Biomedical subjects

H S Lim

Publications and source records attributed to H S Lim.

At least 37 records · Page 2Linked to original sources

PubMed2001

Cardiovascular risk factors and LDL subfraction profile in Type 2 diabetes mellitus subjects with good glycaemic control.

OBJECTIVES: To compare cardiovascular risk factors and LDL particle size in well-controlled Type 2 diabetes mellitus and normal subjects. METHODS: Ninety-three Type 2 diabetic males and 186 age-matched, male controls were studied. Glycaemic control was stable for at least 3 months prior to recruitment. None were on insulin or lipid lowering therapy. Anthropometric indices, blood pressure, lipids, glucose, insulin, apolipoprotein A1 and B, LDL subfraction by density ultracentrifugation were obtained after an overnight fast of 10 h. RESULTS: Diabetic subjects (mean HbA(1c) 6.6%+/-0.10) did not differ from controls in total cholesterol levels (5.04+/-0.08 vs. 5.16+/-0.05 mmol/l, respectively) but had lower serum HDL cholesterol (0.98+/-0.03 vs. 1.12+/-0.02 mmol/l, P<0.001), higher serum triglyceride (2.38+/-0.16 vs. 1.80+/-0.08 mmol/l, P<0.001), lower LDL(1) and LDL(2) and higher LDL(3) concentration. An LDL(3) concentration exceeding 100 mg/dl was found in 59.1% of diabetics and 39.1% of non-diabetics (P<0.001). Diabetic subjects also had higher body mass index, waist to hip ratio and insulin resistance (HOMA). Difference in LDL subfraction between groups disappeared after adjustments were made for either triglyceride or HDL cholesterol. CONCLUSION: Well controlled Type 2 diabetes mellitus subjects exhibit an increased cardiovascular burden through low HDL cholesterol and predominance of small, dense LDL particles.

Adult↗

PubMed2001

Ethnic differences and relationships in the oral pharmacokinetics of nifedipine and erythromycin.

OBJECTIVE: Our objective was to investigate ethnic differences in the oral pharmacokinetics of nifedipine and erythromycin, both typical cytochrome P4503A (CYP3A) substrates, in Koreans and Caucasians and to identify the nature of any correlations between the pharmacokinetic parameters of the two drugs. METHODS: Twenty healthy male volunteers (10 Koreans and 10 Caucasians) received single oral doses of nifedipine (10 mg) or erythromycin (500 mg) in a randomized 2-way crossover study. Pharmacokinetic evaluations were performed, and parameters were compared for the two ethnic groups. During the nifedipine study period, hemodynamic measurements were conducted to determine the pharmacodynamic relevance of the pharmacokinetic differences. RESULTS: Koreans showed area under the concentration-time curves (AUCs) for both drugs that were 1.6 to 1.7 times higher than those of Caucasians. This difference decreased to 1.3 when normalized for body weight. Significant correlation between the AUCs of the two drugs was not evident. Hemodynamic changes after nifedipine administration paralleled those of the pharmacokinetic differences, with significantly greater decreases in blood pressure and total peripheral resistance noted in Koreans. CONCLUSIONS: Koreans showed significantly lower oral clearances of nifedipine and erythromycin, probably because of genetic differences attributed to the CYP3A enzymes.

Adult↗

PubMed2001

Effects of occupation, lifestyle and genetic polymorphisms of CYP1A1, CYP2E1, GSTM1 and GSTT1 on urinary 1-hydroxypyrene and 2-naphthol concentrations.

This study was undertaken to determine the effects of occupation, lifestyle and the genetic polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1) and glutathione S-transferases micro1 (GSTM1) and 1 (GSTT1) on the concentrations of urinary 1-hydroxypyrene (1-OHP) and 2-naphthol among Korean coke oven workers and university students. The study subjects included 90 coke oven workers and 128 university students. A questionnaire was used to obtain detailed data about the work area, smoking habits and food intake of subjects. Associations between urinary polycyclic aromatic hydrocarbon (PAH) concentrations and occupation, smoking status, total airborne PAH level and genetic polymorphisms were tested. Urinary 1-OHP and 2-naphthol concentrations were higher in coke oven workers than in students and correlated significantly with work area. Urinary 2-naphthol concentrations increased with an increase in the level of cigarette smoking in students. Total airborne PAH level correlated with urinary 1-OHP concentration in coke oven workers. Urinary 1-OHP and 2-naphthol concentrations were higher in coke oven workers with the c1/c2 or c2/c2 genotype of CYP2E1 than in those with the c1/c1 genotype. Urinary 2-naphthol concentrations were higher in GSTM1-null workers than in GSTM1-positive workers. In multiple regression analysis CYP2E1 was a significant factor determining urinary 1-OHP concentrations in coke oven workers. CYP2E1 and GSTM1 were significant determinants for urinary 2-naphthol concentrations in coke oven workers and GSTM1 and smoking were prognosticators among university students. Urinary 1-OHP is a better indicator of occupational exposure to PAH in coke oven workers than 2-naphthol, whereas urinary 2-naphthol may be more sensitive for non-occupational inhalation exposure to PAH. In occupationally exposed populations CYP2E1 and GSTM1 appear to play an important role in the metabolism of pyrene and naphthalene. In individuals not occupationally exposed to PAHs GSTM1 and smoking seem to influence the urinary concentration of 2-naphthol.

Base Sequence↗

PubMed2001

Effect of inhaled budesonide on bronchial hyperresponsiveness in adolescents with clinical remission of asthma.

STUDY OBJECTIVE: Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. The regular use of inhaled corticosteroids improves BHR in patients with symptomatic asthma. The aim of this study was to determine whether BHR in adolescents with asthma remission could be reduced by prolonged treatment with inhaled corticosteroids. DESIGN: A randomized, double-blind, placebo-controlled, parallel study. PATIENTS: Thirty-seven adolescents with BHR and long-term remission of their asthma (neither symptoms nor any medication use during the previous 2 years). INTERVENTION: Subjects received inhaled budesonide (two 200-microg puffs bid; budesonide group, n = 19) or identical placebo (placebo group, n = 18) for 9 months. A separate group of patients with symptomatic asthma (symptomatic group, n = 19), using the same regimen of budesonide, was also studied. MEASUREMENTS AND RESULTS: The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) was measured before and every 3 months during treatment. There was no significant difference among the three groups for the baseline PC(20). In neither the placebo nor the budesonide group did the geometric mean of PC(20) change significantly over the 9-month period. In contrast, a significant increase in PC(20) was noted in the symptomatic group as a result of the budesonide treatment. CONCLUSION: Our data have shown that budesonide inhaled regularly for 9 months did not cause a significant improvement in the BHR of adolescents with long-term asthma remission. This suggests that the mechanism underlying BHR in this clinical setting may be different from that in symptomatic asthma.

Administration, Inhalation↗

PubMed2001

Evaluation of diagnostic methods of re-emerging malaria in Korean patients.

Malaria is one of the most important parasitic diseases especially in tropical areas. Over 300 million people are affected and the condition causes 1-3 million deaths each year. It is transmitted by the bite of infected Anopheles mosquitoes. Although Korea was declared to be free of Malaria by the WHO in 1979, malaria re-emergence has been apparent since 1993 amongst soldiers located near the De-Militarized Zone (DMZ) in the northern part of the country. Conventional microscopic examination of thin and thick blood films demonstrates the presence of the parasite and thus this method has been used to confirm the diagnosis of malaria, but it is a labor-intensive procedure and relies upon subjective interpretation. To overcome these limitations, fast and reliable methods for malaria detection have been recently introduced. In this study, we compared three kinds of antibody detection kits and one biochemical test kit that determines the presence of Plasmodium lactate dehydrogenase (pLDH) with conventional peripheral blood smears. The antibody detection methods examined were, two rapid test pack format methods and a single microplate format enzyme-linked immunosorbent assay (ELISA) kit, as manufactured by Korean companies. The sensitivities of the three commercial antibody detection kits in the early stage of malaria were 70.8%, 77.4%, and 63.6%, their corresponding specificities 90.5%, 91.8%, and 80.9%, and their accuracies 87.6%, 87.0%, and 76.7%. The sensitivity and specificity of the pLDH assay were 100% apiece and the results were in 100% concordance with the microscopy of thick blood films. Thus, the pLDH assay may be used as an alternative for conventional microscopic blood film examination, especially in emergency situations when prompt treatment is necessary.

Adult↗

PubMed2001

Development of an intelligent laboratory information system for community health promotion center.

This study aimed to develop an Intelligent Laboratory Information System (ILIS) for the community health promotion center in Kwachun city to help process an increasing number of laboratory test data in an efficient manner, and to support the clinical decision-making of public health doctors. A sample of 170 cases was used for validation of the system. Overall, the system correctly predicted 92.5% of the cases. This paper also analyzed the economic feasibility of the ILIS based on the Information Economics approach. The results showed that the ILIS not only helps screen more people by increasing the capacity of a health promotion center, but also brings in more revenue to the center.

Clinical Laboratory Information Systems↗

PubMed2001

Severe diabetes in remission: a Singapore's perspective.

INTRODUCTION: Diabetic ketoacidosis is generally thought to be the classical presentation of individuals with Type 1 diabetes. Clinicians are beginning to see individuals with atypical diabetes presenting with severe hyperglycaemia associated with or without ketosis and after the initial period of intensive insulin therapy, becoming non-insulin dependent and remaining in remission for years. So far, these patients have only been identified amongst African Americans and have only recently been reported amongst the Japanese and the Chinese in Hong Kong. We therefore set out to identify the existence of such patients in our population. MATERIALS AND METHODS: We have a database of patients admitted for diabetic ketoacidosis. From this, we recruited patients who fulfilled the criteria for atypical diabetes and proceeded to perform a retrospective analysis together with a prospective analysis of their outcome. RESULTS: We identified 10 individuals with atypical diabetes with characteristics similar to those previously described. Our data showed that these patients deferred from classical individuals with Type 1 diabetes in the following ways--older age of onset, relatively higher BMI, marked elevation in HBA1c suggesting a significant period and degree of hyperglycaemia and prolonged remission after reversal of hyperglycaemia. CONCLUSIONS: Atypical Type 2 diabetes exists in our population. Clinicians looking after individuals with diabetes should be made aware of this as there are important implications in the subsequent management of such patients.

Adult↗

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

Immunocytochemical localization of neuronal and inducible nitric oxide synthase in the retina of zebrafish, Brachydanio rerio.

Several previous studies have revealed the distribution of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) in the retina of various species. However, nothing has been reported on the nNOS and iNOS expression in zebrafish retina, even though it has been used as an effective model for developmental studies. In this study on nNOS and iNOS immunoreactivity (IR) in the zebrafish retina, iNOS-IR signals were detected in the ganglion cell layer (GC), the inner plexiform layer (IP), the outer plexiform layer (OP) and the photoreceptor layer (PR). nNOS-IR signals were also intensely detected in the GC, IP, OP and PR. These signals were very similar to the iNOS-IR signals, except for some minor differences in relative intensities. This could be explained by the speculation that the synthesis of nitric oxide by iNOS may represent a compensatory mechanism in the absence of nNOS. We described for the first time the distribution of nNOS and iNOS-IR cells in zebrafish retina. This could provide the basis for further study on the nNOS and iNOS properties of zebrafish retina.

Animals↗

PubMed2000

Activation of microglia in kainic acid induced rat retinal apoptosis.

We applied a variety of methods to follow the course of kainic acid (KA) induced retinal apoptosis, especially with regard to the spatial and temporal aspects. At 24 h after KA injection, a massive cell increase, which showed terminal transferase-mediated dUTP nick-end-labeling technique positive signals, was observed in all of the retinal layers, with the exception of the outer nuclear and photoreceptor layers. Electron microscopy further confirmed that these cells might be apoptotic body ingesting phagocytes, whose function seemed to correlate with bcl-2 mRNA up-regulation. When histochemical studies were performed to determine the cellular identity of the phagocytes, the microglia were thought to be the one and only type of phagocytes involved in the KA-induced retinal apoptosis. In conclusion, we demonstrated that after KA injection, microglia were the only phagocytes to participate in clearing apoptotic debris from the inner retinal layers, and that their function might correlate with the change in expression of the bcl-2 gene family.

Animals↗

PubMed2000

Validity and cost-effectiveness of diagnostic procedures in CS2 poisoning.

To determine relatively useful diagnostic procedures of carbon disulfide (CS2) poisoning in terms of validity and cost-effectiveness, several diagnostic tests are evaluated on 1,552 people by prevalence ratio (exposed/nonexposed), dose-response relationship, sensitivity and specificity, and the cost of the tests. Several symptoms with high kappa indices are found to be useful in various combinations, showing a consistent dose-response relationship and high exposed-nonexposed ratio. In clinicopathologic tests on functions of the kidney, liver and hematopoietic systems, eight items out of 22 have been shown to have significant dose-response relationship, mostly in liver function tests. A thorough dental examination failed to identify any useful indicator peculiar to the CS2 poisoning. Unlike Western people, the prevalence of coronary heart disease among Koreans was too low to be useful in the diagnosis of CS2 poisoning. Among four elective tests, i.e., Minnesota Multiphasic Personality Inventory (MMPI), Brain magnetic resonance imaging (MRI), nerve conduction velocity (NCV), and fluorescent angiography (FAG), the NCV appeared to be a more sensitive and specific test than the others are. Combinations of the tests improved the probability of diagnosing CS2 poisoning cases when any one test out of four was positive. Addition of other valid tests increased the probability of excluding non-cases. It was concluded that diagnosis of CS2 poisoning could be made validly and inexpensively if the diagnostic tests were carefully chosen step by step.

Adolescent↗

PubMed1999

Are substance P neurons of the paraventricular nucleus related to the osmotic regulation in the Mongolian gerbil?

In recent years, the gerbil has been used as an experimental animal for study osmotic regulation, because of its inherent high degree of water re-uptake in kidney. Many evidences to explain this characteristic accumulated on the kidney level, it do not, however, manifest what concerns on hypothalmo-hypophyseal level. In this study, we have focused on the difference between the colchicine treated gerbil and rat in distributions of substance P (SP), which is known to have antidiuretic property. Unlike rat, in which a few SP+ neuron is present, SP+ neurons were abundantly observed in the paraventricular nucleus (PVN) of the gerbil. Furthermore SP+ cells in PVN were manifested in dehydrated gerbils, in spite of non-colchicine treatment. Therefore, we suggest that the abundant SP+ neurons in PVN may be a clue to address the neuroendocrinal mechanism concerning the high degree of osmotic regulation in this animal.

Animals↗

PubMed1999

(-)-Epiafzelechin: cyclooxygenase-1 inhibitor and anti-inflammatory agent from aerial parts of Celastrus orbiculatus.

An inhibitor of cyclooxygenase (COX)-1 activity of prostaglandin H2 synthase was isolated from aerial parts of Celastrus orbiculatus Thunb. (Celastraceae), an oriental folk medicine for rheumatoid arthritis by activity-guided column chromatographic methods. The COX inhibitor was identified as (-)-epiafzelechin, a member of flavan-3-ols by the structural analysis with HR-EI-mass, 1H-NMR and 13C-NMR spectral data. The compound exhibited a dose-dependent inhibition on the COX activity with an IC50 value of 15 microM. (-)-Epiafzelechin exhibited about 3-fold weaker inhibitory potency on the enzyme activity than indomethacin as a positive control. (-)-Epiafzelechin exhibited significant anti-inflammatory activity on carrageenin-induced mouse paw edema when the compound (100 mg/kg) was orally administrated at 1 h before carrageenin treatment.

Animals↗

PubMed1999

In search of hyperglycaemia--tracing the path that leads to the new diagnostic criteria for diabetes mellitus.

The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus announced the new diagnostic criteria for diabetes mellitus on 23 July 1997. The most notable change in the new criteria is a reduction in the cut-off point for fasting plasma glucose to that of 7.0 mmol/L (126 mg/dL). The present criteria have evolved through many years of intensive research and discussions. We intend to trace the path that leads to this latest recommendation so as to understand the evolution of the present criteria and its implications.

Blood Glucose↗

PubMed1999

Increase in signal intensities on T1-weighted magnetic resonance images in asymptomatic manganese-exposed workers.

OBJECTIVES: To clarify the clinical significance of increased signal intensities on T1 weighted magnetic resonance imaging (MRI) we performed a large-scale epidemiological study on asymptomatic manganese (Mn)-exposed workers with its focus on MRI. METHODS: We randomly selected 121 male workers out of a total of 750 workers including Mn-exposed, non-exposed manual, and non-exposed clerical workers in the factories. We studied environmental and biological monitoring, neurological examination, and MRI. RESULTS: The proportion of workers with increased signal intensities among the exposed, the non-exposed manual workers, and the non-exposed clerical workers was 46.1%, 18.8%, and 0%, respectively. Especially, 73.5% of the welders showed increased signal intensities. In no subject, were clinical signs of manganism observed. The pallidal index correlated with blood Mn concentration. CONCLUSION: Increase in signal intensities on the T1-weighted image reflect recent exposure to Mn, but not necessarily manganism. At which increase of signal intensity, the progression of manganism from Mn exposure occurs, remains to be solved.

Adult↗

PubMed1998

A case report of a patient with bronchial carcinoid tumour and late presentation of Cushing's syndrome.

Bronchial carcinoid tumour with ectopic adrenocorticotrophin (ACTH) production is an uncommon cause of Cushing's syndrome. In most instances, the patient presents with clinical hyperglucocorticolism and a search for its underlying pathology leads to the discovery of an inconspicuous bronchial carcinoid tumour, if at all. Often the tumour is not immediately detectable. We report a patient who presented in the reverse order--she initially had a large asymptomatic bronchial carcinoid tumour that subsequently manifested as clinical Cushing's syndrome after remaining quiescent for four years.

Adrenocorticotropic Hormone↗

PubMed1997

Aldosterone to renin ratios in the evaluation of primary aldosteronism.

Primary aldosteronism, though an uncommon cause of hypertension, causes significant morbidity, making it important to diagnose and treat this condition. Its evaluation requires complex and time consuming investigative procedures in order to confirm the diagnosis and to differentiate between the subtypes of aldosterone producing adenoma and idiopathic hyperaldosteronism. Often, the values of renin and aldosterone are equivocal, and the diagnosis of primary aldosteronism is in doubt. In this study, we examine the use of aldosterone to renin ratios in confirming the diagnosis of primary aldosteronism when the usual criteria of suppressed renin and elevated aldosterone are not met. We have found that an aldosterone to renin ratio of 50 has a 100% specificity and 92% sensitivity for detecting primary aldosteronism. Also, an aldosterone to renin ratio of > 2000 is suggestive of an aldosterone producing adenoma.

Adrenocortical Adenoma↗