Permeability enhancement of the KcsA channel under radiation of a terahertz wave.

Potassium ion channels are essential elements in cellular electrical excitability and help maintain a resting potential in nonexcitable cells. Their universality is based on a unique combination of strong selectivity for K^{+} ions and near-diffusion-limited permeation efficiency. Understanding how the channel regulates the ion conduction would be instructive to the treatment of ion channelopathies. In this work, by means of molecular dynamics simulations, we demonstrate the significantly enhanced permeation of KcsA channel in reaction to an external terahertz wave, due to the effective response of the K^{+} ions in the selectivity filter regions of the channel. Compared to the case without external terahertz wave, a fourfold increase in the ion current through the channel is found.

Safety validation of decision trees for hepatocellular carcinoma.

AIM: To evaluate a different decision tree for safe liver resection and verify its efficiency. METHODS: A total of 2457 patients underwent hepatic resection between January 2004 and December 2010 at the Chinese PLA General Hospital, and 634 hepatocellular carcinoma (HCC) patients were eligible for the final analyses. Post-hepatectomy liver failure (PHLF) was identified by the association of prothrombin time < 50% and serum bilirubin > 50 µmol/L (the "50-50" criteria), which were assessed at day 5 postoperatively or later. The Swiss-Clavien decision tree, Tokyo University-Makuuchi decision tree, and Chinese consensus decision tree were adopted to divide patients into two groups based on those decision trees in sequence, and the PHLF rates were recorded. RESULTS: The overall mortality and PHLF rate were 0.16% and 3.0%. A total of 19 patients experienced PHLF. The numbers of patients to whom the Swiss-Clavien, Tokyo University-Makuuchi, and Chinese consensus decision trees were applied were 581, 573, and 622, and the PHLF rates were 2.75%, 2.62%, and 2.73%, respectively. Significantly more cases satisfied the Chinese consensus decision tree than the Swiss-Clavien decision tree and Tokyo University-Makuuchi decision tree (P < 0.01，P < 0.01); nevertheless, the latter two shared no difference (P = 0.147). The PHLF rate exhibited no significant difference with respect to the three decision trees. CONCLUSION: The Chinese consensus decision tree expands the indications for hepatic resection for HCC patients and does not increase the PHLF rate compared to the Swiss-Clavien and Tokyo University-Makuuchi decision trees. It would be a safe and effective algorithm for hepatectomy in patients with hepatocellular carcinoma.

MicroRNA-107 promotes proliferation of gastric cancer cells by targeting cyclin dependent kinase 8.

BACKGROUND: The biological processes and molecular mechanisms underlying miR-107 remain unclear in gastric cancer(GC). In this study, we aimed to investigate the expression, biological functions and mechanisms of miR-107 in GC. METHODS: Quantitative real-time RT-PCR was used to test miR-107 expression. MTT and colony formation assays were conducted to explore the potential function of miR-107 in human GC cell line SGC7901. The target gene was determined by bioinformatic algorithms, dual luciferase reporter assay, RT-PCR and Western blot. RESULTS: Expression of miR-107 was significantly elevated in GC cell line than that in gastric epithelial cell line(p = 0.012). We found that miR-107 inhibitor transfection significantly decreased the proliferation of GC cell line, and clone formation rate of miR-107 inhibitor transfected group was significantly lower than that of control group. Luciferase assays using a reporter carrying a putative miR-107 target site in the 3'untranslated region (3'-UTR) of cyclin dependent kinase 8 (CDK8) revealed that miR-107 directly targets CDK8. The expression level of CDK8 mRNA and protein in miR-107 inhibitor transfected GC cell line was significantly decreased compared with control group. CONCLUSION: Our findings indicate that miR-107 is upregulated in GC and affects the proliferation of GC cells, partially through the regulation of CDK8. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_164.

Portal inflow preservation during portal diversion in small-for-size syndrome.

AIM: To investigate the impact of portal inflow on liver remnants in a stable pig model of small-for-size syndrome. METHODS: Twenty pigs underwent mesocaval shunt (MCS) surgery followed by 85%-90% hepatectomy. The control group had no shunt placement; the S1 group had portal flow maintained at an average of 2.0 times the baseline values; and the S2 group had portal flow maintained at an average of 3.2 times the baseline flow. The effect of portal functional competition on the liver remnant was investigated for 48 h postoperatively. Data were presented as mean ± SD. Statistical significance was determined using Student's t test (SPSS, Chicago, IL, United States). Values of P < 0.05 were considered statistically significant. RESULTS: At 24 h after hepatectomy, biochemical and histological changes were not significantly different between the S1 and S2 groups, but changes in both sets of variables were significantly less than in the control group. At 48 h, biochemical and histological changes were significantly less in the S2 group than in the S1 or control group. The regeneration index was significantly higher in the S2 group than in the S1 group, and was similar to that in the control group. Apoptosis index, serum lipopolysaccharide, and bacterial DNA levels were significantly lower in the S2 group than in the other two groups. CONCLUSION: Diversion of portal inflow using MCS reduces portal overflow injury. Excessive diversion of portal inflow inhibits liver regeneration following major hepatectomy. Maintaining portal inflow at an average of 3.2 times above baseline helps promote hypertrophy of the liver remnant and reduce apoptosis.

Upregulated microRNA-92b regulates the differentiation and proliferation of EpCAM-positive fetal liver cells by targeting C/EBPß.

microRNAs (miRNAs) are short noncoding RNAs that negatively regulate gene expression. Although recent evidences have been indicated that their aberrant expression may play an important role in cancer stem cells, the mechanism of their deregulation in neoplastic transformation of liver cancer stem cells (LCSCs) has not been explored. In our study, the HCC model was established in F344 rats by DEN induction. The EpCAM(+) cells were sorted out from unfractionated fetal liver cells and liver cancer cells using the FACS analysis and miRNA expression profiles of two groups were screened through microarray platform. Gain-of-function studies were performed in vitro and in vivo to determine the role of miR-92b on proliferation and differentiation of the hepatic progenitors. In addition, luciferase reporter system and gene function analysis were used to predict miR-92b target. we found that miR-92b was highly downregulated in EpCAM(+) fetal liver cells in expression profiling studies. RT-PCR analysis demonstrated reverse correlation between miR-92b expression and differentiation degree in human HCC samples. Overexpression of miR-92b in EpCAM(+) fetal liver cells significantly increased proliferation and inhibited differentiation as well as in vitro and in vivo studies. Moreover, we verified that C/EBPß is a direct target of miR-92b and contributes to its effects on proliferation and differentiation. We conclude that aberrant expression of miR-92b can result in proliferation increase and differentiation arrest of hepatic progenitors by targeting C/EBPß.

[Hepatitis B virus X protein induces malignant transformation tendency of Chang liver cells involving p16(INK4a) hypermethylation].

OBJECTIVE: To study the relationship between hepatitis B virus X (HBx) protein and DNA methylation of p16(INK4a) and the role of HBx in the carcinogenesis of hepatocellular carcinoma. METHODS: Eukaryonic expression vectors pcDNA3.1B-HBx and pcDNA3.1B were transduced into Chang liver cells by using Lipofectamine 2000 to establish the Chang-HBx liver cell line (HBx expression) and Chang-vector liver cell line (non-HBx expression). RT-PCR and Western blot were used to test the expression of p16(INK4a) in the two cell lines. The level of p16(INK4a) promoter methylation was tested by methylation specific PCR (MSP). The proliferation curves were drew by CCK-8, and S-phase in cell cycle and apoptosis were observed by flow cytometry. RESULTS: Hypermethylation of p16 can be mediated by HBx, which decreases the expression of mRNA and protein of p16. Chang-HBx cells grow faster. Chang-HBx cells have much higher S-phase population (28.96% vs. 21.53%, P<0.001; 28.96% vs. 21.5%, P<0.001) and lower apoptosis rate (2.71% vs. 3.69%, P<0.001; 2.71% vs. 3.36%, P<0.001) than Chang-vector cells and Chang cells respectively. CONCLUSION: p16(INK4a) expression was repressed by HBx protein via DNA methylation of p16(INK4a), which can induce the malignant transformation tendency of Chang cells.

[Gene expressions of DNA methyltransferase 1 and human leukocyte antigen-DRalpha in hepatocelluar carcinoma and their clinical significance].

OBJECTIVE: To investigate the clinical significance and prognostic value of the expression of DNA methyltransferase 1 (DNMT1) and human leukocyte antigen-DRalpha (HLA-DRalpha) in hepatocelluar carcinoma (HCC). METHODS: Paraffin-embedded tissues of 234 HCC underwent curative liver resection and 18 healthy adult liver samples from January 1991 to June 2002 in our department were used for the tissue microarray. Immunohistochemical technique (EnVision) was applied to detect the expression of DNMT1 and HLA-DRalpha. The relationships between DNMT1, HLA-Ralpha and clinicopathological variables were analyzed statistically. RESULTS: The rates of positive expression of DNMT1 and HLA-DRalpha were 27.4% and 39.3%. The significant correlation was present between DNMT1 and portal vein tumor thrombus, alpha fetoprotein (AFP) level or TNM staging (P < 0.05), but no significant correlation was present between DNMT1 and lymph node invasion. The significant correlation was present between HLA-DRalpha and lymph node invasion or TNM staging (P < 0.05), but no significant correlation was present between HLA-DRalpha and lymph node invasion or AFP level (P > 0.05). The postoperative median survival time was 6.87 months and the 1-, 3-, 5-year cumulative survival rate was (38.89+/-6.63)%, (19.92+/-5.48)%, (17.58+/-5.31)% respectively in HCC with positive DNMT1, while the median survival time was 40.33 months and the 1-, 3-, 5-year cumulative survival rate was (81.01+/-4.41)%, (50.78+/-5.84)%, (38.04+/-6.09)% respectively in patients with negative DNMT1(P < 0.001). The postoperative median survival time was 40.33 months and the 1-, 3-, 5-year cumulative survival rate was (81.01+/-4.41)%, (50.78+/-5.84)%, (38.04+/-6.09)% respectively in HCC with positive HLA-DRalpha, while the median survival time was 12.43 months and the 1-, 3-, 5-year cumulative survival rate was (51.72+/-6.56)%, (26.44+/-5.91)%, (13.71+/-6.83)% (P < 0.01) respectively in patients with negative HLA-DRalpha (P < 0.001). CONCLUSION: DNMT1 and HLA-DRalpha are prognostic factors for HCC, which may be promising molecular prognostic factors for HCC.