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  • Calcification
  • Enamel
  • Resorption
  • Springer  (70)
  • MDPI Publishing
  • 1980-1984  (42)
  • 1965-1969  (28)
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  • Springer  (70)
  • MDPI Publishing
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Year
  • 1
    Electronic Resource
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    Springer
    Calcified tissue international 36 (1984), S. 214-218 
    ISSN: 1432-0827
    Keywords: Proteolipid ; Calcium-phospholipid-phosphate complexes ; Calcification ; Hydroxyapatite ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This study demonstrates that calciumphospholipid-phosphate complexes (CPLX) and calcifiable proteolipid are associatedin vivo by establishing that they can be co-isolated from calcified bacteria. Both of these membrane constituents, which support apatite formationin vitro, have been isolated independently fromBacterionema matruchotii. However, isolation of proteolipid was preceded by demineralization in 2N formic acid, thereby dissociating bound Ca, whereas isolation of CPLX included sonication of calcified bacteria in 2:1:1.5 chloroform:methanol:Tris buffer, thereby dissociating any protein. Co-isolation is possible by demineralizing the calcified bacteria with 50 mM phthalic acid, pH 5.5, followed by extraction with 2:1 chloroform:methanol, and precipitation of crude phospholipid with acetone. CPLX and proteolipid are present in all Sephadex LH-20 chromatographic fractions of the crude phospholipid and of diethyl ether precipitates of the crude phospholipid. CPLXs contain protein:phospholipid:Ca:Pi but differ in relative composition from each other and from independently isolated CPLX. The Ca:phospholipid:Pi molar ratio of diethyl ether precipitable proteolipid-CPLX is most similar to previously published values for CPLX. The protein content of CPLX accounts for all of the proteolipid apoprotein in each Sephadex LH-20 fraction.
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  • 2
    ISSN: 1432-0827
    Keywords: Phosphoprotein ; Dentin ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Free and matrix-bound phosphophoryns, both highly phosphorylated proteins in dentin, were prepared from EDTA extract and CNBr-digests of bovine dentin. The two components were purified by DEAE-cellulose, SP-Sephadex, and gel filtration chromatography. The matrix-bound component was eluted as a distinct peak from the free component in the above chromatographic systems. Amino acid composition of the purified matrixbound component indicated that this component consisted of phosphophoryn and collagen in the ratio of 2:3 based on the number of the residues. The matrix-bound component could not be reconstituted by mixing phosphophoryn with collagen CNBr peptides. Artificial crosslink products of free phosphophoryn and collagen CNBr-peptides by the carbodiimide method showed similar properties to the physiological matrix-bound phosphophoryn. The bond between phosphophoryn and collagen of the matrix-bound component is assumed to be a covalent crosslink.
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  • 3
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    Calcified tissue international 36 (1984), S. 39-47 
    ISSN: 1432-0827
    Keywords: Apatite ; Calcium phosphates ; Crystal growth ; Enamel ; Octacalcium phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present study examined crystal growth on enamel and synthetic apatite seed surfaces in dilute supersaturated solutions by means of transmission electron microscopy. At all supersaturations, new growth initially appeared on the ends of the seed crystal. In solutions undersaturated with respect to octacalcium phosphate (OCP), this growth was needlelike in appearance. Above the solubility point for OCP, the growth frequently took the form of thin, platelike crystals. The relevance of these findings to precursor phase formation is discussed.
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  • 4
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    Calcified tissue international 36 (1984), S. 64-71 
    ISSN: 1432-0827
    Keywords: Solubility of calcium salts ; Enamel ; Hydroxyapatite ; Carbohydrates ; Complex formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The solubility of various Ca(II) salts, hydroxyapatite, and powdered human dental enamel in the presence of simple carbohydrates was studied by determining the complex strength between Ca(II) and the carbohydrates. In 1.0m CaSO4, the following simplified sequence of complex strengths was obtained for the more common carbohydrates: Na-citrate〉d-sorbitol〉xylitol〉d-mannitol〉d-fructose〉d-glucose〉d-xylose. Whereas the more soluble Ca(II) compounds (like CaSO4) exerted measurable complexation with xylitol, no such complexation was found with hydroxyapatite and enamel powder. This also concerned other alditols. Calculation of the stability constants (K) showed sorbitol (K=0.81 M) and xylitol (K=0.67m) to form stronger complexes in saturated CaSO4 than other alditols. The most suitable coordination site appeared to be a vicinalcis-cis-triol. Precipitation studies showed that 0.5m xylitol and 0.5 M sorbitol significantly retarded the formation of calcium phosphate precipitates from a solution of Ca(II) and phosphate, compared with the effect caused by glucose, sorbose, or xylose. The effect caused by xylitol and sorbitol was explained in terms of partial displacement of water molecules in the primary hydration layer of Ca(II) ions, caused by competition between polyol and water molecules. In the presence of aldoses and ketoses, virtually instantaneous precipitation occurred. These results suggest that open-chain alditols may influence the chemical reactions of Ca(II) in plaque, saliva, and caries lesions. Alditols do not function as demineralizing agents of the teeth, however. Through the retarding effect on calcium phosphate precipitation, alditols may favorably govern remineralization of carious lesions.
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  • 5
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    Calcified tissue international 36 (1984), S. 332-337 
    ISSN: 1432-0827
    Keywords: Proteolipid ; Phospholipids ; Vitamin D ; Calcification ; Cartilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Previous studies have shown thatin vitro calcification of chick epiphyseal cartilage matrix vesicles is proteolipid-dependent. The purpose of this research is to examine the role of proteolipid in cartilage calcificationin vivo by comparing the proteolipid concentration of normal and vitamin D-deficient chick epiphyseal cartilage, the relationship of proteolipid to other tissue lipids, and its ability to supportin vitro apatite formation. Proteolipid was isolated from the upper growth centers (reserve cell zone, upper proliferative zone) and lower growth centers (lower proliferative, hypertrophic, and calcified cartilage zones) of long-bone epiphyses from 3-week-old normal and rachitic male white leghorn chicks by Sephadex LH-20 chromatography of the crude phospholipid component of the total lipid extract. In both normal and rachitic tissue the proteolipid/dry weight and proteolipid/total lipid ratios were greater in the lower growth center than in the upper zones. No statistically significant change in the proteolipid/total lipid ratio in rachitic tissues relative to comparable cell zones in normal cartilages was observed. However, there was an increase in the nonproteolipid phospholipid content of rachitic tissues, altering the relative proteolipid/phospholipid composition. Whereas proteolipids from normal tissue supportedin vitro calcification, proteolipids from rachitic tissues did not, indicating a direct effect of vitamin D on proteolipid structure. These data support the hypothesis that failure of rachitic cartilage to calcifyin vivo may be due in part to alterations in phospholipid and proteolipid metabolism.
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  • 6
    ISSN: 1432-0827
    Keywords: Mineralizing tissue ; Enamel ; Density fractionation ; Apatite ; Amelogenins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An aqueous density fractionation for calcifying tissues was tested for its ability to prepare fractions corresponding to precise mineralization stages, suitable for further protein and crystal studies. Two fractions of immature enamel corresponding to different densities were prepared, using cooled cesium salt saturated solutions, and compared for crystal size and amelogenin molecular weight distribution. For the first time, a steep increase in crystal width was directly correlated to protein degradation in keeping with increasing mineralization. Thus, this paper describes a method for obtaining an accurate fractionation of a calcifying tissue according to its true density heterogeneity. The recovered fractions are shown to be suitable for both crystal and protein studies.
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  • 7
    ISSN: 1432-0878
    Keywords: Gorgonians ; Organic matrix ; Autoradiography ; Calcification ; Leptogorgia virgulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sequence of the synthesis and transport of the organic matrix of spicules has been elucidated in the gorgonian Leptogorgia virgulata by use of 3H-aspartic acid as the tracer in electron-microscopic autoradiography. The entire process of matrix synthesis and transport takes approximately 2 h. It seems that the protein moiety of the organic matrix is synthesized in the RER prior to 5 min following the initial 10 min incubation in the tracer. At the 5 min chase the label is moving from the RER to the Golgi complexes where the carbohydrate moiety of the matrix is presumed to be synthesized. At the 5 to 15 min chases the label is transported out of the Golgi complexes via Golgi vesicles. This phase continues for 30 min. From 60 to 120 min the 3H-aspartic acid moves to the spicules. After 120 min the majority of the label has moved into the spicules. Silver grain counts over both multivesicular and electron-dense bodies remain at relatively low and constant levels over 4 h indicating that neither organelle is involved in the synthesis and transport of the organic matrix.
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  • 8
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    Cell & tissue research 236 (1984), S. 413-420 
    ISSN: 1432-0878
    Keywords: Calcification ; Crab cuticle ; Cell coat glycoprotein ; Carbonic anhydrase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the crab cuticle the interprismatic septa (IS), which correspond to imprints left in the cuticle by the margins of the epidermal cells, penetrate the twisted structure of the chitin-protein matrix. The ultrastructure and geometric relationship between the fibrous architecture and the pattern of the prisms is described. The cytochemical characterization of the IS, by pronase treatment and ruthenium red staining, supports the hypothesis that this material corresponds to cell-coat glycoproteins released in the cuticle during secretion of the organic matrix. Calcification begins after ecdysis in the external laminae of the pigmented layer and along the IS. The presence of cation-binding glycoproteins in the sites where calcification is initiated could induce the nucleation of the mineral phase by concentrating calcium. The extracellular distribution of carbonic anhydrase, which favours carbonate deposition, is observed on ultrathin sections over the IS.
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  • 9
    ISSN: 1432-0827
    Keywords: Calcification ; Glycosaminoglycan ; Glycoprotein ; Collagen ; Acid phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Glycosaminoglycans (GAGs) and glycoproteins are essential components for osteogenesis. We have examined rat osteoblasts, osteoid, transitional zone, and fully calcified bone matrix, utilizing Spicer's high-iron diaminethiocarbohydrazide-silver protein (HID-TCH-SP) method for sulfated glycoconjugates and Thiéry's periodate-TCH-SP (PA-TCH-SP) method for vicinal glycol-containing glycoconjugates. HID-TCH-SP stained cytoplasmic granules of osteoblasts. Stain deposits in the extracellular matrix were observed in decreasing amounts in osteoid, the transitional zone, and fully calcified bone matrix. Enzyme digestion with testicular hyaluronidase removed most HID-TCH-SP stain deposits. PA-TCH-SP staining was observed with increasing intensity in rough endoplasmic reticulum, Golgi saccules, and cytoplasmic granules. Collagen fibrils in osteoid were weakly stained with PA-TCH-SP, and their staining appeared even weaker in fully calcified bone matrix. In contrast, collagen fibrils in calcified cartilage stained intensely with the PA-TCH-SP method. Focal circular profiles (0.1–0.5µm in diameter), which lacked collagen fibrils but reacted moderately with PA-TCH-SP, were frequently seen in the transitional zone and fully calcified bone matrix, but were only occasionally present in osteoid. The presence of testicular hyaluronidase-resistant GAG and acid phosphatase in these focal areas suggests that they represent sites of GAG degradation. The eventual loss of HID-TCH-SP staining in the bone matrix suggests that removal of sulfated glycoconjugates may be a requisite for expansion of initial calcification sites and/or complete calcification.
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  • 10
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    Calcified tissue international 35 (1983), S. 48-55 
    ISSN: 1432-0827
    Keywords: Enamel ; Density centrifugation ; Hydroxyapatite ; Carbonate ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Whole enamel scrapings from unerupted teeth of embryonic calves have been separated into fractions of varying density by stepwise centrifugation in bromoform-toluene mixtures of increasing specific gravity. Partition of enamel in this manner yields individual fractions of increasing mineral phase age and maturation. Whole scrapings and isolated fractions of the fetal bovine enamel were examined by X-ray powder diffraction, scanning electron microscopy, and atomic absorption and infrared spectroscopy to determine time-related changes in the physicochemical nature of the constituent mineral phase particles. These analyses showed poorly crystalline hydroxyapatite (HA) as the only detectable solid phase of calcium phosphate present in all fractions, its degree of crystallinity increasing with increasing density. Molar Ca/P ratios and magnesium content were highest in lowest density fractions. Carbonate vibration bands at 875 and 1420–1450 cm−1, common to mineralized tissue, were observed in intermediate and higher density fractions and in whole unfractionated enamel. Another carbonate band at ∼705 cm−1, unusual to vertebrate calcified tissue, was detected in low density fractions and disappeared rapidly with increasing enamel maturation. Its precise relation with the enamel mineral phase has not been determined.
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  • 11
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; 32P-phosphate and45Ca-metabolism ; Epiphyseal cartilage ; Calcification ; Alkaline phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Matrix vesicle-enriched fractions were isolated from different zones of epiphyseal cartilage by nonenzymatic methods involving tissue homogenization, differential centrifugation, and isosmotic Percoll gradient fractionation. Uptakes of both32Pi and45Ca were studied concomitantly over periods from 20 min to 24 h. Percoll density gradients separated epiphyseal microsomes into two alkaline phosphatase-rich fractions: a low-density noncalcifiable fraction (P-I), and a higher-density fraction (P-II) which readily mineralized. The P-II fraction was found only in calcifying regions of the growth plate. Based on chemical and physical properties and enzyme activities, both fractions were similar except that P-II contained significantly higher levels of mineral ions than did P-I, and had lower levels of alkaline phosphatase. The mineral appeared to be primarily in a noncrystalline form. Metabolism of32Pi and45Ca by P-II followed a complex kinetic pattern in which accumulation of large amounts of both ions was preceded by an initial limited burst of uptake and a lag-phase of variable duration. During mineral ion loading, the density of the P-II fraction progressively increased as evidenced by co-migration of45Ca,32Pi, and alkaline phosphatase to increasingly higher densities. During the period of early mineral deposition (1–5 h), Ca/P uptake ratios were very low (1.0–1.2) and X-ray diffraction patterns showed a predominantly amorphous pattern. This suggests that the mineral accumulated in matrix vesicles is initially some form of noncrystalline calcium monohydrogenphosphate. L-tetramisole, a potent inhibitor of alkaline phosphatase, inhibited accumulation of both45Ca and32Piin the absence of organic P substrates,32Pi being preferentially inhibited over45Ca. This finding, coupled with recent studies on the behavior of alkaline phosphatase at physiological pH, suggests that the protein is not acting as a phosphohydrolase, but rather as a Pi-binding or transport agent in vesicle-mediated calcification.
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  • 12
    ISSN: 1432-0827
    Keywords: ADP ; Bisphosphonate ; Bone ; Resorption ; Formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of 1.5–2 years oral administration of disodium (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate (APD) on bone metabolism were studied in male and female rats. APD was mixed in the food at levels of 500, 2,000 and 10,000 ppm. A dose-dependent increase in metaphyseal bone was found, indicative of continued inhibition of bone and cartilage resorption. APD did not affect mineralization of bone and cartilage, primary bone formation, or periosteal apposition. A short-term metabolic balance study was performed to compare the effects of oral with subcutaneous APD. Absorption of APD was in the order of 0.2%. Oral APD increased absorption of phosphate, probably by complexation of calcium with APD. The excess absorbed phosphate increased phosphaturia and decreased urinary calcium.
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  • 13
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    Calcified tissue international 35 (1983), S. 723-727 
    ISSN: 1432-0827
    Keywords: Calcification ; Scleroderma ; CRST syndrome ; High resolution TEM ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This paper reports the study of a subcutaneous heterotopic calcification from a patient with Thibierge-Weissenbach's syndrome, a type of creeping scleroderma included in the CRST syndrome. These local deposits, whose origin is still unknown, are commonly considered to be a classic apatite phase. Using SEM, high resolution TEM, electron diffraction, infrared spectrometry, and SEM and TEM microanalysis, it is demonstrated that this material is highly heterogeneous and appears in a nonstoichiometric, carbonated, calcium ion-deficient apatitic solid phase. Our study shows the co-existence of dense globules presenting an ill-organized, more or less amorphous phase (ACP) or microcrystalline (OCP, β tricalcium phosphate), with scattered apatite crystals, and of interglobular apatite crystals with a good cristallinity.
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  • 14
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    Calcified tissue international 35 (1983), S. 783-790 
    ISSN: 1432-0827
    Keywords: Amorphous calcium phosphate ; Apatite ; Calcification ; Hydrolysis ; Octacalcium phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The hydrolysis of previously prepared amorphous calcium phosphate (ACP) was studied in a solution “saturated” with ACP; this eliminated the initial consumption of acid due to ACP dissolution. The procedure established that conversion of a high-concentration ACP slurry to an apatite involves two processes: the first process consumes acid and indicates the formation of a more acidic calcium phosphate intermediary with the solubility of octacalcium phosphate (OCP); the second process consumes base and indicates the conversion of the intermediary to apatite and, possibly, direct conversion of ACP to apatite. The thermodynamic analysis of the solution composition data suggests that ACP converts into a nonstoichiometric apatite when the OCP-like intermediary is formed, and a stoichiometric apatite is formed when no OCP-like intermediary is involved.
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  • 15
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    Calcified tissue international 35 (1983), S. 304-308 
    ISSN: 1432-0827
    Keywords: Immobilization ; Bone strength ; Resorption ; Recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We studied the mechanical properties and structural changes in the monkey tibia with disuse osteoporosis and during subsequent recovery. Bone bending stiffness was evaluated in relationship to microscopic changes in cortical bone and Norland bone mineral analysis. Restraint in the semireclined position produced regional losses of bone most obviously in the anterior-proximal tibiae. Following 6 months of restraint, the greatest losses of bone mineral in the proximal tibiae ranged from 23% to 31%; the largest changes in bone stiffness ranged from 36% to 40%. Approximately 8 ½ months of recovery were required for restoration of normal bending properties. However, even after 15 months of recovery, bone mineral content did not necessarily return to normal levels. Histologically, resorption cavities in cortical bone were seen within 1 month of restraint; by 2 ½ months of restraint there were large resorption cavities subperiosteally, endosteally, and intracortically. After 15 months of recovery, the cortex consisted mainly of first-generation haversian systems. After 40 months, the cortex appeared normal with numerous secondary and tertiary generations of haversian systems.
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  • 16
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    Calcified tissue international 35 (1983), S. 762-766 
    ISSN: 1432-0827
    Keywords: Enamel ; Maturation cycles ; Tetracycline ; Dentine ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Uptake of tetracycline by enamel in the short-term was studied at an advanced stage of crown formation and after completion of crown formation in deciduous molars in the cat. Both secretory phase enamel and bands of postsecretory, maturation phase enamel labeled rapidly. The pattern of labeling mimicked that seen in the continuously growing, rootless incisor teeth of the rat, with narrow doublets fusing to form narrow bands with wide unlabeled intervals in the short term. This is a physiological demonstration which indicates that cyclical activity and changes may occurin vivo during the maturation phase of amelogenesis in rooted teeth. It is also noted that dentine did not, and that some circumscribed patches of bone did label in the same animals in the same time interval. Short-term tetracycline labels are lost following conventional histological processing, but are retained after freeze-drying or air-drying.
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  • 17
    ISSN: 1615-6102
    Keywords: Calcification ; Coccolithophorids ; Polysaccharide localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Emiliania huxleyi is a marine coccolithophorid which produces coccoliths,i.e., particles consisting of calcite and macromolecular organic material. The coccoliths are formed intracellulary in specialized organelles which comprise a coccolith vesicle (CV) and a reticular body (RB), together forming the CV/RB system or calcifying system. After termination of calcification, the coccolith is extruded and incorporated into the coccosphere,i.e., one or several layers of extracellular coccoliths surrounding the cell. Apart from the coccolith-producing cells (C cells) ofE. huxleyi, there are naked cells (N cells) which seem to have lost the capacity to produce coccoliths but are very similar to the C cells in other morphological respects. Biochemical studies have revealed that polysaccharides may play a regulatory role in calcification. The aim of the present study was to determine the localization of polysaccharides in both C and N cells electron microscopically. For this purpose, a cytochemical staining technique according toThiéry (1967) was applied. The CV/RB system of C cells was conspicuously stained. Due to the excellent stainability of this system, a putative succession of morphological stages during coccolithogenesis could be described. The staining pattern of the N cells closely resembled that of the C cells. It was found, however, that the “calcifying” system of N and C cells differed in both morphology and position. It is suggested that the divergent morphology of the “calcifying” system of N cells accounts for its failure to produce coccoliths.
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  • 18
    ISSN: 1432-0827
    Keywords: Hamster amelogenins-enamelins ; Enamel ; Dentin-phosphoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Amelogenins, enamelins, and soluble dentin proteins were sequentially separated under dissociative conditions from morphologically characterized molar tooth germs of 4-, 6-, and 7-day-old hamsters. Polyacrylamide gel electrophoretic, gel filtration chromatographic, and amino acid compositional data of neonatal hamster amelogenin extracts were in general agreement with those obtained from fetal bovine enamel under similar extraction conditions. As development progressed (e.g., 4 vs. 7 days of life), changes in amelogenin proteins were manifested by altered values of all biochemical parameters measured. A high molecular weight (∼160,000–200,000 daltons) Stains-All-positive protein band was observed for all hamster enamelin extracts on SDS gels. Amino acid compositional data from this “enamel crystal protein,” partially purified by dissociative gel-filtration chromatography, are presented. The hamster dentin phosphoprotein was partially purified by ion-exchange chromatography in 7M urea. The molecular weight (75,000–80,000 daltons) and amino acid composition of this protein were similar to those of rat incisor dentin phosphoprotein, but different from those of the fetal bovine phosphoprotein.
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  • 19
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    Calcified tissue international 34 (1982), S. 209-210 
    ISSN: 1432-0827
    Keywords: Enamel ; crystallographic fault ; caries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary There is a range of experimental evidence consistent with the existence of planar defects in the apatite crystals which constitute dental enamel. The evidence includes the appearance of crystals in the electron microscope both before and after attack by caries or caries-simulating etchants, the cross-sectional shape of the crystals and their long lath-like morphology. It is suggested here that the defects are twin planes in the apatite structure and it is further shown that such twin faults can form with only minor disturbance to the structure.
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  • 20
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    Calcified tissue international 34 (1982), S. 428-430 
    ISSN: 1432-0827
    Keywords: Epiphyseal cartilage ; Carbonic anhydrase ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The distribution of carbonic anhydrase isoenzymes C and B in the rat epiphyseal growth cartilage was demonstrated by an immunohistochemical method. The isoenzymes were found in different locations. Isoenzyme C was in the extracellular matrix of the hypertrophic and calcifying cartilage, and no reaction was observed in the chondrocytes. In contrast, the antiserum against isoenzyme B revealed only a weak cellular staining. This supports the hypothesis that carbonic anhydrase isoenzyme C, which is the high-activity form, changes the pH in the extracellular fluid of calcifying cartilage, favoring the deposition of calcium phosphate.
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  • 21
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    Calcified tissue international 34 (1982), S. 382-390 
    ISSN: 1432-0827
    Keywords: Avian osteopetrosis ; Avian oncornavirus ; Ultrastructure ; Calcification ; Bone cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Diaphyseal tibial bone of 12.5 – 13-day and 19-day-old embryos and 20-day-old hatched chicks infected with retrovirus MAV.2-O were examined by transmission electron microscopy. The viruses were associated with lining osteoblasts and osteocytes. Whereas the infection of the osteoblast layer seemed to be a transient stage, virus association with osteocytes was a constant and main ultrastructural feature. The viruses were found either in the osteoid or in the periosteocytic space of the bone lacunae. They arose from dense cytoplasmic areas located near the cell plasmalemma via a budding process. The newly budded virus particles often had a large tail or a fine stalk-like process lost in the extracellular space. The viruses underwent calcification by deposition of inorganic material and were incorporated in the bone trabeculae. No production of virus was observed in typical osteoclasts with well-differentiated ruffled borders. The viral-induced avian osteopetrosis seemed to result from increased bone deposition through stimulation of osteoblast and osteocyte activities, whereas osteoclastic bone resorption seemed to be undisturbed.
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  • 22
    ISSN: 1432-0827
    Keywords: Bacterial amphophile ; Purification ; Chemistry ; Resorption ; Ca influx ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The bone resorptive factor and amphipathic antigen (AcA) previously identified by us in preparations fromActinomyces viscosus have been partially purified, characterized chemically, and compared. They elute at the same location on chromatography with Ac 22. The fatty acid composition of AcA and the bone resorptive factor is the same. Some differences in carbohydrate composition are observed. TheActinomyces factor does not affect calcium influx or cyclic AMP in isolated bone cells. Therefore it is concluded that AcA stimulates resorption either by gaining entrance into bone cells or by way of a yet undetermined second messenger.
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  • 23
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    European journal of nutrition 21 (1982), S. 202-213 
    ISSN: 1436-6215
    Keywords: Johannisbrotkernmehl ; Resorption ; Mineralstoffe ; Spurenelemente ; Bilanzversuch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The effect of carob bean gum (9.5 g/1000 kcal, 4184 kJ) in the daily diet on the absorption of Ca, Fe, Zn und Cu was determined during a 4-week balance study in 2 male and 6 female healthy subjects, aged 19 to 25 years. A normal mixed diet was used, to which carob bean gum was added during food preparation for the last 2 weeks of the study. The absorption of minerals and trace elements was calculated as the difference between dietary intake and fecal excretion. The ingestion of carob bean gum caused a significant reduction in the absorption of Ca, Fe and Zn when compared to the control diet, while the absorption of Cu remained unchanged.
    Notes: Zusammenfassung In einem vierwöchigen Bilanzversuch wurde der Einflu\ von Johannisbrotkernmehl (JBM) in der Nahrung (9,5 g/1000 kcal, 4184 kJ) auf die Resorption von Ca, Fe, Zn und Cu in zwei männlichen und sechs weiblichen gesunden Versuchspersonen im Alter zwischen 19 und 25 Jahren geprüft. Die Versuchsdiät bestand aus einer normalen Mischkost, der während der letzten zwei Wochen der Untersuchung JBM bei der Speisezubereitung zugefügt wurde. Die Resorption der Mineralstoffe und Spurenelemente wurde als Differenz aus Zufuhr mit der Diät und Ausscheidung im Kot berechnet. Die Zufuhr von JBM führte gegenüber der Kontrolldiät zu einer signifikanten Verringerung der Resorption von Ca, Fe und Zn. Die Cu-Resorption blieb unverändert.
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  • 24
    ISSN: 1432-0878
    Keywords: Gorgonians ; Spicule ; Scleroblast ; Calcification ; Leptogorgia virgulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural examination of original and regenerated branch tips of the gorgonianLeptogorgia virgulata reveals that spicule formation begins with the aggregation of scleroblasts in the mesoglea. Calcite crystal deposition occurs within a Golgi vacuole containing organic matrix. Vacuole size increases while matrix incorporation and subsequent crystal growth continue, filling the vacuole. At approximately this time, the scleroblasts dissociate and “wart” formation begins. Further spicule growth stretches the cell into a thin envelope. Fusion of vacuole and plasma membrane followed by breach formation during spicule growth, as well as scleroblast atrophy or migration from mature spicules, result in the transition of the spicule from the intracellular to the extracellular environment. The results also reveal aborted spicules and digestive bodies, implying possible relationships among calcification, detoxification, and waste management.
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  • 25
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    Calcified tissue international 33 (1981), S. 35-39 
    ISSN: 1432-0827
    Keywords: Copper ; Resorption ; Bone
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    Topics: Biology , Medicine , Physics
    Notes: Summary An investigation of the role of copper in bone metabolism was undertaken. Explanted calvaria from 6-day-old mice were grown for 48 h in medium with and without the addition of copper sulfate. Active resorption was found to be significantly inhibited in the presence of copper sulfate concentrations of 10−6M and above. Copper sulfate concentrations of 10−5M and above inhibited hydroxyproline, protein, and DNA synthesis. Lower concentrations were ineffective. The effect of 5 × 10−6M copper sulfate on resorption was reversible. Several other compounds were tested for similar effects and at 5 × 10−6M were found to inhibit bone resorption in the order: copper sulfate 〉 brown gold chloride 〉 sodium aurothiomalate 〉 zinc sulfate 〉 sodium sulfate. The copper sulfate effect was twice that of sodium aurothiomalate, and sodium sulfate was not significantly inhibitory. The results suggest that the high serum copper levels associated with rheumatoid arthritis may reflect the activity of a hypothetical control mechanism of bone resorption. In the diseased state this would act to restore the normal rate of bone resorption.
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  • 26
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    Calcified tissue international 33 (1981), S. 105-109 
    ISSN: 1432-0827
    Keywords: ESR ; Free radicals ; Apatite ; Enamel ; Irradiation
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    Topics: Biology , Medicine , Physics
    Notes: Summary Using both low microwave power and weak magnetic field modulation, we have shown that the asymmetric signal arising in X-irradiated tooth enamel as well as in A-type carbonated apatite exposed to X-rays or to excited oxygen has an orthorhombic character and must be attributed to CO 2 − . Effectively, the mean values found for the three g-tensor components are comparable to those quoted for this defect in single-crystal specimens of calcite and sodium formate.
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  • 27
    ISSN: 1432-0827
    Keywords: Fluoride ; Enamel ; Enameloid ; TEM ; Electron diffraction
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    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of fluoride on human enamel and selachian enameloid in vitro were visualized in TEM and analyzed with electron diffraction. It is demonstrated that under precise pH conditions, inducing concentration balance between F− ions and apatite, calcium fluoride is no longer formed, and crystalline changes occur instead. A secondary growing process, inducing a twofold increase in crystal size, involves all crystal faces, altering the hexagonal symmetry. It is suggested that the mechanism involved is not a dissolution/precipitation process but rather a secondary growth of residual crystallites induced by apatite dissolution.
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  • 28
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    Calcified tissue international 33 (1981), S. 603-618 
    ISSN: 1432-0827
    Keywords: Preameloblasts ; Tooth germs ; Monkey ; Enamel ; Ultrastructure
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    Topics: Biology , Medicine , Physics
    Notes: Summary Cytodifferentiation of inner enamel epithelium and the adjacent connective tissue from the tip of the cervical loop to the initiation of enamel elaboration in twoMacaca species was examined. Ten- to twelve-month-old specimens were fixed by perfusion and the permanent tooth buds were prepared for transmission electron microscopy. At the cervical loop proper, inner enamel epithelium cells have lobed nuclei, a paucity of cytoplasm, and wide extracellular spaces; the basal lamina facing the dental papilla is straight. With increasing distance from the tip of the cervical loop, the following changes occur gradually: (a) preameloblasts elongate from 15 to 45 µm, and their organelles, particularly mitochondria and profiles of rough endoplasmic reticulum, become more numerous; (b) extracellular spaces decrease between preameloblasts starting at the basal (infranuclear) end; (c) the basement membrane becomes convoluted and associated with aperiodic fibers; (d) preodontoblast projections penetrate the aperiodic fibers; (e) collagen fibers subjacent to the basement membrane increase in density, with particularly thick fibers paralleling the aperiodic fibers. These modifications occur within three-fourths of the distance from the tip of the cervical loop to the mineralization front. The condensation of preodontoblasts is followed immediately by predentin synthesis. Concomitantly, the basement membrane breaks down and the aperiodic fibers are engulfed by preameloblasts. Preameloblast projections penetrate junctional predentin, contact mineralized dentin, and enamel synthesis ensues. At this stage the ameloblast is 45 µm long, the nucleus is central or basal, the Golgi apparatus has migrated apically, but the Tomes' process has not yet formed. The results indicate that odontogenesis inMacaca monkeys more closely resembles human odontogenesis than does that in the murine rodents.
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  • 29
    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.
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  • 30
    ISSN: 1432-0878
    Keywords: Teeth (Marsupials) ; Enamel ; Dentine ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary Transmission electron microscopy of selected-area argon-ion-beam thinned kangaroo (Macropus giganteus) enamel revealed a complex ultrastructure in the region of the dentine-enamel junction (DEJ). Characteristic features were multiple branching of dentinal tubules, rejoining of enamel tubules, elongated defects, extended protrusions of dentine into enamel, two types (A and B) of hypomineralized enamel and a continuity between dentinal and enamel tubules. In the intertubular regions of the DEJ a complex intermingling of finer enamel and dentine crystals, similar to that found in human enamel, was observed. The varicosities observed in the light microscope were a combined optical effect caused by the hypomineralized (type A) enamel and the branching and rejoining of the enamel tubules.
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  • 31
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    Cell & tissue research 221 (1981), S. 421-430 
    ISSN: 1432-0878
    Keywords: Fluoride ; Bone ; Mineralization ; Resorption ; Rat
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    Topics: Biology , Medicine
    Notes: Summary The femurs from rats given 120 ppm fluoride in their drinking water for 4 weeks were examined with histological, histochemical, and radiographic methods. Blood removed from the rats prior to sacrifice was analyzed for calcium, phosphorus, and alkaline phosphatase. Results of this study indicated that the ingestion of fluoride produced wide osteoid seams on the periosteal surface of the femoral diaphysis within 4 weeks. The increase in osteoid appeared to be due to an increase in the number of osteoid-producing cells (osteoblasts) along with a subsequent delay in the mineralization of this tissue. The metabolic activity of osteoblasts did not appear to be affected since the intracellular production of acid and alkaline phosphatase was not inhibited. However, due to the high concentration of fluoride ingested, abnormal collagen deposition and a change in bone mineral may have combined to cause a delay in osteoid mineralization. Mineralization was also delayed in the distal femoral epiphyseal plate resulting in an increase in the number of hypertrophied cells. Resorption of metaphyseal trabecular bone, presumably formed prior to fluoride administration, was increased causing a reduction in the amount of trabeculae extending into the shaft of the femur. Concurrent with these changes in bone, the serum levels of calcium, phosphorus, and alkaline phosphatase remained within normal ranges.
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  • 32
    ISSN: 1432-0878
    Keywords: Matrix vesicles ; Calcification ; Articular cartilage ; Synovialgraft ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Free autologous grafts of synovial tissue were transplanted into experimental defects produced in the articular cartilage of rabbit knee joints. The grafted tissue underwent transformation into fibrocartilage. Extracellular matrix vesicles associated with calcified areas were present at the grafted sites. Hydroxyapatite crystals were found within these vesicles and in their vicinity. No calcification occurred in articular cartilage from sham operated joints in which defects were produced but no grafts made and in normal controls. These tissues showed abundant matrix vesicles devoid of crystalline mineral. A careful study of normal synovial tissue did not reveal matrix vesicles and calcifications. The present observations suggest that matrix vesicles in normal articular cartilage exist in a latent form. Vesicle mineralization following surgical manipulations of the joint is probably a manifestation of the metabolic stage of the tissue.
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  • 33
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    Calcified tissue international 30 (1980), S. 167-174 
    ISSN: 1432-0827
    Keywords: Proteolipid ; Calcium-phospholipid-phosphate complexes ; Calcification ; Hydroxyapatite ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calcium-phospholipid-phosphate complexes (Ca-PL-P) were isolated from calcified and uncalcifiedBacterionema matruchotii and its calcified lipid extracts. Similar complexes were absent from the noncalcifying bacteriumActinomyces naeslundii. The majority of the Ca-PL-P complexes were associated with the proteolipid acidic phospholipid component. Ca-PL-P complexes isolated fromB. matruchotii and from calcified proteolipid contained phosphatidylinositol, phosphatidylinositol-4-phosphate, phosphatidylinositol-4,5-diphosphate, and phosphatidylserine. They consisted of approximately 52 mole % Ca, 32 mole % organic P, and 15 mole % Pi. During Ca-PL-P extraction fromB. matruchotii or its proteolipid-containing calcified lipid extracts, the proteolipid was dissociated and the apoprotein precipitated as fluff at the aqueous-organic solvent interface, thus explaining the failure to detect protein in Ca-PL-P preparations. When the ability of Ca-PL-P complexes and lipid fractions ofB. matruchotii to initiate apatite formation from metastable calcium phosphate solution was compared, the yield of hydroxyapatite decreased as follows: Ca-PL-P 〉 proteolipid acidic phospholipids 〉 proteolipid 〉 crude phospholipid 〉 total lipids 〉 whole cells.
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  • 34
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    Calcified tissue international 32 (1980), S. 139-143 
    ISSN: 1432-0827
    Keywords: Calcification ; Magnesium ; Phospholipids ; Ca-phospholipid-phosphate complex ; hydroxyapatite
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    Topics: Biology , Medicine , Physics
    Notes: Summary The effect of Mg on hydroxyapatite proliferation induced by phosphatidyl serine, phosphatidyl inositol, and calcium-acidic phospholipidphosphate complexes has been studied in metastable calcium phosphate solutions of constant ionic strength and variable Mg/Ca ratio. Mg inhibits formation of the Ca-acidic phospholipid phosphate complexes, probably by competing with Ca for sites on the phospholipid molecules. Once the complexed acidic phospholipids are present, Mg has no effect on the proliferation of hydroxyapatite. This is shown by the invariant first-order rate constant for the disappearance of Ca during hydroxyapatite proliferation (kCa=0.0037 h−1) in solutions with Mg/Ca weight ratios ranging 0/1 to 10/1. These studies suggest that the presence of Mg does affect in vivo calcification and that the initiation of calcification by means of a Ca-PL-PO4 complex may be dependent on the Mg/Ca ratio in the calcifying tissue.
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  • 35
    ISSN: 1432-0827
    Keywords: APD ; Bisphosphonate ; Bone ; Resorption ; Formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dose-related effects of APD on bone metabolism and Ca homeostasis were studied in rats. The experimental approach consisted of longitudinal and cross-sectional observations, aiming at a kinetic interpretation. Bone and cartilage resorption was inhibited within 2–8 days at doses between 0.16 and 16 µmol/kg body weight/day. This was followed by changes in bone apposition that needed at least 23 days for a maximal effect. The time lag created a transient dissociation between resorption and apposition resulting in excess Ca and P retention, adding to increased metaphyseal bone mass. At high doses of APD (≥40 µmol/kg/day) the mineral content of new matrix decreased, associated with impairment of longitudinal growth of long bones. It is concluded that the lower doses of APD inhibited resorption of bone and cartilage, possibly by physicochemical stabilization of bone mineral, whereas the effect on bone apposition was due to a cellular homeostatic mechanism. Inhibition of growth and of matrix calcification, requiring much higher doses, may be due to a direct, toxic effect on bone cells. The modes of action of APD are discussed in relation to EHDP and Cl2MDP.
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  • 36
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    Calcified tissue international 30 (1980), S. 227-232 
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Epiphyseal cartilage ; Calcification ; Alkaline phosphatase
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    Topics: Biology , Medicine , Physics
    Notes: Summary Matrix vesicles isolated from chicken epiphyseal cartilage displayed an uptake of Ca2+ which was linear with time and the amount of vesicle protein. The matrix vesicles stimulated the incorporation of Ca2+ even at very low Ca × P, suggesting that they could bind Ca2+ and/or increase the local Ca × P to the metastable level. This uptake was abolished by EDTA or heating, and partially inhibited by cysteine, to the same extent as the hydrolysis of ATP. There was also a certain uptake of Ca2+ without added phosphate, this being stimulated by ATP up to 3 mmol, but diminishing again with higher concentrations. The presence of ATP failed to stimulate the uptake of Ca2+ more than an equimolar amount of phosphate in the form of inorganic KH2PO4. Mg2+ activated the hydrolysis ofp-nitrophenylphosphate at pH 10.5, and both Mg2+ and Ca2+ the hydrolysis of ATP from pH 7 to 9.5. Paradoxically, the omission of Mg2+ stimulated the uptake of Ca2+ several-fold.
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  • 37
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    Calcified tissue international 30 (1980), S. 15-20 
    ISSN: 1432-0827
    Keywords: Bone ; Osteoclasts ; Macrophage ; Resorption ; Plutonium
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    Topics: Biology , Medicine , Physics
    Notes: Summary Female rats were used to study the kinetics of plutonium transfer from the bone surfaces of the mandibular condyle to osteoclasts and macrophages. This study was made using autoradiographs prepared from plastic sections of the mineralized bones of animals which had been injected with241 Pu citrate. Measurements of the concentration of plutonium in the osteoclasts and macrophages at different times after the injection of plutonium showed that plutonium was concentrated by osteoclasts from bone surfaces and was retained with a half-time of ∼ 70 h. Subsequently, plutonium appeared to be transferred to macrophages. The results showed that plutonium was unlikely to be accumulated by macrophages as a result of their participation in bone resorption.
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  • 38
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    Calcified tissue international 32 (1980), S. 213-219 
    ISSN: 1432-0827
    Keywords: Lactation ; Ca deficiency ; Resorption ; Phosphatases ; cAMP
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    Topics: Biology , Medicine , Physics
    Notes: Summary Lactating female rats were fed diets containing 1.0, 0.1, or 0.04% Ca for 21 days. Fat-free dry weight, ash weight, calcium and phosphorus content of the humerus, plasma calcium levels, and bone acid and alkaline phosphatase activites were compared to those of nonlactating rats fed the same diets. Bone, plasma, and urinary cAMP levels were also studied. Dietary calcium deficiency and/or lactation caused significant loss of bone mass from experimental animals. Urinary cAMP levels reflecting increased parathyroid activity were elevated by the stresses of lactation and calcium deficiency over those of control animals. Plasma and bone levels of cAMP were not different. Bone alkaline and acid phosphatase activities were affected only by the most extreme stress. The results demonstrated that the calcium-deficient lactating rat is an excellent model for bone resorption studies.
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  • 39
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    Calcified tissue international 32 (1980), S. 221-228 
    ISSN: 1432-0827
    Keywords: Medullary bone ; Calcification ; Low-calcium diet ; Parathyroid hormone ; Estrogens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Medullary bone of birds maintained on a low-calcium diet represents a good model to study modifications of matrix composition in calcified tissue undergoing intense formation and resorption. The composition of the bone matrix during the low-calcium diet has been analyzed by both chemical and histological techniques. Sixty White Leghorn pullets 1 year old were used for the experiment. Fifteen birds served as controls and were killed on day zero; the remaining birds were placed on a calcium-deficient diet (0.13% calcium) and sacrificed after 4, 7, and 12 days of treatment in groups of 15. Serum levels of calcium, PTH, and estrogens were also measured. Chemical analysis of the samples were made for total nitrogen, hydroxyproline, hexosamine, hexoses, calcium, and phosphorus. Collagen and proteoglycans of the matrix of medullary bone of the egg-laying hens were found to be affected by the low-calcium diet. They either increased or decreased during the experiment but never in parallel. The increment of serum PTH is considered responsible for the variations in the amount of collagen. The effects of this hormone are magnified by the fall of serum estrogens as shown also by variations in the amounts of noncollagenous protein. In the late phase of the diet the matrix is represented by poorly calcified osteoid tissue rich in noncollagenous protein, i.e., proteoglycans and glycoproteins.
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  • 40
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    Cell & tissue research 211 (1980), S. 303-316 
    ISSN: 1432-0878
    Keywords: Fish scale ; Fine structure ; Development ; Calcification ; Cyprinodon variegatus
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    Topics: Biology , Medicine
    Notes: Summary Scale formation in Cyprinodon variegatus was found to be initiated at about 26 to 30 days after hatching. Ultrastructural investigation revealed that within 4 to 6 h in the first-formed scales the marginal cells begin to flatten and differentiate into osteogenic cells, which later change to osteoblasts and fibroblasts. These cells are separated from the surrounding epithelial cells by a basal lamina. The osteoid is formed by the marginal and osteogenic cells; the osseous layer by the osteoblasts; and the fibrillary plate by the fibroblasts. The osteoid is formed within 2 to 3 h after the initiation of the scale, and within 20 to 24 h the osseous layer is formed. Hydroxyapatite crystals are deposited in the matrix of the osseous layer without apparent association with collagen fibers. No matrix vesicles or dense bodies are evident at the sites of calcification. The fibrillary plate arises 18 to 20 h after the initiation of the scale. It is also partially calcified, but not before the third week of scale formation. The crystals develop almost exclusively between the collagen fibers at the extreme edge of the calcifying front, but solid calcification of the fibers results with further growth of the crystals. The fibroblasts appear to participate in calcification of the fibrillary plate.
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  • 41
    ISSN: 1432-0878
    Keywords: Calcergy ; Calcification ; Cutaneous calcinosis ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary In rats a subcutaneous injection of KMnO4 leads to the calcification of the connective tissue. During mineral deposition, both intra- and extracellular changes are observed in the connective tissue. The intracellular phase is characterized by the formation of intramitochondrial granules and cytoplasmic vesicles, both in fibroblastic and extrinsic cells. In the extracellular phase, numerous heterogeneous matrix vesicles appear in the extracellular matrix. At the same time, globular particles which are resistant to microincineration, are observed between the collagen fibrils. The mineralization of the extracellular matrix takes place in two stages. The first stage comprises the appearance of needle-like structures and round aggregates. The needle-like structures are observed occasionally in the matrix vesicles and often in the extracellular matrix where they appear isolated or diverging from a central point. The round aggregates, composed of dense particles, are seen in the ground substance between the collagen fibrils. The second stage is characterized by a progressive mineralization of the collagen fibrils and the elastic fibers, without formation of extended calcified plaques.
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  • 42
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    Medical & biological engineering & computing 18 (1980), S. 521-526 
    ISSN: 1741-0444
    Keywords: Artificial heart ; Biodegradation ; Biomaterials ; Blood compatibility tests in vitro and in vivo ; Calcification ; Protein adsorption ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Synthetic materials used for medical prostheses and devices, mainly those which will come into contact with blood, have to provide for specific properties. Three in vitro blood-compatibility tests are presented; one is a screening method (m.t.e.g.) whose results show remarkable correlations to in vivo behaviour, the other two (Nosé-blood-chamber, protein adsorption) yield more basis information on synthetic surfaces. Aspects of toxicity and biodegradation should be included in the definition of ‘blood compatibility’. After preselection by in vitro tests, a material has to pass an in vivo examination in animal experiments (shunt, catheter, tube, test chamber) under haemodynamic conditions. Finally, devices or prostheses in their intended shape, such as the total artificial heart, are implanted in animals.
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    Calcified tissue international 3 (1969), S. 363-365 
    ISSN: 1432-0827
    Keywords: Calcification ; Mitochondria ; Protozoa
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  • 44
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    Calcified tissue international 4 (1969), S. 94-100 
    ISSN: 1432-0827
    Keywords: Acid ; Base equilibrium ; Acidosis ; Bone ; Resorption ; Metabolism ; Osteoporosis
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    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'administration chronique de chlorure d ammonium à des rats adultes normaux, soumis à un régime contenant un taux approprié de vitamine D, provoque une ostéoporose. Celle-ci est provoquée par une perte de substance d'os et de minéral osseux, associée à l'augmentation de la résorption osseuse.
    Abstract: Zusammenfassung Chronische Verabreichung von Ammoniumchlorid an normale ausgewachsene männliche Ratten, die eine entsprechende Vitamin-D-haltige Diät erhalten, verursacht die Entwicklung einer Osteoporose. Die Osteoporose entsteht auf Grund eines Verlustes von Knochensubstanz und Knochenmineral, in Begleitung einer erhöhten Knochenresorption.
    Notes: Abstract Excessive administration of ammonium chloride to normal adult male rats receiving a diet adequate in vitamin D caused the development of osteoporosis. The osteoporosis was due to loss of bone substance and bone mineral associated with increased bone resorption.
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    Calcified tissue international 4 (1969), S. 1-12 
    ISSN: 1432-0827
    Keywords: Bone ; Resorption ; Osteocytes ; Lysosomes ; Collagenase
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  • 46
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    Calcified tissue international 4 (1969), S. 339-349 
    ISSN: 1432-0827
    Keywords: Bone ; Resorption ; Calcitonin ; Organ culture
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    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une méthode quantitative pour étudier les effets précoces des hormones et autres agents sur la mobilisation du calcium osseux a été mise au point. Des moitiés de calottes craniennes de souris de 6 jours, ayant reçu du45Ca quatre jours auparavant, sont explantéesin vitro et placées dans des récipients séparés, en milieu liquide; une moitié sert de témoin, l'autre moitié est utilisée pour l'expérimentation. Ce mode d'action dans le temps, de chaque produit testé, est déterminé en prélevant aseptiquement de petits échantillons dans le milieu et en dosant l'isotope. L'hormone parathyroidienne et la vitamine A provoquent une résorption osseuse étendue ainsi qu'un passage augmenté du45Ca des os traités dans le milieu, au bout de 2 heures, si on les compare aux témoins. La calcitonine inhibe rapidement la mobilisation du45Ca des os résorbés: l'intervalle de temps est similaire à celui obtenuin vivo en abaissant le calcium sérique. Nos résultats indiquent que les agents, qui induisent la résorption osseuse, augmentent à la fois le nombre des ostéoclastes et l'efficacité des cellules existantes, en ce qui concerne la mobilisation du calcium. La calcitonine inhibe la libération du45Ca des explants vivants, maintenus dans un milieu contrôle. Cette réduction est attribuée à la suppression de la résorption endogène, en cours au moment de la transplantation: un échange isotopique est toujours observé, comme au niveau des explants sur vivants.
    Abstract: Zusammenfassung Eine quantitative Methode zur Bestimmung der Früheffekte von Hormonen oder andern Wirkstoffen auf die Wanderung von Calcium in den oder aus dem Knochen wurde entwickelt. Calvarien-Hälften von 6 Tagen alten, 4 Tage früher mit45Ca markierten Mäusen werden explantiert und in getrennten Schalen mit flüssiger Nährlösungin vitro belassen. Die eine Hälfte dient als Kontrolle, die andere wird für das Experiment eingesetzt. Anhand kleiner Proben, die den Medien aseptisch entnommen und auf ihren Isotopengehalt geprüft werden, kann die Wirkung der verschiedenen Agentien im Verlaufe der Zeit beobachtet werden. Sowohl Parahormon als auch Vitamin A verursachen eine ausgedehnte Knochenresorption und es wurde, im Vergleich zu den Kontrollen, innerhalb von 2 Std eine gesteigerte Abgabe von45Ca aus den behandelten Knochen in das Medium nachgewiesen, Die Freisetzung von45Ca aus resorbierenden Knochen wird durch Calcitonin rasch inhibiert. Wirkungsweise und Verlauf bestehen, wiein vivo, in einer Senkung des Serum-Calciums. Unsere Resultate zeigen, daß Wirkstoffe, welche eine Knochenresorption veranlassen, sowohl die Zahl der polynucleären Osteoklasten ansteigen lassen als auch die vorhandenen Zellen zur vermehrten Calcium-Mobilisation anregen. Calcitonin dagegen verhindert die Bildung neuer, polynucleärer Osteoklasten wie auch die Mobilisation von Knochenmineral durch die vorhandenen Osteoklasten. Calcitonin wirkt hemmend auf die Abgabe von45Ca von lebenden Explantaten, die in Kontrollmedium kultiviert werden. Diese Abnahme wird der Unterdrückung der endogenen Resorption zugeschrieben, welche im Moment der Knochenexplantation im Gange ist; der Austausch des Isotopes findet weiterhin statt, wie dies bei einem toten Explantat der Fall ist.
    Notes: Abstract A sensitive method has been developed for studying the early effects of hormones and other agents on the movement of calcium into and out of bone. Half-calvariae from 6-day-old mice that have been pulsed four days previously with45Ca, are explanted into separate dishes of liquid medium and maintainedin vitro; one half serves as control and the other for experimentation. The time course of action of any agent is followed by removing small samples aseptically from the media and analysing for isotope. Both parathyroid hormone and vitamin A cause extensive bone resorption, and as compared with controls an increased release of45Ca from the treated bones into the medium can be detected within 2 hours. Calcitonin rapidly inhibits the release of45Ca from resorbing bones; the time course is similar to that for its actionin vivo in lowering serum calcium. Our results indicate that agents that induce bone resorption increase both the number of multinucleate osteoclasts and the effectiveness of the existing cells in mobilising calcium. Calcitonin prevents the formation of new multinucleate osteoclasts, and also prevents existing osteoclasts from mobilising bone mineral. Calcitonin inhibits the release of45Ca from living explants maintained in control medium. This reduction is attributed to the suppression of the endogenous resorption that is in progress when the bones are explanted; exchange of isotope still occurs, as in a dead explant.
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  • 47
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    Calcified tissue international 4 (1969), S. 101-112 
    ISSN: 1432-0827
    Keywords: Calcification ; Ligament ; Mollusc ; Aragonite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Une étude de microscopie électronique est réalisée sur la formation et la structure du ligament interne deMytilus edulis etPinctada radiata. Cette partie du ligament est dérivée des cellules isthmiques qui sont de forme cylindrique irrégulière. Elles présentent un ergastoplasme bien développé et un appareil de Golgi, engagé dans l'élaboration de vésicules et granules qui s'incorporent au niveau de la conchioline. Les cristaux se forment au niveau du front de calcification, à la surface interne du ligament. Ils sont entourés par une enveloppe. Ils se présentent comme des monocristaux d'aragonite, allongés et en forme d'aiguilles, dispersés dans le ligament. Bien que les constituants de la carapace et du ligament soient identiques, il existe des différences concernant l'augmentation quantitative de conchioline et une diminution en nombre, forme diverse, groupement et croissance des cristaux. Ces différences sont probablement liées à la fonction spécialisée du ligament.
    Abstract: Zusammenfassung Die Bildung und Struktur des inneren Ligamentes vonMytilus edulis undPinctada radiata wurden am Elektronenmikroskop untersucht. Dieser Teil des Ligamentes stammt von den Isthmuszellen ab, deren Form unregelmäßig säulenartig ist. Sie zeigen ein vorspringendes, rauhes endoplasmatisches Reticulum und einen Golgiapparat, welche sich mit der Bildung von Bläschen und Granula befassen, die schließlich in einem integralen Teil des Conchiolins eingebaut werden. Die Kristalle entstehen an der Calcifikationsgrenze an der inneren Oberfläche des Ligamentes und sind in Hüllen eingeschlossen. Sie bestehen aus langen, nadelförmigen, einzelnen Aragonit-Kristallen, die über das ganze Ligament verteilt sind. Obschon die Bestandteile der Muschel und des Ligamentes gleichartig sind, unterscheiden sich die beiden durch eine erhöhte conchiolinmenge, wie auch durch eine Abnahme der Anzahl der Kristalle, welche verschieden in der Form, in der Anordnung und im Wachstum sind. Dies alles ist vermutlich auf die spezielle Funktion des Ligamentes zurückzuführen.
    Notes: Abstract An electron microscope study was made of the formation and structure of the inner ligament ofMytilus edulis andPinctada radiata. This part of the ligament is derived from the isthmus cells which are irregular columnar in shape. They exhibit a prominent rough endoplasmic reticulum and a Golgi apparatus, which are concerned with the elaboration of vesicles and granules eventually incorporated into an integral part of the conchiolin. The crystals arise at the calcification front at the inner surface of the ligament and are enclosed in envelopes. They consist of long, needle-shaped, single aragonite crystals widely dispersed in the ligament. Although the components of the shell and ligament are similar, differences between them consist of an increased amount of conchiolin, as well as a decrease in the amount, diversity of form, arrangement and growth of the crystals; all probably related to the specialized function of the ligament.
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    Calcified tissue international 4 (1969), S. 162-173 
    ISSN: 1432-0827
    Keywords: Bone ; Resorption ; Parathyroid ; Bird
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'os médullaire des poules au moment de la ponte ainsi que l'os néoformé de coqs soumis à des substances oestrogéniques, ont été examinés par les méthodes de l'histologie, de l'histochimie, de la microradiographie et de l'alpharadiographie afin de comparer la résorption naturelle à celle produite par la parathormone. Chez les pondeuses, la résorption a été provoquée par la formation de la coquille; chez les coqs, elle s'est produite à la suite de la diminution du taux des oestrogènes. La résorption naturelle de l'os médullaire a été marquée par un accroissement de la basophilie, de l'azurophilie et de la metachromasie, par la diminution graduelle de la densité organique et minérale. Ces modifications ont été observées d'abord dans la portion distale de l'os médullaire; elles se sont progressivement propagées à la région sous corticale. L'extrait parathyroidien semble avoir favorisé tous ces phénomènes, en stimulant l'ostéolyse ostéocytaire et l'ostéoclasie. Il ne nous a pas été possible cependant de nous rendre compte si les ostéoclastes ne se sont attaqués qu'aux portions des travées déja modifiées par l'ostéolyse. Ces résultats concordent avec l'idée que la résorption normale de l'os médullaire de la poule au temps où la coquille de l'oeuf se dépose, est déclanchée par la parathormone. Il en est de même chez le coq à la suite du retrait des oestrogènes.
    Abstract: Zusammenfassung Die Substantia spongiosa der Femora von Legehennen und von Hähnen die mit Östrogen behandelt waren, wurde während spontaner und künstlicher, mit Extrakten von Epithelkörperchen induzierter, Resorption einer histologischen, histochemischen, alpharadiographischen und mikroröntgenographische Untersuchung unterworfen. Die natürliche Resorption wurde bei den Hennen durch die Eischalenproduktion und bei den Hähnen durch Östrogenentzug hervorgerufen. Die natürliche Resorption war durch erhöhte Basophilie, Azurphilie und Metachromasie, sowohl als auch durch verminderter alpharadiographischer und mikroröntgenographischer Dichte der Trabeculae der Substantia spongiosa charakterisiert. Diese Veränderungen wurden zuerst in den zentralen, dem Cavum medullare nächstgelegenen, Teilen der Spongiosa wahrgenommen. Später waren auch die peripheren Teile, mit geringerer Osteocytenkonzentration, betroffen. Diese Veränderungen konnten durch Gaben von Epithelkörperchenextrakten verstärkt werden. Die Resorption der Spongiosa wird durch osteocytische Osteolyse und Osteoklasie bewirkt. Es konnte aber nicht entschieden werden ob diese beiden Prozesse gleichzeitig stattfinden, oder ob die Osteoklasten die Trabeculae erst angreifen, nachdem sie bereits teilweise durch Osteolyse abgebaut worden sind. Diese Resultate stimmen mit der Hypothese überein, daß die natürliche Resorption von Spongiosa während der Eischalenproduktion bei Hennen und nach Entzug von Östrogen bei Hähnen, durch Epithelkörperchenhormonen bedingt ist.
    Notes: Abstract The medullary bone in the femora of laying hens and of oestrogen-treated cocks has been examined by histological, histochemical, alpharadiographic and microroentgenographic techniques while undergoing both natural resorption and resorption induced by injection of parathyroid extract. In the hens, natural resorption was brought about by egg-shell formation and in the cocks by withdrawal of oestrogen. Natural resorption was accompained by increasing basophilia, azurophilia and metachromasia and by decreasing alpharadiographic and microradiographic density of the trabeculae of the medullary bone. These changes were observed initially in the central region (towards the marrow cavity) and subsequently in the peripheral regions also, where the number of osteocytes per unit area of bone was less. Parathyroid extract enhanced all these effects. It appears that resorption of medullary bone was brought about by osteocytic osteolysis and by osteoclasis, but it was not possible to determine whether both processes occurred concurrently or whether the osteoclasts attacked the trabeculae only after they had been partially degraded by osteolysis. These results are consistent with the hypothesis that the natural resorption of medullary bone during egg-shell formation in hens and following the withdrawal of oestrogen in cocks is induced by parathyroid hormone.
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    Calcified tissue international 4 (1969), S. 291-304 
    ISSN: 1432-0827
    Keywords: Bone ; Fluorescence ; Resorption ; Deposition ; Calcium ; Microradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Divers agents chimiques, colorés, fluorescents et se localisant dans les os, à savoir la tétracycline, l'alazazine rouge S et le DCAF, ont été administré en série à des rats sevrés et on a mesuré le taux de la formation et de la résorption osseuse sur les coupes transversales du tiers supérieur de la diaphyse. Ici la formation osseuse périostale s'effectue progressivement avec peu de changement endostéal. Avec alimentation carnée, la croissance des rats est significativement restreinte pendant la première semaine, mais se rétablit ensuite. Bien qu'il y ait croissance des os, ceux-ci ne se minéralisent pas normalement et ils deviennent rapidement fragiles et amincis. La résorption osseuse est lente d'abord, puis s'accelère pendant 2–3 semaines pour atteindre un taux de 15μ par jour, après quoi elle se ralentit de nouveau. Bien que le taux de formation osseuse soit réduit, en comparaison avec celui des os normaux, la résorption s'effectue environ deux à trois fois plus rapidement que la croissance osseuse. Des études microradiographiques sur des rats à régime carné mais carencés en calcium ont permis la constatation suivante: tandis que la résorption s'effectue à la marge endostéale et que la formation osseuse a lieu sur l'aspect périostéal, la matière osseuse nouvellement formée est moins calcifiéc que chez les témoins.
    Abstract: Zusammenfassung Einige farbige, fluoreszierende, knochensuchende Chemikalien, z. B. Tetracyclin, Alazarin-Rot S und CDAF, wurden nacheinander an entwöhnten Ratten verabreicht, worauf man die Knochenbildungs- und Knochenresorptionswerte an hartgeschliffenen Schnitten des oberen Drittels der Diaphyse gemessen hat. Hier findet fortschreitend periostale Knochenbildung statt, mit geringer Veränderung des Endosteums. Bei Fleischdiät wird das Körperwachstum während der ersten Woche erheblich beschränkt; danach aber normalisiert es sich wieder. Obwohl die Knochen noch wachsen, zeigen sie keine normale Mineralisierung und werden schnell zerbrechlich und dünn. Die Knochenresorption ist anfangs langsam, dann beschleunigt sie sich während einer Zeitspanne von 2–3 Wochen bis auf 15 μ pro Tag, um sich dann wieder zu verlangsamen. Während die Knochenbildungsgeschwindigkeit relativ zum Normalwert heruntergesetzt wird, verläuft die Resorption ungefähr 2–3mal so schnell wie die Knochenbildung. Mikroradiographische Untersuchungen an mit Fleisch ernährten Ca-armen Ratten haben bestätigt, daß während die Resorption am Endosteumrande stattfindet und sich die Knochenbildung an der Periostenfläche fortsetzt, die neugebildete Knochensubstanz weniger kalzifiziert ist, als die der Kontrolltiere.
    Notes: Abstract Different coloured, fluorescent bone-seeking chemicals, viz., tetracycline, Alizarin Red S, and DCAF, have been administered sequentially to weanling rats and the rate of formation and resorption of bone measured from hard-ground cross sections of the upper third of the diaphysis of the femur. On a meat diet, bodily growth is significantly restricted for the first week and then recovery occurs. While bones grow they fail to mineralize normally and rapidly become fragile and rarefied. Resorption of bone is at first slow, then accelerates for a period of 2–3 weeks to about 15μ/day and then slows again. While the rate of bone formation is reduced relative to normal bone, resorption proceeds at approximately two to three times the rate of bone growth. Microradiographic studies confirm tht while resorption occurs on the endosteal margin and formation proceeds on the periosteal aspect of meat fed Ca-deficient rats, new bone is less calcified than that in control animals.
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    Calcified tissue international 4 (1969), S. 359-365 
    ISSN: 1432-0827
    Keywords: Metals ; Ions ; Buffers ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'action de divers ions métalliques polyvalents sur les propriétés métastables d'un tampon calcifiable a été étudiée. A des concentrations de 1 μM ou moins, les ions Pb2+, F2+, Fe3+, Cr3+, Bi3+ et Al3+ déstabilisent le tampon. Il semble que les phosphates insolubles formés par ces ions déclanchent la précipitation de l'apatite. L'importance de ces résultats dans l'étiologie des calcifications pathologiques et la calciphylaxie est décrite.
    Abstract: Zusammenfassung Die Wirkung von verschiedenen polyvalenten Metallionen auf die Metastabilität eines Calcifikationspuffers wurde untersucht. Bei Konzentrationen von 1 μM oder weniger wird der Puffer durch Pb2+, Fe2+, Fe2+, Cr3+, Bi3+ und Al3+ entstabilisiert. Die Resultate lassen vermuten, daß unlösliche Phosphate, die mit diesen Ionen entstehen, eine Fällung von Apatit veranlassen. Die Bedeutung dieser Befunde bei pathologischen Verkalkungen und Calciphylaxis werden besprochen.
    Notes: Abstract The effect was studied of various polyvalent metal ions on the metastability of a calcification buffer. At concentration of 1 μM or less, Pb2+, Fe2+, Fe3+, Cr3+, Bi3+ and Al3+ ions were found to destabilize the buffer. The results suggest that insoluble phosphates formed by these ions initiate the precipitation of calcium apatite. The implications of these findings to pathological calcification and calciphylaxis are discussed.
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    Calcified tissue international 3 (1969), S. 308-317 
    ISSN: 1432-0827
    Keywords: Bone ; Enamel ; Hydroxyapatite ; X-ray Diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'objet de cette étude a été de déterminer l'effet du mode de préparation (par meulage) sur la largeur des raies de diffraction de l'émail. La préparation d'émail, par meulage, en utilisant divers procédés ainsi qu'une pièce à main dentaire conventionnelle provoque un élargissement des pics obtenus (002, 211, 200 et 202) lorsqu'on la compare avec de la poudre d'émail, obtenue par meulage à l'aide de billes. L'élargissement des raies n'est pas observé lorqu'un monocristal d'hydroxylapatite est meulé à l'aide d'un diamant fin. En général, l'élargissement est moins important, lorsque le meulage est effectué à l'aide de turbines dentaires. L'importance du meulage dépend de façon variable d'un ou plusieurs des facteurs suivants: rugosité des instruments coupants, vitesse de meulage, direction de meulage, et la présence ou l'absence d'eau. Le meulage prolongé par billes de l'émail provoque aussi un élargissement dans les mêmes conditions, cependant, l'os n'est pas endommagé. Ces résultats indiquent que l'émail est plus sensible que l'hydroxylapatite et l'os. L'élargissement de raies peut être dû soit à une déformation de la maille cristalline, soit à une diminution de taille des cristaux.
    Abstract: Zusammenfassung Es wurde eine Untersuchung durchgeführt, um den Einfluß der Probenvorbereitung (Zerreibungsmethode) auf die Breite des Linienprofil-Querschnittes von Zahnschmelz zu bestimmen. Gewinnung von Zahnschmelz mit den verschiedenen Schneidinstrumenten einer konventionellen Bohrmaschine verursachte eine Verbreiterung aller untersuchten Peaks (002, 211, 200 und 202) im Vergleich zum gleichen Schmelz, der mit dem Rosenbohrer zerrieben wurde. Eine Verbreiterung der Linie konnte nicht beobachtet werden, wenn ein einzelner Kristall von Hydroxyapatit mit einem ganz feinen Diamanten zerrieben wurde. Im allgemeinen war die Verbreiterung weniger ausgesprochen, wenn die hochtourige Bohrtechnik zur Anwendung kam. Das Ausmaß der Verbreiterung, das durch Zahnbohrer verursacht wurde, war abhängig von einem oder mehreren der folgenden Faktoren: Rauheit des Schneidinstrumentes, Zerreibungsgeschwindigkeit, Zerreibungsrichtung und das Vorhandensein oder Fehlen von Wasser. Verlängerte Zerreibung von Schmelz mit dem Rosenbohrer verursachte ebenfalls eine Verbreiterung. Unter identischen Bedingungen blieb der ausgeglühte Knochen jedoch unversehrt. Diese Beobachtungen zeigen, daß Schmelz für Zerreibungsschäden anfälliger ist, als Hydroxyapatitkristalle oder ausgeglühter Knochen. Die eigentliche Ursache der Linienverbreiterung kann entweder eine Schädigung infolge Distortion des Gitters oder eino Reduktion der Größe der individuellen Kristalle sein.
    Notes: Abstract A study was conducted to determine the effect of sample preparation (grinding method) upon breadth of the diffraction profile of enamel. Collecting enamel by grinding with various cuttin tools in the low-speed dental handpiece caused broadening of all peaks (002, 211, 300 and 202) examined, compared to ball, ground, counter-part enamel. Line broadening was not observed when a single crystal of mineral hydroxyapatite was ground with a very fine diamond. In general, broadening was less pronounced with the high-speed air turbine technique. The amount of broadening caused by dental burs depended upon one or more of the following factors: coarseness of cutting instrument, grinding speed, grinding direction, and the presence or absence of water. Prolonged ball grinding of enamel also caused broadening; under identical conditions, however, annealed bone remained undamaged. These findings indicate that enamel is more sensitive to grinding damage than the mineral hydroxyapatite crystal or annealed bone. The actual cause of line broadening may be either strain due to lattice distortions or a reduction in size of individual crystallites.
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    Calcified tissue international 3 (1969), S. 38-54 
    ISSN: 1432-0827
    Keywords: Epiphyseal cartilage ; Calcification ; Apatite crystals ; Organic/Inorganic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les rapports entre composants organiques et inorganiques du cartilage ont été étudiés au niveau des épiphyses tibiales chez des rats de 5 jours et au niveau des jonctions costo-chondrales chez des cobayes d'un mois. Voici les principaux résultats auxquels on est parvenu: (a) Dans les zones où la calcification s'amorce les cristallites d'apatite sont susceptibles d'être facilement éliminés des coupes en araldite et en glycol methacrylate (GMA) après traitement pendant une heure par une solution d'acide formique au 2%. (b) Les zones décalcifiées sont douées d'une faible densité aux électrons et vont exemptes d'une structure quelconque. Seulement la fixation à l'osmium peut révéler du matériel amorphe. (c) Indépendemment du fixateur et du moyen d'inclusion, les coupes décalcifiées, traitées par l'acétate d'uranyl et/ou par le citrate de plomb, montrent de fines structures allongées dont l'aspect est semblable à celui des cristallites. (d) Ces structures ainsi qu'un fond dense interposé prennent l'acide phosphotungstique (PTA) dans les coupes en GMA, une méthode celle-ci qui met en évidence les polysaccharides. (e) Le fond dense ne prend plus le PTA après traitement par la hyaluronidase et en même temps les structures semblables au cristallites apparaissent plus faibles. Après traitement par l'acétate d'uranyl et le citrate de plomb, l'attaque par la hyaluronidase ne produit aucune modification appréciable. Au contraire l'aspect des structures semblables aux cristallites apparait modifié par la digestion à la papaïne. (f) Quand la décalcification à l'EDTA précéde l'enrobage, des amas de matériel fibrillaire se mettent en évidence dans les zones où la calcification s'était amorcée. L'ensemble de ces résultats permet d'établir la nature organique des structures semblables au cristallites et porte aussi à admettre que celles-ci soient formées par de fins filaments cylindriques (digérés par la papaïne) entourés, et probablement engainés par del polysaccharides (digérés par la hyaluronidase et prennant le PTA dans les coupes en GMA).
    Abstract: Zusammenfassung Die Wechselbeziehungen zwischen den organischen und inorganischen Substanzen des verkalkenden Knorpels wurden in der tibialen und femuralen Epiphyse 5 Tage alter Ratten und in den Rippen 1 Monat alter Meerschweinchen untersucht. Die Hauptergebnisse waren: a) Die Hydroxyapatitkristalle der Frühverkalkungszonen können in Araldit- wie auch in Glycolmethylacrilatschnitten (GMA) mit einer lstündigen Behandlung durch 1% ige Ameisensäure leicht entfernt werden. b) Die entkalkten Zonen haben eine sehr niedrige Elektronendichte und enthalten keine sichtbaren Festkörper. Nach Fixierung mit Osmiumsäure kann man darin ein formloses Material erkennen. c) Eine Färbung der Schnitte mit Uranacetat und Bleicitrat, welche von den Fixier- und Einbettungsmitteln nicht beeinträchtigt wird, zeigt feine, längliche Körper (“Kristallgeister”) an, welche morphologisch den Kristallen von Hydroxyapatit gleichen. d) Die Färbung der GMA-Schnitte mit Phosphowolframsäure (PWS), eine Methode welche Polysaccharide anzeigt, hob diese “Kristallgeister” besonders hervor und demonstrierte auch eine dichte dazwischenliegende Grundsubstanz. e) Diese Substanz ist nach Behandlung mit Hyaluronidase nicht mehr färbbar mit PWS; die Färbbarkeit der “Kristallgeister” wird dabei jedoch nur verringert. Die Hyaluronidasebehandlung verändert die Uranacetat- und Bleicitratfärbung nicht. Die Feinstruktur der “Kristallgeister” wird durch Papainbehandlung sehr angegriffen. f) Falls die Schnitte vor dem Einbetten mit EDTA entkalkt werden, können Faserbündel in den Frühzonen der Verkalkung nachgewiesen werden. Diese Ergebnisse bestätigen die organische Natur der “Kristallgeister”. Sie beweisen auch, daß dieselben aus feinen Proteinstäbchen bestehen (verdaulich in Papain) und von Polysacchariden umgeben und vielleicht auch überzogen sind (verdaulich in Hyaluronidase und anfärbbar mit PWS).
    Notes: Abstract The organic/inorganic relationships in calcifying cartilage have been studied in tibialfemoral epiphyses of 5-day-old rats and in costochondral junctions of 1-month-old guinea pigs. The main results are: (a) Apatite crystallites in areas of early cartilage calcification are easily removed from araldite and glycol methacrylate (GMA) sections by 1-hour treatment with 2% formic acid. (b) The decalcified areas have a very low electron density and do not contain recognizable structures. Only after osmium fixation can an amorphous material be found in them. (c) Independently from the fixative and the embedding medium, staining decalcified areas with uranyl acetate and/or lead citrate reveals thin, elongated structures (crystallite ghosts) similar in shape to apatite crystallites. (d) These crystallite ghosts and a dense background are stained by phosphotungstic acid (PTA) in GMA sections, a method which reveals polysaccharides. (e) The dense background is no longer stained by PTA after hyaluronidase digestion and the stainability of the crystallite ghosts is reduced. After uranyl acetate/lead citrate staining there are no recognizable changes due to hyaluronidase. But, on the other hand, the fine structure of the crystallite ghosts is modified by papain digestion. (f) Clusters of fibrillar material are present in the areas of early calcification when EDTA decalcification is carried out before embedding the specimens. These results confirm the organic nature of the crystallite ghosts and suggest that they are formed by thin, rod-like protein/like structures (digested by papain) surrounded, and probably sheathed, by acid polysaccharides (digested by hyaluronidase and stained by PTA in GMA sections).
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    Calcified tissue international 4 (1969), S. 20-38 
    ISSN: 1432-0827
    Keywords: Calcification ; Epiphyseal Cartilage ; Bone ; Electrolytes ; Organic matrices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un procédé de dissection a été mis au point pour permettre l'analyse zonale du cartilage de l'épiphyse des os de la jambe d'un foetus bovin. Des échantillons de tissu complet et lavé venant des différentes zones ont été analysés pour déterminer leur contenu en électrolyte et en constituants organiques, ainsi que pour leur densité, cendres et humidité. Les résultats ont montré que lorsque la quantité de cendres et la densité augmentaient, l'eau contenu dans le tissu diminuait. Les quantités de cendres dans les zones de cartilage en voie de calcification étaient plus grandes qu'il avait été. Quand elles étaient exprimées comme un pourcentage du poids sec, elles étaient les plus importantes dans le cartilage lavé calcifié que dans le autre zones. Au début de la minéralisation du cartilage, la quantité de Na (m moles/l de tissu frais) diminuait tandis que celles du Ca et du P inorganique augmentaient. Les niveaux de Mg augmentaient pendant que la calcification se poursuivait, mais seulement à une faction du taux du Ca et du P. Les rapports Ca/P inorganique étaient les plus grands dans le cartilage au repos (Cartilage non-différentié hyalin), suggérant un lien initiale entre Ca et les chrondromucoprotéines. Cependant, au début de la calcification, pendant la prolifération du cartilage les rapports Ca/P étaient beaucoup plus petits (ca. 1.50) mais augmentaient graduellement avec l'advancement de la minéralisation. Des changements importants survenaient dans la composition de la phase organique, pendant la calcification endochondrale. Comme il a été déterminé par l'analyse de l'hydroxyproline la quantité de collagéne diminuait progressivement pendant la calcification du cartilage, mais augmentait rapidement pendant la formation d'os. Comme il a été déterminé par l'analyse de l'héxosamine et du sulfute les chrondromucoprotéines étaient aux niveaux les plus éléves pendant la prolifération du cartilage et diminuaient constamment au cours de la calcification. Cependant, bien que la calcification était déja très avancée dans le cartilage hypertrophique, de grandes quantites de mucopolysaccharides étaient encore présentes. Les rapports sulfure/hhéxosamine montraient un léger déclin pendant les premiéres étapes de la calcification, mais augmentaient beaucoup pendant le cours de la minéralisation. Les quantités d'acide sialique étaient plus grandes dans le cartilage de l'épiphyse que dans le cartilage au repos ou dans l'os. Les lipides augmentaient rapidement pendant la calcification du cartilage, mais étaient très réduites dans l'os complètement formé. La signification de ces résultats est discutée.
    Abstract: Zusammenfassung Eine Seziermethode, die eine Schichten-Analyse der Beinepiphysenplatte von Rinderfeten erlaubt, wurde entwickelt. Proben vor und nach Waschen des Gewebes der verschiedenen Schichten werden untersucht in bezug auf Elektrolyte und organische Bestandteile, als auch in bezug auf Dichte, Aschengehalt und Feuchtigkeit. Die Resultate zeigten eine Zunahme des Aschengehaltes und der Dichte, während der Wassergehalt abnahm. Unerwartet hoch waren die Aschenwerte im in Verkalkung begriffenen Knorpel. Ausgedrückt in Prozent Trockengewicht, ergab gewaschener, verkalkter Knorpel den höchsten Wert aller Zonen. In den Frühstadien der Knorpelmineralisation nahm der Natriumgehalt (m Mol/l Frischgewebe) ab, während Ca und anorganischer P zunahmen. Mit fortschreitender Verkalkung erhöhte sich auch der Magnesium-Spiegel, allerdings nur zu einem Bruchteil des Ausmaßes, in welchem Ca und P zunahmen. Die höchsten Ca/P anorg. Verhältnisse wurden im Ruheknorpel (undifferenzierter hyaliner Knorpel) gefunden, was auf eine initiale Bindung von Ca durch Chondromucoproteine hinweist. Die Ca/P-Verhältnisse proliferierenden Knorpels waren jedoch bei Verkalkungsbeginn viel tiefer (ca. 1.50). Diese nahmen allerdings mit fortschreitender Mineralisierung stetig zu. In der endochondralen Verkalkungsphase fanden markante Veränderungen in der Zusammensetzung des organischen Anteils statt. Basierend auf der Hydroxyprolinanalyse nahm der Collagengehalt in der knorpeligen Verkalkungsperiode fortschreitend ab, während er jedoch bei der Knochenbildung rasch zunahm. Die an Hand von Hexosamin- und Schwefelanalysen bestimmten Chondromucoproteingehalte ergaben Höchstwerte im proliferierenden Knorpel und fielen stetig ab mit zunehmender Verkalkung. Trotz der im hypertrophischen Knorpel schon weit fortgeschrittenen Verkalkung waren immer noch große Mengen an Mucopolysacchariden vorhanden. Die Schwefel/Hexosamin-Verhältnisse zeigten eine minimale Abnahme in den frühen Verkalkungsphasen, nahmen jedoch markant zu bei fortschreitender Mineralisation. Der Sialinsäurespiegel war im Epiphysenknorpel, verglichen mit demjenigen des Ruheknorpels oder Knochens, erhöht. In der knorpeligen Verkalkungsphase nahmen die Lipide rasch zu, während jedoch die Werte des vollständig ausgebildeten Knochens stark vermindert waren. Die Bedeutung dieser Ergebnisse wird besprochen.
    Notes: Abstract A dissection procedure has been devised to permit zonal analysis of the epiphyseal plate of fetal calf leg bones. Samples of whole and washed tissue from the various zones were analyzed for their content of electrolyte and organic constituents, as well as for density, ash and moisture. Results showed that as ash content and density increased, water content decreased. Ash levels in calcifying cartilage zones were unexpectedly high. When expressed as a percentage of dry weight, washed calcified cartilage had the highest content of any zone. In the early stages of the mineralization of cartilage, Na content (mmoles/l of fresh tissue) decreased as Ca and inorganic P increased. Magnesium levels increased as calcification proceeded, but only at a fraction of the rate of Ca and P. Ratios of Ca/inorganic P were highest in resting cartilage (non-differentiated hyaline cartilage), suggesting an initial binding of Ca to chondromucoproteins. However, at the onset of calcification in proliferating cartilage, Ca/P ratios were much lower (ca. 1.50), but gradually increased with advancing mineralization. Marked changes occurred in the composition of the organic phase during endochondral calcification. As determined by hydroxyproline analysis, collagen content progressively decreased during cartilaginous calcification, but increased rapidly during bone formation. As determined by hexosamine and sulfur analysis, chondromucoproteins were at highest levels in proliferating cartilage and decreased steadily as calcification increased. However, although calcification was already well advanced in hypertrophic cartilage, large amounts of mucopolysaccharide still were present. Sulfur/hexosamine ratios showed a slight decline during the early stages of calcification, but increased markedly with further mineralization. Sialic acid levels were elevated in epiphyseal cartilage over those in resting cartilage or bone. Lipids increased rapidly during cartilaginous calcification, but were greatly reduced in fully-formed bone. The significance of these findings is discussed.
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    Calcified tissue international 3 (1969), S. 184-193 
    ISSN: 1432-0827
    Keywords: Mitochondria ; Calcification ; Calcium ; Chondrocytes ; Growth plate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cultures d'épiphyse prélevées sur des rats et des souris ont été étudiées sous le microscope électronique. Un profile de granules mitochondriques de densité électronique a été trouvé. Les chondrocytes dans la zone proliférative avaint peu de granules, alors que ceux des zones successives ont montré une augmentation progressive de leur nombre et densité jusqu'à ce que la zone de calcification provisoire ait été atteinte. Cette zone a montré une distribution périphérique de mitochondries et une réduction du nombre et de la densité des granules mitochondriques. Du calcium isotopique 47 a été utilisé autoradiographiquement pour déterminer la location de calcium dans ces cellules. Des grains ont été trouvés sur les membranes R.E. et sur la plupart des mitochondries. La preuve d'un profile de ces granules et de leur rapport spatial avec la face de minéralisation indique une action éventuelle de mitochondries dès le début de la calcification de la matrice.
    Abstract: Zusammenfassung Epiphysekulturen von Ratten und Mäusen wurden unter dem Elektronenmikroskop untersucht. Ein Profil von mitochondrischen Körnchen mit elektronischer Dichte wurde gefunden. Chondrozyten in der Proliferationszone wiesen wenig Körnchen auf, während die der nachfolgenden Zonen allmählich an Zahl und Dichte zunahmen, bis die Zone der provisorischen Verkalkung erreicht wurde. Diese Zone zeigte eine periphere Verteilung der Mitochondrien und eine Abnahme in Zahl und Dichte der mitochondrischen Körnchen. Isotopes Kalzium 47 wurde autoradiographisch verwendet, um die Lage des Kalziums in diesen Zellen zu bestimmen. Körnchen wurden auf den E.R.-Membranen und auf einem Großteil der Mitochondrien gefunden. Der Nachweis eines Profils dieser Körnchen und ihres räumlichen Verhältnisses zur Mineralisierungsfläche weist auf einen möglich Einfluß der Mitochondrien mit Beginn der Matrixverkalkung hin.
    Notes: Abstract Rat and mice epiphyseal growth plates were studied with the electron microscope. A gradient of mitochondrial electron-dense granules was found. Chondrocytes in the proliferative zone had few granules, while those of the succeeding zones showed a gradual increase in number and density until the zone of provisional calcification was reached. This zone showed a peripheral distribution of mitochondria and a decrease in the number and density of mitochondrial granules. Isotopic47calcium was used autoradiographically to determine the location of calcium in these cells. Grains were found over the endoplasmic reticulum membranes and over most mitochondria. The demonstration of a gradient of these granules and their spatial relation to the mineralization front suggests a possible involvement of mitochondria in the onset of matrix calcification.
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    Calcified tissue international 4 (1969), S. 78-83 
    ISSN: 1432-0827
    Keywords: Bone ; Calcification ; Osteomalacia ; Phosphorus ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les effects d'une dose de 1 mg de vitamine D3 (40 000 Unités,) administrée par voie intra-veineuse, ont été étudiés sur l'histologie osseuse et le métabolisme du phosphore chez 19 sujets contrôles dont l'histologie était normale et 28 malades présentant les caractères histologiques de l'ostéomalacie par carence vitaminique D. L'administration de la vitamine D n'a entraîné aucune modification histologique ou biologique significative chez les sujets contrôles. Mais chez les ostéomalaciques, il est apparu en moins de sept jours une augmentation très significative du front de calcification à l'interface tissue-ostéoïde-tissue-calcifié. Cette modification s'accompagnait d'une ascension progressive de la phosphatémie et de la réabsorption tubulaire du phosphore atteignant dans le même délai des valeurs normales.
    Abstract: Zusammenfassung Bei 19 Patienten mit normaler Knochenhistologie und bei 28 Patienten mit histologisch gesicherter Osteomalacie wurde die Wirkung von 1 mg Vitamin D3 (40000 Iv) i.v. auf die Knochenhistologie und den Phosphatmetabolismus untersucht. Bei den Kontrollpatienten konnten keine signifikanten Änderungen nach Vitamin D festgestellt werden, wogegen die Osteomalacie-patienten innerhalb von 7 Tagen eine deutliche Zunahme der Verkalkungszone an der Grenze zwischen Osteoid- und Knochengewebe zeigten. Diese Änderung war von einer fortschreitenden Zunahme des Serum-Phosphates, verbunden mit einer gesteigerten renalen tubulären Rückabsorption des Phosphates begleitet; beide kehrten anschließend gleichzeitig wieder zur Norm zurück.
    Notes: Abstract The effect of a 1 mg dose of intravenous Vitamin D3 (40,000 i.u.) on bone histology and phosphate metabolism was investigated in 19 patients with normal bone histology and 28 patients with histological evidence of osteomalacia. No significant changes occurred in the control patients after Vitamin D but the patients with osteomalacia showed a marked increase, within seven days, in the proportion of osteoid having a calcification front. This was accompanied by a progressive rise in the serum phosphate, which was associated with an increase in the renal tubular reabsorption of phosphate to normal.
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    Calcified tissue international 4 (1969), S. 129-135 
    ISSN: 1432-0827
    Keywords: Immunology ; Embryo ; Bovine ; Enamel ; Matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé De l'amélogénine bovine, matrice organique secrétée par les cellules formant l'émail dentaire, est antigénique chez le lapin. La fraction purifiée de gamma-globuline de l'antisérum de lapin, en présence d'amélogénine, dans une boite d'agar à double diffusion, provoque une ligne simple de précipitine. Des fractions isolées de l'amélogénine, par électrophorèse sur gel d'acrylamide et par filtration sur gel de Sephadex, semblent identiques au point de vue antigénique. La fraction antigénique d'amélogénine est séparée de la protéine de l'émail à l'aide d'une colonne Sephadex G-100. L'amélogénine est un système complexe, si l'on se réfère aux résultats d'électrophorèse et de filtration sur gel: ai point de vue immunologique, l'amélogénine se comporte comme un antigène simple.
    Abstract: Zusammenfassung Rinder Amelogenin, die organische Matrix, welche durch die Zahnschmelz-bildenden Zellen sezerniert wird, wirkt als Antigen auf das Kaninchen. Die gereinigte Gammaglobulinfraktion des Kaninchen-Antiserums ergibt auf einer Doppel-Diffusions-Agarplatte eine einzelne Koagulinlinie, wenn sie mit Amelogenin reagiert. Unterfraktionen aus Amelogenin isoliert durch Acrylamid-Gel-Elektrophorese und durch Sephadex-Gel-Filtration wurden in ihrer Antigen-Wirksamkeit identisch gefunden. Die Antigen-Fraktion von Amelogenin wurde durch eine Sephadex G-100-Säule von der Gesamtmenge des Zahnschmelz-Proteins getrennt. Auf Grund seiner bei der Elektrophorese und der Gel-Filtration beobachtetem Eigenschaften ist Amelogenin ein aus verschiedenen Komponenten zusammengesetztes System; Amelogenin wirkt jedoch immunologisch als ein einzelnes Antigen.
    Notes: Abstract Bovine amelogenin, the organic matrix secreted by the dental-enamel-forming cells, is antigenic in the rabbit. The purified gamma globulin fraction of the rabbit antisera when reacted with amelogenin in a double diffusion agar plate forms a single precipitin line. Subfractions isolated from amelogenin by acrylamide gel electrophoresis and by Sephadex gel filtration were found to be antigenically identical. The antigenic fraction of amelogenin was separated from the bulk of the enamel protein by a Sephadex G-100 column. On the basis of its electrophoretic and gel filtration properties, amelogenin is a multi-component system; however, immunologically, amelogenin acts as a single antigen.
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    Calcified tissue international 4 (1969), S. 231-244 
    ISSN: 1432-0827
    Keywords: Calcification ; Pyrophosphate ; Inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les propriétés d'induction de calcification des liquides biologiques peuvent être mesurées, in vitro et in vivo, par leur possibilité de redurcir des blocs d'émail décalcifié. Cette propriété est exprimée par les concentrations de calcium (et de phosphate) de solutions synthétiques inductrices de calcification, de concentrations et d'activité connues. Un plasma humain typique a une activité inductrice correspondant à celle d'une solution contenant du calcium, 0,70 mM, Ca/P, 1,67 et fluorure, 0,05 mM. L'activité relativement peu élevée des sérums et des plasmas s'explique par la présence d'inhibiteurs ioniques. L'ion phosphate est l'un d'eux, mais ne peut rendre compte de l'inhibition totale. Des anions et des cations sont responsables de l'inhibition, avec un rôle majeur pour les cations. Les ions suivants, en concentration physiologique, jouent un rôle inhibiteur: P7O 7 4− , HCO 3 − , SiO 4 2− , CrO 4 2− , Mg2+, Zn2+. Un mélange de ces ions provoque une inhibition totale identique à celle du plasma.
    Abstract: Zusammenfassung Der Einfluß biologischer Flüssigkeiten auf den Verkalkungsvorgang kann in vitro und in vivo anhand ihrer Fähigkeit, enthärtete Blöcke von Zahnschmelz wieder zu härten, gemessen werden. Diese Aktivität wird ausgedrückt als Konzentration des Calciums (und Phosphates) synthetischer calcifizierender Lösungen mit bekannter Konzentration und Aktivität. Die Aktivität eines charakteristischen menschlichen Plasmas entsprach derjenigen einer Lösung folgender Zusammensetzung: Calcium 0,70 mM; Ca/P=1,67 und Fluorid 0,05 mM. Die relativ niedrige Aktivität von Serum und Plasma ist bedingt durch das Vorhandensein einer Anzahl ionischer Inhibitoren. Das Pyrophosphation ist ein solcher; er kann aber nicht für die gesamte Inhibition verantwortlich gemacht werden. Sowohl anionische als auch kationische Inhibitoren sind vorhanden, wobei die Kationen den Hauptanteil ausmachen. Folgende Ionen erwiesen sich in einer physiologischen Konzentration als Inhibitoren synthetischer Systeme: P7O 7 3− , HCO 3 − , SiO 4 1− , CrO 4 2− , Mg2+, Zn2+. Zusammengenommen verursachten diese Ionen eine Gesamtinhibition ähnlich derjenigen des Plasmas.
    Notes: Abstract The calcifying activities of biological fluids can be measured,in vitro andin vivo, by their ability to reharden softened blocks of tooth enamel. The activity is expressed in terms of the calcium (and phosphate) concentrations of synthetic calcifying solutions of known concentration and activity. A typical human plasma had an activity corresponding to that of a solution of the following concentration: calcium, 0.70 mM; Ca/P, 1.67 and fluoride, 0.05 mM. The relatively low activity of serums and plasmas was shown to arise from the presence of a number of ionic inhibitors. Pyrophosphate ion is one such inhibitor but cannot account for the major inhibition. Both anionic and cationic inhibitors were shown to be present, with the cations respresenting the major portion. The following ions at their reported physiological concentration were shown to be inhibitors in synthetic systems: P7O 7 4− , HCO 3 − , SiO 4 2− , CrO 4 2− , Mg2+, Zn2+. In combination, these ions caused a total inhibition similar to those for plasmas.
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    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.
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    Calcified tissue international 3 (1969), S. 151-162 
    ISSN: 1432-0827
    Keywords: Calcification ; Physiologic ; Phosphonic Acids ; Phosphates ; Crystallization ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé On a étudié la formation de l'hydroxyapatite de calcium cristallin à partir de solutions d'ions de calcium et de phosphate et l'inhibition de la croissance de cristaux de l'hydroxyapatite de calcium au moyen de polyphosphonates et de polyphosphates. Les polyphosphonates, éthane hydroxy-1-diphosphonate-1,1 de disodium et dichlorométhanediphosphonate de disodium, sont inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium. Les polyphosphates sont aussi inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium tant que le niveau exigé de polyphosphate intact est présent dans le système. Cependant, à cause de leur instabilité hydrolytique, qui est soulignée par une température élevée, valeur de pH basse, et certaines enzymes, la concentration du polyphosphate diminue avec le tempsin vitro, et son activité comme inhibiteur est perdue. Au contraire aux polyphosphates, les polyphosphonates sont hydrolytiquement stables. Les polyphosphonates sont chimiosorbés sur la surface des microcristallites de l'hydroxyapatite de calcium, ainsi empêchant l'occurrence d'autre croissance de cristaux semblable à l'action d'autres poisons connus de croissance de cristaux. On propose l'extension de cette action sur la formation de l'apatite et cette stabilité des polyphosphonates aux applications médicales et dentaires concernant le metabolisme pathologique de calcium et de phosphate.
    Abstract: Zusammenfassung Die Bildung des kristallinen Calciumhydroxyapatit aus Lösungen, welche Calcium- und Phosphationen enthalten, und die Hemmung der Bildung von kristallinen Calciumhydroxyapatit durch Polyphosphonate und Polyphosphate wurden untersucht. Polyphosphonate, Dinatriumäthan-1-hydroxyl-1,1-diphosphonat und Dinatriumdichloromethandiphosphonate verhindern das Kristallwachstum des Calciumhydroxyapatits. Die Polyphosphate verhindern ebenfalls das Kristallwachstum des Calciumhydroxyapatits, solange die notwendige Konzentration des nicht hydrolysierten Polyphosphats vorhanden ist. Wegen ihrer hydrolytischen Unbeständigkeit, die durch hohe Temperatur, niedrige pH und bestimmte Enzyme erhöht wird, vermindert sich jedoch die Konzentration des Polyphosphats allmählichin vitro, und ihre Hemmungsaktivität geht verloren. Im Gegensatz zu den Polyphosphaten sind die Polyphosphonate hydrolytisch beständig. Die Polyphosphonate werden an der Oberfläche der Mikrokristallite des Calciumhydroxyapatits chemisorbiert und verhindern, wie andere bekannte Kristallwachstumsgifte, auf diese Weise weiteres Kristallwachstum. Die Beständigkeit der Polyphosphonate und ihre Chemisorption an dem Apatit empfehlen ihren Gebrauch in der ärztlichen und zahnärztlichen Praxis, soweit sie den pathologischen Calcium- und Phosphatstoffwechsel betreffen.
    Notes: Abstract The formation of crystalline calcium hydroxyapatite from solutions of calcium and phosphate ions and the inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates have been studied. The polyphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate and disodium dichloromethane diphosphonate, are effective inhibitors of calcium hydroxyapatite crystal growth. The polyphosphates are also effective inhibitors of calcium hydroxyapatite crystal growth as long as the required level of intact polyphosphate is present in the system. However, because of their hydrolytic instability, which is enhanced by high temperature, low pH, and certain enzymes, the concentration of the polyphosphate decreases with timein vitro, and its activity as an inhibitor is lost. In contrast to the polyphosphates, the polyphosphonates are hydrolytically stable. The polyphosphonates are chemisorbed on the surface of the microcrystallites of calcium hydroxyapatite and, in the manner of other known crystal growth poisons, thus prevent further crystal growth. The stability of the polyphosphonates and their chemisorption on apatite suggest their use in medical and dental applications involving pathological calcium and phosphate metabolism.
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    Calcified tissue international 3 (1969), S. 266-273 
    ISSN: 1432-0827
    Keywords: Calcification ; Arteries ; Membranes ; Elastic tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Avec la modification d'une méthode de von Kossa nous avons macroscopiquement representé les dessins de calcification de la membrane élastique intérieure, ainsi que les grosses artères du bassin, des artères des extrémités inferieures, des artères du bras, de la rate et des reins. Dans les artères du type élastique, dans les A.a. ilicae communes et internae, se présentaient les dégénérations calcaires de la membrane élastique intérieure sous forme d'incrustations noires arrondies ou polygonales qui ont été formes en groupes. Elles étaient toujours présentes chez des enfants agés de plus de trois mois et chez des aux adultes. Dans les artères musculaires, se montraient les parties calcifiées de la membrane élastique intérieure en forme de «bandes de calcaire» noires et groupes en paires le long des bordures des fissures de la membrane. Dans le cas où existait une calcinose forcée, on pouvait montrer avec cette méthode tout le système de fissures de la mambrane élastique intérieure. Chez tous les morts âgés de 10 à 20 ans, nous avons trouvé des bandes de calcaire dans les artères musculaires des extrémités inferieures. Ces bandes de calcaire ont été constatées aussi dans des personnes plus âgées. Au point de la fusion des bandes de calcaire et des incrustations calcaire polygonales des dépôts calcaires en forme de feuille («feuilles de calcaire») se forment dans la membrane elastique. Les bandes de calcaire et les feuilles de calcaire représentent des points de cristallisation pour des dépôts calcaire granuleux. Ils se forment dans la plupart des cas sur le la côté externe tourné vers la media.
    Abstract: Zusammenfassung Mit einer modifizierten von Kossa-Methode wurden die Verkalkungsmuster der inneren elastischen Membran der großen Beckenarterien, der Arterien der unteren Extremität, der Oberarm-, Milz-und Nierenarterien makroskopisch dargestellt. In den Arterien vom elastischen Typ, i.e. in den Aa. ilicae communes et internae, erschienen die Verkalkungen der inneren elastischen Membran als schwarze rundliche oder polygonale Inkrustationen, die zu Gruppen angeordnet waren. Sie wurden häufig bereits bei Neugeborenen festgestellt. Bei Kindern, die älter waren als 3 Monate und bei Erwachsenen lagen sie stets vor. — In den muskulären Arterien traten die verkalkten Anteile der inneren elastischen Membran makroskopisch als schwarze paarweise angeordnete „Kalkbänder” entlang den Rändern vorgebildeter Membranspalten auf. Bei ausgeprägter Calcinose konnte mit der angewandten Methode das gesamte Spaltensystem der inneren elastischen Membran dargestellt werden. Kalkbänder wurden in den muskulären Arterien der unteren Extremität bei allen 10–20 Jahre alten Verstorbenen vorgefunden und waren auch in den nachfolgenden Altersstufen stets vorhanden. Beim Zusammenfluß von Kalkbändern und polygonalen Kalkinkrustationen entstehen in der inneren elastischen Membran folienartige Kalkablagerungen („Kalkfolien”). Die Kalkbänder und Kalkfolien stellen Kristallisationspunkte für körnige Kalkablagerungen dar, die zumeist an ihrer äußeren, der Media zugekehrten Seite entstehen.
    Notes: Abstract Calcification patterns of the internal elastic membrane of the main pelvic arteries, lower limb arteries, brachial, splenic and renal arteries were demonstrated grossly by a modified von Kossa technique. In the elastic segment in the common and internal iliac arteries, the membrane calcification appeared as groups of roundish or polygonal incrustations. They were found frequently in newborns, and were always present in infants of more than three months, as well as in adults. In the muscular arteries, the calcified parts of the internal elastic membrane appeared grossly as pairs of bands (“calcific bands”) along the edges of the pre-existing gaps in this membrane. When calcification was pronounced, the whole pattern of the membrane gaps could be demonstrated by the method used in this study. Calcific bands were found in the muscular arteries of the lower limbs in all 10–20 year-old subjects, and were always present in the older age groups. The confluence of calcific bands or polygonal membrane incrustations found in the iliac arteries lead to sheet-like membrane calcification. The calcific bands and sheets represent crystallizing points for grain-like calcific deposits, which appear later on the medial surface.
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    Calcified tissue international 4 (1969), S. 136-146 
    ISSN: 1432-0827
    Keywords: Bone ; Calcification ; Osteoblasts ; Osteoclasts ; Poultry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'activité des cellules osseuses et la composition du fémur de pondeuses furent examinées pendant sept jours de déficience calcique (diète contenant 0,13% de calcium) et sept jours de réplétion (diète contenant 3,2% de calcium). Du point de vue histologique, seul l'os cortical donnait des signes nets de résorption et d'activité ostéoclastique. Le nombre d'ostéoclastes dans l'os médullaire différait peu des valuers témoin pendant les périodes de déficience et de réplétion subséquente, sauf pour une augmentation significative au premier jour de déplétion. L'effect histologique le plus important dans l'os médullaire était une augmentation marquée en nombre d'ostéoblastes aux troisième, cinquième, et un peu moins au septième jours de déplétion. Le nombre d'ostéoblastes était en corrélation positive avec la teneur de l'os médullaire en ostéoide et négative avec son degré de calcification. L'activité de l'os médullaire en phosphatase alcaline augmentait avec la longueur de la déficience calcique. Un jour après le retour des pondeuses à une diète contenant 3,2% de calcium, la calcification de l'os médullaire avait augmenté de façon significative, le nombre d'ostéoblastes avait diminué au niveau ou au-dessous du niveau de contrôle et l'activité de la phosphatase alcaline avait baissé considérablement. L'importance de ces résultats est discutée par rapport au controle des populations des cellules dan l'os et au rôle de l'os médullaire.
    Abstract: Zusammenfassung Die Zahl der Knochenzellen und die Zusammensetzung des Femurs von Legehennen wurden während einer siebentägigen Calciumentzugsperiode (Calciumgehalt des Futters 0,13%) und einer siebentägigen Ersatzperiode (Calciumgehalt des Futters 3,2%) untersucht. Histologisch zeigte nur die Cortex eindeutige Knochenresorption und osteoklastische Aktivität. Abgesehen von einer signifikanten Zunahme am 1. Tag des Calciumentzuges, variierte die Zahl der Osteoklasten im Markknochen sowohl während der Entzugs- als auch während der nachfolgenden Ersatzperiode wenig. Die wichtigste histologische Änderung im Markknochen bestand in einer starken Zunahme in der Zahl der Osteoblasten am 3., 5. und etwas weniger am 7. Tag der Entzugsperiode. Die Zahl der Osteoblasten zeigte eine positive Korrelation mit dem Osteoidgehalt des Markknochens und eine negative mit dem Grade seiner Verkalkung. Die Aktivität der alkalischen Phosphatase im Markknochen war desto größer je länger den Hennen die calciumarme Ration verfüttert worden war. Die Wiederverabreichung der Ration, welche 3,2% Calcium enthielt, verursachte innerhalb eines Tages eine signifikante Zunahme in der Verkalkung des Markknochens, ein Absinken der Osteoblastzahl auf die Kontrollwerte oder unter sie und eine drastische Verringerung der alkalischen Phosphataseaktivität. Die Bedeutung dieser Ergebnisse in bezug auf die Kontrolle des Knochenzellenbestandes und auf die Funktion des Markknochens wird diskutiert.
    Notes: Abstract Bone cell activity and the composition of the femur of laying hens were studied during 7 days of calcium depletion on a 0.13% calcium diet and 7 days of calcium repletion on a 3.2% calcium diet. Histologically, only cortical bone showed clear signs of bone resorption and osteoclastic activity during the depletion period. The number of osteoclasts in medullary bone varied little from control values throughout both calcium depletion and repletion, except for a significant increase on the first day of depletion. The major histologicalchange in medullary bone was a marked increase in the number of osteoblasts on the third, fifth and, to a lesser extent, seventh, day of depletion. The number of osteoblasts in medullary bone was positively correlated with its osteoid content and negatively correlated with its degree of calcification. Alkaline phosphatase activity of medullary bone increased with the time the hens had been on the calcium-deficient diet. Returning the hens to the 3.2% calcium ration caused, within one day, a significant increase in medullary bone calcification, a decrease of osteoblast numbers to, or below, control levels, and a drastic reduction in alkaline phosphatase activity of medullary bone. The significance of these findings in relation to the control of bone cell populations and the functions of medullary bone is discussed.
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    Calcified tissue international 4 (1969), S. 260-268 
    ISSN: 1432-0827
    Keywords: Cartilage ; Histochemistry ; Staining ; Protein ; Polysaccharide ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des coupes de cartilage épiphysaire frais de jeunes rats, effectuées à la main, sont colorées à pH=4,5 dans des solutions à 0,01% de divers colorants cationiques, appartenant aux groupes de la thiazine, oxazine, azine, triphénylméthane, acridine, et phthallocyanine. Les granules intracellulaires métachromatiques, mises en évidence antérieurement par le bleu de toluidine, sont également identifiées à l'aide de l'azur A, le bleu de méthylène et le bleu de crésyl. Les granules se colorent moins bien à la thionine, le rouge neutre, la safranine O, le bleu de toluylène et l'acridine orange. Dans les conditions utilisées, la matrice de la zone de réserve et la matrice de la zone hypertrophique inférieure (en voie de calcification) se colorent, alors que les matrices des zones prolifératives et hypertrophiques supérieures ne prennent pas les colorants. La gallocyanine, le violet cristal, la fuchsine basique, l'azocarmin B, le bleu de gallamine et la bleu alcian ne se colorent pas ou donnent des réactions colorées différentes de celles décrites ci-dessus. Il semble que le pK et le poids moléculaire des colorants jouent un rôle important, mais ils ne paraissent pas être les seuls facteurs intervenant dans la coloration des granules. Un changement, lié à la calcification, semble intervenir au niveau du matériel métachromatique (probablement des polysaccharides protéiques), aussi bien dans la matrice que les cellules cartilagineuses épiphysaires.
    Abstract: Zusammenfassung Handpräparierte Schnitte von frischem Epiphysenknorpel junger Ratten wurden bei einem pH von 4,5 in 0,01% igen Lösungen verschiedener kationischer Farbstoffe folgender Klassen gefärbt: Thiazin, Oxazin, Azin, Triphenylmethan, Acridin und Phthalocyanin. Die intracellulären β-und γ-metachromatischen Granula, erstmals mit Toluidinblau im frischen Gewebe nachgewiesen, konnten auch gut mit Azur A, Methylenblau und Brillantkresylblau dargestellt werden. Die Granula konnten ebenfalls, aber weniger gut, mit Thionin, Neutralrot, Safranin D, Toluylenblau und Acridinorange gefärbt werden. Unter diesen Färbungsbedingungen werden die inaktive Matrixzone und die untere hypertrophische (verkalkende) Matrixzone angefärbt, während die proliferative und die obere hypertrophische Matrixzone sich nicht färben. Gallocyanin, Kristallviolett, basisches Fuchsin, Azokarmin B, Gallaminblau und Alzianblau färbten entweder gar nicht, oder gaben ein anderes als das obenbeschriebene Färbemuster. Es wird vorgeschlagen, daß das pK und das Molekulargewicht der Farbstoffe wichtig aber nicht unbedingt die einzigen Faktoren sind, die die Färbung der Granula bestimmen. Die Resultate zeigen, daß eine Veränderung im metachromatischen Material (vermutlich Proteinpolysaccharide) vorliegt, und zwar sowohl in der Matrix als in den Zellen des Epiphysenknorpels; diese Veränderung scheint im Zusammenhang mit der Verkalkung zu stehen.
    Notes: Abstract Hand-cut sections of fresh epiphyseal cartilage from young rats were stained at pH 4.5 in 0.01% solutions of various cationic dyes of the thiazine, oxazine, azine, triphenylmethane, acridine, and phthallocyanin classes. The intracellular β-and γ-metachromatic granules, previously demonstrated in fresh tissues with toluidine blue, were also demonstrated well with azure A, methylene blue, and brilliant cresyl blue. The granules were also demonstrated, but not as well, by thionin, neutral red, safranin O, toluylene blue, and acridine orange. Under the conditions of staining, the reserve zone matrix and the lower hypertrophic (calcifying) zone matrix stained, whereas the proliferative and upper hypertrophic zone matrix did not stain. Gallocyanin, crystal violet, basic fuchsin, azocarmine B, gallamine blue, and alcian blue either did not stain, or gave a different pattern of staining from that described above. It is suggested that the pK and molecular weight of the dyes are important, but not necessarily the only factors in determining the staining of the granules. The results indicate that there is a change in the metachromatic material (presumably proteinpolysaccharide) in both the matrix and cells of epiphyseal cartilage, which appears to be related to calcification.
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    Calcified tissue international 4 (1969), S. 350-358 
    ISSN: 1432-0827
    Keywords: Bone ; Calcitonin ; Resorption ; Species ; Discrimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une méthode quantitativein vitro est utilisée pour étudier l'efficacité relative des préparations de calcitonine, provenant de diverses espèces. La méthode est basée sur le fait que la calcitonine inhibe de façon nette la libération de45Ca de moitiés de calottes craniennes de souris, âgées de 6 jours, ayant été marquées auparavant; cet effect est lié à la suppression de la résorption endogène, qui se déroule, lorsque les os sont explantés et qui se continuein vitro en l'absence de calcitonine. Des différences nettes de l'effect d'inhibition des préparations de calcitonine ont été trouvées, qu'elles proviennent de corps ultimobranchiaux ou de thyroides de mammifères. La calcitonine humaine et la calcitonine porcine, standard A, se comportent de façon identique et sont environ dix fois plus actifs que la calcitonine porcinek standard B, en se basant sur les critéres unitaires utilisés au cours de cette étude chez le rat. Les calcitonines de corps ultimobranchiaux sont plus efficaces à doses faibles, pendant des périodes plus longues, que les préparations thyroidiennes et elles sont au moins dix fois plus efficaces que la calcitonine porcine standard A et cent fois plus actives que la calcitonine porcine standard B. Les explants traités par la calcitonine libère l'isotope dans le milieu d'une manière identique à celle de l'os mort, tant que la calcitonine reste active: pour la calcitonine de saumon, on observe pendant 20 heures un échange d'isotope entre l'os vivant, traité avec ce produit et le calcium du milieu, ainsi que cela se produit pour des fragments d'os congelé. Ces résultats sont utiles pour des études quantitatives, devant déterminer le mode d'action d'autres produits influençant la résorption et l'apposition osseuse. L'adjonction de calcitonine permet, en effet, de mesurer l'échange d'isotope libéré de l'os, ainsi traité à tous les stades, sans tuer les tissus ou sans avoir recours à des inhibiteurs spécifiques du métabolisme.
    Abstract: Zusammenfassung Ein quantitativerin vitro-Versuch wurde angewandt, um die relative Wirksamkeit von Calcitonin-Präparaten aus verschiedenen Spezies zu untersuchen. Der Versuch beruht auf der Feststellung, daß Calcitonin einen ausgeprägten Hemmeffekt auf die Freisetzung von45Ca aus markierten Calvarien-Hälften von 6tägigen Mäusen hat. Dieser Effekt kommt wegen der Unterdrückung der endogenen Resorption zustande, die im Moment der Knochenexplantation im Gange ist, undin vitrobei Abwesenheit von Calcitonin weiter fortschreitet. Auffallende Unterschiede des Hemmeffektes konnten bei Calcitonin-Präparaten sowohl von Ultimobranchialkörpern als auch von Säuger-Thyreoideae festgestellt werden. Menschliches Calcitonin sowie Standard A Schweine-Calcitonin verhalten sich gleich und sind ungefähr 10mal wirksamer als Standard B Schweine-Calcitonin, ausgedrückt in Einheiten bezogen auf den Rattenversuch. Die von Ultimobranchialkörpern stammenden Calcitonin-Präparate sind wirksamer in niedrigerer Dosierung und während einer längeren Zeitspanne als die Thyreoidea-Präparate. Sie wirken zudem mindestens 10mal stärker als Standard A Schweine-Calcitonin und 100mal stärker als Standard B Schweine-Calcitonin. Explantate, welche mit Calcitonin behandelt wurden, geben das Isotop auf die gleiche Weise wie totes Knochengewebe in das Medium ab, solange das Calcitonin wirksam ist. Für Calcitonin vom Lachs besteht eine Zeitpsanne von 20 Std, während welcher die lebenden, mit diesem Präparat behandelten Knochen das Isotop mit dem Calcium des Medium austauschen, in gleicher Weise wie durch Einfrieren und Auftauen getöteten Knochens. Diese Methode wird vermutlich sehr nützlich sein für quantitative Untersuchungen über den Aktionsmodus anderer Stoffe, welche Knochenresorption und-wachstum beeinflussen, da der Calcitonin-Zusatz es ermöglicht, die Austauschkomponente des aus dem behandelten Knochen freigesetzten Isotopes jederzeit zu messen, ohne daß dabei Gewebe zerstört oder weniger spezifische Inhibitoren des Metabolismus herangezogen werden müssen.
    Notes: Abstract Anin vitro method has been used to investigate the relative effectiveness of calcitonin preparations from different species. It is based on the finding that calcitonin has a marked inhibitory effect on the release of45Ca from prelabelled half-calvariae from 6-day-old mice; this effect is due to the suppression of the endogeneous resorption that is in progress when the bones are explanted, and which continuesin vitro in the absence of calcitonin. Striking differences have been found in the inhibitory effect of calcitonin preparations from either ultimobranchial bodies or from mammalian thyroids. Human calcitonin and porcine standard A calcitonin behave similarly and are about ten times more potent than porcine standard B calcitonin in terms of units based on the rat assay. The calcitonins of ultimobranchial origin are more effective at lower doses for a longer period of time than the thyroid preparations, and are at least ten times more potent than porcine standard A calcitonin or 100 times more potent than porcine standard B. Explants treated with calcitonin release isotope into the medium in a similar manner to that of dead bones, as long as the calcitonin remains effective; for salmon calcitonin there is a twenty-hour period in which the release of isotope from living bones treated with this preparation exchange isotope with the calcium in the medium like frozen-thawed bone. This finding should be very useful in quantitative studies on the mode of action of other compounds that influence bone resorption and accretion, since the addition of calcitonin will enable the exchange component of the isotope released from treated bones, to be measured at any stage without killing the tissue or resorting to less specific inhibitors of metabolism.
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    Cell & tissue research 101 (1969), S. 232-240 
    ISSN: 1432-0878
    Keywords: Enamel ; milk teeth ; tooth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of secreting ameloblasts of deciduous teeth from a human foetus (crown-rump length 195 mm) was investigated. The ameloblasts demonstrate a formation of granules in a juxtanuclear Golgi complex. In the Tomes' process the granules are released either through the lateral plasma membrane into the intercellular space between the Tomes' processes or directly through the apical plasma membrane into the enamel. The human ameloblasts differ from non-human ameloblasts in having a non-oriented vesicular granular endoplasmic reticulum. Further, the majority of mitochondria are situated in the apical part of the ameloblast adjacent to the Tomes' process.
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    Calcified tissue international 2 (1968), S. 1-19 
    ISSN: 1432-0827
    Keywords: Collagen ; Hydroxyapatite ; Keratin ; Enamel ; Calcification
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    Calcified tissue international 2 (1968), S. 60-66 
    ISSN: 1432-0827
    Keywords: Fluorides ; Topical/Pharmacodynamics ; Penicillin/Pharmacodynamics ; Calcification ; Physiologic/Drug Effects ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'objet de ce travail était de comparer le phénomène de la maturation postéruptive dans les molaires des rats ordinaires et sans germes à qui on a donné à manger un régime «non-cariogène». On a étudié les effets de l'application topique du fluorure et de la nourriture de la penicilline sur la maturation. Les molaires des rats ordinaires (nourris d'un régime «chow» — aliment mixte pour les animaux préparé d'habitude sous la forme d'une farine ou en boulettes) traités topiquement avec une solution à 1% de NaF et les molaires des rats ordinaires nourris d'un régime «chow» complété avec la penicilline à 1% ont montré un degré de maturation significativement plus grand que les molaires des rats de la même portée nourris de «chow» et traités avec de l'eau. De l'autre côté, les molaires des rats sans germes traités topiquement avec une solution à 1% de NaF n'ont montré aucune différence significative dans le degré de maturation des molaires de rats de contrôle semblables traités topiqument avec l'eau. Ces résultats sont en accord avec l'hypothèse que dans un milieu normal le procédé de minéralisation (maturation) est opposé par un procédé de déminéralisation. Le procédé de déminéralisation est un résultat de la production d'acide par des bactéries qui métabolisent les aliments encastrés dans les «sulci» des molaires. On propose que dans les animaux ordinaires le fluorure et la penicilline peuvent influencer la maturation en empêchant le procédé de déminéralisation. Dans les animaux sans germes le procédé de déminéralisation est absent parce que la microflore orale est absente.
    Abstract: Zusammenfassung Der Zweck dieser Arbeit war ein Vergleich des nach dem Durchbruch auftretenden Reifungsphänomens der Backenzähne von gewöhnlich und von keimfrei gehaltenen Ratten, die mit einer nicht-cariogenen Diät ernährt wurden. Es wurden die Auswirkungen von topisch angewendetem Fluorid, verbunden mit Penicillin-Fütterung auf die Reifung untersucht. Die Backenzähne der gewöhnlich gehaltenen Ratten (mit “Chow”-Diät ernährt), die mit einer 1%igen Na-Fluoridlösung topisch behandelt wurden, und solchen deren “Chow”-Diät zu 1% mit Penicillin versetzt wurde, zeigten einen erheblich größeren Reifungsgrad als die Backenzähne von Tieren des gleichen Wurfes, die nur mit der “Chow”-Diät und Wasser ernährt wurden. Diese Resultate stimmen mit der Hypothese überein, daß in einer normalen Umgebung dem Mineralisationsprozeß (Reifung) ein Demineralisationsprozeß entgegenwirkt. Der Demineralisationsprozeß ist durch eine Säureproduktion von Bakterien bedingt, welche die in die Zahnfurchen eingepreßten Nahrungsbestandteile metabolisieren. Es wird die Annahme vorgeschlagen, daß Fluoride und Penicillin bei den gewöhnlich gehaltenen Tieren die Reifung durch eine Inhibition des Demineralisationsprozesses beeinflussen. Bei keimfrei gehaltenen Tieren findet dagegen kein Demineralisationsprozeß statt, da die orale Mikroflora fehlt.
    Notes: Abstract The purpose of this work was to compare the phenomenon of post-eruptive maturation in molars of conventional and germfree rats fed non-cariogenic diets. The effects of topical application of fluoride and feeding penicillin on maturation were studied. The molars of conventional rats (fed a chow diet) treated topically with a 1% NaF solution and the molars of conventional rats fed a chow diet supplemented with 1% penicillin showed a significantly greater degree of maturation than did the molars of littermate rats fed chow and treated with water. On the other hand, the molars of germfree rats treated topically with a 1% NaF solution showed no significant difference in degree of maturation from the molars of similar control rats topically treated with water. These data are consistent with an hypothesis that in a normal environment the mineralization (maturation) process is opposed by a demineralization process. The demineralization process is a result of production of acid by bacteria metabolizing the diet impacted in the sulci of molars. It is proposed that in conventional animals fluoride and penicillin may influence maturation by inhibiting the demineralization process. In the germfree animals the demineralization process is absent because the oral microflora is absent.
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  • 67
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    Calcified tissue international 2 (1968), S. 361-369 
    ISSN: 1432-0827
    Keywords: Calcification ; Hydroxyapatite ; Keratin ; Hair ; Electron diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Certaines régions du cortex des fibres de kératine contiennent une proportion relativement élevée de matériel non kératinisé. L'orientation microfibrillaire dans ces régions est biaxiale et on y trouve, en outre, des zones de matériel amorphe. Les sels calciques, et en particulier l'hydroxyleapatite, sont étudiés par diffraction électronique qui permet de les localiser et de les identifier. En outre, cette technique permet de déterminer la fréquence de cellules nonkératinisées dans la partie interne du cortex et de les comparer avec les propriétés histochimiques de cette région. Une comparison est effectuée entre la calcification de la kératine et celle intéressant le collagène et l'élastine.
    Abstract: Zusammenfassung Es wird gezeigt, daß Bereiche im Cortex von gewissen Keratinfasern einen relativ hohen Anteil an nichtkeratinösem Material enthalten. Ferner konnte nachgewiesen werden, daß die Orientierung der Mikrofibrillen in diesen Bereichen biaxialer Art ist, und daß Bezirke von amorphem Material vorhanden sind. Die Calciumsalze und insbesondere das Hydroxyapatit konnten mit Hilfe der Elektronendiffraktion lokalisiert und identifiziert werden. Diese Methode hat sich auch als wertvoll erwiesen, um die Wechselbeziehung zwischen dem Vorkommen von einigen nichtkeratinisierten Zellen im Cortexinnern und den histochemischen Eigenschaften dieser Regionen zu zeigen. Ein Vergleich wird gemacht zwischen der Umgebung der Verkalkungsstellen im Keratin mit derjenigen im Kollagen und im Elastin.
    Notes: Abstract Regions in the cortex of some keratin fibres are shown to contain a relatively high proportion of non-keratinous material. The microfibrillar orientation in these regions is shown to be biaxial in nature and, in addition, areas of amorphous material are reported. Calcium salts, in particular hydroxyapatite, have been located and identified using electron diffraction, which has also proved valuable in correlating the incidence of some non-keratinised cells in the inner part of the cortex with the histochemical properties of this region. A comparison is made between the environment of the sites of calcification in keratin with those in collagen and elastin.
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  • 68
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    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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  • 69
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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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  • 70
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    Calcified tissue international 2 (1968), S. 353-360 
    ISSN: 1432-0827
    Keywords: Enamel ; Dental ; Protein ; Foetal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé De la matrice d'émail de bœuf déminéralisé est soumise à l'électrophorèse à gel de polyacrylamide, à pH acide. Une composition protéique beaucoup plus complexe que celle décrite jusqu'à présent est mise en évidence. Elle est constituée par 6 composés principaux et 12 composés mineurs. La chromatographie par filtration sur gel Sephadex G. 50, à pH 3.0 et sous force ionique faible, donne une séparation partielle de ces composants, qui concorde avec le fractionnement obtenu par différences de poids moléculaire. L'électrophorèse à polyacrylamide de ces fractions, avec et sans 5 M d'urée, montre qu'à pH acide, les composés isolés dans les gels d'acrylamide ne constituent pas des substances labiles. Ces résultats sont envisagés en fonction des théories actuelles concernant la composition matricielle et son rôle possible au cours de la calcification de l'émail.
    Abstract: Zusammenfassung Die fetale Zahnschmelzmatrix von Rindern wurde demineralisiert und einer Polyacrylamid-Gel „Dise”-Elektrophorese bei saurem pH unterworfen. Diese Technik zeigte eine Proteinzusammensetzung, die komplexer ist als bisher beschrieben wurde, nämlich mit mindestens 6 Haupt- und 12 Nebenkomponenten. Sephadex G 50 Gel-Filtrations-Chromatographie bei einem pH von 3.0 und schwacher Ionenstärke ergab eine teilweise Trennung dieser Komponenten, in Übereinstimmung mit einer Fraktionierung, welche sich auf Unterschiede im Molekulargewicht stützt. Eine Polyacrylamid- Elektrophorese dieser Säulenfraktionen sowohl mit als auch ohne 5 M Harnstoff zeigte, daß bei saurem pH die Acrylamid-Gel sichtbaren Komponenten nicht als labile Aggregate vorhanden sind. Diese Resultate werden im Zusammenhang mit den aktuellen Begriffen über die Zusammensetzung der Matrix und ihrer möglichen Rolle bei der Verkalkung des Zahnschmelzes besprochen.
    Notes: Abstract Demineralised bovine foetal enamel matrix was subjected to polyacrylamide gel “disc” electrophoresis at acid pH. This technique revealed a protein composition more complex than hitherto described with a minimum of six principal and twelve minor components. Sephadex G. 50 gel filtration chromatography at pH 3.0 and low ionic strength produced a partial separation of these components in accord with a fractionation based on molecular weight differences. Polyacrylamide electrophoresis of these column fractions both in the presence and absence of 5 M urea, showed that at acid pH the components seen in the acrylamide gels were not present as labile aggregates. These results are discussed in relation to current concepts of the matrix composition and its possible role in the calcification of enamel.
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