Early signs of lead-exposure. A comparative study of laboratory tests

Previous work has shown that urinary lead, coproporphyrin (CP), and δ-aminolaevulinic acid (ALA) are closely related after exposure to lead. We have confirmed the relationship in 50 automobile workers with different exposures, and have also estimated porphobilinogen (PBG) levels. There was some evidence that a raised ALA level gave an earlier sign of lead absorption than a raised CP level. ALA-dehydratase activity (converting ALA to PBG) was greatly reduced by exposure, on the average to 20% of normal. This reduction in activity was strongly correlated with the increases in urinary lead, CP, and ALA and is the most sensitive test of exposure to lead. A weak correlation was found between the number of coarsely stippled cells, or the basophilic quotient, and the urinary levels of lead, CP, and ALA. In addition, the serum aspartate aminotransferase (SGOT) and serum alanine aminotransferase (SGPT) levels were estimated and were not affected by exposure to lead. The serum protein patterns and haemoglobin levels were also unaffected.

Studies on azide, caeruloplasmin and copper in relation to Wilson's disease

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Blood transaminase activities in vitamin B6 deficiency: effect of depletion and repletion on the erythrocyte enzymes

To assess the usefulness of the erythrocyte transaminases, glutamic–oxaloacetic and glutamic–pyruvic, in the evaluation of vitamin B6 nutritional status, the response of these enzymes to repletion following 1, 4, and 10 weeks of vitamin B6 depletion was compared with that of the plasma and liver transaminases in the rat. The responses of the erythrocyte enzymes reflected the state of vitamin B6 nutrition most accurately and, unlike the plasma and liver transaminases, were not affected by other factors. Repletion produced a rapid response in the erythrocyte enzymes; however, restoration of control levels appeared to depend on red cell turnover, particularly after prolonged depletion periods. This finding suggests that the apoenzyme, as well as the coenzyme, is depleted during vitamin B6 deficiency.