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Oxidative stress is a main factor in the pathogenesis of severe acute pancreatitis (SAP). The ability of zinc (Zn) to retard oxidative processes has been recognized for many years. This study aims to examine the levels of free oxygen radicals and antioxidant enzyme in SAP rats and know the effect of Zn supplementation on free oxygen radicals and antioxidant system in rats with SAP. Forty-five male Wistar rats were divided into three groups-the SAP group (n=15), the Zn-treated group (n=15), and the controlled group (n=15). For the SAP group, sodium taurocholate is injected into the pancreatic duct to induce SAP; for the Zn-treated group, Zn (5 mg/kg) is subcutaneously injected immediately after injection of 5% sodium taurocholate. Firstly, the activity of erythrocyte glutathione peroxidase (GSH-Px), erythrocyte superoxide dismutase (SOD), and the content of plasma malondialdehyde (MDA), which are the toxic products of oxidative stress, is measured. Secondly, the levels of free oxygen radicals in the liver and kidney are detected. The result showed that the activity of GSH-Px and SOD was lower in the SAP group than that in the controlled group, although the content of plasma MDA increased. However, the activity of SOD and GSH-Px in the Zn-treated group was not significantly decreased after comparing with the controlled group; in the mean time, the content of MDA was not significantly increased either. Moreover, the content of free radical in liver and kidney was higher in the SAP group compared with the controlled group, but the content of free radical in the Zn-treated group was not higher than that in the controlled group (p>0.05). All of the above indicated that Zn may recover the activity of free radical-scavenging enzymes and decrease the content of free radical for the SAP group rats. In conclusion, the content of free radical increase may be one of the reasons that SAP rats are injured, and it is possible for Zn to be used to treat SAP through scavenging free radical and increasing the activity of SOD and GSH-Px of erythrocyte.

To investigate the effects of dietary copper (Cu) on fish growth, digestive and absorptive enzyme activities, and antioxidant status in the hepatopancreas and intestine, young grass carp (Ctenopharyngodon idella) (282±2.8 g) were fed six diets containing 0.74 (basal diet), 2.26, 3.75, 5.25, 6.70, and 8.33 mg Cu /kg diet for 8 weeks. Results showed that percentage weight gain (PWG) and feed intake were increased with dietary Cu levels up to 3.75 mg/kg diet. In addition, the positive effects of dietary Cu at a level 3.75 or 5.25 mg/kg diet on trypsin, chymotrypsin, and lipase activities in the hepatopancreas and of Na(+), K(+)-ATPase, alkaline phosphatase, creatine kinase, and γ-glutamyl transpeptidase activities in three intestine segments produced significantly (P<0.05) better feed efficiency (FE). However, amylase activity in the hepatopancreas was decreased by dietary Cu levels up to 3.75 mg/kg diet (P<0.05). In addition, dietary Cu at 3.75 or 5.25 mg/kg diet decreased malondialdehyde and protein carbonyl content partly by significantly (P<0.05) increasing the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and glutathione content in the hepatopancreas and intestine. Collectively, dietary Cu improved growth and digestive and absorptive capacity and decreased lipid peroxidation and protein oxidation partly by enhancing antioxidant defense in the hepatopancreas and intestine. The dietary Cu requirement for PWG, plasma ceruloplasmin activity, and FE of young grass carp (282-688 g) were 4.78, 4.95, and 4.70 mg/kg diet, respectively.

This paper presents a systematic review of the literature concerning fluoride that was carried out to investigate whether fluoride exposure increases the risk of low intelligence quotient (IQ) in China over the past 20 years. MEDLINE, SCI, and CNKI search were organized for all documents published, in English and Chinese, between 1988 and 2008 using the following keywords: fluorosis, fluoride, intelligence, and IQ. Further search was undertaken in the website www.fluorideresearch.org because this is a professional website concerning research on fluoride. Sixteen case-control studies that assessed the development of low IQ in children who had been exposed to fluoride earlier in their life were included in this review. A qualitative review of the studies found a consistent and strong association between the exposure to fluoride and low IQ. The meta-analyses of the case-control studies estimated that the odds ratio of IQ in endemic fluoride areas compared with nonfluoride areas or slight fluoride areas. The summarized weighted mean difference is -4.97 (95%confidence interval [CI] = -5.58 to -4.36; p < 0.01) using a fixed-effect model and -5.03 (95%CI = -6.51 to 3.55; p < 0.01) using a random-effect model, which means that children who live in a fluorosis area have five times higher odds of developing low IQ than those who live in a nonfluorosis area or a slight fluorosis area.