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  • 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate  (6)
  • Calcium  (5)
  • Collagen  (5)
  • Springer  (15)
  • Blackwell Publishing Ltd
  • Cell Press
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2010-2014  (6)
  • 2005-2009
  • 1965-1969  (9)
  • 1960-1964
  • 2011  (1)
  • 2010  (5)
  • 1968  (9)
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  • 2010-2014  (6)
  • 2005-2009
  • 1965-1969  (9)
  • 1960-1964
Year
  • 1
    Publication Date: 2017-04-04
    Description: Increased atmospheric carbon dioxide concentration provided warmer atmospheric temperature and higher atmospheric water vapor content, but not necessarily more precipitation. A set of experiments performed with a state-of-the-art coupled general circulation model forced with increased atmospheric CO2 concentration (2, 4 and 16 times the present-day mean value) were analyzed and compared with a control experiment to evaluate the effect of increased CO2 levels on monsoons. Generally, the monsoon precipitation responses to CO2 forcing are largest if extreme concentrations of carbon dioxide are used, but they are not necessarly proportional to the forcing applied. In fact, despite a common response in terms of an atmospheric water vapor increase to the atmospheric warming, two out of the six monsoons studied simulate less or equal summer mean precipitation in the 16xCO2 experiment compared to the intermediate sensitivity experiments. The precipitation differences between CO2 sensitivity experiments and CTRL have been investigated specifying the contribution of thermodynamic and purely dynamic processes. As a general rule, the differences depending on the atmospheric moisture content changes (thermodynamic component) are large and positive, and they tend to be damped by the dynamic component associated with the changes in the vertical velocity. However, differences are observed among monsoons in terms of the role played by other terms (like moisture advection and evaporation) in shaping the precipitation changes in warmer climates. The precipitation increase, even if weak, occurs despite a weakening of the mean circulation in the monsoon regions (‘‘precipitation-wind paradox’’). In particular, the tropical east-west Walker circulation is reduced, as found from velocity potential analysis. The meridional component of the monsoon circulation is changed as well, with larger (smaller) meridional (vertical) scales.
    Description: Published
    Description: 83-101
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: carbon dioxide forcing ; monsoon precipitation ; coupled GCMs ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2021-06-25
    Description: A multi-model set of atmospheric simulations forced by historical sea surface temperature (SST) or SSTs plus Greenhouse gases and aerosol forcing agents for the period of 1950–1999 is studied to identify and understand which components of the Asian–Australian monsoon (A–AM) variability are forced and reproducible. The analysis focuses on the summertime monsoon circulations, comparing model results against the observations. The priority of different components of the A–AM circulations in terms of reproducibility is evaluated. Among the subsystems of the wide A–AM, the South Asian monsoon and the Australian monsoon circulations are better reproduced than the others, indicating they are forced and well modeled. The primary driving mechanism comes from the tropical Pacific. The western North Pacific monsoon circulation is also forced and well modeled except with a slightly lower reproducibility due to its delayed response to the eastern tropical Pacific forcing. The simultaneous driving comes from the western Pacific surrounding the maritime continent region. The Indian monsoon circulation has a moderate reproducibility, partly due to its weakened connection to June–July–August SSTs in the equatorial eastern Pacific in recent decades. Among the A–AM subsystems, the East Asian summer monsoon has the lowest reproducibility and is poorly modeled. This is mainly due to the failure of specifying historical SST in capturing the zonal land-sea thermal contrast change across the East Asia. The prescribed tropical Indian Ocean SST changes partly reproduce the meridional wind change over East Asia in several models. For all the A–AM subsystem circulation indices, generally the MME is always the best except for the Indian monsoon and East Asian monsoon circulation indices.
    Description: Published
    Description: 1051-1068
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: CLIVAR C20C ; Asian-Australian monsoon circulation ; AGCM ; Reproducibility ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2017-04-04
    Description: Increased atmospheric carbon dioxide concentration provided warmer atmospheric temperature and higher atmospheric water vapor content, but not necessarily more precipitation. A set of experiments performed with a state-of-the-art coupled general circulation model forced with increased atmospheric CO2 concentration (2, 4 and 16 times the present-day mean value) were analyzed and compared with a control experiment to evaluate the effect of increased CO2 levels on monsoons. Generally, the monsoon precipitation responses to CO2 forcing are largest if extreme concentrations of carbon dioxide are used, but they are not necessarly proportional to the forcing applied. In fact, despite a common response in terms of an atmospheric water vapor increase to the atmospheric warming, two out of the six monsoons studied simulate less or equal summer mean precipitation in the 16xCO2 experiment compared to the intermediate sensitivity experiments. The precipitation differences between CO2 sensitivity experiments and CTRL have been investigated specifying the contribution of thermodynamic and purely dynamic processes. As a general rule, the differences depending on the atmospheric moisture content changes (thermodynamic component) are large and positive, and they tend to be damped by the dynamic component associated with the changes in the vertical velocity. However, differences are observed among monsoons in terms of the role played by other terms (like moisture advection and evaporation) in shaping the precipitation changes in warmer climates. The precipitation increase, even if weak, occurs despite a weakening of the mean circulation in the monsoon regions(‘‘precipitation-wind paradox’’). In particular, the tropical east-west Walker circulation is reduced, as found from velocity potential analysis. The meridional component of the monsoon circulation is changed as well, with larger (smaller) meridional (vertical) scales.
    Description: In press
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: carbon dioxide forcing ; monsoon precipitation ; coupled model experiments ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2017-04-04
    Description: In this chapter, a review is given of progress to date on an intercomparison project designed to compare and evaluate the ability of climate models to generate tropical cyclones, the Tropical Cyclone climate Model Intercomparison Project(TC-MIP). Like other intercomparison projects, this project aims to evaluate climate models using common metrics in order to make suggestions regarding future development of such models.
    Description: Published
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: restricted
    Keywords: Tropical Cyclones ; general circulation models ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 5
    Publication Date: 2017-04-04
    Description: This study investigates the possible changes that the greenhouse global warming might generate in the characteristics of the tropical cyclones (TCs). The analysis has been performed using scenario climate simulations carried out with a fully coupled high-resolution global general circulation model. The capability of the model to reproduce a reasonably realistic TC climatology has been assessed by comparing the model results from a simulation of the 20th Century with observations. The model appears to be able to simulate tropical cyclone-like vortices with many features similar to the observed TCs. The simulated TC activity exhibits realistic geographical distribution, seasonal modulation and interannual variability, suggesting that the model is able to reproduce the major basic mechanisms that link the TC occurrence with the large scale circulation. The results from the climate scenarios reveal a substantial general reduction of the TC frequency when the atmospheric CO2 concentration is doubled and quadrupled. The reduction appears particularly evident for the tropical North West Pacific (NWP) and North Atlantic (ATL). In the NWP the weaker TC activity seems to be associated with a reduced amount of convective instabilities. In the ATL region the weaker TC activity seems to be due to both the increased stability of the atmosphere and a stronger vertical wind shear. Despite the generally reduced TC activity, there is evidence of increased rainfall associated with the simulated cyclones. Despite the overall warming of the tropical upper ocean and the expansion of warm SSTs to the subtropics and mid-latitudes, the action of the TCs remains well confined to the tropical region and the peak of TC number remains equatorward of 20° latitude in both Hemispheres. An extended version of this work is in available on Journal of Climate (Gualdi et al.,2008 - DOI:10.1175/2008JCLI1921.1)
    Description: Published
    Description: 287-321
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: open
    Keywords: climate ; tropical cyclones ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 6
    Publication Date: 2017-04-04
    Description: Understanding the historical and future response of the global climate system to anthropogenic emissions of radiatively active atmospheric constituents has become a timely and compelling concern. At present, however, there are uncertainties in: the total radiative forcing associated with changes in the chemical composition of the atmosphere; the effective forcing applied to the climate system resulting from a (temporary) reduction via ocean-heat uptake; and the strength of the climate feedbacks that subsequently modify this forcing. Here a set of analyses derived from atmospheric general circulation model simulations are used to estimate the effective and total radiative forcing of the observed climate system due to anthropogenic emissions over the last 50 years of the twentieth century. They are also used to estimate the sensitivity of the observed climate system to these emissions, as well as the expected change in global surface temperatures once the climate system returns to radiative equilibrium. Results indicate that estimates of the effective radiative forcing and total radiative forcing associated with historical anthropogenic emissions differ across models. In addition estimates of the historical sensitivity of the climate to these emissions differ across models. However, results suggest that the variations in climate sensitivity and total climate forcing are not independent, and that the two vary inversely with respect to one another. As such, expected equilibrium temperature changes, which are given by the product of the total radiative forcing and the climate sensitivity, are relatively constant between models, particularly in comparison to results in which the total radiative forcing is assumed constant. Implications of these results for projected future climate forcings and subsequent responses are also discussed.
    Description: Published
    Description: 1461-1475
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: atmospheric general circulation models ; climate forcing ; climate sensitivity ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Electronic Resource
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    Calcified tissue international 2 (1968), S. 296-298 
    ISSN: 1432-0827
    Keywords: Calcium ; Lipid ; Bacteria ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé On a fait ce travail pour determiner si le facteur responsable pour la liaison de calcium par un calcifableBacterionema matruchotii est dans la fraction lipide de la cellule. Des cellules congelees et sechees ont ete extraites par le chloroform-methanol. La fraction de chloroform-methanol, les cellules extraites et les cellules non traitees ont ete examinees pour la liaison de calcium. La fraction du chloroform-methanol et les cellules non traitees avaient la liaison de calcium. Les cellules extraites n'en avaient pas.
    Abstract: Zusammenfassung Diese Arbeit wurde durchgeführt um festzustellen, ob sich der Faktor für die Calcium-bindung, durch das calcifizierendeBacterionema matruchotii, in der Lipoidfraktion befindet. Die lyophiilisierten Zellen wurden mit Chloroform-Methanol extrahiert. Die Chloroform-Methanol-Fraktion, die extrahierten Zellen, sowie die nicht behandelten Zellen wurden auf eine Calciumbindung hin untersucht. Die Chloroform-Methanol-Fraktion und die nicht behandelten Zellen demonstrierten eine Calciumbindung. Die extrahierten Zellen hingegen nicht.
    Notes: Abstract This work was done to determine whether the factor responsible for calcium binding by a calcifiableBacterionema matruchotii is in the lipid fraction of the cell. Freeze-dried cells were extracted with chloroform-methanol. The chloroform-methanol fraction, the extracted cells and untreated cells were examined for calcium binding. The chloroform-methanol fraction and the untreated cells bound calcium. The extracted cells did not.
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  • 8
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    Calcified tissue international 2 (1968), S. 67-76 
    ISSN: 1432-0827
    Keywords: Calcergy ; Calciphylaxis ; Calcium ; Metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Chez le rat, des expériences ont montré que, sauf de rares exceptions, les calcifications produites au site d'injection d'acétate de plomb, de chlorure de cérium, chlorure de calcium ou de permanganate de potassium sont complètement prévenues ou fortement inhibées par l'application locale simultanée de provocateurs calciphylactiques, mais non par des agents non provocateurs. Malgré quelques exceptions (attribuées à des interrelations chimiques spécifiques entre certaines des substances utilisées), cette curieuse corrélation entre l'efficacité calciphylactique provocatrice et le pouvoir anticalcergique est, d'après le test χ2, hautement significative (P〈0,001).
    Abstract: Zusammenfassung Nach subcutaner Injektion von Bleiacetat, Ceriumchlorid, Calciumchlorid oder Kaliumpermanganat tritt an der Injektionsstelle eine starke Verkalkung auf. Bis auf sehr wenige Ausnahmen kann diese durch gleichzeitige lokale Anwendung von calciphylaktischen Provokatoren verhütet oder weitgehend unterdrückt werden. In dieser Beziehung sind nicht provolatorisch wirkende Stoffe inaktiv. Trotz der wenigen Ausnahmen (die wahrscheinlich auf spezifische, chemische Wechselwirkungen zwischen manchen der untersuchten Substanzen beruhen) ist dieser merkwürdige Zusammenhang zwischen calciphylaktisch provozierender und anticalcergischer Aktivität, nach dem χ2-Test berechnet, statistisch hochsignifikant (P〈0,001).
    Notes: Abstract Experiments on rats indicate that, with very few exceptions, the calcification which occurs at subcutaneous sites of treatment with lead acetate, cerium chloride, calcium chloride or potassium permanganate is completely blocked or severely inhibited by simultaneous topical application of calciphylactic challengers but not of non-challengers. Despite the few exceptions (which are thought to depend upon specific chemical interactions between some of the compounds tested) this singular correlation between calciphylactic challenging and anticalcergic potency, is highly significant by the Chi-square-test (P〈0.001).
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  • 9
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    Calcified tissue international 2 (1968), S. 343-352 
    ISSN: 1432-0827
    Keywords: Nucleation ; Mineralization ; Bone ; Collagen ; Apatite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Nous avons utilisé de la collagène d'os de mounton et de tendons de queues de rats et des cristaux d'apatite pour étudier dans un système modèle la catalysation de la nucléation et la déposition de minéral dans un tampon métastabile. La collagène d'os de mouton se trouvait être un bon catalysateur, tandis que des expériences antérieures ont démontré que la collagène de tendons de queues de rats était un catalysateur très faible. Le phase rapide de la déposition de l'apatite dans la collagène se termine aussitôt que le contenu du minéral a attaint au plus 50 à 60 pour cent, bien que la supersaturation du tampon est encore bien èlevée. Les résultats montrent que dans un tel système modèle la quantité du depôt minéral est réglée par des facteurs semblables à ceux qui opèrent pendant la calcification biologique.
    Abstract: Zusammenfassung Kollagen aus Schafsknochen und Rattenschwanzsehnen und Apatitkeime wurden verwendet in einem Modell-System zur Untersuchung der katalytischen Nukleation und der Fällung von Mineral in einem metastabilen Calciumphosphatpuffer. Kollagen aus Schafsknochen war ein guter Katalysator für die Nukleation, während in früheren Versuchen sich herausstellte, daß Rattenschwanzkollagen ein ganz schlechter Katalysator ist. Die schnelle Phase der Apatitfällung im Kollagen war beendet, wenn der Mineralgehalt bis zu 50–60% angestiegen war, obwohl der Puffer noch stark übersättigt war. Die Resultate weisen daraufhin, daß die Menge des gefällten Minerals in einem solchen Modell-System von ähnlichen Faktoren reguliert wird wie die biologische Verkalkung.
    Notes: Abstract Sheep bone collagen, rat tail tendon collagen and apatite seeds were used in a model system to study nucleation catalysis and mineral deposition in a metastable calcification buffer. Sheep bone collagen was shown to be a good nucleation catalyst, while earlier experiments have shown that rat tail tendon collagen was a very poor catalyst. The rapid phase of apatite deposition in the collagen was terminated as soon as a mineral content of not more than 50–60 per cent was reached, although the buffer was still highly supersaturated. The results suggest that the amount of mineral deposited in such a model system is regulated by factors similar to those operating in biological calcification.
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  • 10
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    Calcified tissue international 2 (1968), S. 1-19 
    ISSN: 1432-0827
    Keywords: Collagen ; Hydroxyapatite ; Keratin ; Enamel ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
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  • 11
    ISSN: 1432-0827
    Keywords: Collagen ; 14C-Proline ; Growth ; Bone ; Teeth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Zusammenfassung Das Ausmaß, bis zu welchem Austausch- und Wiederverwendungsprozesse der mineralen Tracer die Messungen des mineralen Skelett-Auf- und Abbaues beeinflussen können, wurde ausgewertet; zu diesem Zweck wurde die Geschwindigkeit des Auftretens und Verschwindens von85Sr und von14C-Prolin-Hydroxyprolin in Knochen und Zähnen von wachsenden Ratten während der 12 auf die simultane parenterale Injektion dieser Tracer folgenden Tage verglichen. Der Ausdruck für die relative Geschwindigkeit des Kollagen-Auf- und Abbaues, bei welchem im Gegensatz zum Mineralmetabolismus kein Mitwirken des Austauschphänomens vermutet wird, basiert auf der Umwandlung von14C-Prolin zu14C-Hydroxyprolin; die spezifische Aktivität des letzteren wurde bestimmt. Aus der spezifischen Aktivität des Minerals sowie jener des Kollagens konnten die Geschwindigkeit und die Art des Wachstums der untersuchten Proben ersehen werden, d.h.schnelles Wachstum und ein kurzes Zeitintervall zwischen Bildung und Resorption des Gewebes imKnochen der Metaphyse, die auch die knorpelige Wachstumsplatte enthält, und andererseitslangsames Wachstum und längeres Zeitintervall (länger als die 12 Tage des Experimentes) zwischen Bildung und Resorption des Gewebes imKnochen der Diaphyse und in den Schneidezähnen. Immerhin fiel die spezifische Aktivität des Kollagen/Mineral-Anteils im Knochen der Metaphyse während dem 4–12tägigen Zeitintervall auf die Hälfte, im Gegensatz zum Knochen der Diaphyse und der Schneidezähne, bei welchen während dieser Zeitspanne kein Unterschied in diesem Verhältnis beobachtet wurde. Diese Ergebnisse zeigen, daß Kollagen in der Wachstumszone der Metaphyse durch Resorption verschwindet, bevor es ganz mineralisiert ist, und daß der Austausch ein relativ unwichtiger Faktor in der Kinetik auf lange Sicht des Knochenminerals ist.
    Notes: Abstract The extent to which exchange and reutilization processes of mineral tracers affect skeletal mineral accretion and resorption measurements was evaluated by comparing the rates of appearance and disappearance of85Sr and14C-proline-hydroxyproline in bones and teeth in growing rats for 12 days following simultaneous parenteral injection of these tracers. Expressions for the relative rates of collagen synthesis and breakdown, which unlike mineral metabolism are considered not to be complicated by exchange phenomena, were based on14C-proline conversion to14C-hydroxyproline; the specific activity of the latter was determined. Both the mineral and the collagen specific activities reflected the rates and patterns of growth of the samples assayed; rapid growth and a short interval of time between formation and resorption of tissue in themetaphyseal bone which contains the cartilagineous growth plate, slow growth and an interval of time between formation and resorption of tissue indiaphyseal bone and incisor teeth which is longer than the 12 days of the experiment. However, in metaphyseal bone the specific activity collagen/mineral ratio dropped by one half during the 4–12 day interval in contrast to diaphyseal bone and incisor teeth in which no change in this ratio was observed during this period of time. The data indicate that collagen in the metaphyseal growth zone is removed by resorption before it has become fully mineralized, and that exchange is a relatively unimportant factor in the long term kinetics of bone mineral.
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  • 12
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    Calcified tissue international 2 (1968), S. 253-261 
    ISSN: 1432-0827
    Keywords: Calcium ; Ion ; Binding ; Chondroitin ; Cartilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La liaison du calcium par le sulfate de chondroitin C a été étudiée en utilisant des méthodes biologiques et physicochimiques pour la détermination quantitative du calcium ionique. Les valeurs moyennes pour logK j, le logarithme de la constante de formation non corrigée d'un complexe calcium-sulfate de chondroitin C, sont 1,64 par la technique de cœur de grenouille, 1,55 par la méthode de murexide, 1,39 par l'ultrafiltration et 1,04 par l'électrode sélective du calcium. L'ordre de grandeur de ces valeurs suggèrent que le sulfate de chondroitin C a une capacité de liaison pour calcium relativement élevée, mais les valeurs calculées pour un paramètre d'échangeK p indiquent que le calcium a une affinité faible pour le polysaccharide.
    Abstract: Zusammenfassung Die Bindung von Calcium mit Chondroitinsulfat C wurde untersucht mittels biologischer und physikalisch-chemischer Methoden für die quantitative Bestimmung des ionischen Calciums. Im Durchschnitt ergab logK j, der Logarithmus der unkorrigierten Formationskonstante für einen Calciumchondroitinsulfatkomplex, 1,64 mit der Technik des Froschherzens, 1,55 mit der Murexidmethode, 1,39 mittels Ultrafiltration und 1,04 mit den Calciumselektiven Elektroden. Die Größe dieser Werte zeigt, daß Chondroitinsulfat eine relativ hohe Bindungskapazität für Calcium hat, die berechneten Werte für einen AustauschparameterK p jedoch, daß Calcium eine kleine Affinität für Polysaccharide hat.
    Notes: Abstract The binding of calcium by chondroitin sulfate C was studied by employing biological and physicochemical methods for the quantitative determination of ionic calcium. Mean values for logK j, the logarithm of the uncorrected formation constant for a calcium-chondroitin sulfate complex, were 1.64 with the frog heart technique, 1.55 with the murexide method, 1.39 with ultrafiltration and 1.04 with the calcium selective electrode. The magnitude of these values suggests that chondroitin sulfate has a relatively high binding capacity for calcium, but calculated values for an exchange parameterK p indicate that calcium has a low affinity for the polysaccharide.
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  • 13
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    Calcified tissue international 2 (1968), S. 301-313 
    ISSN: 1432-0827
    Keywords: Calcium ; Absorption ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
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  • 14
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    Calcified tissue international 2 (1968), S. 20-29 
    ISSN: 1432-0827
    Keywords: Bone Atrophy ; Bone Resorption ; Calcium ; Collagen ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Atrophie osseuse d'immobilisation était induite par section de la plexus brachial et/ou désarticulation de la coude. Après 9 bis 12 semaines de désuétude huméri intactes furent examinés par rayons X et leur qualités physiques déterminés. Les humérientiers furent isolés, dégraissés, desséchés au poids constant, et leur teneur en cendre d'os et collagène déterminés. Huit des 10 huméri immobilisés monstrérent radiodensité diminué. La jambe inusitée monstra perte parallèle en poids sec et poids sans gras (−23.2%), en collagène (−25.3%), et en cendre d'os (−26.1%) en comparaison de la jambe normale. Les données monstrèrent que la portion plus grande du tissu osseux perdu en atrophie osseuse d'immobilisation est remplacée par de l'eau, du gras, et des autres matériels organiques inconnus plutôt que par tissu fibreux, et que collagène est perdu en proportion du minéral. La perte proportionellement plus grande du collagène et de la cendre d'os que du poids sec et poids san gras semble dû à une augmentation du matériel organique, non-collagéne, non-lipide, kprobablement protéine.
    Abstract: Zusammenfassung Immobilisations-Knochenatrophie wurde in 10 erwachsenen Hunden herbeigeführt durch Brachialplexusschnitt und/oder Ellenbogenexartikulation. Nach 9–12 Wochen der Immobilisation wurden die intakten Humeri unter Röntgenstrahlen untersucht und ihre physischen Eigenschaften bestimmt. Derintakte Humerus wurde isoliert, entfettet, zu konstantem Gewicht getrocknet und der Knochenaschengehalt und Kollagengehalt bestimmt. Acht der 10 experimentellen (immobilisierten) Humeri demonstrierte Beweis von verringerter Röntgendichte. Die immobilisierte Extremität zeigte ähnlichen Verlust in trockenem, fettfreiem Gewicht (−23,2%) in Kollagen (−25.3%) und Knochenasche (−26,1%) im Vergleich zur normalen Extremität. Die Date deuten an, daß der Hauptanteil des Verlustes des Knochengewebes (bei Immobilisations-Knochenatrophie) von Wasser, Fett und anderen unidentifizierten organischen Substanzen ersetzt wird, als von Faserngewebe und daß Kollagen und Knochenasche im gleichen Verhältnis verloren gehen. Der größere, proportionale Verlust an Kollagen und Knochenasche, eher als der Verlust an fettfreiem Gewicht, scheint in der Zunahme an nicht kollagener, nicht lipoider, organischer Substanz, vermutlich Protein, zu liegen.
    Notes: Abstract Disuse bone atrophy was induced in 10 adult dogs by means of brachial plexus section and/or elbow disarticulation. After 9 to 12 weeks of disuse intact humeri were examined by X-ray, and their physical properties determined. Thewhole humeri were isolated, defatted, dried to constant weight, and their mineral and collagen content determined. Eight out of 10 experimental (non-used) humeri demonstrated evidence of decreased radiodensity. The non-used limb demonstrated parallel loss in dry, fat-free weight (−23.2%), in collagen (−25.3%), and in mineral (−26.1%), as compared to the normal limb. The data indicated that the major portion of the lost bone tissue in disuse osteoporosis is replaced by water, fat, and other unidentified organic materials rather than fibrous tissue, and that collagen is lost in equal proportion to mineral. The proportionatelly greater loss of collagen and mineral than of dry, fat-free weight appears to be due to an increase of non-collagenous, non-lipid organic material, presumably protein.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 2 (1968), S. 214-228 
    ISSN: 1432-0827
    Keywords: Calcinosis ; Calcification ; Cartilage ; Collagen ; Mineral metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les facteurs, influençant la vitesse et l'intensité du phénomène d'association des ions calcium et phosphates avec des fibres contenant du collagène, et préparés à partir du tendon de boeuf par deux méthodes d'extraction différentes, ont été étudiés. Les fibres, obtenues par ces deux méthodes, nécessitent spécifiquement du phosphate pour absorber du calcium et vice versa. L'absorption ionique des deux préparations est inhibée par du Mg++, du pyrophosphate et un peptide acidique, isolé du sérum humain. Alors que les fibres contenant du collagène, préparées selon les deux méthodes, présentent une absorption ionique à des vitesses sensiblement identiques, seule une des méthodes donne une matrice réagissant positivement à la technique de coloration au nitrate d'argent de von Kossa. Etant donné que les deux critères de calcification sont intéressés de façon identique par des conditions de réaction et par des inhibiteurs, il apparait que les deux facteurs sont des manifestations de différents stades de calcification et que des études d'absorption ionique fournissent une base quantitative d'appréciation de la calcification, pouvant être d'importance pour l'étude du mécanisme et de contrôle de la minéralisation tissulaire.
    Abstract: Zusammenfassung Überprüft wurden die Faktoren, welche Geschwindigkeit und Ausmaß der Erscheinung beeinflussen, wobei Calcium- und Phosphationen sich mit den kollagenhaltigen, durch zwei verschiedene Extraktionsmethoden aus Rindersehnen gewonnenen Fasern eng zusammenbinden. Die mit beiden Methoden zubereiteten Fasern benötigen spezifisch Phosphat für die Calciumaufnahme und Calcium für die Phosphataufnahme. Die Ionenaufnahme beider Arten wird durch Mg++, Pyrophosphat und saure, aus dem menschlichen Serum isolierte Peptide gehemmt. Während die nach beiden Methoden präparierten kollagenhaltigen Fasern eine Ionenaufnahme von beinahe gleicher Geschwindigkeit verursachen, ergibt nur eine dieser Methoden eine Matrix, die mit der Silbernitratfärbung nach vonKossa positiv reagiert. Da beide Calcifikationskriterien gleicherweise durch Reaktionsbedingungen und Inhibitoren beeinflußt werden, wird daraus geschlossen, daß beide Erscheinungen verschiedener Stadien des Gesamtcalcifikationsprozesses sind. Untersuchungen über die Ionenaufnahme ergeben eine quantitative Angabe der Verkalkung, welche für die Erforschung des Mechanismus und der Kontrolle der Mineralisation der Gewebe wichtig sein könnte.
    Notes: Abstract Factors that influence the rate and extent of the phenomenon in which calcium and phosphate ions become firmly associated with collagen-containing fibers prepared from beef tendon by two different extraction methods have been investigated. The fibers produced by both methods specifically require phosphate for calcium uptake and calcium is required for phosphate uptake. Ion uptake by both types is inhibited by Mg++, pyrophosphate, and an acidic peptide isolated from human serum. Whereas the collagen-containing fibers prepared by both methods induce ion uptake at nearly identical rates, only one of the methods produced a matrix that gives a positive response to the silver nitrate staining technique of von Kossa. Since both criteria of calcification are similarly influenced by reaction conditions and inhibitors, it is concluded that both are manifestations of different stages of the overall calcification process and that studies of ion uptake provide a quantitative assessment of calcification which could be of importance for investigating the mechanism and control of tissue mineralization.
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