Measurement Of Blood Lead Levels Research Articles

Hormonal Contraception and Blood Lead Levels in Inner-City Adolescent Girls

Study Objective Physiological states of estrogen deficiency can lead to bone demineralization. Lead is stored in bone and may be released into blood during demineralization. The contraceptive injection depomedroxyprogesterone acetate (DMPA) is associated with estrogen deficiency and bone demineralization and, we hypothesized, may be associated with toxic blood lead levels in adolescents at high risk for lead exposure. We sought to compare blood lead levels in inner-city adolescent girls using DMPA with levels in those using oral contraceptive pills (OCP) and those taking no hormones and to examine the influence of lead exposure and reproductive history on blood lead levels in the total sample. Design Cross-sectional survey of a clinical convenience sample. Setting Inner-city adolescent clinic in an academic medical center. Participants 174 females aged 13–21 years; 86% minority ethnicity. Interventions None Main Outcome Measures Measurement of blood lead levels and an 82-item questionnaire examining lead exposure and reproductive history. Results 28 subjects were using DMPA, 25 used OCPs, and 121 used no hormones. Mean blood lead level in the total sample of 174 was 1.6 μg/dL, SD = 1.1. Many subjects had environmental risk factors for lead exposure and 15% reported one or more past pregnancies. Mean blood lead levels for subjects with the various environmental and reproductive risk factors ranged from 1.2 μg/dL to 2.0 μg/dL and were not different from levels for subjects without such risk factors. Mean blood lead levels for subjects in the 3 hormonal groups were significantly different (2.1 vs. 1.2 vs.1.5 μg/dL in DMPA, OCP, and no hormone groups respectively, P = 0.007). We dichotomized the blood lead levels into “High” ≥4 μg/dL, or “Low” <4 μg/dL. We found that a significantly higher proportion of girls using DMPA (4/28) than those not using any hormone (2/121) had “High” levels ( P = 0.012). Conclusions Despite reported high-risk exposure to lead and the possibility of long-term accumulation of lead in bone, we did not find elevated blood levels in our sample. However, DMPA-treated girls were significantly more likely to have higher mean blood lead levels than OCP users and non-hormone users. In addition, DMPA users were more likely to have blood lead levels more than two standard deviations above the mean for the sample as a whole than untreated girls. Further studies are needed to examine low-level lead poisoning in adolescents and the consequences of contraceptive choices on bone health.

Manejo de la intoxicación por plomo en la niñez

This paper reviews the clinical management of children with lead poisoning. A first step is to define the measures to be used in their assessment and be aware of the limitations. Measurements of blood lead levels can be made on anticoagulated whole blood samples using either: atomic absorption spectroscopy or anodic stripping voltametry. However a more accurate method is fluorescent RX'ray of the skeleton or systematic biochemical tests of lead levels in urine. Remedies include elimination of lead in the environment, changes in children's behavior and dietary checks for adequate calcium and iron intake. Chelation therapy, using Ca edetate and succimer eliminates lead from the skeleton, which is then quickly excleted using a cathartic to help prevent re-absorption. Chelation may save lives where BLLs are very high. There is usually a short term reduction of BLLs with a subsequent rise. Serious cases may require repeat therapies. Chelation should be considered in children with BLLs > = 45 micrograms/dl. Chelation therapy reduces BLLs and associated symptoms. However cognitive decline may be irreversible, indicating that emphasis should be on prevention rather than cure. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

Lead Exposure at Uncovered Outdoor Firing Ranges

Excessive lead exposure in shooting instructors at indoor firing ranges and covered outdoor firing ranges has been documented. The City of Los Angeles assessed exposure of its full-time shooting instructors at uncovered outdoor ranges via air monitoring and blood lead-level measurements. Results of these tests revealed that significant lead exposure and absorption can occur at outdoor firing ranges. The use of copper-jacketed ammunition may decrease air lead levels and decrease lead absorption by range instructors.

Delta-Aminolaevulinic acid dehydratase as an index of the presence and severity of lead poisoning in acute and chronic lead exposure.

The activity of delta-aminolaevulinic acid dehydratase (ALA-D; porphobilinogen synthase) was measured in whole blood from a group of workers with acute exposure to lead and with low blood lead levels, a group of workers with chronic lead exposure and high blood lead levels, and a group of people without undue environmental lead exposure. The activity of ALA-D was reduced significantly at low blood lead levels only if undue exposure to lead had occurred, and was thus a reflection of low level lead poisoning. In chronic lead exposure the enzyme was not invariably reactivated fully with dithiothreitol, indicating more severe enzyme poisoning. The one lead worker with symptomatic lead poisoning had the most marked enzyme suppression. Measurement of both ALA-D activity and blood lead levels was more useful than the measurement of blood lead levels alone in the diagnosis and assessment of the severity of lead poisoning.

Studies on N2 cement in man and monkey—cement lead content, lead blood level, and histologic findings

N2 Normal and N2 Medical were analyzed for lead content and yielded a positive result. Blood lead level measurements were performed on four patients before and after root fillings made with N2 Normal or gutta-percha /Kloroperka-NØ. No detectable differences were found. After six months, the teeth were extracted and examined histologically. Inflammatory changes and particles of N2 cement were found in the pulp tissue. Pulpotomies were made in 20 teeth from five baboons, and N2 cement was applied to the wound surfaces of each. The teeth were extracted one month, one year, and two years later. Histologic examination showed particles of the N2 cement in vessels, macrophages, and multinuclear giant cells.

Die Bedeutung der Blei-Immissionsbelastung für Schwangere und Neugeborene im Ruhrgebiet

Systematic measurements of blood lead levels in samples from 176 mature and premature neonates and 59 mothers in the western Ruhr-Rhine area demonstrated that at least 30% of statistical variance in blood lead levels depended on lead immission at the mother's place of residence. The close correlation between neonatal and maternal blood lead levels was confirmed. Identical and non-identical twins had almost the same blood lead levels. Using a biological system for determining lead immission, blood lead levels in areas not covered by the present study can be prognosticated.