Increased GABAA Receptor ε-Subunit Expression on Ventral Respiratory Column Neurons Protects Breathing during Pregnancy

Written by on January 31, 2012 – 10:00 pm -

by Keith B. Hengen, Nathan R. Nelson, Kyle M. Stang, Stephen M. Johnson, Stephanie M. Crader, Jyoti J. Watters, Gordon S. Mitchell, Mary Behan

GABAergic signaling is essential for proper respiratory function. Potentiation of this signaling with allosteric modulators such as anesthetics, barbiturates, and neurosteroids can lead to respiratory arrest. Paradoxically, pregnant animals continue to breathe normally despite nearly 100-fold increases in circulating neurosteroids. ε subunit-containing GABAARs are insensitive to positive allosteric modulation, thus we hypothesized that pregnant rats increase ε subunit-containing GABAAR expression on brainstem neurons of the ventral respiratory column (VRC). In vivo, pregnancy rendered respiratory motor output insensitive to otherwise lethal doses of pentobarbital, a barbiturate previously used to categorize the ε subunit. Using electrode array recordings in vitro, we demonstrated that putative respiratory neurons of the preBötzinger Complex (preBötC) were also rendered insensitive to the effects of pentobarbital during pregnancy, but unit activity in the VRC was rapidly inhibited by the GABAAR agonist, muscimol. VRC unit activity from virgin and post-partum females was potently inhibited by both pentobarbital and muscimol. Brainstem ε subunit mRNA and protein levels were increased in pregnant rats, and GABAAR ε subunit expression co-localized with a marker of rhythm generating neurons (neurokinin 1 receptors) in the preBötC. These data support the hypothesis that pregnancy renders respiratory motor output and respiratory neuron activity insensitive to barbiturates, most likely via increased ε subunit-containing GABAAR expression on respiratory rhythm-generating neurons. Increased ε subunit expression may be critical to preserve respiratory function (and life) despite increased neurosteroid levels during pregnancy.

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The Risk of Stroke after Percutaneous Vertebroplasty for Osteoporosis: A Population-Based Cohort Study

Written by on January 31, 2012 – 10:00 pm -

by Ching-Lan Wu, Jau-Ching Wu, Wen-Cheng Huang, Hung-Ta H. Wu, Hong-Jen Chiou, Laura Liu, Yu-Chun Chen, Tzeng-Ji Chen, Henrich Cheng, Cheng-Yen Chang

Purpose

To investigate the incidence and risk of stroke after percutaneous vertebroplasty in patients with osteoporosis.

Methods

A group of 334 patients with osteoporosis, and who underwent percutaneous vertebroplasty during the study period, was compared to 1,655 age-, sex- and propensity score-matched patients who did not undergo vertebroplasty. All demographic covariates and co-morbidities were deliberately matched between the two groups to avoid selection bias. Every subject was followed-up for up to five years for stroke. Adjustments using a Cox regression model and Kaplan-Meier analyses were conducted.

Results

A total of 1,989 osteoporotic patients were followed up for 3,760.13 person-years. Overall, the incidence rates of any stroke, hemorrhagic stroke and ischemic stroke were 22.6, 4.2 and 19.6 per 1,000 person-years, respectively. Patients who underwent vertebroplasty were not more likely to have any stroke (crude hazard ratio = 1.13, p = 0.693), hemorrhagic stroke (HR = 2.21, p = 0.170), or ischemic stroke (HR = 0.96, p = 0.90). After adjusting for demographics, co-morbidities and medications, the vertebroplasty group had no significant difference with the comparison group in terms of any, hemorrhagic and ischemic strokes (adjusted HR = 1.22, 3.17, and 0.96, p = 0.518, 0.055, and 0.91, respectively).

Conclusions

Osteoporotic patients who undergo percutaneous vertebroplasty are not at higher risk of any stroke in the next five years after the procedure.


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Novel, Objective, Multivariate Biomarkers Composed of Plasma Amino Acid Profiles for the Diagnosis and Assessment of Inflammatory Bowel Disease

Written by on January 31, 2012 – 10:00 pm -

by Tadakazu Hisamatsu, Susumu Okamoto, Masaki Hashimoto, Takahiko Muramatsu, Ayatoshi Andou, Michihide Uo, Mina T. Kitazume, Katsuyoshi Matsuoka, Tomoharu Yajima, Nagamu Inoue, Takanori Kanai, Haruhiko Ogata, Yasushi Iwao, Minoru Yamakado, Ryosei Sakai, Nobukazu Ono, Toshihiko Ando, Manabu Suzuki, Toshifumi Hibi

Background

Inflammatory bowel disease (IBD) is a chronic intestinal disorder that is associated with a limited number of clinical biomarkers. In order to facilitate the diagnosis of IBD and assess its disease activity, we investigated the potential of novel multivariate indexes using statistical modeling of plasma amino acid concentrations (aminogram).

Methodology and Principal Findings

We measured fasting plasma aminograms in 387 IBD patients (Crohn's disease (CD), n = 165; ulcerative colitis (UC), n = 222) and 210 healthy controls. Based on Fisher linear classifiers, multivariate indexes were developed from the aminogram in discovery samples (CD, n = 102; UC, n = 102; age and sex-matched healthy controls, n = 102) and internally validated. The indexes were used to discriminate between CD or UC patients and healthy controls, as well as between patients with active disease and those in remission. We assessed index performances using the area under the curve of the receiver operating characteristic (ROC AUC). We observed significant alterations to the plasma aminogram, including histidine and tryptophan. The multivariate indexes established from plasma aminograms were able to distinguish CD or UC patients from healthy controls with ROC AUCs of 0.940 (95% confidence interval (CI): 0.898–0.983) and 0.894 (95%CI: 0.853–0.935), respectively in validation samples (CD, n = 63; UC, n = 120; healthy controls, n = 108). In addition, other indexes appeared to be a measure of disease activity. These indexes distinguished active CD or UC patients from each remission patients with ROC AUCs of 0.894 (95%CI: 0.853–0.935) and 0.849 (95%CI: 0.770–0.928), and correlated with clinical disease activity indexes for CD (rs = 0.592, 95%CI: 0.385–0.742, p<0.001) or UC (rs = 0.598, 95%CI: 0.452–0.713, p<0.001), respectively.

Conclusions and Significance

In this study, we demonstrated that established multivariate indexes composed of plasma amino acid profiles can serve as novel, non-invasive, objective biomarkers for the diagnosis and monitoring of IBD, providing us with new insights into the pathophysiology of the disease.


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A Role for VEGFR2 Activation in Endothelial Responses Caused by Barrier Disruptive OxPAPC Concentrations

Written by on January 31, 2012 – 10:00 pm -

by Anna A. Birukova, Sangderk Lee, Vitaliy Starosta, Tinghuai Wu, Tiffany Ho, Jin Kim, Judith A. Berliner, Konstantin G. Birukov

Introduction

Oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (OxPAPC) differentially modulate endothelial cell (EC) barrier function in a dose-dependent fashion. Vascular endothelial growth factor receptor-2 (VEGFR2) is involved in the OxPAPC-induced EC inflammatory activation. This study examined a role of VEGFR2 in barrier dysfunction caused by high concentrations of OxPAPC and evaluated downstream signaling mechanisms resulting from the effect of OxPAPC in EC from pulmonary and systemic circulation.

Methods

EC monolayer permeability in human pulmonary artery endothelial cells (HPAEC) and human aortic endothelial cells (HAEC) was monitored by changes in transendothelial electrical resistance (TER) across EC monolayers. Actin cytoskeleton was examined by immunostaining with Texas Red labeled phalloidin. Phosphorylation of myosin light chains (MLC) and VE-Cadherin was examined by Western blot and immunofluorescence techniques. The role of VEGFR2 in OxPAPC-induced permeability and cytoskeletal arrangement were determined using siRNA-induced VEGFR2 knockdown.

Results

Low OxPAPC concentrations (5–20 µg/ml) induced a barrier protective response in both HPAEC and HAEC, while high OxPAPC concentrations (50–100 µg/ml) caused a rapid increase in permeability ; actin stress fiber formation and increased MLC phosphorylation were observed as early as 30 min after treatment. VEGFR2 knockdown dramatically decreased the amount of MLC phosphorylation and stress fiber formation caused by high OxPAPC concentrations with modest effects on the amount of VE-cadherin phosphorylation at Y731. We present evidence that activation of Rho is involved in the OxPAPC/VEGFR2 mechanism of EC permeability induced by high OxPAPC concentrations. Knockdown of VEGFR2 did not rescue the early drop in TER but prevented further development of OxPAPC-induced barrier dysfunction.

Conclusions

This study shows that VEGFR2 is involved in the delayed phase of EC barrier dysfunction caused by high OxPAPC concentrations and contributes to stress fiber formation and increased MLC phosphorylation.


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Early Cell Death Detection with Digital Holographic Microscopy

Written by on January 31, 2012 – 10:00 pm -

by Nicolas Pavillon, Jonas Kühn, Corinne Moratal, Pascal Jourdain, Christian Depeursinge, Pierre J. Magistretti, Pierre Marquet

Background

Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM) dedicated to early and label-free detection of cell death.

Methods and Findings

We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability.

Conclusions

The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.


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Increased Inter-Colony Fusion Rates Are Associated with Reduced COI Haplotype Diversity in an Invasive Colonial Ascidian Didemnum vexillum

Written by on January 31, 2012 – 10:00 pm -

by Kirsty F. Smith, Lauren Stefaniak, Yasunori Saito, Chrissen E. C. Gemmill, S. Craig Cary, Andrew E. Fidler

Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species.

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A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia

Written by on January 31, 2012 – 10:00 pm -

by Casey M. Holliday, Nicholas M. Gardner

Crocodyliforms were one of the most successful groups of Mesozoic tetrapods, radiating into terrestrial, semiaquatic and marine environments, while occupying numerous trophic niches, including carnivorous, insectivorous, herbivorous, and piscivorous species. Among these taxa were the enigmatic, poorly represented flat-headed crocodyliforms from the late Cretaceous of northern Africa. Here we report a new, giant crocodyliform from the early Late Cretaceous (Cenomanian) Kem Kem Formation of Morocco. Represented by a partial braincase, the taxon has an extremely long, flat skull with large jaw and craniocervical muscles. The skull roof is ridged and ornamented with a broad, rough boss surrounded by significant vascular impressions, likely forming an integumentary structure unique among crocodyliforms. Size estimates using endocranial volume indicate the specimen was very large. The taxon possesses robust laterosphenoids with laterally oriented capitate processes and isolated epipterygoids, features allying it with derived eusuchians. Phylogenetic analysis finds the taxon to be a derived eusuchian and sister taxon to Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from the Bahariya formation. This clade forms the sister clade of crown-group Crocodylia, making these taxa the earliest eusuchian crocodyliforms known from Africa. These results shift phylogenetic and biogeographical hypotheses on the origin of modern crocodylians towards the circum-Tethyean region and provide important new data on eusuchian morphology and evolution.

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Primary Xenografts of Human Prostate Tissue as a Model to Study Angiogenesis Induced by Reactive Stroma

Written by on January 31, 2012 – 10:00 pm -

by Viviana P. Montecinos, Alejandro Godoy, Jennifer Hinklin, R. Robert Vethanayagam, Gary J. Smith

Characterization of the mechanism(s) of androgen-driven human angiogenesis could have significant implications for modeling new forms of anti-angiogenic therapies for CaP and for developing targeted adjuvant therapies to improve efficacy of androgen-deprivation therapy. However, models of angiogenesis by human endothelial cells localized within an intact human prostate tissue architecture are until now extremely limited. This report characterizes the burst of angiogenesis by endogenous human blood vessels in primary xenografts of fresh surgical specimens of benign prostate or prostate cancer (CaP) tissue that occurs between Days 6–14 after transplantation into SCID mice pre-implanted with testosterone pellets. The wave of human angiogenesis was preceded by androgen-mediated up-regulation of VEGF-A expression in the stromal compartment. The neo-vessel network anastomosed to the host mouse vascular system between Days 6–10 post-transplantation, the angiogenic response ceased by Day 15, and by Day 30 the vasculature had matured and stabilized, as indicated by a lack of leakage of serum components into the interstitial tissue space and by association of nascent endothelial cells with mural cells/pericytes. The angiogenic wave was concurrent with the appearance of a reactive stroma phenotype, as determined by staining for α-SMA, Vimentin, Tenascin, Calponin, Desmin and Masson's trichrome, but the reactive stroma phenotype appeared to be largely independent of androgen availability. Transplantation-induced angiogenesis by endogenous human endothelial cells present in primary xenografts of benign and malignant human prostate tissue was preceded by induction of androgen-driven expression of VEGF by the prostate stroma, and was concurrent with and the appearance of a reactive stroma phenotype. Androgen-modulated expression of VEGF-A appeared to be a causal regulator of angiogenesis, and possibly of stromal activation, in human prostate xenografts.

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Defining Plasmodium falciparum Treatment in South West Asia: A Randomized Trial Comparing Artesunate or Primaquine Combined with Chloroquine or SP

Written by on January 31, 2012 – 10:00 pm -

by Kate Kolaczinski, Toby Leslie, Iftikhar Ali, Naeem Durrani, Sue Lee, Marion Barends, Khalid Beshir, Rosalynn Ord, Rachel Hallett, Mark Rowland

Introduction

Antimalarial resistance has led to a global policy of artemisinin-based combination therapy. Despite growing resistance chloroquine (CQ) remained until recently the official first-line treatment for falciparum malaria in Pakistan, with sulfadoxine-pyrimethamine (SP) second-line. Co-treatment with the gametocytocidal primaquine (PQ) is recommended for transmission control in South Asia. The relative effect of artesunate (AS) or primaquine, as partner drugs, on clinical outcomes and gametocyte carriage in this setting were unknown.

Methods

A single-blinded, randomized trial among Afghan refugees in Pakistan compared six treatment arms: CQ; CQ+(single-dose)PQ; CQ+(3 d)AS; SP; SP+(single-dose)PQ, and SP+(3 d)AS. The objectives were to compare treatment failure rates and effect on gametocyte carriage, of CQ or SP monotherapy against the respective combinations (PQ or AS). Outcomes included trophozoite and gametocyte clearance (read by light microscopy), and clinical and parasitological failure.

Findings

A total of 308 (87%) patients completed the trial. Failure rates by day 28 were: CQ 55/68 (81%); CQ+AS 19/67 (28%), SP 4/41 (9.8%), SP+AS 1/41 (2.4%). The addition of PQ to CQ or SP did not affect failure rates (CQ+PQ 49/67 (73%) failed; SP+PQ 5/33 (16%) failed). AS was superior to PQ at clearing gametocytes; gametocytes were seen on d7 in 85% of CQ, 40% of CQ+PQ, 21% of CQ+AS, 91% of SP, 76% of SP+PQ and 23% of SP+AS treated patients. PQ was more effective at clearing older gametocyte infections whereas AS was more effective at preventing emergence of mature gametocytes, except in cases that recrudesced.

Conclusions

CQ is no longer appropriate by itself or in combination. These findings influenced the replacement of CQ with SP+AS for first-line treatment of uncomplicated falciparum malaria in the WHO Eastern Mediterranean Region. The threat of SP resistance remains as SP monotherapy is still common. Three day AS was superior to single-dose PQ for reducing gametocyte carriage.

Trial Registration

ClinicalTrials.gov bold>


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Homology Inference of Protein-Protein Interactions via Conserved Binding Sites

Written by on January 31, 2012 – 10:00 pm -

by Manoj Tyagi, Ratna R. Thangudu, Dachuan Zhang, Stephen H. Bryant, Thomas Madej, Anna R. Panchenko

The coverage and reliability of protein-protein interactions determined by high-throughput experiments still needs to be improved, especially for higher organisms, therefore the question persists, how interactions can be verified and predicted by computational approaches using available data on protein structural complexes. Recently we developed an approach called IBIS (Inferred Biomolecular Interaction Server) to predict and annotate protein-protein binding sites and interaction partners, which is based on the assumption that the structural location and sequence patterns of protein-protein binding sites are conserved between close homologs. In this study first we confirmed high accuracy of our method and found that its accuracy depends critically on the usage of all available data on structures of homologous complexes, compared to the approaches where only a non-redundant set of complexes is employed. Second we showed that there exists a trade-off between specificity and sensitivity if we employ in the prediction only evolutionarily conserved binding site clusters or clusters supported by only one observation (singletons). Finally we addressed the question of identifying the biologically relevant interactions using the homology inference approach and demonstrated that a large majority of crystal packing interactions can be correctly identified and filtered by our algorithm. At the same time, about half of biological interfaces that are not present in the protein crystallographic asymmetric unit can be reconstructed by IBIS from homologous complexes without the prior knowledge of crystal parameters of the query protein.

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Boolean Models of Biosurfactants Production in Pseudomonas fluorescens

Written by on January 31, 2012 – 10:00 pm -

by Adrien Richard, Gaelle Rossignol, Jean-Paul Comet, Gilles Bernot, Jannine Guespin-Michel, Annabelle Merieau

Cyclolipopeptides (CLPs) are biosurfactants produced by numerous Pseudomonas fluorescens strains. CLP production is known to be regulated at least by the GacA/GacS two-component pathway, but the full regulatory network is yet largely unknown. In the clinical strain MFN1032, CLP production is abolished by a mutation in the phospholipase C gene () and not restored by complementation. Their production is also subject to phenotypic variation. We used a modelling approach with Boolean networks, which takes into account all these observations concerning CLP production without any assumption on the topology of the considered network. Intensive computation yielded numerous models that satisfy these properties. All models minimizing the number of components point to a bistability in CLP production, which requires the presence of a yet unknown key self-inducible regulator. Furthermore, all suggest that a set of yet unexplained phenotypic variants might also be due to this epigenetic switch. The simplest of these Boolean networks was used to propose a biological regulatory network for CLP production. This modelling approach has allowed a possible regulation to be unravelled and an unusual behaviour of CLP production in P. fluorescens to be explained.

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Ologs: A Categorical Framework for Knowledge Representation

Written by on January 31, 2012 – 10:00 pm -

by David I. Spivak, Robert E. Kent

In this paper we introduce the olog, or ontology log, a category-theoretic model for knowledge representation (KR). Grounded in formal mathematics, ologs can be rigorously formulated and cross-compared in ways that other KR models (such as semantic networks) cannot. An olog is similar to a relational database schema; in fact an olog can serve as a data repository if desired. Unlike database schemas, which are generally difficult to create or modify, ologs are designed to be user-friendly enough that authoring or reconfiguring an olog is a matter of course rather than a difficult chore. It is hoped that learning to author ologs is much simpler than learning a database definition language, despite their similarity. We describe ologs carefully and illustrate with many examples. As an application we show that any primitive recursive function can be described by an olog. We also show that ologs can be aligned or connected together into a larger network using functors. The various methods of information flow and institutions can then be used to integrate local and global world-views. We finish by providing several different avenues for future research.

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TBX21 and HLX1 Polymorphisms Influence Cytokine Secretion at Birth

Written by on January 30, 2012 – 10:00 pm -

by Vera Isabel Casaca, Sabina Illi, Kathrin Suttner, Isolde Schleich, Nikolaus Ballenberger, Elizabeth Klucker, Elif Turan, Erika von Mutius, Michael Kabesch, Bianca Schaub

Background

TBX21 (T cell specific T-box transcription factor) and HLX1 (H.20-like homeobox 1) are crucial transcription factors of TH1-cells, inducing their differentiation and suppressing TH2 commitment, particularly important for early life immune development. This study investigated the influence of TBX21 and HLX1 single nucleotide polymorphisms (SNPs), which have previously been shown to be associated with asthma, on TH1/TH2 lineage cytokines at birth.

Methods and Findings

Cord blood mononuclear cells (CBMCs) of 200 neonates were genotyped for two TBX21 and three HLX1 SNPs. CBMCs were stimulated with innate (Lipid A, LpA; Peptidoglycan, Ppg), adaptive stimuli (house dust mite Dermatophagoides pteronyssinus 1, Derp1) or mitogen (phytohemagglutinin, PHA). Cytokines, T-cells and mRNA expression of TH1/TH2-related genes were assessed. Atopic diseases during the first 3 years of life were assessed by questionnaire answered by the parents.Carriers of TBX21 promoter SNP rs17250932 and HLX1 promoter SNP rs2738751 showed reduced or trendwise reduced (p≤0.07) IL-5, IL-13 and TNF-α secretion after LpA-stimulation. Carriers of HLX1 SNP rs2738751 had lower IL-13 levels following Ppg-stimulation (p = 0.08). Carriers of HLX1 exon 1 SNP rs12141189 showed increased IL-5 (LpA, p = 0.007; Ppg, p = 0.10), trendwise increased IL-13 (LpA), higher GM-CSF (LpA/Ppg, p≤0.05) and trendwise decreased IFN-γ secretion (Derp1+LpA-stimulation, p = 0.1). Homozygous carriers of HLX1 promoter SNP rs3806325 showed increased IL-13 and IL-6 (unstimulated, p≤0.03). In carriers of TBX21 intron 3 SNP rs11079788 no differences in cytokine secretion were observed. mRNA expression of TH1/TH2-related genes partly correlated with cytokines at protein level. TBX21 SNP rs11079788 carriers developed less symptoms of atopic dermatitis at 3 years of age (p = 0.03).

Conclusions

Polymorphisms in TBX21 and HLX1 influenced primarily IL-5 and IL-13 secretion after LpA-stimulation in cord blood suggesting that genetic variations in the transcription factors essential for the TH1-pathway may contribute to modified TH2-immune responses already early in life. Further follow-up of the cohort is required to study the polymorphisms' relevance for immune-mediated diseases such as childhood asthma.


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Quality Control and Performance of HIV Rapid Tests in a Microbicide Clinical Trial in Rural KwaZulu-Natal

Written by on January 30, 2012 – 10:00 pm -

by Nina von Knorring, Mitzy Gafos, Motsei Ramokonupi, Ute Jentsch, the MDP Team

Background

Quality control (QC) and evaluation of HIV rapid test procedures are an important aspect of HIV prevention trials. We describe QC and performance of two rapid tests, Determine™ and Uni-Gold™ used in a microbicide clinical trial in rural KwaZulu-Natal, South Africa.

Methods/Results

Internal QC of both HIV rapid tests was conducted at the trial site using a Uni-Gold control kit (Uni-Gold™Recombigen® HIV). Both assays produced the expected results for a total of 4637 QC tests. Study participants were tested for HIV at screening and, if enrolled, at regular time points throughout the study. Positive or discordant results were confirmed by a double HIV immunoassay testing strategy at a local laboratory. Overall, 15292 HIV rapid test were performed. Sensitivity and specificity of Determine was 98.95% (95% CI: 97.72–99.61) and 99.83% (95% CI: 99.70–99.91) respectively [positive predictive value (PPV) 97.91% (95% CI: 96.38–98.92)], for Uni-Gold it was 99.30% (95% CI: 98.21–99.81) and 99.96% (95% CI: 99.88–99.99) respectively [PPV 99.47% (95% CI: 98.46–99.89)].

Conclusions

The results suggest that a Uni-Gold control kit can be used for internal QC of both Uni-Gold and the HIV-1 component of the Determine rapid tests. Both rapid tests performed proficiently in the trial population.


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Seeing Emotion with Your Ears: Emotional Prosody Implicitly Guides Visual Attention to Faces

Written by on January 30, 2012 – 10:00 pm -

by Simon Rigoulot, Marc D. Pell

Interpersonal communication involves the processing of multimodal emotional cues, particularly facial expressions (visual modality) and emotional speech prosody (auditory modality) which can interact during information processing. Here, we investigated whether the implicit processing of emotional prosody systematically influences gaze behavior to facial expressions of emotion. We analyzed the eye movements of 31 participants as they scanned a visual array of four emotional faces portraying fear, anger, happiness, and neutrality, while listening to an emotionally-inflected pseudo-utterance (Someone migged the pazing) uttered in a congruent or incongruent tone. Participants heard the emotional utterance during the first 1250 milliseconds of a five-second visual array and then performed an immediate recall decision about the face they had just seen. The frequency and duration of first saccades and of total looks in three temporal windows ([0–1250 ms], [1250–2500 ms], [2500–5000 ms]) were analyzed according to the emotional content of faces and voices. Results showed that participants looked longer and more frequently at faces that matched the prosody in all three time windows (emotion congruency effect), although this effect was often emotion-specific (with greatest effects for fear). Effects of prosody on visual attention to faces persisted over time and could be detected long after the auditory information was no longer present. These data imply that emotional prosody is processed automatically during communication and that these cues play a critical role in how humans respond to related visual cues in the environment, such as facial expressions.

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