Toxicants

Question 1

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Answer 1

produced during the production and/or combustion of certain chlorinated organic chemicals

Question 2

nitrites

Answer 2

in some people with the unusual phenotype of the autosomal recessive trait of a deficiency in NADH-cytochrome b5 reductase activity, nitrites oxidize the iron in hemoglobin to produce methemoglobin, which is incapable of carrying oxygen to tissues

Question 3

troglitazone

Answer 3

type II diabetes drug pulled from the market due to fata hepatotoxic response in patients who lacked functional genes for 2 forms of glutathione-S-transferase (GSTM1 and GSTM2) as well as possibly genetic differences in human lymphocyte angtigen (HLA) genetic loci

Question 4

diethylstilbestrol (DES)

Answer 4

daughters of mothers who took DES during pregnancy have a greatly increased risk of developing vaginal cancer in young adulthood (approx. 20 to 30 years post in utero exposure)

Question 5

organophosphate (OP) insecticides

Answer 5

delayed neurotoxicity is observed after exposure to some OP insecticides that act by covalen tmodification of an enzyme referred to as neuropathy target esterase (NTE), a neuronal protein with serine esterase activity

binding of OP to NTE initiates degeneration of long axons in the peripheral and CNS

effect can be seen immediately or be delayed at least several days after exposure

e.g., triorthocresylphosphate (TOCP)