High-throughput, simultaneous quantitation of hemoglobin adducts of acrylamide, glycidamide, and ethylene oxide using UHPLC-MS/MS.

Ethylene oxide (EO), acrylamide (AA) and glycidamide (GA) exposures are associated with mammary tumors in animals. Currently available information about human exposure to these chemicals is limited creating the need for analytical methods to assess their exposure. We developed a sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to simultaneously quantitate hemoglobin (Hb) N-terminal valine adducts of AA (HbAA), GA (HbGA), and EO (HbEO) using modified Edman reaction. The limits of detection of this method were 3.9, 4.9 and 12.9 in pmol/g Hb for HbAA, HbGA and HbEO, respectively. The among-day and within-day precision for all analytes determined with three levels of quality control pools ranged from 2.2-13.0% in percent coefficient of variation (%CV). The accuracy determined by standard addition was between 94 and 111% among all analytes. The median HbAA, HbGA and HbEO values in 34 self-reported non-smokers were 64.9, 45.3 and 113.6 pmol/g Hb and in 70 self-reported smokers were 127.8, 69.6 and 237.1 pmol/g Hb, respectively. HbAA, HbGA, and HbEO were detectable in all samples suggesting that the described method is suitable for measuring hemoglobin adducts of AA, GA and EO in the general population. This high throughput method can process 148 samples in 8 h. The HbEO/HbGA ratio appears independent of the HbAA levels in non-smokers and decreases with increasing HbAA concentration in smokers. This new method is suitable for measuring human exposure to AA, GA and EO and can provide further insight into the metabolism of these chemicals in humans.

Ultraperformance Liquid Chromatography Tandem Mass Spectrometry Method To Determine Formaldehyde Hemoglobin Adducts in Humans as Biomarker for Formaldehyde Exposure.

Formaldehyde (FA) is an environmental chemical classified as a human carcinogen. It is highly reactive and can bind covalently with hemoglobin (Hb) to produce Hb adducts. Measurement of these Hb adducts provides valuable information about exposure to this chemical. We developed a robust, ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantifying FA-Hb adducts in red blood cells. The method measures the FA-VHLTPEEK peptide after trypic digestion. The peptide is a FA adduct at the N-terminus of the beta chain of human Hb. Method mean (±SD) accuracy, determined by recovery in quality control and blank material was 103.2% ± 8.11. The mean among-day and within-day coefficients of variation determined at three concentration levels (%CV) were 9.2% (range: 7.2-10.2%) and 4.9% (range 3.1-7.3%), respectively. The limit of detection was 3.4 nmol/g Hb. This method was applied to the analysis of 135 human blood samples, and FA-VHLTPEEK was detected in all study samples. FA-VHLTPEEK concentrations were not significantly different between smokers and nonsmokers. This work is the first validated UPLC-MS/MS method in which a FA peptide derived from a FA-Hb adduct could be used to monitor exposure to FA in population studies.

Alcohol intake and invasive breast cancer risk by molecular subtype and race in the Carolina Breast Cancer Study.

PURPOSE: Alcohol is an established breast cancer risk factor, but there is little evidence on whether the association differs between African Americans and whites. METHODS: Invasive breast cancers (n = 1,795; 1,014 white, 781 African American) and age- and race-matched controls (n = 1,558; 844 white, 714 African American) from the Carolina Breast Cancer Study (Phases I-II) were used to estimate odds ratios (ORs) and 95 % confidence interval (CI) for pre-diagnosis drinks per week and breast cancer risk. RESULTS: African American controls reported lower alcohol intake than white controls across all age groups. Light drinking (0 to ≤2 per week) was more prevalent among African American controls. Moderate-to-heavy drinking was more prevalent in white controls. African Americans who reported drinking >7 drinks per week had an elevated risk compared to light drinkers [adjusted OR, 95% CI 1.62 (1.03-2.54)]. A weaker association was observed among whites [adjusted OR, 95% CI 1.20 (0.87-1.67)]. The association of >7 drinks per week with estrogen receptor-negative [adjusted OR, 95% CI 2.17 (1.25-3.75)] and triple-negative [adjusted OR, 95% CI 2.12 (1.12-4.04)] breast cancers was significant for African American, but not white women. We observed significantly elevated ORs for heavy intake at ages <25 and >50 years of age for African American women only. We found no evidence of statistical interaction between alcohol intake and oral contraceptive use or smoking. CONCLUSIONS: Drinking more than seven alcoholic beverages per week increased invasive breast cancer risk among white and African American women, with significant increases only among African American women. Genetic or environmental factors that differ by race may mediate the alcohol-breast cancer risk association.

Layer-by-layer deposition of rhenium-containing hyperbranched polymers and fabrication of photovoltaic cells.

Multilayer thin films were prepared by the layer-by-layer (LBL) deposition method using a rhenium-containing hyperbranched polymer and poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (PTEBS). The radii of gyration of the hyperbranched polymer in solutions with different salt concentrations were measured by laser light scattering. A significant decrease in molecular size was observed when sodium trifluoromethanesulfonate was used as the electrolyte. The conditions of preparing the multilayer thin films by LBL deposition were studied. The growth of the multilayer films was monitored by absorption spectroscopy and spectroscopic ellipsometry, and the surface morphologies of the resulting films were studied by atomic force microscopy. When the pH of a PTEBS solution was kept at 6 and in the presence of salt, polymer films with maximum thickness were obtained. The multilayer films were also fabricated into photovoltaic cells and their photocurrent responses were measured upon irradiation with simulated air mass (AM) 1.5 solar light. The open-circuit voltage, short-circuit current, fill factor, and power conversion efficiency of the devices were 1.2 V, 27.1 mu A cm(-2), 0.19, and 6.1x10(-3) %, respectively. The high open-circuit voltage was attributed to the difference in the HOMO level of the PTEBS donor and the LUMO level of the hyperbranched polymer acceptor. A plot of incident photon-to-electron conversion efficiency versus wavelength also suggests that the PTEBS/hyperbranched polymer junction is involved in the photosensitization process, in which a maximum was observed at approximately 420 nm. The relatively high capacitance, determined from the measured photocurrent rise and decay profiles, can be attributed to the presence of large counter anions in the polymer film.

Tailoring and modifications of a ZnO nanostructure surface by the layer-by-layer deposition technique.

Different ZnO nanostructures have been modified using the layer-by-layer polyelectrolyte deposition process. The polymer multilayers were deposited on free standing ZnO tetrapods, ZnO tetrapods on a substrate and ZnO nanorod arrays. In addition, attachment of metallic (Au) nanoparticles to the ZnO nanostructure surface using layer-by-layer deposition was demonstrated. The properties of the ZnO nanostructures with modified surfaces were investigated by electron microscopy, absorption and photoluminescence measurements. A linear increase in polymer thickness with the number of polymer multilayers was confirmed by absorption and transmission electron microscopy. The technique can be readily extended to different nanoparticles and different morphologies of ZnO.