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Query: HUMANGGP:001372 (ESR)
 7,313 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seven patients of temporal arteritis with eye involvement have been presented. These cases represent a spectrum of disease from intermittent diplopia with minimal 6th nerve weakness through mild retinal ischemia with recovery to permanent bilateral blindness. Temporal arteritis should be suspected when any form of ocular ischemia is suspected by history or found on examination of an elderly person. An early diagnosis may protect the vision in both eyes if vision is normal at the time of diagnosis. If vision in one eye is decreased because of ischemia, the vision in the other eye can usually be retained if proper therapy is instituted. Furthermore, adequate therapy may even result in improvement in vision in the involved eye. Patients with biopsy proven temporal arteritis should be continued on steroid therapy until the active disease is quiescent. Inactivity should be determined by carefully monitoring the ESR while steroids are being tapered. If the ESR rises, it is indicative of continued inflammation and if steroids are not continued, the eyes remain at risk as seen in Case 5. If the ESR remains elevated for a year or more despite continuation of high steroid levels, consideration should be given to repeating the temporal artery biopsy. Temporal arteritis should be considered in the differential diagnosis of any multisystem disease in older patients. Even central nervous system involvement may occur concomitantly, since the intracranial vessels are not immune from the disease process. Tuberculosis, systemic syphilis and more recently the collagen vascular diseases have been dubbed the "great imitators" and "the protean diseases." We suggest that the same terminology can be applied to temporal arteritis. Temporal arteritis can affect any organ. Moreover, there is a wide spectrum of variation in the degree of involvement of any particular tissue as illustrated by these 7 cases of ocular involvement.
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PMID:Temporal arteritis: a spectrum of ophthalmic complications. 118 Apr 60

Isolated perfused rat heart model was used to observe the protective effects of berbamine on myocardial ischemia/reperfusion injury. The hearts were significantly injured by 40 min global ischemia followed by 20 min reperfusion. Berbamine could significantly improve heart function, prevent ventricular fibrillation, reduce CK release, preserve Na,K-ATPase activity, and reduce Na+ gain and K+ loss during ischemia and Ca2+ overload during reperfusion. With the use of low temperature ESR technique, in hearts subjected to 40 min ischemia and 15 sec reperfusion, oxygen-centered free radical signals became much more intense. In the presence of berbamine, these signals decreased. Results showed that berbamine could alleviate myocardial ischemia/reperfusion injury. This effect might be due to: 1) preserved myocardial Na,K-ATPase activity and inhibition of sodium overload at the end of ischemia, which might further lead to attenuation of reperfusion-induced calcium overload, and 2) reduction of oxygen free radical generation during reperfusion.
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PMID:Mechanisms of protective effects of berbamine on ischemia/reperfusion injury in isolated rat heart. 133 20

The generation of free oxygen radicals is presumed to be a pathogenetic principle in various conditions, primarily in postischemic reperfusion injury. Their assessment is difficult. ESR is an excellent tool to assess free radicals directly. In an experimental model of rat liver ischemia and reperfusion the increased generation of free radicals during reperfusion in liver tissue could be demonstrated after 60 min of liver ischemia. Elevated production rates of radicals could be detected after 5 min of reperfusion for at least 45 min with a maximum after 15 min of reperfusion. Scavenging of these radicals has to start in the very beginning of reperfusion.
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PMID:[Ischemia/reperfusion damage of the liver caused by free radicals--direct radical detection using electron spin resonance (ESR)]. 165 33

The purpose of this study was to find out whether Ca2+ is necessary for the protective effect of phosphocreatine (PCr) on ischemic myocardium. Isolated Langendorff-perfused rat hearts were used in the study. When ischemic arrest was induced in Ca(2+)-free buffer, PCr did not exert a protective effect on ischemic myocardium. PCr improved postischemic contractile recovery of hearts subjected to ischemia in perfusion media containing 0.5 and 1.2 mmol/l Ca2+. Phosphoarginine, a structural analogue of PCr which possesses Ca(2+)-binding property similar to that of PCr did not exert any protective effect on ischemic myocardium. The effects of PCr and Ca2+ on lipid order of sarcolemmal vesicles from canine heart were studied by using ESR spectroscopy. PCr made membrane phospholipids more tightly packed at mildly acidic and neutral pH, but did not at pH 8.5. Although Ca2+ itself did not influence the membrane structure at pH 5.5, it potentiated the effect of PCr on sarcolemmal phospholipids. Thus, the protective effect of PCr on ischemic myocardium is not attributed to its Ca2+ binding properly, but Ca2+ is a necessary component of the mechanism of protective effect of PCr on ischemic myocardium.
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PMID:Participation of calcium ions in the molecular mechanism of cardioprotective action of exogenous phosphocreatine. 165 4

A series of experiments have been done to investigate the role of oxygen free radicals in ischemia/reperfusion injury. The following results were found: Myocardial MDA content increased significantly after post-ischemic reperfusion in vivo and in vitro. A blockade of the xanthine oxidase pathway for free radical generation could provide effective protection against ischemia/reperfusion injury. Exogenous reactive oxygen intermediates H2O2, .OH and O2- could induce changes in the contractility and electrophysiological properties of myocardial cells similar to those seen in ischemia/reperfusion. An outburst of free radical generation was detected by ESR spectroscopy at low temperature (-173 degrees C) and with the spin trapping technique during the very early phase of reperfusion. The authors emphasize the important role of free radicals in the pathogenesis of myocardial ischemia/reperfusion injury.
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PMID:The role of oxygen free radicals in myocardial ischemia/reperfusion injury. 179 73

Using a rat model, we evaluated the effect of SOD on the survival of ischemic reperfused island skin flaps. In experiment 1, the oxygen free radical concentration in the flaps was measured by the technique of ESR. The results showed that the oxygen free radical concentration in ischemic reperfused flaps was significantly higher than in the corresponding control flaps (P less than 0.001). In experiment 2, the flaps were perfused with SOD (2000 U in 1 ml saline) before reperfusion after 8 hours of ischemia. Seven days after operation, the area of flap survived in the test group was significantly larger than in the control group (P less than 0.0005). The obtained data demonstrated that the generation of oxygen free radical increases with time during ischemia reperfusion in island skin flap and the role of oxygen free radical in tissue injury following ischemia and reperfusion. The use of SOD can enhance the survival of ischemic island skin flap.
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PMID:[Effect of superoxide dismutase for improvement of survival of ischemic reperfused island skin flap]. 181 53

Of the available techniques used to identify free radicals, spin-trapping offers the unique opportunity to simultaneously measure and distinguish among a variety of important biologically generated free radicals. For superoxide and hydroxyl radical, the spin trap 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) is most frequently used. However, this nitrone has several drawbacks. For example, its reaction with superoxide is slow, having a second-order rate constant around 10 M-1 s-1. Because of this, high concentrations of DMPO are essential in order to observe the corresponding spin-trapped adduct, 5,5-dimethyl-2-hydroperoxy-1-pyrrolidinyloxy. This may, in some cases, lead to cellular toxicity. In an attempt to circumvent this serious limitation, it has been proposed that an indirect approach be employed to detect and identify free radicals generated as a consequence of ischemia/reperfusion injury. In the direct (most frequently used) approach, the spin trap is first added to an isolated perfused organ under the appropriate experimental conditions. Then, the infusion buffer containing the spin-trap adduct(s) is placed into an quartz flat cell to be inserted into an ESR spectrometer. In the indirect method, the spin trap is added to the perfusate, which had previously exited the organ. Therefore, with this method one can prevent any spin-trap-mediated toxicities to the isolated perfused organ. However, because of the very rapid rate of free radical reactions catalyzed by either superoxide or hydroxyl radical, it is questionable whether ESR spectra recorded using this indirect method result from the actual spin-trapping of free radicals. In this report, we evaluated the indirect spin-trapping technique in light of the kinetic considerations discussed above.
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PMID:Spin-trapping of superoxide by 5,5-dimethyl-1-pyrroline N-oxide: application to isolated perfused organs. 196 76

The real-time kinetics of the release of ascorbyl free radicals in the coronary perfusate from isolated rat hearts submitted to an ischemia/reperfusion sequence has been achieved by continuous-flow ESR using high-speed acquisition techniques. Enhanced ESR detection of ascorbyl free radicals was obtained by addition of dimethyl sulfoxide (Me2SO), a strong cation chelator and oxidizing agent. A continuous-flow device allowed a direct monitoring of the ascorbyl free radical and/or ascorbate leakage in coronary perfusate by observation of the ascorbyl radical doublet (aH = 0.188 mT and g = 2.0054). 1. The results showed that ascorbyl free radical release occurred mainly during sequences of low-flow ischemia (90 min) coupled or not with 30 min of zero-flow ischemia followed by reperfusion (60 min). The kinetic profiles of ascorbyl-free-radical detection confirm in quantitative terms the expected correlation between the duration of the ischemic insult and the magnitude of ascorbate extracellular release upon reperfusion. There is indication that ascorbyl free radical depletion could be secondary to oxygen-derived-free-radical-induced cellular damage. 2. The amount of residual ascorbic acid was quantitated on myocardial tissue at the end of reperfusion using Me2SO as extracting solvent. Intense oxidation of ascorbate and chemical stabilization of the resulting free radical species provided by Me2SO allowed ESR measurement of a marked tissue ascorbate depletion related to the duration of ischemia. 3. Perfusion of superoxide dismutase during low-flow ischemia and the first 10 min of reperfusion greatly inhibited both extracellular release and endogenous ascorbate depletion. These results suggest that the ascorbate redox system constitutes a major protective mechanism against free-radical-induced myocardial injury. 4. The proposed direct ESR detection of ascorbyl free radicals in the coronary perfusates or in tissue extracts does not require extensive chemical preparation and conditioning of effluent or tissue samples. It provides an interesting straightforward alternative to the evaluation of detrimental free radical processes affecting the myocardium during ischemia and reperfusion.
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PMID:Ascorbyl free radical as a reliable indicator of free-radical-mediated myocardial ischemic and post-ischemic injury. A real-time continuous-flow ESR study. 217 67

O2-generation rate (Vo2-) in microsomal, mitochondrial and nuclei liver membranes was measured by ESR method, by accumulation of stable nitroxide radicals. These Vo2- values were compared with Cu, ZnSOD and MnSOD activities after 2 hours ischemia and 24 hours reoxygenation. O2- radicals generated by electron transfer chains are concluded to damage mainly during the ischemia, but not the reoxygenation.
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PMID:[Membranes of subcellular organelles as the source of superoxide radicals in liver ischemia]. 239 90

This review begins with discussion concerning the effects of changes in phospholipid compositions on membrane functions. Next, pathogenetic mechanisms of ischemic cell damage are reviewed; a) membrane phospholipid breakdown, caused by the activation of phospholipases, as well as the intracellular Ca2+ overload, and b) univalent oxygen reduction and lipid peroxidation, probably all play important roles. Consequently, hydrophilic metabolites of lipid peroxidation may accumulate in the hydrophobic membrane bilayer during ischemia, causing membrane dysfunction. Free radicals may involve the cross-linking of membrane proteins as well. Previous results in support of the free radical hypothesis of myocardial ischemic injury are described; they were obtained from ESR studies, measurements of tissue antioxidants, determinations of lipid breakdown products, and studies using scavengers. The distribution, biosynthesis and physical-chemistry of plasmalogens are then discussed. Excepting the platelet activating factor recently discovered, only fragmentary information is available concerning the function of plasmalogens. It is possible that membrane plasmalogens, which contain large amounts of polyunsaturated fatty acids, are vulnerable to free radical/ischemic injury.
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PMID:Membrane phospholipids and plasmalogens in the ischemic myocardium. 242 80


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