Research on the impact of nano carbon fillers on the morphology of epoxy binder

ABSTRACT: Introduction. When developing a composite material, it is important to understand how the components included in its composition affect its properties. Fillers, by interacting with the matrix, can alter its initial structure, resulting in the composite acquiring characteristics different from the matrix. The high modifying ability of nanofillers is determined by their significant specific surface area. This allows for the total interfacial area between the matrix and the dispersed phase to be covered even with a relatively low concentration of particles, thereby enabling the use of a small amount of filler. Methods and materials. Composite materials with nano carbon fillers were investigated, including fullerenes, nanotubes, and graphene. Fractographic analysis of the tensile fracture surfaces of the samples was chosen to evaluate the structure of the composites, which allows determining the nature of the failure and the ability of the composite to restrain crack propagation. The microstructure of the composite materials, as well as the morphology of the reinforcing nano carbon fillers, were examined with a Tescan MIRA3 scanning electron microscope. Results and discussion. In a graphene composite, crack energy is dissipated through branching and elongation of the crack path. Carbon nanotubes, being embedded in the crack walls, hinder the opening of the crack edges. Crack energy is also consumed in overcoming friction forces during the extraction of nanotubes from the epoxy matrix. Agglomerates of fullerenes act as effective crack front arresters, forcing the crack to circumvent them, thereby creating new areas of fracture surfaces. This leads to an increase in the crack front length and the energy required for material failure. Conclusion. Adding nano-carbon fillers (graphene, CNT and fullerenes) as reinforcing components in the epoxy binder alters the structure. The study defines possible mechanisms for hardening of the composite materials due to adding the nano-carbon fillers

Acute Adhesive Small Bowel Obstruction: a Comparative Analysis of Open and Laparoscopic Surgery

Background. Acute adhesive small bowel obstruction (AASBO) is a common surgical emergency requiring immediate interventions. AASBO is a usual indication for both small bowel resection and adhesiolysis. Postoperative adhesions cause 60% of small bowel obstructions.Materials and methods. An analysis of treatment outcomes is presented for 197 acute adhesive small bowel obstruction patients; 63 patients had urgent laparotomy, and 134 were scheduled for laparoscopy. The examination included physical, laboratory, radiological methods (abdominal radiography, ultrasound, CT scan), laparoscopy and intra-abdominal pressure monitoring.Results and discussion. Of 134 patients scheduled for laparoscopic adhesiolysis, only 46.2% had laparoscopy completed, and 53.8% required conversion to laparotomy. The main rationale for conversion were massive adhesions, intraoperative haemodynamic instability, a need for intestinal decompression, as well as rare complications. Laparoscopic operations were reported with the lower vs. laparotomy rates of surgical complications (6.4  vs. 12.69%), mortality (6  vs. 6.3%), shorter hospital stays (6.5 vs. 12 days) and operation times (75 vs. 118 min, respectively).Conclusion. Laparoscopic surgery in acute adhesive small bowel obstruction was feasible in 31.47% patients and in 46.2% — after a diagnostic laparoscopy; however, a thorough patients selection for laparoscopic adhesiolysis is necessary. The first estimated should be the patient’s haemodynamic stability, the severities of condition, adhesions and comorbid cardiorespiratory pathology. Grade I—II adhesions are an indication for laparoscopic surgery

Особенности оказания хирургической помощи в условиях пандемии COVID-19 (обзор литературы)

Since March 2020, when COVID-19 pandemic was declared by WHO, the new coronavirus infection has spread widely around the world, claiming many lives and destroying the economies, social structures, and various aspects of people’s lives. The pandemic has had a major impact on health facilities, including the surgical service. The healthcare system had to completely reorganize its methods of work. The need to deploy a significant number of infectious disease beds necessitated the convertion of many medical organizations into Covid hospitals, with a reduction in surgical units and beds. The scheduled surgical operations were therefore cancelled and postponed. Emergency surgical care was provided as needed, albeit in a reduced scope. The number of patients seeking emergency surgical care decreased mainly due to the fear of contracting COVID-19. The data show that there is a significant increase in the number of perioperative complications and mortality, especially in patients with acute surgical pathology and co-occurring COVID-19. The paper presents the data from professional literature on the peculiarities of surgical care in the context of the coronavirus pandemic, changes in a number of obligatory indicators of the quality of surgical care for patients.С марта 2020 года – момента объявления ВОЗ пандемии COVID-19 – новая коронавирусная инфекция широко распространилась по всему миру, унося жизни многих людей и разрушая экономику, социальную структуру, различные стороны жизни населения. Пандемия оказала серьезное влияние на работу медицинских учреждений, в том числе на деятельность хирургической службы, после объявления ВОЗ пандемии. Система здравоохранения вынуждена была перестроить полностью свою работу. Потребность развертывания значительного числа инфекционных коек вызвала необходимость перепрофилирования многих медицинских организаций в ковид-госпитали с сокращением хирургических отделений и коек. Ввиду этого плановые операции были отменены и отсрочены. Экстренная хирургическая помощь оказывалась в необходимом объеме, хоть и в сокращенном варианте, в основном это связано со снижением количества больных, которые обращались за неотложной хирургической помощью из-за страха заразиться COVID-19. По литературным данным отмечается значительное повышение числа периоперационных осложнений и летальности, особенно у пациентов с острой хирургической патологией и сопутствующей COVID-19. В статье приведены данные специальной литературы по вопросам особенностей оказания хирургической помощи в условиях пандемии коронавирусной инфекции, изменение ряда облигатных показателей качества оказания хирургической помощи больным

Multiparametric optical bioimaging reveals the fate of epoxy crosslinked biomeshes in the mouse subcutaneous implantation model

Biomeshes based on decellularized bovine pericardium (DBP) are widely used in reconstructive surgery due to their wide availability and the attractive biomechanical properties. However, their efficacy in clinical applications is often affected by the uncontrolled immunogenicity and proteolytic degradation. To address this issue, we present here in vivo multiparametric imaging analysis of epoxy crosslinked DBPs to reveal their fate after implantation. We first analyzed the structure of the crosslinked DBP using scanning electron microscopy and evaluated proteolytic stability and cytotoxicity. Next, using combination of fluorescence and hypoxia imaging, X-ray computed microtomography and histology techniques we studied the fate of DBPs after subcutaneous implantation in animals. Our approach revealed high resistance to biodegradation, gradual remodeling of a surrounding tissue forming the connective tissue capsule and calcification of crosslinked DBPs. These changes were concomitant to the development of hypoxia in the samples within 3 weeks after implantation and subsequent induction of angiogenesis and vascularization. Collectively, presented approach provides new insights on the transplantation of the epoxy crosslinked biomeshes, the risks associated with its applications in soft-tissue reconstruction and can be transferred to studies of other types of implants

Острая спаечная кишечная непроходимость: сравнительный анализ открытых и лапароскопических операций

Background. Acute adhesive small bowel obstruction (AASBO) is a common surgical emergency requiring immediate interventions. AASBO is a usual indication for both small bowel resection and adhesiolysis. Postoperative adhesions cause 60% of small bowel obstructions.Materials and methods. An analysis of treatment outcomes is presented for 197 acute adhesive small bowel obstruction patients; 63 patients had urgent laparotomy, and 134 were scheduled for laparoscopy. The examination included physical, laboratory, radiological methods (abdominal radiography, ultrasound, CT scan), laparoscopy and intra-abdominal pressure monitoring.Results and discussion. Of 134 patients scheduled for laparoscopic adhesiolysis, only 46.2% had laparoscopy completed, and 53.8% required conversion to laparotomy. The main rationale for conversion were massive adhesions, intraoperative haemodynamic instability, a need for intestinal decompression, as well as rare complications. Laparoscopic operations were reported with the lower vs. laparotomy rates of surgical complications (6.4  vs. 12.69%), mortality (6  vs. 6.3%), shorter hospital stays (6.5 vs. 12 days) and operation times (75 vs. 118 min, respectively).Conclusion. Laparoscopic surgery in acute adhesive small bowel obstruction was feasible in 31.47% patients and in 46.2% — after a diagnostic laparoscopy; however, a thorough patients selection for laparoscopic adhesiolysis is necessary. The first estimated should be the patient’s haemodynamic stability, the severities of condition, adhesions and comorbid cardiorespiratory pathology. Grade I—II adhesions are an indication for laparoscopic surgery. Введение. Острая спаечная кишечная непроходимость (ОСКН) является одной из частых причин в экстренной хирургии, требующих выполнения неотложных оперативных вмешательств. ОСКН — наиболее частое показание как для резекции тонкой кишки, так и для адгезиолизиса. В 60 % причиной обструкции тонкой кишки являются послеоперационные спайки.Материалы и методы. Представлен анализ результатов лечения 197 больных с острой спаечной кишечной непроходимостью, из которых 63 пациентам была выполнена экстренная лапаротомия, 134 — планировали лапароскопические операции. В обследовании применяли физикальные, лабораторные, лучевые методы исследования (обзорная рентгенография живота, УЗИ, КТ), лапароскопию, мониторинг внутрибрюшного давления.Результаты и  обсуждение. Из 134  пациентов, запланированных на лапароскопический адгезиолизис, только у 46,2 % операция завершена лапароскопически, в 53,8 % потребовалась конверсия на лапаротомию. Основными причинами конверсии были массивный спаечный процесс, интраоперационная нестабильность гемодинамики, потребность в декомпрессии кишечника, редко — осложнения. При лапароскопических операциях отметили снижение частоты хирургических осложнений по сравнению с лапаротомией (6,4 и 12,69 %), летальности (6 и 6,3 %), сроков госпитализации (6,5 и 12 дней), сокращение продолжительности операций (75 и 118 минут соответственно).Заключение. Хирургическое лечение лапароскопическим методом больных с острой спаечной кишечной непроходимостью возможно у 31,47 % к их общему числу, в 46,2 % — после диагностической лапароскопии, но требуется тщательный отбор больных на лапароскопический адгезиолизис. Прежде всего необходимо оценить тяжесть состояния больных, стабильность гемодинамики, выраженность спаечного процесса и коморбидной кардиореспираторной патологии. Показанием к лапароскопическим операциям является спаечный процесс I– II степени.

Острый аппендицит: как часто выполняется «напрасная» аппендэктомия?

   Introduction. At present, medical practice lacks a unifi ed approach to the choice of therapeutic tactics for acute catarrhal appendicitis and therefore lacks understanding of negative appendectomy.   Aim. To study the incidence of negative appendectomy in acute appendicitis. Materials and methods. The methodology involved a retrospective analysis of the results of 1590 appendectomies performed from 2003 to 2005 and a prospective non-randomized study of 1112 patientsfor the period from 2018 to 2019. During the first observation period, the examination included physical and laboratory examinations, and in the second period, Alvaro scoring, ultrasound scan, and videolaparoscopy.   Results and discussion. In the first period, catarrhal forms of appendicitis were reported in 7.82 % of cases, while in the second period — in 3.04 %. The diagnoses were confi rmed pathohistologically in all cases.   Conclusion. No cases of performing negative appendectomy were reported, based on the results of clinical, endoscopic and pathomorphological examinations. However, the ambiguous interpretation of acute catarrhal appendicitis in the national clinical practice guidelines for acute appendicitis does not allow for unambiguous conclusions from the study.   Введение. На сегодня не существует общепринятого подхода в выборе лечебной тактики при остром катаральном аппендиците и, соответственно, понимания так называемой «напрасной» аппендэктомии.   Цель работы. Изучить частоту выполнения т. н. «напрасных» аппендэктомий при остром аппендиците.   Материалы и методы. Проведен ретроспективный анализ результатов 1590 аппендэктомий за 2003–2005 гг. и проспективное нерандомизированное исследование 1112 пациентов за 2018–2019 гг. За первый период наблюдения обследование включало физикальное, лабораторное исследования, во II период обследование по шкале Alvarado, УЗИ, видеолапароскопию.   Результаты и обсуждение. В первый период катаральные формы аппендицита были в 7,82 %, во II — 3,04 %, патогистологически во всех случаях диагнозы были подтверждены.   Заключение. Случаев выполнения «напрасных» аппендэктомий по результатам клинического, эндоскопического и патоморфологического исследований не выявлено, однако неоднозначная трактовка острого катарального аппендицита в национальных клинических рекомендациях по острому аппендициту не позволяет делать однозначные выводы из исследования

A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction

Background: Carbohydrates play a major role in cell signaling in many biological processes. We have developed a set of glycomimetic drugs that mimic the structure of carbohydrates and represent a novel source of therapeutics for endothelial dysfunction, a key initiating factor in cardiovascular complications. Purpose: Our objective was to determine the protective effects of small molecule glycomimetics against free fatty acid­induced endothelial dysfunction, focusing on nitric oxide (NO) and oxidative stress pathways. Methods: Four glycomimetics were synthesized by the stepwise transformation of 2,5­dihydroxybenzoic acid to a range of 2,5­substituted benzoic acid derivatives, incorporating the key sulfate groups to mimic the interactions of heparan sulfate. Endothelial function was assessed using acetylcholine­induced, endotheliumdependent relaxation in mouse thoracic aortic rings using wire myography. Human umbilical vein endothelial cell (HUVEC) behavior was evaluated in the presence or absence of the free fatty acid, palmitate, with or without glycomimetics (1µM). DAF­2 and H2DCF­DA assays were used to determine nitric oxide (NO) and reactive oxygen species (ROS) production, respectively. Lipid peroxidation colorimetric and antioxidant enzyme activity assays were also carried out. RT­PCR and western blotting were utilized to measure Akt, eNOS, Nrf­2, NQO­1 and HO­1 expression. Results: Ex vivo endothelium­dependent relaxation was significantly improved by the glycomimetics under palmitate­induced oxidative stress. In vitro studies showed that the glycomimetics protected HUVECs against the palmitate­induced oxidative stress and enhanced NO production. We demonstrate that the protective effects of pre­incubation with glycomimetics occurred via upregulation of Akt/eNOS signaling, activation of the Nrf2/ARE pathway, and suppression of ROS­induced lipid peroxidation. Conclusion: We have developed a novel set of small molecule glycomimetics that protect against free fatty acidinduced endothelial dysfunction and thus, represent a new category of therapeutic drugs to target endothelial damage, the first line of defense against cardiovascular disease

Hematological manifestations of systemic lupus erythematosus in the early stage: association with other symptoms of the disease and possible prognostic value

Objective: to assess the relationship between hematological manifestations of systemic lupus erythematosus (SLE) in the early stage of the disease and development of other syndromes and symptoms of the disease, as well as the nature and severity of internal organs damage during the subsequent five-year period.Subjects and methods. The analysis of data of examination of 89 patients with SLE during the five-year period was carried out. The frequency of clinical manifestations of SLE, the level of antinuclear and antiphospholipid antibodies, SLICC/ACR damage index (SDI) depending on the presence of hematological manifestations of SLE in the onset of the disease including leukopenia (LP), thrombocytopenia (TP) and autoimmune hemolytic anemia (AGA) were studied.Results and discussion. In the onset of SLE LP was observed in 21.3%, TP – in 26.9%, AGA – in 8.9% of patients. The presence of LP was associated with an increase of antibodies to SSA frequency, and TP – with more frequent detection of antibodies to Ro-52, cardiolipin and β-2-glycoprotein (p<0.05). Patients with TP in the onset of SLE compared with patients without hematological manifestations, had an increase (p<0.05) of the cumulative incidence of nephritis (83.3 and 42.9%), central nervous system lesions (70.8 and 26.5%), vasculitis (45.8 and 10.2%) and Libman-Sachs endocarditis (20.8 and 6.1%, respectively), which was accompanied by an increase of SDI values (median was 2.09 [2, 1.82; 2.21] and 1.12 [0.81; 1.32], p<0.05). In patients with LP, the cumulative incidence of pneumonitis and Sjogren's syndrome was increased in the onset of SLE compared with patients without hematological manifestations (15.8 vs 6.1% and 15.7 vs 2.0%, respectively, p<0.05).Conclusion. Presence of TP in the onset of SLE is a predictor of kidneys, central nervous system, peripheral vessels and heart valves damage during the next 5 years

POLYCYTHEMIA VERA IDENTIFIED IN A PATIENT WITH RESTENOSIS OF THE SUPERFICIAL FEMORAL ARTERY. CLINICAL CASE AND REVIEW OF THE LITERATURE

The article describes the clinical case of the first revealed vera polycythemia in a 67-year-old man admitted to a hospital in the hematological department of the Republican Clinical Hospital named after. G.G. Kuvatov, Ufa, about the restenosis of the superficial femoral artery. On admission, the patient’s main complaints were pain in the left leg, shortness of breath with physical exertion, headache, unstable blood pressure, numbness of hands, fatigue, general weakness. In addition, the patient was troubled by severe itching. When entering the objective status of the patient, attention was drawn to the hyperemia of the face and neck, injection of sclera, acrocyanosis, cyanotic shade of the oral mucosa, amputation stump of the lower left third of the thigh, necrotic area on the skin of the distal part of the middle finger of the right leg. After receiving laboratory and clinical data, as well as on the basis of patient complaints, a history of the disease and a clinical picture, the final clinical diagnosis was established: the vera polycythemia II B stage. Against the background of ongoing therapy, the patient noted improvement in general condition, stabilization of blood pressure, reduction of pain in the right leg, reduction of dyspnea, itching of the skin, improvement of sensitivity in the hands. According to laboratory data, positive dynamics was also revealed. This clinical observation emphasizes the need for timely diagnosis and continuous monitoring of the treatment of vera polycythemia with the help of clinical and laboratory-instrumental research methods, which is a prerequisite for correct prognosis of the course of the disease and for achieving maximum effectiveness of the therapy