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Biomedical subjects

M S Hibbs

Publications and source records attributed to M S Hibbs.

26 records · Page 2Linked to original sources
PubMed1985

The role of neutrophils in the development of cadmium chloride-induced emphysema in lathyrogen-fed hamsters.

This study was designed to evaluate the role of neutrophils (PMNs) in the pathogenesis of emphysema. After administration of CdCl2 intratracheally to hamsters fed a lathyrogen, beta-amino propionitrile fumarate (BAPN), the classic lesions of emphysema developed. Administration of specific antineutrophil serum markedly reduced the PMN influx into the lungs which followed CdCl2 exposure and produced a substantial decrease in elastase and collagenase content of bronchoalveolar lavage fluid (BAL). The degree of emphysema in PMN-depleted hamsters given BAPN and CdCl2 was not different from that in hamsters given BAPN and CdCl2. Furthermore, the degree of acute lung injury following CdCl2, as determined by hydroxyproline content of BAL and by lung lipid peroxidation, was the same in PMN-depleted and non-depleted groups. Thus, PMNs were not necessary for the induction of emphysema in BAPN-CdCl2-treated hamsters. The results suggest that PMNs may not be obligate mediators of emphysema.

Aminopropionitrile↗
PubMed1984

Heterogeneity among human collagenases demonstrated by monoclonal antibody that selectively recognizes and inhibits human neutrophil collagenase.

The heterogeneity of human collagenases has been examined using a monoclonal antibody to neutrophil collagenase. This antibody inhibited collagenase activity and, when covalently coupled to Sepharose, bound both latent and active enzyme. Although human neutrophil collagenase was inhibited by the antibody, the activity of human skin and rheumatoid synovial collagenase was not significantly diminished in the presence of the antibody. Competitive inhibition studies also differentiated between these collagenases. Only human neutrophil collagenase effectively blocked the antibody in a competitive enzyme-linked immunosorbent assay while skin and rheumatoid synovial collagenase again failed to interact with the antibody. The unequivocal recognition of neutrophil collagenase as an immunologically distinct entity from other collagenases supports the hypothesis that neutrophil collagenase is a separate gene product from fibroblast or synovial collagenase.

Animals↗
PubMed1984

Secretion of collagenolytic enzymes by human polymorphonuclear leukocytes.

The polymorphonuclear leukocyte contains three proteinases capable of degrading the collagenous components of the connective tissue matrix. These proteinases, gelatinase, interstitial collagenase and elastase, were found to be rapidly secreted by the neutrophil in response to soluble stimuli with maximal accumulation of the gelatinase and interstitial collagenase occurring during a 20 minute incubation. When neutrophils were stimulated with the chemotactic peptide, formyl-met-leu-phe, gelatinase was the predominant collagenolytic enzyme detected. Stimulation of neutrophils with increasing doses of the Ca++ ionophore A23187 lead to a sequential release of collagenolytic proteinases. Gelatinase release was detected at Ca++ ionophore concentrations of .05-.1 microM, while significant release of interstitial collagenase required 0.5-1 microM A23187. Elastolytic activity was detected only at high concentrations of A23187 (5-10 microM). No release of lactic acid dehydrogenase was detected indicating that the enzyme release was not due to cell death. These studies suggest that the neutrophil may modulate its collagenolytic potential by selective release of collagenolytic proteinases.

Collagen↗
PubMed1984

Purification of a type V collagen degrading metalloproteinase from rabbit alveolar macrophages.

A proteinase capable of degrading the helical region of native human type V collagen was identified in serum-free culture medium from "in vivo-activated" rabbit alveolar macrophages. This enzyme was purified to homogeneity using a combination of gel-filtration, ion-exchange and affinity chromatography. Analysis of the purified material by gel electrophoresis revealed a single broad band with relative molecular mass of 82,000 daltons Enzyme activity was eluted from the gel in a region corresponding to the stained band. The protein band was also found to stain positively using the periodic acid-Schiff technique indicating that it was glycosylated. Amino acid analysis revealed a composition rich in acidic residues. The enzyme cleaved type V collagen into three large molecular weight doublets consistent with two cleavage sites within the helix but was inactive against native type I collagen. However, when type I or type V collagen was heat-denatured, the enzyme degraded the alpha chains to small molecular weight peptides.

Amino Acids↗
PubMed1984

Antibody to rabbit macrophage type V collagenase/gelatinase and its use to further characterize the enzyme.

A highly specific antiserum was raised against purified rabbit alveolar macrophage type V collagenase/gelatinase. The reactivity of the antiserum was tested in ELISA and was detected at a high titer. Competitive inhibition ELISA demonstrated a linear inhibition of reactivity by pure antigen if either pure antigen or crude culture medium was used as the solid phase antigen. In the latter case, greater than 90% inhibition was achieved indicating a high degree of specificity of the antibody. Immobilized antibody was successful in absorbing the type V collagenolytic activity. Immunoblot analysis of crude culture medium revealed a single immunoreactive band which correlated with both the stained gel of the purified antigen as well as the only zone of gelatinolysis in a gelatin/acrylamide gel. This monospecific antibody will be a useful tool in the further characterization of this enzyme as well as the delineation of its relative role in chronic inflammation.

Animals↗
PubMed1983

Alterations in collagen production in mixed mononuclear leukocyte-fibroblast cultures.

The cell-cell interactions between fibroblasts and mononuclear leukocytes (MNL) which promote alterations in collagen accumulation were examined using a system of co-culture of human fibroblasts and peripheral blood MNL. The stimulation of collagen production was optimal after 48 h of co-culture and the increase in collagen correlated directly with the number of MNL added. The enhancement of collagen production was seen in both autologous and allogeneic co-cultures. Stimulation of non-collagenous protein was also noted. Co-culture supernatants contained soluble substances that were capable of stimulating collagen production, although they stimulated collagen production to a lesser degree than direct co-culture. Fractionation of these supernatants on Sephadex G-200 revealed a predominant area of stimulatory activity at 160,000 mol wt. Lesser areas of activity were noted at molecular weights of 80,000 and 25,000. Determination of the types of collagen produced by fibroblasts during co-culture with MNL showed that the ratio of type I:III collagen was decreased. These alterations in both the quantitative and qualitative accumulation of collagen mimic the changes often seen in wound healing and early inflammation suggesting that cellular interactions between fibroblasts and MNL may be important in the modulation of collagen production in normal and pathologic states.

Cells, Cultured↗
PubMed1982

Type-specific collagen degradation by eosinophils.

Despite the association of eosinophils with wound-healing and fibrotic processes, their collagenolytic ability has been poorly defined. By using highly purified eosinophil preparations (greater than 95% eosinophils) obtained from guinea-pigs by peritoneal lavage, we have examined type-specific collagen degradation by eosinophils using sensitive detection methods. The results show that eosinophils contain a metalloprotein that degrades types I and III collagens. This activity was apparent only after the addition of 4-aminophenylmercuric acetate to the reaction mixture, a finding similar to that for latent collagenases described from other sources. No collagenolytic activity against types IV and V collagens could be detected. Thus eosinophils may play a role in the alterations in connective-tissue matrices seen in physiological and pathological states.

Animals↗