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Models for Assessing Risk of Occupational Hearing Loss, Final Report.

PB2004104023

Publication Date	2003
Personal Author	Fechter, L.
Page Count	14
Abstract	This research project was designed to determine the ability of chemical asphyxiants, carbon monoxide and cyanide, to potentiate noise induced hearing loss. Significant findings : (1) Carbon monoxide potentiates noise induced hearing loss (NIHL); (2) The lower bound benchmark dose for such potentiation lies between 200-300 ppm CO; (3) Carbon monoxide disrupts the relationship between increasing noise duty cycle for intermittent noise and increasing auditory impairment; (4) The potentiating effect of CO on NIHL can be reduced or blocked by administration of the free radical scavenger PBN but not by the glutamate receptor blocker, MK-801; (5) Direct measurement of free radicals in cochlear tissue shows a significant increase in free radicals with combined exposure to CO and noise, but no measurable change above baseline for CO and for noise given individually; and (6) Hydrogen cyanide produces a dose dependent increase in NIHL.
Keywords	Auditory defects Carbon monoxide Cyanide Occupational exposure Auditory perception Fire fighters Truck drivers Noise(Sound) Hydrogen cyanide Hair cells Concentration(Composition) Free radicals Cochlea Ear Chemical asphyxiants NIHL(Noise induced hearing loss)
Source Agency	National Institute for Occupational Safety and Health
Corporate Authors	Oklahoma Univ. Health Sciences Center, Oklahoma City.; National Inst. for Occupational Safety and Health, Washington, DC.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Washington, DC.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	200413

Models for Assessing Risk of Occupational Hearing Loss, Final Report.

Models for Assessing Risk of Occupational Hearing Loss, Final Report.
PB2004104023

Publication Date	2003
Personal Author	Fechter, L.
Page Count	14
Abstract	This research project was designed to determine the ability of chemical asphyxiants, carbon monoxide and cyanide, to potentiate noise induced hearing loss. Significant findings : (1) Carbon monoxide potentiates noise induced hearing loss (NIHL); (2) The lower bound benchmark dose for such potentiation lies between 200-300 ppm CO; (3) Carbon monoxide disrupts the relationship between increasing noise duty cycle for intermittent noise and increasing auditory impairment; (4) The potentiating effect of CO on NIHL can be reduced or blocked by administration of the free radical scavenger PBN but not by the glutamate receptor blocker, MK-801; (5) Direct measurement of free radicals in cochlear tissue shows a significant increase in free radicals with combined exposure to CO and noise, but no measurable change above baseline for CO and for noise given individually; and (6) Hydrogen cyanide produces a dose dependent increase in NIHL.
Keywords	Auditory defects Carbon monoxide Cyanide Occupational exposure Auditory perception Fire fighters Truck drivers Noise(Sound) Hydrogen cyanide Hair cells Concentration(Composition) Free radicals Cochlea Ear Chemical asphyxiants NIHL(Noise induced hearing loss)
Source Agency	National Institute for Occupational Safety and Health
Corporate Authors	Oklahoma Univ. Health Sciences Center, Oklahoma City.; National Inst. for Occupational Safety and Health, Washington, DC.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Washington, DC.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	200413