Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151814 (coronary occlusion)
 3,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The changes in spatio-temporal patterns of magnetocardiograms were investigated following injection of superparamagnetic iron-oxide (SPIO) nanoparticles using a dog model of ischemia/reperfusion. Acute myocardial infarction was induced by ligation of the left anterior descending coronary in two anesthetized open-chest dogs. Following 60 min coronary occlusion and 30 min reperfusion, dogs were subjected to injections of SPIO at a dose of 0.56 mg Fe/kg using a catheter inserted into the left atrium. Magnetocardiograms were measured before coronary occlusion, 15 min after reperfusion and immediately after administration of the SPIO. Magnetic field maps of early reperfused myocardium showed spatio-temporal field distributions consistent with anterior myocardial infarction. Magnetic field distribution measured after injection of SPIO revealed additional spatio-temporal features most prominent during ventricular repolarization due to augmentation/fragmentation of the ST-segment detected at several sensor locations. No significant differences in MCG patterns were noted following contrast agent injections in a dog without coronary occlusion. In conclusion, preliminary experimental evidence appears to support the notion that superparamagnetic contrast agents increase the sensitivity of standard MCG and may have an important implication for magnetocardiography in the assessment of regional myocardial ischemia, infarction and perfusion.
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PMID:Changes in magnetocardiogram patterns of infarcted-reperfused myocardium after injection of superparamagnetic contrast media. 1601 81

The aim of the present study was to investigate if hyperlipidemia interferes with the infarct size-limiting effect of postconditioning and to study the involvement of peroxynitrite in this phenomenon. Rats were fed a 2% cholesterol-enriched or normal diet for 12 wk. Infarct size by triphenyltetrazolium chloride staining was measured in hearts isolated from both groups and subjected to 30 min coronary occlusion followed by 120 min reperfusion with or without the postconditioning protocol induced by six cycles of 10 s coronary occlusion and 10 s reperfusion at the onset of the reperfusion. Postconditioning significantly decreased infarct size in the normolipidemic but not in the hyperlipidemic group. Postconditioning increased cardiac 3-nitrotyrosine concentration (a marker for peroxynitrite formation) in the normal but not in the cholesterol-fed group when measured at the 5th min of reperfusion. Next, we tested if the postconditioning-induced acute increase in peroxynitrite is involved in the cardioprotection in normolipidemic animals in separate experiments. Postconditioning failed to decrease infarct size in the presence of the peroxynitrite decomposition catalyst 5,10,15,20-tetrakis-[4-sulfonatophenyl]-porphyrinato-iron [III] (20 mg/l) in normolipidemic animals. We conclude that an early increase in peroxynitrite after postconditioning plays a role in cardioprotection. Furthermore, hyperlipidemia blocks the cardioprotective effect of postconditioning at least in part via deterioration of the postconditioning-induced early increase in peroxynitrite formation.
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PMID:Cholesterol diet-induced hyperlipidemia impairs the cardioprotective effect of postconditioning: role of peroxynitrite. 1973 63

Therapeutic intracavitary stem cell infusion currently suffers from poor myocardial homing. We examined whether cardiac cell retention could be enhanced by magnetic targeting of endothelial progenitor cells (EPCs) loaded with iron oxide nanoparticles. EPCs were magnetically labeled with citrate-coated iron oxide nanoparticles. Cell proliferation, migration, and CXCR4 chemokine receptor expression were assessed in different labeling conditions and no adverse effects of the magnetic label were observed. The magnetophoretic mobility of labeled EPCs was determined in vitro, with the same magnet as that subsequently used in vivo. Coronary artery occlusion was induced for 30 min in 36 rats (31 survivors), followed by 20 min of reperfusion. The rats were randomized to receive, during brief aortic cross-clamping, direct intraventricular injection of culture medium (n = 7) or magnetically labeled EPCs (n = 24), with (n = 14) or without (n = 10) subcutaneous insertion of a magnet over the chest cavity (n = 14). The hearts were explanted 24 h later and engrafted cells were visualized by magnetic resonance imaging (MRI) of the heart at 1.5 T. Their abundance in the myocardium was also analyzed semiquantitatively by immunofluorescence, and quantitatively by real-time polymerase chain reaction (RT-PCR).Although differences in cell retention between groups failed to be statistically significant using RT-PCR quantification, due to the variability of the animal model, immunostaining showed that the average number of engrafted EPCs was significantly ten times higher with than without magnetic targeting. There was thus a consistent trend favoring the magnet-treated hearts, thereby suggesting magnetic targeting as a potentially new mean of enhancing myocardial homing of intravascularly delivered stem cells. Magnetic targeting has the potential to enhance myocardial retention of intravascularly delivered endothelial progenitor cells.
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PMID:Can magnetic targeting of magnetically labeled circulating cells optimize intramyocardial cell retention? 2208 Jul 48

LV is a pressure-generating pump which endures pressure overload, while RV is a flow-generating pump intolerant of pressure overload. Therefore, RV pump function (but not RV myocardial contractility) can easily fail in face of severe pulmonary arterial hypertension (PH) because of increased afterload. Available indexes of RV function are load dependent and incapable of accurately reflecting RV myocardial contractility. Animal RV in which myocardium is damaged extensively by either soldering iron or coronary occlusion can work well without causing systemic congestion or decreased SV. In clinical settings, evaluation of pre-treatment RV function in patients with PH has limited value in predicting prognosis. Furthermore, in virtually all patients with PH after successful lung transplantation, RV function has been reported to improve indicating that deteriorated RV function in patients with PH is due to an increase in RV afterload, but not to decreased RV myocardial contractility. In view of these facts, evaluation of RV function seems hardly useful in patients with PH.
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PMID:Nimura lecture: why are you evaluating RV function in patients with pulmonary arterial hypertension? 3029 8


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