Influence of p-coumaric acid on doxorubicin-induced oxidative stress in rat's heart.

The therapeutic value of doxorubicin (DOX) as anticancer antibiotic is limited by its cardiotoxicity. The implication of natural phenolic acids in the prevention of many pathologic diseases has been reported. Herein, the ability of p-coumaric (PC) acid, a member of phenolic acids, to protect rat's heart against DOX-induced oxidative stress was investigated. Three main groups of albino rats were used; DOX, PC, and PC plus DOX-receiving animals. Corresponding control animals were also used. DOX was administered i.p. in a single dose of 15mgkg(-1). PC alone, in a dose of 100mgkg(-1), was orally administered for five consecutive days. In PC/DOX group, rats received PC 5 days prior to DOX. DOX-induced high serum levels of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK), were reduced significantly by PC administration, compared to DOX-receiving rats. Pretreatment with PC ameliorated the cardiac content of glutathione (GSH), and superoxide dismutase (SOD) & catalase (CAT) activities, compared to DOX-receiving rats. On the other hand, accumulation of cardiac content of MDA significantly decreased following PC pretreatment, compared to DOX-treated rats. The data presented here indicate that PC protects rats hearts against DOX-induced oxidative stress in the heart. It may be worthy to consider the usefulness of PC as adjuvant therapy in cancer management.

Studies on the structures and antigenic properties of rabies virus glycoprotein analogues produced in yeast cells.

We investigated two forms (designated as yGI and yGII) of rabies virus glycoprotein (G) analogues produced in the G cDNA-transfected yeast cells. Molecular weights of yGI and yGII were estimated as 66 and 56 kDa, respectively, according to their relative mobility in SDS-PAGE. Although being produced in large amounts, yGI was present mostly in insoluble forms and hardly extractable with non-ionic detergents. The yGI reacted with polyclonal anti-G antibodies, but did not react with our conformational epitope-specific anti-G monoclonal antibodies (G-MAbs). No protective immunity was induced by yGI in guinea pigs nor in mice. On the other hand, yGII was Triton-soluble, but was only small in amount (at most 1% of total G proteins) and was shown to lack the cytoplasmic domain. The yGII, however, reacted with the G-MAbs and induced protective immunity in guinea pigs as well. When the G-cDNA was expressed in animal cells in culture, a single form (about 66 kDa) of G protein was produced, which displayed similar behaviors as seen in its reactivity with the MAbs and intracellular distribution as seen in the virus-infected cells. These results suggest that most G protein molecules were not processed normally in yeast cells, resulting in abnormal folding and multimer formation, while only a small fraction were occasionally folded normally to have conformational epitopes but were mostly deprived of the C-terminal portion.