Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a 45 year old male patient with a history of previous inferior myocardial infarction and unstable angina pectoris, coronary angiography revealed two-vessel disease: a 60-70% lesion in the middle third of the LAD, and a 90% lesion in the middle third of the very large RCA. There was only a small akinetic segment in the posterobasal region of the left ventricle. During angiography total occlusion of the RCA occurred followed the clinical and electrocardiographic signs of impending inferior reinfarction. Recanalization of the occluded vessel was accomplished by using a guide-wire, which was passed through a Sones catheter, placed in the RCA. The patient's symptoms subsided and the electrocardiographic signs of acute ischemia reverted within eight minutes. Aortocoronary bypass surgery with revascularization of the LAD and RCA was performed within 3 hours after recanalization. Postoperatively there was no evidence of major tissue loss by enzyme or electrocardiographic criteria. Control angiography, performed on the ninth day postoperatively, revealed the graft to the RCA to be widely patent. Left ventricular function was unchanged. It is concluded, that the combined approach of early transluminal recanalization of the acutely occluded RCA followed by successful construction of a graft to this vessel, has averted necrosis of a major portion of the left ventricle. However, general use of this technique does not seem advisable at the present time.
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PMID:Acute coronary occlusion with impending infarction as an angiographic complication relieved by a guide-wire recanalization. 31 53

The ability of prostacyclin (PGI2) to alter responses to acute myocardial ischemia was studied in open-chest, anesthetized cats. PGI2 was infused intravenously at 0.5 nmoles kg-1 min-1 in cats subjected to 5 h of myocardial ischemia by occlusion of the LAD coronary artery, and in sham-operated controls. GI2 infusion resulted in significantly decreased arterial blood pressure and inhibition of platelet aggregation. Coronary ligation resulted in significant S-T segment elevations lasting 5 h in vehicle-treated animals but only 1 h in cats with myocardial ischemia and receiving PGI2. At 5 h, cats with ischemia and given the vehicle showed S-T segment elevations significantly greater than the other two groups. Ischemic myocardium from vehicle-treated animals exhibited significantly less creatine phosphokinase (CPK) specific activity than normal tissue from the same hearts or myocardial tissue from the other two groups. This loss of CPK from ischemic myocardium of the cats given vehicle was reflected in plasma CPK specific activities which were significantly greater than those of sham-operated cats. The cats with ischemia and treated with PGI2 exhibited lower plasma CPK activities. These changes were moderated by PGI2 infusion during myocardial ischemia. PGI2 infusion may protect the ischemic myocardium by reducing oxygen demand, primarily through reductions in cardiac work, and by perhaps inhibiting platelet aggregation and preserving myocardial cell integrity.
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PMID:Studies on the protective effect of prostacyclin in acute myocardial ischemia. 46 18

To establish the effect of local and remote myocardial ischemia on interventricular septal motion, 27 open-chest dogs were studied using ultrasound and radioactive microspheres. In 14 dogs the left anterior descending coronary artery was ligated. If the ultrasound beam traversed ischemic septum (proximal LAD occlusion), significant (P less than 0.05) declines in systolic septal velocity (26.4 +/- 2.9 to 6.4 +/- 1.8 mm/sec), and excursion (2.6 +/- 0.3 to 0.7 +/- 0.2 mm) occurred, and systolic thickening was reduced. Similar significant changes were seen when the ultrasound beam traversed nonischemic septum adjacent to the ischemic area (distal LAD occlusion). In 13 additional dogs, circumflex coronary ligation produced posterior ischemia. The mean septal velocity for this group increased significantly (21.8 +/- 2.6 to 26.5 +/- 3.3 mm/sec), as did the septal excursion (2.5 +/- 0.2 to 3.1 +/- 0.4 mm). We conclude that acute LAD occlusion causes a reduction in systolic velocity, excursion, and thickening of both the involved ischemic and the adjacent nonischemic septum. When myocardial ischemia was produced in a part of the ventricle remote from the septum, septal velocity and excursion increased.
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PMID:Effects of acute coronary occlusion on the motion and perfusion of the normal and ischemic interventricular septum. 99 8

An improved dog model to study the effect of drugs on myocardial metabolism during ischemia is described. A reproducible degree of ischemia could be obtained by partial occlusion of the anterior descending branch of the left coronary artery (LAD), using an inflatable cuff with a micrometer. The possibility of inducing the stenosis twice in the same animal has the advantage that the animal can be used as its own control. The reproducibility of the degree of ischemia was demonstrated by the nonsignificant differences in local venous lactate, inorganic phosphate, and glucose concentrations after the first and second stenosis. The mean pressure difference over the stenosis was used to express the degree of coronary artery narrowing. In this model, one does not have to rely on the collateral circulation in collecting local venous blood. Moreover, it is very likely that this blood is obtained from the most pronounced ischemic area, which was localized with radioactive microspheres. At this degree of stenosis, left ventricular function was not affected too much, as was demonstrated by the slight changes in dP/dt max, and systolic and diastolic aortic pressure after induction of the stenosis. The usefulness of our model to evaluate the activity of drugs is demonstrated by the effect of fentanyl, a potent morphine-like analgesic, on the poststenotic local venous lactate and inorganic phosphate concentrations.
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PMID:An improved animal model for studying the effect of drugs on myocardial metabolism during ischemia. 120 87

To evaluate the efficacy of stress Tc-99m MIBI myocardial perfusion imaging using intravenous dipyridamole in detecting coronary artery disease (CAD) and to determine if chest pain symptom is a proper index for detection of myocardial ischemia in post-infarction patients, we observed 73 cases (65 men, 8 women, 38-79 years old) between Sept. 1990 and May 1992. All patients were suffered from old myocardial infarction (MI) evidenced by history and ECG and were divided into two groups: group I involving 41 patients with post-infarction chest pain symptom and group II including 32 patients without post-infarction chest pain symptom. Among them, 19 (group IA) of group I and 11 (group IIA) of group II received coronary arteriography (CAG) for comparison. Of the 41 group I post-infarction chest pain patients, 17 suffered from old anterior or antero-septal wall (AW) MI, 21 from old inferior wall (IW) MI, 1 from old lateral wall (LW) MI and 2 from combined old AW and IW (AIW) MI by ECG. All 17 patients with AWMI suffered from AW perfusion defect (7 were MI, 10 were MI with ischemia) but 7 of them from multivessel disease (MVD) by Tc-99m MIBI. All 21 patients with IWMI suffered from IW perfusion defect (9 were MI, 12 were MI with ischemia) but 13 of them from MVD by Tc-99m MIBI. Of the patient with LWMI and 2 patients with AIWMI suffered from MVD by Tc-99m MIBI. Of the 32 group II post-infarction patients without chest pain symptom, 12 suffered from old AWMI, 14 from old IWMI, 2 from old LWMI, 3 from AIWMI and 1 from ALWMI by ECG. Of the 12 patients with AWMI, 11 suffered from AW perfusion defect (6 were MI, 5 were MI with ischemia) but 1 of them from MVD by TC-99m MIBI. All 14 patients with IWMI suffered from IW perfusion defect (12 were MI, 2 were MI with ischemia) but 4 of them from MVD by Tc-99m MIBI. Of the 2 patients with LWMI suffered from LW infarction by Tc-99m MIBI. Of the 3 patients with AIWMI and 1 with ALWMI suffered from MVD by Tc-99m MIBI. Of the 11 patients in group IA and 5 patients in group IIA with AWMI, CAG revealed the incidence of infarct-related recanalization of LAD was 9/11(82%) and 4/5(80%) respectively and the respective incidence of MVD was 6/11(55%) and 0/5(0%).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Dipyridamole Tc-99m MIBI myocardial perfusion scintigraphy in patients with post-infarction chest pain symptom]. 129 41

Recent studies indicate that preconditioning of a heart by repeated stunning protects it from subsequent ischemic injury. Such myocardial preservation is likely to be due to adaptive modification of lipid composition and dynamic structure of cellular membrane. To test this hypothesis, swine heart was subjected to four episodes of 5 min stunning by LAD occlusion, followed by 10 min of reperfusion after each stunning. Heart was then made regionally ischemic for 60 min by LAD occlusion, followed by 6 h reperfusion. Control heart was perfused for 60 min, followed by 60 min ischemia and 6 h reperfusion. Free fatty acids (FFA) accumulated in control heart during ischemia as expected, which was further enhanced by reperfusion. The FFA level was also enhanced during ischemia in stunned myocardium. However, this FFA level was almost restored during reperfusion. The levels of polyunsaturated fatty acids (PUFA) such as oleate, linoleate, and arachidonate followed a similar pattern. Membrane fluidity, monitored by fluorescence polarization, was decreased during ischemia and reperfusion in the unstunned heart, with the corresponding increase in microviscosity. The increased microviscosity was significantly reduced by stunning. Since FFA are presumably generated from membrane phospholipids, these results suggest that stunning may cause the incorporation of a greater proportion of PUFA in membrane phospholipids, leading to preservation of membrane phospholipids and maintaining the membrane fluidity, which may be at least partially responsible for the attenuation of ischemic reperfusion injury.
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PMID:Preconditioning of heart by repeated stunning: adaptive modification of myocardial lipid membrane. 130 29

A series of 30 patients (25 males, 5 females, age = 28-73 years) with a clinical indication of thallium-201 stress/4 hours redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium-99m teboroxime (CARDIOTEC, Squibb Diagnostics) in order to assess the clinical usefulness of this new molecule and to compare it to thallium. In all cases coronary artery disease was known or highly suspected, with a history of myocardial infarction in 18 cases (subacute n = 6, remote n = 12) and/or previous by-pass surgery or PTCA in 5 cases. Medical treatment was not discontinued at the time of stress testing. Coronary angiography was available for 27 patients. Exercise tests for both tracers were carried out on an ergometric bicycle during the same day and the levels of exercise achieved for the thallium studies were very similar to those achieved for teboroxime. Imaging was performed in three planar projections and sudies were evaluated using a model with 4 territories: septal and anterior assumed to correspond to the LAD artery, lateral and latero-posterior (= LCX), inferior and posterior (= RCA) and apex. Classification of results was: normal, ischemic, infarcted and infarcted with ischemia. With reference to the thallium-201 results, agreement was found in 86% (37/43) of normal regions and in 82% (63/77) of abnormal regions. Relative to documented coronary artery lesions (27 patients) sensitivity and specificity of thallium and teboroxime for exact correspondence between arteries and territories were, respectively: thallium, se = 71%, sp = 64%, teboroxime, se = 67%, sp = 75%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clinical experience with technetium-99m teboroxime scintigraphy in patients referred for myocardial perfusion evaluation. 146 25

Recent studies indicate that preconditioning of the heart by repeated stunning protects it from subsequent ischemic injury. Such myocardial preservation is likely to be due to adaptive modification of lipid composition and dynamic structure of cellular membrane. To test this hypothesis, swine heart was subjected to four episodes of 5 min stunning by LAD occlusion, followed by 10 min of reperfusion after each stunning. The heart was then made regionally ischemic for 60 min by LAD occlusion, followed by 6 h reperfusion. A control heart was perfused for 60 min, followed by 60 min ischemia and 6 h reperfusion. Free fatty acids (FFA) accumulated in the control heart during ischemia, as expected, which was further enhanced by reperfusion. The FFA level was also enhanced during ischemia in stunned myocardium. However, this FFA level was almost restored during reperfusion. The levels of unsaturated fatty acids (UFA) such as oleate, linoleate, and arachidonate followed a similar pattern. Membrane fluidity, monitored by fluorescence polarization, was decreased during ischemia and reperfusion in the unstunned heart, with the corresponding increase in microviscosity. The increased microviscosity was significantly reduced by stunning. Since FFA are presumably generated from membrane phospholipids, these results suggest that stunning may cause the incorporation of a greater proportion of PUFA in membrane phospholipids, leading to preservation of membrane phospholipids and maintaining the membrane fluidity, which may be at least partially responsible for the attenuation of ischemic reperfusion injury.
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PMID:Preconditioning of heart by repeated stunning: adaptive modification of myocardial lipid membrane. 148 86

The potentially ischemia-protective effect of ECG-synchronized coronary venous retroperfusion (SRP) with arterial blood via the coronary sinus (CS) was assessed in 26 patients (56 +/- 10 years, 22 male, 4 female) in the clinical scenario of PTCA of a proximal LAD stenosis. In six additional patients the SRP procedure failed due to anatomical or technical reasons. In an intraindividual comparison at least two standardized balloon inflations for 60 seconds at 6-8 atm were performed in randomized order with and without continuous SRP at a flow rate of 200 +/- 46 ml/min. Under both conditions echocardiographic regional wall motion, ST depression in leads V1-6, hemodynamic parameters and symptoms expressed in a pain score were continuously monitored during angioplasty. This study revealed that the echocardiographic regional wall motion score in the perfusion territory of the dilated artery increased from 1.65 +/- 1.81 at baseline to 5.65 +/- 2.88 (p < 0.001) during a one minute dilatation without SRP. With SRP-support the regional wall motion at 1 minute angioplasty was significantly improved to 3.55 +/- 2.80 (p < 0.025). Moreover, the ischemic ECG-changes were markedly less pronounced, whereas the subjective perception of anginal pain was not different as a function of SRP-support. Thus, the simultaneous coronary venous retroperfusion with arterial blood has ischemia-protective potential in elective PTCA of a proximal LAD stenosis and may reduce ischemic dysfunction with prolonged balloon inflations.
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PMID:[Synchronized coronary venous retroperfusion: protection from ischemia in coronary angioplasty (PTCA)]. 149 32

To test the hypothesis that a small field of view portable multicrystal scintillation camera can perform stress/rest combined LV function by first-pass and perfusion studies using 99mTc-teboroxime, 26 patients with positive stress thallium studies within 2 wk and 8 healthy volunteers were studied. A 241Am point source marker over the sternum was used for motion correction. Dynamic dual-isotope (99mTc/241Am) acquisition was performed following injection of 15.6 +/- 2.3 mCi of 99mTc-teboroxime at peak treadmill exercise. Two minutes later (blood-pool clearance), while still standing on the flat treadmill, 3-4 40-sec planar images were acquired. One hour later patients were reinjected with 22.7 +/- 3.4 mCi of 99mTc-teboroxime while standing in front of the camera and the same dynamic/static acquisition protocol repeated. The planar images were interpolated from a 20 x 20 matrix to a 160 x 160 matrix, a sharpening filter and an interpolative background subtraction algorithm applied. The scans were divided into segments, each scored as normal, reversible and fixed. The agreement with thallium imaging for identifying an abnormal scan was 24/26 (92%) and for identifying abnormal vascular territories was 43/52, (83%). Fourteen patients had exercise LVEF less than 50% and all had either prior myocardial infarction, myocardial infarction plus ischemia or LAD ischemia. Diagnostic planar perfusion images and exercise LVEF can be acquired in less than 4 min using 99mTc-teboroxime and a portable multicrystal scintillation camera.
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PMID:Left ventricular perfusion and performance from a single radiopharmaceutical and one camera. 161 87


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