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Assessment of Peripheral, Central and Autonomic Nervous System Functions in Two Lead Smelters with High Blood Lead Concentrations: A Follow-Up Study

Yasushi FUJIMURA, et al

Department of Public Health, School of Medicine, University of Tokyo

Peripheral nerve conduction velocity. Distribution of nerve conduction velocities, Short-latency somatosensory evoked potential, Brainstem auditory evoked potential, Visual evoked potential, P300. R-R interval variability, Blood lead, Subclinical S. Araki, Department of Public Health, School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan
J Occup Healthyear1998Vol40No19-15

To examine the effects of lead on peripheral central and autonomic nervous system functions, the median and radial motor and sensory nerve conduction velocities (MCV and SCV), distribution of median nerve Conduction velocities (DCV), short-latency somatosensory, brainstem auditory and visual evoked potentials (SSEP, BAEP and VEP, respectively), event-related potential (P300), and electrocardiographic R-R interval variability (CVRR) were reassured once a month for 12 and 25 months in two male lead smelters with the first blood lead (BPb) concentrations of 105.6 microg/dl (Lead smelter 1) and 76.5 microg/dl (Lead smelter 2), respectively. The measurement were conducted a day before the workers underwent BPb measurement and lead mobilization test with 1-hr calcium disodium ethylenediamine tetraacetate infusion. The following results were obtained: (1) The delayed values for V 20-V90 velocities of the DCV, MCVs in the median and radial nerves, SCV in the median nerve, N13-N 20 interpeak latency of the SSEP, V latency of the BAEP, and P300 latency in Lead smelter 1 were significantly more frequent than the expected values in control subjects. (2) Also, the delayed values for V 60-V90 velocities of the DCV, MCV and SCV in the median nerve, and N9 latency of the SSEP in Lead smelter 2 were significantly more frequent than the expected values in control subjects. (3) The delayed values for MCVs in the median and radial nerves and N13-N20 interpeak (SSEP), V (BAEP) and P300 latencies in Lead smelter 1 were significantly more frequent than those in Lead smelter 2. (4) In the two lead smelters, the delayed values for V80 and 90 velocities of the DCV were significantly more frequent than those for V10 and V20 velocities. Thee data suggest that faster nerve fibres of the peripheral nerve are more sensitive to chronic lead exposure than slower nerve fibres are, and peripheral nerve function is more sensitive to Chronic lead exposure than central and autonomic nervous system functions.

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