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An analytical method for studying DNA degradation by electrophoresis after cell lysis and visualization of DNA fragments with fluorescent dye, comet assay, was used to evaluate the viability of the endothelial layer of human arterial grafts with the aim of identifying the procedure that will least damage the tissue before cryopreservation. Four groups of samples were studied: cryopreserved arterial grafts that were thawed in two different ways, slowly lasting 2 hours or rapidly for approx. 7 minutes. Arterial grafts that were collected as part of multiorgan procurement with minimal warm ischemia time. Cadaveric grafts were taken as part of the autopsy, so they have a more extended period of warm ischemia. The HeadDNA (%) parameter and others commonly used parameters like TailDNA (%). TailMoment, TailLength, OliveMoment, TailMoment to characterize the comet were used to assess viability in this study. The ratio of non-decayed to decayed nuclei was determined from the values found. This ratio for cadaveric grafts was 0.63, for slowly thawed cryopreserved grafts 2.9, for rapidly thawed cryopreserved grafts 1.9, and for multi-organ procurement grafts 0.68. The results of the study confirmed the assumption that the allografts obtained from cadaveric donors are the least suitable. On the other hand, grafts obtained from multiorgan donors are better in terms of viability monitored by comet assay. Keywords: Arterial grafts, Cryopreservation, Cadaveric, Multiorgan procurement, Viability, Comet assay.

The authors present their contribution to the improvement of methods suitable for the detection of the freezing and thawing damage of cells of cryopreserved venous grafts used for lower limb revascularization procedures. They studied the post-thaw viability of cells of the wall of cryopreserved venous grafts (CVG) immediately after thawing and after 24 and 48 h culture at +37 °C in two groups of six CVG selected randomly for slow thawing in the refrigerator and rapid thawing in a water bath at +37 °C. The grafts were collected from multi-organ and tissue brain-dead donors, cryopreserved, and stored in a liquid nitrogen vapor phase for five years. The viability was assessed from tissue slices obtained by perpendicular and longitudinal cuts of the thawed graft samples using in situ staining with fluorescence vital dyes. The mean and median immediate post-thaw viability values above 70% were found in using both thawing protocols and both types of cutting. The statistically significant decline in viability after the 48-h culture was observed only when using the slow thawing protocol and perpendicular cutting. The possible explanation might be the "solution effect damage" during slow thawing, which caused a gentle reduction in the graft cellularity. The possible influence of this phenomenon on the immunogenicity of CVG should be the subject of further investigations.

Purpose: To assess the efficacy of percutaneous techniques in managing paediatric liver transplantation complications., Material and Methods: We carried out 105 paediatric cadaveric donor liver transplantations at our centre from 2001 to 2018. Percutaneous techniques were used to treat 25 cases involving transplantation complications in 23 patients. Biliary complications were treated in 14 cases (13.3%): 10 patients had bile duct obstruction, and 4 had biliary leaks. Vascular complications were treated in 11 cases (10.5%): 5 hepatic artery (HA) stenoses/occlusions, 2 inferior vena cava (IVC) stenoses, and 1 portal vein (PV) stenosis. Other interventions involved embolisation of the superior mesenteric artery branch to manage gastrointestinal bleeding in 2 patients and embolisation of an arteriobiliary fistula in 1 patient., Results: Biliary: We carried out external-internal drainage and balloon dilatation of stenoses in 12 cases. The external-internal drainage catheter was removed after 6-8 weeks in 7 patients, with the remaining 5 patients with persisting stenosis assigned for retransplantation. We failed to cross anastomotic occlusions in 2 patients before completing the procedures using external drainage; both individuals subsequently underwent retransplantation. Vascular: We performed PTA/stenting of HA stenoses/occlusions in 4 out of 5 patients. After the procedure, all 4 patients showed liver function normalisation. All 3 cases of embolisation were technically and clinically successful. Both IVC and PV stenoses treated with dilatation/stenting were also successful., Conclusions: Percutaneous techniques used to treat biliary and vascular complications after liver transplantation in paediatric patients are safe and efficient.

Background: The aim of our study was to assess the impact of different thawing protocols on morphological changes arising in cryopreserved human saphenous vein grafts., Methods: The study was performed in 12 saphenous vein grafts harvested in brain death donors. Storage in the vapor phase of liquid nitrogen for 3 or 5 years followed. Two thawing protocols were tested: slow thawing in a refrigerator at temperature +4°C for 2 hr and rapid thawing-in a water bath at +37°C. Grafts were processed for scanning electron microscopy. Comparisons of continuous parameters under study between experimental groups were performed using the t-test (age, cold ischemia time, exposure to cryoprotectant, time of storage, total thawing time, mean thawing rate, morphology scoring of thawed HSVG) and the median test (HSVG length). Categorical parameters (sex and blood group) were formally tested using the chi-square test., Results: All samples were evaluated according to morphological changes and scored in terms of morphologically intact endothelium, confluent endothelium with structural inhomogeneity, disruption of the intercellular contacts, separation of the endothelial cells, complete loss of the endothelium, and damage of the subendothelial layers. There is no statistically significant difference between the sample sets at the significance level of 0.05. There was no association with donors' age, sex, and time of storage., Conclusions: Human cryopreserved saphenous vein grafts in our experimental work showed no difference in terms of structural deterioration of the endothelial surface and basal membrane depending on different thawing protocols used., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Impaired myocardial bioenergetics is a hallmark of many cardiac diseases. There is a need of a simple and reproducible method of assessment of mitochondrial function from small human myocardial tissue samples. In this study we adopted high-resolution respirometry to homogenates of fresh human cardiac muscle and compare it with isolated mitochondria. We used atria resected during cardiac surgery (n = 18) and atria and left ventricles from brain-dead organ donors (n = 12). The protocol we developed consisting of two-step homogenization and exposure of 2.5% homogenate in a respirometer to sequential addition of 2.5 mM malate, 15 mM glutamate, 2.5 mM ADP, 10 μM cytochrome c, 10 mM succinate, 2.5 μM oligomycin, 1.5 μM FCCP, 3.5 μM rotenone, 4 μM antimycin and 1 mM KCN or 100 mM Sodium Azide. We found a linear dependency of oxygen consumption on oxygen concentration. This technique requires < 20 mg of myocardium and the preparation of the sample takes <20 min. Mitochondria in the homogenate, as compared to subsarcolemmal and interfibrillar isolated mitochondria, have comparable or better preserved integrity of outer mitochondrial membrane (increase of respiration after addition of cytochrome c is up to 11.7±1.8% vs. 15.7±3.1%, p˂0.05 and 11.7±3.5%, p = 0.99, resp.) and better efficiency of oxidative phosphorylation (Respiratory Control Ratio = 3.65±0.5 vs. 3.04±0.27, p˂0.01 and 2.65±0.17, p˂0.0001, resp.). Results are reproducible with coefficient of variation between two duplicate measurements ≤8% for all indices. We found that whereas atrial myocardium contains less mitochondria than the ventricle, atrial bioenergetic profiles are comparable to left ventricle. In conclusion, high resolution respirometry has been adapted to homogenates of human cardiac muscle and shown to be reliable and reproducible., Competing Interests: The authors have declared that no competing interests exist.

Thanks to an increased number of living-donor kidney transplants the IKEM transplant program offers the possibility of obtaining adipose tissue for scientific purposes from patients with varying degrees of atherosclerosis. Surgery mainly addresses vascular complications of this disease. On the other hand, surgery may also be the reason for the development and acceleration of atherosclerosis - for instance, acceleration of atherosclerosis in the living kidney donor, particularly if, although meeting internationally recognized donation criteria, the donor actually suffers from metabolic syndrome. The effort to refine the examinations of living kidney donors in terms of eliminating the risk of developing atherosclerosis is a long-term project. The aims are to determine the risk factors for living kidney donors and to prevent long-term complications after donation. The paper gives a detailed description of the technique of adipose tissue collection from a living kidney donor and of the experimental model for the research of atherosclerosis.The project has the potential to increase the safety of living kidney donation and to enhance our present knowledge of atherosclerosis development mechanisms.