Biomedical subjects

R Guan

Publications and source records attributed to R Guan.

At least 55 records · Page 3Linked to original sources

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↗

PubMed1995

Immunogenicity and safety of an inactivated hepatitis A vaccine amongst Singaporeans.

The immunogenicity and reactogenicity of an inactivated hepatitis A virus (HAV) vaccine was studied in healthy Singaporean adult volunteers. One hundred and forty healthy volunteers with normal alanine (ALT) and aspartate (AST) transaminases and no previous exposure to HAV, received three 1 ml doses (720 ELISA units) of an inactivated HAV vaccine (Smithkline Beechams Biologicals) following a 0, 1, 6 months vaccination schedule. All subjects were asked to record and grade the severity of any reactions for three consecutive days after each dose. Serum ALT and AST as well as anti-HAV were measured at 0, 1, 2, 6 and 7 months after the first vaccine dose. Anti-HAV seroconversion occurred when levels rose above 40 mIU/ml. Eighty-five percent of vaccinees seroconverted after the first innoculation and 99% after the second injection. All vaccinees seroconverted after the third dose. Geometric mean anti-HAV titers (GMTs) were, respectively, 119, 391, 4406 mIU/ml one month after each of the three doses. The most common side effect was transient pain and tenderness at the vaccination site. No elevation of ALT or AST levels were noted during the study period. The inactivated hepatitis A vaccine used in this study is safe and highly immunogenic in the local adult population. Two doses one month apart appeared to give adequate protection.

Adult↗

PubMed1994

Closure of a benign gastrocolic fistula on medical management.

Gastrocolic fistulae secondary to un-operated benign gastric ulcers are rare. We report a case of a large benign gastrocolic fistula diagnosed by colonoscopy, which was found to have healed over a short period of 3 weeks, while the patient was being prepared for surgery. He was on parenteral nutrition and intravenous cimetidine. The available literature is reviewed and an attempt is made to explain the closure of the fistula on medical treatment. A trial of medical management may be justified in patients with benign gastrocolic fistulae who are poor surgical risks.

Cimetidine↗

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↗

PubMed1993

Transjugular intrahepatic portosystemic shunt: a case report.

Of the various methods currently available to manage potentially life threatening bleeding from oesophagogastric varices, surgical portosystemic shunts are recognised to have the lowest incidence of rebleeding though surgery is associated with high morbidity and mortality. Recently, a promising non-surgical technique has been developed to create an intrahepatic portosystemic shunt via a percutaneous transjugular route. This paper presents a case report of this region's first transjugular intrahepatic portosystemic shunt procedure and briefly reviews the development and preliminary results of this technique.

Catheterization↗

PubMed1993

Pill-induced esophageal ulcer.

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.

Administration, Oral↗

PubMed1993

Hepatitis B virus infection in patients with systemic lupus erythematosus.

Sera from 76 patients with systemic lupus erythematosus (SLE) were examined for HBsAg, anti-HBsAb and total anti-HBcAB by radioimmunoassay. Fifteen patients (19.7%) had one or more of these serological markers of HBV infection. This is comparable to the sero-prevalence in 100 sex- and age-matched healthy individuals (19%). There was no significant difference in the prevalence of HBV infection in patients who had received immunosuppressants compared with those who had not. Patients who had received transfusion of blood or blood products had a higher prevalence of serological markers but this was not statistically significant.

Adolescent↗

PubMed1992

Recombinant DNA hepatitis B vaccine containing Pre-S components of the HBV coat protein--a preliminary study on immunogenicity.

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.

Adolescent↗

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

Cell-mediated immunity in patients on hemodialysis: relationship with hepatitis B carrier status.

We compared cell-mediated immune responses in two groups of patients on hemodialysis. One group of patients were chronic carriers of hepatitis B virus (HBV), and the patients of the other group were HBV antigen negative. Our results show that despite the presence of normal numbers of T cells and an increased CD4/CD8 ratio in both groups of patients compared to healthy controls (p less than 0.0001), only the group of patients who were chronic HBV carriers showed depressed lymphoproliferative responses to phytohemagglutinin (p less than 0.001) and concanavalin A (p less than 0.0001). In contrast, a control group of healthy adult HBV carriers showed normal T cell subsets and lymphoproliferative responses to mitogens, indicating that HBV infection per se did not result in depressed lymphoproliferative responses. These results further substantiate the notion that depressed cell-mediated immunity in chronic renal failure is an important factor in predisposing patients to HBV infection with subsequent development of the chronic carrier state.

Adult↗

PubMed1991

Cytological diagnosis from fine needle aspiration biopsy of the liver.

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.

Adult↗

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

Chronic hepatitis B infection in Singapore.

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)

Adolescent↗

PubMed1991

A non-fatal case report of acute fatty liver of pregnancy.

Acute fatty liver of pregnancy (AFLP) is a potentially fatal disorder that typically complicates the third trimester of pregnancy. Unrecognised, acute fatty liver of pregnancy may rapidly progress to fulminant hepatic failure, disseminated intravascular coagulation, acute renal failure and death. The outcome is highly favourable, with complete hepatic recovery, if the diagnosis is made early and pregnancy terminated promptly. The diagnostic criteria of AFLP are met if third trimester jaundice is associated with hyperuricaemia, the presence of nucleated red blood cells in the peripheral blood film and hepatic attenuation values consistent with fatty infiltration by at least one imaging technique. We report here a 38 year old Chinese woman with acute fatty liver of pregnancy, a non-fatal case complicated by extrahepatic manifestations of disseminated intravascular coagulation, haemorrhage and renal dysfunction.

Acute Disease↗

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↗