[Prevention and treatment of venous thromboembolic complications in orthopedic patients]. / Kompleksnaya profilaktika i lechenie venoznykh tromboembolicheskikh oslozhnenii u patsientov ortopedicheskogo profilya.

OBJECTIVE: To analyze the comprehensive program for prevention of thromboembolic complications in orthopedic patients. MATERIAL AND METHODS: We have analyzed thromboembolic complications in orthopedic patients after surgeries on large joints over the past 5 years (2018-2022). CONCLUSION: A comprehensive approach to prevention and treatment of thromboembolic complications including ultrasound, early surgical prevention of pulmonary embolism can significantly improve postoperative outcomes after joint replacement surgery. Vacuum aspiration retrograde thrombectomy is effective, feasible and safe for acute ilio-femoral venous thrombosis reducing hospital-stay (p=0.0124) and restoring vein patency. Widespread thromboembolic complications, especially for pulmonary embolism in 2022, are likely due to a new coronavirus infection and require careful screening of patients with risk factors with appropriate preventive antithrombotic therapy.

Histological Justification for the Need of Radiofrequency Ablation of Pulmonary Arteries in Patients with High-Grade Secondary Pulmonary Hypertension.

The aim of the study was to perform a histological assessment of the effectiveness of radiofrequency exposure for circular denervation of the pulmonary artery in patients with secondary high pulmonary hypertension. Materials and Methods: The study was carried out on the autopsy material derived from non-operated patients. Three groups were formed. The experimental group included the material (207 histological samples) from the patients with chronic high pulmonary hypertension arising on the background of mitral heart disease. The samples of this group were exposed to circular radiofrequency ablation. In the comparison group, we used autopsy material (24 samples) obtained from the patients with high pulmonary hypertension. The control group included material (35 samples) from the patients without pulmonary hypertension who died from causes not associated with cardiovascular diseases. The samples of the comparison and control groups were not exposed to radiofrequency.Visual evaluation of the damage to the vascular wall was performed after hematoxylin and eosin staining, according to Van Gieson. Damage to the nerve plexuses was evaluated after their impregnation by silver salts. To assess the degree of damage to the vascular wall on the stained sections, a scoring method of semi-quantitative analysis of the observed pathological processes (fibrinoid necrosis, metachromasia, karyorrhexis, karyolysis, fibrinoid and mucoid swelling, lipid presence) was used. Silver salt impregnation allowed visualizing damage to the reticular fibers, trunks and endings of peripheral nerve fibers. Results: The mean optical density of the ablation group was statistically significantly lower than in the comparison and control groups (p<0.001). The mean specific area of tissue dissociation was higher in the "marginal zones" of the ablated sections, under pronounced mechanical compression in these areas. The difference in the mean areas of the argentophilic samples of the ablation and comparison and control groups was expressed in a lower percentage of argentophilic fibrous structures (p<0.05). At the same time, the highest concentration of argentophilic structures was observed in the comparison group, which points to a bigger content of nerve fiber structures in the patients with high pulmonary hypertension. Conclusion: The results of the histological study demonstrated the feasibility of radiofrequency ablation of the pulmonary arteries in patients with high-grade secondary pulmonary hypertension. Radiofrequency denervation leads to the destruction of the sympathetic ganglia in the adventitial layer of the pulmonary arteries, which are responsible for the spasm of the precapillary bed of the pulmonary circulation, which promotes vasodilation, an increase in the vascular bed, and, as a result, a reduction in pulmonary hypertension.

[Effectiveness of the Cox Maze-IV Procedure in Cardiac Surgery Patients With Atrial Fibrillation].

Aim Analyzing a 5-year experience of surgical treatment of cardiosurgical patients with atrial fibrillation (AF).Material and methods The study analyzed results of surgical treatment with extracorporeal circulation in 132 patients with AF who underwent the Maze-IV procedure using a radiofrequency ablator with transmurality feedback from 2013 through 2018.Results Two fatal outcomes were observed in the study group. These outcomes took place in the early postoperative period and were associated with progressive acute heart failure in patients with repeated surgery for mitral valve restenosis. 61.2% of the patients had no AF. Recurrent AF was observed during the first three years after surgery in association with withdrawal of the antiarrhythmic medication, which confirmed a need for long-term antiarrhythmic therapy. Analysis of risk factors for AF relapse identified significant predictors, including left ventricular dilatation larger than 5.5 cm at baseline and more than two-year duration of a history of arrhythmias.Conclusion The Maze-IV procedure proved an effective and safe method of surgical treatment in AF patients with acquired heart defects and ischemic heart disease, which allowed maintaining sinus rhythm in 61.2% of patients for 5 years. Preventive amiodarone saturation reduced the risk of AF relapse by 24.2 % (p=0.038) and incidence of postoperative arrhythmic complications by 34.9 % (p=0.008) in cardiosurgical patients.

Solvothermal synthesis of Sm3+-doped Fe3O4 nanoparticles.

Magnetic iron oxide nanoparticles doped with samarium were prepared by solvothermal polyol method. An introduction of 2,2'-bipyridine during the synthesis reduces the particle diameter to about 9nm in average. The difference in physical and magnetic properties of the samples prepared with and without capping agent was outlined on the basis of complex characterization by a number of experimental techniques. The characteristics of resulted product make it suitable for biomedical applications, for instance, as a contrast agent for MRI.

Accumulation of cAMP in gamma-irradiated thymocytes and internucleosomal DNA fragmentation.

Ionizing radiation, glucocorticosteroids and chemical inducers of differentiation (CID) are cytotoxic to thymocytes, and induce internucleosomal DNA fragmentation. Tissue cAMP levels in thymi of irradiated mice were significantly elevated as early as 30 min post-irradiation. In contrast, cAMP content in the liver was not changed significantly up to 1 h post-irradiation, and then some decrease occurred. Irradiation of isolated thymocytes gave essentially the same results as after irradiation of animals, and the elevation in cAMP 30 min after the irradiation, DNA fragmentation and cell death were linearly related to the dose up to 2.5 Gy. The maximal induction of cAMP level occurs in the fractions of radiosensitive cortical thymocytes. In thymocytes all CID tested also induced the increase in cAMP level with concomitant DNA fragmentation. Unlike ionizing radiation, UVC light did not induce cAMP accumulation and DNA fragmentation in thymocytes. Treatment of UV-irradiated cells with But2 cAMP did not result in an increase in DNA fragmentation. Ionizing radiation induced DNA fragmentation and cell death can be prevented by adding the protein kinases inhibitor H-7. Theophylline was shown to reduce the cAMP response, DNA fragmentation and cell death in gamma-irradiated thymocytes, suggesting that the accumulation of cAMP may be partly related to adenosine receptor sites.

Clinical and physiological basis for a new method underlying rehabilitation of the damaged visual nerve function by direct electric stimulation.

A new method of rehabilitation of damaged visual nerves has been tested during clinical physiological investigations in 45 patients with pathological opticochiasmal brain tumor, inflammation and trauma. The essence of the new method was in implanting the electrode into the nerve when the patient was operated on for the pathological formation and in directly stimulating the nerves for 2 or 3 postoperational weeks. Effectiveness of electrical stimulation was increased by direct recording of the electroneurogram as well as by the results of ophthalmological observations. Considerable improvement of vision was observed in 75%, and in 25% of these cases the vision was found to actually normalize. Even in cases of total blindness, vision was partially rehabilitated in 8 of 10 cases. Direct electrophysiological investigation of the visual nerve potentials enabled us to objectively estimate their functional state, predict the probability of visual rehabilitation as well as increase the efficiency of therapy. Neurophysiological mechanisms of visual rehabilitation under the influence of electrical stimulation of the visual nerves are discussed.