No abstract

With strong evidence coming to light for the toxicity of aluminium (Al), especially to the brain, investigation into the effects of inhalation of low concentrations of Al dust in animal models has become important. This study follows up previous observations on the effects of Al on the concentrations of essential metals in serum of workers exposed to inhalation of

Medicine, 33, 85-87. The in vitro effect of zinc on the inhibition of human 8-aminolevulinic acid dehydratase by lead. The antagonistic effect of zinc on inhibition of human aminolevulinic acid dehydratase (ALAD) by lead was examined in vitro. The phenomenon was studied at pH 6 5-7 5. Zinc and lead were added at concentrations ranging from physiological levels to levels far in excess of those expected in heavy industrial exposure. ALAD activity of normal blood assayed in the presence of zinc was unaffected by exogenous lead if the added zinc concentration was above 0 53 mmol/l blood. If zinc was added at 0 15 mmol/l blood, the total zinc concentration was approximately 0-28 mmol/l blood, or double the normal endogenous level, and was of the order found in heavy industrial exposure to zinc. In this case, ALAD assay values were appreciably raised and might have fallen into the normal range in spite of a dangerous total blood lead of over 0-0048 mmol/l. When zinc was added in vitro to blood from a worker with a blood lead level of 0 0043 mmol/l the ALAD values obtained were also raised and did not reflect the dangerous level of lead in the patient.Recent reports (Abdulla and Haeger-Aronsen, 1973;Meredith, Moore, and Goldberg, 1974)

An ethnic study of 175 individuals, comprising 65 black and 110 white South Africans, has shown a conclusive difference in the frequency of the M1(ala213) haplotype of α1‐antitrypsin (P < 0.00001). The M1(ala213) haplotype occurred more frequently in the black group. In the latter group, the frequency of the M1(ala213) haplotype was the same in both controls (0.55) and asthmatics (0.53). However, there was a significant difference in the frequencies (0.19 and 0.36) for the respective white groups (P < 0.01), the frequency of the M1(ala213) haplotype being much higher in the asthmatics. Apart from the above differences, there was also a difference in the elastase‐inhibitory capacities of the homozygote phenotypes M1(val213) vs M1(ala213) (P < 0.0001), this capacity being lower in the latter phenotype. We conclude that the occurrence of the M1(ala213) allele of α1‐antitrypsin differs in various ethnic groups and may play a role in asthma.

The concentrations of aluminium (Al) in serum and urine of 33 volunteers exposed to inhalation of A1203 dust at a concentration in the air of less than 1 mg Al/m3 were measured.These were compared with results from 20 normal subjects not exposed. The concentrations of copper (Cu), zinc (Zn), and total iron (Fe) in serum were also measured. The Al concentration in serum was significantly raised in the subjects exposed to dust, but Al concentrations in urine showed no significant difference from controls. This suggests a possible change in distribution of metals in the body tissues due to the presence of Al, with incomplete excretion of Al in the urine. This redistribution was selective, as the serum concentrations of Cu were conclusively decreased whereas the serum concentrations of Zn were conclusively increased. In this communication we report the effect of exposure to Al on concentrations of essential metals in foundry workers. We measured concentrations of Al in serum and urine. Iron (Fe), copper (Cu), and zinc (Zn) in the serum were also measured as well as lead (Pb) and cadmium (Cd) concentrations in whole blood. The Al exposed workers were compared with non-exposed subjects.Materials and methods Thirty three volunteers from the workers in two different foundries, who were exposed to aluminium dust and fumes, were investigated. They consisted of smelters, low and high pressure die casting operators, fettlers, and sand casters. All gave informed consent to the taking of their blood for this survey. A group of 20 normal, non-exposed subjects-was used for com-