Confirmation of brevetoxin metabolism in cockle, Austrovenus stutchburyi, and greenshell mussel, Perna canaliculus, associated with New Zealand neurotoxic shellfish poisoning, by controlled exposure to Karenia brevis culture.

We examined metabolism of PbTxs in New Zealand cockle, Austrovenus (A.) stutchburyi, and greenshell mussel, Perna (P.) canaliculus, by means of liquid chromatography coupled with tandem mass spectrometry. PbTx-2, PbTx-3 and BTX-B5 were detected in Karenia (K.) brevis culture medium in the ratio of ca. 50:2:5. The amounts of PbTx-3 and BTX-B5 were greatly increased in both seawater and shellfish exposed to K. brevis cultures or supernatant prepared by disruption of K. brevis under appropriate condition, while those of PbTx-2 were decreased. Some PbTx-2 was present in P. canaliculus, but not in A. stutchburyi. Low levels of BTX-B1 were detected in A. stutchburyi, but not P. canaliculus. Levels of PbTx-3 and BTX-B5 were highest immediately after exposure and then declined rapidly in both shellfish. BTX-B1 increased in concentration after exposure, and was then gradually eliminated from A. stutchburyi. Three successive exposures of A. stutchburyi to K. brevis cultures resulted in similar initial levels of PbTx-3 and BTX-B5, while BTX-B1 accumulated after each dose. In P. canaliculus, initial levels of PbTx-3 were similar, while PbTx-2 and BTX-B5 accumulated after each dose. PbTx-3 and BTX-B5 are proposed to be suitable markers for monitoring shellfish toxicity after a red tide event.     

宫颈癌细胞中与UTF1相互作用的蛋白分析

【摘要】目的 探讨宫颈癌细胞中与转录辅激活因子（UTF1）相互作用的蛋白。方法 构建稳定表达FLAG HA 双标签标记的UTF1蛋白的SiHa 细胞株,利用FLAG HA 串联亲和纯化( TAP) 双标签纯化实验,对目的条带进行质谱分析。结果 成功构建稳定表达FLAG HA 双标签标记的UTF1 细胞株。通过质谱分析得到UTF1相互作用的蛋白数据,结果显示UTF1 捕获蛋白参与DNA修复、代谢、核糖体、细胞连接、细胞因子相互作用、吞噬等多种生物学过程,以及Jak STAT、MAPK、mTOR、VEGF、 wnt 等多条信号通路,并与系统性红斑狼疮、帕金森症、阿尔兹海默症、自身免疫性疾病等的发病相关。结论 UTF1 捕获蛋白参与细胞多种生理及病理过程,为进一步了解UTF1在肿瘤发病机制中的作用提供了新的线索。     

Ambient mass spectrometry for rapid diagnosis of psychoactive drugs overdose in an unstable patient

A 25-year-old man suffered from consciousness change was sent to our emergency department by friends who reported that they were not sure what had happened to him. Physical examination revealed bilateral pupils dilatation, lethargy, slurred speech, and ataxia. Computer-aided tomographic scan of the brain revealed no definite evidence of intracranial lesions. Routine laboratory tests revealed total physiological turmoil. Despite immediate commencement of aggressive treatment, the patient's condition deteriorated long before the traditional drug screen provided an answer for the identities of the multiple drugs overdose. It ended up with the need for cardiopulmonary resuscitation, but in vain. At the end of the tragic event, under the suggestion of a colleague, a portion of the patient's urine specimen was sent to our university esoteric laboratory for rapid analysis by means of a newly-developed thermal desorption-electrospray ionization-mass spectrometry. Ketamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyamphetamine were identified in the urine sample within 30 s. Conventional toxicological testing techniques like gas chromatography–mass spectrometry or liquid chromatography-mass spectrometry are currently used for identifying abused drugs. One concern is their time-consuming sample pretreatment which leads to relatively low efficiency in terms of turnaround time for revealing the identity of the consumed drugs particularly when the patients are severely overdosed. We learned a lesson from this case that a more efficient toxicological identification technique is essential to expedite the process of emergency care when the patients are so heavily overdosed that they are under critical life-threatening conditions.     

Application of LC/MS to determine specific activity variation in a series of sulfonamide tracers from the [35S]methane sulfonate reagent

The specific activities for a series of S‐35 tracers were found to vary from the decay‐corrected specific activity of the labeled reagent. If not known before the stock solution preparation and binding assay, this variation would have resulted in performing the assay at approximately two to three times over the targeted concentration, thereby leading to considerable error in the calculated binding and related conclusions. Copyright © 2012 John Wiley & Sons, Ltd.     

Identification of pathogenic microorganisms directly from positive blood vials by matrix‐assisted laser desorption/ionization time of flight mass spectrometry

Matrix‐assisted laser desorption/ionization time of flight mass spectrometry (MALDI‐TOF MS) is a promising and fast method for identifying fungi and bacteria directly from positive blood cultures. Various pre‐treatment methods for MALDI‐TOF MS identification have been reported for this purpose. In‐house results for identification of bacterial colonies by MALDI‐TOF MS using a cut‐off score of 1.5 did not reduce the diagnostic accuracy compared with the recommended cut‐off score of 1.8. A 3‐month consecutive study of positive blood cultures was carried out in our laboratory to evaluate whether the Sepsityper? Kit (Bruker Daltonics) with Biotyper 2.0 software could be used as a fast diagnostic tool for bacteria and fungi and whether a 1.5 cut‐off score could improve species identification compared with the recommended score of 1.8. Two hundred and fifty‐six positive blood vials from 210 patients and 19 blood vials spiked with fungi were examined. Using the cut‐off score of 1.8, 81% Gram‐negative bacteria were identified to the species level compared to 84% using a cut‐off score of 1.5. For Gram‐positive bacteria 44% were identified to the species level with a cut‐off of 1.8 compared to 55% with the value of 1.5. The overall identification rate was 63% (cut‐off 1.5) and 54% (cut‐off 1.8). Seventy‐seven per cent of fungal species were identified with both log scores. MALDI‐TOF MS was in this study found to be a powerful tool in fast diagnosis of Gram‐negative bacteria and fungi and to a lesser degree of Gram positives. Using 1.5 as cut‐off score increased the diagnosis for both Gram‐positives and ‐negatives bacteria.     

Advances in cocaine signature methodology: Alkaloid and isotope profiles of coca grown in Puno,Peru

Drug Enforcement Administration's (DEA) Cocaine Signature Program previously identified 19 coca-growing regions within South America and developed methodology to geo-source cocaine using a combination of trace cocaine alkaloids, stable isotopes, and multivariate statistics. Twenty-nine coca leaf samples collected in 2016 and 2019 from a previously unanalyzed coca-growing region located in Puno, Peru, were analyzed with this methodology. Trace cocaine alkaloids and stable isotopes were compared with other Peruvian regions. Minor differences were observed in the extracted cocaine alkaloid profiles when compared with samples collected from the Ucayali-Huallaga Valley and Cusco-Apurimac regions while the stable isotopes of δ²H (−177.1‰) and δ¹⁸O (23.8‰) were enriched. Puno's alkaloid and stable isotope results are presented in this publication to assist forensic laboratories and enhance their cocaine geo-sourcing capabilities.     

质谱在蛋白质生物标志物发现中的应用策略

生物标志物是可被客观测量并能用于评价正常生物过程、病理过程及治疗反应的指标。生物标志物的发现是对其研究的第一步，其实质就是筛选出在不同的生物学状态或进程中的差异化物质。在这一阶段中，分析策略所考虑的重点是高通量化和定性(和/或半定量)性能。目前，生物标志物研究的热点已转移至蛋白质层面上。在蛋白质生物标志物的发现中，质谱以不同的策略和方式得到了广泛的应用，并仍在不断进步中。本文对蛋白质生物标志物的发现过程中常用的及新型的质谱应用策略进行了归纳阐述。     

Identification of biomarkers for essential hypertension based on metabolomics

AimEssential hypertension (EH) is one of the most important public health problems worldwide. However, the pathogenesis of EH is unclear and early diagnostic methods are lacking. Metabolomics demonstrates great potential for biomarker discovery and the mechanistic exploration of metabolic diseases.Data synthesisThis review included human and animal metabolomics studies related to EH in the PubMed and Web of Science databases between February 1996 and May 2020. The study designs, EH standards, and reported metabolic biomarkers were systematically examined and compared. The pathway analysis was conducted through the online software MetaboAnalyst 4.0.Twenty-two human studies and fifteen animal studies were included in this systematic review. There were many frequently reported biomarkers with consistent trends (e.g., pyruvate, lactic acid, valine, and tryptophan) in human and animal studies, and thus had potential as biomarkers of EH. In addition, several shared metabolic pathways, including alanine, aspartate, and glutamate metabolism, aminoacyl-tRNA biosynthesis, and arginine biosynthesis, were identified in human and animal metabolomics studies. These biomarkers and pathways, closely related to insulin resistance, the inflammatory state, and impaired nitric oxide production, were demonstrated to contribute to EH development.ConclusionsThis study summarized valuable metabolic biomarkers and pathways that could offer opportunities for the early diagnosis or prediction of EH and the discovery of the metabolic mechanisms of EH.     

Counting primary loops in polymer gels

Much of our fundamental knowledge related to polymer networks is built on an assumption of ideal end-linked network structure. Real networks invariably possess topological imperfections that negatively affect mechanical properties; modifications of classical network theories have been developed to account for these defects. Despite decades of effort, there are no known experimental protocols for precise quantification of even the simplest topological network imperfections: primary loops. Here we present a simple conceptual framework that enables primary loop quantification in polymeric materials. We apply this framework to measure the fraction of primary loop junctions in trifunctional PEG-based hydrogels. We anticipate that the concepts described here will open new avenues of theoretical and experimental research related to polymer network structure.