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  • Chemistry  (27,165)
  • Aerodynamics
  • Fluid Mechanics and Thermodynamics
  • Light microscopy
  • 1970-1974  (27,216)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 10 (1972), S. 82-90 
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Precipitation ; Kinetics ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La cinétique de la formation et de la transformation des précipités de phosphate de calcium, obtenus en mélangeant de volumes égaux de solutions à 6×10−3 M de calcium total et/ou phosphate total est étudiée à 25°C. Les solutions de phosphate sont préajustées à un pH de 7.4. Les changements de pH et de turbidité des solutions sont suivis simultanément en fonction du temps. Les précipités sont isolés à des intervalles de temps variables et caractérisés par diverses méthodes physico-chimiques. Initialement un précipité avec un rapport molaire Ca/P de 1.5, amorphe aux rayons X et en diffraction électronique, est formé. Le spectre IR indique la présence de PO 4 3− et de HPO 4 2− . Après une période métastable, on observe la précipitation d'un matériel cristallin dans ou sur la phase amorphe. Vingt quatre heures après préparation de l'échantillon les précipités présentent surtout les caractères du phosphate octocalcique.
    Abstract: Zusammenfassung Die Kinetik der Bildung und Transformation von Calciumphosphat-Niederschlägen wurde bei 25°C untersucht. Es wurden dazu gleiche Volumen von Lösungen gemischt, bei einer Konzentration von 6×10−3M totales Calcium und/oder totales Phosphat. Die Phosphatlösungen wurden zuerst auf pH 7,4 eingestellt. Veränderungen des pH und Trübung der Lösungen wurden gleichzeitig als eine Funktion der Zeit aufgezeichnet. Niederschläge wurden in verschiedenen Zeitintervallen isoliert und mit verschiedenen physiko-chemischen Methoden charakterisiert. Am Anfang wurde ein Niederschlag mit einem molaren Ca/P-Verhältnis von 1,5, im Röntgenbild und in der Elektronendiffraktion amorph, gebildet. Infrarotspektren deuteten die Anwesenheit von PO 4 3− - und HPO 4 2− -Ionen an. Nach einer metastabilen Periode erfolgte ein Niederschlag aus kristallinem Material innerhalb oder auf der amorphen Substanz. 24 Std nach der Herstellung der Proben zeigten die Niederschläge in der Hauptsache die Charakteristiken von Octocalciumphosphat.
    Notes: Abstract The kinetics of the formation and transformation of calcium phosphate precipitates obtained by mixing equal volumes of solutions, 6×10−3 M in total calcium and/or total phosphate was investigated at 25°. The phosphate solutions were preadjusted to pH 7.4. Changes of the pH and turbidity of the solutions were followed simultaneously as a function of time. Precipitates were isolated at various time intervals and characterized by different physicochemical methods. Initially a precipitate with a molar Ca/P ratio of 1.5, amorphous to X-ray and electron diffraction was formed. IR spectra indicated the presence of PO 4 3− and HPO 4 2− ions. After a period of metastability, precipitation of a crystalline material within or upon the amorphous matter occurred. Twenty four hours after sample preparation the precipitates showed mainly the characteristics of octacalcium phosphate.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 16 (1974), S. 145-152 
    ISSN: 1432-0827
    Keywords: EHDP ; Bone ; Chemistry ; Serum ; Rabbits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The effects of disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) on bone and serum chemistry were investigated in adult rabbits. EHDP was administered by subcutaneous injection at doses of 0.25, 2.5 and 10 mg/kg body weight/day for of 28 days. Blood samples were obtained weekly from each rabbit and serum levels of total calcium, ionized calcium, inorganic phosphate and alkaline phosphatase were determined. At the end of the treatment period all rabbits were sacrificed and the tibiae removed for chemical analysis and histological evaluation. The effect of EHDP administration on serum chemistry was both dose- and time-related. The highest of the three doses, 10 mg/kg/day, resulted in a time-related decrease in total serum calcium. This dose also caused a rapid but transient reduction in serum ionized calcium. The effect of EHDP on serum inorganic phosphate was biphasic. Administration of 2.5 mg/kg/day resulted in a time-related elevation in this parameter, whereas the 10 mg/kg/day dose resulted in a time-related hypophosphatemic response. There were no significant drug-related changes in tibial fat-free dry weight, ash weight, total calcium or total phosphorus values. However, administration of 2.5 and 10 mg/kg/day EHDP resulted in increased osteoid tissue as measured histologically. These results are compared with data from other EHDP studies, and discussed in relation to the maturity and growth-state of the experimental animals.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 14 (1974), S. 3-14 
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Mineral ; Phase ; Chemistry ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des diagrammes de phase d'équilibre ont été déterminés pour le système CaO-P2O5-H2O en utilisant des techniques de synthèse hydrothermique au cours de variatio nsde température allant de 300–600° et 2 Kb H2O de pression. De l'hydroxyapatite bien cristallisé a été synthétisé et caractérisé. De faibles variations de paramètres de la maille cristalline, liées à la température de synthèse et composition globale du matériel initial, ont été déterminées. Des conditions chimiques précises sont nécessaires pour obtenir de l'apatite, en tant que seule phase solide en équilibre dans la solution. Les résultats de diagramme de phase d'équilibre sont comparés avec ceux obtenus dans des milieux synthétiques.
    Abstract: Zusammenfassung Es wurden Gleichgewichts-Phasendiagramme für das System CaO-P2O5-H2O bestimmt, indem hydrothermale Synthese-Techniken im Temperaturbereich von 300–600° und bei einem Druck von 2 Kb H2O verwendet wurden. Es wurde gut-kristallisiertes Hydroxyapatit erzeugt und charakterisiert. Es wurden geringe Unterschiede in den Parametern der Zelleinheiten festgestellt, welche von der angewandten Temperatur und der Zusammensetzung des Startmaterials abhingen. Es waren genaue chemische Bedingungen nötig, um Apatit als die einzige feste Phase im Gleichgewicht mit der Lösung zu erhalten. Die Resultate der Gleichgewichts-Phasendiagramme werden mit früheren Untersuchungen mit der Synthesetechnik verglichen.
    Notes: Abstract Equilibrium phase diagrams have been determined for the system CaO-P2O5-H2 using hydrothermal synthesis techniques in the temperature range 300–600° and 2 Kb H2O pressure. Well-crystallized hydroxyapatite has been produced and characterized. Small variations in unit cell parameters dependent on temperature of synthesis and bulk composition of the starting materials have been determined. Precise chemical conditions were required to obtain apatite as the only solid phase in equilibrium with solution. Equilibrium phase diagram results are compared with previous synthetic investigations.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 7 (1971), S. 150-162 
    ISSN: 1432-0827
    Keywords: Uranium ; Bone ; Distribution ; Fission ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une concentration moyenne de 2.4×10−8 g U/g de cendre a été obtenue à partir de l'os humain normal. La microdistribution de l'uranium dans l'os indique que cet élément est surtout limité à surface de l'endoste et, en particulier, aux surfaces de l'os lamellaire et aux parois des canaux de Havers, ouverts dans l'os corticol. Cette répartition suggère que l'uranium se présente sous une forme chimique impropre à son incorporation dans l'apatite osseux: il ne semble donc pas exister une distribution diffuse significative de l'uranium dans l'os.
    Abstract: Zusammenfassung Eine mittlere Konzentration von 2,4×10−8 g Uran/g Asche wurde in normalen menschlichen Knochen gefunden. Die Feinverteilung von Uran im Knochen zeigt, daß dieses Element hauptsächlich an der endostalen Oberfläche vorkommt, insbesondere an der Oberfläche des trabeculären Knochens und an den Wänden der offenen Haversschen Kanäle im kortikalen Knochen. Diese Verteilung läßt vermuten, daß Uran in einer chemischen Form vorliegt, welche sich für den Einbau in das Knochenapatit nicht eignet. Daraus folgt, daß keine signifikante diffuse Verteilung des Urans innerhalb des Knochens vorliegt.
    Notes: Abstract A mean concentration of 2.4×10−8 g U/g ash has been obtained for normal human bone The microdistribution of uranium in bone indicates that this element is mainly restricted to endosteal surfaces; in particular the surfaces of trabecular bone and the walls of open Haversian canals in cortical bone. This distribution suggests that uranium is present in a chemical form that is not acceptable for incorporation into bone apatite and consequently there does not appear to be a significant diffuse distribution of uranium throughout bone.
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  • 5
    ISSN: 1432-0827
    Keywords: Morphology ; Glycosaminoglycans ; Cartilage ; Chemistry ; Audioradiography ; Healing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une perte de substance ostéo-cartilagineuse, de taille limitée et identique, est réalisée chez le lapin adulte et la cicatrisation est étudiée histologiquement et par autoradiographie après marquagein vitro au35S-sulfate. Une analyse microchimique est pratiquée pour le contenu et la composition en glycosaminoglycanes. 1. Entre la première semaine et la 4ème et 8ème semaine, un tissu conjonctif non-métachromatique se différencie en un cartilage métachromatique et la quantité de sulfate de chondroitine augmente de façon significative aux dépens des glycoprotéines. 2. Jusqu'à la 4ème semaine, la perte de substance est surtout comblée par de l'os néoformé: après cette période, la région est comblée au delà de la limite de la surface articulaire. 3. Le cartilage hyalin, ressemblant morphologiquement, autoradiographiquement et chimiquement au cartilage articulaire, en ce qui concerne la distribution en glycosaminoglycanes, constitute la surface articulaire de la perte de substance comblée dans un tiers des cas après 8 semaines. Le cartilage hyalin s'observe surtout dans les régions où de l'os néoformé a comblé la cavité médullaire. 4. Dans les deux tiers des cas, après 8 semaines, les surfaces articulaires des zones comblées comportent, non seulement du cartilage, mais aussi du tissu fibreux se formant essentiellement sur les parties latérales et dans les régions, où la cavité médullaire, fliant face, à la surface articulaire, n'a pas été comblée par du tissue osseux. La fraction glycoprotéique augmente par rapport à la fraction chondroitine sulfate. 5. Dans la majorité des cas, après 20 semaines, le cartilage néoformé subit des phénomènes dégénératifs, qui se traduisent par une diminution en chondroitine sulfate.
    Abstract: Zusammenfassung Bei ausgewachsenen Kaninchen wurde ein begrenzter, standardisierter, osteochondraler Defekt hervorgerufen, und das regenerierte Gewebe wurde histologisch und autoradiographisch durch Markierung in vitro mit35S-Sulfat und durch mikrochemische Bestimmung des Gehaltes und der Zusammensetzung der Glykosaminglykane untersucht. Die wichtigsten Befunde waren: 1. Zwischen 1 und 4–8 Wochen veränderte sich nichtmetachromatisches Bindegewebe zu metachromatisch gefärbtem Knorpel, und der Anteil an Chondroitin-Sulfat nahm auf Kosten der Glykoproteine signifikant zu. 2. Bis zu 4 Wochen war der Hauptteil des defekten Gebietes mit neugebildetem Knochen gefüllt; nach dieser Zeit lag dieser Bezirk oberhalb der Verknöcherungsgrenze in Richtung der Gelenkoberfläche. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 4. Nach 8 Wochen bestanden Teile der Gelenkoberfläche des Defektes in zwei Dritteln der Fälle nicht nur aus Knorpel, sondern auch aus fibrösem Gewebe, welches vor allem in den seitlichen Teilen des Defektes und an Stellen vorlag, wo die Markhöhle gegenüber der Gelenkoberfläche nicht mit Knochengewebe verschlossen worden war. Die Glykoproteinfraktion nahm im Vergleich zur Chondroitin-Sulfatfraktion zu. 5. Nach 20 Wochen zeigten sich in den meisten Fällen bei neugebildetem Knorpel degenerative Veränderungen, welche durch eine gewisse Abnahme des Chondroitin-Sulfats wiedergegeben wurden.
    Notes: Abstract A limited, standardized osteochondral defect was created in adult rabbits and the regenerated tissue was examined histologically and autoradiographically after labellingin vitro with35S-sulphate, and microchemically for its content and composition of glycosaminoglycans. The principal findings were: 1. Between 1 week and 4 to 8 weeks, non-metachromatic connective tissue differentiated to metachromatically stained cartilage, and the proportion of the chondroitin sulphate increased significantly at the expense of the glycoproteins. 2. Up to 4 weeks, the major part of the defect area was filled with newly formed bone; after this time, the area lay above the level of the “tidemark”, towards the articular surface. 3. Hyaline cartilage with morphological, autoradiographic and chemical resemblance to the articular cartilage in terms of the distribution of glycosaminoglycans constituted the articular surface of the defect area in one-third of the cases at observation times after 8 weeks. Hyaline cartilage was observed mainly in areas where newly formed bone had closed the medullary cavity. 4. In two-thirds of the cases, after 8 weeks, parts of the articular surface of the defect consisted not only of cartilage but also of fibrous tissue, occurring mainly in the lateral parts of the defect and in areas where the medullary cavity facing the articular surface had not been sealed by bone tissue. The glycoprotein fraction increased relative to the chondroitin sulphate fraction. 5. In most cases after 20 weeks, newly-formed cartilage underwent degenerative changes, which were reflected in some reduction of the chondroitin sulphate.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 8 (1971), S. 228-236 
    ISSN: 1432-0827
    Keywords: Skin ; Calcinosis ; Keratin ; Chemistry ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des études histologiques antérieures ont montré que le follicle pileux est particulièrement susceptible de se calcifier, lorsque la peau de rats hypercalcémiques est lésée. Des analyses chimiques et par diffraction aux rayons X du follicule ont confirmé ce résultat. — En se basant sur l'augmentation du calcium et du phosphore, les calcifications débutent dans le tissue folliculaire 6–12 h après une blessure d'intensité moyenne de la peau de rats, ayant reçu du dihydrotachysterol (DHT), et 24–48 h après une blessure similaire chez des rats non injectés. Les diagrammes de diffraction aux rayons X sont diffus. Trois heures après la blessure, on note une augmentation du calcium du tissu folliculaire qui ne semble pas en rapport avec le DHT qui traduit probablement une liaison de calcium plutôt qu'un dépot minéral.
    Abstract: Zusammenfassung Frühere histologische Untersuchungen haben gezeigt, daß der Haarfollikel besonders anfällig für Verkalkungen ist, wenn die Haut von hypercalcämischen Ratten verletzt wird. Dieses Resultat wurde nun durch direkte chemische Bestimmungen und Röntgendiffraktions-analysen von Follikelgewebe bestätigt. Aufgrund der erhöhten Calcium- und Phosphatwerte kann gesagt werden, daß nach einer leichten Quetschung der Haut von Ratten, die mit Dihydrotachysterol (DHT) behandelt wurden, im Haarfollikelgewebe nach 6–12 Std Mineral-ablagerungen stattfanden, wogegen Kontrollratten mit der gleichen leichten Hautverletzung diese Ablagerungen erst nach 24–48 Std zeigten. Röntgendiffraktionsanalysen ergaben ein diffuses Apatit-Muster. Innerhalb 3 Std nach der Verletzung wurde ein Anstieg des Calcium-gehaltes im Follikelgewebe beobachtet, der nicht im Zusammenhang mit der DHT-Behandlung stand, also nicht eine Mineralablagerung, sondern eher eine Bindung von Calcium widerspiegelte.
    Notes: Abstract Previous histological investigations have shown that the hair follicle is particularly susceptible to mineralization when the skin of hypercalcaemic rats is injured. Direct chemical and X-ray diffraction analyses of follicle tissue have now confirmed this finding. As judged by increases in both calcium and phosphorus, mineral deposits began to form in hair follicle tissue 6–12 h after a mild crush injury to the skin of rats dosed with dihydrotachysterol (DHT), and 24–48 h after a similar injury to the skin of non-dosed rats. X-ray diffraction gave a diffuse apatite pattern. Within 3 h of injury there was a rise in the calcium content of follicle tissue which was not related to DHT-dosing and which was probably a reflection of calcium binding rather than mineral deposition.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 8 (1971), S. 304-319 
    ISSN: 1432-0827
    Keywords: Chemistry ; Calcium ; Phosphate ; Solubility ; Computer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un programme d'ordinateur a été mis au point pour calculer les activités ioniques du calcium et l'orthophosphate dans un grand nombre de solutions. Dans le cas de solutions synthétiques, les calculs sont vérifiés en comparant les valeurs de pH, obtenues par ordinateur, avec celles observées expérimentalement. Des essais de ce type, avec des solutions possèdant des concentrations de calcium et d'orthophosphate trouvées dans les liquides biologiques et à des valeurs de pH variant de 3.00 à 10.00, indiquent que le programme est adapté pour des applications biologiques. Le programme n'est pas effectif pour des solutions, dans les lesquelles l'ion bromure est la source principale de la force ionique, sans doute, par manque d'équation étendue de Debye-Hückel dans ces circonstances. Aucune formation de complexe de phosphate de sodium n'a été notée à des concentrations biologiques normales.
    Abstract: Zusammenfassung Es wurde ein Computer-Programm ausgearbeitet, um die Ionenaktivitäten von Calcium und Orthophosphat in einer breiten Varietät von Lösungen zu berechnen. Die Berechnungen wurden bei synthetischen Lösungen durch Vergleiche zwischen den auf diese Weise errechneten pH-Werten und den experimentell gefundenen kontrolliert. Diese Art Kontrollen mit Calcium-und Orthophosphatkonzentrationen, wie sie in biologischen Flüssigkeiten gefunden werden, und mit pH-Werten zwischen 3,0 und 10,0 wies darauf hin, daß das Programm für biologische Anwendungen geeignet war. Das Programm konnte nicht benützt werden für solche Lösungen, bei welchen hauptsächlich das Bromidion zur Einstellung der Ionenstärke verwendet wurde, vermutlich weil die erweiterte Debye-Hückel-Gleichung unter diesen Umständen nicht anwendbar ist. Die Bildung eines Natriumphosphat-Komplexes unter normalen biologischen Konzentrationen konnte nicht nachgewiesen werden.
    Notes: Abstract A computer program has been designed to calculate the ionic activities of calcium and orthophosphate in a wide variety of solutions. In the case of synthetic solutions the calculations were checked by comparing the computed pH values with those observed experimentally. Tests of this type with solutions having the concentrations of calcium and orthophosphate found in biological fluids and with pH values ranging from pH 3.0–10.0 indicated that the program was suitable for biological applications. The program was not effective for solutions in which the bromide ion was a principal source of ionic strength probably because of the failure of the extended Debye-Hückel equation under those circumstances. No evidence for the formation of any sodium phosphate complex at normal biological concentrations could be found.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 10 (1972), S. 171-197 
    ISSN: 1432-0827
    Keywords: Amorphous ; Crystalline ; Calcium phosphate ; Chemistry ; Composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des échantillons non lavés de phosphate de calcium amorphe (ACP) contiennent une fraction labile, non remplaçable, riche en phosphate acide avec un rapport Ca/P faible: cette fraction est perdue de façon irréversible au cours du lavage. De l'ACP frais, précipité entre pH 6.6–10.6, varie dans un rapport molaire Ca/P de 1.18 à 1.50 et dans un rapport HPO 4 2− /P total de 33.0% à 10.1%. A pH 7.40, de l'ACP frais a un rapport molaire Ca/P de 1.36±0.02 et contient 22.8 (±2.2)% HPO 4 2− . Les résultats obtenus avec du précipité non lavé ne peuvent s'expliquer par du Ca2+ emprisonné et de l'HPO 4 2− ou du Na+, Cl− et CO 3 2− exogènes. Les phosphates de calcium amorphes constituent une classe de sels ayant des caractères chimiques variables et des propriétés physiques identiques, comparables au verre. Le CaHPO4·xH2O non cristallin peut être un ACP, surtout au cours des phases précoces de formation. A des pH physiologiques, l'ACP se transforme en petits cristaux applatis contenant de fortes quantités de phosphate acide facilement remplaçable. Le fait de laver la couche de surface produit un changement chimique dans les nouveaux cristaux: des cristaux non lavés donnent des diagrammes de diffraction d'apatite peu cristallins, ainsi que des spectres infra-rouges peu nets, intermédiaires entre des apatites et du phosphate octocalcique. Des explications structurales sont proposées et les compositions minérales amorphe/cristalline de l'os et du cartilage sont recalculées.
    Abstract: Zusammenfassung Ungewaschene Proben von amorphem Calciumphosphat (ACP) enthalten eine unersetzliche labile Fraktion, welche reich an saurem Phosphat ist und ein niederes Ca/P-Verhältnis hat und welche während des Waschprozesses unwiderruflich verloren geht. Natives ACP, welches im pH-Bereich 6,6–10,6 ausgefällt wurde, variierte im molaren Ca/P-Verhältnis zwischen 1,18 und 1,50 und in HPO 4 2− /totales P zwischen 33,0 und 10,1%. Bei pH 7,40 hatte natives ACP ein molares Ca/P-Verhältnis von 1,36±0,02 und enthielt 22,8 (±2,2)% HPO 4 2− . Die Werte beim ungewaschenen Niederschlag rühren weder von aus dem Überstand aufgenommenem Ca2+ und HPO2−, noch von außen kommendem Na+, Cl− und CO 3 2− her. Die amorphen Calciumphosphate werden als eine Klasse von Salzen erkannt, welche veränderliche chemische, aber identische glasartige physicochemische Eigenschaften haben. Nicht kristallines CaHPO4·xH2O kann auch ein ACP sein, besonders in den frühen Bildungsstadien. Bei physiologischem pH verwandelt sich ACP in kleine plattenförmige Kristalle, welche große Mengen von leicht ersetzbarem saurem Phosphat enthalten. Das Waschen dieser Oberflächenschicht erzeugte chemische Veränderungen in den resultierenden Kristallen; ungewaschene Kristalle zeigten ein Diffraktionsmuster, das nur schwach demjenigen des kristallinen Aspatites glich, aber ein schlecht aufgelöstes Infrarotspektrum, welches zwischen Apatit und Octocalciumphosphat war. Es werden strukturelle Erklärungen für alle diese Phenomena diskutiert, und revidierte amorph/kristalline Mineralzusammensetzungen von Knochen und Knorpel wurden neu berechnet.
    Notes: Abstract Unwashed samples of amorphous calcium phosphate (ACP) contain an irreplaceable labile fraction, rich in acid phosphate and low in Ca/P ratio, which is irreversibly lost during the washing process. Native ACP precipitated in the pH range 6.6–10.6 varied in Ca/P molar ratio from 1.18 to 1.50 and in HPO 4 2− /total P from 33.0% to 10.1%. At pH 7.40, native ACP had a Ca/P molar ratio of 1.36±0.02 and contained 22.8 (±2.2)% HPO 4 2− . Unwashed precipitate data could not be attributed to either trapped supernatant Ca2+ and HPO 4 2− or extraneous Na+, Cl−, and CO 3 2− . The amorphous calcium phosphates are recognized as a class of salts having variable chemical but identical glass-like, physicochemical properties. Non-crystalline CaHPO4·xH2O may also be an ACP, especially during early formative stages. At physiological pH, ACP transforms to small platy crystals containing large amounts of readily-replaceable acid phosphate. Washing this surface layer produced chemical alterations in the resultant crystals; unwashed crystals had poorly-crystalline apatitic diffraction patterns but exhibited poorly-resolved infrared spectra intermediate between apatite and octacalcium phosphate. Structural explanations for all these phenomena are discussed, and revised bone and cartilage amorphous/crystalline mineral compositions have been re-calculated.
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  • 9
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    Calcified tissue international 8 (1971), S. 197-210 
    ISSN: 1432-0827
    Keywords: Fluorescence ; Calcium ; Collagen ; Chemistry ; Bone ; Dentine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des composants fluorescents de l'os et la dentine sont séparés des hydrolysats alcalins de leur marice sur des colonnes Sephadex C25 CM d'échange cationique. Les concentrations en fluorescence et le spectre d'excitation (λ max 330 nm) et d'émission (λ max 395 nm) sont les mêmes que ceux observés au niveau des matrices intactes et gélatinisées. Les paramètres de fluorescence ne sont pas altérés par hydrolyse. La filtration sur gel à l'aide de colonnes Sephadex G 10 perment de différencier le matériel isolé en deux composants, ayant la même fluorescence et la même absorption UV. La fluorescence est indépendante de pH de 3.5–9.5. Des études de dialyse et de filtration sur gel de matrices gélatinisées indiquent une association étroite du matériel fluorescent avec les chaines polypeptidiques de collagène.
    Abstract: Zusammenfassung Fluorescierende Bestandteile aus Knochen und Dentin wurden in Sephadex C25 CM Kationen-Austauschersäulen von alkalischen Hydrolysaten ihrer Matrices getrennt. Die Fluorescenzintensitäten sowie die Erregungs- (λ max 330 nm) und Emissions- (λ max 395 nm) Spektren waren dieselben wie bei intakten und gelatinisierten Matrices. Die Fluorescenzparameter wurden durch die Hydrolyse nicht verändert. Eine Gelfiltration über Sephadex-G10-Säulen trennte das isolierte Material in 2 Komponenten auf, welche gleiche Fluorescenz- und UV-Absorptionseigenschaften zeigten. Im pH-Bereich zwischen 3,5 und 9,5 war die Fluorescenz unabhängig vom pH. Dialysierversuche sowie Gelfiltrationsexperimente mitden gelatinisierten Matrices zeigten eine starkgefügte Bindung des fluorescierenden Materials mit den Polypeptidketten des Kollagens.
    Notes: Abstract Fluorescent components in bone and dentine were separated from alkaline hydrolysates of their matrices on Sephadex C25 CM cationic exchange columns. The fluorescence levels, and the excitation (λ max 330 nm) and emission (λ max 395 nm) spectra, were the same as those observed in the intact and gelatinised matrices. The fluorescence parameters were unaltered by the hydrolysis procedure. Gel filtration on Sephadex G. 10 columns further resolved the isolated material into two components with the same fluorescence and UV absorption properties. The fluorescence was independent of pH over the range 3.5–9.5. Dialysis and gel filtration studies on the gelatinised matrices indicated a firmly-bonded association of the fluorescent material with the collagen polypeptide chains.
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  • 10
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    Calcified tissue international 12 (1973), S. 125-136 
    ISSN: 1432-0827
    Keywords: Mineralization ; Molt ; Isopod ; Chemistry ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Au cours de la phase inhabituelle de mue d'un isopode d'eau courante,Lirceuts brachyrus, la moitié postérieure de l'exosquelette est éliminée 24 heures avant la moitié antérieure. A ce stade, une reminéralisation se développe dans la partie postérieure alors que la partie antérieure est dans un stade de pré-mue. Le pourcentage de différence en calcium dans les deux moitiés à mi-mue et mue complète est respectivement de 22% (p〈0.01) et 33% (p〈0.01), indiquant une complexation du calcium pendant la mue. La rapidité de la reminéralisation est illustrée par le fait que le contenu minéral total double dans la partie postérieure entre la mi-mue et la mue totale et dans la partie antérieure entre la fin de la mue et un jour après. Le carbonate de calcium, sous forme de calcite, a pu être identifié par diffraction électronique de coupes fines des téguments.
    Abstract: Zusammenfassung Während der ungewöhnlichen Häutungssequenz des Frischwasser-IsopodenLirceus brachyurus (Harger) wird die hintere Hälfte des äußeren Skeletts 24 Std vor der vorderen Hälfte abgestoßen. In der halbgehäuteten Phase erfolgt Remineralisation im hinteren Teil, während der vordere Teil in einem Vorhäutungszustand ist. Der prozentuale Unterschied des Calciums in den zwei Hälften bei Halb- und Vollhäutungszustand ist 22% (p〈0,01) bzw. 33% (p〈0,01), was andeutet, daß Calcium während der Häutung abgesondert wird. Die Geschwindigkeit der Remineralisation erhellt aus der Tatsache, daß sich der Gesamtmineralgehalt im hinteren Teil zwischen Halt- und Vollhäutung, in der vorderen Hälfte jedoch zwischen Endhäutung und einem Tag nach der Häutung verdoppelt. Calciumcarbonat in kristalliner Calcitform wurde mittels Elektronendiffraktion von dünnen Hautschnitten nachgewiesen.
    Notes: Abstract During the unusual molt sequence of the fresh-water isopod,Lirceus brachyrus (Harger), the posterior half of the exoskeleton is shed 24 hours before the anterior half. At the half-molt stage, occurs in the posterior part while the anterior portion is in a pre-molt condition. The percentage difference in calcium in the two halves at half-molt and full-molt is22 (p〈0.01) and33 (p〈0.01) respectively, an indication that calcium is sequestered during The rapidity of remineralization is illustrated by the fact that the total mineral content doubles in the posterior part between half and full molt and in the anterior half between the end of molt and one day after ecdysis. Calcium carbonate in the calcite cystalline form was demonstrated by electron diffraction of thin sections of the integument.
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  • 11
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    Calcified tissue international 13 (1973), S. 259-270 
    ISSN: 1432-0827
    Keywords: Fluorapatite ; Exchange ; Chemistry ; Crystallography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un échantillon minéral provenant de Burgess, Canada s'est révélé être un speciment exceptionnellement pur de fluoroapatite après analyse chimique et cristallographique. La composition globale de cet échantillon est la suivante: $$(Ca^2 )9.98(Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )0.02(PO_4^{3 - } )5.98(HCO_3^ - ,CO_3^{2 - } )0.02(F^ - )2$$ . L'axe cristallographique C est de 6.865 A et l'axe a de 9.374 A. Des expériences d'échanges réalisés à l'aide de45Ca,32P et18F indiquent la présence de gros cristallites de surface spécifique de l'ordre de 1 m2/g. Il apparait que l'interprétation physique des processus d'échange ne nécessite pas l'existence de compartiments séparés, avec chacun son propre facteur cinétique, les échanges semblent être simplement liés à un changement exponentiel dans l'énergie libre de la réaction. Pour la réaction suivante: $$(Ca)_5 (PO_4 )_3 OH solide + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F solide + (OH^ - )$$ , la constante thermodynamique de 101.26 a été calculée, suggérant que le fluorapatite se forme toujours aux dépens de l'hydroxyapatite dans des conditions physiologiques. Cette transformation se continue en abaissant le pH.
    Abstract: Zusammenfassung Eine Mineralprobe aus Burgess, Kanada, erwies sich nach chemischer und kristallographischer Analyse als außergewöhnlich reines Fluorapatit. Die Gesamtzusammensetzung entspricht: $$(Ca^{2 + } )_{9,98} (Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )_{0,02} (PO_4^{3 - } )_{5,98} (HCO_3^ - ,CO_3^{2 - } )_{0,02} (F^ - )_2 $$ . Die kristallographische c-Achse wurde bestimmt und ergab 6,865 Å, und die a-Achse ergab 9,374 Å. Austauschwerte, welche durch Anwendung von45Ca,32P und18F erhalten wurden, deuteten auf große Kristalliten mit einer spezifischen Oberfläche von ca. 1 m2/g. Die Befunde deuten darauf hin, daß für die physikalische Erklärung des Austauschvorganges keine separaten Kompartimente mit eigenen kinetischen Faktoren nötig sind, sondern daß der Austausch mit dem exponentiellen Wechsel in der freien Energie der Reaktion in einfacher Beziehung steht. Für die Reaktion $$(Ca)_5 (PO_4 )_3 OH_{in fester Form} + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F_{in fester Form} + (OH^ - )$$ wurde als thermodynamische Konstante 101,26 errechnet, was darauf deutet, daß unter physiologischen Bedingungen immer Fluorapatit auf Kosten von Hydroxyapatit entsteht. Diese Umwandlung wird erhöht, wenn das pH erniedrigt wird.
    Notes: Abstract A mineral specimen from Burgess, Canada, proved upon chemical and crystallographic analyses to be an exceptionally pure sample of fluorapatite. The over-all composition corresponds to $$(Ca^{2 + } )_{9.98} (Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )_{0.02} (PO_4^{3 - } )_{5.98} (HCO_3^ - ,CO_3^{2 - } )_{0.02} (F^ - )_2 $$ . The crystallographic c-axis was determined to be 6.865 Å, and the a-axis 9.374 A. Exchange data obtained by employing45Ca,32P, and18F indicate the presence of large crystallites with a specific surface of the order of 1 m2/g. It is indicated that the physical interpretation of the exchange process does not require the existence of separate departments, each with its own kinetic factor, but that the exchange may be simply related to the exponential change in the free energy of the reaction. For the reaction $$(Ca)_5 (PO_4 )_3 OH_{solid} + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F_{solid} + (OH^ - )$$ the thermodynamic constant has been calculated to be 101.26, implying that fluorapatite always will form at the expense of hydroxyapatite under physiologic conditions. This transformation will be furthered by lowering the pH.
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  • 12
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    Cell & tissue research 121 (1971), S. 377-441 
    ISSN: 1432-0878
    Keywords: Visual system ; Insects diptera ; Lamina ganglionaris ; Optic cartridges ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of optic cartridges in the frontal part of the lamina ganglionaris (the outermost synaptic region of the visual system of insects) has been analysed from selective and reduced silver stained preparations. The results, obtained from studies on five different species of Diptera, confirm that six retinula cells, together situated in a single ommatidium, project to six optic cartridges in a manner no different from that described by Braitenberg (1967) from Musca domestica. Each optic cartridge contains five first order interneurons (monopolar cells) which project together to a single column in the second synaptic region, the medulla. The dendritic arrangement of two of these neurons (L1 and L2) indicates that they must make contact with all six retinula cell terminals of a cartridge (R1–R6). Two others (L3 and L5) have processes that reach to only some of the retinula cell endings. A fifth form of monopolar cell (L4) sometimes has an arrangement of processes which could establish contact with all six retinula cells: other cells of the same type may contact only a proportion of them. This neuron (L4) also has an arrangement of collaterals such as to allow lateral interaction between neigbouring optic cartridges. The processes of the other four monopolar cells (L1, L2, L3 and L5) are usually contained within a single cartridge. In addition to these elements there is a pair of receptor prolongations (the long visual fibres, R7 and R8) that bypasses all other elements of a cartridge, including the receptor terminals R1–R6, and finally terminates in the medulla. Four types of neurons, which are derived from perikarya lying just beneath or just above the second synaptic region, send fibres across the first optic chiasma to the lamina. Like all the other interneuronal elements of cartridges the terminals of these so-called “centrifugal” cells have characteristic topographical relationships with the cyclic arrangement of retinula cell terminals. Apart from the above mentioned neurons there is also a system of tangential fibres whose processes invade single cartridges but which together could provide a substrate for relaying information to the medulla derived from aggregates of cartridges. Optic cartridges contain at least 15 neural elements other than retinula cells. This complex structure is discussed with respect to the receptor physiology, as it is known from electrophysiological and behavioural experiments. The arrangements of neurons in cartridges is tentatively interpreted as a means of providing at least 6 separate channels of information to the medulla, four of which may serve special functions such as relaying color coded information or information about the angle of polarised light at high light intensities.
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  • 13
    ISSN: 1432-0878
    Keywords: Vital staining ; Fibroblasts ; Autophagic vacuoles ; Influence of fixatives ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Fibroblastenkulturen wurden mit Mepacrin (Atebrin®), Neutralrot und Toluidinblau unter vergleichbaren Bedingungen vitalgefärbt. Die Farbstoffe induzieren die Bildung autophagischer Vakuolen (Autolysosomen) im Cytoplasma. Die Eignung von sieben verschiedenen Fixantien zur Erhaltung dieser im lichtmikroskopischen Sinn neugebildeten Strukturen wurde untersucht. Kriterien der jeweiligen Fixationsleistung waren einmal die Erhaltung der autophagischen Vakuolen an sich, zum anderen die Erhaltung ihrer farbstoffabhängigen, morphologischen Individualität. Als wenig leistungsfähig haben sich erwiesen die Lösungen nach Carnoy und Bouin sowie Formol. Glutaraldehyd bewahrt die Lysosomenstruktur befriedigend, jedoch nicht ausreichend stabil für weitere, etwa histochemische, Eingriffe. Kaliumbichromat gewährleistet bessere Stabilität, jedoch nur geringe Lebensähnlichkeit der Autolysosomen. OsO4 und NaMnO4 sind den anderen Fixantien hinsichtlich der Erfüllung beider Kriterien deutlich überlegen. Die Befunde werden mit dem lipidstabilisierenden Effekt, den beide Metalloxydverbindungen an den phospholipidreichen Autolysosomen ausüben, in Zusammenhang gebracht. Unterschiede in der Wirkung ließen sich nach Anwendung von OsO4 und NaMnO4 an den AV nachweisen: Mepacrin-AV werden durch OsO4 etwas lebensähnlicher erhalten als durch NaMnO4. Die Neutralrot-AV und Toluidinblau-AV mit deutlicher vakuolärer Struktur werden nur durch Permanganat im Zusammenhang erhalten, mit deutlicher Abgrenzung der Toluidinblau-induzierten von den Neutralrot-induzierten Autolysosomen. Nach Osmium- und Permanganatfixation zeigen die Zellkulturen starke Affinität zu Methylenblau, nicht Eosin. Nur die OsO4-fixierten Autolysosomen halten gegenüber Alkoholeinwirkung ihre Anfärbung im wesentlichen bei. Die Befunde werden diskutiert.
    Notes: Summary Fibroblasts grown in monolayer were subjected to vital staining by mepacrine (Atebrine®), neutral red and toludine blue under comparable conditions. These dyes induce the formation of autophagic vacuoles (autolysosomes) in the cytoplasm. The preservation of these structures, which are considered to be newly formed in the dimension of the light microscope, by seven different fixatives has been examined. The criteria employed to assess the performance of each fixative consisted of 1. the preservation of the autophagic vacuoles per se and 2. their dye-dependent morphological characteristics. Fixation by Carnoy's or Bouin's solution as well as by formaline gave poor results. Glutaraldehyde preserved lysosomal structure satisfactorily, but not adequately for further application of histochemical methods. Potassium dichromate has a stabilizing effect on autophagic vacuoles, however, structures are not equivalent to those observed in living cells. Osmium tetroxide (OsO4) and sodium permanganate (NaMnO4) are superior to the other fixatives with regard to the afore mentioned criteria. These observations are explained by the wellknown lipid-stabilizing effect which both metal oxides are expected to exert on autolysosomes with their high content of phospholipids. After fixation with OsO4 and NaMnO4 diverging effects on autophagic vacuoles could be ascertained. Mepacrine-induced autophagic vacuoles are preserved somewhat more accurately by OsO4 than by NaMnO4. Autolysosomes induced by neutral red and toluidine blue display a more vacuolated appearance and are preserved as a whole only by permanganate. Distinct differences exist between autophagic vacuoles induced by toluidine blue and those induced by neutral red. After fixation by OsO4 and NaMnO4 cells from culture display a strong affinity to methylene blue, but not to eosin. The staining of autolysosomes by methylene blue is resistant to ethanol after fixation in OsO4 only. The results are discussed.
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    Cell & tissue research 130 (1972), S. 378-388 
    ISSN: 1432-0878
    Keywords: Arteries ; Children ; Structure ; Pattern of calcification ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gross calcifications of the common iliac and internal iliac arteries represent a common finding in newborn children and infants. In both arteries, the calcific deposits regularly appear in certain areas of the arterial luminal surface only, whereas the other parts of the arterial wall remain free of gross lesions even in cases with a pronounced calcification. In the common iliac artery, the lateral wall of the vessel and the adjacent sectors of the anterior and posterior wall represent the predilection site of calcific deposits. In the internal iliac artery, the gross calcifications have been regularly demonstrated in the dorso-medial wall. The predominant localisation of the calcification in these parts of the vessels and its absence in the others depend on the definite structural features of the arterial tube and different affinity for calcium of the individual structural elements. In both iliac arteries, only the primary internal elastic membrane undergoes early calcification. However, unlike the most muscular arteries, this membrane is not developed in the whole arterial circumference of the common iliac and internal iliac arteries, but is absent in large areas of their arterial luminal layer. In these areas, the subendothelial or subintimal elastic layers are formed by the networks of longitudinally arranged elastic fibers or membraneous elastic structures which arise from the elastic networks with the further growth. These elastic elements always stay free of calcific deposits. The structural features found in both iliac arteries may be important for the development of the later pathological changes.
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  • 15
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    Cell & tissue research 129 (1972), S. 533-547 
    ISSN: 1432-0878
    Keywords: Epiphysis ; Circumventricular structures of the epithalamus ; Elephant ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die dorsale Wand des Epithalamus des Elefanten enthält zwei Aussackungen, den langen Recessus suprapinealis (RS), der mit Plexus chorioideus gefüllt ist, und den kurzen breiten Recessus pinealis (RP). Die dickeren Wandpartien beider Recessus bestehen überwiegend aus Pinealgewebe mit Pinealocyten. Das Ependym des Epithalamus bildet an fünf Orten circumventrikuläre Strukturen (CS); drei dieser CS gehören zum Subcommissuralorgan. Das Ependym mit der höchsten Aktivität liegt auf der unteren Lippe und in den spitzen lateralen Hörnern des RP. Dieses Epithel trägt Kinocilien und besitzt Zellprotrusionen; es ist mäßig gomoripositiv. Über die Verteilung der verschiedenen Kennzeichen der CS-Strukturen gibt eine Tabelle Auskunft. In der lateralen Wand des Epithalamus unter der Commissura habenularis liegen die Verrucae epithalami, die unterschiedlich tiefe ependymbedeckte Spalten besitzen. Die mögliche funktionelle Bedeutung dieser Strukturen wird kurz erörtert.
    Notes: Summary The dorsal wall of the epithalamus of the elephant has two evaginations: the long recessus suprapinealis (RS) filled with plexus chorioideus and the short and wide recessus pinealis (RP). The thick part of the wall of both recessus consists mainly of pineal tissue with pinealocytes. The ependyma of the epithalamic region has about 5 loci with circumventricular formations (CS), three of them belonging to the subcommissural organ. The ependyma with equivalents of high activity is situated in the lower lip and in the lateral tapering corners of the RP. This epithelium bears kinocilia and shows protrusions of the cells extending into the ventricle, it is fairly gomoripositive. Details concerning the structural differences in the various loci of CS are described. There are some verrucae epithalami in the lateral wall of the epithalamus below the commissura habenularis having more or less deep clefts covered with ependyma. The possible functions of these structures are briefly discussed.
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  • 16
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    Cell & tissue research 135 (1972), S. 415-438 
    ISSN: 1432-0878
    Keywords: Brain stem ; Human ; Dorsal glossopharyngeus vagus-complex ; Lipofuscin ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit Hilfe einer neu entwickelten Methode zur Darstellung von Neurolipofuscinen wird das Pigmentbild des dorsalen Glossopharyngeus- und Vagusgebietes beschrieben. Da außer wenigen elastischen Fasern nur die Lipofuscingranula, welche in Nervenzellen gespeichert sind, angefärbt werden, können Schnitte bis zu einer Dicke von 800 μ verwendet werden. Sie lassen bei stereomikroskopischer Betrachtung die Grenzen von Kerngebieten meist deutlich erkennen, da durch die Übereinanderprojektion zahlreicher Neurone auch geringe Unterschiede in der Dichte der Zellen, sowie in der Art und dem Ausmaß ihrer Pigmentierung hervortreten. Das dorsale Glossopharyngeus- und Vagusgebiet wird in elf Kerne unterteilt. Seinen caudalen Pol bilden der Nucleus terminalis caudalis alae cinereae, der Nucleus commissuralis und parvocellularis. Im mittleren Bereich liegen zahlreiche Kerne von kennzeichnender Gestalt nahe beieinander. Der Nucleus pigmentosus nervi vagi hüllt das Gesamtgebiet ein und füllt die Räume zwischen den Kernen aus. Der Nucleus alaris nervi vagi durchzieht als breite Zellplatte den ganzen mittleren Teil. Seine großen Neurone speichern Lipofuscinkörnchen nicht nur in den Perikaryen sondern auch in Form langer Pigmentspindeln in den Dendriten. Im kleinzelligen Gebiet lateral vom alaren Kern werden ein Nucleus terminalis intermedius alae cinereae, der Kern der Area postrema, ein Nucleus tractus solitarii, ein Nucleus gelatinosus, sowie ein oraler Terminalkern der Ala cinerea voneinander unterschieden. In allen Terminalkernen findet sich reichlich Dendritenpigment neben den kräftig gefärbten Lipofuscinkegeln in den Zelleibern. An der Grenze zum oralen Abschnitt des Gesamtgebietes vermindert sich die Dichte der Pigmentierung. Hier liegt in der Fortsetzung des alaren Vaguskernes der Nucleus salivatorius inferior. Eine so weitgehende Untergliederung des Glossopharyngeus- und Vagusgebietes steht in Widerspruch zu den Darstellungen zahlreicher Autoren. Vor allem im kleinzelligen Bereich, der meist als ein einheitliches Areal aufgefaßt wird, können mit Hilfe der Pigmentarchitektonik die drei Terminalkerne der Ala cinerea eindeutig vom eigentlichen Kern des Solitärbündels und vom Nucleus gelatinosus unterschieden werden. Außerdem stellt sich heraus, daß die Gesamtheit der melaninhaltigen Neurone im Vagusgebiet, zusammen mit einem weiteren großen Zelltyp, der reichlich mit Lipofuscin beladen ist, ein eigenes kompliziert geformtes Kerngebiet bilden, das sicher von den übrigen Kernen, auch von dem gleichfalls großzelligen Nucleus alaris abgetrennt werden kann.
    Notes: Summary By means of a newly developed method for the demonstration of neurolipofuscines the distribution of pigments in the dorsal glossopharyngeus-vagus-complex is described. Since apart from few elastic fibers only the lipofuscin granules which are stored in neurons are stained, sections up to 800 μ can be investigated. Under the stereomicroscope they show in general clearly the borders of nuclei, since because of the superposition of numerous neurons also slight differences in respect of the density of the cells and type and extent of their pigmentation show up clearly. The dorsal glossopharyngeus-vagus-complex of the human is subdivided into eleven nuclei. Its caudal pole is formed by the nucleus terminalis caudalis alae cinereae, the nucleus commissuralis and parvocellularis. In the middle portion several nuclei of characteristic shape lie closely together. The nucleus pigmentosus nervi vagi envelopes the whole complex and fills the spaces between the nuclei. The nucleus alaris nervi vagi forms a broad plate of cells extending over the whole length of the middle portion. Its large neurons do not only store the lipofuscin granules in their perikarya but also in form of elongated pigment spindles in the dendrites. In the parvicellular parts lateral of the nucleus alaris a nucleus terminalis intermedius alae cinereae, a nucleus of the area postrema, a nucleus tractus solitarii, a nucleus gelatinosus, and a nucleus terminalis oralis alae cinereae are to be distinguished. In all terminal nuclei abundant pigment spindles of the dendrites occur beside the heavily stained lipofuscin pyramids in the perikarya. At the border of the oral part of the complex the density of pigmentation decreases. Here, in continuity of the nucleus alaris, the nucleus salivatorius inferior is situated. Such an extensive subdivision of the glossopharyngeus — vagus-complex of the human is in contrast to the description of numerous authors. Especially in the parvicellular part, which generally is described as a uniform area, by means of pigment architecture unequivocally the three terminal nuclei of the ala cinerea can be distinguished from the nucleus tractus solitarii proper and the nucleus gelatinosus. In addition it becomes apparent by the pigment architecture that the whole population of melanin containing neurons in the vagus-complex, together with a further large cell type, which stores vast amounts of lipofuscin granules, forms a distinctive nucleus which can be separated with certainty from the other nuclei, as well as the equally magnocellular nucleus alaris.
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  • 17
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    Cell & tissue research 139 (1973), S. 179-200 
    ISSN: 1432-0878
    Keywords: Retino-preoptic pathway ; Optic tracts ; Rana temporaria ; Light microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The optic tracts and centres of optic terminals of Rana temporaria have been investigated with silver impregnation techniques after unilaterally cutting the optic nerve and autoradiographically after injection of a mixture of tritiated amino acids into the vitreous body of the left eye. The observations on the course of the optic tracts and on the optic terminals in the thalamus and optic tectum are to a great extent in agreement with those of other authors. The probability of a retino-preoptic pathway is supported by the detection of fibres running in dorsal direction in front of the place where the optic nerve penetrates the brain. In horizontal sections these fibres can be seen deviating from the optic tract, covering a short distance in frontal direction and then turning upward under an angle of about 90 degrees. They disappear between the ventral aldehyde-fuchsin positive cells of the preoptic nucleus. The ventral and median parts of the ipsilateral preoptic nucleus contain fragments of degenerated fibres. Autoradiographic data are also in favour of the presence of an ipsilateral retino-preoptic tract. After carefully counting the number of grains over left and right preoptic nucleus, it appeared that over the ventral and median parts of the left preoptic nucleus more grains occur than over the identical areas of the right one.
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  • 18
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    Cell & tissue research 139 (1973), S. 473-485 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Rabbit ; Architecture ; Autonomic innervation ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A light microscopic investigation of the rabbit pineal gland with the aid of silver-stained sections gave the following results. In the gland a medulla and a cortex can be distinguished, the medulla containing so-called light and dark pinealocytes, the cortex only light ones. Autonomic nerve fibres reach the pineal organ by two routes: (1) via the perivascular spaces of pineal blood vessels and (2) via two distinct nerve bundles, the nervi conarii. Bilateral superior cervical ganglionectomy revealed that these pinealo-petal nerve fibres are mainly orthosympathetic postganglionic. Intramural pineal neurones with synaptic-like structures on their cell bodies and dendrites point to the presence of a parasympathetic innervation next to the orthosympathetic one. Direct afferent or efferent neural connections with the brain appeared to be absent.
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  • 19
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Rat ; Gonadotrophic cells ; Cycle, influence of testosterone ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 4-day cyclic adult female Wistar rats were injected subcutaneously with testosterone propionate on diestrus 1 at 16:00 and on diestrus 2 at 10:00 respectively. Non-injected females served as controls. Autopsy was performed on diestrus 2 at 23:00, and on proestrus at 14:00 and 17:00 respectively. The blue Alcian-PAS staining was used to evidence FSH (β) and LH (γ) pituitary cells. In control animals and in diestrus 2 injected females only a small number of FSH cells could be detected on diestrus 2 at 23:00. This number increased markedly on proestrus at 14:00 and decreased on proestrus at 17:00. A similar evolution was observed in diestrus 1 testosterone injected females, but the number of FSH cells appeared higher at any stage of autopsy in these females than in diestrus 2 injected females and in control rats. In control females, numerous LH cells were observed on diestrus 2 at 23:00. The number of these cells was diminished on proestrus at 14:00 and still more at 17:00. On the contrary few LH cells were detected in testosterone injected females on the evening of diestrus 2. An increase of these cells occurred on proestrus at 14:00, followed at 17:00 by only a weak diminution as established by comparison with control animals. An inhibition of FSH release and a suppression of the proestrus surge of LH were therefore supposed to cause, on one hand, the slowing up of follicular growth observed in diestrus 1 injected females and, on the other hand, the blockage of ovulation noted in both diestrus 1 and diestrus 2 treated animals.
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  • 20
    ISSN: 1432-0878
    Keywords: Hippocampal region (rat) ; Distribution of dehydrogenases ; Postnatal development ; Histochemistry ; Light microscopy
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    Notes: Summary Succinate-, α-glycerophosphate-, NADH-, and NADPH dehydrogenases (tetrazolium reductases) were studied histochemically in brain sections. The distribution of these enzymes in the hippocampal region was mapped in different postnatal stages. In addition to the hippocampus and the dentate area which have also been dealt with by other authors, the description includes the entorhinal area, parasubiculum, presubiculum, and subiculum. In all the areas of the hippocampal region the enzyme activity is first localized mainly in cell bodies. Activity in the neuropil shows a tendency to increase with age throughout the stages studied. Examples of particularly early or late differentiation of the histochemical pattern exist. Thus already after 4–6 days the differentiated staining pattern in the hippocampal layers as seen in the adult, begins to appear. In the entorhinal area the early enzyme distribution agrees with that in the adult and facilitates identification of its layers. After 22 days the fundamental enzyme chemoarchitectonics of the adult rat brain has been obtained. Histochemical characteristics of the different areas, support the view that the hippocampal region constitutes an entity.
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  • 21
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    Cell & tissue research 141 (1973), S. 375-400 
    ISSN: 1432-0878
    Keywords: Hippocampal region (rat) ; AChE distribution ; Postnatal development ; Histochemistry ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Acetylcholinesterase (AChE) in the hippocampal region was studied histochemically in different postnatal stages. Enzyme changes are described for the hippocampus proper, the dentate area, the entorhinal area, parasubiculum, area retrosplenialis e, presubiculum, and subiculum. In 1 day old animals there are only traces of AChE in solitary perikarya of the hippocampal stratum radiatum, while there is no activity in the neuropil. This is in contrast to other regions of the brain, e.g. the corpus striatum and the medial septum. Enzyme activity in the neuropil, although very weak, is seen clearly on the 2nd day. While the enzyme reaction in some cell soma seems to be permanent and also present in adult rats, other cell bodies, e.g. in the entorhinal area lose AChE activity during the last part of the 2nd week and in the 3rd week. Similar observations have been made on other parts of the central nervous system. The main features of chemodifferentiation in the hippocampal region seem to be completed by the end of the third week, although most layers and areas have not yet achieved the same high staining intensity as seen in the adult rats.
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  • 22
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    Cell & tissue research 142 (1973), S. 131-146 
    ISSN: 1432-0878
    Keywords: Epidermis (mouse) ; Pattern of organization ; Proliferation kinetics ; Three-dimensional analysis ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Es wird eine Methode zur Herstellung, Montierung und Färbung von epidermalen Häutchenpräparaten zur dreidimensionalen Analyse des Epidermis-Aufbaues beschrieben. Eine Kombination mit der Histoautoradiographie ist bedingt möglich. Damit ist eine Basis für weitere Untersuchungen mit neuer Fragestellung geschaffen. 2. Die untersuchten Objekte Mäuseohr und Rückenhaut zeigen eine bisher unbekannte, auffallende Musterbildung mit Zuordnung bestimmter interfollikulärer basaler Gruppen zu Zellen des Stratum spinosum und des Stratum corneum. Es handelt sich um rosettenähnliche Gebilde aus mehreren peripheren Basalzellen und meist einer zentralen Spinosumzelle. 3. Die Bedeutung der Befunde für die normale wie für die pathologische Regeneration und Neoplasie der Epidermis ist offen. Es werden Beziehungen zum Regenerationsmodus und damit zur Proliferationskinetik der Epidermis diskutiert. In diesem Zusammenhang sind die Untersuchungen auch für die Humanpathologie relevant.
    Notes: Summary 1. A method for the preparation, mounting, and staining of thin preparations of mouse epidermis is described, which allows a three-dimensional analysis of epidermal structure. A limited combination of this technique with histo-autoradiography is possible, thereby presenting a broader basis for further investigations. 2. Both ear and back skin show a striking, previously unrecognized pattern of organization, in which definite interfollicular basal cell groups are oriented towards cells of the stratum spinosum and stratum corneum. A rosettelike picture of many peripheral basal cells and, in most instances, a central spinosum cell is found. 3. The significance of our findings for normal and pathological regenerations as well as neoplasia of the epidermis remains open. We discuss relationships to the mode of regeneration and thus the kinetics of proliferation in the epidermis. Our investigations are also relevant for human pathology in this regard.
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    Cell & tissue research 148 (1974), S. 347-358 
    ISSN: 1432-0878
    Keywords: Pituitary, catfish ; Cell-types ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Seven distinct types of secretory cell can be differentiated in the pituitary gland of the fresh-water catfish, Heteropneustes fossilis. The presumptive prolactin cells appeared completely degranulated. Corticotrophs and thyrotrophs were identified by their response to metopirone and β methasol or to thiourea and thyroxine respectively. A single gonadotrophic cell type was identified, which showed a progressive increase in nuclear size, cell size and cytoplasmic granulation related to vitellogenesis in the ovary. Presumptive somatotrophs did not react to any of the experimental treatments used. In the pars intermedia, one of the two cell types — the PbH+ cells — showed an increase in activity in response to metopirone, thyroxine and reserpine; the PAS+ cells in this region remained relatively inactive.
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  • 24
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    Cell & tissue research 144 (1973), S. 573-583 
    ISSN: 1432-0878
    Keywords: Gills ; Tilapia mossambica ; Blood vessels ; Arteriovenous anastomoses ; Light microscopy ; Quantitative evaluation
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    Topics: Biology , Medicine
    Notes: Summary The non-respiratory vascular system of T. mossambica gill filaments was studied in serial longitudinal and cross sections. Comparatively few scattered vascular communications occur between the afferent filament artery and the central venous sinus (AVAaff). The efferent filament artery, however, is connected by regularly arranged anastomoses (AVAeff), directly, and sometimes indirectly via nutritive vessels, to the central sinus. These AVAeff are about as numerous as lamellae counted on one side of each filament, although they diminish slightly in number towards the filament base. The relation AVAeff to AVAaff was 17.6:1 in the distal and 17.8:1 in the basal filamental region, while in the tip region of 7 filaments 126 AVAeff but only 1 AVAaff were encountered. No direct connection between the lamellar lacunae and the central sinus was detected. According to these results, non-respiratory intrafilamental blood shunting appears unlikely. AVAeff are assumed to be the main route for blood entering the central venous sinus which would consequently flow into the branchial veins.
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  • 25
    ISSN: 1432-0878
    Keywords: Entorhinal area ; Guinea pig ; Subdivision ; Distribution of heavy metal ; Light microscopy
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    Notes: Summary The boundary line dividing the entorhinal area into a pars medialis and a pars lateralis has been determined in adult guinea pig by comparison of graphic maps of the distribution of heavy metals and of the terminal field of a presubiculum → entorhinal area projection. The virtual coincidence of the histochemically and hodologically based subdivisions strongly supports the assumption that the obtained boundary line represents the true location of a functional limit between the two entorhinal parts.
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  • 26
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    Cell & tissue research 151 (1974), S. 219-228 
    ISSN: 1432-0878
    Keywords: Cell death ; Central nervous system ; Embryogenesis of Calliphora (Insecta) ; Vital staining ; Light microscopy
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    Notes: Summary During the late embryonic period, cell death occurs in the central nervous system of Calliphora erythrocephala. The degenerating cells are small and rounded, contain a pyknotic nucleus, and selectively accumulate basic vital dyes such as nile blue sulphate and acridine orange. The number of degenerating cells is highest 13–15 hours after oviposition and decreases during the shortening of the ventral nerve cord. Nevertheless, these degenerating cells do not represent a morphogenetic phenomenon, since their number is too small to account for the 55% decrease in the length of the ventral nerve cord. In all probability the pyknoses seen in the central nervous system of this holometabolic insect are to be interpreted as phylogenetic degenerations of clearly vestigial neuroblasts that have lost functions they might have retained in the larvae of insects in lower orders, for instance the innervation of legs, wings, a larger number of abdominal segments, etc. About half of the pyknoses occur in pairs.
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  • 27
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    Cell & tissue research 141 (1973), S. 493-503 
    ISSN: 1432-0878
    Keywords: Pituitary ; Glomerular body ; Marine teleost ; Hexagrammos otakii ; Larval osmoregulation ; Light microscopy
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    Notes: Summary In the larvae of the marine teleost, Hexagrammos otakii, the prolactin, ACTH, STH and pars-intermedia cells as well as the neurohypophysis and glomerular body showed no histological change at the time of hatching. These cells or organs do not seem to be specifically involved in the mechanisms of adjustment to the hypertonic osmotic stress at this time. The size of the nuclei of the prolactin cells increased in fresh-water (F. W.) and that of the ACTH cells decreased in 2/3, 1/2 and 1/3 sea-water (S.W.). The amount of chrome-alum haematoxylin-positive material in the neurohypophysis of fish immersed in 1/2 S.W., 1/3 S.W. and F.W. was less than that of the control fish. There was a difference in the glomerular ratio between the fish kept in F. W. and control fish. And the red blood cells in the glomerulus of the larvae kept in 1/2 and 1/3 S.W. apparently increased in number in comparison with the control fish.
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  • 28
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    Cell & tissue research 143 (1973), S. 535-547 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Rat ; Mitoses, topographic distribution ; Influence of fixation ; Light microscopy
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    Description / Table of Contents: Résumé Les mitoses de l'adénohypophyse du rat mâle ont été examinées comparativement après fixation par perfusion et après fixation par immersion. Après fixation par perfusion la répartition topographique des mitoses dans le parenchyme est homogène, et l'index mitotique est de 1,85 pour 1 000 cellules. Après fixation par immersion, la densité des mitoses décroit de la périphérie vers le centre, et l'index mitotique n'est que de 0,80 mitoses pour 1 000 cellules. La lenteur de pénétration du fixateur pendant l'immersion est tenue pour principal responsable des différences observées. Elle entraîne une modification de l'aspect des mitoses, telle que plus de la moitié d'entre elles ne sont pas identifiables et échappent aux comptages.
    Notes: Summary The mitoses of the adenohypophysis in male rats have been observed comparatively after fixation by perfusion and fixation by immersion. After fixation by perfusion, the topographic distribution of mitoses throughout the parenchyma is homogenous and the mitotic index is 1.85 for 1 000 cells. After fixation by immersion, the density of the mitoses is decreasing from the periphery towards the center and the mitotic index is only 0.80 for 1 000 cells. The slow penetration of the fixative during fixation by immersion is considered to be the main cause in the differences observed. This slow action causes a modification in the aspect of the mitoses, and more than fifty percent of them cannot be identified and escape to the counts.
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    Cell & tissue research 147 (1974), S. 249-257 
    ISSN: 1432-0878
    Keywords: Chromosomes ; Action of colchicine ; Botryllus schlosseri (Ascidia) ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary The course of c-mitosis in early embryos ofBotryllus schlosseri is arrested in a bizarre c-metaphase configuration in which the chromosome arms are tightly paired and sister kinetochores are well separated. This new type of c-metaphase chromosomes occurs because kinetochores are normally separated during prometaphase and sister c-chromatids tend to adhere to each other. Abnormal activity of sister kinetochores, chromosome fragmentation, adherence between chromosomes, overcondensation of chromosomes and bipolar arrangement of the c-pairs, are some additional effects induced by colchicine treatment of oocyte cleaving eggs ofB. schlosseri that have been studied. The behaviour of both normal and c-chromosomes ofB. schlosseri suggests that the forces acting upon kinetochores reach a minimum at metaphase and that they are not diminished by colchicine treatment.
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  • 30
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    Cell & tissue research 144 (1973), S. 353-368 
    ISSN: 1432-0878
    Keywords: Epidermis ; Bufo bufo ; Moulting cycle ; Structure ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Skin samples were taken from 17 toads (Bufo bufo) in various phases of the moulting cycle. The phase was determined by recording a number of moulting intervals prior to sacrifice and by study of the macroscopic appearance of the skin and the moulting behaviour at sacrifice. Eight of the toads were in the moult when the samples were taken. Characteristic morphological changes were found to be restricted to a period immediately prior to and after shedding of the slough. Chemical changes of the membranes of stratum corneum (or material adhered to them) were observed already prior to adoption of the moulting posture. The separation from the underlying epidermis prior to shedding was accompanied by a swelling of the stratum corneum cells. After final detachment of the slough the replacement layer was differentiated into a new stratum corneum within 24 hours. Significant changes in the morphology of the flask cells were not observed. The findings are discussed with emphasis on the processes of separation and differentiation of the stratum corneum. Based on the morphology of the epidermis the following terminology is proposed for the phases of the moulting cycle: Intermoult phase, preparation phase, early shedding phase, late shedding phase, and differentiation phase.
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    Cell & tissue research 150 (1974), S. 95-105 
    ISSN: 1432-0878
    Keywords: Mucosal mast cells ; Rat ; Compound 48/80 ; Degranulation, Release ; Light microscopy ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Mast cells in the tongue and lamina propria of the duodenal mucosa, representing two cell types with different morphological, histochemical and functional properties have been studied under the electron microscope. Both cell types were found to contain similar moderately electron dense and homogeneous granules surrounded by a tight membrane constituting the basic ultrastructural characteristics of mast cells. The mucosal mast cells, however, contained fewer granules per cell and the individual granules often exhibited considerable variation in size. In addition the mucosal mast cells, unlike those of the tongue, peritoneum and skin, had a smooth plasma membrane lacking microvilli and possessed irregularly shaped or lobulated nuclei. In the tongue mast cells, administration of Compound 48/80 caused the formation of vacuoles around the granules, expulsion of granules from the cells and disintegration of the granular matrix, but no changes that could be attributed to 48/80 could be found in the mucosal mast cells.
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    Cell & tissue research 150 (1974), S. 213-229 
    ISSN: 1432-0878
    Keywords: Nerve cells ; Regeneration ; Neurosecretion ; Hydra viridis, littoralis ; Light microscopy
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    Notes: Summary Using whole mount preparations, nerve cells at the cut surface (head region) and also the peduncular-basal disk region were studied during various stages of regeneration (zero hour — 96 h) in Hydra. Leucomethylene blue staining technique allows excellent stainability of nerve cells and thus a statistical count of them at the specified stages of regeneration was obtained. Within 1 h after transection a significant increase (P 〈 0.001) in release of neurosecretory droplets occurs. Between 4 and 15 h of regeneration the number of perikarya remains relatively constant, but the number of processes increases by 200%. This indicates that neurons in Hydra have the capacity to regenerate their processes. Their growth in length is dramatically illustrated at 18 hrs. of regeneration. This degree of anastomosing arrangement is not observed in any other stage of regeneration. After this time the majority of processes break down releasing the neurosecretory materials. A study of the number of perikarya, the number of neurites and the number of neurosecretory droplets in regenerating animals reveals a continuous increase in the number of nerve cells and neurosecretory droplets released for up to 24 h. With the accumulation of nerve cells at the cut surface (24 h of regeneration) there is a simultaneous appearance of tentacle outpushings. The tentacles increase in number and length during the subsequent periods of regeneration. As the regenerative process approaches completion (72–96 h) the number of neurosecretory droplets released decreases, approaching the pre-transection levels as seen in normal animals. It is suggested that the neurosecretory material may act as a “trophic” agent which stimulates differentiation of interstitial cells into nerve cells and thus influences the regenerative process.
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    Cell & tissue research 133 (1972), S. 367-375 
    ISSN: 1432-0878
    Keywords: Nucleolar types ; Maturing erythroblasts (frog) ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Frog erythroblasts were studied in summer animals with a very active as well as reduced erythropoiesis due to experimental hibernation, the latter being administered in order to get more information on the frequency of various nucleolar types in maturing cells. The results suggest that nucleoli with nucleolonemata are a transitional nucleolar type between compact and ringshaped nucleoli. Since micronucleoli represent final nucleolar maturation changes and compact nucleoli are present in most immature cells, the sequence of nucleolar changes based on the frequency of investigated nucleolar types is as follows: compact nucleoli→nucleoli with nucleolonemata→ringshaped nucleoli→micronucleoli. The experimental hibernation produces a shift of nucleoli to less active and “maturer” nucleolar types in all stages of the erythroblastic maturation. In addition, the experimental hibernation produces the formation of ringshaped nucleoli in the first stages of the erythroblastic maturation which in summer animals usually contain compact nucleoli and/or nucleoli with distinct nucleolonemata.
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    Cell & tissue research 134 (1972), S. 439-458 
    ISSN: 1432-0878
    Keywords: Limbic system ; Amygdala ; Cat-cell types ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary The amygdaloid complex in the cat was studied in a series of Golgi preparations. Both the lateral and the basal nucleus are composed of the same two cell types, one of which (type P) resembles the pyramidal and the other (type S) the stellate neuron of the cortex. The cortical nucleus can be divided into three layers (I, II, and III–IV) which are made up of cells similar to those in the periamygdaloid cortex. In addition, there are sufficient differences in the organization of these layers to justify a subdivision of the cortical nucleus into lateral and medial parts. The dendrites of neurons in the medial part of the central nucleus, the medial nucleus and the anterior amygdaloid area undergo less branching and carry fewer spines than those of the type P cell. The neurons in the nucleus of the lateral olfactory tract are all of the pyramidal or modified pyramidal type. These findings are discussed in relation to those of previous investigators who employed the Nissl and Golgi methods.
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    Cell & tissue research 135 (1972), S. 27-43 
    ISSN: 1432-0878
    Keywords: Endocrine glands ; Male sexual organs ; Reptiles ; Influence of Metopirone ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Adrenals, pituitary glands, thyroids, testes and kidneys of metopirone-treated and control male lizards were studied by light microscopy. Pituitary-interrenal axis: A great hypertrophy and hyperplasia of the interrenal cells and the pituitary corticotrophs were found in the experimental group. Pituitary-thyroid axis: Metopirone-treated animals showed a moderate hypertrophy and degranulation of pituitary thyrotrophs, and signs of uneven hyperactivity of the thyroid. Pituitary-testicular axis: By effect of metopirone, a marked regression of pituitary interstitiotrophs and a virtual disappearance of the testicular interstitial gland took place. The second portion of the kidney sexual segments appeared degranulated as in castrated animals. The pituitary folliculotrophs and the seminiferous epithelium of the testis did not show alterations.
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    Cell & tissue research 148 (1974), S. 277-286 
    ISSN: 1432-0878
    Keywords: Insect visual system ; Apis mellifera ; Retina-lamina projection ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary The retina-lamina projection in the visual pathway of the bee was studied by the reduced silver and Golgi techniques. Two main types of visual cell axons (R-fibres) were found: (1) at least two forms of short visual fibres terminate at two levels in the lamina; (2) the long visual fibres cross the first optic chiasma and terminate at two different levels of higher order neurons in the medulla. Six short and three long visual fibres leave each retinula in the bee's eye. Whereas two types of short visual cells can be distinguished by the arborization patterns of Golgi-stained preparations, as well as by their fibre diameters, three different types of long visual fibres can be found. In each cartridge (“neuroommatidium”) the six short visual cells closely appose three monopolar cells (L-fibres, second order neurons). Thus each axon bundle crossing the first (or intermediate) chiasma contains at least six large argyrophilic fibres (three long visual cells and three monopolar cells), and these can be seen in cross-sections of reduced silver preparations. In addition, centrifugal fibres originating in the medulla and terminating in the lamina as well as amacrine (intrinsic) cells of the lamina have been resolved by Golgi impregnation.
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    Cell & tissue research 116 (1971), S. 119-135 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex difference ; Light microscopy ; Histometry
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    Description / Table of Contents: Zusammenfassung An 260 männlichen und weiblichen Sprague-Daweley-Ratten vom 0. Lebenstag bis zur 12. Lebenswoche wird die geschlechtsdifferente Entwicklung der Nebennierenrinde histologisch und histometrisch verfolgt. Von der 4. Lebenswoche an ist die weibliche Fasciculatazelle durch ein helles, fein-granuläres Cytoplasma ohne distinkt abgrenzbare Fettvakuolen ausgezeichnet, während beim Männchen in einem kompakten Cytoplasma zunehmend größere, deutlich begrenzte Vakuolen auftreten. Im Blindversuch gelingt aufgrund dieser Kriterien die Geschlechtsdiagnose mit großer Treffsicherheit. Nach histometrischen Untersuchungen sind die weiblichen Fasciculatakerne größer als die männlichen. Bei größerem Zellvolumen ist die Kernzahl/Flächeneinheit beim Weibchen von der Pubertät an kleiner. Die Glomerulosa und die inneren Rindenschichten zeigen keine Geschlechtsdifferenzen. Fermenthistochemisch ist eine Geschlechtsdifferenz nicht nachweisbar. Die relative Zellhypertrophie in der Fasciculata der weiblichen Nebennierenrinde ist das morphologische Äquivalent eines geschlechtsdifferenten Steroidmetabolismus bei der Ratte.
    Notes: Summary In 260 male and female Sprague-Dawley CD rats the sex dependent development of the adrenal cortex was studied histologically and by histometric procedures. Beginning in the 4th week of life the parenchymal cells in the fasciculata of the female animals are characterized by a light, finely granular cytoplasm without distinct lipid vacuoles. In the males, however, the cells show a dense, compact cytoplasm with clearly visible vacuoles increasing in size. In a blind test the sex diagnosis can be established with great accuracy. Histometrically the nuclei in the female fasciculata cells are larger than in the males. Furthermore, caused by a larger cell volume the number of nuclei per square unit is smaller in postpuberal females. The glomerulosa and the inner parts of the cortex do not show any sex differences, nor does enzyme histochemistry. The relative cellular hypertrophy in the fasciculata of the female adrenal cortex represents the morphologic equivalent of the sexual differences in the rats steroid metabolism.
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    Cell & tissue research 121 (1971), S. 442-454 
    ISSN: 1432-0878
    Keywords: Visual system ; Insects ; First optic chiasma ; Fibre projection ; Light microscopy
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    Topics: Biology , Medicine
    Notes: Summary Each optic cartridge in the lamina of Diptera1 gives rise to a bundle of fibres composed of the prolongations of at least 11 neurons (two first order receptors, R7 and R8, five monopolar cells, L1–L5 and four “centrifugal” cells, T1, T1a, C2 and C3). The bundles project to the outer surface of the second synaptic region, the medulla. The projection patterns of the bundles means that a point for point map of the cartridge arrangement in the lamina is conferred on the medulla. The cross-over of bundles, along the horizontal axis of the eye, merely reverses the lamina map on the medulla. All eleven fibres that enter a bundle at the lamina are contained within it as far as the medulla.
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    Cell & tissue research 131 (1972), S. 109-140 
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    Keywords: Deuterocerebrum ; Apis mellifera ; Sensory antennal fibres ; Experimental degeneration ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei Bienen wurden verschieden große Abschnitte eines Fühlers oder ein ganzer Fühler in Narkose abgetrennt. Nach Überlebenszeiten von einem bis zu neun Tagen wurden der Verlauf und die räumliche Verteilung der degenerierenden, sensorischen Antennenfasern im Zentralnervensystem untersucht und der Anteil der dickfaserigen Efferenz bestimmt. Folgende Befunde wurden erhoben: 1) Die Mehrheit der Glomeruli des Lobus antennalis ist in Knäuel und Hauben gegliedert; sensorische Antennenfasern ziehen hauptsächlich von außen zu den Glomerulihauben und endigen dort. 2) Ein Wulst aus feinen Faseraufzweigungen im Lobus antennalis im Bereich des Tractus olfactorioglobularis medialis wird ebenfalls von der Antenne (vom Pedicellus?) sensorisch versorgt. 3) Der größere Teil aller sensorischen Antennenfasern endigt zwar im Lobus antennalis, der Rest zieht jedoch weiter zum Lobus dorsalis. 4) Im Lobus dorsalis befinden sich Kleinglomeruli, in denen sensorische Antennenfasern endigen; daneben durchsetzt Antennenafferenz fast den gesamten Lobus dorsalis. 5) Ein Bündel dickerer, sensorischer Antennenfasern zieht durch den Lobus dorsalis weiter zum Protocerebrum und endigt im Bereich von Ocellar-Riesenfasern. 6) Ein weiteres Bündel aus dickeren, sensorischen Antennenfasern zieht durch den Lobus dorsalis in das Unterschlundganglion; zusammen mit dünneren, sensorischen Antennenfasern wird ein Schlauch aus Antennenafferenz um den Integumentnerven herum gebildet. 7) Sensorische Antennenfasern ziehen nur im Unterschlundganglion auf die kontralaterale Seite, im wesentlichen verteilt sich die Antennenafferenz jedoch ipsilateral. 8) Die aus ungefähr 20 Motoaxonen bestehende, dickfaserige Efferenz für die Antennenmuskeln verläßt die Neuropilemkalotte des Lobus dorsalis ganz lateral; meist 6 efferente Fasern ziehen im sensorisch-motorisch gemischten Antennennerven in die Antenne. 9) Im Lobus dorsalis umspinnen sensorische Antennenfasern ganz eng motorische Antennenfasern; sehr wahrscheinlich existieren an diesen Kontaktstellen Synapsen zwischen der Antennenafferenz und der Antennenefferenz ohne zwischengeschaltete Neurone. 10) Der Nerv vom Janetschen Chordotonalorgan an der Antennenbasis zieht direkt zum Lobus dorsalis und gabelt sich dort, der eine Zweig zieht in das Protocerebrum, der andere in das Unterschlundganglion.
    Notes: Summary In worker bees a varying number of antennal segments or whole antennae were removed. After postoperative survival times ranging from one to nine days the course and the spatial distribution of the degenerating sensory antennal fibres in the CNS were investigated; the amount of thick efferent antennal fibres was evaluated. 1) The major part of the glomeruli of the antennal lobe is organized into neuropile balls surrounded by fibre caps; sensory antennal fibres enter the caps primarily from outside to end there. 2) A worm like region consisting of fine nerve ramifications in the central neuropile of the antennal lobe next to the Tractus olfactorio-globularis medialis receives also sensory fibres from the antenna (possibly the pedicel). 3) Although the greater part of all sensory antennal nerve fibres terminates in the antennal lobe, a considerable part passes by to the dorsal lobe. 4) The dorsal lobe contains smaller glomeruli than the antennal lobe, where also sensory antennal fibres terminate; moreover sensory antennal fibres are found throughout the whole dorsal lobe. 5) A bundle of thicker sensory antennal fibres passes through the dorsal lobe to the protocerebrum to terminate next to giant fibres from the ocelli. 6) Another bundle of thicker sensory antennal fibres passes through the dorsal lobe to the subesophageal ganglion; together with thinner sensory antennal fibres it builds up a “tube” of afferent antennal fibres around the tegumentary nerve. 7) Sensory antennal fibres only in the subesophageal ganglion cross to the contralateral side; essentially their distribution is restricted to the ipsilateral side of the central nervous system. 8) There exist about 20 motor axons supplying the antennal muscles; they are the most laterally situated nerve fibres in the neuropile of the dorsal lobe; generally 6 efferent fibres together with the afferent antennal fibres constitute the mixed sensory-motor antennal nerve. 9) In the dorsal lobe sensory antennal nerve fibres end on antennal motor fibres; very probably in this region direct synaptic contacts between sensory and motor fibres without intermediate interneurons occur, thus permitting monosynaptic reflexes. 10) The nerve from Janet's antennal chordotonal organ goes directly to the dorsal lobe, where it bifurcates, one twig passing to the proto-cerebrum, the other to the subesophageal ganglion.
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    Cell & tissue research 136 (1973), S. 45-58 
    ISSN: 1432-0878
    Keywords: Chicken ; Bursa Fabricii ; Thymus ; Spleen ; Tonsilla caecalis ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bursa Fabricii, Thymus, Milz und Zäkaltonsillen von 63 Hühnern im Alter von 1 Tag bis zu 1 Jahr werden histologisch untersucht, wobei das Vorkommen der als bursaabhängig geltenden Keimzentren und Plasmazellen quantitativ erfaßt wird. Beide treten in der Milz und Tonsilla caecalis erst während des Reifestadiums der Bursa in zunehmender Menge auf. Mit Beginn der Bursainvolution werden Keimzentren und pyroninophile Zellen in der Milz selten, während in den Zäkaltonsillen kaum Veränderungen auftreten. Im Thymus verschiebt sich das Verhältnis zwischen Mark- und Rindenbreite zugunsten des Marks. Bei 8 Monate alten Tieren fehlt die Rinde vollständig. Plasmazellen treten im Thymusmark während des Reifestadiums der Bursa auf und nehmen mit dem Beginn deren Involution zu. In dem Zeitraum zwischen 2 Wochen und 5 Monaten ändert sich das Verhältnis zwischen reifen und unreifen Plasmazellen beständig zugunsten der reifen Plasmazellen.
    Notes: Summary Bursa of Fabricius, thymus, spleen and cecal tonsils were histologically examined with special reference to the number of bursa-dependent germinal centers and plasma cells in 63 chickens, 1 day to 1 year old. Both structures appear in spleen and cecal tonsils increasingly during the bursal maturity stage. At the beginning bursal involution, germinal centers and pyroninophilic cells become rare in the spleen, in contrary no changes appear in the cecal tonsils. The medulla cortex ratio of the thymus changes in favour of the medulla, in animals 8 months of age the cortex is absent. Plasma cells appear in the medulla of the thymus during the bursal maturity stage and increase in number with beginning involution. During the period of 2 weeks to 5 months the proportion between mature and immature plasma cells changes in favour of mature cells.
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    Cell & tissue research 139 (1973), S. 149-170 
    ISSN: 1432-0878
    Keywords: Suctorial disc ; Echeneis naucrates ; Sustentacular tissue ; Sense organs ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die lichtmikroskopische Untersuchung der Haftscheibe des Teleostiers Echeneis naucrates führte unter anderen zu folgenden Ergebnissen: 1. Das mehrschichtige, Schleimzellen enthaltende Epithel der Scheibe weist deutliche regionale Unterschiede auf. So ist auf der Dorsalfläche der flexiblen Randlippe eine an Schleimdrüsen besonders reiche bandförmige Zone ausgebildet. Ferner werden die Eingänge in die Taschen zwischen den Lamellen des Saugapparates und die Oberfläche der medianen Hautleiste von stark schleimbildendem Epithel umgeben bzw. bedeckt. Der Schleimstreifen der Haftscheibe wird als Einrichtung zur Abdichtung der Haftfläche gedeutet. 2. Im Drüsenfeld auf der Dorsalfläche der Randlippe liegen große Sinnesorgane vom Typus der Chemorezeptoren. Ihre Funktion besteht möglicherweise in der Prüfung der Oberfläche des Wirtes, an dem sich Echeneis festsaugt. Die Angaben von Houy (1910), wonach diese Sinnesorgane in der Wand eines Kanalsystems liegen und nicht intraepithelial, beruhen auf der Fehlinterpretation artifiziell entstandener Spalten. 3. Die interlamellären Taschen der Saugplatte werden von einem verhältnismäßig niedrigen und an Schleimzellen armen, gefältelten Epithel ausgekleidet. Es ist der Beanspruchung auf Dehnung angepaßt, die bei dem Ansaugen infolge Vertikalstellung der Lamellen der Scheibe auftritt. 4. Der ovale abgeplattete Stützgewebsstreifen innerhalb der Randlippe, dessen Gewebe von Houy (1910) nicht klassifiziert werden konnte, besteht aus hyalinzelligem Chondroidgewebe (Schaffer), das von kollagenen und elastischen Fasern, ferner von einem weitmaschigen Kapillarnetz durchsetzt wird. Zarte Septen aus Kollagenfilamenten umgeben jede einzelne Hyalinzelle. Das im Zentrum des Reifens gelegene univakuoläre Fettgewebe differenziert sich aus den Hyalinzellen des Chondroidgewebes, die ihrerseits von perichondralen Fibrozyten abstammen. Auch die innerhalb der Lamellen des Saugapparates gelegenen Knorpelformationen werden von hyalinzelligem Chondroidgewebe gebildet, das mit Fettgewebe in Zusammenhang steht. 5. Die Faserarchitektur des Randstreifens entspricht der trajektoriellen Bauweise des Hyalinknorpels.
    Notes: Summary A light microscopical study of the suctorial disc of the teleost Echeneis naucrates revealed the following details: 1. The stratified mucous-cell bearing epithelium of the disc shows distinctive regional differences. Thus the dorsal surface of the flexible marginal lip contains a peculiar glandular zone which is particularly rich in mucous cells. Furthermore, the openings to the pockets between the lamellae of the suction apparatus and the surface of the median dermal ridge are mucus producing zones. These areas are interpreted as devices for tightening. 2. In the mucous zone of the dorsal surface of the marginal lip are large sensory organs of chemoreceptor type. Possibly their function consists in the chemical assessment of the host's surface. The statement by Houy (1910) according to which these organs are located in the wall of a canalicular system rather than intraepithelially stems from his erroneous interpretation of artifactitious clefts. 3. The interlamellar pockets of the suction disc are lined by a low folded epithelium with relatively few mucous cells. It is capable of adjusting to the stretch caused by the tilting of the disc's lamellae during suction. 4. The oval flattened ring of sustentacular tissue within the marginal lip, which Houy (1910) was unable to classify, represents a chondroid tissue consisting mainly of hyaline cells (“hyalinzelliges Chondroidgewebe, Schaffer 1930”) and traversed by collagenous and elastic fibres. It also contains a wide-meshed capillary network. Each hyaline cell is surrounded by delicate septa formed by collagenous filaments. The unilocular adipose tissue in the ring's center develops from the hyaline cells of the chondroid tissue which in turn are derived from perichondrial fibrocytes. Also the cartilaginous structures within the lamellae of the suction apparatus are formed by the same chondroid tissue that is in connection with adipose tissue. 5. The spatial arrangement of the fibres and fibrils traversing the sustentacular tissue within the marginal lip corresponds to the trajectorial pattern of hyaline cartilage.
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    Cell & tissue research 137 (1973), S. 313-329 
    ISSN: 1432-0878
    Keywords: Nervous system ; Limulus polyphemus ; Abdominal ganglion ; Neurons ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the first abdominal ganglion of Limulus polyphemus (L.) was examined by reconstructions from stained serial sections. This ganglion, one of a chain of eight which form the ventral cord, is bilaterally symmetrical and shows the typical invertebrate division into two zones, cellular rind and fibrous core. The core of the ganglion comprises two major longitudinal tracts which are continuous with the connectives between the ganglia and four areas of regional neuropile which occur at the roots of the nerves developed from the ganglion. Minor tracts and neuropile are present. The rind is divided into several cell groups: U-shaped lobes around the nerve roots, a lateral lobe between the nerve roots and two cell layers along the ventral aspect. Six cell types are recognized: encapsulated unipolar cells, secretory unipolar cells (two types), encapsulated bipolar cells, “neuroglandular” bipolar cells and small non-encapsulated cells.
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    Cell & tissue research 140 (1973), S. 509-534 
    ISSN: 1432-0878
    Keywords: Genital tract ; Viviparous toad ; Cyclic variations ; Light microscopy ; Biometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'oviducte de Nectophrynoïdes occidentalis Angel, petit crapaud vivipare d'Afrique occidentale, peut être divisé en quatre parties: le pavillon, la trompe, l'utérus et le tronc commun utérin distal. Seul le pavillon ne varie pas au cours de l'année; il reste toujours transparent et dépourvu de cellules glandulaires. Un épithélium cilié tapisse sa lumière. La trompe est un conduit rectiligne de 7 à 10 millimètres de long qui peut être divisé en quatre segments principaux, différenciés par la constitution chimique des substances de la muqueuse. La structure de la trompe est relativement simple et comparable à celle des autres Vertébrés inférieurs. Elle apparait alternativement sous deux aspects principaux: trompe au repos et trompe active. La période de repos se poursuit pendant une bonne partie de la gestation; la reprise d'activité sécrétrice s'effectue plusieurs semaines avant la parturition et atteint son maximum dans les jours qui précèdent l'ovulation. L'utérus subit continuellement des remaniements. Tour à tour vide et gravide, il passe par trois phases essentielles: une phase de nécrose s'étendant sur les douze jours qui suivent la parturition et correspondant à l'élimination de la couche superficielle de la muqueuse; une phase de prolifération, allant du douzième jour après la mise-bas jusqu'à lóvulation suivante; caractérisée par le régénération progressive de la muqueuse à partir de la couche profonde restée en dehors des processus de nécrose; une phase de sécrétion et d'hypérémie qui dure pendant toute la gestation. La partie terminale de l'oviducte, formée par la confluence des deux conduits müllériens, subit les mêmes variations que l'utérus gestant. Son épithélium est tout-à-fait comparable à celui de l'utérus; son chorion, en revanche, est beaucoup plus dense et développé mais ne possède qu'une faible vascularisation.
    Notes: Summary The oviduct of Nectophrynoides occidentalis Angel, a small viviparous toad of West Africa, is divided into four parts: ostium, tube, uterus and the distal common uterine segment. Only the ostium does not show seasonal variations: it always remains transparent and is devoid of glandular cells. A ciliated epithelium lines its lumen. The tube is rectilinear, about 7–10 millimeters long and may be subdivided into four principal segments, on the basis of the chemical composition of the substances of the mucosa. Its structure is relatively simple and comparable to that of other lower vertebrates. Its appearance differs according to whether it is at rest or in activity. For most of the gestation period the tube is at rest but secretory activity starts several weeks before birth. It reaches its maximum during the days immediately preceding ovulation. Unlike the tube, the uterus undergoes continuous changes, which can be pregnant, divided into three essential phases: a phase of necrosis, extending to twelve days following birth, and corresponding to the elimination of the superficial layer of the mucosa; a phase of proliferation, extending from the twelfth day after birth until the subsequent ovulation, characterized by the progressive regeneration of the mucosa, which is initiated by the deep layer which was not involved in necrosis; a phase of secretion and hyperemia which lasts during the whole period of gestation. The terminal part of the oviduct, formed by the confluence of the two Müllerian ducts, undergoes the same variations as the uterus, its epithelium being completely comparable to that of the uterus; its chorion, however, is much denser and better developed but its vascularization is less intense.
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    Cell & tissue research 146 (1973), S. 1-14 
    ISSN: 1432-0878
    Keywords: Ventral cord ganglia ; Limulus polyphemus ; Cell types ; Neurosecretion ; Cytochemistry ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ventral cord ganglia of the horseshoe crab, Limulus polyphemus, contains six distinct cell types: three appear to be ordinary neurons and three exhibit the staining affinities of neurosecretory cells. The presumed neurosecretory cells have been termed neurosecretory cell I (NSC I), NSC II and NSC III. NSC I cells contain a colloid-like inclusion which may occur as a single small vacuole or occupy more than one-half of the cell volume. Colloid inclusions occur with greater frequency toward the periphery, although small cells of similar staining affinity occur in cords extending to the fibrous core. The histochemical tests suggest that the cytoplasm is positive for proteins, but contains no strong acidic groups which may have been derived from S-S or S-H groups. The presence of carbohydrate is also indicated. NSC II cells exhibit distinct secretory cycles. Early in the cycle the cytoplasm becomes phloxinophilic and progresses to a distinct fuchsinophilic stage. Small homogeneous irregular inclusions are found in the axon hillock during the latter stages of the cycle. Histochemical tests suggest the presence of a carbohydrate and strong acidic groups which may have been derived from S-S or S-H groups. There are small cells present which appear to be immature neurosecretory cells. NSC III cells are characterized by a perinuclear ring of cytoplasm which is stained by chrome alum hematoxylin but not by paraldehyde fuchsin. A secretory cycle may also be present in this cell type. The three cell types presumed to be ordinary neurons exhibit no particular staining affinity for the stains or tests used in this study.
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    Cell & tissue research 146 (1973), S. 261-279 
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Rat, Cat ; Motor endplate ; Reinnervation ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The formation of endplates outside the original endplate region of a muscle fibre was studied in slow and fast rat muscles. It was found that such new endplates are readily formed on the soleus muscle, whereas hardly at all in the fast extensor digitorum longus. Most new endplates appear to be morphologically normal within 2 months after nerve implantation. 2. The time course of recovery of slow and fast cat muscles was followed after crushing the sciatic nerve. It was found that the slow soleus muscle recovers more rapidly than the fast flexor hallucis longus muscle. 3. The endplates of reinnervated cat muscles are more complicated than those of the control muscles, but have nevertheless fewer nerve terminals per endplate. Reinnervated muscles are more sensitive to curare and it is suggested that this is due to a decrease in transmitter release, for it was found that less acetylcholine is released from reinnervated rat hemidiaphragms than from control ones. 4. Motor and sensory reinnervation of spindles and tendon organs was studied. At the time when motor reinnervation is almost completed the sensory endings from spindles and tendon organs are highly abnormal. Thus sensory reinnervation proceeds much more slowly than motor.
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    Cell & tissue research 147 (1974), S. 505-527 
    ISSN: 1432-0878
    Keywords: Cartilage ; Ageing ; Chondrocyte and matrix ; Light microscopy ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, histochemical, and ultrastructural investigations have been carried out on ageing costal and tracheal cartilage of rats. The following age groups of animals have been studied: 1, 7, 14, 20, 30, 45, 75 days, 6 months, and 2 years. Ageing induces cellular changes which are represented by a reduction in the number of chondrocytes, a progressive increase in glycogen deposition, and processes of degeneration, the most frequent of which is the accumulation of lipidic material within large cytoplasmic vacuoles. Changes in the intercellular matrix become evident after 20 days in costal cartilage and after 30 days in tracheal cartilage. Chondroitin sulphate decreases while keratan sulphate, whose presence is limited to the territorial matrix, increases. Glycoproteins increase slightly in young animals and then remain constant; they decrease in the subperichondrial areas in old animals. Ultrastructurally, the matrix of cartilage of young animals contains thin collagen fibrils, most of which have no periodic banding. Roundish electron dense granules are associated with these fibrils. Irregular filaments associated with small electron-dense circular bodies are present around chondrocytes as well as within cytoplasmic vacuoles. With increasing age, and coincident with the reduction of chondroitin sulphate, the thickness of collagen fibrils increases, their period becomes evident, and the associated matrix granules decrease in number and size. Areas containing these fibrils undergo calcification, which frequently starts within roundish bodies of cellular origin. Collagen fibrils with a period of 640 Å but a highly variable thickness are often present in cartilage of adult and old rats. These fibrils seem to be due to an abnormal synthetic activity of chondrocytes.
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    Cell & tissue research 147 (1974), S. 537-549 
    ISSN: 1432-0878
    Keywords: Insect haemocytes ; Classification ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A simplified insect haemocyte classification has been formulated by a light microscopic examination of the haemolymph of insects from fifteen Orders. Six cell types or developmental stages can be distinguished: (1) Prohaemocytes, (2) Plasmatocytes, (3) Granular Cells, (4) Spherule Cells, (5) Cystocytes, and (6) Oenocytoids. The structure and occurrence of these haemocytes are described together with the structural variations which occur in each cell type. Due to considerable overlap in structure and the presence of numerous intermediates the six cell types may represent different developmental and/or functional stages of one basic cell type. The available evidence for this unitarian hypothesis is discussed.
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    Cell & tissue research 149 (1974), S. 267-274 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Teleostei ; Euryhalinity ; Eta cells ; Dilatation of capillaries ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Eta cells of the pituitary of Aphanius dispar specimens adapted to sea water are densely packed and have folded nuclei. Unfolding of the nuclei accompanied by cellular hypertrophy and hyperplasia was observed 24 hours after experimental transfer of specimens into fresh water. In specimens from natural habitats and adapted over long periods to fresh water, the nuclei are rounded and cellular hypertrophy attains maximal values. Dilatation of capillaries in the hypophysis was observed in about one third of the specimens within the first few days after transfer to fresh water. In specimens adapted either to fresh water or to sea water the capillaries were normal. Epsilon cells from seawater specimens have elongated nuclei perpendicular to the basement membrane which separates the rostral neurohypophysis from the adenohypophysis; in freshwater specimens epsilon cell nuclei are rounded.
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    Cell & tissue research 151 (1974), S. 343-346 
    ISSN: 1432-0878
    Keywords: Cerebellar cortex ; Rhesus monkey, cat ; Basket cell axons ; Regional differences ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the cerebellar cortex of rhesus monkey and cat differences in the arrangement of basket cell axons and dendrites are described. In the anterior lobe, basket cell axons are short, very small in number and of a small diameter. In the posterior and nodulofloccular lobe, these fibers form plexus-like accumulations within the lower third of the molecular layer. In these parts they are longer, more numerous and bigger in diameter. Finally the contribution of Lugaro cell dendrites to this fiber accumulation is discussed.
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    Biopolymers 10 (1971), S. 1049-1057 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ultrastructural morphology and x-ray and electron diffraction of poly (Gly-Gly-Ala) have been studied. The polymer has two forms; the first, form I possesses a super-folded cross-β structure, long fibers of which show some twisting and intertwining. Form II precipitates in a less distinct fibrous form from aqueous solution. The x-ray diffraction and oriented electron diffraction data suggest that form II is a polyglycine II helix situated in a monoclinic cell with dimensions a = 8.86 Å, b = 22.0 Å, c = 9.42 Å, and β = 90°. Combined with the morphological evidence it appears likely that form II is also in an antiparallel superfolded array.
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    Biopolymers 10 (1971), S. 1099-1101 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: A statistical mechanical model was developed for use in connection with the problem of preferential binding of solvent components to proteins and of conformational transition in water-organic solvent systems. The model is a statistical one for the conformational transition of globular proteins induced by the adsorption of solutes in the solution, considered as a nearest-neighbor problem in statistical mechanics. Although a few illustrative examples are given, the actual interpretations of the experimental data using this theory are reserved for a later paper.
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    Biopolymers 10 (1971), S. 1103-1103 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
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    Biopolymers 10 (1971), S. 1121-1138 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept and representation of a logical tree as defined in computer science is applied to obtain a suitable representation of protein molecules in computer programs which handle or calculate atomic coordinates of protein molecules. On the basis of this analysis and of the analysis of the calculation and modification of the structure of a protein from bond lengths, bond angles, and dihedral angles, which is reproduced in an appendix, program modules which accomplish the various required computations are described. Three such modules are given in Iverson notation; in fact, it is hoped that this article will serve as a reasonably complete basis for the preparation of machine programs by moderately proficient programmers.
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    Biopolymers 10 (1971), S. 1207-1212 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dichroism spectrum obtained from a dilute aqueous solution of poly (ala-gly-gly) resembles that described for charged polypeptides such as the salt form of poly glutamic acid. A similar spectrum is found for films cast from aqueous solution where x-ray studies reported elsewhere have indicated a poly-glycinc II conformation. Evidence is presented for a heat induced poly-glycine II to unordered state transition similar to that described for collagen. The interpretation of this, the first observation of the optical properties of a poly-amino acid in the poly glycine II conformation, is further rationalized on the basis of spectra obtained from a number of polypeptides whose conformation approaches that of a 31 helix.
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    Biopolymers 10 (1971), S. 1229-1242 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The effect of cupric ion on the emission of tryptophan, tyrosine, and serum albumins is studied by emission spectroscopy and lifetime measurements. It is found that whenever cupric ion is bound to tryptophan or tyrosine, their emissions are quenched completely. The quenching may be due to an electron transfer mechanism. The fluorescence of complexes of cupric ions with serum albumins is partially quenched; this is because energy is transferred from tryptophan to the complexed cupric ions by a dipolar energy transfer mechanism. It is deduced from the present study that the tryptophan in the human serum albumin molecule is between 11 and 16 Å from the nearest eupric ion binding sites (assumed to be at the surface of the protein) and that one of the tryptophan in the bovine serum albumin molecule is very close to the cupric ion binding sites and the other is near the center of the bovine serum albumin molecule. It is also found that the deuterium solvent effect on serum albumin fluorescence is very small, and that the quenching of bovine serum albumin fluorescence at the N-F transition is the result of quenching of the fluorescence of both tryptophans. The phosphorescence lifetime apparatus, capable of measuring decay times of signals with intensities changing over a few orders of magnitude, and the ratio spectrofluorometer, both of which were constructed in this laboratory, are also described.
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    Biopolymers 10 (1971), S. 1253-1260 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The measurements were made for the volume and the sound velocity changes (ΔV and ΔU) on titrating the sodium salt of poly (S-carboxymethyl L-cysteine) with dilute HCl. For the reaction, —COO- + H+ → —COOH, ΔV per mole of H+ bound was + 12. 7 ml and +11. 4 ml in salt-free and 0. 2 M NaCl solutions, respectively. Corresponding ΔU was about -13 cm/sec in salt-free polymer solution where 11.5 mM carboxylate ion reacts with equimolar hydrogen ion. ΔV associated with the coil-to-β transition was found to be +2. 35 ml in H2O and +1. 90 ml in 0. 2 M NaCl per mole of amino acid residue, respectively. These values are larger than those obtained for the coil-to-helix transition of poly (L-glutamic acid). ΔU for the transition was about -30 cm/sec in salt-free solution of polymer concentration 0.0115 mole/liter. Possible sources of ΔV and ΔU for reaction; coil → β, are (1) the formation of void volume and (2) the changes in the extent of solvation in amide linkage and in side chain.
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    Biopolymers 10 (1971), S. 1317-1329 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding of three aromatic molecules to apomyoglobin has been investigated. In each case equilibrium dialysis studies and tryptophan fluorescence quenching studies indicate that a one to one complex has been formed. The fluorescence quenching studies further suggest that the binding of the aromatic molecules is at the heme site with possible involvement of the arginine CD3. Xenon, which is known to quench the fluorescence of aromatic hydrocarbons, is found to be bound to apomyoglobin-aromatic molecule complexes and quenches the emission of the aromatic molecule in the complexes. Oxygen quenches pyrene fluorescence in water solution but does not quench the pyrene fluorescence from the apomyoglobin-pyrene complex. This is explained by a slower rate of diffusion of oxygen to pyrene in the apomyoglobin-pyrene complex.
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    Biopolymers 10 (1971), S. 1365-1369 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rotor speed-dependent aggregation of T4 DNA in the analytical ultracentrifuge is studied in the presence of high pressure generated by compressed nitrogen gas in the cell. The extents of aggregation at various speeds are found to be practically the same in the presence and absence of pressure.
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    Biopolymers 10 (1971), S. 1331-1349 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The time-dependent theory developed in Part I is specialized to treat tetrameric hemoglobin, and the results of the theory for dimeric-and tetrameric hemoglobin are compared with data on the kinetics of the reactions of hemoglobin with carbon monoxide and oxygen at various salt concentrations for the case of large concentration of ligand relative to that of hemoglobin. The fit of the theoretical results to the data suggests that hemoglobin at a 2 M salt concentration is predominantly dimeric and that the tetramer should be taken as the functional unit to explain the kinetics of the reactions of normal hemoglobin. A relationship is established between the time-dependent theory arid Adair's Intermediate Compound Hypothesis (I.C.H.) for hemoglobin, as brought to its present state by Gibson and Roughton. A generalization (G.I.C.H.) of the I.C.H. is presented and is shown to be equivalent to the time-dependent theory in the limit of infinite ligand concentration. The I.C.H. is shown to be an excellent approximation to the centralized theory (G.I.C.H.) in this limit.
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    Biopolymers 10 (1971), S. 1421-1425 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
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    Biopolymers 10 (1971), S. 1427-1428 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Biopolymers 10 (1971), S. 1429-1454 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability of oligodesoxyribonucleotides of various chain lengths to form complexes has been compared with that of oligoribonucleotides. Four series of oligonucleotidcs were prepared and investigated, i.e., dCn at acid pH versus rCn, dAn and dTn versus. rAn and rUn at neutral pH. The results indicate that in dilute solution, the formation of complexes is greatly facilitated in the case of desoxyoligomers and occurs for shorter oligomere than in the corresponding ribooligomers. The spectrophotometric titration of deoxyribooligo C indicates the appearance of two pK values in the 4-5 pH region characteristic of the double-stranded form, which occurs for much shorter dCn than rCn. The circular dichroism (CD.) spectra of deoxycytidylies in dilute solution starting from the trimer are conservative, characteristic of the double-stranded helical form of poly C at acid pH. In contrast, the CD spectra of a series of corresponding ribo Cn, under identical conditions is of nonconservative character similar to that of the single-stranded form of poly C at neutral pH, but differs in the band position. This spectrum is called intermediate. Only at higher concentrations of oligonucleotidcs (i.e., 10-3Minstead of 10-4M) does the circular dichroism spectrum of longer ribocytidylics assume conservative character. Thermal denaturation of deoxycytidylces at acid pH are strongly dependent on chain length and concentration, its one would expect for a cooperative helix-coil transition. The circular dichroism spectra measured at different temperatures shows one isosbestic point. In dilute solution, the standard-state enthalpy change found was 5-6 kcal/mole for higher oligomers (dC7). These properties are all in agreement with a structural transition from the d-Cn double-stranded form to a coil for n 〉 3. Studies of dAn and dTn in solutions of high ionic strength at low temperature indicate that complex formation occurs already at the level of trimer and for high oligomers. Under identical conditions a complex between rAn and rUn is detected only for oligomers longer than the hexamer. The nature of the “intermediate” form of oligoribo C at acid pH and low temperature was investigated by sedimentation and circular dichroism. A model of rCn is proposed of linear molecules which are partially double-stranded and partially single-stranded, which probably are slowly rearranged by “slippage” into a regular-double-stranded helical form.
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    Topics: Chemistry and Pharmacology
    Notes: The number average molecular weight, Mn, of low molecular weight dextran was determined through endgroup analysis, and the intrinsic, viscosities of these materials in aqueous solution were determined at 25°C. The ultrasonic velocities in their aqueous solutions were also measured at 25 and 45°C. As concerns the molecular weight dependence of the intrinsic viscosity, partial specific compressibility of solute and the hound water around the solute, the following results were obtained. (1) log [η]-log Mn and [η]/Mn0.5 - Mn0.5 plots were in accord with the Mark-Houwink and Stockmayer-Fix-man equations respectively for Mn 〉 2, 000, but these plots deviated from the equations for Mn 〈 2, 000. (2)The partial specific compressibility, β1°, of dextran is expressed by following equation for Mn 〈 2,000: β1° = 10-12 × (13.6 log Mn - 51.7) (cm2/dyne). In contrast, it, becomes the constant value, -- 7.3 × 10-12 cm2/dyne, for Mn 〉 2,000. (3) The amount of bound water of dextran calculated from the sound velocity measurement lakes constant value of 0.17 ml g for Mn 〉 2, 000, but the amount of hydration increase with decreasing molecular weight for Mn 〈 2,000. From these results, a dextran molecule in aqueous solution is expected to change its conformation from random coiling to uncoiling stretched form at the molecular weight of around 2, 000 or about 12 glucose units.
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    Biopolymers 10 (1971), S. 1559-1581 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical rotation studies were performed on five compounds containing two peptide groups. Four of the molecules were confined to restricted regions of conformational space by the presence of closed rings. Solvent and temperature were varied, and theoretical calculations were done for each compound covering the appropriate conformational space. The interpretation which results is qualitatively successful over the conformational regions covered by the compounds. Quantitative correlation between theory and experiment will require compounds of high rigidity.
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    Biopolymers 10 (1971), S. 1617-1623 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational energy maps have been calculated for α-D-mannuronic acid (1-4) α-L-guluronic acid and for α-L-guluronic acid (1-4) β-D-mannuronic acid. These have been used, together with maps previously calculated for the homomonomeric dimers, to estimate the characteristic ratios and Kuhn lengths of the alternating copolymer and of a stochastic copolymer similar in composition to that extracted from L. digitata.The results show that the alternating copolymer is less extended than either homopolymer. Kuhn lengths calculated for the stochastic copolymer agree well with experimental results on high ionic strength solutions of alginate isolated from L digitata.
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    Biopolymers 10 (1971), S. 1635-1648 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: Poly-S-carboxyethyl-L-cysteine, a higher side-chain homolog of poly-S-carboxymethyl-L-cysteine, has been prepared from poly-S-carbobenzoxyethyl-L-cysteine with hydrogen bromide in chloroform or acetic acid. The polymer is found to be in the β-conformation of an antiparallel arrangement of polypeptide chains in solid films, both in acid and salt forms, when examined by infrared spectra. Aqueous solutions of t he polymer have been investigated by measurements of rotatory dispersion and circular dichroism as well as by infrared spectra in D2O. These properties show sharp changes around pH 5.5, as the pH of solution is varied. At higher ionization the polymer is randomly coiled, but at lower ionization it is in the β-conformation. Dependence of the rotatory properties upon polymer concentration as well as on ionic strength has been observed even at the lowest degree of ionization attained, and this has been attributed to the formation of intermolecular β-conformation in solutions. The β-structure is characterized by a negative circular dichroic band at 223 mμ and a positive dichroic band at a wavelength lower than 200 mμ, and furt her by a negative bo value, -140°. The pH-induced coil-β transition of the polymer is compared with that of poly-S-carboxymethl-L-cysteine.
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    Biopolymers 10 (1971), S. 1681-1699 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The specific heat, of rat tail tendon at various water contents was measured as a function of temperature. The resulting graphs showed peaks arising from the melting, near 50°C, of helical material in the collagen, and from the melting of absorbed water in the range -40°C to 0°C. The heat of melting of helical material was 11.7 cal per gram of dry tendon. Determination of the heat and temperature of fusion of the absorbed water allowed resolution of the water into four states in the case of tendon before denaturation, and three states after denaturation. The four states are (1) water not freezable on cooling to - 70°C, (2) freezable water with-both heat and temperature of fusion different from the values for ordinary water, (3) freezable water with the heat of fusion of ordinary water, but a different temperature of fusion, and (4) water not distinguished from ordinary water. The fourth state was absent in denatured tendon. The results are discussed in terms of increasing size of clusters of absorbed water molecules.
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    Biopolymers 10 (1971) 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Biopolymers 10 (1971), S. 1743-1757 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absorption and rotatory properties of acridine orange-poly-S-carboxymethyl-L-cysteine system in water and in 0.2 M NaCl have been measured at different pH and polymer-to-dye mixing ratios. The absorption spectra indicate that the dyes are bound to the polymer in dimeric or highly aggregated forms. At neutral pH where the polymer is randomly coiled, no optical activity is induced on the absorption bands of bound acridine orange. At acid pH where the polymer has the β-conformation, a pair of positive and negative circular dichroic bands occur at each of the absorption bands, centered around 458 and 261 mμ. The signs of those bands are opposite to those found for α-helical poly-L-glutamic acid. A model for the binding of dye to the β-form polymer is presented, in which dimeric dyes are attached to ionized carboxyl groups and slack one another to form linear arrays on both sides of an extended polypeptide chain. The observed circular dichroism spectra can be explained by the Tinoco's exciton mechanism, based on this model. Low molecular weight poly-S-carboxymethyl-L-cysteine induces quite a different circular dichroism on bound acridine orange.
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    Biopolymers 10 (1971), S. 1853-1863 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The circular dicrosim (CD) spectra of complexes of DNA with ethidiun bromnide, profiavine, 9-aminoacridine and 4-etliyl-9-amino-acridine have been determined between 220 and 450 nm, the range lieing extended to 600 nm for ethidiufm bromide. The variation of the magnitude of the visible and near - ultraviolet CD spectra of ethidium bromide - DNA complexes with the amount of ligand bound (r) suggests a common binding position with profiavine. On the other hand, 4-ethyl-9-aminoacndine complexed to DNA shows CD spectra not distinguishable from those of 9-aminnoacnidmc in both the visible and ultraviolet. The interpretation of these results with respect to the stereochemistry of the DNA-ligand complexes is discussed.
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    Biopolymers 10 (1971), S. 1901-1924 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The various treatments of sedimentation equilibrium are compared on a theoretical and an experimental basis. Particular attention is paid to the polyelectrolyte nature of the problem and the choice of a neutral component. The effective density gradients of several cesium salts for DNA are measured. Two previous theories for the effective density gradient are shown to be equivalent, and the experimental values are interpreted with respect to these theories. It is clear t hat sedimentation equilibrium in a density gradient may be used for the determination of unambiguous molecular weights.
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    Biopolymers 10 (1971), S. 1949-1972 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The theory of friction-limited DNA unwinding is developed explicitly for moderate tind large perturbations. This extension of the earlier theory of the relaxation kinetics is necessary because of the complex nature of the rate limitation for small perturbations. The assumption of the theory that is violated under relaxation conditions is that base pairing reactions occurring at a constant local degree of twist of the strands are fast compared to the net unwinding of the molecule. However, these reactions that are slow for small perturbations have a large activation energy, and become faster than friction-limited un winding for large enough temperature jumps and sufficiently large DXA molecules. Thus only the rate for moderate and large perturbations is clearly limited by frictional resistance to turning the molecule in solution. The model used is a diffusional unwinding of the two strands, driven by the accompanying decrease in free energy. For large perturbations a numerical solution of the diffusion equation is required, since the diffusion coefficient is not constant. Two new parameters must be introduced into the equilibrium statistical theory to describe friction-limited unwinding kinetics. These are the force constant b, for winding up coil regions and the frictional coefficient per base pair βcfor rotating coil regions in solution. We find by fitting the theory to experiment that b = 1.8 × 10-13 ergs/ rad2- and βc = 3.5 × 10-21 erg see/base pair, both for DNA melted in alkali at 0.4.M Na + and ∼30 °C. The latter value is in agreement with predictions based on the viscosity of single stranded DNA in alkali. The quoted value of bcan be interpreted to mean that the number of conformational states of a nucleolide is reduced by an average factor of 1.55 when it is wound around another strand to the degree of twist in a double helix, but without forming a base pair.
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    Topics: Chemistry and Pharmacology
    Notes: The properties of oligonucleotide helices of adeuylic- and uridylic acid oligomers have been investigated by measurements of hypo-and hyperchromieity. High ionic strengths favor the formation of triple helices. Thus, the double helix-coil transition can be studied (without interference by triple helices) only at low ionic-strength. A “phase diagram” is given representing the Tm-values of the various transitions at different ionic strengths for the system A(pA)17 + U(pU)17. Oligonucleolides of chain lengths 〈8 always form both double and triple helices at the nucleotide concentrations required for base pairing. For this reason the double helix-coil transition without coupling of the triple helix equilibrium can only be measured for chain lengths higher than 7. Melting curves corresponding to this transition have been determined for chain lengths 8, 9, 10, 11, 14 and 18 at different concentrations. An increase in nucleotide concentration leads to an increase in melting temperature. The shorter the chain length the lower the Tm-value and the broader the helix-coil transition. The experimental transition curves have been analysed according to a staggering zipper model with consideration of the stacking of the adeuylic acid single strands and the electrostatic repulsion of tlip phosphate charges on opposite strands. The temperature dependence of the nucleation parameter has been accounted for by a slacking factor x. The stacking factor expresses the magnitude of the stacking enthalpy. By curve fitting xwas computed to be 0.7, corresponding to a stacking enthalpy of about S kcal/mole. The model described allows the reproduction of the experimental transition curves with relatively high accuracy. In an appendix the thermodynamic parameters of the stacking equilibrium of poly A and of the helix-coil equilibria of poly A + poly U at neutral pH are calculated (ΔHA = -7.9 kcal/mole for the poly A stacking and ΔH12 = -10.9 kcal/mole for the formation of the double helix from the randomly coiled single strands). A formula for the configurational entropy of polymers derived by Flory on the basis of a liquid lattice model is adapted to calculate the stacking entropies of adenylic oligomers.
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    Biopolymers 10 (1971), S. 2049-2049 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Biopolymers 10 (1971), S. 2071-2077 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The data on the band widths and band shapes of several DNA's at various concentrations in sedimentation equilibrium in a CsCl density gradient have recently become available. In the present report, these literature data are treated in the following manner: (1) based on a theory of isotope-substitution, calculations are made of the molecular weights at infinite dilution, and (2) to explain the concentration dependence of band widths and band shapes, a theory of charge and hydration is put forth, and it is shown that by retaining the terms involving the charge of the macromolecules, it is possible to account for most of the concentration dependence.
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    Biopolymers 10 (1971), S. 2083-2094 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The mechanism of the unique and specific association of a given amino acid to its t-RNA is investigated by theoretical methods. Several possible schemes are proposed to explain specificity. The physical forces which act within these mechanisms are illustrated by the computer simulation of probable interactions between glycine and nucleotide bases and base pairs. It is demonstrated that glycine has direct and selective affinities for the nucleotide bases and that these interactions are principally determined by the polar groups. Energies have been calculated for the interaction of glycine with several base pairs. From these, the possibility that specificity arises through direct complexing of an amino acid with its anticodon is evaluated.
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    Biopolymers 10 (1971), S. 2147-2160 
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    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: Equations are developed to describe the shift in the temperature of the helix-coil transition when small molecules bind to nucleic acids. Included are high polymers, oligonucleotides, and oligomer-polymer interactions. The equations prescribe simple ways of plotting experimental data to evaluate transition and binding parameters.
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    Biopolymers 10 (1971), S. 2181-2197 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The helix-coil transitions for poly-L-lysine (PL) were investigated by the methods of spectropolarimetry, viscometry and potentiometric titration in 0.2M NaCl at different temperatures as well as in 0.2MNaBr, 1MKCl, and in mixtures of 0.2MNaCl or NaBr with methanol at room temperature. The enthalpy and entropy differences between the helical and coillike states of uncharged PL molecules in 0.2.M NaCl were determined from the potentiometric titration curves. The cooperativity parameters σ for PL in different solvents were determined by two methods (from the sharpness of the transition and from the dependence of the intrinsic viscosity on the helical content in the transition region). In 0.2MNaCl σ has a value of (2.3 ± 0.5) × 10-4 and does not depend on temperature, i.e., the cooperativity of the helix-coil transition, as for PGA, is mainly of an entropy origin (the initiating of the helical region is accompanied by the entropy decrease ΔSi = -12 eu/mole of helical regions). A comparison of the obtained results for PGA and PL with the molecular theories of the helix-coil transitions shows that the role of dipole-dipole interactions of nonneighboring peptide groups is greatly overestimated in these theories, leading to a considerable enthalpy contribution to the free energy of initiating helical regions which is not observed in the experiment.
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    Biopolymers 10 (1971), S. 2029-2037 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variation of the polarized components of fluorescence of a rodlike particle bearing a fluorescent label upon partial orientation is calculated for some special geometry of the dye macromolecules complexes. Explicit expressions are given for the case where the energy of the molecule in the field depends only on one angle θ, showing that the result is a function of both 〈sin2θ〉 and 〈sin4θ〉. For the case of orientation in an electric field through an anisotropic induced moment, the expressions allow the calculation of this anisotropy of polarizability. The method is applied to the measurement of the polarizability of rodlike fragments of DNA labeled by intercalated molecules of Acridine Orange.
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    Biopolymers 10 (1971), S. 2039-2048 
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    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As the temperature of solid poly(β-benzyl-L-aspartate) (PBLA), (CO.NH.CH.-CH2COOCH2C6H5)n, in the α-helieal form is raised from -150 °C, tlie line width and second moment of the proton magnetic resonance (PMR) signal decrease in stages until the conformational transition to the ω-helix occurs at about 90 °C. A similar temperature dependence of the PMR parameters is observed as the transformed polymer is cooled. Below -100°C (where the lattice is presumed to be rigid), the measured second moments are 9.5 Oe2 and 10.7 Oe2 for the α and ω forms, respectively. Second moments, calculated from the Van Vleck formula for the rigid lattice and also estimated for possible motional cases in which the polymer is taken to be in the ω form, are compared with the PMH data. By combination with the results of X-ray diffraction and infrared spectroscopic measurements, a tentative explanation can be made of the types of motion occurring in PBLA.
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  • 82
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    Biopolymers 10 (1971), S. 2133-2145 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have performed potentiometric titrations of poly-L-lysine. From these data we have calculated the free energy and enthalpy changes for the folding of the random coil to the α-helix in 10% ethanol (-120 and -120 cal/mole) and from the random coil to the β-structure in water (-140 and 870 cal/mole) and in 10% ethanol (-180 and 980 cal mole). Comparison of these values with each other and with values for the coil → α- helix transition in water (-78 and -880 cal/mole) led to the following conclusions. The stabilization by ethanol of ethanol of the α-helix with respect to the coil is that predicted from the known free energy of transfer of the peptide group from water to 10% ethanol. Similar data to explain the enthalpy difference are not available. The thermodynamic functions for the transition from α-helix to β-structure, obtained by subtracting those for the coil → α-helix and coil → β-structure transitions, are explained from a consideration of the structural differences: non bonded interactions of the polypeptide backbone are less favorable in the β-structure than in the α-helix, causing an increase in the energy, while hydrophobic contacts between side chains raise the entropy of the β-structure as compared with the α-helix, so that the free energy difference between the two structures is small, but enthalpy and entropy differences are large. The observation of only small differences in the free energy and enthalpy changes for the transition from coil β-structure upon going from water to 10% ethanol is expected by considering both the free energy of transfer of the peptide group (as for the α-helix) and the free energy and enthalpy of transfer of the apolar part of the side chain involved in hydrophobic bond formation.
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  • 83
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    Biopolymers 10 (1971), S. 2209-2221 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Valine specific transfer RNA (tRNAVal) was isolated from Bacillus stearothermophilus and Escherichia coli by chromatography on benzoylated DEAE-cellulose (BD-cellulose). Likewise isoleucine specific transfer RNA (tRNAIle) was isolated from B. stearothermophilus and from Mycoplasma sp. Kid. The thermal denaturation profiles (melting curves) of the two tRNAVal species in the presence of Mg+ + were nearly identical. However, the Tm for the Kid tRNAIle was about 10°C lower than that for the B. stearothermophilus tRNAIle. A nuclease and tRNA-free aminoacyl-tRNA synthetase (AA-tRNA synthetase) preparation from B. stearothermophilus was able to function efficiently at temperatures up to 80°C in the aminoacylation of all four tRNA species. Determination of the amino acid-acceptor activity of each tRNA species as a function of temperature of the aminoacylation reaction showed in each case a strong correlation between the loss of acceptor activity and the thermal denaturation profile of the tRNA. Evidence is presented that the loss in acceptor activity is most likely due to a change in structure of the tRNA as opposed to denaturation of the enzyme. These results further support the idea that correct secondary and/or tertiary structure must be maintained for tRNA to be active as a substrate for the AA-tRNA synthetase.
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  • 84
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    Biopolymers 10 (1971), S. 2275-2281 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Cotton effects of N-acetoacetyl amino acids and derivatives were examined by a circular dichroism technique. A correlation has been established between the sign of the Cotton effect and the absolute configuration of the asymmetric center. The L derivatives show, in dioxane, negative circular dichroism curves, whereas the D antipodes present positive curves. The effect of solvent and pH and influence of alkylation at the amide nitrogen are also discussed.
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  • 85
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    Biopolymers 10 (1971), S. 2345-2358 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The anisotropy of electrical polarizability of rodlike fragments of DNA has been studied by a number of electro-optical methods: Kerr effect (combined with flow birefringence), light scattering, diehroism, and fluorescence in an electric field. The most sensitive technique (Kerr effect) has been used to study the variation of the polarizability with the nature and concentration of counteroins. DNA fragments constitute a truly rigid polyelectrolyte of known structure. The value obtained can then be quantitatively compared to the predictions of those of the theories of the longitudinal polarizability of rigid polyelectrolytes which are based on true molecular parameters. The comparison emphasizes the role of the counterion-counterion repulsion. Oosawa's theory seems to represent the best approach but fails to explain the differences observed between monovalent and divalent ions.
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  • 86
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    Biopolymers 10 (1971) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 87
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    Biopolymers 9 (1970), S. 811-824 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The root-mean-square end-to-end distance has been calculated for a model allowing free rotation about glycoside bonds for the general case of polysaccharides having a disaccharide repeating unit. Numerical estimates are given for several naturally occurring structures based on an idealized pyranose unit in the C1 chair conformation. Extrapolation procedures which make use of the intrinsic viscosity [η] in good solvents to obtain unperturbed dimensions do not represent, data for hyaluronic acid very well, especially at low molecular weights. However, order-of-magnitude estimates suggest that this polymer behaves similarly to other polysaccharides, and probably has stiffer local structure than typical non-ionic synthetic polymers. A double logarithmic plot of the product of [η] and M̄w, the weight-average molecular weight, against the degree of polymerization in the range for M̄w of 104 to 2 × 104 permits a straight-line fit of available data for all the glycosaminoglycans, including heparin and the chondroitin sulfates, as well as sodium carboxymethyl cellulose. This result suggests similarity of short-chain hydrodynamic behavior of these polymers.
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  • 88
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    Biopolymers 9 (1970), S. 875-875 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Biopolymers 9 (1970) 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Biopolymers 9 (1970), S. 865-874 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A common approximation for deriving solutions to the Lamm equation is to neglect diffusion. This paper presents a singular perturbation technique that allows one to estimate the band spreading due to nonzero diffusion coefficient. We illustrate the general mathematical technique by its application to sedimentation when pressure effects are important. Comparison of the approximate solution with accurate numerical solutions shows that the relative errors are of the order of 1% both for concentration and concentration gradient for parameters of chemical interest.
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  • 91
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    Biopolymers 9 (1970), S. 891-896 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glycogen acquires a negative charge in both alkaline and acidic solutions and can move in an electrical field, its mobility being related to the degree of alkalinity or acidity. There is a slight increase in relative viscosity at both ends of the pH spectrum. These effects and the changes in nuclear magnetic resonance as a function of pH are interpreted.
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  • 92
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The viscosity of bovine liver glutamate dehydrogenase solutions was studied at 10 and 20° C in 0.2.M sodium phosphate buffer at pH 7, in the concentration range 0.1-8 mg/ml. A method for the study of the viscosity of very dilute solutions of associating enzymes is described. It was found that the reduced specific viscosity ηsp/c of glutamate dehydrogenase continuously increases with increasing enzyme concentration, from about 4 ml/g at the lowest concentrations to about 16 ml/g at 8 mg/ml. In the presence of 10-3M GTP and 10-3M NADH the viscosity increase is much smaller and the results can be extrapolated to zero enzyme concentration to yield an intrinsic viscosity [η] = 3.2. The values of ηsp/c in phosphate buffer alone apparently extrapolate to the same value of [η], or to a value close to it. We also observe that, in the presence of toluene ηsp/c increases very much more with enzyme concentration: ηsp/c already equals 16 ml/g at a concentration of 0.75 mg/ml. These observations are in good agreement with the hypothesis that the active oligomer of glutamate dehydrogenase (MW = 312,000) associates with increasing enzyme concentration to form linear rodlike polymers of indefinite length. This association is strongly diminished by the addition of 10-3M GTP, 10-3M NADH. Toluene, on the other hand, promotes reversible association to linear polymers of very high molecular weight. The transverse and axial rotary frictional coefficients of macroscopic bodies, similar to a physical model for the structure of glutamate dehydrogenase recently advanced, were determined. Assuming that the viscosity of the model is equal to that of an ellipsoid of rotation with identical frictional coefficients, we calculate [η] = 3.26 ml/g according to Kuhn and 3.20 ml/g according to Simha, for the glutamate dehydrogenase oligomer, in good agreement with the result derived from the study of enzyme solutions.
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  • 93
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    Biopolymers 9 (1970), S. 911-922 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular monolaycrs of poly(β-benzyl L-aspartate) spread at. an air-water interface have been studied. The results obtained both by direct observations on the monlayer and from examination of collapsed films with polarized infrared spectroscopy and electron diffraction are consistent with the presence of right handed α-helices in the mono-layer when the molecular weight is high. When 1% (v/v) isopropanol is present in the subphase the right-handed helix prevails, provided that the monolayer is first spread on water. Monolayers of low molecular weight polymer appear to form the crossed-β structure. Orientated collapsed films of high molecular weight polymer can be converted to the left-handed α-helical and to the ω-conformation, and the mechanisms are discussed. The surface chemistry of this polymer is compared with that of related polymers and a consistent pattern of behavior emerges.
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  • 94
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    Biopolymers 10 (1971), S. 2537-2553 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The MCD (magnetic circular dichroism) spectra of Ap, ApA, ApApA, poly A, Up, UpU, poly U and double-stranded poly A:U alternating copoly A-U and alternating deoxyribopoly A-T were measured with a Cary 61 spectropolarimeter fitted with a Varian superconducting magnet at a field strength of 50 Kgauss. The MCD spectra of T2 and T5 DNA at various stages of heal denaturation were measured as a function of hyperchromicity of the sample. MCD spectra of the intact and degraded T2 and T5 phages were used to study the degree of alteration of the DNA inside the phages versus the DNA in vitro. The results for the adenine polymers show that the main MCD bands, B2u(271 nm), B1u(252 nm), and E1u(212 nm), show a decrease in specific magnitude as the length of the polymer is increased, reflecting the degree of stacking of the polymer. In contrast, the uridine series of polymers shows little change of the MCD bands, indicating that there is little interaction between the bases regardless of the length of the polymers. The MCD spectra of poly A:U, alternating poly r(A-U): (A-U), and alternating poly d(A-T):(A-T) show significant differences among themselves in the magnitude of the B2u band and when compared with the sum of the spectrum for the poly A plus poly U. This may indicate the selective effect of hydrogen bonding on the B2u band. Alternatively, the difference may be due to the absence of an n → π* transition in the double-stranded polymer. Measurements of denatured T2 and To DNA's show increases in all MCD bands. The T2 DNA internally packed in phage shows an increase of the B2u and E1ubands, the B2u remaining unchanged. The internal T5 DNA shows an increase of the B1u band only. Thus, the internal DNA structure is altered in a manner quite different from a simple denaturation caused by hydrogen bond breaking. Furthermore, different MCD bands indicate that different modes of DNA packing exist for T2 and T5 phages.
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  • 95
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    Biopolymers 10 (1971), S. 2591-2596 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The infrared absorption of poly-L-proline in concentrated aqueous salt solutions was measured in the fundamental region. Of primary interest were the carbonyl absorption of the peptide linkage and the methylene C-H bending absorption of the pyrrolidine ring. These spectral regions each show an additional component in the concentrated salt solutions. Using the position of the absorptions of poly-L-proline I (cis) and II (trans) as models, we conclude that both cis-trans linkages are present in the peptide in salt solutions. Increasing the temperature shifts the equilibrium slightly in favor of cis.
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  • 96
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    Biopolymers 10 (1971), S. 2619-2621 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 97
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    Biopolymers 10 (1971), S. 2635-2638 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 98
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 99
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simplified scheme for treating the spatial configurations of polynucleotide chains is developed using the rotational isomeric state approximation and statistical methods applicable to linear systems of interacting subunits. As a consequence of geometric constraints imposed by the skeletal structure and of the severity of certain steric interactions, it is possible to represent the repeat unit comprising six skeletal bonds by two virtual bonds of fixed length. The configuration of the polynucleotide chain as a whole may be conveniently described by an alternating succession of these two virtual bonds. Moreover, analysis of steric interactions suggests that bond rotations governing the mutual orientation of a given pair of successive virtual bonds should be sensibly independent of the rotations affecting the mutual orientation of other pairs. The statistical mechanical treatment of configuration-dependent properties is much simplified in consequence of this mutual independence. Mean-square dimensions calculated by giving equal weights to all sterically allowed conformations are much smaller than values determined by Felsenfeld and co-workers. The calculated dimensions are markedly increased, however, by placing certain arbitrary restrictions on the rotations about selected pairs of skeletal bonds. It is thus demonstrated that steric interactions alone are insufficient to account for the spatial characteristics of polynucleotide chains. The dimensions are also found to be sensitive to the conformation of the ribose ring of each nucleotide unit, but, insofar as the influences of steric interactions are concerned, the dimensions do not depend on the heterocyclic base attached to the ribose ring.
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  • 100
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    Biopolymers 11 (1972), S. 119-126 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A theory is presented concerning the possible arrangements of protomers in tetrameric molecules. Isoenzymes may exist even in the case of homotetramers if the asymmetry of the identical protomers is detectable. The number of tetrahedral isoenzymes that can be isolated depends on the nature of the intersubunit bonds and on the level of the asymmetry of the protomers. Five isoenzymes can be distinguished only if two different types of protomers form tetrahedral tetramers and the asymmetry of protomers is not detectable with the method used. If the two types of protomers can bind each other by any pairs of binding sets and the asymmetry of both protomer types reaches the level of detection with the method used, we obtain 117 isoenzymes: 15 individual ones, and 51 stereoisomeric pairs.
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