摘要:

The mutagenicity of a benzene/methanol extract of fly ash from an atmospheric fluidized‐bed combustor burning Beulah, N.D., lignite was tested in Salmonella. Six strains were used, including three that were mutants in a nitroreductase gene locus. The numbers of revertants from his−to his+as a function of the amount of fly ash extracted were determined. The results showed that the major mutagens in the crude extract were nitro compounds, from the fact that reversion rates in the nitroreductase‐deficient strains were significantly lower than in the parent strains from which they were derived. The responses of the three parental strains, TA 1538, TA98, and TA 100, were quite similar; thus no conclusions could be made about frameshift versus base‐substitution mutagens. Mutagenicity of 15 fractions of the extract was also tested, and one major peak of activity was detected. This activity eluted from a high‐performance liquid chromatograph outside the range of retention times associated with mononitro‐aromatics. No further identification of specific nitroorganic compounds has been made.

ISSN:0098-4108    

DOI:10.1080/15287398409530599

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Mutagenicity of tobacco snuff extracts was studied using the AmesSalmonella/microsome assay system. No mutagenic activity was found for tobacco snuff extracts without S9 activation. However, mutagenic substances were formed from tobacco snuff extracts in an acidic environment. The mutagenic substances induced predominantly frameshift mutations and were direct‐acting mutagens. Mutagenic activity of tobacco snuff extracts was enhanced in the presence of coal‐dust extracts at low pH. Since tobacco snuff has been used by some coal miners to substitute for cigarettes, a possible risk for gastric cancer induction among coal miners is proposed.

ISSN:0098-4108    

DOI:10.1080/15287398409530600

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Rabbit alveolar macrophages were exposed in culture to chrysotile asbestos, wollastonite, or latex, and the effects on various biochemical and physiological parameters related to cellular viability and fibrogenicity were determined. Exposure of alveolar macrophages to asbestos, wollastonite, or latex for 3 d has no effect on oxygen consumption or cellular volume. However, treatment of alveolar macrophages with as little as 25 μg asbestos/ml for 1 d increases Iysosomal enzyme release and decreases membrane integrity, i.e., decreases trypan blue exclusion and increases leakage of cytosolic enzymes. In contrast, exposure of alveolar macrophages to wollastonite or latex at 250 μg/ml does not induce Iysosomai enzyme release or alter membrane integrity even after 3 d of exposure in culture. These data suggest that chrysotile asbestos damages rabbit alveolar macrophages, while wollastonite, a potential substitute for asbestos, is far less cytotoxic.

ISSN:0098-4108    

DOI:10.1080/15287398409530601

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The inhalation, by grain elevator workers, of airborne grain dusts can lead to pulmonary problems. Complement, which is present in human airways, can interact with various grain dusts, producing activation products that have been shown to participate in the inflammatory reaction. Because of this apparent connection between grain‐dust inhalation, complement activation, and respiratory difficulties, we are studying the reaction of an aqueous extract of spring wheat dust (swd) with human complement. The swd extract activates both the classical and alternative pathways; it acts on purified C2 to inhibit it, and it reacts with undiluted serum to consume C4 with kinetics significantly different from those shown by a “typical” antigen‐antibody complex (sensitized sheep erythrocytes). Enzyme susceptibility experiments suggest that the alternative and classical pathway activators of swd extract are neither protein nor nucleic acid; periodate oxidation indicates these substances are carbohydrate, and gel filtration suggests they are macromolecular. Enzyme vulnerability also indicates that the C2 inhibitor of swd extract is ribonucleic acid. Although endotoxin is present in swd extract, a gel‐filtration experiment showed that a major fraction of the complement reactivity was not associated with this substance.

ISSN:0098-4108    

DOI:10.1080/15287398409530602

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Laboratory shelling and pilot handling operations were conducted to determine If peanut dust generated by such operations contained significant amounts of aflatoxin. Air samples were collected from points of highest dust concentration. No aflatoxin B1was detected in dust from uncontaminated lots. Aflatoxin B1levels of 700 ppb and 7.6 ng/m3were detected from highly contaminated lots. The contamination of the dust was directly proportional to the contamination of the lots handled or shelled. In the shelling tests, the level of contamination of the dust samples was about one‐ninth of the level of contamination of the peanuts. In the handling tests, the level of contamination of the dust samples was about half the contamination level of the peanuts. These results indicate that most of the contaminated dust was probably removed by handling operations prior to shelling. Although workers are not routinely exposed to such levels of contaminated dust, these findings suggest the need for a more thorough study of peanut dust during handling or processing of contaminated peanuts.

ISSN:0098-4108    

DOI:10.1080/15287398409530603

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The effects of ochratoxin A (OA), a nephrotoxic mycotoxin, were investigated in partially nephrectomized (PN) rats (approximately 70% reduction in renal mass) following compensatory hypertrophy of the renal remnant. Renal function stabilized 27 d after surgery. PN rats compensated for the initial loss of renal function except for glomerular filtration rate (GFR, inulin clearance); this remained significantly impaired. Sham‐operated (SO) rats cleared inulin and p‐aminohippurate (PAH) at rates of 3.84 and 7.49 ml/min, respectively, while compensated PN rats cleared inulin at 2.51 and PAH at 8.84 ml/min. Daily administration of low levels of OA produced decreased urine osmolality and body weight with a modest increase in urinary protein of PN versus SO rats. OA‐treated rats cleared inulin, creatinine, and PAH at rates significantly lower than nontreated controls: 0.89 and 1.96 ml/min for inulin, 0.35 and 0.56 ml/min for creatinine, and 2.29 and 6.23 ml/min for PAH. Histopathological findings indicated a considerable increase in renal tubular necrosis and subcellular damage (i.e., loss of cytoplasmic ground substance, vacuolization, degeneration of mitochondria, and reorganization of endoplasmic reticulum) in PN animals versus controls, concurrent with alteration in renal function. These results verify that the nephrotoxic action of OA is elicited mainly in renal proximal tubules and is enhanced in the PN rat.

ISSN:0098-4108    

DOI:10.1080/15287398409530604

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Over 3000 female C3H/Hen‐MTV+ mice continuously received graded dietary levels (0, 2.5, 5, JO, 20, 40, 80, 160, 320, and 640 ppb) of diethylstilbestrol (DES) beginning at weaning. Mice were scheduled to be killed after 3 or 26 wk of exposure and were palpated weekly and removed for histological evaluation when subcutaneous masses reached 1 cm diameter. Mammary tumors were more prevalent than in controls only at 320 and 640 ppb DES. However, palpable mammary tumors appeared significantly earlier than in controls in mice fed 80 ppb and above. Mice killed at 3 wk and later showed a dose‐response for several nonneoplastic endpoints. At 3 wk, moderate to severe uterine glandular hyperplasia, lack of corpora lutea, and vaginal keratinization were more prevalent than in controls at 80 ppb; cervical adenosis was more prevalent than in controls at 160 ppb and above. Generally, the prevalence of other nonneoplastic responses such as uterine fibrosis, stromal mucoid changes, and bony trabecular proliferation were increased above control levels only later than 3 wk at 160 ppb and greater. This study demonstrated neoplastic and nonneoplastic responses to DES at and above 80 ppb, but gave no clear evidence of either type of response below this level. Conclusions are, (1) dietary levels of DES causing nonneoplastic effects also cause neoplastic effects when fed chronically, and (2) neoplastic levels of DES may be predicted from a 3 wk feeding study in C3H/HeN‐MTV+ female mice based on nonneoplastic responses.

ISSN:0098-4108    

DOI:10.1080/15287398409530605

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Pregnant mice were exposed to 150 μg benzo[a]pyrene (BaP) per gram of body weight duirng fetogenesis (d 11–17 of gestation) and the progeny were assayed for humoral and cell mediated immune responses at different time intervals after birth. Immature offspring (1–4 wk) were severely suppressed in their ability to produce antibody‐(plaque‐) forming cells (PFC) against sheep red blood cells (SRBC) and in the ability of their lymphocytes to undergo a mixed lymphocyte response (MLR). Lymphocytes from these progeny showed a moderate to weak capacity to inhabit production of colony‐forming units (CFU) in host spleens following transfer with semiallogeneic bone marrow (BM) cells into lethally X‐irradiated recipients syngeneic to the BM (in vivograft‐versus‐host response, GVHR). A severe and sustained suppression in the MLR and the PFC response occurred from the fifth month up to 18 mo. Thein vivoGVHR, also subnormal later in life, was not as severely suppressed as the other two parameters. Tumor incidence in the BP‐exposed progeny was 8‐ to 10‐fold higher than in those encountering corn oil alone from 18 to 24 mo of age. These data show thatin uteroexposure to the chemical carcinogen BaP alters development of components needed for establishing competent humoral and cell‐mediated functions of the immune apparatus and leads to severe and sustained postnatal suppression of the defense mechanism. The immunodeficiency exhibited, particularly in the T‐cell compartment (MLR, GVHR), before and during the increase in tumor frequency, may provide a favorable environment for the growth of nascent neoplasms induced by BaP.

ISSN:0098-4108    

DOI:10.1080/15287398409530606

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

To assess the potential effect of cyclopiazonic acid (CPA) on pregnancy and fetal development, Fischer‐344 rats were dosed daily with 0, 1, 5, or 10 mg CPA/kg body weight on either d 8–11 or d 12–15 of pregnancy (sperm day = d 1). There were significant (p < 0.05) decreases in feed consumption by high‐dose dams of both groups. One high‐dose rat in each group died prior to term, and signs of toxicity were observed in other high‐dose animals. Animals that died had histologic lesions in the liver, spleen, kidney, and other organs. Remaining dams were killed on d 21. Compared to controls, there were no significant differences in pup weights, percentage pre‐ or postimplantation losses, or fetal deaths. Significant differences in skeletal development included retardation of ossification of cervical centra (d 12–15) and caudal vertebrae (d 8–11) in the two highest dose groups. Retardations of development were the most common manifestations of embryotoxicity. Since significant maternal toxicity occurred at the highest dose level in the absence of fetal malformations, the teratogenic potential of CPA is low.

ISSN:0098-4108    

DOI:10.1080/15287398409530607

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The disposition of [14C]‐labeled 2‐mercaptobenzimidazole (MBI) in male Fischer‐344 rats dosed orally (49 or 0.5 mg/kg) or intravenously (0.5 mg/kg) was determined. Absorption of the oral dose was evident, since, in 72 h, most of the radioactivity administered by either route appeared in the urine. Smaller amounts appeared in the feces. In 4 h, 12% of the radioactivity from an intravenous dose of 0.5 mg/kg was excreted in the bile of rats with biliary cannulas.

ISSN:0098-4108    

DOI:10.1080/15287398409530608

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor