Résumé
Inhibition of Hb biosynthesis in lead intoxicated subjects appears as a result of disorder in the interaction of Cu, Zn and Fe ions on delta-Am-inolevulinic acid dehydratase. [ALA-D]. Elevation of free serum copper and decrease of serum iron and zinc are the main cause of ALAD inhibition. Thus, it is safe to suggest that administration of Zn orally leads to replacement of cu from catalytic sites of this enzyme which is known as a zinc dependent enzyme
Sujets)
Humains , Mâle , Zinc/sang , Cuivre/sang , Fer/sang , 5-Aminolevulinate synthetase , Acide amino-lévulinique/urine , Porphobilinogene synthase , Plomb/sang , Transferrine , Céruloplasmine , Spectrophotométrie atomiqueRésumé
Changes in the hemoglobin-oxygen dissociation curve and the factors which influence its position were studied in lead poisoned subjects as compared to normal controls. Hemgolobin showed a lower than normal affinity for 02, and this could be considered as a protection against tissue anoxia. It is of interest to notice that 2,3 DPG and plasma inorganic phosphate were elevated with lead poisoning increment
Sujets)
Humains , Mâle , Exposition professionnelle , Plomb/sang , Gazométrie sanguine , Concentration en ions d'hydrogène , OxyhémoglobinesRésumé
In the present study the concentration, of lead particles and fumes in the working environment of a printing industry were throughly investigated. The blood lead, urinary lead and ALA of 106 exposed workers and 20 non-exposed workers, as a control group, were measured. Results showed that workers in the departments where lead materials are handled are mainly exposed to lead fumes which represent >80%of total lead exposure moreover, it was found that exposed to >20 micro/g/m[3] [8 hrs] atmospheric lead in both forms of respirable particles and vapour can result in high blood level. ALA was found to be a reliable indicator of lead effect. The present investigation points out that the TLV of 0.20 mg/m[3] is a non-realistic level since the exposure to atmospheric lead in a range between 20-37 micro g/m3 results in a high blood lead and subsquently a higher level of ALA in urine. Consequently, it is suggested to lower the TLV for lead exposure especially where lead fumes exist. Conclusions and special recommendations were given