Journal: Chemical Research in Toxicology

Abbreviation

Chem. Res. Toxicol.

Publisher

American Chemical Society

Journal Volumes

ISSN

0893-228X
1520-5010

Description

Filters

Reset filters

Search Results

Publications1 - 10 of 65
  • Protection Level and Reusability of a Modified Full-Face Snorkel Mask as Alternative Personal Protective Equipment for Healthcare Workers during the COVID-19 Pandemic
    Item type: Journal Article
    Schmitt, Jean; Jones, Lewis; Aeby, Elise A.; et al. (2021)
    Chemical Research in Toxicology
    The worldwide outbreak of COVID-19 has drastically increased pressure on medical resources and highlighted the need for rapidly available, large-scale, and low-cost personal protective equipment (PPE). In this work, an alternative full-face mask is adapted from a modified snorkel mask to be used as PPE with two medical-grade filters and a 3D-printed adapter. Since the mask covers the eyes, mouth, and nose, it acts as a full-face shield, providing additional protection to healthcare workers. The SARS-CoV-2 has a size between 60 nm and 140 nm, and airborne viral particles can be carried by larger droplets with sizes up to several millimeters. The minimum filtration efficiency of mechanical and electrostatic filters is usually reached between 30 nm and 300 nm. The filtration efficiency of different medical filters is measured for particles below 300 nm to cover the size of the SARS-CoV-2 and small virus-laden droplets, and determine the minimum efficiency. The filtration performance of the adapted full-face mask is characterized using NaCl particles below 500 nm and different fitting scenarios to determine the minimum protection efficiency. The mask is compared to a commercial respirator and characterized according to the EN 149 standard, demonstrating that the protection fulfills the requirements for the FFP2 level (filtering face-piece 2, stopping at least 94% of airborne particles). The device shows a good resistance to several cycles of decontamination (autoclaving and ethanol immersion), is easy to be produced locally at low cost, and helps to address the shortage in FFP2 masks and face shields by providing adequate protection to healthcare workers against particles <500 nm in size. © 2020 American Chemical Society.
  • Dedication of 35-year Chemical Research in Toxicology Anniversary to Founding Editor Larry Marnett
    Item type: Other Journal Item
    Sturla, Shana J.; Shuck, Sarah; Knutson, Charles G.; et al. (2022)
    Chemical Research in Toxicology
  • A Virtual Issue of Chemical Research in Toxicology in Celebration of the International Day of Women and Girls in Science
    Item type: Other Journal Item
    Bryant-Friedrich, Amanda; Kraegeloh, Annette; Sturla, Shana J. (2023)
    Chemical Research in Toxicology
  • Redox properties and activity of iron-citrate complexes: Evidence for redox cycling
    Item type: Journal Article
    Adam, Fatima I.; Bounds, Patricia L.; Kissner, Reinhard; et al. (2015)
    Chemical Research in Toxicology
  • Preparation and properties of lithium and sodium peroxynitrite
    Item type: Journal Article
    Sturzbecher-Höhne, Manuel; Kissner, Reinhard; Nauser, Thomas; et al. (2008)
    Chemical Research in Toxicology
  • Hydrogen Exchange Equilibria in Glutathione Radicals: Rate Constants
    Item type: Journal Article
    Hofstetter, Dustin; Nauser, Thomas; Koppenol, Willem H. (2010)
    Chemical Research in Toxicology
    The reduction of oxidized glutathione GSSG by hydrated electrons and hydrogen atoms to form GSSG•− is quantitative. The radical anion dissociates into GS• and GS−, and the S-centered radical subsequently abstracts a hydrogen intramolecularly. We observe sequential development of UV absorbance signatures that indicate the formation of both α- and β-carbon-centered radicals. From experiments performed at pH 2 and pH 11.8, we determined forward and reverse rate constants for the overall equilibrium between sulfur-centered and carbon-centered radicals: kforward = 3·105 s−1, kreverse = 7·105 s−1, and K = 0.4. Furthermore, on the basis of the differences between the kinetics traces at 240 and 280 nm, we estimate that α- and β-carbon-centered radicals are formed at a surprising ratio of 1:3. The ratios found at pH 2 also apply to pH 7, with the conclusion that the equilibrium ratio of S-centered:β-centered:α-centered radicals is, very approximately, 8:3:1. The formation of carbon-centered radicals could lead to irreversible damage in proteins via the formation of carbon−carbon bonds or backbone fragmentation.
  • Transcriptomic Responses of Cancerous and Noncancerous Human Colon Cells to Sulforaphane and Selenium
    Item type: Journal Article
    Constantinescu, Simona; Hecht, Katrin; Sobotzki, Nadine; et al. (2014)
    Chemical Research in Toxicology
    Diets enriched with bioactive food components trigger molecular changes in cells that may contribute to either health-promoting or adverse effects. Recent technological advances in high-throughput data generation allow for observing systems-wide molecular responses to cellular perturbations with nontoxic and dietary-relevant doses while considering the intrinsic differences between cancerous and noncancerous cells. In this chemical profile, we compared molecular responses of the colon cancer cell line HT29 and a noncancerous colon epithelial cell line (HCEC) to two widely encountered food components, sulforaphane and selenium. We conducted this comparison by generating new transcriptome data by microarray gene-expression profiling, analyzing them statistically on the single gene, network, and functional pathway levels, and integrating them with protein expression data. Sulforaphane and selenium, at doses that did not inhibit the growth of the tested cells, induced or repressed the transcription of a limited number of genes in a manner distinctly dependent on the chemical and the cell type. The genes that most strongly responded in cancer cells were observed after treatment with sulforaphane and were members of the aldo-keto reductase (AKR) superfamily. These genes were in high agreement in terms of fold change with their corresponding proteins (correlation coefficient r2 = 0.98, p = 0.01). Conversely, selenium had little influence on the cancer cells. In contrast, in noncancerous cells, selenium induced numerous genes involved in apoptotic, angiogenic, or tumor proliferation pathways, whereas the influence of sulforaphane was very limited. These findings contribute to defining the significance of cell type in interpreting human cellular transcriptome-level responses to exposures to natural components of the diet.
  • UV photolysis of 3 nitrotyrosine generates highly oxidizing species
    Item type: Journal Article
    Nauser, Thomas; Koppenol, Willem H.; Pelling, Jill; et al. (2004)
    Chemical Research in Toxicology
  • Enzymatic Acrolein Production System and Its Impact on Human Cells
    Item type: Journal Article
    Hurley, Katherine A.; Folz, Jacob; Zgraggen, Jasmin; et al. (2024)
    Chemical Research in Toxicology
    Acrolein is an environmental toxicant and is also generated by microbial metabolism in the intestinal tract. Aqueous acrolein rapidly dissipates from standard human cell culture media with nondetectable levels after 8 h, hindering cell-based studies to understand its biological impacts. Thus, we developed an extracellular acrolein biosynthesis system to continuously produce acrolein compatible with human cell culture conditions. The approach uses spermine as a precursor, amine oxidase found in fetal calf serum, and catalase to remove the hydrogen peroxide byproduct. We confirmed amine oxidase activity of calf serum using a colorimetric assay and further tested the requirement for catalase in the system to mitigate hydrogen peroxide-induced cytotoxicity. We calibrated responses of human colon cells to this enzymatic acrolein production system by comparing transcriptional responses, DNA adduct formation and cytotoxicity responses to either this system or pure acrolein exposures in a human colon cell line. Several genes related to oxidative stress including HMOX1, and the colorectal cancer-related gene SEMA4A were upregulated similarly between the enzymatic acrolein production system or pure acrolein. The acrolein-DNA adduct gamma-OH-Acr-dG increased in a dose-dependent manner with spermine in the enzymatic acrolein production system, producing a maximum of 1065 adducts per 10(8) nucleosides when 400 mu M spermine was used. This biosynthetic production method provides a relevant model for controlled acrolein exposure in cultured human cells and overcomes current limitations due to its physical properties and limited availability.
  • Chemical and Enzymatic Reductive Activation of Acylfulvene to Isomeric Cytotoxic Reactive Intermediates
    Item type: Journal Article
    Pietsch, Kathryn E.; Neels, James F.; Yu, Xiang; et al. (2011)
    Chemical Research in Toxicology
Publications1 - 10 of 65