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Activation States (activation + states)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Platelet hyperactivity in clinical depression and the beneficial effect of antidepressant drug treatment: how strong is the evidence?

ACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2004
R. Von Känel
Objective:, Platelet hyperactivity is thought to contribute to the increased coronary artery disease (CAD) risk in depression. This study reviewed the evidence for hyperactive platelets and for effects of antidepressant drug treatment on platelet ,stickiness' in clinical depression. Method:, By means of PubMed electronic library search, 34 studies in English were identified (1983,2003) and critically reviewed. Results:, In depression, flow cytometry studies allowing detection of subtle platelet activation states consistently found at least one platelet activation marker to be increased, while the bulk of platelet aggregation studies did not suggest increased platelet aggregability. Platelets seem to be more activated in depressed patients with CAD than in depressed individuals without CAD. The selective serotonin reuptake inhibitors normalized platelet hyperactivity in four studies. Conclusion:, Data on platelet activity in depression are inconclusive. To resolve this issue and its clinical implications, studies in larger sample sizes controlling for confounders of platelet functioning and prospectively designed are needed. [source]

Protective effects of naloxone in two-hit seizure model

EPILEPSIA, Issue 3 2010
Lu Yang
Summary Purpose:, Early life status epilepticus (SE) could enhance the vulnerability of the immature brain to a second SE in adulthood (two-hit seizure model). Naloxone has been proved to possess inflammation inhibitory effects in nervous system. This study was designed to evaluate the dose-dependent protective effects of naloxone in kainic acid (KA),induced two-hit seizure model. Methods:, After KA-induced SE at postnatal day 15 (P15), Sprague-Dawley rats were infused with either saline or different doses (1.92, 3.84, 5.76, and 7.68 mg/kg) of naloxone continuously for 12 h. De novo synthesis of cytokines (interleukin-1, [IL-1,], S100B) was assessed by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) at 12 h after P15 SE. Glial activation states were analyzed by western blotting of glial markers (glial fibrillary acidic protein [GFAP], S100B, Iba1) both at 12 h after P15 SE and at P45. After a second SE at P45, cognitive deteriorations were evaluated by Morris water tests and neuron injuries were evaluated by TdT-mediated dUTP nick end labeling (TUNEL) assays. Results:, Naloxone reduced IL-1, synthesis and microglial activation most potently at a dose of 3.84 mg/kg. Attenuation of S100B synthesis and astrocyte activation were achieved most dramatically by naloxone at a dose of 5.76 mg/kg, which is equal to the most powerful dose in ameliorating cognitive injuries and neuron apoptosis after second SE. Conclusions:, Naloxone treatment immediately after early life SE could dose-dependently reduce cytokine production, glial activation, and further lower the vulnerability of immature brains to a second hit in adulthood. [source]

Ligand binding of leukocyte integrin very late antigen-4 involves exposure of sulfhydryl groups and is subject to redox modulation

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2008
Si-Yen Liu
Abstract Activation of leukocyte integrins is important for selective recruitment of cells from the circulation to tissues. Our previous studies showed that the binding between the integrin very late antigen-4 (VLA-4) and vascular cell adhesion molecule-1 (VCAM-1) is modulated by reactive oxygen species. In this study, we investigated the molecular nature of redox modulation on the activation states of VLA-4 on human leukocytes. We found that ligand binding of VLA-4 induced exposure of sulfhydryl groups on the ,4 peptide. Low concentrations (5,10,µM) of exogenous hydrogen peroxide in the presence or absence of added glutathione enhanced the ligand binding ability of VLA-4 to VCAM-1 and cell rolling on VCAM-1, while higher concentrations (,100,µM) of hydrogen peroxide inhibited the binding. Exogenous hydrogen peroxide and glutathione induced molecular modification of S -glutathionylation on the ,4 peptide. The redox regulation of the VLA-4 binding activity required outside-in signaling and cytoskeleton rearrangement. Our results indicate that ligand binding of VLA-4 involves redox modulations which may play a pivotal role in regulating the activation states of VLA-4 in inflammatory tissues and hence direct leukocyte trafficking. [source]

Preoperative Functional Assessment of Auditory Cortex in Adult Cochlear Implant Users,,

THE LARYNGOSCOPE, Issue 1 2001
Peter S. Roland MD
Abstract Objectives To e-plore functional neuroanatomical responses to auditory stimulation before and after implantation. Study Design A prospective study of three cochlear implant candidates (pure-tone averages of 90 dB HL or greater bilaterally and hearing in noise test [HINT] performances of <40%) in which regional cerebral blood flow (rCBF) was assessed using single photon emission computed tomography (SPECT). Methods Candidates watched a 15-minute videotaped story under four conditions: audio presented monaurally in the right and left ears (aided), audio presented binaurally (aided), and visual-only presentation of the story. Five minutes into each story, 20 to 25 mCi of technetium 99m (99mTc) hexamethyl-propyleneamine-oxime (HMPAO) (Ceratec; Nycomed Amersham, Princeton, NJ, U.S.A.) was injected over a 30-second period to ensure that subjects were unaware of tracer administration. Subjects were scanned for 20 minutes using a PRISM 3000 gamma camera (Picker International, Cleveland, OH, U.S.A.). Data were normalized and co-registered, and subtraction images were compiled. Subtraction images contrasted activation patterns generated under the visual-only control condition to the auditory activation states acquired monaurally and binaurally. Results Right and left ear monaural stimulation in normal hearing subjects resulted in significant bilateral activation of Brodmann areas 41, 42, 21, 22, and 38. Although substantial intersubject response variability was noted, subjects generally failed to bilaterally activate these areas under monaural hearing aid presentations; however, bilateral activation of areas 41 and 22 was noted under binaural presentations. Conclusions Despite relatively similar hearing losses in each ear, significant differences in preoperative auditory corte- activation were observed between ears. These data suggest that functional brain imaging provides a useful tool for e-ploring the responsiveness of the auditory corte- in cochlear implant candidates. [source]

Alternative Macrophage Activation-Associated Transcripts in T-Cell-Mediated Rejection of Mouse Kidney Allografts

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2010
K. S. Famulski
Macrophages display two activation states that are considered mutually exclusive: classical macrophage activation (CMA), inducible by IFNG, and alternative macrophage activation (AMA), inducible by IL4 and IL13. CMA is prominent in allograft rejection and AMA is associated with tissue remodeling after injury. We studied expression of AMA markers in mouse kidney allografts and in kidneys with acute tubular necrosis (ATN). In rejecting allografts, unlike interferon gamma (IFNG) effects and T-cell infiltration that developed rapidly and plateaued by day 7, AMA transcripts (Arg1, Mrc1, Mmp12 and Ear1) rose progressively as tubulitis and parenchymal deterioration developed at days 21 and 42, despite persistent IFNG effects. AMA in allografts was associated with transcripts for AMA inducers IL4, IL13 and inhibin A, but also occurred when hosts lacked IL4/IL13 receptors, suggesting a role for inhibin A. Kidneys with ATN injured by ischemia/reperfusion also had increased expression of AMA markers and inhibin A. Thus kidneys undergoing T-cell-mediated rejection progressively acquire macrophages with alternative activation phenotype despite strong local IFNG effects, independent of IL4 and IL13. Although the mechanisms and causal relationships remain to be determined, high AMA transcript levels in rejecting allografts are strongly associated with and may be a consequence of parenchymal deterioration similar to ATN. [source]