Recombinant factor C (rFC) assay and gas chromatography/mass spectrometry (GC/MS) analysis of endotoxin variability in four agricultural dusts.

Endotoxin exposure is a significant concern in agricultural environments due to relatively high exposure levels. The goals of this study were to determine patterns of 3-hydroxy fatty acid (3-OHFA) distribution in dusts from four types of agricultural environments (dairy, cattle feedlot, grain elevator, and corn farm) and to evaluate correlations between the results of gas chromatography/mass spectrometry (GC/MS) analysis (total endotoxin) and biological recombinant factor C (rFC) assay (free bioactive endotoxin). An existing GC/MS-MS method (for house dust) was modified to reduce sample handling and optimized for small amount (<1 mg) of agricultural dusts using GC/EI-MS.

Oral absorption and oxidative metabolism of atrazine in rats evaluated by physiological modeling approaches.

Atrazine (ATRA) is metabolized by cytochrome P450s to the chlorinated metabolites, 2-chloro-4-ethylamino-6-amino-1,3,5-triazine (ETHYL), 2-chloro-4-amino-6-isopropylamino-1, 3, 5-triazine (ISO), and diaminochlorotriazine (DACT). Here, we develop a set of physiologically based pharmacokinetic (PBPK) models that describe the influence of oral absorption and oxidative metabolism on the blood time course curves of individual chlorotriazines (Cl-TRIs) in rat after oral dosing of ATRA. These models first incorporated in vitro metabolic parameters to describe time course plasma concentrations of DACT, ETHYL, and ISO after dosing with each compound.

Development of an immunochemical detection method for atrazine-induced albumin adducts.

Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) is one of the most commonly used herbicides in the United States. Exposures in rodent models have led to a host of biological effects, most notably the suppression of luteinizing hormone surge. Previously, we have reported that diaminochlorotriazine (DACT), an atrazine metabolite, forms a covalent adduct with rat hemoglobin at Cys-125.

Estimating constants for metabolism of atrazine in freshly isolated rat hepatocytes by kinetic modeling.

This study estimated the kinetic constants for oxidative metabolism of atrazine (ATRA) and its chlorotriazine (Cl-TRI) metabolites, 2-chloro-4-ethylamino-6-amino-1,3,5-triazine (ETHYL), 2-chloro-4-amino-6-isopropylamino-1,3,5-triazine (ISO), and diaminochlorotriazine (DACT), using freshly isolated rat hepatocytes. Hepatocytes were incubated with 1.74, 44, 98, and 266 microM ATRA.

Association of serum concentration of organochlorine pesticides with dietary intake and other lifestyle factors among urban Chinese women.

Concerns about the carcinogenic and endocrine-disrupting characteristics of organochlorine pesticides (OCPs) have led to a global ban on OCP use. However, OCPs persist in the environment for decades because of their long half-life. We evaluated serum levels of OCPs and their correlations with usual dietary intake and other lifestyle factors among 250 healthy women who participated as controls in the Shanghai Breast Cancer Study.

Identification of a novel hemoglobin adduct in Sprague Dawley rats exposed to atrazine.

Atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1,3,5-triazine) is one of the most commonly used herbicides in North America and is frequently detected in ground and surface waters. This research investigated possible covalent modifications of hemoglobin following in vivo exposures to atrazine in Sprague Dawley (SD) rats and in vitro incubations with diaminochlorotriazine. SD rats were exposed to 0, 10, 30, 100, and 300 (mg atrazine/kg)/day for 3 days via oral gavages, and blood was drawn at 0 h, 24 h, 72 h, 20 days, 1 month, and 2 months for globin analysis.

Absorption, distribution, and excretion of [14C]-3-chloro-4-methylaniline hydrochloride in two species of birds following a single oral dose.

Ring-labeled [14C]-3-chloro-4-methylaniline hydrochloride (250 microg per bird) was delivered to 21 red-winged blackbirds (Agelaius phoeniceus) and 21 dark-eyed juncos (Junco hyemalis) via oral gavage, and the distribution and excretion of radioactivity were determined at 15 and 30 min and 1, 4, 8, 12, and 24 h (n = 3 per time point). Direct measurement of radioactivity as well as measurement following combustion was accomplished using a liquid scintillation counter. Elimination from most tissues followed a two-compartment model, with very rapid elimination occurring between time 0 and 4 h and a much slower elimination phase occurring after that.

Quantitative identification of atrazine and its chlorinated metabolites in plasma.

The objective of this study was to develop an analytical method to detect and quantitate the chlorotriazine herbicide atrazine (ATRA), and its chlorinated metabolites [desethylatrazine (DE-ATRA), desisopropylatrazine (DI-ATRA), and diaminochlorotriazine (DACT)] in plasma. Control plasma separated from whole rat blood was fortified with known concentrations of ATRA, DE-ATRA, DI-ATRA, and DACT. These compounds were extracted from the plasma using a liquid-liquid extraction technique, and the resulting extracts were derivatized with tetrabutyl ammonium hydroxide and methyl iodide to produce methylated derivatives of ATRA and its chlorinated metabolites.

Pharmacokinetic modeling of disposition and time-course studies with [14C]atrazine.

A physiological pharmacokinetic (PPK) model, with blood, body, and brain compartments, was developed to estimate total plasma chlorotriazine (CI-TRI) time courses (i.e., atrazine [ATRA] and its three chlorinated metabolites) after oral dosing with ATRA.