Lipoteichoic acid improves the capability of mast cells in the host defense system against bacteria.

Objectives And Design: We investigated the effects of microbial components on the uptake of microbes by mast cells (MCs), and studied the change in cytokine production in MCs after bacterial uptake.

Material Or Subjects: LAD2 human mast cells, cord-blood and peripheral-blood derived MCs were employed to analyze their surface molecule expression and cytokine generation by flow cytometry. Bacterial internalization in these MCs was observed by confocal microscopy and flow cytometry.

Lipoteichoic acid downregulates FcepsilonRI expression on human mast cells through Toll-like receptor 2.

Background: FcepsilonRI on the surface of mast cells (MCs) plays a central role in allergic responses. Recent evidence shows that exposure to microbial components corresponds with a significant reduction in the risk for allergic diseases. Although many reports suggest that this is due to changes in T-cell functions, how MC functions are altered by bacterial infection remains unknown.

The protective effect of H2-receptor activation against the duration of myocardial hypoxia/reoxygenation-induced ventricular fibrillation in sensitized guinea-pig hearts.

Patients with high serum immunoglobulin E levels were reported to be protected against sudden death during acute myocardial infarction. The protection mechanism might be attributed to the facilitation of histamine release from sensitized mast cells; however, this remains to be clarified. In this study, we examined the influence of sensitization on ventricular fibrillation (VF) induced by myocardial hypoxia/reoxygenation (H/R).

Enzymatic measurement of tryptase-like protease release from isolated perfused guinea pig heart during ischemia-reperfusion.

To elucidate the details of tryptase release from the heart during ischemia-reperfusion (I/R), we attempted the enzymatic measurement of tryptase release from the isolated guinea pig heart perfused by the Langendorff mode I/R model. Tryptase-like activity in the effluent was monitored by the hydrolysis of L-Pyr-Gly-Arg-MCA. Tryptase-like protease and histamine were rapidly released from heart during ischemia within 10 min.