Biomedical subjects

A S Chang

Publications and source records attributed to A S Chang.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Epidemiologic characteristics and multiple risk factors of lung cancer in Taiwan.

The specific aim of this study was to examine epidemiologic characteristics and multiple risk factors of lung cancer in Taiwan. The age-adjusted mortality from lung cancer has been increasing since the early 1950s with a constant male-to-female ratio of around 2.0. International comparison of cumulative mortality from lung cancer showed a much lower male-to-female ratio in Chinese than in other populations. Significantly high mortality from lung cancer was observed in highly urbanized cities and the endemic area of chronic arsenicism in Taiwan. Significant associations of active and passive cigarette smoking with epidermoid carcinoma, small cell carcinoma and adenocarcinoma of the lung were observed in a hospital-based case-control study carried out in Taipei metropolitan areas. Alcohol drinking, coffee drinking and various types of indoor air pollution were not related to lung cancer after the cigarette smoking habit was adjusted through a multiple logistic regression analysis.

Adolescent↗

PubMedDate not supplied

Human leukocyte antigen (HLA) frequency among patients with nasopharyngeal carcinoma in Taiwan.

In order to assess the association between human leukocyte antigens (HLA) and nasopharyngeal carcinoma (NPC), a total of 10 familial and 10 sporadic NPC patients and 171 unrelated healthy controls were studied. HLA typing was performed using commercial trays which defined 30 specificities of HLA-A, B and C loci and 10 specificities of HLA-D locus according to the method of Tiwari and Terasaki. HLA-A2, B16 and DR1 were found to be higher among patients with NPC than unrelated healthy controls with an odds ratio (OR) and a 95% confidence interval of 5.91 (2.1-16.6), 6.00 (2.0-18.0) and 6.89 (1.3-37.5), respectively. Further analysis showed that A2(+) B16(+) haplotype was significantly associated with a much higher risk of NPC (OR = 15.5) as compared with A2(-) B16(-) haplotype. No difference in frequency distributions of HLA-A, B, C and D antigens was observed between familial and sporadic NPC patients.

Adult↗

PubMedDate not supplied

Appraisals of bereavement, coping, resources, and psychosocial health dysfunction in widows and widowers.

The purpose of the study was to test a model, based on Lazarus and Folkman's (1984) stress-coping framework, on widowed persons' psychosocial health dysfunction after conjugal bereavement. Older widows (n = 100) and widowers (n = 59) were identified through church burial records and interviewed using the Ways of Coping Checklist, Sickness Impact Profile, and questionnaires to assess appraisal of bereavement and resources. Path analysis indicated that lower threat appraisal, more problem-focused and less emotion-focused coping, greater resource strength, and younger age had direct effects on reducing psychosocial health dysfunction, explaining 30% of the variance. Higher threat appraisal influenced the use of more problem- and emotion-focused coping strategies. Greater resource strength directly influenced lower threat appraisal. Sex and type of death affected psychosocial health dysfunction through their effect on resource strength.

Adaptation, Psychological↗

PubMedDate not supplied

Lumbosacral radiculopathy screen. Optimizing the number of muscles studies.

The literature is unclear as to which muscles and how many are required for a sensitive lumbosacral radiculopathy (LSR) screen. A retrospective study of 247 electrodiagnostically confirmed LSRs in 201 patients over a 3-yr period was conducted to determine how many muscles were required to identify a LSR. All LSRs showed abnormal spontaneous activity (positive waves or fibrillation potentials) in two or more muscles innervated by the same nerve root level but different peripheral nerves. All cases were categorized by radiculopathy level, and the most frequently abnormal individual muscles were combined into different muscle screens. The frequency with which each muscle screen identified a radiculopathy was the frequency with which one or more muscles in the screen displayed abnormal spontaneous activity divided by the total number of radiculopathies. The paraspinal muscles (PM) alone identified 88% of LSRs. Without PM, two muscle screens identified only 14-68%, three muscle screens identified 37-89% and four muscle screens identified 45-92%. Including PM, three muscle screens identified 86-94% of LSRs, four muscle screens identified 91-97% and five muscle screens yielded 94-98% identification. Seven to ten muscle screens resulted in minimal improvements in identifying a LSR with 98-99% identification. We conclude that five muscle LSR screens, including PM, are sufficient to identify LSRs while minimizing patient discomfort and examiner time.

Adolescent↗

PubMedDate not supplied

A pharmacokinetic study of phenylcyclohexyldiethylamine. An analog of phencyclidine.

The pharmacokinetics of three phencyclidine analogs--phenylcyclohexyl-diethylamine (PCDE), phenylcyclohexylethylamine (PCE), and phenylcyclohexylamine (PCA)--were determined in rats after intravenous administration of each drug. Because PCE and PCA are major metabolites of PCDE, their plasma levels were also measured after administration of PCDE. Similarly, PCA concentrations was determined after administration of PCE. The data were combined and analyzed by nonlinear regression procedures using compartmental and noncompartmental models to determine the kinetic parameters of PCDE metabolism. The object was to estimate the kinetic constants for the metabolic sequence, PCDE to PCE to PCA. A 6-compartment model (two pools for each analyte) that included saturable components for the conversion of PCDE to PCE and PCE to PCA gave the best fit to the combined data. Despite large uncertainties for some microparameters, useful estimates were obtained for clearances, distribution volumes, and fraction of PCDE or PCE converted to PCE and PCA in vivo under nonsaturating conditions. The estimated fraction of PCDE converted to PCA and the apparent Km value for the conversion of PCDE to PCE were comparable to values obtained in vitro with microsomal preparations, suggesting that metabolic studies in vitro provide reasonable predictors of the biotransformation process in vivo for this class of compounds.

Animals↗