Overexpression of hMTH1 mRNA: a molecular marker of oxidative stress in lung cancer cells

AbstractHuman MutT homologue (hMTH1) mRNA was overexpressed in SV-40-transformed non-tumorigenic human bronchial epithelial cells (BEAS-2B cells) and in 11 out of 12 human lung cancer cell lines relative to normal human bronchial epithelial cells. Expression levels of hMTH1 mRNA were inversely proportional to cellular levels of 8-oxo-deoxyguanosine. Together, these results suggest that hMTH1 gene expression may represent a molecular marker of oxidative stress that could ultimately be used to elucidate the temporal relationships between oxidative stress, genomic instability and the development of lung cancer

Role of Nitrogen Oxides in Ozone Toxicity

The preparation of ozone/nitrogen oxides mixtures in air containing the nitrate radical, their reaction with the unsaturated lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and the determination of the reaction products in comparison to those obtained from a reaction with only ozone in air by MALDI-FTMS is described. The results indicate the importance of nitrate radical in ozone toxicity

Role of Nitrogen Oxides in Ozone Toxicity

The preparation of ozone/nitrogen oxides mixtures in air containing the nitrate radical, their reaction with the unsaturated lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and the determination of the reaction products in comparison to those obtained from a reaction with only ozone in air by MALDI-FTMS is described. The results indicate the importance of nitrate radical in ozone toxicity

Proton Affinities of Nitrogen Oxyradicals

The proton affinities (PA\u27s) of nitric oxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3) as well as those of the cis- and trans-hydrogenhyponitrite (HONNO) and cis- and trans-dioxodinitrate (ONNO–) radicals were calculated by semi-empirical quantum mechanical calculations (standard Gaussian-2 procedure). The PA calculated values of NO (518.8 kJ mol–1), NO2 (580.5 kJ mol–1) and HNO3 (746.0 kJ mol–1) agree with the experimental values. The PA values for the NO3, ONNO– and HONNO radicals were calculated and adjusted to 580, 1330 and 770 kJ mol–1, respectively

On the Proton Affinity of Peroxynitrite and Peroxynitrous Acid

The proton affinity (PA) of peroxynitrite (ONOO-) and peroxynitrous acid (ONOOH) are calculated to be 1440.5 kJ mol-1 and 749.8 kJ mol-1, respectively. Comparison with results for the nitrous, nitric and peroxynitric acid and their anions supports these estimates

Bovine Follicular Dynamics, Oocyte Recovery,and Development of Oocytes Microinjected with a Green Fluorescent Protein Construct

The present study was carried out to 1) evaluate the viability of in vitro fertilized zygotes after microinjection of DNA, 2) assess the influence of oocyte quality upon the development rate of embryos when injected with DNA, and 3) determine the integration frequency of green fluorescent protein DNA into microinjected embryos. Oocytes were aspirated from ovaries of nine nonlactating Holsteins and were categorized into grades A, B, C, and D. At 16 h after in vitro fertilization, approximately half of the pronuclear stage presumptive zygotes were classified as having 1 pronucleus or 2 pronuclei, and they were microinjected with DNA constructs. A potential predictor of DNA integration frequency at d 10 was assessment of the incidence of green fluorescing embryos. The proportion of cleaved embryos that developed to morulae or blastocysts was not different between groups with 1 pronucleus injected (45%), 1 pronucleus uninjected (64%), or 2 pronuclei injected (49%). However, the development of morulae or blastocysts was higher in the group with 2 pronuclei uninjected (69%). The overall developmental score of green fluorescent protein-positive embryos was higher for grade A oocytes (1.3 &#;&#;0.1) than for grade B (0.8 &#; 0.1), C (0.6 &#;&#;0.1), or D (0.3 &#;&#;0.1) oocytes. The results show that production of transgenic bovine blastocysts can occur from the microinjection of a presumptive zygote having only one visible pronucleus. Initial oocyte quality is an important factor in selection of oocytes suitable for microinjection of DNA and for preimplantation development to produce bovine transgenic embryos

White Dwarfs in Globular Clusters: HST Observations of M4

Using WFPC2 on the Hubble Space Telescope, we have isolated a sample of 258 white dwarfs (WDs) in the Galactic globular cluster M4. Fields at three radial distances from the cluster center were observed and sizeable WD populations were found in all three. The location of these WDs in the color-magnitude diagram, their mean mass of 0.51($\pm 0.03$)M$_{\odot}$, and their luminosity function confirm basic tenets of stellar evolution theory and support the results from current WD cooling theory. The WDs are used to extend the cluster main-sequence mass function upward to stars that have already completed their nuclear evolution. The WD/red dwarf binary frequency in M4 is investigated and found to be at most a few percent of all the main-sequence stars. The most ancient WDs found are about 9 Gyr old, a level which is set solely by the photometric limits of our data. Even though this is less than the age of M4, we discuss how these cooling WDs can eventually be used to check the turnoff ages of globular clusters and hence constrain the age of the Universe.Comment: 46 pages, latex, no figures included, figures available at ftp://ftp.astro.ubc.ca/pub/richer/wdfig.uu size 2.7Mb. To be published in the Astrophysical Journa

Wind speed trends over the contiguous United States

A comprehensive intercomparison of historical wind speed trends over the contiguous United States is presented based on two observational data sets, four reanalysis data sets, and output from two regional climate models (RCMs). This research thus contributes to detection, quantification, and attribution of temporal trends in wind speeds within the historical/contemporary climate and provides an evaluation of the RCMs being used to develop future wind speed scenarios. Under the assumption that changes in wind climates are partly driven by variability and evolution of the global climate system, such changes should be manifest in direct observations, reanalysis products, and RCMs. However, there are substantial differences in temporal trends derived from observational wind speed data, reanalysis products, and RCMs. The two observational data sets both exhibit an overwhelming dominance of trends toward declining values of the 50th and 90th percentile and annual mean wind speeds, which is also the case for simulations conducted using MM5 with NCEP-2 boundary conditions. However, converse trends are seen in output from the North American Regional Reanalysis, other global reanalyses (NCEP-1 and ERA-40), and the Regional Spectral Model. Equally, the relationship between changing annual mean wind speed and interannual variability is not consistent among the different data sets. NCEP-1 and NARR exhibit some tendency toward declining (increasing) annual mean wind speeds being associated with decreased (increased) interannual variability, but this is not the case for the other data sets considered. Possible causes of the differences in temporal trends from the eight data sources analyzed are provided