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At least 73 records · Page 4Linked to original sources

PubMed1977

Effect of collagen crosslinking on the rate of resorption of implanted collagen tubing in rabbits.

Collagen tubes were tanned with glutaraldehyde for different periods of time. Some were oxidized with periodate and sterilized with either 60Co (1.5 Mrad) or propylene oxide. The tubes were coated with polyfilamentous polyester fabric, filled with x-ray contrast material, and implanted subcutaneously in rats and rabbits. Rate of resorption was ascertained by x-ray procedure of progressive leakage of contrast material. A close relation between tanning time of the collagen fabric-combined prostheses and rate of their resorption in subcutis was found in both rats and rabbits. In rabbits, however, the implants were resorbed at a significantly faster rate than in rats. No effect of oxidation of collagen on the resorption was observed. Collagen tubes tanned for shorter time periods and sterilized with propylene oxide were more resistant to degradation than those sterilized with irradiation. This difference was absent, however, with material tanned for longer times. The mechanism of resorption of implanted collagen tubes was studied by morphological methods. The role of inflammatory cells in resorption is documented. The paper indicates the advantages as well as limits of the x-ray method of studying the resorption rate of biodegradable materials.

Animals↗

PubMed1977

Coordinate control of collagen synthesis and cell growth in chick embryo fibroblasts and the effect of viral transformation on collagen synthesis.

Using collagenase digestion as an assay for collagen in partially synchronized secondary cultures of chick embryo fibroblasts, we find that the rate of collagen synthesis remains at a constant fraction of overall protein synthesis (5%) regardless of the growth rate of the cells even when the rate of protein synthesis is accelerated 5-fold by adding serum and altering the pH of the culture medium. However, in cells oncogenically transformed by Rous sarcoma virus, the relative rate of collagen synthesis was decreased by 50% 24 hours after infection and was 10% of the initial rate after 5 days. This selective decrease in rate of collagen synthesis could be reversed in cells infected with an RSV temperature-sensitive transformation-defective mutant at the non-permissive temperature, indicating that the decrease in the rate of collagen synthesis was not merely the result of viral infection but was a direct consequence of oncogenic transformation.

Animals↗

PubMed1975

The isolation of collagen-associated proteoglycan from bovine nasal cartilage and its preferential interaction with alpha2 chains of type I collagen.

A collagen complex from bovine nasal cartilage was prepared by extraction of the tissue with 3M-MgCl2 solutions, by using two different procedures. When it was compared with calf skin acid-soluble tropocollagen by polyacrylamide-gel electrophoresis, the 3M-MgCl2-soluble cartilage collagen in the complex appeared to be predominantly type I in nature, consisting of both alpha1 and alpha2 chains. The soluble cartilage collagens were digested with purified bacterial collagenase, and the soluble digests were fractionated on Sepharose 4B. Hydroxyproline-free proteoglycan was isolated in the excluded volume of the column eluate, and this was found to be an aggregate which could be dissociated to link proteins and proteoglycan subunit by equilibrium-density-gradient centrifugation in a CsCl-4M-guanidinium chloride gradient. Interaction with calf skin-soluble tropocollagen was studied by CM-cellulose chromatography. The link-protein system did not interact, but proteoglycan from the bottom of the gradient did interact. In addition, when proteoglycan subunit was allowed to interact with collagen, there was a preferential binding to the alpha2 and beta12 components, and this effect was also observed with the proteoglycan material obtained from the collagenase digests of 3M-MgCl2-soluble cartilage collagen complexes. However, specificity for alpha2 and beta12 chains was not exhibited by chondroitin sulphate glycosaminoglycan, and it is therefore concluded that preference for alpha2 and beta12 chains is a function of the intact proteoglycan structure.

Animals↗

PubMed1976

Chemistry of the collagen cross-links. Nature of the cross-links in the polymorphic forms of dermal collagen during development.

Both the type I and type III collagens present in embryonic dermis are stabilized by the intermolecular cross-link, hydroxylysino-5-oxonorleucine, derived from hydroxylysine-aldehyde, although the type I collagen possesses a significant proportion of dehydrohydroxylysinonorleucine. However, concurrent with the change in the proportion of the two types of collagen during postnatal development there is a change-over with both type I and III collagens to the labile cross-link, dehydrohydroxylysinonorleucine, derived from lysine aldehyde. The results indicate that the change in the nature of the cross-link with development is determined primarily by the change in the extent of hydroxylation of the lysine residues in the terminal non-helical regions rather than being due to the change in the type of collagen.

Amino Acids↗

PubMed1975

Collagen development in granulation tissue as compared with collagen of skin and aorta from injured and non-injured rats.

Granulation tissue in rats was produced by subcutaneous implantation of viscose cellulose sponges. Granulomas, aortae, and skin samples were taken 4, 8, 14, 22, 33, and 42 days after the sponge implantation and compared with age-matched non-operated rats. 14C-proline was given 4 hours before death to animals killed on day 0, 14, and 42. The 14C-OH-proline activity in salt insoluble collagen was higher in granulation tissue and aorta than in skin. This indicates a faster formation, or an increased stability of the intermolecular cross-links in granulation tissue and aorta, than in skin. The percentage of free OH-proline was than in skin, reflecting a relatively increased collagen degradation in granulation tissue. An increased collagen degradation may also, in part, explain a registered higher alpha/beta ratio in collagen from granulation tissue than from skin, as well as the increase in alpha/beta ratio in the older granulomas. The sponge implantation did not affect the collagen of aorta and skin, but caused a decrease in the dry weight of aorta and skin, and an increase in the number of granulocytes in the blood.

Animals↗

PubMed1976

Platelet-collagen interaction. The influence of native and modified collagen (Type I) on the aggregation of human platelets.

Type I collagen from calf skin, collagen modified by pepsin treatment, methylation, succinylation or deamidation, as well as the alpha-chains and cyanogen bromide peptides of the alpha1-chain were investigated with respect to their capacity to induce aggregation of human platelets. These preparations permitted an evaluation of the efficacy of the amino acid sequence, triple conformation,and various fibrillar structures in platelet aggregation. All collagens in dissolved in dissolved form (collagen dissolved at acid pH, pepsin-treated, methylated, deamidated, and succinylated collagen) induced platelet aggregation only after fibril formation. The arrangement of molecules within fibrils is of secondary importance. Modification of the side chains of amino acid residues affects primarily the formation of fibrils. The effect of these side chains on platelet aggregation is masked by the overwhelming potency of the fibrillar forms.

Amino Acid Sequence↗

PubMed1977

Collagen cross-linking alterations in joint contractures: changes in the reducible cross-links in periarticular connective tissue collagen after nine weeks of immobilization.

A significant increase in the NaBH4 reducible intermolecular cross-links in the 9 week immobilized rabbit periarticular connective tissue was found. Dihydroxylysinonorleucine, hydroxylysinonorleucine, and histidinohydroxymerodesmosine were the major cross-links which increased during the period of immobilization. No change in the hydroxlysine/lysine ratio between the immobilized and control periarticular connective tissue collagen was detected during the 9 weeks of enforced immobilization of the rabbit knee. Since the collagen mass in the immobilized periarticular connective tissue does not change, or at most is reduced 10%, we suggest that there is an increase in collagen cross-links expressed both in per unit weight of collagen and on the basis of collagen mass per knee due to the lack of physical stress and motion.

Amino Acids↗

PubMed1976

[Ageing changes in collagen -- in vitro ageing changes in collagen (part III) (author's transl)].

In the present three parts of the survey ageing-changes in collagen physical and chemical qualities are discussed at first. Further a summary on questions of the biosynthesis of collagen, changes of the metabolism in the ageing organism and changes of the ripening collagen in the living organism is given. Following in vitro-ageing-changes of collagen and causes of the changes of the ageing organism are described. A summarizing appreciation of the ageing-changes in the collagen finishes the survey.

Aged↗

PubMed1975

Variations in collagen, non-collagenous proteins, and hexosamine in menisci derived from osteoarthritic and rheumatoid arthritic knee joints.

Knee joint menisci from osteoarthritic and rheumatoid knees were analyzed for nitrogen, collagen, non-collagenous proteins (NCP) and hexamine content. Degenerate areas were analyzed separately. The degenerative areas were significantly lower (P less than 0.005) in collagen but NCP and hexosamines were elevated relative to control tissue. The rheumatoid menisci revealed a reduced level of collagen and hexosamine in areas of localized degeneration. However, the collagen and hexosamine content of the remaining tissue was also diminished (P less than 0.025) relative to normal tissue of the same. age.

Adult↗

PubMed1992

Identification of an immunodominant B-cell epitope in bovine type II collagen and the production of antibodies to type II collagen by immunization with a synthetic peptide representing this epitope.

Using epitope scanning of 272 short, synthetic peptides representing the amino acid sequence of the CB-11 peptide of type II collagen, we have shown that five strains of rat, immunized with type II collagen, produce antibodies to a region 37-45 amino acids from the amino end of CB-11 peptide. Antibodies to this region always gave the highest binding values suggesting that it is an immunodominant region. Wistar rats immunized with a synthetic peptide representing this region, coupled to keyhole limpet haemocyanin, produced antibodies to this peptide which could still be detected at 1:4000 to 1:8000 dilution but none developed clinical arthritis. All sera also showed binding of antibodies to denatured bovine type II collagen but not to native type II collagen, keyhole limpet haemocyanin or to bovine serum albumin by ELISA. Sera from peptide-immunized rats were examined for antibody binding to the 272 short peptides of the CB-11 peptide and to the synthetic peptides representing shortened forms of the immunodominant region and forms of it with substituted amino acids. These results showed that the antibodies in the peptide-immunized rats were not identical to those produced to that peptide by rats immunized with type II collagen but may represent subpopulations of them. These findings suggest caution in interpreting the role of antibodies to individual peptides in arthritis induction without knowledge of their fine specificity.

Animals↗

PubMed1978

[The judgement of collagen metabolism by hydroxyproline in plasma and urine and plasma collagenic peptidase under different diet (author's transl)].

In 34 subjects--coal workers with pneumoconiosis, patients with collagenic diseases and healthy subjects--the daily urinary excretion of hydroxyproline (HP) and the plasma concentrations of HP and of collagenic peptidase have been measured during one week under HP-free and HP-enriched diet. It is shown that a 24-hour period of HP-free diet is necessary and sufficient before collecting urine or plasma for diet independent measurements of total or non-protein bound HP. Concentrations in plasma correlate well with the amounts excreted in urine. Collagenic peptidase is independent from the diet and well suited for assessment of the activity of the metabolism of collagene. There are no differences between healthy subjects and coal workers with pneumoconiosis.

Adult↗

PubMed1977

[Comparison of the cyanogen bromide peptides of vitreous body collagen and type II collagen (author's transl)].

Pepsin-soluble collagen was isolated from bovine vitreous humor. This collagen showed only one alpha-chain in disc electrophoresis, migrating in the alpha1-chain position and between the alpha- and beta-components some colored bands were visible. The disc electrophoretic patterns of the cyanogen bromide peptides of pepsin-soluble vitreous body collagen and pepsin-soluble type II collagen revealed no identity.

Animals↗

PubMed1975

[Stimulating effect of collagen and collagen derivatives on the propregation and adhesion of thrombocytes in defibrinogenated human citrate plasma and in animal citrate plasma].

Collagen type I form calf skin, collagen modified by pepsin, methylation, succinylation or deamidation and alpha1-chains or cyanogen bromide peptides were studied for their effect on adhesion and spreading of platelets. Some of the proteins increased platelet activity and indicated that the following structural parameters are of importance: 1. triple-helical conformation, 2. non-triple-helical regions, 3. charged amino acid side chains, 4. some activity was also detected for cyanogen bromide peptides of collagen alpha1-chain. The activity of collagen when used in a firbrinogen-free system is comparable to that of fibrinogen and potentiates platelet spreading caused by animal plasma.

Afibrinogenemia↗

PubMed1978

Glomerular basement membrane collagen and activities of the intracellular enzymes of collagen biosynthesis in congenital nephrotic syndrome of the Finnish type.

The composition of pepsin-solubilized glomerular basement membrane (GBM) collagen was studied in kidneys from patients with congenital nephrotic syndrome of the Finnish type (CNF). The 3-hydroxyproline content in the GBM collagen in CNF was only about one half of that noted in the controls. The alanine content was slightly higher in CNF, but no differences were found in the contents of the other amino acids or carbohydrates. Analysis of the GBM collagen by sodium dodecyl sulphate polyacrylamide gel electrophoresis after reduction indicated a lower proportion of one of the major polypeptide chains in CNF than in the controls, while a higher proportion of one low molecular weight minor component was noted. The activities of the five intracellular enzymes of collagen biosynthesis, including prolyl 3-hydroxylase, were not significancy altered in the CNF kidney cortex samples when compared with the controls.

Amino Acids↗

PubMed1978

Covalent structure of collagen: amino acid sequence of five consecutive CNBr peptides from type III collagen of human liver.

Type III collagen was solubilized from human liver by limited pepsin digestion and purified by differential salt precipitation and carboxymethylcellulose chromatography. Digestion with cyanogen bromide yielded the nine distinct peptides previously described and an additional tripeptide not recognized in earlier studies. Five of these peptides, alpha1 (III)-CB1, 2, 4, 8, and 10, were further purified by molecular sieve and/or ion exchange chromatography. They contained 12, 40, 149, 125 and 3 amino acid residues, respectively. The amino acid sequence of these peptides was determined by automated Edman degradation of tryptic (before and after maleylation), chymotryptic, thermolytic or hydroxylamine-derived peptide fragments as well as the intact peptides. The alignment of these five peptides within the collagen chain is deduced to be 1-8-10-2-4 by homology with known alpha1 (I) sequences. The known CNBr peptide alignment of the NH2-terminal portion of type III collagen so far would, therefore, be alpha1 (III)-CB3-7-6-1-8-10-2-4 and correspond to the homologous region of alpha1 (I)-CB0-1-2-4-5-8-3 or residues 11-567 of the alpha1 (III) collagen chain.

Amino Acid Sequence↗

PubMed1977

Covalent structure of collagen: amino acid sequence of cyanogen bromide peptides from the amino-terminal segment of type III collagen of human liver.

Human liver type III collagen was prepared by limited pepsin digestion, differential salt precipitation, and carboxymethylcellulose chromatography. Cyanogen bromide digestion of purified type III collagen chains yielded nine distinct peptides. Three peptides, alpha1(III)-CB3, alpha1(III)-CB7, and alpha1(III)-CB6, were isolated by carboxymethylcellulose chromatography and Sephadex G-50 SF gel filtration. Automated Edman degradation together with selective hydroxylamine cleavage and chymotrypsin and trypsin digestion enabled determination of their complete amino acid sequence. Compared with type I collagen, the data show tentative homology of alpha1(III)-CB3 with alpha1(I)-CB1, alpha1(I)-CB2, and alpha1(I)-CB4; alpha1(III)-CB7 with alpha1(I)-CB5; and alpha1(III)-CB6 with the amino-terminal portion of alpha1(I)-CB8. Close interspecies homology was found between the sequences presented here with 90 residues of alpha1(III)-CB3 and 26 of alpha1(III)-CB8 of calf aorta. The present study establishes the amino acid sequence of 229 residues near the amino terminus or nearly one-quarter of the type III collagen chains. The disaccharide, Glc-Gal, was convalently bound to hydroxylysine at a position corresponding to the same location in the alpha1(I) chain.

Adult↗

PubMed1975

A 13C nuclear magnetic resonance and circular dichroism study of the collagen-gelatin transformation in enzyme solubilized collagen.

Natural abundance Fourier transform 13C nuclear magnetic resonance (13C NMR) were obtained for enzyme solubilized collagen at 1 degrees intervals through the transition region. The transition of collagen molecules from the rigid triple helical state to single-stranded, random-coil state is accompanied by a change from broadened carbon resonances unobservable under high-resolution conditions to narrow line spectra. Thus distinction can be made between helical and random-coil states of individual residues. The transition is monophasic, as determined by examination of 14 different carbon resonances, and the entire structure is found to melt cooperatively over a temperature interval of 5 +/- 1 degrees. All the residues seem to be involved in the unfolding process concurrently. The transition was also studied by examining the changes in the circular dichroism spectrum brought about by heating. The experiments corroborated the observation that the transition proceeded cooperatively over a temperature interval of 4 degrees. Enzyme soluble collagen is seen to melt less cooperatively than native collagen. The enthalpy change was determined by assuming an equilibrium between three random coil gelatin chains and tropocollogen molecules. From the enthalpy, the average length of the tripeptide sequences (70-85) involved in the transition can be estimated. The shortening of the cooperative unit could arise as a result of some alteration of the native conformation through proctase treatment.

Animals↗

PubMed1978

Effect of intermittent high altitude hypoxia on the synthesis of collagenous and non-collagenous proteins of the right and left ventricular myocardium.

The incorporation of 14C-proline into collagenous and non-collagenous proteins of the right and left ventricular myocardium was investigated in rats exposed to intermittent high altitude hypoxia. Experimental results have shown that even in control animals significant differences exist in the concentration and synthesis of individual protein fractions between the right and left ventricular myocardium. Long-term exposure to intermittent high altitude hypoxia induced a significantly increased concentration of collagenous and non-collagenous proteins in both ventricles. The incorporation of 14C-proline was not affected at this period (ie period of stabilised hypertrophy) in either of the fractions studied.

Altitude Sickness↗