Uncertainties related to the assignment of a toxic equivalency factor for 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin

Analysis of the CYP1A1 mRNA Dose-Response in Human Keratinocytes Indicates that Relative Potencies of Dioxins, Furans, and PCBs Are Species and Congener Specific

“…This concordance indicates that RTFs could function not only in support of EC50-based REP values but also possibly substitute for REP values when a maximum response cannot be accurately determined. However, as noted by others (Howard et al, 2010;Sutter et al, 2006), REP values (and likewise RTFs) would not accurately predict responses of partial agonists at high doses, although the relevancy of potency differences at very high doses to endpoints of interest may be dubious. Furthermore, if the most potent dioxin-like PCB congener (i.e., PCB 126) does not always act as a full AHR agonist in human cells, then application of the TEF scheme to mixtures containing other less potent dioxin-like PCBs, previously demonstrated to act as very weak agonists or Single chemical nonlinear mixed-effects models with random effects allowing the baseline expression level and slope after the threshold to vary among donors.…”

Evaluation of the Lifespan of Fruit Fly Drosophila melanogaster Exposed to Dioxins

“…In a fifteen day study with female pregnant Sprague-Dawley rats which were orally treated with TCDD (10, 100 or 200 ng/kg body weight) resulted in that body size and sex ratio between the pregnant period of rats were not altered (Rebourcet et al, 2010). In many studies with laboratory animals, it has been reported that the toxicity of TCDD is very potent according to the other dioxins (Sutter et al, 2006). Experimental mice in a study conducted on that vary according to the gender of TCDD toxicity and toxic effects in male rats was lower, more accumulation in the tissues of the female of dioxins and stated that due to the longer halflife (USEPA, 2004;Pohjanvirta, 2009).…”

Detection of Persistent Organic Pollutants in Omental Adipose Tissue from Patients with Diffuse-Gastric Cancer: A Pilot Study

“…For instance, mice treated with TCDD or PCDD/HCDF all had hyperplasia in the fundus of glandular stomach [ 47 ]. Sub-chronic exposure to OCDD appears to cause effects similar to those observed following exposure to low levels of TCDD in a rat model [ 48 , 49 ], although with less potency in human cells [ 49 ]. TCDD, the most toxic compound among PCDD/F family, also triggers invasive processes in human gastric tumor cell lines [ 50 ].…”