223 research outputs found

    Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

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    The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

    Localized Populations of CD8low/βˆ’ MHC Class I Tetramer+ SIV-Specific T Cells in Lymphoid Follicles and Genital Epithelium

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    CD8 T cells play an important role in controlling viral infections. We investigated the in situ localization of simian immunodeficiency virus (SIV)-specific T cells in lymph and genital tissues from SIV-infected macaques using MHC-class I tetramers. The majority of tetramer-binding cells localized in T cell zones and were CD8+. Curiously, small subpopulations of tetramer-binding cells that had little to no surface CD8 were detected in situ both early and late post-infection, and in both vaginally and rectally inoculated macaques. These tetramer+CD8low/βˆ’ cells were more often localized in apparent B cell follicles relative to T cell zones and more often found near or within the genital epithelium than the submucosa. Cells analyzed by flow cytometry showed similar populations of cells. Further immunohistological characterization revealed small populations of tetramer+CD20βˆ’ cells inside B cell follicles and that tetramer+ cells did not stain with Ξ³Ξ΄-TCR nor CD4 antibodies. Negative control tetramer staining indicated that tetramer+CD8low/βˆ’ cells were not likely NK cells non-specifically binding to MHC tetramers. These findings have important implications for SIV-specific and other antigen-specific T cell function in these specific tissue locations, and suggest a model in which antigen-specific CD8+ T cells down modulate CD8 upon entering B cell follicles or the epithelial layer of tissues, or alternatively a model in which only antigen-specific CD8 T cells that down-modulate CD8 can enter B cell follicles or the epithelium

    Plasma Biomarkers of Brain Atrophy in Alzheimer's Disease

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    Peripheral biomarkers of Alzheimer's disease (AD) reflecting early neuropathological change are critical to the development of treatments for this condition. The most widely used indicator of AD pathology in life at present is neuroimaging evidence of brain atrophy. We therefore performed a proteomic analysis of plasma to derive biomarkers associated with brain atrophy in AD. Using gel based proteomics we previously identified seven plasma proteins that were significantly associated with hippocampal volume in a combined cohort of subjects with AD (Nβ€Š=β€Š27) and MCI (Nβ€Š=β€Š17). In the current report, we validated this finding in a large independent cohort of AD (Nβ€Š=β€Š79), MCI (Nβ€Š=β€Š88) and control (Nβ€Š=β€Š95) subjects using alternative complementary methodsβ€”quantitative immunoassays for protein concentrations and estimation of pathology by whole brain volume. We confirmed that plasma concentrations of five proteins, together with age and sex, explained more than 35% of variance in whole brain volume in AD patients. These proteins are complement components C3 and C3a, complement factor-I, Ξ³-fibrinogen and alpha-1-microglobulin. Our findings suggest that these plasma proteins are strong predictors of in vivo AD pathology. Moreover, these proteins are involved in complement activation and coagulation, providing further evidence for an intrinsic role of these pathways in AD pathogenesis

    A new primary dental care service compared with standard care for child and family to reduce the re-occurrence of childhood dental caries (Dental RECUR): study protocol for a randomised controlled trial

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    Background: In England and Scotland, dental extraction is the single highest cause of planned admission to the hospital for children under 11 years. Traditional dental services have had limited success in reducing this disease burden. Interventions based on motivational interviewing have been shown to impact positively dental health behaviours and could facilitate the prevention of re-occurrence of dental caries in this high-risk population. The objective of the study is to evaluate whether a new, dental nurse-led service, delivered using a brief negotiated interview based on motivational interviewing, is a more cost-effective service than treatment as usual, in reducing the re-occurrence of dental decay in young children with previous dental extractions. Methods/Design: This 2-year, two-arm, multicentre, randomised controlled trial will include 224 child participants, initially aged 5 to 7 years, who are scheduled to have one or more primary teeth extracted for dental caries under general anaesthesia (GA), relative analgesia (RA: inhalation sedation) or local anaesthesia (LA). The trial will be conducted in University Dental Hospitals, Secondary Care Centres or other providers of dental extraction services across the United Kingdom. The intervention will include a brief negotiated interview (based on the principles of motivational interviewing) delivered between enrolment and 6 weeks post-extraction, followed by directed prevention in primary dental care. Participants will be followed up for 2 years. The main outcome measure will be the dental caries experienced by 2 years post-enrolment at the level of dentine involvement on any tooth in either dentition, which had been caries-free at the baseline assessment. Discussion: The participants are a hard-to-reach group in which secondary prevention is a challenge. Lack of engagement with dental care makes the children and their families scheduled for extraction particularly difficult to recruit to an RCT. Variations in service delivery between sites have also added to the challenges in implementing the Dental RECUR protocol during the recruitment phase. Trial registration: ISRCTN24958829 (date of registration: 27 September 2013), Current protocol version: 5.0

    Murine Missing in Metastasis (MIM) Mediates Cell Polarity and Regulates the Motility Response to Growth Factors

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    Missing in metastasis (MIM) is a member of the inverse BAR-domain protein family, and in vitro studies have implied MIM plays a role in deforming membrane curvature into filopodia-like protrusions and cell dynamics. Yet, the physiological role of the endogenous MIM in mammalian cells remains undefined.We have examined mouse embryonic fibroblasts (MEFs) derived from mice in which the MIM locus was targeted by a gene trapping vector. MIM(-/-) MEFs showed a less polarized architecture characterized by smooth edges and fewer cell protrusions as compared to wild type cells, although the formation of filopodia-like microprotrusions appeared to be normal. Immunofluorescent staining further revealed that MIM(-/-) cells were partially impaired in the assembly of stress fibers and focal adhesions but were enriched with transverse actin filaments at the periphery. Poor assembly of stress fibers was apparently correlated with attenuation of the activity of Rho GTPases and partially relieved upon overexpressing of Myc-RhoA(Q63L), a constitutively activated RhoA mutant. MIM(-/-) cells were also spread less effectively than wild type cells during attachment to dishes and substratum. Upon treatment with PDGF MIM(-/-) cells developed more prominent dorsal ruffles along with increased Rac1 activity. Compared to wild type cells, MIM(-/-) cells had a slower motility in the presence of a low percentage of serum-containing medium but migrated normally upon adding growth factors such as 10% serum, PDGF or EGF. MIM(-/-) cells were also partially impaired in the internalization of transferrin, fluorescent dyes, foreign DNAs and PDGF receptor alpha. On the other hand, the level of tyrosine phosphorylation of PDGF receptors was more elevated in MIM depleted cells than wild type cells upon PDGF treatment.Our data suggests that endogenous MIM protein regulates globally the cell architecture and endocytosis that ultimately influence a variety of cellular behaviors, including cell polarity, motility, receptor signaling and membrane ruffling

    Interplay between cell adhesion and growth factor receptors: from the plasma membrane to the endosomes

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    The emergence of multicellular animals could only take place once evolution had produced molecular mechanisms for cell adhesion and communication. Today, all metazoans express integrin-type adhesion receptors and receptors for growth factors. Integrins recognize extracellular matrix proteins and respective receptors on other cells and, following ligand binding, can activate the same cellular signaling pathways that are regulated by growth factor receptors. Recent reports have indicated that the two receptor systems also collaborate in many other ways. Here, we review the present information concerning the role of integrins as assisting growth factor receptors and the interplay between the receptors in cell signaling and in the orchestration of receptor recycling

    Prevalence of alexithymia and its association with anxiety and depression in a sample of Greek chronic obstructive pulmonary disease (COPD) outpatients

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    <p>Abstract</p> <p>Background</p> <p>Chronic obstructive pulmonary disease (COPD) is a major health problem, especially in adults over 40 years of age, and has a great social and economic impact. The psychological morbidity of COPD patients with regard to anxiety and depressive symptoms has been extensively studied in the past. However, few studies have investigated the prevalence of alexithymia in these patients, as well as its association with this comorbidity. Based on this fact, we studied the prevalence of alexithymia and its association with anxiety and depressive symptoms in COPD outpatients.</p> <p>Methods</p> <p>The present study included 167, randomly selected, outpatients diagnosed with COPD. Alexithymia, anxiety and depression were assessed using the Toronto Alexithymia Scale (TAS-20), Spielberger Trait Anxiety Inventory (STAI), and Beck Depression Inventory (BDI), respectively.</p> <p>Results</p> <p>The mean BDI score was 12.88 (SD: 7.7), mean STAI score 41.8 (SD: 11.0) and mean TAS-20 score 48.2 (SD: 11.5). No differences were observed between genders regarding age and alexithymia (t test <it>P </it>> 0.05), while female patients presented higher depression and trait anxiety scores than males (t test <it>P </it>< 0.05). Clinically significant levels of anxiety were present in 37.1% of men, and in 45.7% of women. The mean depression score was also higher than the corresponding mean score in the general population (one-sample t test <it>P </it>< 0.01), while 27.7% and 30.5% of the sample presented mild and moderate to severe depression, respectively. Finally, a strong correlation was observed between alexithymia, depression and anxiety.</p> <p>Conclusions</p> <p>This study confirms the high prevalence of anxiety and depression symptoms in Greek outpatients with COPD. The prevalence of alexithymia in COPD patients, contrary to what has been observed in patients with other chronic respiratory diseases, seem to be lower. However, we observed a strong association between alexithymia, depression and anxiety levels. This observation suggests that alexithymia should be taken into consideration when drafting specific psychotherapeutic interventions for these patients.</p
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