Neoadjuvant Chemotherapy or Adjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma.

BACKGROUND: Chemotherapy and chemoradiation have become essential adjuncts to improve the survival of patients with resectable esophageal squamous cell carcinoma (ESCC) in the perioperative period. Although preoperative treatment plus surgery is commonly used, controversy remains regarding the optimal treatment strategy for patients with locally advanced ESCC. METHODS: A retrospective review of clinical stage II and III ESCC patients who underwent esophagectomy at Henan Cancer Hospital between October 2014 and October 2017 was performed. The patients were divided into a neoadjuvant chemotherapy (NAC) group and an adjuvant chemotherapy (AC) group. Propensity score matching (PSM) was used to exclude confounders. Survival was estimated using Kaplan‒Meier analysis and compared by the log-rank test. The Cox proportional hazards regression model was used for both the univariate and multivariate analyses. RESULTS: A total of 684 patients were enrolled, including 365 (53.4%) patients in the NAC group. After PSM, 294 pairs of patients were left. NAC prolonged the OS (not reached versus 57.3 months, P = 0.002) and DFS (57.2 vs. 36.4 months, P = 0.010) and decreased the total rate of recurrence (50.1% vs. 59.2%, P = 0.025) and local recurrence (27.9% vs. 36.7%, P = 0.022) compared with AC. The multivariable analyses showed that NAC plus surgery modality was an independent predictor for improved OS (HR: 0.582, 95% CI: 0.467-0.786, P = 0.001). CONCLUSION: NAC plus surgery prolonged OS and DFS, and significantly decreased the total rate of recurrence compared with surgery plus AC in patients with clinical stage II and III ESCC.

Simultaneous Quantification of Biomarkers for Bis-(2-chloroethyl) Sulfide and 1,2-Bis(2-chloroethylthio) Ethane Exposure in Human Urine at Trace Exposure Levels by Gas Chromatography Tandem Mass Spectrometry via Simultaneous Incubation and Extraction.

Sulfur mustard [HD; bis-(2-chloroethyl) sulfide] and other analogues are a kind of highly toxic vesicant and have been prohibited by the Organization for the Prohibition of Chemical Weapons (OPCW) since 1997. Exposures to HD could generate several adducts in the plasma and hydrolysis products in the urine, which are widely applied as biomarkers to identify HD exposure in forensic analysis. Several methods have been developed for the detection of related biomarkers. However, most methods are based on complex derivatization, and not enough attention is paid to HD analogues. A modified and convenient analytical method reported herein includes simultaneous incubation and organic solvent extraction. The biomarkers such as thiodiglycol and 1,2-bis (2-hydroxyethylthio) are transferred to HD and 1,2-bis(2-chloroethylthio) ethane via hydrochloric acid at the appropriate temperature. The analytes are analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS) with 2-chloroethyl ethyl sulfide (2-CEES) applied as the internal standard. The interday and intraday study according to FDA rules has been achieved to evaluate the accuracy and precision of the method. The two targets are detected with a good linearity (R2 > 0.99) in the concentration ranges from 5 to 1000 ng/mL and 10 to 1000 ng/mL, with small relative standard deviations (RSD ≤6.62% and RSD ≤6.93%) and favorable recoveries between 90.3 and 107.3% and between 89.4 and 108.7%, respectively. The established method can be used for retrospective detection of sulfur mustards in biological samples and successfully applied in the biomedical proficiency testing organized by the OPCW.

A multicenter randomized, controlled clinical trial of adjuvant sintilimab for esophageal squamous cell carcinoma.

No adjuvant treatment has been established for patients who remain at high risk of recurrence and incidental pathologic lymph node metastasis for esophageal squamous cell carcinoma (ESCC). In this open-label, multicenter, phase III, randomized controlled trial, ESCC patients who did not achieve pathologic complete response after neoadjuvant chemotherapy plus surgery and clinical T1-2 N0 patients with incidental pathologic lymph node metastasis following initial surgery were randomized at a 2:1 ratio to receive either a sintilimab regimen or observational management (NCT05495152). The primary end point was disease-free survival for all randomized patients. The results of this randomized controlled trial addressed controversy regarding the survival benefits of adjuvant sintilimab treatment for patients with resected locally advanced ESCC. Clinical Trial Registration: NCT05495152 (ClinicalTrials.gov).

Inhibition of XPO1 with KPT-330 induces autophagy-dependent apoptosis in gallbladder cancer by activating the p53/mTOR pathway.

BACKGROUND: Gallbladder cancer (GBC) is a highly aggressive malignant cancer in the biliary system with poor prognosis. XPO1 (chromosome region maintenance 1 or CRM1) mediates the nuclear export of several proteins, mainly tumor suppressors. Thus, XPO1 functions as a pro-oncogenic factor. KPT-330 (Selinexor) is a United States Food and Drug Administration approved selective inhibitor of XPO1 that demonstrates good therapeutic effects in hematologic cancers. However, the function of XPO1 and the effect of KPT-330 have not been reported in GBC. METHODS: We analyzed the correlation between XPO1 expression levels by q-PCR and clinical features of GBC patients. Cell proliferation assays were used to analyze the in vitro antitumor effects of XPO1 inhibitor KPT-330. mRNA sequencing was used to explore the underlying mechanisms. Western blot was performed to explore the relationship between apoptosis and autophagy. The in vivo antitumor effect of KPT-330 was investigated in a nude mouse model of gallbladder cancer. RESULTS: We found that high expression of XPO1 was related to poor prognosis of GBC patients. We observed that XPO1 inhibitor KPT-330 inhibited the proliferation of GBC cells in vitro. Furthermore, XPO1 inhibitor KPT-330 induced apoptosis by reducing the mitochondrial membrane potential and triggering autophagy in NOZ and GBC-SD cells. Indeed, XPO1 inhibitor KPT-330 led to nuclear accumulation of p53 and activated the p53/mTOR pathway to regulate autophagy-dependent apoptosis. Importantly, KPT-330 suppressed tumor growth with no obvious toxic effects in vivo. CONCLUSION: XPO1 may be a promising prognostic indicator for GBC, and KPT-330 appears to be a potential drug for treating GBC effectively and safely.

Gemcitabine and XCT790, an ERRα inverse agonist, display a synergistic anticancer effect in pancreatic cancer.

Pancreatic cancer (PC) is one of the most fatal and chemoresistant malignancies with a poor prognosis. The current therapeutic options for PC have not achieved satisfactory results due to drug resistance. Therefore, it is urgent to develop novel treatment strategies with enhanced efficacy. This study sought to investigate the anticancer effect of gemcitabine and XCT790, an estrogen-related receptor alpha (ERRα) inverse agonist, as monotherapies or in combination for the treatment of PC. Here we demonstrated that the drug combination synergistically suppressed PC cell viability, its proliferative, migratory, invasive, apoptotic activities, and epithelial-to-mesenchymal transition (EMT), and it triggered G0/G1 cell cycle arrest and programmed cell death in vitro. In addition, in vivo assays using xenograft and mini-PDX (patient-derived xenograft) models further confirmed the synergistic antitumor effect between gemcitabine and XCT790 on PC. Mechanistically, gemcitabine and XCT790 suppressed PC by inhibiting ERRα and MEK/ERK signaling pathway. In conclusion, our current study demonstrated for the first time that gemcitabine combined with XCT790 displayed synergistic anticancer activities against PC, suggesting that their combination might be a promising treatment strategy for the therapy of PC.

Preoperative lymphocyte to C-reactive protein ratio as a new prognostic indicator in patients with resectable gallbladder cancer.

BACKGROUND: Inflammation is often related to cancer, and several inflammatory scores have been established to predict the prognosis of various types of cancer. Our study aimed to determine the prognostic value of the preoperative lymphocyte to C-reactive protein ratio (LCR) for predicting postoperative outcomes in patients with resectable gallbladder cancer (GBC). METHODS: A retrospective analysis of 104 GBC patients who received curative surgery at Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine from January 2000 to December 2016 was performed. A time-dependent receiver operating characteristic curve was constructed to evaluate the accuracy of different markers. Univariate and multivariate Cox proportional hazard models were used to define factors associated with overall survival. RESULTS: Among the assessed variables, the preoperative LCR showed the highest accuracy in predicting the overall survival of GBC patients (AUC: 0.736). Decreased preoperative LCR was significantly associated with advanced tumor stage, including tumor invasion (P = 0.018), lymph node metastasis (P = 0.011) and TNM stage (P = 0.022). A low preoperative LCR (cutoff threshold = 145.5) was an independent risk factor for overall survival in patients with resectable GBC (P < 0.001). CONCLUSIONS: The preoperative LCR is a novel and valuable prognostic indicator of postoperative survival in patients with resectable GBC.

Direct Acetonitrile-Assisted Trypsin Digestion Method Combined with LC-MS/MS-Targeted Peptide Analysis for Unambiguous Identification of Intact Ricin.

Ricin is a type II ribosome-inactivating protein toxin consisting of A and B chains linked by one interchain disulfide bond. Because of its high toxicity depending on both chains together, confirming the presence of both A and B chains of intact ricin is required during the investigation of the illegal production and application. Here, we report a novel and sensitive acetonitrile (ACN)-assisted trypsin digestion method for unambiguous identification of intact ricin by simultaneous detection of its marker peptides from A and B chains. Marker peptides were generated with a simple procedure by direct cleaving the native ricin at 45 °C for 4 h using Promega modified sequencing grade trypsin under the assistance of 10% ACN, and then directly analyzed by ultrahigh performance liquid chromatography tandem mass spectrometry. The type of trypsin was found to be one critical factor for cleavage of intact ricin based on a significant difference in the yields of specific peptides generated while using various types of trypsin. A low content of ACN in enzymatic buffer significantly reduced the digestion time from overnight to 4 h. There was commonly a better MS response of marker peptides when using the developed ACN-assisted trypsin digestion method than methanol-assisted trypsin digestion within the same 4 h. Totally, seven specific peptides with high sensitivity and specificity including three in the A-chain (TA7, TA11, and TA10) and four in the B-chain (TB6, TB14-ss-TB16, TB20, and TB18) were obtained as good marker peptides for unambiguous identification of intact ricin. The lowest concentration of native ricin for unambiguous identification was 20 ng/mL, in which three marker peptides from both the A-chain and B-chain could be measured with a minimum of three ion transitions. Combined with affinity enrichment, the developed approach was successfully applied for the measurement of intact ricin from the complicated matrix samples of the second, third, and fourth biotoxin exercises organized by the Organisation for the Prohibition of Chemical Weapons (OPCW). This study has provided a recommended detection method combined with one novel ACN-assisted trypsin digestion with MS for forensic unambiguous confirmation of trace ricin intact with high confidence.

Metal-Free Intramolecular [3+2] Cycloaddition of γ-Hydroxy Acetylenic Ketones with Alkynes for the Synthesis of Naphtho[1,2-c]furan-5-ones and Its Derivatization via a Selective C(sp2)-H Deuteration Reaction.

A metal-free intramolecular [3+2] cycloaddtion has been achieved by treating benzene-linked propynol-ynes with AcOH/H2O in a one-pot manner. The reaction provides greener, 100% atom-economic, highly regioselective, and more practical access to functionalized naphtho[1,2-c]furan-5-ones with valuable and versatile applications. The regioselective α-deuteration of naphtho[1,2-c]furan-5-ones has been also presented with excellent deuterium incorporation and chemical yields. Moreover, the fluorescent properties of naphtho[1,2-c]furan-5-one products have been investigated in solution.

Quantitative detection of ricin in beverages using trypsin/Glu-C tandem digestion coupled with ultra-high-pressure liquid chromatography-tandem mass spectrometry.

The toxic protein of ricin has drawn wide attention in recent years as a potential bioterrorism agent due to its high toxicity and wide availability. For the verification of the potential anti-terrorism activities, it is urgent for the quantification of ricin in food-related matrices. Here, a novel strategy of trypsin/Glu-C tandem digestion was introduced for quantitative detection of ricin marker peptides in several beverage matrices using isotope-labeled internal standard (IS)-mass spectrometry. The ricin in beverages was captured and enriched by biotinylated anti-ricin polyclonal antibodies conjugated to streptavidin magnetic beads. The purified ricin was cleaved using the developed trypsin/Glu-C tandem digestion method and then quantitatively detected by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with isotope-labeled T7A and TG11B selected as IS. The use of trypsin/Glu-C digestion allows shorter peptides, which are more suitable for MS detection, to be obtained than the use of single trypsin digestion. Under the optimized tandem digestion condition, except for T7A in the A-chain, two resulting specific peptides of TG13A, TG28A from the A-chain and two of TG11B, TG33B from the B-chain were chosen as novel marker peptides with high MS response. The uniqueness of the selected marker peptides allows for unambiguous identification of ricin among its homologous proteins in a single run. The MS response of the four novel marker peptides is increased by more than 10 times compared with that of individual corresponding tryptic peptides. Both the marker peptides of A-chain T7A and B-chain TG11B were selected as quantitative peptides based on the highest MS response among the marker peptides from their individual chains. The limit of detection (LOD) of ricin is 0.1 ng/mL in PBS and 0.5 ng/mL in either milk or orange juice. The linear range of calibration curves for ricin were 0.5-300 ng/mL in PBS, 1.0-400 ng/mL in milk, and 1.0-250 ng/mL in orange juice. The method accuracy ranged between 82.6 and 101.8% for PBS, 88.9-105.2% for milk, and 95.3-118.7% for orange juice. The intra-day and inter-day precision had relative standard deviations (%RSD) of 0.3-9.4%, 0.7-8.9%, and 0.2-6.9% in the three matrices respectively. Furthermore, whether T7A or TG11B is used as a quantitative peptide, the quantitative results of ricin are consistent. This study provides not only a practical method for the absolute quantification of ricin in beverage matrices but also a new strategy for the investigation of illegal use of ricin in chemical weapon verification tasks such as OPCW biotoxin sample analysis exercises.

Characterization of CD103+ CD8+ tissue-resident T cells in esophageal squamous cell carcinoma: may be tumor reactive and resurrected by anti-PD-1 blockade.

Though therapy that promotes anti-tumor response about CD8+ tumor-infiltrating lymphocytes (TILs) has shown great potential, clinical responses to CD8+ TILs immunotherapy vary considerably, largely because of different subpopulation of CD8+ TILs exhibiting different biological characters. To define the relationship between subpopulation of CD8+ TILs and the outcome of antitumor reaction, the phenotype and function of CD103+ CD8+ TILs in esophageal squamous cell carcinoma (ESCC) were investigated. CD103+ CD8+ TILs were presented in ESCC, which displayed phenotype of tissue-resident memory T cells and exhibited high expression of immune checkpoints (PD-1, TIM-3). CD103+ CD8+ TILs were positively associated with the overall survivals of ESCC patients. This population of cells elicited potent proliferation and cytotoxic cytokine secretion potential. In addition, CD103+ CD8+ TILs were elicited potent anti-tumor immunity after anti-PD-1 blockade and were not affected by chemotherapy. This study emphasized the feature of CD103+ CD8+ TILs in immune response and identified potentially new targets in ESCC patients.

Neoadjuvant chemotherapy versus neoadjuvant chemoradiotherapy for locally advanced oesophageal squamous cell carcinoma: a single-Centre, open-label, randomized, controlled, clinical trial (HCHTOG1903).

BACKGROUND: Neoadjuvant therapy plus oesophagectomy has been accepted as the standard treatment for patients with potentially curable locally advanced oesophageal cancer. No completed randomized controlled trial (RCT) has directly compared neoadjuvant chemotherapy and neoadjuvant chemoradiation in patients with oesophageal squamous cell carcinoma (ESCC). The aim of the current RCT is to investigate the impact of neoadjuvant chemotherapy plus surgery and neoadjuvant chemoradiotherapy plus surgery on overall survival for patients with resectable locally advanced ESCC. METHODS: This open label, single-centre, phase III RCT randomized patients (cT2-T4aN + M0 and cT3-4aN0M0) in a 1:1 fashion to receive either the CROSS regimen (paclitaxel 50 mg/m2; carboplatin (area under the curve = 2), q1w, 5 cycles; and concurrent radiotherapy, 41.4 Gy/23 F, over 5 weeks) or neoadjuvant chemotherapy (paclitaxel 175 mg/m2; and cisplatin 75 mg/m2, q21d, 2 cycles). Assuming a 12% 5-year overall survival difference in favour of the CROSS regimen, 80% power with a two-sided alpha level of 0.05 and a 5% dropout each year for an estimated 3 years enrolment, the power calculation requires 456 patients to be recruited (228 in each group). The primary endpoint is 5-year overall survival, with a minimum 5-year follow-up. The secondary endpoints include 5-year disease-free survival, toxicity, pathological complete response rate, postoperative complications, postoperative mortality and quality of life. A biobank of pre-treatment and resected tumour tissue will be built for translational research in the future. DISCUSSION: This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies. TRIAL REGISTRATION: NCT04138212, date of registration: October 24, 2019.

A sensitive quantification approach for detection of HETE-CP adduct after benzyl chloroformate derivatization using ultra-high-pressure liquid chromatography tandem mass spectrometry.

Sulfur mustard (HD) reacts with human serum albumin (HSA) at Cys34 and produces a long-term biomarker of HD exposure. Here, we present a novel, sensitive, and convenient method for quantification of HD exposure by detection of HD-HSA adducts using pronase digestion, benzyl chloroformate (Cbz-Cl) derivatization, and ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The HSA in HD-exposed plasma in vitro was precipitated with acetone and digested (2 h, 50 °C) with pronase to form the alkylated dipeptide, S-hydroxyethylthioethyl-CysPro (HETE-CP). The HETE-CP adduct was derivatized with Cbz-Cl to generate N-carbobenzoxy HETE-CP (HETE-C(Cbz)P). The derivatized product was analyzed by UHPLC-MS/MS. HD surrogate, 2-chloroethyl ethyl sulfide (2-CEES), was introduced as a non-isotope internal standard (ISTD) instead of traditional d8-HD for quantification. The method was found to be linear between 1.00 and 200 ng/mL HD exposure (R2 > 0.998) with precision of ≤ 9.0% relative standard deviation (RSD) and accuracy ranged between 97.1 and 111%. The limit of detection (LOD) is 0.500 ng/mL (S/N~5), over 15 times lower than that of the previous method (7.95 ng/mL). Time-consuming affinity purification or solid phase extraction (SPE) is not needed in the experiment and the operation takes less than 5 h. This study provides a new strategy and useful tool for retrospective analysis of HD exposure by HETE-CP biomarker detection. Graphical abstract Flow diagram for quantification of sulfur mustard exposure by detection of HETE-CP dipeptide adduct after benzyl chloroformate derivatization using ultra-high-pressure liquid chromatography tandem mass spectrometry.

NONO promotes gallbladder cancer cell proliferation by enhancing oncogenic RNA splicing of DLG1 through interaction with IGF2BP3/RBM14.

Gallbladder cancer (GBC) is a highly malignant and rapidly progressing tumor of the human biliary system, and there is an urgent need to develop new therapeutic targets and modalities. Non-POU domain-containing octamer-binding protein (NONO) is an RNA-binding protein involved in the regulation of transcription, mRNA splicing, and DNA repair. NONO expression is elevated in multiple tumors and can act as an oncogene to promote tumor progression. Here, we found that NONO was highly expressed in GBC and promoted tumor cells growth. The dysregulation of RNA splicing is a molecular feature of almost all tumor types. Accordingly, mRNA-seq and RIP-seq analysis showed that NONO promoted exon6 skipping in DLG1, forming two isomers (DLG1-FL and DLG1-S). Furthermore, lower Percent-Spliced-In (PSI) values of DLG1 were detected in tumor tissue relative to the paraneoplastic tissue, and were associated with poor patient prognosis. Moreover, DLG1-S and DLG1-FL act as tumor promoters and tumor suppressors, respectively, by regulating the YAP1/JUN pathway. N6-methyladenosine (m6A) is the most common and abundant RNA modification involved in alternative splicing processes. We identified an m6A reader, IGF2BP3, which synergizes with NONO to promote exon6 skipping in DLG1 in an m6A-dependent manner. Furthermore, IP/MS results showed that RBM14 was bound to NONO and interfered with NONO-mediated exon6 skipping of DLG1. In addition, IGF2BP3 disrupted the binding of RBM14 to NONO. Overall, our data elucidate the molecular mechanism by which NONO promotes DLG1 exon skipping, providing a basis for new therapeutic targets in GBC treatment.

Inhibition of XPO1 impairs cholangiocarcinoma cell proliferation by triggering p53 intranuclear accumulation.

BACKGROUND: XPO1 mediates the nuclear export of several proteins, mainly tumor suppressors. KPT-330 (Selinexor) is a selective inhibitor of XPO1 that has demonstrated good therapeutic effects in hematologic cancers. METHODS: We used TCGA and GTEx pan-cancer database to evaluate XPO1 mRNA expression in various tumors. Cell proliferation assay and colony formation assay were used to analyze the in vitro antitumor effects of XPO1 inhibitor KPT-330. Western blot was performed to explore the specific mechanisms. RESULTS: We found that XPO1 was highly expressed across a range of cancers and associated with poor prognosis in hepatobiliary and pancreatic tumors. We revealed that the XPO1 inhibitor KPT-330 triggered the nuclear accumulation of the p53 protein and significantly disrupted the proliferation of cholangiocarcinoma cells. Mechanistically, the XPO1 inhibitor, KPT-330, reduced BIRC6 expression by inhibiting the PI3K/AKT pathway to decrease p53 degradation and improve its stability. CONCLUSION: Therefore, XPO1 may be a potential therapeutic target in cholangiocarcinoma, mediated by its effects on KPT-330.

Perioperative Outcomes and Learning Curve of Robot-Assisted McKeown Esophagectomy.

BACKGROUND: This study aimed to evaluate the perioperative outcomes of patients undergoing robot-assisted McKeown esophagectomy (RAME) and the learning curves of surgeons performing RAME at a single center. METHODS: Perioperative outcomes of RAME and video-assisted McKeown esophagectomy (VAME) were compared after eliminating confounding factors by propensity score matching (PSM). The cumulative sum (CUSUM) method was used to evaluate the learning curves of RAME for a single surgical team. RESULTS: In general, a total of 198 patients with esophageal cancer (RAME: 45 patients, VAME: 153 patients) were included in this study, and 43 pairs of patients receiving RAME or VAME were matched using 1:1 PSM analysis. Those in the RAME group had more lymph nodes dissected in the total lymph nodes (median 29.0 vs. 26.0, P = 0.011) and the upper mediastinum (median 8.0 vs. 6.0, P < 0.001), especially the left recurrent laryngeal nerve (RLN) lymph node (median 4.0 vs. 2.0, P = 0.001). According to the trend of the CUSUM plot, the learning curve was divided into two stages at the 20th RAME procedure. After mastering the learning curve, RAME harvested a significantly higher number of upper mediastinal lymph nodes (median 9.0 vs. 6.0, P = 0.001), left RLN lymph nodes (median 5.0 vs. 3.5, P = 0.003), and right RLN lymph nodes (median 4.0 vs. 2.0, P = 0.002). Meanwhile, the incidence of postoperative pneumonia in the proficiency phase was significantly lower than that in the learning phase (4.0% vs. 25.0%, P = 0.04). CONCLUSIONS: RAME improved left RLN lymph node dissection. Surgeons with extensive VAME experience need at least 20 cases to achieve early proficiency in RAME.

A protein standard absolute quantification strategy for enhanced absolute quantification of ricin in complex matrices using in vitro synthesized mutant holoprotein as internal standard by ultra-high-performance liquid chromatography-tandem mass spectrometry.

Ricin is a highly toxic protein toxin that poses a potential bioterrorism threat due to its potency and widespread availability. However, the accurate quantification of ricin through absolute mass spectrometry (MS) using a protein standard absolute quantification (PSAQ) strategy is not widely practiced. This limitation primarily arises from the presence of interchain disulfide bonds, which hinder the production of full-length isotope-labeled ricin as an internal standard (IS) in vitro. In this study, we have developed a novel approach for the absolute quantification of ricin in complex matrices using recombinant single-chain and full-length mutant ricin as the protein IS, instead of isotope-labeled ricin, in conjunction with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The amino acid sequence of the ricin mutant internal standard (RMIS) was designed by introducing site mutations in specific amino acids of trypsin/Glu-C enzymatic digestion marker peptides of ricin. To simplify protein expression, the A-chain and B-chain of RMIS were directly linked to replace the original interchain disulfide bonds. The RMISs were synthesized using an Escherichia coli expression system. An appropriate RMIS was selected as the protein IS based on consistent digestion efficiency, UHPLC-MS/MS behavior, antibody recognition function, lectin activity, and proper depurination activity with intact ricin. The RMIS was utilized to simultaneously quantify A- and B-chain marker peptides of ricin through UHPLC-MS/MS. This method was thoroughly validated using a milk matrix. By employing internal protein standards, this quantitative strategy overcomes the challenges posed by variations in extraction recoveries, matrix effects, and digestion efficiency encountered when working with different matrices. Consequently, calibration curves generated from milk matrix-spiked samples were utilized to accurately and precisely quantify ricin in river water and plasma samples. Moreover, the established method successfully detected intact ricin in samples obtained from the sixth Organization for the Prohibition of Chemical Weapons (OPCW) exercise on biotoxin analysis. This study presents a novel PSAQ strategy that enables the accurate quantification of ricin in complex matrices.

Generic detection of organophosphorus nerve agent adducts to butyrylcholinesterase in plasma using liquid chromatography-tandem mass spectrometry combined with an improved procainamide-gel separation and pepsin digestion method.

Organophosphorus nerve agent (OPNA) adducts to butyrylcholinesterase (BChE) can be applied to confirm exposure in humans. A sensitive method for generic detection of G- and V-series OPNA adducts to BChE in plasma was developed by combining an improved procainamide-gel separation (PGS) and pepsin digestion protocol with ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Residual matrix interferences from prior PGS purification of OPNA-BChE adducts from plasma were found to be a critical cause of significantly reduced UHPLC-MS/MS detection sensitivity. In our developed on-column PGS approach, the matrix interference was successfully removed by adding an appropriate concentration of NaCl to the washing buffer, and it could capture ≥92.5% of the BChE in plasma. The lower pH value and the longer digestion time in all previous pepsin digestion methods were found to be a key accelerated aging factor of several adducts such as tabun (GA)-, cyclohexylsarin (GF)-, and soman (GD)-BChE nonapeptide adducts, making them difficult to detect. The aging event of several OPNA-BChE nonapeptide adducts was so successfully addressed that the formic acid level in enzymatic buffer and digestion time were lowered to 0.05% (pH 2.67) and 0.5 h, respectively, and the post-digestion reaction was immediately terminated. The improved condition parameters were optimal for pepsin digestion of all types of OPNA-BChE adducts into their individual unaged nonapeptide adducts with the highest yields, expanding the applicability of the method. The method had a nearly one-fold decrease in sample preparation time through the reduction of digestion time and removal of ultrafiltration procedure after digestion. The limit of identification (LOI) were determined respectively as 0.13 ng mL-1, 0.28 ng mL-1, 0.50 ng mL-1, 0.41 ng mL-1 and 0.91 ng mL-1 for VX-, sarin (GB)-, GA-, GF-, and GD-exposed human plasma, being low exposure value compared to previously documented approaches. The approach was utilized to fully characterize the adducted (aged and unaged) BChE levels of five OPNAs in a series of their individual exposed concentration (1.00-400 nM) of plasma sample, and successfully detect OPNA exposure from all unknown plasma samples from OPCW's second and third biomedical proficiency tests. The OPNA-BChE adducts, their aged adducts, and unadducted BChE from OPNA-exposed plasma can simultaneously be measured using the method. The study provides a recommended diagnostic tool for generic verification of any OPNA exposure with high confidence by detecting its corresponding BChE adduct.

Initial experience with modified en bloc robot-assisted minimally invasive oesophagectomy for thoracic oesophageal squamous cell carcinoma.

BACKGROUND: The feasibility and safety of en bloc robot-assisted minimally invasive oesophagectomy (RAMIE) need to be verified. METHODS: Forty-seven patients who received conventional RAMIE and 31 who received modified en bloc RAMIE at Henan Cancer Hospital were included in the study cohort. We compared the perioperative outcomes of conventional RAMIE and modified en bloc RAMIE. RESULTS: Compared with the conventional RAMIE group, the en bloc RAMIE group yielded a higher total number of lymph nodes (p = 0.001), especially thoracic lymph nodes (p = 0.025) and left recurrent laryngeal nerve (RLN) lymph nodes (p = 0.005). No notable differences were found in the rate of total complications (p = 0.663) or RLN injury (p = 0.891) between the two groups. The preoperative and postoperative serological indicators were comparable between the two groups. CONCLUSIONS: Modified en bloc RAMIE was safe and feasible for patients with oesophageal squamous cell carcinoma and improved lymph node dissection, especially thoracic and left RLN lymph node dissection.