0141739 



affects all major body organs and has been found concentrated in 

 kidneys, liver, spleen, heart and brain. Circulating lead 

 combines with erythrocytes and results in increased fragility of 

 red blood cells and their subsequent premature destruction. Lead 

 also depresses bone marrow and as a result fewer red blood cells 

 are produced. The above effects of blood result in the develop- 

 ment of microcytic hypochronic anemia in some animals species. 

 Lead causes rupture of lysosomes and release of acid phosphatase 

 that is required for energy production and protein synthesis. 

 Lead disrupts heme synthesis by interfering with several enzymes 

 and blocks metabolism of aminolevulinic acid which causes abnor- 

 mally large amounts of deltaminolevulinic acid to appear in plasma 

 and urine. Chronic lead poisoning causes degeneration of kidney 

 and liver tissues with necrosis of the renal tubule cells. Acute 

 poisoning produces necrosis of the gastrointestinal mucosa. The 

 central nervous system is affected by decreased blood supply due 

 to capillary damage which produces edema or collapse of small 

 arteries. Extensive brain lesions have been noted in both chronic 

 and acute lead poisoning in cattle (Christian and Tryphonas 1971). 

 These lesions involve the cerebral cortex, thalamus, hypothalamus, 

 medulla oblongata and proximal cervical spinal cord. Pharyngeal 

 or buccal paralysis in cattle and laryngeal and pharyngeal 

 paralysis in horses may be produced by damage to either cranial 

 nerves or the brain stem nuclei. Incoordination and degeneration 

 of muscle control occurs through segmental demyel ination of 

 peripheral nerves. 



Lead has been shown to adversely affect reproduction in 

 several animal species, including humans. Sheep grazing in lead 

 mining areas have exhibited high rates of abortions and failures 

 to conceive. Pregnant goats on lead-supplemented diets (lead 

 acetate, 50 to 6,400 mg Pb/kg/day) aborted 6 to 8 days after 

 starting the lead diets (Dollahite et al. 1975). There is 

 evidence that lead can cross the placenta and affect fetal 

 development (Barltrop 1969). 



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