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Found 37769 matches. Displaying 3521-3530
Haralson Z, Goree J, Belousov R
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Dusty plasma experiment to confirm an expression for the decay of autocorrelation functions

PHYSICAL REVIEW E 2018 AUG 8; 98(2):? Article 023201
Statistical physicists recently proposed an expression for an autocorrelation function (ACF) [Belousov and Cohen, Phys. Rev. E 94, 062124 (2016)] that has, until now, not been tested experimentally. The expression captures the early behavior of the ACF decay, when the ACF is flattened. Using experimental data from a nonequilibnum steady-state dusty plasma, we confirm that the expression's use extends to liquidlike strongly coupled plasmas. A transition in the shape of the ACF is identified, and we suggest that it corresponds to the onset of collisional scattering.
del Marmol JI, Touhara KK, Croft G, MacKinnon R
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Piezo1 forms a slowly-inactivating mechanosensory channel in mouse embryonic stem cells

ELIFE 2018 AUG 22; 7(?):? Article e33149
Piezo1 is a mechanosensitive (MS) ion channel with characteristic fast-inactivation kinetics. We found a slowly-inactivating MS current in mouse embryonic stem (mES) cells and characterized it throughout their differentiation into motor-neurons to investigate its components. MS currents were large and slowly-inactivating in the stem-cell stage, and became smaller and faster-inactivating throughout the differentiation. We found that Piezo1 is expressed in mES cells, and its knockout abolishes MS currents, indicating that the slowly-inactivating current in mES cells is carried by Piezo1. To further investigate its slow inactivation in these cells, we cloned Piezo1 cDNA from mES cells and found that it displays fast-inactivation kinetics in heterologous expression, indicating that sources of modulation other than the aminoacid sequence determine its slow kinetics in mES cells. Finally, we report that Piezo1 knockout ES cells showed a reduced rate of proliferation but no significant differences in other markers of pluripotency and differentiation.
Huang XJ, Meyers K, Liu XC, Li X, Zhang T, Xia W, Hou JH, Song AX, He HL, Li CX, He SH, Cai WP, Zhong HL, Huang CY, Liu SQ, Wang H, Ling XM, Ma P, Ye RX, Xiao G, Li TS, Ding D, Yaffe K, Chen H, Chen Y, Wu H
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The Double Burdens of Mental Health Among AIDS Patients With Fully Successful Immune Restoration: A Cross-Sectional Study of Anxiety and Depression in China

FRONTIERS IN PSYCHIATRY 2018 AUG 24; 9(?):? Article 384
Background: Anxiety and depression continue to be significant comorbidities for people with HIV infection. We investigated the prevalence of and factors associated with anxiety and depression among adult HIV-infected patients across China. Methods: In this cross-sectional study, we described clinical and psychosocial variables related to depression and anxiety in 4103 HIV-infected persons. Doctors assessed anxiety and depression by asking patients whether they had experienced anxiety or depression in the prior month. Patients also self-administered the Hospital Anxiety and Depression (HAD) scale; those with score >= 8 on HAD-A/D were considered to be at high risk of anxiety or depression. Results: Associations between socio-demographic, psychosocial, and ART-related clinical factors and risk of depression or anxiety were investigated using multivariable logistic regression. Among patients assessed between 9/2014 and 11/2015, 27.4% had symptoms of anxiety, 32.9% had symptoms of depression, and 19.0% had both. Recentness of HIV diagnoses (P = 0.046) was associated with elevated odds of anxiety. Older age (P = 0.004), higher educational attainment (P < 0.001), employment (P = 0.001), support from family / friends (P < 0.001), and sleep disturbance (P < 0.001), and number of ART regimen switches (P = 0.046) were associated with risk of depression, while neither sex nor transmission route showed any associations. There were no significant associations with HIV-specific clinical factors including current CD4(+) T cell count and current viral load. Conclusions: Prevalence of symptoms of anxiety and depression is high in this cohort of treatment-experienced HIV patients. Psychological and social-demographic factors, rather than HIV disease status, were associated with risk of depression and anxiety. This finding highlights the need to deliver interventions to address the mental health issues affecting HIV-infected persons with fully successful immune restoration across China.
Cohen YZ, Caskey M
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Broadly neutralizing antibodies for treatment and prevention of HIV-1 infection

CURRENT OPINION IN HIV AND AIDS 2018 JUL; 13(4):366-373
Purpose of reviewSeveral anti-HIV-1 broadly neutralizing antibodies (bNAbs) with exceptional breadth and potency that target different HIV-1 envelope epitopes have been identified. bNAbs are an attractive new strategy for HIV-1 prevention and therapy, and potentially, for long-term remission or cure. Here, we discuss findings from early clinical studies that have evaluated these novel bNAbs.Recent findingsPhase 1 studies of bNAbs targeting two distinct HIV-1 envelope epitopes have demonstrated their favorable safety and pharmacokinetic profile. Single bNAb infusions led to significant, but transient, decline in viremia with selection of escape variants. A single bNAb also delayed viral rebound in ART-treated participants who discontinued ART. Importantly, in-vivo efficacy was related to antibody potency and to the level of preexisting resistance. Studies in animal models showed that bNAbs can clear HIV-infected cells and modulate host immune responses. These findings suggest that bNAbs may target the latent HIV reservoir in humans and could contribute to long-term remission of HIV-1 infection.SummarybNAbs may offer advantages over traditional ART for both the prevention and treatment of HIV-1 infection. In addition, bNAbs may target the latent viral reservoir. bNAb combinations and bNAbs engineered for prolonged half-life and increased potency are currently undergoing clinical evaluation.
Willsey AJ, Morris MT, Wang S, Willsey HR, Sun NW, Teerikorpi N, Baum TB, Cagney G, Bender KJ, Desai TA, Srivastava D, Davis GW, Doudna J, Chang E, Sohal V, Lowenstein DH, Li H, Agard D, Keiser MJ, Shoichet B, von Zastrow M, Mucke L, Finkbeiner S, Gan L, Sestan N, Ward ME, Huttenhain R, Nowakowski TJ, Bellen HJ, Frank LM, Khokha MK, Lifton RP, Kampmann M, Ideker T, State MW, Krogan NJ
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The Psychiatric Cell Map Initiative: A Convergent Systems Biological Approach to Illuminating Key Molecular Pathways in Neuropsychiatric Disorders

CELL 2018 JUL 26; 174(3):505-520
Although gene discovery in neuropsychiatric disorders, including autism spectrum disorder, intellectual disability, epilepsy, schizophrenia, and Tourette disorder, has accelerated, resulting in a large number of molecular clues, it has proven difficult to generate specific hypotheses without the corresponding datasets at the protein complex and functional pathway level. Here, we describe one path forward-an initiative aimed at mapping the physical and genetic interaction networks of these conditions and then using these maps to connect the genomic data to neurobiology and, ultimately, the clinic. These efforts will include a team of geneticists, structural biologists, neurobiologists, systems biologists, and clinicians, leveraging a wide array of experimental approaches and creating a collaborative infrastructure necessary for long-term investigation. This initiative will ultimately intersect with parallel studies that focus on other diseases, as there is a significant overlap with genes implicated in cancer, infectious disease, and congenital heart defects.
Vittoria MA, Shenk EM, O'Rourke KP, Bolgioni AF, Lim S, Kacprzak V, Quinton RJ, Ganem NJ
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A genome-wide microRNA screen identifies regulators of tetraploid cell proliferation

MOLECULAR BIOLOGY OF THE CELL 2018 JUL 15; 29(14):1682-1692
Tetraploid cells, which are most commonly generated by errors in cell division, are genomically unstable and have been shown to promote tumorigenesis. Recent genomic studies have estimated that similar to 40% of all solid tumors have undergone a genome-doubling event during their evolution, suggesting a significant role for tetraploidy in driving the development of human cancers. To safeguard against the deleterious effects of tetraploidy, non-transformed cells that fail mitosis and become tetraploid activate both the Hippo and p53 tumor suppressor pathways to restrain further proliferation. Tetraploid cells must therefore overcome these antiproliferative barriers to ultimately drive tumor development. However, the genetic routes through which spontaneously arising tetraploid cells adapt to regain proliferative capacity remain poorly characterized. Here, we conducted a comprehensive gain-offunction genome-wide screen to identify microRNAs (miRNAs) that are sufficient to promote the proliferation of tetraploid cells. Our screen identified 23 miRNAs whose overexpression significantly promotes tetraploid proliferation. The vast majority of these miRNAs facilitate tetraploid growth by enhancing mitogenic signaling pathways (e.g., miR-191-3p); however, we also identified several miRNAs that impair the p53/p21 pathway (e.g., miR-523-3p), and a single miRNA (miR-24-3p) that potently inactivates the Hippo pathway via down-regulation of the tumor suppressor gene NF2. Collectively, our data reveal several avenues through which tetraploid cells may regain the proliferative capacity necessary to drive tumorigenesis.
Zhou Y, Kreek MJ
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Involvement of Activated Brain Stress Responsive Systems in Excessive and "Relapse" Alcohol Drinking in Rodent Models: Implications for Therapeutics

JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS 2018 JUL 1; 366(1):9-20
Addictive diseases, including addiction to alcohol, pose massive public health costs. Addiction is a chronic relapsing disease caused by both the direct effects induced by drugs and persistent neuroadaptations at the molecular, cellular, and behavioral levels. These drug-type specific neuroadaptations are brought on largely by the reinforcing effects of drugs on the central nervous system and environmental stressors. Results from animal experiments have demonstrated important interactions between alcohol and stressresponsive systems. Addiction to specific drugs such as alcohol, psychostimulants, and opioids shares some common direct or downstream effects on the brain's stress-responsive systems, including arginine vasopressin and its V1b receptors, dynorphin and the kappa-opioid receptors, pro-opiomelanocortin/beta-endorphin and the mu-opioid receptors, and the endocannabinoids. Further study of these systems through laboratory-based and translational research could lead to the discovery of novel treatment targets and the early optimization of interventions (for example, combination) for the pharmacologic therapy of alcoholism.
Balsevich G, Sticht M, Bowles NP, Singh A, Lee TTY, Li ZY, Chelikani PK, Lee FS, Borgland SL, Hillard CJ, McEwen BS, Hill MN
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Role for fatty acid amide hydrolase (FAAH) in the leptin-mediated effects on feeding and energy balance

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2018 JUL 17; 115(29):7605-7610
Endocannabinoid signaling regulates feeding and metabolic processes and has been linked to obesity development. Several hormonal signals, such as glucocorticoids and ghrelin, regulate feeding and metabolism by engaging the endocannabinoid system. Similarly, studies have suggested that leptin interacts with the endocannabinoid system, yet the mechanism and functional relevance of this interaction remain elusive. Therefore, we explored the interaction between leptin and endocannabinoid signaling with a focus on fatty acid amide hydrolase (FAAH), the primary degradative enzyme for the endocannabinoid N-arachidonoylethanolamine (anandamide; AEA). Mice deficient in leptin exhibited elevated hypothalamic AEA levels and reductions in FAAH activity while leptin administration to WT mice reduced AEA content and increased FAAH activity. Following high fat diet exposure, mice developed resistance to the effects of leptin administration on hypothalamic AEA content and FAAH activity. At a functional level, pharmacological inhibition of FAAH was sufficient to prevent leptin-mediated effects on body weight and food intake. Using a novel knock-in mouse model recapitulating a common human polymorphism (FAAH C385A; rs324420), which reduces FAAH activity, we investigated whether human genetic variance in FAAH affects leptin sensitivity. While WT (CC) mice were sensitive to leptin-induced reductions in food intake and body weight gain, low-expressing FAAH (AA) mice were unresponsive. These data demonstrate that FAAH activity is required for leptin's hypophagic effects and, at a translational level, suggest that a genetic variant in the FAAH gene contributes to differences in leptin sensitivity in human populations.
Shepherd SV, Freiwald WA
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Functional Networks for Social Communication in the Macaque Monkey

NEURON 2018 JUL 25; 99(2):413-420.e3
All primates communicate. To dissect the neural circuits of social communication, we used fMRI to map non- human primate brain regions for social perception, second- person (interactive) social cognition, and orofacial movement generation. Face perception, second- person cognition, and face motor networks were largely non- overlapping and acted as distinct functional units rather than an integrated feedforward- processing pipeline. Whereas secondperson context selectively engaged a region of medial prefrontal cortex, production of orofacial movements recruited distributed subcortical and cortical areas in medial and lateral frontal and insular cortex. These areas exhibited some specialization, but not dissociation, of function along the mediolateral axis. Production of lipsmack movements recruited areas including putative homologs of Broca's area. These findings provide a new view of the neural architecture for social communication and suggest expressive orofacial movements generated by lateral premotor cortex as a putative evolutionary precursor to human speech.
Han SY, Tan C, Ding JJ, Wang JL, Ma'ayan A, Gouon-Evans V
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Endothelial cells instruct liver specification of embryonic stem cell-derived endoderm through endothelial VEGFR2 signaling and endoderm epigenetic modifications

STEM CELL RESEARCH 2018 JUL; 30(?):163-170
Liver organogenesis requires complex cell-cell interactions between hepatic endoderm cells and adjacent cell niches. Endothelial cells are key players for endoderm hepatic fate decision. We previously demonstrated that the endothelial cell niche promotes hepatic specification of mouse embryonic stem cell(ESC)-derived endoderm through dual repression of Wnt and Notch pathways in endoderm cells. In the present study, we dissected further the mechanisms by which endothelial cells trigger endoderm hepatic specification. Using our previously established in vitro mouse ESC system mimicking the early hepatic specification process, endoderm cells were purified and co-cultured with endothelial cells to induce hepatic specification. The comparison of transcriptome profiles between hepatic endoderm cells isolated from co-cultures and endoderm cells cultured alone revealed that VEGF signaling instructs hepatic specification of endoderm cells through endothelial VEGFR2 activation. Additionally, epigenetic mark inhibition assays upon co-cultures uncovered that histone acetylation and DNA methylation promote hepatic specification while histone methylation inhibits it. This study provides an efficient 2D platform modelling the endothelial cell niche crosstalk with endoderm, and reveals mechanisms by which endothelial cells promote hepatic specification of mouse ESC-derived endoderm cells through endothelial VEGFR2 activation and endoderm epigenetic modifications.