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  • Articles  (1,236)
  • Cell & Developmental Biology  (1,084)
  • Bone  (152)
  • 1970-1974  (1,112)
  • 1915-1919
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  • Articles  (1,236)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 15 (1974), S. 111-123 
    ISSN: 1432-0827
    Keywords: Fluoride ; Calcium ; Phosphorus ; Bone ; Periosteum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une méthode d'estimation de la surface périostée de l'os en voie de minéralisation est mise au point et appliquée à des porcs recevant 2 mg de fluorure par Kg de poids et par jour pendant 10 mois. L'adjonction de fluor intervient significativement dans le cas d'une déficience en calcium et phosphore. La surface en voie de minéralisation est nettement réduite. Lorsque le calcium et phosphore sont normaux, l'addition de fluorure augmente nettement la surface en voie de minéralisation. Le microscope électronique à balayage permet de mettre en évidence au niveau de l'os une perte de l'orientation longitudinale des fibers et des surfaces poreuses irrégulières chez les animaux soumis au floor.
    Abstract: Zusammenfassung Zur Bestimmung der verkalkenden Oberfläche des Periosts wurde eine Methode entwickelt und bei Schweinen angewandt, welche während etwa 10 Monaten 2 mg Fluorid per kg Körpergewicht und per Tag erhalten hatten. Dieses zusätzliche Fluorid hatte eine signifikante Wirkung bei Calcium- und Phosphormangel. Die verkalkende Oberfläuche ging stark zurück, während jedoch, wenn kein Calcium- und Phosphormangel bestand, das zusätzliche Fluorid die verkalkende Oberfläche vergrößerte. Beobachtungen mit dem Raster-Elektronenmikroskop am Knochen zeigten, daß die Längsorientierung der Fasern fehlte und daß Knochen von mit Fluorid gefütterten Tieren unregelmäßige, poröse Oberflächen aufwiesen.
    Notes: Abstract A method for estimating periosteal bone-mineralizing surface was developed and applied to swine fed 2 mg of fluoride/kg of body weight/day for about 10 months. Added fluoride interacted significantly with calcium and phosphorus deficiency. Mineralizing surface was greatly reduced, whereas when calcium and phosphorus were adequate, added fluoride greatly increased mineralizing surface. Scanning electron microscope observations of bone disclosed loss of longitudinal orientation of fibers and irregular porous surfaces in bone from fluoride-fed animals.
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  • 2
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    Calcified tissue international 15 (1974), S. 125-132 
    ISSN: 1432-0827
    Keywords: Bone ; Collagen ; Formic Acid ; Crosslinkages ; Cyanogen Bromide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bovine and chicken bone collagens have been solubilized and presumably denatured (gelatin) by treatment of demineralized, powdered tissue with 70% formic acid. Short periods of extraction such as four hours at 30°, conditions commonly used during cyanogen bromide cleavage of collagen, solubilized 50% and 15% of the chicken and bovine bone collagens respectively. Treatment of the tissues with sodium borohydride partially inhibited the extraction of collagen from chicken bone, but had little effect on the extraction of calf bone collagen. The heterogeneity of the bone gelatin from both species on disc electrophoretic analysis suggested that peptide bonds had been cleaved in some of the collagen chains during exposure to formic acid, thus facilitating the solubilization of the bone collagen as the gelatin. Analysis of the collagen extracted from chicken bone for reducible crosslinks indicated that a large proportion of these bonds had remained intact, in contrast to a previous finding that most of these crosslinks were destroyed in bone gelatin extracted by 4 M CaCl2, at pH 7.0. The stability of the major reducible crosslinks in bone collagen to severe acid conditions may explain in part some of its unique properties, such as its failure to swell or be solubilized in dilute acid, which distinguish it from soft tissue collagens.
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  • 3
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    Calcified tissue international 15 (1974), S. 173-179 
    ISSN: 1432-0827
    Keywords: Bone ; Strength ; Tension ; Compression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A simple method is described for visualising regions of bone that have yielded in tension. The appearance of such regions is quite different from that of regions that have yielded in compression. The significance of these findings is discussed.
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  • 4
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    Calcified tissue international 15 (1974), S. 189-199 
    ISSN: 1432-0827
    Keywords: Bone ; Densitometry ; X-ray ; Radiation ; Specific gravity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract X-ray and γ-radiation techniques for evaluating bone density under field conditions in cattle and sheep were investigated. The best results were obtained from measurements of the density of radiographs of tibial tarsal bones of sheep and from the absorption of γ-radiation of the tibial tarsal bones of sheep and the fibular tarsal bones of cattle. The γ-radiation techniques may be carried out rapidly under field conditions (up to 30 animals an hour) and bone density can be estimated with a standard error of 0.042–0.046 SG units.
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  • 5
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    Calcified tissue international 16 (1974), S. 169-182 
    ISSN: 1432-0827
    Keywords: Histochemistry ; Alkaline phosphatases ; Calcification ; Bone ; Teeth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Activity of alkaline phosphatases in unfixed cold microtome setions from the lower first molar area of newborn mice was recorded by histochemical methods. A substrate specificity test included the following phosphate compounds: ATP, CTP, GTP, UTP, ADP, AMP, GP, PPi, MDP and naphthol AS-TR phosphate. Intense staining was obtained in osteoblasts, stratum intermedium of the enamel organ and odontoblasts with all the substrates, except PPi and MDP. Staining of skeletal muscle fibres was obtained only with triphosphates as substrates. Addition of-SH groups decreased the hydrolysis of triphosphate compounds in cells involved in mineralization while the hydrolysis of monophosphate was inhibited. In contrast triphosphatase activity in striated muscle was enhanced when-SH compounds were added. Demineralization with EDTA diminished the cytoplasmic staining but induced a nuclear staining in hard tissue forming cells when triphosphates were used as substrates. No cytoplasmic and only slight nuclear staining was seen with GP or AMP as substrates. The triphosphate hydrolyzing capacity of tongue muscle fibres was, however, increased after the decalcification treatment. Addition of Mg2+ ions to the incubation media distinctly lowered the hydrolysis of triphosphates in the investigated tissues whereas the hydrolysis of ADP, AMP, GP and naphthol AS-TR phosphate remained unchanged. In view of the findings the triphosphatase activities at alkaline pH of muscle fibres and of cells related to hard tissue formation are considered to be due to activity of separate enzymes. The orthophosphate liberating enzyme activities at alkaline pH in osteoblasts, stratum intermedium and odontoblasts may be expressions of the catalytic functions of one common enzyme. Furthermore, the results indicate that CaATP might be the substrate used by the alkaline ATPase in mineralizing areas.
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  • 6
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    Calcified tissue international 16 (1974), S. 239-250 
    ISSN: 1432-0827
    Keywords: EHDP ; Bone ; Collagen ; Histology ; Bone chemical analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The purpose of this study was to determine the short-term effects of various systemic doses of disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) on bone organic matrix and to relate these effects to the corresponding dose-related changes in bone mineral. EHDP was administered daily by subcutaneous injection at doses of 0.25, 2.5 and 40 mg/kg body weight for periods of one and two weeks. At both time intervals, rat tibiae were quantitatively analyzed for mineral content (ash, calcium and phosphorus) and for organic matrix content (matrix weight, nitrogen and certain amino acids). The latter data were correlated with semiquantitative histological analyses of the tibiae. Results of this study demonstrate that the short term effects of EHDP on bone chemistry and histology are variable and depend on the systemic dose and the duration of treatment. Systemic doses of 0.25 and 2.5 mg/kg EHDP following daily administration for one week resulted in transitory decreases in bone mineral content compared to controls. Following two weeks of treatment, both of these dose levels resulted in increased bone mineral content and, in addition, the 2.5 mg/kg dose resulted in tibiae which contained more organic matrix compared to control bones. In contrast to the low dose effects, a high systemic dose of EHDP—e.g. 40 mg/kg administered daily for 1 or 2 weeks—appears to act solely by inhibiting mineralization of newly-formed matrix.
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  • 7
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    Calcified tissue international 16 (1974), S. 335-338 
    ISSN: 1432-0827
    Keywords: Fluoride ; Plasma ; Bone ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Fluoride analyses were carried out on blood samples from fasting subjects and on iliac crest biopsies obtained at autopsy, using an ion-selective electrode. Correlation coefficients of 0.53 and 0.67 respectively were determined between plasma fluoride and age, and bone fluoride and age. The proportionate rates of increase of fluoride levels in plasma and bone with age and the similarity of the correlation coefficients suggest that the fasting plasma fluoride concentration is in equilibrium with bone fluoride.
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  • 8
    ISSN: 1432-0827
    Keywords: Osteogenesis ; Osteoinduction ; Bone ; Matrix ; Cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone matrix demineralized in 0.6 N HCl at 2° for 24 h and implanted in muscle in allogeneic rats possesses consistently reproducible bone morphogenetic activity. Experiments on implants of matrix, obtained from donors injected with3H-tyrosine or3H-tryptophan, or Na35SO4, suggest that bone morphogenetic property is a protein or apart of a protein that is (1) insoluble in buffer solutions, pH 3.6 and 5.0; (2) degraded in buffer solutions at pH 7.4 by an endogenous sulfhydryl-group neutral proteinase; (3) digested by trypsin at 15° within 8 h without solubilization of the helical regions, possibly even without degradation of the nonhelical ends of the bone collagen molecule, and without any loss of the periodic ultrastructure of the collagen fibrils; (4) degraded or removed by 0.1 N NaOH at 2° within 24 h without solubilization of collagen; (5) biologically active even after nitration of tyrosyl groups with tetranitromethane. The release of only one-third of the radioactivity with loss of nearly all yield of new bone by limited tryptic digestion of3H-borohydride-reduced matrix indicates that the bone morphogenetic response is the function of a non-collagenous component. Autoradiographs of implants of matrix with non-collagenous proteins labelled with3H-tryptophan,3H-tyrosine, or both3H-tyrosine and3H-phenyl-alanine demonstrate random dissemination of the radioactive constituents and no evidence of local transfer of labelled proteins or soluble protein derivatives. Hypothetically, the bone morphogenetic response is controlled by an insoluble acidic bone morphogenetic protein or polypeptide (BMP) and a soluble neutral proteinase (BMP-ase) resembling trypsin in activity except functionally more specific for BMP. Firmly bound but separable from bone collagen, BMP is one of many short-lived morphogenetic substances appearing and disappearing throughout embryonic development and persisting in postfetal life. Where the BMP receptor resides and how it activates cell mechanisms of differential repression and derepression of such genes as code for osteogenesis is unknown.
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  • 9
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    Calcified tissue international 14 (1974), S. 153-160 
    ISSN: 1432-0827
    Keywords: Lysosomes ; Bone ; Resorption ; Osteoclast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des techniques histochimiques de microscope photonique et électronique montrent que les ostéoclastes métaphysaires chez des rats “sans incisive” présentent des quantités plus importantes de phosphatase acide, d'acryl sulfatase et de trimétaphosphatase acide lysosomiales. L'activité en phosphatase lysosomiale à pH neutre est aussi plus élevée dans les ostéoclastes métaphysaires, sauf dans les cellules situées sous la métaphyse, où l'enzyme est absente. L'absence de résorption de la matrice organique semble en rapport avec l'absence de bordures en brosse et une absence d'enzyme lysosomiale extracellulaire. Malgré cette absence, une dissolution de cristaux inorganiques a été mise en évidence au microscope électronique, suggérant que la dissolution minérale est un processus distinct de la désintégration enzymatique de la matrice organique.
    Abstract: Zusammenfassung Histochemische Techniken für Licht- und Elektronenmikroskopie zeigten, daß metaphysäre Osteoklasten “Schneidezahl-loser” (SL) Ratten erhöhte Mengen von lysosomaler saurer Phosphatase, von Arylsulfatase und von saurer Trimetaphosphatase enthielten. Die Aktivität der lysosomalen Phosphatase bei neutralem pH war in den metaphysären Osteoklasten ebenfalls erhöht, außer in den Zellen direkt unterhalb der Wachstumsplatte, wo dieses Enzym nicht vorkam. Es konnte überhaupt keine Resorption der organischen Matrix festgestellt werden, was übereinzustimmen schien mit der Abwesenheit eines gekräuselten Saumes und einer gleichzeitigen Abwesenheit des extrazellulären lysosomalen Enzyms. Trotzdem wurde im Elektronenmikroskop das Verschwinden anorganischer Kristalle festgestellt, was darauf schließen läßt, daß die Auflösung des Minerals nicht derselbe Vorgang ist wie die enzymatische Auflösung der organischen Matrix.
    Notes: Abstract Histochemical techniques for light and electron microscopy showed that metaphyseal osteoclasts in “incisors absent” rats contained greater than normal amounts of lysosomal acid phosphatase, aryl sulfatase and acid trimetaphosphatase. Lysosomal phosphatase activity at neutral pH was also elevated in the metaphyseal osteoclasts except in those cells immediately beneath the growth plate, where this enzyme was absent. The failure of any discernable resorption of organic matrix appeared to correlate with the absence of a ruffled border and a concomittant absence of extracellular lysosomal enzyme. Despite this failure, electron microscopic evidence of inorganic crystal removal was noted, suggesting that mineral dissolution represents a separate process from the enzymatic breakdown of organic matrix.
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  • 10
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    Calcified tissue international 16 (1974), S. 13-36 
    ISSN: 1432-0827
    Keywords: Osteoclast ; Bone ; Resorption ; Crystals ; Organic-inorganic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The organic-inorganic relationships in bone matrix undergoing osteoclastic resorption have been studied in rat tibial diaphyses using electron microscope techniques in an attempt to identify the steps of the resorption process. Results suggest that bone resorption occurs in two phases: the first, an extracellular phase, leads to bone matrix fragmentation and partial dissolution, and the second, an intracellular phase, to complete digestion of the breakdown products of the bone matrix. The first component of the bone matrix to be attacked by the osteoclast is the ground substance. This induces the release of the crystals lying between, and on, the collagen fibrils; any crystals lying within fibrils are released later, when the fibrils break up. As this stage proceeds, the collagen fibrils retain their normal intrinsic texture, but gradually loose their lateral aggregation, appearing as individual fibrils (some of them uncovered by crystals), mixed with fragments of fibrils and many free crystals. The loosened but otherwise structurally normal collagen fibrils, and their fragments, are strongly argyrophilic. Complete dissolution of the disaggregated fibrils occurs outside the cell, both in the resorption zone and in the initial portion of the channels of the ruffled border. The free crystals present in the resorption zone and those phagocytosed in cytoplasmic vacuoles are organic-inorganic structures, whose organic component (the crystal ghost) is, at least in part, of proteoglycan nature. Dissolution of inorganic material occurs within the cytoplasmic vacuoles of the osteoclasts. Results are viewed in relation to the process of bone resorption and, as far as crystal ghosts are concerned, to that of bone calcification. A tentative summary of the various steps involved in the mechanism of bone resorption is given.
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  • 11
    ISSN: 1432-0827
    Keywords: Bone ; Parathyroid ; 25-Hydroxycholecalciferol ; Adenosine 3′, 5′ cyclic monophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Phenytoin, at a concentration which is known to inhibit parathyroid extract-induced bone resorptionin vitro, has been shown to have no significant effect on either the cyclic AMP content of four-day-old mouse calvaria which had been in tissue culture for 48 h or on the increase in cyclic AMP content occurring after the addition of parathyroid extract to the medium. Phenytoin has also been shown to be an effective inhibitor of bone resorptionin vitro induced by 25-hydroxycholecalciferol. These observations suggest that the inhibitory effect of phenytoin on parathyroid extract and hormone-induced bone resorption takes place beyond the cyclic AMP stage.
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  • 12
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    Calcified tissue international 16 (1974), S. 219-226 
    ISSN: 1432-0827
    Keywords: Bone ; Phosphate ; ATP ; Calcium ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract An active constituent of the leaves ofSolanum malacoxylon (SM) is shown to promote calcium resorption and citrate production in embryonic chick frontal bone culturedin vitro. When injected into rats, SM reduces the ATP content of liver and kidneys. This phenomenon may be related to the ability of SM to stimulate mitochondrial ATPase activity at pH 9.4. SM significantly reduces the concentration of phosphate necessary to alter the uptake of calcium and respiration of siolated mitochondria. The data suggest that SM influences calcium and phosphate metabolism by affecting ion movements into and out of mitochondria.
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  • 13
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    Calcified tissue international 14 (1974), S. 283-289 
    ISSN: 1432-0827
    Keywords: Sodium fluoride ; Osteoporosis ; Bone ; Strength ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'utilisation thérapeutique de fluorure de sodium a été recommandée dans le traitement de diverses maladies osseuses ostéopéniques. Cet emploi est basé principalement sur les effects ostéosclérotiques bien connus du fluorure de sodium, mais on connait mal son effet sur la force de résistance osseuse. L'influence de diverses concentrations de fluorure de sodium sur la force de résistance osseuse de jeunes rats soumis à des régimes riches et pauvres en calcium a été étudiée. L'administration de fluorure de sodium augmente le diamètre osseux, indiquant une stimulation de la formation de l'os périosté, mais la force de résistance osseuse est réduite ou non modifiée par l'ingestion de fluor.
    Abstract: Zusammenfassung Die therapeutische Verwendung von Natriumfluorid ist für eine Anzahl von Knochenmangel-Krankheiten empfohlen worden. Die Empfehlungen basieren hauptsächlich auf den bekannten osteosklerotischen Wirkungen von Natriumfluorid; über dessen Effekt auf die Knochenstärke ist wenig bekannt. In dieser Arbeit wurde der Einfluß verschiedener Konzentrationen von Natriumfluorid auf die Knochenstärken von wachsenden Ratten mit hoher und niederer Calciumeinnahme untersucht. Die Verabreichung von Natriumfluorid erhöhte den Knochendurchmesser, was auf eine Stimulierung der Periostbildung hinwies, die Knochenstärke wurde jedoch durch Fluorideinnahme herabgesetzt oder nicht beeinflußt.
    Notes: Abstract The therapeutic use of sodium fluoride has been recommended in a variety of osteopenic bone diseases. The recommendations are based mainly on the known osteosclerotic effects of sodium fluoride and little information is available as to its effect on bone strength. The influence of various concentrations of sodium fluoride on bone strength in growing rats on high and low calcium diets was studied. The administration of sodium fluoride increased bone diameter, indicating stimulation of periosteal bone formation, but bone strength was reduced or not affected by fluoride ingestion.
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  • 14
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    Calcified tissue international 14 (1974), S. 291-299 
    ISSN: 1432-0827
    Keywords: Bone ; Collagenase ; Lysozyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Du lysozyme de blanc d'œuf, ainsi que des protéines basiques, telles que de l'histone et une base dépourvue de protamine, semblent inhiber la collagénase osseuse de souris. L'inhibition de collagénase osseuse de souris par le lysozyme est mise en évidence lorsque l'activité de la collagénase est étudiée en utilisant du collagène comme substrat à l'état solide, mais non lorsque le collagène est utilisé en solution. D'autre part, l'inhibition de l'activité en collagénase par l'histone et une base dépourvue de protamine est observée dans les deux systèmes. L'inhibition de collagénase ossuese de souris par des molécules polyanioniques est intéressante, étant donné que des travaux antérieurs ont montré que plusieurs molécules polyanioniques telles que l'héparine, le sulfate de dextrane et l'acide polyethylenesulfonique augmentent l'activité de collagénase osseuse de souris dans les mêmes conditions expérimentales. Comme le lysozyme est largement présent dans les tissus conjonctifs et que sa concentration carie avec l'ampleur du remaniement tissulaire, l'inhibition de la collagénase osseuse de souris suggère un role éventuel dans la régulation de la dégradation du collagène, pendant le remaniement des tissus collagéniquesin vivo au cours d'états normaux et pathologiques.
    Abstract: Zusammenfassung Lysozyme aus Hühnereiweiß sowie Basis-Proteine, wie z. B. Histon und Protamin-freie Basen, erwiesen sich als Hemmer der Mäuseknochen-Kollagenase. Diese Hemmung durch Lysozym wurde festgestellt, wenn für die Messung der Kollagenase-Aktivität Kollagen in Substanz als Substrat verwendet wurde, nicht aber, wenn das Substrat aus gelöstem Kollagen bestand. Andererseits wurde die Hemmung der Kollagenase-Aktivität durch Histon und Protamin-freie Basen in beiden Versuchssystemen festgestellt. Die Hemmung von Mäuseknochen-Kollagenase durch polykationische Moleküle ist interessant, vor allem im Hinblick auf frühere Feststellungen, daß mehrere polyanionische Moleküle, wie Heparin, Dextransulfat und Polyaethylensulfonsäure, die Aktivität der Mäuseknochen-Kollagenase unter denselben experimentellen Bedingungen erhöhen. Da Lysozym in Bindegeweben überall verteilt ist und da dessen Konzentration mit der Neubildungsrate des Gewebes variiert, läßt die Hemmung der Mäuseknochen-Kollagenase durch Lysozym dessen mögliche Rolle in der Regulierung des Kollagenabbaues vermuten, und zwar während der Neubildung von Kollagengeweben in vivo in normalen und pathologischen Zuständen.
    Notes: Abstract Egg white lysozyme, as well as basic proteins such as histone and protamine-free base, were found to inhibit mouse bone collagenase. The inhibition of mouse bone collagenase by lysozyme was detected when the activity of the collagenase was assayed using collagen as the substrate in the solid state, but not when the collagenase activity was assayed using collagen in solution as the substrate. On the other hand, the inhibition of collagenase activity by histone and protamine-free base was observed in both assay systems. The inhibition of mouse bone collagenase by polycationic molecules is interesting in light of previous findings that several polyanionic molecules, such as heparin, dextran sulfate and polyethylenesulphonic acid, enhance the activity of mouse bone collagenase under the same experimental conditions. Since lysozyme is widely distributed in connective tissues and its concentration varies with the rate of tissue remodeling, the inhibition of mouse bone collagenase by lysozyme suggests its possible role in the regulation of collagen degradation during the remodeling of collagenous tissuesin vivo during normal and pathological states.
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  • 15
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    Calcified tissue international 14 (1974), S. 309-315 
    ISSN: 1432-0827
    Keywords: Osteoblast ; Matrix ; Bone ; Scanning electron microscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les territoires sécrétoires des ostéoblastes d'os pariétal de rats sont déterminées en utilisant la microscopie électronique à balayage. Le territoire moyen de 4.620 cellules, dans 19 territoires, est de 154 μm2 par ostéoblaste. Les valeurs extrêmes par champ varient de 136 à 177 μm2 par ostéoblaste. Quatre cent cellules sont mesurées individuellement; la valeur moyenne par ostéoblaste est de 143 μm3 avec une déviation standard de 33. Le taux d'apposition journalier, mesuré par la tétracycline pendant 8 jours, est de 3.12 μm (déviation standard 0.22). Ce qui correspond à une production matricielle journalière d'environ 470 μm3 par ostéoblaste.
    Abstract: Zusammenfassung Die Ausscheidungsbereiche von Ratten-Osteoblasten des Scheitelbeines wurden mit dem Raster-Elektronenmikroskop direkt gemessen. Der durchschnittliche Bereich von 4620 Zellen in 19 Gesichtsfeldern war 154 μm2 per osteoblast. Der Streubereich lag in den verschiedenen Gesichtsfeldern zwischen 136 und 177 μm2 per Osteoblast. 400 Zellen wurden einzeln gemessen. Bei diesen war der Durchschnittswert per Osteoblast 143 μm2, mit einer Standard-Abweichung von 33. Die tägliche Anlagerungsrate während einer Periode von 8 Tagen war 3,12 μm (Standard-Abweichung 0,22); sie wurde mittels Tetracyclinmarkierung der Mineralisierungsfront gemessen. Dies ergab eine tägliche Produktionsrate der Matrix von etwa 470 μm3 per Osteoblast.
    Notes: Abstract The secretory territories of rat osteoblasts on the parietal bone were measured directly using scanning electron microscopy. The mean territory of 4620 cells in 19 fields was 154 μm2 per osteoblast. The range for the fields was 136 to 177 μm2 per osteoblast. Four hundred cells were measured individually—for these the mean value per osteoblast was 143 μm2 with a standard deviation of 33. The daily rate of apposition over an 8 day period was 3.12 μm (standard deviation 0.22) measured by tetracycline marking of the mineral front. This gave a daily matrix production rate of approximately 470 μm3 per osteoblast.
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  • 16
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    Calcified tissue international 14 (1974), S. 327-331 
    ISSN: 1432-0827
    Keywords: Bone ; Piezoelectricity ; Collagen ; Aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The piezoelectric constant of mature and immature bone (defined herein) has been measured in an effort to determine whether it varies with age. It was found that the average value of the piezoelectric constantd 14 of femur from three week old calves was 58% of the value of femur from three year old bulls. The results were interpreted to indicate qualitative differences in the corresponding collagen matrices. Mature human tibia from males ranging in age from 21 to 53 years of age showed a small but significant increase ind 14 with age. Some data concerning diseased human bone, and well-preserved human bone excavated in Peru are also presented.
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  • 17
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    Calcified tissue international 14 (1974), S. 333-337 
    ISSN: 1432-0827
    Keywords: Bone ; Materials ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des métaux poreux et des céramiques sont implantés dans l'osin vivo et sont prélevés, après différents intervalles, pour étudier histologiquement la colonisation tissulaire. Les implants prélevés sont fixés avec les tissus environnants et inclus dans des epoxy-résines, de faible viscosité. Les échantillons sont coupés à l'aide d'une scie diamantée et fixés sur des lames pétrographiques, pour être ensuite amincis à environ 75 μm. Ils sont légèrement colorés au bleu de méthylène et à l'alizarine rouge S, qui donne un bon contraste entre tissus durs et mous et démontrent la présence d'os calcifié dans les implants poreux métalliques et céramiques.
    Abstract: Zusammenfassung Poröse Metall- und Keramikstücke wurden in vivo in Knochen implantiert und nach verschiedenen Intervallen entnommen, um histologisch zu untersuchen, wie weit sie ins Gewebe eingewachsen waren. Die entnommenen Implantate mit dem sie umgebenden Gewebe wurden fixiert, dehydriert und in ein niedrigvisköses Epoxy-Harz eingebettet. Die Proben wurden mit einer Diamantsäge in dicke Schnitte zerteilt, auf Steinscheiben zementiert und von Hand auf etwa 75 μm geschliffen. Sie wurden mit Methylenblau und Alizarin-Rot S schwach gefärbt; dies ergibt einen großen Kontrast zwischen Knochen und Weichgewebe und zeigt die Bildung von verkalktem Knochen innerhalb poröser Metall- und Keramik-Implantate deutlich.
    Notes: Abstract Porous metals and ceramics were implanted in bonein vivo and retrieved at intervals for histological evaluation of tissue ingrowth. Recovered implants with surrounding tissues were fixed, dehydrated and embedded in a low-viscosity epoxy resin embedding medium. The embedded samples were cut into thick sections with a diamond saw, cemented to petrographic slides, and hand-ground to approximately 75 μm. They were lightly stained with methylene blue and Alizarin Red S, which provided great contrast between the bone and soft tissues, and clearly demonstrated the formation of calcified bone within porous metal and ceramic implants.
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  • 18
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    Calcified tissue international 15 (1974), S. 11-20 
    ISSN: 1432-0827
    Keywords: Bone ; Growth ; Resorption ; Caudal ; Vertebra ; Fluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une méthode de mesure de l'apposition et de la résorption osseuse est mise au point au niveau de la septième vertèbre caudale de jeunes rats, pesant 25–90 g, pendant la période de croissance. Cette pièce osseuse a des avantages certains par rapport à d'autres localisations, car elle est symétrique en coupe transversale et non affectée par des forces corticales. En utilisant trois marqueurs d'os différents, fluorescents en lumière ultra-violette, administrés à des intervalles de 3, 5 ou 7 jours, les modifications de croissance sont observées sur des coupes transversales centrales, non décalcifiées, de la septième vertèbre caudale. Une formation osseuse linéaire se développe à une vitesse moyenne de 10.0 μ/jour et une résorption linéaire de 6.1μ/jour est notée. Pendant la période de croissance observée, la formation osseuse s'observe exclusivement à la surface du périoste et la résorption se fait le long de la surface de l'endoste. A ce niveau l'os est totalement résorbé, chez des animaux de 25 g en 22–26 jours. Il semble que chez des animaux plus âgés, une formation osseuse endostée se développe rendant alors impossible toute étude prolongée dans cette région.
    Abstract: Zusammenfassung Es wird eine Methode zur Messung der Knochenbildungs- und Resorptionsgeschwindigkeiten im siebten Caudalwirbel junger Ratten während ihrer Wachstumsperiode von 25–90 g beschrieben. Dieser Knochen hat gegenüber jenen, die vorgängig untersucht wurden, den großen Vorteil, in transversalen Schnitten symmetrisch und unbeeinflußt von kortikalen Unregelmäßigkeiten zu sein. Die Art der Wachstumsveränderungen wurden an nichtentkalkten zentralen Transversalschnitten der siebten Caudalwirbeln bestimmt; dazu wurden drei verschiedene, farbige, im UVbereich fluoreszierende Knochenmarkierungssubstanzen verabreicht und zwar in 3-, 5- oder 7tägigen Intervallen. Die lineare Knochenbildung fand mit einer mittleren Geschwindigkeit von 10,0 μ pro Tag statt, die lineare Knochenresorption mit einer solchen von 6,1 μ pro Tag. Während der untersuchten Wachstumsperiode fand die Knochenbildung ausschließlich an der Periostoberfläche und die Knochenresportion an der endostalen Oberfläche statt. Der Knochen, der beim 25 g schweren Tier an diesem Ort vorlag, verschwand durch die endostale Resorption innerhalb von 22–26 Tagen
    Notes: Abstract A method for measuring bone formation and resorption rates in the seventh caudal vertebra of young rats during the growth period from 25–90 g is reported. This bone site has unique advantages over those previously studied, being symmetrical in transverse section and uncomplicated by cortical drift. Utilising three different coloured ultraviolet fluorescent bone labelling substances administered at either 3, 5 or 7 day intervals, the nature of growth changes was determined from undecalcified central transverse sections of the seventh caudal vertebrae. Linear bone formation occurred at a mean rate of 10.0 μ/day and linear bone resorption at 6.1 μ/day. During the growth period studied, bone formation occurred exclusively on the periosteal surface and bone resorption on the endosteal surface. Bone existing in this site in 25 g animals was completely removed by endosteal resorption within 22–26 days. Evidence exists that in older rats endosteal bone formation occurs and renders the site unsuitable for long term studies.
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    Calcified tissue international 15 (1974), S. 45-54 
    ISSN: 1432-0827
    Keywords: Bone ; Fluoride ; Microhardness ; Mineralization ; Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Microhardness was measured in sampling sites in the tibial diaphysis of control rats that received less than 1 ppm fluoride in the drinking water, and experimental rats that received 30, 90 and 120 ppm fluoride in the drinking water for 17 days. The latter dose was toxic, as evidenced by a decreased final body weight in this group. By means of tetracycline labelling, it was possible to measure bone hardness in four zones of increasing bone age: I) 3 days, II) 8 days, III) 13 days and IV) 22 days. Zones I through III represented bone formed during fluoride treatment, and Zone IV bone formed before fluoride treatment. In the control group, microhardness increased from Zone I to II, probably because mineral concentration was relatively low in Zone I, and remained constant thereafter. In the 90 and 120 ppm fluoride-treated groups, maximum microhardness was not achieved until Zone III. This delay was probably due to the fact that fluoride in large doses inhibits the rate of mineralization. In the 30 ppm fluoride-treated group, there was no delay in achievement of maximum microhardness; microhardness values in Zones I and III were greater than those in control animals, and microhardness in Zone III was higher than that in Zone IV. These results show that: 1) bone microhardness is increased in bone formed during fluoride treatment in rats given 30 ppm fluoride in the drinking water, 2) toxic doses of fluoride delay, but do not prevent achievement of normal maximum microhardness, and 3) changes in microhardness are seen only in bone formed during fluoride treatment.
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  • 20
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    Calcified tissue international 15 (1974), S. 71-76 
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Deficiency ; Osteoporosis ; Species
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    Topics: Biology , Medicine , Physics
    Notes: Abstract 21-day-old rats and mice were fed a low-calcium diet (0.02% Ca) or a normal diet (0.5% Ca) for two weeks. Administration of the low-calcium diet resulted in greater decreases in femur ash content and serum calcium in rats than in mice. Microscopic examination revealed that metatarsal bones from a majority of the rats fed a low-calcium diet displayed moderate or severe osteoporotic changes whereas bones from mice were either normal or displayed only slight osteoporotic changes under the same experimental conditions. These results indicate that mice are better able to adapt to a low-calcium diet than are rats of the same age.
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  • 21
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    Calcified tissue international 15 (1974), S. 315-324 
    ISSN: 1432-0827
    Keywords: Bone ; Mineral ; Osteogenesis ; Interference microscopy
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    Notes: Abstract A method based on tetracycline labeling was developed for selecting, in frozen sections of fetal mouse femur, bone foci approximately 6, 24, 48 and 72 h of age. Microinterferometric measurements of these foci permitted a calculation of the effective thickness (t) and refractive index (n) of each focus. After demineralizing the sections by a method which left the organic portion of the bone intact, the foci were re-measured andt andn of the organic compartment of each focus were determined;t andn of the mineral compartment were calculated by difference. A sharp decrease and subsequent rise in then of whole bone occurred between 6 and 48 h. These changes derived from the mineral compartment, and were thought to have resulted from the formation of amorphous calcium phosphate and hydroxyapatite, respectively. The mineral present in 6 h foci, however, was believed to be some precursor of amorphous calcium phosphate.
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  • 22
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    Calcified tissue international 15 (1974), S. 329-332 
    ISSN: 1432-0827
    Keywords: Microradiography ; Bone ; X-ray
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    Topics: Biology , Medicine , Physics
    Notes: Abstract A low cost, self-contained, commercially available, X-ray apparatus which possesses the essential qualifications necessary to produce high resolution microradiographs of undecalcified bone is described. The widespread current use of this machine in pathology laboratories may make purchase of such a unit optional.
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  • 23
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    Calcified tissue international 16 (1974), S. 73-88 
    ISSN: 1432-0827
    Keywords: Dentine ; Bone ; Histocytochemistry ; Physiological Calcification
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    Notes: Abstract Histochemical methods were used to detect differences in amino acid reactive groups between bone and osteoid, dentine and predentine. Three major differences were found: Predentine and osteoid contained more reactive sulphydryls than their mineralized counterparts. The greatest reaction for this reactive group was obtained at the mineralizing front. Dentine and bone contained a complex between amino and carboxylic acid groups; predentine and osteoid did not have this complex and carboxylic acid residues were less in these tissues. Dentine and bone contained much greater amounts of histidine or a histidine-like component than did predentine and osteoid. It is proposed that these differences are involved in initiation of mineralization.
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    Calcified tissue international 16 (1974), S. 261-275 
    ISSN: 1432-0827
    Keywords: Dentine ; Bone ; Mineralization ; Density gradient fractionation ; Proteoglycans
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    Topics: Biology , Medicine , Physics
    Notes: Abstract In order to obtain enough material to analyse the organic matrix of mineralizing tissue a technique for preparative separation according to the degree of mineralization was developed. The method employs ultracentrifugation of powdered material in density gradients made from acetone and bromoform. The density range of the fractions is checked by refractive index measurements of the gradient medium. The amount of the material in the fractions is checked by weighing and their degree of mineralization is estimated by determining the Ca/N and P/N ratios. The homogeneity of the fractions is determined by soft X-ray microscopy. Isolated dissected microscopic bone structure (osteones and lamellar bone fragments) with different degrees of mineralization were fractionated in this way. Chromatography on Sepharose 2B of proteoglycans from costal cartilage exposed to an acetone-bromoform gradient revealed no effect of the gradient medium on the molecular size of the proteoglycans.
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  • 25
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    Calcified tissue international 14 (1974), S. 161-168 
    ISSN: 1432-0827
    Keywords: Diphosphonates ; Osteoid Synthesis ; Hydroxyproline ; Bone ; Formation-Resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Deux diphosphonates, à savoir l'éthane-1-hydroxy-1,1-diphosphonate (EHDP) et le dichlorométhane diphosphonate (Cl2MDP), inhibentin vitro la résorption osseuse qui est stimulée soit par la parathormone ou par voie intrinsèque dans un système de culture d'os en remaniement. Alors que le Cl2MDP est plus efficace que l'EHDP dans l'inhibition de la résorption, ce fait semble en rapport avec une diminution de le formation de tissu ostéoide. Il s'en suit une diminution biochimique et morphologique marquée du remaniement osseux avec le Cl2MDP à une concentration équivalent à 10 μg de phosphore/ml de milieu de culture. La différence d'activité entre l'EHDP et le Cl2MDP peu être liée à leur affinité relative pour les surfaces du minéral osseux et, par suite, à leur concentration effective dans la fluide extracellulaire osseux. Les diphosphonates pourraient aussi affecter l'os indirectement si l'on admet que le degré de minéralisation de la matrice est important pour l'induction et la régulation de l'activité ostéoblastique dans l'os en voie de remaniement.
    Abstract: Zusammenfassung Zwei Diphosphonate, Aethan-1-hydroxy-1,1-diphosphonat (EHDP) und Dichloromethylen-Diphosphonat (Cl2MDP) hemmen in vitro die Knochenresorption. Diese wird verfolgt entweder mittels Stimulierung durch PH oder in einem Kultursystem, in welchem normale Knochenneubildung stattfindet. Während Cl2MDP die Resorption wirksamer hemmt als EHDP, scheint es ebenfalls eine Verminderung der Osteoidbildung zu verursachen. Dies bewirkt eine deutliche biochemische und morphologische Herabsetzung der Knochenneubildung, bei einer Cl2MDP-Konzentration von 10 μg Phosphor/ml Kulturmedium. Die unterschiedliche Wirksamkeit von EHDP und Cl2MDP läßt sich wahrscheinlich auf ihre verschiedenen Affinitäten zu der Oberfläche des Knochenminerals und somit auf ihre tatsächliche freie Konzentration in der extracellulären Flüssigkeit des Knochens zurückführen. Ausgehend von der Annahme, daß die Anregung und Regulierung der Osteoblasten-Aktivität bei der Knochenneubildung vom Ausmaß der Matrix-Mineralisation bestimmt wird, läßt sich die Vermutung aufstellen, daß die Diphosphonate die Knochenbildung auch indirekt beeinflussen können.
    Notes: Abstract Two Diphosphonates, ethane-1-hydroxy-1,1-diphosphonate (EHDP) and dichloromethylene diphosphonate (Cl2MDP) inhibitin vitro bone resorption, which is either stimulated by parathyroid hormone or intrinsic in a bone remodeling culture system. While Cl2MDP is more effective than EHDP in inhibiting resorption, it also appears to result in a related diminution in osteoid formation. This effect causes a marked biochemical and morphological depression of bone remodelling with Cl2MDP at a concentration equivalent to 10-μg-phosphorus/ml of culture medium. The difference in activity between EHDP and Cl2MDP may be related to their relative affinities for the bone mineral surfaces and hence their effective free concentration in the bone extracellular fluid. It is hypothesized that diphosphonates may also affect bone formation indirectly if one assumes that the degree of mineralization of the matrix is important in the induction and regulation of osteoblastic activity in remodelling bone.
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    Calcified tissue international 14 (1974), S. 195-210 
    ISSN: 1432-0827
    Keywords: Bone ; Fossil bone ; Bone resorption ; Boring channels ; Fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'action ostéoclasique exercée par un champignon appartenant au genreMucor sur des os inhumés a été étudiée au point de vue morphologique. L'érosion ossuse donne lieu à des cavités et à des canalicules de percement, dont les parois apparaissent régulièrement calcifiées jusqu'a l'interface avec le champignon, ce qui veut dire que la réabsorption intéresse en même temps la matrice organique et les cristallites. Au contraire des ostéoclastes, la membrane du champignon ne montre jamais un bord en brosse au niveau des points où elle se met en contact avec le tissu osseux. De même l'examen au microscope électronique ne décele apparemment aucun passage de matériel dans l'épaisseur de la membrane ainsi que dans le protoplasme du champignon, ce qui porte à admettre qu'un processus de solubilisation a lieu au préalable. Seulement dans le cas où le champignon présente des phénomènes de vieillissement, des données font prévoir la libération d'une substance capable de décalcifier la matrice organique. Tous les résultats ci-dessu sont discutés de façon analytique et comparés à ceux fournis par les canalicules de percement des os fossiles.
    Abstract: Zusammenfassung Die osteoklastische Aktivität eines der Mucor-Gattung angehörenden Pilzes auf begrabene Knochen wurde morphologisch untersucht. Die Wirkung dieses Pilzes in der Knochenerosion führt zu Resorptionshöhlen und Bohrkanälen, deren Wände scharf und bis zur Oberfläche gut verkalkt sind; das bedeutet, daß die Knochenresorption gleichzeitig die Kristalliten und die organische Matrix in Mitleidenschaft zieht. Im Gegensatz zu den normalen Osteoklasten zeigt die Membran des Pilzes an den Berührungsstellen mit dem Knochengewebe keinen Bürstensaum. Ebenfalls läßt eine elektronenmikroskopische Untersuchung keinen Durchgang von Substanzen durch die Membran und das Protoplasma des Pilzes erkennen, so daß man annehmen muß, daß vorher ein Auflösungsprozeß stattgefunden hat. Die Vermutung liegt nahe, daß eine Substanz, welche den anorganischen Knochenanteil aufzulösen vermag, sich
    Notes: Abstract A morphological investigation has been carried out on the osteoclastic activity revealed by a fungus of theMucor genus on buried bone. The hallmark of its activity in eroding bone is the finding of resorption pits and boring channels whose walls are sharp and well calcified up to the free edge, suggesting that bone resorption affects crystallites and the organic matrix simultaneously. Unlike normal osteoclastic cells, the fungal membrane in contact with the bone shows no brush border. As the electron microscope reveals no migration of material to the fungal membrane and its protoplasm, the view is expressed that the material which reaches the fungus has been previously solubilized. There is good reason for supposing that a substance capable of solubilizing the inorganic bone fraction spreads freely through bone tissue, decalcifying the matrix, where, but only where, hyphae show the effects of ageing. All the findings are thoroughly discussed and compared with those furnished by the boring channels in fossil bone.
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    Calcified tissue international 14 (1974), S. 245-249 
    ISSN: 1432-0827
    Keywords: Bone ; Repair ; Histology ; Implant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Um modèle expérimental, destiné à l'étude de la cicatrisation osseuse, est mis au point. Il permet d'obtenir du tissu osseux pour des études qualitatives et quantitatives. Des tubes de nylon sont implantés dans l'alvéole d'incisives extraites de cobayes. Une étude histologique de coupes longitudinales montrent que les implants de nylon ne retardent pas la cicatrisation des lésions osseuses et contiennent suffisamment de tissus pour des études biochimiques.
    Abstract: Zusammenfassung Es wurde ein Modellsystem zum Studium der Knochenwiederherstellung entwickelt, mit Hilfe dessen man von dem sich wiederbildenden Knochengewebe Proben für die qualitative und quantitative Bestimmung entnehmen kann. Dazu wurden in die Alveolen extrahierter Schneidezähne von Meerschweinchen Nylonschläuchlein eingelegt. Die histologische Untersuchung von Längsschnitten zeigte, daß die Nylonimplantate den Wiederherstellungsprozeß des Knochendefektes nicht verzögerten, daß sie herauspräpariert werden konnten und genügend Gewebe enthielten, um für biochemische Untersuchungen verwendet zu werden.
    Notes: Abstract A model system for the study of bone repair has been developed which allows the recovery of repairing osseous tissue for qualitative and quantitative evaluation. Nylon tubes were implanted in the alveoli of extracted incisors in guinea pigs. A histological study of longitudinal sections showed that the nylon implants did not delay the reparative processes of the bony defect, could be dissected out and contained sufficient tissue to be used in biochemical studies.
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    Calcified tissue international 14 (1974), S. 251-255 
    ISSN: 1432-0827
    Keywords: Cartilage ; Bone ; Vitamin A ; Phosphatases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Au cours d'une étude du cartilage épiphysaire de poulets normaux et déficients en vitamine A, la composition organique et l'activité phosphatasique du cartilage au repos, du cartilage en voie d'ossification et de l'os nouvellement formé ont été mesurées. Le cartilage en voie d'ossification et l'os nouvellement formé ont un contenu plus élevé en matériel inorganique, phosphate et collagène que le cartilage au repos. Une déficience en vitamine A provoque une augmentation du contenu en phospholipide de tous les trois tissus. Le cartilage au repos, en cas de déficience en vitamine A, présente, après homogénéisation et centrifugation, un surnageant dont l'activité en phosphatase alcaline et en glycérophosphatase est plus élevée que celle des témoins. Il semble que les effets enzymatiques de l'avitaminose A soient liés à des altérations de la membrane lysosomiale avec décharge de phosphatases. La minéralisation normale semble aussi faire intervenir une activité phosphatasique.
    Abstract: Zusammenfassung Diese Arbeit beschreibt Untersuchungen des Epiphysenknorpels bei normalen Küken und solchen mit Vitamin-A-Mangel. Die organische Zusammensetzung und die Phosphatase-Aktivität in ruhendem Knorpel, ossifizierendem Knorpel und neugebildetem Knochen wurden gemessen. Der ossifizierende Knorpel und der neugebildete Knochen hatten einen höheren Gehalt an anorganischem Material, an Phosphat und Kollagen als der ruhende Knorpel. Vitamin-A-Mangel führte zu einem erhöhten Phospholipidgehalt in allen drei Geweben. Nach Homogenisierung und Zentrifugierung fand sich im Überstand des ruhenden Knorpels von Vitamin-A-Mangelgewebe eine höhere alkalische Phosphatase- und Glycero-phosphatase-Aktivität als bei den Kontrollen. Es wird angenommen, daß die Wirkung des Vitamin A-Mangels auf die Enzyme im Zusammenhang steht mit der Schädigung der lysosomalen Membran, wobei Phosphatasen freigesetzt werden, und daß die normale Mineralisierung die Phosphatasen-Aktivität ebenfalls anregt.
    Notes: Abstract This paper reports studies of the epiphyseal cartilage in normal and vitamin A deficient chicks. The organic composition and the phosphatase activity in the resting cartilage, ossifying cartilage and new bone were measured. The ossifying cartilage and new bone had a higher content of inorganic material, phosphate and collagen than the resting cartilage. Vitamin A deficiency caused increase in the phospholipid content of all three tissues. The resting cartilage from vitamin A deficient tissue had, after homogenisation and centrifugation, a supernatant with an activity of alkaline phosphatase and glycerophosphatase higher than that in control samples. It is considered that effects of vitamin A deficiency on enzymes are related to defects of the lysosomal membrane with release of phosphatases, and that normal mineralisation also involves phosphatases activity.
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    Calcified tissue international 15 (1974), S. 181-188 
    ISSN: 1432-0827
    Keywords: Biopsy ; Bone ; Calcium ; Phosphorus ; Specific gravity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The specific gravities (SG) of bone samples taken from various parts of the skeleton of cattle and sheep were determined gravimetrically in an effort to establish which sites give the most reproducible and uniform results, so that between animals, or sequential within animals, comparisons may be made with maximum sensitivity. Samples obtained from the mandible of sheep and the rib of cattle and sheep were found to be too variable to be useful for most purposes. Best results were obtained using whole bones which are easily prepared, such as the tibial tarsal bones of cattle and sheep and the fibular tarsal bone of cattle. These bones gave within animal deviations of 0.012–0.024 SG units, when comparing left bone with right bone. Slightly higher values were obtained for coccygeal vertebrae from cattle and distal metacarpal condyles from sheep. SG was related to ash, calcium and phosphorus contents of coccygeal vertebrae of cattle and it is considered that, for survey work on the mineral status of the bones of cattle and sheep, the correlations are sufficiently high to make their determination unnecessary. This will enable radiation determined SG techniques to be applied to this type of work.
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    Calcified tissue international 14 (1974), S. 31-48 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Calcification ; Collagen ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une méthode pour l'étude de la croissance des os longs de foetus de rat, en culture d'organe, dans un milieu chimiquement défini, a été mise au point. Les extrémités cartilagineuses et les parties centrales de l'os sont analysées séparément pour leur croissance et minéralisation en étudiant leur contenu en collagène, calcium et phosphate, poids sec, et incorporation de proline marquée en hydroxyproline. La croissance et la minéralisation des parties centrales osseuses sont plus lentes dans un milieu chimiquement défini qu'in vivo. La croissance peut être accélérée en ajoutant au milieu des acides aminés non essentiels, de l'albumine ou du sérum. Les extrémités cartilagineuses présentent une augmentation plus importante en poids et contenu en collagène que les parties centrales et l'adjonction de diverses substances a moins d'effet sur la croissance. La croissance et la minéralisation des parties centrales sont augmentées en élevant la concentration du milieu en phosphate de 1.5 à 4.5 mM, avec ou sans adjonction de sérum ou d'albumine. A une concentration faible de calcium (0.5 mM), la croissance et la minéralisation des parties centrales sont arrêtées. A une concentration faible en magnésium (0.5 mM), la minéralisation est augmentée, mais la croissance est arrêtée.
    Abstract: Zusammenfassung Es wird eine Methode beschrieben, mit welcher das Wachstum der Röhrenknochen von Rattenembryos in einem chemisch bestimmten Medium in Organkultur untersucht werden kann. Die Knorpelenden und Knochenschäfte wurden gesondert auf Wachstum und Mineralisation geprüft, indem Collagen-, Calcium- und Phosphatgehalt, das Trockengewicht und der Einbau von markiertem Prolin in Hydroxyprolin gemessen wurden. Wachstum und Mineralisation des Knochenschaftes waren langsamer in einem chemisch bestimmten Medium als in vivo. Das Wachstum konnte beschleunigt werden, indem dem Medium nicht-essentielle Aminosäuren, Albumin oder Serum beigegeben wurden. Die Knorpelenden zeigten eine viel stärkere Zunahme an Gewicht und Collagengehalt als die Schäfte, und Anreicherung des Mediums hatte weniger Wirkung auf ihr Wachstum. Das Wachstum und die Mineralisation der Knochenschäfte nahmen zu, wenn die Phosphatkonzentration im Medium zwischen 1,5 und 4,5 mM erhöht wurde, und zwar unabhängig davon, ob dem Medium Serum oder Albumin beigegeben wurde oder nicht. Bei niederer Calciumkonzentration (0,5 mM) im Medium wurden Wachstum und Mineralisation der Knochenschäfte beeinträchtigt. Bei niedriger Magnesiumkonzentration (0,5 mM) wurden die Mineralisation erhöht, das Wachstum hingegen gehemmt.
    Notes: Abstract A method for studying the growth of fetal rat long bones in a chemically defined medium in organ culture is described. Cartilage ends and bone shafts were analyzed separately for growth and mineralization by measuring the collagen, calcium, and phosphate content, dry weight, and incorporation of labeled proline into hydroxyproline. Growth and mineralization of the bone shaft were slower in a chemically defined medium thanin vivo. Growth could be enhanced by supplementation of the medium with non-essential amino acids, albumin or serum. Cartilage ends showed a greater increase in weight and collagen content than the shafts, and medium supplements had less effect on their growth. Bone shaft growth and mineralization were enhanced by increasing medium phosphate concentration over a range of 1.5 to 4.5 mM whether or not the medium was supplemented with serum or albumin. At a low medium calcium concentration (0.5 mM) bone shaft growth and mineralization were impaired. At a low magnesium concentration (0.5 mM) mineralization was enhanced, but growth was impaired.
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    Calcified tissue international 14 (1974), S. 83-86 
    ISSN: 1432-0827
    Keywords: Bone ; Reproductive cycle ; Pigeons ; Amorphous ; Crystalline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une étude de diffraction aux rayons X, au cours du cycle de ponte d'oeufs de pigeon, a été entreprise pour évaluer les modifications de la proportion entre les phases de phosphate de calcium amorphe et apatitique. La partie médullaire du fémur de pigeon est totalement résorbée au cours du cycle de reproduction. Au cours de ce processus, l'os contenant plus de phosphate de calcium amorphe est résorbé avant celui qui est riche en cristaux. Ainsi l'os à contenu amorphe plus élevé est métaboliquement plus actif que l'os riche en cristaux. L'os médullaire qui peut être induit chez le pigeon mâle par traitement aux oestrogènes, ressemble, au point de vue diffraction aux rayons X, à l'os médullaire des femelles au début du cycle de reproduction.
    Abstract: Zusammenfassung Mittels Röntgen-Diffraktion wurden die Veränderungen in den prozentualen Mengen der amorphen und der kristallinen Calciumphosphat-Phasen im Femur der Taube während des Eierlegens untersucht. Der medulläre Teil des Taubenfemur wird während des Fortpflanzungscyclus vollständig resorbiert. Dabei wird der Teil des Knochens, der mehr amorphes Calciumphosphat enthält, vor dem kristallreichen Teil resorbiert. Daraus folgt, daß der Stoffwechsel des Knochens mit höherem amorphem Gehalt aktiver ist als derjenige des Knochens mit höherem kristallinem Gehalt. Weiter konnte mittels Röntgendiffraktion festgestellt werden, daß der medulläre Knochen, welcher in männlichen Tauben durch Oestrogenbehandlung erzeugt werden kann, dem weiblichen medullären Knochen am Anfang des Fortpflanzungscyclus gleicht.
    Notes: Abstract This is an X-ray diffraction study of the changes in the proportional amounts of the amorphous and apatitic calcium phosphate phases in pigeon femur during the egg-laying cycle. The medullary portion of pigeon femur is completely resorbed in the reproductive cycle. In this process the portion of bone which is higher in amorphous calcium phosphate is resorbed before the crystal-rich portion. Thus, bone with a higher amorphous content is more metabolically active than more crystalline bone. Finally, medullary bone which can be produced in male pigeons by estrogen treatment was found by X-ray diffraction to resemble female medullary bone at the beginning of the reproductive cycle.
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    Calcified tissue international 14 (1974), S. 49-58 
    ISSN: 1432-0827
    Keywords: Glycosaminoglycans ; Intracellular ; Chondrocytes ; Cartilage ; Embryonal ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les glycosaminoglycanes acides de chondrocytes isolés, en suspension, sont étudiés. La matrice extracellulaire est isolée par traitement successif à la trypsine et à la collagénase d'os d'embryons de poulet, âges de 15 à 17 jours. Après digestion à la papaïne et élimination des acides nucléïques par traitement à la DNAse et à la RNAse, les glycosaminoglycanes sont précipités par le CPC et isolés sous la forme de leur sel sodique. Les analyses des propriétés de solubilité du CP glycosaminoglycane par le microfractionnement d'Antonopoulos et coll. (1964) révèlent la présence de glycosaminoglycanes intracellulaires de poids moléculaire et/ou de densité de charge nettement plus faibles que ceux de la matrice extracellulaire. Sur des électrophorèses de microzones, une petite partie des glycosaminoglycanes intracellulaires isolées présente une mobilité similaire à celle des solutions témoins de sulfate de chondroitine, alors que la portion la plus importante ne se déplace qu'à mi-distance de l'acide hyaluronique et montre une large trainée, indiquant une faible charge négative. Ce fait semble dû à une perte de l'influence de régulation des composants matriciels éliminées, sur la synthèse des glycosaminoglycanes et au rejet dans le milieu de glycosaminoglycanes initialement synthétisé. Pour la première fois, une faible quantité d'acide hyaluronique intracellulaire est mise en évidence par une mobilité électrophorétique typique.
    Abstract: Zusammenfassung Saure Glykosaminoglycane von isolierten Chondrocyten in Suspension wurden untersucht, und die extracelluläre Matrix von 15–17 Tage alten Knochen von Kükenembryos wurde durch die aneinanderfolgende Behandlung mit Trypsin und Collagenase erhalten. Nach der Papain-Verdauung und Beseitigung der Nucleinsäuren mittels DNS- und RNSase-Behandlung wurden die Glykosaminoglycane mit CPC gefällt und als Natriumsalz isoliert. Untersuchungen der Löslichkeit der CP-Glykosaminoglycane mittels des Mikrofraktionierungsverfahrens von Antonopouloset al. (1964) zeigten intracelluläre Glykosaminoglycane mit meist niedrigerem Molekulargewicht und/oder niedrigerer Ladungsdichte als diejenigen der extracellulären Matrix. In der Mikro-Zonen-Elektrophorese zeigte nur ein kleiner Teil der isolierten intracellulären Glykosaminoglycane eine Mobilität, die dem Standard des Chondroitinsulfats entsprach. Der größte Teil legte nur die halbe Distanz der Hyaluronsäure zurück und zeigte breites “Tailing”, was auf eine niedrigere negative Ladung hindeutet. Die Ursache dafür wurde interpretiert als Verlust eines regulierenden Einflusses der entfernten Matrixkomponenten auf die Glykosaminoglycan-Synthese und als Abgabe ursprünglich synthetisierter Glykosaminoglycane in das Medium. Es wurde erstmals, anhand der typischen elektrophoretischen Beweglichkeit, eine kleine Menge von intracellulärer Hyaluronsäure nachgewiesen.
    Notes: Abstract Acid glycosaminoglycans were studied from isolated chondrocytes in suspension and the extracellular matrix obtained by sequential trypsin and collagenase treatment of 15- to 17-day-old embryonic chick bone. After papain digestion and removal of the nucleic acids by treatment with DNAse and RNAse, the glycosaminoglycans were precipitated by CPC and isolated as their sodium salt. Analyses of the CP-glycosaminoglycan solubility properties with the microfractionation procedure of Antonopouloset al. (1964) showed intracellular glycosaminoglycans of predominantly lower molecular weight and/or charge density than those of extracellular matrix. On micro-zone electrophoresis, only a minor part of the isolated intracellular glycosaminoglycans showed a mobility similar to that of the chondroitin sulphate standards while the major part moved only half the distance of hyaluronic acid and showed broad tailing, indicating a low negative charge. This was considered to be due to loss of a regulatory influence of the removed matrix components upon glycosaminoglycan synthesis and to release of originally synthesized glycosaminoglycans into the medium. For the first time, a small amount of intracellular hyaluronic acid was shown by typical electrophoretic mobility.
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    Calcified tissue international 15 (1974), S. 333-339 
    ISSN: 1432-0827
    Keywords: Vitamin D ; Bone ; Resorption ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A series of analogues of vitamin D have been tested for their ability to stimulate bone resorption in two test systems used previously to investigate the metabolites of vitamine D. These analogues were tested (a) by directly comparing their action on bone explants of mouse half-calvariain vitro, and (b) by injecting them into young mice and measuring the degree of resorptionin vitro when explants were prepared 18 hours after the injection. It is concluded that the key functional groups concerned with enhancing the activity of vitamin D3 are the 1α- and the 25-hydroxyl,both together; the cis ring structure for ring A appears necessary. 1α-Hydroxycholecalciferol (1α-OHD3) is about as active as 25-OHD3 in the direct test, but its potency is much nearer to that of 1,25-(OH)2D3 when tested by the second (indirect) method; it seems likely that 1α-OHD3 is converted into 1,25-(OH)2D3 in vivo. The results are discussed in relation to the designing of analogues for clinical and experimental use.
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    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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    Calcified tissue international 16 (1974), S. 305-313 
    ISSN: 1432-0827
    Keywords: Osteosarcoma ; Lyophilization ; Induction ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone formation was induced by iso- and home-implantation of lyophilized mouse osteosarcoma, in which an osteogenic activity is observed. The inducing factor is present exclusively in osteosarcoma, such as BF and Gardner, while not in non-osteogenic tumors, such as Ehrlich ascites tumor (2N & 4N) or mouse mammary carcinoma. The production of bone was rapid and extensive. It usually occurred within 21 days, and the time required for osteogenesis was almost the same as that reported in previous studies.
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    Journal of Morphology 143 (1974), S. 1-1 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Morphology 143 (1974), S. 337-347 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron microscopy revealed spores of Nosema apis and Thelohania fibrata to be egg-shaped, but only the mature spore of T. fibrata was shown to possess a horseshoe-like concavity at the posterior pole. Freezeetched preparations indicated that this concavity was due to a thin area of the spore coat. Freeze-etching studies also show spores of N. apis do possess an umbrella-shaped polaroplast, and a polar filament which is arranged in a double layer with over 30 coils. The spore of T. fibrata contains a pear-shaped arrangement of the polaroplast membrane, and a polar filament arranged in a single layer of 22 coils.
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  • 38
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    Journal of Morphology 142 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The fiber constituents and connections of the calyces  -  the input-receiving regions  -  of the corpora pedunculata (“mushroom bodies”) were studied in reduced silver preparations from the American cockroach, Periplaneta americana (L.). In the outer synaptic layer of the calyces five fiber classes were distinguished, the first three of which arise outside the mushroom body. (1) Four highly similar neurons with somata near the optic lobe branch into different parts of the ipsiateral protocerebrum, including both calyces. Their fibers are highly constant in arrangement and position and contain small nucleus-like bodies. (2) The tractus olfactorio-globularis (sensu lato) emits fiber groups which course along the calycal walls as “calycal tracts” before ultimately dissipating into the synaptic layer. Variability within these tracts is described. (3) Fibers of undertermined origin outside the mushroom body radiate from the calycal center outwards through the synaptic layer. (4) From the inner calycal layer of neurites belonging to intrinsic mushroom-body neurons, perpendicular collaterals enter the synaptic layer. (5) Intrinsic-neuron somata near the calycal rim emit fibers which course tangentially within the synaptic layer from calycal rim to center. These fibers form a special peripheral zone in the pedunculus.The predominant presumably afferent calycal fiber class is that derived from the tractus olfactorio-globularis. No evidence was found for tracts from optic lobe to calyces. On this basis, and in light of the experimental and comparative anatomical literature, it is suggested that the corpora pedunculata of P. americana and other pterygotes are fundamentally second-order antennal sensory processing centers.Conflicting observations in earlier reports are critically discussed.
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    Journal of Morphology 142 (1974), S. 301-319 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epidermis of Eisenia is covered by a cuticle and rests on a basement lamella. The cuticle, which is resistant to a variety of enzymes, is composed of non-striated, bundles of probable collagen fibers that are orthogonally oriented and are embedded in a proteoglycan matrix. The basement lamella consists of striated collagen fibers with a 560 Å major periodicity. Proximity and morphology suggest that the epidermis may contribute to both the cuticle and the basement lamella  -  that is, the single tissue may synthesize at least two types of collagen. The epidermis is a pseudostratified epithelium containing three major cell types (columnar, basal and gland) and a rare fourth type with apical cilia. The esophagus is lined by a simple cuticulated epithelium composed predominantly of a single cell type, which resembles the epidermal columnar cell. Rare gland cells occur in the esophageal epithelium, but basal cells are lacking.
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    Journal of Morphology 142 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Morphology 142 (1974), S. 351-363 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Gill development begins on the sixth day of incubation at 10°C and is complete by 31 days (hatching). Gill arches are formed by fusion and perforation of ectoderm and endoderm across the pharyngeal wall. A primary branchial artery forms within each arch and a second branchial artery forms as a branch from its ventral end. A series of filament loop vessels forms connecting the two arteries and when several are patent a unidirectional blood flow is established via afferent (second) branchial artery, filament loop vessels to efferent (primary) branchial artery. Part of the efferent branchial artery just above its junction with the afferent branchial artery constricts and occludes. It is suggested that this change in the pattern of blood flow is dependent on differences in resistance of the two branchial arteries. A later extension of the gill ventrally is thought not to be homologous with similar regions in elasmobranchs and Acipenser.
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Scanning and transmission electron microscopy studies were conducted on the antennal sensory sensilla of the hymenopteran parasitoid, Cardiochiles nigriceps Viereck, of the family Braconidae. Distinct morphological differences were found between the chemoreceptors of the male and female. Curved, non-fluted, thin-walled sensilla were found to be very abundant on the male and restricted in location and number on the female. Trichoid, placoid and fluted basiconic sensilla were numerous on the antennal flagella of both sexes. Smooth basiconic sensilla were restricted in number to one per flagellar segment in both sexes. Behavioral data suggest that bent-tipped, thick-walled sensilla unique to the female are involved in detecting a chemical(s) emitted from the host, Heliothis virescens (Fab.).
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    Journal of Morphology 144 (1974), S. 71-83 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The biomechanical role of the mammalian clavicle and the functional significance of the aclaviculate condition were investigated. Shoulder movements in rats (Rattus norvegicus) with excised clavicles were compared to those of normal rats by biplanar plate radiography. Shoulder movements during walking of the claviculate American opossum (Didelphis marsupialis), and aclaviculate raccoons (Procyon lotor) and cats (Felis domestica) were compared by biplanar cineradiography.The mammalian clavicle, where present in its complete form, exerts both a “spoke” and a “strut” effect on shoulder movement. By maintaining a fixed distance between the acromion and manubrium, the clavicle ensures that relative movement between these structures is arcuate. Aclaviculate mammals, in contrast, have linear shoulder excursions that are nearly parallel or slightly oblique to the median plane, depending on the conformation of the thorax. Medial collapse of the shoulder in aclaviculate rats demonstrates that the clavicle is under compression, and thus acts as a strut.Reduction or loss of the clavicle, which has occurred independently in numerous mammalian phylogenies, has been regarded as an adaptation for greater shoulder movement and hence increased stride. However, on present evidence clavicular reduction in cursorial mammals appears to be more directly related to a linear excursion of the shoulder joint and a restriction of limb movements to a sagittal plane.
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    Journal of Morphology 144 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The tail of Teratoscincus scincus has dorsal scales that have tubercles on their dorsal and ventral surfaces. Sounds are produced when these rub past each other as the excited animal moves its tail. The relative movement of scales is intensified by caudal torsion. The frequencies of the sounds cover a range from 9 to 25 kops and thus, differ from those produced during vocalizations.
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The locomotor function of the caudal muscle cells of ascidian larvae is identical with that of lower vertebrate somatic striated (skeletal) muscle fibers, but other features, including the presence of transverse myomuscular junctions, an active Golgi apparatus, a single nucleus, and partial innervation, are characteristic of vertebrate myocardial cells.Seven stages in the development of the compound ascidian Distaplia occidentalis were selected for an ultrastructural study of caudal myogenesis. A timetable of development and differentiation was obtained from cultures of isolated embryos in vitro.The myoblasts of the neurulating embryo are yolky, undifferentiated cells. They are arranged in two bands between the epidermis and the notochord in the caudal rudiment and are actively engaged in mitosis.Myoblasts of the caudate embryo continue to divide and rearrange themselves into longitudinal rows so that each cell simultaneously adjoins the epidermis and the notochord. The formation of secretory granules by the Golgi apparatus coincides with the onset of proteid-yolk degradation and the accumulation of glycogen in the ground cytoplasm.Randomly oriented networks of thick and thin myofilaments appear in the peripheral sarcoplasm of the muscle cells of the comma embryo. Bridges interconnect the thick and thin myofilaments (actomyosin bridges) and the thick myofilaments (H-bridges), but no banding patterns are evident. The sarcoplasmic reticulum (SR), derived from evaginations of the nuclear envelope, forms intimate associations (peripheral couplings) with the sarcolemma.Precursory Z-lines are interposed between the networks of myofilaments in the vesiculate embryo, and the nascent myofibrils become predominantly oriented parallel to the long axis of the muscle cell.Muscle cells of the papillate embryo contain a single row of cortical myofibrils. Myofibrils, already spanning the length of the cell, grow only in diameter by the apposition of myofilaments. The formation of transverse myomuscular junctions begins at this stage, but the differentiating junctions are frequently oriented obliquely rather than orthogonally to the primary axes of the myofibrils.With the appearance of H-bands and M-lines, a single perforated sheet of sarcoplasmic reticulum is found centered on the Z-line and embracing the I-band. The sheet of SR establishes peripheral couplings with the sarcolemma.In the prehatching tadpole, a second collar of SR, centered on the M-line and extending laterally to the boundaries with the A-bands, is formed. A single perforated sheet surrounds the myofibril but is discontinuous at the side of the myofibril most distant from the sarcolemma. To produce the intricate architecture of the fully differentiated collar in the swimming tadpole (J. Morph., 138: 349, 1972). the free ends of the sheet must elevate from the surface of the myofibril, recurve, and extend peripherally toward the sarcolemma to establish peripheral couplings.Morphological changes in the nucleus, nucleolus, mitochondria, and Golgi bodies are described, as well as changes in the ground cytoplasmic content of yolk, glycogen, and ribosomes.The volume of the differentiating cells, calculated from the mean cellular dimensions, and analyses of cellular shape are presented, along with schematic diagrams of cells in each stage of caudal myogenesis. In an attempt to quantify the differences observed ultrastructurally, calculations of the cytoplasmic volume occupied by the mqjor classes of organelles are included.Comparison is made with published accounts on differentiating vertebrate somatic striated and cardiac muscles.
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  • 49
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    Journal of Morphology 144 (1974), S. 85-117 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anolis embryos have limb buds at the time eggs are laid and require about 39 days to complete development at 28°C. Rathke's pouch is present at five days, and the subdivisions of the adenohypophysis are differentiated by ten days after oviposition. The cells of the rostral half of the pars distalis (PD) are derived from the anterior face of Rathke's pouch; cells of the caudal half from the posterior face. Lateral lobe cells differentiate on the lateral margins of the developing caudal PD, and knob-like outgrowths of this tissue attach to the walls of the diencephalon to form the pars tuberalis (PT). Subsequently, the cells of the PT lose their connection with the PD and become a pair of flattened oblong plaques. They reach maximal size in midincubation, and are gradually invaded by nervous elements and incorporated into the walls of the hypothalamus. Electron micrographs demonstrate that the embryonic PT is secretory.Ultrastructurally the pars intermedia (PI) and PD are composed of parenchymous secretory cells in a framework of stellate cells. Stellate cells surround the lumen of Rathke's pouch and are connected laterally by complex junctions that exclude the secretory cells from the luminal surface. They extend in sheet-like processes among the secretory cells to the outer margin of the gland where they form a partial sheath within the basal lamina around the secretory tissue. As development proceeds, the lumen becomes subdivided and the resulting reduced lumina are recognizable as the forerunners of the follicles of the adult adenohypophysis.The cells of the PI are differentiated into secretory or stellate cells halfway through incubation. At this time only half of the cells of the PD can be so classified. Four of the five granulated cell types described in the adult are recognizable by mid-incubation; the fifth cell type (prolactin cell) becomes distinguishable within ten days thereafter, and at hatching appears to be actively synthesizing secretory products.
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  • 50
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    Journal of Morphology 144 (1974), S. 131-141 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The hydranth of the gymnoblastic hydroid Syncoryne tenella is invested by a cuticle approximately 530 mμ thick which is continuous with the periderm of the hydrocaulus. The ectodermal cells of the hydranth possess regularly spaced microvilli orientated with their long axis perpendicular to the ectodermal surface. The microvilli project into the cuticle, and probably serve to anchor the cuticle to the ectoderm. In the hydrocaulus the periderm is loosely applied to the ectoderm: in this region microvilli are absent from ectodermal cells. The periderm is a layered structure composed of finely filamentous material. No structural basis is found for the previously reported differential staining of peridermal layers in the hydrocaulus.
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  • 51
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    Journal of Morphology 144 (1974), S. 167-183 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nuchal organs of polychaetes from four different families (Nereidae, Nephtyidae, Phyllodocidae and Glyceridae) were examined with the light and electron microscopes. In each case, the organ consists of ciliated cells and primary sensory elements. The ciliated cells are similar to the cells of the adjacent epidermis but bear motile cilia. Primary sensory neurons are situated within the organs in Nephtyidae and Phyllodocidae, but are located within the brain in Nereidae and Glyceridae. Each sensory cell gives rise to a distal process which penetrates between the ciliated cells to form an apical sensory bulb bearing modified cilia. Apically these processes are lined with juxtamembranous plaques. The ciliated cells are innervated by efferent axons from the brain, and in Nereis the axons appear to be peptidergic. The elements comprising the nuchal organs closely resemble those of the vertebrate olfactory mucosa.
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  • 52
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    Journal of Morphology 144 (1974), S. 143-165 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cuticle of five species of Oligochaeta, chosen to represent differences in size and a variety of biotopes, was studied electron microscopically after fixation with the acrolein-TAPO-osmium tetroxide method. Five distinct layers in the cuticle of all studied species were found. Staining with lead and uranyl ions or with silver proteinate visualized basically the same structural components of the cuticle, but the degree of electron opacity and the distribution of the electron-opaque stain in these components differed according to the staining method used. Since the acrolein-TAPO-osmium tetroxide method visualized the cuticular zones preferentially stained by Thiéry's silver proteinate method, it was concluded that the TAPO method may be considered suitable for the visualization of polysaccharides. Staining with phosphotungstic acid provided some information on the composition of the cuticle of Oligochaeta not obtained by staining ultrathin sections with lead and uranyl ions nor with silver proteinate. The conclusion is that phosphotungstic acid binds to polysaccharides which do not contain vicglycol groups nor active sites responsible for the positive reaction with lead and uranyl salts. Structural components in the cuticle of the oligochaetes studied were characteristic for each species. The taxonomic value of such components, however, must be confirmed by examination of a larger number of species of oligochaetes.
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  • 53
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Laboratory-reared outgrowths of the freshwater sponge Corvomeyenia carolinensis Harrison were examined using histological and histochemical techniques, supplemented by phase contrast observations of cellular behavior. The tissue and cellular components of the spongillid outgrowth region were defined in terms of function and morphogenic state. Archeocytes differ considderably, in both histochemical and morphological characteristics, from other cell types of the adult sponge, being histochemically similar to stem cells reported from a variety of developmental series. Archeocytes exhibit cytological characteristics of unspecialized cells capable of high levels of synthetic activity while other cell types of C. carolinensis, for the most part, can be characterized as fully differentiated cells displaying more restricted synthetic capabilities but often accumulating neutral mucoproteins. The presence of aggregates of amebocytes, not identifiable as archeocytes and possibly engaged in gemmule formation, is discussed in terms of current concepts of gemmulation and cellular developmental capabilities in sponges.
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  • 54
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    Journal of Morphology 143 (1974) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 55
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    Journal of Morphology 143 (1974), S. 435-443 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The long antennal flagellum of Neoconocephalus ensiger is covered with many sharp-tipped hairs that appear to be non-innervated; thick-walled chemoreceptors, that may also have a tactile function; thin-walled chemoreceptors of several kinds and coeloconic chemoreceptors. All of the chemoreceptors are innervated by small groups of neurons. The first flagellar subsegment is unusual in that it bears a small protuberance on its latero-ventral surface. This marks the site of the attachment, internally, of a scoloparium containing about eleven scolopales in which the dendrites of some 23 sensory neurons terminate. The most distal subsegment lacks the scoloparium reported earlier for the grasshopper. No conspicuous difference between the antennae of males and of females was found.
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  • 56
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    Journal of Morphology 143 (1974), S. 445-455 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The antennae of two species of thrips, Bagnalliella yuccae (Hinds) and Frankliniella tritici (Fitch), have been examined with the light and electron microscopes. The antennal flagellum of both species is provided with tactile hairs, thick-walled chemoreceptors and thin-walled chemoreceptors. In addition, B. yuccae, but not F. tritici, has a single coeloconic chemoreceptor on the dorsal surface of the pedicel. Observations were made on the fluids in the lumen of the antennae of E. yuccae in the living insect. The movement of the fluids probably has an important physiological significance.
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  • 57
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    Journal of Morphology 144 (1974) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 58
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The cervicothoracic muscles of nymphal and adult Euborellia annulipes (Lucas) are described, the former for the first time. In the adult, eight new muscles are identified, while the nymphs possess a further seven muscles that disappear at maturation or before. Otherwise the same muscles occur in nymphs as in adults, though some nymphal muscles are less clearly separated from one another than their adult homologs. The attachment sites of certain muscles show a number of slight differences between nymphs and adults. The work emphasizes the necessity of taking the immature musculature into account in assessing the muscular pattern represented in an insect order.
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  • 59
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Some of the cytological characteristics of the hemocytes of the scorpion, Palamnaeus swammerdami, were studied. The morphological features of the arachnid hemocytes were observed to be similar to those of hemocytes of insects, millipedes and isopods. Jones' system of hemocyte classification was extended to the arachnid hemocytes. The six classes of hemocytes indentified in the scorpion correspond to prohemocytes, plasmatocytes, granular hemoocytes, cystocytes, spherule cells and adipohemocytes of insects. A cell type comparable to oenocytoids of insects and crustaceans is absent. The prohemocytes can be subdivided into four categories that probably represent the precursors of the major cell types. The cytological characteristics of the major cell classes and the occurrence of the miniatures of some of these major cell types support the concept of Jones (62) that these cell types might have different cell lineages and might not be capable of transforming into one another. Some of the prohemocytes, plasmatocytes and granular hemocytes were amoeboid. The nature of the granules and the vacuoles of plasmatocytes and granular hemocytes were compared with the granules and vacuoles of corresponding hemocytes of other arthropods. Cystocytes did not bring about any visible coagulation similar to their counterparts in millipedes and crustaceans. Plasmatocytes, granular hemocytes and spherule cells were observed to occur in conglomerates. The cell types noted in the present study were compared with the hemocytes of other arachnids.
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  • 60
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    Journal of Morphology 144 (1974), S. 11-21 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphological features of the hemocytes of the crustacean Ligia exotica are similar to hemocytes of insects and millipedes. Jones system of hemocyte classification is extended to crustacean hemocytes. As in insects, seven classes of hemocytes, identified as prohemocytes, plasmatocytes, granular hemocytes, cystocytes, oenocytoids, spherule cells and adipohemocytes, occur. The prohemocytes can be subdivided into five categories that probably represent the precursor of major cell types. The structural and chemical features of other major cell classes are distinct and support the concept of Jones ('62) that these types might have different lineages and might not be capable of transforming into one another. Some of the prohemocytes, plasmatocytes and granular hemocytes are amoeboid. Cystocytes do not bring about any visible plasma coagulation similar to their counterpart in millipedes. Oneocytoids and adipohemocytes are rare. Plasmatocytes, cystocytes and oenocytoids occur in conglomerates, the significance of which is discussed. The cell types are compared with those of the hemocytes of other crustaceans. It is suggested that the nomenclature based on morphological characters is more suited for crustacean hemocytes than a nomenclature based on behavioural and physiological characters.
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  • 61
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Well preserved transitional cells were found between differentiated cells and horny cells of the frog epidermis, thus facilitating the study of the sequential events involved in horny cell formation. Autolysosomes appear to play an important role in the formation of horny cells. These structures preferentially digest those cytoplasmic components which are not necessary constituents of the terminal horny cell. The release of the contents of the small mucous granules into the intercellular spaces is one of the initial events in horny cell formation. Filaments and large mucous granules seem to be resistant to the lytic digestion and contribute to the bulk of the horny cell. Loss of fluids through the plasma membrane and consolidation of the remaining constituents, results in a flattened horny cell. The appearance of a thickened membrane around the horny cell signifies the completion of the transformation process.
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  • 62
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    Journal of Morphology 143 (1974), S. 285-305 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The three dorsal ocelli of worker honeybees have been studied by light and electron microscopy. Each ocellus has a single flattened spheroidal lens and about 800 elongated retinular cells. Retinular cells are paired and form a two-part plate-like rhabdom between their distal processes. Each rhabdomere comprises parallel microvilli projecting laterally from the apposed retinular cells. Primary receptor cell axons synapse within the ocellus with ocellar nerve fibers of two different calibers. Each ocellus has eight thick fibers ca 10 m̈m in diameter and several thinner ones less than 3 m̈m in diameter. Fine structural evidence suggests that retinular axons end presynaptically on both types of ocellar nerve fibers. Since all retinular cells apparently synapse repeatedly with the thick fibers this involves a convergence of about 100:1. Thick fibers always terminate postsynaptically within the ocellus while thin fibers terminate presynaptically on other thin fibers, thick fibers or retinular axons. Structural evidence for synaptic polarization indicates that retinular cells and thick fibers are afferent, thin fibers efferent. Thus complex processing of the ocellar visual input can occur before the secondary neurons of the three ocelli converge to form the single short ocellar nerve which runs to the posterior forebrain.
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  • 63
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    Journal of Morphology 143 (1974), S. 307-335 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functional morphology of the forelimbs of the following African Viverridae was studied, Atilax paludinosus, Bdeogale crassicauda, Civettictis civetta, Genetta genetta, G. tigrina, Helogale parvula, Herpestes ichneumon, H. sanguineus, Ichneumia albicauda, Mungos mungo, Nandinia binotata. Their locomotory behaviour has been previously studied and described and is related to morphological differences. The osteology of all the species and the myology of three species is described. The species have been assigned to primary locomotor categories on the basis of their locomotion. These are 1, climbing, arboreal walking; 2, arboreal and terrestrial walking and jumping; 3, general terrestrial walking and scrambling; and 4, trotting. In the climbing arboreal walking category the most distinctive morphological adaptations are powerful flexors and extensors as well as a flexible plantigrade manus with retractile claws. In the arboreal and terrestrial walking category the shoulder, elbow and carpal joints are flexible and the manus has retractile claws, though the flexor and extensor musculature is insufficiently developed for controlled climbing. The trotting category is characterised by a high humero-radial index and a rigid antibrachium. The foot is digitigrade with the claws short and stout. Species in the general walking and scrambling category show many differences in the morphology of their feet, even though the proximal parts of the forelimb appear similar. Due to the restricted nature of the adaptations, these species have been assigned to secondary locomotor categories. Morphological characters typical of the locomotor categories are summarized in the discussion.
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  • 64
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    Cell & tissue research 148 (1974), S. 11-26 
    ISSN: 1432-0878
    Keywords: Dentine ; Bone ; Collagen structure ; Collagen mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has been previously shown that the distances between the nuclei within the collagen bundles of mineralizing tissues were in good agreement with the repeat distances of the cross-banding pattern of collagen, which supports the assumption that the distances between the mineral deposits reflect to a good approximation the distances between nucleation centres on the collagen macromolecule. However, the lateral separation of the nuclei were significantly higher than the distances between close-packed triple helices. Recently a new model of collagen aggregation has been proposed in which the smallest morphological units are subfibrils (Ø approx. 39 Å) packed in tetragonal array. This led us to measure once again the lateral separation between a) close-packed calcium phosphate needles lying in bundles at (1) the mineralizing front of mantle dentine and (2) at the mineralizing front of rat tail bone, and b) between the uranyl-lead nuclei produced in the staining of rat tail tendon. The mean lateral distances separating these nuclei fell within the range of 39–47 Å, which is a little higher than the distances of 39 Å which separate the microholes between the subfibrils in the tetragonal packing model, which are regarded as the likely sites of nucleation. If, however, it is assumed that the forces generated during mineralization can cause the collagen fibres to swell, then the lateral separation of the nuclei and the distances between the microholes would correspond very closely.
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  • 65
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    Journal of Cellular Physiology 83 (1974), S. 27-34 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relationship between alkaline phosphatase activity and cell growth has been studied in hamster cells transformed by different carcinogens. About 90% of normal hamster embryo cells were constitutively positive for alkaline phosphatase activity (AP+). However, there were no AP+ cells in cell lines transformed after treatment with the chemical carcinogens dimethylnitrosamine or 4-nitro-quinoline-N-oxide and 0.02% and 4% AP+ cells in cell lines transformed by polyoma virus or Simian virus 40. The glucocorticoid hormone, prednisolone, induced alkaline phosphatase activity in 12% and 44% of the enzyme-negative (AP-) cells in cell lines transformed by polyoma or Simian virus 40, but this hormone did not induce alkaline phosphatase activity in AP- cells from cell lines transformed after treatment with the chemical carcinogens. Treatment of polyoma transformed AP- cells with the mutagen N-methyl-N′-nitro-N-nitro-soguanidine produced AP+ cells, whereas no AP+ cells were found after mutagen treatment of AP- cells from the chemically transformed cell lines. Studies on spontaneous segregation in the polyoma transformed cell line has shown that AP+ cells segregated AP- cells both in vitro and in vivo, although no spontaneous segregation was observed from AP- to AP+ cells.AP+ cells, compared to AP- cells, showed a decrease in DNA synthesis, cell multiplication, the ability to form colonies in soft agar and tumorogenicity in animals. AP- cells induced for alkaline phosphatase activity by prednisolone, showed the same growth properties in vitro as uninduced AP- cells. The decreased cell growth found in AP+ cells which were constitutive for alkaline phosphatase activity was therefore not found in the hormone induced AP- cells. The results indicate that constitutive alkaline phosphatase activity appears to be related to the regulation of cell growth and that AP- cells have a selective advantage over AP+ cells.
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  • 66
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pattern of changing activities of three lysosomal enzymes, N-acetyl-β-D-glucosaminidase, aryl sulfatase, and DNase II, and that of DNA polymerase was followed in homogenates of 3T3 cells during the logarithmic phase of growth and in stationary cultures. The change in activities of the polymerase and the lysosomal enzymes is antiparallel. DNA polymerase exhibits highest activity in growing cultures, and shows a three-fold decline of the specific activity in stationary cultures. The lysosomal enzymes show a very marked increase in their specific activity after density saturation is reached, which can be prevented by the addition of cycloheximide. Colcemid added to logarithmically growing cultures also causes an increase in the specific activities of lysosomal enzymes.
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    Journal of Cellular Physiology 83 (1974), S. 219-230 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A series of Chinese hamster cell lines were tested and found to be able to proliferate in the absence of added bicarbonate and carbondioxide if hypoxanthine and uridine were present in the medium. Conversely, cells incapable of salvaging one of these precursors, such as hypoxanthine-guanine phosphoribosyltransferase (HGPRT-) deficient cells did not multiply under these conditions.We describe another variant capable of utilizing hypoxanthine and uridine which has an absolute requirement for exogenous CO2/NaHCO3 for growth. These cells appear to be defective in the complete oxidation of pyruvate to carbondioxide, and indications are that the entry of pyruvate into the Krebs cycle is affected.
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    Journal of Cellular Physiology 83 (1974), S. 287-296 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Elevated calcium and magnesium concentrations promoted mitotic activity in rat thymic lymphocyte cultures. Oestradiol inhibited calcium- but not magnesium-induced mitogenesis. One prerequisite for the mitogenic action of calcium is a raised intracellular concentration of cyclic adenosine 3′5′ monophosphate (cyclic AMP) but cyclic AMP-induced mitogenesis was insensitive to oestradiol. This suggests that the steroid blocks the mitogenic process at a stage preceding the endogenous cyclic AMP elevation. Furthermore the mitogenic actions of adrenaline, which stimulates adenylate cyclase (the enzyme responsible for cyclic AMP biosynthesis), and caffeine, which inhibits phosphodiesterase (the enzyme which degrades cyclic AMP) were also insensitive to oestradiol inhibition. This precludes a direct effect of the steroid on these enzymes. However, oestradiol did inhibit the mitogenic action of parathyroid hormone (PTH). Since the mitogenic action of PTH probably involves increased calcium entry to the cell, oestradiol may block this ion influx.The inhibition of calcium- and PTH-induced mitogenesis must be attributable to some structurally specific action of oestradiol. The steroids cholesterol, progesterone and testosterone all failed to reduce calcium-induced mitogenesis, whereas both α and β oestradiol were effective.In addition to its insensitivity to oestradiol inhibition, magnesium-stimulated mitosis was unaffected by both imidazole and calcitonin at concentrations which significantly reduced calcium-stimulated proliferation. These findings are compatible with the thesis that magnesium-induced mitogenesis does not involve the elevation of cyclic AMP concentrations.
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    Journal of Cellular Physiology 83 (1974), S. 337-343 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The transport of various deoxyribonucleosides by cultured Novikoff rat hepatoma cells (subline N1S1-67) follows normal Michaelis-Menten kinetics. The transport reactions are competitively inhibited by most heterologous deoxy- and ribonucleosides and by Persantin and Cytochalasin B. Comparisons of the transport kinetics of the various deoxyribonucleosides (Km and Vmax ) and of the Km/Ki ratios for the inhibitions indicate that deoxythymidine, deoxyuridine and 5-fluordeoxyuridine are transported by a single system, whereas deoxycytidine and the purine deoxyribonucleosides are transported by other systems. The data suggest that deoxyadenosine, deoxyguanosine and deoxyinosine, are not transported by a single system, but the number of transport systems involved could not be established unequivocally. Similar comparisons also suggest that the deoxyribonucleosides are transported by different systems than the ribonucleosides. All deoxyribonucleoside transport systems are inhibited to about the same extent by Persantin (Ki = 1-2 μM) and Cytochalasin B (Ki = 4-12 μM). The inhibitions of deoxynucleoside transport resulted in corresponding apparent competitive inhibitions of their incorporation into nucleic acids.
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    Journal of Cellular Physiology 83 (1974), S. 321-336 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The incorporation of 3H-labeled deoxyadenosine and deoxyguanosine into nucleic acids by cultured Novikoff rat hepatoma cells is about 80% into RNA and 20% into DNA. The pathways of incorporation have been elucidated in studies with whole cells and cell-free extracts. Deoxyadenosine is very rapidly deaminated to deoxyinosine. Most of the deoxyinosine formed by whole cells is transported out of the cells and accumulates in the medium. A portion of the deoxyinosine, and deoxyguanosine are phosphorolyzed by purine nucleoside phosphorylase to hypoxanthine and guanine, respectively. The latter are subsequently converted by hypoxanthine-guanine phosphoribosyl transferase to IMP and GMP, respectively. Incorporation of the purine deoxyribonucleosides into DNA is mainly via this pathway and the subsequent reduction of ADP and GDP by ribonucleoside reductase, although a small proportion of the deoxyadenosine and deoxyguanosine taken up by the cells seems to be directly phosphorylated to dAMP and dGMP, respectively. Deoxyguanosine is incorporated only into guanine residues of RNA and DNA. Deoxyadenosine is also mainly incorporated into guanine residues of RNA and DNA, although the radioactivity of deoxyadenosine in the acid-soluble pool is almost exclusively associated with ATP. A similar labeling pattern is observed with labeled deoxyinosine, inosine or hypoxanthine. The pyrimidine deoxyribonucleosides, on the other hand, are specific precursors for their respective bases in DNA.Hydroxyurea inhibits the incorporation of all deoxyribonucleosides into DNA. Results from pulse-chase experiments indicate that the inhibition of DNA synthesis is prevented by the presence of high concentrations of deoxyadenosine plus deoxyguanosine in the medium. Either purine deoxyribonucleoside alone or deoxycytidine, hypoxanthine or inosine alone or in combination with deoxyadenosine or deoxyguanosine are ineffective. The results are consistent with the conclusion that the inhibition of DNA synthesis is due to a depletion of the dATP and dGTP pools as a result of the hydroxyurea treatment. On the other hand, hydroxyurea causes an increased incorporation of thymidine and deoxycytidine into the dTTP and dCTP pools, respectively. Evidence is presented to indicate that this effect of hydroxyurea is due to an increased synthesis of dTTP and dCTP rather than to an inhibition of their turnover.
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    Journal of Cellular Physiology 83 (1974), S. 353-357 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: HTC cells incubated in the absence of serum for more than 14 hours have very low levels of ornithine decarboxylase, the first enzyme on the pathway of polyamine synthesis. Readdition of serum causes an increase in the activity of ODC, reaching a maximum on average 17 times above the basal level after five hours. This increase is due in part to a decrease in the apparent rate of degradation of ODC, and also to a stimulation of its synthesis. Within the first two hours the serum induction of ODC is resistant to Actinomycin D. Insulin at 5 μm/ml alsocauses an increase in ODC activity but only after a delay of two hours, in contrast to its more rapid stimulation of tyrosine transaminase activity.
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  • 72
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    Journal of Cellular Physiology 83 (1974), S. 243-250 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Net fluxes of sodium and potassium were studied in Ehrlich mouse ascites tumor cells during contact with the agglutinating protein, concanavalin A. This lectin altered cation transport markedly at concentrations of 20-105 μg/ml (6-47 μg/mg cell protein). Whereas control cells extruded sodium and maintained or accumulated potassium against electrochemical gradients, in the presence of concanavalin A there was rapid net sodium entry and potassium loss. After 10-20 minutes in concanavalin A, sodium extrusion began and potassium loss diminished but these events were prevented by ouabain. The alterations in cation content induced by concanavalin A are unlikely to be the result only of agglutination since soybean agglutinin caused much smaller changes although it agglutinated the cells equally well.
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  • 73
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    Journal of Cellular Physiology 83 (1974), S. 203-210 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of cell density on morphological transformation of chick embryo cells by Rous Sarcoma Virus (RSV) was examined in this study, and a cell density optimum for transformation was found. Less than 10% of the transformed foci appearing at the optimum density (2.5 × 104 cells per cm2) developed at high cell densities, and the diameters of the foci (an indication of the number of cells per focus) decreased with increasing cell density. No correlation was found between the decrease in transformation at high cell densities and the effect of cell density on the initial rate of cell proliferation, although dissociation of transformation from incorporation of radioactive precursors into nucleic acids could not be established. Redistribution of cells infected at high density showed that only a small proportion of successfully infected cells developed into foci. The results indicate that transformation of cells containing the RSV genome can be suppressed by physiological factors accompanying high cell density.
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  • 74
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    Journal of Cellular Physiology 84 (1974), S. 115-125 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ehrlich cells subjected to anisoosmolar media show very rapid volume changes. In hypertonic media they shrink. In hypotonic media they swell but the rapid initial swelling is followed by a regulatory shrinkage lasting ca. 30 minutes.Cells suspended in media with identical ionic concentrations but different total osmolarity (adjusted by sucrose) were compared. These studies revealed that swollen cells adjust their volume by decreasing the amount of intracellular K+ and ninhydrin positive substances. Intracellular Na+ and ATP concentrations were unchanged. Accordingly 42K+ flux analysis showed that the (passive) cell membrane permeability for K+ is increased to a minor degree and the Na+ permeability unaffected. The increased K+ permeability could not be correlated to an increase in 45Ca2+ influx.
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  • 75
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    Journal of Cellular Physiology 84 (1974), S. 141-145 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The membrane potentials of human embryonic lung fibroblasts have been measured in different cellular environments. Sparse cells on plastic have a mean membrane potential of -8.5 mV. As the cells progress to dense culture, the mean membrane potential rises to -14.7 mV. The mean membrane potential of fibroblasts in human embryonic lung fragments by comparison was found to be -16.5 mV. Sparse cells on collagen, at the same density as the sparse cells on plastic, have mean membrane potentials of -10.8 mV.Sparse cells on plastic migrating from dense cellular areas, following a cut being made in a thick sheet of cells, have mean membrane potentials of -5.9 mV.The significance of these results in relation to cellular environments has been discussed.
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  • 76
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    Notes: Using a combination of DNA-cytophotometry and tritiated thymidine-autoradiography, we have shown that the majority of nondividing cells in serially propagated human diploid cell populations have the 2C DNA content consistent with their being arrested in the G1 phase of the diploid cell cycle. Unlabeled 4C cells appear increasingly with time in culture. These may be arrested G2 diploids or they may be G1 tetraploids, since there is an associated increase in polyploidy in older cultures as evidenced by the appearance of labeled 8C cells.
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  • 77
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    Journal of Cellular Physiology 84 (1974), S. 253-259 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Secondary cultures of human diploid fibroblasts were used to study the effect of pH on cellular proliferation. In nonconfluent cultures, the growth rate at pH 7.1 was similar to that at pH 7.7 regardless of serum concentration. However, the saturation density achieved at pH 7.7 at any serum concentration was always 2-4 times that achieved at pH 7.1, although the greatest differences in saturation density were observed at the higher serum levels. The results suggest that the effect of pH on saturation density is due to two factors. One, cells at pH 7.1 seem to have a greater ability to undergo contact-inhibition than at pH 7.7, independent of any serum functions; and, two, confluent cells in medium at pH 7.1 are somewhat less sensitive to growth stimulation by increasing serum concentration than are confluent cells raised in medium at pH 7.7.
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  • 78
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    Journal of Cellular Physiology 84 (1974), S. 291-299 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In phototrophic culture of Euglena gracilis, good synchrony was found only under rather restricted programs of light-dark cycles, and rather narrow ranges of temperature and light intensity, when cultures were flushed with air fortified with adequate amounts of CO2. When flushed with air alone, CO2 was found to be limiting, and while cell divisions were rhythmic, less than a doubling of cell number occurred in division bursts. With air as gas phase, rhythmic division activity was maintained over wide ranges of temperature, light intensity, and the ratio of light:dark in a given program; all these factors affected the amplitude of the division burst, however.
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  • 79
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    Journal of Cellular Physiology 84 (1974), S. 319-332 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryoid bodies are produced when a transplantable testicular teratoma from strain 129 mice is serially passaged in the peritoneal cavity of these mice. These bodies are roughly spherical containing two morphologically distinct cell types. Scanning and transmission electron microscopy have been employed to show that the endodermal cells of embryoid bodies, like those of the mouse embryo, are on the outer surface and have highly convoluted surfaces containing numerous microvilli-like projections. The inner, embryonal carcinoma cells, are the pluripotent stem cells of this tumor.Intracisternal A-type particles have been observed in electron micrographs and are almost exclusively located in the endodermal cells of the embryoid bodies. The A-type complement-fixing antigen has been identified in extracts prepared from this tumor.When embryoid bodies are placed in culture and allowed to attach to the surface of a petri dish, a large number of new morphologically distinct cell types appear. Attachment to the petri dish surface is required for the generation of these new cell types. Cells of similar morphology in culture, display a distinctly “clonal” distribution on the petri dish surface.
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  • 80
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    Journal of Cellular Physiology 84 (1974), S. 481-485 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Following enucleation of a portion of human culture cells containing 3H-pyridine nucleotides, autoradiography revealed no difference in the grain density over enucleated and whole cells. These results provide evidence that the concentration of pydine nucleotides does not differ by more than threefold between nucleus and cytoplasm and probably does not vary at all.
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  • 81
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    Journal of Cellular Physiology 83 (1974), S. 11-18 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A single hematocytoblast in the yolk sac of the chick embryo has been shown previously to give rise on the average to a clone of 128 erythrocytes. Furthermore, in any given generation the erythroid cell synthesizes a characteristic amount of hemoglobin (Hb). In these experiments day 4 embryos were treated with FUdR for 12 hours, and then reversed with thymidine. We have monitored both the passage of these erythroblasts through the cell cycle, and the effect of this perturbation on the Hb content of single cells. As a result of this disruption the amount of Hb synthesized in a given generation can be varied, but the final amount of Hb/cell in the mature erythrocyte is the same as in the untreated controls. Apparently the total amount of the Hb/cell does not in itself influence the passage of the cell through the cycle. The coefficients of variation of the Hb values in the mature erythrocytes from both normal an perturbed embryos are similar.
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  • 82
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    Journal of Cellular Physiology 83 (1974), S. 43-51 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper reports the isolation of a phenotypically stable line of Chinese hamster ovary cells which exhibits a temperature dependent alteration in the transport of some purines. The alteration manifests itself for the uptake of guanine, hypoxanthine, azaguanine and guanosine but not for adenine, adenosine or thymidine. Studies with crude cell extracts suggest that, at the temperature the alteration is being expressed, the HGPRT activity is within the normal range. In cell-cell hybridization studies the alteration behaves as a recessive genetic trait.
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  • 83
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    Journal of Cellular Physiology 83 (1974), S. 69-74 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mammalian cell populations may be enriched for temperature-sensitive (ts) mutants by the tritiated thymidine (3H-TdR) suicide procedure (Thompson et al., '71). Such procedures were carried out on the near-diploid Chinese hamster ovary (CHO) cell line and on a line made “tetraploid” by Colcemid treatment. Clones of ts mutants were obtained from the diploid line, but in spite of repeated attempts, no ts mutants were isolated from the tetroploid line. The phenotypes of the new diploid ts mutants recovered were consistent with the particular selection regime employed.
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  • 84
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    Notes: In cultured fibroblasts, a mutation resulting in deficiency of a pyrimidine salvage enzyme leads to excretion of related pyrimidines. For example, absence of thymidine kinase led to loss of thymidine and deoxyuridine, and absence of deoxycytidine kinase to loss of deoxyuridine. Both wild type and mutant cells excreted uracil; if established lines are representative in this respect, a fully adequate salvage system for uracil does not seem to be present in the fibroblast.
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  • 85
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    Journal of Cellular Physiology 83 (1974) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 86
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    Journal of Cellular Physiology 83 (1974), S. 345-351 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ornithine decarboxylase activity in high density, stationary phase rat hepatoma (HTC) cells in suspension culture has an extremely short half-life of between 5 and 15 minutes, as measured after inhibiting protein synthesis. Following dilution of these cells into fresh medium there is a large increase in ornithine decarboxylase activity, reaching a peak often several hundred times the initial level at about four hours. At least part of this stimulation is due to an increase in the apparent half-life of the enzyme, to between 30 and 90 minutes. Evidence is presented that the supply of amino acids can control the turnover of ODC under some conditions. For example supplementing high density cells with glutamine, asparagine, serine, glycine and proline, either singly or together, increases ODC activity and decreases its apparent turnover. The stimulation by amino acids is enhanced by serum.
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  • 87
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    Journal of Cellular Physiology 83 (1974), S. 369-378 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mouse peritoneal exudate cells induced by thioglycollate medium can form colonies in soft agar with a plating efficiency of about 5% (0.6%-10%). Cells from an unstimulated peritoneal cavity form no colonies or have a plating efficiency of less than 0.001 %. These colony-forming cells from the peritoneal exudate are similar to bone marrow colony-forming cells in vitro in that they both require a substance(s) present in conditioned medium from L-cells or mouse embryo fibroblasts or the serum from endotoxin-treated mice for the initiation and the continuation of their growth. However, peritoneal exudate colony-forming cells have a much longer initial lag period (10-14 days) and can survive longer in the absence of L-cell conditioned medium than bone marrow colony-forming cells. Only mononuclear cells, presumably macrophages, are observed in peritoneal exudate colonies, whereas bone marrow cell colonies contain both polymorphonuclear cells and macrophages.
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  • 88
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    Notes: Calcium is required for ACTH stimulated steroidogenesis in adrenal tumor cells in tissue culture. In the absence of calcium, the dose of ACTH required to induce half maximum steroidogenesis was increased 30 fold. In contrast to intact adrenal glands or isolated adrenal cells, high doses of ACTH (50 mU/ml) maximally stimulated steroidogenesis in the absence of calcium. Growth for up to six days in medium with low calcium did not affect basal or ACTH induced steroidogenesis. The addition of calcium to cells incubated with ACTH produced a maximum steroidogenic response in 15 minutes. In contrast to intact adrenal glands, calcium is not required for adenosine-3′,5′-cyclic monophosphate (cyclic AMP) stimulated steroidogenesis in adrenal tumor cells. These experiments support the concept that calcium is important at the level of ACTH-membrane receptor site interaction or activation of adenyl cyclase in adrenal tumor cells.
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  • 89
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Redistribution of surface immunoglobulins (Ig), H-2b, Thy-1.2 and TL. 1,2,3 alloantigens, and concanavalin A (Con A) receptors on mouse thymus, lymph node and spleen cells into “caps” induced by bivalent antibodies or ligands was compared by immunofluorescence. Surface Ig was capped rapidly following attachment of anti-Ig antibody at 37°. Capping of alloantigens and Con A receptors occurred very slowly following attachment of alloantibody or Con A, but much more rapidly after addition of a secondary bivalent antibody. An inverse relationship between the number of surface component sites per cell and the extent of capping of that component was observed. Capping of alloantigens sparsely represented on the cell surface was not inhibited by high concentrations of alloantibody, in contrast to capping of alloantigens present in greater quantities. These results suggest that factors in addition to molecular cross-linking may be involved in ligand-induced redistribution of cell surface components.
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  • 90
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    Journal of Cellular Physiology 84 (1974), S. 29-36 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The potassium content of single human red cells was measured with an electron probe. Cells were placed on beryllium discs and coated with a thin layer of dibutyl pthalate to prevent loss of cellular contents. Samples were stable under the electron beam during analysis for more than 15 minutes and could be stored for long periods of time. Primary standards were prepared by loading red cells with varying known amounts of potassium in order to circumvent the corrections for absorption. The X-ray intensity was found to be directly proportional to the potassium content of the cells.
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  • 91
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    Journal of Cellular Physiology 84 (1974), S. 69-73 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cAMP levels of the 3T3 cell line and its transformed derivatives were determined. The level was found to be lower in transformed cell lines than in parental 3T3 and to decrease at confluence in all cell lines tested. SV40 transformed 3T3 cell lines which are temperature sensitive in growth control were found to have lower cAMP levels than 3T3, but these levels were not temperature dependent. Retransformation of these cell lines by murine sarcoma virus did not markedly affect their cAMP levels.
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  • 92
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    Journal of Cellular Physiology 84 (1974), S. 57-68 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Regulation of the proliferation of transplanted colony forming units (CFUs) was investigated in lethally irradiated mice, pretreated by methods known to accelerate hemopoietic recovery after sublethal irradiation. Prospective recipients were exposed to either hypoxia, vinblastine or priming irradiation and at different intervals thereafter lethally irradiated and transplanted with bone marrow. Repopulation of CFUs was determined by counting the number of splenic colonies in primary recipients or by retransplantation.Regeneration of grafted CFUs was greatly accelerated and their self-renewal capacity increased in mice grafted within two days after hypoxia. Also the number of splenic colonies formed by grafted syngeneic CFUs as well as by C57BL parent CFUs growing in BC3F1 hosts was significantly increased. The effect was not dependent on the seeding efficiency of CFUs and apparently resulted from hypoxia induced changes in the hosts physiological environment. Proliferative capacity of grafted CFUs increased remarkably in hosts receiving vinblastine two or four days prior to irradiation. Priming irradiation given six days before main irradiation accelerated, given two days before impaired regeneration of CFUs. The increased rate of regeneration was not related to the cellularity of hemopoietic organs at the time of transplantation. The growth of CFUs in diffusion chambers implanted into posthypoxic mice was only slightly improved which does indicate that the accelerated regeneration of CFUs in posthypoxic mice is mainly due to the changes in the hemopoietic microenvironment. A short conditioning of transplanted CFUs by host factor(s) was sufficient to improve regeneration. The results might suggest that the speed of hemopoietic regeneration depends on the number of CFUs being induced to proliferate shordy after irradiation, rather than on the absolute numbers of CFUs available to the organism.
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  • 93
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    Notes: During the early developmental stages of the toad, Bufo arenarum, Hensel. up to the stage of gill circulation (150 hr of development at 20-25°C) the total phospholipids content as well as that of phosphoglycerides of choline and of ethanolamine were found unchanged. The subfraction of both phosphoglycerides were separated according to the number of double bonds on silver-ion chromatography and were also found to be unchanged up to the tail bud stage. The distribution of non-polar side chains in the subfractions varied in both phosphoglycerides showing a structural heterogeneity. In the phosphatidylethanolamines predominate the polyenoic containing subfractions.In contrast with the constant concentration of polar lipids, during early embryogenesis a steady increase in 32P incorporation into phospholipids takes place when oocytes labeled during oogenesis are used. These changes were also correlated with the DNA content up to gill circulation stage.It is proposed that most of the nascent membrane polar lipids during early embryogenesis may be derived from a storage site through an active and specific intracellular redistribution process. At the arrival of the polar lipid to the nascent membrane a change in their covalent structure by introduction of a phosphorylbase from a highly labeled pool may explain the raise in specific activity. This change may be necessary to make possible the assembly of the lipid into the membrane structure.
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  • 94
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    Journal of Cellular Physiology 84 (1974) 
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  • 95
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    Topics: Biology , Medicine
    Notes: A recently described pituitary chondrocyte growth factor (CGF) is a contaminant of several related glycoprotein hormones (TSH, LH and HCG). Chondrocytes were cultured from rabbits two to three months old. Bovine TSH (NIH) 69.5 μg/ml, used as the source of CGF, reduced the generation time from 16 to 10 hours through a virtual effacement of the G1 period. Incorporation of 3H-thymidine declined rapidly after 48 hours from maximal values (control 300 cpm/μg DNA; CGF, 679). Total DNA accumulated thereafter until 116 hours when the figures were 36 and 98 μg/flask, respectively. Little growth response occurred in spinner cultures. CGF lowered plating efficiency from 4.5 to 2.3%. The stimulatory effect diminished when CGF was removed from the medium. The treated cells were smaller and contained less protein and RNA than controls. They synthesized smaller quantitites of sulfated mucopolysaccharides (chondroitin sulfates 4,6 and doubly sulfated chondroitin as well as some dermatan sulfate) but hyaluronate production was not diminished.
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  • 96
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    Topics: Biology , Medicine
    Notes: A flow-system multiparameter cell analyzer that simultaneously measures and processes fluorescence and cell volume signals from single cells was used to study the binding of fluorescein-conjugated Concanavalin A (Con A-F) to the cell surface. Cells reacted with Con A-F were passed through a flow chamber where sensors measured both cell volume and fluorescence of each individual cell. Sensor signals were electronically processed by first converting the cell volume signals to two-thirds power (proportional to surface area) and then forming the fluorescence-to-surface area ratio. These ratios, which were considered as estimates of the surface density of binding sites, were displayed as frequency distribution histograms using a multichannel pulse-height analyzer for various cell populations differing in cell size. Comparisons between cell lines showed characteristic differences in binding site density. Cell cycle dependent changes were not found for CHO cells synchronized by mitotic selection. An important benefit of this analysis method was the ability to quantitate very weak cell surface fluorescence.
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  • 97
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    Notes: The factors involved during the pumping of a particle suspended in an electrolyte through a small cylindrical orifice across which exists an electric field are reviewed, and their practical application to cell volume measurement in terms of orifice geometry and particle properties is considered. Procedures are described to determine whether a particular cell type satisfies the operational criteria of a rigid, non-conducting sphere, for which the theoretical expressions can be reduced to an especially simple form under appropriate conditions.Experimental results are presented for the case of chick, mouse and human lymphocytes, all of which are shown to satisfy the above requirements. Volume distributions are provided for chick blood lymphocytes and compared with those from various lymphatic organs; representative data are also reported for different types of mouse lymphocytes. Human blood lymphocytes are found to have normally-distributed diameters (p 〉 98%), a property not shared by their volumes or their surface areas, nor by blood lymphocytes from the chick or from patients with chronic lymphatic leukemia. A possible implication of this finding is mentioned briefly.
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  • 98
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    Journal of Cellular Physiology 84 (1974), S. 237-252 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Metabolic cooperation is a form of cell communication in which the mutant phenotype of enzyme deficient cells, as determined by incorporation of labeled substrates, is corrected in culture by contact with normal cells. Previous studies showed that metabolic cooperation between normal and hypoxanthine phosphoribosyl transferase deficient cells (HPRT-) was the result of transfer of product of the enzyme, nucleotide or nucleotide derivative, from normal to mutant cells rather than transfer of enzyme or informational macromolecules leading to the synthesis of the enzyme.In the present study the nature and mechanisms involved in these cell interactions were investigated. Effective communication is observed within one hour of cell contact. Modifications of the extracellular environment including changes in osmolarity, concentration of sodium and divalent ions failed to interfere significantly with transfer. Changes of cell shape induced by cyclic nucleotides, hormones and urea also did not affect communication. Cytochalasin B which dissociates microfilaments and binds to cell membranes reduced metabolic cooperation while colcemide which dissociates microtubules had little effect. Enzymatic oxidation and iodination of cell surface structures abolished metabolic cooperation. The subcellular localization of label in donor cells is important in determining efficiency of transfer. Metabolic cooperation is efficient when radioactive label is primarily located in the nucleus and inefficient if the label is cytoplasmic. Cell lines previously classified as “non-communicating” because they lack gap junctions, ionic coupling and metabolic cooperation were shown in the present study to communicate when incubated with labeled substrates for 20 hours rather than 3. Cell communication is a more generalized phenomenon among cells in contact than previously appreciated.
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  • 99
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When embryoid bodies are grown in suspension culture in vitro, they undergo only a limited amount of morphological development. When these same embryoid bodies are permitted to attach to the surface of a culture dish, a wide variety of new morphological cell types appear.Suspension cultures of embryoid bodies do not contain significant detectable levels of acetylcholine esterase or creatine phosphokinase. These same enzymes however are produced in cell cultures derived from embryoid bodies attached to the culture dish surface. Polyacrylamide gel electrophoresis has been employed to demonstrate that the electrophoretic form of creatine phosphokinase produced by teratoma cells in culture is the brain form of the enzyme.Solid transplantable tumors containing only embryonal carcinoma cells (stem cells) do not contain either of these enzymatic activities. Well differentiated transplantable teratomas contain both enzymes.
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 84 (1974), S. 343-348 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Agglutinability with Concanavalin was studied as function of cell cycle transition in normal and SV40 virus transformed 3T3 cells. In synchronized cultures of normal cells, agglutinbility was high during mitosis and disappeared rapidly. Agglutinability of transformed cells remained high in G1 phase but diminished gradually upon entering S phase and reached minimum in G1 phase. Decreased agglutinability a the end of the cell cycle was also observed in synchronous SV3T3 cultures by a combined technique of haemadsorption and density gradient centrifugation. In normal 3T3 cells, similar variations in agglutin ability during interphase could not be observed.
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