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Query: UMLS:C0599766 (functional recovery)
 13,441 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isolated perfused working rat hearts were subjected to elective cardiac arrest for 20 or 30 min. Various methods of arrest were studied, either singly or in combination and with or without coronary perfusion. The functional recovery of the heart following the termination of arrest was found to be related to the concentration of ATP and creatine phosphate in the myocardium at the end of the period of arrest. In turn, these concentrations were dependent upon the method used to induce arrest. Normothermic ischemic arrest led to a marked reduction in high energy phosphates and a poor functional recovery. In contrast, coronary perfusion with hypothermic solutions or solutions containing high concentrations of potassium, induced arrest without depleting ATP or creatine phosphate. These procedures conferred considerable protection on the myocardium and thus permitted good recoveries. The energy status and recovery associated with ischemic arrest could be improved by combining the ischemia with hypothermia or potassium arrest. The latter, while increasing recovery significantly, still failed to afford complete protection to the myocardium. Potassium chloride gave greater protection than potassium citrate. When topical hypothermia was combined with ischemia, a time and temperature relationship was demonstrated but effective protection could only be obtained with severe topical hypothermia over a relatively short time period. The results stress the importance of maintaining high energy phosphates during arrest, and this requires the provision of a continuous supply of oxygen and nutrient, which may perhaps be best achieved by ensuring continuous and adequate coronary perfusion.
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PMID:Ischemic damage and metabolism during elective cardiac arrest. 120 80

The effect of unilateral labyrinthectomy followed by the process of vestibular compensation on the incorporation of radioactive phosphate into frog brain proteins was investigated. Phosphoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. The present data show that unilateral labyrinthectomy affects the incorporation of 32P into various frog brain proteins. In particular, the phosphorylation of a 20-kDa protein appeared enhanced during early stages of vestibular compensation (4-12 days). This 20-kDa protein was shown to be immunologically related to myelin basic protein and its phosphorylation was regulated by an endogenous calcium/calmodulin-dependent protein kinase. These data might indicate that in addition to neuronal components, components of glial origin are also involved in biochemical events that lead to functional recovery after neuronal lesions.
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PMID:Vestibular compensation affects endogenous phosphorylation of frog brain proteins. 137 81

Repeated brief episodes of ischaemia "precondition" the myocardium and protect it during a subsequent period of sustained ischaemia. We subjected isolated rat hearts to sustained ischaemia with or without reperfusion after different schedules of preconditioning. We demonstrated that preconditioning with three 5 min periods of ischaemia separated by 10 min periods of reperfusion permits better functional recovery than preconditioning with three 2 min ischaemic periods separated by 10 min of reperfusion. Preconditioned hearts had creatine phosphate and adenine nucleotide levels comparable to those in the aerobically perfused controls, and showed good functional recovery. Although the mechanisms by which preconditioning protects the heart from subsequent ischaemic damage are unclear, we speculate that preservation of mitochondrial function and oxidative energy production is involved.
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PMID:Effects of duration of ischaemia during preconditioning on mechanical function, enzyme release and energy production in the isolated working rat heart. 143 17

Mechanisms and kinetics of the effects of the ionic composition of two different storage solutions, an intracellular type and an extracellular type, were analyzed by examining the myocardial functional and metabolic recovery processes during the early reperfusion periods after 3 hours of cold storage using an isolated perfused working rat heart model. The hearts were stored either in our own cardioplegic solution (group 1) or in Collins' solution (group 2) for 3 hours at 4 degrees C and were then reperfused. The electromechanical activity in group 1 was elevated, as indicated by a higher incidence of ventricular fibrillation at 5 minutes of reperfusion (group 1: 5/6; group 2: 0/5; p < 0.05). The coronary flow rate in group 2 was significantly lower, at least for the first 15 minutes after reperfusion, than that of group 1, suggesting the possible existence of vasoconstriction in group 2. Although myocardial oxygen uptake during this period was smaller in group 2, the recovery of myocardial high-energy phosphate levels was better and creatine kinase leakage was less in group 2. The recovery of aortic flow after 30 minutes of reperfusion was significantly better in group 2 (group 1, 59.1 +/- 5.8%; group 2, 71.7 +/- 6.0%; p < 0.01), although the early recovery was somewhat worse in group 2. These data suggest that the heart stored in an intracellular-type solution, compared with one stored in an extracellular-type solution, recovers in an electromechanically suppressed fashion during the early reperfusion phase, associated with a better metabolic recovery and a slower but larger functional recovery. The disadvantage of the intracellular-type solution, however, may be its effect on the increase of coronary vascular resistance during the early reperfusion period.
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PMID:The myocardial recovery mode after cold storage for transplantation with Collins' solution and cardioplegic solution. A functional and metabolic study in the rat heart. 143 13

A significant reduction in the extent of cell necrosis or the incidence of reperfusion-induced arrhythmias can be achieved with ischaemic preconditioning. If preconditioning was also found to be effective in protecting against global ischaemia, then this may have significant implications for the preservation of the heart during cardiac surgery. We therefore investigated this phenomenon in relation to recovery of contractile function after global ischaemia in the isolated rat heart. Isolated working rat hearts (n = 6 per group) were perfused aerobically at 37 degrees C for 20 min and contractile function recorded. This was followed by 10 min of aerobic Langendorff perfusion (control hearts) or 5 min global ischaemia (37 degrees C) + 5 min Langendorff reperfusion (preconditioned hearts). The hearts were then subjected to 10, 15, 20 or 25 min of global ischaemia (37 degrees C) and reperfusion (15 min Langendorff + 20 min working) after which function was again assessed. Preconditioning improved functional recovery after all durations of ischaemia. Thus aortic flow after 10, 15, 20 and 25 min of ischaemia and 35 min of reperfusion recovered to 84, 58, 16 and 5%, respectively, in controls and 88, 74, 55 and 20%, respectively, in the preconditioned groups. To assess whether preconditioning was effective in a surgically relevant model of hypothermic ischaemia, the experiments were repeated with longer periods (45, 70, 90, 115, 135 and 160 min) of ischaemia at 20 degrees C. Under these conditions, normothermic preconditioning increase the post-ischaemic recovery of aortic flow after 115, 135 and 160 min of ischaemic (from 36, 20 and 10%, respectively, in controls to 57, 39 and 26%, respectively, in preconditioned hearts). There was no consistent correlation between tissue high energy phosphate content and enhanced post-ischaemic recovery. Thus, we have demonstrated that ischaemic preconditioning can improve contractile function after global ischaemia in the isolated rat heart, we have defined the duration of ischaemia for which it is operative, and we have shown that this protection is additive to that of hypothermia-induced protection during ischaemia. This may have clinical implications for cardiac surgery.
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PMID:Ischaemic preconditioning and contractile function: studies with normothermic and hypothermic global ischaemia. 147 13

Depletion of high-energy phosphates, accumulation of inorganic phosphate and intracellular acidosis have each been proposed as important events in the transition from reversible to irreversible ischemic injury. To assess whether each variable is predictive of functional recovery on reperfusion, these were measured in the isolated isovolumic rat heart using 31P NMR. Perfused hearts were subjected to either 10, 12 or 40 min of normothermic ischemia followed by 40 min of reperfusion. Hearts were then freeze-clamped for further analysis of phosphate metabolites by NMR and ion chromatography. High-energy phosphates, Pi, phosphomonoesters and pH were measured by 31P NMR spectroscopy at 2 minute intervals. Heart rate and developed pressure were monitored simultaneously. All hearts undergoing 10 min of ischemia and 40% of hearts subjected to 12 min of ischemia demonstrated good functional recovery. The remainder of hearts ischemic for 12 min went into contracture on reperfusion with little return of function. Hearts subject to 40 min of ischemia went into ischemic contracture and showed no recovery on reperfusion. Intracellular pH, [ATP], and [Pi] measured prior to reperfusion did not predict the extent of recovery. However, phosphomonoesters were detected prior to reperfusion in all hearts that did not recover well, but were not observed in hearts that showed good mechanical recovery. Analysis of tissue extracts by 31P NMR and ion chromatography indicated that the most prominent components of the phosphomonoesters were glucose 6-phosphate, alpha-glycerol phosphate and AMP. In conclusion, of the various phosphorus metabolites that can be measured by 31P NMR, only one group, the phosphomonoesters, was predictive of functional recovery.
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PMID:Predicting functional recovery from ischemia in the rat myocardium. 148 87

It was examined whether lactate influences postischaemic hemodynamic recovery as a function of the duration of ischaemia and whether changes in high-energy phosphate metabolism under ischaemic and reperfused conditions could be held responsible for impairment of cardiac function. To this end, isolated working rat hearts were perfused with either glucose (11 mM), glucose (11 mM) plus lactate (5 mM) or glucose (11 mM) plus pyruvate (5 mM). The extent of ischaemic injury was varied by changing the intervals of ischaemia, i.e. 15, 30 and 45 min. Perfusion by lactate evoked marked depression of functional recovery after 30 min of ischaemia. Perfusion by pyruvate resulted in marked decline of cardiac function after 45 min of ischaemia, while in glucose perfused hearts hemodynamic performance was still recovered to some extent after 45 min of ischaemia. Hence, lactate accelerates postischaemic hemodynamic impairment compared to glucose and pyruvate. The marked decline in functional recovery of the lactate perfused hearts cannot be ascribed to the extent of degradation of high-energy phosphates during ischaemia as compared to glucose and pyruvate perfused hearts. Glycolytic ATP formation (evaluated by the rate of lactate production) can neither be responsible for loss of cardiac function in the lactate perfused hearts. Moreover, failure of reenergization during reperfusion, the amount of nucleosides and oxypurines lost or the level of high-energy phosphates at the end of reperfusion cannot explain lactate-induced impairment. Alternatively, the accumulation of endogenous lactate may have contributed to ischaemic damage in the lactate perfused hearts after 30 min of ischaemia as it was higher in the lactate than in the glucose or pyruvate perfused hearts. It cannot be excluded that possible beneficial effects of the elevated glycolytic ATP formation during 15 to 30 min of ischaemia in the lactate perfused hearts are counterbalanced by the detrimental effects of lactate accumulation.
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PMID:The nucleotide metabolism in lactate perfused hearts under ischaemic and reperfused conditions. 148 52

We have compared the protective properties of three cardioplegic solutions (St. Thomas' Hospital, University of Wisconsin, and Bretschneider) for the long-term hypothermic preservation of the rat heart. Hearts (n = 8 per group) were excised and arrested by an infusion (10 ml at 4 degrees C) of cardioplegic solution. After 4, 6, or 8 hours of storage at 4 degrees C, they were reperfused in the Langendorff mode for 15 minutes and then in the working mode for 20 minutes. After 4 hours of storage, postischemic cardiac output in the St. Thomas' and Wisconsin groups was 68.8 +/- 4.6 and 63.7 +/- 3.0 ml/min, respectively (NS); nonischemic aerobic control cardiac output was 83.2 +/- 2.6 ml/min. In the Bretschneider group, cardiac output was only 43.4 +/- 3.6 ml/min (p less than 0.05 compared to the other groups). Extending storage to 6 or 8 hours led to further decreases in recovery of function in all groups (cardiac output in the St. Thomas' and Wisconsin groups was 53.7 +/- 3.2 and 52.2 +/- 5.1 ml/min after 6 hours and 39.9 +/- 2.2 and 45.8 +/- 2.5 ml/min after 8 hours, respectively; NS). With the Bretschneider solution the cardiac output was again lower (37.6 +/- 3.0 and 22.3 +/- 4.1 ml/min, respectively). Creatine kinase leakage tended to be greater in the Bretschneider group, but adenosine triphosphate and creatine phosphate contents were well preserved in all groups. In further studies, hearts (n = 8 per group) were infused with the three solutions and stored at 4 degrees C for 8 or 10 hours; they were then heterotopically transplanted into the abdomens of homozygous recipients. After 24 hours of reperfusion, the hearts were excised and taken for ex vivo functional and metabolic studies. Recovery of contractile function was similar in all groups, but the tissue content of adenosine triphosphate tended to be greater in the St. Thomas' and Wisconsin groups (15.0 +/- 1.5 and 14.7 +/- 1.0 mumol/gm dry weight in the 8-hour storage groups and 12.1 +/- 1.2 and 11.7 +/- 0.8 mumol/gm dry weight in the 10-hour storage groups, respectively) than in the Bretschneider groups (12.3 +/- 0.9 and 9.1 +/- 1.6 mumol/gm dry weight, respectively). Creatine phosphate content recovered completely in all groups. We conclude that all three solutions afford similar protection to the hypothermically stored rat heart, but that the St. Thomas' Hospital and University of Wisconsin solutions are marginally superior to the Bretschneider solution.
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PMID:Long-term hypothermic storage of the mammalian heart for transplantation: a comparison of three cardioplegic solutions. 149 25

To investigate the effect of adenosine on anoxic damage of brain tissue, energy metabolism in relation to neural activity was studied using hippocampal slices from the guinea-pig. For the index of energy metabolism, adenosine triphosphate and creatine phosphate in each slice were measured and also postsynaptic potentials (population spike potentials) were recorded in the granule cell layer of the slices. After preparation of the slices, one group of slices was incubated for 120 min in standard medium and another in the medium containing adenosine (5 mM). The adenosine triphosphate content of the former group was 8.8 mmol/kg protein whereas that of the latter was 15.8 mmol/kg protein. During deprivation of oxygen and glucose, adenosine triphosphate and creatine phosphate in the control slices and the slices treated with adenosine decreased rapidly. Adenosine did not alter the rate of consumption of high energy phosphates in both slices. The pretreatment of slices with adenosine (5 mM), however, considerably enhanced the recovery of the adenosine triphosphate level during reoxygenation with glucose after deprivation of oxygen and glucose for 15 and 30 min. Postsynaptic potentials in the granule cell layer of the slice were recorded before and after 10, 15, 20 or 25 min deprivation of oxygen and glucose in the control slice and the slices pretreated with adenosine (5 mM) for 60 min. In the control slices, postsynaptic potentials in one of 10 slices could be recorded after 60 min reoxygenation following 15 min anoxia/aglycemia, while postsynaptic potentials in 10 of 15 slices treated with adenosine could be detected even after 15 min of anoxia/aglycemia. Thus the functional recovery of postsynaptic potentials agreed well with the results of the recovery of adenosine triphosphate level in the slices treated with adenosine. These results indicate that adenosine has a protective effect against anoxic/aglycemic damage of brain tissue by facilitating the resynthesis of tissue adenosine triphosphate during the recovery period.
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PMID:Protective effect of adenosine on the anoxic damage of hippocampal slice. 154 8

We have investigated the reported ability of aspartate to enhance greatly the cardioprotective properties of the St. Thomas' Hospital cardioplegic solution after prolonged hypothermic storage. Rat hearts (n = 8 per group) were excised and subjected to immediate arrest with St. Thomas' Hospital cardioplegic solution (2 minutes at 4 degrees C) with or without addition of monosodium aspartate (20 mmol/L). The hearts were then immersed in the same solution for 8 hours (4 degrees C) before heterotopic transplantation into the abdomen of homozygous rats and reperfusion in vivo for 24 hours. The hearts were then excised and perfused in the Langendorff mode (20 minutes). Addition of aspartate to St. Thomas' Hospital cardioplegic solution gave a small but significant improvement in left ventricular developed pressure, which recovered to 82 +/- 3 mm Hg compared with 70 +/- 2 mm Hg in control hearts (p less than 0.05). However, coronary flow and high-energy phosphate content were similar in both groups. In subsequent experiments hearts (n = 8 per group) were excised, arrested (2 minutes at 4 degrees C) with St. Thomas' Hospital cardioplegic solution containing a 0, 5, 10, 20, 30, 40, or 50 mmol/L concentration of aspartate, stored for 8 hours at 4 degrees C, and then reperfused for 35 minutes. A bell-shaped dose-response curve was obtained, with maximum recovery in the 20 mmol/L aspartate group (cardiac output, 48 +/- 5 ml/min versus 32 +/- 5 ml/min in the aspartate-free control group; p less than 0.05). However, additional experiments showed that a comparable improvement could be achieved simply by increasing the sodium concentration of St. Thomas' Hospital cardioplegic solution by 20 mmol/L. Similarly, if sodium aspartate (20 mmol/L) was added and the sodium content of the St. Thomas' Hospital cardioplegic solution reduced by 20 mmol/L, no significant protection was observed when recovery was compared with that of unmodified St. Thomas' Hospital cardioplegic solution alone. In still further studies, hearts (n = 8 per group) were perfused in the working mode at either high (greater than 80 ml/min) or low (less than 50 ml/min) left atrial filling rates. Under these conditions, if functional recovery was expressed as a percentage of preischemic function, artifactually high recoveries could be obtained in the low-filling-rate group. In conclusion, assessment of the protective properties of organic additives to cardioplegic solutions requires careful consideration of (1) the consequences of coincident changes in ionic composition and (2) the characteristics of the model used for assessment.
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PMID:Effect of sodium aspartate on the recovery of the rat heart from long-term hypothermic storage. 154 51


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