Rapid and simultaneous determination of mycophenolic acid and its glucuronide conjugate in human plasma by ion-pair reversed-phase high-performance liquid chromatography using isocratic elution

A high-performance liquid chromatographic method has been developed for the simultaneous determination of mycophenolic acid (MPA) and its glucuronide conjugate (MPAG) in human plasma. The method involves protein precipitation with acetonitrile, followed by ion-pair reversed-phase chromatography on C18 column, with a 40 mM tetrabutyl ammonium bromide (TBA)-acetonitrile (65:35, v/v) mobile phase. A 20-microl volume of clear supernatant was injected after centrifugation, and the eluent was monitored at 304 nm. No interference was found either with endogenous substances or with many concurrently used drugs, indicating a good selectivity for the procedure. Calibration curves were linear over a concentration range of 0.5-20.0 microg/ml for MPA and 5-200 microg/ml for MPAG. The accuracy of the method is good, that is, the relative error is below 5%. The intra- and inter-day reproducibility of the analytical method is adequate with relative statistical deviations of 6% or below. The limits of quantification for MPA and MPAG were lower than 0.5 and 5.0 microg/ml, respectively, using 50 microl of plasma. The method was used to determine the pharmacokinetic parameters of MPA and MPAG following oral administration in a patient with renal transplantation.

[Sensitive and rapid analysis of nitrophenols and herbicides by capillary zone electrophoresis (CZE)]

11 Nitrophenols and some acidic herbicides have been separated by modified CZE. Good separation of such compounds can be achieved in less than 10 min by simply modifying the run buffer with organic solvents such as methanol, acetonitrile in a concentration of 40% (V/V). The limits of detection (LODs) for nitrophenols by UV-absorption at 215 nm were 0.5 mg/L-1.1 mg/L. Solid phase extraction was used to preconcentrate nitrophenols and some herbicides to reach an LOD at microgram/L levels. Typical samples have been analyzed.

Differences in binding of glucocorticoid receptor to DNA in chronic renal graft rejection

Although chronic rejection is the most common reason for late allograft loss, its pathophysiology and etiology are unclear. Attempts to prevent chronic rejection are now focused on the modulation of transcriptional regulation. We evaluated the ability of glucocorticoid receptors (GR) to bind to the DNA binding site in peripheral blood mononuclear cells (PBMC) of five patients with chronic rejection and seven without it. Using an electrophoretic mobility shift assay, we measured the amount of nuclear glucocorticoid receptor capable of binding to its specific DNA recognition sequences, termed glucocorticoid response elements (GRE). GR binding was significantly greater in control patients than in those with chronic rejection (P < 0.01). The retarded band was almost undetectable in two patients with chronic rejection even though they were taking more prednisolone than the seven control patients, all of whom had clearly identifiable retarded bands. These results suggest a decreased ability of GR to bind to GRE in chronic rejection, resulting in a reduced ability to block key proinflammatory promoter sites. This reduced binding may be one molecular basis of chronic rejection.

Rapid and simple determination of mycophenolic acid in human plasma by ion-pair RP-LC with fluorescence detection

Mycophenolic acid (MPA) is an immunosuppressive drug given as the prodrug of mycophenolate mofetil (MMF). In order to investigate the pharmacokinetics of MPA, a simple, specific, sensitive and reliable method has been established for the quantitative determination of MPA in plasma from renal transplant recipients. The method involves a single-step protein precipitation procedure and a specific determination by ion-pair reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. Separation was achieved on a C18 column (150 x 4.6 mm, 5 microm) with a mobile phase composed of borate buffer (pH 10.0; 50 mM)--acetonitrile--tetrabutylammonium bromide (200 mM) (75:25:1, v/v/v). The fluorescence detector was set at 310 (excitation) and 430 nm (emission). Following protein precipitation with ice-cold acetonitrile, clear supernatants (50 microl) were injected into the HPLC system. The retention time of MPA was approximately 4.5 min. The HPLC run time was 8 min. The assay was linear in concentration range 0.2-20.0 microg/ml for MPA in human plasma. Precision of the assay in the concentration range examined was from 0.89 to 3.21% for the intra-assay run and from 3.01 to 4.35% for the inter-assay run. A limit of detection was 0.05 microg/ml at a signal-to-noise ratio of 3. This validated method was then applied to the determination of MPA concentrations in renal transplant recipients after oral administration of 0.75 g of MMF.

Chronic cyclosporin-induced nephropathy

AIMS

There is still no consensus about the prognostic influence of chronic nephropathy induced by low-dose maintenance therapy with cyclosporin. Our aim was to investigate the prognostic effect of cyclosporin nephropathy in Japanese renal transplant recipients.

MATERIAL

We retrospectively investigated the clinical records of 1,323 kidney transplant recipients who received cyclosporin at 65 institutions in Japan from 1982 to 1991.

METHOD

Renal biopsy was performed in 461 patients.

RESULTS

At 5 years and 9 years after transplantation, the patients who had cyclosporin nephropathy associated with immunological rejection, glomerulonephritis, or both showed a significantly worse prognosis than those with cyclosporin nephropathy alone (p < 0.01). There was no significant difference in the loss of renal function at 9 years after transplantation between patients showing no abnormalities and patients with cyclosporin nephropathy alone. Even when cyclosporin nephropathy was absent, the long-term prognosis was unfavorable in recipients with immunological rejection or glomerulonephritis.

CONCLUSIONS

These results suggest that cyclosporin nephropathy does not influence the prognosis of renal transplantation in patients on low-dose maintenance therapy with cyclosporin.

A simple self-rating assessment method of residual work capability for occupational permanent disabilities

BACKGROUND

To explore the validity, reliability, and determinants of a simple self-rating assessment method of residual work capability (RWC) after occupational permanent disabilities.

METHODS

Five hundred and thirty-nine compensated permanent disability workers answered three consecutive visual analogue questionnaires wherein they self-rated their residual work capability in terms of speed (RWCS), quality (RWCQ) and a combination of speed and quality (RWCC). At two major hospitals in Taiwan, 169 of these subjects were evaluated with physical capacity assessment (PCA), cognition and sensation assessment (CSA), the work ability index (WAI), and the 12-item Chinese health questionnaire (CHQ-12).

RESULTS

High test-retest reliability (Pearson's correlation coefficient 0.77) and satisfactory concurrent validity were shown for RWCS and RWCC. All PCA, CSA and WAI showed significant correlation with RWCs, while CHQ-12 displayed borderline correlation. Employment status after injury and status of the victim's salary as the main source of income for his/her family before injury, were the major determinants of RWCs, in addition to the scales of PCA, CSA and WAI.

CONCLUSIONS

The RWCC resulting from the self-rating method may be used as a simple assessment of a victim's residual work capability after occupational permanent disabilities.

[Renovascular hypertension]

Renovascular disease is one of the most common causes of secondary hypertension. Recent technical advances have changed the management principles, which include a more aggressive approach to the diagnosis and treatment of renovascular hypertension (RVH). We experienced a total of 95 cases with RVH between 1958 and 1999. The mean age of all patients was 31.8 years old, ranging from 3 to 64 years. The three major basal diseases that caused RVH were fibromuscular dysplasia (34/95), arteriosclerosis (26/95), and aortitis (12/95). Ninety-two kidneys were treated in 79 of the 95 patients. The major therapeutic modalities performed were reconstruction of renal artery (6/79), nephrectomy (21/79), autotransplantation (26/79), and percutaneous transluminal angioplasty (PTA) (25/79). PTA is now the treatment of choice for the initial management of patients with RVH. Surgical treatment is generally reserved for patients in whom PTA fails. Pharmacotherapy is used on patients awaiting angioplasty or revascularization, those who are too ill for intervention, and those who have failed to respond to intervention.

Vibration perception thresholds in workers with long term exposure to lead

OBJECTIVES

To evaluate the impact of long term occupational exposure to lead on function of the peripheral nervous system as reflected by vibration perception threshold (VPT), measured with a portable vibrameter.

METHODS

217 Workers in a lead battery factory were required to have an annual blood lead measurement during each of the 5 years preceding this study. All were invited to take the VPT test. A total of 206 workers were studied. The associations were analysed between VPTs and current blood lead concentration, mean concentration of blood lead over the past 5 years, maximum blood lead concentration during the past 5 years, index of cumulative blood lead (ICL), time weighted index of cumulative blood lead (TWICL), and percentage of lifespan spent at work in the plant, as well as the other potential confounders. Ordinary multiple regressions, generalised additive models, and hockey stick regression analyses were used to explore the potential existence of a threshold effect of blood lead variables on VPT.

RESULTS

VPT at a frequency of 220 Hz ranged from 6 to 100 (10(-2) g, or 0.098 m/s(2)) with a mean (SD) of 19.8 (14.2) for the feet and from 4 to 43 with a mean (SD) of 10.2 (6.1) for the hands. The five variables of exposure to lead were all significantly correlated with VPT of the feet but not the hands. In multiple linear regression analyses, the mean of the blood lead concentrations and the TWICL were significantly associated with VPT of the feet. The relation between VPT of the feet and mean blood lead was shown to be a J shaped curve with a generalised additive model and local smoothing technique. In the hockey stick regression, evidence was found of a threshold effect at a mean blood lead concentration of 31 microgram/dl. Above this threshold it was estimated that each increase of 1 microgram/dl mean blood lead over 5 years would increase VPT of the feet by 0.29 (10(-2) g) or 0.028 m/s(2) (at a frequency of 220 Hz) with other potential confounders held constant.

CONCLUSION

This study suggests that measurement of vibration sensory threshold is a relatively effective tool for detecting lead neuropathy in field studies, and that lead might cause sensory neuropathy with an effect threshold corresponding to a 5 year mean blood lead concentration of 31 microgram/dl.

Dimethylacetamide, ethylenediamine, and diphenylmethane diisocyanate poisoning manifest as acute psychosis and pulmonary edema: treatment with hemoperfusion

CASE REPORT

A 27-year-old man, employed by a synthetic fiber company, had been exposed to dimethylacetamide, ethylenediamine, and diphenylmethane diisocyanate in a confined space continuously for 4-6 hours per day for 3 days before admission. Hallucinations and delusions were noted at admission; pulmonary edema developed subsequently. The electroencephalogram showed diffuse moderate cortical dysfunction and slow waves at 4-7 Hz, 20-80 microV. Seizures, liver injury, and rhabdomyolysis were noted on the 4th hospital day. The patient was treated by hemoperfusion with a decrease in urine dimethylacetamide from 3,265 mg/g to 4 mg/g creatinine over 4 days. Serial urinary dimethylacetamide and electroencephalogram correlated with the clinical condition.

[Recent advances of silica packing in high performance liquid chromatography]

Developments of silica packings in high performance liquid chromatography are reviewed with 65 references. Preparative and modification methods of silica packings are introduced. The physical characterization on silica surface is elucidated. The applications of silica packings in HPLC are outlined and the trends of silica packings in China are described.

Subject-domain approach to the study of air pollution effects on schoolchildren's illness absence

In this paper, the authors propose a new statistical modeling technique, the subject-domain approach, which is theoretically proven to be equivalent to the time-domain approach in detecting an association between exposure and response with time trends. The authors use an empirical data set from a school absence monitoring study conducted during the 1994-1995 school year in Taiwan to demonstrate this subject-domain approach's application to environmental epidemiologic studies. Because the subject-domain models can control the influential personal confounding factors in the models, they show greater statistical power than the traditional time-domain approaches in determining the relation between air pollution and illness absences. The authors' models found that the schoolchildren's risks of illness absence were significantly related to acute exposures to nitrogen dioxide and nitrogen oxides with a 1-day lag (p < 0.01) at levels below the World Health Organization's guidelines. By contrast, the authors could not detect significant associations between air pollution and schoolchildren's absenteeism using time-domain approaches. Such findings imply that the models built on subject domain may be a general solution to the problem of the ecologic fallacy, which is commonly encountered in environmental and social epidemiologic studies.

Mother's willingness to pay for her own and her child's health: a contingent valuation study in Taiwan

We use the contingent valuation (CV) method to estimate mothers' willingness to pay (WTP) to protect themselves and their children from suffering a minor illness-a cold-in Taiwan. WTP is specified as a hedonic function of the duration and severity of the cold (measured alternatively by symptoms experienced and the Quality of Well-Being (QWB) index) and of respondents' socioeconomic characteristics. The average mother is willing to pay more to protect her child than herself from suffering a cold. Median WTP to avoid the average mother's and child's colds are US$37 and US$57, respectively. Adjusting for the greater duration and severity of the average mother's cold suggests that WTP to prevent comparable illnesses is approximately twice as large for the child as for the mother. We also find that mother's WTP is about 20% greater to prevent a son's than a daughter's illness.

Diagnosis and monetary quantification of occupational injuries by indices related to human capital loss: analysis of a steel company as an illustration

Prevention of occupational injuries is an important task of human resource management. In this study, new indices of human capital loss of occupational injury including cumulative injury rate, proportion of potential workdays lost, and potential salary lost were applied to the analysis of registry data of occupational injuries from 1986 to 1994 of a steel company in Taiwan. In addition, we compared these indices with disabling frequency rate and severity rate. The results showed that the average disabling frequency rate and cumulative injury rate of the whole company were 4.12 and 0.41, respectively; and the average disabling severity rate and proportion of potential workdays lost of the whole company were 563 and 229 x 10(-6), respectively, during 1986-1994. There was no consistent improvement in occupational safety in this period. The average potential salary lost of the whole company was more than US$ 2 million per year with a discount rate of 0.04, which was equivalent to 92 times of average annual income of a worker. The major monetary loss were due to non-traffic injuries of operators and traffic injuries of non-operators, which amounted to US$ 145 and 152 per person per year. As the new indices can provide additional information on lifetime occupational risk and human capital loss in monetary values, we concluded that they may be useful supplementary tools for monitoring and analyzing occupational injury data in a company.

New affinity nylon membrane used for adsorption of gamma-globulin

Microporous polyamide membranes were first modified by acid hydrolysis and subsequently bound with hydroxy-ethylcellulose to amplify reactive groups and reduce nonspecific interactions with proteins. Then 1,6-diaminohexane as space arm and phenylalanine as ligand were immobilized onto the nylon membranes by s-triazine trichloride activation. Affinity membranes thus obtained were set in a stack and used to adsorb gamma-globulin. The adsorption capacity (qm) of the affinity membrane is 53 micro gamma-globulin per m2 membrane and the desorption constant (Kd) is 2.35 x 10(-6) mol/l. The effects of feed, washing and elution rates on adsorption and desorption behavior were investigated. The results showed that affinity purification through these membranes could not be operated at very high flow-rates. A stack of 20 membranes with 47 mm diameter can adsorb 7.8 mg gamma-globulin with a purity of 91.6% from 4 ml of human plasma in a single-pass mode.

Oligosaccharides from Hoya carnosa

Oligosaccharides A, B, and C (1-3, respectively) were isolated from the stem of Hoya carnosa. Their structures were established by NMR and chemical methods. Compounds 1 and 2 were 6-deoxy-3-O-methyl-beta-allopyranosyl(1-->4)-beta-cymaropyranosyl( 1-- >4)-beta-cymaropyranosyl(1-->4)-beta-cymaronic acid delta-lactone and 6-deoxy-3-O-methyl-beta-allopyranosyl(1-->4)-beta-oleandropyranosyl++ +(1 -->4)-beta-cymaropyranosyl(1-->4)-beta-cymaronic acid delta-lactone, respectively. Compound 3 was the sodium salt of 2.

Plaque pH and associated parameters in relation to caries

Intensified plaque acidogenicity in caries-prone subjects was reported many years ago, but emerging evidence has suggested that the relationship may not be as strong as once thought. We have now determined a range of acidogenicity variables in subjects having both caries prevalence and incidence data, and have included plaque mineral data in the analysis. pH measurements were made in 20 randomly selected subjects from a high-caries group (mean DMFS = 8. 95) and 20 from a caries-free group of Beijing children aged 12 years participating in a caries prediction study. Subgroups with a 12-month DMFS increment >/=2 or = 0 were also formed from the two groups, respectively. Measurements were made with an iridium oxide electrode inserted between teeth 13/14, 23/24, 34/35 and 44/45, before and every 5 min for 30 min after rinsing with 10% sucrose, and the 4 resulting 'Stephan curves' averaged using a plaque pH analysis program. Supragingival plaque was collected from buccal and lingual smooth surfaces of posterior and upper anterior teeth and its acid extract analysed for Ca, P and F. Caries-free subjects (based on past experience) had a significantly higher maximum plaque pH and pH value after 30 min (reflecting a faster return to resting pH), a lower minimum enamel dissolution capacity of plaque and recorded less time below pH 7.0 than did high-caries subjects. No other differences were significant, including those of the principal acidogenic parameters 'minimum pH attained after a sugar rinse', 'curve area below the critical pH of 5.5' and 'time below the critical pH'. Selection of the caries groups on the basis of both experience and incidence did not reveal significant differences in more parameters. Upper arch plaque was significantly more acidogenic than lower arch plaque, and there was a consistently strong association between upper and lower arch values in individuals. Ca, P and F in the subjects' plaque had little or no influence on the principal acidogenic parameters. Our failure to find a relationship between caries prevalence or activity and these principal acidogenicity parameters may be related to differences between fissure and smooth surface plaque, temporal variations in acidogenicity and/or to use of F toothpaste during the 1-year observation period. These results support the view that factors such as the frequency of acidogenic episodes may be more important in caries progression than the degree of acidogenicity during any one episode.

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.

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.

Monte Carlo estimation of extrapolation of quality-adjusted survival for follow-up studies

The expected quality-adjusted survival (QAS) for an index population with a specific disease can be estimated by summing the product of the survival function and the mean quality of life function of the population. In many follow-up studies with heavy censoring, the expected QAS may not be well estimated due to the lack of data beyond the close of follow-up. In this paper, we first created a reference population from the life tables of the general population according to the Monte Carlo method. Secondly, we fitted a simple linear regression line to the logit of the ratio of quality-adjusted survival functions for the index and reference populations up to the end of follow-up. Finally, combining information on the reference population with the fitted line, we predicted the expected quality-adjusted survival curve beyond the follow-up period for the index population. Simulation studies have shown that the simple Monte Carlo estimation procedure is a potential approach for estimating expected QAS and the survival function beyond the follow-up with a certain degree of accuracy.

Long-term effect of increased lead absorption on intelligence of children

The authors examined the reversibility of cognitive impairment caused by a mild increase in lead absorption among children. The results of our initial study revealed that air and soil outside a lead-recycling plant in Taiwan were seriously contaminated by lead, which was associated with lowered intelligence quotients of 32 children who attended a nearby kindergarten (i.e., kindergarten A). Thirty-five children-who were comparable with respect to age, sex, birth order, sibling number, and parental education level-from another kindergarten (i.e., kindergarten B) located 5 km from the plant were enrolled as the reference group. Following the initial study, kindergarten A school children moved 2 km from the lead-recycling plant. Twenty-eight children in each group were followed successfully 2.5 y later. Blood lead, intelligence quotient, and intelligence quotient-related factors were reassessed. The results showed that the average blood lead level of the exposed pupils dropped 6.9 microg/dl (standard deviation [SD] = 3.9 microg/dl) (p < .001), and the average intelligence quotient increased 11.7 points (SD = 13.2) (p < .01), compared with the results of the initial study. The average blood lead level of the reference group decreased by 1.7 microg/dl (SD = .1.3) (p < .001), whereas the average intelligence quotient increased by 4.2 points (SD = 13.8) (p = .115). There was a significant difference in intelligence quotients between the two groups during the initial study, but the difference subsequently disappeared during the follow up. The authors concluded that intelligence quotient impairment, caused by a mild subclinical elevation of blood lead (i.e., likely no more than 30 microg/dl) for a period of 1-3 y in 3- to 5-y-olds, is at least partially reversible.

Early induction of apoptosis in androgen-independent prostate cancer cell line by FTY720 requires caspase-3 activation

BACKGROUND

We previously reported that FTY720, a metabolite from Isaria sinclairii, induced some cancer cells to undergo apoptosis, and that FTY720-induced apoptosis was not related to Fas-antigens. In this study we investigated whether FTY720 was able to induce apoptosis in an androgen-independent prostate cancer cell line, DU145, which is not only resistant to androgen-withdrawal-induced apoptosis but also Fas- and TNF-alpha-mediated apoptosis.

METHODS

Cell survival and morphological change were examined and apoptosis was confirmed by DNA isolation and analysis of DNA fragmentation. Caspase activation was studied by using anti-caspase-1 and anti-caspase-3 antibodies. To determine whether caspase activation is central to FTY720-induced apoptosis, caspase inhibitor was added to the media 24 hr prior to the addition of FTY720.

RESULTS

We found that FTY720 rapidly induced apoptosis in DU145 cells, and that caspase-3 was activated during FTY720-induced apoptosis. In contrast, normal human prostate stromal cells were resistant to FTY720. Furthermore, FTY720-induced apoptosis was prevented by caspase-3 inhibitor.

CONCLUSIONS

The data in this report show that FTY720 is a potential strong antitumor agent for cell line DU145, and provide the first evidence for involvement of caspase-3 in apoptosis of an androgen-independent prostate cancer cell line. Activation of such caspases may provide a means for eliminating androgen-independent prostate cancer in humans.

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.

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.

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.

Risk assessment of lung cancer and mesothelioma in people living near asbestos-related factories in Taiwan

Estimates from environmental risk assessments are criticized by professionals who indicate that inaccuracies occur in exposure assessment, model selection, and determination of the population at risk. In the current study, we tackled the aforementioned issues and estimated the risks of lung cancer and mesothelioma caused by airborne asbestos among individuals who lived near asbestos factories in Taiwan. We conducted 8-h full-period samplings upwind and downwind from each factory, and we used transmission-electronic microscopy (10,000x) and phase-contrast microscopy to determine asbestos concentrations in and around each factory. We estimated the numbers of residents who lived in concentric circles of 200-m, 400-m, and 600-m diameters around each factory. A dose-response model for asbestos-induced lung cancer was adopted from a summary of seven epidemiological studies. The asbestos-mesothelioma models were patterned after the first-exposure-effect models developed by Peto and Finkelstein. The data obtained from phase-contrast microscopy significantly overestimated the risk, compared with transmission-electronic microscopy. The estimates we calculated from adopting the arithmetic mean were approximately 2-fold higher than those we calculated with the geometric mean. There were relatively low concentrations of asbestos in the study areas, thus causing an absence of a significant difference in risk estimates between different models for mesothelioma. Among the more than 20,000 residents who lived near 41 asbestos factories in Taiwan, we found that the numbers of expected excess deaths from lung cancer and mesothelioma were 5 and less than 1, respectively. We concluded that in future risk assessments for ambient asbestos exposure, investigators should adopt transmission-electronic microscopy and the geometric mean estimate. Moreover, Taiwan should enhance asbestos-control programs to assure the safety of residents who live near asbestos factories.

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.

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.

Determinants of lethality from suicidal pesticide poisoning in metropolitan HsinChu

Acute pesticide poisoning is a global health problem, especially in developing countries. Although Taiwan has quickly industrialized during the last several decades, pesticide use is still prevalent in the agricultural sector. We reviewed 187 consecutive hospitalized cases of the Provincial HsinChu Hospital from January 1989 through December 1995 to explore the determinants of acute pesticide poisoning in Metropolitan HsinChu. The annual incidence rate of acute pesticide poisoning was 3.2/100,000 with an overall fatality rate of 23% which was more severe than the rates found in developed countries. The major agents involved were organophosphates, and the major cause of poisoning was suicide. Alcohol abuse, history of major medical illnesses, and history of suicide were significantly associated with suicidal poisoning; quarrel was the immediate risk factor. Causes of poisoning (suicide vs non-suicide) and selection of the pesticides were major determinants of lethality. More stringent legislation and enforcement regarding the sale and distribution of extremely toxic pesticides are needed to reduce fatalities due to acute pesticide poisoning.

Plasma Asp13-Ki-ras oncoprotein expression in vinyl chloride monomer workers in Taiwan

Vinyl chloride (VC) workers are known to be at risk for development of liver angiosarcoma, a rare tumor. Previously, more than 80% of VC workers with liver angiosarcoma have been found to have an Asp-13 c-Ki-ras oncogene mutation, and more than 50% of VC-exposed workers without liver tumors were found to have Asp13-Ki-ras oncoprotein in their plasma. Some workers in Taiwan had also been exposed to VC, and some have contracted liver tumors. In this study, we used enhanced chemiluminescence Western blotting to detect Asp13-p21-Ki-ras in the sera of VC-exposed workers in Taiwan. There were 14 of 113 (12.4%) VC workers positive for the Asp13-Ki-ras oncoprotein in plasma, but 0 of 18 controls were positive. There were 10 of 69 (14.5%) plasma-positives among the more highly exposed (> 1000 ppm-months) workers and 4 of 48 (9.1%) plasma-positives among the lesser exposed (< or = 1000 ppm-months). Compared with the unexposed controls, the odds ratios (and 95% confidence intervals [CI]) for plasma-positivity were 4.11 (95% CI = 0.21, 80.4) in the lower-exposed workers and 6.53 (95% CI = 0.37, 116.9) in the higher-exposed workers, and there was a linear trend between exposure and plasma-positivity (P = 0.073). After adjusting for age and drinking status, the odds ratios (and 95% CIs) were 1.64 (95% CI = 0.17, 15.8), and 2.65 (95% CI = 0.42, 16.8), respectively, and there was a significant linear trend between exposure and plasma-positivity (P = 0.048). In summary, Asp13-Ki-ras oncoprotein can be found in the plasma of VC workers in Taiwan, and a significant dose-response relationship exists between plasma oncoprotein expression and VC exposure.

Seasonal variation of chickenpox, mumps and rubella in Taiwanese children estimated by pediatric clinics

To determine the seasonal variation of childhood infectious diseases in Taiwan, the incidence rates of chickenpox, mumps and rubella were studied by analyzing patient's records collected from pediatric clinics in northern, central, southern and eastern Taiwan from January 1, 1993 to December 31, 1993. The study revealed that a chickenpox outbreak was most likely to occur in autumn, followed by a second peak in spring, and the lowest rate in summer. In this study, the highest monthly incidence of chickenpox was 540 cases per 100,000 population. The highest incidence of mumps occurred in the spring, the second highest in autumn, and the lowest during summer. Cases of rubella occurred in the spring, summer and autumn, but not in the winter. The data on chickenpox from this study revealed a similar seasonal pattern every year to that of the Department of Health of the National Quarantine Service on Taiwan. The chickenpox virus is known to be relatively sensitive to elevations in ambient temperature and is characterized by its occurrence mainly in slightly humid seasons.

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.

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.

Increased morbidity odds ratio of primary liver cancer and cirrhosis of the liver among vinyl chloride monomer workers

OBJECTIVES

To determine if there is an increased risk of admission to hospital for various diseases among vinyl chloride monomer (VCM) workers.

METHODS

2224 workers with occupational exposure to VCM were identified for occurrence of disease based on a search of hospital computer files on labour insurance. These data were compared with those of workers manufacturing optical equipment and motorcycles from 1 January 1985 to 31 March 1994. Cardiovascular and cerebrovascular diseases were used as reference diseases, and the age adjusted morbidity odds ratio (MOR) was calculated.

RESULTS

A significantly increased risk of admission to hospital among VCM workers due to primary liver cancer (MOR 4.5-6.5), cirrhosis of the liver (MOR 1.7-2.1), and other chronic diseases (MOR 1.5-2.0) was found. There were eight cases of primary liver cancer, all with heavy previous exposure to VCM. Another four cases of hepatoma in polyvinyl chloride (PVC) workers were found in the death registry. Ten out of 11 cases of hepatoma, with detailed medical information, were carriers of hepatitis B virus. The average latent period (20 years) was not different from other studies. Alternative agents of primary liver cancer were largely ruled out, suggesting that the combination of hepatitis B and VCM may lead to primary liver cancer.

CONCLUSION

There is an increased risk of primary liver cancer in workers exposed to VCM, although the incomplete coverage of the Labor Insurance Bureau data warrants cautious interpretation of the results. Further study exploring the synergistic effects of VCM and hepatitis B is also indicated.

Chinese herbal medicine, sibship, and blood lead in children

OBJECTIVES

Risk factors for increased blood lead concentration (BPb) has been investigated. However, the effect of sibship and Chinese herbal medicine on BPb has not been systematically studied. In this study BPb data from voluntary testing was used to determine if Chinese herbal medicine and sibship were associated with BPb.

METHODS

319 children aged 1-7 were tested for BPb. Meanwhile, parents were interviewed to obtain information including consumption of Chinese herbal medicine, living environment, lifestyle, and sibship of the children tested.

RESULTS

The mean (SD) BPb of 319 preschool children was 4.4 (2.4) micrograms/dl. The consumption of Ba-baw-san (a Chinese herbal medicine) was significantly associated with increased BPb in children (p = 0.038). Further multivariate regression analysis of BPb in 50 pairs of siblings showed the factors of being brothers explained 75% of variation for BPb, and being sisters and brother-sister explained 51% and 41% of variation respectively.

CONCLUSION

Chinese herbal medicine and children's play patterns within the family expressed in different types of sibship are the main determinants of low concentrations of BPb in preschool children of Taiwan.

Pregnane glycosides, gymnepregosides A-F from the roots of Gymnema alternifolium

The structural elucidation of six new related polyoxypregnane glycosides, gymnepregosides A (1), B (2), C (3), D (4), E (5) and F (6), together with two known compounds, from the roots of Gymnema alternifolium (Asclepiadaceae) was achieved through on a detailed study of 1H- and 13C-NMR spectral data and chemical means. The results obtained for new compounds, 1-6, show that they are (20S)-pregn-6-ene-3 beta,5 alpha,8 beta,12 beta,14 beta,17 beta,20-heptaol or sarcostin 3-O-glycosides, and all the sugars at C-3 are beta(1-->4)-linked. Some of them possessed benzoyl, cinnamoyl and tigloyl residues as the ester linkages located at C-12 and/or C-20 of the aglycon.

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.

Occupational and environmental lead poisoning: case study of a battery recycling smelter in Taiwan

The rapid industrialization in Taiwan has caused both prosperity and environmental pollution. The purpose of this study is to demonstrate a case of both occupational and environmental lead poisoning. A patient of lead poisoning initiated a survey of the battery recycling factory, which revealed that 31 of 64 workers suffered from lead poisoning. Children who attended a nearby kindergarten showed a significant increase of blood lead up to 15-25 micrograms/dl and a mild but significant decrease of IQ (intelligent quotient, by Binet-Simon scale) if compared with children of a nonexposed but socioeconomically comparable kindergarten. Outdoor workers of the nearby forging factory also showed a significant increase of blood lead if compared with indoor workers or workers of another nonexposed forging factory 20 Km away. Air sampling showed an average of more than 10 micrograms/m3 in the kindergarten. Soil sampling and analysis also revealed 400 folds increase of lead content, which decreased if the sample was taken deep down to 15-30 cm or 350 meters away from the battery recycling smelter. Moreover, after children were moved away from the pollution source, follow-up examination performed 2.5 years later showed a significant decrease of blood lead and partial recovery of IQ among them.

Adverse effect of air pollution on respiratory health of primary school children in Taiwan

This study is a part of the Study On Air Pollution and Health In Taiwan (SOAP&HIT), an ongoing research project involving cooperation of several universities in Taiwan. In this study, the objective was to evaluate the effects of ambient air pollution on respiratory symptoms and diseases of school children, in addition to considering indoor air pollution. Six communities were selected: one community located in a rural area (Taihsi), two in urban areas (Keelung and Sanchung), and the other three in petrochemical industrial areas (Toufen, Jenwu, and Linyuan). We sampled 5,072 primary school students in six communities from the main study population of SOAP&HIT. Respiratory health was assessed by evaluation of the children's respiratory symptoms and diseases using a parent-completed questionnaire. Data were analyzed using logistic regression analysis to compute odds ratios of adverse effect. The school children in the urban communities had significantly more respiratory symptoms (day or night cough, chronic cough, shortness of breath, and nasal symptoms) and diseases (sinusitis, wheezing or asthma, allergic rhinitis, and bronchitis) when compared with those living in the rural community. However, only nasal symptoms of children living in the petrochemical communities were more prevalent than in those living in the rural community. Although the association with ambient air pollution is suggestive, the cross-sectional study cannot confirm a causal relationship; thus further studies are needed.

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.

Radiation exposure modeling for apartment living spaces with multiple radioactive sources

Since late 1992, over 100 building complexes in Taiwan, including both public and private schools, and 1,000 apartments have been identified as emitting elevated levels of gamma-radiation. These high levels of gamma-radiation have been traced to construction steel contaminated with 60Co. Accurate reconstruction of the radiation exposure dosage among residents is complicated by the discovery of multiple radioactive sources within the living spaces and by the lack of comprehensive information about resident life-style and occupancy patterns within these contaminated spaces. The objective of this study was to evaluate the sensitivity of current dose reconstruction approach employed in an epidemiological study for the health effects of these occupants. We apply a statistical method of local smoothing in dose rate estimation and examine factors that are closely associated with radiation exposure from multiple radioactive sources in the apartment. Two examples are used, a simulated measurement in a hypothetical room with three radioactive sources and a real apartment in Ming-Shan Villa, one of the contaminated buildings. The simulated and estimated means are compared along 5-10 selected points of measurement: by local smoothing approach, with the furniture-adjusted space, and with the occupancy time-weighted mean. We found that the local smoothing approach came much closer to theoretical values. The local smoothing approach may serve as a refined method of radiation dose distribution modeling in exposure estimation. Before environmental exposure assessment, "highly occupied zones" (HOZs) in the contaminated spaces must be identified. Estimates of the time spent in these HOZs are essential to obtain accurate dosage values. These results will facilitate a more accurate dose reconstruction in the assessment of residential exposure in apartments with elevated levels of radioactivity.