基于十二杆单铰运动链的周转轮系综合方法

在将单铰运动链用于周转轮系创新综合方法的过程中,针对十二杆单铰运动链,将拓扑图分析和周转轮系创新综合的结构学原理及方法结合,得到了由十二杆单铰运动链生成的新型周转轮系的结构原型。

Curing of the Bacillus subtilis Plasmid Using Sodium Dodecyl Sulfate

Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0.008%). No growth of 24/pMX45 was observed when LB contained an SDS concentration of 0.006% or greater, and the sublethal concentration (w/v) of SDS was 0.005% with a killing rate of 99%. Samples were diluted and plated on LB agar, individual colonies were randomly picked to a selective agar medium by tooth to screen for loss of plasmid-encoded erythomycin resistance. CsCl-EtBr gradient centrifugation and plasmid DNA profile demonstrated that plasmid-cured derivative A7 has completely lost its plasmid. A7 had a shorter lag, and its cell concentration was consistently higher than that of the 24/pMX45. Elimination of the plasmid was first observed after 24/pMX45 had been treated with SDS for 8 h. The percent elimination then continued to increase until about 22 h, after which the fraction of cured cell in the population remained constant. Plasmid cured cell numbers were measured in a separate control culture of 24/pMX45 untreated by SDS. No spontaneous loss of pMX45 was observed after 24/pMX45 were incubated for 24 h and 48 h with shaking at 37 ℃.These results suggested that SDS can be used as curing agent to eliminate the plasmid of Bacillus subtilis.

Reduced secretion of epidermal growth factor in duodenal ulcer patients with Helicobacter pylori infection

AIM To investigate the concentration changes of epidermal growth factor (EGF) in duodenal ulcer patients with H. pylori infection.

Patients with Helicobacter pylori positive and negative duodenal ulcers have distinct clinical characteristics

AIM: To assess the clinical characteristics of Helicobacterpylori(H pylori) negative duodenal ulcer.METHODS: Patients with an endoscopic diagnosis of duodenal ulcer between 1996 and 2002 were included in the present study. Patients were considered to be negative for Hpylori, if both histological examination and rapid urease test of biopsy specimens were negative. A comparison was made between patients with H pyloripositive and negative duodenal ulcers.RESULTS: A total of 1 343 patients were studied. Their mean age was 54.7±0.5 years. There was a male preponderance (M:F = 2.5:1). Three hundred and ninetyeight patients (29.6%) did not have H pylori infection. The annual proportion of patients with H pylori negative duodenal ulcers increased progressively from 1996 to2002. On multivariate analysis, patients with H pylorinegative duodenal ulcer were more likely to be older, have concomitant medical problem, pre-existing malignancy, recent surgery, underlying sepsis, or taken non-steroidal anti-inflammatory drugs. In terms of clinical presentations, patients with H pylori negative duodenal ulcer were more likely to present with bleeding, multiple ulcers and larger ulcers.CONCLUSION: The proportion of patients with H pylori negative duodenal ulcers is on the rise because of a continued drop in incidence of H pylori positive duodenalulcers in recent years. Such patients have distinct clinical characteristics and it is important to ascertain the H pylori status before starting eradication therapy.

Delayed gastric emptying is associated with pylorus-preserving but not classical Whipple pancreaticoduodenectomy:A review of the literature and critical reappraisal of the implicated pathomechanism

Pylorus-preserving pancreaticoduodenectomy （PPPD） is nowadays considered the treatment of choice for periampullary tumors, namely carcinoma of the head, neck, or uncinate process of the pancreas, the ampulla of Vater, distal common bile duct or carcinoma of the peri-Vaterian duodenum. Delayed gastric emptying （DGE） comprises one of the most troublesome complications of this procedure. A search of the literature using Pubmed/IVledline was performed to identify clinical trials examining the incidence rate of DGE following standard Whipple pancreaticoduodenectomy （PD） vs PPPD. Additionally we performed a thorough in-depth analysis of the implicated pathomechanism underlying the occurrence of DGE after PPPD. In contrast to early studies, the majority of recently performed clinical trials demonstrated no significant association between the occurrence of DGE with either PD or PPPD. PD and PPPD procedures are equally effective operations regarding the postoperative occurrence of DGE. Further randomized trials are required to investigate the efficacy of a recently reported （but not yet tested in largescale studies） modification, that is, PPPD with antecolic duodenojejunostomy.

Roles of Helicobacter pylori BabA in gastroduodenal pathogenesis

Interactions between BabA and Lewis b (Leb) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are predicted, including at both transcriptional and translational levels. The formation of chimeric proteins (babA /B or babB /A chimeras) seems to play an especially important role in translational regulation. Chimeric BabB/A protein had the potential to bind Leb; however, protein production was subject to phase variation through slipped strand mispairing. The babA gene was cloned initially from strain CCUG17875, which contains a silent babA1 gene and an expressed babA2 gene. The sequence of these two genes differs only by the presence of a 10 bp deletion in the signal peptide sequence of babA1 that eliminates its translational initiation codon. However, the babA1 type deletion was found only in strain CCUG17875. A few studies evaluated BabA status by immunoblot and confirmed that BabA-positive status in Western strains was closely associated with severe clinical outcomes. BabA-positive status also was associated with the presence of other virulence factors (e.g. cagA-positive status and vacA s1 genotype). A small class of strains produced low levels of the BabA protein and lacked Leb binding activity. These were more likely to be associated with increased mucosal inflammation and severe clinical outcomes than BabA-positive strains that exhibited Leb binding activity. The underlying mechanism is unclear, and further studies will be necessary to investigate how the complex BabA-receptor network is functionally coordinated during the interaction of H pylori with the gastric mucosa.

“Rescue” regimens after Helicobacter pylori treatment failure

Helicobacter pylori (H pylori) infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After more than 20 years of experience in H pylori treatment, in my opinion, the ideal regimen to treat this infection is still to be found. Currently, apart from having to know first-line eradication regimens well, we must also be prepared to face treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final (overall) eradication rate. The choice of a "rescue" treatment depends on which treatment is used initially. If a clarithromycin- based regimen was used initially, a subsequent metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin- based combination would be a third "rescue" option. Alternatively, it has recently been suggested that levofloxacin-based rescue therapy constitutes an encouraging second-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, a quadruple regimen may be reserved as a third-line rescue option. Finally, rifabutin-based rescue therapy constitutes an encouraging empirical fourth- line strategy after multiple previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin. Even after two consecutive failures, several studies have demonstrated that H pylori eradication can finally be achieved in almost all patients if several rescue therapies are consecutively given. Therefore, the attitude in H pylori eradication therapy failure, evenafter two or more unsuccessful attempts, should be to fight and not to surrender.

Comparison of sequential and 7-,10-,14-d triple therapy for Helicobacter pylori infection

AIM:To compare the effectiveness of sequential therapy for Helicobacter pylori(H.pylori) infection with that of triple therapy of varying durations.METHODS:The 460 patients enrolled in this study had H.pylori-associated gastritis or a gastric or duodenal ulcer.After screening,H.pylori-infected patients were randomly assigned to receive either conventional triple therapy for 7,10 or 14 d,or a new 10-d sequential therapy.Each of the 4 treatment groups included 115 patients.The outcomes of eradication therapy were assessed 4 wk after treatment by the urea breath test and histology.RESULTS:The overall eradication rate was 81.0%,and eradication rates were 75.7% for 7-d conventional triple therapy,81.9% for 10-d conventional triple therapy,84.4% for 14-d conventional triple therapy,and 82.0% for 10-d sequential therapy.Neither intention-to-treat analysis nor per protocol analysis showed significant differences in eradication rates using sequential therapy or the standard triple therapy(P = 0.416 and P = 0.405,respectively).CONCLUSION:There are no significant differences between 10-d sequential eradication therapy for H.pylori and any duration of standard triple treatment in Korean patients.

Analysis of serum antibody profile against H pylori VacA and CagA antigens in Turkish patients with duodenal ulcer

AIM: To investigate the frequency of seropositivity aga- inst CagA, VacA proteins and to determine their indepen- dent effects on the development of duodenal ulcer (DU) in Turkish patients. METHODS: The study was designed as a prospective one from a tertiary referral hospital. Dyspeptic patients who were referred to our endoscopy unit for upper gas- trointestinal endoscopy between June 2003 and March 2004 and diagnosed to have DU or nonulcer dyspepsia (NUD) were included. Biopsies from the antrum and body of the stomach were taken in order to assess the current H pylori status by histology, rapid urease test and culture. Fasting sera were obtained from all patients and H pylori status of all sera was determined by IgG antibo- dies using an enzyme-linked immunosorbent assay (ELI- SA) kit. All seropositive patients were further analysed using Western blot assays detecting IgG antibodies aga- inst CagA and VacA proteins. The χ2 test was used for statistical comparison of the values and age-sex adjusted multiple regression analysis was used to determine the independent effects of CagA and VacA seropositivities on the development of DU. RESULTS: Sixty-three patients with DU and 62 patients with NUD were eligible for the final analysis. Seropositi- vity for anti-CagA was detected in 51 of 62 (82%), andin 55 of 63 (87%) patients with NUD and DU, respec- tively (p = no significance), and seropositivity for anti- VacA was found in 25 of 62 (40% ) and in 16 of 63 (25%) patients, with NUD and DU, respectively. CONCLUSION: These findings suggest that none of the- se virulence factors is associated with the development of DU in the studied Turkish patients with dyspepsia.

Precise role of H pylori in duodenal ulceration

The facts that H pylori infection is commoner in duodenal ulcer (DU) patients than in the normal population, and that eradication results in most cases being cured, have led to the belief that it causes DU. However, early cases of DU are less likely than established ones to be infected. H pylori-negative cases are usually ascribed to specific associated factors such as non-steroidal anti-inflammatory drugs (NSAIDs), Crohn’s disease, and hypergastrinaemia, but even after excluding these, several H pylori-negative cases remain and are particularly common in areas of low prevalence of H pylori infection. Moreover, this incidence of H pylori negative DU is not associated with a fall in overall DU prevalence when compared with countries with a higher H pylori prevalence. In countries with a high H pylori prevalence there are regional differences in DU prevalence, but no evidence of an overall higher prevalence of DU than in countries with a low H pylori prevalence. There is no evidence that virulence factors are predictive of clinical outcome. After healing following eradication of H pylori infection DU can still recur. Medical or surgical measures to reduce acid output can lead to long-term healing despite persistence of H pylori infection. Up to half of cases of acute DU perforation are H pylori negative. These findings lead to the conclusion that H pylori infection does not itself cause DU, but leads to resistance to healing, i.e., chronicity. This conclusion is shown not to be incompatible with the universally high prevalence of DU compared with controls.

Helicobacterpylori virulence factors in duodenal ulceration:A primary cause or a secondary infection causing chronicity

Reports from countries with a high prevalence of Helicobacter pylori （H pylori） infection do not show a proportionately high prevalence of duodenal ulceration, suggesting the possibility that H pylori cannot be a primary cause of duodenal ulceration. It has been mooted that this discrepancy might be explained by variations in the prevalence of virulence factors in different populations. The aim of this paper is to determine whether the published literature gives support to this possibility. The relevant literature was reviewed and analyzed separately for countries with a high and low prevalence of Hpylori infection and virulence factors. Although virulent strains of Hpylori were significantly more often present in patients with duodenal ulcer than without the disease in countries with a low prevalence of H pylori infection in the population, there was no difference in the prevalence of virulence factors between duodenal ulcer, nonulcer dyspepsia or normal subjects in many countries, where the prevalence of both Hpylori infection and of virulence factors was high. In these countries, the presence of virulence factors was not predictive the clinical outcome. To explain the association between virulence factors and duodenal ulcer in countries where H pylori prevalence is low, only two papers were found that give little support to the usual model proposed, namely that organisms with the virulence factors are more likely than those without them to initiate a duodenal ulcer. We offer an alternative hypothesis that suggests virulence factors are more likely to interfere with the healing of a previously produced ulcer. The presence of virulence factors only correlates with the prevalence of duodenal ulcer in countries where the prevalence of H pylori is low. There is very little evidence that virulence factors initiate duodenal ulceration, but they may be related to failure of the ulcer to heal.

Azithromycin in a triple therapy for H.pylori eradication in active duodenal ulcer

AIM:To assess and compare the efficacy and safety of two triple regimes:A)metronidazole,amoxicillin and omeprazole, which is still widely used in Russia,and B)azithromycin, amoxicillin and omeprazole in healing active duodenal ulcer and H.pylori eradication. METHODS:100 patients with active duodenal ulcer were included in the open,multicentre,randomized study with comparative groups.Patients were randomly assigned to one of the following one-week triple regimes:A) metronidazole 500 mg bid,amoxicillin I g bid and omeprazole 20 mg bid(OAM,n=50)and B)azithromycin 1 god for the first 3 days(total dose 3 g),amoxicillin 1 g bid and omeprazole 20 mg bid(OAA,n=50).Omeprazole 20 mg od was given after the eradication course as a monotherapy for three weeks.The control endoscopy was performed 8 weeks after the entry.H.pyloriinfection was determined in the entry of the study and four weeks after the cessation of treatment by means of histology and CLO-test. RESULTS:97 patients completed the study according to the protocol(1 patient of the OAM group did not come to the control endoscopy,2 patients of the OAA group stopped the treatment because of mild allergic urticaria).Duodenal ulcers were healed in 48 patients of the OAM group(96 %, C190.5-100 %)and in 46 patients of the OAA group(92 %, CI 89.5-94.5 %)(p=ns).H.pyloHinfection was eradicated in 15 out of 50 patients with OAM(30 %,CI 17-43 %)and in 36 out of 50 patients treated with OAA(72 %;CI 59-85 %) (P<0.001)-ITT analysis.CONCLUSION: The triple therapy with omeprazole, amoxicillin and metronidazole failed to eradicate H.pylori'vc\ the majority of patients, which is an essential argument to withdraw this regimen out of the national recommendations. Macrolide with amoxicillin are preferable to achieve higher eradication rates. Azithromycin (1 g od for the first 3 days) can be considered as a successful component of the triple PPI-based regimen.

Effects of the myeloperoxidase 463 gene polymorphisms on development of atrophy in H pylori infected or noninfected gastroduodenal disease

AIM： To investigate the relationship between myeloperoxidase polymorphisms as a host-related factor and atrophy caused by H pylori. METHODS： Our study enrolled 77 patients. Biopsy materials obtained during gastrointestinal endoscopies were evaluated for the presence of H pylori. Polymerase chain reaction-restriction fragment length polymorphism assay was used to characterize myeloperoxidase genothpes. RESULTS： Forty four patients （57.1%） were lip （＋） and 33 （42.9%） were Hp （-）. Sixty six （85.7%） had GG genotype, 10 （12.9%） had GA genotype and 1 （1.29%） had AA genotype. The change in atrophy in relation to neutrophil infiltration was significant in Hp （＋） patients （P = 0.0001）. The change in atrophy in relation to neutrophil infiltration in patients with GG genotype was significant （P = 0.002）. However, the change in atrophy in relation to neutrophil infiltration was not significiant in patients with Hp （＋） GG genotype （r = 0.066, P = 0.63）. CONCLUSION： Myeloperoxidase genotype is critical for development of atrophy in relation to the severity of inflammation. However, it is interesting to note that, H pylori does not show any additive effect on development of atrophy.

Gastrin and antral G cells in course of Helicobacter pylori eradication: Six months follow up study

AIM： To assess long-term effects of Helicobacter pylori （H pylon} eradication on antral G cell morphology and function in patients with and without duodenal ulcer （DU）.METHODS： Consecutive dyspeptic patients referred to the endoscopy entered the study. Out of 39 Hpylori positive patients, 8 had DU （Hpylori ＋DU） and 31 gastritis （Hpylori＋G）. Control groups consisted of 11 uninfected dyspeptic patients （CG1） and 7 healthy volunteers （CG2）. Basal plasma gastrin （PGL）, antral tissue gastrin concentrations （ATGC）, immunohistochemical and electron microscopic characteristics of G cells were determined, prior to and 6 mo after therapy.RESULTS： We-demonstrated elevated PGL in infected patients compared to uninfected controls prior to therapy.Elevated PGL were registered in all Hpylori＋patients （Hpylori＋DU： 106.78＋22.72 pg/mL, Hpylori＋G： 74.95＋15.63,CGI： 68.59＋17.97, CG2：39.24＋5.59 pg/mL, P〈0.01）.Successful eradication （e） therapy in Hpylori＋patients lead to significant decrease in PGL （Hpylori＋DU： 59.93＋9.40 and Hpylori＋Ge： 42.36＋10.28 pg/mL, P〈0.001）. ATGC at the beginning of the study were similar in infected and uninfected patients and eradication therapy lead to significant decrease in ATGC in Hpylori＋gastritis, but not in DU patients. In the Hpylori＋DU patients, the mean number of antral G cells was significantly lower in comparison with all other groups （P〈0.01）, but after successful eradication was close to normal values found in controls. By contrast, G cell number and volume density were significantly decreased （P〈0.01） in Hpylori＋Ge group after successful eradication therapy （294＋32 and 0.31＋0.02,respectively）, in comparison to values before eradication （416~40 and 0.48~0.09）. No significant change of the G cell/total endocrine cell ratio was observed during the 6 mo of follow up in any of the groups. A reversible increase in G cell secretory function was seen in all infected individuals, demonstrated by a more prominent secretory apparatus. However, differences between DU and gastritis group were identified.CONCLUSION： H py/oriinfection induces antral G cell hyperfunction resulting in increased gastrin synthesis and secretion. After eradication therapy complete morphological and functional recovery is observed in patients with gastritis. In the DU patients some other factors unrelated to the Hpyloriinfection influence antral G cell morphology and function.

Trends in the eradication rates of Helicobacter pylori infection for eleven years

AIM:To evaluate the trends in the eradication rate of Helicobacter pylori(H.pylori) over the past 11 years in a single center.METHODS:This retrospective study covered the period from January 2000 to December 2010.We evaluated 5746 patients diagnosed with gastric ulcers(GU),duodenal ulcers(DU),GU + DU,or nonpeptic ulcers associated with an H.pylori infection.We treated them annually with the 2 wk standard first-line triple regimen,proton pump inhibitor(PPI) + amoxicilin + clarithromycin(PAC;PPI,clarithromycin 500 mg,and amoxicillin 1 g,all twice a day).The follow-up test was performed at least 4 wk after the completion of the 2 wk standard H.pylori eradication using the PAC regimen.We also assessed the eradication rates of 1 wk second-line therapy with a quadruple standard regimen(PPI b.i.d.,tripotassium dicitrate bismuthate 300 mg q.i.d.,metronidazole 500 mg t.i.d.,and tetracycline 500 mg q.i.d.) after the failure of the first-line therapy.Statistical analysis was performed with 95%CI for the differences in the annual eradication rates.RESULTS:A total of 5746 patients [2333 males(58.8%),1636 females(41.2%);mean age of males vs females 51.31 ± 13.1 years vs 52.76 ± 13.6 years,P < 0.05,total mean age 51.9 ± 13.3 years(mean ± SD)] were investigated.Among these patients,1674 patients were excluded:35 patients refused treatment;18 patients ceased H.pylori eradication due to side effects;1211 patients had inappropriate indications for H.pylori eradication,having undergone stomach cancer operation or chemotherapy;and 410 patients did not undergo the follow-up.We also excluded 103 patients who wanted to stop eradication treatment after only 1 wk due to poor compliance or the side effects mentioned above.Finally,we evaluated the annual eradication success rates in a total of 3969 patients who received 2 wk first-line PAC therapy.The endoscopic and clinical findings in patients who received the 2 wk PAC were as follows:gastric ulcer in 855(21.5%);duodenal ulcer in 878(22.1%);gastric and duodenal ulcer in 124(3.1%),erosive,atrophic gastritis and functional dyspepsia in 2055(51.8%);and other findings(e.g.,MALToma,patients who wanted to receive the therapy even though they had no abnormal endoscopic finding) in 57(0.5%).The overall eradication rate of the 2 wk standard firstline triple regimen was 86.5%.The annual eradication rates from 2000 to 2010 were 86.7%,85.4%,86.5%,83.3%,89.9%,90.5%,88.4%,84.5%,89.1%,85.8%,and 88.3%,sequentially(P = 0.06).No definite evidence of a significant change in the eradication rate was seen during the past eleven years.The eradication rates of second-line therapy were 88.9%,82.4%,85%,83.9%,77.3%,85.7%,84.4%,87.3%,83.3%,88.9%,and 84%(P = 0.77).The overall eradication rate of 1 wk quadruple second-line therapy was 84.7%.There was no significant difference in the eradication rate according to the H.pylori associated diseases.CONCLUSION:This study showed that there was no trend change in the H.pylori eradication rate over the most recent 11 years in our institution.

Indistinguishable cellular changes in gastric mucosa between Helicobacter pylori infected asymptomatic tribal and duodenal ulcer patients

AIM： To investigate the changing pattern of different histological parameters occurring in the stomach tissue of Helicobacter pylori （H pylori） infected tribal populations and duodenal ulcer patients among ethnic Bengalis and correlation of the genotypes of H pylori with different histological parameters. METHODS： One hundred and twelve adult individuals were enrolled into this study between 2002 and 2004. Among them, 72 had clinical features of duodenal ulcer （DU） from ethnic Bengali population and 40 were asymptomatic ethnic tribals. Endoscopic gastric biopsy samples were processed for histology, genotyping and rapid urease test. Histologically, haematoxylin and eosin staining was applied to assess the pathomorphological changes and a modified Giemsa staining was used for better detection of Hpylori. For intestinal metaplasia, special stainings, i.e. Alcian blue periodic acid-Schiff and high iron diamine-Alcian blue staining, were performed. PCR was performed on bacterial DNA to characterize the presence or absence of virulence-associated genes, like cagA, and distribution of different alleles of vacA and iceA. RESULTS： Intraglandular neutrophil infiltration, a hallmark of activity of gastritis, was present in 34 （94%） of tribals （TRs） and 42 （84%） of DU individuals infected with H pylori. Lymphoid follicles and aggregates, which are important landmarks in H pylori infection, were positive amongst 15 （41%） of TRs and 20 （40%） of DU subjects. Atrophic changes were observed in 60% and 27.7%, respectively, among DU cases and tribals （P 〉 0.003）. Metaplastic changes were detected in low numbers in both groups. Moderate to severe density distribution of Hpylori in the gastric mucosa was 63% among TRs, whereas it was 62% in DU subjects. There were no significant differences in the distribution of virulence-associated genes like cagA, vacA and iceA of H pylori strains carried by these two populations. CONCLUSION： Our study showed almost similar distribution of inflammatory cells among asymptomatic tribals and DU Bengali patients. Interestingly, the tribal population are free from any clinical symptoms despite evidence of active histologic gastritis and infection with Hpylori strains carrying similar virulence markers as of strains isolated from patients with DU. There was an increased cellular response, especially in terms of neutrophil infiltration, but much lower risk of developing atrophy and metaplastic changes among the tribal population.

Response of blood endothelin-1 and nitric oxide activity in duodenal ulcer patients undergoing Helicobacter pylori eradication

AIM: To investigate the effect of Helicobacter pylori eradication on endothelin-1 (ET-1) and nitric oxide (NO) in duodenal ulcer (DU) patients. METHODS: Sixty-six Hpylori-infected active DU patients were consecutively enrolled to receive one-week triple therapy (rabeprazole, amoxicillin and metronidazole) and then one-month rabeprazole therapy. They were asked back to determine ulcer and Hpylori status using endoscopy one month later. Thirty-seven healthy controls (H pylori +/-:17/20) were enrolled for comparison. Blood samples were collected in each visit to measure plasma ET-1 and nitrate/nitrite levels using an enzyme immunoassay kit. RESULTS: Sixty DU patients finished trial per protocol. The ulcer healing and Hpylori-eradication rates were 86.7% and 83.3%, respectively. Plasma ET-1 level in DU patients was higher than that of Hpylori-negative and positive controls (3.59±0.96 vs0.89±0.54 vs0.3±0.2 pg/mL,P<0.01), while nitrate/nitrite levels among them were also significantly different (8.55±0.71 vs5.27±0.68 vs 6.39±0.92 μmol/L, P<0.05). H pylori eradication diminished ET-1 levels (3.64±0.55 vs2.64±0.55 pg/mL, P<0.01) but elevated nitrate/ nitrite level (8.16±0.84 vs11.41±1.42 umol/L,P<0.05). CONCLUSION: Both plasma ET-1 and nitrate/nitrite levels increase in active DU patients. After an effective H pylori eradication, DU healing is associated with diminished blood ET-1 level and elevated nitrate/nitrite level.

The vacA i1 genotype of Helicobacter pylori is associated with peptic ulcer and gastric cancer:A meta-analysis

There are two genotypes of the vacA intermediate region, il and i2; however, the association between the genotypes and gastroduodenal disease remains to be elucidated. The aim of this article was to investigate the interaction between the genotypes and H. py/ori-associated diseases such as chronic gastritis, peptic ulcer disease （PUD） and gastric cancer. Methods： The meta-analysis was performed in Review Manager 4.2.2. Results： Eleven （ten articles and one abstract） met the inclusion criteria and were included. The il genotype increased the risk of PUD （OR = 1.70, 95% CI： 1.24-2.33, P 〈 0.001） and gastric cancer （OR = 3.90, 95% CI： 2.64-5.78, P 〈 0.001）. Sub-analysis showed that the il genotype was significantly associated with gastric ulcers （OR = 2.59, 95% CI： 1.05-6.35, P = 0.040）, but not with duodenal ulcers （OR = 1.04, 95% CI： 0.61-1.76, P = 0.90）. In addition, the association between the il genotype and PUD and GC existed in studies not only from Europe but also Asia, except for the association between the il genotype and PUD in Asian population. Conclusion： The vacA il genotype is associated with an increased risk of the development of peptic ulcer disease （mainly gastric ulcer） and gastric cancer. In geographical distribution, the association between the il genotype and PUD and GC existed in studies not only from Europe but also Asia, except for the association between the il genotype and PUD in Asian population.

Purification and Characterization of a Nonylphenol （NP）-degrading Enzyme from Bacillus cereus.Frankland

An extracellular NP-degrading enzyme secreted by Bacillus cereus.Frankland was purified to homogeneity by a combination of ammonium sulfate precipitation,Phenyl-Sepharose hydrophobic-interaction chromatography and DEAE anion-exchange chromatography.On SDS（sodium dodecyl sulfate）-polyacrylamide gel electrophoresis analysis,the purified enzyme showed a relative molecular mass of 58.3 kDa.The depolymerzation of subunits was accompanied with the loss of NP-degrading enzyme activity,and removing denaturing factors by dialysis could restore the dimer structure and enzymatic activity.The enzyme had an isoelectric point of 5.5 and an optimal temperature of 60℃,and was the most active at pH 6.0.The enzymatic activity was stable at pH 4-8 and inhibited by Cu2＋.TenN-terminal amino acids were determined to be ASVNSIKIGY,demonstrating that the purified enzyme was a novel one.The hydrolysis pattern of the purified enzyme indicated that the NP-degrading enzyme was an endo NP-degrading enzyme.The extraordinary thermo-stability provided the enzyme with a good prospect to be used as a new tool for clean-production process for textile industry.