Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0920646 (renal ischemia)
 2,515 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of ketanserin (Kt) has been analyzed during the development of two-kidney-two-clip (2k-2c) renovascular hypertension in the rat. Male Wistar rats were divided into four experimental groups: (1) clip Kt (ClKt) (n = 12)--A silver clip (0.25 mm width) was placed in each renal artery 3 days after beginning the administration of Kt (10 mg/kg/day) in the drinking water; (2) sham Kt (ShKt) (n = 13)--Similar to group 1, but the clips were placed in, and immediately removed from, the renal arteries; (3) untreated clip (UCl) (n = 10)--Similar to group 1, but the rats drank water; (4) untreated sham (USh) (n = 10)--Similar to group 2, but the rats drank water. Blood pressure (BP) was measured before surgery and was followed weekly for 7 weeks. At the end of this period, blood and cerebrospinal fluid (CSF) samples were obtained in all the animals. Plasma renin activity (PRA) and plasma and CSF angiotensinogen concentration (AoC) were evaluated. The results have shown that Kt partially inhibited the increase in BP induced by bilateral renal ischemia (BP: UCl rats 180.5 +/- 12.4 versus ClKt rats 149.8 +/- 5.1 mm Hg; p less than 0.01; USh rats 116.7 +/- 3.7; ShKt rats 114.4 +/- 5.0 mm Hg). PRA was similar in hypertensive and control rats whether or not they had received Kt. AoC in plasma was decreased in clipped treated and untreated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Chronic administration of ketanserin and the development of two-kidney-two-clip Goldblatt renovascular hypertension in the rat. 244 74

The effect of atrial natriuretic polypeptide (ANP) on hemodynamics and renal function was evaluated after the reconstructive surgery of the left renal artery in a patient with renovascular hypertension secondary to Takayasu's arteritis. The reconstructive surgery was done using the femoral artery, since we were unable to obtain adequate vein segments to fit the renal artery. The femoral artery was reconstructed by her saphenous vein segments. After 30 min of the aortorenal bypass operation, alpha-human ANP (alpha-hANP) was infused intravenously for 10 min at a rate of 0.1 microgram/kg/min. Although total peripheral resistance was decreased by alpha-hANP infusion, blood pressure was not changed because of the increased cardiac output. Glomerular filtration rate was increased markedly with concomitant increase in urine volume and urinary excretions of sodium, potassium and phosphate. Fractional excretions of water and sodium were not changed, but fractional excretion of phosphate and potassium clearance were increased. Thus, the infusion of alpha-hANP markedly improved the renal function of the ischemic kidney by the reconstructive surgery of the renal artery, suggesting that alpha-hANP seems clinically applicable as a protective agent in renal ischemia at renovascular surgery as well as the renal transplantation.
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PMID:Atrial natriuretic polypeptide (ANP) as protective agent of renal ischemia. 253 78

Ischemia results in the marked reduction of renal proximal tubule function which is manifested by decreased Na+ and H2O reabsorption. In the present studies the possibility that altered Na+ and H2O reabsorption were due to ischemia-induced loss of surface membrane polarity was investigated. Following 15 min of renal ischemia and 2 hr of reperfusion, proximal tubule cellular ultrastructure was normal. However, abnormal redistribution of NaK-ATPase to the apical membrane domain was observed and large alterations in apical membrane lipid composition consistent with loss of surface membrane polarity were noted. These changes were associated with large decreases in Na+ (37.4 vs. 23.0%, P less than 0.01) and H2O (48.6 vs. 36.9%, P less than 0.01) reabsorption at a time when cellular morphology, apical Na+ permeability, Na+-coupled cotransport, intracellular pH and single nephron filtration rates were normal. We propose that the abnormal redistribution of NaK-ATPase to the apical membrane domain is in part responsible for reduced Na+ and H2O reabsorption following ischemic injury.
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PMID:Loss of epithelial polarity: a novel hypothesis for reduced proximal tubule Na+ transport following ischemic injury. 254 Dec 48

The renovascular hypertension in the Wistar rats was induced by clipping both renal arteries. Within 3-4 weeks arterial pressure (AP) increased to maximal values. According to AP, the rats were divided into two groups: with AP less than or equal to 170 mm Hg and greater than 170 mm Hg. In 5-6 or 10-11 weeks the animals were decapitated and the Na,K-ATPase activities in the wholesome erythrocytes, their ghosts, and the cortex and medulla of kidneys were studied. Changes of the enzyme activity were only found in the medulla. A decreased enzyme activity (-20%) was revealed in the rats with AP less than or equal to 170 mm Hg within 5-6 weeks after renal ischemia, the activity increasing again in 10-11 weeks after the operation. The decreasing of Na,K-ATPase activity within 5-6 weeks after renal ischemia could be a mechanism of adaptation of the salt-water balance in animals.
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PMID:[Effect of bilateral renal ischemia on the sodium, potassium ATPase activity of the kidneys and erythrocytes in rats]. 254 69

A persisting incidence of acute renal failure has been observed after operative treatment of thoracoabdominal aortic aneurysm, ruptured abdominal aortic aneurysm and renal artery occlusive disease in patients with preoperative impairment of renal function. Because preservation of kidney function can play an important role in the outcome of these patients, the effects of prostaglandin E1 (PGE1) to prevent ischaemic renal failure were studied in an experimental model. Twenty dogs were exposed to 3 h warm ischaemia by clamping of the supra- and infrarenal aorta and both renal arteries. In 10 dogs PGE1 was given intravenously (100 ng/kg/min) for 15 min before clamping. Ten dogs treated with normal saline served as controls. Glomerular filtration rate, renal plasma flow, plasma creatinine, blood urea nitrogen, urine volume, free water clearance and renovascular resistance were calculated before and after renal ischaemia for both groups. The dogs were followed-up for 2 weeks and radionuclide studies with Tc-99m-MAG3, I-131-OIH and In-113m-DTPA were performed on the third postoperative day to calculate global and split renal clearance, tracer extraction fraction and mean transport time. After renal ischemia 9 dogs of the control group and 3 dogs of the PGE1-group developed acute renal failure (P less than 0.05 due to Fisher's exact text). PGE1 infusion significantly attenuated the postischaemic fall in glomerular filtration rate and renal concentrating ability as well as the postischaemic increase of plasma creatinine and blood urea nitrogen induced by 3 h warm renal ischaemia (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Winner of the ESVS Prize 1988. Effects of prostaglandin E1 (PGE1) on experimental renal ischaemia. 265 70

In a 22 years old woman with recent hypertension, a timed intravenous pyelogram revealed an asymptomatic obstructive ureteropelvic junction. Preoperative renal vein catheterization demonstrated excessive renin release from the diseased kidney and low release from the other one, suggesting that corrective ureteral surgery should return blood pressure to normal levels. Moderately impaired glomerular filtration rate improved after surgery as a consequence of suppressed hydronephrosis and bilateral renal ischemia. Thus we conclude that in young people, asymptomatic unilateral hydronephrosis can lead to hypertension and renal failure like renal artery stenosis. In the other cases of urinary flow obstruction, secondary hypertension remains to be explained by both inappropriate production of renin and water chronic retention.
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PMID:[Arterial hypertension with renin hypersecretion secondary to pyelo-ureteral syndrome. Cure after corrective surgery]. 269 10

To investigate the ability of MRI to detect alterations due to renal ischemia, a rabbit renal artery stenosis (RAS) model was developed. Seven rabbits had RAS induced by surgically encircling the artery with a polyethylene band which had a lumen of 1 mm, 1 to 2 weeks prior to imaging. The stenosis was confirmed by angiography, and the rabbits were then imaged in a 1.4 T research MRI unit. T1 was calculated using four inversion recovery sequences with different inversion times. Renal blood flow, using 113Sn-microspheres, and regional water content by drying were then measured. The average T1 of the inner medulla was shorter for the ischemia (1574 msec) than for the contralateral kidney (1849 msec), while no change ws noted in the cortex. Ischemic kidneys had less distinct outer medullary zones on IR images with TI = 600 msec than did contralateral or control kidneys. Blood flow to both the cortex and medulla were markedly reduced in ischemic kidneys compared with contralateral kidneys (119.5 vs. 391 ml/min/100 gm for cortex and 19.8 vs. 50.8 ml/min/100 gm for medulla). Renal water and blood content were less affected. Our rabbit model of renal artery stenosis with MRI, radionuclide, and angiographic correlation has the potential to increase our understanding of MR imaging of the rabbit kidney.
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PMID:Induced renal artery stenosis in rabbits: magnetic resonance imaging, angiography, and radionuclide determination of blood volume and blood flow. 337 82

Many models have been developed to study renal function following injury. Two types of studies have evolved: acute--to define the acute renal injury and chronic--to determine the pattern of recovery. Current models allow either study alone to be performed, but they lack the flexibility to combine the studies. In this study of renal ischemia, a model was designed which solved this problem. The authors constructed a model for performing a unilateral nephrectomy and episiotomy on female dogs. Catheters were placed in the renal vein, vena cava, and aorta, and a renal artery flow cuff was applied. The catheters and wires were buried in a subcutaneous pocket and were exteriorized after a recovery of several weeks. The episiotomy allowed easy intermittent Foley catheterization. With the animals awake and in a harness, parameters of renal function were measured: renal extraction, filtration fraction, fractional excretion, osmolar clearance, and free water clearance. Glomerular filtration rate and renal plasma flow were calculated by inulin and paramino hippurate clearances. The animals were studied in diuretic and antidiuretic states. In addition, renal artery flow was determined by the Doppler flow cuff. All parameters were determined every half hour in the acute setting, then every day in the chronic setting. The model was easily reproducible and functioned well in the authors' renal ischemia studies. Initial experiments with 1 hour of warm ischemia produced a greater than 50 per cent reduction in GFR acutely. Chronic studies showed a GFR with a return toward normal. All model construction purposes and plans were met.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A new model to study acute and chronic renal failure. 378 43

A computerized model of creatinine kinetics was developed to predict the relationship between creatinine clearance [G(t)] and plasma creatinine concentration [C(t)] in patients with postischemic acute renal failure (ARF). A comparison of predicted to measured values in 35 episodes of ARF in 27 patients revealed three patterns of declining G(t) following an ischemic insult. Pattern A, characterized by an abrupt step decrement in G(t) following an isolated renal ischemic episode lasting minutes or hours, was observed in nine patients. It was followed invariably by an immediate ramp increment in G(t), despite which C(t) continued to increase for several days. Urinary indices during the period of increasing azotemia were consistent with the resolving stage of ARF. Patterns B (N = 15) and C (N = 11) were associated with persistent renal ischemia of long (days to weeks) duration and were respectively characterized by prolonged ramp or exponential decrements in G(t). A concurrent increase in C(t) was associated with urinary indices typical of the maintenance or sustained stage of ARF. Recovery of G(t) was observed in only two-thirds of patterns B and C cases and took the form of a ramp or exponential increment. Because G(t) and total body water were changing rapidly in ARF, changes in measured plasma creatinine levels alone failed to identify these patterns of deteriorating or improving renal function. However, when the computerized model was used in conjunction with daily measured values of C(t) and body weight and occasional estimates of G(t), the course and prognosis of ARF in individual patients were illuminated.
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PMID:Course of acute renal failure studied by a model of creatinine kinetics. 402 21

In 12 dogs anesthetized with chloralose, angiotensin (angiotensin II amide) given intravenously increased the glomerular filtration rate (GFR) of an ischemic kidney while simultaneously having little effect on the GFR of the contralateral kidney. In the ischemic kidney, in 14 of 30 observations, increments of GFR greater than 100% of mean control GFR (9 ml/min) occurred in response to angiotensin. The magnitude of the increase in GFR produced by angiotensin was independent of dose (range 0.005-0.050 mug/kg per min), the degree of accompanying pressor response, and alterations in renal blood flow (RBF) (electromagnetic flow-meter). In the ischemic kidney, increments of GFR could be produced by sub-pressor doses of angiotensin. Dissociations between increments of GFR and sodium excretion occurred. Equivalent increments of GFR in the ischemic kidney in dogs receiving either 5% glucose in water or 10% mannitol in 0.3% saline were associated with natriuresis only in the latter group: a) as an initial response of the contralateral kidney to renal arterial constriction (RAC) in spite of a concomitant reduction in RBF and an unchanged GFR; b) in the ischemic kidney on giving angiotensin. The natriuresis produced by angiotensin was independent of the magnitude of elevations in blood pressure, altered filtration fraction, and was associated with a further reduction in RBF. After release of RAC in the dogs receiving mannitol, an antinatriuresis was again observed in response to angiotensin. The presence of unilateral renal ischemia allowed the demonstration of a differential action of angiotensin on the GFR of an ischemic and nonischemic kidney. The natriuresis in response to angiotensin requires, in addition to mannitol, the participation of undefined factors invoked by unilateral renal ischemia.
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PMID:Some determinants of the effects of VAL-5-angiotensin II amide on glomerular filtration rate and sodium excretion in dogs. 430 89


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