A plasticized poly(vinyl chloride) surface was modified by azidation using sodium azide in the presence of a phase transfer catalyst in aqueous media. Subsequent to azidation, the surface was crosslinked using ultraviolet radiation. Contact angle measurements showed that the surface became hydrophilic on azidation whereas photoirradiation did not have any further effect on the hydrophilicity of the azidated surface. Control, azidated, and photocrosslinked surfaces were exposed to two strains of bacteria commonly implicated in device infection such as Staphylococcus aureus and Escherichia coli. Whereas the control and photocrosslinked surfaces showed no significant difference in bacterial adhesion, the azidated surface showed significantly reduced adhesion to both strains. Data obtained indicate that the presence of an intact azide function on the polymer surface is responsible for the reduced bacterial adherence and the surface hydrophobicity/hydrophilicity did not exert any effect in the present case. Although azides are known to be effective only against Gram-negative species, surprising was the observation that the azidated polymer surface was equally effective against a Gram-positive species such as S. aureus. Because sodium azide is routinely used as a preservative to prevent bacterial and fungal growth in many microbiology reagents and diagnostic kits, covalent binding of the azide onto a polymer surface or synthesizing azide containing polymers may be an interesting method to investigate in tackling the problem of bacterial adhesion and colonization of medical devices.

No abstract

The objective of the present study was to characterize the liver oil extracted from the deep sea shark, Echinorhinus brucus, caught from Central Indian Ocean and to evaluate its cytotoxic effect on neuroblastoma cell line (SHSY-5Y). Characterization of liver oil of Echinorhinus brucus revealed the presence of palmitic acid (15%), oleic acid (12%), stearic acid (8%), docosahexaenoic acid (DHA) (18%), and eicosapentaenoic acid (EPA) (16%). It was also found to be a good source of squalene (38.5%) and fat soluble vitamins such as A, D, and K (vitamin A: 17.08 mg/100 g of oil, vitamin D: 15.04 mg/100 g oil, and vitamin K: 11.45 mg/100 g oil). Since it was found to be rich in essential fatty acids, fat soluble vitamins, and squalene, it can be considered as better dietary supplement. The oil of Echinorhinus brucus also showed high in vitro cytotoxic effect against the human neuroblastoma cell line (SHSY-5Y) and the IC50 value laid between 35 and 45 ng.

No abstract

Tobacco induces oxidative stress in the alveolar epithelium and causes its damage. Retinoic acid (RA) has a cardinal role in alveolar cell growth, differentiation, and maturation. The aim of the study was to investigate the role of cell-cell interactions and whether RA could reverse the effect of tobacco extract on epithelial function as expressed by surfactant synthesis. For this, an in vitro model, which provides multiple cell type interactions, as seen in vivo, was used. We had used the major lung cell types, alveolar epithelial and mesenchymal cells represented by the cell lines A549 (human lung adenocarcinoma cell line), and human fetal lung fibroblast-1 (HFL-1) for developing the monoculture and co-culture systems and studied the effect of tobacco extract and retinoic acid. The effect of tobacco and retinoic acid both singly and in combination on proliferation and surfactant synthesis was analyzed. Retinoic acid induced proliferation and upregulated surfactant synthesis in monocultures and co-cultures. Tobacco extract at 100 μg/ml concentration decreased A549 proliferation and upregulated surfactant protein mRNA expression. In co-cultures treated with tobacco extract (100 μg/ml), retinoic acid (1 μM), regulated cell proliferation, and surfactant protein mRNA expression vis-à-vis the monoculture system. This clearly points to the fact that cell-cell interactions modulate the effect of additives or stimulants and help in assessing the in vivo combinatorial responses in vitro and that the retinoic acid effect is regenerative.