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  • 1
    ISSN: 1432-0827
    Keywords: Calcium ; Intestine ; Growth ; Cortisol ; Hydroxyproline ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This paper reports the effects of cortisol on intestinal management of calcium and on related changes on bone metabolism. Five groups of 12 rats each fed a standard diet (0.8% Ca) received 2, 6, 16, 32, and 128 mg/kg/day of cortisol hemisuccinate, subcutaneously. After 16 days, intestinal absorption and excretion of Ca were measured with the aid of45Ca. True Ca absorption increased as a function of dose up to 16 mg/kg/day and remained high with the larger doses. Endogenous fecal Ca excretion increased exponentially as a function of the dose from 16 mg/kg/day onwards. Therefore, a dual effect was observed: (a) an increase in true Ca absorption at low cortisol doses (which increased net Ca absorption); and (b) an increase in endogenous fecal Ca excretion at high doses (which reduced net Ca absorption). In no case was a depression of true Ca absorption observed. Growth rate and food conversion efficiency were depressed only with a cortisol dose of 128 mg/kg/day. The urinary excretion of hydroxyproline, pyrophosphate, and aminopolysaccharides decreased with low doses and increased above normal levels with the highest dose. When animals treated with 128 mg/kg/day of cortisol were fed Ca-enriched diets, net Ca absorption improved. Simultaneously, growth rate and food conversion efficiency approached normal values. In these experiments, net absorption of Ca was found to be inversely related to urinary excretion of hydroxyproline. The urinary rate of excretion of hydroxyproline is suggested as an indicator of the effect of a Ca supplement on cortisol affected connective tissue turnover.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0827
    Keywords: Soft tissue calcification ; Arterial calcification ; Lung calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The chemical and crystalline composition of the mineral deposited in ossified arterial and lung tissues of cows affected byenteque seco (enteque ossificans) has been investigated. The arterial calcification precedes that of lung. The latter was observed only in animals with a calcification of the aorta above 150 μmoles Ca per gram of wet tissue. The mineral deposited in arterial and lung tissues appeared to be a poorly crystallized apatite; following incineration the diffraction patterns of carbonate apatite and magnesium whitlockite, respectively, were found.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 4 (1969), S. 39-47 
    ISSN: 1432-0827
    Keywords: Dehydroepiandrosterone ; Calcification ; Embryo ; Tissue Culture ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les modes d'utilisation de glucose, le contenu de calcium et d'hydroxyproline et la densité cellulaire du perioste de les os frontaux d'embryons de poulet de 12 et 13 jours de developpement, cultivés sur coagulum de plasma, se presentant différenment à chaque âge. Cultivés avec sulfate de déhydroèpiandrostérone en concentration 1 mM, les frontaux de 12 jours montrent un synthese augmentée du matrice osseuse, celle de 13 jours se calcifient à une vélocité significativement plus grande que celle des os contôles. Le degré de calcification au quatrième jour de culture measuré par la relation calcium/hydroxyproline, suit un fonction lineáire avec le logarithme des doses de sulfate de dehydroepiandrostérone employées (0.5, 1,0 et 2,0 mM). Les renseignements obtenus indiquent que les frontaux de 13 jours, cultivés “in vitro” constituent modeles experimentaux appropriés pour étudier l'effet des androgénes sur le tissue osseux.
    Abstract: Zusammenfassung Stirnbeine von Hühnerembryonen an ihrem 12. und 13. Entwicklungstag entnommen und in vitro kultiviert zeigen verschiedene Arten der Glucoseverwertung der Periostzellendichte, des Calcium- und Hydroxyprolingehaltes. Wird Dehydroepiandrosteronsulfat dem Medium in einer 1 mM-Konzentration zugegeben, so beteiligen sich die 12tägigen Stirnbeine vorwiegend an der Knochengewebesynthese, während die 13tägigen signifikant stärker verkalken als die Kontrollen. Gemessen an der Calcium/hydroxyprolin Ratio bildet die Verkalkung der 13tägigen Stirnbeine eine lineare Funktion mit den Logarithmen der verwendeten Dosen von Dehydroepiandrosteronsulfat (0,5, 1,0 und 2,0 mM). Das in vitro kultivierte 13tägige Stirnbein schein ein geeignetes Experimentiermodell zur Studie der Dehydroepiandrosteronsulfatwirkung auf das Knochengewebe zu sein, weil es das grundlegende Phänomen (erhöhte Verkalkung) wiedergibt, welches man auch bei mit Androgenen behandelten Menschen und Tieren beobachtet.
    Notes: Abstract Chick embryo frontal bones at 12 and 13 days of development cultivatedin vitro exhibit different patterns of glucose utilization, periosteal cellular density and calcium and hydroxyproline content. When dehydroepiandrosterone sulfate is added to the medium at a concentration 1 mM, 12-day frontals engage primarily in osteoid tissue synthesis while 13-day frontals calcify at a significantly greater rate than controls. Measured with the ratio calcium/hydroxyproline, the calcification of 13-day frontals follows a linear function with the logarithm of the doses of dehydroepiandrosterone sulfate employed (0.5, 1.0 and 2.0 mM). The 13-day frontal bone cultivatedin vitro seems to be an adequate experimental model for the study of the effects of dehydroepiandrosterone sulfate on bone tissue because it reproduces the basic phenomenon (increased calcification) observed in man and animals treated with androgens.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 16 (1974), S. 153-155 
    ISSN: 1432-0827
    Keywords: Galactose ; Glucose-6-phosphate dehydrogenase ; Collagen ; Galactose-1-phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The bone tissue levels of galactose-1-P have been found to be a function of the concentration of galactose in blood.In vitro, the glucose-6-phosphate dehydrogenase (bone isoenzyme) was competitively inhibited by galactose-1-P. Galactose or galactitol were found ineffective. Therefore, the previously reported depressed activity of bone glucose-6-phosphate dehydrogenase in galactose-fed rats should be interpreted as mediated by galactose-1-P. When compared with their controls, galactose-fed rats showed a significantly lower growth rate which was reflected in a lower bone collagen content and in a lower percentage of salt soluble collagen.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 12 (1973), S. 8-15 
    ISSN: 1432-0827
    Keywords: Insulin ; Bone ; Calcium ; Resorption ; Orthophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'administration d'insuline cristallisée à des rats thyroparathyroidectomisés provoque une augmentation de la calcémie et de la phosphorémie. Le calcium plasmatique s'élève de façon linéaire entre 31 et 250 m Unités d'insuline/100 g de poids corporel. La courbe obtenue n'est guère différente de celle obtenue par extrait parathyroidien. L'administration simultanée d'insuline et d'extrait parathyroidien à des rats thyro-parathyroidectomisés agit sur la calcémie et la phosphorémie par un effet additif. Lorsque des os frontaux d'embryons de poulet sont cultivésin vitro en présence d'insuline cristallisée, le taux de résorption augmente. L'insuline augmente le taux de consommation en glucose des explants et induit une accumulation de citrate dans le milieu de culture. L'insuline stimule donc la résorption osseuse.
    Abstract: Zusammenfassung Der Plasmagehalt an Calcium und Phosphor bei thyroparathyreoidektomierten Ratten wurde durch die Verabreichung von kristallinem Insulin erhöht. Das Plasmacalcium verhielt sich zwischen 31 und 250 m Einheiten Insulin pro 100 g Körpergewicht linear. Die Steigung der erhaltenen Kurve ist nicht signifikant verschieden von derjenigen, die nach Parathyreoidea-Extrakt erhalten wird. Die gleichzeitige Verabreichung von Insulin und Parathyreoidea-Extrakt von thyroparathyreoidektomierten Ratten hatte eine kumulative Wirkung auf den Gehalt von Calcium und Phosphor im Plasma. Wenn Stirnbeine von Kükenembryos mit kristallinem Insulinin vitro kultiviert wurden, erhöhte sich die Resorptionsrate. Das Insulin steigerte den Glucoseverbrauch der Explantate und verursachte eine Anreicherung von Citrat im Kulturmedium. Die Ergebnisse deuten auf eine Stimulation der Knochenresorption durch Insulin.
    Notes: Abstract the administration of crystalline insulin to thyroparathyroidectomized rats raised their calcium and phosphorus plasma levels. The plasma calcium gave a linear response between 31 and 250 mU of insulin/100 g body weight. The slope obtained is not significantly different from that obtained with parathyroid extract. The simultaneous administration of insulin and parathyroid extract to thyroparathyroidectomized rats affected the calcium and phosphorus plasma levels in an additive fashion. When chick embryo frontal bones were cultivatedin vitro with crystalline insulin the rate of resorption increased. Insulin increased the rate of glucose consumption by the explants and induced the accumulation of citrate in the culture medium. It is concluded that insulin stimulates bone resorption.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 6 (1970), S. 133-142 
    ISSN: 1432-0827
    Keywords: Testosterone ; Dehydroepiandrosterone ; Glucosephosphate-dehydrogenase ; Glucose ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les effets des androgènes (déhydroépiandrostérone et testostérone) sur le métabolisme des hydrates de carbone ont été étudiés en utilisant deux modèles expérimentaux. Le premier fait appel à la culturein vitro d'os embryonnaires d'oiseaux. Dans le deuxième modèle, on utilise des os non embryonnaires de mammifères, en cours d'ossification enchondralein vivo. Dans les deux cas, on note une augmentation de l'activité de la glucose-6-phosphate déhydrogénase et une oxydation différente de la glucose-1-14C et glucose-6-14C. Ces faits indiquent un changement dans le métabolisme du glucose allant vers la voie oxydative directe. En plus, le traitement provoque une hyperplasie de la couche hypertrophique dans l'épiphyse osseuse chez les souris prépubères.
    Abstract: Zusammenfassung Es wurden die Wirkungen von Androgenen (Dehydroepiandrosteron und Testosteron) auf den Kohlenhydratumsatz von Knochen mittels 2 experimenteller Modelle untersucht: einerseits anin vitro gezüchteten Bindegewebsknochen von Hühnerembryonen und andererseitsin vivo an nichtembryonalen Säugetierknochen mit endochondraler Ossifikation. In beiden Modellen läßt die Aktivitätszunahme der Glucose-6-phosphat-dehydrogenase und die unterschiedliche Oxydation von Glucose-1-14C und Glucose-6-14C eine Verschiebung des Glucosemetabolismus gegen den direkten oxydativen Abbau vermuten. Weiterhin erzeugt eine Behandlung mit diesen Hormonen eine Hyperplasie der hypertrophen Zellschicht an der Epiphysenplatte von vorpubertären Mäusen.
    Notes: Abstract An investigation on the effects of androgens (dehydroepiandrosterone and testosterone) on the carbohydrate metabolism of bone was carried out with two experimental models: avian embryonic membranous bone cultivatedin vitro, and mammal non-embryonic bone of endochondral ossificationin vivo. In both models, the increase in glucose-6-phosphate dehydrogenase activity and the differential oxidation of glucose-1-14C and glucose-6-14C suggest a shift in glucose metabolism toward the direct oxidative pathway. In addition, treatment with these hormones produces hyperplasia of the hypertrophic cell layer at the epiphyseal plate of prepubertal mice.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 60 (1997), S. 86 -89 
    ISSN: 1432-0827
    Keywords: Key words: Monofluorophosphate — Protein-binding —α2-Macroglobulin — C3.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. After administering an oral dose of monofluorophosphate (MFP) to human beings or rats, a fraction of the drug appears in plasma that is bound to proteins, establishing a previously undetected compartment of nondiffusible fluoride. This article documents experiments performed in vitro, describing the binding of MFP to two plasma globulins: α2-macroglobulin and C3 (a β-globulin). MFP binds irreversibly to these proteins through a stable bond. MFP binds to purified α2-macroglobulin or to C3 with a molar ratio MFP: protein close to unity. MFP binding reduces significantly the biological activity of these proteins, which share in common a macrocyclic 4-residue ring thiolactone (Cys—Gly—Glu—Glu). The binding site of MFP is as yet unknown. Protein-bound MFP appeared in the plasma of volunteers during the 5–7 hours following intake. Peak concentration of protein-bound MFP and maximal reduction of α2-macroglobulin activity was observed 2 hours after intake. Clearance of protein-bound MFP coincided with the return of α2-macroglobulin to basal levels.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    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.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 14 (1974), S. 169-175 
    ISSN: 1432-0827
    Keywords: Galactose ; Glucose-6-phosphate ; Resorption ; Pyrophosphate ; Hydroxyproline ; Alkaline phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'effet du galactose sur le métabolisme osseux est étudié en soumettant de jeunes rats à un régime semi-synthétique contenant 35% de ce monosaccharide. Les animaux témoins reçoivent le même régime sans galactose, avec du glucose. L'effet d'une consommation de Ca−P, normal et faible, est étudié chez les témoins et les groupes soumis au galactose. La glucose-6-phosphate deshydrogénase osseuse est inhibée lorsque le galactose s'accumule dans les tissues. L'excrétion urinaire de calcium, pyrophosphate, aminopolysaccharides, hydroxyproline en phosphatase alcaline plasmatique (isoenzyme osseuse) est augmentée de façon significative par rapport aux témoins. Les animaux, recevant du galactose avec un régime faible en Ca et P, présentent une balance négative en Ca, due surtout à un excretion fécale plus élevée que les apports. Un rapport inverse est observé entre la balance calcique et l'ingestion alimentaire. L'effet nocif du galactose sur le métabolisme du calcium pourrait agir par l'intermédiaire d'une action sur les cellules osseuses et les fonctions rénales et intestinales, en rapport, peut-être, avec un trouble inconnu du métabolisme hydro-carboné.
    Abstract: Zusammenfassung Die Wirkung von Galaktose auf den Knochenstoffwechsel junger Ratten wurde untersucht, indem diese eine semisynthetische Nahrung erhielten, welche 35% dieses Monosaccharids enthielt. Kontrolltiere erhielten dieselbe Nahrung ohne Galaktose, aber mit Glukose. Die Kontrollgruppe und die Gruppe mit Galaktosenahrung erhielten eine niedrige und eine normal Ca−P-Einnahme. Die Glukose-6-Phosphat-Dehydrogenase des Knochens wurde gehemmt, wenn Galaktose im Gewebe zunahm. Die Urinausscheidung von Calcium, Pyrophosphat, Aminopolysacchariden, Hydroxyprolin und alkalischer Phosphatase des Plasmas (Knochen-Isoenzym) war signifikant höher als bei den Kontrollen. Die Tiere mit Galaktosezusatz und niedriger Ca−P-Aufnahme zeigten eine negative Calciumbilanz, die hauptsächlich durch eine fäkale Ausscheidung bedingt war, welche höher war als die Einnahme. Es wurde eine umgekehrt proportionale Beziehung zwischen Calciumbilanz und Nahrungseinnahme beobachtet. Die nachteilige Wirkung von Galaktose auf den Calciumstoffwechsel mag von einer Wirkung auf die Knochenzellen und auf die Nieren- und Darmfunktion herrühren, vielleicht im Zusammenhang mit einer noch unbestimmten Störung des Kohlenhydratstoffwechsels.
    Notes: Abstract The effect of galactose on bone metabolism was studied by feeding young rats a semisynthetic diet containing 35% of this monosaccharide. Control animals received the same diet without galactose but with glucose. Both a low, and a normal, Ca−P intake were studied in the control and galactose fed groups. Bone glucose-6-phosphate dehydrogenase was inhibited as galactose accumulated in the tissue. Urinary excretion of calcium, pyrophosphate, aminopolysaccharides, hydroxyproline and plasma alkaline phosphatase (bone isoenzyme) were significantly increased above control levels. Galactose fed animals on a low Ca and P diet showed a negative Ca balance, primarily due to a fecal excretion which was greater than intake. An inverse relationship between calcium balance and food intake was observed. The adverse effect of galactose on calcium metabolism may be mediated by an effect on bone cells and on renal and intestinal function, related perhaps to an as yet non-defined disturbance of carbohydrate metabolism.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 2 (1968), S. 133-144 
    ISSN: 1432-0827
    Keywords: Dehydroepiandrosterone ; Testosterone ; Embryo ; Tissue culture ; Frontal bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les os frontaux d'embryons de poulet, de 12 jours de développement, cultivés sur coagulum de plasma avec sulfate de déhydroépiandrostérone (DS) en concentration 1 mM, montrent hyperplasie du périoste et synthèse augmentée du matrice osseuse. Ces phénomenes ne son pas vus quand on emploie les os frontaux de 11 jours de développement. La testostérone produit les mêmes effets que le DS. Le deux steroïdes semblent agir directement sur l'os selon on peut le déduire des conditions expérimentales. L'activité de la phosphatase alcaline des frontaux d'embryons de poulet de 12 jours de développement est augmentée de manière significative quand les rudiments son cultivés dans un milieu qui contient DS ou testostérone. Dans ces deux cas: a) on peut révéler l'activation de l'enzyme par des expériences de cinétique enzymatique et b) les vélocités maximes apparantes ont une grande correlation avec le logarithme des doses employées. Quand les deux steroïdes son essayés en conditions semblables, les deux produisent la même augmentation de l'activité phosphatasique.
    Abstract: Zusammenfassung Wenn Stirnknochen von 12 Tage alten Hühnerembryonen in vitro auf koaguliertem Plasma mit Zusatz von 1 mM Dehydroepiandrosteronsulfat gezüchtet werden, so zeigen sie eine Hyperplasie des Periostes und eine erhöhte Synthese des Osteoidgewebes. Diese Erscheinung trifft nicht zu, ween 11 tägige Stirnknochen in gleicher Weise gezüchtet werden. Mit Testosteron werden gleiche Effekte wie mit Dehydroepiandrosteronsulfat erzielt. Aus den gewählten Versuchsverhältnissen kann abgeleitet werden, daß beide Steroide direkt auf den Knochen zu wirken scheinen. Die Aktivität der alkalischen Phosphatase im Stirnknochen des 12 Tage alten Hühnerembryos ist signifikant erhöht, wenn die Knochenansätze in einem Dehydroepiandrosteron oder Testosteron enthaltenden Medium gezüchtet werden. In beiden Fällen ergeben enzymkinetische Untersuchungen einerseits eine Aktivierung des Enzyms, andererseits eine gute Korrelation der erhaltenen scheinbaren Maximalgeschwindigkeiten mit dem Logarithmus der verwendeten Dosen. Bei gleichzeitiger Prüfung bewirkten beide Steroide gleichzeitig eine ähnliche Aktivitätszunahme der alkalischen Phosphatase.
    Notes: Abstract Chick embryo frontal bones at 12 days of development, cultivated in vitro on plasma clots with dehydroepiandrosterone sulfate in a concentration 1mM, exhibit periosteal hyperplasia and increased synthesis of osteoid tissue. These phenomena are not observed when 11-day frontals are cultivated in similar conditions. Testosterone produces the same effects as dehydroepiandrosterone sulfate. Both steroids seem to act directly on bone as can be inferred from the experimental conditions employed. The alkaline phosphatase activity of chick embryo frontal bones at 12 days of development is significantly increased when the rudiments are cultivated in a medium containing dehydro-epiandrosterone or testosterone. In both cases a) enzyme kinetics experiments revealed that there is activation of the enzyme and b) the apparent maximum velocities obtained are hihgly correlated with the logarithm of the doses employed. When assayed simultaneously, both steroids were found equally active in promoting the increase in alkaliue phosphatase activity.
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