178 research outputs found

    Transcriptomics reveal an integrative role for maternal thyroid hormones during zebrafish embryogenesis

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    Thyroid hormones (THs) are essential for embryonic brain development but the genetic mechanisms involved in the action of maternal THs (MTHs) are still largely unknown. As the basis for understanding the underlying genetic mechanisms of MTHs regulation we used an established zebrafish monocarboxylic acid transporter 8 (MCT8) knock-down model and characterised the transcriptome in 25hpf zebrafish embryos. Subsequent mapping of differentially expressed genes using Reactome pathway analysis together with in situ expression analysis and immunohistochemistry revealed the genetic networks and cells under MTHs regulation during zebrafish embryogenesis. We found 4,343 differentially expressed genes and the Reactome pathway analysis revealed that TH is involved in 1681 of these pathways. MTHs regulated the expression of core developmental pathways, such as NOTCH and WNT in a cell specific context. The cellular distribution of neural MTH-target genes demonstrated their cell specific action on neural stem cells and differentiated neuron classes. Taken together our data show that MTHs have a role in zebrafish neurogenesis and suggest they may be involved in cross talk between key pathways in neural development. Given that the observed MCT8 zebrafish knockdown phenotype resembles the symptoms in human patients with Allan-Herndon-Dudley syndrome our data open a window into understanding the genetics of this human congenital condition.Portuguese Fundacao para Ciencia e Tecnologia (FCT) [PTDC/EXPL/MARBIO/0430/2013]; CCMAR FCT Plurianual financing [UID/Multi/04326/2013]; FCT [SFRH/BD/111226/2015, SFRH/BD/108842/2015, SFRH/BPD/89889/2012]; FCT-IF Starting Grant [IF/01274/2014]info:eu-repo/semantics/publishedVersio

    Coordinated generation of multiple ocular-like cell lineages and fabrication of functional corneal epithelial cell sheets from human iPS cells

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    We describe a protocol for the generation of a functional and transplantable corneal epithelium derived from human induced pluripotent stem (iPS) cells. When this protocol is followed, a proportion of iPS cells spontaneously form circular colonies, each of which is composed of four concentric zones. Cells in these zones have different morphologies and immunostaining characteristics, resembling neuroectoderm, neural crest, ocular-surface ectoderm, or surface ectoderm. We have named this 2D colony a 'SEAM' (self-formed ectodermal autonomous multizone), and previously demonstrated that cells within the SEAM have the potential to give rise to anlages of different ocular lineages, including retinal cells, lens cells, and ocular-surface ectoderm. To investigate the translational potential of the SEAM, cells within it that resemble ocular-surface epithelia can be isolated by pipetting and FACS sorting into a population of corneal epithelial-like progenitor cells. These can be expanded and differentiated to form an epithelial layer expressing K12 and PAX6, and able to recover function in an animal model of corneal epithelial dysfunction after surgical transplantation. The whole protocol, encompassing human iPS cell preparation, autonomous differentiation, purification, and subsequent differentiation, takes between 100 and 120 d, and is of potential use to researchers with an interest in eye development and/or ocular-surface regeneration. Experience with human iPS cell culture and sorting via FACS will be of benefit for researchers performing this protocol

    Hydrocarbon Contamination Decreases Mating Success in a Marine Planktonic Copepod

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    The mating behavior and the mating success of copepods rely on chemoreception to locate and track a sexual partner. However, the potential impact of the water-soluble fraction of hydrocarbons on these aspects of copepod reproduction has never been tested despite the widely acknowledged acute chemosensory abilities of copepods. I examined whether three concentrations of the water-soluble fraction of diesel oil (0.01%, 0.1% and 1%) impacts (i) the swimming behavior of both adult males and females of the widespread calanoid copepod Temora longcornis, and (ii) the ability of males to locate, track and mate with females. The three concentrations of the water-soluble fraction of diesel oil (WSF) significantly and non-significantly affect female and male swimming velocities, respectively. In contrast, both the complexity of male and female swimming paths significantly decreased with increasing WSF concentrations, hence suggesting a sex-specific sensitivity to WSF contaminated seawater. In addition, the three WSF concentrations impacted both T. longicornis mating behavior and mating success. Specifically, the ability of males to detect female pheromone trails, to accurately follow trails and to successfully track a female significantly decreased with increasing WSF concentrations. This led to a significant decrease in contact and capture rates from control to WSF contaminated seawater. These results indicate that hydrocarbon contamination of seawater decreases the ability of male copepods to detect and track a female, hence suggest an overall impact on population fitness and dynamics

    Social validity of randomised controlled trials in health services research and intellectual disabilities: a qualitative exploration of stakeholder views

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    <p>Abstract</p> <p>Background</p> <p>Randomised controlled trials (RCTs) are the gold standard of evidence-based practice in medicine but they have had limited influence in the field of intellectual disabilities. Previous literature suggests that participants and professionals have limited tolerance for this type of research methodology. However, it is not known how well service users, carers and other health professionals understand and accept the need for RCTs, and why it is important for individuals with intellectual disabilities to be included in this kind of research.</p> <p>Methods</p> <p>We examined individual perceptions of RCTs in 51 participants (18 carers, 6 service users and 27 professionals) using semi-structured interviews. A framework approach was adopted in the analysis of data.</p> <p>Results</p> <p>We found that participants had concerns about capacity and resource allocation but held positive views towards this type of research methodology. Understanding of the principles behind RCTs was poor amongst service users and a minority of carers, but mediated by previous exposure to research for professionals.</p> <p>Conclusions</p> <p>The social validity of RCTs in intellectual disabilities may be compromised by lack of understanding of the design and the on-going concerns about obtaining informed consent especially in incapacitated adults. However, the overall finding that the need for this form of research was seen in a positive light suggests that there is a turning point in the perceptions of stakeholders working in intellectual disabilities services. We recommend that researchers include on-going education on RCT design during trials, tailoring it to all stakeholders with emphasis on strong service user and care involvement. This could be a pivotal element in improving acceptability of, and recruitment to RCTs.</p

    Identification of a Circadian Clock-Controlled Neural Pathway in the Rabbit Retina

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    Background: Although the circadian clock in the mammalian retina regulates many physiological processes in the retina, it is not known whether and how the clock controls the neuronal pathways involved in visual processing. Methodology/Principal Findings: By recording the light responses of rabbit axonless (A-type) horizontal cells under darkadapted conditions in both the day and night, we found that rod input to these cells was substantially increased at night under control conditions and following selective blockade of dopamine D2, but not D1, receptors during the day, so that the horizontal cells responded to very dim light at night but not in the day. Using neurobiotin tracer labeling, we also found that the extent of tracer coupling between rabbit rods and cones was more extensive during the night, compared to the day, and more extensive in the day following D 2 receptor blockade. Because A-type horizontal cells make synaptic contact exclusively with cones, these observations indicate that the circadian clock in the mammalian retina substantially increases rod input to A-type horizontal cells at night by enhancing rod-cone coupling. Moreover, the clock-induced increase in D2 receptor activation during the day decreases rod-cone coupling so that rod input to A-type horizontal cells is minimal. Conclusions/Significance: Considered together, these results identify the rod-cone gap junction as a key site in mammals through which the retinal clock, using dopamine activation of D2 receptors, controls signal flow in the day and night fro

    The quantified self: what counts in the neoliberal workplace

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    Implementation of quantified self technologies in workplaces relies on the ontological premise of Cartesian dualism with mind dominant over body. Contributing to debates in new materialism, we demonstrate that workers are now being asked to measure our own productivity and health and wellbeing in art-houses and warehouses alike in both the global north and south. Workers experience intensified precarity, austerity, intense competition for jobs, and anxieties about the replacement of labour-power with robots and other machines as well as, ourselves replaceable, other humans. Workers have internalized the imperative to perform, a subjectification process as we become observing, entrepreneurial subjects and observed, objectified labouring bodies. Thinking through the implications of the use of wearable technologies in workplaces, this article shows that these technologies introduce a heightened Taylorist influence on precarious working bodies within neoliberal workplaces

    Phase II trial of radiotherapy after hyperbaric oxygenation with chemotherapy for high-grade gliomas

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    We conducted a phase II trial to evaluate the efficacy and toxicity of radiotherapy immediately after hyperbaric oxygenation (HBO) with chemotherapy in adults with high-grade gliomas. Patients with histologically confirmed high-grade gliomas were administered radiotherapy in daily 2 Gy fractions for 5 consecutive days per week up to a total dose of 60 Gy. Each fraction was administered immediately after HBO with the period of time from completion of decompression to irradiation being less than 15 min. Chemotherapy consisted of procarbazine, nimustine (ACNU) and vincristine and was administered during and after radiotherapy. A total of 41 patients (31 patients with glioblastoma and 10 patients with grade 3 gliomas) were enrolled. All 41 patients were able to complete a total radiotherapy dose of 60 Gy immediately after HBO with one course of concurrent chemotherapy. Of 30 assessable patients, 17 (57%) had an objective response including four CR and 13 PR. The median time to progression and the median survival time in glioblastoma patients were 12.3 months and 17.3 months, respectively. On univariate analysis, histologic grade (P=0.0001) and Karnofsky performance status (P=0.036) had a significant impact on survival, and on multivariate analysis, histologic grade alone was a significant prognostic factor for survival (P=0.001). Although grade 4 leukopenia and grade 4 thrombocytopenia occurred in 10 and 7% of all patients, respectively, these were transient with no patients developing neutropenic fever or intracranial haemorrhage. No serious nonhaematological or late toxicities were seen. These results indicated that radiotherapy delivered immediately after HBO with chemotherapy was safe with virtually no late toxicity in patients with high-grade gliomas. Further studies are required to strictly evaluate the effectiveness of radiotherapy after HBO for these tumours

    Ectopic synaptic ribbons in dendrites of mouse retinal ON- and OFF-bipolar cells

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    The ectopic distribution of synaptic ribbons in dendrites of mouse retinal bipolar cells was examined by using genetic ablation of metabotropic glutamate receptor subtype 6 (mGluR6), electron microscopy, and immunocytochemistry. Ectopic ribbons were observed in dendrites of rod and ON-cone bipolar cells in the mGluR6-deficient mouse but not in those of wild-type mice. The number of rod spherules facing the ectopic ribbons in mGluR6-deficient rod bipolar dendrites increased gradually during early growth and reached a plateau level of about 20% at 12 weeks. These ectopic ribbons were immunopositive for RIBEYE, a ribbon-specific protein, but the associated vesicles were immunonegative for synaptophysin, a synaptic-vesicle-specific protein. The presence of ectopic ribbons was correlated with an increase in the roundness of the invaginating dendrites of the rod bipolar cells. We further confirmed ectopic ribbons in dendrites of OFF-cone bipolar cells in wild-type retinas. Of the four types of OFF-cone bipolar cells (T1–T4), only the T2-type, which had a greater number of synaptic ribbons at the axon terminal and a thicker axon cylinder than the other types, had ectopic ribbons. Light-adapted experiments revealed that, in wild-type mice under enhanced-light adaptation (considered similar to the mGluR6-deficient state), the roundness in the invaginating dendrites and axon terminals of rod bipolar cells increased, but no ectopic ribbons were detected. Based on these findings and known mechanisms for neurotransmitter release and protein trafficking, the possible mechanisms underlying the ectopic ribbons are discussed on the basis of intracellular transport for the replenishment of synaptic proteins

    High-Throughput High-Resolution Class I HLA Genotyping in East Africa

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    HLA, the most genetically diverse loci in the human genome, play a crucial role in host-pathogen interaction by mediating innate and adaptive cellular immune responses. A vast number of infectious diseases affect East Africa, including HIV/AIDS, malaria, and tuberculosis, but the HLA genetic diversity in this region remains incompletely described. This is a major obstacle for the design and evaluation of preventive vaccines. Available HLA typing techniques, that provide the 4-digit level resolution needed to interpret immune responses, lack sufficient throughput for large immunoepidemiological studies. Here we present a novel HLA typing assay bridging the gap between high resolution and high throughput. The assay is based on real-time PCR using sequence-specific primers (SSP) and can genotype carriers of the 49 most common East African class I HLA-A, -B, and -C alleles, at the 4-digit level. Using a validation panel of 175 samples from Kampala, Uganda, previously defined by sequence-based typing, the new assay performed with 100% sensitivity and specificity. The assay was also implemented to define the HLA genetic complexity of a previously uncharacterized Tanzanian population, demonstrating its inclusion in the major East African genetic cluster. The availability of genotyping tools with this capacity will be extremely useful in the identification of correlates of immune protection and the evaluation of candidate vaccine efficacy
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