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)

In Langendorff-perfused rat hearts, the perfusion pressure was reduced from 100 cm H2O to 20 cm H2O for 30 minutes to produce a model of global ischemia with a residual oxygen uptake. The release of lactate dehydrogenase (LDH) and the occurrence of ventricular arrhythmias during reperfusion were dependent on the substrate. Glucose-perfused hearts had the highest rates of glycolytic ATP production (2.5 mumol/g per min) during ischemia with normal contents of tissue cyclic adenosine 3',5'-monophosphate (cAMP) and, during reperfusion, the release of LDH was lowest and severe ventricular arrhythmias did not occur. In pyruvate-perfused hearts, glycolysis was inhibited during ischemia, the rate of production of glycolytic ATP was only 0.5 mumol/g per min. and tissue cAMP doubled; during reperfusion, LDH release was 14-fold higher and ventricular arrhythmias were more severe. Total tissue contents of ATP and phosphocreatine were similar in glucose- and in pyruvate-perfused hearts. In hearts perfused with acetate, there was virtually no glycolytic ATP synthesized during the last 5 minutes of ischemia and cAMP increased further. Acetate- and palmitate-perfused hearts showed greatest release of LDH and had severest arrhythmias during reperfusion, suggesting that it was the metabolic and not the detergent effects of palmitate that were operating. Lipolysis was not a major factor in the cause of reperfusion LDH release. A role of glycolytic ATP in the maintenance of membrane integrity is postulated.
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PMID:Effects of substrates on tissue metabolic changes in the isolated rat heart during underperfusion and on release of lactate dehydrogenase and arrhythmias during reperfusion. 20 59

The eventual depth of tissue necrosis after burning is not immediately apparent. In all burn wounds, there exists a zone of stasis which shows progressive microvascular deterioration. These progressive changes have been prevented by methylprednisolone acetate, indomethacin, and ASA. All of these agents are known to inhibit prostaglandin synthesis. These data suggest that prostaglandins have a role in the progressive dermal ischemia after thermal trauma and that their effect can be prevented by specific antiprostaglandins.
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PMID:Preventing the prostaglandin effect on dermal ischemia in the burn wound. 40 Dec 78

The relationship between energy metabolism and the extent of irreversible ischemic damage was examined in an isolated perfused working rat heart. The amount of cardiac work recovered after reperfusion of hearts exposed to severe global ischemia was dependent upon both the duration of ischemia and the type of substrate provided (either 5 mM glucose or 5 mM glucose + acetate). There appear to be two distinct phases in the ability to recover mechanical function in the reperfused ischemic heart. The second phase corresponds to the onset of severe irreversible tissue damage. Irreversible mitochondrial damage was not found to correspond with the onset of heart failure since the ATP/ADP ratio remained constant in the reperfused myocardium. Furthermore, there does not appear to be a direct correlation between the total ATP content and the extent of irreversible damage, either during ischemia or following reperfusion. However, the total adenine nucleotide content during ischemia showed dramatic changes which correspond temporally with the initiation of the second phase of damage. The observation that the adenine nucleotide pool becomes further depleted during reperfusion suggests that alterations in the salvage pathway for adenine nucleotide synthesis have occurred. Loss of adenine nucleotides appears to be an excellent marker for irreversible heart failure. Acetate provides some protection the the ischemic myocardium. The mechanism by which acetate mediates this protective effect is discussed.
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PMID:Relationship between adenine nucleotide metabolism and irreversible ischemic tissue damage in isolated perfused rat heart. 44 6

The effect of preliminary administration of alpha-tocopherol acetate (1 mg/kg) and sodium selenite (1 mg/kg) on RNA synthesis rate and changes in the macroergic content in ischemic myocardium was studied. It was shown to be conducive to ATP level maintenance after 30- and 60-minute heart ischemia. A statistically significant accumulation of RNA by the myocardium following I-hour ischemia as well as this polynucleotide synthesis activation were recorded. Preservation of the energetic resources by the cell along with RNA metabolism returning to normal contributes to inhibiting the emergence of irreversible cell damage and increases regenerative potentialities of the myocardium.
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PMID:[Effect of alpha-tocopherol acetate and sodium selenite on the change in ATP content and the RNA synthesis rate in the ischemic myocardium]. 44 4

Shock was induced in 537 rats by exteriorization of the intestines and occlusion of the superior mesenteric circulation for 1 hour. After 1 hour of this intestinal ischemia shock, oxygen consumption (VO2) decreased to half of the preexperimental values. When no infusion was given, the survival rate at 24 hours was 22%; this was correlated with the degree of restoration of VO2 at 1 hour after shock. VO2 and survival rate improved with infusion of albumin, dextran 40, and dextran 40, and dextran 70. With increasing doses of colloids, both VO2 and survival rate increased; the optimal effect was at the dose of 2 g/kg body weight. When no other therapy was given, colloids at concentrations of 3.5 or 6% solutions had a better effect on survival than the 10% solution. Colloids were more effective than Ringer's acetate when the latter was given in the same volume and up to three times the volume of the colloids.
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PMID:Oxygen consumption and recovery from surgical shock in rats: a comparison of the efficacy of different plasma substitutes. 47 54

One percent methylprednisolone acetate was evaluated as a pharmacologic agent in the prevention of dermal ischemia following burning. Standardized partial thickness burns were inflicted on guinea pigs. Burned guinea pigs were separated into five groups; one was treated with topical steroid, one with systemic steroid, one with both, one with emollient base without steroid, and one served as an untreated control. Histology and depth of dermal ischemia were evaluated by india ink perfusion technique. Untreated controls showed progressive dermal ischemia with complete absence of india ink-filled vessels in the dermis by 24 hours. Topical steroid alone improved dermal perfusion as suggested by relative levels of india ink filling. Topical steroid in the dosage used does not potentiate infection in standard burn wound sepsis models. Preservation of dermal appendages was seen secondary to improved dermal microcirculation with a ninefold increase in hair follicles in treated guinea pigs compared with controls.
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PMID:Prevention of dermal ischemia after thermal injury. 64 24

Fibroblast growth factors (FGF) and type beta-1 transforming growth factor (TGF beta 1) are pleiotropic regulatory peptides which are expressed in myocardium in a precise developmental and spatial program and are up-regulated, in the adult heart, by ischemia or a hemodynamic burden. The accumulation of trophic factors after aortic banding supports the hypothesis that autocrine or paracrine pathways might function to mediate, in part, the consequences of mechanical load. Our laboratory has demonstrated that cardiac muscle cells are targets for the action of peptide growth factors and, more specifically, that modulation of the cardiac phenotype by basic FGF (bFGF) and TGF beta 1 strongly resembles the induction of fetal cardiac genes--including skeletal alpha-actin (SkA), beta-myosin heavy chain, and atrial natriuretic factor--which are characteristic of pressure-overload hypertrophy. Unexpectedly, and despite effects like those of bFGF on five other cardiac genes, acidic FGF (aFGF) was found to repress, rather than stimulate, SkA transcription in neonatal cardiac muscle cells. The proximal 200 nucleotides of a heterologous SkA promoter were sufficient for basal tissue-specific transcription, for induction by bFGF, and for inhibition by aFGF. Thus, both positive and negative regulation by peptide growth factors can be localized to the proximal SkA promoter. Full promoter activity required each of three CC[A/T]6GG motifs similar to the serum response element (SRE) for activation of the c-fos proto-oncogene, as previously shown for SkA transcription in a skeletal muscle background. The most proximal SRE, SRE1, was sufficient in the absence of other SkA promoter sequences for efficient tissue-specific expression in cardiac myocytes (versus cardiac fibroblasts), and was stimulated by bFGF to the same extent as the full-length promoter and endogenous gene. Despite its ability to repress the SkA promoter, aFGF had no significant effect on SRE1. Both FGFs up-regulated the canonical fos SRE, to a comparable degree. Thus, SRE1 can discriminate between signals generated in cardiac myocytes by bFGF and aFGF. In cardiac myocyte extracts, two predominant proteins contact SRE1: serum response factor (SRF) and a second protein, F-ACT-1. Thus, serum response factor and F-ACT-1 are candidate trans-acting factors for basal transcription of the SkA gene in cardiac muscle cells and for induction of SkA by bFGF and, potentially, other trophic signals.
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PMID:Growth factors, growth factor response elements, and the cardiac phenotype. 128 69

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


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