Search

Veratrum poisonings are described in the toxicology literature as multiple Veratrum species grow in different parts of the Northern Hemisphere and are occasionally ingested by mistake. Veratrum toxicity is attributed to the steroidal alkaloids contained in all parts of the plant. In Russia, Veratrum poisonings are more common since there is an over-the-counter Veratrum lobelianum -based tincture, Veratrum Aqua (VA), which is topically used for the treatment of lice infestation. Despite its toxicity, VA is misused in traditional medicine as a remedy for alcohol use disorder. We describe four cases of VA poisoning that occurred in Moscow, Russia. Three main V. lobelianum alkaloids (jervine, protoveratrine A (proA) and protoveratrine B) were determined in patient plasma and urine samples using liquid chromatography–tandem mass spectrometry (LC–MS-MS). Here, we describe a novel validated LC–MS-MS method for jervine and proA quantification. A simple and rapid liquid–liquid extraction with methyl tert -butyl ether was utilized for analyte extraction. Chromatographic separation was achieved using a Poroshell 120 EC-C18 column, and the total run time was 14 min. The lower limit of quantification was 0.1 ng/mL for jervine and proA in both plasma and urine. Biological samples were obtained upon hospital admission and during treatment, thus enabling to get a better understanding of the alkaloid elimination profile. Upon admission, plasma concentrations of jervine (concentration range: 0.10–5.01 ng/mL) prevailed over proA (concentration range: 0–0.67 ng/mL). At this time, proA already reached maximum concentrations in urine (concentration range: 0.15–37.70 ng/mL). Maximum concentrations of jervine in urine were observed 24 h after admission (concentration range: 0.10–9.55 ng/mL). In all cases, plasma concentrations of Veratrum alkaloids correlated with condition severity. Since none of the patients confirmed VA intake, instrumental analysis was the basis for the definitive diagnosis of VA poisoning. [ABSTRACT FROM AUTHOR]

In this work, we have examined the radiation-induced synthetic chemistry occurring in an astrochemically important C2H2–CO system at the molecular level using a matrix isolation approach. The 1:1 C2H2···CO intermolecular complex of linear structure was obtained in the solid low-temperature (5 K) noble gas matrices by deposition of the C2H2/CO/Ng (Ng = Ar, Kr, Xe) gaseous mixtures and characterized by Fourier-transform infrared spectroscopy. It was found that the X-ray radiolysis of the C2H2···CO complex resulted in formation of C3O (tricarbon monoxide), HCCCHO (propynal), c-H2C3O (cyclopropenone), H2CCCO (propadienone), and HC3O (oxoprorynyl radical). This means that the studied complex may be considered as the simplest building block (or minimal size of intermolecular reactor) for cold astrochemistry occurring in mixed interstellar ices. Remarkably, the discovered transformations of the complex actually represent synthetic routes leading to various C3 species, whereas the acetylenic C–H bond cleavage yielding ethynyl radical appears to be a minor process. Prolonged irradiation results in dehydrogenation, while the C3 skeleton is retained. The interpretation of the C2H2···CO radiolysis mechanism (possible reactions pathways) is provided based on the analysis of kinetic curves and matrix effect. Astrochemical implications of the results are discussed. [ABSTRACT FROM AUTHOR]

Investigations of the low-temperature radiation-induced transformations in the C2H2–H2O system are relevant to the chemistry occurring in interstellar and cometary ices. In this work, we applied a matrix isolation technique to study the radiation-driven evolution of this system at molecular level in order to get new mechanistic insight. The 1:1 C2H2⋅ ⋅ ⋅H2O complexes were prepared in various solid noble-gas matrices (Ar, Kr, Xe) and these icy matrices were subjected to X-ray irradiation at 5 K. Decomposition of initial complex and formation of products were monitored by Fourier-transform infrared (FTIR) spectroscopy. It was found that complexation with H2O resulted in significant enhancement of the radiolytic decay of C2H2 molecules and provided new channels for its radiation-induced transformations. Ketene (both isolated H2CCO and in the form of H2CCO–H2 pair), ketenyl radical (HCCO), carbon monoxide (CO), and methane (CH4) were observed as main products of the C2H2⋅ ⋅ ⋅H2O radiolysis. In addition, vinyl alcohol (CH2CHOH) was detected in an Ar matrix. The mechanistic interpretation (reaction routes leading to formation of these products) is discussed on the basis of consideration of kinetic dependences and matrix effects. Conversion of C2H2⋅ ⋅ ⋅H2O to CH4 is a prominent example of water-mediated cleavage of the C≡C triple bond, which may occur under prolonged irradiation in rigid media. Possible astrochemical implications of the obtained results are highlighted. [ABSTRACT FROM AUTHOR]

In addition to the known prominent role of polyunsaturated (phospho)lipids as structural blocks of biomembranes, there is an emerging understanding of another important function of these molecules as a highly diversified signaling language utilized for intra‐ and extracellular communications. Technological developments in high‐resolution mass spectrometry facilitated the development of a new branch of metabolomics, redox lipidomics. Analysis of lipid peroxidation reactions has already identified specific enzymatic mechanisms responsible for the biosynthesis of several unique signals in response to inflammation and regulated cell death programs. Obtaining comprehensive information about millions of signals encoded by oxidized phospholipids, represented by thousands of interactive reactions and pleiotropic (patho)physiological effects, is a daunting task. However, there is still reasonable hope that significant discoveries, of at least some of the important contributors to the overall overwhelmingly complex network of interactions triggered by inflammation, will lead to the discovery of new small molecule regulators and therapeutic modalities. For example, suppression of the production of AA‐derived pro‐inflammatory mediators, HXA3 and LTB4, by an iPLA2γ inhibitor, R‐BEL, mitigated injury associated with the activation of pro‐inflammatory processes in animals exposed to whole‐body irradiation. Further, technological developments promise to make redox lipidomics a powerful approach in the arsenal of diagnostic and therapeutic instruments for personalized medicine of inflammatory diseases and conditions. [ABSTRACT FROM AUTHOR]