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

To evaluate the mechanism of tolerance for ischemia, inductions of heat shock protein (HSP) 70 mRNA and immunoreactive HSP70 protein were studied in the preconditioned gerbil hippocampus. Following the single 3.5-min ischemia, HSP70 mRNA was induced in all hippocampal cells. However, the hippocampal CA1 cells produced only a minimum HSP70 protein, and the cells were almost lost by 7 days. Following the 3.5-min ischemia after 2-min pretreatment, the CA1 cells produced a strong immunoreactive HSP70 signal and large populations of the CA1 cells survived at 7 days. The peak time of the HSP70 mRNA induction shifted to earlier period of reperfusion in the CA1 cells as compared to the case with single ischemia. This accelerated change of HSP70 expression could play an important role for the acquisition of ischemic tolerance of the hippocampal CA1 neurons.
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PMID:The preconditioned hippocampus accelerates HSP70 heat shock gene expression following transient ischemia in the gerbil. 836 66

Induction of hsp70 heat shock protein (HSP70) and hsp70 mRNA was examined using adjacent sections in the same rat brain following permanent middle cerebral artery (MCA) occlusions, hsp70 mRNA was induced within 4 h of MCA occlusion and persisted for at least 24 h. Cellular resolution autoradiographs suggested that hsp70 mRNA was induced primarily in neurons in the periphery of ischemia both outside and inside of the infarction, with small amounts of hsp70 mRNA being induced in the core of the infarction. HSP70 protein was localized in neurons outside the infarction and in endothelial cells within the infarction at 24 h but not at 4 h following permanent MCA occlusions. It is proposed that the penumbra, one of the areas that can be rescued by pharmacological agents, can be defined anatomically as the volume of tissue outside the area of infarction in which HSP70 protein is expressed primarily in neurons.
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PMID:Induction of heat shock hsp70 mRNA and HSP70 kDa protein in neurons in the 'penumbra' following focal cerebral ischemia in the rat. 837 89

Hippocampal CA1 neurons are the most vulnerable to transient cerebral ischemia. However, the mechanism has not been fully understood. The level of mRNA for cytochrome C oxidase (COX) subunit I (COX-I), which is encoded by mitochondrial (mt) DNA, progressively decreased in the hippocampal CA1 neurons of gerbils from 3 h of reperfusion after 3.5 min of transient forebrain ischemia and completely disappeared at 7 days. The activity of COX protein also showed an early decrease in CA1 cells and was followed by reduction of the level of COX-I DNA after 2 days. However, succinic dehydrogenase, an mt enzyme encoded by nuclear DNA, maintained normal activity until 1 day in the CA1 cells and significantly decreased at 7 days. The mRNA for mt heat shock protein (HSP) 60 began to increase at 3 h in the CA1 cells and was sustained until 1 day. The mRNAs for 72-kDa heat shock protein and 73-kDa heat shock cognate protein, which are located mainly in the cytoplasm, were induced together in the CA1 cells with a peak at 1-2 days. These results suggest that a disturbance of mt DNA expression occurred in the CA1 neurons at the early stage of reperfusion and was aggravated over the course of time. The disturbance could cause progressive failure of energy production of the cells that eventually results in neuronal cell death.
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PMID:Changes of mitochondrial DNA and heat shock protein gene expressions in gerbil hippocampus after transient forebrain ischemia. 839 36

Stressful stimuli such as heat, oxidative stress, heavy metals, and tissue trauma induce the expression of a family of proteins commonly referred to as stress proteins or heat shock proteins. The functions of these proteins are varied but include glycolysis, antioxidant defense, and several postulated "chaperone" functions involving the folding, unfolding, and translocation of other proteins. Heme oxygenase, the enzyme that catalyzes the degradation of heme to biliverdin, is also heat inducible and is, therefore, a heat shock protein. In the kidney, ischemia has been observed by several investigators to induce expression of the more commonly studied heat shock proteins HSP 70 and HSP 72. In addition, exposure of the kidney to myoglobin after glycerol injection induced heme oxygenase. The purpose of this study was to determine whether heme oxygenase is expressed as a stress protein after renal ischemia. Renal ischemia was induced in rats after right nephrectomy by clamping the renal artery for 40 minutes. Gene expression was evaluated after 60 minutes to 96 hours of postischemic reperfusion. There was essentially no expression of heme oxygenase at any of the time points evaluated. The absence of heme oxygenase expression was in striking contrast to the prompt and dramatic expression of HSP 70. This finding is consistent with the concept that all "stress proteins" are not equivalent and that, although there is considerable overlap between heat-sensitive gene promoters and oxidant stress-sensitive gene promoters, there is specificity for the type of stimulus that is able to activate any given stress protein gene.
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PMID:Heme oxygenase is not expressed as a stress protein after renal ischemia. 840 10

Induction of the 70-kDa heat shock protein (HSP70) was demonstrated immunocytochemically in adult rats 4 h to 7 days following temporary middle cerebral artery (MCA) occlusions lasting 30, 60, or 90 min. Maximal HSP70 induction occurred approximately 24 h following ischemia. Thirty minutes of ischemia induced HSP70 in neurons throughout the cortex in the MCA distribution, whereas 90 min of ischemia induced HSP70 in neurons in the penumbra. HSP70 protein was induced in endothelial cells in infarcted neocortex following 60-90 min of MCA occlusion, and HSP70 was induced in endothelial cells in infarcted regions of lateral striatum following 30-90 min of MCA occlusion. hsp70 mRNA was induced in the MCA distribution in cortex and to a lesser extent in striatum at 2 h to 3 days following 60 min of ischemia. It is proposed that brief ischemia induces hsp70 mRNA and HSP70 protein in the cells most vulnerable to ischemia--the neurons. HSP70 protein is not induced in most neurons and glia following 60-90 min of ischemia in areas destined to infarct, whereas it is induced in vascular endothelial cells.
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PMID:Induction of 70-kDa heat shock protein and hsp70 mRNA following transient focal cerebral ischemia in the rat. 841 99

Distributions of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNAs after 2, 5 and 15 min of transient global ischemia in gerbil forebrain were investigated by in situ hybridization using cloned cDNA probes selective for each mRNA species. Morphological studies were also performed at the dorsal hippocampal level of coronal sections from the identical brains until 7 days after the reperfusion. Following 2 min of ischemia, HSP70 and HSC70 mRNAs were induced together in hippocampal dentate granule cells at 1 and 3 h of the reperfusion. No histological change was observed in brain cells. Following 5 min of ischemia, HSP70 and HSC70 mRNAs were induced in all hippocampal cells. The induction of HSP70 mRNA in hippocampal CA1 cells sustained until 2 days, while that of HSC70 mRNA declined gradually. Only CA1 cells were lost at 7 days of the reperfusion. Following 15 min of ischemia, the mRNAs were induced in more extensive brain regions including neocortex and thalamic nuclei. In hippocampal CA1 cells, inductions of HSP70 and HSC70 mRNAs diminished by 2 days corresponding with the neuronal damage. HSC70 mRNA induction was not so much as HSP70 mRNA induction especially in hippocampal CA1 and thalamic cells. Our results showed that HSP70 and HSC70 mRNAs were generally induced together after transient ischemia, but that the inductions were spatially and chronologically different after different periods of ischemia. The dissociation of the induction was also found in cells severely injured after 5 and 15 min of ischemia.
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PMID:Temporal profile of the induction of heat shock protein 70 and heat shock cognate protein 70 mRNAs after transient ischemia in gerbil brain. 843 64

We investigated the correlation between protection against ischemic neuronal damage by preconditioning with sublethal ischemia and the expression of heat shock protein-70 (HSP70). Three minutes of forebrain ischemia in the rat induced by four-vessel occlusion and 3 days of reperfusion was followed by 6, 8, and 10 minutes of ischemia. Seven days after the second ischemia, the brains were used for histology. Two hours, 1, 3, and 7 days after 3 or 6 minutes of ischemia, the brains were used for immunohistochemistry with an antibody raised against HSP70. Three minutes of ischemia produced no neuronal damage in the hippocampus. Six, 8, and 10 minutes of ischemia produced severe neuronal damage to CA1. However, CA1 neurons were preserved in animals subjected to 6 and 8 minutes of ischemia following preconditioning with 3 minutes of ischemia. Immunostaining showed that HSP70 was induced in the CA1 subfield 3 days after 3 minutes of ischemia. HSP70 was stained in the CA1, CA3, and CA4 subfields 1 and 3 days after 6 minutes of ischemia with or without preconditioning. However, HSP70 was also stained in CA1 2 hours and 7 days after 6 minutes of ischemia following preconditioning. These results strongly suggest that stress response induced by sublethal ischemia protects against ischemic neuronal damage. However, the protection was not seen when HSP70 synthesis was delayed. Presence of HSP70 during and immediately after ischemia may be critical for the protection against ischemic neuronal damage following preconditioning.
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PMID:[Correlation between induction of ischemic tolerance and expression of heat shock protein-70 in the rat hippocampus]. 847 66

The effect of pentobarbital on the induction of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNAs after transient global ischemia in gerbil brains was investigated by in situ hybridization using cloned cDNA probes selective for each mRNA species. In sham control brains, HSP70 mRNA was scarcely present, whereas HSC70 mRNA was present in most cell populations. After a 5-min occlusion of bilateral common carotid arteries, HSP70 and HSC70 mRNAs were induced together in several cells and were especially dense in hippocampal dentate granule cells at 3 h, but the strong hybridization of the mRNAs continued only in hippocampal CA1 cells by 2 days. At 7 days after the ischemia, CA1 neuronal cell death was apparent, and the HSP70 mRNA disappeared and HSC70 mRNA content returned to the sham level, except for in the CA1 cells. Pretreatment with pentobarbital (40 mg/kg, i.p.) greatly reduced or inhibited the induction of HSP70 and HSC70 mRNAs at both early (3-h) and late (2-day) phases after ischemia. The drug also prevented CA1 cell death at 7 days along with the maintenance of expression of HSC70 mRNA at the sham control level. Hypothermic effects of pentobarbital were noted at 30 and 60 min after the reperfusion, whereas at 2 h there was no statistical significance between the control and drug-treated groups. The great reduction of HSP70 and HSC70 mRNA induction at both early and late phases after ischemia suggests that pentobarbital reduces intra-and/or postischemic stress and may protect CA1 cells from ischemic damage.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reduction of HSP70 and HSC70 heat shock mRNA induction by pentobarbital after transient global ischemia in gerbil brain. 851 71

A protective effect of bifemelane hydrochloride (BF) on hippocampal CA1 neuronal death in gerbils was investigated following transient forebrain ischemia in relation to the induction of 70-kd heat shock protein (HSP70) and its mRNA. Histological examination showed that the neuronal density of the hippocampal CA1 sector treated with 10 and 30 mg/kg of BF (i.p.) was higher than that of the vehicle (p < 0.05 and p < 0.01, respectively) at 7 days after ischemia. Immunohistochemistry against HSP70 protein and in situ hybridization for the mRNA revealed that the inductions of immunoreactive HSP70 and the mRNA were remarkably reduced and limited in the brain hippocampi treated with BF (30 mg/kg) as compared with vehicle-treated animals. These data indicate that BF possesses a protective effect against ischemic injury to the vulnerable CA1 neurons. The possible mechanisms of the protection are discussed.
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PMID:Protective effect of bifemelane hydrochloride on ischemic hippocampal CA1 neuronal damage in the gerbil: relation to induction of HSP70. 851 88

Glucose transport into nonneuronal brain cells uses differently glycosylated forms of the glucose transport protein, GLUT1. Microvascular GLUT1 is readily seen on immunocytochemistry, although its parenchymal localization has been difficult. Following ischemia, GLUT1 mRNA increases, but whether GLUT1 protein also changes is uncertain. Therefore, we examined the immunocytochemical distribution of GLUT1 in normal rat brain and after transient global forebrain ischemia. A novel immunocytochemical finding was peptide-inhibitable GLUT1 immunoreactive staining in parenchyma as well as in cerebral microvessels. In nonischemic rats, parenchymal GLUT1 staining co-localizes with glial fibrillary acidic protein (GFAP) in perivascular foot processes of astrocytes. By 24 h after ischemia, both microvascular and nonmicrovascular GLUT1 immunoreactivity increased widely, persisting at 4 days postischemia. Vascularity within sections of brain similarly increased after ischemia. Increased parenchymal GLUT1 expression was paralleled by staining for GFAP, suggesting that nonvascular GLUT1 overexpression may occur in reactive astrocytes. A final observation was a rapid expression of inducible heat shock protein (HSP)70 in hippocampus and cortex by 24 h after ischemia. We conclude that GLUT1 is normally immunocytochemically detectable in cerebral microvessels and parenchyma and that parenchymal expression occurs in some astroglia. After global cerebral ischemia, GLUT1 overexpression occurs rapidly and widely in microvessels and parenchyma; its overexpression may be related to an immediate early-gene form of response to cellular stress.
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PMID:Forebrain ischemia increases GLUT1 protein in brain microvessels and parenchyma. 853 May 57


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