Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The goal of this study was to test the hypothesis that the cardioprotective effects of the late phase of ischemic preconditioning (PC) can be mimicked by treatment with NO donors. In phase I (studies of myocardial stunning), conscious rabbits underwent a sequence of six 4-minute coronary occlusion/4-minute reperfusion cycles for 3 consecutive days (days 1, 2, and 3). In group I (controls, n=6), the total deficit of systolic wall thickening (WTh) after the sixth reperfusion was reduced by 54% on days 2 and 3 compared with day 1 (P<0.05), indicating a late PC effect against myocardial stunning. When rabbits were given the NO donors diethylenetriamine/NO (DETA/NO, 0.1 mg/kg i.v., 4 times [group II, n=5]) or S-nitroso-N-acetylpenicillamine (SNAP, 2.5 microg x kg(-1) x min(-1) i.v. for 75 minutes [group III, n=51) 24 hours before the first sequence of occlusion/reperfusion cycles, the deficit of WTh on day 1 was 60% (group II) and 54% (group III) less than that observed in controls (P<0.05 for both). In both groups II and III, there was no further improvement in the deficit of WTh on days 2 and 3 compared with day 1. The protective effect of DETA/NO was completely abrogated when this agent was given in conjunction with the ONOO- and .OH scavenger mercaptopropionyl glycine (MPG) (group IV, n=5). In phase II (studies of myocardial infarction), conscious rabbits underwent a 30-minute coronary occlusion followed by 3 days of reperfusion. When rabbits were preconditioned 24 hours earlier with six 4-minute occlusion/4-minute reperfusion cycles, infarct size was reduced by 43% (33.2+/-2.7% versus 58.3+/-4.1% of the region at risk in controls, P<0.05), indicating a late PC effect against myocardial infarction. When rabbits were pretreated with DETA/NO (group VII, n=8) or SNAP (group IX, n=7) 24 hours before the 30-minute occlusion, infarct size was reduced by a similar degree (29.3+/-3.6% and 32.0+/-3.3% of the region at risk, respectively; P<0.05 versus controls). The degree of protection could not be increased by doubling the dose of DETA/NO (group VIII, n=5). Coadministration of MPG completely abrogated the infarct-sparing action of DETA/NO (group X, n=7). Taken together, these results demonstrate that in conscious rabbits the administration of 2 structurally unrelated NO donors induces protection 24 hours later against both reversible (stunning) and irreversible (infarction) ischemia/reperfusion injury and that the magnitude of this protection is indistinguishable from that observed during the late phase of ischemic PC. The fact that the late phase of ischemic PC can be mimicked by NO donors provides direct evidence that NO in itself is sufficient to elicit this cardioprotective mechanism. The fact that NO donor-induced late PC was abrogated by MPG indicates that the mechanism whereby NO induces this phenomenon involves the generation of oxidant species, possibly ONOO- and/or .OH. Since a relatively brief treatment with hemodynamically inactive doses of NO donors can induce long-lasting protective effects, these agents could be useful for preconditioning the heart in patients.
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PMID:Nitric oxide donors induce late preconditioning against myocardial stunning and infarction in conscious rabbits via an antioxidant-sensitive mechanism. 967 Sep 20

Betahistine was administered during 4 weeks to 31 patients with vertigo, divided into 3 groups depending on changes in neurological examination. 1 group--13 patients without abnormalities, 2 group--11 with ischemia vertebrobasilaris, 3 group--7 with lesion of VIII nerves. Significant improvement was obtained in 20 patients (65%), most evident in group 1 (in 11). BAEP examination revealed abnormalities in 12 cases before the treatment and recovery in 4 (33.3%) after 4 weeks of treatment. They were: longer latency of the 1 component (39%), and III and V components mainly in the group with baso-vertebral ischemia. It confirms the supposition that disturbances of microcirculation are responsible for the mechanism of vertigo in these cases.
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PMID:[Treatment of vertigo with betahistine and its clinical and electrophysiological evaluation]. 1039 25

In situ split-liver transplantation is a new surgical technique where the bipartition of a single liver allows procurement of a right graft (segments I, IV, V-VIII) for an adult recipient (75% of the total liver volume), and a left graft (segments II and III) for a child recipient. The present study was designed to assess the effects of ischemia-reperfusion on right grafts obtained by in situ split-liver transplantation. To this aim, hepatic glutathione and conventional plasmatic markers of allograft function (alanine and aspartate aminotransferase, total bilirubin, prothrombin time, lactate dehydrogenase, gamma-glutamyltranspeptidase, and alkaline phosphatase) were evaluated in four adult recipients. At the time of reperfusion, a marked glutathione decrease was found in the segment VI in three cases, whereas the amount of glutathione in segment IV was related to the duration of cold ischemia in all cases. Upon reperfusion, a marked increase in plasmatic alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase was found. A recovery in prothrombin time was observed from the first day in three cases. An increasing trend in total bilirubin, gamma-glutamyltranspeptidase, and alkaline phosphatase was noted from the second day after transplant. This preliminary study suggests a possible relationship between the duration of cold ischemia, amount of glutathione in segment IV of the right graft, and the trend in plasmatic markers of allograft damage during in situ split-liver transplantation in adult recipients.
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PMID:Effects of ischemia-reperfusion on hepatic glutathione and plasmatic markers of graft function during in situ split-liver transplantation in adult recipients. 1111 71

Aging alters cardiac physiology and structure and enhances damage during ischemia and reperfusion. Aging selectively decreases the rate of oxidative phosphorylation in the interfibrillar population of cardiac mitochondria (IFM) located among the myofibers, whereas subsarcolemmal mitochondria (SSM) located beneath the plasma membrane remain unaffected. Aging decreased the rate of oxidative phosphorylation using durohydroquinone, an electron donor to complex III, in IFM only. Complex III activity was decreased in IFM, but not SSM. Aging did not alter the content of catalytic centers of complex III (cytochromes b and c(1)and iron-sulfur protein). Complex III activity measured at physiologic ionic strength in IFM from aging hearts was decreased by 49% compared to IFM from adults, whereas activity measured at low ionic strength was unchanged, localizing the aging defect to the cytochrome c binding site of complex III. Subunits VIII and X of the cytochrome c binding site were present in complex III with the aging defect, indicating that loss of subunits did not occur. Study of aging damage to complex III will help clarify the contribution of altered electron transport in IFM to increased oxidant production during aging, formation of the aging cardiac phenotype, and the relationship of aging defects to increased damage following ischemia.
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PMID:Aging decreases electron transport complex III activity in heart interfibrillar mitochondria by alteration of the cytochrome c binding site. 1113 21

Previously, PAHX-AP1 (PAHX-associated protein 1) was isolated as a novel protein to interact with Refsum disease gene product (phytanoyl-CoA alpha-hydroxylase, PAHX) and specifically expressed in mouse brain. PAHX-AP1 is also suggested to be involved in the development of the central neurologic deficits of Refsum disease. To clarify its function, we have searched for proteins that associate with PAHX-AP1 via yeast two-hybrid system. We found that PAHX-AP1 interacts with the cytoplasmic region of human brain-specific angiogenesis inhibitor 1 (hBAI1), and isolated murine homolog of hBAI1. Structural analysis of the PAHX-AP1 with three reported hBAI-associated proteins (BAP) revealed no homology among them, and we designated PAHX-AP1 as BAP4. The ability of BAP4 to interact with BAI1 was confirmed by pulling-down BAI1 with GST-BAP4 protein and immunoprecipitation study using brain lysate. Northern and Western blot analyses demonstrated a unique pattern of BAI1 expression in the brain. The peak level of BAI1 was observed 10 days after birth. In situ hybridization analyses of the brain showed the same localization of BAI1 as BAP4, such as most neurons of cerebral cortex, hippocampus, and V, VI, VII, VIII, and XII nuclei. Because BAI1 possessed thrombospondin-type 1 repeats in its extracellular region, changes of BAI1 expression were examined in the focal cerebral ischemia model. The BAI1 expression decreased on the ischemic side after 24 h but BAP4 was not changed after the time-course of ischemia. Our results indicate that expression and localization of BAI1 in the brain is correlated with BAP4, and that BAI1 is involved in inhibition of angiogenesis and neuronal differentiation.
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PMID:Characterization of mouse brain-specific angiogenesis inhibitor 1 (BAI1) and phytanoyl-CoA alpha-hydroxylase-associated protein 1, a novel BAI1-binding protein. 1124 25

In situ liver splitting provides a way to expand the graft pool, minimize cold ischemia time, and improve hemostasis at the cut surface of the graft. Vascular anomalies of the liver may make the splitting procedure very difficult or even impossible to perform. The in situ splitting procedure, performed on a liver with a middle hepatic vein (MHV) anomaly, is described here. The MHV drained directly into the segment III vein within the hepatic parenchyma instead of draining into the left hepatic vein to form the common trunk. In situ splitting was performed during multiorgan procurement from a 33-year-old man who died of isolated cerebral trauma. The MHV was reconstructed on the back table to secure right graft venous drainage using an iliac vein graft. The resultant right graft, segments I and IV to VIII, and left graft, segments II and III, were transplanted successfully into an adult and a child, respectively. The 2 transplant recipients are currently alive with normal hepatic function 20 months after transplantation.
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PMID:In situ splitting of a liver with middle hepatic vein anomaly. 1155 20

The case presented is that of a 29-year-old man with a history of hemophilia A who was admitted with recurrent onsets of transient cerebrovascular ischemia; he had undergone a transvenous closure of an atrial septal defects with an occluder device (Cardioseal Starflex) two months ago. Due to a factor-VIII deficiency, no further anticoagulation therapy was initiated. On admission, transesophageal echocardiography revealed a floating thrombus on the left atrial side of the umbrella. The device was explanted via a right minithoracotomy, and the atrial septal defect was closed. The patient had an uneventful recovery.
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PMID:Floating thrombus on an ASD occluder device in a patient with hemophilia A. 1160 46

The delta(2)- 1,2,3- triazoline anticonvulsants (TRs) may be considered as representing a unique class of "built-in" heterocyclic prodrugs where the active "structure element" is an integral part of the ring system and can be identified only by a knowledge of their chemical reactivity and metabolism. Investigations on the metabolism and pharmacology of a lead triazoline, ADD17014 suggest that the triazolines function as "prodrugs" and exert their anticonvulsant activity by impairing excitatory amino acid (EAA) L-Glutamate (L-Glu) neurotransmission via a unique "dual-action" mechanism. While an active primary beta-amino alcohol metabolite from the parent prodrug acts as an N-methyl-D-aspartate (NMDA)/MK -801 receptor antagonist, the parent triazoline impairs the presynaptic release of L-Glu. Various pieces of theoretical reasoning and experimental evidence have led to the clucidation of the dual-action mechanism. Based on the unique chemistry of the triazolines, and their metabolic pathways, biotransformation products of TRs were predicted to be the beta-amino alcohols V and VA, the alpha-amino acid VI, the triazole VII, the aziridine VIII and the ketimine IX. In vivo and in vitro pharmacological studies of the TR and potential metabolites, along with a full quantitative urinary metabolic profiling of TR indicated the primary beta-amino alcohol V as the active species. It was the only compound that inhibited the specific binding of [3H]MK-801 to the MK-801 site, 56% at 10 micro M drug concentration, but itself had no anticonvulsant activity, suggesting TR acted as a prodrug. Three metabolites were identified; V was the most predominant (45.7 +/- 7.6) % of administered drug, with lesser amounts of VA, (17.3 +/- 5.1) % and very minor amounts of aziridine VIII (4.0 +/- 0.02)%. Since only VIII can yield VA, its formation indicated that the biotransformation of TR occurred, at least in part, through aziridine. No amino acid metabolite was detected, which implied that no in vivo oxidation of V or oxidative biotransformation of TR or aziridine by hydroxylation at the methylene group occurred. While triazoline significantly decreased Ca(2+) -dependent, k(+)-evoked L-Glu release (83% at 100 micro M drug concentration ), some triazolines showed an augmentation of 50-63%, in the Cl(-) channel activity, a useful membrane action that reduces the excessive L-Glu release that occurs during epileptic seizures. The high anticonvulsant activity of TRs in a variety of seizure models including their effectiveness in the kindling model of complex partial seizures may be due to their unique dual-action mechanism whereby the TR and V together effectively impair both pre- and postsynaptic aspects of EAA neurotransmission; thus the TRs have clinical potential in the treatment of complex partial epilepsy which is refractory to currently available drugs. Since there is strong evidence that L-Glu plays an important role in human epilepsy as well as in brain ischemia/stroke, and since the TRs act by inhibiting EAA neurotransmission, it was logical to expect that the anticonvulsant TRs may evince beneficial therapeutic potential in cerebral ischemia resulting from stroke as well. And indeed, several TRs, when tested in the standard gerbil model of global ischemia did evince remarkable ability to prevent neuronal death.
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PMID:Rational drug design and the discovery of the delta2-1,2,3-triazolines, a unique class of anticonvulsant and antiischemic agents. 1287 Oct 87

Activated protein C (APC), a natural anticoagulant, is formed from protein C by the action of thrombin bound to thrombomodulin on the endothelial cell surface. APC regulates the coagulation system by inactivating the activated form of factors V and VIII in the presence of protein S. Tumor necrosis factor-alpha (TNF-alpha) plays critical roles in the development of disseminated intravascular coagulation, acute respiratory distress syndrome and shock in sepsis by inducing endothelial cell damage through activation of neutrophils. APC reduces the pulmonary endothelial cell injury and hypotension in rats administered endotoxin (ET) by inhibiting TNF-alpha production through inhibition of its transcription. Furthermore, APC reduces the ischemia/reperfusion-induced renal injury and the stress-induced gastric mucosal injury in rats. Inhibition by APC of the endothelial cell damage inhibited the decrease in the endothelial production of prostacyclin in vivo. These therapeutic effects could not be attributed to its anticoagulant effects, but to inhibition of TNF-alpha production. APC inhibits ET-induced TNF-alpha production in vitro in human monocytes by inhibiting activation of NFkappaB and AP-1 by inhibiting degradation of IkappaB and mitogen-activated protein kinase pathways, respectively. Recombinant APC was reported to reduce the mortality of patients with severe sepsis. These observations strongly suggest that APC might be involved not only in regulation of the coagulation system, but in regulation of inflammatory responses by preventing endothelial cell injury. Furthermore, APC reduced the spinal cord injury induced by compression-trauma or ischemia/reperfusion by inhibiting TNF-alpha production in rats, suggesting that APC may be a potential therapeutic agent for spinal cord injury in which only limited therapeutic measures are currently available.
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PMID:Prevention of endothelial cell injury by activated protein C: the molecular mechanism(s) and therapeutic implications. 1532 May 13

Paraplegia is a catastrophic complication of thoracic aortic surgery. At present, there is no effective mean to prevent the ischemia-induced spinal cord trauma. Gene delivery of neurotrophic factors may hold promises for prevention of spinal injury. In the present study, we evaluated the effect of glial cell line-derived neurotrophic factor (GDNF) gene delivery on prevention of the pathological changes due to spinal ischemia. Recombinant adenovirus vectors encoding GDNF (Ad-GDNF) and green fluorescent protein (Ad-GFP) were used for gene transfer studies. Treatment with cobalt chloride induced dose-dependent bcl-2 and synaptophysin downregulation in spinal neuronal cells, which could be effectively reversed by GDNF gene transfer. Intrathecal injection of Ad-GDNF led to maximal GDNF expression in spinal cord within 2-7 days. Thus, after intrathecal administration of adenovirus vectors for 3 days, Sprague-Dawley rats received transient aortic occlusion to induce spinal ischemia and were monitored for behavior deficits. The Ad-GDNF-treated rats showed significantly lower paraplegia rate (40%) than that of Ad-GFP- or saline-treated groups (75-85%; P<0.01). In addition, the Ad-GDNF-treated rats exhibited significantly improved locomotor function comparing with rats of control groups (P<0.001). Histological analysis revealed that GDNF gene delivery profoundly attenuated the infiltration of leukocytes in spinal cord after ischemic insults. Furthermore, GDNF gene delivery prominently attenuated the ischemia-induced neuronal loss in dorsal horn lamina VI-VIII and reduction in synaptophysin expression in spinal cords. In conclusion, GDNF gene transfer confers protection to the neuronal cells and synapses networks, thereby alleviated the paraplegia due to spinal ischemia.
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PMID:Intrathecal gene delivery of glial cell line-derived neurotrophic factor ameliorated paraplegia in rats after spinal ischemia. 1571 Feb 36


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