[Enhancement of the anti-ischemic kidney resistance by adaptive hypoxic conditioning and drug therapy].
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Biomedical subjects
Publications and source records attributed to V I Kirpatovskiĭ.
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The findings of ultrastructural analysis demonstrated essential changes in connective tissue cells and noncellular elements of veins after their cryopreservation at -50 degrees C and -196 degrees C. Contraction and round-up of endotheliocytes, disruption of their connections with basement membrane leading to subendothelial space widening, cytoplasm vacuolization and focal destruction of luminal plasmalemma are typical and general changes caused by cryopreservation. Dystrophy of different grades developed in connective tissues of media and adventitia. Deeper freezing negatively affects structural integrity of venous tissues. After the use of conserving solutions (Eurocollins and Scientific Research Institute of Traumatology and Orthopaedics) necrotized endotheliocytes were absent and endothelial lining was preserved in major part of the vein surface studied even following its deep freezing which supports the conclusion on the cryoprotective effect of the solutions.
The motor restraint stress in rats was treated with permanent magnetic fields of the geomagnetic strength generated by authors' apparatus GEOMAG. The GEOMAG therapy appeared to expedite reduction in blood levels of mid-molecular toxic products in stressed animals. Determination of the Ca-ATPase activity showed that 3 to 6 hours of treatment significantly (up to 34% and 29%, respectively) decreased the inhibiting activity of plasma. This decrease was particularly marked after the geomagnetic field therapy. These results give evidence that the GEOMAG-produced geomagnetic fields favor more rapid detoxication of stressed organism through more effective neutralization of metabolites in the spleen and renal excretion. Hence, the method shows promise with regard to the postflight rehabilitation of flying personnel.
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S-stents were introduced to the upper urinary tracts of experimental dogs on a period from 1 week to 11 months. It was found mild ureter dilation, the increased ureter pressure, refluxes along the upper urinary tract, the lowered flow resistance during perfusion and diuretic loads. Isolated ureter wall fragments demonstrated the diminished contractility in vitro, and the mode of their contractile force adrenergic regulation was modified. The reduced ureter pressure during large flows after indwelling S-stents to the ureters may be the factor that facilitated the renal and ureter stones removing but the decreased contractility and ureter refluxes emphasized that the period of stent implantation to the upper urinary tracts must be pathogenetically and clinically evident.
Vitamin E was quantified in the cortex and medulla of human, rat, canine and rabbit kidneys. For the all species investigated the vitamin concentrations, calculated both per g wet tissue weight and per mg tissue protein, was shown to be 1.4-2.2 times higher in medullary layer than in cortical one. The least vitamin E levels were observed in rabbit kidneys of which the cortical and medullary concentrations were 4.4 +/- 0.3 mkg (M +/- SEM) and 6.3 +/- 0.56 mkg per g wet tissue weight, respectively. In human renal cortex and medulla the vitamin concentrations were found to be 10.6 +/- 0.66 mkg and 16.2 +/- 1.1 mkg per g wet tissue weight, respectively. Close values were observed for other species studied as well. The increased renal medullary vitamin E concentrations are likely related to the higher phospholipid metabolism and enhanced prostaglandin synthesis in this tissue.
Vitamin E was quantified in tumor tissue obtained from 17 patients with renal cell carcinoma (RCC). The tumors consisted of two groups: (I) represented primarily by clear cells (10 cases) and (II) without predominant appearance of those cells (7 cases). Vitamin E concentration in tumor tissue was compared with that in intact tissue sites of the kidney. The vitamin content in intact renal medulla was shown to be 1.5 times higher than in intact cortex. Vitamin E level in group I tumors was shown to be on average 15 and 10 times as much as in intact renal cortex and medulla, respectively. The vitamin concentration in group II tumors, as compared with the above intact renal tissues, was 7- and 5-fold higher, respectively. In spite of the high tumor total lipids levels, the vitamin E concentration, calculated per mg total lipids, was still higher in tumor tissue than in the normal renal tissues. This finding was especially demonstrable for the group I tumors. In the benign renal tumor angiomyolipoma vitamin E concentration, calculated on a wet weight basis, was higher than in intact renal tissue, but no differences were observed when a per total lipids calculation was performed. Vitamin A concentration determined in the tumor samples obtained from 6 patients was the same as in intact cortex.
The aim of the study is investigation of possibility to bypass small and medium-size arteries with cryopreserved artery allografts, storing 7-10 days at -196 degrees C under the protection of 15% dimethylsulfoxide. In experiments on 40 rabbits were placed a region of the left renal artery by cryopreserved bioprosthesis. Graft patency was 80% after observation up to 6 months. By angiography it was 8 cases of graft thrombosis (all during the 1st week after implantation) and 5 cases of moderate graft dilation (in 4 of them it was accompanied with stenosis of distal anastomosis). In 20 dogs we replaced a region of the femoral artery by cryostoring bioprosthesis. It was only one case of graft thrombosis which occurred on month 2 after the implantation during 1-year follow-up. After 3 months in 3 cases there developed 3 cases of diffuse narrowing of graft lumen without decreasing of blood flow through the prosthesis. Later, the graft lumen did not change. Histological investigations have revealed a viability of cryopreserved vessels, its almost complete de-endothelialization at 3 days and total re-endothelialization 2 weeks after implantation. During the first 2 weeks there were morphological events of graft rejection, which disappeared after 3 months.
Investigations on the isolated pieces from upper part of human ureters and upper and lower parts of dog ureters were performed. Isometric contractions during electrical stimulation in Lock solution (37 degrees C) and their changes after adrenomimetic drug and adrenoblocking drug perfusion were studied. The pieces of human ureters had more average weight and rest tension, but less isometric tension during rhythmic electrical stimulation and more pronounced hypersodium contracture in contrast to dog ureters. Adrenaline and noradrenaline augmented contractions of human and dog ureters. Isadrin increased the contractility of the upper parts of human ureters and the lower parts of dog ureters, but decreased--the upper segments of dog ureters. Adrenoblocking agents modified the action of adrenomimetics. After blockade of alpha-receptors by phentolamine, isadrin decreased the contractions of all studied pieces of ureters, however, adrenaline decreased contractility of human ureters but increased--dog ureters. It may be proposed, that there are alpha 1 and alpha 2 receptors, that stimulated the contractility of human and dog ureters, beta 1 adrenoreceptors, that inhibited the contractions during blockade of alpha-receptors, and beta 2-receptors, that in these conditions increased the contractions of dog ureter but decreased the contractions of human ureters.
Lipid peroxidation (LPO) stimulated by ascorbate was studied in renal cortex of 20 rats with nephrotoxic nephritis (NTN) and of 9 rats with proteinuria induced by a 3-day course of i. p. injections of the human serum albumin. At the early stages of NTN (0.5 h. and 3 h.) LPO activities were of the same values as in control rats. A small decrease in renal cortex LPO was found on the 4-th day of NTN when nephrotic syndrome has been developed. A significant reduction in LPO activity was observed on the 16-th day of NTN characterized by a more pronounced nephrotic syndrome. LPO activity in renal cortex of the rats with albumin overload proteinuria was also reduced. An inhibitory effect of proteinuria on LPO activity in kidney is discussed.
The method of experimental megaureter modelling in dogs that is based on the operative damage of the ureter segment is described. Obstructive megaureter was found in 100% of "devitalization" of the ureterovesical junction and in 59% of "devitalization" of the middle third of ureter. Progression of megaureter symptoms and reduction of evacuator-secretory function on the side of modelling operation without anatomical narrowing of the ureter lumen in 41% of experiments pointed to the actual role of the functional obstruction in pathogenesis of this hard syndrome. In vitro methods demonstrated the decrease of contractility of the "devitalized" fragments and also of above and below situated segments of megaureter. Urodynamic investigations showed the signs of the bioelectrical disturbance in the megaureter wall and the disorder in excitement and contraction of the megaureter, deterioration of the reactivity of the megaureter on the functional loading tests.
We investigated the intensiveness of the cell proliferation, number of mononuclear leucocytes (MNL) and production of interleukin-1 (IL-1) in glomerular cell cultures of rats with nephrotoxic serum (NTS) nephritis and control (C) rats. Five days after intravenous injection of nephrotoxic serum from rabbits the glomeruli were isolated, treated with collagenase and cultured over a period of 20 days. In cultures the number and intensity of mesangial cell proliferation in the NTS group were significantly higher than in the C group. Thus, the intensive mesangial cell proliferation in experimental nephrotoxic serum nephritis is related to infiltration of glomerulus by MNL of bone marrow origin with increased production of IL-1.
An experimental study on rat hearts using continuous recording of myocardial tension showed that the addition of various groups of drugs to the solution had negative effects on heart function. Positive effect was achieved when cardioplegia was combined with the pretreatment of animals with anti-ischemic drugs (alpha-tocopherol, dimethylsulfoxide) as well as preliminary oxygenation of the medium. Possible mechanisms of these myocardial effects are discussed.
An experimental study on rat hearts has demonstrated that cardioplegic solutions, apart from their protective effect, activate energy-consuming calcium redistribution process. Presented data permit qualitative and quantitative assessment of myocardial changes and a prompt evaluation of arrested heart's functional status.