S. K. Lam

Prevalence, clinical spectrum and health care utilization of gastro-oesophageal reflux disease in a Chinese population: a population-based study

Background : Population‐based data on gastro‐oesophageal reflux disease in Chinese are lacking. The prevalence, clinical spectrum and health care‐seeking behaviour of subjects with gastro‐oesophageal reflux disease were studied.

Promoter methylation of E-cadherin gene in gastric mucosa associated with Helicobacter pylori infection and in gastric cancer.

Background:E-cadherin is an adhesion molecule involved in tumour invasion/metastasis. Silencing of E-cadherin by promoter CpG methylation has been shown in both familial and sporadic gastric cancers. Helicobacter pylori is a class I carcinogen in gastric cancer. Aims: This study was undertaken to investigate the association between methylation of E-cadherin and H pylori in gastric mucosa from dyspeptic patients, and in intestinal metaplasia and primary and metastatic adenocarcinoma from surgical specimens of patients with gastric cancer. Methods:E-cadherin methylation was studied using methylation specific polymerase chain reaction in microdissected tissue from biopsies or surgical resection specimens. E-cadherin expression was studied by immunohistochemistry. Results:E-cadherin methylation was present in 31% (11/35) of gastric mucosae from dyspeptic patients, and was associated with H pylori infection (p=0.002), but was independent of the age of the patient or presence or absence of gastritis. E-cadherin methylation was present in 0% (0/8) of normal mucosa, 57% (12/21) of intestinal metaplasias, and 58% (15/26) of primary and 65% (21/32) of metastatic cancers. E-cadherin methylation status was concordant in 92% (11/12) of intestinal metaplasias and primary cancers, and in 85% (17/20) of primary and metastatic cancers from the same resected specimen. E-cadherin methylation in gastric cancer was associated with depth of tumour invasion (p=0.02) and regional nodal metastasis (p=0.05). Conclusion:E-cadherin methylation is an early event in gastric carcinogenesis, and is initiated by H pylori infection.

Anxiety but not depression determines health care-seeking behaviour in Chinese patients with dyspepsia and irritable bowel syndrome: a population-based study

Aims : To study the prevalence of dyspepsia and irritable bowel syndrome and the effects of co‐existing anxiety and depression on health care utilization by a population survey in Chinese.

Lectins: production and practical applications

Lectins are proteins found in a diversity of organisms. They possess the ability to agglutinate erythrocytes with known carbohydrate specificity since they have at least one non-catalytic domain that binds reversibly to specific monosaccharides or oligosaccharides. This articles aims to review the production and practical applications of lectins. Lectins are isolated from their natural sources by chromatographic procedures or produced by recombinant DNA technology. The yields of animal lectins are usually low compared with the yields of plant lectins such as legume lectins. Lectins manifest a diversity of activities including antitumor, immunomodulatory, antifungal, HIV-1 reverse transcriptase inhibitory, and anti-insect activities, which may find practical applications. A small number of lectins demonstrate antibacterial and anti-nematode activities.

Eradication of Helicobacter pylori infection reverses E-cadherin promoter hypermethylation

Background: E-cadherin methylation is important in gastric carcinogenesis. Reversing hypermethylation may halt the carcinogenic process. We have previously reported that Helicobacter pylori infection is associated with E-cadherin methylation in chronic gastritis patients. Aim: To examine if eradication of H pylori could reverse E-cadherin methylation. Methods: Patients with dyspepsia and positive for H pylori infection, with a mucosal biopsy showing chronic active gastritis, were randomised to receive H pylori eradication therapy (group 1, n = 41) or no treatment (group 2, n = 40), and were followed up prospectively. Gastric mucosae were taken for methylation assay at week 0 (before treatment) and week 6 (after treatment). Archived specimens of intestinal metaplasia with H pylori infection (n = 22) and without (n = 19) were retrieved for methylation analysis. Methylation was assessed using methylation specific polymerase chain reaction and sequencing. Results: Methylation at E-cadherin was detected in 46% (19/41) and 17% (7/41) of patients at weeks 0 and 6, respectively, in group 1 (p = 0.004); 78.9% (15/19) of specimens were unmethylated after eradication of H pylori. Mucosal biopsy showed chronic inactive gastritis in 35 patients, intestinal metaplasia in one, and normal mucosa in five at week 6. Methylation was detected in 47.5% (19/40) and 52.5% (21/40) of patients at weeks 0 and 6, respectively, in group 2 (P = 0.5). Gastric mucosal biopsy showed persistent chronic active gastritis in all cases. Methylation frequency did not differ in H pylori positive or negative intestinal metaplastic specimens (72.7% v 63%; p = 0.5). Conclusion:H pylori eradication therapy could reverse methylation in patients with chronic gastritis. This demonstrates an environmental effect on methylation.

Randomized controlled study of rabeprazole, levofloxacin and rifabutin triple therapy vs. quadruple therapy as second‐line treatment for Helicobacter pylori infection

Aim : To test the efficacy of rabeprazole, levofloxacin and rifabutin triple therapy vs. quadruple therapy for the second‐line treatment of Helicobacter pylori infection.

Double blind, randomised, placebo controlled study of four weeks of lansoprazole for the treatment of functional dyspepsia in Chinese patients

Background: The use of proton pump inhibitors for the treatment of functional dyspepsia is controversial and the role of Helicobacter pylori infection in functional dyspepsia is uncertain. Aim: To evaluate the efficacy of different doses of lansoprazole for the treatment of functional dyspepsia in Chinese patients. Method: Patients with a clinical diagnosis of functional dyspepsia according to the Rome II criteria and normal upper gastrointestinal endoscopy were recruited and randomised to receive: (1) lansoprazole 30 mg,(2) lansoprazole 15 mg, or (3) placebo, all given daily for four weeks. Dyspepsia symptom scores and quality of life (SF-36 score) were evaluated before and four weeks after treatment. Results: A total of 453 patients were randomised. There was no difference in the proportion of patients with complete symptom relief in the lansoprazole 30 mg (23%) and lansoprazole 15 mg (23%) groups compared with the placebo group (30%). The proportion of H pylori positive patients with a complete response was similar with lansoprazole 30 mg (34%) and lansoprazole 15 mg (20%) versus placebo (22%). All symptom subgroups (ulcer-like, dysmotility-like, reflux-like, and unspecified dyspepsia) had similar proportions of patients with complete symptom relief after treatment. Conclusion: Proton pump inhibitor treatment is not superior to placebo for the management of functional dyspepsia in Chinese patients.

Long-term prospective follow-up of endoscopic oesophagitis in southern Chinese - prevalence and spectrum of the disease

Aims : To study the prevalence, clinical characteristics and long‐term outcome of oesophagitis in Chinese patients.

Soluble E-cadherin is a valid prognostic marker in gastric carcinoma

BACKGROUND Gastric cancer remains a major cause of cancer mortality globally but no good prognostic tumour marker is available. Soluble fragment of E-cadherin protein has been reported to increase in the sera of patients with cancer and recently was found to be elevated in 67% of patients with gastric cancer. AIMS To investigate if serum soluble E-cadherin is a valid prognostic marker in gastric cancer. METHODS Concentrations of soluble E-cadherin from 116 patients with histologically confirmed gastric adenocarinoma and 40 healthy subjects were measured using an immunoenzymometric method with a commercially available sandwich ELISA kit based on monoclonal antibodies. RESULTS The logarithm of the means of soluble E-cadherin concentration was significantly higher in patients with gastric cancers (mean 3.85 (SD 0.28)) than in healthy subjects (3.71 (0.18)) (p=0.001), and in palliative/conservatively treated cancers (3.91 (0.35)) than in operable cancers (3.78 (0.19)) (p=0.015). The logarithm of the concentrations correlated with tumour size (p=0.032) and carcinoembryonic antigen concentrations (p=0.001). The cut off value calculated from discriminant analysis on operability and inoperability/palliative treatment was 7025 ng/ml. Soluble E-cadherin concentrations higher than this cut off value predicted tumour (T4) depth invasion (p=0.020, confidence interval (CI) 1.008–1.668) and palliative/conservative treatment (p=0.023, CI 1.038–2.514). In contrast, the relative risks for lymph node (N2) metastasis, distant metastasis, and stage III/IV disease were 1.41, 1.33, and 1.55 respectively, despite not reaching statistical significance. CONCLUSION Serum soluble E-cadherin is a potential valid prognostic marker for gastric cancer. A high concentration predicts palliative/conservative treatment and T4 invasion.

A sensitive guaiac faecal occult blood test is less useful than an immunochemical test for colorectal cancer screening in a Chinese population

Background : Colorectal cancer screening by guaiac faecal occult blood test has been shown to reduce the incidence and mortality of colorectal cancer in Western populations. The optimal faecal occult blood test, whether guaiac or immunochemical, for colorectal cancer screening in the Chinese population remains to be defined.