Lithium neurotoxicity at therapeutic level--a case report.

A 30 years old Hindu male presenting with symptoms of lithium toxicity. On investigation, serum lithium level was found to be 0.5 meq/l. Though toxicity at this level of lithium is unusual, still neurotoxicity happened to be the cause of his hospital admission. He was debarred from taking lithium further and carbamazepine was started as mood elevator. He responded favourably.

Effect of cis and trans unsaturated fatty acids on the transport properties of Salmonella typhimurium.

The transport of α-methyl-D-glucoside and two aminoacids, L-phenylalanine and L-leucine by a temperature sensitive fatty acid requiring mutant of Salmonella typhimurium was studied under conditions of supplementation with cis or trans-unsaturated fatty acids. The results of such experiments definitely establish a relationship between the fatty acids composition of the membrane and the transport property of the cells. Cells grown in the presence of trans–unsaturated fatty acids cannot transport so efficiently as compared to the cis-unsaturated fatty acid-grown cells except linolelaidic acid, a trans-transunsaturated fatty acid. Protein: phospholipid ratio of the membrane also varies significantly under such conditions. The affinity of L-phenylalanine transport carrier for the substrate changes remarkably in cells grown in the presence of different cis or trans-unsaturated fatty acids and indicate the possible role of membrane lipids in membrane assembly as well as regulation of the activity of L-phenylalanine transport system.

Effect of supplementation with exogenous fatty acid on the biological properties of a fatty acid requiring auxotroph of Salmonella typhimurium.

The effects of changes in fatty acid composition of the cell membrane on different biological functions of Salmonella typhimurium have been studied with the help of a temperature sensitive fatty acid auxotroph which cannot synthesise unsaturated fatty acids at high temperature. On being shifted to nonpermissive temperature the cells continue growing for another one and half to two generations. The rates of protein and DNA syntheses run parallel to the growth rate but the rate of RNA synthesis is reduced. Further, there is a gradual reduction in the rate of transport of exogenous uridine and thymidine into the soluble pool. The transport process can be restored by supplementing the growth medium with cis-unsaturated fatty acids but not trans-unsaturated ones although the growth of the cells is resumed by supplementation with either cis or trans-unsaturated fatty acids. However, supplementation with trans, trans-unsaturated fatty acids leads to only partial recovery of the transport process. The rate of oxygen uptake is also affected in cells grown in the presence of the trans-unsaturated fatty acids, elaidic acid and palmitelaidic acid. Analysis of cells grown under different fatty acid supplementation indicate that fatty acid composition of the cell membrane, especially the ratio of unsaturated to saturated fatty acids varies with temperature shift and supplementation of the growth media with fatty acids.