Biomedical subjects
Publications and source records attributed to I Yap.
A case of cholestatic jaundice following treatment with Augmentin is reported. The awareness of hepatotoxicity due to drug should help to avoid unnecessary invasive procedures in the evaluation of this reversible condition.
We describe nine cases of esophageal injury associated with the ingestion of prescribed medications. Antibiotics were the most commonly implicated drugs. Odynophagia, retrosternal chest pain and dysphagia were the usual presenting symptoms. The typical endoscopic finding was that of discrete ulcers in the mid-esophagus. All patients recovered uneventfully with discontinuation of the offending drug and symptomatic treatment. Drug induced esophageal injury should be considered in patients presenting acutely with the above mentioned symptoms and having discrete esophageal ulcers on endoscopy.
A 54-year-old man who presented with marked hepatomegaly and a liver scan suggestive of an infiltrative malignancy was found to have peliosis hepatis caused by androgenic steroids. A detailed and repeated drug history is necessary for making the correct diagnosis. Withdrawal of the offending drug is indicated and may result in reversal of this serious form of hepatic toxicity.
A novel recombinant hepatitis B vaccine, trademarked Sci-B-Vac, was evaluated for safety, tolerability and immunogenicity in an open label trial performed in Singapore. The experimental vaccine, derived from Chinese hamster ovary (CHO) cells, consists of hepatitis B surface antigen (HBsAg) particles harbouring all three viral envelope polypeptides, the major S protein and the minor Pre-S2 and Pre-S1, in their glycosylated and non-glycosylated forms. The vaccine was administered intramuscularly at 0, 1 and 6 months. No unexpected adverse effects were observed. A high level anti-HBs response to Sci-B-Vac was indicative of its immunogenicity. Subsequent to the third injection, 100% and 92% of the 10 micrograms and 5 micrograms dose recipients, respectively, were seroprotected (anti-HBs titres greater than or equal to 10 mIU ml-1). Moreover, the geometric mean titres (GMT) of the anti-HBs response were very high: 2687 and 1473 mIU ml-1, respectively. An immunogenic advantage of Sci-B-Vac was also suggested by the rapid onset of antibody response: 96% of the 10 micrograms dose recipients were seroprotected with a GMT of 159 mIU ml-1, prior to the third injection.
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We have shown previously that acid is one factor, although not the only one, in the pathogenesis of duodenal ulcer pain. In the present study patients with gastric ulcer were endoscoped without sedation or premedication. Under direct vision the ulcer craters were infused sequentially with 0.1 N HCl and normal saline, the sequence of infusion being randomized and double blind. Typical ulcer pain occurred in seven of 19 patients during acid infusion compared with one with saline (p = 0.023). Two patients who developed pain on acid were rechallenged after their pain disappeared, and typical pain recurred in both. Acid therefore has a definite role in the pathogenesis of gastric ulcer pain.
One hundred and six fine needle aspiration biopsies (FNAB) of the liver were performed on 99 patients to rule out hepatic malignancy. Biopsies were performed with CT guidance (60), ultrasonography (40), fluoroscopy (3), by direct palpation (2) and intra-operatively (1). The smears and cell blocks were reviewed and the cytologic diagnoses were made after clinicopathologic correlation. Eight cases were excluded (six non-diagnostic and two mislaid). Fifty-two were positive, 2 suspicious and 44 negative for malignancy. There were no false positive results. The sensitivity for malignancy was 84.4%, the specificity was 100% and the predictive value of positive results was 100%. The false negative rate was ten out of 44 cases (22.7%). Of the malignant aspirates, there were 27 hepatocellular carcinomas, 21 metastases and four carcinomas of unknown histogenesis. Common benign lesions included abscesses, cysts, cirrhosis and steatosis. For FNAB to be an effective diagnostic procedure, adequate representative sampling, cell block preparation for appraisal of histological architecture and experience in cytomorphologic interpretation are necessary to increase yield and enhance precision of diagnosis.
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.
Three hundred and sixty one consecutive barium enemas done at a general hospital were reviewed prospectively to determine the frequency and anatomic distribution of diverticulosis in Singapore. The frequency of 28% is comparable to previous American and European studies and higher than previous Asian studies. There was also a predominance of purely right-sided disease with the caecum and/or ascending colon involved in 71% of patients. This anatomic distribution of diverticulosis is quite different from that seen in Caucasian populations where the disease mainly involves the left side of the colon and is probably a function of genetic and racial factors.
Four hundred and four patients (273 men, 131 women) aged 3 to 85 years with chronic Hepatitis B virus (HBV) infection seen during a five year period were analysed. At presentation, 177 patients (44%) were Hepatitis B e Antigen (HBeAg) positive (mean age 32 years) and 217 patients (54%) were anti-HBe-positive (mean age 40 years). Ten patients (2%) were negative for HBeAg and anti-HBe. Serum HBV-DNA was detected in 169 patients (42%). 85% of the HBeAg-positive patients had detectable serum HBV-DNA and 9% of the HBeAg-negative patients were positive for serum HBV-DNA. The mean serum Alanine amino-transferase (ALT) and Aspartate amino-transferase (AST) levels were higher in HBeAg-positive patients (75 and 52 iu/l) than in HBeAg negative patients (46 and 37 iu/l) (P less than 0.001). Liver biopsies were performed in 135 patients. Fifty-three (39%) had minimal changes, 61 (45%) chronic hepatitis (CPH, CLH & CAH) and 21 (16%) cirrhosis. There was no significant difference in the histologic distribution between HBeAg-positive and HBeAg-negative groups. Two hundred and fifty eight patients were followed up for a mean duration of 2 years (range 3 to 108 months). The cumulative probability of clearing HBeAg at the end of the first, second and third year were 14%, 16% and 18% respectively. Of these, the cumulative probability of developing anti-HBe over one, two and three years were 8%, 9% and 11% respectively. Reversion to HBeAg occurred in 1.5% of patients who were HBeAg-negative at presentation and 11% of HBeAg-positive patients who cleared HBeAg.(ABSTRACT TRUNCATED AT 250 WORDS)
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)
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%).
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.
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.
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.
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.
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.