Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LEAD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1983

Effect of ingested lead on concentration of blood and tissue lead in rabbits.

The accumulation of lead (Pb) and erythrocyte protoporphyrin (EP) in blood was studied in 11 rabbits. The rabbits were given a daily dose of 50 mg Pb as lead nitrate, dissolved in 100 mL of drinking water. Blood samples were drawn once a week from the ear lobes and assayed for Pb and EP. The Pb concentration increased sharply during the administration of Pb while the EP concentration rose slowly. When Pb was withdrawn its concentration fell immediately, whereas the EP concentration started decreasing only after two weeks and the decrease was slower. At the end of the experiment the rabbits were sacrificed and the Pb content of a number of organs determined. The largest accumulation of Pb was in bone, followed by kidney, liver, lung, spleen, brain and heart. The concentration of Pb in brain and heart was much lower than in the excretory organs - spleen, kidney and liver.

Animals↗
PubMed1998

Site-specific lead distribution in scales of lead-administered carp (Cyprinus carpio) by non-destructive SR-XRF analysis.

By utilizing non-destructive synchrotron radiation-excited X-ray fluorescence (SR-XRF), we observed the distribution of lead (Pb) in both ontogenic and regenerating scales of lead-administrated carp, Cyprinus carpio. The fish in the Pb-administered group were fed pellets containing 1 mg/g of Pb at a rate of 1.5% body weight per day for 30 days. In the ontogenic scales, Pb was highly accumulated near the basal edge of the scale and the accumulated amount decreased toward the focus of the scale. On the other hand, in the regenerating scales, high accumulation was observed near the basal edge and the accumulated amount remained high toward the focus. The present results of Pb accumulation correspond well with the region which is calcifying in the ontogenic and regenerating scales, and indicate that the distributions of Pb show when and how long Pb was administered.

Animals↗
PubMed2002

Lead concentrations in fish and river sediments in the old lead belt of Missouri.

Although active mining activities in the Old Lead Belt of Missouri ceased in 1968, old tailings piles remain and continue to impact the lead (Pb) concentrations in sediments and fish in the Big River and Flat River Creek in Missouri. A 3-year study was conducted that examined the Pb concentrations in organic-rich sediments, fish fillets, and fish whole bodies at 13 sites in these two rivers. The results showed that the sediments had significantly elevated Pb concentrations near and beyond the tailings piles compared with control sites upstream from the mining activity. The results also showed the Pb concentration in sediments correlated well with Pb concentrations in suckers (r = 0.86, p < 0.0001) and small sunfish (r = 0.82, p < 0.0001). Annual average Pb concentrations in sucker fillets ranged up to 0.67 microg/g (wet weight basis) and exceeded the World Health Organization guidelines of 0.3 microg/g (wetweight basis) at many of the sample sites. Fillets of bass, which feed at a higher trophic level, had much lower Pb concentrations than either suckers or small sunfish, and no bass fillet samples exceeded the WHO guideline. Whole body Pb concentrations in small sunfish were also determined and correlated strongly (r = 0.92, p = 0.0004) with sediment concentrations before leveling at a maximum of approximately 20 microg/g (wet weight basis).

Animals↗
PubMed2004

Lead, zinc, copper, and cadmium in fish and sediments from the Big River and Flat River Creek of Missouri's Old Lead Belt.

The Old Lead Belt of Missouri was a major lead-producing region for over a century. Several large tailings piles and other industrial wastes remain behind, though mining operations in the region ceased in 1972. Samples of stream sediments and fish were collected from established sites on the Big River and Flat River Creek over a 3-year period from 1998 to 2000 to evaluate ongoing remediation efforts and determine the current impact of residual mining wastes. Benthic sediments and fish taken in the vicinity of inactive industrial sites were found to contain elevated concentrations of Pb, Zn, Cu, and Cd. Concentrations of Pb and Zn in fillets of suckers and sunfish, as well as in whole bodies of sunfish, correlate well with metal concentrations observed in surficial sediments. The results of analyses provide valuable quantitative information regarding specific sources, current levels of contamination, potential risk to public health, and will allow more accurate assessment of continuing remediation efforts.

Animals↗
PubMed2006

Quantitative determination of lead in mixtures of lead(II) halides using solid-state 207Pb NMR spectroscopy.

We demonstrate a multi-spectrum technique for facile, quantitative determination of lead in solid materials using solid-state (207)Pb NMR that avoids the major problem of uniform excitation across a wide spectral range; the method can be employed without chemical separation or other chemical manipulations and without any prior sample preparation, resulting in a non-destructive analysis, and producing results that are in agreement with gravimetric analyses of mixed samples of the lead halides.

Fluorides↗
PubMedDate not supplied

Relationships between blood lead concentration and aminolevulinic acid dehydratase in alcoholics and workers industrially exposed to lead.

Blood lead concentration (Pb-B), aminolevulinic acid dehydratase (ALAD), and gamma-GT were measured in 265 workers industrially exposed to lead and in 184 patients with liver disease resulting from alcohol consumption. The first group was divided according to alcohol use, i.e., nondrinkers, moderate drinkers, and heavy drinkers. The second group was divided according to the following criteria: hepatopatic without cirrhosis, hepatopatic with compensated cirrhosis, and hepatopatic with decompensated cirrhosis. Heavy drinkers who were industrially exposed had the highest Pb-B (40.4 +/- 14.6 micrograms/dl) and the lowest ALAD (22.2 +/- 9.1 U/L). The correlations between Pb-B and ALAD show no significant change with the increase of Pb-B. In the alcoholic group, 76 patients with alcoholic liver disease without cirrhosis had the highest Pb-B (40.3-9.1 micrograms/dl) and ALAD the lowest (18.6 +/- 7.7 U/L). The negative correlation between Pb-B and log ALAD disappeared completely in individuals with Pb-B that exceeded 50 micrograms/dl, independent from the seriousness of illness.

Adult↗
PubMed1983

Tissue distribution of lead in the neonatal rat exposed to multiple doses of lead acetate.

The tissue distribution of lead (Pb) was examined in the neonatal rat intragastrically administered lead acetate (50 mg/kg, containing 210Pb) beginning on d 6 postpartum and thereafter at 3-d intervals to d 18. A time-dependent pattern of uptake was observed in bone, kidney, liver, and brain, while stomach, lung, heart, and spleen had no accumulation of Pb. The highest concentration of Pb at d 21 was detected in bone, and the least amount was found in blood and brain. Body weight was not significantly affected by the level of Pb exposure employed.

Animals↗
PubMed2005

Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers.

OBJECTIVE: The level of lead (Pb) exposure necessary to induce intellectual impairment has not been firmly established. Some studies using conventional language-based intelligence tests have reported that pediatric blood lead (PbB) levels lower than 10 microg/dL (0.483 micromol/L) are associated with neurocognitive impairment. However, these tests may introduce cultural biases in the assessment of intellectual functioning. The objective of this study was to assess the effects of PbB concentration on nonverbal intelligence in Andean children with chronic environmental Pb exposure using a nonlanguage-based test of cognitive functioning. METHODS: Using Raven Colored Progressive Matrices (RCPM) as a measure of nonverbal intelligence, this study investigated the effects of Pb exposure (biomarker: PbB levels) on intellectual functioning in 188 chronically Pb-exposed children (age range: 5.33-11.67 years) of Ecuadorian Andean Pb-glazing workers. RESULTS: The mean PbB level of the 188 children was 29.3 microg/dL (range: 3.5-94.3 microg/dL). Forty-seven children had PbB levels <10 microg/dL (Centers for Disease Control and Prevention [CDC] I classification), of which 30 had abnormal (ie, < or =25th percentile) RCPM standard scores. Of the 141 children with PbB levels > or =10 microg/dL, 97 had abnormal RCPM scores. A regression analysis revealed a statistically significant negative association (r = -0.331, P < 0.0001) between PbB level and RCPM standard score. Conversion of RCPM standard scores to estimated IQ scores showed an approximate two-point decrease in IQ for each 10-microg/dL increment in PbB level from 10 to >70 microg/dL. CONCLUSIONS: Performance on a test of nonverbal intelligence was inversely associated with chronic Pb exposure in Andean children with PbB levels below and above the CDC risk management level of 10 microg/dL, with the decline in test scores suggesting a dose-response relationship.

Adult↗
PubMed1994

Renal function and hyperfiltration capacity in lead smelter workers with high bone lead.

OBJECTIVE: The study was undertaken to assess whether the changes in urinary excretion of eicosanoids (a decrease of 6-keto-PGF1 alpha and PGF2 and an increase of thromboxane) previously found in lead (Pb) exposed workers may decrease the renal haemodynamic response to an acute oral protein load. METHODS: The renal haemodynamic response was estimated by determining the capacity of the kidney to increase the glomerular filtration rate (in terms of creatinine clearance) after an acute consumption of cooked red meat (400 g). A cross sectional study was carried out in 76 male Pb workers (age range 30 to 60 years) and 68 controls matched for age, sex, socioeconomic state, general environment (residence), and workshift characteristics. RESULTS: The Pb workers had been exposed to lead on average for 18 (range 6-36) years and showed a threefold higher body burden of Pb than the controls as estimated by in vivo measurements of tibial Pb concentration (Pb-T) (geometric mean 66 v 21 micrograms Pb/g bone mineral). The geometric mean concentrations of Pb in blood (Pb-B) and Pb in urine (Pb-U) were also significantly higher in the Pb group (Pb-B: 430 v 141 micrograms Pb/l; Pb-U: 40 v 7.5 micrograms Pb/g creatinine). These conditions of chronic exposure to Pb did not entail any significant changes in the concentration of blood borne and urinary markers of nephrotoxicity, such as urinary low and high molecular weight plasma derived proteins (beta 2-microglobulin, retinol binding protein, albumin, transferrin), urinary activities of N-acetyl-beta-D-glucosaminidase and kallikrein, and serum concentrations of creatinine, beta 2-microglobulin, urea, and uric acid. All participants also had normal baseline creatinine clearances (> 80 ml/min/1.73 m2) amounting on average to 115.5 in the controls v 121.3 ml/min/1.73 m2 in the Pb group. Both control and Pb exposed workers showed a significant increment in creatinine clearance (on average 15%) after oral protein load suggesting that the previously found changes in secretion of urinary eicosanoids apparently has no deleterious effect on renal haemodynamics in the examined Pb workers. CONCLUSIONS: The finding that both baseline and stimulated creatinine clearance rates were not only significantly higher in the Pb workers but also positively correlated with Pb-T, suggests that moderate exposure to Pb may be associated with a slight hyperfiltration state, which has been found to attenuate the age related decline in baseline creatinine clearance by a factor of two. Although the relevance of this effect for the worker's health is unknown, it can be concluded that adverse renal changes are unlikely to occur in most adult male Pb workers when their blood Pb concentration is regularly kept below 700 micrograms Pb/l. One should, however, be cautious in extra-polating this conclusion to the general population because of pre-employment screening of the Pb workers for the absence of renal risk factors.

Adult↗
PubMedDate not supplied

Gender differences in blood lead and hemoglobin levels in Andean adults with chronic lead exposure.

A field study of the prevalence of lead (Pb) intoxication was conducted in 158 adults (67 men and 91 women) living at 2,500-2,800 meters in Ecuadorian Andean villages with high Pb contamination from local small-scale Pb-glazing cottage industries. Venous blood samples showed mean blood lead (PbB) levels of 34.5 microg/dL (SD 22.2) for men and 27.0 microg/dL (SD 18.4) for women; this difference was significant (t-test, p = 0.022; Mann-Whitney U, p = 0.044). An ANOVA showed no significant main effect for gender (F = 0.118, p = 0.782) or age (F = 2.479, p = 0.117), and no significant gender-by-age interaction (F = 0.273, p = 0.602). In the Pb-glazing study group, 39% of the men had PbB levels > or = 40 microg/dL, while 41% of the women had PbB levels > or = 30 microg/dL (the WHO health-based biological limits). A reference group of 39 adults (24 men and 15 women) had a mean PbB level of 5.9 microg/dL (SD 2.8; range: 1.8-16.8), significantly different from that of the 158 subjects in the study group (t-test, p < 0.0001). The difference in mean PbB levels of men (6.8 microg/dL) and women (4.7 microg/dL) in the reference group was significant (t-test, p = 0.026; Mann-Whitney U, p = 0.019). The mean altitude-corrected hemoglobin levels in the study group were lower than normal, 11.3 g/dL for men and 10.9 g/dL for women.

Adolescent↗
PubMed2005

Seasonality and children's blood lead levels: developing a predictive model using climatic variables and blood lead data from Indianapolis, Indiana, Syracuse, New York, and New Orleans, Louisiana (USA).

On a community basis, urban soil contains a potentially large reservoir of accumulated lead. This study was undertaken to explore the temporal relationship between pediatric blood lead (BPb), weather, soil moisture, and dust in Indianapolis, Indiana; Syracuse, New York; and New Orleans, Louisiana. The Indianapolis, Syracuse, and New Orleans pediatric BPb data were obtained from databases of 15,969, 14,467, and 2,295 screenings, respectively, collected between December 1999 and November 2002, January 1994 and March 1998, and January 1998 and May 2003, respectively. These average monthly child BPb levels were regressed against several independent variables: average monthly soil moisture, particulate matter < 10 microm in diameter (PM10), wind speed, and temperature. Of temporal variation in urban children's BPb, 87% in Indianapolis (R2 = 0.87, p = 0.0004), 61% in Syracuse (R2 = 0.61, p = 0.0012), and 59% in New Orleans (R2 = 0.59, p = 0.0000078) are explained by these variables. A conceptual model of urban Pb poisoning is suggested: When temperature is high and evapotranspiration maximized, soil moisture decreases and soil dust is deposited. Under these combined weather conditions, Pb-enriched PM10 dust disperses in the urban environment and causes elevated Pb dust loading. Thus, seasonal variation of children's Pb exposure is probably caused by inhalation and ingestion of Pb brought about by the effect of weather on soils and the resulting fluctuation in Pb loading.

Child, Preschool↗
PubMed1996

Indices of lead-exposure in blood and urine of lead-exposed workers and concentrations of major and trace elements and activities of SOD, GSH-Px and catalase in their blood.

Seventy male factory workers were studied. The lead concentrations in their blood (Pb-B) were 16.55 +/- 11.53 micrograms/100 ml (range 1.5 to 50.2 micrograms/100 ml). The subjects were divided into three groups according to Pb-B (in microgram/100 ml): group A, Pb-B < or = 10 (n = 22); group B, 10 < Pb-B < or = 20 (n = 30); group C, Pb-B > 20 (n = 18). The mean +/- S.D. in each group was 5.57 +/- 2.53, 15.02 +/- 2.75, and 32.52 +/- 9.49 micrograms/100 ml, respectively. Pb in plasma was 0.011 +/- 0.010, 0.017 +/- 0.033, and 0.021 +/- 0.021 microgram/liter, and Pb in the RBC was 0.281 +/- 0.246, 0.701 +/- 0.325, and 1.626 +/- 0.861 micrograms/g Hb, respectively. In addition to Pb concentration, the concentrations of 34 elements in the plasma or in the RBC were determined. Se concentrations in RBC in each group were 0.618 +/- 0.139, 0.670 +/- 0.207, and 0.728 +/- 0.200 microgram/g Hb, and the mean values were significantly different between groups A and C (p < 0.05). For Se concentration in plasma, the mean +/- S.D. in each group was 0.132 +/- 0.035, 0.130 +/- 0.031, and 0.126 +/- 0.021 microgram/ml, respectively, and there was no significant difference between groups. On the other hand, when the activities of total SOD, Mn-SOD, Cu, Zn-SOD, and catalase in the plasma and the activities of GSH-Px both in the plasma and in the RBC were assayed, some differences were found. The activities in GSH-Px in RBC were 17.19 +/- 5.03, 17.59 +/- 3.95, and 15.25 +/- 3.18 mumol/g Hb/min, and those in plasma were 0.069 +/- 0.032, 0.081 +/- 0.023, and 0.080 +/- 0.028 mumol/ml/min. In group C, GSH-Px activity was lower in the RBC and higher in the plasma than those in group A, and it was observed that the Se concentration was higher in RBC, and that there was no remarkable change in the plasma. Catalase activity in group C was 3.58 +/- 0.81 mgH2O2/ml/30 min, which was significantly higher than that in group A (2.81 +/- 0.90 mgH2O2/ml/30 min). Further investigation is necessary in order to explain the above results. The regular indices used for evaluating lead exposure, showed significant correlations with Pb-B: r = -0.786 vs delta-Aminolevulinic acid (ALA) dehydratase activity in blood, r = 0.927 vs. inhibition rate, and r = 0.339 vs. ALA in urine.

Aminolevulinic Acid↗
PubMed2000

Blood lead level to induce significant increase in urinary delta-aminolevulinic acid level among lead-exposed workers: a statistical approach.

The present study was initiated to examine the quantitative relationship between blood lead (Pb-B) and urinary delta-aminolevulinic acid (ALA-U) among Pb-exposed workers, and to find a threshold Pb-B level to induce an increase in ALA-U. For this purpose, pairs of venous blood and spot urine samples were collected from 8,274 men and 5,856 women (14,130 workers in total) who were occupationally exposed to inorganic lead. The blood and urine samples were analyzed for Pb-B and ALA-U by atomic absorption spectrometry and colorimetry, respectively, and the correlation between pairs of measures were subjected to statistical analysis. The assumption of the 3rd degree regression for correlation gave a substantially greater correlation coefficient (0.645 for men and 0.619 for women) than 1st or 2nd degree regression, whereas only very small improvement in the coefficient was achieved with 4th to 6th degree ones. Logarithmic conversion of the parameters was not effective in improving the correlation. The assumption of the 3rd degree regression followed by calculation of the local minimum gave 22, 29 and 23 micrograms/100 ml Pb-B for men, women, and men + women, respectively, as the threshold Pb-B to induce ALA-U increase. Pb-B to elevate ALA-U to the 95% upper normal limit (8 mg/l, common to men and women) was 62, 50 and 58 micrograms/100 ml for men, women and men + women, respectively. The validity of the 3rd degree regression assumption as a tool to calculate a threshold from experimental or epidemiological data is discussed.

Adult↗
PubMed2005

Lead accumulation by tall fescue (Festuca arundinacea Schreb.) grown on a lead-contaminated soil.

Phytoextraction is gaining acceptance as a cost-effective and environmentally friendly phytoremediation strategy for reducing toxic metal levels from contaminated soils. Cognizant of the potential of this phytoremediation technique as an alternative to expensive engineering-based remediation technologies, experiments were conducted to evaluate the suitability of some plants as phytoextraction species. From one of our preliminary studies, we found that tall fescue (Festuca arundinacea Schreb. cv. Spirit) can tolerate and accumulate significant amounts of lead (Pb) in its shoots when grown in Pb-amended sand. To further evaluate the suitability of tall fescue as one of the potential crop rotation species for phytoextraction, a study was conducted to determine whether the addition of ethylenediaminetetraacetic acid (EDTA) alone or in combination with acetic acid can further enhance the shoot uptake of Pb. Seeds were planted in 3.8 L plastic pots containing top soil, peat, and sand (4:2:1, v:v:v) spiked with various levels (0,1000, 2000 mg Pb/kg dry soil) of lead. At six weeks after planting, aqueous solutions (0, 5 mmol/kg dry soil) of EDTA and acetic acid (5 mmol/kg dry soil) were applied to the root zone, and all plants were harvested a week later. Results revealed that tall fescue was relatively tolerant to moderate levels of Pb as shown by non-significant differences in root and shoot biomass among treatments. An exception to this trend however, was the slight reduction in root and shoot biomass of plants exposed to the highest Pb level in combination with the two chelates. Root Pb concentration increased with increasing level of soil-applied Pb. Further increases in root Pb concentrations were attributed to chelate amendments. Translocation index, which is a measure of the partitioning of the metal to the shoots, was significantly enhanced with chelate addition especially when both EDTA and acetic acid were used. Chelate-induced increases in translocation indices correspondingly led to higher shoot Pb concentrations.

Biodegradation, Environmental↗
PubMed2005

EDTA-assisted phytoextraction of lead from lead-contaminated soils by Echinochloa crusgalli var. frumentacea.

The herbaceous plant Echinochloa crusgalli var. frumentacea is highly resistant to a wide range of heavy metal concentrations. In this study we tested the phytoextraction capacity of E. crusgalli var. frumentacea. Specifically, we compared the effect of EDTA on lead (Pb) accumulation in two groups of plants: those sown in lead contaminated soil and those transplanted to the contaminated soil as seedlings. The result of the time development of the Pb concentrations in the plants in the seedling and seed groups shows that for the seedling group, the effect of adding EDTA to the Pb-contaminated soil was even more pronounced in the shoots than the roots, which showed Pb concentrations 32-fold higher. Compared to the seedling group, the Pb concentrations in the roots of plants in the seed group were approximately 5 times higher in controls and 2 to 10 times higher in the presence of EDTA. Collectively, these results might be considered that EDTA elevates the bioavailability of Pb in soil and this native species is particularly suited to use in Pb phytoextraction.

Biodegradation, Environmental↗
PubMed1991

Observational study of erythrocyte protoporphyrin screening test for detecting low lead exposure in children: impact of lowering the blood lead action threshold.

We examined a retrospective sample of 1800 children on whom both erythrocyte protoporphyrin (EP) and blood lead (BPb) measurements were taken. The primary objective was to ascertain whether EP is a cost-effective screening test for low but increased BPb concentrations and to establish the optimal thresholds. The data did not provide evidence of an EP threshold at low BPb concentrations; however, the data did show a significant age effect. A subset of 500 children for whom both EP and hematocrit data were available showed no correlation between those variables. Age-specific operating characteristic curves, total error, and cost analyses are presented. The latter sets bounds on the relative cost of EP testing, above which only BPb determination should be performed. The implications of these findings are discussed in light of impending changes in U.S. federal guidelines for preventing lead poisoning in young children.

Aging↗
PubMed1977

Lead-contaminated health food. Association with lead poisoning and leukemia.

A doctor prescribed a dietary supplement prepared from powdered animal bone for a young woman with dysmenorrhea. Severe lead poisoning developed while she was taking the powder, which was shown to be contaminated with lead. The diagnosis eluded more than 20 physicians and was finally made by the patient herself. The Food and Drug Administration, informed of the contamination, declined to take action, stating that a food supplement is neither a food nor a drug and, besides, there are no maximal limits for heavy-metal contamination of foods and drugs.

Acute Disease↗