Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Young and old (4 and 25 months of age, respectively) Fisher 344/Brown Norway hybrid female rats were subjected to four 3 min episodes of ischemia separated by 5 min of reperfusion. Corresponding open-chest sham-operated groups received 32 min of no intervention. All rats were allowed to recover, and 24h later hearts were removed and frozen in liquid nitrogen. Global gene profiling in the ischemic and the non-ischemic areas and in the sham-operated hearts as well was carried out by using Affymetrix Gene Chips. Young ischemic hearts demonstrated down-regulation of gene expression associated with early-remodeling including down-regulation of tissue inhibitor of metalloproteinase 1, decorin, collagen, tropoelastin, and fibulin, as well as decreases in hypertrophy-related transcripts. In contrast, old hearts showed a unique injury-related response, which included up-regulation of mRNAs for proteins associated with hypertrophy or apoptosis (including H36-alpha7 integrin, alpha-actin, tubulin, filamin, connective tissue growth factor, calcineurin, serine protease, and apoptosis inducing factor). These injury-related changes in gene expression could in part explain increased gravity of outcomes of ischemia and myocardial infarction in elderly hearts.
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PMID:Age-related changes of cardiac gene expression following myocardial ischemia/reperfusion. 1465 66

Apoptosis has been associated with several events in solid organ transplantation, including ischemia/reperfusion (IR) injury and acute rejection. To determine whether apoptosis-profiles may distinguish these two conditions, we analyzed apoptosis rates in a rat orthotopic small bowel transplant (SBT) model. SBT was performed in Lewis rats with either freshly harvested or preserved (4 h, in UW at 4 degrees C) syngeneic and allogeneic (Brown-Norway) grafts. Bowel samples were collected 2 h after reperfusion and on small bowel transplant postoperative days (POD) 1, 4, and 7. Apoptosis was detected by measuring levels of histone-associated DNA fragments and caspase 3 expression, and by determining apoptotic body counts. All markers measured 2 h after reperfusion increased profoundly in association with preservation. After a significant decrease on POD 1, apoptosis rates rose again between POD 4 and 7 only in allogeneic grafts. This distinct second increase in apoptosis may be an early and specific sign of acute rejection.
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PMID:Increased apoptosis is specific for acute rejection in rat small bowel transplant. 1512 82

Ischemia-reperfusion injury is a dominant factor limiting tissue survival in any microsurgical tissue transplantation, a fact that also applies to allogeneic hand transplantation. The clinical experience of the 12 human hand transplantations indicates that shorter ischemia times result in reduced tissue damage and, ultimately, in better hand function. Heat stress preconditioning and the accompanying up-regulation of the heat shock protein 72 have been shown to reduce the ischemia-reperfusion injury following ischemia of various organs, including organ transplantation. The aim of this study was to reduce the ischemia-reperfusion injury in a model of composite tissue allotransplantation. Allogeneic hind limb transplantations were performed from Lewis (donor) to Brown-Norway rats. Donor rats in group A (n = 10) received a prior heat shock whereas rats in group B (n = 10) did not receive any prior heat shock. Group C served as a control group without transplantation. The transplantations were performed 24 hours after the heat shock, at which time the heat shock protein 72 was shown to be up-regulated. The outcome was evaluated 24 hours after transplantation by nitroblue tetrazolium staining and wet-to-dry weight ratio of muscle slices (anterior tibial muscle). The nitroblue tetrazolium staining showed a significant reduction of necrotic muscle in group A (prior heat shock) (p = 0.005). The wet-to-dry ratio was significantly reduced in group A (prior heat shock), indicating less muscle edema and less tissue damage (p = 0.05). Heat shock preconditioning 24 hours before an ischemic event leads to an up-regulation of heat shock protein 72 in muscle and to a tissue protection reducing ischemia-reperfusion injury in composite tissue transplantation.
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PMID:Reduction of skeletal muscle injury in composite tissue allotransplantation by heat stress preconditioning. 1557 55

Hearts from Brown Norway (BN/Mcw) rats are more resistant to ischemia than hearts from Dahl S (SS/Mcw) rats. We determined whether nitric oxide (.NO) is responsible for increased cardioprotection in BN/Mcw vs. SS/Mcw hearts. Hearts from the two strains were treated with N(G)-monomethyl-L-arginine (L-NMA) or S-nitrosoglutathione (GSNO) before ischemia and reperfusion. Infarct size in untreated BN/Mcw hearts was approximately 63% less than in SS/Mcw hearts. Inhibiting NOS with L-NMA increased infarct size in BN/Mcw hearts to that observed in untreated SS/Mcw hearts but did not further increase injury in SS/Mcw hearts. The .NO donor GSNO decreased infarct size in SS/Mcw rats but had no effect on BN/Mcw hearts. Plasma and heart tissue from BN/Mcw rats contained 80% and 130% more nitrite + nitrate than that from SS/Mcw rats. These data suggest that increased .NO production protects BN/Mcw hearts from ischemic injury. Real time PCR showed no differences in NOS1, NOS2 or NOS3 isozyme transcripts in the hearts from the two strains. NOS3 was the only isozyme detected by western analysis. Both strains exhibited the same level of NOS3 and hsp90 protein expression. However, hsp90 association with NOS3 in BN/Mcw hearts was increased twofold compared with SS/Mcw hearts. Inhibiting hsp90-NOS3 interaction with geldanamycin decreased the resistance to ischemia in BN/Mcw hearts but not in SS/Mcw hearts. SS/Mcw hearts also generated three times more N(omega)-nitro-L-arginine-methylester inhibitable superoxide than BN/Mcw hearts. These findings indicate that hsp90 with NOS3 increases .NO production and decreases uncoupled NOS3 activity. We conclude increased association of hsp90 with NOS3 is a major mechanism by which BN/Mcw hearts are more resistant to ischemia than SS/Mcw hearts.
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PMID:Increased resistance to myocardial ischemia in the Brown Norway vs. Dahl S rat: role of nitric oxide synthase and Hsp90. 1580 39

In this study, the authors explored the feasibility of transplanting a "pectoral skin flap" as an alternative model for composite skin allotransplantation research. Genetically inbred male Lewis rats (LEW; RT1l) (n = 13), weighing 250 to 300 gr, were used as recipients and Brown Norway rats (BN; RT1n) (n = 8) rats were used as donors. Five Brown Norway rats had bilateral and three had unilateral flap harvest with a total of 13 flap transplantations to Lewis rats. All flaps were transplanted to the groin regions of the recipients and microsurgical anastomoses with 10-0 nylon were performed between the axillary vessels of the flaps and the femoral vessels of the recipient animals. The mean operation time was 55 min, with an ischemia time of 25 min. All transplantations were successful immediately postoperatively. The recipient animals were treated with Cyclosporine A (16 mg/kg/day) from the day of the surgery for 1 week, and then discontinued. One flap developed infection at postoperative day 11 and one flap had partial (50 percent) necrosis. The early signs of rejection started 8 to 9 days after the cessation of the immunosuppressive treatment, and all flaps were acutely and uniformly rejected within 3 to 4 days. The feasibility of harvesting two flaps from one donor animal allowed saving donor animal lives and reducing donor-specific variables.
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PMID:Pectoral skin flap as a reliable and simple model for vascularized composite skin transplantation research. 1588 Feb 98

A nonfunctional heterotopic hindlimb allotransplantation model is presented, and a study was performed between this model and standard orthotopic hindlimb transplantation to compare operation and ischemia time, overall morbidity, and mortality rates. In this model, the skin component of the hindlimb was stripped away to the ankle level, and the remaining part along with the vascularized epigastric skin was transplanted heterotopically to the inguinal space of the recipient. No osteotomy and intramedullary fixation were performed. Thirty heterotopic and orthotopic hindlimb transplantations were performed in two groups. Each group involved 15 transplantations from inbred, male Brown Norway (BN; RT1n) weighing 150-200 g to Lewis rats (LEW; RT1(1)) weighing 250-300 g. The animals were followed up for 2 weeks under immunosuppression with cyclosporine A (16 mg/kg/day). Mean operation times for heterotopic and orthotopic hindlimb transplantations were 60 and 105 min, with ischemia times of 35 and 85 min, respectively. No animal deaths or major complications were encountered in heterotopic hindlimb transplantation during the follow-up period. Seroma formation was observed in one animal as the only minor complication. The mortality rate for orthotopic hindlimb transplantation was 26.7%, and there were minor complications in 35%, including infection, ulceration, and loss of rigid fixation. This model circumvents the disadvantages of osteotomy and intramedullary fixation, which may increase the risk of blood loss, embolus, and infection in immunosuppressed animals. It also helps avoid tension or kinking on the anastomosis due to inadequate judgment of the osteotomy level, distortion associated with loss of rigid fixation, and weight mismatch between donor and recipient. From the immunological point of view, insult to bone marrow is avoided, and a relatively constant amount of bone marrow is introduced to be used in chimerism-based tolerance studies. We recommend this model for composite-tissue allotransplantation studies when functional recovery is not of primary importance.
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PMID:Heterotopic hindlimb allotransplantation in rats: an alternative model for immunological research in composite-tissue allotransplantation. 1603 37

The aim of the study was to characterize the role of cold ischemia in the process of acute rejection using an experimental renal transplant model. Syngeneic renal transplants were performed between Wistar Agouti rats and allogeneic grafts using Wistar-Agouti rats as recipients of Brown-Norway kidneys. For cold ischemia (CI), kidneys were preserved in Euro-Collins (4 degrees C/ 2.5 hours). Rats were bilaterally nephrectomized at the moment of renal transplant and did not receive any immunosuppressant. The groups were NoAR (n = 6): immediate syngeneic transplant; CI-NoAR (n = 6): syngeneic transplant with CI; AR (n = 13): immediate allogeneic graft; CI-AR (n = 6): allogeneic graft with CI. Allogeneic rats were followed for the survival study. Syngeneic rats, with mean survival time beyond 6 months, were sacrificed on the day 7 to compare grafts with those in the allogeneic groups. H&E- and PAS-stained grafts were evaluated using the Banff criteria. Tissue INF-gamma and TNF-alpha were quantified by RT-real time-PCR on the kidney grafts. Renal insufficiency did not appear in the NoAR group, but it did from the posttransplant day 5 in both acute rejection groups. While NoAR kidneys showed well-conserved renal architecture, then AR group displayed variable degrees of tubular necrosis with scarce cellular infiltration, interstitial hemorrhage, vascular damage with fibrinoid necrosis, perivascular edema, and nuclear disruption. Cold ischemia in rejecting animals increased the mortality rate due to renal insufficiency and accelerated acute rejection. Independently of CI, the proinflammatory cytokines TNF-alpha and INF-gamma were increased in both rejection groups. In conclusion, addition of CI overactivates the acute rejection process via a humoral component.
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PMID:Role of cold ischemia in acute rejection: characterization of a humoral-like acute rejection in experimental renal transplantation. 1638 14

Chemokines activate and recruit specific leukocyte subpopulations. We sought to determine whether neutrophil migration, which can contribute to the development of ischemia-reperfusion injury, correlates with lung allograft rejection. Orthotopic left lung allotransplantation was performed from Brown Norway (donor) to Fisher 344 (recipient) rats. Because the role of activated neutrophils in the development of allograft rejection is believed to be biphasic, we used specific CXC receptor inhibition with antileukinate in 2 dosing regimens. Recipients were allocated into 4 groups; A (early administration) received 2 doses of antileukinate (10.0 mg/kg) intramuscularly 24 h before and immediately after transplantation; B (continuous administration) continuously received antileukinate intraperitoneally (10.0 mg/kg/day) for 7 days after surgery. Groups A or B were compared with individual controls that received PBS alone. The progression of rejection was assessed radiographically. Histologic evaluation of allograft rejection based on pathologic rejection grade, performed on day 7, demonstrated significantly lower histologic rejection in group B compared with the control group (2.1+/-1.0 vs. 3.3+/-0.5; P=0.018), whereas there was no significant difference in group A compared with the control group. There were no significant differences between the aeration scores of groups A or B compared with their control groups. Our data suggest that neutrophils may play a promoting role in the development of allograft rejection, and blockage of neutrophil migration may suppress acute lung allograft rejection.
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PMID:Prevention of neutrophil migration ameliorates rat lung allograft rejection. 1722 68

Old age is associated with an enhanced susceptibility to stroke and poor recovery from brain injury, but the cellular mechanisms underlying such phenomena are not known. Using BrdU-labeling, quantitative immunohistochemistry and 3D-reconstruction of confocal images in a rat model of mild cerebral ischemia, we found that aged rats are highly susceptible to develop an early infarct that is associated with premature cellular proliferation originating from the vascular tree. In aged rats we also found a rapid delimitation of the infarct area by capillary-derived neuroepithelial cells and an early incorporation of these cells into the glial scar. Since most proliferating cells at the infarct site are microglia or nestin-positive cells derived from the vascular wall, we conclude that the vasculature plays a hitherto unrecognized role as a source of proliferating neuroepithelial cells after stroke. Age-associated alterations in the timing and origin of the cytogenic response to cerebral ischemia may underlie the poor functional recovery from stroke. Clarifying the molecular basis of these phenomena could yield novel approaches to enhancing neurorestoration in the elderly. Studies of stroke in experimental animals have demonstrated the neuroprotective efficacy of a variety of interventions, but most of the strategies that have been clinically tested failed to show benefit in aged humans. One possible explanation for this discrepancy between laboratory and clinical investigations is the role that age plays in the recovery of the brain from insult. Although it is well known that aging is a risk factor for stroke (Barnett HJ, 2002), the majority of experimental studies of stroke have been performed on young animals, and therefore may not fully replicate the effects of ischemia on neural tissue in aged subjects (Wang LC et al., 1995; Davies M et al., 1995; Sutherland GR et al., 1996; Popa-Wagner A et al., 1998, 1999a). Hence, the aged post-acute animal model is clinically most relevant to stroke rehabilitation and cellular studies (Lindner MD et al., 2003; Brown AW et al., 2003; Badan I et al., 2003).
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PMID:Premature cellular proliferation following cortical infarct in aged rats. 1730 79

Vascular endothelial growth factor (VEGF) is a potent inflammation, vascular permeability, and angiogenic factor. Variations of the VEGF gene are implicated in the pathogenesis of diabetic retinopathy. Previous studies have shown that Brown Norway (BN) rats have higher retinal VEGF levels and more severe retinal vascular leakage than Sprague-Dawley (SD) rats in response to ischemia and diabetes. To investigate the molecular mechanism of vascular leakage in this animal model, F2 progeny were generated by crossbreeding BN and SD rats. Neonatal rats were exposed to hyperoxia to induce oxygen-induced retinopathy (OIR) models. The F2 rats in response to ischemia have shown a linear distribution of retinal VEGF levels, which is significantly and positively correlated to retinal vascular leakage. We identified a single nucleotide polymorphism (SNP) at upstream stimulating factor-binding site in the VEGF promoter region between BN and SD rats. No differences were found in retinal vascular permeability or VEGF levels between F2 rats with BN, SD, and BN/SD alleles of VEGF SNP. The increased retinal VEGF levels are correlated to ischemia-induced retinal vascular leakage in the OIR rat model. The VEGF mRNA and promoter are not responsible for increased retinal VEGF level and vascular permeability. The up-regulation of VEGF expression activated by a yet to be identified upstream factor or mediator affecting VEGF stability may be associated with a high susceptibility to retinal vascular leakage in BN rats.
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PMID:Rat strain-dependent susceptibility to ischemia-induced retinopathy associated with retinal vascular endothelial growth factor regulation. 1744 32


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