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Biomedical subjects

B Y Tan

Publications and source records attributed to B Y Tan.

At least 19 recordsLinked to original sources
PubMed1999

Isolated low HDL cholesterol: an insulin-resistant state only in the presence of fasting hypertriglyceridemia.

Individuals with isolated low HDL cholesterol are at increased risk of coronary artery disease. It has been reported previously that this is an insulin-resistant state. We analyzed data from the 1992 Singapore National Health Survey with the objective of defining the clinical and metabolic parameters associated with isolated low HDL cholesterol. A total of 3,568 individuals were selected by stratified random sampling. Subjects with low HDL cholesterol (<0.9 mmol/l) and "ideal" total cholesterol (<5.2 mmol/l) were identified. Data on anthropometry, blood pressure (BP), insulin resistance, glucose tolerance, sex, smoking habit, and ethnic group were examined. We found that this group was heterogeneous. Those with fasting triglyceride (TG) >1.7 mmol/l (low HDL/high TG) displayed features of the insulin resistance syndrome characterized by obesity, higher diastolic BP, greater insulin resistance, and a greater tendency to have diabetes or impaired glucose tolerance (IGT). If fasting TG was <1.7 mmol/l (isolated low HDL cholesterol), individuals were similar to the general population in terms of insulin resistance and obesity. Both groups were more commonly men and Asian Indian. The ethnic difference in prevalence could not be explained by differences in diet, exercise, alcohol ingestion, or smoking. Our data support the view that Asian Indians are genetically predisposed to isolated low HDL cholesterol as well as the insulin resistance syndrome. The higher prevalence of isolated low HDL cholesterol, the young age at which individuals exhibit this phenotype (mean age 32.5 years), along with the greater propensity for Asian Indians to develop insulin resistance and IGT contribute to the threefold increased incidence of myocardial infarction in those <65 years of age in this ethnic group.

Adolescent↗
PubMed1999

Prevalence of diabetes and ethnic differences in cardiovascular risk factors. The 1992 Singapore National Health Survey.

OBJECTIVE: The purpose of the 1992 Singapore National Health Survey was to determine the current distribution of major noncommunicable diseases and their risk factors, including the prevalence of diabetes and dyslipidemia, in Singapore. RESEARCH DESIGN AND METHODS: A combination of disproportionate stratified sampling and systematic sampling were used to select the sample for the survey. The final number of respondents was 3,568, giving a response rate of 72.6%. All subjects fasted for 10 h and were given a 75-g glucose load, except those known to have diabetes. Blood was taken before and 2 h after the glucose load. Diagnosis of diabetes was based on 2-h glucose alone. RESULTS: The age-standardized prevalence of diabetes in Singapore residents aged 18-69 years was 8.4%, with more than half (58.5%) previously undiagnosed. Prevalence of diabetes was high across all three ethnic groups. The prevalence of impaired glucose tolerance was 16.1%, that of hypertension was 6.5%, and 19.0% were regular smokers. The total cholesterol (mean +/- SD) of nondiabetic Singaporeans was 5.18 +/- 1.02 mmol/l; 47.9% had cholesterol > 5.2 mmol/l, while 15.4% had levels > 6.3 mmol/l. Mean LDL cholesterol was 3.31 +/- 0.89 mmol/l; HDL cholesterol was 1.30 +/- 0.32 mmol/l, and triglyceride was 1.23 +/- 0.82 mmol/l. CONCLUSIONS: Prevalence of diabetes was high across all three ethnic groups. Ethnic differences in prevalence of diabetes, insulin resistance, central obesity, hypertension, smoking, and lipid profile could explain the differential coronary heart disease rates in the three major ethnic groups in Singapore.

Adolescent↗
PubMed1994

The effect of dentin bonding agents on the microleakage of porcelain veneers.

OBJECTIVES: This in vitro study was conducted to investigate the effect of dentin bonding agents on the microleakage of porcelain veneers cemented on dentin margins. METHODS: Forty human premolars were prepared on both the buccal and palatal surfaces. Each half was randomly assigned to eight groups. The veneer preparation of one group was cut entirely within enamel, to serve as controls. The remaining groups had cervical margins extending 1 mm beyond the cemento-enamel junction. Six dentin bonding agents were tested. The specimens were subjected to thermocycling and evaluated for marginal leakage using a silver nitrate stain technique. After sectioning, the extent of microleakage was measured at four interfaces: (1) incisal porcelain-composite; (2) incisal tooth-composite; (3) cervical porcelain-composite; and (4) cervical tooth-composite. RESULTS: Statistical analysis showed that the cervical tooth-composite interface had a significantly higher leakage value (p < 0.05) than the other three interfaces when the cervical margins were in dentin. SIGNIFICANCE: The dentin bonding agents tested did not significantly reduce the marginal leakage of the porcelain veneers cemented on dentin margins.

Analysis of Variance↗
PubMed1989

A profile of patients with temporomandibular disorders in Singapore--a descriptive study.

This is a descriptive study to establish the profile of 120 consecutive patients seeking relief from symptoms and dysfunction of the masticatory system at the Dental Clinic, Singapore General Hospital from February 1988-September 1988. The mean age of the patients was 29.4 years and females outnumber males by 2:1. The patients complained of TMJ clicking (66%), TMJ pain (55%), painful chewing (47%), headaches (42%), painful opening (37%), jaw locking (33%), and jaw muscle pain (23%). The possible etiological factors were recorded: macrotrauma (27%), stressful episodes (24%), unilateral mastication (53%), clenching (28%), grinding (26%) and excessive chewing habits (10%). Unilateral chewing was significantly associated with pain on opening (p less than 0.05) and joint pain (p less than 0.05). A statistical relationship was found between night grinding and laterotrusive wear of teeth (p less than 0.001). There was evidence that tension headache reported by TMD sufferers was related to temporalis muscle/tendon dysfunction (p less than 0.001).

Adolescent↗
PubMed1986

Wilson's disease revisited in the tropics.

The clinical features and investigations of 17 patients were analysed. Thirteen of them were Chinese and the rest Indians. Their ages at presentation ranged from 8 to 63 years (mean 18.35 years). Thirteen patients (76%) were symptomatic; 8 with predominantly hepatic manifestations and 5 with neurological features. Four were asymptomatic siblings. At diagnosis, however, 10(59%) had features of liver involvement singly, 3 (18%) had neurological involvement alone and 4 (27%) had mixed presentations. Family histories were available in 15 patients; 26.9% of siblings had Wilson's Disease. Serum ceruloplasmin was low in 82% of the patients. 24-hour urinary copper was measured in 16 patients and was raised in all of them. About half the patients (41%) had evidence of concomittant renal tubular dysfunction with hypouricaemia and aminoaciduria. Three patients (18%) had joint involvement at presentation. All 17 patients were treated with Penicillamine. Complications due to therapy included pemphigus in one and toxic epidermal necrolysis and later a lupus like syndrome in another. The features of clinical improvement included fading of K-F rings, improvement of neurological signs and the normalisation of serum transaminases. One patient developed primary hepatocellular carcinoma 5 years after presentation. Delay in diagnosis was encountered in half of the patients reviewed. Being a treatable condition, Wilson's Disease, although rare, should always be thought of in patients with haemolysis, liver diseases or extrapyramidal disorders.

Adolescent↗
PubMed1985

Insulin secretory capacity in Singapore diabetic subjects.

The determination of serum C-peptide has been found to be a sensitive indicator of endogenous insulin secretion, and serves to define diabetic patients who require insulin therapy i.e., insulin-dependent (Type I, IDDM) and those non-insulin dependent (Type II, NIDDM). The aim of our study is to establish the types of diabetes mellitus with C-peptide measurement in a group of diabetic subjects on different modes of therapy. Eighty-eight diabetic patients (60 males, 28 females) were studied. Thirty-four were on insulin (age 40 +/- 2 years; means +/- SEM), 35 on oral agents (54 +/- 1 years), and 19 on diet alone (46 +/- 3 years). Twenty healthy subjects (10 males, 10 females) serve as normal controls (37 +/- 3 years). Blood samples for serum C-peptide and blood glucose estimations were obtained after an overnight fast and one hour after a 75 grams oral glucose load. Fasting C-peptide levels obtained for the various groups were: 0.62 +/- 0.07 (nmol/L, means +/- SEM) (normal), 0.16 +/- 0.02 (insulin), 0.79 +/- 0.06 (oral), 2.15 +/- 0.15 (diet). The C-peptide values after oral glucose were 1.80 +/- 0.20 (normal), 0.23 +/- 0.05 (insulin), 1.72 +/- 0.02 (oral), 2.15 +/- 0.15 (diet). Both the fasting and post-glucose C-peptide concentrations were significantly lower (p less than 0.001) in the insulin group compared to the normals, whereas values for the diet and oral groups were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Epidemiology of diabetes mellitus in Singapore: comparison with other ASEAN countries.

Singapore is a tropical island city-state with a population of 2.4178 million consisting of Chinese (76.7%), Malays (14.7%), Indians (6.4%) and other races (2.2%). A diabetic survey of the adult population, aged 15 years and above, carried out in 1975, shows that the prevalence of diabetes is 1.99%; it is higher in males (2.36%) than in females (1.64%). It occurs mainly in the age group 40 years and above (5.08%) and is uncommon in the age group 15-39 years (0.40%). In males, the highest prevalence of diabetes (7.0%) is in the age group 45-49 years while in females the highest prevalence (7.2%) is in the age group 55-59 years. 43.3% of the diabetics are of normal weight while 44.3% are overweight and 12.4% are underweight. 59.6% of the diabetics are newly diagnosed while 40.4% are known diabetics; 64.3% of the newly diagnosed diabetics have no symptoms. The prevalence of diabetes among the Indians (6.07%) is significantly higher than that in Malays (2.43%) and Chinese (1.55%). Indian diabetics have a slightly higher positive family history of diabetes (12.7%) than Malays (10.9%) and Chinese (6.5%). Obesity is commoner in Malay diabetics (64.7%) than in Chinese (41.6%) and Indians (35.7%). The possible factors leading to the significantly higher prevalence of diabetes among the Indians compared to the other ethnic groups in Singapore are discussed. It is suggested that the Indian gene is susceptible to diabetes (diabetic genotype) and increased food consumption, altered lifestyle and greater obesity leads to the expression of diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Home blood glucose monitoring, glycaemic control and diabetic complications.

The aim of this study was to evaluate the effect of home blood glucose monitoring on diabetic complications and metabolic control. Forty Chinese and Indian patients participated in the Diabetic Society of Singapore National Home Blood Glucose Monitoring (HBGM) Programme. The clinical progress, the blood glucose and glycosylated haemoglobin concentrations, and the platelet aggregation of the aforementioned patients were studied over a 6-month period; the results were compared with those from a matched, albeit smaller, control group of 18 diabetic patients who were on treatment but not in the HBGM programme. At the end of the six month period, three patients in the control group showed clinical deterioration of peripheral neuropathy in contrast to one patient on HBGM. Due to the small number of patients, the difference in the findings was not statistically significant. Patients on HBGM demonstrated significant improvement in mean grouped blood glucose profile values, 135 +/- 8 to 118 +/- 5 mg/dl, p less than 0.01, and glycosylated haemoglobin levels, 10.3 +/- 0.4 to 9.3 +/- 0.3%, p less than 0.01. The platelet aggregability was unchanged. In contrast, patients in the control group developed a significant increase in platelet aggregation (30 +/- 4% to 37 +/- 5%, p less than 0.05), although the blood glucose and glycosylated haemoglobin concentrations were not significantly altered. This study demonstrated that patients on a six-month HBGM programme were able to achieve improved glycaemic control associated with a trend towards decreased deterioration of diabetic neuropathy and platelet aggregability.

Adult↗
PubMed1985

Pyogenic hepatic abscess and diabetes mellitus--a probable association.

Four patients with pyogenic hepatic abscesses are reported. There were three females and one male with an age range of 36-75 years. In all the cases, diabetes mellitus was associated. Confirmation of the abscesses was obtained by liver scanning or ultrasonography, or both. In one patient, the clinical course was complicated by sympathetic pericardial effusion with right heart failure. Two patients had percutaneous transhepatic drainage of the abscesses under fluoroscopy. All four patients eventually required laparotomy and open drainage of the abscesses. Diabetic control was achieved with insulin therapy. The common causative organism in all instances was the Klebsiella species. Three patients recovered. The remaining one developed hypotension post-operatively and died of brain-stem infarction and the hepato-renal syndrome.

Adult↗
PubMed1984

Infective endocarditis in Singapore: a six year survey.

Much has been written about the changing clinical spectrum of infective endocarditis. However our survey shows that the classical text book descriptions still hold good. The majority of our patients were young with 79% either 30 years or below. Fever was present in 93%, splenomegaly in 50% and cerebral embolism in 43% of our patients. Twelve patients had valvular heart disease and 2 patients had a ventricular septal defect. Eleven out of 14 patients had a positive blood culture. Echocardiography detected definite or probable vegetations in 66% of the examinations. Five patients responded satisfactorily to antibiotic therapy, 2 patients discharged themselves from hospital against medical advice, and 4 patients underwent successful cardiac surgery. Three patients died during medical therapy.

Adolescent↗