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

70 rats were subjected to tourniquet ischemia of a hind limb for a period of two and three hours. 12 rats served as controls. After release of the 3 hours tourniquets 20 rats were treated either with Ringer's solution or with hydroxyethyl starch. Kidney function and morphology, systolic blood pressure, hematocrit, serum electrolytes, creatinine and urea were studied as different times of recirculation. 1. Reduction in renal function was only observed after releasing the tourniquets. 2. The extent of reduction in renal function depended on the time of ischemia and time of recirculation. 3 hours of tourniquet with two hours of recirculation led to the largest extent of reduction in renal function and renal parenchymal lesions. 3. If the infusion of HES was applied at the beginning of recirculation, reduction in renal function was prevented, as well as parenchymal lesions. Ringer's infusion, however, did not improve kidney function to a normal range.
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PMID:[Animal experimental studies on partial kidney function after temporary tourniquet ischemia with and without blood substitute therapy]. 3 60

Abdominal aortic aneurysmectomy is being performed with progressively lower operative mortality and morbidity. Three hundred thirty seven patients have had elective aneurysm repair since 1954. Factors affecting mortality and morbidity in the last 108 cases are analyzed. Seventy-four per cent of patients had pre-existing disease, either cardiac, pulmonary, renal, cerebrovascular, diabetes mellitus, or hypertension. Six patients died following operation, a mortality rate of 5.5%. One died of pulmonary and 5 of cardiac causes. No patient died of renal failure or required dialysis. A signficant feature of management is the regimen of fluid therapy using dextrose in lactated Ringer's solution during and after operation to minimize hypotensive and renal complications. No patient developed a wound infection, graft infection, wound dehiscence, stroke, or intestinal ischemia. Serious postoperative complications were largely cardiac or pulmonary. Despite recent liberalization of indications for operation, comparative figures show continued reduction in operative mortality from 17% during 1954-1961, or 7.4% during 1962-1967, to 5.5% in the 1968-1974 era. This declining mortality is related to earlier diagnosis using non-invasive methods (sonogram), simplified operative techniques, improvement in fluid management, innovations in cardiopulmonary therapy, and recognition and proper handling of unusual manifestations of aortic aneurysms.
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PMID:Surgical management of abdominal aortic aneurysms: factors influencing mortality and morbidity--a 20-year experience. 12 60

Numerous methods have been used in an attempt to prevent myocardial injury that results from the interruption of aortic flow during cardiac operations. The authors describe a relatively simple means of inducing cardioplegia during coronary bypass surgery by coronary perfusion with cold lactated Ringer's solution through the aortic root. When the results following the employment of hypothermic coronary perfusion for intraoperative cardioplegia were compared with those obtained without its use, the procedure was found to confer a degree of intraoperative myocardial protection and appeared to lead to a decrease in intraoperative myocardial infarction, subendocardial ischemia and intraoperative mortality.
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PMID:Hypothermic coronary perfusion for myocardial protection during aortocoronary bypass. 30 79

Twenty-four pigs were studied to assess the effect of potassium in a cardioplegic solution on the ability of the swine myocardium to maintain functional and metabolic integrity following induced ischemia. The pigs were evaluated on total and right heart bypass with measurement at normothermia and after a one-hour intervention of stroke volume (SV), coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and lactate extraction. Myocardial tissue gases (PmO2 and PmCO2) were continuously monitored and, at the conclusion of the procedure tissues were analyzed for adenosine triphosphate (ATP). There were five interventions: (1) hypothermic perfusion (28 degrees C) (Group 1); (2) hypothermic ischemia (28 degrees C) (Group 2); and hypothermic ischemia with a cardioplegic solution (nonlactated Ringer's solution, pH 7.4, 4 degrees C) using (3) normokalemia (4 mEq of potassium chloride/L, 300 mOsm/L (Group 3), (4) hyperkalemia (43 mEq of KCl/L, 390 mOsm/L) (Group 4), and (5) normokalemia with increased osmolarity (3.6 mEq of KCl/L, 400 mOsm/L) (Groups 5). A significant decrease in SV and elevation in peak PmCO2 were seen in all groups subjected to ischemia except those protected with hyperkalemic solution. We conclude that the presence of hyperkalemia in a cold root perfusion solution provides better myocardial protection than cold root perfusion alone. Furthermore, potassium arrest appears to be more protective than coronary perfusion at 28 degrees C.
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PMID:The importance of hyperkalemia in a cold perfusion solution: a correlative study examining myocardial function, metabolism, tissue gases, and substrates. 48 29

Pressor amine therapy in circulatory shock has been generally unfavorable, presumably because these drugs produce unselective, intense vasoconstriction and curtail rather than improve true capillary inflow, distribution and outflow in the microcirculation. The present study compares the influence of a new analog of vasopressin, [2-phenylalanine, 8-ornithine]vasopressin (POV), over wide dose ranges and Ringer's solution on: 1) survival after circulatory shock, induced by different means (e.g., hemorrhage, bowel ischemia); 2) blood pressure and hematocrit in shocked animals; and 3) various microcirculatory parameters after induction of hemorrhage and bowel ischemia shock (e.g., lumen diameters of various types of microvessels, reactivity of microvessels, microvascular flow patterns, leukocytic sticking, petechial hemorrhage formations, vasomotion, etc.). Local administration of POV, in contrast to constrictor catecholamines, induces a venular-to-arteriolar profile of constrictor activity in the normal rat mesenteric microcirculation. Systemic administration of POV to rats subjected to either lethal hemorrhage or bowel ischemia shock: 1) increases survival rates 2- to 8-fold over control rats receiving Ringer's solution; 2) produces a plateau-like effect on arterial blood pressure and returns arterial hematocrits toward normal after hemorrhage; and 3) regenerates and sustains vasomotion and venular tone, decreases microvascular hyper-reactivity characteristic of shock syndromes, restores constricted arteriolar lumen sizes toward normal, predisposes to a splanchnic microbed virtually free of stasis and petechiae, and restores capillary perfusion and outflow to near-normal. These findings indicate that it is possible to synthesize vasoactive molecules which exert selective microvascular effects and are highly beneficial in therapy of low-flow states.
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PMID:Microcirculatory approach to the treatment of circulatory shock with a new analog of vasopressin, (2-phenylalanine, 8-ornithine)vasopressin. 93 6

Recent animal studies have suggested that there exists an activated subpopulation of circulating granulocytes which plays an important part in microvascular sequestration and tissue injury during shock and ischemia. In this respect, spontaneous granulocyte activation in form of pseudopod formation, a manifestation of actin polymerization, is a high risk for microvascular entrapment. The present investigation was carried out to determine if there is a significant difference in pseudopod formation in vitro between granulocytes obtained from healthy volunteers without symptoms and patients with acute cardiovascular illnesses. Blood samples from 25 healthy volunteers, 12 patients with acute myocardial infarction (AMI) and 12 patients with acute cerebral infarction (ACI) to determine spontaneous pseudopod formation in granulocytes with a high resolution light microscope over a period of several hours. The results revealed that the mean percentage of cells with pseudopod formation in the control group was below 10% in the first 3 hours, and increased to about 50% at 12 hours. In AMI patients, the level of activation within the first hour was not significantly different from the controls, but it rose rapidly to 90% in 4 to 5 hours. Patients with cerebral infarction, however, showed no significant difference from the control group. When the granulocytes of healthy subjects were incubated in plasma of AMI, the cells were activated similar to AMI granulocytes in their own plasma. When AMI plasma was serially diluted with Ringer's solution, the activation curve fell successively. These results indicate that AMI patients' blood contains plasma factor(s) which can activate granulocytes at a more rapid rate than controls.
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PMID:Spontaneous activation of circulating granulocytes in patients with acute myocardial and cerebral diseases. 130 82

Dopamine has been demonstrated to be involved in the development of ischemic neuronal damage in the striatum. This detrimental effect of dopamine may involve activation of second messenger systems, such as the cyclic AMP (cAMP) cascade, which may enhance the susceptibility of striatal neurons to ischemia. In the present study, we have evaluated the relationship between ischemia-induced changes in cAMP and dopamine neurotransmission. Microdialysis probes were implanted in both striata, and a D1 antagonist (SCH-23390, 100 microM) was administered through one probe and modified Ringer's solution through the other. After a stabilization period, rats (n = 6) were subjected to 20 min of ischemia by two-vessel occlusion plus hypotension. Extracellular samples were collected from both striata, before, during, and after ischemia, and analyzed for cAMP by radioimmunoassay. Ischemia induced a significant increase in extracellular cAMP (means +/- SE, fmol/microliter; baseline: 4.35 +/- 1.1, ischemia: 12.2 +/- 1.98), which was also observed at 4 h of recirculation (mean level of 8.45 +/- 1.14). Treatment with the D1 antagonist significantly inhibited the rise in extracellular cAMP during ischemia and recirculation. These results indicate that an ischemia-induced surge in dopamine and activation of D1 receptors are involved in the generation of cAMP during ischemia and recirculation. Because activation of the adenylate cyclase cascade may modulate the effects of glutamate, generation of cAMP through this pathway may play a role in facilitating the injurious effects of dopamine during ischemia.
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PMID:Ischemia-induced changes in extracellular levels of striatal cyclic AMP: role of dopamine neurotransmission. 132 27

The influence of ischemia and reperfusion on nucleotide concentration in human myocardium was investigated during heart and heart-lung transplantation. Myocardial preservation during heart transplantation was achieved by infusion of cold St. Thomas' Hospital cardioplegic solution followed by storage in Ringer's solution at 4 degrees C during transport. In contrast, the hearts of heart and lung donors were preserved by core cooling using cardiopulmonary bypass and infusion of cold blood cardioplegia containing 26 mM potassium. The heart-lung block was transported in cold donor blood. Nucleotides and their catabolite concentrations were measured in donor tissue specimens taken before organ collection, before commencement of implantation and 30 min after aortic clamp removal. During reperfusion, samples of coronary sinus and arterial blood were collected and analysed for nucleotide catabolite concentration. Myocardial ATP and total nucleotide pool remained almost unchanged during the ischemic transport of the donor organs with only very small increases in myocardial inosine and hypoxanthine concentrations. However, a significant decrease of total adenine nucleotide pool by 10%-20% was demonstrated between the start of implantation and 30 min post-reperfusion. A release of inosine + hypoxanthine was greatest in the 1st minute (15-25 microM), but was still substantial after 10 min of reperfusion (5-15 microM). Metabolic changes tended to be more pronounced during heart-lung transplantation than during heart transplantation.
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PMID:Adenine nucleotide catabolism in human myocardium during heart and heart-lung transplantation. 154 98

Extracellular free radicals were detected in rat striatal perfusate samples by intracerebral microdialysis coupled to the spin trapping technique. Five Sprague-Dawley rats were subjected to 30 min of global ischemia followed by reperfusion; throughout the experimental period the intrastriatal dialysing probe was perfused with Ringer's solution containing the spin trap agent pyridyl-N-oxide-t-butylnitrone (100 mM) together with the iron chelating agent diethylentriaminepentacetic acid (100 microM). A radical adduct occurred during ischemia and early reperfusion, but not in basal conditions; the spin adduct was characterized as a carbon centered radical, consistent with the presence of an oxidative attack on membrane lipids. The direct evidence of the formation of free radicals supports the hypothesis that free radicals play a role in the pathogenesis of the histological damage during brain ischemia.
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PMID:Detection of free radicals during brain ischemia and reperfusion by spin trapping and microdialysis. 160 39

The effects of increased intra-abdominal pressure (IAP) on intestinal blood flow were studied in eight anesthetized pigs. Mesenteric artery blood flow (MABF), intestinal mucosal blood flow (IMBP), tonometric intramucosal pH (pHi), mean BP (MAP), cardiac output (CO), and pulmonary artery wedge pressure (PAWP) were measured as IAP was raised to 10, 20, 30, and 40 mm Hg by infusing lactated Ringer's solution (LR) into the peritoneal cavity. The MAP was kept constant with IV LR. Cardiac output fell slightly from 5.4 +/- 1.1 at baseline to 4.0 +/- 1.2 L/min at an IAP of 40 mm Hg (p less than 0.05). An IAP of 20 mm Hg caused significant decreases in MABF (73% +/- 22% of baseline) (p less than 0.05) and IMBF (61% + 12% of baseline) (p less than 0.05). These changes became progressively greater as the IAP was increased to 40 mm Hg. The pHi fell to 6.98 +/- 0.14 at 40 mm Hg IAP (p less than 0.01), indicating severe mucosal ischemia. Thus increased IAP can cause severe intestinal ischemia, which may be more important than the cardiac, pulmonary, and renal changes usually described.
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PMID:Effect of increased intra-abdominal pressure on mesenteric arterial and intestinal mucosal blood flow. 163 5


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