Nervous-system responses of rats to subchronic inhalation of n- hexane and n-hexane plus methyl-ethyl-ketone mixtures.
Altenkirch-H; Wagner-HM; Stoltenburg-G; Spencer-PS
Klinikum Steglitz, Department of Neurology, FU Berlin, West Germany :1-21
The nervous system effects of continuous inhalation exposures to concentrations of n-hexane (110543) (HEX) or HEX plus methyl-ethyl- ketone (78933) (MEK) mixtures were investigated in male Wistar-rats. Long term effects of intermittent exposures to the mixtures were also examined. In experiment-A, the animals were exposed for 24 hours/day, 7 days/week for 9 weeks to 500 parts per million (ppm) HEX, 700ppm HEX, 300ppm HEX plus 200ppm MEK, 400ppm HEX plus 100ppm MEK, 500ppm HEX plus 200ppm MEK, or hydrocarbon filtered air (HFA). In experiment-B the animals were exposed 8 hours/day, 7 days/week, for 40 weeks to 700ppm HEX, 500ppm HEX plus 200ppm MEK, or HFA. Solvent exposed animals from experiment-A showed marked reductions in weight. Those treated with the mixture of compounds demonstrated excessive hypersalivation, frequent orange/red discoloration of the skin and fur, and narcosis. All solvent exposed animals demonstrated limb weakness commencing by evasion of the hindlimbs and resulting in paralysis. Histological examination showed hexacarbon specific axonal lesions in peripheral nerves, particularly tibial branches to calf muscles, and in the gracile tract at cervical levels of the spinal cord. Those who survived experiment-B did not give evidence of narcosis and no depressed body weights were evident. Fur discoloration was restricted to an orange/red collar around the neck and appeared more often in animals exposed to the mixture than to hexane alone. The author recommends that exposure to the combination of HEX and MEK be avoided and that appropriate warning accompany these products.
NIOSH-Grant; Neurological-system; Organic-solvents; Nervous-system-disorders; Laboratory-animals; Resins; Coatings; Lung-irritants; Hexanes; Ketones
Neuroscience Albert Einstein College 1410 Pelham Parkway Bronx, N Y 10461
NTIS Accession No.
Klinikum Steglitz, Department of Neurology, FU Berlin, West Germany
Yeshiva University, New York, New York