Role of Renin-Angiotensin System in Acute Lung Injury Caused by Viral Infection.

The renin-angiotensin system (RAS) is the most important regulatory system of electrolyte homeostasis and blood pressure and acts through angiotensin-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II type 1 (AT1) receptor axis and angiotensin-converting enzyme 2 (ACE2)/angiotensin (1-7)/MAS receptor axis. RAS dysfunction is related to the occurrence and development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) and causes a serious prognosis and even death. ALI/ARDS can be induced by various ways, one of which is viral infections, such as SARS-CoV, SARS-CoV-2, H5N1, H7N9, and EV71. This article reviews the specific mechanism on how RAS dysfunction affects ALI/ARDs caused by viral infections. SARS-CoV and SARS-CoV-2 enter the host cells by binding with ACE2. H5N1 and H7N9 avian influenza viruses reduce the ACE2 level in the body, and EV71 increases Ang II concentration. Treatment with angiotensin-converting enzyme inhibitor and angiotensin AT1 receptor blocker can alleviate ALI/ARDS symptoms. This review provides suggestions for the treatment of lung injury caused by viral infections.

Prevalence and risk factors of chronic kidney disease and diabetic kidney disease in a central Chinese urban population: a cross-sectional survey.

BACKGROUND: This study was conducted to evaluate and update the current prevalence of and risk factors for chronic kidney disease (CKD) and diabetic kidney disease (DKD) in a central Chinese urban population. METHODS: From December 2017 to June 2018, a total of 5231 subjects were randomly enrolled from 3 communities in 3 districts of Zhengzhou. CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min.1.73m2 or urinary albumin to creatinine ratio ≥ 30 mg/g (albuminuria). Diabetic subjects with systolic blood pressure > 140 mmHg, albuminuria or an eGFR less than 60 mL/min/1.73 m2 were classified as having DKD. Participants completed a questionnaire assessing lifestyle and relevant medical history, and blood and urine specimens were taken. Serum creatinine, uric acid, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein and urinary albumin were assessed. The age- and sex-adjusted prevalences of CKD and DKD were calculated, and risk factors associated with the presence of reduced eGFR, albuminuria, DKD, severity of albuminuria and progression of reduced renal function were analyzed by binary and ordinal logistic regression. RESULTS: The overall adjusted prevalence of CKD was 16.8% (15.8-17.8%) and that of DKD was 3.5% (3.0-4.0%). Decreased renal function was detected in 132 participants (2.9, 95% confidence interval [CI]: 2.5-3.2%), whereas albuminuria was found in 858 participants (14.9, 95% CI: 13.9-15.9%). In all participants with diabetes, the prevalence of reduced eGFR was 6.3% (95% CI = 3.9-8.6%) and that of albuminuria was 45.3% (95% CI = 40.4-50.1%). The overall prevalence of CKD in participants with diabetes was 48.0% (95% CI = 43.1-52.9%). The results of the binary and ordinal logistic regression indicated that the factors independently associated with a higher risk of reduced eGFR and albuminuria were older age, sex, smoking, alcohol consumption, overweight, obesity, diabetes, hypertension, dyslipidemia and hyperuricemia. CONCLUSIONS: Our study shows the current prevalence of CKD and DKD in residents of Central China. The high prevalence suggests an urgent need to implement interventions to relieve the high burden of CKD and DKD in China.

Emergence and mechanism of carbapenem-resistant Escherichia coli in Henan, China, 2014.

The emergence and dissemination of carbapenem-resistant Escherichia coli (E. coli) strains is a main risk for global public health, but little is known of carbapenemase producing E. coli in Henan, China. The study was undertaken to investigate the prevalence and mechanism of carbapenem-resistant E. coli strains in a hospital in Xinxiang, Henan, China, 2014. A total of 5 carbapenemase-producing E. coli strains were screened from 1014 isolates. We found that they were all resistant to meropenem and imipenem. Amikacin showed the best sensitivity, with gentamicin coming up next. The positive rate of blaNDM was 80% (4/5). The sequencing results showed that two isolates belonged to blaNDM-1 whereas other 2 isolates carried the blaNDM-5. Other carbapenemase genes including blaIMP,blaVIM, blaKPC and blaOXA-48 were not detected. The blaCTX-M-15,blaTEM-1,sul2, aad, and aac(6")-Ib-cr were also detected. MLST analysis showed that NDM-producing E. coli were sporadic. Conjugation test indicated blaNDM could be transferred. In conclusion, the blaNDM was the principal resistance mechanism of carbapenem-resistant E. coli in the hospital, Henan, China.

Pathogenic mechanisms of the oncoprotein CagA in H. pylori-induced gastric cancer (Review).

Infection with Helicobacter pylori is the strongest risk factor for the development of chronic gastritis, gastric ulcer and gastric carcinoma. The majority of the H. pylori-infected population remains asymptomatic, and only 1% of individuals may progress to gastric cancer. The clinical outcomes caused by H. pylori infection are considered to be associated with bacterial virulence, genetic polymorphism of hosts as well as environmental factors. Most H. pylori strains possess a cytotoxin-associated gene (cag) pathogenicity island (cagPAI), encoding a 120-140 kDa CagA protein, which is the most important bacterial oncoprotein. CagA is translocated into host cells via T4SS system and affects the expression of signaling proteins in a phosphorylation-dependent and independent manner. Thus, this review summarizes the results of relevant studies, discusses the pathogenesis of CagA-mediated gastric cancer.

Role of Helicobacter pylori infection in pathogenesis of gastric carcinoma.

Gastric cancer (GC) is one of the most common carcinoma and the second leading cause of cancer-related deaths worldwide. Helicobacter pylori (H. pylori) infection causes a series of precancerous lesions like gastritis, atrophy, intestinal metaplasia and dysplasia, and is the strongest known risk factor for GC, as supported by epidemiological, preclinical and clinical studies. However, the mechanism of H. pylori developing gastric carcinoma has not been well defined. Among infected individuals, approximately 10% develop severe gastric lesions such as peptic ulcer disease, 1%-3% progresses to GC. The outcomes of H. pylori infection are determined by bacterial virulence, genetic polymorphism of hosts as well as environmental factors. It is important to gain further understanding of the pathogenesis of H. pylori infection for developing more effective treatments for this common but deadly malignancy. The recent findings on the bacterial virulence factors, effects of H. pylori on epithelial cells, genetic polymorphism of both the bacterium and its host, and the environmental factors for GC are discussed with focus on the role of H. pylori in gastric carcinogenesis in this review.

Incidence, survival and prevalence of esophageal and gastric cancer in Linzhou city from 2003 to 2009.

This study describes recent trends in incidence, survival and prevalence of subgroups of esophageal and gastric cancer in Linzhou city between 2003 and 2009. Data of esophageal and gastric cancer for the period of interest were extracted from the Linzhou Cancer Registry. Using information on tumor morphology or anatomical site, data were divided into six groups; esophageal squamous cell carcinoma, esophageal adenocarcinoma, other and unspecified types of esophageal cancer, and cardia, non-cardia, and unspecified anatomical site of stomach cancer. Incidence, survival and prevalence rates for each of the six cancer groups were calculated. The majority of esophageal cancers were squamous cell carcinomas (82%). Cardiac cancer was the major gastric cancer group (64%). The incidence of esophageal squamous cell carcinoma and gastric cardiac cancer increased between 2003 and 2009. Both esophageal and gastric cancer had a higher incidence in males compared with females. Overall survival was poor in all sub-groups with 1 year survival ranging from 45.9 to 65.6% and 5 year survival ranging from 14.7 to 30.5%. Prevalence of esophageal squamous cell carcinoma and gastric cardiac cancer was high (accounting for 80% overall). An increased focus on prevention and early diagnosis, especially in esophageal squamous cell carcinoma and gastric cardiac cancer, is required.

Prognostic impact of cyclin D1, cyclin E and P53 on gastroenteropancreatic neuroendocrine tumours.

Conventional classifications of gastroenteropancreatic neuroendocrine tumours (GEP- NETs) are rather unsatisfactory because of the variation in survival within each subgroup. Molecular markers are being found able to predict patient outcome in more and more tumours. The aim of this study was to characterize the expression of the proteins cyclin D1, cyclin E and P53 in GEP- NETs and assess any prognostic impact. Tumor specimens from 68 patients with a complete follow-up were studied immunohistochemically for cyclin D1, cyclin E and P53 expression. High cyclin D1 and cyclin E immunostaining (≥ 5% positive nuclei) was found in 48 (71%) and 24 (35%) cases, and high P53 staining (≥ 10% positive nuclei) in 33 (49%) . High expression of P53 was more common in gastric neuroendocrine tumors and related to malignant behavior, being associate with a worse prognosis on univariate analysis (RR=1.9, 95%CI=1.1-3.2). High expression of cyclin E was significantly associated with shorter survival in the univariate analysis (RR=2.0, 95%CI=1.2-3.6) and multivariate analysis (RR=2.1, 95%CI=1.1-4.0). We found no significant correlation between the expression of cyclin D1 and any clinicopathological variables. Our study indicated a prognostic relevance for cyclin E and P53 immunoreactivity. Cyclin E may be an independent prognostic factor from the 2010 WHO Classification which should be evaluated in further studies.

How often are ineffective interventions still used in clinical practice? A cross-sectional survey of 6,272 clinicians in China.

BACKGROUND: The World Health Organization reported in 2011 that irrational use of medicines was a serious global problem that is wasteful and harmful. The worst is use of ineffective or harmful interventions which should not be used at all. However, little is known about the changes that 20 years of evidence-based medicine has made particularly in reducing use of ineffective interventions. We surveyed clinicians in China to show how often ineffective interventions were still used in practice. METHODS: 3,246 clinicians from 24 tertiary hospitals were surveyed in person and another 3,063 through an online survey between 2006-2007. The main outcomes are prescription by a clinician, and use in a patient of, an ineffective intervention and of a matched effective intervention in patients with the same disease. 129 ineffective interventions for 68 diseases were identified from the BMJ Clinical Evidence and included in the survey. One effective intervention was identified for each disease and a total of 68 effective interventions were thus also included. The frequency of use of effective interventions was used as a reference for that of ineffective intervention. RESULTS: The mean prescription rate by clinicians is 59.0% (95% confidence interval (95% CI): 58.6% to 59.4%) and 81.0% (95% CI: 80.6% to 81.4%) respectively for ineffective and effective interventions. The mean frequency of use in patients is 31.2% (95% CI: 30.8% to 31.6%) and 56.4% (95% CI: 56.0% to 56.8%) for ineffective and effective interventions respectively. The relative reduction in use of ineffective interventions as compared with that of matched effective interventions is 27.2% (95% CI: 27.0% to 27.4%) and 44.7% (95% CI: 44.3% to 45.1%) for clinician's prescription and use in patients respectively. 8.6% ineffective interventions were still routinely used in practice. CONCLUSIONS: Ineffective interventions were still commonly used. Efforts are necessary to further reduce and eventually eliminate ineffective interventions from practice.

Transgenic peanut (Arachis hypogaea L.) expressing the urease subunit B gene of Helicobacter pylori.

Helicobacter pylori (H. pylori) has been identified as the main pathogenic factors of chronic gastritis and peptic ulcer, and the Class I carcinogen of gastric cancer by WHO. Vaccine has become the most effective measure to prevent and cure H. pylori infection. The UreB is the most effective and common immunogen of all strains of H. pylori and may stimulate the immunoresponse protecting the human body against the challenge of H. pylori. UreB antigen gene was cloned into the binary vector pBI121 which contains a seed-specific promoter Oleosin of peanut and a kanamycin resistance gene, and then UreB gene was transformed into peanut embryo leaflets by Agrobacter-mediated method. The putative transgenic plants were examined for the presence of UreB in the nuclear genome of peanut plants by PCR analysis. Expression of UreB gene in plants was identified by RT-PCR and Western blot analysis. These results suggest that the UreB transgenic peanut can be potentially used as an edible vaccine for controlling H. pylori.

Atypical class 1 integron coexists with class 1 and class 2 integrons in multi-drug resistant Shigella flexneri isolates from China.

The antimicrobial resistance and the character of integrons were determined in 58 Shigella flexneri strains isolated from China. All isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). No intI3 was detected. The typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient E. coli DH5α. The gene cassettes of typical class 1 integrons dfrA17-aadA5 and dfrA12-orfF-aadA2 were detected in 54 strains (93.1%) and 1 strain, respectively. Atypical class 1 integrons located on the chromosome with gene cassettes bla (oxa-30)-aadA1 were detected in 55 isolates (94.8%). All the intI2 positive isolates carried gene cassettes dfrA1-sat1-aadA1. To our knowledge, this is the first report that atypical and typical class 1 integrons coexisted with class 2 integron in multi-drug resistant S. flexneri strains.

Mutation of iceA in Helicobacter pylori compromised IL-8 induction from human gastric epithelial cells.

IceA of Helicobacter pylori (H. pylori) has been suggested as a virulence factor for the bacteria, but its pathogenic role remains unelucidated. Here, we examined the effect of iceA mutation on the secretion of IL-8 by human gastric epithelial cells. We also investigated whether the changes in IL-8 production caused by iceA mutation were associated with impaired adherence of H. pylori to the epithelial cells or with impaired apoptosis of these cells. The iceA mutant strain was constructed from wildtype H. pylori strain by insertional mutagenesis of iceA. The human gastric epithelial cells SGC7901 were infected with wildtype or mutant H. pylori for appropriate lengths of time. The adherence of the bacteria to the epithelial cells was examined by fluorescent microscopy using an anti-H. pylori antibody and flow cytometry. The apoptosis of the epithelial cells was studied by annexin-V staining and flow cytometry. The production of IL-8 by SGC 7901 cells was determined by ELISA. We found that iceA mutation was associated with significantly impaired production of IL-8 from the epithelial cells, which was not due to impaired adherence by the bacteria to the epithelial cells as wildtype and mutant H. pylori exhibited similar levels of binding to the epithelial cells. Furthermore, inactivation of iceA did not affect the apoptotic cell death of SGC7901. Our findings indicate that iceA may contribute to the pathogenicity of H. pylori by modulating the production of IL-8 by host epithelial cells.

Mutation of cytotoxin-associated gene A affects expressions of antioxidant proteins of Helicobacter pylori.

AIM: To determine if disruption of the cagA gene of Helicobacter pylori (H pylori) has an effect on the expression of other proteins at proteome level. METHODS: Construction of a cagA knock out mutant Hp27_Delta cagA (cagA(-)) via homologous recombination with the wild-type strain Hp27 (cagA(+)) as a recipient was performed. The method of sonication-urea-CHAPS-DTT was employed to extract bacterial proteins from both strains. Soluble proteins were analyzed by two-dimensional electrophoresis (2-DE). Images of 2-DE gels were digitalized and analyzed. Only spots that had a statistical significance in differential expression were selected and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Biological information was used to search protein database and identify the biological function of proteins. RESULTS: The proteome expressions between wild-type strain and isogenic mutant with the cagA gene knocked-out were compared. Five protein spots with high abundance in bacteria proteins of wild-type strains, down-regulated or absently expressed in bacteria proteins of mutants, were identified and analyzed. From a quantitative point of view, the identified proteins are related to the cagA gene and important antioxidant proteins of H pylori, including alkyl hydroperoxide reductase (Ahp), superoxide dismutase (SOD) and modulator of drug activity (Mda66), respectively, suggesting that cagA is important to maintain the normal activity of antioxidative stress and ensure H pylori persistent colonization in the host. CONCLUSION: cagA gene is relevant to the expressions of antioxidant proteins of H pylori, which may be a novel mechanism involved in H pylori cagA pathogenesis.

[Construction, expression and purification of UreB-Omp11 fusion protein of Helicobacter pylori and its immunocompetence].

AIM: To construct H.pylori vaccine candidate strain expressing UreB-Omp11 recombinant fusion protein of H.pylori. To express and purify the fusion protein UreB-Omp11 and to determine its immunocompetence. METHODS: The two genes were amplified by PCR, and the fusion gene ureB-omp11 was amplified by over lap extension PCR and then cloned into the fusion expression vector pET30a(+), pET28a(+) and pMAL-c2X. The appropriate expression system was selected, and the recombinant UreB-Omp11 fusion protein was expressed and indentfied by SDS-PAGE and Western blot analysis. Then the fusion protein was purified by MBP affinity chromatography and the purity was indentfied by SDS-PAGE. Then the fusion protein was immunized to mice. The immunized mice sera were analyzed by Western blot with purified fusion protein. RESULTS: The ureB-omp11 fusion gene was correctly insected into pET30a(+) and confirmed by Enzyme digestion and sequencing analysis; Results in SDS-PAGE and optical density scanning demonstrated that this fusion protein MBP-UreB-Omp11 was expressed in the recombinant strain of E.coli TB1(pMAL-ureB-omp11). The fusion protein UreB-Omp11 was recognized by the mice sera immunized by H.pylori, the human sera infected with H.pylori and The purity of fusion protein was 90% after purification. The fusion protein purified could be recognized by corresponding antibody of mice sera immunized by this fusion piotein, This fusion protein has strong immunoantigenicity and immunoreactivity. CONCLUSION: The prokaryotic expression system TB1 (pMAL-c2X-ureB-omp11) was successfully constructed and selected. The results obtained lay the foundation for research on development of protein and DNA vaccine of Hp.

[The mechanisms and effects of lutein on inducing the cell differentiation of human esophagus cancer EC9706].

OBJECTIVE: The purpose of the study was to explore the effects and molecular mechanisms of lutein on the differentiation of esophagus cancer EC9706 cell. METHODS: EC9706 cells were seeded in 1640 medium before the addition of test compounds. The respective test compound was added in fresh medium and the control cell received the vehicle (DMSO) or Fluorouracil. The proliferation and cell cycle of EC9706 were determined by MTT assay and flow cytometry, respectively. The change in cytomorphology was investigated by using HE staining. Proliferation and differentiation cells were checked and observed by methyl green-pyronine staining. The protein expression of cyclin D1 was detected by immunohistochemistry. RESULTS: Compared with the DMSO control group, the proliferation of the EC9706 cells treated with lutein (100 microg/mL and 150 microg/mL) could markedly be decreased and the cell cycle was blocked at G0/G1 phage which caused significant changes in the cytomorphology of EC9706 cell line, and the cell malignant degree tended to drop down, the protein expression of cyclin D1 was also down-regulated significantly. CONCLUSION: Lutein can inhibit the proliferation of EC9706 cell, and promote the cancer cell differentiation. cyclin D1 may be involved in cell proliferation and differentiation events in esophageal cancer EC9706 cell, which is regulated by lutein.

[Effects and mechanism of lutein on apoptosis of esophageal carcinoma EC9706 cells].

OBJECTIVE: To study the effects of lutein on apoptosis and its mechanism. METHOD: The cells of human esophageal carcinoma EC9706 were grown in RPMI medium containing 10% bovine serum and were treated with lutein at 100 microg x mL(-1) concentration. Flow cytometry was employed to investigate the effects of lutein on cell apoptosis of EC9706 cells. Histochemistry was performed to determine apoptosis-related protein expresion. RESULT: Flow cytometry analyses revealed that lutein increased EC9706 cell apoptosis ratio when treated with lutein 100 microg x mL(-1) at 96 h. Lutein decreased the expression of Bcl-2 protein and increased the expression of Bax protein in EC9706 cells. CONCLUSION: Lutein could inhibit mitosis and stimulate apoptosis of EC9706 cells. The apoptotic effect may result from the down-regulation of expression of Bcl-2 and up-regulation expression of Bax.

[Study on the level changes of obesity-associated factors and puberty-associated hormones and their relationship between obese and normal 13 years old children].

OBJECTIVE: To investigate the level changes of obesity-associated factors and puberty-associated hormones and their relationship between obese and normal Children. METHODS: The concentrations of orexins, leptin, insulin, testosterone (T), estradiol (E), luteotrophic hormone (LH), as well as follicle stimulating hormone (FSH) in blood were measured respectively in 78 cases of 13 years old obesity children and 84 normal children as a control group by the means of RIA methods. The bone ages were evaluated with "bone age standard of hundred percent scale". RESULTS: The leptin and insulin concentrations were significantly higher in obesity children as compared with the control group (P < 0.01). The concentrations of plasma orexinA were significantly lower in obesity children as compared with the control group (P < 0.01). The concentrations of T were significantly lower in obesity boys as compared with the control group (P < 0.01). The concentrations of E2 and LH were significantly higher in obesity girls as compared with the control group (P < 0.01). The bone age of the obese children was significantly older than that of the control group. Along with the bone age of children became older, the concentration of leptin and LH in blood were significantly increased. There was a positive correlation between LH and FSH in two groups of either boys and girls and so did between leptin and insulin, C-peptide, E2 (P < 0.01). In the group of normal boys, the positive correlations between LH, FSH and E2 were shown (r = 0.373, 0.314, P <0.05), and a negative correlations between leptin and T were shown as( r = -0.423, P < 0.01), a positive correlation between leptin and FSH was also shown as (r = 0.308, P < 0.05). In the control group of girls, there were positive correlations between leptin, LH and E2 (r = 0.585, 0.647, P < 0.01). Any correlations between LH, FSH T and E2 were not shown in the two obese groups of boys and girls. CONCLUSION: The leptin, orexinA, insulin, T, E2, and LH concentrations had been changed significantly in blood among those obesity children, and so as their interactions. The high level of leptin in obesity children may change the concentrations of T, E2 and LH and affect the development of puberty.

[Blood leptin, orexins and NPY levels and their relations in obese children].

OBJECTIVE: To investigate the concentration levels of leptin, orexins and neuropeptide Y (NPY) in the blood of obese children, and to analysed the relationship between these substances. METHODS: RIA methods were used to measure the concentrations of leptin, orexinA, orexinB, and NPY in the blood of 98 obese children [BMI: male (29.24 +/- 1.87) kg/mZ, female (28.12 +/- 2.30) kg/m2] and in 104 normal children [BMI: male (20.49 +/- 1.95) kg/m2, female (19.59 +/- 1.51) kg/m2] as the control group. RESULTS: The leptin concentrations in obese children [male (26.00 +/- 14.66) ng/mL; female (33.59 +/- 14.63) ng/mL] were higher than those in the control group [male (6.65 +/- 44.49) ng/mL; female [10.48 +/- 5.52) ng/mL P < 0.013]. The concentrations of plasma orexinA in obes children [male (3.23 +/- 1.86) pg/mL; female (3.38 +/- 1.80) pg/mL] were lower than those in the control group [male (4.52 +/- 1.52) pg/mL; female (4.71 +/- 1.53) pg/mL P < 0.05]; Negative correlations between leptin and NPY were noted in the obesity group (r = -0.302) and the control group (r = -0.310, P < 0.01), while the slopes in the two groups were different (control group -2.969; obese group -0.809). A positive correlation between NPY and orexinA was noted (r = 0.207, P < 0.05). The fluctuation range of orexinA in obese children was markedly narrowed when compared with that in the control group. CONCLUSION: The concentration level of peripheral orexinA and leptin in the obese and non-obese children change inversely. The obesity in children correlates with the concentrations of orexinA, leptin, NPY as well as with their interactions.

Fusion expression of Helicobacter pylori neutrophil-activating protein in E.coli.

AIM: To produce a recombinant protein rMBP-NAP, which was fusionally expressed by Helicobacter pylori (H pylori) neutrophil-activating protein (NAP) and E. coli maltose-binding protein (MBP) and to evaluate its immunoreactivity and immunogenicity. METHODS: Neutrophil-activating protein gene of H pylori (HP-napA) was subcloned from the recombinant plasmid pNEB-napA, and fused to MalE gene of expressing vector pMAL-c2x. The recombinant plasmid pMAL-c2x-napA was confirmed by restriction enzyme digestion, and then transformed into E. coli TB1. Fusion protein rMBP-NAP was induced by IPTG and identified by SDS-PAGE analysis. Soluble rMBP-NAP was purified by amylose affinity chromatography. Immunoreactivity and immunogenicity of the fusion protein were evaluated by animal experiment, Western blotting with human H pylori anti-sera. RESULTS: E.coli TB1 carrying recombinant plasmid pMAL-c2x-napA was constructed and led to a high efficiency cytosol expression of fusion protein rBMP -NAP when induced by IPTG. The molecular weight of rBMP-NAP was about 57 kD, accounting for 37.55% of the total protein in the sonicated supernatant of E. coli TB1 (pMAL-c2x-napA). The purity of the fusion protein after one-step affinity chromatography was 94% and the yield was 100 mg per liter of bacterial culture. The purified fusion protein could be specifically recognized by both human anti-sera from clinical patients with H pylori infection and rabbit sera immunized by rMBP-NAP itself. CONCLUSION: Recombinant protein rMBP-NAP might be a novel antigen for vaccine development against H pylori.

[Study on the molecular mechanism of quinolone resistance in Shigellae spp].

OBJECTIVE: To study the resistance and its mechanism of Shigellae spp. to quinolones. METHODS: Seventy-three clinical isolates were collected. Susceptibility tests of pipemidic adcid (PI), ofloxacin (OFL), norfloxacin (NOR), and ciprofloxacin (CIP) were performed in all clinical isolates and Shigella 51573. The N-terminal coding region of gyrA and parC were amplified by polymerase chain reaction (PCR) respectively. Restriction fragment length polymorphism (RFLP) was applied to all PCR procucts of gyrA and parC, and single strand conformational polymorphism analysis (SSCP) was also applied to PCR procucts of parC. RESULTS: The resistance rates for all the Shigella spp. to PI, CIP, NOR and OFL were 79.5%, 60.3%, 41.1% and 36.9%. Sixty-seven strains (91.8%) were quinolone-reduced-sensitive isolates, in which 61 strains (91%) were found carrying mutations in gyrA with 5 strains (7.5%) found carrying mutations in parC. No mutation was found in 6 quinolone-sensitive isolates or Shigella 51573. CONCLUSION: The Shigella spp. had high resistance rates to quinolones. The target gene mutations which were mainly found in gyrA and secondarily in parC, played an important role in the quinolone-resistance in Shigella spp.