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Biomedical subjects

J J Sung

Publications and source records attributed to J J Sung.

At least 19 recordsLinked to original sources
PubMed2007

Trans-cutaneous electrogastrographic study of gastric myoelectric activity in transposed intrathoracic stomach after esophagectomy.

We examined the feasibility of trans-cutaneous electrogastrography (EGG) in recording myoelectric activity of the transposed thoracic stomach after esophagectomy. Nineteen patients who had Ivor-Lewis esophagectomy were studied. The EGG signal was recorded using cutaneous electrodes placed over the lower sternum. Eleven patients who underwent total gastrectomy served as controls. Normal rhythm pattern (2.4-3.6 cpm > or = 70%) and power ratio (PR > or = 2) was observed in five and 12 patients, respectively, after esophagectomy. The observation of normal gastric rhythm was more frequent in the postprandial period in the esophagectomy group (median 42.6%vs. 7.4%, P = 0.01), and the PR was significantly higher (median 2.27 vs. 1.38, P = 0.013) than the gastrectomy group. Feeding further increased the prevalence of normal gastric slow wave in the esophagectomy group (median 14.8% to 42.6%, P = 0.002) and improved the stability of dominant frequency (median 78% to 67%, P = 0.015). We conclude that gastric myoelectric activities of thoracic transposed stomach can be detected from cutaneous sternal electrodes. This represented a preservation of gastric motility even when the stomach is pulled up to the thorax as a substitute for the esophagus.

Case-Control Studies↗
PubMed2006

Role of laboratory variables in differentiating SARS-coronavirus from other causes of community-acquired pneumonia within the first 72 h of hospitalization.

The Centers for Disease Control and Prevention (CDC) recommend that SARS-coronavirus (SARS-CoV) testing be considered in epidemiologically high-risk patients hospitalized with community-acquired pneumonia (CAP) if no alternative diagnosis is identified after 72 h. The aim of this study was to identify routine laboratory variables that might indicate the need for SARS-CoV testing. Routine hematological/biochemical variables in patients with laboratory-confirmed SARS (2003) were compared with those in consecutive patients hospitalized June-December 2004 with radiologically confirmed CAP. Stepwise logistic regression analyses were performed to identify discriminating variables at baseline and by day 3 of hospitalization. Nasopharyngeal aspiration and antigen detection for influenza virus and respiratory syncytial virus using an immunofluorescence assay (IFA) were routinely performed in patients with CAP. Altogether, 181 patients with CAP (who remained undiagnosed by IFA) and 303 patients with SARS were studied. The mean intervals from symptom onset to admission were 3.1 and 2.8 days, respectively (p > 0.05). The etiological agent of CAP was identified retrospectively in only 39% of cases, the majority being bacterial pathogens. At baseline, age and absolute neutrophil count (ANC) were the only independent discriminating variables (p < 0.0001). Using a value of <4.4 x 10(9)/l as the cutoff for ANC, the sensitivity and specificity of ANC for discriminating SARS were 64 and 95%, respectively (AUC 0.90). By day 3 of hospitalization, age (p < 0.0001), change in ANC (p = 0.0003), and change in bilirubin (p = 0.0065) were discriminating variables. A model combining age <65 years, a change in ANC of >-3 x 10(9)/l, and a change in bilirubin of > or =0 mmol/l had a sensitivity of 43% and a specificity of 95% for SARS (AUC 0.90). There are only a few laboratory features (including lymphopenia) that clearly discriminate SARS from other causes of CAP. Nevertheless, when evaluating epidemiologically high-risk patients with CAP and no immediate alternative diagnosis, a low ANC on presentation along with poor clinical and laboratory responses after 72 h of antibiotic treatment may raise the index of suspicion for SARS and indicate a need to perform SARS-CoV testing.

Aged↗
PubMed2005

Accuracy of endoscopic ultrasonography in diagnosing ascites and predicting peritoneal metastases in gastric cancer patients.

BACKGROUND: Preoperative diagnosis of peritoneal metastases (PM) is difficult in patients with gastric cancer (GC). AIMS: To assess the accuracy of endoscopic ultrasonography (EUS) in diagnosing ascites and its predictability for the presence of PM in GC patients. SUBJECTS: Consecutive patients with newly diagnosed GC from 1998 to 2004 were studied. METHODS: All patients underwent EUS, ultrasound (US), and computed tomography (CT) scan for preoperative staging and the presence of ascites. The results were compared with operative findings. The diagnosis of PM was confirmed by histopathology or peritoneal fluid cytology. RESULTS: A total of 301 patients were recruited and in 250 patients the presence of ascites (n = 93) and PM (n = 71) were confirmed. EUS was more sensitive (87.1%) than combined US and CT scan examinations (16.1%) and operative findings (laparoscopy or laparotomy) (40.9%) in diagnosing ascites. Sensitivity, specificity, positive and negative predictive values, and accuracy for predicting the presence of PM were 73%, 84%, 64%, 89%, and 81% by EUS; 18%, 99%, 87%, 75%, and 76% by combining US and CT scan; and 77%, 94%, 83%, 91%, and 89% by operative findings, respectively. In multivariate logistic regression analysis, EUS detected ascites was the only significant independent predictor for the presence of PM (p<0.001; odds ratio 4.7 (95% confidence interval 2.0-11.2)). CONCLUSION: EUS is a sensitive method for diagnosing ascites which is an important predictive factor for the presence of PM in GC patients.

Adenocarcinoma↗
PubMed2002

Comparison of two new rapid serology tests for diagnosis of Helicobacter pylori infection in Chinese patients.

BACKGROUND: Rapid serology test is a simple and convenient way for diagnosing Helicobacter pylori infection. However performances of these tests are usually less satisfactory than expected, particularly in developing countries. AIM: To evaluate the performances of two newly developed rapid serology tests for Helicobacter pylori infection. PATIENTS: Consecutive Chinese dyspeptic patients undergoing upper gastrointestinal endoscopy. METHODS: Gastric biopsies were obtained from antrum and corpus for rapid urease test and histological examination. Diagnosis of Helicobacter pylori infection was based on two or more positive results in rapid urease test, histology and [13C] urea breath test. Patients' sera were tested against two rapid serology tests: ASSURE Hp Rapid Test (Genelabs Diagnostics, Singapore) and SureStep (Applied Biotech, San Diego, CA, USA). RESULTS: A total of 148 patients were evaluated and Helicobacter pylori infection was diagnosed in 78 (53%) patients by gold standard. The sensitivities of ASSURE Hp and SureStep were, respectively, 94% and 71% (p=0.0003). Specificities of the two test kits were both 90%. The overall accuracy of ASSURE Hp was significantly higher than SureStep (92% versus 80%, p=0.004). CONCLUSION: Both rapid serology tests appear to be specific in diagnosing Helicobacter pylori infection in the Chinese populations. However the ASSURE Hp test is more sensitive and accurate than the SureStep test.

Adult↗
PubMed2001

Alterations of frizzled (FzE3) and secreted frizzled related protein (hsFRP) expression in gastric cancer.

Wnt signaling pathway is important for development and carcinogenesis. Alterations of this pathway, such as mutations in adenomatous polyposis coli (APC) gene and activation mutations of beta-catenin, would result in stabilization of beta-catenin and subsequent translocation to nucleus where genes are transcribed. Recently, a receptor of Wnt, FzE3 was found to be up-regulated in esophageal carcinoma while a non-receptor antagonist of Wnt, secreted frizzled related protein (hsFRP) was found to be down-regulated in some cancer. These findings suggested that FzE3 is a potential oncogene while hsFRP is a potential tumor suppressor gene. We aimed to investigate whether FzE3 and hsFRP were altered in gastric cancer. Twelve cases of gastric cancer, including 7 cases of intestinal type, 4 cases of diffuse type and I case of mixed type, were studied. FzE3 and hsFRP mRNAs were expressed in most of the paired normal gastric tissues. FzE3 was over-expressed in 9 cases (75%) of gastric carcinoma tissues while hsFRP was down-regulated in 2 cases (16%). Beta-catenin nuclear staining was identified in 3 cases (27%) and cyclin D1 was expressed in 5 cases (41%) of cancer samples. All these cases were associated with either up-regulation of FzE3 or down-regulation of hsFRP. Our results suggested that alterations of FzE3 or hsFRP were frequent in gastric cancer. These provide alternative mechanisms leading to activation of Wnt signaling pathway in gastric carcinogenesis.

Adenocarcinoma↗
PubMed2001

Inverse association between cyclooxygenase-2 overexpression and microsatellite instability in gastric cancer.

This study examined the association between cyclooxygenase-2 (COX-2) overexpression and microsatellite instability (MSI) in gastric cancer. COX-2 expression was assessed by immunohistochemistry and scored in a semi-quantitative manner whereas MSI status was characterized by nine microsatellite markers. The clinicopathological features of cancers including survival data were analyzed. Of the 109 gastric cancers studied, COX-2 overexpression and high level of MSI (MSI-H) was detected in 64.2 and 22.0% cases respectively. Gastric tumors with MSI-H phenotypes had significantly lower level of COX-2 expression levels when compared to MSI-L and MSS tumors (P=0.002). Moreover, COX-2 overexpression was associated with tumor invasion beyond submucosa (P=0.045) and there was a trend favoring better survival in gastric cancers without COX-2 overexpression (P=0.07). The results from this study suggest that gastric cancer with microsatellite instability or COX-2 overexpression present with diverse clinicopathological features.

Cohort Studies↗
PubMed2001

Concurrent hypermethylation of multiple tumor-related genes in gastric carcinoma and adjacent normal tissues.

BACKGROUND: Transcriptional silencing by CpG-island hypermethylation now is believed to be an important mechanism of tumorigenesis. To date, studies on CpG-island hypermethylation in gastric carcinoma and adjacent normal tissues are few. METHODS: The authors examined 5 gastric carcinoma cell lines, 26 frozen gastric carcinoma tissues and their adjacent nontumor area for concurrent CpG-island hypermethylation in 6 tumor-related genes (p15, p16, E-cadherin, GST-pi, hMLH1, and VHL) by methylation-specific polymerase chain reaction. Nontumorous gastric tissues from 10 gastritis patients were used as controls. RESULTS: Hypermethylation was not detected in any tissue taken from gastritis patients but was identified in all 5 cell lines and in 24 (92.3%) gastric carcinoma patients. CpG-island methylation in tumor-related genes also was detected in 7 out of the 25 adjacent normal tissues from cancer patients. Hypermethylation of E-cadherin, p15, and p16 were detected more frequently than GST-pi and hMLH1, whereas aberrant methylation of VHL was not detected. Concurrent hypermethylation in 2 or more tumor-related genes was detected in 3 out of the 5 gastric carcinoma cell lines, 22 (84.6%) tumor samples, and 5 (20%) adjacent gastric tissues. Eighteen (69.2%) tumor samples showed hypermethylation in >or= 3 genes. CONCLUSIONS: The current study showed that concurrent hypermethylation of multiple tumor-related genes is detected frequently in gastric carcinoma and adjacent normal tissues. Study findings suggested that a mechanism that leads to dysregulation in CpG-island methylation is likely to be involved in the early gastric carcinogenesis process.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Preventing recurrent upper gastrointestinal bleeding in patients with Helicobacter pylori infection who are taking low-dose aspirin or naproxen.

BACKGROUND: Many patients who have had upper gastrointestinal bleeding continue to take low-dose aspirin for cardiovascular prophylaxis or other non-steroidal antiinflammatory drugs (NSAIDs) for musculoskeletal pain. It is uncertain whether infection with Helicobacter pylori is a risk factor for bleeding in such patients. METHODS: We studied patients with a history of upper gastrointestinal bleeding who were infected with H. pylori and who were taking low-dose aspirin or other NSAIDs. We evaluated whether eradication of the infection or omeprazole treatment was more effective in preventing recurrent bleeding. We recruited patients who presented with upper gastrointestinal bleeding that was confirmed by endoscopy. Their ulcers were healed by daily treatment with 20 mg of omeprazole for eight weeks or longer. Then, those who had been taking aspirin were given 80 mg of aspirin daily, and those who had been taking other NSAIDs were given 500 mg of naproxen twice daily for six months. The patients in each group were then randomly assigned separately to receive 20 mg of omeprazole daily for six months or one week of eradication therapy, consisting of 120 mg of bismuth subcitrate, 500 mg of tetracycline, and 400 mg of metronidazole, all given four times daily, followed by placebo for six months. RESULTS: We enrolled 400 patients (250 of whom were taking aspirin and 150 of whom were taking other NSAIDs). Among those taking aspirin, the probability of recurrent bleeding during the six-month period was 1.9 percent for patients who received eradication therapy and 0.9 percent for patients who received omeprazole (absolute difference, 1.0 percent; 95 percent confidence interval for the difference, -1.9 to 3.9 percent). Among users of other NSAIDs, the probability of recurrent bleeding was 18.8 percent for patients receiving eradication therapy and 4.4 percent for those treated with omeprazole (absolute difference, 14.4 percent; 95 percent confidence interval for the difference, 4.4 to 24.4 percent; P=0.005). CONCLUSIONS: Among patients with H. pylori infection and a history of upper gastrointestinal bleeding who are taking low-dose aspirin, the eradication of H. pylori is equivalent to treatment with omeprazole in preventing recurrent bleeding. Omeprazole is superior to the eradication of H. pylori in preventing recurrent bleeding in patients who are taking other NSAIDs.

Anti-Bacterial Agents↗
PubMed2001

Somatic beta-catenin mutation in gastric carcinoma--an infrequent event that is not specific for microsatellite instability.

We screened 90 cases of gastric carcinoma (GCA) samples for beta-catenin exon 3 mutation and assessed its possible relationship with microsatellite instability (MSI). Three mutations were detected in two samples, including a single mutation in an intestinal type and double mutations in a diffuse type GCA. One of the mutations found in the diffuse type GCA sample was a non-sense mutation at codon 68 (CAG-->TAG). This novel mutation was predicted to disrupt the binding of beta-catenin to alpha-catenin and may be related to the diffuse type morphology. The other two mutations were missense mutations involved or related to the GSK-3beta phosphorylation site, which have been reported previously. No MSI can be demonstrated in the two cases with beta-catenin mutation. Our results suggested that beta-catenin mutation was infrequent in GCA and appeared not specific for MSI.

Adult↗
PubMed2001

Association between cyclo-oxygenase-2 overexpression and missense p53 mutations in gastric cancer.

Wild-type p53 competitively binds to the promoter region of COX-2 in vitro and inhibits its transcription. We examined the association between p53 mutation and COX-2 expression in gastric cancer. COX-2 over-expression was seen in 19 (48.7%) cases. These tumours had more lymph-node metastasis (P = 0.048) and tended to have a poorer survival (P = 0.07). Missense mutations of p53 were detected in 20 (51.3%) patients and had a significantly stronger COX-2 expression than tumours without p53 mutation (P = 0.016). Our results suggest a link between p53 mutation and COX-2 overexpression in gastric cancer.

Adult↗
PubMed2001

Management of nonsteroidal anti-inflammatory drug-related peptic ulcer bleeding.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have superseded Helicobacter pylori infection as the most important cause of peptic ulcer bleeding. Eradication of H. pylori in NSAID users will not affect ulcer healing. In high-risk patients with a history of ulcer bleeding, curing H. pylori infection alone without acid suppression has substantially reduced the risk of rebleeding caused by low-dose aspirin but not nonaspirin NSAIDs. In a study comparing the safety profile of misoprostol in combination with NSAID against nabumetone in high-risk patients with a history of ulcer bleeding, both strategies were unable to confer significant protection against the risk of rebleeding.

Anti-Bacterial Agents↗
PubMed2001

Up-regulation of cyclooxygenase-1 and -2 in human gastric ulcer.

BACKGROUND: The expression of cyclooxygenase (COX) in human gastric ulcers is unknown. AIM: To study the expression and cellular localization of cyclooxygenase in human gastric ulcers. METHODS: A total of 38 surgical gastric ulcer specimens were studied; 20 were Helicobacter pylori-positive and 18 were associated with NSAID use. Twenty non-ulcerated, histologically normal gastric specimens were used as controls. The cellular localization of COX-1 and COX-2 were determined by immunohistochemistry and double immunofluorescence. Cyclooxygenase messenger RNA (mRNA) was measured by reverse transcription-polymerase chain reaction and localized by in situ hybridization. RESULTS: In control specimens, COX-1 was detected in stromal cells in the lamina propria. There was focal and weak immunostaining for COX-2 in the foveolar epithelium. At the ulcer edge, COX-1 was significantly increased in lamina propria cells whereas COX-2 was strongly expressed in the hyperplastic foveolar epithelium in H. pylori- and non-steroidal anti-inflammatory drugs (NSAID)-associated ulcers. At the ulcer base, there was strong expression of COX-1 and COX-2 in myofibroblasts, macrophages and endothelial cells in the granulation tissue, irrespective of H. pylori status or NSAID use. Messenger RNA of COX-1 and COX-2 were demonstrated by reverse transcription-polymerase chain reaction. Double immunofluorescence and in situ hybridization confirmed the cellular localization of cyclooxygenase at protein and mRNA levels, respectively. CONCLUSION: Both COX-1 and COX-2 are up-regulated in human gastric ulcers.

Adult↗
PubMed2001

Randomized trial of low-dose misoprostol and naproxen vs. nabumetone to prevent recurrent upper gastrointestinal haemorrhage in users of non-steroidal anti-inflammatory drugs.

BACKGROUND: Prophylactic misoprostol or non-steroidal anti-inflammatory drugs (NSAIDs) with low gastric toxicity (nabumetone) has been shown to reduce mucosal injury. AIM: To compare nabumetone vs. co-therapy of naproxen with low-dose misoprostol for secondary prevention of upper gastrointestinal bleeding in NSAID users. METHODS: NSAID users presenting with upper gastrointestinal bleeding were enrolled if they required long-term NSAIDs. After ulcer healing, they were randomized to receive: naproxen (500-1000 mg/day) and misoprostol (200 microg b.d.), or nabumetone (1000-1500 mg/day) and placebo misoprostol for 24 weeks. The primary end-point was recurrent upper gastrointestinal bleeding. The secondary end-point was the proportion of patients suffering from major gastrointestinal events including ulcer bleeding, symptomatic ulcers and severe dyspepsia. RESULTS: A total of 90 patients were included in the intention-to-treat analysis (misoprostol/naproxen 45, nabumetone 45). Recurrent bleeding occurred in 10 patients (22.2%) receiving misoprostol/naproxen compared with three (6.7%) receiving nabumetone (relative risk 3.33, 95% CI: 0.98-11.32, P=0.069). The proportion of patients suffering from major gastrointestinal events at 24 weeks was 31.1% in the misoprostol/naproxen group and 28.9% in the nabumetone group. CONCLUSIONS: Misoprostol/naproxen is not superior to nabumetone for secondary prevention of upper gastrointestinal bleeding. Neither low-dose misoprostol nor nabumetone is adequate for high-risk NSAID users.

Adult↗
PubMed2001

Validation of a new immunoblot assay for the diagnosis of Helicobacter pylori in the Asian population.

BACKGROUND: Performance of commercial serological tests for Helicobacter pylori varies in different populations, largely due to strain heterogeneity and variations in antigenic preparations. Currently available serology tests often show sub-optimal accuracy when used for Asian patients. AIM: This study evaluated a recombinant antigen-based immunoblot for the diagnosis of H. pylori infection in Chinese patients, and compared it with a conventional ELISA test. METHODS: Dyspeptic patients referred for diagnostic endoscopy were recruited. The gold standard for H. pylori infection was based on two or more positive results among rapid urease test, histology and (13)C-urea breath test. Serological diagnosis of H. pylori infection was conducted by an ELISA test (pylori DTect; Diagnostic Technology) and an immunoblotting against a novel recombinant antigen (C1S; Genelab), which was constructed by immunological screening of the genomic DNA library of H. pylori. RESULTS: A total of 87 patients were evaluated and H. pylori infection was diagnosed in 40 (46%) by the reference tests. The sensitivities of the ELISA and immunoblot were 80% (95% CI: 64--91%) and 90% (95% CI: 76--97%), whilst the specificities were 96% (95% CI: 86--96%) and 87% (95% CI: 74--95%), respectively. The respective likelihood ratios of the two tests were 18.6 and 7.0. CONCLUSIONS: Satisfactory performance is obtained by the use of the new recombinant antigen-based immunoblot for diagnosing H. pylori infection in Chinese patients.

Adult↗
PubMed2001

Expression and cellular localization of COX-1 and -2 in Helicobacter pylori gastritis.

BACKGROUND: There are conflicting reports on the expression of cyclooxygenase in Helicobacter pylori infection. AIM: To evaluate the expression of COX-1 and COX-2 in H. pylori gastritis at messenger RNA (mRNA) and protein levels. METHODS: Endoscopic gastric biopsies were obtained from patients with non-ulcer dyspepsia. The levels of COX-1 and COX-2 mRNA were compared between H. pylori-infected and uninfected specimens using reverse transcription-polymerase chain reaction. The immunohistochemical findings were correlated with the cellular localization of cyclooxygenase mRNA using in situ hybridization. RESULTS: A total of 40 H. pylori-infected and 40 uninfected specimens were studied. mRNA of COX-2 but not COX-1 was elevated in H. pylori-infected mucosa. COX-1 was localized to the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria. COX-2 was barely detectable in uninfected mucosa but was strongly expressed in the foveolar and glandular epithelia in H. pylori gastritis. CONCLUSION: Cyclooxygenase-1 is expressed in the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria irrespective of the H. pylori status. By contrast, H. pylori induces COX-2 expression in the foveolar and glandular epithelia.

Adult↗
PubMed2001

Economic analysis of four triple regimens for the treatment of Helicobacter pylori-related peptic ulcer disease in in-patient and out-patient settings in Hong Kong.

BACKGROUND: One-week triple regimens have been shown to be effective for the treatment of Helicobacter pylori-related peptic ulcer disease. AIM: To conduct an economic analysis of four triple regimens for the treatment of H. pylori-related peptic ulcer disease from the perspective of a public health organization in Hong Kong. METHODS: Records of 200 patients with H. pylori-related peptic ulcer disease, who had previously participated in a randomized comparison of ranitidine bismuth citrate (RBC) with amoxicillin and clarithromycin (RAC), omeprazole with amoxicillin and clarithromycin (OAC), RBC with metronidazole and tetracycline (RMT), or, colloidal bismuth subcitrate with metronidazole and tetracycline (BMT) in either in-patient or out-patient setting were reviewed. RESULTS: Fifty patients were excluded because of incomplete documentation or lack of peptic ulcer. In the out-patient group (n=72), the median direct costs of the RAC group (HK $ 5094) were lower those of the BMT (HK $ 5400), RMT (HK $ 5394), or OAC (HK $ 5440) groups, but the difference was significant only between the RAC and BMT groups (P < 0.05). In the in-patient group (n=78), the median direct costs of the RMT group (HK $ 8524) were significantly lower than those of the OAC (HK $ 13 871) and RAC (HK $ 12 092) groups (P < 0.05), but were similar to those of the BMT group (HK $ 8758). CONCLUSIONS: RAC and RMT are the least costly regimens for out-patient and in-patient treatment, respectively, of H. pylori-related peptic ulcer disease in Hong Kong.

Adolescent↗