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

Using liver allografts with warm or cold ischemia, we evaluated functional and morphological alterations in hepatocytes, sinusoidal endothelial cells and Kupffer cells in a rat transplantation model. All recipients of allografts with either 4 hr of cold or 30 min of warm ischemia lived more than 22 days and were judged viable. On the other hand, all recipients of grafts with 6 hr of cold or 60 min of warm ischemia died within 2 days and were therefore judged to be nonviable. With these viable and nonviable allograft models, hepatocyte function was evaluated by the bile output and serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase and serum lactate dehydrogenase levels; endothelial cell function was judged by the serum hyaluronic acid level, and Kupffer cell function was measured by an intravenous colloidal carbon clearance test. Hepatocyte injury was the prominent feature in warm ischemic grafts, especially in the nonviable ones. On the other hand, serum hyaluronic acid values were significantly higher in the nonviable cold ischemic group, compared with the viable counterpart, suggesting that the functional depression of endothelial cells was predominant in cold, nonviable livers. Histological examinations coincided with the above findings. The phagocytic activity of Kupffer cells was depressed by warm or cold ischemia, whereas the number of Kupffer cells was reduced in the warm ischemia group. We conclude that in liver allografts the main site of injury in warm ischemia is the hepatocytes and suggest that cold ischemia is associated with endothelial cell damage.
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PMID:Ischemic injury in liver transplantation: difference in injury sites between warm and cold ischemia in rats. 163 55

A vast amount of circumstantial evidence implicates oxygen-derived free radicals, especially superoxide and hydroxyl radical (and to lesser extent, hydrogen peroxide), as mediators of inflammation and/or tissue destruction in inflammatory and arthritic disorders. The substrates for radical generation, namely properly stimulated phagocytic cells, transition metal catalysts, and (to a limited extent) ischemia, are all amply present, although there is no particular rheumatic disease in which a consistent abnormality of radical generation has been identified. These radical species can clearly degrade hyaluronic acid, modify collagen and perhaps proteoglycan structure and/or synthesis, alter and interact with immunoglobulins, activate enzymes and inactivate their inhibitors, and possibly participate in chemotaxis. In most situations, however, there is ample scavenging ability to detoxify these radicals before they hit their target, and many rheumatic disease drugs can decrease their production and/or effects. Despite the apparent sufficiency of natural scavengers and the lack of direct evidence that oxygen radicals are pathogenetically important, substantial pharmaceutical effort is still being made to develop free radical scavengers as therapeutic agents. Although individual free radicals die out quickly, rheumatologic interest in them has been sustained for nearly two decades.
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PMID:Oxygen radicals, inflammation, and arthritis: pathophysiological considerations and implications for treatment. 204 55

Bovine testicular hyaluronidase (BTH) reduces experimental myocardial infarct size and ameliorates electrocardiographic signs of ischemia. This study was done to determine if heparin, an in vitro inhibitor of hyaluronidase activity, blocks the action of BTH in the myocardium of dogs after coronary artery occlusion. BTH was administered intravenously as 5,000 NF units/kg at 0.5 and 2.5 hours after coronary occlusion. Heparin was administered intravenously as a 150-unit/kg loading dose, followed by 10 units/kg per hour i.v., beginning 15 minutes before coronary occlusion. The area of myocardial ischemia at risk was assessed by a radiolabeled microsphere technique; the area that developed necrosis was assessed by a histochemical technique. In vivo activity of BTH was assessed by a colorimetric analysis of the BTH substrate, i.e., hyaluronic acid (HA), extracted from myocardial tissue. For biochemical analysis of HA, the heart was divided into anterior myocardium, which included ischemic tissue and posterior nonischemic myocardium. The myocardial HA content of dogs treated with BTH plus heparin (anterior, 3.44 +/- 0.40 micrograms HA/mg protein; posterior, 3.69 +/- 0.33 micrograms HA/mg protein) was not significantly different from control (anterior, 3.61 +/- 0.29 micrograms HA/mg protein; posterior, 3.55 +/- 0.23 micrograms HA/mg protein). In contrast, BTH lowered myocardial HA content (anterior, 2.16 +/- 0.21 micrograms HA/mg protein; posterior, 2.08 +/- 0.14 micrograms HA/mg protein) compared with either BTH plus heparin or control groups in both anterior myocardium (p = 0.006) and posterior myocardium (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heparin inhibits bovine testicular hyaluronidase activity in myocardium of dogs with coronary artery occlusion. 670 49

To verify the role of donor nutritional status on the quality of liver preservation after cold storage, we assessed hepatocyte and liver endothelial cell viabilities and functions in an isolated perfused rat liver model. Livers from fed and fasted Wistar rats were isolated and perfused either immediately after liver harvesting or after a 24-hr cold (4 degrees C) preservation in University of Wisconsin solution. Hyaluronic acid (150 ng/ml) and taurocholate (11.5 micrograms/ml) were infused into the reservoir, and their eliminations were assessed to evaluate liver endothelial cell function and hepatocyte function, respectively. Liver viability was estimated by intrahepatic resistance, oxygen consumption, bile secretion, and lactate dehydrogenase release. In addition, cell viabilities were evaluated by trypan blue staining. In fed-rat livers, glycogen content did not differ before or after the cold preservation, although a reduction was observed during the subsequent perfusion period. Liver glycogen content in fed rats was markedly higher than in the fasted rats at each time point studied. In fasted and fed rats, liver viability parameters and hepatocyte function were moderately altered, whereas liver endothelial cell function was markedly impaired after cold preservation. However, feeding had no influence on either hepatocyte or liver endothelial cell functions which were similarly altered in both nutritional conditions. The present data show that the nutritional status of liver donors does not play an important role in the preservation of liver endothelial cells after cold ischemia-reperfusion and, thus, should not affect the overall resistance of livers to hypothermic-ischemic injury.
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PMID:Cold ischemia-reperfusion injury of the liver. Role of the liver donor nutritional status in rats. 762 37

Prostanoids such as prostacyclin and thromboxane A2 have recently been suggested to play important roles in cold ischemia/reperfusion injury. The purpose of this study was to investigate the effect of thromboxane A2 synthetase inhibitor (OKY-046) on cold-stored livers of the rat using an ex vivo perfusion system. Addition of OKY-046 to preservation solution and the perfusate of livers stored cold (4 degrees C) in lactated Ringer's solution resulted in significantly lower glutamic pyruvic transaminase release (3.01 +/- 0.86 IU/g liver vs. 1.79 +/- 1.08 IU/g liver at 120 min after perfusion; P < 0.05), reduced perfusate ammonia levels (8.51 +/- 2.51 micrograms/dl/g liver vs. 3.62 +/- 1.71 micrograms/dl/g liver at 60 min; P < 0.05 and thereafter), lower perfusate taurocholate levels (0.63 +/- 0.10 vs. 0.18 +/- 0.05 at 15 min; P < 0.01 and thereafter), perfusate hyaluronic acid clearance (0.934 +/- 0.132 vs. 0.76 +/- 0.127 at 30 min; P < 0.05 and thereafter), and a reduced number of trypan blue-positive sinusoidal lining cells (50.1 +/- 9.9%; vs. 17.4 +/- 7.0%; P < 0.01). Histologically, the liver preserved for 6 hr in simple cold lactated Ringer's solution exhibited interstitial edema, various degrees of hepatocyte swelling, and sinusoidal stenosis, as well as dilatation, while the livers treated with OKY-046 demonstrated much less hepatocyte swelling, and change in sinusoidal width was nearly absent. We conclude that OKY-046 reduces post-preservation reoxygenation injury by protecting sinusoidal endothelial cells and hepatocytes.
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PMID:Beneficial effect of thromboxane A2 synthetase inhibitor on cold-stored rat liver. 794 Jul 9

Liver endothelial cells appear to be particularly vulnerable to cold ischemia reperfusion. However, their function has not yet been evaluated, except using electron microscopic changes and trypan blue exclusion (an index of cell death). Hyaluronic acid is a polysaccharide highly extracted by normal liver endothelial cells. We thus evaluated liver endothelial cell function by measuring hyaluronic acid elimination in a model of ischemia-reperfusion injury using isolated perfused Wistar rat livers. We compared the effects of two preservation solutions during cold ischemia (4 degrees C): normal saline with 2 mM CaCl2 (4 h and 8 h ischemia) and the University of Wisconsin solution (8 h and 24 h ischemia). Eliminations were measured during two 40-min periods before and after ischemia; during each period, hyaluronic acid (150 ng/ml) and also, to evaluate hepatocyte function, propranolol (100 ng/ml) were infused into the reservoir. We show that, whatever the preservation solution or time used, liver endothelial cell function is altered to a larger extent than hepatocyte function. University of Wisconsin solution does not appear to protect liver endothelial cells during preservation, particularly after 24 h of cold ischemia. Hyaluronic acid elimination can be a useful tool in the investigation of an ideal preservation solution to protect liver endothelial cells from ischemia-reperfusion damage.
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PMID:Metabolism of hyaluronic acid by liver endothelial cells: effect of ischemia-reperfusion in the isolated perfused rat liver. 807 37

It is well recognized that current selection criteria used to assess liver grafts before implantation are inaccurate and correlate poorly with graft outcome. A bench or laboratory-based test that could indicate the extent of liver injury immediately before implantation would be a valuable adjunct to clinical assessment. Hyaluronic acid (HA) and creatine kinase (BB component; CK-BB) levels in the caval effluent after liver perfusion have been suggested as indicators of preservation injury. Our objective was to investigate the relevance of preserved liver effluent HA and CK-BB as a predictor of early graft function. Perfused liver effluent HA and CK-BB levels were measured. Graft function was measured in terms of peak serum aspartate transaminase and its level on day 5 postoperatively as well as peak bilirubin level and prothrombin time. The cold ischemia time (CIT) was recorded. Statistical comparisons were made among HA level, CK-BB level, CIT, and graft function parameters. The study was conducted at The Liver and Hepatobiliary Unit, Queen Elizabeth Hospital, Birmingham, United Kingdom. Fifty patients undergoing OLT were studied. HA level was measured in 50 patients and CK-BB level in 30 patients. The main outcome measures were graft function and graft outcome. The graft function data are grouped according to effluent HA levels above or below 400 micrograms/L. Thirteen patients (26%) had a level below 400 micrograms/L and the remaining 37 (74%) were above this threshold. There were no significant differences between the groups for these indicators of graft function. There was no difference between the 2 groups for CIT. The overall median HA level was 1212 micrograms/L (range 39-4000 micrograms/L). The median total CK activity in the perfusate was 302 IU/L (range 118-1155 IU/L). The proportion of CK-BB activity from this total was 146 IU/L (8-641 IU/L), or 48% of the total CK activity. In a multiple regression analysis with CK-BB activity as the dependent variable, there was no demonstrable numerical relationship to graft function. In a separate multiple regression analysis similar results were obtained for HA. We conclude that the level of HA or CK-BB levels should not be used in determining the suitability for implantation of a harvested hepatic allograft.
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PMID:Can effluent hyaluronic acid or creatine kinase predict sinusoidal injury severity after cold ischemia? 827 99

Evidence has accumulated that oxygen-derived free radicals contribute to the cellular damage induced by ischemia-reperfusion. It has been suggested that nitric oxide (NO) may act as a protective factor in ischemia-reperfusion injury since NO increases blood flow and may scavenge oxyradicals. Nevertheless, controversy exists as to the role of NO. This study was designed to clarify the role of endogenous NO in ischemia-reperfusion-induced liver injury in rats in vivo. Wistar rats weighing 250-300 g were divided into three groups: (1) untreated group (Control); (2) NG-nitro-L-arginine, a specific inhibitor of NO production (L-NNA); and (3) L-arginine-pretreated L-NNA group (AR+L-NNA). Occlusion of all vessels to the median and left hepatic lobes (60 min) was followed by reperfusion for 1 or 24 hr. L-NNA was administered before ischemia as a 10 mg/kg bolus. L-Arginine was given just before L-NNA administration as a 100 mg/kg bolus. Administration of L-NNA resulted in endothelial cell injury characterized by the elevation of serum hyaluronic acid as well as the reduction of hepatic tissue blood flow, and the recovery of hepatic adenosine triphosphate was depressed compared with the control after both 1 and 24 hr of reperfusion. Furthermore, the leakages of various liver enzymes and lipid peroxide were also increased, associated with histological damage. This effect of L-NNA was completely abolished by pretreatment with L-arginine. These results suggest that endogenous NO provides a protective effect against ischemia-reperfusion injury in rat liver.
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PMID:Role of endogenous nitric oxide in ischemia-reperfusion injury in rat liver. 853 80

The onset of warm ischemia and reperfusion injury in the liver was investigated in a canine model through changes in parenchymal markers [isozyme class V of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT)], endothelial markers [purine nucleoside phosphorylase (PNP) and hyaluronic acid clearance], and the liver metabolism (ketone body ratio) in warm ischemia induced by inflow occlusion using Pringle's maneuver and subsequent reperfusion. In this in vivo model, a PNP assay system and a model were designed so as to exclude the influence of wide localization of PNP possibly originating in erythrocytes or the intestine, and to discriminate between PNP of endothelial cells and that of parenchymal cells in the liver. After 45 min of warm ischemia, reperfusion resulted in damage only to endothelial cells, as seen by significant increase in PNP alone (3.6 +/- 0.1 U/liter at the end of warm ischemia to 6.8 +/- 0.5 U/liter at 5 min after reperfusion, P < 0.01) and significant decrease in hyaluronic acid clearance compared to the 30-min warm ischemia group in which no increase in either marker for parenchymal and endothelial cells was noted. By contrast, after 60 min of warm ischemia, reperfusion resulted in damage to parenchymal cells along with damage to endothelial cells, as seen by significant increases in LDH(V) and ALT (93 +/- 4 U/liter and 32 +/- 2 IU/liter at the end of warm ischemia to 239 +/- 17 U/liter and 165 +/- 27 IU/liter at 5 min after reperfusion, respectively), as well as a marked increase in PNP and deterioration of hyaluronic acid clearance compared to the 45-min warm ischemia group. Reperfusion after 120 min of warm ischemia did not show recovery of metabolic function of the liver as evaluated by hepatic mitochondrial redox state. It is suggested that a time lag occurs in the onset of injury between parenchymal cells and endothelial cells and that endothelial cells are temporally earlier in failing than parenchymal cells when the liver is exposed to short-term warm ischemia and subsequent reperfusion.
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PMID:Difference in onset of warm ischemia and reperfusion injury between parenchymal and endothelial cells of the liver. Evaluation by purine nucleoside phosphorylase and hyaluronic acid. 860 98

Twenty-four porcine orthotopic liver transplantation were performed using temporary portal vein arterialization technique in an attempt to investigate (1) the influence of warm ischemia time of the donor liver on recipient survival and (2) significance of intraoperative changes of GOT, hyaluronic acid (HA), and amount of bile excretion for graft viability. The animals were divided into three groups according to warm ischemia time; group I (0 min, n = 9), group II (30 min, n = 8), and group III (60 min, n = 7). In group I all the animals survived more than 4 days, while in group II all died within 30 hours due to graft failure. In group II there were survivors (4 pigs lived for 2, 5, 6, 14 days) and non-survivors (4 pigs died within 12 hours). Although GOT values of groups II and III were significantly higher than those of group I after revascularization of the grafted liver, there was no difference between group II and III. There was also no difference between survivors and non-survivors in group II. HA values showed steep increase during operation in all three groups, but there were no differences among them. Bile was collected for 90 minutes after revascularization of the donor liver, and the amount in group I was significantly higher than those in groups II and III. Furthermore, comparing survivors and non-survivors in group II, the former excreted significantly more bile than the latter. In our experimental settings, it could be concluded that (1) 30 minutes of warm ischemia was an upper limit for recipient survival, and (2) the amount of bile excretion during 90 min after revascularization of the donor liver reflected the graft viability whereas intraoperative changes of GOT and HA did not.
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PMID:[Porcine liver transplantation using warm ischemic grafts]. 880 72


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