Tubulin bond energies and microtubule biomechanics determined from nanoindentation in silico

Microtubules, the primary components of the chromosome segregation machinery, are stabilized by longitudinal and lateral non-covalent bonds between the tubulin subunits. However, the thermodynamics of these bonds and the microtubule physico-chemical properties are poorly understood. Here, we explore the biomechanics of microtubule polymers using multiscale computational modeling and nanoindentations in silico of a contiguous microtubule fragment. A close match between the simulated and experimental force-deformation spectra enabled us to correlate the microtubule biomechanics with dynamic structural transitions at the nanoscale. Our mechanical testing revealed that the compressed MT behaves as a system of rigid elements interconnected through a network of lateral and longitudinal elastic bonds. The initial regime of continuous elastic deformation of the microtubule is followed by the transition regime, during which the microtubule lattice undergoes discrete structural changes, which include first the reversible dissociation of lateral bonds followed by irreversible dissociation of the longitudinal bonds. We have determined the free energies of dissociation of the lateral (6.9+/-0.4 kcal/mol) and longitudinal (14.9+/-1.5 kcal/mol) tubulin-tubulin bonds. These values in conjunction with the large flexural rigidity of tubulin protofilaments obtained (18,000-26,000 pN*nm^2), support the idea that the disassembling microtubule is capable of generating a large mechanical force to move chromosomes during cell division. Our computational modeling offers a comprehensive quantitative platform to link molecular tubulin characteristics with the physiological behavior of microtubules. The developed in silico nanoindentation method provides a powerful tool for the exploration of biomechanical properties of other cytoskeletal and multiprotein assemblie

Дифференциация и субпопуляционный состав VEGFR2+ моноцитов крови и костного мозга при ишемической кардиомиопатии

Aim. To identify disturbances of differentiation and subpopulation composition of VEGFR2+ cells in the blood and bone marrow associated with the features of the cytokine profile in the blood and bone marrow in patients with coronary artery disease (CAD) with and without ischemic cardiomyopathy (ICM).Materials and methods. The study included 74 patients with СAD with and without ICM (30 and 44 people, respectively) and 18 healthy donors. In all patients with СAD, peripheral blood sampling was performed immediately before coronary artery bypass grafting, and bone marrow samples were taken during the surgery via a sternal incision. In the healthy donors, only peripheral blood sampling was performed. In the bone marrow and blood samples, the number of VEGFR2+ cells (CD14+VEGFR2+ cells) and their immunophenotypes CD14++CD16-VEGFR2+, CD14++CD16+VEGFR2+, CD14+CD16++VEGFR2+, and CD14+CD16-VEGFR2+ was determined by flow cytometry. Using enzyme-linked immunosorbent assay, the levels of VЕGF-А, TNFα, M-CSF, and IL-13, as well as the content of MCP-1 (only in the blood) and the M-CSF / IL-13 ratio (only in the bone marrow) were determined.Results. The content of CD14+VEGFR2+ cells in the blood of CAD patients with and without ICM was higher than normal values due to the greater number of CD14++CD16-VEGFR2+, CD14++CD16+VEGFR2+, and CD14+CD16++VEGFR2+. In the bone marrow of the patients with ICM, the content of CD14++CD16-VEGFR2+, CD14+CD16++VEGFR2+, and CD14+CD16-VEGFR2+ was lower than in patients with CAD without ICM, and the number of CD14++CD16+VEGFR2+ cells corresponded to that in the controls. Regardless of the presence of ICM in CAD, a high concentration of TNFα and normal levels of VEGF-A and IL-13 were observed in the blood. In CAD without ICM, an excess of MCP-1 and deficiency of M-CSF were revealed in the blood. In the bone marrow, the levels of VEGF-A, TNFα, M-CSF, and IL-13 were comparable between the groups of patients against the background of a decrease in the M-CSF / IL-13 ratio in the patients with ICM.Conclusion. Unlike CAD without cardiomyopathy, in ICM, no excess of VEGFR2+ cells and MCP-1 in the blood is observed, which hinders active migration of CD14+CD16++VEGFR2+ cells from the myeloid tissue, and a decrease in the M-CSF / IL-13 ratio in the bone marrow disrupts differentiation of other forms of VEGFR2+ cells, preventing vascular repair.Цель: установить нарушения дифференцировки и субпопуляционного состава VEGFR2+ моноцитов в крови и костном мозге во взаимосвязи с особенностями цитокинового профиля крови и костного мозга у больных ишемической болезнью сердца (ИБС), страдающих и не страдающих ишемической кардиомиопатией (ИКМП).Материалы и методы. В исследование вошли 74 больных ИБС, страдающих и не страдающих ИКМП (30 и 44 человека соответственно), и 18 здоровых доноров. У всех больных ИБС забор периферической крови производился непосредственно перед операцией коронарного шунтирования, а костного мозга – из разреза грудины во время операции. У здоровых доноров забирали только периферическую кровь.  В костном мозге и крови методом проточной цитофлуориметрии определяли численность VEGFR2+ моноцитов (CD14+VЕGFR2+ клеток) и их иммунофенотипов CD14++CD16-VEGFR2+, CD14++CD16+VEGFR2+, CD14+CD16++VEGFR2+, CD14+CD16-VEGFR2+, методом иммуноферментного анализа регистрировали концентрацию VЕGF-А, TNFα, M-CSF, IL-13, а также содержание MCP-1 (только в крови) и соотношение M-CSF/IL-13 (только в костном мозге).Результаты. Содержание CD14+VEGFR2+ клеток в крови у больных ИБС без кардиомиопатии и с ИКМП было выше нормы из-за большей численности CD14++CD16-VEGFR2+, CD14++CD16+VEGFR2+ и CD14+CD16++VEGFR2+ форм. В костном мозге у больных ИКМП содержание CD14++CD16-VEGFR2+, CD14+CD16++VEGFR2+ и CD14+CD16-VEGFR2+ форм было ниже, чем у больных ИБС без кардиомиопатии, а количество CD14++CD16+VEGFR2+ клеток соответствовало их числу в группе сравнения. Вне зависимости от наличия ИКМП при ИБС в крови отмечалась высокая концентрация TNFα, нормальный уровень VEGF-А и IL-13; при ИБС без кардиомиопатии – избыток МСР-1 и дефицит M-CSF в крови. В костном мозге концентрация VЕGF-А, TNFα, M-CSF, IL-13 была сопоставимой между группами больных на фоне снижения M-CSF/IL-13 у пациентов с ИКМП.Заключение. В отличие от ИБС без кардиомиопатии при ИКМП не формируется избыток VEGFR2+ моноцитов и МСР-1 в крови, что затрудняет активную миграцию CD14+CD16++VEGFR2+ клеток из миелоидной ткани, а снижение M-CSF/IL-13 в костном мозге нарушает дифференцировку остальных форм VEGFR2+ моноцитов, препятствуя репарации сосудов

ПОСЛЕОПЕРАЦИОННЫЕ ОСЛОЖНЕНИЯ РЕКОНСТРУКТИВНО-ВОССТАНОВИТЕЛЬНЫХ ОПЕРАЦИЙ У БОЛЬНЫХ ОПУХОЛЯМИ ГОЛОВЫ И ШЕИ

The main goal of reconstructive surgery is to improve the quality of life of patients who have undergone surgery. However, recurrences and postoperative complications after such surgeries pose a serious challenge.The purpose of the study was to evaluate immediate surgical outcomes in head and neck cancer patients who underwent reconstructive surgery following tumor resection, as well as to analyze the causes of postoperative complications.Material and Methods. Immediate treatment outcomes were analyzed in 272 head and neck cancer patients, who were treated from 2008 to 2018. All patients were divided into 2 groups. Group I consisted of 172 patients, who underwent radical surgery and reconstruction. Group II comprised 100 patients, who underwent radical surgery alone. The groups were matched by stage, gender, age, previous treatment, and tumor location.Results. The incidence of recurrence was lower in Group I than in Group II (19 % versus 32 %, p>0,05). Postoperative complications occurred in 14 % of patients who underwent reconstruction of postoperative defects with rotation flaps and in 35 % of patients who underwent reconstruction with free revascularized flaps (p<0,05). The rate of complications was higher in patients undergoing maxillary and mandibular reconstructions (39,6 %) than in patients undergoing reconstructions of the other parts of the head and neck (23,7 %) (p<0,05). Patients who received chemoradiotherapy had higher rate of postoperative complications than those who had no neoadjuvant treatment (37 % versus 22 %, p>0,05).Conclusion. Knowledge of the factors that have a significant impact on the likelihood of developing postoperative complications after reconstructive surgeries makes it possible to take measures to prevent  them. Основной целью реконструктивно-пластических операций является улучшение качества жизни прооперированных больных. Однако возникающие рецидивы и  послеоперационные осложнения при подобных операциях являются значимой проблемой и требуют дальнейшего изучения. Целью исследования явились оценка непосредственных результатов хирургического лечения больных злокачественными новообразованиями головы и шеи с реконструктивно-пластическим компонентом и анализ причин возникновения  послеоперационных осложнений. Материал и методы. Проведен анализ непосредственных результатов лечения 272 больных злокачественными опухолями головы и шеи за период с 2008 по 2018 г., которые были разделены на 2 группы. В первую группу (n=172) вошли больные,  которым вместе с радикальным удалением опухоли был выполнен реконструктивно- пластический этап; во вторую группу (n=100) – пациенты, которым проведена радикальная операция без пластического этапа. Группы были сопоставимы по стадии, полу, возрасту, предшествующему лечению и локализации опухолевого процесса. Результаты. По данным исследования отмечена меньшая частота продолженного роста опухоли в группе с реконструктивно-пластическим этапом – 19 % больных, по  сравнению с контрольной группой – 32 % (p>0,05). Установлено, что при использовании ротированных лоскутов послеоперационные осложнения возникли в 14  %, а свободных реваскуляризированных лоскутов – в 35 % случаев (p<0,05). Реконструкция верхней и нижней челюсти сопровождается более частым развитием осложнений (39,6 %), чем устранение дефектов в других областях головы и шеи (23,7 %) (p<0,05). У больных, получивших химиолучевое лечение, послеоперационные  осложнения наблюдались чаще, чем у пациентов без неоадъювантного лечения, – в 37 % и 22 % случаев соответственно (p>0,05). Заключение. Знание факторов, оказывающих значимое влияние на вероятность развития послеоперационных осложнений при реконструктивно-пластических операциях, дает возможность проводить эффективные мероприятия по их профилактике

Molecular Genetic Analysis of the Complete Genome of Tick-Borne Encephalitis Virus (Siberia Subtype): Modern Kolarovo-2008 Isolate

Determined is the complete genome sequence of Kolarovo-2008 strain (Siberia subtype) of Tick-borne encephalitis virus (TBEV), isolated from a tick in the suburbs of the Tomsk city. Nucleotide sequence analysis testifies of the fact that the level of genetic differences within the Siberian subtype of TBEV amounts to 10 % of the nucleotide sequence and to 7 % of amino-acid sequence for certain virus genes. 3'-HTO of the genome of Siberian subtype has the highest rate of variability and the homology level ranging from 65 to 97 %. Kolarovo-2008 and Vasilchenko (isolated in Novosibirsk in 1969) strains have the highest level of genome homology. The level of dissimilarity between the two Tomsk strains is substantially higher: the total number of amino-acid substitutions in Tomsk Zausaev and Kolarovo-2008 strains equals to 124, and 3'HTO level of homology is 79 %. Identified genetic variability of the Siberian subtype of TBEV is of a great importance for further development and enhancement of tick-borne encephalitis virus diagnostics

Особенности электрофизиологической активности коры больших полушарий мозга у детей с артрогрипозом

Background. Arthrogryposis is one of the most severe congenital abnormalities of the musculoskeletal system characterized by 2 or more contractures of the large joints, muscle and anterior grey column pathology. One of the main problems making selfcare limited or impossible for the patients is an absence of the active movements in the joints of the upper extremities which can be restored through autologous transplantation from the various donor areas. Processes of the rehabilitation after these operations are associated with neuronal remodeling in the central nervous system both in the spinal cord and the brain, in the cortial regions in particular.The objective is to evaluate possible reflection of arthrogryposis in the amplitude and neurodynamical characteristics of the electroencephalogram (EEG) in children.Materials and methods. Electrophysiological characteristics of the cerebral cortex in children with arthrogryposis and healthy children of the same age were examined. Such EEG characteristics as power and long-range temporal correlations (evaluation of the neuronal activity dynamics) in ranges of 4–8, 8–12, and 12–16 Hz were measured. The results were evaluated in accordance with clinical scales.Results. Data analysis has shown that children with arthrogryposis have significantly decreased EEG power in all of the studied ranges compared to healthy children. Additionally, a significant correlation between EEG power and the level of restoration of motor functions in the upper extremities after autologous transplantation of various muscle groups in the position of the biceps was observed. The obtained results reflect correlation between the electrophysiological parameters of the cerebral cortex and processes associated with arthrogryposis pathology. However, neurodynamical parameters in children with arthrogryposis are similar to those in healthy children. The results allow to state that arthrogryposis is reflected through decreased electrical activity of the cerebral cortex in 4–16 Hz range with preservation of neurodynamic characteristics typical for disease-free children.Conclusion. In this study, a significant difference in EEG power in 4–8, 8–12, and 12–16 Hz ranges between children with arthrogryposis and healthy children was demonstrated. However, there was no difference in such an important neurodynamical characteristic as longrange temporal correlations. It is possible that decreased amplitude of EEG rhythms in children with arthrogryposis is caused by their lower motor activity in general.Введение. Артрогрипоз – один из наиболее тяжелых врожденных пороков развития опорно-двигательного аппарата, характеризующийся наличием 2 и более контрактур крупных суставов, поражением мышц, а также передних рогов спинного мозга. Одной из основных проблем, обусловливающих ограничение или невозможность самообслуживания пациентов, является отсутствие активных движений в суставах верхних конечностей, которое восстанавливается путем аутотрансплантации мышц различных донорских областей. Процессы реабилитации после таких операций связаны в том числе и с нейрональными перестройками в центральной нервной системе как в спинном, так и в головном мозге, в частности в корковых его отделах.Цель исследования – оценить возможное отражение заболевания артрогрипозом у детей в амплитудных и нейродинамических показателях электроэнцефалограммы (ЭЭГ).Материалы и методы. Изучали электрофизиологические показатели активности коры головного мозга у детей с диагнозом артрогрипоза и здоровых детей сходного возраста. Оценивали такие показатели ЭЭГ, как мощность и длинновременные корреляции (метод оценки динамики нейрональной активности) в диапазонах 4–8, 8–12 и 12–16 Гц. Поражения оценивали на основе клинических шкал.Результаты. Анализ данных показал, что у детей с артрогрипозом, по сравнению с детьми без патологий, имеется достоверное снижение мощности ЭЭГ по всем исследованным частотным диапазонам. Кроме того, продемонстрирована достоверная корреляция мощности ЭЭГ со степенью восстановления двигательных функций верхних конечностей после операций по аутотрансплантации различных групп мышц в позицию двуглавой мышцы плеча. Полученные результаты отражают корреляцию электрофизиологических параметров коры головного мозга с процессами, связанными с патологией артрогрипоза. При этом нейродинамические параметры у детей с артрогрипозом не отличаются от таковых у здоровых детей. По результатам можно констатировать факт отражения заболевания артрогрипозом в снижении электрической активности коры больших полушарий головного мозга в частотном диапазоне 4–16 Гц при сохранении нейродинамических показателей, сходных с группой детей без заболевания.Заключение. В данной работе показано достоверное отличие мощности ЭЭГ в диапазонах 4–8, 8–12 и 12–16 Гц у детей с артрогрипозом и здоровых детей. Однако разницы в таком важном нейродинамическом показателе, как длинновременные корреляции, не обнаружено. Возможно, факт снижения амплитуды ритмов в ЭЭГ у больных детей объясняется их более низкой общей моторной активностью

Estímulo no crescimento e na hidrólise de atp em raízes de alface tratadas com humatos de vermicomposto: ii - efeito da fonte de vermicomposto.

Um dos fatores mais limitantes para a produção de vermicomposto é a disponibilidade de esterco. Neste trabalho, foi avaliado o efeito da substituição parcial do esterco por bagaço de cana e por resíduos de leguminosa (Gliricidia sepium) na vermicompostagem sobre a qualidade do vermicomposto e sobre a bioatividade dos humatos, avaliadas por meio da análise do crescimento radicular e da atividade das bombas de H+ isoladas de raízes de alface. A substituição do esterco por bagaço de cana e por resíduos de leguminosas não acarretou prejuízo às características químicas dos vermicompostos. No entanto, os humatos isolados dos diferentes vermicompostos apresentaram características químicas distintas,tais como: acidez e propriedades óticas distintas. Os humatos produzidos a partir de esterco de bovino e da mistura esterco bovino + bagaço proporcionaram maiores estímulos no crescimento radicular das plantas de alface, sendo os mais indicados para uso na forma solúvel. A inclusão de resíduos de leguminosas no processo de vermicompostagem produziu humatos sem efeito sobre o desenvolvimento das raízes de alface

Estímulo no crescimento e na hidrólise de ATP em raízes de alface tratadas com humatos de vermicomposto: i - efeito da concentração.

O vermicomposto contém uma concentração elevada de substâncias húmicas e já é bem conhecido o efeito do seu uso sobre as propriedades do solo. No entanto,a ação direta das substâncias húmicas sobre o metabolismo das plantas é menos conhecida. O objetivo deste trabalho foi avaliar o uso de humatos extraídos de vermicomposto de esterco de curral com KOH 0,1 mol L-1 sobre o desenvolvimento e metabolismo de ATP em plântulas de alface. Após a germinação, plântulas de alface foram tratadas com os humatos em concentrações que variaram de 0 a 100 mg L-1 de C, durante quinze dias. Foram avaliados o crescimento da raiz e a atividade das bombas de H+ isoladas da fração microssomal do sistema radicular. Foi observado aumento na matéria fresca e seca do sistema radicular, bem como no número de sítios de mitose, raízes emergidas do eixo principal, na área e no comprimento radiculares, com o uso do humato na concentração de 25 mg L-1 de C. Também foi observado, nessa concentração, aumento significativo na hidrólise de ATP pelas bombas de H+, responsáveis pela geração de energia necessária à absorção de íons e pelo crescimento celular

European registry on the management of helicobacter pylori infection (HP-EUREG protocol): The first results of Russian centers

Aim: To assess the clinical practice of diagnosis and treatment in patients with Helicobacter pylori infection and to compare this practice with the international guidelines in the European Registry on the management of Helicobacter pylori infection, Hp-EuReg protocol), a multicenter prospective observational study initiated by the European Helicobacter and Microbiota Study Group. Materials and methods: The data of 813 patients infected with H. pylori and entered in the Hp-EuReg register by the Russian centers in 2013-2015 were analyzed. Results: The most common methods for the primary diagnosis of H. pylori infection are histology (40.3%), rapid urease test (35.7%), and serology (17.2%). The duration of H. pylori eradication therapy was 7, 10, and 14 days in 18.0, 49.3, and 25.1%, respectively. To monitor the effectiveness of treatment, the investigators used a histological examination (34%), a urea breath test (27.3%), H. pylori stool antigen (22.8%), and a rapid urease test (16.3%). A serological test was carried out in 2.5% of the cases. No monitoring was done in 13.5% of the patients. The average eradication efficiency was 82.6%. If the therapy was ineffective, 80% of physicians did not intend to prescribe a new cycle of treatment. Conclusion: Significant differences were found between clinical practice and the current guidelines

A 300-year record of sedimentation in a small tilled catena in Hungary based on δ13C, δ15N, and C/N distribution

Purpose Soil erosion is one of the most serious hazards that endanger sustainable food production. Moreover, it has marked effects on soil organic carbon (SOC) with direct links to global warming. At the same time, soil organic matter (SOM) changes in composition and space could influence these processes. The aim of this study was to predict soil erosion and sedimentation volume and dynamics on a typical hilly cropland area of Hungary due to forest clearance in the early eighteenth century. Materials and methods Horizontal soil samples were taken along two parallel intensively cultivated complex convex-concave slopes from the eroded upper parts at mid-slope positions and from sedimentation in toe-slopes. Samples were measured for SOC, total nitrogen (TN) content, and SOMcompounds (δ13C, δ15N, and photometric indexes). They were compared to the horizons of an in situ non-eroded profile under continuous forest. On the depositional profile cores, soil depth prior to sedimentation was calculated by the determination of sediment thickness. Results and discussion Peaks of SOC in the sedimentation profiles indicated thicker initial profiles, while peaks in C/N ratio and δ13C distribution showed the original surface to be ~ 20 cm lower. Peaks of SOC were presumed to be the results of deposition of SOC-enriched soil from the upper slope transported by selective erosion of finer particles (silts and clays). Therefore, changes in δ13C values due to tillage and delivery would fingerprint the original surface much better under the sedimentation scenario than SOC content. Distribution of δ13C also suggests that the main sedimentation phase occurred immediately after forest clearance and before the start of intense cultivation with maize. Conclusions This highlights the role of relief in sheet erosion intensity compared to intensive cultivation. Patterns of δ13C indicate the original soil surface, even in profiles deposited as sediment centuries ago. The δ13C and C/N decrease in buried in situ profiles had the same tendency as recent forest soil, indicating constant SOM quality distribution after burial. Accordingly, microbiological activity, root uptake, and metabolism have not been effective enough to modify initial soil properties