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Biomedical subjects

C K Ching

Publications and source records attributed to C K Ching.

At least 37 records · Page 2Linked to original sources
PubMed1998

The combination of omeprazole, amoxycillin, and clarithromycin eradicates Helicobacter pylori in 95% of patients---7 days of therapy is as good as 10 days.

More than half of the known Helicobacter pylori strains are resistant to metronidazole, according to previous Hong Kong studies. The response rates to treatment regimens that comprise metronidazole as one of the antimicrobial agents have usually been disappointing in cases involving metronidazole-resistant strains. The objective of this open cohort evaluation was to assess the efficacy of an alternative regimen that combines omeprazole with amoxycillin and clarithromycin in Helicobacter pylor-positive ulcer and non-ulcer patients in Hong Kong. Furthermore, we aimed to investigate if 7 days were as good as 10 days of therapy. We studied 186 Helicobacter pylor-positive subjects; 149 subjects received 7 days of combination therapy and 37 subjects received 10 days. Our results showed that the overall Helicobacter pylori eradication efficiency was identical (94.6%) for both treatments. The incidences of adverse effects were also very similar (16.8% versus 16.2%) and both treatments were well tolerated. Thus, we propose that omeprazole in combination with amoxycillin and clarithromycin should be considered as one of the first-line therapies for patients with Helicobacter pylor infection in Hong Kong.

Journal Article↗
PubMed1997

Lamivudine is effective in suppressing hepatitis B virus DNA in Chinese hepatitis B surface antigen carriers: a placebo-controlled trial.

Lamivudine is a novel 2',3'-dideoxy cytosine analogue that has potent inhibitory effects on hepatitis B virus replication in vitro and in vivo. We performed a single-blind, placebo-controlled study to assess its effectiveness and safety in Chinese hepatitis B surface antigen (HBsAg) carriers. Forty-two Chinese HBsAg carriers were randomized to receive placebo (6 patients) or lamivudine orally in dosages of 25 mg, 100 mg, or 300 mg daily (12 patients for each dosage). The drug was given for 4 weeks. The patients were closely monitored clinically, biochemically, and serologically up to 4 weeks after drug treatment. All 36 patients receiving lamivudine had a decrease in hepatitis B virus (HBV) DNA values of >90% (P < .001 compared with placebo). Although 25 mg of lamivudine was slightly less effective than 100 mg (P = .011) and 300 mg (P = .005), it still induced 94% suppression of HBV DNA after the fourth week of therapy. HBV DNA values returned to pretreatment levels within 4 weeks of cessation of therapy. There was no change in the hepatitis B e antigen status or in aminotransferase levels. No serious adverse events were observed. In conclusion, a 4-week course of lamivudine was safe and effective in suppression of HBV DNA in Chinese HBsAg carriers. The suppression was >90% but reversible. Studies with long-term lamivudine administration should be performed to determine if prolonged suppression of HBV DNA can be achieved.

Adolescent↗
PubMed1997

A retrospective and prospective study on the safety of discharging selected patients with duodenal ulcer bleeding on the same day as endoscopy.

BACKGROUND: Low risk of rebleeding has been observed in patients with gastrointestinal bleeding due to peptic ulcer without high-risk stigmata of recent hemorrhage. We aimed to evaluate the safety and acceptability of an aggressive early discharge policy in those patients admitted with upper gastrointestinal bleeding due to duodenal ulcers without high-risk stigmata of recent hemorrhage. METHOD: Retrospective analysis was carried out in bleeding ulcer patients less than 60 years of age with stable vital signs and no stigmata or only flat spots on endoscopy. A prospective study was then performed that included only duodenal ulcer patients less than 60 years of age with stable vital signs, no concomitant serious medical illness, and no stigmata of recent hemorrhage. These patients were discharged on the same day that endoscopy was performed. RESULTS: During a period of 18 months, 72 patients satisfied the criteria in the retrospective study. The mean hospital stay was 1.4 days (range, 1 to 5). There were no episodes of rebleeding nor significant drops in hemoglobin level 2 weeks after discharge (10.8 gm/dL +/- 1.4 vs 11.0 gm/dL +/- 1.5). Seventy-five patients were recruited into the prospective study. None of them had rebleeding nor significant drops in hemoglobin 1 week after discharge (12.1 gm/dL +/- 1.8 vs 11.7 gm/dL +/- 2.5). CONCLUSION: We conclude that patients with gastrointestinal bleeding who have clean-based duodenal ulcers and are stable on admission can be safely discharged on the same day as endoscopy.

Adolescent↗
PubMed1997

The vascular and glandular organoprotective properties of metronidazole in the rodent stomach.

BACKGROUND: The gastroprotective action of metronidazole, an antimicrobial used in the therapy against Helicobacter pylori infection, is unclear. Thus, the aim of the present investigation was to study the organoprotective action and antiulcer mechanisms of this drug in rodents. METHODS AND RESULTS: Metronidazole (10 mg/kg), given either per os or intraperitoneally, 30 min beforehand, reduced ethanol (40%, 10 mL/kg, p.o.)-induced gastric mucosal damage in male rats. Likewise, oral administration of metronidazole dose-dependently attenuated the indomethacin (30 mg/kg, p.o.)-induced gastric lesion formation and the concurrent depletion of mucosal mucus. However, metronidazole did not affect the basal mucosal prostaglandin E2 content. In an ex vivo gastric chamber preparation, 40% ethanol incubation markedly lowered transmucosal potential difference and increased mucosal vascular permeability in rat stomachs. Incubation with all doses of metronidazole did not modulate gastric mucosal blood flow nor transmucosal potential difference, either before or after ethanol treatment. Nevertheless, the increase in vascular permeability by 40% ethanol was significantly alleviated by either p.o. or i.p. metronidazole pretreatment. In addition, exposure of the isolated rabbit gastric gland preparation to metronidazole (10(-5) and 10(-4) M) significantly attenuated the damaging action of 10% ethanol. CONCLUSION: It is concluded that metronidazole possesses a direct vascular and glandular organoprotective property in the rodent stomach. However, the anti-ulcer action does not appear to involve prostaglandins nor act through the improvement of gastric mucosal blood flow. Preservation of intramucosal mucus may partly contribute to the prevention of indomethacin-induced ulceration in rats.

Animals↗
PubMed1997

Does treatment of Helicobacter pylori with antibiotics alone heal duodenal ulcer? A randomised double blind placebo controlled study.

BACKGROUND: Treatment of Helicobacter pylori infection prevents duodenal ulcer relapse. It has not been established if treatment of the infection heals duodenal ulcer. AIM: To test the hypothesis that treatment of the infection was associated with healing of duodenal ulcer. METHODS: A randomised, double blind placebo controlled trial was performed to study the efficacy of an antibiotic only regimen consisting of 300 mg metronidazole, 500 mg amoxycillin, and 250 mg clarithromycin, each given four times daily for two weeks, in the healing of duodenal ulcer as assessed by endoscopy. Symptoms were controlled with acetaminophen and antacids. RESULTS: Of 100 consecutive patients with endoscopically established duodenal ulcer, 97 with positive rapid urease test on antral biopsy specimens were admitted into the study and 81 completed the trial. Of these, 40 were randomised to receive antibiotics and 41 to receive placebo. Treatment with antibiotics resulted in 92.5% (95% confidence interval (95% CI) 84.3-100) healing at four weeks and 100% at eight and 12 weeks; the corresponding healing rates for placebo treatment were respectively, 36.6%, 61%, and 63.4% (95% CIs 21.8-51.3, 46.0-75.9, and 48.7-78.2 respectively). The differences between the two treatment groups were significant at p < 0.001 at each time point and by life table analysis. Clearance of H pylori as assessed by urease test on antral biopsy specimens at four weeks and eradication of the organism as determined by 13C-urea breath test at eight weeks were achieved in 85% and 62.5% of patients respectively. Duodenal ulcer healed at four weeks in 87.2% and 86.2% (95% CIs 76.7-97.7 and 73.7-98.8) of patients in whom H pylori clearance or eradication, was achieved, versus 42.9% and 51.9% (95% CIs 27.9-57.8 and 38.3-65.5; p < 0.001 and < 0.003 respectively) in whom these processes failed. Stepwise discriminant analysis on 32 clinical, personal, and endoscopic characteristics as well as H pylori clearance and eradication identified H pylori clearance as the most discriminative variable for the healing of duodenal ulcer at four weeks, followed by ulcer depth and eradication of the organism. CONCLUSIONS: Treatment with an antibiotic only regimen was effective for the healing of duodenal ulcer, and clearance as well as eradication of H pylori contributed significantly to the healing. The results constituted the strongest evidence to date that H pylori infection was aetiologically related to duodenal ulceration, and support the concept of treating duodenal ulcer associated with H pylori as an infection and relieving its symptoms with acid reducing agents such as antacids.

Adult↗
PubMed1996

Prevalence of metronidazole resistant Helicobacter pylori strains among Chinese peptic ulcer disease patients and normal controls in Hong Kong.

BACKGROUND: A study was conducted to evaluate the prevalence of metronidazole resistant Helicobacter pylori strains among the Chinese in Hong Kong. The efficacy of the triple therapy that contains metronidazole as one of the anti-microbial agents in eradication of the metronidazole susceptible and the metronidazole resistant strains was also assessed. METHODS: Culture for H pylori was attempted from antral biopsy specimens of 70 peptic ulcer and 51 control subjects. Successfully cultured H pylori strains were tested for metronidazole susceptibility. Twenty six peptic ulcer disease subjects who had received a course of triple therapy were also reassessed four to six weeks later for successful eradication of H pylori infection. RESULTS AND CONCLUSIONS: H pylori was successfully cultured from antral biopsy specimens in 69 of 80 (86%) of the infected subjects. The overall metronidazole resistance rate was 53.5% (37 of 69). There was a significantly higher metronidazole resistance rate among H pylori isolates from the asymptomatic controls (20 of 25) than the peptic ulcer disease subjects (17 of 44) (p = 0.0007). Twenty three of 32 (73%) women and 14 of 37 (38%) men harboured the metronidazole resistant strains. There was no sex or age difference as far as the prevalence of metronidazole resistant strains were concerned within each study group. Pre-treatment metronidazole susceptible H pylori were significantly more likely to respond to the triple therapy used than those with the metronidazole resistant ones (14 of 15 v five of 10) (p = 0.021).

Anti-Ulcer Agents↗
PubMed1996

Prevalence of CagA-bearing Helicobacter pylori strains detected by the anti-CagA assay in patients with peptic ulcer disease and in controls.

OBJECTIVE: Cytotoxin-associated gene (CagA)-bearing Helicobacter pylori strains have been associated with significant gastroduodenal pathologies. We have performed a study to evaluate the prevalence of CagA-bearing strains in a group of H. pylori-positive peptic ulcer disease and non-ulcer dyspepsia (NUD) patients, and healthy asymptomatic controls. METHOD: Two hundred ninety-seven peptic ulcer disease, 45 NUD subjects, and 200 asymptomatic controls were studied. The newly developed anti-CagA antibody assay was used for the purpose of this study. The assay was performed by a conventional three-step enzyme-linked immunosorbent assay (ELISA) to detect the concentration of anti-CagA antibody present in the tested sera against the recombinant CagA 17/12 fusion protein. The final results were expressed with reference to a standard curve constructed from pooled CagA+ sera. Anti-CagA antibody assay reproducibility was assessed by intraplate and interplate variations. RESULTS: The mean intraplate and interplate variations were 8.0% and 11.2%, respectively. Anti-CagA antibody was present in 165/197 (84%) duodenal ulcer disease, 80/100 (80%) gastric ulcer disease, 25/45 (55.6%) NUD subjects, and 29/100 (29%) asymptomatic controls. The ulcer disease subjects were significantly more likely than the NUD subjects and the asymptomatic controls to have a positive anti-CagA antibody assay ( p < 0.005 and p < 0.001, respectively). Moreover, the NUD subjects were more likely to be anti-CagA+ antibody than the asymptomatic controls (p < 0.005). CONCLUSIONS: This newly developed anti-CagA antibody assay was highly reproducible. Anti-CagA antibody positivity was present in a significantly higher percentage of peptic ulcer disease subjects than in non-ulcer and asymptomatic healthy controls. Thus, anti-CagA antibody can be used as a clinical marker for peptic ulceration.

Adult↗
PubMed1995

The importance of gastric emptying and mucosal folds in the adaptive cytoprotection of mild irritants in rats.

This study examines the involvement of gastric emptying and mucosal folds in the adaptive cytoprotection of different mild irritants against 100% ethanol-induced gastric mucosal damage. Pre-exposure to either 20% ethanol, 5% NaCl or 0.3M HCl significantly reduced the gastric mucosal damage caused by 100% ethanol in rats. Administration of either one of the three mild irritants increased the basal gastric residual volume and decreased the area occupied by gastric mucosal folds, but only 20% ethanol reduced the gastric emptying rate. Indomethacin (5 mg/kg, s.c.) pretreatment did not affect ethanol ulceration and gastric emptying rate when given by itself, but reversed the flattening of mucosal folds produced by the three mild irritants, and abolished the protective effect of 20% ethanol. These results suggest that the gastric adaptive cytoprotection induced by the three mild irritants acts through luminal dilution of the noxious agent, possibly caused by gastric retention. The reduction of mucosal folds could also contribute to the anti-lesion action of 20% ethanol. It is therefore suggested that the protective actions of the three mild irritants act through different mechanisms.

Adaptation, Physiological↗
PubMed1995

A comparison of two prostaglandin analogues (enprostil vs misoprostol) in the treatment of acute duodenal ulcer disease.

We conducted a clinical trial to compare the efficacy and safety profile of two prostaglandin analogues, enprostil (35 micrograms twice daily) and misoprostol (200 micrograms four times daily) in the treatment of acute duodenal ulcers in 214 patients. The two agents healed approximately 80% and in excess of 90% of duodenal ulcers after 4 and 6 weeks' therapy, respectively. There was a significantly lower ulcer healing rate in both treatment groups in smokers compared with non-smokers (P < 0.05). However, daytime and nighttime ulcer pain relief was achieved in fewer than 50% of patients by either agent. Diarrhea, which occurred in more than 40% of patients, was the predominant side effect, and occurred mainly during the first 2 weeks of therapy with either agent. Nevertheless, this side effect was mild and self-limiting in the majority of patients. Both agents were found to be safe and well tolerated by the majority of patients. We conclude that these prostaglandin analogues are safe and effective duodenal ulcer healing agents. Furthermore, there was very little difference between enprostil and misoprostol. The limiting factors, however, for their routine use as ulcer healing agents are their low efficacy with regard to ulcer pain relief and the high incidence of diarrhea.

Acute Disease↗
PubMed1995

Contributions of physical and chemical properties of mild irritants to gastric cytoprotection in rats.

The present study demonstrated the cytoprotective abilities of low concentrations of ethanol, NaCl and HCl, against the gastric mucosal damage caused by 100% ethanol, and the contributions of the physical and chemical properties of these mild irritants to their protective actions. The results have shown the differential protective effects of ethanol (10-40%), NaCl (2.5-12.5%) and HCl (0.15-0.45M), with the optimal cytoprotective concentrations being 20% ethanol, 5% NaCl and 0.3M HCl, respectively. Solutions of KCl and NaCl with similar osmolarity, and H2SO4 and HCl of similar acidity and osmolarity, all showed similar protective protective potentials as compared to the osmotic agent mannitol, which possessed a concentration- and tonicity-dependent protective action against 100% ethanol-induced mucosal damage. Some concentration of methanol, propan-2-ol and ethanol, having similar osmolarity with deionized water, exerted indifferent protective effects. It is therefore concluded that adaptive cytoprotection induced by low concentrations of NaCl and HCl could depend on their physical properties, while that of ethanol could act through its unique chemical property.

Animals↗
PubMed1995

Sucralfate in Helicobacter pylori eradication strategies.

BACKGROUND: Sucralfate monotherapy has been shown to suppress but not eradicate Helicobacter pylori. The combination of sucralfate with antibiotic(s) has been evaluated recently in the treatment of H. pylori-positive duodenal ulcer. The aim of this article is to review the efficacy of sucralfate-containing duotherapy and triple therapy in duodenal ulcer healing and H. pylori eradication rates. METHODS: Reports on duotherapy and triple therapy including sucralfate as the mediating agent were analysed to assess the duodenal ulcer healing and H. pylori eradication rates. RESULTS: One study on duotherapy with sucralfate and amoxycillin achieved an ulcer healing rate of 86% and H. pylori eradication rate of 40%, which compared favourably with sucralfate monotherapy that resulted in duodenal ulcer healing and H. pylori eradication rates of 65% and 0% respectively. A total of six studies have examined triple therapy using sucralfate with two antibiotics. The duodenal ulcer healing rates were generally over 90% and the H. pylori eradication rates about 80% (range 59% to 100%). In one comparative study, the 4-week duodenal ulcer healing and H. pylori eradication rates of sucralfate-containing triple therapy were not distinguishable from those of omeprazole-containing triple therapy. CONCLUSIONS: It is concluded that sucralfate is an effective mediating agent for the eradication of H. pylori in patients with duodenal ulcer.

Anti-Bacterial Agents↗
PubMed1995

Nonulcer dyspepsia: association with chronic Helicobacter pylori infection-related gastritis?

Nonulcer dyspepsia (NUD) is a highly prevalent yet poorly understood condition. Although Helicobacter pylori infection and its associated chronic gastritis are very common in patients with NUD, there is no convincing evidence to support their etiologic role in this condition on the basis of current literature review, nor is there any evidence that H. pylori-induced chronic atrophic (type B) gastritis causes the symptoms observed in NUD. Most studies that attempted to correlate H. pylori and NUD, by epidemiologic or therapeutic intervention studies, were flawed by the lack of appropriately matched controls. Despite significant improvement observed in most therapeutic studies in histologic gastritis after treatment with bismuth-containing compounds, with or without antibiotic(s), there is conflicting evidence about whether treatment confers any clinical benefits on NUD symptomatology. A validated, universally accepted objective scoring system is desperately needed so that future controlled studies can adopt the same or a similar system to evaluate the results observed in different centers and populations. Until a definitive, positive association between H. pylori infection and NUD, such as H. pylori infection and peptic ulcer disease, has been established, it would be futile to routinely look for evidence of H. pylori infection and/or to treat the infection with eradication therapy.

Chronic Disease↗
PubMed1994

Blood-group sialyl-Tn antigen is more specific than Tn as a tumor marker in the pancreas.

The aim of this study was to evaluate the expression of blood group Tn and sialyl-Tn antigens in the pancreas to determine whether they could help to interpret histochemically needle biopsies obtained from the pancreas. Lectin and immunohistochemistry was carried out using the biotin-labeled Vicia villosa agglutinin isolectin B4 and the mouse monoclonal antibody MLS102 to detect the Tn and sialyl-Tn blood-group antigens in the pancreas. All the pancreatic ductal adenocarcinomas (11/11) were positively stained by V. villosa agglutinin and MLS102 monoclonal antibody. None of the normals or chronic pancreatitics bound MLS102 monoclonal antibody. The acini of all the normals and chronic pancreatitics were V. villosa agglutinin positive, which was absent in the normal ductal cells and present only sparingly in the chronic pancreatitis ductal tissues (10/16). Thus, both the Tn and the sialyl-Tn blood-group antigens are present in pancreatic ductal tissues that have undergone malignant transformation. MLS102 is superior to V. villosa agglutinin in distinguishing malignant from normal and nonmalignant pancreatic tissues in needle biopsies.

Adenocarcinoma↗
PubMed1994

Helicobacter pylori epidemiology in relation to peptic ulcer and gastric cancer in south and north China.

Peptic ulcer disease is twice as common in people living in South China when compared with those in North China. However, the gastric cancer rate in North China is three times that of South China. The overall Helicobacter pylori prevalence rate is similar in North and South China populations and it is higher than Caucasians living in Western societies. However, there is a significantly higher prevalence of H. pylori seropositivity among those who live in the high gastric cancer areas of China. On the other hand, there is no significant difference in the H. pylori positive rate in the peptic ulcer disease patients between the two regions of China. Other permissive/associated co-factors in the development of peptic ulcer disease or gastric cancer remain unknown at this stage.

China↗
PubMed1994

Antacids. Indications and limitations.

Antacids have served us well for over a century. In terms of peptic ulcer disease, the attitude in the late 1950s to 1970s that antacids should be taken only on demand was unjustified and erroneous. 13 recent endoscopic controlled studies have confirmed the efficacy of antacids in the healing of duodenal ulcer, achieving about 75% healing in 4 weeks. The efficacy of antacids in promoting gastric ulcer healing has been less well studied and the results are controversial. The most appropriate and economical antacid regimens for the treatment of duodenal ulcer disease should include tablets or liquid that have acid neutralising capacity of 400 mmol/day given at least an hour after meals. As a long term therapy, antacids appear to work, but need be taken in multiple daily doses, a regimen which is unlikely to meet with long term patient compliance. Patients with gastro-oesophageal reflux disorders or pregnancy-related reflux have also benefited from the usage of antacids ad libitum. Early previous studies have clearly demonstrated the efficacy of antacids in reducing gastro-oesophageal reflux and healing of reflux oesophagitis. The acidity of the gastric contents is the major determining factor in the outcome of the aspiration pneumonitis occurring during delivery. The prophylactic use of antacids during delivery has helped to reduce the severity of this complication. Similarly, the prophylactic administration of antacid aiming to maintain gastric pH between 3.5 to 7.0 has resulted in significant reduction of bleeding due to stress associated ulcers and/or erosive haemorrhagic gastritis in critically ill patients. Antacid therapy, however, is controversial in the management of nonulcer dyspepsia or nonsteroidal anti-inflammatory drug related upper gastrointestinal mucosal damage. Undoubtedly, antacids have major roles to play in the treatment of gastric acid related disorders. They have clear advantages and disadvantages when compared with the antisecretory agents. New proton pump inhibitors in particular have certainly superseded antacids and even the H2-receptor antagonists in many respects. However, the long term safety record of antacids remains unsurpassed by any of the new antisecretory agents.

Antacids↗