3,624 research outputs found

    Sylvian fissure and parietal anatomy in children with autism spectrum disorder

    Get PDF
    Autism spectrum disorder (ASD) is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF) and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7–14 years), matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions.This study was supported by a program project grant from the National Institute on Deafness and Other Communication Disorders (U19 DC 03610), which is part of the NICHD/NIDCD funded Collaborative Programs on Excellence in Autism, as well as funding for the GCRC at Boston University School of Medicine (M01-RR0533). We thank all of our research assistants for help in collecting the data and Andrew Silver, Melanee Schuring, Danielle Delosh, and Jeremy Siegal for completing the total hemisphere measurements. We also extend our sincere gratitude to the children and families who participated in this study. (U19 DC 03610 - National Institute on Deafness and Other Communication Disorders; NICHD/NIDCD; M01-RR0533 - Boston University School of Medicine)Published versio

    Design and analysis of a beacon-less routing protocol for large volume content dissemination in vehicular ad hoc networks

    Get PDF
    Largevolumecontentdisseminationispursuedbythegrowingnumberofhighquality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well

    Characterization and Transplantation of Felid Spermatogonial Stem Cells

    Get PDF
    Spermatogonial stem cells (SSC) self-renew and differentiate into spermatozoa throughout the life of the male. SSC transplantation is a potential method for the propagation of genetically important males. These cells have been isolated in different mammalian species using specific cell surface markers, but not in felines. The goal of this study was to explore a relevant strategy for conservation of endangered felids by characterizing domestic cat (Felis catus) SSCs and assessing their ability for self-renewal after transplantation. Firstly, SSC and pluripotent surface markers, identified in non-feline species, were tested for expression in mixed germ cells from adults by immunocytochemistry and flow cytometry, with immunohistochemical confirmation of expression in prepubertal and adult testis tissue. Secondly, subpopulations were purified through fluorescence-activated cell sorting using spermatogonia-specific markers and molecularly characterized to ascertain levels of pluripotent transcription factors expressed in cat embryos. Thirdly, subpopulations of mixed germ cells and purified spermatogonial cells were transplanted to prepubertal cats to determine: 1) if SSCs capable of colonization were present, and 2) the value of using adolescent domestic cats without depletion of endogenous germ cells as recipients. Fourthly, various culture conditions were evaluated to identify proteins and factors required to maintain proliferation of cat SSCs. Lastly, adult lion testis tissue was characterized with the same surface markers, and mixed germ cells were transplanted to cat testes to evaluate the cat as a suitable host for lion SSC colonization and differentiation. Pluripotent surface markers were more reliable than the common SSC surface markers for isolating cat SSCs. Varying expression levels of pluripotent transcription factors between the different purified cell populations identified spermatogonial subpopulations. Cell purification was not necessary to colonize recipient testes, and transplantation validated the use of prepubertal males as recipients without depletion of endogenous cells. Unlike spermatogonia within mixed germ cells, purified spermatogonia were not maintained under various culture conditions; therefore, SSC culture conditions must be optimized. Similarities in the expression patterns of surface markers in lion and cat spermatogonia were revealed, and colonization of lion SSCs in cat testes provided further evidence of the domestic cat’s relevance as a model for exotic felid SSC transplantation

    Alcohol Clin Exp Res

    Get PDF
    BackgroundOur objective was to examine whether components of the neighborhood alcohol environment\ue2\u20ac\u201dliquor store, on-premise outlet, convenience store, and supermarket densities\ue2\u20ac\u201dare positively associated with at-risk alcohol consumption among African American drinkers.MethodsMultilevel cross-sectional sample of 321 African American women and men ages 21 to 65 years recruited from April 2002 to May 2003 from three community-based healthcare clinics in New Orleans, Louisiana, U.S.ResultsThe alcohol environment had a significant impact on at-risk alcohol consumption among African American drinkers, specifically liquor store density (adjusted OR = 3.11, 95% CI = 1.87, 11.07). Furthermore, the influence of the alcohol environment was much stronger for African American female drinkers (adjusted OR = 6.96, 95% CI = 1.38, 35.08).ConclusionsTreatment and prevention programs should take into account the physical environment, and the concentration of outlets in minority neighborhoods must be addressed as it poses potential health risks to the residents of these neighborhoods.P60 AA009803/AA/NIAAA NIH HHS/United StatesRC1 AA019329-01/AA/NIAAA NIH HHS/United States3P50 AA09803-08S1/AA/NIAAA NIH HHS/United StatesK01 SH000002/SH/NCHS CDC HHS/United States1K01SH000002-01/PHS HHS/United StatesRC1 AA019329/AA/NIAAA NIH HHS/United StatesAA009803-08S1/AA/NIAAA NIH HHS/United StatesP50 AA009803-08S1/AA/NIAAA NIH HHS/United StatesR01 CA157565/CA/NCI NIH HHS/United StatesP50 AA009803/AA/NIAAA NIH HHS/United StatesAA019329-01/RC/CCR NIH HHS/United States2012-05-01T00:00:00Z21323681PMC308345

    "A novel in vivo model for the study of human breast cancer metastasis using primary breast tumor-initiating cells from patient biopsies"

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The study of breast cancer metastasis depends on the use of established breast cancer cell lines that do not accurately represent the heterogeneity and complexity of human breast tumors. A tumor model was developed using primary breast tumor-initiating cells isolated from patient core biopsies that would more accurately reflect human breast cancer metastasis.</p> <p>Methods</p> <p>Tumorspheres were isolated under serum-free culture conditions from core biopsies collected from five patients with clinical diagnosis of invasive ductal carcinoma (IDC). Isolated tumorspheres were transplanted into the mammary fat pad of NUDE mice to establish tumorigenicity <it>in vivo</it>. Tumors and metastatic lesions were analyzed by hematoxylin and eosin (H+E) staining and immunohistochemistry (IHC).</p> <p>Results</p> <p>Tumorspheres were successfully isolated from all patient core biopsies, independent of the estrogen receptor α (ERα)/progesterone receptor (PR)/Her2/neu status or tumor grade. Each tumorsphere was estimated to contain 50-100 cells. Transplantation of 50 tumorspheres (1-5 × 10<sup>3 </sup>cells) in combination with Matrigel into the mammary fat pad of NUDE mice resulted in small, palpable tumors that were sustained up to 12 months post-injection. Tumors were serially transplanted three times by re-isolation of tumorspheres from the tumors and injection into the mammary fat pad of NUDE mice. At 3 months post-injection, micrometastases to the lung, liver, kidneys, brain and femur were detected by measuring content of human chromosome 17. Visible macrometastases were detected in the lung, liver and kidneys by 6 months post-injection. Primary tumors variably expressed cytokeratins, Her2/neu, cytoplasmic E-cadherin, nuclear β catenin and fibronectin but were negative for ERα and vimentin. In lung and liver metastases, variable redistribution of E-cadherin and β catenin to the membrane of tumor cells was observed. ERα was re-expressed in lung metastatic cells in two of five samples.</p> <p>Conclusions</p> <p>Tumorspheres isolated under defined culture conditions from patient core biopsies were tumorigenic when transplanted into the mammary fat pad of NUDE mice, and metastasized to multiple mouse organs. Micrometastases in mouse organs demonstrated a dormancy period prior to outgrowth of macrometastases. The development of macrometastases with organ-specific phenotypic distinctions provides a superior model for the investigation of organ-specific effects on metastatic cancer cell survival and growth.</p

    A Comparative Study of AODV & DSR with Varying Speed, Pause Time, and Node Density over TCP Connections in VANET

    Get PDF
    This paper presents a comparative study of two routing protocols in vehicular ad hoc networks, popularly known as VANETs. A VANET is a special type of ad hoc network consists of moving cars referred to as nodes; provide a way to exchange any information between cars without depending on fixed infrastructure. Due to rapid topology changing and frequent disconnection makes it difficult to select suitable mobility model and routing protocols. Hence performance evaluation and comparison between routing protocols is required to understand any routing protocol as well as to develop a new routing protocol. In this research paper, the performance of two on-demand routing protocols AODV & DSR has been analyzed by means of packet delivery ratio with varying speed limit, pause time, and node density under the TCP connection.. Finally, it concludes the discussion by pointing out some open issues and possible direction of future research related to VANET routing
    • …
    corecore