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

Superoxide dismutases (SOD) and their changes in diabetes, aging, ischemia and cancer were studied, Cu, Zn-SOD undergoes glycation reaction in vitro and in vivo and loses its activity by formation of Amadori compounds. Two lysine residues of Cu, Zn-SOD, Lys-122 and Lys-128 are primary glycated sites which are located on the surface of the molecule. The sites are also located on the active site liganding loop which plays a major role in the activity. The glycated Cu, Zn-SOD increased in the red cells of diabetic patients, especially those with diabetic complications. Mn-SOD appears in the serum of patients with acute myocardial infarction in a biphasic manner. The enzyme appears in sera 16 hr and 108 hr after the attack as determined by ELISA. The Mn-SOD levels are also increased in the serum of patients with epithelial ovarian cancer and it is a good marker for detecting and monitoring this cancer. Mn-SOD may play an important role in the ischemic and cancer tissues.
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PMID:[Superoxide dismutases: significances in aging, diabetes, ischemia and cancer]. 223 47

Rats with a portacaval anastomosis and ligation of the hepatic artery 2 days later were infused for 6 hr with a 10% glucose solution (group I) or the same solution combined with 0.24 M/liter branched-chain amino acids (BCAA, group II). Control animals with portacaval anastomosis and sham-operation (group III) or two sham-operations (group IV) were infused with a 10% glucose solution. The rats were killed by decapitation and indoleamines and amino acids were determined in the brain. Rats with liver ischemia were stuporous at the end of the experiment irrespective of treatment. The concentrations in the cortex of lysine, methionine, phenylalanine, threonine, alanine, glutamine, glycine, histidine, and tyrosine were significantly increased in group I compared to group IV. Infusion of BCAA to rats with liver-ischemia (group II) resulted in significantly lower concentrations of lysine, methionine, phenylalanine, threonine, histidine and tyrosine and increased concentrations of isoleucine, leucine, valine, and arginine compared to group I. The content of serotonin in the cortex and brain stem was significantly increased in group I compared with the BCAA-treated animals (group II) and the control groups III and IV. The concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in the cortex and brain stem were higher in group I than in group IV. Infusion of BCAA to rats with liver ischemia normalized the concentrations of 5-HIAA in the cortex and brain stem.
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PMID:Amino acids and indoleamines in the brain after infusion of branched-chain amino acids to rats with liver ischemia. 242 87

Published evidence suggests that ischemia-induced cell swelling renders myocytes vulnerable to plasmalemmal disruption and consequent cell death. Alterations to the myocyte cytoskeleton may be involved in the pathogenesis of this plasmalemmal injury. One putative cytoskeletal structure in cardiac muscle that has received little consideration is the subplasmalemmal network of periodic densities with linking microfilaments termed leptomeres or leptofibrils. We demonstrate these structures in dog heart papillary muscle and describe the improvement in their definition brought about by tissue fixation at 37 degrees C in 2% glutaraldehyde with addition of 0.05 M lysine-HCl, followed by brief postfixation with osmium tetroxide. Alterations to leptomeres during ischemic injury were examined in myocardium subjected to total in vitro ischemia for 30-180 min at 37 degrees C. Leptomeres showed little morphological alteration during the first 90-120 min, after which leptomere periodic densities (striae) increased in size, from 10-20 to 50-80 nm, and were more densely stained. The leptomeres eventually (150-180 minutes) lose definition. The course of these alterations coincided with the appearance of ultrastructural evidence of irreversible ischemic injury to the myocytes.
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PMID:Alterations to subplasmalemmal leptomeres in adult canine myocytes during total in vitro ischemia. 275 77

Low dose urokinase-lys plasminogen was used to treat 10 patients with acute ischemia of lower limbs. Preliminary results are reported and indications defined, the combination producing effective relief and being very well tolerated biologically and clinically. All patients presented clear signs of ischemia provoking a short term risk for the limb. Direct femoral puncture arteriography of the ischemic limb was an essential pretreatment investigation. A thin catheter left in contact with the thrombus allowed localized fibrinolysis to be performed. Follow up arteriography examinations assessed clinicopathologic results, while biologic surveillance of principal coagulation parameters showed a lack of significant alterations during treatment. Ischemic signs were totally relieved in 7 cases, with arterial repermeabilization allowing recuperation of one (3 cases) or both (2 cases) distal pulses. Persistence of a popliteal thrombus in one case required a fogarty after a direct approach and the limb was saved. Two patients had to be amputated because of delayed treatment. These encouraging results suggest that this procedure of local thrombolysis be reserved for popliteal or infra-popliteal occlusions accompanied by sensory-motor signs and of recent (less than 72 hours) onset. Follow up for 8 months is insufficient but has shown the absence of deterioration, but this is obviously a function of the natural course of the underlying atheromatous disease.
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PMID:[Indications and results of combined urokinase-lys plasminogen in acute ischemic pathology of the legs]. 409 20

The levels of amino acids in 6 regions of the brain (cortex, hippocampus, striatum, diencephalon, stem and cerebellum) were determined during an ischemic insult of 30 min and after recovery periods of up to 10 h. The results were analyzed in two groups: putative neurotransmitters (GABA, aspartate, glutamate, taurine, glycine and alanine) and non-neurotransmitters. In the neurotransmitter group, it was found that at the end of 30 min ischemia the levels of aspartate and glutamate slightly decreased whereas those of GABA and alanine rose substantially. The amounts of glycine and taurine remained unchanged. In 30 min after the ischemic insult, there were much larger decreases in aspartate and glutamate and increases in GABA and alanine with no change in glycine and taurine. At 2 h recovery the levels of the neurotransmitter amino acids had almost returned to control values and were fully recovered by 10 h after ischemia. It is postulated that glutamate and aspartate are released during ischemia into the extracellular space and subsequently 'washed-out' into the blood during the reperfusion. Release of GABA, if it occurs, is however, compensated by increase in its synthesis and decrease in its degradation under anaerobic conditions, both of which contribute to the rise in its steady-state level. In the non-transmitter category, increases were seen in amino acids present normally in very small concentrations; tyrosine, lysine, leucine and 3 hydrophobic amino acids: valine, methionine and phenylalanine, which were most pronounced at 2 h after ischemia. It is suggested that the rise in the levels of these molecules is the consequence of stimulation of protein breakdown caused by activation of intracellular proteases by calcium and H+ during the ischemic episode. Regional variations in the patterns of changes were small although in the ischemic models used the brainstem seemed to be least affected.
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PMID:Neurotransmitter amino acids in the CNS. I. Regional changes in amino acid levels in rat brain during ischemia and reperfusion. 614 83

Although acute perfusion of guinea pig hearts with ethanol does not affect cardiac protein synthesis, the latter is inhibited after prolonged ingestion of ethanol when tested in an in vitro system with the working right ventricle. This study reports on the added stress of ischemia on such hearts. Hearts were removed from maturing guinea pigs after 13-16 weeks of ingesting 10% ethanol and were perfused in vitro under conditions of relative ischemia (one-sixth of normal coronary flow) with maintenance of right ventricular load and outflow resistance identical to normal pre-ischemic levels. With this degree of ischemia, there was a 4-6 fold increase in lactate production, an 80% drop in ATP, and a 90% decrease in creatine phosphate after 150 min of the ischemia. Incorporation of both labeled lysine and phenylalanine into cardiac protein was also diminished to 35% of control in the left ventricle and 55% of control in the right. This diminution of protein synthesis was the same in hearts from ethanol-drinking and matched control animals. Thus, prior prolonged ingestion of ethanol did not worsen the inhibition of protein synthesis by oxygen deprivation. There were, however, two significant differences in hemodynamic response to the ischemia by the right ventricles of hearts from ethanol-drinking guinea pigs compared to their matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prolonged feeding of ethanol to the young growing guinea pig. II. A model to study the effects of severe ischemia on cardiac protein synthesis. 642 90

Reactions from the rectal mucosa often give rise to troublesome side-effects during and after radiotherapy in the pelvic region. Local vasoconstriction in the rectal mucosa will cause an ischemia which will decrease the sensitivity of the mucosal cells to radiation and thereby these side-effects can be reduced. Triglycyl-lysine-vasopressin applied rectally in 1% Blanose solution gave in the present study significant radioprotection of the rectal mucosa in the doses of 0.8, 1.6, and 3.2 mg. These doses are, however, very high. Triglycyl-lysine-vasopressin in 1.2% Natrosol solution in a dose of 128 micrograms did not show any certain protective effects. However lysine-vasopressin in 1.2% Natrosol solution in a dose of 16 micrograms gave significant radioprotection of the rectal mucosa. This dose level has in a previous study not given any significant effects on the systemic circulation. Lysine-vasopressin in Natrosol solution seems to be a suitable combination for further studies.
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PMID:Radioprotective effect of local administration of lysine-vasopressin and triglycyl-lysine-vasopressin on the rectal mucosa in rats. 760 56

The function of the N-methyl-D-aspartate (NMDA)-preferring glutamate receptor can be regulated by extracellular pH, a process that may be important during ischemia in the brain or during seizures. Protons inhibit NMDA receptor function by 50 percent at pH 7.3 through interactions with the NR1 subunit, and both polyamines and NR1 exon 5 potentiate receptor function through relief of the tonic proton inhibition present at physiological pH. A single amino acid (lysine 211) was identified that mediates the effects of exon 5 in the rat brain. Electroneutral substitutions at this position restored pH sensitivity and, consequently, polyamine relief of tonic inhibition. This effect, together with the structural similarities between polyamines and the surface loop encoded by exon 5, suggest that exon 5 may act as a tethered pH-sensitive constitutive modulator of NMDA receptor function.
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PMID:Control of proton sensitivity of the NMDA receptor by RNA splicing and polyamines. 775 71

One approach to the development of an effective red cell substitute has been chemical modification of human hemoglobin to optimize oxygen transport and plasma half-life. Human hemoglobin A0 and two of these modified hemoglobins, one prepared from the cross-linking of the alpha-chains at lysine residue 99 by bis(3,5-dibromosalicyl)fumarate (Hb-DBBF) and the other by acylation of lysine residue 82 of the beta-chain by mono-(3,5-dibromosalicyl)fumarate (Hb-FMDA), were tested by HPLC for their susceptibility to oxidative damage caused by H2O2. Such oxidative insult may occur during ischemia and reperfusion of tissues after transfusion of red cell substitutes to patients with hypovolemic shock and trauma. Hb-DBBF was extremely susceptible to damage of its heme and protein moieties with stoichiometric amounts of H2O2, whereas Hb-FMDA was highly resistant, even at 10-fold molar excess and at an acidic pH of 4.7. Hemoglobin A0 was of intermediate susceptibility, exhibiting alteration of heme and protein moieties at acidic but not neutral pH. Since the degradation of heme can release the potentially toxic agent iron, Hb-FMDA may be a more promising candidate than Hb-DBBF for development as a red cell substitute. A similar approach may be used to assess the susceptibility of other hemoglobin-based red cell substitutes to oxidative damage in order to determine the molecular basis of heme and protein alteration.
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PMID:Differential susceptibilities of the prosthetic heme of hemoglobin-based red cell substitutes. Implications in the design of safer agents. 827 64

Oxygen-derived free radicals are known to take part in cardiac injury during post-ischemic reperfusion (I/R). Xanthine oxidase (XO) is closely associated with the generation of superoxide radicals. We have determined the distribution of XO in rat myocardium after ischemia (I) and I/R by immunocytochemical method using murine monoclonal antibody against XO (bovine milk) and by enzyme histochemistry (EHC) in situ. Frozen sections of periodate-lysine-paraformaldehyde (PLP) fixed myocardium after 15, 60 and 90 min ischemia and 15 min ischemia and 30 min reperfusion were processed for immunocytochemistry and EHC. In other experiments, rats were treated with allopurinol, an inhibitor of XO, and hearts were processed for immunocytochemistry. By immunoperoxidase and immunofluorescence methods, a deep staining of interstitial cells, capillary and small blood vessels was observed, but the staining intensity of these cells was increased after reperfusion, in comparison to the normal and ischemic heart tissue. In the electron microscope, an immunoperoxidase reaction product was seen in the cytoplasm of interstitial, endothelial and smooth muscle cells. Similarly, EHC studies by nitroblue tetrazolium staining showed an increase in enzymatic activity in the tissue after reperfusion. The allopurinol-treated I/R tissue exhibited reduced staining. The data suggest that XO activity increases during ischemia but intensifies after reperfusion. The enzyme is localized in interstitial cells, coronary vessel endothelium and smooth muscle cells. XO is constantly present in the interstitial cells of the myocardium and it is a new finding not previously reported. It is further suggested that myocardial interstitium may be one of the major sites where oxygen derived radicals are generated during ischemia.
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PMID:Subcellular distribution of xanthine oxidase during cardiac ischemia and reperfusion: an immunocytochemical study. 832 24


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