Lead and lead poisoning in Early America: lead mines and lead poisoning.
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This article presents a method for the evaluation of cardiac depolarizations in a relatively short time with a minimum number of electrodes. With the negative electrode attached to the right infraclavicular region, voltage variations on the chest surface exhibit larger excursions than do the usual unipolar leads. Peak voltages of the PQRST waveforms measured on 12 normal patients by both methods were similar in polarity but were statistically significantly higher in the right infraclavicular leads. Data are presented on 21 normal patients, which show that digitized signals allow for an expanded time-scale leading to higher resolution of rate of change and onset and offset times. The digitized signals also more clearly define notches that distort the QRS complex. In 55 cardiac patients, the 12-lead unipolar electrocardiograms were visually compared to digitized electrocardiograms recorded by using the bipolar right infraclavicular leads. The authors suggest that RIC leads would be most useful in the design of a pocket-sized digitizing bipolar-lead electrocardiograph.
OBJECTIVES: This prospective study describes the impact of residential lead-based-paint hazard remediations on children with mildly elevated blood lead levels. METHODS: Changes in blood lead levels were observed following paint hazard remediation alone and in combination with soil abatement. RESULTS: After adjustment for the confounding variables paint hazard remediation alone was associated with a blood lead increase of 6.5 micrograms/dL (P = 0.5), and paint hazard remediation combined with soil abatement was associated with an increase of 0.9 microgram/dL (P = 36). CONCLUSIONS: Lead-based-paint hazard remediation as performed in this study, is not an effective secondary prevention strategy among children with mildly elevated blood lead levels.
The roles of environmental and behavioral factors in determining blood levels were studied in a cohort of young children living in an urban environment. The subjects were observed at 3-month intervals from birth to 24 months of age. Repeated measurements were made of the children's blood lead levels, environmental levels of lead in house dust, and in the dust found on the children's hands. A qualitative rating of the residence and of the socioeconomic status of the family was obtained. Interviews and direct observation of parent and child at home were used to evaluate various aspects of caretaker-child interactions. Data analysis consisted of a comparison of results obtained by simple correlational analysis, multiple regression analysis, and structural equations analysis. The results demonstrated that structural equation modeling offers a useful approach to unraveling the complex interactions present in the data set. In this preliminary analysis, the suspected relationship between the levels of lead in house dust and on hands and the blood lead level was clearly demonstrated. Furthermore, the analyses indicated an important interplay between environmental sources and social factors in the determination of hand lead and blood lead levels in very young children.
A survey of blood lead concentrations was undertaken with 368 dogs from a lead-mining (Broken Hill), lead-smelting (Port Pirie), urban (Adelaide) and rural island (Kangaroo Island) environment. Least squares mean blood lead concentrations differed significantly (p less than 0.001) between locations and were 1.05, 0.80, 0.38 and 0.32 mumol/L respectively; there were also significant differences between young (0.75) and older (0.52) dogs (p less than 0.01) and between male (0.71) and female (0.57) dogs (p less than 0.05). Approximately 14% of dogs from Broken Hill and 10% from Port Pirie had blood lead concentration in excess of 1.7 mumol/L. It is likely that a higher proportion of the dogs at Broken Hill and Port Pirie were asymptomatically suffering from the insidious effects of lead that has not been detected.
The diagnostic accuracy of ST elevation in lead III exceeding that of lead II (ratio III/II greater than 1) in the diagnosis of right ventricular infarction was investigated in 24 autopsied patients with inferior/posterior myocardial infarction on ECG. The results were compared with the diagnostic accuracy of ST elevation greater than or equal to 1 mm in right-chest leads V3R to V7R recorded in the same patients. All had left ventricular infarction documented at autopsy, and 17 (71%) had concomitant right ventricular involvement. The highest specificity (100%) and positive predictive value (100%) were calculated for the right-chest leads, whereas values for ratio III/II greater than 1 were 88% and 91%, respectively. The differences were not statistically significant. It is concluded that differences in ST elevation in leads III and II can be the basis for a diagnosis of right ventricular involvement in ECG-diagnosed inferior/posterior infarction. The diagnosis, however, may be achieved more easily with right-chest leads.
Calf pancreas microsomes were treated with 0.5-1% Triton X-100 and the resulting soluble enzyme preparation was incubated with GDP-D-[14C]mannose. The addition of synthetic Dol-PP derivative of the trisaccharide beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)GlcNAc stimulated the synthesis of labeled lipid-bound tetrasaccharide 50-100-fold. The labeled tetrasaccharide thus formed was identified as alpha-Man-(1 leads to 3)-beta-Man-(1 leads to 4)-beta-GlcNAc- (1 leads to 4)GlcNAc by its chromatographic properties and by its sensitivity to alpha-mannosidase and to endo-beta-N-acetylglucosaminidase D. The solubilized alpha-(1 leads to 3)mannosyltransferase did not require divalent cation and was active in the presence of 10 mM EDTA.
OBJECTIVES: The aim of the present study is to investigate whether lead (Pb) in urine (Pb-U) can be a valid surrogate of lead in blood (Pb-B), the traditional biomarker of exposure to lead in occupational health. METHODS: Blood and spot urine samples were collected from 258 workers of both sexes occupationally exposed to lead. The samples were analyzed for lead by graphite furnace atomic absorption spectrometry, and the correlation between Pb-B and Pb-U was examined by linear regression analysis before and after logarithmic conversion. RESULTS: The correlation coefficient (0.824; P < 0.01) was largest when the relationship between Pb-B and Pb-U was examined with 214 cases of one sex (i.e., men) after Pb-U was corrected for a specific gravity (1.016) of urine (Pb-Usg) and both Pb-B and Pb-Usg were converted to logarithms. The geometric means (GMs) of Pb-B and Pb-Usg for the 214 men were 489 microG/l and 81 microg/l, respectively. When Pb-Usg was assumed to be 100 microg/l in this set of correlations, the 95% confidence range of Pb-B for the group mean was narrow, i.e., 543-575 microg/l (with GM of 559 microg/l), whereas that for individual Pb-B values was as wide as 355-881 microg/l. CONCLUSIONS: The correlation of Pb-U with Pb-B among workers occupationally exposed to Pb was close enough to suggest that Pb-U may be a good alternative to Pb-B on a group basis, but not close enough to allow Pb-U to predict Pb-B on an individual basis.
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CaEDTA 20 mg/kg was administered weekly for 3.5 years after termination of occupational exposure to two lead workers. The diminution half-lives for lead in blood and urine lead mobilized by CaEDTA were 4.8 and 3.3 years respectively for subject 1 following 28 years exposure and 3.3 and 2.0 years respectively for subject 2 following 26 years exposure. The difference in the diminution rate between lead in blood and lead mobilized by CaEDTA was significant in subject 2 (p less than 0.05).
We report the case of a 69 year old patient, who underwent transvenous implantable cardioverter defibrillator (ICD) device change (Medtronic GEM VR 7227 Cx Active Can) because the ICD reached its replacement indicators. Preoperative chest X-ray and intraoperative defibrillation threshold tests and high voltage impedance did not show lead fracture of the five year old lead (Transvene 6936-65). At the second postoperative day the alarm of the newly implanted ICD device was activated because of high impedance in the painless lead impedance measurement (PLI) and the lead was replaced. The explanted lead showed a fracture detectable only by PLI.
Measurements of skeletal-lead content (by atomic absorption spectroscopy) were made for 16 individuals recovered from a Colonial (1670-1730) plantation cemetery in Virginia. Archaeological and historical evidence allowed the identification of two social groups (plantation proprietors and laborers) within this small population, each with vastly different estimated lifetime lead exposure, reflecting different living conditions. Measured bone-lead levels confirmed these differences. The character of plantation social organization proved a more important determinant of skeletal-lead content in the individuals studied than age, sex or race.
A subgroup of workers from a secondary lead smelter was defined to include those with blood lead levels not exceeding 80 microgram/100 ml and with no past history of elevated blood lead. Central nervous system symptoms (tiredness, sleeplessness, irritability, headache) were reported by 55% of the group and muscle and joint pain by 39%. Zinc protoporphyrin (ZPP) levels were elevated in 71% of cases. Low hemoglobin levels (less than 14 gm/100 ml) were found in more than a third of the workers. While BUN and creatinine were mostly in the normal range, there was nevertheless a correlation between ZPP and both BUN and creatinine. Reduced nerve-conduction velocities were present in 25% of the group; this was not significantly different from findings in a control group. The data indicate that a blood level of 80 microgram/100 ml is an inappropriate biological guide in the prevention of lead disease.
The threshold limit value (TLV) for lead (in Germany, the MAK value) is based on a certain blood lead concentration (in Germany BAT value = biological tolerance value for working materials) that is not to be exceeded; thereby a statistically significant association between air lead (PbA) and blood lead (PbB) is assumed. On the basis of a 10-year period of (1982-1991) biological and ambient monitoring of 134 battery factory staff and their workplaces, a PbA/PbB correlation with the regression equation PbB = 62.183 + 21.242 x Log 10 (PbA) (n = 1089, r = 0.274, P < 0.001) was calculated. These results are in line with those of several other investigations. The shape of the regression curve and the wide scattering of values led to the assumption that PbA values above the MAK value (0.1 mg/m3) do not necessarily result in increased PbB values. Similarly, PbA values lower than the MAK value do not guarantee PbB levels below the BAT value in every case. These observations are influenced by numerous confounders and intervening variables. It is concluded that lowering MAK values as a consequence of lowering BAT values is not mandatory.
Taking advantage of a prescribed reduction of the lead content of gasoline, the Athens Lead Experiment attempts to derive the fraction of blood lead due to gasoline lead in Athens subjects. The first results of the study, which is planned to continue until Spring 1986, are presented.
A twelve-channel machine was wired up in such a way that the same signals were recorded simultaneously via source leads, longitudinal bipolar leads and reference leads to an electrode at the base of the neck. This comparative study demonstrated that source leads do not provide a more accurate indication of the location of diffuse or extensive cerebral activity. On the contrary, in some cases we noted a decrease in the amplitude of the activities recorded, the suppression of certain components which were none the less present and even the appearance of a recording in phase opposition where there was no inversion of phases in the electrodes concerned.
Lead poses a serious environmental health risk to young children, causing such irreversible health effects as mental retardation, stunted growth, and hearing and visual impairment. Studies suggest that various sectors of the public, including children's caregivers, are not sufficiently concerned about this risk or knowledgeable about ways of minimizing it. Because newspapers are one of the primary ways members of the public learn about risks, the authors examined the characteristics and content of 152 newspaper articles on lead to determine when coverage occurred and what information was provided. Results revealed that newspapers most often covered lead as a local news story. Few articles identified children under six years of age as the most vulnerable group or provided important information on health effects, sources of exposure, or abatement methods. The authors' recommendations focus on helping environmental health professionals work with newspaper journalists to improve the information available to the public.
To assist in locating and quantifying fugitive emissions in a primary lead smelter, a "real time" lead-in-air analyzer has been developed. Dust is collected on paper tape filters and the lead analysed by X-ray fluorescence. The unit has been used successfully to assist in the implementation of an engineering control monitoring program.