3 research outputs found
Effect of methylmercury on the rat mast cell degranulation
Methylmercury is the well-known neurotoxicant as weil as a modulator of the immune
system. We investigated the effects of MeHg on the rat mast cell degranulation induced by nonimmunological
stimuli (the selective liberator of histamine, compound 48/80, and calcium
ionophore A23187) both in vivo and in vitro. In 8, 12 and 15 days afterthe final administration of
MeHg we observed the suppression of calcium ionophore A23187-and 48/80-induced histamine
release, which enhanced with time. In experiments in vitro incubation of peritoneal mast cells with MeHg alone in the dose range to did not induce mast cell degranulation, however modified
the activation of mast cells by compound 48/80, and calcium ionophore A23187. We observed
activation of stimulated secretion by preliminary incubation with low dose of MeHg  M and
inhibition by dose of MeHg  M. These results show that MeHg treatment can modify mast cell
function in vivo and in vitro and provide insight into the understanding what role this cell has in the
pathogenesis of Minamata disease-comlected disorders
Evaluation of diatomea algae Thalassiosira weissflogii sensitivity to chloride mercury and methylmercury by chlorophyll fluorescence analysis
Measurement of chlorophyll fluorescence has been shown to be a rapid, non-invasive, and
reliable method to assess photosynthetic performance in a changing environment. In our study, the pulseamplitude-modulation (PAM) - fluorometric method was used to evaluate the sensitivity to chloride mercury
and methylmercury chloride of diatomea microalgae Thalassiosira weissflogii. We found that and  M
MeHg led to a slow decrease in the PSÂ II activity following for prolonged lag phase, whereas the algae was
not sensitive to the same concentrations of HgCl. However observed PS II inactivation by methylmercury
was not complete and about 10Â percents ofthe cells kept the high level of PSÂ II activity as it was shown by
microfluorometric analysis. These cells could determine adaptation of algae to methylmercury effect. Both
toxicants decreased the rate of PS II reparation, as well as increased a heat pathway of excitation dissipation in PS II antennae complex