[Bioprinting technologies in ophthalmology]. / Tekhnologii biopechati v oftal'mologii.

Bioprinting allows additive fabrication of bioengineered constructs with defined two- or three-dimensional organization using live cells, biopolymers and other materials. This article reviews main bioprinting technologies and their capabilities in clinical and experimental ophthalmology. Analysis of literature sources helped reveal and describe the main types of bioprinting technologies: inkjet, laser-assisted, and extrusion. Extrusion bioprinting is the most widely used method, providing the ability to use various types of bioinks and a wide range of cell concentrations. The following materials can be used as the base for bioinks: alginate, collagen, gelatin, hyaluronic acid, chitosan, fibrin, as well as their different combinations. These materials can be modified for best bioprinting properties by adding various functional groups. The major directions of application of bioprinting technologies in ophthalmology are tissue engineering for regenerative medicine and fabrication of model systems for fundamental and preclinical studies. Experiments in creating a bioprinted cornea are being conducted in the field of regenerative medicine. Furthermore, there are studies on fabricating retinal tissue equivalents, although tissue engineering of this structure is a task of great complexity. Model systems, which can be fabricated by bioprinting, are represented by tissue equivalents of ocular structures and the appendages of the eye, as well as by microphysiological organ-on-a-chip systems. Another promising application of bioprinting is fabrication of biocompatible implantable electrode arrays for visual neuroprostheses.

The Chick Embryo and Its Structures as a Model System for Experimental Ophthalmology.

The possibilities of using the chick embryo and its individual structures as a model system in experimental ophthalmology are considered. Cultures of the retina and spinal ganglia from chick embryos are used in the development of new methods for the treatment of glaucomatous optic neuropathy and ischemic optic neuropathy. The chorioallantoic membrane is used for modelling vascular pathologies of the eye, screening of anti-VEGF drugs, and assessing biocompatibility of implants. Co-culturing of chick embryo nervous tissue and human corneal cells makes it possible to study the processes of corneal reinnervation. The use of chick embryo cells and tissues in the "organ-on-a-chip" system opens up wide opportunities for fundamental and applied ophthalmological studies.

[Application of the organ-on-a-chip technology in experimental ophthalmology]. / Primenenie tekhnologii «organ-na-chipe¼ v eksperimental'noi oftal'mologii.

Organ-on-chip is a microfluidic device that can reproduce in vitro the minimal functional unit of an organ or system of organs and model various physiological processes and body structures with high accuracy. This review covers the main approaches to the use of the organ-on-chip technology in modern experimental ophthalmology. The analysis of literature sources revealed the following main applications of the organ-on-chip technology in ophthalmology; the technology allows modeling the anterior eye surface and its diseases, such as dry eye syndrome, as well as disorders of the posterior segment of the eye such as age-related macular degeneration, diabetic macular edema, diabetic retinopathy, glaucoma. Culturing of eye tissues in microfluidic systems helps identify the toxic effects and pharmacological activity of new compounds, and provides an opportunity for deeper understanding of the normal physiology of the eye and the pathogenesis of ocular diseases. In addition, the technology can reduce the cost and duration of experiments. Thus, the organ-on-a-chip technology has a great potential in the field of experimental ophthalmology and preclinical trials of new ophthalmic drugs.

[Modern concepts of bionic vision]. / Sovremennye kontseptsii bionicheskogo zreniya.

Loss of vision is a pressing medical and social problem leading to profound disability, loss of ability to work, serious alterations in the psycho-emotional state, and a decline of the quality of life. When conservative or surgical treatment can not help restore vision, the use of visual prosthesis - bionic eye - can be an effective solution. This review covers the main modern approaches to the development of visual prosthetic systems. Analysis of publications revealed that there are several main approaches to visual prosthesis differing primarily by the anatomical structure targeted for stimulation in order to activate visual sensations. The most significant among them are retinal prostheses, optic nerve stimulation, and cortical visual prostheses. Currently, retinal prostheses such as ARGUS II demonstrate the most successful results, since the stimulation of the surviving neural structures of the retina is a relatively easy task, but their field of application is limited to diseases associated with pathological changes in photoreceptors. The development of cortical visual prostheses is more difficult, but in the future they may allow using more stimulation channels to obtain a more detailed visual perception. In addition, cortical visual prostheses are universal, as they do not require preservation of any structures of the visual organ, only the primary visual cortex.

Estimation of Decellularization and Recellularization Quality of Tissue-Engineered Constructions by the Chemiluminescence Method.

It was found that the chemiluminescence intensity in native and recellularized tissues of rat muscular organs as well as in their decellularized scaffolds can serve as an express criterion that, along with ultrastructural analysis, makes it possible to perform quantitative assessment of the viability of cellular structures in biological samples of the diaphragm.

[THE EXPERIENCE OF ANAESTHESIA MANAGEMENT FOR SENSING OF NASOLACRIMAL DUCT IN CHILDREN].

Despite low invasiveness, lacrimal passages, intubation in children requires general anaesthesia to prevent traumatic and neurological complications. General anaesthesia with sevoflurane is optimal for technical simplicity, safety and controllability. Methods of face mask inhalation anesthesia with halothan and sevoflurane were compared in 996 patients. The authors have developed their own standart of performing the face mask inhalation anesthesia with sevoflurane in children during lacrimal passages intubation. This allowed to minimize the number of intra- and postoperative complications in children, to reduce period of postanesthetic observation, to advance the peroral compensation of fluid deficit.

Pharmacological correction of changes in the lung-placenta system under experimental conditions.

Pathological changes in the fetoplacental complex and lung-placenta system were observed in rats with experimental gestosis produced by long-term feeding of a high-sodium diet. We revealed a decrease in the weights of the placenta and fetus, pulmonary fibrinolytic dysfunction, and increased production of cortisol. The course of fraxiparine treatment in animals with experimental gestosis decreased coagulation activity of the arterial blood, increased the weights of the placenta and fetus, and reduced the concentration of stress hormone cortisol.

Disorders in the lungs-placenta system under conditions of experimental gestosis in rats.

Study of the arteriovenous difference in hormone levels and hemostasis parameters in rats with experimental gestosis induced by hyper-sodium diet showed decreased production of progesterone, increased level of hydrocortisone (resultant from its increased production and additional release of the hormone by the lungs), hypercoagulation, and retarded fetal development. Involvement of the lungs into the maintenance of optimum rheological parameters of arterial blood and a relationship between the level of fetoplacental hormones and the function of pulmonary fibrinolytic filter were detected.

Pharmacological correction of hemostasis-regulating function of the lungs in rats with uncomplicated pregnancy and experimental gestosis.

Fetal growth retardation, hypercoagulation, and changes in pulmonary fibrinolytic activity were observed during experimental gestosis induced by long-term feeding of a high-sodium diet. The course of fraxiparine treatment to correct gestosis improved hemostasis-regulating lung function, decreased coagulation activity of the arterial blood, and increased the weights of the placenta and fetus.

Blood clotting disorders in gestosis and pulmonary mechanisms of their compensation.

We studied blood coagulation system in women with uneventful pregnancy and with gestosis and evaluated the hemostasis-regulating role of the lungs in pregnancy and gestosis. We found a correlation between disorders in the pulmonary fibrinolytic function and severity of gestosis, and demonstrated the role of compensatory pulmonary mechanisms in the maintenance of adequate microcirculation in maternal organism and in the mother-placenta-fetus system. Prognostic and diagnostic criteria of gestosis and its complications are proposed.