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)

Diabetes mellitus (DM)-linked metabolic alterations and hypertension concomitantly accelerate or precipitate cerebrovascular and coronary heart disease, nephropathy, retinopathy and widespread macroangiopathy, thereby conferring to diabetic patients a very high risk of morbidity, disability and early death. Therefore, the long-term care for diabetic patients should be aimed at concomitant metabolic and blood pressure (BP) control. Dietary measures are indispensable; a high fibre, low fat, low salt diet is recommended, complemented with caloric restriction and physical exercise when body weight is above the ideal. Antidiabetic pharmacotherapy involves an unresolved dilemma. The desired achievement of euglycemia necessitates effective levels of insulin, but hyperinsulinemia (due to parenteral [over]treatment in insulin-dependent DM) is suspected to promote atherogenesis and represents a coronary risk factor and perhaps even facilitates hypertension. Considering antihypertensive pharmacotherapy, thiazide-type or loop diuretics are problematic drugs in DM because they can aggravate metabolic alterations. These agents also seem to exert only a limited preventive or regressive effect on left ventricular hypertrophy (LVH); beta-blockers are also not considered ideal, since they decrease the awareness of hypoglycemia and tend to promote glucose intolerance. Unselective beta-blockers in particular promote peripheral ischemia and insulin-induced hypoglycemia, while beta-blockers without intrinsic sympathomimetic activity lower serum HDL-cholesterol. Calcium antagonists and ACE inhibitors have equivalent antihypertensive efficacy, do not impair carbohydrate and lipid homeostasis or peripheral perfusion and can effectively improve LVH. Certain ACE inhibitors may even slightly ameliorate abnormal insulin sensitivity and plasma glucose levels. While alpha-blockers share most of these desirable properties, these agents are more prone to precipitate orthostatic hypotension in the diabetic patient. The non-thiazide diuretic indapamide and the serotonin2-antagonist ketanserin also combine antihypertensive efficacy with metabolic neutrality. The ultimate goal of therapy is to improve life prognosis. In essential hypertension, conventional drug treatment based on diuretics in high dosage satisfactorily reduced cerebrovascular but not coronary complications or sudden death. In diabetic patients, the influence of antihypertensive therapy on prognosis has not been assessed prospectively. Based on retrospective analyses, Warram et al reported a 3.8 times higher mortality in diabetics treated with diuretics alone, than in diabetics with untreated hypertension (Arch Intern Med. 1991;151:1350). H. H. Parving calculated that effective BP control in patients with diabetic nephropathy might reduce 10 year-mortality from about 65 to 20 percent (J Hypertension. 1990; 8[Suppl 7]:187).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Antihypertensive therapy in diabetic patients. 128 10

Arterial hypertension is the most frequent cause of a disturbance of coronary microcirculation. Inspite of having normal epicardial coronary arteries, patients with arterial hypertension often have symptoms of angina pectoris and a positive exercise tolerance test. The angina pectoris symptoms in patients with arterial hypertension are due to functional and structural alterations of the coronary microcirculation. Consequently, an antihypertensive therapy should not only aim at lowering blood pressure and reversing myocardial hypertrophy, but also to improve coronary microcirculation in order to avoid the consequences of chronic ischemia on the myocardium. Until now, only experimental studies have indicated that antihypertensive therapy can improve coronary flow reserve. To determine (also under clinical conditions) if coronary flow reserve can be improved, in 30 hypertensive patients maximal coronary blood flow, minimal coronary resistance, and coronary reserve (dipyridamol) were studied before and after a long-term antihypertensive treatment (9-12 months) with an ACE-inhibitor (enalapril 10-20 mg/d), a calcium channel blocker (diltiazem 120-180 mg/d) and a beta 1-selective beta-receptor-blocker (bisoprolol 5-10 mg/d). To assess the chronic effects rather than the acute effects of the antihypertensive pharmacon, coronary microcirculation was studied after intermission of medical therapy for a period of 1 week. Along with a comparable decrease in LV muscle mass, coronary reserve was improved after enalapril by 48%, after diltiazem by 48%, and after bisoprolol by 22%. It is possible that the observed increase in coronary reserve is related to the reversal of structural vascular abnormalities on the level of the coronary microcirculation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Prevention with vasoactive drugs]. 129 Feb 99

Treatment of chronic heart failure with ACE-inhibitors has greatly improved the prognosis. In addition to ACE-inhibitors, diuretics seem to be necessary to decrease mortality, whereas the importance of cardiac glycosides has not been demonstrated unequivocally. Nevertheless, modern treatment of chronic heart failure in all stages should be a combination of diuretics, digitalis, and ACE-inhibitors rather than a stepwise addition of drugs depending on the severity of the disease. An increased heart rate leads to increased myocardial O2-consumption, decreased O2-supply, ischemia, and reduced contractility. Betablocker-induced reduction of heart rate does, however, not necessarily improve symptoms or hemodynamic conditions. The optimal heart rate in large failing hearts is not known yet. Probably, it is dependent on the type and severity of myocardial disease or impairment. In this respect, the sarcoplasmatic release and uptake of Ca2+ plays the most important role in the disordered force-frequency-relation in chronic heart failure.
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PMID:[Clinical aspects of differential drug therapy of chronic heart failure]. 129 Mar 10

The role of NO-formation induced by accumulated endogenous bradykinin (BK) via local ACE-inhibition with ramiprilat (RT) or by adding BK exogenously was evaluated in cultured bovine aortic endothelial cells (BAEC) and in isolated rat hearts with post-ischaemic reperfusion injuries. Furthermore we used the n-octyl-ester of ramipril (RA-octil) which was shown to have no ACE-inhibitory action. In BAEC, ACE-inhibition by RT (1 x 10(-8)-1 x 10(-6) mol/l) or addition of BK (1 x 10(-8)-1 x 10(-6) mol/l) stimulated the formation of NO and prostacyclin (PGI2) as assessed by endothelial cyclic GMP- and 6-keto-PGF1a formation. Cyclic GMP and PGI2 synthesis was completely suppressed by the NO synthase inhibitor NG-nitro-L-arginine (L-NNA, 1 x 10(-5) mol/l) and by the B2 kinin receptor antagonist HOE 140 (1 x 10(-7) mol/l). RA-octil (1 x 10(-8)-1 x 10(-4) mol/l) did not affect endothelial cyclic GMP production in BAEC. In isolated working rat hearts subjected to local ischemia with reperfusion both RT (1 x 10(-8) mol/l) and BK (1 x 10(-9) mol/l) reduced the incidence and duration of ventricular fibrillation. In parallel myocardial function (left ventricular pressure, coronary flow) and metabolism (high energy rich phosphates) were improved showing a comparable fingerprint for RT and BK. Addition of L-NNA (1 x 10(-6) mol/l) or HOE 140 (1 x 10(-9) mol/l) abolished these protective effects of RT and BK. As in the BAEC studies RA-octil was without beneficial effects on the isolated ischaemic rat heart. The findings on BAEC show that inhibition of ACE localized on the luminal side of the vascular endothelium results in increased synthesis of NO and prostacyclin by local accumulation of endothelium-derived BK. Similar mechanisms may occur in the ischaemic rat heart leading to cardioprotection.
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PMID:ACE-inhibition induces NO-formation in cultured bovine endothelial cells and protects isolated ischemic rat hearts. 133 74

It has been known for a long time that systemic infusion of angiotensin II in patients with coronary artery disease or normal control subjects causes a marked increase in left ventricular end diastolic pressure (LVEDP) and systolic pressure (LVP) (1,2). In this setting angiotensin II produces a marked increase in afterload that makes it difficult to acknowledge possible local myocardial effects of the peptide. The studies (3-8) summarized in the present paper were designed to examine the physiological role of local cardiac angiotensin II generation and local bradykinin degradation on cardiac function in the normal and hypertrophied rat heart. Angiotensin I and angiotensin II, infused in isolated, well oxygenated, buffer perfused normal rat hearts, produced a mild increase in LVEDP with no change in systolic function (3). In contrast, in hypertrophied rat hearts, angiotensin I and angiotensin II caused a marked deterioration of diastolic function, increasing LVEDP from 10 to 25-37 mmHg on average (3,5). Preliminary evidence suggests that angiotensin II effects on diastolic function are mediated via a protein kinase C dependent pathway that might involve Na+/H+ exchange (4,5). When cardiac angiotensin converting enzyme was blocked by infusion of an ACE inhibitor prior and in parallel to angiotensin I infusion no changes in diastolic function were noted (6). Furthermore, ACE inhibition blunted the diastolic dysfunction during low flow ischemia in isolated hypertrophied rat hearts (7). This effect of ACE inhibition was even more remarkeable, since no exogenous angiotensin was infused in this experiment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cardiac angiotensin converting enzyme and diastolic function of the heart. 133 46

Restoration of coronary blood flow in the ischemic myocardium is absolutely needed to prevent irreversible cellular damage but on the other hand may have potentially hazardous consequences. Since thrombolysis during myocardial infarction is designed to salvage a maximal number of myocardial cells threatened by ischemia, a concommitant intervention which reduces cellular damage due to reperfusion will improve the net result of such procedure. The adjunctive use of ACE-inhibitors with thrombolytic therapy early during acute myocardial infarction offers theoretic advantages. This article summarizes the results indicating that ACE-inhibitors do play an important role in cardioprotection in the acute phase of myocardial ischemia followed by reperfusion. Probably, their effect on bradykinin breakdown is at least partly responsible for this effect.
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PMID:Early ACE-inhibition in myocardial infarction. Possible role of bradykinin. 146 86

In experimental ischemic dog heart with coronary-constriction, no increase of coronary blood flow, Max dP/dt or MVO2 with no change of kinin in arterial blood were exhibited. Following sympathetic nerve stimulation, remarkable increases of kinin in coronary sinus blood were observed with a significant elevation of left ventricular end-diastolic pressure and an augmented production of lactate from the heart as well as an ischemic change of ECG-ST. Infusion of kinin into the left main coronary artery resulted in no change in the mean systemic blood pressure, coronary blood flow, coronary vascular resistance, cardiac function, myocardial metabolism or ECG-ST in the control and coronary-constricted groups. These data suggest that kinin was released significantly from the ischemic heart, however, such a level of kinin has no significant effect on coronary circulation or myocardial metabolism. In ischemia-reperfusion rabbit hearts, no significant influence of the ACE inhibitors, captopril and ramiprilat, were observed. Species differences may be responsible for the beneficial role of ACE inhibitors in the limitation of infarct size in the dog hearts, possessing collateral flow, that are not seen in the rabbit heart with poor collateral flow.
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PMID:Activation of kinins on myocardial ischemia. 146 87

Left ventricular hypertrophy (LVH) constitutes a powerful independent risk factor in hypertensive heart disease. Although initially the wall stress, i.e., left ventricular afterload, remains normal, the coronary reserve is diminished due to disturbances in the microcirculation. This is also shown in the commonly present silent ischemia episodes in Holter monitoring. LVH also causes ventricular dilation and heart failure. Apart from systolic wall stress LVH is modulated by the trophic effects of the sympathetic nervous system and angiotensin II and genetic factors. Long-term antihypertensive treatment must therefore focus on regression of both LVH and the microvascular abnormalities. A step approach for the treatment of the LVH has been recommended on the basis of the experience of this working group with calcium antagonists and ACE inhibitors, whereas the place of beta-blockers is as yet unclear. Preliminary data indicate that coronary flow rescue can also be improved after chronic antihypertensive treatment.
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PMID:Therapeutic effect on left ventricular hypertrophy by different antihypertensive drugs. 153 67

Patients with hypertension requiring therapy frequently present with concurrent peripheral vascular disease (PVD). This situation must be taken into account for an optimum antihypertensive treatment. In general, in patients with PVD only a cautious and gradual lowering of the blood pressure is recommended, since the decrease in poststenotic perfusion pressure may accentuate the symptoms of occlusive disease. In intermittent claudication--the most frequent manifestation of occlusive disease beta--receptor blockers today are no longer considered to be contraindicated. In the presence of critical ischemia of the legs (pain at rest and/or necroses) beta blockers should only be given with extreme caution. The agents of choice are calcium antagonists, ACE -inhibitors as well as alpha blockers and some newer vasodilating substances (e.g. Carvedilol). Conventional diuretics show disadvantages. An slightly elevated blood pressure in critical leg ischemia helps to improve the poststenotic perfusion of the affected limb. Antihypertensive treatment should not be instituted in patients whose systolic blood pressure is lower than 160 mmHg.
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PMID:[Antihypertensive therapy in arterial occlusive disease]. 168 38

Local inhibition of angiotensin-converting enzyme (ACE, kininase II) produces both attenuation of angiotensin (Ang) II generation and bradykinin (BK) degradation. To delineate the participation of BK in the cardioprotective actions of ACE inhibitors, experiments were performed in rats and dogs with cardiac ischemia-reperfusion injuries. (I) In rat isolated perfused working hearts with regional myocardial ischemia, BK in concentrations as low as 1 X 10(-9) M increased coronary flow (CF) and reduced the incidence and duration of reperfusion ventricular fibrillation (VF). In addition, enzyme activities of lactate dehydrogenase (LDH) and creatine kinase as well as lactate output were decreased in the venous effluent of BK-perfused hearts, which also showed improved cardiodynamic and metabolic parameters. Even concentrations of BK lower than 1 X 10(-10) M, which were without influence on coronary flow, exerted comparable beneficial metabolic effects connected with reduced incidence and duration of VF. Combined perfusions with threshold concentrations of BK (1 X 10(-12) M) and the ACE inhibitor ramiprilat (2.58 X 10(-9) M), which were ineffective given alone, resulted in a marked cardioprotective effect. Perfusion with Ang II (1 X 10(-9) M) aggravated reperfusion arrhythmias and worsened myocardial metabolism. BK perfusion prevented this deterioration in a concentration-dependent manner, whereas the Ang II receptor antagonist saralasin was only marginally effective. The BK antagonist D-Arg-[Hyp2, Thi5,8, D-Phe7]-BK (1 X 10(-5) M) completely abolished the cardioprotective effects of BK or the ACE inhibitor. However, higher concentrations of BK (1 X 10(-7) M) or ramiprilat (2.58 X 10(-5) M) competitively reversed these properties of the BK antagonist. (II) In anesthetized dogs, BK was infused into the coronary artery in a dose of 1 ng/kg/min during occlusion (90 min) and reperfusion (30 min) of the left descending coronary artery (LAD)--a dose without effects on cardiovascular parameters. In line with the findings in isolated ischemic rat hearts, BK infusion reduced LDH activities and lactate concentrations in the coronary sinus blood, whereas myocardial tissue levels of glycogen and energy-rich phosphates were increased in the infarcted area. The cardioprotective effects produced by perfusion with BK or by reduction of BK degradation through local interference with ACE favor a role for BK in ischemia-reperfusion injuries in rats and dogs.
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PMID:Local inhibition of bradykinin degradation in ischemic hearts. 169 70


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