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

Kidney preservation under mild hypothermic conditions (24 degrees C) was performed to preserve organs for a long time, to determine the viability of damaged organs, and to evaluate the viability of organs that have previously been stored in cold solution. Rabbit kidneys were perfused via the renal arteries. The perfusate was composed of glucose, allopurinol, PEG-SOD, adenosine, dexamethasone, insulin, HES and FC-43. This solution was an attempt to simulate the electrolyte constitution of extracellular fluid (pH 7.40 delta pH). The functions of all groups of kidneys were evaluated by measuring urine output, urine pH and urine electrolytes. The suitable perfusion pressure was 80 mmHg. The kidneys without a warm ischemic period were well stored and functioned for over 12 hours under 24 degrees C perfusion. In the warm ischemic groups, the viability and histological structure of the kidneys were well maintained and conditioned for 12 hours at up to 35 min of warm ischemia. The kidneys which were stored in 4 degrees C UW-solution for 24 hours had a good urination using mild hypothermic perfusion for 12 hours. This suggest that mild hypothermic perfusion will become a useful method for preserving the condition of organs and for determining and evaluating the viability of organs that have previously been stored in cold solution.
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PMID:[Experimental studies on functional preservation, conditioning and evaluation of the viability of rabbit kidneys utilizing mild hypothermic perfusion]. 805 26

The aim of this study was to optimize the properties of a lubricious bioerodible hydrogel barrier for the prevention of postoperative adhesions. Water-soluble macromers based on block copolymers of poly(ethylene glycol) (PEG) and poly(lactic acid) or poly(glycolic acid) with terminal acrylate groups were used, and these macromers were gelled in vivo by exposure to long wavelength ultraviolet light. The precursor was photopolymerized from buffered saline solution while in contact with the tissues. This resulted in the conformal coating of the tissue with an adherent hydrogel film, while forming a nonadhesive barrier at the free surface, on the treated wound site. The hydrogels were evaluated in two animal models of postsurgical adhesions, first in a rat cecum abrasion model and then in a rabbit uterine horn ischemia model. In the rat cecum model, six of seven animals treated with a hydrogel, with glycolide in the precursor as the comonomer, showed no adhesions; untreated animals and animals treated with precursor, but not gelled with light, showed consistent dense adhesions. In the rabbit uterine horn ischemia model, using hydrogels with lactide in the precursor as the comonomer, and PEG of molecular weight from 6,000 to 18,500 Da, adhesions were dramatically reduced, with occurrence in none of seven animals treated with a gel containing PEG 10,000. By contrast, the seven animals in the control group demonstrated a mean of 35% involvement of the horn length in dense, fibrous adhesions. These materials, photopolymerized in vivo in direct contact with the tissues, appear to form an adherent hydrogel barrier that is highly effective in reducing postoperative adhesions in the models used.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Optimization of photopolymerized bioerodible hydrogel properties for adhesion prevention. 808 51

We tested the hypothesis that administering polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) either before global cerebral ischemia or at the time of reperfusion would alter recovery of cerebral blood flow (CBF; microspheres) response to alteration in arterial PCO2 in pentobarbital-anesthetized, mechanically ventilated piglets (1 to 2-wk old). CBF was measured at an arterial PCO2 of approximately 3.3, 5.3, and 8.7 kPa before and 2 h after ischemia (10 min aortic cross clamp). To determine the effect of preischemic versus postischemic treatment with PEG-SOD, each piglet received two i.v. drug injections of either 30,000 U PEG-SOD or an equal volume of PEG diluent in a randomized, blinded fashion before ischemia and just before reperfusion. Cerebral oxygen consumption and somatosensory evoked potentials were measured during reperfusion as an assessment of brain function. During reperfusion, no group demonstrated delayed hypoperfusion. Hypercapnic CBF was less during reperfusion (48 +/- 6 mL/min/100 g) compared with preischemia (69 +/- 10 mL/min/100 g) in PEG/PEG-treated piglets. However, hypercapnic CBF during reperfusion was not different from preischemic values with either preischemic or postischemic PEG-SOD treatment. Improved return of hypercapnic CBF in PEG-SOD-treated piglets was not attributable to improved postischemic cerebral oxygen consumption. Somatosensory evoked potential amplitude was decreased similarly during reperfusion (approximately 25% of preischemic values) in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Polyethylene glycol-conjugated superoxide dismutase improves recovery of postischemic hypercapnic cerebral blood flow in piglets. 825 89

Generation of free radicals during reperfusion after organ ischemia has been implicated in the pathogenesis of ischemic injury. We have previously shown that a combination of intravenous polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) and catalase (PEG-CAT), at a dose of 10,000 U/kg each, is effective in reducing infarct size in a focal cerebral ischemia model in the rat. It is not clear whether PEG-SOD alone is sufficient to reduce ischemic brain injury. In this study we determined the therapeutic efficacy of PEG-SOD and its dose-response curve. In a range of 1,000-30,000 U/kg, PEG-SOD exhibited a U-shaped dose-response curve. Only 10,000 U/kg significantly reduced infarct size [control 121 +/- 12 mm3 (mean +/- SE), n = 35; PEG-SOD 95 +/- 10 mm3, n = 36, P < 0.05]. PEG-SOD at the doses tested did not have significant acute hemodynamic effects but had a tendency to improve postischemic hypotension. This beneficial effect of PEG-SOD on blood pressure did not appear to fully account for the treatment effect of PEG-SOD on infarct size. The narrow therapeutic dose range of PEG-SOD in this study and similar findings of SOD in other investigations may contribute to the inconsistent protective effects of SOD preparations in ischemia-reperfusion injury in the literature.
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PMID:Polyethylene glycol-conjugated superoxide dismutase in focal cerebral ischemia-reperfusion. 834 41

Electron paramagnetic resonance (EPR) spectroscopy was used to directly measure free radical generation in ischemic/reperfused diabetic rat retina. Tissue was frozen at 77 degrees K after 90 min ischemia, and 90 min ischemia followed by 1 min, 3 min, 5 min, and 24 hours reperfusion, respectively. After 90 min of ischemia followed by 1 min, 3 min, 5 min, and 24 hours of reperfusion (n = 10 in each group), free radical signal intensity was increased from its diabetic nonischemic control value of 12 +/- 3 arbitrary units to 58 +/- 6 (P < 0.05), 62 +/- 7 (P < 0.05), 32 +/- 5 (P < 0.05), and 14 +/- 4 arbitrary units, respectively. The peak intensity of free radical production was observed after 90 min ischemia followed by 3 min of reperfusion; therefore, this time point was selected to study the retinal free radical production in superoxide dismutase (conjugated with polyethylene glycol, PEG-SOD) and EGb 761 (Ginkgo biloba extract)-treated groups. With 7,500, 15,000, and 30,000 U/liter of SOD, and 25, 50, and 100 mg/kg of EGb 761, a dose-dependent reduction in oxygen free radical production was detected, respectively, which may be responsible for the attenuation of abnormal postischemic function in ischemic and reperfused diabetic retina.
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PMID:Direct measurement of free radicals in ischemic/reperfused diabetic rat retina. 929 50

By means of a simplified questionnaire, the NADYA group has gathered and analyzed data with regard to the age, sex, diagnosis, access route, duration, form of administration, complications, and quality of life, in 812 patients (62% male; 37% female) with At Home Enteral Nutrition (AHEN), and 19 patients (42% male; 57% female) with At Home Parenteral Nutrition (AHPN) corresponding the National Registry of 1995. The most frequent indication of AHEN was a neoplasm (41%), followed by neurological alterations (33%). The most common access route is the NGT (37%) followed by oral administration in 37%, PEG in 13% and surgical ostomics in 8%. The mean treatment time is 8 months. The index of complications/patient-year is 0.50 (gasterointestinal 0.17, and mechanical alterations 0.9). At the end of the study, 63% of the patients continued to receive AHEN, showing a mortality rate of 70%. The majority of the patients undergoing treatment presented a sever social disability (20%) or were bed ridden (18%). The most common indications for the AHPN are: radical enteritis (26%), Crohn's disease (21%), and mesenteric ischemia (16%). AIDS, motility alterations, and neoplasic diseases are scantly represented (10%). Tunneled catheters are used in 58% of the cases, and Port-a-Cath in 31%). The mean duration for the treatment was 7.9 months. An index of 0.47 hospitalization/patient-year was seen in relation to the nutritional treatment (mainly due to catheter septicemia). A mortality of 16% is noted, and 21% show a recovery of the oral route. 42% of the patients did not present an assessable social disability.
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PMID:[Artificial nutrition in the home. 1995 yearly report. NADYA-SENPE Group (Natiional Registry of Patient-Spanish Society for Parnteral and Enterlal Nutrition]. 966 56

We characterized the changes in nitric oxide (NO) levels in the brain during global forebrain ischemia and reperfusion and tested the ability of the natural flavonoid, quercetin, and a synthetic flavonoid, FB277, to increase the amount of available NO by elimination of the superoxide radicals produced during reperfusion. In Sprague-Dawley rats, we used a four-vessel occlusion model of forebrain ischemia (15 min) and reperfusion (30 min). Brain NO was measured on samples of cerebral cortex and cerebellum ex vivo by electron paramagnetic resonance (EPR) spectroscopy. The spin trap used was diethyldithiocarbamate sodium salt (DETC) associated with ferrous citrate. The complex Fe(DETC)2NO was detected at 77 K as a triplet signal at g = 2.035. Groups of animals were treated with quercetin or FB277 (3-morpholinomethyl-3',4',5,7tetramethoxyflavone) or polyethylene glycol-conjugated superoxide dismutase (PEG-SOD). In control (intact anesthetized animals), the signal was about 3 times greater in the cortex than in the cerebellum. During ischemia, the signal rose to 110% in cortex (NS) and 283% in cerebellum (P < 0.05). In reperfusion, it fell again to 91% of control in cerebellum (NS) and 35% in cortex (P < 0.05). Treatment by quercetin (5 mg/kg i.v.) of intact and ischemia-reperfusion groups did not significantly change the signal amplitude in the cerebellum, but did double it in the cortex (to 76% of control) for the ischemia-reperfusion group (P < 0.05). In contrast, FB277 (3.75 mg/kg i.v.) did not increase the signal in the cortex during ischemia-reperfusion, but did do so in the cerebellum (to 152% of control, P < 0.05). The results obtained for PEG-SOD (10,000 U/kg i.v.) were similar to those for FB277. In separate in vitro measurements, we found that quercetin but not FB277 efficiently scavenged superoxide. We hypothesize that quercetin but not FB277 scavenged superoxide anions released in the cortex during reperfusion, thus diminishing the amount of NO removed by the formation of peroxynitrite. The lack of effect of PEG-SOD may be related to the need for chronic treatment to obtain protection.
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PMID:Influence of the antioxidant quercetin in vivo on the level of nitric oxide determined by electron paramagnetic resonance in rat brain during global ischemia and reperfusion. 989 May 69

Four types of bovine liver catalase (CAT) derivatives, succinylated (Suc-CAT), galactosylated (Gal-CAT), mannosylated (Man-CAT), and polyethylene glycol conjugate (PEG-CAT), were synthesized and their pharmacokinetics and therapeutic potential in a hepatic ischemia/reperfusion injury model were studied in mice. About 90% of the CAT enzymatic activity was retained after chemical modification. Biodistribution studies showed that 111indium (111In)-Gal-CAT accumulated selectively in the liver parenchymal cells as 111In-CAT, whereas an increased amount of 111In-Suc-CAT and 111In-Man-CAT was delivered to liver nonparenchymal cells. 111In-PEG-CAT exhibited prolonged retention in plasma. Pharmacokinetic analysis revealed that the hepatic uptake clearances of 111In-Suc-CAT, 111In-Gal-CAT, and 111In-Man-CAT were much greater than that of 111In-CAT, whereas that of 111In-PEG-CAT was very small. In the ischemia/reperfusion injury model, in which hepatic injury was induced by occlusion of the portal vein for 30 min followed by 1 h reperfusion, the elevation of plasma glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels was slightly inhibited by treatment with native CAT or Gal-CAT. PEG-CAT was less potent. In contrast, Suc-CAT and Man-CAT effectively suppressed the increase in plasma glutamic pyruvic transaminase and glutamic oxaloacetic transaminase. Coinjection of mannosylated superoxide dismutase marginally improved the inhibitory effects of CAT derivatives. These results demonstrate that targeted CAT delivery to liver nonparenchymal cells via chemical modification is a promising approach to prevent hepatic injuries caused by reactive oxygen species. The potential usefulness of combining of CAT and superoxide dismutase derivatives is also demonstrated.
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PMID:Targeted delivery and improved therapeutic potential of catalase by chemical modification: combination with superoxide dismutase derivatives. 1021 2

Using a simplified questionnaire from the NADYA group, data referring to age, sex, diagnosis, access route, duration, form of administration, complications, and quality of life have been gathered from 1,400 patients (57% male, 43% female) who receive home enteral nutrition, and from 38 patients (20% male and 18% female) who receive home parenteral nutrition. All of these patients come from the 1996 national registry. The most common indication for home enteral nutrition are neoplasias (39%) followed by neurological alterations (33%). The most common access route is oral (48%), followed by a nasogastric tube in 34%, PEG in 10% and surgical ostomies in 7%. The average treatment duration is 6 months. There is an index of 0.74 complications/patient-year (gastrointestinal 0.28 and mechanical alterations 0.19). At the end of the year 58% of the patients continued to use at home enteral nutrition, with a death rate of 17%. The majority of the treated patients presented a severe social disability (28%) or was bed-ridden (22%). The most common indications for home parenteral nutrition are: neoplasia (42%), Crohn_s disease (10%), and mesenteric ischemia (10%). AIDS (8%), radical enteritis (5%), and motility disorders (5%) are less common. In 42% of the cases tunneled catheters are used, and port-a-cath are used in 53%. The average treatment duration is 6.9 months. 1.06 hospitalizations/patient-year have been registered in relation to the nutritional treatment (mainly catheter sepsis). A mortality of 29% is registered, and there is recovery of the oral route in 7.9% of the cases. 50% of the patients present a severe social disability.
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PMID:[Artificial nutrition in the home. Annual information 1996.Group NADYA-SENPE]. 1050 53

The purpose of this study was to evaluate an intracellular solution with polyethylene glycol (PEG, molecular weight 20,000) as an impermeant, compared with University of Wisconsin (UW) and Euro-Collins (EC) solutions, after a 48-h cold storage (CS). The normothermic isolated perfused rat kidney (IPK) technique was used to assess renal function after CS. Five groups were studied: a control group (immediately reperfused, n = 10); one that received EC (n = 16); one that received UW (n = 16); and two that each received an intracellular (IC) solution, one with PEG (ICPEG, n = 16) and one without PEG (IC, n = 16). The perfusion flow rate was significantly greater in the PEG group and correlated with less significant cellular and interstitial edema and lower renal vascular resistance than in the IC, EC, and UW groups. Glomerular filtration rate was significantly higher in the PEG group during reperfusion than in the IC, EC, and UW groups. Proximal tubular functions were more efficient with PEG: fractional sodium reabsorption and total sodium reabsorption were significantly greater during reperfusion in the PEG group than in the IC, EC, and UW groups. Of greater interest is the protective effect of PEG on lipid peroxidation, which reflects ischemia/reperfusion damage. The second major effect is the dramatic ATP restoration during reperfusion, which outlines the preservation of oxidative phosphorylation after preservation by ICPEG. These results are supported by histological studies, particularly concerning brush border and mitochondrial preservation. Our results indicate that PEG is promising for cold ischemia and reperfusion injury protection.
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PMID:Protective effect of polyethylene glycol against prolonged cold ischemia and reperfusion injury: study in the isolated perfused rat kidney. 1135 15


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