Creating a spontaneous conversational speech corpus

Speech recognition and language analysis of spontaneous speech arising in naturally spoken conversations are becoming the subject of much research. However, there is a shortage of spontaneous speech corpora that are freely available for academics. We therefore undertook the building of a natural conversation speech database, recording over 200 hours of conversations in English by over 600 local university students. With few exceptions, the students used their own cell phones from their own rooms or homes to speak to one another, and they were permitted to speak on any topic they chose. Although they knew that they were being recorded and that they would receive a small payment, their conversations in the corpus are probably very close to being natural and spontaneous. This paper describes a detailed case study of the problems we faced and the methods we used to make the recordings and control the collection of these social science data on a limited budget.

Spontaneous intramedullary apoptosis is present in disorders other than myelodysplasia

Myelodysplastic syndrome (MDS) is a group of hematopoietic disorders characterized by peripheral cytopenias in the presence of normo- or hypercellular dysplastic marrow. It has been suggested that premature intramedullary apoptosis may contribute to this phenomenon. We used terminal dUTP nick-end labeling (TUNEL) of bone marrow biopsy specimens and cytocentrifuge preparations from patients with MDS and a variety of other hematopoietic disorders to determine whether there is increased intramedullary apoptosis in MDS and whether any such effect is specific to MDS. TUNEL labeling of bone marrow from 24 patients with MDS revealed significant positivity in 10 of 11 patients with refractory anemia (RA), five of seven with RA and excess of blasts (RAEB), all three patients with RAEB in transformation (RAEB-t), and all three patients with RA with ring sideroblasts (RARS). The percent of positive cells ranged from 5 to 50% but showed no apparent correlation with morphological subtype. In a series of 29 patients with acute leukemia, 17 showed significant positivity (13 of 13 with myeloid disease: three M1, seven M2, one M3, two M4; four of 16 patients with lymphoid disease: one Burkitt-type lymphoma, two null acute leukemia, and one common acute lymphoid leukemia). Intramedullary apoptosis was associated with myeloid or early committed progenitor cells and was highest in secondary acute myeloid leukemia (AML). Normal bone marrow samples from 12 individuals showed no evidence of apoptosis. Our results suggest that an increased level of intramedullary apoptosis is apparent in both patients with MDS and those with AML; those with secondary AML have the highest levels. The relative absence of such findings in lymphoid malignancy suggests that the apoptotic pathways are different in this lineage.

Selective extracellular vesicle-mediated export of an overlapping set of microRNAs from multiple cell types

Background: MicroRNAs (miRNAs) are a class of small RNA molecules that regulate expression of specific mRNA targets. They can be released from cells, often encapsulated within extracellular vesicles (EVs), and therefore have the potential to mediate intercellular communication. It has been suggested that certain miRNAs may be selectively exported, although the mechanism has yet to be identified. Manipulation of the miRNA content of EVs will be important for future therapeutic applications. We therefore wished to assess which endogenous miRNAs are enriched in EVs and how effectively an overexpressed miRNA would be exported.

Results: Small RNA libraries from HEK293T cells and vesicles before or after transfection with a vector for miR-146a overexpression were analysed by deep sequencing. A subset of miRNAs was found to be enriched in EVs; pathway analysis of their predicted target genes suggests a potential role in regulation of endocytosis. RT-qPCR in additional cell types and analysis of publicly available data revealed that many of these miRNAs tend to be widely preferentially exported. Whilst overexpressed miR-146a was highly enriched both in transfected cells and their EVs, the cellular:EV ratios of endogenous miRNAs were not grossly altered. MiR-451 was consistently the most highly exported miRNA in many different cell types. Intriguingly, Argonaute2 (Ago2) is required for miR-451 maturation and knock out of Ago2 has been shown to decrease expression of other preferentially exported miRNAs (eg miR-150 and miR-142-3p).

Conclusion: The global expression data provided by deep sequencing confirms that specific miRNAs are enriched in EVs released by HEK293T cells. Observation of similar patterns in a range of cell types suggests that a common mechanism for selective miRNA export may exist.

Spontaneous Attention to Faces in Asperger Sndrome using Ecologically Valid Static Stimuli

Previous eye tracking research on the allocation of attention to social information by individuals with autism spectrum disorders is equivocal and may be in part a consequence of variation in stimuli used between studies. The current study explored attention allocation to faces, and within faces,
by individuals with Asperger syndrome using a range of static stimuli where faces were either viewed in isolation or viewed in the context of a social scene. Results showed that faces were viewed typically by the individuals with Asperger syndrome when presented in isolation, but attention to the eyes was significantly diminished in comparison to age and IQ-matched typical viewers when faces were viewed as part of social scenes. We show that when using static stimuli, there is evidence of atypicality for individuals with Asperger syndrome depending on the extent of social context. Our findings shed light on the previous explanations of gaze behaviour that have emphasised the role of movement in atypicalities of social attention in autism spectrum disorders and highlight the importance of consideration of the realistic portrayal of social information for future studies.

Contribution of reverse Na+/Ca2+ exchange to spontaneous activity in interstitial cells of cajal in the rabbit urethra

Interstitial cells of Cajal (ICC) isolated from the rabbit urethra exhibit regular Ca2+ oscillations that are associated with spontaneous transient inward currents (STICs) recorded under voltage clamp. Their frequency is known to be very sensitive to external Ca2+ concentration but the mechanism of this has yet to be elucidated. In the present study experiments were performed to assess the role of Na+-Ca2+ exchange (NCX) in this process. Membrane currents were recorded using the patch clamp technique and measurements of intracellular Ca2+ were made using fast confocal microscopy. When reverse mode NCX was enhanced by decreasing the external Na+ concentration [Na+]o from 130 to 13 mM, the frequency of global Ca2+ oscillations and STICs increased. Conversely, inhibition of reverse mode NCX by KB-R7943 and SEA0400 decreased the frequency of Ca2+ oscillations and STICs. Application of caffeine (10 mM) and noradrenaline (10 microM) induced transient Ca2+-activated chloride currents (I(ClCa)) at -60 mV due to release of Ca2+ from ryanodine- and inositol trisphosphate (IP3)-sensitive Ca2+ stores, respectively, but these responses were not blocked by KB-R7943 or SEA0400 suggesting that neither drug blocked Ca2+-activated chloride channels or Ca2+ release from stores. Intact strips of rabbit urethra smooth muscle develop spontaneous myogenic tone. This tone was relaxed by application of SEA0400 in a concentration-dependent fashion. Finally, single cell RT-PCR experiments revealed that isolated ICC from the rabbit urethra only express the type 3 isoform of the Na+-Ca2+ exchanger (NCX3). These results suggest that frequency of spontaneous activity in urethral ICC can be modulated by Ca2+ entry via reverse NCX.

Demographic noise can lead to the spontaneous formation of species

When a collection of phenotypically diverse organisms compete with each other for limited resources, the population can evolve into tightly localised clusters. Past studies have neglected the effects of demographic noise and studied the population on a macroscopic scale, where cluster formation is found to depend on the shape of the curve describing the decline of competition strength with phenotypic distance. Here we show how including the effects of demographic noise leads to a radically different conclusion. Two situations are identified: a weak-noise regime in which the population exhibits patterns of fluctuation around the macroscopic description, and a strong-noise regime where clusters appear spontaneously even in the case that all organisms have equal fitness. editor's choice Copyright (C) EPLA, 2012

Functional expression of KCNQ (Kv7) channels in guinea-pig bladder smooth muscle and their contribution to spontaneous activity

Background and Purpose: The aim of the study was to determine whether KCNQ channels are functionally expressed in bladder smooth muscle cells (SMC) and to investigate their physiological significance in bladder contractility. 

Experimental Approach: KCNQ channels were examined at the genetic, protein, cellular and tissue level in guinea pig bladder smooth muscle using RT-PCR, immunofluorescence, patch-clamp electrophysiology, calcium imaging, detrusor strip myography, and a panel of KCNQ activators and inhibitors. 

Key Results: KCNQ subtypes 1-5 are expressed in bladder detrusor smooth muscle. Detrusor strips typically displayed TTX-insensitive myogenic spontaneous contractions that were increased in amplitude by the KCNQ channel inhibitors XE991, linopirdine or chromanol 293B. Contractility was inhibited by the KCNQ channel activators flupirtine or meclofenamic acid (MFA). The frequency of Ca2+-oscillations in SMC contained within bladder tissue sheets was increased by XE991. Outward currents in dispersed bladder SMC, recorded under conditions where BK and KATP currents were minimal, were significantly reduced by XE991, linopirdine, or chromanol, and enhanced by flupirtine or MFA. XE991 depolarized the cell membrane and could evoke transient depolarizations in quiescent cells. Flupirtine (20M) hyperpolarized the cell membrane with a simultaneous cessation of any spontaneous electrical activity. 

Conclusions and Implications: These novel findings reveal the role of KCNQ currents in the regulation of the resting membrane potential of detrusor SMC and their important physiological function in the control of spontaneous contractility in the guinea pig bladder.

Spontaneous and cued gaze-following in autism and Williams syndrome

Background: From a young age the typical development of social functioning relies upon the allocation of attention to socially relevant information, which in turn allows experience at processing such information and thus enhances social cognition. As such, research has attempted to identify the developmental processes that are derailed in some neuro-developmental disorders that impact upon social functioning. Williams syndrome (WS) and Autism are disorders of development that are characterized by atypical yet divergent social phenotypes and atypicalities of attention to people.

Methods: We used eye tracking to explore how individuals with WS and Autism attended to, and subsequently interpreted, an actor’s eye gaze cue within a social scene. Images were presented for three seconds, initially with an instruction simply to look at the picture. The images were then shown again, with the participant asked to identify the object being looked at. Allocation of eye-gaze in each condition was analyzed by ANOVA and accuracy of identification was compared with t-tests.

Results: Participants with WS allocated more gaze time to face and eyes than their matched controls both with and without being asked to identify the item being looked at; while participants with Autism spent less time on face and eyes in both conditions. When cued to follow gaze, participants with WS increased gaze to the correct targets, while those with Autism looked more at the face and eyes but did not increase gaze to the correct targets, while continuing to look much more than their controls at implausible targets. Both groups identified fewer objects than their controls.

Conclusions: The atypicalities found are likely to be entwined with the deficits shown in interpreting social cognitive cues from the images. WS and Autism are characterised by atypicalities of social attention that impact upon socio-cognitive expertise but importantly the type of atypicality is syndrome-specific.

Th1 not Th17 cells drive spontaneous MS-like disease despite a functional regulatory T cell response

Multiple sclerosis is considered a disease of complex autoimmune etiology, yet there remains a lack of consensus as to specific immune effector mechanisms. Recent analyses of experimental autoimmune encephalomyelitis, the common mouse model of multiple sclerosis, have investigated the relative contribution of Th1 and Th17 CD4 T cell subsets to initial autoimmune central nervous system (CNS) damage. However, inherent in these studies are biases influenced by the adjuvant and toxin needed to break self-tolerance. We investigated spontaneous CNS disease in a clinically relevant, humanized, T cell receptor transgenic mouse model. Mice develop spontaneous, ascending paralysis, allowing unbiased characterization of T cell immunity in an HLA-DR15-restricted T cell repertoire. Analysis of naturally progressing disease shows that IFN?(+) cells dominate disease initiation with IL-17(+) cells apparent in affected tissue only once disease is established. Tregs accumulate in the CNS but are ultimately ineffective at halting disease progression. However, ablation of Tregs causes profound acceleration of disease, with uncontrolled infiltration of lymphocytes into the CNS. This synchronous, severe disease allows characterization of the responses that are deregulated in exacerbated disease: the correlation is with increased CNS CD4 and CD8 IFN? responses. Recovery of the ablated Treg population halts ongoing disease progression and Tregs extracted from the central nervous system at peak disease are functionally competent to regulate myelin specific T cell responses. Thus, in a clinically relevant mouse model of MS, initial disease is IFN? driven and the enhanced central nervous system responses unleashed through Treg ablation comprise IFN? cytokine production by CD4 and CD8 cells, but not IL-17 responses.

Determination of Spontaneous Mutation Frequencies in Measles Virus under Nonselective Conditions

There is a paradox between the remarkable genetic stability of measles virus (MV) in the field and the high mutation rates implied by the frequency of the appearance of monoclonal antibody escape mutants generated when the virus is pressured to revert in vitro (S. J. Schrag, P. A. Rota, and W. J. Bellini, J. Virol. 73: 51-54, 1999). We established a highly sensitive assay to determine frequencies of various categories of mutations in large populations of wild-type and laboratory-adapted MVs using recombinant viruses containing an additional transcription unit (ATU) encoding enhanced green fluorescent protein (EGFP). Single and double mutations were made in the fluorophore of EGFP to ablate fluorescence. The frequencies of reversion mutants in the population were determined by measuring the appearance of fluorescence indicating a revertant virus. This allows mutation rates to be measured under nonselective conditions, as phenotypic reversion to fluorescence requires only either a single-or a double-nucleotide change and amino acid substitution, which does not affect the length of the nonessential reporter protein expressed from the ATU. Mutation rates in MV are the same for wild-type and laboratory-adapted viruses, and they are an order of magnitude lower than the previous measurement assessed under selective conditions. The actual mutation rate for MV is approximately 1.8 x 10(-6) per base per replication event. Copyright © 2013, American Society for Microbiology. All Rights Reserved.