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Biomedical subjects

D W Chan

Publications and source records attributed to D W Chan.

At least 109 records · Page 6Linked to original sources
PubMed1995

Laboratory and bedside evaluation of portable glucose meters.

A two-phase, laboratory and bedside, evaluation of blood glucose meters was conducted in this study. Four meters, the AccuData Easy (Boehringer-Mannheim, Indianapolis, IN), HemoCue Glucose (HemoCue, Mission Viejo, CA), LifeScan One Touch II (LifeScan, Milpitas, CA), and Miles Encore QA (Miles, Elkhart, IN) systems, were compared to the Nova Stat Profile 5 (Nova, Waltham, MA) as the laboratory reference. Precision, linearity, correlation to the laboratory method, interference from hematocrit, data management, and operator preference were examined. None of the meters were found to satisfy all of the study's evaluation criteria. Therefore, institutions must weigh which criteria are most important to their individual settings. Although the HemoCue Glucose was found to be technically superior, this meter had no data management capabilities. The Encore QA had greater variance and low bias, whereas the AccuData Easy had bias affected by hematocrit and glucose concentration, and the One Touch II had a negative hematocrit bias and limited linear range when compared to the Nova. Only meters meeting both minimal analytical performance and computerization requirements, the One Touch II and AccuData Easy, were selected for further evaluation. At the bedside, the One Touch II demonstrated performance consistent with the lab evaluation, whereas the AccuData Easy showed greater imprecision in the low glucose range and a correlation that varied with sample type: capillary, venous, or arterial blood. This evaluation indicates that the clinician must interpret near-patient glucose results with respect to meter limitations. FDA approval and marketing statistics, alone, are insufficient to judge the performance of the meters in routine institutional use. Independent method validation, under actual operating conditions, is a better means of predicting future performance of the meters.

Blood Glucose↗
PubMed1995

Burnout and coping among Chinese secondary school teachers in Hong Kong.

The tripartite components of burnout and eight coping strategies were assessed in a sample of 415 Chinese secondary school teachers in Hong Kong. While emotional exhaustion and depersonalisation were relatively undifferentiated among these teachers, a reduced sense of accomplishment as a distinct component of burnout was generally reported. The findings that avoidant coping strategies were consistently related to all three aspects of burnout suggested that teachers employing escape-avoidance to cope with stressors might be more prone to burnout. Implications for promoting certain patterns of coping to combat burnout were discussed.

Adaptation, Psychological↗
PubMed1995

Reasons for living among Chinese adolescents in Hong Kong.

Two hundred and seventy-nine secondary school students in Hong Kong responded to the Chinese version of the Reasons for Living Inventory. The importance of these reasons could be adequately described by five dimensions interpreted as Positive Values and Self-Efficacy, Optimism, Family Concerns, Concerns for Social Disapproval, and Suicidal Fears. These dimensions corresponded closely to the original subscales of the inventory. Implications of the importance of gender and age group differences in endorsing coping beliefs, rather than fears, in time of crisis are discussed.

Adaptation, Psychological↗
PubMed1994

Elevated urine thrombomodulin/creatinine ratio in severely preeclamptic pregnancies.

A relationship between the urine thrombomodulin/creatinine ratio and preeclampsia was investigated. Preeclamptic women had a higher urine thrombomodulin/creatinine ratio than did matched controls. However, significantly elevated urine thrombomodulin/creatinine ratios were found in severely, but not mildly, preeclamptic pregnancies.

Adult↗
PubMed1994

Elevated serum human chorionic gonadotropin as evidence of secretory response in severe preeclampsia.

OBJECTIVE: Because preeclampsia is a trophoblastic disorder and human chorionic gonadotropin is secreted from trophoblast, we sought to determine whether measurement of serum human chorionic gonadotropin might reflect a different trophoblastic secretory response of preeclampsia. STUDY DESIGN: Twenty patients with mild preeclampsia and 12 with severe preeclampsia were matched with 32 healthy, normotensive women in the third trimester with singleton pregnancies. Serum total human chorionic gonadotropin and total human chorionic gonadotropin-beta were measured by a two-site immunoenzymometric assay, and total hCG-alpha was determined by a double-antibody radioimmunoassay. Wilcoxon signed-rank and Mann-Whitney rank-sum tests were used for statistical analysis. RESULTS: Serum total human chorionic gonadotropin, total human chorionic gonadotropin-alpha, and total human chorionic gonadotropin-beta levels were significantly higher in severely preeclamptic women (p < 0.05), but not in those with mild preeclampsia, compared with those in their matched controls. CONCLUSION: Elevated serum human chorionic gonadotropin levels in severely preeclamptic women might reflect a significantly pathologic change and secretory reaction of the placenta.

Adult↗
PubMed1994

Breast cancer marker Ca549. A multicenter study.

A multicenter study of CA549, a marker for breast cancer, was conducted using sera from 1721 patients with benign and malignant conditions by an immunoradiometric assay, BRESMARQ. Acceptable assay performance was demonstrated by studies of intra-assay (2.2% to 12% coefficient of variation [CV]), interassay (4.1% to 11.8% CV), and interlaboratory (4.8% to 8.7% CV) precision; sensitivity (.3 kU/L); linearity; recovery; high-dose hook effect (up to 10,000 kU/L); and interferences (human antimouse antibodies; protein, bilirubin, hemoglobin levels; lipid and cancer therapeutic agents). A reference interval of 0-12.5 kU/L (women) and 0-11.9 kU/L (men) was established from 746 healthy persons. The distribution of values exceeding the reference range for benign conditions was as follows: pregnant and lactating women (2%); benign breast disease (5%); and seven other benign diseases, including liver (24%), lung (19%), prostate (14%), colon, endometrial, gastric, and ovarian (< 10%). For nonbreast cancers, the distribution was Hodgkin's (7%), colon (10%), endometrial (15%), gastric (15%), lymphoma (15%), prostate (20%), ovarian (39%), and liver (45%). For breast cancer, the distribution was stage I (5%), stage II (14%), stage III (32%), and stage IV (74%). The receiver-operating characteristic analysis demonstrated the usefulness of CA549 as a marker in stage IV breast cancer.

Antibodies, Monoclonal↗
PubMed1993

Comparison of intra-arterial and intravenous infusion of cisplatin for head and neck squamous cell carcinoma in a modified rat model.

To study intra-arterial infusion of chemotherapeutic agents, human squamous carcinoma cells were obtained from the FaDu cell line and were implanted in athymic rats (rnu/rnu). The xenografts were grown and then were reimplanted on a vascular pedicle and were completely isolated from the surrounding tissue. The vascular isolation of these pedicles was confirmed radiographically and histologically. After 26 days of growth, an osmotic pump was implanted to deliver either saline, intra-arterial cisplatin, or intravenous cisplatin to the vascular pedicle. Platinum levels were identified in the tumors following intra-arterial and intravenous infusions, demonstrating the usefulness of this model for delivery of antineoplastic agents. We were unable to detect differences between tumor groups for final tumor volume, tumor platinum levels, and tumor histology with the one-dose schedule used. We were able to show a remarkable uniformity of the tumor platinum levels with varying serum platinum levels with intra-arterial and intravenous infusion of cisplatin. The toxicity of each drug administration method was assessed by levels of renal platinum and rat serum creatinine and blood urea nitrogen. No differences in toxicity with the dose administrated. We believe the immunodeficient rat with a xenografted isolated vascular pedicle is an excellent model to study the effect of intra-arterial therapeutic modalities on head and neck squamous cell carcinoma.

Animals↗
PubMed1993

The Chinese General Health Questionnaire in a psychiatric setting: the development of the Chinese scaled version.

The development of the Chinese scaled GHQ-20 was based on the factor analysis of the item responses of 150 general psychiatric patients with the Chinese GHQ-60. The five subscales assessing the symptom areas of dysphoric functioning, health concern, anxious coping, sleep problems, and suicidal ideas were found to discriminate significantly the sample of patients from another sample of 653 nonpatients. As a scale, the Chinese GHQ-20 was also found to be comparable to the full Chinese GHQ-60 in screening for individuals who might benefit from psychiatric consultation. The implications for its use as a refined instrument to monitor therapeutic change of patients in different symptom areas are discussed.

Adolescent↗
PubMed1993

Elevated circulating thrombomodulin in severe preeclampsia.

A relationship between serum thrombomodulin and preeclampsia was investigated. In women with severely preeclamptic pregnancies, serum thrombomodulin levels were found to be significantly elevated as compared with those of matched control subjects (p < 0.005). Serum thrombomodulin levels correlated positively with serum creatinine (r = 0.854, p < 0.0001) and uric acid levels (r = 0.784, p < 0.001).

Adult↗
PubMed1993

Components of assertiveness: their relationships with assertive rights and depressed mood among Chinese college students in Hong Kong.

Components of assertiveness and depressive symptoms of 183 Chinese university undergraduate students were assessed in their responses to the Rathus Assertiveness Schedule and the Beck Depression Inventory. Three dimensions of assertiveness emerged: expressing, confronting and demanding responses. These components were found to relate differentially to the beliefs in specific assertive rights, although there was no evidence that nonassertive behaviors could arise from beliefs that one did not have the rights to act assertively. Nonassertive responses, especially in expressing and disclosing oneself, correlated with depressed mood. Implications for cross-cultural comparison and assertiveness training among the Chinese are discussed.

Adolescent↗
PubMed1993

The use of prostate specific antigen, clinical stage and Gleason score to predict pathological stage in men with localized prostate cancer.

Clinical stage, Gleason score and serum prostate specific antigen (PSA) levels are used separately to predict pathological stage in patients with localized prostate cancer. Because the degree of tumor differentiation has a profound influence on the expression of serum PSA, serum PSA levels alone do not reflect tumor burden accurately. To overcome this obstacle we tested these 3 variables alone and in combinations as predictors of final pathological stage in 703 men with clinically localized prostate cancer at our institution. All patients were assigned a clinical stage by 1 urologist. The Gleason score was determined from preoperative needle biopsy and serum PSA levels were measured on an ambulatory basis. Final pathological stage was determined to be either organ confined, established capsular penetration, seminal vesicle involvement or lymph node involvement. Logistic regression analysis with the likelihood ratio chi-square test determined that serum PSA, Gleason score and clinical stage all predicted final pathological stage well. The results were improved with combinations of the 3 variables (serum PSA, Gleason score and clinical stage) and the combination provided the best separation. From these analyses probability plots and nomograms have been constructed to assist urologists in the preoperative prediction of final pathological stage for patients with clinically localized prostate cancer.

Biomarkers, Tumor↗
PubMed1993

Assessing psychopathology in Chinese psychiatric patients in Hong Kong using the Brief Psychiatric Rating Scale.

This study investigated the use of the Brief Psychiatric Rating Scale (BPRS) in a sample of 155 Chinese psychiatric patients in Hong Kong. The commonly rated symptoms were those related to the spectrum of anxiety-depression, and the symptom dimensions differed only slightly from those symptom clusters reported in past studies with the BPRS. Although symptoms were rated regardless of psychiatric diagnoses, the BPRS profiles of these patients were sensitive to diagnostic distinctions. In addition, these patients were also classifiable into the 8 phenomenological types. However, the less elevated BPRS profiles across types raised the question of whether there was a tendency to under-present symptoms on the part of the patients or to under-rate symptoms on the part of the clinicians. These results were discussed in terms of the use of the BPRS for descriptive and classification studies in the Chinese setting as well as for cross-cultural research.

Adolescent↗
PubMed1993

Automation of thyroid function testing.

This article discusses the automation of thyroid function testing. The needs for automation are included in the introduction. The issues concerning automation of immunoassay are discussed, including homogeneous or heterogeneous immunoassay, competitive or immunometric assay, reagent stability, data management, sample management, signal detection, and the disadvantages of automation. Individual immunoassay systems are summarized with a table outlining the key features. Both technical and clinical performance of automated thyroid function testing are described. The article ends with a discussion of the future trends of automated immunoassay testing.

Autoanalysis↗
PubMed1992

Estimation of prostatic growth using serial prostate-specific antigen measurements in men with and without prostate disease.

Prostate growth curves were estimated from serial prostate-specific antigen (PSA) measurements on frozen sera in three groups of men: (a) 16 men with no prostatic disease by urological history and examination; (b) 20 men with a histological diagnosis of benign prostatic hyperplasia (BPH) who had undergone simple prostatectomy; and (c) 18 men with a histological diagnosis of prostate cancer. The median number of repeated PSA measurements over an 8- to 26-yr period prior to histological diagnosis or exclusion of prostate disease was eight and 11 for noncancer and cancer subjects, respectively. Predicted rates of change in PSA (PSA velocity) were linear and curvilinear for control and BPH subjects, respectively. Subjects with cancer demonstrated both a linear and an exponential phase of PSA velocity. Based on time to double PSA, we estimated the epithelial doubling time for men without prostate disease to range from 54 +/- 13 yr at age 40 to 84 +/- 13 yr at age 70. For men with BPH, doubling times ranged from 2 +/- 13 yr at age 40 to 17 +/- 5 yr at age 85. Subjects with local/regional and advanced/metastatic cancer had similar PSA doubling times of 2.4 +/- 0.6 yr and 1.8 +/- 0.2 yr, respectively. These data are consistent with what is known about prostatic growth with age in men without prostate disease and BPH, and the kinetics of prostate cancer growth. Estimates of prostatic growth rate from changes in PSA may be useful clinically in management of men with prostate disease.

Aged↗
PubMed1992

Hepatitis B and hepatitis C in emergency department patients.

BACKGROUND: Infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and the human immunodeficiency virus type 1 (HIV-1) are common in inner-city populations, but their frequency and interrelations are not well established. METHODS: During a six-week period, excess serum samples were collected, along with information on risk factors, from all adult patients presenting to an inner-city emergency department. The samples were assayed for hepatitis B surface antigen (HBsAg) and antibodies to HCV and HIV-1. RESULTS: Of the 2523 patients tested, 612 (24 percent) were infected with at least one of the three viruses. Five percent were seropositive for HBV, 18 percent for HCV, and 6 percent for HIV-1. HCV was found in 145 of the 175 intravenous drug users (83 percent), 36 of the 171 transfusion recipients (21 percent), and 5 of the 24 homosexual men (21 percent). Among black men 35 to 44 years of age, the seroprevalence of HCV was 51 percent. HBsAg was present in 9 percent of those whose only identifiable risk was possible heterosexual exposure. At least one viral marker was found in about 30 percent of the patients who were actively bleeding or in whom procedures were performed. Testing for HIV-1 alone would have failed to identify 87 percent of the patients infected with HBV and 80 percent of those infected with HCV. CONCLUSIONS: In a population of patients in an inner-city emergency room, HBV, HCV, and HIV-1 are all highly prevalent. However, routine screening for HIV-1 alone would identify only a small fraction of the patients who pose risks of severe viral infections, including HBV and HCV, to providers.

Adolescent↗
PubMed1992

Coping with depressed mood among Chinese medical students in Hong Kong.

Depressed mood and coping activities were assessed in a sample of 95 undergraduate medical students using the Beck Depression Inventory and the Coping Strategies Scales. Problem-focused activities were commonly employed by students and were perceived as helpful although activities involving brooding over problems, perceived as less helpful, were also commonly employed. There were few sex differences in employment of specific activities. In terms of coping strategies, depressed students tended to avoid and deny problems and contain their emotions, and depressed females in particular were more passive. It is suggested that while depressed and nondepressed students equally employed apparently adaptive strategies such as problem-solving and cognitive restructuring, the effectiveness of these strategies could be undermined by depressed students' brooding over problems and passivity.

Adaptation, Psychological↗
PubMed1992

The value of serum enzymatic acid phosphatase in the staging of localized prostate cancer.

With the development of reliable assays for the measurement of prostate specific antigen (PSA), the use of serum enzymatic acid phosphatase in the staging of disease before radical prostatectomy has been called into question. We evaluated 460 consecutive men who were referred to our institution as candidates for radical prostatectomy. Staging evaluation included digital rectal examination, serum measurements of enzymatic acid phosphatase and PSA, bone scans and, in patients in whom advanced clinical stage was anticipated, computerized tomography, magnetic resonance imaging or transrectal ultrasonography. Of the 460 men 21 (4.6%) had elevations of serum enzymatic acid phosphatase. All 19 men with elevations who were fully evaluated proved to have either positive bone scans, extraprostatic extension of disease, PSA greater than 100 ng./ml., positive lymph nodes or positive seminal vesicles. However, in 17 of the 21 men (81%) with elevated serum enzymatic acid phosphatase advanced disease was detected by either abnormal digital rectal examination or PSA alone. Thus, serum enzymatic acid phosphatase provided unique information in only 4 of the entire study population (0.9%). Recognizing this low yield of unique information, we believe that measurements of serum enzymatic acid phosphatase are no longer mandatory before radical prostatectomy but may provide important confirmatory information in patients in whom advanced disease is suspected.

Acid Phosphatase↗