Neurotoxicity chemicals and

Neurotoxic chemicals and motor neuropathy Chlorpyrifos, dichlorvos (DDVP), EPN, n-hexane, 2-hexanone, lead, lead chromate, lead II thiocyanate, leptophos, methamidophos, mipafox, omethoate, parathion, trichlor-fon, trichloronate, triorthocresyl phosphate Neurotoxic chemicals and sensorimotor neuropathy acrylamide, allyl chloride, arsenic and compounds, arsenic trichloride, calcium arsenate, carbon disulfide, dichloroacetylene, ethylene oxide, gallium arsenide, lead arsenate, mercuric chloride, mercuric nitrate, mercurous nitrate, mercury, nitrous oxide, phenyl arsine oxide, thallium and soluble compounds, thallous nitrate... 

The mechanisms by which many neurotoxic chemicals and chemical mixtures act remain unknown. Much of the knowledge regarding the... 

Autism certainly has a genetic factor associated with it. Studies, however, showing seasonal and annual variations in its prevalence, increased prevalence in urban versus rural areas, increased prevalence in areas with increased environmental pollution, and increased prevalence in offspring of mothers who have taken certain drugs, leads to the conclusion that there is a connection between maternal environmental exposure to neurotoxic chemicals and the prevalence of autism. 

Toxicology Exposure is by inhalation, and through skin absorption. Styrene is an irritant (eyes, mucous membranes and skin), a neurotoxic chemical, and a potential carcinogen. lARC concluded that there is limited evidence for the carcinogenicity of styrene both for animals and for humans, with liver damage [73]. 

Animal behavior has been dehned by Odnm (1971) as the overt action an organism takes to adjnst to its environment so as to ensure its survival. A simpler definition is the dynamic interaction of an animal with its enviromnent (D Mello 1992). Another, more elaborate, one is, the outward expression of the net interaction between the sensory, motor arousal, and integrative components of the central and peripheral nervons systems (Norton 1977). The last dehnition spells out the important point that behavior represents the integrated function of the nervous system. Accordingly, disruption of the nervous system by neurotoxic chemicals may be expected to cause changes in behavior (see Klaasen 1996, pp. 466-467). 

The effects of neurotoxic chemicals upon nerve action potential have been measured both in vertebrates and insects. Of particular interest has been the comparison... 

Many tests have been devised to provide quantitative measures of behavioral disturbances caused by neurotoxic chemicals. Tests have been devised that assess the effects of chemicals on four behavioral functions (D Mello 1992). These are sensory, cognitive, motor, and affective functions. However, because the entire nervous system tends to work in an integrated way, these functions are not easily separable from one another. For example, the outcome of tests focused on sensory perception by rats may be influenced by effects of the test chemical on motor function. 

New chapters Endocrine-Disrupting Chemicals and Their Environmental Impacts and Neurotoxicity and Behavioral Effects of Environmental Chemicals, the first of which is co-authored by R.W. Goodhead and Charles Tyler... 

HCFC-141b is a colorless, volatile liquid with a weak, ethereal odor. The vapor is heavier than air and can displace air in confined spaces. Additional chemical and physical properties are listed in Table 4-2. Experimental studies with human subjects and several mammalian species (monkey, dog, rat, mouse, and rabbit) were located. Animal studies addressed both acute and chronic exposure durations as well as neurotoxicity, genotoxicity, carcinogenicity, and cardiac sensitization. 

The front end of this tier approach is a screen, the functional observation battery (FOB) Gad (1982) or Irwin (1968) screen. This is the tool of choice for initial (and for most of the compounds covered by this volume, the only screen tests for) identification of potentially neurotoxic chemicals. The use of such screens, other behavioural test methods, or what are generally called clinical observations does, however, warrant one major caution or consideration. That is that short-term (within 24 hr of dosing or exposure) observations are insufficient on their own to differentiate between pharmacologic (reversible in the short term) and toxicological (irreversible) effects. 

Bracken WM, Sharma RP, Kleinschuster SJ. 1981. The effects of select neurotoxic chemicals on synaptosomal monoamine uptake and potassium-dependent phosphatase. Fundam Appl Toxicol... 

Carbaryl is perhaps one of the best studied of the major lawn chemicals, and evidence of health-related risks related to its use date as early as the late 1960s, when studies of the chemical revealed both its toxicity and its potential impact on animal (and potentially human) reproduction. In 1969 the U.S. Department of Health Education and Welfare recommended restrictions on the use of the chemical, owing to mounting evidence that it may be tetragenic (causing birth defects). Later research in the 1980s pointed towards the possible implication of carbaryl in neurotoxicity, brain function, and aggressive behavior. ... 

Kanada M, Miyagawa M, Sato M, et al. 1994. Neurochemical profile of effects of 28 neurotoxic chemicals on the central nervous system in rats (1) effects of oral administration on brain contents of biogenic amines and metabolites, hid Health 32 145-164. 

Enviromnent and health-related problems Bio varnishes , i.e. varnishes based on natural, renewable raw materials, were developed as close-to-nature alternatives (substitutes) i.a. as a reaction to the so-called German wood preservative scandal and indoor pollution due to chemical solvents. Nevertheless, they have until now had a relatively high content of volatile bio-organic solvents, which may cause irritations, allergic and neurotoxic reactions, and contribute to the formation of tropospheric ozone. 

There is worldwide concern about the potential neurotoxic effects of chemical substances but only a small fraction of chemicals have been adequately evaluated for neurotoxicity (WHO/IPCS 2001a). Of particular concern is the possibility of a relationship between exposures to low levels of environmental chemicals and effects on neurobehavioral development in children and neurodegenerative diseases in the elderly. 

Nonmetallic neurotoxins are frequently used in industry in manufacturing of chemicals and resins or as solvents. Some examples are hydrogen sulfide (which paralyzes specifically the nervous centers that control respiratory movement), carbon disulfide, -hexane, methyl -butyl ketone, and acrylamide. Exposure to all of these substances may occur through inhalation of vapors. In addition, carbondisufide and acrylamide may enter the system by dermal absorption. -Hexane and methyl -butyl ketone are not toxic by themselves but are activated by cytochrome P-450 to the neurotoxic hexanedione (CH3COCH2CH2COCH3). 

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