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

The coronary collateral circulation of goat is very spare, so myocardiac ischemia model of goat can simulate the patient previously with normal coronary circulation and suddenly developing complete occlusion of coronary arteries. In this study 80 Chengdu goats were used, and the branches of their left coronary artery were ligated. Ventricular tachycardia (VT) developed in 23 goats and ventricular fibrillation (VF) in 39 goats. VT and VF both occurred in the early phase of acute myocardial ischemia, and both had 6 min as the median time of onset. In 71 cases data on the weight of myocardiac ischemic area were collected, in which the weight percentage of ischemic area relating to the ventricles of 34 goats with VF was significantly higher than that of 37 goats without VF (35.4 +/- 2.4% vs 19.5 +/- 1.9%). After coronary ligation, 9 cases directly precipitated into VF which could not be defibrillated. In the remaining 62 cases, the weight percentage of ischemic area of 21 cases with VT was higher than that of 41 cases without VT (32.9 +/- 2.8% vs 20.9 +/- 2.1%). The relationships between the incidence of VT or VF and the weight percentage of ischemic area were fitted with logistic curve. The likelihood of occurrence of VT or VF is increased as the weight percentage of ischemia area goes up.
Hua Xi Yi Ke Da Xue Xue Bao 1992 Sep
PMID:[Relation between the occurrence of malignant arrhythmia during acute myocardial ischemia and the weight of ischemic myocardium in goats]. 129 21

Lipid peroxidation initiated by oxygen free radicals played an important role in the pathogenesis of coronary heart disease. The purpose of this study was to explore the effects of Tian-Ma (Gastrodia elata Bl.) injection on myocardial infarct size and lipid peroxidation by observing serum malondialdehyde (MDA) levels. Twenty-six New Zealand rabbits were divided into control group (n = 6), ischemic group (n = 10), and Tian-Ma treated group (n = 10). Left ventricular branch (LVB) of coronary artery was ligated at its middle third in ischemic and treated groups. LVB was not ligated in control group. Tian-Ma injection was given intravenously (1 mg/kg) every 8 hours after ligation in treated group for 48 hours. Precordial 12-lead ECG mapping was recorded before operation and at 3, 24 and 48 hours after occlusion. Hemodynamic changes (HR, LVP) were monitored before and 0.5, 3 and 48 hours after ligation. Serum MDA levels were determined by thiobarbituric acid spectrophotometry before operation, and 0.5, 3, 9, 24, and 48 hours after ligation. Dual staining technique was used 48 hours after ligation to determine the area at risk and infarct size. The results showed that Tian-Ma injection did not decrease sigma ST elevation (P greater than 0.05), but NQ was significantly lower during ischemia in treated group (P less than 0.01), Tian-Ma injection reduced the area at risk by 23.5% (P less than 0.05) and infarct size by 34.5% (P less than 0.01). Tian-Ma injection significantly decreased the levels of serum MDA 24 and 48 hours after occlusion (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Hua Xi Yi Ke Da Xue Xue Bao 1992 Mar
PMID:[Effects of tian-ma injection on myocardial ischemia and lipid peroxidation in rabbits]. 139 26

After making theoretical analysis, we detected the relationship among the maximal tension of ventricular contraction, left ventricular end-systolic pressure and stroke volume, and then derived a new and simple method of evaluating left ventricular contractility, the slope of the left ventricular end-systolic pressure-volume relation (Emax). Twelve mongrel male dogs were used to test this method. The results show that the value of Emax (0.60 +/- 0.16 kPa/ml) coming from this simple method is very close to that from complicated method; this method has good repetitiveness and is very sensitive to the variation of myocardial contraction. Using the method for evaluating left ventricular contraction after ischemia, we found the Emax more cogent than other hemodynamic parameters. Therefore, this method is an efficient method of evaluating left ventricular contraction.
Hua Xi Yi Ke Da Xue Xue Bao 1995 Jun
PMID:[A new and simple method of evaluating left ventricular contractility and its application]. 749 28

Recent research has shown that repeated brief myocardial ischemia (RBMI) can increase the tolerance of myocardium to a subsequent sustained ischemia and have protective effects on myocardial cells. With the isolated rat heart Langendorff model, we investigated the effects of RBMI on myocardial morphology, systolic function, coronary flow rates (CFR), myocardial membrane phospholipid (PL) content and its marker enzyme's activity (5'-AMPase). The results showed: After ischemia-reflow, the HR, LVP and CFR in control and experimental groups had no significant difference (P > 0.05). But the PL content and specific activity of 5'-AMPase were significantly higher in the experimental group than that in control group (P < 0.01, P < 0.05). And the observations of ultrastructure suggested that the myocardium of the experimental group was preserved better than that in control group. It was also shown that RBMI had protective effects on myocardial membrane structure, and however effective had no relation to CFR.
Hua Xi Yi Ke Da Xue Xue Bao 1995 Mar
PMID:[Experimental studies of protective effects of ischemic myocardium preconditioning and its mechanism]. 765 38

Calcium antagonists are generally considered to have no substantial effect on repolarization of the myocardium, so they have no direct effect on T wave, either. But in a pig model of myocardial ischemia, intracoronary nifedipine was found to reverse the inverted T wave induced by ischemia to upright promptly. Ten pigs were anesthetized with the chest opened, anterior interrentricular branch of left coronary artery (LAD) was narrowed to 4.67 kPa of LAD pressure, and then adenosine or nifedipine was infused into the coronary respectively. During the 9-minute ischemia, intracoronary adenosine or intracoronary nifedipine got the similar HR, LVEDP, LVDP, CAP, CAQ, and the intracoronary adenosine even got higher CAQ than the intracoronary nifedipine did. However, the T wave was retained inverted during the adenosine infused, but during the intracoronary nifedipine, the inverted T wave was promptly turned upright. The relevant factors and mechanisms are discussed.
Hua Xi Yi Ke Da Xue Xue Bao 1994 Sep
PMID:[Effect of nifedipine on T wave in ischemic myocardium]. 789 45

To have a better understanding of reperfusion-induced ventricular fibrillation (VF), we studied the relevant morbidity in pigs and compared it with that of the ischemia-induced VF. In 10 hearts of anesthetized chest-open pigs, a total of 127 cycles of various degrees and varied duration of ischemia and reperfusion were completed. VF occurred 13 times (10.2%). Of these, 11 were ischemia-induced VF, while only 2 were reperfusion-induced VF. In two cases of ischemia-induced VF, electric defibrillation failed before the reestablishment of left anterior interventricular branch of coronary artery flow, but after adequate reflowing, all VF turned out to be sinus-rhythm by electric defibrillation. The results suggest that ventricular fibrillation be mainly induced by ischemia but less induced by reperfusion.
Hua Xi Yi Ke Da Xue Xue Bao 1994 Sep
PMID:[Comparative study of ischemia-induced and reperfusion-induced ventricular fibrillation in pigs]. 789 47

A pyranocoumarin compound, 3'-angeloyloxy-4'-acetoxy-3',4'-dihydroseselin (Pd-Ia), isolated from Bai-Hua Qian-Hu, a Chinese medicine, is known to possess a Ca2+ channel antagonist action. We examined the effect of Pd-Ia on cardiohemodynamics and regional myocardial dysfunction after transient ischemia in anesthetized open-chest dogs. I.v. injections of Pd-Ia (0.1-3.0 mg/kg, n = 7) significantly and dose dependently increased coronary blood flow and decreased mean aortic pressure, maximal rate of rise in left ventricular pressure, rate pressure product and systemic vascular resistance, together with a slight increase in heart rate. Diltiazem (0.03-1.00 mg/kg, n = 6) showed effects on the cardiohemodynamics similar to those of Pd-Ia, except for a marked decrease in heart rate. The effects of Pd-Ia on mean aortic pressure and rate pressure product were approximately 10 times less potent than those of diltiazem. In the second experiment, the effect of a 30-min infusion of Pd-Ia (0.15 mg/kg/min) or vehicle on regional myocardial dysfunction was examined in 16 anesthetized dogs subjected to a 15-min occlusion of the left anterior descending coronary artery followed by a 3-h reperfusion. Infusion of Pd-Ia was started 15 min before coronary occlusion. The vehicle caused a decrease in percent segment shortening throughout the reperfusion period (n = 8). However, Pd-Ia at the dose that produced no significant changes in cardiohemodynamics resulted in a marked improvement in percent segment shortening of the ischemic and reperfused myocardium (n = 8, P < 0.05 vs. control group).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of a pyranocoumarin compound isolated from a Chinese medicinal plant on ischemic myocardial dysfunction in anesthetized dogs. 792 2

To investigate the mechanism of myocardial; tunning, a Langendorff model of rat hearts (n = 18) underwent 15 min ischemia with coronary flow at 0.2 ml/min and 10 min reperfusion with Ringer's solution of 1.06 mmol/L Mg2+. Histological exam revealed no myocardial necrosis. However, the recovery of pressure product (RPP) was only 77% compared with control period. The myocardial Ca2+ content and water content were significantly increased (P < 0.01, vs control hearts). Pretreatment with high concentration of Mg2+ (2.4 mmol/L) improved the recovery of postischemic ventricular function, attenuated the Ca2+ overload and myocardial edema. The results indicated that a brief period of low-flow ischemia could produce a postischemic ventricular dysfunction-the myocardial stunning. Calcium overload and myocardial edema might be two pathogenic factors. An increased Mg2+ had a protective effects on postischemic ventricular dysfunction, which may involve the following mechanisms: reduced Ca2+ overload and attenuated myocardial edema.
Hua Xi Yi Ke Da Xue Xue Bao 1993 Sep
PMID:[Pathogenic factors of postischemic ventricular dysfunction and effects of magnesium]. 828 88

Thirty newborn pigs within 3 days of life were randomly divided into different groups according to the time of hypoxic-ischemic encephalopathy. The results showed that the brain damage and pathologic changes were most obvious in the 60 min hypoxia-ischemic group. Brain edema was observed in every group, especially in the group where hypoxia-ischemic lasted for more than 30 min. Cerebromalacia and hemorrhage in ventricles of brain and in arachnoid were observed, and these were particularly noticed in the group where hypoxia-ischemia lasted for 60 min.
Hua Xi Yi Ke Da Xue Xue Bao 1995 Sep
PMID:[Observation on the animal model of hypoxic-ischemic encephalopathy and the change of pathology in newborn pigs]. 858 4

To study the kidney lesions complicated by hypoxic ischemic encephalopathy (HIE) in newborn, we successfully established a neonatal pig model of HIE. Changes in brain tissue similar to those of newborn in HIE were detected after 2 hours of hypoxia and ischemia. Meanwhile, swelling of kidneys, hemorrhage below encapsules, swellin of tubular epithelial cells, necrosing and falling of a few tubular epithelial cells, and narrowing of tubular lumens were observed. The basement membranes of renal tubules remained normal serum BUN and creatinine increased significantly after experiment compared with before (P < 0.025 and P < 0.05 respectively). The results showed that the kidney of neonatal pig was damaged in HIE. But the injury was not severe. After 72 hours free from hypoxia, the structure and function recovered approximately from the injury.
Hua Xi Yi Ke Da Xue Xue Bao 1997 Jun
PMID:[Kidney lesions complicated by hypoxic ischemic encephalopathy of neonatal pig]. 1068 35


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