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1.
Phys Rev Lett ; 131(7): 071002, 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37656847

RESUMO

Neutrinos remain mysterious. As an example, enhanced self-interactions (νSI), which would have broad implications, are allowed. At the high neutrino densities within core-collapse supernovae, νSI should be important, but robust observables have been lacking. We show that νSI make neutrinos form a tightly coupled fluid that expands under relativistic hydrodynamics. The outflow becomes either a burst or a steady-state wind; which occurs here is uncertain. Though the diffusive environment where neutrinos are produced may make a wind more likely, further work is needed to determine when each case is realized. In the burst-outflow case, νSI increase the duration of the neutrino signal, and even a simple analysis of SN 1987A data has powerful sensitivity. For the wind-outflow case, we outline several promising ideas that may lead to new observables. Combined, these results are important steps toward solving the 35-year-old puzzle of how νSI affect supernovae.

2.
Cell Rep ; 42(7): 112705, 2023 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-37393618

RESUMO

Defects in intestinal epithelial tight junctions (TJs) allow paracellular permeation of noxious luminal antigens and are important pathogenic factors in inflammatory bowel disease (IBD). We show that alpha-tocopherylquinone (TQ), a quinone-structured oxidation product of vitamin E, consistently enhances the intestinal TJ barrier by increasing barrier-forming claudin-3 (CLDN3) and reducing channel-forming CLDN2 in Caco-2 cell monolayers (in vitro), mouse models (in vivo), and surgically resected human colons (ex vivo). TQ reduces colonic permeability and ameliorates colitis symptoms in multiple colitis models. TQ, bifunctionally, activates both aryl hydrocarbon receptor (AhR) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways. Genetic deletion studies reveal that TQ-induced AhR activation transcriptionally increases CLDN3 via xenobiotic response element (XRE) in the CLDN3 promoter. Conversely, TQ suppresses CLDN2 expression via Nrf2-mediated STAT3 inhibition. TQ offers a naturally occurring, non-toxic intervention for enhancement of the intestinal TJ barrier and adjunct therapeutics to treat intestinal inflammation.


Assuntos
Claudinas , Colite , Camundongos , Animais , Humanos , Claudinas/metabolismo , Células CACO-2 , Fator 2 Relacionado a NF-E2/metabolismo , Mucosa Intestinal/metabolismo , Junções Íntimas/metabolismo , Receptores de Hidrocarboneto Arílico/genética , Colite/metabolismo , Vitamina E/metabolismo , Permeabilidade
3.
Per Med ; 19(6): 535-548, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36317592

RESUMO

Aim: To elicit preferences for pharmacogenomic (PGx) testing in polypharmacy patients. Materials & methods: A face-to-face discrete choice experiment survey was designed and administered to adult polypharmacy patients recruited at a local retail pharmacy in Albuquerque (NM, USA). Results: A total of 128 eligible polypharmacy patients completed the discrete choice experiment survey and significantly preferred a PGx test with lower cost, better confidentiality and higher certainty of identifying best medication/dose and side effects and one that can be used to advocate for their treatment needs (all p < 0.01). Conclusion: This is the first study eliciting preferences for PGx testing among polypharmacy patients. The study found most polypharmacy patients were willing to take a PGx test and their preferences were mostly influenced by test cost.


Patients who concurrently take five or more medications are at a higher risk of experiencing side effects related to drug­drug/drug­gene interactions. 'One size doesn't fit all' ­ individuals may respond differently to the same dose of a medication. Pharmacogenomic (PGx) testing identifies individual genetic information that may help explain better or worse outcomes or potential problems with drug therapies and eventually may help optimize patient treatment. The authors conducted a face-to-face survey to assess preferences for PGx testing in polypharmacy patients and found that most polypharmacy patients were willing to take a PGx test and their preferences were mostly influenced by test cost and performance, as well as the confidentiality of test results.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Testes Farmacogenômicos , Adulto , Humanos , Polimedicação , Farmacogenética , Confidencialidade
4.
Cortex ; 154: 77-88, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35759817

RESUMO

As transcranial electrical stimulation (tES) protocols advance, assumptions underlying the technique need to be retested to ensure they still hold. Whilst the safety of stimulation has been demonstrated mainly for a small number of sessions, and small sample size, adverse events (AEs) following multiple sessions remain largely untested. Similarly, whilst blinding procedures are typically assumed to be effective, the effect of multiple stimulation sessions on the efficacy of blinding procedures also remains under question. This is especially relevant in multisite projects where small unintentional variations in protocol could lead to inter-site difference. We report AE and blinding data from 1,019 participants who received up to 11 semi-consecutive sessions of active or sham transcranial alternating current stimulation (tACS), direct current stimulation (tDCS), and random noise stimulation (tRNS), at 4 sites in the UK and US. We found that AEs were often best predicted by factors other than tES, such as testing site or session number. Results from the blinding analysis suggested that blinding was less effective for tDCS and tACS than tRNS. The occurrence of AEs did not appear to be linked to tES despite the use of smaller electrodes or repeated delivery. However, blinding efficacy was impacted in tES conditions with higher cutaneous sensation, highlighting a need for alternative stimulation blinding protocols. This may be increasingly necessary in studies wishing to deliver stimulation with higher intensities.


Assuntos
Estimulação Transcraniana por Corrente Contínua , Humanos , Sensação , Pele
6.
Nat Neurosci ; 23(12): 1597-1605, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33230328

RESUMO

When people are forced to be isolated from each other, do they crave social interactions? To address this question, we used functional magnetic resonance imaging to measure neural responses evoked by food and social cues after participants (n = 40) experienced 10 h of mandated fasting or total social isolation. After isolation, people felt lonely and craved social interaction. Midbrain regions showed selective activation to food cues after fasting and to social cues after isolation; these responses were correlated with self-reported craving. By contrast, striatal and cortical regions differentiated between craving food and craving social interaction. Across deprivation sessions, we found that deprivation narrows and focuses the brain's motivational responses to the deprived target. Our results support the intuitive idea that acute isolation causes social craving, similar to the way fasting causes hunger.


Assuntos
Fissura/fisiologia , Fome/fisiologia , Mesencéfalo/fisiologia , Isolamento Social/psicologia , Adolescente , Adulto , Mapeamento Encefálico , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Sinais (Psicologia) , Jejum/psicologia , Feminino , Alimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Mesencéfalo/diagnóstico por imagem , Motivação , Neostriado/diagnóstico por imagem , Neostriado/fisiologia , Meio Social , Área Tegmentar Ventral/fisiologia , Adulto Jovem
7.
Philos Trans A Math Phys Eng Sci ; 378(2180): 20190301, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32811358

RESUMO

This review assesses the current state of knowledge of how the elements were produced in the Big Bang, in stellar lives and deaths, and by interactions in interstellar gas. We begin with statements of fact and discuss the evidence that convinced astronomers that the Sun is fusing hydrogen, that low-mass stars produce heavy elements through neutron capture, that massive stars can explode as supernovae and that supernovae of all types produce new elements. Nucleosynthesis in the Big Bang, through cosmic ray spallation, and in exploding white dwarfs is only ranked below the above facts in certainty because the evidence, while overwhelming, is so far circumstantial. Next, we highlight the flaws in our current understanding of the predictions for lithium production in the Big Bang and/or its destruction in stars and for the production of the elements with atomic number [Formula: see text]. While the theory that neutron star mergers produce elements through neutron-capture has powerful circumstantial evidence, we are unconvinced that they produce all of the elements past nickel. Also in dispute is the exact mechanism or mechanisms that cause the white dwarfs to explode. It is difficult to determine the origin of rare isotopes because signatures of their production are weak. We are uncertain about the production sites of some lithium and nitrogen isotopes and proton-rich heavy nuclei. Finally, Betelgeuse is probably not the next star to become a supernovae in the Milky Way, in part because Betelgeuse may collapse directly to a black hole instead. The accumulated evidence in this review shows that we understand the major production sites for the elements, but islands of uncertainty in the periodic table exist. Resolving these uncertainties requires in particular understanding explosive events with compact objects and understanding the nature of the first stars and is therefore primed for new discoveries in the next decades. This article is part of the theme issue 'Mendeleev and the periodic table'.

8.
Science ; 368(6491)2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32381689

RESUMO

Van den Heuvel and Tauris argue that if the red giant star in the system 2MASS J05215658+4359220 has a mass of 1 solar mass (M ☉), then its unseen companion could be a binary composed of two 0.9 M ☉ stars, making a triple system. We contend that the existing data are most consistent with a giant of mass [Formula: see text] M ☉, implying a black hole companion of [Formula: see text] M ☉.

9.
Front Pharmacol ; 11: 308, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32226386

RESUMO

Autophagy is a cellular degradative process that has multiple important actions in cancer. Autophagy modulation is under consideration as a promising new approach to cancer therapy. However, complete autophagy dysregulation is likely to have substantial undesirable side effects. Thus, more targeted approaches to autophagy modulation may prove clinically beneficial. One potential avenue to achieving this goal is to focus on the actions of tripartite motif-containing protein family members (TRIMs). TRIMs have key roles in an array of cellular processes, and their dysregulation has been extensively linked to cancer risk and prognosis. As detailed here, emerging data shows that TRIMs can play important yet context-dependent roles in controlling autophagy and in the selective targeting of autophagic substrates. This review covers how the autophagy-related actions of TRIM proteins contribute to cancer and the possibility of targeting TRIM-directed autophagy in cancer therapy.

10.
Science ; 366(6465): 637-640, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31672898

RESUMO

Black hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radial velocity and photometric variability data to show that the bright, rapidly rotating giant star 2MASS J05215658+4359220 is in a binary system with a massive unseen companion. The system has an orbital period of ~83 days and near-zero eccentricity. The photometric variability period of the giant is consistent with the orbital period, indicating star spots and tidal synchronization. Constraints on the giant's mass and radius imply that the unseen companion is [Formula: see text] solar masses, indicating that it is a noninteracting low-mass black hole or an unexpectedly massive neutron star.

11.
PLoS One ; 11(12): e0169107, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28036366

RESUMO

Lung cancer has the highest mortality rate of any tissue-specific cancer in both men and women. Research continues to investigate novel drugs and therapies to mitigate poor treatment efficacy, but the lack of a good descriptive lung cancer animal model for preclinical drug evaluation remains an obstacle. Here we describe the development of an orthotopic lung cancer animal model which utilizes the human sodium iodide symporter gene (hNIS; SLC5A5) as an imaging reporter gene for the purpose of non-invasive, longitudinal tumor quantification. hNIS is a glycoprotein that naturally transports iodide (I-) into thyroid cells and has the ability to symport the radiotracer 99mTc-pertechnetate (99mTcO4-). A549 lung adenocarcinoma cells were genetically modified with plasmid or lentiviral vectors to express hNIS. Modified cells were implanted into athymic nude mice to develop two tumor models: a subcutaneous and an orthotopic xenograft tumor model. Tumor progression was longitudinally imaged using SPECT/CT and quantified by SPECT voxel analysis. hNIS expression in lung tumors was analyzed by quantitative real-time PCR. Additionally, hematoxylin and eosin staining and visual inspection of pulmonary tumors was performed. We observed that lentiviral transduction provided enhanced and stable hNIS expression in A549 cells. Furthermore, 99mTcO4- uptake and accumulation was observed within lung tumors allowing for imaging and quantification of tumor mass at two-time points. This study illustrates the development of an orthotopic lung cancer model that can be longitudinally imaged throughout the experimental timeline thus avoiding inter-animal variability and leading to a reduction in total animal numbers. Furthermore, our orthotopic lung cancer animal model is clinically relevant and the genetic modification of cells for SPECT/CT imaging can be translated to other tissue-specific tumor animal models.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico , Simportadores/genética , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada por Raios X/métodos , Células A549 , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Iodetos/metabolismo , Neoplasias Pulmonares/genética , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Pertecnetato Tc 99m de Sódio/metabolismo , Simportadores/metabolismo , Transplante Heterólogo , Carga Tumoral/genética
12.
Cancer Med ; 5(11): 3336-3345, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27748080

RESUMO

Autophagy has been linked with melanoma risk and survival, but no polymorphisms in autophagy-related (ATG) genes have been investigated in relation to melanoma progression. We examined five single-nucleotide polymorphisms (SNPs) in three ATG genes (ATG5; ATG10; and ATG16L) with known or suspected impact on autophagic flux in an international population-based case-control study of melanoma. DNA from 911 melanoma patients was genotyped. An association was identified between (GG) (rs2241880) and earlier stage at diagnosis (OR 0.47; 95% Confidence Intervals (CI) = 0.27-0.81, P = 0.02) and a decrease in Breslow thickness (P = 0.03). The ATG16L heterozygous genotype (AG) (rs2241880) was associated with younger age at diagnosis (P = 0.02). Two SNPs in ATG5 were found to be associated with increased stage (rs2245214 CG, OR 1.47; 95% CI = 1.11-1.94, P = 0.03; rs510432 CC, OR 1.84; 95% CI = 1.12-3.02, P = 0.05). Finally, we identified inverse associations between ATG5 (GG rs2245214) and melanomas on the scalp or neck (OR 0.20, 95% CI = 0.05-0.86, P = 0.03); ATG10 (CC) (rs1864182) and brisk tumor infiltrating lymphocytes (TILs) (OR 0.42; 95% CI = 0.21-0.88, P = 0.02), and ATG5 (CC) (rs510432) with nonbrisk TILs (OR 0.55; 95% CI = 0.34-0.87, P = 0.01). Our data suggest that ATG SNPs might be differentially associated with specific host and tumor characteristics including age at diagnosis, TILs, and stage. These associations may be critical to understanding the role of autophagy in cancer, and further investigation will help characterize the contribution of these variants to melanoma progression.


Assuntos
Autofagia/genética , Predisposição Genética para Doença , Variação Genética , Melanoma/epidemiologia , Melanoma/genética , Vigilância da População , Adulto , Idoso , Alelos , Proteínas Relacionadas à Autofagia/genética , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Estadiamento de Neoplasias , Razão de Chances , Polimorfismo de Nucleotídeo Único
13.
PLoS One ; 11(3): e0151525, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26986969

RESUMO

Tocopherylquinone (TQ), the oxidation product of alpha-tocopherol (AT), is a bioactive molecule with distinct properties from AT. In this study, AT and TQ are investigated for their comparative effects on growth and androgenic activity in prostate cancer cells. TQ potently inhibited the growth of androgen-responsive prostate cancer cell lines (e.g., LAPC4 and LNCaP cells), whereas the growth of androgen-independent prostate cancer cells (e.g., DU145 cells) was not affected by TQ. Due to the growth inhibitory effects induced by TQ on androgen-responsive cells, the anti-androgenic properties of TQ were examined. TQ inhibited the androgen-induced activation of an androgen-responsive reporter and inhibited the release of prostate specific antigen from LNCaP cells. TQ pretreatment was also found to inhibit AR activation as measured using the Multifunctional Androgen Receptor Screening assay. Furthermore, TQ decreased androgen-responsive gene expression, including TM4SF1, KLK2, and PSA over 5-fold, whereas AT did not affect the expression of androgen-responsive genes. Of importance, the antiandrogenic effects of TQ on prostate cancer cells were found to result from androgen receptor protein down-regulation produced by TQ that was not observed with AT treatment. Moreover, none of the androgenic endpoints assessed were affected by AT. The down-regulation of androgen receptor protein by TQ was abrogated by co-treatment with antioxidants. Overall, the biological actions of TQ were found to be distinct from AT, where TQ was found to be a potent inhibitor of cell growth and androgenic activity in androgen-responsive prostate cancer cells.


Assuntos
Androgênios/farmacologia , Antioxidantes/farmacologia , Receptores Androgênicos/metabolismo , Vitamina E/análogos & derivados , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Immunoblotting , Imuno-Histoquímica , Masculino , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Receptores Androgênicos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Vitamina E/farmacologia , alfa-Tocoferol/farmacologia
14.
J Cogn Neurosci ; 28(4): 575-88, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26741799

RESUMO

Working memory is central to human cognition, and intensive cognitive training has been shown to expand working memory capacity in a given domain. It remains unknown, however, how the neural systems that support working memory are altered through intensive training to enable the expansion of working memory capacity. We used fMRI to measure plasticity in activations associated with complex working memory before and after 20 days of training. Healthy young adults were randomly assigned to train on either a dual n-back working memory task or a demanding visuospatial attention task. Training resulted in substantial and task-specific expansion of dual n-back abilities accompanied by changes in the relationship between working memory load and activation. Training differentially affected activations in two large-scale frontoparietal networks thought to underlie working memory: the executive control network and the dorsal attention network. Activations in both networks linearly scaled with working memory load before training, but training dissociated the role of the two networks and eliminated this relationship in the executive control network. Load-dependent functional connectivity both within and between these two networks increased following training, and the magnitudes of increased connectivity were positively correlated with improvements in task performance. These results provide insight into the adaptive neural systems that underlie large gains in working memory capacity through training.


Assuntos
Mapeamento Encefálico , Lobo Frontal/fisiologia , Aprendizagem/fisiologia , Memória de Curto Prazo/fisiologia , Lobo Parietal/fisiologia , Adolescente , Adulto , Análise de Variância , Feminino , Lobo Frontal/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Modelos Lineares , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Vias Neurais/diagnóstico por imagem , Oxigênio/sangue , Lobo Parietal/diagnóstico por imagem , Tempo de Reação/fisiologia , Adulto Jovem
15.
Cortex ; 64: 271-80, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25562175

RESUMO

We examined how variation in working memory (WM) capacity due to aging or individual differences among young adults is associated with intrinsic or resting-state anticorrelations, particularly between (1) the medial prefrontal cortex (MPFC), a component of the default-mode network (DMN) that typically decreases in activation during external, attention-demanding tasks, and (2) the dorsolateral prefrontal cortex (DLPFC), a component of the fronto-parietal control network that supports executive functions and WM and typically increases in activation during attention-demanding tasks. We compared the magnitudes of MPFC-DLPFC anticorrelations between healthy younger and older participants (Experiment 1) and related the magnitudes of these anticorrelations to individual differences on two behavioral measures of WM capacity in two independent groups of young adults (Experiments 1 and 2). Relative to younger adults, older adults exhibited reductions in WM capacity and in MPFC-DLPFC anticorrelations. Within younger adults, greater MPFC-DLPFC anticorrelation at rest correlated with greater WM capacity. These findings show that variation in MPFC-DLPFC anticorrelations, whether related to aging or to individual differences, may reflect an intrinsic functional brain architecture supportive of WM capacity.


Assuntos
Envelhecimento/fisiologia , Lateralidade Funcional/fisiologia , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Córtex Pré-Frontal/fisiologia , Descanso/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Encefálico , Feminino , Neuroimagem Funcional , Humanos , Individualidade , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Leitura , Adulto Jovem
16.
PLoS One ; 8(5): e63614, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23717453

RESUMO

Fluid intelligence is important for successful functioning in the modern world, but much evidence suggests that fluid intelligence is largely immutable after childhood. Recently, however, researchers have reported gains in fluid intelligence after multiple sessions of adaptive working memory training in adults. The current study attempted to replicate and expand those results by administering a broad assessment of cognitive abilities and personality traits to young adults who underwent 20 sessions of an adaptive dual n-back working memory training program and comparing their post-training performance on those tests to a matched set of young adults who underwent 20 sessions of an adaptive attentional tracking program. Pre- and post-training measurements of fluid intelligence, standardized intelligence tests, speed of processing, reading skills, and other tests of working memory were assessed. Both training groups exhibited substantial and specific improvements on the trained tasks that persisted for at least 6 months post-training, but no transfer of improvement was observed to any of the non-trained measurements when compared to a third untrained group serving as a passive control. These findings fail to support the idea that adaptive working memory training in healthy young adults enhances working memory capacity in non-trained tasks, fluid intelligence, or other measures of cognitive abilities.


Assuntos
Cognição/fisiologia , Inteligência/fisiologia , Memória de Curto Prazo/fisiologia , Adulto , Educação/métodos , Feminino , Humanos , Masculino , Leitura , Adulto Jovem
17.
J Neurophysiol ; 109(5): 1250-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23236006

RESUMO

We used real-time functional magnetic resonance imaging (fMRI) to determine which regions of the human brain have a role in vigilance as measured by reaction time (RT) to variably timed stimuli. We first identified brain regions where activation before stimulus presentation predicted RT. Slower RT was preceded by greater activation in the default-mode network, including lateral parietal, precuneus, and medial prefrontal cortices; faster RT was preceded by greater activation in the supplementary motor area (SMA). We examined the roles of these brain regions in vigilance by triggering trials based on brain states defined by blood oxygenation level-dependent activation measured using real-time fMRI. When activation of relevant neural systems indicated either a good brain state (increased activation of SMA) or a bad brain state (increased activation of lateral parietal cortex and precuneus) for performance, a target was presented and RT was measured. RTs on trials triggered by a good brain state were significantly faster than RTs on trials triggered by a bad brain state. Thus human performance was controlled by monitoring brain states that indicated high or low vigilance. These findings identify neural systems that have a role in vigilance and provide direct evidence that the default-mode network has a role in human performance. The ability to control and enhance human behavior based on brain state may have broad implications.


Assuntos
Nível de Alerta/fisiologia , Córtex Motor/fisiologia , Rede Nervosa/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Lobo Parietal/fisiologia , Córtex Pré-Frontal/fisiologia , Desempenho Psicomotor , Tempo de Reação
18.
Front Hum Neurosci ; 6: 187, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22737117

RESUMO

Humans survive in environments that contain a vast quantity and variety of visual information. All items of perceived visual information must be represented within a limited number of brain networks. The human brain requires mechanisms for selecting only a relevant fraction of perceived information for more in-depth processing, where neural representations of that information may be actively maintained and utilized for goal-directed behavior. Object-based attention is crucial for goal-directed behavior and yet remains poorly understood. Thus, in the study we investigate how neural representations of visual object information are guided by selective attention. The magnitude of activation in human extrastriate cortex has been shown to be modulated by attention; however, object-based attention is not likely to be fully explained by a localized gain mechanism. Thus, we measured information coded in spatially distributed patterns of brain activity with fMRI while human participants performed a task requiring selective processing of a relevant visual object category that differed across conditions. Using pattern classification and spatial correlation techniques, we found that the direction of selective attention is implemented as a shift in the tuning of object-based information representations within extrastriate cortex. In contrast, we found that representations within lateral prefrontal cortex (PFC) coded for the attention condition rather than the concrete representations of object category. In sum, our findings are consistent with a model of object-based selective attention in which representations coded within extrastriate cortex are tuned to favor the representation of goal-relevant information, guided by more abstract representations within lateral PFC.

19.
Toxicol Lett ; 209(2): 161-5, 2012 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-22222162

RESUMO

Breast cancer is the most common cancer and the second leading cause of cancer-related mortality worldwide. The etiology of breast cancer is very diverse and ethanol (EtOH) consumption is a well-established risk factor for breast cancer in women. However, the mechanism by which EtOH exerts its carcinogenic activity in breast tissue remains unknown. CYP2E1 is known to metabolize ethanol and produce reactive oxygen species (ROS), including superoxide in epithelial cells. Therefore, in the present studies, we investigated whether there is an increase in ROS following overexpression of CYP2E1 in MCF-10A cells. We found that 30 and 100 mM EtOH increased ROS levels after 2 h treatment in CYP2E1 overexpressing cells. Based on these results and our previous studies with ROS-producing chemicals, we also examined epidermal growth factor receptor (EGFR) activation following exposure to ethanol. We found that there was an increase in phosphorylation of pY1086 EGFR after 18 h EtOH treatment in CYP2E1 overexpressing cells. These studies support a hypothesis that EtOH might increase human mammary cell activation, via an EGFR-dependent signaling mechanism associated with oxidative stress.


Assuntos
Neoplasias da Mama/induzido quimicamente , Neoplasias da Mama/metabolismo , Citocromo P-450 CYP2E1/biossíntese , Receptores ErbB/metabolismo , Etanol/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Western Blotting , Neoplasias da Mama/enzimologia , Linhagem Celular Tumoral , Citocromo P-450 CYP2E1/genética , Citocromo P-450 CYP2E1/metabolismo , Feminino , Humanos , Fosforilação/efeitos dos fármacos , Transfecção
20.
Prostate ; 72(6): 612-25, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21796654

RESUMO

BACKGROUND: The androgen receptor (AR) plays a critical role in prostate cancer development and progression. Therefore, the inhibition of AR function is an established therapeutic intervention. Since the expression of the AR is retained and often increased in progressive disease, AR protein down-regulation is a promising therapeutic approach against prostate cancer. We show here that the curcumin analog 27 (ca27) down-regulates AR expression in several prostate cancer cell lines. METHODS: ca27 at low micromolar concentrations was tested for its effect on AR expression, AR activation, and induction of oxidative stress in human LNCaP, C4-2, and LAPC-4 prostate cancer cells. RESULTS: ca27 induced the down-regulation of AR protein expression in LNCaP, C4-2, and LAPC-4 cells within 12 hr. Further, ca27 led to the rapid induction of reactive oxygen species (ROS). To further support this finding, ca27 treatment led to the activation of the cellular redox sensor NF-E2-related factor 2 (Nrf2) and the induction of the Nrf2-regulated genes NAD(P)H quinone oxidoreductase 1 and aldoketoreductase 1C1. We show that ROS production preceded AR protein loss and that ca27-mediated down-regulation of the AR was attenuated by the antioxidant, N-acetyl cysteine. CONCLUSIONS: ca27 induces ROS and mediates AR protein down-regulation through an oxidative stress mechanism of action. Our results suggest that ca27 represents a novel agent for the elucidation of mechanisms of AR down-regulation, which could lead to effective new anti-androgenic strategies for the treatment of advanced prostate cancer.


Assuntos
Curcumina/análogos & derivados , Regulação para Baixo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Curcumina/farmacologia , Humanos , Masculino , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Receptores Androgênicos/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética
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