1,565 research outputs found

    Glial sulfatides and neuronal complex gangliosides are functionally interdependent in maintaining myelinating axon integrity

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    Sulfatides and gangliosides are raft-associated glycolipids essential for maintaining myelinated nerve integrity. Mice deficient in sulfatide (cerebroside sulfotransferase knockout, CST-/- ) or complex gangliosides (β-1,4-N-acetylegalactosaminyltransferase1 knockout, GalNAc-T-/- ) display prominent disorganization of proteins at the node of Ranvier (NoR) in early life, and age-dependent neurodegeneration. Loss of neuronal rather than glial complex gangliosides underpins the GalNAc-T-/- phenotype, as shown by neuron or glial-specific rescue, whereas sulfatide is principally expressed and functional in glial membranes. The similarities in NoR phenotype of CST-/- , GalNAc-T-/- and axo-glial protein deficient mice suggests these glycolipids stabilise membrane proteins including neurofascin155 (NF155) and myelin-associated glycoprotein (MAG) at axo-glial junctions. To assess the functional interactions between sulfatide and gangliosides, CST-/- and GalNAc-T-/- genotypes were interbred. CST-/- x GalNAc-T-/- mice develop normally to P10, but all die between P20-P25, coinciding with peak myelination. Ultrastructural, immunohistological and biochemical analysis of either sex reveals widespread axonal degeneration and disruption to the axo-glial junction at the NoR. In addition to sulfatide-dependent loss of NF155, CST-/-x GalNAc-T-/- mice exhibited a major reduction in MAG protein levels in CNS myelin, compared to wild type and single lipid deficient mice. The CST-/- x GalNAc-T-/- phenotype was fully restored to that of CST-/- mice by neuron-specific expression of complex gangliosides, but not by their glial-specific expression nor by the global expression of a-series gangliosides. These data indicate that sulfatide and complex b-series gangliosides on the glial and neuronal membranes respectively act in concert to promote NF155 and MAG in maintaining the stable axo-glial interactions essential for normal nerve function.SIGNIFICANCE STATEMENTSulfatides and complex gangliosides are membrane glycolipids with important roles in maintaining nervous system integrity. Node of Ranvier maintenance in particular requires stable compartmentalisation of multiple membrane proteins. The axo-glial adhesion molecules neurofascin 155 and myelin-associated glycoprotein require membrane microdomains containing either sulfatides or complex gangliosides to localise and function effectively. The co-operative roles of these microdomains and associated proteins are unknown. Here we show vital interdependent roles for sulfatides and complex gangliosides as double (but not single) deficiency causes a rapidly lethal phenotype in early age. These findings suggests that sulfatides and complex gangliosides on opposing axo-glial membranes are responsible for essential tethering of the axo-glial junction proteins, neurofascin155 and myelin-associated glycoprotein that interact to maintain the nodal complex

    Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement

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    <div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div

    R-CHOP versus R-CVP in the treatment of follicular lymphoma: a meta-analysis and critical appraisal of current literature

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    which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose: R-CHOP (rituximab with cyclophosphamide, doxorubicin, vincristine and prednisone) and R-CVP (rituximab with cyclophosphamide, vincristine and prednisone) have both been used successfully in the treatment of patients with symptomatic follicular lymphoma (FL). No study has compared the efficacy of the two treatment modalities and attempted to evaluate the role of anthracyclines in the management of patients with FL. We conducted a meta-analysis of relevant literature comparing the two treatment arms for FL with response being the final endpoint. Patients and Methods: Two analyses were conducted: The first analysis compared R-CHOP to R-CVP as frontline agents for the treatment of FL, and the second analysis included both untreated and relapsed patients. Results: For both studies, R-CVP was superior to R-CHOP when evaluating for complete response (CR). Odds ratios were 2.86 (95 % CI, 1.81–4.51) in the first analysis and 1.48 (95 % CI, 0.991–2.22) in the second analysis. However for overall response (CR+Partial response, PR), R-CHOP was superior, with odds ratios of 5.45 (95 % CI: 2.51 – 11.83) and 5.54 (95 % CI: 2.69

    Genetic variation exists for telomeric array organization within and among the genomes of normal, immortalized, and transformed chicken systems

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    This study investigated telomeric array organization of diverse chicken genotypes utilizing in vivo and in vitro cells having phenotypes with different proliferation potencies. Our experimental objective was to characterize the extent and nature of array variation present to explore the hypothesis that mega-telomeres are a universal and fixed feature of chicken genotypes. Four different genotypes were studied including normal (UCD 001, USDA-ADOL Line 0), immortalized (DF-1), and transformed (DT40) cells. Both cytogenetic and molecular approaches were utilized to develop an integrated view of telomeric array organization. It was determined that significant variation exists within and among chicken genotypes for chromosome-specific telomeric array organization and total genomic-telomeric sequence content. Although there was variation for mega-telomere number and distribution, two mega-telomere loci were in common among chicken genetic lines (GGA 9 and GGA W). The DF-1 cell line was discovered to maintain a complex derivative karyotype involving chromosome fusions in the homozygous and heterozygous condition. Also, the DF-1 cell line was found to contain the greatest amount of telomeric sequence per genome (17%) as compared to UCD 001 (5%) and DT40 (1.2%). The chicken is an excellent model for studying unique and universal features of vertebrate telomere biology, and characterization of the telomere length variation among genotypes will be useful in the exploration of mechanisms controlling telomere length maintenance in different cell types having unique phenotypes

    Modelling the Effect of Temperature on Respiration Rate of Fresh Cut Papaya (Carica papaya L.) Fruits.

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    A respiration rate (RR) model based on Peleg’s equation was developed for predicting RRs of fresh cut papaya. Respiration data for fresh cut papaya at 3/4 maturity were generated at temperatures 5, 10, 15, 20, 25 and 30°C using a closed system. RRs was found to be significantly influenced by storage temperature and increased from 0.021 to 0.289 mL[O2]/kg·h and 0.063 to 0.393 mL[CO2]/kg·h as a function of O2 and CO2 gas concentrations, respectively. Peleg’s constant K 1 and K 2 were obtained from linear regression analysis using GraphPad Prism 5.0 software and regression coefficients have good fit with values close to unity. The model was verified to assess the capability of its predictability of the RRs over the temperatures. There was good agreement with the experimentally estimated RRs. Information derived from the model can contribute in the design of successful modified atmospheric systems for storage of fresh cut papaya

    Results of the randomized phase IIB ARCTIC trial of low dose Rituximab in previously untreated CLL

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    ARCTIC was a multi-center, randomized-controlled, open, phase IIB non-inferiority trial in previously untreated Chronic Lymphocytic Leukemia (CLL). Conventional frontline therapy in fit patients is fludarabine, cyclophosphamide and rituximab (FCR). The trial hypothesized that including mitoxantrone with low-dose rituximab (FCM-miniR) would be non-inferior to FCR. 200 patients were recruited to assess the primary endpoint of complete remission (CR) rates according to IWCLL criteria. Secondary endpoints were progression-free survival (PFS), overall survival (OS), overall response rate, minimal residual disease (MRD) negativity, safety and cost-effectiveness. The trial closed following the pre-planned interim analysis. At final analysis, CR rates were 76% FCR vs 55% FCM-miniR [adjusted odds-ratio: 0.37; 95% CI: 0.19–0.73]. MRD-negativity rates were 54% FCR vs 44% FCM-miniR. More participants experienced Serious Adverse Reactions with FCM-miniR (49%) compared to FCR (41%). There are no significant differences between the treatment groups for PFS and OS. FCM-miniR is not expected to be cost-effective over a lifetime horizon. In summary, FCM-miniR is less well tolerated than FCR with an inferior response and MRD-negativity rate and increased toxicity, and will not be taken forward into a confirmatory trial. The trial demonstrated that oral FCR yields high response rates compared to historical series with intravenous chemotherapy

    X-ray emission from isolated neutron stars

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    X-ray emission is a common feature of all varieties of isolated neutron stars (INS) and, thanks to the advent of sensitive instruments with good spectroscopic, timing, and imaging capabilities, X-ray observations have become an essential tool in the study of these objects. Non-thermal X-rays from young, energetic radio pulsars have been detected since the beginning of X-ray astronomy, and the long-sought thermal emission from cooling neutron star's surfaces can now be studied in detail in many pulsars spanning different ages, magnetic fields, and, possibly, surface compositions. In addition, other different manifestations of INS have been discovered with X-ray observations. These new classes of high-energy sources, comprising the nearby X-ray Dim Isolated Neutron Stars, the Central Compact Objects in supernova remnants, the Anomalous X-ray Pulsars, and the Soft Gamma-ray Repeaters, now add up to several tens of confirmed members, plus many candidates, and allow us to study a variety of phenomena unobservable in "standard'' radio pulsars.Comment: Chapter to be published in the book of proceedings of the 1st Sant Cugat Forum on Astrophysics, "ICREA Workshop on the high-energy emission from pulsars and their systems", held in April, 201

    Spinal involvement in mucopolysaccharidosis IVA (Morquio-Brailsford or Morquio A syndrome): presentation, diagnosis and management.

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    Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio-Brailsford or Morquio A syndrome, is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase (GALNS). MPS IVA is multisystemic but manifests primarily as a progressive skeletal dysplasia. Spinal involvement is a major cause of morbidity and mortality in MPS IVA. Early diagnosis and timely treatment of problems involving the spine are critical in preventing or arresting neurological deterioration and loss of function. This review details the spinal manifestations of MPS IVA and describes the tools used to diagnose and monitor spinal involvement. The relative utility of radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of cervical spine instability, stenosis, and cord compression is discussed. Surgical interventions, anaesthetic considerations, and the use of neurophysiological monitoring during procedures performed under general anaesthesia are reviewed. Recommendations for regular radiological imaging and neurologic assessments are presented, and the need for a more standardized approach for evaluating and managing spinal involvement in MPS IVA is addressed
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