Zinc Case Studies

Include below part also with zinc attenuation

Zinc is known to prevent and treat the intoxication of lead which often proves more effective along with the combination of methionine or thiamine (Flora et al., 1989; 1991). Supplementation of zinc simultaneously with methionine or thiamine helps effectively reduce urinary excretion of ALA and the lead induced ALAD activity in the blood. It is suggested from such studies that the combination therapy including the essential nutrient elements and vitamins concurrently with exposure to lead could be more effective than treating the lead toxicity after exposure. This helps to reduce the absorption of lead in the gastrointestinal tract. Thus it can be attributed that zinc help to reduce the lead absorption

Developing children who need higher levels of nutrients than adults are more vulnerable to such manifestations. Studies show that lead toxicity can cause its effects on the CNS even at the blood lead concentration of 0.48 and 0.7pmol/litre [need REF]. In United States, there are over one million children having blood lead levels in this range (ATSDR, 1988; NRC, 1993). With enhanced exposure the manifestations of lead on CNS, among adult subpopulation are associated with alteration in the physiological conditions like lactation, pregnancy, bone resorption and

Sunderman and Barber first suggested that probably lead is bound to many of the zinc binding nuclear proteins and thus inhabit several functions and potentially disregulate gene expression [77]. Appropriate conformational structure has been well demonstrated and conferred to as the critical role of zinc. These structures has been well demonstrated for such zinc finger loop proteins, including transcription regulators [78,79]. It has been demonstrated through spectroscopy, NMR, and cellular dichroism analysis that zinc is displaced by lead which cause conformational change in the human protamines (HP2) (a histone like DNA binding protein unique to sperm) [75,76,80]. In this protein lead binds to sulfhydryl and non sulfhydryl sites and displaces zinc. Reduction in the binding of this protein to DNA consensus sequences were resulted due to conformational changes. Subsequent binding of HP2 to consensus sequences in DNA is significantly reduced when it is bound to lead [75]. Further there are other reports on similar effects of lead on other zinc containing DNA binding proteins [72,73, 76]. An enhancement of oxidative DNA base damage at purines and pyrimidines as well as double standard DNA breakage was reported, when zinc in the HP2 is replaced by nickel or copper [84]. Alterations in the interaction between DNA and nuclear transcription factors