Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To assess the protective effects of L-carnitine (LC) infusion on ischemic heart disease, 30 patients who had angina and ischemic ECG changes during exercise were evaluated by bicycle ergometry. They were categorized in LC and non-treatment (NT) groups. There were no significant differences in age and sex between the 2 groups. Before exercise, 15 patients (9 males and 6 females) received 60 mg/kg LC and the results including hemodynamics, coronary circulation, and cardiac metabolism at rest and during exercise were compared with those of the NT group studied in the same protocol (50 watts x to cycle, 15 min). At the end of 30 min LC drip infusion, the arterial carnitine content (LC (a)) reached 1,980 +/- 257.3 microM and then was maintained at 1,212.7 +/- 136.2 microM during exercise. There was no correlation of LC (a) with the coronary arterio-venous difference nor with myocardial uptake of LC. Although there was no significant difference in coronary blood flow (CBF: mliters/100 g/min) between the LC and NT groups at rest (LC: 92.1 +/- 29.0 vs NT: 88.0 +/- 26.5), CBF during exercise increased significantly in the LC group compared with the NT group (LC: 230.4 +/- 113.8 vs NT: 139.1 +/- 52.7; p < 0.05). In the NT group, there was no significant change in coronary arterio-venous oxygen difference ((a-cs) O2: vol %) during exercise, but in the LC group (a-cs) O2 increased significantly from 10.2 +/- 1.3 to 11.5 +/- 1.9 (p < 0.01). Furthermore, although there was no significant difference in myocardial oxygen consumption (MVO2: mliters/100 g/min) at rest between the 2 groups (LC: 9.30 +/- 2.96 vs NT: 9.71 +/- 3.09), it increased significantly in the LC group compared with the NT group during exercise (LC: 25.11 +/- 9.98 vs NT: 15.55 +/- 6.09). MVO2/LVWI (LVWI = left ventricular work index) and MVO2MT (MT = myocardial tension) did not significantly differ at rest between the 2 groups. However, these 2 indices decreased significantly during exercise (p < 0.05) in the NT group, and remained unchanged in the LC group, showing a significant difference between the 2 groups (both p < 0.05). In myocardial energy substrates, the myocardial uptake ((a-cs) x CBF) of free fatty acid (FFA: muEq/100 g/min) increased significantly in the LC group compared with that of the NT group (LC: 10.16 +/- 13.26-->31.88 +/- 27.58* vs NT: 16.02 +/- 27.92-->18.11 +/- 31.00;* = p < 0.05, LC vs NT).
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PMID:[Effect of L-carnitine in patients with ischemic heart disease]. 184 35

In clinical and experimental studies we assessed images of digital subtraction coronary angiography (DSA) for evaluating regional myocardial perfusion. Myocardial perfusion was assessed by injecting contrast medium into the coronary artery, and by imaging the regional myocardium using DSA. On the time-density curve obtained from the myocardial region of interest, we calculated the time to peak concentration (TPC) and the exponential washout rate (T). TPC and T were measured in five patients with stable effort angina pectoris (AP) and left anterior descending (LAD) lesions before and after percutaneous transluminal coronary angioplasty (PTCA). The values of 1/T increased significantly from 0.09 +/- 0.02 l/sec to 0.21 +/- 0.04 l/sec (p less than 0.01) after PTCA, but l/TPC did not change. No significant difference in ejection fractions was observed between the patients with AP and the normal subjects (n = 7), while the regional percent area shrinkage in the anterolateral and apical regions supplied by the LAD was significantly decreased in the patients with AP compared with those of normal subjects (anterolateral: 39.8 +/- 8.8% vs 51.3 +/- 6.8%, apical: 36.6 +/- 8.4% vs 52.4 +/- 13.4%, both p less than 0.01). In 10 anesthetized dogs with varying degrees of reduction in the left circumflex coronary artery (LCX) blood flow (CBF: categories of stenosis (S1-S5), we compared 1/TPC and 1/T with regional myocardial function (systolic wall thickening: %WTh). With varying LCX stenosis, there were no significant changes in heart rate and mean aortic pressure and significant linear correlations were observed between %WTh and 1/TPC (r = 0.51), between %WTh and 1/T (r = 0.55). At S1 (CBF: 100-90% of the control), neither %WTh nor 1/TPC differed from that of the controls, but 1/T was significantly decreased (80% of the controls, p less than 0.01). From S3 (CBF: 79-60%) to S5 (CBF: 39-0%), %WTh, 1/TPC and 1/T were significantly decreased from those of the control levels (all p less than 0.01). However, at S5 (CBF: 39-0%) the values of 1/TPC (71% of controls) and 1/T (33%) did not differ from those at S4; whereas, %WTh was markedly reduced and the systolic thinning of the ventricular wall occurred at S5. Therefore, in critical coronary stenosis, 1/T was more sensitive than 1/TPC or wall dynamics for assessing myocardial ischemia. Both 1/TPC and 1/T, as well as %WTh, were useful for assessing moderate myocardial ischemia; however, these DSA indices had considerable limitations for evaluating the severity of myocardial ischemia when CBF was markedly reduced.
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PMID:[Comparison of myocardial perfusion assessments by digital subtraction angiography with those of left ventricular wall dynamics]. 213 31

Open chest anesthetized dogs were given dopamine (DA) in intravenous (i.v., 2-16 micrograms.kg-1.min-1) and intracoronary (i.c., 10-40 micrograms.min-1) infusions. The drug effect was analyzed using the nonselective beta-adrenoceptor antagonist oxprenolol (0.5 mg.kg, i.v.) and the nonselective alpha-adrenoceptor antagonist phentolamine (1.0 mg.kg-1, i.v.). Coronary blood flow (CBF, electromagnetic flowmeter), arterial pressure and left ventricular contractile force (strain gauge) were measured. Coronary vascular responses were characterized by changes of CBF and calculated coronary vascular resistance (CVR). In the control state, DA-induced arterial hypertension (i.v. administration) and augmented inotropism (i.v. and i.c. administration) were accompanied by a dose-dependent coronary vasodilatation (increase of CBF and decrease of CVR). Oxprenolol converted coronary vasodilatation to vasoconstriction during DA infusions and blocked the inotropic action; the hypertensive DA effect remained unaffected. Similar alterations were observed after a transitory (45 min) regional myocardial ischemia, elicited by coronary occlusion. On the other hand, phentolamine-pretreatment potentiated the DA-induced coronary vasodilatation and converted hypertension to hypotension; the inotropic component of the DA action was not affected. After combined beta- and alpha-blockade, DA failed to increase CBF and decrease CVR during the infusion periods. Instead, the drug elicited a very slight coronary vasoconstriction. I.c. (but not i.v.) infusions of DA were regularly followed by a rebound-like, transient CBF increase, even after combined beta- and alpha-blockade. These results show that all of the multifactorial determinants of the direct, steady state coronary effects of DA can be ascribed to alpha- and beta-adrenoceptor stimulation, whereas the hypothetical dopaminergic coronary vascular receptors do not seem to play a decisive role in these responses. However, undefined after-effects provoked by i.c. DA, may be connected with specific dopaminergic effects.
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PMID:Dopamine-induced coronary effects in the dog heart attributed to beta- and alpha-adrenergic mechanisms. 284 27

Cross-sectional imaging techniques have the potential for measuring left ventricular (LV) wall thickness (WTh) dynamics. This proposition was assessed in a canine experimental model, using prospectively gated computed tomography (CT) scans before and after occlusion of a coronary artery. Gated CT scans detected loss of wall thickening in the LV anterior segment immediately after occlusion of the left anterior descending coronary artery in two dogs. After demonstrating the feasibility of using gated CT scans to demonstrate ischemic functional abnormalities by monitoring wall thickness changes, we assessed the relationship between regional wall thickening dynamics and coronary blood flow in eight anesthetized dogs. Graded circumflex (Cx) coronary artery stenosis (CAS) was produced while sonomicrometer crystals continuously recorded LV WTh and extent of wall thickening (EWTh) in the anterior descending and the Cx distributions. The first significant change in EWTh in the ischemic segment occurred at 33% decrease in CBF (P less than .05) which corresponded to an 80% CAS. At 33% decrease in CBF, there was a concomitant increase in EWTh in the normal segment. In conclusion, we have demonstrated the feasibility of using gated CT to detect myocardial ischemia by monitoring WTh dynamics. Physiologic studies document a close relationship between regional wall thickening dynamics and coronary blood flow and should provide a basis for interpretation of dynamic cross-sectional images of the left ventricle in ischemic heart disease.
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PMID:1982 Memorial Award Paper. Detection of regional myocardial dysfunction during ischemia with computerized tomography: documentation and physiologic basis. 712 14

The effects of periodic obstructive apneas on systemic and myocardial hemodynamics were studied in nine preinstrumented sedated pigs under four conditions: breathing room air (RA), breathing 100% O2, breathing RA after critical coronary stenosis (CS) of the left anterior descending coronary artery, and breathing RA after autonomic blockade with hexamethonium (Hex). Apneas with RA increased mean arterial pressure (MAP; from baseline 103.0 +/- 3.5 to late apnea 123.6 +/- 7.0 Torr, P < 0.001) and coronary blood flow (CBF; late apnea 193.9 +/- 22.9% of baseline, P < 0.001) but decreased cardiac output (CO; from baseline 2.97 +/- 0.15 to late apnea 2.39 +/- 0.19 l/min, P < 0.001). Apneas with O2 increased MAP (from baseline 105.1 +/- 4.6 to late apnea 110.7 +/- 4.8 Torr, P < 0. 001). Apneas with CS produced similar increases in MAP as apneas with RA but greater decreases in CO (from baseline 3.03 +/- 0.19 to late apnea 2.1 +/- 0.15 l/min, P < 0.001). In LAD-perfused myocardium, there was decreased segmental shortening (baseline 11.0 +/- 1.5 to late apnea 7.6 +/- 2.0%, P < 0.01) and regional intramyocardial pH (baseline 7.05 +/- 0.03 to late apnea 6.72 +/- 0. 11, P < 0.001) during apneas with CS but under no other conditions. Apneas with Hex increased to the same extent as apneas with RA. Myocardial O2 demand remained unchanged during apnea relative to baseline. We conclude that obstructive apnea-induced changes in left ventricular afterload and CO are secondary to autonomic-mediated responses to hypoxemia. Increased CBF during apneas is related to regional metabolic effects of hypoxia and not to autonomic factors. In the presence of limited coronary flow reserve, decreased O2 supply during apneas can lead to myocardial ischemia, which in turn adversely affects left ventricular function.
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PMID:Systemic and myocardial hemodynamics during periodic obstructive apneas in sedated pigs. 951 95

Patients with ischemic heart disease are often complicated with cerebrovascular disease. The purpose of this study is to examine the usefulness of Xe-CT CBF study in patients with cerebral arterial occlusive disease before cardiac surgery with cardiopulmonary bypass. This study was carried out in 11 patients suffered from ischemic heart disease with cerebrovascular diseases. They had severe stenoses or occlusions of cerebral arteries. Cerebral hemodynamics was measured by Xe-CT. There were no ischemic complications in the brain or heart during the study. Hemispheric CBF in the occlusive side is lower than that in the non-occlusive side. Cerebral ischemic events occurred in one patient after the cardiac surgery. Xe-CT CBF study can be performed safely in patients with ischemic heart disease. The patients with low CBF and low cerebrovascular reserve, had a greater risk of cerebral complication after cardiac surgery with cardiopulmonary bypass.
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PMID:Usefulness of hemodynamic evaluation in patients with major cerebral arterial occlusive disease before cardiac surgery. 1075 Mar 47

Cytochrome P450 epoxygenase metabolites of arachidonic acid, EETs, have multiple cardiovascular effects, including reduction of blood pressure, protection against myocardial ischemia-reperfusion injury, and attenuation of endothelial apoptosis. This study investigated the hypothesis that transgenic mice with endothelial overexpression of CYP2J2 (Tie2-CYP2J2-Tr) would be protected against global cerebral ischemia induced by bilateral common carotid artery occlusion (BCCAO) and action mechanisms of EETs on cerebral ischemia in cultures of astrocytes exposed to oxygen-glucose deprivation (OGD). Tie2-CYP2J2-Tr mice had significantly increased CYP2J2 expression, increased 14,15-EET production, increases regional cerebral blood flow (rCBF) and microvascular density, decreased ROS production, decreased brain infarct size and apoptosis after ischemia compared to wild type mice, these were associated with increased activation of the PI3K/AKT and apoptosis-related protein in ischemic brain. Addition of exogenous EETs or CYP2J2 transfection attenuated OGD-induced apoptosis in astrocytes via activation of PI3K/AKT and anti-apoptosis pathways. However, these effects were reduced by pretreatments with inhibitor of the PI3K (LY294002) and 14,15-EET (14,15-EEZE), respectively. These results indicate that CYP2J2 overexpression exerts marked neuroprotective effects against ischemic injury by a mechanism linked to increased level of circulating EETs and increases CBF and reduction of apoptosis.
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PMID:Cytochrome P450 2J2 is protective against global cerebral ischemia in transgenic mice. 2304 Dec 91