The AH Receptor and a Novel Gene Determine Acute Toxic Responses to TCDD: Segregation of the Resistant Alleles to Different Rat Lines

1999 ◽  
Vol 155 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Jouni T. Tuomisto ◽  
Matti Viluksela ◽  
Raimo Pohjanvirta ◽  
Jouko Tuomisto
Keyword(s):  
Ah Receptor ◽  
Novel Gene ◽  
Toxic Responses ◽  
Acute Toxic

Ah receptor: Dioxin-mediated toxic responses as hints to deregulated physiologic functions

2006 ◽  
Vol 72 (4) ◽  
pp. 393-404 ◽  
Author(s):  
Karl Walter Bock ◽  
Christoph Köhle
Keyword(s):  
Ah Receptor ◽  
Toxic Responses

To TEF or not to TEF? That is the question

1994 ◽  
Vol 13 (8) ◽  
pp. 576-577
Author(s):  
J. Battershill
Keyword(s):  
Risk Assessment ◽  
Signal Transduction Pathway ◽  
Quantitative Information ◽  
Tumor Promoter ◽  
Laboratory Animals ◽  
Ah Receptor ◽  
Coplanar Pcbs ◽  
Structure Activity ◽  
The Individual ◽  
Toxic Responses

Commercial polychlorinated biphenyls (PCBs) and environmental extracts contain complex mixtures of congeners that can be unequivocally identified and quantitated. Some PCB mixtures elicit a spectrum of biochemical and toxic responses in humans and laboratory animals and many of these effects resemble those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related halogenated aromatic hydrocarbons, which act through the aryl hydrocarbon (Ah)-receptor signal transduction pathway. Structure-activity relationships developed for PCB congeners and metabolites have demonstrated that several structural classes for compounds exhibit diverse biochemical and toxic responses. Structure-toxicity studies suggest that the coplanar PCBs, namely, 3,3',4,4'-tetrachlorobiphenyl (tetraCB). 3,3',4,4',5-pentaCB, 3,3',4,4',5,5'hexaCB, and their monoortho analogs are AH-receptor agonists and contribute significantly to the toxicity of the PCB mixtures. Previous studies with TCDD and structurally related compounds have utilized a toxic equivalency factor (TEF) approach for the hazard and risk assessment of polychlorinated dibenzo-p dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) congeners in which the TCDD or toxic TEQ = Σ([PCDFi X TEFi]n) + Σ([PCDDi x TEFi] n) equivalent (TEQ) of a mixture is related to the TEFs and concentrations of the individual (i) congeners as indicated in the equation (note: n = the number of congeners). Based on the results of quantitative structure-activity studies, the following TEF values have been estimated by making use of the data available for the coplanar and mono-ortho coplanar PCBs: 3,3',4,4'5-pentaCB,0.1; 3,3',4,4',5,5'-hexaCB,0.05 ; 3,3',4,4'-tetraCB,0.01; 2,3,3',4,4'-pentaCB,0.001 ; 2,3,4,4',5-pentaCB, 0.0001; 2,3,3',4,4',5-hexaCB,0.0003 ; 2,3,3',4,4',5'-hexaCB,0.0003; 2',3,4, 4',5-pentaCB,0.00005; and 2,3,4,4',5-pentaCB, 0.0002. Application of the TEF approach for the risk assessment of PCBs must be used with considerable caution. Analysis of the results of laboratory animal and wildlife studies suggests that the predictive value of TEQs for PCBs may be both species-and response-dependent because both additive and non-additive (antagonistic) interactions have been observed with PCB mixtures. In the latter case, the TEF approach would significantly overestimate the toxicity of a PCB mixture. Analysis of the rodent carcinogenicity data for assessment of PCB mixtures that uses cancer as the endpoint cannot solely utilize a TEF approach and requires more quantitative information on the individual congeners contributing to the tumor-promoter activity of PCB mixtures.

Histopathology of Acute Toxic Responses in Selected Tissues from Rats Exposed by Inhalation to Methyl Bromide

1987 ◽  
Vol 9 (2) ◽  
pp. 352-365
Author(s):  
MARK E. HURTT ◽  
KEVIN T. MORGAN ◽  
PETER K. WORKING
Keyword(s):  
Methyl Bromide ◽  
Toxic Responses ◽  
Acute Toxic

Acute toxic responses of embryo-larval zebrafish to zinc pyrithione (ZPT) reveal embryological and developmental toxicity

Chemosphere ◽  
2018 ◽  
Vol 205 ◽  
pp. 62-70 ◽  
Author(s):  
Ye Zhao ◽  
Yuyang Liu ◽  
Jing Sun ◽  
Hongtao Sha ◽  
Yu Yang ◽  
...  
Keyword(s):  
Developmental Toxicity ◽  
Zinc Pyrithione ◽  
Larval Zebrafish ◽  
Toxic Responses ◽  
Acute Toxic

Ah Receptor: Involvement in Toxic Responses

2005 ◽  
pp. 491-532 ◽  
Author(s):  
Thomas A. Gasiewicz ◽  
Sang-Ki Park
Keyword(s):  
Ah Receptor ◽  
Toxic Responses

Effect of Seasonal Photoperiod on Acute Toxic Responses of Juvenile Rainbow Trout (Salmo gairdneri) to Pulpmill Effluent

1978 ◽  
Vol 35 (10) ◽  
pp. 1388-1392 ◽  
Author(s):  
Donald J. McLeay ◽  
Michael R. Gordon
Keyword(s):  
Rainbow Trout ◽  
Blood Sugar ◽  
Threshold Effect ◽  
Tolerance Test ◽  
Temperature Tolerance ◽  
Toxicity Tests ◽  
Salmo Gairdneri ◽  
Jar Test ◽  
Toxic Responses ◽  
Acute Toxic

Acute toxic responses to bleached kraft pulpmill effluent were compared for groups of underyearling rainbow trout (Salmo gairdneri) reared under constant temperature and either a summer (16L:8D) or winter (8L:16D) photoperiod. Toxicity tests included a 96-h LC50 bioassay, a 4.5-h sealed-jar test, an 18-h temperature tolerance test, and a 4-h blood-sugar stress bioassay. For all tests the threshold-effect concentration of effluent was not affected by photoperiod. Median effective concentrations for the blood-sugar, temperature tolerance, and sealed-jar tests were, respectively, < 0.2, 0.4, and ~1.4 times the 96-h LC50 value for each fish group. Key words: Salmo gairdneri, photoperiod, BKME, acute toxicity tests, LC50, blood sugar, temperature tolerance, residual oxygen

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