481 research outputs found

    Oxytocin Receptor Polymorphism Decreases Midline Neural Activations to Social Stimuli in Anorexia Nervosa

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    Oxytocin is a neurotransmitter related to both feeding and social behavior; anorexia nervosa is a psychiatric illness defined by reduced food intake, weight loss, and problems in social perceptions. Oxytocin receptor single nucleotide polymorphisms rs2254298 or rs53576 and neural responses to social stimuli were evaluated in adult women with or recovered from anorexia nervosa using functional magnetic resonance imaging. Carriers of the A allele for OXTR rs2254298 (2 AA and 10 AG) showed significantly reduced activation of portions of the posterior cingulate cortex and medial prefrontal cortex for social stimuli as well as greater negative connectivity between the posterior cingulate and the occipital lobe relative to the GG subjects for rs2254298. Differences in the other OXTR SNP, rs53576, did not result in detectable neural differences in either whole brain or region of interest analyses. Development of a mechanistic, biological model of how social behavior is impacted by mental illness requires linking genes to functional brain activations in disease. This pilot study suggests that in anorexia nervosa, differences related to OXTR SNP rs2254298 may alter neural responses to social stimuli and disrupt the engagement and disengagement of the default mode network

    Deficits in Analogical Reasoning in Adolescents with Traumatic Brain Injury

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    Individuals with traumatic brain injury (TBI) exhibit deficits in executive control, which may impact their reasoning abilities. Analogical reasoning requires working memory and inhibitory abilities. In this study, we tested adolescents with moderate to severe TBI and typically developing (TD) controls on a set of picture analogy problems. Three factors were varied: complexity (number of relations in the problems), distraction (distractor item present or absent), and animacy (living or non-living items in the problems). We found that TD adolescents performed significantly better overall than TBI adolescents. There was also an age effect present in the TBI group where older participants performed better than younger ones. This age effect was not observed in the TD group. Performance was affected by complexity and distraction. Further, TBI participants exhibited lower performance with distractors present than TD participants. The reasoning deficits exhibited by the TBI participants were correlated with measures of executive function that required working memory updating, attention, and attentional screening. Using MRI-derived measures of cortical thickness, correlations were carried out between task accuracy and cortical thickness. The TD adolescents showed negative correlations between thickness and task accuracy in frontal and temporal regions consistent with cortical maturation in these regions. This study demonstrates that adolescent TBI results in impairments in analogical reasoning ability. Further, TBI youth have difficulty effectively screening out distraction, which may lead to failures in comprehension of the relations among items in visual scenes. Lastly, TBI youth fail to show robust cortical–behavior correlations as observed in TD individuals

    CIV Emission and the Ultraviolet through X-ray Spectral Energy Distribution of Radio-Quiet Quasars

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    In the restframe UV, two of the parameters that best characterize the range of emission-line properties in quasar broad emission-line regions are the equivalent width and the blueshift of the CIV line relative to the quasar rest frame. We explore the connection between these emission-line properties and the UV through X-ray spectral energy distribution (SED) for radio-quiet (RQ) quasars. Our sample consists of a heterogeneous compilation of 406 quasars from the Sloan Digital Sky Survey and Palomar-Green survey that have well-measured CIV emission-line and X-ray properties (including 164 objects with measured Gamma). We find that RQ quasars with both strong CIV emission and small CIV blueshifts can be classified as "hard-spectrum" sources that are (relatively) strong in the X-ray as compared to the UV. On the other hand, RQ quasars with both weak CIV emission and large CIV blueshifts are instead "soft-spectrum" sources that are (relatively) weak in the X-ray as compared to the UV. This work helps to further bridge optical/soft X-ray "Eigenvector 1" relationships to the UV and hard X-ray. Based on these findings, we argue that future work should consider systematic errors in bolometric corrections (and thus accretion rates) that are derived from a single mean SED. Detailed analysis of the CIV emission line may allow for SED-dependent corrections to these quantities.Comment: AJ, in press; 39 pages, 11 figures, 3 table

    A Key Role for Neurotensin in Chronic-Stress-Induced Anxiety-Like Behavior in Rats

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    Accepted ManuscriptChronic stress is a major cause of anxiety disorders that can be reliably modeled preclinically, providing insight into alternative therapeutic targets for this mental health illness. Neuropeptides have been targeted in the past to no avail possibly due to our lack of understanding of their role in pathological models. In this study we use a rat model of chronic stress-induced anxiety-like behaviors and hypothesized that neuropeptidergic modulation of synaptic transmission would be altered in the bed nucleus of the stria terminalis (BNST), a brain region suspected to contribute to anxiety disorders. We use brain slice neurophysiology and behavioral pharmacology to compare the role of locally released endogenous neuropeptides on synaptic transmission in the oval (ov) BNST of non-stressed (NS) or chronic unpredictably stressed (CUS) rats. We found that in NS rats, post-synaptic depolarization induced the release of vesicular neurotensin (NT) and corticotropin-releasing factor (CRF) that co-acted to increase ovBNST inhibitory synaptic transmission in 59% of recorded neurons. CUS bolstered this potentiation (100% of recorded neurons) through an enhanced contribution of NT over CRF. In contrast, locally released opioid neuropeptides decreased ovBNST excitatory synaptic transmission in all recorded neurons, regardless of stress. Consistent with CUS-induced enhanced modulatory effects of NT, blockade of ovBNST NT receptors completely abolished stress-induced anxiety-like behaviors in the elevated plus maze paradigm. The role of NT has been largely unexplored in stress and our findings highlight its potential contribution to an important behavioral consequence of chronic stress, that is, exaggerated avoidance of open space in rats.CPN was funded by CIHR Vanier Graduate Scholarship (338319); APVS was funded by Fundação para a Ciência e Tecnologia (SFRH/BPD/52078/2013); ERH was funded by CIHR Postdoctoral Fellowship (MFE-123712); SA was funded by a Queen Elizabeth II Graduate Scholarship in Science and Technology; ÉCD was funded by the Canadian Institute of Health Research (MOP-25953)info:eu-repo/semantics/publishedVersio

    Metallated phthalocyanines and their hydrophilic derivatives for multi-targeted oncological photodynamic therapy

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    Background and aim: A photosensitizer (PS) delivery and comprehensive tumor targeting platform was developed that is centered on the photosensitization of key pharmacological targets in solid tumors (cancer cells, tumor vascular endothelium, and cellular and non-cellular components of the tumor microenvironment) before photodynamic therapy (PDT). Interstitially targeted liposomes (ITLs) encapsulating zinc phthalocyanine (ZnPC) and aluminum phthalocyanine (AlPC) were formulated for passive targeting of the tumor microenvironment. In previous work it was established that the PEGylated ITLs were taken up by cultured cholangiocarcinoma cells. The aim of this study was to verify previous results in cancer cells and to determine whether the ITLs can also be used to photosensitize cells in the tumor microenvironment and vasculature. Following positive results, rudimentary in vitro and in vivo experiments were performed with ZnPC-ITLs and AlPC-ITLs as well as their water-soluble tetrasulfonated derivatives (ZnPCS4 and AlPCS4) to assemble a research dossier and bring this platform closer to clinical transition. Methods: Flow cytometry and confocal microscopy were employed to determine ITL uptake and PS distribution in cholangiocarcinoma (SK-ChA-1) cells, endothelial cells (HUVECs), fibroblasts (NIH-3T3), and macrophages (RAW 264.7). Uptake of ITLs by endothelial cells was verified under flow conditions in a flow chamber. Dark toxicity and PDT efficacy were determined by cell viability assays, while the mode of cell death and cell cycle arrest were assayed by flow cytometry. In vivo systemic toxicity was assessed in zebrafish and chicken embryos, whereas skin phototoxicity was determined in BALB/c nude mice. A PDT efficacy pilot was conducted in BALB/c nude mice bearing human triple-negative breast cancer (MDA-MB-231) xenografts. Results: The key findings were that (1) photodynamically active PSs (i.e., all except ZnPCS4) were able to effectively photosensitize cancer cells and non-cancerous cells; (2) following PDT, photodynamically active PSs were highly toxic-to-potent as per anti-cancer compound classification; (3) the photodynamically active PSs did not elicit notable systemic toxicity in zebrafish and chicken embryos; (4) ITL-delivered ZnPC and ZnPCS4 were associated with skin phototoxicity, while the aluminum-containing PSs did not exert detectable skin phototoxicity; and (5) ITL-delivered ZnPC and AlPC were equally effective in their tumor-killing capacity in human tumor breast cancer xenografts and superior to other non-phthalocyanine PSs when appraised on a per mole administered dose basis. Conclusions: AlPC(S4) are the safest and most effective PSs to integrate into the comprehensive tumor targeting and PS delivery platform. Pending further in vivo validation, these third-generation PSs may be used for multi-compartmental tumor photosensitization

    Galaxy Zoo: quantitative visual morphological classifications for 48 000 galaxies from CANDELS

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    We present quantified visual morphologies of approximately 48 000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90 per cent of galaxies have z ≤ 3 and are observed in rest-frame optical wavelengths by CANDELS. Each galaxy received an average of 40 independent classifications, which we combine into detailed morphological information on galaxy features such as clumpiness, bar instabilities, spiral structure, and merger and tidal signatures. We apply a consensus-based classifier weighting method that preserves classifier independence while effectively down-weighting significantly outlying classifications. After analysing the effect of varying image depth on reported classifications, we also provide depth-corrected classifications which both preserve the information in the deepest observations and also enable the use of classifications at comparable depths across the full survey. Comparing the Galaxy Zoo classifications to previous classifications of the same galaxies shows very good agreement; for some applications, the high number of independent classifications provided by Galaxy Zoo provides an advantage in selecting galaxies with a particular morphological profile, while in others the combination of Galaxy Zoo with other classifications is a more promising approach than using any one method alone. We combine the Galaxy Zoo classifications of ‘smooth’ galaxies with parametric morphologies to select a sample of featureless discs at 1 ≤ z ≤ 3, which may represent a dynamically warmer progenitor population to the settled disc galaxies seen at later epochs

    Liver Phenotypes of European Adults Heterozygous or Homozygous for Pi∗Z Variant of AAT (Pi∗MZ vs Pi∗ZZ genotype) and Noncarriers

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    Homozygosity for the Pi∗Z variant of the gene that encodes the alpha-1 antitrypsin peptide (AAT), called the Pi∗ZZ genotype, causes a liver and lung disease called alpha-1 antitrypsin deficiency. Heterozygosity (the Pi∗MZ genotype) is a risk factor for cirrhosis in individuals with liver disease. Up to 4% of Europeans have the Pi∗MZ genotype; we compared features of adults with and without Pi∗MZ genotype among persons without preexisting liver disease.info:eu-repo/semantics/publishedVersio

    A Genome-Wide Association Study of Total Bilirubin and Cholelithiasis Risk in Sickle Cell Anemia

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    Serum bilirubin levels have been associated with polymorphisms in the UGT1A1 promoter in normal populations and in patients with hemolytic anemias, including sickle cell anemia. When hemolysis occurs circulating heme increases, leading to elevated bilirubin levels and an increased incidence of cholelithiasis. We performed the first genome-wide association study (GWAS) of bilirubin levels and cholelithiasis risk in a discovery cohort of 1,117 sickle cell anemia patients. We found 15 single nucleotide polymorphisms (SNPs) associated with total bilirubin levels at the genome-wide significance level (p value <5×10−8). SNPs in UGT1A1, UGT1A3, UGT1A6, UGT1A8 and UGT1A10, different isoforms within the UGT1A locus, were identified (most significant rs887829, p = 9.08×10−25). All of these associations were validated in 4 independent sets of sickle cell anemia patients. We tested the association of the 15 SNPs with cholelithiasis in the discovery cohort and found a significant association (most significant p value 1.15×10−4). These results confirm that the UGT1A region is the major regulator of bilirubin metabolism in African Americans with sickle cell anemia, similar to what is observed in other ethnicities

    Metallated phthalocyanines and their hydrophilic derivatives for multi-targeted oncological photodynamic therapy

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    Background and aim: A photosensitizer (PS) delivery and comprehensive tumor targeting platform was developed that is centered on the photosensitization of key pharmacological targets in solid tumors (cancer cells, tumor vascular endothelium, and cellular and non-cellular components of the tumor microenvironment) before photodynamic therapy (PDT). Interstitially targeted liposomes (ITLs) encapsulating zinc phthalocyanine (ZnPC) and aluminum phthalocyanine (AlPC) were formulated for passive targeting of the tumor microenvironment. In previous work it was established that the PEGylated ITLs were taken up by cultured cholangiocarcinoma cells. The aim of this study was to verify previous results in cancer cells and to determine whether the ITLs can also be used to photosensitize cells in the tumor microenvironment and vasculature. Following positive results, rudimentary in vitro and in vivo experiments were performed with ZnPC-ITLs and AlPC-ITLs as well as their water-soluble tetrasulfonated derivatives (ZnPCS4 and AlPCS4) to assemble a research dossier and bring this platform closer to clinical transition. Methods: Flow cytometry and confocal microscopy were employed to determine ITL uptake and PS distribution in cholangiocarcinoma (SK-ChA-1) cells, endothelial cells (HUVECs), fibroblasts (NIH-3T3), and macrophages (RAW 264.7). Uptake of ITLs by endothelial cells was verified under flow conditions in a flow chamber. Dark toxicity and PDT efficacy were determined by cell viability assays, while the mode of cell death and cell cycle arrest were assayed by flow cytometry. In vivo systemic toxicity was assessed in zebrafish and chicken embryos, whereas skin phototoxicity was determined in BALB/c nude mice. A PDT efficacy pilot was conducted in BALB/c nude mice bearing human triple-negative breast cancer (MDA-MB-231) xenografts. Results: The key findings were that (1) photodynamically active PSs (i.e., all except ZnPCS4) were able to effectively photosensitize cancer cells and non-cancerous cells; (2) following PDT, photodynamically active PSs were highly toxic-to-potent as per anti-cancer compound classification; (3) the photodynamically active PSs did not elicit notable systemic toxicity in zebrafish and chicken embryos; (4) ITL-delivered ZnPC and ZnPCS4 were associated with skin phototoxicity, while the aluminum-containing PSs did not exert detectable skin phototoxicity; and (5) ITL-delivered ZnPC and AlPC were equally effective in their tumor-killing capacity in human tumor breast cancer xenografts and superior to other non-phthalocyanine PSs when appraised on a per mole administered dose basis. Conclusions: AlPC(S4) are the safest and most effective PSs to integrate into the comprehensive tumor targeting and PS delivery platform. Pending further in vivo validation, these third-generation PSs may be used for multi-compartmental tumor photosensitization
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