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)

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

Rats were anesthetized and their lift kidneys were made ischemic for 1 h by clamping of the aorta just above the left renal artery. Mannitol (2.5 g/kg), Dextran 70 (0.6 g/kg), methylprednisolone (50 and 100 mg/kg), and allopurinol (100 mg/kg body weight) were administered before, during, or after the ischemia period in order to test the effect of each of these drugs upon this model of renal injury. At 24 h after the release of the aortic clamp the left kidneys of the drug treated animals wwere perfusion fixed and processed for light and electron microscopy. Dextran administration to animals with ischemic kidneys gave rise to a pronounced vacuolization ("osmotic nephrosis"), in the entire proximal tubule and especially in the pars recta. This was in contrast to dextran administration to rats with nonischemic kidenys, which showed no or very mild "osmotic nephrosis." This demonstrates that ischemia makes rat kidneys more susceptible to the development of "osmotic nephrosis." In controls (no drug treatment) one hour of renal ischemia gave partial necrosis of pars recta of the proximal tubule, while the pars convoluta tubule survived. Mannitol treatment significantly reduced the amount of necrosis of the pars recta, whereas dextran, methylprednisolone, and allopurinol had no or a negative effect on the survival of the cells of the pars recta segment. It is suggested that mannitol protects against the development of necrosis by increasing medullary blood flow in combination with a counteractive influence on the cellular swelling, which is known to occur in ischemia.
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PMID:Effect of mannitol, dextran (macrodex), allopurinol, and methylprednisolone on the morphology of the proximal tubule of the rat kidney made ischemic in vivo. 40 53

Tandem Scanning Confocal Microscopy (TSCM) allows one to section optically into and record real-time images of living organs and tissues in a noninvasive fashion. In this paper, we will present some initial TSCM observations of subcapsular nephrons in the living, intact kidneys of Munich-Wistar rats and evaluate the nephron's responses to temporary ischemia and to intravenous infusion of mannitol. The rats were anesthetized with Inactin and a laparotomy performed to expose the kidneys. Using a TSCM equipped with a 20 x water-immersion objective, we optically sectioned through the intact kidney capsule and recorded real-time images of living subcapsular glomeruli and uriniferous tubules. The proximal tubule brush border was highly reflective and allowed us to distinguish between the first and second segments of the proximal tubules as well as the distal tubules. Cellular elements of the blood could be seen passing rapidly through peritubular capillaries and individual glomerular capillary loops. With fluorescent filters in place, intravenously injected carboxyfluorescein was seen to pass through the glomerular capillary loops and then progressively through the different segments of the uriniferous tubules. Ligation of the renal artery resulted in rapid swelling of proximal tubule cells into the tubular lumens, loss of reflectiveness of the microvillous brush borders, and closure of the peritubular capillary spaces. Upon release of the ligature, the proximal tubule lumens again became patent, often opening up abruptly and in a zipper-like fashion down the length of the tubules. Increasing the glomerular filtration rate by intravenous infusion of mannitol resulted in increases in tubular luminal and perimeter dimensions. Mannitol also acted as an effective impermeant osmotic agent and prevented most of the cellular swelling which was otherwise seen in response to renal ischemia.
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PMID:Tandem scanning confocal microscopy (TSCM) of normal and ischemic living kidneys. 190 77

Oliguria has been considered a cardinal feature of acute renal failure. Most studies indicate that non oliguric forms of acute renal failure are associated with less morbidity and mortality than oliguric forms. Mannitol, loop diuretics and dopamine have been used to prevent and treat renal ischemia. Although the final fate of patients with oliguric acute renal failure is more influenced by the primary disease than by anuria per se the possibility of reversing anuria seems to represent a better prognostic factor in the outcome of these patients.
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PMID:Acute renal failure: prevention and treatment. 211 13

Experiments were performed on rats to examine the cause of the vascular congestion that accompanies renal ischemia, and the potential role of cell swelling in its generation. Renal function and gross morphology were examined after reflow, whereas tissue morphometry was performed both before and after reflow in kidneys. Small doses of mannitol applied into the renal artery just before ischemia greatly reduced the incidence of vascular congestion and the depression of renal function. During ischemia the outwardly directed swelling of the proximal tubule depleted the interstitial and vascular space of the cortex and outer medullary outer stripe and the inwardly directed swelling of the thick ascending limb occluded the lumen. Mannitol reduced cell swelling, lessened the depletion of the interstitial and vascular space and eliminated the occlusion of the thick ascending limb. It is proposed that the loss of interstitial and vascular fluid during ischemia is the cause of the vascular congestion, which, in turn, is responsible for the poor perfusion and impaired renal function seen after ischemia.
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PMID:Vascular congestion in ischemic renal failure: the role of cell swelling. 249 26

Tubular transport abnormalities have recently been characterized in a rabbit model of ischemic acute renal failure (ARF). These studies demonstrated severe observable morphologic and functional changes in the proximal nephron together with functional changes in the distal nephron. Tubular debris was often produced by perfusion of proximal nephron segments. In the present study, agents used to prevent ARF were tested in this rabbit model of ARF. Rabbits were infused with either 5% body wt 5% manitol or 20 micrograms . kg-1 . min-1 furosemide in 5% body wt normal saline for the 60 min preceding 60 min of total renal ischemia. Mannitol 1) prevented the development of ARF, 2) maintained fluid reabsorption in the proximal convoluted tubule (PCT) (0.59 +/- 0.03 vs. 0.52 +/- 0.1 nl . mm-1 . min-1) and proximal straight tubule (PST) (0.34 +/- 0.05 vs. 0.39 +/- 0.07 nl . mm-1 . min-1), 3) depressed NaCl reabsorption in the cortical thick ascending limb of Henle's loop (TALH), and 4) did not prevent a decrease in ADH-mediated osmotic water flow in the cortical collecting tubule (CCT). Furosemide 1) partially preserved renal function, 2) partially protected the PCT (0.63 +/- 0.05 vs. 0.38 +/- 0.04 nl . mm-1 . min-1) and PST (0.32 +/- 0.04 vs. 0.22 +/- 0.02 nl . mm-1 . min-1), and 3) did not change the transport capacity of the TALH or the ADH response of the CCT. Preservation of proximal nephron integrity was also reflected by the absence of debris formation. There is a direct relation between an agent's ability to protect the functional integrity of the cells of the proximal nephron and its ability to preserve renal function.
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PMID:Prior mannitol and furosemide infusion in a model of ischemic acute renal failure. 679 34

Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can provide non-invasive, cross-sectional, high-resolution images of tissue morphology in situ and in real-time. In the present series of studies, we used a high-speed OCT imaging system equipped with a frequency-swept laser light source (1.3 mum wavelength) to study living kidneys in situ. Adult, male Munich-Wistar rats were anesthetized, a laparotomy was performed and the living kidneys were exposed for in situ observation. We observed the kidneys prior to, during and following exposure to renal ischemia induced by clamping the renal artery. The effects of intravenous mannitol infusion (1.0 ml of 25%) prior to and during renal ischemia were also studied. Finally, living kidneys were flushed with a renal preservation solution, excised and observed while being stored at 0-4 degrees C. Three-dimensional OCT data sets enabled visualization of the morphology of the uriniferous tubules and the renal corpuscles. When renal ischemia was induced, OCT revealed dramatic shrinkage of tubular lumens due to swelling of the lining epithelium. Three-dimensional visualization and volumetric rendering software provided an accurate evaluation of volumetric changes in tubular lumens in response to renal ischemia. Observations of kidneys flushed with a renal preservation solution and stored at 0-4 degrees C also revealed progressive and significant loss of tubular integrity over time. Intravenous infusion of mannitol solution resulted in thinning of the tubular walls and an increase in the tubular lumen diameters. Mannitol infusion also prevented the cell swelling that otherwise resulted in shrinkage of proximal tubule lumens during ischemia. We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the living kidney in a non-invasive fashion. Possible clinical applications are discussed.
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PMID:High-resolution optical coherence tomography imaging of the living kidney. 1826 76

Mannitol for renal protection during partial nephrectomy is common but unsupported by evidence from clinical trials. The impact of mannitol on renal physiology includes both beneficial and harmful effects. Current understanding of renal ischemia reperfusion injury suggests potentially targetable processes that have a lower potential risk.
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PMID:Examining Mannitol Use in Kidney Cancer Surgery: A Cautionary Tale of Extrapolated Surgical Data. 3162 80