Effects of beta-carotene on cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats

The purpose of the present study was to evaluate the effects of beta-carotene on the cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats. Rats in the ethanol group were given an ethanol-containing liquid diet that provided 36 % of total energy as ethanol, while rats in the control group were fed an isoenergetic diet without ethanol. After 4 weeks, hepatocytes were taken out and cultured for 24 h. Hepatocytes from the rats in the control and ethanol groups were cultured in medium without (HC, HE) or with beta-carotene (HC+B, HE+B). The results showed that lactate dehydrogenase leakage was significantly increased in the HE compared with that in the HC group. However, lactate dehydrogenase leakage of the HE+B group was similar to that of the HC group. When compared with the HC group, activities of glutathione peroxidase and catalase in the HE group were significantly decreased by 54 and 31 %, respectively. Catalase activity in the HE+B group was significantly increased by 61 % compared with that in the HE group. However, activities of glutathione reductase and superoxide dismutase showed no difference among the groups. The level of glutathione in the HC+B and HE+B groups was significantly increased to 155 and 143 % compared with those in the HC and HE groups, respectively. The concentration of lipid peroxides showed no difference among the groups. The present results demonstrate that beta-carotene improved the cell viability of hepatocytes, and increased catalase activities and glutathione levels in hepatocytes from chronically ethanol-fed rats.     

A mechanistic study of cigarette smoke and cyclooxygenase-2 on proliferation of gastric cancer cells

Cigarette smoke has been shown to cause gastric cancer. Overexpression of cyclooxygenase-2 (COX-2) is a common characteristic in gastric malignancy. The present study aimed to explore the correlation between cigarette smoke and COX-2 in the promotion of tumorigenesis in human gastric cancer cells (AGS). We further studied the action of COX-2 on other proto-oncogenes on gastric tumor growth. Results showed that chloroform extract (CE) and ethanol extract (EE) from cigarette smoke dose-dependently stimulated gastric cancer cell proliferation, which was accompanied with an activation of ornithine decarboxylase (ODC) activity, COX-2, and c-myc expressions. Both antisense of c-myc and alpha-difluoromethylornithine (DFMO, specific ODC inhibitor) inhibited cell proliferation without affecting COX-2 expression in response to cigarette smoke extracts (CSE). However, selective COX-2 inhibitor (SC-236) not only blocked the proliferative activity but also the ODC activity and c-myc protein expression by CSE in gastric cancer cells. Further, supplementation of exogenous prostaglandin (PG) E(2) reversed all the inhibitory actions of SC-236. Our results underline the importance of COX-2 in the cancer-promoting effect of CSE and its modulation on its downstream growth-related genes, such as c-myc and ODC in cancer cell proliferation. These results reveal that CSE-induced gastric carcinogenesis is via the COX-2/c-myc/ODC and PGE(2)-dependent pathway. Hence, selective COX-2 inhibitor could be an effective therapeutic agent for gastric cancer in smokers.     

Constitutional activation of IL-6-mediated JAK/STAT pathway through hypermethylation of SOCS-1 in human gastric cancer cell line

The interleukin-mediated Janus kinase (JAK)/STAT pathway plays a crucial role in carcinogenesis. Recently, increased STAT3 activity was found in hepatocellular carcinoma and multiple myeloma in which there was silencing of SOCS-1 (suppressor of cytokine signalling-1) by gene promoter hypermethylation. We investigated the expression level of interleukin-6 (IL-6) and SOCS-1 in gastric cancer cell lines. Expression of SOCS-1 correlated with IL-6 level in most of the cell lines, except for AGS cells in which SOCS-1 was absent despite a high level of IL-6 production. Methylation analysis by methylation-specific polymerase chain reaction and bisulphite sequencing revealed that CpG island of SOCS-1 was densely methylated in AGS cells. Demethylation treatment by 5'aza-deoxycytidine restored SOCS-1 expression and also suppressed constitutive STAT3 phosphorylation in AGS cells. Moreover, methylation of SOCS-1 was detected in 27.5% (11 of 40) of primary gastric tumours samples, 10% (one of 10) of adjacent noncancer tissues but not in any (zero of nine) normal gastric mucosa. Methylation of SOCS-1 also correlated with the loss of mRNA expression in some primary gastric cancers. In conclusion, this is the first report to demonstrate that hypermethylation of SOCS-1 led to gene silencing in gastric cancer cell line and primary tumour samples. Downregulation of SOCS-1 cooperates with IL-6 in the activation of JAK/STAT pathway in gastric cancer.     

Bacteria-induced intestinal cancer in mice with disrupted Gpx1 and Gpx2 genes

Two glutathione peroxidase (GPX) isozymes, GPX-1 and GPX-2 (GPX-GI), are the major enzymes that reduce hydroperoxides in intestinal epithelium. We have previously demonstrated that targeted disruption of both the Gpx1 and Gpx2 genes (GPX-DKO) results in a high incidence of ileocolitis in mice raised under conventional conditions, which include the harboring of Helicobacter species [non-specific-pathogen-free (non-SPF) conditions]. In this study, we have characterized GPX-DKO mice that have microflora-associated intestinal cancers, which are correlated with increased intestinal pathology/inflammation. We found that GPX-DKO mice raised under germ-free conditions have virtually no pathology or tumors. After colonizing germ-free mice with commensal microflora without any known pathogens (SPF), <9% of GPX-DKO mice develop tumors in the ileum or the colon. However, about one-fourth of GPX-DKO mice raised under non-SPF conditions from birth or transferred from SPF conditions at weaning have predominantly ileal tumors. Nearly 30% of tumors are cancerous; most are invasive adenocarcinomas and a few signet-ring cell carcinomas. On the basis of these results, we conclude that GPX-DKO mice are highly susceptible to bacteria-associated inflammation and cancer. The sensitivity exhibited in these mice suggests that peroxidative stress plays an important role in ileal and colonic pathology and inflammation, which can lead to tumorigenesis.     

Combination of alpha-interferon with lamivudine reduces viral breakthrough during long-term therapy

BACKGROUND AND AIM: Viral breakthrough is frequently encountered during long-term lamivudine therapy, mostly associated with YMDD mutants. In this study, we investigated the effects of alpha-interferon (IFN-alpha) combined with lamivudine on the occurrence of viral breakthrough during long-term lamivudine therapy. METHODS: Eighty-three patients with biopsy-proven chronic hepatitis B were randomly allocated to a combination of lamivudine and IFN-alpha (LAM/IFN; n = 41) or lamivudine only (LAM; n = 42), and then followed up for >12 months. We calculated the cumulative rate of undetectable serum HBV-DNA and hepatitis B e antigen (HBeAg) loss, as well as the cumulative occurrence rate of viral breakthrough. We also evaluated the relationship between YMDD mutants and the occurrence of viral breakthrough. RESULTS: There was no difference in cumulative rates of undetectable serum HBV-DNA (100%vs 100% at 24 months, P = 0.13) and cumulative rates of serum HBeAg loss between the LAM/IFN group and the LAM group (49%, 61% and 67%vs 31%, 39% and 42%, respectively, at 12, 24 and 36 months; P = 0.07). The cumulative occurrence rate of viral breakthrough, however, was significantly lower in the LAM/IFN group compared with the LAM group (5%, 20% and 30%vs 10%, 55% and 58%, respectively, at 12, 24 and 36 months; P = 0.006). From the patients with viral breakthrough, YMDD mutants were detected in 82% (18 of 22) of the LAM group in contrast with 56% (five of nine) of the LAM/IFN group in their sera. CONCLUSION: IFN-alpha combined with lamivudine may reduce viral breakthrough during long-term lamivudine therapy, probably by suppressing the appearance of YMDD mutants.     

Clinical diagnosis and assessment of severity of confirmed dengue infections in Vietnamese children: is the world health organization classification system helpful?

Classification of dengue using the current World Health Organization (WHO) system is not straightforward. In a large prospective study of pediatric dengue, no clinical or basic laboratory parameters clearly differentiated between children with and without dengue, although petechiae and hepatomegaly were independently associated with the diagnosis. Among the 712 dengue-infected children there was considerable overlap in the major clinical features. Mucosal bleeding was observed with equal frequency in those with dengue fever and dengue hemorrhagic fever (DHF), and petechiae, thrombocytopenia, and the tourniquet test differentiated poorly between the two diagnostic categories. Fifty-seven (18%) of 310 with shock did not fulfill all four criteria considered necessary for a diagnosis of DHF by the WHO, but use of the WHO provisional classification scheme resulted in considerable over-inflation of the DHF figures. If two separate entities truly exist rather than a continuous spectrum of disease, it is essential that some measure of capillary leak is included in any classification system, with less emphasis on bleeding and a specific platelet count.     

Characteristic clinical features of hepatocellular carcinoma associated with Budd-Chiari syndrome: evidence of different carcinogenic process from hepatitis B virus-associated hepatocellular carcinoma

OBJECTIVE: Budd-Chiari syndrome (BCS) is a known risk factor for hepatocellular carcinoma (HCC). Considering the pathophysiological mechanism of BCS, BCS-associated HCC may have a different carcinogenic process to hepatitis B virus (HBV)-associated HCC, resulting in different characteristic clinical features. METHODS: The clinical, radiological and histopathological characteristics of 15 HCCs associated with BCS were analysed and compared with 211 HBV-associated HCCs. RESULTS: HCC associated with BCS showed a female predominance in contrast to a male predominance in HCC associated with HBV infection. Child classes of BCS-associated HCC patients were not different from the classes of HBV-associated HCC. BCS tended to be associated with the single nodular type of HCC. Only one BCS-associated HCC patient had portal vein invasion at the time of diagnosis, compared with 96 patients with HBV-associated HCC. No HCC patients with BCS showed biliary invasion, compared with 47 HBV-associated HCC patients. The median survival period of HCC patients associated with BCS was 58 months, which was much longer than the median survival period of 10 months in HBV-associated HCC. All of the three BCS-associated HCCs available for histological examination were well differentiated. CONCLUSIONS: Patients with HCC associated with BCS seemed to survive for much longer periods than those with HBV due to the low invasiveness of the tumour. Such unique clinical features may be evidence of different carcinogenic processes in BCS-associated and HBV-associated HCC.     

Issues in the management of endocarditis caused by resistant gram-positive organisms

Most cases of infective endocarditis (IE) are caused by gram-positive bacteria such as enterococci, streptococci, and staphylococci. Increasing resistance among these organisms has eroded the utility of mainstay antibiotics and complicated the management of this difficult-to-treat infection. Clinical experience with newer gram-positive antibiotics to treat IE is limited.     

Ankle-brachial pressure index measured using an automated oscillometric method as a predictor of the severity of coronary atherosclerosis in patients with coronary artery disease

Ankle-brachial pressure index (ABI) measured using a conventional Doppler method is an independent predictor of the number of coronary vessels affected in coronary artery disease (CAD). Recently, a new clinical device has been developed to measure ABI using an oscillometric method. It is unclear whether ABI measured using this device is a significant predictor of the severity of coronary atherosclerosis. We retrospectively included 87 patients from our outpatient clinic who had ever undergone coronary angiography. ABI was determined in all subjects using the new ABI-form device. The lower value of ABI in either limb was used for analysis. We divided our subjects into two groups, with either ABI less than 0.9 or at least 0.9, and compared basal characteristics between groups. We analyzed the relationship between ABI and the severity of CAD. In addition, we calculated the sensitivity, specificity, and positive and negative predictive values of ABI less than 0.9 in predicting multivessel (two-vessel + three-vessel) involvement in our patients. There were 15 patients with ABI less than 0.9 and 72 with ABI at least 0.9. Patients with ABI less than 0.9 were older and had higher plasma levels of uric acid. The prevalence of diabetes mellitus, hypertension, smoking, and diuretic use was significantly higher in patients with ABI less than 0.9. In addition, the group with ABI less than 0.9 had a lower prevalence of one-vessel CAD and higher prevalence of three-vessel or multivessel CAD. The sensitivity, specificity, and positive and negative predictive values of ABI less than 0.9 in predicting multivessel CAD were 22%, 96%, 93%, and 34%, respectively. In conclusion, ABI measured using the automated oscillometric method can be used to predict the severity of coronary atherosclerosis in patients with CAD.     

Treatment of xanthoma disseminatum with cyclophosphamide

Xanthoma disseminatum is a rare non-Langerhans cell (class II) histiocytosis, which is often resistant to treatment. We describe an illustrative case with extensive mucocutaneous, ocular, laryngeal, pituitary and central nervous system involvement, which responded to treatment with cyclophosphamide. The presentation, course and treatment of the condition are reviewed. Many of the non-Langerhans cell histiocytoses represent a spectrum of diseases of dermal dendrocytes ranging from self-limiting and benign conditions to multisystem progressive diseases that respond poorly to treatment and severely impair quality of life. We suggest that chemotherapy should be considered at an early stage in the more aggressive subtypes of non-Langerhans cell histiocytoses.