Blood lead levels behavioural effects

Rabinowitz MB, Wang J-D, Soong W-T Children s classroom behavior and lead in Taiwan. Bull Environ Contam Toxicol 48 282-288,1992 Ratcliffe JM Developmental and behavioural functions in young children with elevated blood lead levels. Br J Prev Soc Med 31 258-264, 1977 Rigby EP Low lead levels and mental retardation (letter). Lancet 1 421,1977 Rogan WJ, Dietrich KN, Ware JH, et al The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead. N Engl J Med 344 1421-1426, 2001... 

Most of these studies have shown that blood lead values are invariably increased by exposure, but little or no health hazard has been adduced. This may be due to the fact that minor effects (e.g. behavioural ones), have not usually been investigated. Lansdowne et al. (1974) linked proximity to a lead smelter in London with increase in blood lead levels. There was however no link between lead and any measure of mental capability that was investigated, and any observed differences that were found could be related to social factors. Hebei et al, (1976) compared distance from a Birmingham battery factory with 11-plus examination scores and found that children who lived near the factory since birth scored more than those with a low lead-load or living in unpolluted areas. They also reported that this difference remained when adjustments were made for social class, birth rank and maternal age. 

The second type of effect has been seen in studies utilizing relatively small doses of lead and monitoring lead load by measuring blood lead levels. The results of these studies are harder to interpret, but overall they suggest a stimulation of catecholaminergic function at levels of lead comparable to those found in exposed humans. The results of low-dose experiments in which drug-elicited behaviour is studied are of particular importance in the context of such borderline effects. 

Ramsay, P. B., Krigman, M. R. and Morrell, P. (1980). Developmental studies of the uptake of choline, gaba and dopamine by crude synapsomal preparations after in vivo or in vitro lead treatment. Brain Res., 187, 383 Ratcliffe, J. M. (1977). Developmental and behavioural functions in young children with elevated blood lead levels. Br. J. Preventive Social Med., 31, 258 Reiter, L. W. (1977). Behavioral toxicology effects of early postnatal exposure to neurotoxins on development of locomotor activity in the rat. J. Occupational Med., 19, 201... 

McBride, W.G. (1984) Prospective study of health effects of lead in urban children. Paper presented at International Conference on Prospective Lead Studies, Cincinnati, Ohio, April McBride, W.G., Black, B.P. and English, B.J. (1982) Blood lead levels and behaviour of 400 preschool children. Med. ]. Australia, 2, 26-29 Mackie, A.C., Stephens, R., Townsend, A. and Waldron, H.A. (1977) Tooth lead levels in Birmingham children. Arch. Environ. Health, 32, 178-185 Mahaffey, K.R., Annest, J.L., Roberts, J. and Murphy, R.S. (1982) National estimates of blood lead levels United States, 1976-1980 association with selected demographic and socioeconomic factors. N. Engl ]. Med., 307, 149-159 Moore, M.R., Campbell, B.C., Meredith, P.A., Beattie, A.D., Goldberg, A. and Campbell, D. 

Ratcliffe, ].M. (1977) Development and behavioural functions in young children with elevated blood lead levels. Br. ]. Prev. Soc. Med., 31, 258-262 Reitan, R.M. (1966) A research program on the psychological effects of brain lesions in human beings. In Ellis, N.R. (ed.). International Review of Research in Mental Retardation, Vol. 1, pp. 153-218 (New York Academic Press)... 

Silva, P.A., Hughes, P., Crosado, B. and Faed, ]. (1984). A pilot study of blood lead levels, cognitive development and behaviour problems in 579 Dunedin eleven year old children. Presented at Workshop on Lead Research, University of Auckland Smith, M., Delves, T., Lansdown, R., Clayton, B. and Graham, P. (1983). The effects of lead exposure on urban children the Institute of Child Health/Southampton study. Dev. Med. Child Neurol, Suppl. 47... 

Hansen ON, Trillingsgaard A, Beese I, et al A neuropsychological study of children with elevated dentine lead level assessment of the effect of lead in different socio-economic groups. Neurotoxicol Teratol 11 205-213, 1989 Haritos NP Chronic lead intoxication a report of 21 treated cases at Children s Hospital. Clinical Proceedings of the Children s Hospital 17 110-115,1961 Harvey PC, Hamlin MW, Kumar R Blood lead, behaviour and intelligence test performance in preschool children. Sci Total Environ 40 45-60, 1984 Hawk BA, Schroeder SR, Robinson G, et al Relation of lead and social factors to IQ of low-SES children a partial replication. American Journal of Mental Deficiency 91 178-183, 1986... 

EEG measures were obtained from three sites during a passive sensory conditioning task of 35 trials. The data for more than a third of the subjects (particularly younger ones) were rejected for medical, technical and behavioural reasons, and a slow-wave analysis was carried out on the data obtained from 41 children. Two years later some of these children were followed up and valid data, based on 100 trials, were obtained for 28 children. A multivariate regression analysis was carried out to allow for possible effects of sex, age, SES and IQ, and to test for nonlinear effects of age and blood lead. These analyses showed that slow-wave voltage varied as a linear function of blood lead, but that the slope of this relationship varied with age. In children aged under 5, slow-wave voltage tended to be positive at lead levels below... 

One of the primary effects of Mn(II) deficiency is the increased susceptibility to convulsions or seizures which occurs in both ataxic and non-ataxic animals [369]. More recently, there has been increasing evidence that blood levels of Mn(II) are lower in epileptic than in normal patients [370-375]. One hypothesis for the biochemical basis of this effect in the CNS is that lower Mn(II) concentrations in the glial cytoplasm lowers glutamine synthetase activity, which leads to higher extracellular levels of the excitory L-glutamate. This results in a lower firing threshold for neurons with Glu-activated receptors [177]. Other effects of Mn(II) on the nervous system include changes.in the behaviour of cardio-pulmonary nerves [376], effects... 

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