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Biomedical subjects

M M Chaves

Publications and source records attributed to M M Chaves.

At least 19 recordsLinked to original sources
PubMed1996

Effect in vitro of gamma interferon and interleukin-10 on generation of oxidizing species by human granulocytes.

We examined the effect of interleukin-10 (IL-10), gamma interferon (IFN-gamma), phorbol ester (PDB), opsonized zymosan (OZ) and aminophylline (a cAMP phosphodiesterase inhibitor) on the reducing power and oxidizing species generation by human neutrophils, using MTT dye reduction and luminol-dependent chemiluminescence assays, respectively. Gamma interferon (IFN-gamma), phorbol ester (PDB) and opsonized zymosan (OZ) were activators while interleukin-10 (IL-10) and aminophylline were inhibitors. A strong parallelism was observed between oxidizing species generation and cellular reducing power in both activation and inhibition experiments. Our results also demonstrate for the first time the effect of IL-10 on free radical generation by neutrophils. The consequence of these activating and inhibiting effects on the inflammatory process are discussed.

Free Radicals↗
PubMed1991

A microcalorimetric assay to measure the reactivity of antigen-stimulated mononuclear cells from Schistosoma mansoni-infected patients.

The reactivity of mononuclear cells (2 x 10(6)/ml minimum Eagle's medium, MEM) from normal subjects and from Schistosoma mansoni-infected patients was evaluated by microcalorimetry. The results which are reported as heat production (mcal for 2 x 10(6) cells in 3600 s), were 2,087 +/- 21.3 and 2,497.0 +/- 21.3 for mononuclear cells from infected patients (N = 8) under stimulation with S. mansoni soluble egg antigen (SEA) and soluble adult worm antigenic preparation (SWAP), respectively. The values for cells from normal subjects (N = 8) were 13.7 +/- 1.1 and 29.3 +/- 3.2 in the presence of the same antigens. Pre-treatment of mononuclear cells from patients with 1 mM aminophylline (a cAMP phosphodiesterase inhibitor) totally abolished heat production. Cell viability (greater than 95%) was not changed after the measurement. The microcalorimetric assay described here measures the cellular metabolic activity and we feel justified in suggesting this technique as an auxiliary diagnosis of schistosomiasis. Given the sensitivity, precision and accuracy of this microcalorimetric assay, we feel it can be used for the diagnosis of disease conditions for which a reliable diagnostic method is required.

Animals↗
PubMed1990

Correlation between the lack of mononuclear cell cytotoxicity against schistosomula in vitro and inositolphosphate turnover in patients with schistosomiasis.

A comparison was made of the reactivity of mononuclear cells from normal subjects and from S. mansoni-infected patients. The following parameters were evaluated: 1) ability of mononuclear cells to kill schistosoma in the presence of complement; 2) [3H]-inositol incorporation into phosphatidylinositol (PI) and the rate of inositolphosphates (IPx) released. Cells from normal subjects, but not from S. mansoni-infected patients, were able to kill schistosomula in vitro. A decrease in inositolpolyphosphates (IPx) was observed for phytohemagglutinin (PHA)-stimulated mononuclear cells from infected patients when compared with mononuclear cells from normal subjects after 24 h of incubation. The results suggest that the reactivity of mononuclear cells from infected patients is altered under conditions of nonspecific stimulation with PHA when compared with normal cells.

Animals↗
PubMed1988

Modulation of sheep erythrocyte receptor expression by anti-CD4, anti-CD8, and anti-HLA antibodies.

The modulation of E receptors on T cells by anti-CD4 and/or anti-CD8 is reported. The percentage of E rosette-forming cells (RFC) was decreased when sheep erythrocyte and mononuclear cells were incubated in the presence of monoclonal antibodies anti-CD4 and/or anti-CD8. This inhibition was not due to shedding of the E receptor and it was reversed by 8-Br.-3',5' cyclic guanosine monophosphate (cGMP). In contrast, anti-HLA antibodies induced an enhancement of sheep erythrocyte receptor expression evaluated by RFC.

Antibodies↗