In this study we report that the activation of murine bone marrow-derived macrophages (BMDM) to the tumoricidal state by cisplatin is a Ca2+- and calmodulin-dependent process. Cisplatin induced an increase in [Ca2+]i in fura-2/AM-loaded BMDM in a cisplatin concentration-dependent manner, as evidenced by progressive increase in the relative fluorescence of the treated cells. Cisplatin-treated BMDM also showed a gradual increase in their ATP level in a cisplatin concentrationdependent manner. There was marked down-regulation of intracellular calcium level when the macrophages were pretreated with pertussis toxin or genistein and subsequently challenged with cisplatin; whereas macrophages treated with cholera toxin showed a slight increase in intracellular calcium, which was significantly upregulated upon cisplatin treatment. Calcium-modulating agents EGTA, nifedipine, and TMB-8, and the calmodulin antagonist W-7, inhibited cisplatin-induced tumoricidal activity of murine BMDM. Supernatants collected from macrophages treated with cisplatin and EGTA, nifedipine, TMB-8, or W-7 demonstrated decreased TNF and IL-1 activity in comparison to supernatants collected from macrophages treated with cisplatin alone.
In this study, the degree of in vitro cytotoxicity of anticancer drugs, including 5-fluorouracil, doxorubicin, cis-diamminedi-chloroplatinum, and mitomycin C, to vascular endothelial cells collected from the carotid artery of cows was evaluated by the MTT (3-(4, 5-dimeth-ylthiazol-2-yl)-3, 5-Biphenyl tetrazolium bromide) assay. The results indicated that the viability of vascular endothelial cells decreased with the addition of all of the above anti-cancer drugs, and a positive correlation was found between cytotoxicity and the drug concentration, as well as between cytotoxicity and the length of incubation with the anti-cancer drugs. The cytotoxicity of doxorubicin, cis-diamminedichloroplatinum, and mitomycin C became evident very rapidly and was stronger than that of 5-fluorouracil. The protective effect of prostaglandin E1 on the cytotoxicity caused by anti-cancer drugs was examined. The results also indicated that the addition of prostaglandin E1 inhibited the decrease in the viability of vascular endothelial cells which had been induced by 5-fluorouracil. These findings suggested that anti-cancer drugs cause endothelial cell injury and that prostaglandin E1 can protect this type of injury at least when induced by 5-fluorouracil.
The effects of feeding rats diets enriched in linoleic, α-linolenic, and eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) on plasma and liver cholesterol as well as on fecal excretion of neutral sterols and bile acids were examined. Male Sprague-Dawley rats were divided into four groups (n=7) and were fed isocaloric, isocholesterolemic, nutritionally adequate diets containing 20% (w/w) fat for four weeks. The diets contained high amounts of either beef tallow, sunflower oil, linseed oil or fish oil to achieve diets rich in saturated fats, linoleic acid, α-linolenic, or EPA plus DHA respectively. Rat feces were collected during the last three days of the fourth week and blood and livers were obtained at the end of the feeding period. Fecal sterol excretion (neutral sterols plus bile acids) was significantly higher in rats fed the linoleic and the α-linolenic acid-rich diets compared to those fed the saturated fatty acid-rich diet. Higher sterol excretion rate in the linoleic acid diet group was found to be primarily due to higher excretion of plant sterols, whereas cholesterol excretion as such was rather lower than that with the saturated fatty acid diet. Higher sterol excretion rate following the feeding of the α-linolenic acid-rich diet was mainly due to higher excretion of bile acids, specifically lithocholic and β-muricholic acid. Feeding of the linoleic acid-rich diet had no significant effect on bile acid excretion. EPA plus DHA, at the levels fed, had no effect on serum and liver cholesterol or on fecal excretion of total neutral sterol or bile acids, but significantly increased coprostanol excretion compared with that in the other groups. These data suggest that dietary linoleic acid reduces cholesterol excretion, which may partly be responsible for cholesterol accumulation in the hepatic tissue whereas n-3 fatty acids of plant (α-linolenic acid) and marine (EPA/DHA) origin increase fecal cholesterol excretion via different mechanisms, i.e., by increased conversion of cholesterol into bile acids.
It was reported earlier that administration of an acute dose of thioacetamide to rats produced changes in the rate of respiration, phosphate to oxygen ratio, and respiratory control ratio when either glutamate+malate or succinate were used as substrates (Padma and Setty, J. Clin. Biochem. Nutr., 22, 113-123). A significant decrease in the activities of electron transport chain enzymes was also observed. In the present study we report that administration of vitamin E prior to thioacetamide administration provided significant protection against the mitochondrial dysfunctions induced by thioacetamide. We speculate that the protective effect of vitamin E may be due to the ability of this vitamin to suppress elevated lipid peroxide levels in rats.
Oral submucous fibrosis (OSMF) is a chronic disease of obscure etiology affecting any part of the oral cavity. Several histologic and epidemiologic studies on this condition have been conducted, but the biochemical aspects have not yet been thoroughly explored. Hence we analyzed the clinically important enzymes in OSMF patients. They were divided into three groups according to the degree of severity of the disease. There was a significant increase in the activities of phosphatases, transaminases, aldolase, 5′-nucleotidase, and γ-glutamyl transpeptidase in OSMF patients as compared with normal subjects. The increase correlated well with the progression of the disease, being the highest in the advanced stage where patients had co-existing carcinoma. The results, it is hoped, will provide a means for classification of diseases at the structural and molecular level so as to highlight a causal nexus between clinical expression of the disease and altered structural and compositional changes in OSMF.
Bone mineral density (BMD) of lumbar spine (vertebrae 3, 4, and 5) as well as parathormone and estradiol (E2) levels were studied in two groups of postmenopausal women. The first group A, included 25 subjects who participated in exercise training. The second group B, comprised 15 subjects who did not participate in training. In group A, a significant rise in BMD, a significant decrease in parathormone level and no significant changes in E2 level were observed 6 months after the exercise training. In group B, no significant changes in parathormone level or BMD but a significant decrease in E2, were observed 6 months after starting the study.