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PubMedDate not supplied

The Yugoslavia Prospective Lead Study: contributions of prenatal and postnatal lead exposure to early intelligence.

To investigate associations between the timing of lead (Pb) exposure on early intelligence, we examined the results of psychometric evaluations at ages 3, 4, 5, and 7 years, from 442 children whose mothers were recruited during pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia. We compared the relative contribution of prenatal blood lead (BPb) with that of relative increases in BPb in either the early (0-2 years) or the later (from 2 years on) postnatal period to child intelligence measured longitudinally at ages 3 and 4 (McCarthy GCI), 5 (Wechsler Preschool and Primary Scale of Intelligence-Revised, WPPSI-R IQ), and 7 (Wechsler Intelligence Scale for Children-version III, WISC-III IQ), controlling for: Home Observation for Measurement of the Environment (HOME) quality; maternal age, intelligence, education, and ethnicity; and birthweight and gender. Elevations in both prenatal and postnatal BPb were associated with small decrements in young children's intelligence.

Analysis of Variance↗
PubMed2005

Miniaturized lead sensor based on lead-specific DNAzyme in a nanocapillary interconnected microfluidic device.

A miniaturized lead sensor has been developed by combining a lead-specific DNAzyme with a microfabricated device containing a network of microfluidic channels that are fluidically coupled via a nanocapillary array interconnect. A DNAzyme construct, selective for cleavage in the presence of Pb2+ and derivatized with fluorophore (quencher) at the 5' (3') end of the substrate and enzyme strands, respectively, forms a molecular beacon that is used as the recognition element. The nanocapillary array membrane interconnect is used to manipulate fluid flows and deliver the small-volume sample to the beacon in a spatially confined detection window where the DNAzyme is interrogated using laser-induced fluorescence detection. A transformed log plot of the fluorescent signal exhibits a linear response (r2 = 0.982) over a Pb2+ concentration range of 0.1 - 100 microM, and a detection limit of 11 nM. The sensor has been applied to the determination of Pb2+ in an electroplating sludge reference material, the result agreeing with the certified value within 4.9%. Quantitative measurement of Pb2+ in this complex sample demonstrates the selectivity of this sensor scheme and points favorably to the application of such technologies to analysis of environmental samples. The unique combination of a DNAzyme with a microfluidic-nanofluidic hybrid device makes it possible to change the DNAzyme to select for other compounds of interest, and to incorporate multiple sensing systems within a single device for greater flexibility. This work represents the initial steps toward creation of a robust field sensor for lead in groundwater or drinking water.

Biosensing Techniques↗
PubMedDate not supplied

Interactions of lead, calcium, vitamin D, and nutrition in lead-burdened children.

This study was undertaken to evaluate relationships between blood or serum levels of lead (Pb), calcium, and 25-hydroxyvitamin D (25-OHD), within the framework of a nutritional survey of lead-burdened children. The results demonstrate that: regardless of blood Pb concentration and season of the year, serum 25-OHD concentration reflects vitamin D intake; high blood Pb (greater than or equal to 60 microgram/dl) was associated with decreased levels of 25-OHD (18+/--1 ng/ml vs. 32+/- in controls, P less than .001); concentrations Pb and calcium were inversely correlated in control and lead-burdened children; and children in the high blood Pb group (greater than or equal to 60 microgram/dl) had lower mean daily intakes of both calcium (610 +/- 20 mg vs. 770 +/- 20 in controls, P less than .001) and vitamin D (210 +/- 17 IU vs. 325 +/- 20 in controls, P less than .001). These data indicate that, in Pb-burdened children, multiple factors modify the absorption and toxicity of Pb, and relative vitamin D deficiency, not excess, is associated with high blood Pb levels. Assessment of nutrition, calcium metabolism, and vitamin D status is recommended in evaluating children known to have undue absorption of Pb.

Alkaline Phosphatase↗
PubMedDate not supplied

Elevated blood lead in a population near a lead smelter in Kosovo, Yugoslavia.

A survey of residents of a community surrounding a lead smelter has revealed an alarming incidence of elevated blood lead and erythrocyte protoporphyrin concentrations. In particular, children who were less than 3 yr of age were severely affected. Of those children tested in December, 1980, 35% had blood lead concentrations between 50-69 microgram/dl, while an additional 12% had concentrations greater than or equal to 70 microgram/dl, and are, therefore, at risk for severe neurological sequelae.

Adolescent↗
PubMedDate not supplied

Air lead exposures and blood lead levels within a large automobile manufacturing workforce, 1980-1985.

Recent (1980-1985) trends in air lead (PbA) exposures and blood lead (PbB) levels experienced by approximately 10,000 workers employed in various stages of the automobile manufacturing process (i.e., auto assembly, lead-acid battery manufacture, foundry work, and "other" manufacturing-related operations) are described. Between 1980-1985, the mean PbB levels of assembly, battery, foundry, and "other" workers decreased by 28, 24, 3, and 27%, respectively, to 16.6, 23.6, 15.9, and 11.8 micrograms Pb/dl. Workers in the following job categories experienced the highest annual mean PbB levels: paste machine operators (battery plants), solder-grinders (assembly plants), and crane operators (foundries). During the same period, median 8-h Time Weighted Average PbA exposures (micrograms Pb/m3) in assembly plants, battery plants, and foundries decreased by 10, 12, and 20%, respectively, to 8.1, 13.6, and 10.9 micrograms/m3.

Adult↗
PubMedDate not supplied

Lead's legacy? Early and late mortality of 454 lead-poisoned children.

A series of 454 pediatric hospital patients who were diagnosed with lead poisoning between 1923 and 1966 were traced through 1991 to examine possible mortality effects. Numbers of observed deaths were compared with those expected, based on the rates of the U.S. population. Eighty-six deaths were observed (O/E = 1.7, 95% confidence interval (95% CI) = 1.4-2.2), of which 17 were attributed to lead poisoning. Mortality from all cardiovascular disease was elevated (O/E = 2.1, 95% CI = 1.3-3.2), and cerebrovascular deaths were particularly common among women (O/E = 5.5, 95% CI = 1.1-15.9). Among men, 2 deaths resulted from pancreatic cancer (O/E = 10.2, 95% CI = 1.1-36.2), and 2 deaths resulted from non-Hodgkin's lymphoma (O/E = 13.0, 95% CI = 1.5-46.9). Chronic nephritis was not a significant cause of death. Despite limitations in the data, the pattern of mortality suggests that effects of lead poisoning in childhood may persist throughout life and may be experienced differently by men and women.

Cause of Death↗
PubMed1981

Blood lead and zinc protoporphyrin in lead industry workers.

A retrospective study was performed by evaluating the time course changes in blood lead and zinc protoporphyrin concentrations in 240 industrial lead workers. The data indicate that there is a considerable difference in rate of change and plateau state for each of the two parameters. The difference in time course in these parameters indicates that both should be monitored in workers in order to estimate the accumulation of lead and the metabolic response to the body burden.

Body Burden↗
PubMed1991

First-year changes in blood lead and zinc protoporphyrin levels within two groups of occupational lead workers.

Quarterly changes in blood lead (PbB) and zinc protoporphyrin (ZPP) levels experienced by 30 male lead-acid storage battery workers and 24 auto assembly workers during their initial year of occupational lead exposure are described. The greatest absolute and percentage increases above baseline PbB levels occurred during the first 3 months of continuous exposure when battery and assembly workers' average PbB levels increased by 99% and 134%, respectively. Peak average PbB levels were reached during the second quarter of exposure for battery workers (27.3 micrograms/dL) and during the third quarter for assembly workers (34.3 micrograms/dL). Mean ZPP levels increased steadily through the first 3 quarters of exposure for both groups of workers before declining slightly during the final 3 months. Third-quarter average ZPP levels were 46.6 micrograms/dL for battery workers and 59.4 micrograms/dL for assembly workers. In general, for the assembly workers, the slopes of quarterly dose (PbB)-effect (loge ZPP) regressions increased with increasing exposure duration (up to 0.044 by the third quarter of exposure) and were significant (p less than 0.0001). Similar calculations for the battery workers were not statistically significant (p greater than 0.05) and showed no exposure-related trends. Probit-based dose (PbB)-response (ZPP level greater than two standard deviations above the baseline ZPP) analyses of the assembly worker data resulted in a 30.0 micrograms/dL ED50 estimate (PbB concentration at which 50% of a similarly exposed population would be expected to develop an "elevated" ZPP level).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Lead uptake and the effects of EDTA on lead-tissue concentrations in the desert species mesquite (Prosopis spp.).

Experimental results have shown that the desert plant species mesquite (Prosopis spp.) is capable of accumulating high levels of lead in the roots, translocating it to the aerial portion of the plant. One-week-old mesquite seedlings were treated for 7 d in a hydroponic culture using a modified Hoagland solution. Six treatments were used; three treatments contained only Pb [as Pb(NO3)2] at 25-, 50-, and 75-mg L(-1) levels and three treatments contained the same levels of Pb, but with equimolar concentrations of disodium ethylenediamine tetraacetic acid (EDTA). Our results showed that the plants exposed to 25-, 50-, and 75-mg Pb L(-1) treatments without EDTA concentrated in stems 524, 3726, and 1417 mg kg(-1), respectively. However, the plants treated with Pb-EDTA concentrated in stems 480-, 607-, and 1247-mg Pb kg(-1) for the 25-, 50-, and 75-mg Pb L(-1) treatments, respectively. Results for the roots followed a similar trend; without EDTA the Pb levels ranged from 16,055, 89,935, and 63,396 for the 25-, 50-, and 75-mg Pb L(-1) treatments, respectively, and with EDTA these levels were 9,562, 49,902, and 39,181 mg kg(-1) for the three treatments. However, the addition of EDTA increased lead movement to the leaves. The levels of Pb without EDTA were 20, 35, and 51 mg kg(-1) for the 25-, 50-, and 75-mg Pb L(-1) levels, respectively. Treatments with EDTA showed uptake levels of 105, 124, and 313 for the 25-, 50-, and 75-mg Pb L(-1) treatments. Further, the percent Pb in dry leaf tissues for all EDTA treatments were greater than 0.1%. However, only the 25-mg Pb L(-1) treatment was greater than 0.1%, compared to 0.04 and 0.08% for the 50- and 75-mg Pb L(-1) treatments, respectively. Preliminary transmission and scanning electron microscopy corroborate the presence of lead.

Biodegradation, Environmental↗
PubMed2006

Lead nephropathy: early leads from descriptive studies.

Chronic lead exposure is recognized as a potential cause of hyperuricaemia, kidney damage and hypertension. The fascinating story of lead poisoning and nephrotoxicity illustrates the utility of descriptive studies in the early elucidation of a new disease entity. The pursuit towards understanding lead nephropathy is presented as a successful illustration of human occupational and public health.

History, 19th Century↗
PubMed1972

Air lead: relation to lead in blood of black school children deficient in glucose-6-phosphate dehydrogenase.

Forty-four black children at two elementary schools within 0.7 mile of a battery plant had significantly higher (P < .001) concentrations of lead in their bloods (34.1 +/- 9.7, micrograms per 100 milliliters, mean +/- standard deviation) than 122 students (26.3 +/- 7.1) at seven schools 1 to 3 miles distant; 5 months later there was a comparable difference between red cell lead values (54.1 +/- 18.5 versus 37.4 +/- 12.6). Among the blacks, those deficient in glucose-6-phosphate dehydro-genase had a higher (P < .005) concentration of lead in the blood after correction for anemia (32.9 +/- 9.7) than the nondeficient (25.7 +/- 8.8), and a higher concentration in the red cells (47.3 +/- 14.7 as compared to 35.6 +/- 15.8, P < .001); the enzyme effect was independent of geographic location.

Air Pollution↗
PubMed1988

Blood lead, ethnic origin, and lead exposure.

A survey of blood lead concentrations is reported in a group of 199 young Walsall children (3-6 years of age). The geometric mean blood lead concentration was 0.47 mumol/l (range 0.2-1.6 mumol/l). There were no significant differences in blood lead concentrations between groups of children with different ages, sex, ethnic origin, or environment.

Child↗
PubMed2005

Blood lead and erythrocyte protoporphyrin levels in association with smoking and personal hygienic behaviour among lead exposed workers.

AIMS: To investigate the effects of smoking and personal hygienic behaviour on blood lead (BPb) and free erythrocyte protoporphyrin levels (FEP) in lead exposed workers. METHODS: Subjects were 105 lead exposed male workers in a battery recycling plant during the years 2000-03. BPb and FEP were measured as part of the ongoing occupational surveillance. Each worker completed a questionnaire for assessment of smoking and four measures of personal hygienic behaviour (glove and mask use, hand and face washing before meals during working hours). RESULTS: Statistically significant decreases in mean BPb and FEP occurred during the three years. The proportion of BPb reduction in the non-smoking workers was significantly higher (mean 24.3%) than in the smoking workers (15.3%). When the workers were classified into three groups (excellent, good, and poor) based on the four personal hygienic behavioural indicators, the greatest decreases of BPb and FEP were observed in the non-smoking workers of the excellent group. CONCLUSIONS: The consistent use of protection devices and cleanliness at work appeared to contribute to the lowering of BPb and FEP. Cessation of smoking in the workplace was also of importance.

Adult↗
PubMed2005

Reduction of magnetic resonance imaging-related heating in deep brain stimulation leads using a lead management device.

OBJECTIVE: To evaluate the ability of a lead management device to reduce magnetic resonance imaging (MRI)-related heating of deep brain stimulation (DBS) leads and thereby to decrease the risks of exposing patients with these implants to MRI procedures. METHODS: Experiments were performed using the Activa series (Medtronic, Inc., Minneapolis, MN) DBS systems in an in vitro, gelled-saline head and torso phantom. Temperature change was recorded using fluoroptic thermometry during MRI performed using a transmit-and-receive radiofrequency body coil at 1.5 T and a transmit-and-receive radiofrequency head coil at 3 T. A cranial model placed in the phantom was used to test a custom-designed burr hole device that permitted the placement of small-diameter, concentric loops around the burr hole at the DBS lead as it exited the cranium. RESULTS: A total of 41 scans were performed, with absolute temperature changes ranging from 0.8 to 10.3 degrees C. Depending on the MRI system tested and the side of the phantom on which the hardware was placed, loop placement resulted in reductions in temperature rise of 41 to 74%. The effect was linearly related to the number of loops formed (P < 0.01) over the range tested (0-2.75 loops). CONCLUSION: Small, concentric loops placed around the burr hole seem to reduce MRI-related heating for these implants. Although the mechanism is still not fully understood, a device such as that used in the present study could permit a wider range of clinical scanning sequences to be used at 1.5 and 3 T in patients with DBS implants, in addition to increasing the margin of safety for the patient.

Deep Brain Stimulation↗
PubMed1998

Studies on lead-binding protein and interaction between lead and selenium in the human erythrocytes.

To clarify the function of Pb-binding protein and the interaction between lead and selenium in human erythrocytes, the following experiments were performed. (a) blood from a man who has not been exposed to lead occupationally, (b) blood from lead-exposed workers and (c) blood from control subjects working in the same plant were used. (a) was incubated with Pb and/or Se. Hemolysates of rinsed erythrocytes were applied onto a Bio-gel A 1.5 m column and eluted by 40 mM Tris-HCl buffer (pH 7.0). As the results, (1) Pb in erythrocytes was found in ALAD fraction. When Pb was added in vitro at 1.25 microM of final concentration, Pb content of ALAD fraction increased and the other Pb-containing fraction appeared at the position of a smaller molecular size than that of Hb fraction. When Pb dose added was increased to 2.5 or 10 microM, Pb contents in the newly appeared fraction was larger than that in ALAD fraction. The affinity of Pb with the protein in the new fraction was weak, and Pb was released from the protein by ultrafiltration. (2) There were main and sub-peaks containing Pb in erythrocytes from Pb-workers; the former was ALAD fraction and the others were smaller molecules than ALAD. The peak of Pb observed with the blood from a worker who has worked at the same plant for more than 20 years (chronic exposure) corresponded with the new peak which appeared in vitro Pb exposure. (3) As to the interaction between Pb and Se, there was no effect of Se added in vitro on the position of Pb-containing fraction and on Pb amounts in the chromatographic profile. When Se was incubated with blood, however, coexistence of Pb made Se concentration in erythrocytes high compared with the case of Se alone.

Carrier Proteins↗
PubMed1985

Metabolism of tetraorganolead compounds by rat-liver microsomal mono-oxygenase. III. Enzymic dealkylation of tetramethyl lead compared with tetraethyl lead.

The enzymic transformation of tetramethyl lead (PbMe4) to the trimethyl lead cation is very rapid with sp. activities of 40-50 nmol/min per mg protein. The reaction has an apparent Km of 1.28 X 10(-5) M. PbMe4 binds to cytochrome P-450 with a type 1 difference spectrum, Ks is 6.65 X 10(-6) M. Comparison of the data with results previously obtained for lead tetraethyl (PbEt4) shows that the 20 times higher metabolic rates observed with PbMe4 are related to an intrinsic higher O2 activation as well as to a more effective O2 utilization by that substrate.

Animals↗
PubMed1987

Lead exposure during demolition of a steel structure coated with lead-based paints. II. Reversible changes in the conduction velocity of the motor nerves in transiently exposed workers.

In a group of workers exposed to high levels of lead during five months nerve conduction velocity parameters were evaluated at the termination of exposure, and also three and fifteen months later. At the termination of exposure the mean blood lead level was 4.0 mumol/l, and motor conduction velocities in the median and the ulnar nerves were slower and the distal latencies in the median nerve were longer compared to the values measured 15 months later. Sensory conduction velocities, measured distally in the same nerves, were not depressed compared to the values measured three or fifteen months later. It was tentatively concluded that the effect of lead on the conduction velocity of the motor nerves has an initial reversible phase, dependent on the duration of exposure.

Adult↗