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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of ischemia on renal blood flow (RBF) in the rat has been an unsettled question. This study used a totally extractable indicator, radioactive microspheres, with a reference arterial sample, to study RBF quantitatively 10 and 60 min after 1 h of unilateral renal artery clamping in anesthetized, heparinized rats. The results indicate that after release of the arterial clamp, the kidney is enlarged and exhibits an increase in renal vascular resistance. RBF to the contralateral non-ischemic kidney is not different from that of a time-control series.
Nephron 1978
PMID:Effect of ischemia on renal blood flow in the rat. 67 90

Forms, dynamics of and relationships between necrotic changes in the skeletal muscles in the early period of the crush syndrome, following 9-hour compression of the soft tissue of the dog's thigh and 2 -- 7 hours after removal of the press are considered. Two interdependent forms of necrosis of muscles have been established -- diskoid and coagulative. Electron-microscopy studies showed that discoid necrosis of muscular fibres began with the lysis of the myofilaments of isotropic disks and Z-strips with subsequent destruction of myofibrils and outcome into myolosis. The peculiar feature of this form of necrosis was nearly complete absence of lysosomes. In a light microscope discoid necrosis was revealed as clear-cut transversed streaky fibres. Morphologically, coagulation necrosis was manifested on the ultrastructural level by formation of myofilic conglomerates consisting of overcontracted myofibrils, these being subjected to gradual fragmentation and splitting by hydrolases of leukocytes and macrophages. Discoid necrosis predominated in the muscles prior to the removal of the press and apparently developed because of ischemia. Coagulation necrosis of myofibrils was observed mostly following re-vascularization and might be one of outcomes of discoid necrosis.
 ...
PMID:[Dynamics of necrotic changes in skeletal muscle in the prolonged crush syndrome]. 101 93

We investigated the incidence of painless (silent) myocardial ischemia, manifested as S-T segment deviation, by Holter ECG monitoring in patients with chronic renal failure undergoing regular hemodialysis. Forty-five patients underwent Holter ECG monitoring for a continuous 48-hour period covering dialysis and the intermediate period of everyday activity at home. ECG criteria for ischemia were found in 15.5% of patients mainly during and immediately after dialysis with a simultaneous increase of R,S,R + S amplitude. There was no correlation of S-T segment deviation with the existence of cardiac dysfunction and coronary artery disease proved by hemodynamic and angiographic studies. It is concluded that hemodialysis itself seems to play an important role in the genesis of the above ECG findings, possibly by means of serum K and Mg changes.
Nephron 1992
PMID:Painless myocardial ischemia in chronic hemodialysed patients: a real event? 155

Larger NMR magnets with relatively high field strengths have become available recently, allowing the application of magnetic resonance spectroscopy (MRS) in larger mammalian organs. The aim of this study was to develop and test a new and simple kidney perfusion model from slaughterhouse swine using a new 4.7-tesla/40-cm diameter system, with the intention behind to provide a human-like mammalian experimental kidney perfusion model, and to avoid sensitive in vivo animal experiments on higher-developed mammalians, 35 pig kidneys obtained 10-15 min post mortem were studied to evaluate and define conditions for optimum metabolic preservation with the following perfusion protocols: (1) immediate plegia with cold Collins solution, 1-3 h cold storage, P-31 MRS; (2) immediate plegia, 1-3 h cold storage, blood reperfusion, P-31 MRS; (3) immediate blood reperfusion, plegia, 1-3 h cold storage, blood reperfusion, P-31 MRS; (4) immediate blood reperfusion, plegia, 24 h cold storage, blood reperfusion, P-31 MRS, P-31 MRS at 81 MHz with a double-tuned surface coil yielded the following results: [table: see text] Blood flow showed a weak correlation with beta-ATP/inorganic phosphate in protocols 3 and 4 of r = 0.64. Repeated reperfusion and ischemia experiments of this model allowed the on-line observation of the metabolic response of the energy phosphate pattern for several hours. In conclusion, slaughterhouse-harvested swine kidneys lend themselves to a simple, low-cost in vitro perfusion model, provided they are reperfused with arterial blood immediately after harvesting.(ABSTRACT TRUNCATED AT 250 WORDS)
Nephron 1991
PMID:Application of P-31 nuclear magnetic resonance spectroscopy to a new experimental kidney perfusion model using cadaveric porcine kidneys from slaughterhouse. 201 76

Recently we reported that maintaining rats on restricted dietary protein regimens prior to renal ischemia will significantly improve postischemic survival rates. This effect required a week or more of maintenance on a restricted protein diet prior to the renal insult and appeared to be independent of the postischemic dietary protein regimen. The present study was designed to evaluate the role of systemic toxicity in this protection. Adult male Sprague-Dawley rats were pair-fed by weight on restricted or high isocaloric protein diets for 8-10 days prior to 45 min of renal ischemia induced by renal pedicle clamping. When placed on a normal dietary protein regimen immediately following ischemia, the rats preconditioned to restricted dietary protein exhibited significantly less acidosis, less hyperkalemia, lower blood urea nitrogen values, and improved survival rates compared with rats preconditioned on a high dietary protein regimen. In order to separate the possible effects of prior dietary protein regimen on acute tubular necrosis suffered during renal ischemia from its effects on the uremic response, bilateral nephrectomies were performed on rats preconditioned for 14 days to low, normal, and high dietary protein regimens. Although all of the rats were placed on the same dietary protein regimen immediately following bilateral nephrectomy, those that had previously been on a lower dietary protein regimen exhibited a significantly reduced uremic response and lived longer. These findings indicate that dietary protein regimen prior to renal ischemia is a risk factor which can have a significant lingering effect on the severity of postischemic systemic toxicity.
Nephron 1990
PMID:Dietary protein regimen prior to renal ischemia significantly affects the postischemic uremic response. 237 Sep 27

The present study was carried out to examine the effect of potassium depletion in rat kidneys subjected to a temporary ischemic event produced by clamping of left renal artery. The postischemic kidneys of rats on a normal diet with adequate potassium intake showed an increase in H2O, Na and K excretion, with no change in inulin clearance whereas significant differences were found in potassium-deprived rats. Potassium depletion was brought about by dietary K deprivation for 10 days. K-depleted rats (serum K = 2.5 +/- 0.1 mEq/l) had a decrease in inulin clearance of the postischemic kidney from 1.01 +/- 0.10 to 0.43 +/- 0.05 ml/min (p less than 0.01), and a greater increase in fractional excretion of H2O, Na and K when compared to normal rats. The postischemic kidney from both normal and hypokalemic rats showed a decrease in Na-K-ATPase of the inner stripe of the outer medulla. These data indicate that short-term ischemia produces polyuria, increases natriuresis and kaliuresis, associated, at least in part, with a decrease in Na-K-ATPase in the inner stripe of the outer medulla (probably the thick ascending limb of Henle) and that K depletion potentiates ischemic renal failure.
Nephron 1989
PMID:Effect of potassium depletion on ischemic renal failure. 253 74

Two cases of renal segmental infarction and 1 case of renal patchy ischemia demonstrated by magnetic resonance imaging (MRI) are reported. MRI of renal infarction in two renal grafts following surgical ligation revealed an area of noncorticomedullary differentiation and an area with a low signal intensity. Renal ischemia in 1 patient with acute renal dysfunction with severe loin pain and patchy renal vasoconstriction was visualized as an ill-defined focus of low signal intensity in the renal cortex, indicating a long T1 relaxation time. Delayed wedge-shaped contrast enhancement was demonstrated on CT scan in the same area. The common finding in renal infarction and ischemia in our cases was the area of low signal intensity on MRI.
Nephron 1989
PMID:Magnetic resonance imaging in renal infarction and ischemia. 264 69

Three healthy adult males developed acute renal failure following cocaine abuse. Muscle pain, tenderness, elevated levels of serum muscle enzymes, heme-positive urine and the presence of pigmented granular casts in urine all indicated occurrence of rhabdomyolysis. One of them developed acute compartmental syndrome of the left leg and required emergency fasciotomy. The course of renal failure and fast recovery were suggestive of acute tubular necrosis in all 3 patients. A possible role of cocaine in the aggravation of renal and/or muscle ischemia has been speculated.
Nephron 1989
PMID:Acute renal failure following cocaine abuse. 231 44

The effects of chronic ethanol ingestion on the rat kidney were studied. Rats were fed a liquid diet containing ethanol for 5 weeks to induce chronic alcoholism. Renal ischemia was introduced by clamping the renal artery and vein either for 10 or 20 min. The glomerular filtration rate (GFR) and the renal blood flow (RBF) were determined by using I125-iothalamate and I131-iodohippurate. In the absence of renal ischemia, there were no significant differences in the renal function between nonalcoholic rats (n = 5) and alcoholic rats (n = 5): 380 +/- 30 vs. 403 +/- 27 microliters/min/100 g body weight (BW) in GFR, and 3.1 +/- 0.1 vs. 3.1 +/- 0.2 ml/min/100 g BW in RBF. The recovery of GFR measured 2 h following 10-min renal ischemia in both groups was not significantly different; the values returned to 340 +/- 40 microliters/min/100 g BW (nonalcoholic rats) and 246 +/- 22 microliters/min/100 g BW (alcoholic rats), respectively. The changes of RBF following 10 min ischemia were also similar in both groups. However, the effects of alcoholism on the renal function became apparent when animals were subjected to more prolonged renal ischemia. In nonalcoholic rats (n = 5), GFR and RBF measured 2 h following 20 min renal ischemia were 245 +/- 51 microliters/min/100 g BW and 2.5 +/- 0.4 ml/min/100 g BW, whereas in alcoholic rats (n = 5) the GFR and RBF were significantly decreased to 93 +/- 15 microliters/min/100 g BW and 1.1 +/- 0.2 ml/min/100 g BW, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Nephron 1989
PMID:Kidneys of chronic alcoholic rats are more vulnerable to ischemic insult. 281 70

In essential hypertension ventricular function is determined primarily by the degree of hypertrophy (myocardial factor) and by the organic complications in the coronary artery (coronary factor). Ventricular function is inversely correlated with ventricular size and systolic wall stress, inasmuch as ventricular function diminishes when these two variables increase. Even the young hypertensive heart of normal size with no angiographic abnormalities appears to be prone to ischemia, because the coronary reserve is seriously limited even in the absence of coronary stenosis. Unlike ventricular distensibility, myocardial compliance may be normal even in the presence of pronounced myocardial hypertrophy. As myocardial compliance decreases, systolic wall stress increases and ventricular function is reduced. The hypertensive heart, the most common form of an irregular hypertrophy of the ventricular wall, is found in 14% of such cases. Analysis of the degree of hypertrophy shows that the hypertrophy can be inappropriately high (high mass-to-volume ratio, reduced wall stress), appropriate, or inappropriately low (normal mass-to-volume ratio, increased wall stress). Coronary reserve is reduced even in hypertensive hypertrophy without evidence of coronary artery disease. MVO2 per mass unit was directly correlated with systolic wall stress per cross-sectional area of the left ventricular wall. It is concluded that the appropriateness of left ventricular hypertrophy, as a result of mass-to-volume ratio and stress, is a major determinant of left ventricular performance, of coronary blood flow, and of myocardial oxygen consumption. Pharmacotherapeutical means of reversing cardiac hypertrophy (prazosin, clonidine, enalapril, and nifedipine) were analyzed in concentrically, as well as eccentrically, hypertrophied left ventricles. Regression of cardiac hypertrophy, i.e. therapeutic intervention on a critical precursor of hypertensive congestive heart failure, can be obtained by various antihypertensive agents. Prazosin, calcium channel blockers and angiotensin-converting enzyme inhibitors as well as a combined treatment regimen using alpha-receptor blockers together with diuretics and vasodilators can all induce regression of hypertrophy associated with an improvement in left ventricular function. Moreover, an improved coronary reserve may reduce the ischemic risk of the hypertrophied myocardium. However, not all antihypertensive drugs seem equally effective in bringing about coronary regression of left ventricular hypertrophy. No regression or little regression has been found with diuretic monotherapy despite a satisfactory reduction in blood pressure.(ABSTRACT TRUNCATED AT 400 WORDS)
Nephron 1987
PMID:Comparative analysis of cardiac function, geometry, energetics and coronary reserve in hypertensive heart disease. 296 4


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