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Title: Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects

Abstract

The effects of lead exposure on heme synthesis in workers with subclinical responses and in controls were evaluated. delta-Aminolevulinic acid dehydratase (ALA-d) correlated significantly with blood lead levels in the control group but not with those in the exposed group. Free erythrocyte protoporphyrin correlated significantly with blood lead levels in the exposed group but not with those in the controls and was found to be a good indicator of blood lead history among exposed persons. Hemoglobin values determined at initial employment were not statistically different from those determined during the baseline test for a group of 12 workers with a maximum blood lead level of 86 micrograms/100 ml during their exposure history. The effect such heme inhibition may have on other body functions is uncertain.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
School of Public Health, UCLA
OSTI Identifier:
5510062
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Occup. Med.; (United States); Journal Volume: 24:2
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; HEME; BIOSYNTHESIS; INHIBITION; LEAD; ABSORPTION; BIOLOGICAL EFFECTS; HEMOGLOBIN; KETO ACIDS; OXIDOREDUCTASES; PERSONNEL; PROTOPORPHYRINS; CARBOXYLIC ACIDS; ELEMENTS; ENZYMES; GLOBIN; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; METALS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PIGMENTS; PORPHYRINS; PROTEINS; SYNTHESIS 560306* -- Chemicals Metabolism & Toxicology-- Man-- (-1987)

Citation Formats

Valentine, J.L., Baloh, R.W., Browdy, B.L., Gonick, H.C., Brown, C.P., Spivey, G.H., and Culver, B.D. Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects. United States: N. p., 1982. Web.
Valentine, J.L., Baloh, R.W., Browdy, B.L., Gonick, H.C., Brown, C.P., Spivey, G.H., & Culver, B.D. Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects. United States.
Valentine, J.L., Baloh, R.W., Browdy, B.L., Gonick, H.C., Brown, C.P., Spivey, G.H., and Culver, B.D. 1982. "Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects". United States. doi:.
@article{osti_5510062,
title = {Subclinical effects of chronic increased lead absorption--a prospective study. Part IV. Evaluation of heme synthesis effects},
author = {Valentine, J.L. and Baloh, R.W. and Browdy, B.L. and Gonick, H.C. and Brown, C.P. and Spivey, G.H. and Culver, B.D.},
abstractNote = {The effects of lead exposure on heme synthesis in workers with subclinical responses and in controls were evaluated. delta-Aminolevulinic acid dehydratase (ALA-d) correlated significantly with blood lead levels in the control group but not with those in the exposed group. Free erythrocyte protoporphyrin correlated significantly with blood lead levels in the exposed group but not with those in the controls and was found to be a good indicator of blood lead history among exposed persons. Hemoglobin values determined at initial employment were not statistically different from those determined during the baseline test for a group of 12 workers with a maximum blood lead level of 86 micrograms/100 ml during their exposure history. The effect such heme inhibition may have on other body functions is uncertain.},
doi = {},
journal = {J. Occup. Med.; (United States)},
number = ,
volume = 24:2,
place = {United States},
year = 1982,
month = 2
}
  • The effects of lead exposure on heme synthesis in workers with subclinical responses and in controls were evaluated. delta-Aminolevulinic acid dehydratase (ALA-d) correlated significantly with blood lead levels in the control group but not with those in the exposed group. Free erythrocyte protoporphyrin correlated significantly with blood lead levels in the exposed group but not with those in the controls and was found to be a good indicator of blood lead history among exposed persons. Hemoglobin values determined at initial employment were not statistically different from those determined during the baseline test for a group of 12 workers with amore » maximum blood lead level of 85 ..mu..g/100 ml during their exposure history. The effect such heme inhibition may have on other body functions is uncertain.« less
  • Seventy workers exposed to lead for at least one year and 35 control workers have been enrolled in a prospective study of possible neurologic effects of chronic lead absorption at or below the current standard of 80 ..mu..g per 100 ml whole blood. The study design is described in detail. Initial results of analysis of lead-related symptoms from baseline studies indicate few differences between the exposed and nonexposed workers. The majority of differences were for central nervous system (CNS) symptoms and muscle or joint pain. Little correlation was found between symptom reporting and indices of lead absorption. The evidence suggestsmore » that factors other than lead absorption itself may be important in symptom reporting.« less
  • This report summarizes the results of baseline neurologic testing in a group of apparently healthy workers from a secondary lead smelter and a group of controls from nearby aluminum processing plants. The test battery included a standard neurologic examination, nerve conduction measurements, quantitative oculomotor function tests and detailed audiologic studies. Lead workers and controls were intermixed so that the examiners were unaware of the status of any individual being tested. Although the lead workers reported significantly more neurologic symptoms than the controls, relatively few differences were found on quantitative neurologic testing. Decreased deep tendon reflexes occurred more frequently in themore » lead workers than in the controls (22% vs 11%) but the difference was of borderline significance (p = 0.06) and other signs of peripheral neuropathy occurred with equal frequency in both groups. The mean motor conduction velocity and sensory latency measurements were not significantly different in the lead workers and in the controls and, of the six oculomotor function measurements, only the mean accuracy saccadic eye movements was significantly (p < 0.01) different in the two groups. High frequency hearing loss occurred with equal frequency and severity in both groups, consistent with the level of noise exposure in the lead and control plants.« less
  • Subclinical central and peripheral nervous system dysfunction among lead-exposed workers was studied by measuring short-latency somatosensory evoked potentials (SSEP) and maximal motor and sensory nerve conduction velocities (MCV and SCV) following stimulation of the median nerve at the wrist. The examinations were conducted in 20 gun-metal foundry workers exposed to lead, zinc, copper, and tin, with blood lead (BPb) concentrations of 16 to 64 micrograms/dl (mean, 42 micrograms/dl). The interpeak latency of SSEP in the cervico-spino-bulbar region (N9(Erb)-N13 latency) was significantly prolonged, and the MCV and SCV in the forearm were significantly slowed. Multiple regression analysis revealed that the yieldmore » of urinary lead following challenge with calcium disodium ethylenediamine tetraacetate (CaEDTA) and packed red blood cell volume were the major factors associated with the prolongation of SSEP latency in the cervico-spino-bulbar region. Similarly, the interpeak latency in the upper central nervous system (N13-N20 latency) was inversely related to the zinc concentration in erythrocytes; latency up to the Erb's point (N9(Erb) latency), which reflects conduction time in a long pathway of the sensory median nerve, was inversely related to urinary zinc level; the MCV and SCV in the palm were positively related to erythrocyte zinc concentration and plasma copper concentration, respectively. These findings suggest that the subclinical neurophysiological effects of lead occur not only in peripheral nerves but also in the central nervous system. It appears that zinc antagonizes the central and peripheral neurologic dysfunction caused by lead; similarly, copper antagonizes the peripheral sensory nerve dysfunction.« less
  • Not all people exposed to the same level of a hematological toxin will develop clinical problems. Since there is an almost infinite combination of both exogenous and endogenous factors which might increase susceptibility to a toxin, it is only practical to test these variables through the use of well-defined in vitro systems. In the present study we studied the inhibitory effect of ethanol (0.1 M), lead (1 x 10/sup -4/ M), and benzene (0.1 M) on in vitro rabbit reticulocyte protein and heme synthesis, in iron-repleted and iron-depleted cells. The data clearly demonstrate that there is greater inhibition of totalmore » protein and heme synthesis by any one of these agents in iron-depleted cells. The inhibition with any of these inhibitors is additive with that of iron depletion. It appears, therefore, that people with iron deficiency might be at greater risk to develop hematological toxicity when exposed to ethanol, lead, or benzene.« less