Teratologic evaluation of the magnesium sulfate adduct of [2,2'-dithio-bis-(pyridine-1-oxide)] in swine and rats

Maternal toxicity: a possible etiological factor in embryo-fetal deaths and fetal malformations of rodent-rabbit species

Data from animal teratology studies were surveyed to determine whether embryo-fetal mortality and fetal malformations result from a primary action of the agent on the conceptus or if they are secondary to maternal toxicity--a consequence of administration with high dose levels of test chemicals. A fairly strong association between embryo-fetal mortality and maternal toxicity was revealed by analysis of data from hamsters, mice, rats, and rabbits in 234 studies of chemical and physical agents, of which 83 were conducted at both maternotoxic and nonmaternotoxic doses, 94 only at maternotoxic doses, and 49 at nonmaternotoxic doses. In the above studies, only nine chemicals (four each in hamsters and rabbits and one in rats) were reported to induce embryo-fetal deaths at apparently nonmaternotoxic doses. These findings tend to suggest a contributory role for maternal toxicity in the induction of embryo-fetal deaths. The previously reported hypothesis that certain fetal defects in mice may perhaps be caused by maternal toxicity was also found to be true in a review of data on hamsters, rats, and rabbits. Salient maternal toxicity-associated fetal malformations were exencephaly, encephalocele, micro- or anophalmia, and fused ribs in hamsters and defective (fused, missing, or extra) ribs, vertebrae, and sternebrae, ex-, an-, or microphthalmia, and cleft palate in rats and rabbits. These malformations occurred at low frequencies, generally with no readily apparent dose-response relationship. Presumptive evidence indicates that embryo-fetal deaths, and the above-mentioned fetal malformations in experimental animals, which in published literature are presently attributed to chemical induction for a large number of chemicals, may be a consequence of maternal toxicity per se.

Percutaneous penetration of dipyrithione in man: effect of skin color (race)

A single chemical dose of dipyrithione (2,2'-dithiobispyridine-1,1'-dioxide), 4 or 12 micrograms/cm(2) (containing 1 micro Ci of 2-6-14C material), was applied to the ventral forearm (intact skin, methyl alcohol vehicle [MeOH]), forehead (intact and stripped skin; cosmetic cream and MeOH vehicle), and scalp (intact and stripped skin; shampoo and MeOH vehicle) of human (white and black) volunteers. The urinary excretion of 14C was measured over the 7-day study period. Percutaneous penetration data were corrected for incomplete urinary recovery using data from intravenous studies (Wedig et al). The results obtained in this study suggested: (1) means from the complete analysis indicated 34% less (p less than 0.02) absorbed by blacks; (2) less was absorbed by blacks than whites when seven out of seven means were compared within groups (p less than 0.02); (3) a difference (p less than 0.03) in penetration, blacks 47% lower than whites, between a cosmetic cream vehicle vs MeOH on the forehead; (4) on the scalp (MeOH vs shampoo vehicle) more was absorbed using MeOH (p less than 0.02); (5) no evidence of a significant difference in penetration was noted when (a) the various anatomic sites were compared or (b) intact skin was compared with stripped skin.