[Activation of renal outer medullary potassium channel in the renal distal convoluted tubule by high potassium diet].

Renal outer medullary potassium (ROMK) channel is an important K+ excretion channel in the body, and K+ secreted by the ROMK channels is most or all source of urinary potassium. Previous studies focused on the ROMK channels of thick ascending limb (TAL) and collecting duct (CD), while there were few studies on the involvement of ROMK channels of the late distal convoluted tubule (DCT2) in K+ excretion. The purpose of the present study was mainly to record the ROMK channels current in renal DCT2 and observe the effect of high potassium diet on the ROMK channels by using single channel and whole-cell patch-clamp techniques. The results showed that a small conductance channel current with a conductance of 39 pS could be recorded in the apical membrane of renal DCT2, and it could be blocked by Tertiapin-Q (TPNQ), a ROMK channel inhibitor. The high potassium diet significantly increased the probability of ROMK channel current occurrence in the apical membrane of renal DCT2, and enhanced the activity of ROMK channel, compared to normal potassium diet (P < 0.01). Western blot results also demonstrated that the high potassium diet significantly up-regulated the protein expression levels of ROMK channels and epithelial sodium channel (ENaC), and down-regulated the protein expression level of Na+-Cl- cotransporter (NCC). Moreover, the high potassium diet significantly increased urinary potassium excretion. These results suggest that the high potassium diet may activate the ROMK channels in the apical membrane of renal DCT2 and increase the urinary potassium excretion by up-regulating the expression of renal ROMK channels.

The association of three promoter polymorphisms in interleukin-10 gene with the risk for colorectal cancer and hepatocellular carcinoma: A meta-analysis.

Mounting evidence supports a potent inhibitory role of interleukin-10 (IL-10) in tumor carcinogenesis, angiogenesis and metastasis. This meta-analysis was designed to examine the association of three promoter polymorphisms (-592C > A, -819C > T and -1082G > A) in IL-10 gene with the risk for colorectal cancer and hepatocellular carcinoma. Qualification assessment and data collection were completed by two authors independently. The random-effects model using the DerSimonian and Laird method was fitted by the STATA software. Twenty-five articles involving 5933 cases and 9724 controls were meta-analyzed. Overall comparisons of the mutant alleles (-592A, -819T and -1082A) of three promoter polymorphisms with alternative wild alleles failed to reveal any statistical significance for both colorectal cancer and hepatocellular carcinoma (P > 0.05), and the likelihood of heterogeneity was low (I(2) < 50%). For -592C > A polymorphism, a significant risk for colorectal cancer was identified when analysis was restricted to East Asians (odds ratio or OR = 1.41, 95% confidence interval or CI: 1.18-1.68, P < 0.001) and retrospective studies (OR = 1.23, 95% CI: 1.09-1.39, P = 0.001). As weighed by the Egger's test and the fill-and-trim method, there was a low probability of publication bias for all studied polymorphisms. Our findings collectively suggest that the -592C > A polymorphism in IL-10 gene might be a susceptibility locus for colorectal cancer in East Asians.

The association of six non-synonymous variants in three DNA repair genes with hepatocellular carcinoma risk: a meta-analysis.

Hepatocellular carcinoma is a complex polygenic disease. Despite the huge advances in genetic epidemiology, it still remains a challenge to unveil the genetic architecture of hepatocellular carcinoma. We, therefore, decided to meta-analytically assess the association of six non-synonymous coding variants from XRCC1, XRCC3 and XPD genes with hepatocellular carcinoma risk by pooling the results of 20 English articles. This meta-analysis was conducted according to the PRISMA statement, and data collection was independently completed in duplicate. In overall analyses, the minor alleles of four variants, Arg280His (odds ratio, 95% confidence interval, P: 1.37, 1.13-1.66, 0.001), Thr241Met (1.93, 1.17-3.20, 0.011), Asp312Asn (1.22, 1.08-1.38, 0.001) and Lys751Gln (1.42, 1.02-1.97, 0.038), were associated with the significant risk for hepatocellular carcinoma. There were low probabilities of publication bias for all variants. Subgroup analyses revealed significant association of XRCC1 gene Arg399Gln with hepatocellular carcinoma in Chinese especially from south China (odds ratio, 95% confidence interval, P: 1.57, 1.16-2.14, 0.004), in larger studies (1.48, 1.11-1.98, 0.007) and in studies with population-based controls (1.33, 1.06-1.68, 0.016). Taken together, our findings demonstrated that XPD gene Asp312Asn and XRCC1 gene Arg399Gln might be candidate susceptibility loci for hepatocellular carcinoma. Considering the ubiquity of genetic heterogeneity, further validation in a broad range of ethnic populations is warranted.

[Study on protective effect of vitamin E for ovarian grandlose cells and its mechanism in aged rats].

AIM: To observe the effect of vitamin E (VE) on ovarian apoptosis-related protein Bcl-2 and Bax and its impact on antioxidant capacity in aged female rats and to study the senility-delaying effect and mechanism of VE on ovary. METHODS: Natural aging female rats were given different doses of exogenous VE. Then apoptosis regulatory protein Bcl-2, Bax expression in ovarian grandlose cells were detected by using immunohistochemical methods and Western blot. The contents of serum total superoxide dismutase (SOD) activity and malondialdehyde (MDA) were detected by using biochemical methods. RESULTS: Contrasted with adult control group, the level of Bcl-2 expression in Senile control group was lower and the level of Bax expression was higher (P < 0.01), Serum SOD activity decreased and the level of MDA significantly increased (P < 0.01). Contrasted with senile control group, the level of Bcl-2 expression increased in VE group, the level of Bax expression decreased (P < 0.05), the level of MDA expression significantly decreased (P < 0.01). CONCLUSION: VE can regulate apoptosis-related protein Bcl-2, Bax expression and confront free radical damage which contribute to a protective effect for ovarian grandiose cells.

[Effects of vitamin E on expression of PS-1 and production of Abeta in the hippocampus of female senile rats].

AIM: To observe the expression of Presenilin-1 (PS-1) and production of amyloid beta-protein (Abeta) in hippocampus of female senile rats and to investigate the effect of vitamin E(VE) on preventing Alzheimer's disease after menopause. METHODS: The animal model was established using female senile rats. Experimental groups (n=8) were respectively given different doses of VE(5 mg/kg, 15 mg/kg, 60 mg/kg) per day. The expression of PS-1 in hippocampus was detected by immunohistochemistry, the level of Abeta in hippocampus was measured by Radioimmunoassay, and neuronal ultrastructure in hippocampal DG area was observed using transmission electron microscope. RESULTS: The expression of PS-1 in rat hippocampus of senile control group was stronger than that of adult control group. PS-1 expressed weakly in three medication groups along with augmentation of dosage. The levels of Abeta were found to correlate statistically with the expression of PS-1. The content of Abeta in VE groups was significantly decreased compared to that in senile control group (P < 0.01). There were some changes in the neuronal ultrastructure of senile rats. Neurons were gradually recovered in VE groups. CONCLUSION: VE may depress the production of Abeta by regulating the expression of PS-1, reducing neuronal injuries. VE may play a role in neuronal protection.