Methodology for Conducting Post-Marketing Surveillance of Software as a Medical Device Based on Artificial Intelligence Technologies.

The aim of the study was to develop a methodology for conducting post-registration clinical monitoring of software as a medical device based on artificial intelligence technologies (SaMD-AI). Materials and Methods: The methodology of post-registration clinical monitoring is based on the requirements of regulatory legal acts issued by the Board of the Eurasian Economic Commission. To comply with these requirements, the monitoring involves submission of the review of adverse events reports, the review of developers' routine reports on the safety and efficiency of SaMD-AI, and the assessment of the system for collecting and analyzing developers' post-registration data on the safety and efficiency of medical devices. The methodology was developed with regard to the recommendations of the International Medical Device Regulators Forum and the documents issued by the Food and Drug Administration (USA). Field-testing of this methodology was carried out using SaMD-AI designed for diagnostic imaging. Results: The post-registration monitoring of SaMD-AI consists of three key stages: collecting user feedback, technical monitoring and clinical validation. Technical monitoring involves routine evaluation of SaMD-AI output data quality to detect and remove flaws in a timely manner, and to secure the product stability. Major outcomes include an ordered list of technical flaws in SaMD-AI and their classification using evidence from diagnostic imaging studies. The application of this methodology resulted in a gradual reduction in the number of studies with flaws due to timely improvements in artificial intelligence algorithms: the number of flaws decreased to 5% in various aspects during subsequent testing. Clinical validation confirmed that SaMD-AI is capable of producing clinically meaningful outputs related to its intended use within the functionality determined by the developer. The testing procedure and the baseline testing framework were established during the field testing. Conclusion: The developed methodology will ensure the safety and efficiency of SaMD-AI taking into account its specifics as intangible medical devices. The methodology presented in this paper can be used by SaMD-AI developers to plan and carry out the post-registration clinical monitoring.

Removal of the Tumor Thrombus from the Right Atrium without Extracorporeal Circulation: Emphasis on the Displacement of the Tumor Apex.

OBJECTIVES: To assess the outcomes of cavoatrial tumor thrombus removal using the liver transplantation technique for thrombectomy, a retrospective study was conducted. MATERIALS AND METHODS: Five patients with atrial tumor thrombi who underwent piggy-back mobilization of the liver, surgical access to the right atrium from the abdominal cavity, and external manual repositioning of the thrombus apex below the diaphragm (milking maneuver) were included into the study. Extracorporeal circulation was used in none of the cases. The average length of the atrial component of the tumor was 20.0 ± 11.7 mm (10 to 35 mm), and the width was 14.8 ± 8.5 mm (10 to 30 mm). In this work, the features of patients and surgical interventions as well as perioperative complications and mortality were analyzed. RESULTS: External manual repositioning of the tumor thrombus apex below the diaphragm was successfully performed in all patients. Tumor thrombi with the length of the atrial part up to 1.5 cm were removed through the extrapericardial approach. For evacuation of the thrombi with the large atrial part (3.0 cm or more), a transpericardial surgical approach was required. Specific complications associated with the access to the right atrium from the abdominal cavity (paresis of the right phrenic nerve, pneumothorax, and mediastinitis) were not detected in any case. The average clamping time of the supradiaphragmatic inferior vena cava (IVC) was 6.3 ± 4.6 min. The volume of intraoperative blood loss varied from 2500 to 5600 ml (an average of 3675 ± 1398.5 ml). CONCLUSION: Our work represents the initial experience in the liver transplantation technique for thrombectomy in distinct and well-selected patients with atrial tumor thrombi. The effectiveness of this approach needs further study. The video presentation of our research took place in March 2019 at the 34th Annual EAU Congress in Barcelona.

α2-Adrenoceptor signaling in cardiomyocytes of spontaneously hypertensive rats starts to impair already at early age.

α2-Adrenoceptors (α2-AR) found in the cardiomyocyte's sarcolemma represent a very important negative feedback for control of myocardial contractility by endogenous catecholamines. Earlier, we showed that the endogenous neurotransmitter agmatine in micromolar concentrations via α2-AR activates the nitric oxide (NO) synthesis, enhancing the Ca2+ pumping into sarcoplasmic reticulum (SR). In the millimolar doses it inhibits Ca2+ sequestration by SR Ca2+ ATPase (SERCA), acting through the first type of imidazoline receptors. Here, we study the functional activity of agmatine, as well as a specific α2-agonist, guanabenz, in respect to spontaneous Ca2+-transients in SHR cardiomyocytes of the early age (2-2.5 months), and adulthood animals (8-9 months). α2-mediated cardioprotective effect was almost twofold decreased in SHR cardiac cells compared to normotensive rats of the corresponding age, despite the fact that both α2A- and α2B-AR protein levels were significantly increased in SHR cardiomyocytes. NO-mediated facilitation of SERCA activity is substantially reduced in SHR cardiomyocytes vs. normotensive rats. These data suggest that the SHR phenotype starting from early age shows signs of the impaired sarcolemmal α2-AR signaling, which can aggravate the development of this cardiovascular pathology.

[Non-Central Influences of α2-Adrenergic and Imidazoline Agonist Interactions in Isolated ardiomyocytes Cardiac Cells].

AIM: to investigate the functional interaction of α2-adrenergic and imidazoline receptors recently identified on the sarcolemma of isolated cardiomyocytes for regulation of the intracellular calcium and the production of the signal molecule of nitric oxide (NO). MATERIALS AND METHODS: experiments were performed on isolated left ventricular cardiomyocytes of Wistar rats. Potential-dependent Ca2+-currents were measured from the whole-cell by the patch-clamp method in "perforated-patch" configuration. The intracellular calcium and the production of nitric oxide were estimated from the changes in fluorescence intensity of the Ca2+-specific and NO-sensitive dyes at fluorescent or confocal microscope. RESULTS: It has been shown that α2­adrenergic and imidazoline receptor agonists inhibit L-type Ca2+-currents by themselves, but their effects do not develop against each other's background. The blockade of key effector molecules: protein kinase B (Akt kinase) for α2­adrenergic receptors, and protein kinase C for imidazoline receptors causes the action of agonists to become additive. Both the selective α2­agonist, guanabenz, and the specific agonist of the first type imidazoline receptors, rilmenidine, show an additional inhibition of Ca2+-currents against the basal background already reduced by the activation of one of the two receptor systems. Wherein rilmenidine increases the level of free  Ca2+ in the cytosol, and guanabenz, on the contrary, decreases it. The action of guanabenz does not develop against the background of rilmenidine, although it, in turn, effectively increases the intracellular level of calcium in guanabenz-pretreated cardiac cells. Activation of α2­adrenergic receptors leads to significant stimulation of the endothelial isoform of NO-synthase, and as a result to an increase in the NO level. Activation of imidazoline receptors itself does not affect NO synthesis but it prevents the production of NO induced by α2­agonists. CONCLUSION: obtained data make it possible to formulate a number of useful recommendations for clinical practice, and also to clarify the non-central peripheral effects arising from the activation of α2­adrenergic or imidazoline systems under conditions of endogenous hyperactivation on of the two systems.

Synergism of myocardial ß-adrenoceptor blockade and I1-imidazoline receptor-driven signaling: Kinase-phosphatase switching.

Recently identified imidazoline receptors of the first type (I1Rs) on the cardiomyocyte's sarcolemma open a new field in calcium signaling research. In particular, it is interesting to investigate their functional interaction with other well-known systems, such as ß-adrenergic receptors. Here we investigated the effects of I1Rs activation on L-type voltage-gated Ca2+-currents under catecholaminergic stress induced by the application of ß-agonist, isoproterenol. Pharmacological agonist of I1Rs (I1-agonist), rilmenidine, and the putative endogenous I1-ligand, agmatine, have been shown to effectively reduce Ca2+-currents potentiated by isoproterenol. Inhibitory analysis shows that the ability to suppress voltage-gated Ca2+-currents by rilmenidine and agmatine is fully preserved in the presence of the protein kinase A blocker (PKA), which indicates a PKA-independent mechanism of their action. The blockade of NO synthase isoforms with 7NI does not affect the intrinsic effects of agmatine and rilmenidine, which suggests NO-independent signaling pathways triggered by I1Rs. A nonspecific serine/threonine protein phosphatase (STPP) inhibitor, calyculin A, abrogates effects of rilmenidine or agmatine on the isoproterenol-induced Ca2+-currents. Direct measurements of phosphatase activity in the myocardial tissues showed that activation of the I1Rs leads to stimulation of STPP, which could be responsible for the I1-agonist influences. Obtained data clarify peripheral effects that occur during activation of the I1Rs under endogenous catecholaminergic stress, and can be used in clinical practice for more precise control of heart contractility in some cardiovascular pathologies.

[The association of gamma-synuclein autoantibodies with the polymorphism in exon 4 of the coding gene]. / Sviaz' nalichiia autoantitel k gamma-sinukleinu s polimorfizmom v 4-m ékzone kodiruiushchego gena.

AIM: To analyze the polymorphism in exon 4 of the gamma-synuclein gene (SNCG) in patients with autoantibodies against the gamma-synuclein protein. MATERIAL AND METHODS: To identify autoantibodies against gamma-synuclein, the serum from patients with chronic cerebral ischemia and cervical osteochondrosis was used. All patients were women of the Slavic ethnic group, mean age 61±5 years. The isolated genomic DNA was used to determine the point mutation in exon 4 by the restriction endonuclease HphI and subsequent sequencing of the resulting fragments to confirm the results. RESULTS AND CONCLUSION: Antibodies against gamma-synuclein were identified in 2 patients with chronic cerebral ischemia and 3 with cervical osteochondrosis. All five patients had a T to A substitution at position 371, which was detected by the restriction endonuclease HphI resulting in a hydrolysis of the amplicon and the formation of two fragments. The subsequent sequencing of exon 4 of the SNCG revealed no other mutations and confirmed the T to A substitution. This single nucleotide polymorphism results in the amino acid substitution of glutamic acid to valine at position 110 (out of 127), changing its physicochemical properties and the ability to form aggregates as well as post-translational modifications. The obtained results provide grounds for further association studies of SNCG polymorphism in patients with various diseases of the nervous system.

[The FUS protein: Physiological functions and a role in amyotrophic lateral sclerosis].

Certain forms of amyotrophic lateral sclerosis (ALS) are associated with an altered compartmentalization of FUS and its aggregation in the cytoplasm of motoneurons. FUS is a DNA/RNA-binding protein that is involved in DNA repair and the regulation of transcription, splicing, RNA transport, and local translation. Two theories have been proposed to explain the mechanism of the pathophysiological process in ALS. The theories attribute degeneration of motor neurons to either loss or gain of FUS function. The review describes the main physiological functions of FUS and considers evidence for each of the theories of ALS pathogenesis.

[Dimebon delays the onset of symptoms of FUS-proteinopathy in transgenic mice]. / Otsrochennyi debiut simptomaticheskoi stadii FUS-proteinopatii u transgennykh myshei pod deistviem dimebona.

AIM: To evaluate an effect of dimebon on the onset of symptomatic stage in FUS.1-513 transgenic mice - a new genetic model of neurodegeneration, and to study the dynamics of disease progression in the terminal stage. MATERIAL AND METHODS: The study was carried out on males of line FUS1-513 with the contribution of genes from CD1 strains. Mice of the experimental group (n=28) received dimebon with water in the concentration of 70 mcg/ml starting from the 35th day of life. The control group (n=25) did not receive the drug. Age, body mass of animals at the start of symptomatic stage and duration of symptomatic stage were assessed. RESULTS: Application of dimebon can delay the onset of the manifestation of clinical symptoms of the neurodegenerative process in the experimental group (127.6±4.6 days) compared to the control group (110.6±4.2 days). The body mass was similar in both groups. CONCLUSION: Dimebon leads to an increase in the duration of presymptomatic stage and delays the manifestation of clinical symptoms. The changes in the dynamics of the pathological process in the symptomatic stage are not detected.

Detection of autoantibodies to potentially amyloidogenic protein, gamma-synuclein, in the serum of patients with amyotrophic lateral sclerosis and cerebral circulatory disorders.

In this study, we analyzed serum for the presence of antibodies to gamma-synuclein in patients with amyotrophic lateral sclerosis (ALS) compared to the control group of patients with other neurological diseases and healthy control donors. As a result, antibodies against gamma-synuclein are not an ALS-specific feature and have been identified in patients with ALS as well as in the control group patients. Patients with the impaired cerebral circulation showed increased incidence of autoantibodies to gamma-synuclein, yet the difference lacks statistical representativeness due to limited sample size.

[STANDARD TRANSCUTANEOUS AND ULTRA-MINI TRANSCUTANEOUS NEPHROLITHOTRIPSY IN TREATMENT OF NEPHROLITHIASIS].

Comparative analysis of two variants of transcutaneous nephrolithotripsy (TCNLT) in 45 patients, suffering nephrolithiasis, was performed. In 17 patients (the first group) the ultra-mini (UM) TCNLT, using tubus 11Сh, was done, and in 28 patients (the second group) ­ TCNLT, using a standard tubus 24Сh. The operation duration in the first group have had constituted (86.2 ± 16.3) min at average, and in the second group ­ (51 ± 13.6) min. The method of UМ TCNLT is a secure, miniinvasive, owing low rate of morbidity, comparing with a standard procedure, but with equal efficacy, concerning the «stone free¼ status (accordingly, 95.3 and 96.5%) in patients when calculi's diameter up to 2 sm. Тubus 11Ch guarantees lesser risk of hemorrhagic complications occurrence, permits to conduct UM TCNLT without nephrostomic draining of the renal calyx and pelvis system more confidently.

[ОPTIMIZATION OF EXAMINATION ALGORITHM FOR PATIENTS BEFORE AND AFTER OPERATIVE INTERVENTION FOR HYDRONEPHROSIS].

Algorithm of the patients examination, suffering hydronephrosis, caused by obstruction of different etiology, was optimized, what permitted, using qualification of rational volume and sequence of diagnostic methods, owing high sensitivity and specificity, as well as morphological diagnostic coefficients (parenchymal­stromal, dysbalance of collagens) and the risk criterion for recurrence occurrence, to estimate renal structure­ functional state, to determine the disease stage, its course severity and to substantiate a volume and duration of preoperative preparation needed, the operative intervention kind and postoperative management of the patients.

[COMPLICATIONS OF SURGICAL TREATMENT OF A RENAL­CELL CANCER WITH INTRAVENOUS SPREADING].

Retrospective investigation, conducted for estimation of perioperative complications, while performing surgical treatment of a renal­cell cancer with tumoral thrombi, was presented. In 132 patients the tumoral thrombi spreading is restricted by renal vein and by vena cava inferior (VCI) as well. The patients were operated on, using the "chevron" access in the absence of artificial blood circulation. Perioperative complications rate in the patients in presence of macroscopic tumoral thrombi constitute 56.8%, while tumoral spreading into VCI ­ is trustworthy bigger (р<0.05). Presence of cardiac insufficiency, tumoral invasion of the VCI wall, retrograde spreading of thrombus with the VCI concurrent blood thrombosis, аs well as presence of the indices in accordance to the ECOG scale more than 1 point have constituted unfavorable factors.

[Cytokines neuroinflammatory reaction to the action of homoaggregatic and liposomal forms of b-amyloid 1-40 in rats].

An injection model of preclinical stages of Alzheimer's disease has been reproduced in rats. It was accompanied by the decrease in the latent period of conditioned reflex avoidance, increasing levels of endogenous b-amyloid peptide 1-40 and activation of inflammatory cytokines (IL-1b, TNF-a, IL-6, IL-10) in the cerebral cortex, hippocampus and blood serum of experimental animals. We belive that changes identified at the biochemical level are prerequisite to modulate neuronal functions in rats induced by Ab40_Human administration. The toxic effect of exogenous b-amyloid 1-40 homoaggregates caused intense response of the cytokine system, while its liposomal form caused the soft information signal to the activation of innate immunity.

The role of ß-amyloid peptide in neurodegenerative diseases.

Studies of neurodegenerative disorders (NDDs) are drawing more attention of researchers worldwide due to the high incidence of Alzheimer's disease (AD). The pathophysiology of such disorders is, in part, characterized by the transition of a wild-type peptide from its native conformation into a very stable pathological isoform. Subsequently, these abnormal proteins form aggregates of amyloid fibrils that continuously increase in size. Changes in the metabolic processes of neurons (e.g. oxidative stress, hyperphosphorylation of the tau protein, and resulting secondary changes in the cell metabolism) ultimately lead to cell death. We hypothesize that extracellular deposition of ß-amyloid peptide fibrils and neurofibrillary tangles represents the body's adaptation mechanism, aimed at preservation of autonomic functioning; while the cognitive decline is severe, the rest of the organ systems remain unaffected and continue to function. This hypothesis is supported by the fact that destruction of pathological plaques, fibrils, and tangles and the use of vaccines targeting ß-amyloid result in undesirable side effects. To gain a better understanding of the pathophysiology of Alzheimer's disease and to develop novel therapies, continued studies of the sporadic form of disease and the mechanisms triggering conformational changes in ß-amyloid peptide fragments are essential. This review is focused on studies investigating the formation of amyloid fibrils and their role in the pathogenesis of neurodegenerative diseases. In addition, we discuss a related disorder--amyloidosis--where formation of fibrils, tangles, and plaques leads to neuronal death which may occur as a result of a failed adaptation process. Further in-depth investigation and comprehensive analysis of alterations in the metabolism of APP, ß-amyloid, and tau protein, which have a pathological effect on cell membrane, alter phosphate exchange, and impair other key metabolic functions of the cell long before the characteristic amyloid deposition takes place, is warranted. A better understanding of intraneuronal processes is crucial in identifying specific inhibitors of pathologic neuronal processes and, consequently, will allow for targeted therapy, thus maximizing efficacy of selected therapeutic regimens.

The role of lipids in the interaction of Acholeplasma laidlawii cells with lymphocytes.

The role of A. laidlawii membrane lipids in the organism's interaction with mouse spleen lymphocytes is analyzed. A. laidlawii cells were grown in a lipid-poor medium with unsaturated fatty acids that allowed cells with different degrees of membrane lipid microviscosity to be obtained. The intensity of the binding of A. laidlawii cells and derived liposomes with lymphocytes depended directly on the degree of fatty acid unsaturation. Cholesterol incorporation into the A. laidlawii membrane reduced the fluidity of the lipid bilayer and decrease the binding activity. The intensity of cholesterol transfer from lymphocytes to A. laidlawii also depended on the degree of fatty acid unsaturation in A. laidlawii cells. Cells enriched with cholesterol took up considerably less of this sterol from lymphocytes. The loss of cholesterol as well as the enrichment of lymphocytes by A. laidlawii membrane fatty acids resulted in a decrease in the microviscosity of lymphocyte membrane lipids. It was concluded that the ability of A. laidlawii cells or derived liposomes to stimulate the transport of carbohydrates into lymphocytes depended on the degree of unsaturation of fatty acid incorporated into A. laidlawii. Cholesterol also decreased the stimulatory effect, probably by lowering carbohydrate carrier mobility.

Obtaining and diagnostic use of immunospecific serum to protein of human decidual tissue.

A method of diagnosis of early periods of pregnancy has been developed. Immunospecific serum to human decidual tissue protein D1 was used. The technique is relatively simple, easily reproducible and can be used for a differential gynecologic diagnosis as well as for a diagnosis of pregnancy.

Changes of the uterus epithelium proteins during the menstrual cycle and early pregnancy.

The changes in soluble cell proteins during stepped differentiation (from proliferative stage to secretory stage) of human uterus epithelium were studied. Polyacrylamide gel electrophoresis revealed 21 fractions of soluble endometrial proteins in the proliferative stage and 20 fractions in the secretory stage. During the first 12 weeks of pregnancy soluble decidual proteins consist of 13 fractions. In the process of stepped differentiation of the uterus epithelium a specific fraction that was absent in the original tissue was observed. Moreover two specific fractions, D1 (light) and D2 (heavy), were detected in soluble proteins of decidual tissue. According to data from SDS electrophoresis these two fractions had molecular weights of 52,000 and 150,000, respectively. A decrease in soluble protein fractions during stepped differentiation of human uterus epithelium seems to be connected with increased specialization of this tissue.