Последовательность действий при визуализации кровоизлияний/гематом мягких тканей у пожилых больных, инфицированных SARS-CoV-2

Aim. To determine ultrasound, computed tomography and angiographic image characteristics for soft tissue hemorrhages/hematomas, the sequence of using imaging methods in patients infected with SARS-CoV-2, to study the morphology of changes in soft tissues, to determine the essence of the concept and to develop treatment tactics for this complication of COVID-19.Material and methods. During 4 months of treatment of elderly patients (+60) infected with SARS-CoV-2, 40 patients were identified with soft tissue hemorrhages/hematomas, of which 26 (65%) patients with large hematomas (>10 cm in size and > 1000 ml in volume). The analysis of clinical and laboratory parameters, methods of instrumental diagnostics (ultrasound – 26 patients, CT – 10 patients, angiography – 9 patients, punctures – 6 patients) was carried out; autopsy material was studied in 11 cases.Results. Image characteristics of hemorrhages/hematomas of soft tissue density were obtained using modern instrumental methods, and the sequence of application of visualization methods was determined. A tactic for managing a patient with stopped and ongoing bleeding has been developed. The morphological substrate of hemorrhagic complications in a new viral infection was studied. All patients were treated with conservative and minimally invasive procedures (embolization, puncture with pressure bandage). 15 patients (57.7%) recovered, 11 patients (42.3%) died from the progression of COVID-19 complications.Conclusion. Comprehensive clinical and laboratory sequential instrumental diagnosis of soft tissue hemorrhages in COVID-19. Treatment should be conservative and significantly invasive. The use of the term “soft tissue hematoma” in SARS-CoV-2 infected patients is not a natural quality of the normal pathological process and should not be observed from our point of view.Цель исследования: определить визуальные ультразвуковые, компьютерно-томографические и ангиографические критерии мягкотканных кровоизлияний/гематом, последовательность использования методов визуализации у больных, инфицированных SARS-CoV-2, изучить морфологию изменений в мягких тканях, определить суть понятия и выработать лечебную тактику при таком осложнении COVID-19.Материал и методы. За 4 мес лечения пожилых больных (+60), инфицированных SARS-CoV-2, выявлено 40 пациентов с мягкотканными кровоизлияниями/гематомами, из них 26 (65%) пациентов с большими гематомами (размер >10 см и объем> 1000 мл). Проведен анализ клинико-лабораторных показателей, методов инструментальной диагностики (УЗИ – 26 пациентов, КТ – 10 пациентов, ангиография – 9 больных, пункции – 6 пациентов), в 11 случаях изучен материал аутопсии.Результаты. Современными инструментальными методами получена визуальная характеристика крово излияний/гематом мягкотканной плотности, определена последовательность применения методов визуализации. Разработана тактика ведения пациента при остановившемся и продолжающемся кровотечении. Изучен морфологический субстрат геморрагического осложнения при новой вирусной инфекции. Все больные пролечены консервативными и минимально инвазивными процедурами (эмболизация, пункция с давящей повязкой). Выздоровели 15 (57,7%) пациентов, умерли от прогрессирования осложнений COVID-19 11 (42,3%) больных.Заключение. Комплексная клинико-лабораторная последовательная инструментальная диагностика мягкотканных кровоизлияний при COVID-19-инфекции позволяет своевременно установить топический диагноз, оценить тяжесть кровопотери, ее остановку или продолжение кровотечения. Лечение должно носить консервативный и минимально инвазивный характер. Использование термина “гематома” мягких тканей у инфицированных SARS-CoV-2 больных не отражает суть происходящего патологического процесса и, с нашей точки зрения, не должно использоваться

What Can Be Learned from the Polymerization of a Pyridine‐Based Two‐Component System

International audienceStable poly (4-vinyl pyridine)/pyridine gels prepared by dissolving solid polymer in pyridine (the equimolar ratio of the pyridine moieties to the pyridine solvent molecules) exhibit sensor properties rapidly and reversibly increasing their conductivity upon irradiation by light in the UV-Vis and NIR ranges. Both ionic and electronic mechanisms of conductivity were detected. The gels behave as polyelectrolytes involving the positively charged pyridine moieties and negatively charged saturated chains held together by a network of hydrogen bonds between the charged and neutral species. This interpretation is corroborated by the cryo-TEM images of the gel samples resembling chains of beads and the analysis of FT-IR and 1H-NMR spectra. Photoinduced proton transfer can thus be responsible for the observed ionic conductivity of the gels. Exposing gels to the ambient light can bring about ring opening of the pyridine moieties and of the free pyridine molecules with subsequent polycondensation of the initially formed 5-amino-2,4-pentadienal. The oligomers of the latter, aza-analogs of polyacetylene, can serve as molecular wires providing the electronic component of electrical conductivity. These oligomers can also contribute to the ionic conductivity and further stabilize the gels by cross-linking of the separate polymer chains

Functional restoration of the Ca2 -myristoyl switch in a recoverin mutant

Recoverin is a neuronal calcium sensor protein that plays a crucial role in vertebrate phototransduction. It undergoes a Ca2+-myristoyl switch when Ca2+ binds to its two functional EF-hand motifs (EF-hands 2 and 3), each present in one of recoverin's two domains. Impairment of Ca2+-binding in recoverin leads to a disturbance of the Ca2+-myristoyl switch and loss of its regulatory properties, i.e. inhibiton of rhodopsin kinase. We have engineered recoverin mutants with either of the two functional EF-hands disabled, but with a functional Ca2+-binding site in EF-hand 4. While a defect in EF-hand 2 could not be rescued by the additional EF-hand 4, the impairment of EF-hand 3 was powerfully compensated by Ca2+-binding to EF-hand 4. For example, the myristoylated form of the latter mutant bound to membranes in a Ca2+-dependent way and was able to inhibit rhodopsin kinase in a way similar to that of the wild-type protein. Thus, for recoverin to undergo a Ca2+-myristoyl switch, it is necessary and sufficient to have either of the two EF-hands in the second domain in a functional state. On the basis of these results and inspection of published three-dimensional structures of recoverin, we propose a model highlighting the mutual interdependence of sterical configurations in EF-hands 3 and 4 of recoverin. (C) 2003 Elsevier Science Ltd. All rights reserved

One of the Ca(2+) binding sites of recoverin exclusively controls interaction with rhodopsin kinase

Recoverin is a neuronal calcium sensor protein that controls the activity of rhodopsin kinase in a Ca(2+)-dependent manner. Mutations in the EF-hand Ca2+ binding sites are valuable tools for investigating the functional properties of recoverin. In the recoverin mutant E121Q (Rec E121Q ) the high-affinity Ca2+ binding site is disabled. The non-myristoylated form of Rec E121Q binds one Ca2+ via its second Ca(2+)-binding site (EF-hand 2), whereas the myristoylated variant does not bind Ca2+ at all. Binding of Ca2+ to non-myristoylated Rec E121Q apparently triggers exposure of apolar side chains, allowing for association with hydrophobic matrices. Likewise, an interaction surface for the recoverin target rhodopsin kinase is constituted upon Ca2+ binding to the non-acylated mutant. Structural changes resulting from Ca(2+)-occupation of EF-hand 2 in myristoylated and non-myristoylated recoverin variants are discussed in terms of critical conditions required for biological activity