A dopant-assisted iodide-adduct chemical ionization time-of-flight mass spectrometer based on VUV lamp photoionization for atmospheric low-molecular-weight organic acids analysis.

Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry. In iodine-adduct chemical ionization mass spectrometry (CIMS), the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet (VUV) lamp initiated CIMS for on-line gaseous formic and acetic acids analysis. In this work, we present a new CIMS based on VUV lamp, and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer electrode. Acetone was added to the photoionization zone, and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I-, and the addition of acetone reduced the amount of methyl iodide by 2/3. In the chemical ionization zone, a headspace vial containing ultrapure water was added for humidity calibration, and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation (R2 > 0.95). With humidity calibration, the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88% RH. In this mode, limits of detection of 10 and 50 pptv are obtained for formic and acetic acids, respectively. And the relative standard deviation (RSD) of quantitation stability for 6 days were less than 10.5%. This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus (Qingdao, China). In addition, we developed a simple model based formic acid concentration to assess vehicular emissions.

Investigation of Protein Lysine Acetylation in Antiviral Innate Immunity.

Protein lysine acetylation involved in the antiviral innate immunity contributes to the regulation of antiviral inflammation responses, including type 1 interferon production and interferon-stimulated gene expression. Thus, investigation of acetylated antiviral proteins is vital for the complete understanding of inflammatory responses to viral infections. Immunoprecipitation (IP) assay with anti-targeted-protein antibody or with acetyl-lysine affinity beads followed by immunoblot provides a classical way to determine the potential modified protein in the antiviral innate pathways, whereas mass spectrometry can be utilized to identify the accurate acetylation lysine residues or explore the acetyl-proteomics. We demonstrate here comprehensive methods of protein lysine acetylation determination in virus-infected macrophages and embryonic fibroblast cells or proteins-overexpressed HEK 293 T cells in the context of antiviral innate immunity.

Development and Validation of a Proximity Labeling Fusion Protein Construct to Identify the Protein-Protein Interactions of Transcription Factors.

Dynamic interactions between transcription factors govern changes in gene expression that mediate changes in cell state accompanying injury response and regeneration. Transcription factors frequently function as obligate dimers whose activity is often modulated by post-translational modifications. These critical and often transient interactions are not easily detected by traditional methods to investigate protein-protein interactions. This chapter discusses the design and validation of a fusion protein involving a transcription factor tethered to a proximity labeling ligase, APEX2. In this technique, proteins are biotinylated within a small radius of the transcription factor of interest, regardless of time of interaction. Here we discuss the validations required to ensure proper functioning of the transcription factor proximity labeling tool and the sample preparation of biotinylated proteins for mass spectrometry analysis of putative protein interactors.

Direct analysis in real time mass spectrometry (DART-MS/MS) for rapid urine opioid detection in a clinical setting.

BACKGROUND AND AIMS: Current laboratory methods for opioid detection involve an initial screening with immunoassays which offers efficient but non-specific results and a subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS) confirmation which offers accurate results but requires extensive sample preparation and turnaround time. Direct Analysis in Real Time (DART) tandem mass spectrometry is evaluated as an alternative approach for accurate opioid detection with efficient sample preparation and turnaround time. MATERIALS AND METHODS: DART-MS/MS was optimized by testing the method with varying temperatures, operation modes, extraction methods, hydrolysis times, and vortex times. The method was evaluated for 12 opioids by testing the analytical measurement range, percent carryover, precision studies, stability, and method-to-method comparison with LC-MS/MS. RESULTS: DART-MS/MS shows high sensitivity and specificity for the detection of 6-acetylmorphine, codeine, hydromorphone, oxymorphone, hydrocodone, naloxone, buprenorphine, norfentanyl, and fentanyl in urine samples. However, its performance was suboptimal for norbuprenorphine, morphine and oxycodone. CONCLUSION: In this proof-of-concept study, DART-MS/MS is evaluated for its rapid quantitative definitive testing of opioids drugs in urine. Further research is needed to expand its application to other areas of drug testing.

Integrating MALDI-TOF Mass Spectrometry with Machine Learning Techniques for Rapid Antimicrobial Resistance Screening of Foodborne Bacterial Pathogens.

Although MALDI-TOF mass spectrometry (MS) is considered as the gold standard for rapid and cost-effective identification of microorganisms in routine laboratory practices, its capability for antimicrobial resistance (AMR) detection has received limited focus. Nevertheless, recent studies explored the predictive performance of MALDI-TOF MS for detecting AMR in clinical pathogens when machine learning techniques are applied. This chapter describes a routine MALDI-TOF MS workflow for the rapid screening of AMR in foodborne pathogens, with Campylobacter spp. as a study model.

Identifying Putative Biomarkers of Foodborne Pathogens Using a Metabolomic Approach.

Metabolomics is the study of low molecular weight biochemical molecules (typically <1500 Da) in a defined biological organism or system. In case of food systems, the term "food metabolomics" is often used. Food metabolomics has been widely explored and applied in various fields including food analysis, food intake, food traceability, and food safety. Food safety applications focusing on the identification of pathogen-specific biomarkers have been promising. This chapter describes a nontargeted metabolite profiling workflow using gas chromatography coupled with mass spectrometry (GC-MS) for characterizing three globally important foodborne pathogens, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica, from selective enrichment liquid culture media. The workflow involves a detailed description of food spiking experiments followed by procedures for the extraction of polar metabolites from media, the analysis of the extracts using GC-MS, and finally chemometric data analysis using univariate and multivariate statistical tools to identify potential pathogen-specific biomarkers.

Atriplex hortensis var. 'rubra' extracts and purified amaranthin-type pigments reduce oxidative stress and inflammatory response in LPS-stimulated RAW264.7 cells.

The use of direct injection ion mobility mass spectrometry (DI-IM-MS) to detect and identify betacyanin pigments in A. hortensis 'rubra' extracts was explored for the first time, with results compared to conventional LC-MS/MS analysis. The anti-inflammatory activities of leaf and seed extracts, alongside purified amaranthin and celosianin pigments, were investigated using a model of lipopolysaccharide (LPS)-activated murine macrophages. Extracts and purified pigments significantly inhibited the production of prostaglandin E2 and NO by up to 90% and 70%, respectively, and reduced the expression of Il6, Il1b, Nos2, and Cox2. Leaf and seed extracts also decreased secretion of Il6 and Il1b cytokines and reduced protein levels of Nos2 and Cox2. Furthermore, extracts and purified pigments demonstrated potent dose-dependent radical scavenging activity in a cellular antioxidant activity assay (CAA) without any cytotoxic effects. Our research highlights the promising biological potential of edible, climate-resilient A. hortensis 'rubra' as a valuable source of bioactive compounds.

Rapid and accurate detection of cinnamon oil adulteration in perilla leaf oil using atmospheric solids analysis probe-mass spectrometry.

Perilla leaf oil (PLO) is a global premium vegetable oil with abundant nutrients and substantial economic value, rendering it susceptible to potential adulteration by unscrupulous entrepreneurs. The addition of cinnamon oil (CO) is one of the main adulteration avenues for illegal PLOs. In this study, new and real-time ambient mass spectrometric methods were developed to detect CO adulteration in PLO. First, atmospheric solids analysis probe tandem mass spectrometry combined with principal component analysis and principal component analysis-linear discriminant analysis was employed to differentiate between authentic and adulterated PLO. Then, a spectral library was established for the instantaneous matching of cinnamaldehyde in the samples. Finally, the results were verified using the SRM mode of ASAP-MS/MS. Within 3 min, the three methods successfully identified CO adulteration in PLO at concentrations as low as 5% v/v with 100% accuracy. The proposed strategy was successfully applied to the fraud detection of CO in PLO.

Examination of primary aromatic amines content in polylactic acid straws and migration into food simulants using SERS with LC-MS.

Polylactic acid (PLA) straws hold eco-friendly potential; however, residual diisocyanates used to enhance the mechanical strength can generate carcinogenic primary aromatic amines (PAAs), posing health risks. Herein, we present a rapid, comprehensive strategy to detecting PAAs in 18 brands of food-grade PLA straws and assessing their migration into diverse food simulants. Surface-enhanced Raman spectroscopy was conducted to rapidly screen straws for PAAs. Subsequently, qualitative determination of migrating PAAs into various food simulants (4 % acetic acid, 10 % ethanol, 50 % ethanol) occurred at 70 °C for 2 h using liquid chromatography-mass spectrometry. Three PAAs including 4,4'-methylenedianiline, 2,4'-methylenedianiline, and 2,4-diaminotoluene were detected in all straws. Specifically, 2,4-diaminotoluene in 50 % ethanol exceeded specific migration limit of 2 µg/kg, raising safety concerns. Notably, PAAs migration to 10 % and 50 % ethanol surpassed that to 4 % acetic acid within a short 2-hour period. Moreover, PLA straws underwent varying degrees of shape changes before and after migration. Straws with poly(butylene succinate) resisted deformation compared to those without, indicating enhanced heat resistance, while poly(butyleneadipate-co-terephthalate) improved hydrolysis resistance. Importantly, swelling study unveiled swelling effect wasn't the primary factor contributing to the increased PAAs migration in ethanol food simulant, as there was no significant disparity in swelling degrees across different food simulants. FT-IR and DSC analysis revealed higher PAAs content in 50 % ethanol were due to highly concentrated polar ethanol disrupting hydrogen bonds and van der Waal forces holding PLA molecules together. Overall, minimizing contact between PLA straws and alcoholic foods is crucial to avoid potential safety risks posed by PAAs.

Proteomic analysis of peripheral blood mononuclear cells in first episode psychosis - Protein and peptide-centered approaches to elucidate potential diagnostic biomarkers.

Diagnosing patients suffering from psychotic disorders is far from being achieved with molecular support, despite all the efforts to study these disorders from different perspectives. Characterizing the proteome of easily obtainable blood specimens, such as the peripheral blood mononuclear cells (PBMCs), has particular interest in biomarker discovery and generating pathophysiological knowledge. This approach has been explored in psychiatry, and while generating valuable information, it has not translated into meaningful biomarker discovery. In this project, we report the proof-of-concept of a methodology that aims to explore further information obtained with classical proteomics approaches that is easily overlooked. PBMC samples from first-episode psychosis and control subjects were subjected to a SWATH-MS approach, and the classical protein relative quantification was performed, where 389 proteins were found to be important to distinguish the two groups. Individual analysis of the quantified peptides was also performed, highlighting peptides of unchanged proteins that were significantly altered. With the combination of protein- and peptide-centered proteomics approaches, it is possible to highlight that information about proteoforms, namely regulation at the peptide level possibly due to post-translational modifications, is routinely overlooked and that its diagnostic potential should be further explored. SIGNIFICANCE: Our exploratory findings highlight the potential of MS-based proteomics strategies, combining protein- and peptide-centered approaches, to aid clinical decision-making in first-episode psychosis, helping to establish early biomarkers for schizophrenia and other psychotic disorders. Particularly, the less popular peptide-centered approach allows the identification/measurement of overlooked modulated peptides that may have potential biomarker characteristics. The application in parallel of protein- and peptide-centered strategies is transversal to research of other diseases, potentially allowing a more comprehensive characterization of the metabolic/pathophysiological alterations related to a specific disease.

Trace rare earth elements analysis in atmospheric particulates and cigar smoke by ICP-MS after pretreatment with magnetic polymers.

BACKGROUND: Some heavy metals could be ingested into human body through breathing besides diet and drinking. Atmospheric particulates and smoke are main sources of this kind for the metals' exposure to human. Compared with environmental water, the methodologies for trace metals in particulates and smoke samples with more complex matrix are much less. Magnetic functional sorbents can be designed to remove complex matrix and enrich target analytes. The combination of magnetic solid phase extraction (MSPE) with highly sensitive inductively coupled plasma mass spectrometry (ICP-MS) detection is a good alternative for the analytical purpose. (92). RESULTS: Magnetic polymers were synthesized through free radical polymerization with Fe3O4 nanoparticles as the core and 2-methyl-2-hydroxyethyl 2-acrylate-2-hydroxyethyl ester phosphate as external modifier. The sorbent showed a high phosphorus content (2.7 wt%) and good selectivity to target REEs, along with good reusability (at least 45 times) and chemical stability. With the consumption of 150 mL aqueous solution, an enrichment factor of 300 was obtained by the proposed method, leading to low detection limits (0.001-0.2 ng L-1) for 15 REEs. The application potential of the method was further evaluated by analyzing local atmospheric particulate and cigar smoke samples. Recovery of 86.3-107 % in digested total suspended particulate (TSP) was obtained for 15 REEs, demonstrating a good anti-interference ability of the method. Target REEs in TSP, PM2.5 and PM10 samples were found to be 0.01-2.81, 0.006-1.09 and 0.009-2.46 ng m-3, respectively, and none of them were detected in the collected cigar smoke. (148) SIGNIFICANCE: The method of MSPE-ICP-MS was demonstrated with good potential for trace analysis in complex sample matrix, probably due to the good selectivity of the functionalized polymers. With the design and fabrication of specific functionalized magnetic sorbents, other heavy metals can be monitored in those samples which would be intake by human breathing. It provided an efficient strategy for the evaluation of metals' health risk in particulates and smoke samples. (69).

Enabling high-sensitivity live single-cell mass spectrometry using an integrated electrical lysis and nano electrospray ionization interface.

BACKGROUND: Live single-cell metabolomic studies encounter inherent difficulties attributed to the limited sample volume, minimal compound quantity, and insufficient sensitivity in the Mass Spectrometry (MS) method used to obtain single-cell data. However, understanding cellular heterogeneity, functional diversity, and metabolic processes within individual cells is essential. Exploring how individual cells respond to stimuli, including drugs, environmental changes, or signaling molecules, offers insights into biology, oncology, and drug discovery. Efficient release of cell contents (lysis) is vital for accurate metabolite detection at the single-cell level. Despite this, traditional approaches in live single cell metabolomics methods do not emphasize efficient lysis to prevent sample dilution. Instead, current live single cell metabolomics methods use direct infusion to introduce the cell into the mass spectrometry without prior chromatographic separation or a lysis step, which adversely affects sensitivity and metabolic coverage. RESULTS: To address this, we developed an integrated single-cell electrical lysis and nano spray (SCEL-nS) platform coupled to an Orbitrap MS capable of efficiently lysing a single cell after being sampled with specially manufactured micropipettes. Lysis efficiency was validated by comparing live cell stain fluorescent intensities of intact and electrically lysed cells through microscopy imaging. The SCEL-nS platform successfully induced the breakdown of a single cell, significantly reducing the live cell stain's fluorescent intensity indicating cell membrane breakdown. Additionally, SCEL-nS was validated by measuring single cells spiked with the anti-cancer drug tamoxifen by MS. SCEL-nS use resulted in statistically significant increase in the peak measured by the method compared to the traditional non-lysis method. SIGNIFICANCE: Overall, our results demonstrate that the newly incorporated SCEL-nS platform achieved higher sensitivities compared to traditional live single cell analysis methods.

Development of a comprehensive normal-phase liquid chromatography × size-exclusion chromatography platform with ultraviolet spectroscopy and high-resolution mass spectrometry detection for the chemical characterization of complex polyesters.

BACKGROUND: Polyesters are applied in high-end products in many industrial applications, including resins and powder-coating applications. The characterization of the chemical heterogeneities within a polyester is of utmost interest to develop new products or improve existing applications. Unfortunately, characterization is a difficult task, as polyesters may feature distributions in end-group functionality, molecular weight, chemical composition, and degree of branching. Currently, no analytical method can characterize all these interdependent distributions in a single analysis. RESULTS: We report the use of comprehensive normal-phase liquid chromatography × size-exclusion chromatography hyphenated with ultraviolet-light spectroscopy and high-resolution mass spectrometry in parallel (NPLC × SEC-UV/HRMS) to characterize polyesters according to their end-group-functionality and molecular-weight distributions. The chemical composition can be measured with HRMS, while relative quantitation can be performed with UV detection. A supercharging agent was used during ionization allowing to extend the molecular-weight range of the detected chemical species. SIGNIFICANCE: The presented platform allows characterization of polyesters with varying fractions of carboxyl or hydroxyl end-group functionalities and varying distributions of molecular weight, degree of branching, and chemical compositions. The number-average and weight-average molar masses are obtained in the same analysis. This information cannot be obtained by any one-dimensional technique. The developed NPLC × SEC-UV/HRMS platform is a valuable tool for characterizing polyesters in an industrial setting.

A quantitative method for aquaporin-1 protein using magnetic preconcentration and probe-based immunoassay coupling to inductively coupled plasma mass spectrometry in urine analysis.

BACKGROUND: Aquaporin-1 (AQP1) protein plays a crucial role in intracellular and extracellular water homeostasis and fluid transport in organs and tissues associated with diverse life activities and is extremely abundant in the kidney. Accurate detection of AQP1 in urine can be applied as screening of early-stage disease. Application of magnetic preconcentration and probe-based signal amplification strategy coupling to inductively coupled plasma mass spectrometry (ICP-MS) is a more accurate, sensitive and specific detection method for AQP1 in complex biological samples compared to conventional methods. RESULTS: We described an element-labelling strategy based on magnetic preconcentration and probe-based immunoassay coupling to ICP-MS detection. The magnetic beads (MBs) modified with epoxy groups were capable of enriching AQP1 proteins and separating them from complex matrices. The probe constructed by conjugating anti-AQP1 antibody molecules on the surface of gold nanoparticles could specifically recognize AQP1 proteins attached on MBs and be analyzed by ICP-MS. The concentration of AQP1 protein could be precisely quantified and amplified by 14,000 times through the corresponding signal of Au atoms. This assay for AQP1 protein quantification achieved a detection limit down to 0.023 ng mL-1, a broad linear calibration curve between 0.3 ng mL-1 and 30 ng mL-1, as well as outstanding specificity. SIGNIFICANCE: The proposed method was successfully applied to detect AQP1 protein in human urine samples, showing the potential for its applications concerning accurate AQP1 quantification. It can also screen a wide range of proteins provided the antibodies specific to these target proteins are available.

Human phase-I metabolism of three synthetic cannabinoids bearing a cumyl moiety and a cyclobutyl methyl or norbornyl methyl tail: Cumyl-CBMEGACLONE, Cumyl-NBMEGACLONE, and Cumyl-NBMINACA.

Synthetic cannabinoid receptor agonists (SCRAs) continue to show high prevalence on the new psychoactive substances drug market. Around 2019-2020, new SCRAs bearing a cumyl moiety emerged: Cumyl-CBMEGACLONE and Cumyl-NBMEGACLONE, carrying a cyclobutyl methyl (CBM) and a norbornyl methyl moiety (NBM) attached to the γ-carbolinone core. These were followed by Cumyl-NBMINACA, the indazole carboxamide analog of Cumyl-NBMEGACLONE. The study aimed at evaluating the human phase-I metabolism of these compounds and at identifying suitable urinary markers to prove their consumption. After enzymatic hydrolysis, 14 authentic urine samples (eight for Cumyl-CBMEGACLONE, four for Cumyl-NBMEGACLONE, and two for Cumyl-NBMINACA) were analyzed by liquid chromatography-quadrupole time-of-flight mass spectrometry. Results were compared with in vitro metabolites generated by pooled human liver microsomes incubation. Fifteen human phase-I metabolites were identified for Cumyl-CBMEGACLONE, nine for Cumyl-NBMEGACLONE, and thirteen for Cumyl-NBMINACA. The main in vivo metabolites were built by monohydroxylation, dihydroxylation, or trihydroxylation. The following urinary biomarkers are suggested for detecting the consumption of the investigated SCRAs: products of monohydroxylation at the CBM and at the core for Cumyl-CBMEGACLONE; two products of monohydroxylation at the norbonyl methyl tail for Cumyl-NBMEGACLONE; and metabolites built by dihydroxylation at the NBM substructure and by an additional hydroxylation at the cumyl moiety for Cumyl-NBMINACA.

On the Topotactic Phase Transition Achieving Superconducting Infinite-Layer Nickelates.

Topotactic reduction is critical to a wealth of phase transitions of current interest, including synthesis of the superconducting nickelate Nd0.8Sr0.2NiO2, reduced from the initial Nd0.8Sr0.2NiO3/SrTiO3 heterostructure. Due to the highly sensitive and often damaging nature of the topotactic reduction, however, only a handful of research groups have been able to reproduce the superconductivity results. A series of in situ synchrotron-based investigations reveal that this is due to the necessary formation of an initial, ultrathin layer at the Nd0.8Sr0.2NiO3 surface that helps to mediate the introduction of hydrogen into the film such that apical oxygens are first removed from the Nd0.8Sr0.2NiO3 / SrTiO3 (001) interface and delivered into the reducing environment. This allows the square-planar / perovskite interface to stabilize and propagate from the bottom to the top of the film without the formation of interphase defects. Importantly, neither geometric rotations in the square planar structure nor significant incorporation of hydrogen within the films is detected, obviating its need for superconductivity. These findings unveil the structural basis underlying the transformation pathway and provide important guidance on achieving the superconducting phase in reduced nickelate systems.

Stability in human serum and plasma of the HIV peptide drug candidate CIGB-210 and improved variants.

The peptide CIGB-210 inhibits HIV replication, inducing a rearrangement of vimentin intermediate filaments. The assessment of the in vitro serum and plasma stability of this peptide is important to develop an optimal pharmacological formulation. A half-life of 17.68 ± 0.59 min was calculated for CIGB-210 in human serum by reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry (MS). Eight metabolites of CIGB-210 were identified with this methodology, all of them lacking the N-terminal moiety. A previously developed CIGB-210 in-house competitive ELISA was used to compare the stability of CIGB-210 derivatives containing either D-amino acids, acetylation at the N-terminus, or both modifications. The half-life of CIGB-210 in serum was five times higher when measured by ELISA than by HPLC/MS, and twice higher in plasma as compared to serum. The substitution of D-asparagine on position 6 doubled the half-life, while D-amino acids on positions 8 and 9 did not improve the stability. The acetylation of the N-terminus resulted in a 24-fold more stable peptide in plasma. The positive effect of N-terminal acetylation on CIGB-210 serum stability was confirmed by the HPLC/MS method, as the half-life of the peptide was not reached after 2 h of incubation, which represents more than a 6.8-fold increase in the half-life with respect to the original peptide.

A Decade of Computational Mass Spectrometry from Reference Spectra to Deep Learning.

Computational methods are playing an increasingly important role as a complement to conventional data evaluation methods in analytical chemistry, and particularly mass spectrometry. Computational mass spectrometry (CompMS) is the application of computational methods on mass spectrometry data. Herein, advances in CompMS for small molecule chemistry are discussed in the areas of spectral libraries, spectrum prediction, and tentative structure identification (annotation): Automatic spectrum curation is facilitating the expansion of openly available spectral libraries, a crucial resource both for compound annotation directly and as a resource for machine learning algorithms. Spectrum prediction and molecular fingerprint prediction have emerged as two key approaches to compound annotation. For both, multiple methods based on classical machine learning and deep learning have been developed. Driven by advances in deep learning-based generative chemistry, de novo structure generation from fragment spectra is emerging as a new field of research. This review highlights key publications in these fields, including our approaches RMassBank (automatic spectrum curation) and MSNovelist (de novo structure generation).

MSIGen: An Open-Source Python Package for Processing and Visualizing Mass Spectrometry Imaging Data.

Mass spectrometry imaging (MSI) provides information about the spatial localization of molecules in complex samples with high sensitivity and molecular selectivity. Although point-wise data acquisition, in which mass spectra are acquired at predefined points in a grid pattern, is common in MSI, several MSI techniques use line-wise data acquisition. In line-wise mode, the imaged surface is continuously sampled along consecutive parallel lines and MSI data are acquired as a collection of line scans across the sample. Furthermore, aside from the standard imaging mode in which full mass spectra are acquired, other acquisition modes have been developed to enhance molecular specificity, enable separation of isobaric and isomeric species, and improve sensitivity to facilitate the imaging of low abundance species. These methods, including MS/MS-MSI in both MS2 and MS3 modes, multiple-reaction monitoring (MRM)-MSI, and ion mobility spectrometry (IMS)-MSI have all demonstrated their capabilities, but their broader implementation is limited by the existing MSI analysis software. Here, we present MSIGen, an open-source Python package for the visualization of MSI experiments performed in line-wise acquisition mode containing MS1, MS2, MRM, and IMS data, which is available at https://github.com/LabLaskin/MSIGen. The package supports multiple vendor-specific and open-source data formats and contains tools for targeted extraction of ion images, normalization, and exportation as images, arrays, or publication-style images. MSIGen offers multiple interfaces, allowing for accessibility and easy integration with other workflows. Considering its support for a wide variety of MSI imaging modes and vendor formats, MSIGen is a valuable tool for the visualization and analysis of MSI data.

Ethion food poisoning outbreak in Pereira, Colombia, 2022.

INTRODUCTION: Ethion is an organophosphate used as an acaricide and insecticide, that is restricted worldwide. In Colombia, pesticide poisoning is the third most common cause of chemical intoxication. On 9 October 2022, an outbreak of ethion poisoning occurred in Pereira. The aim of this study was to describe the clinical and epidemiological characteristics of the outbreak. METHODS: This is a descriptive study of an outbreak of organophosphate poisoning. The onset of symptoms occurred on 9 October 2022, following the consumption of empanadas. Information was collected on sociodemographic characteristics and clinical manifestations, as well as from paraclinical examinations. Data were obtained from clinical histories, field epidemiological investigations, and inspection visits. Food samples were collected for analysis by gas chromatography-mass spectrometry. Attack rates, proportions, and measures of central tendency, dispersion, and position were calculated. RESULTS: The case definition was met by 37 individuals with a median age of 30 years; all presented with muscarinic symptoms, 29 patients presented with nicotinic symptoms, and 20 patients presented with neurological symptoms. Males were the most affected (57%), and the most common time of symptom onset was 10:00 am. Twenty-three patients (62%) required intensive care unit admission, of whom 14 (38%) required mechanical ventilation. No deaths were reported. Erythrocyte acetylcholinesterase activity was reduced in all patients. Ethion was detected in mass-prepared maize and empanadas at concentrations greater than 0.1 mg/kg. The consumption of empanadas was identified as the common source. DISCUSSION: In Colombia, pesticide poisonings are the third most common type of poisoning caused by chemical substances reported to the National Health Institute through the National Public Health Surveillance System. In the present outbreak, ethion was in empanadas, likely due to contamination of cooking oil. CONCLUSIONS: We describe a large ethion-contaminated food poisoning outbreak reported in Colombia. The main symptoms were muscarinic, and the main treatment measures employed were atropine and respiratory support. Increased awareness of pesticide poisoning and training for food handlers are needed.