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OAR Box 1128 

Prepped by Ollie Stewart 

Document Number: 

90) 11-1-419 

Docket Number: 

A-83-22 

Printed 4/21/2008 11:07:14 AM Sheet 90 of 198 
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NON-RECOVERY OF USD-INDUCED CHANGES OF VISUAL EVOKED POTENTIALS IM RATS 

G.WINNEKE (Medizinisches Institut fiir Urtwelthygiene an der Universitat DUsseldorf, DUsseldorf, W-Germany 

Airplitude-depression of visual evoked brain-potentials (VEP) was found in rats 

at blood lead-levels (PbB) in excess of 30 pg/dl (Winneke, Act.Nerv.Sup.,1980, 

in press). The present study was designed t o test the degree of recovery of 

this effect. Three groups of male Wistar-rats (n=10) were studied: A controlgroup (A), a 2nd group (B) with only maternal Fb-exposure (2200 ppm as leadacetate in the diet) until weaning a t 21 d, and a 3rd group (C) with additional 

postnatal dietary Pb-exposure until testing at about 12 months of age. These 

diets are known to give ris e to steady-state PbBs of about 40 ug/dl and corresponding brain lead-levels. Flash-evoked braih-potentials were recorded frcm 

striat e cortex via'epidural electrodes during sleep-states. Results: (1) Marked 

amplitude-depression was found in group C-animals as canpared to controls,thus 

confirming our ealie r findings; (2) the degree of amplitude-depression was as 

pronounced in group B-aniwalh a s In thos e o f group C. Conclusions: 

Lead-Induced modifications of VEP-amplitudes, indicating damage 

to the visual system, do hot seem to recover, if the exposure takes 

place during the early stages of CNS-development; the underlying 

dysfunction appears to be longlasting if not irreversible . 

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METHYLMERCURY POISONING IH THE SUCKLING INFANT 

L.AMIH-ZAKI1, S.B. ELHASSANI1. ?; M.A.MAJEED1; T.W.CLARKSON2; R.A.DOHERTY2; 

M.R. GREENWOOD2 »'•;

 1 University of Baghdad, Iraq; 2University of Rochester ,H.Y., 

USA;

 3Spartanburg General Hospital,S.C.,USA; ''Xerox Corp., Rochester, N.Y.,USA 

In a five year logitudinal study of Mothers and Infants exposed to methylmercury during the Iraq epidemic of 1972, the frequencies of signs and symptoms 

exhibited by the mothers were typical of methylmercury poisoning. When blood 

concentrations of mercury are corrected to March 1, 1972, mothers with the 

nost sevete signs and symptoms had an average blood mercury concentration 

significantly higher, p<.01, than either the milder or asymptomatic groups. 

Analytical data indicate that the predominant route of exposure for the infant 

was through breast milk in which approximately 60% of total mercury was 

determined, by cold vapor atomic absorption, to be organic mercury. Abnormal 

neurological signs in these infants became more obvious with time; hyperreflexia was observed in D of 22 infants at first examination, and in 17 of 22 

at second examination. Delayed motor development became evident at the second 

and third examinations. The frequency of pathological reflexes, delayed motor 

developmental milestones and nocturnal enuresis were all so high as to be 

considered significant even in the absence of a controlled study. There was 

no increase in mortality as compared to a control group. 

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