Sample records for ischemic preconditioning ip

  1. Tandem action of exercise training and food restriction completely preserves ischemic preconditioning in the aging heart

    Microsoft Academic Search

    P. Abete; G. Testa; G. Galizia; F. Mazzella; D. Della Morte; D. de Santis; C. Calabrese; F. Cacciatore; G. Gargiulo; N. Ferrara; G. Rengo; V. Sica; C. Napoli; F. Rengo

    2005-01-01

    Ischemic preconditioning (IP) has been proposed as an endogenous form of protection against ischemia reperfusion injury. IP, however, does not prevent post-ischemic dysfunction in the aging heart but may be partially corrected by exercise training and food restriction. We investigated the role of exercise training combined with food restriction on restoring IP in the aging heart. Effects of IP against

  2. Ischemic preconditioning protects cardiomyocyte mitochondria through mechanisms independent of cytosol.

    PubMed

    Ruiz-Meana, Marisol; Núñez, Estefanía; Miro-Casas, Elisabet; Martínez-Acedo, Pablo; Barba, Ignasi; Rodriguez-Sinovas, Antonio; Inserte, Javier; Fernandez-Sanz, Celia; Hernando, Victor; Vázquez, Jesús; Garcia-Dorado, David

    2014-03-01

    Mitochondria play a central role in the protection conferred by ischemic preconditioning (IP) by not fully elucidated mechanisms. We investigated whether IP protects mitochondria against ischemia-reperfusion (IR) injury through mechanisms independent of cytosolic signaling. In isolated rat hearts, sublethal IR increased superoxide production and reduced complex-I- and II-mediated respiration in subsarcolemmal (SS), but not interfibrillar (IF) mitochondria. This effect of IR on mitochondrial respiration was significantly attenuated by IP. Similar results were obtained in isolated cardiac mitochondria subjected to in vitro IR. The reduction in SS mitochondrial respiration in the heart and in vitro model was paralleled by an increase in oxidized cysteine residues, which was also prevented by IP. IP was also protective in mitochondria submitted to lethal IR. The protective effect of IP against respiratory failure was unaffected by inhibition of mitochondrial KATP channels or mitochondrial permeability transition. However, IP protection was lost in mitochondria from genetically-modified animals in which connexin-43, a protein present in SS but not IF mitochondria, was replaced by connexin-32. Our results demonstrate the existence of a protective mitochondrial mechanism or "mitochondrial preconditioning" independent of cytosol that confers protection against IR-induced respiratory failure and oxidative damage, and requires connexin-43. PMID:24434643

  3. Left ventricular dysfunction and disturbed O 2utilization in stunned myocardium: influence of ischemic preconditioning

    Microsoft Academic Search

    Ulrich Sunderdiek; Simone Schmitz-Spanke; Bernhard Korbmacher; Emmeran Gams; Jochen D Schipke

    2001-01-01

    Objective: Myocardial dysfunction during postischemic reperfusion is frequently reported only in terms of left ventricular (LV) systolic properties. We additionally assessed diastolic properties, the cardiovascular tone and in particular, the relation between ventricular function and myocardial oxygen consumption. Moreover, these measures are investigated after cardioprotection via ischemic preconditioning (IP). However, this phenomenon is not fully understood, and therefore cardioprotective methods

  4. ISCHEMIC PRECONDITIONING PREVENTS PROTEIN AGGREGATION AFTER TRANSIENT CEREBRAL ISCHEMIA

    PubMed Central

    Liu, C.; Chen, S.; Kamme, F.; Hu, B.R.

    2012-01-01

    Transient cerebral ischemia leads to protein aggregation mainly in neurons destined to undergo delayed neuronal death after ischemia. This study utilized a rat transient cerebral ischemia model to investigate whether ischemic preconditioning is able to alleviate neuronal protein aggregation, thereby protecting neurons from ischemic neuronal damage. Ischemic preconditioning was introduced by a sublethal 3 min period of ischemia followed by 48 h of recovery. Brains from rats with either ischemic preconditioning or sham-surgery were then subjected to a subsequent 7 min period of ischemia followed by 30 min, 4, 24, 48 and 72 h of reperfusion. Protein aggregation and neuronal death were studied by electron and confocal microscopy, as well as by biochemical analyses. Seven minutes of cerebral ischemia alone induced severe protein aggregation after 4 h of reperfusion mainly in CA1 neurons destined to undergo delayed neuronal death (which took place after 72 h of reperfusion). Ischemic preconditioning reduced significantly protein aggregation and virtually eliminated neuronal death in CA1 neurons. Biochemical analyses revealed that ischemic preconditioning decreased accumulation of ubiquitin-conjugated proteins (ubi-proteins) and reduced free ubiquitin depletion after brain ischemia. Furthermore, ischemic preconditioning also reduced redistribution of heat shock cognate protein 70 and Hdj1 from cytosolic fraction to protein aggregate-containing fraction after brain ischemia. These results suggest that ischemic preconditioning decreases protein aggregation after brain ischemia. PMID:15939539

  5. Limb ischemic preconditioning attenuates cerebral ischemic injury in rat model.

    PubMed

    Wang, W; Yu, X D; Mo, X; Zhang, H B; Zhu, D M

    2014-05-01

    Ischemic brain injury is not uncommon after open-heart surgery with cardiopulmonary bypass and seriously undermines the patients' life quality. Therefore, potential protective effects of limb ischemic preconditioning (LIP) on subsequent ischemic injury of the brain were investigated by evaluating anti-inflammatory effects and apoptosis of pyramidal neurons in the CA1 hippocampus. One hundred and eight Sprague-Dawley rats were divided into the middle cerebral artery occlusion (MCAO) group (n=54) and the LIP group (n=54). A thread was used to occlude the middle cerebral artery in the MCAO group and the LIP group animals were pretreated with LIP followed by MCAO. In the two groups, nine samples were collected at each time-point of 0, 6, 12, 24, 48 and 72 h after MCAO to detect IL-6 and IL-17 and their mRNA levels. Neurological severity scores (NSS) were examined before the animals were sacrificed. Compared with the LIP group, cerebral histopathological changes in the MCAO group were most distinct and significantly more infiltrated inflammatory and apoptotic neuronal cells were observed at 24, 48 and 72 h post-surgery. IL-17 and IL-6 mRNA levels analyzed by quantitative real-time polymerase chain reaction (PCR) (qRT-PCR) were significantly reduced in the LIP group compared with the MCAO group at the 12, 24 and 48 h time-points. A significant reduction in IL-17 expression level was determined by enzyme-linked immunosorbent assay (ELISA) in the LIP group at 12, 24 and 48 h, while IL-6 was significantly reduced at the 24 and 48 h time-points. The NSSs were not significantly different between the groups. Therefore, in a MCAO rat model, we have proved that LIP pretreatment can protect the brain from infarction after ischemic injury and induce ischemic tolerance, potentially, by reducing IL-17 to provide anti-inflammatory effects and attenuate apoptosis of hippocampal neuronal cells. PMID:24002779

  6. Pathways for ischemic cytoprotection: Role of sirtuins in caloric restriction, resveratrol, and ischemic preconditioning

    Microsoft Academic Search

    Kahlilia C Morris; Hung Wen Lin; John W Thompson; Miguel A Perez-Pinzon

    2011-01-01

    Caloric restriction (CR), resveratrol, and ischemic preconditioning (IPC) have been shown to promote protection against ischemic injury in the heart and brain, as well as in other tissues. The activity of sirtuins, which are enzymes that modulate diverse biologic processes, seems to be vital in the ability of these therapeutic modalities to prevent against cellular dysfunction and death. The protective

  7. Identification of a Novel Role for Sphingolipid Signaling in TNF ? and Ischemic Preconditioning Mediated Cardioprotection

    Microsoft Academic Search

    Sandrine Lecour; Robert M. Smith; Brian Woodward; Lionel H. Opie; Luc Rochette; Michael N. Sack

    2002-01-01

    TNF ? administration mimics ischemic preconditioning and neutralizing antibodies to TNF? and IL-1 ? abolish exercise-induced preconditioning. However, the pharmacology of TNF? 's cardioprotective effects and associated downstream signaling events has not been delineated. We evaluated the temporal and dose specific requirements of TNF ? to function as a preconditioning mimetic. Furthermore we postulated that the preconditioning effect of TNF

  8. Ischemic preconditioning enhances integrity of coronary endothelial tight junctions

    SciTech Connect

    Li, Zhao [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States)] [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States); Jin, Zhu-Qiu, E-mail: zhu-qiu.jin@sdstate.edu [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States)] [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States)

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Cardiac tight junctions are present between coronary endothelial cells. Black-Right-Pointing-Pointer Ischemic preconditioning preserves the structural and functional integrity of tight junctions. Black-Right-Pointing-Pointer Myocardial edema is prevented in hearts subjected to ischemic preconditioning. Black-Right-Pointing-Pointer Ischemic preconditioning enhances translocation of ZO-2 from cytosol to cytoskeleton. -- Abstract: Ischemic preconditioning (IPC) is one of the most effective procedures known to protect hearts against ischemia/reperfusion (IR) injury. Tight junction (TJ) barriers occur between coronary endothelial cells. TJs provide barrier function to maintain the homeostasis of the inner environment of tissues. However, the effect of IPC on the structure and function of cardiac TJs remains unknown. We tested the hypothesis that myocardial IR injury ruptures the structure of TJs and impairs endothelial permeability whereas IPC preserves the structural and functional integrity of TJs in the blood-heart barrier. Langendorff hearts from C57BL/6J mice were prepared and perfused with Krebs-Henseleit buffer. Cardiac function, creatine kinase release, and myocardial edema were measured. Cardiac TJ function was evaluated by measuring Evans blue-conjugated albumin (EBA) content in the extravascular compartment of hearts. Expression and translocation of zonula occludens (ZO)-2 in IR and IPC hearts were detected with Western blot. A subset of hearts was processed for the observation of ultra-structure of cardiac TJs with transmission electron microscopy. There were clear TJs between coronary endothelial cells of mouse hearts. IR caused the collapse of TJs whereas IPC sustained the structure of TJs. IR increased extravascular EBA content in the heart and myocardial edema but decreased the expression of ZO-2 in the cytoskeleton. IPC maintained the structure of TJs. Cardiac EBA content and edema were reduced in IPC hearts. IPC enhanced the translocation of ZO-2 from cytosol to cytoskeleton. In conclusion, TJs occur in normal mouse heart. IPC preserves the integrity of TJ structure and function that are vulnerable to IR injury.

  9. Remote Limb Ischemic Preconditioning: A Neuroprotective Technique in Rodents.

    PubMed

    Brandli, Alice

    2015-01-01

    Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. Sublethal ischemia has also been shown to upregulate protective mechanisms in remote tissues. A brief period of ischemia (5-10 min) in the hind limb of mammals induces self-protective responses in the brain, lung, heart and retina. The effect is known as remote ischemic preconditioning (RIP). It is a therapeutically promising way of protecting vital organs, and is already under clinical trials for heart and brain injuries. This publication demonstrates a controlled, minimally invasive method of making a limb - specifically the hind limb of a rat - ischemic. A blood pressure cuff developed for use in human neonates is connected to a manual sphygmomanometer and used to apply 160 mmHg pressure around the upper part of the hind limb. A probe designed to detect skin temperature is used to verify the ischemia, by recording the drop in skin temperature caused by pressure-induced occlusion of the leg arteries, and the rise in temperature which follows release of the cuff. This method of RIP affords protection to the rat retina against bright light-induced damage and degeneration. PMID:26065365

  10. Remote ischemic preconditioning delays fatigue development during handgrip exercise.

    PubMed

    Barbosa, T C; Machado, A C; Braz, I D; Fernandes, I A; Vianna, L C; Nobrega, A C L; Silva, B M

    2015-06-01

    Ischemic preconditioning (IPC) of one or two limbs improves performance of exercise that recruits the same limb(s). However, it is unclear whether IPC application to another limb than that in exercise is also effective and which mechanisms are involved. We investigated the effect of remote IPC (RIPC) on muscle fatigue, time to task failure, forearm hemodynamics, and deoxygenation during handgrip exercise. Thirteen men underwent RIPC in the lower limbs or a control intervention (CON), in random order, and then performed a constant load rhythmic handgrip protocol until task failure. Rates of contraction and relaxation (?Force/?Time) were used as indices of fatigue. Brachial artery blood flow and conductance, besides forearm microvascular deoxygenation, were assessed during exercise. RIPC attenuated the slowing of contraction and relaxation throughout exercise (P??0.05). In conclusion, RIPC applied to the lower limbs delayed the development of fatigue during handgrip exercise, prolonged time to task failure, but was not accompanied by changes in forearm hemodynamics and deoxygenation. PMID:24731023

  11. Neuroprotective effect of ischemic preconditioning in focal cerebral infarction: relationship with upregulation of vascular endothelial growth factor

    PubMed Central

    Liu, Yong; Zhu, Suiqiang; Wang, Yunfu; Hu, Jingquan; Xu, Lili; Ding, Li; Liu, Guangjian

    2014-01-01

    Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic preconditioning in rats by simulating a transient ischemic attack twice (each a 20-minute occlusion of the middle cerebral artery) before inducing focal cerebral infarction (2 hour occlusion-reperfusion in the same artery). We also explored the mechanism underlying the neuroprotective effect of ischemic preconditioning. Seven days after occlusion-reperfusion, tetrazolium chloride staining and immunohistochemistry revealed that the infarct volume was significantly smaller in the group that underwent preconditioning than in the model group. Furthermore, vascular endothelial growth factor immunoreactivity was considerably greater in the hippocampal CA3 region of preconditioned rats than model rats. Our results suggest that the protective effects of ischemic preconditioning on focal cerebral infarction are associated with upregulation of vascular endothelial growth factor. PMID:25206770

  12. Enhanced cell volume regulation: a key mechanism in local and remote ischemic preconditioning.

    PubMed

    Diaz, Roberto J; Harvey, Kordan; Boloorchi, Azadeh; Hossain, Taneya; Hinek, Alina; Backx, Peter H; Wilson, Gregory J

    2014-06-15

    We have previously shown that ischemic preconditioning (IPC) protection against necrosis in whole hearts and in both fresh and cultured cardiomyocytes, as well as the improved regulatory volume decrease to hypoosmotic swelling in cardiomyocytes, is abrogated through Cl(-) channel blockade, pointing to a role for enhanced cell volume regulation in IPC. To further define this cardioprotective mechanism, cultured rabbit ventricular cardiomyocytes were preconditioned either by 10-min simulated ischemia (SI) followed by 10-min simulated reperfusion (SR), by 10-min exposure/10-min washout of remote IPC (rIPC) plasma dialysate (from rabbits subjected to repetitive limb ischemia), or by adenoviral transfection with the constitutively active PKC-? gene. These interventions were done before cardiomyocytes were subjected to either 60- or 75-min SI/60-min SR to assess cell necrosis (by trypan blue staining), 30-min SI to assess ischemic cell swelling, or 30-min hypoosmotic (200 mosM) stress to assess cell volume regulation. Necrosis after SI/SR and both SI- and hypoosmotic stress-induced swelling was reduced in preconditioned cardiomyocytes compared with control cardiomyocytes (neither preconditioned nor transfected). These effects on necrosis and cell swelling were blocked by either Cl(-) channel blockade or dominant negative knockdown of inwardly rectifying K(+) channels with adenoviruses, suggesting that Cl(-) and K(+) movements across the sarcolemma are critical for cell volume regulation and, thereby, cell survival under hypoxic/ischemic conditions. Our results define enhanced cell volume regulation as a key common mechanism of cardioprotection by preconditioning in cardiomyocytes. PMID:24760980

  13. Hypoxia-inducible factor 1 is required for remote ischemic preconditioning of the heart.

    PubMed

    Cai, Zheqing; Luo, Weibo; Zhan, Huiwang; Semenza, Gregg L

    2013-10-22

    Both preclinical and clinical studies suggest that brief cycles of ischemia and reperfusion in the arm or leg may protect the heart against injury following prolonged coronary artery occlusion and reperfusion, a phenomenon known as remote ischemic preconditioning. Recent studies in mice indicate that increased plasma interleukin-10 (IL-10) levels play an important role in remote ischemic preconditioning induced by clamping the femoral artery for 5 min followed by 5 min of reperfusion for a total of three cycles. In this study, we demonstrate that remote ischemic preconditioning increases plasma IL-10 levels and decreases myocardial infarct size in wild-type mice but not in littermates that are heterozygous for a knockout allele at the locus encoding hypoxia-inducible factor (HIF) 1?. Injection of a recombinant adenovirus encoding a constitutively active form of HIF-1? into mouse hind limb muscle was sufficient to increase plasma IL-10 levels and decrease myocardial infarct size. Exposure of C2C12 mouse myocytes to cyclic hypoxia and reoxygenation rapidly increased levels of IL-10 mRNA, which was blocked by administration of the HIF-1 inhibitor acriflavine or by expression of short hairpin RNA targeting HIF-1? or HIF-1?. Chromatin immunoprecipitation assays demonstrated that binding of HIF-1 to the Il10 gene was induced when myocytes were subjected to cyclic hypoxia and reoxygenation. Taken together, these data indicate that HIF-1 activates Il10 gene transcription and is required for remote ischemic preconditioning. PMID:24101519

  14. Adeno-sh-?-Catenin Abolishes Ischemic Preconditioning–Mediated Cardioprotection by Downregulation of Its Target Genes VEGF, Bcl-2, and Survivin in Ischemic Rat Myocardium

    PubMed Central

    Thirunavukkarasu, Mahesh; Han, Zhihua; Zhan, Lijun; Penumathsa, Suresh Varma; Menon, Venugopal P.

    2008-01-01

    Abstract ?-Catenin, the downstream target of glycogen synthase kinase-3? (GSK-3?), plays a vital role in ischemic preconditioning (IP)-mediated cardioprotection. In the present study, we investigated the mechanism of IP-mediated cardioprotection through suppression of ?-catenin expression by intramyocardial injection of adeno-sh-RNA against ?-catenin (BCT) (4?×?108 pfu). Adeno-LacZ (LZ) was used as control. The rats were randomized into (a) LZ?+?ischemia–reperfusion (IR); (b) LZIPIR; (c) BCTIR; and (d) BCTIPIR. Isolated hearts from each group were subjected to 30?min of I followed by 2?h of R. Both IPIR group hearts were subjected to IP (5?min I?+?10?min R; four cycles) before IR. Significant reduction in left ventricular functional recovery (78 vs. 88?mm Hg), dp/dtmax (1,802 vs. 2,189?mm Hg/sec), and aortic flow (4 vs. 9?ml/min) was observed in BCTIPIR compared with LZIPIR at 120?min of reperfusion. Increased infarct size (42 vs. 24%) and apoptotic cardiomyocytes (122 vs. 58 counts/60 HPF) were observed in BCTIPIR compared with LZIPIR. Real-time PCR and Western blot analysis showed significant downregulation in mRNA and protein expression of VEGF, Bcl-2, and survivin in BCTIPIR compared with LZIPIR. These findings indicated for the first time that silencing ?-catenin abolished IP-mediated cardioprotection, probably through inhibition of VEGF-Bcl-2 and survivin. Antioxid. Redox Signal. 10, 1475–1485. PMID:18407748

  15. Alpha 1-adrenoceptor activation mediates the infarct size-limiting effect of ischemic preconditioning through augmentation of 5'-nucleotidase activity.

    PubMed Central

    Kitakaze, M; Hori, M; Morioka, T; Minamino, T; Takashima, S; Sato, H; Shinozaki, Y; Chujo, M; Mori, H; Inoue, M

    1994-01-01

    We have reported that ischemic preconditioning may limit infarct size by increasing 5'-nucleotidase activity. The present study tested whether alpha 1-adrenoceptor stimulation in ischemic preconditioning mediates the infarct size-limiting effect through augmentation of 5'-nucleotidase activity. The coronary artery was occluded four times for 5 min separated by 5 min of reperfusion (ischemic preconditioning) in 82 dogs. Then the coronary artery was occluded for 90 min followed by 6 h of reperfusion. Infarct size normalized by risk area was smaller after ischemic preconditioning than in the control group (40.6 +/- 2.3 vs 6.7 +/- 2.0%, P < 0.001), even though no difference existed in endomyocardial collateral flow during ischemia (8.7 +/- 1.0 vs 8.9 +/- 1.0 ml/100 g per min). Ectosolic and cytosolic 5'-nucleotidase activity was increased after ischemic preconditioning. However, prazosin blunted the infarct size-limiting effect of ischemic preconditioning (infarct size: 42.8 +/- 3.7%). Intermittent alpha 1-adrenoceptor stimulation by methoxamine mimicked the increase in 5'-nucleotidase activity and the infarct size-limiting effect, which were abolished by alpha, beta,-methyleneadenosine 5'-diphosphate. Identical results were obtained in the conscious model (n = 20). Therefore, we conclude that increases in ectosolic 5'-nucleotidase activity due to alpha 1-adrenoceptor activation may contribute to the infarct size-limiting effect of ischemic preconditioning. Images PMID:8182151

  16. Activation of Nrf2-Regulated Glutathione Pathway Genes by Ischemic Preconditioning

    PubMed Central

    Bell, Karen F. S.; Fowler, Jill H.; Al-Mubarak, Bashayer; Horsburgh, Karen; Hardingham, Giles E.

    2011-01-01

    Prophylactic pharmacological activation of astrocytic gene expression driven by the transcription factor Nrf2 boosts antioxidant defences and protects against neuronal loss in ischemia and other disease models. However, the role of Nrf2 in mediating endogenous neuroprotective responses is less clear. We recently showed that Nrf2 is activated by mild oxidative stress in both rodent and human astrocytes. Moreover, brief exposure to ischemic conditions was found to activate Nrf2 both in vivo and in vitro, and this was found to contribute to neuroprotective ischemic preconditioning. Here we show that transient ischemic conditions in vitro and in vivo cause an increase in the expression of Nrf2 target genes associated with the glutathione pathway, including those involved in glutathione biosynthesis and cystine uptake. Taken together, these studies indicate that astrocytic Nrf2 may represent an important mediator of endogenous neuroprotective preconditioning pathways. PMID:21904646

  17. The role of Tregs and CD11c(+) macrophages/dendritic cells in ischemic preconditioning of the kidney.

    PubMed

    Cho, Won Yong; Choi, Hye Min; Lee, So Young; Kim, Myung Gyu; Kim, Hyoung-Kyu; Jo, Sang-Kyung

    2010-11-01

    Dendritic cells have the potential to induce tolerance and here we attempted to identify their role in the tolerance seen in ischemic pre-conditioning. We induced bilateral renal ischemic preconditioning in mice and then challenged them with an ischemic insult 7 days later. Compared to sham-operated controls, preconditioned mice were found to have reduced injury with less inflammation, but had an increased number of regulatory T cells (Tregs) in their kidneys after the delayed insult. Splenocytes from these mice had more Tregs and mature CD11c(+) cells, but reduced proliferative and cytokine-secretory responses, suggesting a state of immunosuppression compared to control mice. Anti-CD25 depletion followed by adoptive transfer of Tregs partially mitigated and then restored the protective effect of preconditioning. Depletion of CD11c(+) cells with liposomes containing clodronate was associated with partial loss of preconditioning benefits. The increased numbers of Tregs or impaired immune response found in splenocytes from preconditioned mice were partially reversed in splenocytes from liposome clodronate-treated animals, suggesting that CD11c(+) cells contribute to immune cell-mediated ischemic preconditioning. Hence, our results show that ischemic preconditioning of the kidney provides a negative signal to the peripheral immune system, partially mediating the tissue-protective and anti-inflammatory effects of this maneuver. PMID:20686446

  18. Ischemic Preconditioning Targets the Respiration of Synaptic Mitochondria via Protein Kinase C?

    PubMed Central

    Dave, Kunjan R.; DeFazio, R. Anthony; Raval, Ami P.; Torraco, Alessandra; Saul, Isabel; Barrientos, Antoni; Perez-Pinzon, Miguel A.

    2008-01-01

    In the brain, ischemic preconditioning (IPC) diminishes mitochondrial dysfunction after ischemia and confers neuroprotection. Activation of ? protein kinase C (?PKC) has been proposed to be a key neuroprotective pathway during IPC. We tested the hypothesis that IPC increases the levels of ?PKC in synaptosomes from rat hippocampus, resulting in improved synaptic mitochondrial respiration. Preconditioning significantly increased the level of hippocampal synaptosomal ?PKC to 152% of sham-operated animals at 2 d of reperfusion, the time of peak neuroprotection. We tested the effect of ?PKC activation on hippocampal synaptic mitochondrial respiration 2 d after preconditioning. Treatment with the specific ?PKC activating peptide, tat-??RACK (tat-??-receptor for activated C kinase), increased the rate of oxygen consumption in the presence of substrates for complexes I, II, and IV to 157, 153, and 131% of control (tat peptide alone). In parallel, we found that ?PKC activation in synaptosomes from preconditioned animals resulted in altered levels of phosphorylated mitochondrial respiratory chain proteins: increased serine and tyrosine phosphorylation of 18 kDa subunit of complex I, decreased serine phosphorylation of FeS protein in complex III, increased threonine phosphorylation of COX IV (cytochrome oxidase IV), increased mitochondrial membrane potential, and decreased H2O2 production. In brief, ischemic preconditioning promoted significant increases in the level of synaptosomal ?PKC. Activation of ?PKC increased synaptosomal mitochondrial respiration and phosphorylation of mitochondrial respiratory chain proteins. We propose that, at 48 h of reperfusion after ischemic preconditioning, ?PKC is poised at synaptic mitochondria to respond to ischemia either by direct phosphorylation or activation of the ?PKC signaling pathway. PMID:18417696

  19. The role of remote ischemic preconditioning in the treatment of atherosclerotic diseases

    PubMed Central

    Vasdekis, Spyros N; Athanasiadis, Dimitrios; Lazaris, Andreas; Martikos, Georgios; Katsanos, Aristeidis H; Tsivgoulis, Georgios; Machairas, Anastasios; Liakakos, Theodoros

    2013-01-01

    Background Remote ischemic preconditioning (RIPC) is the application of a transient and brief ischemic stimulus to a distant site from the organ or tissue that is afterward exposed to injury ischemia, and has been found to reduce ischemia–reperfusion injury (IRI) in various animal models. RIPC appears to offer two distinct phases of endothelial IRI protection, which are presumably mediated through neuronal and humoral pathways. Methods We conducted a comprehensive literature review on the available published data about the potential effect of RIPC in patients undergoing IRI in one or more vital organs. Results Our search highlighted 24 randomized clinical trials about the effect of RIPC on variable clinical settings (abdominal aortic aneurysm repair, open heart surgery, percutaneous coronary intervention, living donor renal transplantation, coronary angiography, elective decompression surgery, carotid endarterectomy, recent stroke, or transient ischemic attack combined with intracranial carotid artery stenosis). Most of the trials focused on postoperative cardiac or renal function after RIPC with conflicting results. Preconditioning protocols, age limits, comorbidities, and concomitant drug use varied significantly across trials, and therefore no firm conclusions can be drawn using the available data. However, no severe local adverse events were observed in any patient undergoing limb or arm preconditioning. Conclusions RIPC is a safe and well-tolerated procedure that may constitute a potentially promising innovative treatment in atherosclerotic diseases. Large, multicenter, randomized clinical trials are required to determine an optimal protocol for the RIPC procedure, and to evaluate further the potential benefits of RIPC in human ischemic injury. PMID:24363964

  20. Novel Cellular Mechanisms for Neuroprotection in Ischemic Preconditioning: A View from Inside Organelles

    PubMed Central

    Sisalli, Maria Josè; Annunziato, Lucio; Scorziello, Antonella

    2015-01-01

    Ischemic preconditioning represents an important adaptation mechanism of CNS, which results in its increased tolerance to the lethal cerebral ischemia. The molecular mechanisms responsible for the induction and maintenance of ischemic tolerance in the brain are complex and not yet completely clarified. In the last 10?years, great attention has been devoted to unravel the intracellular pathways activated by preconditioning and responsible for the establishing of the tolerant phenotype. Indeed, recent papers have been published supporting the hypothesis that mitochondria might act as master regulators of preconditioning-triggered endogenous neuroprotection due to their ability to control cytosolic calcium homeostasis. More interestingly, the demonstration that functional alterations in the ability of mitochondria and endoplasmic reticulum (ER) managing calcium homeostasis during ischemia, opened a new line of research focused to the role played by mitochondria and ER cross-talk in the pathogenesis of cerebral ischemia in order to identify new molecular mechanisms involved in the ischemic tolerance. In line with these findings and considering that the expression of the three isoforms of the sodium calcium exchanger (NCX), NCX1, NCX2, and NCX3, mainly responsible for the regulation of Ca2+ homeostasis, was reduced during cerebral ischemia, it was investigated whether these proteins might play a role in neuroprotection induced by ischemic tolerance. In this review, evidence supporting the involvement of ER and mitochondria interaction within the preconditioning paradigm will be provided. In particular, the key role played by NCXs in the regulation of Ca2+-homeostasis at the different subcellular compartments will be discussed as new molecular mechanism proposed for the establishing of ischemic tolerant phenotype.

  1. Ischemic preconditioning ameliorates intestinal injury induced by ischemia-reperfusion in rats

    PubMed Central

    Ji, Yuan-Yuan; Wang, Zhi-Dong; Wang, Shu-Feng; Wang, Bao-Tai; Yang, Zheng-An; Zhou, Xiao-Rong; Lei, Ni-Na; Yue, Wei-Na

    2015-01-01

    AIM: To evaluate preventative effects of ischemic preconditioning (IP) in a rat model of intestinal injury induced by ischemia-reperfusion (IR). METHODS: Male Sprague-Dawley rats (250-300 g) were fasted for 24 h with free access to water prior to the operation. Eighteen rats were randomly divided into three experimental groups: S group (n = 6), rats were subjected to isolation of the superior mesenteric artery (SMA) for 40 min, then the abdomen was closed; IR group (n = 6), rats were subjected to clamping the SMA 40 min, and the abdomen was closed followed by a 4-h reperfusion; IP group (n = 6) rats underwent three cycles of 5 min ischemia and 5 min reperfusion, then clamping of the SMA for 40 min, then the abdomen was closed and a 4-h reperfusion followed. All animals were euthanized by barbiturate overdose (150 mg/kg pentobarbital sodium, i.v.) for tissue collection, and the SMA was isolated via median abdominal incision. Intestinal histologic injury was observed. Malondialdehyde (MDA), myeloperoxidase (MPO) and tumor necrosis factor (TNF)-? concentrations in intestinal tissue were measured. Intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 expression, as well as nuclear factor (NF)-?B activity and expression in intestinal tissue were also determined. RESULTS: Compared with the IR group, IP reduced IR-induced histologic injury of the intestine in rats (2.00 ± 0.71 vs 3.60 ± 0.84, P < 0.05). IP significantly inhibited the increase in MDA content (5.6 ± 0.15 ?mol/L vs 6.84 ± 0.18 ?mol/L, P < 0.01), MPO activity (0.13 ± 0.01 U/L vs 0.24 ± 0.01 U/L, P < 0.01), and TNF-? levels (7.79 ± 2.35 pg/mL vs 10.87 ± 2.48 pg/mL, P < 0.05) in the intestinal tissue of rats. IP also markedly ameliorated the increase in ICAM-1 (204.67 ± 53.27 vs 353.33 ± 45.19, P < 0.05) and VCAM-1 (256.67 ± 58.59 vs 377.33 ± 41.42, P < 0.05) protein expression in the intestinal tissues. Additionally, IP remarkably decreased NF-?B activity (0.48 ± 0.16 vs 0.76 ± 0.22, P < 0.05) and protein expression (320.23 ± 38.16 vs 520.76 ± 40.53, P < 0.01) in rat intestinal tissue. CONCLUSION: IP may protect against IR-induced intestinal injury by attenuation of the neutrophil-endothelial adhesion cascade via reducing ICAM-1 and VCAM-1 expression and TNF-?-induced NF-?B signaling pathway activity. PMID:26185379

  2. Ischemia-Induced Mitochondrial Apoptosis is Significantly Attenuated by Ischemic Preconditioning

    Microsoft Academic Search

    Peter Racay; Maria Chomova; Zuzana Tatarkova; Peter Kaplan; Jozef Hatok; Dusan Dobrota

    2009-01-01

    Ischemic preconditioning (IPC) represents an important adaptation of CNS to sub-lethal ischemia, which results in increased\\u000a tolerance of CNS to the lethal ischemia. Ischemia-induced mitochondrial apoptosis is considered to be an important event leading\\u000a to neuronal cell death after cerebral blood flow arrest. In presented study, we have determined the effect of IPC on ischemia\\/reperfusion-induced\\u000a mitochondrial apoptosis. Global brain ischemia

  3. Electroacupuncture preconditioning reduces cerebral ischemic injury via BDNF and SDF-1? in mice

    PubMed Central

    2013-01-01

    Background This study was designed to determine if electroacupuncture (EA) preconditioning improves tissue outcome and functional outcome following experimentally induced cerebral ischemia in mice. In addition, we investigated whether the expression of brain-derived neurotrophic factor (BDNF) and stromal cell derived factor-1? (SDF-1?) and infarct volume were related with improvement in neurological and motor function by interventions in this study. Methods After treatment with EA at the acupoints ‘Baihui (GV20)’ and ‘Dazhui (GV14)’ for 20 min, BDNF was assessed in the cortical tissues based on Western blot and the SDF-1? and vascular endothelial growth factor (VEGF) levels in the plasma determined by ELISA. To assess the protective effects of EA against ischemic injury, the mice received once a day 20 min EA preconditioning for three days prior to the ischemic event. Focal cerebral ischemia was then induced by photothrombotic cortical ischemia. Infarct volumes, neurobehavioral deficit and motor deficit were evaluated 24 h after focal cerebral ischemia. Results The expression of BDNF protein increased significantly from 6 h, reaching a plateau at 12 h after the end of EA treatment in the cerebral cortex. Furthermore, SDF-1?, not VEGF, increased singnificantly from 12 h to 48 h after EA stimulation in the plasma. Moreover, EA preconditioning reduced the infarct volume by 43.5% when compared to control mice at 24 h after photothrombotic cortical ischemia. Consistent with a smaller infarct size, EA preconditioning showed prominent improvement of neurological function and motor function such as vestibule-motor function, sensori-motor function and asymmetric forelimb use. The expression of BDNF colocalized within neurons and SDF-1? colocalized within the cerebral vascular endothelium was observed throughout the ischemic cortex by EA. Conclusions Pretreatment with EA increased the production of BDNF and SDF-1?, which elicited protective effects against focal cerebral ischemia. These results suggest a novel mechanism of EA pretreatment-induced tolerance against cerebral ischemic injury. PMID:23356671

  4. Remote ischemic preconditioning for myocardial protection: update on mechanisms and clinical relevance.

    PubMed

    Gill, Rabia; Kuriakose, Robin; Gertz, Zachary M; Salloum, Fadi N; Xi, Lei; Kukreja, Rakesh C

    2015-04-01

    Ischemic heart disease is the leading cause of death for both men and women worldwide, accruing 7.4 million deaths in 2012. There has been a continued search for better cardioprotective modalities that would reduce myocardial ischemia-reperfusion injury. Among these attempts, a more convenient model of ischemic preconditioning, known as remote ischemic preconditioning (RIPC) was first introduced in 1993 by Przyklenk and colleagues who reported that brief regional occlusion-reperfusion episodes in one vascular bed of the heart render protection to remote myocardial tissue. Subsequently, major advances in myocardial RIPC came with the use of skeletal muscle as the ischemic stimulus. To date, numerous studies have revealed that RIPC applied to the kidney, liver, mesentery, and skeletal muscle, have all exhibited cardioprotective effects. The main purpose of this review article is to summarize the new advances in understanding the molecular mechanisms of RIPC during the past 5 years, including those related to capsaicin-activated C sensory fibers, hypoxia-inducible factor 1?, connexin 43, extracellular vesicles, microRNA-144, microRNA-1, and nitrite. In addition, we have discussed results from several recent human clinical trials with RIPC. Taken together, the emerging clinical evidence supports the concept that the effectiveness of RIPC paired with its low-cost and non-invasive features makes it an ideal treatment before reperfusion after sustained ischemia. More carefully designed studies are warranted to fully exploit the clinical benefits of RIPC and its potential implications in patients with cardiovascular disease. PMID:25552250

  5. The Role of SUMO-Conjugating Enzyme Ubc9 in the Neuroprotection of Isoflurane Preconditioning Against Ischemic Neuronal Injury.

    PubMed

    Tong, Li; Wu, Zhixin; Ran, Mingzi; Chen, Yu; Yang, Lujia; Zhang, Haopeng; Zhang, Lina; Dong, Hailong; Xiong, Lize

    2015-06-01

    Preconditioning with volatile anesthetics can create an ischemia tolerance against cerebral ischemia-reperfusion injury. We investigated whether ubiquitin conjugase 9 (Ubc9), the E2 conjugase for SUMOylation, is associated with neuroprotection induced by isoflurane preconditioning (IsoPC). In vitro, Ubc9 protein expression was evaluated at 4 and 24 h after reoxygenation. The role of Ubc9 in the neuroprotective effect was assessed in the presence or absence of Ubc9 small interfering RNA (siRNA). In vivo, rats were preconditionally exposed for 1 h to 2 % isoflurane for five consecutive days followed by middle cerebral artery occlusion. Neurobehavioral scores and infarction volume were determined at different times after reperfusion. The role of Ubc9 in ischemic tolerance was evaluated by intracerebroventricular microinjection with the Ubc9 siRNA. We showed that isoflurane preconditioning improved the cell viability of the SH-SY5Y cells that were challenged by oxygen-glucose deprivation. It also reduced brain infarct volumes and improved neurologic outcomes in the focal cerebral ischemic rat. The expression of Ubc9 was upregulated by isoflurane preconditioning. Knockdown of Ubc9 significantly attenuated the isoflurane preconditioning-induced neuroprotective effects. Isoflurane preconditioning-induced neuroprotection against ischemic injuries is mediated by Ubc9. These results suggest a novel mechanism for isoflurane preconditioning-induced tolerance to cerebral ischemia. PMID:24961570

  6. Heme Oxygenase 1 Is Associated with Ischemic Preconditioning-Induced Protection Against Brain Ischemia

    PubMed Central

    Zeynalov, Emil; Shah, Zahoor A.; Li, Rung-chi; Doré, Sylvain

    2009-01-01

    Ischemic preconditioning (IPC) protects brain against ischemic injury by activating specific mechanisms. Our goal was to determine if the inducible heme oxygenase 1 (HO1) is required for such protection. IPC before transient or permanent ischemia reduced cortical infarct volumes by 57.4% and 33.9%, respectively at 48 h in wildtype adult mice. Interestingly, IPC failed to protect the HO1 gene deleted mice against permanent ischemic brain injury. IPC also resulted in a significant increase in HO1 protein levels in the brain and correlated with reduced neurological deficits after permanent and transient brain ischemia. Our study demonstrates that neuroprotective effects of IPC are at least partially mediated via HO1. Elucidating the physiological/cellular role by which HO1 is protective against brain ischemia may aid the development of selective drugs to treat stroke and its associated neurological disorders. PMID:19465127

  7. Endoplasmic reticulum stress-dependent activation of ATF3 mediates the late phase of ischemic preconditioning.

    PubMed

    Brooks, Alan C; Guo, Yiru; Singh, Mahavir; McCracken, James; Xuan, Yu-Ting; Srivastava, Sanjay; Bolli, Roberto; Bhatnagar, Aruni

    2014-11-01

    Ischemic preconditioning (PC) is an adaptive response to transient myocardial ischemia that protects the heart from subsequent ischemia/reperfusion (I/R) injury. However, the mechanisms underlying its cardioprotective effects remain unclear. Myocardium of adult male C57/BL6 mice, preconditioned by 6 cycles of 4 minute coronary occlusion and reperfusion, showed nuclear translocation of ATF3 and ATF6 and PERK phosphorylation 30 min after PC. The abundance of ER proteins, ATF3 and ATF4 was increased 24h after PC; however, there was no evidence of IRE-1 activation in WT or ER-stress activated indicator (ERAI) mice expressing XBP-1-Venus fusion protein. PC-induced nuclear translocation of ATF3 was attenuated in transgenic mice with cardiac-restricted overexpression of inducible ATF6. Ischemic PC increased the abundance of inducible nitric oxide synthase, cyclooxygenase-2, heme oxygenase-1 and aldose reductase to levels similar between WT and ATF3-null hearts; however, the increase in IL-6 and ICAM-1 was exaggerated in ATF3-null hearts. Genetic deletion of ATF3 did not increase infarct size in non-preconditioned hearts but abolished the cardioprotective effects of PC. Larger infarct size in preconditioned ATF3-null hearts was associated with greater neutrophil infiltration in the myocardium, but no ATF3-dependent changes in the total or relative abundance of inflammatory monocytes were observed. Ischemic PC activates the unfolded protein response (UPR) and the activation of ATF3 by ER stress is essential for the cardioprotective effects of late PC. PMID:25151953

  8. Roles of collateral arterial flow and ischemic preconditioning in protection of acutely ischemic myocardium.

    PubMed

    Jennings, Robert B; Wagner, Galen S

    2014-01-01

    The extent and rate at which necrosis develops in experimental acute myocardial infarction in the dog heart is presented together with an analysis of the role played by protective mechanisms in myocyte death. Preconditioning with ischemia delays but does not prevent myocyte death. Arterial collateral flows exceeding 30% of control flow essentially prevent myocyte death, while lesser amounts of collateral flow delay myocyte death to a variable extent. Flows of <0.09mlmin(-1)g(-1) wet exert no protective effect. Cell death occurs as quickly as it does with zero flow. Electrocardiography provides a means of detection of the preconditioned state in the dog heart in that the amount of ST elevation observed during the preconditioning episode is reduced during subsequent episodes of ischemia. Also, marked depression of arterial collateral flow can be detected by an increase in the duration of the QRS segment. PMID:24952922

  9. Ischemic Preconditioning Protects against Spinal Cord Ischemia-Reperfusion Injury in Rabbits by Attenuating Blood Spinal Cord Barrier Disruption.

    PubMed

    Fang, Bo; Li, Xiao-Man; Sun, Xi-Jia; Bao, Na-Ren; Ren, Xiao-Yan; Lv, Huang-Wei; Ma, Hong

    2013-01-01

    Ischemic preconditioning has been reported to protect against spinal cord ischemia-reperfusion (I-R) injury, but the underlying mechanisms are not fully understood. To investigate this, Japanese white rabbits underwent I-R (30 min aortic occlusion followed by reperfusion), ischemic preconditioning (three cycles of 5 min aortic occlusion plus 5 min reperfusion) followed by I-R, or sham surgery. At 4 and 24 h following reperfusion, neurological function was assessed using Tarlov scores, blood spinal cord barrier permeability was measured by Evan's Blue extravasation, spinal cord edema was evaluated using the wet-dry method, and spinal cord expression of zonula occluden-1 (ZO-1), matrix metalloproteinase-9 (MMP-9), and tumor necrosis factor-? (TNF-?) were measured by Western blot and a real-time polymerase chain reaction. ZO-1 was also assessed using immunofluorescence. Spinal cord I-R injury reduced neurologic scores, and ischemic preconditioning treatment ameliorated this effect. Ischemic preconditioning inhibited I-R-induced increases in blood spinal cord barrier permeability and water content, increased ZO-1 mRNA and protein expression, and reduced MMP-9 and TNF-? mRNA and protein expression. These findings suggest that ischemic preconditioning attenuates the increase in blood spinal cord barrier permeability due to spinal cord I-R injury by preservation of tight junction protein ZO-1 and reducing MMP-9 and TNF-? expression. PMID:23685868

  10. Ischemic Preconditioning Protects against Spinal Cord Ischemia-Reperfusion Injury in Rabbits by Attenuating Blood Spinal Cord Barrier Disruption

    PubMed Central

    Fang, Bo; Li, Xiao-Man; Sun, Xi-Jia; Bao, Na-Ren; Ren, Xiao-Yan; Lv, Huang-Wei; Ma, Hong

    2013-01-01

    Ischemic preconditioning has been reported to protect against spinal cord ischemia-reperfusion (I-R) injury, but the underlying mechanisms are not fully understood. To investigate this, Japanese white rabbits underwent I-R (30 min aortic occlusion followed by reperfusion), ischemic preconditioning (three cycles of 5 min aortic occlusion plus 5 min reperfusion) followed by I-R, or sham surgery. At 4 and 24 h following reperfusion, neurological function was assessed using Tarlov scores, blood spinal cord barrier permeability was measured by Evan’s Blue extravasation, spinal cord edema was evaluated using the wet-dry method, and spinal cord expression of zonula occluden-1 (ZO-1), matrix metalloproteinase-9 (MMP-9), and tumor necrosis factor-? (TNF-?) were measured by Western blot and a real-time polymerase chain reaction. ZO-1 was also assessed using immunofluorescence. Spinal cord I-R injury reduced neurologic scores, and ischemic preconditioning treatment ameliorated this effect. Ischemic preconditioning inhibited I-R-induced increases in blood spinal cord barrier permeability and water content, increased ZO-1 mRNA and protein expression, and reduced MMP-9 and TNF-? mRNA and protein expression. These findings suggest that ischemic preconditioning attenuates the increase in blood spinal cord barrier permeability due to spinal cord I-R injury by preservation of tight junction protein ZO-1 and reducing MMP-9 and TNF-? expression. PMID:23685868

  11. Possible involvement of caveolin in attenuation of cardioprotective effect of ischemic preconditioning in diabetic rat heart

    PubMed Central

    2011-01-01

    Background Nitric oxide (NO) has been noted to produce ischemic preconditioning (IPC)-mediated cardioprotection. Caveolin is a negative regulator of NO, which inhibits endothelial nitric oxide synthase (eNOS) by making caveolin-eNOS complex. The expression of caveolin is increased during diabetes mellitus (DM). The present study was designed to investigate the involvement of caveolin in attenuation of the cardioprotective effect of IPC during DM in rat. Methods Experimental DM was induced by single dose of streptozotocin (50 mg/Kg, i.p,) and animals were used for experiments four weeks later. Isolated heart was mounted on Langendorff's apparatus, and was subjected to 30 min of global ischemia and 120 min of reperfusion. IPC was given by four cycles of 5 min of ischemia and 5 min of reperfusion with Kreb's-Henseleit solution (K-H). Extent of injury was measured in terms of infarct size by triphenyltetrazolium chloride (TTC) staining, and release of lactate dehydrogenase (LDH) and creatin kinase-MB (CK-MB) in coronary effluent. The cardiac release of NO was noted by measuring the level of nitrite in coronary effluent. Results IPC- induced cardioprotection and release of NO was significantly decreased in diabetic rat heart. Pre-treatment of diabetic rat with daidzein (DDZ) a caveolin inhibitor (0.2 mg/Kg/s.c), for one week, significantly increased the release of NO and restored the attenuated cardioprotective effect of IPC. Also perfusion of sodium nitrite (10 ?M/L), a precursor of NO, significantly restored the lost effect of IPC, similar to daidzein in diabetic rat. Administration of 5-hydroxy deaconate (5-HD), a mito KATP channel blocker, significantly abolished the observed IPC-induced cardioprotection in normal rat or daidzein and sodium nitrite perfused diabetic rat heart alone or in combination. Conclusions Thus, it is suggested that attenuation of the cardioprotection in diabetic heart may be due to decrease the IPC mediated release of NO in the diabetic myocardium, which may be due to up -regulation of caveolin and subsequently decreased activity of eNOS. PMID:21745415

  12. Remote ischemic preconditioning reduces myocardial injury after coronary artery bypass surgery with crystalloid cardioplegic arrest

    Microsoft Academic Search

    Matthias Thielmann; Eva Kottenberg; Kerstin Boengler; Christoph Raffelsieper; Markus Neuhaeuser; Jürgen Peters; Heinz Jakob; Gerd Heusch

    2010-01-01

    Remote ischemic preconditioning (RIPC) with transient upper limb ischemia reduces myocardial injury in patients undergoing\\u000a on-pump coronary artery bypass grafting (CABG) with cross-clamp fibrillation or blood cardioplegia for myocardial protection.\\u000a Whether or not such protection is still operative when standard crystalloid cardioplegic arrest is used is uncertain. Fifty-three\\u000a consecutive, non-diabetic patients with triple-vessel disease and 64 ± 12 years of age (mean ± SD), who

  13. miR-15b Suppression of Bcl-2 Contributes to Cerebral Ischemic Injury and is Reversed by Sevoflurane Preconditioning

    PubMed Central

    Shi, Hong; Sun, Bao-liang; Zhang, Jia; Lu, Shiduo; Zhang, Pengyue; Wang, Hailian; Yu, Qiong; Stetler, R Anne; Vosler, Peter S.; Chen, Jun; Gao, Yanqin

    2014-01-01

    Ischemic neuroprotection afforded by sevoflurane preconditioning has been previously demonstrated, yet the underlying mechanism is poorly understood and likely affects a wide range of cellular activities. Several individual microRNAs have been implicated in both the pathogenesis of cerebral ischemia and cellular survival, and are capable of affecting a range of target mRNA. Conceivably, sevoflurane preconditioning may lead to alterations in ischemia-induced microRNA expression that may subsequently exert neuroprotective effects. We first examined the microRNA expression profile following transient cerebral ischemia in rats and the impact of sevoflurane preconditioning. Microarray analysis revealed that 3 microRNAs were up-regulated (>2.0 fold) and 9 were down-regulated (< 0.5 fold) following middle cerebral artery occlusion (MCAO) compared to sham controls. In particular, miR-15b was expressed at significantly high levels after MCAO. Preconditioning with sevoflurane significantly attenuated the upregulation of miR-15b at 72h after reperfusion. Bcl-2, an anti-apoptotic gene involved in the pathogenesis of cerebral ischemia, has been identified as a direct target of miR-15b. Consistent with the observed downregulation of miR-15b in sevoflurane-preconditioned brain, post-ischemic Bcl-2 expression was significantly increased by sevoflurane preconditioning. We identified the 3’-UTR of Bcl-2 as the target for miR-15b. Molecular inhibition of miR-15b was capable of mimicking the neuroprotective effect of sevoflurane preconditioning, suggesting that the suppression of miR-15b due to sevoflurane contributes to its ischemic neuroprotection. Thus, sevoflurane preconditioning may exert its anti-apoptotic effects by reducing the elevated expression of miR-15b following ischemic injury, allowing its target proteins, including Bcl-2, to be translated and expressed at the protein level. PMID:23469855

  14. Evaluation of the effects of ischemic preconditioning on the hematological parameters of rats subjected to intestinal ischemia and reperfusion

    PubMed Central

    Tahir, Muhammad; Arshid, Samina; Heimbecker, Ana Maria C; Castro, Mariana S; de Souza Montero, Edna Frasson; Fontes, Belchor; Fontes, Wagner

    2015-01-01

    OBJECTIVES: Intestinal ischemia/reperfusion often leads to acute lung injury and multiple organ failure. Ischemic preconditioning is protective in nature and reduces tissue injuries in animal and human models. Although hematimetric parameters are widely used as diagnostic tools, there is no report of the influence of intestinal ischemia/reperfusion and ischemic preconditioning on such parameters. We evaluated the hematological changes during ischemia/reperfusion and preconditioning in rats. METHODS: Forty healthy rats were divided into four groups: control, laparotomy, intestinal ischemia/reperfusion and ischemic preconditioning. The intestinal ischemia/reperfusion group received 45 min of superior mesenteric artery occlusion, while the ischemic preconditioning group received 10 min of short ischemia and reperfusion before 45 min of prolonged occlusion. A cell counter was used to analyze blood obtained from rats before and after the surgical procedures and the hematological results were compared among the groups. RESULTS: The results showed significant differences in hematimetric parameters among the groups. The parameters that showed significant differences included lymphocyte, white blood cells and granulocyte counts; hematocrit; mean corpuscular hemoglobin concentration; red cell deviation width; platelet count; mean platelet volume; plateletcrit and platelet distribution width. CONCLUSION: The most remarkable parameters were those related to leukocytes and platelets. Some of the data, including the lymphocyte and granulocytes counts, suggest that ischemic preconditioning attenuates the effect of intestinal ischemia/reperfusion on circulating blood cells. Our work contributes to a better understanding of the hematological responses after intestinal ischemia/reperfusion and IPC, and the present findings may also be used as predictive values. PMID:25672431

  15. TARGETED DELETION OF INDUCIBLE HEAT SHOCK PROTEIN 70 ABROGATES THE LATE INFARCT-SPARING EFFECT OF MYOCARDIAL ISCHEMIC PRECONDITIONING

    EPA Science Inventory

    Abstract submitted for 82nd annual meeting of the American Association for Thoracic Surgery, May 4-8, 2002 in Washington D.C. Targeted Deletion of Inducible Heat Shock Protein 70 Abrogates the Late Infarct-Sparing Effect of Myocardial Ischemic Preconditioning Craig...

  16. ATP-sensitive potassium channels mediate the anti-ischemic properties of ischemic and pharmacologic preconditioning in rat random-pattern skin flap.

    PubMed

    Beheshtian, Azadeh; Demehri, Shadpour; Kiumehr, Saman; Salmasi, Amirali Hassanzadeh; Nezami, Behtash Ghazi; Ghazinezami, Behtash; Rahimpour, Sina; Amanpour, Saeed; Rabbani, Shahram; Mohagheghi, Mohammad Ali; Dehpour, Ahmad Reza

    2006-07-01

    Ischemic preconditioning (IPC) and pharmacologic preconditioning by morphine and adenosine may significantly decrease the amount of necrosis in rat random pattern skin flaps. We examined the role of ATP-sensitive potassium channels (K(ATP) channels) in mediating these protective phenomenon by using glibenclamide a nonspecific blocker of these channels. We also investigated whether administration of diazoxide an opener of the K(ATP) channels could mimic the same protective effect. Ninety male Sprague-Dawley rats were randomly divided into either control or treatment groups (n = 6 each). Bipedicled dorsal skin flaps (2 x 8 cm) were elevated at the midline. In pharmacologic preconditioning groups, 1 mL of morphine (5 mg/flap), adenosine (0.5 mg/flap), or different doses of diazoxide (0.5, 1, 5, and 15 mg/flap) were administered locally in the cranial half of the flap, respectively. One milliliter of saline was locally injected in the control group. In the IPC group, 1 hour after local saline injection the cranial pedicle was clamped for 20 minutes, and then 40 minutes' reperfusion was performed. In another experiment, 0.3 mg/kg of glibenclamide was injected intraperitoneally 30 minutes before local administration of saline or drug in ischemic or pharmacologic preconditioning groups. Regardless of the group, all flaps were cut at the cranial side 2 hours after elevation and were sutured back. Flap survival area was evaluated on the seventh postoperative day. IPC and pharmacologic preconditioning with morphine, adenosine, and diazoxide (in higher doses; 1, 5, and 15 mg/flap) improved survival area compared with the control group. Glibenclamide abolished their protective effect. K(ATP) channels may have a key role in anti-ischemic properties of IPC and pharmacologic preconditioning. PMID:16799317

  17. A Randomized Pilot Trial of Remote Ischemic Preconditioning in Heart Failure with Reduced Ejection Fraction

    PubMed Central

    McDonald, Michael A.; Braga, Juarez R.; Li, Jing; Manlhiot, Cedric; Ross, Heather J.; Redington, Andrew N.

    2014-01-01

    Background Remote ischemic preconditioning (RIPC) induced by transient limb ischemia confers multi-organ protection and improves exercise performance in the setting of tissue hypoxia. We aimed to evaluate the effect of RIPC on exercise capacity in heart failure patients. Methods We performed a randomized crossover trial of RIPC (4×5-minutes limb ischemia) compared to sham control in heart failure patients undergoing exercise testing. Patients were randomly allocated to either RIPC or sham prior to exercise, then crossed over and completed the alternate intervention with repeat testing. The primary outcome was peak VO2, RIPC versus sham. A mechanistic substudy was performed using dialysate from study patient blood samples obtained after sham and RIPC. This dialysate was used to test for a protective effect of RIPC in a mouse heart Langendorff model of infarction. Mouse heart infarct size with RIPC or sham dialysate exposure was also compared with historical control data. Results Twenty patients completed the study. RIPC was not associated with improvements in peak VO2 (15.6+/?4.2 vs 15.3+/?4.6 mL/kg/min; p?=?0.53, sham and RIPC, respectively). In our Langendorff sub-study, infarct size was similar between RIPC and sham dialysate groups from our study patients, but was smaller than expected compared to healthy controls (29.0%, 27.9% [sham, RIPC] vs 51.2% [controls]. We observed less preconditioning among the subgroup of patients with increased exercise performance following RIPC (p<0.04). Conclusion In this pilot study of RIPC in heart failure patients, RIPC was not associated with improvements in exercise capacity overall. However, the degree of effect of RIPC may be inversely related to the degree of baseline preconditioning. These data provide the basis for a larger randomized trial to test the potential benefits of RIPC in patients with heart failure. Trial Registration ClinicalTrials.gov +++++NCT01128790 PMID:25181050

  18. Delayed Tolerance With Repetitive Transient Focal Ischemic Preconditioning in the Mouse

    PubMed Central

    Zhang, Jian; Yang, Zeng-Jin; Klaus, Judith A.; Koehler, Raymond C.; Huang, Judy

    2008-01-01

    Background and Purpose Transient ischemic attacks have long been regarded as a risk factor for the incidence of stroke but may reduce the severity of stroke by inducing ischemic tolerance. The present objective was to develop an ischemic preconditioning (IPC) model of delayed tolerance in the mouse based on repetitive, transient middle cerebral artery occlusion (MCAO). Methods Mice anesthetized with halothane or isoflurane underwent IPC, which consisted of repetitive MCAO at 45-minute intervals by the intraluminal filament technique. A 90-minute test MCAO was performed 24 to 96 hours later. Results Using an IPC of 2 5-minute MCAO episodes, the reduction in infarct volume from the test MCAO was maximal with a 72-hour delay in striatum (70%) and cerebral cortex (64%) when halothane was used for surgical anesthesia. With isoflurane anesthesia, the reduction in infarct volume was less prominent in striatum (34%) and not significant in cortex (9%) despite similar levels of arterial pressure and decreases in cortical perfusion. Neuronal cell death was rare 6 days after this IPC stimulus alone with halothane or isoflurane. Increasing the severity of IPC to 3 5-minute bouts or 1 15-minute bout of MCAO in the presence of isoflurane anesthesia augmented the reduction in infarct volume in striatum and cortex, but it also augmented selective neuronal cell death in striatum after the IPC stimulus alone. Conclusions These data demonstrate that a repetitive focal IPC stimulus can be titrated to induce delayed tolerance in both striatum and cortex of the mouse without inducing neuronal death by itself. PMID:18239169

  19. Exploring the Human Plasma Proteome for Humoral Mediators of Remote Ischemic Preconditioning - A Word of Caution

    PubMed Central

    Helgeland, Erik; Breivik, Lars Ertesvåg; Vaudel, Marc; Svendsen, Øyvind Sverre; Garberg, Hilde; Nordrehaug, Jan Erik; Berven, Frode Steingrimsen; Jonassen, Anne Kristine

    2014-01-01

    Despite major advances in early revascularization techniques, cardiovascular diseases are still the leading cause of death worldwide, and myocardial infarctions contribute heavily to this. Over the past decades, it has become apparent that reperfusion of blood to a previously ischemic area of the heart causes damage in and of itself, and that this ischemia reperfusion induced injury can be reduced by up to 50% by mechanical manipulation of the blood flow to the heart. The recent discovery of remote ischemic preconditioning (RIPC) provides a non-invasive approach of inducing this cardioprotection at a distance. Finding its endogenous mediators and their operative mode is an important step toward increasing the ischemic tolerance. The release of humoral factor(s) upon RIPC was recently demonstrated and several candidate proteins were published as possible mediators of the cardioprotection. Before clinical applicability, these potential biomarkers and their efficiency must be validated, a task made challenging by the large heterogeneity in reported data and results. Here, in an attempt to reproduce and provide more experimental data on these mediators, we conducted an unbiased in-depth analysis of the human plasma proteome before and after RIPC. From the 68 protein markers reported in the literature, only 28 could be mapped to manually reviewed (Swiss-Prot) protein sequences. 23 of them were monitored in our untargeted experiment. However, their significant regulation could not be reproducibly estimated. In fact, among the 394 plasma proteins we accurately quantified, no significant regulation could be confidently and reproducibly assessed. This indicates that it is difficult to both monitor and reproduce published data from experiments exploring for RIPC induced plasma proteomic regulations, and suggests that further work should be directed towards small humoral factors. To simplify this task, we made our proteomic dataset available via ProteomeXchange, where scientists can mine for novel potential targets. PMID:25333471

  20. Effect of ischemic and pharmacological preconditioning of lower limb muscle tissue on tissue oxygenation measured by near-infrared spectroscopy – a pilot study

    PubMed Central

    2014-01-01

    Background Ischemic or volatile anesthetic preconditioning is defined as tissue protection from impending ischemic cell damage by repetitive short periods of tissue exposure to ischemia or volatile anesthetics. Objective of this study was to elucidate, if ischemic preconditioning and pharmacological preconditioning with sevoflurane have effects on muscle tissue oxygen saturation in patients undergoing surgical revascularization of the lower limb. Methods In this prospective randomized pilot study ischemic and pharmacological (sevoflurane) preconditioning was performed in 40 patients with lower limb arterial occlusive disease undergoing surgical revascularization. Sevoflurane preconditioning was performed in one group (N?=?20) by repetitive application of sevoflurane for six minutes interspersed by six minutes of washout. Thereafter, ischemic preconditioning was performed in all patients (N?=?40) by repetitive clamping of the femoral artery for six minutes interspersed by six minutes of reperfusion. The effect of both procedures on leg muscle tissue oxygen saturation (rSO2) was measured by near-infrared spectroscopy during both procedures and during surgery and reperfusion (INVOS® 5100C Oxymeter with Small Adult SomaSensor® SAFB-SM, Somanetics, Troy, Michigan, USA). Results Repetitive clamping and reperfusion of the femoral artery resulted in significant cyclic decrease and increase of muscle rSO2 (p?preconditioning with sevoflurane resulted in a faster and higher increase of rSO2 during postoperative reperfusion (Maximal 111% baseline?±?20 versus 103% baseline?±?14, p?=?0.008) consistent with an additional effect of pharmacological preconditioning on leg perfusion. Conclusions Ischemic preconditioning of lower limb muscle tissue and pharmacological preconditioning with sevoflurane have an effect on tissue oxygenation in patients with lower limb occlusive arterial disease. Trial registration The trial has been registrated at http://www.ClinicalTrial.gov, Trial Number: NCT02038062 at 14 January 2014. PMID:25132803

  1. Loss of cardioprotection with ischemic preconditioning in aging hearts: role of sirtuin 1?

    PubMed

    Adam, Tasneem; Sharp, Stephanie; Opie, Lionel H; Lecour, Sandrine

    2013-01-01

    The effectiveness of ischemic preconditioning (IPC) to protect the heart against ischemia/reperfusion injury (IRI) declines with age. The deacetylase protein sirtuin 1 (Sirt 1) confers myriad functions including longevity and cardioprotection against IRI. As such, Sirt 1 may be a potential candidate to explain the protective effect of IPC. We aim to explore the role of Sirt 1 in the loss of the cardioprotective effect of IPC with age. Isolated hearts from young (9 weeks) and older (12-18 months) Long-Evans rats were subjected to 30 minutes of global ischemia and 60 minutes of reperfusion. Preconditioning stimuli were applied with either 2 cycles of 5-minute ischemia/reperfusion or with the potent Sirt 1 agonist resveratrol (RSV, 10 µmol/L) for 15 minutes followed by a 10-minute washout before the sustained ischemia. Both IPC and RSV significantly enhanced the functional recovery of young hearts by 168% (P < .001 vs control) and 65% (P < .01 vs control), respectively, and concomitantly reduced the infarct size by 65% and 45%, but the effect was blunted in older hearts. Administration of the selective Sirt 1 inhibitor III to young hearts did not alter the protective effect of IPC. Following ischemia/reperfusion, higher Sirt 1 deacetylase activity was detected in older hearts compared to young hearts (0.48 ± 0.13 arbitrary units [AU] vs 0.17 ± 0.03 AU, P < .01) and IPC did not alter Sirt 1 deacetylase activity. In conclusion, although Sirt 1 deacetylase activity is increased with age during ischemia/reperfusion, our data suggest that the loss of the cardioprotective effect of IPC in older animals is likely to be independent of Sirt 1. PMID:22960148

  2. Limb Ischemic Preconditioning Protects Endothelium from Oxidative Stress by Enhancing Nrf2 Translocation and Upregulating Expression of Antioxidases

    PubMed Central

    Chen, Min; Zhang, Mingsheng; Zhang, Xuanping; Li, Jie; Wang, Yan; Fan, Yanying; Shi, Ruizan

    2015-01-01

    Remote ischemic preconditioning is often performed by limb ischemic preconditioning (LIPC), which has been demonstrated to be beneficial to various cells, including endothelial cells. The mechanisms underlying the protection have not been well clarified. The present study was designed to observe the effects of sera derived from rats after LIPC on human umbilical vein endothelial cells (HUVECs) injured by hydrogen peroxide (H2O2) -induced oxidative stress and explore the involvement of redox state in the protection. Incubation with 1 mM H2O2 for 2 h induced a significant reduction in HUVECs’ viability with increased production of malondialdehyde (MDA) and reactive oxygen species (ROS). Preincubation with early preconditioning serum (EPS) or delayed preconditioning serum (DPS) derived from rats subjected to LIPC alleviated these changes. Both EPS and DPS increased the nuclear translocation of transcription factor nuclear factor E2-related factor 2 (Nrf2) and the expression of antioxidases. The protective effects of EPS and DPS were blocked neither by MEK/ERK inhibitors U0126 nor by PI3K/Akt inhibitors LY294002. In conclusion, the present study provides the evidence that LIPC protects the HUVECs from H2O2-induced injury by, at least partially, enhancement of Nrf2 translocation and upregulation of antioxidases via signaling pathways independent of MEK/ERK and PI3K/Akt. PMID:26029932

  3. Preconditioning: myocardial function and energetics during coronary hypoperfusion and reperfusion

    Microsoft Academic Search

    Ulrich Sunderdiek; Simone Schmitz-Spanke; Bernhard Korbmacher; Emmeran Gams; Jochen D. Schipke

    2002-01-01

    Background. Ischemic preconditioning (IP) is gaining more acceptance as a protective method in beating heart surgery. Yet it remains controversial whether preconditioning can attenuate myocardial dysfunction during reperfusion after severe coronary hypoperfusion. We examined this issue and also the issue of whether this protection is mediated by adenosine A1 receptors.Methods. In isolated, blood-perfused rabbit hearts, the effects of IP (3

  4. Mitogen-activated Protein Kinase p38? and Retinal Ischemic Preconditioning

    PubMed Central

    Dreixler, John C.; Barone, Frank C.; Shaikh, Afzhal R.; Du, Eugenie; Roth, Steven

    2009-01-01

    In previous studies, inhibition of mitogen activated protein kinase (MAP) p38 significantly improved recovery and attenuated apoptosis after retinal ischemia in rats. Yet, ischemic preconditioning (IPC) attenuated the ischemia-induced increase in p38 expression. We hypothesized that p38 was required for induction of ischemic tolerance by IPC. We examined the mechanisms of involvement of p38 in IPC neuroprotection. IPC or ischemia was induced in rat retina in vivo. Recovery after ischemia performed 24 h after IPC was assessed functionally (electroretinography) and histologically at 7 days after ischemia in the presence or absence of inhibition of p38. We examined the role of p38? in the mimicking of IPC produced by opening mitochondrial KATP channels using diazoxide, or stimulation of p38 activation by anisomycin. The importance of adenosine receptors in p38 activation after IPC was assessed using specific blockers of adenosine A1 and A2a receptors. Interfering RNA (siRNA) or SB203580 were used to block p38?. Phosphorylated p38 levels were measured. Phosphorylated p38 protein increased with IPC. Interfering RNA (siRNA) to p38? prior to IPC, or inhibiting p38 activation with SB203580, with ischemia following 24 h later, significantly attenuated the neuroprotective effect of IPC. Anisomycin administered to increase p38 mimicked IPC, an effect blocked by SB203580. IPC mimicking with diazoxide, an opener of mitochondrial KATP channels, was diminished with p38? siRNA. Adenosine receptor blockade did not decrease the elevated levels of phosphorylated p38 after IPC. Specific inhibition of p38? suggests that this MAPK is involved in the protective effects of IPC, and that p38 is downstream of mitochondrial KATP channels, but not adenosine receptors, in this neuroprotection. PMID:19631642

  5. Increased BDNF protein expression after ischemic or PKC epsilon preconditioning promotes electrophysiologic changes that lead to neuroprotection.

    PubMed

    Neumann, Jake T; Thompson, John W; Raval, Ami P; Cohan, Charles H; Koronowski, Kevin B; Perez-Pinzon, Miguel A

    2015-01-01

    Ischemic preconditioning (IPC) via protein kinase C epsilon (PKC?) activation induces neuroprotection against lethal ischemia. Brain-derived neurotrophic factor (BDNF) is a pro-survival signaling molecule that modulates synaptic plasticity and neurogenesis. Interestingly, BDNF mRNA expression increases after IPC. In this study, we investigated whether IPC or pharmacological preconditioning (PKC? activation) promoted BDNF-induced neuroprotection, if neuroprotection by IPC or PKC? activation altered neuronal excitability, and whether these changes were BDNF-mediated. We used both in vitro (hippocampal organotypic cultures and cortical neuronal-glial cocultures) and in vivo (acute hippocampal slices 48 hours after preconditioning) models of IPC or PKC? activation. BDNF protein expression increased 24 to 48 hours after preconditioning, where inhibition of the BDNF Trk receptors abolished neuroprotection against oxygen and glucose deprivation (OGD) in vitro. In addition, there was a significant decrease in neuronal firing frequency and increase in threshold potential 48 hours after preconditioning in vivo, where this threshold modulation was dependent on BDNF activation of Trk receptors in excitatory cortical neurons. In addition, 48 hours after PKC? activation in vivo, the onset of anoxic depolarization during OGD was significantly delayed in hippocampal slices. Overall, these results suggest that after IPC or PKC? activation, there are BDNF-dependent electrophysiologic modifications that lead to neuroprotection. PMID:25370861

  6. Hyperglycemia abolishes the protective effect of ischemic preconditioning in glomerular endothelial cells in vitro

    PubMed Central

    Schenning, Katie J; Anderson, Sharon; Alkayed, Nabil J; Hutchens, Michael P

    2015-01-01

    In preclinical investigations, ischemic preconditioning (IPC) protects kidneys from ischemia/reperfusion injury. The direct effects of IPC on glomerular endothelial cells have not been studied in detail. Most investigations of IPC have focused on healthy cells and animals, and it remains unknown whether IPC is renoprotective in the setting of medical comorbidities such as diabetes. In this study, we determined the preventive potential of IPC in healthy glomerular endothelial cell monolayers, and compared these results to monolayers cultured under hyperglycemic conditions. We exposed glomerular endothelial monolayers to 1 h of IPC 24 h prior to oxygen–glucose deprivation (OGD), an in vitro model of ischemia/reperfusion injury. Glomerular endothelial monolayer integrity was assessed by measuring transendothelial electrical resistance, albumin flux, and cell survival. We found that IPC protected healthy but not hyperglycemic glomerular endothelial monolayers from ischemia/reperfusion injury. Furthermore, not only was the protective effect of IPC lost in the setting of hyperglycemia, but IPC was actually deleterious to the integrity of hyperglycemic glomerular endothelial cell monolayers. PMID:25804266

  7. Cardiac Phosphoproteomics during Remote Ischemic Preconditioning: A Role for the Sarcomeric Z-Disk Proteins

    PubMed Central

    Abdul-Ghani, Safa; Heesom, Kate J.; Angelini, Gianni D.; Suleiman, M-Saadeh

    2014-01-01

    Remote ischemic preconditioning (RIPC) induced by brief ischemia/reperfusion cycles of remote organ (e.g., limb) is cardioprotective. The myocardial cellular changes during RIPC responsible for this phenomenon are not currently known. The aim of this work was to identify the activation by phosphorylation of cardiac proteins following RIPC. To achieve our aim we used isobaric tandem mass tagging (TMT) and reverse phase nanoliquid chromatography tandem spectrometry using a Linear Trap Quadropole (LTQ) Orbitrap Velos mass spectrometer. Male C57/Bl6 mice were anesthetized by an intraperitoneal injection of Tribromoethanol. A cuff was placed around the hind limb and inflated at 200?mmHg to prevent blood flow as confirmed by Laser Doppler Flowmetry. RIPC was induced by 4 cycles of 5?min of limb ischemia followed by 5?min of reperfusion. Hearts were extracted for phosphoproteomics. We identified approximately 30 phosphoproteins that were differentially expressed in response to RIPC protocol. The levels of several phosphoproteins in the Z-disk of the sarcomere including phospho-myozenin-2 were significantly higher than control. This study describes and validates a novel approach to monitor the changes in the cardiac phosphoproteome following the cardioprotective intervention of RIPC and prior to index ischemia. The increased level of phosphorylated sarcomeric proteins suggests they may have a role in cardiac signaling during RIPC. PMID:24795895

  8. Cardiac phosphoproteomics during remote ischemic preconditioning: a role for the sarcomeric Z-disk proteins.

    PubMed

    Abdul-Ghani, Safa; Heesom, Kate J; Angelini, Gianni D; Suleiman, M-Saadeh

    2014-01-01

    Remote ischemic preconditioning (RIPC) induced by brief ischemia/reperfusion cycles of remote organ (e.g., limb) is cardioprotective. The myocardial cellular changes during RIPC responsible for this phenomenon are not currently known. The aim of this work was to identify the activation by phosphorylation of cardiac proteins following RIPC. To achieve our aim we used isobaric tandem mass tagging (TMT) and reverse phase nanoliquid chromatography tandem spectrometry using a Linear Trap Quadropole (LTQ) Orbitrap Velos mass spectrometer. Male C57/Bl6 mice were anesthetized by an intraperitoneal injection of Tribromoethanol. A cuff was placed around the hind limb and inflated at 200?mmHg to prevent blood flow as confirmed by Laser Doppler Flowmetry. RIPC was induced by 4 cycles of 5?min of limb ischemia followed by 5?min of reperfusion. Hearts were extracted for phosphoproteomics. We identified approximately 30 phosphoproteins that were differentially expressed in response to RIPC protocol. The levels of several phosphoproteins in the Z-disk of the sarcomere including phospho-myozenin-2 were significantly higher than control. This study describes and validates a novel approach to monitor the changes in the cardiac phosphoproteome following the cardioprotective intervention of RIPC and prior to index ischemia. The increased level of phosphorylated sarcomeric proteins suggests they may have a role in cardiac signaling during RIPC. PMID:24795895

  9. Long-term, regular remote ischemic preconditioning improves endothelial function in patients with coronary heart disease

    PubMed Central

    Liang, Y.; Li, Y.P.; He, F.; Liu, X.Q.; Zhang, J.Y.

    2015-01-01

    Remote ischemic preconditioning (RIPre) can prevent myocardial injury. The purpose of this study was to assess the beneficial effects of long-term regular RIPre on human arteries. Forty patients scheduled for coronary artery bypass graft (CABG) surgery were assigned randomly to a RIPre group (n=20) or coronary heart disease (CHD) group (n=20). Twenty patients scheduled for mastectomy were enrolled as a control group. RIPre was achieved by occluding arterial blood flow 5 min with a mercury sphygmomanometer followed by a 5-min reperfusion period, and this was repeated 4 times. The RIPre procedure was repeated 3 times a day for 20 days. In all patients, arterial fragments discarded during surgery were collected to evaluate endothelial function by flow-mediated dilation (FMD), CD34+ monocyte count, and endothelial nitric oxide synthase (eNOS expression). Phosphorylation levels of STAT-3 and Akt were also assayed to explore the underlying mechanisms. Compared with the CHD group, long-term regular RIPre significantly improved FMD after 20 days (8.5±2.4 vs 4.9±4.2%, P<0.05) and significantly reduced troponin after CABG surgery (0.72±0.31 and 1.64±0.19, P<0.05). RIPre activated STAT-3 and increased CD34+ endothelial progenitor cell counts found in arteries. Long-term, regular RIPre improved endothelial function in patients with CHD, possibly due to STAT-3 activation, and this may have led to an increase in endothelial progenitor cells. PMID:25923462

  10. Unique Transcriptional Profile of Sustained Ligand-Activated Preconditioning in Pre- and Post-Ischemic Myocardium

    PubMed Central

    Ashton, Kevin J.; Tupicoff, Amanda; Williams-Pritchard, Grant; Kiessling, Can J.; See Hoe, Louise E.; Headrick, John P.; Peart, Jason N.

    2013-01-01

    Background Opioidergic SLP (sustained ligand-activated preconditioning) induced by 3–5 days of opioid receptor (OR) agonism induces persistent protection against ischemia-reperfusion (I-R) injury in young and aged hearts, and is mechanistically distinct from conventional preconditioning responses. We thus applied unbiased gene-array interrogation to identify molecular effects of SLP in pre- and post-ischemic myocardium. Methodology/Principal Findings Male C57Bl/6 mice were implanted with 75 mg morphine or placebo pellets for 5 days. Resultant SLP did not modify cardiac function, and markedly reduced dysfunction and injury in perfused hearts subjected to 25 min ischemia/45 min reperfusion. Microarray analysis identified 14 up- and 86 down-regulated genes in normoxic hearts from SLP mice (?1.3-fold change, FDR?5%). Induced genes encoded sarcomeric/contractile proteins (Myh7, Mybpc3,Myom2,Des), natriuretic peptides (Nppa,Nppb) and stress-signaling elements (Csda,Ptgds). Highly repressed genes primarily encoded chemokines (Ccl2,Ccl4,Ccl7,Ccl9,Ccl13,Ccl3l3,Cxcl3), cytokines (Il1b,Il6,Tnf) and other proteins involved in inflammation/immunity (C3,Cd74,Cd83, Cd86,Hla-dbq1,Hla-drb1,Saa1,Selp,Serpina3), together with endoplasmic stress proteins (known: Dnajb1,Herpud1,Socs3; putative: Il6, Gadd45g,Rcan1) and transcriptional controllers (Egr2,Egr3, Fos,Hmox1,Nfkbid). Biological themes modified thus related to inflammation/immunity, together with cellular/cardiovascular movement and development. SLP also modified the transcriptional response to I-R (46 genes uniquely altered post-ischemia), which may influence later infarction/remodeling. This included up-regulated determinants of cellular resistance to oxidant (Mgst3,Gstm1,Gstm2) and other forms of stress (Xirp1,Ankrd1,Clu), and repression of stress-response genes (Hspa1a,Hspd1,Hsp90aa,Hsph1,Serpinh1) and Txnip. Conclusions Protection via SLP is associated with transcriptional repression of inflammation/immunity, up-regulation of sarcomeric elements and natriuretic peptides, and modulation of cell stress, growth and development, while conventional protective molecules are unaltered. PMID:23991079

  11. Remote ischemic preconditioning delays the onset of acute mountain sickness in normobaric hypoxia

    PubMed Central

    Berger, Marc M; Köhne, Hannah; Hotz, Lorenz; Hammer, Moritz; Schommer, Kai; Bärtsch, Peter; Mairbäurl, Heimo

    2015-01-01

    Acute mountain sickness (AMS) is a neurological disorder occurring when ascending too fast, too high. Remote ischemic preconditioning (RIPC) is a noninvasive intervention protecting remote organs from subsequent hypoxic damage. We hypothesized that RIPC protects against AMS and that this effect is related to reduced oxidative stress. Fourteen subjects were exposed to 18 hours of normoxia (21% oxygen) and 18 h of normobaric hypoxia (12% oxygen, equivalent to 4500 m) on different days in a blinded, randomized order. RIPC consisted of four cycles of lower limb ischemia (5 min) and 5 min of reperfusion, and was performed immediately before the study room was entered. A control group was exposed to hypoxia (12% oxygen, n = 14) without RIPC. AMS was evaluated by the Lake Louise score (LLS) and the AMS-C score of the Environmental Symptom Questionnaire. Plasma concentrations of ascorbate radicals, oxidized sulfhydryl (SH) groups, and electron paramagnetic resonance (EPR) signal intensity were measured as biomarkers of oxidative stress. RIPC reduced AMS scores (LLS: 1.9 ± 0.4 vs. 3.2 ± 0.5; AMS-C score: 0.4 ± 0.1 vs. 0.8 ± 0.2), ascorbate radicals (27 ± 7 vs. 65 ± 18 nmol/L), oxidized SH groups (3.9 ± 1.4 vs. 14.3 ± 4.6 ?mol/L), and EPR signal intensity (0.6 ± 0.2 vs. 1.5 ± 0.4 × 106) after 5 h in hypoxia (all P < 0.05). After 18 hours in hypoxia there was no difference in AMS and oxidative stress between RIPC and control. AMS and plasma markers of oxidative stress did not correlate. This study demonstrates that RIPC transiently reduces symptoms of AMS and that this effect is not associated with reduced plasma levels of reactive oxygen species. PMID:25742960

  12. Impact of ischemic preconditioning on functional sympatholysis during handgrip exercise in humans.

    PubMed

    Horiuchi, Masahiro; Endo, Junko; Thijssen, Dick H J

    2015-02-01

    Repeated bouts of ischemia followed by reperfusion, known as ischemic preconditioning (IPC), is found to improve exercise performance. As redistribution of blood from the inactive areas to active skeletal muscles during exercise (i.e., functional sympatholysis) is important for exercise performance, we examined the hypothesis that IPC improves functional sympatholysis in healthy, young humans. In a randomized study, 15 healthy young men performed a 10-min resting period, dynamic handgrip exercise at 10% maximal voluntary contraction (MVC), and 25% MVC. This protocol was preceded by IPC (IPC; 4 × 5-min 220-mmHg unilateral occlusion) or a sham intervention (CON; 4 × 5-min 20-mmHg unilateral occlusion). Near-infrared spectroscopy was used to assess changes in oxygenated hemoglobin and myoglobin in skeletal muscle (HbO2 + MbO2) in response to sympathetic activation (via cold pressor test (CPT)) at baseline and during handgrip exercise (at 10% and 25%). In resting conditions, HbO2 + MbO2 significantly decreased during CPT (-11.0 ± 1.0%), which was significantly larger during the IPC-trial (-13.8 ± 1.2%, P = 0.006). During handgrip exercise at 10% MVC, changes in HbO2 + MbO2 in response to the CPT were blunted after IPC (-8.8 ± 1.5%) and CON (-8.3 ± 0.4%, P = 0.593). During handgrip exercise at 25% MVC, HbO2 + MbO2 in response to the CPT increased (2.0 ± 0.4%), whereas this response was significantly larger when preceded by IPC (4.2 ± 0.6%, P = 0.027). Collectively, these results indicate that IPC-induced different vascular changes at rest and during moderate exercise in response to sympathetic activation. This suggests that, in healthy volunteers, exposure to IPC may alter tissue oxygenation during sympathetic stimulation at rest and during exercise. PMID:25713329

  13. Identical MicroRNAs Regulate Liver Protection during Anaesthetic and Ischemic Preconditioning in Rats: An animal study

    PubMed Central

    Morita, Tomonori; Ishikawa, Masashi; Sakamoto, Atsuhiro

    2015-01-01

    Anaesthetic preconditioning (APC) and ischemic preconditioning (IPC) ameliorate liver ischemia–reperfusion (I/R) injury and are important for regulating hepatic I/R injury. MicroRNAs (miRNAs) are short, noncoding RNA molecules of 21–23 nucleotides in length, and are currently under intensive investigation regarding their ability to regulate gene expression in a wide range of species. miRNA activity is involved in controlling a wide range of biological functions and processes. We evaluated whether APC and IPC are mediated by the same miRNAs by performing comprehensive miRNA screening experiments in a rat model of hepatic I/R injury. Twenty-one rats were randomly divided into three groups (n = 7/group): control (mock preconditioning), APC, and IPC. Control rats were subjected to 60 min of hepatic ischemia followed by 4 h of reperfusion, whereas the APC and IPC groups were preconditioned with 2% sevoflurane and hepatic ischemia for 10 min prior to ischemia-reperfusion, respectively. Liver samples were collected to measure miRNA levels after 3 h of reperfusion, and gene networks and canonical pathways were identified using Ingenuity Pathway Analysis (IPA). Blood samples were collected to measure the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Although haemodynamic parameters did not vary among the groups, AST and ALT levels were significantly higher in the control group than in the APC and IPC groups. Comprehensive miRNA screening experiments revealed that most miRNAs altered in the APC group were common to those in the IPC group. IPA identified five miRNAs related to the Akt–glycogen synthase kinase-3? (GSK-3?)–cyclin D1 pathway that were significantly affected by both preconditioning strategies. The application of either APC or IPC to ameliorate hepatic I/R injury results in expression of several common miRNAs that are related to the Akt–GSK–cyclin D1 pathway. PMID:25974021

  14. HSP70.1 AND -70.3 ARE REQUIRED FOR LATE-PHASE PROTECTION INDUCED BY ISCHEMIC PRECONDITIONING OF MOUSE HEARTS

    EPA Science Inventory

    Heat-Shock Proteins 70.1 and 70.3 Are Required for Late-phase Protection Induced by Ischemic Preconditioning of the Mouse Heart Craig R. Hampton 1 , Akira Shimamoto 1 , Christine L. Rothnie 1 , Jeaneatte Griscavage-Ennis 1 , Albert Chong 1 , David J. Dix 2 , Edward D. Ve...

  15. Bradykinin preconditioning modulates aquaporin-4 expression after spinal cord ischemic injury in rats

    Microsoft Academic Search

    Xu Wei-bing; Gu Yan-ting; Wang Yan-feng; Lu Xu-hua; Jia Lian-shun; Lv Gang

    2008-01-01

    The study investigated whether bradykinin (BK) preconditioning could regulate the expression of aquaporin-4 (AQP4) using an in vivo transient spinal cord ischemia model in rats. BK was infused continuously via the left femoral artery with infusion pump for 15 min (10 µg\\/kg\\/min) then we induced ischemia for 20 min and reperfusion for 24 and 72 h respectively. The results demonstrated that the central part

  16. Myocardial ischemic preconditioning upregulated protein 1(Mipu1):zinc finger protein 667 - a multifunctional KRAB/C2H2 zinc finger protein.

    PubMed

    Han, D; Zhang, C; Fan, W J; Pan, W J; Feng, D M; Qu, S L; Jiang, Z S

    2015-01-01

    Myocardial ischemic preconditioning upregulated protein 1 (Mipu1) is a newly discovered upregulated gene produced in rats during the myocardial ischemic preconditioning process. Mipu1 cDNA contains a 1824-base pair open reading frame and encodes a 608 amino acid protein with an N-terminal Krüppel-associated box (KRAB) domain and classical zinc finger C2H2 motifs in the C-terminus. Mipu1 protein is located in the cell nucleus. Recent studies found that Mipu1 has a protective effect on the ischemia-reperfusion injury of heart, brain, and other organs. As a nuclear factor, Mipu1 may perform its protective function through directly transcribing and repressing the expression of proapoptotic genes to repress cell apoptosis. In addition, Mipu1 also plays an important role in regulating the gene expression of downstream inflammatory mediators by inhibiting the activation of activator protein-1 and serum response element. PMID:25493376

  17. Myocardial ischemic preconditioning upregulated protein 1(Mipu1):zinc finger protein 667 - a multifunctional KRAB/C2H2 zinc finger protein.

    PubMed

    Han, D; Zhang, C; Fan, W J; Pan, W J; Feng, D M; Qu, S L; Jiang, Z S

    2014-10-31

    Myocardial ischemic preconditioning upregulated protein 1 (Mipu1) is a newly discovered upregulated gene produced in rats during the myocardial ischemic preconditioning process. Mipu1 cDNA contains a 1824-base pair open reading frame and encodes a 608 amino acid protein with an N-terminal Krüppel-associated box (KRAB) domain and classical zinc finger C2H2 motifs in the C-terminus. Mipu1 protein is located in the cell nucleus. Recent studies found that Mipu1 has a protective effect on the ischemia-reperfusion injury of heart, brain, and other organs. As a nuclear factor, Mipu1 may perform its protective function through directly transcribing and repressing the expression of proapoptotic genes to repress cell apoptosis. In addition, Mipu1 also plays an important role in regulating the gene expression of downstream inflammatory mediators by inhibiting the activation of activator protein-1 and serum response element. PMID:25372717

  18. Essential role of EGFR in cardioprotection and signaling responses to A1 adenosine receptors and ischemic preconditioning.

    PubMed

    Williams-Pritchard, Grant; Knight, Matthew; Hoe, Louise See; Headrick, John P; Peart, Jason N

    2011-06-01

    Transactivation of epidermal growth factor receptor (EGFR) may contribute to specific protective responses (e.g. mediated by ?-opioid, bradykinin, or muscarinic receptors). No studies have assessed EGFR involvement in cardioprotection mediated by adenosine receptors (ARs), and the role of EGFR in ischemic preconditioning (IPC) is unclear. We tested EGFR, matrix metalloproteinase (MMP), and heparin-binding EGF (HB-EGF) dependencies of functional protection via A(1)AR agonism or IPC. Pretreatment of mouse hearts with 100 nM of A(1)AR agonist 2-chloro-N(6)-cyclopentyladenosine (CCPA) or IPC (3 × 1.5-min ischemia/2-min reperfusion) substantially improved recovery from 25-min ischemia, reducing left ventricular diastolic dysfunction up to 50% and nearly doubling pressure development and positive change in pressure over time (+dP/dt). Benefit with both CCPA and IPC was eliminated by inhibitors of EGFR tyrosine kinase (0.3 ?M AG1478), MMP (0.3 ?M GM6001), or HB-EGF ligand (0.3 ng/ml CRM197), none of which independently altered postischemic outcome. Phosphorylation of myocardial EGFR, Erk1/2, and Akt increased two- to threefold during A(1)AR agonism, with responses blocked by AG1478, GM6001, and CRM197. Studies in HL-1 myocytes confirm A(1)AR-dependent Erk1/2 phosphorylation is negated by AG1478 or GM6001, and reduced with CRM197 (as was Akt activation). These data collectively reveal that A(1)AR- and IPC-mediated functional protection is entirely EGFR and MMP dependent, potentially involving the HB-EGF ligand. Myocardial survival kinase activation (Erk1/2, Akt) by A(1)AR agonism is similarly MMP/HB-EGF/EGFR dependent. Thus MMP-mediated EGFR activation appears essential to cardiac protection and signaling via A(1)ARs and preconditioning. PMID:21460200

  19. Transferred inter-cell ischemic preconditioning-induced neuroprotection may be mediated by adenosine A1 receptors.

    PubMed

    Yun, Jungyeon; Li, Jun; Zuo, Zhiyi

    2014-04-01

    Ischemic preconditioning-induced neuroprotection is a well-known phenomenon. We hypothesize that this form of neuroprotection is transferable among the same type of cells. To test this hypothesis, human neuroblastoma SH-SY5Y cells were induced to become neuron-like cells. Primary rat cortical neuronal cultures were also used. These cells were subjected to various lengths of short oxygen-glucose deprivation (OGD, an in vitro simulation of ischemia) and then 1-h OGD. Some cells that were not exposed to a short episode of ischemia were incubated with culture medium from the cells that had 3- or 5-min OGD. Those cells were subjected to OGD for 1h at 1 or 24h after they were exposed to the medium. Cell injury was evaluated at 24h after the 1-h OGD by lactate dehydrogenase release assay. In another experiment, cells subjected to a 3-min OGD or exposed to the medium from cells that had a 3-min OGD were harvested at 30min after the OGD or the medium exposure for Western blotting of Akt, a prosurvival protein. Our study showed that a prior episode of ischemia lasting from 3 to 10min significantly reduced the 1-h OGD-induced cell injury. Medium from cells subjected to a 3-min OGD also induced acute and delayed phases of neuroprotection in OGD-naïve human neuron-like cells and primary rat cortical neuronal cultures. Cells subjected to a 3-min OGD or incubated with the medium from cells exposed to a 3-min OGD had increased phosphorylated/activated Akt. The increased phosphorylated Akt and neuroprotection induced by medium transferring were inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an adenosine A1 receptor inhibitor. The 3-min OGD-induced neuroprotection was inhibited by LY294002, an Akt activation inhibitor. These results suggest that ischemic preconditioning-induced neuroprotection is transferable among the cells. Small molecules, such as adenosine, may mediate this effect. PMID:24613761

  20. Ischemic preconditioning prevents the impairment of hypoxic coronary vasodilatation caused by ischemia/reperfusion: role of adenosine A1/A3 and bradykinin B2 receptor activation.

    PubMed

    Giannella, E; Mochmann, H C; Levi, R

    1997-09-01

    We previously reported that hypoxic coronary vasodilatation (HCVD) is initiated by endothelial NO and sustained by adenosine. Prolonged ischemia/reperfusion impairs endothelium-dependent coronary vasodilatation, whereas transient ischemia (ie, preconditioning) protects the myocardium from subsequent ischemic events. Accordingly, we assessed whether prolonged ischemia/reperfusion impairs HCVD and whether preconditioning prevents this dysfunction. HCVD, elicited in isolated guinea pig hearts by a 1-minute exposure to 100% N2, consisted of an approximately 70% increase in coronary flow associated with enhanced nitrite/nitrate and adenosine overflow (+40% and 5-fold, respectively). After 30-minute global ischemia and 20-minute reperfusion, HCVD was decreased by approximately 60%, and the increases in nitrite/nitrate and adenosine overflow were abolished. Preconditioning (ie, three cycles of 5-minute global ischemia+5-minute reperfusion) prevented the impairment of HCVD and fully restored the increase in nitrite/nitrate overflow, but not that of adenosine. The protective effect of preconditioning was mimicked by perfusion with the adenosine A1 receptor agonist N6-cyclopentyladenosine and prevented by the A1 receptor antagonist N-0861. In addition, the A3 receptor agonist N6-(3-iodobenzyl)adenosine-5'-N-methyl-carboxamide had a similar protective effect. The bradykinin B2 receptor antagonist HOE 140 abolished the protective effect of preconditioning, whereas the NO synthase inhibitor N(omega)-methyl-L-arginine and the cycloxygenase inhibitor indomethacin did not. Our data indicate that preconditioning restores HCVD by a process that is triggered by activation of adenosine A1/A3 and bradykinin B2 receptors. The action of bradykinin is independent of NO and prostacyclin production. Once restored by preconditioning, HCVD is mediated by NO but no longer sustained by adenosine. PMID:9285644

  1. Characterization of acute ischemia-related physiological responses associated with remote ischemic preconditioning: a randomized controlled, crossover human study.

    PubMed

    Sharma, Vikram; Cunniffe, Brian; Verma, Amit P; Cardinale, Marco; Yellon, Derek

    2014-11-01

    Remote Ischemic Preconditioning (RIPC) is emerging as a new noninvasive intervention that has the potential to protect a number of organs against ischemia-reperfusion (IR) injury. The standard protocols normally used to deliver RIPC involve a number of cycles of inflation of a blood pressure (BP) cuff on the arm and/or leg to an inflation pressure of 200 mmHg followed by cuff deflation for a short period of time. There is little evidence to support what limb (upper or lower) or cuff inflation pressures are most effective to deliver this intervention without causing undue discomfort/pain in nonanesthetized humans. In this preliminary study, a dose-response assessment was performed using a range of cuff inflation pressures (140, 160, and 180 mmHg) to induce limb ischemia in upper and lower limbs. Physiological changes in the occluded limb and any pain/discomfort associated with RIPC with each cuff inflation pressure were determined. Results showed that ischemia can be induced in the upper limb at much lower cuff inflation pressures compared with the standard 200 mmHg pressure generally used for RIPC, provided the cuff inflation pressure is ~30 mmHg higher than the resting systolic BP. In the lower limb, a higher inflation pressure, (~55 mmHg > resting systolic BP), is required to induce ischemia. Cyclical changes in capillary blood O2, CO2, and lactate levels during the RIPC stimulus were observed. RIPC at higher cuff inflation pressures of 160 and 180 mmHg was better tolerated in the upper limb. In summary, limb ischemia for RIPC can be more easily induced at lower pressures and is much better tolerated in the upper limb in young healthy individuals. However, whether benefits of RIPC can also be derived with protocols delivered to the upper limb using lower cuff inflation pressures and with lesser discomfort compared to the lower limb, remains to be investigated. PMID:25413320

  2. Remote Ischemic Preconditioning in Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Single?Center Double?Blinded Randomized Trial

    PubMed Central

    McCrindle, Brian W.; Clarizia, Nadia A.; Khaikin, Svetlana; Holtby, Helen M.; Manlhiot, Cedric; Schwartz, Steven M.; Caldarone, Christopher A.; Coles, John G.; Van Arsdell, Glen S.; Scherer, Stephen W.; Redington, Andrew N.

    2014-01-01

    Background Remote ischemic preconditioning (RIPC) harnesses an innate defensive mechanism that protects against inflammatory activation and ischemia?reperfusion injury, known sequelae of cardiac surgery with cardiopulmonary bypass. We sought to determine the impact of RIPC on clinical outcomes and physiological markers related to ischemia?reperfusion injury and inflammatory activation after cardiac surgery in children. Methods and Results Overall, 299 children (aged neonate to 17 years) were randomized to receive an RIPC stimulus (inflation of a blood pressure cuff on the left thigh to 15 mm Hg above systolic for four 5?minute intervals) versus a blinded sham stimulus during induction with a standardized anesthesia protocol. Primary outcome was duration of postoperative hospital stay, with serial clinical and laboratory measurements for the first 48 postoperative hours and clinical follow?up to discharge. There were no significant baseline differences between RIPC (n=148) and sham (n=151). There were no in?hospital deaths. No significant difference in length of postoperative hospital stay was noted (sham 5.4 versus RIPC 5.6 days; difference +0.2; adjusted P=0.91), with the 95% confidence interval (?0.7 to +0.9) excluding a prespecified minimal clinically significant differences of 1 or 1.5 days. There were few significant differences in other clinical outcomes or values at time points or trends in physiological markers. Benefit was not observed in specific subgroups when explored through interactions with categories of age, sex, surgery type, Aristotle score, or first versus second half of recruitment. Adverse events were similar (sham 5%, RIPC 6%; P=0.68). Conclusions RIPC is not associated with important improvements in clinical outcomes and physiological markers after cardiac surgery in children. Clinical Trial Registration URL: clinicaltrials.gov. Unique identifier: NCT00650507. PMID:25074698

  3. Ischemic preconditioning accelerates muscle deoxygenation dynamics and enhances exercise endurance during the work-to-work test

    PubMed Central

    Kido, Kohei; Suga, Tadashi; Tanaka, Daichi; Honjo, Toyoyuki; Homma, Toshiyuki; Fujita, Satoshi; Hamaoka, Takafumi; Isaka, Tadao

    2015-01-01

    Ischemic preconditioning (IPC) improves maximal exercise performance. However, the potential mechanism(s) underlying the beneficial effects of IPC remain unknown. The dynamics of pulmonary oxygen uptake (VO2) and muscle deoxygenation during exercise is frequently used for assessing O2 supply and extraction. Thus, this study examined the effects of IPC on systemic and local O2 dynamics during the incremental step transitions from low- to moderate- and from moderate- to severe-intensity exercise. Fifteen healthy, male subjects were instructed to perform the work-to-work cycling exercise test, which was preceded by the control (no occlusion) or IPC (3 × 5 min, bilateral leg occlusion at >300 mmHg) treatments. The work-to-work test was performed by gradually increasing the exercise intensity as follows: low intensity at 30 W for 3 min, moderate intensity at 90% of the gas exchange threshold (GET) for 4 min, and severe intensity at 70% of the difference between the GET and VO2 peak until exhaustion. During the exercise test, the breath-by-breath pulmonary VO2 and near-infrared spectroscopy-derived muscle deoxygenation were continuously recorded. Exercise endurance during severe-intensity exercise was significantly enhanced by IPC. There were no significant differences in pulmonary VO2 dynamics between treatments. In contrast, muscle deoxygenation dynamics in the step transition from low- to moderate-intensity was significantly faster in IPC than in CON (27.2 ± 2.9 vs. 19.8 ± 0.9 sec, P < 0.05). The present findings showed that IPC accelerated muscle deoxygenation dynamics in moderate-intensity exercise and enhanced severe-intensity exercise endurance during work-to-work test. The IPC-induced effects may result from mitochondrial activation in skeletal muscle, as indicated by the accelerated O2 extraction. PMID:25952936

  4. Activation of Nrf2 by ischemic preconditioning and sulforaphane in renal ischemia/reperfusion injury: a comparative experimental study.

    PubMed

    Shokeir, A A; Barakat, N; Hussein, A M; Awadalla, A; Harraz, A M; Khater, S; Hemmaid, K; Kamal, A I

    2015-06-11

    Objectives of the study were to investigate impact of ischemic preconditioning (Ipre) and sulforaphane (SFN) and combination of them on nuclear factor 2 erythroid related factor 2 (Nrf2) gene and its dependent genes, heme oxygenase-1 (HO1) and NADPH-quinone oxidoreductase1 (NQO-1) and inflammatory cytokines TNF-alpha, IL1beta, and intercellular adhesion molecule-1 (ICAM1) and caspase-3 in renal ischemia/reperfusion (I/R) injury. Ninety male Sprague Dawely rats were classified into 5 groups (each consists of 18 rats): sham, control, Ipre, sulforaphane and Sulfo+Ipre. Each group was subdivided into 3 subgroups each containing 6 rats according to time of harvesting kidney and taking blood samples; 24 h, 48 h, and 7 days subgroups. Renal functions including serum creatinine, BUN were measured at basal conditions and by the end of experiment. Expression of Nrf2, HO-1, NQO-1, TNF-alpha, IL-1beta, and ICAM-1 was measured by real time PCR in kidney tissues by the end of experiment. Also, immunohistochemical localization of caspase-3 and chemical assay of malondialdehyde (MDA), GSH and SOD activity were measured in kidney tissues. Both Ipre and SFN improved kidney functions, enhanced the expression of Nrf2, HO-1, and NQO-1, attenuated the expression of inflammatory (TNF-alpha, IL-1, and ICAM-1) and apoptotic (caspase-3) markers. However, the effect of sulforaphane was more powerful than Ipre. Also, a combination of them caused more improvement in antioxidant genes expression and more attenuation in inflammatory genes but not caspase-3 than each one did separately. Sulforaphane showed more powerful effect in renoprotection against I/R injury than Ipre as well as there might be a synergism between them at the molecular but not at the function level. PMID:25536319

  5. Functional preservation of hippocampal CA1 by low-dose GYKI-52466 preconditioning in a rat model of hypoxic-ischemic brain injury.

    PubMed

    Nayak, Prasanta K; Kerr, D Steven

    2015-07-10

    Global ischemia during cardiac surgery, brain surgery and stroke leads to lasting neuropsychological impairments. Previously we showed that low-dose GYKI-52466 preconditioning protects against kainic acid-induced seizures and unilateral hypoxic-ischemic (HI) damage in rats. Here, we evaluated low-dose GYKI-52466 on electrophysiological indices of hippocampal CA1 function after HI. Male Sprague-Dawley rats (26 days old) were administered saline or GYKI-52466 (3mg/kg, s.c.) 90min before left common carotid artery occlusion and allowed to recover 2h prior to placement in a hypoxia chamber (1h; 8% O2/92% N2). On days 14 and 90 post-HI, contralateral and, where possible, ipsilateral hippocampal slices were prepared and population spikes and field excitatory postsynaptic potentials (EPSPs) recorded at 30-32°C. Slices with population spikes ?3mV and/or field EPSPs ?1mV were accepted for long-term potentiation (LTP) and depression (LTD) studies. GYKI-52466 preconditioning prevented the stroke-induced suppression of population spikes and field EPSPs in both contralateral and ipsilateral hippocampi at 14 and 90 days. On days 14 and 90, both LTP and LTD were readily induced in both contralateral and ipsilateral hippocampi from sham-operated controls. After stroke, LTP was significantly impaired in contralateral and completely absent in ipsilateral hippocampi. In ischemic animals preconditioned with low-dose GYKI-52466, LTP was readily induced on both sides. Hippocampal LTD was unaffected by either HI or GYKI preconditioning on both days 14 and 90. The present results indicate that prophylactic low-dose GYKI-52466 preserves CA1 function and synaptic plasticity processes contralateral, and more importantly, ipsilateral to the site of damage. PMID:25869178

  6. Dynamic Changes in DNA Methylation in Ischemic Tolerance

    PubMed Central

    Meller, Robert; Pearson, Andrea; Simon, Roger P.

    2015-01-01

    Epigenetic mediators of gene expression are hypothesized to regulate transcriptomic responses to preconditioning ischemia and ischemic tolerance. Here, we utilized a methyl-DNA enrichment protocol and sequencing (ChIP-seq) to identify patterns of DNA methylation in an established model of ischemic tolerance in neuronal cultures (oxygen and glucose deprivation: OGD). We observed an overall decrease in global DNA methylation at 4?h following preconditioning ischemia (30?min OGD), harmful ischemia (120?min OGD), and in ischemic tolerant neuronal cultures (30?min OGD, 24?h recovery, 120?min OGD). We detected a smaller cohort of hypermethylated regions following ischemic conditions, which were further analyzed revealing differential chromosomal localization of methylation, and a differential concentration of methylation on genomic regions. Together, these data show that the temporal profiles of DNA methylation with respect to chromatin hyper- and hypo-methylation following various ischemic conditions are highly dynamic, and may reveal novel targets for neuroprotection. PMID:26029158

  7. Negative regulation of diacylglycerol kinase ? mediates adenosine-dependent hepatocyte preconditioning

    Microsoft Academic Search

    G Baldanzi; E Alchera; C Imarisio; M Gaggianesi; C Dal Ponte; M Nitti; C Domenicotti; W J van Blitterswijk; E Albano; A Graziani; R Carini

    2010-01-01

    In liver ischemic preconditioning (IP), stimulation of adenosine A2a receptors (A2aR) prevents ischemia\\/reperfusion injury by promoting diacylglycerol-mediated activation of protein kinase C (PKC). By concerting diacylglycerol to phosphatidic acid, diacylglycerol kinases (DGKs) act as terminator of diacylglycerol signalling. This study investigates the role of DGK in the development of hepatocyte IP. DGK activity and cell viability were evaluated in isolated

  8. Ischemic preconditioning potentiates the protective effect of mesenchymal stem cells on endotoxin-induced acute lung injury in mice through secretion of exosome

    PubMed Central

    Li, Lingxia; Jin, Shuan; Zhang, Yingmin

    2015-01-01

    Objective: To explore the effect of bone marrow mesenchymal stem cells (MSCs) on endotoxin-induced acute lung injury in mice and verify the role of exosome. Methods: Exosome was isolated from the culture supernatant of MSC. For ischemic preconditioning, MSCs were subjected to anoxia for 0 min (MSCs group), 30 min (MSCsIPC-30 group), 60 min (MSCsIPC-60 group) and 90 min (MSCsIPC 90 group), and then used to treat endotoxin-injured mice. The exosome from the optimal group was used to treat endotoxin-injured mice. In addition, the exosome from the optimal group was also used to treat the endotoxin-stimulated RAW 264.7 cells for 6 h and 12 h. Results: CD63 positive exosome were acquired through ExoQuick kits. Administration of MSCs, MSCsIPC-30, MSCsIPC-60 and MSCsIPC-90 could reduce the level of white blood cells (WBC) and neutrophils into the bronchoalveolar lavage (BAL) fluid of endotoxin-injured mice, and the MSCIPC-60 group had the greatest reduction, which reduced WBC by 57% and neutrophils by 55%. Administration of MSCsIPC-60 exosome could also reduce the level of WBC, neutrophils, MIP-2 and penetration protein into the BAL fluid of endotoxin-injured mice, which had the same effect as MSCsIPC-60 and showed a dose dependent, compared to MSCs exosome. In addition, MSCsIPC-60 exosome were used to treat endotoxin-stimulated RAW 264.7 cells, and the level of TNF? at 6 h and 12 h was significantly reduced, while the level of IL-10 at 12 h increased. Conclusion: Ischemic preconditioning for 60 min can potentiates the protective effect of MSC on endotoxin-induced Acute Lung Injury through the secretion of Exosome.

  9. Ischemic preconditioning protects neurons from damage and maintains the immunoreactivity of kynurenic acid in the gerbil hippocampal CA1 region following transient cerebral ischemia

    PubMed Central

    LEE, JAE-CHUL; TAE, HYUN-JIN; CHO, GEUM-SIL; KIM, IN HYE; AHN, JI HYEON; PARK, JOON HA; CHEN, BAI HUI; CHO, JEONG-HWI; SHIN, BICH NA; CHO, JUN HWI; BAE, EUN JOO; PARK, JINSEU; KIM, YOUNG-MYEONG; CHOI, SOO YOUNG; WON, MOO-HO

    2015-01-01

    Pyramidal neurons in region I of hippocampus proper (CA1) are particularly vulnerable to excitotoxic processes following transient forebrain ischemia. Kynurenic acid (KYNA) is a small molecule derived from tryptophan when this amino acid is metabolized through the kynurenine pathway. In the present study, we examined the effects of ischemic preconditioning (IPC) on the immunoreactivity and protein levels of KYNA following 5 min of transient forebrain ischemia in gerbils. The animals were randomly assigned to 4 groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia followed by 1 day of recovery. In the ischemia-operated group, we observed a significant loss of pyramidal neurons in the CA1 stratum pyramidale (SP) at 5 days post-ischemia; however, in the IPC + ischemia-operated group, the pyramidal neurons were well protected. KYNA immunoreactivity in the SP of the ischemia-operated group was significantly altered following ischemia-reperfusion and was very low 5 days following ischemia-reperfusion. In the IPC + ischemia-operated group, however, KYNA immunoreactivity was constitutively detected in the SP of the CA1 region after the ischemic insult. We also found that the alteration pattern of the KYNA protein level in the CA1 region following ischemia was generally similar to the immunohistochemical changes observed. In brief, our findings demonstrated that IPC maintained and even increased KYNA immunoreactivity in the SP of the CA1 region following ischemia-reperfusion. The data from the present study thus indicate that the enhancement of KYNA expression by IPC may be necessary for neuronal survival following transient ischemic injury. PMID:25872573

  10. Ischemic preconditioning protects neurons from damage and maintains the immunoreactivity of kynurenic acid in the gerbil hippocampal CA1 region following transient cerebral ischemia.

    PubMed

    Lee, Jae-Chul; Tae, Hyun-Jin; Cho, Geum-Sil; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Chen, Bai Hui; Cho, Jeong-Hwi; Shin, Bich Na; Cho, Jun Hwi; Bae, Eun Joo; Park, Jinseu; Kim, Young-Myeong; Choi, Soo Young; Won, Moo-Ho

    2015-06-01

    Pyramidal neurons in region I of hippocampus proper (CA1) are particularly vulnerable to excitotoxic processes following transient forebrain ischemia. Kynurenic acid (KYNA) is a small molecule derived from tryptophan when this amino acid is metabolized through the kynurenine pathway. In the present study, we examined the effects of ischemic preconditioning (IPC) on the immunoreactivity and protein levels of KYNA following 5 min of transient forebrain ischemia in gerbils. The animals were randomly assigned to 4 groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia followed by 1 day of recovery. In the ischemia-operated group, we observed a significant loss of pyramidal neurons in the CA1 stratum pyramidale (SP) at 5 days post-ischemia; however, in the IPC + ischemia-operated group, the pyramidal neurons were well protected. KYNA immunoreactivity in the SP of the ischemia-operated group was significantly altered following ischemia-reperfusion and was very low 5 days following ischemia?reperfusion. In the IPC + ischemia-operated group, however, KYNA immunoreactivity was constitutively detected in the SP of the CA1 region after the ischemic insult. We also found that the alteration pattern of the KYNA protein level in the CA1 region following ischemia was generally similar to the immunohistochemical changes observed. In brief, our findings demonstrated that IPC maintained and even increased KYNA immunoreactivity in the SP of the CA1 region following ischemia?reperfusion. The data from the present study thus indicate that the enhancement of KYNA expression by IPC may be necessary for neuronal survival following transient ischemic injury. PMID:25872573

  11. Time-dependent profiles of microRNA expression induced by ischemic preconditioning in the gerbil hippocampus.

    PubMed

    Sun, Miao; Yamashita, Toru; Shang, Jingwei; Liu, Ning; Deguchi, Kentaro; Feng, Juan; Abe, Koji

    2015-01-01

    MicroRNAs (miRNAs) are critically important in both normal neuronal development and neurological diseases. Although cerebral ischemia has been shown to alter the miRNA profiles of rats, the role of miRNA in the cornu ammonis 1 region of the gerbil hippocampus under ischemic tolerance has not been studied. In the present study, Mongolian gerbils were subjected to one or three times the nonlethal dose of 2-min transient common carotid artery occlusion (tCCAO). miRNA microarray technology detected 251 miRNAs and the expression of seven of these in terms of ischemic tolerance. They were compared at different time points: 1 day, 7 days, 1 month, and 6 months. mmu-miR-15a-5p, related to neurogenesis, showed increased expression after one dose of 2-min tCCAO and was much higher after three doses. An increase in sha-miR-24 and oan-let-7b-3p, related to transactivation response DNA-binding protein (TDP43), was observed after one dose of 2-min tCCAO, but the peak was accelerated to an earlier period of reperfusion after three doses. In contrast, mmu-miR-125b-5p and mmu-miR-132-5p, related to fused in sarcoma/translocated in liposarcoma (FUS/TLS), showed similar increases at both doses. mmu-miR-181c-5p and mmu-miR-378a-5p, related to heat shock protein 70 (HSP70), also showed accelerated expression after three doses. This data set provides new insight about miRNA expression during neurogenesis, and related to TDP43, FUS/TLS, and HSP70, which may be useful when pursuing further studies on the possible use of miRNAs as biomarkers in cerebral ischemic tolerance and neuroregeneration. PMID:25646661

  12. Rho-kinase inhibition is involved in the activation of PI3-kinase/Akt during ischemic-preconditioning-induced cardiomyocyte apoptosis

    PubMed Central

    Zhang, Juan; Liu, Xiao-Bo; Cheng, Chao; Xu, Dong-Ling; Lu, Qing-Hua; Ji, Xiao-Ping

    2014-01-01

    We and others have reported that Rho-kinase plays an important role in the pathogenesis of heart ischemia/reperfusion (I/R) injury. Studies also have demonstrated that the activation of Rho-kinase was reversed in ischemic preconditioning (IPC). This study aimed to explain the mechanism of Rho-kinase-mediated cardiomyocyte apoptosis increased in I/R and reversed in IPC. Materials and methods: Studies were performed with female Wistar rats. The I/R rats were created by ligating the left anterior descending branch (LAD) for 30 min and releasing the ligature for 180 min. The IPC rats underwent IPC (two cycles of 5 min ligation of the LAD and 5 min reflow) before I/R. Results: Ischemia followed by reperfusion caused a significant increase in Rho-kinase and a decrease in Akt phosphorylation. Administration of fasudil, an inhibitor of Rho-kinase, decreased myocardial infarction size and cardiomyocyte apoptosis and increased Akt activation. IPC also caused the reduced Rho-kinase activity and cardiomyocyte apoptosis and a significant increase in Akt activity (P<0.05 vs I/R). Conclusion: Rho-kinase inhibition by IPC leads to reduced cardiomyocyte apoptosis may be mediated by activation of PI3-kinase/Akt. PMID:25550920

  13. Cardiac genomic response following preconditioning stimulus

    Microsoft Academic Search

    Dipak K. Das; Nilanjana Maulik

    2006-01-01

    This review focuses on the genomic response following a preconditioning stimulus. Initial studies demonstrated that classical ischemic preconditioning mediated by cyclic episodes of short durations of reversible ischemia and reperfusion could result in the reprogramming of gene expression. Some of these genes are translated into proteins during the late preconditioning or so-called ''second window of protection''. Subsequent studies determined a

  14. Isoflurane preconditioning provides neuroprotection against stroke by regulating the expression of the TLR4 signalling pathway to alleviate microglial activation

    PubMed Central

    Sun, Meiyan; Deng, Bin; Zhao, Xiaoyong; Gao, Changjun; Yang, Lu; Zhao, Hui; Yu, Daihua; Zhang, Feng; Xu, Lixian; Chen, Lei; Sun, Xude

    2015-01-01

    Excessive microglial activation often contributes to inflammation-mediated neurotoxicity in the ischemic penumbra during the acute stage of ischemic stroke. Toll-like receptor 4 (TLR4) has been reported to induce microglial activation via the NF-?B pathway. Isoflurane preconditioning (IP) can provide neuroprotection and inhibit microglial activation. In this study, we investigated the roles of the TLR4 signalling pathway in IP to exert neuroprotection following ischemic stroke in vivo and in vitro. The results showed that 2% IP alleviated neurological deficits, reduced the infarct volume, attenuated apoptosis and weakened microglial activation in the ischemic penumbra. Furthermore, IP down-regulated the expression of HSP 60, TLR4 and MyD88 and up-regulated inhibitor of I?B-? expression compared with I/R group in vivo. In vitro, 2% IP and a specific inhibitor of TLR4, CLI-095, down-regulated the expression of TLR4, MyD88, IL-1?, TNF-? and Bax, and up-regulated I?B-? and Bcl-2 expression compared with OGD group. Moreover, IP and CLI-095 attenuated microglial activation-induced neuronal apoptosis, and overexpression of the TLR4 gene reversed the neuroprotective effects of IP. In conclusion, IP provided neuroprotection by regulating TLR4 expression directly, alleviating microglial activation and neuroinflammation. Thus, inhibiting the activation of microglial activation via TLR4 may be a new avenue for stroke treatment. PMID:26086415

  15. Isoflurane preconditioning provides neuroprotection against stroke by regulating the expression of the TLR4 signalling pathway to alleviate microglial activation.

    PubMed

    Sun, Meiyan; Deng, Bin; Zhao, Xiaoyong; Gao, Changjun; Yang, Lu; Zhao, Hui; Yu, Daihua; Zhang, Feng; Xu, Lixian; Chen, Lei; Sun, Xude

    2015-01-01

    Excessive microglial activation often contributes to inflammation-mediated neurotoxicity in the ischemic penumbra during the acute stage of ischemic stroke. Toll-like receptor 4 (TLR4) has been reported to induce microglial activation via the NF-?B pathway. Isoflurane preconditioning (IP) can provide neuroprotection and inhibit microglial activation. In this study, we investigated the roles of the TLR4 signalling pathway in IP to exert neuroprotection following ischemic stroke in vivo and in vitro. The results showed that 2% IP alleviated neurological deficits, reduced the infarct volume, attenuated apoptosis and weakened microglial activation in the ischemic penumbra. Furthermore, IP down-regulated the expression of HSP 60, TLR4 and MyD88 and up-regulated inhibitor of I?B-? expression compared with I/R group in vivo. In vitro, 2% IP and a specific inhibitor of TLR4, CLI-095, down-regulated the expression of TLR4, MyD88, IL-1?, TNF-? and Bax, and up-regulated I?B-? and Bcl-2 expression compared with OGD group. Moreover, IP and CLI-095 attenuated microglial activation-induced neuronal apoptosis, and overexpression of the TLR4 gene reversed the neuroprotective effects of IP. In conclusion, IP provided neuroprotection by regulating TLR4 expression directly, alleviating microglial activation and neuroinflammation. Thus, inhibiting the activation of microglial activation via TLR4 may be a new avenue for stroke treatment. PMID:26086415

  16. Volatile anesthetic-induced preconditioning.

    PubMed

    Swyers, T; Redford, D; Larson, D F

    2014-01-01

    The myocardium has an innate ability to protect itself from ischemic events. This protection occurs when the myocardium is exposed to a brief ischemic period prior to a more extreme ischemic event. This is termed ischemic preconditioning. Ischemic preconditioning induces a series of molecular pathways that protect the cardiac myocyte; first, for a period of 1-6 hours (early preconditioning) and, also, for a second period from 24-72 hours (delayed phase). The early preconditioning is mediated by the release of adenosine which induces a protective signal that is related to the mitochondrial KATP channel activation and activation of the ?-opioid and bradykinin receptors. The delayed phase is related to the induction of inducible nitric oxide synthase, superoxide dismutase and heat-shock proteins. Indirect evidence indicates that O2-derived free radicals are involved in the delayed phase, as noted in the early preconditioning phase. Applying ischemic preconditioning to clinical practice can be dangerous and difficult to implement in a controlled fashion. However, recent studies have shown that the use of volatile anesthetics, such as sevoflurane, isoflurane and desflurane, can mimic the early phase of ischemic preconditioning through a multi-pathway signaling of mitochondrial KATP channels. This important finding can easily be applied to clinical practice for patients undergoing surgery. It can also be significantly important for patients undergoing off-pump cardiac bypass surgery or cardiac bypass surgery where there is no cross-clamp or cardioplegia used where the probability of myocardial ischemia is greatly increased. This report will, therefore, discuss the mechanism, safety and efficacy of volatile anesthetics as inducers of cardiac preconditioning. PMID:24002781

  17. ARL6IP6, a susceptibility locus for ischemic stroke, is mutated in a patient with syndromic Cutis Marmorata Telangiectatica Congenita.

    PubMed

    Abumansour, Iman S; Hijazi, Hadia; Alazmi, Anas; Alzahrani, Fatma; Bashiri, Fahad A; Hassan, Hamdy; Alhaddab, Mohammed; Alkuraya, Fowzan S

    2015-08-01

    Cutis Marmorata Telangiectatica Congenita (CMTC) is a congenital localized or generalized vascular anomaly, usually sporadic in occurrence. It can be associated with other cutaneous or systemic manifestations. About 300 cases have been reported. The molecular etiology remains largely unknown. The main purpose of this study is to delineate the molecular basis for a syndromic CMTC phenotype in a consanguineous Saudi family. Clinical phenotyping including detailed neurological imaging, followed by autozygosity mapping and trio whole exome sequencing (WES) are also studied. We have identified a homozygous truncating mutation in ARL6IP6 as the likely cause of a syndromic form of CMTC associated with major dysmorphism, developmental delay, transient ischemic attacks and cerebral vascular malformations. This gene was previously implicated by genome wide association study (GWAS) as a susceptibility locus to ischemic stroke in young adults. We identify ARL6IP6 as a novel candidate gene for a syndromic form of CMTC. This suggests that ischemic stroke or transient ischemic attacks (TIA) may represent, at least in some cases, the mild end of a phenotypic spectrum that has at its severe end autosomal recessive CMTC. This finding contributes to a growing appreciation of the continuum of Mendelian and common complex diseases. PMID:25957586

  18. Liver Ischemic Preconditioning (IPC) Improves Intestinal Microbiota Following Liver Transplantation in Rats through 16s rDNA-Based Analysis of Microbial Structure Shift

    PubMed Central

    Lu, Haifeng; Chen, Xinhua; Jiang, Jianwen; Liu, Hui; He, Yong; Ding, Songming; Hu, Zhenhua; Wang, Weilin; Zheng, Shusen

    2013-01-01

    Background Ischemia-reperfusion (I/R) injury is associated with intestinal microbial dysbiosis. The “gut-liver axis” closely links gut function and liver function in health and disease. Ischemic preconditioning (IPC) has been proven to reduce I/R injury in the surgery. This study aims to explore the effect of IPC on intestinal microbiota and to analyze characteristics of microbial structure shift following liver transplantation (LT). Methods The LT animal models of liver and gut IPC were established. Hepatic graft function was assessed by histology and serum ALT/AST. Intestinal barrier function was evaluated by mucosal ultrastructure, serum endotoxin, bacterial translocation, fecal sIgA content and serum TNF-?. Intestinal bacterial populations were determined by quantitative PCR. Microbial composition was characterized by DGGE and specific bacterial species were determined by sequence analysis. Principal Findings Liver IPC improved hepatic graft function expressed as ameliorated graft structure and reduced ALT/AST levels. After administration of liver IPC, intestinal mucosal ultrastructure improved, serum endotoxin and bacterial translocation mildly decreased, fecal sIgA content increased, and serum TNF-? decreased. Moreover, liver IPC promoted microbial restorations mainly through restoring Bifidobacterium spp., Clostridium clusters XI and Clostridium cluster XIVab on bacterial genus level. DGGE profiles indicated that liver IPC increased microbial diversity and species richness, and cluster analysis demonstrated that microbial structures were similar and clustered together between the NC group and Liver-IPC group. Furthermore, the phylogenetic tree of band sequences showed key bacteria corresponding to 10 key band classes of microbial structure shift induced by liver IPC, most of which were assigned to Bacteroidetes phylum. Conclusion Liver IPC cannot only improve hepatic graft function and intestinal barrier function, but also promote restorations of intestinal microbiota following LT, which may further benefit hepatic graft by positive feedback of the “gut-liver axis”. PMID:24098410

  19. Liver ischemia preconditions the heart against ischemia-reperfusion arrhythmias

    PubMed Central

    Noorbakhsh, Mohammad-Foad; Arab, Hossein-Ali; Kazerani, Hamid-Reza

    2015-01-01

    Objective(s): This study aimed to examine the hypothesis that an antiarrhythmic effect might be obtained by ischemic preconditioning of the liver, and also to characterize the potential underlying mechanisms. Materials and Methods: Male Wistar rats were anesthetized by thiopental sodium (50 mg/kg, IP) followed by IV injection of heparin (250 IU). Remote ischemic preconditioning (RIPC) was induced by 3 cycles of 5 min liver ischemia followed by 5 min of reperfusion. The hearts were excised within 5 min after the final cycle of preconditioning and perfused using Langendorff’s system. The isolated perfused hearts were subjected to 30 min global ischemia followed by 90 min reperfusion. The myocardial arrhythmias induced by ischemia- reperfusion (I/R) were determined in accordance with the guidelines of Lambeth Conventions. The potential role of KATP channels on RIPC was assessed by injection of glibenclamide (nonselective KATP blocker) or 5-hydroxydecanoate (mitochondrial KATP blocker) on rats 30 and 15 min before induction of RIPC in the liver, respectively. Results: Hepatic remote preconditioning of the heart significantly (P<0.0001) prevented the incidence of myocardial arrhythmias induced by I/R in the perfused hearts (5.33±1.54 vs. 32.33±6.44,). However, the protective effects of remote preconditioning was significantly (P<0.01) abolished by the KATP blocker, glibenclamide (25.5±4.9 vs. 5.33±1.54,). Conclusion: Hepatic RIPC may prevent the arrhythmias induced by I/R in the isolated perfused hearts via KATP channels. PMID:25810880

  20. The effect of preconditioning on liver regeneration after hepatic resection in cirrhotic rats

    PubMed Central

    Min, Seon Ok; Kim, Sung Hoon; Lee, Sang Woo; Cho, Jin A

    2011-01-01

    Background/Aims Ischemic preconditioning (IP) decreases severity of liver necrosis and has anti-apoptotic effects in previous studies using liver regeneration in normal rats. This study assessed the effect of IP on liver regeneration after hepatic resection in cirrhotic rats. Methods To induce liver cirrhosis, thioacetamide (300 mg/kg) was injected intraperitoneally into Sprague-Dawley rats twice per week for 16 weeks. Animals were divided into four groups: non-clamping (NC), total clamping (TC), IP, and intermittent clamping (IC). Ischemic injury was induced by clamping the left portal pedicle including the portal vein and hepatic artery. Liver enzymes alanine transaminase (ALT) and aspartate aminotransferase (AST) were measured to assess liver damage. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining for apoptosis and proliferating cell nuclear antigen (PCNA) staining for cell replication were also performed. Results Day-1 ALT and AST were highest in IP, however, levels in NC and IC were comparably low on days 1-7. There was no significant correlation of AST or ALT with experimental groups (P=0.615 and P=0.186). On TUNEL, numbers of apoptotic cells at 100× magnification (cells/field) were 31.8±24.2 in NC, 69.0±72.3 in TC, 80.2±63.1 in IP, and 21.2±20.8 in IC (P<0.05). When regeneration capacity was assessed by PCNA staining, PCNA-positive cells (cells/field) at 400× were 3.4±6.0 in NC, 16.9±69 in TC, 17.0±7.8 in IP and 7.4±7.6 in IC (P<0.05). Conclusions Although regeneration capacity in IP is higher than IC, the liver is vulnerable to ischemic damage in cirrhotic rats. Careful consideration is needed in applying IP in the clinical setting. PMID:21757985

  1. Cyclooxygenase-2 Mediates Hyperbaric Oxygen Preconditioning in the Rat Model of Transient Global Cerebral Ischemia

    PubMed Central

    Cheng, Oumei; Ostrowski, Robert P.; Wu, Bihua; Liu, Wenwu; Chen, Chunhua; Zhang, John H.

    2010-01-01

    Background and Purpose Hyperbaric oxygen preconditioning (HBO-PC) affords brain protection against transient global ischemia. In the present study we hypothesize that the mechanism of HBO-PC involves the induction of cyclooxygenase-2 (COX-2) in cerebral tissues prior to ischemia, which leads to a suppression of COX-2 and its downstream targets after global ischemic insult. Methods One hundred twenty nine male Sprague Dawley (SD) rats (280–300g body weight) were allocated to the naïve control group, sham operation group, three groups of animals subjected to 15 min four-vessel occlusion (4VO): untreated, preconditioned with HBO 2.5 atmospheres absolutes (ATA) for 1 hour daily for 5 days, preconditioned as above and administered with COX-2 inhibitor, NS-398 (1 mg/kg bw i.p.) prior to each preconditioning session, as well as normal rats preconditioned with HBO without ischemia. The mortality, the incidence of seizures and T-maze scores were recorded. The quantitative cell count in Nissl stain and TUNEL was conducted on day 7 after ischemia. The brain expression of COX-2 was analyzed with Western blotting and immunofluorescence staining. Results HBO-PC increased the number of surviving neurons in the CA1, which was associated with the reduced COX-2 expression in the hippocampus and in the cerebral cortex at 1 and 3 days post-ischemia. HBO-PC improved functional performance and tended to decrease mortality and the frequency of seizures. These beneficial effects of HBO-PC were abolished by the COX-2 selective inhibitor, NS-398. Conclusions HBO-PC reduced COX-2 expression and provided brain protection after global ischemia. Administration of COX-2 inhibitor with HBO prior to ischemia, abolished preconditioning effect, thereby implicating COX-2 as a mediator of HBO-PC in the ischemic brain. PMID:21164135

  2. Negative regulation of diacylglycerol kinase theta mediates adenosine-dependent hepatocyte preconditioning.

    PubMed

    Baldanzi, G; Alchera, E; Imarisio, C; Gaggianesi, M; Dal Ponte, C; Nitti, M; Domenicotti, C; van Blitterswijk, W J; Albano, E; Graziani, A; Carini, R

    2010-06-01

    In liver ischemic preconditioning (IP), stimulation of adenosine A2a receptors (A2aR) prevents ischemia/reperfusion injury by promoting diacylglycerol-mediated activation of protein kinase C (PKC). By concerting diacylglycerol to phosphatidic acid, diacylglycerol kinases (DGKs) act as terminator of diacylglycerol signalling. This study investigates the role of DGK in the development of hepatocyte IP. DGK activity and cell viability were evaluated in isolated rat hepatocytes preconditioned by 10 min hypoxia followed by 10 min re-oxygenation or by the treatment with the A2aR agonist, CGS21680, and subsequently exposed to prolonged hypoxia. We observed that after IP or A2aR activation, a decrease in DGK activity was associated with the onset of hepatocyte tolerance to hypoxia. CGS21680-induced stimulation of A2aR specifically inhibited DGK isoform theta by activating RhoA-GTPase. Consistently, both siRNA-mediated downregulation of DGK theta and hepatocyte pretreatment with the DGK inhibitor R59949 induced cell tolerance to hypoxia. The pharmacological inhibition of DGK was associated with the diacylglycerol-dependent activation of PKC delta and epsilon and of their downstream target p38 MAPK. In conclusion, we unveil a novel signalling pathway contributing to the onset of hepatocyte preconditioning, which through RhoA-GTPase, couples A2aR to the downregulation of DGK. Such an inhibition is essential for the sustained accumulation of diacylglycerol required for triggering PKC-mediated survival signals. PMID:20057501

  3. Preconditioning Balloons

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students use balloons (a polymer) to explore preconditioning—a viscoelastic material behavior that is important to understand when designing biomedical devices. They improve their understanding of preconditioning by measuring the force needed to stretch a balloon to the same displacement multiple times. Students gain experience in data collection and graph interpretation.

  4. Differential expression of microRNAs in ischemic heart disease.

    PubMed

    Song, Minwoo A; Paradis, Alexandra N; Gay, Maresha S; Shin, John; Zhang, Lubo

    2015-02-01

    Recent studies provide evidence that ischemic preconditioning (IP) and ischemia/reperfusion (IR) injury lead to altered expression of microRNAs (miRNAs) that affect the survival and recovery of cardiomyocytes. These endogenous ?22-nucleotide noncoding RNAs negatively regulate gene expression via degradation and translational inhibition of their target mRNAs. miRNAs are involved in differentiation, proliferation, electrical conduction, angiogenesis and apoptosis. These pathways can lead to physiological and pathological adaptations. This review intends to explore several facets of miRNA expression and the underlying mechanisms involved in IR injury, as well as IP as a cardioprotective strategy. In addition, we will investigate miRNA interaction with the renin-angiotensin system and the potential use of miRNAs in developing sensitive biomarkers for cardiovascular disease. PMID:25461956

  5. Persimmon leaf flavonoid promotes brain ischemic tolerance

    PubMed Central

    Miao, Mingsan; Zhang, Xuexia; Bai, Ming; Wang, Linan

    2013-01-01

    Persimmon leaf flavonoid has been shown to enhance brain ischemic tolerance in mice, but its mechanism of action remains unclear. The bilateral common carotid arteries were occluded using a micro clip to block blood flow for 10 minutes. After 10 minutes of ischemic preconditioning, 200, 100, and 50 mg/kg persimmon leaf flavonoid or 20 mg/kg ginaton was intragastrically administered per day for 5 days. At 1 hour after the final administration, ischemia/reperfusion models were estab-lished by blocking the middle cerebral artery for 2 hours. At 24 hours after model establishment, compared with cerebral ischemic rats without ischemic preconditioning or drug intervention, plasma endothelin, thrombomodulin and von Willebrand factor levels significantly decreased and intercel-lular adhesion molecule-1 expression markedly reduced in brain tissue from rats with ischemic pre-conditioning. Simultaneously, brain tissue injury reduced. Ischemic preconditioning combined with drug exposure noticeably improved the effects of the above-mentioned indices, and the effects of 200 mg/kg persimmon leaf flavonoid were similar to 20 mg/kg ginaton treatment. These results indicate that ischemic preconditioning produces tolerance to recurrent severe cerebral ischemia. However, persimmon leaf flavonoid can elevate ischemic tolerance by reducing inflammatory reactions and vascular endothelial injury. High-dose persimmon leaf flavonoid showed an identical effect to ginaton. PMID:25206573

  6. The Akt Pathway Is Involved in Rapid Ischemic Tolerance in Focal Ischemia in Rats

    Microsoft Academic Search

    Xuwen Gao; Hanfeng Zhang; Gary Steinberg; Heng Zhao

    2010-01-01

    Although the protective mechanisms of delayed ischemic preconditioning have received extensive studies, few have addressed\\u000a the mechanisms associated with rapid ischemic preconditioning. We investigated whether ischemic tolerance induced by rapid\\u000a preconditioning is regulated by the Akt survival signaling pathway. Stroke was generated by permanent occlusion of the left\\u000a distal middle cerebral artery plus 30 min or 1 h occlusion of the bilateral

  7. The Effect of Pre-Condition Cerebella Fastigial Nucleus Electrical Stimulation within and beyond the Time Window of Thrombolytic on Ischemic Stroke in the Rats

    PubMed Central

    Cheng, Pengfei; Bai, Shunjie; Ren, Yifei; Wang, Gong; Chen, Xiuying; Cui, Chun; Zhuang, Yuxiang

    2015-01-01

    Objective To investigate the effect of neurogenic neuroprotection conferred by cerebellar fastigial nucleus stimulation (FNS) and the role of PPAR?- mediated inflammation in a rat model of cerebral ischemia reperfusion. Methods After a continuous 1 hour fastigial nucleus electric stimulation, the male Sprague Dawley (SD) rats were given middle cerebral artery occlusion (MCAO) for 1, 3, 6, 9, 12 and 15 hours undergoing reperfusion with intravenous recombinant tissue plasminogen activator (rt-PA), while the control group received without FNS. After 72h of reperfusion, the neurological deficits, infarct volume and brain edema were evaluated. The brain tissue in ischemic penumbra was determined the myeloperoxidase (MPO) activity by a spectrophotometer and expression of PPAR? was measured by Rt-PCR and Western blotting. Results Our findings showed that FNS group had significantly reduced infarct volume and brain edema, and improved neurological deficits compared with the control group, especially in 6h and 9h reperfusion subgroups(p<0.05). The expression levels of PPAR? increased gradually and the peak may be before and after 9h reperfusion, the 3h, 6h, 9h, 12h and 15h reperfusion subgroups were higher than each control group(p<0.05). The MPO activity of 6h, 12h and 15h reperfusion subgroups were higher than each control group(p<0.05). Conclusions The neuroprotective effects of FNS have been shown to prolong the therapeutic window in cerebral ischemia/reperfusion, which might be related to the PPAR? mediated-inflammation in penumbral region. PMID:26016630

  8. Comparison of in vitro preconditioning responses of isolated pig and rabbit cardiomyocytes: effects of a protein phosphatase inhibitor, fostriecin.

    PubMed

    Armstrong, S C; Kao, R; Gao, W; Shivell, L C; Downey, J M; Honkanen, R E; Ganote, C E

    1997-11-01

    Calcium tolerant pig and rabbit cardiomyocytes were isolated using retrograde aortic perfusion of nominally calcium-free collagenase. Preconditioning protocols used 1 or 3x10-min episodes of ischemic pelleting or pre-incubation with 100 micro M adenosine, followed by a 15-min post-incubation and 180-240-min ischemic pelleting. Control cells were incubated and washed in parallel with the experimental groups. Injury was assessed by determination of cell morphology, trypan blue permeability following osmotic swelling, lactate and HPLC analysis of adenine nucleotides. Preconditioned pig cardiomyocytes had a reduced rate of ischemic contracture, but protection occurred without conservation of ATP. Preconditioned rabbit cardiomyocytes were protected without significant changes in rates of ischemic contracture or ATP depletion. Incubation of ischemic cells with the protein phosphatase inhibitor, fostriecin, at PP2A-selective concentrations (0.1-10 micro M), mimicked preconditioning in both rabbit and pig cardiomyocytes. In rabbits, the KATP channel blocker, 5-hydroxydecanoate (5-HD), did not block preconditioning or fostriecin protection. In the pig, 5-HD blocked both preconditioning and fostriecin protection, with return of the rates of ischemic contracture to control. However, 5-HD was an effective blocker of protection only in early ischemia. Fostriecin mimicked preconditioning in the rabbit and the early responses of the preconditioned pig. Preconditioning appears associated with protein phosphorylation in both the rabbit and the pig, but major pathways leading to protection may differ in the two species. PMID:9405176

  9. Effects of ischemia and omeprazole preconditioning on functional recovery of isolated rat heart

    PubMed Central

    Jeremic, Nevena; Petkovic, Anica; Srejovic, Ivan; Zivkovic, Vladimir; Djuric, Dragan; Jakovljevic, Vladimir

    2015-01-01

    Objective The aim of this study was to compare protective effects of ischemic and potential protective effects of pharmacological preconditioning with omeprazole on isolated rat heart subjected to ischemia/reperfusion. Methods The hearts of male Wistar albino rats were excised and perfused on a Langendorff apparatus. In control group (CG) after stabilization period, hearts were subjected to global ischemia (perfusion was totally stopped) for 20 minutes and 30 minutes of reperfusion. Hearts of group II (IPC) were submitted to ischemic preconditioning lasting 5 minutes before 20 minutes of ischemia and 30 minutes of reperfusion. In third group (OPC) hearts first underwent preconditioning lasting 5 minutes with 100?M omeprazole, and then submitted 20 minutes of ischemia and 30 minutes of reperfusion. Results Administration of omeprazole before ischemia induction had protective effect on myocardium function recovery especially regarding to values of systolic left ventricular pressure and dp/dt max. Also our findings are that values of coronary flow did not change between OPC and IPC groups in last point of reperfusion. Conclusion Based on our results it seems that ischemic preconditioning could be used as first window of protection after ischemic injury especially because all investigated parameters showed continuous trend of recovery of myocardial function. On the other hand, preconditioning with omeprazole induced sudden trend of recovery with positive myocardium protection, although less effective than results obtained with ischemic preconditioning not withstand, we must consider that omeprazole may be used in many clinical circumstances where direct coronary clamping for ischemic preconditioning is not possible.

  10. Increased Hypoxic Tolerance by Chemical Inhibition of Oxidative Phosphorylation: “Chemical Preconditioning

    Microsoft Academic Search

    M. W. Riepe; F. Esclaire; K. Kasischke; S. Schreiber; H. Nakase; O. Kempski; A. C. Ludolph; U. Dirnagl; J. Hugon

    1997-01-01

    A short ischemic episode preceding sustained ischemia is known to increase tolerance against ischemic cell death. We report early-onset long-lasting neuroprotection against in vitro hypoxia by preceding selective chemical inhibition of oxidative phosphorylation: “chemical preconditioning.” The amplitude of CA1 population spikes (psap) in hippocampal slices prepared from control animals (control slices) was 31 ± 27% (mean ± SD) upon 45-min

  11. Angiogenic signal triggered by ischemic stress induces myocardial repair in rat during chronic infarction.

    PubMed

    Fukuda, Shoji; Kaga, Shigeaki; Sasaki, Hiroaki; Zhan, Lijun; Zhu, Li; Otani, Hajime; Kalfin, Reni; Das, Dipak K; Maulik, Nilanjana

    2004-04-01

    In the present study, we examined a novel method of stimulating myocardial angiogenesis through ischemic preconditioning (IP) in the form of in vivo four repetitive cycles of coronary artery occlusion each followed by reperfusion. Rats divided into 4 groups: Control+Sham surgery (CS), Control+ Left anterior descending coronary artery (LAD) occlusion (CMI), IP+ Sham surgery (IPS) and IP+LAD occlusion (IPMI). For cardiac function, rats were subjected to stress testing with dobutamine after 2, 4, 7, 14 and 21 operative days. Capillary density (CD) and arteriolar density (AD) were evaluated by immunohistochemistry. Western blot was performed to examine the expression pattern for VEGF and anti-death candidates, Bcl-2 and survivin. Blood flow and the extent of endothelial and cardiomyocyte cell death were examined. The protein/DNA array was performed to determine the status of various transcription factor related to stress signal. Left ventricular functional reserve was better preserved in IPMI compared to the CMI group. The infarct size and apoptotic cell death were reduced in IPMI group significantly. Left ventricular regional blood flow, perfused capillary density and AD increased significantly in the IPMI group. VEGF, Bcl-2 and survivin expression were increased in IPMI compared to CMI. VEGF mediated vascular permeability was controlled in the IPMI due to suppression of c-Src in the infarcted myocardium. Our study documented first time the ability of IP to induce angiogenesis in the infarcted myocardium along with the activation of several transcription factors such as Stat3, Pax-5, NF kappa B, TFIID, SP1 and reduction of VEGF mediated vascular permeability by inhibition of c-Src in IPMI group thereby reducing ischemic injury in rat MI model. PMID:15081314

  12. In Vitro Ischemic Tolerance Involves Upregulation of Glutamate Transport Partly Mediated by the TACE\\/ADAM17Tumor Necrosis Factor  Pathway

    Microsoft Academic Search

    Cristina Romera; Olivia Hurtado; Sofia H. Botella; Ignacio Lizasoain; Antonio Cardenas; Paz Fernandez-Tome; Juan C. Leza; Pedro Lorenzo; Maria A. Moro

    2004-01-01

    A short ischemic event (ischemic preconditioning (IPC)) can result in a subsequent resistance to severe ischemic injury (ischemic tolerance). Although tumor necrosis factor- (TNF-) contributes to the brain damage found after cerebral ischemia, its expression and neuroprotective role in models of IPC have also been described. Regarding the role of TNF- convertase (TACE\\/ADAM17), we have recently shown its upregulation in

  13. Endothelial progenitor cells from human dental pulp-derived iPS cells as a therapeutic target for ischemic vascular diseases.

    PubMed

    Yoo, Chae Hwa; Na, Hee-Jun; Lee, Dong-Seol; Heo, Soon Chul; An, Yuri; Cha, Junghwa; Choi, Chulhee; Kim, Jae Ho; Park, Joo-Cheol; Cho, Yee Sook

    2013-11-01

    Human dental pulp cells (hDPCs) are a valuable source for the generation of patient-specific human induced pluripotent stem cells (hiPSCs). An advanced strategy for the safe and efficient reprogramming of hDPCs and subsequent lineage-specific differentiation is a critical step toward clinical application. In present research, we successfully generated hDPC-iPSCs using only two non-oncogenic factors: Oct4 and Sox2 (2F hDPC-hiPSCs) and evaluated the feasibility of hDPC-iPSCs as substrates for endothelial progenitor cells (EPCs), contributing to EPC-based therapies. Under conventional differentiation conditions, 2F hDPC-hiPSCs showed higher differentiation efficiency, compared to hiPSCs from other cell types, into multipotent CD34(+) EPCs (2F-hEPCs) capable to differentiate into functional endothelial and smooth muscle cells. The angiogenic and neovasculogenic activities of 2F-hEPCs were confirmed using a Matrigel plug assay in mice. In addition, the therapeutic effects of 2F-hEPC transplantation were confirmed in mouse models of hind-limb ischemia and myocardial infarction. Importantly, 2F-EPCs effectively integrated into newly formed vascular structures and enhanced neovascularization via likely both direct and indirect paracrine mechanisms. 2F hDPC-hiPSCs have a robust capability for the generation of angiogenic and vasculogenic EPCs, representing a strategy for patient-specific EPC therapies and disease modeling, particularly for ischemic vascular diseases. PMID:23896001

  14. Immune mechanisms in cerebral ischemic tolerance

    PubMed Central

    Garcia-Bonilla, Lidia; Benakis, Corinne; Moore, Jamie; Iadecola, Costantino; Anrather, Josef

    2014-01-01

    Stressor-induced tolerance is a central mechanism in the response of bacteria, plants, and animals to potentially harmful environmental challenges. This response is characterized by immediate changes in cellular metabolism and by the delayed transcriptional activation or inhibition of genetic programs that are not generally stressor specific (cross-tolerance). These programs are aimed at countering the deleterious effects of the stressor. While induction of this response (preconditioning) can be established at the cellular level, activation of systemic networks is essential for the protection to occur throughout the organs of the body. This is best signified by the phenomenon of remote ischemic preconditioning, whereby application of ischemic stress to one tissue or organ induces ischemic tolerance (IT) in remote organs through humoral, cellular and neural signaling. The immune system is an essential component in cerebral IT acting simultaneously both as mediator and target. This dichotomy is based on the fact that activation of inflammatory pathways is necessary to establish IT and that IT can be, in part, attributed to a subdued immune activation after index ischemia. Here we describe the components of the immune system required for induction of IT and review the mechanisms by which a reprogrammed immune response contributes to the neuroprotection observed after preconditioning. Learning how local and systemic immune factors participate in endogenous neuroprotection could lead to the development of new stroke therapies. PMID:24624056

  15. The divergent roles of autophagy in ischemia and preconditioning

    PubMed Central

    Sheng, Rui; Qin, Zheng-hong

    2015-01-01

    Autophagy is an evolutionarily conserved and lysosome-dependent process for degrading and recycling cellular constituents. Autophagy is activated following an ischemic insult or preconditioning, but it may exert dual roles in cell death or survival during these two processes. Preconditioning or lethal ischemia may trigger autophagy via multiple signaling pathways involving endoplasmic reticulum (ER) stress, AMPK/TSC/mTOR, Beclin 1/BNIP3/SPK2, and FoxO/NF-?B transcription factors, etc. Autophagy then interacts with apoptotic and necrotic signaling pathways to regulate cell death. Autophagy may also maintain cell function by removing protein aggregates or damaged mitochondria. To date, the dual roles of autophagy in ischemia and preconditioning have not been fully clarified. The purpose of the present review is to summarize the recent progress in the mechanisms underlying autophagy activation during ischemia and preconditioning. A better understanding of the dual effects of autophagy in ischemia and preconditioning could help to develop new strategies for the preventive treatment of ischemia. PMID:25832421

  16. PRECONDITIONING BLOCK TOEPLITZ MATRICES

    Microsoft Academic Search

    THOMAS K. HUCKLE; DIMITRIOS NOUTSOS

    2007-01-01

    We investigate the spectral behavior of preconditioned block Toeplitz matrices with small non- Toeplitz blocks. These matrices have a quite different behavior than scalar or mulitlevel Toeplitz matrices. Based on the connection between Toeplitz and Hankel matrices we derive some negative results on eigenvalue clustering for ill-conditioned block Toeplitz matrices. Furthermore, we identify Block Toeplitz matrices that are easy to

  17. Remote preconditioning by infrarenal aortic occlusion is operative via y1-opioid receptors and free radicals in vivo in the rat heart

    Microsoft Academic Search

    Christof Weinbrenner; Falk Schulze; Ruth H. Strasser

    Background: Ischemic preconditioning (PC) is a powerful mechanism in reducing infarct size of the heart. Protection can be performed either by an ischemic stimulus of the heart itself or by ischemia of an organ distant to the heart (remote PC). We have previously shown that remote PC by infrarenal occlusion of the aorta (IOA) in the rat is as powerful

  18. Interleukin-6 mediates exercise preconditioning against myocardial ischemia reperfusion injury.

    PubMed

    McGinnis, Graham Ripley; Ballmann, Christopher; Peters, Bridget; Nanayakkara, Gayani; Roberts, Michael; Amin, Rajesh; Quindry, John C

    2015-06-01

    Interleukin-6 (IL-6) is a pleiotropic cytokine that protects against cardiac ischemia-reperfusion (I/R) injury following pharmacological and ischemic preconditioning (IPC), but the affiliated role in exercise preconditioning is unknown. Our study purpose was to characterize exercise-induced IL-6 cardiac signaling (aim 1) and evaluate myocardial preconditioning (aim 2). In aim 1, C57 and IL-6(-/-) mice underwent 3 days of treadmill exercise for 60 min/day at 18 m/min. Serum, gastrocnemius, and heart were collected preexercise, immediately postxercise, and 30 and 60 min following the final exercise session and analyzed for indexes of IL-6 signaling. For aim 2, a separate cohort of exercise-preconditioned (C57 EX and IL-6(-/-) EX) and sedentary (C57 SED and IL-6(-/-) SED) mice received surgical I/R injury (30 min I, 120 min R) or a time-matched sham operation. Ischemic and perfused tissues were examined for necrosis, apoptosis, and autophagy. In aim 1, serum IL-6 and IL-6 receptor (IL-6R), gastrocnemius, and myocardial IL-6R were increased following exercise in C57 mice only. Phosphorylated (p) signal transducer and activator of transcription 3 was increased in gastrocnemius and heart in C57 and IL-6(-/-) mice postexercise, whereas myocardial iNOS and cyclooxygenase-2 were unchanged in the exercised myocardium. Exercise protected C57 EX mice against I/R-induced arrhythmias and necrosis, whereas arrhythmia score and infarct outcomes were higher in C57 SED, IL-6(-/-) SED, and IL-6(-/-) EX mice compared with SH. C57 EX mice expressed increased p-p44/42 MAPK (Thr(202)/Tyr(204)) and p-p38 MAPK (Thr(180)/Tyr(182)) compared with IL-6(-/-) EX mice, suggesting pathway involvement in exercise preconditioning. Findings indicate exercise exerts cardioprotection via IL-6 and strongly implicates protective signaling originating from the exercised skeletal muscle. PMID:25820396

  19. Endothelial preconditioning by transient oxidative stress reduces inflammatory responses of cultured endothelial cells to TNF-a

    Microsoft Academic Search

    STEFAN ZAHLER; CHRISTIAN KUPATT; BERNHARD F. BECKER

    Brief episodes of ischemia can render an organ resistant to subsequent severe ischemia. This 'ischemic preconditioning' is ascribed to vari- ous mechanisms, including oxidative stress. We in- vestigated whether preconditioning exists on an en- dothelial level. Human umbilical vein endothelial cells (HUVECs) were transiently confronted with oxidative stress (1 mM H2O2, 5 min). Adhesion molecules ICAM-1 and E-selectin and release

  20. Hypoxic preconditioning induces stroke tolerance in mice via a cascading HIF, sphingosine kinase, and CCL2 signaling pathway

    PubMed Central

    Wacker, Bradley K.; Perfater, Jennifer L.; Gidday, Jeffrey M.

    2012-01-01

    The induction of ischemic tolerance by preconditioning provides a platform to elucidate endogenous mechanisms of stroke protection. In these studies, we characterize the relationship between hypoxia-inducible factor (HIF), sphingosine kinase 2 (SphK2), and CCL2 in models of hypoxic or pharmacological preconditioning-induced ischemic tolerance. A genetics-based approach using SphK2- and CCL2-null mice showed both SphK2 and CCL2 to be necessary for the induction of ischemic tolerance following preconditioning with hypoxia, the hypoxia-mimetic cobalt chloride, or the sphingosine-1-phosphate (S1P) agonist FTY720. A pharmacologic approach confirmed the necessity of HIF signaling for all three preconditioning stimuli, and showed the SphK/S1P pathway to transduce tolerance via the S1P1 receptor. Additionally, our data suggest significant cross-talk between HIF and SphK2-produced S1P signaling, which together act to upregulate CCL2 expression. Overall, HIF, SphK, S1P, and CCL2 participate in a signaling cascade to induce the gene expression responsible for the stroke-tolerant phenotype established by hypoxic and FTY720 preconditioning. The identification of these common molecular mediators involved in signaling the genomic response to multiple preconditioning stimuli provides several targets for therapeutic manipulation. PMID:23043544

  1. Transient Ischemic Attack

    MedlinePLUS

    NINDS Transient Ischemic Attack Information Page Synonym(s): Mini Stroke Table of Contents (click to jump to sections) What is ... Trials Organizations Additional resources from MedlinePlus What is Transient Ischemic Attack? A transient ischemic attack (TIA) is ...

  2. Blood as the carrier of ischemic tolerance in rat brain.

    PubMed

    Bonova, Petra; Gottlieb, Miroslav

    2015-08-01

    This study provides clear evidence that the factor inducing tolerance to ischemia is transmitted via the circulating blood. By using the remote ischemia and the cross-circulation model, the tolerance to ischemia was transmitted from donor to recipient. For this study, the following experimental groups were designed: I, sham control group; II, group of tolerant hindlimb tourniquet-treated rats; III, positive control group; IV, control for cross-circulation influence; preconditioned animals: V, tolerant animals subjected to middle cerebral artery occlusion (MCAO); VI, tolerant animals cross-circulated with SHC, followed by MCAO; VII, SHC animals cross-circulated with tolerant animals and subsequently subjected to MCAO; VIII, tolerant animals cross-circulated with ischemic rats, followed by MCAO; IX, SHC animals cross-circulated with ischemic animals and subjected to MCAO; postconditioned animals: X, ischemic animals treated with a remote limb tourniquet; XI, ischemic animals cross-circulated with SHC control rats; and XII, ischemic animals cross-circulated with tolerant rats. Results confirmed that remote ischemia induced reduction of infarct volume in the preconditioned (V, 60%) as well as in the postconditioned group (X, 52%). Significant diminution was also observed in group XII (56.6%). In the preconditioned group, decreased infarct volume was detected in groups VI and VII (about 65%) and in group IX (about 50%). The greatest infarct reduction (84%) was induced by the presence of ischemic blood in a tolerant rat before ischemia induction. In summary, the factor inducing tolerance to ischemia is generated by remote ischemia and by ischemia itself; from the site of origin to the rest of the body, it is transported by the systemic blood circulation and can be transferred from animal to animal. The effect of conditioning with two different ischemic events (brain and hindlimb ischemia) led to a cumulative, stronger tolerance response. © 2015 Wiley Periodicals, Inc. PMID:25787695

  3. Comparison of In Vitro Preconditioning Responses of Isolated Pig and Rabbit Cardiomyocytes: Effects of a Protein Phosphatase Inhibitor, Fostriecin

    Microsoft Academic Search

    S. C. Armstrong; R. Kao; W. Gao; L. C. Shivell; J. M. Downey; R. E. Honkanen; C. E. Ganote

    1997-01-01

    Calcium tolerant pig and rabbit cardiomyocytes were isolated using retrograde aortic perfusion of nominally calcium-free collagenase. Preconditioning protocols used 1 or 3×10-min episodes of ischemic pelleting or pre-incubation with 100?madenosine, followed by a 15-min post-incubation and 180–240-min ischemic pelleting. Control cells were incubated and washed in parallel with the experimental groups. Injury was assessed by determination of cell morphology, trypan

  4. Clinical application of preconditioning and postconditioning to achieve neuroprotection.

    PubMed

    Dezfulian, Cameron; Garrett, Matthew; Gonzalez, Nestor R

    2013-02-01

    Ischemic conditioning is a form of endogenous protection induced by transient, subcritical ischemia in a tissue. Organs with high sensitivity to ischemia, such as the heart, the brain, and spinal cord, represent the most critical and potentially promising targets for potential therapeutic applications of ischemic conditioning. Numerous preclinical investigations have systematically studied the molecular pathways and potential benefits of both pre- and postconditioning with promising results. The purpose of this review is to summarize the present knowledge on cerebral pre- and postconditioning, with an emphasis in the clinical application of these forms of neuroprotection. A systematic MEDLINE search for the terms preconditioning and postconditioning was performed. Publications related to the nervous system and to human applications were selected and analyzed. Pre- and postconditioning appear to provide similar levels of neuroprotection. The preconditioning window of benefit can be subdivided into early and late effects, depending on whether the effect appears immediately after the sublethal stress or with a delay of days. In general, early effects have been associated posttranslational modification of critical proteins (membrane receptors, mitochondrial respiratory chain) while late effects are the result of gene up- or downregulation. Transient ischemic attacks appear to represent a form of clinically relevant preconditioning by inducing ischemic tolerance in the brain and reducing the severity of subsequent strokes. Remote forms of ischemic pre- and postconditioning have been more commonly used in clinical studies, as the remote application reduces the risk of injuring the target tissue for which protection is pursued. Limb transient ischemia is the preferred method of induction of remote conditioning with evidence supporting its safety. Clinical studies in a variety of populations at risk of central nervous damage including carotid disease, cervical myelopathy, and subarachnoid hemorrhage have shown improvement in surrogate markers of injury. Promising preclinical and early clinical studies noting improvement in surrogate markers of central nervous injury after the use of remote pre- and postconditioning treatments demand follow-up systematic investigations to address effectiveness. Challenges in the application of these techniques to pressing clinical cerebrovascular disease ought to be overcome through careful, well-designed, translational investigations. PMID:24323188

  5. Outline o IP Addressing

    E-print Network

    Biagioni, Edoardo S.

    Outline o IP Addressing o IP forwarding o ARP o IP header 1 #12; IP addressing o IP address can be logically split into two (identifier) - see below for details of final delivery o static subdivision - address classes o

  6. The role of the rat sarcoplasmic reticulum Ca 2+ ATPase promoter in myocardial ischemia-preconditioning

    Microsoft Academic Search

    Nengfeng Zhang; Baohua Zhu

    2010-01-01

    Intracellular calcium ion concentration ([Ca2+]i) is a key regulator of ischemia–reperfusion injury (IRI) and ischemic preconditioning (IPC), with myocardial sarcoplasmic\\u000a reticulum Ca2+-ATPase (SERCA2a) acting as the major regulatory protein in the control of [Ca2+]i. In this study, we examined the effect of the SERCA2a promoter in IRI and IPC. The SERCA2a promoter fragment was acquired\\u000a using PCR and molecular cloning

  7. Human embryonic stem cell neural differentiation and enhanced cell survival promoted by hypoxic preconditioning

    Microsoft Academic Search

    K R Francis; L Wei

    2010-01-01

    Transplantation of neural progenitors derived from human embryonic stem cells (hESCs) provides a potential therapy for ischemic stroke. However, poor graft survival within the host environment has hampered the benefits and applications of cell-based therapies. The present investigation tested a preconditioning strategy to enhance hESC tolerance, thereby improving graft survival and the therapeutic potential of hESC transplantation. UC06 hESCs underwent

  8. Mobile IPMobile IP Mobile IPMobile IP

    E-print Network

    Yeom, Ikjun

    Mobile IPMobile IP #12;2 Mobile IPMobile IP · How do we support mobile users whose point of attachment to the network changes dynamically? #12;3 Mobile IPMobile IP · The goal of Mobile IP is to allow connectivity automatically, despite the change. · While Mobile IP can work with wired connections, where you

  9. SIP Server VoIP UA IP

    E-print Network

    SIP Server UA UA IP VoIP UA IP 1 1 Transport Layer Security (TLS) SIP server TLS Client TLS TLS Client VoIP SRTP SIP server TLS Client TLS SRTP .2> Skype (Skype Trunk) skype server skype ( Skype Client ) skype 20 20 VoIP Option

  10. Mobile IP Using Private IP Addresses

    Microsoft Academic Search

    Toshihiko Kato; Akira Idoue; Hidetoshi Yokota

    2001-01-01

    The mobile IP data communication is widely spreading. Accordingly, it is pointed out that the number of IP addresses in IPv4 will be short if every mobile terminal has its IP address. In order to solve this address starvation problem, we propose an approach to realize mobile IP protocol by assigning a private IP address to a mobile terminal. It

  11. TIA (Transient Ischemic Attack)

    MedlinePLUS

    TIA (Transient Ischemic Attack) Updated:Jul 1,2015 Excerpted from “ Why Rush? ”, Stroke Connection January/February 2009 (Science update October 2012) While transient ischemic attack (TIA) is often labeled “mini-stroke,” ...

  12. Transient ischemic attack

    MedlinePLUS

    A transient ischemic attack (TIA) occurs when blood flow to a part of the brain stops for a brief ... prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from ...

  13. 40 CFR 1065.518 - Engine preconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...emission testing: (1) Cold-start transient cycle. Precondition the engine by running at least one hot-start transient cycle. We will precondition your engine by running two hot-start transient cycles. Immediately after...

  14. Adenosine A1 receptor activation modulates N-methyl-d-aspartate (NMDA) preconditioning phenotype in the brain.

    PubMed

    Constantino, Leandra C; Pamplona, Fabrício A; Matheus, Filipe C; Ludka, Fabiana K; Gomez-Soler, Maricel; Ciruela, Francisco; Boeck, Carina R; Prediger, Rui D; Tasca, Carla I

    2015-04-01

    N-methyl-d-aspartate (NMDA) preconditioning is induced by subtoxic doses of NMDA and it promotes a transient state of resistance against subsequent lethal insults. Interestingly, this mechanism of neuroprotection depends on adenosine A1 receptors (A1R), since blockade of A1R precludes this phenomenon. In this study we evaluated the consequences of NMDA preconditioning on the hippocampal A1R biology (i.e. expression, binding properties and functionality). Accordingly, we measured A1R expression in NMDA preconditioned mice (75mg/kg, i.p.; 24h) and showed that neither the total amount of receptor, nor the A1R levels in the synaptic fraction was altered. In addition, the A1R binding affinity to the antagonist [(3)H] DPCPX was slightly increased in total membrane extracts of hippocampus from preconditioned mice. Next, we evaluated the impact of NMDA preconditioning on A1R functioning by measuring the A1R-mediated regulation of glutamate uptake into hippocampal slices and on behavioral responses in the open field and hot plate tests. NMDA preconditioning increased glutamate uptake into hippocampal slices without altering the expression of glutamate transporter GLT-1. Interestingly, NMDA preconditioning also induced antinociception in the hot plate test and both effects were reversed by post-activation of A1R with the agonist CCPA (0.2mg/kg, i.p.). NMDA preconditioning or A1R modulation did not alter locomotor activity in the open field. Overall, the results described herein provide new evidence that post-activation of A1R modulates NMDA preconditioning-mediated responses, pointing to the importance of the cross-talk between glutamatergic and adenosinergic systems to neuroprotection. PMID:25557798

  15. Preconditioning with +Gz acceleration (head-to-foot inertial load) produces neuroprotection against transient focal cerebral ischemia in rats.

    PubMed

    Sang, Hanfei; Li, Jinsheng; Liu, Junle; Wang, Zhou; Huo, Tingting; Sun, Jing; Xiong, Lize

    2008-11-01

    Ischemic preconditioning is considered to be the most robust endogenous neuroprotectant. However, the conventional ischemic preconditioning protocol is both invasive and impractical to apply. The aim of the present study was to evaluate whether preconditioning with +Gz centrifuge acceleration (head-to-foot inertial load) which could induce brief episodes of sublethal ischemia in brain had neuroprotection against focal cerebral ischemic injury. A total of 85 male Sprague-Dawley rats were randomly assigned to five groups (n = 17 in each). The 2 Gz, 4 Gz, 6 Gz and 8 Gz groups were subjected to 3 min exposures at +2 Gz, +4 Gz, +6 Gz and +8 Gz, respectively for consecutive three times in animal centrifuge, with a 30-min rest period between each centrifuge run. The control group had no exposure to +Gz acceleration. Twenty-four hours after the last pretreatment, 12 rats in each groups were subjected to focal cerebral ischemia for 120 min and the other five rats in each group were sacrificed to measure the expression of heat shock protein 70(HSP70) in hippocampus by Western blot analysis. The results indicated that the 6 Gz and 8 Gz groups showed smaller infarct volume and lower neurologic deficit scores than the control group. The expression of HSP70 was significantly increased in 6 Gz and 8 Gz groups than those in the control group. Therefore, preconditioning with +Gz acceleration produced delayed neuroprotection against focal cerebral ischemia and that the neuroprotection may be related to the induction of HSP70. PMID:18778750

  16. Preconditioning rabbit cardiomyocytes: role of pH, vacuolar proton ATPase, and apoptosis.

    PubMed Central

    Gottlieb, R A; Gruol, D L; Zhu, J Y; Engler, R L

    1996-01-01

    Ischemic preconditioning signals through protein kinase C (PKC) to protect against myocardial infarction. This protection is characterized by diminished intracellular acidification. Acidification is also a feature of apoptosis, and several agents act to prevent apoptosis by preventing acidification through activation of ion channels and pumps to promote cytoplasmic alkalinization. We characterized metabolic inhibition, recovery, and preconditioning through a PKC-dependent pathway in cardiomyocytes isolated from adult rabbit hearts. Preconditioning reduced loss of viability assessed by morphology and reduced DNA nicking. Blockade of the vacuolar proton ATPase (VPATPase) prevented the effect of preconditioning to reduce metabolic inhibition-induced acidosis, loss of viability, and DNA nicking. The beneficial effect of Na+/H+ exchange inhibition, which is thought to be effective through reduced intracellular Na+ and Ca++, was also abrogated by VPATPase blockade, suggesting that acidification even in the absence of Na+/H+ exchange may lead to cell death. We conclude that a target of PKC in mediating preconditioning is activation of the VPATPase with resultant attenuation of intracellular acidification during metabolic inhibition. Inhibition of the "death protease," interleukin-1-beta converting enzyme or related enzymes, also protected against the injury that followed metabolic inhibition. This observation, coupled with the detection of DNA nicking in cells subjected to metabolic inhibition, suggests that apoptotic cell death may be preventable in this model of ischemia/reperfusion injury. PMID:8636421

  17. Bradykinin preconditioning affects the number of degenerated neurons and the level of antioxidant enzymes in spinal cord ischemia in rabbits.

    PubMed

    Mechírová, Eva; Danielisová, Viera; Domoráková, Iveta; Danková, Marianna; Stebnický, Milan; Mi?ková, Helena; Burda, Jozef

    2014-01-01

    Bradykinin preconditioning has been used for acquisition of tolerance after spinal cord ischemia. Rabbits were preconditioned intraperitoneally with bradykinin 48 h prior to 20 min of abdominal aorta ligation followed by 24 and 48 h of reperfusion. The activities of SOD and catalase were measured and Fluoro Jade B (FJB)-positive degenerated neurons were evaluated. The outcomes of Tarlov scoring system used to assess neurological functions showed significant improvement in bradykinin groups compared to the ischemic group. The number of FJB-positive degenerated neurons was decreased in ventral horns of both bradykinin groups. Significantly decreased activities of total SOD and mitochondrial Mn-SOD were also detected in both bradykinin groups versus ischemic group while CuZn-SOD and catalase activities were significantly decreased only in the bradykinin group after 24h of reperfusion versus ischemic group. These findings suggest that one of the possibilities of the neuroprotective effect of delayed bradykinin preconditioning against spinal cord ischemic injury could be realized by mitochondrial protection and decreased synthesis of Mn-SOD as well as by promotion of neuronal survival. PMID:23981244

  18. Cortical spreading depression-induced preconditioning in mouse neocortex is lamina specific.

    PubMed

    Gniel, Helen M; Martin, Rosemary L

    2013-06-01

    Cortical spreading depression (CSD) is able to confer neuroprotection when delivered at least 1 day in advance of an ischemic event. However, its ability to confer neuroprotection in a more immediate time frame has not previously been investigated. Here we have used mouse neocortical brain slices to study the effects of repeated episodes of CSD in layer V and layer II/III pyramidal neurons. In layer V, CSD evoked at 15-min intervals caused successively smaller membrane depolarizations and increases in intracellular calcium compared with the response to the first CSD. With an inter-CSD interval of 30 min this preconditioning effect was much less marked, indicating that preconditioning lasts between 15 and 30 min. A single episode of CSD also provided a degree of protection in oxygen-glucose deprivation (OGD) by significantly lengthening the time a cell could withstand OGD before anoxic depolarization occurred. In layer II/III pyramidal neurons no preconditioning by CSD on subsequent episodes of CSD was observed, demonstrating that the response of pyramidal neurons to repeated CSD is lamina specific. The A1 receptor antagonist 8-cyclopentyl theophylline (8-CPT) reduced the layer V preconditioning in a concentration-related manner. Inhibition of extracellular formation of adenosine by blocking ecto-5'-nucleotidase with ?,?-methyleneadenosine 5'-diphosphate prevented preconditioning in most but not all cells. Block of equilibrative nucleoside transporters 1 and 2 with dipyramidole alone or in combination with 6-[(4-nitrobenzyl)thio]-9-?-d-ribofuranosylpurine also prevented preconditioning in some but not all cells. These data provide evidence that rapid preconditioning of one CSD by another is primarily mediated by adenosine. PMID:23515796

  19. Effects of diabetes on myocardial infarct size and cardioprotection by preconditioning and postconditioning

    PubMed Central

    2012-01-01

    In spite of the current optimal therapy, the mortality of patients with ischemic heart disease (IHD) remains high, particularly in cases with diabetes mellitus (DM) as a co-morbidity. Myocardial infarct size is a major determinant of prognosis in IHD patients, and development of a novel strategy to limit infarction is of great clinical importance. Ischemic preconditioning (PC), postconditioning (PostC) and their mimetic agents have been shown to reduce infarct size in experiments using healthy animals. However, a variety of pharmacological agents have failed to demonstrate infarct size limitation in clinical trials. One of the possible reasons for the discrepancy between the results of animal experiments and clinical trials is that co-morbidities, including DM, modified myocardial responses to ischemia/reperfusion and to cardioprotective agents. Here we summarize observations of the effects of DM on myocardial infarct size and ischemic PC and PostC and discuss perspectives for protection of DM hearts. PMID:22694800

  20. Preconditioning for temporal video superresolution

    E-print Network

    Cooperstock, Jeremy R.

    Preconditioning for temporal video superresolution St´ephane Pelletier and Jeremy R. Cooperstock.pelletier@mail.mcgill.ca jer@cim.mcgill.ca Abstract Temporal superresolution produces a video sequence of high temporal resolution (HTR), i.e. frame rate, from a set of video sequences of low tem- poral resolution (LTR). A method

  1. LPS-Induced Delayed Preconditioning Is Mediated by Hsp90 and Involves the Heat Shock Response in Mouse Kidney

    PubMed Central

    Kaucsár, Tamás; Bodor, Csaba; Godó, Mária; Szalay, Csaba; Révész, Csaba; Németh, Zalán; Mózes, Miklós; Szénási, Gábor; Rosivall, László; S?ti, Csaba; Hamar, Péter

    2014-01-01

    Introduction We and others demonstrated previously that preconditioning with endotoxin (LPS) protected from a subsequent lethal LPS challenge or from renal ischemia-reperfusion injury (IRI). LPS is effective in evoking the heat shock response, an ancient and essential cellular defense mechanism, which plays a role in resistance to, and recovery from diseases. Here, by using the pharmacological Hsp90 inhibitor novobiocin (NB), we investigated the role of Hsp90 and the heat shock response in LPS-induced delayed renal preconditioning. Methods Male C57BL/6 mice were treated with preconditioning (P: 2 mg/kg, ip.) and subsequent lethal (L: 10 mg/kg, ip.) doses of LPS alone or in combination with NB (100 mg/kg, ip.). Controls received saline (C) or NB. Results Preconditioning LPS conferred protection from a subsequent lethal LPS treatment. Importantly, the protective effect of LPS preconditioning was completely abolished by a concomitant treatment with NB. LPS induced a marked heat shock protein increase as demonstrated by Western blots of Hsp70 and Hsp90. NB alone also stimulated Hsp70 and Hsp90 mRNA but not protein expression. However, Hsp70 and Hsp90 protein induction in LPS-treated mice was abolished by a concomitant NB treatment, demonstrating a NB-induced impairment of the heat shock response to LPS preconditioning. Conclusion LPS-induced heat shock protein induction and tolerance to a subsequent lethal LPS treatment was prevented by the Hsp90 inhibitor, novobiocin. Our findings demonstrate a critical role of Hsp90 in LPS signaling, and a potential involvement of the heat shock response in LPS-induced preconditioning. PMID:24646925

  2. Angina-Induced Protection Against Myocardial Infarction in Adult and Elderly Patients: A Loss of Preconditioning Mechanism in the Aging Heart?

    Microsoft Academic Search

    Pasquale Abete; Nicola Ferrara; Francesco Cacciatore; Alfredo Madrid; Sabatino Bianco; Claudio Calabrese; Claudio Napoli; Paola Scognamiglio; Ornella Bollella; Angelo Cioppa; Giancarlo Longobardi; Franco Rengo

    1997-01-01

    Objectives. The present study examined whether angina 48 h before myocardial infarction provides protection in adult and elderly patients.Background. The mortality rate for coronary artery disease is greater in elderly than in young patients. In experimental studies, ischemic preconditioning affords an endogenous form of protection against ischemia–reperfusion injury in adult but not in senescent hearts. Angina before myocardial infarction, a

  3. The natural olive constituent oleuropein induces nutritional cardioprotection in normal and cholesterol-fed rabbits: comparison with preconditioning.

    PubMed

    Andreadou, Ioanna; Benaki, Dimitra; Efentakis, Panagiotis; Bibli, Sofia-Iris; Milioni, Alkistis-Ioanna; Papachristodoulou, Anastasia; Zoga, Anastasia; Skaltsounis, Alexios-Leandros; Mikros, Emmanuel; Iliodromitis, Efstathios K

    2015-06-01

    Ischemic preconditioning, which is mediated by cell signaling molecules, protects the heart from ischemia-reperfusion injury by limiting the infarct size. Oleuropein, the main polyphenolic constituent of olives, reduced the infarct size in normal and cholesterol-fed rabbits when it was administered at a nutritional dose. The aim of the present study was to compare the effects of oleuropein and preconditioning in terms of the cell signaling and metabolism pathways underlying myocardial protection. Rabbits were randomly divided into six groups: the control group received 5?% dextrose for six weeks, the preconditioning group was subjected to two cycles of preconditioning with 5?min ischemia/10?min reperfusion, the O6 group was treated with oleuropein for six weeks, the Chol group was fed a cholesterol-enriched diet and 5?% dextrose for six weeks, and the CholO6 and CholO3 groups were treated with cholesterol and oleuropein for six and three weeks, respectively; oleuropein was dissolved in 5?% dextrose solution and was administered orally at a dose of 20?mg?×?kg(-1)?×?day(-1). All animals were subsequently subjected to 30?min myocardial ischemia followed by 10?min of reperfusion. At that time, myocardial biopsies were taken from the ischemic areas for the assessment of oxidative and nitrosative stress biomarkers (malondialdehyde and nitrotyrosine), and determination of phosphorylation of signaling molecules involved in the mechanism of preconditioning (PI3K, Akt, eNOS, AMPK, STAT3). The tissue extracts NMR metabolic profile was recorded and further analyzed by multivariate statistics. Oxidative biomarkers were significantly reduced in the O6, CholO6, and CholO3 groups compared to the control, preconditioning, and Chol groups. Considering the underlying signaling cascade, the phosphorylation of PI3K, Akt, eNOS, AMPK, and STAT-3 was significantly higher in the preconditioning and all oleuropein-treated groups compared to the control and Chol groups. The NMR-based metabonomic study, performed through the analysis of spectroscopic data, depicted differences in the metabolome of the various groups with significant alterations in purine metabolism. In conclusion, the addition of oleuropein to a normal or hypercholesterolemic diet results in a preconditioning-like intracellular effect, eliminating the deleterious consequences of ischemia and hypercholesterolemia, followed by a decrease of oxidative stress biomarkers. This effect is exerted through inducing preconditioning-involved signaling transduction. Nutritional preconditioning may support the low cardiovascular morbidity and mortality associated with the consumption of olive products. PMID:25473920

  4. Ischemic tolerance modulates TRAIL expression and its receptors and generates a neuroprotected phenotype.

    PubMed

    Cantarella, G; Pignataro, G; Di Benedetto, G; Anzilotti, S; Vinciguerra, A; Cuomo, O; Di Renzo, G F; Parenti, C; Annunziato, L; Bernardini, R

    2014-01-01

    TNF-related apoptosis inducing ligand (TRAIL), a member of the TNF superfamily released by microglia, appears to be involved in the induction of apoptosis following focal brain ischemia. Indeed, brain ischemia is associated with progressive enlargement of damaged areas and prominent inflammation. As ischemic preconditioning reduces inflammatory response to brain ischemia and ameliorates brain damage, the purpose of the present study was to evaluate the role of TRAIL and its receptors in stroke and ischemic preconditioning and to propose, by modulating TRAIL pathway, a new therapeutic strategy in stroke. In order to achieve this aim a rat model of harmful focal ischemia, obtained by subjecting animals to 100 min of transient occlusion of middle cerebral artery followed by 24 h of reperfusion and a rat model of ischemic preconditioning in which the harmful ischemia was preceded by 30 mins of tMCAO, which represents the preconditioning protective stimulus, were used. Results show that the neuroprotection elicited by ischemic preconditioning occurs through both upregulation of TRAIL decoy receptors and downregulation of TRAIL itself and of its death receptors. As a counterproof, immunoneutralization of TRAIL in tMCAO animals resulted in significant restraint of tissue damage and in a marked functional recovery. Our data shed new light on the mechanisms that propagate ongoing neuronal damage after ischemia in the adult mammalian brain and provide new molecular targets for therapeutic intervention. Strategies aimed to repress the death-inducing ligands TRAIL, to antagonize the death receptors, or to activate the decoy receptors open new perspectives for the treatment of stroke. PMID:25032854

  5. Ischemic tolerance modulates TRAIL expression and its receptors and generates a neuroprotected phenotype

    PubMed Central

    Cantarella, G; Pignataro, G; Di Benedetto, G; Anzilotti, S; Vinciguerra, A; Cuomo, O; Di Renzo, G F; Parenti, C; Annunziato, L; Bernardini, R

    2014-01-01

    TNF-related apoptosis inducing ligand (TRAIL), a member of the TNF superfamily released by microglia, appears to be involved in the induction of apoptosis following focal brain ischemia. Indeed, brain ischemia is associated with progressive enlargement of damaged areas and prominent inflammation. As ischemic preconditioning reduces inflammatory response to brain ischemia and ameliorates brain damage, the purpose of the present study was to evaluate the role of TRAIL and its receptors in stroke and ischemic preconditioning and to propose, by modulating TRAIL pathway, a new therapeutic strategy in stroke. In order to achieve this aim a rat model of harmful focal ischemia, obtained by subjecting animals to 100?min of transient occlusion of middle cerebral artery followed by 24?h of reperfusion and a rat model of ischemic preconditioning in which the harmful ischemia was preceded by 30?mins of tMCAO, which represents the preconditioning protective stimulus, were used. Results show that the neuroprotection elicited by ischemic preconditioning occurs through both upregulation of TRAIL decoy receptors and downregulation of TRAIL itself and of its death receptors. As a counterproof, immunoneutralization of TRAIL in tMCAO animals resulted in significant restraint of tissue damage and in a marked functional recovery. Our data shed new light on the mechanisms that propagate ongoing neuronal damage after ischemia in the adult mammalian brain and provide new molecular targets for therapeutic intervention. Strategies aimed to repress the death-inducing ligands TRAIL, to antagonize the death receptors, or to activate the decoy receptors open new perspectives for the treatment of stroke. PMID:25032854

  6. Signal mechanism activated by erythropoietin preconditioning and remote renal preconditioning-induced cardioprotection

    Microsoft Academic Search

    Vishal Diwan; Ravi Kant; Amteshwar Singh Jaggi; Nirmal Singh; Dhandeep Singh

    2008-01-01

    It has been recently reported that release of erythropoietin could mediate the cardioprotective effects of remote renal preconditioning.\\u000a However, the mechanism of erythropoietin-mediated cardioprotection in remote preconditioning is still unexplored. Therefore,\\u000a the present study was designed to investigate the possible signal transduction pathway of erythropoietin-mediated cardioprotection\\u000a in remote preconditioning in rats. Remote renal preconditioning was performed by four episodes of

  7. Weighted Graph Based Ordering Techniques for Preconditioned Conjugate Gradient Methods

    E-print Network

    Waterloo, University of

    Weighted Graph Based Ordering Techniques for Preconditioned Conjugate Gradient Methods Simon S: Preconditioned conjugate gradient, preconditioner, matrixordering, weighted graph Running Title: Weighted Graph's University, Kingston, Ontario. 1 #12;2 Weighted Graph Ordering for PCG Methods 1 Introduction Preconditioned

  8. Pharmacologic therapy that simulates conditioning for cardiac ischemic/reperfusion injury.

    PubMed

    Sivaraman, Vivek; Yellon, Derek M

    2014-01-01

    Cardiovascular disease remains a leading cause of deaths due to noncommunicable diseases, of which ischemic heart disease forms a large percentage. The main therapeutic strategy to treat ischemic heart disease is reperfusion that could either be medical or surgical. However, reperfusion following ischemia is known to increase the infarct size further. Newer strategies such as ischemic preconditioning (IPC), ischemic postconditioning, and remote IPC have been shown to condition the myocardium to ischemia-reperfusion injury and thus reduce the final infarct size. Research over the past 3 decades has deepened our understanding of cellular and subcellular pathways that mediate ischemia-reperfusion injury. This in turn has resulted in the development of several pharmacological agents that act as conditioning agents, which reduce the final myocardial infarct size following ischemia-reperfusion. This review discusses many of these agents, their mechanisms of action, and the animal and clinical evidence behind them. PMID:24038018

  9. Management of Preconditioned Calves and Impacts of Preconditioning.

    PubMed

    Hilton, W Mark

    2015-07-01

    When studying the practice of preconditioning (PC) calves, many factors need to be examined to determine if cow-calf producers should make this investment. Factors such as average daily gain, feed efficiency, available labor, length of the PC period, genetics, and marketing options must be analyzed. The health sales price advantage is an additional benefit in producing and selling PC calves but not the sole determinant of PC's financially feasibility. Studies show that a substantial advantage of PC is the selling of additional pounds at a cost of gain well below the marginal return of producing those additional pounds. PMID:26139187

  10. Preconditioning’ with Low Dose Lipopolysaccharide Aggravates the Organ Injury / Dysfunction Caused by Hemorrhagic Shock in Rats

    PubMed Central

    Sordi, Regina; Chiazza, Fausto; Patel, Nimesh S. A.; Doyle, Rachel A.; Collino, Massimo; Thiemermann, Christoph

    2015-01-01

    Methods Male rats were ‘pretreated’ with phosphate-buffered saline (PBS; i.p.) or LPS (1 mg/kg; i.p.) 24 h prior to HS. Mean arterial pressure (MAP) was maintained at 30 ± 2 mmHg for 90 min or until 25% of the shed blood had to be re-injected to sustain MAP. This was followed by resuscitation with the remaining shed blood. Four hours after resuscitation, parameters of organ dysfunction and systemic inflammation were assessed. Results HS resulted in renal dysfunction, and liver and muscular injury. At a first glance, LPS preconditioning attenuated organ dysfunction. However, we discovered that HS-rats that had been preconditioned with LPS (a) were not able to sustain a MAP at 30 mmHg for more than 50 min and (b) the volume of blood withdrawn in these animals was significantly less than in the PBS-control group. This effect was associated with an enhanced formation of the nitric oxide (NO) derived from inducible NO synthase (iNOS). Thus, a further control group in which all animals were resuscitated after 50 min of hemorrhage was performed. Then, LPS preconditioning aggravated both circulatory failure and organ dysfunction. Most notably, HS-rats pretreated with LPS exhibited a dramatic increase in NF-?B activation and pro-inflammatory cytokines. Conclusion In conclusion, LPS preconditioning predisposed animals to an earlier vascular decompensation, which may be mediated by an excess of NO production secondary to induction of iNOS and activation of NF-?B. Moreover, LPS preconditioning increased the formation of pro-inflammatory cytokines, which is likely to have contributed to the observed aggravation of organ injury/dysfunction caused by HS. PMID:25830444

  11. PVM and IP multicast

    SciTech Connect

    Dunigan, T.H.; Hall, K.A.

    1996-12-01

    This report describes a 1994 demonstration implementation of PVM that uses IP multicast. PVM`s one-to-many unicast implementation of its pvm{_}mcast() function is replaced with reliable IP multicast. Performance of PVM using IP multicast over local and wide-area networks is measured and compared with the original unicast implementation. Current limitations of IP multicast are noted.

  12. Turfgrass evapotranspiration: Responses to shade preconditioning

    Microsoft Academic Search

    C. M. Feldhake; J. D. Butler; R. E. Danielson

    1985-01-01

    Sixteen minilysimeters were used in a study to determine the effect of preconditioning to shade on evapotranspiration (ET) by Kentucky bluegrass (Poa pratensis L. var ‘Merion’). Grass that had been preconditioned to 100, 71, 51, and 27% of possible photosynthetically active radiation (PAR) was subjected to full sun (100% PAR) or full shade (2% PAR) for one day periods. Canopy

  13. Preconditioning Techniques in Computational Fluid Dynamics

    Microsoft Academic Search

    E. Turkel

    1999-01-01

    An overview of preconditioning for the steady-state compressible inviscid fluid dynamic equations is presented. Extensions to the Navier-Stokes equations are also considered. These preconditioners are necessary for many algorithms in order to have the correct behavior at low speeds and to converge to the solution of the incompressible equations as the Mach number goes to zero. In addition, the preconditioning

  14. (S)-ZJM-289 preconditioning induces a late phase protection against nervous injury induced by transient cerebral ischemia and oxygen-glucose deprivation.

    PubMed

    Zhang, Chao; Zhang, Zhenzhen; Zhao, Qian; Wang, Xuliang; Ji, Hui; Zhang, Yihua

    2014-07-01

    (S)-ZJM-289, a novel nitric oxide (NO)-releasing derivative of 3-n-butylphthalide, induces the neuroprotection in a rat model of focal cerebral ischemia/reperfusion (I/R). However, much is unknown about the late phase effect in the neuroprotection of (S)-ZJM-289 preconditioning. The purpose of this study is to explore the late phase neuroprotection of (S)-ZJM-289 preconditioning, as well as underlying mechanisms involved. Preconditioning with 40-160 mg/kg, (S)-ZJM-289 significantly reduces brain damage after I/R. (S)-ZJM-289 preconditioning is effective when applied 1-3 days before I/R. Moreover, the degrees of neuroprotection offered by (S)-ZJM-289 preconditioning and ischemic preconditioning are virtually identical. (S)-ZJM-289 preconditioning also protects primary cultured cortical neurons against oxygen-glucose deprivation and recovery-induced cytotoxicity in vitro. (S)-ZJM-289 preconditioning significantly increases the generation of NO, but has no effect on the nitric oxide synthase activities. Additionally, (S)-ZJM-289 preconditioning promotes the dissociation between nuclear-factor-E2-related factor (Nrf2) and kelch-like ECH-associated protein 1, and induces Nrf2 nuclear localization. The neuroprotection of (S)-ZJM-289 preconditioning is blocked by Nrf2-siRNA in vitro. (S)-ZJM-289 preconditioning up-regulates antioxidant enzymes against nervous injury. (S)-ZJM-289 preconditioning significantly activates extracellular regulated protein kinases (ERK) and inhibits c-Jun N-terminal kinases signaling cascade. The neuroprotection is abolished by the ERK inhibitor PD98059 in vitro. Subsequently, (S)-ZJM-289 preconditioning increases the levels of anti-apoptotic protein B cell lymphoma 2 (Bcl-2) and inhibited the translocation of Bcl-2 associated X to the mitochondria, thus attenuating the release of cytochrome c from the mitochondria and the activation of downstream caspase. These results suggest that (S)-ZJM-289 preconditioning exerts the late phase protection against nervous injury induced by transient cerebral ischemia and oxygen-glucose deprivation. PMID:24277159

  15. Preconditioning via Angiotensin Type 2 Receptor Activation Improves Therapeutic Efficacy of Bone Marrow Mononuclear Cells for Cardiac Repair

    PubMed Central

    Wang, Lihan; Jiang, Zhi; Liu, Xianbao; Yu, Hong; Zhang, Zhaocai; Chen, Huiqiang; Chen, Han; Steinhoff, Gustav; Li, Jun; Jian’an Wang

    2013-01-01

    Background The therapeutic efficiency of bone marrow mononuclear cells (BMMNCs) autologous transplantation for myocardial infarction (MI) remains low. Here we developed a novel strategy to improve cardiac repair by preconditioning BMMNCs via angiotensin II type 2 receptor (AT2R) stimulation. Methods and Results Acute MI in rats led to a significant increase of AT2R expression in BMMNCs. Preconditioning of BMMNCs via AT2R stimulation directly with an AT2R agonist CGP42112A or indirectly with angiotensin II plus AT1R antagonist valsartan led to ERK activation and increased eNOS expression as well as subsequent nitric oxide generation, ultimately improved cardiomyocyte protection in vitro as measured by co-culture approach. Intramyocardial transplantation of BMMNCs preconditioned via AT2R stimulation improved survival of transplanted cells in ischemic region of heart tissue and reduced cardiomyocyte apoptosis and inflammation at 3 days after MI. At 4 weeks after transplantation, compared to DMEM and non-preconditioned BMMNCs group, AT2R stimulated BMMNCs group showed enhanced vessel density in peri-infarct region and attenuated infarct size, leading to global heart function improvement. Conclusions Preconditioning of BMMNCs via AT2R stimulation exerts protective effect against MI. Stimulation of AT2R in BMMNCs may provide a new strategy to improving therapeutic efficiency of stem cells for post MI cardiac repair. PMID:24340072

  16. Ischemic Optic Neuropathies

    Microsoft Academic Search

    Anthony C. Arnold

    ? Ischemic optic neuropathy is classified by location as anterior or posterior and by etiology as arteritic or nonarteritic.\\u000a \\u000a \\u000a ? Anterior ischemic optic neuropathy (AION) presents with rapid, usually painless, monocular visual field loss in the presence\\u000a of optic disc edema. \\u000a \\u000a \\u000a \\u000a ? Arteritic AION is typically more severe and more frequently bilateral than nonarteritic AION, and is associated with severe

  17. Inositol 1,4,5-triphosphate receptors and NAD(P)H mediate Ca 2+ signaling required for hypoxic preconditioning of hippocampal neurons

    Microsoft Academic Search

    P. E. Bickler; C. S. Fahlman; J. Gray; W. McKleroy

    2009-01-01

    Exposure of neurons to a non-lethal hypoxic stress greatly reduces cell death during subsequent severe ischemia (hypoxic preconditioning, HPC). In organotypic cultures of rat hippocampus, we demonstrate that HPC requires inositol triphosphate (IP3) receptor-dependent Ca2+ release from the endoplasmic reticulum (ER) triggered by increased cytosolic NAD(P)H. Ca2+ chelation with intracellular BAPTA, ER Ca2+ store depletion with thapsigargin, IP3 receptor block

  18. Preconditioning the diabetic human myocardium

    PubMed Central

    Sivaraman, Vivek; Hausenloy, Derek J; Wynne, Abigail M; Yellon, Derek M

    2010-01-01

    Abstract Our objective was to determine whether human diabetic myocardium is amenable to the cardioprotective actions of ischaemic preconditioning. Human right atrial appendages were harvested from diabetic and non-diabetic patients undergoing elective coronary artery bypass graft surgery. The atrial trabeculae were isolated and subjected to 90 min. of hypoxia followed by 120 min. of reoxygenation, following which the percentage recovery of baseline contractile function was determined. The atrial trabeculae were randomized to: (i) controls (groups 1 and 3); (ii) standard hypoxic preconditioning (HPC) protocol consisting of 4 min. of hypoxia/16 min. of reoxygenation before the 90 min. index hypoxic period (groups 2 and 4); (iii) Prolonged HPC protocol consisting of: 7 min. of hypoxia /16 min. of reoxygenation before the index hypoxic period (group 5). In addition, basal levels of Akt phosphorylation were determined in right atrial appendages harvested from non-diabetic patients and diabetic patients to determine whether PI3K-Akt signalling is down-regulated in the diabetic heart. Standard HPC improved baseline contractile function in human atrial trabeculae harvested from non-diabetic patients (52.4 ± 3.8% with HPC versus 30.0 ± 3.2% in control: P= 0.001; N= 6/group), but not in atrial trabeculae isolated from diabetic patients (22.6 ± 3.3% with HPC versus 28.5 ± 1.9% in control: P > 0.05; N= 6/group). However, the prolonged HPC protocol did improve baseline contractile function in atrial trabeculae harvested from diabetic patients (42.0 ± 2.4% with HPC versus 28.5 ± 1.9% in control: P= 0.001; N? 6/group). Western blot analysis demonstrated lower levels of phosphorylated Akt in diabetic myocardium compared to non-diabetic myocardium (0.13 ± 0.03 arbitrary units versus 0.39 ± 0.11 arbitrary units: P= 0.047; N? 4/group). From the data obtained it appears that the threshold for preconditioning the diabetic myocardium is elevated which may be related to the down-regulation of the PI3K-Akt pathway. PMID:19508386

  19. Income Protection (IP) Insurance 

    E-print Network

    Stokes, Kenneth; Barnaby, G. A. Art; Waller, Mark L.; Outlaw, Joe

    1999-06-09

    Income Protection (IP) Insurance Kenneth Stokes, G.A. ?Art? Barnaby, Mark Waller and Joe Outlaw* The Income Protection (IP) program insures the producer against lost income from reductions in yield or price. This policy pays when the harvested...

  20. Ischemic Stroke and Neuroprotection

    PubMed Central

    Onwuekwe, IO; Ezeala-Adikaibe, B

    2012-01-01

    Stroke is a major cause of morbidity and mortality in both developed and developing countries of the world. Greater understanding of the pathophysiology of neuronal damage in ischemic stroke has generated interest in neuroprotection as a management strategy. This paper aims to review the current concept and place of neuroprotection in ischemic stroke. An extensive search of all materials related to the topic was made using library sources including Pubmed and Medline searches. Current research findings were also included. The findings are as presented. Neuroprotection is an increasingly recognized management strategy in ischemic stroke that promises to assist clinicians in reducing stroke mortality rates and improving the quality of life of survivors. PMID:23439855

  1. Immunizing Beef Calves: A Preconditioning Immunization Concept 

    E-print Network

    Faries Jr., Floron C.

    2000-12-20

    Properly vaccinating an entire herd, including pregnant cows, calves, replacement heifers and bulls, can prevent disease outbreaks caused by both dormant and incubating infections. This preconditioning immunization helps unborn, nursing and weanling...

  2. IP SwitchingIP Switching and Label Switchingand Label Switching

    E-print Network

    Jain, Raj

    Raj Jain 1 IP SwitchingIP Switching and Label Switchingand Label Switching Raj Jain Professor Switching vs routing q IP Switching (Ipsilon) q Tag Switching (CISCO) q Multi-protocol label switching (Cont)Routing vs Switching (Cont) On ATM networks: q IP routers use IP addresses Reassemble IP

  3. Laser thermal preconditioning enhances dermal wound repair

    NASA Astrophysics Data System (ADS)

    Wilmink, Gerald J.; Carter, Terry; Davidson, Jeffrey M.; Jansen, E. Duco

    2008-02-01

    Preconditioning tissues with an initial mild thermal stress, thereby eliciting a stress response, can serve to protect tissue from subsequent stresses. Patients at risk for impaired healing, such as diabetics, can benefit from therapeutic methods which enhance wound repair. We present a laser thermal preconditioning protocol that accelerates cutaneous wound repair in a murine model. A pulsed diode laser (? = 1.86 ?m, ? p = 2 ms, 50 Hz, H = 7.64 mJ/cm2) was used to precondition mouse skin before incisional wounds were made. The preconditioning protocol was optimized in vitro and in vivo using hsp70 expression, cell viability, and temperature measurements as benchmarks. Hsp70 expression was non-invasively monitored using a transgenic mouse strain with the hsp70 promoter driving luciferase expression. Tissue temperature recordings were acquired in real time using an infrared camera. Wound repair was assessed by measuring hsp70 expression, biomechanical properties, and wound histology for up to 24 d. Bioluminescence (BLI) was monitored with the IVIS 200 System (Xenogen) and tensile properties with a tensiometer (BTC-2000). The in vivo BLI studies indicated that the optimized laser preconditioning protocol increased hsp70 expression by 15-fold. The tensiometer data revealed that laser preconditioned wounds are ~40% stronger than control wounds at 10 days post surgery. Similar experiments in a diabetic mouse model also enhanced wound repair strength. These results indicate that 1) noninvasive imaging methods can aid in the optimization of novel laser preconditioning methods; 2) that optimized preconditioning with a 1.86 ?m diode laser enhances early wound repair.

  4. Targeting ischemic memory.

    PubMed

    Aras, Omer; Dilsizian, Vasken

    2007-02-01

    Long-chain free fatty acids and glucose account for the vast majority of ATP production in the heart. An alteration of fatty acid oxidation is considered to be a sensitive marker of ischemia and myocardial damage. Recently, several radiolabeled fatty acid analogs have been introduced to assess myocardial cellular function. The use of such analogs has enabled the analysis of cardiac metabolism and led to the identification of prior ischemic events, termed 'ischemic memory'. Such advances will find use in the clinical setting for the diagnosis and treatment of subclinical or progressive cardiovascular disorders, as in acute coronary syndrome, that often remain elusive with traditional imaging approaches. PMID:17134889

  5. Role of MicroRNAs in innate neuroprotection mechanisms due to preconditioning of the brain

    PubMed Central

    Jimenez-Mateos, Eva M.

    2015-01-01

    Insults to the brain that are sub-threshold for damage activate endogenous protective pathways, which can temporarily protect the brain against a subsequent harmful episode. This mechanism has been named as tolerance and its protective effects have been shown in experimental models of ischemia and epilepsy. The preconditioning-stimulus can be a short period of ischemia or mild seizures induced by low doses of convulsant drugs. Gene-array profiling has shown that both ischemic and epileptic tolerance feature large-scale gene down-regulation but the mechanism are unknown. MicroRNAs are a class of small non-coding RNAs of ~20–22 nucleotides length which regulate gene expression at a post-transcriptional level via mRNA degradation or inhibition of protein translation. MicroRNAs have been shown to be regulated after non-harmful and harmful stimuli in the brain and to contribute to neuroprotective mechanisms. This review focuses on the role of microRNAs in the development of tolerance following ischemic or epileptic preconditioning. PMID:25954143

  6. Lrg participates in lipopolysaccharide preconditioning-induced brain ischemia injury via TLR4 signaling pathway.

    PubMed

    Gong, Gu; Bai, Shurong; Wu, Wei; Hu, Ling; Liu, Yinghai; Niu, Jie; Dai, Xuemei; Yin, Liang; Wang, Xiaowu

    2014-09-01

    Lipopolysaccharide (LPS) preconditioning is a powerful neuroprotective phenomenon by which an injurious stimulus renders the brain resistant to a subsequent damaging ischemic insult. The LPS response gene (Lrg) is a recently identified gene in human dental pulp cells treated with LPS. However, the role and mechanism of Lrg in brain ischemia injury have not yet been demonstrated. Here, we sought to determine whether Lrg participates in LPS preconditioning-induced brain ischemia injury. The Lrg protein accumulates in brain tissue after middle cerebral artery occlusion (MCAO). Furthermore, knockdown of Lrg by small interfering RNA (siRNA) significantly increased the infarct size of brain injury. In addition, we investigated the mechanism of Lrg in brain ischemia injury. Lrg-siRNA could regulate inflammatory cytokine expression. Moreover, interleukin-1 receptor-associated kinase 1 (IRAK-1) and nuclear factor Kappa B (NF-?B) p65 protein levels were significantly increased by Lrg-siRNA in mice after MCAO. Conversely, interferon regulatory factor 3 (IRF3) protein level was decreased by Lrg-siRNA. Taken together, these results suggest that Lrg regulates the expression of inflammatory cytokines in LPS preconditioning-induced brain ischemia injury via the toll-like receptor 4 (TLR4) signaling pathway. Lrg may therefore serve as a novel therapeutic target for brain ischemia injury. PMID:24526448

  7. Mitochondrial mechanisms in cerebral vascular control: shared signaling pathways with preconditioning.

    PubMed

    Busija, David W; Katakam, Prasad V

    2014-01-01

    Mitochondrial-initiated events protect the neurovascular unit against lethal stress via a process called preconditioning, which independently promotes changes in cerebrovascular tone through shared signaling pathways. Activation of adenosine triphosphate (ATP)-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels) is a specific and dependable way to induce protection of neurons, astroglia, and cerebral vascular endothelium. Through the opening of mitoKATP channels, mitochondrial depolarization leads to activation of protein kinases and transient increases in cytosolic calcium (Ca(2+)) levels that activate terminal mechanisms that protect the neurovascular unit against lethal stress. The release of reactive oxygen species from mitochondria has similar protective effects. Signaling elements of the preconditioning pathways also are involved in the regulation of vascular tone. Activation of mitoKATP channels in cerebral arteries causes vasodilation, with cell-specific contributions from the endothelium, vascular smooth muscles, and nerves. Preexisting chronic conditions, such as insulin resistance and/or diabetes, prevent preconditioning and impair relaxation to mitochondrial-centered responses in cerebral arteries. Surprisingly, mitochondrial activation after anoxic or ischemic stress appears to protect cerebral vascular endothelium and promotes the restoration of blood flow; therefore, mitochondria may represent an important, but underutilized target in attenuating vascular dysfunction and brain injury in stroke patients. PMID:24862206

  8. Remote ischemic conditioning: a novel way to treat ischemia-related injury of limbs.

    PubMed

    Tengfei, Li; Jiangning, Wang

    2015-05-01

    Remote ischemic conditioning (RIC) including remote ischemic preconditioning (RIPC) and remote ischemic postconditioning (RIPostC) is widely reported to be able to prevent many organs, such as heart, brain, and skeletal muscle from ischemia-related injury. However, the clinical application of RIC is confined to treating myocardial infarction and stroke. Since RIC could prevent skeletal muscle from ischemia-related injury, and was effective in heart and brain treatments, we hypothesized RIC could treat ischemia-related injury of limbs, such as diabetic foot, Buerger's disease, plantation of severed limb, and crush injury. As we know, many researches not only proved the promising clinical applications of RIC, but also researched the mechanisms in animal models. Our hypothesis could be confirmed by these researches. PMID:25737337

  9. Hypoxic preconditioning increases skin oxygenation and viability but does not alter VEGF expression or vascular density.

    PubMed

    Schlaudraff, Kai U; Pepper, Michael S; Tkatchouk, Elena N; Ehrenburg, Igor; Alizadeh, Navid; Montandon, Denys; Pittet, Brigitte

    2008-01-01

    Intermittent hypoxia is known to elicit adaptive changes that increase tissue oxygen delivery. We investigated the effects of intermittent hypoxic exposure (IHE) in normal skin (course study) and evaluated whether preoperative IHE-preconditioning alleviates acute ischemic injury in skin flaps (flap study). For 4 weeks, 55 rats were exposed to a daily IHE-session (6 hypoxic cycles, 9% O(2), 6 to 10 min) separated by 3 min of reoxygenation (20.9% O(2)). The time course of intracutaneous PO(2) was measured at weekly intervals. VEGF/VEGF-receptor-mRNA and vascular density were measured in normal skin before and after 1, 2, 3, and 4 weeks of the IHE course (20 rats). In 35 rats, skin flaps were elevated after IHE and similar studies were undertaken in samples from 3 flap areas at postoperative days 0.5, 2, and 4. Additionally, flap survival and cutaneous blood flow were quantitated. In normal skin, PO(2) was initially significantly decreased during the hypoxic cycles (PO(2) 4.1 +/- 1.5 mmHg). After 4 weeks of IHE, PO(2) (34.5 +/- 5.8 mmHg) was maintained even under hypoxic conditions. In flaps, IHE led to a 2.6-fold increase in PO(2), increased flap survival (+ 19.4%, day 7), and blood flow (+ 19.1%, day 10) (p < 0.01). In neither study did IHE-preconditioning increase VEGF/VEGF-receptor-mRNA expression or vascular density. We conclude that (1) IHE induces pronounced hypoxia in the skin, but progressive adaptation occurs within 4 weeks, (2) preoperative IHE-preconditioning leads to significantly higher PO(2), blood flow, and tissue survival in ischemic skin flaps, and (3) the transient hypoxia induced by IHE does not alter expression of VEGF or its receptors nor does it trigger angiogenesis. PMID:18331223

  10. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  11. Imaging of Ischemic Stroke

    PubMed Central

    Leiva-Salinas, Carlos; Wintermark, Max

    2010-01-01

    This content discusses the individual components of multi-modal CT and multi-modal MRI, present the current status of neuroimaging for the evaluation of the acute ischemic stroke, and address the potential role of a combined multimodal stroke protocol. PMID:20974371

  12. SIMPLE MACHINE PERFUSION SIGNIFICANTLY ENHANCES HEPATOCYTE YIELDS OF ISCHEMIC AND FRESH RAT LIVERS

    PubMed Central

    Izamis, Maria-Louisa; Calhoun, Candice; Uygun, Basak E.; Guzzardi, Maria Angela; Price, Gavrielle; Luitje, Martha; Saeidi, Nima; Yarmush, Martin L.; Uygun, Korkut

    2014-01-01

    The scarcity of viable hepatocytes is a significant bottleneck in cell transplantation, drug discovery, toxicology, tissue engineering, and bioartificial assist devices, where trillions of high-functioning hepatocytes are needed annually. We took the novel approach of using machine perfusion to maximize cell recovery, specifically from uncontrolled cardiac death donors, the largest source of disqualified donor organs. In a rat model, we developed a simple 3 hour room temperature (20±2°C) machine perfusion protocol to treat non-premedicated livers exposed to 1 hour of warm (34°C) ischemia. Treated ischemic livers were compared to fresh, fresh-treated and untreated ischemic livers using viable hepatocyte yields and in vitro performance as quantitative endpoints. Perfusion treatment resulted in both a 25-fold increase in viable hepatocytes from ischemic livers, and a 40% increase from fresh livers. While cell morphology and function in suspension and plate cultures of untreated warm ischemic cells was significantly impaired, treated warm ischemic cells were indistinguishable from fresh hepatocytes. Further, a strong linear correlation between tissue ATP and cell yield enabled accurate evaluation of the extent of perfusion recovery. Maximal recovery of warm ischemic liver ATP content appears to be correlated with optimal flow through the microvasculature. These data demonstrate that the inclusion of a simple perfusion-preconditioning step can significantly increase the efficiency of functional hepatocyte yields and the number of donor livers that can be gainfully utilized. PMID:25431743

  13. Pharmacologic preconditioning of random-pattern skin flap in rats using local cyclosporine and FK-506: interaction with nitric oxide system.

    PubMed

    Nezami, Behtash Ghazi; Ghazinezami, Behtash; Rahimpour, Sina; Gholipour, Taha; Ghasemi, Mehdi; Sadeghipour, Hamed; Mehr, Shahram Ejtemaie; Emami-Razavi, Seyed Hassan; Dehpour, Ahmad Reza

    2007-10-01

    It has been suggested that immunophilin ligands such as cyclosporine and FK-506 (tacrolimus) affect the survival of ischemic tissues. Our objective was to show an acute effect of local cyclosporin-A (CsA) and FK-506 on ischemic protection in a random-pattern skin-flap model in rats and investigate the effect of nitric oxide (NO) pathways as a modulator of protection of these agents. Ninety male Sprague-Dawley rats were randomly assigned to treatment groups. Bipedicled dorsal flaps (2 x 8 cm) were elevated at midline. Prior to cutting the cranial pedicle to induce permanent ischemia, pharmacologic preconditioning groups received local injection of CsA (0.3, 1, or 3 nmol/flap) or FK-506 (0.01, 0.03, or 0.1 pmol/flap), and the ischemic preconditioning (IPC) group underwent temporary clamping of the cranial pedicle. At the seventh day postoperatively, the survival of the flaps was measured. In other groups, nitric oxide synthase inhibitor N omega-nitro-l-arginine methyl ester hydrochloride (L-NAME) was administered with effective CsA and FK-506, and ischemic preconditioning. Nitric oxide precursor L-arginine doses were also studied, and a systemic subeffective dose (100 mg/kg) was coadministered with subeffective CsA and FK-506. Significant increase in flap survival was obtained with CsA (1 nmol/flap), FK-506 (0.1 pmol/flap), and IPC. These protections were abolished by systemic administration of L-NAME (10 mg/kg). Coadministration of subeffective doses of CsA (0.3 nmol/flap) and FK-506 (0.03 pmol/flap), with subeffective systemic l-arginine, significantly improved flap survival.Pharmacologic preconditioning with local, single, low doses of CsA or FK-506 is shown to be even more effective than IPC. Administration of the NOS substrate l-arginine potentiates these effects. PMID:17901737

  14. Hypoxia-preconditioned adipose tissue-derived mesenchymal stem cell increase the survival and gene expression of engineered neural stem cells in a spinal cord injury model

    Microsoft Academic Search

    Jin Soo Oh; Yoon Ha; Sung Su An; Momin Khan; William A. Pennant; Hyo Jin Kim; Do Heum Yoon; Minhyung Lee; Keung Nyun Kim

    2010-01-01

    Hypoxic preconditioning (HP) is a novel strategy to make stem cells resistant to the ischemic environment they encounter after transplantation into injured tissue; this strategy improves survival of both the transplanted cells and the host cells at the injury site. Using both in vitro and in vivo injury models, we confirmed that HP-treated adipose tissue-derived mesenchymal stem cells (HP-AT-MSCs) increased

  15. Aging-related Decrease of Human ASC Angiogenic Potential Is Reversed by Hypoxia Preconditioning Through ROS Production

    PubMed Central

    Barros, Sandra De; Dehez, Stéphanie; Arnaud, Emmanuelle; Barreau, Corinne; Cazavet, Alexandre; Perez, Guillaume; Galinier, Anne; Casteilla, Louis; Planat-Bénard, Valérie

    2013-01-01

    Adipose stroma/stem cells (ASC) represent an ideal source of autologous cells for cell-based therapy. Their transplantation enhances neovascularization after experimental ischemic injury. Aging is associated with a progressive decrease in the regenerative potential of mesenchymal stem cells (MSCs) from bone marrow. This work aims to determine the aging effect on human ASC capacities. First, we show that aging impairs angiogenic capacities of human ASC (hASC) in a mouse ischemic hindlimb model. Although no change in hASC number, phenotype, and proliferation was observed with aging, several mechanisms involved in the adverse effects of aging have been identified in vitro combining a concomitant decrease in (i) ASC ability to differentiate towards endothelial cells, (ii) secretion of proangiogenic and pro-survival factors, and (iii) oxidative stress. These effects were counteracted by a hypoxic preconditioning that improved in vivo angiogenic capacities of hASC from older donors, while hASC from young donors that have a strong ability to manage hypoxic stress were not. Finally, we identified reactive oxygen species (ROS) generation as a key signal of hypoxia on hASC angiogenic capacities. This study demonstrates for the first time that age of donor impaired angiogenic capacities of hASC in ischemic muscle and change in ROS generation by hypoxic preconditioning reverse the adverse effect of aging. PMID:23070114

  16. Ischemic conditioning: the challenge of protecting the diabetic heart

    PubMed Central

    Wider, Joseph

    2014-01-01

    The successful clinical translation of novel therapeutic strategies to attenuate lethal myocardial ischemia-reperfusion injury and limit infarct size has been identified as a major unmet need, and is of particular importance in patients with type-2 diabetes. There is a wealth of preclinical evidence that ischemic conditioning (encompassing the three paradigms of preconditioning, postconditioning and remote conditioning) is profoundly cardioprotective and, via up-regulation of endogenous signaling cascades, renders the heart resistant to infarction. However, current phase II trials aimed at exploiting ischemic conditioning for the clinical treatment of myocardial ischemia-reperfusion injury have yielded mixed results, possibly reflecting the emerging concern that the efficacy of conditioning-induced cardioprotection may be compromised in the diabetic heart. Our goal in this review is to provide a summary of our present understanding of the effect of type-2 diabetes on the infarct-sparing effect of ischemic conditioning, and the challenges of limiting ischemia-reperfusion injury in the diabetic heart. PMID:25414825

  17. Fetal asphyctic preconditioning modulates the acute cytokine response thereby protecting against perinatal asphyxia in neonatal rats

    PubMed Central

    2013-01-01

    Background Perinatal asphyxia (PA) is a major cause of brain damage and neurodevelopmental impairment in infants. Recent investigations have shown that experimental sublethal fetal asphyxia (FA preconditioning) protects against a subsequent more severe asphyctic insult at birth. The molecular mechanisms of this protection have, however, not been elucidated. Evidence implicates that inflammatory cytokines play a protective role in the induction of ischemic tolerance in the adult brain. Accordingly, we hypothesize that FA preconditioning leads to changes in the fetal cytokine response, thereby protecting the newborn against a subsequent asphyctic insult. Methods In rats, FA preconditioning was induced at embryonic day 17 by clamping the uterine vasculature for 30 min. At term birth, global PA was induced by placing the uterine horns, containing the pups, in a saline bath for 19 min. We assessed, at different time points after FA and PA, mRNA and protein expression of several cytokines and related receptor mRNA levels in total hemispheres of fetal and neonatal brains. Additionally, we measured pSTAT3/STAT3 levels to investigate cellular responses to these cytokines. Results Prenatally, FA induced acute downregulation in IL-1?, TNF-? and IL-10 mRNA levels. At 96 h post FA, IL-6 mRNA and IL-10 protein expression were increased in FA brains compared with controls. Two hours after birth, all proinflammatory cytokines and pSTAT3/STAT3 levels decreased in pups that experienced FA and/or PA. Interestingly, IL-10 and IL-6 mRNA levels increased after PA. When pups were FA preconditioned, however, IL-10 and IL-6 mRNA levels were comparable to those in controls. Conclusions FA leads to prenatal changes in the neuroinflammatory response. This modulation of the cytokine response probably results in the protective inflammatory phenotype seen when combining FA and PA and may have significant implications for preventing post-asphyctic perinatal encephalopathy. PMID:23351591

  18. Photonic IP routing

    Microsoft Academic Search

    K.-I. Kitayama; N. Wada

    1999-01-01

    A photonic Internet protocol (IP) routing is proposed in which the IP address, mapped onto optical code, is recognized by performing optical correlation in the time domain in a parallel manner. Preliminary experiment shows that it can process 6.5×109 packets per second. It will help overcome the bottleneck in current electrical IP routers; i.e., the time it takes to look

  19. Behavioral/Systems/Cognitive Octopamine Mediates Thermal Preconditioning of the

    E-print Network

    Robertson, Meldrum

    ) in the metathoracic ganglion decreased during heat stress. We measured of physiological adaptations that have evolved to protect nervous systems from heat stress. Preconditioning locusts l OA) mimicked heat shock preconditioning and improved the thermotolerance of the motor pattern

  20. Mitochondrial Dihydrolipoamide Dehydrogenase Is Upregulated in Response to Intermittent Hypoxic Preconditioning

    PubMed Central

    Li, Rongrong; Luo, Xiaoting; Wu, Jinzi; Thangthaeng, Nopporn; Jung, Marianna E.; Jing, Siqun; Li, Linya; Ellis, Dorette Z.; Liu, Li; Ding, Zhengnian; Forster, Michael J.; Yan, Liang-Jun

    2015-01-01

    Intermittent hypoxia preconditioning (IHP) has been shown to protect neurons against ischemic stroke injury. Studying how proteins respond to IHP may identify targets that can help fight stroke. The objective of the present study was to investigate whether mitochondrial dihydrolipoamide dehydrogenase (DLDH) would respond to IHP and if so, whether such a response could be linked to neuroprotection in ischemic stroke injury. To do this, we subjected male rats to IHP for 20 days and measured the content and activity of DLDH as well as the three ?-keto acid dehydrogenase complexes that contain DLDH. We also measured mitochondrial electron transport chain enzyme activities. Results show that DLDH content was indeed upregulated by IHP and this upregulation did not alter the activities of the three ?-keto acid dehydrogenase complexes. Results also show that the activities of the five mitochondrial complexes (I-V) were not altered either by IHP. To investigate whether IHP-induced DLDH upregulation is linked to neuroprotection against ischemic stroke injury, we subjected both DLDH deficient mouse and DLDH transgenic mouse to stroke surgery followed by measurement of brain infarction volume. Results indicate that while mouse deficient in DLDH had exacerbated brain injury after stroke, mouse overexpressing human DLDH also showed increased brain injury after stroke. Therefore, the physiological significance of IHP-induced DLDH upregulation remains to be further investigated.

  1. Mitochondrial Dihydrolipoamide Dehydrogenase is Upregulated in Response to Intermittent Hypoxic Preconditioning.

    PubMed

    Li, Rongrong; Luo, Xiaoting; Wu, Jinzi; Thangthaeng, Nopporn; Jung, Marianna E; Jing, Siqun; Li, Linya; Ellis, Dorette Z; Liu, Li; Ding, Zhengnian; Forster, Michael J; Yan, Liang-Jun

    2015-01-01

    Intermittent hypoxia preconditioning (IHP) has been shown to protect neurons against ischemic stroke injury. Studying how proteins respond to IHP may identify targets that can help fight stroke. The objective of the present study was to investigate whether mitochondrial dihydrolipoamide dehydrogenase (DLDH) would respond to IHP and if so, whether such a response could be linked to neuroprotection in ischemic stroke injury. To do this, we subjected male rats to IHP for 20 days and measured the content and activity of DLDH as well as the three ?-keto acid dehydrogenase complexes that contain DLDH. We also measured mitochondrial electron transport chain enzyme activities. Results show that DLDH content was indeed upregulated by IHP and this upregulation did not alter the activities of the three ?-keto acid dehydrogenase complexes. Results also show that the activities of the five mitochondrial complexes (I-V) were not altered either by IHP. To investigate whether IHP-induced DLDH upregulation is linked to neuroprotection against ischemic stroke injury, we subjected both DLDH deficient mouse and DLDH transgenic mouse to stroke surgery followed by measurement of brain infarction volume. Results indicate that while mouse deficient in DLDH had exacerbated brain injury after stroke, mouse overexpressing human DLDH also showed increased brain injury after stroke. Therefore, the physiological significance of IHP-induced DLDH upregulation remains to be further investigated. PMID:26078703

  2. Xenon preconditioning: molecular mechanisms and biological effects

    PubMed Central

    2013-01-01

    Xenon is one of noble gases and has been recognized as an anesthetic for more than 50?years. Xenon possesses many of the characteristics of an ideal anesthetic, but it is not widely applied in clinical practice mainly because of its high cost. In recent years, numerous studies have demonstrated that xenon as an anesthetic can exert neuroprotective and cardioprotective effects in different models. Moreover, xenon has been applied in the preconditioning, and the neuroprotective and cardioprotective effects of xenon preconditioning have been investigated in a lot of studies in which some mechanisms related to these protections are proposed. In this review, we summarized these mechanisms and the biological effects of xenon preconditioning. PMID:23305274

  3. PARALLEL GLOBAL LINE JACOBI PRECONDITIONING IN NIMROD Carl Sovinec, LANL

    E-print Network

    Sovinec, Carl

    PARALLEL GLOBAL LINE JACOBI PRECONDITIONING IN NIMROD Carl Sovinec, LANL June 11, 1999 This note to warrant trying global line Jacobi preconditioning in parallel. Here, I discuss one parallel implementation this global preconditioning will reduce computation time and increase parallel efficiency significantly

  4. Implementation of Deflated Preconditioned Conjugate Gradient

    E-print Network

    Vuik, Kees

    -by-Step Optimizations ·Profiler for Advice ·Modularity and Readability Methodology #12;·DIA Format is best ·Spm% of bandwidth ·Clubbing Kernels ­ Reducing Memory Traffic Deflated Preconditioned Conjugate Gradient bE 1 #12;·Density Contrast 1000:1 · ·False Stop Two Phase Matrix 1 2 2 10 |||| |||| 0 k kexact X XX #12

  5. Preconditioned Iterative Regularization Ill--Posed Problems

    E-print Network

    Plemmons, Robert J.

    Preconditioned Iterative Regularization for Ill--Posed Problems Martin Hanke, \\Lambda James Nagy y for solving large scale structured linear systems Hf = g + j, arising from the discretization of ill­ posed regularized for solving ill­posed problems by using the spectral decomposition of the preconditioner. Key

  6. Preconditioning and tolerance against cerebral ischaemia

    PubMed Central

    Dirnagl, Ulrich; Becker, Kyra; Meisel, Andreas

    2009-01-01

    Neuroprotection and brain repair in patients after acute brain damage are still major unfulfilled medical needs. Pharmacological treatments are either ineffective or confounded by adverse effects. Consequently, endogenous mechanisms by which the brain protects itself against noxious stimuli and recovers from damage are being studied. Research on preconditioning, also known as induced tolerance, over the past decade has resulted in various promising strategies for the treatment of patients with acute brain injury. Several of these strategies are being tested in randomised clinical trials. Additionally, research into preconditioning has led to the idea of prophylactically inducing protection in patients such as those undergoing brain surgery and those with transient ischaemic attack or subarachnoid haemorrhage who are at high risk of brain injury in the near future. In this Review, we focus on the clinical issues relating to preconditioning and tolerance in the brain; specifically, we discuss the clinical situations that might benefit from such procedures. We also discuss whether preconditioning and tolerance occur naturally in the brain and assess the most promising candidate strategies that are being investigated. PMID:19296922

  7. Managing one master data – challenges and preconditions

    Microsoft Academic Search

    Risto Silvola; Olli Jaaskelainen; Hanna Kropsu-Vehkapera; Harri Haapasalo

    2011-01-01

    Purpose – This paper aims to provide a framework of the multidimensional concept of one master data. Preconditions required for successful one master data implementation and usage in large high-tech companies are presented and related current challenges companies have today are identified. Design\\/methodology\\/approach – This paper is qualitative in nature. First, literature was studied to find out the elements of

  8. Revealing Preconditions for Trustful Collaboration in CSCL

    ERIC Educational Resources Information Center

    Gerdes, Anne

    2010-01-01

    This paper analyses preconditions for trust in virtual learning environments. The concept of trust is discussed with reference to cases reporting trust in cyberspace and through a philosophical clarification holding that trust in the form of self-surrender is a common characteristic of all human co-existence. In virtual learning environments,…

  9. Preconditioning matrices for Chebyshev derivative operators

    NASA Technical Reports Server (NTRS)

    Rothman, Ernest E.

    1986-01-01

    The problem of preconditioning the matrices arising from pseudo-spectral Chebyshev approximations of first order operators is considered in both one and two dimensions. In one dimension a preconditioner represented by a full matrix which leads to preconditioned eigenvalues that are real, positive, and lie between 1 and pi/2, is already available. Since there are cases in which it is not computationally convenient to work with such a preconditioner, a large number of preconditioners were studied which were more sparse (in particular three and four diagonal matrices). The eigenvalues of such preconditioned matrices are compared. The results were applied to the problem of finding the steady state solution to an equation of the type u sub t = u sub x + f, where the Chebyshev collocation is used for the spatial variable and time discretization is performed by the Richardson method. In two dimensions different preconditioners are proposed for the matrix which arises from the pseudo-spectral discretization of the steady state problem. Results are given for the CPU time and the number of iterations using a Richardson iteration method for the unpreconditioned and preconditioned cases.

  10. Backward Analysis for Inferring Quantified Preconditions

    Microsoft Academic Search

    Tal Lev-AmiMooly Sagiv; Sumit Gulwani

    2007-01-01

    This paper presents a method to infer preconditions that contain quantifiers. Such invariants can quantify over an unbounded num- ber of storage locations and elements of arrays, and allow shape properties of programs that manipulate pointers and dynamically allocated data structures to be described concisely. The precondi- tions that are found ensure that any assertions that exist in the code

  11. [Neyromidin in ischemic stroke].

    PubMed

    Maksimova, M Iu; Korobkova, D Z; Sineva, N A; Vodop'ianov, N P; Mikhal'chenko, V N

    2013-01-01

    An aim of the study was to evaluate the therapeutic effect of neyromidin in patients with ischemic stroke. Forty patients with acute carotid artery stroke were enrolled into the study. The diagnosis was made on the basis of general clinical methods as well as the neurological examination, CT or MRI scans of the head, investigation of hemodynamic parameters, ECG, ultrasound dopplerography of major brain arteries. Neurological deficit was measured using the Scandinavian Scale. According to the TOAST classification, 14 (35%) of the patients suffered from large vessel disease, 16 (40%) patients were diagnosed with cardioembolic disease and 10 (25%) with the small vessel disease. Patients were randomized to the study and control groups (n=20 patients). All patients received standard treatment. Patients of the study group were treated with neyromidin. The study duration was 80 days. Clinical examinations were performed in the acute phase, on 21st and 80th days after stroke. Better recovery of neurological functions was identified in patients treated with neyromidin compared to control patients. No side-effects of neyromidin was found. Neyromidin is recommended for complex treatment of patients in the acute stage of ischemic stroke of carotid origin. PMID:23612408

  12. Ischemic Stroke Prevention.

    PubMed

    Chaturvedi; Hickenbottom; Levine

    1999-05-01

    More than 700,000 strokes occur annually in the United States--one every 40 to 50 seconds. Although stroke is one of the nation's most expensive diseases to treat, costing $41 billion per year, most strokes (perhaps as many as two thirds) are preventable. Twenty percent of the United States population will have 80% of all strokes; this estimate is based on five established, major risk factors for stroke: hypertension, diabetes mellitus, cigarette smoking, hyperlipidemia, and heart disease. Therefore, stroke is not random but is generally predictable. It is an ideal target for effective prevention strategies that are simple and inexpensive. Ischemic stroke prevention has been shown to be effective in several scenarios: primary prevention, prevention after a transient ischemic attack (TIA), and secondary prevention. Dietary, lifestyle, and risk factor modification; use of aspirin, ticlopidine, clopidogrel, and warfarin; and carotid endarterectomy all have a role in stroke prevention in selected persons. Emerging therapies include the use of vitamins, cerebral arterial angioplasty, and stenting. Annual risk assessment, screening, and intervention should be part of a concerted national effort to reduce the incidence of the third leading cause of death and the number one cause of adult disability in the United States. PMID:11096701

  13. Stroke: transient ischemic attack.

    PubMed

    Silver, Brian; Wulf Silver, Rachel

    2014-05-01

    The definitions of transient ischemic attack (TIA) and stroke have evolved with advancements in medical imaging. Approximately one-third of events that last less than 24 hours are associated with new infarctions on modern imaging sequences. These events, previously called apoplexy, are now called strokes. Approximately 10% of patients with TIA will have a stroke within 90 days without urgent evaluation and management; 50% of these events will occur within the first 48 hours. The ABCD(2) and ABCD(3)-I scores are validated measures that can help predict which patients are at greatest risk. With urgent evaluation and management, the rate of stroke after TIA can be reduced by up to 80%. Measures that reduce the rate of recurrence include rapid diagnosis and management of atrial fibrillation, identification and repair of carotid artery stenosis, early antithrombotic management, and use of statins for appropriate patients. Dual antiplatelet management with aspirin and clopidogrel may be useful in the first 30 days after TIA, but these drugs should not be used in combination after that time. Adverse events, including major bleeding and mortality, occur more frequently than with monotherapy with no reduction in ischemic events. Patients also should be encouraged to adopt lifestyle changes, such as regular exercise and weight loss. PMID:24818554

  14. Mobile IP and protocol authentication extension

    E-print Network

    Nguyen, Phuc V

    2011-01-01

    Mobile IP is an open standard, defined by the Internet Engineering Task Force (IETF) RFC 3220. By using Mobile IP, you can keep the same IP address, stay connected, and maintain ongoing applications while roaming between IP networks. Mobile IP is scalable for the Internet because it is based on IP - any media that can support IP can support Mobile IP.

  15. IPS User's Guide

    Microsoft Academic Search

    Barton P. Miller; Bruce Irvin; Hi Low; Jeff Hollingsworth

    1989-01-01

    IntroductionIPS[2] is an interactive, trace driven performance measurement system for parallel and distributedprograms. It runs on DECstation, Sun, Vax, Sequent Symmetry, and Cray Y-MP computers(or a heterogeneous combination of these computers). IPS provides a large amount of performancedata about the execution of a parallel program, and this information is organized hierarchicallyso that access to it is easy and intuitive.Performance data

  16. Design and synthesis of nitrate esters of aromatic heterocyclic compounds as pharmacological preconditioning agents.

    PubMed

    Fotopoulou, Theano; Iliodromitis, Efstathios K; Koufaki, Maria; Tsotinis, Andrew; Zoga, Anastasia; Gizas, Vassilis; Pyriochou, Anastasia; Papapetropoulos, Andreas; Andreadou, Ioanna; Kremastinos, Dimitrios Th

    2008-04-15

    Ischemic preconditioning (IPC) constitutes an endogenous protective mechanism in which one or more brief periods of myocardial ischemia and reperfusion render the myocardium resistant to a subsequent more-sustained ischemic insult. Pharmacological preconditioning represents an ideal alternative of IPC. We now describe the design and synthesis of indole, quinoline, and purine systems with an attached pharmacophoric nitrate ester group. The indole and quinoline derivatives 4 and 5 possess structural features of the nitrate containing K(ATP) channel openers. Purine analogues 11 and 12, substituted at the position 6 by a piperidine moiety and at position 9 by an alkyl nitrate, could combine the effects of the nitrate containing K(ATP) channel openers and those of adenosine. Compound 13 bears the nicotinamide moiety of nicorandil instead of nitrate ester. Compounds 4, 5, and 11 reduced infarction and the levels of malondialdehyde (MDA) at reperfusion in anesthetized rabbits. Compounds 12 and 13 did not significantly reduce the infarct size. Analogues 4 and 5 increased cGMP and MDA during ischemia, while combined analogue 4 and mitoK(ATP) blocker 5-hydroxydecanoic acid (5-HD) abrogated this benefit suggesting an action through mitoK(ATP) channel opening. Treatment with derivative 11 combined with 5-HD as well as treatment with 11 and adenosine receptor blocker 8-(p-sulfophenyl)theophylline (SPT) did not abrogate cardioprotection. Compound 11 is a lead molecule for the synthesis of novel analogues possessing a dual mode of action through cGMP-mitoK(ATP) channel opening-free radicals and through adenosine receptors. PMID:18328715

  17. Towards a dynamical network view of brain ischemia and reperfusion. Part II: a post-ischemic neuronal state space

    PubMed Central

    DeGracia, Donald J.

    2011-01-01

    The general failure of neuroprotectants in clinical trials of ischemic stroke points to the possibility of a fundamental blind spot in the current conception of ischemic brain injury, the “ischemic cascade”. This is the second in a series of four papers whose purpose is to work towards a revision of the concept of brain ischemia by applying network concepts to develop a bistable model of brain ischemia. We here build the bistable network model of brain ischemia. The central concept is that of a post-ischemic state space. Ischemia, as a quantitative perturbation, is envisioned to push the brain through a series of four phenotypes as a function of the amount of ischemia: the homeostatic, preconditioned, delayed neuronal death and necrotic phenotypes. The phenotypes are meta-stable attractors in the landscape of the post-ischemic state space. The sequence of the phenotypes derives from the mutual antagonism between damage mechanisms and stress responses, each conceived as aggregate ensemble variables. The competition between damage mechanisms and stress responses is posited to have the form of a bistability. Application of bistability to brain ischemia is grounded in the incontrovertible fact that post-ischemic neurons face the mutually exclusive decision to either live or die. PMID:21258657

  18. IP switching and gigabit routers

    Microsoft Academic Search

    P. Newman; G. Minshall; T. Lyon; L. Huston

    1997-01-01

    To cope with the growth in the Internet and corporate IP networks, we require IP routers capable of much higher performance than is possible with existing architectures. This article examines two approaches to the design of a high-performance router, the gigabit router and the IP switch, and then provides some detail on the implementation of an IP switch and the

  19. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    1 Advanced Networking Voice over IP & Other Multimedia Protocols Renato.LoCigno@dit.unitn.it Advanced Networking ­ VoIP - 1 2 VoIP: Integrating Services !" # " $ $ # " % ! ! & # ' ( ) * Renato.LoCigno@dit.unitn.it Advanced Networking ­ VoIP - 1 3 Plain Old Telephone Service (POTS) #12;2 Renato

  20. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    Advanced Networking Voice over IP: Introduction and H.323 standard Renato Lo Cigno Renato.LoCigno@disi.unitn.it #12;Renato.LoCigno@disi.unitn.it Advanced Networking ­ VoIP - 1 2 VoIP: Integrating Services · Voice on IP Networks is just "another application" · Nothing "special" or "specialized" as traditional

  1. PRECONDITIONING BEEF CALVES: ARE EXPECTED PREMIUMS SUFFICIENT TO JUSTIFY THE PRACTICE?

    Microsoft Academic Search

    Kevin C. Dhuyvetter

    2004-01-01

    The concept of preconditioning calves has been around for a long time, yet adoption of the practice has been slow. Current trends in the beef industry likely will increase interest in preconditioning programs. This research estimates premiums received for preconditioned calves and the expected returns from a preconditioning program. Preconditioned calves sold in the fall received a premium of approximately

  2. Preserving Symmetry in Preconditioned Krylov Subspace Methods

    NASA Technical Reports Server (NTRS)

    Chan, Tony F.; Chow, E.; Saad, Y.; Yeung, M. C.

    1996-01-01

    We consider the problem of solving a linear system Ax = b when A is nearly symmetric and when the system is preconditioned by a symmetric positive definite matrix M. In the symmetric case, one can recover symmetry by using M-inner products in the conjugate gradient (CG) algorithm. This idea can also be used in the nonsymmetric case, and near symmetry can be preserved similarly. Like CG, the new algorithms are mathematically equivalent to split preconditioning, but do not require M to be factored. Better robustness in a specific sense can also be observed. When combined with truncated versions of iterative methods, tests show that this is more effective than the common practice of forfeiting near-symmetry altogether.

  3. M-step preconditioned conjugate gradient methods

    NASA Technical Reports Server (NTRS)

    Adams, L.

    1983-01-01

    Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included.

  4. On polynomial preconditioning for indefinite Hermitian matrices

    NASA Technical Reports Server (NTRS)

    Freund, Roland W.

    1989-01-01

    The minimal residual method is studied combined with polynomial preconditioning for solving large linear systems (Ax = b) with indefinite Hermitian coefficient matrices (A). The standard approach for choosing the polynomial preconditioners leads to preconditioned systems which are positive definite. Here, a different strategy is studied which leaves the preconditioned coefficient matrix indefinite. More precisely, the polynomial preconditioner is designed to cluster the positive, resp. negative eigenvalues of A around 1, resp. around some negative constant. In particular, it is shown that such indefinite polynomial preconditioners can be obtained as the optimal solutions of a certain two parameter family of Chebyshev approximation problems. Some basic results are established for these approximation problems and a Remez type algorithm is sketched for their numerical solution. The problem of selecting the parameters such that the resulting indefinite polynomial preconditioners speeds up the convergence of minimal residual method optimally is also addressed. An approach is proposed based on the concept of asymptotic convergence factors. Finally, some numerical examples of indefinite polynomial preconditioners are given.

  5. The Effect of Preinfarction Angina as Ischemic Preconditioning on Myocardial Protection

    Microsoft Academic Search

    Tae-Young Choi; Seung-Jae Tahk; Myeong-Ho Yoon; So-Yeon Choi; Min-Cheol Kim; Heung-Mo Yang; Jung-Hyun Choi; Zhen-Guo Zheng; Long Qi; Hyuk-Jae Chang; Gyo-Seung Hwang; Joon-Han Shin

    Background and Objectives:By measuring the coronary flow reserve (CFR) and echocardiographic left ventri- cular function, the purpose of this study was to evaluate the effect of pre-infarction angina (PA) on myocardial protection in patients with acute myocardial infarction (AMI). Subjects and Methods:Sixty-two patients (mean 54±10 years, 51 males) with first anterior AMI were studied. CFR, defined as the ratio of

  6. Hypoxic Preconditioning Alleviates Ethanol Neurotoxicity: the Involvement of Autophagy

    PubMed Central

    Wang, Haiping; Bower, Kimberly A.; Frank, Jacqueline A.; Xu, Mei; Luo, Jia

    2013-01-01

    Ethanol is a neuroteratogen and neurodegeneration is the most devastating consequence of developmental exposure to ethanol. A sublethal preconditioning has been proposed as a neuroprotective strategy against several central nervous system (CNS) neurodegenerative diseases. We have recently demonstrated that autophagy is a protective response to alleviate ethanol toxicity. A modest hypoxic preconditioning (1% oxygen) did not cause neurotoxicity but induced autophagy (Tzeng et al., 2010). We therefore hypothesize that the modest hypoxic preconditioning may offer a protection against ethanol-induced neurotoxicity. We showed here that the modest hypoxic preconditioning (1% oxygen) for 8 hours significantly alleviated ethanol-induced death of SH-SY5Y neuroblastoma cells. Under the normoxia condition, cell viability in ethanol-exposed cultures (316 mg/dl for 48 hrs) was 49 ± 6% of untreated controls; however, with hypoxic preconditioning, cell viability in the ethanol-exposed group increased to 78 ± 7% of the controls (p < 0.05; n = 3). Bafilomycin A1, an inhibitor of autophagosome and lysosome fusion, blocked hypoxic preconditioning-mediated protection. Similarly, inhibition of autophagic initiation by wortmannin also eliminated hypoxic preconditioning-mediated protection. In contrast, activation of autophagy by rapamycin further enhanced neuroprotection caused by hypoxic preconditioning. Taken together, the results confirm that autophagy is a protective response against ethanol neurotoxicity and the modest hypoxic preconditioning can offer neuroprotection by activating autophagic pathways. PMID:23568540

  7. IP Reassembly The ip_local_deliver() function, defined in net/ipv4/ip_input.c, is called by ip_rcv_finish.(). Its

    E-print Network

    Westall, James M.

    IP Reassembly The ip_local_deliver() function, defined in net/ipv4/ip_input.c, is called by ip_rcv_finish.(). Its function is: · to reassemble IP fragments that are destined for this host and · to call ip_local_deliver_finish () to deliver a complete packet to transport layer. 260 /* 261 * Deliver IP Packets to the higher protocol

  8. Hypoxic Preconditioning Differentially Affects GABAergic and Glutamatergic Neuronal Cells in the Injured Cerebellum of the Neonatal Rat

    PubMed Central

    Patterson, Sean I.; Muñoz, Estela M.; Seltzer, Alicia M.

    2014-01-01

    In this study we examined cerebellar alterations in a neonatal rat model of hypoxic-ischemic brain injury with or without hypoxic preconditioning (Pc). Between postnatal days 7 and 15, the cerebellum is still undergoing intense cellular proliferation, differentiation and migration, dendritogenesis and synaptogenesis. The expression of glutamate decarboxylase 1 (GAD67) and the differentiation factor NeuroD1 were examined as markers of Purkinje and granule cells, respectively. We applied quantitative immunohistochemistry to sagittal cerebellar slices, and Western blot analysis of whole cerebella obtained from control (C) rats and rats submitted to Pc, hypoxia-ischemia (L) and a combination of both treatments (PcL). We found that either hypoxia-ischemia or Pc perturbed the granule cells in the posterior lobes, affecting their migration and final placement in the internal granular layer. These effects were partially attenuated when the Pc was delivered prior to the hypoxia-ischemia. Interestingly, whole nuclear NeuroD1 levels in Pc animals were comparable to those in the C rats. However, a subset of Purkinje cells that were severely affected by the hypoxic-ischemic insult—showing signs of neuronal distress at the levels of the nucleus, cytoplasm and dendritic arborization—were not protected by Pc. A monoclonal antibody specific for GAD67 revealed a three-band pattern in cytoplasmic extracts from whole P15 cerebella. A ?110 kDa band, interpreted as a potential homodimer of a truncated form of GAD67, was reduced in Pc and L groups while its levels were close to the control animals in PcL rats. Additionally we demonstrated differential glial responses depending on the treatment, including astrogliosis in hypoxiated cerebella and a selective effect of hypoxia-ischemia on the vimentin-immunolabeled intermediate filaments of the Bergmann glia. Thus, while both glutamatergic and GABAergic cerebellar neurons are compromised by the hypoxic-ischemic insult, the former are protected by a preconditioning hypoxia while the latter are not. PMID:25032984

  9. Hypoxic preconditioning differentially affects GABAergic and glutamatergic neuronal cells in the injured cerebellum of the neonatal rat.

    PubMed

    Benitez, Sergio G; Castro, Analía E; Patterson, Sean I; Muñoz, Estela M; Seltzer, Alicia M

    2014-01-01

    In this study we examined cerebellar alterations in a neonatal rat model of hypoxic-ischemic brain injury with or without hypoxic preconditioning (Pc). Between postnatal days 7 and 15, the cerebellum is still undergoing intense cellular proliferation, differentiation and migration, dendritogenesis and synaptogenesis. The expression of glutamate decarboxylase 1 (GAD67) and the differentiation factor NeuroD1 were examined as markers of Purkinje and granule cells, respectively. We applied quantitative immunohistochemistry to sagittal cerebellar slices, and Western blot analysis of whole cerebella obtained from control (C) rats and rats submitted to Pc, hypoxia-ischemia (L) and a combination of both treatments (PcL). We found that either hypoxia-ischemia or Pc perturbed the granule cells in the posterior lobes, affecting their migration and final placement in the internal granular layer. These effects were partially attenuated when the Pc was delivered prior to the hypoxia-ischemia. Interestingly, whole nuclear NeuroD1 levels in Pc animals were comparable to those in the C rats. However, a subset of Purkinje cells that were severely affected by the hypoxic-ischemic insult--showing signs of neuronal distress at the levels of the nucleus, cytoplasm and dendritic arborization--were not protected by Pc. A monoclonal antibody specific for GAD67 revealed a three-band pattern in cytoplasmic extracts from whole P15 cerebella. A ?110 kDa band, interpreted as a potential homodimer of a truncated form of GAD67, was reduced in Pc and L groups while its levels were close to the control animals in PcL rats. Additionally we demonstrated differential glial responses depending on the treatment, including astrogliosis in hypoxiated cerebella and a selective effect of hypoxia-ischemia on the vimentin-immunolabeled intermediate filaments of the Bergmann glia. Thus, while both glutamatergic and GABAergic cerebellar neurons are compromised by the hypoxic-ischemic insult, the former are protected by a preconditioning hypoxia while the latter are not. PMID:25032984

  10. IP version 6IP version 6 --IP Next Generation (IPng)IP Next Generation (IPng)

    E-print Network

    Yeom, Ikjun

    Apr 1996 1933 Transition mechanisms for IPv6 hosts and routers Apr 1996 #12;3 IPng Considerations spaces. ­ it is general practice to assign a unique network number to an IP network whetherLabel PayloadLen NextHeader HopLimit SourceAddress DestinationAddress 0 4 12 16 24 31 Next header/data #12

  11. Voice Over IP Curriculum

    NSDL National Science Digital Library

    The Convergence Technology Center has made Voice over IP curriculum available online. The site includes a syllabus and learning activities related to the topic. If you are an educator who would like to gain full access to the complete curriculum, you may email convergence_technology@collin.edu (further instructions for access are available on the site).

  12. H(curl) Auxiliary Mesh Preconditioning

    SciTech Connect

    Kolev, T V; Pasciak, J E; Vassilevski, P S

    2006-08-31

    This paper analyzes a two-level preconditioning scheme for H(curl) bilinear forms. The scheme utilizes an auxiliary problem on a related mesh that is more amenable for constructing optimal order multigrid methods. More specifically, we analyze the case when the auxiliary mesh only approximately covers the original domain. The latter assumption is important since it allows for easy construction of nested multilevel spaces on regular auxiliary meshes. Numerical experiments in both two and three space dimensions illustrate the optimal performance of the method.

  13. Domain-decomposed preconditionings for transport operators

    NASA Technical Reports Server (NTRS)

    Chan, Tony F.; Gropp, William D.; Keyes, David E.

    1991-01-01

    The performance was tested of five different interface preconditionings for domain decomposed convection diffusion problems, including a novel one known as the spectral probe, while varying mesh parameters, Reynolds number, ratio of subdomain diffusion coefficients, and domain aspect ratio. The preconditioners are representative of the range of practically computable possibilities that have appeared in the domain decomposition literature for the treatment of nonoverlapping subdomains. It is shown that through a large number of numerical examples that no single preconditioner can be considered uniformly superior or uniformly inferior to the rest, but that knowledge of particulars, including the shape and strength of the convection, is important in selecting among them in a given problem.

  14. Biological networks in ischemic tolerance - Rethinking the approach to clinical conditioning

    PubMed Central

    Anrather, Josef; Hallenbeck, John M.

    2013-01-01

    The adaptive response (conditioning) to environmental stressors evokes evolutionarily conserved programs in uni- and multicellular organisms that result in increased fitness and resistance to stressor induced injury. Although the concept of conditioning has been around for a while, its translation into clinical therapies targeting neurovascular diseases has only recently begun. The slow pace of clinical adoption might be partially explained by our poor understanding of underpinning mechanisms and of the complex responses of the organism to the stressor. At the 2nd Translational Preconditioning Meeting participants engaged in an intense discussion addressing whether the time has come to more aggressively implement clinical conditioning protocols in the treatment of cerebrovascular diseases or whether it would be better to wait until preclinical data would help to minimize clinical empiricism. This review addresses the complex involvement of biological networks in establishing ischemic tolerance at the organism level using two clinically promising conditioning modalities, namely remote ischemic preconditioning, and per- or post-conditioning, as examples. PMID:24223074

  15. CISCO IP 7902 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7902 FONCTIONS T�L�PHONIQUES FONCTIONS DE BASE FAIRE UN APPEL Soulever le combiné et participants. Mettre un terme à une conférence Raccrocher le combiné. . Cisco_IP_7902_FR_CM%207.0_2009324[1].doc 1 de 2 #12;CISCO IP 7902 FONCTIONS T�L�PHONIQUES Cisco_IP_7902_FR_CM%207.0_2009324[1].doc 2 de 2

  16. Ocular ischemic syndrome and ischemic optic neuropathy in Takayasu arteritis.

    PubMed

    Malik, Tayyaba Gul; Khalil, Muhammad; Ijaz, Asad Ullah; Bhatti, Muhammad Moeen

    2015-04-01

    Ocular Ischemic Syndrome (OIS) is a disorder, which consists of constellation of signs and symptoms secondary to chronic ocular hypoperfusion. We report a case of 35 years old Pakistani female who presented to us with gradual fall of vision in both eyes. On examination, she had bilateral OIS and ischemic optic neuropathy. The patient had past history of transient ischemic attack and facial palsy almost 20 years back. We referred her to physician for the diagnosis of Takayasu arteritis associated with relapsing polychondritis. She was given 60 mg of dexamethasone per day as initial treatment. At her last follow-up after approximately 3 months, she was quite comfortable systemically and her general condition was improved. Unfortunately, her vision did not improve. These two autoimmune diseases are rarely reported together in the same patient in Pakistan. Whether this association is rare or is underdiagnosed still remains to be answered. PMID:25933464

  17. Preconditioned Multigrid Methods for Compressible Flow Calculations on Stretched Meshes

    Microsoft Academic Search

    Niles A. Pierce; Michael B. Giles

    1997-01-01

    Efficient preconditioned multigrid methods are developed for both inviscid and viscous flow applications. The work is motivated by the mixed results obtained using the standard approach of scalar preconditioning and full coarsened multigrid, which performs well for Euler calculations on moderately stretched meshes but is far less effective for turbulent Naiver–Stokes calculations, when the cell stretching becomes severe. In the

  18. Analysis and design of preconditioning methods for the Euler equations

    Microsoft Academic Search

    Marco Rodolfo Zaccanti

    1999-01-01

    Preconditioning of a system of equations at the differential level represents a relatively new area of research in convergence acceleration of discrete schemes for the fluid dynamics equations. This technique attempts to remove the intrinsic stiffness of the equations caused by the different time scales of the dynamic problem. Specifically, for the Euler equations, preconditioning aims at equalizing the speed

  19. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Preconditioning for tests. 183.220 Section 183...220 Preconditioning for tests. A boat must meet the following...at least 18 hours before the tests required by §§ 183.225...the motor and controls and the battery in lieu of this...

  20. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Preconditioning for tests. 183.220 Section 183...220 Preconditioning for tests. A boat must meet the following...at least 18 hours before the tests required by §§ 183.225...the motor and controls and the battery in lieu of this...

  1. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Preconditioning for tests. 183.220 Section 183...220 Preconditioning for tests. A boat must meet the following...at least 18 hours before the tests required by §§ 183.225...the motor and controls and the battery in lieu of this...

  2. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... false Preconditioning for tests. 183.220 Section 183...220 Preconditioning for tests. A boat must meet the following...at least 18 hours before the tests required by §§ 183.225...the motor and controls and the battery in lieu of this...

  3. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Preconditioning for tests. 183.220 Section 183...220 Preconditioning for tests. A boat must meet the following...at least 18 hours before the tests required by §§ 183.225...the motor and controls and the battery in lieu of this...

  4. Modern Preconditioned Eigensolvers for Spectral Image Segmentation and Graph Bisection

    E-print Network

    Knyazev, Andrew

    Modern Preconditioned Eigensolvers for Spectral Image Segmentation and Graph Bisection Workshop numerical solution of eigenvalue problems with the graph Laplacian. We discuss several modern preconditioned Innovation Center through the joint "Approaches to Combat Terrorism" Program Solicitation NSF 03-569. 1

  5. IP contains basic observations or

    E-print Network

    IP contains basic observations or measurements (data) in static form (e.g., tables, figures.g., metadata). IP contains any of the following: new methods for data acquisition or processing; stated data or analyses of data; extrapolation from data to predictions. IP presents new original data

  6. Vasoconstrictive neurovascular coupling during focal ischemic depolarizations

    E-print Network

    Boas, David

    Vasoconstrictive neurovascular coupling during focal ischemic depolarizations Hwa Kyoung Shin1 and Neurovascular Regulation Laboratory, Massachusetts General Hospital, Harvard Medical School, Charlestown lesion development in ischemic mouse brain. Mitigating the vasoconstrictive neurovascular coupling during

  7. Sonographic diagnosis of ischemic colitis.

    PubMed

    Ranschaert, E; Verhille, R; Marchal, G; Rigauts, H; Ponette, E

    1994-08-01

    An abdominal ultrasound examination performed on two patients with abdominal pain showed segmental wall thickening of the colon that proved to be due to ischemic colitis. In one case, the typical "target lesion" was recognized. These findings could be confirmed with computed tomography, whereas a single contrast enema was unable to demonstrate the ischemic disease. In the second case, a typical five-layered structure of the bowel wall could be demonstrated. It is concluded that US can be useful in the early diagnosis of colonic ischemia. PMID:7961360

  8. [Antioxidant therapy in ischemic stroke].

    PubMed

    Suslina, Z A; Federova, T N; Maksimova, M Iu; Riasina, T V; Stvolinski?, S L; Khrapova, E V; Boldyrev, A A

    2000-01-01

    The paper presents the results of investigation of emoxipin, an antioxidant synthetic drug, for treatment of patients with ischemic disorders of cerebral circulation. The drug produced a beneficial clinical effect in patients with lacunar and cardioembolic strokes of moderate severity. Therapy with emoxipin increased endogenic antioxidant activity and improved a clinical status of the patients. The protective effect of carnosine was demonstrated in experimental acute hypobaric hypoxia and cerebral ischemia in rats. The results obtained permit to recommend an inclusion of both emoxipin and carnosine in a combined treatment of ischemic disorders of cerebral circulation. PMID:11081266

  9. Differential monocular vs. binocular pupil responses from melanopsin-based photoreception in patients with anterior ischemic optic neuropathy.

    PubMed

    Tsika, Chrysanthi; Crippa, Sylvain V; Kawasaki, Aki

    2015-01-01

    We examined the effect of anterior ischemic optic neuropathy (AION) on the activity of intrinsically photosensitive retinal ganglion cells (ipRGCs) using the pupil as proxy. Eighteen patients with AION (10 unilateral, 8 bilateral) and 29 age-matched control subjects underwent chromatic pupillometry. Red and blue light stimuli increasing in 0.5?log steps were presented to each eye independently under conditions of dark and light adaptation. The recorded pupil contraction was plotted against stimulus intensity to generate scotopic and photopic response curves for assessment of synaptically-mediated ipRGC activity. Bright blue light stimuli presented monocularly and binocularly were used for melanopsin activation. The post-stimulus pupil size (PSPS) at the 6th second following stimulus offset was the marker of intrinsic ipRGC activity. Finally, questionnaires were administered to assess the influence of ipRGCs on sleep. The pupil response and PSPS to all monocularly-presented light stimuli were impaired in AION eyes, indicating ipRGC dysfunction. To binocular light stimulation, the PSPS of AION patients was similar to that of controls. There was no difference in the sleep habits of the two groups. Thus after ischemic injury to one or both optic nerves, the summated intrinsic ipRGC activity is preserved when both eyes receive adequate light exposure. PMID:26074032

  10. Differential monocular vs. binocular pupil responses from melanopsin-based photoreception in patients with anterior ischemic optic neuropathy

    PubMed Central

    Tsika, Chrysanthi; Crippa, Sylvain V.; Kawasaki, Aki

    2015-01-01

    We examined the effect of anterior ischemic optic neuropathy (AION) on the activity of intrinsically photosensitive retinal ganglion cells (ipRGCs) using the pupil as proxy. Eighteen patients with AION (10 unilateral, 8 bilateral) and 29 age-matched control subjects underwent chromatic pupillometry. Red and blue light stimuli increasing in 0.5?log steps were presented to each eye independently under conditions of dark and light adaptation. The recorded pupil contraction was plotted against stimulus intensity to generate scotopic and photopic response curves for assessment of synaptically-mediated ipRGC activity. Bright blue light stimuli presented monocularly and binocularly were used for melanopsin activation. The post-stimulus pupil size (PSPS) at the 6th second following stimulus offset was the marker of intrinsic ipRGC activity. Finally, questionnaires were administered to assess the influence of ipRGCs on sleep. The pupil response and PSPS to all monocularly-presented light stimuli were impaired in AION eyes, indicating ipRGC dysfunction. To binocular light stimulation, the PSPS of AION patients was similar to that of controls. There was no difference in the sleep habits of the two groups. Thus after ischemic injury to one or both optic nerves, the summated intrinsic ipRGC activity is preserved when both eyes receive adequate light exposure. PMID:26074032

  11. Transient ischemic attacks: predictability of future ischemic stroke or transient ischemic attack events

    PubMed Central

    Gupta, Harsh V; Farrell, Ann M; Mittal, Manoj K

    2014-01-01

    The short-term risk of an ischemic stroke after a transient ischemic attack (TIA) is estimated to be approximately 3%–10% at 2 days, 5% at 7 days, and 9%–17% at 90 days, depending on active or passive ascertainment of ischemic stroke. Various risk prediction scores are available to identify high-risk patients. We present here a pragmatic review of the literature discussing the main scoring systems. We also provide the sensitivity, specificity, positive predictive value, and negative predictive value for each scoring system. Our review shows that scoring systems including brain imaging and vascular imaging are better at risk prediction than scores that do not include this information. PMID:24476667

  12. IP Layer Input Packet Processing The receive functions of the IP layer include

    E-print Network

    Westall, James M.

    IP Layer Input Packet Processing The receive functions of the IP layer include: · IP header validation; · IP header option processing; · Reassembly of fragmented packets; · Routing of the input packet_buff. This the primary concern of the ip_rcv() function which is defined in net/ipv4/ip_input.c. 370 /* 371 * Main IP

  13. The preconditioning of major sudden stratospheric warmings

    NASA Astrophysics Data System (ADS)

    Bancalá, S.; Krüger, K.; Giorgetta, M.

    2012-02-01

    The preconditioning of major sudden stratospheric warmings (SSWs) is investigated with two long time series using reanalysis (ERA-40) and model (MAECHAM5/MPI-OM) data. Applying planetary wave analysis, we distinguish between wavenumber-1 and wavenumber-2 major SSWs based on the wave activity of zonal wavenumbers 1 and 2 during the prewarming phase. For this analysis an objective criterion to identify and classify the preconditioning of major SSWs is developed. Major SSWs are found to occur with a frequency of six and seven events per decade in the reanalysis and in the model, respectively, thus highlighting the ability of MAECHAM5/MPI-OM to simulate the frequency of major SSWs realistically. However, from these events only one quarter are wavenumber-2 major warmings, representing a low (˜0.25) wavenumber-2 to wavenumber-1 major SSW ratio. Composite analyses for both data sets reveal that the two warming types have different dynamics; while wavenumber-1 major warmings are preceded only by an enhanced activity of the zonal wavenumber-1, wavenumber-2 events are either characterized by only the amplification of zonal wavenumber-2 or by both zonal wavenumber-1 and zonal wavenumber-2, albeit at different time intervals. The role of tropospheric blocking events influencing these two categories of major SSWs is evaluated in the next step. Here, the composite analyses of both reanalysis and model data reveal that blocking events in the Euro-Atlantic sector mostly lead to the development of wavenumber-1 major warmings. The blocking-wavenumber-2 major warming connection can only be statistical reliable analyzed with the model time series, demonstrating that blocking events in the Pacific region mostly precede wavenumber-2 major SSWs.

  14. Glutamate transporter type 3 mediates isoflurane preconditioning-induced acute phase of neuroprotection in mice

    PubMed Central

    Li, Liaoliao; Deng, Jiao; Zuo, Zhiyi

    2013-01-01

    A pre-exposure to isoflurane reduces ischemic brain injury in rodents (isoflurane preconditioning). This neuroprotection has acute and delayed phases. Our previous in vitro studies suggest that the acute phase may involve excitatory amino acid transporters (EAAT). We determine whether this protection involves EAAT3, the major neuronal EAAT. Adult male EAAT3 knockout mice and their wild-type littermates were exposed or were not exposed to 1.5% isoflurane for 30 min. Sixty minutes later, they were subjected to a 90- or 60-min middle cerebral arterial occlusion (MCAO). Their neurological outcomes were evaluated 24 h after the MCAO. In another experiment, cerebral cortex was harvested for Western blotting at 30 min after animals were exposed to 1.5% isoflurane for 30 min. Here, we showed that isoflurane reduced brain infarct volumes and improved neurological functions of wild-type mice after a 90-min MCAO. However, isoflurane pre-exposure did not change the neurological outcome of EAAT3 knockout mice no matter whether the MCAO was for 90 min or 60 min. Isoflurane increased phospho-Akt, a survival-promoting protein, in the wild-type mice but not in the EAAT3 knockout mice. The isoflurane-induced neuroprotection in the wild-type mice was abolished by LY294004, an Akt activation inhibitor. LY294004 alone did not affect the neurological outcome of the wild-type or EAAT3 knockout mice after focal brain ischemia. These results suggest that the isoflurane preconditioning-induced acute phase of neuroprotection involves EAAT3. The downstream event includes Akt activation. PMID:23827345

  15. Quantification of neurovascular protection following repetitive hypoxic preconditioning and transient middle cerebral artery occlusion in mice.

    PubMed

    Poinsatte, Katherine; Selvaraj, Uma Maheswari; Ortega, Sterling B; Plautz, Erik J; Kong, Xiangmei; Gidday, Jeffrey M; Stowe, Ann M

    2015-01-01

    Experimental animal models of stroke are invaluable tools for understanding stroke pathology and developing more effective treatment strategies. A 2 week protocol for repetitive hypoxic preconditioning (RHP) induces long-term protection against central nervous system (CNS) injury in a mouse model of focal ischemic stroke. RHP consists of 9 stochastic exposures to hypoxia that vary in both duration (2 or 4 hr) and intensity (8% and 11% O2). RHP reduces infarct volumes, blood-brain barrier (BBB) disruption, and the post-stroke inflammatory response for weeks following the last exposure to hypoxia, suggesting a long-term induction of an endogenous CNS-protective phenotype. The methodology for the dual quantification of infarct volume and BBB disruption is effective in assessing neurovascular protection in mice with RHP or other putative neuroprotectants. Adult male Swiss Webster mice were preconditioned by RHP or duration-equivalent exposures to 21% O2 (i.e. room air). A 60 min transient middle cerebral artery occlusion (tMCAo) was induced 2 weeks following the last hypoxic exposure. Both the occlusion and reperfusion were confirmed by transcranial laser Doppler flowmetry. Twenty-two hr after reperfusion, Evans Blue (EB) was intravenously administered through a tail vein injection. 2 hr later, animals were sacrificed by isoflurane overdose and brain sections were stained with 2,3,5- triphenyltetrazolium chloride (TTC). Infarcts volumes were then quantified. Next, EB was extracted from the tissue over 48 hr to determine BBB disruption after tMCAo. In summary, RHP is a simple protocol that can be replicated, with minimal cost, to induce long-term endogenous neurovascular protection from stroke injury in mice, with the translational potential for other CNS-based and systemic pro-inflammatory disease states. PMID:25993394

  16. Mathematical statistics. I and II exercise, week 28.9. -3.10. 2003. Below: = IP+ ~IP

    E-print Network

    Valkeila, Esko

    Mathematical statistics. I and II exercise, week 28.9. - 3.10. 2003. Below: µ = IP+ ~IP 2 , z = dIP dµ ja ~z = d ~IP µ . 1. Show that ~IP IP ~IP(z > 0) = 0 H(IP, ~IP; ) = 0 jollain (0, 1). 2. Show that ||IP - ~IP|| = 1 - IEµ min(z, ~z) and that ||IP - ~IP|| = 1 2 IEµ|z - ~z|. 3. Define the Kullback

  17. iPS cell sheets created by a novel magnetite tissue engineering method for reparative angiogenesis

    PubMed Central

    Kito, Tetsutaro; Shibata, Rei; Ishii, Masakazu; Suzuki, Hirohiko; Himeno, Tatsuhito; Kataoka, Yoshiyuki; Yamamura, Yumiko; Yamamoto, Takashi; Nishio, Naomi; Ito, Sachiko; Numaguchi, Yasushi; Tanigawa, Tohru; Yamashita, Jun K.; Ouchi, Noriyuki; Honda, Hiroyuki; Isobe, Kenichi; Murohara, Toyoaki

    2013-01-01

    Angiogenic cell therapy represents a novel strategy for ischemic diseases, but some patients show poor responses. We investigated the therapeutic potential of an induced pluripotent stem (iPS) cell sheet created by a novel magnetite tissue engineering technology (Mag-TE) for reparative angiogenesis. Mouse iPS cell-derived Flk-1+ cells were incubated with magnetic nanoparticle-containing liposomes (MCLs). MCL-labeled Flk-1+ cells were mixed with diluted extracellular matrix (ECM) precursor and a magnet was placed on the reverse side. Magnetized Flk-1+ cells formed multi-layered cell sheets according to magnetic force. Implantation of the Flk-1+ cell sheet accelerated revascularization of ischemic hindlimbs relative to the contralateral limbs in nude mice as measured by laser Doppler blood flow and capillary density analyses. The Flk-1+ cell sheet also increased the expressions of VEGF and bFGF in ischemic tissue. iPS cell-derived Flk-1+ cell sheets created by this novel Mag-TE method represent a promising new modality for therapeutic angiogenesis. PMID:23475393

  18. Voice over IP performance monitoring

    Microsoft Academic Search

    Robert G. Cole; J. H. Rosenbluth

    2001-01-01

    We describe a method for monitoring Voice over IP (VoIP) applications based upon a reduction of the ITU-T's E-Model to transport level, measurable quantities. In the process, 1) we identify the relevant transport level quantities, 2) we discuss the tradeoffs between placing the monitors within the VoIP gateways versus placement of the monitors within the transport path, and 3) we

  19. Preconditioning Outside Air: Cooling Loads from Building Ventilation 

    E-print Network

    Kosar, D.

    1998-01-01

    of the standard. To mitigate or nullify these additional weather loads, outdoor air preconditioning technologies are being promoted in combination with conventional HVAC operations downstream as a means to deliver the required fresh air and control humidity...

  20. Progress in Parallel Schur Complement Preconditioning for Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.; Chan, Tony F.; Tang, Wei-Pai; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We consider preconditioning methods for nonself-adjoint advective-diffusive systems based on a non-overlapping Schur complement procedure for arbitrary triangulated domains. The ultimate goal of this research is to develop scalable preconditioning algorithms for fluid flow discretizations on parallel computing architectures. In our implementation of the Schur complement preconditioning technique, the triangulation is first partitioned into a number of subdomains using the METIS multi-level k-way partitioning code. This partitioning induces a natural 2X2 partitioning of the p.d.e. discretization matrix. By considering various inverse approximations of the 2X2 system, we have developed a family of robust preconditioning techniques. A computer code based on these ideas has been developed and tested on the IBM SP2 and the SGI Power Challenge array using MPI message passing protocol. A number of example CFD calculations will be presented to illustrate and assess various Schur complement approximations.

  1. Preconditioned solenoidal basis method for incompressible fluid flows 

    E-print Network

    Wang, Xue

    2006-04-12

    This thesis presents a preconditioned solenoidal basis method to solve the algebraic system arising from the linearization and discretization of primitive variable formulations of Navier-Stokes equations for incompressible ...

  2. Attenuation of sensory preconditioning by noradrenaline depletion in the rat.

    PubMed

    Archer, T; Mohammed, A K; Danysz, W; Järbe, T U; Jonsson, G

    1986-04-01

    In order to investigate the effect of noradrenaline (NA) depletion upon an associative learning phenomenon, sensory preconditioning, rats were inflicted with either 6-hydroxydopamine-induced lesions of the dorsal noradrenergic bundle (DNAB) or the locus coeruleus (LC), or with systemic injections of the NA neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4). Using appropriate controls (the UP groups) sensory preconditioning was demonstrated clearly in the non-lesion conditions (Sham or saline), but was blocked or strongly attenuated in the DNAB and DSP4 conditions. LC lesions did not affect sensory preconditioning. These findings suggest that the loss of central NA may cause some disruption of some aspects of complex associative learning. The role of NA in sensory preconditioning may be relevant to current notions of NA function. PMID:3718664

  3. White Matter Ischemic Changes in Hyperacute Ischemic Stroke

    PubMed Central

    Trouard, Theodore P; Lafleur, Scott R.; Krupinski, Elizabeth A.; Salamon, Noriko; Kidwell, Chelsea S.

    2015-01-01

    Background and Purpose— The purpose of this study was to evaluate changes in fractional anisotropy (FA), as measured by diffusion tensor imaging, of white matter (WM) infarction and hypoperfusion in patients with acute ischemic stroke using a quantitative voxel-based analysis. Methods— In this prospective study, diffusion tensor imaging and dynamic susceptibility contrast perfusion sequences were acquired in 21 patients with acute ischemic stroke who presented within 6 hours of symptom onset. The coregistered FA, apparent diffusion coefficient, and dynamic susceptibility contrast time to maximum (Tmax) maps were used for voxel-based quantification using a region of interest approach in the ipsilateral affected side and in the homologous contralateral WM. The regions of WM infarction versus hypoperfusion were segmented using a threshold method. Data were analyzed by regression and ANOVA. Results— There was an overall significant mean difference (P<0.001) for the apparent diffusion coefficient, Tmax, and FA values between the normal, hypoperfused, and infarcted WM. The mean±SD of FA was significantly higher (P<0.001) in hypoperfused WM (0.397±0.019) and lower (P<0.001) in infarcted WM (0.313±0.037) when compared with normal WM (0.360±0.020). Regression tree analysis of hypoperfused WM showed the largest mean FA difference at Tmax above versus below 5.4 s with a mean difference of 0.033 (P=0.0096). Conclusions— Diffusion tensor imaging-FA was decreased in regions of WM infarction and increased in hypoperfused WM in patients with hyperacute acute ischemic stroke. The significantly increased FA values in the hypoperfused WM with Tmax?5.4 s are suggestive of early ischemic microstructural changes. PMID:25523053

  4. An optimised preconditioning procedure for gas permeability measurement

    Microsoft Academic Search

    M. Carcassès; A. Abbas; J.-P. Ollivier; J. Verdier

    2002-01-01

    To study the permeability of cementitious materials; a procedure of drying out moisture before the actual measurement of this\\u000a property, normally called preconditioning, is an unavoidable necessity. In this study, the preconditioning procedure developed\\u000a by the authors earlier, is used to carry out the measurement of permeability to gases of 15 concrete compositions in order\\u000a to compare the different steps

  5. Reactive Oxygen Species and Mitochondrial KATP Channels Mediate Helium-Induced Preconditioning Against Myocardial Infarction In Vivo

    PubMed Central

    Pagel, Paul S.; Krolikowski, John G.; Pratt, Phillip F.; Shim, Yon Hee; Amour, Julien; Warltier, David C.; Weihrauch, Dorothee

    2008-01-01

    Objectives Helium produces preconditioning by activating prosurvival kinases, but the roles of reactive oxygen species (ROS) or mitochondrial KATP channels in this process are unknown. We tested the hypothesis that ROS and mitochondrial KATP channels mediate helium-induced preconditioning in vivo. Design Randomized, prospective study. Setting University research laboratory. Participants Male New Zealand white rabbits. Interventions Rabbits (n=64) were instrumented for measurement of systemic hemodynamics and subjected to a 30 min left anterior descending coronary artery (LAD) occlusion and 3 h reperfusion. In separate experimental groups, rabbits (n=7 or 8 per group) were randomly assigned to receive 0.9% saline (control) or three cycles of 70% helium-30% oxygen administered for 5 min interspersed with 5 min of an air-oxygen mixture before LAD occlusion with or without the ROS scavengers N-acetylcysteine (NAC; 150 mg/kg) or N-2-mercaptoproprionyl glycine (2-MPG; 75 mg/kg), or the mitochondrial KATP antagonist 5-hydroxydecanoate (5-HD; 5 mg/kg). Statistical analysis of data was performed with analysis of variance for repeated measures followed by Bonferroni's modification of Student's t test. Measurements and Main Results Myocardial infarct size was determined using triphenyltetrazolium chloride staining and presented as a percentage of the left ventricular area at risk. Helium significantly (P<0.05) reduced infarct size (23±4% of the area at risk; mean±SD) compared with control (46±3%). NAC, 2-MPG, and 5-HD did not affect irreversible ischemic injury when administered alone (49±5, 45±6, and 45±3%), but these drugs blocked reductions in infarct size produced by helium (45±4, 45±2, and 44±3%). Conclusions The results suggest that ROS and mitochondrial KATP channels mediate helium-induced preconditioning in vivo. PMID:18662630

  6. The Galvanotactic Migration of Keratinocytes is Enhanced by Hypoxic Preconditioning

    PubMed Central

    Guo, Xiaowei; Jiang, Xupin; Ren, Xi; Sun, Huanbo; Zhang, Dongxia; Zhang, Qiong; Zhang, Jiaping; Huang, Yuesheng

    2015-01-01

    The endogenous electric field (EF)-directed migration of keratinocytes (galvanotaxis) into wounds is an essential step in wound re-epithelialization. Hypoxia, which occurs immediately after injury, acts as an early stimulus to initiate the healing process; however, the mechanisms for this effect, remain elusive. We show here that the galvanotactic migration of keratinocytes was enhanced by hypoxia preconditioning as a result of the increased directionality rather than the increased motility of keratinocytes. This enhancement was both oxygen tension- and preconditioning time-dependent, with the maximum effects achieved using 2% O2 preconditioning for 6?hours. Hypoxic preconditioning (2% O2, 6?hours) decreased the threshold voltage of galvanotaxis to?preconditioning accelerated healing by 1.38-fold compared with the control conditions. Scavenging of the induced ROS by N-acetylcysteine (NAC) abolished the enhanced galvanotaxis and the accelerated healing by hypoxic preconditioning. Our data demonstrate a novel and unsuspected role of hypoxia in supporting keratinocyte galvanotaxis. Enhancing the galvanotactic response of cells might therefore be a clinically attractive approach to induce improved wound healing. PMID:25988491

  7. Analysis and design of preconditioning methods for the Euler equations

    NASA Astrophysics Data System (ADS)

    Zaccanti, Marco Rodolfo

    Preconditioning of a system of equations at the differential level represents a relatively new area of research in convergence acceleration of discrete schemes for the fluid dynamics equations. This technique attempts to remove the intrinsic stiffness of the equations caused by the different time scales of the dynamic problem. Specifically, for the Euler equations, preconditioning aims at equalizing the speed of propagation of the different waves of the hyperbolic problem. This 'fix' becomes particularly useful in the incompressible limit and in the neighborhood of the sonic point. Practical examples of application of preconditioning include modern transonic supercritical airfoils, and nearly incompressible flows with embedded regions where compressibility is important (e.g., low speed combustion). This study attempts the ambitious project of reviewing most of the work done in Euler preconditioning, while at the same time extending some of the existing methods and correcting their robustness problems. Several original contributions to the theory of Euler preconditioning are given, including a thorough exposition of the symmetrizability property of the preconditioned equations, a discussion of the positive definiteness property of the preconditioning matrix, and the study of the eigenvalues for the full form of the preconditioner. Considering the numerical implementation of the preconditioned methods using the Roe flux function, a scheme based on the classical one-Riemann problem normal to the cell interface is proposed, and its advantages over other formulations found in the literature, as well as its drawbacks, are discussed. Then, the analysis of several existing preconditioning methods is conducted, and the complete eigenvector structure of the equations preconditioned with the Van Leer- Lee-Roe matrix, the Turkel matrix, the Choi-Merkle matrix, and a few others, is obtained and analyzed. A comprehensive exploration of preconditioning in one and two spatial dimensions is attempted, which allows to better understand the properties of existing preconditioners. While this investigation suggests new interesting families of one-dimensional preconditioners, for the two-dimensional case the analysis is complete only for the sparse form of the preconditioner, and shows that in this instance it is not possible to remove all of the robustness problems usually found in Euler preconditioning. When considering the full form of the preconditioning matrix the analysis is not complete, because of the formidable algebraic problem involved. Nonetheless, some specific solutions are considered, and a few general conclusions are also drawn in this case. Finally, it is shown that there exist at least two sparse preconditioners that are sufficiently robust in computing stagnation point flow, while preserving the overall effectiveness of preconditioning for low speed flow. One of these matrices is a modification of the popular Turkel method. Using this matrix in regions of low Mach number, in conjunction with the Van Leer-Lee-Roe preconditioner in the transonic and supersonic parts of the flow field, allows to achieve a very robust and efficient preconditioning procedure for the entire Mach regime.

  8. Therapeutic Strategy for Ischemic Stroke

    Microsoft Academic Search

    Toru Yamashita; Kentaro Deguchi; Yoshihide Sehara; Violeta Lukic-Panin; Hanzhe Zhang; Tatsushi Kamiya; Koji Abe

    2009-01-01

    Possible strategies for treating ischemic stroke include: (1) Neuroprotection: preventing damaged neurons from undergoing\\u000a apoptosis in the acute phase of cerebral ischemia; (2) Stem cell therapy: the repair of broken neuronal networks with newly\\u000a born neurons in the chronic phase of cerebral ischemia. Firstly, we studied the neuroprotective effect of a calcium channel\\u000a blocker, azelnidipine, or a by-product of heme

  9. Mobility management in mobile IP

    Microsoft Academic Search

    Sirisha Medidi; Forouzan Golshani

    2002-01-01

    There is an emerging interest in integrating mobile wireless communication with the Internet based on the Ipv6 technology. Many issues introduced by the mobility of users arise when such an integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current IP addresses of mobile terminals and sustaining active IP connections as mobiles move.

  10. Hash-based IP traceback

    Microsoft Academic Search

    Alex C. Snoeren; Craig Partridge; Luis A. Sanchez; Christine E. Jones; Fabrice Tchakountio; Stephen T. Kent; W. Timothy Strayer

    2001-01-01

    The design of the IP protocol makes it difficult to reliably identify the originator of an IP packet. Even in the absence of any deliberate attempt to disguise a packet's origin, wide-spread packet forwarding techniques such as NAT and encapsulation may obscure the packet's true source. Techniques have been developed to determine the source of large packet flows, but, to

  11. Voice Over IP Reference Page

    NSDL National Science Digital Library

    This site is a collection of architectural specifications, network and signaling protocols, and technical papers related to virtually every aspect of VoIP. Detailed articles and standards information are regularly updated on the site. There is also a collection of documents containing VoIP references, and in this sections, visitors will find an H.323 tutorial.

  12. IP Addresses in Email Clients

    Microsoft Academic Search

    Joshua Goodman

    2004-01-01

    Abstract. IP addresses are an important tool for fighting spam, used for safe lists, blackhole lists, anti-spoofing and related purposes. While it is trivial to find the sender's IP address in most email server software, it turns out to be surprisingly di cult to do so in email client software: we explain why. This implies that either alternative approaches are

  13. Acute ischemic coronary artery disease and ischemic stroke: similarities and differences

    Microsoft Academic Search

    Marc Fisher; Edward Folland

    2008-01-01

    Although acute myocardial infarction (MI) and acute ischemic stroke share similarities, physicians need to recognize important differences in pathophysiology and how these differences affect acute treatment and prevention to provide optimal patient care. Potential causes of acute ischemic stroke are substantially more heterogeneous than for acute MI, and available acute therapies are substantially more limited. In acute ischemic stroke patients,

  14. Echocardiographic assessment of ischemic mitral regurgitation.

    PubMed

    Dudzinski, David M; Hung, Judy

    2014-01-01

    Ischemic mitral regurgitation is an important consequence of LV remodeling after myocardial infarction. Echocardiographic diagnosis and assessment of ischemic mitral regurgitation are critical to gauge its adverse effects on prognosis and to attempt to tailor rational treatment strategy. There is no single approach to the echocardiographic assessment of ischemic mitral regurgitation: standard echocardiographic measures of mitral regurgitation severity and of LV dysfunction are complemented by assessments of displacement of the papillary muscles and quantitative indices of mitral valve deformation. Development of novel approaches to understand mitral valve geometry by echocardiography may improve understanding of the mechanism, clinical trajectory, and reparability of ischemic mitral regurgitation. PMID:25416497

  15. Hyperbaric oxygen preconditioning attenuates hyperglycemia-enhanced hemorrhagic transformation by inhibiting matrix metalloproteinases in focal cerebral ischemia in rats

    PubMed Central

    Soejima, Yoshiteru; Hu, Qin; Krafft, Paul R.; Fujii, Mutsumi; Tang, Jiping; Zhang, John H.

    2013-01-01

    Hyperglycemia dramatically aggravates brain infarct and hemorrhagic transformation (HT) after ischemic stroke. Oxidative stress and matrix metalloproteinases (MMPs) play an important role in the pathophysiology of HT. Hyperbaric oxygen preconditioning (HBO-PC) has been proved to decrease oxidative stress and be neuroprotective in experimental stroke models. The present study determined whether HBO-PC would ameliorate HT by a pre-ischemic increase of reactive oxygen species (ROS) generation, and a suppression of MMP-2 and MMP-9 in hyperglycemic middle cerebral artery occlusion (MCAO) rats. Rats were pretreated with HBO (100% O2, 2.5 atmospheres absolute) 1 h daily for 5 days before MCAO. Acute hyperglycemia was induced by an injection of 50% dextrose. Neurological deficits, infarction volume and hemorrhagic volume were assessed 24 h and 7 days after ischemia. ROS scavenger n-acetyl cysteine (NAC), hypoxia-inducible factor-1? (HIF-1?) inhibitor 2-methoxyestradiol (2ME2) and activator cobalt chloride (CoCl2), and MMPs inhibitor SB-3CT were administrated for mechanism study. The activity of MMP-2 and MMP-9, and the expression HIF-1? were measured. HBO-PC improved neurological deficits, and reduced hemorrhagic volume; the expression of HIF-1? was significantly decreased, and the activity of MMP-2 and MMP-9 was reduced by HBO-PC compared with vehicle group. Our results suggested that HBO-PC attenuated HT via decreasing HIF-1? and its downstream MMP-2 and MMP-9 in hyperglycemic MCAO rats. PMID:23537951

  16. Mitochondrial reactive oxygen species: A double edged sword in ischemia/reperfusion vs preconditioning

    PubMed Central

    Kalogeris, Theodore; Bao, Yimin; Korthuis, Ronald J.

    2014-01-01

    Reductions in the blood supply produce considerable injury if the duration of ischemia is prolonged. Paradoxically, restoration of perfusion to ischemic organs can exacerbate tissue damage and extend the size of an evolving infarct. Being highly metabolic organs, the heart and brain are particularly vulnerable to the deleterious effects of ischemia/reperfusion (I/R). While the pathogenetic mechanisms contributing to I/R-induced tissue injury and infarction are multifactorial, the relative importance of each contributing factor remains unclear. However, an emerging body of evidence indicates that the generation of reactive oxygen species (ROS) by mitochondria plays a critical role in damaging cellular components and initiating cell death. In this review, we summarize our current understanding of the mechanisms whereby mitochondrial ROS generation occurs in I/R and contributes to myocardial infarction and stroke. In addition, mitochondrial ROS have been shown to participate in preconditioning by several pharmacologic agents that target potassium channels (e.g., ATP-sensitive potassium (mKATP) channels or large conductance, calcium-activated potassium (mBKCa) channels) to activate cell survival programs that render tissues and organs more resistant to the deleterious effects of I/R. Finally, we review novel therapeutic approaches that selectively target mROS production to reduce postischemic tissue injury, which may prove efficacious in limiting myocardial dysfunction and infarction and abrogating neurocognitive deficits and neuronal cell death in stroke. PMID:24944913

  17. Hyperbaric oxygen preconditioning attenuates hemorrhagic transformation through increasing PPAR? in hyperglycemic MCAO rats.

    PubMed

    Bian, Hetao; Hu, Qin; Liang, Xiping; Chen, Di; Li, Bo; Tang, Jiping; Zhang, John H

    2015-03-01

    Hyperbaric oxygen preconditioning (HBO-PC) has been demonstrated to attenuate hemorrhagic transformation (HT) after middle cerebral artery occlusion (MCAO) in hyperglycemic rats. However, the mechanisms remain to be illustrated. Recently, HBO-PC has been shown to activate peroxisome proliferator-activated receptor-gamma (PPAR?) by increasing 15d-PGJ2 in primary cultured neurons. We hypothesize that HBO-PC reduces HT by suppressing inflammation through increasing 15d-PGJ2 and activating PPAR? in hyperglycemic MCAO rats. HBO (2.5ATA) was administered for 1h daily for 5 consecutive days. The PPAR? inhibitor GW9662 was administered intraperitoneally to designated animals. Infarction volume, hemorrhage volume, neurological scores and mortality were analyzed. The levels of 15d-PGJ2, PPAR?, TNF-? and IL-1?, tight junction proteins as well as the activity of MMP-2 and MMP-9 were evaluated 24h after MCAO. HBO-PC reduced HT, improved neurological function, down-regulated inflammatory molecules and inhibited the activation of MMP-9 by increasing 15d-PGJ2 and PPAR? at 24h after MCAO. The results suggested that HBO-PC might be an alternative measure to decrease HT in ischemic stroke. PMID:25542160

  18. The impact of experimental preconditioning using vascular endothelial growth factor in stroke and subarachnoid hemorrhage.

    PubMed

    Eicker, Sven Oliver; Hoppe, Moritz; Etminan, Nima; Macht, Stephan; Perrin, Jason; Steiger, Hans-Jakob; Hänggi, Daniel

    2013-01-01

    Vascular endothelial growth factor (VEGF) stimulating angiogenesis was shown to be a potential novel therapeutic approach for the treatment of ischemic vascular diseases. The goal of the present study was to examine whether transfection of VEGF before occurrence of major stroke (part I) and cerebral vasospasm after experimental subarachnoid hemorrhage (SAH; part II) develops neuroprotective qualities. A total of 25 (part I) and 26 (part II) brains were analyzed, respectively. In part one, a significant reduction of infarct volume in the VEGF-treated stroke animals (43% reduction, P < 0.05) could be detected. In part two, significant vasospasm was induced in all hemorrhage groups (P < 0.02). Analyzing microperfusion, a significant higher amount of perfused vessels could be detected (P < 0.01), whereas no significant effect could be detected towards macroperfusion. Histologically, no infarctions were observed in the VEGF-treated SAH group and the sham-operated group. Minor infarction in terms of vasospasm-induced small lesions could be detected in the control vector transduced group (P = 0.05) and saline-treated group (P = 0.09). The present study demonstrates the preconditioning impact of systemic intramuscular VEGF injection in animals after major stroke and induced severe vasospasm after SAH. PMID:23634319

  19. Genetic Deletion of Prostacyclin IP Receptor Exacerbates Transient Global Cerebral Ischemia in Aging Mice

    PubMed Central

    Shakil, Hania; Saleem, Sofiyan

    2013-01-01

    Transient global cerebral ischemia causes delayed neuronal death in the hippocampal CA1 region. It also induces an up regulation of cyclooxygenase 2 (COX-2), which generates several metabolites of arachidonic acid, known as prostanoids, including Prostaglandin I2 (PGI2). The present study investigated whether the PGI2 IP receptor plays an important role in brain injury after global cerebral ischemia in aged mice. Adult young (2–3 months) and aged (12–15 months) male C57Bl/6 wild-type (WT) or IP receptor knockout (IP KO) mice underwent a 12 min bilateral common carotid artery occlusion (BCCAO) or a sham surgery. Behavior tests (neurologic deficit and T-maze) were performed 3 and 7 days after BCCAO. After seven days of reperfusion, the numbers of cells positive for markers of neurons, astrocytes, microglia, myeloperoxidase (MPO) and phosphorylated CREB (p-CREB) were evaluated immunohistochemically. Interestingly, in young and aged IP KO ischemic mice, there was a significant increase (p < 0.01) in cognitive deficit, hippocampal CA1 pyramidal neuron death, microglia and MPO activation, while p-CREB was reduced as compared to their corresponding WT controls. These data suggest that following ischemia, IP receptor deletion contributes to memory and cognitive deficits regulated by the CREB pathway and that treatment with IP receptor agonists could be a useful target to prevent harmful consequences. PMID:24634780

  20. [Morpho-functional changes of the pyramidal neurons in various hippocampal areas after the ischemic postconditioning].

    PubMed

    Shcherbak, N S; Galagudza, M M; Yukina, G Yu; Barantsevich, Ye R; Tomson, V V; Shlyako, Y V

    2013-01-01

    The aim of this study was to determine the effect of ischemic postconditioning (IP) on the viability of neurons in various hippocampal areas as well as on cytoplasmic activity of succinatedehydrogenase (SDH) in these cells in 30 male Mongolian gerbils (Meriones unguiculatus). Ischemic brain injury was induced by bilateral common carotid artery occlusion for 7 min. IP protocol comprised 3 cycles of 15 s of reperfusion/15 s of ischemia. After reperfusion for 48 h, the morphometric analysis was conducted, and SDH cytoplasmic activity was assessed using quantitative histochemistry in the pyramidal neurons of the hippocampal areas CA1, CA2, CA3, CA4. The experiment has demonstrated that 7-minute-long ischemia resulted in a significant decrease in the number of viable neurons in CA1 area (up to 24%) and in the CA3 (to 56%) of the hippocampus; besides, it lead to the elevation of SDH activity in the cytoplasm of the neurons in all the hippocampal areas as compared to that in sham-operated animals. The application of IP significantly increased the number of viable neurons in CA1 (up to 52.9%, P<0,01) and in CA3 areas of the hippocampus(up to 88%, P<0,05), and it was accompanied by reduction of SDH activity in surviving neurons in all the hippocampal areas. PMID:24020177

  1. Inactivation of astroglial NF-?B promotes survival of retinal neurons following ischemic injury

    PubMed Central

    Dvoriantchikova, Galina; Barakat, David; Brambilla, Roberta; Agudelo, Christian; Hernandez, Eleut; Bethea, John R.; Shestopalov, Valery I.; Ivanov, Dmitry

    2009-01-01

    Reactive astrocytes have been implicated in neuronal loss following ischemic stroke. However, the molecular mechanisms associated with this process are yet to be fully elucidated. In this work, we tested the hypothesis that astroglial NF-?B, a key regulator of inflammatory responses, is a contributor to neuronal death following ischemic injury. We compared neuronal survival in the ganglion cell layer after retinal ischemia-reperfusion in wild type and in GFAP-I?B?-dn transgenic mice, where the NF-?B classical pathway is suppressed specifically in astrocytes. The GFAP-I?B?-dn mice showed significantly increased survival of neurons in the ganglion cell layer following ischemic injury as compared to WT littermates. Neuroprotection was associated with significantly reduced expression of pro-inflammatory genes, encoding Tnf-?, Ccl2 (Mcp1), Cxcl10 (IP10), Icam1, Vcam1, several subunits of NADPH oxidase and NO synthase in the retinas of GFAP-I?B?-dn mice. These data suggest that certain NF-?B-regulated pro-inflammatory and redox-active pathways are central to glial neurotoxicity induced by ischemic injury. The inhibition of these pathways in astrocytes may represent a feasible neuroprotective strategy for retinal ischemia and stroke. PMID:19614983

  2. Morphine reduces the threshold of helium preconditioning against myocardial infarction: the role of opioid receptors in rabbits

    PubMed Central

    Pagel, Paul S.; Krolikowski, John G.; Amour, Julien; Warltier, David C.; Weihrauch, Dorothee

    2015-01-01

    Objectives Brief, repetitive administration of helium before prolonged coronary artery occlusion and reperfusion protects myocardium against infarction. Opioid receptors mediate the cardioprotective effects of ischemic pre- and postconditioning, but whether these receptors also play a role in helium preconditioning is unknown. We tested the hypotheses that opioid receptors mediate helium preconditioning and that morphine (a ?1-opioid receptor agonist with ?1-opioid agonist properties) lowers the threshold of cardioprotection produced by helium in vivo. Design Randomized, prospective study. Setting University research laboratory. Participants Male New Zealand white rabbits. Interventions Rabbits (n=56) were instrumented for measurement of systemic hemodynamics and subjected to a 30 min left anterior descending coronary artery (LAD) occlusion and 3 h reperfusion. In separate experimental groups, rabbits (n=6 or 7 per group) received 0.9% saline (control), one or three cycles of 70% helium-30% oxygen administered for 5 min interspersed with 5 min of an air-oxygen mixture, morphine (0.1 mg/kg, i.v.), or the nonselective opioid antagonist naloxone (6 mg/kg, i.v.) before LAD occlusion. Other groups of rabbits received three cycles of helium or one cycle of helium plus morphine (0.1 mg/kg) in the absence or presence of naloxone (6 mg/kg) before ischemia and reperfusion. Statistical analysis of data was performed with analysis of variance for repeated measures followed by Bonferroni’s modification of Student’s t test. Measurements and Main Results Myocardial infarct size was determined using triphenyltetrazolium chloride staining and presented as a percentage of the left ventricular area at risk. Helium reduced myocardial infarct size in an exposure-related manner [36±6 (P>0.05) and 25±4% (P<0.05 versus control) for one and three cycles of helium, respectively; data are mean±SD] compared with control (44±7%). Morphine and naloxone alone did not affect infarct size (45±2 and 40±8%, respectively). The combination of one cycle of helium and morphine reduced infarct size (24±5%, P<0.05 versus control) to an equivalent degree as three cycles of helium. Naloxone pretreatment abolished cardioprotection produced by three cycles of helium (47±2%) and the combination of one cycle of helium plus morphine (45±4%). Conclusions The results indicate that morphine lowers the threshold of helium preconditioning. Opioid receptors mediate helium preconditioning and its augmentation by morphine in vivo. PMID:19231239

  3. Ranolazine: effects on ischemic heart.

    PubMed

    Rognoni, Andrea; Barbieri, Lucia; Cavallino, Chiara; Bacchini, Sara; Veia, Alessia; Degiovanni, Anna; Rametta, Francesco; Nardi, Federico; Lazzero, Maurizio; Lupi, Alessandro; Bongo, Angelo S

    2013-12-01

    Coronary artery disease is the major cause of mortality and morbidity in the industrialized countries; in the United States of America and in Europe, it is responsible for one of every six deaths per year. In the setting of ischemic heart disease, angina pectoris and chest pain, in particular, are the major causes of emergency department accesses. Angina pectoris is a clinical syndrome characterized by discomfort typically in the chest, neck, chin and left arm induced by physical exertion, emotional stress and cold and is relieved by rest or by taking of nitrates. The main targets of treatment of angina pectoris are to improve quality of life by reducing the frequency and the severity of symptoms, to increase functional capacity and to improve prognosis. Ranolazine is a recent antianginal drug with unique methods of action. It was approved by the US Food and Drug Administration in 2006 as add-on therapy in patients symptomatic for stable angina. With the inhibition of the late sodium current, Ranolazine protects against ion deregulation, prevents cellular calcium overload and the subsequent increase in diastolic tension without impacting heart rate and blood pressure. Short term clinical trials and patent research show that add on therapy with Ranolazine in patients with chronic stable angina significantly improves exercise duration, exercise time to angina and reduces the use of nitro glycerine. Long term clinical trials showed no significant differences in the rate of cardiovascular death and myocardial infarction in patients with non-ST segment elevation acute coronary syndromes but a reduction in terms of recurrent ischemia. Ranolazine is generally well tolerated and even if it increases the duration of QTc interval it is not associated with atrial and ventricular arrhythmias. Therefore Ranolazine represents a good therapeutic approach in patients with chronic stable angina still symptomatic, while on optimal anti-ischemic therapy, or intolerant to traditional anti-ischemic drugs. PMID:23961914

  4. Chlamydia in Anterior Ischemic Optic Neuropathy

    Microsoft Academic Search

    Pia V. Vécsei; Karl Kircher; Andreas Reitner; Gelas Khanakha; Gerold Stanek

    2002-01-01

    There is an increasing body of evidence linking the common respiratory human pathogen Chlamydia pneumoniae with atherosclerosis and other vascular disorders. Our research was designed to investigate the association of this organism with anterior ischemic optic neuropathy (AION), representing an acute ischemic disorder of the optic nerve head. Sera were examined of 14 consecutive patients with AION and of 14

  5. Vasoconstrictive neurovascular coupling during focal ischemic depolarizations

    Microsoft Academic Search

    Hwa Kyoung Shin; Andrew K Dunn; Phillip B Jones; David A Boas; Michael A Moskowitz; Cenk Ayata

    2006-01-01

    Ischemic depolarizing events, such as repetitive spontaneous periinfarct spreading depolarizations (PIDs), expand the infarct size after experimental middle cerebral artery (MCA) occlusion. This worsening may result from increased metabolic demand, exacerbating the mismatch between cerebral blood flow (CBF) and metabolism. Here, we present data showing that anoxic depolarization (AD) and PIDs caused vasoconstriction and abruptly reduced CBF in the ischemic

  6. Anterior leaflet augmentation for ischemic mitral regurgitation

    Microsoft Academic Search

    Edward H Kincaid; Robert D Riley; Michael H Hines; John W Hammon; Neal D Kon

    2004-01-01

    BackgroundMitral valve repair improves survival and quality of life in patients with ischemic mitral regurgitation (MR). Although many repair methods exist for this condition, the ideal approach remains unknown. The purpose of this study is to describe a simple technique for repair of ischemic MR that addresses the pathophysiology of tethered leaflets and to report its early results.

  7. Preconditioned Krylov subspace methods for solving nonsymmetric matrices from CFD applications

    E-print Network

    Zhang, Jun

    Preconditioned Krylov subspace methods for solving nonsymmetric matrices from CFD applications Jun arising computational dynamics (CFD) applications. preconditioned iterative methods consist of KrylovCGSTAB, GMRES and TFQMR. Numerical experiments, using several matrices arising various relevant CFD applications

  8. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  9. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  10. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 2011-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  11. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  12. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  13. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  14. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 2012-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  15. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  16. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  17. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  18. 40 CFR 92.125 - Pre-test procedures and preconditioning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Pre-test procedures and preconditioning. 92.125 Section...POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.125 Pre-test procedures and preconditioning. (a)...

  19. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 2013-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  20. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  1. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 2010-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  2. LE ROUTAGE IP septembre 2006 1/57Version 2.0 LE ROUTAGE IP

    E-print Network

    Paris-Sud XI, Université de

    LE ROUTAGE IP septembre 2006 1/57Version 2.0 LE ROUTAGE IP Luc.Saccavini@inria.fr septembre 2006 #12;LE ROUTAGE IP septembre 2006 2/57Version 2.0 Eléments sur le protocole IP Chaque «objet IP» est identifié par une/des adresse(s) IP qui contient L'adresse du réseau IP local (extraite grâce au Netmask) Le

  3. Is red blood cell a mediator of remote ischaemic preconditioning?

    PubMed

    Gopalakrishnan, Maya; Saurabh, Suman

    2014-12-01

    Remote ischaemic preconditioning is emerging as a promising clinical technique which can afford immediate protection against coronary ischaemia. The mechanisms which mediate the signal transduction from remote organ to the heart are still unclear. The role of ATP sensitive potassium channels in ischaemic preconditioning has been established. It is known that the red blood cell (RBC) acts as a mediator of local autoregulation in adjusting oxygen supply to demand by sensing hypoxia and releasing ATP locally to achieve vasodilatation in the adjacent vascular beds. Our hypothesis links these two known mechanisms. Remote ischaemic preconditioning and local RBC autoregulation might share a common mechanism using the ATP sensitive potassium channels. Therefore, we hypothesize that the signal transduction by RBC might be partly responsible for this protection against ischaemia. PMID:25468784

  4. Liquid hydrogen turbopump rapid start program. [thermal preconditioning using coatings

    NASA Technical Reports Server (NTRS)

    Wong, G. S.

    1973-01-01

    This program was to analyze, test, and evaluate methods of achieving rapid-start of a liquid hydrogen feed system (inlet duct and turbopump) using a minimum of thermal preconditioning time and propellant. The program was divided into four tasks. Task 1 includes analytical studies of the testing conducted in the other three tasks. Task 2 describes the results from laboratory testing of coating samples and the successful adherence of a KX-635 coating to the internal surfaces of the feed system tested in Task 4. Task 3 presents results of testing an uncoated feed system. Tank pressure was varied to determine the effect of flowrate on preconditioning. The discharge volume and the discharge pressure which initiates opening of the discharge valve were varied to determine the effect on deadhead (no through-flow) start transients. Task 4 describes results of testing a similar, internally coated feed system and illustrates the savings in preconditioning time and propellant resulting from the coatings.

  5. How dynamic are IP addresses?

    Microsoft Academic Search

    Yinglian Xie; Fang Yu; Kannan Achan; Eliot Gillum; Moisés Goldszmidt; Ted Wobber

    2007-01-01

    This paper introduces a novel method, UDmap, to identify dy- namically assigned IP addresses and analyze their dynamics pat- tern. UDmap is fully automatic, and relies only on application-level server logs that are already available today. We applied UDmap to a month-long Hotmail user-login trace and identified a significant number of dynamic IP addresses - more than 102 million. This

  6. Hyperspectral imaging of ischemic wounds

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Elgharably, Haytham; Melvin, James; Huang, Kun; Bergdall, Valerie; Allen, David W.; Hwang, Jeeseong; Litorja, Maritoni; Shirley, Eric; Sen, Chandan K.; Xu, Ronald

    2012-03-01

    Optical imaging has the potential to achieve high spatial resolution and high functional sensitivity in wound assessment. However, clinical acceptance of many optical imaging devices is hampered by poor reproducibility, low accuracy, and lack of biological interpretation. We developed an in vivo model of ischemic flap for non-contact assessment of wound tissue functional parameters and spectral characteristics. The model was created by elevating the bipedicle skin flaps of a domestic pig from the underlying vascular bed and inhibiting graft bed reperfusion by a silastic sheet. Hyperspectral imaging was carried out on the ischemic flap model and compared with transcutaneous oxygen tension and perfusion measurements at different positions of the wound. Hyperspectral images have also been captured continuously during a post-occlusive reactive hyperemia (PORH) procedure. Tissue spectral characteristics obtained by hyperspectral imaging correlated well with cutaneous tissue oxygen tension, blood perfusion, and microscopic changes of tissue morphology. Our experiments not only demonstrated the technical feasibility for quantitative assessment of chronic wound but also provided a potential digital phantom platform for quantitative characterization and calibration of medical optical devices.

  7. Collaborative scheme for VoIP traceback

    Microsoft Academic Search

    Hsien-Ming Hsu; Yeali S. Sun; Meng Chang Chen

    2011-01-01

    While voice over IP (VoIP) services have brought many desirable communication features to the general public, they have also become a medium through which criminals communicate and conduct illegal activities e.g., fraud and blackmail without being intercepted by law enforcement agencies (LEAs). Previous research on IP traceback focused on tracking IP addresses on the network layer. The mechanisms developed thus

  8. Voix sur IP Julien Vey Gil Noirot

    E-print Network

    Perronnin, Florence

    Voix sur IP Julien Vey Gil Noirot Étude d'approfondissement Réseaux #12;Ce dont nous allons parler L'architecture VoIP Les protocoles Les limites de la VoIP Ce dont nous n'allons pas parler Le fonctionnement détaillé du RTC Le traitement du signal JulienVey - Gil Noirot 2VoIP Introduction #12;Introduction

  9. IP Based Design 2002 Session: 3A

    E-print Network

    Ould Ahmedou, Mohameden

    IP Based Design 2002 Session: 3A IP Design for Dynamically Reconfigurable SoCs Tobias Oppold ideas on how to take advantage of reconfiguration and how to automate the design of IP that is running and energy consumption of a standard IP Based SoC Design 2002 - October 30-31, 2002 #12;Spatial Mapping Hard

  10. IP routing issues in satellite constellation networks

    Microsoft Academic Search

    L. Wood; A. Clerget; I. Andrikopoulos; G. Pavlou; W. Dabbous

    2001-01-01

    SUMMARY The growth in use of Internet-based applications in recent years has led to telecommunication networks transporting an increasingly large amount of Internet Protocol (IP)-based traffic. Proposed broadband satellite constellation networks, currently under development, will be required to transport IP traffic. A case can be made for implementing IP routing directly within the constellation network, in order to transport IP

  11. Thermal Preconditioning and Heat-Shock Protein 72 Preserve Synaptic Transmission during Thermal Stress

    E-print Network

    Robertson, Meldrum

    Thermal Preconditioning and Heat-Shock Protein 72 Preserve Synaptic Transmission during Thermal, exposing the mammalian CNS to nonle- thal heat stress (i.e., thermal preconditioning) increases levels that generates respiratory rhythm (the pre- Bo¨ tzinger complex), we show that thermal preconditioning has

  12. Recent Progress in Parallel Schur Complement Preconditioning for Computational Fluid

    NASA Technical Reports Server (NTRS)

    Barth, Tim; Kwak, Dochan (Technical Monitor)

    1997-01-01

    We consider preconditioning methods for nonself-adjoint advective-diffusive systems based on a nonoverlapping Schur complement procedure for arbitrary triangulated domains. The triangulation is first partitioned using the METIS multi-level $k$-way partitioning code. This partitioning of the triangulation induces a natural 2x2 partitioning of the demoralization matrix. By considering various inverse approximations of the 2x2 system we have developed a family of robust preconditioning techniques. The performance of these approximations will be discussed and numerous examples shown to illustrate the efficiency of the technique.

  13. Choice of Variables and Preconditioning for Time Dependent Problems

    NASA Technical Reports Server (NTRS)

    Turkel, Eli; Vatsa, Verr N.

    2003-01-01

    We consider the use of low speed preconditioning for time dependent problems. These are solved using a dual time step approach. We consider the effect of this dual time step on the parameter of the low speed preconditioning. In addition, we compare the use of two sets of variables, conservation and primitive variables, to solve the system. We show the effect of these choices on both the convergence to a steady state and the accuracy of the numerical solutions for low Mach number steady state and time dependent flows.

  14. Traditional IP Measurements: What Changes in a Today Multimedia IP Network

    E-print Network

    Traditional IP Measurements: What Changes in a Today Multimedia IP Network Delia Ciullo, Marco IP architecture and delivers to the user data, VoIP and IPTV services over a single broadband characteristics of data traffic are kept unmodified, showing LRD properties both at the packet and flow levels. VoIP

  15. IP over ATM: Classical IP, NHRP, LANE, MPOA, PAR and I-PNNI

    E-print Network

    Jain, Raj

    IP over ATM: Classical IP, NHRP, LANE, MPOA, PAR and I-PNNI Jun Xu Due to the popularity and dominance of the TCP/IP, the success of ATM as a data networking technology lies largely in its support of IP on top of it. This report surveys the proposed approaches of transporing IP traffic

  16. Empirical tests of anonymous voice over IP

    Microsoft Academic Search

    Marc Liberatore; Bikas Gurung; Brian Neil Levine; Matthew K. Wright

    2011-01-01

    Voice over IP (VoIP) is an important service on the Internet, and privacy for VoIP calls will be increasingly important for many people. Providing this privacy, however, is challenging, as anonymity services can be slow and unpredictable. In this paper, we propose a method for extending onion-routing style anonymity protocols for supporting anonymous VoIP (aVoIP) traffic with reasonable performance. We

  17. Performance of VoIP on HSDPA

    Microsoft Academic Search

    Bang Wang; Klaus I. Pedersen; Troels E. Kolding; Preben E. Mogensen

    2005-01-01

    This paper provides packet scheduler design and performance simulations for running VoIP services over high-speed downlink packet access (HSDPA) in WCDMA. The main challenge of supporting VoIP service on HSDPA is the tight delay requirement combined with the small VoIP packet size. A packet scheduler design incorporating VoIP packet aggregation and user multiplexing is proposed and the VoIP capacity is

  18. Ischemic post-conditioning to counteract intestinal ischemia/reperfusion injury.

    PubMed

    Guan, Yan-Fang; Pritts, Timothy A; Montrose, Marshall H

    2010-10-15

    Intestinal ischemia is a severe disorder with a variety of causes. Reperfusion is a common occurrence during treatment of acute intestinal ischemia but the injury resulting from ischemia/reperfusion (IR) may lead to even more serious complications from intestinal atrophy to multiple organ failure and death. The susceptibility of the intestine to IR-induced injury (IRI) appears from various experimental studies and clinical settings such as cardiac and major vascular surgery and organ transplantation. Whereas oxygen free radicals, activation of leukocytes, failure of microvascular perfusion, cellular acidosis and disturbance of intracellular homeostasis have been implicated as important factors in the pathogenesis of intestinal IRI, the mechanisms underlying this disorder are not well known. To date, increasing attention is being paid in animal studies to potential pre- and post-ischemia treatments that protect against intestinal IRI such as drug interference with IR-induced apoptosis and inflammation processes and ischemic pre-conditioning. However, better insight is needed into the molecular and cellular events associated with reperfusion-induced damage to develop effective clinical protection protocols to combat this disorder. In this respect, the use of ischemic post-conditioning in combination with experimentally prolonged acidosis blocking deleterious reperfusion actions may turn out to have particular clinical relevance. PMID:21607154

  19. Growth factors in ischemic stroke

    PubMed Central

    Lanfranconi, S; Locatelli, F; Corti, S; Candelise, L; Comi, G P; Baron, P L; Strazzer, S; Bresolin, N; Bersano, A

    2011-01-01

    Abstract Data from pre-clinical and clinical studies provide evidence that colony-stimulating factors (CSFs) and other growth factors (GFs) can improve stroke outcome by reducing stroke damage through their anti-apoptotic and anti-inflammatory effects, and by promoting angiogenesis and neurogenesis. This review provides a critical and up-to-date literature review on CSF use in stroke. We searched for experimental and clinical studies on haemopoietic GFs such as granulocyte CSF, erythropoietin, granulocyte-macrophage colony-stimulating factor, stem cell factor (SCF), vascular endothelial GF, stromal cell-derived factor-1? and SCF in ischemic stroke. We also considered studies on insulin-like growth factor-1 and neurotrophins. Despite promising results from animal models, the lack of data in human beings hampers efficacy assessments of GFs on stroke outcome. We provide a comprehensive and critical view of the present knowledge about GFs and stroke, and an overview of ongoing and future prospects. PMID:20015202

  20. Endovascular Therapy for Ischemic Stroke

    PubMed Central

    Appireddy, Ramana M R; Demchuk, Andrew M; Goyal, Mayank; Menon, Bijoy K; Eesa, Muneer; Choi, Philip

    2015-01-01

    The utility of intravenous tissue plasminogen activator (IV t-PA) in improving the clinical outcomes after acute ischemic stroke has been well demonstrated in past clinical trials. Though multiple initial small series of endovascular stroke therapy had shown good outcomes as compared to IV t-PA, a similar beneficial effect had not been translated in multiple randomized clinical trials of endovascular stroke therapy. Over the same time, there have been parallel advances in imaging technology and better understanding and utility of the imaging in therapy of acute stroke. In this review, we will discuss the evolution of endovascular stroke therapy followed by a discussion of the key factors that have to be considered during endovascular stroke therapy and directions for future endovascular stroke trials. PMID:25628731

  1. 40 CFR 86.1232-96 - Vehicle preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...1) Gasoline- and methanol-fueled vehicles...preconditioned separately. If production evaporative canisters...per hour. (2) For methanol-fueled and flexible-fueled...prior to loading. If production evaporative canisters...of hydrocarbons, of methanol, or of methanol...

  2. 40 CFR 86.132-96 - Vehicle preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...1) Gasoline- and methanol-fueled vehicles...preconditioned separately. If production evaporative canisters...per hour. (2) For methanol-fueled and flexible-fueled...prior to loading. If production evaporative canisters...of hydrocarbons, of methanol, or of methanol...

  3. 40 CFR 86.1232-96 - Vehicle preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...1) Gasoline- and methanol-fueled vehicles...preconditioned separately. If production evaporative canisters...per hour. (2) For methanol-fueled and flexible-fueled...prior to loading. If production evaporative canisters...of hydrocarbons, of methanol, or of methanol...

  4. 40 CFR 86.132-96 - Vehicle preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...1) Gasoline- and methanol-fueled vehicles...preconditioned separately. If production evaporative canisters...per hour. (2) For methanol-fueled and flexible-fueled...prior to loading. If production evaporative canisters...of hydrocarbons, of methanol, or of methanol...

  5. Planar amperometric oxygen sensor with improved preconditioning property

    Microsoft Academic Search

    Sung Hyuk Choi; Jeonghan Ha; Jae Ho Shin; Yong Suk Choi; Sang Hyun Han; Hakhyun Nam; Geun Sig Cha

    2001-01-01

    The feasibility of enhancing the preconditioning time property of the planar type amperometric oxygen sensor is investigated. A gas permeable membrane is formulated by incorporating hydrophilic polyurethane (HPU) into a one-component room temperature vulcanizing (RTV) silicone rubber matrix. Planar oxygen sensors are made by forming a recipient hydrogel layer on the base electrodes screen printed on a substrate, and by

  6. Dexmedetomidine Preconditioning Attenuates Cisplatin-Induced Ototoxicity in Zebrafish

    PubMed Central

    Min, Too Jae; Ha, Young Ran; Jeong, In young; Yoo, Ji young

    2014-01-01

    Objectives Utilisation of high-frequency drills is known to increase noise induced hearing loss due to increasing the damages of inner ear cells. This study aimed to investigate whether preconditioning by using dexmedetomidine (DEX) decreased the occurrence of ischemia in inner cells of the ear. Methods We utilised a transgenic zebrafish line Brn3C, and the embryos were collected from breeding adult zebrafish. Five-day-old larvae were cultured at the density of 50 embryos, and the larvae were classified into 4 groups: control, cisplatin group, DEX group, and DEX+yohimbine; adrenoreceptor blocker group. The DEX group was categorised into 3 subgroups by dosage; 0.1, 1, and 10 µM. Preconditioning was performed for 150 minutes and then exposed to cisplatin for 6 hours. The experiment was performed in 7 replicates for each group and the number of hair cells in 3 parts of the neuromasts of each fish was determined. Results Hair cell apoptosis by cisplatin was attenuated more significantly in the DEX preconditioning group than in the control group. However, the preconditioning effects were not blocked by yohimbine. Conclusion The results of this study suggest that hearing loss caused by vibration-induced noise could be reduced by using DEX and may occur through other mechanisms rather than adreno-receptors. PMID:25436046

  7. Minimal preconditioning effects observed for inflation tests of planar tissues.

    PubMed

    Tonge, Theresa K; Murienne, Barbara J; Coudrillier, Baptiste; Alexander, Stephen; Rothkopf, William; Nguyen, Thao D

    2013-11-01

    The purpose of this study is to investigate the effects of preconditioning on the deformation response of planar tissues measured by inflation tests. The inflation response of test specimens, including the bovine cornea, bovine and porcine sclera, and human skin, exhibited a negligible evolving deformation response when subjected to repeated pressure loading with recovery periods between cycles. Tissues obtained complete recovery to the reference state, and strain contours across the entire specimen were nearly identical at the maximum pressure of each load cycle. This repeatability was obtained regardless of strain history. These results suggest that negligible permanent change was induced in the microstructure by inflation testing. Additionally, we present data illustrating that a lack of a recovery period can result in an evolving deformation response to repeated loading that is commonly attributed to preconditioning. These results suggest that the commonly observed effects of preconditioning may be avoided by experimental design for planar tissues characterized by long collagen fibers arranged in the plane of the tissue. Specifically, if the test is designed to fully fix the specimen boundary during loading, adequate recovery periods are allowed after each load cycle, and loads are limited to avoid damage, preconditioning effects may be avoided for planar tissues. PMID:23897279

  8. Efficient Preconditioning of Laplacian Matrices for Computer Graphics Dilip Krishnan

    E-print Network

    Bernstein, Phil

    . It can therefore be used for a wide variety of computational photography problems, as well as several 3D; Keywords: matrix preconditioning, Laplacians, multigrid, mesh processing, computational photography Links Introduction A large number of problems in computer graphics and compu- tational photography are formulated

  9. Preconditioning of PWR steam generators to reduce radiation buildup

    SciTech Connect

    Beslu, P.; Masse, F.; Anthoni, S.; Galliano, N. (CEA Centre d'Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France))

    1992-08-01

    The purpose of the tests carried out on the CORELE loop was to determine whether preconditioning of steam generator tube surfaces could minimize the release rate of corrosion products. The test program and evaluation of the results obtained are included in this report.

  10. Cardiac Workup of Ischemic Stroke

    PubMed Central

    Ustrell, Xavier; Pellisé, Anna

    2010-01-01

    Stroke is the leading cause of disability in developed countries and the third cause of mortality. Up to 15-30% of ischemic strokes are caused by cardiac sources of emboli being associated with poor prognosis and high index of fatal recurrence. In order to establish an adequate preventive strategy it is crucial to identify the cause of the embolism. After a complete diagnostic workup up to 30% of strokes remain with an undetermined cause, and most of them are attributed to an embolic mechanism suggesting a cardiac origin. There is no consensus in the extent and optimal approach of cardiac workup of ischemic stroke. Clinical features along with brain imaging and the study of the cerebral vessels with ultrasonography or MRI/CT based angiography can identify other causes or lead to think about a possible cardioembolic origin. Atrial fibrillation is the most common cause of cardioembolic stroke. Identification of occult atrial fibrillation is essential. Baseline ECG, serial ECG(’s), cardiac monitoring during the first 48 hours, and Holter monitoring have detection rates varying from 4 to 8% each separately. Extended cardiac monitoring with event loop recorders has shown higher rates of detection of paroxysmal atrial fibrillation. Cardiac imaging with echocardiography is necessary to identify structural sources of emboli. There is insufficient data to determine which is the optimal approach. Transthoracic echocardiography has an acceptable diagnostic yield in patients with heart disease but transesophageal echocardiography has a higher diagnostic yield and is necessary if no cardiac sources have been identified in patients with cryptogenic stroke with embolic mechanism. PMID:21804776

  11. Neuroprotective Mechanisms of Taurine against Ischemic Stroke

    PubMed Central

    Menzie, Janet; Prentice, Howard; Wu, Jang-Yen

    2013-01-01

    Ischemic stroke exhibits a multiplicity of pathophysiological mechanisms. To address the diverse pathophysiological mechanisms observed in ischemic stroke investigators seek to find therapeutic strategies that are multifaceted in their action by either investigating multipotential compounds or by using a combination of compounds. Taurine, an endogenous amino acid, exhibits a plethora of physiological functions. It exhibits antioxidative properties, stabilizes membrane, functions as an osmoregulator, modulates ionic movements, reduces the level of pro-inflammators, regulates intracellular calcium concentration; all of which contributes to its neuroprotective effect. Data are accumulating that show the neuroprotective mechanisms of taurine against stroke pathophysiology. In this review, we describe the neuroprotective mechanisms employed by taurine against ischemic stroke and its use in clinical trial for ischemic stroke. PMID:24961429

  12. Cardiac Complications in Acute Ischemic Stroke

    E-print Network

    2011-01-01

    of cardiac function and complications with AIS. EmergencyAIS patients. 50,51 Regarding structural systolic functionAIS (ie, the ischemic penumbra) intrinsic autoregulation of the vasculature is lost, rendering cerebral blood ?ow directly dependent on cardiac function.

  13. Mobility management in mobile IP

    NASA Astrophysics Data System (ADS)

    Medidi, Sirisha; Golshani, Forouzan

    2002-07-01

    There is an emerging interest in integrating mobile wireless communication with the Internet based on the Ipv6 technology. Many issues introduced by the mobility of users arise when such an integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current IP addresses of mobile terminals and sustaining active IP connections as mobiles move. The paper presents some architectural and mobility management options for integrating wireless access to the Internet. We then present performance results for Mobile IPv4, route optimization and Mobile IPv6.

  14. Diagnosis and Management of Ischemic Stroke

    Microsoft Academic Search

    Aslam M. Khaja

    \\u000a Until relatively recently, ischemic stroke management was a classic example of “diagnose and adios.” Care of patients presenting\\u000a to the hospital or clinic with symptoms of stroke consisted of aspirin followed by rehabilitation, with few disease-specific\\u000a strategies directed toward optimal treatment and outcomes. The past two decades have witnessed an explosion of research into\\u000a ischemic stroke. We now have specific

  15. An adenosine agonist and preconditioning shift the distribution of myocardial blood flow in conscious pigs.

    PubMed

    Huang, C H; Kim, S J; Ghaleh, B; Kudej, R K; Shen, Y T; Bishop, S P; Vatner, S F

    1999-02-01

    The goal of this study was to determine whether the cardioprotective effects of an A1-receptor agonist and ischemic preconditioning (IPC) involve a shift in the pre-coronary artery occlusion (CAO) spatial distribution of myocardial blood flow, which might shed light on the mechanism of IPC and explain its heterogeneous effects. Accordingly, 60 min of CAO followed by 72 h of coronary artery reperfusion (CAR) was examined in three groups of conscious pigs 10-14 days after instrumentation with aortic and left atrial catheters and coronary artery occluders. Myocardial infarct size, expressed as a fraction of the area at risk (AAR), was reduced significantly (P < 0.05) by infusion of the A1 agonist (27.1 +/- 6.6%) and to a greater extent (P < 0.05) by IPC (11.6 +/- 5.1%) compared with infarct size in vehicle-treated animals (55.1 +/- 2.9%). Transmural myocardial blood flow (radioactive microspheres) in the AAR shifted toward lower levels after infusion of the A1 agonist (1.27 +/- 0.19 vs. 0.74 +/- 0.10 ml. min-1. g-1) or IPC (1.27 +/- 0.11 vs. 0.96 +/- 0.09 ml. min-1. g-1) but not after infusion of the vehicle (1.20 +/- 0.10 vs. 1.23 +/- 0.09 ml. min-1. g-1). This study demonstrated that both pretreatment with an adenosine A1 agonist and also IPC altered the spatial distribution of pre-CAO myocardial blood flow, which might reflect a downregulation of metabolic state and thus play a role in the cardioprotective effects of IPC. PMID:9950835

  16. Project no. 004089 Instrument : IP

    E-print Network

    Guichard, Francoise

    Project no. 004089 AMMA Instrument : IP D.2.1.A.e The impacts of contrasting atmospheric date: December 2009 Start date of project: 1st January of 2005 Duration: 60 months Organisation name of lead contractor for this deliverable: CNRM Prepared by F. Guichard (CNRM) Project co

  17. IP Address Passing for VANETs

    Microsoft Academic Search

    Todd Arnold; Wyatt Lloyd; Jing Zhao; Guohong Cao

    2008-01-01

    In Vehicular Ad-hoc Networks (VANETs), vehicles can gain short connections to the Internet by using wireless ac- cess points (AP). A significant part of the connection time is the time required for acquiring an IP address via Dynamic Host Configuration Protocol (DHCP). Depending on a ve- hicle's speed and the AP coverage area, DHCP can con- sume up to 100

  18. Continuously Connected With Mobile IP

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Cisco Systems developed Cisco Mobile Networks, making IP devices mobile. With this innovation, a Cisco router and its connected IP devices can roam across network boundaries and connection types. Because a mobile user is able to keep the same IP address while roaming, a live IP connection can be maintained without interruption. Glenn Research Center jointly tested the technology with Cisco, and is working to use it on low-earth-orbiting research craft. With Cisco's Mobile Networks functionality now available in Cisco IOS Software release 12.2(4)T, the commercial advantages and benefits are numerous. The technology can be applied to public safety, military/homeland security, emergency management services, railroad and shipping systems, and the automotive industry. It will allow ambulances, police, firemen, and the U.S. Coast Guard to stay connected to their networks while on the move. In the wireless battlefield, the technology will provide rapid infrastructure deployment for U.S. national defense. Airline, train, and cruise passengers utilizing Cisco Mobile Networks can fly all around the world with a continuous Internet connection. Cisco IOS(R) Software is a registered trademark of Cisco Systems.

  19. Strategies for Study of Neuroprotection from Cold-preconditioning

    PubMed Central

    Mitchell, Heidi M.; White, David M.; Kraig, Richard P.

    2010-01-01

    Neurological injury is a frequent cause of morbidity and mortality from general anesthesia and related surgical procedures that could be alleviated by development of effective, easy to administer and safe preconditioning treatments. We seek to define the neural immune signaling responsible for cold-preconditioning as means to identify novel targets for therapeutics development to protect brain before injury onset. Low-level pro-inflammatory mediator signaling changes over time are essential for cold-preconditioning neuroprotection. This signaling is consistent with the basic tenets of physiological conditioning hormesis, which require that irritative stimuli reach a threshold magnitude with sufficient time for adaptation to the stimuli for protection to become evident. Accordingly, delineation of the immune signaling involved in cold-preconditioning neuroprotection requires that biological systems and experimental manipulations plus technical capacities are highly reproducible and sensitive. Our approach is to use hippocampal slice cultures as an in vitro model that closely reflects their in vivo counterparts with multi-synaptic neural networks influenced by mature and quiescent macroglia / microglia. This glial state is particularly important for microglia since they are the principal source of cytokines, which are operative in the femtomolar range. Also, slice cultures can be maintained in vitro for several weeks, which is sufficient time to evoke activating stimuli and assess adaptive responses. Finally, environmental conditions can be accurately controlled using slice cultures so that cytokine signaling of cold-preconditioning can be measured, mimicked, and modulated to dissect the critical node aspects. Cytokine signaling system analyses require the use of sensitive and reproducible multiplexed techniques. We use quantitative PCR for TNF-? to screen for microglial activation followed by quantitative real-time qPCR array screening to assess tissue-wide cytokine changes. The latter is a most sensitive and reproducible means to measure multiple cytokine system signaling changes simultaneously. Significant changes are confirmed with targeted qPCR and then protein detection. We probe for tissue-based cytokine protein changes using multiplexed microsphere flow cytometric assays using Luminex technology. Cell-specific cytokine production is determined with double-label immunohistochemistry. Taken together, this brain tissue preparation and style of use, coupled to the suggested investigative strategies, may be an optimal approach for identifying potential targets for the development of novel therapeutics that could mimic the advantages of cold-preconditioning. PMID:20834222

  20. Chemical preconditioning-induced reactive astrocytosis contributes to the reduction of post-ischemic edema through aquaporin-4 downregulation

    Microsoft Academic Search

    Akihiko Hoshi; Teiji Yamamoto; Keiko Shimizu; Yoshihiro Sugiura; Yoshikazu Ugawa

    2011-01-01

    Aquaporins are a family of membrane proteins that promote the transmembrane diffusion of water. Aquaporin-4 (AQP4) is a predominant water channel protein in the brain and is concentrated in the end-feet of astrocytes. A critical question is what role astrocytic AQP4 plays in pathological conditions. Another matter to be elucidated is the relationship between morphological changes in astrocytes and AQP4

  1. Mitochondrial ROS production and subsequent ERK phosphorylation are necessary for temperature preconditioning of isolated ventricular myocytes

    PubMed Central

    Bhagatte, Y; Lodwick, D; Storey, N

    2012-01-01

    Hypothermia and hypothermic preconditioning are known to be profoundly cardioprotective, but the molecular mechanisms of this protection have not been fully explained. In this study, temperature preconditioning (16?°C) was found to be cardioprotective in isolated adult rat ventricular myocytes, enhancing contractile recovery and preventing calcium dysregulation after oxidative stress. Hypothermic preconditioning preserved mitochondrial function by delaying the pathological opening of the mitochondrial permeability transition pore (mPTP), whereas transient mPTP flickering remained unaltered. For the first time, reactive oxygen species (ROS) from the mitochondria are shown to be released exclusively during the hypothermic episodes of the temperature-preconditioning protocol. Using a mitochondrially targeted ROS biosensor, ROS release was shown during the brief bursts to 16?°C of temperature preconditioning. The ROS scavenger N-(2-mercaptopropionyl) glycine attenuated ROS accumulation during temperature preconditioning, abolishing the protective delay in mPTP opening. Temperature preconditioning induces ROS-dependant phosphorylation of the prosurvival kinase extracellular signal-regulated kinase (ERK)1/2. ERK1/2 activation was shown to be downstream of ROS release, as the presence of a ROS scavenger during temperature preconditioning completely blocked ERK1/2 activation. The cardioprotective effects of temperature preconditioning on mPTP opening were completely lost by inhibiting ERK1/2 activation. Thus, mitochondrial ROS release and ERK1/2 activation are both necessary to signal the cardioprotective effects of temperature preconditioning in cardiac myocytes. PMID:22764104

  2. Towards more power efficient IP lookup engines 

    E-print Network

    Ahmad, Seraj

    2007-04-25

    , which limits the throughput considerably. On the other hand, IP lookup throughput requirements have been continuously increasing. This has led to ternary content addressable memory(TCAM) based IP lookup engines which can perform a single lookup every...

  3. VoIP in a Campus Environment

    ERIC Educational Resources Information Center

    Young, Dan

    2005-01-01

    Internet Protocol (IP) Telephony, or voice-over IP (VoIP), has proved to be a wise decision for many organizations. This technology crosses the boundaries of public and private networks, enterprise and residential markets, voice and data technologies, as well as local and long-distance services. The convergence of voice and data into a single,…

  4. Resolved problems Wider IP resolution for rawhits

    E-print Network

    to a integer ­ Fixed by Alberto Strong IP asymmetry ­ Clustering mismatch between ftksim and banks ­ NowResolved problems Wider IP resolution for rawhits ­ Clustering: rounding cluster center follow... #12;Clustering vs IP width (corrgen) :-) #12;At high Pt, rawhit performance approaches

  5. Section Notes 8 IP: Cutting Planes

    E-print Network

    Chen, Yiling

    formulations P1 and P2 for the same integer programming (IP) problem, where Pi denotes the formulation of the feasible integer solutions the best formulation for an IP we can hope for? 3. Why do we think we can solveSection Notes 8 IP: Cutting Planes Applied Math / Engineering Sciences 121 Week of November 3, 2014

  6. Section Notes 9 IP: Cutting Planes

    E-print Network

    Chen, Yiling

    for the same integer programming (IP) problem, where Pi denotes the formulation for a problem prefer stronger formulations for IPs over weaker ones? 2. Why is the convex hull of the feasible integerSection Notes 9 IP: Cutting Planes Applied Math 121 Week of April 12, 2010 Goals for the week

  7. PSAT: Proactive Signaling Architecture for IP Traceback

    Microsoft Academic Search

    Ahmad Fadlallah; Ahmed Serhrouchni

    2006-01-01

    As the Internet becomes pervasive, the vulnerability of some fundamental design aspects of the Internet has also become relevant. The rising threat of cyber attacks makes the IP traceback problem very relevant to today's Internet security. Unfortunately, there is no easy way to track IP traffic to its source due to the stateless nature of the IP protocol, and to

  8. Understanding IP Prefix Hijacking and its Detection

    Microsoft Academic Search

    Christian Horn

    Since IP Prefix Hijacking is a major threat for every Autonomous System in the Internet, this paper tries to give an understanding of IP prefix hijacking and some of their detection methods. This may rise attention and awareness for that topic among the readers. If a malicious attacker would hijack an IP and use it for committing serious crimes, the

  9. IP RELEASE TIMELINES (i) If federally funded

    E-print Network

    Ober, Carole

    IP RELEASE TIMELINES (i) If federally funded (ii) If patent filings already associated) Patent Firm & Inventor Designee Form IP Assignment Agreement to Inventors (iii) Inventor(s) return NIH Inventor Certification Form (i) Patent Firm & Inventor Designee Form IP Assignment Agreement to Inventors

  10. Faster IP Lookups Using Controlled Prefix Expansion

    Microsoft Academic Search

    Venkatachary Srinivasan; George Varghese

    1998-01-01

    Internet (IP) address lookup is a major bottleneck in high performance routers. IP address lookup is challenging because it requires . Controlled prefix expansion, together with optimization techniques based on dynamic programming, can be used to improve the speed of the best known IP lookup algorithms by at least a factor of two. When applied to trie search, our techniques

  11. RESEARCH & INNOVATION OFFICE EASY ACCESS IP

    E-print Network

    University of Technology, Sydney

    RESEARCH & INNOVATION OFFICE EASY ACCESS IP AN INTRODUCTION FOR UTS RESEARCHERS FEBRUARY 2014 #12;AN INTRODUCTION TO EASY ACCESS IP FOR UTS RESEARCHERS ­ FEBRUARY 2014 Background Easy Access of Bristol to promote new ways of sharing intellectual property (IP) and adopt new approaches to make

  12. RESEARCH & INNOVATION OFFICE EASY ACCESS IP

    E-print Network

    University of Technology, Sydney

    RESEARCH & INNOVATION OFFICE EASY ACCESS IP AN INTRODUCTION FOR INDUSTRY PARTNERS FEBRUARY 2014 #12;AN INTRODUCTION TO EASY ACCESS IP FOR INDUSTRY PARTNERS ­ FEBRUARY 2014 INTRODUCTION TO EASY ACCESS IP AT UTS UTS is dedicated to the discovery and dissemination of knowledge and to delivering impact

  13. Cisco IP 7935/7936 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    Cisco IP 7935/7936 FONCTIONS T�L�PHONIQUES Légende des touches de fonctions 1 Modèle de l surbrillance dans le menu. 6 Touches interactives Permet de sélectionner les touches interactives. #12;Cisco IP la sonnerie et le contraste. #12;Cisco IP 7935/7936 FONCTIONS T�L�PHONIQUES Légende des touches

  14. Logging based IP Traceback in switched ethernets

    Microsoft Academic Search

    Marios S. Andreou; Aad P. A. van Moorsel

    2008-01-01

    IP Traceback systems facilitate tracing of IP packets back to their origin, despite possibly forged or overwritten source address data. A common shortcoming of existing proposals is that they identify source network, but not the source host. Our work extends the traceback process to allow tracing of (switched) Ethernet frames. We build on SPIE (which oper- ates at IP routers)

  15. Observed structure of addresses in IP traffic

    Microsoft Academic Search

    Eddie Kohler; Jinyang Li; Vern Paxson; Scott Shenker

    2002-01-01

    This paper investigates the structure of addresses contained in IP traffic. Specifically, we analyze the structural characteristics of destination IP addresses seen on Interuet links, considered as a subset of the address space. These characteristics may have implications for algorithms that deal with IP address aggregates, such as routing lookups and aggregatebased congestion control. We find that address structures are

  16. Approaches for resolving dynamic IP addressing

    Microsoft Academic Search

    Schubert Foo; Siu Cheung Hui; See Wai Yip; Yulan He

    1997-01-01

    Knowledge of the Internet Protocol (IP) address is essential for connection establishment in certain classes of synchronous distributed applications, such as Internet telephony and video-conferencing systems. A problem of dynamic IP addressing arises when the connection to the Internet is through an Internet service provider, since the IP address is dynamically allocated only at connection time. Proposes and draws a

  17. Network Terminology TCP/IP Network Layers

    E-print Network

    Ramkumar, Mahalingam

    Network Terminology TCP/IP Network Layers Socket Programming Data Communication and Computer;Network Terminology TCP/IP Network Layers Socket Programming 1 Network Terminology 2 TCP/IP Network Layers Programming Data Communication Networks Data (digital data - chunks of bits) Communication (exchange of data

  18. Raj JainThe Ohio State University TCP/IP ProtocolTCP/IP Protocol

    E-print Network

    Jain, Raj

    Raj JainThe Ohio State University 1 TCP/IP ProtocolTCP/IP Protocol Suite and Internetworking terms and services Internet Protocol (IP): Services, Header, Address format #12;Raj JainThe Ohio State University 3 Key Differences From OSIKey Differences From OSI Connectionless Service: TCP/IP

  19. ENABLING PARTIALLY RECONFIGURABLE IP CORES PARAMETERISATION AND INTEGRATION USING MARTE AND IP-XACT

    E-print Network

    Paris-Sud XI, Université de

    ENABLING PARTIALLY RECONFIGURABLE IP CORES PARAMETERISATION AND INTEGRATION USING MARTE AND IP facilitates the parameterization and integration of IP cores into partially reconfigurable SoC platforms) methodology, which exploits two widely used standards for Systems-on-Chip specification, MARTE and IP

  20. Preconditioned iterative methods for Navier-Stokes control problems

    NASA Astrophysics Data System (ADS)

    Pearson, John W.

    2015-07-01

    PDE-constrained optimization problems are a class of problems which have attracted much recent attention in scientific computing and applied science. In this paper we discuss preconditioned iterative methods for a class of (time-independent) Navier-Stokes control problems, one of the main problems of this type in the field of fluid dynamics. Having detailed the Picard-type iteration we use to solve the problems and derived the structure of the matrix system to be solved at each step, we utilize the theory of saddle point systems to develop efficient preconditioned iterative solution techniques for these problems. We also require theory of solving convection-diffusion control problems, as well as a commutator argument to justify one of the components of the preconditioner.

  1. Preconditioning effects of intermittent stream flow on leaf litter decomposition

    Microsoft Academic Search

    D. Dieter; D. von Schiller; E. M. García-Roger; M. M. Sánchez-Montoya; R. Gómez; J. Mora-Gómez; F. Sangiorgio; J. Gelbrecht; K. Tockner

    Autumnal input of leaf litter is a pivotal energy source in most headwater streams. In temporary streams, however, water stress\\u000a may lead to a seasonal shift in leaf abscission. Leaves accumulate at the surface of the dry streambed or in residual pools\\u000a and are subject to physicochemical preconditioning before decomposition starts after flow recovery. In this study, we experimentally\\u000a tested

  2. Preconditioning the bidomain model with almost linear complexity

    NASA Astrophysics Data System (ADS)

    Pierre, Charles

    2012-01-01

    The bidomain model is widely used in electro-cardiology to simulate spreading of excitation in the myocardium and electrocardiograms. It consists of a system of two parabolic reaction diffusion equations coupled with an ODE system. Its discretisation displays an ill-conditioned system matrix to be inverted at each time step: simulations based on the bidomain model therefore are associated with high computational costs. In this paper we propose a preconditioning for the bidomain model either for an isolated heart or in an extended framework including a coupling with the surrounding tissues (the torso). The preconditioning is based on a formulation of the discrete problem that is shown to be symmetric positive semi-definite. A block LU decomposition of the system together with a heuristic approximation (referred to as the monodomain approximation) are the key ingredients for the preconditioning definition. Numerical results are provided for two test cases: a 2D test case on a realistic slice of the thorax based on a segmented heart medical image geometry, a 3D test case involving a small cubic slab of tissue with orthotropic anisotropy. The analysis of the resulting computational cost (both in terms of CPU time and of iteration number) shows an almost linear complexity with the problem size, i.e. of type nlog ?( n) (for some constant ?) which is optimal complexity for such problems.

  3. Candesartan and glycyrrhizin ameliorate ischemic brain damage through downregulation of the TLR signaling cascade.

    PubMed

    Barakat, Waleed; Safwet, Nancy; El-Maraghy, Nabila N; Zakaria, Mohamed N M

    2014-02-01

    Stroke is the second leading cause of death in industrialized countries and the most frequent cause of permanent disability in adults worldwide. The final outcome of stroke is determined not only by the volume of the ischemic core, but also by the extent of secondary brain damage inflicted to penumbral tissues by brain swelling, impaired microcirculation, and inflammation. The only drug approved for the treatment ischemic stroke is recombinant tissue plasminogen activator (rt-PA). The current study was designed to investigate the protective effects of candesartan (0.15 mg/kg, orally) and glycyrrhizin (30 mg/kg, orally) experimentally-induced ischemic brain damage in C57BL/6 mice (middle cerebral artery occlusion, MCAO) in comparison to the effects of a standard neuroprotective drug (cerebrolysin, 7.5 mg/kg, IP). All drugs were administered 30 min before and 24h after MCAO. Both candesartan and glycyrrhizin ameliorated the deleterious effects of MCAO as indicated by the improvement in the performance of the animals in behaviour tests, reduction in brain infarction, neuronal degeneration, and leukocyte infiltration. In addition, MCAO induced a significant upregulation in the different elements of the TLR pathway including TLR-2 and TLR-4, Myd88, TRIF and IRF-3 and the downstream effectors TNF-?, IL-1?, IL-6 and NF-kB. All these changes were significantly ameliorated by treatment with candesartan and glycyrrhizin. The results of the current study represent a new indication for both candesartan and glycyrrhizin in the management of ischemic stroke with effects comparable to those of the standard neuroprotective drug cerebrolysin. PMID:24378346

  4. Mobile-ip Aeronautical Network Simulation Study

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Tran, Diepchi T.

    2001-01-01

    NASA is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This report presents the results of a simulation study of mobile-ip for an aeronautical network. The study was performed to determine the performance of the transmission control protocol (TCP) in a mobile-ip environment and to gain an understanding of how long delays, handoffs, and noisy channels affect mobile-ip performance.

  5. Autophagy in chronically ischemic myocardium

    PubMed Central

    Yan, Lin; Vatner, Dorothy E.; Kim, Song-Jung; Ge, Hui; Masurekar, Malthi; Massover, William H.; Yang, Guiping; Matsui, Yutaka; Sadoshima, Junichi; Vatner, Stephen F.

    2005-01-01

    We tested the hypothesis that chronically ischemic (IS) myocardium induces autophagy, a cellular degradation process responsible for the turnover of unnecessary or dysfunctional organelles and cytoplasmic proteins, which could protect against the consequences of further ischemia. Chronically instrumented pigs were studied with repetitive myocardial ischemia produced by one, three, or six episodes of 90 min of coronary stenosis (30% reduction in baseline coronary flow followed by reperfusion every 12 h) with the non-IS region as control. In this model, wall thickening in the IS region was chronically depressed by ?37%. Using a nonbiased proteomic approach combining 2D gel electrophoresis with in-gel proteolysis, peptide mapping by MS, and sequence database searches for protein identification, we demonstrated increased expression of cathepsin D, a protein known to mediate autophagy. Additional autophagic proteins, cathepsin B, heat shock cognate protein Hsc73 (a key protein marker for chaperone-mediated autophagy), beclin 1 (a mammalian autophagy gene), and the processed form of microtubule-associated protein 1 light chain 3 (a marker for autophagosomes), were also increased. These changes, not evident after one episode, began to appear after two or three episodes and were most marked after six episodes of ischemia, when EM demonstrated autophagic vacuoles in chronically IS myocytes. Conversely, apoptosis, which was most marked after three episodes, decreased strikingly after six episodes, when autophagy had increased. Immunohistochemistry staining for cathepsin B was more intense in areas where apoptosis was absent. Thus, autophagy, triggered by ischemia, could be a homeostatic mechanism, by which apoptosis is inhibited and the deleterious effects of chronic ischemia are limited. PMID:16174725

  6. Preconditioning concepts in polymer flooding in high-salinity reservoirs; Laboratory investigations and case histories

    SciTech Connect

    Volz, H.; Maltin, B.K. (RWE-DEA AG (DE)); Sohn, W.O.

    1990-11-01

    In polymer-flood field projects with partially hydrolized polyacrylamide (PH PAA) solutions, the authors applied two methods of preconditioning: a preflush with fresh water and the use of a relatively small slug of a less-salt-sensitive polymer. Results of laboratory work that led to an improved preconditioning concept with polymer are described. Case histories of two projects with two different preconditioning processes are presented and discussed in detail.

  7. Preconditioning Against Myocardial Dysfunction After Ischemia andReperfusion by an ca1Adrenergic Mechanism

    Microsoft Academic Search

    Anirban Banerjee; Cristee Locke-Winter; Elizabeth C. Brew; Charles B. Cairns; Dennis D. Bensard

    Preconditioning may findreadyapplicability inhumansfacing scheduled global cardiac ischemia- reperfusion (IR)during bypass ortransplantation, wheresucha maneuver isfeasible before arrest. Our objective was todelineate andexploit theendogenous preconditioning mechanismtriggered bytransient ischemia (TI)andthereby attenuate myocardial postischemic mechanical dysfunction byclinically acceptable means. Preconditioning by2 minutesofTIfollowed by10minutesofnormalperfusion protected isolated ratleft ventricle function assessed after 20minutes ofglobal, 37°Cischemia and40 minutesofreperfusion. Finalrecoveryofdeveloped pressure(DP)was improved(91.5±l.9%o of equilibration DP versusunconditioned IRcontrol,

  8. OSI and TCP/IP

    NASA Technical Reports Server (NTRS)

    Randolph, Lynwood P.

    1994-01-01

    The Open Systems Interconnection Transmission Control Protocol/Internet Protocol (OSI TCP/IP) and the Government Open Systems Interconnection Profile (GOSIP) are compared and described in terms of Federal internetworking. The organization and functions of the Federal Internetworking Requirements Panel (FIRP) are discussed and the panel's conclusions and recommendations with respect to the standards and implementation of the National Information Infrastructure (NII) are presented.

  9. [Vascular brain lesions and ischemic heart disease].

    PubMed

    Levin, G Z

    1979-01-01

    The role of essential hypertension in the pathogenesis of cerebral vessel disorders (not only hemorrhagic, but also ischemic) is greater than in the pathogenesis of the heart ischemic disease. An analysis of the evidences left by ancient doctors, when compared with statistical data of our time, gives one grounds to believe that cerebral hemorrhages have been a rather common disease, at least, since the time of the antique civilization of Greece and Rome, whereas ischemic heart disease has become a widespread disease among the population of the developed countries only in our time. This makes it possible to assume that the role of essential hypertension and that of atherosclerosis are not equal in the "diseases of civilization", if the diseases of today's developed society are meant. PMID:494930

  10. Fast IP Handoff Support for VoIP and Multimedia Applications in 802.11 Ioanna Samprakou

    E-print Network

    Bouras, Christos

    Fast IP Handoff Support for VoIP and Multimedia Applications in 802.11 WLANs Ioanna Samprakou Atmel such as voice over IP (VoIP) or video streaming. This paper presents an 802.11-dependent fast IP handoff method which quickly restores IP connectivity for mobile clients running next generation WLAN applications

  11. Mortality and Cause of Death after Hospital Discharge in 10,981 Patients with Ischemic Stroke and Transient Ischemic Attack

    Microsoft Academic Search

    Kazumi Kimura; Kazuo Minematsu; Seiji Kazui; Takenori Yamaguchi

    2005-01-01

    Background: The aim of this study was to examine the 1-year cumulative mortality rate and cause of death, and to identify the predictive factors for death after hospital discharge following ischemic stroke and transient ischemic attack (TIA) using data from the Japan Multicenter Stroke Investigators’ Collaboration study. Methods: We prospectively registered 16,922 consecutive patients with acute ischemic stroke or TIA

  12. 41 CFR 102-72.68 - What preconditions must be satisfied before an Executive agency may exercise the delegated...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...preconditions must be satisfied before an Executive agency may exercise the delegated authority to perform an individual ancillary...preconditions must be satisfied before an Executive agency may exercise the delegated authority to perform an individual...

  13. 41 CFR 102-72.68 - What preconditions must be satisfied before an Executive agency may exercise the delegated...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...preconditions must be satisfied before an Executive agency may exercise the delegated authority to perform an individual ancillary...preconditions must be satisfied before an Executive agency may exercise the delegated authority to perform an individual...

  14. Hypoxia preconditioned mesenchymal stem cells improve vascular and skeletal muscle fiber regeneration after ischemia through a Wnt4 dependent pathway

    E-print Network

    Paris-Sud XI, Université de

    Hypoxia preconditioned mesenchymal stem cells improve vascular and skeletal muscle fiber cell mobilization and skeletal muscle fiber regeneration via a paracrine Wnt dependent mechanism. Transplantation of hypoxic preconditioned murine MSC (HypMSC) enhanced skeletal muscle regeneration at day 7

  15. Ischemic stroke: carotid and vertebral artery disease

    Microsoft Academic Search

    P. Vilela; A. Goulão

    2005-01-01

    Ischemic strokes may have distinct aetiologies, including several different intrinsic arterial pathological disorders. The diagnosis and understanding of these arterial diseases is critical for the correct management of stroke as different treatment approaches are undertaken according to the aetiology. Atherosclerosis is by far the most common arterial disease among adults, and other pathological processes include arterial dissection, small vessel disease,

  16. Cardiac Complications in Acute Ischemic Stroke

    PubMed Central

    Wira, Charles R; Rivers, Emanuel; Martinez-Capolino, Cynthia; Silver, Brian; Iyer, Gayathri; Sherwin, Robert; Lewandowski, Christopher

    2011-01-01

    Introduction To characterize cardiac complications in acute ischemic stroke (AIS) patients admitted from an urban emergency department (ED). Methods Retrospective cross-sectional study evaluating AIS patients admitted from the ED within 24 hours of symptom onset who also had an echocardiogram performed within 72 hours of admission. Results Two hundred AIS patients were identified with an overall in-hospital mortality rate of 8% (n = 16). In our cohort, 57 (28.5%) of 200 had an ejection fraction less than 50%, 35 (20.4%) of 171 had ischemic changes on electrocardiogram (ECG), 18 (10.5%) of 171 presented in active atrial fibrillation, 21 (13.0%) of 161 had serum troponin elevation, and 2 (1.1%) of 184 survivors had potentially lethal arrhythmias on telemetry monitoring. Subgroup analysis revealed higher in-hospital mortality rates among those with systolic dysfunction (15.8% versus 4.9%; P = 0.0180), troponin elevation (38.1% versus 3.4%; P < 0.0001), atrial fibrillation on ECG (33.3% versus 3.8%; P = 0.0003), and ischemic changes on ECG (17.1% versus 6.1%; P = 0.0398) compared with those without. Conclusion A proportion of AIS patients may have cardiac complications. Systolic dysfunction, troponin elevation, atrial fibrillation, or ischemic changes on ECG may be associated with higher in-hospital mortality rates. These findings support the adjunctive role of cardiac-monitoring strategies in the acute presentation of AIS. PMID:22224130

  17. The cell biology of ischemic renal injury

    Microsoft Academic Search

    Joel M Weinberg

    1991-01-01

    Work during the past several years has produced new insights into many aspects of the cell biology of ischemic injury to the tubulointerstitium. The major processes are conveniently considered in terms of early events, the prelethal and lethal cell injuries that occur during the period of ischemia and in the first hours of reperfusion, and late events, the proliferation and

  18. Ischemic stroke penumbra and extracorporeal ozone treatment.

    PubMed

    Wasser, G

    2013-06-01

    The course of events in ischemic strokes is normally seen from a point in which the penumbra is already in place. Since there is no known treatment for edema reduction, mainstream medicine focuses on re-opening the occluded vessel. Here we show that reducing the penumbra saves neuronal units from undergoing apoptosis. PMID:23859279

  19. Primary and Secondary Prevention of Ischemic Stroke

    Microsoft Academic Search

    Maurizio Paciaroni; Julien Bogousslavsky

    2010-01-01

    Prevention of stroke and transient ischemic attack includes both conventional approaches to vascular risk factor management (blood pressure lowering, cholesterol reduction with statins, smoking cessation and antiplatelet therapy) and more specific interventions, such as carotid revascularization or anticoagulation for atrial fibrillation. The objective of this review is to discuss effective interventions for optimal primary and secondary stroke prevention.

  20. Inflammatory mechanisms in ischemic stroke: therapeutic approaches

    Microsoft Academic Search

    Shaheen E Lakhan; Annette Kirchgessner; Magdalena Hofer

    2009-01-01

    Acute ischemic stroke is the third leading cause of death in industrialized countries and the most frequent cause of permanent disability in adults worldwide. Despite advances in the understanding of the pathophysiology of cerebral ischemia, therapeutic options remain limited. Only recombinant tissue-plasminogen activator (rt-PA) for thrombolysis is currently approved for use in the treatment of this devastating disease. However, its

  1. Ischemic Stroke during Pregnancy and Puerperium

    PubMed Central

    Del Zotto, Elisabetta; Giossi, Alessia; Volonghi, Irene; Costa, Paolo; Padovani, Alessandro; Pezzini, Alessandro

    2011-01-01

    Ischemic stroke during pregnancy and puerperium represents a rare occurrence but it could be a serious and stressful event for mothers, infants, and also families. Whenever it does occur, many concerns arise about the safety of the mother and the fetus in relation to common diagnostic tests and therapies leading to a more conservative approach. The physiological adaptations in the cardiovascular system and in the coagulability that accompany the pregnant state, which are more significant around delivery and in the postpartum period, likely contribute to increasing the risk of an ischemic stroke. Most of the causes of an ischemic stroke in the young may also occur in pregnant patients. Despite this, there are specific conditions related to pregnancy which may be considered when assessing this particular group of patients such as pre-eclampsia-eclampsia, choriocarcinoma, peripartum cardiomiopathy, amniotic fluid embolization, and postpartum cerebral angiopathy. This article will consider several questions related to pregnancy-associated ischemic stroke, dwelling on epidemiological and specific etiological aspects, diagnostic issue concerning the use of neuroimaging, and the related potential risks to the embryo and fetus. Therapeutic issues surrounding the use of anticoagulant and antiplatelets agents will be discussed along with the few available reports regarding the use of thrombolytic therapy during pregnancy. PMID:21331336

  2. Steps to translate preconditioning from basic research to the clinic

    PubMed Central

    Bahjat, Frances R; Gesuete, Raffaella; Stenzel-Poore, Mary P

    2012-01-01

    Efforts to treat cardiovascular and cerebrovascular diseases often focus on the mitigation of ischemia-reperfusion (I/R) injury. Many treatments or “preconditioners” are known to provide substantial protection against the I/R injury when administered prior to the event. Brief periods of ischemia itself have been validated as a means to achieve neuroprotection in many experimental disease settings, in multiple organ systems, and in multiple species suggesting a common pathway leading to tolerance. In addition, pharmacological agents that act as potent preconditioners have been described. Experimental induction of neuroprotection using these various preconditioning paradigms has provided a unique window into the brain’s endogenous protective mechanisms. Moreover, preconditioning agents themselves hold significant promise as clinical-stage therapies for prevention of I/R injury. The aim of this article is to explore several key steps involved in the preclinical validation of preconditioning agents prior to the conduct of clinical studies in humans. Drug development is difficult, expensive and relies on multi-factorial analysis of data from diverse disciplines. Importantly, there is no single path for the preclinical development of a novel therapeutic and no proven strategy to ensure success in clinical translation. Rather, the conduct of a diverse array of robust preclinical studies reduces the risk of clinical failure by varying degrees depending upon the relevance of preclinical models and drug pharmacology to humans. A strong sense of urgency and high tolerance of failure are often required to achieve success in the development of novel treatment paradigms for complex human conditions. PMID:23504609

  3. Mobilization of Endogenous Bone Marrow Derived Endothelial Progenitor Cells and Therapeutic Potential of Parathyroid Hormone after Ischemic Stroke in Mice

    PubMed Central

    Wang, Li-Li; Chen, Dongdong; Lee, Jinhwan; Gu, Xiaohuan; Alaaeddine, Ghina; Li, Jimei; Wei, Ling; Yu, Shan Ping

    2014-01-01

    Stroke is a major neurovascular disorder threatening human life and health. Very limited clinical treatments are currently available for stroke patients. Stem cell transplantation has shown promising potential as a regenerative treatment after ischemic stroke. The present investigation explores a new concept of mobilizing endogenous stem cells/progenitor cells from the bone marrow using a parathyroid hormone (PTH) therapy after ischemic stroke in adult mice. PTH 1-34 (80 µg/kg, i.p.) was administered 1 hour after focal ischemia and then daily for 6 consecutive days. After 6 days of PTH treatment, there was a significant increase in bone marrow derived CD-34/Fetal liver kinase-1 (Flk-1) positive endothelial progenitor cells (EPCs) in the peripheral blood. PTH treatment significantly increased the expression of trophic/regenerative factors including VEGF, SDF-1, BDNF and Tie-1 in the brain peri-infarct region. Angiogenesis, assessed by co-labeled Glut-1 and BrdU vessels, was significantly increased in PTH-treated ischemic brain compared to vehicle controls. PTH treatment also promoted neuroblast migration from the subventricular zone (SVZ) and increased the number of newly formed neurons in the peri-infarct cortex. PTH-treated mice showed significantly better sensorimotor functional recovery compared to stroke controls. Our data suggests that PTH therapy improves endogenous repair mechanisms after ischemic stroke with functional benefits. Mobilizing endogenous bone marrow-derived stem cells/progenitor cells using PTH and other mobilizers appears an effective and feasible regenerative treatment after ischemic stroke. PMID:24503654

  4. Weighted graph based ordering techniques for preconditioned conjugate gradient methods

    NASA Technical Reports Server (NTRS)

    Clift, Simon S.; Tang, Wei-Pai

    1994-01-01

    We describe the basis of a matrix ordering heuristic for improving the incomplete factorization used in preconditioned conjugate gradient techniques applied to anisotropic PDE's. Several new matrix ordering techniques, derived from well-known algorithms in combinatorial graph theory, which attempt to implement this heuristic, are described. These ordering techniques are tested against a number of matrices arising from linear anisotropic PDE's, and compared with other matrix ordering techniques. A variation of RCM is shown to generally improve the quality of incomplete factorization preconditioners.

  5. IP traffic grooming over WDM optical networks

    Microsoft Academic Search

    Jing Fang; Arun K. Somani

    2005-01-01

    IP over WDM has emerged as a winning network architecture to facilitate today's IP centric Internet. Although the total amount of bandwidth demands keeps increasing, there still exists a huge gap between the increasing full-wavelength capacity and the existing low-rate IP traffic. Efficiently grooming low-rate traffic stream to high-capacity lightpaths helps to alleviate the bandwidth mismatch, effectively improve the network

  6. Voice over IP: Risks, Threats and Vulnerabilities

    Microsoft Academic Search

    Angelos D. Keromytis

    Voice over IP (VoIP) and Internet Multimedia Subsystem (IMS) technologies are rapidly being adopted by consumers, enterprises, governments and militaries. These tech- nologies offer higher flexibility and more features than tra ditional telephony (PSTN) infrastructures, as well as the potential for lower cost through equipment consolidation and, for the con- sumer market, new business models. However, VoIP\\/IMS systems also represent

  7. Transformational IP Services over Transponded SATCOM (TIPSOTS)

    Microsoft Academic Search

    Jay Hicks; Jerry Rippon; Daniel Gray; David Fritz; Jeff Ruff

    2007-01-01

    TIPSOTS provides a roadmap to transform existing link-based satellite networks into IP-based networks as part of integration into the Global Information Grid (GIG). TIPSOTS provides a Net-Centric operational capabilities using IP-packet switched bandwidth-on-demand based architecture. TIPSOTS architecture defines the various components that makeup the Wideband network and control in addition to developing standards for shared access IP modems for use

  8. Preconditioned Krylov subspace methods for solving nonsymmetric matrices from CFD applications q

    E-print Network

    Zhang, Jun

    Preconditioned Krylov subspace methods for solving nonsymmetric matrices from CFD applications q dynamics (CFD) applications. The preconditioned iterative methods consist of Krylov subspace accelerators matrices arising from various relevant CFD applications, are reported. Ó 2000 Elsevier Science S.A. All

  9. A preconditioning mass matrix to accelerate the convergence to the steady Euler solutions using explicit schemes

    Microsoft Academic Search

    M. A. Storti; C. E. Baumann; S. R. Idelsohn

    1992-01-01

    The paper shows, with analytical and numerical results, how the use of a preconditioning mass matrix accelerates the convergence in zones with low Mach number and in zones with transonic flow. A preconditioning mass matrix is proposed which can be applied to any FEM\\/FVM that uses an explicit time marching scheme to find the steady state. The method's rate of

  10. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  11. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  12. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  13. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  14. HL-1 Myocytes Exhibit PKC and KATP Channel-Dependent Delta Opioid Preconditioning1,2

    E-print Network

    Wojcik, Edward J.

    HL-1 Myocytes Exhibit PKC and KATP Channel-Dependent Delta Opioid Preconditioning1,2 Elisabeth M. Opioid preconditioning protects the myocardium against ischemia/reperfusion (IR) injury. By enhancing cardiomyocyte viability, opioids can en- hance cardiac function and recovery from IR injury during acute cardiac

  15. Preconditioning via a Schur Complement Method: an Application in State Estimation

    E-print Network

    Blank, Luise - Naturwissenschaftliche Fakultät I

    Preconditioning via a Schur Complement Method: an Application in State Estimation #3; Luise Blank y complement is analyzed and applied for preconditioning symmetric matrices. In particular we eliminate the in modulo extreme eigenvalues by computing the Schur complement with respect to a coarse subspace, which cap

  16. An incomplete-factorization preconditioning using repeated red-black ordering

    Microsoft Academic Search

    Clemens W. Brand

    1992-01-01

    Summary The convergence of the conjugate gradient method for the iterative solution of large systems of linear equations depends on proper preconditioning matrices. We present an efficient incomplete-factorization preconditioning based on a specific, “repeated red-black” ordering scheme and cyclic reduction. For the Dirichlet model problem, we prove that the condition number increases asymptotically slower with the number of equations than

  17. Waveform preconditioning for clutter rejection in multipath for sparse distributed apertures

    Microsoft Academic Search

    T. Varslot; B. Yazici; C.-E. Yarman; M. Cheney; L. Scharf

    2007-01-01

    The idea of preconditioning transmit waveforms for optimal clutter rejection in radar imaging is presented. Waveform preconditioning involves determining a map on the space of transmit waveforms, and then applying this map to the waveforms before transmission. The work applies to systems with an arbitrary number of transmitand receive-antenna elements, and makes no assumptions about the elements being co-located. Waveform

  18. IP3 Receptors: Toward Understanding Their Activation

    PubMed Central

    Taylor, Colin W.; Tovey, Stephen C.

    2010-01-01

    Inositol 1,4,5-trisphosphate receptors (IP3R) and their relatives, ryanodine receptors, are the channels that most often mediate Ca2+ release from intracellular stores. Their regulation by Ca2+ allows them also to propagate cytosolic Ca2+ signals regeneratively. This brief review addresses the structural basis of IP3R activation by IP3 and Ca2+. IP3 initiates IP3R activation by promoting Ca2+ binding to a stimulatory Ca2+-binding site, the identity of which is unresolved. We suggest that interactions of critical phosphate groups in IP3 with opposite sides of the clam-like IP3-binding core cause it to close and propagate a conformational change toward the pore via the adjacent N-terminal suppressor domain. The pore, assembled from the last pair of transmembrane domains and the intervening pore loop from each of the four IP3R subunits, forms a structure in which a luminal selectivity filter and a gate at the cytosolic end of the pore control cation fluxes through the IP3R. PMID:20980441

  19. Ischemic tolerance is associated with VEGF-C and VEGFR-3 signaling in the mouse hippocampus.

    PubMed

    Bhuiyan, M I H; Kim, J-C; Hwang, S-N; Lee, M-Y; Kim, S Y

    2015-04-01

    The functions of vascular endothelial growth factor C (VEGF-C) and the VEGF receptor 3 (VEGFR-3) in the nervous system are not well known. In this study, we examined the role of VEGF-C and VEGFR-3 in ischemic preconditioning (IPC)-induced tolerance in the mouse hippocampus. Adult male C57BL/6 mice were subjected to either severe ischemia (SI) induced by 40 min of bilateral common carotid artery occlusion (BCCAO) with or without IPC (5-min BCCAO) or IPC only. Cerebral blood flow was measured during ischemic periods using laser Doppler flowmetry. Neuronal damage was assessed histologically, and VEGF-C and VEGFR-3 expression levels were assessed through immunostaining. Fluoro-Jade B-labeled cells were abundant in the CA1 area 7 days after SI without IPC (sham+SI group), whereas cells were rarely labeled in mice subjected to IPC followed by SI (IPC+SI group). Similarly, the number of neuronal nuclei (NeuN)-positive cells in the CA1 area was significantly lower in the sham+SI group than in the IPC+SI group. Interestingly, we found that sublethal IPC treatment induced prominent VEGF-C expression in the CA1 pyramidal neurons and VEGFR-3 expression in the stratum radiatum and stratum lacunosum moleculare after 3 days of reperfusion that were sustained for 7 days. Moreover, VEGF-C immunoreactivity was also markedly increased, whereas VEGFR-3 expression was sustained in tolerance-acquired CA1 neurons after SI. Application of a VEGFR-3 inhibitor, SAR131675, abolished the IPC-induced neuroprotection in a dose-dependent manner in the mouse hippocampus. These results suggest that VEGF-C/VEGFR-3 signaling is associated with IPC-induced hippocampal tolerance to lethal ischemia. PMID:25637798

  20. Impact of Severe Extracranial ICA Stenosis on MRI Perfusion and Diffusion Parameters in Acute Ischemic Stroke

    PubMed Central

    Kaesemann, Philipp; Thomalla, Götz; Cheng, Bastian; Treszl, Andras; Fiehler, Jens; Forkert, Nils Daniel

    2014-01-01

    Purpose: The aim of this study was to investigate the impact of a coexisting internal carotid artery (ICA) stenosis on lesion volumes as well as diffusion and perfusion parameters in acute ischemic stroke resulting from middle cerebral artery (MCA) occlusion. Material and methods: Magnetic resonance imaging data of 32 patients with MCA occlusion with or without additional ICA stenosis imaged within 4.5?h of symptom onset were analyzed. Both groups consisted of 16 patients. Acute diffusion lesions were semi-automatically segmented in apparent diffusion coefficient (ADC) MRI datasets. Perfusion maps of cerebral blood volume (CBV), cerebral blood flow, mean transit time and Tmax were calculated using perfusion-weighted MRI datasets. Tissue-at-risk (TAR) volumes were generated by subtracting the ADC lesion from the hypoperfusion lesion defined by Tmax >6?s. Median ADC and perfusion parameter values were extracted separately for the diffusion lesion and TAR and used for statistical analysis. Results: No significant differences were found between the groups regarding the diffusion lesion and TAR volumes. Statistical analysis of diffusion and perfusion parameters revealed CBV as the only parameter with a significant difference (p?=?0.009) contributing a small effect (?2?=?0.11) to the group comparison with higher CBV values for the patient group with a coexisting ICA stenosis, while no significant effects were found for the other diffusion and perfusion parameters analyzed. Conclusion: The results of this study suggest that a coexisting ICA stenosis does not have a strong effect on tissue status or perfusion parameters in acute stroke patients except for a moderate elevation of CBV. This may reflect improved collateral circulation or ischemic preconditioning in patients with a pre-existing proximal stenosis balancing impaired perfusion from the stenosis. PMID:25538674

  1. The Spacelab IPS Star Simulator

    NASA Technical Reports Server (NTRS)

    Wessling, Francis C., III

    1993-01-01

    The cost of doing business in space is very high. If errors occur while in orbit the costs grow and desired scientific data may be corrupted or even lost. The Spacelab Instrument Pointing System (IPS) Star Simulator is a unique test bed that allows star trackers to interface with simulated stars in a laboratory before going into orbit. This hardware-in-the loop testing of equipment on earth increases the probability of success while in space. The IPS Star Simulator provides three fields of view 2.55 x 2.55 degrees each for input into star trackers. The fields of view are produced on three separate monitors. Each monitor has 4096 x 4096 addressable points and can display 50 stars (pixels) maximum at a given time. The pixel refresh rate is 1000 Hz. The spectral output is approximately 550 nm. The available relative visual magnitude range is 2 to 8 visual magnitudes. The star size is less than 100 arc seconds. The minimum star movement is less than 5 arc seconds and the relative position accuracy is approximately 40 arc seconds. The purpose of this paper is to describe the LPS Star Simulator design and to provide an operational scenario so others may gain from the approach and possible use of the system.

  2. An integrated software system for analyzing ChIP-chip and ChIP-seq data

    Microsoft Academic Search

    Hongkai Ji; Hui Jiang; Wenxiu Ma; David S Johnson; Richard M Myers; Wing H Wong

    2008-01-01

    We present CisGenome, a software system for analyzing genome-wide chromatin immunoprecipitation (ChIP) data. CisGenome is designed to meet all basic needs of ChIP data analyses, including visualization, data normalization, peak detection, false discovery rate computation, gene-peak association, and sequence and motif analysis. In addition to implementing previously published ChIP–microarray (ChIP-chip) analysis methods, the software contains statistical methods designed specifically for

  3. ASIC design of fast IP-lookup for next generation IP router

    Microsoft Academic Search

    Yuan-sun Chu; Po-feng Lin; Jia-huang Lin; Hui-kai Su; Ming-jen Chen

    2005-01-01

    One of the prime designs for the next generation IP routers is the IP-lookup mechanism. The IP lookup has become a major performance bottleneck for the routers. In this paper, we propose a complete hardware architecture which includes searching, updating, inserting, and deleting functions. A simple hash hardware design is used to reduce the lookup time, and a CAM is

  4. Parallelizable approximate solvers for recursions arising in preconditioning

    SciTech Connect

    Shapira, Y. [Israel Inst. of Technology, Haifa (Israel)

    1996-12-31

    For the recursions used in the Modified Incomplete LU (MILU) preconditioner, namely, the incomplete decomposition, forward elimination and back substitution processes, a parallelizable approximate solver is presented. The present analysis shows that the solutions of the recursions depend only weakly on their initial conditions and may be interpreted to indicate that the inexact solution is close, in some sense, to the exact one. The method is based on a domain decomposition approach, suitable for parallel implementations with message passing architectures. It requires a fixed number of communication steps per preconditioned iteration, independently of the number of subdomains or the size of the problem. The overlapping subdomains are either cubes (suitable for mesh-connected arrays of processors) or constructed by the data-flow rule of the recursions (suitable for line-connected arrays with possibly SIMD or vector processors). Numerical examples show that, in both cases, the overhead in the number of iterations required for convergence of the preconditioned iteration is small relatively to the speed-up gained.

  5. Role of miRs in Cardiac Preconditioning

    PubMed Central

    Salloum, Fadi N.; Yin, Chang; Kukreja, Rakesh C.

    2014-01-01

    Preconditioning of the heart by sub-lethal ischemia, mild heat shock or hypoxia have evolved as powerful experimental tools to discover novel signaling mechanisms in cardioprotection. The ultimate goal is to determine novel therapeutic targets for potential application in humans in protecting the heart against ischemia-related injuries. In recent years, there has been a tremendous interest in understanding the role of small non-coding RNAs, microRNAs (miRs), in cardiovascular diseases. miRs have been recognized as regulators of gene expression by destabilization and translational inhibition of target mRNAs. Studies have shown that several miRs including miR-1, miR-133, miR-21, miR-126, miR-320, miR-92a and miR-199a are regulated after preconditioning and play an active role in protection of the heart against ischemia/reperfusion injury. These miRs also drive the synthesis of important cardioprotective proteins including HSP-70, eNOS, iNOS, HSP-20, Sirt-1 and HIF-1?. We believe that identification and targeted delivery of miR(s) in the heart could have an immense therapeutic potential in reducing myocardial infarction in patients suffering from heart disease. PMID:20980922

  6. Evidence for an essential role of reactive oxygen species in the genesis of late preconditioning against myocardial stunning in conscious pigs.

    PubMed Central

    Sun, J Z; Tang, X L; Park, S W; Qiu, Y; Turrens, J F; Bolli, R

    1996-01-01

    Conscious pigs underwent a sequence of 10 2-min coronary occlusions, each separated by 2 min of reperfusion, for three consecutive days (days 1, 2, and 3). On day 1, pigs received an i.v. infusion of a combination of antioxidants (superoxide dismutase, catalase, and N-2 mercaptopropionyl glycine; group II, n = 9), nisoldipine (group III, n = 6), or vehicle (group I [controls], n = 9). In the control group, systolic wall thickening (WTh) in the ischemic-reperfused region on day 1 remained significantly depressed for 4 h after the 10th reperfusion, indicating myocardial "stunning." On days 2 and 3, however, the recovery of WTh improved markedly, so that the total deficit of WTh decreased by 53% on day 2 and 56% on day 3 compared with day 1 (P < 0.01), indicating the development of a powerful cardioprotective response (late preconditioning against stunning). In the anti-oxidant-treated group, the total deficit of WTh on day 1 was 54% less than in the control group (P < 0.01). On day 2, the total deficit of WTh was 85% greater than that observed on day 1 and similar to that observed on day 1 in the control group. On day 3, the total deficit of WTh was 58% less than that noted on day 2 (P < 0.01). In the nisoldipine-treated group, the total deficit of WTh on day 1 was 53% less than that noted in controls (P < 0.01). On days 2 and 3, the total deficit of WTh was similar to the corresponding values in the control group. These results demonstrate that: (a) in the conscious pig, antioxidant therapy completely blocks the development of late preconditioning against stunning, indicating that the production of reactive oxygen species (ROS) on day 1 is the mechanism whereby ischemia induces the protective response observed on day 2; (b) antioxidant therapy markedly attenuates myocardial stunning on day 1, indicating that ROS play an important pathogenetic role in postischemic dysfunction in the porcine heart despite the lack of xanthine oxidase; (c) although the administration of a calcium-channel antagonist (nisoldipine) is as effective as antioxidant therapy in attenuating myocardial stunning on day 1, it has no effect on late preconditioning on day 2, indicating that the ability of antioxidants to block late preconditioning is not a nonspecific result of the mitigation of postischemic dysfunction on day 1. Generation of ROS during reperfusion is generally viewed as a deleterious process. Our finding that ROS contribute to the genesis of myocardial stunning but, at the same time, trigger the development of late preconditioning against stunning supports a complex pathophysiological paradigm, in which ROS play an immediate injurious role (as mediators of stunning) followed by a useful function (as mediators of subsequent preconditioning). PMID:8567981

  7. On the Energy Efficiency of IP-over-WDM Networks

    E-print Network

    Bregni, Stefano

    On the Energy Efficiency of IP-over-WDM Networks S. Bregni, Senior Member, IEEE, V. Grkovi, F transport networks. We compare three different architectures for IP packet transport based on Wavelength Division Multiplexing (WDM) over optical fiber links (IP-over-WDM networks), namely IP with no Bypass (IP

  8. Empirical Tests of Anonymous Voice Over IP Marc Liberatoreb,

    E-print Network

    Wright , Matthew

    Empirical Tests of Anonymous Voice Over IP Marc Liberatoreb, , Bikas Gurunga , Brian Neil Levineb IP, privacy, traffic analysis Abstract. Voice over IP (VoIP) is an important service on the Internet, and privacy for VoIP calls will be increasingly important for many people. Providing this privacy, however

  9. Wireless Networks III, Fall 04 Lecture 1. IP Mobility Support

    E-print Network

    Schwefel, Hans-Peter

    Wireless Networks III, Fall 04 Lecture 1. IP Mobility Support Exercises 1. MIP Performance Aspects bytes for Layer 3 and higher. The CN and the MH establish a bi-directional VoIP session (via UDP/IP network (assuming IP in IP tunneling)? o How does the latter change if minimal encapsulation is used

  10. Wireless Data Communication, Fall 03 Lecture 2. IP Mobility Support

    E-print Network

    Schwefel, Hans-Peter

    Wireless Data Communication, Fall 03 Lecture 2. IP Mobility Support Exercises 1. MIP Performance header bytes for Layer 3 and higher. The CN and the MH establish a bi-directional VoIP session (via UDP/IP network (assuming IP in IP tunneling)? o How does the latter change if minimal encapsulation is used

  11. iproute2-ss020116 1 IP Command Reference.

    E-print Network

    Mellia, Marco

    iproute2-ss020116 1 IP Command Reference. Alexey N. Kuznetsov Institute for Nuclear Research, Moscow kuznet@ms2.inr.ac.ru April 14, 1999 Contents 1 About this document 3 2 ip -- command syntax 3 3 ip -- error messages 5 4 ip link -- network device configuration 6 4.1 ip link set -- change device attributes

  12. Routage IP au niveau h^ote Philippe Langevin

    E-print Network

    Faccanoni, Gloria

    Routage IP au niveau h^ote Philippe Langevin Oct 2007, Nov 2008, Nov 2011. #12;Protocole IP Interface r´eseau Routeur Livraison physique Routage IP Adresse multicast Filtrage et translation d'adresse Algorithme de routage Travaux-Pratiques #12;Mod`ele TCP/IP Le protocole IP (Internet Protocole) constitue la

  13. IP Traceback Using DNS Logs against Bots

    Microsoft Academic Search

    Keisuke TAKEMORI; Masahiko FUJINAGA; Toshiya SAYAMA; Masakatsu NISHIGAKI

    2008-01-01

    Source IP spoofing attacks are critical issues to the Internet. These attacks are considered to be sent from bot infected hosts. There has been active research on IP traceback technologies. However, the traceback from an end victim host to an end spoofing host has not yet been achieved, due to the lack of traceback probes installed on each routing path.

  14. IP connectivity for gateway GPRS support node

    Microsoft Academic Search

    Yuan-Kai Chen; Yi-bing Lin

    2005-01-01

    In the Universal Mobile Telecommunications System, the gateway GPRS support node (GGSN) provides IP connection between the mobile telecommunications network and external packet data networks (e.g., the Internet). Specifically, the GGSN exercises session management to transfer user packets between mobile stations and external data networks. In this article we focus on the GGSN functions for IP connection including access point

  15. Scalable High Speed IP Routing Lookups

    Microsoft Academic Search

    Marcel Waldvogel; George Varghese; Jonathan S. Turner; Bernhard Plattner

    1997-01-01

    Internet address lookup is a challenging problem because of increasing routing table sizes, increased traffic, higher speed links, and the migration to 128 bit IPv6 addresses. IP routing lookup requires computing the best matching prefix, for which standard solutions like hashing were believed to be inapplicable. The best existing solution we know of, BSD radix tries, scales badly as IP

  16. Congestion control in IP\\/TCP internetworks

    Microsoft Academic Search

    John Nagle

    1984-01-01

    Congestion control is a recognized problem in complex networks. We have discovered that the Department of Defense's Internet Protocol (IP), a pure datagram protocol, and Transmission Control Protocol (TCP), a transport layer protocol, when used together, are subject to unusual congestion problems caused by interactions between the transport and datagram layers. In particular, IP gateways are vulnerable to a phenomenon

  17. Congestion control in IP\\/TCP internetworks

    Microsoft Academic Search

    John Nagle

    1995-01-01

    Congestion control is a recognized problem in complex networks. We have discovered that the Department of Defense's Internet Protocol (IP), a pure datagram protocol, and Transmission Control Protocol (TCP), a transport layer protocol, when used together, are subject to unusual congestion problems caused by interactions between the transport and datagram layers. In particular, IP gateways are vulnerable to a phenomenon

  18. Mobile IP and virtual private networks

    Microsoft Academic Search

    Ravi Bhagavathula; Nagaraja Thanthry; Ravi Pendse

    2002-01-01

    With a growing number of portable computing devices like laptops and personal digital assistants (PDA), the need for seamless connectivity to the global Internet is driving the acceptance of different mobility solutions. Mobile IP is one of the widely accepted mobility solutions for mobile nodes. Though mobile IP caters the seamless connectivity requirements of the mobile nodes, the issues regarding

  19. Adjusted Probabilistic Packet Marking for IP Traceback

    Microsoft Academic Search

    Tao Peng; Christopher Leckie; Kotagiri Ramamohanarao

    2002-01-01

    Distributed denial-of-service attack is one of the greatest threats to the Internet today. One of the biggest difficulties in defending against this attack is that attackers always use incorrect, or "spoofed" IP source addresses to disguise their true origin. In this paper, we present a packet marking algorithm which allows the victim to traceback the approximate origin of spoofed IP

  20. IP Fault Localization Via Risk Modeling

    Microsoft Academic Search

    Ramana Rao Kompella; Jennifer Yates; Albert G. Greenberg; Alex C. Snoeren

    2005-01-01

    Automated, rapid, and effective fault management is a central goal of large operational IP networks. Today's networks suffer from a wide and volatile set of failure modes, where the underlying fault proves difficult to de- tect and localize, thereby delaying repair. One of the main challenges stems from operational reality: IP rout- ing and the underlying optical fiber plant are

  1. Steganography of VoIP Streams

    Microsoft Academic Search

    Wojciech Mazurczyk; Krzysztof Szczypiorski

    2008-01-01

    The paper concerns available steganographic techni ques that can be used for creating covert channels for VoIP (Voice o ver Internet Protocol) streams. Apart from characterizing existing stegano graphic methods we provide new insights by presenting two new techniques. The first one is network stega- nography solution which exploits free\\/unused protoc ols' fields and is known for IP, UDP or

  2. Link layer assisted IP mobility protocol

    Microsoft Academic Search

    Guo-Yuan Mikko Wang; Chunhung Richard Lin

    2005-01-01

    As the popularity of IEEE 802.11 rises, many problems have been arisen that were absent in the traditional wired networks. A serious problem has arrived from the movement of mobile nodes - this mobility characteristic will make the data transmission mechanisms differ from before. A general solution to this problem is mobile IP. But mobile IP in itself has problems

  3. Nymble: Anonymous IP-Address Blocking

    Microsoft Academic Search

    Peter C. Johnson; Apu Kapadia; Patrick P. Tsang; Sean W. Smith

    2007-01-01

    Anonymizing networks such as Tor allow users to access Internet ser- vices privately using a series of routers to hide the client's IP address from the server. Tor's success, however, has been limited by users employing this anonymity for abusive purposes, such as defacing Wikipedia. Website administrators rely on IP- address blocking for disabling access to misbehaving users, but this

  4. A Fast IP Routing Lookup Scheme

    Microsoft Academic Search

    Pi-chung Wang; Yaw-chung Chen; Chia-tai Chan

    2000-01-01

    Abstract—A major issue in router design for the next genera- tion Internet is the fast IP address lookup mechanism. The existing scheme by Huang et al. performs the IP address lookup in hard- ware in which the forwarding table can be compressed to fit into reasonable-size SRAM, and a lookup can be accomplished in three memory accesses. In this letter,

  5. Guidelines for Management of IP Address Space

    Microsoft Academic Search

    E. Gerich

    1992-01-01

    This document has been reviewed by the Federal Engineering Task Force (FEPG) on behalf of the Federal Networking Council (FNC), the co- chairs of the International Engineering Planning Group (IEPG), and the Reseaux IP Europeens (RIPE). There was general consensus by those groups to support the recommendations proposed in this document for management of the IP address space.

  6. IP Address Handoff in the MANET

    Microsoft Academic Search

    Hongbo Zhou; Matt W. Mutka; Lionel M. Ni

    2004-01-01

    When compared with a fixed host that is connected to a hardwired network, a mobile node in the MANET may change its IP address more frequently due to the deployment of autoconfiguration, global connectivity, and hierarchical addressing schemes. When an IP address changes, the performance of unicast routing protocols and real-time communications may degrade, and privacy may be compromised within

  7. DEMOMSTRATION OF IP CLIENT-TO-IP CLIENT PACKET TRANSPORT OVER AN OPTICAL LABEL-SWITCHING NETWORK

    E-print Network

    Kolner, Brian H.

    DEMOMSTRATION OF IP CLIENT-TO-IP CLIENT PACKET TRANSPORT OVER AN OPTICAL LABEL-SWITCHING NETWORK and routing of traffic from IP client-to-IP client through a multi-hop optical label-switching network. Edge routers generate optical labels and achieve interconnection between IP clients across the network

  8. First Experimental Demonstration of IP-client-to-IP-client Video Streaming Application over an All-Optical Label-

    E-print Network

    Kolner, Brian H.

    First Experimental Demonstration of IP-client-to-IP-client Video Streaming Application over an All knowledge, successful transmission and switching of video streaming traffic from an IP-client to an IP.4250) Networks, (060.4510) Optical communications 1. Introduction IP-over-optical is a novel concept that has

  9. Space Network IP Services (SNIS): An Architecture for Supporting Low Earth Orbiting IP Satellite Missions

    NASA Technical Reports Server (NTRS)

    Israel, David J.

    2005-01-01

    The NASA Space Network (SN) supports a variety of missions using the Tracking and Data Relay Satellite System (TDRSS), which includes ground stations in White Sands, New Mexico and Guam. A Space Network IP Services (SNIS) architecture is being developed to support future users with requirements for end-to-end Internet Protocol (IP) communications. This architecture will support all IP protocols, including Mobile IP, over TDRSS Single Access, Multiple Access, and Demand Access Radio Frequency (RF) links. This paper will describe this architecture and how it can enable Low Earth Orbiting IP satellite missions.

  10. Red spectroscopy of IP Pegasi

    NASA Astrophysics Data System (ADS)

    Martin, J. S.; Jones, D. H. P.; Smith, R. C.

    1987-02-01

    Time resolved spectroscopy of the dwarf nova IP Pegasi in the range ??7670 - 8320 Å shows absorption lines originating from the cool secondary. A radial velocity curve for this component has been derived by cross-correlation with a normal M star. The curve has semi-amplitude K2 = 288.3±4 km s-1, and is slightly distorted. This distortion is equivalent to an orbit with an apparent eccentricity of 0.075±0.024. The mass function of the primary is 0.394±0.016 M_sun;. From this the authors derive constraints on the component masses of 0.62 < M1 < 1.14 M_sun; and 0.17 < M2 < 0.71 M_sun;. The red star has a radius in the range 0.32 < R2 < 0.51 R_sun; and is probably on the main sequence.

  11. Estrogen, neuroprotection and neurogenesis after ischemic stroke.

    PubMed

    Shao, Bei; Cheng, Yifan; Jin, Kunlin

    2012-02-01

    Stroke is the third most common cause of death, particularly of the elderly. Despite considerable advances in knowledge about the mechanisms of cell death after stroke, a treatment for stroke remains exclusive. For a long time, estrogen was thought of only as a "sex hormone". Studies have documented that estrogen plays an important role in regulating behavioral and physiological events beyond the reproductive system. Most animal studies have shown that estrogens exert neuroprotective and neurogenesis effects in vivo and in vitro after ischemic stroke. However, clinical and epidemiological evidence shows that estrogen increases the risk of coronary heart disease, stroke, and breast cancer. The discrepancy between animal studies and clinical data emphasizes the importance of performing further investigations using appropriate animal models, and gaining a deeper understanding of the mechanisms of estrogen-mediated neuroprotection and neurogenesis. This review focuses on recent advances in estrogen-mediated neuroprotection and neurogenesis after ischemic stroke, highlighting its potential molecular and cellular mechanisms. PMID:22204318

  12. Linking Notch signaling to ischemic stroke

    PubMed Central

    Arboleda-Velasquez, Joseph F.; Zhou, Zhipeng; Shin, Hwa Kyoung; Louvi, Angeliki; Kim, Hyung-Hwan; Savitz, Sean I.; Liao, James K.; Salomone, Salvatore; Ayata, Cenk; Moskowitz, Michael A.; Artavanis-Tsakonas, Spyros

    2008-01-01

    Vascular smooth muscle cells (SMCs) have been implicated in the pathophysiology of stroke, the third most common cause of death and the leading cause of long-term neurological disability in the world. However, there is little insight into the underlying cellular pathways that link SMC function to brain ischemia susceptibility. Using a hitherto uncharacterized knockout mouse model of Notch 3, a Notch signaling receptor paralogue highly expressed in vascular SMCs, we uncover a striking susceptibility to ischemic stroke upon challenge. Cellular and molecular analyses of vascular SMCs derived from these animals associate Notch 3 activity to the expression of specific gene targets, whereas genetic rescue experiments unambiguously link Notch 3 function in vessels to the ischemic phenotype. PMID:18347334

  13. The sulfated polysaccharide fucoidan rescues senescence of endothelial colony-forming cells for ischemic repair.

    PubMed

    Lee, Jun Hee; Lee, Sang Hun; Choi, Sung Hyun; Asahara, Takayuki; Kwon, Sang-Mo

    2015-06-01

    The efficacy of cell therapy using endothelial colony-forming cells (ECFCs) in the treatment of ischemia is limited by the replicative senescence of isolated ECFCs in vitro. Such senescence must therefore be overcome in order for such cell therapies to be clinically applicable. This study aimed to investigate the potential of sulfated polysaccharide fucoidan to rescue ECFCs from cellular senescence and to improve in vivo vascular repair by ECFCs. Fucoidan-preconditioning of senescent ECFCs was shown by flow cytometry to restore the expression of functional ECFC surface markers (CD34, c-Kit, VEGFR2, and CXCR4) and stimulate the in vitro tube formation capacity of ECFCs. Fucoidan also promoted the expression of cell cycle-associated proteins (cyclin E, Cdk2, cyclin D1, and Cdk4) in senescent ECFCs, significantly reversed cellular senescence, and increased the proliferation of ECFCs via the FAK, Akt, and ERK signaling pathways. Fucoidan was found to enhance the survival, proliferation, incorporation, and endothelial differentiation of senescent ECFCs transplanted in ischemic tissues in a murine hind limb ischemia model. Moreover, ECFC-induced functional recovery and limb salvage were markedly improved by fucoidan pretreatment of ECFCs. To our knowledge, the findings of our study are the first to demonstrate that fucoidan enhances the neovasculogenic potential of ECFCs by rescuing them from replicative cellular senescence. Pretreatment of ECFCs with fucoidan may thus provide a novel strategy for the application of senescent stem cells to therapeutic neovascularization. Stem Cells 2015;33:1939-1951. PMID:25693733

  14. Advances in treatment of acute ischemic stroke

    Microsoft Academic Search

    Italo Linfante; Nabil M. Akkawi

    2006-01-01

    Stroke carries a severe toll in terms of loss of life and disability for patients and their families. Until 10 years ago,\\u000a physicians, and in particular neurologists, had a conservative, nonaggresive approach to this devastating disease. The advent\\u000a of thrombolytic therapy not only proved that acute ischemic stroke is treatable, but also that early reperfusion can dramatically\\u000a change the outcome

  15. Quantitative prediction of ischemic stroke tissue fate

    Microsoft Academic Search

    Qiang Shen; Timothy Q. Duong

    2008-01-01

    Accurate prediction of ischemic tissue fate could aid clinical decision-making in the treatment of acute stroke. We investigated predictions of tissue fate for three (30-min, 60-min and permanent) stroke models in rats. Quantitative cerebral blood flow (CBF), apparent diffusion coefficient (ADC) and spin-spin relaxation time constant (T2) were acquired during the acute phase and at the end point followed by

  16. Systemic Reperfusion Therapy in Acute Ischemic Stroke

    Microsoft Academic Search

    P. Martínez-Sánchez; E. Díez-Tejedor; B. Fuentes; W. Hacke

    2007-01-01

    Introduction: Experimental and clinical studies indicate that early reperfusion of occluded brain-supplying arteries reduces the size of injury and improves outcome. Recombinant tissue plasminogen activator (t-PA) is the only drug approved for systemic reperfusion in acute ischemic stroke. However, the use of intravenous t-PA is currently limited by its narrow therapeutic window. Methods: We reviewed the approaches to extending systemic

  17. Ischemic Colitis in an Endurance Runner

    PubMed Central

    Grames, Chase; Berry-Cabán, Cristóbal S.

    2012-01-01

    A 20-year-old female running the Marine Corps Marathon developed diarrhea at mile 12. After finishing the race she noted that she was covered in bloody stool. A local emergency department suspected ischemic colitis. After discharge, her primary care physician instructed her to discontinue the use of all nonsteroidal anti-inflammatory drugs. Her symptoms resolved and she returned to running without any complications. This paper describes the pathophysiology, diagnostic approach, and management options. PMID:23091744

  18. Exercise preconditioning of myocardial infarct size in dogs is triggered by calcium.

    PubMed

    Parra, Víctor M; Macho, Pilar; Sánchez, Gina; Donoso, Paulina; Domenech, Raúl J

    2015-03-01

    We showed that exercise induces early and late myocardial preconditioning in dogs and that these effects are mediated through nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase activation. As the intracoronary administration of calcium induces preconditioning and exercise enhances the calcium inflow to the cell, we studied if this effect of exercise triggers exercise preconditioning independently of its hemodynamic effects. We analyzed in 81 dogs the effect of blocking sarcolemmal L-type Ca channels with a low dose of verapamil on early and late preconditioning by exercise, and in other 50 dogs, we studied the effect of verapamil on NADPH oxidase activation in early exercise preconditioning. Exercise reduced myocardial infarct size by 76% and 52% (early and late windows respectively; P < 0.001 both), and these effects were abolished by a single low dose of verapamil given before exercise. This dose of verapamil did not modify the effect of exercise on metabolic and hemodynamic parameters. In addition, verapamil blocked the activation of NADPH oxidase during early preconditioning. The protective effect of exercise preconditioning on myocardial infarct size is triggered, at least in part, by calcium inflow increase to the cell during exercise and, during the early window, is mediated by NADPH oxidase activation. PMID:25658459

  19. Triptolide Protects Against Ischemic Stroke in Rats.

    PubMed

    Hao, Maolin; Li, Xianghua; Feng, Jianli; Pan, Ning

    2015-08-01

    Inflammatory response plays an important role in the pathogenesis of ischemic stroke and anti-inflammatory agents may provide a choice of treatment. Triptolide is reported to be anti-inflammatory. In this study, we investigated the effects of triptolide on cultured neuronal cell line in vitro and experimental ischemic stroke in vivo. Oxygen-glucose deprivation (OGD) and tumor necrosis factor-? (TNF-?) stimulated SH-SY5Y cells were incubated with triptolide. In vivo, rats were subjected to middle cerebral artery occlusion (MCAO) for 1 h, followed by reperfusion for 23 h. Results of this study showed that triptolide treatment reduced the OGD-induced cytotoxicity and apoptosis and blocked TNF-?-induced activation of NF-?B and p38MAPK in SH-SY5Y cells. Intraperitoneal injection of triptolide showed significant neuroprotective actions in stroke rats. Triptolide attenuated neurological deficit, brain infarct volume, and brain water content, and inhibited activation of NF-?B and p38MAPK. These data show that triptolide protects rats against ischemic cerebral injury via inhibiting NF-?B and p38MAPK signaling pathways. PMID:25687641

  20. Critical care of acute ischemic stroke.

    PubMed

    Bernstein, R A; Hemphill, J C

    2001-11-01

    Advances in neurologic therapeutics and intensive care medicine have expanded the arsenal of treatments available for the critical care of ischemic stroke. Several agents are available for acute reperfusion of the ischemic brain. These include intravenous recombinant tissue-plasminogen activator (rtPA), which is effective in a 3-hour time window, and intra-arterial thrombolytics, which may be effective within 6 hours. In addition, newer agents such as Ancrod and abciximab may be effective within the acute time period. Efforts to prevent secondary brain injury in critically ill patients with stroke often include prevention and reduction of fever, induced hypertension, and mechanical ventilation. Finally, death due to severe brain edema after massive hemispheric infarction can often be prevented with surgical or medical intervention. Unfortunately, there is a critical lack of well-designed clinical studies to guide the clinician in the use of these interventions. In addition, there is concern that some of these interventions may preserve life at the cost of quality of life. This article reviews the evidence behind these approaches to the critical care of ischemic stroke. PMID:11898573

  1. Cerebral autoregulation and acute ischemic stroke.

    PubMed

    Jordan, J Dedrick; Powers, William J

    2012-09-01

    Cerebral autoregulation tightly controls blood flow to the brain by coupling cerebral metabolic demand to cerebral perfusion. In the setting of acute brain injury, such as that caused by ischemic stroke, the continued precise control of cerebral blood flow (CBF) is vital to prevent further injury. Chronic as well as acute elevations in blood pressure are frequently associated with stroke, therefore, understanding the physiological response of the brain to the treatment of hypertension is clinically important. Physiological data obtained in patients with acute ischemic stroke provide no clear evidence that there are alterations in the intrinsic autoregulatory capacity of cerebral blood vessels, except perhaps in infarcted tissue. While it is likely safe to modestly reduce blood pressure by 10-15 mm Hg in most patients with acute ischemic stroke, to date, there are no controlled trial data to indicate that reducing blood pressure is beneficial. There may be subgroups, such as those with persistent large vessel occlusion, large infarcts with edema causing increased intracranial pressure or local mass effect, or chronic hypertension, in which blood pressure reduction may lead to impaired cerebral perfusion in noninfarcted tissue. PMID:22573015

  2. Transglutaminase 2 protects against ischemic stroke

    PubMed Central

    Filiano, AJ; Tucholski, J; Dolan, PJ; Colak, G; Johnson, GVW

    2010-01-01

    Transglutaminase 2 (TG2) is a multifunctional protein that modulates cell survival and death pathways. It is upregulated in numerous ischemic models, and protects primary neurons from oxygen and glucose deprivation. TG2 binds to the hypoxia inducible factor (HIF) 1? and decreases the upregulation of hypoxic-induced proapoptotic genes. To investigate the role of TG2 in ischemic stroke in vivo, we used the murine, permanent middle cerebral artery (MCA) ligation model. TG2 mRNA levels are increased after MCA ligations, and transgenic mice that express human TG2 in neurons had significantly smaller infarct volumes than wild type littermates. Further, TG2 translocates into the nucleus within 2 hours post ligation. Nuclear-localized TG2 is also apparent in human stroke cases. TG2 suppressed the up regulation of the HIF-induced, proapoptotic gene, Noxa. The findings of this study indicate that TG2 plays a role in attenuating ischemic-induced cell death possibly by modulating hypoxic-induced transcriptional processes. PMID:20451610

  3. Preconditioning and postconditioning: underlying mechanisms and clinical application.

    PubMed

    Hausenloy, Derek J; Yellon, Derek M

    2009-06-01

    Coronary heart disease (CHD) is the leading cause of death world-wide. Its major pathophysiological manifestation is acute myocardial ischaemia-reperfusion injury. Innovative treatment strategies for protecting the myocardium against the detrimental effects of this form of injury are required in order to improve clinical outcomes in patients with CHD. In this regard, harnessing the endogenous protection elicited by the heart's ability to 'condition' itself, has recently emerged as a powerful new strategy for limiting myocardial injury, preserving left ventricular systolic function and potentially improving morbidity and mortality in patients with CHD. 'Conditioning' the heart to tolerate the effects of acute ischaemia-reperfusion injury can be initiated through the application of several different mechanical and pharmacological strategies. Inducing brief non-lethal episodes of ischaemia and reperfusion to the heart either prior to, during, or even after an episode of sustained lethal myocardial ischaemia has the capacity to dramatically reduce myocardial injury--a phenomenon termed ischaemic preconditioning (IPC), preconditioning or postconditioning, respectively. Intriguingly, similar levels of cardioprotection can be achieved by applying the brief episodes of non-lethal ischaemia and reperfusion to an organ or tissue remote from the heart, thereby obviating the need to 'condition' the heart directly. This phenomenon has been termed remote ischaemic 'conditioning', and it can offer widespread systemic protection to other organs which are susceptible to acute ischaemia-reperfusion injury such as the brain, liver, intestine or kidney. Furthermore, the identification of the signalling pathways which underlie the effects of 'conditioning', has provided novel targets for pharmacological agents allowing one to recapitulate the benefits of these cardioprotective phenomena--so-termed pharmacological preconditioning and postconditioning. Initial clinical studies, reporting beneficial effects of 'conditioning' the heart to tolerate acute ischaemia-reperfusion injury, have been encouraging. Larger multi-centred randomised studies are now required to determine whether these 'conditioning' strategies are able to impact on clinical outcomes. In this article, we provide an overview of 'conditioning' in all its various forms, describe the underlying mechanisms and review the recent clinical application of this emerging cardioprotective strategy. PMID:19081095

  4. 77 FR 33227 - Assessment Questionnaire-IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-05

    ...DHS-2011-0069] Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT) AGENCY: National Protection and...NPPD), Office of Infrastructure Protection (IP), Sector Outreach and Programs...

  5. 76 FR 81955 - Assessment Questionnaire-IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ...DHS-2011-0069] Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT) AGENCY: National Protection and...NPPD), Office of Infrastructure Protection (IP), Sector Specific Agency Executive...

  6. Eigenmode Analysis of Boundary Conditions for One-Dimensional Preconditioned Euler Equations

    NASA Technical Reports Server (NTRS)

    Darmofal, David L.

    1998-01-01

    An analysis of the effect of local preconditioning on boundary conditions for the subsonic, one-dimensional Euler equations is presented. Decay rates for the eigenmodes of the initial boundary value problem are determined for different boundary conditions. Riemann invariant boundary conditions based on the unpreconditioned Euler equations are shown to be reflective with preconditioning, and, at low Mach numbers, disturbances do not decay. Other boundary conditions are investigated which are non-reflective with preconditioning and numerical results are presented confirming the analysis.

  7. Avaya one-XTM Deskphone Value Edition 1603 IP Telephone

    E-print Network

    Avaya one-XTM Deskphone Value Edition 1603 IP Telephone User Guide 16-601444 Issue 1 July 2007 #12 ..................................................................................................... 5 Introduction to the 1603 IP Telephone .................................................. 7

  8. Avaya one-XTM Deskphone Edition for 9620 IP Telephone

    E-print Network

    Avaya one-XTM Deskphone Edition for 9620 IP Telephone User Guide 16-300699 Issue 3 January 2007 #12 ..................................................................................................... 5 Introduction to the 9620 IP Telephone .................................................. 7

  9. Avaya one-XTM Deskphone Value Edition 1608 IP Telephone

    E-print Network

    Avaya one-XTM Deskphone Value Edition 1608 IP Telephone User Guide 16-601446 Issue 1 July 2007 #12 ..................................................................................................... 5 Introduction to the 1608 IP Telephone .................................................. 7

  10. A frequency dependent preconditioned wavelet method for atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Yudytskiy, Mykhaylo; Helin, Tapio; Ramlau, Ronny

    2013-12-01

    Atmospheric tomography, i.e. the reconstruction of the turbulence in the atmosphere, is a main task for the adaptive optics systems of the next generation telescopes. For extremely large telescopes, such as the European Extremely Large Telescope, this problem becomes overly complex and an efficient algorithm is needed to reduce numerical costs. Recently, a conjugate gradient method based on wavelet parametrization of turbulence layers was introduced [5]. An iterative algorithm can only be numerically efficient when the number of iterations required for a sufficient reconstruction is low. A way to achieve this is to design an efficient preconditioner. In this paper we propose a new frequency-dependent preconditioner for the wavelet method. In the context of a multi conjugate adaptive optics (MCAO) system simulated on the official end-to-end simulation tool OCTOPUS of the European Southern Observatory we demonstrate robustness and speed of the preconditioned algorithm. We show that three iterations are sufficient for a good reconstruction.

  11. Preconditioned Mixed Spectral Element Methods for Elasticity and Stokes Problems

    NASA Technical Reports Server (NTRS)

    Pavarino, Luca F.

    1996-01-01

    Preconditioned iterative methods for the indefinite systems obtained by discretizing the linear elasticity and Stokes problems with mixed spectral elements in three dimensions are introduced and analyzed. The resulting stiffness matrices have the structure of saddle point problems with a penalty term, which is associated with the Poisson ratio for elasticity problems or with stabilization techniques for Stokes problems. The main results of this paper show that the convergence rate of the resulting algorithms is independent of the penalty parameter, the number of spectral elements Nu and mildly dependent on the spectral degree eta via the inf-sup constant. The preconditioners proposed for the whole indefinite system are block-diagonal and block-triangular. Numerical experiments presented in the final section show that these algorithms are a practical and efficient strategy for the iterative solution of the indefinite problems arising from mixed spectral element discretizations of elliptic systems.

  12. Is There A Place For Cerebral Preconditioning In The Clinic?

    PubMed Central

    Keep, Richard F.; Wang, Michael M.; Xiang, Jianming; Hua, Ya; Xi, Guohua

    2010-01-01

    Preconditioning (PC) describes a phenomenon whereby a sub-injury inducing stress can protect against a later injurious stress. Great strides have been made in identifying the mechanisms of PC-induced protection in animal models of brain injury. While these may help elucidate potential therapeutic targets, there are questions over the clinical utility of cerebral PC, primarily because of questions over the need to give the PC stimulus prior to the injury, narrow therapeutic windows and safety. The object of this review is to address the question of whether there may indeed be a clinical use for cerebral PC and to discuss the deficiencies in our knowledge of PC that may hamper such clinical translation. PMID:20563278

  13. Antithrombotic selection and risk factor management in ischemic stroke and transient ischemic attack.

    PubMed

    Katz, Brian S; Flemming, Kelly D

    2014-01-01

    In addition to appropriate antithrombotic therapy, the identification and treatment of modifiable ischemic stroke risk factors can reduce the likelihood of recurrent stroke. Neurosurgeons should be knowledgeable of the specific risk factors and general recommendations for ischemic stroke, as they may play a significant role in the management options for patients with intracranial and extracranial atherosclerotic disease. The authors of this article review the indications for and selection of antithrombotics in patients with cerebral ischemia. In addition, the identification and secondary prevention of select risk factors are discussed. PMID:24380476

  14. Artificial muscle technology applied towards treating ischemic mitral regurgitation caused by left ventricular remodeling

    E-print Network

    Sabourin, Nicaulas A. (Nicaulas Alexandre), 1978-

    2004-01-01

    Ischemic Mitral Regurgitation (MR) affects a large portion of patients suffering from ischemic heart disease. Significant MR develops in one quarter to one third of patients who suffer from ischemic heart disease and doubles ...

  15. AT&T IP Toll-Free is an inbound Voice over IP (VoIP) service providing delivery of toll-free

    E-print Network

    Fisher, Kathleen

    AT&T IP Toll-Free is an inbound Voice over IP (VoIP) service providing delivery of toll-free calls directly to your locations. AT&T IP Toll-Free Service is a voice service similar to traditional toll-free service but data traffic can travel with it over a single IP network utilizing AT&T's common shared

  16. Iterated preconditioned LSQR method for inverse problems on unstructured grids

    NASA Astrophysics Data System (ADS)

    Arridge, S. R.; Betcke, M. M.; Harhanen, L.

    2014-06-01

    This article presents a method for solving large-scale linear inverse imaging problems regularized with a nonlinear, edge-preserving penalty term such as total variation or the Perona-Malik technique. Our method is aimed at problems defined on unstructured meshes, where such regularizers naturally arise in unfactorized form as a stiffness matrix of an anisotropic diffusion operator and factorization is prohibitively expensive. In the proposed scheme, the nonlinearity is handled with lagged diffusivity fixed point iteration, which involves solving a large-scale linear least squares problem in each iteration. Because the convergence of Krylov methods for problems with discontinuities is notoriously slow, we propose to accelerate it by means of priorconditioning (Bayesian preconditioning). priorconditioning is a technique that, through transformation to the standard form, embeds the information contained in the prior (Bayesian interpretation of a regularizer) directly into the forward operator and thence into the solution space. We derive a factorization-free preconditioned LSQR algorithm (MLSQR), allowing implicit application of the preconditioner through efficient schemes such as multigrid. The resulting method is also matrix-free i.e. the forward map can be defined through its action on a vector. We illustrate the performance of the method on two numerical examples. Simple 1D-deblurring problem serves to visualize the discussion throughout the paper. The effectiveness of the proposed numerical scheme is demonstrated on a three-dimensional problem in fluorescence diffuse optical tomography with total variation regularization derived algebraic multigrid preconditioner, which is the type of large scale, unstructured mesh problem, requiring matrix-free and factorization-free approaches that motivated the work here.

  17. IPS guidestar selection for stellar mode (ASTRO)

    NASA Technical Reports Server (NTRS)

    Mullins, Larry; Wooten, Lewis

    1988-01-01

    This report describes how guide stars are selected for the Optical Sensor Package (OSP) for the Instrument Pointing System (IPS) when it is operating in the stellar mode on the ASTRO missions. It also describes how the objective loads are written and how the various roll angles are related; i.e., the celestial roll or position angle, the objective load roll angles, and the IPS gimbal angles. There is a brief description of how the IPS operates and its various modes of operation; i.e., IDOP, IDIN, and OSPCAL.

  18. First IPS Radio Sources Detected By MEXART

    NASA Astrophysics Data System (ADS)

    Mejia-Ambriz, J.; Gonzalez-Esparza, A.; Carrillo-Vargas, A.; Villanueva-Hernandez, P.; Aguilar-Rodriguez, E.; Andrade-Mascote, E.; Vazquez-Hernandez, S.; Sierra-Figueredo, P.; Ananthakrishnan, S.; Manoharan, P.

    2008-12-01

    We present a first study of strong radio sources that are known to exhibit interplanetary scintillations (IPS) detected by the Mexican Array Radio Telescope (MEXART). These observations were made using one quarter of the total antenna (16 rows of 64 dipoles each) and a Butler Matrix (BM) of 16X16 ports. The BM displays 16 beams at different declinations (from -48 to +88 degrees). We report the directionality and efficiency of the beams. These first observations of radio IPS sources and the calibration of the BM is the first step to initiate MEXART IPS maps in the near future.

  19. Hybrid preconditioning for iterative diagonalization of ill-conditioned generalized eigenvalue problems in electronic structure calculations

    SciTech Connect

    Cai, Yunfeng, E-mail: yfcai@math.pku.edu.cn [LMAM and School of Mathematical Sciences, Peking University, Beijing 100871 (China) [LMAM and School of Mathematical Sciences, Peking University, Beijing 100871 (China); Department of Computer Science, University of California, Davis 95616 (United States); Bai, Zhaojun, E-mail: bai@cs.ucdavis.edu [Department of Computer Science and Department of Mathematics, University of California, Davis 95616 (United States)] [Department of Computer Science and Department of Mathematics, University of California, Davis 95616 (United States); Pask, John E., E-mail: pask1@llnl.gov [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Sukumar, N., E-mail: nsukumar@ucdavis.edu [Department of Civil and Environmental Engineering, University of California, Davis 95616 (United States)

    2013-12-15

    The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for ab initio electronic structure calculations. We propose a hybrid preconditioning scheme to effectively combine global and locally accelerated preconditioners for rapid iterative diagonalization of such eigenvalue problems. In partition-of-unity finite-element (PUFE) pseudopotential density-functional calculations, employing a nonorthogonal basis, we show that the hybrid preconditioned block steepest descent method is a cost-effective eigensolver, outperforming current state-of-the-art global preconditioning schemes, and comparably efficient for the ill-conditioned generalized eigenvalue problems produced by PUFE as the locally optimal block preconditioned conjugate-gradient method for the well-conditioned standard eigenvalue problems produced by planewave methods.

  20. Preconditioning for Numerical Simulation of Low Mach Number Three-Dimensional Viscous Turbomachinery Flows

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.; Chima, Rodrick V.; Turkel, Eli

    1997-01-01

    A preconditioning scheme has been implemented into a three-dimensional viscous computational fluid dynamics code for turbomachine blade rows. The preconditioning allows the code, originally developed for simulating compressible flow fields, to be applied to nearly-incompressible, low Mach number flows. A brief description is given of the compressible Navier-Stokes equations for a rotating coordinate system, along with the preconditioning method employed. Details about the conservative formulation of artificial dissipation are provided, and different artificial dissipation schemes are discussed and compared. The preconditioned code was applied to a well-documented case involving the NASA large low-speed centrifugal compressor for which detailed experimental data are available for comparison. Performance and flow field data are compared for the near-design operating point of the compressor, with generally good agreement between computation and experiment. Further, significant differences between computational results for the different numerical implementations, revealing different levels of solution accuracy, are discussed.

  1. Predictors of Vascular Events after Ischemic Stroke: The China Ischemic Stroke Registry Study

    Microsoft Academic Search

    Ding Ding; Chuan-zhen Lu; Jian-hui Fu; Zhen Hong

    2010-01-01

    Background\\/Aims: To measure the risk of vascular event occurrence among postischemic stroke patients in mainland China. Methods: In this multicenter prospective stroke registry study, we enrolled 1,951 patients diagnosed with acute ischemic stroke. Demographic data, prestroke risk factors, severity of neurological deficits and disability graded on the National Institutes of Health Stroke Scale (NIHSS), and modified Rankin Scale scores of

  2. Ischemic and non-ischemic acute kidney injury cause hepatic damage

    Microsoft Academic Search

    Fereshteh Golab; Mehri Kadkhodaee; Maryam Zahmatkesh; Mehdi Hedayati; Hossein Arab; Rebecca Schuster; Kamyar Zahedi; Alex B Lentsch; Manoocher Soleimani

    2009-01-01

    Recent studies have documented that remote organs are affected by ischemic injury to the kidney. Here we studied whether the liver also suffers damage during induction of renal ischemia–reperfusion in rats and compared this to bilateral nephrectomy. Hepatic levels of tumor necrosis factor-? increased significantly after 6 and 24 h of renal ischemia or nephrectomy. Malondialdehyde, an index of lipid

  3. WATERMARKING FPGA BITSTREAM FOR IP Presented to

    E-print Network

    Lee, Hsien-Hsin "Sean"

    WATERMARKING FPGA BITSTREAM FOR IP PROTECTION A Thesis Presented to The Academic Faculty by Pratik of Electrical and Computer Engineering Georgia Institute of Technology August 2008 #12;WATERMARKING FPGA GATE ARRAY . . . . . . . . . . . . . . . 5 2.1 FPGA Architecture

  4. IP routing lookup: hardware and software approach 

    E-print Network

    Chakaravarthy, Ravikumar V.

    2005-08-29

    The work presented in this thesis is motivated by the dual goal of developing a scalable and efficient approach for IP lookup using both hardware and software approach. The work involved designing algorithms and techniques ...

  5. IP SAN - From iSCSI to IP-Addressable Ethernet Disks

    Microsoft Academic Search

    Peter Wang; Robert E. Gilligan; Henry Green; Jeff Raubitschek

    2003-01-01

    The initial iSCSI products provide a means to connect FC SAN islands across IP networks. This paper describes the implementation of an IP-SAN where the disk subsystem is a virtual array of individually Ethernet attached IP-addressable disks. By replacing the conventional peripheral bus and loop interconnects with a switched Gigabit Ethernet network, the virtual disk array scales continually and dynamically

  6. IGN2IP : Internetworking Intelligent Gadget Network based on 802.15.4 with IP Network

    Microsoft Academic Search

    KwangHee Lee; JongHo Won; ChangSeok Bae

    2008-01-01

    In order to provide various personalized services, multiple intelligent gadgets that we call the intelligent gadget network(IGN) can cooperate together through the wireless network using the 802.15.4 technology known as ZigBee. For personalized services, IGN should be interoperable with the IP network which provides well-defined and useful services. In this paper, we propose IGN2IP that interconnect IGN with the IP

  7. Preconditioned domain decomposition scheme for three-dimensional aerodynamic sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Eleshaky, Mohammed E.; Baysal, Oktay

    1993-01-01

    A preconditioned domain decomposition scheme is introduced for the solution of the 3D aerodynamic sensitivity equation. This scheme uses the iterative GMRES procedure to solve the effective sensitivity equation of the boundary-interface cells in the sensitivity analysis domain-decomposition scheme. Excluding the dense matrices and the effect of cross terms between boundary-interfaces is found to produce an efficient preconditioning matrix.

  8. Rapid communication Genetic depletion of cardiac myocyte STAT3 abolishes classical preconditioning

    Microsoft Academic Search

    Robert M. Smith; Naushaad Suleman; Lydia Lacerda; Lionel H. Opie; Shizuo Akira; Kenneth R. Chien; Michael N. Sack

    Objective: To evaluate the functional requirement of signal transducer and activator of transcription-3 (STAT-3) in cardiac myocyte tolerance to ischemia (I) and in classical preconditioning. Methods: Cardiac myocyte STAT-3 was depleted in mice using Cre-lox p technology. Isolated cardiomyocytes from wild-type (WT) and STAT-3-deficient mice were evaluated for viability following simulated ischemia (SI; 26 h). Cardiomyocytes were then preconditioned by

  9. That Which Does Not Kill You Makes You Stronger: A Molecular Mechanism for Preconditioning

    NSDL National Science Digital Library

    Jonathan E. McDunn (Washington University School of Medicine; Cellular Injury and Adaptation Laboratory, Departments of Surgery and Genetics REV)

    2005-07-05

    Preconditioning by sublethal stress can protect a cell from subsequent injury and apoptosis through a mechanism that has been unclear. Many such stresses stimulate the formation of stress granules: transient cytoplasmic foci that contain heat shock protein as well as translationally stalled mRNA and various mRNA-binding proteins. Recent research suggests that sequestration in stress granules of TRAF2, an adaptor protein that is required for tumor necrosis factor receptor 1 signaling, may underlie preconditioning by sublethal stresses.

  10. Anti-inflammatory effects of limb ischaemic preconditioning are mediated by sensory nerve activation in rats

    Microsoft Academic Search

    Petra Hartmann; Renáta Varga; Zsuzsanna Zobolyák; Júlia Héger; Blanka Cs?sz; István Németh; Zsolt Rázga; Csaba Vízler; Dénes Garab; Péter Sántha; Gábor Jancsó; Mihály Boros; Andrea Szabó

    2011-01-01

    We have shown that ischaemic preconditioning ameliorates both the local periosteal and the systemic leukocyte activation evoked\\u000a by limb ischaemia–reperfusion. We hypothesized that the activation of chemosensitive afferent nerves by transient ischaemia\\u000a contributes to the protective mechanisms of ischaemic preconditioning via a calcitonin gene-related peptide (CGRP)-dependent\\u000a mechanism. In Sprague–Dawley rats, 60-min complete limb ischaemia was followed by 180 min of reperfusion.

  11. Effect of cyclic preconditioning on the tensile properties of human quadriceps tendons and patellar ligaments

    Microsoft Academic Search

    L. Schatzmann; P. Brunner; H. U. Stäubli

    1998-01-01

    Preconditioning of soft tissues has become a common procedure in tensile testing to assess the history dependence of these viscoelastic materials. To our knowledge, this is the first study comparing tensile properties of soft tissues before and after cyclic preconditioning with high loads. Sixteen quadriceps tendon-bone (QT-B) complexes and 16 patellar ligament-bone (PL-B) complexes from a young population (mean age

  12. Development of Roe-type scheme for all-speed flows based on preconditioning method

    Microsoft Academic Search

    Xue-song Li; Chun-wei Gu; Jian-zhong Xu

    2009-01-01

    The problems of mixed low-speed\\/high-speed flows are not solved properly with existing compressible method. Based on preconditioning technology, a new scheme, All-Speed-Roe scheme, is proposed. Compared with Roe scheme, it decreases the effect of acoustic speed in its numerical dissipation when Mach numbers decrease. Compared with traditional preconditioned Roe scheme, it overcomes the limit of being cut-off by the global

  13. Thrombin Preconditioning Reduces Iron-Induced Brain Swelling and Brain Atrophy

    Microsoft Academic Search

    Shuijiang Song; Haitao Hu; Ya Hua; Jianan Wang; Guohua Xi

    \\u000a Cerebral preconditioning with a low dose of thrombin attenuates brain edema induced by intracerebral hemorrhage (ICH), a large\\u000a dose of thrombin or iron. This study examined whether or not thrombin preconditioning (TPC) reduces neuronal death and brain\\u000a atrophy caused by iron. The right hippocampus of rats was pretreated with or without thrombin, and iron was then injected\\u000a into the same

  14. Intrusion detection in voice over IP environments

    Microsoft Academic Search

    Yu-sung Wu; Vinita Apte; Saurabh Bagchi; Sachin Garg; Navjot Singh

    2009-01-01

    In this article, we present the design of an intrusion detection system for voice over IP (VoIP) networks. The first part\\u000a of our work consists of a simple single- component intrusion detection system called Scidive. In the second part, we extend the design of Scidive and build a distributed\\u000a and\\u000a correlation-based intrusion detection system called Space\\u000a Dive. We create several

  15. IP Address Autoconfiguration for Ad Hoc Networks

    Microsoft Academic Search

    Charles E. Perkins; Elizabeth M. Royer; Samir R. Das

    2000-01-01

    If a node lacks an IP address, it cannot yet participate in ad hocnetworks as currently designed, because the connectivity in an ad hocnetwork is typically determined by mechanisms that depend upon usingPerkins Expires 10 January 2001 [Page i]Internet Draft Ad Hoc Address Autoconfiguration 10 July 2000the IP address as the identifier for the nodes in the ad hoc network.In

  16. Ischemic Neuropathy Associated with Livedoid Vasculitis

    PubMed Central

    Kim, Jee-Eun; Park, Su-Yeon; Sinn, Dong In; Kim, Sung-Min; Hong, Yoon-Ho; Park, Kyung Seok; Lee, Kwang-Woo

    2011-01-01

    Background Livedoid vasculitis is a chronic dermatological problem with an unclear etiology. Clinical findings are petechiae with painful ulcers in both lower extremities, which heal to become hyperpigmented and porcelain-white satellite lesions. There are only a few reported cases of livedoid vasculitis presenting in combination with peripheral neuropathy. Case Report We report the first case of a Korean patient presenting with mononeuritis multiplex combined with livedoid vasculitis, which was confirmed by electrophysiological and pathological studies. Conclusions Our report supports the possible vaso-occlusive etiology of livedoid vasculitis in multifocal ischemic neuropathy. PMID:22259622

  17. Convergence Acceleration of the Navier-Stokes Equations Through Time-Derivative Preconditioning

    NASA Technical Reports Server (NTRS)

    Merkle, Charles L.; Venkateswaran, Sankaran; Deshpande, Manish

    1996-01-01

    Chorin's method of artificial compressibility is extended to both compressible and incompressible fluids by using physical arguments to define artificial fluid properties that make up a local preconditioning matrix. In particular, perturbation expansions are used to provide appropriate temporal derivatives for the equations of motion at both low speeds and low Reynolds numbers. These limiting forms are then combined into a single function that smoothly merges into the physical time derivatives at high speeds so that the equations are left unchanged at transonic, high Reynolds number conditions. The effectiveness of the resulting preconditioning procedures for the Navier-Stokes equations is demonstrated for a wide speed and Reynolds number ranges by means of stability results and computational solutions. Nevertheless, the preconditioned equations sometimes fail to provide a solution for applications for which the non-preconditioned equations converge. Often this is because the reduced dissipation in the preconditioned equations results in an unsteady solution while the more dissipative non-preconditioned equations result in a steady state. Problems of this type represent a computational challenge; it is important to distinguish between non-convergence of algorithms, and the non-existence of steady state solutions.

  18. Independent Walking After Neonatal Arterial Ischemic Stroke and Sinovenous Thrombosis

    Microsoft Academic Search

    Meredith R. Golomb; Gabrielle A. deVeber; Daune L. MacGregor; Trish Domi; Hilary Whyte; Derek Stephens; Paul T. Dick

    2003-01-01

    Few studies have examined walking after neonatal arterial ischemic stroke and sinovenous thrombosis. We looked at the development of walking in a retrospective and consecutive cohort study of 88 term and near-term neonates. We used Kaplan-Meier survival curves and Cox proportional hazards models to assess (1) sex, (2) stroke type (arterial ischemic stroke or sinovenous thrombosis), (3) number of cerebral

  19. Ischemic jejunitis caused by primary small bowel volvulus.

    PubMed

    Verbeke, J; Ponette, E; Baert, A L

    1997-08-01

    A case of ischemic jejunitis caused by primary small bowel volvulus is presented. The radiological signs of ischemia persisted after detorsion. Contrast examinations of the small intestine demonstrated severe jejunitis with ulcerations, segmental narrowing and fistulas. This last sign is a rather uncommon event in ischemic disorders. The radiological signs of acute ischemia of the small intestine are discussed. PMID:9351305

  20. Racial Differences in Thoracic Aorta Atherosclerosis Among Ischemic Stroke Patients

    Microsoft Academic Search

    Vishal Gupta; Navin C. Nanda; Dilek Yesilbursa; Wen Ying Huang; Vijaya Gupta; Qing Li; Camilo R. Gomez

    Background and Purpose—Atherosclerosis of the thoracic aorta is an independent risk factor for stroke. There is little information on the impact of race in the prevalence of thoracic aorta atherosclerotic plaques among ischemic stroke patients. This study was an attempt to objectively assess the prevalence, thickness, and burden of thoracic aorta atherosclerotic plaques in a large population of ischemic stroke

  1. Changes of resting cerebral activities in subacute ischemic stroke patients.

    PubMed

    Wu, Ping; Zeng, Fang; Li, Yong-Xin; Yu, Bai-Li; Qiu, Li-Hua; Qin, Wei; Li, Ji; Zhou, Yu-Mei; Liang, Fan-Rong

    2015-05-01

    This study aimed to detect the difference in resting cerebral activities between ischemic stroke patients and healthy participants, define the abnormal site, and provide new evidence for pathological mechanisms, clinical diagnosis, prognosis prediction and efficacy evaluation of ischemic stroke. At present, the majority of functional magnetic resonance imaging studies focus on the motor dysfunction and the acute stage of ischemic stroke. This study recruited 15 right-handed ischemic stroke patients at subacute stage (15 days to 11.5 weeks) and 15 age-matched healthy participants. A resting-state functional magnetic resonance imaging scan was performed on each subject to detect cerebral activity. Regional homogeneity analysis was used to investigate the difference in cerebral activities between ischemic stroke patients and healthy participants. The results showed that the ischemic stroke patients had lower regional homogeneity in anterior cingulate and left cerebrum and higher regional homogeneity in cerebellum, left precuneus and left frontal lobe, compared with healthy participants. The experimental findings demonstrate that the areas in which regional homogeneity was different between ischemic stroke patients and healthy participants are in the cerebellum, left precuneus, left triangle inferior frontal gyrus, left inferior temporal gyrus and anterior cingulate. These locations, related to the motor, sensory and emotion areas, are likely potential targets for the neural regeneration of subacute ischemic stroke patients. PMID:26109950

  2. Renal Function Predicts Survival in Patients with Acute Ischemic Stroke

    Microsoft Academic Search

    Elizabeth Mostofsky; Gregory A. Wellenius; Amit Noheria; Emily B. Levitan; Mary R. Burger; Gottfried Schlaug; Murray A. Mittleman

    2009-01-01

    Background: Among patients with acute ischemic stroke, impaired kidney function has been shown to increase the mortality risk, but the shape of this relationship has not been evaluated in detail. Methods: We estimated the glomerular filtration rate (eGFR) at the time of hospitalization in 1,175 consecutive patients hospitalized with acute ischemic stroke at the Beth Israel Deaconess Medical Center and

  3. Study on frequency and predictors of dementia after ischemic stroke

    Microsoft Academic Search

    David H. D. Zhou; John Y. J. Wang; Jingcheng Li; Juan Deng; Changyue Gao; Man’e Chen

    2004-01-01

    Objective: We studied a large hospitalized cohort of patients aged 55 years and over with acute ischemic stroke to identify the frequency and predictors of poststroke dementia. Methods: A total of 434 consecutive patients with ischemic stroke were enrolled in this study. During admission, the demographic data, vascular risk factors, stroke features, and neurological status information were collected. All subjects

  4. Cyclic RGD peptides ameliorate ischemic acute renal failure in rats

    Microsoft Academic Search

    Eisei Noiri; James Gailit; Dipak Sheth; Harold Magazine; Marion Gurrath; Gerhard Muller; Horst Kessler; Michael S Goligorsky

    1994-01-01

    Cyclic RGD peptides ameliorate ischemic acute renal failure in rats. Renal tubular obstruction is an important contributor to the pathophysiology of acute renal failure. Based on the previous findings of the role played by arginine-glycine-aspartic acid (RGD) recognizing integrins in tubular obstruction, this study examined the effect of RGD peptides on the course of ischemic acute renal failure in rats.

  5. Changes of resting cerebral activities in subacute ischemic stroke patients

    PubMed Central

    Wu, Ping; Zeng, Fang; Li, Yong-xin; Yu, Bai-li; Qiu, Li-hua; Qin, Wei; Li, Ji; Zhou, Yu-mei; Liang, Fan-rong

    2015-01-01

    This study aimed to detect the difference in resting cerebral activities between ischemic stroke patients and healthy participants, define the abnormal site, and provide new evidence for pathological mechanisms, clinical diagnosis, prognosis prediction and efficacy evaluation of ischemic stroke. At present, the majority of functional magnetic resonance imaging studies focus on the motor dysfunction and the acute stage of ischemic stroke. This study recruited 15 right-handed ischemic stroke patients at subacute stage (15 days to 11.5 weeks) and 15 age-matched healthy participants. A resting-state functional magnetic resonance imaging scan was performed on each subject to detect cerebral activity. Regional homogeneity analysis was used to investigate the difference in cerebral activities between ischemic stroke patients and healthy participants. The results showed that the ischemic stroke patients had lower regional homogeneity in anterior cingulate and left cerebrum and higher regional homogeneity in cerebellum, left precuneus and left frontal lobe, compared with healthy participants. The experimental findings demonstrate that the areas in which regional homogeneity was different between ischemic stroke patients and healthy participants are in the cerebellum, left precuneus, left triangle inferior frontal gyrus, left inferior temporal gyrus and anterior cingulate. These locations, related to the motor, sensory and emotion areas, are likely potential targets for the neural regeneration of subacute ischemic stroke patients.

  6. Section Notes 5 Review of IP, MDP and Stochastic programming

    E-print Network

    Chen, Yiling

    ;1 Lecture 11: Intro to IP · What is an integer program? An integer program (IP) is an optimization problem be integer. · What is a mixed integer program (MIP)? The same as an IP except it may also contain continuous decision variables. · What is a binary integer program (BIP)? The same as an IP except all variables must

  7. Design methods of multilayer survivability in IP over WDM networks

    Microsoft Academic Search

    Shin'ichi Arakawa; Hideo Miyahara

    2000-01-01

    IP (Internet Protocol) over WDM networks where IP packets are directly carried on the WDM network is expected to offer an infrastructure for the next generation Internet. For IP over WDM networks, a WDM protection mechanism is expected to provide a highly reliable network (i.e., robustness against the link\\/node failures). However, conventional IP also provides a reliability mechanism by its

  8. IP Addressing and Routing in a Local Wireless Network

    Microsoft Academic Search

    Danny Cohen; Jonathan B. Postel; Raphael Rom

    1992-01-01

    IP is the basic protocol in the Internet. The authors explore a variety of possibilities to adapt the wireless environment to that of IP. They describe the requirements and show how these can be accommodated by using the existing IP. At the heart of the problem is the lack of a capability in the current IP routing services to track

  9. VoIP Malware: Attack Tool & Attack Scenarios

    Microsoft Academic Search

    Mohamed Nassar; Radu State; Olivier Festor

    2009-01-01

    With the appearance of new Internet services like Voice over IP and IP television, malwares are in the way to update and extend their targets. In this paper, we discuss the emergence of a new generation of malwares attacking VoIP infrastructures and services. Such malwares constitute a real threat to the currently deployed VoIP architectures without strong security measures in

  10. Towards a global IP anycast service Paper 110, 14 Pages

    E-print Network

    Sirer, Emin Gun

    1 Towards a global IP anycast service Paper 110, 14 Pages Abstract IP anycast, with its innate means of service discovery. The growth of P2P ap- plications presents appealing new uses for IP anycast. Unfor- tunately, IP anycast suffers from serious problems: it is very hard to deploy globally, it scales

  11. Checklist for completing IP components I. Globally-Oriented Coursework

    E-print Network

    Wang, Yuhang

    Checklist for completing IP components I. Globally-Oriented Coursework: Prior to graduation, all IP be taken at GT or while abroad. Students will choose one course from each category from the list of IP _______________________ Grade ________________________ We recommend that students use IP-approved courses to fulfill their major

  12. Immunoprecipitations 1. Use 300-400 g protein per IP

    E-print Network

    Pike, Linda J.

    Immunoprecipitations Protocol: 1. Use 300-400 µg protein per IP 2. Add primary antibody as directed Pansorbin and remove supernatnat. Wash once in IP buffer containing 10 mg/ml BSA. Make up to original suspension volume in RIPA buffer and add to IP's. 6. Incubate IP's with Pansorbin for 30 min on ice. 7. Spin

  13. Crown Jewels and War Chests: All About IPAll About IP

    E-print Network

    Puglisi, Joseph

    Crown Jewels and War Chests: All About IPAll About IP Summer Program on Bioentrepreneurship 2009, Stanford University #12;Two Important Questions 1. Why does IP matter to you? 2. Do you have an IP strategy?y gy 2 #12;What Is Intellectual Property? 33 Licensed from the New Yorker #12;Why IP Is Important Do

  14. IIPP: Integrated IP paging protocol with a power save mechanism

    E-print Network

    IIPP: Integrated IP paging protocol with a power save mechanism Ved P. Kafle Department IP paging protocol with a power save mechanism SUMMARY The advent of advanced mobile/wireless systems an integrated IP paging protocol (IIPP) by integrating the IP-layer paging protocol based on Mobile IPv4

  15. Mobility support in IP: a survey of related protocols

    Microsoft Academic Search

    Debanjan Saha; Amitava Mukherjee; Iti Saha Misra; Mohuya Chakraborty; N. Subhash

    2004-01-01

    This article presents an overview of a set of IP-based mobility protocols — Mobile IP, HAWAII, Cellular IP, Hierarchical MIP, TeleMIP, Dynamic Mobility Agent, and Terminal Independent MIP — that will play an important role in the forthcoming convergence of IP and legacy wireless networks. A comparative analysis with respect to system parameters such as location update, handoff latency and

  16. Challenges to the Internet Protocol (IP)Challenges to the Internet Protocol (IP) Dr Mosa Ali Abu-Rgheff

    E-print Network

    Abu-Rgheff, Mosa Ali

    1 Challenges to the Internet Protocol (IP)Challenges to the Internet Protocol (IP) Dr Mosa Ali Abu-Rgheff Department of Communication Eng. University of Plymouth #12;2 The Internet Protocol (IP)The Internet Protocol (IP) Principles of Network Switching: Circuit-Switching : Provides a dedicated path between source

  17. LINEAR COLLIDER TEST FACILITY: TWISS PARAMETER ANALYSIS AT THE IP/POST-IP LOCATION OF THE ATF2 BEAM LINE *

    E-print Network

    Paris-Sud XI, Université de

    LINEAR COLLIDER TEST FACILITY: TWISS PARAMETER ANALYSIS AT THE IP/POST-IP LOCATION OF THE ATF2 BEAM beam tuning, vertical beam size is usually bigger than 3!m at the IP. Beam waist measurements using to the IP. These measurements are described in this paper for the optics currently used ("x=4cm and "y=1mm

  18. [Neuroimaging of the penumbra in ischemic stroke].

    PubMed

    Maksimova, M Iu; Korobkova, D Z; Krotenkova, M V

    2013-01-01

    Brain ischemia has been recently a central problem in basic and applied studies in angioneurology. The latest investigations that give an insight into a relationship between metabolic changes and cerebral blood flow and make it possible to study ischemia at the molecular level and its changes over time have promoted the accumulation of fundamentally new facts and some reappraisal of existing ideas. Ischemic semishadow or penumbra is one of the most important presently studied phenomena. Detection of penumbra signs suggests that it is expedient to evaluate cerebral blood flow and metabolism when planning treatment (thrombolysis or neuroprotective therapy) and that it is important to predict the severity of ischemic stroke. Positron emission tomography (PET) is the reference method for detecting the penumbra; however, its application is limited in clinical practice. Computed tomography (CT) perfusion and perfusion MRI, a combination of diffusion-weighted and perfusion MRI, single-photon emission CT, and xenon-enhanced CT are most frequently used to evaluate a cerebral ischemia area and its blood flow. However, there are no standardized approaches to quantifying the thresholds for cerebral blood flow or unified algorithms for penumbra verification, which calls for further investigations. PMID:25702445

  19. Women and Ischemic Heart Disease: Evolving Knowledge

    PubMed Central

    Shaw, Leslee J.; Bugiardini, Raffaelle; Merz, C. Noel Bairey

    2009-01-01

    Evolving knowledge regarding sex differences in coronary heart disease (CHD) is emerging. Given the lower burden of obstructive coronary artery disease (CAD) and preserved systolic function in women contrasted by higher rates of myocardial ischemia and near-term mortality compared to men, we propose the term ischemic heart disease (IHD) as appropriate for this discussion specific to women, rather than CAD or CHD. This paradoxical difference where women have lower rates of anatomical CAD but more symptoms, ischemia, and outcomes appear linked to coronary reactivity which includes microvascular dysfunction. Novel risk factors can improve the Framingham risk score, including inflammatory markers and reproductive hormones, as well as noninvasive imaging and functional capacity measurements. Risk for women with obstructive CAD is elevated compared to men, yet women are less likely to receive guideline-indicated therapies. In the setting of non-ST elevation acute myocardial infarction, interventional strategies are equally effective in biomarker positive women and men, while conservative management is indicated for biomarker negative women. For women with evidence of ischemia but no obstructive CAD, anti-anginal and anti-ischemic therapies can improve symptoms, endothelial function, and quality of life; however trials evaluating adverse outcomes are needed. We hypothesize that women experience more adverse outcomes compared to men because obstructive CAD remains the current focus of therapeutic strategies. Continued research is indicated to devise therapeutic regimens to improve symptom burden and reduce risk in women with IHD. PMID:19833255

  20. TD6 : Adressage IP abelaid@loria.fr

    E-print Network

    Belaïd, Abdel

    UE 503 L3 MIAGE TD6 : Adressage IP A. Belaïd abelaid@loria.fr http://www.loria.fr/~abelaid/ Année Universitaire 2011/2012 #12;Adressage IP Objectifs ­ Si l'on veut interconnecter des réseaux, on ne peut pas le identifiés à l'intérieur de ce réseau ­ C'est le principe de l'adressage IP #12;Adressage IP ­ Une adresse IP

  1. Practical Implementations for Securing VoIP Enabled Mobile Devices

    Microsoft Academic Search

    Chan Yeob Yeun; Salman Mohammed Al-Marzouqi

    2009-01-01

    Voice over Internet protocol is the ability of transmitting voice using the Internet protocol. This paper addresses an introduction to VoIP, threats of VoIP and studies previous works of secure VoIP. We also propose practical implementations for securing VoIP by using Java and Android. Finally we give security analysis of our implementation and analyze different protocols involved in making VoIP

  2. IP over P2P: Enabling Self-configuring Virtual IP Networks for Grid Computing

    E-print Network

    Figueiredo, Renato J.

    it is decoupled from the address space of the physical Internet infras- tructure -- IP packets are payloads the heterogeneity of Grid [23] computing environ- ments by breaking software dependences between hosts and users private networks). The IPOP virtual IP address space is routable within the P2P overlay, however

  3. Regulation of IP 3 Receptors by IP 3 and Ca 2+

    NASA Astrophysics Data System (ADS)

    Taylor, Colin W.; Swatton, Jane E.

    Inositol 1,4,5-trisphosphate ( IP 3) receptors are intracellular Ca 2+ channels that mediate release of Ca 2+ from intracellular stores. The channels are oligomeric assemblies of four subunits, each of which has an N-terminal IP 3-binding domain and each of which contributes to formation of the Ca 2+ channel. In mammals, three different genes encode IP 3 receptors subunits and the type 1 receptor (and perhaps the type 2 receptor) is also expressed as splice variants. Further diversity arises from assembly of the receptor in hetero- and homo-tetrameric channels. The subtypes differ in their expression and regulation, but they share the key property of being regulated by both IP3 and cytosolic Ca 2+. All three mammalian IP 3 subtypes, and probably also the IP 3 receptors expressed in invertebrates, are biphasically regulated by cytosolic Ca2+, although the underlying mechanisms appear to differ between subtypes. The interactions between IP 3 and Ca 2+ in controlling IP 3 receptor gating, and the physiological significance of such regulation will be reviewed.

  4. HMGB1 in ischemic and non-ischemic liver after selective warm ischemia/reperfusion in rat.

    PubMed

    Liu, Anding; Dirsch, Olaf; Fang, Haoshu; Sun, Jian; Jin, Hao; Dong, Wei; Dahmen, Uta

    2011-05-01

    High mobility group box 1 (HMGB1) acts as an early mediator in inflammation and organ injury. Ischemia reperfusion (I/R) injury induces HMGB1 translocation and expression in ischemic areas. However, it is unknown whether selective warm liver I/R injury also induces the expression of HMGB1 in non-ischemic lobes. The present study aimed to test the hypothesis that selective liver I/R injury also causes HMGB1 translocation and up-regulates its expression in non-ischemic liver areas. In the present study, selective I/R injury was induced by clamping the median and left lateral liver lobes for 90 min followed by 0.5, 6 and 24 h reperfusion. We used male inbred Lewis rats; six animals for each point in time and six animals for the normal control group. Selective hepatic I/R injury induced morphological changes not only in ischemic lobes but also in non-ischemic lobes. HMGB1 translocation and expression was increased in a time-dependent manner in the ischemic lobes, and increased in with delayed onset in the non-ischemic lobes. Serum HMGB1 levels were increased after reperfusion. Furthermore, liver I/R injury up-regulated the expression of HMGB1 receptors (Toll-like receptor 4 and receptor for advanced glycation end products and pro-inflammatory cytokines (Tumor necrosis factor-alpha and interleukin-6) in both ischemic lobes, however, the up-regulation of these cytokines was more prominent in the ischemic lobes. In conclusion, selective warm I/R induces a substantial "sympathetic/bystander" effect on the non-ischemic lobes in terms of HMGB1 translocation and local cytokine production. PMID:21431875

  5. Isoflurane Preconditioning Confers Cardioprotection by Activation of ALDH2

    PubMed Central

    Lang, Xiao-E; Wang, Xiong; Zhang, Ke-Rang; Lv, Ji-Yuan; Jin, Jian-Hua; Li, Qing-Shan

    2013-01-01

    The volatile anesthetic, isoflurane, protects the heart from ischemia/reperfusion (I/R) injury. Aldehyde dehydrogenase 2 (ALDH2) is thought to be an endogenous mechanism against ischemia-reperfusion injury possibly through detoxification of toxic aldehydes. We investigated whether cardioprotection by isoflurane depends on activation of ALDH2.Anesthetized rats underwent 40 min of coronary artery occlusion followed by 120 min of reperfusion and were randomly assigned to the following groups: untreated controls, isoflurane preconditioning with and without an ALDH2 inhibitor, the direct activator of ALDH2 or a protein kinase C (PKC?) inhibitor. Pretreatment with isoflurane prior to ischemia reduced LDH and CK-MB levels and infarct size, while it increased phosphorylation of ALDH2, which could be blocked by the ALDH2 inhibitor, cyanamide. Isolated neonatal cardiomyocytes were treated with hypoxia followed by reoxygenation. Hypoxia/reoxygenation (H/R) increased cardiomyocyte apoptosis and injury which were attenuated by isoflurane and forced the activation of ALDH2. In contrast, the effect of isoflurane-induced protection was almost abolished by knockdown of ALDH2. Activation of ALDH2 and cardioprotection by isoflurane were substantially blocked by the PKC? inhibitor. Activation of ALDH2 by mitochondrial PKC? plays an important role in the cardioprotection of isoflurane in myocardium I/R injury. PMID:23468836

  6. Preconditioning of the Magnetosphere by Calms before the Storm

    NASA Astrophysics Data System (ADS)

    Borovsky, J. E.; Lavraud, B.; Denton, M. H.; Steinberg, J. T.

    2006-12-01

    Intervals of extreme geomagnetic calm occur just prior to 66% of all recurring high-speed-stream-driven storms and just prior to 38% of CME-driven storms. An interval of calm prior to the onset of a storm can precondition the magnetosphere, resulting in a change in the nature of the storm. We will focus on changes in the storms caused by the build up of a large plasmasphere and the build up of cool dense plasma sheet (CDPS) plasma in the magnetosphere. We argue that the built-up plasmasphere during the calm and the resulting plasmaspheric drainage plume during the storm leads to (1) mass loading of the dayside neutral line causing a reduction in solar-wind/magnetosphere coupling during the storm, (2) enhanced decay of the number density of relativistic electrons in the outer radiation belt prior to the storm, (3) a dumping of the outer electron radiation belt by the formation of a clumpy plasmaspheric drainage plume in the early phase of the storm, and (4) mass loading of convection in the inner magnetosphere. We argue that the build up of CDPS plasma in the magnetosphere during a calm provides a more efficient fuel for the production of ring current during the early phase of the storm.

  7. Positive Indian Ocean Dipole events precondition southeast Australia bushfires

    NASA Astrophysics Data System (ADS)

    Cai, W.; Cowan, T.; Raupach, M.

    2009-10-01

    The devastating “Black Saturday” bushfire inferno in the southeast Australian state of Victoria in early February 2009 and the “Ash Wednesday” bushfires in February 1983 were both preceded by a positive Indian Ocean Dipole (pIOD) event. Is there a systematic pIOD linkage beyond these two natural disasters? We show that out of 21 significant bushfires seasons since 1950, 11 were preceded by a pIOD. During Victoria's wet season, particularly spring, a pIOD contributes to lower rainfall and higher temperatures exacerbating the dry conditions and increasing the fuel load leading into summer. Consequently, pIODs are effective in preconditioning Victoria for bushfires, more so than El Niño events, as seen in the impact on soil moisture on interannual time scales and in multi-decadal changes since the 1950s. Given that the recent increase in pIOD occurrences is consistent with what is expected from global warming, an increased bushfire risk in the future is likely across southeast Australia.

  8. Preconditioning diabetic mesenchymal stem cells with myogenic medium increases their ability to repair diabetic heart

    PubMed Central

    2013-01-01

    Introduction Mesenchymal stem cells (MSCs) have the potential for treatment of diabetic cardiomyopathy; however, the repair capability of MSCs declines with age and disease. MSCs from diabetic animals exhibit impaired survival, proliferation, and differentiation and therefore require a strategy to improve their function. The aim of the study was to develop a preconditioning strategy to augment the ability of MSCs from diabetes patients to repair the diabetic heart. Methods Diabetes was induced in C57BL/6 mice (6 to 8 weeks) with streptozotocin injections (55 mg/kg) for 5 consecutive days. MSCs isolated from diabetic animals were preconditioned with medium from cardiomyocytes exposed to oxidative stress and high glucose (HG/H-CCM). Results Gene expression of VEGF, ANG-1, GATA-4, NKx2.5 MEF2c, PCNA, and eNOS was upregulated after preconditioning with HG/H-CCM, as evidenced by reverse transcriptase/polymerase chain reaction (RT-PCR). Concurrently, increased AKT phosphorylation, proliferation, angiogenic ability, and reduced levels of apoptosis were observed in HG/H-CCM-preconditioned diabetic MSCs compared with nontreated controls. HG/H-CCM-preconditioned diabetic-mouse-derived MSCs (dmMSCs) were transplanted in diabetic animals and demonstrated increased homing concomitant with augmented heart function. Gene expression of angiogenic and cardiac markers was significantly upregulated in conjunction with paracrine factors (IGF-1, HGF, SDF-1, FGF-2) and, in addition, reduced fibrosis, apoptosis, and increased angiogenesis was observed in diabetic hearts 4 weeks after transplantation of preconditioned dmMSCs compared with hearts with nontreated diabetic MSCs. Conclusions Preconditioning with HG/H-CCM enhances survival, proliferation, and the angiogenic ability of dmMSCs, augmenting their ability to improve function in a diabetic heart. PMID:23706645

  9. Glycine transporters type 1 inhibitor promotes brain preconditioning against NMDA-induced excitotoxicity.

    PubMed

    Pinto, Mauro Cunha Xavier; Lima, Isabel Vieira de Assis; da Costa, Flávia Lage Pessoa; Rosa, Daniela Valadão; Mendes-Goulart, Vânia Aparecida; Resende, Rodrigo Ribeiro; Romano-Silva, Marco Aurélio; de Oliveira, Antônio Carlos Pinheiro; Gomez, Marcus Vinícius; Gomez, Renato Santiago

    2015-02-01

    Brain preconditioning is a protective mechanism, which can be activated by sub-lethal stimulation of the NMDA receptors (NMDAR) and be used to achieve neuroprotection against stroke and neurodegenerative diseases models. Inhibitors of glycine transporters type 1 modulate glutamatergic neurotransmission through NMDAR, suggesting an alternative therapeutic strategy of brain preconditioning. The aim of this work was to evaluate the effects of brain preconditioning induced by NFPS, a GlyT1 inhibitor, against NMDA-induced excitotoxicity in mice hippocampus, as well as to study its neurochemical mechanisms. C57BL/6 mice (male, 10-weeks-old) were preconditioned by intraperitoneal injection of NFPS at doses of 1.25, 2.5 or 5.0 mg/kg, 24 h before intrahippocampal injection of NMDA. Neuronal death was evaluated by fluoro jade C staining and neurochemical parameters were evaluated by gas chromatography-mass spectrometry, scintillation spectrometry and western blot. We observed that NFPS preconditioning reduced neuronal death in CA1 region of hippocampus submitted to NMDA-induced excitotoxicity. The amino acids (glycine and glutamate) uptake and content were increased in hippocampus of animals treated with NFPS 5.0 mg/kg, which were associated to an increased expression of type-2 glycine transporter (GlyT2) and glutamate transporters (EAAT1, EAAT2 and EAAT3). The expression of GlyT1 was reduced in animals treated with NFPS. Interestingly, the preconditioning reduced expression of GluN2B subunits of NMDAR, whereas did not change the expression of GluN1 or GluN2A in all tested doses. Our study suggests that NFPS preconditioning induces resistance against excitotoxicity, which is associated with neurochemical changes and reduction of GluN2B-containing NMDAR expression. PMID:25312280

  10. Lipopolysaccharide preconditioning facilitates M2 activation of resident microglia after spinal cord injury.

    PubMed

    Hayakawa, Kentaro; Okazaki, Rentaro; Morioka, Kazuhito; Nakamura, Kozo; Tanaka, Sakae; Ogata, Toru

    2014-12-01

    The inflammatory response following spinal cord injury (SCI) has both harmful and beneficial effects; however, it can be modulated for therapeutic benefit. Endotoxin/lipopolysaccharide (LPS) preconditioning, a well-established method for modifying the immune reaction, has been shown to attenuate damage induced by stroke and brain trauma in rodent models. Although such effects likely are conveyed by tissue-repairing functions of the inflammatory response, the mechanisms that control the effects have not yet been elucidated. The present study preconditioned C57BL6/J mice with 0.05 mg/kg of LPS 48 hr before inducing contusion SCI to investigate the effect of LPS preconditioning on the activation of macrophages/microglia. We found that LPS preconditioning promotes the polarization of M1/M2 macrophages/microglia toward an M2 phenotype in the injured spinal cord on quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical analyses. Flow cytometric analyses reveal that LPS preconditioning facilitates M2 activation in resident microglia but not in infiltrating macrophages. Augmented M2 activation was accompanied by vascularization around the injured lesion, resulting in improvement in both tissue reorganization and functional recovery. Furthermore, we found that M2 activation induced by LPS preconditioning is regulated by interleukin-10 gene expression, which was preceded by the transcriptional activation of interferon regulatory factor (IRF)-3, as demonstrated by Western blotting and an IRF-3 binding assay. Altogether, our findings demonstrate that LPS preconditioning has a therapeutic effect on SCI through the modulation of M1/M2 polarization of resident microglia. The present study suggests that controlling M1/M2 polarization through endotoxin signal transduction could become a promising therapeutic strategy for various central nervous system diseases. © 2014 Wiley Periodicals, Inc. PMID:25044014

  11. Mitral valve function following ischemic cardiomyopathy: a biomechanical perspective

    PubMed Central

    Rim, Yonghoon; McPherson, David D.; Kim, Hyunggun

    2014-01-01

    Ischemic mitral valve (MV) is a common complication of pathologic remodeling of the left ventricle due to acute and chronic coronary artery diseases. It frequently represents the pathologic consequences of increased tethering forces and reduced coaptation of the MV leaflets. Ischemic MV function has been investigated from a biomechanical perspective using finite element-based computational MV evaluation techniques. A virtual 3D MV model was created utilizing 3D echocardiographic data in a patient with normal MV. Two types of ischemic MVs containing asymmetric medial-dominant or symmetric leaflet tenting were modeled by altering the configuration of the normal papillary muscle (PM) locations. Computational simulations of MV function were performed using dynamic finite element methods, and biomechanical information across the MV apparatus was evaluated. The ischemic MV with medial-dominant leaflet tenting demonstrated distinct large stress distributions in the posteromedial commissural region due to the medial PM displacement toward the apical-medial direction resulting in a lack of leaflet coaptation. In the ischemic MV with balanced leaflet tenting, mitral incompetency with incomplete leaflet coaptation was clearly identified all around the paracommissural regions. This computational MV evaluation strategy has the potential for improving diagnosis of ischemic mitral regurgitation and treatment of ischemic MVs. PMID:24211876

  12. Genetic Risk Factors for Perinatal Arterial Ischemic Stroke

    PubMed Central

    Gelfand, Amy A.; Croen, Lisa A.; Torres, Anthony R.; Wu, Yvonne W.

    2012-01-01

    The cause of perinatal arterial ischemic stroke is unknown in most cases. We explored whether genetic polymorphisms modify the risk of perinatal arterial ischemic stroke. In a population-based case-control study of 1997–2002 births at Kaiser Permanente Northern California, we identified 13 white infants with perinatal arterial ischemic stroke. Controls included 86 randomly selected white infants. We genotyped polymorphisms in 9 genes involved in inflammation, thrombosis or lipid metabolism that have been previously linked with stroke, and compared genotype frequencies in case and control individuals. We tested the following polymorphisms: TNF-?-308, IL-6, lymphotoxin A, factor V Leiden, MTHFR 1298 and 667, prothrombin 20210, and apolipoprotein E ?2 and ?4 alleles. Patients with perinatal arterial ischemic stroke were more likely than controls to have at least one apolipoprotein E ?4 allele (54% vs. 25%, p=0.03). More patients with perinatal arterial ischemic stroke carried two ?4 alleles than did controls (15% vs. 2%, p=0.09), though this finding was not statistically significant. Proinflammatory and prothrombotic polymorphisms were not associated with perinatal arterial ischemic stroke in this small study. The apolipoprotein E polymorphism may confer genetic susceptibility for perinatal arterial ischemic stroke. Larger population-based studies are needed to confirm this finding. PMID:23290018

  13. IP Initialization The IP module is initialized when ip_init() is called from the last few lines of inet_init(). This

    E-print Network

    Westall, James M.

    by destination IP address to the routing entities describing the next hop and the FIB (Forwarding Information_initpeers() initializes the AVL tree used to keep track of IP peers, hosts with which this host has recently exchanged pointers of type *rtable and *dst_entry to be used interchangeably. Fields of type __u32 are IP addresses

  14. Surgical Treatment of Moderate Ischemic Mitral Regurgitation

    PubMed Central

    Smith, P.K.; Puskas, J.D.; Ascheim, D.D.; Voisine, P.; Gelijns, A.C.; Moskowitz, A.J.; Hung, J.W.; Parides, M.K.; Ailawadi, G.; Perrault, L.P.; Acker, M.A.; Argenziano, M.; Thourani, V.; Gammie, J.S.; Miller, M.A.; Pagé, P.; Overbey, J.R.; Bagiella, E.; Dagenais, F.; Blackstone, E.H.; Kron, I.L.; J., D.; Rose, E.A.; Moquete, E.G.; Jeffries, N.; Gardner, T.J.; O’Gara, P.T.; Alexander, J.H.; Michler, R.E.

    2015-01-01

    BACKGROUND Ischemic mitral regurgitation is associated with increased mortality and morbidity. For surgical patients with moderate regurgitation, the benefits of adding mitral-valve repair to coronary-artery bypass grafting (CABG) are uncertain. METHODS We randomly assigned 301 patients with moderate ischemic mitral regurgitation to CABG alone or CABG plus mitral-valve repair (combined procedure). The primary end point was the left ventricular end-systolic volume index (LVESVI), a measure of left ventricular remodeling, at 1 year. This end point was assessed with the use of a Wilcoxon rank-sum test in which deaths were categorized as the lowest LVESVI rank. RESULTS At 1 year, the mean LVESVI among surviving patients was 46.1±22.4 ml per square meter of body-surface area in the CABG-alone group and 49.6±31.5 ml per square meter in the combined-procedure group (mean change from baseline, ?9.4 and ?9.3 ml per square meter, respectively). The rate of death was 6.7% in the combined-procedure group and 7.3% in the CABG-alone group (hazard ratio with mitral-valve repair, 0.90; 95% confidence interval, 0.38 to 2.12; P = 0.81). The rank-based assessment of LVESVI at 1 year (incorporating deaths) showed no significant between-group difference (z score, 0.50; P = 0.61). The addition of mitral-valve repair was associated with a longer bypass time (P<0.001), a longer hospital stay after surgery (P = 0.002), and more neurologic events (P = 0.03). Moderate or severe mitral regurgitation was less common in the combined-procedure group than in the CABG-alone group (11.2% vs. 31.0%, P<0.001). There were no significant between-group differences in major adverse cardiac or cerebrovascular events, deaths, readmissions, functional status, or quality of life at 1 year. CONCLUSIONS In patients with moderate ischemic mitral regurgitation, the addition of mitral-valve repair to CABG did not result in a higher degree of left ventricular reverse remodeling. Mitral-valve repair was associated with a reduced prevalence of moderate or severe mitral regurgitation but an increased number of untoward events. Thus, at 1 year, this trial did not show a clinically meaningful advantage of adding mitral-valve repair to CABG. Longer-term follow-up may determine whether the lower prevalence of mitral regurgitation translates into a net clinical benefit. (Funded by the National Institutes of Health and the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00806988.) PMID:25405390

  15. Ketogenic Diet Provides Neuroprotective Effects against Ischemic Stroke Neuronal Damages

    PubMed Central

    Shaafi, Sheyda; Mahmoudi, Javad; Pashapour, Ali; Farhoudi, Mehdi; Sadigh-eteghad, Saeed; Akbari, Hossein

    2014-01-01

    Ischemic stroke is a leading cause of death and disability in the world. Many mechanisms contribute in cell death in ischemic stroke. Ketogenic diet which has been successfully used in the drug-resistant epilepsy has been shown to be effective in many other neurologic disorders. The mechanisms underlying of its effects are not well studied, but it seems that its neuroprotective ability is mediated at least through alleviation of excitotoxicity, oxidative stress and apoptosis events. On the basis of these mechanisms, it is postulated that ketogenic diet could provide benefits to treatment of cerebral ischemic injuries. PMID:25671178

  16. Use of nitrates in ischemic heart disease.

    PubMed

    Giuseppe, Cocco; Paul, Jerie; Hans-Ulrich, Iselin

    2015-08-01

    Short-acting nitrates are beneficial in acute myocardial ischemia. However, many unresolved questions remain about the use of long-acting nitrates in stable ischemic heart disease. The use of long-acting nitrates is weakened by the development of endothelial dysfunction and tolerance. Also, we currently ignore whether lower doses of transdermal nitroglycerin would be better than those presently used. Multivariate analysis data from large nonrandomized studies suggested that long-acting nitrates increase the incidence of acute coronary syndromes, while data from another multivariate study indicate that they have positive effects. Because of methodological differences and open questions, the two studies cannot be compared. A study in Japanese patients with vasospastic angina has shown that, when compared with calcium antagonists, long-acting nitrates do not improve long-term prognosis and that the risk for cardiac adverse events increases with the combined therapy. We have many unanswered questions. PMID:26027641

  17. [Diagnostic and treatment of acute ischemic stroke].

    PubMed

    Weimar, C; Weber, R; Schlamann, M; Hajjar, K; Buck, T; Diener, H C

    2013-03-01

    The incidence of first stroke in Germany is about 200.000, most of which are ischemic. The benefit of stroke unit treatment and systemic thrombolysis has been shown in large randomized trials. Diagnostic work-up besides neurologic examination includes cerebral imaging by CT or MR imaging including angiography, ultrasound of brain supplying arteries, ECG and Holter ECG and - if indicated - transesophageal echocardiography. Aspirin is the cornerstone of early secondary prevention in the acute phase, thereafter secondary prevention is determined by stroke etiology. Carotid endarterectomy or stent-assisted angioplasty are indicated in patients with hemodynamic or arterio-arterial stroke etiologies due to high-grade carotid stenosis. For cardioembolism due to atrial fibrillation, oral anticoagulation with vitamin K-antagonists or new oral anticoagulants should be started after the acute phase. In patients with non-cardioembolic stroke etiologies, platelet inhibitors are used for secondary prevention. PMID:23423939

  18. Ischemic heart disease and heart weight.

    PubMed

    Romppanen, T; Seppä, A; Roilas, H

    1983-01-01

    Separate weights for heart ventricle walls and interventricular septa were analyzed in 110 hearts with autopsy findings of ischemic heart disease (coronary atherosclerosis, recent or old myocardial infarcts) and with no other cardiac or systemic causes of cardiac enlargement. In hearts with coronary atherosclerosis alone (without old or recent myocardial infarcts) no weight increase was observed in the left ventricle when compared to 29 controls. Patients having infarcts associated with nonstenosing atherosclerosis (less than 50% of the luminal diameter narrowed) of the coronaries had normal heart weights as well. On the contrary, infarcts associated with stenosing coronary sclerosis (narrowing more than 50%) showed significant signs of left ventricular weight increase, which is interpreted as compensatory heart hypertrophy. The greatest degree of hypertrophy was observed in hearts with left ventricular aneurysms. PMID:6640561

  19. Remote ischemic conditioning: Current clinical perspectives.

    PubMed

    Le Page, Sophie; Prunier, Fabrice

    2015-08-01

    Remote ischemic conditioning (RIC) constitutes a promising method in which a tissue or organ is exposed to intermittent ischemia/reperfusion periods enabling it to provide protection to a distant target organ. RIC has been tested in various clinical settings through its simple application by means of intermittent inflation of a blood pressure cuff placed on a limb, primarily evaluating its potential abilities to decrease myocardial injury biomarkers. Its use on other organs, such as the kidneys or brain, has recently been a topic of research. To date, no study has yet been powerful enough to reach a conclusion on the potential benefit of RIC on clinical outcomes. The future role of RIC in the clinical arena could be clarified by the large phase III trials currently underway targeting major outcomes as primary endpoints. PMID:25744784

  20. Hypothermia for newborns with hypoxic ischemic encephalopathy.

    PubMed

    Peliowski-Davidovich, Abraham

    2012-01-01

    Hypoxic ischemic encephalopathy (HIE) remains a significant cause of mortality and long-term disability in late preterm and term infants. Mild therapeutic hypothermia to a rectal temperature of 34±0.5°C initiated as soon as possible within the first 6 h of life decreases mortality and severe long-term neurodevelopmental disabilities in infants with moderate HIE who are ?36 weeks' gestational age. There are minimal side effects, and the incidence of disability in survivors is not increased. Infants with severe encephalopathy are less likely to benefit from treatment. Cooling may be achieved by either total body or selective head cooling. As cooling is now considered a standard of care, infants ?36 weeks' gestational age who are depressed at birth should be assessed to determine whether they meet the criteria for cooling. There is currently no evidence that therapeutic hypothermia offers any benefit to infants <36 weeks' gestational age. PMID:23277757

  1. Targeting Neovascularization in Ischemic Retinopathy: Recent Advances

    PubMed Central

    Al-Shabrawey, Mohamed; Elsherbiny, Mohamed; Nussbaum, Julian; Othman, Amira; Megyerdi, Sylvia; Tawfik, Amany

    2014-01-01

    Pathological retinal neovascularization (RNV) is a common micro-vascular complication in several retinal diseases including retinopathy of prematurity, diabetic retinopathy, age-related macular degeneration and central vein occlusion. The current therapeutic modalities of RNV are invasive and although they may slow or halt the progression of the disease they are unlikely to restore normal acuity. Therefore, there is an urgent need to develop treatment modalities, which are less invasive and therefore associated with fewer procedural complications and systemic side effects. This review article summarizes our understanding of the pathophysiology and current treatment of RNV in ischemic retinopathies; lists potential therapeutic targets; and provides a framework for the development of future treatment modalities. PMID:25598837

  2. Volkmann ischemic contracture in a newborn

    PubMed Central

    Rios, Marta; Ribeiro, Cristiana; Soares, Paula; Amorim, Rosa; Osório, Angélica; Leitão, Banquart; Almeida, Alexandra

    2011-01-01

    Congenital Volkmann ischemic contracture is a very rare condition in which a neonate presents skin, muscular and nerve lesions due to increased intracompartment pressure and subsequent ischemia, probably due to extrinsic intrauterine compression. In this age group, there are only about 50 reported cases and a specific cause is unknown. The authors describe the case of a newborn who presented with bullous and ulcerated skin lesions and nerve palsy of his forearm at birth, evolving to subcutaneous and muscular necrosis and contracture. Two surgeries were performed and the baby began a daily physiotherapy program that resulted in aesthetical improvement and recovery of his hand and forearm mobility. Early recognition of this rare entity and subsequent emergency fasciotomy are the best ways to improve prognosis. PMID:22679268

  3. Analysis of physics-based preconditioning for single-phase subchannel equations

    SciTech Connect

    Hansel, J. E.; Ragusa, J. C. [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77840 (United States); Allu, S.; Berrill, M. A.; Clarno, K. T. [Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831 (United States)

    2013-07-01

    The (single-phase) subchannel approximations are used throughout nuclear engineering to provide an efficient flow simulation because the computational burden is much smaller than for computational fluid dynamics (CFD) simulations, and empirical relations have been developed and validated to provide accurate solutions in appropriate flow regimes. Here, the subchannel equations have been recast in a residual form suitable for a multi-physics framework. The Eigen spectrum of the Jacobian matrix, along with several potential physics-based preconditioning approaches, are evaluated, and the the potential for improved convergence from preconditioning is assessed. The physics-based preconditioner options include several forms of reduced equations that decouple the subchannels by neglecting crossflow, conduction, and/or both turbulent momentum and energy exchange between subchannels. Eigen-scopy analysis shows that preconditioning moves clusters of eigenvalues away from zero and toward one. A test problem is run with and without preconditioning. Without preconditioning, the solution failed to converge using GMRES, but application of any of the preconditioners allowed the solution to converge. (authors)

  4. Oleanolic Acid Enhances the Beneficial Effects of Preconditioning on PC12 Cells

    PubMed Central

    Daniels, Willie M. U.; Mabandla, Musa V.

    2014-01-01

    Preconditioning triggers endogenous protection against subsequent exposure to higher concentrations of a neurotoxin. In this study, we investigated whether exposure to oleanolic acid (OA) enhances the protective effects of preconditioning on PC12 cells exposed to 6-hydroxydopamine (6-OHDA). A concentration response curve was constructed using 6-OHDA (50, 150, 300, and 600??M). The experiment consisted of 6 groups: untreated, OA only, Group 1: cells treated with 6-OHDA (50??M) for 1 hour, Group 2: cells treated with 6-OHDA (150??M) for 1 hour, Group 3: cells treated with 6-OHDA (50??M) for 30 minutes followed 6 hours later by treatment with 6-OHDA (150??M) for 30 minutes, and Group 4: cells treated as in group 3 but also received OA immediately after the second 6-OHDA treatment. Cell viability and apoptotic ratio were assessed using the MTT and Annexin V staining tests, respectively. In preconditioned cells, we found that cell viability remained high following exposure to 6-OHDA (150??M). OA treatment enhanced the protective effects of preconditioning. Similarly, with the annexin V apoptosis test, preconditioning protected the cell and this was enhanced by OA. Therefore, preexposure of PC12 cells to low 6-OHDA concentration can protect against subsequent toxic insults of 6-OHDA and OA enhances this protection. PMID:25478286

  5. Super-low Dose Endotoxin Pre-conditioning Exacerbates Sepsis Mortality

    PubMed Central

    Chen, Keqiang; Geng, Shuo; Yuan, Ruoxi; Diao, Na; Upchurch, Zachary; Li, Liwu

    2015-01-01

    Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks. PMID:26029736

  6. Preconditioning of Microglia by ?-Synuclein Strongly Affects the Response Induced by Toll-like Receptor (TLR) Stimulation

    PubMed Central

    Gonzalez-Rey, Elena; Lachaud, Christian C.; Guilliams, Tim; Fernandez-Montesinos, Rafael; Benitez-Rondan, Alicia; Robledo, Gema; Hmadcha, Abdelkrim; Delgado, Mario; Dobson, Christopher M.; Pozo, David

    2013-01-01

    In recent years, it has become accepted that ?-synuclein (?Syn) has a key role in the microglia-mediated neuroinflammation, which accompanies the development of Parkinson’s disease and other related disorders, such as Dementia with Lewy Bodies and Alzheimer’s disease. Nevertheless, the cellular and molecular mechanisms underlying its pathological actions, especially in the sporadic forms of the diseases, are not completely understood. Intriguingly, several epidemiological and animal model studies have revealed a link between certain microbial infections and the onset or progression of sporadic forms of these neurodegenerative disorders. In this work, we have characterized the effect of toll-like receptor (TLR) stimulation on primary murine microglial cultures and analysed the impact of priming cells with extracellular wild-type (Wt) ?Syn on the subsequent TLR stimulation of cells with a set of TLR ligands. By assaying key interleukins and chemokines we report that specific stimuli, in particular Pam3Csk4 (Pam3) and single-stranded RNA40 (ssRNA), can differentially affect the TLR2/1- and TLR7-mediated responses of microglia when pre-conditioned with ?Syn by augmenting IL-6, MCP-1/CCL2 or IP-10/CXCL10 secretion levels. Furthermore, we report a skewing of ?Syn-primed microglia stimulated with ssRNA (TLR7) or Pam3 (TLR2/1) towards intermediate but at the same time differential, M1/M2 phenotypes. Finally, we show that the levels and intracellular location of activated caspase-3 protein change significantly in ?Syn-primed microglia after stimulation with these particular TLR agonists. Overall, we report a remarkable impact of non-aggregated ?Syn pre-sensitization of microglia on TLR-mediated immunity, a phenomenon that could contribute to triggering the onset of sporadic ?-synuclein-related neuropathologies. PMID:24236103

  7. Space-Based Voice over IP Networks

    NASA Technical Reports Server (NTRS)

    Nguyen, Sam P.; Okino, Clayton; Walsh, William; Clare, Loren

    2007-01-01

    In human space exploration missions (e.g. a return to the Moon and for future missions to Mars), there will be a need to provide voice communications services. In this work we focus on the performance of Voice over IP (VoIP) techniques applied to space networks, where long range latencies, simplex links, and significant bit error rates occur. Link layer and network layer overhead issues are examined. Finally, we provide some discussion on issues related to voice conferencing in the space network environment.

  8. An overview of NSPCG: A nonsymmetric preconditioned conjugate gradient package

    NASA Astrophysics Data System (ADS)

    Oppe, Thomas C.; Joubert, Wayne D.; Kincaid, David R.

    1989-05-01

    The most recent research-oriented software package developed as part of the ITPACK Project is called "NSPCG" since it contains many nonsymmetric preconditioned conjugate gradient procedures. It is designed to solve large sparse systems of linear algebraic equations by a variety of different iterative methods. One of the main purposes for the development of the package is to provide a common modular structure for research on iterative methods for nonsymmetric matrices. Another purpose for the development of the package is to investigate the suitability of several iterative methods for vector computers. Since the vectorizability of an iterative method depends greatly on the matrix structure, NSPCG allows great flexibility in the operator representation. The coefficient matrix can be passed in one of several different matrix data storage schemes. These sparse data formats allow matrices with a wide range of structures from highly structured ones such as those with all nonzeros along a relatively small number of diagonals to completely unstructured sparse matrices. Alternatively, the package allows the user to call the accelerators directly with user-supplied routines for performing certain matrix operations. In this case, one can use the data format from an application program and not be required to copy the matrix into one of the package formats. This is particularly advantageous when memory space is limited. Some of the basic preconditioners that are available are point methods such as Jacobi, Incomplete LU Decomposition and Symmetric Successive Overrelaxation as well as block and multicolor preconditioners. The user can select from a large collection of accelerators such as Conjugate Gradient (CG), Chebyshev (SI, for semi-iterative), Generalized Minimal Residual (GMRES), Biconjugate Gradient Squared (BCGS) and many others. The package is modular so that almost any accelerator can be used with almost any preconditioner.

  9. Therapeutically Targeting Neuroinflammation and Microglia after Acute Ischemic Stroke

    PubMed Central

    Lee, Sang-Rae; Choi, Sung S.; Chang, Kyu-Tae

    2014-01-01

    Inflammation has a pivotal role in the pathogenesis of ischemic stroke, and recent studies posit that inflammation acts as a double-edged sword, not only detrimentally augmenting secondary injury, but also potentially promoting recovery. An initial event of inflammation in ischemic stroke is the activation of microglia, leading to production of both pro- and anti-inflammatory mediators acting through multiple receptor signaling pathways. In this review, we discuss the role of microglial mediators in acute ischemic stroke and elaborate on preclinical and clinical studies focused on microglia in stroke models. Understanding how microglia can lead to both pro- and anti-inflammatory responses may be essential to implement therapeutic strategies using immunomodulatory interventions in ischemic stroke. PMID:25089266

  10. Sildenafil-associated nonarteritic anterior ischemic optic neuropathy

    Microsoft Academic Search

    Howard D Pomeranz; Kyle H Smith; William M Hart; Robert A Egan

    2002-01-01

    PurposeTo describe the clinical features of five patients who developed nonarteritic anterior ischemic optic neuropathy (NAION) after ingestion of sildenafil citrate (Viagra; Pfizer Pharmaceuticals, New York, NY).

  11. Simulation of conformational preconditioning strategies for electrophoretic stretching of DNA in a microcontraction

    PubMed Central

    Hsieh, Chih-Chen; Lin, Tsung-Hsien

    2011-01-01

    We have used Brownian dynamics-finite element method to examine two conformational preconditioning approaches for improving DNA stretching in a microcontraction for the purpose of direct gene analysis. The newly proposed “pre-stretching” strategy is found to significantly improve the degree of DNA extension at the exit of the contraction. On the other hand, applying an oscillating extensional field to DNA yields no preconditioning effect. Detailed analysis of the evolution of DNA extension and conformation reveals that the success of our “pre-stretching” strategy relies on the “non-local” effect that cannot be predicted using simple kinematics analysis. In other words, accurate prediction can only be obtained using detailed simulations. Comparing to the existing preconditioning strategies, our “pre-stretching” method is easy to implement while still providing a very good performance. We hope that the insight gained from this study can be useful for future design of biomicrofluidic devices for DNA manipulation. PMID:22662058

  12. Novel Genes Critical for Hypoxic Preconditioning in Zebrafish Are Regulators of Insulin and Glucose Metabolism

    PubMed Central

    Manchenkov, Tania; Pasillas, Martina P.; Haddad, Gabriel G.; Imam, Farhad B.

    2015-01-01

    Severe hypoxia is a common cause of major brain, heart, and kidney injury in adults, children, and newborns. However, mild hypoxia can be protective against later, more severe hypoxia exposure via “hypoxic preconditioning,” a phenomenon that is not yet fully understood. Accordingly, we have established and optimized an embryonic zebrafish model to study hypoxic preconditioning. Using a functional genomic approach, we used this zebrafish model to identify and validate five novel hypoxia-protective genes, including irs2, crtc3, and camk2g2, which have been previously implicated in metabolic regulation. These results extend our understanding of the mechanisms of hypoxic preconditioning and affirm the discovery potential of this novel vertebrate hypoxic stress model. PMID:25840431

  13. Incomplete Gaussian elimination as a preconditioning for generalized conjugate gradient acceleration

    SciTech Connect

    Wallis, J.R.

    1983-11-01

    This paper discusses the application of preconditioned generalized conjugate gradient acceleration to fully implicit thermal simulation. The preconditioning step utilizes incomplete Gaussian elimination (IGE) to form an approximate factorization of the Jacobian matrix. IGE preconditioning and its implementation is discussed with respect to five, seven, nine or eleven-point finite difference approximations and optional well constraint equations. Numerical results were obtained using a thermal model allowing any number N/SUB c/ of components. The model's implicit formulation requires the solution of a linear system of equations in which each grid block has N /SUB c/ + 1 unknowns. Test problems involved combustion, steam drive and cyclic steam stimulation processes, some of which exhibited ill-conditioning, negative transmissabilities and high transmissability ratios. Numerical results indicate how different grid block orderings, different levels of incomplete factorization and different acceleration procedures affect convergence, storage and work requirements.

  14. Peri-operative anaesthetic myocardial preconditioning and protection - cellular mechanisms and clinical relevance in cardiac anaesthesia.

    PubMed

    Kunst, G; Klein, A A

    2015-04-01

    Preconditioning has been shown to reduce myocardial damage caused by ischaemia-reperfusion injury peri-operatively. Volatile anaesthetic agents have the potential to provide myocardial protection by anaesthetic preconditioning and, in addition, they also mediate renal and cerebral protection. A number of proof-of-concept trials have confirmed that the experimental evidence can be translated into clinical practice with regard to postoperative markers of myocardial injury; however, this effect has not been ubiquitous. The clinical trials published to date have also been too small to investigate clinical outcome and mortality. Data from recent meta-analyses in cardiac anaesthesia are also not conclusive regarding intra-operative volatile anaesthesia. These inconclusive clinical results have led to great variability currently in the type of anaesthetic agent used during cardiac surgery. This review summarises experimentally proposed mechanisms of anaesthetic preconditioning, and assesses randomised controlled clinical trials in cardiac anaesthesia that have been aimed at translating experimental results into the clinical setting. PMID:25764404

  15. Efficient Multi-Stage Time Marching for Viscous Flows via Local Preconditioning

    NASA Technical Reports Server (NTRS)

    Kleb, William L.; Wood, William A.; vanLeer, Bram

    1999-01-01

    A new method has been developed to accelerate the convergence of explicit time-marching, laminar, Navier-Stokes codes through the combination of local preconditioning and multi-stage time marching optimization. Local preconditioning is a technique to modify the time-dependent equations so that all information moves or decays at nearly the same rate, thus relieving the stiffness for a system of equations. Multi-stage time marching can be optimized by modifying its coefficients to account for the presence of viscous terms, allowing larger time steps. We show it is possible to optimize the time marching scheme for a wide range of cell Reynolds numbers for the scalar advection-diffusion equation, and local preconditioning allows this optimization to be applied to the Navier-Stokes equations. Convergence acceleration of the new method is demonstrated through numerical experiments with circular advection and laminar boundary-layer flow over a flat plate.

  16. Exogenous low dose hydrogen peroxide increases hypoxia-inducible factor-1alpha protein expression and induces preconditioning protection against ischemia in primary cortical neurons

    Microsoft Academic Search

    Shengjun Chang; Xiangning Jiang; Chong Zhao; Christina Lee; Donna M. Ferriero

    2008-01-01

    HIF-1 is believed to play a critical role in hypoxia\\/ischemia (H\\/I) preconditioning protection in neonatal brain. Recently, it has been shown that hydrogen peroxide (H2O2) may contribute to H\\/I preconditioning in rat primary neurons. We hypothesize that H2O2 produced during H\\/I preconditioning may increase HIF-1? protein expression and contribute to H\\/I preconditioning protection in the immature brain. To test this

  17. Inhibition of HDAC2 Protects the Retina From Ischemic Injury

    PubMed Central

    Fan, Jie; Alsarraf, Oday; Dahrouj, Mohammad; Platt, Kenneth A.; Chou, C. James; Rice, Dennis S.; Crosson, Craig E.

    2013-01-01

    Purpose. Protein acetylation is an essential mechanism in regulating transcriptional and inflammatory events. Studies have shown that nonselective histone deacetylase (HDAC) inhibitors can protect the retina from ischemic injury in rats. However, the role of specific HDAC isoforms in retinal degenerative processes remains obscure. The purpose of this study was to investigate the role of HDAC2 isoform in a mouse model of ischemic retinal injury. Methods. Localization of HDAC2 in mice retinas was evaluated by immunohistochemical analyses. To investigate whether selective reduction in HDAC2 activity can protect the retina from ischemic injury, Hdac2+/? mice were utilized. Electroretinographic (ERG) and morphometric analyses were used to assess retinal function and morphology. Results. Our results demonstrated that HDAC2 is primarily localized in nuclei in inner nuclear and retinal ganglion cell layers, and HDAC2 activity accounted for approximately 35% of the total activities of HDAC1, 2, 3, and 6 in the retina. In wild-type mice, ERG a- and b-waves from ischemic eyes were significantly reduced when compared to pre-ischemia baseline values. Morphometric examination of these eyes revealed significant degeneration of inner retinal layers. In Hdac2+/? mice, ERG a- and b-waves from ischemic eyes were significantly greater than those measured in ischemic eyes from wild-type mice. Morphologic measurements demonstrated that Hdac2+/? mice exhibit significantly less retinal degeneration than wild-type mice. Conclusions. This study demonstrated that suppressing HDAC2 expression can effectively reduce ischemic retinal injury. Our results support the idea that the development of selective HDAC2 inhibitors may provide an efficacious treatment for ischemic retinal injury. PMID:23696608

  18. Contribution of Hematocrit to Early Mortality after Ischemic Stroke

    Microsoft Academic Search

    Simona Sacco; Carmine Marini; Luigi Olivieri; Francesca Pistoia; Antonio Carolei

    2007-01-01

    Background: Only a few non-recent studies assessed the importance of hematocrit (HCT) in patients with ischemic stroke. We evaluated how HCT might affect early mortality after stroke. Methods: We investigated all first-ever ischemic strokes included in the population-based L’Aquila registry. 3,481 patients according to HCT (%) values were included into four categories (?40, 41–45, 46–50, and >50). Results: There were

  19. Perioperative ischemic stroke in non-cardiovascular surgery patients

    Microsoft Academic Search

    Mutsuhito KikuraBrian; Brian T. Bateman; Kenichi A. Tanaka

    2010-01-01

    Perioperative ischemic stroke occurs in approximately 0.08–0.7% of patients after non-cardiovascular surgery and confers a\\u000a significant risk of morbidity and mortality. The mortality rate of this major complication is similar in non-cardiovascular\\u000a and cardiovascular surgery. Its incidence appears to be similar in Japan, Europe, and the United States. Perioperative physicians\\u000a should be aware of the pathophysiology and predictors of ischemic

  20. Statistical prediction of tissue fate in acute ischemic brain injury

    Microsoft Academic Search

    Qiang Shen; Hongxia Ren; Marc Fisher; Timothy Q. Duong

    2005-01-01

    An algorithm was developed to statistically predict ischemic tissue fate on a pixel-by-pixel basis. Quantitative high-resolution (200 x 200 microm) cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were measured on acute stroke rats subjected to permanent middle cerebral artery occlusion and an automated clustering (ISODATA) technique was used to classify ischemic tissue types. Probability and probability density profiles