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Hg Levels (hg + level)

Distribution by Scientific Domains

Life Sciences	71%
Medical Sciences	28%

Selected Abstracts

Pyruvate Preserves Neutrophilic Superoxide Production in Acidic, High Glucose-Enriched Peritoneal Dialysis Solutions

ARTIFICIAL ORGANS, Issue 3 2003
Yi Tai Wu
Abstract: Aim: To investigate effects of pyruvate (Py)-based peritoneal dialysis solutions (P-PDS) on neutrophilic superoxide (O2,) production against high glucose (HG) concentrations at acidic or physiologic pH value, and explore potential mechanisms. Methods: Human neutrophils were incubated with both dl -lactate (La, 40 mM)-based PDS (L-PDS) and equimolar P-PDS at various pH and HG levels, respectively. Hanks' balanced salt solution (HBSS) served as controls. O2, generation was determined by the reduction of ferricytochrome c. Results: Acidic pH and high La induced acute and substantial inhibitions of O2, production. HG in both PDS and HBSS resulted in a suppression of O2, in a dose-dependent manner. P-PDS generated near twofold O2, formation of L-PDS counterparts at various pH and HG levels. P-PDS with HG produced significantly more O2, than Py-free HBSS counterparts. Conclusions: Py in PDS effectively protected neutrophils from HG-induced inhibition of O2, production, even at a physiological pH. The Py cytoprotection may be associated with the preservation of carbohydrate metabolic pathways in addition to its alkalization. [source]

Bioenergetic and pharmacokinetic model for exposure of common loon (Gavia Immer) chicks to methylmercury

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2007
William H. Karasov
Abstract A bioenergetics model was used to predict food intake of common loon (Gavia immer) chicks as a function of body mass during development, and a pharmacokinetics model, based on first-order kinetics in a single compartment, was used to predict blood Hg level as a function of food intake rate, food Hg content, body mass, and Hg absorption and elimination. Predictions were tested in captive growing chicks fed trout (Salmo gairdneri) with average MeHg concentrations of 0.02 (control), 0.4, and 1.2 ,g/g wet mass (delivered as CH3HgCl). Predicted food intake matched observed intake through 50 d of age but then exceeded observed intake by an amount that grew progressively larger with age, reaching a significant overestimate of 28% by the end of the trial. Respiration in older, nongrowing birds probably was overestimated by using rates measured in younger, growing birds. Close agreement was found between simulations and measured blood Hg, which varied significantly with dietary Hg and age. Although chicks may hatch with different blood Hg levels, their blood level is determined mainly by dietary Hg level beyond approximately two weeks of age. The model also may be useful for predicting Hg levels in adults and in the eggs that they lay, but its accuracy in both chicks and adults needs to be tested in free-living birds. [source]

Synanthropic primates in Asia: Potential sentinels for environmental toxins

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2010
Gregory Engel
Abstract Macaques are similar to humans both physiologically and behaviorally. In South and Southeast Asia they are also synanthropic, ecologically associated with humans. Synanthropy with humans raises the possibility that macaques come into contact with anthropogenic toxicants, such as lead and mercury, and might be appropriate sentinels for human exposures to certain toxic materials. We measured lead (Pb) and mercury (Hg) levels and characterized the stable isotopic compositions of ,15N and ,13C in hair from three groups of free-ranging macaques at the Swoyambhu temple in Kathmandhu, Nepal, an urban population that has abundant contact with humans. Hair lead levels were significantly higher among young macaques and differed among the three groups of macaques that were sampled. Hair Hg levels were low. No statistical association was found between stable isotopic compositions (,15N and ,13C) and Pb and Hg levels. Our data did not find evidence that lead levels were associated with diet. We conclude that, in this population of macaques, behavioral and/or physiologic factors may play a significant role in determining exposure to lead. Chemical analysis of hair is a promising, noninvasive technique for determining exposure to toxic elements in free-ranging nonhuman primates. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source]

Mercury Exposure Increases Circulating Net Matrix Metalloproteinase (MMP)-2 and MMP-9 Activities

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2009
Anna L. B. Jacob-Ferreira
We investigated whether there is an association between the circulating levels of MMP-2, MMP-9, their endogenous inhibitors (the tissue inhibitors of metalloproteinases; TIMPs) and the circulating Hg levels in 159 subjects environmentally exposed to Hg. Blood and plasma Hg were determined by inductively coupled plasma-mass spectrometry (ICP-MS). MMP and TIMP concentrations were measured in plasma samples by gelatin zymography and ELISA respectively. Thiobarbituric acid-reactive species (TBARS) were measured in plasma to assess oxidative stress. Selenium (Se) levels were determined by ICP-MS because it is an antioxidant. The relations between bioindicators of Hg and the metalloproteinases levels were examined using multivariate regression models. While we found no relation between blood or plasma Hg and MMP-9, plasma Hg levels were negatively associated with TIMP-1 and TIMP-2 levels, and thereby with increasing MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios, thus indicating a positive association between plasma Hg and circulating net MMP-9 and MMP-2 activities. These findings provide a new insight into the possible biological mechanisms of Hg toxicity, particularly in cardiovascular diseases. [source]