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Biomedical subjects

M A McCarthy

Publications and source records attributed to M A McCarthy.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Inhibition of polyamine synthesis suppresses human lymphocyte proliferation without decreasing cytokine production or interleukin 2 receptor expression.

Difluoromethylornithine (DFMO) irreversibly inhibits ornithine decarboxylase (ODC), a crucial enzyme in polyamine synthesis, and impairs mitogen-induced lymphocyte proliferation. To examine the mechanism of action of DFMO, we studied the effect of this ODC inhibitor on lymphokine production and interleukin 2 (IL 2) receptor expression. DFMO decreased thymidine uptake of peripheral blood mononuclear cells stimulated by the mitogens phytohemagglutinin, concanavalin A, phorbol myristate acetate and ionomycin 60-70% compared with untreated cells, and the inhibition could be completely reversed by 10 mM spermidine. DFMO had no effect on IL 1 production by monocytes exposed to silica particles. Concentrations of IL 2 increased 7-fold in DFMO-treated, PHA-stimulated PBMC cultures, compared with untreated cells; whereas IL 2 receptor expression as measured by the anti-Tac monoclonal antibody was not affected by the inhibition of ODC. Mixing experiments using cells cultured with or without DFMO indicated that the inhibition by DFMO was not mediated by suppressor cells. Our results strongly support the concept that polyamines are required for a relatively late event in lymphocyte activation occurring after the interaction of IL 2 and its receptor.

Biogenic Polyamines↗
PubMedDate not supplied

Illness in hemodialysis patients after exposure to chloramine contaminated dialysate.

In September 1987, patients at an outpatient dialysis center were exposed to chloramine contaminated dialysate when the carbon filter in a recently modified water treatment system failed. Forty-one patients required transfusion to treat the resultant hemolytic anemia. Epidemiologic investigation demonstrated that the mortality rate among dialysis center patients increased during the 5 months after chloramine exposure when compared with the 12 months before chloramine exposure, but no deaths could be attributed to the exposure. Chloramine is commonly used as a disinfectant in municipal water supplies, and has previously been reported to cause hemolytic anemia in patients undergoing dialysis. Hemodialysis centers in cities that use chloramine in water supplies must design water treatment systems with adequate means for removing chloramine and must monitor processed water closely to ensure that chloramine contamination does not occur. Dialysis centers that make changes in their water processing systems should evaluate all components of the system before changes are made, and must ensure that after modifications are made, processed water meets the standards set by the Association for Advancement of Medical Instrumentation.

Ambulatory Care Facilities↗