Search PubMed⌕ Search

Biomedical subjects

J S Cheah

Publications and source records attributed to J S Cheah.

At least 19 recordsLinked to original sources
PubMed1996

Case report and review of disseminated histoplasmosis in South-East Asia: clinical and epidemiological implications.

The South-East Asian region is not known to be a major endemic area for histoplasmosis. We have recently diagnosed several cases of disseminated histoplasmosis in patients from this region. We report on a well documented indigenous case of disseminated histoplasmosis in a 62-year-old poultry farmer and review the literature for other reported cases of clinical histoplasmosis in the South-East Asian region. Sporadic cases of indigenous chronic pulmonary and non-meningeal disseminated histoplasmosis in immunocompetent hosts have been reported as well as examples of disseminated histoplasmosis in immunocompromised hosts. These reports suggest that histoplasmosis is endemic to certain areas in South-East Asia and that there may be a large number of undiagnosed and subclinical cases. The recent advances in diagnostic tests for histoplasmosis are also reviewed with reference to the experience of using these tests in the reported case.

Amphotericin B↗
PubMed1996

Current management of obesity.

Obesity is common and its prevalence is rising. In Singapore, a national health survey in 1992 showed that 5% of the adult population were obese and 21% were overweight. Obesity causes much morbidity and mortality and treatment is desirable. The majority of obese patients have no known cause but it is essential to exclude any underlying cause before treatment. Antiobesity drugs should be used as an adjunct to an adequate programme of dietary restriction, exercise and behavior modification. Serotonergic drugs and adrenergic agents are available in the treatment of obesity. The short-term efficacy and safety of antiobesity drugs such as fenfluramine and d-fenfluramine are proven. The long-term use of antiobesity drugs used singly or in combination remains to be established. Many peptides (cholecystokinin, glucagon, bombesin, neurotensin, etc) with weight reduction properties are undergoing extensive studies: their clinical applications are experimental. The treatment of obesity is difficult and frustrating and antiobesity drugs have an established short-term role. In morbid obesity where the life of the patient is in danger, surgery such as gastric plication may be life-saving. The recent discovery of leptin (1994) and neuropeptide Y (1995) are important breakthrough in obesity research; hopefully further research may produce more effective treatment of obesity in man.

Adult↗
PubMed1995

Sino-atrial Wenckebach conduction in thyrotoxic periodic paralysis: a case report.

A 28-year-old male presented with thyrotoxic periodic paralysis. On admission to hospital the serum potassium level was 1.4 mmol/l. The ECG showed classical features of hypokalaemia. In addition, sino-atrial block with Wenckebach conduction was also present. With the normalization of the serum potassium, the ECG became completely normal and showed no evidence of any arrhythmia.

Adult↗
PubMed1995

Soluble T-cell markers and serum cytokines in type I (insulin-dependent) diabetes mellitus.

Markers of cell-mediated immune activation were studied in 32 Chinese patients with recent-onset insulin-dependent diabetes mellitus (IDDM) as compared with 12 patients with recent-onset non-insulin-dependent diabetes mellitus (NIDDM) and 34 normal subjects. Sera were assessed for soluble markers of T-cell activation (sCD4, sCD8, sIL-2R); the cytokines (IL-1 beta, TNF-alpha, IL-2, IL-6), and T-cell subsets were also determined. Only 1 of the 32 IDDM patients had increased sCD4 levels, 5 had increased sCD8, and 3 had increased sIL-2R. None of the sera from NIDDM patients and control subjects showed such increased levels of soluble markers. Three IDDM patients had detectable IL-1 beta and this weakly so (< 3.5 pg/ml). However, the other cytokine data and the frequency of activated T-cells, CD4+, CD8+ T-cell subsets and CD4:CD8 ratio showed no significant differences among the IDDM, NIDDM and normal subjects. Our data suggest that in addition to a low frequency of islet cell antibodies, Chinese patients with recent onset IDDM also showed a lack of serum markers of cellular activation.

Adult↗
PubMed1993

Renal cholesterol embolic disease. Case report and review of the literature.

Renal cholesterol embolization is a rare disease occurring usually in elderly men who had undergone an angiographic procedure or vascular surgery. We report a man who developed systemic cholesterol embolic disease and acute renal failure after coronary angiography. A review of the English literature for renal cholesterol embolic disease revealed a high incidence of eosinophilia (71%). Livedo reticularis and digital infarcts occurred in more than 30% of patients. Forty percent of patients required dialysis for acute renal failure of whom only one fifth recovered sufficient renal function to stop dialysis. The overall mortality was high at 64%. Skin, muscle and kidney biopsies remain the main tools for diagnosis.

Acute Kidney Injury↗
PubMed1993

Non-restricted immunoglobulin-G subclass islet cell antibodies in Chinese.

Islet cell antibodies (ICAs) in Chinese (23 IDDM, 13 NIDDM and 6 non-diabetic) were characterized for immunoglobulin isotypes and light chain specificity. All ICAs were IgG-type and none were IgM- or IgA-type (median titre: 20 JDF units; range 10-160). Light chain specificity showed that 25/36 (69.4%) of the diabetic patients had lambda and kappa chains. Half of the non-diabetic subjects had both lambda and kappa chains. The rest had only lambda chains. Isotyping for ICA-IgG subclass combination with IUIS/WHO reference monoclonal antibodies in the diabetic patients gave the following: IgG1 alone-9 (25%), IgG1+2+3-8 (22.2%), IgG1+2-11 (30.6%), IgG1+3-6 (16.7%), IgG2+3-2 (5.6%). No ICA-IgG4 was detected. The frequency of the subclasses would be: IgG1-94.4%, IgG2-58.3% and IgG3-44.4%. The distribution of ICA-IgG subclasses was not affected by diabetes type (IDDM or NIDDM) or duration of disease. Of the 6 non-diabetic subjects only one had a single ICA-IgG subclass (IgG1). Serum levels of IgG subclasses in a subgroup of the patients (n = 16) were not significantly different from normal individuals. Biochemical modification of pancreatic tissue prior to ICA testing showed that acetylneuraminic acid residues, lipid and protein components were associated with binding of ICAs. The co-existence of other autoantibodies was also tested in these 42 ICA-positive sera. Twelve individuals (1 non-diabetic) had thyroid autoantibodies. Antibodies to thyrotrophin receptor, gastric parietal cell and rheumatoid factor were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Rapid desktop method for the measurement of glycated haemoglobin HbA1c.

A new desktop monoclonal antibody-based test system (Bayer Diagnostics DCA 2000) for quantitation of glycated haemoglobin HbA1c is described and evaluated. This method involves a monoclonal antibody to HbA1c which defines its specificity. It requires 9 minutes to complete, and shows good intra- and inter-run precisions (1.3%-3.7%), at 5 HbA1c levels tested--4.1%, 5.7%, 6.1%, 9.2% and 12.4%. Results from 81 blood samples obtained from diabetic patients (3.9%-13.2% HbA1c) showed excellent correlation with a laboratory-based ion-exchange HPLC technique (y = 1.03 [Lab] + 0.103%; Pearson coefficient, r = 0.99). The test can be performed either with a capillary fingerprick or venous blood sample. Only 1 microliter of blood volume is required. Comparison of HbA1c levels of 43 paired capillary and venous samples showed excellent correlation (y = 1.00 [venous] + 0.042%; r = 0.99). The HbA1c values obtained from a cohort of 37 healthy adults, mean (+/- SD) age 33 +/- 9.01 years, gave a value of 5.5 +/- 0.42%. The calculated 95% confidence limits are 4.7%-6.3%. This quick method provides 'stat' HbA1c results, which were hitherto not possible with the laboratory-based methods.

Adult↗
PubMed1993

Occurrence of antibodies to insulin in patients with autoimmune thyroid disease.

Insulin autoantibodies (IAA) in patients with autoimmune thyroid disease (n = 97) were determined by a displacement-based ELISA technique. There were 78 patients with Graves' disease and 19 with autoimmune thyroiditis. The assay precision unit, standard deviation score, was used to assess the presence of IAA. It was determined that 7.2% were assessed to be IAA-positive. None of the patients had islet cell antibodies. Thyrotrophin receptor antibodies (TRAb) were only present in patients with Graves' disease. The mean TRAb levels in patients who relapsed (95.0 +/- 141 IU/l, n = 36) were significantly higher (p = 0.042) than those newly diagnosed for Graves' disease (38.3 +/- 36 IU/l, n = 28). Insulin autoantibody levels in these two subgroups were not different from each other. In addition, TRAb levels were not related to IAA levels. A retrospective study of 12 patients on carbimazole treatment indicated that modulation of TRAb levels had no concomitant effect on the development of IAA.

Adolescent↗
PubMed1993

Acetylcholine receptor antibody assay kit: establishment of controls in normals and non-myasthenics and evaluation of sera from patients with thyroid disease.

Immunoprecipitation assays for antibodies to the nicotinic acetylcholine receptor are a specific test for the diagnosis of myasthenia gravis. However, testing has largely been confined to reference laboratories because the preparation of the reagents is laborious, making it less accessible to practising clinicians locally. We recently acquired a test kit produced by RSR Ltd (Avenue Park, Pentwyn, Cardiff) which makes testing of serum samples practicable in smaller centres. We describe our experience in establishing normal and control values in 30 separate samples. We also assayed the sera of ten patients with thyroid disease, some of whom had ophthalmopathy and/or weakness due to periodic paralysis, and none of these tested positive. Three additional patients with thyroid disease and concurrent myasthenia gravis were also inadvertently included in the latter assay and two had high titres and one had equivocal titres. The assay is now run regularly every quarter of the year.

Adult↗
PubMed1993

Human leucocyte antigen DNA typing in Singaporean Chinese patients with Graves' disease.

Human Leucocyte Antigen (HLA) A, B, C, DR, DQ and DP locus alleles in 35 Chinese patients with Graves' disease and 80 controls were typed for using serological and DNA polymerase chain reaction/sequence specific oligonucleotide (PCR/SSO) methods. B46 was found to be strongly associated with male patients (p = 0.0002; RR = 8.2, 95% confidence interval 2.1-32.2). In HLA class 1 alleles, besides B46, the frequencies of A2 and Cw1 were increased and A24 and B63 decreased in patients compared to controls. In HLA class 2 alleles, the frequencies of DRB1*1602, *0301, *1405, DRB5*02, DQB1*0502 were increased and DRB1*1501, DQB1*0301 decreased in patients.

Adult↗
PubMed1993

Hyperthyroidism and Down syndrome.

Down syndrome has long been associated with a variety of autoimmune conditions. A significant link has also been described between Down syndrome and autoimmune thyroid disease, usually hypothyroidism. We report two cases of Down syndrome with Graves disease both with significantly elevated titres of thyrotropin receptor antibody and the presence of the HLA Bw46. We also comment on the problems in diagnosis and management of such patients.

Adolescent↗
PubMed1992

Medical treatment of Cushing's syndrome with aminoglutethimide and ketoconazole.

We report a 54-year-old Chinese man with Cushing's syndrome from bilateral adrenal adenomata in whom surgery was contraindicated because of his intercurrent medical conditions. Instead, he was successfully treated with aminoglutethimide 0.75 gm/day (which reduced his 24-hour urinary free cortisol from 628 nmol/day to 177 nmol/day in 4 weeks), followed by ketoconazole 0.6 gm/day which continued to suppress the urinary free cortisol level. We conclude that aminoglutethimide or ketoconazole offers a viable non-surgical alternative to the treatment of Cushing's syndrome.

Adenoma↗
PubMed1991

Hyperinsulinaemia in thyrotoxic hypokalaemic periodic paralysis.

To test the hypothesis that there is an abnormal serum insulin response to a carbohydrate load in thyrotoxic hypokalaemic periodic paralysis (THPP), 18 men with THPP and 15 with uncomplicated thyrotoxicosis were studied during an oral glucose tolerance test. The THPP group had significantly higher fasting insulin concentrations (27.6 [3.6] vs 13.4 [1.8] mU/l; p less than 0.005) and a higher overall insulin response to oral glucose (p less than 0.001 by ANOVA) than the thyrotoxicosis group. There were no significant differences in fasting or stimulated glucose. Hyperinsulinaemia may be an important factor in the precipitation of acute paralysis in THPP.

Acute Disease↗