Melatonin and thermal stress regulate differential expression of heat shock proteins and melatonin receptors in spleen of mice.

Cellular defence by expression of heat shock proteins (Hsps) against stress stimulation is the most universal phenomenon in stress physiology. Melatonin is well known as an anti-stress molecule possessing hypothermic effects. It protects cells and tissues in stressed conditions. Individually, Hsp70 and melatonin shows its functional ability in stressed organisms as well as in immune functions. The aim of the present study was to determine the interaction of melatonin receptors (MT1/MT2) in exogenous melatonin modulated expression of heat shock proteins (Hsp70/Hsc70) in spleen of thermally stressed male mice. Results of the study showed thermal stress significantly increased the Hsp70/Hsc70 and melatonin receptor MT2 expression in spleen of mice. The administration of melatonin significantly increased Hsp70 expression, but decreased Hsc70 expression. Both MT1/MT2 receptor expressions increased after melatonin treatment, whereas thermal stress to melatonin treated mice showed decrease in MT1/MT2 receptor expression than the only melatonin treated mice. MT2 receptor is responding in all experimental conditions corresponding to changes in Hsp70 protein expression. Therefore, the present study might suggest that MT2 receptor is interacting in coordination of melatonin mediated heat shock proteins expression in mice spleen after thermally stressed conditions.

Tsunami, post-tsunami malaria situation in Nancowry group of islands, Nicobar district, Andaman and Nicobar Islands.

Background & objectives: Due to tsunami in 2004 a large proportion of population in Nicobar group of Islands become homeless, and in 2006 large scale labour migration took place to construct the houses. In 2008, a significant increase in malaria incidence was observed in this area. Therefore, in March 2008, the situation of malaria was assessed in Nancowry Islands in Nicobar District to study the reasons for the observed upsurge in the number of cases, and to suggest public health measures to control the infection. Methods: The methods included a retrospective analysis of long term trend in the behaviour of malaria over the years from 2001 to 2008, analysis of the acute malaria situation, and rapid fever and malaria parasitemia survey along with environmental component. Mass radical therapy (MRT) and post-intervention parasitemia survey were carried out. The malaria situation in the aftermath of MRT was analysed. Results: During the post tsunami year (2005) there was a large increase in the incidence of malaria and this trend continued till 2008. The percentage of Plasmodium falciparum increased from 23 to 53 per cent from 2006 to 2007 that coincides with the labour influx from mainland. The study showed that Nancowry was highly endemic, with high transmission setting, and high risk area for malaria. Though, more number of migrant labourers suffered fever (75 vs 20%) and sought malaria treatment over past month but parasitemia survey showed higher point prevalence of malaria among native tribes (7.4 vs 6.5%). Post-MRT, there was a decline in the occurrence of malaria, though it did not last long. Interpretation & conclusions: The study findings suggest that the migrant workers hailing from non-endemic or moderately endemic settings became victims of malaria in epidemic proportion in high endemic and high transmission setting. To find out the reasons for deterioration of malaria situation at Nancowry in the aftermath of tsunami requires further research.