Relative oral bioavailability of glycidol from glycidyl fatty acid esters in rats.

In order to quantify the relative bioavailability of glycidol from glycidyl fatty acid esters in vivo, glycidyl palmitoyl ester and glycidol were orally applied to rats in equimolar doses. The time courses of the amounts of glycidol binding to hemoglobin as well as the excretion of 2,3-dihydroxypropyl mercapturic acids were determined. The results indicate that glycidol is released from the glycidyl ester by hydrolysis and rapidly distributed in the organism.

Unexpected brain lesions in lactating Sprague-Dawley rats in a Two-generation Inhalation Reproductive Toxicity Study with pentafluoropropane (HFC-245fa).

The study presented was conducted following the reproductive study guideline OECD Guideline 416 Two-Generation Reproduction Toxicity Study. Sprague-Dawley rats were exposed to 2000, 10,000 and 50,000 ppm of HFC-245fa. There was an unexpected mortality of lactating dams in the medium and high dose group beginning at day 10 of lactation.

Relative oral bioavailability of 3-MCPD from 3-MCPD fatty acid esters in rats.

In order to quantify the relative oral bioavailability of 3-chloropropane-1,2-diol (3-MCPD) from 3-MCPD fatty acid diesters in vivo, 1,2-dipalmitoyl-3-chloropropane-1,2-diol (3-MCPD diester) and 3-MCPD were orally applied to rats in equimolar doses. In both cases, the time courses of 3-MCPD concentrations were measured in blood, various organs, tissues and intestinal luminal contents. The results show that 3-MCPD is released by enzymatic hydrolysis from the 3-MCPD diester in the gastrointestinal tract and distributed to blood, organs and tissues.

A new analytical approach for the comprehensive characterization of polar xenobiotic organic compounds downgradient of old municipal solid waste (MSW) landfills.

Groundwater samples collected downgradient from a former municipal solid waste landfill near Berlin, Germany, were analyzed by GC-MS, HPLC-MS, and HPLC-NMR hyphenated techniques to comprehensively characterize the xenobiotic organic compounds (XOCs). The focus thereby was on the detection and identification of the polar XOCs which were analyzed in the extract obtained after separation of the unpolar components by pre-extraction. HPLC-NMR and HPLC-MS runs were used to identify polar XOCs on-line or to obtain preliminary structure information on the other XOCs.

Unusual polar metabolites in the groundwater of a contaminated waste site indicate a new pathway of mononitrotoluene transformation.

At a mononitrotoluene-contaminated waste disposal site, the groundwater was screened for polar transformation products of mononitrotoluenes, by means of HPLC-MS, HPLC-NMR and further off-line NMR and MS techniques. Besides expected metabolites such as aminotoluenes (ATs) and nitrobenzoic acids (NBAs), three unknowns (di- and tetrahydro-derivatives of (2-oxo-quinolin-3-yl) acetic acid) could be identified which, in the context of explosives and related compounds, are new metabolites. Evidence could be provided by microcosm experiments with 2-nitrotoluene (2-NT) that these metabolites are microbial transformation products of 2-NT under anaerobic conditions.

Development and validation of an analytical method for determination of 3-chloropropane-1,2-diol in rat blood and urine by gas chromatography-mass spectrometry in negative chemical ionization mode.

We have developed a highly selective and sensitive method using gas chromatography-mass spectrometry with negative chemical ionization for measuring 3-chloropropane-1,2-diol (3-MCPD) in rat blood and urine. Samples were adsorbed on silica gel, extracted with ethyl acetate, and derivatized by chemical derivatization with heptafluorobutyric acid anhydride. For quantification, matrix-based calibration curves and 3-MCPD-d (5), as an isotope-labeled internal standard, were used.

Assessment of pulmonary function and serum substance levels in newborn and juvenile rats.

In the context of pharmaceutical development today, studies for pediatric drug approval are requested more and more often by the regulatory authorities. The developing lung represents a potential target in juvenile toxicity studies. Due to physiological differences in prenatal and postnatal development between humans and standard animal models, experimental methods have to be modified to assess pulmonary function, and basic data on respiratory parameters need to be provided.

Use of biocidal products (insect sprays and electro-vaporizer) in indoor areas--exposure scenarios and exposure modeling.

Five commercially available insect sprays were applied in a model room. Spraying was performed in accordance with the manufacturers' instructions and in an overdosed manner in order to simulate worst-case conditions or an unforeseeable misuse. In addition, we examined electro-vaporizers.

Identification of highly polar nitroaromatic compounds in leachate and ground water samples from a TNT-contaminated waste site by LC-MS, LC-NMR, and off-line NMR and MS investigations.

Leachate and ground water samples from a trinitrotoluene-contaminated waste disposal site near a former ammunitions plant in Stadtallendorf, Germany, were analyzed by liquid chromatography (LC)-mass spectrometry (MS) and LC-NMR hyphenated techniques to comprehensively characterize the range of highly polar nitroaromatic compounds. Wherever unknown components could not be identified by comparison with a multistandard, the spectroscopic data obtained on-line were used to make initial structure proposals, which were later confirmed by comparison with authentic reference materials. In those cases where reference materials were not commercially available, unknown compounds were isolated by HPLC cuts and their structures were elucidated by off-line NMR and MS investigations.

Cross validation of multiple methods for measuring pyrethroid and pyrethrum insecticide metabolites in human urine.

The objective of our study was to compare three vastly different analytical methods for measuring urinary metabolites of pyrethroid and pyrethrum insecticides to determine whether they could produce comparable data and to determine if similar analytical characteristics of the methods could be obtained by a secondary laboratory. This study was conducted as a part of a series of validation studies undertaken by the German Research Foundation's Committee on the Standardization of Analytical Methods for Occupational and Environmental Medicine. We compared methods using different sample preparation methods (liquid-liquid extraction and solid-phase extraction with and without chemical derivatization) and different analytical detection methods (gas chromatography-mass spectrometry (single quadrupole), gas chromatography-high resolution mass spectrometry (magnetic sector) in both electron impact ionization and negative chemical ionization modes, and high-performance liquid chromatography-tandem mass spectrometry (triple quadrupole) with electrospray ionization).

Aircraft disinsection: exposure assessment and evaluation of a new pre-embarkation method.

A new "pre-embarkation" method for aircraft disinsection was investigated using two different 2% d-phenothrin containing aerosols. Five experiments in aircrafts of the type Airbus 310 (4x) and Boeing 747-400 (1x) were performed. In the absence of passengers and crew the d-phenothrin aerosol was sprayed under the seat rows and in a second step at the height of approximately 1.

Inhalational and dermal exposures during spray application of biocides.

Data on inhalational and potential dermal exposures during spray application of liquid biocidal products were generated. On the one hand, model experiments with different spraying devices using fluorescent tracers were carried out to investigate the influence of parameters relevant to the exposure (e.g.

Pyrethroids used indoor-ambient monitoring of pyrethroids following a pest control operation.

House dust and airborne particles (PM) were sampled before (T1) and 1 day (T2), 4-6 months (T3) as well as 10-12 months (T4) after a pest control operation (PCO). Cyfluthrin was applied in 11, cypermethrin in 1, deltamethrin in three and permethrin in four interiors. The pyrethroid concentrations in house dust and PM were measured by GC/MS with a detection limit for all pyrethroids of 0.

In-flight spraying in aircrafts: determination of the exposure scenario.

Exposure measurements were carried out in parked aircrafts during and after application of a biocide aerosol spray (simulated in-flight spraying). The aerosol product SRA spray (Standard Reference Aerosol Spray) was used for spraying. Concentrations of the pyrethrins--the active ingredients--in the air of the passenger cabin (airborne particles, measured during spray application and 40 minutes afterwards) varied from 11 to 65 microg/m3; those of the synergist piperonyl butoxide were 200-485 microg/m3.

Human biomonitoring of pyrethrum and pyrethroid insecticides used indoors: determination of the metabolites E-cis/trans-chrysanthemumdicarboxylic acid in human urine by gas chromatography-mass spectrometry with negative chemical ionization.

This work describes a gas chromatographic-mass spectrometric method employing negative chemical ionization (NCI) for the determination of E-cis/trans-chrysanthemumdicarboxylic acid (CDCA) in human urine used as a biomarker for the exposure to pyrethrum and/or certain pyrethroids in insecticide formulations applied indoors. Mixed-mode solid phase extraction was utilized for sample cleanup. Extraction recoveries ranged from 92 to 104% (2-9% R.

Pyrethroids used indoors--biological monitoring of exposure to pyrethroids following an indoor pest control operation.

A prospective epidemiological study with respect to pyrethroid exposure was carried out combining clinical examination, indoor monitoring and biological monitoring. The results of the biological monitoring are presented. Biological monitoring was performed in 57 persons before (T1) as well as 1 day (T2), 3 days (T3), 4-6 months (T4), and 10-12 months (T5) following a pest control operation (PCO) with pyrethroid containing products such as cyfluthrin, cypermethrin, deltamethrin or permethrin.

Development of a gas chromatography-mass spectrometry method for the determination of household insecticides in indoor air.

This work presents a GC-MS method for the determination of 17 household insecticides and acaricides in indoor air. Air samples were collected with a sampling train which consisted of a glass fibre filter and two polyurethane foam plugs, followed by a high-volume air pump. Filters and plugs were analysed separately.

Indoor pyrethroid exposure in homes with woollen textile floor coverings.

In order to investigate human's exposure to permethrin from treated woollen textile floor coverings and possible adverse health effects, a study was carried out in 80 private homes in Hannover (Germany) equipped with woollen textile floor coverings (wool wall-to-wall carpets or woven or knotted rugs). For indoor monitoring, permethrin was determined both in house dust and on suspended particles. While permethrin concentrations in house dust (< 2 mm) were high (arithmetic mean: 53.

Cross-fostering inhalation toxicity study with HCFC-123 in lactating Sprague-Dawley rats.

A study was performed in Sprague-Dawley rats (Crl:CD BR) to differentiate between effects of hydrofluorocarbon 123 (HCFC-123) on the lactating dam or on the fetus using fostering and cross-fostering of the offspring. Pregnant and/or lactating dams without the pups present were exposed to the test substance (1000 ppm) or clean air by whole-body inhalation for 6 h/day from day 6 to 19 post conceptionem (p.c.