665 research outputs found
Platelets roll on stimulated endothelium in vivo: an interaction mediated by endothelial P-selectin.
Immunohistochemical detection of macrophage migration inhibitory factor in fetal and adult bovine epididymis: Release by the apocrine secretion mode?
Originally defined as a lymphokine inhibiting the random migration of macrophages, the macrophage migration inhibitory factor (MIF) is an important mediator of the host response to infection. Beyond its function as a classical cytokine, MIF is currently portrayed as a multifunctional protein with growth-regulating properties present in organ systems beyond immune cells. In previous studies, we detected substantial amounts of MIF in the rat epididymis and epididymal spermatozoa, where it appears to play a role during post-testicular sperm maturation and the acquisition of fertilization ability. To explore its presence in other species not yet examined in this respect, we extended the range of studies to the bull. Using a polyclonal antibody raised against MIF purified from bovine eye lenses, we detected MIF in the epithelium of the adult bovine epididymis with the basal cells representing a prominently stained cell type. A distinct accumulation of MIF at the apical cell pole of the epithelial cells and in membranous vesicles localized in the lumen of the epididynnal duct was obvious. In the fetal bovine epididymis, we also detected MIF in the epithelium, whereas MIF accumulation was evident at the apical cell surface and in apical protrusions. By immuno-electron microscopy of the adult bovine epididymis, we localized MIF in apical protrusions of the epithelial cells and in luminal membrane-bound vesicles that were found in close proximity to sperm cells. Although the precise origin of the MIF-containing vesicles remains to be delineated, our morphological observations support the hypothesis that they become detached from the apical surface of the epididymal epithelial cells. Additionally, an association of MIF with the outer dense fibers of luminal spermatozoa was demonstrated. Data obtained in this study suggest MIF release by an apocrine secretion mode in the bovine epididymis. Furthermore, MIF localized in the basal cells of the epithelium and in the connective tissue could be responsible for regulating the migration of macrophages in order to avoid contact of immune cells with spermatozoa that carry a wide range of potent antigens. Copyright (c) 2006 S. Karger AG, Basel
Imaging of z~2 QSO host galaxies with the Hubble Space Telescope
We report on deep imaging in 2 filters with the PC2 camera of HST, of five
QSOs at redshift ~2, with a range of optical and radio luminosity. The
observations included a suite of PSF observations which were used to construct
new PSF models, described elsewhere by Dumont et al. The new PSF models were
used to remove the QSO nucleus from the images. We find that the host galaxies
have resolved flux of order 10% of the QSO nuclei, and are generally luminous
and blue, indicating active star-formation. While most have clearly irregular
morphologies, the bulk of the flux can be modelled approximately by an r**1/4
law. However, all host galaxies also have an additional approximately
exponential luminosity profile beyond a radius about 0.8 arcsec, as also seen
in ground-based data with larger telescopes. The QSOs all have a number of
nearby faint blue companions which may be young galaxies at the QSO redshift.
We discuss implications for evolution of the host galaxies, their spheroidal
populations, and central black holes.Comment: 18 pages including 2 tables; to appear in A
Role of P-selectin in platelet sequestration in pulmonary capillaries during endotoxemia
Background: There is growing evidence that platelets accumulate in the lung and contribute to the pathogenesis of acute lung injury during endotoxemia. The aims of the present study were to localize platelet sequestration in the pulmonary microcirculation and to investigate the role of P-selectin as a molecular mechanism of platelet endothelial cell interaction. Methods: We used in vivo fluorescence microscopy to quantify the kinetics of fluorescently labeled erythrocytes and platelets in alveolar capillary networks in rabbit lungs. Results: Six hours after onset of endotoxin infusion we observed a massive rolling along and firm adherence of platelets to lung capillary endothelial cells whereas under control conditions no platelet sequestration was detected. P-selectin was expressed on the surface of separated platelets which were incubated with endotoxin and in lung tissue. Pretreatment of platelets with fucoidin, a P-selectin antagonist, significantly attenuated the endotoxin-induced platelet rolling and adherence. In contrast, intravenous infusion of fucoidin in endotoxin-treated rabbits did not inhibit platelet sequestration in pulmonary capillaries. Conclusion: We conclude that platelets accumulate in alveolar capillaries following endotoxemia. P-selectin expressed on the surface of platelets seems to play an important role in mediating this platelet-endothelial cell interaction. Copyright (c) 2006 S. Karger AG, Basel
Pharmacological interventions for agitation in patients with traumatic brain injury: protocol for a systematic review and meta-analysis
Abstract Background Traumatic brain injury (TBI) is a worldwide leading cause of mortality and disability. Among TBI complications, agitation is a frequent behavioural problem. Agitation causes potential harm to patients and caregivers, interferes with treatments, leads to unnecessary chemical and physical restraints, increases hospital length of stay, delays rehabilitation, and impedes functional independence. Pharmacological treatments are often considered for agitation management following TBI. Several types of agents have been proposed for the treatment of agitation. However, the benefit and safety of these agents in TBI patients as well as their differential effects and interactions are uncertain. In addition, animal studies and observational studies have suggested impaired cognitive function with the use of certain antipsychotics and benzodiazepines. Hence, a safe and effective treatment for agitation, which does not interfere with neurological recovery, remains to be identified. Methods/design With the help of Health Sciences librarian, we will design a search strategy in the following databases: PubMed, Ovid MEDLINE®, EMBASE, CINAHL, PsycINFO, Cochrane Library, Google Scholar, Directory of Open Access Journals, LILACS, Web of Science, and Prospero. A grey literature search will be performed using the resources suggested in CADTH’s Grey Matters. We will include all randomized controlled, quasi-experimental, and observational studies with control groups. The population of interest is all patients, including children and adults, who have suffered a TBI. We will include studies in which agitation, not further defined, was the presenting symptom or one of the presenting symptoms. We will also include studies where agitation was not the presenting symptom but was measured as an outcome variable and studies assessing the safety of these pharmacological interventions in TBI patients. We will include studies evaluating all pharmacological interventions including beta-adrenergic blockers, typical and atypical antipsychotics, anticonvulsants, dopamine agonists, psychostimulants, antidepressants, alpha-2-adrenergic agonists, hypnotics, and anxiolytics. Discussion Although agitation is frequent following TBI and pharmacological agents that are often used, there is no consensus on the most efficacious and safest strategy to treat these complications. There is a need for an updated systematic review to summarize the evidence in order to inform practice and future research. Systematic review registration PROSPERO CRD4201603314
Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space
Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202
Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space
Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202
A Placebo-Controlled, Multicenter, Double-Blind, Phase 2 Randomised Trial of the Pan-Caspase Inhibitor Emricasan in Patients with Acutely Decompensated Cirrhosis
Background: Cirrhosis and acute-on-chronic liver failure (ACLF) are associated with systemic inflammation, and caspase-mediated hepatocyte cell death. Emricasan is a novel, pan-caspase inhibitor. Aims of this study were to assess the pharmacokinetics, pharmacodynamics, safety and clinical outcomes of emricasan in acute decompensation (AD) of cirrhosis. Methods: This was a phase 2, multicentre, double-blind, randomised trial. The primary objective was to evaluate the pharmacokinetics, pharmacodynamics and safety of emricasan in patients with cirrhosis presenting with AD and organ failure. AD was defined as an acute decompensating event ≤6 weeks' duration. Patients were randomised proportionately to emricasan 5. mg bid, emricasan 25. mg bid, emricasan 50. mg bid or placebo. Treatment was continued to 28 days, or voluntary discontinuation. Results: Twenty-three subjects were randomised, of whom 21 were dosed (placebo n = 4; 5. mg n = 5; 25. mg n = 7; 50. mg n = 5). Pharmacokinetic data showed 5. mg dose was associated with low plasma levels ( < 50. ng/ml), and 25. mg and 50. mg doses showed comparable pharmacokinetic profiles. Therefore, for analysis of secondary endpoints, placebo and 5. mg groups were merged into a 'placebo/low-dose' group, and 25. mg and 50. mg groups were merged into a 'high-dose' group. Five deaths occurred amongst the 21 patients, all due to progression of liver disease (2 in placebo/low-dose, 3 in high-dose). No statistically significant changes from baseline MELD score or CLIF-C ACLF score were noted between placebo/low-dose and high-dose groups at day 7 (MELD -1 vs -1, CLIF-C ACLF 0.7 vs 0.8). An initial reduction in cleaved keratin M30 fragment was noted between placebo/low-dose and high-dose groups (percent relative change: day 2: -11.6 vs -42.6, P = 0.017, day 4: -3.5 vs -38.9 P = 0.017) although this did not persist to day 7 (-3.1 vs -20.8, P = 0.342). Conclusion: This study demonstrates that emricasan is safe and well tolerated in advanced liver disease. However, this study fails to provide proof-of-concept support for caspase inhibition as a treatment strategy for ACLF. Trial registration: EudraCT 2012-004245-33
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