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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mannitol may be useful clinically both as a diuretic and as an obligate extracellular solute. As a diuretic it can be used to treat patients with intractable edema states, to increase urine flow and flush out debris from the renal tubules in patients with acute tubular necrosis, and to increase toxin excretion in patients with barbiturate, salicylate or bromide intoxication. As an obligate extracellular solute it may be useful to ameliorate symptoms of the dialysis disequilibrium syndrome, to decrease cerebral edema following trauma or cerebrovascular accident, and to prevent cell swelling related to renal ischemia following cross-clamping of the aorta. Largely unexplored uses for mannitol include its use as an osmotic agent in place of dextrose in peritoneal dialysis solutions, its use to maintain urine output in patients newly begun on hemodialysis, and its use to limit infarct size following acute myocardial infarction.
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PMID:Mannitol. 38 67

The use of cardiopulmonary bypass, deep hypothermia and circulatory arrest has decreased the risks of hemorrhage, tumor embolization, incomplete thrombus resection, and warm hepatic and renal ischemia associated with resection of renal cell carcinoma extending into the inferior vena cava above the hepatic veins. Patients about to undergo this operation frequently have significant coronary artery and carotid artery disease, and are at risk for perioperative myocardial infarction and stroke. Preoperative evaluation of the coronary artery and carotid artery circulation by coronary angiography, duplex carotid artery scan and digital subtraction carotid angiography is recommended. Depending upon the severity and location of the cardiovascular disease a sequential or simultaneous operation may be performed. This surgical approach can be used in selected patients to facilitate complete tumor thrombectomy with a low operative risk.
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PMID:Cardiovascular evaluation before circulatory arrest for removal of vena caval extension of renal carcinoma. 272 26

To elucidate the significance of hypertension associated with cerebrovascular lesions (CVL), renal perfusion pressure (RPP) was controlled by aortic clips of two different sizes in stroke-prone spontaneously hypertensive rats kept under normal or salt-loaded conditions. Tail and femoral arterial pressures (RPPs) in the mildly and severely clamped animals were reduced in proportion to the severity of the clamping. In contrast, carotid pressures in both clamped groups were significantly higher than that in the controls. Proteinuria and hyperreninemia accompanied by arteriolar changes in the renal cortex were observed in the controls prior to the onset of CVL. The renal changes were inhibited by both types of clamping. The onset of CVL was delayed by the mild clamping in salt-loaded animals, but accelerated by the severe clamping in both the normal and salt-loaded animals. Renal cortical blood flow was decreased only by the severe clamping. The results suggest that reduction in RPP and/or renal ischemia, which seems to be due to the hypertensive arteriolar changes in the renal cortex, may be related to the pathogenesis of CVL in the stroke-prone rats with or without hyperreninemia.
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PMID:Implication of renal perfusion pressure in stroke of spontaneously hypertensive rats. 736 76

The major message from this discussion is that the end points from hypertensive disease (stroke, CHD, and hypertensive emergencies) are now preventable. Cardiac failure and ESRD, however, two exceedingly common end points from long-standing hypertension, remain as major disabilities and causes of death. The former is the most common cause of hospitalization in industrialized societies; hypertension and diabetes mellitus are the most common causes of the latter. The mechanisms of risk of these target organ diseases is not LVH per se, or the elevated arterial pressure alone in the kidney, but the coronary and renal ischemia, organ fibrosis, and, perhaps, apoptosis. Present day therapy now can effectively reverse these costly (economically and by human suffering) complications. Recent experimental studies suggest that, when used early enough, these newer pharmacologic agents may even prevent their occurrences and consequences. The very practical lesson from these experiences is that early detection and treatment of hypertension, effective control of arterial pressure, and the suppression of the underlying disease mechanisms markedly reduce the now increasing prevalence of both cardiac and renal failure.
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PMID:Target organ involvement in hypertension: a realistic promise of prevention and reversal. 1487 Oct 60

Anemia is found in about one-third of all cases of congestive heart failure (CHF). The most likely common cause is chronic kidney insufficiency (CKI), which is present in about half of all CHF cases. The CKI is likely to be due to the renal vasoconstriction that often accompanies CHF and can cause long-standing renal ischemia. This reduces the amount of erythropoietin (EPO) produced in the kidney and leads to anemia. However, anemia can occur in CHF without CKI and is likely to be due to excessive cytokine production (for example, tumor necrosis factor-alfa (TNF-alfa) and interleukin-6 (IL-6)), which is common in CHF and can cause reduced EPO secretion, interference with EPO activity in the bone marrow and reduced iron supply to the bone marrow. The anemia itself can worsen cardiac function, both because it causes cardiac stress through tachycardia and increased stroke volume, and because it can cause a reduced renal blood flow and fluid retention, adding further stress to the heart. Long-standing anemia of any cause can cause left ventricular hypertrophy (LVH), which can lead to cardiac cell death through apoptosis and worsen the CHF. Therefore, a vicious circle is set up wherein CHF causes anemia, and the anemia causes more CHF and both damage the kidneys worsening the anemia and the CHF further. We have termed this vicious circle the cardio renal anemia (CRA) syndrome. Patients with CHF who are anemic are often resistant to all CHF medications resulting in being hospitalized repeatedly. Many studies also demonstrate that these patients die more rapidly than their non-anemic counterparts do. In addition, they have a more rapid deterioration in their renal function and can end up on dialysis. There is now evidence from both uncontrolled and controlled studies that early correction of the CHF anemia with subcutaneous EPO and intravenous (i.v.) iron improves shortness of breath and fatigue, cardiac function, renal function and exercise capability, dramatically reducing the need for hospitalization. For these reasons, it is not surprising that quality of life has also been shown to improve. As both CHF and end-stage renal disease (ESRD) are rapidly increasing, the possibility that these twin conditions can be improved by the adequate treatment of anemia offers new hope for slowing the progression of both conditions.
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PMID:The role of anemia in the progression of congestive heart failure. Is there a place for erythropoietin and intravenous iron? 1559 47

Acute Renal Failure (ARF) is the most costly kidney disease in hospitalized patients and remains as a serious problem in clinical medicine. The mortality rate among ARF patients remains around 50% and no pharmaceutical agents are currently available to improve its clinical outcome. Although several successful therapeutic approaches have been developed in animal models of the disease, translation of the results to clinical ARF remains elusive. Understanding the cellular and molecular mechanisms of vascular and tubular dysfunction in ARF is important for developing acceptable therapeutic interventions. Following an ischemic episode, cells of the affected nephron undergo necrotic and/or apoptotic cell death. Necrotic cell death is widely considered to be a futile process that cannot be modulated by pharmacological means as opposed to apoptosis. However, recent reports from various laboratories including ours indicate that inhibition or absence of poly(ADP)-ribose polymerase (PARP), one of the molecules involved in cell death, provides remarkable protection in disease models such as stroke, myocardial infarction and renal ischemia which are characterized predominantly by necrotic type of cell death. Overactivation of PARP in conditions such as ischemic renal injury leads to cellular depletion of its substrate NAD+ and consequently ATP. The severely compromised cellular energetic state induces acute cell injury and diminishes renal functions. PARP activation also enhances the expression of proinflammatory agents and adhesion molecules in ischemic kidneys. Pharmacological inhibition and gene ablation of PARP-1 decreased energy depletion, inflammatory response and improved renal functions in the setting renal ischemia/reperfusion injury. The biochemical pathways and the cellular and molecular mechanisms mediated by PARP-1 activation in eliciting the energy depletion and inflammatory responses in ischemic kidney are not fully elucidated. Dissecting the molecular mechanisms by which PARP activation contributes to oxidant-induced cell death will provide new strategies to interfere in those pathways to modulate cell death in renal ischemia. The current review evaluates the experimental evidences in animal and cell culture models implicating PARP as a pathophysiological modulator of acute renal failure with particular emphasis on ischemic renal injury.
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PMID:Poly(ADP-ribose) polymerase-mediated cell injury in acute renal failure. 1591 33

The processes involved in the renal damage resulting from ischemia-reperfusion injury are poorly understood. This study examined the contribution of prostaglandins and nitric oxide (NO) in the vascular responses to ischemia-reperfusion injury in the kidneys of normotensive and hypertensive rats. Groups of Wistar and stroke-prone spontaneously hypertensive rats (SHRSP) were dosed with polyethylene glycol vehicle, aspirin (53.5 mg.kg(-1).day(-1)), NO-aspirin (100 mg.kg(-1).day(-1)), or celecoxib (10 mg.kg(-1).day(-1)) for 7 days. On day 7, rats were anesthetized with chloralose/urethane and the left kidney was exposed to a 30-min period of ischemia followed by 90-min reperfusion. Renal cortical and medullary perfusions were monitored throughout using laser-Doppler flowmetry. In the vehicle- and celecoxib-treated Wistar rats, cortical and medullary postischemic perfusion was reduced to 66 and 62% and 53 and 62%, respectively (all P < 0.05), of baseline. The ischemia-induced reductions in cortical and medullary flux were ameliorated in the aspirin and NO-aspirin groups where flux fell to 96 and 78% and 105 and 83%, respectively (P < 0.05). There was a fall in cortical and medullary flux in the postischemic period in the vehicle-treated SHRSP to 82 and 77% (P < 0.05). These findings show that nonselective cyclooxygenase (COX) inhibition, and to an even greater extent NO donation, provided protection to the renal vasculature from ischemic injury in the Wistar rat but not in the SHRSP. This would suggest that prostaglandins are less important in the development of renal ischemia-reperfusion injury during hypertension and both COX isoforms must be inhibited to offset the decrease in renal hemodynamics.
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PMID:Effect of COX inhibitors and NO on renal hemodynamics following ischemia-reperfusion injury in normotensive and hypertensive rats. 1595 74

Apoptosis has a role in many medical disorders, therefore assessment of apoptosis in vivo can be highly useful for diagnosis, follow-up and evaluation of treatment efficacy. ApoSense is a novel technology, comprising low molecular-weight probes, specifically designed for imaging of cell death in vivo. In the current study we present targeting and imaging of cell death both in vitro and in vivo, utilizing NST-732, a member of the ApoSense family, comprising a fluorophore and a fluorine atom, for both fluorescent and future positron emission tomography (PET) studies using an (18)F label, respectively. In vitro, NST-732 manifested selective and rapid accumulation within various cell types undergoing apoptosis. Its uptake was blocked by caspase inhibition, and occurred from the early stages of the apoptotic process, in parallel to binding of Annexin-V, caspase activation and alterations in mitochondrial membrane potential. In vivo, NST-732 manifested selective uptake into cells undergoing cell-death in several clinically-relevant models in rodents: (i) Cell-death induced in lymphoma by irradiation; (ii) Renal ischemia/reperfusion; (iii) Cerebral stroke. Uptake of NST-732 was well-correlated with histopathological assessment of cell-death. NST-732 therefore represents a novel class of small-molecule detectors of apoptosis, with potential useful applications in imaging of the cell death process both in vitro and in vivo.
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PMID:Molecular imaging of cell death in vivo by a novel small molecule probe. 1705 35

Ischemia has elicited a great deal of interest among the scientific community due to its role in life-threatening pathologies such as cancer, stroke, acute renal failure, and myocardial infarction. Oxygen deprivation (hypoxia) associated with ischemia has recently become a subject of intense scrutiny. New investigators may find it challenging to induce hypoxic injury in vitro. Researchers may not always be aware of the experimental barriers that contribute to this phenomenon. Furthermore, ischemia is associated with other major insults, such as excess carbon dioxide (hypercapnia), nutrient deprivation, and accumulation of cellular wastes. Ideally, these conditions should also be incorporated into in vitro models. Therefore, the motivation behind this review is to: i. delineate major in vivo ischemic insults; ii. identify and explain critical in vitro parameters that need to be considered when simulating ischemic pathologies; iii. provide recommendations to improve experiments; and as a result, iv. enhance the validity of in vitro results for understanding clinical ischemic pathologies. Undoubtedly, it is not possible to completely replicate the in vivo environment in an ex vivo model system. In fact, the primary goal of many in vitro studies is to elucidate the role of specific stimuli during in vivo pathological events. This review will present methodologies that may be implemented to improve the applicability of in vitro models for understanding the complex pathological mechanisms of ischemia. Finally, although these topics will be discussed within the context of renal ischemia, many are pertinent for cellular models of other organ systems and pathologies.
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PMID:Experimental strategies to improve in vitro models of renal ischemia. 1749 Jun 40

1. Acute renal failure develops as a result of periods of renal ischaemia during cardiovascular surgery or hypovolaemic shock. The present study investigated the importance of endogenous prostaglandin production and nitric oxide (NO) in the renal haemodynamic and excretory responses to ischaemia-reperfusion both normally and in the hypertensive state by chronic administration of cyclo-oxygenase (COX) inhibitors. 2. Male Wistar and stroke-prone spontaneously hypertensive rats (SHRSP) were subjected to 30 min renal ischaemia and 2 h reperfusion following 7 day treatment with vehicle, aspirin, NO-aspirin or celecoxib. 3. Renal blood flow was higher in the SHRSP treatment groups. Renal ischaemia increased blood pressure in all Wistar groups except that given aspirin, had no effect in the SHRSP and did not change renal blood flow in any group. Glomerular filtration rate was reduced throughout the reperfusion period in both rat strains. The postischaemic diuresis in the Wistar was enhanced by COX-2 inhibition, but not by aspirin or NO-aspirin. Urine flow increased in SHRSP during the postischaemic period, which was blunted by aspirin and NO-aspirin, but not by celecoxib. There was a postischaemic increase in fractional sodium excretion, the magnitude of which was unaltered by any drug in the Wistar rats, but was blunted by aspirin, NO-aspirin and celecoxib in SHRSP. 4. These results suggest that products of COX activity contribute to the renal responses to ischaemia-reperfusion injury, but in different ways, in SHRSP, which may reflect variations in renal prostaglandin and NO production in the hypertensive state.
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PMID:Renal functional responses to ischaemia-reperfusion injury in normotensive and hypertensive rats following non-selective and selective cyclo-oxygenase inhibition with nitric oxide donation. 1804 21


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