Publications by authors named "Tsapenko I"

The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.

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Under virtual labor migration, or telemigration, in the expert community it is customary to understand remote work or the provision of services that are carried out in a cross-border format. The presence of the word in this term logically prompts us to consider the designated process in a migration context. From the standpoint of the concept of migration transition, the spread of virtual migration can be interpreted as a new link in the chain of mobility transformations generated by multifaceted digital transformations.

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Forced mobility and forced immobility are not just polar types of involuntary migration behavior. According to the author, they are closely interconnected and are like communicating vessels, being a product of common causes: conflict, violence, and unfavorable environmental processes, the action of which can be both stimulating and hindering movement. The decision to leave or stay is influenced by a wide range of objective factors and subjective circumstances, including values, preferences, emotions, irrationality, etc.

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Unlabelled: Various animal models of atrophy of retinal pigment epithelium (RPE) are created in order to study certain aspects of geographical atrophy in humans. To study the effects of new methods of therapy, it is necessary to determine the objective functional markers of structural changes in the retina.

Purpose: To determine the alterations in activity of the retina that characterize its remodeling in induction of RPE atrophy.

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Unlabelled: The clinical sugnificance of electroretinogram interpretation depends heavily on the employed mathematical apparatus. Currently, conventional calculation of the amplitude and time parameters of electroretinogram (ERG) components and their relations (indices), as well as analysis of the frequency spectrum of the signal are becoming insufficient for interpretation of the obtained data. New approaches to diagnostics are currently being developed, using, among other things, expert systems, and neural network and simulation models.

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The review discusses literature data on the clinical relevance of functional assessment of magno- (M), parvo- (P), and koniocellular (K) pathways. It also covers the differential contribution of the M, P, and K channels to visual impairments and how it determines the prognosis, early diagnosis, and treatment choice in patients with neurodegenerative diseases of the retina and brain. Selective changes in the performance of the visual channels are investigated by the example of glaucoma and optic neuritis in multiple sclerosis (MS) patients.

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In this paper, technical details of visual evoked potentials (VEP) assessment and pattern electroretinography (PERG) are reviewed. Both methods are used to perform an objective functional examination of visual channels and to clarify the level, at which they have been damaged. Contributions of parvo- (P), magno- (M) and koniocellular (K) systems to the morphology of PERG and VEP responses are discussed with account to test conditions, selectively supportive of the activity of particular cell populations.

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Unlabelled: Early diagnosis of primary open-angle glaucoma (POAG) is closely connected with detection of normal age-related changes in the retina. It is also essential to develop reliable methods for quantitative evaluation of retinal nerve fiber layer (RNFL) thickness and retinal ganglion cells (RGCs) structure and function as well as to extend opportunities for inter-instrumental comparisons.

Aim: to assess the function of RGCs from parvo- and magnocellular pathways by means of pattern electroretinography and to evaluate the degree of retinal sensitivity loss and RNFL thickness using new methods of analysis in normal aging and the early stage of POAG.

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This review provides an outline of circadian disorders associated with neurodegenerative diseases of the brain in the elderly, including Alzheimer's (AD) and Parkinson's diseases (PD). Since light is one of the most powerful environmental cues synchronizing physiological rhythms, exposure to bright light is often used to treat sleep disorders, behavior of patients with severe dementia, gait, and other functions disordered in CNS pathologies. Photobiomodulation effects of the low-energy laser and LED radiation is also considered as a potential tool for the rehabilitation of patients with various pathologies.

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Electrophysiological examinations (in accordance with the ISCEV Standards and original protocols) were performed after neoadjuvant chemotherapy or before and after superselective intra-arterial chemotherapy (SIACT) in 18 children aged 1-3 years with either newly diagnosed advanced retinoblastoma (8 eyes) or resistant retinoblastoma (14 eyes). The most considerable decrease in amplitude was demonstrated by the cone response b-wave, photopic 24 Hz flicker electroretinogram (ERG), photopic negative response, and the P1-component of multifocal ERG, indicating a significant dysfunction of bipolar and ganglion cells, more pronounced in the macular zone. After the SIACT, central retinal functions improved.

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Flicker-ERG (FERG) amplitude and glial indices Cg were measured to estimate angiotensin- converting enzyme (ACE) inhibitor Perindopril effect on retinal glial-neuronal interactions in patients with type II diabetes and diabetic retinopathy (DR). Intake of 5 mg Perindopril daily during 2 months improved photoreceptor and bipolar cells function in all stages of DR with the most significant effect in preproliferative DR (PPDR). After treatment course initially supernormal FERG scotopic glial indices reduced by 8,3-12 Hz (25-33%) in nonproliferative DR and PPDR and by 10% in proliferative DR.

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The possibility and the mechanism of the reduction of nitrites in retinal vessels under the acute hypoxia in vivo have been investigated. An experimental model of the rat retina ischemia was elaborated using the laser coagulation of retinal vessels. It was demonstrated that the vessel thrombosis does not occur if the nitrite concentration in the vessels is increased.

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Electroretinography is an informative tool in evaluating retinal function in age-related macular degeneration (ARMD) and in monitoring the treatment of choroidal neovascularization (CNV). The review gives the results of electroretinographic studies in the monitoring of CNV, by using photodynamic therapy (PDT) and angiostatic agents and in combined PDT and anti-VEGF therapy. The regularities of retinal functional changes in the early and late periods after mono- and combined therapy are considered.

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The pathophysiological mechanisms responsible for the development of choroidal neovascularization (CNV) in age-related macular degeneration (ARMD) still remain to be little studied and clinical electrophysiology that has a wide spectrum of objective studies plays a great role in the assessment of regularities of retinal functional changes in this disease. Recording of different types of electroretinograms (ERG) from the ISCEV standards and multifocal ERG is most extensively used to characterize CNV. The review considers the pattern of ERG changes in normal physiological aging and the specific features of suppressed retinal electrogenesis in neovascular ARMD.

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The investigation studied the topographic features of retinal electrogenesis in regmatogenic retinal detachment (RRD) in the myopic eye, by using multifocal electroretinography (mfERG). Both eyes from 12 patients were used to analyze the amplitude and latency of the first negative and positive mfERG first-order kernel components averaged over the entire stimulation area, by rings, quadrants of vision fields and in the areas of the adjacent and detached retina. The myopic eye in RRD even without macular involvement showed a selective reduction in R1 amplitude when central retinal rings 1 and 2 were stimulated, which suggests that the macular region is highly sensitive to the impaired anatomic integrity of the adjoining retinal zones.

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Mitochondria-targeted cationic plastoquinone derivative SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) has been investigated as a potential tool for treating a number of ROS-related ocular diseases. In OXYS rats suffering from a ROS-induced progeria, very small amounts of SkQ1 (50 nmol/kg per day) added to food were found to prevent development of age-induced cataract and retinopathies of the eye, lipid peroxidation and protein carbonylation in skeletal muscles, as well as a decrease in bone mineralization. Instillation of drops of 250 nM SkQ1 reversed cataract and retinopathies in 3-12-month-old (but not in 24-month-old) OXYS rats.

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We studied the development of retinal ischemia in rat eye after laser coagulation of blood vessels. Typical signs of ischemia manifested in the retina after 24 h: development of stable retinal edema, decrease in the b/a index (ratio of the electroretinogram b and a-wave amplitudes) to 1-2 units, pronounced disorders in the retinal microcirculation system, leading to ischemia of the inner layers of the retina. The proposed model is convenient for studies of the development of acute retinal ischemia, is easily realized, and reproduces some acute ischemic diseases of the retina.

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A new procedure is proposed for the experimental simulation of retinal ischemia, which develops the latter of the preset area and depth. The clinical and morphofunctional characteristics of retinal ischemia are given. Simulation of retinal ischemia via the photocoagulation effect of argon laser on the rabbit great retinal vessels demonstrated an inflammatory reaction, followed by occlusion and the development of ischemia in the blood-supplied retinal layers, vascular endothelial damage at the site of laser coagulation.

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Among the potential sources of cells for transplantation, the most promising autologous material for cell therapy and tissue engineering are multipotent mesenchymal stem cells (MMSC). The authors carried out an experiment dealing with MMSC xenotransplantation into the rabbit suprachoidal space on a model of laser retinal coagulation. For objective assessment of the magnitude and pattern of changes in the functional activity of different retinal cellular elements and the efficiency of MMSC transplantation, they performed electroretinographic and histological studies.

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The impact of ozone therapy on changes in the data of maximum combined electroretinography (ERG), macular ERG (MERG), and rhythmic ERG (RERG) at 12, 32, and 40 Hz was studied in the rehabilitative period in patients operated on for rhegmatogenous retinal detachment. The integral and local glial indices K(g) and K(c) were calculated. Studies were conducted before, within 1 week and 1 and 2 months after a course of therapy.

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The pattern of functional impairments and the antioxidative and antiproteolytic status of tear were studied, by experimentally simulating retinal ischemia in rabbits and during treatment with Selecarten. Simulated retinal ischemia resulted in the development of persistent (up to 3 weeks) retinal electrogenetic disorder. Selecarten instillations produced a moderate neuroprotective effect, by positively affecting retinal function early after ischemia stimulation and accelerated the recovery of retinal electrogenesis late after laser coagulation of retinal vessels.

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Macular drusen are known to be a major risk factor of age-related macular degeneration (ARMD) of the retina. The use of laser coagulation of macular drusen to prevent the progression of a dystrophic process remains to be disputable question so far. This paper presents the clinical and functional results of laser coagulation of macular drusen in 30 patients with bilateral retinal ARMD.

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