The effects of sodium citrate in lead poisoning and lead absorption: lead poisoning.
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Citrates↗
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The effects of sodium citrate in lead poisoning and lead absorption: Lead absorption.
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Citrates↗
[Paralysis of the arms due to lead poisoning occurring a year after exposure to lead; fraudulent prolongation of the poisoning or excessive activity of lead due to therapy].
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Arm↗
[Case of optic atrophy due to lead with late manifestations; importance of the mobilization of lead in the clinical diagnosis of lead poisoning].
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Humans↗
Relationship of blood lead levels to personal hygiene habits in lead battery workers: Taiwan, 1991-1997.
BACKGROUND: The blood lead concentrations of workers in lead battery factories are more than 4 times higher than those of the general population in Taiwan. Therefore, efforts are needed to reduce lead exposure in this high-risk population. A health promotion program on personal habits that reduce lead exposure has been carried out in a lead battery factory since 1991. This study investigated the longitudinal relationship of workers' blood lead concentrations and personal hygiene habits from 1991 through 1997. METHODS: In each of the 7 years of the study, occupational physicians questioned workers regarding nine personal hygiene items, personal information, and medical history before their annual health examination. The relationship between blood lead concentrations and personal hygiene habits was analyzed by longitudinal multiple regression in a mixed effect model with adjustment for potential confounders. In addition, the risk ratio of a blood lead concentration exceeding 40 micrograms/dL in men and 30 micrograms/dL in women (the action levels set by the Department of Health, Taiwan) was estimated by generalized estimating equations. RESULTS: Blood lead levels decreased significantly in the first 5 years of the study. The personal habits most closely related to blood lead concentrations were smoking at work sites (estimated coefficient = 3.13, P < 0.001), and eating at work sites (estimated coefficient = 1.38, P = 0.069). The risk ratio for workers with both these habits exceeding the action level of blood lead was 2.93 (95% CI 1.27-6.77). Difference in job titles, however, accounted for a major portion of the variance in blood lead. For example, working in "pasting" and "plate-cutting" was associated with blood lead elevations > 20 micrograms/dL in comparison to the "low- or no-exposure jobs." CONCLUSIONS: Health promotion programs can decrease exposure of lead workers; reducing the practices of smoking and eating at work sites should be the core of such programs. However, a major reduction in lead exposure for some jobs (e.g., "pasting" and "plate cutting") in lead battery factories in Taiwan is unlikely to occur without major engineering changes.
Feeding Behavior↗
Use of sequentially administered stable lead isotopes to investigate changes in blood lead during pregnancy in a nonhuman primate (Macaca fascicularis).
The effects of pregnancy on the flux of lead from maternal bone were investigated in five females from a unique colony of cynomolgus monkeys (Macaca fascicularis) which had been dosed orally with lead (approximately 1100-1300 microg Pb/kg body wt) throughout their lives (about 14 years). Through the use of stable lead isotopes 204Pb, 206Pb, and 207Pb, it was possible to differentiate between the lead contributed to blood lead from the skeleton and the lead contributed from the current oral dose. Blood samples and bone biopsy samples taken before, during, and after pregnancy were analyzed for lead (total and stable isotope ratios) by thermal ionization mass spectrometry. Through the use of end-member unmixing equations, the contribution to blood of lead from maternal bone during pregnancy was estimated and compared to the contribution of lead from maternal bone before pregnancy. A 29 to 56% decrease in bone lead mobilization in the first trimester was followed by an increase in the second and third trimesters, up to 44% over baseline levels. In one monkey, the third-trimester increase did not reach baseline levels. In a single low-lead monkey, a similar decrease in the first trimester was followed by a 60% increase in the third trimester, indicating that a similar pattern of flux is seen over a wide range of lead concentrations. Analysis of maternal bone and fetal bone, brain, liver, and kidneys confirmed a substantial transplacental transfer of endogenous lead. Lead concentrations in fetal bone often exceeded maternal bone lead concentrations. From 7 to 39% of the lead in the fetal skeleton originated from the maternal skeleton.
Administration, Oral↗
Lead in finger bone, whole blood, plasma and urine in lead-smelter workers: extended exposure range.
OBJECTIVES: To assess the historical exposure and to study the relationships between lead concentrations in whole blood (B-Pb), plasma (P-Pb), urine (U-Pb), finger bone (Bone-Pb) and duration of employment in workers at a secondary lead smelter and to compare the relationships between B-Pb and P-Pb with results from previous studies of populations with a wide range of lead exposure. METHODS: In 39 lead workers (29 active, ten retired), recruited from those with the highest exposure at a German secondary lead smelter, levels of B-Pb, P-Pb and U-Pb were determined by inductively coupled plasma mass spectrometry (ICP-MS). Bone-Pb was determined by in vivo X-ray fluorescence (XRF). Results were compared with data from a previous study on 90 workers (71 active, 19 retired) with lower exposure, from a Swedish secondary lead smelter, as well as with previously collected data from 42 active Russian lead workers and 34 Ecuadorian lead-exposed subjects. RESULTS: The median values in the active/retired German lead workers were: age 44/59 years, duration of employment 20/38 years, Bone-Pb 71/150 microg/g, B-Pb 500/330 microg/l, P-Pb 2.7/1.1 microg/l, and U-Pb 25/13 micromol/mol creatinine. Bone-Pb increased with duration of employment by 4.2 microg/g per year and 1.6 microg/g per year in German and Swedish workers, respectively. The median Bone-Pb was three times higher in both active and retired German workers than in Swedish smelter workers with essentially the same age distribution and duration of employment. The linear regression equation between B-Pb and log P-Pb in the combined group of Ecuadorian, German, Russian and Swedish lead-exposed subjects (n=176) was B-Pb=545 x log[P-Pb] + 258 (r(s)=0.94; P<0.001). CONCLUSIONS: The high Bone-Pb values recorded for the German smelters implied a historical lead exposure of considerable magnitude. The long-term high lead exposure also showed up in the B-Pb levels for both active and retired workers, leading to the implementation of necessary industrial safety measures in order to respond to biological threshold limits. The suggested equation describing the relationship between B-Pb and P-Pb in the combined group of subjects with a wide range of lead exposure can be useful in future cross-sectional and longitudinal studies of lead-exposed populations, relating, e.g., lead exposure to adverse health outcomes.
Adult↗
Impacts of traffic-induced lead emissions on air, soil and blood lead levels in Beirut.
Lead is a purely toxic heavy metal which induces a wide variety of adverse physiologic effects. Nevertheless, it has been mined and used for more than 8,000 years. Among the different contemporary sources of lead pollution, traffic-induced emissions from the combustion of leaded gasoline is of particular concern, as it can constitute more than 90 percent of total lead emissions into the atmosphere in congested urban areas where no phase-out activities have been adopted. Gasoline lead content and traffic volume are strongly correlated with concentrations of lead in various environmental media. In the absence of policies to reduce the use of lead in gasoline or to favor the use of unleaded gasoline, leaded gasoline remains the predominant grade in many countries. This paper assesses the status of lead pollution from the combustion of leaded gasoline in Beirut based on field measurements of lead in air and roadside dust of urban and rural/suburban areas and recent data on soil and blood lead levels. Average atmospheric lead concentrations was about 1.86 microg m(-3) at urban locations and 0.147 microg m(-3) at suburban locations. The analysis of roadside dust revealed an average lead level of 353 microg g(-1) along urban streets and 125 microg g(-1) along rural/suburban roads. Blood lead levels were also relatively high in comparison to countries where leaded gasoline has been phased-out.
Adult↗
Relationship between blood lead concentrations and dietary lead intake in infants: the Glasgow Duplicate Diet Study 1979-1980.
In 1979-1980 a duplicate diet study of 131 infants was carried out in Glasgow where the water was plumbosolvent and water lead levels were known to be often above 100 micrograms/l. The main aim of the study was to establish the form of the relationship between water lead, dietary lead and blood lead in infants. The study was designed so that there was a balanced number of measurements over a wide range of lead intakes. Blood lead concentrations of the mothers were measured as well as those of the infants. Results from the study showed that high values of lead in water, diet and blood were closely associated with each other. Blood lead concentrations appeared to have non-linear (cube root) relationships with water lead concentrations and dietary intakes of lead, with steadily smaller increases in blood lead as amounts or concentrations of ingested lead increased. However, infants who were wholly breast fed showed a much weaker effect of water lead on blood lead. Some diets had much higher lead concentrations than the water lead concentration would have suggested because they had been made up with water from the hot tap (rather than the kitchen cold water tap).
Diet↗
The decay of blood lead levels in workers suspended under the control of lead at work regulations.
AIMS: To study the rate of decline in blood lead levels post-suspension under Control of Lead at Work Regulations (CLAW) and thereby suggest sampling frequencies for follow-up blood lead measurements. METHODS: A retrospective cohort of lead workers with blood lead levels over the current suspension level were identified from blood lead records. Data on their suspension and follow-up blood lead measurements were obtained. RESULTS: Sixteen per cent of the identified cohort did not appear to return to lead work under CLAW. Twenty-seven suspension cases with an initial mean blood lead of 79 microg/dl (3.82 micromol/l) formed the dataset for analysis of decline in blood lead levels. The mean length of time between the blood sample indicating suspension and the first follow-up blood sample was 32 days. The mean length of suspension under CLAW was 61 days. The mean initial rate of blood lead decay was 0.659 microg/dl per day (0.032 micromol/l per day), although with a wide range. The rate of decline in blood lead after suspension was increased by the blood lead level at suspension, but was decreased by increasing past cumulative exposure. CONCLUSIONS: A follow-up blood lead sample 1 month after suspension should show a mean decrease between 13 and 26 microg/dl (0.63-1.25 micromol/l), which is substantially greater than that due to analytical 'noise' associated with two sequential measurements (approximately 5 microg/dl). Therefore, a follow-up blood sample taken around 3-4 weeks after suspension would seem practical. A decrease in blood lead of 7-8 mug/dl (0.36 micromol/l) or less in the month after suspension may suggest continuing lead exposure.
Adult↗
Bone lead as a new biologic marker of lead dose: recent findings and implications for public health.
Measurements of lead in bone have recently become the focus of research because a) bone lead levels serve as a cumulative dosimeter of lead exposure over many years (because of lead's long residence time in bone), and cumulative exposure may be more predictive of chronic toxicity than recent exposure, which is what blood lead levels mostly reflect; b) there is suspicion that heightened bone turnover (e.g. during pregnancy, lactation, and aging) may liberate enough stored lead to pose a significant threat of delayed toxicity; and c) although lead exposure has largely declined in the United States over the past 10 to 15 years, decades of heavy environmental pollution have resulted in significant accumulation of lead in bone among most members of the general U.S. population. Epidemiologic research on the impact of lead stored in bone is now possible with the development of 109Cd K-X-ray fluorescence (KXRF) instruments for the in vivo measurement of lead in bone. In this paper, the KXRF method will be briefly reviewed, followed by a summary of several Superfund-supported studies (and others) of blood lead and KXRF-measured bone lead in which these measures are compared as biologic markers of lead dose. Measurement of bone lead in epidemiologic studies has proved useful in exposure assessment studies, i.e., in identifying factors that contribute most to retained body lead burden, and in investigating cumulative lead exposure as a risk factor for poor health outcomes such as hypertension, kidney impairment, cognitive impairment, behavioral disturbances, and adverse reproductive outcomes.
Biomarkers↗
Breathing zone particle size and lead concentration from sanding operations to remove lead based paints.
The relationship between lead concentration in the dry film of lead based paints applied to steel bulkheads aboard ship, the lead concentration found in the air when the paint is removed by mechanical means, and blood lead concentrations of workers involved in lead based paint removal has not been well characterized. Intuitively a direct relationship must exist but confounding factors confuse the issue. Simultaneous sampling procedures from the same paint removal operation may differ by several orders of magnitude. The process from dried film to aerosol (airborne dust) exposure, and on to dose can be separated into two major phases; (1) generation of the dust and its transport through the air to the worker and (2) uptake and dose related factors within the body. Both phases involve complex interactions and there are a number of factors within each phase that significantly affect the potential lead dose for the worker. This study attempts to clarify the mechanisms involved in the generation and transportation of the dust to the worker by evaluating the relationship of a number of key factors on particle size and lead distribution within the aerosol dust generated when lead based paint is removed by sanding. The study examined the relationship between particle size in the dust and grit size of the abrasive. It also examined the distribution of lead within selected particle sizes. The Mass Median Aerodynamic Diameter (MMAD) was used as an indicator of change in the particle size distribution. Particle size distributions were evaluated using a TSI Aerodynamic Particle Sizer, a five stage cyclone and scanning electron microscopy. Lead distribution was determined using the five stage cyclone, and personal or area samples analyzed using inductively coupled plasma (ICP). Mass concentrations were evaluated using a MIE Mass Concentration Analyzer and gravimetric analysis of filter samples collected in the breathing zone. Student's t-tests were used to evaluate changes in MMADs, mass concentrations and other indices for inter and intra-grit size samples. Correlation coefficients (Pearson's r) were used to determine the relationship between factors. Findings of the research indicated that the particle size distribution in the dust is directly related to the grit size of the abrasive (i.e. inversely related to the abrasive grit number). Particulate mass concentrations of dust varied directly with abrasive grit number. The distribution of lead did not appear to be affected by grit size of the abrasive in that the lead distribution within the particle size ranges remained homogeneous and consistent with the lead concentration in the dried film. Mass concentrations of lead in air samples varied directly with lead concentration in the bulk coating. Results of this project, coordinated with deposition modeling and bioavailability studies will be useful in the development of a model to characterize lead dose to workers based on known parameters within the work specifications.
Aerosols↗
Lead level of whole blood and plasma in workers exposed to lead stearate.
In a group of 23 male workers exposed to lead stearate the levels of lead in whole blood and plasma were determined and compared to those obtained from a group of 23 subjects exposed to inorganic lead compounds. The mean values for lead in whole blood were similar in both groups, while the mean lead concentration in plasma was 0.1729 (SD 0.0677) mumol/l for those exposed to lead stearate and 0.0936 (SD 0.0577) mumol/l for those exposed to other lead compounds. The difference was highly significant. The percentage ratio for lead in plasma to lead in whole blood, which can be considered a "bioavailability index" for lead, proved to be two times higher for stearate workers than for subjects exposed to inorganic lead compounds. The data suggest that the different chemical properties of absorbed lead stearate may cause a different distribution of the metal in different blood compartments, the plasma compartment having a higher affinity for lead stearate than for other lead compounds. Because the plasma fraction has a greater bioavailability, lead stearate could induce toxic effects that differ (possibly being severer) from those caused by other lead compounds at similar absorbed doses.
Air Pollutants, Occupational↗
Prediction of right ventricular and posterior wall ST elevation by coronary care nurses: the 12-lead electrocardiograph versus the 18-lead electrocardiograph.
OBJECTIVES: To determine the value of routine versus selective use of the 18-lead electrocardiogram in determining the size of an acute inferior myocardial infarction (MI). DESIGN: Prospective, quasi-experimental, random assignment. SETTING: The coronary care unit (CCU) of a major teaching hospital in South Australia. PATIENTS: Fifty-two patients admitted to the CCU with acute evolving inferior MI. OUTCOME MEASURES: Correlation and comparison of the predictions of the right ventricular (RV) and posterior wall (PW) lead ST elevation with prospectively chosen markers on the 12-lead electrocardiogram--ST elevation in lead III > II and precordial ST depression, and the predictions by coronary care nurses. PROCEDURE: The results of 18-lead electrocardiograms of 52 consecutive patients admitted to the CCU with acute evolving inferior MI were classified according to prospectively chosen criteria. Coronary care nurses were randomly assigned four 12-lead electrocardiograms and asked to "blindly" predict ST elevation in the concurrent RV and PW leads. RESULTS: ST elevation in lead III > II demonstrated a sensitivity and positive predictive accuracy of 86% to 1 mm of ST elevation in the RV leads. ST depression in V1, V2, and V3 similarly demonstrated a 75% sensitivity and 89% positive predictive accuracy to 1 mm of ST elevation in the PW leads. In comparison, coronary care nurses proved to be as accurate in their predictions of additional PW ST elevation (p = 0.73), but were significantly less able to predict RV ST elevation (p = 0.049). These predictions were independent of the level of experience and qualifications. CONCLUSIONS: Discriminating between smaller and larger types of inferior MIs has the potential to alter patient management: Thirty-two percent of patients in the study demonstrated additional ST elevation in both the RV and PW leads. Both of the 12-lead electrocardiogram markers used in this study proved reasonably accurate in predicting additional ST elevation in the leads that normally comprise the 18-lead electrocardiogram. Recognition of these markers has the potential to expedite the need for the additional 18-lead electrocardiogram when rapid assessment of infarction size is required. However, the routine use of the 18-lead electrocardiogram is supported by this study.
Clinical Competence↗
Comparison of usefulness of computer assisted continuous 48-h 3-lead with 12-lead ECG ischaemia monitoring for detection and quantitation of ischaemia in patients with unstable angina.
AIMS: The selection of ECG leads used for ST monitoring may influence detection and quantitation of ischaemia. METHODS: We compared on-line continuous 48-h 12-lead against 3-lead ST monitoring in 130 unstable angina patients (Mortara. ELI-100). Onset and offset of ST episodes were defined by the lead with the first > or = 100 microV ST change relative to baseline and the lead with the latest return to baseline ST level, respectively. ST episodes were calculated for 12 leads and 3 leads (V2, V5, III) separately. RESULTS: ST episodes were detected in 88 patients (77%) by 12-lead and in 71 patients (62%) by 3-lead ST monitoring (P < 0.02). The median number (25.75%) of episodes/patient was 1 (0.3) for 3-lead and 2 (1.6) for 12-lead (P < 0.0001). The total duration of ischaemia detected during 12-lead far exceeded 3-lead monitoring: 12.3 (1, 58.2) and 1.7 (0, 23.3) min respectively (P < 0.0001). The probability of recurrent ischaemia declined most during the first 24 h of monitoring. After a period without ST changes of 1, 12, 24 and 36 h, the probabilities of recurrent ischaemia were 63, 31, 14 and 9%, respectively. CONCLUSIONS: Continuous 12-lead ST monitoring increases detection rate and duration of ST episodes compared to 3-lead ST monitoring. The use of continuous 12-lead ECG monitoring devices on emergency wards and coronary care units is recommended.
Angina, Unstable↗
Updated appraisal of pacing lead performance from the Danish Pacemaker Register: the reliability of bipolar pacing leads has improved.
The Danish Pacemaker Register was established in January 1982, and the 12 implanting centers in Denmark report to the Register on a continuous basis by use of the European Pacemaker Patient Identification Card. As of August 1999, the Register contained data on 33,164 bradycardia, endocardial, and epicardial (n = 159) lead implants performed in Denmark on 27,738 generators in 24,180 patients for a total of 17,988 (54.2%) ventricular unipolar, 5,610 (16.9%) ventricular bipolar, 2,056 (6.2%) atrial unipolar, and 7,242 (21.8%) atrial bipolar leads. Lead failure was defined as need for replacement or surgical abandonment of the lead due to pacing or sensing problems with the exception of lead displacement. The 10-year survival rate for unipolar leads was 97.2 +/- 0.4% (+/- 2 SE) as compared to 79.6 +/- 3.2% for bipolar leads (P < 0.001). The Medtronic 4012, the Telectronics 284, and the Siemens (Pacesetter) 1010T, 105T, and 1050T bipolar lead models were poor performing leads that needed careful monitoring and appropriate replacement. Excluding those five poor performing bipolar leads, the models yielded a 10-year survival rate of 94.3 +/- 2.4% for bipolar leads. The 5-year survival for all bipolar leads implanted after January 18, 1993 (this was the date that the last of the five poor performing bipolar lead models were implanted in Denmark) was 98.7 +/- 0.4% compared with 98.9 +/- 0.3% for all unipolar leads implanted after January 18, 1993 and 86.8 +/- 1.6% for all bipolar leads implanted on or before January 18, 1993. These results indicate a significant improvement in bipolar lead reliability.
Actuarial Analysis↗
The accuracy of a lead questionnaire in predicting elevated pediatric blood lead levels.
OBJECTIVES: To determine the prevalence of elevated blood lead levels and to evaluate the accuracy of a lead screening questionnaire in a western United States urban inner-city pediatric population. DESIGN: A convenience sample of children between the ages of 6 months and 6 years seen for a well-child visit were enrolled. Venous blood lead levels were measured and a lead screening questionnaire was completed. SETTING: The primary care clinics of the 10 community health centers of the city and county of Denver, Colorado. Approximately 85% of children receiving services are below the 150% poverty level and 54% are insured through the state's Medicaid program. SUBJECTS: A total of 2978 children seen for a well-child visit from February 1993 to January 1994. MAIN OUTCOME MEASURES: The prevalence of elevated blood lead levels and the operating characteristics of both the Centers for Disease Control and Prevention lead screening questionnaire and the complete questionnaire used in Denver, using venous blood lead levels as the criterion standard. RESULTS: The mean blood lead level was 0.20 mumol/L (4.19 micrograms/dL). Eighty-five children had blood lead levels of 0.48 mumol/L (10 micrograms/dL), representing 2.9% of the study group (95% confidence interval [CI], 2.3-3.5). Only 0.3% of the cohort had blood lead levels greater than 0.96 mumol/L (20 micrograms/dL). The sensitivity, specificity, and positive predictive value of the Centers for Disease Control and Prevention questionnaire was 57%, 51%, and 3%, respectively. The sensitivity, specificity, and positive predictive value of the complete questionnaire was 59.7%, 36%, and 2.6%, respectively. The marginal cost of identifying a child with a blood lead level greater than 0.96 mumol/L (20 micrograms/dL) was $4925. CONCLUSIONS: Few of the low-income children in this study had blood lead levels greater than 0.48 mumol/L (10 micrograms/dL). The questionnaire did little better than chance at predicting the presence or absence of elevated blood lead levels and cannot replace a blood lead level test for childhood lead screening in this community.
Adolescent↗
Effects of iron deficiency on lead excretion in children with moderate lead intoxication.
The effect of iron status on calcium disodium edetate (CaNa2EDTA)-induced lead diuresis was examined in 112 children with moderate lead intoxication. Patients whose blood lead levels were between 25 and 55 micrograms/dl and who had erythrocyte protoporphyrin concentrations greater than or equal to 35 micrograms/dl underwent provocative testing to determine the need for a full course of chelation therapy. A blood sample for lead, erythrocyte protoporphyrin, and serum ferritin determinations was obtained immediately before the intramuscular administration of CaNa2EDTA, 500 mg/m2. Determination of urinary lead level was based on an 8-hour urine collection. Blood lead and ferritin levels were significantly correlated with urinary lead excretion: r = 0.542 and 0.298, respectively, p less than 0.01 for both. Multiple regression models were tested to assess the independent effects of the variables. With blood lead level controlled, ferritin remained significantly associated with urinary lead excretion; for every 1 ng/ml increase in ferritin, urinary lead increased by 2.4 micrograms. This small effect of ferritin on urinary lead was illustrated in a discriminant analysis. Using blood lead level by itself as the independent variable resulted in a 76% correct assignment of provocative test outcomes. Knowing the ferritin level improved this assignment accuracy by only 3%. We conclude that the iron status, as measured by serum ferritin, of children with moderate lead intoxication, has a small but significant effect on CaNa2EDTA-induced lead diuresis. This effect may influence the interpretation of borderline provocative test outcomes. Although chelation therapy should not be withheld pending treatment of iron deficiency, lead stores should be reassessed after iron repletion.
Anemia, Hypochromic↗