Interpretation of contradictory images by means of systems of linear inequalities

We consider the problem of interpretation of three-dimensional images from their flat projections up to the set of visible faces. For projections of convex polyhedra, we present an interpretation algorithm based on maximal feasible subsystems of a certain infeasible system of linear inequalities modeling the visibility requirement for faces. A number of model examples are given; in particular, the algorithm is applied to the interpretation of the Necker cube. © 2013 Pleiades Publishing, Ltd

ОБОРОТ ТРОМБОЦИТОВ И АТЕРОТРОМБОЗ

Platelets play an important role in initiating atherothrombosis, i.e. the formation of blood clots inside a blood vessel at areas of atherosclerotic vascular injury. The functional (prothrombotic) activity of platelets significantly varies both in healthy individuals and in patients with cardiovascular diseases. The increased platelet production and turnover may be one of the reasons for promoting platelet activity. Stimulating thrombocytopoiesis results in large and reticular (with an increased amount of RNA) "young" platelets in the bloodstream. These platelets contain more adhesive receptors, more secretory granules and have an increased aggregation capacity. The review provides data indicating that large and reticular platelets are not only markers, but also predictors of atherothrombotic events, and primarily of acute coronary syndrome. An increase in such platelet count in patients receiving antiplatelet drugs is associated with a decrease in effectiveness of their antiplatelet action. It is assumed that the appearance of large and reticular platelets in the blood of patients with atherosclerosis and atherothrombosis may be a consequence of an increase in the thrombopoietic activity of megakaryocytes in these pathological conditions.Тромбоциты играют ведущую роль в инициации атеротромбоза – образования внутрисосудистых тромбов в участках атеросклеротическом повреждении сосудов. Функциональная (протромботическая) активность тромбоцитов существенным образом варьирует как у здоровых лиц, так и у пациентов с сердечно-сосудистыми заболеваниями. Одной из причин повышения активности тромбоцитов может быть ускорение их продукции и оборота. При стимуляции тромбоцитопоэза в кровотоке появляются крупные и ретикулярные (с повышенным количеством РНК) «молодые» тромбоциты. Эти тромбоциты содержат больше адгезивных рецепторов, больше секреторных гранул и обладают повышенной способностью к агрегации. В обзоре приводятся данные, указывающие на то, что крупные и ретикулярные тромбоциты являются не только маркерами, но и предикторами атеротромботических событий, и в первую очередь острого коронарного синдрома. Увеличение количества таких тромбоцитов у больных, получающих антитромбоцитарные препараты, ассоциировано со снижением эффективности их антиагрегантного действия. Предполагается, что появление крупных и ретикулярных тромбоцитов в крови больных с атеросклерозом и атеротромбозом может быть следствием повышения тромбопоэтической активности мегакариоцитов при этих патологических состояниях

Finite groups isospectral to simple groups

The spectrum of a finite group is the set of element orders of this group. The main goal of this paper is to survey results concerning recognition of finite simple groups by spectrum, in particular, to list all finite simple groups for which the recognition problem is solved

Diagnostics of thrombocytopenias

Laboratory methods used for the diagnostics of thrombocytopenias are reviewed. Differential diagnosis is usually carried out between immune and hypoproductive forms of thrombocytopenia. Immune thrombocytopenias are caused by appearance in blood of antiplatelet abtibodies and accelerated destruction of platelets sensibilized by those antibodies, and hypoproductive thrombocytopenias - by impaired platelet production in the bone marrow. Main directions of the laboratory diagnostics of thrombocytopenias - analysis of auto - and alloautoantibodies and evaluation of platelet production and turnover in the blood stream. The following methods are used for the investigation of antiplatelet antibodies: 1) measurement of platelet associated immunoglobulins; 2) determination of circulating antibodies reacting with platelets; 3) determination of antibodies using antigen specific methods - by their reactivity with isolated platelet antigens (glycoproteins). Efficacy of platelet production could be assessed by measuring in blood the amount of “young” (reticulated) platelets. One more method for the evaluation of platelet production as well as the rate of platelet turnover - measurement of plasma soluble glycocalicin, glycoprotein Ib fragment shed from the surface of platelets upon their destruction in spleen and liver. In patients with immune thrombocytopenia autoantibodies are evaluated in all cases, the percentage of reticulated platelets is significantly increased and the amount of plasma glycocalicin is within the normal range or increased. In patients with hypoproductive thrombocytopenia autoantibodies are not detected or detected at low level, the percentage of reticulated platelets is within the normal range or slightly increased and the amount of plasma glycocalicin is lowered. Diagnostics of hapten forms of immune thromocytopenias (heparin-induced thrombocytopenia and others) and of alloimmune thrombocytopenias (neonatal alloimmune thrombocytopenia in particular) are considered in the separate sections of this review

АПТАМЕРЫ — НОВЫЕ ФАРМАКОЛОГИЧЕСКИЕ СУБСТАНЦИИ ДЛЯ АНТИКОАГУЛЯНТОВ

A ptamers are a new class of oligonucleotide compounds capable of specific binding to various molecular targets and inhibiting their activity. Aptamers are selected from a library of randomly syn-thesized oligonucleotides (from 20 to 60 nucleotides long) based on their ability to bind to the target molecule. In the future, such primary aptamers can be chemically modified to optimize their structure and increase stability. Aptamers are considered to be chemical (oligonucleotide) analogues of monoclonal antibodies: their specificity is similar to that of antibodies, and they have high affinity to their targets. Aptamers are widely used to create pharmacological medicines. As pharmacological substances, they have a number of benefits over antibodies and other protein molecules. Aptamers are practically non-immunogenic, chemically synthesized without the use of biological producers, and their antidotes can easily be created using complementary sequences. The review highlights reports devoted to the development of new anticoagulant aptamer-based medications. The most detailed studies, both preclinical and clinical (various phases of clinical trials), were performed in relation to the study of aptamers against vWF, factor IX and thrombin.  Аптамеры представляют собой новый класс олигонуклеотидных соединений, способных специфически взаимодействовать с различными молекулярными мишенями и ингибировать их активность. Аптамеры получают путем отбора из библиотеки случайно синтезированных олигонуклеотидов (длина от 20 до 60 нуклеотидов) по их способности к связыванию с молекулой-мишенью. В дальнейшем такие первичные аптамеры могут быть химически модифицированы с целью оптимизации их структуры и повышения стабильности. Аптамеры принято считать химическими (олигонуклеотидными) аналогами моноклональных антител, т. к. они обладают близкими к антителам показателями специфичности и сродства (аффинности) по отношению к своим мишеням. Аптамеры активно используются для создания фармакологических препаратов. Как фармакологические субстанции они обладают рядом преимуществ перед антителами и другими белковыми молекулами. Аптамеры практически неиммуногенны, они синтезируются химическим путем без использования биологических продуцентов, и для них могут быть легко созданы антидоты на основе комплементарных последовательностей. В обзоре рассматриваются работы, направленные на создание новых антикоагулянтных препаратов аптамерной природы. Наиболее подробные исследования, как доклинические, так и клинические (в рамках различных фаз клинических испытаний), были выполнены при изучении аптамеров против фактора Виллебранда, фактора IX и тромбина. 

Geometric estimation of volcanic eruption column height from GOES-R near-limb imagery-Part 2: Case studies

In a companion paper (Horváth et al., 2021), we introduced a new technique to estimate volcanic eruption column height from extremely oblique near-limb geostationary views. The current paper demonstrates and validates the technique in a number of recent eruptions, ranging from ones with weak columnar plumes to subplinian events with massive umbrella clouds and overshooting tops that penetrate the stratosphere. Due to its purely geometric nature, the new method is shown to be unaffected by the limitations of the traditional brightness temperature method, such as height underestimation in subpixel and semitransparent plumes, ambiguous solutions near the tropopause temperature inversion, or the lack of solutions in undercooled plumes. The side view height estimates were in good agreement with plume heights derived from ground-based video and satellite stereo observations, suggesting they can be a useful complement to established techniques

Safety issues of monoclonal antibodies used in rheumatology

Success in practical rheumatology of the latest decade achieved mainly due to monoclonal antibodies (MABs) appearance in routine medical practice. At the same time, the experience of practical application of MABs is limited both by observation period and exposure and their clinical and pharmacological properties do not allow to fully characterizing their safety profile with the data from clinical studies. The use of MABs is associated with the risk of delayed adverse drug reactions (ADRs) — types B (immunoallergic reactions), C (new diseases) and D (delayed teratogenic and oncogenic effects). Determination of risk factors in real medical evidence is especially important. The risk factors of ADRs including serious ADRs were studied based on an analysis of the spontaneous reports database of the Federal Service for Supervision in Healthcare and the data from rheumatologic register of patients receiving MABs — the E.E. Eikhvald Clinic in North-Western State Medical University named after I.I. Mechnikov. It was shown that the factors coming from the patient (gender, age group) do not affect the severity of the risk of occurrence of ADR, including serious ADRs, while the risk factor for monoclonal antibodies can be considered the choice of tocilizumab, which increases the risk of serious ADRs

Применение ингибитора фосфодиэстеразы 4 у пациентов с псориатическим артритом

Psoriatic arthritis (PsA) is a chronic inflammatory disease of the joints, spine, and entheses, which is associated with psoriasis. The pathological process is localized mainly in the tissues of the locomotor system and leads to the development of erosive arthritis, intra-articular osteolysis, and spondyloarthritis. Nonsteroidal anti-inflammatory drugs, glucocorticoids, disease-modifying antirheumatic drugs (DMARDs), biological agents (BAs), and targeted synthetic drugs (or signaling pathway blockers) are used to treat PsA. The latter group of drugs includes apremilast, a phosphodiesterase 4 inhibitor. Recent data of controlled studies suggest that apremilast is effective and safe in treating psoriasis and PsA. Prospects for the use of apremilast in PsA are associated with the possibility of giving the drug to patients because of the inefficacy of DMARDs or BAs. Псориатический артрит (ПсА) – хроническое воспалительное заболевание суставов, позвоночника и энтезисов, ассоциированное с псориазом. Патологический процесс локализуется преимущественно в тканях опорно-двигательного аппарата и приводит к развитию эрозивного артрита, внутрисуставного остеолиза и спондилоартрита. Для лечения ПсА применяют нестероидные противовоспалительные препараты, глюкокортикоиды, базисные противовоспалительные препараты (БПВП), генно-инженерные биологические препараты (ГИБП) и таргетные синтетические препараты (или блокаторы сигнальных путей). К последней группе препаратов относится апремиласт, ингибитор фосфодиэстеразы 4. Полученные к настоящему времени данные контролируемых исследований свидетельствуют о том, что апремиласт эффективен и безопасен при лечении псориаза и ПсА. Перспективы применения апремиласта при ПсА связаны с возможностью использовать препарат у пациентов с неэффективностью БПВП или ГИБП.

Use of Thrombodynamics for revealing the participation of platelet, erythrocyte, endothelial, and monocyte microparticles in coagulation activation and propagation

Background and objective: For many pathological states, microparticles are supposed to be one of the causes of hyper-coagulation. Although there are some indirect data about microparticles participation in coagulation activation and propagation, the integral hemostasis test Thrombodynamics allows to measure micropaticles participation in these two coagulation phases directly. Demonstrates microparticles participation in coagulation activation by influence on the appearance of coagulation centres in the plasma volume and the rate of clot growth from the surface with immobilized tissue factor.Methods: Microparticles were obtained from platelets and erythrocytes by stimulation with thrombin receptor-activating peptide (SFLLRN) and calcium ionophore (A23187), respectively, from monocytes, endothelial HUVEC culture and monocytic THP cell culture by stimulation with lipopolysaccharides. Microparticles were counted by flow cytometry and titrated in microparticle-depleted normal plasma in the Thrombodynamics test.Results: Monocyte microparticles induced the appearance of clotting centres through the TF pathway at concentrations approximately 100-fold lower than platelet and erythrocyte microparticles, which activated plasma by the contact pathway. For endothelial microparticles, both activation pathways were essential, and their activity was intermediate. Monocyte microparticles induced plasma clotting by the appearance of hundreds of clots with an extremely slow growth rate, while erythrocyte microparticles induced the appearance of a few clots with a growth rate similar to that from surface covered with high-density tissue factor. Patterns of clotting induced by platelet and endothelial microparticles were intermediate. Platelet, erythrocyte and endothelial microparticles impacts on the rate of clot growth from the surface with tissue factor did not differ significantly within the 0-200-10(3)/ulrange of microparticles concentrations. However, at concentrations greater than 500.10(3)/mu l, erythrocyte microparticles increased the stationary clot growth rate to significantly higher levels than do platelet microparticles or artificial phospholipid vesicles consisting of phosphatidylcholine and phosphatidylserine.Conclusion: Microparticles of different origins demonstrated qualitatively different characteristics related to coagulation activation and propagation.</div