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Objective: To explore research the protective effect of ischemia preconditioning to rabbits′myocardium injury of ischemia reperfusion, and discuss its mechanism. Methods: We randomly divide rabbits into 3 groups ( 8 rabbits every group ) , namely non-operation group . ischemia reperfusion group ( IR ) . ischemia preadaptation group ( IP ), and observed the level of enzymatic dynamics of myocardium,SOD,MDA, ET and correlation peptide of calcitonin gene. Results: In terms of the level of enzymatic dynamics of myocardium, SOD,MDA, ET and CGRP, the differences between IR and IP are very obviously (P
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Objective: To establish porcine chronic ischemic myocardium model and to evaluate ultrasonic integrated backscatter(IBS) and Doppler tissue imaging(DTI) in detecting this model. Methods: An Ameroid constrictor was placed around the porcine proximal left circumflex artery. The calibrated average image intensity (%AⅡ), cyclic variation of IBS (CVIB), the subendo-epicardical gradient index (TGI) and the spectrum of left ventricular papillary muscle level short axis view (LVPM-SAM) and apical four chamber view (AP-4CV) were measured at normal state, 2 w, 4 w, 6 w and 8 w after Ameroid placement. Results: Normal %AⅡ, CVIB and TGI were 2.29?0.32,(9.69?2.22)dB and 0.22? 0.08 respectively. After Ameroid placement, the %AII increased gradually, the CVIB decreased gradually, and the decrease was higher in subepicardium than that in subendocardium. The most obvious decrease of TGI occurred from 2 w to 4 w after Ameroid placement and became zero at 8 w(P
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PURPOSE: To compare the accuracy with which electron beam tomography (EBT) and 99m Tc-MIBI scanning measure myocardial perfusion valve. MATERIALS AND METHODS: Twenty-two subjects [normal volunteers (n = 6), patients in whom ischemic heart disease was diagnosed (n = 5), and those in whom ischemic heart disease was suspected but who were found to be normal (n = 11)] were involved in this study. EBT was performed after bolus injection of contrast media (50 ml of Iopamiro 370 or Optiray 350, 3 ml/sec). The myocardium was divided into 16 segments according to the classification devised by the American Society of Echocardiography, and each myocardial perfusion value was calculated by post-image processing. A pharmacologic stress test was performed in all subjects except four patients with acute myocardial infarction, and myocardial perfusion reserve ratios were assessed. Single photon emission computed tomography (SPECT) was performed after the injection of 20 mCi of 99m Tc-MIBI. Any segments with moderate to severe photon defect on visual analysis of SPECT were identified and perfusion values determined by EBT in normal and ischemic segments were compared. RESULTS: No difference in myocardial perfusion was found between volunteers and the suspected group. Their perfusion values were 0.71 +/-0.14 ml/g/min in the resting state and 1.16 +/-0.24 ml/g/min on the stress test and the myocardial perfusion reserve ratio was, therefore, 1:1.68 +/-0.38. In ischemic patients, 99m Tc-MIBI scanning revealed a perfusion defect in 28 segments, and on EBT the measurement obtained was 0.54 +/-0.19 ml/g/min. The remaining 324 perfusion segments shown by SPECT to be normal showed a perfusion value of 0.79 +/-0.22 ml/g/min on EBT. CONCLUSION: Compared with 99mTc-MIBI scanning, the measurement of myocardial perfusion by EBT provides absolute quantification of perfusion value and more detailed anatomic information.
Subject(s)
Humans , Classification , Contrast Media , Echocardiography , Exercise Test , Iopamidol , Myocardial Infarction , Myocardial Ischemia , Myocardium , Perfusion , Tomography, Emission-Computed, Single-Photon , Tomography, X-Ray Computed , VolunteersABSTRACT
PURPOSE: In order to determine the value of first-pass MR imaging in the diagnosis of myocardial ischemia, first-pass perfusion abnormality of coronary artery stenosis was observed in MRI after gadopentate dimeglumine (Gd-DTPA) enhancement. MATERIALS AND METHODS: The left anterior descending (LAD) coronary arteries of six dogs were subjected to approximately 70% stenosis confirmed by coronary angiography. Half an hour after adenosine and 99mTc-sestamibi infusion, Gd-DTPA (0.2 mmol/kg) and methylene blue were administered and termination was induced with potassium chloride. SE T1-weighted and single-photon emission computed tomography (SPECT) images were subsequently obtained and the findings of perfusion defect compared with specimen stain. Three dimensionally reconstructed MR images were used to measure signal intensity (SI) of normal myocardium and perfusion defect from their sectional and total volume. RESULTS: Five of six dogs with LAD artey stenosis ranging from 66% to 73% displayed perfusion defect on MRI, SPECT, and specimen stain, but the remaining dog with stenosis of 58% showed no such defect. MRI showed the perfusion defect as distinct low SI, enabling the measurement of percentage perfusion defect (24.4+/-5.4%), which increased inferiorly. SI of normal myocardium and perfusion defect decreased inferiorly; their difference indicated stenosis-induced perfusion loss according to section location. Volumetric SI of normal myocardium and perfusion defect were 3.42+/-0.52 and 2.16+/-0.45, respectively (p < 0.05). CONCLUSION: Gd-DTPA enhanced MRI displayed first-pass perfusion abnormality of coronary artery stenosis as perfusion defect with distinct low SI ; this enabled the measurement of its volume and SI changes according to section location, and thus indicated the value of first-pass MR imaging in the diagnosis of myocardial ischemia.
Subject(s)
Animals , Dogs , Adenosine , Constriction, Pathologic , Coronary Angiography , Coronary Stenosis , Coronary Vessels , Diagnosis , Gadolinium DTPA , Magnetic Resonance Imaging , Methylene Blue , Myocardial Ischemia , Myocardium , Perfusion , Potassium Chloride , Technetium Tc 99m Sestamibi , Tomography, Emission-Computed , Tomography, Emission-Computed, Single-PhotonABSTRACT
Objective To observe the effect of Huangqi Danshen Drop Pill(HDDP) on pituitary (Pit) induced acute myocardium ischemia. Methods Acute myocardium ischemia rat model was established by sublingual venous injection of Pit(0. 35U/kg). The changes of the T wave ( II channel ECG) and serum contents of lactate dehydrogenase (LDH), CK, superoxide dismutase (SOD) and malondialdehyde (MDA) were observed in various times after Pit injection. Results HDDP could significantly lower the height of T waves, increase SOD activity and decrease MDA content. Conclusion HDDP can improve acute myocardium ischemia induced by Pit.
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Experimental studies on the myocardial ischemia and reperfusion injury in 16 anaethetized SDrats,of which,8 animals were pretreated with morphine(5 mg/kg,i.p.)for preventing of arrhyth-mias,were studied immunocytochemically with anti-muscle actin specific monoclonal antibody (HHF_(35)),8 shan-operated rats were used as control.With HHF_(35) ABC immunocytochemical method,the area of myocardial ischemia and reperfusion injury(without morphine)showed decrease or ab-sence of staining,large areas of staining loss were also seen.In the group with morphine,only smallfoci of staining absence were shown.The myocardium in control animals showed evenly positive stain-ing.No change were seen with HE staining in all groups.The results obtained with HHF_(35) stainingsupport its important value in studying on myocardic reperfusion injury,and indicated that the degreeof myocardic damage may be relative to the arrhythmias in myocardial reperfusion injury.
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Methoxyadiantifoline ( MAF) is a new alkloid isolated from Thalictrum Omeience W.T.Wang.During 3 min reperfusion after 10 min of coronary ligation, MAF 5 ?mol/L significantly decreased the incidence of isolated rat hearts with ventricular arrhythmias ( VF and VT ) . It delayed the onset of ventricular fibrillation and shortened its duration and markedly prolonged the time of normal sinus rhythm. It also significantly decreased the release of LDH from the myocardium in isolated rat hearts. In addition , MAF 5 ?mol/L could decrease the heart rate and coronary resistance. The results suggest that MAF possessed protective effects on the reperfusion injury in isolated rat hearts.
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Objective: To investigate the angiogenic potentiality of angiogenin in ischemic myocardium and estimate the possibility of its application in biologic treatment. Methods: Recombinant human angiogenin derivative Asp116His was applied in an acute myocardial infarction model in rabbits which were established by direct intramyocardial injection into the border zone of the ischemic myocardium. The animals were sacrificed on the eighth postoperative day and their hearts were harvested and subjected to histologic studies. Results: Myocardium around the injection sites was apparently less ischemia in the experiment group as compared with control groups. A large number of small vessels were observed in the interstitial tissues and even more were revealed in the myocardium on immunohistochemistry studies. Conclusion: The results indicate for the first time that angiogenin or its derivatives may act on ischemic myocardium and stimulate neo angiogenesis, which holds great promise for their future application in biologic revascularization of ischemic myocardium.