Biomedical Engineering Reference
In-Depth Information
required more time to locate nesting material from their home cages on
PND 10, suggesting a delay in normal behavioral development. The
second study, where rats were given a chronic high dose (15,000 ppm
7hours/day, GDs 7-19) of inhaledMeOH, also looked at litter parameters,
and in addition employed a variety of behavioral and cognitive tests for
motor activity, olfactory learning, behavioral thermoregulation, T-maze
learning, acoustic startle response, reflex modification, pubertal land-
marks, passive avoidance, and visual evoked potentials. The only
observed effect of MeOH was a decrease in fetal body weight, while
no effects were observed with any of the behavioral tests employed. A
single nonhuman primate study was conducted in the primate model
Macaca fascicularis, where pregnant monkeyswere exposed to a range of
concentrations of inhaled MeOH throughout the pre-mating and entire
gestational period (Burbacher et al., 1999). Postnatal behavior was
followed for 9 months after birth, employing neurodevelopmental behav-
ioral tests for early reflex response, motor development, spatial memory,
and social behavior. In utero MeOH exposure caused a decrease in
sensorimotor development only in male progeny in all treated groups.
MeOH exposure also demonstrated a failure for fetuses, in all treatment
groups and regardless of sex, to showpreference for novel stimuli as tested
by the Fagan Test of Infant Intelligence. No other tests were affected by
in utero MeOH exposure. Results of this study must be interpreted with
caution because of the small sample size used to assess the neuro-
behavioral outcomes, as random fluctuations could potentially account
for the statistical differences observed. On the other hand, sensorimotor
development is a complex developmental process, and the presence or
absence of an observed effect at this early stage does not preclude a
delayed onset neurotoxic effect later in life.
7.3.4 Carcinogenic Potential
Although the acute toxicity of MeOH in humans is well described, its
carcinogenic potential, similar to its teratogenic potential, is unknown.
It is similarly unknown which chemical species, whether MeOH and/or
any of its metabolites, might be a proximal toxicant. Formaldehyde
itself is a known carcinogen that causes nasopharyngeal cancer in
