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At least 73 records · Page 4Linked to original sources
PubMed2002

Comparability of 12-lead ECGs derived from EASI leads with standard 12-lead ECGS in the classification of acute myocardial ischemia and old myocardial infarction.

We compared 12-lead electrocardiograms (ECGs) derived with an improved transformation matrix from EASI leads and standard 12-lead ECGs in the detection of acute myocardial ischemia and old infarction (MI). For the ischemia test, we used ECGs of 40 patients recorded prior to and at peak inflation during percutaneous transluminal coronary angioplasty, and for old MI we used test ECGs of 382 non-MI subjects and of 472 patients with prior MI documented by enzyme findings. Two experienced ECG readers served as separate, independent standards for lead-set comparisons, and the Philips ECG analysis program also classified the ECGs. The results showed no significant differences between the two lead sets in the detection of acute inflation-induced ischemia or of old MI according to coding by the electrocardiographers or the computer program. No significant differences were found between the electrocardiographers and the lead sets for acute ischemia. Classification differences between the electrocardiographers were larger than those between the lead sets for acute and old MI and were significant for the latter (P <.001). A more detailed comparison of the lead sets suggested a possible need for modified old-MI criteria and optimization of ST classification thresholds for acute ischemic injury, specific for the EASI 12-lead ECG. We conclude that the EASI-derived 12-lead ECG deserves serious consideration as an alternative to the standard 12-lead ECG in emergency situations and for monitoring in acute-care setting.

Electrocardiography↗
PubMed1981

[Relationship between lead concentration in the air and blood lead levels of people living and working in the centre of a city (Frankfurt blood lead study). II. Correlations and conclusions (author's transl)].

The correlation analysis of the relationship between blood lead levels and lead-in-air concentrations measured in three winter periods showed a highly significant association despite a generally loose dependence of the variables. The regression equations clearly show that there would be a finite residual blood lead value even with completely lead-free air. In the case of the populations exposed to motor traffic in this study, this residual blood lead value is 80--90% of the initial value prior to the decrease in immission. The regression equations, statistically yield results which compare convincingly with ones obtained from model calculations based on studies of metabolism and respiratory physiology. The correlation between the observed changes in blood lead and the initial absolute values of blood lead concentration demonstrates with high statistical certainty that the higher the initial level, the greater was the observed change. This type of association also implies that there is a lower limit value of blood lead below which the decrease in blood lead changes to an increase despite reduction of lead-in-air.

Air Pollutants↗
PubMedDate not supplied

The speciation of lead in erythrocytes in relation to lead toxicity: case studies of two lead-exposed workers.

Lead toxicity is known to be subject to individual susceptibility. This study compares two lead-exposed subjects, one (A; blood Pb 1800 micrograms/L) who remained totally asymptomatic, the other (B; blood Pb 1610 micrograms/L) who showed symptoms of toxicity. We have assessed the speciation of lead in the intra-erythrocyte proteins in these patients and have examined its significance in relation to clinical toxicity. Chromatographic separations of erythrocyte haemolysates from these patients showed a metallothionein-like lead containing protein. It was demonstrated that in patient A, most (approximately 70%) of the erythrocyte lead was associated with this protein, whilst in patient B the protein only contained about 20% of the total lead, with significant amounts bound to high molecular weight proteins, including Hb. Further purification of this protein from each patient showed it to contain a number of constituents, one in particular being the major lead-binding species. This component was more abundant in patient A and, relative to patient B, contained a higher proportion of lead. These results suggest that this protein may act to sequester lead into a non-bioavailable form, hence protecting the body from lead toxicity as with patient A.

Adult↗
PubMed2006

The effectiveness of low-cost soil treatments to reduce soil and dust lead hazards: The Boston lead safe yards low cost lead in soil treatment, demonstration and evaluation.

The Boston lead safe yards low cost lead in soil treatment, demonstration, and evaluation was developed to explore the viability and effectiveness of low-cost soil interventions to reduce exposure to soil lead hazards. Buildings that had been abated for lead to Massachusetts's deleading standards in the previous 5 yrs and met other program requirements were recruited for the evaluation. Following individual property assessments, yards were treated with application of ground coverings and ground barriers in 2000-2001 and followed up at 1 yr. The treatment cost ranged from 1095 dollars to 5643 dollars with an average of 2798 dollars. Soil lead levels at the building dripline, measured with a field-portable X-ray fluorescence analyzer (Niton Model 702 Spectrum Analyzer), dropped from 2021 PPM at baseline to 206 PPM at 1-yr follow-up. Most of the barrier treatments continued to block access to the lead-contaminated soil at 1yr. At the follow-up, few properties with grass treatment had areas that were completely bare, but 28% had more than a small amount of treated areas bare. Treatments were effective in reducing entryway dust lead in the rear of the building if the residents reported they had maintained the yard treatments. Each additional yard work activity reported was predicted to lower 1-yr floor dust lead loading at the rear common/main and dwelling unit entries by about 20%. Each additional 100 ft2 of yard treated was predicted to lower 1-yr floor dust loading at the rear dwelling unit entry by 19%. Treatments did not show a dust lead effect at 1 yr in the front entryway of the building, but the investigators believe that this may be due to the effect of resident cleaning overshadowing the treatment effect.

Boston↗
PubMed1988

An intra-erythrocytic low molecular weight lead-binding protein in acute and chronic lead exposure and its possible protective role in lead toxicity.

A low-molecular-weight protein was measured in erythrocytes from workers with chronic and recent lead exposure, with and without clinical lead toxicity, and from a group of control subjects not exposed to undue environmental lead. The protein was detected in all the workers, but in significantly smaller amounts in those with symptoms, and was absent from controls. The synthesis of the protein is induced at blood lead concentrations above 1.9 mumol/L, but is reduced in workers susceptible to clinical lead toxicity at blood lead concentrations below 4.0 mumol/L. The activity of the red blood cell dithiothreitol (DTT)--activated 5-aminolaevulinate dehydratase (ALA-D) was correlated with the concentration of the low-molecular-weight protein, with both being particularly low in the symptomatic workers. Previous studies have shown that the protein binds lead. By sequestrating excess lead into a non-toxic form, the protein may have a protective role in preventing clinical, and reducing biochemical, lead toxicity.

Adult↗
PubMed2005

Comparison of EASI-derived 12-lead electrocardiograms versus paramedic-acquired 12-lead electrocardiograms using Mason-Likar limb lead configuration in patients with chest pain.

INTRODUCTION: Monitoring or serial 12-lead electrocardiogram (ECG) recordings are the accepted requirement for prehospital data acquisition in patients with chest pain. The purpose of this study was to determine whether waveforms and clinical triage decision are similar in EASI-derived ECGs and paramedic-acquired 12-lead ECGs using Mason-Likar limb lead configuration when compared with standard 12-lead ECGs (stdECG). METHOD: Twenty patients with chest pain had a prehospital 12-lead ECG recorded in the ambulance, and paramedic-applied electrodes retained in place at hospital arrival. An ECG technician applied standard precordial and EASI electrodes in their correct positions. Twelve-lead ECGs were obtained from the paramedic-applied electrodes, using their Mason-Likar limb lead configuration, and derived from the EASI leads for comparison with the stdECG. Three computer-measured QRS-T waveform parameters were considered, and differences in waveform measurement between EASI and stdECG (EASIDeltastdECG) versus differences in waveform measurements between paramedic Mason-Likar and stdECG (PMLDeltastdECG) were calculated. Two physicians determined whether the EASI-derived or the paramedic Mason-Likar ECG contained information that would change their clinical triage decision from that indicated by the stdECG. RESULTS: EASIDeltastdECG and PMLDeltastdECG were identical in 28%, whereas EASIDeltastdECG was more than PMLDeltastdECG in 35%, and PMLDeltastdECG was accurate (both time) than EASIDeltastdECG in 37% (P = .62). The physicians were more likely to change the level of patient care based on the EASI-derived ECGs compared with the paramedic ECGs; however, this difference was not statistically significant (P = .27), but this may only be caused by the small study population. CONCLUSIONS: There are similar differences from stdECG waveforms in EASI-derived ECGs and those acquired via paramedic-applied precordial electrodes using Mason-Likar limb lead configuration. Either method can be used as a substitute for monitoring, but neither should be considered equivalent to the stdECG for diagnostic purposes.

Adult↗
PubMed1995

Time-integrated blood lead concentration is a valid surrogate for estimating the cumulative lead dose assessed by tibial lead measurement.

The concentration of lead in tibia (Pb-T) was measured in vivo by a 109Cd K-shell X-ray fluorescence technique in 123 workers from a primary lead smelter (age: mean, 45 years; range, 30-61; duration of employment: mean, 20 years; range, 7-45). Their cumulative blood lead index (CBLI) was also calculated on the basis of the blood lead (Pb-B) records available from the company's medical files. Geometric mean for Pb-T was 49 micrograms Pb/g bone mineral (range, 15-167). The company's health surveillance programs, implemented since 1945, resulted in Pb-B values which rarely exceeded 70 micrograms Pb/dl whole blood. Pb-B at the time of Pb-T measurement averaged 31 micrograms Pb/dl (range, 6-62) and the geometric mean for CBLI amounted to 803 micrograms Pb/dl x year (range, 220-2130). Despite various assumptions and uncertainties inherent in the assessment of the cumulative lead dose through Pb-T measurement or CBLI calculation, the relation between both variables in the present lead smelter populations is very strong (rpearson = 0.80, P < 0.0001; age explained at the most 9.5% of the variance). The slope of the regression equation of log Pb-T vs log CBLI showed that a doubling of CBLI also corresponds to doubling of Pb-T. It may be concluded that a sound calculation of CBLI represents a valid surrogate for estimating the life time integrated dose of lead as assessed by the measurement of cortical bone lead (e.g., in tibia).

Adult↗
PubMed1995

Correlation between lead in plasma and other indicators of lead exposure among lead-exposed workers.

In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary delta-aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.

Adult↗
PubMed1996

Non-orebody sources are significant contributors to blood lead of some children with low to moderate lead exposure in a major lead mining community.

High precision lead isotope ratios in blood from 58 children aged 1-11 years from the Broken Hill lead mining community have been measured to determine the source and pathways of lead in their blood. Sources of lead are from the Pb-Zn-Ag orebody (lead), from paint and from petrol. Thirty-five of the 58 children (60%) had blood leads (PbB) > or = 0.72 micromol/l (15 microg/dl), the current level of 'personal exposure and source remediation/abatement' compared with a 'background' level of approximately 0.29 micromol/l (6 microg/dl), estimated from adult females who were generally mothers of the children. Six of 17 children aged 7 years or older, had PbBs > or = 0.72 micromol/l (15 microg/dl). Even though the orebody lead is the major contributor to PbB in Broken Hill children, of the 35 children whose PbB is > or = 0.72 microm/l (15 microg/dl), 12 (34%) have approximately 50% or more of their PbB derived from sources such as paint and petrol or both by isotopic identification. The identification of elevated PbB in older children is a concern, especially for females, as there is potential for release of endogenous lead during pregnancy and lactation.

Child↗
PubMed1991

Influences of thiamin on lead intoxication, lead deposition in tissues and lead hematological responses of Tilapia zillii.

1. Lead levels in the blood, kidney, liver, brain and muscle of fish receiving only lead were elevated markedly over the values of both controls and thiamin-treated fish. 2. No statistical difference was observed between the lead levels in bone samples of both fish receiving only lead and thiamin-treated fish. 3. In contrast to the fish receiving only lead the fish treated with thiamin appeared to be healthy and had no lead poisoning signs. 4. Over the period of study, hemoglobin content and red blood cell counts of fish receiving only lead showed significant decreases from the values of both controls and fish treated with thiamin. 5. Hematocrit values and white blood cell counts were uninfluenced by either lead exposure or thiamin treatment at all intervals. 6. The data suggest that thiamin can serve as a promising natural chelator to prevent fish mortality, not only in short term, but also in prolonged exposure.

Animals↗
PubMed2005

Effectiveness of lead-hazard control interventions on dust lead loadings: findings from the evaluation of the HUD Lead-Based Paint Hazard Control Grant Program.

From 1994 to 1999, the Evaluation of the US Department of Housing and Urban Development Lead-Based Paint Hazard Control Grant Program studied the intervention experiences of over 2800 homes in 11 states in the USA. Each interior intervention was categorized as (in order of increasing intensity) (a) cleaning/spot painting; (b) complete repainting; (c) complete repainting plus window treatments; (d) window abatement plus treatments to other components; (e) abatement of all lead-based paint hazards; or (f) abatement of all lead-based paint. Complete dust testing and environmental data were available for 1034 and 278 dwellings through 12 and 36 months postintervention, respectively. Strategies ranging from complete repainting to window abatement plus other treatments reduced geometric mean preintervention windowsill and floor dust lead loadings up to 36 months postintervention (reductions for complete repainting, from 16 to 5 microg/ft2 on floors and 182 to 88 microg/ft2 on sills; for window abatement plus other treatments, 27-8 microg/ft2 on floors and 570-124 microg/ft2 on sills). Full abatement reduced windowsill and floor loadings from baseline to 12 months postintervention [95-6 microg/ft2 on floors and 518-30 microg/ft2 on sills (data were not available for this strategy at 36 months)]. Window lead-hazard abatement was the most effective measure to reduce dust lead loadings on windows, but this treatment would need to be performed in conjunction with treatments to floors as well as exterior and soil treatments for the most effective control of dust lead on floors.

Dust↗
PubMed1992

Influence of the degree of exposure to lead on relations between alcohol consumption and the biological indices of lead exposure: epidemiological study in a lead acid battery factory.

Alcohol has been shown to interact with lead to influence haem biosynthesis. The aim of this study was to define the dependence of this interaction on the degree of exposure to lead. Exposure to alcohol was estimated by measurement of alcohol concentrations in a sample of urine collected during the morning (AlcUM) (0.82 (SD 4.36) mmol/l) and in a sample collected during the afternoon (AlcUA) (1.15 (SD 3.49) mmol/l). The biological monitoring of exposure to lead included measurements of blood lead (Pb-B) (1.82 (SD 0.72) mumol/l), urinary delta-aminolaevulinic acid (ALAU) (35.33 (SD 28.00) mumol/l; d = 1.015), and erythrocyte zinc-protoporphyrin (ZPP) (112.90 (SD 83.71) nmol/mmol Hb) concentrations. The study of the influence of the degree of occupational exposure to lead on relations between alcohol consumption and effects of the exposure to lead led to the consideration of two different groups--namely, mildly and strongly exposed subjects. In the first group, individual biological susceptibility seemed to play a preponderant part. In the second, the pool of lead present in the body seemed to be sufficiently important to mask the effects of individual susceptibility.

Alcohol Drinking↗
PubMed1993

Relationships between serial blood lead levels and exfoliated tooth dentin lead levels: models of tooth lead kinetics.

Because bones and permanent teeth accumulate lead, exfoliated deciduous teeth have been utilized as retrospective markers of cumulative exposure in epidemiological surveys. In this paper we describe four models of lead uptake by the coronal dentin of shed primary teeth, each with different assumptions and ramifications. Each model is characterized by different relationships between blood lead at several ages and tooth lead. Values observed in our cohort of normal Boston children are most compatible with models positing the largest lead contribution coming at older ages (i.e., closer to age at exfoliation). Characteristics of models incompatible with our data include (1) lead deposition only during initial calcification and (2) no loss or resorption of lead.

Dentin↗
PubMed1978

Comparative effects of feeding lead acetate and phospholipid-bound lead on blood and tissue lead concentrations in young and adult rats.

Two different forms of lead, lead acetate and phospholipid-bound lead, were fed to young and adult male rats for 10 weeks at the 300 ppm dietary level. Based on the lead concentrations found in selected tissues, our results indicate that the bioavailability of phospholipid-bound lead is similar to that of lead acetate at the 300 ppm level. Young rats had higher concentrations of lead in tissues than did adult rats.

Aging↗
PubMed1976

Effect of a short, heavy exposure to lead dust upon blood lead level, erythrocyte delta-aminolevulinic acid dehydratase activity and urinary excretion of lead delta-aminolevulinic acid coproporphyrin. Results of a 6-month follow-up of two male subjects.

During 1 h two healthy volunteers, not earlier exposed occupationally to lead, inhaled about 100 mg of lead as a mixture of lead oxides and lead sulfate. Maximum blood lead (PbB) concentrations of about 0.5 mg/1 and minimum blood cell delta-aminolevulinic acid dehydratase activities (ALAD) (6% of the preexposure values) were observed within 38 h after exposure. PbB and ALAD returned to preexposure levels after about 300 and 150 days. A highly significant correlation between ALAD and PbB was seen even at lead levels in the range 0.1-0.2 mg/1. Delta-aminolevulinic acid, coproporphyrin and lead in the urine (ALAU, CPU, and PbU, respectively) increased. The peak levels occurred after about 15 h for ALAU and CPU and after about 24 h for PbU. There was a very good correlation between log PbU and lin PbB. ALAU increased already at PbB levels of about 0.3 mg/1.

Adult↗