Mercury exists naturally and as a man-made contaminant. The release of processed mercury can lead to a progressive increase in the amount of atmospheric mercury, which enters the atmospheric-soil-water distribution cycles where it can remain in circulation for years. Mercury poisoning is the result of exposure to mercury or mercury compounds resulting in various toxic effects depend on its chemical form and route of exposure. The major route of human exposure to methylmercury (MeHg) is largely through eating contaminated fish, seafood, and wildlife which have been exposed to mercury through ingestion of contaminated lower organisms. MeHg toxicity is associated with nervous system damage in adults and impaired neurological development in infants and children. Ingested mercury may undergo bioaccumulation leading to progressive increases in body burdens. This review addresses the systemic pathophysiology of individual organ systems associated with mercury poisoning. Mercury has profound cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive, and embryonic toxicological effects.

These results suggest that acetaminophen may be useful for the treatment of age-associated hyperglycemia.

Here, we determine the influence of aging on multiple markers of oxidative stress in the aorta of adult (6-month), aged (30-month) and very aged (36-month) Fischer 344/NNiaHSdxBrown Norway/BiNia (F344/NxBN) rats. Compared to adults, increases in as determined by oxidation of hydroethidine (HE) to ethidium (Et) were increased 79.7+/-7.0% in 36-month aortae and this finding was highly correlated with increases in medal thickness (r=0.773, p<0.01) and total protein nitration (r=0.706, p<0.01) but not Ki67, a marker for cell proliferation. Regression analysis showed that increases in aortic superoxide anion (O.-2) with aging were significantly correlated with changes in the expression and/or regulation of proteins involved in metabolic (AMPK-alpha), signaling (mitogen activated protein kinases (MAPKs) along with c-Src), apoptotic (Bax, Bcl-2, Traf-2) and transcriptional (NF-kappaB) activities. These results suggest that the aging F344/NxBN aorta may be highly suited for unraveling the molecular events that lead to age-associated alterations in aortic oxidative stress.

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It is thought that aging in rats and humans is associated with increases in iron accumulation and cell apoptosis. Here, we examine the relationship between cardiac iron levels and apoptosis in aged F344XBN rats that had been treated with an oral iron chelator (Deferasirox; 100 mg/kg body weight) on alternate days for 6 months. Compared to adult animals (6 month), cardiac iron (+72%), liver iron (+87%), ferritin light chain (+59%), divalent metal transporter-1 (+56%) and the number of TdT-mediated dUTP nick end labeling (TUNEL) positive cells (4.3 fold increase) were higher in 33-month-old animals (P < 0.05). Deferasirox treatment decreased cardiac iron levels by 37% (P < 0.05), and this was associated with decreases in the number of TUNEL-positive cells. Age-associated increases in cell death were coupled with increases in Bax to Bcl-2 ratio, and the amount of Bad, full-length caspase-3, and cleaved caspase-3. Deferasirox treatment decreased the Bax to Bcl-2 ratio by 17% (P < 0.05) and the amount of Bad, full-length caspase-3, cleaved caspase-3 (19 kDa), and cleaved caspase-3 (17 kDa) by 41, 16, 22, and 37%, respectively (P < 0.05). Taken together, these data suggest that deferasirox may be effective in diminishing age-associated iron accumulation and cardiac apoptosis in the F344XBN rat model.

There is a growing need for pharmacological agents to manage cardiovascular disease in the rapidly growing elderly population. Here, we determine if acetaminophen is efficacious in decreasing age-related increases in cardiac reactive oxygen species (ROS) and apoptosis in aging Fischer 344 X Brown Norway rats. Compared to 6-month control animals, indices of oxidative (superoxide anion [O2( *-)] and 4-hydroxy-2-nonenal [4-HNE]) and nitrosative (protein nitrotyrosylation) stress were markedly increased in 33-month-old rat hearts. 33-month animals that had been treated with acetaminophen (30 mg/kg/day p.o. for 6 months) exhibited diminished age-related increases in cardiac ROS levels and TUNEL positive nuclei and these changes were accompanied by improvements in the Bax/Bcl2 ratio, diminished evidence of caspase-3 activation and increased phosphorylation of protein kinase B, ERK1/2, p70S6K and GSK-3beta. Taken together these results suggests that acetaminophen may attenuate the age-associated increases in the cardiomyocyte apoptosis, possibly via diminishing age associated elevation in ROS production.

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A report linking human polycystic ovary with increased exposure to environmental DDT (Heinrichs et al. 1971) prompted the present study comparing effects of PCB and DDT or their combination on reproduction in female rats under more realistic conditions with respect to level (75 and 150 ppm), route of administration (dietary contaminant), and period of exposure (8 and 36 weeks). Evaluation of estrous cycle length, mating frequency, number and size of litters; as well as plasma levels of DDT, PCB, progesterone (P), and 17 alpha=hydroxyprogesterone (17 alpha=OH-P), permitted comparison of short and long term reproductive changes from ingestion of two levels of DDT and/or PCB. PCB reduced plasma progesterone (p less than .01) while plasma 17alpha OH-P was unchanged by PCB or DDT. High DDT and PCB abolished reproduction. Histologically, distinct ovarian stromal changes accompanied 150 ppm of PCB, while increased numbers of more prominent follicular cysts were evident with 150 ppm of DDT. Although DDT and PCB generally reduced or abolished litter production, no treatment tested significantly altered litter size. Long term chronic ingestion of more realistic levels of technical DDT (85% p,p', 15% o,p'-DDT) in these studies did not lead to polycystic ovaries in adult rats comparable to those reported following i.v. administration of pure o,p'-DDT to immature rats. Plasma DDT levels above 800 ppb are clearly detrimental to reproduction, while levels below 500 ppb had lettle effect. Finally, we present the first evidence reported to our knowledge demonstrating that prolonged ingestion of PCB (150 ppm) markedly reduces reproduction (p less than .05) accompanied by significantly reduced progesterone in plasma (p less than .01) as well as by histologically characteristic ovarian stromal changes not seen with DDT alone.