A novel approach to initial hearing assessment

Objective: justifying the possibility of using frequency-based hearing research via the web application ‘Automated System for Initial Hearing Assessment’. Materials and methods. The study was carried out at the Department of Otorhinolaryngology of the Samara State Medical University clinics in October 2019. It involved 91 patients 17 to 73 years old (average age 48±14.6 years). All study participants were divided into two age groups: Group I 17-59 years old), and Group II (over 60 years old). Patients were required to undergo two hearing assessment tests: using the Interacoustics AC-40 clinical audiometer and using our web application ‘Automated System for Initial Hearing Assessment’ (patent No. 2019664671). Results. The maximum difference in average hearing thresholds between pure-tone threshold audiometry and the web application in Group I was 3.3 dB at a frequency of 2 kHz on the right and 3.2 dB at frequencies of 2 and 4 kHz on the left; in Group II, it constituted 4.7 and 3.5 dB at 1 and 2 kHz, on the right, correspondingly, and 7.2 dB at 4 kHz on the left. The presented data were evaluated using the Cohen’s kappa coefficient, which confirmed high level of agreement between the results obtained using the clinical audiometer vs. our original web application. Conclusion. Based on the obtained results, a conclusion was made about the possibility of using the original web application for the initial hearing express assessment in general practice in conditions of limited availability of audiological care.

Cerebroprotective effect of xantohumol sensu experimental stroke model: study design and preliminary results

The objective of our study was to evaluate the cerebroprotective effect of xanthohumol (ХN) on experimental models of acute ischemic stroke in vivo and in vitro. Materials and methods. We used middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD) as in vivo and in vitro models. Our study subjects were Sprague-Dawley rats, which were randomly assigned to three groups: the control group and two MCAO groups with and without XN. The primary culture of cortical neurons was obtained from newborn rats. We employed the Bederson test and the corner test to evaluate neurological disorders. Results. The preliminary results indicated a possible cerebroprotective effect of XN in an ischemic stroke model. Conclusion. Preventive administration of XN before cerebral ischemia in an experiment can effectively reduce the volume of cerebral infarction and improve neurologic deficit 24 hours after MCAO.

Traumatology institutions in the early years of the soviet state: a gap in the history of Russian traumatology and orthopedics

Background. The formation and development of industrial model for social processes and systems in the early twentieth century brought to life a novel form of organizing scientific activity via establishing research institutions. Objective. This study aimed to investigate the gaps in the history of traumatology institutions in the early years of the Soviet State. Materials and methods. We carried out a comprehensive analysis to retrieve the data from both State and institutional archives, as well as from the literature sources. The narrative analysis was chosen as the method of data interpretation. Most archive documents are made available to the scientific community for the first time. Our study covered the period of time from 1917 to 1930. Over 500 sources were analyzed. Results. We established that the first five traumatology institutions were founded in the following sequence: Saratov Traumatology Institute in 1919, Rostov Traumatology Institute in 1920; Astrakhan, Moscow Oblast, and Voronezh Traumatology Institutes in 1921. The concept of research institution was mainly designed to achieve the systematic augmentation of scientific knowledge and form a new employee type called a professional scientist. Conclusion. Discovering the history of establishing first traumatology institutions that provided healthcare services and conducted independent scientific studies led us to defining a new, previously unexplored institutionalization stage of Russian traumatology and orthopedics. In the early years of the Soviet State, research institutions facilitated the development and implementation of efficient medical technologies into healthcare practice.

Stress-strain properties of aponeurotic suture in anterior abdominal wall after a midline laparotomy

Objective: method development for preventing postoperative ventral hernias based on experimental assessment of the stress-strain properties of aponeurosis in various types of a midline laparotomy. Materials and methods. We evaluated 42 fascia muscular aponeurotic complexes of the anterior abdominal wall. Based on the technique for dissecting the aponeurosis and its suturing, the complexes were divided into two groups (each containing 21 samples): Group 1 with a bypass of the umbilical ring on the left, and Group 2 with umbilical ring dissection. Results. Fascia aponeurotic complexes dissected and sutured through the umbilical ring (Group 2) had, on the average, higher values of mechanical characteristics. E.g., mean values of tensile stress (S), tensile stress at a maximum load (Smax), Young’s modulus (E), aponeurotic tensile strain (D), aponeurotic tensile strain at a maximum load (Dmax), and maximum load level (Load) were higher in Group 2 by 35.4; 39.8; 14.9; 34.6; 30.2 and 40.2 (%), respectively. Conclusion. We conducted the development, experimental application and evaluation of a novel method for preventing postoperative ventral hernias after a midline laparotomy based on the assessment of the stress-strain properties of aponeurosis.

Morphological aspects of orbital defect reconstruction in rats with elastin-based biomaterial

The objective of the study was to identify morphological aspects of replacement of xenogeneic decellularized elastin matrix (ХDEM) transplanted into a bone defect of the upper orbital wall in rats. Materials and methods. The experiment was performed on 60 Wistar rats with artificially created 7×4 mm defect in the upper edge of their orbit. In the experimental group (n=30), DХEM was placed in the defect area. Its size matched the size of the defect, and it was attached with a suture material (50 μm silk). Soft tissues were sutured layer by layer in the control group (n=30). Tissue excision was performed after 1, 3 and 12 months. Histological, immunohistochemical and electron microscopic methods were employed. Results. We were gradually replacing DХEM with bone tissue against the background of a pronounced reaction of CD68+/MMP-9+ macrophages, which implied its resorption and lysis. Osteogenesis occurred via intramembranous ossification and endochondral ossification, which was preceded by centripetal migration of endothelial kidneys with subsequent differentiation into capillaries and overgrowth of loose fibrous connective tissue containing progenitor cells. The microenvironment, represented by reticulin fibers, TGF-β1, and sulfated glycosaminoglycans, could contribute to the differentiation of progenitor cells in the osteogenic direction and to osteogenesis per se. In the control group, the defect remained open throughout the experiment. Conclusion. Decellularized biomaterial, based on elastin matrix, has osteoconductive and osteoinductive properties and can serve an adequate biomimetic for reconstruction of the bone defects.

Ultrasonography screening of carotid arteries in asymptomatic patients

Objective: to identify the most important predictors of carotid artery stenosis in ambulatory patients of Saratov and Saratov Oblast, using multivariate analysis, and to specify an ideal patient for ultrasonographic screening. Materials and methods. In 2014-2018, field consultations and ultrasonographic examinations were performed for asymptomatic patients with suspected carotid artery disease at outpatient clinics of Saratov and Saratov Oblast. Such patients were referred for screening by neurologists and general practitioners. The study encompassed 470 medical charts. The multivariate regression analysis was performed to identify independent predictors of carotid artery stenosis of 50 per cent or more. Results. Carotid artery stenosis of ≥30% was detected in 24.5% (i.e., 115 of 470) of study participants; of ≥50% in 10.2% (48 of 470) patients, and of ≥70% stenosis in 2.9% (14/470) of participants. The multivariate analysis revealed that the odds of finding stenosis of ≥50% in patients, selected by neurologists and general practitioners for ultrasonographic screening, were significantly higher in the presence of the following factors: age exceeding 72, male gender, acute cerebrovascular event in anamnesis > 6 months ago, atherosclerosis of leg arteries, and episodes of speech impairment. We developed the point scale for risk assessment. A point scale for risk assessment has been created. In the absence of prognostic factors, the absolute risk of detecting stenosis ≥50% was just 3%, with 1 point it was 16%, and with 4 points it amounted to >50%. Conclusion. Our analysis enabled us to specify the most significant predictors of carotid artery stenosis in patients observed at outpatient clinics of Saratov and Saratov Oblast, and to obtain a patient model helping to optimize optimize selection for ultrasonographic examination.

Experimental study of synthetic polymeric materials as a basis for developing advanced carrier matrices for cultivating limbal stem cells

Objective: to conduct an experimental study on the properties of three different types of synthetic polyester matrices, to carry out their comparative assessment, and to identify the optimal carrier for the cultivation and transplantation of limbal stem cells while eliminating limbal insufficiency. Materials and methods. Transparency, mechanical properties (strength, relative elongation at break, and elastic modulus), biocompatibility with corneal cell cultures were assessed, and duration of matrix biodegradation in vivo were studied. Results. In the course of our study, the optical and mechanical properties of matrices, made of polylactide-glycolide (PLG), polylactide-caprolactone (PLC) and poly-E-caprolactone (PCL), were studied. It has been experimentally shown that limbal stem cells of humans and rabbits, as well as human corneal epithelial cells, adhered to the surface of all types of the studied matrices. During the cultivation process, they retained the typical structure of the actin cytoskeleton, along with the ability to proliferate and migrate. Differences in the interaction of different cell cultures with different types of carriers were revealed. The biodegradation time of 5 μm thick PLC matrices was about 30 days. Conclusion. Our results obtained implied the possibility of using 5 µm thick PLC matrices as a carrier for cultured limbal stem cells.

Medicamentous therapy of stable coronary artery disease sensu the guidelines on myocardial revascularization

Objective: based on the Russian Federation multicenter registry data, to assess the comprehensiveness of medicamentous therapy in patients with stable coronary artery disease (CAD) from the perspective of 2018 European Society of Cardiology (ESC-2018) recommendations for myocardial revascularization and 2017 American Appropriate Use Criteria (AUC-2017) for the expediency of revascularization. Materials and methods. Anamnestic data of 1531 patients with stable CAD (average age: 61.7 ± 9.8 years; 76% men) were studied. The data source was the Russian Federation multicenter registry of patients with arterial hypertension, CAD, and chronic heart failure. We identified the prescription of optimal medical therapy (OMT) sensu ESC-2018, maximal anti-ischemic therapy (MAT) sensu AUC-2017, and compliance of drug therapy with ESC-2018 and AUC-2017 simultaneously. OMT included at least one anti-ischemic medication + antiplatelet agent + statin + short-acting nitrate + blocker of the renin-angiotensin system in the presence of hypertension, diabetes mellitus, or heart failure. MAT included at least two anti-ischemic pharmaceutical drugs. Compliance with these criteria was determined in the groups of patients who underwent, or did not undergo, myocardial revascularization, as well as among those, for whom invasive treatment was indicated as the first priority, as the second priority, or was not indicated at all, according to ESC-2018 and AUC-2017. Results. Among patients who received solely medicamentous therapy (n=924), OMT was prescribed in 18%, while in the revascularization group (n= 07), in 9% of cases (p <0.001). MAT was also prescribed more often in the conservative therapy group (34%) than in the revascularization group (24%): p = 0.001. OMT sensu ESC-2018 and AUC-2017 in the groups with, or without, intervention was prescribed in 3% vs. 7% of cases, respectively (p <0.001). Conclusion. According to the Russian Federation multicenter registry, medicamentous therapy of stable CAD complies with the provisions of European and American clinical guidelines for myocardial revascularization in a small proportion of patients, regardless of the chosen treatment tactics.

Optimizing the process of developing human blood vessel models

Objective: to optimize the process of blood vessel biomechanical modeling via developing models of cerebral arterial circle. Materials and methods. Biomechanical modeling requires development of a patient-oriented three-dimensional (3D) solid-state geometric model of the object under study. This task can be resolved by computed tomography (CT) or magnetic resonance imaging (MRI). We developed the program that implements the construction of blood vessel contours from separate slices of MRI in a semi-automatic mode. These contours are exported as saved curves in a specific format to SolidWorks, where they are used to create 3D models of blood vessels. The models obtained this way take into account individual characteristics of the vascular system structure of a particular patient, and can be used in the process of biomechanical modeling. Results. The results of the program implementation of the recursive frontal growth method for processing 2D slices of tomograms are presented. Conclusion. The developed software allows semi-automatic loading of DICOM images and obtaining flat cross-sections (MRI slices) of vessels on their basis, as well as transferring them for further processing into computer-aided design systems.

Using endoscopic hemithyroidectomy in patients with benign thyroid diseases

Objective: the development and assessment of endoscopic hemithyroidectomy technique improving visualization of anatomical structures and excluding the so-called conflict of instruments in the operative field. Materials and methods. We analyzed the treatment results of 103 patients who underwent hemithyroidectomy with endoscopic or traditional approaches during 2014-2018 at the S.R. Mirotvortsev Hospital of Saratov State Medical University. In terms of approach mode, patients were divided into two groups. The compression syndrome, functional autonomy of a thyroid, and results of a punch biopsy were indications to operation. Results. Unilateral vocal cord paralysis (UVCP) was diagnosed in one patient after traditional intervention, diminishing after 1.5 months; and in three patients after endoscopic hemithyroidectomy, diminishing anywhere between 7 days and 1.5 months. Signs of hypoparathyroidism were not found in any of the patient groups. There were no complications associated with the introduction of carbon dioxide. No conversion was required in any of the cases. Conclusion. Development, application and assessment of a new endoscopic hemithyroidectomy technique, which proved itself feasible, safe and provisioning highly esthetic outcome were conducted.