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Biomedical subjects

Y T Tan

Publications and source records attributed to Y T Tan.

At least 19 recordsLinked to original sources
PubMed2001

A window on the current status of diabetes mellitus in Singapore--the Diabcare-Singapore 1998 study.

The Diabcare-Singapore project was carried out in 22 clinics (general hospitals, GH and primary healthcare centres, PHC) to provide an overview of diabetes management and metabolic control status. Data from 1697 diabetic patients were collected on paper forms and analysed centrally. Type 2 diabetes mellitus patients constituted 91.4% and type I patients constituted 8.1% of population. The proportion of type I patients was greater in GH (18.1%) vs PHC (3.4%). The mean age (+/- SD) was 58.1 +/- 14.4 years and mean duration of diabetes was 10.1 +/- 7.5 years. Mean body mass index (BMI) was 25.1 +/- 4.4 kg/m2 and more than half (53%) of patients were overweight (BMI >25 kg/m2). Mean HbA1c and FBG levels were 8.0 (1.9% and 9.1 +/- 3.1 mmol/l. A total of 51% of patients had HbA1c (1% above the Upper Limits of Normal (ULN). Fasting blood glucose (FBG) was >7.8 mmol/l in 61% of patients. The majority (70%) had satisfactory levels of fasting lipids (triglycerides, total cholesterol and HDL-cholesterol). Only 19.7% practised home blood glucose self-monitoring, while 99% reported receiving some diabetes education. Sixteen percent of patients had abnormal levels of protein (>500 mg/24 h) in the urine, 3% had elevated serum creatinine levels and 36% had microalbuminuria. Retinopathy (12%), cataract (16%) and neuropathy (12%) were commonly reported diabetic complications. The data revealed suboptimal glycaemic control in about half of patients studied.

Adolescent↗
PubMed2001

The status of diabetes mellitus in primary care institution and restructured hospitals in Singapore.

The Diabcare-Asia Singapore 1998 project was carried out using data from 22 centres collected on paper forms to provide an overview of diabetes management and metabolic control status in 1697 diabetic patients from both primary health care clinic (PHC) (67%) and restructured hospital (RH) (33%) settings. PHC patients were on average older than RH patients (61.3 +/- 11.2 years vs 51.5 +/- 17.7 years), and had a shorter duration of diagnosed diabetes (9.2 +/- 6.8 years vs 12.0 +/- 8.5 years). The mean body mass index (BMI) for PHC patients was 25.5 +/- 4.4 kg/m2 vs 24.5 +/- 4.2 kg/m2 for RH patients. Proportionately more PHC than RH patients were overweight (BMI >25 kg/m2) (49% vs 42%). Patients with type I diabetes constituted 3.5% of PHC vs 18.1% of the RH cohort. HbA1c information was available for 92.5% of RH vs 69% of PHC patients. HbA1c measurements were <1% above ULN in 50% of PHC vs 37% of RH patients, while FBG was >7.8 mmol/l in >61% of all patients. Proteinuria (>500 mg/24 hrs) was reported in 13% of PHC vs 26% of RH patients tested. Microalbuminuria (20-300 mg/l) was noted in 36% of 171 RH patients tested. Oral hypoglycaemic agents were used as sole therapy in 83.5% of PHC vs 43% of RH patients. Eye, feet, renal and severe late complications were more commonly reported by RH than PHC patients. There is a variation in the patient profiles and care between PHC and RH patients.

Diabetes Complications↗
PubMed2000

Effect of Carbopol and polyvinylpyrrolidone on the mechanical, rheological, and release properties of bioadhesive polyethylene glycol gels.

This study examined the mechanical (hardness, compressibility, adhesiveness, and cohesiveness) and rheological (zero-rate viscosity and thixotropy) properties of polyethylene glycol (PEG) gels that contain different ratios of Carbopol 934P (CP) and polyvinylpyrrolidone K90 (PVP). Mechanical properties were examined using a texture analyzer (TA-XT2), and rheological properties were examined using a rheometer (Rheomat 115A). In addition, lidocaine release from gels was evaluated using a release apparatus simulating the buccal condition. The results indicated that an increase in CP concentration significantly increased gel compressibility, hardness, and adhesiveness, factors that affect ease of gel removal from container, ease of gel application onto mucosal membrane, and gel bioadhesion. However, CP concentration was negatively correlated with gel cohesiveness, a factor representing structural reformation. In contrast, PVP concentration was negatively correlated with gel hardness and compressibility, but positively correlated with gel cohesiveness. All PEG gels exhibited pseudoplastic flow with thixotropy, indicating a general loss of consistency with increased shearing stress. Drug release T50% was affected by the flow rate of the simulated saliva solution. A reduction in the flow rate caused a slower drug release and hence a higher T50% value. In addition, drug release was significantly reduced as the concentrations of CP and PVP increased because of the increase in zero-rate viscosity of the gels. Response surfaces and contour plots of the dependent variables further substantiated that various combinations of CP and PVP in the PEG gels offered a wide range of mechanical, rheological, and drug-release characteristics. A combination of CP and PVP with complementary physical properties resulted in a prolonged buccal drug delivery.

Acrylic Resins↗
PubMed2000

Molecular strategies for overcoming antibiotic resistance in bacteria.

Overuse of antibiotics in humans and livestock has led to the rapid evolution of bacteria that are resistant to multiple drugs such that even vancomycin, the drug of last resort, is no longer effective against some strains. Apart from the discovery and exploitation of the natural peptide antimicrobial agents that form part of the innate immune systems of plants and animals, there have been few new antibiotics developed in recent years. Here we review strategies designed to exploit recent advances in molecular biology, including recombinant DNA technology, molecular modelling and genomics to develop new antibacterial agents that overcome antibiotic resistance.

Animals↗
PubMed1999

Mixed polymer coating for modified release from coated spheroids.

Modified-release drug spheroids coated with an aqueous mixture of high-viscosity hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) were formulated. The preparation of core drug spheroids and the coating procedures were performed using the rotary processor and a bottom-spray fluidized bed, respectively. Dissolution studies indicated that incorporation of suitable additives, such as poly(vinylpyrrolidone) (PVP) and poly(ethylene glycol) 400 (PEG) improved the flexibility and integrity of the coat layer by retarding the drug release. An increase in coating levels applied generally retarded the release rate of the drug. However, the ratio of HPMC to NaCMC in the mixed, plasticized polymeric coat played a more dominant role in determining the dissolution T50% values. The optimal ratio of HPMC to NaCMC for prolonged drug release was found to be 3:1, whereas an increase in the amount of NaCMC in the mixed polymer coat only increased drug release. The synergistic viscosity effect of HPMC and NaCMC in retarding drug release rate was greater in distilled water than in dissolution media of pH 1 and 7.2. Cross-sectional view of the scanning electron micrograph showed that all of the coated spheroids exhibited a well-fused, continuous, and distinct layer of coating film. The drug release kinetics followed a biexponential first-order kinetic model.

Carboxymethylcellulose Sodium↗
PubMed1998

The incidence of IDDM in Singapore children.

OBJECTIVE: To determine the incidence of insulin dependent diabetes mellitus (IDDM) in children 0-12 years of age in Singapore, which has a population of 2.9 million. METHODS: The primary source was a 2-year phone and mail survey of doctors in the government and government restructured hospitals and the private sector. The secondary source was the membership records of the Diabetes Society of Singapore. RESULTS: Using the capture-recapture method, ascertainment was assessed to be 92.2% complete. The age standardised incidence rate was 2.46 per 100,000 children 0-12 years old, for the period 1992-1994 (95% confidence interval: 2.16-2.75). The data seemed to indicate a rising incidence of IDDM in this population, being 1.4/100,000 in 1992, 2.4/100,000 in 1993 and 3.8/100,000 in 1994. The male: female ratio is 1:1.85. There was seasonal variation with fewer cases from July to October and more from November to May. Five percent of patients had a first degree relative with IDDM. Malays appeared to have a lower incidence (1.23/100,000) compared to the Chinese (2.25/100,000) and the Indians (5.78/100,000). CONCLUSIONS: The incidence of IDDM in Singapore children is similar to that reported for Hong Kong and Japan, but higher than that for Shanghai. The female preponderance is similar to that seen in other Asian population. The data suggests a rising incidence of IDDM in Singapore and differences in incidence between the Malays, Chinese and Indians, but further observations are needed.

Child↗
PubMed1992

Hyperinsulinaemia in non-obese subjects with hypertriglyceridaemia: a preliminary report.

It has been known for some time that hyperinsulinaemia is associated with hypertriglyceridaemia. However, previous studies looking at the relationship between hyperinsulinaemia and hypertriglyceridaemia have included overweight subjects. The effect of obesity on the insulin status of hypertriglyceridaemic patients is uncertain. We investigated the insulin status of hypertriglyceridaemic subjects in the absence of confounding factors such as obesity, hypertension and diabetes mellitus. Our results demonstrate that basal insulin levels as well as the insulin response after an intravenous glucose challenge are higher in moderately hypertriglyceridaemic patients when compared to age and body mass index matched controls. Hyperinsulinaemia may have pathogenetic significance for hypertriglyceridaemia as well as other features of a constellation of metabolic derangements such as obesity, hypertension and glucose intolerance.

Adult↗
PubMed1992

Medical intensive care unit utilization in an acute teaching hospital.

To ascertain the profile of medical intensive care unit (MICU) utilization in the Singapore General Hospital, a prospective survey studying 162 consecutive patients admitted to MICU was conducted over a four-month-period spanning September through December 1990. While there was no racial predilection, male admissions (n = 98) outnumbered female (n = 64) by a ratio of 3:2. Male admissions averaged 56.7 +/- 1.9 years (mean +/- SEM) vs 56.4 +/- 2.69 years in female (p = 0.98). Sepsis comprised 25.3% (n = 41) of admissions during this period of which chest infection (n = 26) made up 63%. The superinfection rate was 3% comprising colonization of endotracheal and peritoneal dialysis tubes by Candida and Acinetobacter. There was a surprisingly high number of culture negative infections. These amounted to 43.9% (n = 18) out of 41 admissions for sepsis as the primary indication and 57.1% of admissions in which sepsis was an accompaniment of the main indication. The mean duration of ICU stay was 7.17 +/- 1.5 days for sepsis vs 4.7 +/- 0.5 days for admissions other than sepsis. Although this did not reach statistical significance (p = 0.79) it corroborates the prevalent impression that patients with sepsis tend to require longer intensive care. The overall mortality was 37% (n = 60). The mortality for septic patients (42.5%) is alarmingly high. This contrasts with a mortality rate of 34.7% for non-septic patients. The issue of culture negative sepsis needs to be addressed. As it stands, septic patients stay longer than non-septic ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1990

Management and outcome of gestational diabetes in Alexandra Hospital, Singapore.

We analysed 216 patients with gestational diabetes over a 3 year period. These patients were managed by a diabetic team under a standardised protocol. Forty percent of these patients required insulin therapy. The incidence of pregnancy hypertension was 14.4%, macrosomia 8.8% and major congenital malformation 3.7%. The Caesarean Section rate was 34% and the overall Perinatal Mortality Rate was 1.9%. However, neonatal morbidity rate remained high--44% of infants have had one neonatal complication and 17.6% had 2 or more complications. Pregnancy outcome was further analysed among patients with different degrees of glucose intolerance at diagnosis. We noted that both macrosomic rate, neonatal morbidity rate, as well as proportion of patients requiring insulin were higher in the group with a higher degree of glucose intolerance. There was, however, no difference in incidence of hypertension or hydramnios in the different subgroups.

Diabetes Mellitus↗
PubMed1990

The value of C-peptide level measurements in diabetes mellitus.

A prospective study of 27 patients with diabetes mellitus was done to assess their basal and glucagon stimulated C-peptide levels. Based on recommended cut off values for both basal and stimulated C-peptide levels, these patients were subsequently classified as insulin or non-insulin requiring diabetics. As in most other studies, we demonstrated a good correlation between the basal and glucagon stimulated C-peptide levels. Of the 8 patients on insulin therapy prior to this test, we found that only 2 actually required insulin i.e. had poor pancreatic reserve. Of the remaining 19 patients who were on diet and/or oral hypoglycaemic agents, we found that only one newly diagnosed diabetic had a definitive indication for insulin therapy. Among the other diabetics with poor control despite being on oral hypoglycaemic therapy, we found they had good islet cell secretory capacity for insulin.

Administration, Oral↗
PubMed1990

Diabetic retinopathy--results of a two year screening programme in two medical units in Singapore.

Three hundred patients with Diabetes Mellitus from 2 medical units in Singapore were screened for retinopathy over a 24 month period. Prevalence of retinopathy in this population was 38% with sight-threatening retinopathy in 17%. Risk factors associated with retinopathy included a longer duration of disease, the presence of hypertension, nephropathy and poor glycaemic control. Prevalence of retinopathy was higher in females. Malays and Indians had higher prevalence of retinopathy than Chinese.

Diabetic Nephropathies↗
PubMed1990

Diabetes education: the Singapore experience.

Diabetes Mellitus is one of the world's major health problems in the developed and developing countries. With increasing industrialization and urbanisation, there is an increasing frequency of diabetes in every decade.

Adolescent↗
PubMed1985

Fast fraction haemoglobin (HbA1) in the assessment of diabetes control.

The degree of control of 132 diabetic patients was assessed using historical data, urine glucose and blood glucose measurements. These were then related to HbA1, taken as the final arbiter of glycaemic control. Symptoms of hyperglycaemia and glycosuria were found to be not sensitive or specific indices of control, though symptomatic glycosuric patients tended to have higher HbA1. Fasting blood glucose correlated modestly with HbA1 (r = 0.60, p less than 0.001) but if used alone to determine degree of control, 21% and 9% of patients could be expected to be over or under assessed respectively. The assessment value of timed post-breakfast blood glucose applied only to 120 and 150 minutes post-breakfast blood glucose as they correlated well with HbA1 (r = 0.73, p less than 0.001 and r = 0.96, p less than 0.001 respectively). Clinically impression of degree of control based on a combination of historical data, urine glucose and blood glucose led to "undertreatment" in 41% and "overtreatment" in 27% of patients. The complementary value of a knowledge of HbA1 was thus highlighted.

Adolescent↗
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↗