Chemical research in toxicology
-
Chem. Res. Toxicol. · Apr 2021
Tobacco-Specific Nitrosamines in the Tobacco and Mainstream Smoke of Commercial Little Cigars.
Cigars are among the broad variety of tobacco products that have not been as extensively studied and characterized as cigarettes. Small cigars wrapped in a tobacco-containing sheet, commonly referred to as little cigars, are a subcategory that are similar to conventional cigarettes with respect to dimensions, filters, and overall appearance. Tobacco-specific nitrosamines (TSNAs) are carcinogens in the tobacco used in both little cigars and cigarettes. ⋯ By the ISO nonintense and CI smoking regimens, mainstream smoke NNK and NNN yields showed a moderate to strong correlation (ISO nonintense, R2 = 0.60-0.68, p < 0.0001; CI, R2 = 0.78-0.81, p < 0.0001) with tobacco filler NNK and NNN quantities. In addition, the mainstream smoke NNK and NNN yields of little cigars were determined to be 3- to 5-fold higher compared to previously tested commercial cigarettes. The mainstream smoke NNK and NNN yields have wide variation among commercial little cigars and suggest that, despite design similarities to cigarettes, machine-smoke yields of carcinogenic TSNAs are higher in little cigars.
-
Chem. Res. Toxicol. · Jan 2021
Protection Level and Reusability of a Modified Full-Face Snorkel Mask as Alternative Personal Protective Equipment for Healthcare Workers during the COVID-19 Pandemic.
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 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.
-
Chem. Res. Toxicol. · Sep 2020
A Mechanical Mechanism for Vitamin E Acetate in E-cigarette/Vaping-Associated Lung Injury.
The outbreak of electronic-cigarette/vaping-associated lung injury (EVALI) has made thousands ill. This lung injury has been attributed to a physical interaction between toxicants from the vaping solution and the pulmonary surfactant. In particular, studies have implicated vitamin E acetate as a potential instigator of EVALI. ⋯ Softer membranes would promote adsorption to the air-liquid interface during inspiration as well as collapse from the interface during expiration. These findings indicate the potential for the failure of the pulmonary surfactant upon expiration, attributed to monolayer collapse. This collapse could contribute to the observed EVALI signs and symptoms, including shortness of breath and pneumonitis.
-
Chem. Res. Toxicol. · Sep 2018
ReviewLipidomics Reveals Changes in Metabolism, Indicative of Anesthetic-Induced Neurotoxicity in Developing Brains.
Numerous studies have demonstrated that treatment with high dose anesthetics for a prolonged duration induces brain injury in infants. However, whether anesthetic treatment leading to neurotoxicity is associated with alterations in lipid metabolism and homeostasis is still unclear. ⋯ Finally, whether lipid changes identified in serum of infant monkeys can serve as indicators for the early detection of anesthetic-induced brain injury is described. We believe extensive studies on alterations in lipids after exposure to anesthetics will allow us to better understand anesthetic-induced neurotoxicity, unravel its underlying biochemical mechanisms, and develop powerful biomarkers for early detection/monitoring of the toxicity.
-
Chem. Res. Toxicol. · Sep 2018
Evaluation of E-Vapor Nicotine and Nicotyrine Concentrations under Various E-Liquid Compositions, Device Settings, and Vaping Topographies.
Nicotine is one of the major components of electronic cigarette (e-cigarette) emissions. Nicotyrine is a product of nicotine dehydrogenation in e-vapor and is a known inhibitor of human cytochrome P450 enzyme, which mediates nicotine metabolism. However, the emission of nicotine and especially nicotyrine from e-cigarettes has not been studied under real-world vaping patterns. ⋯ E-cigarette coil temperatures (200-300 °C) favored the formation of nicotyrine: E-cigarette vaping generated 2- to 63-fold more nicotyrine per unit nicotine emission than conventional cigarette smoking. High nicotyrine emission from e-cigarettes indicates that nicotine metabolism could be potentially interrupted, which could lead to reduced e-cigarette usage, and result in lower exposures to toxic chemicals (e.g., formaldehyde and acetaldehyde). However, higher serum nicotine levels might increase cancer risks by stimulating nicotinic acetylcholine receptors (nAchRs).