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The effect of some inhibitors on the nucleation and crystal growth of apatite (1969)

Bachra, B. N. ; Fischer, H. R. A.

Springer

Calcified tissue international 3 (1969), S. 348-357

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ISSN: 1432-0827

Keywords: Inhibitors ; Nucleation ; Apatite ; Collagen

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Description / Table of Contents: Résumé Des ions de Mg, Sr et F sont inhibitoires pour la formation de l'apatite quand on les ajoute à un tampon de calcification, séparément ou en combinaisons. La précipitation de l'apatite causée par des cristaux d'apatite est moins sensible à l'action inhibitrice que la nucléation spontanée et que la précipitation catalysée par la collagène d'os de mouton. La précipitation spontanée ou catalysée sont approximativement aussi sensibles. L'inhibition par des combinaisons de Mg avec des ions de Sr ou de F est additive. Ces résultats montrent que ces inhibiteurs ont acucune action spécifique sur la catalysation par la collagène de l'os de mouton qui soit différente de celle sur la nucléation de l'apatite en soi.

Abstract: Zusammenfassung Mg, Sr und F Ionen hemmten die Fällung von Apatit wenn sie zu einem Calciumphosphatpuffer einzeln oder zusammen hinzugefügt wurden. Die Fällung von Apatit durch Apatitkeime war weniger empfindlich hinsichtlich der Hemmung als die spontane Nucleation und als die Fällung von Apatit, welche von Schafsknochenkollagen katalysiert werden kann. Die spontane und katalysierte Fällung sind ungefähr gleich empfindlich. Die Hemmung von Mg in Kombination mit Sr oder F Ionen war additiv. Diese Resultate weisen darauf hin, daß keine spezifischen Effekte bei der Katalyse von Knochenkollagen vorliegen, welche von den Effekten bei der Nucleation von Apatit an sich verschieden sind.

Notes: Abstract Mg, Sr and F ions acted as inhibitors of apatite formation when added to a calcification buffer separately or in combinations. The precipitation of apatite under the influence of apatite seeds was less susceptible to inhibition than were spontaneous nucleation and apatite formation catalyzed by sheep bone collagen, while the latter two were about equally susceptible. Combinations of Mg with Sr or F ions showed additive effects. These results suggest that no specific effects of these inhibitors occurred on the catalytic action of the bone collagen different from their effects on the nucleation of apatite as such.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02058677

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2

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A macromolecular inhibitor of in vitro calcification of tendon matrix (1978)

Quittner, C. ; Wadkins, C. L.

Springer

Calcified tissue international 25 (1978), S. 161-168

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ISSN: 1432-0827

Keywords: Tendon ; Calcification ; Collagen ; Inhibitors ; Proteoglycans

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Summary Bovine and human tendon tissue do not induce calcification in vitro. However, extraction of those tissues with 3% Na2HPO4 converts them to calcifiable matrices. The supernatant fraction derived from the extraction contains a nondialyzable, perchloric acid soluble component that inhibits calcification of the extracted matrix. This inhibitory substance is characterized by a molecular weight in the range of 85,000–100,000. Exposure to pronase or hyaluronidase did not alter the inhibitory potency but did render the inhibitor dialyzable. Commercial sources of hyaluronic acid, chondroitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, heparin and lysozyme did not inhibit calcification of the extracted matrix. Phosvitin, a phosphoglycoprotein is a potent inhibitor. Although phosvitin and the tendon extract also inhibit calcification of previously calcified matrix, they have no detectable effect on the rate of decalcification. We conclude that the mechanism of inhibition is characterized by a degree of specificity and that phosvitin and a macromolecular component of tendon tissue blocks conversion of an intermediate matrix-bound CaP complex to crystalline apatite. It seems reasonable that the tendon inhibitor could function in situ and possibly in vivo to control calcification of tendon tissue.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02010764

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3

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A preliminary characterization of human cementum collagen (1977)

Christner, P. ; Robinson, P. ; Clark, C. C.

Springer

Calcified tissue international 23 (1977), S. 147-150

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ISSN: 1432-0827

Keywords: Collagen ; Cementum ; Human cementum

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Summary Human teeth were used to obtain cementum. Collagen could not be significantly solubilized from the cementum by salt and acetic acid extraction or by pepsin digestion. CNBr digestion (86%) of cementum and subsequent carboxymethyl cellulose chromatography suggests that human cementum consists of type I collagen only as identified by amino acid and hexose analyses.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02012780

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4

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Rabbit cranial sutures in vitro: A new experimental model for studying the response of fibrous joints to mechanical stress (1979)

Meikle, Murray C. ; Reynolds, John J. ; Sellers, Anthony ; [et al.]

Springer

Calcified tissue international 28 (1979), S. 137-144

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ISSN: 1432-0827

Keywords: Cranial sutures ; Organ culture ; Tensile mechanical stress ; Protein ; Collagen

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Summary An organ culture system has been developed whereby mechanical stress can be applied to cranial sutures under controlled experimental conditions. The application of a continuous tensile mechanical stress (30 g) to cranial sutures from newborn rabbits (1–2 days) was accompanied by a significant increase in the incorporation of3H-leucine and3H-proline into suture protein. The specific activities of3H-hydroxyproline indicated that mechanical stress produced a two-fold increase in the incorporation of3H-proline into collagen. However, the proportion of the total radioactivity recoverable in collagen (45.63±2.33% for nonstressed; 40.58±2.17% for stressed sutures) was not significantly different. These data suggest that the increase in collagen synthesis occurs as part of a general stimulation of protein synthesis, and do not support the view that mechanical stress is the principal mechanism regulating the turnover of collagen in fibrous joints. These initial studies demonstrate that an in vitro experimental model has considerable potential for investigating the morphological and metabolic response of fibrous joints to mechanical deformation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02441232

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5

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On the solid state of bone (1979)

Behari, J. ; Rai, D. V. ; Jha, R.

Springer

Calcified tissue international 28 (1979), S. 33-36

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ISSN: 1432-0827

Keywords: Infrared, visible light ; Bone ; Collagen ; Apatite

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract Photovoltaic effect (infrared and visible light) is observed in bone and its two major components, collagen and apatite, at room temperature. A dimunition in the magnitude of photovoltage is observed after exposure to ultraviolet light in all the cases. The drift mobility of the charge carriers is obtained by measuring I versus V relationships in sandwich samples and relating them to the permitivity of the medium. Lifetime of the injected carriers is measured in the usual way. The data are consistent with the hypothesis that the effects are due to protonic conduction phenomena.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02441215

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6

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Relationship between iron, calcium and phosphate during experimental cutaneous calcinosis (1969)

Gabbiani, G. ; Badonnel, M. C. ; Baud, C. A.

Springer

Calcified tissue international 4 (1969), S. 224-230

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ISSN: 1432-0827

Keywords: Calcinosis ; Calcium ; Iron ; Phosphate ; Collagen

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Description / Table of Contents: Résumé La calcification de la peau (calciphylaxie) provoquée par l'administration sous-cutanée de chlorure de fer chez des rats sensibilisés par le dihydrotachystérol (DHT) est précédée par une déposition sélective de fer (décelable à la microscopie électronique) à la surface des fibres collagènes. Les analyses à la microsonde prouvent que les taux de calcium et de phosphore sont augmentés à l'endroit de l'injection du chlorure de fer même sans l'administration préalable de DHT; cependant, l'apatite ne se forme que chez les animaux prétraités par le DHT. La quantité et le degré de cristallinité de la matière inorganique sont presque identiques au sixième et au trentième jour de l'expérience.

Abstract: Zusammenfassung Durch elektronenmikroskopische Untersuchungen wurde festgestellt, daß die durch subcutane Verabreichung von Eisenchlorid bei Dihydrotachysterin-sensibilisierten Ratten herbeigeführte Hautverkalkung durch eine selektive Eisenablagerung auf der Oberfläche der Kollagenfibrillen eingeleitet wird. Die Röntgenmikroanalyse zeigt an, daß die lokale Calciumund Phosphorkonzentration bereits nach Eiseninjektion allein ansteigt, während Apatitbildung nur in den mit DHT vorbehandelten Tieren erfolgt. Ausmaß und Menge der Kristallisation sind am 6. und 30. Tage nach Versuchsbeginn fast gleich.

Notes: Abstract Calcification of the skin (calciphylaxis) induced by the subcutaneous administration of iron chloride to dihydrotachysterol (DHT)-sensitized rats is preceded by the selective deposition of iron (visible with electron microscopic techniques) on the surface of collagen fibrils. Electron probe X-ray microanalysis indicates that the injectionof iron alone suffices to increase local concentrations of calcium and phosphorus; however, apatite formation occurs only in animals pretreated with DHT. The amount and degree of crystallinity of the inorganic material is very similar on the sixth and thirtieth day after the beginning of the experiment.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02279125

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7

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The effect of electric current on rat tail tendon collagen in solution (1969)

Marino, Andrew A. ; Becker, Robert O.

Springer

Calcified tissue international 4 (1969), S. 330-338

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ISSN: 1432-0827

Keywords: Collagen ; Electric current ; Electrolysis ; Precipitation ; Bone

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Description / Table of Contents: Résumé L'effet du courant électrique sur la collagène soluble, en solution dans l'acide acétique dilué, a été étudié pour des voltages, variant de O à 25 volts. Au-dessus de 2,6 volts, la vormation des bandes collagéniques (définies dans ce travail) parait inversement proportionelle, dans le temps, au voltage appliqué. La formation des bandes parait liée au processus d'électrolyse. Les auteurs démontrent que les pH élevés se situent au niveau de la cathode et qu'ils sont suffisants pour induire une précipitation du collagène. Les résultats antérieurs, publiés dans la littérature, décrivant l'action de courant électrique implanté, sont interpretés en fonction du mécanisme étudié au cours de ce travail.

Abstract: Zusammenfassung Die Wirkung eines elektrischen Stromes auf verdünnte essigsaure Lösungen von löslichem Kollagen wurde bei Spannungen zwischen O und 25 Volt untersucht. Über 2,6 Volt wurde die Bildung von Kollagenbanden (in der Arbeit näher beschrieben) beobachtet, und zwar nach Zeiten, die der angewandten Spannung entgegengesetzt proportional verliefen. Die Bandenbildung wird dem Elektrolyseprozeß zugeschrieben. Wir konnten zeigen, daß sich die hohen pH-Werte rund um die Kathode entwickelten und daß diese genügen, um die Kollagenfällung zu veranlassen. Die Natur dieses Vorganges ist solcher Art, daß erin vivo als Antwort auf durch Stress verursachte Biopotentiale nicht vorkommen kann. Der hier beschriebene Mechanismus erlaubt es, Literaturangaben über den Effekt von implantierten Spannungsquellen zu interpretieren.

Notes: Abstract The effect of electric current on dilute acetic acid solutions of soluble collagen has been studied for impressed voltages of from 0 to 25 volts. Above 2.6 volts the formation of collagen bands (herein defined) were observed at times inversely proportional to the applied voltage. Band formation is attributed to the process of electrolysis. It has been shown that the high pH values are generated in the area of the cathode, and that they are sufficient to induce collagen to precipitate. The nature of the process is such that it cannot occurin vivo as a response to stress induced biopotentials. Reports in the literature describing the effect of implanted voltage sources are interpreted in terms of the mechanism described here.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02279135

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8

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On the state of anionic groups of demineralized matrices of bone and dentine (1977)

Li, Shu-Tung ; Katz, Elton P.

Springer

Calcified tissue international 22 (1977), S. 275-284

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ISSN: 1432-0827

Keywords: Bone ; Calcium ; Collagen ; Dentine ; Phosphoprotein

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract Calcium-binding and biochemical studies have been applied to characterize the state of the carboxylate and protein-bound phosphate groups in the EDTA-demineralized matrices of rat bone and dentine. The organic phosphate and carboxylate content of demineralized bone is virtually identical to that of purified steer skin collagen whereas demineralized dentine has a significantly higher phosphate and carboxylate content, presumably due to the presence of an acidic non-collagenous phosphoprotein. Two classes of calcium-binding sites can be detected in demineralized bone, demineralized dentine, and purified, reconstituted collagen. The number of strong calcium-binding sites correlates with the number of protein-bound phosphate groups. Depending on the preparative procedure, seven to nine such sites (per collagen molecule) are present in dentine, and one to two in the purified reconstituted collagen and in bone. The binding constant for the dentinal sites (1.1×104 M−1), however, is 20 times greater than that for bone or reconstituted collagen fibrils from skin. We tentatively conclude that the strong calcium-binding site in bone and reconstituted collagen is of the form protein-PO 4 − Ca++ whereas in dentine it is of the form the weak binding sites in bone and dentine are of the form protein-COO-Ca++; and that approximately 160 of the 217 carboxylate groups of the collagen molecules of dentine or bone are present as electrostatic linkages of the form protein-COO−+H3N-protein.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02010366

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9

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Effects of fluoride on in vitro calcification of tendon matrix (1978)

Wadkins, C. L. ; Luben, R. A.

Springer

Calcified tissue international 26 (1978), S. 51-59

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ISSN: 1432-0827

Keywords: Collagen ; Calcification ; Fluoroapatite ; Nucleation ; Inhibitors

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Summary Ca2+ and Pi uptake induced in vitro by a collagenous matrix derived from bovine tendon is inhibited by 1×10−6 to 2×10−5 M NaF and stimulated by 2×10−5 to 2×10−3 M NaF. Fluoride uptake occurs only over the latter concentrtion range. The uptake of Ca2+, Pi, and F−1 progresses toward a limiting extent at which the molar Ca/P and Ca/F values are 1.6 to 1.7 and 4.5 to 5.7, respectively. Although the matrix-bound mineral, previously formed in the absence of NaF, readily undergoes dissolution when exposed to a Ca2+- and P-free medium of pH〈7.4, the bound mineral phase formed in the presence of NaF does not. We conclude that fluoroapatite is the primary matrix-bound mineral. The uptake of fluoride, Ca2+. and Pi by both uncalcified and previously calcified matrices is inhibited by methylenediphosphonate and by phosphonoacetate as is calcification in the absence of NaF. Kinetic studies indicate that formation of a CaP complex precedes the uptake of F−1 and suggest that F−1 and OH−1 compete for interation with the CaP complex during the calcification process. We concluded that fluoroapatite formation induced by the collagenous matrix occurs by a multistep pathway comparable to that proposed previously for hydroxyapatite formation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02013234

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10

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A model for the distribution of HAP crystallites in bone—an hypothesis (1979)

Lees, Sidney

Springer

Calcified tissue international 27 (1979), S. 53-56

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ISSN: 1432-0827

Keywords: Bone mineral model ; Crystallites ; Collagen ; TEM

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Summary Previous study of the velocity of sound in hard tissues led to the hypothesis that collagen is stiffened because the intermolecular links between collagen molecules are embedded in mineral by the mineralizing process. Recently published available high-resolution electron microscope studies of biological apatitic crystals frequently show periodic lattice images of the crystal basal plane. Some of these images from bone and dentin display a sequence of etch pits strung linearly along the midline indicating a chain of screw dislocations. These are interpreted to be the loci of the embedded connecting links required by the collagen stiffening hypothesis. The particular crystallites seen in the micrographs probably are from the interfibril region. Most important, the periodic lattice images show the axes of the links must be parallel to the c-axis of the crystallite. The location of the crystallites and their orientation in situ indicate that the c-axis of the crystallites must be perpendicular to the collagen axis. X-ray diffraction studies available in the literature for a long time indicate the c-axis of HAP crystallites are parallel to the collagen molecular axes. A model of the crystallite distribution is presented which reconciles the two types of crystallite orientation. It is assumed there is only one physical mineralization process for all apatitic crystallites. Additional data from several sources, particularly the distribution of mineral between intra- and interfibril spaces deduced by Katz and Li, are used to develop a first-order model of mineral in bone. Hole filling crystallites between ends of colinear collagen molecules have their c-axes parallel to the molecular axis. The other crystallites must have their c-axes perpendicular to the collagen molecular axis.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02441161

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