768 research outputs found
Conceptual and Practical Issues in the Pharmacological Treatment of Brain Injury
It is only within the last ten years that
research on treatment for central nervous
system (CNS) recovery after injury has become
more focused on the complexities involved in
promoting recovery from brain injury when the
CNS is viewed as an integrated and dynamic
system. There have been major advances in
research in recovery over the last decade,
including new information on the mechanics
and genetics of metabolism and chemical
activity, the definition of excitotoxic effects and
the discovery that the brain itself secretes
complex proteins, peptides and hormones which
are capable of directly stimulating the repair of
damaged neurons or blocking some of the
degenerative processes caused by the injury
cascade. Many of these agents, plus other nontoxic
naturally occurring substances, are being
tested as treatment for brain injury. Further
work is needed to determine appropriate
combinations of treatments and optimum times
of administration with respect to the time course
of the CNS disorder. In order to understand the
mechanisms that mediate traumatic brain injury
and repair, there must be a merging of findings
from neurochemical studies with data from
intensive behavioral testing
Effects of the Novel NMDA Receptor Antagonist Gacyclidine on Recovery From Medial Frontal Cortex Contusion Injury in Rats
Gacyclidine, a novel, noncompetitive NMDA receptor antagonist, was injected (i.v.) into rats at three different doses to determine if the drug could promote behavioral recovery and reduce the behavioral and anatomical impairments that occur after bilateral contusions of the medial frontal cortex (MFC). In the Morris water maze,contused rats treated with gacyciidine at a dosage of 0.1 mg/kg performed better than their vehicle-treated conspecifics. Rats given gacyclidine at either 0,3 or 0.03 mg/kg performed better than brain-injured controls, but not as well as those treated with 0.1 mg/kg. Counts of surviving neurons in the nucleus basalis magnoceilularis (NBM) and the medial dorsal nucleus (MDN) of the thalamus were used to determine whether gacyclidine treatment attenuated secondary cell death. In both the NBM and the MDN, the counts revealed fewer surviving neurons in untreated contused rats than in gacyclidine-treated rats. Increases in the size and number of microglia and astrocytes were observed in the striatum of gacyclidinetreated contused brains. Although most consequences of MFC contusions were attenuated, we still observed increases in ventricle dilation and thinning of the cortex. In fact, the ventricles of rats treated with 0.1 mg/kg of gacyclidine were larger than those of their vehicle treated counterparts, although we observed no behavioral impairment
Genomic profile of Toll-like receptor pathways in traumatically brain-injured mice: effect of exogenous progesterone
<p>Abstract</p> <p>Background</p> <p>Traumatic brain injury (TBI) causes acute inflammatory responses that result in an enduring cascade of secondary neuronal loss and behavioral impairments. It has been reported that progesterone (PROG) can inhibit the increase of some inflammatory cytokines and inflammation-related factors induced by TBI. Toll-like receptors (TLRs) play a critical role in the induction and regulation of immune/inflammatory responses. Therefore, in the present study, we examined the genomic profiles of TLR-mediated pathways in traumatically injured brain and PROG's effects on these genes.</p> <p>Methods</p> <p>Bilateral cortical impact injury to the medial frontal cortex was induced in C57BL/6J mice. PROG was injected (i.p., 16 mg/kg body weight) at 1 and 6 h after surgery. Twenty-four hours post-surgery, mice were killed and peri-contusional brain tissue was harvested for genomic detection and protein measurement. RT-PCR arrays were used to measure the mRNA of 84 genes in TLR-mediated pathways. Western blot, ELISA and immunohistochemistry were used to confirm the protein expression of genes of interest.</p> <p>Results</p> <p>We found that 2 TLRs (TLR1 and 2), 5 adaptor/interacting proteins (CD14, MD-1, HSPA1a, PGRP and Ticam2) and 13 target genes (Ccl2, Csf3, IL1a, IL1b, IL1r1, IL6, IL-10, TNFa, Tnfrsf1a, Cebpb, Clec4e, Ptgs2 and Cxcl10) were significantly up-regulated after injury. Administration of PROG significantly down-regulated three of the 13 increased target genes after TBI (Ccl-2, IL-1b and Cxcl-10), but did not inhibit the expression of any of the detected TLRs and adaptor/interacting proteins. Rather, PROG up-regulated the expression of one TLR (TLR9), 5 adaptor/interacting proteins, 5 effectors and 10 downstream target genes. We confirmed that Ccl-2, Cxcl-10, TLR2 and TLR9 proteins were expressed in brain tissue, a finding consistent with our observations of mRNA expression.</p> <p>Conclusion</p> <p>The results demonstrate that TBI can increase gene expression in TLR-mediated pathways. PROG does not down-regulate the increased TLRs or their adaptor proteins in traumatically injured brain. Reduction of the observed inflammatory cytokines by PROG does not appear to be the result of inhibiting TLRs or their adaptors in the acute stage of TBI.</p
An exploratory study examining the relationship between performance status and systemic inflammation frameworks and cytokine profiles in patients with advanced cancer
The role of cytokines in the systemic inflammatory response (SIR) is now well established. This is in keeping with the role of the SIR in tumorigenesis, malignant spread, and the development of cachexia. However, the relationship between performance status/systemic inflammation frameworks and cytokine profiles is not clear. The aim of the present study was to examine the relationship between the Eastern cooperative oncology group performance status/modified Glasgow prognostic score (ECOG-PS/mGPS) and cooperative oncology group performance status/neutrophil platelet score (ECOG-PS/NPS) frameworks and their cytokine profile in patients with advanced cancer.This was a retrospective interrogation of data already collected as part of a recent clinical trial (NCT00676936). The relationship between the independent variables (ECOG-PS/mGPS and ECOG-PS/NPS frameworks), and dependent variables (cytokine levels) was examined using independent Mann-Whitney U and Kruskal Wallis tests where appropriate.Of the 40 patients included in final analysis the majority had evidence of an SIR assessed by mGPS (78%) or NPS (53%). All patients died on follow-up and the median survival was 91 days (4-933 days). With increasing ECOG-PS there was a higher median value of Interleukin 6 (IL-6, P = .016) and C-reactive protein (CRP, P < .01) and lower albumin (P < .01) and poorer survival (P < .001). With increasing mGPS there was a higher median value of IL-6 (P = .016), Macrophage migration inhibitory factor (MIF, P = .010), erythrocyte sedimentation rate (ESR, P < .01) and poorer survival (P < .01). With increasing NPS there was a higher median value of TGF-β (P < .001) and C-reactive protein (P = .020) and poor survival (P = .001). When those patients with an ECOG-PS 0/1 and mGPS0 were compared with those patients with an ECOG-PS 2 and mGPS2 there was a higher median value of IL-6 (P = .017) and poorer survival (P < .001). When those patients with an ECOG-PS 0/1 and NPS0 were compared with those patients with an ECOG-PS 2 and NPS1/2 there was a higher median value of IL-6 (P = .002), TGF-β (P < .001) and poorer survival (P < .01).In patients with advanced cancer IL-6 was associated with the ECOG-PS/mGPS and ECOG-PS/NPS frameworks and survival in patients with advanced cancer. Therefore, the present work provides supporting evidence that agents targeting IL-6 are worthy of further exploration
Glibenclamide Administration Attenuates Infarct Volume, Hemispheric Swelling, and Functional Impairments following Permanent Focal Cerebral Ischemia in Rats
Studies from a single laboratory have shown that in rodent models of permanent stroke, administration of the sulfonylurea glibenclamide (Glib) is highly effective in reducing edema, mortality, and lesion volume. The Stroke Therapy Academic Industry Roundtable (STAIR) recommends that new acute treatments for ischemic stroke to be replicated across different laboratories. Accordingly, we examined the effect of low-dose Glib in a permanent suture occlusion model of stroke. Male Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (pMCAO) followed by an initial intraperitoneal injection of Glib (10 μg/kg) and the start of a constant infusion (200 ng/h) via miniosmotic pump at the onset of ischemia. Functional deficits were assessed by Neurological Severity Score (NSS) and grip-strength meter at 24 and 48 h after pMCAO. Glib-treated rats showed a significant reduction in infarct volume, lower NSS, and less hemispheric swelling compared to vehicle. Grip strength was decreased significantly in pMCAO rats compared to shams and significantly improved by treatment with Glib. Taken together, these data indicate that Glib has strong neuroprotective effects following ischemic stroke and may warrant further testing in future clinical trials for human stroke
Structure–activity relationship study of EphB3 receptor tyrosine kinase inhibitors
A structure–activity relationship study for a 2-chloroanilide derivative of pyrazolo[1,5-a]pyridine revealed that increased EphB3 kinase inhibitory activity could be accomplished by retaining the 2-chloroanilide and introducing a phenyl or small electron donating substituents to the 5-position of the pyrazolo[1,5-a]pyridine. In addition, replacement of the pyrazolo[1,5-a]pyridine with imidazo[1,2-a]pyridine was well tolerated and resulted in enhanced mouse liver microsome stability. The structure–activity relationship for EphB3 inhibition of both heterocyclic series was similar. Kinase inhibitory activity was also demonstrated for representative analogs in cell culture. An analog (32, LDN-211904) was also profiled for inhibitory activity against a panel of 288 kinases and found to be quite selective for tyrosine kinases. Overall, these studies provide useful molecular probes for examining the in vitro, cellular and potentially in vivo kinase-dependent function of EphB3 receptor
Decoherence, the measurement problem, and interpretations of quantum mechanics
Environment-induced decoherence and superselection have been a subject of
intensive research over the past two decades, yet their implications for the
foundational problems of quantum mechanics, most notably the quantum
measurement problem, have remained a matter of great controversy. This paper is
intended to clarify key features of the decoherence program, including its more
recent results, and to investigate their application and consequences in the
context of the main interpretive approaches of quantum mechanics.Comment: 41 pages. Final published versio
Methotrexate Inhibits T Cell Proliferation but Not Inflammatory Cytokine Expression to Modulate Immunity in People Living With HIV
Inflammation associated with increased risk of comorbidities persists in people living with HIV (PWH) on combination antiretroviral therapy (ART). A recent placebo-controlled trial of low-dose methotrexate (MTX) in PWH found that numbers of total CD4 and CD8 T cells decreased in the low-dose MTX arm. In this report we analyzed T cell phenotypes and additional plasma inflammatory indices in samples from the trial. We found that cycling (Ki67+) T cells lacking Bcl-2 were reduced by MTX but plasma inflammatory cytokines were largely unaffected. In a series of in vitro experiments to further investigate the mechanisms of MTX activity, we found that MTX did not inhibit effector cytokine production but inhibited T cell proliferation downstream of mTOR activation, mitochondrial function, and cell cycle entry. This inhibitory effect was reversible with folinic acid, suggesting low-dose MTX exerts anti-inflammatory effects in vivo in PWH largely by blocking T cell proliferation via dihydrofolate reductase inhibition, yet daily administration of folic acid did not rescue this effect in trial participants. Our findings identify the main mechanism of action of this widely used anti-inflammatory medicine in PWH and may provide insight into how MTX works in the setting of other inflammatory conditions
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