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Biomedical subjects

S C Chung

Publications and source records attributed to S C Chung.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of Helicobacter pylori eradication on expression of cyclin D2 and p27 in gastric intestinal metaplasia.

BACKGROUND AND AIMS: Cyclins and cyclin-dependent kinase inhibitors play a crucial role in the control of cell cycle transitions. Enhanced expression of cyclin D2 and reduced expression of p27kip1 (p27) have been implicated in the pathogenesis of cancer. Because intestinal metaplasia has been regarded as a pre-malignant lesion, we investigated the expression of cyclin D2 and p27 in Helicobacter pylori-associated chronic gastritis with and without intestinal metaplasia, and followed the changes after H. pylori eradication. METHODS: Expression of cyclin D2 and p27 was studied by immunohistochemistry in 59 patients (including 35 patients with intestinal metaplasia) and in 10 gastric cancer patients. Among them, 29 H. pylori-infected patients had serial gastric biopsies taken before and at 1-year after eradication of H. pylori. RESULTS: Expression of cyclin D2 was significantly higher in gastric cancers when compared to their adjacent non-tumour tissues (median score 3 vs. 1, P=0.015). Over-expression of cyclin D2 was detected in H. pylori-associated chronic gastritis and intestinal metaplasia, which was reduced after eradication of the organism (median score 2 vs. 1, P=0.037 in chronic gastritis; median score 2 vs. 0, P=0.008 in intestinal metaplasia). While the normal gastric mucosa showed strong p27 expression, five of the 10 gastric cancer tissues exhibited reduced p27 expression (P=0.039). Diminished p27 expression was also seen in intestinal metaplasia, which was restored 1-year after H. pylori eradication (eight out of 16 vs. one out of 16, P=0.018). Reduced expression of p27 was frequently associated with increased cyclin D2 expression in H. pylori-associated intestinal metaplasia (P=0.02). CONCLUSION: Over-expression of cyclin D2 and reduced expression of p27 are closely linked to H. pylori-associated intestinal metaplasia. Eradication of H. pylori infection reverses the aberrant expression of cyclin D2 and p27 in intestinal metaplasia.

Cyclin D2↗
PubMed2001

Is non-Helicobacter pylori, non-NSAID peptic ulcer a common cause of upper GI bleeding? A prospective study of 977 patients.

BACKGROUND: Non-Helicobacter pylori, non-NSAID ulcer is relatively common in Western countries. Whether it is a significant problem in the Orient is unclear. The aim of this study was to investigate the incidence of non-H pylori, non-NSAID ulcers presenting with GI bleeding. METHODS: A prospective study was done of 1675 consecutive patients presenting with upper GI bleeding over a period of 12 months. Upper endoscopy was performed with biopsy specimens taken from the antrum and body of the stomach for a biopsy urease test (BUT) and histology for detection of H pylori. Exposure to nonsteroidal anti-inflammatory drugs (NSAID) or aspirin within 4 weeks of hospitalization was carefully scrutinized. A 6-week course of treatment with an H2-receptor antagonist was prescribed for patients who did not use an NSAID and had a negative BUT result. Follow-up endoscopy was performed to confirm H pylori status with a BUT and histology. Positive histology at either initial or follow-up endoscopy was used as the standard for diagnosing H pylori infection. RESULTS: Among 977 patients who were found to have ulcer bleeding, 434 (44%) had exposure to aspirin or an NSAID. Of the 543 non-NSAID users, 431 (79.4%) had a positive BUT and 112 (20.6%) were BUT negative on initial endoscopy. Eighty-nine of 112 patients who were NSAID negative, BUT negative returned for follow-up endoscopy. Forty-nine of 89 (55.1%) were found to have a positive BUT and positive histology at follow-up endoscopy. Only 40 of 977 (4.1%) patients admitted with ulcer bleeding were confirmed to have non-H pylori, non-NSAID ulcers. CONCLUSIONS: Non-H pylori, non-NSAID bleeding ulcer is uncommon. A negative BUT is unreliable for exclusion of H pylori infection during the acute phase of ulcer bleeding.

Adolescent↗
PubMed2001

Beta-endorphin infusion during exercise in rats does not alter hepatic or muscle glycogen.

The aim of this study was to determine whether beta-endorphin infusion influences liver or muscle glycogen concentration during exercise. Thirty-two rats (Harlan Co., IN, USA) with a body mass of 265-290 g were assigned at random to four groups, each of eight rats: (1) beta-endorphin infusion for 90 min at rest; (2) beta-endorphin infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade; (3) saline infusion (0.9% NaCl) for 90 min at rest; and (4) saline infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade. Beta-endorphin infusion elevated plasma beta-endorphin concentration by 2.5-fold at rest compared with saline infusion at rest, and by two-fold after exercise compared with saline infusion after exercise. Beta-endorphin infusion attenuated exercise-induced glucose concentration but did not alter the fasting hepatic glycogen concentration at rest or after exercise compared with saline infusion. Fasting hepatic glycogen decreased significantly as a result of 90 min of exercise independent of treatment. Deep intermedius muscle glycogen concentration at rest was similar after 90 min of both beta-endorphin and saline infusion and decreased significantly as a result of 90 min of exercise independent of treatment. Our results suggest that liver and muscle glycogenolysis is not responsible for the differences in plasma glucose with beta-endorphin infusion during exercise.

Animals↗
PubMed2001

Gastric choriocarcinoma shows characteristics of adenocarcinoma and gestational choriocarcinoma: a comparative genomic hybridization and fluorescence in situ hybridization study.

The authors report two cases of the rare primary gastric choriocarcinoma. These tumors showed an overwhelming predominance of cytotrophoblast- and syncytiotrophoblast-like tumor cells that were positive for beta-human chorionic gonadotrophin, with small foci of glandular differentiation. Beta-human chorionic gonadotrophin was also detected serologically in one patient. Comparative genomic hybridization study was performed on one specimen. Copy number gains of chromosomes 12, 17, 20, 22, and X, together with losses on 18q, were the major findings. Except for the gain of chromosome 12, which is known to be uncommon in primary gastric adenocarcinoma but frequently associated with choriocarcinoma, the remaining genomic imbalances were among the most common comparative genomic hybridization findings reported in primary gastric adenocarcinoma. Fluorescence in situ hybridization on paraffin sections of both specimens confirmed the presence of polysomy 17 and trisomy 12. These results suggest that primary gastric choriocarcinoma genetically possesses characteristics of both adenocarcinoma and gestational choriocarcinoma. The authors believe this is the first interphase cytogenetics study on this rare tumor, and that the results support the theory that gastric choriocarcinoma arises from alternate differentiation pathways of adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Circulating Epstein-Barr virus DNA in the serum of patients with gastric carcinoma.

PURPOSE: We investigated the detectability of EBV DNA in the serum of gastric carcinoma patients in Hong Kong. Previous data have shown that approximately 10% of gastric carcinomas in Hong Kong are associated with EBV. EXPERIMENTAL DESIGN: We recruited 51 patients with gastric carcinoma, 30 patients with gastritis, and 197 apparently healthy controls. For gastric carcinoma patients, blood samples were obtained before surgery. After surgery, the resected tumor samples from the cancer cases were subjected to in situ hybridization for small EBV-encoded RNA (EBER). Serum EBV DNA in all cases was measured by real-time quantitative PCR. RESULTS: Serum EBV DNA was detectable in 5 of 5 (100%) EBER-positive gastric carcinoma cases (median concentration, 1063 copies/ml), in 13 of 14 (93%) EBER-negative gastric carcinoma cases with EBER-positive infiltrating lymphocytes (median concentration, 50 copies/ml), and in 0 of 32 (0%) EBER-negative cases. In the nontumor controls, serum EBV DNA was detectable in 7 of 30 (23%) gastritis cases (median concentration, 0 copies/ml) and in 7 of 197 (3.6%) apparently healthy individuals (median concentration, 0 copy/ml). CONCLUSIONS: Our data indicate that serum EBV DNA reflects tumoral EBER status and opens up the possibility that circulating EBV DNA may be used as a tumor marker for the EBER-positive gastric carcinomas. The biological and clinical significance of the presence of low levels of circulating EBV DNA in the minority of gastritis patients and healthy individuals remains to be elucidated.

DNA, Viral↗
PubMed2000

Transhepatic balloon sphincteroplasty for bile duct stones after total gastrectomy.

Previous upper gastrointestinal surgery with the construction of a Roux-en-Y jejunal loop may prevent endoscopic access to the second part of the duodenum. We report a technique of percutaneous transhepatic balloon sphincteroplasty to facilitate the removal of common bile duct (CBD) stones. A 67-year-old woman presented with a 1-week history of right upper quadrant abdominal pain and fever, deranged liver function tests, and dilated intrahepatic ducts. The patient had previously had a total gastrectomy with Roux-en-Y reconstruction for a high-grade B-cell lymphoma of the stomach. Peroral endoscopic access to the biliary tree was unsuccessful. Percutaneous transhepatic cholangiography confirmed the presence of CBD stones. Over a period of 8 weeks, sequential dilatation of the percutaneous tract was undertaken. After a further 2 weeks, percutaneous choledochoscopy was performed. Several large stones were visualized and then fragmented. The choledochoscope would not pass through to the duodenum due to postinflammatory stenosis of the papilla, so the papilla was dilated with an endoscopic balloon. The remaining fragments were pushed through, and the duct was thoroughly irrigated with saline. Repeat cholangiography confirmed a clear CBD. Balloon catheter sphincteroplasty and biliary stone extrusion into the duodenum is a novel technique that enabled clearance of the CBD in an elderly patient who may otherwise have required open surgical exploration.

Aged↗
PubMed2000

Effect of intravenous omeprazole on recurrent bleeding after endoscopic treatment of bleeding peptic ulcers.

BACKGROUND: After endoscopic treatment of bleeding peptic ulcers, bleeding recurs in 15 to 20 percent of patients. METHODS: We assessed whether the use of a high dose of a proton-pump inhibitor would reduce the frequency of recurrent bleeding after endoscopic treatment of bleeding peptic ulcers. Patients with actively bleeding ulcers or ulcers with nonbleeding visible vessels were treated with an epinephrine injection followed by thermocoagulation. After hemostasis had been achieved, they were randomly assigned in a double-blind fashion to receive omeprazole (given as a bolus intravenous injection of 80 mg followed by an infusion of 8 mg per hour for 72 hours) or placebo. After the infusion, all patients were given 20 mg of omeprazole orally per day for eight weeks. The primary end point was recurrent bleeding within 30 days after endoscopy. RESULTS: We enrolled 240 patients, 120 in each group. Bleeding recurred within 30 days in 8 patients (6.7 percent) in the omeprazole group, as compared with 27 (22.5 percent) in the placebo group (hazard ratio, 3.9; 95 percent confidence interval, 1.7 to 9.0). Most episodes of recurrent bleeding occurred during the first three days, which made up the infusion period (5 in the omeprazole group and 24 in the placebo group, P<0.001). Three patients in the omeprazole group and nine in the placebo group underwent surgery (P=0.14). Five patients (4.2 percent) in the omeprazole group and 12 (10 percent) in the placebo group died within 30 days after endoscopy (P=0.13). CONCLUSIONS: After endoscopic treatment of bleeding peptic ulcers, a high-dose infusion of omeprazole substantially reduces the risk of recurrent bleeding.

Aged↗
PubMed2000

Is it safe to reuse disposable laparoscopic trocars? An in vitro testing.

BACKGROUND: The reuse of disposable laparoscopic instruments carries a risk of transmitting infectious diseases such as hepatitis and HIV. We evaluated the safety of reusing disposable trocars by studying the chances of their harboring infectious viruses after resterilization in an in vitro setting. METHODS: Disposable laparoscopic trocars were exposed to horse blood contaminated with high or low viral concentrations of herpes simplex virus type 1 (HSV1) and attenuated polio virus type 1 at room temperature for 2 h. HSV1 was chosen as the surrogate for lipid viruses that include hepatitis B and HIV virus; polio virus represented the nonlipid viruses that cause infections in immunocompromised patients and are more resistant to sterilization. The trocars were subsequently cleaned and resterilized by low-temperature steam and formaldehyde at 80 degrees C for 3 h. Viral cultures were then repeated after sterilization. RESULTS: A cytopathic effect (CPE) was demonstrated at both concentrations for HSV1 in all trocars before but not after sterilization. For the polio virus, CPE was evident in 50% of the trocars (two of four) exposed to high viral concentration after sterilization. CONCLUSION: Disposable trocars are difficult to resterilize and may harbor infectious viruses after their initial use. Therefore, the reuse of disposable trocars in laparoscopic surgery cannot be recommended.

Disposable Equipment↗
PubMed2000

Salvage therapies after failure of Helicobacter pylori eradication with ranitidine bismuth citrate-based therapies.

BACKGROUND: Salvage therapies after initial Helicobacter pylori eradication failure of ranitidine bismuth citrate (RBC)-based regimens remain undefined. AIM: To test the efficacy of 1-week omeprazole, amoxycillin and clarithromycin as a second-line treatment and 1-week quadruple therapy after repeated failures of RBC- and proton pump inhibitor-based regimens. METHOD: Patients were recruited from a recently published prospective randomized study if confirmed to have failed H. pylori eradication with RBC-based regimens. They were given omeprazole 20 mg, amoxycillin 1 g and clarithromycin 500 mg (OAC) b.d. for 1 week. 13C-urea breath test was performed 4 weeks after the conclusion of medication. Those who failed to respond to OAC were given 1-week quadruple therapy (bismuth subcitrate 120 mg, tetracycline 500 mg and metronidazole 400 mg q.d.s. plus omeprazole 20 mg b.d.). RESULTS: Among 398 patients receiving RBC-based therapies, 40 (10%) had failed eradication (RAC=7, RC-2=12, RMC=7, and RMT=14). OAC was prescribed to 31 patients (RAC=4, RC-2=9, RMC=6, and RMT=12) and 68% had successful eradication. Nine out of 10 patients with failed second treatment received quadruple therapy; successful eradication occurred in 83% (5 out of 6) after repeated failures of clarithromycin-based regimens. CONCLUSION: One-week OAC is not an optimal second-line therapy when RBC-clarithromycin combinations fail. Quadruple therapy appears to be effective despite repeated failures of clarithromycin-based RBC or proton pump inhibitor therapies.

Amoxicillin↗
PubMed2000

Helicobacter pylori infection is associated with milder gastro-oesophageal reflux disease.

BACKGROUND: We have previously demonstrated a negative relationship between the prevalence of Helicobacter pylori and gastro-oesophageal reflux disease (GERD). AIM: To study the effects of H. pylori infection on the severity of GERD. METHODS: Ethnic Chinese patients with frequent heartburn and/or endoscopic oesophagitis were studied. Endoscopic examination was performed to assess the severity of oesophagitis (modified Savary-Miller grading) and the presence of hiatus hernia. Biopsies were taken for rapid urease testing and confirmation of Barrett's oesophagus. Risk factors which may affect the severity of oesophagitis (age, sex, smoking, drinking, diabetes mellitus, hiatus hernia, H. pylori status and body mass index) were evaluated by a multiple regression model. The cagA status of H. pylori infected GERD and age-and-sex matched controls were determined by Western blot. Age-and-sex matched non-reflux patients were recruited as controls for comparison. RESULTS: Two hundred and twenty-five patients with GERD were studied, of whom 77 (34%) were infected with H. pylori. Oesophagitis and Barrett's oesophagus were found in 140 patients (62%) and six patients (3%), respectively. H. pylori infected patients had significantly less severe oesophagitis compared to the uninfected group (P=0.022). All patients with Barrett's oesophagus were uninfected. Factors that predicted severe oesophagitis included age over 60 years (P < 0.001) and hiatus hernia (P < 0.001). H. pylori infection was the only factor that showed a negative correlation with severe oesophagitis (P=0.011). The prevalence of the cagA positive strain in endoscopy-negative GERD, erosive oesophagitis and control subjects was 70, 76 and 78%, respectively (P=0.75). CONCLUSIONS: H. pylori infection is associated with milder GERD.

Adult↗
PubMed2000

Interaction of Helicobacter pylori eradication and non-steroidal anti-inflammatory drugs on gastric epithelial apoptosis and proliferation: implications on ulcerogenesis.

BACKGROUND: Apoptosis is associated with loss of gastric mucosal integrity and may play an important role in ulcer development. AIM: To examine how Helicobacter pylori and NSAIDs interact to effect apoptosis and proliferation of the gastric mucosa. METHODS: Patients presenting with musculoskeletal pain requiring NSAID treatment and without previous exposure to NSAID or pre-existing ulcers were recruited. Patients were divided into three groups: (A) H. pylori-infected; (B) H. pylori-eradicated; and (C) non-infected patients. They were given naproxen for 8 weeks. Patients with non-ulcer dyspepsia and H. pylori infection who were given anti-Helicobacter therapy were recruited as controls (D). Endoscopy was performed at baseline and 8-weeks after receiving naproxen. Gastric antral biopsies were obtained to assess apoptosis by terminal uridine deoxynucleotidyl nick end-labelling (TUNEL) and proliferation by Ki67 immunostaining. RESULTS: A total of 55 patients were studied. H. pylori-positive patients had a higher apoptosis and proliferation index at baseline than non-infected patients (P < 0.0001), and eradication of H. pylori resulted in a significant reduction in these parameters. The NSAID induced apoptosis in non-infected subjects (P=0.03) whilst apoptosis was reduced in H. pylori-positive patients receiving NSAID (P=0.02). After 8 weeks of NSAID, post-treatment apoptosis was significantly higher in patients with persistent H. pylori infection than in non-infected patients (P=0.01). CONCLUSIONS: Eradication of H. pylori prior to NSAID therapy significantly reduces the level of apoptosis in the gastric mucosa, which may contribute to maintaining mucosa integrity and preventing ulcer development.

Adult↗
PubMed2000

Surgery in the acute management of bleeding peptic ulcer.

The management of bleeding peptic ulcers is an increasing challenge in an ageing population. Endoscopic therapy reduces the need for emergency surgery in bleeding peptic ulcers, and ulcers that fail endoscopic therapy are often 'difficult' ulcers, highly demanding for most gastric surgeons. Mortality in patients requiring eventual salvage surgery is high. Planned urgent surgery is preferable to emergency surgery in elderly patients. Initial endoscopic control offers an opportunity for selecting high-risk ulcers for early surgery. Such a logical approach has, however, not been supported by evidence in the literature. At surgery, an aggressive approach is recommended. Post-operative bleeding is more common after lesser surgery, and this complication is often fatal. When re-bleeding occurs, a selective approach is suggested as emergency surgery carries with it a substantial mortality. Large chronic ulcers with exigent bleeding are less likely to respond to endoscopic re-treatment. Expedient surgery is advised for these patients.

Acute Disease↗
PubMed2000

Neck ultrasound in staging squamous oesophageal carcinoma - a high yield technique.

AIM: This study evaluates the use of neck ultrasound in staging squamous oesophageal carcinoma. MATERIALS AND METHODS: A prospective analysis of the clinical, neck ultrasound (US) and thoraco-abdominal computed tomography (CT) findings in 121 patients with squamous oesophageal carcinoma at presentation was performed. The relationship between malignant neck nodes, mediastinal and abdominal adenopathy, location and size of the primary tumour was analysed. RESULTS: Ten of 121 patients (8%) had clinically palpable neck nodes which were deemed malignant in six (5%) following US and fine-needle aspiration for cytology. Of those 111 patients with no palpable neck nodes, 31 (28%) had malignant nodes shown on US. The more cephalad the location of the primary tumour, the higher the frequency of malignant neck nodes which were found in 80%, 52%, 29% and 9% of cervical, upper thoracic, mid-thoracic and lower thoracic oesophageal tumours, respectively. Eleven (29%) of the 38 patients with malignant neck nodes shown on US had no CT evidence of additional adenopathy in the mediastinum or upper abdomen. Neck US altered TNM staging in 22/121 (18%) patients at presentation. CONCLUSION: Neck US frequently detects clinically impalpable metastatic nodes leading to altered TNM staging in patients with squamous oesophageal carcinoma. We advocate its routine use when staging squamous oesophageal carcinoma.

Adult↗
PubMed2000

Atrophy and intestinal metaplasia one year after cure of H. pylori infection: a prospective, randomized study.

BACKGROUND & AIMS: Helicobacter pylori-infected gastric mucosa evolves through stages of chronic gastritis, intestinal metaplasia (IM), glandular atrophy (GA), and dysplasia before carcinoma develops. We studied if H. pylori eradication would alter the course of premalignant histologic changes in the stomach. METHODS: Volunteers from the Yantai County in China underwent upper endoscopy with biopsy specimens obtained from the antrum and corpus. H. pylori-infected subjects were randomized to receive either a 1-week course of omeprazole, amoxicillin, and clarithromycin (OAC) or placebo. At 1 year, endoscopies with biopsies were repeated. RESULTS: A total of 587 H. pylori-infected subjects were randomized to OAC (n = 295) and placebo (n = 292). At 1 year, H. pylori was eradicated in 226 subjects assigned to OAC. In the placebo group, 245 patients remained H. pylori infected. Analysis of paired samples obtained from the same patients showed that acute and chronic gastritis decreased in both the antrum and corpus after H. pylori eradication (P<0.001) and activity of IM decreased in antrum (P = 0.014). In the H. pylori-infected group, antral biopsy specimens had more pronounced acute gastritis (P = 0.01), whereas corpus specimens showed increased acute and chronic gastritis (P<0.001) and a marginal increase in GA (P = 0.052). When histologic changes were compared between the 2 groups, decrease in acute and chronic gastritis was more frequent after H. pylori eradication (P<0.001) but changes in IM were similar. In the H. pylori-infected group, increase in GA was seen in the corpus (P = 0.01). CONCLUSIONS: At 1 year, H. pylori eradication is beneficial in preventing progression of pathologic changes of the gastric mucosa.

Adult↗
PubMed2000

Aeromonas infection in acute suppurative cholangitis: review of 30 cases.

OBJECTIVES: Aeromonads, though not common pathogens in biliary sepsis, caused substantial mortality in patients with impaired hepatobiliary function. Our aim was to study the pathogenic role of Aeromonas in acute suppurative cholangitis. METHODS: Between 1996 and 1998, the medical records of patients with a diagnosis of biliary sepsis were reviewed. Those who fulfilled the diagnostic criteria for acute suppurative cholangitis and had positive bile or blood cultures for Aeromonas species were studied. RESULTS: One thousand and forty-five patients were confirmed to have acute suppurative cholangitis. Of these, 30 patients (2.9%) had Aeromonas species isolated from bile; four were complicated by aeromonas septicaemia with simultaneous recovery of the bacteria from blood. All except two isolates were A. hydrophila. Twenty-four patients (80%) had bile duct stones, four (13%) had cholangiocarcinoma and two (7%) pancreatic cancer. Twenty-five cases (83%) had previous exploration of the biliary tract. There was substantial resistance to piperacillin (58%), ceftazidime (30%) and imipenem (15%). Most patients improved after biliary decompression. Only three patients (10%) died, two had terminal malignancy and one had end-stage liver failure. No excess mortality was attributable to Aeromonas infection in biliary sepsis. CONCLUSIONS: Previous instrumentation facilitated ascending Aeromonas infection of the biliary tract from the gastrointestinal tract. Unlike early reports, our results showed that aeromonads did not adversely affect the clinical outcome of acute suppurative cholangitis with successful drainage of biliary obstruction.

Acute Disease↗