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

The tissue uptake of 3H-aprotinin was studied in anesthetized cats during acute myocardial ischemia (MI) 1 an 2 hr after injection of the tracer. Several tissues exhibited a rapid uptake of the protease inhibitor. Kidney, lung and liver demonstrated the greatest uptake with tissue/plasma ratios of 1.6 to 4.8. Spleen, adrenals, intestine, heart and pancreas exhibited tissue/plasma ratios of 0.28 to 0.58, whereas abdominal aorta, skeletal muscle and omentum had tissue/plasma ratios below 0.17. The rate of clearance of 3H-aprotinin from cat plasma was unaltered by myocardial ischemia. Although ischemic myocardial tissue took up less aprotinin than the non-ischemic myocardial tissue in the same hearts, ischemic tissue accumulated significant amounts of aprotinin relative to the non-ischemic region (82%). These data show that aprotinin reaches ischemic myocardial tissue during the first 2 hr of acute ischemia and would be available to antagonize some of the proteases which may be liberated during these critical early hours of the ischemic process.
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PMID:Tissue uptake of isotopically labeled aprotinin in early myocardial ischemia. 30 Jun 15

Because few HLA-DR-positive cells are present in the fetal spleen and liver, full HLA typing cannot be performed. However, B lymphocyte precursors can be transformed with Epstein-Barr virus to produce lymphoblastoid cells which express HLA-A, B, and DR antigens. Successful transformation was achieved, usually with spleen and liver, in nine fetuses aged from 15 to 18 weeks, mostly within 7 to 14 days of initiation of the cultures. Spleen-derived lymphoblasts were more suitable for typing because of their greater homogeneity and higher viability. Tissues from two 13-week fetuses from prostaglandin-induced abortions and from a spontaneously aborted 22-week fetus could not be transformed. This is probably attributable to prolonged ischemia before the tissues were obtained but, in the 13-week fetuses, absence of B lymphocyte precursors was not excluded. HLA-DR typing may be useful in obtaining well matched donor-recipient pairs in fetal pancreatic islet transplantation.
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PMID:HLA-DR typing of fetal human spleen and liver lymphoblastoid cells transformed by Epstein-Barr virus. 628 97

This study examined the neuroprotective effects and possible hepatotoxicity of (-)-epigallocatechin gallate (EGCG) in a rat model of transient focal cerebral ischemia. Male Sprague-Dawley rats (265-295 g) were treated with either 50 mg kg(-1) of EGCG or saline, i.p., immediately post-ischemia and every day thereafter, in a middle cerebral artery occlusion model of stroke. Sacrifice occurred 72 h post-ischemia and 2,3,5-triphenyltetrazolium chloride staining was used to quantify neuronal infarction. Hepatotoxicity was determined by taking blood samples for plasma alanine aminotransferase (ALT) activity. Spleen, kidney, liver and testes wet weights were also recorded. Total infarct volume was significantly (P<0.05) reduced in the EGCG-treated group as compared to controls. Analysis of the mean infarct area showed a significant (P<0.05) decrease in slices 6 and 7 in the EGCG-treated group. No significant differences were found in organ weights or ALT levels between treatment groups. Our findings, in part, validate and extend previous observations illustrating that 50 mg kg(-1), i.p. EGCG is non-toxic and neuroprotective. However, we also found that EGCG treatment appreciably increased (>50%) the number of animals that developed an intracerebral hemorrhage. We therefore conclude that 50 mg kg(-1) EGCG is not a viable intervention for the acute treatment of cerebral ischemia, as it is likely to increase the risk of intracerebral hemorrhaging.
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PMID:(-)-Epigallocatechin gallate as an intervention for the acute treatment of cerebral ischemia. 1592 95

Resveratrol is as an antioxidant with free radical-scavenging activity and finds its clinical application in the prevention of postischemic tissue injury following solid organ transplantation. This study investigates the effect of Resveratrol on spleen and ileum tissues subjected to hepatic ischemia-reperfusion (I/R) in rats. Twenty-four rats were recruited in the study as follows: group A: I/R (n = 8), group B: I/R + Resveratrol (n = 8), and group C: sham operation (n = 8). After intraperitonealy pretreatment of eight rats with resveratrol (15 mg/kg/d) for 5 days, 16 rats were subjected to 45 minutes of hepatic ischemia followed by 30 minutes reperfusion period. Resveratrol was given 15 minutes prior to ischemia and just before the reperfusion in rats. After reperfusion period all rats were sacrificed. Spleen and ileum tissues were examined spectrophotometrically to measure malondialdehyde (MDA), glutathione (GSH), and total nitrite, nitrate as an end product of nitric oxide (NO) levels. Concerning the spleen, statistically significant decrease of GSH and increase of MDA and NO levels were found group A when compared to groups B and C (P = .040, P = .004, and P = .001 group A vs group B; P = .05, P = .003, and P = .001 group A vs group C, respectively). Parallel results were obtained in ileum. A statistically significant decrease in GSH and an increase in MDA and NO levels in group A in respect to group B and group C was obtained (P = .048, P = .034, and P = .001 group A vs group B; P = .004, P = .001, and P = .003 group A vs group C, respectively). The result of this study shows that resveratrol has a protective effect on spleen and ileal mitochondrial oxidative stress in rats subjected to I/R.
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PMID:Protective effects of resveratrol on spleen and ileum in rats subjected to ischemia-reperfusion. 1654 24

This study was designed to track systemically administered mononuclear cells (MNCs) in the ischemic mouse brain using 7 T magnetic resonance imaging (MRI). Splenectomized wild-type mice were subjected to brain ischemia by 30 or 60 min filamentous occlusion of the middle cerebral artery (MCAo) and reperfusion. Spleen-derived MNCs were labeled with very small superparamagnetic iron-oxide particles (VSOP) and transfused into recipient mice 30 min, 8 h, or 24 h after MCAo via the tail vein. High-resolution MRI sequences were designed to monitor the dynamics of brain ischemia and to observe the migration and engraftment of transfused cells into the ischemic brain. T2*-weighted (gradient-echo) hypointense signal changes became apparent at 24-48 h after transfusion, were typically associated with the ischemic lesion border, and could be followed up to 5 weeks after the insult. Such presumed MNC-associated signal changes in MRI were confirmed by histochemical detection of iron (Prussian blue staining) and detection of constitutively expressed green fluorescent protein (GFP) in a subset of animals transfused with MNCs derived from GFP transgenic mice. Taken together, our results demonstrate that brain engraftment of systemically administered mononuclear cells can be visualized non-invasively over time and space using high-resolution MRI.
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PMID:Tracking of systemically administered mononuclear cells in the ischemic brain by high-field magnetic resonance imaging. 1697 81

Stroke induction in immunologically competent mice not only produces local ischemia and brain damage, but also induces early inflammatory changes in brain and peripheral immune responses. Although immune elements clearly are activated after brain vascular occlusion, the relative contribution of T and B lymphocytes to the developing lesion has not been quantified. We evaluated effects 22 h after middle cerebral artery occlusion (90 mins) on histologic injury and peripheral immune activation in severe combined immunodeficient (SCID) mice lacking T and B cells. Cortical and total infarct volumes were strikingly reduced in male SCID mice (n=14, 33+/-4% of contralateral cortex, n=10, 52+/-3% of contralateral hemisphere) versus immunologically intact C57BL/6 mice (wild type, n=9, 57+/-5% of contralateral cortex, 57+/-4% of contralateral hemisphere) (P<0.01). Striatal infarction was not altered (77+/-7% of contralateral striatum in SCID, 84+/-7% in wild type), suggesting that the core of the evolving ischemic lesion was not impacted by lack of T and B cells. As expected, inflammatory factors from immune cells in ischemic SCID brains were essentially absent, with the exception of interleukin-1beta increase in both SCID and wild type tissue. Spleen cell numbers were low in SCID mice, but were further reduced 22 h after stroke, with substantial reduction in most inflammatory factors except for increased expression of interferon-gamma and macrophage inflammatory protein (MIP)-2. These data quantify the damaging effect of T and B lymphocytes on early, evolving ischemic brain injury, and further implicate interleukin-1beta in brain and interferon-gamma and MIP-2 in spleen as inflammatory factors produced by cells other than T and B cells.
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PMID:T- and B-cell-deficient mice with experimental stroke have reduced lesion size and inflammation. 1739 92

ADP-ribosylation of cell surface proteins in mammalian cells is a post-translational modification by which ecto-ADP-ribosyltransferases (ARTs) transfer ADP-ribose from extracellular NAD to protein targets. The ART2 locus at murine chromosome 7 encompasses the tandem Art2a and Art2b genes that encode the distinct ART2.1 and ART2.2 proteins. Although both ecto-enzymes share 80% sequence identity, ART2.1 activity is uniquely regulated by an allosteric disulfide bond that is reducible in the presence of extracellular thiols, such as cysteine and glutathione, that accumulate in hypoxic and ischemic tissues. Previous studies have characterized the expression of ART2.1 and ART2.2 in murine T lymphocytes but not in other major classes of lymphoid and myeloid leukocytes. Here, we describe the expression of ART2.1 activity in a wide range of freshly isolated or tissue-cultured murine myeloid and lymphoid leukocytes. Spleen-derived macrophages, dendritic cells (DC), and B cells constitutively express ART2.1 as their predominant ART while spleen T cells express both ART2.1 and the thiol-independent ART2.2 isoform. Although bone-marrow-derived macrophages (BMDM) and dendritic cells (BMDC) constitutively express ART2.1 at low levels, it is markedly up-regulated when these cells are stimulated in vitro with IFNbeta or IFNgamma. ART2.1 expression and activity in splenic B cells is modestly up-regulated during incubation in vitro for 24 h, a condition that promotes B cell apoptosis. This increase in ART2.1 is attenuated by IL-4 (a B cell survival factor), but is not affected by IFNbeta/gamma, suggesting a possible induction of ART2.1 as an ancillary response to B cell apoptosis. In contrast, ART2.1 and ART2.2, which are highly expressed in freshly isolated splenic T cells, are markedly down-regulated when purified T cells are incubated in vitro for 12-24 h. Studies with the BW5147 mouse thymocyte line verified basal expression of ART2.1 and ART2.2, as in primary spleen T cells, and demonstrated that both isoforms can be up-regulated when T cells are maintained in the presence of IFNs. Comparison of the surface proteins which are ADP-ribosylated by ART2.1 in the different leukocyte subtypes indicated both shared and cell-specific proteins as ART2.1 substrates. The LFA-1 integrin, a major target for ART2.2 in T cells, is also ADP-ribosylated by the ART2.1 expressed in macrophages. Thus, ART2.1, in contrast to ART2.2, is expressed in a broad range of myeloid and lymphoid leukocytes. The thiol redox-sensitive nature of this ecto-enzyme suggests an involvement in purinergic signaling that occurs in the combined context of inflammation and hypoxia/ischemia.
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PMID:Basal and inducible expression of the thiol-sensitive ART2.1 ecto-ADP-ribosyltransferase in myeloid and lymphoid leukocytes. 1940 75

Cerebral ischemia, a phenomenon of reduction in cerebral blood flow, accounts for approximately 80% of all strokes, the third leading cause of death and the leading cause of adult disability. Cerebral ischemia causes heterogeneous changes in tissue oxygenation and cellular metabolism. Focal brain ischemia induces a profound and long-lasting inflammatory reaction which is dominated by macrophages derived from both resident microglia and circulating monocytic precursors. Bone marrow and spleen serve as a reservoir for hematopoietic progenitor cells, especially in rodents. Spleen-derived mononuclear cells home to the site of vascular injury and reduced neointima formation. The migration and engraftment of systematically administered spleen-derived mononuclear cells can be visualized in the post-ischemic brain. Therefore, we hypothesise that removal of the spleen may possibly decrease the production of mononuclear cells, and thus hinder or relieve the inflammatory reaction occured after cerebral ischemia/reperfusion injury. So, the splenectomy may be a prophylactic treatment method for cerebral ischemia.
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PMID:Splenectomy may be a prophylactic treatment for cerebral ischemia? 2038 Dec 61

Spleen pathology is rare in comparison with other abdominal organs, but often its lesions occur in complex pathological contexts, with systemic involvement. Although the lesions could be discretely symptomatic, their evolutionary potential might be severe. Conventional B-mode and Doppler ultrasound are the first-line imaging methods in spleen assessment, but frequently they do not allow the characterization of focal splenic abnormalities. Contrast-enhanced ultrasound (CEUS) is fast, safe, easy to perform, non-irradiating and can be used in patients with renal failure. By highlighting splenic macro and micro-vascularization, CEUS significantly increases the detection rate and allows the characterization of vascular (infarction, ischemia, thrombosis) and traumatic lesions, with high diagnostic accuracy. Additionally, ectopic splenic tissue can be identified with high accuracy. The method improves both the detection and characterization of splenic nodules, but some limitations still remain, especially in the differential diagnosis between malignant and some benign lesions. This article aims to portray aspects of CEUS imaging in various splenic pathologies using clinical examples from our experience and to review the CEUS contribution in the diagnosis of splenic lesions.
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PMID:Various aspects of Contrast-enhanced Ultrasonography in splenic lesions - a pictorial essay. 3289 7