Urinary ALA Levels Research Articles

Association between a Polymorphism of Aminolevulinate Dehydrogenase (ALAD) Gene and Blood Lead Levels in Japanese Subjects

This cross-sectional study investigated the relationship between the aminolevulinate dehydrogenase (ALAD) genotype and blood lead levels among 101 Japanese workers. Blood lead concentration measurement, biomarkers, and genotyping were performed. The minor allele frequency (MAF) for ALAD (ALAD2) was 0.08. Although the blood lead level in the subjects with heterozygous GC genotype was significantly higher than those with homozygous GG genotype, there were no significant differences for hemoglobin, hematocrit, serum and urinary ALA levels among genotypes. ALAD2 genotype was significantly associated with the blood lead concentration, even in the environmental lead exposed subjects. Further confirmation with a large sample size is needed.

Decrease of hepatic δ-aminolevulinate dehydratase activity in an animal model of fatigue

Fatigue can be defined physiologically as inability to maintain the expected power output. At present, no standard of fatigue are yet available. In order to find biomarkers of fatigue, we investigated the level of δ-aminolevulinic acid (ALA), the first intermediate metabolite in the heme biosynthetic pathway, in the plasma and urine of an animal model of fatigue. To prepare fatigued animals, we kept rats for 5 days in a cage filled with water to a height of 1.5 cm. As a result, the plasma and urinary ALA levels were increased in the fatigued animals as compared with those in the control animals. One day after the rats had been returned to their normal cages, these increased levels were restored to the control ones. We also examined the activity of the enzyme ALA dehydratase (ALAD), which is the second enzyme in the heme biosynthetic pathway, and ALAD gene expression during the fatigue and its recovery sessions. The ALAD activity, as well as its gene expression, in the liver of the fatigued animals was decreased as compared with those of the control animals. Both activity and gene expression of ALAD were recovered to their respective control levels after the rats had been allowed to rest in their normal cages for 1 day. Furthermore, the activity of ALA synthase (ALAS), the rate-limiting enzyme in the heme biosynthesis, in the liver was increased after the fatigue session for 5 days. Although this level of increase in the plasma concentration of ALA may not induce fatigue, increase in plasma and urinary ALA levels can be biomarkers of fatigue.

Tetramethyl lead absorption: a report of human exposure to a high level of tetramethyl lead.

Accidental human exposure to a high level of tetramethyl lead is described. Tetramethyl lead is blended with petrol as an antiknock agent, and it has similar physical properties to tetraethyl lead. The patient had high levels of lead in urine, averaging 4-75 mumol (983 mug) daily for the first four days after exposure and he continued to have raised levels of urinary lead for six months. He had no symptoms or physical signs of lead poisoning and comparisons are made between this case and previously reported cases of poisoning by tetraethyl lead. In the cases of tetraethyl lead poisoning all the patients had symptoms, some severe, yet in no instance did the urinary lead levels approach those described in this patient. The effects of chelation therapy with calcium disodium versenate are discussed and the results are similar to those found in tetraethyl lead poisoning. Blood lead levels of up to 3-91 mumol/l (81 mug/100 g) occurred but these levels were not raised commensurate with the urinary lead output. The levels of deltaaminolaevulinic acid (ALA) in the urine were not significantly raised and this report shows that the urinary lead levels give a better guide to the degree of absorption of tetramethyl lead compared with the blood lead or urinary ALA levels. The report illustrates that tetramethyl lead is less toxic to man than tetraethyl lead.

Biochemical assessment of inorganic lead hazards

Today, industrial workers exposed to lead rarely suffer from lead poisoning but they are at risk and should be screened regularly to evaluate their lead absorption. Three groups of workers exposed to an inorganic lead compound and a reference group not so expcsed were studied. Absorption of lead was measured by serial blood lead estimations by atcmic absorption. Toxicity was assessed by urinary ALA levels, a porphyrin screen with a quantitative coproporphyrin if necessary, haemoglobin levels and stippled cell counts. Marked differences between the groups were shown. All the workers were clinically well but many of one group showed obvious biochemical abnormalities. At the levels of exposure encountered, evaluation of tests of toxicity against lead absorbed, showed urinary ALA to give the best correlation, while haemoglobin and stippled cells were of little value. Lead levels remained stable over 2-3 yr. in many workers. Changes of 20μg./100 ml. or more were related to changes in exposure. Today, industrial workers exposed to lead rarely suffer from lead poisoning but they are at risk and should be screened regularly to evaluate their lead absorption. Three groups of workers exposed to an inorganic lead compound and a reference group not so expcsed were studied. Absorption of lead was measured by serial blood lead estimations by atcmic absorption. Toxicity was assessed by urinary ALA levels, a porphyrin screen with a quantitative coproporphyrin if necessary, haemoglobin levels and stippled cell counts. Marked differences between the groups were shown. All the workers were clinically well but many of one group showed obvious biochemical abnormalities. At the levels of exposure encountered, evaluation of tests of toxicity against lead absorbed, showed urinary ALA to give the best correlation, while haemoglobin and stippled cells were of little value. Lead levels remained stable over 2-3 yr. in many workers. Changes of 20μg./100 ml. or more were related to changes in exposure.

Urinary delta-aminolevulinic acid (ALA) levels in lead poisoning. II. Correlation of ALA values with clinical findings in 250 children with suspected lead ingestion.

The method for the determination of urinary delta-aminolevulinic acid (ALA) from random urine samples has been modified utilizing a dual disposable chromatographic column unit prefilled with resin that can be conveniently held in a support rack over a drain tray. The present procedure now permits one individual to perform as many as 1,000 analyses of urinary ALA in a normal working week. A single-blind evaluation was made of the laboratory findings and clinical impression of increased lead exposure versus the urinary ALA levels obtained in each of 250 children suspected of lead ingestion. St was found that the incidence of a correct correlation between urinary ALA and the clinical diagnosis of increased lead exposure was 91%. None of the other laboratory tests studied had a comparable degree of accuracy for the detection of early lead exposure.