摘要:

The effects of ozone exposure on the metastasis of a fibrosarcoma (NR‐FS) that arose spontaneously in a C3H/He mouse was studied. Male C3H/He mice were exposed to 0.8, 0.4, 0.2, and 0.1 ppm ozone for 1, 3, 5, 7, and 14 d. After the exposure periods, the mice were infused intravenously with NR‐FS cells. At 2 wk postinfusion, the lungs were examined for colony development of metastasis. A significantly higher rate of pulmonary metastasis than that of normal mice was observed in the ozone‐exposed mice. The enhancement of metastasis due to ozone exposure varied with length of exposure and concentration of ozone.

ISSN:0098-4108    

DOI:10.1080/15287398709530967

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

To assess the early cellular inflammatory response of the lungs, 7 rats per group were exposed nose‐only to 13 mg/m3of chrysotile asbestos, 7 h/day for 2, 4, or 6 wk. Lung histopathology and bronchoalveolar lavage (BAL) were analyzed. In exposed animals, dose‐related bronchiolitis and fibrosis were found that were not seen in control rats (p < 0.001). In exposed rats, total BAL cells were increased six‐ to sevenfold over matched controls, and more cells were retrieved with longer exposure (p < 0.001). In the BAL, counts of macrophages, lymphocytes, and polymorphonuclear cells (PMNs) were each elevated in the exposed rats (each p < 0.001). PMNs seen histologically and in the BAL may be related to the time period examined. PMNs and lymphocytes observed throughout this 6‐wk study support the idea that these cells may have an important role in the early events of asbestos lung injury.

ISSN:0098-4108    

DOI:10.1080/15287398709530968

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Epididymal adipocytes, isolated from rats pretreated with [14C]‐2,4,5,2’,4’,5'‐hexa‐chlorobiphenyl (6‐CB), were utilized to examine the relationship between the mobilization of lipid and 6‐CB and to determine whether 6‐CB was differentially associated with subcellular organelles over time as has been demonstrated for newly synthesized lipid. Lipolysis, induced by the presence of 8 × 70−7M isoproterenol (ISO) for 50 min, depleted approximately 7% of total cellular triacylglycerols (TG) regardless of time from treatment with 6‐CB. The percentage of cellular 6‐CB released from adipocytes to incubation buffer infranatants was not correlated with the magnitude of lipolysis produced over the 50‐min incubation period; nor was the percentage of 6‐CB released to the buffers correlated with the length of the incubation period, regardless of the presence of ISO. Although adipocytes responded similarly to lipolytic stimuli independent of time (days) since 6‐CB treatment, significant decreases were found in the percentage of 6‐CB released from adipocytes over time. The in vitro labeling of this newly synthesized TG in fat cells with [U‐14C]glucose or [7‐14C]palmitate demonstrated that TG was differentially distributed among adipocyte organelles. Newly synthesized TG was also the first to be mobilized under lipolytic stimulus. 6‐CB was not released in a similar fashion, since radioactivity associated with the chemical levels of [14C]‐6‐CB and glucose‐derived14C in buffers were not correlated over time. 6‐CB was found to redistribute to all available lipid pools during the subcellular fractionation procedure and thus did not resemble TG. However, it is possible that 6‐CB may exist in equilibrium among organelle fractions and that it becomes sequestered within the nonsoluble lipid compartment with time, thus decreasing its appearance in the soluble buffer infranatants over the experimental time course.

ISSN:0098-4108    

DOI:10.1080/15287398709530969

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The ability of mineral‐oil‐based and synthetic cable insulating fluids to transform and promote transformation of mammalian cells in vitro have been studied. In experiments with the Syrian hamster embryo cell transformation assay, it was found that C15‐C18alkylbenzenes were the most potent inducers of transformation, followed by low‐viscosity and residual mineral oils. No activity and low cytotoxicity were found for a low‐viscosity polyisobutylene‐based oil. In the two‐stage transformation assay of C3H/10T1/2 cells, promoter activity was obtained with all fluids tested. A blend of residual and low‐viscosity mineral oils showed the highest activity. This oil possessed a low cytotoxicity and was tested at a relatively high concentration. The alkylbenzenes were more potent than the polyisobutylene‐based fluid. The alkylbenzenes were also found to possess initiating activity in the two‐stage assay, when 12‐O‐tetra‐decanoylphorbol 13‐acetate (TPA) was used as promoter. All the fluids showed low potency compared to benzo[a]pyrene and the tumor promoter TPA.

ISSN:0098-4108    

DOI:10.1080/15287398709530970

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The acute toxicity of extracts of blue‐green algae was tested in freshly prepared rat hepatocytes in suspension. The results were compared with the traditional in vivo mouse bioassay. Sixty samples of natural algal blooms from freshwater lakes in Norway, Sweden, and Finland and 14 samples cultured in the laboratory were tested. The mouse bioassay revealed hepatotoxins in a large number of the algae, while neurotoxins were not found. Acute hepatotoxicity in vitro was scored by measurement of leakage of the enzyme lactate dehydrogenase (LDH) from damaged cells and of morphological changes of the cells. The correlation coefficients between mouse toxicity and LDH, mouse toxicity and morphological cell damage, and between LDH and morphological cell damage were 0.812, 0.735, and 0.882, respectively. Consequently, the rat hepatocyte toxicity test seems to be well suited for screening blooms of blue‐green algae for the presence of hepatotoxins.

ISSN:0098-4108    

DOI:10.1080/15287398709530971

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The short‐term toxicity of sanguinarine, a benzophenanthridine alkaloid, and of two alkaloid extracts of Sanguinaria canadensis L. are presented. The acute oral LD50 in rats of sanguinarine was calculated to be 1658 mg/kg, and of the two alkaloid extracts, 1440 and 1250 mg/kg. The acute iv LD50 in rats of sanguinarine was found to be 29 mg/kg. No toxic effects were observed in rats fed up to 150 ppm sanguinarine in the diet for 14 d and in rats treated by gavage with up to 0.6 mg/kg body weight for 30 d. The acute dermal LD50 in rabbits was found to be greater than 200 mg/kg.

ISSN:0098-4108    

DOI:10.1080/15287398709530972

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The dermal penetration of14C‐ring‐labeled fenitrothion and aminocarb was determined in rats and rhesus monkeys. In monkeys, 49 ± 4% (tv2= 14 h) of the fenitrothion and 74 ± 4% (tv2= 25 h) of aminocarb were absorbed from the forehead, while 21 ± 70% (tv2= 17 h) fenitrothion and 37 ± 74% (tv2 = 31 h) aminocarb were absorbed from ventral forearm. Monkey forehead was 2.3 times and 2.0 times more permeable than the forearm for fenitrothion and aminocarb, respectively. In rats, 84 ± 72% (tv2= 20 h) of the fenitrothion and 88 ± 6% (tv2= 17 h) aminocarb was absorbed from the middorsal region. These results were corrected for incomplete excretion by intramuscular injections of fenitrothion in money, 95 ± 7% (tv2= 12 h), and rat, 69 ± 9% (tv2= 12 h), and aminocarb in monkey, 95 ± 14% (tv2= 8 h), and rat, 63 ± 6% (tv2= 15 h). These results suggest rapid dermal absorption of these pesticides in rats and monkeys and the use of these animal models for measuring dermal penetration is discussed.

ISSN:0098-4108    

DOI:10.1080/15287398709530973

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398709530956

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor