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B W Case

Publications and source records attributed to B W Case.

26 records · Page 2Linked to original sources
PubMed1986

Asbestos effects on superoxide production. An in vitro study of hamster alveolar macrophages.

Inhaled asbestos induces accumulation of alveolar macrophages (AM) and polymorphonuclear leukocytes (PMN) in lung. Asbestos-enhanced production of superoxide anion (O2-) by AM and/or PMN may be involved in the pathogenesis of asbestos-induced fibrosis, either through direct effects on collagen synthesis or via mediation of tissue injury and repair. In in vivo experiments, bronchoalveolar lavage (BAL) 3 to 8 weeks following intratracheal asbestos injections showed increases in both PMN and AM, with AM representing 78 to 82% of cells recovered. Inhalation models, generally regarded as more analagous to human exposures, have confirmed AM as the predominant component of the cellular response to inhaled asbestos. In this study, the in vitro effects of asbestos fiber on O2- production by AM have been determined in cell populations derived from the Syrian golden hamster. AM for in vitro study were obtained by BAL. O2- production was monitored as superoxide dismutase (SOD) - inhibitable cytochrome c reduction. Significant rises in O2- release by AM were noted in the presence of 0.4 mg/ml crocidolite (2.53 +/- 0.33 nmole cytochrome c reduced/10(6) cells/30 min, 37 degrees C; controls 1.13 +/- 0.18 nmole; P less than 0.02). Chrysotile induced levels of O2- release in AM which were similar to those evoked by crocidolite.

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PubMed1979

Immunoblastic lymphosarcoma: a light, immunofluorescence, and electron microscopic study.

Immunoblastic lymphosarcoma (ILS) is a newly recognized malignant lymphoreticular neoplasm and is included in the recent W.H.O. classification of lymphomas. This report concerns six cases of ILS studied by light, immunofluorescence (IF), and electron microscopy (EM). Four patients were female and all except one were over 50 years of age. Four patients had some immunological abnormality. Light microscopy showed a monomorphic population of immunoblasts with pyroninophilic cytoplasm and variable plasmacytoid differentiation. Intracytoplasmic IgG was demonstrated by IF in four cases, and IgA in one. Large lymphoid cells with varying proportions of polysomes, rough endoplasmic reticulum, and Golgi apparatus were seen by EM in four cases. Mean survival was 4.8 months in five cases; death in four was due to disseminated ILS. We concluded that our cases of ILS are of B cell origin, are often associated with immunological abnormalities, and carry a poor prognosis. Immunofluorescence and EM are helpful in its diagnosis.

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PubMedDate not supplied

Environmental and occupational exposures to chrysotile asbestos: a comparative microanalytic study.

Previous light microscopic analysis of lung tissue from persons living close to a large open-pit asbestos mine demonstrated asbestos body counts intermediate between those of referents and those of miners and millers. In this study, we examined via electron microscopy and x-ray energy dispersive spectrometry autopsy lung specimens from individuals ascertained to be environmentally or occupationally exposed and from a referent group. Environmental group concentrations of chrysotile fibers longer than 5 microns were significantly higher than those of referents, and 50% lower than those observed in the occupational group. Tremolite was markedly increased in the occupational group, but only marginally greater in the environmentally exposed. Electron-microscopy-derived concentrations of amphibole fibers longer than 5 microns correlated well with light microscopic asbestos body counts in the occupational group but not in the environmental or referent groups. Chrysotile concentration was not related to asbestos body concentration in any group. Crocidolite fiber, a commercial amphibole not native to the region, was nonetheless identified in lung tissue from 15 of 23 chrysotile miners and millers. Environmental exposure to asbestos fiber as a result of residence within 40 km of the mines results in increased lung chrysotile content.

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