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Biomedical subjects

W R Lee

Publications and source records attributed to W R Lee.

At least 37 records · Page 2Linked to original sources
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

Oncogenic base substitution mutations in circulating leukocytes of normal individuals.

The background frequency of mutations in human tissues is an important issue in cancer susceptibility and genotoxic exposure determinations. Here we report the detection of rare mutant leukocytes containing oncogenic base substitutions of the Harvey-ras, N-ras, and p53 genes by the Needle-in-a-Haystack mutation assay with a sensitivity of one cell in a million. Altogether, we detected and identified 17 independent mutations of 66 separate base site analyses of peripheral blood specimens obtained from 19 apparently normal individuals. Two individuals harbored a substantially increased frequency of mutant cells, representing 9 of the 17 independent mutations found. These results suggest that up to 1 in 10 normal individuals may harbor a significant frequency of oncogenic mutations in circulating leukocytes.

Base Sequence↗
PubMed2000

A preliminary analysis of health-related quality of life in the first year after permanent source interstitial brachytherapy (PIB) for clinically localized prostate cancer.

PURPOSE: To prospectively assess the health-related quality of life (HRQOL) and changes in HRQOL during the first year after permanent source interstitial brachytherapy (PIB). METHODS AND MATERIALS: Thirty-one men treated with PIB between September 1997 and March 1998 completed a quality of life (functional assessment of cancer therapy-prostate: FACT-P) and a urinary symptom questionnaire (international prostate symptom score: IPSS) prior to treatment (T0), 1 month (T1), 3 months (T3), 6 months (T6), and 12 months (T12) following PIB. All participants were treated with 125I alone. Repeated measures analyses of variance (ANOVA) were conducted on all quality of life and urinary outcome measures for all 31 patients at all time points. RESULTS: The median age of the study population was 66 (range 51-80). All men had clinical T1c-T2b prostate cancer. The Gleason score was < or =6 in 27/31 (87%). Median pretreatment PSA was 7.8 ng/ml (range 1.1-20.6). The mean score (and standard deviation) at T0, T1, T3, T6, and T12 for the FACT-P questionnaire are as follows: 140.5 (13.5), 132.7 (15.3), 137.2 (17.4), 140.1 (16.0), and 142.4 (15.3). For the global test across time, statistically significant differences were observed for the cumulative scores of FACT-P (p<0.0012). The decrease in HRQOL was most marked 1 month following PIB. Examination of the subscales within the FACT-P instrument demonstrated statistically significant changes over time for the following: physical well-being (PWB), functional well-being (FWB), and prostate cancer (PCS). By 3 months, all HRQOL measures had returned to near baseline. The mean score (and standard deviation) at T0, T1, T3, T6, and T12 for the IPSS questionnaire are as follows: 8.3 (5.5), 18.4 (8.0), 15.7 (7.4), 13.7 (7.4), and 10.2 (5.7). For the global test across time, statistically significant differences were observed for the IPSS scores (p<0.0001). The maximum increase in IPSS occurred 1 month following PIB. CONCLUSION: The results of this preliminary analysis suggest that clinically meaningful decreases in HRQOL, as measured by the FACT-P instrument, are evident within weeks after PIB. By 3 months, however, FACT-P scores return to near baseline levels. A validated instrument designed to measure urinary symptoms (IPSS) demonstrates that moderate to severe urinary symptoms persist for at least 3-6 months following PIB. One year following PIB, the scores on the FACT-P and IPSS questionnaires had returned to baseline.

Aged↗
PubMed2000

Postimplant analysis of transperineal interstitial permanent prostate brachytherapy: evidence for a learning curve in the first year at a single institution.

PURPOSE: The utilization of transperineal interstitial permanent prostate brachytherapy (TIPPB) is increasing in the United States. Quality assessment of TIPPB is in its infancy, and to date, dosimetric analyses have only been reported from centers with a large experience in prostate brachytherapy. The purpose of this report is to critically analyze the dosimetric coverage achieved following TIPPB in the first 63 cases performed by a multidisciplinary group of investigators with no prior experience with TIPPB. METHODS AND MATERIALS: The information in this report concerns the first 63 men treated with TIPPB alone at our institution between September 1997 and September 1998. All men were treated similarly, adapting the methods described by Blasko and Grimm. All men were treated with 125I. The prescription dose was 144 Gy according to the TG43 formalism. TIPPB was performed jointly by a radiation oncologist and a urologist. One month following TIPPB, all men underwent a computed tomography (CT) scan of the pelvis according to a protocol using 3-mm abutting slices. CT images were transferred by a local area network to a commercially available treatment planning system and dose-volume histograms were calculated with 0.5-mm pixel spacing. A variety of dosimetric endpoints were examined. A single measure of dose homogeneity, the dose-homogeneity index (DHI), is defined as the volume within the prostate that receives 100-150% of the prescription dose (144-216 Gy) divided by the volume within the prostate that receives 100% of the prescription dose (144 Gy). Three measures of target (prostate) dosimetric coverage are provided. C100 is defined as the percentage of the prostate volume defined on postimplant CT that receives at least 100% of the prescription dose. C90 and C80 are similar but represent the percentage of the prostate volume that receive 90% and 80% of the prescription dose, respectively. Statistical analyses were performed using commercially available computer software. To investigate any changes with time the first 30 cases (group 1) are compared to cases 31-63 (group 2). All p-values are two-sided. RESULTS: The mean C100, C90, and C80 for all 63 patients were 80.7% (SD 10.1), 85.1% (SD 10.2), and 89.3% (SD 9.5). The quantifiers of implant adequacy were all improved in the most recent 33 patients compared to the first 30 patients, (group 1: C100, 75.8% [SD 12.2], C90 79.9% [SD 11.4], C80 84.3% [SD 11.1]; group 2: C100, 85.2 [SD 7.0], C90 89.9% [SD 5.8], C80 93.8% [SD 4.2]; p<0.001). The mean DHI was 0.538 SD (0.124). A multivariate model incorporating a number of variables (ultrasound volume, CT volume, total activity, activity/ seed, implant number) with C100 as the dependent variable found that the implant number was the only statistically significant predictor of C100 (p = 0.0001). Using C90 and C80 as the dependent variable produced similar results (C90, p = 0.0001; C80, p = 0.0001). CONCLUSION: In this single institution experience with the first 63 men receiving TIPPB by a multidisciplinary group of investigators, there is evidence for a learning curve. All quantifiers of implant adequacy improved as clinicians gained experience. In the most recent group of patients, quantifiers of implant adequacy are similar to those reported from other groups with significantly more experience with TIPPB.

Aged↗
PubMed2000

Transformation of cell type in uveal melanomas: a quantitative histologic analysis.

OBJECTIVE: To describe the cytologic transformation and tumor progression in a series of uveal melanomas. METHODS: Fifteen cases of uveal melanoma, treated by primary transscleral local resection without primary adjuvant treatment, needed enucleation because of local tumor recurrence. Cytologic and cell morphometric features of the primary tumor and the intraocular recurrence were compared, with evaluation of the amounts of intermediate cells, epithelioid cells, mitotic figures, and nucleolar area. RESULTS: The cases were categorized into 2 groups, according to their cytologic characteristics. In the first group (5 cases), there was no cytopathological transformation in the recurrent tumor. The nucleolar area was increased in only 1 case. In the second group (10 cases), the recurrent tumors showed transformation into a more epithelioid cell type. In all but 1 case there was an increase in epithelioid cells in the tumor recurrence. The nucleolar area was increased significantly in all cases. The mean local recurrence interval in all cases was 15.3 months, with no difference between the groups. Death from metastases occurred in 7 cases in which the nucleolar area was 4.2 microm(2) in the primary tumor. CONCLUSIONS: These findings demonstrate that, in an individual tumor, the cytologic phenotype can change considerably even after a relatively short time, resulting in an increase in tumor-related mortality. CLINICAL RELEVANCE: Studies on the natural course of uveal melanoma have been very limited and based purely on observations on the progression of melanomas in terms of size and alteration of various clinical characteristics.

Adult↗
PubMed2000

Retinal vasoproliferative tumors: surgical management and histological findings.

Vascular masses occurring in the peripheral retina have been described extensively in the literature. Many terms, including "presumed acquired hemangiomas," "hemangioma-like," "angiomatous masses," "angioma-like," "peripheral retinal telangiectasis," and "vasoproliferative tumors," have been suggested that reflect the lack of the known histological features and the potentially variable causes. We describe the histological features of 2 patients who underwent transcleral local resection as management for suspected choroidal melanoma. Pathological examination of these tumors reveals the constituents to be primarily benign glial cell proliferation with secondary vasoproliferation. The weight of the literature agrees with a reactionary process. We therefore suggest the term "reactionary retinal glioangiosis." Transcleral resection has a place where diagnosis is difficult. It prevents an unnecessary enucleation and allows accurate tissue diagnosis.

Cell Division↗
PubMed2000

The changing demography of diabetes mellitus in Singapore.

Diabetes mellitus has been on the rise in Singapore, while Singaporeans are becoming more affluent, our lifestyles are more sedentary and our population is ageing rapidly. The prevalence of diabetes mellitus rose from 2% in 1975 to 4.7% in 1984, 8.6% in 1992 and 9.0% of adults 18-69 years old in 1998. Malay and Indian women and Indian men were at higher risk, with 14.3, 14.9 and 16.7% prevalence rates, respectively. A further 15% of the adult population have impaired glucose tolerance (IGT). Diabetes was a factor in 39.7% of strokes and in 9.3% of all deaths in Singapore, and is the sixth most common cause of death. In the Diabcare Singapore 1998 Study, 91% of participants were diagnosed with Type 2 diabetes, with mean BMI of 25.1+/-4.4 kg/m(2). The incidence of Type 1 diabetes in childhood is 2.46 per 100000 children 0-12 years of age, while Type 2 diabetes in childhood is an emerging problem. The prevalence of obesity (BMI >30 kg/m(2)) among persons aged 18-69 years rose to 6% in 1998, up from 5.1% in 1992. The prevalence of obesity was highest among the Malays (16.2%) followed by the Indians (12.2%) and the Chinese (3.8%). About 12% of schoolchildren are obese. Increased efforts must be made to change lifestyle and eating patterns in our society, reduce childhood obesity and encourage adults to make lifelong sports and exercise part of the Singaporean way of life. Singapore has one of the world's fastest ageing populations, and even now, 32.4% of Singaporeans 60-69 years of age have diabetes. We should consider screening for diabetes in obese schoolchildren and seek to improve quality of care for people with diabetes, including enlisting the aid of community organisations to improve access to diabetes education, monitoring, support and complications screening services.

Adolescent↗
PubMed2000

Decreased entropy of symbolic heart rate dynamics during daily activity as a predictor of positive head-up tilt test in patients with alleged neurocardiogenic syncope.

Entropy measures of RR interval variability during daily activity over a 24h period were compared in 30 patients with a positive head-up tilt (HUT) test and 30 patients with a negative HUT test who had a history of alleged neurocardiogenic syncope. Two different entropies, approximate entropy (ApEn) and entropy of symbolic dynamics (SymEn), were employed. In patients showing a positive HUT test, the entropies were significantly decreased when compared with the patients with a negative HUT test. In addition, SymEn in the patients with a negative HUT test was significantly lower than in the normal controls. Discriminant analysis using SymEn could correctly identify 89.3% (520/582) of the 1 h RR interval data of the patients with a positive HUT test regardless of the time of day. Baseline entropies of heart rate dynamics during daily activity were found to be significantly lower in patients with alleged neurocardiogenic syncope and a positive HUT test than in those with the same history but with a negative HUT test. The decreased entropy of symbolic heart rate dynamics may be of predictive value of a positive HUT test in patients with alleged neurocardiogenic syncope.

Adult↗
PubMed2000

Prevalence and risk factors of silent cerebral infarction in apparently normal adults.

Cerebrovascular disease is a major cause of death and disability in adults. Silent cerebral infarction (SCI) portends more severe cerebral infarctions or may lead to insidious progressive brain damage resulting in vascular dementia. This study was designed to evaluate the prevalence and risk factors of SCI in an apparently normal adult population. Nine hundred ninety-four consecutive symptom-free adults (mean age 49.0+/-7.7; men:women 830:164) who underwent brain magnetic resonance imaging at the Center for Health Promotion at Samsung Medical Center were assessed. All were neurologically normal in history and physical examination. A total of 121 SCI lesions was observed in 58 subjects. The lesion prevalence adjusted for patient age was 5.1%. There was no gender difference in prevalence. Ninety-nine lesions were <1 cm in diameter, 15 were between 1 and 2 cm, 3 were between 2 and 3 cm, and 4 were >3 cm in diameter. The most frequent site of the SCI lesion was basal ganglia, after which the periventricular white matter, cerebral cortex, and thalamus were the most frequent sites. Old age, hypertension, a history of coronary artery disease, evidence of cardiomegaly in chest radiographs, and high fasting glucose/hemoglobin A1c levels were associated with SCI on univariate analysis. Multivariate analysis demonstrated old age and hypertension to be independent risk factors for SCI, and mild alcohol consumption was revealed as an independent protective factor against SCI.

Adult↗
PubMed2000

Penile length of newborns in Singapore.

Micropenis is an important sign in congenital hypopituitarism and various disorders. Documented norms for penile length exist only for babies of Caucasian and Middle-Eastern origin. This study was carried out to establish such norms for Asian newborns. We studied 228 male live births within their first three days of life. Stretched penile lengths were marked off on unmarked wooden spatulas, which were placed vertically along the dorsal aspect of the penis, with one rounded end on the pubic bone. The mean penile length +/- S.D. for the full-term Asian baby was 3.6 +/- 0.4 cm. Race had a significant effect: Chinese 3.5 cm, Malay 3.6 cm and Indian 3.8 cm. Penile length correlated with birth weight and gestational age. Asian babies thus have similar norms to Caucasian babies. An Asian newborn whose penis measures less than 2.6 cm has micropenis and may need prompt investigation for underlying endocrine disorders.

Birth Weight↗
PubMed2000

Takayasu's arteritis: assessment of disease activity with contrast-enhanced MR imaging.

OBJECTIVE: The purpose of this study was to evaluate the role of contrast-enhanced MR imaging in the determination of disease activity in patients with Takayasu's arteritis. SUBJECTS AND METHODS: High-resolution contrast-enhanced T1-weighted spinecho MR imaging using small fields of view (14-20 cm) and thin slices (4-5 mm) was performed in 26 patients with Takayasu's arteritis and 16 healthy subjects. The degree of aortic mural enhancement was assessed by measuring signal intensity and by visually estimating it in comparison with that of the myocardium. RESULTS: Contrast-enhanced MR imaging showed more enhancement of thickened aortic wall compared with myocardium, thus suggesting active Takayasu's arteritis on MR imaging in 16 patients. Determination of disease activity using contrast-enhanced MR imaging was concordant with clinical findings in 23 patients (88.5%). Contrast-enhanced MR findings were concordant with laboratory findings in most patients (erythrocyte sedimentation rate in 92.3% [24/26] and C-reactive protein in 84.6% [22/26]). The measured signal intensity of the aortic wall relative to that of myocardium during the early phase of contrast-enhanced MR imaging correlated well with the erythrocyte sedimentation rate (r = 0.78, p < 0.005) and with the C-reactive protein level (r = 0.63, p < 0.005). CONCLUSION: Contrast-enhanced MR imaging provides information about disease activity of Takayasu's arteritis, which may be useful in the diagnosis and treatment of Takayasu's arteritis.

Adolescent↗
PubMed2000

Aging affects the association between endothelial nitric oxide synthase gene polymorphism and acute myocardial infarction in the Korean male population.

OBJECTIVES: The aging process affects responsiveness and other functions of endothelium and vascular smooth muscle cells, predisposing the old vessels to the development of atherosclerotic lesions. Endothelial nitric oxide synthase (ecNOS) gene polymorphisms were shown to affect the occurrence of acute myocardial infarction (AMI). We hypothesized that aging may affect the association between the ecNOS gene polymorphism and AMI. METHODS: We investigated the age-related distribution of the ecNOS gene a/b polymorphism in 121 male AMI patients and 206 age-matched healthy male controls. RESULTS: The aa, ab and bb genotypes were found in 1, 49 and 156 cases among the control subjects and 5, 23 and 93 cases among the AMI patients, respectively. There was a significant correlation between the ecNOS polymorphism and AMI (p = 0.045). When the correlation was analyzed by age, the significance remained only in the group below the age of 51 (p = 0.009). The proportion of smokers was increased in the young patients when compared to the old patients (p = 0.033), indicating that smoking also has greater effect on the younger population. The incidences of hypertension and diabetes mellitus, however, were similar in both populations. CONCLUSION: Our work provides the first evidence that links ecNOS polymorphism to the risk of AMI in relation to age. Young persons who smoke or have ecNOSaa genotype may have an increased risk of developing AMI. The functional as well as structural changes associated with aging in the vascular endothelium may mask the effect of the ecNOS polymorphism in the development of AMI in old persons.

Adult↗
PubMed2000

A prospective analysis of patient-reported quality of life after prostate brachytherapy.

The purpose of this study was to prospectively assess the patient-reported quality of life (QOL) and changes in QOL during the first 3 months after prostate brachytherapy (PB). Seventy-four men treated with PB between September 1997 and December 1998 completed a QOL questionnaire (Functional Assessment of Cancer Therapy-Prostate [FACT-P]) and a measurement of urinary symptoms (International Prostate Symptom Score [IPSS]) before treatment (T0), 1 month (T1), and 3 months (T3) following PB. All participants were treated with (125)I alone. The mean score (and standard deviation) at T0, T1, and T3 FACT-P questionnaire are as follows: 139.2 (15.7), 125.4 (20.2), and 133.0 (18.2). For the global test across time, statistically significant differences were observed for the cumulative scores of FACT-P (P < .0001). Examination of the subscales within the FACT-P instrument demonstrated statistically significant changes over time for the following: physical well-being, functional well-being and the prostate cancer subscale. The mean score (and standard deviation) at T0, T1, and T3 for the IPSS questionnaire are as follows: 9.1 (5.9), 20.0 (7.8), and 16.6 (7.2). For the global test across time, statistically significant differences were observed for the IPSS scores (P < .0001). Clinically meaningful decreases in QOL are evident within weeks after PB. Moderate to severe urinary symptoms persist for at least 3 months following PB.

Aged↗