Association of Helicobacter pylori infection with gastric carcinoma: a meta-analysis

OBJECTIVE

As conflicting studies have recently been published, we aimed to determine if Helicobacter pylori (H. pylori) infection is associated with gastric adenocarcinoma.

METHODS

This was a meta-analysis of observational epidemiological studies.

RESULTS

A total of 42 studies met the selection criteria and were categorized by the type of study design: eight cohort and 34 case-control studies. The pooled odds ratio for H. pylori in relation to gastric carcinoma was 2.04 (95% CI: 1.69-2.45). Both patient age (OR 0.77, 95% CI: 0.68-0.89) and intestinal type cancers (OR 1.14, 95% CI: 1.05-1.25) were independent effect modifiers. Analysis of other effect modifiers showed no relationship with female gender (OR 0.76, 95% CI: 0.64-0.89), stage of cancer (advanced %) (OR 1.12, 95% CI: 0.88-1.43), anatomical location (cardia %) (OR 1.54, 95% CI: 0.32-7.39) or cohort (nested case-control) studies (OR 1.72, 95% CI: 0.32-9.17). There was significant heterogeneity among the studies (tau2 = 149; p < 0.001). The quality of the studies varied considerably, with the majority of excellent studies producing positive results and the very poor to moderate studies producing mixed results.

CONCLUSIONS

H. pylori infection is associated with a 2-fold increased risk of developing gastric adenocarcinoma.

Apoptosis in gastric epithelium induced by Helicobacter pylori infection: implications in gastric carcinogenesis

OBJECTIVES

Helicobacter pylori is an identified carcinogen for gastric cancer, however, the underlying mechanisms remain to be defined. In this review, we sought to elucidate the role of apoptosis in gastric carcinogenesis, to determine the influence of H. pylori infection on apoptosis, and finally to provide insights into the mechanisms by which H. pylori may lead to gastric carcinogenesis.

METHODS

A broad-based MEDLINE and Current Contents literature search was performed to identify relevant publications between 1966 and March 2000 addressing H. pylori infection, apoptosis, cell proliferation, gastric carcinoma, oncogenes, and tumor suppressor genes, as well as the products of these genes. Abstracts from recent major conferences that provided adequate additional data were also included.

RESULTS

Apoptotic cells are rare in the glandular neck region (the generative cell zone) of normal gastric mucosa. With progression of atrophic gastritis, the generative cell zone shifts downward and a relatively large number of apoptotic cells occur. In intestinalized glands, both apoptotic cells and proliferative cells are present in deeper portions of the glands, corresponding to the generative zone. A higher frequency of apoptosis has been observed in gastric dysplasia than in coexisting gastric carcinomas, whereas the number of proliferative cells is significantly higher in gastric carcinoma than in dysplasia. Upregulation of oncogene bcl-2 in premalignant lesions and "downregulation" of the gene after malignant change is probably a common event. Accumulation of p53 protein is first detected in dysplasia, although mutation of the pS3 gene may occur in intestinal metaplasia. H. pylori infection induces apoptosis in gastric epithelial cells, which returns to normal after eradication of the infection. Numerous molecules produced by H. pylori including cytotoxin (VacA), lipopolysaccharide, monochloramine, and nitric oxide may directly induce apoptosis. Moreover, H. pylori-stimulated host inflammatory/immune responses lead to release of a large amount of cytokines. Cytokines produced by type 1 T helper cells, such as TNF-alpha and IFN-gamma, markedly potentiate apoptosis. Gastric cell proliferation is significantly higher in patients with H. pylori infection than in normal controls, and eradication of the infection leads to a reduction in cell proliferation. Apoptosis and cell proliferation are also increased in precancerous lesions such as gastric atrophy, intestinal metaplasia, and dysplasia in the presence of H. pylori infection. However, H. pylori-induced apoptosis may no longer be cell cycle-dependent in these lesions because of the occurrence of alterations and mutations of apoptosis-regulating genes, resulting in a loss of balance between apoptosis and cell proliferation.

CONCLUSIONS

It is hypothesized that H. pylori-induced apoptosis may play a key role in gastric carcinogenesis by increasing cell proliferation and/or resulting in gastric atrophy.

Antral-type mucosa in the gastric incisura, body, and fundus (antralization): a link between Helicobacter pylori infection and intestinal metaplasia?

OBJECTIVES

Helicobacter pylori is a carcinogen; gastric carcinoma involves a multistep process from chronic gastritis to atrophy, intestinal metaplasia, and dysplasia. The aims of this study were to determine the types of mucosa at different gastric sites in H. pylori-infected and uninfected patients, and whether the presence of antral-type mucosa in the incisura, body, and fundus is associated with gastric atrophy and intestinal metaplasia.

METHODS

Two hundred and sixty-eight patients with dyspepsia were enrolled. Eight biopsies (i.e., antrum x3, body x2, fundus x2, and incisura x1) were obtained. One antral biopsy was used for the CLO-test. Three (each from the antrum, body, and fundus) were cultured. The remaining biopsies were examined histologically according to the updated Sydney System after staining with hematoxylin and eosin and Giemsa. A validated serological test was also applied.

RESULTS

Overall, 113 (42%) patients were infected with H. pylori. At the incisura, antral-type mucosa was more prevalent in infected than in uninfected patients (84% vs. 18%; odds ratio [OR] = 23.9, 95% confidence interval [CI] 12.5-45.8; p<0.001). Atrophic gastritis and intestinal metaplasia at the incisura was present in 19.5% and 13.3%, respectively, of infected, and 4.5% and 3.2%, respectively, of uninfected patients (both p<0.01). Moreover, atrophic gastritis at the incisura was associated with the presence of antral-type mucosa at the site (termed antralization); the prevalence of atrophic gastritis was 19.5% (24/123) in the presence of antralization, whereas the rate was 2.1% (3/145) without antralization (OR = 11.4, 95% CI 3.4-39.2; p<0.001). Similarly, at the incisura, 16.3% (20/123) of "antralized" cases and 1.4% (2/145) of "unantralized" cases had intestinal metaplasia (OR = 13.8, 95% CI, 3.2-60.7; p<0.001). The association between antralization at gastric body and fundus also appeared to be associated with atrophic gastritis and intestinal metaplasia at these sites.

CONCLUSIONS

Atrophic gastritis and intestinal metaplasia occurs predominantly at the gastric antrum and incisura with H. pylori infection. Antralization of the gastric incisura is a common event in H. pylori-infected patients, and appears to be associated with an increased risk of atrophic gastritis and intestinal metaplasia.

Helicobacter pylori infection is not associated with diabetes mellitus, nor with upper gastrointestinal symptoms in diabetes mellitus

OBJECTIVE

The association between Helicobacter pylori (H. pylori) infection and diabetes mellitus is controversial. We aimed to determine the prevalence of H. pylori infection in patients with diabetes and nondiabetic controls, and assess whether H. pylori infection was associated with upper gastrointestinal (GI) symptoms in diabetes mellitus.

METHODS

A total of 429 patients with type 1 (n = 49) or type 2 (n = 380) diabetes mellitus (48.6% women, mean age 60.7 yr) and 170 nondiabetic controls (34.7% women, mean age 60.4 yr) were evaluated. All subjects completed a validated questionnaire (the Diabetes Bowel Symptom Questionnaire) to determine upper GI symptoms, and a blood sample was tested for H. pylori infection using a validated ELISA kit (sensitivity 96%, specificity 94%).

RESULTS

Seroprevalence of H. pylori was 33% and 32%, respectively, in patients with diabetes and controls (NS). In both groups, the seroprevalence was significantly higher in men than in women; 39% vs 25% (p = 0.002) in diabetic patients, and 40% vs 20% (p = 0.01) in controls. Patients with diabetes had a significantly higher prevalence of early satiety (OR = 2.30), fullness (OR = 3.15), and bloating (OR = 1.50) compared with controls. Upper GI symptoms were present in 49% of H. pylori-positive and 53% of H. pylori-negative patients with diabetes (OR = 0.87, 95% CI 0.58-1.31, p = 0.56). H. pylori infection was also not associated with any of the individual upper GI symptoms before or after adjustment for potential confounding factors. However, patient age and female gender were identified as independent risk factors for upper GI symptoms. Smoking was a risk factor for bloating and early satiety.

CONCLUSIONS

H. pylori infection appears not to be associated with diabetes mellitus or upper GI symptoms in diabetes mellitus.

Apoptosis in gastric epithelium induced by Helicobacter pylori infection: implications in gastric carcinogenesis

OBJECTIVES

Helicobacter pylori is an identified carcinogen for gastric cancer, however, the underlying mechanisms remain to be defined. In this review, we sought to elucidate the role of apoptosis in gastric carcinogenesis, to determine the influence of H. pylori infection on apoptosis, and finally to provide insights into the mechanisms by which H. pylori may lead to gastric carcinogenesis.

METHODS

A broad-based MEDLINE and Current Contents literature search was performed to identify relevant publications between 1966 and March 2000 addressing H. pylori infection, apoptosis, cell proliferation, gastric carcinoma, oncogenes, and tumor suppressor genes, as well as the products of these genes. Abstracts from recent major conferences that provided adequate additional data were also included.

RESULTS

Apoptotic cells are rare in the glandular neck region (the generative cell zone) of normal gastric mucosa. With progression of atrophic gastritis, the generative cell zone shifts downward and a relatively large number of apoptotic cells occur. In intestinalized glands, both apoptotic cells and proliferative cells are present in deeper portions of the glands, corresponding to the generative zone. A higher frequency of apoptosis has been observed in gastric dysplasia than in coexisting gastric carcinomas, whereas the number of proliferative cells is significantly higher in gastric carcinoma than in dysplasia. Upregulation of oncogene bcl-2 in premalignant lesions and "downregulation" of the gene after malignant change is probably a common event. Accumulation of p53 protein is first detected in dysplasia, although mutation of the pS3 gene may occur in intestinal metaplasia. H. pylori infection induces apoptosis in gastric epithelial cells, which returns to normal after eradication of the infection. Numerous molecules produced by H. pylori including cytotoxin (VacA), lipopolysaccharide, monochloramine, and nitric oxide may directly induce apoptosis. Moreover, H. pylori-stimulated host inflammatory/immune responses lead to release of a large amount of cytokines. Cytokines produced by type 1 T helper cells, such as TNF-alpha and IFN-gamma, markedly potentiate apoptosis. Gastric cell proliferation is significantly higher in patients with H. pylori infection than in normal controls, and eradication of the infection leads to a reduction in cell proliferation. Apoptosis and cell proliferation are also increased in precancerous lesions such as gastric atrophy, intestinal metaplasia, and dysplasia in the presence of H. pylori infection. However, H. pylori-induced apoptosis may no longer be cell cycle-dependent in these lesions because of the occurrence of alterations and mutations of apoptosis-regulating genes, resulting in a loss of balance between apoptosis and cell proliferation.

CONCLUSIONS

It is hypothesized that H. pylori-induced apoptosis may play a key role in gastric carcinogenesis by increasing cell proliferation and/or resulting in gastric atrophy.

VP22 enhanced intercellular trafficking of HSV thymidine kinase reduced the level of ganciclovir needed to cause suicide cell death

BACKGROUND

The inefficiency of herpes simplex virus thymidine kinase (TK) gene transfer and toxicity of ganciclovir (GCV) at high concentrations in vivo limits the use of this suicide gene therapy approach for the treatment of cancers in clinical settings. To overcome the problem, we have sought evidence of amplification of cytotoxicity by co-transfer of the TK gene fused with the gene encoding HSV-1 structural protein VP22 which has a remarkable ability for intercellular trafficking.

METHODS

The expression of the fusion proteins from the chimeric VP22-TK or VP22-EGFP genes was shown by Western blot and VP22 promoted TK or EGFP intercellular trafficking by an indirect immunofluorescent assay. The cytotoxicity was demonstrated by a colorimetric cell proliferation assay followed by an assessment of the bystander effect on admixtures of transfected with non-transfected naive cells.

RESULTS

Our results show the expression of the VP22 fusion proteins and their spread to varying numbers of bystander cells (up to 30, observed in viable cells with VP22-EGFP as well as after methanol fixation), confirming that VP22 assisted intercellular trafficking of the fusion proteins. This VP22 promoted TK spreading resulted in killing by 2.5 microg/ml GCV of virtually all cells in cultures that had been transfected at an efficiency of only 27.5%. In contrast, fewer than 80% of cells were killed when transfected with 'tk alone' at the same efficiency. The cell killing effect was exponentially dependent on GCV concentration in cells transfected with 'tk alone' at GCV concentrations between 0.25 and 0.5 microg/ml, but not those transfected with VP22-TK, probably due to the continuously variable, high sensitivity of about 50% of cells. Even at low concentration of GCV (0.2 microg/ml), the enhancement of cell killing by VP22 was four-fold higher in cells transfected with VP22-TK than in cells transfected with 'tk alone'.

CONCLUSIONS

VP22 enhanced intercellular trafficking of TK and amplified the TK/GCV killing effect, especially in the lower range of GCV concentrations. This offers a new strategy to enhance the effectiveness of suicide gene therapy for the treatment of cancers.

High preoparative levels of serum periostin are associated with poor prognosis in patients with hepatocellular carcinoma after hepatectomy

AIMS

Periostin (POSTN) is implicated in cancer development and progression. The aim of this study was to evaluate the diagnostic and prognostic significance of serum POSTN in patients with hepatocellular carcinoma (HCC) receiving curative surgery.

METHODS

Enzyme-linked immunosorbent assay was performed to determine serum POSTN levels in 69 healthy volunteers, 30 patients with hepatolithiasis, 27 patients with cirrhosis, and 56 HCC patients. The relationships between serum POSTN and clinicopathologic features were analyzed. Receiver operating characteristics analysis was used to calculate diagnostic accuracy of serum POSTN, serum alpha-fetoprotein (AFP), and their combination. The prognostic impact of serum POSTN on overall survival (OS) and relapse-free survival (RFS) was also investigated.

RESULTS

The median serum POSTN level was significantly (P < 0.05) increased in HCC patients, compared to healthy controls, patients with hepatolithiasis, and patients with liver cirrhosis. Elevated serum POSTN was only significantly associated with Edmondson grade (P = 0.007). The combination of serum POSTN and AFP had a markedly higher area under the curve (0.805 (95% confidence interval [CI]: 0.677-0.932)) than POSTN (0.582 (95% CI: 0.427-0.736)) or AFP (0.655 (95% CI: 0.504-0.806)) alone. Kaplan-Meier analysis indicated that elevated serum POSTN was associated with OS (P = 0.031) and RFS (P = 0.027). Moreover, multivariate analysis revealed elevated serum POSTN as an independent poor prognostic marker for OS and RFS.

CONCLUSIONS

Preoperative serum POSTN has limited diagnostic value in distinguishing HCC from non-malignant liver diseases, but serves as independent prognostic biomarker in HCC patients.

Distribution of distinct vacA, cagA and iceA alleles in Helicobacter pylori in Hong Kong

BACKGROUND

There is a substantial genetic heterogeneity among Helicobacter pylori strains, and certain genotypes have been suggested to be associated with the virulence of this pathogen. The aim of this study was to investigate the distribution of H. pylori vacA, cagA and iceA genotypes and their association with duodenal ulcer disease in Hong Kong.

MATERIALS AND METHODS

Gastric biopsies of 72 H. pylori infected patients were analyzed by specific polymerase chain reactions.

RESULTS

Of the 72 cases, 69 (95.8%) had vacA signal sequence s1c strains, and three (4.2%) had s1a strains. vacA middle region sequences, m1b and m2, were detected in 23 (31.9%) and 46 (63.9%), respectively. Six (8.3%) cases contained multiple vacA subtypes. vacA s2 allele was only observed in three (4.3%) cases, which were also infected with s1c subtype. cagA was present in 64 (88.9%) of 72 patients, and iceA1 subtype was detected in 46 (63.9%) cases. Neither cagA nor vacA and iceA were associated with duodenal ulcer disease.

CONCLUSION

The distribution of vacA, cagA and iceA alleles in H. pylori strains in Hong Kong is similar to that in east Asia. There is a difference in the distribution of genotypes between strains in Hong Kong and those in mainland China, although strains in the two regions exhibit a very close relation. The association of these virulence genes and duodenal ulcer disease needs reappraisal, particularly under geographic considerations.

Helicobacter pylori infection, reflux esophagitis, and atrophic gastritis: an unexplored triangle

OBJECTIVE

H. pylori causes chronic gastritis, which may progress to peptic ulcer, gastric atrophy, or gastric cancer. However, little is known about the role of H. pylori infection in reflux esophagitis and the relationship between reflux esophagitis and atrophic gastritis needs to be clarified. We sought to identify the possible interrelationships among Helicobacter pylori infection, reflux esophagitis, and atrophic gastritis, to signal areas in which researchers should consider focusing their attention.

METHODS

A broad-based Medline search was performed to identify all related publications addressing H. pylori infection, atrophic gastritis, gastroesophageal reflux disease (GERD), secretion of gastric acid, and gastric motility published between 1966 and July 1997.

RESULTS

Whereas some studies have shown no significant association between H. pylori infection and reflux esophagitis, others have observed that the prevalence of H. pylori infection was lower in patients with GERD, implying a protective role. Eradication of H. pylori leads to occurrence of reflux esophagitis in some cases, but the mechanisms inducing posteradication reflux esophagitis are unknown. H. pylori infection may lead to atrophic gastritis (and hence hypochlorhydia) through both bacterial and host factors, although gastric atrophy and subsequent intestinal metaplasia are hostile to H. pylori because of hypochlorhydria. Although it has been reported that long-term proton pump inhibitor therapy for refractory reflux esophagitis may induce or enhance the development of gastric atrophy in H. pylori-infected patients, this relationship has been disputed.

CONCLUSIONS

H. pylori infection may be negatively associated with reflux esophagitis, but this requires confirmation. Research then needs to focus on whether this is explained through motility- or acid-related mechanisms. The potential costs of maintenance antireflux therapy may need to be taken into account when evaluating the cost effectiveness of anti-H. pylori therapy.

Clinical and endoscopic characteristics of non-Helicobacter pylori, non-NSAID duodenal ulcers: a long-term prospective study

BACKGROUND

The proportion of duodenal ulcers not associated with Helicobacter pylori infection or the use of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing.

AIM

To identify the clinical and endoscopic characteristics of non-H. pylori, non-NSAID duodenal ulcers.

METHODS

Clinical and endoscopic data and H. pylori status were prospectively collected from consecutive patients who underwent upper endoscopy from 1997 to 1999. Patients with duodenal ulcers were identified, and those with non-H. pylori, non-NSAID duodenal ulcers were analysed further.

RESULTS

A total of 11 717 upper endoscopies were performed in 8344 patients. Of these, 1153 (14%) had duodenal ulcers. Of 599 patients with active ulcers and known H. pylori status, 104 (17%) had ulcers not associated with H. pylori or the use of NSAIDs, 393 (66%) had ulcers associated with H. pylori alone, 51 (8.5%) had ulcers associated with the use of NSAIDs alone and 51 (8.5%) had ulcers associated with both. Multivariate logistic regression analysis revealed that the presence of concomitant diseases (odds ratio=15.0; 95% confidence interval, 8.64-25.9; P < 0.001) and the absence of epigastric pain/discomfort (odds ratio=0.52; 95% confidence interval, 0.29-0.91; P=0.022) were independent predictors for non-H. pylori, non-NSAID duodenal ulcers.

CONCLUSIONS

Non-H. pylori, non-NSAID duodenal ulcers exhibit certain distinct clinical and endoscopic characteristics. The presence of concomitant diseases is an important predictive factor.

Reduction of peptic ulcer disease and Helicobacter pylori infection but increase of reflux esophagitis in Western Sydney between 1990 and 1998

We aimed to determine if changes in the patterns of upper gastrointestinal diseases at endoscopy have occurred over the past decade. Retrospectively, 917 consecutive patients were selected based on upper endoscopy between June 1 and August 31, in 1990 (n = 217), 1994 (n = 270), and 1998 (n = 430). Demographic, clinical, endoscopic, and histological information were extracted from the medical records on a standardized case record form. Over the eight-year period, follow-up of peptic ulcer (15%, 5%, and 5%, respectively, in 1990, 1994, and 1998, df = 2, P < 0.001), bleeding (22%, 14%, and 13%, P = 0.008), and nausea/vomiting (15%, 16%, and 10%, df = 2, P = 0.003) had become less frequent, but reflux (21%, 19%, and 34%, df = 2, P < 0.001) and dyspepsia (24%, 43%, and 32%, df = 2, P < 0.001) more frequent indications for upper endoscopy. The prevalence of peptic ulcer disease decreased (22%, 15%, and 13%, df = 2, P = 0.025), but the prevalence of reflux esophagitis increased significantly (29%, 30%, and 39%, df = 2, P = 0.010). The prevalence of both the use of nonsteroidal antiinflammatory drugs (NSAIDs) (18%, 20%, and 11%, respectively, in 1990, 1994, and 1998, df = 2, P = 0.004) and H. pylori infection (39% in 1994 and 30% in 1998, df = 1, P = 0.032) decreased. Overall, NSAID use was independently associated with gastric ulcers (OR = 2.39, 95% CI 1.21-4.73, chi2 = 6.31, df = 1, P = 0.012), but not esophagitis. H. pylori infection was independently associated with duodenal ulcers (OR = 4.74, 95% CI 2.30-9.77, chi2 = 17.8, df = 1, P < 0.001), histologically chronic (OR = 166.8, 95% CI 76.1-365.4, chi2 = 313.0, df = 1, P < 0.001) and active (OR = 30.1, 95% CI 17.0-53.5, chi2 = 189.7, df = 1, P < 0.001) gastritis and lymphoid aggregates (OR = 5.49, 95% CI 3.02-9.97, chi2 = 36.3, df = 1, P < 0.001). In conclusion, the prevalence of peptic ulcer disease appears to have been decreasing, whereas reflux esophagitis has been increasing over the past decade in Western Sydney. The decreased use of NSAIDs and decline of H. pylori infection have likely both contributed to the reduction of peptic ulcer disease, but the increase in reflux esophagitis remains to be fully explained.

Novel bovine lentiviral vectors based on Jembrana disease virus

BACKGROUND

Safety is a concern that must be addressed prior to any clinical use of human immunodeficiency virus (HIV)-based lentiviral vectors in human patients. Unfortunately, efforts to examine the biosafety of the vectors in preclinical animal models are hampered due to the lack of animal models for HIV infection. We have developed new lentiviral vectors based on the recently characterised Jembrana Disease Virus (JDV), which infects a specific species of cattle naturally in Bali, Indonesia.

METHODS

Sequences from the JDV genome were amplified by splicing overlap extension polymerase chain reaction (PCR) for the construction of transfer vectors as well as a packaging construct. Co-transfection of these two plasmids into 293T cells with a third encoding a G glycoprotein of vesicular stomatitis virus produced pseudotyped, disabled, replication defective JDV vector particles. Viral titre was obtained by transducing the cells with the supernatant harvested from transfectants and determining the number of cells expressing the transgene. PCR and Southern blotting were used to detect the presence of potential replication-competent viruses as well as transgene integration.

RESULTS

Bicistronic JDV vectors encoding the green fluorescent protein (GFP) and the neomycin phosphotransferase were harvested with a titre range of 0.4-1.2 x 10(6) colony forming units/ml from vector-producing cells and were further concentrated by ultracentrifugation to the high titre of approximately 10(7) CFU/ml. Vectors encoding GFP were shown to transduce and integrate efficiently into the chromosomes of a range of primary and transformed cells of different origins in different differentiation status, including growth-arrested cells, with an efficiency of 25-75%. Exhaustive testing with a marker gene transfer assay in combination with a reverse transcriptase assay and PCR amplification of samples of serially passaged, transduced cells showed that no detectable amount of replication competent lentivirus (RCL) was produced.

CONCLUSIONS

We showed the feasibility of the development of gene transfer vectors based on a non-primate bovine lentivirus, which will provide the opportunity for examination of the efficacy and biosafety of lentiviral vector-mediated gene transfer in vivo in animal models. JDV-based vectors may be applicable and more readily acceptable than those from HIV for human gene therapy.

Demographic and endoscopic characteristics of patients with Helicobacter pylori positive and negative peptic ulcer disease

OBJECTIVE

To identify demographic and endoscopic characteristics of patients with Helicobacter pylori positive and negative chronic peptic ulcer disease.

DESIGN

Cross-sectional study of peptic ulcer disease in prospectively recruited PATIENTS undergoing gastroscopy.

PATIENTS

277 consecutive patients referred for gastroscopy in 1996-1998.

MAIN OUTCOME MEASURES

Rapid urease test, culture and histological examination for H. pylori infection; anti-H. pylori IgG antibodies in serum; demographic data, intake of non-steroidal anti-inflammatory drugs (NSAIDs) in the preceding 3 months, and size, number and location of ulcers.

RESULTS

54 patients (19%) had evidence of peptic ulcer disease (34 gastric ulcer, 14 duodenal ulcer and 6 both gastric and duodenal ulcer); 45 had active chronic peptic ulcer disease and were analysed in detail. H. pylori was present in 25 (56%) of these patients; 10 (22%) had used NSAIDs and 7 of the NSAID group also had H. pylori infection. Of the patients with gastric ulcers, those with non-H. pylori, non-NSAID ulcers were significantly younger than both those with H. pylori-associated ulcers (mean age, 48 v. 65 years, P = 0.02) and those with NSAID-associated ulcers (mean age, 48 v 68 years, P = 0.02). The average size and number of gastric ulcers did not differ between patients with and without H. pylori infection. Of patients with duodenal ulcers, those with H. pylori infection had significantly fewer ulcers (1.1 v. 1.8, P = 0.04), although ulcer size was similar in the infected and uninfected groups.

CONCLUSIONS

Gastric ulcers may now be more common than duodenal ulcers. Gastric ulcers associated with H. pylori infection and/or NSAID use occurred mostly in older people, while non-H. pylori, non-NSAID gastric ulcers were more common in younger patients. In the duodenum, single ulcers were associated with H. pylori infection, and multiple ulcers were more frequent in the non-H. pylori, non-NSAID group.

High sensitivity and specificity of a laboratory-based serological test, pylori DTect ELISA, for detection of Helicobacter pylori infection

A number of commercial ELISA kits are now available for detection of Helicobacter pylori infection. Generally, whereas the manufacturers have claimed high sensitivity and specificity, independent studies have often failed to confirm the results. The aim of this study was to independently evaluate the pylori DTect ELISA, a commercial kit for detection of H. pylori infection, in Australian patients with dyspepsia and reflux symptoms. Two hundred and nine consecutive patients (102 males and 107 females, mean age 52.8 years) who were referred for endoscopy due to upper gastrointestinal symptoms, but had not received anti-H. pylori therapy were enrolled. A 10 mL blood sample was obtained from each subject and used to evaluate the kit. The absorbance index (AI) was calculated from the mean of two readings of optical density (OD) of each serum sample. Eight biopsies from the gastric antrum (x3), body (x2), fundus (x2), and incisura (x1) were obtained from each patient for CLO-testing (x1), culture (x3), and histological examination (x4) for H. pylori. Overall, 84 (40.2%) patients were infected with H. pylori as determined by the biopsy-based "gold standard." The AIs ranged from 0 to 1.86; 0.12 to 1.86 in H. pylori positive patients and 0 to 1.49 in negative patients. The pylori DTect ELISA obtained an accuracy of 94 to 95% under AI ranges between 0.20 to 0.40, with the highest accuracy being 95% under AIs of 0.25 and 0.35. An AI of 0.25 was recommended as the best cut-off AI, with a sensitivity of 96.4%, specificity of 93.6%, positive predictive value of 91% and negative predictive value of 97.5%. It is concluded that the pylori DTect ELISA is accurate for detecting H. pylori infection in patients with dyspepsia and reflux symptoms in Australia, when an AI of 0.25 is taken as the cut-off value.

Can helicobacter pylori serology still be applied as a surrogate marker to identify peptic ulcer disease in dyspepsia?

BACKGROUND

Helicobacter pylori infection and associated peptic ulcer disease (PUD) has become less common in some countries.

AIM

To determine if H. pylori serology alone or combined with a history of ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) and an age threshold can be used as an indirect ulcer test.

METHODS

Two hundred and fifty-two consecutive Australian patients (121 males, mean age 52 years) referred for endoscopy were enrolled. Blood was tested by a validated ELISA. At endoscopy, eight biopsies were taken for CLO-testing, culture and histology. NSAID use over the prior 3 months was recorded.

RESULTS

One hundred and six (42%) patients were seropositive for H. pylori, 48 (19%) patients had PUD and 30 (12%) used NSAIDs. Serology alone had a sensitivity of 52% and a specificity of 60% for identifying PUD; the sensitivity and specificity were 60% and 55%, respectively, when combined with a history of NSAID use. Serology, regardless of NSAID use, would have saved 23% in endoscopy workload but would have missed 17% of PUD cases if an age threshold of < 45 years was chosen for omitting endoscopy.

CONCLUSIONS

Serology was a poor ulcer test despite an excellent performance for detecting H. pylori. A strategy combining serology and an age threshold with a history of NSAID use to reduce endoscopy workloads may not always be appropriate.

An evaluation of whole blood testing for Helicobacter pylori in general practice

BACKGROUND

Rapid whole blood tests for Helicobacter pylori infection were developed to assist in the management of patients with dyspepsia in general practice. However, they have not been extensively tested in this setting.

AIM

To investigate the test characteristics of the BM-Test (Helisal Quick Test) when used in general practice.

METHOD

One hundred and ten dyspeptic patients attending local general practitioners were recruited into the study. The BM-Test was administered by the general practitioner at the screening visit according to standard instructions supplied with the test kit. The patient was then referred to Nepean or Mornington Peninsula Hospitals for further assessment. including a 14C-urea breath test. The test kit was forwarded to the appropriate hospital centre for an independent, blinded reading. The sensitivity and specificity of the BM-Test were evaluated against the results of the 14C-UBT.

RESULTS

Based on general practitioner readings, the BM-Test had a sensitivity of 59.3% and a specificity of 90.2%. The positive and negative predictive values were 87.5% and 65.7%, respectively. When based on independent readings, sensitivity rose to 71.2% and specificity fell to 88.2%. The BM-Test was more sensitive for older patients than for younger patients when based on both the general practitioner and independent readings.

CONCLUSION

The BM-Test performs below the generally recommended sensitivity and specificity of 90% required for clinical practice.

Metronidazole- and clarithromycin-resistant Helicobacter pylori in dyspeptic patients in western Sydney as determined by testing multiple isolates from different gastric sites

It is unknown whether antibiotic susceptibility testing of antral isolates alone is representative of Helicobacter pylori susceptibility. We aimed to determine: (i) the prevalence of metronidazole- and clarithromycin-resistant strains in infected dyspeptic patients; and (ii) whether there is consistency in the susceptibility to metronidazole and clarithromycin among isolates cultured from different gastric sites. Antral, body and fundus biopsies were taken from 242 consecutive patients and cultured on blood agar under micro-aerophilic conditions for 5-7 days. Isolates from 66 patients (13 had one, 15 had two and 38 had three isolates) were tested for susceptibility to metronidazole and clarithromycin using previously validated disc diffusion tests. Of the 66 patients, 42 (64%) had strains resistant to metronidazole while four (6.1%) had clarithromycin-resistant strains. The prevalence of metronidazole resistance was not significantly different between men and women (65% vs 60%) or across different age groups. In five (9.4%) of the 53 patients with multiple isolates, discrepant results for metronidazole susceptibility were observed: susceptible antral and body isolates but resistant fundus isolates in two cases and susceptible antral isolates but resistant body and fundus isolates in the others. Clarithromycin susceptibilities were consistent among the isolates cultured from different gastric sites in all patients. It is concluded that metronidazole-resistant strains of H. pylori are common while clarithromycin-resistant strains are rare. Metronidazole susceptibility testing of antral isolates does not appear to be representative of isolates from the body and fundus in a subset of patients.

Twenty-minute 50 mg 13C-urea breath test without test meal for the diagnosis of Helicobacter pylori infection in Chinese

BACKGROUND

We have previously shown that the 75 mg 13C-urea breath test without citrate test meal is highly accurate for the diagnosis of Helicobacter pylori infection in Chinese subjects. A lower dose 50 mg 13C-urea breath test protocol with a sampling time at 20 min has not been validated previously.

AIM

To investigate the accuracy of a 20-min 50 mg 13C-urea breath test protocol in Chinese subjects.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. 13C-urea breath test was performed using (a) 75 mg and 50 mg of 13C-urea on two separate days without a test meal, and (b) 50 mg of 13C-urea with 2.4 g citrate as test meal, and compared with the gold standard [rapid urease test (CLO test) and histology]. Baseline, 20-min and 30-min breath samples were collected in all cases.

RESULTS

Two hundred and six patients were tested. The accuracy of the 50 mg 13C-urea breath test (no citrate) at 20 min and 30 min was 98%, comparable to that of the 50 mg 13C-urea breath test with citrate (99.1%) and the 75 mg 13C-urea breath test without citrate (100%).

CONCLUSIONS

A 20-min 50 mg 13C-urea breath test without citrate produced highly accurate results for the diagnosis of Helicobacter pylori infection and is more economical and convenient for the Chinese population.

Helicobacter pylori eradication in patients with non-ulcer dyspepsia

Epidemiological and pathophysiological studies, as well as clinical trials, attempting to identify a relationship between Helicobacter pylori infection and non-ulcer dyspepsia (NUD), or a subset of NUD, have produced inconsistent and confusing results. While it is possible that H. pylori eradication may be beneficial for symptom relief in a small proportion of patients, routine H. pylori testing and treatment in documented NUD is not currently widely accepted. Despite the lack of convincing evidence, the European Helicobacter pylori Study Group, an Asian Pacific Consensus Meeting, the American Digestive Health Foundation and the American Gastroenterology Association have all recommended considering H. pylori eradication in patients with NUD on a patient-by-patient basis. Recently, large prospective, randomised, double-blind, controlled clinical trials applying highly effective antimicrobial therapy have been conducted with 12 months follow-up. Although these well-designed studies have reached differing conclusions, the results have been largely negative. H. pylori eradication therapy in NUD will fail to relieve symptoms in most patients in the long term.

Helicobacter pylori infection and non-ulcer dyspepsia

Epidemiological, pathophysiological and therapeutic studies have been carried out in order to try and establish whether an association between H. pylori infection and non-ulcer dyspepsia exists. A meta-analysis of pooled data showed that the prevalence of H. pylori infection in dyspepsia was higher than in controls (odds ratio 2.3), but this may be explained by selection bias. No convincing symptom profiles have been found to be associated with the infection, and there have been no consistent observations regarding the effects of the infection on gastroduodenal motility or sensation. Clinical trials in adults have been equivocal. Although a recent meta-analysis identified an overall benefit of H. pylori therapy, only selected trials could be included. Some studies have suggested that significant symptom improvement requires up to 12 months follow-up to be documentable. Little relevant paediatric clinical trial data are available. While it is possible that H. pylori may be responsible for symptoms in a small proportion of patients with non-ulcer dyspepsia and in some of these cases anti-H. pylori therapy may be beneficial, this remains to be established.

Sigma-nucleus potential in A=28

We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.

Association of Helicobacter pylori infection with gastric carcinoma: a meta-analysis

OBJECTIVE

As conflicting studies have recently been published, we aimed to determine if Helicobacter pylori (H. pylori) infection is associated with gastric adenocarcinoma.

METHODS

This was a meta-analysis of observational epidemiological studies.

RESULTS

A total of 42 studies met the selection criteria and were categorized by the type of study design: eight cohort and 34 case-control studies. The pooled odds ratio for H. pylori in relation to gastric carcinoma was 2.04 (95% CI: 1.69-2.45). Both patient age (OR 0.77, 95% CI: 0.68-0.89) and intestinal type cancers (OR 1.14, 95% CI: 1.05-1.25) were independent effect modifiers. Analysis of other effect modifiers showed no relationship with female gender (OR 0.76, 95% CI: 0.64-0.89), stage of cancer (advanced %) (OR 1.12, 95% CI: 0.88-1.43), anatomical location (cardia %) (OR 1.54, 95% CI: 0.32-7.39) or cohort (nested case-control) studies (OR 1.72, 95% CI: 0.32-9.17). There was significant heterogeneity among the studies (tau2 = 149; p < 0.001). The quality of the studies varied considerably, with the majority of excellent studies producing positive results and the very poor to moderate studies producing mixed results.

CONCLUSIONS

H. pylori infection is associated with a 2-fold increased risk of developing gastric adenocarcinoma.

Helicobacter pylori infection--current treatment practice

Helicobacter pylori infection, which is present in 30 - 60% of the population in developed countries and in more than 60% in developing countries, is established to be a major cause of gastritis, peptic ulcer disease and gastric cancer. Eradication therapy has been incorporated into clinical practice over the past 15 years. Treatment regimens include a 2 week bismuth-based triple therapy (a bismuth compound plus metronidazole, tetracycline or amoxycillin), a 1 week proton-pump inhibitor (PPI)-based triple therapy and a 1 week ranitidine bismuth citrate (RBC)-based triple therapy (a PPI or RBC plus any two of the three antibiotics, metronidazole, amoxycillin and clarithromycin). These regimens achieve eradication rates of >> 80%. H. pylori resistance to metronidazole and clarithromycin decreases the clinical efficacy of most regimens, despite the high eradication rates for resistant strains achieved by the RBC-triple therapy in some recent trials. The dose of antibiotics (especially clarithromycin) and the duration of treatment may also influence the eradication rate. Doctors' beliefs impact on clinical practice and, thus, influence the clinical application of eradication therapy. Whereas peptic ulcer disease and primary gastric low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma) have become established as definite indications for eradication therapy, there remain controversies surrounding non-ulcer dyspepsia, gastro-oesophageal reflux disease, atrophic gastritis, intestinal metaplasia, use of non-steroidal anti-inflammatory drugs (NSAIDs) and H. pylori-related extradigestive diseases.

Measurement of the B(e2) of (7)(lambda)Li and shrinkage of the hypernuclear size

We report on the first measurement of a hypernuclear gamma-transition probability. gamma rays emitted in the E2(5/2(+)-->1/2(+)) transition of (7)(Lambda)Li were detected by a large-acceptance germanium detector array (Hyperball), and the lifetime of the parent state ( 5/2(+)) was determined by the Doppler shift attenuation method. The obtained result, 5.8(+0.9)(-0.7)+/-0.7 ps, was then converted into the reduced transition probability [ B(E2)] to be B(E2;5/2(+)-->1/2(+)) = 3.6+/-0.5(+0.5)(-0.4) e(2) fm(4). Compared with the B(E2) of the corresponding E2(3(+)-->1(+)) transition in the 6Li nucleus, our result gives evidence that the size of the 6Li core in (7)(Lambda)Li is smaller than the 6Li nucleus in the free space.