895 research outputs found

    An alternative approach to contrast-enhanced imaging: diffusion-weighted imaging and T1-weighted imaging identifies and quantifies necrosis in Wilms tumour

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    OBJECTIVES: Volume of necrosis in Wilms tumour is informative of chemotherapy response. Contrast-enhanced T1-weighted MRI (T1w) provides a measure of necrosis using gadolinium. This study aimed to develop a non-invasive method of identifying non-enhancing (necrotic) tissue in Wilms tumour. METHODS: In this single centre, retrospective study, post-chemotherapy MRI data from 34 Wilms tumour patients were reviewed (March 2012-March 2017). Cases with multiple b value diffusion-weighted imaging (DWI) and T1w imaging pre- and post-gadolinium were included. Fractional T1 enhancement maps were generated from the gadolinium T1w data. Multiple linear regression determined whether fitted parameters from a mono-exponential model (ADC) and bi-exponential model (IVIM - intravoxel incoherent motion) (D, D*, f) could predict fractional T1 enhancement in Wilms tumours, using normalised pre-gadolinium T1w (T1wnorm) signal as an additional predictor. Measured and predicted fractional enhancement values were compared using the Bland-Altman plot. An optimum threshold for separating necrotic and viable tissue using fractional T1 enhancement was established using ROC. RESULTS: ADC and D (diffusion coefficient) provided the strongest predictors of fractional T1 enhancement in tumour tissue (p < 0.001). Using the ADC-T1wnorm model (adjusted R2 = 0.4), little bias (mean difference = - 0.093, 95% confidence interval = [- 0.52, 0.34]) was shown between predicted and measured values of fractional enhancement and analysed via the Bland-Altman plot. The optimal threshold for differentiating viable and necrotic tissue was 33% fractional T1 enhancement (based on measured values, AUC = 0.93; sensitivity = 85%; specificity = 90%). CONCLUSIONS: Combining ADC and T1w imaging predicts enhancement in Wilms tumours and reliably identifies and measures necrotic tissue without gadolinium. KEY POINTS: • Alternative method to identify necrotic tissue in Wilms tumour without using contrast agents but rather using diffusion and T 1 weighted MRI. • A method is presented to visualise and quantify necrotic tissue in Wilms tumour without contrast. • The proposed method has the potential to reduce costs and burden to Wilms tumour patients who undergo longitudinal follow-up imaging as contrast agents are not used

    Relationship of literacy and heart failure in adults with diabetes

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    <p>Abstract</p> <p>Background</p> <p>Although reading ability may impact educational strategies and management of heart failure (HF), the prevalence of limited literacy in patients with HF is unknown.</p> <p>Methods</p> <p>Subjects were drawn from the Vermont Diabetes Information System Field Survey, a cross-sectional study of adults with diabetes in primary care. Participants' self-reported characteristics were subjected to logistic regression to estimate the association of heart failure and literacy while controlling for social and economic factors. The Short Test of Functional Health Literacy was used to measure literacy.</p> <p>Results</p> <p>Of 172 subjects with HF and diabetes, 27% had limited literacy compared to 15% of 826 subjects without HF (OR 2.05; 95% CI 1.39, 3.02; <it>P </it>< 0.001). Adjusting for age, sex, race, income, marital status and health insurance, HF continued to be significantly associated with limited literacy (OR 1.55, 95% CI 1.00, 2.41, <it>P </it>= .05).</p> <p>After adjusting for education, however, HF was no longer independently associated with literacy (OR 1.31; 95% CI 0.82 – 2.08; <it>P </it>= 0.26).</p> <p>Conclusion</p> <p>Over one quarter of diabetic adults with HF have limited literacy. Although this association is no longer statistically significant when adjusted for education, clinicians should be aware that many of their patients have important limitations in dealing with written materials.</p

    Quantitative model for inferring dynamic regulation of the tumour suppressor gene p53

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    Background: The availability of various "omics" datasets creates a prospect of performing the study of genome-wide genetic regulatory networks. However, one of the major challenges of using mathematical models to infer genetic regulation from microarray datasets is the lack of information for protein concentrations and activities. Most of the previous researches were based on an assumption that the mRNA levels of a gene are consistent with its protein activities, though it is not always the case. Therefore, a more sophisticated modelling framework together with the corresponding inference methods is needed to accurately estimate genetic regulation from "omics" datasets. Results: This work developed a novel approach, which is based on a nonlinear mathematical model, to infer genetic regulation from microarray gene expression data. By using the p53 network as a test system, we used the nonlinear model to estimate the activities of transcription factor (TF) p53 from the expression levels of its target genes, and to identify the activation/inhibition status of p53 to its target genes. The predicted top 317 putative p53 target genes were supported by DNA sequence analysis. A comparison between our prediction and the other published predictions of p53 targets suggests that most of putative p53 targets may share a common depleted or enriched sequence signal on their upstream non-coding region. Conclusions: The proposed quantitative model can not only be used to infer the regulatory relationship between TF and its down-stream genes, but also be applied to estimate the protein activities of TF from the expression levels of its target genes

    Do adults with high functioning autism or Asperger Syndrome differ in empathy and emotion recognition?

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    The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (i) their self-reported ability to empathise with others and/or (ii) their ability to read mental states in others’ eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes’ Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions

    A direct physical interaction between Nanog and Sox2 regulates embryonic stem cell self-renewal

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    Embryonic stem (ES) cell self-renewal efficiency is determined by the Nanog protein level. However, the protein partners of Nanog that function to direct self-renewal are unclear. Here, we identify a Nanog interactome of over 130 proteins including transcription factors, chromatin modifying complexes, phosphorylation and ubiquitination enzymes, basal transcriptional machinery members, and RNA processing factors. Sox2 was identified as a robust interacting partner of Nanog. The purified Nanog–Sox2 complex identified a DNA recognition sequence present in multiple overlapping Nanog/Sox2 ChIP-Seq data sets. The Nanog tryptophan repeat region is necessary and sufficient for interaction with Sox2, with tryptophan residues required. In Sox2, tyrosine to alanine mutations within a triple-repeat motif (S X T/S Y) abrogates the Nanog–Sox2 interaction, alters expression of genes associated with the Nanog-Sox2 cognate sequence, and reduces the ability of Sox2 to rescue ES cell differentiation induced by endogenous Sox2 deletion. Substitution of the tyrosines with phenylalanine rescues both the Sox2–Nanog interaction and efficient self-renewal. These results suggest that aromatic stacking of Nanog tryptophans and Sox2 tyrosines mediates an interaction central to ES cell self-renewal

    CAR-T cell. the long and winding road to solid tumors

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    Adoptive cell therapy of solid tumors with reprogrammed T cells can be considered the "next generation" of cancer hallmarks. CAR-T cells fail to be as effective as in liquid tumors for the inability to reach and survive in the microenvironment surrounding the neoplastic foci. The intricate net of cross-interactions occurring between tumor components, stromal and immune cells leads to an ineffective anergic status favoring the evasion from the host's defenses. Our goal is hereby to trace the road imposed by solid tumors to CAR-T cells, highlighting pitfalls and strategies to be developed and refined to possibly overcome these hurdles

    A Pilot Study of Lay Health Worker Outreach and Colorectal Cancer Screening Among Chinese Americans

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    The research team recruited eight Chinese American (seven females, one male) lay health workers (LHWs). They received 12 h of training about colorectal cancer (CRC), its screening, and basic health education techniques. Each LHW were asked to recruit ten participants and conduct two educational sessions. Of the 81 participants recruited, 73 had not received colorectal cancer screening. Their mean age was 63.0 years, and 72.6% were women. Knowledge of colorectal cancer, its causes, and its screening increased significantly. Receipt of first colorectal cancer screening test increased from 0.0% at baseline to 55.7% for fecal occult blood tests, 7.1% for sigmoidoscopy, and 7.1% for colonoscopy. LHW outreach is feasible and may be effective in promoting CRC screening among Chinese Americans

    Autism as a disorder of neural information processing: directions for research and targets for therapy

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    The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

    Oxytocin and Vasopressin Involved in Restraint Water-Immersion Stress Mediated by Oxytocin Receptor and Vasopressin 1b Receptor in Rat Brain

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    Aims: Vasopressin (AVP) and oxytocin (OT) are considered to be related to gastric functions and the regulation of stress response. The present study was to study the role of vasopressinergic and oxytocinergic neurons during the restraint waterimmersion stress. Methods: Ten male Wistar rats were divided into two groups, control and RWIS for 1h. The brain sections were treated with a dual immunohistochemistry of Fos and oxytocin (OT) or vasopressin (AVP) or OT receptor or AVP 1b receptor (V1bR). Results: (1) Fos-immunoreactive (Fos-IR) neurons dramatically increased in the hypothalamic paraventricular nucleus (PVN), the supraoptic nucleus (SON), the neucleus of solitary tract (NTS) and motor nucleus of the vagus (DMV) in the RWIS rats; (2) OT-immunoreactive (OT-IR) neurons were mainly observed in the medial magnocellular part of the PVN and the dorsal portion of the SON, while AVP-immunoreactive (AVP-IR) neurons mainly distributed in the magnocellular part of the PVN and the ventral portion of the SON. In the RWIS rats, Fos-IR neurons were indentified in 31 % of OT-IR neurons and 40 % of AVP-IR neurons in the PVN, while in the SON it represented 28%, 53 % respectively; (3) V 1bR-IR and OTR-IR neurons occupied all portions of the NTS and DMV. In the RWIS rats, more than 10 % of OTR-IR and V1bR-IR neurons were activated in the DMV, while lower ratio in the NTS. Conclusion: RWIS activates both oxytocinergic and vasopressinergic neurons in the PVN and SON, which may project to th
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