Volume 120  ·   Issue 23  ·  2007

Irritable bowel syndrome(IBS) is highly prevalent and can affect up to 20% of the population.1 It is a common gastrointestinal(GI) disorder associated with alterations in motility,secretion and visceral sensation。

Abstract：Background Hyperhomocysteinemia (HHcy)-mediated dysfunction of endothelial NO system is an important mechanism for atherosclerotic pathogenesis.Dimethylarginine dimethylaminohydrolase (DDAH) is the key enzyme for degrading asymmetric dimethylarginine (ADMA),which is an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS).This study was designed to investigate whether the dysfunction of endothelial NO system originates from HHcy-mediated aberrant methylation modification in promotor region of DDAH2 gene.Methods Human umbilical vein endothelial cells (HUVECs) were cultured to the third generation and treated with homocysteine (Hcy) at different concentrations (0,10,30,100,and 300 μmol/L) for 72 hours.The methylation pattern in promoter region CpG island of DDAH2 gene was analyzed by nested methylation-specific PCR (nMSP).The mRNA expression of eNOS gene and DDAH2 gene was detected by semi-quantitative RT-PCR.The activity of DDAH2 and eNOS in cells,and the concentrations of ADMA and NO in culture medium were assayed respectively.Results Mild increased concentration of Hcy (10 and 30 μmol/L) induced hypomethylation,while high concentration of Hcy (100 and 300 μmol/L) induced hypermethylation in the promoter CpG island of DDAH2 gene.The mRNA expression of DDAH2 increased in mild enhanced concentration of Hcy,and decreased in high concentration of Hcy correspondingly.The inhibition of DDAH2 activity,the increase of ADMA concentration,the reduction of eNOS activity and the decrease of NO production were all consistently relevant to the alteration of Hcy concentration Conclusion The increased concentration of Hcy induced aberrant methylation pattern in promotor region of DDAH2 gene and the successive alterations in DDAH/ADMA/NOS/NO pathway,which showed highly relevant and dose-effect relationship.The results suggested that the dysfunction of endothelial NO system induced by HHcy could be partially originated from Hcy-mediated aberrant methylation in DDAH2 gene。

Abstract：Background Hypertensive crisis could be found after operation in patients with hypertensive intracerebral hemorrhage (HICH).The aim of this study was to explore the changes and the roles of some vasoactive polypeptides during postoperative hypertensive crisis in patients with HICH.Methods A total of 31 patients,who were admitted for craniotomy,were enrolled into this study.After the operation,the patients were divided into three groups.Group Ⅰ consisted of 9 patients with postoperative hypertensive crisis,and group Ⅱ was composed of 13 patients without postoperative hypertensive crisis.Nine patients,who denied history of hypertension or HICH,were set as group Ⅲ.The levels of some vasoactivators in the three groups were measured before and after the operation.The differences in the results among the groups were analyzed using the ANOVA.The data collected before and after the operation in the group Ⅰ was compared by Wilcoxon test.Results The concentration of endothelin in group Ⅰ was significantly higher than that in group Ⅲ (P<0.05).The level of thromboxane A2 and the ratio of thromboxane B2 to 6-keto-PGF1 a in group Ⅰ were significantly higher than those in the other two groups (P<0.05).In group Ⅰ,the levels of plasma renin activity,angiotensin Ⅱ,aldosterone,catecholamine,and endothelin before the operation were significantly higher than those determined after the operation (P>0.05).Conclusions Postoperative hypertensive crisis may be due to the increased thromboxane A2 and relatively inadequate prostacyclin,especially 6-keto-PGF1α.The increased level of endothelin and intraoperative stimulation also play a certain role in the development of postoperative hypertensive crisis。

Abstract：Background Osteopontin(OPN)is one kind of cytokine which can play a number of roles in promoting activation of T lymphocyte,regulating balance between Th1 and Th2,participating in cell-induced immunologic response and stimulating B lymphocyte to express multi-clone antibodies.Some researches have showed that OPN may be involved in the pathogenesis of systemic lupus erythematosus (SLE).The aim of this study was to investigate possible association of a single nucleotide polymorphism (SNP) at position 9250 in exon 7 of the OPN gene (OPN gene 9250) with SLE in Chinese patients.Methods Totally 158 patients (18 males and 140 females) fulfilled the revised criteria for SLE by the American College of Rheumatology in 1982 and 180 healthy volunteer controls (34 males and 146 females),all from the south of China,consented to participate in the study.OPN gene 9250 polymorphism was detected by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).Results The frequency of TT genotype of the OPN gene 9250 was significantly lower (52.5% vs 70%,P<0.05)and the frequency of TC genotype of the OPN gene 9250 was significantly higher(43.7% vs 29.4%,P<0.05)in SLE patients than in controls.There were significant differences in OPN gene 9250 allele and phenotype frequencies between the SLE patients and controls (P<0.05).When the SLE patients and controls were separated into men and women,significant differences of frequencies were noted in TT genotype,TC genotype and allele of the OPN gene 9250 in women (P<0.05) but not in men (P>0.05).Conclusions OPN gene 9250 polymorphism appears to be associated with susceptibility to SLE in Chinese Han ethnic population。

Abstract：Background Checkpoint kinase 2 (CHK2) is a DNA damage-activated protein kinase which is involved in cell cycle checkpoint control.CHK2 gene could be a candidate gene for colorectal cancer susceptibility.But there are few systematic repots on mutation of CHK2 in colorectal cancer.Methods The mutations of all 14 exons of CHK2 in 56 colorecfal cancer cell lines were screened systematically.using denaturing high-performance liquid chromatography (DHPLC) to screen the mismatches of the CHK2 exons amplified products,and then the suspected mutant cell lines were scanned by nucleotide sequence analysis.Results VACO400 in CHK2 exon 1a was suspected to have mutation by DHPLC and confirmed by sequence,but this was nonsense mutation.C106,CX-1,HT-29,SK01,SW480,SW620 and VACO400 in CHK2 exon 1b were confirmed to have the same nonsense mutation in 11609 A>G.DLD-1 and HCT-15 in CHK2 exon 2 were confirmed to have missense mutation R145W.which was heterozygous C>T missense mutation at nucleotide 433.leading to an Arg>Trp substitution within the FHA domain.Conclusions The CHK2 mutation in colorectal cancer is a low frequency event.There are just 10 cell lines to have sequence variations in all the 14 exons in 56 colorectal cancer cell lines and only DLD-1/HCT-15 had heterozygous missense mutation.These findings may give useful information of susceptibility of colorectal cancer as single nucleotide polymorphysim。

Abstract：Background Histone deacetylase inhibitors (HDACIs) have been reported to induce apoptosis in cancer cells.The effects of trichostatin A (TSA) on gastric cancer cells have not been well characterized.This study was aimed to explore the effects and mechanisms of TSA on human gastric cancer SGC-7901 cells.Methods The cells were treated with TSA and analyzed by cell proliferation assay,Western blot,TUNEL assay,flow cytometry by fluorescein isothiocyanate (FITC) conjugated with Annexin V and PI staining,immunofluorescence analysis,analysis of subcellular fractionation,gene chips and real time polymerase chain reaction (PCR).Results TSA could inhibit cell growth and induced apoptosis in gastric cancer SGC-7901 cells through the regulation of apoptosis-related genes,such as Bcl-2,Bax and survivin.Further study indicated that the pan-caspase inhibitor z-VAD-fmk did not inhibit the apoptosis induced by TSA,and we did not observe the cleavage of poly ADP ribose polymerase(PARP)after TSA treatment too.In addition,apoptosis inducing factor (AIF) and EndoG were found to translocate from mitochondria to nucleus in the immunofluorescence assay and the Western analysis of subcellular fractionation confirmed the result of immunofluorescence assay.Conclusions The apoptosis induced by TSA in gastric cancer SGC-7901 cells involves a caspase-independent pathway。

Abstract：Background Bcl-2,the anti-apoptotic protein is overexpressed in the majority of gastric cancers and associated with its pathogenesis.To better understanding of the role of Bcl-2,RNA interference(RNAi)was used to inhibit Bcl-2 expression in the human gastric cancer cells in vitro and in vivo.Methods Bcl-2 small interfering RNA (siRNA) was transfected into human gastric cancer cells SGC-7901,and Bcl-2 expression was monitored by real-time polymerase chain reaction (PCR) and Western blot.Cell proliferation,apoptosis,and telomerase activity were examined by MTT,flow cytometry.and TRAP assay,respectively.Gastric cancer cells treated with 100 nmol/L Bcl-2 siRNA were subcutaneously transplanted into nude mice and tumor growth was assessed.Results Bcl-2 siRNA significantly inhibited the expression of Bcl-2 in human gastric cancer cells at both mRNA and protein levels in a time-and dose-dependent manner.Bcl-2 siRNA also decreased telomerase activity (by 78.76%)and increased the rate of apoptosis(by 37.47%).SGC-7901 cell growth was also significantly suppressed in vivo and in vitro.Conclusions Bcl-2 expression knockdown suppressed the growth of gastric cancer cells.Thus,Bcl-2 may play a very important role in carcinogenesis of gastric cancer and its knockdown may offer a new potential gene therapy approach for human gastric cancer in future。

Abstract：Background The role of epigenetics in gene expression regulation and development significantly enhances our understanding of carcinogenesis.All the tumor related genes may be the target of epigenetical or genetic regulation.We selected some epigenetically regulated genes for cDNA array analysis and observed variability in the expression of the DICER1 gene in distinct stages of gastric cancer.The aim of this study was to assess the correlation between the expression of DICER1,an epigenetically regulated gene,and gastric cancer.Methods To detect the expression of 506 tumor-associated genes,including DICER1,in the matched cancerous mucosa,pre-malignant lesion (adjacent mucosa),non-cancerous gastric mucosa and distant lymphocyte metastatic lesion in 3 cases of gastric cancers using cDNA array.DICER1 mRNA expression and DICER1 protein expression were further analyzed by Real-time PCR and Western blot in 32 cases of progressive gastric cancer.DICER1 protein expression was also detected in 33 early and 30 progressive gastric cancers by the immunohistochemistry (IHC) method.Results In 3 cases of gastric cancer cDNA array showed dramatically decreased expression of DICER1 in pre-malignant Iesion,cancerous mucosa and distant lymphocyte metastatic lesions compared with matched noncancerous gastric mucosa,pre-malignant lesion and cancerous mucosa.Real-time PCR results showed that the expression level of DICER1 mRNA in gastric cancer was significantly down-regulated compared to normal gastric tissue (P<0.05).The IHC assay also showed that the expression of DICER1 was significantly decreased in progressive gastric cancer.Among the 63 cases of gastric cancers,13/33 early(39.4%)and 19/30(63.3%)progressive cancers showed negative expression of DICER1(50.8%).The difference in expression of DICER1 between early and progressive gastric cancers was significant(P<0.01).The result of Western blotting showed that DICER1 protein was down-regulated significantly in advanced gastric cancer(P<0.05).Conclusions DICER1 expression is decreased during the progression of gastric cancer,especially in progressive gastric cancers,which indicating DICER1 may play an important role in the development of cancer and the epigenetical regulation involved。

Abstract：Background Esophageal cancer is one of the most common malignancies in the world.In order to identify the proteins associated with esophageal squamous cell carcinomas(ESCC),we analyzed the protein profiles of ESCC cases with tumor and matched adjacent normal tissues.Methods Two-dimensional electrophoresis(2-DE)was carried out to analyze the protein profiles.Dysregulated protein spots were identified by Matrix-Assisted Laser Desorption Ionization Time-of-Flight(MALDI-TOF)and verified by liquid chromatography/electrospray ionization ion trap-mass spectrometry/mass spectrometry(LC-ESI-IT MS).RT-PCR and immunohistochemistry on tissue microarray were performed to confirm the gene dysregulation in esophageal cancerous tissues.RNA interference (RNAi)was used to knock down the gene expression in ESCC cell lines.Apoptosis assay with annexin V-FITC/PI staining was conducted and cells were analyzed by flow cytometry.Results 2-DE showed that two protein spots with approximate molecular weights and different pl were elevated in 12 out of 18 ESCCs as compared to the corresponding normal tissues.Both the two spots were identified as MnSOD by MALDI-TOF and were verified by LC-ESI-IT MS.MnSOD overexpression was detected in 14 tumors out of 24 cases by RT-PCR and 52 tumors out of 116 cases by immunohistochemistry comparing to normal epithelia.siRNA-mediated silencing of MnSOD in KYSE450 and KYSE150 cell lines revealed that MnSOD protected ESCC cells from apoptosis induced by ultraviolet(UV)and doxorubicin(DOX).Conclusions These findings suggest that there existed two isoforms of MnSOD protein in normal and tumor esophageal tissues.MnSOD was overexpressed in ESCC and its up-regulation in esophageal cancer cells was associated with apoptosis resistance。

Abstract：Background Cigarette smoking has been verified as the risk factor of esophageal squamous cell carcinoma(ESCC).Overexpression of cyclooxygenase 2(COX-2)is shown in ESCC.The objective of this study was to investigate the effects of cigarette smoking ethanol extract(EE)on the proliferation of the human ESCC cell Iines,and to explore the correlation between the proliferation rate of human ESCC cell lines and the expression pattern of COX-2.Whether aspirin can inhibit the proliferation of the ESCC cell lines pretreated with EE.and regulate the mRNA expression levels of COX-2 are also examined.Methods Two human ESCC cell Iines were selected.EC109 was poorly differentiated and EC9706 was highly differentiated.EC109 and EC9706 were treated with EE and aspirin for different time course.The cell growth of ESCC was measured by MTT reduction assay and the expression of COX-2 was measured by RT-PCR and Western blot analysis.Results EE promoted the proliferation of EC109 and EC9706 in dose- and time-dependent manners.In the concentration range (10-100 μg/ml for EE)and in the time range(24-72 hours)after addition of EE,the cell proliferation was prominent in an up-scaled manner respectively.Aspirin could inhibit the proliferation of cell lines EC109 and EC9706.pretreated with EE for 5 hours,in a dose-dependent manner.In the concentration range (0.5-8.0 mmol/L for aspirin),the cell growth inhibition was prominent in an up-scaled manner accordingly (P<0.05).The effect of EE on cell proliferation was correlated with the up-regulation of COX-2 gene.However,the cell growth inhibition of aspirin was correlated with the down-regulation of COX-2 gene.Conclusions EE can stimulate the proliferation of human ESCC cell lines EC109 and EC9706,most likely through up-regulating the expression of COX-2.Aspirin can inhibit the proliferation of ESCC cell lines induced by EE,which suggests it may be advantageous in the chemoprevention and therapy of human tobacco-related ESCC.And its effect is likely to be related with modulating COX-2 activity。

Abstract：Background Gastric varices (GV) are life-threatening for patients with portal hypertension.Endoscopic injection with butyl cyanoacrylate (BC),the mainstay of the therapy for GV,has been reported to be effective for hemostasis of bleeding varices.but its efficacy in the obliteration of GV and impact on the survival of patients still needs clarification.Here we summarized our experience of 10 years'practice to evaluate the efficacy and safety of endoscopic therapy using BC for GV patients.Methods From January 1997 to April 2006.GV cases treated with endoscopic injection using BC were collected.The "sandwich method" and the "modified sandwich method" were used to inject BC intravascularly.Retrograde analysis was made on the data of treatment and follow-up.Results A total of 635 GV cases treated with endoscopic injection using BC were collected,most of them (90.2%) suffered from post-hepatitis cirrhosis.Emergency hemostasis was achieved in 139 out of 146 sessions (95.2%).Complications occurred in 32 cases (5.2%),including hemorrhage due to early expulsion of tissue glue (3.1%),septicemia (1%) and ectopic thrombosis (0.5%),such as spleen infarction.Endoscopic follow-up in 503 patients showed complete disappearance (76.9%),collapse (17.3%) or remnants (5.8%) of gastric varices.A total of 550 patients were followed up clinically for 3 to 115 months.Of these patients,44 had recurrent bleeding (8.0%) and 44 died from hepatic failure,recurrent bleeding,hepatic carcinoma or other causes.The longest survival was 115 months,with a median survival of 25 months.Survival rates at 1,2,3,4 and 5 year were 95%,92%,90%,83% and 81%,respectively.Conclusions Endoscopic sclerotherapy with BC is effective for the hemostasis of bleeding GV.as well as obliteration of GV which contributes to less rebleeding and better survival.The modified sandwich method may be useful to minimize ectopic embolism.which we speculated to result from excess iodized oil。

Abstract：Objective To review the research progress on Type IV secretion system (T4SS) in Helicobacter pylori.Data sources The data used in this review were identified by searching of PUBMED (1995-2007) online resources Study selection Mainly original articles and critical reviews written by major pioneer investigators of this field were selected.Results The research progress on T4SS in Helicobacter pylori was summarized.The structure and function was discussed.Conclusions T4SS is not only involved in toxin secretion and injection of virulence factors into eukaryotic host target cells,but also involved in horizontal DNA transfer to other bacteria and eukaryotic cells,through DNA uptake from or release into the extracellular milieu.It provides a new insight into the pathogenicity of Helicobacter pylori and a novel target for antimicrobials development.However,many challenges remain for us in understanding the biological role of T4SS in Helicobacter pylori。

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by recurrent abdominal pain or discomfort associated with altered bowel movements.It affects 8%-22% of the population in Western countries and the prevalence of IBS prevalence is 5%-10% in most Asian communities。

Reflux symptom questionnaire (RSQ) is a useful tool in epidemiological study of gastroesophageal reflux disease (GERD),(1,2) but the correlation between RSQ and the refluX oesophagitis (RE) is still unclear。

Neurofibromatosis type I (NF-I) is an autosomal dominant inherited disease caused by a mutated NF-I gene on chromosome 17,which produces inactive neurofibromin。

Aortoesophageal fistula (AOF) is a rare (0.01%-0.08%),but life threatening cause of upper gastrointestinal haemorrhage。