Metabolism of a fungicide propiconazole by Cunninghamella elegans ATCC36112.

The metabolic breakdown of propiconazole by fungi was examined, and it was found that the microbial model (Cunninghamella elegans ATCC36112) efficiently degrades the triazole fungicide propiconazole through the action of cytochrome P450. This enzyme primarily facilitates the oxidation and hydrolysis processes involved in phase I metabolism. We observed major metabolites indicating hydroxylation/oxidation of propyl groups of propiconazole. Around 98% of propiconazole underwent degradation within a span of 3 days post-treatment, leading to the accumulation of five metabolites (M1-M5). The experiments started with a preliminary identification of propiconazole and its metabolites using GC-MS. The identified metabolites were then separated and identified by in-depth analysis using preparative UHPLC and MS/MS. The metabolites of propiconazole are M1 (CGA-118245), M2(CGA-118244), M3(CGA-136735), M4(GB-XLIII-42-1), and M5(SYN-542636). To further investigate the role of key enzymes in potential fungi, we treated the culture medium with piperonyl butoxide (PB) and methimazole (MZ), and then examined the kinetic responses of propiconazole and its metabolites. The results indicated a significant reduction in the metabolism rate of propiconazole in the medium treated with PB, while methimazole showed weaker inhibitory effects on the metabolism of propiconazole in the fungus C. elegans.

Late Parasitological Failure and Subsequent Isolated Gametocytemia of Uncomplicated Plasmodium falciparum Malaria in a Returned Traveler From Ghana, 2023.

Herein, we report a case of uncomplicated falciparum malaria with late parasitological failure in a 45-year-old businessman returning from Ghana. The patient visited the emergency department with high fever, headache, and dizziness. He traveled without antimalarial chemoprophylaxis. Laboratory tests led to the diagnosis of uncomplicated falciparum malaria with an initial density of 37,669 parasites per µL of blood (p/µL). The patient was treated with intravenous artesunate followed by atovaquone/proguanil. He was discharged with improved condition and decreased parasite density of 887 p/µL. However, at follow-up, parasite density increased to 7,630 p/µL despite the absence of any symptoms. Suspecting treatment failure, the patient was administered intravenous artesunate and doxycycline for seven days and then artemether/lumefantrine for three days. Blood smear was negative for asexual parasitemia after re-treatment but positive for gametocytemia until day 101 from the initial diagnosis. Overall, this case highlights the risk of late parasitological failure in patients with imported uncomplicated falciparum malaria.

Prognosis Following Sustained Virologic Response in Korean Chronic Hepatitis C Patients Treated with Sofosbuvir-Based Treatment: Data from a Multicenter Prospective Observational Study up to 7 Years.

Background and Objectives: Chronic hepatitis C (CHC) can be cured with direct-acting antiviral (DAA) therapy. In Korea, sofosbuvir (SOF) and ledipasvir (LDV)/SOF were launched in 2016. Patients who achieve a sustained virologic response (SVR) following DAA treatment are predicted to have a favorable prognosis. Nevertheless, little is known regarding the prognosis of Korean CHC patients who receive SOF-based treatment and achieve SVR. Therefore, the purpose of this study was to look into the long-term outcomes for these patients. Materials and Methods: This was a prospective, multicenter observational study. CHC patients were enrolled who, following SOF or LDV/SOF treatment, had achieved SVR. The last day for follow-up was December 2023. The primary endpoint was HCC occurrence, which was checked at least once per year. Results: A total of 516 patients were included in this analysis, with a median follow-up duration of 39.0 months. Among them, 231 were male patients (44.8%), with a median age of 62.0 years. Genotypes were 1 (90, 17.4%), 2 (423, 82.0%), and 3 (3, 0.6%). The combination of SOF plus ribavirin was the most common treatment (394, 76.4%). In total, 160 patients were cirrhotic (31.0%), and the mean Child-Pugh score was 5.1. Within a maximum of 7 years, 21 patients (4.1%) developed HCC. Patients with HCC were older (69 vs. 61 years, p = 0.013) and had a higher cirrhosis incidence (81.0 vs. 28.9%, p < 0.001), higher AFP (6.0 vs. 3.3, p = 0.003) and higher APRI (0.8 vs. 0.5, p = 0.005). Age over 65 (p = 0.016) and cirrhosis (p = 0.005) were found to be significant risk factors for HCC by Cox regression analysis. Conclusions: Patients who achieved SVR with SOF-based treatment had a relatively favorable prognosis. However, the risk of HCC was not eliminated, especially in older and cirrhotic patients. Therefore, routine follow-up, surveillance, and early treatment are required.

Antibiotic prescription patterns during last days of hospitalized patients with advanced cancer: the role of palliative care consultation.

OBJECTIVES: Issues regarding antibiotic use in end-of-life patients with advanced cancer present a challenging ethical dilemma in academic referral centres. This study aimed to investigate the role of palliative care consultation on antibiotic prescription patterns among hospitalized patients with advanced cancer during their last days of life. METHODS: This retrospective cohort study included adult patients with metastatic solid cancer admitted to a tertiary referral hospital for at least 4 days and subsequently died and who were given antibiotics 4 days before death between January 2018 and December 2021. Patients were divided into palliative care consultation (PC) and non-consultation (non-PC) groups. The outcomes were the proportion of patients who received antibiotic combination treatment, antibiotic escalation and antibiotic de-escalation within 3 days of death. Propensity score analysis with the inverse probability of the treatment weighting method was used to compare the outcomes. RESULTS: Among the 1177 patients enrolled, 476 (40.4%) received palliative care consultation and 701 (59.6%) did not. The PC group received considerably less antibiotic combination treatment (49.0% versus 61.1%, adjusted OR: 0.69, 95% CI: 0.53-0.90, P = 0.006) and antibiotic escalation (15.8% versus 34.8%, adjusted OR: 0.41, 95% CI: 0.30-0.57, P < 0.001) than the non-PC group. Additionally, the PC group reported significantly higher antibiotic de-escalation (30.7% versus 17.4%, adjusted OR: 1.74, 95% CI: 1.28-2.36, P < 0.001). CONCLUSION: Receiving palliative care consultation may minimize aggressive antibiotic prescription patterns in the last days of patients with advanced cancer in an academic referral centre setting.

Metabolism of an insecticide fipronil by soil fungus Cunninghamella elegans ATCC36112.

In this study, the metabolic pathway of the phenylpyrazole insecticide fipronil in Cunninghamella elegans (C. elegans) was investigated. Approximately 92% of fipronil was removed within 5 days, and seven metabolites were accumulated simultaneously. The structures of the metabolites were completely or tentatively identified by GC-MS and 1H, 13C NMR. To determine the oxidative enzymes involved in metabolism, piperonyl butoxide (PB) and methimazole (MZ) were used, and the kinetic responses of fipronil and its metabolites were determined. PB strongly inhibited fipronil metabolism, while MZ weakly inhibited its metabolism. The results suggest that cytochrome P450 (CYP) and flavin-dependent monooxygenase (FMO) may participate in fipronil metabolism. Integrated metabolic pathways can be inferred from the control and inhibitor experiments. Several novel products from the fungal transformation of fipronil were identified, and similarities between C. elegans transformation and mammalian metabolism of fipronil were compared. Therefore, these results will help to gain insight into the fungal degradation of fipronil and potential applications in fipronil bioremediation. At present, microbial degradation of fipronil is the most promising approach and maintains environmental sustainability. In addition, the ability of C. elegans to mimic mammalian metabolism will assist in illustrating the metabolic fate of fipronil in mammalian hepatocytes and assess its toxicity and potential adverse effects.

Metabolic pathway of tebuconazole by soil fungus Cunninghamella elegans ATCC36112.

Tebuconazole is the most widely used fungicide in agriculture. Due to its long half-life, tebuconazole residues can be found in the environment media such as in soil and water bodies. Here, the metabolic pathway of tebuconazole was studied in Cunninghamella elegans (C. elegans). Approximately 98% of tebuconazole was degraded within 7 days, accompanied by the accumulation of five metabolites. The structures of the metabolites were completely or tentatively identified by gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To identify representative oxidative enzymes that may be involved in the metabolic process, treatment with piperonyl butoxide (PB) and methimazole (MZ) was performed. PB had a strong inhibitory effect on the metabolic reactions, while MZ had a weak inhibitory effect. The results suggest that cytochrome P450 (CYP) and flavin-dependent monooxygenase are involved in the metabolism of tebuconazole. Based on the results, we propose a metabolic pathway for the fungal metabolism of tebuconazole. Data are of interest to gain insight into the toxicological effects of tebuconazole and for tebuconazole bioremediation.

Biodegradation and metabolic pathway of quinalphos by Cunninghamella elegans ATCC36112.

Quinalphos is a long-term, wide-spectrum organophosphate insecticide with residual problems in the natural environment. Cunninghamella elegans (C. elegans) is a member of Mucoromycotina. Since the degradation products of its exogenous compounds are similar to those of mammals, it is often used to simulate the metabolism pathways of mammals. In this study, the detailed metabolic pathways of quinalphos were investigated with C. elegans. Quinalphos was degraded by 92% in 7 days, while ten metabolites were produced. The metabolites were analyzed and identified by GC-MS. To determine the responsible enzymes in quinalphos metabolism, piperonyl butoxide (PB) and methimazole included in the culture flasks, and the kinetic responses of quinalphos and its metabolites by C. elegans were measured. Results indirectly demonstrated that cytochrome P450 monooxygenases were involved in the metabolism of quinalphos, but that methimazole inhibited the metabolism less efficiently. Comprehensive metabolic pathways can be deduced from the detailed analysis of metabolite profiles in control and inhibitor assays.

MELD-GRAIL-Na Is a Better Predictor of Mortality Than MELD in Korean Patients with Cirrhosis.

Background and Objectives: The Child-Pugh (CP) score and Model for End-Stage Liver Disease (MELD) are classical systems for predicting mortality in patients with liver cirrhosis (LC). The MELD-GFR assessment in liver disease-sodium (MELD-GRAIL-Na) was designed to better reflect renal function and, therefore, provide better mortality predictions. This study aimed to compare the prediction accuracy of MELD-GRAIL-Na compared to CP and MELD in predicting short-term (1- and 3-month) mortality in Korean patients. Materials and Methods: Medical records of patients with LC admitted to the Konkuk University Hospital from 2015 to 2020 were retrospectively reviewed. Predictive values of the CP, MELD, and MELD-GRAIL-Na for 1-month and 3-month mortality were calculated using the area under the receiver operating curve (AUROC) and were compared using DeLong's test. Results: In total, 1249 patients were enrolled; 102 died within 1 month, and 146 within 3 months. AUROCs of CP, MELD, and MELD-GRAIL-Na were 0.831, 0.847, and 0.857 for 1-month mortality and 0.837, 0.827, and 0.835 for 3-month mortality, respectively, indicating no statistical significance. For patients with CP classes B and C, AUROCs of CP, MELD, and MELD-GRAIL-Na were 0.782, 0.809, and 0.825 for 1-month mortality and 0.775, 0.769, and 0.786 for 3-month mortality, respectively. There was a significant difference between CP and MELD-GRAIL-Na in predicting 1-month mortality (p = 0.0428) and between MELD and MELD-GRAIL-Na in predicting 1-month (p = 0.0493) and 3-month mortality (p = 0.0225). Conclusions: Compared to CP and MELD, MELD-GRAIL-Na was found to be a better and more useful system for evaluating short-term (1- and 3-month) mortality in Korean patients with cirrhosis, especially those with advanced cirrhosis (CP class B and C).

Prognosis of Patients with Chronic Hepatitis C Genotype 1b Infection Treated Using Daclatasvir/Asunaprevir after Sustained Virologic Response: A 6-Year Multicenter Prospective Observational Study.

Aim and Objectives: Direct-acting antiviral (DAA) therapy can cure chronic hepatitis C (CHC), and daclatasvir (DCV)/asunaprevir (ASV) was the first interferon-free DAA therapy introduced in Korea. Patients who achieve sustained virologic response (SVR) after DAA treatment are expected to have good prognoses. Therefore, in this study, we aimed to investigate the prognosis of these patients. Materials and Methods: This multicenter prospective observational study included patients with CHC who achieved SVR after DCV/ASV treatment. The primary endpoint was hepatocellular carcinoma (HCC) occurrence, which was reviewed annually. Results: We included 302 patients (median follow-up duration: 38 [16.5-60.0] months; median age: 58 [49-67] years) in the study. Cirrhosis was observed in 103 patients (34.1%), and the median Child-Pugh score was 5.0. HCC occurred in 16 patients (5.3%) within six years post-SVR; these patients were older and had higher cirrhosis prevalence, alpha-fetoprotein levels, and fibrosis-4 index scores than did those without HCC development. Cox proportional hazards analysis revealed that age > 71 years (p = 0.005) and cirrhosis (p = 0.035) were significant risk factors for HCC occurrence. Conclusions: Although the prognoses of patients who achieved SVR with DCV/ASV therapy were generally good, the risk for HCC was present, especially in older patients and in those with cirrhosis. Hence, early treatment at younger ages and regular follow-up surveillance after achieving SVR are warranted.

Structure and substrate specificity determinants of NfnB, a dinitroaniline herbicide-catabolizing nitroreductase from Sphingopyxis sp. strain HMH.

Nitroreductases are emerging as attractive bioremediation enzymes, with substrate promiscuity toward both natural and synthetic compounds. Recently, the nitroreductase NfnB from Sphingopyxis sp. strain HMH exhibited metabolic activity for dinitroaniline herbicides including butralin and pendimethalin, triggering the initial steps of their degradation and detoxification. However, the determinants of the specificity of NfnB for these herbicides are unknown. In this study, we performed structural and biochemical analyses of NfnB to decipher its substrate specificity. The homodimer NfnB is a member of the PnbA subgroup of the nitroreductase family. Each monomer displays a central α + ß fold for the core domain, with a protruding middle region and an extended C-terminal region. The protruding middle region of Val75-Tyr129 represents a structural extension that is a common feature to members of the PnbA subgroup and functions as an opening wall connecting the coenzyme FMN-binding site to the surface, therefore serving as a substrate binding site. We performed mutational, kinetic, and structural analyses of mutant enzymes and found that Tyr88 in the middle region plays a pivotal role in substrate specificity by determining the dimensions of the wall opening. The mutation of Tyr88 to phenylalanine or alanine caused significant changes in substrate selectivity toward bulkier dinitroaniline herbicides such as oryzalin and isopropalin without compromising its activity. These results provide a framework to modify the substrate specificity of nitroreductase in the PnbA subgroup, which has been a challenging issue for its biotechnological and bioremediation applications.

The impact of palliative care consultation on reducing antibiotic overuse in hospitalized patients with terminal cancer at the end of life: a propensity score-weighting study.

OBJECTIVES: A substantial number of hospitalized patients with terminal cancer at the end-of-life phase receive antibiotics, even with imminent death. We evaluated the impact of palliative care consultation on antibiotic use in hospitalized patients with terminal cancer during the end-of-life phase. METHODS: We identified adult patients with metastatic solid cancer who died at a tertiary medical centre in Seoul, Republic of Korea, following at least 4 days of hospitalization (January 2018-December 2020). Patients were divided into palliative and non-palliative care consultation groups. Propensity score-weighted, multivariable logistic regression analysis was used to compare the proportion of patients receiving antibiotics within 3 days before death between the two groups. RESULTS: Among 1143 patients analysed, 940 (82.2%) received antibiotics within 3 days before death. The proportion of patients receiving antibiotics was significantly lower (propensity score-weighted P < 0.001) in the palliative care consultation group (344/468; 73.5%) than in the non-palliative care consultation group (596/675; 88.3%). The decrease in the proportion of patients receiving antibiotics in the palliative care consultation group was significant for a carbapenem (42.4% versus 22.4%; P < 0.001), a glycopeptide (23.3% versus 11.1%; P < 0.001) and a quinolone (30.5% versus 19.4%; P = 0.012). In the multivariable logistic regression analysis, receiving palliative care consultation (adjusted OR 0.46, 95% CI 0.33-0.65; P < 0.001) was independently associated with reduced antibiotic use during the end-of-life phase. CONCLUSIONS: Palliative care consultation may reduce aggressive antibiotic use in hospitalized patients with terminal cancer during the end-of-life phase.

Occupational exposure and risk assessment for agricultural workers of thiamethoxam in vineyards.

Dermal & inhalation exposure was examined and according to these results, risk assessment of agricultural workers to thiamethoxam was performed during pesticide mixing/loading and hand-held sprayer application (11 replicates, each of about 1000 L of spray suspension) in vineyards. For the whole body dosimetry (WBD), clothing (Outer and inner), gauze, and nitrile gloves were analyzed to determine dermal exposure using whole-body dosimetry exposure protocol. The inhalation exposure was measured using a glass fiber filter with an IOM sampler. Analytical method validation of exposure matrices was evaluated including the field recovery and breakthrough test. The dermal exposure amount during mixing/loading was 0.163 mg (0.0004% of the total mixed/loaded active ingredient [a.i.]), whereas there was no inhalation exposure. The gloves (0.154 mg, 94.5%) were the most exposed body parts followed by the chest and stomach (0.009 mg, 5.5%). During application, the dermal and inhalation exposure amounts were 32.3 mg (0.07% of the total applied a.i.) and 10.8 µg (2.4 × 10-6% of the total applied a.i), respectively. The shin (35.1%) had the highest exposure to pesticides, followed by the chest & stomach (15.6%) and pelvis (12.6%). In case of mixing/loading, the amounts of actual dermal exposure (ADE) and actual inhalation exposure (AIE) were 0.0 and 0.0 µg/day, while those of ADE and AIE were 4707.6 and 15.8 µg/day for application. In risk assessment of the two different scenarios, the risk index was much lower than 1 (mixing/loading:0.000, application:0.014), indicating that vineyard workers are at low risk of thiamethoxam exposure. To determine the validity of the risk assessment using WBD method, the urinary metabolite was analyzed. Comparison of biomonitoring data and WBD exposure data show a reliable correlation (r = 0.885, p = 0.0003), suggesting that these are suitable methods to estimate exposure.

Computational Modeling and Imaging of the Intracellular Oxygen Gradient.

Computational modeling can provide a mechanistic and quantitative framework for describing intracellular spatial heterogeneity of solutes such as oxygen partial pressure (pO2). This study develops and evaluates a finite-element model of oxygen-consuming mitochondrial bioenergetics using the COMSOL Multiphysics program. The model derives steady-state oxygen (O2) distributions from Fickian diffusion and Michaelis-Menten consumption kinetics in the mitochondria and cytoplasm. Intrinsic model parameters such as diffusivity and maximum consumption rate were estimated from previously published values for isolated and intact mitochondria. The model was compared with experimental data collected for the intracellular and mitochondrial pO2 levels in human cervical cancer cells (HeLa) in different respiratory states and under different levels of imposed pO2. Experimental pO2 gradients were measured using lifetime imaging of a Förster resonance energy transfer (FRET)-based O2 sensor, Myoglobin-mCherry, which offers in situ real-time and noninvasive measurements of subcellular pO2 in living cells. On the basis of these results, the model qualitatively predicted (1) the integrated experimental data from mitochondria under diverse experimental conditions, and (2) the impact of changes in one or more mitochondrial processes on overall bioenergetics.

4-Coumarate:coenzyme A ligase isoform 3 from Piper nigrum (Pn4CL3) catalyzes the CoA thioester formation of 3,4-methylenedioxycinnamic and piperic acids.

Black pepper, dried green fruit of Piper nigrum L., is a household spice most popular in the world. Piperine, the pungency compound of black pepper, is proposed to partially arise from phenylpropanoid pathway. In the biosynthesis of piperine, 4-coumarate:CoA ligase (4CLs) must play a pivotal role in activating intermediate acids to corresponding CoA thioesters to serve as substrates. Based on transcriptome data, we isolated three P. nigrum 4CL isoforms (Pn4CL1, -2, and -3) from unripe peppercorn. These Pn4CLs were expressed in E. coli for in vitro enzyme assay with putative substrates, namely cinnamic, coumaric, ferulic, piperonylic, 3,4-methylenedioxycinnamic (3,4-MDCA), and piperic acids. Phylogenetic analysis and substrate usage study indicated that Pn4CL1, active towards coumaric and ferulic acids, belongs to class I 4CL for lignin synthesis. Pn4CL2 was a typical cinnamate-specific coumarate:CoA ligase-like (CLL) protein. The Pn4CL3, as class II enzyme, exhibited general 4CL activity towards coumaric and ferulic acids. However, Pn4CL3 was also active towards piperonylic acid, 3,4-MDCA, and piperic acid. Pn4CL3 possessed ∼2.6 times higher catalytic efficiency (kcat/KM) towards 3,4-MDCA and piperic acid than towards coumaric and ferulic acids, suggesting its specific role in piperine biosynthesis. Different substrate preference among the Pn4CL isoforms can be explained by 3-dimensional protein structure modeling, which demonstrated natural variants in amino acid residues of binding pocket to accommodate different substrates. Quantitative PCR analysis of these isoforms indicated that Pn4CL1 transcript level was highest in the roots whereas Pn4CL2 in the fruits and Pn4CL3 in the leaves.

Determination of Anthelmintic and Antiprotozoal Drug Residues in Fish Using Liquid Chromatography-Tandem Mass Spectrometry.

The objective of this study is to develop a comprehensive and simple method for the simultaneous determination of anthelmintic and antiprotozoal drug residues in fish. For sample preparation, we used the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method with a simple modification. The sample was extracted with water and 1% formic acid in acetonitrile/methanol (MeCN/MeOH) (95:5, v/v), followed by phase separation (salting out) with MgSO4 and NaCl (4:1, w/w). After centrifugation, an aliquot of the extract was purified by dispersive solid-phase extraction (d-SPE) prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was validated at three concentration levels for all matrices, in accordance with the Codex guidelines (CAC/GL-71). Quantitative analysis was performed using the method of matrix-matched calibration. The recoveries were between 60.6% and 119.9%, with coefficients of variation (CV) <30% for all matrices. The limit of quantitation (LOQ) of the method ranged from 0.02 µg kg-1 to 4.8 µg kg-1 for all matrices. This comprehensive method can be used for the investigation of both anthelmintic and antiprotozoal drugs belonging to different chemical families in fishery products.

Crystal structure of the indole-3-acetic acid-catabolizing enzyme DAO1 from Arabidopsis thaliana.

Indole-3-acetic acid (IAA), the major form of the plant hormone auxin, regulates almost every aspect of plant growth and development. Therefore, auxin homeostasis is an essential process in plants. Different metabolic routes are involved in auxin homeostasis, but the catabolic pathway has remained elusive until recent studies identified DIOXYGENASE FOR AUXIN OXIDATION (DAO) from rice and Arabidopsis thaliana. DAO, a member of the 2-oxoglutarate/Fe(II)-dependent oxygenase (2ODO) family, constitutes a major enzyme for IAA catabolism. This enzyme catalyzes, with the cosubstrate 2-oxoglutarate, the conversion of IAA into 2-oxoindole-3-acetic acid, a functionally inactive oxidative product of IAA. Here, we report a crystal structure of the unliganded DAO1 from A. thaliana (AtDAO1) and its complex with 2-oxoglutarate. AtDAO1 is structurally homologous with members of the 2ODO family but exhibits unique features in the prime substrate IAA binding site. We provide structural analyses of a putative binding site for IAA, supporting possible structural determinants for the substrate specificity of AtDAO1 toward IAA.

An Easy-to-Use Machine Learning Model to Predict the Prognosis of Patients With COVID-19: Retrospective Cohort Study.

BACKGROUND: Prioritizing patients in need of intensive care is necessary to reduce the mortality rate during the COVID-19 pandemic. Although several scoring methods have been introduced, many require laboratory or radiographic findings that are not always easily available. OBJECTIVE: The purpose of this study was to develop a machine learning model that predicts the need for intensive care for patients with COVID-19 using easily obtainable characteristics-baseline demographics, comorbidities, and symptoms. METHODS: A retrospective study was performed using a nationwide cohort in South Korea. Patients admitted to 100 hospitals from January 25, 2020, to June 3, 2020, were included. Patient information was collected retrospectively by the attending physicians in each hospital and uploaded to an online case report form. Variables that could be easily provided were extracted. The variables were age, sex, smoking history, body temperature, comorbidities, activities of daily living, and symptoms. The primary outcome was the need for intensive care, defined as admission to the intensive care unit, use of extracorporeal life support, mechanical ventilation, vasopressors, or death within 30 days of hospitalization. Patients admitted until March 20, 2020, were included in the derivation group to develop prediction models using an automated machine learning technique. The models were externally validated in patients admitted after March 21, 2020. The machine learning model with the best discrimination performance was selected and compared against the CURB-65 (confusion, urea, respiratory rate, blood pressure, and 65 years of age or older) score using the area under the receiver operating characteristic curve (AUC). RESULTS: A total of 4787 patients were included in the analysis, of which 3294 were assigned to the derivation group and 1493 to the validation group. Among the 4787 patients, 460 (9.6%) patients needed intensive care. Of the 55 machine learning models developed, the XGBoost model revealed the highest discrimination performance. The AUC of the XGBoost model was 0.897 (95% CI 0.877-0.917) for the derivation group and 0.885 (95% CI 0.855-0.915) for the validation group. Both the AUCs were superior to those of CURB-65, which were 0.836 (95% CI 0.825-0.847) and 0.843 (95% CI 0.829-0.857), respectively. CONCLUSIONS: We developed a machine learning model comprising simple patient-provided characteristics, which can efficiently predict the need for intensive care among patients with COVID-19.

Simultaneous Analysis of Fenthion and Its Five Metabolites in Produce Using Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.

A simultaneous analytical method for the organophosphorus insecticide fenthion and its five metabolites (fenthion oxon, fenthion oxon sulfoxide, fenthion oxon sulfone, fenthion sulfoxide, and fenthion sulfone) was developed based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Five matrices (brown rice, chili pepper, orange, potato, and soybean) were selected to validate the method. The target compounds were analyzed using positive electrospray ionization in the multiple reaction monitoring mode. For the best sensitivity in regard to the detector response, water and methanol containing formic acid (0.1%) were selected as the mobile phase. The optimum extraction efficiency was obtained through a citrate-buffered QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. Recovery tests were carried out at three spiking levels (n = 3). At all fortification levels, the accuracy and precision results were between 70% and 120% with a relative standard deviation of ≤15%. The limit of quantitation was 0.01 mg/kg, and the correlation coefficients (r2) of the matrix-matched calibration curves were >0.99. Significant signal suppression in the detector responses were observed for all matrices, suggesting that a compensation method, such as matrix-matched calibration, is required to provide accurate quantitative results. The applicability of the presented method was confirmed for the simultaneous analysis of fenthion and its metabolites in various crops.

Liquid Chromatography-Tandem Mass Spectrometry for the Simultaneous Analysis of 353 Pesticides in the Edible Insect Tenebrio molitor Larvae (Mealworms).

Tenebrio molitor larvae (mealworm) is an edible insect and is considered a future food. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a novel method for simultaneous analysis of 353 target analytes was developed and validated. Various sample preparation steps including "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) extraction conditions, number of acetonitrile-hexane partitions, and dispersive-solid phase extraction (dSPE) sorbents were compared, and the optimal conditions were determined. In the established method, 5 g of homogenized mealworms was extracted with acetonitrile and treated with QuEChERS EN 15662 salts. The crude extract was subjected to three rounds of acetonitrile-hexane partitioning, and the acetonitrile layer was cleaned with C18 dSPE. The final solution was matrix-matched and injected into LC-MS/MS (2 µL). For target analytes, the limits of quantitation (LOQs) were ≤10 µg/kg, and the correlation coefficient (r2) of calibration was >0.990. In recovery tests, more than 90% of the pesticides showed an excellent recovery range (70-120%) with relative standard deviation (RSD) ≤20%. For more than 94% of pesticides, a negligible matrix effect (within ±20%) was observed. The analytical method was successfully applied and used for the detection of three urea pesticides in 4 of 11 mealworm samples.

Dissipation of Herbicide Methiozolin and Its Metabolites in Aerobic Sediment-Water Systems.

Methiozolin is a novel herbicide for controlling annual bluegrass. After applying 14C labelled methiozolin in two sediment (clay loam and sand)-water systems under aerobic conditions, its distribution, half-life, and metabolites within 300 days were investigated. The mass balance ranged within 92.0%-104.4% of applied radioactivity (AR). Radioactivity in the water declined sharply from 94.4% to 0.5% AR, while in the sediment it increased to 83.9% AR at 14 days before declining to 9.1% AR. The volatiles were minimal (< 0.5% AR), and the evolved labelled CO2 accounted for up to ~ 33.4% AR. From Radio-HPLC analysis, labelled methiozolin in water decreased from 108.9% to 0% AR, while a maximum of 15.1% AR remained in the sediment at the end. Eight metabolites were detected, all at minor levels and accounting for < 5.5% AR. The half-life of labelled methiozolin in the total sediment-water systems were 50.7 and 38.7 days for clay loam and sand, respectively.