Developmental damage

T.A. Slotkin, Brain developmental damage occurs from common pesticide Dursban (chlorpyrifos). Environ. Health Perspect. 107(suppl. 1) 1999. 

The most developmental damage to humans has been activated by alcoholic beverages, followed by smoking. The embryo-damaging effect of alcohol (ethanol) has been well investigated and pubUshed in many epidemiological studies. Especially babies from alcohoUc women show severe developmental defects. The documented effects are anatomical deformations and especiaUy mental and cognitive disorders. 

Carbon monoxide is also a well-known teratogenic compound for humans. The impact of carbon monoxide on the embryo or fetus is one reason for the developmental damage of smoking. 

Objective evidence of decreased human fertility is therefore difficult to obtain. In contrast to developmental damage, fertility of both men and women can be affected, and in the scientific community it is accepted that the number and quality of sperms is influenced in particular by external (e. g., stress) and internal factors (e. g., psychological variations). Effects on spermatogenesis (sperm maturation) can have various causes, and chemicals can of course activate these effects. In contrast, the ovum is much better protected against external influences. 

Substances are classified as toxic to reproduction if they can cause developmental damage under conditions where no maternal toxicity can be observed. In order to prevent abnormal animal experiments, no higher dosage than the limit threshold of 1000 mg kg (oral) should be tested. On the other hand classification has been done using dosages with a maternal toxicity, if the developmental effects were very severe and should be communicated. 

Category 1 Substances which have led to developmental damage in humans. 

Category 2 Substances which had shown developmental damage in animal studies. 

Category 3 Substances which are suspected of having developmental damaging properties. 

In tests of excessive amounts of boric acid in animals, this substance is seen to cause fetal and developmental damage. It is added to the bouncing clays for its flame-retardant and preservative properties. The boric acid content of toys must be greatly reduced - or the substance should not be used in them at all. 

We have equated cerebral T3 deficiency with developmental damage. We have no direct proof for this during the fetal period, except for decreased brain weight and DNA Others have, however, shown permanent CNS damage in the progeny of LID rats using diets which were more... 

Children sometimes differ from adults in their susceptibility to hazardous chemicals, but whether there is a difference depends on the chemical (Guzelian et al. 1992 NRC 1993). Children may be more or less susceptible than adults to health effects and the relationship may change with developmental age (Guzelian et al. 1992 NRC 1993). Vulnerability often depends on developmental stage. There are critical periods of structural and functional development during both pre-natal and post-natal life and a particular structure or function will be most sensitive to disruption during its critical period(s). Damage... 

Booze RM, Mactutus CF. 1990. Developmental exposure to organic lead causes permanent hippocampal damage in Fischer-344 rats. Experientia 46 292-297. 

The long-term consequences of neonatal exposure to triethyllead were examined with respect to the development of the central nervous system of rats138. The studies of the developmental exposure to triethyllead lead to the conclusion that this compound causes permanent hippocampus damage (neurotoxicity) in rats. 

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