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Pivot Concepts:
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Query: EC:3.1.27.1 (
RNase
)
16,360
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Dexamethasone (DEX) increases the expression of neurotrophin-3 (NT-3) in normal rat hippocampal neurons, whereas transient forebrain
ischemia
reduces the NT-3 mRNA level. The effect of DEX on the expression of NT-3 mRNA in injured brain cells after
ischemia
has not been investigated, however. Using in situ hybridization and
ribonuclease
protection assay methods, we studied NT-3 mRNA expression in rats with and without DEX administration after transient forebrain
ischemia
. Without DEX treatment, NT-3 mRNA was down-regulated in the hippocampal neurons at 2, 4, 12 h and returned to basal levels 24 h following
ischemia
. With DEX treatment, however, NT-3 mRNA showed no change at 2, 4 and 12 h and increased 24 h after
ischemia
. The results indicate that DEX inhibits
ischemia
-induced NT-3 mRNA down-regulation during the first 12 h and up-regulates NT-3 mRNA 24 h after
ischemia
. DEX administration might be effective in influencing some of the pathophysiological effects of
ischemia
in the hippocampus.
...
PMID:Dexamethasone inhibits ischemia-induced transient reduction of neurotrophin-3 mRNA in rat hippocampal neurons. 985 2
In the newborn, cyclooxygenase (COX)-derived products play an important role in the cerebrovascular dysfunction after
ischemia
-reperfusion (I/R). We examined effects of I/R on expression of COX-1 and COX-2 isoforms in large cerebral arteries of anesthetized piglets. The circle of Willis, the basilar, and the middle cerebral arteries were collected from piglets at 0.5-12 h after global
ischemia
(2.5-10 min, n = 50), hypoxia (n = 3), or hypercapnia (n = 2) and from time-control (n = 19) or untreated animals (n = 7). Tissues were analyzed for COX-1 and COX-2 mRNA and protein using
RNase
protection assay and immunoblot analysis, respectively.
Ischemia
increased COX-2 mRNA by 30 min, and maximal levels were reached at 2 h. Hypoxia or hypercapnia had minimal effects on COX-2 mRNA. COX-2 protein levels were also consistently elevated by 8 h after I/R. Increases in COX-2 mRNA or protein were not influenced by pretreatment with either indomethacin (5 mg/kg iv, n = 5) or nitro-L-arginine methyl ester (15 mg/kg iv, n = 7). COX-1 mRNA levels were low in time controls, and ischemic stress had no significant effect on COX-1 expression. Thus ischemic stress leads to relatively rapid, selective induction of COX-2 in cerebral arteries.
...
PMID:Ischemia-reperfusion rapidly increases COX-2 expression in piglet cerebral arteries. 1048 43
Reperfusion of the ischemic myocardium is associated with a cytokine cascade that reflects a cellular response to injury. We studied this cascade in the mouse and found that acute surgical trauma in sham-operated animals obscured early changes in cytokine induction that occur during myocardial ischemia-reperfusion (MI/R). Therefore, we utilized a new implantable device that allows occlusion and reperfusion of the left anterior descending coronary artery in a closed-chest mouse at any time after instrumentation. Induction of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha mRNA in the whole heart was examined by
RNase
protection assay and quantitated by Phosphor- Imager. At 3 h after instrumentation, levels of IL-6 mRNA in sham-operated animals increased above those of control naive hearts, whereas this increase did not occur until after 1 day for TNF-alpha mRNA. The surgical trauma led to exaggeration of I/R cytokine induction with greater variance in response. At 3 days and 1 wk after instrumentation, levels of both IL-6 and TNF-alpha mRNA in sham-operated animals were comparable to those of naive hearts and induction responses in I/R were much less variant. We also found that 1 h of
ischemia
and 2 h of reperfusion at all time points of recovery (i.e., 3 h and 1, 3, and 7 days after instrumentation) led to a significant increase in IL-6 and TNF-alpha mRNA levels. In addition, 3 h of permanent occlusion, which did not induce any mRNA increase after 1 wk postinstrumentation, caused marked upregulation of IL-6 mRNA in an acutely prepared animal. This study of early cytokine responses evoked by MI/R highlights the need for dissipation of acute surgical trauma by using a chronic, closed-chest mouse preparation.
...
PMID:A chronic mouse model of myocardial ischemia-reperfusion: essential in cytokine studies. 1074 92
Ischemia
-reperfusion injury (IRI) is a major cause of renal dysfunction in both native kidneys and renal allografts. To broaden our understanding of the inflammatory mediators involved in IRI, we used multi-probe
RNase
protection assays to examine the expression of 26 different cytokine genes in a murine model of renal IRI. We observed that, in addition to up-regulation of IL-1beta and to a lesser extent TNF-alpha, IRI was associated with an intense and sustained up-regulation of three gp130-signaling cytokines, IL-6, IL-11, and leukemia inhibitory factor (LIF), as well as with up-regulation of the neutrophil chemotactic and activating mediator macrophage inflammatory protein (MIP)-2. Macrophage colony-stimulating factor (M-CSF) and monocyte chemoattractant protein (MCP)-1 were also moderately up-regulated after IRI, whereas mRNA levels of several other inflammatory mediators including IL-1alpha, IL-2, IL-4, interferon (IFN)-gamma, GM-CSF, and RANTES were minimally increased or remained undetectable. These findings identify MIP-2 as an attractive target for inhibition of leukocyte recruitment in renal IRI and also suggest a potentially novel role for gp130-mediated signals in IRI.
...
PMID:Prominent and sustained up-regulation of gp130-signaling cytokines and the chemokine MIP-2 in murine renal ischemia-reperfusion injury. 1075 57
Classic ischemic preconditioning transiently (30 to 120 minutes) protects the myocardium against subsequent lethal
ischemia
/reperfusion injury. After dissipation of this acute protection, a second window of protection (SWOP) appears 12 to 24 hours later; this SWOP lasts up to 3 days. Several triggers induce a SWOP, including brief repetitive cycles of coronary artery occlusion, rapid ventricular pacing, stimulation of adenosine A(1) receptors, and administration of wall fragments of Gram-negative bacteria, such as lipopolysaccharide (LPS). The aim of this study was to investigate whether lipoteichoic acid (LTA), a cell wall fragment of Gram-positive bacteria, can induce a SWOP in a rat model of left anterior descending coronary artery (LAD) occlusion (25 minutes) and reperfusion (2 hours). Thus, 166 male Wistar rats were pretreated (2 to 24 hours) with saline, LTA (1 mg/kg IP), or LPS (1 mg/kg IP) and subjected to LAD occlusion/reperfusion. Pretreatment with LTA or LPS for 16 hours led to a substantial, approximately 65%, reduction in infarct size and a reduction in the release of cardiac troponin T into the plasma. The dose of LTA used had no toxic effect (on any of the parameters studied), whereas the same dose of LPS caused a time-dependent activation of the coagulation system and liver injury. By use of
RNase
protection assays, it was determined that LPS caused a time-dependent induction of tumor necrosis factor-alpha, interleukin-1beta, and manganese superoxide dismutase mRNA content in the heart, whereas LTA failed to induce manganese superoxide dismutase. LPS also caused an upregulation of the expression of intercellular adhesion molecule-1 and P-selectin, whereas LTA downregulated these molecules and attenuated the accumulation of polymorphonuclear granulocytes caused by myocardial ischemia/reperfusion. This study demonstrates for the first time that pretreatment with LTA at 8 to 24 hours before myocardial ischemia significantly reduces (1) infarct size, (2) cardiac troponin T, and (3) the histological signs of tissue injury in rats subjected to LAD occlusion and reperfusion. The mechanism(s) underlying the observed cardioprotective effects of LTA warrants further investigation but is likely to be related to its ability to inhibit the interactions between the coronary vascular endothelium and polymorphonuclear granulocytes. Therefore, LTA represents a novel and promising agent capable of enhancing myocardial tolerance to
ischemia
/reperfusion injury.
...
PMID:Lipoteichoic acid induces delayed protection in the rat heart: A comparison with endotoxin. 1084 67
The present study investigates the molecular apoptotic pathway in germ cells following acute
ischemia
of the rat testis. Rats were subjected to
ischemia
-inducing torsion and testes were harvested after reperfusion. Apoptotic cells were identified with an antibody to single-stranded DNA. Seminiferous tubule RNA was examined by
RNase
protection assay or by reverse transcriptase-polymerase chain reaction (RT-PCR) for the presence and regulation of apoptotic molecules. Proteins from seminiferous tubules were used for Western blot analysis of cytochrome c. Germ cell apoptosis was maximal at 24 h after repair of torsion. Germ cells in stages II-III of the seminiferous epithelium cycle were the predominant early responders. The
RNase
protection assays revealed that Bcl-X(L) was the prominent mRNA species. Caspases 1, 2, 3, and Bax mRNA were consistently upregulated; however, the time of upregulation after torsion was variable. The Bcl-X(L) and Bcl-X(S) mRNAs were less consistently upregulated and there was no evidence for upregulation of Fas or Bcl-2. Fas ligand (FasL) was not detected by
RNase
protection assay, but RT-PCR revealed a significant increase in FasL expression 4 h after the repair of torsion. Western blot analysis for cytochrome c release demonstrated a significant increase 4 h after the repair of torsion. Results suggest that germ cell apoptosis following
ischemia
/reperfusion of the rat testis is initiated through the mitochondria-associated molecule Bax as well as Fas-FasL interactions.
...
PMID:Molecular pathway of germ cell apoptosis following ischemia/reperfusion of the rat testis. 1105 53
Ischemia
/reperfusion (I/R) results in a robust induction of cyclooxygenase (COX)-2 in the newborn brain via unknown mechanisms, but glutamate release and activation of KA receptors may be involved. We examined effects of local KA (3-300 micromol/l for 10 min) treatment on cortical COX-2 expression in anesthetized piglets using a closed cranial window. Treated and corresponding control tissue samples were collected 0.5-10 h after treatment. COX-2 mRNA and protein levels were assessed using
RNase
protection assay and immunohistochemistry, respectively. KA elicited reproducible dose-dependent increases in cortical COX-2 mRNA unaffected by indomethacin or N(G)-nitro-L-arginine methyl ester pretreatment. COX-2 mRNA levels were elevated at 30 min, peaked at 2 h, but remained enhanced for up to 10 h after KA. Neuronal COX-2 immunoreactivity was also enhanced compared with the control side in all cortical layers 8h after KA. In summary, activation of KA receptors may be involved in the neuronal induction of COX-2 after I/R in the newborn.
...
PMID:Kainic acid rapidly induces cyclooxygenase (COX)-2 in piglet cerebral cortex. 1109 94
Aquaporins (AQPs) are a family of water-selective transporting proteins with homology to the major intrinsic protein (MIP) of lens [Cell 39 (1984) 49], that increase plasma membrane water permeability in secretory and absorptive cells. In the central nervous system (CNS), we detected the transcripts of AQP3, 5 and 8 in addition to the previously reported transcripts of AQP4 and 9 in astrocytes, of AQP3, 5 and 8 in neurons, of AQP8 in oligodendrocytes, and none of them in microglia using
RNase
protection assay and the reverse transcription-polymerase chain reaction (RT-PCR). Hypoxia evoked a marked decrease in the expression levels of AQP4, 5 and 9, but not of AQP3 and 8 mRNAs, and in astrocytes in vitro subsequent reoxygenation elicited the restoration of the expression of AQP4 and 9 to their basal levels. Interestingly, AQP5 showed a transient up-regulation (about 3-fold) and subsequent down-regulation of its expression within 20 h of reoxygenation after hypoxia. The changes in the profiles of AQP expression during hypoxia and reoxygenation were also observed by Western blot analysis. These results suggest that AQP5 may be one of the candidates for inducing the intracranial edema in the CNS after
ischemia
injury.
...
PMID:Alterations in the expression of the AQP family in cultured rat astrocytes during hypoxia and reoxygenation. 1137 53
Neuroserpin is an axonally secreted serine protease inhibitor expressed in the nervous system that protects neurons from
ischemia
-induced apoptosis. Mutant neuroserpin forms have been found polymerized in inclusion bodies in a familial autosomal encephalopathy causing dementia, or associated with epilepsy. Regulation of neuroserpin expression is mostly unknown. Here we demonstrate that neuroserpin mRNA and the RNA-binding protein HuD are co-expressed in the rat central nervous system, and that HuD binds neuroserpin mRNA in vitro with high affinity. Gel-shift, supershift and T1
RNase
assays revealed three HuD-binding sequences in the 3'-untranslated region (3'-UTR) of neuroserpin mRNA. They are AU-rich and 20, 51 and 19 nt in length. HuD binding to neuroserpin mRNA was also demonstrated in extracts of PC12 pheochromocytoma cells. Additionally, ectopic expression of increasing amounts of HuD in these cells results in the accumulation of neuroserpin 3'-UTR mRNA. Furthermore, stably transfected PC12 cells over-expressing HuD contain increased levels of both neuroserpin mRNAs (3.0 and 1.6 kb) and protein. Our results indicate that HuD stabilizes neuroserpin mRNA by binding to specific AU-rich sequences in its 3'-UTR, which prolongs the mRNA lifetime and increases protein level.
...
PMID:HuD binds to three AU-rich sequences in the 3'-UTR of neuroserpin mRNA and promotes the accumulation of neuroserpin mRNA and protein. 1200 Aug 40
Although kinins have been associated with the regulation of cardiovascular function in left ventricular hypertrophy (LVH) as a consequence of hypertension, myocardial infarction (MI), and/or diabetic cardiomyopathy, less is known about their receptor regulation under these conditions. We have therefore investigated the bradykinin B1-receptor (B1R) and B2-receptor (B2R) mRNA expression in rat models of MI, LVH and diabetes mellitus (DM). Sprague-Dawley rats (SD) were submitted to permanent ligation of the left descending coronary artery (LAD) to induce a MI, whereas DM was induced by a single injection of streptozotocin (STZ). LVH was induced after thoracic aortic banding (AB). Three weeks after MI, six weeks after STZ injection or six weeks after AB, left ventricular (LV) function was characterized using a Millar-tip catheter. Cardiac B1R- and B2R-mRNA expression were analyzed by specific
RNase
-protection assays (RPA). LV contractility (dP/dt max) was impaired by 40-48% in rats after induction of MI or DM compared to their controls. However, despite an enormous increase in LV end-diastolic pressure (LEVDP) to 310% after AB, LV contractility did not differ compared to the controls. These hemodynamic changes were accompanied by an up-regulation of cardiac B1R- (MI, 288%; STZ, 215%; AB, 4180%) and B2R-mRNA expression (MI, 122%; STZ, 288%; AB, 96%). Up-regulation of both BK-receptor (BKR) types in early stages of cardiac wound healing induced by
ischemia
and in chronic stages of cardiac remodeling induced by pressure-overload or by hyperglycemia indicates that kinins play a major role in the complex processes of cardiac tissue injury and repair.
...
PMID:Regulation of cardiac bradykinin B1- and B2-receptor mRNA in experimental ischemic, diabetic, and pressure-overload-induced cardiomyopathy. 1248 96
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