Lead content of brain tissue in diffuse neurofibrillary tangles with calcification (DNTC): the possibility of lead neurotoxicity.

Diffuse neurofibrillary tangles with calcification (DNTC) is a form of presenile dementia, characterized pathologically by fronto-temporal atrophy with neurofibrillary tangles (NFTs), neuropil threads and Fahr-type calcification, in which no senile plaques are observed. As already noted, chronic exposure to lead (Pb) might be one of the etiological factors of Fahr-type calcification. Until now, there have been no reports in which Pb concentration has been quantified in DNTC brains. We examined the concentration of Pb in fresh-frozen brain tissue and in 10% formalin-fixed brain tissue from six cases of DNTC, four cases of Alzheimer's disease, and in nine non-demented elderly controls by flameless atomic absorption spectrometry, and demonstrated a high concentration of Pb in DNTC brains. Although it remains unclear how these findings are related to the formation of NFTs, they suggest that Pb neurotoxicity may be involved in the pathogenesis of DNTC.

Simultaneous determination of the urinary metabolites of toluene, xylene and styrene using high-performance capillary electrophoresis. Comparison with high-performance liquid chromatography.

A simple and rapid method using high-performance capillary electrophoresis (HPCE) for the simultaneous determination of the urinary metabolites of toluene, xylene and styrene, plus creatinine and uric acid in human urine specimens and standard solutions is described. The compounds were well separated from each other on a fused-silica capillary utilizing a 20 mM sodium tetraborate buffer (pH 9.65) with 15 mM beta-cyclodextrin and UV detection at 200 and 225 nm. The total analysis time was less than 6 min per sample. The capillary zone electrophoresis (CZE) method shows a good correlation with the high-performance liquid chromatography (HPLC) method with respect to urinary hippuric acid concentrations in the urine specimens of subjects exposed to the vapors of a solvent mixture of toluene and xylene. In comparing these two techniques, HPCE was found to be superior to HPLC because the analysis time is shorter, and the separation of m-MHA and p-MHA takes a long time with HPLC.

Reduced serum levels of ALT and GGT and high carbohydrate intake among workers exposed to toluene below the threshold limit values.

We have found decreased serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) levels in human males exposed to toluene at low levels, suggesting that toluene exposure or related factors in lifestyles were likely to have lowering effects on serum ALT and GGT activities between toluene-exposed and the control subjects. The present study was attempted to investigate whether there is any difference in nutrient intakes between the two groups. Biochemical results were also analysed together with nutrient intakes. In agreement with our previous reports, the present data also provided significant evidence of lowered serum ALT and GGT activities in toluene-exposed males after age matching (p < 0.05). Energy intakes from carbohydrate, fat and protein were 64.6%, 22.5% and 12.9% in the toluene-exposed group and 62.0% (p < 0.05), 24.8% (p < 0.05) and 13.2%, respectively, in the controls. Multiple regression analysis indicated that carbohydrate, protein and energy intakes are significantly associated with toluene exposure. No significant differences in alcohol consumption, tobacco use, work intensities and physical activities were found between the two groups. The present results suggest that the toluene exposure at levels generally considered to be safe, probably have some biological effects on the liver and related organs.