Helicobacter pylori infection

Prevalence and Possible Predictors of Helicobacter Pylori Infection Among Adult Patients with Sickle Cell Disease in Ahmadu Bello University Teaching Hospital North-West, Nigeria

Background

Helicobacter Pylori (H. pylori) infection occurs worldwide. Patients with Sickle Cell Disease (SCD) may present with abdominal symptoms due to different pathophysiological mechanisms. SCD patients are predisposed to infections due to immune deficiency, abdominal symptoms like dyspepsia and recurrent abdominal pain have been associated with H. pylori infection. This study determined H. pylori prevalence in adult SCA patients and its relationship with socio-demographic, clinical, and laboratory parameters.

Methodology

Adult patients with SCA in Steady State were enrolled after informed consent. Sociodemographic, clinical, and laboratory parameters were documented using a structured questionnaire. H. pylori IgG antibody was detected using lateral flow Rapid Diagnostic Test (FaStep USA). Data were analyzed using EpiInfo 7.2.

Results

The median age of participants was 23(20, 26) years. Most of the participants (56.8%) were from lower socioeconomic classes. Sickle cell painful vaso-occlusive crises and blood transfusion in the previous 12 months were 2(1, 4) and 0(0, 1) respectively. Ninety (53.3%) of the participants had abdominal symptoms. Non-specific abdominal pain was the most common. The median frequency of abdominal pains was 1(0, 2). H pylori infection was found in 23.1%. The Odds for H. Pylori infection was high in participants with abdominal symptoms, antacid use, and multiple abdominal symptoms {OR=1.552, 1.306, and 2.584 respectively) though not statistically significant. At the same time those with recurrent abdominal pain and male sex had lower Odds (OR=0.875 and 0.831respectively), though not statistically significant.

Conclusion

H. pylori infection is not uncommon among SCA patients. Physicians should be vigilant in SCD patients with multiple abdominal symptoms by screening early and instituting management.

Relationship between Helicobacter pylori infection and white matter lesions in patients with migraine

Background/aim

White matter lesions (WML) are more frequently observed in migraine patients than in the average population. Associations between Helicobacter pylori (H. pylori) infection and different extraintestinal pathologies have been identified. Here, we aimed to investigate the association between H. pylori infection and WML in patients diagnosed with episodic migraine.

Materials and methods

A retrospective study was conducted with 526 subjects with a diagnosis of episodic migraine. Hyperintensity of WML had been previously evaluated in these patients with brain magnetic resonance imaging (MRI) examinations. Previous endoscopic gastric biopsy histopathological examination of the same patients and reports on H. pylori findings were recorded. The demographic characteristics of the patients, such as age, gender and chronic systemic diseases such as hypertension and diabetes mellitus (DM) were recorded. Statistical evaluation was made.

Results

Evaluation was made among 526 migraine patients who met the inclusion criteria, comprising 397 (75.5%) females and 129 (24.5%) males with a mean age of 45.57 ± 13.46 years (range, 18–69 years). WML was detected on brain MRI in 178 (33.8%) patients who were also positive for H. pylori (p <  0.05). Subjects who are H. pylori-positive with migraine, WML were observed at a 2.5-fold higher incidence on brain MRI (odds ratio: 2.562, 95% CI 1.784–3.680). WML was found to be more significant in patients with hypertension and migraine than those without (p <  0.001). Older age was also found to be associated with WML (OR = 1.07, 95% CI: 0.01–0.04, p <  0.001). The age (p <  0.001), H. pylori (p <  0.001), hypertension (p <  0.001), and hypertension + DM (p <  0.05), had significant associations in predicting WML according to the multivariate logistic regression analysis. The presence of hypertension had a higher odds ratio value than the other variables.

Conclusion

It was concluded that H. pylori infection, as a chronic infection, can be considered a risk factor in developing WML in subjects with migraine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02715-0.

Helicobacter pylori infection and micronutrient deficiency in pregnant women: a systematic review and meta-analysis

Background

Over the last few years, epidemiological studies have shown that infection with Helicobacter pylori has a major effect on micronutrient deficiency as well as on adverse pregnancy outcomes. Importantly, there are gaps in understanding the linkage of H. pylori infection with micronutrients deficiency in pregnant women.

Objective

We conducted a systematic review and meta-analysis to estimate the association between H. pylori infection and micronutrient deficiencies in pregnant women.

Methods

A systematic literature search was conducted for relevant articles using PubMed, Web of Science, and Scopus database from inception to March 2020. The OR with 95% CIs was determined by meta-analysis of data extracted from the selected studies.

Results

From 2384 primary articles, 6 studies were selected for systematic reviews and 4 studies distinctively (with 1274 participants: 553 cases and 721 controls) were selected for meta-analysis. The meta-analysed fixed effect model estimated the odds of having H. pylori infection was not significantly higher among pregnant women with micronutrient deficiencies than those without deficiencies (OR=1.12, 95% CI 0.88 to 1.42, p=0.37). In the subgroup analysis, no correlation was found between H. pylori infection and vitamin B₁₂ (OR=0.74, 95% CI 0.45 to 1.21, p=0.22), folate (OR=1.07, 95% CI 0.73 to 1.58, p=0.73), and ferritin (OR=0.81, 95% CI 0.51 to 1.31, p=0.4). However, a positive correlation was found between iron-deficiency anaemia (IDA) and H. pylori infection (OR=16.23, 95% CI 4.19 to 62.93, p<0.0001) during pregnancy.

Conclusion

H. pylori infection is associated with increased risk of IDA but not with deficiency of other micronutrients in pregnancy.

PROSPERO registration number

CRD42019135683.

Spectroscopic characterization and fluorescence imaging of Helicobacter pylori endogenous porphyrins

Conventional antimicrobial strategies have become increasingly ineffective due to the rapid emergence of antibiotic resistance among pathogenic bacteria. In order to overcome this problem, antimicrobial PhotoDynamic Therapy (PDT) is considered a promising alternative therapy. PDT has a broad spectrum of action and low mutagenic potential. It is particularly effective when microorganisms present endogenous photosensitizing pigments. Helicobacter pylori (Hp), a pathogen notoriously responsible of severe gastric infections (chronic gastritis, peptic ulcer, MALT lymphoma and gastric adenocarcinoma), produces and accumulates the photosensitizers protoporphyrin IX and coproporphyrin, thus it might be a suitable target of antimicrobial PDT. With the aim to design and develop an ingestible LED-based robotic pill for intragastric phototherapy, so that irradiation can be performed in situ without the use of invasive endoscopic light, photophysical studies on the Hp endogenous photosensitizers were carried out. These studies represent an important prerequisite in order to select the most effective irradiation conditions for Hp eradication. The photophysical characterization of Hp porphyrins, including their spectroscopic features in terms of absorption, steady-state and time-resolved fluorescence, was performed on bacterial extracts as well as within planktonic and biofilm growing Hp cells.

Hadi AH, Mohd Ali H, Majid N, Abdulla MA. Acute toxicity and gastroprotection studies of a new schiff base derived copper (II) complex against ethanol-induced acute gastric lesions in rats

BACKGROUND

Copper is an essential element in various metabolisms. The investigation was carried out to evaluate acute gastroprotective effects of the Copper (II) complex against ethanol-induced superficial hemorrhagic mucosal lesions in rats.

METHODOLOGY/PRINCIPAL FINDINGS

Rats were divided into 7 groups. Groups 1 and 2 were orally administered with Tween 20 (10% v/v). Group 3 was orally administered with 20 mg/kg omeprazole (10% Tween 20). Groups 4-7 received 10, 20, 40, and 80 mg/kg of the complex (10% Tween 20), respectively. Tween 20 (10% v/v) was given orally to group 1 and absolute ethanol was given orally to groups 2-7, respectively. Rats were sacrificed after 1 h. Group 2 exhibited severe superficial hemorrhagic mucosal lesions. Gastric wall mucus was significantly preserved by the pre-treatment complex. The results showed a significant increase in glutathione (GSH), superoxide dismutase (SOD), nitric oxide (NO), and Prostaglandin E2 (PGE(2)) activities and a decrease in malondialdehyde (MDA) level. Histology showed marked reduction of hemorrhagic mucosal lesions in groups 4-7. Immunohistochemical staining showed up-regulation of Hsp70 and down-regulation of Bax proteins. PAS staining of groups 4-7 showed intense stain uptake of gastric mucosa. The acute toxicity revealed the non-toxic nature of the compound.

CONCLUSIONS/SIGNIFICANCE

The gastroprotective effect of the Copper (II) complex may possibly be due to preservation of gastric wall mucus; increase in PGE(2) synthesis; GSH, SOD, and NO up-regulation of Hsp70 protein; decrease in MDA level; and down-regulation of Bax protein.

Aspirin increases susceptibility of Helicobacter pylori to metronidazole by augmenting endocellular concentrations of antimicrobials

AIM: To investigate the mechanisms of aspirin increasing the susceptibility of Helicobacter pylori (H pylori) to metronidazole.

METHODS: H pylori reference strain 26 695 and two metronidazole-resistant isolates of H pylori were included in this study. Strains were incubated in Brucella broth with or without aspirin (1 mmol/L). The rdxA gene of H pylori was amplified by PCR and sequenced. The permeability of H pylori to antimicrobials was determined by analyzing the endocellular radioactivity of the cells after incubated with [7-³H]-tetracycline. The outer membrane proteins (OMPs) of H pylori 26 695 were depurated and analyzed by SDS-PAGE. The expression of 5 porins (hopA, hopB, hopC, hopD and hopE) and the putative RND efflux system (hefABC) of H pylori were analyzed using real-time quantitative PCR.

RESULTS: The mutations in rdxA gene did not change in metronidazole resistant isolates treated with aspirin. The radioactivity of H pylori increased when treated with aspirin, indicating that aspirin improved the permeability of the outer membrane of H pylori. However, the expression of two OMP bands between 55 kDa and 72 kDa altered in the presence of aspirin. The expression of the mRNA of hopA, hopB, hopC, hopD, hopE and hefA, hefB, hefC of H pylori did not change when treated with aspirin.

CONCLUSION: Although aspirin increases the susceptibility of H pylori to metronidazole, it has no effect on the mutations of rdxA gene of H pylori. Aspirin increases endocellular concentrations of antimicrobials probably by altering the OMP expression.

Expression of Helicobacter pylori cagA and vacA and their correlations with Helicobacter pylori infection in gastric cancer

AIM: To explore the expression of H. pylori cagA and vacA in gastric cancer and their correlations with H. pylori infection.

METHODS: H. pylori infection was determined by Warthin-Starry silver staining in gastric cancer (n = 39), gastric mucosal atypical hyperplasia (n = 24) and chronic gastritis (n = 33). Polymerase chain reaction (PCR) was used to detect the expression of H. pylori cagA and vacA.

RESULTS: The infection rates of H. pylori, cagA⁺H. pylori and vacA⁺H. pylori in gastric cancer tissues were significantly higher than those chronic gastritis tissue (χ² = 7.00, P < 0.05; χ² = 15.20, P < 0.05; χ² = 12.43, P < 0.05); the infection rates of H. pylori, cagA⁺H. pylori and vacA⁺H. pylori in gastric mucosal atypical hyperplasia were markedly higher than those in chronic gastritis (χ² = 6.25, P < 0.05; χ² = 11.04, P < 0.05; χ² = 11.61, P < 0.05). The infection rates of H. pylori, cagA⁺H. pylori and vacA⁺H. pylori were significantly higher in poorly-differentiated gastric cancer in comparison with those in moderately- and well-differentiated one (χ² = 8.19, P < 0.05; χ² = 13.14, P < 0.05; χ² = 6.62, P < 0.05). H. pylori infection was positively related to H. pylori cagA and vacA expression in chronic gastritis, gastric mucosal atypical hyperplasia and gastric cancer (chronic gastritis: r = 0.56, P < 0.01; r = 0.64, P < 0.01; atypical hyperplasia: r = 0.64, P < 0.01; r = 0.92, P < 0.01; gastric cancer: r = 0.90, P < 0.01; r = 0.95, P < 0.01).

CONCLUSION: H. pylori infection is an important promoter in the development of chronic gastritis into atypical hyperplasia and gastric cancer, and it may accelerate the proliferation and injury of gastric mucosa epithelial cells by inducing cagA and vacA expression, respectively. Their synergistic effects may play important roles in the pathogenesis of gastric cancer.

Helicobacter infection in hepatocellular carcinoma tissue

AIM: To investigate whether Helicobacter species (Helicobacter spp.) could be detected in hepatocellular carcinoma (HCC) tissue.

METHODS: Liver samples from 28 patients with hepatocellular carcinoma (HCC) diagnosed by histopa-thology were studied. Twenty-two patients with other liver diseases (5 with liver trauma, 7 with cavernous liver hemangioma, 6 with liver cyst and 4 with hepatolithiasis), 25 patients with gastric cancer, 15 with colonic cancer and 15 with myoma of uterus served as controls. Two pieces of biopsy were obtained from each patient. One was cultured for Helicobacter spp. and extraction of DNA, the other was prepared for scanning electron microscopy (SEM) and in situ hybridization. The samples were cultured on Columbia agar plates with microaerobic techniques. Helicobacter spp. in biopsy from the studied subjects was detected by polymerase chain reaction (PCR) with Helicobacter spp. 16S rRNA primers. Amplified products were identified by Southern hybridization and sequenced further. Besides, other genes (vacA, cagA) specific for Helicobacter pylori (H pylori) were also detected by PCR. Helicobacter spp. in biopsies was observed by SEM. Transmission electron microscopy (TEM) was performed to identify the cultured positive Helicobacter spp. The presence of Helicobacter spp. was detected by in situ hybridization to confirm the type of Helicobacter.

RESULTS: The positive rate of Helicobacter cultured in HCC and gastric cancer tissue was 10.7% (3/28) and 24%(6/25), respectively. Helicobacter microorganisms were identified further by typical appearance on Gram staining, positive urease test and characteristic colony morphology on TEM. The bacterium was observed in adjacent hepatocytes of the two HCC samples by SEM. The number of cocci was greater than that of bacilli. The bacterium was also found in four gastric cancer samples. PCR showed that the positive rate of HCC and gastric cancer samples was 60.7% and 72% respectively, while the controls were negative (P < 0.01). The PCR-amplified products were identified by Southern hybridization and sequenced. The homology to 16S rRNA of H pylori was 97.80%. The samples were verified by in situ hybridization for Helicobacter spp. 16S rRNA-mRNA and proved to be H pylori positive. There was no statistical significance between HCC and gastric cancer (P > 0.05), but the positive rate of HCC and controls had statistical significance (P < 0.01). Only 3 HCC samples and 2 gastric cancer samples of the cagA genes were detected. None of the samples reacted with primers for vacA in the two groups. As for the genotype of H pylori, type II had preference over type I.

CONCLUSION: Helicobacter infection exists in liver tissues of HCC patients. Helicobacter spp. infection is related with HCC, which needs further research.

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Effect of Helicobacter pylori infection on Bax protein expression in patients with gastric precancerous lesions

AIM: To investigate the effect of Helicobacter pylori (H pylori) infection on Bax protein expression, and explore the role of H pylori in gastric carcinogenesis.

METHODS: H pylori was assessed by rapid urease test and Warthin-Starry method, and expression of Bax protein was examined immunohistochemically in 72 patients with pre-malignant lesions.

RESULTS: Bax protein was differently expressed in intestinal metaplasia and gastric dysplasia, and showed 63.99% positivity. The positivity of Bax protein expression in H pylori-positive gastric precancerous lesions (72.3%) was significantly higher than that in H pylori-negative gastric precancerous lesions (48.0%, c2 = 4.191, P < 0.05). H pylori infection was well correlated with the expression of Bax protein in gastric precancerous lesions (r = 0.978, P < 0.01). After eradication of H pylori, the positivity of Bax protein expression significantly decreased in H pylori-positive gastric precancerous lesions (c2 = 5.506, P < 0.05). In the persisting H pylori-infected patients, the positivity of Bax protein expression was not changed.

CONCLUSION: H pylori infection may be involved in the upregulation of Bax gene, which might be one of the mechanisms of H pylori infection-induced gastric epithelial cell apoptosis. H pylori might act as a tumor promoter in the genesis of gastric carcinoma and eradication of H pylori could inhibit gastric carcinogenesis.

Systemic immune responses to oral administration of recombinant attenuated Salmonella typhimurium expressing Helicobacter pylori urease in mice

AIM

To evaluate whether attenuated Salmonella typhimurium producing Helicobacter pylori (H pylori) urease subunit B (UreB) could induce systemic immune responses against H pylori infection.

METHODS

Attenuated S. typhimurium SL3261 was used as a live carrier of plasmid pTC01-UreB, which encodes recombinant H pylori UreB protein. Balb/c mice were given oral immunization with two doses of SL3261/pTC01-UreB at a 3-wk interval. Twelve weeks after oral immunization of mice, serum IgG antibodies were evaluated by ELISA assay. Gamma interferon (IFN-gamma) and interleukin 10 (IL-10) in the supernatant of spleen cell culture were also assessed by ELISA.

RESULTS

After oral immunization of mice, serum specific IgG antibodies against UreB in vaccine group were much higher than that in PBS and native Salmonella SL3261 control groups (A450, 0.373+/-0.100 vs 0.053+/-0.022, 0.142+/-0.039, respectively, P<0.01). Moreover, IFN-gamma in vaccine group was on average 167.53+/-29.93 pg/mL, which showed a significant increase vs that of PBS control group (35.68+/-3.55 pg/mL, P<0.01). There was also a tremendous increase of IL-10 in vaccine group compared to PBS and SL3261 control groups (275.13+/-27.65 pg/mL vs 56.00+/-7.15 pg/mL, 68.02+/-15.03 pg/mL, respectively, P<0.01). In addition, no obvious side effects in mice and no change in gastric inflammation were observed.

CONCLUSION

The multiple oral immunizations with the attenuated S. typhimurium expressing H pylori UreB could induce significant systemic immune responses, suggesting it may be used as oral vaccine against H pylori infection.

Detection of Helicobacter pylori cagA gene in patients with digestive diseases in Guangxi and its clinical significance

AIM: To study the positive rate of Helicobacter pylori (H. pylori) cagA gene of strains and the virulence of H. pylori infecting patients in Guangxi, China.

METHODS: H. pylori strains were isolated in gastric biopsy specimens from the patients with chronic gastritis and peptic ulcer in Nanning area of Guangxi. The sequence of D008/R008 primers were used to amplify 297 bp fragment of cagA gene and PCR were used to detect the frequency of cagA gene in the 45 H. pylori isolates.

RESULTS: The positive rate of cagA gene in H. pylori strains was 84.4% (38/45). The positive rate of cagA gene in peptic ulcer (PU) patients was 76.0% (19/25), which was lower than that in chronic gastritis (CG) patients (95.0%,19/20), but there was no significant difference (P > 0.05). The positive rate of cagA gene was higher in female patients than that in male patients (100.0% vs 73.1%, P < 0.01). The positive rate of cagA gene in different age groups was no significant difference (P > 0.05).

CONCLUSION: The positive rate of cagA gene in H. pylori strains among patients in Guangxi is high, and the positive rate is lower in PU patients than that in CG patients, and higher in male than female patients. But there is no significant difference in different age groups.

Serum pepsinogen concentration as an index for Helicobacter pylori eradication

AIM: To investigate the utilization of serum pepsinogen (PG) as an index for Helicobacter eradication.

METHODS: Serum PGI and PGⅡ concentrations were detected with immunoradiometric assay (IRMA) in 359 patients with H. pylori infection, who were treated for eradication by routine triple therapy, before and 1, 5 and 18 mos after treatment. Three methods were used to determine the result of eradication: HE staining, Hp-DNA PCR and ELISA analysis.

RESULTS: Compared to serum level before treatment, serum PGI and PGⅡ concentrations decreased significantly in the eradication group (64.52±31.74 vs 48.02±25.69 μg/L, P < 0.01; 11.22±6.12 vs 7.58±5.41 μg/L, P < 0.01), and PGI/II ratio also increased significantly (6.54±3.57 vs 7.96±4.39, P < 0.01). Serum PGI and PGⅡ levels decreased after eradication in different disease groups. 1 and 5 mos after treatment, serum PGI and PGⅡconcentrations in the eradication group were significantly lower than those before treatment (PGI: 66.83±28.04 vs 52.54±27.96 μg/L, P < 0.01; 11.85±4.91 vs 6.55±3.59 μg/L, P < 0.01; PGII: 60.19±29.30 vs 43.94±26.27 μg/L; 10.93±6.12 vs 6.66±5.30 μg/L, P < 0.01), and PGI/Ⅱratio were significantly higher than the latter (5.84±2.38 vs 8.95±4.61, P < 0.01; 6.60±4.21 vs 8.35±4.82, P < 0.01); The marked drop was found with PGI/Ⅱratio 18 mos after treatment (68.12±36.05 vs 50.11±23.50 μg/L, P < 0.01). There were no remarkable changes with serum PG concentrations in uneradication group.

CONCLUSION: Serum pepsinogen levels are suitable for determining the effect of H. pylori eradication. PGI/Ⅱ ratio can be used as a good marker for determination in the early eradication.

Survival advantage in hosts with H. pylori infection

AIM: To study the in vitro killing effects of cecropin-like antibacterial peptide from H. pylori Hp (2-20) on the gastrointestinal bacterial pathogens and to explore the survival advantage to the host of infection with H. pylori.

METHODS: The inhibition zone assay was used to determine anti-bacterial activity and lethal concentrations of H. pylori antibacterial peptide Hp (2-20) on the gastrointestinal bacterial pathogens. The rate of killing of E.coli K₁₂D₃₁ (standard strain) by Hp (2-20) was estimated by counting viable bacteria based on counting of colonies grown in Luria-Bertani plate. The cytotoxicity of the Hp (2-20) peptides on human gastric epithelial cell line was measured by trypan blue exclusion test.

RESULTS: In vitro studies, the Hp (2-20) destroyed the gastrointestinal bacterial pathogens such as Shigella flexneri, Salmonella typhi, Salmonella paratyphi and enteropathogenic E.coli. The lethal concentrations (LC) were 65-197 mmoL/L. The viable bacterial count dropped to zero after 12 min incubation with Hp (2-20) concentration closed to the LC value. The Hp (2-20) was inactive against the strains of Yersinia enterocolitica and Staphylococcus aureus and had much higher LC (over 1014mmol/L). The killing effects of Cecropin B were more pronounced than Helicobacter peptide Hp (2-20). The synthetic peptideHp(2-20) showed no lytic or toxic activity against the human gastric epithelial cell line GES-1.

CONCLUSION: The cecropin-like antibacterial peptide from H. pylori Hp (2-20) is active against faster-growing gastrointestinal bacterial pathogens. There is no effect on the human gastric epithelial cells. H. pylori may actually have beneficial effects on infected carriers who are heavily exposed to other gastrointestinal pathogens.

Sequence diversity analysis of CagA gene and corresponding protein in Helicobacter pylori

AIM: To find the structural characteristics and correlation with region and the clinical outcomes by analyzing nucleotide and amino acid sequences of CagA, our research results and data of CagA sequences deposited in NCBI database.

METHODS: The characteristics of CagA sequences were analyzed, and a phylogenetic tree was constructed by using Vector NTI Suite 9.0, ClastalX (version 1.8), Phylip (version 3.5) and Treeview (version 1.61).

RESULTS: Through searching NCBI nucleotide and protein database, we obtained 44 complete and 560 partial CagA sequences. Aligning these sequences, analyzing similarity and constructing phylogenetic tree, we found CagA seqenceses could be classified into two types: western type and eastern type. Analyzing the CagA C terminal of 44 complete and 266 partial sequences, we classified the repeat sequence of CagA C terminal into two types: type I was discontinuous repeat sequence, common among all the strains, and type II was continuous repeat sequence, found in some individual strains. The type II repeat sequence was found in 31% (12/39) of strains from gastric cancer patients, compared with 13% (9/71) of strains from non-cancer patients (P = 0.021 < 0.05). Strains with the type II repeat sequence were associated with gastric cancer.

CONCLUSION: There is a high diversity of CagA nucleotide and amino acid sequences among H. pylori strains, showing a distinct geographic character as western and eastern region collection. The repeat sequence of CagA C terminal can be classified into two types, and strains with the type II repeat sequence containing EPIYA motif exhibits a stronger pathogenecity.

Prokaryotic expression of fusion gene of vacuolating segment of vacA and hpaA in Helicobacter pylori

AIM: The prokaryotic expression vector of the fusion gene with v segment of the vacuolating cytotoxin and hpaA of Helicobacter pylori (H. pylori) was constructed and expressed. It would lay a foundation for prophylaxis and therapy of H. pylori infection.

METHODS: By using the primer with a fragment encoding 12 amino acids of N-terminal of human interleukin-3 (IL-3), the vacuolating cytotoxin gene of Hp with linker was amplified from pQE30-V plasmid by PCR. The gene was cloned into plasmid pTrc99A-HpaA and fused with the hpaA gene. The fusion gene was cloned into prokaryotic expression vector pQE30. The recombinant plasmid of pQE30-V-HpaA was transformed into E.coli. DH5a and expressed in the presence of IPTG. The expression product was analyzed by SDS-PAGE, its antigenicity of the expression product was identified by Western blotting.

RESULTS: Mr of recombinant protein was about 65 000 and represented 35% total protein of E.coli. Western blotting showed the recombinant protein could be recognized by the antiserum against H. pylori.

CONCLUSION: The fusion gene and its prokaryotic expression vector pQE30-V-HpaA is constructed and expressed in DH5asuccessfully. It provides the antigen basis for further studying the biological function of fusion protein and obtaining vaccine against the infection of H. pylori.

Association between Helicobacter pylori infection and expression of COX-2 and iNOS in chronic gastritis

AIM: To investigate the expression of COX-2 and iNOS in H. pylori associated chronic gastritis, and also to analyze the relationship between apoptosis and proliferation and COX-2, iNOS expression in gastric epithelia cells.

METHODS: A total of 22 patients were diagnosed as having chronic superficial gastritis by endoscopy and pathology. H. pylori infection was detected by fast urease and Giemsa stain. The expression of COX-1, COX-2, and iNOS was detected by RT-PCR and immunohistochemistry. Apoptosis and proliferation of gastric epithelial cells were quantitated by apoptosis index (AI) and PCNA labelling index (PCNA-LI).

RESULTS: There was a significant increase in both COX-2 and iNOS expression in H. pylori positive gastritis compared with normal mucosa. Epithelial cell proliferation index and apoptosis index in H. pylori gastritis were greater than that in normal mucosa; Expression of COX-2 and iNOS induced by H. pylori had positive correlation with apoptosis and proliferation in gastric epithelial cells (r = 0.716,0.603, P < 0.01; r = 0.665, 0.572, P < 0.01).

CONCLUSION: H. pylori infection leads to gastric mucosal overexpression of COX-2 and iNOS, which is involved in apoptosis and proliferation inbalance in gastric epithelial cells. Therefore, it may be one of the crucial mechanisms of H. pylori inducing gastric cancer.

Trends in peptic ulcer pharmacotherapy

Considering the diseases of the stomach and duodenum, peptic ulcer has been the one with a significant clinical impact. The pathophysiology of peptic ulcer has centred on an imbalance between aggressive and protective factors. The discovery of Helicobacter pylori as a cause of peptic ulcer has changed our approach greatly towards this disease. Despite the decreasing frequency of H. pylori-induced peptic ulcers, peptic ulcer remains a major clinical problem partly because nonsteroidal anti-inflammatory drug (NSAID)-related ulcers and hospital admissions for ulcer complications associated with NSAIDs have increased in frequency. The interaction between H. pylori and NSAIDs is one of the most controversial issues in peptic ulcer. In this article, current concepts of peptic ulcer etiopathogenesis and the management of peptic ulcer according to the etiology were reviewed.

Influence of H. pylori on cyclinD1 and PCNA mRNA expression in HepG2 cell line

AIM: To observe the effects of Helicobacter pylori (H. pylori) on cyclinD1 and PCNA mRNA expression in a human hepatoma cell line HepG2.

METHODS: H. pylori was co-cultured with HepG2 for 1, 3,6, 12 and 24 h. The cyclinD1 and PCNA mRNA expression was detected by semi-quantitative RT-PCR.

RESULTS: When HepG2 cells were cocultured with H. pylori CagA⁺ strain, the amount of cyclinD1 mRNA was increased 4.0-fold by 3 h and PCNA mRNA was increased 2.0-fold by 6 h, compared with that of uninfected control. Neither cyclinD1 mRNA nor PCNA mRNA of the HepG2 cells was increased after incubation with H. pylori CagA^- strain.

CONCLUSION: H. pylori can induce increasing expression of cyclinD1 and PCNA mRNA in HepG2, which may play some roles in the development of hepatocellular carcinoma.

Expression of Helicobacter pylori Hsp60 protein and its immunogenicity

AIM: To express Hsp60 protein of H pylori by a constructed vector and to evaluate its immunogenicity.

METHODS: Hsp60 DNA was amplified by PCR and inserted into the prokaryotie expression vector pET-22b (+), which was transformed into BL21 (DE3) E.coli strain to express recombinant protein. Immunogenicity of expressed Hsp60 protein was evaluated with animal experiments.

RESULTS: DNA sequence analysis showed Hsp60 DNA was the same as GenBank’s research. Hsp60 recombinant protein accounted for 27.2% of the total bacterial protein, and could be recognized by the serum from H pylori infected patients and Balb/c mice immunized with Hsp60 itself.

CONCLUSION: Hsp60 recombinant protein might become a potential vaccine for controlling and treating H pylori infection.

Detection of serum anti-Helicobacter pylori immunoglobulin G in patients with different digestive malignant tumors

AIM: To investigate the seroprevalence of Helicobacter pylori infection in patients with different digestive malignant tumors.

METHODS: Enzyme linked immunosorbent assay (ELISA) was used to detect serum anti-Helicobacter pylori IgG antibody in 374 patients with different digestive malignant tumors and 310 healthy subjects (normal control group).

RESULTS: The seroprevalence of Helicobacter pylori infection was 61.50% (230/374) and 46.77% (145/310), respectively, in patients with digestive tumors and normal controls (P < 0.05). The seroprevalence was 52.38% (33/63), 86.60% (84/97), 83.14% (84/101), 45.24 (19/42), 51.13% (18/35) and 44.44% (16/36), respectively in patients with carcinomas of esophagus, stomach, duodenum, rectum, colon and liver (P < 0.01). In patients with intestinal and diffuse type gastric cancers, the seroprevalence was 93.75% (60/64) and 72.73% (24/33), respectively (P < 0.05). In patients with gastric antral and cardiac cancers, the seroprevalence was 96.43% (54/56) and 73.17% (30/41), respectively (P < 0.05). In patients with ulcerous and proliferous type duodenal cancers, the seroprevalence of H. pylori infection was 91.04% (61/67) and 52.27% (23/44), respectively (P < 0.05). In patients with duodenal bulb and descending cancers, the seroprevalence was 94.20% (65/69) and 45.20% (19/42), respectively (P < 0.05).

CONCLUSION: H. pylori infection is associated with occurrence and development of gastric and duodenal carcinomas. Furthermore, it is also associated with histological type and locations of gastric and duodenal carcinomas.

Molecular mechanism of the resistance of Helicobacter pylori to clarithromycin

AIM

To investigate the resistance mechanism of Hp to clarithromycin.

METHODS

With E-test method, we examined the minimal inhibitory concentration (MIC) to clarithromycin of 35 Hp clinical isolates. Resistance strains were defined when MIC≥8 mg/L. Extract the DNA from the bacteria with the phenol-chloroform extraction method. Then amplify the fragments from 2 047 to 2 347 of 23 S rRNA gene. Gene sequence of the PCR products was analyzed to observe the mutation in the resistant Hp strains.

RESULTS

Compared with susceptible strains, No13 strain contained one point mutation (T2289C), No17 had two point mutations (G2224A, T2289C) and No22 strain had 3 point mutations (G2224A, C2245T, T2289C).The MICs of the 3 resistant Hp isolates were as follows: No13 of 8.0 mg/L, No17 of 64 mg/L, No22 of >256 mg/L. With increase of the resistance of Hp strains, the number of point mutations increased.

CONCLUSION

The point-mutations at 23 S rRNA gene responsible for Hp resistance to clarithromycin have not been reported in literature either at home or abroad, demonstrating that different mechanism of Hp resistance to clarithromycin exists in different regions.

Cloning, sequencing and bioinformatics analysis of adhesin gene babA2 of Helicobacter pylori

AIM

To obtain DNA of human Helicobacter pylori (Hp) adhesin gene babA₂ and the amplified fragment was inserted into plasmid pET-22b (+) for nucleotide sequencing analysis and to carry out bioinformatics analysis.

METHODS

The babA₂ DNA was amplified by PCR and inserted into the plasmid pET -22b (+) and sequenced. The biological property was analysed by the software ANTHEPROT V4.3c.

RESULTS

DNA sequencing analysis showed that the sequence of babA₂ DNA was the same as that published by GenBank. ANTHEPROT V4.3c software predicted its relative molecular mass(M_r) was 78 kD and it possessed good antigencity and hydrophobicity.

CONCLUSION

A confirmed babA₂ gene has been obtained and bioinformatics analysis showed that it had good immunogenicity. Our study lays a good foundation for recombination, expression and relevant research on adhesin gene babA2 of Helicobacter pylori.

cagA and vacA genotype of Helicobacter pylori associated with gastric diseases in Xi’an area

AIM: To establish stock of clinical Helicobacter pylori (H. pylori) isolates, to perform cagA and vacA typing of these isolates, to evaluate the relationship between genotypes of cagA and vacA and upper gastrointestinal diseases and to assess the association of vacA genotypes with presence of the pathogenicity marker-cagA.

METHODS: Clinical H.pylori strains were isolated from the antrum of 259 patients in Clumbia agar. The isolated H. pylori strains were identified by histology, and16SrRNA PCR. CagA genotypes were detected by colony hybridization, the probe was derived from the cloned plasmid PcagA, and digested by EcoRI-HindIII and the isolated PcagA DNA fragment was radioactively labelled by the random priming method. vacA genes types (s,m)and subtypes (s1a, s1b, s2) were typed by PCR. Vacuolating toxin was detected with neutral red absorb test. The results were treated statistically by χ² test, t test, and rank sum test.

RESULTS: A total of 192 clinical H.pylori strains were isolated and the stock of Helicobacter pylori was established. The total positive rate of cagA was 87% in all gastric diseases, and 95% in gastric cancer group. There was a difference between gastric cancer group and the other groups (P < 0.05) except duodenal ulcer group. The expression of type s1 of vacA was more than type s2 (P < 0.05), and, the expression of type m1 was equal to type m2. In gastric cancer group, there was a difference between s1a and s1b (P < 0.05), and s1a was more than s1b. Vacuolating toxins were more in Xi’an area isolates.

CONCLUSION: The cagA⁺ vacA type s1 clinical isolates are more in Xi’an area, but this can not serve as an index to predict gastric cancer.

N/A

N/A

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma in gastroscopic biopsy

AIM: To explore and discuss the clinicopathologic characteristics of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroscopic biopsy specimen.

METHODS: A retrospective study of 26 cases of lymphoma diagnosed by gastroscopic biopsy during 1999 to 2001 from gastroscopy files of Xijing Hospital was made. The diagnostic criteria were adopted according to the new classification of non-Hodgkin's lymphoma.

RESULTS: Twenty-six cases of primary gastric lymphoma consisting of 15 men and 11 women, aged between 23 to 76 years were recruited from 6225 cases who received gastroscopy. All of them were diagnosed by both endoscopic findings and histological examinations. Histologically, 23 cases were MALToma (low grade) and 3 cases lymphoblastic lymphoma (high grade). Immunohistochemically, all cases were CD20 positive, while CK and EMA were negative.

CONCLUSION: The majority of the cases of primary low-grade gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa associated lymphoid tissue.

Influence of expression of matrix metalloproteinase induced by H. pylori infection in gastric cancer cell line

AIM

To establish an animal model to study the effect of H. pylori on metastasis, and to explore the possible mechanism and the relationship between H. pylori and gastric cancer metastasis.

METHODS

Using BGC-823 cell cocultured with H. pylori, the growth of tumors and metastasis were observed in 8-week nude mice after the first intraumoral injection of the group of H.pylori infection and the group of no infection. The expression of MMP-2, MMP-3, TIMP-2 and TIMP-3 were investigated by immunohistochemical staining.

RESULTS

There was a significant difference in the weight of tumors between the group of H.pylori infection and the group without H.pylori infection in 8-week nude mice after the first intratumoral injection (P<0.05). There were two lung metastases in group of H. pylori infection. The positive rates of MMP-2, MMP-3, TIMP-2 and TIMP-3 in the group of H. pylori infection by immunohischemical staining were 77.8±9.6%, 64.5±6.9%, 57.6±12.2% and 40.0±9.2%, and 61.2±9.7%, 53.1±5.8%, 54.3±10.9% and 53.0±6.6% in the group without H.pylori infection, respectively. The expression of MMP-2, MMP-3 and TIMP-2 were significantly higher in the group of H. pylori infection than those in the group without H.pylori infection (P<0.05), but the expression of TIMP-3 has no significantly change.

CONCLUSION

H.pylori infection can accelerate the tumor growth in nude mouse and lung metastasis. The expression of MMP-2 and MMP-3 increases and TIMP-2 decreases in H. pylori infection, suggesting H. pylori may enhance gastric cancer metastasis by regulating the expression of metastasis-correlated factors.

Recombinant Helicobacter pylori catalase

AIM: To construct a recombinant strain which highly expresses catalase of Helicobacter pylori (H. pylori) and assay the activity of H. pylori catalase.

METHODS: The catalase DNA was amplified from H. pylori chromosomal DNA with PCR techniques and inserted into the prokaryotie expression vector pET-22b (+), and then was transformed into the BL21 (DE3) E. coli strain which expressed catalase recombinant protein. The activity of H. pylori catalase was assayed by the Beers&Sizers.

RESULTS: DNA sequence analysis showed that the sequence of catalase DNA was the same as GenBank’s research. The catalase recombinant protein amounted to 24.4% of the total bacterial protein after induced with IPTG for 3 hours at 37 °C and the activity of H. pylori catalase was high in the BL21 (DE3) E. coli strain.

CONCLUSION: A clone expressing high activity H. pylori catalase is obtained, laying a good foundation for further studies.

Construction of clone expressing adhesin Hsp60 of Helicobacter pylori

AIM

To construct a recombinant vector containing gene encoding Hsp60 gene of Helicobacter pylori and to express the vector in E.coli BL21.

METHODS

The Hsp60 gene was amplified from H.pylori chromosome by PCR and inserted into the prokaryotie expression vector pET-22b (+). The recombinant vector was transformed and expressed in E.coli BL21 (DE3). Recombinant Hsp60 protein immunogenicity was studied by Western blot.

RESULTS

The 1.6 kb Hsp60 gene was successfully isolated. Recombinant E.coli strains expressed Hsp60 were obtained, the expression protein amounted to 27.2% of the total bacterial protein after induced with IPTG for 3 h at 37 ℃, which included inclusion body and soluble protein. Inclusion body was the major pattern of the expression that amounted to 76.6% of the insoluble protein. Western blot analysis of rHsp60 confirmed that it could be specially recognized by serum from Hp infected patients.

CONCLUSION

The gene coding for Hp Hsp60 is cloned and expressed successfully. The results obtained lay the foundation for constructing the H.pylori vaccine.

Overexpression of c-fos in Helicobacter pylori-induced gastric precancerosis of Mongolian gerbil

AIM: To explore dysregulation of c-fos in several human malignancies, and to further investigate the role of c-fos in Helicobacter pylori (H. pylori)-induced gastric precancerosis.

METHODS: Four-week-old male Mongolian gerbils were employed in the study. 0.5 mL 1 × 10⁸ cfu·L^-1 suspension of H. pylori NCTC 11637 in Brucella broth were inoculated orally into 20 Mongolian gerbils. Another 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non-infected control gerbils were sacrificed at 25 and 45 weeks after infection. The stomach of each gerbil was removed and opened for macroscopic observation. The expression of c-fos was analyzed by RT-PCR and immunohistochemical studies in H. pylori-induced gastric precancerosis of Mongolian gerbil. Half of each gastric antrum mucosa was dissected for RNA isolation and RT-PCR. β-actin was used as the housekeeping gene and amplified with c-fos as contrast. PCR products of c-fos were analyzed by gel image system and the level of c-fos was reflected with the ratio of c-fos/β-actin. The immunostaining for c-fos was conducted using monoclonal antibody of c-fos and the StreptAvidin-Biotin-enzyme Complex kit.

RESULTS: H. pylori was constantly found in all infected animals in this study. After infection of H. Pylori for 25 weeks, ulcers were observed in the antral and the body of stomach of 60% infected animals (6/10). Histological examination showed that all animals developed severe inflammation, especially in the area close to ulcers, and multifocal lymphoid follicles appeared in the lamina propria and submucosa. After infection of H. Pylori for 45 weeks, severe atrophic gastritis in all infected animals, intestinal metaplasia in 80% infected animals (8/10) and dysplasia in 60% infected animals (6/10) could be observed. C-fos mRNA levels were significantly higher after infection of H. pylori for 25 weeks (1.84 ± 0.79), and for 45 weeks (1.59 ± 0.37) than those in control-animals (0.74 ± 0.22, P < 0.01). C-fos mRNA levels were increased 2.5-fold by 25th week (P < 0.01) and 2.1-fold by 45th week (P < 0.01) in precancerosis induced by H. pylori, when compared with normal gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of c-fos. Furthermore, there was a sequential increase in c-fos positive cells from normal epithelium to precancerosis.

CONCLUSION: The study suggested that overexpression of c-fos occurs relatively early in gastric tumorigenesis in this precancerosis model induced by H. pylori.

L-forms of H. pylori

AIM: To study the occurrence of L-forms of H. pylori infection in patients with peptic ulcers and its association with possible changes of cellular immune function in the patients.

METHODS: Endoscopic biopsy specimens of gastric antrum and gastric corpus were taken from 228 patients with peptic ulcers and inoculated into Skirrow selective medium for H. pylori vegetative forms and special medium for H. pylori L-forms, followed by bacterial isolation and identification. And peripheral venous blood of the patients was taken to detect the percentage of CD3⁺, CD4⁺ and CD8⁺ with biotin-streptavidin (BSA) and the level of IL-2, IL-6 and IL-8 with ELISA.

RESULTS: (1) The detection rates of H. pylori L-forms and vegetative forms in the patients were 50.88% (116/228) and 64.91% (148/228) respectively, and the co-infection rate of H. pylori L-forms and vegetative forms was 78.38% (116/148). To be more exact, the detection rates of H. pylori L-forms in male and female patients were 57.04% (77/135) and 41.94% (39/93) respectively, and statistics found significant difference between them (P < 0.05). Furthermore, the detection rates of H. pylori L-forms in patients aged 14 years-, 30 years-, 40 years- and 50 years- were 31.91% (15/47), 42.86% (24/56), 56.94% (41/72) and 67.92% (36/53) respectively, and there was significant difference between them (P < 0.01). (2) The percentages of CD3⁺, CD4⁺, CD8⁺, the ratio of CD4⁺/CD8⁺, and the level of IL-2, IL-6, IL-8 in H. pylori-positive patients were (52.59 ± 5.44)%, (35.51 ± 5.74)%, (27.77 ± 8.64)%, (1.56 ± 0.51), (2.66 ± 0.47) mg/L, (108.62 ± 5.85) ng/L and (115.79 ± 7.18) ng/L respectively, compared with those in H. pylori-negative patients, the percentages of CD3⁺, CD4⁺ and the ratio of CD4⁺/CD8⁺ decreased, but the level of IL-2, IL-6 increased, and the difference was significant (P < 0.001-P < 0.01). Moreover, the percentages of CD3⁺, CD4⁺, CD8⁺, the ratio of CD4⁺/CD8⁺, and the level of IL-2, IL-6, IL-8 in the patients with mixed infection of both H. pylori L-forms and vegetative forms were (51.69±5.28)%, (34.75 ± 5.89)%, (27.15 ± 7.45)%, (1.48 ± 0.47), (2.16 ± 0.38) mg/L, (119.45 ± 5.44) ng/L and (123.64 ± 6.24) ng/L respectively, compared with those in patients with simple infection of H. pylori vegetative forms, the percentage of CD4⁺, the ratio of CD4⁺/CD8 ⁺ and the level of IL-2 increased, but the level of IL-6 and IL-8 decreased, statistical difference was found between them (P < 0.001-P < 0.05).

CONCLUSION: L-forms variation often occurs in patients with peptic ulcers who are infected by H. pylori, which is commonly found in male patients and related to ages. The L-forms variation of H. pylori can be an important factor causing disorder of cellular immune function in the patients with peptic ulcers who are infected by H. pylori.

Association of cyclooxygenase-2 expression with Hp-cagA infection in gastric cancer

AIM: To observe the expression of cyclooxygenase-2 (COX-2) and to investigate the association between COX-2 expression and infection with cytotoxic-associated gene A (cagA) positive strain Helicobacter pylori (Hp) in human gastric cancer, and subsequently to provide fresh ideas for the early prevention of gastric cancer.

METHODS: 32 Specimens of gastric cancer and corresponding adjacent normal gastric mucosa were obtained from patients who had undergone surgical operations of gastric cancer. All the samples including 1 case of stomach malignant lymphoma and 31 cases of gastric adenocarcinoma were confirmed by pathology diagnosis. The expression of COX-2 in 32 specimens of gastric cancer and corresponding adjacent normal gastric mucosa was quantitatively determined and analyzed with Flow Cytometry, and the levels of COX-2 protein were compared between specimens with cagA⁺Hp infection and those without cagA⁺Hp infection. The cagA gene in 32 specimens of gastric cancer was detected by polymerase chain reaction (PCR) method.

RESULTS: Twenty-seven of 32 (84%) specimens of gastric cancer showed over-expression of COX-2, compared with the adjacent normal gastric mucosa. cagA⁺ gene were detected from 19 specimens of gastric cancer, but not from the other 13 specimens. The levels of COX-2 protein in 19 specimens of gastric cancer with cagA⁺Hp infection (the number of positive cells was 73.82 ± 18.2) were significantly higher than those in the 13 specimens without cagA⁺Hp infection (the number of positive cells was 35.92 ± 22.1).

CONCLUSION: COX-2 is overexpressed in gastric cancer and cagA⁺Hp infection could up-regulate the expression of COX-2 in gastric cancer in human. There may also exist another way or channel to regulate the expression of COX-2 in gastric cancer in addition to cagA⁺Hp infection. Therefore, applying COX-2 selective inhibitors could be an effective and promising way to prevent gastric cancer.

Effect of Helicobacter pylori infection on bax protein expression in patients with gastric precancerous lesions

AIM: To evaluate the effect of Helicobacter pylori (H. pylori) infection on bax protein expression, and explore the role of H. pylori in the development of gastric carcinoma.

METHODS: H. pylori was examined by rapid urease test and Warthin-Starry method, and bax protein was examined by immunohistochemical staining in 72 patients with pre-malignant lesions.

RESULTS: Bax protein was expressed with different degree in intestinal metaplasia and gastric dysplasia, its positive rate being 63.9%. The positive rate of Bax protein expression in H. pylori-positive gastric precancerous lesions (72.3%) was significantly higher than that in H. pylori-negative gastric precancerous lesions (48.0%, x² = 4.191, P < 0.05). H. pylori infection was correlated well with the expression of Bax protein in gastric precancerous lesions(r = 0.978, P < 0.01). After eradication of H. pylori, the positive rate of bax protein expression was significantly decreased in H. pylori-positive gastric precancerous lesions(x² = 5.506, P < 0.05). In the persistent H. pylori infected patients, the positive rate of Bax protein expression was not changed.

CONCLUSION: H. pylori is involved in the expression of Bax gene. H. pylori infection increases the expression of Bax protein, this may be one of the mechanisms of H. pylori infection in the induction of gastric epithelial cell apoptosis. H. pylori might act as a tumor promoter in the genesis of gastric carcinoma. Eradication of H. pylori could inhibit the formation and development of gastric carcinoma.

Helicobacter pylori infection generated gastric cancer through p53-Rb tumor-suppressor system mutation and telomerase reactivation

AIM

To investigate the relationship between Helicobacter pylori (H.pylori) infection and the expressions of the p53, Rb, c-myc, bcl-2 and hTERT mRNA in a series of diseases from chronic gastritis (CG), intestinal metaplasia type I or II(IMI-II), intestinal metaplasia type III (IMIII), mild or modest dysplasia (DysI-II), severe dysplasia (DysIII) to gastric cancer(GC) and to elucidate the mechanism of gastric carcinogenesis relating to H.pylori infection.

METHODS

272 cases between 1998 and 2001 were available for the study including 42 cases of CG, 46 cases of IMI-II, 25 cases of IMIII, 48 cases of DysI-II, 27 cases of DysIII, 84 cases of GC. H.pylori infection and the expressions of p53, Rb, c-myc, bcl-2 were detected by means of streptavidin-peroxidase (SP) immunohistochemical method. HTERT mRNA was detected by in situ hybridization (ISH).

RESULTS

The expressions of p53, Rb, c-myc, hTERT mRNA and bcl-2 were higher in the GC than in CG, IM, Dys. The expression of c-myc was higher in IMIII with H.pylori infection (10/16) than that without infection (1/9) and the positive rate in DysI-II and DysIII with H.pylori infection was 18/30 and 13/17, respectively, higher than that without infection (4/18 and 3/10, respectively). In our experiment mutated p53 had no association with H.pylori infection, the expression of Rb was associated with H.pylori infection in GC, but the p53-Rb tumor-suppressor system abnormal in DysI-II cases, DysIII and GC cases with H.pylori infection was 21/30, 15/17 and 48/48 respectively, higher than non-infection groups (4/18, 3/10, 28/36). Furthermore the level of hTERT mRNA in GC with H.pylori infection (47/48) was higher than that without infection (30/36), however the relationship between bcl-2 and H.pylori was only in IMIII. C-myc had a close association with hTERT mRNA in DysIII and GC (P=0.0 253,0.0 305 respectively).

CONCLUSION

In the gastric carcinogenesis, H.pylori might cause the severe imbalance of proliferation and apoptosis in the precancerous lesions (IMIII and GysIII) first, leading to p53-Rb tumor-suppressor system mutation and telomerase reactivation, and finally causes gastric cancer.

PELA microspheres loaded H. pylori lysates and their mucosal immune response

AIM: To prepare poly (D,L-lactide)-polyethylene glycol copolymer (PELA) microspheres loaded H.pylori lysates or Cystografin and observe their targeting in gastrointestinal mucous membrane or analyze the mucosal immune responses by oral administration.

METHODS: PELA microspheres loaded H.pylori lysates or Cystografin were prepared by double emulsion evaporation method. Their distribution in gastrointestinal mucous membrane was observed by CT.Balb/c mice orally immunized in mucosal immune responses, whose antibody production in salivary and gut washing and antibody secreting cells in Peyer’s patches (PP) were estimated by ELISA and ELISPOT, respectively. The microspheres’ physical properties, such as particle size, protein level and morphology were investigated.

RESULTS: All prepared microspheres were found to have a smooth surface morphology from 3.20-4.05 μm in diameter and high encapsulation efficiency from 74.9%-82.2%. No significant correlation in their physical properties was shown, depending on their molecular weight at the similar composition ratio. Immunization with all types of PELA-Hp microspheres elevated the saliva sIgA level at week 3 by approximately 3-4 times that with soluble antigen, which was greatly enhanced after boosting. At one week after last immunization with all types of PELA-Hp microspheres (week 8), the specific sIgA-ASCs, IgG-ASCs and sIgA in salivary rose obviously. In intestinal Peyer’s patches, the specific sIgA-ASCs were 5.92-6.98 × 10⁴/mL cell and IgG-ASCs were 3.47-4.02 × 10⁴/mL cell, about 5-9 times higher than those with soluble antigen (P < 0.01). ASCs in intestine were more than those in stomach and the majority of the ASCs were sIgA-ASCs. The sIgA in gut washing fluid was 1.62-1.85 OD, about 3-6 times tthat of those with soluble antigen. There were significant differences of the ASCs and sIgA in gut washing fluid as compared with those of PBS and MS-0 (P < 0.05). There appeared to be good correlation between sIgA level in gut washing fluid and sIgA-ASCs in intestinal Peyer’s patches.

CONCLUSION: PELA microspheres may be used as vehicle to delivery antigen and adjuvant in designing oral vaccination.

Overexpression of cyclin E in Mongolian gerbil with Helicobacter pylori- induced gastric precancerosis

AIM: To explore dysregulation of cyclin E in malignancies, and to further investigate the role of cyclin E in Helicobacter pylori (H. pylori)-induced gastric precancerosis.

METHODS: Four-week-old specific pathogen-free male Mongolian gerbils were employed in the study. 0.5 mL 1 × 10⁸ cfu·L^-1 suspension of H. pylori NTCC11637 in Brucella broth was inoculated orally into each of 20 Mongolian gerbils, and a further 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non-infected control gerbils were sacrificed at 25, 45 wk after infection. The expression of cyclin E was analyzed by RT-PCR and immunohistochemical studies with monoclonal antibody to cyclin E in Mongolian gerbil of H. pylori-induced gastric precancerosis.

RESULTS: H. pylori was constantly detected in all infected animals throughout the study. At 25 wk after infection of H. pylori. ulcers were observed in the antral and body of stomach (n = 6). Histological examination showed that all animals developed severe inflammation and multifocal lymphoid follicles appeared in the lamina propria and submucosa of gastric antrum. At 45 wk after infection of H. pylori, severe atrophic gastritis (n = 10). intestinal metaplasia (n = 8) and dysplasia (n = 6) could be observed. Cyclin E mRNA levels were significantly more at 25 wk after infection of H. pylori (1.27 ± 0.26), and at 45 wk after infection of H. pylori ( 1.82 ± 0.39) than control-animals (0.59 ± 0.20,P < 0.01); cyclin E mRNA levels were evaluated by 2.2-fold at 25 wk (P < 0.01) and 3.1-fold at 45 wk (P < 0.01) precancerosis induced by H. pylori, when compared with control gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of cyclin E. Furthermore, there was a sequential increase in cyclin E positive cells from normal epithelium to precancerosis.

CONCLUSION: Overexpression of cyclin E occurs relatively early in gastric tumorigenesis in this model.

Polymorphism of flagellin A gene in Helicobacter pylori

AIM: To study the polymorphism of flagellin A genotype and its significance in Helicobacter pylori (H. pylori).

METHODS: As the template, genome DNA was purified from six clinical isolates of H. pylori from outpatients, and the corresponding flagellin A fragments were amplified by polymerase chain reaction. All these products were sequenced. These sequences were compared with each other, and analyzed by software of FASTA program.

RESULTS: Specific PCR products were amplified from all of these H. pylori isolates and no length divergence was found among them. Compared with each other, the highest ungapped identity is 99.10%, while the lowest is 94.65%. Using FASTA program, the alignments between query and library sequences derived from different H. pylori strains were higher than 90%.

CONCLUSION: The nucleotide sequence of flagellin A in H. pylori is highly conservative with incident divergence. This information may be useful for gene diagnosis and further study on flagellar antigen phenotype.

Apoptosis, proliferation and p53 gene expression of H. pylori associated gastric epithelial lesions

AIM: To study the relationship between Helicobacter pylori (H. pylori) and gastric carcinoma and its possible pathogenesis by H. pylori.

METHODS: DNEL technique and immunohistochemical technique were used to study the state of apoptosis, proliferation and p53 gene expression. A total of 100 gastric mucosal biopsy specimens, including 20 normal mucosa, 30 H. pylori-negative and 30 H. pylori-positive gastric precancerous lesions along with 20 gastric carcinomas were studied.

RESULTS: There were several apoptotic cells in the superficial epithelium and a few proliferative cells within the neck of gastric glands, and no p53 protein expression in normal mucosa. In gastric carcinoma, there were few apoptotic cells, while there were a large number of proliferative cells, and expression of p53 protein significantly was increased. In the phase of metaplasia, the apoptotic index (AI, 4.36% ± 1.95%), proliferative index (PI, 19.11% ± 6. 79%) and positivity of p53 expression (46.7%) in H. pylori-positive group were higher than those in normal mucosa (P < 0.01). AI in H. pylori-positive group was higher than that in H. pylori-negative group (3.81% ± 1.76%), PI in H. pylori-positive group was higher than that in H. pylori-negative group (12.25% ± 5.63%, P < 0.01). In the phase of dysplasia, AI (2.31% ± 1.10%) in H. pylori-positive group was lower (3.05% ± 1.29%) than that in H. pylori-negative group, but PI (33.89% ± 11.65%) was significantly higher (22.09% ± 80.18%, P < 0.01). In phases of metaplasia, dysplasia and gastric cancer in the H. pylori-positive group, AIs had an evidently graduall decreasing trend (P < 0.01), while PIs had an evidently gradual increasing trend (P < 0.05 or P < 0.01), and there was also a trend of gradual increase in the expression of p53 gene.

CONCLUSION: In the course of the formation of gastric carcinoma, proliferation of gastric mucosa can be greatly increased by H. pylori, and H. pylori can induce apoptosis in the phase of metaplasia, but in the phase of dysplasia H. pylori can inhibit cellular apoptosis. And H. pylori infection can strengthen the expression of mutated p53 gene.

Fish sauce and gastric cancer: an ecological study in Fujian Province, China

AIM: To explore the relationship between consumption of fish sauce and the risk of gastric cancer in Fujian Province.

METHODS: An ecological study was carried out. A total of 11000 subjects from 55 townships were randomly selected from 10 counties within Fujian Province. All subjects were local residents who had been living in Fujian Province for more than 20 years, within the age group of 45-74 years. Trained interviewers conducted face-to-face interviews with a standardized questionnaire, which covered the frequency and amount of food intake, dietary habit, tobacco and alcohol consumption and history of chronic gastric diseases. Univariate and multivariate analyses were performed using Epi-info and SAS statistical packages, respectively.

RESULTS: A significant correlation between monthly consumption of fish sauce and mortality of gastric cancer was found. Pearson’s coefficient of correlation was statistically significant with r = 0.7356 for males, r = 0.5246 for females (P < 0.01). In the multivariate analysis, consumption of fish sauce still showed an association with the risk of gastric cancer. No significant positive correlation between esophagus cancer, liver cancer, colon cancer and consumption of fish sauce were observed.

CONCLUSION: Long-term intake of fish sauce may be related to high mortality of gastric cancer. Consumption of fish sauce might be one of important and unique etiologic factors of gastric cancer in Fujian Province. Further studies are needed to confirm this ecological study.

Ascorbic acid secretion in the human stomach and the effect of gastrin

AIM: To investigate the changes of gastric mucosal ascorbic acid secretion in patients with nonulcer dyspepsia and the effect of gastrin on it, and to relate any observed changes to H. pylori infection and mucosal histology.

METHODS: Ascorbic acid secretions in patients were examined by collecting continuously gastric juice for one hour after having aspirated and discarded fasting gastric juice. Using the clearance rate (mL/min) of ascorbic acid from blood to gastric juice represented ascorbic acid secretion in the gastric mucosa. Ascorbic acid concentrations in plasma and juice were measured by ferric reduced method.

RESULTS: Gastric ascorbic acid secretions in H. pylori -positive patients (1.46 mL/min, range 0.27-3.78) did not significantly differ from those in H. pylori -negative patients (1.25 mL/min, 0.47-3.14) (P > 0.05). There were no significant differences in ascorbic acid secretions between patients with mild (1.56 mL/min, 0.50-3.30), moderate (1.34 mL/min, 0.27-2.93) and severe (1.36 mL/min, 0.47-3.78) inflammation (P > 0.05). There were no significant differences in ascorbic acid secretions between patients without activity (1.45 mL/min, 0.27-3.14) and with mild (1.32 mL/min, 0.61-2.93), moderate (1.49 mL/min, 0.50-3.78) and severe (1.43 mL/min, 0.51-3.26) activity of chronic gastritis either (P > 0.05). Ascorbic acid secretions in patients with severe atrophy (0.56 mL/min, 0.27-1.20) were markedly lower than those in patients with out atrophy (1.51 mL/min, 0.59-3.30) and with mild (1.43 mL/min, 0.53-3.78) and moderate (1.31 mL/min, 0.47-3.16) atrophy (P < 0.005). There was a significant negative correlation between ascorbic acid secretion and severity of atrophy (correlation coefficient = -0.43, P < 0.005). After administration of pentagastrin, ascorbic acid secretions were markedly elevated (from 1.39 mL/min, 0.36-2.96 to 3.53 mL/min, 0.84-5.91) (P < 0.001).

CONCLUSION: Ascorbic acid secretion in gastric mucosa is not affected by H. pylori infection. Gastric ascorbic acid secretion is markedly related to the severity of atrophy, whereas not related to the severity of inflammation and activity. Gastrin may stimulate gastric ascorbic acid secretion. A decreased ascorbic acid secretion may be an important factor in the link between atrophic gastritis and gastric carcinogenesis.