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PubMedDate not supplied

[Differentiation of the abnormal QS complex in V1-V2 leads of standard electrocardiogram by using Frank's system of leads].

Frank's orthogonal system of leads x, y z was applied for electrocardiographic differentiation of the abnormal QS complex in V1-V3 leads of the standard electrocardiogram. Absence of the physiological Q wave in z+ lead of Frank evidences always presence of focal myocardial lesion in the anterior wall and this feature was used for electrocardiographic differential diagnosis of abnormal QS complex appearing as a result of recording of intraventricular potentials against actual focal myocardial lesion. The reported study was done in 37 patients with QS complex in V1-V3 leads in standard electrocardiogram. In 28 patients absence of the Q wave was noted in the z+ lead and presence of a scar in the anterior wall in tow-dimensional echocardiography, and in to patients presence of scar was confirmed additionally in radioisotope studies, and in one case on autopsy. In 9 patients the abnormal QS complex in V1-V3 leads was caused by recording of intraventricular potentials since in the z+ lead of Frank the Q wave was always present. Echocardiographic investigation demonstrated normal contractility of the anterior wall.

Action Potentials↗
PubMed1985

Elimination kinetics of blood lead in workers with chronic lead intoxication.

Blood lead elimination half-lives were determined for 65 patients with occupational chronic lead intoxication who were removed from exposure, treated with intravenous EDTA, and followed for periods of up to 2,419 days. The median overall blood lead elimination half-life was 619 days in patients with normal renal function and 1,907 days in patients with renal impairment. Slow-phase elimination half-lives in patients followed for longer than 5 years ranged from 1,658 to 7,189 days. Blood lead concentrations declined during periods of chelation with a mean half-life of 7 days and rebounded to near prechelation concentrations following termination of chelation with a mean doubling time of 27 days. The overall blood lead elimination half-life was positively associated with length of follow-up (p less than 0.001), age (p = 0.04), and duration of exposure (p = 0.02), but was not associated with the initial blood lead concentration following cessation of exposure or the total amount of EDTA received.

Adult↗
PubMed1981

[Contamination of foods and feeding stuffs from selected areas of the district of Erfurt with lead and cadmium. 2. Burden in agricultural products in the effective range of a lead emitter as compared to a control area].

Using the inverse voltammetric method already described (cf. Part I), the authors determined the lead and cadmium contents in 126 forage samples and 86 cereal samples from the surroundings of a lead emitter (area A) and from the control area B. To assess the heavy metal burden in forage plants at different growth stages, 33 samples of plants taken from both areas at the first stage of growth, not yet used for feeding, were analyzed. The lead burdens in the samples from area A varied with the distance from the emitter, a works which processes pure lead. 20 of the 87 forage samples from this area exhibited lead contents greater than 10 mg/kg of dry matter. 11 of the 55 cereal samples (grains) there taken contained more than 0.5 mg of lead/kg of fresh matter. As expected, there was no correlation between the cadmium values and the lead contents. These results are compared with those obtained from samples from the control area (39 forage samples and 31 cereal samples). Conclusions are drawn as to the agricultural use of land in the area of the emitter.

Agriculture↗
PubMed1981

Relationship between lead concentration in blood and the activities of erythrocyte pyrimidine 5'-nucleotidase and delta-aminolevulinate dehydratase in the mice exposed to lead.

The relationship between the activities of both pyrimidine 5'-nucleotidase (Py5N) and delta-aminolevulinate dehydratase (ALA-D) in erythrocytes and the concentration of lead in blood was investigated in the mice which were given ad libitum a drinking water containing lead of 10 to 500 ppm, for 30 days. From these results, it was demonstrated that the erythrocyte Py5N activity is inhibited by lead and its activity level is negatively correlated with the concentration of lead in blood (r = -0.78). In addition, it was suggested that the erythrocyte Py5N activity is a better indicator in the exposure to relatively high lead concentration while the ALA-D is a more sensitive indicator for evaluating the lead exposure of low and moderate levels.

5'-Nucleotidase↗
PubMed1980

Acute lead poisoning of the pigeon induced by single, intraperitoneal administration of lead acetate.

A single dose of lead acetate (either 30 mg/kg or 150 mg/kg) was intraperitoneally (i.p.) administered to adult feral pigeons, Columba livia var and the effects of calcium disodium ethylenediamine tetraacetate (CaNa2EDTA), (0, 150, 300, 600 mg/kg), administered i.p. twice a week in the ensuing period were observed. Lead acetate caused dose related mortality and decreases in weight, hematocrit and delta-aminolevulinic acid dehydratase activity (ALA-D). Acute toxicity of lead acetate in the pigeon, when given intraperitoneally, appeared approximately equivalent to that in the rat and mouse in terms of LD50. Blood lead (blood Pb) levels observed during the lethal stage were five to ten times less than those reported for chronic oral lead poisoning in the pigeon. Biological implications of elevated levels of blood Pb observed in the feral pigeon in the urban Tokyo area are discussed. CaNa2EDTA induced dose related recovery in ALA-D in 30 mg/kg group, and reduction of blood Pb levels in the group dosed with 150 mg/kg of lead acetate.

Animals↗
PubMed1978

Experimental lead encephalopathy in the suckling rat: concentration of lead in cellular fractions enriched in brain capillaries.

Five-day old rats subjected to short-term (2-day) lead exposure by gastric gavage of aqueous lead acetate at the highest non-lethal dosage (1mgPb/g body weight/day) developed a hemorrhagic encephalopathy. Capillaries and microvessels isolated from brains of these rats showed abnormal morphology consisting of an increased number of irregularly dispersed endothelial nuclei and swollen, vacuolated endothelial cells. Lead was concentrated in isolated brain capillary-microvessel fractions, as demonstrated by both atomic absorption and 210Pb tracer methods. When lead exposure was continued for 20 days (at the maximal dosage regime compatible with a 60% survival rate), the rats recovered from the initial encephalopathy and capillaries and microvessels isolated from brains of these rats appeared morphologically normal. This recovery occurred despite continued high levels of lead in the blood and in the isolated capillary-microvessel fractions, suggesting that, as capillary endothelial cells mature, they are able to adapt to the presence of large amounts of lead.

Animals↗
PubMed1993

Reference intervals for blood lead and evaluation of zinc protoporphyrin as a screening test for lead toxicity.

We evaluated, retrospectively, 2921 blood samples for the distribution of blood lead values in children below age 16, and in adult female and male subjects. An upper reference value for children and females at 0.48 mumol/L, and for males at 0.72 mumol/L is used. Over 70% of the adult males and > 80% of the children and adult females were within these reference limits, and considered to be at low risk for lead toxicity. The diagnostic utility of zinc protoporphyrin (ZPP) to screen for a positive blood lead result was evaluated using receiver operating characteristic (ROC) curves and likelihood ratios (LR). These studies confirmed that ZPP was insensitive for the detection of elevated blood lead at the critical thresholds of 0.48-1.21 mumol/L in children and adult females with subclinical lead poisoning. ZPP was more diagnostically useful for screening the higher lead-exposed adult male occupational worker.

Adolescent↗
PubMed1985

Condition and type of housing as an indicator of potential environmental lead exposure and pediatric blood lead levels.

Environmental evaluations in a prospective behavioral study of children with blood lead levels up to about 50 micrograms/dl were performed by an intensive environmental survey and by exterior visual evaluation of housing quality. Serial blood lead values for infants in the study were compared to exterior housing type and quality, which itself was also compared with results of the intensive environmental evaluation. Five housing condition and type categories were defined: public housing; private housing (satisfactory, deteriorated, and dilapidated); and rehabilitated private housing. In this interim report on the first subset of available data, the housing categories were found to differ in paint and environment dust lead levels, with public and rehabilitated housing having lowest values. Blood lead concentrations of children differed across housing categories as early as 6 months of age, with children residing in public housing having lowest levels, followed by those in rehabilitated housing. The spread in mean blood lead concentrations among the housing quality categories increased with increasing age of the children. Housing category accounted for over one-half of the blood lead variability in 18-month-old children.

Dust↗
PubMed1985

Methodological issues in modeling the relationship between low-level lead exposure and infant development: examples from the Boston Lead Study.

This paper addresses several methodological issues relevant to an assessment of the association between low-level lead exposure and early development. In particular, we discuss methods for choosing, from a large pool of candidates, the covariates to control when estimating this association. We examine the issue of confounding and explain why adjusting increased, rather than decreased, the estimate of the association between blood lead level and development at 6 months of age in our sample. A step-by-step description of our strategy for model building is presented. Finally, we demonstrate the robustness of the findings by showing that the magnitude and standard error of the estimated lead effect is not affected appreciably by the method of selecting covariates to be controlled for or by the characterization of lead as a continuous, ordinal, or dichotomous variable. Although these issues arose in the course of analyses of data collected by the Boston lead study (D. Bellinger, H. Needleman, A. Leviton, C. Waternaux, M. Rabinowitz, and M. Nichols (1984), Neurobehav. Tox. Teratol., 6, 387-402), they apply to other current prospective lead studies as well.

Analysis of Variance↗
PubMed1990

Lead intake and blood lead in two-year-old U.K. urban children.

A comprehensive study of a group of 2-year-old urban children (n = 97), designed to provide quantitative information simultaneously for lead intakes via all identified pathways, has been carried out in Birmingham (U.K.). Results showed that for children whose blood levels and exposure to environmental lead were within the normal range for the U.K., blood lead concentration was significantly related to a combination of house dust lead loading and an overall rate of touching objects, to water lead concentration and to the parents' smoking habits. On the basis of assumptions used by the Royal Commission on Environmental Pollution (RCEP), the estimated average total uptake of lead was 36 micrograms day-1; of this, 97% was from ingestion from dust, food and water and only 3% from inhalation.

Air Pollutants↗
PubMedDate not supplied

Influence of removal from occupational lead exposure on blood and saliva lead concentrations.

Samples of total blood and unstimulated mixed saliva were obtained from 5 male workers occupationally exposed to lead at various time intervals after removal from their work environment. Initial blood lead concentrations were elevated in all workers and then slowly decreased upon removal. Lead concentrations in saliva fell much more abruptly than those in blood, the saliva half-lives being estimated at 5-7 days. Temporary return to work in 2 workers resulted in relatively marked increases of salivary lead concentrations. These results suggest that salivary lead is closely related to recent lead exposure.

Environmental Exposure↗
PubMed2005

Evaluation of lead hazard control treatments in four Massachusetts communities through analysis of blood-lead surveillance data.

This study utilized existing blood-lead surveillance data and records of housing properties treated for lead hazard control (LHC) in order to investigate the effectiveness of LHC treatments performed in four Massachusetts communities (Boston, Cambridge, Malden, and Springfield). This research is part of the US Department of Housing and Urban Development's (HUD) overall program evaluation strategy for assessing the effectiveness of their LHC Grant Program. Childhood blood-lead levels (BLLs) in housing units that were treated through HUD's LHC Grant Program were compared to BLLs in untreated matched control housing units. Data from multiple sources-local housing departments, local tax assessor departments, and the Massachusetts Department of Public Health-were linked to identify similar sets of treated and untreated dwellings. Geometric mean BLLs from before and after treatment were compared for the two sets of housing. Ten years of blood-lead surveillance data for children living in the selected dwellings were analyzed using log-linear mixed models and logistic regression models. Results indicate a 50% decline in BLLs in treated homes, a significantly larger decline than in untreated homes after adjusting for the general downward trend in BLLs observed in the general population for the last several years. Data show that homes that received HUD LHC treatments had children with blood-lead levels that declined twice as fast as in similar untreated homes. These findings show that LHC efforts are successful in reducing children's blood-lead levels.

Child↗
PubMed2005

Blood lead levels and risk factors for lead poisoning in children and caregivers in Chuuk State, Micronesia.

Lead poisoning is a preventable environmental disease. Children and developing fetuses are especially vulnerable; even low blood lead levels (BLLs) are linked with learning and behavioral problems. We assessed children's and their caregivers' BLLs and risk factors for lead exposure in Chuuk State, Federated States of Micronesia. Children aged 2-6 years were randomly selected within 20 randomly selected villages. Children and caregivers provided venous blood, and caregivers offered information about possible risk factors for lead exposure. Mean BLLs were 39 microg/l for children and 16 microg/l for caregivers. Children with BLLs of > or = 100 microg/l (elevated) were 22.9 (95% CI: 4.5-116.0) times more likely to have a caregiver with an elevated BLL, 6.2 (95% CI: 1.4-27.3) times more likely to live on an outer island, and 3.4 (95% CI: 1.7-6.9) times more likely to have a family member who made lead fishing weights than did other children even after controlling for age and sex. For children, 61% of elevated BLLs could be attributed to making fishing weights. Caregivers with elevated BLLs were 5.9 (95% CI: 1.5-23.7) times more likely to live in a household that melted batteries than other caregivers even after controlling for age and education. For caregivers, 37% of the elevated BLLs could be attributed to melting batteries. The association of elevated BLLs in children and their caregiver suggests a common environmental exposure. Melting batteries to make fishing sinkers is a preventable source of lead exposure for children and their caregivers in Chuuk. Published by Elsevier GmbH.

Adult↗
PubMed1988

Ultrastructural aspects of the small intestinal lead toxicology. Part II. The small intestine goblet cells of rats during lead poisoning.

The purpose of the present study was to evaluate the detoxification significance of the small intestinal goblet cells in rats on prolonged treatment with 0.01% lead acetate in the drinking water. These goblet cells were analysed using a submicroscopic demonstration of heavy metals with the sulphide silver method and the X-ray microanalysis probe. Male Wistar rats, weighing 80 g, were sacrificed after 2, 30 and 60 d of exposure to oral administration of lead. The small intestines were perfused with Sörensen buffer with H2S, then blocks of tissue were removed from the border between the duodenum and jejunum and processed for transmission electron microscopy according to Grzybek (3) and Dancher (2). At first the silver containing salt precipitates were distributed in the extracellular space between epithelial cells after 2 d of the experiment. Treatment of rats with lead acetate for 30 d produced the characteristic appearance of the goblet cells at the electron microscopic level. The presence of lead in conjunction with the goblet cell membrane has been observed. If administration of lead to rats is continued longer than 30 d, in the mucus droplets located in the cytoplasm of goblet cells some deposits of silver salts may be demonstrated. For the electron probe X-ray microanalysis the bulk specimens were prepared using a critical point drying apparatus. The specimens were scanned along a line on the villous surface parallel to its long axis. The X-ray studies indicated that accumulation of lead in the epithelial cells increased during the time of experiment.

Animals↗
PubMedDate not supplied

Dependence of apparent blood lead half-life on the length of previous lead exposure in humans.

The expected relationship between the apparent half-life of blood lead (PbB) and the length of previous exposure is compared with the observed relationship in a group of workers on strike from a primary smelter where they had been employed for from a few months to ten years. Within this group, the apparent PbB half-life was positively correlated both with pre-strike PbB and with length of exposure to lead. It is likely that the dependence of apparent half-life on pre-strike PbB is primarily a reflection of interindividual differences in lead kinetics in these men. The direct dependence of apparent half-life on duration of lead exposure is consistent with published data from former lead workers and from human subjects experimentally exposed to lead.

Half-Life↗
PubMedDate not supplied

Children in Illinois with elevated blood lead levels, 1993-1998, and lead-related pediatric hospital admissions in Illinois, 1993-1997.

OBJECTIVE: This study uses screening and hospitalization data to describe the prevalence of childhood lead poisoning in Chicago and the rest of the state of Illinois. METHODS: The authors used aggregate data published by the Illinois Department of Public Health on blood lead testing of children ages 0-6 years and data on lead-related hospital admissions of children ages 0-6 years, drawn from an administrative dataset compiled as part of a state initiative. RESULTS: No clear time trends in the percentage of children with elevated blood lead levels (defined as >15 micrograms per deciliter [microg/dL] or >45 microg/dL) were evident in either Chicago or the rest of Illinois. The proportions of children with elevated blood lead levels in Chicago and in the rest of Illinois did not decline at the dramatic rate seen in the US as a whole during the 1990s. Over a five-year period, in-hospital charges of $7.7 million were generated for the care of lead-poisoned children ages 6-16 in Chicago alone. CONCLUSION: Surveillance data, analyzed at the appropriate geographic level, can be used to focus resources on high-risk areas and to evaluate prevention efforts.

Chicago↗
PubMed2003

Blood lead levels and risk factors for lead toxicity in children from schools and an urban slum in Delhi.

This cross-sectional study was conducted to estimate the mean blood lead levels (BLL) and prevalence of lead toxicity in a representative sample of schoolchildren and children residing in an urban slum. In addition, the association of potential environmental risk factors with elevated BLL was studied. Children aged 4-6 years were selected from schools of the South zone of Delhi (n = 125) and from an urban slum (n = 65). Risk factors were recorded using a pre-tested questionnaire and blood lead and zinc protoporphyrin (ZPP) levels were estimated. The mean BLL was 7.8 microg/dl (SD 3.9) and the proportion of children with blood lead > or = 10 microg/dl was 18.4 per cent. Distance of the residence or school from a main road appeared to be associated with higher blood lead concentrations, but these differences were not statistically significant. In our setting, vehicular pollution may be a major contributing factor in lead contamination of the environment.

Child↗
PubMed2006

Long-term follow-up of blood lead levels and haematological and biochemical parameters in heifers that survived an accidental lead poisoning episode.

Four of 10 heifers that survived an episode of lead poisoning caused by an old broken battery in the pasture were periodically monitored from days 14 to 205 after the episode, with the aim of (i) determining the time-course of lead clearance from blood; and (ii) assessing whether the exposed cattle showed changes in haematological parameters or serum markers of hepatic and renal function (e.g. serum creatinine level) that might be useful as indicators of subclinical toxicity. On the first sampling day, lead levels in blood varied between 0.478 and 0.758 mg/l. The half-life of lead in blood was rather variable, ranging from 68 to 266 days. Despite the high blood lead levels, no significant changes were detected in haematological parameters or hepatic/renal markers, all of which remained within normal ranges. In conclusion, these cattle that survived an episode of lead poisoning may constitute a risk for human consumers, but do not appear to have suffered severe health consequences themselves.

Animals↗