S腺苷蛋氨酸对肝癌细胞中GADD45β基因的表达诱导及其机制研究

目的 初步明确肝癌细胞中特异性表达缺失的GADD45β基因近端启动子活性调控中心,并探讨S腺苷蛋氨酸对肝癌细胞HepG2中GADD45β表达的影响及可能机制.方法 以30～50个碱基的间隔,于体外人工合成GADD45β近端启动子序列(-618～-520),分别插入pGL3 basic荧光素表达质粒的荧光基因上游,以电穿孔法转染HepG2,根据启动子活性强度结合TRANSFAC数据库,分析可能存在的转录调节因子结合位点;实时荧光定量PCR比较S腺苷蛋氨酸作用前后HepG2细胞GADD45β表达,并在此基础上进一步比较S腺苷蛋氨酸对GADD45β启动子活性的诱导作用,探讨其可能作用机制,并为GADD45β近端启动子研究提供功能性证据.结果 GADD45β近端启动子中含有3个NF-kB转录调节因子与启动子结合位点(-602/-593、-581/-572、-537/-528);S腺苷蛋氨酸能明显诱导HepG2中GADD45β的表达,并呈现出剂量一效应的正相关关系,同时其能相应明显诱导NF-kB的启动子活性.结论 S腺苷蛋氨酸能明显诱导肝癌细胞中特异性缺失的GADD45β基因表达,增强转录调节因子NF-kB的活性水平是其可能的作用机制,该研究为S腺苷蛋氨酸的肝脏保护作用提供了新的实验依据.     

Terminal loop cutaneous ureterostomy in renal transplantation: an under utilized urinary diversion technique

PURPOSE: We evaluated the effectiveness of terminal loop cutaneous ureterostomy as a means of urinary drainage in kidney transplant recipients during a 20-year period. MATERIALS AND METHODS: Five cadaveric and 2 living related patients underwent kidney transplantation with terminal loop cutaneous ureterostomy between 1984 and 2004. These patients had no usable bladder or they were not suitable candidates for intermittent catheterization. RESULTS: Followup was 20 months to 17 years. One patient underwent stomal revision 5 months after renal transplantation. Current serum creatinine 4 years later was 166 mumol/l. The remaining 6 patients had no evidence of ureteral obstruction and rarely had bacteriuria or urinary tract infections. Four patients had a functioning allograft with normal serum creatinine. One patient died with a normally functioning allograft and the remaining patient lost his graft due to chronic rejection. No patient in this series lost the graft due to a urological cause. Overall outcomes included excellent allograft function with minimal infection or stomal stenotic complications. CONCLUSIONS: Terminal loop cutaneous ureterostomy is a simple, safe and alternative means of urinary diversion in patients with renal transplant and a defunctionalized lower urinary tract.     

Epidemiology of hepatitis B virus infection among young adults in Taiwan, China after public vaccination program

Background The public vaccination program of hepatitis B virus (HBV) was launched during 1984 in Taiwan, China. However, the long-lasting protective efficacy of HBV vaccination among adolescents older than 15 years of age was seldom recorded. Methods A seroepidemiological survey was conducted among 4575 first-year university students in Taiwan, China during 2000 to 2003, including the serological data of HBV by testing HBV surface antigen (HBsAg), surface antibody (anti-HBs), HBV core antibody (anti-HBc) and demographic information.Results HBsAg carrier rate among male university students born before the initiation of the HBV vaccination program decreased from 12.8% to 4.8% among those born after the vaccination program (P<0.001, χ(2) test for linear trend). Similarly, HBsAg carrier rate among female university students born before the initiation of the HBV vaccination program decreased from 8.1% to 2.7% among those born after the vaccination program (P<0.001, χ(2) test for linear trend). Both male and female students in eastern Taiwan had the highest HBsAg carrier rate compared with the other places. Using multiple logistic regression analysis, compared with students born after July 1984, the adjusted OR of HBsAg carrier rate decreased from 3.10 for students born before June 1981 to 1.56 for students born from July 1983 to June 1984 (95%CI 1.96－4.91, P<0.001; 95%CI 1.06－2.28, P=0.024; respectively).Conclusions Public vaccination provides long-lasting protection again HBV infection among the university students in Taiwan, China older than 18 years of age. There is a geographic variation of HBV infection among young adults in Taiwan, China.     

Effects of acetylcysteine and probucol on contrast medium-induced depression of intrinsic renal glutathione peroxidase activity in diabetic rats

BACKGROUND: Antioxidants such as N-acetylcysteine and probucol have been used to protect patients from contrast media-induced nephrotoxicity. The mechanisms underlying these protective effects are not well understood. We hypothesized that acetylcysteine and probucol alter the activity of endogenous antioxidant enzyme activity. METHODS: Four weeks after induction of diabetes with streptozotocin, diabetic and nondiabetic rats were divided into three groups. Group 1 rats did not receive any antioxidant agents. Group 2 rats were treated with acetylcysteine and group 3 rats with probucol for 1 week before injection of the contrast medium diatrizoate (DTZ). RESULTS: We found that diabetic rats had higher renal glutathione peroxidase (GPx) activity than normal rats. DTZ suppressed renal GPx activity significantly in both group 1 diabetic and normal rats. Interestingly, renal GPx activity in both diabetic and normal rats pretreated with acetylcysteine or probucol was not inhibited by DTZ. Renal superoxide dismutase (SOD) increased significantly in normal rats after DTZ injection, but not in diabetic rats. Finally, acetylcysteine or probucol did not significantly influence renal SOD. CONCLUSIONS: These findings suggest that the renal protective effects of acetylcysteine and probucol against contrast-induced oxidative stress and nephrotoxicity may be mediated by altering endogenous GPx activity.     

Cytokine expression in pediatric subperiosteal orbital abscesses

BACKGROUND: Cytokines have been shown to play a key role in infectious and inflammatory processes. The purpose of the study was to characterize the pattern of cytokine expression in subperiosteal orbital abscesses associated with pediatric orbital cellulitis. METHODS: All pediatric patients over a 5-month period who had orbital cellulitis and a subperiosteal abscess with an adjacent sinusitis requiring surgical drainage of the orbital abscess were given the opportunity to enroll in the study. A protein array membrane and a chemiluminescent detection system were used to identify the presence of 45 cytokines in the subperiosteal abscess fluid. RESULTS: Four abscesses were analyzed with the protein array membrane. Of the 45 cytokines studied for this report, interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist (ra), IL-6, tumor necrosis factor (TNF)-alpha, and TNF-beta were detected in all specimens. Additionally, IL-16, epidermal growth factor related protein, and soluble TNF receptor II were detected in 3 of the 4 specimens. INTERPRETATION: Pediatric orbital cellulitis with subperiosteal abscess is an inflammatory condition with a distinct pattern of cytokine expression. The detection of IL-1, IL-1 ra, IL-6, and TNF suggests that in the future these cytokines may play a role in monitoring disease activity or as potential targets for immunotherapy.     

Effect of dietary omega-3 and omega-6 fatty acid sources on PUVA-induced cutaneous toxicity and tumorigenesis in the hairless mouse

Because of concern about psoralen-induced phototoxicity and photocarcinogenesis, we investigated the effects of dietary lipids in a mouse model in which 8-methoxypsoralen (8-MOP) and UVA (PUVA) therapy has been shown to be carcinogenic. SKH-Hr-1 hairless albino mice were fed diets containing either omega-3 or omega-6 fatty-acid sources (menhaden oil and corn oil, respectively). After 2 weeks on the diets, the mice were treated topically with 8-MOP and then exposed to UVA (5 J/cm²). Mice receiving the omega-3 fatty-acid source exhibited a marked decrease in inflammatory response and a more rapid repair, as expressed both grossly and microscopically. In support of the latter response, i.e. repair, ornithine decarboxylase activity was about 20% greater in animals receiving the omega-3 fatty-acid source. The effects of the dietary fatty acid sources on PUVA tumorigenesis were examined in long-term studies in which animals were treated topically with 0.01% 8-MOP thrice weekly after which they were exposed to UVA (1 J/cm²). These studies indicated that a dietary lipid rich in omega-3 fatty acid and known to exhibit anti-inflammatory properties can markedly ameliorate the course of PUVA toxicity but does not impede the course of PUVA tumorigenesis     

Evidence that the retroviral DNA integration process triggers an ATR-dependent DNA damage response

Caffeine is an efficient inhibitor of cellular DNA repair, likely through its effects on ATM (ataxia telangiectasia mutated) and ATR (ATM and Rad3-related) kinases. Here, we show that caffeine treatment causes a dose-dependent reduction in the total amount of HIV-1 and avian sarcoma virus retroviral vector DNA that is joined to host DNA in the population of infected cells and also in the number of transduced cells. These changes were observed at caffeine concentrations that had little or no effect on overall cell growth, synthesis, and nuclear import of the viral DNA, or the activities of the viral integrase in vitro. Substantial reductions in the amount of host-viral-joined DNA in the infected population, and in the number of transductants, were also observed in the presence of a dominant-negative form of the ATR protein, ATRkd. After infection, a significant fraction of these cells undergoes cell death. In contrast, retroviral transduction is not impeded in ATM-deficient cells, and addition of caffeine leads to the same reduction that was observed in ATM-proficient cells. These results suggest that activity of the ATR kinase, but not the ATM kinase, is required for successful completion of the viral DNA integration process and/or survival of transduced cells. Components of the cellular DNA damage repair response may represent potential targets for antiretroviral drug development.     

A Placebo-Controlled Trial of Dextromethorphan as an Adjunct in Opioid-Dependent Patients Undergoing Methadone Maintenance Treatment

Background:

Low-dose dextromethorphan (DM) might have anti-inflammatory and neurotrophic effects mechanistically remote from an NMDA receptor. In a randomized, double-blind, controlled 12 week study, we investigated whether add-on dextromethorphan reduced cytokine levels and benefitted opioid-dependent patients undergoing methadone maintenance therapy (MMT).

Methods:

Patients were randomly assigned to a group: DM60 (60mg/day dextromethorphan; n = 65), DM120 (120mg/day dextromethorphan; n = 65), or placebo (n = 66). Primary outcomes were the methadone dose required, plasma morphine level, and retention in treatment. Plasma tumor necrosis factor (TNF)-α, C-reactive protein, interleukin (IL)-6, IL-8, transforming growth factor–β1, and brain-derived neurotrophic factor (BDNF) levels were examined during weeks 0, 1, 4, 8, and 12. Multiple linear regressions with generalized estimating equation methods were used to examine the therapeutic effect.

Results:

After 12 weeks, the DM60 group had significantly longer treatment retention and lower plasma morphine levels than did the placebo group. Plasma TNF-α was significantly decreased in the DM60 group compared to the placebo group. However, changes in plasma cytokine levels, BDNF levels, and the methadone dose required in the three groups were not significantly different.

Conclusions:

We provide evidence—decreased concomitant heroin use—of low-dose add-on DM’s efficacy for treating opioid-dependent patients undergoing MMT.