Known human effects, definition

The definition of neurotoxicity also indicates a potential difference between the developing and the mature nervous system, to underscore the fact that developmental neurotoxicity is an important aspect of neurotoxicology. Most known human neurotoxicants are indeed developmental neurotoxicants.4 In most, but not all cases, the developing nervous system is more sensitive to adverse effects than the adult nervous system, as indicated, for example, by the most deleterious effects of ethanol, methylmercury, or lead when exposure occurs in utero or during childhood. Furthermore, the blood-brain barrier (BBB), which protects the mature nervous system from the entry of a number of substances, appears to be poorly developed at birth and during the first few years of life.6... 

Typical units for LDjq values are milligrams or grams of material per kilogram of body weight (mg/kg or g/kg, recall that 1 kg = 2.2 pounds). Never be exposed to an LD50 dose of a hazardous chemical- by definition, there is a 50% chance this will kill you and if you survive you are not going to be in good shape. Pay close attention to the permissible exposure level (PEL) instead. This is a more realistic determination of the maximum safe exposure to a material and is usually based on the known effects of the chemical on humans, rather than laboratory animals. 

At the present time, pheochromocytoma and intracranial lesions are the only causes of human hypertension which are definitely known to involve overactivity of the sympatho-adrenal system. However, presumptive evidence is accumulating to indicate that neurogenic factors may be involved in early essential hypertension, and it is possible that adequate adrenergic blockade early in the course of such hypertension may be effective in aborting its development. Only additional evidence regarding the etiology of essential... 

In humans the major and consistent effect is on the skin. Exposed people suffer from a severe form of acne, known as chloracne, after exposure to dioxin. Changes in the immune system have also been detected in the children exposed at Seveso in Italy and workers exposed at the Coalite plant in the UK. The latter had reduced levels of some immunoglobulins. There is no definitive evidence as to whether humans are more or less sensitive to dioxin than other mammals but the weight of evidence would suggest that they are less sensitive than many. 

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