Recommendations for the Prevention of Lead Poisoning in Children (1976) / Chapter Skim
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Appendix B: Toxicology of Lead in Experimental Animals
Appendix B: Toxicology of Lead in Experimental Animals
Pages 19-28
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From page 19... ...
In humans, the initial exposure to lead in paint usually coincides with ambulation and so begins at 10-12 months postpartum, while exposure to lead from some canned nutrients may begin at or shortly after birth. Neural Development in Experimental Animals - Bobbing and associates have demonstrated the vulnerability of the developing brain to moderate hyponutrition in experimental animals.2 Hyponutrition occiiring during the growth spurt produced a permanent reduction in both body and brain weight as well as behavioral changes.
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is substantially greater than the 5 to 10% absorption found in adults. Scientists seeking to evaluate the CNS effects of lead in human infants should select animals experiencing rates of brain growth and rates of intestinal absorption comparable to the human infant.
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From page 21... ...
Testing of animals for subclinical metabolic or functional effects, particularly those effects seen in the hematopoietic and neurologic systems, would be far more helpful in attempting to extrapolate the results of such studies to humans. RESULTS OF LEAD EXPOSURE IN YOUNG EXPERIMENTAL ANIMALS 13 The work of Brown appears to be an appropriate experimental model in terms of dose administered, age and neurodevelopmental stage.
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From page 22... ...
There were no data on the lead concentrations in maternal milk or suckling's blood. More recently, Michaelson and Sauerhoff, using a modification uf the lead-in-maternal milk feeding model, were able to produce hyperactivity, aggressiveness, tremors, and repetitive grooming behavior without extensive histopathology.65'66 The maternal milk contained approximately 25 ppm lead.
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Activity in the high-dose lead group was decreased by administration of 3 mg amphetamine/kg body weight. We believe that properly designed animal studies, simulating conditions in human infants, are needed to identify the relationships between external dose (dose of lead administered)
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From page 24... ...
48:757-767, 1973. Ed.: Douglas Gairdner and Roger Robinson.
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From page 25... ...
Weights for forebrain, cerebellum, and stem have been calculated as a percentage of adult value, and smooth lines drawn by eye through the points. IOO I" o -50 41 25 1 Forebrain Stem Cerebellum Birth Aqe (years)
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••• ^•s.^ " -.-r'rSRas 30 -20 AGE -10 A BIRTH 10 20 30 AGE FIGURE 7. Velocity of human brain growth (wet weight)
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From page 27... ...
FIGURE 8. The relationship of weight of parts of the brain to gestational age of rhesus monkeys.
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From page 28... ...
and Gruden, N.: The effect of milk diet on toxic trace element absorption in rats. Presented before the XVIII International Congress on Occupational Health, Brighton, England, Sept.
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