436 research outputs found
Mandarin speech perception in combined electric and acoustic stimulation.
For deaf individuals with residual low-frequency acoustic hearing, combined use of a cochlear implant (CI) and hearing aid (HA) typically provides better speech understanding than with either device alone. Because of coarse spectral resolution, CIs do not provide fundamental frequency (F0) information that contributes to understanding of tonal languages such as Mandarin Chinese. The HA can provide good representation of F0 and, depending on the range of aided acoustic hearing, first and second formant (F1 and F2) information. In this study, Mandarin tone, vowel, and consonant recognition in quiet and noise was measured in 12 adult Mandarin-speaking bimodal listeners with the CI-only and with the CI+HA. Tone recognition was significantly better with the CI+HA in noise, but not in quiet. Vowel recognition was significantly better with the CI+HA in quiet, but not in noise. There was no significant difference in consonant recognition between the CI-only and the CI+HA in quiet or in noise. There was a wide range in bimodal benefit, with improvements often greater than 20 percentage points in some tests and conditions. The bimodal benefit was compared to CI subjects' HA-aided pure-tone average (PTA) thresholds between 250 and 2000 Hz; subjects were divided into two groups: "better" PTA (<50 dB HL) or "poorer" PTA (>50 dB HL). The bimodal benefit differed significantly between groups only for consonant recognition. The bimodal benefit for tone recognition in quiet was significantly correlated with CI experience, suggesting that bimodal CI users learn to better combine low-frequency spectro-temporal information from acoustic hearing with temporal envelope information from electric hearing. Given the small number of subjects in this study (n = 12), further research with Chinese bimodal listeners may provide more information regarding the contribution of acoustic and electric hearing to tonal language perception
A novel polar space random field model for the detection of glandular structures
In this paper, we propose a novel method to detect glandular structures in microscopic images of human tissue. We first convert the image from Cartesian space to polar space and then introduce a novel random field model to locate the possible boundary of a gland. Next, we develop a visual feature-based support vector regressor to verify if the detected contour corresponds to a true gland. And finally, we combine the outputs of the random field and the regressor to form the GlandVision algorithm for the detection of glandular structures. Our approach can not only detect the existence of the gland, but also can accurately locate it with pixel accuracy. In the experiments, we treat the task of detecting glandular structures as object (gland) detection and segmentation problems respectively. The results indicate that our new technique outperforms state-of-the-art computer vision algorithms in respective fields
Adult restoration of Shank3 expression rescues selective autistic-like phenotypes
Because autism spectrum disorders are neurodevelopmental disorders and patients typically display symptoms before the age of three, one of the key questions in autism research is whether the pathology is reversible in adults. Here we investigate the developmental requirement of Shank3 in mice, a prominent monogenic autism gene that is estimated to contribute to approximately 1% of all autism spectrum disorder cases. SHANK3 is a postsynaptic scaffold protein that regulates synaptic development, function and plasticity by orchestrating the assembly of post synaptic density macromolecular signalling complex. Disruptions of the Shank3 gene in mouse models have resulted in synaptic defects and autistic-like behaviours including anxiety, social interaction deficits, and repetitive behaviour. We generated a novel Shank3 conditional knock-in mouse model, and show that re-expression of the Shank3 gene in adult mice led to improvements in synaptic protein composition, spine density and neural function in the striatum. We also provide behavioural evidence that certain behavioural abnormalities including social interaction deficit and repetitive grooming behaviour could be rescued, while anxiety and motor coordination deficit could not be recovered in adulthood. Together, these results reveal the profound effect of post-developmental activation of Shank3 expression on neural function, and demonstrate a certain degree of continued plasticity in the adult diseased brain.National Institutes of Health (U.S.) (Grant R01MH097104
Shank3 mutant mice display autistic-like behaviours and striatal dysfunction
Autism spectrum disorders (ASDs) comprise a range of disorders that share a core of neurobehavioural deficits characterized by widespread abnormalities in social interactions, deficits in communication as well as restricted interests and repetitive behaviours. The neurological basis and circuitry mechanisms underlying these abnormal behaviours are poorly understood. SHANK3 is a postsynaptic protein, whose disruption at the genetic level is thought to be responsible for the development of 22q13 deletion syndrome (Phelan–McDermid syndrome) and other non-syndromic ASDs. Here we show that mice with Shank3 gene deletions exhibit self-injurious repetitive grooming and deficits in social interaction. Cellular, electrophysiological and biochemical analyses uncovered defects at striatal synapses and cortico-striatal circuits in Shank3 mutant mice. Our findings demonstrate a critical role for SHANK3 in the normal development of neuronal connectivity and establish causality between a disruption in the Shank3 gene and the genesis of autistic-like behaviours in mice.National Institute of Mental Health (U.S.) (NIMH/NIH (R01MH081201))Hartwell Foundation (Hartwell Individual Biomedical Research Award)Simons Foundation (Autism Research Initiative (SFARI) grant Award)Brain and Behavior Research Foundation (NARSAD Young Investigator Award)National Institutes of Health (U.S.) (Ruth L. Kirschstein National Research Service Award (F32MH084460))National Institutes of Health (U.S.) (NIH grant (R03MH085224))Fundação para a Ciência e a Tecnologia (SFRH/BD/15231/2004)Fundação para a Ciência e a Tecnologia (SFRH/BD/15855/2005)Instituto Gulbenkian de Ciência (“Programa Gulbenkian de Doutoramento em Biomedicina” (PGDB, Oeiras, Portugal))University of Coimbra. Center for Neuroscience and Cell Biology (“Programa Doutoral em Biologia Experimental e Biomedicina” (CNC, Coimbra, Portugal)
Gender-based clinical study on the association of cognitive impairment with drinking and smoking
Purpose: To evaluate the relationship between alcohol consumption and cigarette smoking among the elderly population of a Chinese city with a risk of developing cognitive decline and dementia.Methods: In this study, 1687 participants from the suburban town of Yanliang in Xi'an Sub-province, Shanxi Province, China in the age group of 60 - 65 years and who have not develop cognitive decline were assessed over a 6-year period. The study involved the evaluation of gender-based effect on alcohol consumption and smoking cigarette and its impact on cognitive functions.Results: The study observed that smokers have a higher risk of cognitive decline than non-smokers (odds ratio = 1.51; 95 % CI = (1.07 – 2.11). Interestingly, the odds ratio of the smokers among the female subjects was 1.54; 95 % CI (1.02 - 2.49) compared to female non-smokers. Moreover, a dosedependent relationship was observed for those female smoker with higher pack-years compared to nonsmokers (p = 0.003). On the other hand, regular alcohol consumption also increased the possibility of dementia and cognitive decline (odds ratio = 1.69; CI at 95 % = (1.03 – 2.75), hence a dose-dependent relationship was observed between male users (p = 0.042).Conclusion: The results suggest that alcohol consumption and smoking are linked with cognitive decline among the female subjects in the age group of 60 – 65 years. Thus, the relationship between these factors is characterized by gender difference which may be due to female sex hormones.Keywords: Cognitive health, Alcohol consumptions, Smoking, Elderly populatio
CXCR5+PD-1+ follicular helper CD8 T cells control B cell tolerance
Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4+ T follicular helper (Tfh) cells are the main subset regulating autoreactive B cells. Here we report a CXCR5+PD1+ Tfh subset of CD8+ T cells whose development and function are negatively modulated by Stat5. These CD8+ Tfh cells regulate the germinal center B cell response and control autoantibody production, as deficiency of Stat5 in CD8 T cells leads to an increase of CD8+ Tfh cells, resulting in the breakdown of B cell tolerance and concomitant autoantibody production. CD8+ Tfh cells share similar gene signatures with CD4+ Tfh, and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study thus highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance
Mandarin Speech Perception in Combined Electric and Acoustic Stimulation
For deaf individuals with residual low-frequency acoustic hearing, combined use of a cochlear implant (CI) and hearing aid (HA) typically provides better speech understanding than with either device alone. Because of coarse spectral resolution, CIs do not provide fundamental frequency (F0) information that contributes to understanding of tonal languages such as Mandarin Chinese. The HA can provide good representation of F0 and, depending on the range of aided acoustic hearing, first and second formant (F1 and F2) information. In this study, Mandarin tone, vowel, and consonant recognition in quiet and noise was measured in 12 adult Mandarin-speaking bimodal listeners with the CI-only and with the CI+HA. Tone recognition was significantly better with the CI+HA in noise, but not in quiet. Vowel recognition was significantly better with the CI+HA in quiet, but not in noise. There was no significant difference in consonant recognition between the CI-only and the CI+HA in quiet or in noise. There was a wide range in bimodal benefit, with improvements often greater than 20 percentage points in some tests and conditions. The bimodal benefit was compared to CI subjects' HA-aided pure-tone average (PTA) thresholds between 250 and 2000 Hz; subjects were divided into two groups: "better" PTA (<50 dB HL) or "poorer" PTA (>50 dB HL). The bimodal benefit differed significantly between groups only for consonant recognition. The bimodal benefit for tone recognition in quiet was significantly correlated with CI experience, suggesting that bimodal CI users learn to better combine low-frequency spectro-temporal information from acoustic hearing with temporal envelope information from electric hearing. Given the small number of subjects in this study (n = 12), further research with Chinese bimodal listeners may provide more information regarding the contribution of acoustic and electric hearing to tonal language perception
Striatopallidal dysfunction underlies repetitive behavior in Shank3-deficient model of autism
The postsynaptic scaffolding protein SH3 and multiple ankyrin repeat domains 3 (SHANK3) is critical for the development and function of glutamatergic synapses. Disruption of the SHANK3-encoding gene has been strongly implicated as a monogenic cause of autism, and Shank3 mutant mice show repetitive grooming and social interaction deficits. Although basal ganglia dysfunction has been proposed to underlie repetitive behaviors, few studies have provided direct evidence to support this notion and the exact cellular mechanisms remain largely unknown. Here, we utilized the Shank3B mutant mouse model of autism to investigate how Shank3 mutation may differentially affect striatonigral (direct pathway) and striatopallidal (indirect pathway) medium spiny neurons (MSNs) and its relevance to repetitive grooming behavior in Shank3B mutant mice. We found that Shank3 deletion preferentially affects synapses onto striatopallidal MSNs. Striatopallidal MSNs showed profound defects, including alterations in synaptic transmission, synaptic plasticity, and spine density. Importantly, the repetitive grooming behavior was rescued by selectively enhancing the striatopallidal MSN activity via a Gq-coupled human M3 muscarinic receptor (hM3Dq), a type of designer receptors exclusively activated by designer drugs (DREADD). Our findings directly demonstrate the existence of distinct changes between 2 striatal pathways in a mouse model of autism and indicate that the indirect striatal pathway disruption might play a causative role in repetitive behavior of Shank3B mutant mice.National Institute of Mental Health (U.S.) (Grant 5R01MH097104
High Density Lipoprotein Protects Mesenchymal Stem Cells from Oxidative Stress-Induced Apoptosis via Activation of the PI3K/Akt Pathway and Suppression of Reactive Oxygen Species
The therapeutic effect of transplantation of mesenchymal stem cells (MSCs) in myocardial infarction (MI) appears to be limited by poor cell viability in the injured tissue, which is a consequence of oxidative stress and pro-apoptotic factors. High density lipoprotein (HDL) reverses cholesterol transport and has anti-oxidative and anti-apoptotic properties. We, therefore, investigated whether HDL could protect MSCs from oxidative stress-induced apoptosis. MSCs derived from the bone marrow of rats were pre-incubated with or without HDL, and then were exposed to hydrogen peroxide (H2O2) in vitro, or were transplanted into experimentally infarcted hearts of rats in vivo. Pre-incubation of MSCs with HDL increased cell viability, reduced apoptotic indices and resulted in parallel decreases in reactive oxygen species (ROS) in comparison with control MSCs. Each of the beneficial effects of HDL on MSCs was attenuated by inhibiting the PI3K/Akt pathway. Preconditioning with HDL resulted in higher MSC survival rates, improved cardiac remodeling and better myocardial function than in the MSC control group. Collectively, these results suggest that HDL may protect against H2O2-induced apoptosis in MSCs through activation of a PI3K/Akt pathway, and by suppressing the production of ROS
Genome-Wide Expression Analysis in Down Syndrome: Insight into Immunodeficiency
Down syndrome (DS) is caused by triplication of Human chromosome 21 (Hsa21) and associated with an array of deleterious phenotypes, including mental retardation, heart defects and immunodeficiency. Genome-wide expression patterns of uncultured peripheral blood cells are useful to understanding of DS-associated immune dysfunction. We used a Human Exon microarray to characterize gene expression in uncultured peripheral blood cells derived from DS individuals and age-matched controls from two age groups: neonate (N) and child (C). A total of 174 transcript clusters (gene-level) with eight located on Hsa21 in N group and 383 transcript clusters including 56 on Hsa21 in C group were significantly dysregulated in DS individuals. Microarray data were validated by quantitative polymerase chain reaction. Functional analysis revealed that the dysregulated genes in DS were significantly enriched in two and six KEGG pathways in N and C group, respectively. These pathways included leukocyte trans-endothelial migration, B cell receptor signaling pathway and primary immunodeficiency, etc., which causally implicated dysfunctional immunity in DS. Our results provided a comprehensive picture of gene expression patterns in DS at the two developmental stages and pointed towards candidate genes and molecular pathways potentially associated with the immune dysfunction in DS
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