Self-organization of conducting pathways explains electrical wave propagation in cardiac tissues with high fraction of nonconducting cells

Cardiac fibrosis occurs in many forms of heart disease and is considered to be one of the main arrhythmogenic factors. Regions with a high density of fibroblasts are likely to cause blocks of wave propagation that give rise to dangerous cardiac arrhythmias. Therefore, studies of the wave propagation through these regions are very important, yet the precise mechanisms leading to arrhythmia formation in fibrotic cardiac tissue remain poorly understood. Particularly, it is not clear how wave propagation is organized at the cellular level, as experiments show that the regions with a high percentage of fibroblasts (65-75%) are still conducting electrical signals, whereas geometric analysis of randomly distributed conducting and non-conducting cells predicts connectivity loss at 40% at the most (percolation threshold). To address this question, we used a joint in vitro-in silico approach, which combined experiments in neonatal rat cardiac monolayers with morphological and electrophysiological computer simulations. We have shown that the main reason for sustainable wave propagation in highly fibrotic samples is the formation of a branching network of cardiomyocytes. We have successfully reproduced the morphology of conductive pathways in computer modelling, assuming that cardiomyocytes align their cytoskeletons to fuse into cardiac syncytium. The electrophysiological properties of the monolayers, such as conduction velocity, conduction blocks and wave fractionation, were reproduced as well. In a virtual cardiac tissue, we have also examined the wave propagation at the subcellular level, detected wavebreaks formation and its relation to the structure of fibrosis and, thus, analysed the processes leading to the onset of arrhythmias. © 2019 Kudryashova et al

Use of Sorghum for Enhancing the Biodiversity and Nutritional Value of Semi-Desert Pasture Ecosystems

The article presents the results of studies on the adaptive potential of sorghum used for restoration of degraded pasture ecosystems, increasing their biodiversity and nutritional value. The region chosen for the experiment is a semi-desert arid part of southern Russia. The aridity coefficient is 0.11–0.30 which is typical of the arid zone. The annual volume of precipitation is 125-265 mm. Two varieties of sorghum – Travinka and Caravan – were studied. They were grown with different thickness: 10 thousand, 20 thousand and 40 thousand plants per 1 hectare. During the growing season, there was soil and atmospheric drought. The best indicators of green mass yield were recorded for Travinka for the variant “40 thousand plants per hectare – 7.9 tons per hectare, and for Caravan for the variant “20 thousand plants per hecrate – 3.9 tons per hectare. Compared with natural pasture, sorghum productivity is 18 times higher by green mass yield and 26 times higher by dry mass yield (the best options). The analysis of the chemical composition and nutritional value of sorghum showed that compared to the plants of natural pasture, sorghum is a more nutritious fodder plant. Its nutritional value is more by 0.24 feed units per 1 kg and by 1.9 % by the mass of crude protein. It is better than other plants by the content of sugar content (79 g per 1 kg) and macronutrients

ROLE OF CYTOXIC T-LYMPHOCYTES IN THE PATHOGENESIS OF PRETERM BIRTH

Currently, the existence of a wide range of subpopulations of CD8+T-lymphocytes has been revealed, among which there are subpopulations of naive and effector cells, as well as memory cells. CD8+T-lymphocytes are thought to be a population of lymphocytes with high cytotoxic activity, which is of extreme importance during pregnancy. Given that each subpopulation is characterized by a set of produced mediators, surface and intracellular markers, we can assume their role in the pathogenesis of preterm birth. This determined the need to investigate the role of naive cells, effector cells, and memory cells in the development of spontaneous preterm birth. Data on the content of naive CD8+-lymphocytes in the peripheral blood of women with threatened preterm birth are practically absent. It was found that the infiltration of CD8+-lymphocytes in the area of uteroplacental contact was associated with the development of timely delivery. Chronic chorioamnionitis is the most common condition in idiopathic preterm birth and is characterized by the infiltration of maternal CD8+Tcells into the chorioamniotic membranes. Currently, it is believed that chronic inflammatory lesions of the placenta represent maternal antifetal rejection. This led to the study of the role of these cells in the pathogenesis of preterm birth. Purpose. To establish a possible pathogenetic mechanism of preterm birth in women with threatened preterm birth on the basis of the revealed features of differentiation and functional activity of CD8+- lymphocytes at the systemic levelMaterials and methods. The survey of women was carried out on the basis of the Federal State Budgetary Institution “V. Gorodkov Ivanovo Research Institute of Maternity and Childhood” of the Ministry of Health of the Russian Federation. A total of 126 women were examined, which were retrospectively divided into 2 main groups – women with threatened preterm birth(n = 68), which was divided into 2 subgroups – with the outcome of pregnancy preterm birth (n = 30) and timely delivery (n = 38). The control group included 58 women with uncomplicated pregnancy and who gave birth on time. In the CD8+-lymphocyte population, the content of central – Tcm (CD45RACD62L+), preterminally differentiated-Tem (CD45RACD62L- ) and terminally differentiated-Temra (CD45RA+CD62L- ) memory cells was determined. In all memory cell populations, the content of cells producing Granzyme B intracellularly was determined. The studies were performed using monoclonal antibodies (mAT) by flow cytometry on a FACSCanto II cytometer using the FACSDiva software (Becton Dickinson, USA).The analysis of the features of the relative content of CD8+-lymphocytes in the main group of women, depending on the outcome of pregnancy, was carried out. When comparing patients with a clinic of threatened preterm birth, whose pregnancy ended prematurely, a higher content of CD8+-lymphocytes was revealed than in group c of women who gave birth in a timely manner, which indicates a high stimulation of cytotoxic T-lymphocytes in this group of women. With threatening preterm birth, there is an increase in the content of naive CD8+-lymphocytes in the peripheral blood. Data on the content of naive CD8+-lymphocytes in the peripheral blood of women with threatened preterm birth are practically absent. The increase in CD8+Tn levels is more pronounced in the subgroup of women with a favorable pregnancy outcome. Given this fact, it can be assumed that in women with preterm birth, a lower CD8+Tn is associated with their increased differentiation into effector T-lymphocytes with their subsequent migration to the placental zone. This process could determine the observed decrease in the level of terminally differentiated granzyme-producing CD8+-lymphocytes in a subgroup of women with a pregnancy outcome of preterm birth, which coincided with the literature data

Over-expression of Oct4 and Sox2 transcription factors enhances differentiation of human umbilical cord blood cells in vivo

Gene and cell-based therapies comprise innovative aspects of regenerative medicine. Even though stem cells represent a highly potential therapeutic strategy, their wide-spread exploitation is marred by ethical concerns, potential for malignant transformation and a plethora of other technical issues, largely restricting their use to experimental studies. Utilizing genetically modified human umbilical cord blood mono-nuclear cells (hUCB-MCs), this communication reports enhanced differentiation of transplants in a mouse model of amyotrophic lateral sclerosis (ALS). Over-expressing Oct4 and Sox2 induced production of neural marker PGP9.5, as well as transformation of hUCB-MCs into micro-glial and endothelial lines in ALS spinal cords. In addition to producing new nerve cells, providing degenerated areas with trophic factors and neo-vascularisation might prevent and even reverse progressive loss of moto-neurons and skeletal muscle paralysis. © 2014 Elsevier Inc. All rights reserved

Over-expression of Oct4 and Sox2 transcription factors enhances differentiation of human umbilical cord blood cells in vivo

© 2014 Elsevier Inc. All rights reserved. Gene and cell-based therapies comprise innovative aspects of regenerative medicine. Even though stem cells represent a highly potential therapeutic strategy, their wide-spread exploitation is marred by ethical concerns, potential for malignant transformation and a plethora of other technical issues, largely restricting their use to experimental studies. Utilizing genetically modified human umbilical cord blood mono-nuclear cells (hUCB-MCs), this communication reports enhanced differentiation of transplants in a mouse model of amyotrophic lateral sclerosis (ALS). Over-expressing Oct4 and Sox2 induced production of neural marker PGP9.5, as well as transformation of hUCB-MCs into micro-glial and endothelial lines in ALS spinal cords. In addition to producing new nerve cells, providing degenerated areas with trophic factors and neo-vascularisation might prevent and even reverse progressive loss of moto-neurons and skeletal muscle paralysis

Human umbilical cord blood mononuclear cells transfected with dual cassette plasmids (VEGF + neurotrophic factor) for the treatment of amyotrophic lateral sclerosis

To increase the viability of neural cells in neurodegenerative diseases, after neurotraumas and ischemic strokes the most important neurotrophic and neuroprotective factors, which can be used as therapeutic agents were identified in long-term studies in vitro and in vivo. These include brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF), insulin-like growth factor (IGF) and vascular endothelial growth factor (VEGF). One of the promising ways of the delivery of supporting neuron survival factors is considered to be transplantation of genetically modified cells overexpressing recombinant therapeutic genes. This article describes generation of cellular delivery vectors of therapeutic genes - human umbilical cord blood mononuclear cells genetically modified by dual cassette plasmids, expressing two therapeutic genes. Efficiency of transgene expression was confirmed in vitro using RT-PCR. Analysis of survival, migration, and phenotype of genetically modified cells was performed 2 weeks after transplantation into transgenic mice with amyotrophic lateral sclerosis phenotype

Improved method for the obtaining DTTA-appended 2,2’-bipyridine ligands for lanthanide cations

The composition of the reaction mixture after DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines was studied. In addition to the target product, DTTA-appended 2,2’-bipyridine, the corresponding 6'-hydroxymethyl-substituted 2,2’-bipyridine and (5'-phenyl-[2,2'-bipyridin]-6-yl)methyl formate were isolated as by-products in some cases. Finally, an improved procedure for the DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines by using Finkelstein reaction was developed

Development of ELISA test for the quality control of Pseudomonas aeruginosa recombinant vaccine based on the hybrid recombinant protein

A hybrid recombinant protein containing the amino  acid sequences of the three  most significant Pseudomonas aeruginosa antigens  (membrane proteins OprF, OprI  and toxoid  aTox)  was incorporated into a vaccine against Pseudomonas infection. Quality control of a hybrid recombinant protein and appropriate vaccine includes  determination of authentity and completeness of adsorption upon aluminum hydroxide adjuvant. The aim of our study was to develop  techniques of quality  control for a vaccine  based on the hybrid  OprF-aToxOprI  recombinant protein specific  to  P. aeruginosa.  Hybridomas secreting  specific  monoclonal antibodies for OprF-aTox-OprI were derived  from the fusion of myeloma cells and murine spleen  cells immunized with recombinant proteins P. aeruginosa. To  produce sufficient  quantities of antibodies, the  hybrid  cells were in vivo cultured in BALB/c mice.  Supernates and ascite liquids were chromatographically purified  with immune sorbent. Conjugation of antibodies with  horseradish peroxidase was carried  out  according to  P.K.Nakane. The  hybrid  OprF-aTox-OprI recombinant protein was detected by the  solid-phase ELISA, using a panel  of monoclonal antibodies and  conjugates of monoclonal antibodies with  horseradish peroxidase. Monoclonal antibodies were specific for different  OprF-aTox-OprI epitopes. Titration assays containing OprF-aTox-OprI protein at 78 ng/ml to 5000 ng/ml were used as quantitative standards for calibration curves.To identify  the recombinant protein OprF-aTox-OprI, 55 variants  of of MAb pairs were tested.  Limits  of quantitative detection served  for selection of most  sensitive  and  specific  ELISA  variants.  The  quantitative detection limit was calculated for all 11 ELISA  variants.  Two ELISA  variants  with the highest  sensitivity were selected  for  quality  control of the  hybrid  recombinant protein. The  limits  of quantitative detection were, respectively, 2.9 and 13.6 ng/ml (0.0058  and 0.027% of the estimated antigen  content in the vaccine)  for the first and  second  ELISA  variants.  The  first variant  included a pair  of monoclonal antibodies specific  for the OprF  and OprI  epitopes, the second  variant  represented aTox and OprI  epitopes. Two variants  of ELISA  were developed to detect  the hybrid recombinant OprF-aTox-OprI protein. The first variant allows to determine the protein amount and to evaluate completeness of its adsorption on aluminum hydroxide. To confirm authenticity of the protein, both methods must be used, since they can detect all three antigens (OprF, aTox and OprI) which are present  in the fusion protein

Оценка эффективности оперативного лечения больных с хронической критической ишемией нижних конечностей в стадии трофических осложнений

Relevance. Chronic critical ischemia of the lower extremities (CCILE) in the stage of trophic complications is the final stage of diseases of the arteries of the lower extremities, leading to disability of patients and having a poor prognosis in terms of preservation of the lower extremities and mortality.Aim of study. Objective assessment of the efficacy of lower limb revascularization in trophic disorders.Material and methods. The analysis of treatment of 52 patients with stage IV CCILE (according to the classification of R. Fontaine and A.V. Pokrovsky) was carried out. Of these, 42 patients underwent three-phase scintigraphy combined with X-ray computed angiography on a hybrid apparatus. After the operation, this study was conducted in 37 patients.Results. Out of 52 patients, surgery for revascularization of the lower extremities was performed in 37 patients, 15 were not operated on. Out of 37 operated patients, improvement of blood circulation occurred in 32 (86.5%). Circulatory decompensation was observed in 5 patients (9.7%). Among non-operated patients, improvement of blood circulation occurred in 9 patients (17.3%), no effect or decompensation — in 5 (9.7%). Subjective improvement in the condition and decrease in the degree of ischemia corresponded to the improvement of microcirculation according to the data of three-phase scintigraphy.Conclusion.1. Revascularization of the lower extremities in patients with trophic disorders is an effective method of treating this pathology. Therefore, all patients with chronic ischemia threatening limb loss should be considered as candidates for revascularization.2. If the leg arteries or short occlusive or stenotic lesions of the main arteries are affected, such patients should be discussed together with specialists in endovascular surgery for endovascular treatment or joint intervention.3. Hybrid radiation method (three-phase scintigraphy and single-photon emission computed tomography, combined with X-ray computed angiography) is an objective method that reflects the state of peripheral circulation and microcirculation, and allows you to objectively assess the effectiveness of the treatment.Актуальность. Хроническая критическая ишемия нижних конечностей (ХКИНК) в стадии трофических осложнений представляет собой конечную стадию заболеваний артерий нижних конечностей, приводящую к инвалидизации больных и имеющую неблагоприятный прогноз по показателям сохранения нижних конечностей и летальности.Цель исследования. Объективная оценка эффективности реваскуляризации нижних конечностей при трофических расстройствах.Материал и методы. Проведен анализ лечения 52 больных ХКИНК IV стадии (по классификации R. Fontaine и А.В. Покровского). Из них 42 пациентам выполнена трехфазная сцинтиграфия, совмещенная с рентгеновской компьютерной ангиографией на гибридном аппарате. После операции данное исследование проведено 37 пациентам.Результаты. Из 52 пациентов операция по реваскуляризации нижних конечностей выполнена 37 пациентам, не оперированы 15. Из 37 оперированных улучшение кровообращения произошло у 32 (86,5%). Декомпенсация кровообращения отмечена у 5 пациентов (9,7%). Среди неоперированных пациентов улучшение кровообращения произошло у 9 пациентов (17,3%), отсутствие эффекта или декомпенсация — у 5 (9,7%). Субъективное улучшение состояния и снижение степени ишемии соответствовали улучшению микроциркуляции по данным трехфазной сцинтиграфии.Выводы.1. Реваскуляризация нижних конечностей у пациентов с трофическими нарушениями является эффективным методом лечения данной патологии. Поэтому все пациенты с хронической ишемией, угрожающей потерей конечности, должны быть рассмотрены как кандидаты для реваскуляризации.2. При поражении артерий голени или коротких окклюдирующих или стенотических поражениях магистральных артерий такие пациенты должны быть обсуждены совместно со специалистами по рентгенэндоваскулярной хирургии на предмет эндоваскулярного лечения или выполнения вмешательства совместно.3. Гибридный лучевой метод (трехфазная сцинтиграфия и однофотонная эмиссионная компьютерная томография, совмещенная с рентгеновской компьютерной ангиографией) является объективным методом, отображающим состояние периферического кровообращения и микроциркуляции, и позволяет объективно оценить эффективность проведенного лечения

ASSESSMENT OF CEREBRAL PERFUSION IN PATIENTS WITH HEMODYNAMIC ISCHEMIC STROKE UNDERGOING RECONSTRUCTIVE BRACHIOCEPHALIC ARTERY INTERVENTIONS

The paper deals with the assessment of cerebral perfusion in patients in the acute period of acute cerebrovascular accident before and after revascularization surgery. It gives a clinical example of using contrast-free perfusion magnetic resonance imaging (MRI) in a patient with hemodynamic ischemic stroke. The use of this technique made it possible to determine indications for early carotid endarterectomy for the contralateral internal carotid artery and to evaluate positive postoperative changes in cerebral perfusion and the patient’s neurological status. The authors analyzed the current literature on this problem with a particular emphasis on the possibilities of using dynamic susceptibility contrast-enhanced and arterial spin-labeling contrast-free perfusion MRI in this category of patients. Carotid endarterectomy in the acute period of acute cerebrovascular accident can improve cerebral hemodynamics and the patient’s neurological status and prevent recurrent cerebral circulatory disorders. Indications for this surgery should be determined by taking into consideration the results of perfusion MRI techniques (single-photon computed tomography contrastenhanced and contrast-free perfusion MRI)