87 research outputs found

    Study of the electro and thermophysical properties of composite ceramic materials containing nickel nanoparticles

    No full text
    The regularities in the behavior of the electrophysical and some thermophysical properties of composite ceramic materials containing both micro- and nanoparticles of nickel in the region of the percolation threshold have been studied. Certain regularities in the behavior of the electrical conductivity, dielectric constant, thermal conductivity, and thermoelectric power of composite ceramic materials as a function of the volume content of nickel particles are revealed. Near the percolation threshold, the experimental results of the behavior of the electrical conductivity and static permittivity as a function of the nickel volume content in these materials differ from the dependences calculated within the framework of the percolation theory in that the curve of the dependence of the permittivity has the form similar to the electrical conductivity curve. The origin of this discrepancy is explained by the formation of a continuous spatial structure of tunnel-connected conductors

    The David procedure after the Ross operation: case series

    Get PDF
    Pulmonary autograft in the aortic position provides high survival rate and quality of life for patients, low incidence of valve-related complications, and excellent hemodynamic characteristics both in the early and long-term period. However, in some patients in the long-term period, pulmonary autograft may dilate, which in turn is one of the reasons for reoperations. In patients who require surgery for annuloaortic ectasia with aortic valve (AV) regurgitation or aortic root aneurysm (or both) with normal AV leaflets, David procedure is considered.Aim. To analyze results of David procedure after a prior Ross operation.Material and methods. From April 2009 to December 2020, 212 Ross operations were performed on patients 18 years of age and older. The median age of the operated patients was 34 (27-45) years. In the long-term period, 10 (4,7%) patients required a second AV operation and 7 (3,3%) of them required another intervention on the ascending aorta due to aortic dilatation. Four out of 10 patients underwent David procedure. The follow-up period for patients after David procedure ranged from 2 to 84 months.Results. The age of patients ranged from 23 to 45 years. Three patients had hypertension. The follow-up period from Ross's operation to David's one was 26 to 140 months. All patients had enlarged aortic annulus from 27 to 30 mm. The duration of myocardial ischemia ranged from 87 to 142 minutes, while the duration of artificial circulation — from 119 to 165 minutes. The graft diameter was 30 mm in two patients and 32 mm in the remaining ones. The length of stay in intensive care unit ranged from 16 to 23 hours. In the early postoperative period, no one had following postoperative complications: acute renal failure requiring hemodialysis, perioperative myocardial injury, stroke, sternal infection, respiratory failure requiring mechanical ventilation for ≥24 hours, resternotomy for bleeding and tamponade. In addition, there were no in hospital deaths. All patients had no aortic regurgitation at the time of discharge. All patients are alive and there were no reoperations. In one patient, in the long-term period, there was a mild aortic regurgitation, while in three patients — there is no regurgitation.Conclusion. The presented case series show that David procedure can be performed safely and effectively in a significant number of patients requiring a second autograft surgery due to neosinus dilatation. In the medium term, the David procedure has shown good outcomes in these patients with 100% survival and no aortic regurgitation and reoperation

    Неоперабельный гепатоцеллюлярный рак — перспективы лекарственной терапии ленватинибом

    Get PDF
    There is a number of unresolved issues regarding the systemic therapy administration for hepatocellular carcinoma (HCC). Their solution is facilitated by accumulating real‑world study results. Lenvatinib therapy is a recognized drug with a good efficacy and safety profile for the treatment of HCC. Subanalyses of the REFLECT study showed that the absence of stratification by baseline AFP and baseline liver function, as well as the lack of options for subsequent drug therapy after lenvatinib, also affects the outcomes. Once these factors are taken into account, the hypothesis of superiority of lenvatinib to sorafenib and other drugs can be tested. Real‑world clinical studies have demonstrated positive results of lenvatinib therapy in patients with Child‑Pugh class B liver function, provided recommendations on the sequence of systemic therapy after lenvatinib and on the use of lenvatinib in patients with BCLC stage B, along with considering the possibility of lenvatinib monotherapy and the prospects for its use in patients with nHCC. Further real‑world studies of lenvatinib for HCC in the Russian population are required.В подходах к назначению лекарственной терапии гепатоцеллюлярного рака (ГЦР) есть ряд еще нерешенных вопросов. Их решению способствует накопление результатов исследований в реальной клинической практике. Методом медикаментозной терапии ГЦР с хорошим профилем эффективности и безопасности признана терапия ленватинибом. В субанализах исследования REFLECT показано, что отсутствие стратификации по исходному уровню альфа-фетопротеина и оценке исходной функции печени, а также дефицит опций последующей после назначения ленватиниба медикаментозной терапии оказывают влияние на результаты. Учет этих факторов даст возможность проверить гипотезу превосходства терапии ленватинибом в сравнении с сорафенибом и другими препаратами. В исследованиях реальной клинической практики продемонстрированы положительные результаты применения ленватиниба у пациентов с нарушением функции печени класса B по шкале Чайлд-Пью, даны рекомендации по последовательности системной терапии после ленватиниба, применению ленватиниба у пациентов стадии BCLC B, а также рассмотрены возможности монотерапии ленватинибом и перспективы его применения у пациентов с нГЦК. Необходимы дальнейшие исследования ленватиниба при ГЦР в реальной клинической практике на российской популяции

    Pulmonary homograft dysfunction after Ross procedure in adults: a single center experience

    Get PDF
    The Ross procedure was first proposed by Donald Ross in 1967. Numerous studies show excellent long-term outcomes of the Ross operation. One of its disadvantages is the intervention on two valves due to pulmonary homograft dysfunction.Aim.  To study long-term outcomes of pulmonary homograft use after Ross operation (cumulative incidence of pulmonary homograft dysfunction, freedom from reoperation on pulmonary homograft, long-term survival, predictors of pulmonary homograft dysfunction) using data from one Russian center.Material  and  methods. A retrospective study included patients aged 18 years and older with aortic valve disease who underwent Ross procedure from April 2009 to December 2020 by a single surgeon. The age of the patients was 35 (26-44) years (men, 159 (75%)). Infective endocarditis as a cause of aortic valve pathology was diagnosed in 55 (26%) patients. Bicuspid aortic valve was diagnosed in 131 (62%) patients. The median follow-up period was 79 (26,5102,7) months.Results. Combined interventions were performed in 40 cases (18,9%). The modified Ross procedure was used in 54 (25,5%) cases (intra-aortic — 29, using Dacron tube graft — 25). Inhospital mortality was 0,5%. The 5- and 10-year allcause survival rates were 98,5% and 95,4%, while the 10-year cumulative pulmonary valve reoperation rate and pulmonary homograft dysfunction was 4,6% and 35,2%, respectively. The only factor affecting pulmonary homograft dysfunction was patient age ≤30 years (odds ratio =0,2 with 95% confidence interval: 0,06-0,7; p=0,02).Conclusion. Fresh pulmonary homografts have a low incidence of dysfunction and reintervention after Ross procedure. Young age is the only independent risk factor for pulmonary homograft dysfunction

    Сравнительная эффективность симультанных и этапных операций у пациентов с атеросклеротическим поражением сонных и коронарных артерий

    Get PDF
    Objective: comparative systematic analysis of clinical trials of staged and simultaneous approaches in the surgical treatment of combined carotid and coronary stenosis based on the literature search.Material and methods. A systematic literature search was performed in PubMed/MEDLINE, Google Scholar and Scopus using predefined acceptance criteria. To compare data of simultaneous and staged surgery cumulative indicators of heart attack, stroke and mortality, expressed as percentages and absolute numbers, were analyzed; the Mantel–Hensel formula and the χ2 method were used to assess the relative risk of major adverse cardio-cerebral events development and mortality.Results. The analysis included 7 studies containing one intervention (4 simultaneous and 3 stage methods). The risk of developing myocardial infarction was RR 0.13 (95% CI 0.02–0.67) for simultaneous tactics, and RR 7.79 (95% CI 1.5–40.43) for staged tactics (p˂0.005). The risk of stroke developing was RR 1.29 (95% CI 0.56–2.99) for a simultaneous approach, and RR 0.78 (95% CI 0.33–1.8) for stage approach (p˃0.05). The risk of mortality was RR 0.77 (95% CI 0.31–1.88) for simultaneous procedures, and RR 1.3 (95% CI 0.53–3.18) for staged procedures (p˃0.05).Conclusion. Staged tactics for combined carotid and coronary stenosis may be accompanied by a significantly higher risk of myocardial infarction. There was no statistically significant difference between the groups in terms of the risk of stroke and mortality, but there was a trend towards a higher risk of stroke in the simultaneous group and a higher risk of death from all causes in the staged group.Цель: сравнительный анализ клинических исследований этапного и симультанного подходов в хирургическом лечении сочетанных поражений каротидного и коронарного русла по данным литературы.Материал и методы. Был выполнен систематический поиск литературы в базе данных PubMed/MEDLINE, Google Scholar и Scopus с помощью предварительно определенных критериев приемлемости. Сравнивая данные симультанной хирургии с этапной хирургией, анализировали кумулятивные показатели частоты инфаркта, инсульта и летальности, выраженные в процентах и абсолютных цифрах. Для оценки относительного риска (related risk, RR) развития осложнений использовали формулу Мантеля–Хензеля и критерий χ2.Результаты. В анализ вошли 7 исследований, которые содержали одно вмешательство (4 симультанных и 3 этапных метода). Риск развития инфаркта миокарда: при симультанной тактике – RR 0,13 (95% ДИ 0,02–0,67), при этапной – RR 7,79 (95% ДИ 1,5-40,43) (р˂0,005). Риск развития инсульта: при симультанном подходе – RR 1,29 (95% ДИ 0,56–2,99), при этапном – RR 0,78 (95% ДИ 0,33–1,8) (р˃0,05). Риск летальности: при симультанных операциях – RR 0,77 (95% ДИ 0,31–1,88), при этапных – RR 1,3 (95% ДИ 0,53–3,18) (р˃0,05).Заключение. Этапная тактика при сочетанных стенозах каротидного и коронарного русла может сопровождаться достоверно более высоким риском развития инфаркта миокарда. В отношении риска развития инсульта и летальности статистически достоверной разницы между группами выявлено не было, но отмечена тенденция к более высокому риску инсульта в симультанной группе и более высокому риску смерти от всех причин в этапной группе

    Способы хирургического лечения сочетанных стенозов сонных и коронарных артерий. Систематический обзор

    Get PDF
    Aim of study. To determine the optimal tactics of surgical treatment of patients with combined stenosis of the carotid and coronary arteries by comparing the results of the simultaneous and staged approach according to the literature.Material and methods. A systematic literature search was performed in the PubMed and MEDLINE databases to compare the results of simultaneous and staged interventions for combined stenosis of the carotid and coronary arteries. The following keywords were used as a search query: (“combined coronary and carotid artery stenosis and simultaneous”), (“combined coronary and carotid artery stenosis and staged”), (“combined coronary and carotid artery stenosis and cost”). We compared the results of simultaneous (interventions on the vessels of both systems are performed simultaneously) and staged operations (interventions are performed alternately, with a time interval from 2 to 160 days). References from included studies were also manually reviewed. The search was conducted by two independent experts (S.L., S.N.), and any disagreement was resolved by the clinical expert (A.A.).Results. A literature search identified 198 potentially relevant studies. A total of 13 studies met the inclusion criteria, of which 5 included two interventions. This systematic analysis includes the results of treatment of 43,758 patients with combined stenosis of the carotid and coronary arteries, who underwent staged or simultaneous revascularization of the vessels of the carotid and coronary flow. Perioperative neurological complications in the group of staged operations were observed somewhat more often than in the group of simultaneous interventions (3.2% versus 4.22%; p=0.8), myocardial infarction was observed with a frequency of 1.5% in the group of simultaneous interventions, and 2.5% (p=0.5) in the group of staged interventions. The mortality rate after simultaneous and staged interventions was 3.9% and 3.6%, respectively, with a fairly high spread in the study groups (p=0.5). Data analysis showed that simultaneous interventions did not affect the incidence of neurological, cardiac complications, and deaths (OR (odds ratio) 1.02; 95% CI (confidence interval) — 0.98–1.14, p = 0, 69; OR — 1.26; 95% CI — 0.66-2.41; p=0.48; and OR — 0.97; 95% CI — 0.67-1.38; p=0.85 — respectively).Conclusion. 1. The cumulative incidence of neurological and cardiac complications and mortality in staged tactics, according to observational studies included in this systematic review, is 4.2%; 2.6% and 3.6%, respectively (p>0.05). 2. The cumulative incidence of neurological and cardiac complications and mortality with simultaneous tactics according to observational studies included in this systematic review is 3.3%; 1.5% and 3.9%, respectively (p>0.05). 3. Given the relatively low risk of developing myocardial infarction (OR — 1.26; 95% CI — 0.66–2.41; I2 — 94%), the low risk of developing neurological complications (OR 1.02; 95% CI — 0,98–1.14; I2=75%), and deaths (OR — 0.97; 95% CI — 0.67–1.38; I2 — 76%) — (p>0.05), with simultaneous interventions, it can be concluded that simultaneous interventions may be the method of choice for surgical treatment for combined stenosis of the carotid and coronary arteries.Цель исследования. Определить оптимальную тактику хирургического лечения пациентов с сочетанными стенозами сонных и коронарных артерий путем сравнения результатов симультанного и этапного подхода по данным литературы.Материал и методы. Выполнен систематический поиск литературы в базах данных PubMed и MEDLINE для сравнения, данных результатов симультанных и этапных вмешательств при сочетанных стенозах сонных и коронарных артерий. В качестве поискового запроса использовали следующие ключевые слова: (“combined coronary and carotid artery stenosis and simultaneous”), (“combined coronary and carotid artery stenosis and staged”), (“combined coronary and carotid artery stenosis and cost”). Сравнивали результаты симультанных (вмешательства на сосудах обоих бассейнов выполняются одновременно) и этапных операций (вмешательства выполняются поочередно, с интервалом времени от 2 до 160 суток). Ссылки из включенных исследований были также рассмотрены вручную. Поиск проводили двое независимых специалистов (С.Л., С.Н.), любые разногласия разрешались клиническим экспертом (А.А.).Результаты. Поиск литературы позволил выявить 198 потенциально подходящих исследований. В итоге 13 исследований соответствовали критериям включения, из которых 5 содержали две интервенции. Данный систематический анализ включает результаты лечения 43 758 пациентов с сочетанными стенозами сонных и коронарных артерий, которым произведена этапная или симультанная реваскуляризация сосудов сонного и коронарного русла. Периоперационные неврологические осложнения в группе этапных операций наблюдались несколько чаще, чем в группе симультанных вмешательств (3,2% против 4,22%; р=0,8), инфаркт миокарда отмечен с частотой в группе симультанных вмешательств 1,5%, и в группе этапных вмешательств — 2,5% (р=0,5). Частота летальности после симультанных и этапных вмешательств составила 3,9% и 3,6% соответственно при достаточно высоком разбросе в группах исследования (р=0,5). Анализ данных показал, что симультанные вмешательства не влияют на частоту развития неврологических, кардиальных осложнений и смертельных исходов (ОШ (отношение шансов) 1,02; 95% ДИ (доверительный интервал) — 0,98–1,14, p=0,69; ОШ — 1,26; 95% ДИ — 0,66–2,41; р=0,48; и ОШ — 0,97; 95% ДИ — 0,67–1,38; р=0,85 — соответственно).Выводы. 1. Кумулятивная частота неврологических и кардиологических осложнений и летальности при этапной тактике по данным обсервационных исследований, включенных в данный систематический обзор, составляет 4,2%; 2,6% и 3,6% соответственно (р>0,05). 2. Кумулятивная частота неврологических и кардиологических осложнений и летальности при симультанной тактике по данным обсервационных исследований, включенных в данный систематический обзор, составляет 3,3%; 1,5% и 3,9% соответственно (р>0,05). 3. Учитывая относительно низкий риск развития инфарктов миокарда (ОШ — 1,26; 95% ДИ — 0,66-2,41; I2 — 94%), низкий риск развития неврологических осложнений (ОШ 1,02; 95% ДИ — 0,98-1,14; I2=75%) и летальных исходов (ОШ — 0,97; 95% ДИ — 0,67–1,38; I2 — 76%) — (р>0,05) при симультанных вмешательствах, можно сделать заключение: симультанные вмешательства могут являться способом выбора хирургического лечения при сочетанных стенозах сонных и коронарных артерий

    The state of the art of biospeleology in Russia and other countries of the former Soviet Union: A review of the cave (endogean) invertebrate fauna. 3. References

    No full text

    Direct-acting antiviral agents for hepatitis C virus-mixed cryoglobulinaemia: dissociated virological and haematological responses

    No full text
    The hepatitis C virus-positive (HCV+) mixed cryoglobulinaemia (MC) is associated with haematological alterations such as monoclonal B-cell lymphocytosis or non-Hodgkin lymphomas (NHLs). Antiviral therapy for MC, based on interferon and ribavirin, has been shown to be able to eliminate the viral replication as well as the B-cell monoclonal alterations. Many studies have reported the efficacy of direct-acting antivirals (DAAs) in the treatment of HCV+ MC. However, some authors noticed the persistence of haematological diseases despite HCV eradication. To verify the effects of DAAs on B-cell proliferation, we evaluated 67 patients with HCV+ MC. Six patients had an overt NHL and 30% had monoclonal B-lymphocytosis. In 20% of the patients, the mutation L265P of the myeloid differentiation factor 88 (MYD88) gene was detected in peripheral blood. All patients had negative HCV viraemia at week 12; one had a breakthrough, while two cases relapsed. A complete clinical response of vasculitis was seen in 60% of the patients. Among the six patients with NHL, one showed a complete response, whereas in the others there were no changes in the number and size of the nodes. Among the patients carrying a clonal population in peripheral blood, only 22% became negative. These data indicate that DAAs are not able to eliminate the clonal alterations induced by HCV in a large proportion of cases

    Important problems in the diagnosis and treatment of primary sclerosing cholangitis (based on the Russian consensus on diagnosis and treatment autoimmune hepatitis. Moscow, 2018)

    No full text
    © 2019 Consilium Medikum. All rights reserved. The article is published based on the results of the Russian Consensus on the diagnosis and treatment of primary sclerosing cholangitis (PSC), discussed at the 44 th annual Scientific Session of the CNIIG "Personalized Medicine in the Era of Standards" (March 1, 2018). The aim of the review is to highlight the current issues of classification of diagnosis and treatment of patients with PSC, which causes the greatest interest of specialists. The urgency of the problem is determined by the multivariate nature of the clinical manifestations, by often asymptomatic flow, severe prognosis, complexity of diagnosis and insufficient study of PSC, the natural course of which in some cases can be considered as a function with many variables in terms of the nature and speed of progression with numerous possible clinical outcomes. In addition to progression to portal hypertension, cirrhosis and its complications, PSC can be accompanied by clinical manifestations of obstructive jaundice, bacterial cholangitis, cholangiocarcinoma and colorectal cancer. Magnetic resonance cholangiography is the main method of radial diagnostics of PSC, which allows to obtain an image of bile ducts in an un-invasive way. The use of liver biopsy is best justified when there is a suspicion of small-diameter PSC, autoimmune cross-syndrome PSC-AIG, IgG4-sclerosing cholangitis. Currently, a drug registered to treat primary sclerosing cholangitis which can significantly change the course and prognosis of the disease does not exist. There is no unified view on the effectiveness and usefulness of ursodeoxycholic acid and its dosage in PSC. Early diagnosis and determination of the phenotype of PSC is of clinical importance. It allows to determine the tactics of treatment, detection and prevention of complications

    Important problems in the diagnosis and treatment of primary sclerosing cholangitis (based on the Russian consensus on diagnosis and treatment autoimmune hepatitis. Moscow, 2018)

    No full text
    © 2019 Consilium Medikum. All rights reserved. The article is published based on the results of the Russian Consensus on the diagnosis and treatment of primary sclerosing cholangitis (PSC), discussed at the 44 th annual Scientific Session of the CNIIG "Personalized Medicine in the Era of Standards" (March 1, 2018). The aim of the review is to highlight the current issues of classification of diagnosis and treatment of patients with PSC, which causes the greatest interest of specialists. The urgency of the problem is determined by the multivariate nature of the clinical manifestations, by often asymptomatic flow, severe prognosis, complexity of diagnosis and insufficient study of PSC, the natural course of which in some cases can be considered as a function with many variables in terms of the nature and speed of progression with numerous possible clinical outcomes. In addition to progression to portal hypertension, cirrhosis and its complications, PSC can be accompanied by clinical manifestations of obstructive jaundice, bacterial cholangitis, cholangiocarcinoma and colorectal cancer. Magnetic resonance cholangiography is the main method of radial diagnostics of PSC, which allows to obtain an image of bile ducts in an un-invasive way. The use of liver biopsy is best justified when there is a suspicion of small-diameter PSC, autoimmune cross-syndrome PSC-AIG, IgG4-sclerosing cholangitis. Currently, a drug registered to treat primary sclerosing cholangitis which can significantly change the course and prognosis of the disease does not exist. There is no unified view on the effectiveness and usefulness of ursodeoxycholic acid and its dosage in PSC. Early diagnosis and determination of the phenotype of PSC is of clinical importance. It allows to determine the tactics of treatment, detection and prevention of complications
    corecore