We have recently reported that melatonin protects against adriamycin-induced cardiomyopathy whose pathogenesis may involve free radicals and lipid peroxidation. Melatonin has also been shown to affect zinc turnover. Since zinc may act as an antioxidant, we investigated the role of zinc in the pathogenesis of adriamycin-induced cardiomyopathy as well as in the treatment of melatonin against this disorder. Sprague-Dawley rats were given adriamycin (cumulative dose, 15 mg/kg); melatonin (cumulative dose, 84 mg/kg); adriamycin plus melatonin; adriamycin plus probucol, another antioxidant (cumulative dose, 90 mg/kg); or vehicle alone, according to previously-used regimens. Cardioprotective effects of both antioxidants (melatonin and probucol) were confirmed by the parameters of fractional shortening, heart weight, heart/body weight ratio, ascites volume, and mortality. Adriamycin increased both the myocardial and plasma levels of thiobarbituric acid reactive substances (TBARS) and myocardial zinc levels, and decreased plasma zinc levels. The significant negative correlation observed between the myocardial and plasma zinc levels (r = 0.73, P < 0.01) among the samples of adriamycin-treated and control rats suggested an internal redistribution of zinc. Melatonin and probucol were equally effective in inhibiting the increase in myocardial TBARS as well as zinc levels, suggesting that myocardial zinc accumulation might be a protective response against adriamycin-induced oxidative stress. Melatonin also inhibited the adriamycin-induced decrease in plasma zinc levels; probucol was not as effective in doing so. In addition to melatonin's antioxidative effect, it may have the effect of maintaining the plasma zinc levels.
This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.
The aim of this study was to determine if fat absorption is better after pylorus-preserving pancreatoduodenectomy (PPPD) or duodenum-preserving pancreatic head resection (DPPHR) compared with that following pancreatoduodenectomy with gastrectomy (SPD), provided the patients have similar pancreatic exocrine function. Fat absorption was studied using the 13C-trioctanoin breath test in patients who were grouped according to the degree of fibrosis of the pancreatic remnant. The latter was judged by histologically measuring the fibrosis in a transectional wedge of resected pancreas. We evaluated 11 SPD cases, 25 PPPD cases, and 9 DPPHR cases. The 13C excretion rates and cumulative excretion values following DPPHR or PPPD were significantly better than those following SPD. The 13C excretion rates and cumulative values for the patients with > 30% fibrosis of the pancreas were lower than those in patients with < 30% pancreatic fibrosis, regardless of the surgical procedure. The cumulative value in the SPD group, however, was lower than that in the PPPD or DPPHR patients with < 30% pancreatic fibrosis. The results suggested that fat absorption following PPPD or DPPHR is superior to that after SPD in patients with the same fibrotic area of the pancreatic remnant and depends on the degree of fibrosis in the pancreatic remnant.
Weevaluated the influence of the levels of glycosylated hemoglobin (HbAlc) and fasting plasma glucose on the variation in low density lipoprotein (LDL) peak particle size in 210 subjects who were undergoing an annual check-up. Univariate analysis showed that LDLparticle size was significantly and positively correlated with high density lipoprotein (HDL) cholesterol levels, and was inversely correlated with the levels of total plasma cholesterol, triglycerides, fasting glucose, fasting insulin, HbAlc, and body mass index (BMI). Stepwise regression analysis selected four independent contributing variables that could affect LDLparticle size; triglyceride levels, HDL cholesterol levels, LDLcholesterol levels, and HbA1Clevels. Similar regression analysis performed for menand for normotensive subjects showedthat HbAlclevels also independently influenced LDLparticle size. The results indicate that HbAlc levels have a significant effect on LDLparticle size. This suggests that small LDLparticles would be present in subjects with non-insulindependent diabetes mellitus regardless of plasma lipid concentrations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.