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

These studies demonstrate the presence of an immunosuppressive and cytotoxic factor in the perfusate of ischemic damaged liver. A BDE rat liver perfusate (LP) was prepared after 6 h warm ischemia by intraportal perfusion with 2 ml/g of Ringer's solution (one time-LP1 or five times-LP5 with the same volume of solution). Protein amount of LP1 and LP5 was 0.9 and 2.8-3.9 mg/ml. In vivo activity of the hepatic perfusates was studied by effect on renal allograft survival time. LEW rats with BDE kidney transplant, treated daily with 2 ml of LP1 for 5 days, starting on the day of grafting, survived 8.9 +/- 1.8 days, significantly longer than control animals (6.5 +/- 0.5 days). After administration of LP5 renal recipients survived 10.3 +/- 1.3 days and when the treatment with LP5 was prolonged to 10 days animals survived 9-34 days (mean 15.3 +/- 7.3 days). The presence of the suppressive factor was also studied in renal, spleen and heart extracts, prepared after 6 h warm ischemia. Protein amount of extracts was adjusted to 3-4 mg/ml by Ringer's solution. Immunosuppressive activity of LP and other organ extracts was tested in vitro by their influence on MLC reaction (LEW and BDE lymphocytes) and on LEW cells in the PHA stimulation assay. Lymphocyte blastogenic response on MLC reaction and in culture with PHA was strongly inhibited by LP but weakly by organ extracts. Hepatic perfusates were cytotoxic against lymphocytes and fibroblasts in a three day cultures. Cytotoxic activity of the organ extracts was lower than LP. Extract of the cold preserved kidneys showed immunosuppressive and cytotoxic effect like extract of ischemically injured kidneys but smaller than LP. After heat inactivation at 70 degrees C the activity of hepatic perfusate decreased. Immunosuppressive organ factor (IOF) seems to be a normal cell component, not a decomposition product of the ischemically damaged hepatic tissue.
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PMID:[Immunosuppressive and cytotoxic effect of the humoral factors from ischemic damaged organs (author's transl)]. 645 30

Intracellular enzyme activities can be greatly influenced by alterations of pH, and non-physiologic pH may inhibit cell metabolism. The study was undertaken to examine the influence of pH values in preservation solution on ischemic tolerance time of the liver. BDE rat livers were used. Livers were preserved for 20 min or 2 h in warm ischemia after an initial perfusion with Ringer's solution at pH 9.0, 7.4, and 6.0. The values of total adenine nucleotide (TAN) and energy reserve (ER) in the livers were determined at the end of the preservation. After 20 min of warm ischemia, TAN values at pH 9.0 and 7.4 fell to 2.727 +/- 0.255 and 2.410 +/- 0.164 mumol/g, respectively (normal values: 3.414 +/- 0.270 mumol/g) and ER values to 0.786 +/- 0.186 mumol/g at pH 9.0 and to 0.446 +/- 0.095 mumol/g at pH 7.4 (normal values: 2.962 +/- 0.214 mumol/g). A similar trend was also observed after 2 h of warm ischemia. The preservation with a solution at pH 6.0 did not present any difference as compared to that at pH 7.4. Four-hour preservation in cold ischemia with Ringer's solution at pH 9.0 rendered higher values of TAN (2.635 +/- 0.085 mumol/g) and ER (0.336 +/- 0.026 mumol/g) than those in preservation at pH 7.4. No significant difference between TAN and ER values was found when 4-h preservation at pH 7.4 and 6.0 was compared. In another group an intermittent liver perfusion at 1-h interval was performed with chilled Ringer's solution; afterwards GOT, GPT, beta-glucuronidase, and acid phosphatase values in the effluents were evaluated. All of these enzymes showed higher concentration in the effluent with solution at pH 7.4 than that at 9.0. These results suggested that better intracellular energy reserve and organ viability can be maintained by preservation with alkaline solution. Furthermore, ER values seemed to be an excellent indicator of the organ viability during preservation. These were also confirmed by orthotopic hepatic transplantation in pigs. Livers were successfully preserved with alkaline Ringer's solution for up to 12 h. However, without change of pH, livers could not be preserved for more than 4.5 h.
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PMID:[Prolongation of ischemic tolerance time of donor livers by alkaline preservation solutions]. 647 1

Although few surgeons dispute the benefits of high-potassium crystalloid cardioplegia, objective comparison of the efficacy of various formulations is difficult in clinical practice. We compared four commonly used cardioplegic solutions in the isolated rat heart (N = 6 for each solution) subjected to 180 minutes of hypothermic (20 degrees C) ischemic arrest with multidose cardioplegia (3 minutes every half-hour). The clinical solutions studied were St. Thomas' Hospital solution, Tyers' solution, lactated Ringer's solution with added potassium, and a balanced saline solution with glucose and potassium. Postischemic recovery of function was expressed as a percentage of preischemic control values. Release of creatine kinase during reperfusion was measured as an additional index of protection. St. Thomas' Hospital solution provided almost complete recovery of all indexes of cardiac function following ischemia including 88.1 +/- 1.6% recovery of aortic flow, compared with poor recovery for the Tyers', lactated Ringer's, and balanced saline solutions (20.6 +/- 6.5%, 12.5 +/- 6.4%, and 9.6 +/- 4.2%, respectively) (p less than 0.001). Spontaneous defibrillation was rapid (less than 1 minute) and complete (100%) in all hearts in the St. Thomas' Hospital solution group, but much less satisfactory with the other formulations. Finally, St. Thomas' Hospital solution had a low postischemic level of creatine kinase leakage, contrasting with significantly higher enzyme release in the other solutions tested (p less than 0.001). Although differences in composition are subtle, all potassium crystalloid cardioplegic solutions are not alike in the myocardial protection they provide. Comparative studies under controlled conditions are important to define which formulation is superior for clinical application.
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PMID:Comparison of the protective properties of four clinical crystalloid cardioplegic solutions in the rat heart. 647 50

Twenty-five patients undergoing aortic valve replacement were administered two different electrolyte solutions pre- and intraoperatively: patients in group A (n = 9) received a balanced solution of electrolytes and trace metals with aspartate as anion (Inzolen), patients in group B (n = 16) received Ringer's solution with potassium chloride referenced to frequently-measured serum potassium levels. From the left ventricular apex region, needle biopsies were obtained at three points in time: 1. beginning of CPB, 2. end of ischemia, 3. after ten minutes of reperfusion. The tissue samples were enzymatically analyzed for the content of ATP, CP, ADP and lactate. In group A (patients with aspartate) ATP (moderately) and CP (markedly) decreased after ischemia with a marked increase after reperfusion. ADP and lactate in this group (A) increased at the end of ischemia and decreased after reperfusion. ATP and CP in group B (KCl) showed a similar course during the investigation. Lactate (markedly) and ADP (moderately) increased after ischemia without changing after reperfusion. Mean values of ATP and CP in group A were significantly higher than those of group B at all times. Mean values of ADP and lactate, however, in group A were below those of group B. The data indicate an improvement in energetic metabolism of myocardium in man. The results point out the possible importance of aspartates in compound with electrolytes and trace metals in preservation of biochemical energy.
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PMID:[Effect of aspartate compounds on the biochemical characteristics of myocardial energy metabolism in man]. 666 81

The presence of lactic acidosis in the cerebrospinal fluid of patients suffering brain injury as the result of trauma, subarachnoid hemorrhage, neoplasia, or ischemia has been well documented. The authors theorized that this acidosis becomes harmful in itself, and that treatment with an alkalinizing agent (tris(hydroxymethyl)aminomethane: tromethamine) capable of penetrating the blood-brain barrier would be efficacious. Fifteen pairs of mongrel cats were subjected to a 2.85-atmosphere fluid-percussion injury (LD80), and were supported by respirators for up to 72 hours prior to being placed in cages for an additional 4 days of observation. Experimental cats underwent continuous infusion of tromethamine (begun 10 minutes after injury); control animals were infused with an equal volume of lactated Ringer's solution. Twenty percent of the control group survived until sacrificed on Day 7 post-injury. Survival in the tromethamine group was 60% (p less than 0.05), and morbidity also appeared to be reduced in the treated cats. Intracranial pressure (ICP) in treated cats was 60% (p less than 0.05) of that in the control cats after respirator support for 3 days. Tromethamine infusion was associated with improved survival, decreased morbidity, and decreased ICP when compared with results in control animals. The literature with regard to central nervous system acidosis has been reviewed in an attempt to clarify and define this problem.
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PMID:Experimental brain injury: successful therapy with the weak base, tromethamine. With an overview of CNS acidosis. 671 65

To determine whether the calcium antagonist verapamil can produce satisfactory myocardial preservation during global ischemia, we studied three groups of eight dogs. Serial left ventricular biopsy specimens were taken for adenosine triphosphate and creatine phosphate content. Arterial and coronary sinus blood samples were obtained for lactate and oxygen content determination prior to ischemia, immediately after the ischemic interval, and after a 30 minute reperfusion period. Starling and isovolumetric ventricular function curves were determined prior to ischemic arrest and after 45 minutes of reperfusion. All animals were systemically cooled to 25 degrees C, and the aorta was clamped for 120 minutes. Group I had a potassium cardioplegic solution (30 mEq/L) chilled to 4 degrees C and injected into the aortic root. The initial dose was 200 ml and an additional 100 ml was infused at 20 minute intervals. Group II had a solution containing verapamil (0.15 mg/kg/L), diluted in Ringer's solution (4 degrees C), injected into the aortic root. The initial and subsequent doses were as in Group I. Group III received the same solution as Group II, but at room temperature. Alterations in lactate metabolism were not significantly different in any of the three treatment groups. A reduction in oxygen consumption was seen in Group III, but was not found to be statistically significant. However, the reduction in coronary flow at the end of reperfusion was statistically significant in Group III (p less than 0.05). Verapamil given at room temperature resulted in poor preservation of left ventricular function and high-energy stores. Verapamil combined with extreme hypothermia (Group II) provided excellent preservation of left ventricular compliance and contractility. Cold verapamil cardioplegia was superior to potassium cardioplegia for the preservation of adenosine triphosphate.
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PMID:Verapamil cardioplegia: improved myocardial preservation during global ischemia. 673 3

The hypothesis tested was that the composition of the prime and the perfusate at the time of reperfusion had an influence on postischemic cardiac performance. Twelve dogs in two equal groups had long (210 +/- 10 minutes) hypothermic (25 degrees +/- 1 degree C) perfusions. Each had 180 minutes of global ischemia and were given 500 ml of the same cold (4 degrees C) cardioplegic solution (CPS) every 45 minutes and topical hypothermia with a resultant average myocardial temperature of 10 degrees +/- 2 degrees C. Group A had a prime (1,958 ml) consisting of a 50/50 mixture of 5% dextrose in water and 5% dextrose in Ringer's injection to which mannitol (12.5 gm), furosemide (20 mg), and heparin (6,000 units) were added. Group B received a prime (1,868 ml) of 5% dextrose in Ringer's injection (1 L) and 750 ml of 6% helastarch in normal saline to which NaHCO3 (10 mEq), furosemide (20 mg), mannitol (25 gm), and heparin (6,000 units) were added. During perfusion, Group A received lactated Ringer's solution and Group B received a 1 : 2 portions of Ringer's injection and 6% helastarch. Additionally, Group B received additional furosemide and mannitol 5 minutes prior to the reperfusion interval. The results showed a marked difference between groups in postischemic cardiac recovery 120 minutes after cessation of cardiopulmonary bypass. The Group B dogs had statistically (less than 0.02) greater cardiac output, stroke volumes, and stroke work index at equal preloads and lower total peripheral resistances. Arterial systolic, diastolic, and mean pressures and right atrial pressures were not different. The Group A dogs required nearly threefold the volume of fluid additions required during bypass and twice the amount of NaHCO3 as Group B dogs. It is concluded that the composition of the prime and fluids used during bypass and use of agents to counteract tissue water accumulation during the ischemic and reperfusion intervals strongly influences postischemic cardiac performance. Further, these data suggest that the composition of the perfusate may have a greater influence on the functional recovery of the heart than the composition of various CPSs.
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PMID:Adequacy of the perfusate: its influence on successful myocardial protection. 713 9

In Wistar rats thermocontrolled normothermic ischemia of the whole body was induced 20 min after i.p. injection of 300 mg piridoxilate (Glyco-6) per kg body weight or Ringer's solution in a control group. Piridoxilate pretreatment did not influence the amount of total adenine nucleotide loss in 30 min of normothermic ischemia of forebrain, skeletal muscle, liver or kidney but resulted in a significantly higher loss in myocardium and lung. A positive effect on the conversation of energy rich substances was found only in the skeletal muscle (creatine phosphate content). Significant effects on substrates of glycolysis were found only in myocardium and lung but in the myocardium also a higher accumulation of lactate occurred.
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PMID:[Influence of piridoxilate on the energy metabolism of normothermic ischemic organs in the rat]. 719 75

The management of patients with both polycythemia and limb-threatening ischemia presents many difficulties because in this population, vascular surgical procedures carry a particularly high incidence of hemorrhagic and thromboembolic complications. We evaluated the use of acute isovolemic hemodilution in 12 polycythemic patients who required urgent surgery due to severe ischemia and threatened limb loss. Within 48 hours, blood was withdrawn in units of 500 ml and simultaneously replaced with 1,500 ml of lactated Ringer's solution until a hematocrit of 35 to 40 percent was achieved. After hemodilution, two patients had such a marked improvement that no further therapeutic measures were required immediately. Four patients showed definite improvement in pulmonary vascular resistance tracings and segmental Doppler pressures, but ischemia was not fully ameliorated. These patients together with the remaining six patients underwent vascular surgery within 1 to 14 days after hemodilution. A hematocrit of 32 to 40 percent was maintained during the perioperative period. All arterial reconstructions were successfully completed and there were no perioperative failures. No pulmonary emboli, myocardial infarctions, or deaths occurred in this period. These results indicate that in polycythemic patients, urgent vascular surgery can be performed more safely with the concomitant use of acute isovolemic hemodilution.
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PMID:Use of isovolemic hemodilution in the management of arterial ischemia in patients with polycythemia. 725 33

The enhancement of blood flow in experimental skin flaps following postischemic perfusion washout was investigated in rats. Unilateral island skin flaps based on the superficial epigastric vessels were raised and subjected to 6 hr of primary ischemia. Group 1 was designated as a control and did not undergo postischemic perfusion washout. In the remaining rats, postischemic washout was performed with one of five agents: Group 2--lactated Ringer's solution; Group 3--University of Wisconsin solution, an organ preservation medium; Group 4--verapamil, a calcium channel blocker; Group 5--urokinase, a thrombolytic agent; Group 6--iloprost, a stable prostacyclin analog. Two hours following perfusion washout, fluorometric analysis revealed a statistically significant enhancement of blood flow in Groups 4, 5, and 6, compared to Groups 2 and 3 (p < 0.05). Furthermore, a significant increase in skin surface fluorescence was demonstrated in all the flaps that underwent perfusion washout, compared to the control flaps (p < 0.05). By analyzing skin surface fluorescence, the enhancement of nutritive blood flow in flaps, following postischemic perfusion washout, was evaluated. This is the first study in which the above pharmacologic agents were compared in a quantitative manner.
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PMID:Enhancement of fluorescein perfusion in experimental skin flaps following postischemic washout with iloprost, urokinase, verapamil, and University of Wisconsin solution. 750 90


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