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  • 11
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary O-phosphoserine [Ser(P)], O-phosphothreonine [Thr(P)], and γ-carboxyglutamic acid (Gla) have been identified in native, calcified cementum and in non-collagenous proteins which can be extracted from the tissue in EDTA at neutral pH. The concentrations of Ser(P) and Thr(P) and the amino acid composition of the EDTA extractable proteins are more similar to those found in bone than in dentin or enamel. The concentration of Gla in cementum is lower than it is in bone and higher than it is in enamel, which contains essentially no Gla. Based on the contents of Gla in these mineralized tissues and the distribution of alkaline and acid phosphatases in these tissues, it is speculated that Gla may be part of these or other proenzymes rather than being involved directly and structurally with the deposition of the mineral phase.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 12 (1973), S. 247-258 
    ISSN: 1432-0827
    Keywords: Bone ; Collagenase ; Heparin ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La quantité de collagénase d'os de souris, obtenue dans un milieu de culture d'os, cultivéin vitro, est augmentée pas l'addition d'héparine à une concentration optimale d'environ 50 unités/ml de milieu de culture. Le sulfate de dextrane et le Treburon (un ester polysaccharide-sulfurique synthétique), qui sont voisins au point de vue chimique et structural à l'héparine, sont aussi efficaces que l'héparine pour augmenter la quantité de collagénase de l'os de souris, récupérée dans le milieu de culture. L'héparine, outre son action de stimulation de synthèse et/ou de libération de callogénase d'os de souris, augmente aussi l'activeté spicifique des préparations globales et purifiées de l'enzyme, dont l'activité est testée sur du collagène à l'état solide comme substrat. Aucune augmentation d'activité enzymatique n'est notée lorsque du collagène en solution est utilisé comme substrat. Le sulfate de dextrane est aussi effectif que l'héparine pour obtenir une augmentation de l'activité enzymatique, en utilisant le collagène solide comme substrat. Ni l'héparine ou le sulfate de dextrane augmente l'activité de la collagénase deClostridium histolyticum. Pour la première fois, une collagénase tissulaire purifiée dégrade et solubilise du collagène tissulaire non dénaturé et insoluble à 37° C. De plus, étant donné que cette action est nettement augmentée par l'addition d'héparine, il semble que cette dernière et des substances similaires peuvent jouer un rôle important dans la régulation de la dégradation collagénique pendant le remaniement des tissus collagéniquesin vivo.
    Abstract: Zusammenfassung Die Menge von Mäuseknochen-Kollagenase, die sich im Gewebezucht-Medium vonin vitro gezüchteten Knochen wiederfindet, konnte durch Zusatz von Heparinat in einer optimalen Konzentration von ungefähr 50 E/ml Medium erhöht werden. Dextransulfat und Treburon (ein synthetischer Polysaccharid-Sulfatester), welche strukturmäßig und chemisch dem Heparin nahestehen, wirkten sich auf die Erhöhung der im Gewebezucht-Medium zurückgewonnenen Mäuseknochen-Kollagenase im gleichen Maße aus wie Heparin. Nebst der stimulierenden Wirkung auf die Synthese und/oder die Freisetzung von Mäuseknochen-Kollagenase vermochte Heparin auch die spezifische Aktivität von ungereinigten und von gereinigten Enzympräparaten zu erhöhen, wenn für den Versuch Kollagen in fester Form als Substrat verwendet wurde. Mit gelöstem Kollagen als Substrat trat diese Wirkung dagegen nicht ein. Dextransulfat zeigte die gleiche Wirksamkeit wie Heparin, indem es die Enzymaktivität zu erhöhen vermochte, wenn Kollagen in fester Form als Substrat vorlag. Weder Heparin noch Dextransulfat erhöhten die Aktivität der Kollagenase ausClostridium histolyticum. Erstmals konnte gezeigt werden, daß eine gereinigte Gewebe-Kollagenase in der Lage ist, nicht-denaturiertes, unlösliches Gewebekollagen bei 37° sowohl abzubauen als auch aufzulösen. Da diese Wirkung durch Zusatz von Heparin noch deutlich erhöht werden konnte, läßt sich überdies vermuten, daß Heparin und heparinähnlichen Substanzen bei der Regulierung des Kollagen-Abbaues während der Umgestaltung von Kollagengewebein vivo eine wichtige Rolle zufällt.
    Notes: Abstract The amount of mouse bone collagenase recovered in the tissue culture medium of bone culturedin vitro was increased by the addition of heparin at an optimal concentration of approximately 50 units/ml of tissue culture medium. Dextran sulfate and Treburon (a synthetic polysaccharide-sulfuric ester) which are structurally and chemically related to heparin were as effective as heparin in increasing the amount of mouse bone collagenase recovered in the tissue culture medium. In addition to stimulating the synthesis and/or release of mouse bone collagenase, heparin was also found to increase the specific activity of both crude and purified preparations of the enzyme when assayed using collagen in the solid state as the substrate, but showed no enhancement of enzyme activity when assayed using collagen in solution as the substrate. Dextran sulfate was as effective as heparin in increasing the activity of the enzyme using collagen in the solid state as a substrate. Neither heparin or dextran sulfate enhanced the activity ofClostridium histolyticum collagenase. For the first time, a purified tissue collagenase has been shown to both degrade and solubilize undenatured, insoluble tissue collagen at 37°. Moreover, since this action was markedly enhanced by the addition of heparin, it suggests that heparin and similar substances may play an important role in the regulation of collagen degradation during the remodeling of collagenous tissuesin vivo.
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  • 13
    ISSN: 1432-0827
    Keywords: Bone ; Mineral ; Amorphous calcium phosphate ; X-ray diffraction ; Radial distribution function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary X-ray diffraction radial distribution function analysis was used to determine if a significant amount of an amorphous solid phase of calcium phosphate exists in bone, and if so, whether the amount varies as a function of age and maturation. Unfractionated cortical bone from embryonic and posthatch chicks of various ages and a low-density fraction of embryonic bone were studied. No evidence was found for the presence of an amorphous solid phase of calcium phosphate in any of the samples studied, including the recently deposited bone mineral of the low density fraction of embryonic bone. As little as 12.5% of synthetic amorphous calcium phosphate (ACP) added to bone was readily detected by the radial distribution function technique used. The results clearly indicate that the concept that ACP is the initial solid mineral phase deposited in bone, and the major mineral constituent of young bone is no longer tenable. The concept does not provide an accurate description of the nature of the initial bone mineral deposited, or the changes that occur with maturation, nor can it acount for the compositional and X-ray diffraction changes that the mineral component undergoes during maturation and aging.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A mutation of the ATF-2 gene was introduced into the germ line of mice (Fig. la-c) and confirmed by northern blotting, Southern blotting of reverse-transcribed polymerase chain reaction (RT-PCR) products (Fig. ld,e), western blotting of brain extract (Fig. I/), and mobility shift assay using ATF-2 ...
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-0827
    Keywords: Calcification ; Calciphylaxis ; Skin ; Serine Phosphate ; Threonine Phosphate ; γ-Carboxyglutamic Acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The amount of non-collagenous proteins is increased greatly during the pathological calcification of rat skin experimentally induced by dihydrotachysterol (DHT) and Ovalbumin (topical cutaneous calciphylaxis). This is accompanied by an increase in the total amount and concentrations of protein-bound serine phosphate [Ser(P)], threonine phosphate [Thr(P)] and γ-carboxyglutamic acid (Gla), almost all of which can be extracted from the tissue and can be dissociated from collagen in 0.5M EDTA. The EDTA-soluble, non-collagenous proteins are rich in aspartic and glutamic acids, similar to the non-collagenous, EDTA-soluble proteins of bone, cementum and calcified cartilage, and quite distinct from those of dentin and enamel.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Uncalcified samples of turkey tendon obtained prior to calcification, and other samples from areas of tendon that never calcify, contain little or no 0-phosphoserine [Ser(P)], 0-phosphothreonine [Thr(P)] and γ-carboxyglutamic acid (Gla). Significant amounts of all three of these Ca2+-binding amino acids, which are found in EDTA-extractable, non-collagenous proteins, are detected coincident with the onset of mineralization of a tendon and increase in concentration as mineralization proceeds.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 19 (1984), S. 723-736 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An investigation of the molecular structure of bone mineral and synthetic calcium phosphates was carried out using radial distribution function (RDF) techniques. The X-ray data were collected using CuKα and MoKα radiation to insure the validity of the RDFs. Synthetic preparations of hydroxyapatite (HA) varying in their crystal size and crystallinity, and amorphous calcium phosphate (ACP), were studied, as well as bone samples from a 1-year-old chicken and 16-day embryonic chicks. Mixtures of embryonic bone and synthetic ACP were also investigated. The RDFs of bone and crystalline HA samples are similar in peak position, and show evidence of an atomic order extending to 2.5 nm and beyond. The RDF of ACP differs from that of HA, showing only short range order up to 0.9 nm, as well as small differences in peak shape. The decrease in intensity of the RDF function with increasing distance (r), observed with both HA and bone samples can be related to a decrease in crystallinity and crystal size. The RDF data indicate there is no significant amount of ACP in either very young or mature bone. The RDFs of the embryonic bone + synthetic ACP mixtures showed that a small amount of ACP can be readily detected in a sample of bone with a poorly crystalline mineral phase; from this we estimate the threshold for detection of ACP in bone to be 12% or less.
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  • 18
    ISSN: 1058-8388
    Keywords: Embryonic development ; hXBP-1 ; Basic domain/leucine zipper protein ; Pancreas ; Salivary glands ; TIMP ; Alkaline phosphatase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The spatial and temporal distribution of transcripts for the TRE/CRE-binding basic region-leucine zipper protein hXBP-1 was determined by in situ hybridization. Analysis of embryos from day 10.5 to 18.5 pc revealed high level expression of hXBP-1 RNA in two developing organ systems: (1) in bone and cartilage cells of the developing skeleton and toothbuds, and (2) in exocrine glands including the pancreas and the submandibular and salivary glands. High level expression was also found in whisker follicles and in selected cells in brown adipose tissue. In the developing skeleton, hXBP-1 RNA was expressed starting on day 11.5 pc in osteoblasts of newly formed intramembranous bone. Thereafter, hXBP-1 was expressed in both osteoblasts and preosteoblasts in bone formed directly by intramembranous formation as well as in bone formed during endochondral ossification. The most intese signal was observed in preosteoblasts and osteoblasts of newly forming bone. At day 11.5 pc low level hXBP-1 expression was also observed in matrix secreting chondroblasts of bones which are formed initially of cartilage, at the stage where they consist entirely of cartilage, at the stage where they consist entirely of cartilage. Signal was also present in matrix producing chondroblasts of the mature zone of the growth region during endochondral ossification although at significantly lower level than in osteoblasts. hXBP-1 is thus the first transcription factor described, to our knowledge, whose level of expression is modulated during the osteoblast developmental sequence in vivo. The pattern of expression of hXBP-1 in the developing skeleton was found to be very similar to that of the genes encoding the tissue inhibitor of metalloproteinase and alkaline phosphatase throughout development. These observations suggest that hXBP-1 may play a role in regulating the expression of tissue specific genes (TIMP, osteonectin, osteopontin, osteocalcin) expressed in osteoblasts. It is intriguing that the promoter regions of several such genes contain potential hXBP-1 binding sites. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 224 (1989), S. 139-153 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Samples of decalcified chicken bone together with varying concentrations of phosphoproteins from bone or egg yolk (phosvitin) were used in vitro as heterogenous nucleators for the induction of Ca-P apatite crystals. The lag time between exposure of the collagen-phosphoprotein complexes and the time nucleation of crystals occurred decreased as the concentration of Ser(P) and Thr(P) increased. Enzymatic cleavage of the phosphate groups by wheat germ and phosphatase reversed this effort, indicating that the phosphate group per se principally facilitated the nucleation of Ca-P crystals by the phosphoprotein complex and collagen.
    Additional Material: 3 Ill.
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  • 20
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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