Lactate Production can Function to Increase Human Epithelial Cell Iron Concentration.

Introduction: Under conditions of limited iron availability, plants and microbes have evolved mechanisms to acquire iron. For example, metal deficiency stimulates reprogramming of carbon metabolism, increasing activity of enzymes involved in the Krebs cycle and the glycolytic pathway. Resultant carboxylates/hydroxycarboxylates then function as ligands to complex iron and facilitate solubilization and uptake, reversing the metal deficiency.

Heme Oxygenase Activity Correlates with Serum Indices of Iron Homeostasis in Healthy Nonsmokers.

Heme oxygenase (HO) catalyzes the breakdown of heme to carbon monoxide, iron, and biliverdin. While the use of genetically altered animal models in investigation has established distinct associations between HO activity and systemic iron availability, studies have not yet confirmed such participation of HO in iron homeostasis of humans. Carbon monoxide produced through HO activity will bind to hemoglobin in circulating erythrocytes, and therefore, blood carboxyhemoglobin (COHb) can be used as an index of HO activity.

Effects of Environmental Pollutants on Cellular Iron Homeostasis and Ultimate Links to Human Disease.

Chronic disease has increased in the past several decades, and environmental pollutants have been implicated. The magnitude and variety of diseases may indicate the malfunctioning of some basic mechanisms underlying human health. Environmental pollutants demonstrate a capability to complex iron through electronegative functional groups containing oxygen, nitrogen, or sulfur.

Uses of NHANES Biomarker Data for Chemical Risk Assessment: Trends, Challenges, and Opportunities.

Background: Each year, the U.S. NHANES measures hundreds of chemical biomarkers in samples from thousands of study participants.

Perchlorate Exposure is Associated with Oxidative Stress and Indicators of Serum Iron Homeostasis Among NHANES 2005-2008 Subjects.

Perchlorate (ClO4 (-)), an oxidizing agent, is a ubiquitous environmental pollutant. Several studies have investigated its thyroid hormone disrupting properties. Its associations with other biological measures are largely unknown.

Association between Perchlorate and Indirect Indicators of Thyroid Dysfunction in NHANES 2001-2002, a Cross-Sectional, Hypothesis-Generating Study.

Background: A previous study based on NHANES 2001-2002 observed that increased levels of urinary perchlorate were associated with increased levels of thyroid stimulating hormone among all women, and with decreased levels of thyroxine among women with low urinary iodine. No associations were observed for men.

Methods: Using the same NHANES 2001-2002 data, associations of urinary perchlorate with indirect biomarkers of thyroid hormone disruption were investigated.

Perturbation of lipids and glucose metabolism associated with previous 2,4-D exposure: a cross-sectional study of NHANES III data, 1988-1994.

Background: Results from previous population studies showed that mortality rates from acute myocardial infarction and type-2 diabetes during the 1980s and 1990s in rural, agricultural counties of Minnesota, Montana, North and South Dakota, were higher in counties with a higher level of spring wheat farming than in counties with lower levels of this crop. Spring wheat, one of the major field crops in these four states, was treated for 85% or more of its acreage with chlorophenoxy herbicides. In the current study NHANES III data were reviewed for associations of 2,4-dichlorophenoxy acetic acid (2,4-D) exposure, one of the most frequently used chlorophenoxy herbicides, with risk factors that are linked to the pathogenesis of acute myocardial infarction and type-2 diabetes, such as dyslipidemia and impaired glucose metabolism.

Mortality from ischemic heart disease and diabetes mellitus (type 2) in four U.S. wheat-producing states: a hypothesis-generating study.

In this ecologic study I examined ischemic heart disease (IHD) and diabetes mortality in rural agricultural counties of Minnesota, Montana, North Dakota, and South Dakota, in association with environmental exposure to chlorophenoxy herbicides, using wheat acreage as a surrogate exposure. I collected data on agricultural land use and 1979-1998 mortality from the U.S.

Human nails as a biomarker of arsenic exposure from well water in Inner Mongolia: comparing atomic fluorescence spectrometry and neutron activation analysis.

Arsenic (As) is found naturally in the geological strata within the Ba Men Region of Inner Mongolia, China. A study was conducted to compare the total As measurements from two analytical techniques: instrumental neutron activation analysis (INAA) and atomic fluorescence spectrometry (AFS), and to verify nails as an exposure biomarker in this population. In 1999, nail and water samples were collected in a pilot study.

Birth malformations and other adverse perinatal outcomes in four U.S. Wheat-producing states.

Chlorophenoxy herbicides are widely used in the United States and Western Europe for broadleaf weed control in grain farming and park maintenance. Most of the spring and durum wheat produced in the United States is grown in Minnesota, Montana, North Dakota, and South Dakota, with more than 85% of the acreage treated with chlorophenoxy herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA). Rates of adverse birth outcomes in rural, agricultural counties of these states during 1995-1997 were studied by comparing counties with a high proportion of wheat acreage and those with a lower proportion.

Household stove improvement and risk of lung cancer in Xuanwei, China.

Background: Lung cancer rates in rural Xuanwei County, Yunnan Province, are among the highest in China. Residents traditionally burned "smoky" coal in unvented indoor firepits that generated very high levels of air pollution. Since the 1970s, most residents have changed from firepits to stoves with chimneys.

Analyses of micronuclei in exfoliated epithelial cells from individuals chronically exposed to arsenic via drinking water in inner Mongolia, China.

The groundwater in Bayingnormen (Ba Men), located in Central West Inner Mongolia, China, is naturally contaminated with arsenic at concentrations ranging from 50 microg/L to 1.8 mg/L. Various adverse health effects in this region, including cancer, have been linked to arsenic exposure via drinking water.

Cancer mortality in four northern wheat-producing states.

Chlorophenoxy herbicides are used both in cereal grain agriculture and in nonagricultural settings such as right-of-ways, lawns, and parks. Minnesota, North Dakota, South Dakota, and Montana grow most of the spring and durum wheat produced in the United States. More than 90% of spring and durum wheat is treated with chlorophenoxy herbicides, in contrast to treatment of approximately 30% of winter wheat.

Excretion of arsenic in urine as a function of exposure to arsenic in drinking water.

Urinary arsenic (As) concentrations were evaluated as a biomarker of exposure in a U.S. population chronically exposed to inorganic As (InAs) in their drinking water.

Cancer mortality in agricultural regions of Minnesota.

Because of its unique geology, Minnesota can be divided into four agricultural regions: south-central region one (corn, soybeans); west-central region two (wheat, corn, soybeans); northwest region three (wheat, sugar beets, potatoes); and northeast region four (forested and urban in character). Cancer mortality (1980-1989) in agricultural regions one, two, and three was compared to region four. Using data compiled by the National Center for Health Statistics, cancer mortality was summarized by 5-year age groups, sex, race, and county.

Iron intake and the risk of colorectal cancer.

Prospectively gathered data from the National Health and Nutrition Examination Survey I and the National Health Evaluation Follow-Up Study were analyzed to evaluate the risk of colorectal cancer due to consumption of iron. Morbidity and mortality data due to colorectal cancer were available on 14,407 persons first interviewed in 1971 and followed through 1986. A total of 194 possible colorectal cancers occurred in this group over the 15-year period.

Pesticide appliers, biocides, and birth defects in rural Minnesota.

Earlier studies by our group suggested the possibility that offspring of pesticide appliers might have increased risks of birth anomalies. To evaluate this hypothesis, 935 births to 34,772 state-licensed, private pesticide appliers in Minnesota occurring between 1989 and 1992 were linked to the Minnesota state birth registry containing 210,723 live births in this timeframe. The birth defect rate for all birth anomalies was significantly increased in children born to private appliers.

Host determinants of cellular and biochemical constituents of bronchoalveolar lavage fluids. Implications for design of epidemiologic studies.

The effects of demographic characteristics, exercise, environmental exposures, and other host factors on cellular and biochemical constituents of human bronchoalveolar lavage (BAL) fluids were investigated by studying more than 300 specimens obtained from normal volunteers and assayed in a single center. The BAL data demonstrated associations with race, smoking, exercise, skin-test reactions, and blood constituents, and weak or no associations with age, sex, pulmonary function tests (PFT), or ambient ozone exposure. The effect of exercise was relatively strong and more clearly characterized than in previous studies.

Aspirin use and lung, colon, and breast cancer incidence in a prospective study.

A large body of experimental data and several recent epidemiologic studies indicate that aspirin use may decrease cancer risk. The experimental studies found effects at many anatomic sites, whereas the epidemiologic studies saw the greatest effect on mortality from digestive cancers. To provide further human data, we examined the association between aspirin use and cancer risk using data from the National Health and Nutrition Examination Survey I (NHANES I) and the NHANES I Epidemiologic Follow-up Studies (NHEFS).

Effect of residual splenic function and folate levels on the frequency of micronucleated red blood cells in splenectomized humans.

Frequencies of micronucleated erythrocytes in the peripheral blood of splenectomized individuals can be used as an index of genetic damage to erythrocyte precursor cells in the bone marrow. This is in contrast to non-splenectomized humans, whose micronucleated erythrocytes are removed by the spleen. Many subjects whose spleen has been removed surgically have residual spleen tissue and consequent residual spleen function (RSF), which can be measured by the percentage of 'pitted' peripheral red blood cells.

Exposure of humans to ambient levels of ozone for 6.6 hours causes cellular and biochemical changes in the lung.

An acute (2 h) exposure of humans to 0.4 ppm ozone initiates biochemical changes in the lung that result in the production of components mediating inflammation and acute lung damage as well as components having the potential to lead to long-term effects such as fibrosis. However, many people are exposed to lower levels of ozone than this, but for periods of several hours.

Effects of 5-bromo-2-deoxyuridine concentration and alpha-naphthoflavone on the association between smoking and the frequency of sister-chromatid exchanges in lymphocytes from maternal and cord blood.

The frequency of sister-chromatid exchanges was analyzed in maternal and cord blood lymphocytes obtained at delivery from 23 nonsmokers and 21 smokers. Lymphocytes were cultured under 3 conditions: in the presence of 100 microM 5-bromo-2-deoxyuridine (BUdR), 20 microM BUdR and 20 microM BUdR with 40 microM alpha-naphthoflavone (ANF). Under all assay conditions, frequencies of SCEs were consistently higher for maternal lymphocytes than for cord lymphocytes.

Inherited structural cytogenetic abnormalities detected incidentally in fetuses diagnosed prenatally: frequency, parental-age associations, sex-ratio trends, and comparisons with rates of mutants.

Rates of structural chromosome abnormalities were analyzed in 24,951 fetuses studied prenatally in which there were no grounds to suspect an inherited abnormality. In about one in 200 prenatal cytogenetic diagnoses, an unexpected structural abnormality was found. The observed rate was 5.

Chromosomal abnormality rates at amniocentesis and in live-born infants.

Regression-smoothed maternal age-specific rates of six different categories of cytogenetic abnormalities in recent large-scale prenatal cytogenetic studies were multiplied by independently derived fetal selection coefficients--factors that adjust for the excess likelihood of spontaneous loss of cytogenetically abnormal fetuses--to obtain estimated maternal age-specific rates of these categories of cytogenetic abnormalities in live-born infants. The derived rates apply to women whose only risk factor is advanced maternal age. The categories analyzed were 47,+21 (Down's syndrome), 47,+18 (Edwards' syndrome), 47,+13 (Patau's syndrome), 47,XXY (Klinefelter's syndrome), 47,XXX, and the group of other clinically significant abnormalities considered collectively.