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Biomedical subjects

J Y Kang

Publications and source records attributed to J Y Kang.

At least 19 recordsLinked to original sources
PubMed1998

Gastroesophageal reflux disease is a common cause of noncardiac chest pain in a country with a low prevalence of reflux esophagitis.

Gastroesophageal reflux disease is believed to be uncommon in the East. This study aimed to determine if such a condition was a significant cause of noncardiac chest pain in Singapore. Eighty consecutive patients with recurrent chest pain, who had cardiac and other obvious causes excluded, underwent esophagogastroduodenoscopy, standard manometry, acid perfusion test, and prolonged ambulatory pH and pressure monitoring. Endoscopic esophagitis, positive acid perfusion tests, pathologic reflux, and positive chest pain-reflux correlation were detected in 7/80 (8.8%), 11/70 (15.7%), 14/61 (23.0%), and 12/25 (48.0%) patients, respectively. Among those with pathologic reflux, endoscopic esophagitis was present in only two (14.3%). Overall, 32 (40%) patients had gastroesophageal reflux disease. Esophageal motility disorder, alone or in association with gastroesophageal reflux disease, was demonstrated in only five (6.3%) patients. Our results confirmed western reports that gastroesophageal reflux disease was a common cause of noncardiac chest pain, whereas motility disorder was an infrequent cause of such pain.

Adult↗
PubMed1998

Suppression of mouse skin tumor promotion and induction of apoptosis in HL-60 cells by Alpinia oxyphylla Miquel (Zingiberaceae).

There have been considerable efforts to search for naturally occurring substances for the intervention of carcinogenesis. Many components from dietary or medicinal plants have been identified that possess substantial chemopreventive properties. An example is curcumin (Curcuma longa Linn., Zingiberaceae), which has been shown to inhibit tumor promotion in experimental carcinogenesis. Alpinia oxyphylla Miquel, another plant of the ginger family used in oriental herbal medicine, contains diarylheptanoids whose structures are analogous to that of curcumin. In the present study, we have tested A.oxyphylla for its ability to suppress tumor promotion. Thus, topical application of the methanolic extract of dried fruits of A.oxyphylla significantly ameliorated 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin tumor promotion as well as ear edema in female ICR mice. In another study, treatment of HL-60 cells with the methanolic extract of A.oxyphylla significantly reduced the viability of the cells and also inhibited DNA synthesis. Microscopic examination of the treated cells showed characteristic morphology of apoptosis. Furthermore, cells treated with the extract of A.oxyphylla exhibited internucleosomal DNA fragmentation in time- and concentration-dependent manners. TPA-stimulated generation of superoxide anion in differentiated HL-60 cells was also blunted by A.oxyphylla. Taken together, these findings suggest that A.oxyphylla possesses potential chemopreventive and antitumorigenic activities.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Calcitonin gene-related peptide protects cultured rat gastric mucosal cells.

Capsaicin exerts its gastroprotective effect by stimulating primary afferent neurons, releasing calcitonin gene-related peptide (CGRP), which in turn increases gastric blood flow. In this work, the effects of capsaicin, rat alpha-CGRP, and relative peptides hCGRP(8-37) and beta-hCGRP, and substance P on cultured gastric mucosal cells independent of neural and vascular mechanisms were studied. Damage was produced by indomethacin, ethanol or taurocholate 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and trypan blue exclusion tests were used to assess viability of the cultured cells. Capsaicin administration alone did not injure gastric cells. However, capsaicin pretreatment potentiated the damaging effect of indomethacin and ethanol. In the sodium taurocholate model, capsaicin slightly protected the cells against injury. Alpha-rCGRP was protective against indomethacin, ethanol and taurocholate in a dose-dependent manner. hCGRP(8-37) and beta-hCGRP both dose-dependently prevented injury caused by indomethacin at concentrations about eight times higher than that of alpha-rCGRP, but substance P was ineffective in the three different damage models. A combination of alpha-CGRP and hCGRP(8-37) was also protective against indomethacin damage to a similar extent as use of either agent alone. The defence mechanism of capsaicin against gastric cell injury may in part be mediated by a direct effect of CGRP on gastric mucosal cells, in addition to effects dependent on neural and vascular mechanisms. hCGRP(8-37) has no antagonist effect against CGRP in this model, suggesting that CGRP receptors in this model may be different from those in other tissues.

Animals↗
PubMed1998

Validation of [13C]urea breath test for Helicobacter pylori using a simple gas chromatograph-mass selective detector.

OBJECTIVE: Isotope ratio mass spectrometry (IRMS) is the accepted method for accurately measuring the 13CO2:12CO2 ratio in the non-invasive and non-radioactive [13C]urea breath test (13C-UBT) for Helicobactor pylori. The IRMS instrument, an expensive and highly specialized analyser, is rarely available. The objective of this project was to modify and validate the use of a simple bench-top gas chromatograph-mass selective detector (GC-MSD) for 13C-UBT. METHODS: Breath samples from 71 patients were taken at baseline and 30 min after ingestion of 100 mg [13C]urea. The breath samples were analysed using GC-MSD in the selected ion monitoring mode. The reference 13CO2:12CO2 ratio was from NBS19 obtained from the US National Institute of Standards and Technology. 13CO2:12CO2 ratios of the breath samples were determined. Excess delta per thousand (per mil, delta/thousand) of the 30 min sample over the baseline (deltadelta/thousand) of > or = 6deltadelta/thousand was considered H. pylori positive. Results from 13C-UBT and histology determined blind to each other were compared. RESULTS: The coefficient of variation of the reference 13CO2:12CO2 ratio was 0.06%. Using histology as the 'gold standard', the sensitivity (97.9%) and specificity (95.8%) of the GC-MSD 13C-UBT were comparable to those of other methods of H. pylori diagnosis. CONCLUSION: A gas chromatograph coupled to a mass selective detector that is available in many analytical and biomedical laboratories can be used for the 13C-UBT. This method will increase the availability and reduce the cost of this non-invasive, non-radioactive diagnostic test.

Breath Tests↗
PubMed1998

Protective action of capsaicin and chilli on haemorrhagic shock-induced gastric mucosal injury in the rat.

Chilli and its pungent ingredient, capsaicin, have been shown to protect against experimental gastric mucosal injury induced by various necrotizing agents such as ethanol and aspirin and stress. We investigated the effect of capsaicin and long-term ingestion of chilli on haemorrhagic shock-induced gastric mucosal injury in the rat. Anaesthetized male Sprague-Dawley rats were subjected to haemorrhagic shock by withdrawing blood to reduce the mean arterial blood pressure to 30-40 mmHg with subsequent reinfusion of shed blood. This resulted in gastric mucosal injury with readily identifiable haemorrhagic lesions. Capsaicin (5 mg) administered prior to, but not after, haemorrhagic shock, significantly reduced the gastric mucosal injury in intact animals. Sensory ablation with capsaicin pretreatment (125 mg/kg bodyweight) abolished the gastroprotective effect afforded by capsaicin. Similarly, 4 week intake of chilli powder (360 mg daily) reduced the gastric mucosal injury in intact, but not in capsaicin-desensitized rats. Capsaicin and long-term chilli intake protected against haemorrhagic shock-induced gastric mucosal injury and the protection may be mediated by capsaicin-sensitive afferent neurons. Our studies are of potential significance in the context of stress ulcer disease in the human.

Animals↗
PubMed1998

Symptomatic gastro-oesophageal reflux in pregnancy: a prospective study among Singaporean women.

The present study was undertaken to estimate the prevalence and time course of reflux-type symptoms in Singaporean women and to determine if these symptoms were associated with nausea and vomiting of pregnancy. Consecutive pregnant women in the first trimester of pregnancy were recruited during attendance at an antenatal clinic in a Singapore teaching hospital. Each was interviewed, using a reliable questionnaire detailing demographic characteristics and symptoms, at four time points during the first, second and third trimesters of pregnancy and postpartum period. A total of 35 of 47 women originally enrolled (response rate 74%) completed the study. Heartburn alone, acid regurgitation alone and both heartburn and acid regurgitation were reported by 5.7, 17.1 and 17.1% of the subjects, respectively. Subjects who had these symptoms were more likely to suffer daily nausea and/or vomiting (78.6%) than those who did not (33.3%, P<0.05). In the majority of subjects, heartburn and/or acid regurgitation began in the first trimester (78.6%) and disappeared during the second trimester (71.4%). Nausea alone and in combination with vomiting similarly came on in the first trimester (100%) and subsided by the second trimester (85.7%) in the majority of the subjects studied. The reported prevalence of heartburn and/or acid regurgitation among Western pregnant women were 48-96% and 62%, respectively. Our data, therefore, showed that reflux-type symptoms were less common in Singaporean pregnant women. Reflux-type symptoms were related to nausea and vomiting, both in frequency and time pattern of onset and disappearance of symptoms. The association suggested either a common mechanism or a cause and effect relationship.

Adult↗
PubMed1998

The effect of test duration on the sensitivity and specificity of ultra-rapid urease test for the detection of Helicobacter pylori infection.

BACKGROUND: 'Home made' ultra-rapid urease tests are used extensively in the Asia Pacific region. Data on the reliability of these 'home made' tests are limited. AIMS: To evaluate the effect of test duration on the sensitivity and specificity of a self-prepared biopsy urease test for the detection of Helicobacter pylori. METHODS: Using histology as the 'gold standard', the effect of test duration on the sensitivity and specificity of a self prepared urease test for the detection of H. pylori was evaluated in 411 consecutive patients undergoing upper gastrointestinal endoscopy. RESULTS: Histology was positive for H. pylori in 217 of the 411 patients (52.8%). Within 24 hours of retrieving the specimen, 189 (87.1%) of the histology positives and 174 (89.7%) of the histology negatives were correctly identified by the urease test. Of the H. pylori positives, 72.0%, 81.0%, 89.9% and 100% were detected by the urease test within one minute, five minutes, three hours and 24 hours respectively. Thus, sensitivities of the urease test at one minute, five minutes, three hours and 24 hours were 62.7%, 70.5%, 78.3% and 87.1% respectively. Corresponding figures for the specificity were 93.8%, 93.3%, 92.3% and 89.7% respectively. Using a receiver-operating characteristic curve, an optimal combination of sensitivity and specificity was obtained when the urease test was read at 24 hours. CONCLUSIONS: While the biopsy urease test was positive in most cases within a minute, better results could be obtained if the test continued to be read over a 24 hour period.

Adolescent↗
PubMed1998

Prevalence of gastrointestinal symptoms in a multiracial Asian population, with particular reference to reflux-type symptoms.

OBJECTIVE: Data on the epidemiology of chronic gastrointestinal symptoms in the East are limited. The aims of this study were to estimate the prevalence of chronic gastrointestinal symptoms in Singapore and to determine whether ethnic differences in the prevalence of these symptoms exist. METHODS: A cross-sectional survey, using a reliable and valid questionnaire, was carried out in a race-stratified random sample of residents aged 21-95 yr (mean+/-SD, 40+/-1 yr) in a Singaporean town; 93% responded (n=696). RESULTS: The ethnic-adjusted prevalence of chronic abdominal pain, frequent dyspepsia, irritable bowel syndrome, chronic constipation, chronic diarrhea, and frequent reflux were 5.7% (95% confidence interval [CI], 3.3-8.1), 7.9% (95% CI, 5.0-10.8), 2.3% (95% CI, 0.8-3.9), 3.9% (95% CI, 1.9-5.9), 4.5% (95% CI, 2.3-6.7), and 1.6% (95% CI, 0.6-2.6), respectively. There were no ethnic differences in the prevalence of any of these symptom categories except for reflux-type symptoms, which were more common among Indians (7.5%; 95% CI, 4.4-11.7) than Chinese (0.8%; 95% CI, 0.1-3.0) or Malays (3.0%; 95% CI, 1.26.1). CONCLUSION: The prevalence of all types of chronic gastrointestinal symptoms in the general population of Singapore was low compared with those in the West. Chronic gastrointestinal symptoms were equally prevalent in the three major ethnic groups except for reflux-type symptoms, which were more common among Indians than Chinese or Malays.

Abdominal Pain↗
PubMed1998

Role of capsaicin sensitive nerves in epidermal growth factor effects on gastric mucosal injury and blood flow.

BACKGROUND: Epidermal growth factor (EGF) and capsaicin protect against experimental gastric mucosal injury. Capsaicin exerts its gastroprotective effect by stimulating afferent neurones leading to release of calcitonin gene related peptide (CGRP) which causes gastric hyperaemia. EGF also causes gastric hyperaemia but whether it acts via capsaicin sensitive neurones is unknown. AIMS: To assess the influence of: (1) capsaicin desensitisation on EGF effects on gastric mucosal injury and gastric mucosal blood flow: and (2) close arterial infusion of hCGRP8-379, a CGRP antagonist, on EGF effects on gastric mucosal blood flow. METHODS: The absolute ethanol induced gastric mucosal injury model in the rat was used. Gastric mucosal damage was assessed by planimetry and light microscopy. Gastric mucosal blood flow was measured by laser Doppler flowmetry in a gastric chamber preparation. RESULTS: Capsaicin desensitisation abolished the gastroprotective and gastric hyperaemic effects of EGF. Close arterial infusion of hCGRP8-37 antagonised the hyperaemic effect of both capsaicin and EGF. CONCLUSION: Results show that EGF may exert its gastroprotective and gastric hyperaemic effects via capsaicin sensitive afferent neurones.

Animals↗
PubMed1998

Non-cardiac, non-oesophageal chest pain: the relevance of psychological factors.

BACKGROUND: No cause has been determined for chest pain that is neither cardiac nor oesophageal in origin. AIMS: To compare the prevalence of life-time psychiatric disorders and current psychological distress in three consecutive series of patients with chronic chest or abdominal pain. PATIENTS: Thirty nine patients with non-cardiac chest pain and no abnormality on oesophagogastroduodenoscopy, oesophageal manometry, and 24 hour pH monitoring; 22 patients with non-cardiac chest pain having endoscopic abnormality, oesophageal dysmotility, and/or pathological reflux; and 36 patients with biliary colic. METHODS: The Diagnostic Interview Schedule and the 28 item General Health Questionnaire were administered to all patients. RESULTS: Patients with non-cardiac chest pain and no upper gastrointestinal disease had a higher proportion of panic disorder (15%), obsessive-compulsive disorder (21%), and major depressive episodes (28%) than patients with gallstone disease (0%, p < 0.02; 3%, p < 0.02; and 8%, p < 0.05, respectively). In contrast, there were no differences between patients with non-cardiac chest pain and upper gastrointestinal disease and patients with gallstone disease in any of the DSM-111 defined lifetime psychiatric diagnoses. Using the General Health Questionnaire, 49% of patients with non-cardiac chest pain without upper gastrointestinal disease scored above the cut off point (that is, more than 4), which was considered indicative of non-psychotic psychiatric disturbance, whereas only 14% of patients with gallstones did so (p < 0.005). The proportions of such cases were however similar between patients with non-cardiac chest pain and upper gastrointestinal disease (27%) and patients with gallstones. CONCLUSIONS: Psychological factors may play a role in the pathogenesis of chest pain that is neither cardiac nor oesophagogastric in origin.

Adult↗
PubMed1997

Effect of cisapride on functional dyspepsia in patients with and without histological gastritis: a double-blind placebo-controlled trial.

In the present double-blind placebo-controlled study the effect of cisapride on functional dyspepsia was evaluated in patients with and without histological gastritis. Patients with functional dyspepsia and whose symptoms persisted after a 2 week run-in period with antacid treatment were randomized to receive cisapride (10 mg) or matching placebo three times daily for 4 weeks. Symptoms of epigastric pain, bloating, nausea, belching, early satiety and heartburn were graded on a four-point scale based on patients' feedback and diary card recording. A global response was also formulated by the investigators. One hundred and four patients entered the study and 76 completed the trial, comprising 36 patients with histological gastritis and 40 patients without gastritis. Symptom scores in both gastritis and non-gastritis groups were significantly improved by both cisapride and placebo; however, the improvement was not statistically different between the two treatment groups. Cisapride produced a good or better global response in 58% of subjects with histological gastritis and in 53% of subjects without gastritis compared with 47% and 52%, respectively, of patients on placebo; this difference was not statistically significant. Gastric histology did not influence the effect of cisapride on the symptoms of functional dyspepsia.

Adult↗
PubMed1997

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency.

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Adolescent↗
PubMed1997

Tropical liver abscess.

Forty-one consecutive cases of liver abscesses seen at the National University Hospital, Singapore from 1988 to 1994 were reviewed. Twenty-seven cases (65%) were pyogenic, six (15%) amoebic, two (5%) tuberculous and six (15%) indeterminate. The predominance of pyogenic abscesses is in marked contrast to previous studies from the region a decade ago in which amoebic abscesses were the commonest type. The commonest pathogen causing pyogenic abscess was Klebsiella pneumoniae. Two cases were due to Mycobacterium tuberculosis, and this organism needs to be actively looked for in smears and cultures of aspirated material. As the majority of organisms isolated were resistant to ampicillin, empirical antibiotic treatment for suspected pyogenic abscess should include gentamicin or a cephalosporin. Percutaneous needle aspiration of the abscess was performed for 85% of pyogenic abscesses and surgery was necessary in only two cases because of complications. We found that percutaneous aspiration of liver abscess is helpful to confirm the diagnosis, provides a better bacteriological culture yield, gives a good outcome, and may uncover clinically unsuspected conditions like malignancy and tuberculoma which may mimic the presentation of liver abscesses. We recommend routine cytological examination of aspirated abscess material as well as stains and cultures for acid-fast bacilli.

Adult↗
PubMed1996

Subcutaneously administered recombinant human beta-interferon in the treatment of chronic hepatitis B virus infection.

BACKGROUND: Treatment of chronic replicative hepatitis B virus (HBV) infection is aimed at stopping viral replication and preventing the development of chronic liver disease. beta-Interferon treatment has been less well studied than alpha-interferon. METHODS: The efficacy and tolerability of a 6-month course of subcutaneously administered human recombinant beta-interferon (rINF-beta ser) was studied and the results of a low-dose regime compared with a high-dose regime. Twenty patients (17 men and three women), aged 24-54 years, with chronic hepatitis B virus infection (all hepatitis B surface antigen-positive with detectable HBV-DNA in their sera for at least 3 months prior to therapy) were randomized into two treatment groups of 10 patients each. The low-dose group received 6 x 10(6) U/dose and the high-dose group received 30 x 10(6) U/dose, both groups receiving their respective doses three times a week initially for 1 month and continuing for a total of 6 months. RESULTS: The treatment was well tolerated in both groups. None of the patients required dosage reduction or cessation of treatment because of side-effects. HBV-DNA decreased in all patients during treatment, demonstrating the anti-viral efficacy of rINF-beta ser, and was undetectable in 20 and 40% of patients receiving low-dose and high-dose regimes, respectively, at the end of 6 months treatment (P = N.S.). One year after completion of treatment, HBV-DNA was undetectable in 50 and 30% of patients in the low-dose and high-dose groups, respectively (P = N.S.). However, only one patient achieved seroconversion with loss of the hepatitis B surface antigen and appearance of an antihepatitis B 'e' antigen at the end of 18 months. CONCLUSION: This study shows that subcutaneously administered rINF-beta ser is well tolerated, but the optimal dose and duration of treatment still needs to be defined by further studies.

Adult↗
PubMed1996

Chronic upper abdominal pain due to duodenal ulcer and other structural and functional causes: its localization and nocturnal occurrence.

The aim of the present study was to determine the degree of pain localization and frequency of nocturnal pain in duodenal ulcer and other causes of chronic upper abdominal pain. These parameters were prospectively recorded in a consecutive series of 1615 patients with chronic upper abdominal pain presenting to one gastroenterologist. The proportion of patients who were able to localize the site of their pain using a single finger was 13% for duodenal ulcer, 5% for gastric ulcer, 17% for biliary disease, 7% for functional dyspepsia and 8% for irritable bowel syndrome. The numbers of subjects with the above diagnoses who experienced nocturnal pain were 63, 63, 51, 41 and 58%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for duodenal ulcer were 13, 92, 14 and 91%, respectively, for localized pain; 63, 50, 11 and 93%, respectively, for nocturnal pain occurrence; and 9, 96, 20 and 90%, respectively, if the pain was both localized and nocturnal. If the pain was neither localized nor nocturnal, the corresponding values for the absence of duodenal ulcer disease were 49, 68, 93 and 13%, respectively. The pain of duodenal ulcer was therefore more likely to be nocturnal and well localized compared with pain from other causes. However, while the absence of these features made duodenal ulcer unlikely, their presence was less helpful in the diagnostic process.

Abdominal Pain↗
PubMed1996

Effect of capsaicin and cimetidine on the healing of acetic acid induced gastric ulceration in the rat.

BACKGROUND: Capsaicin protects the gastric mucosa against experimental injury while capsaicin desensitisation reduces the rate of gastric ulcer healing. The effect of exogenous capsaicin on gastric ulcer healing has not to date been reported. AIM/METHOD: To investigate the effect of capsaicin, cimetidine, and in combination, given intragastrically in the healing of acetic acid induced chronic gastric ulcer in the rat. Treatment started immediately after ulcer induction. RESULTS: At the end of one week, capsaicin, cimetidine, and in combination increased ulcer healing but the effect of combined treatment was less than that of capsaicin alone. In an in vivo gastric chamber preparation, capsaicin increased, while cimetidine decreased, gastric mucosal blood flow measured by laser Doppler flowmetry. A dose response effect in reduction of gastric mucosal blood flow could be demonstrated for cimetidine. The gastric hyperaemic effect of capsaicin was blunted by prior administration of cimetidine. In contrast, capsaicin had no effect on gastric acid secretion and its addition to cimetidine did not affect the acid suppressant effect of the latter. CONCLUSIONS: Capsaicin promotes the healing of acetic acid induced gastric ulcer, probably by its gastric hyperaemic effect. Although cimetidine also promotes ulcer healing due to its inhibitory effect on acid secretion it may have an antagonistic effect on the gastric ulcer healing effect of capsaicin by virtue of inhibition of gastric hyperaemia.

Acetic Acid↗