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Biomedical subjects

J D Wang

Publications and source records attributed to J D Wang.

At least 55 records · Page 3Linked to original sources
PubMed1999

Relationship of blood lead levels to personal hygiene habits in lead battery workers: Taiwan, 1991-1997.

BACKGROUND: The blood lead concentrations of workers in lead battery factories are more than 4 times higher than those of the general population in Taiwan. Therefore, efforts are needed to reduce lead exposure in this high-risk population. A health promotion program on personal habits that reduce lead exposure has been carried out in a lead battery factory since 1991. This study investigated the longitudinal relationship of workers' blood lead concentrations and personal hygiene habits from 1991 through 1997. METHODS: In each of the 7 years of the study, occupational physicians questioned workers regarding nine personal hygiene items, personal information, and medical history before their annual health examination. The relationship between blood lead concentrations and personal hygiene habits was analyzed by longitudinal multiple regression in a mixed effect model with adjustment for potential confounders. In addition, the risk ratio of a blood lead concentration exceeding 40 micrograms/dL in men and 30 micrograms/dL in women (the action levels set by the Department of Health, Taiwan) was estimated by generalized estimating equations. RESULTS: Blood lead levels decreased significantly in the first 5 years of the study. The personal habits most closely related to blood lead concentrations were smoking at work sites (estimated coefficient = 3.13, P < 0.001), and eating at work sites (estimated coefficient = 1.38, P = 0.069). The risk ratio for workers with both these habits exceeding the action level of blood lead was 2.93 (95% CI 1.27-6.77). Difference in job titles, however, accounted for a major portion of the variance in blood lead. For example, working in "pasting" and "plate-cutting" was associated with blood lead elevations > 20 micrograms/dL in comparison to the "low- or no-exposure jobs." CONCLUSIONS: Health promotion programs can decrease exposure of lead workers; reducing the practices of smoking and eating at work sites should be the core of such programs. However, a major reduction in lead exposure for some jobs (e.g., "pasting" and "plate cutting") in lead battery factories in Taiwan is unlikely to occur without major engineering changes.

Feeding Behavior↗
PubMed1999

Estimation of expected utility gained from the helmet law in Taiwan by quality-adjusted survival time.

The objective of this study was to empirically estimate the expected utility gained from the implementation of the 1997 helmet law in Taiwan by using quality-adjusted survival time (QAST). We randomly selected 400 out of 8221 registered cases of head injury and successfully interviewed 99 cases with the index of health-related quality of life (IHRQ). The function of IHRQ was then multiplied with the corresponding survival function to obtain the QAST for head injury. The total utility gained from the helmet law in Taipei within 1 year was estimated by multiplying the expected loss of utility per patient with the number of prevented cases. The results showed that after 80 months of follow-up, the QAST of the injured population was 66.3 quality-adjusted life-months (QALMs), while that of the reference population was 78.7 QALMs. We extrapolated the QAST for total life expectancy by simulating the survival of head injury cases using the life table data from the general population. The life-long utility loss of a head injury case was found to be 4.8 quality-adjusted life-years (QALY). The number of prevented cases during the first year of enforcement of the helmet law was estimated to be 1300 cases in Taipei, which amounted to 6240 QALYs gained. For lack of data, we were unable to calculate the possible gain from helmet on reduction of severity among nonfatal cases with head injury, and the estimation was only a lower bound. We concluded that the QAST approach is a feasible approach applicable to health policy decision-making, especially in cost-utility analysis.

Accidents, Traffic↗
PubMed1999

Plasma p53 protein and anti-p53 antibody expression in vinyl chloride monomer workers in Taiwan.

Vinyl chloride (VC) workers are known to be at risk for development of angiosarcoma of the liver (ASL), a rare tumor. Previously, a study of p53 gene mutations in tumors of VC-exposed workers found that 50% of liver angiosarcomas contained such mutations. Mutant p53 oncoprotein and anti-p53 antibodies can also be found in the sera of ASL patients and VC-exposed workers without cancer. Workers in Taiwan have also been exposed to VC, and some have contracted liver tumors. In this study, we used enzyme-linked immunosorbent assays to detect mutant p53 protein and anti-p53 antibodies in the plasma of VC-exposed workers in Taiwan. Thirty-three of 251 (13.2%) VC-workers tested positive for the p53 overexpression (10% with positive mutant p53 protein and 3.6% with positive anti-p53) in their plasma, but only 2 of 36 controls (5.6%) tested positive (2.8% with positive mutant p53 protein and 2.8% with positive anti-p53). There was a significant association between cumulative VC exposure concentration and positive p53 expression (P = 0.032) among VC workers after we adjusted for age, hepatitis, drinking, and smoking status. In summary, P53 overexpression (mutant p53 protein or anti-p53 antibody) can be found in the plasma of VC workers in Taiwan, and a significant dose-response relationship exists between plasma p53 overexpression and VC cumulative exposure concentration.

Adult↗
PubMed1999

Pregnane glycosides, gymnepregosides G-Q from the roots of Gymnema alternifolium.

The structural elucidation of eleven new related polyoxypregnane glycosides, gymnepregosides G (1), H (2), I (3), J (4), K (5), L (6), M (7), N (8), O (9), P (10) and Q (11), from the roots of Gymnema alternifolium (Asclepiadaceae) was achieved by a detailed study of 1H- and 13C-NMR spectral data and chemical means. The results obtained for new compounds, 1-11, show that they are (20S)-pregn-6-ene-3 beta,5 alpha,8 beta,12 beta,14 beta,17 beta,20-heptaol 3-O-glycosides, and all the sugars at C-3 are beta(i-->4)-linked. Some of them possess benzoyl, (E)- and (Z)-cin-namoyl, and tigloyl residues as the ester linkages located at C-12 and/or C-20 of the aglycone.

Carbohydrate Sequence↗
PubMed1999

Short-term effect of ozone on the pulmonary function of children in primary school.

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter < or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations < 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.

Adolescent↗
PubMed1999

Inhibition of DNA synthesis in isolated human endometrial cells by a levonorgestrel-releasing intrauterine device.

OBJECTIVE: To estimate the effect of an intrauterine device (IUD) releasing 20 micrograms levonorgestrel (LNG) per 24 hours on DNA synthesis in human endometrial cells before and after 12 months of use. STUDY DESIGN: Endometrial specimens were collected from the anterior or posterior wall of the miduterus from 6 females on cycle day 10-12 before insertion of the IUD and after 12 months of use. RESULTS: Previous results from our group did not reveal any influence on endometrial DNA cell content when a levonorgestrel IUD releasing 2 micrograms/24 h was used for 12 months in a group of fertile females. In this study, the IUD release rate, 20 micrograms LNG/24 h, was statistically significantly different from the results in the previous studies. The effect of the levonorgestrel IUD on endometrial proliferation was dose dependent, and a significant correlation could be found between continuous exposure to LNG and inhibition of DNA synthesis in endometrial cells. CONCLUSION: Inhibition of proliferative activity in endometrial cells seems to be reflected by a decrease in DNA synthesis per cell nucleus and contributes to the clinical performance of the LNG-releasing IUD.

Adult↗
PubMed1998

Effects on sister chromatid exchange frequency of aldehyde dehydrogenase 2 genotype and smoking in vinyl chloride workers.

Vinyl chloride monomer (VCM) is a human carcinogen. However, the exact mechanism of carcinogenesis remains unclear. VCM may be metabolized by cytochrome P450 2E1 (CYP2E1), aldehyde dehydrogenase 2 (ALDH2) and glutathione S-transferases (GSTs). Thus workers with inherited variant metabolic enzyme activities may have an altered risk of genotoxicity. This study was designed to investigate which risk factors might affect sister chromatid exchange (SCE) frequency in polyvinyl chloride (PVC) workers. Study subjects were 44 male workers from three PVC factories. Questionnaires were administered to obtain detailed histories of cigarette smoking, alcohol consumption, occupations, and medications. SCE frequency in peripheral lymphocytes was determined using a standardized method, and CYP2E1, GSTM1, GSTT1 and ALDH2 genotypes were identified by the polymerase chain reaction (PCR). Analysis revealed that smoking status and exposure to VCM were significantly associated with increased SCE frequency. The presence of ALDH2 1-2/2-2 genotypes was also significantly associated with an elevation of SCE frequency (9. 5 vs. 8.1, p<0.01). However, CYP2E1, GSTM1 or GSTT1 genotypes were not significantly associated with SCE frequency. When various genotypes were considered together, combination of CYP2E1 c1c2/c2c2 with ALDH2 1-2/2-2 showed an additive effect on SCE frequency. Similar results were also found for the combination of smoking with CYP2E1, or smoking with ALDH2. These results suggest that VCM workers with ALDH2 1-2/2-2 genotypes, who also smoke, may have increased risk of DNA damage.

Adult↗
PubMed1998

GroEL-GroES-mediated protein folding requires an intact central cavity.

The chaperonin GroEL is an oligomeric double ring structure that, together with the cochaperonin GroES, assists protein folding. Biochemical analyses indicate that folding occurs in a cis ternary complex in which substrate is sequestered within the GroEL central cavity underneath GroES. Recently, however, studies of GroEL "minichaperones" containing only the apical substrate binding subdomain have questioned the functional importance of substrate encapsulation within GroEL-GroES complexes. Minichaperones were reported to assist folding despite the fact that they are monomeric and therefore cannot form a central cavity. Here we compare directly the folding activity of minichaperones with that of the full GroEL-GroES system. In agreement with earlier studies, minichaperones assist folding of some proteins. However, this effect is observed only under conditions where substantial spontaneous folding is also observed and is indistinguishable from that resulting from addition of the nonchaperone protein alpha-casein. By contrast, the full GroE system efficiently promotes folding of several substrates under conditions where essentially no spontaneous folding is observed. These data argue that the full GroEL folding activity requires the intact GroEL-GroES complex, and in light of previous studies, underscore the importance of substrate encapsulation for providing a folding environment distinct from the bulk solution.

Base Sequence↗
PubMed1998

Estimates of cancer risk from chloroform exposure during showering in Taiwan.

The purpose of this study was to compare the cancer risk with chloroform exposure during showering. The study concentrated on the three major metropolitan areas of Taiwan. Total exposure was measured based on a combination of ingestion, inhalation and skin absorption. A total of 137 tap water samples were taken from 26 locations within the Taipei (north), Taichung (central) and Kaohsiung (south) areas. Analysis of VOC compounds was performed according to the US EPA Method 524. Chloroform concentrations were highest in Kaohsiung (60.19 micrograms/l), followed by Taipei (18.83 micrograms/l) and Taichung (17.55 micrograms/l). Based on the two-resistance theory to volatilization in showers, when air flow rate is increased, chloroform concentrations in the air significantly decrease. A 10-min shower would result in chloroform exposure with a 3:4:3 ratio (ingestion, inhalation, skin absorption). However, that changes to 1:7:2 for a 20-min shower under the same conditions. The cancer risk was highest in Kaohsiung at 17.59 per million for a 10-min shower and 64.77 per million for a 20-min shower. The lowest cancer risk was found in Taichung at 4.99 and 11.50 per million for a 10- and 20-min shower, respectively. Although ingestion is commonly considered to be the primary source of exposure to chloroform from tap water, inhalation and skin absorption exposure concentrations were found to be even higher.

Administration, Inhalation↗
PubMed1998

Respiratory symptoms of primary school children living in a petrochemical polluted area in Taiwan.

In 1994-1995 a cross-sectional epidemiological study investigating the respiratory health of school children in two Taiwan areas was conducted; one area was located in a region with petrochemical manufacturing complexes (Linyuan), and the other was situated in a reference area with no local industrial emissions (Taihsi). All primary school children residing in the two areas were involved in the study. Four hundred seventy children were studied in the area with high exposure to industrial emissions, and 611 children lived in the reference area. Respiratory health was assessed by evaluation of the children's respiratory symptoms and illnesses, using a parent-completed questionnaire. Particulates, sulfur dioxide (SO2), nitrogen dioxide (NO2), and acid aerosols levels were significantly higher in the exposed area than in the reference area. The school children in the petrochemical area had significantly more upper respiratory symptoms and asthma compared with the children living in the control area. Although the association with known petrochemical air pollution is suggestive, this cross-sectional study cannot confirm a causal relation and further studies are needed.

Air Pollutants↗
PubMed1998

Lymphotactin: a key regulator of lymphocyte trafficking during acute graft rejection.

The attraction of leucocytes to allografts is essential for rejection. The process is controlled by chemokines. In order to clarify the role of lymphotactin (a cytokine that represents a novel branch of the chemokine superfamily) in regulating leucocyte trafficking during graft rejection, we used rat renal transplantation models to examine its gene expression and the distribution of lymphotactin-expressing cells in renal grafts. Lymphotactin mRNA was upregulated strongly in acutely rejecting renal allografts. The mRNA was undetectable in isografts, chronically rejecting renal allografts or normal kidney. Once lymphotactin was expressed, large numbers of infiltrating lymphocytes were seen. Moreover extended studies demonstrated that in cultured rat spleen cells the expression of lymphotactin mRNA was markedly induced by phytohaemagglutinin (PHA) or phorbol myristate acetate (PMA), and such induction was inhibited by the immunosuppressive drugs FK506 and cyclosporin. Collectively, these observations provide new evidence demonstrating that lymphotactin is a key regulator of lymphocyte motility and adhesiveness during acute allograft rejection. FK506 and cyclosporin inhibition of lymphotactin expression is likely to represent an important molecular mechanism of the action of the drugs.

Acute Disease↗