Abstract  Cyclotrimethylenetrinitramine (RDX) has been used extensively as an explosive. Prior to this study no data were available on the metabolism of RDX in animals. Metabolism of 14C-RDX was studied in male and female miniature pigs after a one-time gavage with 41 to 44 mg/kg, (0.8 to 0.9 mCi/animal) in an aqueous suspension of 0.1% carboxymethyl cellulose. Metabolic profiles and identification of 14C-RDX-derived radioactivity in plasma, liver and urine were performed utilizing HPLC radio-scanning and LC/MS/MS analysis. Analytical standards were available for all proposed metabolites. Two HPLC columns with differing elution profiles were used for separation, quantification and tentative identification. Identifications were confirmed using LC/MS/MS. Two metabolites were isolated and identified as 4-nitro-2, 4-diazabutanal and a novel metabolite, 4-nitro- 2-4 diaza-butanamide. Analysis also revealed trace levels of 1-nitroso-3,5-dinitro-1,3,5-triazacyclohexane (MNX), 1,3-dintroso-5-nitro-1,3,5-triazacyclohexane (DNX) and 1,3,5-trinitroso- 1,3,5-triazacyclohexane (TNX) in plasma and showed trace levels of MNX and DNX in urine. No metabolites were detected in the liver samples. Thus RDX was metabolized primarily by a method that accomplished both denitration and oxidative cleavage of the ring structure of this compound to form butanal and butanamide metabolites.

Abstract  Dibutyl Adipate, the diester of butyl alcohol and adipic acid, functions as a plasticizer, skin-conditioning agent, and solvent in cosmetic formulations. It is reportedly used at a concentration of 5% in nail polish and 8% in suntan gels, creams, and liquids. Dibutyl Adipate is soluble in organic solvents, but practically insoluble in water. Dibutyl Adipate does not absorb radiation in the ultraviolet (UV) region of the spectrum. Dibutyl Adipate is not toxic in acute oral or dermal animal toxicity tests. In a subchronic dermal toxicity study, 1.0 ml/kg day-1 caused a significant reduction in body weight gain in rabbits, but 0.5 ml/kg/day was without effect. In a study with dogs, no adverse effects were observed when an emulsion containing 6.25% Dibutyl Adipate was applied to the entire body twice a week for 3 months. Dibutyl Adipate was tested or dermal irritation using rabbits and mice and a none to minimal irritation was observed. Dibutyl Adipate at a concentration of 25 % was not a sensitizer in a guinea pig maximization study. Undiluted Dibutyl Adipate was minimally irritating to the eyes of rabbits and 0.1 % was nonirritating. A significant increase in fetal gross abnormalities was observed in rats given intraperitoneal injections of Dibutyl Adipate at 1.75 ml/kg on 3 separate days during gestation, but no effect was seen in animals given 1.05 ml/kg Dibutyl Adipate was as not genotoxic in either bacterial or mammalian test systems. Clinical patch tests confirmed the absence of skin irritation found in animal tests. Clinical phototoxicity tests were negative. Dibutyl Adipate at 0.1 % was not an ocular irritant in two male volunteers. In a clinical test of comedogenicity, Dibutyl Adipate produced no effect. The Cosmetic Ingredient Review (CIR) Expert Panel recognized that use of Dibutyl Adipate in suntan cosmetic products will result in repeated, frequent exposure in a leave-on product. The available data demonstrate no skin sensitization or cumulative skin irritation, no comedogenicity, and no genotoxicity. Combined with the data demonstrating little acute toxicity, no skin or ocular irritation, and no reproductive or developmental toxicity, these data form an adequate basis for reaching a conclusion that Dibutyl Adipate is safe as a cosmetic ingredient in the practices of use and concentrations as reflected in this safety assessment.

Abstract  Methyl tertiary-butyl ether (MTBE), an oxygenating fuel additive, is a common groundwater contaminant and causes male rat renal tumors at high inhalation exposures. MTBE is primarily metabolized to tertiary-butyl alcohol (TBA), which also causes renal tumors in male rats following chronic exposure. The pharmacokinetics of MTBE and TBA in rats has been described previously with a physiologically based pharmacokinetic (PBPK) model for single exposures by oral gavage or inhalation (Borghoff et al., 1996, Fundam. Appl. Toxicol., 30, 264-75). The model has not been used to predict the pharmacokinetics of MTBE and TBA from chronic drinking water, oral gavage, or inhalation exposures, which will be important for extrapolating effects from chronic rodent exposures to humans. The purpose of this work was to compare PBPK model predictions of the pharmacokinetics of MTBE and TBA in rats from drinking water, oral gavage, and inhalation exposure. The scenarios included exposure via drinking water (10-2ml increments) and oral gavage at both 1 and 15000 ppm MTBE vs. 6 h/d inhalation exposure to 400 and 3000 ppm MTBE for 5 days. Water concentrations represented high environmental concentrations (1 ppm) or concentrations resulting in carcinogenic responses in rats following chronic oral exposure (15000 ppm). Inhalation concentrations were the current NOAEL and LOAEL for MTBE. Model predictions of Cmax, Tmax, AUC, and steady state concentrations of MTBE and TBA in blood were compared among the exposure scenarios. The model predicted significant differences in the pharmacokinetics following drinking water exposure versus oral gavage, with inhalation exposure resembling a drinking water exposure scenario. Differences in TBA pharmacokinetics among exposures were mainly due to slow clearance resulting in accumulation over time. The model predictions of the pharmacokinetics of TBA can be used to extrapolate relevant effects among exposure scenarios in rats.

Abstract  The inhibition of histone deacetylases (HDAC) has been recently suggested as a new mechanism of teratogenesis. Embryonic HDAC inhibition has been demonstrated after dosage of pregnant mice with valproic acid and trichostatin A, and has been correlated, at term of gestation, to typical foetal skeletal abnormalities (axial duplications and respecifications). To better define the relationship between HDAC inhibition and axial abnormalities, in the present work we intraperitoneally treated pregnant mice on day 8 post-coitum with molecules known as HDAC inhibitors in adult cells (butyric acid, apicidin, MS275) but unknown for their teratological profile, or with boric acid (a teratogenic agent able to induce axial malformations but with an unknown mechanism of action). Some females were killed a few hours after the treatment; embryos were processed for immunoblotting or immunohistochemistry by using an antibody anti-hyperacetylated histone H4. The remaining females were sacrificed at term of gestation; foetuses were processed for the skeletal double staining for bone and cartilage. All the tested molecules induced embryonic H4 hyperacetylation, as shown by immunoblot. Interestingly, the immunohistochemistry revealed somites as target organs (according to the results obtained after valproic acid and trichostatin A treatment). Axial malformations were observed in foetuses treated with all the tested substances. The data obtained: (1) confirm the relationship between HDAC inhibition and axial abnormalities; (2) confirm that the somites are the main target organs for this class of molecules; (3) suggest that the HDAC inhibition could be the mechanism on the basis of the boric acid-related axial abnormalities.

Abstract  Tertiary butyl alcohol (TBA) is one of the most widely distributed organic contaminants in ground water at gasoline spill sites. The U.S. EPA does not have a Maximum Contaminant Level (MCL) for TBA in drinking water. Nevertheless, many states have set standards for TBA in drinking water and clean up goals for TBA at gasoline spill sites. Because other contaminants, such as benzene and methyl tertiary butyl ether, are often biologically degraded in anaerobic ground water, the state agencies that implement the Under Ground Storage Tank program rely heavily on monitored natural attenuation to clean up these contaminants at gasoline spill sites. This report reviews the prospects for using monitored natural attenuation to manage the risk from TBA in ground water at gasoline spill sites. The report reviews the distribution of TBA in ground water at gasoline spill sites, the process that produces TBA from anaerobic biodegradation of MTBE, and the prospects for natural biodegradation of TBA in ground water. The report presents data from a microcosm study conducted by U.S. EPA on TBA degradation in sediment from six gasoline spill sites distributed around the United States. Finally the report reviews the limited knowledge on use of stable carbon and stable hydrogen isotopes to evaluate natural biodegradation of TBA at field scale.

Abstract  Organophosphorus esters (OP) are known to make a covalent bond with the active site serine in the consensus sequence GXSXG of esterases and proteases. However, the site of attachment to proteins that have no active site serine has only recently been recognized as tyrosine. In last year's report we provided mass spectrometry evidence that soman, sarin, DFP, chlorpyrifos oxon, dichlorvos, and FP-biotin bound to tyrosine in 3 proteins. We now report binding of organophosphorus agents to tyrosinein 12 proteins. This suggests that diagnosis of exposure to OP may become possible by monitoring adducts on tyrosine, for example in albumin. The advantages of using organophosphorus- labeled albumin as a biomarker of exposure are that the albumin adduct is stable, and the OPalbumin adduct does not age. The soman adduct on plasma butyrylcholinesterase was used to determine the limit of detection of soman exposure ex vivo. A concentration of soman that inhibited butyrylcholinesterase in human plasma 2% was detectable in the multiple reaction monitoring mode of the mass spectrometer.

Abstract  A database of indoor air concentrations of volatile organic compounds (VOCs) (n = 528), formaldehyde (n = 76), and ammonia (n = 47) in office environments was analyzed to suggest interpretation guidelines for chemical measurements in office buildings with suspected indoor air problems. Indoor air samples were collected for VOCs from 176 office buildings, 23 offices for formaldehyde, and 14 office buildings for ammonia in 2001-2006. Although the buildings had reported indoor air complaints, a walk-through inspection by indoor air specialists showed no exceptional sources of indoor air pollutants. The measurements of chemical pollutants did not indicate any clear reason for the complaints. The geometric mean concentration of total volatile organic compounds (TVOC) was 88 microg m(-3) in office rooms and 75 microg m(-3) in the open plan offices. The mechanical supply and exhaust ventilation significantly (p < 0.004) decreased the indoor air concentration of TVOC. The highest mean concentration and frequency distributions were determined for the individual VOCs. The most common VOCs found in > or = 84% of the indoor samples include toluene, xylene (p,m), 1-butanol, nonanal, and benzene. According to concentrations, the most abundant VOCs were 2-(2-ethoxyethoxy)ethanol, acetic acid, 1,2-propanediol, and toluene. The geometric mean concentration of formaldehyde and ammonia in the office buildings was 11 microg m(-3) (3-44 microg m(-3) and 14 microg m(-3) (1-49 microg m(-3), respectively. On the basis of statistical analyses, the guideline value indicating a usual concentration of the pollutant in office buildings is 70 microg m(-3) for TVOC, 7 microg m(-3) for most individual VOCs, 10 microg m(-3) for formaldehyde, and 12 microg m(-3) for ammonia. The guidance value suggested for TVOC is 250 microg m(-3), for formaldehyde 15 microg m(-3), and for ammonia 25 microg m(-3). If the guidance value is exceeded, this may indicate the existence of an exceptional source and the need for additional environmental investigations. The levels should not be used for the evaluation of health risks. The guideline values are applicable in a subarctic climate for modern, urban office buildings.

Abstract  This study evaluated exposure to solvents in eight Italian car painting workshops using environmental sampling and personal sampling with charcoal samplers, and urinary determination of unmetabolized solvents. A simple regression analysis was performed to evaluate relationships between the three series of data. The solvents analysed were toluene, ethylbenzene, 1,2-dichloropropane, n-butylacetate, n-amylacetate, xylene isomers, ethylacetate and benzene. Benzene was found in all shops, at levels around or higher than the 8h time-weighted average limit (8h TWA). Other solvents were found at various levels, from 10^-2 to 10^-1 times the 8h TWA. Air concentrations of toluene, n-butylacetate, xylenes, and benzene were positively correlated with their urinary levels, while a negative correlation was found for ethylbenzene. The health implications of these exposure levels are discussed.

Abstract  The aim of this study was to demonstrate, in guinea-pigs in vivo, the utility of huBuChE as a therapy against percutaneous (p.c.) nerve agent poisoning, following which there is a slower absorption of agent than by the inhalation route and consequently a longer window of opportunity for therapeutic intervention. The first task was to determine the p.c. toxicity of VR in Dunkin-Hartley guinea-pigs. The 24h LD50 was 0.45mg/kg (0.36 0.54 95% CI) and the 48-h LD50 was 0.38 mg/kg (0.31-0.45 95% CI). The second task was to investigate the efficacy of huBuChE therapy following p.c. VR. Following VR (0.6mg/kg, p.c.) guinea-pigs were monitored for the onset of observable signs of systemic cholinergic poisoning. At this time, either huBuChE (24.2 mg/kg) or saline was administered by either the intramuscular or intravenous route. The onset of observable signs of cholinergic therapy used as the trigger for therapy dosing was between 5h and 9h following VR challenge. Preliminary results indicate that therapy using huBuChE via the i.v. route was more effective than therapy via the i.m. route.

Abstract  Journal article.

Abstract  The research described in this report is focused on the development of methods for diagnosis of exposure to chemical agents. In Volume I, the development of a Standard Operating Procedure (SOP) for diagnosis of exposure to sulfur mustard is described, based on mass spectrometric analysis of the sulfur mustard-adducted tripeptide (S-(2-hydroxylethylthi oethyl)-Cys-Pro-Phe), derived from albumin. The SOP for the tripeptide adduct was successfully demonstrated to a scientist of USAMRICD. The method could be set up within one day and the scientist of USAMRICD was able to perform the entire assay on his own after 2 days. Furthermore, in Volume I the mass spectrometric analysis of histidine sulfur mustard adducts is extensively described, as well as an immunoslotblot assay for detection of sulfur mustard adducts to keratin. In Volume II (addendum), it is described how several methods for diagnosis of exposure to chemical agents (sulfur mustard, Lewisite, phosgene, nerve agents) have been improved or developed and subsequently transferred to Centers for Disease Control and Prevention. Furthermore, within this context a generic method for detection of covalently modified human butyrylcholinesterase has been developed, in order to circumvent the shortcomings of the current (specific) assays for diagnosis of exposure to OP-anticholinesterases. Finally, various reference compounds have been synthesized and delivered to CDC.

Abstract  The purpose of this research is to genetically engineer, express, and validate 2 novel biopharmaceutical fusion proteins, designated AGT-185 and AGT-186. Both proteins are fusion proteins of human paraoxonase (PON)-1 variants and a genetically engineered monoclonal antibody (MAb) against the human insulin receptor (HIR). The 2 proteins are intended for development as new treatments of the brain in organophosphate chemical nerve gas attacks.

Abstract  This article presents a project undertaken in view of the substitution of the solvent currently used for removing silicone grease during the maintenance of high-voltage circuit breakers, namely a mixture of trichloroethylene, perchloroethylene and saturated hydrocarbons, which has been identified as the cause of mucous membrane irritation in several workers. Furthermore, trichloroethylene and perchloroethylene are known carcinogens. A nine-step systematic approach was adopted, consisting of supplier surveys, small-scale testing and more in-depth evaluations, leading to the selection of octamethyltrisiloxane. However, for reasons of cost, the enterprise finally selected the "Skysol" solvent (a mixture of saturated hydrocarbons and 3-methoxy-3-methyl-1-butanol).

Abstract  Fossil fuel is a non-renewable resource that causes environmental hazards such as global warming and the release of toxic gases. Most importantly, while oil production reached its peak in 2005, the demand for oil worldwide will double in the next two decades due to the high demands of newly expanding economies such as China and India (with a total of 2.5 billion consumers). It is, therefore, essential to look for and develop alternative renewable sources of fuel. Bio-fuels and biomass are renewable resources that are environmentally friendly, will reduce global warming and can help our nation become less energy dependent. Moreover, production of alternative bio-fuels will utilize abundant stocks of cellulosic biomass present in low-value agricultural commodities, leftover straw, solid garbage waste, waste paper, wood chips and processing wastes, further reducing waste disposal and contributing to the more efficient use of such by-products.

Abstract  Interim rept. 10-12 Sep 2011.

Abstract  Prenatal ethanol exposure results in a spectrum of birth defects and neurobehavioral abnormalities referred to as fetal alcohol spectrum disorders (FASD). One potentially important ethanol target is the L1 neural cell adhesion molecule. L1 is a transmembrane glycoprotein composed of six Ig domains and five fibronectin-type III domains, followed by transmembrane and intracellular domains. Short-chain alcohols (e.g., ethanol and butanol derivatives) show remarkable structural specificity for inhibition of L1-mediated cell adhesion. Other alcohols (e.g., 1-octanol) antagonize ethanol inhibition of L1 cell adhesion and ethanol teratogenesis in mouse whole embryo cultures. To test the hypothesis that there are antagonist binding sites on L1, we have employed the photoactivatable analog of octanol, 3-azioctanol. This agent is remarkably potent at antagonizing ethanol inhibition of L1 adhesion. Azioctanol photoincorporated into a soluble model of L1, consisting of only the six Ig domains. After photolabeling, this polypeptide was digested with trypsin and analyzed by mass spectrometry, which identified Tyr-417 (Y417) and Glu-33 (E33) as sites of photoincorporation. Preliminary modeling of L1, based on the known structure of the homologous 1 and #150;4 Ig domains of axonin-1, suggests that E33 and Y417, on Ig1 and Ig4 respectively, may reside in a single pocket formed by the two Ig domains. Furthermore L120 and G121, in which mutations in humans are associated with neurological disorders, are adjacent to this pocket. Thus, this site likely has functional significance. Identification of the antagonist site will aid in understanding the molecular basis for FASD and may accelerate the development of drugs that block the toxic effects of ethanol on the developing nervous system.

Abstract  Journal article.

Abstract  Annual summary 15 Mar 2004-30 Jun 2007.

Abstract  Technical rept. 1 Mar-30 Sep 2005.