摘要:

It has been suggested that benzene metabolites might be good indicators of smoking. Moreover, benzene could stimulate the neutrophil lineage while depressing the lymphocytic and erythroid lineages, possibly by an interference with cytokines. The effect on the neutrophil lineage could explain the smokers' leukocytosis, the mechanism of which is presently unknown. Therefore, the usefulness of benzene metabolites as indicators of smoking was compared to that of cotinine and thiocyanate, and the relationships between benzene metabolites, the hematological parameters of smokers, and interleukin 1a production were examined. The results show that benzene metabolites are not better indicators of smoking status than cotinine or thiocyanate. Furthermore, it seems unlikely that the smokers' leukocytosis is benzene induced.

ISSN:0098-4108    

DOI:10.1080/00984109708984049

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Mercury (Hg) concentrations in individual spot urine samples collected over consecutive I'd periods were compared with Hg concentrations measured in combined 24-h urine samples from 69 practicing dental professionals with low exposure to Hg vapor (Hg°) in order to validate the use of spot urine samples as an indicator of Hg exposure. The level of Hg° in air as an exposure measure was also evaluated by comparing air concentrations of Hg° in dental offices with both spot and 24-h urine Hg° levels. The results showed: (1) There was little diurnal variation (∼9%) in urinary Hg values; (2) a strong correlation (R2=.85) exists between the Hg concentration in the first morning void and that in a complete 24-h urine sample; (3) adjustment of urinary Hg levels for creatinine concentrations did not improve this correlation; (4) there was no added value in the speciation of total urinary Hg into the inorganic Hg fraction; and (5) concentrations of Hg° in air did not significantly correlate with measures of Hg in urine at this low Hg° exposure level. We conclude from this study that first morning void urine samples may be used to derive reasonably valid

ISSN:0098-4108    

DOI:10.1080/00984109708984050

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

By using the in vitro Ames Salmonella/microsomal assay and the in vivo mouse micronu-cleus assay, studies were performed to evaluate the genotoxicity of gasoline exhaust particulate matter generated from five different domestic and imported scooters. In the Ames assay, treatment of test strains TA98 and TA100 with solvent extracts of particulate matter from four of five scooter models caused an increase in the number of histidine-indepen-dent colonies over the background in TA98 without S9 mix. Positive results were also obtained from the micronucleus assay. The frequencies of bone marrow micronucleated polychromatic erythrocytes were significantly higher in the treated compared to the non-treated animals, and the increases in the frequencies were not significantly different among the five types of scooters. Analyses of chemical components showed that scooter exhaust particulate matter contained more than 100 different substances including polycyclic aro-U matic hydrocarbons.

ISSN:0098-4108    

DOI:10.1080/00984109708984051

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Benzo[a]pyrene (BaP) is known to induce tumors in lung, forestomach, and skin in experimental animals. Earlier studies have suggested that glutathione S-transferase n (GST pi) is involved in the detoxification of the “ultimate” carcinogenic metabolite of BaP, 7p, 8a-dihydroxy-9a, IO(x-oxy-7tBt9tIO-tetrahydrobenzo[a]pyrene (BPDE). The constitutive expression of GST pi in the liver of the male CD-1 mouse is higher than that of the female, and BHA has been shown to preferentially induce GST pi in the female as compared with the male mouse. The present studies were therefore designed to compare the susceptibility of male and female CD-I mice to the carcinogenic effects of BaP and the protective effect of BHA. Results of these studies show that the female CD-1 mice are more susceptibile to the carcinogenic effect of BaP than the males and that the attenuation of BaP-induced carcinogenesis by BHA appears to be restricted only to the females.

ISSN:0098-4108    

DOI:10.1080/00984109708984052

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Although exposure to styrene occurs primarily via inhalation, the action of this agent on the respiratory tract has scarcely been investigated. This article describes morphological and biochemical changes occurring in the respiratory tract of rats after either inhalation of styrene vapors (300 ppm, 6 hid, 5 d/wk, for 2 wk) or systemic (ip) treatment with 40 or 400 mg/kg styrene for 3 consecutive days. Electron microscopy analysis showed diffuse cell damage involving the tracheal, bronchiolar, and alveolar epithelium. In the tracheal epithelium, several cell types were affected. Ciliated cells presented vacuolation, detachment of cilia, blebbing of the apical cytoplasm, and compound cilia. Most secretory cells showed scant secretory granules and blebbings. Dense bodies and fibrillary inclusions were seen in intermediate and basal cells. Styrene also caused alterations of cytoplasmic components in type II pneumocytes and bronchiolar cells as well as thickness of the alveolar wall. These abnormalities were accompanied by depletion of glutathione (GSH) in the lung tissue. Pneumotoxic effects of systemic administration of styrene were dose dependent and tended to be more severe than those seen in the animals exposed for longer periods to styrene by inhalation. Metabolic activation of styrene and subsequent cell damage induced by the reactive metabolite styrene oxide may be involved in the sequence of events culminating in the toxic insult to the respiratory tract

ISSN:0098-4108    

DOI:10.1080/00984109708984053

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Two crude oils, differing in viscosity (V) and nitrogen (N) and sulfur (S) content, were evaluated for pre- and postnatal developmental toxicity. In Crude I (low V, low N, low S) studies, the material was applied neat to the clipped backs of pregnant rats at dose levels ofO, 125, 500, WOO (postnatal only), and 2000 (prenatal only) mg/kg. In Crude II (high V, high N, moderate S) studies, the oil was applied similarly but at dose levels of 0, 30, 125, and 500 mg/kg. Rats were exposed to the crude oils on gestation days (CD) 0-19; application sites were not covered. “Prenatal” rats were killed on CD 20. “Postnatal” rats were allowed to deliver naturally; surviving dams and litters were killed 3-4 wk postpar- turn. Both crude oils produced maternal and developmental toxicity. Adverse fetal effects included increased in utero death, decreased body weight, and reduced ossification of skeletal elements. Parturition was delayed in Crude II dams at 500 mg/kg. The 4-d viability index was decreased in all Crude ll-exposed groups. Pup body weights were decreased by each oil, but at the high dose only. Prenatal effects are probably related to polynuclear aromatic compounds (PAC) found in petroleum. The cause(s) of delayed parturition and postnatal toxicity have not been determined.

ISSN:0098-4108    

DOI:10.1080/00984109708984054

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor