Search PubMed⌕ Search

Biomedical subjects

C A Shuttleworth

Publications and source records attributed to C A Shuttleworth.

At least 73 records · Page 4Linked to original sources
PubMed1987

The fibrous capsules around static and dynamic implants: their biochemical, histological, and ultrastructural characteristics.

In this article, we report the findings of a small study comparing the histological, ultrastructural, and biochemical features of fibrous capsules formed around tissue-expanding devices (dynamic implants) and simple prostheses (static implants) in the human. Histologically and biochemically, the dynamic fibrous capsule appears to represent an early phase of scar tissue formation around an expanding foreign body, the dominant feature being increased cellularity caused by myofibroblasts. In view of the marked presence of these contractile elements, it is paradoxical that a lower capsular contracture rate should be reported to occur in breast reconstruction using a temporary expander. This lower rate presumably is because these myofibroblasts undergo modulation once the expansion process has ceased and the final prosthesis is in place. One may also assume that the fibrous capsule would retain features of early scar tissue if the expansion process is maintained indefinitely. This hypothesis can be evaluated by a long-term study in the animal.

Cicatrix↗
PubMed1986

Type VI collagen and glycoprotein MFPI are distinct components of the extracellular matrix.

Two collagenous glycoproteins, Mr 140,000 and Mr 150,000, are synthesized and secreted into the medium of cultured fibroblasts. The glycoprotein of Mr 140,000 is identical with the 140K(VI) component of type VI collagen by both immunological and physicochemical criteria. The glycoprotein of Mr 150,000 is immunologically distinct and exhibits the physicochemical characteristics of the putative elastic microfibrillar glycoprotein MFPI.

Animals↗
PubMed1985

Isolation from bovine elastic tissues of collagen type VI and characterization of its form in vivo.

Foetal-bovine nuchal ligament and aorta, together with adult-bovine aorta and pregnant uterus, were extracted under dissociative conditions in the absence and in the presence of a reducing agent. A collagenous glycoprotein of Mr 140000 [designated component 140K(VI)], identified in these extracts as the major periodate/Schiff-positive component, was shown to be related to collagen type VI. Digestion of non-reduced extracts with pepsin yielded periodate/Schiff-positive peptides that, on the basis of their electrophoretic mobilities, amino acid analyses and peptide 'maps', were identical with type VI collagen fragments prepared by standard procedures. It is concluded that collagen type VI occurs in vivo as molecule comprising three chains of Mr 140000 in which the helical domains account for about one-third of each polypeptide. Biosynthetic experiments with nuchal-ligament fibroblasts in culture demonstrated that a bacterial-collagenase-sensitive [3H]fucose-labelled glycoprotein, Mr 140000, was immunoprecipitated from culture medium by a specific antibody to the pepsin-derived form of collagen type VI. This result suggests that the collagenous polypeptides [140K(VI) components] represent the biosynthetic precursors of type VI collagen that do not undergo processing to smaller species before deposition in the extracellular matrix. Analyses of 5M-guanidinium chloride extracts of tissues with markedly different elastin contents and at different stages of development suggested that there was no relationship between collagen type VI and elastic-fibre microfibrils, a conclusion supported by the observation that the immunoprecipitated glycoprotein, Mr 140000, was distinct from the glycoprotein MFPI, Mr 150000, believed to be a constituent of these microfibrils [Sear, Grant & Jackson (1981) Biochem. J. 194, 587-598].

Amino Acids↗
PubMed1984

Collagen heterogeneity and quantification in developing bovine nuchal ligament.

The collagenous components were investigated in peptic digests of developing bovine nuchal ligament. Types I and III collagen were the major species isolated, but the presence of types IV, V and VI was also shown. Changes in the pepsin-susceptibility of nuchal ligament during foetal development were observed. CNBr-cleavage peptide analysis indicated that type I collagen became cross-linked rapidly, as evidenced by the lack of alpha 1(I)CB6. At present it is not clear if this decrease in pepsin-susceptibility is due to cross-linking of collagen, to increased deposition of elastin, or to both. Quantification of collagen types I and III was shown to depend on the method used. When pepsin-solubilized material was examined an apparent increase in type III collagen with respect to foetal age was observed, whereas when CNBr digests of intact ligament were examined a relatively constant amount of type III collagen (approx. 24%) was found. The constant amount of type III collagen observed during foetal development changed at birth and increased in mature nuchal ligament to represent approx. 45% of the total collagen.

Amino Acids↗
PubMed1984

A collagenous glycoprotein found in dissociative extracts of foetal bovine nuchal ligament. Evidence for a relationship with type VI collagen.

A collagenous glycoprotein (Mr 140000) was isolated from dissociative extracts of foetal bovine nuchal ligament and purified by a combination of ion-exchange and gel-filtration chromatography. This glycoprotein (designated MFPI) exists as a large-Mr disulphide-bonded aggregate in the absence of a reducing agent. The purified glycoprotein was shown to contain about 6% (w/w) carbohydrate, mostly as galactose, glucose and mannose. Amino acid analysis showed the presence of hydroxyproline and hydroxylysine, indicative of its collagenous nature. The collagenous nature of this glycoprotein was further investigated by enzyme digestion. Pepsin digestion produced three major fragments, which were identical with peptides of type VI collagen. Bacterial-collagenase digestion of the unreduced glycoprotein also produced several discrete peptides. However, reduction of the glycoprotein before bacterial-collagenase digestion resulted in the degradation of these discrete peptides. Glycoprotein MFPI extracted in dissociative conditions appears to be a larger-Mr form of type VI collagen, believed to originate from microfibrillar components in the intact tissue.

Amino Acids↗
PubMed1984

Synthesis and secretion of sulphated glycosaminoglycans by bovine peridontal ligament fibroblast cultures.

The cultures were allowed to incorporate 35SO2-4 for various periods of time. 35S-labelled macromolecules were isolated from the medium, a trypsin digest of the cells and the cell residue. Ion-exchange chromatography separated the radioactive polysaccharides into heparan sulphate and a galactosaminoglycan population. Most heparan sulphate was in the trypsin digest and cell residue fractions. The galactosaminoglycan fractions were investigated by differential degradations with chondroitinase ABC and AC and ethanol fractionation. The medium galactosaminoglycans contained both glucuronic and iduronic acid residues and existed in copolymeric structures as chondroitin sulphate/dermatan sulphate hybrid molecules. Dermatan sulphate was also detected. In contrast, the trypsin-digest fraction contained mainly chondroitin sulphate-like molecules.

Animals↗
PubMed1982

[Lathyrism and collagens I and III (author's transl)].

The administration of lathyrogenic agents (BAPN) at weak and prolonged doses (9 weeks, 1 g/kg/day) induced in the rat simultaneous alterations of aortic and cutaneous connective tissues comparable to the modifications observed during ageing in man. The lathyrogens produced this effect of inhibiting lysine-oxydase, the enzyme responsible for cross-linking collagen and elastin which leads to an increase in extractable collagen in the tissues. But BAPN did not appear to affect synthesis of collagen either in amount or in types I and III collagen ratio.

Aging↗
PubMed1982

Biosynthesis of glycoproteins by rabbit dental pulp fibroblasts in culture.

Confluent dental pulp fibroblast cultures incorporated L-[3H]-fucose in a linear manner with time into non-diffusible macromolecules over 24 h. Ascorbate supplementation did not appear to alter the amount or type of macromolecules. Equilibrium CsCl-density-gradient centrifugation established that the [3H]-fucose-labelled macromolecules released into the medium were predominantly glycoproteins. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis showed that the major fucosylated glycoprotein had an apparent molecular weight of 230,000, but several other species were also seen. The major fucosylated glycoprotein was fibronectin by its affinity for gelatin and its immunoprecipitation with a specific anti-(cold-insoluble globulin).

Animals↗
PubMed1982

Lathyrism: aortic and cutaneous collagen in the rat.

In the rat the administration of lathyrogenic toxic agents at low doses over prolonged periods of time caused simultaneous alterations in aortic and cutaneous tissues. BAPN caused an increase in soluble collagen in the skin, but in aorta there was no increase in neutral salt soluble collagen, but an increase in the amount that could be solubilized with pepsin. Type III collagen was found to represent 7% in the control aorta samples and this level was not affected by BAPN. In skin Type III accounts for 11% of the extractable collagen in controls and 14% in lathyritic animals. Biochemical changes observed in this study show evidence for collagenous lesions by increases in solubility in both skin and aorta but in neither tissue was the percentage of Type III altered by lathyrism.

Aminopropionitrile↗
PubMed1982

[Lathyrism and collagens I and III (author's transl)].

The administration of lathyrogenetic agents (BAPN) at weak and prolonged doses (9 weeks, 1 g/kg/day) induced in the rat simultaneous alterations of aortic and cutaneous connective tissues comparable to the modifications observed during ageing in man. The lathyrogens produced this effect by inhibiting lysine-oxydase, the enzyme responsible for cross-linking collagen and elastin which leads to an increase in extractable collagen in the tissues. But BAPN did not appear to affect synthesis of collagen either in amount or in types I and III collagen ratio.

Aminopropionitrile↗
PubMed1978

The presence of type III collagen in the developing tooth.

Type I and type III collagens have been isolated from dental papilla and dental pulp of bovine tissues by enzymic digestion with pepsin and differential salt precipitation. Type III collagen was further purified by molecular sieve and ion-exchange chromatography. The relative proportions of type III and type I collagens were estimated by two different techniques, gel electrophoresis in the presence of mercaptoethanol, and direct estimation of the alpha1(III)CB3 peptide. Both techniques gave similar values. Type III collagen constituted 24% of papilla and 28% of pulp collagen by the first procedure, and 20% and 31% by the second. 18% of dental follicle collagen was type III.

Amino Acids↗