СРАВНЕНИЕ ТОЧНОСТИ МЕТОДА АБСОЛЮТНОЙ ГРАДУИРОВКИ И МОДИФИЦИРОВАННОГО МЕТОДА ПОСЛЕДОВАТЕЛЬНЫХ СТАНДАРТНЫХ ДОБАВОК НА ПРИМЕРЕ ОПРЕДЕЛЕНИЯ 3-(2,2,2-ТРИ¬МЕТИЛ¬ГИДРАЗИНИЙ)¬ПРОПИОНОВОЙ КИСЛОТЫ В МОЧЕ В УСЛОВИЯХ НЕЛИНЕЙНОСТИ ДЕТЕКТИРОВАНИЯ (ЭЛ

Contemporary determining of pharmaceuticals in biological liquids for the pur­poses of phar­maco­kine­tic studies and therapeutic drug monitoring implies the use of high-per­formance liquid chromatography coupled with mass spectrometry (LC-MS) with electrospray as a method of ionization. However, this techni­que is cha­rac­terized by a rather narrow linear detection range. It causes the restric­tions in quan­titation of analytes by method of absolute calibration.On the example of the determination of 3-(2,2,2-trimethylhydrazinium) propio­nate (THP) in urine it is shown that the method of successive standard additi­ons provides more precise results comparing with those obtained with non-linear absolu­te calib­ration at the same levels of analyte concentrations. Its principal fea­ture is the need to extrapolate the results to an infinite value of ad­dition.Keywords: 3-(2,2,2-trimethylhydrazinium) propionate, LC-MS, detection non­­­linearity, successive standard addition, non-linear absolute calibration(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.008Тatiana Е. Morozova1, Georgy V. Karakashev1, Pavel N. Sorokoumov1,Elena I. Savelieva1, Igor G. Zenkevich2 1Research Institute of Hygiene, Occupational Pathology and Human Ecology, Russian Federation, Leningrad Region., Vsevolozhsk district, town Kuzmolovsky, Art. Kapitolovo2St. Petersburg State University, Russian Federation, Saint-Petersburg На примере ВЭЖХ-МС определения 3-(2,2,2-триметилгидразиний)про­пионовой кис­лоты (THP) в моче (способ ионизации электроспрей) показано, что применение модифицированного метода последовательных стан­дарт­ных до­бавок, включающего экстраполяцию результатов на бесконечно большую ве­личину добавки, позволяет получать результаты, характеризующиеся большей точнос­тью, чем при использовании нелинейной абсолютной градуиров­ки.Ключевые слова: 3-(2,2,2-триметилгидразиний)пропионовая кислота, ВЭЖХ-МС ана­лиз, нелинейность детектирования, метод последовательных стандартных доба­вок, нелинейная абсолютная градуировкаDOI: http://dx.doi.org/10.15826/analitika.2013.17.2.00

Antarctic polar vortex dynamics in 2019 and 2020 under the influence of the subtropical stratosphere

The trend of strengthening of the Antarctic polar vortex in late spring and early summer (November–December) has been observed in recent decades. A good example of this trend is the dynamics of the Antarctic polar vortex in 2020 when it existed until the last week of December. In 2019, conversely, on the contrary, an unusually early breakup of the polar vortex occurred, a minor sudden stratospheric warming was recorded. Strengthening (or weakening) of the Antarctic polar vortex occurs as a result of an increase (or decrease) in the stratospheric meridional temperature gradient under conditions of growth (or decline) in the temperature of the lower subtropical stratosphere. We considered the temperature variations in the lower subtropical stratosphere in the spring of 2019 and 2020 and the corresponding response of the Antarctic polar vortex. The dynamics of the Antarctic polar vortex in September–October 2019 and November 2020 was largely synchronized with the temperature changes in the lower subtropical stratosphere relative to climatological means. Using correlation analysis, we show that the Antarctic polar vortex dynamics in December is largely due to the temperature changes in the lower subtropical stratosphere that occurred in the second half of November, which manifested itself in 2020.The trend of strengthening of the Antarctic polar vortex in late spring and early summer (November–December) has been observed in recent decades. A good example of this trend is the dynamics of the Antarctic polar vortex in 2020 when it existed until the last week of December. In 2019, conversely, on the contrary, an unusually early breakup of the polar vortex occurred, a minor sudden stratospheric warming was recorded. Strengthening (or weakening) of the Antarctic polar vortex occurs as a result of an increase (or decrease) in the stratospheric meridional temperature gradient under conditions of growth (or decline) in the temperature of the lower subtropical stratosphere. We considered the temperature variations in the lower subtropical stratosphere in the spring of 2019 and 2020 and the corresponding response of the Antarctic polar vortex. The dynamics of the Antarctic polar vortex in September–October 2019 and November 2020 was largely synchronized with the temperature changes in the lower subtropical stratosphere relative to climatological means. Using correlation analysis, we show that the Antarctic polar vortex dynamics in December is largely due to the temperature changes in the lower subtropical stratosphere that occurred in the second half of November, which manifested itself in 2020

HL-1 cells express an inwardly rectifying K+ current activated via muscarinic receptors comparable to that in mouse atrial myocytes

An inwardly rectifying K^+ current is present in atrial cardiac myocytes that is activated by acetylcholine (I_{KACh}). Physiologically, activation of the current in the SA node is important in slowing the heart rate with increased parasympathetic tone. It is a paradigm for the direct regulation of signaling effectors by the Gβγ G-protein subunit. Many questions have been addressed in heterologous expression systems with less focus on the behaviour in native myocytes partly because of the technical difficulties in undertaking comparable studies in native cells. In this study, we characterise a potassium current in the atrial-derived cell line HL-1. Using an electrophysiological approach, we compare the characteristics of the potassium current with those in native atrial cells and in a HEK cell line expressing the cloned Kir3.1/3.4 channel. The potassium current recorded in HL-1 is inwardly rectifying and activated by the muscarinic agonist carbachol. Carbachol-activated currents were inhibited by pertussis toxin and tertiapin-Q. The basal current was time-dependently increased when GTP was substituted in the patch-clamp pipette by the non-hydrolysable analogue GTPγS. We compared the kinetics of current modulation in HL-1 with those of freshly isolated atrial mouse cardiomyocytes. The current activation and deactivation kinetics in HL-1 cells are comparable to those measured in atrial cardiomyocytes. Using immunofluorescence, we found GIRK4 at the membrane in HL-1 cells. Real-time RT-PCR confirms the presence of mRNA for the main G-protein subunits, as well as for M2 muscarinic and A1 adenosine receptors. The data suggest HL-1 cells are a good model to study IKAch

Классификация внутричерепных опухолей на основе оптико-спектрального анализа

The motivation for the present study was the need to develop methods of urgent intraoperative biopsy during surgery for removal of intracranial tumors. Based on the experience of previous joint work of GPI RAS and N.N. Burdenko National Medical Research Center of Neurosurgery to introduce fluorescence spectroscopy methods into clinical practice, an approach combining  various optical-spectral techniques, such as autofluorescence spectroscopy, fluorescence of 5-ALA induced protoporphyrin IX, diffuse reflection of broadband light, which can be used to determine hemoglobin concentration in tissues and their optical density, Raman spectroscopy, which is a spectroscopic method that allows detection of various molecules in tissues by vibrations of individual characteristic molecular bonds. Such a variety of optical and spectral characteristics makes it difficult for the surgeon to analyze them directly during surgery, as it is usually realized in the case of fluorescence methods – tumor tissue can be distinguished from normal with a certain degree of certainty by fluorescence intensity exceeding  a threshold value. In case the number of parameters exceeds a couple of dozens, it is necessary to use machine learning algorithms  to build a intraoperative decision support system for the surgeon. This paper presents research in this direction. Our earlier statistical analysis of the optical-spectral features allowed identifying  statistically significant spectral ranges for analysis of diagnostically  important tissue components. Studies of dimensionality reduction techniques of the optical-spectral feature vector and methods of clustering of the studied samples also allowed us to approach the implementation  of the automatic classification method. Importantly, the classification task can be used in two applications  – to differentiate between different tumors and to differentiate between different parts of the same (center, perifocal zone, normal) tumor. This paper presents the results of our research in the first direction. We investigated the combination of several methods and showed the possibility of differentiating glial and meningeal tumors based on the proposed optical-spectral analysis method.Мотивацией проведения настоящего исследования послужила необходимость развития методов срочной интраоперационной биопсии при проведении операций по поводу удаления внутричерепных опухолей. На основании опыта предыдущей совместной работы ИОФ РАН и НМИЦ нейрохирургии  им. Н.Н. Бурденко по внедрению в клиническую практику методов флуоресцентной спектроскопии был разработан подход, комбинирующий различные оптико-спектральные  методики, такие как спектроскопия  аутофлуоресценции, флуоресценции  5-АЛК индуцированного  протопорфирина  IX, диффузного  отражения  широкополосного излучения,  по которому можно определять концентрацию гемоглобина в тканях и их оптическую  плотность,  спектроскопия  комбинационного  рассеяния, являющаяся методом молекулярной спектроскопии, позволяющим детектировать различные молекулы в тканях за счета колебаний отдельных характерных связей в молекулах. Такое разнообразие оптико-спектральных характеристик  затрудняет их непосредственный анализ хирургом во время операции, как это обычно реализуется в случае флуоресцентных методов – по превышению некоторого порога интенсивности флуоресценции с определенной степенью достоверности можно судить о том, находится ли в зоне исследования нормальная или опухолевая ткань. В случае, если число параметров превышает пару десятков, необходимо использование алгоритмов машинного обучения для построения  системы поддержки принятия  решений хирурга  во время операции. Настоящая работа представляет исследования в этом направлении. Проведенный нами ранее статистический  анализ данных оптико-спектральных характеристик  позволил выделить статистически  значимые спектральные диапазоны для анализа, репрезентирующие  диагностически  важные компоненты тканей. Исследования методов понижения размерности вектора оптико-спектральных признаков  и методов кластеризации исследуемых образцов также позволили приблизиться к реализации метода автоматической классификации. Важно отметить, что задача классификации может быть использована в двух приложениях – для дифференциации различных опухолей и для дифференциации различных частей одной (центр, перифокальная зона, норма) опухоли. В настоящей работе представлены результаты наших исследований в первом направлении. Мы исследовали сочетание нескольких методов и показали возможность дифференциации глиальных и менингеальных опухолей на основании предложенного метода оптико-спектрального анализа

Валидация методики количественного определения наркотических и психотропных веществ в моче методом СВЭЖХ-МС/МС

Objectives. To validate a new method for the quantitative determination of 31 potent and narcotic substances and their metabolites in urine that meets the requirements of ISO/IEC 17025 using a fast and highly sensitive method of chromato-mass spectrometry with a view to introducing such a method into the routine practice of the National Anti-Doping Laboratory of the Lomonosov Moscow State University (NADL MSU).Methods. Urine samples soldered with standard solutions were analyzed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS).Results. Diagnostic precursor/ion-product pairs and collision energies were established to allow unambiguous identification of the analyzed substances. During sample preparation, hydrolysis conditions were optimized. Selectivity, linearity, limits of qualitative determination, limit of quantitative determination (established under the contract with the customer firm), matrix effect, and measurement uncertainty were defined. Systematized data grouped by classes of analytes are given in the final table.Conclusions. The important advantages of the presented technique are the absence of complex and lengthy sample preparation, as well as the short time of the analysis method (about 10 min), which can significantly reduce duration along with labor and analysis costs. The addition of new analytes will ensure the versatility of the technique, as well as expanding its scope. Цели. Валидировать и ввести в рутинную практику НАДЛ МГУ новую, отвечающую требованиям ISO/IEC 17025, методику количественного определения 31 сильнодействующих и наркотических вещества и их метаболитов в моче с использованием быстрого и высокочувствительного метода хромато-масс-спектрометрии.Методы. Анализ спайкованных с растворами стандартов образцов мочи проводили методом сверхэффективной жидкостной хроматографии–тандемной масс-спектрометрии (СВЭЖХ-МС/МС).Результаты. В работе установлены диагностические пары прекурсор/ион-продукт и найдены энергии соударения, позволяющие однозначно идентифицировать анализируемые вещества; оптимизированы условия гидролиза при проведении пробоподготовки; определены селективность, линейность, предел качественного определения, предел количественного определения (установлен в рамках договора с фирмой-заказчиком), эффект матрицы и неопределенность измерения. Систематизированные данные приведены в итоговой таблице и сгруппированы по классам определяемых веществ.Выводы. Представленная методика обладает важными преимуществами – отсутствием сложной и продолжительной пробоподготовки, а также коротким временем метода анализа – около 10 мин, что позволяет существенно снизить трудозатраты, продолжительность и себестоимость анализа. Дополнение новыми определяемыми веществами обеспечит ее универсальность и позволит расширить область применения

EHRA expert consensus document on the management of arrhythmias in frailty syndrome, endorsed by the Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Latin America Heart Rhythm Society (LAHRS), and Cardiac Arrhythmia Society of Southern Africa (CASSA)

There is an increasing proportion of the general population surviving to old age with significant chronic disease, multimorbidity, and disability. The prevalence of pre-frail state and frailty syndrome increases exponentially with advancing age and is associated with greater morbidity, disability, hospitalization, institutionalization, mortality, and health care resource use. Frailty represents a global problem, making early identification, evaluation, and treatment to prevent the cascade of events leading from functional decline to disability and death, one of the challenges of geriatric and general medicine. Cardiac arrhythmias are common in advancing age, chronic illness, and frailty and include a broad spectrum of rhythm and conduction abnormalities. However, no systematic studies or recommendations on the management of arrhythmias are available specifically for the elderly and frail population, and the uptake of many effective antiarrhythmic therapies in these patients remains the slowest. This European Heart Rhythm Association (EHRA) consensus document focuses on the biology of frailty, common comorbidities, and methods of assessing frailty, in respect to a specific issue of arrhythmias and conduction disease, provide evidence base advice on the management of arrhythmias in patients with frailty syndrome, and identifies knowledge gaps and directions for future research

UK–Russia Researcher Links Workshop: extracellular vesicles – mechanisms of biogenesis and roles in disease pathogenesis, M.V. Lomonosov Moscow State University, Moscow, Russia, 1–5 March 2015

The UK–Russia extracellular vesicles (EVs) workshop was held at the Medical Center of the M.V. Lomonosov Moscow State University, Moscow, Russia, with 56 attendees from UK and Russian universities and research institutes. The program consisted of 6 research sessions and was focused on studies of EVs isolated from in vitro model systems or biological fluids, including blood and urine. The multidisciplinary program included presentations on mechanisms of EV biogenesis, the role of EVs in disease pathogenesis, the diagnostic value of EVs, including their quantitation and cargo load, as well as the clinical use of EVs in regenerative medicine. Methodological challenges imposed by the nanoscale size of EVs as well as targeted delivery approaches for therapeutics were considered in a separate session on technologies. The main aim of the workshop was to overview challenges confronting EV researchers and to facilitate knowledge exchange between researchers with different backgrounds and skills. Given the lack of definitive EV nomenclature, specific terms (exosomes or microvesicles) were only applied in the meeting report to studies that carried out full EV characterization, including differential ultracentrifugation isolation approaches, comprehensive protein marker characterization, and single vesicle analysis (electron microscopy and nanoparticle analysis), to ascertain EV size and morphology following the International Society for Extracellular Vesicles standardization recommendations (1,2). In studies where characterization was not conclusive, the term EV is used

Gene expression analysis indicates CB1 receptor upregulation in the hippocampus and neurotoxic effects in the frontal cortex 3 weeks after single-dose MDMA administration in Dark Agouti rats.

BACKGROUND: 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is a widely used recreational drug known to impair cognitive functions on the long-run. Both hippocampal and frontal cortical regions have well established roles in behavior, memory formation and other cognitive tasks and damage of these regions is associated with altered behavior and cognitive functions, impairments frequently described in heavy MDMA users. The aim of this study was to examine the hippocampus, frontal cortex and dorsal raphe of Dark Agouti rats with gene expression arrays (Illumina RatRef bead arrays) looking for possible mechanisms and new candidates contributing to the effects of a single dose of MDMA (15 mg/kg) 3 weeks earlier. RESULTS: The number of differentially expressed genes in the hippocampus, frontal cortex and the dorsal raphe were 481, 155, and 15, respectively. Gene set enrichment analysis of the microarray data revealed reduced expression of 'memory' and 'cognition', 'dendrite development' and 'regulation of synaptic plasticity' gene sets in the hippocampus, parallel to the upregulation of the CB1 cannabinoid- and Epha4, Epha5, Epha6 ephrin receptors. Downregulated gene sets in the frontal cortex were related to protein synthesis, chromatin organization, transmembrane transport processes, while 'dendrite development', 'regulation of synaptic plasticity' and 'positive regulation of synapse assembly' gene sets were upregulated. Changes in the dorsal raphe region were mild and in most cases not significant. CONCLUSION: The present data raise the possibility of new synapse formation/synaptic reorganization in the frontal cortex three weeks after a single neurotoxic dose of MDMA. In contrast, a prolonged depression of new neurite formation in the hippocampus is suggested by the data, which underlines the particular vulnerability of this brain region after the drug treatment. Finally, our results also suggest the substantial contribution of CB1 receptor and endocannabinoid mediated pathways in the hippocampal impairments. Taken together the present study provides evidence for the participation of new molecular candidates in the long-term effects of MDMA