The methods of donor heart preservation are aimed at minimizing graft dysfunction caused by ischaemia-reperfusion injury (IRI) which inevitably occurs during the ex vivo transport interval. At present, the standard technique of heart preservation is cardiac arrest followed by static cold storage in a crystalloid heart preservation solution (HPS). This technique ensures an acceptable level of heart protection against IRI for <6 h. In clinical trials, comparable levels of myocardial protection against IRI were provided by various HPSs. The growing shortage of donor hearts is one of the major factors stimulating the development of new techniques of heart preservation. Here, we summarize new HPS formulations and provide a focus for optimization of the composition of existing HPSs. Such methods of donor heart preservation as machine perfusion, preservation at sub-zero temperature and oxygen persufflation are also discussed. Furthermore, we review experimental data showing that pre- and post-conditioning of the cardiac graft can improve its function when used in combination with cold storage. The evidence on the feasibility of cardiac donation after circulatory death, as well as the techniques of heart reconditioning after a period of warm ischaemia, is presented. The implementation of new techniques of donor heart preservation may contribute to the use of hearts from extended criteria donors, thereby expanding the total donor pool.

The cardioprotective effects of necroptosis inhibitors necrostatin-1 and necrostatin-5 were studied on the isolated heart model in rats. Intraperitoneal injection of necrostatin-1 (1.65 mg/kg) or necrostatin-5 (2.46 mg/kg) 60 min before reperfusion of the isolated heart reduced the infarction zone caused by 30-min global ischemia and 120-min reperfusion. Intracoronary injection of necrostatin-1 (44.5 μmol/liter) caused an increase of left-ventricular systolic pressure, that is produced a positive inotropic effect, but did not reduce the infarction zone.

Type 2 diabetes (DM2) could be reproduced in rats with alimentary obesity by using low doses of streptozotocin (LD-STZ) as well as STZ in high doses with preliminary nicotinamide (NA) administration. However, STZ could induce tubulotoxicity. Aim. To develop rat model of DN in NA-STZ-induced DM2 and compare it with LD-STZ-model in order to choose the most relevant approach for reproducing renal glomerular and tubular morphofunctional diabetic changes. Starting at 3 weeks after uninephrectomy, adult male Wistar rats were fed five-week high-fat diet and then received intraperitoneally either LD-STZ (40 mg/kg) or NA (230 mg/kg) followed by STZ (65 mg/kg). Control uninephrectomized vehicle-injected rats received normal chow. At weeks 10, 20, and 30 (the end of the study), metabolic parameters, creatinine clearance, albuminuria, and urinary tubular injury markers (NGAL, KIM-1) were evaluated as well as renal ultrastructural and light microscopic changes at weeks 20 and 30. NA-STZ-group showed higher reproducibility and stability of metabolic parameters. By week 10, in NA-STZ-group NGAL level was significantly lower compared to LD-STZ-group. By week 30, diabetic groups showed early features of DN. However, morphofunctional changes in NA-STZ-group appeared to be more pronounced than those in STZ-group despite lower levels of KIM-1 and NGAL. We proposed a new rat model of DM2 with DN characterized by stable metabolic disorders, typical renal lesions, and lower levels of tubular injury markers as compared to LD-STZ-induced diabetes.

BackgroundThe Krebs-Henseleit buffer is the best perfusion solution for isolated mammalian hearts. We hypothesized that a Krebs-Henseleit buffer-based cardioplegic solution might provide better myocardial protection than well-known crystalloid cardioplegic solutions because of its optimal electrolyte and glucose levels, presence of buffer systems, and mild hyperosmolarity.MethodsIsolated Langendorff-perfused rat hearts were subjected to either global ischemia without cardioplegia (controls) or cardioplegic arrest for either 60 or 180 min, followed by 120 min of reperfusion. The modified Krebs-Henseleit buffer-based cardioplegic solution (mKHB) and St. Thomas’ Hospital solution No. 2 (STH2) were studied. During global ischemia, the temperatures of the heart and the cardioplegic solutions were maintained at either 37°C (60 min of ischemia) or 22°C (moderate hypothermia, 180 min of ischemia). Hemodynamic parameters were registered throughout the experiments. The infarct size was determined through histochemical examination.ResultsCardioplegia with the mKHB solution at moderate hypothermia resulted in a minimal infarct size (5 ± 3%) compared to that in the controls and STH2 solution (35 ± 7% and 19 ± 9%, respectively; P < 0.001, for both groups vs. the mKHB group). In contrast to the control and STH2-treated hearts, no ischemic contracture was registered in the mKHB group during the 180-min global ischemia. At normothermia, the infarct sizes were 4 ± 3%, 72 ± 6%, and 70 ± 12% in the mKHB, controls, and STH2 groups, respectively (P < 0.0001). In addition, cardioplegia with mKHB at normothermia prevented ischemic contracture and improved the postischemic functional recovery of the left ventricle (P < 0.001, vs. STH2).ConclusionsThe data suggest that the Krebs-Henseleit buffer-based cardioplegic might be superior to the standard crystalloid solution (STH2).

Cardioprotective properties of dimethyl sulfoxide (DMSO) were studied in the isolated rat heart model. Intraperitoneal administration of DMSO to animals for 3 days before the experiment, but not addition of DMSO to the perfusate, reduced infarction size. Both intraperitoneal and intracoronary administration of DMSO reduced the severity of postischemic left-ventricular dysfunction.

No abstract

An essential element of any modern technology for the production of metal for transport vehicles --including railroad wheels --is treatment of the metal outside the furnace and its vacuum degassing. There are several methods of vacuum degassing in use, each having its advantages and disadvantages. The ladle method was chosen for the open-hearth shop at the Nizhnedneprovsk Pipe Plant, due to the specifics of OH steelmaking and the limited potential for obtaining a low-sulfur product on the one hand and, on the other hand, the increasing demand for low-sulfur steel in the world market.The following must be done for successful vacuum degassing: prevent furnace slag from entering the ladle or remove it if it does; provide for additional heating of the metal to compensate for the substantial heat loss from degassing and allow additional desulfurization with the introduction of slag-forming materials; correct the chemical composition of the metal, if necessary. The degassing system also provides for blowing of the metal with argon.These operations are performed on a "furnace-ladle" unit. The nature of the operations described above shows that the vacuum-degassing unit is actually a complex of equipment which in addition to the basic components includes a high-voltage substation with a filter-compensation unit, a water recycling system, a waste-beat boiler, a draft system for removing and cleaning outgoing gases, a section for monitoring the concentrations of gases dissolved in the metal, and other important components. The plant contracted with the Mannesman--Demag company to build such a system at its facility. The equipment layout was the responsibility of Ukrgipromez (Ukrainian State Institute for the Planning of Metallurgical Plants).In order to fit the equipment into the open-hearth shop, OH furnace No. 1 was taken out of service, while OH furnace Nos. 2 and 3 were provided with oscillating chutes to control the distribution of metal and divert the furnace slag. All of the equipment of the complex was supplied by subcontractors of Mannesman--Demag.Except for a few operations, the entire complex is completely automated. All of its components can be controlled from the central control post. Accomplishing this required the use of special programs, sophisticated computer technology, and debugging routines. The contract provides for two levels of system automation. All information on the condition of the controlsystem components and the measured process parameters is displayed on three monitors positioned in front of the operator. The computer keyboard is used to retrieve needed data to the monitor screen and control the system elements. The first level of the system provides for visual recording of process parameters, while the second level records the parameters in the memory of a special computer, retrieves cumulative data to the screen at the operator's request, and prints it out on demand.The process equipment and the hardware and software of the automatic control system (ACS), delivered, installed, and now being ...

The differential mode of the grazing-incidence diffraction is employed for t h e characterization of a thin Ga, -,AI,As/GaAs [OOI] heterostructure. Using a high-resolution detector system a conventional x-ray source is appropriate to record the fine structure of the diffraction curve.T h e quality of experimental curves permits u s to detect the thickness of both the non-ditfracting top part and the perfect crystalline portion of the layer. Their quantitative determination results from simulation of the curve by means of t h e dynamical and the kinematic theory. Both yield nearly the same crystalline thickness; however, they differ somewhat for t h e top part. A quantitative interpretation of the real structure of sample is impossible, due to the limited exDerimental resolution.