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

The local effects and radiographic efficacy of four water-soluble contrast media, barium and saline were evaluated in 91 anesthetized rats with a ligature applied to the anterior mesenteric artery and vein via laparotomy. The rats were observed for 8 hours after instillation of 3 mL of test substance via oro-gastric tube. Radiographs were taken after 1, 4 and 8 hours of observation. After 8 hours, the intestines were weighed, a biopsy was done for light microscopy, and blood and urine were sampled for testing. The roentgen contrast media caused dehydration and increased influx of fluid into the small bowel lumen in proportion to their osmolality. They diluted the bowel contents, enhanced their progression and distended the bowel walls. The diagnostic qualities of radiographic films were better using the new, low-osmolal contrast media than using either barium or sodium diatrizoate. The water-soluble contrast media were excreted in the urine, as demonstrated by dense opacification of the urinary bladder on abdominal films, and increased iodine concentrations at x-ray fluorescence analysis of the urine. This may be useful clinically in detecting bowel ischemia.
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PMID:Water-soluble contrast media compared with barium in enteric follow-through. Urinary excretion and radiographic efficacy in rats with intestinal ischemia. 340 8

In addition to radionuclide ventriculography and thallium scintigraphy, already well established in nuclear medicine, assessment of myocardial metabolism is also of interest for diagnosis and follow-up observations in heart disease. Under aerobic conditions and in the fasting state, the heart muscle primarily oxidizes fatty acids; during ischemia, in contrast, there is slowing of fatty acid turnover and increased anaerobic glycolysis. With 11C-palmitic acid, in humans, reduced fatty acid uptake has been documented in infarcted myocardial regions. The analysis of 11C-palmitic acid in dogs showed a three-phased elimination curve in normal myocardium. In ischemic myocardium, there was diminished utilization of free fatty acids and the glucose utilization was concomitantly increased. After insulin-glucose infusion, as well, there was increased glucose utilization and a reduction in fatty acid utilization. Studies with 11C-palmitic acid require the equipment for positron emission tomography (PET); because of the short half-life of 20.3 minutes, the nuclide must be generated by a cyclotron in the immediate vicinity. In the search for well-suited isotopes for use in planar scintigraphy employing a gamma camera, the uptake and elimination of a variety of isotopically-marked fatty acids were measured and compared with the characteristics of 14C-palmitic acid. For 17-123I-heptadecanic acid (IHA) the elimination curve was similar to that of 14C-palmitate: disadvantage, however, was the relatively high percentage of water soluble marked catabolites which required dual parameter analysis by means of 99-m-technetium pertechnetate or 123I sodium iodide to quantify the amount of myocardial fatty acid utilization through subtraction of the externally measured water soluble catabolite from the externally measured total activity. In studies with the gamma camera in fasting patients in whom 2 to 3 mCi IHA was injected intravenously after symptom limited bicycle ergometry, in healthy subjects the elimination halftime for the first rapid phase was 24.4 +/- 4.7 minutes. Patients with angiographically-documented coronary artery disease, in the afflicted myocardial segments, had diminished fatty acid uptake and prolonged elimination halftime as compared with normally perfused segments. In patients with dilated cardiomyopathy there was an inhomogeneous distribution of activity in the myocardium and, in contrast to coronary artery disease, a discordance between local fatty acid uptake and turnover rate. After chronic and acute alcohol consumption there were comparable findings which were shown to be reversible after several weeks of abstinence.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Planar scintigraphy versus PET in measuring fatty acid metabolism of the heart]. 349 62

A case is reported in which death followed translumbar aortography. The onset of acute ischemia of the lower limbs without thrombosis and of diffuse skin mottling below the level of the puncture are unusual features. These suggest the responsibility of the iodine hydrosoluble contrast medium in the genesis of this lethal complication whose mechanisms are discussed.
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PMID:[Severe complication of translumbar aortography. Apropos of a case]. 631 23

Fatty acids were analyzed by a new method which involved their isolation from hexane extracts of serum or brain tissue in aqueous potassium hydroxide (10 microliter) and methylation directly in this solution with methyl iodide. The resulting fatty acid methyl esters were partitioned into ethylene chloride (25 microliter) and were quantitated by gas-liquid chromatography. The procedure was documented by comparison with conventional methylation reactions on serum fatty acids. This method, which avoids thin-layer chromatography and which measures individual free fatty acid concentrations in 20-mg brain tissue samples, should be of particular value for examining regional free fatty acids in brain following ischemia and trauma.
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PMID:A new procedure to analyze free fatty acids. Application to 20-mg brain tissue samples. 648 Jul 72

Electrocardiographic monitoring of 406 patients undergoing intravenous urography was performed before, during, and after the examination. Major cardiac arrhythmias and ischemia were encountered frequently (18%) in those with cardiac disease but also occurred (5%) in the healthy individual with no history of heart disease. Rapid higher dose (28-g iodine) bolus injections result in more cardiac alterations than the slower but larger (42-g iodine) infusion method, whereas the smaller (14-g iodine) bolus injections have the least cardiac effect. Ectopic ventricular beats, the most common abnormality, are usually transient but remain the most potentially lethal of the effects of intravenous contrast media on the heart.
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PMID:Cardiovascular radiology. Cardiac alterations during intravenous urography. 720 29

Acute lesions of the gastroduodenal mucosa may result from gastric mucosal ischemia with subsequent cellular dysfunction, capillary leakage and increased susceptibility to mucosal damage. A new technique for measuring the effect of hypovolemic shock and gastric mucosal permeability is presented. Piglets were injected intravenously with human serum albumin labelled with 100 micro Ci of iodine-131 (131I-HSA). Serial blood and gastric samples were obtained for gamma counting during the control, hypovolemic shock and resuscitative periods. Increased gastric acid secretion and clearance of labelled serum albumin occurred after resuscitation from hypovolemic shock. The authors believe that increased capillary permeability and defective gastric mucosal cell function due to ischemia contribute to these changes.
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PMID:Radiotracer assessment of gastric mucosal permeability after hypovolemic shock. 736 60

Fibroblast viability of the allograft valve leaflet has been suggested to affect clinical durability. Warm ischemic time is thought to be one of the critical determinants of cell viability. We assessed cell viability of allograft valves by flow cytometry, using a fluorescein diacetate-propidium iodide stain to characterize the effects of warm ischemia and cryopreservation on viability. Twelve human pulmonary valves with harvest-related warm ischemic times (range, 70 to 520 minutes; mean +/- standard deviation, 225 +/- 157 minutes) were studied by flow cytometry. We assessed cell viability of the allograft valve leaflets before and 30 days after storage. A significant negative correlation was found between warm ischemic time (x minutes) and cell viability (y%) before (y = -0.024x + 96.7; r2 = 0.62; p = 0.002) and after 30 days of storage (y = -0.036x + 94.0; r2 = 0.86; p = 0.001). Cell viability of the cryopreserved allograft valves was well preserved (> 70%) with a warm ischemic time less than 520 minutes (8.7 hours).
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PMID:Effect of warm ischemia and cryopreservation on cell viability of human allograft valves. 764 40

The goal of this work was to define the distinction between irreversible structural changes and actual loss of cell viability during hypoxic/ischemic/reperfusion injury to one-day cultured adult rabbit cardiac myocytes. Myocytes were exposed to 5 mM NaCN and 20 mM 2-deoxyglucose (chemical hypoxia) or anoxia at pH 6.2 to simulate ischemia. Shortening and hypercontraction (cell rounding and blebbing) were monitored by bright field microscopy, and loss of viability was determined by nuclear labeling with propidium iodide. After both treatments, myocytes began to shorten after 30 minutes, and most were hypercontracted after 3 hours. 50% loss of viability did not occur until after 6 hours or more. To simulate reperfusion, myocytes were washed with fresh aerobic buffer at pH 7.4. Loss of viability was accelerated when cells were reperfused with Krebs-Ringer solution. This cell killing was prevented when myocytes were reperfused with nutrient culture medium instead of Krebs-Ringer solution. Both contracted and hypercontracted cells partially relaxed after reperfusion. These results indicate that structural changes (contraction, hypercontraction and blebbing) to adult cardiac myocytes are distinct from outright cell death caused by plasma membrane failure. Persistence of cell viability suggests that rescue of cardiac myocytes from necrotic cell death may be possible even very late in injury.
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PMID:Changes in shape and viability of cultured adult rabbit cardiac myocytes during ischemia/reperfusion injury. 771 3

Polymorphonuclear neutrophils (PMNs) have been implicated in microvascular injury following ischemia and reperfusion (I/R) but the relative contribution of obstruction versus toxic mediators is not well defined. Therefore, the present study was performed to determine the contribution of exogenous or endogenous activation on PMN-induced microvascular and hepatocyte injury. Rat livers were isolated and perfused at constant pressure with Krebs buffer with red cells (Hct-10%) and monitored for perfused sinusoids (PS) and dead hepatocytes (propidium iodide-stained, DH) by intravital microscopy. PMNs isolated from the peritoneum after oyster glycogen injection were added to the perfusate either without or with activation by phorbol myristate acetate (PMA, 160 nM). Unactivated PMNs stuck in the liver but had no significant effect on either perfused sinusoids (11.1 +/- .4/field, unactivated PMNs versus 11.9 +/- .5/field, the time-matched control) or dead hepatocytes (1.2 +/- .4/field, unactivated PMNs versus 1 +/- .3/field, the time-matched control). Infusion of PMA-activated PMNs resulted in significant decrease in perfused sinusoids and increase in DH (9.5 +/- .3/field for PS and 3.2 +/- .6/field for DH, respectively). In contrast, when PMNs were "activated" by infusion into a liver previously made ischemic for 30 min, DH were significantly increased after 60 min (26.2 +/- 4.5/field, I/R plus PMNs versus 12.4 +/- 2/field, I/R only) but perfused sinusoids were not different from ischemia alone. These results demonstrate that oxidatively quiescent PMNs do not cause cellular or microvascular injury in spite of microvascular accumulation. Activated PMNs damage microcirculation or hepatocytes depending on the nature of the activation.
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PMID:Effect of activation on neutrophil-induced hepatic microvascular injury in isolated rat liver. 773 61

The contribution of microcirculatory failure to ischemia/reperfusion injury in isolated perfused rat livers was investigated using intravital epifluorescence videomicroscopy. The degree of microvascular shut-down during reperfusion was modulated by the reperfusion conditions: flow-controlled (10 ml/min), in which microcirculatory failure is minimized by maintenance of constant flow through the liver, and pressure-controlled, in which microvascular shut-down is allowed to occur. Livers underwent 60 min of ischemia, 90 min of ischemia, or no ischemia (control). Perfused sinusoids and dead hepatocytes were quantified in 10 standardized microscopic fields (9000 microns2) per liver during off-line video playback. With flow-controlled reperfusion, microvascular (sinusoid) shut-down was largely avoided; a maximum of 21% of the sinusoids failed to conduct flow. Pressure-controlled reperfusion, however, resulted in early and severe shut-down. A significant decrease of approximately 20-30% was found after 60 min of ischemia and 30 min of reperfusion, while, after 90-min ischemia and 90-min reperfusion, 90% of the sinusoids failed to conduct flow. The appearance of dead hepatocytes correlated well with the number of perfused sinusoids (r = -0.78 for flow controlled, r = -0.97 for pressure-controlled). Only an occasional dead hepatocyte was observed with control perfusion, while up to 50% stained with propidium iodide following 90-min ischemia and 90-min reperfusion under pressure-controlled conditions. These results indicate that loss of sinusoidal flow can be ameliorated by flow-controlled reperfusion; moreover, hepatocyte necrosis during reperfusion is highly dependent upon the integrity of the microcirculation.
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PMID:Microcirculatory failure determines lethal hepatocyte injury in ischemic/reperfused rat livers. 774 24


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