable for use with systems other than nuclei and histones.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070105
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  • 66
    Digitale Medien
    Digitale Medien
    Evaluation of lipoprotein size-density distributions from sedimentation coefficient distributions obtained at several solvent densities. I. Theory (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 119-132 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method is presented for the treatment of distribution functions obtained by ultra-centrifugal sedimentation velocity experiments on the plasma lipoproteins, so that adequate corrections can he made for the effects of diffusion and concentration dependence of the sedimentation coefficient. The method involves the use of modified equations derived from those presented in 1952 by Gosting for the transform from g* (S) to g(S) distributions. The evaluation of the molecular parameters of lipoprotein density and size, from a set of g(Si°) distribution functions obtained in solvents of varying density, is also outlined. Preparations of the β-lipoprotein of human plasma are found to follow a bivariate normal distribution that requires evaluation of five parameters, x̄1, σ1, x̄2, σ2and p. The first two represent the mean and standard deviation of the lipoprotein density, the third and fourth the same quantities for the size, expressed as ft “logarithmic diameter parameter”, and the final value is a measure of the correlation between these two variables.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070112
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  • 67
    Digitale Medien
    Digitale Medien
    Conformations of poly-L-valine in solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 133-133 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070114
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  • 68
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070201
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  • 69
    Digitale Medien
    Digitale Medien
    Nuclear magnetic resonance investigation of the helix to random coil transformation in poly-α-amino acids. I. Poly-L-alanine (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 155-171 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: High-resolution nuclear magnetic resonance spectra at 100 MHz and 220 MHz have been obtained on two samples of poly-L-alanine of differing molecular weights (2500 and 42 500) in the chloroform-trifluoroacetic acid system under various conditions of solvent composition, temperature, and polypeptide concentration. Separate helix and random coil peaks are observed for the α-CH and peptide NH backbone proton resonances, thereby permitting the determination of helix content. This observation of separate peaks demonstrates that the lifetimes of the helix and random coil portions of poly-L-alanine have lower limits of about 10-1 sec. It is suggested that solvent-peptide versus peptide-peptide hydrogen bond competition, coupled with a destabilizing effect of the trifluoroacetic acid on the helix, is responsible for the helix-random coil transformation.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070203
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  • 70
    Digitale Medien
    Digitale Medien
    Preparative fractionation of lignin by gel-permeation chromatography (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 135-153 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The combination of an agarose gel (Bio-Gel A) and a dioxane-water (1:1) solvent system allowed the fractionation, on a preparative scale, of a very polydisperse, non-derivatized lignin preparation (enzymatically liberated lignin prepared from sweetgum sapwood with Lenzites trabea). Three fractions differing markedly in molecular weight were obtained. A gel of crosslinked alkylated dextran (Sephadex LH-20) with the same solvent system allowed division of the lowest molecular weight fraction into two fractions. These materials were characterized by measurements of intrinsic viscosity and number-average molecular weights in dimethylformamide and dioxane-water. It was established that the two highest molecular weight fractions were associated in an average trimeric form in dioxane-water (1:1) as compared to the form (considered to be molecular) that occurred in dimethylformamide. Molecular size distributions and eluant volumes of the fractions were determined with a Sephadex G-100-formamide system, the latter being one of the most powerful nonaqueous solvents for lignin. Adsorption effects were known to be absent in this case, and the lignin molecules were considered to be unassociated in formamide. The four fractions were distinguishable with the formamide-G-100 system, thus indicating that the original fractionation was based on molecular size. The enzymatically liberated lignin contained molecules that comprised a continuum of molecular weights from approximately monomeric to molecules that were at the limit of the solvating power of dioxane-water (1:1) and dimethylformamide. Limited physicochemical data were consistent with a compact, approximately spherically symmetric shape of the lignin in solution.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070202
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  • 71
    Digitale Medien
    Digitale Medien
    Intrachain potential energy of the α-helix and of a coiled coil strand (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 189-197 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A comparison has been made of the intrachain potential energy of an infinite straight α-helix of poly-L-alanine with that of the distorted form adopted in a coiled coil conformation. The energy terms included were the van der Waal's, electrostatic, hydrogen-bond, and the rotational potential terms. The results indicate that the potential energies of the structures investigated are almost the same, and so a transformation from one state to another may occur without significant changes in potential energy. Particular care has been taken to ensure that the electrostatic and van der Waal's interaction terms are fully convergent. The values obtained for the α-helix were compared with those already published, and some significant differences were found.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070205
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  • 72
    Digitale Medien
    Digitale Medien
    Optical rotatory dispersion of mucopolysaccharides and mucopolysaccharide-dye complexes. II. Ultraviolet cotton effects in the amide transition bands (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 173-187 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ultraviolet optical rotatory dispersion curves of mucopolysaccharides exhibit particular Cotton effects in the spectral region of the n-π and π-π amide transitions. Two general patterns emerge: (1) enhancement of negative rotation and of the first negative Cotton effect (troughs 217-220 mμ) and (2) relative dominance of the positive Cotton effect in the π-π transition region (peak ∼198 mμ). Groups (1) and (2) can be correlated with a structural difference in the linkages of the amino sugars: (1) occurs with polymers containing 3-1-linked glycosamino sugars and (2) with glycosamino moieties linked 4-1 by either α- or β-glycosidie bonds. Measurements of the circular dichroic absorption bands support the qualitative conclusions from optical rotation. All mucopolysaccharides exhibit a first, negative band centered at 208-211 mμ, while only those in group (2) show, in addition, a positive band centered at 189-192 mμ. A suggested unifying model considers that difference in kind and/or degree of preferred geometry of the amide groups obtains from two forms of secondary order: (1) having a linear hydrogen bond from the N (acceptor) to the (C2)O - H of the preceding uronic acid and (2) having a linear hydrogen bond from the N (acceptor) to the (C2 or 3) O - H of the following sugar. The hydrogen bonds would have similar strength but opposite directions in two systems towards the nonreducing end (1) or towards the reducing end (2)], closing eight-membered rings
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070204
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  • 73
    Digitale Medien
    Digitale Medien
    Studies on the myosin molecule from smooth muscle (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 99-106 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The myosin molecule was extracted from the smooth muscle parts of horse esophagus and purified by ammonium sulfate fractionation. The schlieren pattern of the sedimentation velocity run showed a very sharp single peak of.5.9. S (s20,w). Molecular weight of the protein was measured by means of the Archibald and sedimentation equilibrium methods, both in 0.5M KCI buffered by 1/150 M phosphate at pH 7.5 and at 5°C. The values obtained were 6.25 × 105 and 5.81 × 105respectively, for the two methods. The second virial coefficients were 1.1 × 104 and 1.2 × 10-4 ml/g. Denatured smooth muscle myosin was prepared in a solution of 5M guanidine HC1 containing 0.4 M KC1 and 0.2 M β-mercaptoet hanol buffered at pH 8.0. The weight-average molecular weight of the denatured smooth muscle myosin was 2.24 × 105 and the second virial coefficient was 7.6 × 10-4 ml/g. The values described above are in good agreement with those reported for rabbit skeletal myosin with ammonium sulfate fractionation. The molecular dimension of the molecule is estimated as the value for an axial ratio of 100, assuming a rigid rod molecular model for this molecule, both the thermodynamical and hydrodynamical treatment being in a good agreement with this estimation.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070110
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  • 74
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070401
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  • 75
    Digitale Medien
    Digitale Medien
    Conformation of polypeptide in the, helix-coil transition region (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 433-434 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: No. Abstract
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070314
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  • 76
    Digitale Medien
    Digitale Medien
    Experimental thermodynamics of the helix-random coil transition. II. Calorimetric measurement of transition enthalpies of poly A in acid aqueous solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 423-431 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The enthalpy change accompanying the double helix-coil transition of polyriboadenylic acid (poly A) in aqueous solution has been measured optically and calorimetrically in the pH range 5.7-4.5. The course of this cooperative transition was followed optically by measuring changes in ultraviolet absorption as a function of temperature at different pH values, and calorimetrically by determining the heat capacity of the solution through the transition region. From the latter measurements, the enthalpy of transition was calculated. It is shown, that ΔH is dependent on pH as it is expected from the influence of protonation of the double helix of poly A.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070313
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  • 77
    Digitale Medien
    Digitale Medien
    Mechanical properties of poly(glutamic acid) in aqueous solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 453-458 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The interaction between ionizable carboxyl groups and the conformation of poly-(glutamic acid) (PGA) in aqueous solution were investigated by the mechanical method. The dynamic rigidity of the PGA solution has a maximum value at the pH corresponding to about 50% neutralization point. This may be due to establishing of a maximum attractive force by proton/charge fluctuation between ionizable carboxyl groups at that pH. The dynamic viscosity has a sharp change in the region of pH 5.5-6.5. It is suggested that this behavior is due to the helix-coil transition.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070404
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  • 78
    Digitale Medien
    Digitale Medien
    Proton relaxation in aqueous DNA solutions (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 447-452 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By use of D2O we found that the shortening of the longitudinal proton relaxation time which occurs in the investigated aqueous yeast DNA solutions (≦ 2.4% with 2% protein) was not based on a hydration effect, but was caused by magnetic impurities only. An estimate shows that the mobility of the hydrated water molecules is reduced by less than two orders of magnitude in comparison with the free water molecules.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070403
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  • 79
    Digitale Medien
    Digitale Medien
    Method of determining the relative stability of different conformational states of biological macromolecules (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 435-445 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A general approach to the determination of relative stability of any pair of con-formational states of biological macromolecules or their complexes (in particular, to the determination of relative stability of native and disordered states of the macromolecule) has been suggested. For determining the free energy difference of the two states under the conditions when one of them is considerably more advantageous than the other, it is necessary for the macromolecule to be influenced by the transforming agent which levels free energies of both the conformational states, and to determine the external parameter derivative of the free energy difference in the region of the conformational transition induced by the change in this parameter. If the character of the dependence of this derivative on the external parameter (temperature, solvent composition, etc.) is known, then this allows the determination of the free energy difference of the two states under the conditions considered, even including conditions far from the transition region. The value of the derivative of the free energy difference in the transition region in many cases can be measured directly (in particular, when using calorimetry), while in cases when a direct measurement of the derivative is impossible, it can often he estimated experimentally from the steepness of the conformational transition. The methods of this estimation and also a possible character of the change of the considered derivative during variation of the external parameter are considered for the case when the transforming agent is one of the components of the solvent and, consequently, the derivative of the free energy difference is equal to the difference of number of molecules of this component hound with the macromolecule in two conformational states.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070402
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  • 80
    Digitale Medien
    Digitale Medien
    Heats of fusion of various amounts of absorbed water in wool keratin (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 459-474 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Wool-water systems, at water contents above a threshold value of 22.7 g of water per 100 g of wool keratin, yielded curves of specific heat against temperature showing peaks that are ascribed to the fusion of the absorbed water. Integral and incremental heats of fusion were obtained. Integral heats increase as the square of the water content above the threshold, and incremental heats follow a linear relationship. The incremental heat reaches a value of 55 cal/absorbed water, at the saturation water content, at 0°C of 33.9 g of water per 100 g of keratin. The state of the absorbed water is discussed. Clustering of water molecules takes place only above the threshold water content.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070405
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  • 81
    Digitale Medien
    Digitale Medien
    Raman spectroscopy of poly-L-proline in aqueous solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 173-179 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The laser-excited Raman spectra have been obtained of poly-L-proline in the solid and aqueous solution. In the solid state, the Raman spectra are of the form II which is the left-handed helical form with the peptide bonds in the trans configuration. Dissolution of this form in water produced only minor changes in the Raman spectra. The differences in frequencies produced by dissolving the polymer are associated with vibrational modes of the pyrrolidine ring as indicated by comparison with the Raman spectrum of L-proline. The similarity of the Raman spectra dictates that, the conformations of poly-L-proline chain are similar in the solid and aqueous solution.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080204
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  • 82
    Digitale Medien
    Digitale Medien
    Mise en évidence d'une relation entre la longueur el la constante de sédimentation des molécules de DNA en solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 181-185 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A comparative study on sonicated calf thymus DNA was made by using electron microscopy and sedimentation methods. The length distribution, established by electron microscopy by using Kleinschmidt's technique, is related to the sedimentation curve obtained with the same solution. The relation permits a determination of the sedimentation constant corresponding to a given length up to 8000 Å and vice versa.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080205
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  • 83
    Digitale Medien
    Digitale Medien
    Optical anisotropy of synthetic polynucleotides. II. Calculation of π-electron polarizability of uracil and adenine (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 199-216 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The π-electron polarizability of conjugated base molecules such as uracil and adenine are calculated semiempirically by using molecular orbital theories. The Hüekel method and the self-consistent-field (SCF) theory are used in the present calculation. The theoretical values obtained by the Hüekel method are consistently larger than the experimental results. The values obtained by the SCF theory are in good agreement with observed values. It is clearly demonstrated that the SCF method is better than the Hükel method for the calculation of polarizability. The polarizability of the adenine-uracil pair is calculated as the sum of the polarizabilities of adenine and uracil and also calculated by solving the eigenvalue problem for the A-U pair as an entity. The second method gives considerably larger polarizability than the first method. Discussions are presented and it is demonstrated that the second method is the correct way to calculate the polarizability of the A-U pair.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080207
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  • 84
    Digitale Medien
    Digitale Medien
    Reversibility of thermal transitions in proteins: Racemization and aggregation as factors in the reversible denaturation of a soluble keratin derivative (SCMKA) (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 187-198 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reversibility of the thermal denaturation of a low-sulfur fraction of solubilized wool keratin (SCMKA) has been studied under a variety of conditions of time, protein concentration, and pH. Two types of irreversibility for the transition have been encountered. One of these is associated with an aggregation of the protein on denaturation to give a product which may contain elements of a β conformation. This type of irreversibility is favored by high protein concentration, and the original conformation may in fact be regained if the aggregated structure is broken down by a solvent such as 8M urea and the urea subsequently removed by dialysis. The other type of irreversibility appears to be due to racemization of the protein. It does not seem to be dependent on protein concentration and is apparent only at temperatures beyond the actual transition range (∼40-65°C) at pH values below 11, At pH 12, however, racemization appears to proceed slowly even at 4°C. The thermal transition at pH 9 and pH 10 has been shown to be multistage in nature. Over the pH range 9-12 there is a progressive decrease in thermal stability with increase of pH. Addition of NaCl at pH 10 leads to an increase in thermal stability of the molecule.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080206
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  • 85
    Digitale Medien
    Digitale Medien
    Studies of the optical properties of the proflavine-DNA complex (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 217-235 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: We report studies of the optical properties of the proflavine-DNA complex, using absorbance and circular dichroism spectroscopy. From comparison of the absorption spectra of proflavine complexed with calf thymus and T2 DNA, we conclude that stacking of the dyes external to the double helix is comparatively much weaker with T2 DXA, probably because of its glucosylation. Several sources are found for the circular dichroism induced in proflavine when it is complexed with DNA. There is a relatively weak circular dichroism induced when the dye is infinitely dilute on the DNA lattice; this presumably arises from the environmental asymmetry of the binding site. Stronger circular dichroism effects are induced by interaction of intercalated and stacked dyes; studies with T2 DNA, for which stacking seems to be blocked, permit a tentative resolution of effects due to the two modes of binding. One recurring theme of these studies is the observation that the optical properties are quite dependent on environment. The most dramatic example is a strong variation with salt concentration of the amplitude of the circular dichroism induced in the isolated (intercalated) monomer by the surrounding DNA. This suggests that the structure of the intercalated complex is quite sensitive to external conditions.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080208
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  • 86
    Digitale Medien
    Digitale Medien
    Binding of alcohols to the peptide CO-group of poly-L-proline in the I and II conformation. I. Demonstration of the binding by infrared spectroscopy and optical rotatory dispersion (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 237-246 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The binding of n-butanol, benzyl alcohol, and trifluoroethanol to polyproline I (all peptide bonds in cis configuration) and II (all peptide bonds in trans configuration) has been demonstrated. It was found by infrared spectroscopy that hydrogen bonds are formed between the CO groups of the polymer and the OH groups of the alcohols. Their strength increases from n-butanol via benzyl alcohol to trifluoroethanol. The binding of benzyl alcohol could also be followed by optical rotatory dispersion due to the fact that the electronic transitions of the benzyl ring are rendered optically active by the binding to the polymer.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080209
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  • 87
    Digitale Medien
    Digitale Medien
    Helix-random coil phase transitions in polypeptide systems with random defects: A statistical mechanical model (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 259-274 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The statistical mechanics of the effect of a small number of randomly occurring defects on the melting of a polypeptide chain is developed by using a perturbation of Boltzmann factors technique. The method is illustrated by an example where a second-component impurity contributes more to the energy of the hydrogen-bonded superstructure of the polypeptide chain than does the dominant amino acid residue, resulting in the overall destabilization of the helical conformation.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080211
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  • 88
    Digitale Medien
    Digitale Medien
    Deformation behavior of erythrocyte ghost (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 275-287 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Biological membranes consist mainly of lipids and proteins. At present, the structure of the lipid phase appears to be established, but hypotheses on the molecular organization of the protein are difficult to support. Thus the deformation behavior of whole human erythrocyte ghosts, ghosts after the selective removal of lipids and ghosts stripped of lipids as well as nonlipid components have been examined in the hope of securing indirect information on the organization of the protein. It has been found that large localized deformations result in partial membrane failure and long uniformly wide fibrils, frequently in excess of 3000 Å, are drawn across the rupture. These data are interpreted in terms of currently favored membrane models and the possibility of a fibrous membrane framework consisting predominantly of protein is reviewed. The behavior of the membrane in its various stages of extraction is compared and contrasted to that of synthetic polymer films of known organization.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080212
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  • 89
    Digitale Medien
    Digitale Medien
    Helix-coil transition of poly-N5-(3-hydroxypropyl)-L-glutamine: Thermodynamic and statistical analysis (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 247-257 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The thermally induced conformational changes of poly-N5-(3-hydroxypropyl)-L-glutamine in water and in methanol-water (3:7 v/v) have been analyzed in terms of the Lifson-Roig theory. The transitions in both solvents can be described by using v = 0.017. The thermodynamic parameters for the random coil-to-helix transition of one amino acid residue at room temperature were found to be: in water, ΔH = - 130 cal/mole and ΔS = - 0.45 e.u.; in methanol-water (3:7 v/v), ΔH = - 170 cal mole and ΔS = - 0.45 e.u. The size distribution of helical segments is broad, and the results of numerical calculations are presented for three degrees of polymerization (DP = 100, 300, and 750).
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080210
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  • 90
    Digitale Medien
    Digitale Medien
    Extrinsic cotton effects of 9-aminoacridine bound to deoxyribonucleic acid and poly(α, L-glutamic acid) (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 289-292 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080213
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  • 91
    Digitale Medien
    Digitale Medien
    Molecular weight and dimensions of phycocyanin monomer and aggregates (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 293-295 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080214
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  • 92
    Digitale Medien
    Digitale Medien
    Molecular weight and shape of phycocyanin monomer and aggregates (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 297-299 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080215
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  • 93
    Digitale Medien
    Digitale Medien
    Equilibrium sedimentation of a polyelectrolyte in a density gradient of a low-molecular weight electrolyte. I. DNA in CsCl (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 303-304 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080217
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  • 94
    Digitale Medien
    Digitale Medien
    Cesium chloride density distributions in preparative equilibrium ultracentrifugation and computer program (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 301-301 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080216
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  • 95
    Digitale Medien
    Digitale Medien
    Nmr studies in solution of poly-L-proline (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 304-304 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080218
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  • 96
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360080301
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  • 97
    Digitale Medien
    Digitale Medien
    Optical activity of simple cyclic amides in solution (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 595-610 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The cyclic dipeptide, L-alanylglycyl anhydride, has been studied by optical rotatory dispersion; both L-alanylglycyl anhydride and the lactam, L-3-aminopyrrolidin-2-one, have been studied by circular dichroism. In hydroxylic solvents the circular dichroism spectra of 3-aminopyrrolidin-2-one can be attributed to an n-π* transition near 220 mμ and a π-π* transition near 190 mμ. In these solvents the optical activity of L-alanylglycyl anhydride can be explained as being due to contributions of n-π* transitions and a split π-π* transition. In acetonitrile, however, the circular dichroism spectrum of 3-aminopyrrolidin-2-one shows an additional apparent minimum near 200 mμ. The CD spectrum of the dipeptide is also quite distinctive in this solvent. The possible nature of the band at 200 mμ and the implications of these findings are discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070415
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  • 98
    Digitale Medien
    Digitale Medien
    Interaction between DNA and the polybases polyarginine and polylysine in equivalent precipitates (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 619-623 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070418
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  • 99
    Digitale Medien
    Digitale Medien
    Masthead (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969) 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070501
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  • 100
    Digitale Medien
    Digitale Medien
    Backbone conformation of amino acidsContribution No. 260 from the Centre of Advanced Study in Biophysics, University of Madras, Madras-25, India. (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 624-626 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1969.360070419
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