228 research outputs found
The Seroepidemiology of Haemophilus influenzae Type B Prior to Introduction of an Immunization Programme in Kathmandu, Nepal.
Haemophilus influenzae type b (Hib) is now recognized as an important pathogen in Asia. To evaluate disease susceptibility, and as a marker of Hib transmission before routine immunization was introduced in Kathmandu, 71 participants aged 7 months-77 years were recruited and 15 cord blood samples were collected for analysis of anti-polyribosylribitol phosphate antibody levels by enzyme-linked immunosorbent assay. Only 20% of children under 5 years old had levels considered protective (>0.15 µg/ml), rising to 83% of 15-54 year-olds. Prior to introduction of Hib vaccine in Kathmandu, the majority of young children were susceptible to disease
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Correlated Excitonic Signatures in a Nanoscale van der Waals Antiferromagnet
Composite quasi-particles with emergent functionalities in spintronic and
quantum information science can be realized in correlated materials due to
entangled charge, spin, orbital, and lattice degrees of freedom. Here we show
that by reducing the lateral dimension of correlated antiferromagnet NiPS3
flakes to tens of nanometers, we can switch-off the bulk spin-orbit entangled
exciton in the near-infrared (1.47 eV) and activate visible-range (1.8 to 2.2
eV) transitions with charge-transfer character. These ultra-sharp lines (<120
ueV at 4.2 K) share the spin-correlated nature of the bulk exciton by
displaying a Neel temperature dependent linear polarization. Furthermore,
exciton photoluminescence lineshape analysis reveals a polaronic character via
coupling with at-least 3 phonon modes and a comb-like Stark effect through
discretization of charges in each layer. These findings augment the knowledge
on the many-body nature of excitonic quasi-particles in correlated
antiferromagnets and also establish the nanoscale platform as promising for
maturing integrated magneto-optic devices
Linear discriminant analysis reveals differences in root architecture in wheat seedlings by nitrogen uptake efficiency
Root architecture impacts water and nutrient uptake efficiency. Identifying exactly which root architectural properties influence these agronomic traits can prove challenging. In this paper approximately 300 wheat plants were divided into four groups using two binary classifications, high vs. low nitrogen uptake efficiency (NUpE), and high vs. low nitrate in medium. The root system architecture for each wheat plant was captured using 16 quantitative variables. The multivariate analysis tool, linear discriminant analysis, was used to construct composite variables, each a linear combination of the original variables, such that the score of the wheat plants on the new variables showed the maximum between-group variability. The results show that the distribution of root system architecture traits differ between low and high NUpE wheat plants and, less strongly, between low NUpE wheat plants grown on low vs. high nitrate media
GLA-modified RNA treatment lowers GB3 levels in iPSC-derived cardiomyocytes from Fabry-affected individuals
Recent studies in non-human model systems have shown therapeutic potential of nucleoside-modified messenger RNA (modRNA) treatments for lysosomal storage diseases. Here, we assessed the efficacy of a modRNA treatment to restore the expression of the galactosidase alpha (GLA), which codes for α-Galactosidase A (α-GAL) enzyme, in a human cardiac model generated from induced pluripotent stem cells (iPSCs) derived from two individuals with Fabry disease. Consistent with the clinical phenotype, cardiomyocytes from iPSCs derived from Fabry-affected individuals showed accumulation of the glycosphingolipid Globotriaosylceramide (GB3), which is an α-galactosidase substrate. Furthermore, the Fabry cardiomyocytes displayed significant upregulation of lysosomal-associated proteins. Upon GLA modRNA treatment, a subset of lysosomal proteins were partially restored to wild-type levels, implying the rescue of the molecular phenotype associated with the Fabry genotype. Importantly, a significant reduction of GB3 levels was observed in GLA modRNA-treated cardiomyocytes, demonstrating that α-GAL enzymatic activity was restored. Together, our results validate the utility of iPSC-derived cardiomyocytes from affected individuals as a model to study disease processes in Fabry disease and the therapeutic potential of GLA modRNA treatment to reduce GB3 accumulation in the heart.</p
Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.
The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD
A mixed method, phase 2 clinical evaluation of a novel device to treat postpartum haemorrhage
Background: We evaluated the safety, efficacy, and acceptability of a new device designed to facilitate uterine compression in women with postpartum haemorrhage (PPH).
Methods: A prospective, phase two clinical device trial with concurrent qualitative study, conducted in a UK consultant obstetric unit. The device was used in addition to standard care in women unresponsive to initial oxytocin therapy. The primary effectiveness outcome was additional blood loss of over 1000mls, whilst safety was assessed through adverse events. Interviews assessed device feasibility and acceptability, and were analysed using framework analysis.
Results: We recruited 57 women with clinical PPH after vaginal birth; 67% were primiparous and 47% had undergone operative birth. All but two (96%) had atony as a cause of the haemorrhage; in addition, 30% also had bleeding from lacerations and 11% had retained tissue. After device use, only one woman had additional blood loss over 1000mls, although 3 women (7%) needed a Bakri balloon and 14% received a blood transfusion. All but one clinician felt that the device was easy to use. Clinicians stated that the device assisted management in 85% of cases. All 56 women who responded stated that if they bled in a future birth they would want the device to be used again. There were no serious adverse events related to the device. However, 3 events were judged as 'possibly' being caused by the device - 2 minor vaginal grazes and one postnatal episiotomy infection and breakdown. Lax vaginal tissue complicated the use of the device in three women. In 47 interviews, participants, birth partners, clinician users and attending midwives viewed the device positively. Clinicians found it useful as a way of stopping blood loss and as an aid to diagnose the source of bleeding.
Conclusions: The PPH Butterfly may provide a rapid, acceptable and effective treatment for postpartum haemorrhage
Lysyl hydroxylase 3 localizes to epidermal basement membrane and Is reduced in patients with Recessive Dystrophic Epidermolysis Bullosa
Recessive dystrophic epidermolysis bullosa (RDEB) is caused by mutations in COL7A1 resulting in reduced or absent type VII collagen, aberrant anchoring fibril formation and subsequent dermal-epidermal fragility. Here, we identify a significant decrease in PLOD3 expression and its encoded protein, the collagen modifying enzyme lysyl hydroxylase 3 (LH3), in RDEB. We show abundant LH3 localising to the basement membrane in normal skin which is severely depleted in RDEB patient skin. We demonstrate expression is in-part regulated by endogenous type VII collagen and that, in agreement with previous studies, even small reductions in LH3 expression lead to significantly less secreted LH3 protein. Exogenous type VII collagen did not alter LH3 expression in cultured RDEB keratinocytes and we show that RDEB patients receiving bone marrow transplantation who demonstrate significant increase in type VII collagen do not show increased levels of LH3 at the basement membrane. Our data report a direct link between LH3 and endogenous type VII collagen expression concluding that reduction of LH3 at the basement membrane in patients with RDEB will likely have significant implications for disease progression and therapeutic intervention
Genetic variation at CHRNA5-CHRNA3-CHRNB4 interacts with smoking status to influence body mass index
Background Cigarette smoking is associated with lower body mass index (BMI), and a commonly cited reason for unwillingness to quit smoking is a concern about weight gain. Common variation in the CHRNA5-CHRNA3-CHRNB4 gene region (chromosome 15q25) is robustly associated with smoking quantity in smokers, but its association with BMI is unknown. We hypothesized that genotype would accurately reflect smoking exposure and that, if smoking were causally related to weight, it would be associated with BMI in smokers, but not in never smokers. Methods We stratified nine European study samples by smoking status and, in each stratum, analysed the association between genotype of the 15q25 SNP, rs1051730, and BMI. We meta-analysed the results (n = 24 198) and then tested for a genotype × smoking status interaction. Results There was no evidence of association between BMI and genotype in the never smokers {difference per T-allele: 0.05 kg/m2 [95% confidence interval (95% CI): −0.05 to 0.18]; P = 0.25}. However, in ever smokers, each additional smoking-related T-allele was associated with a 0.23 kg/m2 (95% CI: 0.13-0.31) lower BMI (P = 8 × 10−6). The effect size was larger in current [0.33 kg/m2 lower BMI per T-allele (95% CI: 0.18-0.48); P = 6 × 10−5], than in former smokers [0.16 kg/m2 (95% CI: 0.03-0.29); P = 0.01]. There was strong evidence of genotype × smoking interaction (P = 0.0001). Conclusions Smoking status modifies the association between the 15q25 variant and BMI, which strengthens evidence that smoking exposure is causally associated with reduced BMI. Smoking cessation initiatives might be more successful if they include support to maintain a healthy BM
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