Biomedical subjects
Publications and source records attributed to R M Flynn.
Activated partial thromboplastin times (APTT) were determined for citrated plasma samples obtained from healthy Beagle dogs. Significant variations were observed with different reagents and analysers in these studies emphasizing the importance of analytical variables in APTT measurements.
In this study, we analyzed the expression of genes encoding for components of the phagocyte superoxide anion-generating system in human phagocytes treated with interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS). Human neutrophils express high levels of the 47-kDa cytosolic factor (p47-phox), which are down-regulated after treatment with IFN-gamma, but not with LPS. On the contrary, the steady-state levels of the heavy chain subunit of cytochrome b558 (gp91-phox) were increased by IFN-gamma and LPS in human monocyte-derived macrophages and neutrophils in a time- and dose-dependent fashion, whereas cytochrome b558 light chain subunit (p22-phox) mRNA was not influenced by either agent. Studies on post-transcriptional regulation at the level of mRNA stability indicate that, in neutrophils, IFN-gamma has no influence on gp91-phox and p47-phox mRNA half-lives. The content of the two cytochrome b558 subunits was quantified by enzyme-linked immunosorbent assay, which revealed that, in neutrophils, gp91-phox levels doubled after 4 h of treatment with IFN-gamma or LPS. Monocyte/macrophage maturation was associated with a gradual decrease in gp91-phox mRNA and protein levels, which were both restored by treatment with IFN-gamma for 24-48 h. These results suggest that induction of the gp91-phox gene and protein product by IFN-gamma or LPS is an important requirement in the mechanism of the enhancement of neutrophil and macrophage oxidative metabolism.
Immune interferon (IFN-gamma) induces in human neutrophils accumulation of the mRNA for the high affinity receptor for monomeric IgG (Fc gamma R-I, CD64) with a mechanism that is independent from de novo protein synthesis and from activation of the Na+/H+ antiporter. Monocyte-derived macrophages can also be induced to express high levels of Fc gamma R-I mRNA by IFN-gamma, without requirement of protein synthesis. Unlike what is observed in neutrophils, induction by IFN-gamma of macrophage Fc gamma R-I mRNA was significantly depressed by the Na+/H+ antiporter inhibitor amiloride. These results indicate that phagocytes' Fc gamma R-I mRNA induction by IFN-gamma is regulated by different mechanisms depending on the target cells.
Explore the source record for details and available documents.
An immunogold procedure using the monoclonal antibody F3-20-7 to canine Thy-l has been used to label T-lymphocytes in peripheral blood samples taken from healthy Beagles. By this method, approximately 64% of peripheral blood lymphocytes were identified as T-lymphocytes.
A method using monoclonal antibodies in conjunction with an immunogold procedure was adapted for labelling T lymphocytes in blood samples obtained from male Wistar rats. The monoclonal antibodies W3/25, MRC/OX8 and W3/13 were used. Changes in the percentages of positively labelled cells were observed in rats dosed with the immunosuppressant cyclosporin.