Biomedical Engineering Reference
In-Depth Information
A total of 36 pregnant females/group were exposed to 0, 200, 1000, or
5000 ppm (0, 262, 1310, and 6552mg/m
3
) methanol vapors (reagent
grade) on GD 7-17 for 22.7 hours/day. Statistical significance of results
was evaluated by t-test, Mann-Whitney U test, Fisher's exact test, and/or
Armitage's
2
test.
In the prenatal portion of the NEDO (1987) study, reduced body weight
gain and food and water intake during the first 7 days of exposure were
reported for dams in the 5000 ppm group. On GD 20, 19-24 dams/group
were killed for evaluation of litters and individual fetuses. Adverse
reproductive and fetal effects were limited to the 5000 ppm group and
included an increase in late-term resorptions, decreased live fetuses,
reduced fetal weight, and increased frequency of litters with fetal mal-
formations, variations, and delayed ossifications. Malformations or vari-
ations included defects in ventricular septum, thymus, vertebrae, and ribs.
Postnatal effects of methanol inhalation were evaluated in the remain-
ing 12 dams/group that were permitted to deliver and nurse their litters.
Effects were only observed in the 5000 ppm group, and included a 1-day
prolongation of the gestation period and reduced post-implantation
survival, number of live pups/litter, and survival on postnatal day
(PND) 4. When the delay in parturition was considered, methanol
treatment had no effect on attainment of developmental milestones
such as eyelid opening, auricle development, incisor eruption, testes
descent, or vaginal opening. Therewere no adverse bodyweight effects in
offspring from methanol-treated groups. The weights of some organs
(brain, thyroid, thymus, and testes) were reduced in 8-week-old offspring
exposed to 5000 ppm methanol during prenatal development.
NEDO (1987) contains an account of a two-generation reproductive
study that evaluated the effects of pre- and postnatal methanol (reagent
grade) exposure (20 hours/day) on reproductive and other organ systems
of Sprague-Dawley rats. The F
0
generation (30 males and 30 females
per exposure group) was exposed to 0, 10, 100, or 1000 ppm from
8 weeks old to the end of mating (males) or to the end of lactation period
(females). The F
1
generation was exposed to the same concentrations
from birth to the end of mating (males) or to weaning of F
2
pups 21 days
after delivery (females). Males and females of the F
2
generation were
exposed from birth to 21 days old (one animal/sex/litter was exposed to
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