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)

Densitometric studies show that the large flow measurement errors and inability to obtain reproducible densitometer calibrations reported with indocyanine green (ICG) in nearly isotonic saline may have arisen from two sources: (a) slowed optical stabilization, and (b) sedimentation of dye aggregates formed in the salt "solutions" of ICG, both of which are avoidable by preparing the dye in water. The assumptions of the widely used regional blood flow measurement technique using radionuclide-labeled microspheres are described. Simultaneous injection of 8mu and 15mu microspheres in turkeys and in dogs demonstrated the existence of at least 8 mu arteriovenous communications (AVCs) in the stomach and intestine, not previously described by this technique, which, in addition to their physiologic functions, may play a role in production of acute gastric mucosal ischemia and erosions. Similar AVCs, producing a lesser degree of "shunting," were also found in the heart. Loss of 8 mu relative to 15 mu microspheres continued with time in the gastrointestinal circulation.
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PMID:Recent developments in the measurement of cardiac output and regional blood flow using indocyanine green and microspheres. 32 18

Renal handling of sodium was studied in five dogs where an end-to-side portacaval fistula was constructed prior to the induction of cirrhosis with DMN. Such a model permits the effects of cirrhosis to be studied separately from the consequences of portal hypertension. Three control animals without cirrhosis maintained normal liver and kidney function and remained in sodium balance for as long as 8 weeks following surgery. In the five cirrhotic dogs, urinary sodium retention preceded ascites formation and was independent of hyperaldosteronism, hypoalbuminemia, hepatic ischemia, or decreased renal perfusion. Portal venous pressure remained normal in all cirrhotic dogs, and the splanchnic area remained free of venous collaterals. Plasma volume expansion also preceded ascites formation, and this variable increased by 8.4% (p less than 0.05) following 6 days of sodium retention. These temporal relationships between sodium retention, expanded plasma volume, and ascites formation are similar to those observed in ordinary cirrhotic dogs previously studied in this laboratory. Total plasma volume increased by 13.2% (p less than 0.05) when measured during the ascitic phase of cirrhosis. However, when the splanchnic and nonsplanchnic ("effective") components of plasma volume were measured by an exclusion technique, the ratio of these components to total plasma volume was not different from that observed in normal dogs. Thus no preferential consignment of retained salt and water had occurred. We conclude that urinary sodium retention in cirrhotic dogs occurs independently of portal hypertension or augmented splanchnic vascular capacity and is associated with expansion of the effective plasma volume, even though ascites is present.
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PMID:Renal sodium retention and ascites formation in dogs with experimental cirrhosis but without portal hypertension or increased splanchnic vascular capacity. 62 53

We studied the effect of different chronic (3-4 weeks) dietary salt intakes on intrarenal hemodynamics of normal and mercury-intoxicated rats. Cardiac output (CO), total renal blood flow (RBF), and the zonal perfusion rate in the outer cortex (OC) and inner cortex (IC) were measured by the radioactive microsphere method. The distribution of cortical blood flow was calculated as the distribution index (DI), which reflects the ratio OC/IC. Rats were placed on a high salt diet (group I), intermediate salt diet (group II), or low salt diet (group III). For each group control rats (subgroup A) and mercury-intoxicated rats (subgroup B) were studied. No effect of the different salt intakes on the DI could be detected. The DI in group IA was 2.35 +/- 0.14; in IIA, 2.40 +/- 0.16; and in IIIA, 2.38 +/- 0.09 (P greater than 0.05). After mercury injection RBF changed from 5.32 +/- 0.36 ml/g.min(-1) (IIA) to 3.31 +/- 0.20 ml/g.min(-1), IIB and from 4.32 +/- 0.11ml/g.min(-1) (IIIA) to 1.98 +/- 0.10 ml/g.min(-1) (IIIB) P less than 0.01). The DI was lowered to 1.53 +/- 0.06 (IIB) (P less than 0.05) and to 1.16 +/- 0.10 (IIIB) (P less than 0.01). In both IIB and IIIB a marked elevation of the blood urea was noted (IIB = 97 +/- 9 MG/100 ML AND IIIB = 182 +/- 25 mg/100 ml). In group IB no effect on RBF, OC, IC, or DI could be observed (for all values, P greater than 0.05) despite similar histological renal lesions. Group IB rats also had normal blood urea levels (31 +/- 6 mg/100 ml;P greater than 0.05). We conclude (1) that variations in dietary salt intake appear to have no detectable effect on the intracortical blood flow distribution; and furthermore (2) that the mercury-induced acute renal failure (ARF) is characterized hemodynamically by a total renal and preferential outer cortical ischemia and that chronic salt loading prevents the ARF while preserving normal renal perfusion.
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PMID:Effect of variation in dietary NaCl intake on total and fractional renal blood flow in the normal and mercury-intoxicated rat. 96 34

A possible protective effect of glucocorticoids on the ischemic myocardium was investigated in in situ dog hearts subjected to regional ischemia and in isolated rat hearts subjected to global ischemia. In the whole-animal preparation, the left anterior descending coronary artery (LAD) was occluded for 3 hours, or for 2 1/2 hours followed by 30 minutes of reperfusion. Dexamethasone phosphate was randomly administered (20 mg. per kilogram intravenously) after 15 minutes of ischemia. Its effects were studied on the following: (1) myocardial cell membrane integrity, using electron microscopic examination of tissue biopsies treated with colloidal lanthanum; (2) myocardial water content, measuring the wet/dry weight of myocardial tissue; (3) ischemic injury, by a count of fuchsinophilic cells at light microscopy. In isolated rat hearts, ischemia was produced by a 60 per cent reduction of coronary flow. Randomized hearts were perfused for 2 hours with dexamethasone, 15 mg. per milliliter in buffered salt solution. Study included determination of tissue water content and coronary vascular resistance. Lanthanum was confined to the extracellular spaces in normal dog myocardium, but it was found all intracellularly after 3 hours of ischemia or after reperfusion. This was associated with morphologic changes characteristic of irreversible cell injury. In the hearts treated with dexamethasone, lanthanum remained excluded from the cells, water content was less (p less than 0.005), and fuchsinophilia less severe (p less than 0.005). Likewise, water content was less (p less than 0.005) and the increase in coronary vascular resistance resulting from ischemia less severe (p less than 0.005) in the dexamethasone-treated isolated rat hearts. Thus dexamethasone administered in pharmacologic doses, early, appeared to stabilize the cell membrane, limit myocardial edema, and reduce the severity of injury, both during ischemia and upon reperfusion.
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PMID:Glucocorticoid protection of the myocardial cell membrane and the reduction of edema in experimental acute myocardial ischemia. 96 99

Studies on animals implicating reflux of bile salts in formation of "stress ulcer" often are suspect because of the inordinately high intragastric concentrations of bile salts used to induce experimental acute gastric mucosal damage. We studied reflux of bile salt in 11 patients after operation. Nine refluxed bile salts in a mean intragastric concentration of 1.87 +/- 0.24 mM. (range, 0.34 to 4.88 mM.). In the present study, therefore, the ulcerogenic potential of physiologic concentrations of bile salts was evaluated. With use of vascularized, chambered canine gastric mucosa, groups of animals were studied during three consecutive periods. Group A = topical acid test alone (ATS) during periods 1, 2, and 3; Group B = (1) ATS, (2) ATS, (3) ATS + vasopressin (VP = 0.1 U per Kg.-min. via the splenic artery); Group C = (1) ATS, (2) ATS + topical 1 mM. sodium taurocholate (TC), (3) ATS + 1 TC + VP; Group D = (1) ATS, (2) ATS + 2 TC, (3) ATS + 2 TC + VP; Group E = (1) ATS (2) ATS + 5 TC, (3) ATS + 5 TC + VP. Parameters evaluated were (1) net fluxes H+, Na+; (2) electrical potential difference (PD); (3) clearance of aminopyrine, a measure of mucosal blood flow (MBF); and (4) formation of lesions, graded zero to six by an independent observer who used photographs. In nonischemic mucosa, bile salts produced no ulcers, a significant concentration-dependent increase in H+ "back diffusion" and fall in PD, and a noncentration-dependent increase in MBF. In ischemic mucosa, the combination of topical acid, topical bile salts, and mucosal ischemia was acutely ulcerogenic. The severity of mucosal injury was dependent on the concentration of bile salt (y = 0.108 + 1.53x, r = 0.90, p less than 0.01). These data indicate that acute mucosal damage occurs in the presence of physiologic concentrations of bile salt, i.e., those routinely found in the gastric contents of postoperative patients.
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PMID:Acute gastric mucosal ulcerogenesis is dependent on the concentration of bile salt. 127 70

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

Zinc is a potent inducer of the 72 kD heat shock protein (HSP72). In brain, pathological conditions such as ischemia and seizures increase extracellular zinc. The present study examines the effect of zinc on HSP72 expression in rat primary cortical astrocyte culture. Astrocytes were grown to confluence and exposed to zinc chloride in CO2-equilibrated Earle's buffered salt solution. Expression of HSP72 was examined using immunocytochemistry. HSP72 was induced with zinc concentrations of 5 to 100 microM after 4 h exposures, or 200 to 300 microM after 15 min exposures. At the lower concentrations expression occurred in small clusters of contiguous cells. At concentrations high enough to cause cell death, HSP72-positive astrocytes formed a continuous margin around patches of dead cells. These patterns of HSP72 expression are similar to the patterns seen after cerebral ischemia in vivo. Exposure to zinc at 100 microM for 4 h or 400 microM for 15 min caused greater than 90% cell death. Increases in extracellular zinc may contribute to HSP72 induction and astrocyte death under ischemia and other pathological conditions in brain.
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PMID:Zinc toxicity and induction of the 72 kD heat shock protein in primary astrocyte culture. 133 69

We evaluated the effectiveness of L-arginine mono(2-mercaptoethanesulfonate) (argimesna) to limit the extent of myocardial damage resulting from 60 minutes of severe ischemia followed by 30 minutes of reperfusion in the Langendorff-perfused rabbit heart. Argimesna is a sulfhydryl group containing molecule which has no effect on glutathione status or on the total thiol pool. The effects of 10(-6) M argimesna were compared with those of 10(-6) M L-arginine and of 10(-6) M sodium salt of 2-mercaptoethanesulfonate (mesna). Pretreatment of the hearts with 10(-6) M argimesna resulted in marked myocardial protection, measured in terms of improved recovery of developed pressure (p less than 0.01), reduced release of creatine kinase (p less than 0.01), maintenance of mitochondrial function and increased stores of ATP on reperfusion (p less than 0.01). On reperfusion less oxidative stress developed, as indicated by less accumulation of oxidized glutathione (p less than 0.01). These effects were specific for argimesna; no significant protection could be found for mesna and L-arginine. The beneficial effects of argimesna could not be explained by hemodynamic differences or effects on anaerobic metabolism. Neither is it likely that argimesna acts as a free radical scavenger at the concentrations employed. The protection may be achieved by maintenance of -SH groups during ischemia and reperfusion.
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PMID:The effects of L-arginine mono(2-mercaptoethanesulfonate) on the ischemic and reperfused heart. 142 Sep 54

The anti-ischemic effect of a 4% proxanol solution (intravenous injection in a dose of 10 ml/kg 60 min after occlusion) was compared with that of a salt solution in experimental acute ischemia of dog myocardium, induced by partial occlusion of the anterior descending branch of the left coronary artery. Overall estimation of the effect of SAS infusion has demonstrated that this drug has a beneficial effect on hemorheology (decreases blood viscosity and vascular resistance, increases coronary blood flow), stabilizes oxygen supply of the myocardium and lowers the extent of its ischemia-induced damage (eliminates ST segment depression). However, the cardiodepressive action of proxanol does not allow for compensation of the ischemia-induced decrease in myocardial contractility and pump function of the heart.
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PMID:[The effect of the surface-active substance proxanol on the ischemic myocardium]. 142 46

The effects of L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8,12-trimethyltridecyl)-2H-1-benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1, CAS 127061-56-7), a new compound for ischemia-reperfusion injuries, on lipid peroxidation and phospholipase A2 activity were studied in vitro using rat brain homogenates and human plasma. EPC-K1 inhibited phospholipase A2 activity in human plasma in a concentration-dependent manner (IC50 = 7.3 x 10(-4) mol/l), whereas a mixture of alpha-tocopherol and ascorbic acid did not exhibit this effect. In rat brain homogenates, EPC-K1 also inhibited lipid peroxidation in a concentration-dependent manner (IC50 = 2.3 x 10(-6) mol/l). alpha-Tocopherol was less active than EPC-K1. These properties of EPC-K1 suggest that EPC-K1 may prove useful in the treatment of ischemia-reperfusion injuries.
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PMID:In vitro studies on the influence of L-ascorbic acid 2-[3,4-dihydro- 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6yl-hy drogen phosphate] potassium salt on lipid peroxidation and phospholipase A2 activity. 144 71


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