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

Hemorrhage to a mean arterial pressure of 41 mm. Hg in ten dogs decreased Heidenhain pouch blood flow to 6 ml. per minute and aminopyrine clearance to 0.93 ml. per minute. Pouch oxygen consumption fell from 1.47 to 0.74 ml./min.-100 Gm. and total body oxygen consumption remained unchanged. Net ion fluxes during shock and reinfusion did not change significantly from control values of minus 89.8 muGq./30 min.-100 cm.-2 for H-+ and 88.6 muEq./30 min.-100 cm-2 for Na-+. However, PD decreased from 54 to 24 mv. in parallel with a fall in net Cl-minus flux from 56.8 to minus 11.7 muEq./30 min.-100 cm-2. Nine of ten pouches subjected to shock and instilled acid test solution (ATS) developed superficial mucosal erosions. No ulcerations were found in either seven control dogs (anesthesia + ATS) or in three dogs subjected to shock without ATS. Acid appears to be of prime importance in the production of stress ulcers during or following ischemia, even though there is no increase in mucosal ionic permeability.
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PMID:The role of acid and ischemia in production of stress ulcers during canine hemorrhagic shock. 23 95

Sixteen healthy, active men were studied to determine the effects of severe arterial hypoxemia on the electrocardiograms during exercise. The electrocardiograms were all normal at maximum heart rate while the subject breathed ambient air. During maximal exercise breathing ten percent oxygen (mean arterial oxygen pressure [Po2] of 31 mm Hg), only one of the 16 had ST segment changes suggestive of ischemia. These were not present on a repeated study. The widely held view that systemic hypoxemia causes ischemic changes on the electrocardiogram was not confirmed in this study.
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PMID:The effects of acute severe arterial hypoxemia on the electrocardiogram during exercise. 23 94

31P NMR was used to continuously monitor ATP and inorganic phosphate levels in perfused mouse liver. Under "optimal" conditions, the time resolution of the technique was approximately 1 min. In the absence of any metabolic perturbations the ATP level remained constant for at least 2 hr and decreased by only approximately 20% in 18 hr. Both ATP and inorganic phosphate levels responded to alterations in the oxygen supply to the liver. The half-time for this response was approximately 1 min, and the response to short periods of hypoxia or ischemia was partially reversible. The addition of insulin caused only a minor decrease in the ATP level but significantly decreased the rate of response of ATP and phosphate levels to hypoxia and ischemia.
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PMID:Rapid ATP assays in perfused mouse liver by 31P NMR. 29 54

In rabbits a tourniquet shock was produced by 4-hour unilateral ischemia of one hind leg. By measuring the tissue oxygen tension on the surface of the ischemically damaged muscle, the liver and kidney the regional rate of perfusion of these organs in the state of shock was investigated. Additionally morphological examinations of muscle, liver, kidney and heart were carried out. In therapeutic trials with a proteinase inhibitor (Trasylol), prednisolone and streptokinase, Trasylol proved to prolong the time of survival significantly.
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PMID:[The pathophysiology of tourniquet shock]. 31 60

Time-compressed Fourier analysis of the electroencephalogram has proven to be a useful analytical procedure during anesthesia and surgery which simplifies data interpretation by presenting the EEG in a time-compressed frequency domain rather than the conventional time domain. This method of data analysis graphically accentuates the electroencephalographic correlates of ischemia-induced cerebral dysfunction and other cerebral oxygen consumption abnormalities. The ability to accentuate trends in frequency and power is derived from sequential plotting of spectra to produce a graph with three dimensional axes of frequency, time, and power. In carotid endarterectomies the system has proven more useful than the conventional EEG in assessing the need for a vascular shunt to maintain internal carotid flow during endarterectomy. In open-heart surgery time-compressed EEG spectral analysis has allowed early recognition of cerebral ischemia resulting from arterial hypotension and venous hypertension. Five cases are presented which demonstrate the ability of our system to reflect developing cerebral ischemia.
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PMID:Monitoring of cerebral perfusion during anesthesia by time-compressed Fourier analysis of the electroencephalogram. 32 37

Canine kidneys (n = 17) were flushed with COLLINS (C2), SACKS II, LAMBOTTE (KMgS), ROSS (hypertonic citrate), or RINGER glucose-mannitol solution following a 30-min period of normothermic ischemia. After 24 h hypothermic preservation with retrograde oxygen persufflation (ROP) and autotransplantation, the immediate functional recovery was determined using inulin and PAH clearance methods and compared with the normal contralateral kidney. While a good functional recovery was found in the COLLINS group, significantly exceeding results from hypothermic ischemic storage preservation, in experiments using other flush solutions ROP preservation resulted in only a small immediate function. Thus the experiments indicate that COLLINS solution C2 is the optimal flush solution for ROP preservation.
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PMID:[Hypothermic storage under aerobic conditions--the effect of different flushing solutions on kidney functional recovery]. 37 90

Myoglobin is the oxygen-binding protein characteristic of skeletal and cardiac muscle. With muscle disease or dysfunction, myoglobin may enter the circulation, and after renal clearance, it may also appear in the urine. Therefore, the presence of myoglobinemia and myoglobinuria may serve as indicators of the presence and severity of muscle disease. With newly developed methods of detection, myoglobinemia and myoglobinuria are now recognized as complications of trauma, ischemia, surgery, states of exertion and stress, metabolic abnormalities, inherited enzyme disorders, toxin and drug actions, and inflammatory states. Infarction of the heart muscle also can be detected by myoglobin assay. Persistent myoglobinuric states may be complicated by renal failure and electrolyte imbalance. The diagnosis of myoglobinemia and myoglobinuria can be now confirmed with the use of immunoassay techniques. Although not yet widely available, they offer the possibility of the specificity and sensitivity needed for clinical use.
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PMID:Myoglobin: methods and diagnostic uses. 40 72

The exposed left superior frontal gyrus of the anesthetized macaque brain was focally traumatized by a jet of compressed air. Focal blood flow in tissue around the lesion and total cerebral blood flow was determined before and during the 4 hours after trauma by the hydrogen clearance technique. Blood flow fell in tissue adjacent to the injured brain but the reduction was not statistically significant. Total cerebral blood flow, blood flow in the right superior-frontal gyrus, and oxygen consumption of the brain was unaffected by the trauma. The authors conclude that neither spreading ischemia within uninjured tissue surrounding focally traumatized brain nor posttraumatic diaschisis is readily provoked in the anesthetized brain of the monkey.
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PMID:Blood flow and oxygen consumption of the focally traumatized monkey brain. 40 66

In this series of experiments changes in oxygen diffusion coefficients were measured in waking primates undergoing focal middle cerebral artery ischemia; Ligation of the middle cerebral artery followed by a decrease of the oxygen diffusion coefficient in the areas supplied by that vessel to levels ten to twenty per cent below normal by twenty-five minutes following onset of ischemia. Following release and re-perfusion diffusion coefficient gradually increases and reaches a super normal peak value three hours after release of ligation. This is followed by a gradual reduction in diffusion coefficient with stabilization at preocclusion levels. In the three experiments described these changes following re-perfusion corresponded with clinical improvement of the neurological status of the monkeys;
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PMID:Effects of ischemia on the oxygen diffusion coefficients in the brain cortex (studies on Macaca irus). 41 26

Experiments were conducted in anesthetized open-chest dogs subjected to occlusion of the left anterior descending coronary artery for three hours. The oxygenation of myocardial tissue was monitored by a polarographic technique capable of recording simultaneously the oxygen tension (Po2) of myocardial tissue and electrograms. Ischemic injury was monitored by means of ST-segment elevations on myocardial and epicardial electrograms. The volume of the myocardial infarct was measured at the end of each experiment by incubation of transverse slices of left ventricle in a solution of nitroblue tetrazolium and by separation of the unstained (ischemic) from the stained (normal) portions. In one group of dogs, hemodilution was performed after 15 minutes of ischemia by exchanging blood with a stroma-free hemoglobin solution (from a hematocrit reading of 45 +/- 3 percent to 23 +/- 2 percent). Changes occurring in this group were compared with those occurring in dogs that did not undergo hemodilution, underwent hemodilution with dextran 75, or were transfused with whole blood. Hemodilution with hemoglobin reduced aortic and left ventricular filling pressures while increasing coronary blood flow, increased myocardial Po2 from 2 +/- 2 mm Hg to 8 +/- 2 mm Hg (P less than 0.005), lowered the ST-segment elevation of both myocardial and epicardial electrograms, and reduced the volume of the myocardial infarct. These effects were unmatched by hemodilution with dextran or infusion of whole blood.
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PMID:Improved oxygenation of ischemic myocardium by hemodilution with stroma-free hemoglobin solution. 42 81


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