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Biomedical subjects

S Gay

Publications and source records attributed to S Gay.

At least 289 records · Page 16Linked to original sources
PubMed1976

Immunohistological study on collagen in cartilage-bone metamorphosis and degenerative osteoarthrosis.

Synthesis of collagen by chondrocytes was studied by immunofluorescence using antibodies specific for type I, II and III collagen. The following tissues and culture conditions were chosen for this immunohistological study: normal articular cartilage, epiphyseal growth cartilage, cartilage undergoing osteoarthrotic degeneration, suspension culture and monolayer culture. While type II collagen is the unique collagen all over hyaline cartilage, type I collagen is produced by hypertrophic chondrocytes in the growth plate. In addition, chondrocytes in osteoarthrotic areas of articular cartilage synthesize type I collagen. Under in vitro culture conditions, chondrocytes initially product type II collagen and synthesize later on type I collagen. The change of synthesis from type II to type I collagen is more rapid in monolayer than in suspension culture. It is concluded that the presence of matrix compounds and the cellmatrix interaction as well are necessary to maintain synthesis of type II collagen in chondrocytes. Alterations in the cell-matrix interactions are shown to occur in the hypertrophic zone of the epiphyseal growth plate, in cartilage undergoing osteoarthrotic degeneration as well as in chondrocytes grown in culture. Thus, change in the control of gene activity may subsequently lead to change in collagen synthesis. It is possible that the synthesis of type I collagen, which cannot fulfil the physiological function of a structural element in cartilageneous tissue, is a crucial factor in the process of osteoarthrosis.

Cartilage↗
PubMed1976

Characterization and distribution of collagen types in arterial heterografts originating from the calf carotis.

The immunohistochemical results showed that the distribution of the collagen types in calf carotis is the same as that found in human arteries. Mechanically prepared and ficin-treated vessels showed a removal of cells, elastic fibres and type II collagen. The remaining collagen meshwork was shown by immunohistochemical methods and also by amino acid analysis to be type I collagen. Because of its structural, chemical and immunological properties, the protease treated, aldehyde stabilised Arteria carotis communis of the calf is suitable as a replacement material for arterial segments. Initial successes using man as a recipient support the stated conclusion.

Amino Acids↗
PubMed1976

Preparation and use in immunohistology of antibodies specific for type I and type III collagen and procollagen.

Antibodies to bovine type I and type III collagen and their precursor form procollagen were produced in rabbits and rendered specific for the immunizing antigen by immunoadsorption. These purified antibodies showed distinct immunofluorescence staining on frozen sections of both bovine and human connective tissue at concentrations as low as 1-10 mug/ml. Antibodies to type III collagen and procollagen reacted with reticulin in liver and spleen, with fascicles around tendons and with the upper portion of the dermis. Antibodies to type I collagen and procollagen reacted with skin and fiber bundles in tendon but did not stain reticulin. No reaction was observed with cartilage collagen or with kidney glomerular basement membrane.

Animals↗
PubMed1976

Vitamin A-containing lipocytes and formation of type III collagen in liver injury.

Hepatocellular necrosis in carbon tetracholride-induced injury of rats is associated with an accumulation of lipocytes (perisinusoidal cells or Ito cells) containing fat droplets and giving vitamin A fluorescence. In the subsequent formation of connective tissue septa, transitional cells having morphologic characteristics of lipocytes and fibroblasts are abundant and are associated with the appearance of type III collage-. The features suggest that the lipocyte is the precursor of the fibroblasts responsible for parenchymal fibrillogenesis and under these conditions forms type III collagen. The process is a postulated link between hepatocellular necrosis and fibrosis.

Animals↗
PubMed1976

Simultaneous synthesis of types I and III collagen by fibroblasts in culture.

Specific antibodies against types I and III collagens and procollagens were used to localize these proteins in cultured human cells. These studies indicate that the same cell makes both proteins. No type III procollagen synthesis was observed in cells from two patients with two patients with the Ehlers-Danlos type IV syndrome.

Ascorbic Acid↗
PubMed1976

Recongnition by guinea-pig peritoneal exudate cells of conformationally different states of the collagen molecule.

Guinea-pig peritoneal exudate cells were tested in vitro in the presence or absence of specific antiserum to native collagen for their capacity to discriminate between native and denatured collagens of various species. Adherent exudate cells bound denatured collagens, regardless of the origin of the collagen or the presence of serum. The binding was reduced if the cells were pretreated with trypsin. Recovery of binding was mediated by a normal serum component resembling an IgM antibody to denatured collagen. In the presence of normal serum, native collagen was only marginally bound, apparently in a non-specific manner. Uptake of native heterologous collagens was greatly increased in the presence of specific antiserum to native collagen with specificity of binding reflecting the type of collagen. Binding of denatured and native collagen occur via independent mechanisms.

Animals↗
PubMed1976

Production and specificity of antibodies against the aminoterminal region in type III collagen.

A cross-linked fragment (peptide T1X) with a molecular weight of 13,000 could be isolated from a tryptic digest of insoluble type III collagen of calf skin. Peptide T1X was conjugated on to bovine serum albumin by glutaraldehyde and used for immunization of rabbits. The antisera reacted in passive haemagglutination and radioimmune assay with peptide T1X, type III collagen and its constituent alpha1(III) chain. Little or no reaction was observed with type I collagen and alpha1(I) chain. While rabbit antisera to neutral salt-soluble type III Collagen also showed a strong binding for 125I-labelled peptide T1X much less reaction was observed with antisera to type I collagen. The antigenicity of type III collagen was largely destroyed by pepsin treatment suggesting that it resided in non-helical segments. A fragment of peptide T1X produced by digestion with collagenase retained antigenic activity. The data indicated that the aminoterminal region of type III collagen contains strong antigenic determinants located in a non-helical sequence of about sixteen amino acids. Antibodies to these antigenic determinants were purified and rendered specific for type III collagen by immunoadsorption. The antibodies stained in indirect immunofluorescence tests particularly those regions in various connective tissues which are rich in reticulin fibres. Different staining patterns were observed with antibodies to type I collagen.

Antibodies↗
PubMed1976

[The polymorphism of collagen. New viewpoints on the structure and function of connective tissue].

Recent studies have established that connective tissue contains several chemically and genetically distinct collagens. Here we discuss the nature of these proteins, their occurrence in different tissues and their involvement in disease processes. Types I, II and II collagens show some similarities indicating a common origin. Morphological studies using antibodies against the various collagens indicate that the different collagens occur in different anatomical structures. Alterations in the distribution of these collagens are seen in tissues in certain disease states and may cause the loss of normal tissue function.

Age Factors↗
PubMed1975

Disturbance in the regulation of the type of collagen synthesized in a form of osteogenesis imperfecta.

Fibroblasts derived from skin biopsies of a patient with a congenital defect of connective tissue revealed a disturbance in collagen synthesis. The defect was found in the mechanism that controls the type of collagen synthesized. Biochemical data as well as evaluation of immunofluorescent micrographs using collagen type-specific antibodies, suggested that the fibroblasts of this patient synthesized type III collagen, at a time and rate which was not found in fibroblasts from an age-matched healthy individual.

Cells, Cultured↗
PubMed1975

Immunohistochemical evidence for the presence of collagen type III in human arterial walls, arterial thrombi, and in leukocytes, incubated with collagen in vitro.

Sections of arterial walls and of thrombi and smears of leukocytes previously incubated in vitro with collagen type III were examined by immunohistochemical technique for the presence of collagen types I, II and III. In arterial walls collagen type III was detected immediately underlaying the endothelial cell layer and in the tissue between tunica elastica interna and adventitia. Collagen type I was not shown in the subendothelial layer. Fresh thrombi contained occasionally collagen, but only of type III. This was associated with leukocytes. Leukocytes were capable in vitro to associate and/or phagocytose collagen type III and this could be visualized immunohistochemically. The data show that collagen type III in vivo may play a crucial role in the initiation of thrombus formation.

Amino Acid Sequence↗
PubMed1975

[Immunohistochemical characterization of collagen in liver cirrhosis (author's transl)].

Using indirect immunofluorescence technique, 21 cases of hepatic cirrhosis of differing etiology were studied with type-specific antibodies to collagen type I, II, and III. In all cases the fibrous septa and portal tracts showed an increase in type III collagen. No fluorescence could be observed with antibodies to collagen type I and II. Thus, biochemical studies are supported which show, in addition to type III collagen, a new, as yet undescribed type of collagen in liver cirrhosis that is similar to type I collagen electronmicroscopically, but differs from type I collagen biochemically and immunologically. No correlation between the etiology of cirrhosis and the pattern of different collagen types could be found. The origin of different collagen types in liver cirrhosis is briefly discussed.

Adult↗
PubMed1975

Liver cirrhosis: immunofluorescence and biochemical studies demonstrate two types of collagen.

Pepsin solubilization of small and large noduled liver cirrhosis yielded two types of collagen (precipitated at 1.7 and 2.5 M NaCl concentrations) as demonstrated by electronmicroscopy. The 1.7 M NaCl precipitate was identified as type III collagen using an immunofluorescence technique. The 2.5 M NaCl precipitate appeared to be type I in the electronmicroscope. However, immunofluorescent and biochemical studies indicated that it was not type I but a type of collagen not yet described.

Aged↗