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PubMed2006

Blood lead levels in children and environmental lead contamination in Miami inner city, Florida.

Studies have shown that the environmental conditions of the home are important predictors of health, especially in low-income communities. Understanding the relationship between the environment and health is crucial in the management of certain diseases. One health outcome related to the home environment among urban, minority, and low-income children is childhood lead poisoning. The most common sources of lead exposure for children are lead paint in older, dilapidated housing and contaminated dust and soil produced by accumulated residue of leaded gasoline. Blood lead levels (BLL) as low as 10 microg/dL in children are associated with impaired cognitive function, behavior difficulties, and reduced intelligence. Recently, it is suggested that the standard for intervention be lowered to BLL of 5 microg/dl. The objectives of our report were to assess the prevalence of lead poisoning among children under six years of age and to quantify and test the correlations between BLL in children and lead exposure levels in their environment. This cross-sectional analysis was restricted to 75 children under six years of age who lived in 6 zip code areas of inner city Miami. These locations exhibited unacceptably high levels of lead dust and soil in areas where children live and play. Using the 5 microg/dL as the cutoff point, the prevalence of lead poisoning among the study sample was 13.33%. The study revealed that lead levels in floor dust and window sill samples were positively and significantly correlated with BLL among children (p < 0.05). However, the correlations between BLL and the soil, air, and water samples were not significant. Based on this pilot study, a more comprehensive environmental study in surrounding inner city areas is warranted. Parental education on proper housecleaning techniques may also benefit those living in the high lead-exposed communities of inner city Miami.

Child, Preschool↗
PubMed1991

The effect of airborne lead particle size on worker blood-lead levels: an empirical study of battery workers.

Theoretical models and experimental data suggest that the particle size distribution of lead aerosols should affect the lead dose absorbed by exposed workers. In the present study, 44 workers in five major operations in a high-volume, lead-acid battery plant were studied for the influence of lead aerosol size on lead-in-blood (PbB) levels. A multiple linear regression analysis based on particle size assumptions made in the model used by the Occupational Safety and Health Administration to help select the permissible exposure level (PEL) for lead showed no improvement in prediction of PbB over that already present without any consideration of particle size. The use of the American Conference of Governmental Industrial Hygienists (ACGIH) regional size-selective criteria also failed to improve the prediction of PbB. However, when deposition models developed by Heyder et al were used in which the lead aerosol was separated into alveolar and extra-alveolar fractions, corresponding to what is considered respirable and ingestible lead, the coefficient of determination (R2) associated with the fractionated lead particulate increased approximately 25% over that attributable to only the total lead concentration. In addition, the deposition model, which closely matched the ACGIH reference worker criteria, resulted in ratios of the coefficients for the respirable to ingestible lead contributions to PbB that appeared to agree with experimental data, suggesting approximately a 10 to 1 ratio in absorption efficiency of the lung versus the gastrointestinal tract.

Aerosols↗
PubMed1982

Effect of hunters' switch from lead to steel shot on potential for oral lead poisoning in ducks.

Mallards and black ducks (n = 409) killed by hunters during the 1980 and 1981 hunting seasons in Pennsylvania (Susquehanna River and Crawford County) were examined to evaluate the effectiveness of regulations that converted the studied areas from lead to steel shotgun pellets in 1977-1978. Gizzards were examined for ingested lead and steel shot, and liver specimens were analyzed for lead. Since there is no evidence to suggest that ducks preferentially ingest steel or lead shot, it was concluded that ducks with steel shot would have contained lead shot. Therefore, we concluded that the conversion to steel shotgun pellets accounted for the decreased prevalence of ingested lead shot from 11.2% to 5.6%. Toxic concentrations of lead (greater than or equal to 6 ppm, wet weight) in the liver were found in 6 of 23 ducks that contained lead shot, whereas only 2 of 386 ducks without lead pellets had toxic concentrations. It was concluded that the conversion to steel shotgun pellets in the studied areas probably has decreased the exposure of ducks to lead shot, thereby decreasing the potential for lead poisoning.

Animals↗
PubMed1988

Optimal lead subsets for reconstruction of QRS and ST-T in 35-lead precordial maps.

Precordial maps have been used for some 15 years to estimate the extent of myocardial injury in patients with acute anterior or lateral wall infarction. Estimates have been based on various QRS- and ST-T-derived parameters, including amplitude sum of ST elevations. Application of the electrodes, commonly 35, is cumbersome and time-consuming with the critically ill. A subset of 5 or 7 selected leads can be applied instead, and the remaining leads calculated from that subset with minimal loss of QRS and ST-T information. Maps were recorded from 100 patients within 72 hours of onset of anterior or lateral infarct. Optimal lead subsets for QRS and ST-T feature extraction were found by the sequential selection method of Lux. Subsets numbering between 2 and 15 leads were derived, with their lead-transform coefficients. Measures to estimate goodness of fit for reconstructed leads included correlations, error-to-signal ratios and root-mean-square errors. These measures were calculated separately over the QRS and ST-T complexes. Reconstructions from a 7-lead subset had a mean 0.92 correlation with ST-T in the original leads and root-mean-square error of only 0.04 mV. Sum of ST elevation differed by only 2% between original leads and reconstructions based on 5 or more leads. To confirm repeatability, lead-transform coefficients were also calculated from a training population of 50 patients and applied to the maps of the other 50.

Electrocardiography↗
PubMed1983

Two mouse hybridoma antibodies against human milk-fat globules recognise the I(Ma) antigenic determinant beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6).

Two mouse hybridoma antibodies (LICR-LON-M39 and LICR-LON-M18) against the human-milk-fat globules were found to resemble human autoantibodies of anti-I type in their cold agglutinating property and their preferential reactions with erythrocytes of I- rather than i-type. From inhibition of binding assays with glycoproteins having known A, B, H, Lea, Leb, I, and i activities, and oligosaccharides of the Type 1 and Type 2 lacto-N-glycosyl series, it was established that these antibodies are directed at Type 2 structures, and that the I(Ma) determinant, beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6), which is usually found on branched oligosaccharides, is the preferred sequence. The hybridoma antibodies as well as anti-I Ma were shown to react well with the beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 6)-D-Gal or -D-Man sequence. Studies of the reactions of these antibodies with glycolipids on thin-layer plates showed that the two hybridoma antibodies differ from anti-I Ma in reacting weakly with the unbranched i-type sequence beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-Galp-(1 leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-galp-(1 leads to 4) as found on lacto-N-norhexasylceramide. Furthermore, they differ from anti-I Ma but resemble anti-I Woj and Sti, and a hybridoma antibody 1B2 in their failure to react with their determinant in the presence of alpha-D-(1 leads to 3)-linked galactosyl groups. From their lack of reactions with blood-group-A and -H active glycoproteins, and their reactions with neuraminidase-treated erythrocytes, it was deduced that the determinants recognised by the two hybridoma antibodies are also masked in the presence of alpha-L-(1 leads to 2)-linked fucosyl groups and sialic acid.

Animals↗
PubMed1988

Calcium-lead interactions involving earthworms. Part 1: The effect of exogenous calcium on lead accumulation by earthworms under field and laboratory conditions.

Earthworms (Lumbricus rubellus and Dendrodrilus rubidus) were collected from several acidic and calcareous abandoned ferrous metalliferous mine sites. Tissue lead concentrations were substantially lower than the total soil lead concentrations, except at one site (Cwmystwyth) where the tissue lead concentrations of both species were approximately 5 to 10 times higher than that of the soil. Soil lead was the major factor in determining the tissue lead concentration, although it was demonstrated that both soil pH and soil calcium concentration could markedly increase the % variance in tissue lead concentration. These findings help explain the apparent anomaly in tissue lead concentrations of earthworms from Cwmystwyth, where the soil is acidic and has exceptionally low calcium concentrations. Soil-liming experiments provided supportive evidence that soil pH, coupled with soil calcium, influences lead accumulation by earthworms, but a filter paper feeding experiment provided unequivocal evidence that soil calcium concentration alone can influence lead accumulation by earthworms. It is concluded that, although lead accumulation by earthworms is influenced by both physico-chemical and biochemical mechanisms, the latter over-rides the former, i.e. soil calcium is more important factor in determining the accumulation of lead earthworms than is soil pH.

Journal Article↗
PubMed2000

Transvenous left ventricular lead implantation with the EASYTRAK lead system: the European experience.

Several independent studies suggest that resynchronization therapy--achieved by left- or biventricular pacing--improves hemodynamics in heart failure patients with interventricular conduction disturbances. Delivery of this new therapy in an effective and minimally invasive manner presents technical challenges, as transvenous access to the left ventricle is required. Since 1999, a novel over-the-wire approach combining standard pacing lead and angioplasty technology has been evaluated in several European countries. This new left ventricular lead, the EASYTRAK system (Guidant, St. Paul, MN), has been clinically evaluated in 2 phases. The first phase was a clinical investigation to obtain the CE-mark (i.e. European Commission approval). The second phase, which started immediately after the CE-mark was obtained, consisted of a postmarket surveillance called the European registry. This article reports on the results of the pre-CE-mark clinical investigation and the preliminary results of the European registry (first 150 patients). During the pre-CE-mark clinical investigation of the EASYTRAK system, lead performance was assessed in 36 successfully implanted patients. The patients had indications for VVI-pacing, symptoms of heart failure and significant left ventricular dysfunction. The left ventricular lead was implanted in conjunction with a conventional right ventricular lead and a new heart failure device (CONTAK TR, Guidant, Brussels, Belgium). Lead measurements (threshold, sensing, and impedance) were performed at implant and subsequent follow-ups. The stimulation thresholds at 0.5 msec impulse width were acceptable, although (as expected) slightly higher than with standard right ventricular pacing leads: 1.39 +/- 1.15 V at implant, 1.72 +/- 1.26 V at predischarge, 1.54 +/- 0.88 V at 2 weeks, 1.38 +/- 0.80 V at 6 weeks, and 1.24 +/- 0.73 V at 12 weeks. R-wave and impedance measurements were stable over time. A revision of the EASYTRAK lead was required in 3 patients. No perforations were observed. During the second phase of the European registry, 150 implants were attempted in 63 centers from November 1999 to January 2000. The EASYTRAK was implanted with a pulse generator offering, in addition to resynchronization therapy, either tachycardia monitoring (CONTAK TR) or implantable cardioverter defibrillator therapy (CONTAK CD), depending on the patient indication. Over half of the centers involved had not previously implanted the EASYTRAK system. Total implant success rate was 83% (135/150), skin-to-skin duration of the implant was 169 +/- 81 minutes (range, 53-480 minutes), with a clear learning curve. Once the coronary sinus was found, the implant success rate was 92%. One lead dislodgment and 2 cases of phrenic nerve stimulation were reported. We conclude that the new EASYTRAK lead design for transvenous left ventricular lead implantation seems to be a suitable and safe tool for delivering resynchronization therapy to heart failure patients.

Aged↗
PubMed1999

Pacemaker lead extraction with the laser sheath: results of the pacing lead extraction with the excimer sheath (PLEXES) trial.

OBJECTIVES: The purpose of this study was to evaluate the safety and effectiveness of pacemaker lead extraction with the excimer sheath in comparison to nonlaser lead extraction. BACKGROUND: Fibrotic attachments that develop between chronically implanted pacemaker leads and to the venous, valvular and cardiac structures are the major obstacles to safe and consistent lead extraction. Locking stylets and telescoping sheaths produce a technically demanding but effective technique of mechanically disrupting the fibrosis. However, ultraviolet excimer laser light dissolves instead of tearing the tissue attachments. METHODS: A randomized trial of lead extraction was conducted in 301 patients with 465 chronically implanted pacemaker leads. The laser group patients had the leads removed with identical tools as the nonlaser group with the exception that the inner telescoping sheath was replaced with the 12-F excimer laser sheath. Success for both groups was defined as complete lead removal with the randomized therapy without complications. RESULTS: Complete lead removal rate was 94% in the laser group and 64% in the nonlaser group (p = 0.001). Failed nonlaser extraction was completed with the laser tools 88% of the time. The mean time to achieve a successful lead extraction was significantly reduced for patients randomized to the laser tools, 10.1 +/- 11.5 min compared with 12.9 +/- 19.2 min for patients randomized to nonlaser techniques (p < 0.04). Potentially life-threatening complications occurred in none of the nonlaser and three of the laser patients, including one death (p = NS). CONCLUSIONS: Laser-assisted pacemaker lead extraction has significant clinical advantages over extraction without laser tools and is associated with significant risks.

Aged↗
PubMed1999

Percutaneous extraction of transvenous defibrillator leads using the VascoExtor pacing lead removal system.

In the implantable cardioverter defibrillator era the necessity for lead removal is not negligible. A specially designed extraction lead system for percutaneous removal of such leads is lacking, in contrast to the existing pacing lead extraction systems. We report the successful percutaneous extraction of four implantable cardioverter defibrillator leads in three patients because of lead malfunction using a novel pacemaker lead extraction system, the VascoExtor (VascoMed) system. Three leads were successfully removed in two patients using traction with special locking stylets from the superior approach. One lead was removed using the system's additional extraction tools through the femoral approach. There were no complications. This preliminary experience shows that the VascoExtor (VascoMed) pacemaker lead extraction system can also be used in implantable cardioverter defibrillator lead extraction safely and effectively. In addition to the locking stylets, adjunct percutaneous extraction tools may be needed in some cases.

Cardiovascular Surgical Procedures↗
PubMed2002

Malfunction of endocardial defibrillator leads and lead extraction: where do they meet?

AIMS: The development of new extraction techniques has improved the success rate of intravascular extraction of pacemaker and defibrillator leads, and hence the practice of extraction is expanding. However, the indications for lead extraction of malfunctioning leads in patients with an implantable cardioverter defibrillator (ICD) are still not well established. METHODS AND RESULTS: We reviewed the literature concerning structural complications of ICD leads. The clinical presentation and detection of malfunction is discussed as well as the consequences for adequate defibrillation therapy. An overview of the current published experience of intravascular extraction of ICD leads is provided including a brief discussion of our own experience. CONCLUSION: From this overview we conclude that malfunctioning pace-sense or ICD leads can be left in situ if there are no uncovered insulation defects. Inserting a new pace-sense or ICD lead is preferable in this situation given the current known complication rate of lead extraction. Lead extraction should be reserved for damaged leads in which interference with proper detection or defibrillation of newly inserted leads cannot be excluded.

Arrhythmias, Cardiac↗
PubMed1983

Idiotype-antiidiotype regulation. V. The requirement for immunization with antigen or monoclonal antiidiotypic antibodies for the activation of beta 2 leads to 6 and beta 2 leads to 1 polyfructosan-reactive clones in BALB/c mice treated at birth with minute amounts of anti-A48 idiotype antibodies.

The anti-beta 2 leads to 6 fructosan antibodies sharing the idiotypes (Id) of ABPC48 (A48) monoclonal protein represent a silent fraction of the anti-beta 2 leads to 6 fructosan repertoire, since these antibodies cannot be detected during a conventional immune response elicited by bacterial levan (BL). However, the administration at birth of minute amounts of anti-A48 Id antibodies causes a long-lasting activation of A48 Id+-bearing clones. This activation is related to direct interaction of anti-A48 Id antibodies with precursors bearing the A48 Id+ immunoglobulin receptor, since an A48 Id+ response can be transferred with highly purified B cells in lethally irradiated mice. The maturation of these precursors into A48 Id+ anti-beta 2 leads to 6 fructosan antibody-secreting cells requires challenge by the antigen. Isoelectric focusing (IEF) data showed that in 1-mo-old mice an UPC10 (U10)-like spectrotype was observed, whereas in 3-mo-old mice, a new spectrotype binding BL rather than inulin (In) was identified. This spectrotype was observed only in CXBJ mice, the single strain in which an A48 Id+ response was observed. The antigenic challenge can be replaced by a monoclonal anti-A48 Id antibody (i.e., 17-38). Interestingly, in 1-mo-old BALB/c mice treated with anti-A48 Id antibodies, the challenge with 17-38 monoclonal antibody led to the activation of A48 Id- anti-beta 2 leads to 6 fructosan-reactive clones with BALB/c type IEF spectrotypes, whereas in 3-mo-old BALB/c mice treated with anti-A48 Id antibodies, the challenge with 17-38 monoclonal antibody led to the activation of W3082 IdX+ anti-beta 2 leads to 6 and beta 2 leads to 1 fructosan-reactive clones. In these animals, inhibition of A48 Id+ anti-beta 2 leads to 6 fructosan clones was observed. This antibody probably represents a homobody carrying the internal image of the antigen, which through its paratope suppresses the A48 Id+ response and through its Id activates an A48 Id- anti-beta 2 leads to 6 fructosan response in 1-mo-old mice and in 3-mo-old mice leads to an anti-beta 2 leads to 6 and beta 2 leads to 1 fructosan response dominated by the W3082 IdX.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Chronic ventricular electrograms: do steroid-eluting leads differ from conventional leads?

The aim of steroid-eluting leads is to reduce chronic pacing thresholds. Whether steroid-eluting leads also modify acute and chronic R wave amplitudes as well as R wave sensing of the pulse generator was investigated in 31 patients with a unipolar ventricular pacemaker. Four different leads were implanted: Two steroid-eluting leads with different electrode surface areas (8 mm2 and 5.8 mm2) and two conventional leads (Target Tip, Elgiloy lead). At implantation filtered R wave amplitudes, peak-to-peak values, and slew rates were measured by a pacing system analyzer. One year after implantation R wave amplitudes were directly determined from intracardiac electrograms and compared to the peak-to-peak data at implantation. Additionally, R wave inhibition was evaluated at a sensitivity setting of 5 mV. There were no differences among the four leads in respect to any of the parameters studied at implantation. At follow-up, no differences in R wave amplitudes were found leading to an appropriate sensing in all leads. Steroid-eluting leads did not differ from conventional leads and a smaller electrode surface area of 5.8 mm2 had no influence on ventricular electrogram. Together with a pacemaker with an input impedance of 37 kohms R wave sensing was a correct setting of 5 mV.

Aged↗
PubMed1997

Comparison of electrical characteristics between a steroid-eluting single-pass VDD lead and a standard steroid-eluting ventricular lead. Thera Pacemaker Study Group.

Compared to regular ventricular leads, single-pass VDD leads have two additional floating electrodes proximal to the ventricular tip, which enables them to detect atrial signals. Because of the latter, VDD leads are thicker than ventricular leads, which could affect ventricular pacing. The purpose of the present study was to compare ventricular pacing of a steroid-eluting single-pass VDD lead (CapSure VDD, Medtronic; n = 107) with the same steroid-eluting regular lead (CapSure SP, Medtronic; n = 39) implanted in the ventricle; both leads were connected to the same types of pacemakers. At implantation, pacing thresholds were measured at 0.5-ms pulse duration and impedance by means with the PSA. At discharge, as well as after 1 and 3 months, pulse duration thresholds were determined at 2.5 V pulse amplitude and impedance by telemetry. At implantation, pacing thresholds and impedance were not different in the VDD (0.38 +/- 0.16 V; 691 +/- 122 omega) and ventricular lead group (0.44 +/- 0.17 V; 648 +/- 150 omega). During follow-ups, no differences in pulse duration threshold were detected between the two groups neither at discharge (VDD = 0.05 +/- 0.03 ms; ventricular 0.05 +/- 0.02 ms), nor after 1 (VDD = 0.05 +/- 0.02 ms; ventricular 0.08 +/- 0.07 ms) and 3 months (VDD = 0.06 +/- 0.03 ms; ventricular 0.09 +/- 0.10 ms). There were also no significant differences for impedance at discharge (VDD = 675 +/- 113 omega; ventricular = 594 +/- 113 omega), after 1 (VDD = 678 +/- 131 omega; ventricular = 627 +/- 112 omega) and 3 months (VDD = 652 +/- 99 omega; ventricular = 628 +/- 105 omega). Pacing thresholds and impedance were neither significantly different at implantation nor during follow-ups between patients with steroid-eluting VDD leads and patients with an equivalent ventricular lead indicating that the thicker VDD lead does not affect ventricular pacing.

Aged↗
PubMed1976

Comparison of 12-lead and computer-analysed 3 orthogonal lead electocardiogram in coronary artery disease.

The computer-analysed 3 orthogonal lead system ("3-lead ECG") provides a rapid and consistent interpretation of the electrocardiogram. In 102 patients undergoing selective coronary arteriography, the ability of such a system to predict the presence of absence of coronary artery disease and the site of myocardial ischaemia was compared with that of the conventional scalar electrocardiogram interpreted by cardiologists ("12-lead ECG"). Each system predicted the site of myocardial ischaemia with equal accuracy. The 3-lead ECG was a more sensitive index (3-lead ECG sensitivity=77%; 12-lead ECG sensitivity=70%) but less specific (3-lead ECG specificity=74%; 12-lead ECG specificity=78%). In coronary artery disease, the predictive "index of merit" for the 3-lead ECG was 0-51, compared with 0-48 for the 12-lead ECG. These results provide further justification for the routine use of the 3 orthogonal lead electrocardiogram.

Adult↗
PubMed1979

Clinically practical lead systems for improved electrocardiography: comparison with precordial grids and conventional lead systems.

The use of limited leads for estimating total body surface potential distributions was investigated as a practical solution to the problem associated with extensive electrocardiographic sampling used in surface potential mapping. Two practical, limited lead sets of 32 leads each were derived and contrasted to a set of 30 precordial leads similar to those used in ST-segment and QRS mapping for estimating infarct size, and to a set of nine leads simulating those used in conventional 12-lead examinations. The two arrays, one of which excluded posterior sites for use in recumbent patients, showed little difference in ability to estimate 192 lead measured maps (average rms voltage error of 35 muV and average correlation coefficient of 0.97). The 30- and 9-lead arrays consistently showed twice the voltage (72 muV) and poorer pattern estimation (average correlation coefficient of 0.91) than either of the 32 lead arrays. These findings indicate the need for 20-35 properly located electrodes for accurate total body surface potential estimation. They also show that there is no difference in the abilities of a 30-lead precordial array and conventional leads to estimate maps.

Arrhythmias, Cardiac↗
PubMed1989

Lead exposure among lead-acid battery workers in Jamaica.

To assess lead exposure in the Jamaican lead-acid battery industry, we surveyed three battery manufacturers (including 46 production workers) and 10 battery repair shops (including 23 battery repair workers). Engineering controls and respiratory protection were judged to be inadequate at battery manufacturers and battery repair shops. At manufacturers, 38 of 42 air samples for lead exceeded a work-shift time-weighted average concentration of 0.050 mg/m3 (range 0.030-5.3 mg/m3), and nine samples exceeded 0.50 mg/m3. Only one of seven air samples at repair shops exceeded 0.050 mg/m3 (range 0.003-0.066 mg/m3). Repair shop workers, however, had higher blood lead levels than manufacturing workers (65% vs. 28% with blood lead levels above 60 micrograms/dl, respectively). Manufacturing workers had a higher prevalence of safe hygienic practices and a recent interval of minimal production had occurred at one of the battery manufacturers. Workers with blood lead levels above 60 micrograms/dl tended to have higher prevalences of most symptoms of lead toxicity than did workers with lower blood lead levels, but this finding was not consistent or statistically significant. The relationship between zinc protoporphyrin concentrations and increasing blood lead concentrations was consistent with that described among workers in developed countries. The high risk of lead toxicity among Jamaican battery workers is consistent with studies of battery workers in other developing countries.

Adult↗
PubMed1998

The impact of low technology lead hazard reduction activities among children with mildly elevated blood lead levels.

This prospective environmental intervention study was conducted to determine the impact of low-technology lead hazard reduction activities among children with mildly elevated blood lead levels. Children whose homes had severe lead hazards were automatically assigned to the intervention group. Children whose homes had lesser hazards were randomly assigned to the intervention group or comparison group. The one-time intervention focused mainly on cleaning and repainting window areas and educating caregivers to maintain effective housekeeping techniques. Changes in blood lead and dust lead loading levels were observed following the interventions. Analysis of covariance was used to adjust comparisons of postintervention levels for preintervention levels and other variables. The lead hazard reduction activities were associated with a modest decline in blood lead levels among children with severe hazards. The magnitude of the decline depended on the confounder that was controlled; the majority ranged from-1.1. to-1.6 microgram/dL. A moderate reduction in window well dust lead loading levels was also observed. While low-technology lead hazard reduction measures appeared to be an effective secondary prevention strategy among children with severe household lead hazards, larger studies are needed to confirm these results.

Boston↗
PubMed1996

Lead levels in bone and hair of rats treated with lead acetate.

The use of hair and bone as media in evaluation of lead exposure was investigated in this study. For 12-16 wk rats were given tap water containing lead acetate in the following concentrations: 41.7 mg Pb/L, 83.3 mg Pb/L, and 166.6 mg Pb/L. The animals were sacrificed every 4 wk and their tibia bones and hair were collected for determination of lead content. In control animals, the lead level amounted to 1.2 micrograms/g (range 0.8-1.3 micrograms/g) and 0.7 microgram/g (range 0.4-2.0 micrograms/g) in bone and hair, respectively. In the treated rats the accumulation of lead in bone and hair occurred in a dose-dependent manner. A positive correlation (r = 0.876) was established between the lead levels in bone and hair of the rats. The regression equation was as follows: microgram Pb/g bone = 0.842 x microgram Pb/g hair + 1.868. After discontinuation of exposure, a significant decrease in the lead content in bone and hair was noticed. About 9 wk after cessation of treatment, the lead content in hair declined to the pre-exposure level, but 64% of the maximal lead concentration did remain in bone. The results of this study indicate that during a continuous exposure the lead level in hair reflects its content in bone. Such phenomena did not occur during the post-exposure period.

Administration, Oral↗