ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

For the estimation of cancer risks from environmental chemicals, knowledge of the target dose is essential, dose being defined as the time integral of concentration in target tissues. In vivo doses from chronic or intermittent exposures are best determined from established steady-state levels of macromolecule adducts of reactive compounds or intermediates. For dose monitoring, hemoglobin (Hb) is preferred to DNA for several reasons: accessibility in large amounts, availability of methods for chemical identification, and well-determined life span due to absence of repair. For these reasons, and because of the proportionality of rates of DNA and Hb adduct formation, Hb adduct levels give better information on cumulative DNA adduct levels than do direct measurement of DNA adducts. The scientific background of Hb adduct measurement, target dose determination, and risk estimation based on the relative genotoxic potency, with y-radiation as reference standard, is reviewed and exemplified. The sensitivity of the method for Hb adduct measurement permits determination of exposures where the associated annual cancer risk is less than 1 per million. Besides application for studies of metabolism by determination of in vivo doses in exposed animals and humans, as a basis for risk estimation, Hb adduct measurement is used for hygienic surveillance of occupational exposures. Determination of Hb adducts by mass-spectrometric techniques gives a tool for identification of reactive metabolites, not only in individuals with known exposure, but also for characterization of adducts to Hb from compounds acting as mutagens (initiators) in the background carcinogenesis. This is the large fraction of the total number of cancer cases that occur among individuals without known exposure.

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Employees are often exposed to and bothered by environmental tobacco smoke (ETS) in the workplace; however, little is known about correlates of workers' perceptions of their exposure. In this study, 20,801 employees in 114 work sites in the United States were surveyed; variables related to perceptions of exposure and being bothered by ETS were entered into regression models. Many of the workplaces had, total or partial restrictions on smoking in the workplace; however, over half of the respondents (52.4%) reported they were exposed to ETS at work. Smoking policy, smoking status, age, gender, living with a smoker, and occupation contributed to models for perceived exposure and being bothered by tobacco smoke. Work site smoking restrictions seem to have an impact on employee attitudes concerning exposure to ETS. About 35% of employees were bothered regularly by smokiness at their workplaces, which made their working conditions both uncomfortable and exposed them to an unsafe working environment.

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Worker exposure to N,N-dimethylacetamide (DMAC) in an acrylic fiber manufacturing facility was measured, over a 1-year study period, by full-shift (12 hours) personal air monitoring for DMAC and by biological monitoring for levels of DMAC, N-methylacetamide (MMAC), and acetamide in spot urine samples. Ninety-three of 127 male workers in seven job classifications in the solution preparation and spinning departments of the plant were monitored on the second consecutive workday after at least 3 days off for the first 10 months of the study and on both the first and second days during the study's final 2 months. Postshift urinary MMAC levels were significantly correlated (P <. 0001, r2= .54) with DMAC in air levels. An air level of 6.7ppm 12-hour time-weighted average (TWA) corresponded to a urine MMAC level of 62 mg/g creatinine in a postshift spot urine sample obtained after the second consecutive workday. To minimize exposure misclassification due to variability in the regression relationship, a level of 35 mg MMAC/g creatinine in a postshift spot urine sample was recommended as a biomonitoring index. Postshift urine MMAC levels did not appear to plateau at higher air levels, nor did it appear that the DMAC demethylation metabolic mechanisms became saturated at threshold limit value (TLV)-level air-exposure levels. Urine MMAC levels in postshift samples obtained the second workday appeared to be greater than levels in postshift first-day samples, but the number of days until this postshift level would plateau could not be determined from this study. A level of 35 mg MMAC/g creatinine in a postshift urine sample obtained after as many consecutive workdays as feasible appears to be an acceptable biomonitoring index of exposure to DMAC for workers completing a 12-hour shift.

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Worker exposure to N,N-dimethylacetamide (DMAC) in an acrylic fiber manufacturing facility was measured, over a 1-year study period, by full-shift (12 hours) personal air monitoring for DMAC and biological monitoring for levels of DMAC, N-methylacetamide (MMAC) and acetamide in post-shift spot urine samples. Evidence of liver toxicity was assessed by serum clinical chemistry tests (serum levels of total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and y-glutamyl transpeptase) at least once during the study period for all 127 male workers in the two study departments and for 217 male in-plant controls with no previous or current exposure to DMAC. If a worker's biomonitoring results exceeded one of two “trigger” values established for the study (60 mg MMAC/g creatinine or 136 mg DMAC equivalent/g creatinine), additional serum clinical chemistry tests were conducted at weekly intervals for 3 weeks. DMAC-exposed workers were classified as either high exposure, if one or more biomonitoring result exceeded one of the trigger values, or unspecified exposure if none of them did. Control-group employees were classified as no-exposure. Mean DMAC in air levels for the high- and unspecifiedexposure groups appeared to differ (geometric mean DMAC in air levels of 1.9 and 1.3 ppm 12-hour time-weighted average, respectively). No significant DMAC exposurerelated trends in hepatic serum clinical chemistry results were detected. Neither transient increases in serum analyte levels after a “high” biomonitoring result (one that exceeded a trigger value) nor an elevated mean level over the study period when compared with in-plant controls were observed. These results suggest that brief threshold limit value—level exposures and chronic low-level exposure (maximum likelihood estimate of the arithmetic mean for DMAC in air for the high-exposure group over the study period was 3.0 ppm 12-hour time-weighted average) do not cause hepatotoxic clinical chemistry responses.

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

A cross-sectional study was performed to assess the utility of vibrotactile thresholds (VTs) obtained before and after a 10-minute period of wrist flexion as a method for detection of carpal tunnel syndrome (CTS) among adult subjects. Subjects with hand discomfort were recruited from patients referred to a university-based electromyography laboratory. Asymptomatic subjects were recruited from among office and technical staff at a professional school. In addition to electrophysiologic evaluation (EP), all subjects were offered VT measurement of the index and small fingers, bilaterally, before and after a 10-minute period of wrist flexion. A total of 144 subjects were recruited, and three hand-condition groups were established: 57 hands had symptoms andEP results compatible with CTS (Group 1), 58 hands had symptoms compatible with CTS and normal EP results (Group 2), and 123 hands had no symptoms and normal EP results (Group 3). Group 1 was considered the “diseasepositive” group, and Groups 2 and 3 were both considered “disease-negative” groups. Analyses were performed separately for dominant and nondominant hands, and results were pooled when appropriate.Outcomes of interest were the VTs obtained from the index and small fingers before and after 10 minutes of maximal voluntary wrist flexion as well as variables calculated from them. Significant differences in mean VT were observed between the three hand-condition groups for most of the outcomes evaluated. At any given level of specificity, the sensitivity of vibrometry performed after 10 minutes of wrist flexion was approximately two times that obtained before wrist flexion for detection of electrophysiologically confirmed CTS. At specificities of 70 and 80%, the best sensitivity observed among vibrometry outcomes obtained after wrist flexion were 61 and 57%, whereas the best sensitivities observed among vibrometry outcomes obtained before wrist flexion were 35 and 28%.

ISSN:1076-2752    

出版商:OVID    

年代:1995

数据来源: OVID