Two standardized respiratory questionnaires in a Japanese version were given to 460 subjects randomly selected from male, middle-aged inhabitants of 15 villages in the Kashima district of Ibaraki Prefecture, Japan. One half of the men were given the questionnaire developed by the British Medical Research Council first and the questionnaire developed by the American Thoracic Society after an interval of about 2 weeks. The other half were given the questionnaires in reverse sequence. For questions with similar wording, the two questionnaires yielded very similar results, and in terms of the over-all prevalence of symptoms, no important differ-ences were found between the two questionnaires. However, there were not a few subjects whose individual responses to similar questions in the two questionnaires were not the same. The results seemed to be partly explained by unstable res-ponses of subjects who complained of a symptom to only a slight extent.
Recent data indicate that non-chelatable lead is converted to the che-latable form in the 24 h following intravenous administration of calcium disodium ethylenediamine tetraacetate (CaEDTA). To refine our previous model of the kinetics of lead mobilization in the light of those data, we simulated the daily mobilization yield of lead, zinc and copper in urine by CaEDTA and the sponta-neous urinary excretion of these metals during a 4-day course of intermittent CaEDTA injection as a function of the body burden of the chelatable metal (A), the proportion of the mobilization yield to A (k), the proportion of the sponta-neous urinary excretion to A(β), and the proportion of the chelatable metal con-verted from non-chelatable metal during 24 h following CaEDTA injection (a) to A (α). The values of A, a, k, β and α for each metal were calculated as a solution of the functional equation. We estimated that the body burden of chelatable lead ranged from 2.3 to 9.5 mg (mean 5.5 mg) in ten metal workers, employed on average for 13 years, with the whole blood lead concentrations of 39-64 (mean 49) μg/dl. Similarly, the body burden of chelatable zinc ranged from 0.2 to 16.6 (mean 0.9) g; and that of chelatable copper from 36 to 192 (mean 102) μg. The body burdens of chelatable lead and zinc thus estimated were significantly correlated with the whole blood lead and zinc concentrations. The 24 h mobilization yield of each metal in urine following administration of CaEDTA was approximately 39% of the chelatable body burden for lead, 0.1% for zinc and 33% for copper; 24 h spontaneous urinary excretions were approximately 2.5, 0.01 and 20% of the body burdens, respectively. An amount of non-chelatable lead corresponding to 21% of the body burden of chelatable lead was assumed to be converted from the nonchelatable to the chelatable form during the 24 h after CaEDTA injection; conversion rates for zinc and copper were almost negligible.
A method was developed for the sequential extraction of tetraethyllead (Et4Pb), triethyllead (Et3Pb+), diethyllead (Et2Pb2+) and inorganic lead (Pb2+) from one urine sample with methyl isobutyl ketone and the subsequent sequential determination of the respective species of lead by flame and flameless atomic absorption spectrometry. When 40 ml of a urine sample to which 2 μg of Pb of each of Et4Pb, Et3Pb+, Et2Pb2+ or Pb2+ had been experimentally added was assayed for the respective species of lead by flame atomic absorption spectrometry, ten repetitions of the assay gave a mean recovery rate of 98% for each of Et4Pb, Et3Pb+, and Et2Pb2+, and 99% for Pb2+, with a coefficient of variation of 2.0% for Et4Pb, 0.7% for Et3Pb+ and Pb2+, 2.6% for Et2Pb2+, and a detection limit of 4 μg of Pb/L for Et4Pb, 3 μg of Pb/L for Et3Pb+, and 5 μg of Pb/L for each of Et2Pb2+ and Pb2+. Examination of urine samples from a patient with tetraethyllead poisoning 22 days after exposure to the lead revealed that the total lead output was made up of about 51% Pb2+, about 43% Et2Pb2+, and about 6% Et3Pb+ but no Et4Pb. Administration of calcium ethylenediaminetetraacetic acid (Ca-EDTA) was followed by no increased urinary excretion of Et3Pb+ or Et2Pb2+.