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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Investigations were carried out by means of an autologous, heterotopic model for kidney transplantation applied to dogs. Duration of cold ischemia was 48 h. Four experimental groups were arranged. During the first 20 min following revitalization of the transplanted kidney, group 1 (HTK solution/80 cm perfusion height) showed a significant glomerular and tubular malfunction. In group 2 (HTK solution/120 cm perfusion height), only four urinary proteins with molecular weights of 25 kDa, 67 kDa, 100 kDa and > 100 kDa were found. The excretion of higher molecular proteins receded over the 20-min period of observation. In both group 3 (HTK/aspartate solution) and group 4 (HTK/tryptophan solution) the quantity of excreted glomerular and tubular protein was well above that of group 2. As opposed to the "Tryptophan" group, a complete restoration of renal function was observed in the "Aspartate" group after 4 weeks. In general, the "standard" HTK protective solution delivered with 120 cm perfusion pressure gave the most favorable results, with the lowest levels of proteinuria and a satisfactory recovery of renal function after revitalization.
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PMID:Effects of various HTK solution regimens on proteinuria after renal transplantation in dogs. 883 94

This study investigates firstly how far cellular edema correlates with parameters of the anaerobic energy turnover independent of the method used for cardiac arrest, and secondly to what extent cellular edema developing during reversible global ischemia is reduced after reperfusion. Canine hearts were arrested 1. by aortic cross clamping (ACC), 2. by coronary perfusion with St. Thomas solution, or 3. HTK (histidine tryptophan ketoglutarate) solution (Custodiol). Samples for biochemical and structural analysis were taken at different times during ischemia and after reperfusion with Tyrode solution. Cellular edema determined morphometrically and given as volume ratio of sarcoplasm and mitochondria to myofibrils (Vvsp + V vmi/Vvmf) varies significantly in the differently arrested hearts. Reperfusion after a decrease in ATP to 4 mumol/gww (revival time) leads to a nearly complete structural recovery. The relationship between cellular edema and defined over-all metabolite tissue concentrations and extracellular pHe values shows: 1. during the decrease of creatine phosphate to 3 mumol/gww, cellular edema does not change; it is, however, significantly higher after ACC and St. Thomas than after HTK perfusion; 2. at each lactate concentration, cellular edema differs significantly depending on the form of cardiac arrest; 3. during the decrease of ATP and pHe cellular edema increases and is comparable at concentrations < 4 mumol/gww and at pHe values < 6.5 independent of the form of cardiac arrest; 4. beyond 10 mumol/gww of inorganic phosphate (Pi), increasing values for cellular edema correspond to defined Pi values in the differently arrested hearts. Thus, the ratio VVSp+ VVMi/VVMf is a powerful parameter for the determination of cellular edema during ischemia, as well as for correlations with metabolic parameters.
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PMID:Cellular edema and alterations in metabolite content in the ischemic and reperfused canine heart following different forms of cardiac arrest. 912 37

The objective of this study was to assess the protective capacity of UW solution in comparison to Bretschneider's (HTK) cardioplegic solution under moderate hypothermic conditions (25 degrees C), as those usually present during intraoperative myocardial protection. Ischemia-induced alterations of cardiac function parameters were analyzed and compared for each solution after 45 min of ischemic storage and 60 min of reperfusion with oxygenated Krebs-Henseleit buffer (KHB), using a rat working-heart model. Compared to nonischemic values, left-ventricular systolic and diastolic pressure, +dp/dtmax and -dp/dtmax were significantly better maintained in the HTK (95 mm Hg, 7 mm Hg, 2,657 mm Hg/s and 2,122 mm Hg/s) than in the UW group (76 mm Hg, p < 0.05, 11 mm Hg, p < 0.05, 1,745 mm Hg/s, p < 0.05 and 1,600 mm Hg/s, p < 0.05). Concerning the myocardial contents of ATP, creatine phosphate and the energy charge, a minor decrease was observed after preservation in HTK compared to UW solution. The results of this study indicate superior myocardial protection with the use of HTK solution for protection of the heart at 25 degrees C compared to UW solution.
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PMID:HTK versus UW solution for myocardial protection during moderate hypothermia. 925 98

Warm ischemia is known to induce substantial damage to the liver parenchyma. With respect to clinical liver transplantation, the tolerance of the liver to warm ischemia and the preservation of these organs have not been studied in detail. In isolated reperfused pig livers we proceeded according to the following concept: Livers were subjected to 1 or 3 h of warm ischemia. Subsequently, these organs were preserved by either normothermic perfusion or cold storage (histidine-tryptophan-alpha-ketoglutarate, HTK) for 3 h each. After storage, liver function was assessed in a reperfusion circuit for another 3 h. Parameters under evaluation were bile flow, perfusion flow, oxygen consumption, enzyme release into the perfusate (creatine kinase, glutamic oxaloacetic transaminase (GOT), lactic dehydrogenase, and glutamic pyruvic transaminase), and histomorphology. Damage to the liver was lowest after warm ischemia of 1 h. The results after cold storage were superior to those after normothermic perfusion (GOT: 3.2 +/- 0.3 and 2.6 +/- 0.2 U/g liver; cumulative bile production: 14.7 +/- 2.1 and 9.4 +/- 1 ml, respectively; P < 0.05). In contrast, we found substantial damage at the end of reperfusion in livers undergoing 3 h of warm ischemia under both preservation techniques with severe hepatocellular pyknoses and essentially altered nonparenchymal cells. The results suggest that pig livers undergoing 1 h of warm ischemia and cold storage for 3 h with HTK solution may lead to functioning after transplantation.
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PMID:Preservation of pig liver allografts after warm ischemia: normothermic perfusion versus cold storage. 939 99

This study was designed to assess whether the protective effect of ischemic preconditioning can be adapted for myocardium undergoing 6 h of no-flow ischemia. Twelve isolated rat hearts were either perfused with oxygen-bicarbonated Krebs-Henseleit buffer in the Langendorff mode for 35 min (n=6), or perfused in the same way for 20 min, following 5 min of global normothermic ischemia and 100 min of buffer-perfusion (n=6). The 12 hearts were then preserved for 6 h in HTK solution at 4 degrees C, followed by 30 min of reperfusion. Recovery of cardiac function, metabolic activity and intracellular free calcium concentration were compared between the two groups. After 6 h ischemia, the hearts that underwent preconditioning showed better recovery of left ventricular developed pressure (P<0.01), a lower end-diastolic pressure level (P<0.05), less creatine kinase leakage and a lower calcium concentration. There was no statistical difference in the recovery rate of coronary flow and leakage rate of LDH between the two groups. In conclusion, this experiment demonstrates that ischemic preconditioning improved myocardial functional recovery after 6 h of hypothermic ischemic preservation in the isolated rat heart. Preconditioning might be a potential mechanism for preserving the heart against long-term ischemia/reperfusion injury.
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PMID:Cardioprotective efficacy of ischemic preconditioning on long-term myocardial ischemia. 946 84

We evaluated three cardioplegic solutions, Bretschneider's cardioplegic solution (HTK), St. Thomas' Hospital solution (STH) and the solution of the National Institutes of Health (NIH), a solution with added nitroglycerin and lidocaine, for their ability to minimize ischemia-reperfusion injury in a working rat heart model. After cardioplegic arrest at 4 degrees C and subsequent 45 min of ischemic storage at 25 degrees C the function recovery of hearts was examined during 1 h of normothermic crystalloid reperfusion using Krebs-Henseleit buffer as perfusion medium. We noted a significantly better preservation of the maximum (+dp/dt(max)) and minimum (-dp/dt(max)) velocity of pressure development and a significantly higher coronary flow with the use of HTK (2,657 mm Hg/s, 2,122 mm Hg/s, 17 ml/min) compared to STH (1,600 mm Hg/s, p < 0.05; 1,591 mm Hg/s, p<0.05; 11 ml/ min, p<0.05), and an intermediate level of preservation of hemodynamic parameters with NIH (2,149 mm Hg/s, 1,766 mm Hg/s, 12 ml/min). Concerning the cardiac output, however, no major difference was found between the HTK (41 ml/min), the STH (34 ml/min) and the NIH group (36 ml/min). The decay of the myocardial energy charge was significantly lower in both the HTK and the NIH group as compared with conservation in STH solution. Lactate was lowest in the HTK group, CK and LDH releases in the effusate remained lowest after HTK and NIH preservation. The data of this study suggest that HTK and NIH most perfectly reduce the impairment of myocardial function and provide better myocardial protection during ischemic arrest at 25 degrees C and superior recovery compared to STH solution.
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PMID:Comparison of the solutions of Bretschneider, St. Thomas' Hospital and the National Institutes of Health for cardioplegic protection during moderate hypothermic arrest. 970 50

The extent and distribution of myocardial edema induced by perfusion with cardioprotective solutions is of great interest. Domestic pig hearts (n = 12) were perfused in situ after aortic cross clamping either with Bretschneider's cardioplegic solution (HTK, 4 degrees C, n = 3), with a heparinized Krebs-Henseleit solution containing 30 mmol/L 2,3 Butanedionemonoxime (BDM, 4 degrees C, n = 3) or with heparinized pig blood (HPB, 24 degrees C, n = 3). After a three-hours storage period, magnetic resonance tomography (MRI) was carried out. The acquired T1-weighted data were used for the subsequent three-dimensional reconstruction based on the "Heidelberg ray-tracing technique". The small myocardial tissue blocks (n = 216) were excised from these hearts for dry weight measurements for 9 preselected regions in duplicate including ventricular papillary muscle, ventricular free wall, ventricular septum, apex, and atrial tissue. In control hearts (n = 3), dry weight was measured immediately after explantation (no MRI). The results of dry-weight measurements and three dimensional visualization were compared. Dry-weight measurements revealed that considerable myocardial edema is induced by any of the experimental procedures. The effects were most pronounced after BDM perfusion. Regardless how the edema was induced, there were significant differences of the water content within the heart: the water content in the heads of the papillary muscles and in the interventricular septum was always smaller than that of the free left- and right-ventricular walls. The heterogeneity of myocardial edema and its spatial distribution pattern could be qualitatively visualized. The experimental data (biophysical data and 3D visualization) clearly show a heterogeneity of myocardial edema induced by different types of cardioprotective solutions. As the presence of myocardial edema represents one of the crucial events in the pathophysiology of myocardial dysfunction occurring during myocardial infarction, ischemia, heart transplantation, and extracorporeal circulation, the present study represents an interesting contribution towards intravital detection and distribution of myocardial edema.
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PMID:Heterogeneity of myocardial edema in isolated pig hearts after perfusion with different types of cardioprotective solutions. 988 20

While post-transplant pancreatitis is still a frequently occurring complication of whole pancreas transplantation, dysfunction of the endocrine tissue is rarely observed. Given that microcirculatory disorders play a major role in the pathogenesis of pancreatitis, we hypothesized a dissociation of endocrine and exocrine microvascular control in pancreas transplantation (cold ischemia-reperfusion) and studied this dissociation quantitatively, analyzing the pancreatic microcirculation after heterotopic isogeneic pancreaticoduodenal transplantation in rats by means of fluorescence microscopy. Functional capillary density (FCD) of both exocrine and endocrine tissue of pancreatic grafts after 1 h of cold storage in HTK solution did not differ when compared to sham-operated, time-matched controls. Intermittent capillary perfusion, which is absent under sham control conditions and which is proposed to be operative as a compensatory mechanism to counteract malperfusion, was observed in 52% of the exocrine, but in only 8% of the endocrine, tissue studied (p < 0.05). In contrast, cold storage of pancreatic grafts for 6 h in HTK resulted in a complete loss of intermittent capillary perfusion in exocrine tissue and, consequently, marked exocrine perfusion failure (decrease in FCD), while FCD of pancreatic endocrine tissue was preserved without any significant change in the incidence of intermittent capillary perfusion. Thus, our results indicate a higher susceptibility of the exocrine pancreas to cold ischemia/reperfusion events that is associated with significant alterations in nutritive perfusion and, thus, with limitations of the oxygen supply to the tissue. This may lead to inflammatory tissue reactions in the clinical setting of pancreas transplantation.
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PMID:Exocrine, but not endocrine, tissue is susceptible to microvascular ischemia/reperfusion injury following pancreas transplantation in the rat. 1008 Apr 6

Eurocollins has almost been abandoned because of the glucose disadvantage. UW is certainly the most used preservation solution for livers, kidneys, and pancreases with excellent clinical and experimental preservation data. UW can certainly be considered the current golden standard solution. However, the disadvantage of high viscosity, high price, uneasy handling of many 1-L bags, and the fact that the radical scavenger glutathion cannot be detected in the bags by chemical analysis (presumably due to diffusion) encourage competitors to produce new compounds with better cost to effect ratios. HTK has a firm place in cardiac preservation; by demonstration of equal safety and efficacy in preserving livers and kidneys, at least in the middle and lower range of cold ischemia time, HTK will be sued more frequently, particularly with the consideration of lower price and more easy handling aspects. The suggested high volume perfusion is not really necessary, calculation based on a total volume of 10 L for a multiorgan donor show significant cost reductions. Celsior is current only used for cardiac preservation. Beyond all aspects of conservation and preservation potencies of all these fluids, it must not be forgotten that cold ischemia itself is a risk factor for organ function. Therefore, cold ischemia time should be kept as short as possible. People are willing to accept 24 hours or more cold ischemia time in kidney transplantation because organ failure can be treated by dialysis. In other organs, where immediate organ function is essential, like in clinical heart transplantation, cold ischemia is hardly ever extended beyond 6 hours. Why are hearts and kidneys so different? Very likely, there is no difference, and the outstanding results in living unrelated kidney transplants is mostly due to short cold ischemia time.
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PMID:Preservation solutions for transplantation. 1045 72

The quality of organ preservation is of major importance in minimizing the incidence of primary graft nonfunction and organ rejection. For this study a new semiquantitative score was developed that grades morphologic tissue alterations in the liver according to their frequency and severity. It was applied to assess commonly used perfusion solutions for their efficacy in preventing early and late tissue damage after rat liver transplantation. For transplantation the livers were stored in Euro-Collins (EC, group I; n = 11), histidine-tryptophan-alpha-ketoglutarate (HTK, group II; n = 11), or University of Wisconsin solution (UW, group III; n = 11). Rat liver transplantation was performed with graft arterialization by the method of Engemann. Biopsies were taken for morphological examination and semiquantitative scoring during the donor operation, after 4 h of cold storage, 1 h after reperfusion, and 4 weeks postoperatively. An immunohistological bromodeoxyuridine (BrdU) assay was also performed on the day of dissection to assess the rate of hepatic proliferation. Semiquantitative morphological analysis gave widely differing results in all experimental groups after 4 h of ischemia. There was less intracellular and interstitial edema, fatty degeneration, intralobular necrosis, and hepatocellular proliferation in the HTK group than in the other groups. Neither after cold ischemia nor 1 h after reperfusion did Kupffer-cell activation occur; this is known to play a major role in the development ofischemia and reperfusion injury. Furthermore, late changes such as bile-duct proliferation and vascular and sinusoidal alterations appeared less frequently in this group. The hepato-protective powers of HTK solution might therefore be due to decreased Kupffer-cell activation.
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PMID:Organ preservation with EC, HTK, and UW, solution in orthotopic rat liver transplantation. Part II. Morphological study. 1050 Oct 78


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