Oxidative DNA damage in peripheral leukocytes and its association with expression and polymorphisms of hOGG_1:A study of adolescents in a high risk region for hepatocellular carcinoma in China

AIM: To study the oxidative DNA damage to adolescents of hepatocellular carcinoma (HCC) families in Guangxi Zhuang Autonomous Region, China.METHODS: Peripheral leukocytes' DNA 7, 8-dihydro-8-oxoguanine (8-oxoG) and repair enzyme hOGG1 were quantified by flow-cytometry. hOGG1-Cys326Ser single nucleotide polymorphism (SNP) was distinguished by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) assay.RESULTS: There was a positive correlation between 8-oxoG and repair enzyme hOGG1 expression (P＜0.001). HCC children (n=21) in Fusui county had a higher level of hOGG1(P＜0.01) and a lower level of 8-oxoG (P＜0.05) than the controls (n=63) in Nanning city. Children in Nanning exposed to passive-smoking had a higher hOGG1 expression (P＜0.05)than the non-exposers. 8-oxoG and hOGG1 were negatively correlated with body mass index, while hOGG1 was positively correlated with age. There was a peak of 8-oxoG level nearby the 12 year point. Individuals with the hOGG1 326Ser allele had a significantly marginal higher concentration of leukocyte 8-oxoG level than hOGG1 326Cys allele.CONCLUSION: This is the first report using flow-cytometry to simultaneously quantify both the DNA oxidative damage and its repairing enzyme hOGG1. The results provide new insights towards a better understanding of the mechanisms of oxidative stress in a population highly susceptible to hepatocarcinogenesis.

Intestinal perforation after combined liver-kidney transplantation for a case of congenital polycystic disease

AIM: To highlight the intestinal perforation (IP), an uncommon and catastrophic complication after combined liver-kidney transplantation.METHODS: Combined liver-kidney transplantation (LKTx) with left kidney excision and a cyst fenestration procedure on the right kidney were performed on a case of 46-year-old female with congenital polycystic disease (CPCD).RESULTS: Two sites of IP were noted 40-50 cm proximal to ileocecal area during emergent laparotomy 10 d postoperatively.Despite aggressive surgical and medical management,disease progressed toward a fatal outcome due to sepsis and multiple organ failure 11 d later.CONCLUSION: Long duration of operation without venovenous bypass, overdose of steroid together with postoperative volume excess may all contribute to the risk of idiopathic multiple IPs. Microbiology and pathology inspections suggested that the infected cyst of the fenestrated kidney might be one reason for the fatal intra-peritoneal infection. Thus for the CPCD patients who seem to be very susceptible to infectious complications, any sign of suspected renal-infection found before or during LKTx is indication for the excision of original kidney. And the intensity of immunosuppression therapy should be controlled cautiously.

Potent and specific inhibition of SARS-CoV antigen expression by RNA interference

Background Severe acute respiratory syndrome (SARS) is an infectious disease caused by SARS-CoV. There are no effective antiviral drugs for SARS although the epidemic of SARS was controlled. The aim of this study was to develop an RNAi (RNA interference) approach that specifically targeted the N gene sequence of severe acute respiratory syndrome associated coronavirus (SARS-CoV) by synthesizing short hairpin RNA (shRNA) in vivo , and to assess the inhibitory effect of this shRNA on SARS-CoV N antigen expression. Methods The eukaryotic expression plasmid pEGFP-C1-N, containing SARS-CoV N gene, was co-transfected into 293 cells with either the RNAi plasmid pshRNA-N or unrelated control plasmid pshRNA-HBV-C4. At 24, 48 and 72 hours post transfection, the green fluorescence was observed through a fluorescence microscope. The RNA levels of SARS-CoV N were determined by reverse transcription polymerase chain reaction (RT-PCR). The expression of Green Fluorescent Protein (GFP) and protein N were detected using Western blot.Results The vector, pshRNA-N expressing shRNA which targeted the N gene of SARS-CoV, was successfully constructed. The introduction of RNAi plasmid efficiently and specifically inhibited the synthesis of protein N. RT-PCR showed that RNAs of N gene were clearly reduced when the pEGFP-C1-N was cotransfected with pshRNA-N, whereas the control vector did not exhibit inhibitory effect on N gene transcription.Conclusions Our results demonstrate that RNAi mediated silencing of SARS-CoV gene could effectively inhibit expression of SARS-CoV antigen, hence RNAi based strategy should be further explored as a more efficacious antiviral therapy of SARS-CoV infection.