miR-9 induces cell arrest and apoptosis of oral squamous cell carcinoma via CDK 4/6 pathway.

Oral cancer remains a major public concern with considerable socioeconomic impact in the world, especially in southeast Asia. Despite substantial advancements have been made in treating oral cancer, the five-year survival rate for OSCC remained undesirable, and 35-55% patients developed recurrence within two years even with multimodality therapeutic strategies. Hence, identification of novel biomarkers for diagnosis and evaluating clinical outcome is of vital importance. MicroRNAs are 22-24 nt non-coding RNAs that could bind to 3' UTR of target mRNAs, thereby inducing degradation of mRNA or inhibiting translation. Due to its implication in regulation of post-transcriptional processes, the role of miRNAs in malignancies has been extensively studied, among which the discovery of functional miR-9 in oral squamous cell carcinoma (OSCC) remained to be elucidated. We first demonstrated that miR-9 was down-regulated in 21 OSCC patients, and we further found that forced expression of miR-9 could result in deterred cell proliferation and decreased ability to migrate and form colonies. Flow cytometry displayed cell-cycle arrested at G0/G1 phase. We next used Targetscan to predict target genes of miR-9. CDK6, a protein highly implicated in cell cycle control, was chosen for verification. Down-regulation of CDK6 and Cyclin D1 in Tca8113 transfected with miR-9 mimics indicate that the complex formed by both proteins may be the effector of the antiproliferative function of miR-9 in OSCCs. Considering small molecules are developed to target CDK4/6, our finding may provide valuable scientific evidence for research and development of therapies and diagnostic methodology in OSCCs.

Systemic bioinformatics analysis of recurrent aphthous stomatitis gene expression profiles.

Recurrent aphthous stomatitis (RAS) represents the most common chronic oral diseases with the prevalence ranges from 5% to 25% for different populations. Its pathogenesis remains poorly understood, which limits the development of effective drugs and treatment methods. In this study, we conducted systemic bioinformatics analysis of gene expression profiles from the Gene Expression Omnibus (GEO) to identify potential drug targets for RAS. We firstly downloaded the gene microarray datasets with the accession number of GSE37265 from GEO and performed robust multi-array (RMA) normalization with affy R programming package. Secondly, differential expression genes (DEGs) in RAS samples compared with control samples were identified based on limma package. Enriched gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of DEGs were obtained through the Database for Annotation, Visualization and Integrated Discovery (DAVID). Finally, protein-protein interaction (PPI) network was constructed based on the combination of HPRD and BioGrid databases. What's more, we identified modules of PPI network through MCODE plugin of Cytoscape for the purpose of screening of valuable targets. As a result, 915 genes were found to be significantly differential expression in RAS samples and biological processes related to immune and inflammatory response were significantly enriched in those genes. Network and module analysis identified FBXO6, ITGA4, VCAM1 and etc as valuable therapeutic targets for RAS. Finally, FBXO6, ITGA4, and VCAM1 were further confirmed by real time RT-PCR and western blot. This study should be helpful for the research and treatment of RAS.

The Wnt/ß-catenin signaling pathway mechanism for pancreatic cancer chemoresistance in a three-dimensional cancer microenvironment.

ß-catenin is a key protein that is encoded by the CTNNB1 gene in the Wnt signaling pathway. This study investigated the associations between ß-catenin expression and implications for the efficacy of gemcitabine on pancreatic cancer cells in a three-dimensional (3-D) cancer microenvironment. For low ß-catenin expression pancreatic carcinoma cells, the inhibition rates (IRs) for low, middle, and high doses of gemcitabine were 0.615 ± 0.079, 0.691 ± 0.093, and 0.765 ± 0.061, respectively. For the high ß-catenin expression pancreatic carcinoma cells, the IRs for the same doses were 0.325 ± 0.072, 0.453 ± 0.075, and 0.537 ± 0.056, respectively. Additionally, the evaluation of ß-catenin immunoreactivity in 31 pancreatic cancer patients revealed that the low ß-catenin protein expression group had significantly longer overall survival (OS) and disease free survival (DFS) than the high ß-catenin protein group (P < 0.05). Overall, ß-catenin protein expression levels were significantly correlated to gemcitabine sensitivity in seven pancreatic carcinoma cell lines in the 3-D cancer microenvironment. These data suggest that large-scale clinical studies are warranted to assess the role of the Wnt/ß-catenin signaling pathway on ß-catenin protein expression and chemosensitivity to gemcitabine in pancreatic cancer.

Polymorphism in Integrin ITGA2 is Associated with Ischemic Stroke and Altered Serum Cholesterol in Chinese Individuals.

BACKGROUND: Recent studies have reported contrasting results regarding the association of polymorphisms in two integrin genes, ITGA2 and ITGB3, with ischemic stroke. AIMS: The present study aimed to investigate the correlation between the ITGA2 C807T and ITGB3 T176C polymorphic loci with ischemic stroke, as well as plasma lipid and lipoprotein levels. STUDY DESIGN: Case control study. METHODS: Human venous blood samples were collected from patients admitted for ischemic stroke (n=350, 'patients') and healthy individuals (n=300, 'controls'). Blood was genotyped at these loci by polymerase chain reaction-restriction fragment length polymorphism. Plasma lipid and lipoprotein levels were measured by routine enzymatic, masking, and turbidimetry methods. RESULTS: As expected, total cholesterol, triglycerides, and low-density lipoprotein were all significantly higher in patients than in controls (p<0.05). Genotype and allele frequencies of ITGA2 C807T were significantly different between patients and controls (p<0.05), but no difference was detected in genotype or allele frequencies for ITGA3 T176C. For ITGA-2, the T allele conferred a 1.226 times higher relative risk of ischemic stroke than the C allele (odds ratio=1.226, 95% confidence interval=1.053-1.428). Similarly, total cholesterol was higher in T allele carriers than in non-carriers (p<0.05). CONCLUSION: ITGA2 C807T polymorphism is associated with ischemic stroke, with the T allele acting as a susceptibility allele that appears to confer increased cholesterol levels.

Osteopontin knockdown suppresses the growth and angiogenesis of colon cancer cells.

AIM: To investigate the effects of osteopontin (OPN) gene expression knockdown on colon cancer Lovo cells in vitro. METHODS: Four candidate small interfering RNA (siRNA) constructs targeting the OPN gene and a scrambled control sequence (NC-siRNA) were synthesized and inserted into a pGPU6/GFP/Neo expression vector. After confirmation by restriction enzyme digestion and DNA sequencing, the recombinant plasmids were subsequently transfected into a human colon cancer cell line (Lovo) using a liposome transfection method. Stably transfected cells were maintained with G418 selection and referred to as Lovo-OPN-1, -2, -3, -4, and Lovo-NC cells. Knockdown efficiency of each of the four siRNA constructs was determined by real-time reverse transcription polymerase chain reaction assays and western blotting, and the construct with the most effective silencing was used for subsequent experiments. Cell proliferation, adhesion, and Matrigel invasion assays were performed to analyze the effects of OPN knockdown in stably transfected Lovo cells. The levels of four angiogenic factors, namely vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-9 and urokinase plasminogen activator were detected by enzyme-linked immunosorbent assays (ELISA). RESULTS: Recombinant vectors containing OPN-specific and scrambled siRNA sequences were successfully constructed and stably transfected into Lovo cells. Compared with the control Lovo and Lovo-NC cells, the levels of OPN mRNA and protein expression in Lovo-OPN-1, -2, -3, and -4 were significantly reduced (all P < 0.05), with the most efficient reduction observed in Lovo-OPN-4 cells (P < 0.05). Relative to untransfected Lovo cells, OPN mRNA expression levels in Lovo-NC and Lovo-OPN-4 cells were 1.008 ± 0.067 and 0.160 ± 0.023, respectively. The relative OPN protein expression levels in Lovo, Lovo-NC, and Lovo-OPN-4 cells were 3.024 ± 0.211, 2.974 ± 0.630, and 0.121 ± 0.008, respectively. Moreover, transfection with the scrambled sequence had no effect on the expression of OPN. After 24, 48, 72, and 96 h of cultivation, absorption values at 450 nm to assess proliferation of Lovo-OPN-4 cells were 0.210 ± 0.017, 0.247 ± 0.024, 0.314 ± 0.037, and 0.359 ± 0.043, respectively, which were significantly lower than those of Lovo (0.244 ± 0.031, 0.313 ± 0.024, 0.513 ± 0.048 and 0.783 ± 0.051) and Lovo-NC cells (0.241 ± 0.029, 0.309 ± 0.022, 0.563 ± 0.023, and 0.735 ± 0.067) (all P < 0.05). The absorption values at 595 nm, which were measured in a cell adhesion assay, showed that adhesion of Lovo-OPN-4 cells (0.215 ± 0.036) was significantly decreased compared to Lovo (0.490 ± 0.037) and Lovo-NC cells (0.462 ± 0.043) (P < 0.05). The number of invasive Lovo-OPN-4 cells (16.1 ± 1.9) was also significantly decreased compared to Lovo (49.9 ± 5.4) and Lovo-NC cells (48.8 ± 4.5) (P < 0.05). ELISA assays showed significant reductions in Lovo-OPN-4 cells compared to Lovo and Lovo-NC cells with regard to the expression of VEGF (1687.85 ± 167.84 ng/L vs 2348.54 ± 143.80 ng/L and 2284.39 ± 138.62 ng/L, respectively), MMP-2 (2966.07 ± 177.36 µg/L vs 4084.74 ± 349.54 µg/L and 4011.41 ± 424.48 µg/L, respectively), MMP-9 (3782.89 ± 300.64 µg/L vs 5062.90 ± 303.02 µg/L and 4986.38 ± 300.75 µg/L, respectively) and uPA (1152.69 ± 120.79 µg/L vs 1380.90 ± 147.25 µg/L and 1449.80 ± 189.92 µg/L, respectively) (all P < 0.05). CONCLUSION: Knockdown of OPN gene expression suppresses colon cancer cell growth, adherence, invasion, and expression of angiogenic factors.

Estimation of critical gap based on Raff's definition.

Critical gap is an important parameter used to calculate the capacity and delay of minor road in gap acceptance theory of unsignalized intersections. At an unsignalized intersection with two one-way traffic flows, it is assumed that two events are independent between vehicles' arrival of major stream and vehicles' arrival of minor stream. The headways of major stream follow M3 distribution. Based on Raff's definition of critical gap, two calculation models are derived, which are named M3 definition model and revised Raff's model. Both models use total rejected coefficient. Different calculation models are compared by simulation and new models are found to be valid. The conclusion reveals that M3 definition model is simple and valid. Revised Raff's model strictly obeys the definition of Raff's critical gap and its application field is more extensive than Raff's model. It can get a more accurate result than the former Raff's model. The M3 definition model and revised Raff's model can derive accordant result.

Correlation between interleukin-18 promoter -607C/A polymorphism and susceptibility to ischemic stroke

Single nucleotide polymorphisms in the promoter region of interleukin-18 (IL-18), an inflammatory cytokine, have been linked to susceptibility to many diseases, including cancer and immune dysfunction. Here, we explored the potential association between the IL-18 -607C/A (rs1946518) promoter region polymorphism and susceptibility to ischemic stroke (IS). This locus was amplified from peripheral blood samples of 386 IS patients (cases) and 364 healthy individuals (controls) by the polymerase chain reaction with sequence-specific primers. Significant differences were observed by the χ2 test in the -607C/A (rs1946518) genotype and allele frequencies between cases and controls (P < 0.05). Furthermore, after excluding for age, gender, smoking status, and hypertension, logistic regression indicated that IS susceptibility of -607C carriers increased 1.6 times (OR = 1.601, 95%CI = 1.148-2.233, P = 0.006) compared to -607A carriers. Additionally, similar increases in IS risk were noted for male patients or patients less than 65 years old. In conclusion, IL-18 -607C/A (rs1946518) promoter polymorphism is associated with IS susceptibility, and the C allele may confer increased IS risk.

Correlation between interleukin-18 promoter -607C/A polymorphism and susceptibility to ischemic stroke.

Single nucleotide polymorphisms in the promoter region of interleukin-18 (IL-18), an inflammatory cytokine, have been linked to susceptibility to many diseases, including cancer and immune dysfunction. Here, we explored the potential association between the IL-18 -607C/A (rs1946518) promoter region polymorphism and susceptibility to ischemic stroke (IS). This locus was amplified from peripheral blood samples of 386 IS patients (cases) and 364 healthy individuals (controls) by the polymerase chain reaction with sequence-specific primers. Significant differences were observed by the χ2 test in the -607C/A (rs1946518) genotype and allele frequencies between cases and controls (P < 0.05). Furthermore, after excluding for age, gender, smoking status, and hypertension, logistic regression indicated that IS susceptibility of -607C carriers increased 1.6 times (OR = 1.601, 95%CI = 1.148-2.233, P = 0.006) compared to -607A carriers. Additionally, similar increases in IS risk were noted for male patients or patients less than 65 years old. In conclusion, IL-18 -607C/A (rs1946518) promoter polymorphism is associated with IS susceptibility, and the C allele may confer increased IS risk.

[Plasma homocysteine levels in ischemic stroke patients with obstructive sleep apnea].

OBJECTIVE: To investigate the association of plasma homocysteine and OSA (obstructive sleep apnea) syndrome in ischemic stroke (IS). METHODS: A total of 92 male IS patients were classified by apnea hypopnea index (AHI) into 2 groups: non-OSA group (AHI < 5/h) and OSA group (AHI > or = 5). All patients were tested for plasma homocysteine when polysomnography was finished at (14 +/- 2) d after the onset of IS. RESULTS: The mean level of homocysteine was significantly higher in the OSA group than that in the non-OSA group (17 +/- 5 vs 11 +/- 3 micromol/L, P < 0.01). Pearson correlation analysis revealed a positive correlation between the homocysteine level and the severity of AHI (r = 0.482, P < 0.01). Further multiple linear regression analysis showed that AHI and folate were independent predictors of homocysteine level (R2 = 0.553, P < 0.01, beta for AHI = 0.671, beta for folate = -0.256). CONCLUSION: The severity of OSA is significantly associated with an elevated level of homocysteine in IS patients. And this association is independent of other causative factors of an elevated level of homocysteine.

[Detection of tumor cells in peripheral blood of patients with gastric cancer using mRNA of MAGE genes as markers].

OBJECTIVE: To develop a sensitive and specific RT-PCR assay using the mRNA of MAGE-1 and MAGE-3 genes as specific tumor markers for the detection of the tumor cells in the peripheral blood of patients with gastric cancer. METHODS: Peripheral blood was obtained from 40 patients with gastric cancer and from 20 healthy volunteers. The mRNA of MAGE-1 and MAGE-3 genes in the peripheral blood mononuclear cells (PBMC) was detected by RT-PCR. The expressions of MAGE-1 and MAGE-3 mRNA in the tumor tissues of these gastric cancer patients were also detected by RT-PCR. Meanwhile,CEA expression by nested RT-PCR in PBMC of 40 gastric cancer patients was also detected. RESULTS: Of 40 gastric cancer patients, MAGE-1 and MAGE-3 mRNA were positive in 47.5% (19/40) and 25% (10/40) of PBMC respectively, and in 62.5% (25/40) and 30% (12/40) of gastric cancer tissues respectively. As a whole, in the PBMC of 40 gastric cancer patients, 25 (62.5%) samples were found to express at least one type of MAGE mRNA. In the patients whose tumors did not express MAGE-1 and/or MAGE-3 genes, the corresponding MAGE mRNA was also undetected in their PBMC. There was no expression of MAGE-1 or MAGE-3 gene in the PBMC from the 20 healthy donors. The positive rate of MAGE mRNA in PBMC was closely correlated with the tumor stage and lymph node metastasis (P <0.05). Positive rate of CEA gene expression was 32.5% (13/40) in the PBMC of 40 gastric cancer patients, 29 (72.5%)samples were detected to express at least one type of MAGE gene and CEA gene mRNA. CONCLUSIONS: MAGE-1, MAGE-3 and CEA mRNA are specifically detected with high percentage in the PBMC of gastric cancer patients by RT-PCR. They could be used as specific tumor markers for the detection of the circulating gastric cancer cells, and the detection results may be helpful to evaluate the prognosis of gastric cancer patients.

Effects of 5-hydroxytamine and its antagonists on hepatic stellate cells.

BACKGROUND: Hepatic stellate cell (HSC) plays a key role in hepatic fibrosis. This study was undertaken to investigate the expression of 5-hydroxytamine receptors in HSC and the effect of 5-hydroxytamine on biological characteristics of HSC. METHODS: Liver ex vivo perfusion of collagenase and density gradient centrifugation were used to isolate HSCs. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect the expression of 5-hydroxytamine receptor subtypes 1A, 2A, 2B and 3. Western blot hybridization was used to elucidate the effect of 5-hydroxytamine and its 2A receptor antagonist ketanserin and 3 receptor antagonist ondanosetron on the expression of transforming growth factor-beta1 (TGF-beta1) and Smad4 in HSC. RESULTS: HSC expressed 5-hydroxytamine receptor subtypes 1A, 2A and 2B. 5-hydroxytamine significantly increased the expression of TGF-beta1 and Smad4 in HSC (P<0.05). This action can be antagonized by ketanserin, not by ondanosetron. CONCLUSIONS: HSC expresses 5-hydroxytamine receptors. 5-Hydroxytamine could effect the biological characteristics of HSC through its receptor mediation, and may play a role in the pathogenesis of liver cirrhosis and portal hypertension.

Expression of cancer-testis antigens in hepatocellular carcinoma.

AIM: To investigate the expression of cancer-testis (CT) antigens MAGE-1, SSX-1,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunotherapy for HCC. METHODS: Expression levels of MAGE-1, SSX-1, CTp11 and HCA587 mRNA were detected with reverse transcription polymerase chain reaction (RT-PCR) in HCC tissues and corresponding adjacent non-cancerous tissues from 105 HCC patients, 40 samples of cirrhosis and normal liver tissues. Genes of five samples with positive PCR results were sequenced. RESULTS: Of 105 HCC tissues, MAGE1, SSX-1,CTp11 and HCA587 mRNA expressions were detectable in 75.2%(79/105), 72.4%(76/105), 62.9%(66/105) and 56.2%(59/105) of HCC samples, respectively. About 93.3%(98/105), 72.4%(76/105), 48.6%(51/105) and 37.1%(39/105) of HCC tissues positively expressed at least one, two, three, and four members of CT antigens, respectively. Conversely, only SSX-1 could be detectable in 2.9%(3/105) of the corresponding adjacent non-HCC tissues in which no metastatic lesion was found. Of the latter 3 patients, biopsy samples far from tumor were obtained in 2 patients and RT-PCR indicated no expression of SSX-1 mRNA in these two samples. In addition, none of 40 samples of cirrhotic and normal liver tissues expressed CT antigen gene mRNA. DNA sequences confirmed that the RT-PCR products were true target cDNA. No relationship was found between expression of CT antigens and clinico pathological indicators such as age, gender, tumor size, degree of tumor differentiation, serum alpha-fetoprotein level and infection of hepatitis B virus or hepatitis C virus (P>0.05). CONCLUSION: CT antigens genes (MAGE-1, SSX-1, CTp11 and HCA587) are expressed with high percentage and specificity in HCC and their products are promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of multiple members of CT antigens in HCC provides possibility of polyvalent vaccinations for HCC.

[Expression of MAGE-B genes in hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of MAGE-B genes in hepatocellular carcinoma (HCC) in order to find new targets for immunotherapy. METHODS: The expression of MAGE-B1, B2, A1 and A3 mRNA was detected using RT-PCR in HCC tissues and the corresponding adjacent non-HCC tissues from 47 HCC patients, 30 samples of cirrhosis and normal liver tissues. Four samples selected randomly from MAGE-B1 or B2 with positive RT-PCR results were sequenced to confirm the results of RT-PCR. The relationship between the expression of MAGE-B and some clinicopathological parameters was analyzed. RESULTS: MAGE-B1 mRNA and MAGE-B2 mRNA were detected in 44.7% (21/47) and 61.7% (29/47) of HCC samples, respectively, while neither MAGE-B1 nor MAGE-B2 could be detected in the corresponding adjacent non-HCC liver tissues. In addition, none of 30 samples of cirrhosis and normal liver tissues was shown to express both MAGE-B genes. The DNA sequence confirmed that the RT-PCR products were truly target cDNA. The frequency of the expression of MAGE-A1 and A3 was 74.5% (35/47) and 44.7% (21/47), respectively. There was significant correlation between the expression of MAGE-B and MAGE-A (P < 0.05). However, the positive expression of MAGE-B was observed in 5 out of 12 HCC tissues without expression of MAGE-A1 and/or A3. When all four MAGE genes were examined, the positive rate of expression of one, two, three and four genes was 83.0% (39/47), 55.3% (26/47), 48.9% (23/47), and 38.3% (18/47) of 47 HCC tissues, respectively. No correlation was found between the expression of MAGE-B and clinical parameters such as age, sex, tumor size, degree of tumor differentiation, serum alpha-fetoprotein level and hepatitis B virus or hepatitis C virus infection (P > 0.05). CONCLUSION: MAGE-B genes are expressed with relatively high frequency and specificity in HCC. Most HCC patients with positive expression of at least one member of MAGE-B or MAGE-A gene family are adequate candidates to receive specific immunotherapy. Frequent co-expression of multiple members of MAGE-B and MAGE-A subfamilies provides the possibility of using polyvalent vaccines to achieve more effective immunotherapeutic results.

[Expression and clinical significance of hepatocellular cancer antigen genes in human hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of four hepatocellular cancer antigen (HCA) gene mRNA in hepatocellular carcinoma. METHODS: The expression of HCA90, HCA519, HCA520, HCA587 mRNA was detected using RT-PCR in HCC tissues and the corresponding adjacent non-HCC tissues from 46 HCC patients, cirrhosis tissues from 10 samples and normal liver tissues from 10 samples. The relationship between positive expression rate of HCA gene and clinical and lab data was evaluated. RESULTS: Of 46 HCC tissues, HCA90, HCA519, HCA520 and HCA587 mRNA were detectable in 65.2%, 76.1%, 45.7% and 32.6%, respectively. At least one HCA gene mRNA was positive in 82.6% of HCC tissues. Only weak expression of HCA519 could be detectable in 6.5% of the corresponding adjacent non-HCC tissues. None of 10 samples of cirrhosis and normal liver tissues expressed any HCA gene mRNA. No correlation was found between the expression of HCA and clinical date such as age, sex, tumor size, tumor differentiation, serum alpha-fetoprotein level and hepatitis B virus infection or hepatitis C virus infection (P > 0.05). However, in some patients with normal serum alpha-fetoprotein (< 25 ng/L), specific expression of HCA genes was observed. CONCLUSION: HCA gene mRNA is expressed with a high percentage and specificity in hepatocellular carcinomas and their products are new potential promising targets for immunotherapy of HCC.

[Expression of 5-hydroxytamine receptors in hepatic stellate cell and action of 5-hydroxytamine on biological characteristics of hepatic stellate cell].

OBJECTIVE: To investigate the expression of 5-hydroxytamine receptors in hepatic stellate cells HSCs and action of 5-hydroxytamine on biological characteristics of HSC. METHODS: Liver ex vivo perfusion of collagenase and density gradient centrifugation were used to isolate hepatic stellate cell. RT-PCR was used to detect the expression of 5-hydroxytamine receptor subtypes 1A, 2A, 2B and 3. Western blot hybridization was used to elucidate the effect of 5-hydroxytamine and its 2A receptor antagonist ketanserin and 3 receptor antagonist ondanosetron on expression of transforming growth factor-beta1 (TGF-beta1) and Smad4 in HSC. HSCs were cultured on silicone membrane. The effect of 5-hydroxytamine, ketanserin and ondanosetron on cell contraction were studied. RESULTS: HSC expressed 5-hydroxytamine receptors subtypes 1A, 2A and 2B. 5-hydroxytamine significantly increased the expression of TGF-beta1 and Smad4 in HSC (P < 0.05). This was antagonized by ketanserin, not by ondanosetron. 5-hydroxytamine induced cell contraction in a dose-dependant manner. Ketanserin antagonized this action, but ondanosetron did not. CONCLUSIONS: HSCs express 5-hydroxytamine receptors. 5-hydroxytamine could affect the biological characteristics of HSC through its receptor mediation, and may play a role in the pathogenesis of liver cirrhosis and portal hypertension.