Toxicology of 3-monochloropropane-1,2-diol and its esters: a narrative review.

3-Monochloropropane-1,2-diol (3-MCPD) is a chiral molecule naturally existing as a racemic mixture of (R)- and (S)-enantiomers. It was thoroughly investigated during the 1970s as a male antifertility drug until research was abandoned because of the side effects observed in toxicity studies. More than 20 years later, 3-MCPD, both in the free form and esterified to the fatty acids, was detected in vegetable oil and discovered to be a widespread contaminant in different processed foods. This review summarises the main toxicological studies on 3-MCPD and its esters. Current knowledge shows that the kidney and reproductive system are the primary targets of 3-MCPD toxicity, followed by neurological and immune systems. Despite uncertainties, in vivo studies suggest that renal and reproductive toxicity is mediated by toxic metabolites, leading to inhibition of glycolysis and energy depletion. Few acute, short-term, and subchronic toxicity studies have investigated the 3-MCPD esters. The pattern of toxicity was similar to that of free 3-MCPD. Some evidence suggests that the toxicity of 3-MCPD diesters may be milder than 3-MCPD, likely because of an incomplete enzymatic hydrolysis in the equivalent free form in the gastrointestinal tract. Further research to clarify absorption, metabolism, and long-term toxicity of 3-MCPD esters would be pivotal to improve the risk assessment of these compounds via food.

THE SPACE DIMENSION AT THE MICRO LEVEL: MASS SPECTROMETRY IMAGING OF DRUGS IN TISSUES.

Mass spectrometry imaging (MSI) has seen remarkable development in recent years. The possibility of getting quantitative or semiquantitative data, while maintaining the spatial component in the tissues has opened up unique study possibilities. Now with a spatial window of few tens of microns, we can characterize the events occurring in tissue subcompartments in physiological and pathological conditions. For example, in oncology-especially in preclinical models-we can quantitatively measure drug distribution within tumors, correlating it with pharmacological treatments intended to modify it. We can also study the local effects of the drug in the tissue, and their effects in relation to histology. This review focuses on the main results in the field of drug MSI in clinical pharmacology, looking at the literature on the distribution of drugs in human tissues, and also the first preclinical evidence of drug intratissue effects. The main instrumental techniques are discussed, looking at the different instrumentation, sample preparation protocols, and raw data management employed to obtain the sensitivity required for these studies. Finally, we review the applications that describe in situ metabolic events and pathways induced by the drug, in animal models, showing that MSI makes it possible to study effects that go beyond the simple concentration of the drug, maintaining the space dimension. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Development and application of high resolution mass spectrometry analytical method to study and identify the photoinduced transformation products of environmental pollutants.

Terpenes are among the major causes of pleasant or unpleasant odors close to active or inactive landfills. We studied R-limonene and p-cymene environmental degradation products using the heterogeneous photocatalysis mediated by titanium dioxide to explore the odor pollution. The aim of the study was the development of mass spectrometry based methods both hyphenated with GC and HPLC to identify and characterize transformation products (TPs) derived from photodegradation of R-limonene and p-cymene. With the GC-MS method we identified three TPs for R-limonene and two for p-cymene comparing the obtained mass spectra with those in the NIST library. While with HPLC-MS method, thanks to the use of the high resolution of MS tool, we recognized four and five TPs for R-limonene and p-cymene respectively. No p-cymene was detected as R-limonene transformation product. The methods developed were then applied to real environmental samples coming from landfills active (Lan1) or inactive (Lan2 and Lan3) located in northern Italy. R-limonene was detected in the active landfill (Lan1 at the concentration of 2.35 µg/mL) together with one of its TPs and one TP derived from p-cymene. p-Cymene was detected in the other two inactive landfills (Lan2 and Lan3 concentrations 0.025 and 0.15 µg/mL, respectively) together with one of its TP and two TPs coming from R-limonene photodegradation. The finding of TPs together with R-limonene and p-cymene both in active and inactive landfills point out the attention on the reduction of these molecules in the environment to reduce pollution and human risks.

Rapid automated diagnosis of primary hepatic tumour by mass spectrometry and artificial intelligence.

BACKGROUND AND AIMS: Complete surgical resection with negative margin is one of the pillars in treatment of liver tumours. However, current techniques for intra-operative assessment of tumour resection margins are time-consuming and empirical. Mass spectrometry (MS) combined with artificial intelligence (AI) is useful for classifying tissues and provides valuable prognostic information. The aim of this study was to develop a MS-based system for rapid and objective liver cancer identification and classification. METHODS: A large dataset derived from 222 patients with hepatocellular carcinoma (HCC, 117 tumours and 105 non-tumours) and 96 patients with mass-forming cholangiocarcinoma (MFCCC, 50 tumours and 46 non-tumours) were analysed by Probe Electrospray Ionization (PESI) MS. AI by means of support vector machine (SVM) and random forest (RF) algorithms was employed. For each classifier, sensitivity, specificity and accuracy were calculated. RESULTS: The overall diagnostic accuracy exceeded 94% in both the AI algorithms. For identification of HCC vs non-tumour tissue, RF was the best, with 98.2% accuracy, 97.4% sensitivity and 99% specificity. For MFCCC vs non-tumour tissue, both algorithms gave 99.0% accuracy, 98% sensitivity and 100% specificity. CONCLUSIONS: The herein reported MS-based system, combined with AI, permits liver cancer identification with high accuracy. Its bench-top size, minimal sample preparation and short working time are the main advantages. From diagnostics to therapeutics, it has the potential to influence the decision-making process in real-time with the ultimate aim of improving cancer patient cure.

Electronic cigarettes in Italy: a tool for harm reduction or a gateway to smoking tobacco?

INTRODUCTION: More than a decade after electronic cigarettes (e-cigarette) hit the European market, we are still debating whether they may help or hinder tobacco control. It is therefore useful to explore the potential net effect of e-cigarette use in the general population. METHODS: We annually conduct a face-to-face survey on smoking in Italy on a representative sample of the general population aged 15 years or over (52.4 million). A total of 15 406 subjects were interviewed in 2014-2018. We investigated the consequences of using e-cigarettes on tobacco smoking behaviour among ever and regular e-cigarette users. RESULTS: In all, 5.7% of our sample reported ever e-cigarette use. Multivariate analyses showed more use by men, ex-smokers and current smokers. E-cigarette use decreased with age and increased with education and calendar year. Only 1.1% of subjects were regular e-cigarette users. This prevalence rose from 0.4% in 2014-2015 to 1.8% in 2016-2017 and was 1.3% in 2018. Among 522 ever users, 13.2% stopped smoking after trying e-cigarettes and 22.2% started smoking or relapsed after using e-cigarettes. The corresponding estimates among regular users were 24.7% and 28.0%, respectively. CONCLUSIONS: Among Italian e-cigarette users, those (re)starting smoking after using e-cigarettes outnumber those who stop smoking after using e-cigarettes. From a public health point of view, e-cigarettes may have an unfavourable net effect. Consequently, if we are not able to prevent sales of e-cigarettes to non-smokers, this product will more likely stimulate smoking tobacco than reduce harm.

Identification of Sulfonated and Hydroxy-Sulfonated Polychlorinated Biphenyl (PCB) Metabolites in Soil: New Classes of Intermediate Products of PCB Degradation?

In this paper we describe the identification of two classes of contaminants: sulfonated-PCBs and hydroxy-sulfonated-PCBs. This is the first published report of the detection of these chemicals in soil. They were found, along with hydroxy-PCBs, in soil samples coming from a site historically contaminated by the industrial production of PCBs and in background soils. Sulfonated-PCB levels were approximately 0.4-0.8% of the native PCB levels in soils and about twice the levels of hydroxy-sulfonated-PCBs and hydroxy-PCBs. The identification of sulfonated-PCBs was confirmed by the chemical synthesis of reference standards, obtained through the sulfonation of an industrial mixture of PCBs. We then reviewed the literature to investigate for the potential agents responsible for the sulfonation. Furthermore, we predicted their physicochemical properties and indicate that, given the low pKa of sulfonated- and hydroxy-sulfonated-PCBs, they possess negligible volatility, supporting the case for in situ formation from PCBs. This study shows the need of understanding their origin, their role in the degradation path of PCBs, and their fate, as well as their (still unknown) toxicological and ecotoxicological properties.

Drug-Homogeneity Index in Mass-Spectrometry Imaging.

Enhancing drug penetration in solid tumors is an interesting clinical issue of considerable importance. In preclinical research, mass-spectrometry imaging is a promising technique for visualizing drug distribution in tumors under different treatment conditions and its application in this field is rapidly increasing. However, in view of the huge variability among MSI data sets, drug homogeneity is usually manually assessed by an expert, and this approach is biased by interobserver variability and lacks reproducibility. We propose a new texture-based feature, the drug-homogeneity index (DHI), which provides an objective, automated measure of drug homogeneity in MSI data. A simulation study on synthetic data sets showed that previously known texture features do not give an accurate picture of intratumor drug-distribution patterns and are easily influenced by the tumor-tissue morphology. The DHI has been used to study the distribution profile of the anticancer drug paclitaxel in various xenograft models, which were either pretreated or not pretreated with antiangiogenesis compounds. The conclusion is that drug homogeneity is better in the pretreated condition, which is in agreement with previous experimental findings published by our group. This study shows that DHI could be useful in preclinical studies as a new parameter for the evaluation of protocols for better drug penetration.

QSPR analysis of threshold of odor for the large number of heterogenic chemicals.

Quantitative structure-property relationships for odor thresholds based on representation of the molecular structure by the simplified molecular input-line entry system were established using the CORAL software. The total set of compounds with numerical data on the so-called arithmetic odor thresholds ([Formula: see text]) was distributed into the training and validation sets, three times. The average statistical quality of these models is (1) for training set [Formula: see text]; and (2) for validation set [Formula: see text]. Thus, the predictive potential of this approach was confirmed for three different splits into training and validation sets. Domain of applicability and mechanistic interpretation of these models are defined from the probabilistic point of view. The suggested models are built up according to OECD principles.

Personal care products in surface, ground and wastewater of a complex aquifer system, a potential planning tool for contemporary urban settings.

The use and discharge of personal care products (PCPs) result in their presence in the aquatic environment. This study investigates the occurrence and fate of some PCPs in wastewater, surface and groundwater in an urbanized area in the North of Italy. We investigated four UV filters: phenylbenzimidazole sulfonic acid (PBSA), benzophenone-3 (BP3), benzophenone-4 (BP4) and 4 methyl-benzilidine-camphor (4-MBC), and two antibacterial agents: triclosan (TCS) and triclocarban (TCC). BP3, BP4 and PBSA were detected in all WWTPs and concentrations ranged 27-822 ng/L (BP4 > PBSA > BP3). TCS was the only disinfectant detected in wastewater and ranged from <0.2 to 1690 ng/L. Removal efficiencies in WWTPs were good for BP3 and TCS (80-100%), but were quite low for PBSA and BP4 (0-40%). Consequently, PBSA and BP4 were the most abundant substances in surface water, detected up to 560.4 ng/L. TCS was also found in surface water (<0.2-161.0 ng/L). Only PBSA and TCS were found in untreated groundwater, and levels were higher in wells close to rivers, suggesting the contribution of surface water to this contamination, but not from the catchment and the sewer networks. These PCPs were confirmed to be ubiquitous in all the aquifers sampled, being reliable descriptors of human presence. The use of these data as direct indicators of pollutant's loads for the aquifers deriving from human presence could provide early warnings on chemicals that are continuously introduced into surface waters, identifying dynamic urban trends and suggesting paths for the planning in urban regions and for appropriate investment and rehabilitation strategies of infrastructure.

High Penetration of Paclitaxel in Abdominal Wall of Rabbits after Hyperthermic Intraperitoneal Administration of Nab-Paclitaxel Compared to Standard Paclitaxel Formulation.

PURPOSE: Paclitaxel (PTX) is currently used in combination with cisplatin for Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for the treatment of peritoneal carcinomatosis. Albumin-bound PTX is a promising new drug for HIPEC because of its easy solubility in aqueous perfusion medium and possibly because of the tendency of albumin to cross physiological barriers and accumulate in tumor tissue. METHODS: We tested the feasibility of using nab-paclitaxel in rabbits treated by HIPEC for 60 min compared with the classical formulation at an equivalent PTX dose. Samples of perfusate and blood were collected at different time points and peritoneal tissues were collected at the end of perfusion. PTX concentrations were determined by HPLC. The depth of paclitaxel penetration through the peritoneal barrier was assessed by mass spectrometry imaging. RESULTS: PTX after nab-paclitaxel treatment penetrated up to 0.63 mm in the peritoneal wall, but after CRE-paclitaxel, it was not detectable in the peritoneum. Moreover, the peritoneal concentration after nab-paclitaxel was five times that after paclitaxel classical formulation. Despite the high levels reached in the peritoneum, systemic exposure of PTX was low. CONCLUSIONS: Our results show that nab-paclitaxel penetrates into the abdominal wall better than CRE-paclitaxel, in terms of effective penetration and peritoneal tissue concentration.

A simple headspace gas chromatography/mass spectrometry method for the quantitative determination of the release of the antioxidants butylated hydroxyanisole and butylated hydroxytoluene from chewing gum.

RATIONALE: Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are widely used to prevent oxidation and rancidity in foodstuffs, pharmaceutical preparations and cosmetic formulations. Although their safety has been thoroughly investigated, possible endocrine side-effects have been suggested. A useful method for the determination of BHA and BHT in foods is needed to estimate their daily intake through the diet. METHODS: We selected commercial chewing gums as a model of a complex food matrix and developed a new method based on gas chromatography/mass spectrometry. This allows the determination of 130 pg/gum of BHA and 9 pg/gum of BHT. RESULTS: Analysis of different chewing gums from the European market indicated that the two antioxidants were never used together and that the content of BHA was in the range of 220-348 µg/gum and BHT ranged from 278 up to 479 µg/gum. These amounts correspond to 86-157 mg/kg gum for BHA and 170-185 mg/kg gum for BHT, and are both within the maximum levels established by the European Food Safety Authority. Chewing a piece of gum for 15 min resulted in the release of up to 28% of BHA, but no release of BHT was detectable. CONCLUSIONS: A new, simple and rapid method for the determination of BHA and BHT in chewing gums was described. This analytical method, based on headspace sampling, did not require the extraction of antioxidants from chewing gum samples, assuring the absence of any gum material contaminants that might affect the instrumentation. It is also automatable, employing a sequential automatic sampler. This method could be of interest to academic researchers and to food industrialists looking for a new methodological approach for BHA and BHT determination in foodstuffs with complex matrices. Copyright © 2017 John Wiley & Sons, Ltd.

Dynamic measurement of newly formed carbonyl compounds in vapors from electronic cigarettes.

Recently, the formation of carbonyl compound within e-cigarettes usage has been reported. The aim of this study was to develop a new analytical method for the direct analysis of carbonyl compounds in vaporized liquids. Two different types of e-cigarettes and different puff's duration have been evaluated, using a modified smoking machine for vapor generation. An isotopic dilution approach, based on deuterated internal standard addition to the e-liquid before filling the e-cigarette tank, has been developed. Carbonyl compounds have been sampled in vapors using a direct, simple, solid-phase microextraction technique with on-fiber derivatization. Related oximes have been analyzed by gas chromatography/mass spectrometry technique. Results confirmed that new carbonyl compounds are formed during the vaping process, and that formation depends both from the heating device and from puffing topography.

Wastewater-based epidemiological evaluation of the effect of air pollution on short-acting beta-agonist consumption for acute asthma treatment.

Asthma, one of the most common chronic diseases in the world and a leading cause of hospitalization among children, has been associated with outdoor air pollution. We applied the wastewater-based epidemiology (WBE) approach to study the association between the use of salbutamol, a short-acting beta-agonist used to treat acute bronchospasm, and air pollution in the population of Milan, Italy. Composite 24-h samples of untreated wastewater were collected daily and analyzed for human metabolic residues of salbutamol by liquid chromatography tandem mass spectrometry. Corresponding daily outdoor concentrations of particular matter up to 10µm (PM10) and 2.5µm (PM2.5) in aerodynamic diameter, nitrogen dioxide, ozone, sulfur dioxide, and benzene were collected from the public air monitoring network. Associations at different lag times (0-10 days) were assessed by a log-linear Poisson regression model. We found significant direct associations between defined daily doses (DDD) of salbutamol and mean daily concentrations of PM10 and PM2.5 up to nine days of lag time. The highest rate ratio, and 95% confidence interval (CI), of DDD of salbutamol was 1.06 (95% CI: 1.02-1.10) and 1.07 (95% CI: 1.02-1.12) at seven days of lag time and for an increase of 10 µg/m(3) of PM10 and PM2.5, respectively. Reducing the mean daily PM10 concentration in Milan from 50 to 30µg/m(3) means that 852 (95% CI: 483-1504) daily doses of salbutamol per day would not be used. These results confirm the association between asthma and outdoor PM10 and PM2.5 and prove the potential of the WBE approach to quantitatively estimate the relation between environmental exposures and diseases.

Automated online solid-phase extraction-liquid chromatography mass spectrometric analysis of dithianon in water.

An automated online solid-phase extraction-liquid chromatography mass spectrometry (SPE-LC/MS) method was developed for the quantification of dithianon in surface water samples, using warfarin as internal standard. The method was developed on a liquid chromatography (LC) system with Flexible Cube interfaced to a quadrupole time-of-flight (Q-TOF) mass spectrometer. A small volume of acidified water (1 mL) was spiked with internal standard, pre-concentrated online on polymeric cartridges and analyzed by full-scan MS in high-resolution conditions. The quantitative data were obtained by [M]-• of dithianon and [M - H]- of warfarin, used as internal standard. The chromatographic separation was performed on a C18 column with a gradient mobile phase consisting of acetonitrile and water containing 0.05% acetic acid. The method was validated to measure concentrations of dithianon in the range of 0.010-4 µg L-1 in surface water samples. Twenty real water samples, collected from Torrente Novella, Val di Non (TN, Northern Italy), during fungicide treatments of large apple orchards, were analyzed. All samples were kept in glass bottles and stored in the lab at -20°C until analysis. It was found that in all samples dithianon was undetectable: if it is present, its concentration was lower than the limit of detection (LOD) (0.008 µg L-1.To investigate the stability of dithianon, a series of water samples were spiked at different concentrations and analyzed after different storage conditions. Results suggested that dithianon is not stable in water stored at -20°C at neutral or basic pH, but the addition of acetic acid to pH = 3.5 increases its stability to at least two weeks.

Odor threshold prediction by means of the Monte Carlo method.

A large set of organic compounds (n=906) has been used as a basis to build up a model for the odor threshold (mg/m(3)). The statistical characteristics of the best model are the following: n=523, r(2)=0.647, RMSE=1.18 (training set); n=191, r(2)=0.610, RMSE=1.03, (calibration set); and n=192, r(2)=0.686, RMSE=1.06 (validation set). A mechanistic interpretation of the model is presented as the lists of statistical promoters of the increase and decrease in the odor threshold.

A novel approach for monitoring tobacco use in local communities by wastewater analysis.

OBJECTIVE: We propose a novel approach for measuring tobacco use in a community through the chemical analysis of nicotine metabolites in urban wastewater. It offers frequent monitoring and 'real-time', 'evidence-based' estimates of tobacco consumption which may complement epidemiological surveillance systems normally repeated only every few years. METHODS: Two urinary metabolites of nicotine, namely cotinine and trans-3'-hydroxycotinine, were selected as biomarkers of tobacco consumption in urban wastewater. During smoking, a known amount of nicotine is absorbed and after metabolism excreted as metabolites in urine, ending up in the wastewater; quantitative analysis of the metabolites in the wastewater allows back-calculation of the nicotine collectively absorbed by the population producing the sewage and, indirectly, their tobacco use. Representative samples of wastewater were collected from sewage treatment plants in eight Italian cities and analysed by mass spectrometry. Mass loads of the metabolites were used to estimate nicotine consumption. RESULTS: Wastewater analysis in the cities under study was used to estimate the number of cigarettes smoked, in order to compare the results of this study with those obtained from population surveys. The number of cigarettes calculated with the two methods were closely comparable and wastewater analysis was sufficiently sensitive to confirm the differences in tobacco consumption between northern and southern Italy, previously described in population surveys. CONCLUSIONS: The described approach can serve as a supplementary indicator of tobacco consumption in local communities. This approach can provide objective and updated information, which are useful to assess the efficacy of tobacco-control interventions, with the aim of designing and implementing effective tobacco control plans.

Preclinical Activity of Two Paclitaxel Nanoparticle Formulations After Intraperitoneal Administration in Ovarian Cancer Murine Xenografts.

Background: Epithelial ovarian cancer is associated with high mortality due to diagnosis at later stages associated with peritoneal involvement. Several trials have evaluated the effect of intraperitoneal treatment. In this preclinical study, we report the efficacy, pharmacokinetics and pharmacodynamics of intraperitoneal treatment with two approved nanomolecular formulations of paclitaxel (nab-PTX and mic-PTX) in a murine ovarian cancer xenograft model. Methods: IC50 was determined in vitro on three ovarian cancer cell lines (OVCAR-3, SK-OV-3 and SK-OV-3-Luc IP1). EOC xenografts were achieved using a modified subperitoneal implantation technique. Drug treatment was initiated 2 weeks after engraftment, and tumor volume and survival were assessed. Pharmacokinetics and drug distribution effects were assessed using UHPLC-MS/MS and MALDI imaging mass spectrometry, respectively. Pharmacodynamic effects were analyzed using immunohistochemistry and transmission electron microscopy using standard protocols. Results: We demonstrated sub-micromolar IC50 concentrations for both formulations on three EOC cancer cell lines in vitro. Furthermore, IP administration of nab-PTX or mic-PTX lead to more than 2-fold longer survival compared to a control treatment of IP saline administration (30 days in controls, 66 days in nab-PTX treated animals, and 76 days in mic-PTX animals, respectively). We observed higher tissue uptake of drug following nab-PTX administration when compared to mic-PTX, with highest uptake after 4 hours post-treatment, and confirmed this lower uptake of mic-PTX using HPLC on digested tumor samples. Furthermore, apoptosis was not increased in tumor implants up to 24h post-treatment. Conclusion: Intraperitoneal administration of both nab-PTX and mic-PTX results in a significant anticancer efficacy and survival benefit in a mouse OC xenograft model.

Protectiveness of NAM-based hazard assessment - which testing scope is required?

Hazard assessment (HA) requires toxicity tests to allow deriving protective points of departure (PoDs) for risk assessment irrespective of a compound's mode of action (MoA). The scope of in vitro test batteries (ivTB) thereby necessitated for systemic toxicity is still unclear. We explored the protectiveness regarding systemic toxicity of an ivTB with a scope, which was guided by previous findings from rodent studies, where examining six main targets, including liver and kidney, was sufficient to predict the guideline scope-based PoD with high probability. The ivTB comprises human in vitro models representing liver, kidney, lung and the neuronal system covering transcriptome, mitochondrial dysfunction and neuronal outgrowth. Additionally, 32 CALUX®- and 10 HepG2 BAC-GFP reporters cover a broad range of disturbance mechanisms. Eight compounds were chosen for causing adverse effects such as immunotoxicity or anemia in vivo, i.e., effects not directly covered by assays in the ivTB. PoDs derived from the ivTB and from oral repeated dose studies in rodents were extrapolated to maximum unbound plasma concentrations for comparison. The ivTB-based PoDs were one to five orders of magnitude lower than in vivo PoDs for six of eight compounds, implying that they were protective. The extent of in vitro response varied across test compounds. Especially for hematotoxic substances, the ivTB showed either no response or only cytotoxicity. Assays better capturing this type of hazard would be needed to complement the ivTB. This study highlights the potentially broad applicability of ivTBs for deriving protective PoDs of compounds with unknown MoA.

Animal tests are used to determine which amount of a chemical is toxic ('threshold of toxicity') and which organs are affected. In principle, the threshold can also be derived solely from tests with cultured cells. However, only a limited number of cell types can practically be tested, so one challenge is to determine how many and which types shall be tested. In animal studies, only few organs including liver and kidney are regularly among those most sensitively affected. We explored whether a cell-based test battery representing these sensitive organs and covering important mechanisms of toxicity can be used to derive protective human thresholds. To challenge this approach, eight chemicals were tested that primarily cause effects in organs not directly represented in our test battery. Results provided protective thresholds for most of the investigated compounds and gave indications how to further improve the approach towards a full-fledged replacement for animal tests.

Nucleobase adducts bind MR1 and stimulate MR1-restricted T cells.

MR1T cells are a recently found class of T cells that recognize antigens presented by the major histocompatibility complex-I-related molecule MR1 in the absence of microbial infection. The nature of the self-antigens that stimulate MR1T cells remains unclear, hampering our understanding of their physiological role and therapeutic potential. By combining genetic, pharmacological, and biochemical approaches, we found that carbonyl stress and changes in nucleobase metabolism in target cells promote MR1T cell activation. Stimulatory compounds formed by carbonyl adducts of nucleobases were detected within MR1 molecules produced by tumor cells, and their abundance and antigenicity were enhanced by drugs that induce carbonyl accumulation. Our data reveal carbonyl-nucleobase adducts as MR1T cell antigens. Recognizing cells under carbonyl stress allows MR1T cells to monitor cellular metabolic changes with physiological and therapeutic implications.

Evaluation of YouTube videos addressing thoracoscopic sympathectomy using the LAP-VEGaS guidelines.

Introduction: The study aims to evaluate the quality of videos addressing thoracoscopic sympathectomy on YouTube® using the LAParoscopic surgery Video Educational GuidelineS (LAP-VEGaS) criteria. Methods: YouTube was searched using the following keyword: "thoracoscopic sympathectomy" on August 22, 2021. The first 50 videos were analyzed and classified for baseline characteristics and conformity to the LAP-VEGaS checklist. Results: Duration ranged from 19 s to 22 min. The mean number of likes was 14.8 (range 0-80). The mean number of dislikes was 2.5 (range 0-14). The mean number of comments was 8.5 (range 0-67). Nineteen videos did not meet our criteria and were excluded. Regarding the remaining 31 videos, none contained all 16 points of the LAP-VEGaS essential checklist (mean 5.4 points, range 2-14 points), with almost all neglecting preoperative information and outcomes. The mean percentage of conformity was 37% (range 12%-93%). The most viewed videos were not associated with higher conformity to LAP-VEGaS criteria showing only 4/16 points (25%). Conclusions: The quality of videos addressing TS on YouTube®, based on the LAP-VEGaS checklist may be considered not acceptable. Experienced surgeons and surgeons in trainees should be aware of this when using it as a learning resource in their clinical practice.