Rick J. Jansen, Maria Argos, Tong Lin, Jiabei Li et al.
BACKGROUND: Exposure to inorganic arsenic (iAs), a class I carcinogen, affects several hundred million people worldwide. Once absorbed, iAs is converted to monomethylated (MMA) and then dimethylated forms (DMA), with methylation facilitating urinary excretion. The abundance of each species in urine ...
Maria Argos, Lin Chen, Farzana Jasmine, Tong Lin et al.
BACKGROUND: Inorganic arsenic is one of the most common naturally occurring contaminants found in the environment. Arsenic is associated with a number of health outcomes, with epigenetic modification suggested as a potential mechanism of toxicity. OBJECTIVE: Among a sample of 400 adult participants,...
Megan N. Hall, Megan M. Niedzwiecki, Xinhua Liu, Kristin N. Harper et al.
BACKGROUND: In vitro and rodent studies have shown that arsenic (As) exposure can deplete glutathione (GSH) and induce oxidative stress. GSH is the primary intracellular antioxidant; it donates an electron to reactive oxygen species, thus producing glutathione disulfide (GSSG). Cysteine (Cys) and cy...
Megan M. Niedzwiecki, Megan N. Hall, Xinhua Liu, Julie Oka et al.
Background: Several studies employing cell culture and animal models have suggested that arsenic (As) exposure induces global DNA hypomethylation. However, As has been associated with global DNA hypermethylation in human study populations. We hypothesized that this discrepancy may reflect a nonlinea...
Caitlin G. Howe, Megan M. Niedzwiecki, Megan N. Hall, Xinhua Liu et al.
Chronic exposure to inorganic arsenic (InAs) through drinking water is a major problem worldwide. InAs undergoes hepatic methylation to form mono- and dimethyl arsenical species (MMA and DMA, respectively), facilitating arsenic elimination. Both reactions are catalyzed by arsenic (+3 oxidation state...
Stephanie C. Melkonian, Maria Argos, Megan N. Hall, Yu Chen et al.
BACKGROUND: We utilized data from the Health Effects of Arsenic Longitudinal Study (HEALS) in Araihazar, Bangladesh, to evaluate the association of steamed rice consumption with urinary total arsenic concentration and arsenical skin lesions in the overall study cohort (N=18,470) and in a subset with...
Anne K. Bozack, Megan N. Hall, Xinhua Liu, Vesna Ilievski et al.
Background Arsenic exposure through drinking water persists in many regions. Inorganic As (InAs) is methylated to monomethyl-arsenical species (MMAs) and dimethyl-arsenical species (DMAs), facilitating urinary excretion. Arsenic methylation is dependent on one-carbon metabolism, which is influenced ...
Brandilyn A. Peters, Megan N. Hall, Xinhua Liu, Y. Dana Neugut et al.
Kidney disease is emerging as an arsenic (As)-linked disease outcome, however further evidence of this association is warranted. Our first objective for this paper was to examine the potential renal toxicity of As exposure in Bangladesh. Our second objective relates to examining whether the previous...
Christine Marie George, Mary V. Gamble, Vesna Slavkovich, Diane Levy et al.
BACKGROUND: Arsenic can naturally occur in the groundwater without an anthropogenic source of contamination. In Bangladesh over 50 million people are exposed to naturally occurring arsenic concentrations exceeding the World Health Organization's guideline of 10 μg/L. Selenium and arsenic have been s...
Megan M. Niedzwiecki, Xinhua Liu, Megan N. Hall, Tiffany Thomas et al.
BACKGROUND: Depletion of global 5-hydroxymethylcytosine (5-hmC) is observed in human cancers and is strongly implicated in skin cancer development. Although arsenic (As)-a class I human carcinogen linked to skin lesion and cancer risk-is known to be associated with changes in global %5-methylcytosin...
Caitlin G. Howe, Xinhua Liu, Megan N. Hall, Vesna Slavkovich et al.
BACKGROUND: Exposure to inorganic arsenic is associated with numerous adverse health outcomes, with susceptibility differing by sex. Although evidence from in vitro studies suggests that arsenic alters post-translational histone modifications (PTHMs), evidence in humans is limited. OBJECTIVES: The o...
Brandilyn A. Peters, Megan N. Hall, Xinhua Liu, Vesna Slavkovich et al.
Background Arsenic (As) methylation capacity in epidemiologic studies is typically indicated by the proportions of inorganic As (%InAs), monomethylarsonic acid (%MMA), and dimethylarsinic acid (%DMA) in urine as a fraction of total urinary As. The relationship between renal function and indicators o...
Roheeni Saxena, Mary V. Gamble, Gail A. Wasserman, Xinhua Liu et al.
BACKGROUND: Over 57 million people in Bangladesh have been chronically exposed to arsenic-contaminated drinking water. They also face environmental exposure to elevated levels of cadmium (Cd), manganese (Mn), and lead (Pb), all of which have been previously observed in environmental and biological s...
Ahlam Abuawad, Miranda J. Spratlen, Faruque Parvez, Vesna Slavkovich et al.
BACKGROUND: Water-borne arsenic (As) exposure is a global health problem. Once ingested, inorganic As (iAs) is methylated to mono-methyl (MMA) and dimethyl (DMA) arsenicals via one-carbon metabolism (OCM). People with higher relative percentage of MMA (MMA%) in urine (inefficient As methylation), ha...
Megan M. Niedzwiecki, Xinhua Liu, Huiping Zhu, Megan N. Hall et al.
Background Inorganic arsenic (As) is methylated via one carbon metabolism (OCM) to mono- and dimethylated arsenicals (MMA and DMA), facilitating urinary excretion. Hyperhomocysteinemia (HHcys), a marker of impaired OCM, is a risk factor for As-induced skin lesions, but the influences of single nucle...