Biomedical subjects

H H Tay

Publications and source records attributed to H H Tay.

At least 19 recordsLinked to original sources

PubMed1999

A prospective study of the clinical features, manometric findings, incidence and prevalence of achalasia in Singapore.

BACKGROUND: This study aimed to describe the clinical features, manometric findings, prevalence and incidence of achalasia in Singapore. METHODS: A total of 615 new patients referred for oesophageal manometry between 1989 and 1996 were examined prospectively. Twenty-four men and 25 women fulfilled the manometric and clinical criteria for achalasia. RESULTS: Their median age of onset of symptoms was 37 years (range 15-71) and 37% first developed symptoms after the age of 50 years. The presenting symptoms were dysphagia (100%), regurgitation (80%), weight loss (67%) and chest discomfort (33%). Five patients (10%) had a history of benign (mostly autoimmune) thyroid disorders. Endoscopy was reported as normal in 10/43 patients (23%) and achalasia was suggested in only 31 (72%) of 43 barium examinations. Lower oesophageal sphincter (LOS) dysfunction was present in 82% of cases. Using data from medical records and from a survey of gastroenterologists and surgeons in Singapore, the prevalence (in 1996) and incidence of achalasia in Singapore were estimated to be 1.8 per 100000, and 0.3 per 100000 per year, respectively. The incidence was significantly lower in Malays than Chinese or Indians. The age-specific incidence of achalasia for both genders followed a bimodal distribution with the larger peak in the sixth decade. No cases of oesophageal carcinoma were identified among these patients. CONCLUSION: Achalasia is an uncommon condition in Singapore. The clinical and manometric features were similar to those described in Western countries.

Adolescent↗

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↗

PubMed1996

Primary biliary cirrhosis--an uncommon disease in Singapore.

Primary biliary cirrhosis (PBC) is uncommon in Singapore. Twelve consecutive patients with PBC were seen between 1987 and 1994 at the National University Hospital. Eleven were women and the mean age at presentation was 53 years. Three patients presented with pruritus and jaundice whilst three had decompensated cirrhosis. The remaining six patients had no symptoms attributed to their liver disease when first detected, three of them presented with associated conditions including sicca syndrome and interstitial lung fibrosis, lichen planus, and carcinoma of breast. All patients had elevated serum alkaline phosphatase and positive anti-mitochondrial antibodies. Liver histology (10/12) showed Stage II disease (2), Stage III (5) and Stage IV (3). Three patients also had co-existing gall bladder stones but their endoscopic retrograde cholangiograms were normal. The mean follow-up period was 32.6 months and four patients died during follow-up. The only male patient had liver transplantation, two patients had symptomatic treatment while the rest were treated with ursodeoxycholic acid. In conclusion, local patients tended to presented relatively early in the course of the disease with 50% being asymptomatic and in the precirrhotic Stages.

Adult↗

PubMed1995

Seroprevalence of antibodies against hepatitis A (anti-HAV) in Singapore: the NFDD experience.

At the 4th National Foundation for Digestive Disease (NFDD) Day in 1991 where public lectures on prevention of hepatitis and early detection of hepatocellular carcinoma were given, screening of sera obtained from 364 registrants for antibodies to Hepatitis A (IgG) was undertaken. The overall sero-prevalence rate was 50%, with 55% for males and 46% for females with antibodies for HAV. None of the subjects below 20 years old had antibodies to HAV. This rose to 16% for those 21-30 years old and 92% for those above 61 years. This study shows that in Singapore, prevalence of anti-HAV antibodies rise with age and is approaching the low endemicity pattern that is seen in developed countries.

Adolescent↗

PubMed1993

Low frequency of endoscopic esophagitis in Asian patients.

The aim of this study was to determine the frequency of endoscopic esophagitis in patients seen for upper gastrointestinal complaints in an Asian center. We studied a consecutive series of 11,943 patients undergoing diagnostic esophagogastroduodenoscopy at our unit over a 10-year period. Three hundred and eighty-nine patients (3.3%) had endoscopic esophagitis with no other significant lesion (primary esophagitis), whereas 143 (1.2%) had esophagitis associated with peptic ulcer or gastric or duodenal malignancy (secondary esophagitis). In contrast, peptic ulcer was diagnosed in 2,787 patients (23.3%) and gastric carcinoma in 286 (2.4%). The reported frequency of endoscopic esophagitis among patients undergoing endoscopy in Western countries varied from 9 to 23%. Our data therefore show that endoscopic esophagitis is much less common in Singaporean patients.

Adult↗

PubMed1992

Chronic upper abdominal pain: site and radiation in various structural and functional disorders and the effect of various foods.

Pain site and radiation and the effect of various foods were studied prospectively in a consecutive series of patients with chronic upper abdominal pain. Patients followed for less than one year were excluded unless peptic ulcer or abdominal malignancy had been diagnosed or laparotomy had been carried out. A total of 632 patients were eligible for the first study and 431 for the second. Gastric ulcer pain was more likely to be left hypochondrial (17%) compared with pain from duodenal ulcer (4%) or from all other conditions (5%). It was less likely to be epigastric (54%) compared with duodenal ulcer pain (75%). Oesophageal pain was more likely to be both retrosternal and epigastric (25%) compared with non-oesophageal pain (2%). Radiation to the back was more common in peptic ulcer (31%) and biliary pain (35%) compared with functional pain (20%). Pain precipitation by fatty foods was commoner in biliary disease (40%) than in duodenal ulcer (11%), peptic ulcer (9%), or non-ulcer dyspepsia (19%). Orange, alcohol, and coffee precipitated pain more frequently in duodenal ulcer (41%, 50%, and 43% respectively) than in biliary disease (17%, 0%, and 14% respectively). Chilli precipitated pain in one quarter to one half of subjects regardless of diagnosis. Approximately one tenth of all subjects avoided chilli, curry, coffee, and tea because of medical or other advice.

Abdominal Pain↗

PubMed1991

Seroprevalence of antibodies to the hepatitis C virus in Singapore.

The prevalence of antibodies to the hepatitis C virus (anti-HCV) in Singapore was assessed using a recombinant-based enzyme linked immunoassay system. 1004 serum samples were obtained from normal subjects (463), hemodialysis patients (112), hepatitis B virus (HBV) carriers (188), patients with hepatocellular carcinoma (HCC) (58) and patients with non-hepatitis B virus related liver diseases (183). Anti-HCV was found to be positive in 1.7% of healthy subjects, and in 20% of patients on regular hemodialysis. Three percent of HBV carriers were positive for anti-HCV. Twelve percent of patients with acute hepatitis with no known causes and 20% patients with chronic hepatitis with no known causes were positive for anti-HCV. Among patients with cirrhosis for which no known causes were found 33% were positive for anti-HCV. Thirty six percent of patients with HCC not associated with the presence of HBsAg were positive of anti-HCV. None of the patients with known causes of liver disease were positive for anti-HCV.

Adolescent↗

PubMed1991

The diagnostic yield of upper gastrointestinal endoscopy in the investigation of anaemia.

Computer records of patients endoscoped over a 34-month period were studied to assess the diagnostic yield of gastrointestinal endoscopy in patients with anaemia. Patients with obvious gastrointestinal bleeding and known gastrointestinal pathology were excluded. On hundred and thirty-six patients were endoscoped for anaemia. Eighty-three of them (61%) had iron deficiency anaemia and 53 (39%) had other types of anaemia. The ages of the patients with iron deficiency anaemia (mean 56 years) were significantly lower than those of other anaemias (means 65 years), (p less than 0.003). Patient characteristics were otherwise comparable. There were significant endoscopic findings (ulcers, carcinoma and haemorrhagic or erosive gastritis) in 26 of 83 patients (31%) with iron deficiency anaemia, in 11 of 53 patients with other anaemias (21%) and 37 of 136 patients (27%) combined. Significant endoscopic findings were found in 506 of 2224 patients (23%) endoscoped during this period who were not anaemic, did not have obvious gastrointestinal haemorrhage and were not known to have gastrointestinal diseases. The diagnostic yield for iron deficiency anaemia was significantly higher than for the non anaemic group (p less than 0.05). There was no difference between the diagnostic yields of iron deficiency and other anaemias, other anaemias and the non anaemic group, or total anaemias and the non anaemic group. Gastrointestinal symptoms and history of analgesic or steroid usage did not appear to increase the incidence of gastrointestinal lesions in either iron deficiency anaemia or other anaemias. Twenty-three of 41 patients (56%) who had no cause for anaemia found at the end of all investigations were colonscoped.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

The site of recurrent duodenal ulcer.

The aim of this retrospective study was to determine the site of recurrent duodenal ulcer in relation to the site of the index ulcer. One hundred and thirty-five patients who had recurrent duodenal ulcer after documented healing of an index ulcer were studied. The recurrent ulcer was more likely to occur in the anterior bulb if the index ulcer was anterior (35 of 58 = 60%) than if the index ulcer was not anterior (29 of 77 = 38%, p less than 0.01). However, the likelihood of a recurrent ulcer on the posterior wall of the bulb was not significantly different whether the index ulcer was posterior (11 of 36 = 31%) or not (22 of 99 = 22%, p less than 0.24). Three of 20 patients (15%) who initially presented with bleeding bled again with their recurrent ulcers, compared with eight of 115 patients (7%) who first presented with dyspepsia only (p = 0.39). Thirteen patients were assessed independently by two endoscopists to determine ulcer site. Their assessments concurred for 12 (92%).

Adolescent↗

PubMed1990

The influence of dialect group on peptic ulcer frequency amongst the Chinese in Singapore.

In Singapore, peptic ulcer is more common amongst Chinese than amongst Malays or Indians. Earlier work has suggested that, amongst female Chinese, Cantonese women are more susceptible to ulcer disease when compared to females of other dialect groups. The aim of the present study was to confirm or refute this possibility. The dialect group distribution of 897 Chinese patients with peptic ulcer (duodenal ulcer 601, gastric ulcer 296) was compared with that of non-ulcer dyspepsia patients and 1602 general medical patients attending the same medical units. The proportion of various dialect groups (including Cantonese) was similar in all patient groups. The proportion of ulcer patients presenting with haemorrhage was also similar in the different dialect groups. We conclude that no major dialect differences exist in peptic ulcer frequency amongst the Chinese in Singapore.

China↗

PubMed1990

Effect of colloidal bismuth subcitrate on symptoms and gastric histology in non-ulcer dyspepsia. A double blind placebo controlled study.

The aim of this study was to determine the effect of colloidal bismuth subcitrate (De Nol) on symptoms and gastric histology in patients with non-ulcer dyspepsia. In a single centre trial, patients with food related upper abdominal pain not caused by ulcer disease were randomised to receive one tablet of colloidal bismuth subcitrate or matching placebo four times daily for eight weeks. Seventy three patients were entered and 51 completed the trial: 28 patients in the colloidal bismuth subcitrate group and 23 in the placebo group. Overall there was no difference between the two groups in terms of symptom relief. Among patients with histological gastritis (n = 23), however, those who took colloidal bismuth subcitrate used fewer antacid tablets (for three of four fortnightly periods) and were more likely to become asymptomatic (eight of 11 v three of 12, p less than 0.05); their gastritis was more likely to resolve (five of 10 v 0 of 12, p less than 0.025) and their gastric biopsies more likely to become negative for Helicobacter like organisms (eight of nine v 0 of 12, p less than 0.001) when compared with patients taking placebo. In contrast, patients who did not have gastritis in their index biopsies (n = 28) fared similarly whether they received colloidal bismuth subcitrate or placebo. Our results indicate that the administration of colloidal bismuth subcitrate benefited non-ulcer dyspepsia patients with gastritis but had no effect on those without.

Adult↗

PubMed1990

Helicobacter pylori and gastritis in patients with peptic ulcer and non-ulcer dyspepsia: ethnic differences in Singapore.

Peptic ulcer occurs with different frequencies in the three main racial groups in Singapore. This study aimed firstly to determine the prevalence of Helicobacter pylori in peptic ulcer and non-ulcer dyspepsia patients of the different races and secondly, to assess the relation between H pylori, histological gastritis, patient diagnosis, and race. Gastric antral biopsy specimens from 1502 patients undergoing gastroduodenoscopy were studied and 892 (59%) were positive for H pylori. H pylori was strongly associated with gastritis: 873 of 1197 (73%) patients with gastritis were positive compared with 19 of 305 (6%) without gastritis (p less than 0.0001). The prevalences of H pylori and gastritis were similar in peptic ulcer patients of different races. Malay patients with non-ulcer dyspepsia, however, were less likely to be positive for H pylori (10 of 46 (22%] or to have antral gastritis (17 of 46 (37%] than Chinese (292 of 605 (48%) were positive for H pylori and 421 of 605 (70%) had gastritis) and Indians (35 of 61 (57%) were H pylori positive and 42 of 61 (69%) had gastritis). Patients with duodenal ulcer were more likely to be positive for H pylori than those with non-ulcer dyspepsia, even when subjects with gastritis were considered separately. While our results do not help to explain the observed racial differences in peptic ulcer frequency it may be that the pathophysiology of non-ulcer dyspepsia is different in the different races in Singapore.

Adult↗

PubMed1990

Comparison of culture and histology for the identification of Helicobacter pylori in endoscopic biopsies.

The aim of the study was to compare culture with microscopic examination of haematoxylin and eosin stained tissue sections in the identification of Helicobacter pylori in gastric antral mucosa. Duplicate gastric antral biopsies from 89 patients were cultured and examined histologically for H pylori. H pylori was cultured in 46 cases (51%) and identified histologically in 63 (71%). Results from the two tests concurred in 63 cases (71%). The presence of H pylori was strongly correlated with histological gastritis. Microscopic examination of haematoxylin and eosin stained tissue sections is therefore a reliable and convenient method of identifying H pylori.

Campylobacter↗

PubMed1990

Multiple endocrine neoplasia type 1--presenting with impotence.

A 35-year old man presented with a 4-year history of impotence. His past history was significant for hypercalcaemia, bilateral pyelolithotomies for renal calculi and parathyroidectomy for hyperparathyroidism. He had an episode of haemetemesis and malaena a year before being seen here. Endocrine investigations revealed hyperprolactinemia, hypergastrinemia and increased basal acid output. Magnetic resonance imaging of the brain was indicative of a pituitary microadenoma. Computed tomographic scan of the abdomen revealed a bulky pancreas which was suggestive of a gastrin-secreting islet cell tumour. This case illustrates an unusual presentation of multiple endocrine neoplasia type 1 (MEN-1) with impotence and hyperprolactinemia. A short review of the literature was done.

Adenoma↗

PubMed1990

Hepatitis B vaccination in chronic renal failure patients undergoing haemodialysis: the immunogenicity of an increased dose of a recombinant DNA hepatitis B vaccine.

Thirty-two patients with end stage renal failure who were on haemodialysis and who had no previous exposure to hepatitis B virus were given four intramuscular injections of 40 micrograms (twice the recommended dose) recombinant DNA hepatitis B vaccine (Engerix B, Smith Kline Biologicals) at 0, 1, 2 and 6 months to determine the immunogenicity of this increased vaccine dose. The ages of these patients ranged from 23-54 years with a mean age of 40 years. There were 11 males and 21 females. Three patients underwent renal transplantation during the course of the study and were assessed separately. Antibody levels above 10 IU/L were noticed in 83% of the remaining 29 patients two months after the final dose with an anti-HBs geometric mean titre (GMT) of 2551 IU/L. The antibody response was 82% four months later although the GMT has fallen to 664 IU/L. Renal transplantation did not appear to affect the anti-HBs response to the above vaccination regime. None of the volunteers developed hepatitis B during the study. Our results were much better than results obtained in studies using twice the recommended doses given three times.

Adult↗

PubMed1989

Acid induced duodenal ulcer pain: the influence of symptom status and the effect of an antispasmodic.

The aims of this study were to determine whether the development of acid induced duodenal ulcer pain was influenced by the symptomatic status of the patient and whether the administration of an antispasmodic could abolish pain. One hundred millilitres of 0.1 N hydrochloric acid was infused onto the ulcer craters or scars of 143 duodenal ulcer patients on 168 occasions. Symptomatic patients were randomised to receive 40 mg of hyoscine intravenously before acid infusion, or to a control group. Typical ulcer pain developed in seven of 55 (13%) instances for non-symptomatic patients, 24/57 (42%) of control symptomatic patients, and 20/56 (36%) of symptomatic patients given hyoscine. (Asymptomatic group v control symptomatic group, p less than 0.005; control symptomatic group v hyoscine group, NS - 95% confidence limits 12% in favour of the control and 24% in favour of the hyoscine group). The results suggest that acid infusion seldom reproduces ulcer pain in non-symptomatic duodenal ulcer patients and that the pathogenesis of acid induced duodenal ulcer pain probably involves a mechanism other than spasm, as pain was not prevented by an anticholinergic.

Adolescent↗

PubMed1989

Immunogenicity of a low dose recombinant DNA hepatitis B vaccine in healthy adults in Singapore.

The immunogenicity and safety of a standard dose of 10 micrograms of a yeast derived recombinant DNA hepatitis B vaccine (B-Hepavac II) was compared with that of a reduced dose of 5 micrograms in 84 healthy adult volunteers with no previous exposure to hepatitis B. Each subject received either a 10 micrograms or 5 micrograms dose of vaccine intramuscularly at 0, 1 and 6 months. One month after the second injection of vaccine the seroconversion rate in the two groups were 85 and 86 percent respectively. Two months after the third injection 100 percent of participants had sero-converted; 95 percent of the 10 micrograms group and 91 percent of the 5 micrograms group had titres of anti-HBs greater than 10 IU/L. The geometric mean titres (GMT) of anti-HBs levels at 2, 6, 8, and 12 months were 34, 61, 811 and 188 IU/L in the 10 micrograms group and 26, 45, 836 and 304 IU/L in the 5 micrograms group respectively. Adverse effects were mild and transient. The vaccine was safe and immunogenic in the doses given. The reduced dose of 5 micrograms was as effective as the standard 10 micrograms dose.

Adolescent↗

PubMed1988

Dietary supplementation with pectin in the maintenance treatment of duodenal ulcer. A controlled study.

Patients with recently healed duodenal ulcers diagnosed by endoscopy were randomly allocated to receive 10 g apple pectin USP powder twice daily, 150 mg ranitidine at night, or one tablet matching ranitidine placebo at night for 6 months. Repeat endoscopy was performed at 6 months or if symptoms recurred. Eighty-three patients completed the study. Recurrences occurred in 23 of 27 (85%) patients taking pectin, 6 of 28 (21%) patients taking ranitidine, and 20 of 28 (71%) patients taking placebo. (Pectin versus placebo, NS; ranitidine versus pectin, p less than 0.00001; ranitidine versus placebo, p less than 0.0005). The average amount of pectin taken was 12.7 g/day in patients who relapsed and 12.4 g/day in those who did not. At the doses taken, therefore, dietary supplementation with pectin did not reduce the incidence of duodenal ulcer relapse.

Adult↗