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Purpose: to create a protocol for complex cryoconservation of blood vessels in polydimethylsiloxane to create tissue-specific matrices. Material and Methods. The material ofthe study was the iliac arteries from postmortem donors, seized in the multi-organ donation, rejected for unclaimed and disposed of later. Polydimethylsiloxane was used as a coolant (PDMS) with a viscosity of 5-25 centistokes (Spectroplast, Russia). Bench testing of cooling and heating ofthe blood vessel in PDMS, testing of heating and cooling of PDMS up to operating temperatures (-80°C) in different ways and variants of its thermal insulation, assessment of different cooling rates ofthe vessel during cryoconservation, modeling of 3 types of working chambers for cryoconservation, sterilization and defrosting of up to 10 vessels, modeling of cryoconservation and thawing of vessels in PDMS under different conditions, selection of substrates from silicone and plastic for uniform fixation of vessels which are of size or size in the working chambers or without them. Results. The developed protocol allows cryopreserved from 1 to 10 or more vessels of all basic sizes both immediately after removal and after transportation to the laboratory, to vary the cooling rate from 1.5 to 300°C/min and above, to be used with different levels of laboratory equipment, as with liquid nitrogen, dry ice, and only with a medical freezer. Conclusion. The developed protocol allows to apply it in cases of complex cryoconservation of blood vessels to create tissue-specific matrices and can be recommended for preclinical testing.

Aim: to investigate potential cryo- and radioprotective properties of a polydimethylsiloxane of low viscosity to provide safe and reliable cryopreservation and radiation sterilization of human cadaveric vascular allografts. Material and methods. A consecutive experimental set-up was carried out to establish polydimethylsiloxane (further — PDMS) protective endocellular properties. For this purpose a high-densitymesenchymal stem cells suspension was cryopreserved with 10% DMSO solution; PDMS exocellular protective properties were assessed by cyclic cryoconservation of ^femoral artery segments, while PDMS potential radioprotectiveproperties were assessed by gamma irradiation — induced sterilization of 3 cryopreserved femoral artery segments with gross length about 3cm, and for control grafts a slightly changed protocol with glycerin was used. In this study the dynamic viscosity of all cryopreserved vessels was analyzed with using specially designed experimental device, also electron scanning microscopy with lanthanide cells staining and routine hematoxylin — eosin cell staining were applied. Results. We have demonstrated a prominentexocellular protective effect of PDMS confirmed by a SEM and histological results, and also its mediated radioprotective effect, in particular because of its safer preliminary cryopreservation procedure. Conclusion. Use of PDMS for a cryopreservation and gamma sterilization showed its rationality, however requires further modification of protocols and additional researches.

Data on application of decellularized scaffolds and tissue-engineered vascular conduits in the field of cardiovascular surgery have been analyzed, and also techniques for their procurement have been studied. For finding, selection and synthesis resources of research data from the systems Pubmed, ScienceDirect were used. The preference was given to the most informative, comprehensive and contemporary publications.

Aim: to verify new techniques for human cadaveric vascular allografts cryopreservation, thawing and sterilization for the tissue engineering purposes. We use polydimethylsiloxane (PDMS) as a well-known, promising coolant. This allowed us to completely omit any cryoprotective or vitrifying solutions. Using of PDMS also makes possible an applying these allografts directly after freezing and decellularization and also it will also provide an opportunity to develop secure protocols of tissue— engineered vascular conduits cryopreservation. Matherial and methods. After mathematical modeling of cooling process and its validation the experiment for sealed (isolated) freezing at low temperature conditions of 30 femoral arterial segments has been conducted. The segments were at least 10 cm in length and taken from 15 cadaveric donors in the age of 65-85 years. The freezing process was carried out using the abovementioned coolant— PDMS, and then physico-mechanical properties of these allografts were evaluated with the special Instron machine. According to the results obtained, a modeling of their sterilization conditions was conducted (the grafts were freezed). Results. By physico-mechanical properties validation and restricted histological analysis it was shown that there was an accordance between freezed/thawed allografts properties and native vessels. Conclusion. The abovementioned approach for allografts cryopreservation and thawing was efficient enough for further work in this direction.

Aim: to study immunogenetic markers of predisposition to the development and protection for Crohn's disease in adults population of the Moscow region. Material and methods. The study included 53 samples of peripheral blood of patients with Crohn's disease in the Moscow region. The control group was represented by 1,700 samples of umbilical cord blood is healthy newborns. Revealing HLA antigens at low level performed by SSO method on DynalRELI 48 processor. The results received with ambiguous interpretation was using PCR-SSP method (Ivitrogen). Results. Were found the positive and negative associations of groups of HLA alleles with clinical form, the course of Crohn's disease and response to steroid treatment, in particular revealed that, predisposition to the development for Crohn's disease in women and with sensitivity to steroid treatment in this disease associated allele group C*12, to the characteristic restricting markers such as Crohn's disease include the В 38 and A*11 markers nonrestricting, nonpenetrating noninflammatory type groups are alleles B*56 and C*14 and C*14 is also associated with the risk of Crohn's disease in men, characteristic markers of protection to the development of the disease crown with chronic relapsing and severe clinical course are DQB1*02 and DQB1*03, respectively. Conclusion. These results demonstrate the need for studies of gene polymorphism HLA-system, not only in relation to the disease in general, but in selected patients with clinical groups.