摘要:

The dermal toxicity of five commonly used organophosphate insecticides was investigated with a mouse intermittent self‐exposure model. Blood cholinesterases were monitored on d —3 and —1 before exposure and for 4–6 d during exposure to foliar residues. Responses were much greater in unmuzzled than in muzzled animals due to oral contamination. After two 10‐h exposures, muzzled mice showed log‐linear cholinesterase reponses across a wide range of foliar pesticide concentrations. Foliar pesticide levels that caused 50% depression in plasma or red blood cell cholinesterase were determined with log‐probit dose‐response analysis. The greatest cholinesterase responses for both emulsifiable concentrate and encapsulated formulations were found with diazinon, followed by parathion and methyl parathion. Azinphos‐methyl and mevinphos produced no significant responses in muzzled mice at maximal foliar concentrations. Symptomatology, food consumption, and body weight provided less sensitive indicators of response than cholinesterases. No consistent relation existed between the mouse intermittent self‐exposure toxicities and mouse dermal LD50 values. Use of data from acutely exposed animals to predict the hazard of intermittent foliar exposure appears inadvisable.

ISSN:0098-4108    

DOI:10.1080/15287398209530178

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Percutaneous penetration of [14C]parathion in mouse skin of nose, hind foot, scrotum, and tail was measured by recovery of excreted radioactivity relative to an intravenous dose. Oral ingestion was prevented by use of face muzzles and polyethylene rings at application sites. Penetration per unit area was in the following order (iv = 1.0): nose (0.8), scrotum (0.4), foot (0.3), and tail (0.3). Because of their greater surface area, tail and foot regions would contribute most to absorption in uniform ventral exposure. Daily recovery curves indicate apparent first‐order kinetics of elimination.

ISSN:0098-4108    

DOI:10.1080/15287398209530179

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Dermal LD50 values for five organophosphate insecticides were determined in mice by application of solutions to hind feet. Values were simultaneously generated for the ED50 (milligrams per kilogram) for both cholinesterase and acetylcholinesterase. Lethality was greatest with mevinphos, followed by parathion, methyl parathion, diazinon, and azinphosmethyl. LD50 values were higher than reported values for mice treated on shaved back skin. Cholinesterase ED50 values roughly agreed with LD50 values far mevinphos, parathion, methyl parathion, and azinphos‐methyl, but diazinon appeared much more inhibitory of blood than neuronal cholinesterase. Red blood cell and plasma cholinesterase activities were equally sensitive for all but mevinphos and diazinon.

ISSN:0098-4108    

DOI:10.1080/15287398209530180

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A method for estimating the proportion of mutagens in a sample of N compounds is developed. For this procedure to be applicable, there must be a statistically significant correlation between the number of mutagens in the sample and the sample size N. Sample size is treated as a random variable. A sequential sampling scheme is considered. In the first stage, compounds are identified and classified as mutagens, nonmutagens, or untested, as reported in the literature. In the second stage, all untested compounds are tested for mutagenicity. Since data of this type are not generally available, estimates of the proportions of compounds tested (p), tested and mutagenic (p1), and untested but mutagenic (p2) are developed from existing compilations. It is shown that there is a high, statistically significant correlation between the total number of mutagens in a sample and the sample size N. The proportion of mutagens in a sample for various values ofp,p1andp2is tabulated.

ISSN:0098-4108    

DOI:10.1080/15287398209530181

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Acute administration of sc doses of Cd (Img/kg*d, 3 or 6 d) to male golden hamsters resulted in a remarkable dose‐dependent increase of Zn in the liver and kidney. In contrast, Zn contents in the heart and testes showed a significant dose‐dependent decrease. No change was found in Zn contents of the bone. The correlation coefficients between contents of Cd and Zn in the liver and kidney were much higher in metallothionein fractions than in the corresponding whole organs. These results suggest that Cd induces the synthesis of metallothionein in the liver and kidney, leading to simultaneous accumulation of Cd and Zn in the organs; this in turn decreases the Zn contents in other organs, where weak or no induction of metallothionein synthesis takes place. Therefore Cd might induce Zn deficiency in humans or animals whose pool size and intake of Zn are marginal.

ISSN:0098-4108    

DOI:10.1080/15287398209530182

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Toxicity of the mycotoxin secalonic D (SAD) was examined histopathologically in rats. Dose response was studied by intragastric and intratracheal instillation, and SAD was given in suspension in Krebs‐Ringer phosphate solution at doses well below the reported LD50 values for both rats and mice. A full autopsy was performed on rats sacrificed 1–69 d after instillation. Responses differed markedly depending on the route of administration. Histopathological lesions were observed only in the lungs of rats receiving SAD intratracheally. At 24 h after treatment, the lungs of affected animals showed an acute polymorphonuclear reaction in the distal airways and adjacent alveoli and there was necrosis of airway epithelium. The latter resulted in the development of typical lesions of bronchiolitis obliterans. The initial acute inflammatory response in the peripheral lung became granulomatous at 3 d and the granulomas contained numerous foreign body type giant cells. Between 3 and 7 d the granulomas and bronchiolitis obliterans increased in severity; thereafter they tended to resolve. On termination of the experiment at 69 d there were a few small residual granulomas; however, no significant irreversible pulmonary injury was observed.

ISSN:0098-4108    

DOI:10.1080/15287398209530183

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398209530167

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor