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  • 1975-1979  (913)
  • 1965-1969
  • 1935-1939
  • 1977  (913)
  • Inorganic Chemistry  (816)
  • Bone
  • Rat
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Materialart
Erscheinungszeitraum
  • 1975-1979  (913)
  • 1965-1969
  • 1935-1939
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Das Anastomosengeschwür am operierten Magen (1977)
    Springer
    Langenbeck's archives of surgery 343 (1977), S. 133-151 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Peptic ulcer ; Anastomosis ; Duodenogastric reflux ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die vorliegende Studie gilt dem Anastomosengeschwür am operierten Magen. Diese schwerwiegende Komplikation entsteht nahezu ausschließlich nach Resektionsverfahren mit duodenaler Exklusion (Billroth II; Verlegung des Duodenum in den Nebenschluß). - An 54 männlichen Wistarratten wurden verschiedene Formen der duodenalen Exklusion mit und ohne duodenogastrischen Reflux durchgeführt. Die Ergebnisse unserer Untersuchungen zeigen, daß nach duodenaler Exklusionmit Reflux gesetzmäßig peptische Anastomosengeschwüre entstehen. Der kontinuierliche Reflux von Galle und Pankreassekret ist der ausschlaggebende ätiologische Faktor für die Ulcusentstehung im Grenzgebiet der Anastomose von Magen und Dünndarm. Stase im ausgeschalteten Zwölffingerdarm (Syndrom der zuführenden Schlinge) fördert die lcerogene Refluxwirkung. Fehlt der Pylorus, so potenzieren sich Reflux und Stase zur größten Ulcusfrequenz (〉 90%). Bei erhaltenem Pylorus ist die Geschwürsincidenz wesentlich geringer. Der duodenogastrische Reflux hemmt die meßbare Salzsäuresekretion signifikant (P 〈 0,01); Salzsäure spielt demnach für die Entstehung des experimentellen Anastomosengeschwürs der Ratte keine wesentliche Rolle. - Im Hinblick auf die Prophylaxe des Anastomosengeschwürs führen diese Erkenntnisse zu der Forderung, auf Operationsverfahren mit duodenaler Exklusion und Reflux (Billroth II) zu verzichten und das Operationsziel bei der Magenresektion auf die Wiederherstellung der orthograden MagenDarm-Passage zu richten.
    Notizen: Summary Different types of duodenal by-pass operations with and without duodenogastric reflux were performed on 54 male Wistar rats. The results of our investigation show that following duodenal by-pass with reflux peptic anastomotic ulcer regularly occurs. The constant reflux of bile and pancreas juice is the most important aetiologic factor in the development of ulcer in the vicinity of the anastomosis between the stomach and small intestine. Stasis in the by-passed duodenum (afferent loop syndrome) promotes ulcerogenic action of reflux. In the absence of the pylorus the effects of ref lux and stasis potentiate, resulting in a high frequency of ulcer (〉 90 %). With intact pylorus the incidence is low. Duodenogastric reflux prevents hydrochloric acid secretion significantly (P 〈 0.01); hydrochloric acid thus plays a minor role in the development of experimental anastomotic ulcer of the rat. - In considering the prophylaxis against anastomotic ulcer, these findings support the claim of avoiding surgical techniques involving duodenal by-pass and reflux (Billroth II with short loop GE). Gastric resection should, therefore, aim at the reconstruction of the orthograde peristalsis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01262005
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  • 2
    Digitale Medien
    Digitale Medien
    Microridge cells in the larynx of the male white rat. Investigations by reflection scanning electron microscopy (1977)
    Springer
    European archives of oto-rhino-laryngology and head & neck 215 (1977), S. 1-9 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Respiratory epithelium ; Larynx ; Microridge cells ; Rat ; Scanning electron microscopy ; Respiratorisches Epithel ; Kehlkopf ; Mikroleistenzelle ; Ratte ; Rasterelektronenmikroskopie
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Kehlkopfepithel ausgewachsener männlicher Albinoratten wird rasterelektronenmikroskopisch untersucht. Zusätzlich zu den zilientragenden und zu den Mikrovillizellen, zu den Bürsten- und Becherzellen, welche insgesamt für das respiratorische Epithel charakteristisch sind, werden in bestimmten Abschnitten des Larynx die Mikroleisten- oder Labyrinthzellen beschrieben. Die freie Oberfläche typischer Labyrinthzellen ist durch ein System von sich verzweigenden Mikroleisten gekennzeichnet, die miteinander durch Querbrücken verbunden sind und in der Zellperipherie eine bevorzugte Parallelausrichtung zur Zellgrenze zeigen können. Der Durchmesser der Mikroleisten beträgt ca. 0,05–0,15 μm. Die Querverbindungen zwischen den Mikroleisten haben einen Durchmesser von ca. 0,01 μm. Der Raum zwischen zwei benachbarten Querbrücken variiert. Labyrinthzellen können außer Mikroleisten auch Mikrovilli zeigen und es gibt Übergänge zwischen den Mikroridge- und den Mikrovillizellen. Die bevorzugte Lokalisation der Mikroleistenzellen im Bereich der Glottis und des Aditus laryngis wird belegt. Die mögliche Funktion dieser Zellen und ihre Bedeutung für die Diagnostik pathologischer Schleimhautveränderungen wird diskutiert.
    Notizen: Summary The laryngeal epithelium of male white rats is studied by reflection scanning electron microscopy (SEM). In addition to ciliated cells, microvilli cells, brush cells and goblet cells that are characteristic for normal respiratory epithelium the microridge or labyrinth cell can be seen in particular regions of the larynx. The apical surface of a typical labyrinth cell is characterized by a system of narrow standing microridges of about 0.05–0.15 μm in diameter and interconnecting microridges with a diameter of about 0.01 μm. The microridge system of a labyrinth cell originates from the fusion of densely standing microvilli. Between microridge cells and microvilli cells all transition forms can be observed. The preferable localiziation of the microridge cell in the larynx and its possible function is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00463186
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  • 3
    Digitale Medien
    Digitale Medien
    Rasterelektronenmikroskopische Studien zur Feinstruktur des Epiglottisepithels von Ratten (1977)
    Springer
    European archives of oto-rhino-laryngology and head & neck 217 (1977), S. 41-51 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Respiratory epithelium ; Epiglottis ; Rat ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The epithelial surface of the epiglottis in adult male and female albino rats is studied by scanning electron microscopy. Prominent differences exist between the surface morphology as observed in the males and that observed in the females sacrificed in the estrus phase of the ovarial cycle. The differences are most pronounced in respect to the amount of secretory vesicles, microvilli- and microridge-cells and in respect to the observable number of desquamating cells. The existence and the importance of the microridge-cells are discussed. Special attention is also paid to the results indicating that at least some parts of the extrapulmonary airway epithelia act as possible target organs for sex hormones. Finally the importance of the observed differences is discussed for the correct interpretation of pathomorphological alterations in the extrapulmonary airway epithelia that have been observed under experimental conditions and during infections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00453889
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  • 4
    Digitale Medien
    Digitale Medien
    Cyclic nucleotide phosphodiesterases of human and rat gastric mucosa (1977)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 296 (1977), S. 187-190 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Cyclic nucleotide phosphodiesterase ; Gastric mucosa ; Human ; Rat ; Inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cyclic adenosine-3′,5′-monophosphate (cAMP) phosphodiesterases (PDE) were partially purified from human and rat gastric mucosa. Drugs known to affect the cyclic nucleotide system and/or gastric secretion were tested for effects on the PDE-activities from both species. In rat gastric mucosa PDE-activity can be detected in the 100 000×g sediment (K m =8.3 μM; V max=3.2 nmoles cAMP hydrolyzed/mg protein x min) and the cytoplasma (K m =5.6 μM; V max=2.6 nmoles cAMP hydrolyzed/mg protein x min). The most effective inhibitors of the particle-bound activity are papaverine (K i =4 μM, non-competitive) and 3-isobutyl-1-methylxanthine (K i=14 μM, competitive). There was only a modest competitive inhibition by theophylline (K i =495 μM). PDE-activity in the cytoplasma was inhibited competitively by these three drugs (papaverine: K i =6.5 μM; 3-isobutyl-1-methylxanthine: K i =37 μM; theophylline: K i =152 μM. In human gastric mucosa PDE-activity can be detected in the particular fraction (K m =23.9 μM; V max=1.2 nmoles cAMP hydrolyzed/mg protein x min), and the soluble fraction (K m =12.1 μM; V max=2.4 nmoles cAMP hydrolyzed/mg protein x min). PDE-activity in the 100 000×g sediment was inhibited by papaverine (K i =5.6 μM, non-competitive), 3-isobutyl-1-methylxanthine (K i =16 μM, non-competitive), theophylline (K i =165 μM, non-competitive), and N6-2′-O-dibutyryl-cAMP (K i =746 μM, competitive). Inhibition in the 100 000×g supernatant was noncompetitive with 3-isobutyl-1-methylxanthine (K i =7.1 μM and papaverine (K i =8.5 μM), but competitive with N6-2′-O-dibutyryl-cAMP (K i =170 μM), and theophylline (K i =225 μM). This study indicates that PDE-activities of the two species are qualitatively similar, but quantitative differences exist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00508473
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  • 5
    Digitale Medien
    Digitale Medien
    Isolation of osteoclasts by velocity sedimentation at unit gravity (1977)
    Springer
    Calcified tissue international 22 (1977), S. 303-313 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Osteoclasts ; Sedimentation ; Isolation ; Cells ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract A method is presented for separating osteoclasts from the heterogeneous population of bone and marrow cells. Cell suspensions were prepared from femora of young rabbits by mechanical dispersion. The starting cell suspension typically contained only 1.0%±0.5 osteoclasts. Following an initial 45 min of unit gravity sedimentation in a lucite chamber osteoclasts were primarily distributed in fractions 2–5. A second 45-min sedimentation of these pooled fractions yielded cell suspensions containing greater than 30% osteoclasts (as much as a 50-fold increase over starting percentages). Linear scan analysis, however, revealed that osteoclasts accounted for 73.14%±0.58 of the cell colume. Subsequent in vitro experiments demonstrated linear incorporation of3H-leucine into TCA precipitable protein for cells comprising the osteoclast fraction. Concomitant radiautographs revealed radioactive label in isolated osteoclasts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010369
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  • 6
    Digitale Medien
    Digitale Medien
    The comparative effects of dichloromethylene diphosphonate (Cl2MDP) and ethane-1-hydroxy-1,1-diphosphonate (EHDP) on growth and modeling of the rat tibia (1977)
    Springer
    Calcified tissue international 23 (1977), S. 207-214 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Diphosphonates ; Bone resorption ; Bone formation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Male rats weighing 100 g were assigned to groups and injected daily for 10 days with vehicle (control), 0.4, 2.0, 4.0, 10.0, or 20.0 mg/kg/day of ethane-1-hydroxy-1,1-diphosphonate (EHDP) or dichloromethylene diphosphonate (Cl2MDP). The proximal tibial metaphysis and epiphysis were assayed for changes in percentage of hard tissue and bone formation parameters. From the data, information about hard tissue resorption was deduced. All doses of Cl2MDP and doses of 2.0 mg EHDP/kg/day and greater caused significant increases in percentage of hard tissues with Cl2MDP being more effective than similar doses of EHDP in decreasing bone resorption. Osteoclast population parameters were increased with all doses of both Cl2MDP and EHDP with Cl2MDP having a greater effect than similar doses of EHDP. Decreases in the proliferation of the osteoprogenitor pool parallel the decreases in osteoblasts and bone formation parameters. These decreases in osteoprogenitor pool proliferation do not account for the increases with diphosphonates in osteoclast population parameters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012787
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  • 7
    Digitale Medien
    Digitale Medien
    Quantitative analyses of osteoclast changes in resorbing bone organ cultures (1977)
    Springer
    Calcified tissue international 23 (1977), S. 283-289 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Resorption ; Osteoclast ; Quantitation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The stimulation of bone resorption, assessed by the release of45Ca from prelabeled bones, was associated with an increase in number of osteoclasts per bone section in parathyroid hormone (PTH)-treated bones, but not in lipopolysaccharide (LPS)-treated bones. By contrast the number of nuclei per osteoclast increased following LPS treatment, but was not affected by PTH. LPS-treated bones had more multinucleated cells, some having as many as 27 nuclei per osteoclast. More osteoclasts were adjacent to the bone collar in bones treated with LPS or PTH than in control bones. In LPS-treated bones this area also contained the largest osteoclasts, as determined by the greatest number of nuclei per osteoclast. The results suggest that LPS and PTH stimulate osteoclastic resorption by different mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012798
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  • 8
    Digitale Medien
    Digitale Medien
    Preliminary studies on the binding of plasma albumin to bone tissue (1977)
    Springer
    Calcified tissue international 23 (1977), S. 303-305 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Albumin ; Bone ; Hydroxyapatite ; Plasma protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The extractability of125I-labelled plasma albumin from bone pieces and from powdered bone has been compared after both in vivo and in vitro incorporation. The results show that albumin is more readily extracted from bone pieces than from bone powder which implies that tissue disruption exposes additional protein adsorption sites. It is suggested that incorporation of plasma albumin into calcified matrix during bone formation occurs mainly as a result of its strong interaction with bone mineral.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012801
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  • 9
    Digitale Medien
    Digitale Medien
    Cortical bone remodeling in normal rat (1977)
    Springer
    Calcified tissue international 23 (1977), S. 161-170 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Growth ; Rat ; Remodeling ; Tetracyclines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Cortical bone remodeling along the femur diaphysis was determined in normal female rats (Sprague-Dawley) with the tetracycline technique. Three segments on the cortical bone circumference (the anterolateral, the medial, and the posterior) were found to be most suitable for the study of the remodeling process. Oxytetracycline was administered at age 60 and 75 days, and groups of animals were killed at age 75, 85, 95, and 105 days. The accumulated endosteal growth during age 60 to 75 days in the anterolateral segment was found to increase uniformly in the distal direction along the femur diaphysis. A method is described where this accumulated endosteal growth is used. This method eliminates the use of calipers to determine the section level and makes it possible to study comparable sections even after varying periods of time. The proximal part of the diaphysis showed periosteal apposition in all three segments. The periosteal apposition turned into resorption in the distal part of the diaphysis in the anterolateral and medial segments, whereas the periosteal appsition increased in the posterior segment. The endosteal growth increased in the distal direction in the anterolateral and medial segments. Irregular OTC bands made measurements of endosteal remodeling in the posterior segment impossible. The cortical width decreased in the distal direction along the femoral shaft. Comparison between the different age groups is described and also the relation between the accumulated endosteal growth and the diameter of the medullary cavity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012782
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  • 10
    Digitale Medien
    Digitale Medien
    Bone water (1977)
    Springer
    Calcified tissue international 23 (1977), S. 1-5 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Water ; Bone ; Homeostasis ; Structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary A short review is given of the water in bone. Various analyses of bone water content are discussed, and its possible location is considered in relation to the behaviour of water in isolated components of bone. Some of the difficulties encountered in examining such microscopic phenomena as water structure in a heterogeneous system such as bone are also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012759
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  • 11
    Digitale Medien
    Digitale Medien
    Mechanism of induction of hypercalcemia and hyperphosphatemia by lead acetate in the rat (1977)
    Springer
    Calcified tissue international 24 (1977), S. 41-46 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Lead salt ; Bone ; Mobilization ; Hypercalcemia ; Hyperphosphatemia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The present study is an investigation of the mechanism of hypercalcemia and hyperphosphatemia induced by the intravenous injection of lead acetate (Pb-Ac). A total of 118 male rats were injected with 30 mg/kg of Pb-Ac, or with 16.5 mg/kg of sodium acetate as the control. The levels of serum calcium, phosphorus and lead were then determined at various time periods after the injections. Serum calcium and phosphorus levels increased with time after Pb-Ac injection and the maximum values of calcium (17 mg%) were found after 1 h and of phosphorus (13.5 mg%) after 30 min. Both calcium and phosphorus levels reverted to the normal range after 12 h. The maximum net rates of increase of calcium and phosphorus were found immediately after Pb-Ac injection. At that time, deposition of lead at the calcifying sites of bone and incisor dentin was demonstrated by a histochemical examination. In other experiments the changes in the calcium and phosphorus contents in the medium after shaking bone powder in serum with Pb-Ac in an in vitro system were studied. It was confirmed that the calcium and phosphorus were displaced from the bone mineral, the extent of the displacement being correlated with the concentration of the Pb-Ac added to the medium, and that these displacements were very rapid reactions. These results suggest that hypercalcemia and hyperphosphatemia following Pb-Ac injection results from a direct action of lead on the bone mineral.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223295
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  • 12
    Digitale Medien
    Digitale Medien
    Effect of endogenous and infused parathyroid hormone on plasma concentrations of recently administered45Ca (1977)
    Springer
    Calcified tissue international 24 (1977), S. 209-214 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Parathyroid hormone ; Plasma calcium ; Radiocalcium ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The net rate of loss of45Ca from plasma was monitored in normal, thyroparathyroidectomized (TPTX), and nephrectomized rats. Also studied was the effect of a 24 h intravenous infusion of PTH in TPTX rats. The45Ca was injected after an overnight fast and 1 to 4 h prior to the time the first blood sample was obtained. In normal rats, the net rate of loss of45Ca from plasma was slower than in TPTX rats for at least 12 h after radionuclide injection. Nephrectomy did not affect this difference between control and TPTX rats until 8 h after45Ca injection or about 18 h after nephrectomy. At this time a reversal occurred and the net rate of plasma45Ca loss in nephrectomized rats with parathyroids became faster than in TPTX nephrectomized rats. When PTH was infused at a constant rate (3 mU/g body weight/h) plasma calcium concentrations rose gradually for approximately 12 h after which a constant plasma calcium level was maintained with continued PTH infusion. During the period when plasma calcium concentrations were rising, the net rate of loss of45Ca from plasma was slower than in TPTX controls infused only with saline. However, when plasma levels stabilized, plasma45Ca disappearance rates changed such that the rate loss of45Ca from plasma became faster in PTH-infused than in TPTX controls. It is concluded that PTH increases calcium efflux from the same compartment in bone which receives calcium from plasma, thereby returning some recently deposited45Ca to plasma. In the non-equilibrated state, this returns additional45Ca to plasma causing anet decrease in the rate of loss of45Ca from plasma. However, in the equilibrated condition, when both calcium efflux from bone and influx into bone are in balance but at higher flux rates, PTH stimulates the diffusion of45Ca into other bone compartments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223318
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  • 13
    Digitale Medien
    Digitale Medien
    An analysis of response properties of spinal cord dorsal horn neurones to nonnoxious and noxious stimuli in the spinal rat (1977)
    Springer
    Experimental brain research 27 (1977), S. 15-33 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Spinal cord ; Dorsal horn interneurones ; Pain mechanisms ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electrophysiological properties of neurones in the spinal cord dorsal horn were studied in decerebrated, immobilized spinal rats. Extracellular recordings were performed at the thoraco-lumbar junction level. Each track was systematically located by extracellular injection of pontamine sky blue. According to their responses to mechanical peripheral stimuli, cells were classified in four classes: Class 1 cells: Cells activated only by nonnoxious stimuli. They were divided into — 1A: hair movement and/or touch and 1B: hair movement and/or touch and pressure or pressure only. Class 2 cells: Cells driven by both nonnoxious and noxious stimuli, divided into — 2A: hair movement and/or touch, pressure, pinch and/or pin-prick, and 2B: pressure, pinch and/or pin-prick. Class 3 cells: Cells only activated by noxious stimuli (pinch and/or pin-prick). Class 4 cells: Cells responding to joint movement or pressure on deep tissues. Peripheral transcutaneous or sural nerve stimulation clearly showed that class 1 cells were activated only by A fiber input while 68% of classes 2 and 3 cells received A and C input. Histological examination indicated that cells driven only by noxious input were located either in the deepest part or in the marginal zone (lamina I) of the dorsal horn. Nevertheless, some lamina I cells were also driven by both nonnoxious and noxious stimuli. In addition, there is a great deal of overlap between class 1 and class 2 cells. This fact was confirmed by considering the wide distribution in the dorsal horn of cells receiving A and C input. However, spinal organization of the different classes of cells consists of a preferential distribution rather than a strict lamination. This study indicates that properties of dorsal horn interneurones in the rat have a high degree of similarity with those previously described in other species (cat and monkey).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234822
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  • 14
    Digitale Medien
    Digitale Medien
    The influence of the amygdala on the basal septum and preoptic area of the rat (1977)
    Springer
    Experimental brain research 29 (1977), S. 249-263 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Preoptic area ; Basal septum ; Amygdala ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Extracellular microelectrode recordings were made from single neurones in the medial preoptic area and basal septum of normal female rats anaesthetised with urethane and the effects of stimulation of the ipsilateral amygdala (AMY) was tested. 1. Quiescent cells were excited with latencies between 4 and 〉 40 msec with the majority being between 10 and 27 msec. Variable latency, changing latency and recruitment were observed and suggest that many pathways are oligo- or polysynaptic. 2. A minority of spontaneously active units (20.6%) were excited with latencies between 5 and 36 msec. The predominant initial response was inhibition (67.1%). The remaining 12.3% of neurones did not respond. 3. A predominantly positive complex field potential was associated with excitation, particularly of quiescent neurones. 4. Inhibitory responses were classified according to duration (short: 20–60 msec; long: 100–400 msec). All responses contained an inhibitory component. Responses were further described on the basis of presence and rhythmicity of post-inhibitory excitation. 5. The majority of action potentials evoked from quiescent neurones were of small amplitude (80–150 μV) and occurred in small groups. These characteristics and their occurrence at the onset of inhibition are consistent with the view that all or a proportion of them may be generated by inhibitory interneurones. 6. Only minor differences were observed between response characteristics evoked by stimulation of the corticomedial or basolateral AMY indicating that differential effects of these regions on adenohypophysial hormone secretion are determined at the septopreoptic level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237045
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  • 15
    Digitale Medien
    Digitale Medien
    A cerebellar projection onto the pontine nuclei in the albino rat (1977)
    Springer
    Experimental brain research 30 (1977), S. 149-154 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Dentate and interpositus nuclei ; Pontine gray ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Following removal of a significant part of the dentate nucleus and most of the interpositus nucleus in the rat cerebellum degenerated cerebellopontine fibres are shown to end in three fairly restricted regions in the contralateral pontine gray: in the paramedian position, in the middle and in the lateral third. The three regions are arranged in rostro-caudal longitudinal columns in the caudal three-quarters of the pons and these columns are continuous with one another by regions of scattered degeneration. The fibres appear to end in relation to distal dendrites of the pontine cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237866
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  • 16
    Digitale Medien
    Digitale Medien
    Ultrastructural responses of the hypoglossal nucleus to the presence in the tongue of botulinum toxin, a quantitative study (1977)
    Springer
    Experimental brain research 30 (1977), S. 313-321 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Rat ; Hypoglossal nucleus ; Botulinum toxin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural effects of local injection of botulinum toxin into the left half of the tongue of the rat, were studied quantitatively 35 days postoperatively in the left hypoglossal nucleus. The results showed (1) a decrease in somatic and neuropil bouton numbers because of loss of boutons with symmetrical synapses and clear spherical synaptic vesicles, (2) a decrease in the numbers of dendrite profiles in the neuropil, (3) an increase in the proportion of dendrites and boutons with unusual inclusions, suggestive of profile retraction, (4) an increase in the proportion of profiles which were unusually electron-dense, (5) an increase in the amount of astrocyte, and a growth of astrocyte sheaths around bouton-free neurone surfaces, (6) the presence of occasional microglia, and (7) subastrocytic subsurface cisterns. Control rats injected with boiled toxin had no responses except (3) and (4) above, and then only to a modest extent, possibly due to mechanical damage of a few axons or terminals at the time of injection, or to insufficient inactivation of the toxin by boiling. The results were compared with those at 35 days after axotomy, and it was concluded that botulinum toxin, which interrupts neuromuscular transmission, elicits the same responses in the hypoglossal neurones, as does transection of the hypoglossal nerve, even though earlier studies had discovered no glial replication after botulinum toxin, in contrast to axotomy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237258
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  • 17
    Digitale Medien
    Digitale Medien
    Cholinergic transmission in subcortical and cortical visual centers of rats: No evidence for the involvement of primary optic system (1977)
    Springer
    Experimental brain research 27 (1977), S. 211-219 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual system ; Degeneration ; AChE ; Choline acetyltransferase ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect of unilateral enucleation, ablation of the visual cortex or coagulation of the lateral geniculate nucleus (LGN) upon the activity of choline acetyltransferase (ChAc) and acetylcholinesterase (AChE) in different structures of the visual system of albino rats was studied. The localization and extent of the degeneration pattern were followed up by histological silver degeneration methods. Afferents from the retina project mainly contralaterally to the dorsal and ventral LGN, the pretectal region and the superior colliculus. Afferent fibres from the dorsal LGN enter the visual cortex in area 17 only. Neurons of this area project back ipsilaterally to the LGN and the superior colliculus (SC). No significant decrease in the activity of the cholinergic marker enzyme choline acetyltransferase could be observed under any of the experimental conditions; there was rather a tendency to increased activity in the subcortical centres. AChE as a less specific marker also exhibited no gross changes in activity in the lesioned animals. The results add more direct proof to pharmacological and physiological evidence that ACh is not involved in the synaptic transmission of the direct optic projections in rats, either at the subcortical or at the cortical level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237699
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  • 18
    Digitale Medien
    Digitale Medien
    Responses in the hypoglossal nucleus to delayed regeneration of the transected hypoglossal nerve, a quantitative ultrastructural study (1977)
    Springer
    Experimental brain research 29 (1977), S. 219-231 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Rat ; Hypoglossal nucleus ; Delayed regeneration ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron micrographs of the left hypoglossal nucleus of adult male albino rats were quantitatively analyzed from 9–70 days after allowing the transected left hypoglossal nerve to regenerate after an 84 day delay. Delay was achieved by implanting the proximal stump into already innervated sternomastoid muscle, where no regeneration occurred. Regeneration was then allowed by denervating the sternomastoid. During the regenerative period the initially high number of abnormally electron dense perikarya and dendrites decreased to almost normal values, but no cell removal was seen. This suggested that the degenerate appearance of many profiles after prolonged prevention of regeneration, was reversible. The neuropil bouton and dendrite counts, and the numbers of synapsing boutons per dendrite, increased steadily to normal values from the low values of suppressed regeneration. Somatic bouton frequencies, even though already low, decreased further at 32 days, and later increased but not to normal values. The decrease at 32 days coincided with the loss of many subsurface cisterns, and dispersion of Nissl substance, all suggestive of chromatolysis. Later the subsurface cisterns and Nissl substance returned. It was suggested that the delay of complete recovery of somatic bouton frequencies might be because of lack of sensory information from the denervated muscle into which the hypoglossal nerve was regenerating, or because of abnormally low starting values for the recovery phase. Astrocyte (or, occasionally microglial) sheaths persisted along boutonfree perikaryal surfaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237043
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  • 19
    Digitale Medien
    Digitale Medien
    Cell death in the optic tectum of the developing rat (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 29-34 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Optic tectum ; Rat ; Cell death
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The death of cells was studied by light microscopy in the optic tectum of normal, developing rats. Normal cell death in the tectum during development has previously been described in chickens but not in a mammal. The total period of cell death was from the 20th embryonic day through the 11th postnatal day. During this period the number of dying cells was comparatively small for the first 2 days, reached a peak at birth and then decreased over the next 11 days. In comparison to the number of surviving cells the number of dead cells in each section was small. The dead cells appeared to be randomly distributed in all layers of the optic tectum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315295
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  • 20
    Digitale Medien
    Digitale Medien
    The postnatal development of rat dentate gyrus and the effect of early thyroid hormone treatment (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 335-339 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Autoradiography ; Hippocampus ; Neurogenesis ; Rat ; Thyroid hormone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The postnatal development of the dentate gyrus and the effect of 5 μg/day triiodothyronine treatment was examined by means of tritiated thymidine autoradiography. The polymorph layer of the dentate gyrus is a secondary germinal layer and forms cells for the granular layer. The cell formation in the dentate gyrus was found to be nearly completed on the 21st day, but development ended only in adulthood. Thyroid-hormone treatment did not affect significantly the postnatal cell formation of the dentate gyrus, but resulted in the appearance of a great number of pycnotic cells in the granular layer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318935
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  • 21
    Digitale Medien
    Digitale Medien
    The surface ultrastructure of the habenular complex of the rat (1977)
    Springer
    Anatomy and embryology 152 (1977), S. 43-64 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Habenula ; Ependyma ; Supraependymal cells ; Supraependymal axons ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The surface features of the ependymal lining of the habenular complex in rats, aged between three weeks and nine months, were studied by means of scanning and transmission electron microscopy. The ependyma of the medial habenular nucleus is heavily ciliated, the cilia obscuring underlying substructure in SEM — preparations. On the habenular commissure most cilia are arranged in tufts. Cilia are provided with segmental indentations and occasional apical thickenings. Vesicular protrusions of the ependymal cytoplasm into the ventricular lumen and the frequent occurrence of homogeneous supraependymal globules were interpreted as signs of ependymosecretory activity of nucl. hab. med. Supraependymal cells are most numerous on the anterior and superior surface of the habenular commissure. Cells presenting features identical to Kolmer (epiplexus) cells were identified on the ventricular surface of nucl. hab. med. in one specimen showing degenerative changes of undetermined aetiology in the habenular nuclei. It is therefore suggested that such cells need not necessarily be restricted to the choroid plexus. Supraependymal unmyelinated axons are particularly numerous on both nucl. hab. med. and commiss. hab. They make desmosome contacts (maculae adherentes) with the ependymal plasmalemma. Contacts presenting all features of typical synapses were not encountered. The vesicle population of the axonal profiles mainly comprises 35–50 nm translucent round vesicles besides small numbers of 60–100 nm dense-cored vesicles and large pleiomorphic vesicles. Most probably the axons belong to the well-established dense population of serotonergic axons in the dorsal part of the third ventricle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00341434
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  • 22
    Digitale Medien
    Digitale Medien
    Effect of chronic centrifugation on bone density of the rat (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 223-232 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Bone ; Femur ; Density ; Hypergravity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Alterations in density of the femur of female Sprague-Dawley rats exposed to chronic centrifugation of 2.76 G for 810 days were studied. The density was measured by photon absorptiometry, using a 125I Profile Scanner. The photon absorption measurements were taken: (1) on bone sections from the midshaft of the femur in the anterior, posterior, medial and lateral cortex with the beam path parallel to the shaft axis, and (2) on the femur near the midshaft with the beam path perpendicular to the shaft axis. The latter were correlated with the cross-sectional area in the midshaft. Compared with femora of age-matched rats (age controls) and of rats having body masses comparable to the centrifuged group (weight controls), kept under earth gravity, the chronically centrifuged animals showed on average no significant differences in photon absorption (density) in the four positions in midshaft. The absorption measurements perpendicular to the shaft axis in all groups differe significantly on average. In the relationship to the cross-sectional area there are significant differences between the centrifuged group and the control groups. When cross-sections of equal size are compared, the density of the rat femora is clearly higher in the centrifuged animals than in the control groups. In contrast, the age and weight controls do not differ significantly in density. The results suggest that the increased stress in the rat femora due to centrifugation is reflected in an increased bone density.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00297483
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  • 23
    Digitale Medien
    Digitale Medien
    Absorption of horseradish peroxidase by the principal cells of the large intestines of postnatal developing rats (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 53-62 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Large intestine ; Intestinal absorption ; Postnatal development ; Rat ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The absorption of horseradish peroxidase in the rat large intestine during the postnatal developing period was investigated by cytochemical and ultrastructural methods. In the ceca and ascending colons from 4-, and 5-day-old rats, intraluminaly injected peroxidase became localised on microvilli, in the intracytoplasmic network of the apical tubules and small vacuoles (tubulo-vacuolar system), in the large supranuclear vacuole, in the Golgi apparatus, on the lateral and basal cell membranes of the surface principal cells, and also in the lumen of blood capillaries in the subjacent propria. On the other hand, the protein tracer was not seen in the large intestinal epithelial cells that lack tubulo-vacuolar systems and large supranuclear vacuoles within their cytoplasm. In the descending colons of rats of any postnatal age, the epithelial principal cells are devoid of these membrane systems, and exogenous peroxidase was not detected in the cytoplasm of the principal cells. It is assumed that at least the proximal portion of the large intestine in neonatal animals has the capacity to absorb macromolecular protein through those surface principal cells that have specialized intracellular membrane systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315297
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  • 24
    Digitale Medien
    Digitale Medien
    Influence of adrenalectomy on “Gomori-positive” substances in the hypothalamo-neurohypophysial system of rats heterozygous and homozygous for hypothalamic diabetes insipidus (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 81-89 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Neurosecretion ; Adrenalectomy ; Diabetes insipidus ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The influence of adrenalectomy on the amount of “Gomori-positive” neurosecretory material in the outer layer of the median eminence and in the supraoptico-hypophysial system was studied in normal Long-Evans rats and in Long-Evans rats heterozygous and homozygous for hypothalamic diabetes insipidus. In all non-adrenalectomized rats very few “Gomori-positive” granules were found in the outer median eminence layer. After adrenalectomy the amount of the granules increased markedly in normal Long-Evans rats and only slightly in Long-Evans rats heterozygous for diabetes insipidus. However, no augmentation of the granules occurred in homozygous diabetes insipidus rats. The amount of “Gomori-positive” substances demonstrable in the supraoptic and paraventricular nuclei, in the inner layer of the median eminence, and in the neural lobe of the hypophysis was less in rats heterozygous for diabetes insipidus than in normal Long-Evans rats and the smallest in homozygous diabetes insipidus rats. No differences in the amounts of the substances were observed between adrenalectomized and non-adrenalectomized animals. The findings suggest that the “Gomori-positive” granules occurring in the outer layer of the median eminence of adrenalectomized rats are of similar origin as those of the supraoptico-hypophysial system and represent a vasopressin-neurophysin-complex. The results support the concept that vasopressin is involved in the regulation of ACTH release.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315300
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  • 25
    Digitale Medien
    Digitale Medien
    The fine structure of the ependymal surface of the recessus infundibularis in the rat (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 241-265 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Scanning E.M. ; Third ventricle ; Neurohypophysis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The surface of the recessus infundibularis of the third ventricle has been studied with the scanning and transmission technique in normal and experimental material. Surface specializations such as microvilli, craters and areas of discontinuous lining are described. Supraependymal cells and fibres have been found; some of these cells form wide-meshed networks. The supraependymal fibres may be regular or varicose; the former seem to perforate the ependyma. With the transmission electron microscope the supraependymal cells are divided into three categories: nerve cells, lymphocytes and “dense cells”. Two fibre populations are distinguished: thin profiles (nerve fibres) and thick profiles (nerve terminals). Axosomatic and axoaxonic synapses are described. Synapses between supraependymal fibres and ependyma cells have also been found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318929
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  • 26
    Digitale Medien
    Digitale Medien
    The accessory phrenic nerve in the rat (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 63-69 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Rat ; Phrenic nerve ; Accessory phrenic nerve ; Diaphragmatic myotomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Reinnervation studies of the diaphragm led us to reinvestigate the normal anatomy of the phrenic nerve of the rat. The phrenic nerve originates from the cervical nerve roots C4 and C5. In 16 out of 19 normal rats an accessory phrenic nerve was observed receiving its segmental fibres from C6. The number of myelinated axons of the accessory phrenic nerve varied from 41 to 101 (mean: 64.3, i.e. about 15% of the average number of axons in the common phrenic nerve). The accessory phrenic nerve innervates the dorsal part of the costal and the lateral part of the crural region, whereas the remaining parts of the hemidiaphragm are supplied by the segments C4 and C5. There is no evidence for any additional contribution to the motor innervation of the diaphragm from intercostal nerves.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315298
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  • 27
    Digitale Medien
    Digitale Medien
    The influence of protein-calorie malnutrition on the development of paranodal regions in spinal roots (1977)
    Springer
    Acta neuropathologica 40 (1977), S. 253-257 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Protein-calorie malnutrition ; Rat ; Spinal root ; Paranodal region ; OTAN method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary During the early postnatal development of spinal roots in rats paranodal regions were often found, containing OTAN-positive inclusions in the Schwann cell cytoplasm. The presence of OTAN-positive paranodal regions showed variations in time, which were synchronous for ventral and dorsal roots. Dorsal roots, however, showed a more marked presence during development than ventral roots. Spinal roots of animals submitted to a 50% food restriction, were shown to contain more OTAN-positive paranodal regions than controls. This was true for ventral as well as dorsal roots. It is suggested that crowding of internodal segments could be one factor, determining the presence of paranodal, OTAN-positive material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691963
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  • 28
    Digitale Medien
    Digitale Medien
    Paranodal myelin retraction in protein deficient and normal rats (1977)
    Springer
    Acta neuropathologica 40 (1977), S. 249-252 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Low-protein diet ; Rat ; Peripheral nerve ; Paranodal area ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Young rats, submitted to severe protein restriction were studied concerning the width of intermyelin gaps at the nodes of Ranvier in peripheral nerve fibres. The results gave no proof of increased paranodal myelin retraction in lumbar spinal roots or the sciatic nerves of low-protein rats. Malnourished rats as well as controls showed great interindividual differences as to the presence of nodes with wide inter-myelin gaps.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691962
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  • 29
    Digitale Medien
    Digitale Medien
    Matrix vesicles in newly synthesizing bone observed after ultracryotomy and ultramicroincineration (1977)
    Springer
    Calcified tissue international 23 (1977), S. 185-188 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Matrix vesicles ; Bone ; Ultracrytomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Matrix vesicles were observed in femurs of 8-day-old chick embryos prepared by ultracryotomy. Some of the sections were subjected to ultramicroincineration. The unfixed tissues never came into contact with solutions, and thereby artifacts due to dissolution, redistribution, or rearrangement of the mineral constituents were avoided. In the osteoid, electron dense objects with the size and appearance of matrix vesicles were seen, although limiting membranes were not visible. After ultramicroincineration the vesicles were observed to contain small crystals and a less dense amorphous mineral material which may be the precursor of bone mineral. In addition, a ring of ash enclosed the crystalline and amorphous mineral and appeared to occupy the position of the vesicle membrane as seen in conventionally prepared material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012785
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  • 30
    Digitale Medien
    Digitale Medien
    Magnesium and the mineral metabolism of chick embryo tibiae in organ culture (1977)
    Springer
    Calcified tissue international 24 (1977), S. 93-98 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Magnesium ; Bone ; Mineral ; Chick embryo ; Organ culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Using bone organ culture techniques, three concentrations of magnesium were evaluated for their effects on the mineral mass of embryonic chick tibiae incubated for 3 days with or without a metabolic inhibitor (1 mM iodoacetic acid) added to the media. Varying the medium Mg level from 0.3 to 3.0 mM had little effect on the net increase in mineral in live bones (without the inhibitor), but in dead tibiae (with the inhibitor) there was a marked net decrease in mineral deposition with increasing Mg concentration. Bone Mg mass varied directly with the level of Mg in the medium regardless of whether or not the tibiae were inhibited. Responsiveness to parathyroid hormone (PTH) with regard to mineral loss and increased lactate production was not affected by Mg even in tibiae incubated in Mg-free media. However, PTH-treated bones cultured in Mg-free media had a significantly elevated Mg mass, suggesting that the hormone may have a Mg-conserving effect on bone during severe Mg deficiency. The findings of this study support the hypothesis that bone cells regulate the level of Mg to which newly forming mineral is exposed and that PTH-responsiveness in embryonic chick tibiae is not dependent on the ambient Mg concentration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223301
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  • 31
    Digitale Medien
    Digitale Medien
    The effect of fluoride on bone of rats fed diets deficient in calcium or phosphorus (1977)
    Springer
    Calcified tissue international 22 (1977), S. 9-17 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Fluoride ; Calcium ; Phosphorus ; Mechanical Strength
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Four groups of weanling rats were fed for 2 weeks on a diet sufficient or insufficient in calcium and/or phosphorus. Each group was divided into four subgroups which were offered distilled water supplemented with 0, 50, 75, or 150 ppm fluoride. High levels of fluoride in drinking water inhibited weight gain. This inhibition was less in rats deficient in phosphorus than when normal-phosphorus diets were offered. At a low level, fluoride was without any effect on bone ash, thickness of femoral cortical bone, and mechanical strength, as measured by maximal load, ultimate stress to breaking, and limit of elasticity. Modulus of elasticity was decreased. At higher levels fluoride tended to decrease most of these parameters, except in rats deprived of both calcium and phosphorus. The effect of fluoride was modified by lack of dietary calcium and/or phosphorus and appeared to be weaker in rats deficient in these nutrients. Lack of dietary calcium and/or phosphorus decreased bone strength more than did fluoride content of water and of bone mineral. Concentration of bone ash and thickness of femoral cortical bone were closely correlated with parameters of mechanical strength.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010341
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  • 32
    Digitale Medien
    Digitale Medien
    An interpretation of acute changes in plasma45Ca following parathyroid hormone administration to thyroparathyroidectomized rats (1977)
    Springer
    Calcified tissue international 22 (1977), S. 117-128 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Parathyroid hormone ; Plasma calcium ; Radiocalcium ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Acute changes in plasma calcium and45Ca were studied in young adult male thyroparathyroidectomized (TPTX) rats injected with moderate doses of parathyroid hormone (PTH). For plasma calcium changes, comparison was made between rats fasted or fed prior to PTH injection. For plasma45Ca changes, the effect of the time of administration of the radionuclide was also studied; this included rats injected with PTH 1 h after radionuclide (“1 h45Ca”), 18 h later (“18 h45Ca”) and more than 6 days later (“6 day45Ca”). The results can be summarized as follows: (1) Plasma calcium changes were greater when PTH was injected into “fed” rather than into “fasted” rats. (2) PTH always produced a relative increase (compared to controls tested concurrently) in plasma45Ca concentrations. This increase was the same in the “1 h45Ca” and the “18 h45Ca” groups. (3) Plasma45Ca rose at least temporarily following PTH injection in the “18 h45Ca” group. (4) The45Ca rise following PTH was always greater in “fed” than in “fasted” groups. (5) Plasma45Ca specific activities (S.A.) tended to rise in the “6 day45Ca” group and to fall in the “18 h45Ca” group, following PTH injection. However, the45Ca S.A. was always higher in fed than fasted groups. (6) In a few experiments in which32P was injected with45Ca, specific activity changes in plasma45Ca following PTH injection werenot accompanied by similar changes in32P specific activity. These results could not be adequately explained by PTH effects on bone resorption, but the data supported the postulate that PTH controls plasma calcium concentrations by increasing transport of calcium through the osteocyte-lining cell (osteoblast) bone cell complex from the bone fluid compartment to the ECF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010351
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  • 33
    Digitale Medien
    Digitale Medien
    On the state of anionic groups of demineralized matrices of bone and dentine (1977)
    Springer
    Calcified tissue international 22 (1977), S. 275-284 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Calcium ; Collagen ; Dentine ; Phosphoprotein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Calcium-binding and biochemical studies have been applied to characterize the state of the carboxylate and protein-bound phosphate groups in the EDTA-demineralized matrices of rat bone and dentine. The organic phosphate and carboxylate content of demineralized bone is virtually identical to that of purified steer skin collagen whereas demineralized dentine has a significantly higher phosphate and carboxylate content, presumably due to the presence of an acidic non-collagenous phosphoprotein. Two classes of calcium-binding sites can be detected in demineralized bone, demineralized dentine, and purified, reconstituted collagen. The number of strong calcium-binding sites correlates with the number of protein-bound phosphate groups. Depending on the preparative procedure, seven to nine such sites (per collagen molecule) are present in dentine, and one to two in the purified reconstituted collagen and in bone. The binding constant for the dentinal sites (1.1×104 M−1), however, is 20 times greater than that for bone or reconstituted collagen fibrils from skin. We tentatively conclude that the strong calcium-binding site in bone and reconstituted collagen is of the form protein-PO 4 − Ca++ whereas in dentine it is of the form the weak binding sites in bone and dentine are of the form protein-COO-Ca++; and that approximately 160 of the 217 carboxylate groups of the collagen molecules of dentine or bone are present as electrostatic linkages of the form protein-COO−+H3N-protein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010366
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  • 34
    Digitale Medien
    Digitale Medien
    Strain related electrical potentials recorded in vitro and in vivo (1977)
    Springer
    Calcified tissue international 22 (1977), S. 315-327 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Bioelectricity ; Strain ; Locomotion ; Osteoporosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Using wet dead specimens it was possible to show that the size and form of strain-related electrical potentials on the surface of sheep radii were related both to the amount of strain, and the strain rate, over the range of these recorded during locomotion. Using the same electrode and amplifier system in vivo changes in surface strain and surface charge were recorded from the radius of three sheep during locomotion. During slow locomotion electrical changes were negligible. At medium speed they were most variable, and profoundly influenced by small alterations in the timing and pattern of strain change. When locomotion was fast the electrical waveform reflected fairly faithfully the changes in strain on the bone surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010370
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  • 35
    Digitale Medien
    Digitale Medien
    Bone mineral content in the forearm after fracture of the upper limb (1977)
    Springer
    Calcified tissue international 22 (1977), S. 329-331 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Fracture ; Mineral
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract The bone mineral content was measured by gamma absorptiometry in patients who had sustained fractures of the upper limb. Measurements were taken on the shafts of the forearm and in the trabecular bone immediately proximal to the wrist. Fractures of the surgical neck of the humerus and fractures of the shaft of the humerus did not significantly influence the bone mineral content of the ipsilateral forearm. Fracture of the radius and the ulna, however, caused a 15% loss of the bone mineral content in the trabecular bone proximal to the wrist, whereas the mineral content on the shafts of the fractured forearms increased or decreased depending on the fracture site. The findings suggest that measurements of bone mineral content of the forearm are not necessarily invalidated if there has been a fracture of the same limb. Only if the forearm itself is fractured should measurements on this site be avoided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010371
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  • 36
    Digitale Medien
    Digitale Medien
    The ultrastructure of the extracellular phase of bone as observed in frozen thin sections (1977)
    Springer
    Calcified tissue international 23 (1977), S. 215-223 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Amorphous mineral ; Bone ; Electron microscopy ; Ultracryotomy ; Ultramicro-incineration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15–30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 μm in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO4 vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012788
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  • 37
    Digitale Medien
    Digitale Medien
    A new tracer method for the calculation of rates of bone formation and breakdown in osteoporosis and other generalised skeletal disorders (1977)
    Springer
    Calcified tissue international 22 (1977), S. 191-206 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Calcium ; Strontium ; Apposition ; Tracer analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract 1. Evidence has accumulated that the rate of acceretion (A) of calcium to bone is the sum of two fluxes; apposition involving the laying down of new bone and augmentation which is the result of slow exchange of non-surface bone calcium with plasma calcium pools as the result of solid state diffusion. 2. A method has been devised for separating A into its two components. It requires the use of45Ca or, for clinical studies,85Sr as a calcium tracer. Studies which are initiated with a combined accretion rate-calcium balance study, are concluded with an estimate of the exponent of the power function which has been found to describe the whole body retention of tracer from the second month onward. 3. The impulse response function of the skeleton for the tracer is then calculated, making the assumption that in any uniform volume of bone, osteoclastic resorption is a first order process. Making in addition certain simplifying assumptions, which are shown to have a modest influence on the final results, a mean rate of bone resorption can be calculated using a development of the well known Stewart-Hamilton formula. The apposition rate is calculated as the sum of the resorption rate and the calcium balance. Augmentation and diminution, defined as equal and opposite exchange processes, are given by the difference between A and the apposition rate. 4. The results of our first thirteen studies in normal subjects and patients with metabolic bone disease are presented, together with analyses of some data from the literature. It is concluded that the development of an atraumatic method for measuring rates of bone formation and resorption in the whole body would be an important advance in the study of metabolic bone disease, and this work is presented so that critical comparisons may be initiated between this tracer method and independent histological methods for measuring these parameters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010358
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  • 38
    Digitale Medien
    Digitale Medien
    Initial studies on the crystallinity of the mineral fraction and ash content of isolated human and bovine osteons differing in their degree of calcification (1977)
    Springer
    Calcified tissue international 23 (1977), S. 7-11 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Electron spin resonance ; Crystallinity ; Bone ; Osteons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Several groups containing 10–15 isolated osteons differing in their degree of maturity were analysed. Samples were isolated from undecalcified human and bovine bone sections. The crystallinity coefficient, defined as the ratio of the number of radiation-induced paramagnetic defects in the crystalline lattice of hydroxyapatite to the total ash content, was calculated. The results were compared with measurements performed on fragments of total cortical bone, primary periosteal bone, and inner circumferential lamellar bone. The results show a higher crystallinity of fully calcified osteons as compared with that found at the initial stage of calcification. No differences in the ash content were observed between human osteons, from different stages of calcification evaluated morphologically and by X-ray absorption. These differences were evident when bovine osteons differing in their stage of calcification were compared. Human fully calcified osteons contain 60% ash and their crystallinity coefficient is 52.1. Human osteons at the initial stage of calcification contain 57% ash and their crystallinity coefficient is 40.6. The same parameters for fully calcified bovine osteons and for bovine osteons at the initial stage of calcification are 59% ash, 62.6 crystallinity coefficient and 46% ash, 43.0 crystallinity coefficient, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012760
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  • 39
    Digitale Medien
    Digitale Medien
    Relations between tensile impact properties and microstructure of compact bone (1977)
    Springer
    Calcified tissue international 24 (1977), S. 65-72 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Strength ; Tension ; Microstructure ; Osteon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Standardized human and beef femoral compact bone specimens were tested in tensile impact and the dynamic mechanical properties were determined. The microstructure of 45 beef and 47 human bone specimens were examined histologically to determine if there is a structural basis to account for strength differences in the bone samples. Strong negative correlations were obtained between the maximum stress and the percentage area of secondary osteons in each specimen. For human bone samples, the energy absorption capacity and the modulus of elasticity were also found to have strong negative correlations with the percentage area of secondary osteons present in each specimen. Linear regression equations were obtained describing the impact strength properties in terms of the percentage areas of secondary osteons and cavities in the samples. Fracture surfaces of the tested bone specimens were examined in a scanning electron microscope. Most surfaces exhibited a fairly rough texture indicating a quasi-cleavage type of failure. Fractographic analysis of bone fracture surface was helpful in understanding the micromechanics of bone fracture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223298
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  • 40
    Digitale Medien
    Digitale Medien
    Density and composition of trabecular and cortical bone in perinatally irradiated beagles with chronic renal failure (1977)
    Springer
    Calcified tissue international 24 (1977), S. 99-104 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Density ; Composition ; Renal osteodystrophy ; Dogs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Bone density and composition were studied in trabecular and cortical bone from control 2 and 4 year old beagles and those which had various degrees of renal failure as a result of perinatal irradiation. Changes in the two types of bone were qualitatively similar but consistently greater in trabecular bone. In a group identified as markedly uremic, the decrease (P〈0.025) from control levels in specific gravity was about 4 times greater in trabecular than in cortical samples. The decrease (P〈0.025) in grams of ash/ml was 9% in trabecular bone and 2% in cortical bone. These changes were associated with an increase (P〈0.001) in water content and, on a percent by volume basis, approximately equal decreases in ash (P〈0.025) and combustible matter (P〈0.025). In a mildly uremic group there were similar trends in mean values but the only significant difference was an increase (P〈0.001) in trabecular bone water.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223302
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  • 41
    Digitale Medien
    Digitale Medien
    Effect of salmon calcitonin infusion on plasma concentrations of recently administered45Ca (1977)
    Springer
    Calcified tissue international 24 (1977), S. 201-208 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Calcitonin ; Plasma calcium ; Radiocalcium ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The effect of intravenous salmon calcitonin (SCT) infusion on the net rate of loss from plasma of recently injected45Ca has been studied in conscious fasted rats, some of which had been previously thyroparathyroidectomized (TPTX). The45Ca was injected 10 h prior to or 1 or 2 h after the initiation of the infusion. Salmon calcitonin (0.05–0.2 MRC mU/g body weight/h) infusion produced the expected hypocalcemia and hypophosphatemia. The drop in plasma calcium levels produced by the hormone was lowered further by the addition of phosphate to the infusate. Plasma45Ca changes, during SCT infusion, followed a biphasic pattern when the radionuclide injection preceded SCT infusion by 10 h. During the first part of the infusion, the rate of loss of45Ca from plasma was greater in SCT-treated than in control rats. Later, this pattern reversed, and the rate of loss of45Ca from plasma became slower in SCT-treated animals. If45Ca was injected after SCT infusion was initiated only the second phase of the biphasic effect was observed; i.e., disappearance of45Ca from plasma was slower in SCT-infused than in control rats. These data are considered to support the hypothesis that rapid and opposing calcium fluxes exist between bone fluid and plasma, and that calcitonin acts by decreasing the calcium efflux from bone fluid. The calcium moved in this efflux system includes some that has only recently entered bone fluid from plasma. This is the explanation given for the initial decrease in plasma45Ca concentrations following SCT infusion. The reverse effect in the second phase can be explained as the result of a secondary reduction in calcium influx to bone fluid from plasma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223317
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  • 42
    Digitale Medien
    Digitale Medien
    Absorption spectra of bone (1977)
    Springer
    Calcified tissue international 23 (1977), S. 113-114 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Absorption Spectra ; Collagen ; Hydroxyapatite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Absorption spectra of human bone and its two major constituents (collagen and apatite) were obtained in the wavelength region extending from 2000 to 12,000 Å. In the last two cases a, minimum transmission (maximum absorption) was uniformly observed in the ultraviolet region. The two samples after exposure to ultraviolet radiations show a shift in the peak positions. Absorption peaks in the total bone spectra are not reproducible in its two constituents. After exposure to UV radiations the position of maximum absorption is displaced. A possible interpretation of the observed results is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012774
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  • 43
    Digitale Medien
    Digitale Medien
    Comparison of effects of parathyroidectomy and ethane-1-hydroxy-1,1-diphosphonate (EHDP) administration upon bone synthesis of hydroxyproline and urinary excretion of hydroxyproline in rats (1977)
    Springer
    Calcified tissue international 23 (1977), S. 115-119 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Parathyroidectomy ; Diphosphonates ; Bone ; Collagen ; Hydroxyproline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) may impair mineralization and reduce turnover of bone. However, its administration has been shown to lead to an accumulation of osteoid in both man and the rat. Using rats, the effects of surgical parathyroidectomy and administration of EHDP (30 mg EHDP/kg body weight by subcutaneous injection daily for 5 days) upon bone composition, uptake of3H-proline into hydroxyproline in bone and the subsequent urinary excretion of labelled and unlabelled hydroxyproline have been compared. Both parathyroidectomized (PTX) rats and EHDP-treated animals accumulated more hydroxyproline in bone and excreted less total urinary hydroxyproline than sham-PTX control animals, the changes induced by EHDP being of greater magnitude than those induced by surgical parathyroidectomy. Skeletal buildup of hydroxyproline was associated with decreased catabolism of mature collagen rather than enhanced synthesis of hydroxyproline in bone. EHDP administration, although decreasing urinary excretion of newly synthesised hydroxyproline, did not alter the skeletal synthesis of hydroxyproline as measured by uptake of3H-proline. In all parameters measured, responses to EHDP were similar in PTX and sham-PTX rats. It is concluded that depression of parathyroid hormone mediated bone turnover may have contributed to, but did not fully account for, the lowering of bone turnover and changes in bone composition induced by EHDP in sham-PTX rats in the present experiment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012775
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  • 44
    Digitale Medien
    Digitale Medien
    Plasma proteins present in human cortical bone: Enrichment of theαHS-glycoprotein (1977)
    Springer
    Calcified tissue international 22 (1977), S. 27-33 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Protein ; Bone ; Blood plasma ; Dentine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract The spectrum of plasma proteins present in human cortical bone and permanent dentine has been determined. One plasma glycoprotein, theαHS-glycoprotein, was found to be present at a high concentration in both bone and dentine and was shown to be concentrated in the mineralized tissues with respect to the other plasma proteins by factors of between 30 and 100. In this respect theαHS-glycoprotein is analogous to the G2B-glycoprotein and α-glycoprotein of bovine and rabbit b one, respectively. The binding ofαHS-glycoprotein and albumin to calcium phosphates generated within serum samples has been studied at different serum: precipitate ratios. In each case all theαHS-glycoprotein was removed from the samples and theαHS-glycoprotein was concentrated with respect to albumin by factors ranging from 370 at the highest serum: precipitate ratio to 25 at the lowest ratio. The plasmaαHS-glycoprotein concentrations of patients with Paget's disease of bone were shown to be substantially lower than the normal range, with significant negative correlation between theαHS-glycoprotein concentration and the plasma alkaline phosphatase activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010343
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  • 45
    Digitale Medien
    Digitale Medien
    Plasma fluoride and enamel fluorosis (1977)
    Springer
    Calcified tissue international 22 (1977), S. 77-84 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Fluoride ; Blood plasma ; Enamel mineralization ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract It is postulated that tissue fluid F concentrations are the primary determinants of fluoride effects on bones and developing teeth and that these concentrations are dependent on, or mirrored by, blood plasma F. It has earlier been shown that the plasma F levels are dependent on the dietary F supply as well as on skeletal F concentration. Fasting and post-ingestion or postinjection plasma F levels have been determined in rats on F doses that cause different degrees of enamel fluorosis. The results indicate that temporary peak values rather than elevated fasting values are responsible for the occurrence of enamel fluorosis and that the peak values must approach about 10 μM in order to block enamel formation by the ameloblasts. The diagnostic and prognostic importance of plasma F determinations is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010348
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  • 46
    Digitale Medien
    Digitale Medien
    A model-independent comparison of the rates of uptake and short term retention of47Ca and85Sr by the skeleton (1977)
    Springer
    Calcified tissue international 22 (1977), S. 183-189 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Calcium ; Strontium ; Bone ; Mathematical modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract 1. A method has been devised for comparing the impulse response functions of the skeleton for two or more boneseeking tracers, and for estimating the contribution made by measurement errors to the differences between any pair of impulse response functions. 2. Comparisons were made between the calculated impulse response functions for47Ca and85Sr obtained in simultaneous double tracer studies in sixteen subjects. Collectively the differences between the47Ca and85Sr functions could be accounted for entirely by measurement errors. 3. Because the calculation of an impulse response function requires fewera priori assumptions than other forms of mathematical analysis, and automatically corrects for differences induced by recycling of tracer and non-identical rates of excretory plasma clearance of tracer, it is concluded that differences shown in previous in vivo studies between the fluxes of*Ca and*Sr into bone can be fully accounted for by undetermined oversimplifications in the various mathematical models used to analyse the results of those studies.85Sr is therefore an adequate tracer for bone calcium in most in vivo studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010357
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  • 47
    Digitale Medien
    Digitale Medien
    An x-ray diffraction investigation of age-related changes in the crystal structure of bone apatite (1977)
    Springer
    Calcified tissue international 22 (1977), S. 219-226 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Hydroxyapatite ; Bone ; X-ray Diffraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Evidence relating to the existence of crystalline bone mineral in vivo is considered, and bone apatite crystal structure investigated using an x-ray powder diffraction technique. Specimens of femoral compacta excised post-mortem from male and female subjects ranging from 3 1/2 years to 87 years of age have been studied. Values of the ratio c/a of bone apatite crystal cell axes for females are significantly higher (p〈0.05) than for males. Moreover, significant change of c/a with age is observed for males (p=0.0005) but not for females (p=0.30). Differences in c/a are interpreted as indicating substitution of constituent ions in the bone apatite crystals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010360
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  • 48
    Digitale Medien
    Digitale Medien
    Ethane-1-hydroxy-1,1-diphosphonate (EHDP) effects on incorporation and accumulation of osteoclast nuclei (1977)
    Springer
    Calcified tissue international 22 (1977), S. 243-252 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Diphosphonate ; Bone ; Osteoclasts ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract Male rats weighing 100 g were injected with vehicle (control group), 0.4 or 4.0 mg/kg/day of ethane-1-hydroxy-1,1-diphosphonate (EHDP). Beginning after 6 days of EHDP treatment all rats received six subcutaneous injections of3H-thymidine at 8 h intervals. The multiple labeling index of autoradiographically defined labeled cells was determined for the osteoprogenitor cells of the primary spongiosa of the proximal tibial metaphysis. The osteoclasts in the proximal tibial metaphysis were assayed for population parameters and incorporation of labeled nuclei at sequential intervals after the administration of3H-thymidine. After 6 days of EHDP pre-treatment the multiple labeling index of the osteoprogenitor cells was reduced with 4.0 mg/kg/day dose of EHDP. At the beginning of the experimental kinetic sampling period, after the 6 days of EHDP pre-treatment, EHDP treatment resulted in significant increases in the numbers of osteoclasts, nuclei per osteoclast profile, and total osteoclast nuclei. During the sampling period, the 4.0 mg/kg/day dose of EHDP caused further increases in the number of total osteoclasts. EHDP treatment caused a marked increase in the rate of incorporation and accumulation of3H-thymidine-labeled nuclei in osteoclasts. Thus, EHDP causes an accelerated rate of osteoclast production from precursor cells in spite of its ability to slow bone resorption. Although the origin of osteoclast nuclei is not clear, the kinetic data from this study suggests that osteoclast nuclei are not arising from osteoprogenitor cells or osteocytes in the EHDP-treated animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010363
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  • 49
    Digitale Medien
    Digitale Medien
    Movement of125I albumin and125I polyvinylpyrrolidone through bone tissue fluid (1977)
    Springer
    Calcified tissue international 23 (1977), S. 103-112 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Albumin ; Polyvinylpyrrolidone ; Tissue fluid ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The passage of tissue fluid through cortical bone has been investigated using radioactively labelled macromolecules as markers. The results suggest that in the cortex of young rabbit femur the movement of tissue fluid is in the same net direction as blood, mainly from the endosteal to the periosteal surface. Some albumin is incorporated from extravascular tissue fluid into calcified matrix at sites of bone formation. Polyvinylpyrrolidone, average molecular weight 35,000 is able to pass through extravascular tissue fluid in bone but isnot incorporated into calcified matrix. In rabbits made vitamin D deficient, much less albumin is retained in regions of bone formation than is the case with controls. Albumin adsorbs to the surface of calcium phosphate precipitates and it is suggested that this mechanism may be mainly responsible for its incorporation into bone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02012773
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  • 50
    Digitale Medien
    Digitale Medien
    Ultrahistochemical analysis of glycosaminoglycan hydrolysis in the rat periodontal ligament (1977)
    Springer
    Calcified tissue international 24 (1977), S. 143-149 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bone ; Periodontal ligament ; Bone resorption ; Aryl sulfatase ; Mineralization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The distribution of aryl sulfatase in the rat periodontal ligament was investigated by ultrastructural histochemistry. In the periodontal ligament aryl sulfatase was localized specifically in osteoclasts and in vicinal perivascular macrophages. Macrophages associated with bone formation did not stain. The authors interpret this specificity as a potential marker for osteoclast differentiation from macrophages — or as a further indication of the capacity of macrophages to modulate their enzymatic complement in response to the environment. To explain the absence of aryl sulfatase in areas of bone formation we suggest that different sulfate esters are mobilized from resorbing and mineralizing matrices, and that only the enzyme associated with bone resorption is histochemically detectable with the artificial substrates currently used.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223308
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  • 51
    Digitale Medien
    Digitale Medien
    An X-ray study of the paracrystalline nature of bone apatite (1977)
    Springer
    Calcified tissue international 24 (1977), S. 243-248 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Paracrystallinity ; Hydroxyapatite ; Bone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary X-ray diffraction patterns from oriented bone sections show that the crystalline apatite content of untreated mature cortical bovine bone has, in fact, a paracrystalline structure (i.e., no long range order). There is anisotropy in both lattice distortions and the sizes of the coherently diffracting domains. The paracrystalline mean distance fluctuations, (g) were found to be 1.5 (±0.1)% and 2.9 (±0.2)% for the basal and prism planes respectively, the corresponding paracrystalline sizes being 220 (±20) and 70 (±10) Å. The paracrystalline structure became more ordered above 600°C, suggesting the association of hydroxyl and possibly carbonate and other ions with the paracrystalline structure. The paracrystalline model for bone apatite helps explain anomalies between X-ray and electron microscope measurements of crystal size and also some of the biological functions of the crystalline apatite.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223323
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  • 52
    Digitale Medien
    Digitale Medien
    Lamellar organisation in the rat hippocampus (1977)
    Springer
    Experimental brain research 28 (1977), S. 335-344 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Hippocampus ; Rat ; Lamellae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A series of experiments was conducted in the urethane anaesthetised rat to determine the organisation of some hippocampal pathways in this species, using stimulating and recording microelectrodes to elicit and record population spikes. It was found that the mossy fibres, alvear fibres and perforant path were clearly arranged in a lamellar fashion. Lamellar organisation could not be demonstrated for the afferents in the stratum radiatum which include the Schaffer collaterals. It was concluded that hippocampal organisation in this species essentially resembles that in the rabbit and cat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235715
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  • 53
    Digitale Medien
    Digitale Medien
    An automated method for studying exploratory and stereotyped behaviour in rats (1977)
    Springer
    Psychopharmacology 52 (1977), S. 271-277 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Rat ; Exploratory behaviour ; Stereotyped behaviour ; Hole-board ; dl-Amphetamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A technique is described for studying exploratory as well as stereotyped behaviour in rats using an automated hole-board. Both visual and automated recordings can be employed using the technique. Hole dipping is monitored automatically using an infra-red detector system. Repetitive patterns of hole-dipping are used as parameters of stereotyped behaviour while the more random patterns of hole-dipping are used as parameters of exploration. There was a high significant correlation between the records of hole-dipping behaviour as recorded visually and automatically. There was also a high significant correlation between the measures of repetitiveness/randomness of hole-dipping behaviour from automatic and visual recordings. The pattern and levels of hole-dipping conformed with expectations both as regards changes with time and with increasing doses of dl-amphetamine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00426711
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  • 54
    Digitale Medien
    Digitale Medien
    Naloxone-induced or postwithdrawal abstinence signs in Δ9-Tetrahydrocannabinol-Tolerant rats (1977)
    Springer
    Psychopharmacology 55 (1977), S. 243-249 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Abstinence syndrome ; Tolerance ; Physical dependence ; Rat ; THC ; Morphine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ten rats were injected s.c. with THC twice daily for 5 weeks in increasing doses. In the last 3 weeks they received 40 mg/kg THC in each administration. Ten control rats received the same amount of vehicle by the same route for the same period. The comparison of rectal temperatures of the first and fifteenth days showed that a very pronounced tolerance developed to the hypothermic effect of THC. The administration of naloxone on the 22nd and 31st days precipitated an opiatelike abstinence syndrome. The termination of the drug administration on the 35th day also produced a similar withdrawal syndrome. The most common signs of abstinence syndrome in THC-treated animals were teeth chattering, defecation, urination, dyspnea, and complete palpebral closure. Although the frequency of the incidence of the following signs were not high, they have been observed only in THC-treated animals: chewing, tremors on the face, escape behavior, jumping, eating of objects, biting of fingers, and sniffing. During abstinence, an increased locomotor activity was recorded by an activity-meter. Similarly, the total amount of excreted feces and urine was higher in the THC group than in the controls. Both abstinence scores and increased motility exhibited the peak in the 48th h of withdrawal. Some similarities between the effects of THC and morphine have been reviewed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00497855
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  • 55
    Digitale Medien
    Digitale Medien
    On the secretagogue effect of dibutyryl cyclic AMP in the rat exocrine pancreas (1977)
    Springer
    Pflügers Archiv 372 (1977), S. 69-76 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Dibutyryl cyclic AMP ; Pancreas ; Rat ; Secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary DbcAMP≥0.1 mM induces the discharge of exportable enzymes from rat pancreas fragments incubated in vitro. This effect is qualitatively similar to the action of physiological secretagogues acting via hormone receptors: 1) it is accompanied by the appearance of exocytotic images at the acinar cell apex; 2) it is energy dependent but energy supply is low while that required for the carbamylcholine or caerulein response is high and can only be afforded by oxidative phosphorylation; 3) it is calcium dependent, but no alteration of inward or outward calcium movement can be observed; 4) it is altered by agents known to disrupt the microfilamentous microtubular system [41]. However, the secretory response to DbcAMP is quantitatively less than that obtained with hormonal stimuli. A damaging effect of DbcAMP on pancreatic acinar cells is ruled out on histological and biochemical grounds: there is no significant leakage of LDH; protein synthesis, 2-deoxy-d-glucose andl-leucine uptake are unaltered. The secretagogue effect of DbcAMP is reversible, dose-related and specific. It is not mediated by neuro-transmitter release or by interaction with their receptors. The evidence presented points to a direct interaction of DbcAMP on the pancreatic acinar cell and suggests the last step of the secretory cycle as the most probable site of action of the nucleotide derivative.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00582208
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  • 56
    Digitale Medien
    Digitale Medien
    Relative organ blood flow in rats exposed to intermittent high altitude hypoxia (1977)
    Springer
    Pflügers Archiv 368 (1977), S. 111-115 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Altitude ; Myocardium ; Regional blood flow ; Blood volume ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Circulating blood volume, cardiac output and relative organ perfusion changes were studied, using the Sapirstein method of86Rb tissue uptake, in male 75-day-old rats exposed to intermittent high altitude hypoxia (gradually up to 7000 m, 4 h daily, 5 days a week; the total number of exposures was 24). Intermittent hypobaric exposure caused a significant rise of the erythrocyte volume, whereas the plasma volume remained unchanged. The relative perfusion of the left and particularly of the right ventricular myocardium, as well as of the spleen, liver, lung, small intestine and skeletal muscle, was significantly higher. The cardiac output determined in other experimental animals similarly treated was significantly higher after 24 exposures to the intermittent high altitude hypoxia. We suggest that these changes are triggered by tissue hypoxia and a greater blood flow demand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01063462
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  • 57
    Digitale Medien
    Digitale Medien
    Determination of oxytetracycline induced fluorescence and autofluorescence as an indicator of age and sex differences in rat femur (1977)
    Springer
    Pflügers Archiv 370 (1977), S. 77-80 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Bone ; OTC induced fluorescence and autofluorescence ; Intensity and spectrofluorometry ; Age and sex relationship
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Simple and rapid methods for the determination and detection of autofluorescence and oxytetracycline (OTC) induced fluorescence in powdered and intact bone (without previous chemical extraction of the antibiotic) were used to estimate age and sex related differences in the rat femur. The autofluorescence always had collagen characteristics; it increased with age and was not sex dependent. The intensity of OTC induced fluorescence decreased with age, being higher in males than in females. In the oldest animals, however a slight increase in the fluorescence intensity was observed, and sex differences disappeared. The spectrofluorometric measurements of intact femora indicate a higher OTC retention on the bone surface of young animals and adult males but not in adult females. The results indicate that the determination of OTC retention in the bone using our quantitative fluorometric method and the detection of OTC deposition at bone surface using a spectrofluorometric technique can be a sensitive and inexpensive tool for experimental studies of bone changes in physiological and pathological conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00707949
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  • 58
    Digitale Medien
    Digitale Medien
    Fever in rats after intravenousE. coli endotoxin administration (1977)
    Springer
    Pflügers Archiv 368 (1977), S. 125-128 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Endotoxin ; Rat ; Fever ; Anti-endotoxin system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In conscious unrestrained rats, at an ambient temperature of 22°C, oesophageal temperature was measured and temperature effect of single and repeated intravenous injection ofE. coli endotoxin was examined. The first injection of endotoxin in a dose of 10.0 μg/rat did not change the rat body temperature. The second injection of this dose in the same animals repeated after 48 h produced fever. With following injections the fevers observed were less pronounced. The absence of fever after a single injection of endotoxin was accompanied by the rapid loss of pyretic activity of the rat plasma samples (bioassayed in rabbits). When fever was observed (48 h interval between endotoxin injections) the pyretic activity of the rat plasma remained unchanged for 90 min following endotoxin injection. It was concluded that after a single injection endotoxin is rapidly detoxified in the rat circulation while this process does not take place after the second endotoxin injection (48 h interval). The process of endotoxin detoxification can be depressed by the pretreatment with nitrogen mustard. Analysis of changes of skin temperature following endotoxin injections and the influence of aspirin on endotoxin-induced fever suggest that the fever observed was of central origin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01063464
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  • 59
    Digitale Medien
    Digitale Medien
    Presence of type III collagen in bone from a patient with osteogenesis imperfecta (1977)
    Springer
    European journal of pediatrics 125 (1977), S. 29-37 
    Details
    ISSN: 1432-1076
    Schlagwort(e): Osteogenesis imperfecta ; Collagen types ; Bone ; In vitro study ; Immunofluorescence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Samples of bone from a patient with osteogenesis imperfecta were found to synthesize and contain type III collagen as well as type I collagen. Normal bone contains only type I collagen except in the lining cells of the bone marrow cavities. In the patient's tissue, type III collagen was localized in nonfibrillar structures in discrete areas of the bone. These and previous studies indicate that certain types of osteogenesis imperfecta may be caused by a failure of normal bone maturation and the sites in which the type III collagen is found appear to be defects in the bone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00470603
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  • 60
    Digitale Medien
    Digitale Medien
    Biochemical and morphological changes in some organs of rats in nickel intoxication (1977)
    Springer
    Archives of toxicology 37 (1977), S. 159-164 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Nickel ; Rat ; Toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zu verschiedenen Zeiten nach täglicher Zufuhr von Nickelsulfat an Ratten wurden Leber, Niere, Hoden und Herzmuskel auf biochemische und histologische Änderungen untersucht. Während sich in der Initialphase noch keine signifikanten Veränderungen nachweisen ließen, traten nach längerer Exposition deutliche enzymatische und histopathologische Veränderungen in allen vier untersuchten Organen auf. Das Ausmaß der Organläsionen zeigte einen direkten Zusammenhang mit der Behandlungsdauer.
    Notizen: Abstract Biochemical and histological alterations in liver, kidney, testis and myocardium of albino rats were investigated at various intervals after daily administration of nickel sulphate. No significant changes were observed during the initial periods of the treatment, but longer exposures produced marked enzymatic and histopathological alterations in all the four organs examined. The severity of the histological lesions was found to be directly related to the duration of the treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00293867
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  • 61
    Digitale Medien
    Digitale Medien
    Levels of sulfhydryls and sulfhydryl-containing enzymes in brain, liver and testis of manganese treated rats (1977)
    Springer
    Archives of toxicology 37 (1977), S. 319-325 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Sulfhydryls ; Enzymes ; Brain ; Liver ; Testis ; Manganese ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Wirkung von Mangan auf Sulfhydrylgruppen und SH-enthaltende Enzyme in Gehirn, Leber und Hoden von Ratten wurde untersucht. Mangan verminderte den Gehalt an Nicht-Eiweiß-SH und hemmte die Glucose-6-phosphatdehydrogenase sowie die Glutathionreduktase in diesen Geweben. In Gehirn, Leber und Hoden der Mn-behandelten Tiere war der Mn-Gehalt signifikant erhöht.
    Notizen: Abstract The effect of manganese on sulfhydryls and sulfhydryl-containing enzymes in brain, liver and testis of rats was investigated. Manganese produced lowering in the contents of non-protein sulfhydryl groups and inhibited the activity of glucose-6-phosphate dehydrogenase and glutathione reductase in these tissues. The contents of the metal increased significantly in brain, liver and testis of manganese administered rats. The significance of these findings is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00330824
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  • 62
    Digitale Medien
    Digitale Medien
    Zur Toxikologie von Carbromal (1977)
    Springer
    Archives of toxicology 37 (1977), S. 275-288 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Carbromal ; Bromoethylbutyramide ; Ethylbutyrylurea ; Rat ; Pharmacokinetics ; Smooth muscle ; Carbromal ; Carbromid ; Äthylbutyrylharnstoff ; Ratte ; Pharmakokinetik ; glatter Muskel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Oral verabreichtes Carbromal und Carbromid wurden bei Ratten in Dosen unter 20 mg/kg rasch aus dem Magen-Darmtrakt aufgenommen, aus dem Dünndarm 5–8mal rascher als aus dem Magen. Die enterale Resorption von Carbromaldosen größer als 20 mg/kg verlief wesentlich langsamer. Dies ist hauptsächlich auf eine verzögerte Magenentleerung zurückzuführen. Sowohl Carbromal als auch Carbromid hemmten in vitro den Tonus und die durch Acetylcholin induzierte Kontraktion glatter Muskeln des Magenfundus. Carbromal und Carbromid fanden sich im Organismus in gleicher Konzentration in Serum, Gehirn und Skelettmuskulatur. Im Fettgewebe wurden dreimal höhere Werte gemessen. Die Konzentrationen beider Stoffe fallen in den untersuchten vier Organen mit der gleichen Geschwindigkeit wieder ab. Es lassen sich daher mit Hilfe der leicht zu messenden Serumkonzentrationen rasch die im Organismus verteilten Mengen beider Substanzen ermitteln. Intraperitoneal injizieŕtes Carbromal und Carbromid verlassen Serum und Gehirn mit einer Halbwertzeit von 3–4 h, Äthylbutyrylharnstoff mit einer Halbwertzeit von 5–7 h. Carbromal, Carbromid und Äthylbutyrylharnstoff werden von der Ratte rasch und nahezu vollständig metabolisiert. In Urin und Kot erschienen nur Spuren dieser Substanzen. Für eine Sekretion von Carbromal und seinen beiden Metaboliten in den Magen ergab sich kein Anhalt. Die Ergebnisse werden im Hinblick auf die akute Carbromalvergiftung beim Menschen diskutiert.
    Notizen: Abstract Oral doses up to 20 mg/kg of carbromal and of bromoethylbutyramide were rapidly absorbed in the rat. Absorption from the stomach ligated at the pyloric end was 5–8-fold less than absorption of carbromal injected directly into the small intestine. Oral doses greater than 20 mg/kg of carbromal disappeared more slowly from the gastro-intestinal tract because gastric emptying was delayed. Both carbromal and bromoethylbutyramide were able to reduce the basal tone and the acetylcholine-induced contraction of isolated rat fundus strips. Carbromal and bromoethylbutyramide distributed evenly between serum, brain and skeletal muscle. Concentrations in adipose tissue were three times those in the other three tissues. Concentrations of both carbromal and of bromoethylbutyramide in all four tissues declined at the same rate. Thus, serum concentration of either compound may be used to estimate the total body content. Intraperitoneally injected carbromal, bromoethylbutyramide and ethylbutyrylurea disappeared from the brain and from the serum with a half-life of 3–4 h and 5–7 h, respectively. Traces only of unchanged carbromal, bromoethylbutyramide, or ethylbutyrylurea were excreted with urine or feces indicating rapid and extensive biotransformation of the three compounds in this species. No evidence was obtained of secretion of either carbromal or its two metabolites into the lumen of the stomach. The findings are discussed as to their relevance for acute carbromal poisoning in humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00330819
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  • 63
    Digitale Medien
    Digitale Medien
    The effect of mercuric chloride on the excretion of two urinary enzymes in the rat (1977)
    Springer
    Archives of toxicology 37 (1977), S. 219-225 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Inorganic mercury ; Renal enzyme excretion ; Chelating agents ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Wirkung von intravenös verabreichtem HgCl2 auf die renale Ausscheidung von alkalischer Phosphatase (AP) und Leucinaminopeptidase (LAP) wurde an Ratten untersucht. Am ersten Tag nach Hg-Injektion erfolgte ein Anstieg der Enzymausscheidung, der von einem Schwellenwert von 0.44 mg Hg/kg ausgehend eine lineare Abhängigkeit von der Hg-Dosis aufwies. Am zweiten Tag wurde ein statistisch signifikanter Effekt bereits nach 0.25 mg Hg/kg beobachtet. Nach Dosen von 0.75 mg Hg/kg oder mehr fand ein Abfall der Enzymaktivität unter die Kontrollwerte statt, der mehr als 4 Tage anhielt. Behandlung mit 2,3-Dimercaptopropansulfonat (DMPS) bewirkte eine Normalisierung der AP-Ausscheidung. Eine Wirkung auf die LAP-Exkretion wurde nur bei baldiger Verabreichung von DMPS beobachtet. Das gleiche gilt für den Effekt von DMPS auf die Hg-induzierte Letalität. Die Nützlichkeit einer LAP-Bestimmung im Urin zur Abschätzung einer Hg-Inkorporation wird diskutiert.
    Notizen: Abstract The effect of intravenous injections of HgCl2 on the renal excretion of alkaline phosphatase (AP) and leucine aminopeptidase (LAP) was investigated in rats. On the first day after Hg enzyme excretion showed a linear rise with the Hg dose from a threshold value of 0.44 mg Hg/kg. On the second day a statistically significant effect was seen already after 0.25 mg Hg/kg. After doses of 0.75 mg/kg or more a decrease of enzyme activity below control values occurred which persisted for more than 4 days. Treatment with 2,3-dimercaptopropansulfonate (DMPS) brought about a normalization of AP excretion. An effect on LAP excretion was observed only with early treatment. The same holds for the effect of DMPS on Hg-induced lethality. The usefulness of a measurement of LAP excretion for estimating the exposure to inorganic mercury is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00355490
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  • 64
    Digitale Medien
    Digitale Medien
    Neurobehavioral and systemic effects of longterm blood lead-elevation in rats (1977)
    Springer
    Archives of toxicology 37 (1977), S. 247-263 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Lead in blood ; Longterm exposure ; Learning deficit ; Overreaction ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur Erfassung neuropsychologischer Störungen nach ontogenetisch früher Bleiexposition wurde bei männlichen Wistar-Ratten pränatal über deren Mütter, neonatal über die Muttermilch und postnatal über Bleiazetathaltiges Futter (745 mg Pb/kg Futter) chronisch ein erhöhter Blutbleispiegel (PbB) eingestellt. In der Trächtigkeits-und Säugezeit stieg der PbB-Spiegel der Mütter von 24.2 auf 31.2 μg-% an, während derjenige der Nachkommen im Alter von ca. 16 Tagen 26.6 μg-% und im Alter von ca. 190 Tagen 28.5 μg-% betrug. PbB altersgleicher Kontrollen war stets 〈 6 μg-%. Im Alter zwischen 100 und 200 Tagen wurden 20 Bleitiere und 20 Kontrollen blind verschiedenen Verhaltensprüfungen unterzogen, und zwar einem Open Field-Test und einer visuellen Unterscheidungs-Lernaufgabe. Zwei Lernprobleme unterschiedlicher Schwierigkeit, Richtungs- und Größenunterscheidung, wurden benutzt. Im Open Field-Test waren die Bleitiere im Vergleich mit den Kontrollen signifikant unruhiger: Lokomotorische Aktivität, Aufrichten und Putzverhalten waren gesteigert. Die schwierige Größenunterscheidung erlernten nur die Kontrollen, während das leichte Problem, nämlich die Richtungsunterscheidung, von Kontroll- und Bleitieren gleich schnell erlernt wurde. Die beobachteten Bleiwirkungen, gesteigerte motorische Unruhe und Lernleistungshemmung, lassen sich als Indikatoren einer funktionellen Hirnschädigung deuten. Sie legen den Schluß nahe, daß die „Wirkschwelle” für neuropsychologische Störungen nach ontogenetisch frühzeitiger Bleieinwirkung bei der Ratte als unterhalb 35 μg/100 ml liegend angenommen werden muß.
    Notizen: Abstract In order to assess neurobehavioral deficit subsequent to early low-level lead-exposure, Wistar-rats were prenatally Pb-exposed via their mothers, neonatally via their dams' milk, and later on via their diet containing lead acetate (745 mg Pb/kg diet). Blood-lead levels (PbB) of dams increased from 24.2–31.2 μg-% during pregnancy and suckling-periods, those of offsprings were 26.6 μg-% at about 16 days of age and 28.5 μg-% at about 190 days of age. Between 100 and 200 days of age 40 male offsprings were subjected to behavioral testing, namely an open field-test and a visual discrimination-learning task. Two learning-tasks of different complexity, i.e. orientation-and size-discrimination, were used. Data of 20 lead-treated animals were compared with those of 20 age-matched controls. In the open-field test lead-fed animals were significantly more restless than controls; an increase of ambulation, rearing and grooming was observed. In the difficult learning-task, i.e. size discrimination, only the controls did learn the problem, whereas only one of the lead-group did; there was, however, no difference between lead-and control-animals for the easy task, i.e. orientation-discrimination. The observed effects, namely overreaction in the open field and a deficit of visual discrimination learning, may be interpreted in terms of lead-induced CNS-dysfunction. They clearly suggest that the “no-response level” for neurobehavioral damage in the rat, subsequent to early lead-exposure, must be assumed to be lower than 35 μg/100ml.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00330817
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  • 65
    Digitale Medien
    Digitale Medien
    Intracellular histidine content of various tissues (brain, striated muscle and liver) in experimental chronic renal failure (1977)
    Springer
    Journal of molecular medicine 55 (1977), S. 583-585 
    Details
    ISSN: 1432-1440
    Schlagwort(e): Histidin ; Gehirn ; Skelettmuskel ; Leber ; Urämie ; Ratte ; Histidine ; Brain ; Striated muscle ; Liver ; Uremia ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Intracellular histidine levels were determined in brain, striated muscle and liver of rats with chronic renal insufficiency (5/6-nephrectomy) and compared both with normal rats and food-restricted (pair-fed) animals. There was no difference in plasma histidine concentration of the three groups whereas in the brain of the uremic rats histidine was significantly increased. Since there existed no alteration of the cerebral histidine in the corresponding pair-fed group, the finding of a raised histidine level in the renal insufficient rats seems to be due to a specific uremic disorder caused by a cerebral disturbance in histidine metabolism.
    Notizen: Zusammenfassung Bei chronisch niereninsuffizienten Ratten (5/6-Nephrektomie) wurden die intrazellulären Histidin-Konzentrationen verschiedener Organe (Gehirn, Skelettmuskel und Leber) bestimmt. Als Vergleichsgruppen dienten gesunde Kontroll-Ratten sowie sog. „pair-fed“ Ratten, die entsprechend den niereninsuffizienten Tieren eine verminderte Nahrungsmenge zu sich nahmen. Während sich in den untersuchten Gruppen die Plasma-Histidin-Konzentration nicht unterschied, war Histidin im Gehirn der chronisch niereninsuffizienten Tiere signifikant erhöht. Dieser Konzentrations-Anstieg dürfte als urämie-spezifisch anzusehen sein, da die entsprechend minderernährten Kontrolltiere keine Alteration zeigten. Als Ursache ist in erster Linie eine cerebrale Störung des Histidin-Metabolismus zu diskutieren.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01490512
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  • 66
    Digitale Medien
    Digitale Medien
    Enduring effects of morphine pellets revealed by conditioned taste aversion (1977)
    Springer
    Psychopharmacology 51 (1977), S. 279-283 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Morphine ; Naloxone ; Abstinence signs ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphine pellets (75 mg) were implanted subcutaneously in albino rats. Three days later, following 24 h without water, these rats (Group MSN) were given access to a saccharin solution for 30 min, then injected with naloxone hydrochloride. The classical abstinence signs, including “wet dog shakes” and weight loss, were noted in these subjects, but not in controls given placebo pellets and/or saline injections. In addition, when given an opportunity to drink either saccharine solution or water 24 h later, Group MSN rats drank significantly less saccharin than any of the control groups. Similar drinking patterns were found even when naloxone injection was delayed as long as 3 weeks after pellet implantation, when none of the classical abstinence signs were seen and serum levels of morphine and its metabolites were 100 times lower according to radioimmunoassay. This simple and objective technique is thus more sensitive as a measure of prior morphine exposure than any of the commonly used indices. The continued utility of a dependent-nondependent dichotomy is also examined in light of these and other findings.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00431636
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  • 67
    Digitale Medien
    Digitale Medien
    Deficits in passive-avoidance learning following atropine in the developing rat (1977)
    Springer
    Psychopharmacology 54 (1977), S. 139-143 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Atropine ; Cholinergic mechanisms ; Learning ; Ontogeny ; Passive avoidance ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The maturation of cholinergic inhibitory mechanisms that may be involved in passive-avoidance learning was studied in rats 14, 17, 21, 25, 28, and 34 days of age. Acquisition and extinction of the conditioned response were examined under saline and atropine sulfate (5 mg/kg). Learning was also tested following scopolamine hydrobromide injections (1, 4, 8 mg/kg) in rats 17 days of age and following α-methylatropine (5 mg/kg) in 17-and 34-day-old groups. In normal animals the rate of acquisition increased during ontogenesis, with a significant improvement between postnatal days 17 and 21, whereas the rate of extinction did not vary with age. Acquisition was impaired by atropine sulfate at all ages and even totally prevented in younger groups (14 and 17 days of age). It was also completely disrupted by scopolamine in 17-day-old rats. Extinction following acquisition under atropine was more rapid than after normal acquisition. Methyl-atropine was without effect. These results support the hypothesis of central cholinergic mechanisms involved in response suppression, already functioning in the rat 14 days of age and maturing mainly between the 17th and the 21st postnatal days.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00426769
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  • 68
    Digitale Medien
    Digitale Medien
    The effects of psychotropic drugs on exploratory and stereotyped behaviour of rats studied on a hole-board (1977)
    Springer
    Psychopharmacology 55 (1977), S. 67-74 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Rat ; Exploratory behaviour ; Stereotyped behaviour ; Hole-board ; dl-Amphetamine ; Haloperidol ; Apomorphine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Exploratory and stereotyped behaviour of Male Wistar rats was studied on a hole-board. The two forms of behaviour were differentiated according to the pattern of hole-dipping activity. Increasing doses of dl-amphetamine stimulated both forms of behaviour with stereotyped behaviour becoming predominant particularly at the higher dose levels. At the highest dose of amphetamine used (16 mg/kg) a gradual transition from exploratory to stereotyped behaviour was observed with time. As the drug wore off this transition was reversed. Haloperidol at a dosage of 0.1 and 0.05 mg/kg blocked the response to a high dose of amphetamine whereas a lower dose (0.02 mg/kg) blocked the stereotyped response to amphetamine while some exploratory behaviour still took place. Apomorphine inhibited hole-dipping but at lower doses another form of exploratory behaviour was induced, this behaviour becoming stereotyped as the dose was increased. It is concluded that there is a close relationship between exploratory and stereotyped behaviours. Monoamine systems appear to play a significant role in the regulation of both forms of behaviour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00432819
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  • 69
    Digitale Medien
    Digitale Medien
    The effect of chronic ethanol treatment on behaviour and central monoamines in the rat (1977)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 300 (1977), S. 205-216 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Chronic ethanol treatment ; Rat ; Behaviour ; Central monoamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rats weaned at 16 days of age were treated with various ethanol concentrations (8–24% w/v) for 270 days. The effect of the chronic ethanol treatment on the growth rate, the diurnal pattern of drinking, the open field activity, and the conditioned avoidance acquisition and retention of the rats were studied. Termination of the chronic ethanol administration caused two types of withdrawal syndromes. The first, an acute withdrawal syndrome was observed within 12 h after the discontinuation of the ethanol treatment and was characterized by extreme hyperexcitability. The second, a delayed withdrawal syndrome was characterized by a more coordinated behavioural stimulation and developed first after about 3 days after the discontinuation of the ethanol treatment. Biochemically, the latter withdrawal syndrome was accompanied by an increased rate of tyrosine hydroxylation (measured as the accumulation of dopa after inhibition of aromatic amino acid decarboxylase) in the striatum and dopamine-rich limbic structures. No differences in the accumulation of 5-hydroxytryptophan were observed. Furthermore, there was an increased level of dopamine concomitant with a decreased level of noradrenaline in the limbic areas during ongoing ethanol treatment. On the 4th day after withdrawal of ethanol the endogenous levels of dopamine and noradrenaline were statistically significantly reduced in the limbic structures. The data of the present study indicate that chronic ethanol administration induces various kinds of behavioural changes and that these changes at least partially are mediated via central catecholamine mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00500962
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  • 70
    Digitale Medien
    Digitale Medien
    Bone transplantation antigens cellular and humoral immune response studies (1977)
    Springer
    International orthopaedics 1 (1977), S. 5-8 
    Details
    ISSN: 1432-5195
    Schlagwort(e): Bone ; Transplantation ; Antigens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les réactions immunologiques, cellulaires et humorales, ont été étudiées sur des rats consanguins, chez lesquels ont été transplantés, tant de l'os que du tissu cortical, compte non tenu des principales barrières d'histocompatibilité. Les résultats obtenus après culture lymphocytaire et étude de la cytotoxicité sérologique font penser que les antigènes de transplantation se situent à la surface des cellules osseuses.
    Notizen: Summary Cellular and humoral immune responses were studied in inbred rats grafted with complete bone and marrow-free cortical bones transplanted across major histocompatibility barriers. Mixed lymphocyte cultures and serum cytotoxicity results suggest that transplantation antigens are present on bone cells surfaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00269750
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  • 71
    Digitale Medien
    Digitale Medien
    Filaments and rod-shaped tubulated bodies in the endothelia of anterior cerebral arteries in young rats (1977)
    Springer
    Cell & tissue research 182 (1977), S. 505-511 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Endothelium ; Cerebral artery ; Filaments ; Rod-shaped inclusion ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Endothelia of the anterior cerebral arteries in rats aged 1 to 3 days were studied. Thin (about 50–90 Å) and thick (about 100–110 Å) filaments are present in the endothelia. Numerous spherical- or rod-shaped bodies, measuring approximately 0.07 to 0.3 μm in diameter and up to 0.6 μm in length occur in the endothelial cells. These bodies contain a tubular structure. The diameter of the individual tubules is about 200 Å. The present observations suggest that spherical- or rod-shaped inclusions are first synthesized in the rough endoplasmic reticulum and thereafter these materials are transported into the Golgi complex for maturation. A small number of the inclusions, however, may originate directly from the rough endoplasmic reticulum and not pass through the Golgi apparatus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219832
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  • 72
    Digitale Medien
    Digitale Medien
    Transport adenosine triphosphatase activity in the rat cornea (1977)
    Springer
    Cell & tissue research 176 (1977), S. 431-443 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Cornea ; Rat ; NaK-ATPase ; K-NPPase ; Histochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sodium-potassium activated adenosine triphosphatase (NaKATPase) activity of the rat cornea was investigated histochemically using a Pb2+-precipitation technique in which adenosine triphosphate (ATP) is used as substrate and two methods for potassium-dependent para-nitrophenyl-phosphatase (K-NPPase) activity. With all the three techniques used it was demonstrated that the sodium-potassium-activated adenosine triphosphatase (NaK-ATPase) activity is localized in the cell membranes of the endothelium whereas a much weaker activity was observed in the epithelium. When the Pb2+-technique was used, the epithelial cell membranes showed a weaker reaction in the presence of ouabain. This activity was only Mg2+-dependent and was presumably due to an Mg2+-dependent ATPase. The validity of the histochemical techniques for NaK-ATPase activity is discussed. The results emphasize the importance of the endothelium as the main site of Na+ transport in the cornea. Small amounts of the enzyme are also present in the epithelium, which seems to be rich in Mg2+-ATPase. Provided that careful controls are performed, all the methods give consistent results in the cornea.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00231400
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  • 73
    Digitale Medien
    Digitale Medien
    Ultrastructure of the rat pineal gland grafted under the kidney capsule (1977)
    Springer
    Cell & tissue research 176 (1977), S. 131-142 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pineal gland ; Graft ; Ultrastructure ; Innervation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pineal glands were grafted under the kidney capsule of mature male rats for periods of 20, 40, 60 and 100 days. Each grafted gland was then excised and divided into two halves. One half was processed for conventional electron microscopy and the other was fixed in aldehydes and then incubated in a zinc iodide-osmium tetroxide mixture at pH 4.4 (A-ZIO-4.4). During the forty days following the operation pinealocytes showed the typical ultrastructural features associated with cells with a high protein and/or peptide secretory activity. On the other hand, during this period, the number of granular vesicles decreased progressively. From day 40 on, the grafted pinealocytes lacked granular vesicles. During the second half of the experimental period the ultrastructure of the pinealocytes indicated that their secretory activity was considerably decreased. During the acute phase of the experimental period numerous structures regarded as the tip of growing axons as well as typical nerve fibres appeared around blood vessels and within the parenchyma of the grafted gland. In the transplanted tissue obtained 60 and 100 days after the operation the growth cones were scarce, whereas typical nerve endings became numerous. These endings contained small clear vesicles which reacted positively when the tissue was treated with A-ZIO-4.4. The secretory activity of the grafted pineal gland and the nature of the nerve fibres which innervate the graft are discussed. The authors wish to thank Mrs. E.M. Rodríguez de Calderón for her valuable help
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220349
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  • 74
    Digitale Medien
    Digitale Medien
    Further evidence for the existence of intralobular nerves in the rat liver (1977)
    Springer
    Cell & tissue research 177 (1977), S. 287-290 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Liver ; Intralobular nerves ; Rat ; Cobalt and Procion Yellow staining
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In a recent study (Skaaring and Bierring, 1976) we found cholinesterase positive nerve-like structures in the lobules of rat liver, and scanning electron microscopy revealed cords having a distribution pattern similar to that of the cholinesterase-positive structures. To obtain further evidence for an intralobular nerve supply the methods of cobalt and Procion Yellow nerve staining (Stretton and Kravitz, 1968; Iles and Mulloney, 1971; Pitman, Tweedle and Cohen, 1972) were adapted, iontophoretic introduction of the dyes being attempted through cut axonal ends in the surface of small excised blocks of rat liver.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221089
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  • 75
    Digitale Medien
    Digitale Medien
    Regeneration of soleus muscles of rat autografted in toto as studied by electron microscopy (1977)
    Springer
    Cell & tissue research 177 (1977), S. 159-180 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Muscle transplantation ; Rat ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat soleus muscles were autografted from right to left legs, and regeneration following necrosis of all original myofibres was studied after 7 to 250 days. The best regenerates were from grafts replacing all calf muscles and sutured to the tendon stumps. After 30 days the size of such regenerates was equal to those from minced gastrocnemius muscles: the cross sectional area of muscle tissue was 30% (1.7 mm2) and the number of fibres was 180% (4500) of normal soleus muscles; the fibre diameters were 10 to 40 μm. To increase the number of myoblasts before grafting some muscles were injured by Ringer solution of 70° C and transplanted after 2 days. Nevertheless, this did not influence regeneration. After 7 days clusters of myotubes occurred in the periphery of the muscle. These myotubes originated from myoblasts growing like endothelial cells on the inner face of the persisting basal lamina tubes of necrotic fibres. After 30 days the muscles were vascularized. Fibres formed in a common basal lamina detached and so looked “split”. Satellite cells of new fibres came from undifferentiated cells associated with myotubes, i.e. from myoblasts. After 30 days and more regenerates contained three sorts of fibres. 1. Thin (5 to 20 μm) fibres resembling fetal muscle fibres. They were most prominent after 30 days, and probably not yet innervated. 2. Thin (10 μm) degenerating fibres as in long-time denervated muscles. 3. Thick (more than 30 μm) mature looking fibres which were innervated and revealed end-plates. Half of the grafts studied after 30 and 60 days contained unmyelinated and myelinated axons which had grown along strands of surviving Schwann cells. After 250 days, only two muscles were studied which both lacked innervation. Almost all regenerates contained muscle spindles, which, however, were not innervated. Within the persisting spindle capsules new muscle fibres had been formed from satellite cells of the former intrafusal fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221079
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  • 76
    Digitale Medien
    Digitale Medien
    The development of innervation in the rat atrioventricular node (1977)
    Springer
    Cell & tissue research 178 (1977), S. 73-82 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Atrioventricular node ; Rat ; Innervation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The problem of development of the innervation of the rat atrioventricular node has been investigated by electron microscopy. Nerve bundles appear in relation to the node as early as the second postnatal day and vesiculated axons are seen throughout the entire node by the fourth day. Intimate contacts between nodal cells, axons and terminal varicosities are frequently observed. Use of the 5-hydroxydopamine tracer technique has enabled the identification of both cholinergic and adrenergic axons. It is concluded that the node has a dual innervation although cholinergic endings far outnumber those classified as adrenergic on the sixth postnatal day. These results are quite different to earlier findings made at the light microscope level and the discrepancies are discussed with respect to the histochemical techniques used. The suggestion that nodal differentiation is induced by nerves is considered in relation to the differences in cholinesterase activity exhibited by nodal cells during normal development and following neonatal sympathectomy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232825
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  • 77
    Digitale Medien
    Digitale Medien
    Effects on gonadal function by lesioning tanycytes in the median eminence of the rat and Japanese quail (1977)
    Springer
    Cell & tissue research 178 (1977), S. 143-153 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Median eminence ; Tanycytes ; Gonadal function ; Rat ; Japanese quail
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ependymal linings of the median eminence were destroyed by electric cautery or intraventricular injection of picric acid in the rat and Japanese quail. In these animals the ventricular lumen near the median eminence disappeared due to adhesion of lesioned walls on both sides of the third ventricle. Electric lesions of the ependymal layer containing tanycytes did not induce appreciable disturbance in the estrous cycles. Rats in which tanycytes were lesioned by picric acid displayed 4-day estrous cycles after prolonged diestrus (10–22 days). After destruction of tanycytes in the quail, a photostimulated gonadal growth was observed. It is concluded that the tanycyte transport of the ventricular fluid to capillaries of the portal vessels appears unnecessary for maintenance of adenohypophysial gonadotrophic activities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219042
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  • 78
    Digitale Medien
    Digitale Medien
    Effect of glucagon on the secretory process in the rat exocrine pancreas (1977)
    Springer
    Cell & tissue research 182 (1977), S. 193-204 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glucagon ; Exocrine pancreas ; Secretory process ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Glucagon was infused into conscious rats in doses of 10 to 80 μg/h for periods up to 24 h. The effect on the secretory process of the exocrine pancreas was studied in vitro using isolated pancreatic lobules. A pronounced inhibition of the rate of protein synthesis and discharge of stored and newly synthesized proteins combined with increased enzyme content in the pancreas were observed after 30 min infusion. This effect was absent after longer infusion periods of up to six hours. After 12 to 24 h infusions a marked degranulation and decrease in enzyme content was observed. While the rate of protein synthesis was not significantly enhanced, both the basal and stimulated discharge of enzymes from the pancreas were increased. The results suggest a biphasic response of the pancreas to prolonged glucagon infusion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220588
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  • 79
    Digitale Medien
    Digitale Medien
    Ultrastructural studies on the secretory cycle of the neurosecretory cells and the formation of herring bodies in the paraventricular nucleus of the rat (1977)
    Springer
    Cell & tissue research 177 (1977), S. 1-8 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Paraventricular nucleus ; Rat ; Types of neurons ; Secretory cycle ; Herring body
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the neurosecretory cells in the paraventricular nucleus of the normal male rat was studied by electron microscopy during various functional states. Four morphologically distinct types of neurosecretory cells were observed. It appears that they do not represent different classes of cells but different phases of secretory activity of a single cell type. The perikarya of the neurosecretory cells show a definite cycle of formation and transportation of secretory granules. We have designated the phases of this cycle as: (1) phase of synthesis, (2) phase of granule production, (3) phase of granule storage and (4) phase of granule transport. The neurosecretory granules appear to be moved in bulk into the axons, forming a large axonal swelling filled with granules as a result of one cycle in the neurosecretory process. Thus it may be postulated that a secretory cycle in the perikaryon of the neurosecretory cell seems to result in the formation of a Herring body in its axon, and that its content is then conveyed to the posterior pituitary.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221114
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  • 80
    Digitale Medien
    Digitale Medien
    Der Einfluß des duodenogastrischen Refluxes auf das Epithel an der gastroenteralen Anastomose (1977)
    Springer
    Langenbeck's archives of surgery 344 (1977), S. 207-217 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Gastroenterostomy ; Duodenal reflux ; Epithelial lesions ; Nitrosoguanidine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Der Einfluß des chronischen duodenogastrischen Refluxes auf die Magenschleimhaut des nicht resezierten Magens wurde im Hinblick auf die Disposition der gastroenteralen Anastomose für die Krebsentstehung tierexperimentell an männlichen Wistarratten untersucht. Hierzu wurden Tiere mit einer Gastroenterostomie ohne Enteroanastomose und Tiere, bei denen ein Reflux durch eine Y-Gastroenterostomie nach Roux ausgeschlossen war, mit einer zeitlich unterschwelligen Cancerogendosis (Nitrosoguanidin) exponiert. Es wird gezeigt, daß auch unabhängig von der Cancerogenexposition ein chronischer duodenogastrischer Reflux zu adenomartigen Drüsenproliferationen mit z. T. atypischen Epithelregeneraten an der Anastomose führt, die durch eine Gastroenterostomie nach Roux verhindert werden können. Anastomosencarcinome, wie in früheren Untersuchungen am resezierten Magen bei sonst gleichen Versuchsbedingungen beschrieben, konnten nicht induziert werden. Somit spielen für die Krebsentstehung an der gastroenteralen Anastomose neben dem Reflux auch die durch die Magenresektion selbst hervorgerufenen Veränderungen eine nicht unwesentlilche Rolle.
    Notizen: Summary The cancerogenic effect of continous duodenal reflux on the gastric mucosa has been investigated in male Wistar-rats after gastrointestinal anastomosis. Groups of animals with gastroenterostomy without enteroenteral anastomosis and with Roux-en-y-anastomosis preventing duodenal reflux were treated with lower dosages of the cancerogenic Nitrosoguanidine. Proliferative mucosal alterations near the gastroenteral anastomosis were observed. In addition the gastric mucosa was characterized by adenomatous lesions caused by duodenal reflux. The changes detected were not influenced by Nitrosoguanidine and did not appear in cases of Roux-en-y-anastomosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01254075
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  • 81
    Digitale Medien
    Digitale Medien
    Das Krebsrisiko im Resektionsmagen (1977)
    Springer
    Langenbeck's archives of surgery 344 (1977), S. 71-82 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Cancer risk ; Resected stomach ; Rat ; Duodenogastric reflux ; N-methyl-N′-nitro-N-nitrosoguanidine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde die Frage geprüft, ob obligater duodenogastrischer Reflux unter Langzeitbedingungen das Wachstum von Carcinomen oder Sarkomen im resezierten Magen beeinflußt. 72 männliche Wistarratten wurden einer Magenresektion unterworfen. Die erforderliche Gastroenteroanastomose wurde bei 39 Tieren als short loop GE (Billroth II) mit obligatem Reflux von Galle und Duodenalsekret in den Restmagen angelegt. Die restlichen 33 Tiere erhielten eine Y-förmige GE (nach Roux) mit seitlicher Einmündung des Duodenum in den Dünndarm; Reflux von Galle in den resezierten Magen war dadurch unmöglich. Die Carcinominduktion erfolgte durch kontinuierliche Gabe von N-Methyl-N'-Nitro-N-Nitrosoguanidin im Trinkwasser. Bei der Sektion der Tiere mit Reflux 33 Wochen nach Carcinogengabe fand sich die Mehrzahl der malignen Tumore von Magenstumpf, Anastomose (GE) und angrenzendem Dünndarm in der Tiergruppe mit obligatem Reflux (13 von 22). Die Tiergruppe ohne Reflux (Y-Roux GE) wies demgegenüber signifikant weniger Carcinome auf (7 von 21); die Tumorincidenz dieser Gruppe entsprach derjenigen eines nicht operierten Kontrollkollektives (5 von 22). - Die Ergebnisse unserer Untersuchungen zeigen, daß die in der Technik des short loop durchgeführte Gastroenteroanastomose des Billroth 11-Magens das Krebswachstum im Anastomosengebiet in besonders ausgeprägtem Maße fördert. Ausschlaggebend für die gesteigerte Carcinominduktion ist der chronische Reflux von Galle und Duodenalsekret, der bei der short loop-GE obligat über den Magnrest fließt.
    Notizen: Summary The purpose of this study was to find whether the reflux of bile and pancreatic juices following stomach resection (duodenogastric reflux) enhances the incidence of carcinomas near the gastroenteric anastomosis. 72 male Wistar rats were subjected to stomach resection. The gastroenteric anastomosis (GE) was performed either as short loop anastomosis (Billroth II;n = 39), thus providing a continuous duodenogastric reflux, or as Y-shaped GE (according to Roux;n = 33). By the latter technique, bile and pancreatic juices are derived quantitatively into the jejunum without coming into contact with the remaining part of the stomach. During a period of 33 weeks, operated rats as well as intact animals were given the carcinogen N-methyl-N′-nitro-N-nitrosoguanidine (NG; 120 mg/1) in the drinking water. At autopsy, 33 to 36 weeks after daily oral administration of NG, most of the tumours were found in operated rats undergoing continuous ref lux (Billroth II group). In contrast to these findings, the incidence of carcinomas was significantly lower in animals without reflux (Roux group or intact control rats).-The results of our experiments demonstrate that, in rats, the duodenogastric reflux contributes substantially to the development of carcinomas of the resected stomach.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01259380
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  • 82
    Digitale Medien
    Digitale Medien
    Bakterielle Besiedlung und Nitritbildung im Magen nach Gastroenterostomie (1977)
    Springer
    Langenbeck's archives of surgery 344 (1977), S. 109-114 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Gastric carcinoma ; Gastroenterostomy ; Bacterial flora ; Nitrit ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Anlage einer Gastroenterostomie ohne Enteroanastomose führt zu einer Veränderung der bakteriellen Magenbesiedlung, wobei besonders der Anteil nitritspaltender Bakterien erhöht ist. Dies hat ein Ansteigen der Nitrit-Konzentration im Magensaft zur Folge. Die hierdurch mögliche vermehrte Bildung carcinogener Nitrosamine wird im Hinblick auf das Entstehen eines Carcinoms im operierten Magen diskutiert. Da die beschriebenen Veränderungen durch eine Gastroenterostomie nach Roux weitgehend verhindert werden, soll dies bei der Passagewiederherstellung nach Operation am Magen berücksichtigt werden.
    Notizen: Summary A gastroenterostomy without enteroanastomosis leads to a change in the bacterial flora of the stomach, where-by in particular the proportion of nitrite-decomposing bacteria, is enhanced. This results in an increase of nitrite concentration in the gastric fluid, which may possibly be accompanied by an augmented production of carcinogenic nitrosoamine. This latter aspect is considered with respect to the origin of carcinoma in the operated stomach. Since the reported changes will be largely prevented by a Roux-Y-gastroenterostomy, this should be taken into consideration for reconstruction of the alimentary tract after gastric surgery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01259384
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  • 83
    Digitale Medien
    Digitale Medien
    Succinimidbildung bei der Synthese des Insulin-A-Ketten(14-21)-Octapeptids (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1-11 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Formation of Succinimide During the Synthesis of the Insulin A Chain(14-21) OctapeptideDuring the synthesis of insulin A chain (14-21) fragments it was observed that alkaline treatment of Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut and Msc-Tyr-(But)-Gln-Leu-Glu(OBut)Asn-Tyr(But)-Cys(Trt)-Asn-OBut caused quantitative formation of succinimide in position 21.
    Notizen: Bei der Synthese von Teilsequenzen der Insulin-A-Kette (14-21) wurde während der alkalischen Abspaltung der Msc-Gruppe von Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys-(Trt)-Asn-OBut und Msc-Tyr-(But)-Gln-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut in allen Fällen Succinimidbildung in Position 21 beobachtet.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100102
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  • 84
    Digitale Medien
    Digitale Medien
    Carben-Reaktionen, IX. Zur Reaktion von Amidacetalen mit Heterocumulenen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 37-48 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Carbene Reactions, IX. On the Reaction of Amide Acetals with HeterocumulenesDeprotonation of the (dimethylamino)methoxycarbenium ion (10) by NaH liberated the carbene 2, which was trapped by aryl isocyanate to give the hydantoin 6 and by phenyl isothiocyanate to yield 8. Hence, the carbene 2 is assumed to be also an intermediate in the corresponding reactions of the amide acetal 1 which lead to the hydantoins 6 and 8. The reaction of 1 with phenyl isothiocyanate yielded the products 4, 7, 8, or 12 depending on the reaction conditions. An equilibrium between 1 and the carbene 2 is suggested by the reaction of 1 with sulfur to give 16, and is the basis for mechanistic discussions.
    Notizen: Das durch Deprotonierung des (Dimethylamino)methoxy-carbenium-Ions (10) mit NaH freigesetzte Carben 2 addierte sich an-Arylisocyanat zum Hydantoin 6, an Phenylisothiocyanat zu 8. Dies legt nahe, daß auch bei der Umsetzung des Amidacetals 1 mit Heterocumulenen zu den Hydantoinen 6 bzw. 8 das Carben 2 beteiligt ist. Bei der Umsetzung von 1 mit Phenylisothiocyanat entstanden je nach Reaktionsführung die Produkte 4, 7, 8 oder 12. Für deren Bildung werden Mechanismen diskutiert, die von einer Gleichgewichtseinstellung von 1 mit dem Carben 2 ausgehen. Diese Annahme wird durch Umsetzung von 1 mit Schwefel zu 16 gestützt.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100105
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  • 85
    Digitale Medien
    Digitale Medien
    Perhalogenmethylthio-Heterocyclen, VIII. (Perchlorfluormethylthio)- und (Halogenformylthio)-N-Heteroaromaten (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 67-77 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: (Perhalomethylthio)heterocycles, VIII. (Perchlorofluoromethylthio)- and (Haloformylthio)-N-heteroaromaticsPyrrole reacts with Cl3-nFnC—SCl (n = 1-3) to give mixtures of 2- and 3-substituted pyrroles 1 a-c and 2a, b; CF3SCFCl—SCl and XC(O)SCl (X = F, Cl) merely yield 2-substituted derivatives 3. In the presence of excess CF3SCl also disubstituted products 4, 5 are available. Analogously pyrrole derivatives can be substituted directly, dependent on their reactivity (6-14). 1a is oxidized by 3-chloroperbenzoic acid to yield the sulfoxide 15 or the sulfone 16; the reaction with bromine and iodine results in the formation of the fully halogenated compounds 17, 18. Indole reacts with CF3SCl to give the 3-substituted 19, while carbazole yields the N-substituted product 20 in a Grignard reaction. 1H and 19F n. m. r. spectra are discussed.
    Notizen: Pyrrol setzt sich mit Cl3-nFnC—SCl (n = 1-3) zu Isomerengemischen 2- und 3-substituierter Pyrrole 1a-c bzw. 2a, b, um; CF3SCFCl—SCl und XC(O)SCl (X = F, Cl) liefern lediglich 2-substituierte Derivate 3. In Gegenwart eines CF3SCl-Überschusses sind auch disubstituierte Produkte 4, 5 erhältlich. Analog sind Pyrrol-Derivate, je nach ihrer Reaktivität, einer direkten Substitution zugänglich (6-14). 1 a wird durch 3-Chlorperbenzoesäure zum Sulfoxid 15 bzw. Sulfon 16 oxidiert; die Umsetzung mit Brom bzw. Iod führt zu den vollständig halogenierten Verbindungen 17, 18. Indol reagiert mit CF3SCl zum 3-substituierten 19, während Carbazol in einer Grignard-Reaktion das N-Substitutionsprodukt 20 liefert. 1H- und 19F-NMR-Spektren werden diskutiert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100108
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  • 86
    Digitale Medien
    Digitale Medien
    Zur Reaktion des Makosza-Reagens mit Aldehyden und Ketonen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 96-106 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Reactions of Aldehydes and Ketones with the Makosza Dichlorocarbene ReagentPhase transfer-catalyzed reactions of aldehydes and ketones with trichloromethane and 50 per cent aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride (BTEA) at low temperatures result in the formation of α-(trichloromethyl)carbinols 7; in the presence of dimethyl sulfate the corresponding methyl ethers 8 are obtained. At 56 ± 2°C the α-hydroxy-11, α-chloro- 12 and α,β-unsaturated carboxylic acids 13 are formed. In this reaction the α-(trichloromethyl)carbinols 7 can be excluded as intermediates. An alternative reaction mechanism for the formation of 11, 12, and 13 is discussed, which involves direct addition of dichlorocarbene to the C=O double bond to form the dichlorooxiranes 5 followed by rearrangement and saponification.
    Notizen: Aldehyde und Ketone reagieren mit Trichlormethan im Zweiphasensystem mit 50proz. wäßrigem Natriumhydroxid unter Phasentransfer-Katalyse durch Benzyltriethylammonium-chlorid (BTEA) (1) bei tiefer Temperatur zu α-(Trichlormethyl)carbinolen 7, in Gegenwart von Dimethylsulfat zu den entsprechenden Methylethern 8. Bei 56 ± 2°C entstehen α-Hydroxy- 11, α-Chlor- 12 und α,β-ungesättigte Carbonsäuren 13, wobei die α-(Trichlormethyl)carbinole 7 als Zwischen-stufen auszuschließen sind. Als Alternativmechanismus wird die direkte Addition von Dichlor-carben an die C=O-Doppelbindung zu Dichloroxiranen 5 und deren Umlagerung und Verseifung diskutiert.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100111
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  • 87
    Digitale Medien
    Digitale Medien
    Masthead (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100101
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  • 88
    Digitale Medien
    Digitale Medien
    Carben-Reaktionen, VIII. Selektivität nucleophiler Carbene gegenüber Heterocumulenen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 23-36 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Carbene Reactions, VIII. Selectivity of Nucleophilic Carbenes with Regard to HeterocumulenesThe selectivities of N-methylbenzothiazolinylidene (2) and 1,3-diphenylimidazolidinylidene (3) against aryl isocyanates and phenyl isothiocyanate have been determined. The selectivities increase from dimethoxycarbene (1) over 2 to 3. In contrast all three carbenes display equal selectivity with regard to different aryl isocyanates.
    Notizen: Für N-Methylbenzothiazolinyliden (2) und 1,3-Diphenylimidazolidinyliden (3) wurden die Selektivitäten gegenüber verschiedenen Arylisocyanaten einerseits und Phenylisothiocyanat andererseits bestimmt. Diese nehmen vom Dimethoxycarben (1) über 2 zu 3 zu. Dagegen zeigen alle drei Carbene bei 140°C eine übereinstimmende Selektivität gegenüber Arylisocyanaten.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100104
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  • 89
    Digitale Medien
    Digitale Medien
    Untersuchungen an Stoffwechselprodukten von Mikroorganismen, XII. Michigazon, ein neues Phenoxazon aus Streptomyces michiganensis  -  Konstitutionsermittlung und Synthese (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 12-22 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Investigations on Metabolites of Microorganisms, XII. Michigazone, a New Phenoxazone Pigment from Streptomyces michiganensis  -  Structure Determination and SynthesisBy spectroscopic methods and chemical degradation michigazone has been shown to possess structure 7. 7 and some further related phenoxazones have been synthesized by the Kehrmann-method.
    Notizen: Spektroskopische Untersuchungen und chemischer Abbau führten für Michigazon zur Konstitution 7. 7 und einige weitere bisher noch nicht beschriebene Phenoxazone wurden durch Kehrmann-Synthese dargestellt.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100103
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  • 90
    Digitale Medien
    Digitale Medien
    Carben-Reaktionen, X. Ionische Zwischenstufen der Reaktion von Orthoameisensäure-trimethylester mit Arylisocyanat (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 49-52 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Carbene Reactions, X. Ionic Intermediates in the Reaction of Trimethyl Orthoformate with Aryl IsocyanatesThe ion pair 2/3 is assumed to be the crucial intermediate in the reaction of trimethyl orthoformate with aryl isocyanates. The collapse of the ion pair to 4 is a fast subsequent reaction. The acid base reaction of the ion pair to the carbene 6 proceeds with a comparable rate. Methoxyl transfer of 2/3 to form 1 is considerably slower. Transalkylation of the ion pair to 8 has not been observed.
    Notizen: Bei der Umsetzung von Orthoameisensäure-trimethylester mit Phenylisocyanat wird das Ionen-paar 2/3 als zentrale Zwischenstufe angenommen. Eine rasche Folgereaktion dieses Ionenpaares ist die Kombination zu 4. Vergleichbar schnell verläuft die Säure-Basen-Reaktion im Ionenpaar zum Carben 6. Eine Methoxyl-Übertragung aus 2/3 zu 1 ist erheblich langsamer. Die Umalkylierung zu 8 konnte nicht beobachtet werden.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100106
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  • 91
    Digitale Medien
    Digitale Medien
    Aktivierte Ethylene, V. Umsetzung von Aromaten mit Chlormethylenmalonsäure-Derivaten. Eine neue Synthese aromatischer Aldehyde (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 86-95 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Activated Ethylenes, V. Reaction of Aromatic Compounds with Derivatives of Chloromethylenemalonic Acid. A new Synthesis of Aromatic AldehydesThe derivatives of chloromethylenemalonic acid 3 and 4 react with aromatic compounds in the presence of aluminium chloride to give the arylmethylenemalonic acid derivatives 5a-i and 6a-d. By hydrolysis of the C=C double bond the corresponding dinitriles 2a-g are converted into aldehydes.
    Notizen: Chlormethylenmalonsäure-Derivate 3 und 4 lassen sich in Gegenwart von Aluminiumchlorid mit Aromaten umsetzen, wobei die Arylmethylenmalonsäure-Derivate 5a-i und 6a-d entstehen. Die entsprechenden Dinitrile 2a-g lassen sich durch Hydrolyse der C=C-Doppelbindung in Aldehyde überführen.
    Zusätzliches Material: 8 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100110
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  • 92
    Digitale Medien
    Digitale Medien
    Zur Stereochemie der Norcaradien-Norcaradien-Umlagerung, I. Die Synthese optisch aktiver [Norcaradien ⇌ Cycloheptatrien]-Derivate (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 107-123 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Stereochemistry of the Norcaradiene-Norcaradiene Rearrangement, I. The Synthesis of Optically Active [Norcaradiene ⇌ Cycloheptatriene] DerivativesAnion 14 derived from treatment of 1,3,5-cycloheptatriene-7-carbonitrile (13) with n-butyllithium or lithium diisopropyl reacts with methyl iodide, deuterium oxide, and carbon dioxide to give the corresponding 7,7-disubstituted derivatives 2, 13-D, and 16. By a sequence of reactions 2 was transformed into the optically pure [norcaradiene ⇌ cycloheptatriene] systems 4 and 10. The equilibrium concentrations of the [norcaradiene ⇌ cycloheptatriene] systems 2-12 were determined by 1H n.m.r. mesurements at low temperatures.
    Notizen: Das aus 1,3,5-Cycloheptatrien-7-carbonitril (13) mit n-Butyllithium oder Lithium-diisopropylamid erzeugte Anion 14 reagiert mit Methyliodid, Deuteriumoxid und Kohlendioxid ausschließlich zu den entsprechenden 7,7-disubstituierten Derivaten 2, 13-D, und 16. Aus 2 lassen sich durch eine Folge von Reaktionen die optisch reinen [Norcaradien ⇌ Cycloheptatrien]-Systeme 4 und 10 synthetisieren. Mit Hilfe der Tieftemperatur-1H-NMR-Spektroskopie wurden die Gleichgewichtskonzentrationen der [Norcaradien ⇌ Cycloheptatrien]-Systeme 2-12 ermittelt.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100112
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  • 93
    Digitale Medien
    Digitale Medien
    Reaktionen mit 4-Acetoxy-2-cyclopenten-1-on (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 146-153 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Reactions with 4-Acetoxy-2-cyclopenten-1-oneBy using 4-acetoxy-2-cyclopenten-1-one (8) as a synthone for the non-existent cyclopentadienone (5), Michael additions are performed that give rise to trans-disubstituted cyclopentanone derivatives (11,12). In the case of tert-butyl acetoacetate as Michael donator the addition to 11 is followed by an aldol-cyclisation to the trans-perhydroazulene system 22.
    Notizen: Unter Verwendung von 4-Acetoxy-2-cyclopenten-1-on (8) als Synthon für das nicht existenzfähige Cyclopentadienon (5) wurden Michael-Additionen durchgeführt, die zu trans-disubstituierten Cyclopentanon-Derivaten (11, 12) führen. Bei Verwendung von tert-Butyl-acetacetat als Michael-Donator schließt sich an die Addition zu 11 eine Aldolcyclisierung zum trans-Perhydroazulensystem 22 an.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100115
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  • 94
    Digitale Medien
    Digitale Medien
    Reaktionen mit 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen. Abfangreaktionen von Nitril-yliden mit Nitrosobenzol (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 605-610 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Reactions with 3,3-Bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. Trapping Reactions of Nitrile Ylides with NitrosobenzeneTrapping reactions of bis(trifluoromethyl)-substituted nitrile ylides 2, generated by thermolysis of 3,3-bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. 1, with nitrosobenzene yield 5,5-bis-(trifluoromethyl)-Δ3-1,2,4-oxadiazolines 3, 3,3-bis(trifluoromethyl)-Δ4-1,2,4-oxadiazolines 4, and 4,4-bis(trifluoromethyl)-1,4-dihydro-1-quinazolinols 5. The compounds 5 are products of a thermal rearrangement of first formed [3 + 2]-cycloadducts. I. r., 1H n. m. r., 19F n. m. r., and mass spectra of the new compounds are described.
    Notizen: Abfangreaktionen von bis(trifluormethyl)-substituierten Nitril-yliden 2, die durch Thermolyse aus 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen 1 erzeugt werden, mit Nitrosobenzol liefern 5,5-Bis(trifluormethyl)-Δ3-1,2,4-oxadiazoline 3, 3,3-Bis(trifluormethyl)-Δ4-1,2,4-oxadiazoline 4 und 4,4-Bis(trifluormethyl)-1,4-dihydro-1-chinazolinole 5. Die Verbindungen 5 sind das Resultat einer thermisch ausgelösten Umlagerung primär erhaltener [3 + 2]-Cycloaddukte. IR-, 1H-NMR-, 19F-NMR- und Massenspektren der neuen Verbindungen werden beschrieben.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100221
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  • 95
    Digitale Medien
    Digitale Medien
    Zur Konjugation in makrocyclischen Bindungssystemen, XXIV. Benzo[12]annulene: Über den Annulen-Charakter von Dibenzo-und Tribenzo[12]annulenen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 619-630 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Conjugation in Macrocyclic Systems, XXIV. Benzo[12]annulenes: On the Annulene Character of Dibenzo- and Tribenzo[12]annulenesAs a contribution to the controversial discussion about the antiaromaticity of the [12]annulene system in the di- and tribenzo[12]annulenes 3 and 4 the compounds 5, 8, and 18 were prepared for comparison. The discussion of the 1H n. m. r. spectra with consideration of the anisotropy effect of the triple bonds led to the conclusion that in contrast to earlier assumptions the [12]annulene system in 3 and 4 in spite of the benzo-anellation is paratropic.
    Notizen: Als Beitrag zu der kontroversen Diskussion über die Antiaromatizität des [12]Annulen-Systems in den Di- und Tribenzo[12]annulenen 3 und 4 wurden die Vergleichsverbindungen 5, 8 und 18 dargestellt. Die Diskussion der 1H-NMR-Spektren unter Berücksichtigung des Anisotropieeffektes der Dreifachbindungen ergab, daß entgegen früherer Auffassung das [12]Annulen-System in 3 und 4 trotz der Benzo-Anellierung paratrop ist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100223
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  • 96
    Digitale Medien
    Digitale Medien
    Zur Konjugation in makrocyclischen Bindungssystemen, XXV. Benzo[12]annulene: Synthese und Eigenschaften eines Benzo-naphtho[12]annulens (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 631-637 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Conjugation in Macrocyclic Systems, XXV. Benzo[12]annulenes: Synthesis and Properties of a Benzo-naphtho[12]annuleneThe benzo-naphtho[12]annulene 4, where in contrast to 1, 2, and 3 a planar twelve-membered ring is present, has been synthesized via 6-9. 1H n. m. r. absorption of the internal hydrogen is observed at δ = 13.13 ppm. The allotment of this considerable down-field shift to the paratropic effect of the annulene system and the anisotropy of the triple bonds is discussed. For this purpose, the twelve-ring system 5 in which the macrocyclic conjugation is interrupted has been synthesized from 9 via 10 and 11.
    Notizen: Das Benzo-naphtho[12]annulen 4, bei dem im Gegensatz zu den Verbindungen 1, 2 und 3 eine ebene Zwölfring-Struktur fixiert ist, wurde über 6-9 synthetisiert. Die 1H-NMR-Absorption des inneren Wasserstoffatoms wird bei δ = 13.13 ppm beobachtet. Die Aufteilung dieser beträchtlichen Tieffeld-Verschiebung in den Paratropie-Effekt des Annulen-Systems und den Anisotropie-Effekt der Dreifachbindungen wird diskutiert. Hierzu wurde das Zwölfring-System 5, bei dem die makrocyclische Konjugation unterbrochen ist, von 9 über 10 und 11 synthetisiert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100224
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  • 97
    Digitale Medien
    Digitale Medien
    1,3-Anionische Cycloadditionen, XV. Reaktionen von trans,trans-1,3-Diphenyl-2-azaallyllithium mit Heterokumulenen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 651-655 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: 1,3-Anionic Cycloadditions, XV. Reactions of trans,trans-1,3-Diphenyl-2-azaallyllithium with Heterocumulenestrans,trans-1,3-Diphenyl-2-azaallyllithium (1) reacts with phenylisocyanate, phenylisothiocyanate, and methylisothiocyanate to give an imidazolidine-4-one (2a) or imidazolidine-4-thione (2b, c), respectively. When reacting with carbon disulfide or dicyclohexylcarbodiimide (symmetrical heterocumulenes) the cycloaddition is followed by a fast secondary reaction (→ 4, 7).
    Notizen: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich regiospezifisch an die CN-Doppel-bindung des Phenylisocyanats sowie Phenyl- und Methylisothiocyanats unter Bildung eines Imidazolidin-4-ons (2a) bzw. -4-thions (2b, c). Bei entsprechenden Umsetzungen mit den symmetrischen Heterokumulenen Schwefelkohlenstoff und Dicyclohexylcarbodiimid folgt der Cycloaddition jeweils eine schnelle Sekundärreaktion (→4, 7).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100227
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  • 98
    Digitale Medien
    Digitale Medien
    Reaktionen von trans-[Pt(CO2R)(CO)(PPh3)2] +BF4- mit Alkinen: Bildung von Alkinyl- und Alkenylplatin(II)-Komplexen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 667-676 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Reactions of trans-[Pt(CO2R)(CO)(PPh3)2]+BF4- with Alkynes: Formation of Alkynyl- and Alkenylplatinum(II) ComplexesThe alkoxycarbonyl complexes [Pt(CO2R)(CO)(PPh3)2]+ BF4- 1 react with alkynes HC≡CR to give the acetylides 2a-c. On the other hand, cationic β-methoxyvinyl 3 or β-hydroxyvinyl complexes 4, respectively, are obtained from the reactions of 1 with disubstituted acetylenes R1C≡CR2 under participation of the nucleophiles methanol and water. Compounds 3 and 4 are converted into neutral derivatives (5, 6, 8) by methoxide or azide ions. The synthesis of Ir(CO2CH3)(CO)(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 is described. Bonding is discussed for the new complexes by means of n. m. r. and i. r. data.
    Notizen: Die Alkoxycarbonyl-Komplexe [Pt(CO2R)(CO)(PPh3)2]+BF4- 1 setzen sich mit Alkinen HC ≡ CR zu den Acetyliden 2a-c um. Dagegen entstehen aus 1 und disubstituierten Acetylenen R1C≡CR2 unter Beteiligung der Nucleophile Methanol und Wasser kationische β-Methoxyvinyl- 3, bzw. β-Hydroxyvinyl-Komplexe 4. Die Verbindungen 3 und 4 werden mit Methylat- oder Azid-Ionen in neutrale Derivate (5, 6, 8) umgewandelt. Ferner wird die Synthese von Ir(CO2CH3)(CO)-(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 beschrieben. Die Bindungsverhältnisse werden mit Hilfe von NMR- und IR-Daten diskutiert.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100229
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  • 99
    Digitale Medien
    Digitale Medien
    Zweifach überbrückte 5,6-Diamino-4,7-dialkyl-1,3-benzodioxole als Zwischenprodukte zur Synthese von Molekülen mit Knotenstruktur (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 703-716 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Double Bridged 5,6-Diamino-4,7-dialkyl-1,3-benzodioxoles as Intermediates for the Synthesis of Molecules with Knot StructureIn a reaction sequence involving metalation with butyllithium followed by alkylation. cyclohexanone pyrocatechol acetal 4 is converted to the 3,6-dialkylpyrocatechol 11. By subsequent acetalisation with 1,25-dichloro-13-pentacosanone (14), followed by nitration (19), reduction (20), acylation (26), renewed reduction (27), and cyclization, the double bridged benzodioxole 28 is obtained. The compound represents an intermediate in the projected synthesis of a molecule with knot structure.
    Notizen: Ausgehend vom Cyclohexanon-brenzcatechinacetal 4 wird durch Metallierung mit Butyllithium und nachfolgende Alkylierung in einer mehrstufigen Reaktionsfolge das 3,6-Dialkylbrenzcatechin 11 synthetisiert. Durch nachfolgende Acetalisierung mit 1,25-Dichlor-13-pentacosanon (14), gefolgt von Nitrierung (19), Reduktion (20), Acylierung (26), erneuter Reduktion (27) und Cyclisierung wird das zweifach überbrückte Benzodioxol 28 erhalten. Es stellt ein Zwischenprodukt in der geplanten Synthese eines Moleküls mit Knotenstruktur dar.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100233
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  • 100
    Digitale Medien
    Digitale Medien
    Gezielte Synthese von Sulfinato-O- und -S-Komplexen einiger Übergangsmetalle, XIV. Sulfinato-O,S-Komplexe von Palladium(II) und Rhodium(III) (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notizen: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19771100208
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