摘要:

The association between pulmonary obstruction (e.g., asthma) and occupational exposure to methyl cyanoacrylate (MCA) and ethyl cyanoacrylate (ECA) was examined in an occupational cohort of 450 persons at an adhesive production facility in Puerto Rico. Employee medical records containing information on physical examinations and pulmonary function tests (PFTs), as well as occupational histories, on each employee over a period of about 17 yr and industrial hygiene measurements were evaluated. The cohort analysis was based on a Cox proportional hazards model. Workers exposed to ECA or MCA were compared to workers unexposed to these chemicals with respect to their risk of becoming an ''incident case. An ''incident case was defined as any per son whose PFTs were normal at the time of employment, but later demonstrated an obstructive pattern, which was defined as a decline in the ratio of forced expiratory volume exhaled in 1 s to forced vital capacity (FEV /FVC) below 70%. A separate casecontrol analysis was also conducted that compared ''suspected cases, defined as all those whose PFTs ever demonstrated an obstructive pattern (e.g., asthma), to persons whose PFTs remained within normal limits throughout their employment with respect to their past peak and cumulative exposures to cyanoacrylates. All of these analyses showed no evidence that exposure to average short-term concentrations of ECA or MCA of less than 0.5 ppm and occasional daily peak exposures of at least 1.5 ppm (usually 10 min or less), with occasional higher concentrations during spills, were associated with an increased risk of pulmonary obstruction. However, the study suggested that persons occupationally exposed to cyanoacrylates were more likely to have some reversible eye or upper airway irritation than persons who were unexposed. 1

ISSN:1528-7394    

DOI:10.1080/009841000156943

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

The interaction of air particles and alveolar macrophages (AMs) may result in the release of proinflammatory cytokines. Normal mouse AMs were treated with concentrated air particle (CAPs) suspensions in vitro. After 5 h, cytokine release [macrophage inflammatory protein-2 (MIP-2) and tumor necrosis factor- a (TNF-a)] and phagocytosis of ambient air particles were measured. CAPs samples collected from urban air (Boston) on different days were used. The CAPs samples and their soluble and solid components caused significant MIP-2 and TNF- a production. Variability in the potency of samples collected on different days was observed. Trace endotoxin was measured in CAPs samples (EU/mg: 2.3 +/- 0.7, mean +/- SE, n = 10). A majority of biologic activity (cytokine induction) and endotoxin content was associated with the solid components. Neutralization of endotoxin by polymyxin B abrogated >80% of TNF- a induction by CAPs samples, but inhibited MIP-2 production by only 40%. The trace endotoxin present in CAPs caused much more MIP-2 production than predicted by concentration alone (28 +/- 8-fold increase, n = 9), indicating synergistic interaction with other AM-activating components of the particles. Data suggest that low levels of endotoxin may interact with air particles to activate lung macrophages.

ISSN:1528-7394    

DOI:10.1080/009841000156952

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Potential additive effects of ethanol consumption, a common life-style factor, and lowlevel benzene exposure, a ubiquitous environmental pollutant, were investigated. Ethanol is a potent inducer of the cytochrome P-450 2E1 (CYP2E1) enzyme, which bioactivates benzene to metabolites with known genotoxicity and immunotoxicity. A liquid diet containing 4.1% ethanol was used to induce hepatic CYP2E1 activity by 4-fold in female CD-1 mice. Groups of ethanol-treated or pair-fed control mice were exposed to benzene or filtered air in inhalation chambers for 7 h/d, 5 d/wk for 6 or 11 wk. The initial experiment focused on immunotoxicity endpoints based on literature reports that ethanol enhances high-dose benzene effects on spleen, thymus, and bone marrow cellularity and on peripheral red blood cell (RBC) and white blood cell (WBC) counts. No statistically significant alterations were found in spleen lymphocyte cellularity, subtype profile, or function (mitogen-induced proliferation, cytokine production, or natural killer cell lytic activity) after 6 wk of ethanol diet, 0.44 ppm benzene exposure, or both. This observed absence of immunomodulation by ethanol alone, a potential confounding factor, further validates our previously established murine model of sustained CYP2E1 induction by dietary ethanol. Subsequent experiments involved a 10-fold higher benzene level for a longer time of 11 wk and focused on genotoxic endpoints in known target tissues. Bone marrow and spleen cells were evaluated for DNA-protein cross-links, a sensitive transient index of genetic damage, and spleen lymphocytes were monitored for hprt -mutant frequency, a biomarker of cumulative genetic insult. No treatment-associated changes in either genotoxic endpoint were detected in animals exposed to 4.4 ppm benzene for 6 or 11 wk with or without coexposure to ethanol. Thus, our observations suggest an absence of genetic toxicity in CD-1 mice exposed to environmentally relevant levels of benzene with or without CYP2E1 induction.

ISSN:1528-7394    

DOI:10.1080/009841000156961

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Toxaphene is a complex mixture of chlorinated bornanes, bornenes, and bornadienes and was a heavily used insecticide in the United States until its use was restricted in 1982. There are conflicting reports regarding the potential for toxaphene to induce estrogenic responses in human and nonhuman animals. Due to the public concern over environmental estrogens, the estrogenicity of toxaphene was examined in a human breast-cancer cell assay, the MCF-7 focus assay, which is based on in vitro postconfluent cell proliferation and tissue restructuring. In this assay, 0.1-1 n M 17 b estradiol (E) produces maximum postconfluent proliferation and formation of multicel2 lular nodules or foci. Toxaphene was also tested for its ability (1) to bind the estrogen receptor (ER) in a competitive binding assay using recombinant human ER a (rhER) and in a whole-cell competitive ER binding assay, and (2) to alter the catabolism of E 2 in MCF-7 cell cultures. Results from the MCF-7 focus assay showed: (1) Toxaphene alone was not estrogenic between the concentrations of 0.5 n M and 10 mu M, (2) toxaphene in binary combinations with chlordane, dieldrin, or endosulfan (a or b) was not estrogenic, and (3) toxaphene was weakly antiestrogenic (it reduced the number of foci induced by 0.1 n M and 0.01 n M E2). Results from the competitive binding assays showed that (1) toxaphene alone did not bind rhER or ER in MCF-7 cells, and (2) toxaphene in binary combinations with other pesticides did not bind rhER. Results from the growth assay and radiometric analysis of E2catabolism showed that (1) toxaphene did not alter the growth rate of MCF-7 cell cultures over 13 d, and (2) toxaphene did not alter the catabolism of E2. In conclusion, results from the MCF-7 focus assay demonstrate that toxaphene is weakly antiestrogenic rather than estrogenic.

ISSN:1528-7394    

DOI:10.1080/009841000156970

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor