Search PubMed⌕ Search

Biomedical subjects

W W Lee

Publications and source records attributed to W W Lee.

At least 19 recordsLinked to original sources
PubMed2001

Suboptimality in human categorization and identification.

Categorization and identification decision processes were examined and compared in 4 separate experiments. In all tasks, the critical stimulus component was a line that varied across trials in length and orientation, and the optimal decision rules were always complex piecewise quadratic functions. Evidence was found that identification is mediated by separate explicit and implicit systems. In addition, a common type of suboptimality was found in both categorization and identification. In particular, observers apparently approximated the piecewise quadratic functions of the optimal decision rules with simpler piecewise linear functions. A computational model, which was motivated by a recent neuropsychological theory of category learning, successfully accounted for this suboptimal performance in both categorization and identification. The model assigns a key role to the striatum and assumes the observed suboptimality was largely due to massive convergence of visual cortical cells onto single striatal units.

California↗
PubMed2001

Hispanic and non-Hispanic white patient pain management expectations.

This study compares emergency department (ED) pain management expectations in Hispanic versus non-Hispanic white patients with painful conditions. A prospective convenience sample of patients was enrolled at a university ED. Patient expectations of pain relief were recorded on a 100-mm visual analogue scale (VAS). Surveys from 58 Hispanics and 408 non-Hispanic whites were completed and used for data analysis. Sample size was adequate to detect a minimum difference in pain relief of 13 mm. Both groups had similar chief complaints and degree of pain at presentation. Their demographics differed in age and language spoken. Mean expectations for pain relief were not significantly different (76mm [95% confidence interval (CI) 70-82] and 72mm [95% CI 70-74]) between Hispanics and non-Hispanic whites, respectively. Mean expectations of a reasonable time to wait for pain medications were also not significantly different (31 minutes [95% CI 28-33] and 33 minutes [95% CI 26-48]) between Hispanics and non-Hispanic whites, respectively.

Adult↗
PubMed2001

Molecular analysis of CYP-21 mutations for congenital adrenal hyperplasia in Singapore.

BACKGROUND: Congenital adrenal hyperplasia arising from 21-hydroxylase deficiency is associated with mutations in the CYP21 gene on chromosome 6p. This is the first report on the mutational spectrum of the CYP21 gene in Singapore. METHODS: To catalogue the mutations, ten exons of the CYP21 gene from 28 Singaporean patients were analyzed by PCR amplification and direct sequencing. RESULTS: Common mutations in descending order were the intron 2 splice site mutation (32.7% of the alleles), the I172N mutation (23.1% of the alleles), and the R356W mutation (19.2% of the alleles). Two potentially novel mutations were discovered: (1) duplication of 111 bp from codon 21 to codon 57 (exon 1) and (2) missense mutation (L261P, exon 7). There was generally a good genotype-phenotype correlation, allowing accurate prediction of the disease severity.

Adrenal Hyperplasia, Congenital↗
PubMed2001

Epidemiologic and clinical survey of Behcet's disease in Korea: the first multicenter study.

The prevalence of Behcet's disease is the highest in the East Asian and the Mediterranean countries. Behcet's disease is also distributed in the Asian countries, but the nationwide survey has not been performed in Korea yet. The Korean Study Group for Behcet's Disease, founded in 1999, conducted a multicenter, retrospective survey on epidemiologic and clinical features of the patients with Behcet's disease from 20 hospitals around the nation from 1997 to 1999. Of 3,497 patients, 1,527 were classified into complete or incomplete type of Behcet's disease according to the revised Shimizu's classification. The sex ratio was 1:1.75 with the female predominance. Geographical distribution showed the highest frequency in Seoul (38.5%). Clinically, 98.8% had oral ulcers, 83.2% had genital ulcers, 84.3% had skin lesions and 50.9% had ocular lesions. As for the minor clinical manifestations, articular symptoms were the most frequent. The pathergy test showed positive in 15.4% of patients and revealed a higher positive rate in males (20.2%) than in females (12.7%). In conclusion, we performed the first multicenter study on Behcet's disease in Korea and revealed the female predominance, higher frequency of ocular lesions, and lower positivity of pathergy test in the patients.

Adolescent↗
PubMed2000

Modulation of collagen-induced arthritis by IL-4 and dexamethasone: the synergistic effect of IL-4 and dexamethasone on the resolution of CIA.

We investigated effects of IL-4, dexamethasone (DXM), and the combination of IL-4 and DXM, low- or high-dose, on collagen-induced arthritis (CIA) in DBA/1 mice and correlated severity of arthritis with changes in IL-10 and IFN-gamma. Compared with control mice, mice treated with IL-4 had increased IL-10 with the same degree of arthritis, whereas mice treated with high-dose DXM had decreased IL-10 and increased IFN-gamma production with less severe arthritis. Mice treated with low-dose DXM showed the absence of IL-10 and increased IFN-gamma production with a trend toward the resolution of arthritis. Mice treated with IL-4 and low-dose DXM had neither IL-10 nor IFN-gamma production but revealed less severe arthritis, compared with mice treated with low-dose DXM alone. These results suggest that the beneficial effects of high-dose DXM and the combination of IL-4 and DXM on CIA are independent of IL-10 and IFN-gamma.

Adjuvants, Immunologic↗
PubMed2000

Bilateral internal carotid artery dissection due to trivial trauma.

Internal carotid artery dissection (ICAD) is a known cause of unilateral headache and focal cerebral ischemic symptoms. Other symptoms include oculosympathetic paresis, facial pain, neck pain, subjective carotid bruits, and cranial nerve deficits. Traumatic dissection has an obvious precipitating incident preceding the neurologic or visual symptoms. An ICAD that occurs spontaneously or from trivial trauma usually lacks an obvious incident and thus requires awareness of its possibility for accurate detection and treatment. Dissections arise from a defect in the internal elastic lamina allowing penetration of blood into the arterial wall. Despite its low incidence, ICAD must be considered in young to middle-aged patients who present with headache and transient cerebral or retinal ischemic symptoms. This report describes a patient who had bilateral internal carotid artery dissections following trivial trauma. The etiologies, clinical manifestations, diagnostic modalities, treatment options, and outcomes of ICAD are discussed.

Adult↗
PubMed2000

The accuracy of pulse oximetry in the emergency department.

The objective of this retrospective study was to identify factors affecting the accuracy of pulse oximetry in the ED. Over a 3-year period, 664 consecutive emergency department (ED) patients had simultaneous arterial blood gas (ABG) and pulse oximeter readings taken. Pulse oximeter saturations (SpO2) were compared with ABG CO-oximeter saturations (SaO2) for accuracy. Multiple variables including age, sex, hemoglobin, bicarbonate, pH, and carboxyhemoglobin (COHb) were analyzed to see if they affected SpO2 accuracy. ROC curves were used to determine the best pulse oximeter threshold for detecting hypoxia. Using multivariate analysis, COHb was the only statistically significant factor affecting the accuracy of pulse oximetry. In patients with COHb <2%, SpO2 overestimated SaO2 by more than 4% in 8.4% of cases. In patients with COHb > or = 2%, SpO2 overestimated SaO2 by more than 4% in 35% of cases. The best pulse oximetry threshold for detecting hypoxia is 92%. At this threshold, if COHb is <2%, pulse oximetry has a sensitivity of 0.92 and specificity of 0.90. If COHb is > or =2%, sensitivity is 0.74 and specificity is 0.84. For patients likely to have a COHb < 2, pulse oximetry is an effective screening tool for detecting hypoxia. However, more caution must be exercised when using pulse oximetry in patients likely to have a COHb > or = 2%.

Blood Gas Analysis↗
PubMed1999

Relation of salivary cotinine to blood pressure in middle-aged cigarette smokers.

BACKGROUND: In laboratory research, nicotine administration is associated with increases in blood pressure. In epidemiologic research, however, the amount of reported cigarette smoking has no consistent relation with blood pressure. The objective of this study was to examine the relation of a nicotine metabolite (salivary cotinine) to systolic and diastolic blood pressure in current smokers being screened for entry to a clinical trial. METHODS AND RESULTS: Data were obtained from 5164 middle-aged cigarette smokers during screening for the Lung Health Study. Multiple linear regression was used to examine the association of salivary cotinine and number of cigarettes smoked per day to systolic and diastolic blood pressure with age, body mass, years of education, alcohol intake, and recent caffeinated beverage use controlled in all analyses. Although smoking frequency was unrelated to blood pressure, salivary cotinine was related to greater systolic blood pressure in both men and women and greater diastolic blood pressure in men. CONCLUSIONS: The association between salivary cotinine and blood pressure in these analyses suggests that long-term nicotine exposure may be related to modest elevations in blood pressure in cigarette smokers.

Biomarkers↗
PubMed1999

Epstein-Barr virus-associated lymphoproliferative skin lesion with recurrent necrotic papulovesicles of the face.

A 24-year-old man showed recurrent necrotic papulovesicles of the face. The cutaneous lesions started with erythema, followed by vesicles, necrosis, and crusting, and leaving depressed scars. Light avoidance did not prevent the development of the lesions. Histologic examination revealed lymphoproliferative lesions confined to the skin. Latent Epstein-Barr virus (EBV) infection was detected in the lymphoid cells from the skin lesions by in situ hybridization. A moderate to high dosage of corticosteroids suppressed the development of new skin lesions, but relapses occurred when these systemic corticosteroids were tapered.

Adult↗
PubMed1998

Early and late weight gain following smoking cessation in the Lung Health Study.

The authors examine weight gains associated with smoking cessation in the Lung Health Study (1986-1994) over a 5-year follow-up period. A cohort of 5,887 male and female smokers in the United States and Canada, aged 35-60 years, were randomized to either smoking intervention or usual care. Among participants who achieved sustained quitting for 5 years, women gained a mean of 5.2 (standard error, 5.0) kg in year 1 and a mean of 3.4 (standard error, 5.5) kg in years 1-5. Men gained a mean of 4.9 (standard error, 4.9) kg in year 1 and a mean of 2.6 (standard error, 5.8) kg in years 1-5. In regression analyses, smoking-change variables were the most potent predictors of weight change. Participants going from smoking to quit-smoking in a given year had mean weight gains of 2.95 kg/year (3.61%) in men and 3.09 kg/year (4.69%) in women. Over 5 years, 33% of sustained quitters gained > or = 10 kg compared with 6% of continuing smokers. Also among sustained quitters, 7.6% of men and 19.1% of women gained > or = 20% of baseline weight; 60% of the gain occurred in year 1, although significant weight gains continued through year 5. The average gains and the high proportions of sustained and intermittent quitters who gained excessive weight suggest the need for more effective early interventions that address both smoking cessation and weight control.

Adult↗
PubMed1998

Neuroanatomical correlates to central deafness.

Our research experience with five centrally deaf patients showed that damage to various anatomical sites could result in central deafness. This finding was contrary to the commonly held notion that both Heschl's gyri must be severely damaged to yield central deafness. To discover whether lesions in various brain areas could cause central deafness, we reviewed 33 cases of central deafness reported in the literature which had sufficient radiological data to determine the anatomical regions involved. Both Heschl's gyri were involved in the majority of these cases, but there were definite exceptions. In these exceptional cases of central deafness, subcortical areas were involved (usually the internal capsule), as was the insula. Overall findings are discussed and recommendations are offered for the future study of centrally deaf patients.

Adult↗
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↗
PubMed1997

Olfactory dysfunction in patients with head trauma.

BACKGROUND: The ability to smell is commonly altered by head trauma (HT). However, the nature, prevalence, prognosis, and etiology of such alterations are poorly understood. OBJECTIVES: To quantitatively determine the degree of olfactory function in patients with HT-related chemosensory complaints and to examine the influences of age, sex, HT severity, time since HT, and other variables on such function. Also, to use quantitative magnetic resonance imaging (MRI) to establish whether and to what degree damage to the olfactory bulbs and tracts, frontal lobes, and temporal lobes occurs. PATIENTS AND METHODS: Two hundred sixty-eight patients with HT from the University of Pennsylvania Smell and Taste Center, Philadelphia, were administered a quantitative odor identification test, a depression inventory, and a medical history questionnaire; 66 were retested after individual test-retest periods ranging from 1 month to 13 years. The volume of olfactory-related brain structures was determined in 15 patients and 15 controls using MRI. RESULTS: One hundred seventy-nine patients (66.8%) had anosmia, 55 (20.5%) had microsmia, and 34 (12.7%) had normosmia. Frontal impacts produced less dysfunction than back or side impacts. Of the 66 retested patients, 24 (36%) improved slightly, 30 (45%) had no change, and 12 (18%) worsened; only 3 patients, none of whom initially had anosmia, regained normal olfactory function. Trauma severity was related to olfactory test scores in patients with microsmia. Parosmia prevalence decreased from 41.1% to 15.4% over an 8-year posttrauma period. Olfactory bulb and tract volumes of male, but not female, patients with HT were greatly reduced relative to volumes of controls. CONCLUSIONS: Patients complaining of HT-related olfactory dysfunction typically have anosmia and rarely regain normal olfactory ability, parosmia prevalence decreases over time in such patients, and damage to olfaction-related brain structures can be observed in most such patients using an appropriate MRI protocol.

Adult↗
PubMed1997

Conventional and maximum length sequences middle latency response in patients with central nervous system lesions.

Conventional and maximum length sequence (MLS) middle latency response (MLR) procedures were compared across several parameters for control patients and patients with central nervous system lesions. There were similar findings for both populations and both types of MLR for the absolute latencies of Na and Pa waves. Middle latency waves were absent more often in the neurologic than control subjects for both the conventional and MLS-MLR procedures. Overall, more MLR waves were present for the MLS technique than for the conventional MLR technique. Differences in wave amplitude were significant for several recording sites when comparing neurologic with control groups, but findings were similar for wave amplitude when comparing the two types of MLR procedures for the neurologic population. Based on these findings, no clear diagnostic advantage was shown for using the MLS-MLR technique. These findings are further discussed.

Adolescent↗
PubMed1996

Development of the 12-item Cross-Cultural Smell Identification Test (CC-SIT).

The development of the 12-item Cross-Cultural Smell Identification Test (CC-SIT), based upon items from the University of Pennsylvania Smell Identification Test (UPSIT), is described. In developing this test, the authors initially selected UPSIT items that are familiar to most persons from North American, European, South American, and Asian cultures. The CC-SIT was then administered to 198 people ranging in age from 5 to 96 years, and the the test scores were compared to analogous items from UPSITs administered to 198 age-, sex-, race-, and smoking-habit-matched control subjects. Since the pattern of test scores did not differ for the two groups, the authors developed normative data for the 12-item test using equivalent UPSIT items sampled from a database containing UPSIT scores for 3760 subjects. Norms are provided for determining the percentile ranks of a given patient's score as a function of age and gender. The CC-SIT provides, for the first time, a self-administered means for reliably assessing olfactory function in less than 5 minutes.

Adolescent↗
PubMed1996

Methacholine reactivity predicts changes in lung function over time in smokers with early chronic obstructive pulmonary disease. The Lung Health Study Research Group.

As part of a clinical trial of early intervention in chronic obstructive pulmonary disease (COPD) (the Lung Health Study), 5,733 smokers with mild to moderate airflow obstruction underwent methacholine challenge tests at baseline. All participants were randomized to receive either usual care (no intervention) or special intervention, consisting of intensive smoking cessation counseling and the prescription of a metered-dose inhaler containing either ipratropium bromide or placebo (two inhalations three times daily). For this report, we analyzed the relationship between baseline methacholine reactivity and subsequent change in lung function. Methacholine reactivity was expressed as a logarithmic function of the two-point slope of percent decline in FEV1 over the concentration of methacholine (LMCR). Using a random effects linear model, LMCR was found to be a strong predictor of change in FEV1% predicted, after controlling for baseline lung function, age, sex, baseline smoking history, and changes in smoking status. Significant interactions were found between reactivity and smoking behavior. In the first year, participants who quit smoking showed improvement in FEV1, whereas continuing smokers showed worsening, and between Years 1 and 5, lung function declined to a greater extent in continuing smokers than in sustained quitters. For both time periods, these quitter/smoker differences increased as a function of airway reactivity. These findings indicate that methacholine reactivity is an important predictor of progression of airway obstruction in continuing smokers with early COPD, independent of the baseline level of obstruct.

Bronchoconstrictor Agents↗
PubMed1996

A recent case of congenital malaria in Singapore.

We report a case of congenital malaria in a 2-month-old baby girl, born in Singapore of a Singaporean mother, who presented with fever for one week, gross hepatosplenomegaly and anaemia (haemoglobin 5.6 g/dL) and thrombocytopenia. Peripheral blood films showed Plasmodium vivax. There was no local transmission at that time, but the mother had spent the first 6 months of her pregnancy in Pakistan, where she had been treated for prolonged fever at 4 months amenorrhoea with ibuprofen alone. The mother and 2 siblings were asymptomatic and repeatedly tested negative on blood films for malaria parasites, but the mother tested positive for antibodies to Plasmodium on the Fluorescent Antibody Test. The child was treated with oral chloroquine and made an uneventful recovery. We postulate that this is believed to be the first recent case of congenital malaria in Singapore since it was declared malaria free in 1982. The diagnosis should be considered in babies of mothers who have travelled to places where malaria is endemic, as maternal infection may be unrecognised, and the child may be asymptomatic at birth.

Antimalarials↗