Differential persistence of chromosomal damage induced in resting rat-liver cells by X-rays and 4.2-MeV neutrons

The association of DNA damage to concentrations of mercury and radiocesium in largemouth bass

“…Although previous studies have suggested a relationship between mercury concentration and DNA damage in liver tissue [9], in this study only radiocesium concentration and body condition explain a significant portion of the variation in damage for liver when data for all localities are used. It would appear that both mercury concentration and body condition directly affect the amount of DNA damage in blood (the effect of radiocesium is only through its interaction with these two factors) Interestingly, the relationship between %DS DNA in blood and body condition is negative, implymg that an increase in condition would lead to greater DNA damage Given the state of our knowledge concerning the cellular physiology of these tissues in fish, explanations for the differences in responses to toxicants are largely speculative Liver and gill tissues tend to be persistent, and red blood cells are generally considered to be terminal (however, see [40]) Because liver filters toxicants from the blood, one may expect this tissue to have very efficient DNA repair enzymes However, previous studies have demonstrated persistent DNA damage in rat liver [41,42] Because red blood cells are not actively producing proteins, they may have minimal DNA repair capabilities Gill cells, which are primarily for exchange of ions and gases, may have an intermediate ability to repair DNA damage This scenario is consistent with the general observation that damage is greatest in blood and least in liver However, the odd results for blood from Pond B and Pond C do not fit well with this speculative scenario…”