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  • Calcium  (32)
  • Ovary
  • Springer  (42)
  • Nature Publishing Group
  • 1970-1974  (42)
  • 1974  (21)
  • 1970  (21)
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  • Springer  (42)
  • Nature Publishing Group
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  • 1970-1974  (42)
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  • 1
    Electronic Resource
    Electronic Resource
    Additional evidence for the binding of calcium ions to elastin at neutral sites (1974)
    Springer
    Calcified tissue international 14 (1974), S. 317-325 
    Details
    ISSN: 1432-0827
    Keywords: Calcification ; Neutral sites ; Elastin ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des études précédentes suggèrent la présence de groupements carboxyles, sulfhydriles et aminés dans les sites de liaison en calcium de l'élastine. La possibilité de l'existence de sites neutres de liaison en calcium au niveau de l'élastine a été étudiée dans ce travail. Une augmentation de la fixation du calcium au niveau de l'élastine est observée après des modifications de dissolution qui ont aussi provoqué des modifications de structure de la protéine. Dans des mélanges méthanol-H2O, les liaisons du calcium semblent indépendantes du pH et de la force ionique. Sur dix ions testés (Ca2+, CO2+, Na2+, Cu2+, Zn2+, Cr3+, Pb+2, K+, Rb+ et Mg2+) seule la liaison du calcium est nettement augmentée, lorsque le méthanol est ajouté. Il semble que les sites neutres sont importants pour les divers rapports entre calcium et élastine et servent, peut-être, comme centres de nucléation au cours de la calcification de la protéine.
    Abstract: Zusammenfassung Vorgängige Studien haben die Bedeutung der Carboxyl-, Sulfhydryl- und Aminogruppen als Stellen der Calciumbindung im Elastin gezeigt. Die vorliegende Arbeit hatte zum Ziel, die Rolle der neutralen Koordinationsstellen im Elastin als mögliche Calcium-Bindungsseite abzuklären. Die Calciumbindindung an das Elastin wurde durch solche Lösungsmittelveränderungen erhöht, die auch gleichartige Verschiebungen im Proteinmolekül bewirkten. In Methanol-Wasser-Mischungen schien die Calciumbindung nicht von Veränderungen des pH oder der Ionenstärke abhängig zu sein. Von 10 Ionen, bei welchen die Bindung überprüft wurde, war einzig diejenige des Calciums signifikant erhöht, wenn Methanol zugesetzt wurde. Es wird vorgeschlagen, daß die neutralen Stellen für die verschiedenen Vorgänge, bei welchen Calcium und Elastin beteiligt sind, eine wichtige Rolle spielen und vielleicht für die Verkalkung der Proteine als Nukleationszentren in Frage kommen.
    Notes: Abstract Previous studies have implicated carboxyl groups, sulphhydryl groups and amino groups as the sites for calcium binding in elastin. In this study, the concept was investigated that neutral co-ordinating sites in elastin may also provide calcium binding sites. Calcium binding to elastin was increased upon solvent changes which also effected conformational changes in the protein. In methanol-H2O mixtures calcium binding appeared to be independent of changes in pH and ionic strength. Of ten ions tested (Ca2+, Co2+, Na+, Cu2+, Zn2+, Cr3+, Pb+2, K+, Rb+, and Mg2+), only calcium binding was significantly increased when methanol was added. It is proposed that neutral sites are important to the various relationships involving calcium and elastin and perhaps serve as nucleation centers in the calcification of the protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02060306
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of vitamin D analogues on bone resorption (1974)
    Springer
    Calcified tissue international 15 (1974), S. 333-339 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02059069
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of age on bone calcium and phosphate metabolism in organ culture (1974)
    Springer
    Calcified tissue international 16 (1974), S. 89-92 
    Details
    ISSN: 1432-0827
    Keywords: Age ; Bone culture ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Calvaria taken from mice aged 0, 1, 3 and 5 days were cultured for 48 h, in control medium (no added hormone), or in the presence of PTH (0.5 U/ml) or CT (50 mCl/ml). In the control group, there was a shift from net uptake of Ca and P (0- and 1-day bones) to net release (5-day bones). CT-treated bones of all ages took up Ca from the culture medium, but the percentage uptake declined with increasing age. Bones exposed to PTH released Ca and P to the culture medium, regardless of age. The changes with increasing age may be related to an increase in mineralization and other aspects of maturation in these bones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008215
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  • 4
    Electronic Resource
    Electronic Resource
    Serum calcium, phosphate and alkaline phosphatase and morphometric bone examinations in 30 patients with renal insufficiency (1974)
    Springer
    Calcified tissue international 16 (1974), S. 129-138 
    Details
    ISSN: 1432-0827
    Keywords: Serum ; Calcium ; Phosphate ; Alkaline phosphatase ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In 30 patients with chronic renal insufficiency (16 non-dialysed and 14 on dialysis) serum calcium, phosphate and alkaline phosphatase were determined and, in a crest biopsy specimen, morphometric determinations of bone qualities were calculated. A positive correlation was established between serum alkaline phosphatase, the osteoblast surface and the active resorption surface in both dialysed and non-dialysed patients. A positive correlation was also established between the osteoblast surface and the active resorption. In the non-dialysed patients a negative correlation was established between serum calcium and the osteoid surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008218
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  • 5
    Electronic Resource
    Electronic Resource
    Effects ofSolanum malacoxylon on embryonic bonein vitro and on isolated mitochondria (1974)
    Springer
    Calcified tissue international 16 (1974), S. 219-226 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008229
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of ethylenediaminetetraacetate (EDTA) on urinary excretion of hydroxyproline, calcium and phosphorus in the rat (1974)
    Springer
    Calcified tissue international 16 (1974), S. 1-12 
    Details
    ISSN: 1432-0827
    Keywords: EDTA ; Bone resorption ; Parathyroid hormone ; Calcium ; Hydroxyproline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The effects of ethylenediaminetetraacetate (EDTA) were studied in rats. Intravenous infusion of 4.84 mM Na2EDTA increased the urinary excretion of calcium six-fold, phosphorus three-fold and hydroxyproline 55% in 158 g thyroparathyroidectomized (TPTXed) rats. Calcitonin (25 MRC mU/rat/h) abolished the sodium EDTA-induced increase in hydroxyproline excretion, presumptive evidence that sodium EDTA was acting on bone. To determine whether the changes induced by sodium EDTA are due to lowering of plasma calcium, rats were infused with 4.84 mM ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA), a more specific calcium chelator. EGTA increased the urinary excretion of calcium and phosphorus (P〈0.001) but not hydroxyproline in thyroparathyroidectomized rats. Furthermore, when TPTXed rats were infused with calcium EDTA (4.84 mM Ca2EDTA) in order that ionic calcium concentration would not be altered, hydroxyproline excretion was again markedly increased but phosphorus excretion was decreased by 26%. Since the displacement of the sodium ions in Na2EDTA by calciumin vivo is instantaneous, and since calcium EDTA itself induces collagenolysis, the increase in urinary hydroxyproline excretion due to sodium EDTA cannot be attributed solely to lowering of plasma calcium. From these data two conclusions are drawn. First, sodium EDTA enhances bone breakdown independently of its effect on parathyroid hormone secretion. Second, since bone plays a major role in the maintenance of plasma calcium, interpretation of results should be made with caution in those investigations in which EDTA is used to study calcium homeostasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008209
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  • 7
    Electronic Resource
    Electronic Resource
    Elemental composition of the superficial layer of rat incisor enamel (1974)
    Springer
    Calcified tissue international 16 (1974), S. 139-144 
    Details
    ISSN: 1432-0827
    Keywords: Dental enamel ; Iron ; Calcium ; Phosphorus ; Electron probe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Using electron microprobe analysis, the surface layer of enamel of rat maxillary incisors was found to contain 10–30% Fe. The Ca and P concentrations in different areas of the enamel surface varied inversely with the Fe concentration. The Ca/P weight ratio was 1.8 in areas containing 10% Fe, but decreased to 1.0 in the most Fe-rich areas. The Fe concentration was highest at the prism boundaries, whereas the maximum concentrations of Ca and P were found within the enamel prisms. The concentrations of Fe in rat incisor enamel are among the highest values reported for any mineralized tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008219
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of thyroid hormone on calcium-induced nephrocalcinosis in the jird (Meriones unguiculatus) (1974)
    Springer
    Calcified tissue international 16 (1974), S. 157-162 
    Details
    ISSN: 1432-0827
    Keywords: Hypothyroidism ; Hyperthyroidism ; Nephrocalcinosis ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Meriones unguiculatus (jirds or ‘gerbils’) were rendered hypo- or hyperthyroid by the addition of carbimazole or liothyronine to their diet, and in each of these states were found to be highly susceptible to the nephrotoxic effects of calcium gluconate. Histological studies showed that the pattern of induced nephrocalcinosis was the same in the hypo-, hyper- and eu-thyroid animals and was in the form of calcium deposits both within the cells of the proximal and distal convoluted tubules and in the basement membranes around such tubules. In view of these findings analysis of thyroid function should perhaps be incorporated into the list of diagnostic procedures used in the investigation of patients with nephrocalcinosis and nephrolithiasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008222
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  • 9
    Electronic Resource
    Electronic Resource
    Données histologiques et ultrastructurales sur le calcium thyroïdien (1974)
    Springer
    Calcified tissue international 14 (1974), S. 67-82 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Thyroïd ; Calcitonin ; Hibernation ; Electron microprobe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une quantité importante de calcium se trouve conservée dans la thyroïde de Mammifères soumise à des traitements histologiques qui en eliminent la forme diffusible et les sels minéraux. Sur six espèces examinées, seul l'hibernantElyomis quercinus L. (Lérot) fait exception. Ce calcium, vraisemblablement engagé en combinaisons organiques, se répartit entre la colloïde, les cellules à calcitonine et les noyaux des deux lignées de cellules endocrines. Dans calcitonine, il revêt les grains de sécrétion d'une coque dense. Dans les noyaux, enfin, où sa teneur est très variable, il ne semble pas correspondre en totalité au cation habituellement lié aux acides nucléiques. Il existe, en outre, un calcium diffusible bien représenté dans les espaces intercellulaires et le long des lames basales. La forme diffusible se trouve aussi bien chez l'hibernant que dans les cinq autres espèces.
    Abstract: Zusammenfassung Nach routinemäßiger Aufarbeitung der Säugerschilddrüse für Histologie, bei welcher diffusionsfähiges Calcium und Mineralsalze eliminiert werden, bleiben erhebliche Mengen von Calcium erhalten. Von 6 untersuchten Arten ist der WinterschläferEliomys quercinus L. (Gartenschläfer) die einzige Ausnahme. Das vermutlich organisch gebundene Calcium verteilt sich auf das Kolloid, die Calcitoninzellen und die Zellkerne beider endokriner Zellstämme. Im Kolloid befindet es sich meist in den intrafollikulären Zellen; in den Calcitoninzellen umgibt es die Sekretkörner mit einer dichten Hülle; der Calciumgehalt der Zellkerne unterliegt großen Schwankungen und das Metall scheint nicht nur an die Nukleinsäuren gebunden zu sein. Ferner ist in der Schilddrüse diffusionsfähiges Calcium nachweisbar, das sich sowohl in den Interzellularräumen als auch entlang den Basalmembranen befindet; sowohl die Schilddrüse der winterschlafenden Art als auch die der anderen 5 Spezies enthalten Calcium in dieser Form.
    Notes: Abstract Large quantities of calcium are preserved in the thyroïd of Mammals after removal of the diffusible form and mineral salts by routine histological processes. Among the six species studies, only the hibernating species,Eliomys quercinus (garden dormouse), constitutes an exception. This calcium, probably bound organically, is localised in the colloïd, calcitonin cells and nuclei of both types of endocrine cells. In the colloïd, it is often associated with intrafollicular cells. In calcitonin cells, it densely coats the secretion granules. In nuclei, where the quantities of calcium vary greatly, it does not appear to correspond entirely to the cation usually associated with nuclei acids. Moreover, appreciable amounts of diffusible calcium are present in intercellular spaces and along basal laminae. This diffusible form exists in the hibernating species as well as in the five other species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02060284
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  • 10
    Electronic Resource
    Electronic Resource
    Fluoride and calcification of rat aorta (1970)
    Springer
    Calcified tissue international 6 (1970), S. 173-182 
    Details
    ISSN: 1432-0827
    Keywords: Calcification ; Fluoride ; Aorta ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Le rapport entre le fluor et la calcification de l'aorte a été étudié chez le rat intact et au niveau d'une préparationin vitro de l'aorte thoracique, incubée dans du sérum. La vitamine D3 provoque une augmentation de dix fois la concentration en calcium et une augmentation de douze fois la concentration en phosphate de l'aorte. Le fluor n'a pas d'action sur le dépot du calcium, mais il freine l'augmentation du phosphore de l'aorte des animaux traités à la vitamine D3. Chez les rats témoins, le fluor n'affecte pas l'incorporation du calcium ou du phosphore. La concentration en fluor des aortes des rats, ne recevant que de l'huile de germe de blé par sonde gastrique, n'est pas modifiée par l'administration prolongée de 50 p.p.m. de F à l'eau potable. La vitamine D3 provoque une augmentation de neuf fois la concentration en fluor de l'aorte de rats recevant du fluor dans l'eau potable, lorsqu'on les compare à ceux soumis à la vitamine D3 et à l'eau distillée. Is apparait ainsi que l'exposition prolongée à de l'eau potable fluorée ne favorise pas un début de calcification aortique et n'induit pas de calcification par l'intermédiaire de la vitamine D3. La coloration de von Kossa démontre une calcification intense des aortes de rat recevant de la vitamine D3. Une absence totale de dépôts calciques est notée chez les rats recevant seulement de l'eau distillée. La coloration à la résorcine-fuchsine vert de méthyle, pour la mise en évidence de fibres élastiques, montre une destruction de ces dernières dans les régions de calcification chez les rats recevant la vitamine D3. Ces lésions des fibres élastiques ne sont pas visibles chez les rats ne recevant que du fluor.
    Abstract: Zusammenfassung Wir haben die Wirkung von Fluorid auf der Verkalkung der Aorta anhand folgender zwei Systeme untersucht: bei der Rattein vivo undin vitro an der Aorta thoracica, die in Serum inkubiert wurde. Durch Vitamin D3 wurde bei den Kontrollratten eine 10fache Erhöhung der Calcium-Konzentration und eine 12fache Zunahme des Phosphatgehaltes der Aorta verursacht; Fluorid beeinflußte diese Calcium-Ablagerung nicht, blockierte dagegen die Zunahme des Phosphors in der Aorta der mit Vitamin D3 behandelten Tiere. Bei den mit Maisöl behandelten Ratten beeinträchtigte Fluorid weder die Ablagerung von Calcium noch von Phosphor. Die Fluorid-Konzentration in den Aorten jener Ratten, die nur Maisöl durch die Magensonde erhielten, wurde selbst durch eine langfristige Einnahme von 50 ppm F enthaltendem Trinkwasser nicht beeinflußt. Die Aorten der mit Vitamin D3 behandelten Ratten, deren Trinkwasser Fluorid zugesetzt worden war zeigten im Vergleich zu den Vitamin D3-Ratten, die nur destilliertes Wasser erhielten, eine 9fache Zunahme der Fluoridkonzentration. Somit scheint es, daß Fluorid im Trinkwasser über lange Zeit eingenommen weder eine Verkalkung der Aorta auslöste, noch eine durch Vitamin D3 verursachte Verkalkung zu potenzieren vermochte. Mit der von Kossa-Färbung konnten ausgeprägte Aortenverkalkungen der mit Vitamin D3 behandelten Ratten nachgewiesen werden, wogegen keine pathologischen Kalkablagerungen bei jenen Ratten gefunden wurden, die nur destilliertes Wasser erhielten. Die für elastische Fasern spezifische Resorcin-Fuchsin-Methylgrün-Färbung zeigte Zerstörungen in den Verkalkungszonen bei den mit Vitamin D3 behandelten Ratten, welche aber bei den Tieren, die nur Fluorid erhielten, nicht vorhanden waren. Fluorid schien das histologische Bild der Aorten von Ratten mit Vitamin D3-Gaben nicht zu verändern. Imin vitro-Modell wurden Aortae thoracicae von Ratten während 24 Stdn in Rattenserum inkubiert, welches45Ca sowie 0,14, 0,56 und 1,12 ppm F enthielt. Alle drei Fluoridkonzentrationen hemmten die Aufnahme von45Ca in signifikanter Weise.
    Notes: Abstract The relation between fluoride and calcification of the aorta has been studied in two systems: the intact rat and anin vitro preparation of the thoracic aorta incubated in serum. Vitamin D3 produced a ten-fold increment in calcium concentration and a twelve-fold increase in phosphate levels of the dry aorta. Fluoride did not affect the deposition of calcium, but significantly blocked the increase in phosphorus in the aorta of the vitamin D3-treated animals. In control rats, fluoride did not affect the incorporation of either calcium or phosphorus. The concentration of fluoride in the aortas of rats receiving only corn oil by intubation was not affected by long term exposure to drinking water containing 50 ppm F. Vitamin D3 produced a nine-fold increase in fluoride concentration in the aorta of the rats receiving fluoride in the drinking water when compared to the vitamin D3 rats receiving distilled water. It appears that long-term exposure to fluoride in the drinking water neither initiates calcification in the aorta nor potentiates calcification induced by vitamin D3. Von Kossa stain showed pronounced calcification of the aortas in rats receiving vitamin D3 but none was seen in the rats receiving distilled water alone. Resorcin-fuchsin-methyl green stain for elastic fibers showed destruction in regions of calcification in rats receiving vitamin D3 but not in those receiving fluoride alone. Fluoride did not appear to alter the histological picture seen in the aortas of rats receiving vitamin D3. In thein vitro model, rat thoracic aortas were incubated for 24 hours in rat serum containing45Ca and 0.14, 0.56 and 1.12 ppm F. Fluoride at all levels significantly inhibited45Ca uptake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02196198
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