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)

Studies were performed to determine whether renal glutathione (GSH) is an important free-radical scavenger following ischemia and reperfusion, whether alterations in renal transport work affect renal GSH levels, and whether a decrease in renal work decreases susceptibility to postischemic renal injury via the first two effects. Following administration of either intravenous GSH to increase renal GSH or intraperitoneal diethylmaleate to decrease renal GSH, Sprague-Dawley rats underwent 60 minutes of renal ischemia. In animals with high renal GSH following GSH infusion, GFR 24 hours after ischemia was 0.43 +/- 0.08 ml/min compared to 0.15 +/- 0.02 ml/min in saline-infused control animals (P less than 0.01). When renal GSH was decreased by the administration of diethylmaleate postischemic renal dysfunction was accentuated. Twenty-four hours after ischemia GFR was 0.05 +/- 0.02 ml/min in diethylmaleate-treated animals and 0.28 +/- 0.06 ml/min in control animals (P less than 0.005). To test whether a decrease in renal transport work alters renal GSH the filtered load of sodium was reduced by producing unilateral renal artery stenosis. Alternatively, renal work was lessened when sodium reabsorption was interfered with by the infusion of a combination of natriuretic agents. Renal artery stenosis produced a 37% decrease in GFR. Renal GSH was 0.435 +/- 0.089 nmol/mg protein in intact kidneys and 0.804 +/- 0.239 nmol/mg protein in stenotic kidneys (P less than 0.05). The infusion of natriuretic agents produced no change in GFR or renal plasma flow but resulted in a striking elevation in renal GSH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal work, glutathione and susceptibility to free radical-mediated postischemic injury. 338 36

The potential of CT scanning to explore total and regional renal blood flow was evaluated in a dog model with unilateral renal artery stenosis (n = 7, reduction of renal blood flow: 32-75% of base line flow). Attenuation versus time curves were generated for the renal cortex and medulla, as well as for the aorta and renal vein. A fast CT scanner was used which allowed for up to 24 scans/minute at the same level (slice thickness: 10 mm). A total of 10 ml contrast medium was injected into a peripheral vein for each scan series taken. During baseline conditions, the curve of the renal cortex and medulla demonstrated 2 peaks. The first peak was mainly related to early vascular enhancement, whereas the second peak corresponded mainly to the appearance of contrast medium in the distal convolutes and collecting ducts. Ischemia of the kidney resulted in a reduction of the first peak and a flattening of the leading edge slope. Transport of contrast medium through the extravascular compartments of the kidney was delayed during ischemia. Relative renal blood flow was obtained from the CT data by dividing peak enhancement by rise-time as assessed from the cortical curve. All measurements were related to baseline flow and validated by flow measurements using radioactive labeled microspheres (n = 5). Correlation was found to be r = 0.97.
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PMID:Attenuation changes of the normal and ischemic canine kidney. Dynamic CT scanning after intravenous contrast medium bolus. 401 22

Percutaneous transluminal angioplasty (PTA) was attempted on 16 nonatherosclerotic lesions in 14 patients. Dilatation was initially successful in 4/4 cases with renal artery stenosis due to fibromuscular dysplasia (three) and Takayasu arteritis (one); all patients became normotensive and remain normotensive on no antihypertensive medications, at up to 12 months follow-up. PTA was technically successful in 4/5 transplant renal artery stenosis; these four patients remain normotensive or almost normotensive on no or markedly reduced antihypertensive medications, at up to 14 months followup. Initial success was obtained in 3/3 lesions involving vascular grafts; in one, the patient became and remained asymptomatic for the remaining 5 months he lived; in another, occlusion of the dilated segment and the graft occurred 8 months after PTA; and in the third, symptoms and signs of the limb ischemia returned within 24 hr of PTA. PTA was initially successful in a patient with recurrent celiac artery stenosis after surgery for median arcuate ligament syndrome; she has remained free of symptoms for 18 months. In a patient with three radiation-induced stenoses, PTA was initially successful; this patient is asymptomatic at 20 months follow-up. The medial type of fibromuscular dysplasia dilates most easily, suggesting a concentric stretching and some shearing of the fibrous tissue, which then heals in its dilated state. Intimal fibroplasia may be eccentric, and concentric stretching during dilatation may not be possible, leading to less satisfactory results. Radiation-induced stenosis involves periarterial fibrosis and arterial wall thickening, and the results in PTA of many of these lesions may be less satisfactory than reported here. The responsiveness of graft stenoses will vary with the cause; anastomotic stenoses will probably dilate easily, for they involve either concentric intimal proliferation, or a small degree of periarterial fibrosis; graft stenoses surrounded by dense fibrous tissue may respond initially to PTA, but the long-term results will probably be poor due to recurrent graft constriction.
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PMID:Percutaneous transluminal angioplasty of nonatherosclerotic lesions. 610 4

Collateral lumbar arterial blood supply to an autotransplanted kidney was angiographically documented in a patient with bilateral Wilms' tumor and postoperative transplant renal artery stenosis. During autotransplantation, most collateral pathways are interrupted. The development of a collateral circulation after autotransplantation may be postulated to begin with a vascular response to postoperative inflammation and adhesions. The small anastomotic pathways so formed may then dilate in response to ischemia resulting from renal artery stenosis.
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PMID:Collateral blood supply to an autotransplanted kidney. 626 87

Vasculopathy in the syndrome of Von Recklinghausen's neurofibromatosis is a well known but clinically underestimated phenomenon. Its manifestations have included renovascular hypertension, occlusive cerebrovascular disease and visceral ischemia. The progressive arterial disease may involve small vessels on a regular basis and large vessels in a variety of angiographic patterns. A young neurofibromatosis patient is described with an aneurysm of the superior mesenteric artery complicating renovascular hypertension associated with aortic coarctation and renal artery stenosis. This unique angiographic demonstration illustrates the therapeutic dilemmas posed by the vascular disease associated with Von Recklinghausen's neurofibromatosis.
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PMID:Von Recklinghausen's vasculopathy. 642 59

In a 71-year-old female with severe hypertension, bilateral renal artery stenosis and renal adenocarcinoma, a renal vein renin study revealed suppressed renin secretion from the kidney with carcinoma and contralateral ischemia. The hypertension was not cured by surgical removal of the kidney with carcinoma. Hypertension is frequently noted in patients with renal adenocarcinoma (28% of 603 patients reported in the literature). This type of hypertension is frequently improved after removal of the tumor (83% of 36 surgically treated patients). In certain patients the pathogenesis of hypertension associated with renal adenocarcinoma may be related to renin secretion from the tumor or to renin activation due to regional ischemia caused by vascular compression. In other patients the renin-angiotensin system does not appear to play a pathogenic role in the development of hypertension associated with renal adenocarcinoma.
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PMID:[Arterial hypertension: adenocarcinoma of the kidney or bilateral renal artery stenosis$]. 672 21

Hypoplasia of the abdominal aorta is a rare cause of renovascular hypertension. Arteriographic studies of the renal vasculature are presented from an infant with hypoplasia of the abdominal aorta and segmental renal artery stenosis. The renovascular hypertension was cured by partial nephrectomy. There was no difference in the parenchymal histology in the tissue from the congenitally ischemic lower pole of the kidney and the vascularized upper pole. In this unique case with decreased renal blood flow during fetal development there was no evidence that parenchymal ischemia can cause renal parenchymal hypoplasia.
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PMID:Renovascular hypertension in an infant with segmental renal artery stenosis and hypoplasia of the abdominal aorta. 686 92

We report two cases of severe hypertension and unilateral renal dysplasia. No renal artery stenosis and no other urogenital malformations were found. In both cases we found substantially enhanced secretion of renin from the dysplastic kidney. After nephrectomy both patients obtained a distinctive and permanent reduction or normalization of blood pressure. In the two cases reported, regional renin release induced by ischemia is a very likely etiological factor.
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PMID:The etiology of hypertension in nonrenovascular unilateral renal disease--two cases of renin induced hypertension in congenital renal dysplasia. 759 51

A 4-year-old boy had severe hypertension, cardiac failure, and signs of neurofibromatosis. Arteriography disclosed renal artery stenosis in both kidneys with signs of ischemia, particularly in the right kidney. Because of insufficient response to antihypertensive therapy, a right-sided nephrectomy was performed. Histological examination of this kidney showed segmental stenosis in all branches of the renal artery. The vascular lesions were characterized by an intimal proliferation of spindle cells in a mucoid matrix with destruction of the internal elastic membrane frequently accompanied by loss or attenuation of the media and fibrosis of the adventitia. Occasionally, a nodular arrangement of the spindle cells at the interface between intima and media was observed. Immunohistochemical studies demonstrate a smooth-muscle cell origin for these cells.
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PMID:A 4-year-old boy with neurofibromatosis and severe renovascular hypertension due to renal arterial dysplasia. 817 25

The clearance of [131I]orthoiodohippurate and 99mTc-mercaptoacetyltriglycine provide a measure of effective renal plasma flow, yet these clearances are proportional to renal plasma flow only if the extraction fraction remains constant. To determine the effect of unilateral renal artery stenosis, captopril, renal ischemia, and partial renal vein occlusion on renal blood flow and the extraction fraction of [131I]orthoiodohippurate, 99mTc-mercaptoacetyltriglycine, and [125I]iothalamate, we conducted a series of constant infusion studies in Sprague-Dawley rats. Renal artery flow reduction of approximately 70% decreased the extraction fraction of all three agents (P < or = .05). Captopril had no effect on extraction fraction in controls, but it produced a further decrease in extraction fraction of 99mTc-mercaptoacetyltriglycine and [131I]orthoiodohippurate in rats with renal artery stenosis (P < or = .05). Ischemia resulted in a 16% decrease in flow (P < .01) but a much larger (47% to 65%) decrease in extraction fraction of all three agents (P < .002). Partial renal vein occlusion also decreased the extraction fraction of all three agents (P < or = .05). The changes in extraction fraction imply that the clearances of [131I]orthoiodohippurate and 99mTc-mercaptoacetyltriglycine in disease states may not be proportional to renal plasma flow. Furthermore, in rats with renal artery stenosis it appears that renal blood flow must fall below a critical threshold of approximately 58% before extraction fraction decreases; as renal blood flow is further reduced below this threshold, there is a corresponding reduction in extraction fraction (P < .01).
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PMID:Renal artery stenosis and ischemia. Effect on renal blood flow and extraction fraction. 828 36


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