603 research outputs found
Analysis of Fcγ receptor haplotypes in rheumatoid arthritis: FCGR3A remains a major susceptibility gene at this locus, with an additional contribution from FCGR3B
The Fcγ receptors play important roles in the initiation and regulation of many immunological and inflammatory processes, and genetic variants (FCGR) have been associated with numerous autoimmune and infectious diseases. The data in rheumatoid arthritis (RA) are conflicting and we previously demonstrated an association between FCGR3A and RA. In view of the close molecular proximity with FCGR2A, FCGR2B and FCGR3B, additional polymorphisms within these genes and FCGR haplotypes were examined to refine the extent of association with RA. Biallelic polymorphisms in FCGR2A, FCGR2B and FCGR3B were examined for association with RA in two well characterized UK Caucasian and North Indian/Pakistani cohorts, in which FCGR3A genotyping had previously been undertaken. Haplotype frequencies and linkage disequilibrium were estimated across the FCGR locus and a model-free analysis was performed to determine association with RA. This was followed by regression analysis, allowing for phase uncertainty, to identify the particular haplotype(s) that influences disease risk. Our results reveal that FCGR2A, FCGR2B and FCGR3B were not associated with RA. The haplotype with the strongest association with RA susceptibility was the FCGR3A–FCGR3B 158V-NA2 haplotype (odds ratio 3.18, 95% confidence interval 1.13–8.92 [P = 0.03] for homozygotes compared with all genotypes). The association was stronger in the presence of nodules (odds ratio 5.03, 95% confidence interval 1.44–17.56; P = 0.01). This haplotype was also more common in North Indian/Pakistani RA patients than in control individuals, but not significantly so. Logistic regression analyses suggested that FCGR3A remained the most significant gene at this locus. The increased association with an FCGR3A–FCGR3B haplotype suggests that other polymorphic variants within FCGR3A or FCGR3B, or in linkage disequilibrium with this haplotype, may additionally contribute to disease pathogenesis
Mitigation-driven translocations: are we moving wildlife in the right direction?
Despite rapid growth in the field of reintroduction biology, many lessons learned from scientific research are not being applied to translocations initiated when human land-use conflicts with persistence of a species. Mitigation-driven translocations outnumber and receive better funding than science-based conservation translocations worldwide, yet their conservation benefit is unclear. As mitigation releases are economically motivated, outcomes may diverge greatly from releases designed to serve the biological needs of species. Translocation as a regulatory tool may be ill-fitted to biologically mitigate environmental damage wrought by development. Evidence suggests that many mitigation-driven translocations fail, though application of scientific principles and best-practices could likely increase success. Furthermore, lack of transparency and documentation of outcomes hinder efforts to understand the scope of the problem. If mitigation-driven translocations continue unabated as a part of the growing billion-dollar ecological consulting industry, it is imperative that the scale and effects of these releases are reported and evaluated
Global use of Haemophilus influenzae type b conjugate vaccine.
Haemophilus influenzae type b (Hib) conjugate vaccines have been underutilized globally. We report progress in global use of Hib vaccines included in national immunization schedules. The number of countries using Hib vaccine increased from 89/193 (46%) in 2004 to 158/193 (82%) by the end of 2009. The increase was greatest among low-income countries eligible for financial support from the GAVI Alliance [13/75 (17%) in 2004, 60/72 (83%) by the end of 2009], and can be attributed to various factors. Additional efforts are still needed to increase vaccine adoption in lower middle income countries [20/31 (65%) by the end of 2009]
Rfam: updates to the RNA families database
Rfam is a collection of RNA sequence families, represented by multiple sequence alignments and covariance models (CMs). The primary aim of Rfam is to annotate new members of known RNA families on nucleotide sequences, particularly complete genomes, using sensitive BLAST filters in combination with CMs. A minority of families with a very broad taxonomic range (e.g. tRNA and rRNA) provide the majority of the sequence annotations, whilst the majority of Rfam families (e.g. snoRNAs and miRNAs) have a limited taxonomic range and provide a limited number of annotations. Recent improvements to the website, methodologies and data used by Rfam are discussed. Rfam is freely available on the Web at http://rfam.sanger.ac.uk/and http://rfam.janelia.org/
Neural stem cells restore myelin in a demyelinating model of Pelizaeus-Merzbacher disease
Pelizaeus-Merzbacher disease is a fatal X-linked leukodystrophy caused by mutations in the PLP1 gene, which is expressed in the CNS by oligodendrocytes. Disease onset, symptoms and mortality span a broad spectrum depending on the nature of the mutation and thus the degree of CNS hypomyelination. In the absence of an effective treatment, direct cell transplantation into the CNS to restore myelin has been tested in animal models of severe forms of the disease with failure of developmental myelination, and more recently, in severely affected patients with early disease onset due to point mutations in the PLP1 gene, and absence of myelin by MRI. In patients with a PLP1 duplication mutation, the most common cause of Pelizaeus-Merzbacher disease, the pathology is poorly defined because of a paucity of autopsy material. To address this, we examined two elderly patients with duplication of PLP1 in whom the overall syndrome, including end-stage pathology, indicated a complex disease involving dysmyelination, demyelination and axonal degeneration. Using the corresponding Plp1 transgenic mouse model, we then tested the capacity of transplanted neural stem cells to restore myelin in the context of PLP overexpression. Although developmental myelination and axonal coverage by endogenous oligodendrocytes was extensive, as assessed using electron microscopy (n = 3 at each of four end points) and immunostaining (n = 3 at each of four end points), wild-type neural precursors, transplanted into the brains of the newborn mutants, were able to effectively compete and replace the defective myelin (n = 2 at each of four end points). These data demonstrate the potential of neural stem cell therapies to restore normal myelination and protect axons in patients with PLP1 gene duplication mutation and further, provide proof of principle for the benefits of stem cell transplantation for other fatal leukodystrophies with ‘normal’ developmental myelination
Recommended from our members
A quantum theory account of order effects and conjunction fallacies in political judgments
Are our everyday judgments about the world around us normative? Decades of research in the judgment and decision-making literature suggest the answer is no. If people's judgments do not follow normative rules, then what rules if any do they follow? Quantum probability theory is a promising new approach to modeling human behavior that is at odds with normative, classical rules. One key advantage of using quantum theory is that it explains multiple types of judgment errors using the same basic machinery, unifying what have previously been thought of as disparate phenomena. In this article, we test predictions from quantum theory related to the co-occurrence of two classic judgment phenomena, order effects and conjunction fallacies, using judgments about real-world events (related to the U.S. presidential primaries). We also show that our data obeys two a priori and parameter free constraints derived from quantum theory. Further, we examine two factors that moderate the effects, cognitive thinking style (as measured by the Cognitive Reflection Test) and political ideology
Oligodendroglial modulation of fast axonal transport in a mouse model of hereditary spastic paraplegia
Oligodendrocytes are critical for the development of the plasma membrane and cytoskeleton of the axon. In this paper, we show that fast axonal transport is also dependent on the oligodendrocyte. Using a mouse model of hereditary spastic paraplegia type 2 due to a null mutation of the myelin Plp gene, we find a progressive impairment in fast retrograde and anterograde transport. Increased levels of retrograde motor protein subunits are associated with accumulation of membranous organelles distal to nodal complexes. Using cell transplantation, we show categorically that the axonal phenotype is related to the presence of the overlying Plp null myelin. Our data demonstrate a novel role for oligodendrocytes in the local regulation of axonal function and have implications for the axonal loss associated with secondary progressive multiple sclerosis
Coordination-cage binding and catalysed hydrolysis of organophosphorus chemical warfare agent simulants
The use of organophosphorus chemical warfare agents still remains an ongoing global threat. Here we investigate the binding of small-molecule organic guests including phosphate esters, sulfonate esters, carbonate esters and a sulfite ester – some of which act as simulants for organophosphorus chemical warfare agents – in the cavity of a water-soluble coordination cage. For several of these guest species, binding constants in the range 102 to 103 M−1 were determined in water/DMSO (98 : 2 v/v) solution, through a combination of fluorescence and 1H NMR spectroscopy, and subsequent fitting of titration data to a 1 : 1 binding isotherm model. For three cage/guest complexes crystallographic structure determinations were possible: in two cases (with guests phenyl methanesulfonate and phenyl propyl carbonate) the guest lies inside the cavity, forming a range of CH⋯O hydrogen-bonding interactions with the cage interior surface involving CH groups on the cationic cage surface that act as H-bond donors and O atoms on the guests that act as H-bond acceptors. In a third case, with the guest 4-nitrophenyl-methanesulfonate, the guest lies in the spaces outside a cage cavity between cages and forms weak CH⋯O interactions with the cage exterior surface: the cavity is occupied by a network of H-bonded water molecules, though this guest does show cavity binding in solution. For the isomeric guests 4-nitrophenyl-methanesulfonate and 4-nitrophenyl methyl sulfite, hydrolysis in water/DMSO (98 : 2 v/v) could be monitored colorimetrically via appearance of the 4-nitrophenolate anion; both showed accelerated hydrolysis rates in the presence of the host cage with second-order rate constants for the catalysed reactions in the range 10−3 to 10−2 M−1 s−1 at pH 9. The typical rate dependence on external pH and the increased reaction rates when chloride ions are present (which can bind inside the cavity and displace other cavity-bound guests) imply that the catalysed reaction actually occurs at the external surface of the cage rather than inside the cavity
Quantum dynamics as a physical resource
How useful is a quantum dynamical operation for quantum information
processing? Motivated by this question we investigate several strength measures
quantifying the resources intrinsic to a quantum operation. We develop a
general theory of such strength measures, based on axiomatic considerations
independent of state-based resources. The power of this theory is demonstrated
with applications to quantum communication complexity, quantum computational
complexity, and entanglement generation by unitary operations.Comment: 19 pages, shortened by 3 pages, mainly cosmetic change
Diagnostic Delay Is Associated with Complicated Disease and Growth Impairment in Paediatric Crohn\u27s Disease
Background: Paediatric data on the association between diagnostic delay and inflammatory bowel disease [IBD] complications are lacking. We aimed to determine the effect of diagnostic delay on stricturing/fistulising complications, surgery, and growth impairment in a large paediatric cohort, and to identify predictors of diagnostic delay. Methods: We conducted a national, prospective, multicentre IBD inception cohort study including 1399 children. Diagnostic delay was defined as time from symptom onset to diagnosis \u3e75th percentile. Multivariable proportional hazards [PH] regression was used to examine the association between diagnostic delay and stricturing/fistulising complications and surgery, and multivariable linear regression to examine the association between diagnostic delay and growth. Predictors of diagnostic delay were identified using Cox PH regression. Results: Overall (64% Crohn\u27s disease [CD]; 36% ulcerative colitis/IBD unclassified [UC/IBD-U]; 57% male]), median time to diagnosis was 4.2 (interquartile range [IQR] 2.0-9.2) months. For the overall cohort, diagnostic delay was \u3e9.2 months; in CD, \u3e10.8 months and in UC/IBD-U, \u3e6.6 months. In CD, diagnostic delay was associated with a 2.5-fold higher rate of strictures/internal fistulae (hazard ratio [HR] 2.53, 95% confidence interval [CI] 1.41-4.56). Every additional month of diagnostic delay was associated with a decrease in height-for-age z-score of 0.013 standard deviations [95% CI 0.005-0.021]. Associations persisted after adjusting for disease location and therapy. No independent association was observed between diagnostic delay and surgery in CD or UC/IBD-U. Diagnostic delay was more common in CD, particularly small bowel CD. Abdominal pain, including isolated abdominal pain in CD, was associated with diagnostic delay. Conclusions: Diagnostic delay represents a risk factor for stricturing/internal fistulising complications and growth impairment in paediatric CD
- …