104 research outputs found
Motion perception deficits in glaucomatous optic neuropathy
AbstractThe mechanisms mediating impaired motion perception in glaucoma were investigated. Direction discrimination thresholds for low (4.2 deg/sec) and high (12.5 deg/sec) velocity random-dot kinematograms were measured in controls and patients with glaucoma or ocular hypertension. Thresholds were elevated significantly in glaucoma patients and individual ocular hypertensives. Threshold elevations were not due to blur or pupil size. After compensating for motion reversals, high but not low velocity thresholds remained elevated. Only high velocity thresholds correlated with differential luminance sensitivity. A hypothesis that different mechanisms mediate glaucoma-induced deficits at high and low velocities is presented
Evolution of MS lesions to black holes under DNA vaccine treatment
Persistent black holes (PBH) are associated with axonal loss and disability progression in multiple sclerosis (MS). The objective of this work was to determine if BHT-3009, a DNA plasmid-encoding myelin basic protein (MBP), reduces the risk of new lesions becoming PBH, compared to placebo, and to test if pre-treatment serum anti-MBP antibody levels impact on the effect of BHT-3009 treatment. In this retrospective, blinded MRI study, we reviewed MRI scans of 155 MS patients from a double-blind, randomized, phase II trial with three treatment arms (placebo, 0.5 and 1.5mg BHT-3009). New lesions at weeks 8 and 16 were tracked at week 48 and those appearing as T1-hypointense were classified as PBH. A subset of 46 patients with available pre-treatment serum anti-MBP IgM levels were analyzed separately. Overall, there was no impact of treatment on the risk for PBH. However, there was a significant interaction between anti-MBP antibodies and treatment effect: patients receiving 0.5mg BHT-3009 showed a reduced risk of PBH with higher antibody levels compared to placebo (p<0.01). Although we found no overall reduction of the risk for PBH in treated patients, there may be an effect of low-dose BHT-3009, depending on the patients' pre-treatment immune response
Twin Town in South Brazil: A Nazi's Experiment or a Genetic Founder Effect?
Cândido Godói (CG) is a small municipality in South Brazil with approximately 6,000 inhabitants. It is known as the “Twins' Town” due to its high rate of twin births. Recently it was claimed that such high frequency of twinning would be connected to experiments performed by the German Nazi doctor Joseph Mengele. It is known, however, that this town was founded by a small number of families and therefore a genetic founder effect may represent an alternatively explanation for the high twinning prevalence in CG. In this study, we tested specific predictions of the “Nazi's experiment” and of the “founder effect” hypotheses. We surveyed a total of 6,262 baptism records from 1959–2008 in CG catholic churches, and identified 91 twin pairs and one triplet. Contrary to the “Nazi's experiment hypothesis”, there is no spurt in twinning between the years (1964–1968) when Mengele allegedly was in CG (P = 0.482). Moreover, there is no temporal trend for a declining rate of twinning since the 1960s (P = 0.351), and no difference in twinning among CG districts considering two different periods: 1927–1958 and 1959–2008 (P = 0.638). On the other hand, the “founder effect hypothesis” is supported by an isonymy analysis that shows that women who gave birth to twins have a higher inbreeding coefficient when compared to women who never had twins (0.0148, 0.0081, respectively, P = 0.019). In summary, our results show no evidence for the “Nazi's experiment hypothesis” and strongly suggest that the “founder effect hypothesis” is a much more likely alternative for explaining the high prevalence of twinning in CG. If this hypothesis is correct, then this community represents a valuable population where genetic factors linked to twinning may be identified
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Defective sphingosine-1-phosphate receptor 1 (S1P1) phosphorylation exacerbates TH17-mediated autoimmune neuroinflammation
Sphingosine-1-phosphate (S1P) signaling regulates lymphocyte egress from lymphoid organs into systemic circulation. Sphingosine phosphate receptor 1 (S1P1) agonist, FTY-720 (Gilenya™) arrests immune trafficking and prevents multiple sclerosis (MS) relapses. However, alternative mechanisms of S1P-S1P1 signaling have been reported. Phosphoproteomic analysis of MS brain lesions revealed S1P1 phosphorylation on S351, a residue crucial for receptor internalization. Mutant mice harboring a S1pr1 gene encoding phosphorylation-deficient receptors [S1P1(S5A)] developed severe experimental autoimmune encephalomyelitis (EAE) due to T helper (TH) 17-mediated autoimmunity in the peripheral immune and nervous system. S1P1 directly activated Janus-like kinase–signal transducer and activator of transcription 3 (JAK-STAT3) pathway via interleukin 6 (IL-6). Impaired S1P1 phosphorylation enhances TH17 polarization and exacerbates autoimmune neuroinflammation. These mechanisms may be pathogenic in MS
Lysosomal and vacuolar sorting: not so different after all!
Soluble hydrolases represent the main proteins of lysosomes and vacuoles and are essential to sustain the lytic properties of these organelles typical for the eukaryotic organisms. The sorting of these proteins from ER residents and secreted proteins is controlled by highly specific receptors to avoid mislocalization and subsequent cellular damage. After binding their soluble cargo in the early stage of the secretory pathway, receptors rely on their own sorting signals to reach their target organelles for ligand delivery, and to recycle back for a new round of cargo recognition. Although signals in cargo and receptor molecules have been studied in human, yeast and plant model systems, common denominators and specific examples of diversification have not been systematically explored. This review aims to fill this niche by comparing the structure and the function of lysosomal/vacuolar sorting receptors (VSRs) from these three organisms
The requirements for natural Th17 cell development are distinct from those of conventional Th17 cells
A distinct population of Th17 cells develops in the thymus with innate immune cell characteristics, different selection requirements, and skewed TCR gene usage compared with peripheral Th17 cells
Efficient precision quantization in AdS/CFT
Understanding finite-size effects is one of the key open questions in solving
planar AdS/CFT. In this paper we discuss these effects in the AdS_5xS^5 string
theory at one-loop in the world-sheet coupling. First we provide a very
general, efficient way to compute the fluctuation frequencies, which allows to
determine the energy shift for very general multi-cut solutions. Then we apply
this to two-cut solutions, in particular the giant magnon and determine the
finite-size corrections at subleading order. The latter are then compared to
the finite-size corrections from Luscher-Klassen-Melzer formulas and found to
be in perfect agreement.Comment: 32 pages, 5 figures; v2: typos corrected, refs adde
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