Физиологические аспекты энтерогепатической циркуляции желчных кислот в контексте определения механизмов возникновения и развития патологий гепатобилиарной системы

Enterohepatic circulation of bile acids is a highly regulated process of secretion of these compounds, intestinal reabsorption and reverse transport to the liver. Violation of this process has significant consequences for the homeostasis of the gastrointestinal tract, liver and the whole organism. This process is tightly controlled by regulatory enzymatic reactions with negative feedback, which leads to the maintenance of a pool and adequate homeostasis of bile acids. The main purpose of this article is to consider the mechanism of enterohepatic circulation of bile acids and evaluate their role both in the formation of pathologies of the hepatobiliary system of various origins, and as a predictor of such processes. We searched for original studies in the scientific databases PubMed, Elsevier Science (Scopus) and Clarivate Analytics (Web of Science) over the past 20 years to identify the features of the above processes, after which a formalized content analysis of the found publications was carried out. Theoretically, every factor that disrupts the enterohepatic circulation leads to pathologies of the hepatobiliary system. However, there are still many unknown aspects when it comes to the regulation of bile acid homeostasis in the enterohepatic circulation. In the last few decades, it is believed that the most important prerequisites for the occurrence of hepatopathy are hypersecretion of bile cholesterol and supersaturation of bile with it. An equally important problem is the change in the pool of bile acids, since its various representatives differ both in chemical activity and in the mechanism of action (from cytotoxicity to cytoprotection).Энтерогепатическая циркуляция жёлчных кислот представляет собой строго регулируемый процесс секреции данных соединений, кишечной реабсорбции и обратного транспорта в печень. Нарушение этого процесса имеет значительные последствия для гомеостаза желудочно-кишечного тракта, печени и всего организма. Данный процесс жёстко контролируется регуляторными ферментативными реакциями с отрицательной обратной связью, что приводит к поддержанию пула и адекватного гомеостаза жёлчных кислот. Основная цель данной статьи – рассмотреть механизм энтерогепатической циркуляции жёлчных кислот и оценить их роль как в формировании патологий гепатобилиарной системы различного генеза, так и в качестве предиктора подобных процессов. Нами был проведён поиск оригинальных исследований в научных базах PubMed, Elsevier Science (Scopus) и Clarivate Analytics (Web of Science) за последние 20 лет для выявления особенностей протекания вышеописанных процессов, после чего был проведён формализованный контент-анализ найденных публикаций. Теоретически каждый фактор, нарушающий энтерогепатическую циркуляцию, приводит к патологиям гепатобилиарной системы. Тем не менее все еще остается много неизвестных аспектов, когда речь идет о регуляции гомеостаза жёлчных кислот в энтерогепатическом кровообращении. В последние несколько десятилетий считается, что наиболее важными предпосылками возникновения гепатопатий являются гиперсекреция жёлчного холестерина и перенасыщение им желчи. Не менее важной проблемой является изменение пула жёлчных кислот, так как разные его представители различаются как по химической активности, так и механизмом действия (от цитотоксичности до цитопротекции)

Лёд и снег озера Стемме (о. Западный Шпицберген) зимой 2019/20 г.

The results of observations and modeling of the formation of the snow-ice cover of Lake Stemme (West Svalbard Island) in winter 2019/20 are presented. The main information was obtained by two radar (GPR) survey, performed on the floating ice of the Lake on March 12 and April 22 of 2020. Authors believe that probably these observations were the first ones on the Lake. The use of the radar made it possible to obtain data on the dynamics of the thickness of the layers of snow and ice cover, the so-called “snow ice” which is formed when the boundary between snow and ice was submerged under water. During the time between records, the thickness of the last “snow ice” increased two to three times, i.e., from units to the first tens of cm, and it spread to the entire deep-water part of the Lake area. In addition, analysis of high-precision positioning of the radar records revealed a significant deflection in the ice surface in the central part of the Lake under the influence of snow load and the decreasing level of the reservoir. The calculations of the thermodynamics of the floating ice cover have shown that its thickening occurs as a result of the processes of congelation and isostatic ice formation, replacing each other at its lower and upper boundaries, respectively. At the same time, the formation of “snow ice” violates the characteristic feature of decreasing of ice thickness with growth of the snow thickness, which significantly influences on the thermal and mass balance of the Lake snow-ice cover. Results of calculations of the ice cover deformation did show that it takes place not only due to the elastic, but also to the viscous properties of ice, and it is concentrated in a narrow coastal zone. The maximum radial stress is reached at a distance of several meters from the shore, where a circular crack parallel to the shoreline is formed. Such a crack is formed at all ice thicknesses at about the same distance from the shore.Представлены и проанализированы результаты комплексных наблюдений снежно-ледяного покрова оз. Стемме (о. Западный Шпицберген) зимой 2019/20 г. Полевые данные дополнены результатами моделирования, описывающими особенности его нарастания и деформации

The effectiveness of absorption heat pumps application for the increase of economic efficiency of CHP operation

The article deals with a comparative analysis of CHP operational efficiency in various working modes before and after the absorption heat pumps installation. The calculation was performed using a mathematical model of the extraction turbine PT- 80/100-130/13. Absorption heat pumps of LLC “OKB Teplosibmash” were used as AHP models for the analysis. The most effective way of absorption lithium-bromide heat pumps application as a part of the turbine PT-80/100-130/13 turned out to be their usage in a heat-producing mode during a non-heating season with a load of hot water supply. For this mode the dependence of the turbine heat efficiency on the heat load of the external consumer at a given throttle flow was analyzed

The effectiveness of absorption heat pumps application for the increase of economic efficiency of CHP operation

The article deals with a comparative analysis of CHP operational efficiency in various working modes before and after the absorption heat pumps installation. The calculation was performed using a mathematical model of the extraction turbine PT- 80/100-130/13. Absorption heat pumps of LLC “OKB Teplosibmash” were used as AHP models for the analysis. The most effective way of absorption lithium-bromide heat pumps application as a part of the turbine PT-80/100-130/13 turned out to be their usage in a heat-producing mode during a non-heating season with a load of hot water supply. For this mode the dependence of the turbine heat efficiency on the heat load of the external consumer at a given throttle flow was analyzed

The analysis of the external factors influence on the efficiency of the absorption heat pumps inclusion in the scheme of a two-stage line installation of a STP

The article deals with a comparative analysis of the efficiency of a two-stage line installation in a heating turbine before and after the inclusion of absorption heat pumps into its scheme with a decrease in the outside air temperature. The research shows the dependence of the efficiency of the line installation on its heat load while using AHP in its scheme, as well as on the heat conversion factor of the absorption heat pumps

A novel preliminary metabolomic panel for IHD diagnostics and pathogenesis

Abstract Cardiovascular disease (CVD) represents one of the main causes of mortality worldwide and nearly a half of it is related to ischemic heart disease (IHD). The article represents a comprehensive study on the diagnostics of IHD through the targeted metabolomic profiling and machine learning techniques. A total of 112 subjects were enrolled in the study, consisting of 76 IHD patients and 36 non-CVD subjects. Metabolomic profiling was conducted, involving the quantitative analysis of 87 endogenous metabolites in plasma. A novel regression method of age-adjustment correction of metabolomics data was developed. We identified 36 significantly changed metabolites which included increased cystathionine and dimethylglycine and the decreased ADMA and arginine. Tryptophan catabolism pathways showed significant alterations with increased levels of serotonin, intermediates of the kynurenine pathway and decreased intermediates of indole pathway. Amino acid profiles indicated elevated branched-chain amino acids and increased amino acid ratios. Short-chain acylcarnitines were reduced, while long-chain acylcarnitines were elevated. Based on these metabolites data, machine learning algorithms: logistic regression, support vector machine, decision trees, random forest, and gradient boosting, were used for IHD diagnostic models. Random forest demonstrated the highest accuracy with an AUC of 0.98. The metabolites Norepinephrine; Xanthurenic acid; Anthranilic acid; Serotonin; C6-DC; C14-OH; C16; C16-OH; GSG; Phenylalanine and Methionine were found to be significant and may serve as a novel preliminary panel for IHD diagnostics. Further studies are needed to confirm these findings