The purpose of the contract is in support of National Toxicology Program (NTP) hazard identification/hazard assessment activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical agents. The vision of NTP for 21st Century is to focus of inclusion of target-specific, mechanism-based, biological observations. In support of NTP vision, under Intramural Research Program over 100 chemistry tasks were performed during FY08. In an effort to establish new approach to test for the toxicity of a chemical NTP established High Throughput Screening (HTS) program. In support of the High Throughput initiative, different tasks are in progress in three Phases. In the initial Phase, 1028 chemicals which were prepared in DMSO (dimethyl sulfoxid) from a list of 1264 chemicals are undergoing confirmation of identify and purity using GC/MS (gas chromatography/ mass spectrometry) and LC/MS. Presently 440 chemicals have passed the GC/MS 95% purity criteria, 228 are undergoing LC/MS (high pressure liquid chromatography/ mass spectrometry/ analyses, 294 did not pass the GC/MS 95% purity criteria, which might be due to storage breakdown, and the remaining 66 are under evaluation. The second Phase involves aliquoting neat chemical into bar-coded vials for shipment to the DPI/BioFocus repository for later NIH access. Out of the 860 chemicals, over 766 have been aliquoted and will ship as soon as the analyses have confirmed 95% purity or greater. So far 440 have passed the GC/MS 95% purity criteria, 228 are undergoing LC/MS analyses, and the remaining 192 are under evaluation. The third Phase involves preparing fresh 20 mM solutions in DMSO of the 1028 original HTS chemicals and is in progress. Dental composites are complex mixtures of materials that generally consist of an organic resin matrix, reinforcing inorganic filler and a silane-coupling agent. It has been shown that the compound like bisphenol A (BPA) and bis-GMA were present in saliva after placement of a specific dental sealant. It is also been show that these type of chemicals have estrogenic activity. To address this health issue the study was undertaken to know the detectable amount of BPA and its metabolites. The metabolites were isolated from glucuronide conjugates by treating the samples with enzyme. An analytical method, GC/MS/MS (gas chromatography/mass spectrometry/mass spectrometry) was employed for the purpose. The saliva and urine samples were from human volunteers before and after dental treatment. Over 1300 samples received from three different sites (Texas, Maryland and Mississippi) across the country. Based on expanding production, significant potential for occupational exposure and lack of available information to adequately assess safety in humans, 2-methoxy-4-nitroaniline (MONA) was recommended for toxicological studies by the National Cancer Institute (NCI). In support of NTP's toxicological study of MONA in a chronic rodent study, various chemistry projects were undertaken. Preliminary chemical study was conducted to determine the solubility of 2-methoxy-4-nitroaniline in corn oil and 0.5% aqueous methylcellulose. The suspendability and syringeability of the test article were performed in each vehicle at expected dosing concentrations of ~ 100 and ~ 200 mg/mL. The NTP undertook Genetic Toxicity Testing Program to address carcinogenicity based on structure-activity relationships and chemical-induced mechanisms of DNA damage. In support of ongoing Genetic Toxicity Testing Program, chemicals were procured, and shipped to the respective labs for testing. As required special analysis, like extended stability study, were performed. To address the exposure of endocrine disruptor chemicals (EDCs) and their adverse health effects in human and wildlife populations NTP adopted a cell based method, LUMI-CELLTM to test measure the endocrine disruptor activity of chemicals by measuring whether and to what extent the chemical induces or blocks transcription at the estrogen receptor (ER). In support of this program, in the current fiscal years phase 3 program tasks under way to obtain highest purity chemicals available in the market. In view of widespread interest as possible solvent alternatives to volatile organic compounds following four Ionic Liquids (IL) have been nominated for toxicological testing: 1-butyl-1-methyl-pyrrolidinium chloride, 1-butyl-3-methyl-imidazonium chloride, 1-ethyl-3-methyl-imidazonium chloride, and N-butyl-pyridinium chloride. In continues chemistry study on IL's, these compounds were characterized by Fourier transform Infrared spectroscopy (FT-IR) and high performance liquid chromatography (HPLC). Fourteen day palatability studies were conducted to at different concentrations of IL's. Wistar Han rats and B6C3F1 mice were offered drinking water containing for a maximum of 14 consecutive days. Additionally to support research at NIEHS, gastrin releasing peptide (GR peptide) amidated and non-amidated forms have been analyzed using LC/MS/MS. Special analysis were performed to measure the alpha amidating monooxynase activity in prostate cancer cells. Per researcher request special chemicals are synthesized through different custom synthesis laboratories.
