Helicobacter pylori vacA genotypes and cagA status and their relationship to associated diseases

Helicobacter pylori (H. pylori ) is a major causativebacterium of chronic gastritis, peptic ulcer and mucosaassociated lymphoid tissue lymphoma in humans, and associated with an increased risk of gastric cancer[1 -8]. An important virulant factor of H. pylori is the vacuolating cytotoxin ( VacA ) encoded by vacA that induces cytoplasmic vacuolation in target cells both in vitro and in vivo[9-11]. VacA is produced as a 140 kDa precursor which contains an N-terminal signal peptide and an approximately 33 kDa C-terminal outer membrance exporter. The precursor is cleaved at both N-terminal and C-terminal and secreted into the extracellular milieu as a 95 kDa mature protein. The mature protein futher undergoes specific cleavage to yield 37 kDa and 58 kDa subunits[12-14] Although vacA is present in all H. pylori strains, only about 50% to 60% of strains can induce vacuolation of epithelial cells as assessed by the HeLa cell assay. vacA shows considerable genetic variation in H. pylori isolated from all over the world and contains at least two variable regions. The s region exists as sl or s2 allelic types. Among type sl strains, subtypes sla and slb have been identified. The m region occurs as ml or m2 allelic types. Specific vacA genotype of H. pylori strains are associated with the production of the cytotoxin in vitro, epithelial damage in vivo, and clinical consequences[15-27]. The other virulant factor is the cytotoxin-associated protein (CagA) encoded by the cytotoxin-associated gene (cagA). The cagA gene is present in about 60% to 70% of strains and all of these strains express the cagA. The presence of cagA is also associated with the production of the cytotoxin in vitro, and clinical outcome[24-30]. The aim of this study was (i) to identify vacA genotypes and cagA status of H. pylori isolated from Chinese patients; (ii) to evaluation the relatioship beween vacA genotypes, cagA status and related gastroenterological disorders.

Matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-1 expression in fibrotic rat liver

INTRODUCTIONLiver fibrosis is an excessive deposition ofextracellular matrix(ECM)resulted from bothincreased synthesis and decreased degradation.Matrix metalloproteinases(MMPs)represent agroup of neutral proteinases with variable

Induction of apoptosis by arsenic trioxide and hydroxycamptothecin in gastric cancer cells in vitro

AIM To study the effects of arsenic trioxide andHCPT on different degrees of differentiated gastriccancer cells（SGC-7901,MKN-45,MKN-28）withrespect to both cytotoxicity and induction ofapoptosis in vitro.METHODS The cytotoxicity of As2O3 and HCPTon gastric cancer cells was determined by MTTassay.Morphologic changes of apoptosis ofgastric cancer cells were observed by lightmicroscopy and transmission electron microscopy.Apoptosis and cell cycle changes of gastric cancercells induced by HCPT and As2O3 were investigatedby TUNEL method and flow cytometry.RESULTS As2O3 and HCPT had remarkablecytotoxic effects on different degrees ofdifferentiated gastric cancer cells.The IC50ofAs2O3 on well differentiated gastric cancer cellMKN-28,moderately differentiated gastric cancercell SGC-7901,and poorly differentiated gastriccancer cell MKN-28 were 8.91 μmol/L,10.57μmol/L,and 11.65 μmol/L,respectively.The IC50of HCPT on MKN-28,SGC-7901,and MKN-45 were9.35 mg/L,10.21 mg/L,and 12.63 mg/Lrespectively after 48 h treatment.After 12 h ofexposure to both drugs,gastric cancer cellsexhibited morphologic features of apoptosis,including cell shrinkage,nuclear condensation, and formation of apoptotic bodies.A typicalsubdiploid peak before G0/G1 phase was observedby flow cytometry.The apoptotic rates of SGC-7901,MKN-45,and MKN-28 were 13.84%,22.52%,and 9.68%,respectively after 48 hexposure to 10 μmol/L As2O3.The apoptotic ratesof SGC-7901,MKN-45,and MKN-28 were 21.88%,12.35%,and 30.26%,respectively after 48 hexposure to 10 mg/L HCPT.The apoptotic indicewere 7%-15% as assessed by TUNEL method.The effect of As2O3 on SGC-7901 showedremarkable cell cycle specificity,which inducedcell death in G1 phase,and blocked G2/M phase.HCPT also showed a remarkable cell cyclespecificity,by inducing cell death and apoptosis inG1 phase and arrest of proliferation at S phase.CONCLUSION As2O3 and HCPT exhibitsignificant cytotoxicity on gastric cancer cells byinduction of apoptosis.As2O3 and HCPT mighthave a promising prospect in the treatment ofgastric cancer,which needs to be further studied.

Suppression of P-gp induced multiple drug resistance in a drug resistant gastric cancer cell line by overexpression of Fas

AIM To observe the drug sensitizing effect andrelated mechanisms of fas gene transduction onhuman drug-resistant gastric cancer cellSGC7901/VCR(resistant to Vincristine).METHODS The cell cycle alteration wasobserved by FACS.The sensitivity of gastriccancer cells to apoptosis was determined by invitro apoptosis assay.The drug sensitization ofcells to several anti-tumor drugs was observedby MTT assay.Immunochemical method wasused to show expression of P-gp and Topo Ⅱ ingastric cancer cells.RESULTS Comparing to SGC7901 and pBK-SGC7901/VCR,fas-SGC7901/VCR showeddecreasing G2 cells and increasing S cells,theG2 phase fraction of pBK-SGC7901/VCR wasabout 3.0 times that of fas-SGC7901/VCR,but Sphase fraction of fas-SGC7901/VCR was about1.9 times that of pBK-SGC7901/VCR,indicatingS phase arrest of fas-SGC7901/VCR.FACS alsosuggested apoptosis of fas-SGC7901/VCR,fas-SGC7901/VCR was more sensitive to apoptosisinducing agent VM-26 than pBK-SGC7901/VCR.MTT assay showed increased sensitization offas-SGC7901/VCR to DDP,MMC and 5-FU,butsame sensitization to VCR according to pBK-SGC7901/VCR.SGC7901,pBK-SGC7901/ VCRand fas-SGC7901/VCR had positively stainedTopo Ⅱ equally.P-gp staining in pBK- SGC7901/VCR was stronger than in SG07901,but there was little staining of P-gp in fas.SGC7901/VCR.CONCLUSION fas gene transduction couldreverse the MDR of human drug-resistant gastriccancer cell SGC7901/VCR to a degree,possiblybecause of higher sensitization to apoptosis anddecreased expression of P-gp.

Colorectal cancer in Guangdong Province of China:A demographic and anatomic survey

AIM:To determine the basic demographic features of colorectal cancer (CRC) in five hospitals located in four different areas of Guangdong Province,China.METHODS:A review of patient records from 1986 to 2006 from five hospitals was conducted. Patient data was obtained,including age,gender,location of le-sions,staging and histological type of CRC. The Chi-square test was used to assess differences in rates and a significance level of 0.05 was used. Univariate com-parisons were made via Fisher's exact tests.RESULTS:Analysis was carried out on 8172 CRC patents,6.1% (499/8172) of the patients were aged ≤ 30 years. The peak incidence was between the ages 61-70 years (27.8%). The mean age at CRC diagnosis increased from 52 years (1986-1988) to 60 years(2004-2006) and the proportion of young CRC patients decreased from 8.0% to 5.9% over the same period. Of 8172 lesions,4434 (54.3%) were located in rectum and 3738 (45.7%) in colon. The incidence of rectal cancer decreased significantly from 59.4% (1989-1991) to 51.8% (2004-2006) and right sided colon cancer increased from 40.6% to 48.2%. The mean age,ana-tomic distribution,histological type and differentiation degree were significantly different among the four geographical areas (P < 0.05).CONCLUSION:The hospitalization rate for CRC has increased in Guangdong in recent years. The characteristics of CRC from the five hospitals located in the four different areas of Guangdong Province are also different. Further studies are needed to assess more recent trend in the incidence and prevalence of CRC as well as the respective roles of genetic and environ-mental factors in CRC.

Remission induction and maintenance effect of probiotics on ulcerative colitis: A meta-analysis

AIM:To evaluate the induction of remission and main-tenance effects of probiotics for ulcerative colitis.METHODS: Information was retrieved from MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. The induction of remission and promotion of mainte-nance were compared between probiotics treatment and non-probiotics treatment in ulcerative colitis.RESULTS: Thirteen randomized controlled studies met the selection criteria. Seven studies evaluated the remission rate, and eight studies estimated the recur-rence rate; two studies evaluated both remission and recurrence rates. Compared with the non-probiotics group, the remission rate for ulcerative colitis patients who received probiotics was 1.35 (95% CI: 0.98-1.85). Compared with the placebo group, the remission rate of ulcerative colitis who received probiotics was 2.00 (95% CI: 1.35-2.96). During the course of treatment, in patients who received probiotics for less than 12 mo compared with the group treated by non-probiotics, the remission rate of ulcerative colitis was 1.36 (95% CI: 1.07-1.73). Compared with the non-probioticsgroup, the recurrence rate of ulcerative colitis patients who received probiotics was 0.69 (95% CI: 2.47-1.01). In the mild to moderate group who received probiotics, compared to the group who did not receive probiotics, the recurrence rate was 0.25 (95% CI: 0.12-0.51). The group who received Bifidobacterium bifidum treatment had a recurrence rate of 0.25 (95% CI: 0.12-0.50) compared with the non-probiotics group.CONCLUSION: Probiotic treatment was more effec-tive than placebo in maintaining remission in ulcerative colitis.

A study of the efficacy of bacterial biofilm cleanout for gastrointestinal endoscopes

AIM:To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.METHODS:Teflon tubes were incubated in a mixture of different detergents and E. coli culture (106 CFU/mL) for 72 h at 15℃,and biofilms on the inner surface of the teflon tubes were analyzed by bacterial count and scanning electron microscopy. To evaluate the clear-ance effect of detergents,after biofilms were formed on the inner surface of Teflon tubes by 72 h lavage with E. coli culture,tubes were lavaged by enzymatic and non-enzymatic detergents at a speed of 250 mL/min,then biofilms on the inner surface were analyzed by bacterial count and scanning electron microscopy.RESULTS:Non-enzymatic detergent had a better inhi-bition function on biofilm formation than enzymatic de-tergent as it reduced bacterial burden by 2.4 log compared with the control samples (P = 0.00). Inhibition function of enzymatic detergent was not significantly different to that of control samples and reduced bac-terial burden by 0.2 log on average (P > 0.05). After lavaging at 250 mL/min for 3 min,no living bacteria were left in the tubes. Scanning electron microscopy observation showed biofi lms became very loose by the high shear force effect. CONCLUSION:Non-enzymatic detergent has a better inhibition effect on biofilm formation at room temperature. High speed pre-lavage and detergents are very important in temporal formed biofilm elimination.

Distribution of gyrA mutations in fluoroquinolone-resistant Helicobacter pylori strains

AIM:To investigate the resistance of Helicobacter pylori(H.pylori) to ciprofloxacin(CIP),levofloxacin(LVX) and moxifloxacin(MOX) in the Beijing area and to elucidate the resistance mechanisms.METHODS:Seventy-nine H.pylori clinical strains,isolated from patients who had undergone upper gastrointestinal endoscopy in Peking University First Hospital from 2007 to 2009,were tested for their susceptibility to CIP,LVX and MOX using the E-test method.H.pylori strain 26695 was included in the susceptibility testing as a control strain.According to the minimal inhibitory concentration(MIC) values,a strain was classified as resistant to CIP,LVX or MOX when the MIC was > 1 μg/mL.We amplified by polymerase chain reaction(PCR) and sequenced the quinolone resistance-determining regions of the gyrA and gyrB genes from 29 quinolone-resistant and 16 quinolone-susceptible H.pylori strains selected at random.RESULTS:In this study,the resistance rates of H.pylori to CIP,LVX or MOX were 55.7%(44/79),and the primary resistance rates were 26.6%(21/79).Patients with secondary resistance had received LVX in previous eradication treatments,but not MOX or CIP.Forty-five strains,including 29 CIP,LVX or MOX-resistant strains(MIC:1.5-32 μg/mL) and 16 susceptible strains,were selected randomly from the 79 strains and used in PCR analysis.Among these 45 strains,27 resistant strains had mutations in the gyrA gene,including 11 strains with mutations corresponding to Asp-91(MIC:2-32 μg/mL),one of which also had a mutation corresponding to Val-150,and 16 strains had mutations at Asn-87(MIC:4-32 μg/mL),three of which also had mutations corresponding to Arg-140 or Val-150.In addition,Arg-140,Val-150 or Ala-97 mutations were separately detected in three susceptible strains.Analysis of the gyrB gene showed that one strain of low resistance had a mutation corresponding to Ser-457 that coexisted with an Asp-91 mutation.There was a significant difference in the occurrence of mutations in the gyrA gene between CIP,LVX and MOX-resistant and-susceptible strains(P < 0.05),but 2 resistant strains were found to possess no quinolone resistance-determining region mutations.CONCLUSION:Resistance is primarily mediated through point mutations in gyrA.Whether other mechanisms are responsible for resistance in strains without mutations in the QRDR should be detected.

Emodin enhances alveolar epithelial barrier function in rats with experimental acute pancreatitis

AIM: To investigate the effect of emodin on expression of claudin4, claudin5 and occludin, as well as the alveolar epithelial barrier in rats with pancreatitis induced by sodium taurocholate. METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 3 h after induction of acute pancreatitis. Rats from sham operation group and acute pancreatitis group were injected with normal saline (an equivalent volume as emodin) at the same time point. Samples of lung and serum were obtained 6 h after drug administration. Pulmonary morphology was examined with HE staining. Pulmonary edema was estimated by measuring water content in lung tissue samples. Tumor necrosis factorα (TNFα) and interleukin6 (IL6) level were measured by enzymelinked immunospecific assay. Serum amylase and pulmonary myeloperoxidase (MPO) activity were detected by spectrophotometry. Alveolar epithelial barrier was assessed by pulmonary dye extravasation. Expression of claudin4, claudin5 and occludin in lung tissue samples was examined by immunohistology, quantitative realtime reverse transcription polymerase chain reaction and Western blotting analysis, respectively.RESULTS: Pancreatitis-associated lung injury was char-acterized by pulmonary edema, leukocyte infiltration, alveolar collapse, and elevated serum amylase level. The pulmonary damage, pulmonary pathological scores, serum amylase and MPO activity, TNF-α and IL-6 levels, and wet/dry ratio were decreased in rats after treatment with emodin. Immunostaining of claudin-4, claudin-5 and occludin was detected in lung tissue samples from rats in sham operation group, which was distributed in alveolar epithelium, vascular endothelium, and bron-chial epithelium, respectively. The mRNA and protein expression levels of claudin-4, claudin-5 and occludin in lung tissue samples were markedly decreased, the expression level of claudin-4, claudin-5 and occluding was increased, and the pulmonary dye extravasation was reduced in lung tissue samples from rats with acute pancreatitis after treatment with emodin.CONCLUSION: Emodin attenuates pulmonary edema and inflammation, enhances alveolar epithelial barrier function, and promotes expression of claudin-4, claudin-5 and occludin in lung tissue samples from rats with acute pancreatitis.

Establishment of a human hepatoma multidrug resistant cell line in vitro

AIM:To establish a multidrug-resistant hepatoma cell line(SK-Hep-1),and to investigate its biological characteristics.METHODS:A highly invasive SK-Hep-1 cell line of human hepatocellular carcinoma,also known as malignant hepatoma was incubated with a high concentration of cisplatin(CDDP) to establish a CDDP-resistant cell subline(SK-Hep-1/CDDP).The 50% inhibitory dose(IC50) values and the resistance indexes [(IC50 SK-Hep-1/CDDP)/(IC50 SK-Hep-1)] for other chemotherapeutic agents and the growth curve of cells were all evaluated using cell counting kit-8 assays.The distribution of the cell cycles were detected by flow cytometry.Expression of acquired multidrug resistance P-glycoprotein(MDR1,ABCB1) and multidrug resistance-associated protein 1(MRP1,ABCC1) was compared with that in parent cells by Western blotting and immunofluorescence combined with laser scanning confocal microscopy.RESULTS:The SK-Hep-1/CDDP cells(IC50 = 70.61 ± 1.06 μg/mL) was 13.76 times more resistant to CDDP than the SK-Hep-1 cells(IC50 = 5.13 ± 0.09 μg/mL),and CDDP-resistant cells also demonstrated cross-resistance to many anti-tumor agents such as doxorubicin,5-fluorouracil and vincristine.Similar morphologies were determined in both SK-Hep-1 and SK-Hep-1/CDDP groups.The cell cycle distribution of the SK-Hep-1/CDDP cell line exhibited a significantly increased percentage of cells in S(42.2% ± 2.65% vs 27.91% ± 2.16%,P < 0.01) and G2/M(20.67% ± 5.69% vs 12.14% ± 3.36%,P < 0.01) phases in comparison with SK-Hep-1 cells,while the percentage of cells in the G0/G1 phase decreased(37.5% ± 5.05% vs 59.83% ± 3.28%,P < 0.01).The levels of MDR1 and MRP1 were overexpressed in the SK-Hep-1/CDDP cells exhibiting the MDR phenotype.CONCLUSION:Multiple drug resistance of multiple drugs in the human hepatoma cell line SK-Hep-1/CDDP was closely related to the overexpression of MDR1 and MRP1.

Study of T-lymphocyte subsets,nitric oxide,hexosamine and Helicobacter pylori infection in patients with chronic gastric diseases

Chronic gastritis ( CG ) and peptic ulcer ( PU ) are frequently-occurring diseases. It is now well recognized that Helicobacter pylori (Hp) is a major factor that leads to CG and PU[1-8] In order to study the relationship among T lymphocyte subsets, NO, Hexosamine and Hp infection in patients with chronic gastric diseases, the levelsof blood T lymphocyte subsets, plasma NO and hexosamine in gastric mucosa were measured respectively in 30 patients with CG and 32 patients of PU + CG.

Effect of domperidone therapy on nocturnal dyspeptic symptoms of functional dyspepsia patients

AIM:To investigate the incidence of nocturnal dyspeptic symptoms in patients with functional dyspepsia(FD) and whether prokinetic drugs can alleviate them. METHODS:Eighty-five consecutive Chinese patients with FD were included in this study.One week after single-blinded placebo run-in treatment,baseline nocturnal intragastric pH,bile reflux and nocturnal dyspeptic symptoms of eligible patients,including epigastric pain or discomfort,abdominal distention and belching, were investigated with questionnaires.Patients exhibiting nocturnal dyspeptic symptoms were randomly and double-blindly assigned to domperidone group or placebo group.Nocturnal intragastric pH and percentage of duodenogastric bile reflux time were determined after treatment. RESULTS:Of the 85 FD patients,2 females withoutnocturnal symptoms,who responded to placebo run-in treatment,were excluded from the study,30(36.1%) exhibited nocturnal dyspeptic symptoms with increased duodenogastric bile reflux time(intragastric bilirubin absorbance>0.14)and mean gastric pH(confirming the existence of bile reflux)(P=0.021,0.023) at night were included in the study.Of these 30 patients,21(70%)had overt nocturnal duodenogastric bile reflux,which was significantly higher than that of those without nocturnal symptoms(P=0.026).The 30 patients were allocated to domperidone group or placebo group(n=15).The nocturnal duodenogastric bile reflux and gastric pH were significantly decreased after domperidone treatment(P=0.015,0.021).The severity score of nocturnal dyspeptic symptoms was also significantly decreased after domperidone treatment (P=0.010,0.015,0.026),which was positively correlated with the reduced nocturnal bile reflux or gastric pH(r=0.736,0.784,0.753 or r=0.679,0.715,0.697, P=0.039,0.036,0.037 or P=0.043,0.039,0.040). CONCLUSION:A subgroup of Chinese FD patients show overt nocturnal dyspeptic symptoms,which may be correlated with the excessive nocturnal duodenogastric bile reflux.Domperidone therapy can alleviate these symptoms.

Combined MELD and blood lipid level in evaluating the prognosis of decompensated cirrhosis

AIM: To evaluate the prognostic value of the combined model for end-stage liver disease (MELD) and blood lipid level in patients with decompensated cirrhosis. METHODS: A total of 198 patients with decompensated cirrhosis were enrolled into the study. The values of triglyceride (TG), cholesterol (TC), high density lipoproteins (HDL) and low density lipoprotein (LDL) of each patient on the fi rst day of admission were retrieved from the medical records, and MELD was calculated. All the patients were followed up for 1 year. The relationship between the change of blood lipid level and the value of MELD score was studied by analysis of variance. The prognostic factors were screened by multivariate Cox proportional hazard model. Draw Kaplan-Meier survival curves were drawn. RESULTS: Forty-f ive patients died within 3 mo and 83 patients died within 1 year. The levels of TG, TC, HDL and LDL of the death group were all lower than those of the survivors. The serum TG, TC, HDL and LDL levels were lowered with the increase of the MELD score. Multivariate Cox proportional hazard model showed that MELD ≥18 and TC ≤2.8 mmol/L were independent risk factors for prognosis of decompensated cirrhosis. Survival analysis showed that MELD ≥18 combined with TC ≤ 2.8 mmol/L can clearly discriminate between the patients who would survive and die in 1 year. CONCLUSION: MELD ≥18 and TC ≤2.8 mmol/L are two important indexes to predict the prognosis of patients with decompensated cirrhosis. Their combination can effectively predict the long-term prognosis of patients with decompensated cirrhosis.

Protective effects of MCP-1 inhibitor on a rat model of severe acute pancreatitis

BACKGROUND: Chemokines and their receptors play key roles in the pathogenesis of acute pancreatitis. This study aimed to establish a rat model of severe acute pancreatitis (SAP) for investigating monocyte chemotactic protein-1 (MCP-1) expression in the pathogenesis of the disease. We assessed the effects of the inhibitor of MCP-1, Bindarit, on SAP and explored the mechanisms underlying SAP. METHODS: Seventy-two Sprague-Dawley rats were randomly divided into a saline control group (group S), an SAP group (group P), and a Bindarit group (group T). The SAP model was induced by retrograde infusion of 4% sodium taurocholate into the bilio-pancreatic duct. Based on the SAP model, Bindarit was injected intraperitoneally in group T, and 0.5% methyl cellulose was injected intraperitoneally in groups S and P. In group S, saline was retrogradely infused into the bilpancreatic duct. Serum amylase levels and the histological changes in the pancreas were assessed at different time-points in each group. Expression of MCP-1 in serum was measured by enzyme-linked immunoadsorbent assay (ELISA). MCP-1 protein and mRNA expression levels were detected by immunohistochemistry, Western blotting, and semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Serum amylase levels in groups P and T were higher than those in group S. Serum amylase levels were significantly lower in group T than in group P at 6 and 12 hours after operation. The levels of MCP-1 in serum at 6 and 12 hours after operation in group P were significantly higher than in group S, and significantly lower in group T than in group P at 6 and 12 hours after operation. The pathological damage in the pancreas was milder in group T than in group P. MCP-1 protein and mRNA expression levels in the pancreas were higher in groups P and T than in group S. These expression levels were positively correlated with the pathological damage of pancreatic tissues. The activity of MCP-1 in group T was significantly lower than in group P. CONCLUSION: MCP-1 may play important roles in the pathogenesis of SAP. The data suggest that Bindarit ameliorates SAP by inhibiting the activity of MCP-1 in vivo. (Hepatobiliary Pancreat Dis Int 2010; 9: 201-207)

Double-balloon enteroscopy for obscure gastrointestinal bleeding: A single center experience in China

AIM: To evaluate the diagnostic value of double-balloon enteroscopy (DBE) for obscure gastrointestinal bleeding (OGIB). METHODS: The data about 75 OGIB patients who underwent DBE in January 2007-June 2009 in our hospital were retrospectively analyzed. RESULTS: DBE was successfully performed in all 75 patients without complication. Of the 75 patients, 44 (58.7%) had positive DBE findings, 22 had negative DBE findings but had potential bleeding at surgery and capsule endoscopy, etc . These 66 patients were finally diagnosed as OGIB which was most commonly caused by small bowel tumor (28.0%), angiodysplasia (18.7%) and Crohn’s disease (10.7%). Lesions occurred more frequently in proximal small bowel than in distal small bowel (49.3% vs 33.3%, P = 0.047). CONCLUSION: DBE is a safe, effective and accurate procedure for the diagnosis of OGIB.

Influence of efflux pump inhibitors on the multidrug resistance of Helicobacter pylori

AIM:To evaluate the effect of efflux pump inhibitors (EPIs) on multidrug resistance of Helicobacter pylori (H. pylori).METHODS: H. pylori strains were isolated and cultured on Brucella agar plates with 10% sheep's blood. The multidrug resistant (MDR) H. pylori were obtained with the inducer chloramphenicol by repeated doubling of the concentration until no colony was seen, then the susceptibilities of the MDR strains and their parents to 9 antibiotics were assessed with agar dilution tests. The present study included periods before and after the advent of the EPIs, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), reserpine and pantoprazole), and the minimum inhibitory concentrations (MICs) were determined accordingly. In the same way, the effects of 5 proton pump inhibitors (PPIs), used in treatment of H. pylori infection, on MICs of antibiotics were evaluated.RESULTS: Four strains of MDR H. pylori were induced successfully, and the antibiotic susceptibilities of MDR strains were partly restored by CCCP and pantoprazole, but there was little effect of reserpine. Rabeprazole was the most effective of the 5 PPIs which could decrease the MICs of antibiotics for MDR H. pylori significantly.CONCLUSION: In vitro, some EPIs can strengthen the activities of different antibiotics which are the putative substrates of the efflux pump system in H. pylori.

64-row multidetector computed tomography portal venography of gastric variceal collateral circulation

AIM:To study characteristics of collateral circulation of gastric varices (GVs) with 64-row multidetector computer tomography portal venography (MDCTPV).METHODS:64-row MDCTPV with a slice thickness of 0.625 mm and a scanning field from 2 cm above the tracheal bifurcation to the lower edge of the kidney was performed in 86 patients with GVS diagnosed by endoscopy. The computed tomography protocol included unenhanced,arterial and portal vein phases. The MDCTPV was performed on an AW4.3 workstation. GVs were classified into three types according to Sarin's Classification. The afferent and efferent veins of each type of GV were observed.RESULTS:The afferent venous drainage originated mostly from the left gastric vein alone (LGV) (28/86,32.59%),or the LGV more than the posterior gastric vein/short gastric vein [LGV > posterior gastric vein/short gastric vein (PGV/SGV)] (22/86,25.58%),as seen by MDCTPV. The most common efferent venousdrainage was via the azygos vein to the superior vena cava (53/86,61.63%),or via the gastric/splenorenal shunt (37/86,43.02%) or inferior phrenic vein (8/86,9.30%) to the inferior vena cava. In patients with gastroesophageal varices type 1,the afferent venous drainage of GV mainly originated from the LGV or LGV > PGV/SGV (43/48,89.58%),and the efferent venous drainage was mainly via the azygos vein to the super vena cava (43/48,89.58%),as well as via the gastric/splenorenal shunt (8/48,16.67%) or inferior phrenic vein (3/48,6.25%) to the inferior vena cava. In patients with gastroesophageal varices type 2,the afferent venous drainage of the GV mostly came from the PGV/SGV more than the LGV (PGV/SGV > LGV) (8/16,50%),and the efferent venous drainage was via the azygos vein (10/16,62.50%) and gastric/splenorenal shunt (9/16,56.25%). In patients with isolated gastric varices,the main afferent venous drainage was via the PGV/SGV alone (16/22,72.73%),and the efferent venous drainage was mainly via the gastric/splenorenal shunt (20/22,90.91%),as well as the inferior phrenic vein (3/23) to the inferior vena cava. CONCLUSION:MDCTPV can clearly display the afferent and efferent veins of all types of GV,and it could provide useful reference information for the clinical management of GV bleeding.