Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 555
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Plant Cell ; 36(9): 3709-3728, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-38922302

RESUMO

Variation in gene expression levels is pervasive among individuals and races or varieties, and has substantial agronomic consequences, for example, by contributing to hybrid vigor. Gene expression level variation results from mutations in regulatory sequences (cis) and/or transcription factor (TF) activity (trans), but the mechanisms underlying cis- and/or trans-regulatory variation of complex phenotypes remain largely unknown. Here, we investigated gene expression variation mechanisms underlying the differential accumulation of the insecticidal compounds maysin and chlorogenic acid in silks of widely used maize (Zea mays) inbreds, B73 and A632. By combining transcriptomics and cistromics, we identified 1,338 silk direct targets of the maize R2R3-MYB TF Pericarp color1 (P1), consistent with it being a regulator of maysin and chlorogenic acid biosynthesis. Among these P1 targets, 464 showed allele-specific expression (ASE) between B73 and A632 silks. Allelic DNA-affinity purification sequencing identified 34 examples in which P1 allelic specific binding (ASB) correlated with cis-expression variation. From previous yeast one-hybrid studies, we identified 9 TFs potentially implicated in the control of P1 targets, with ASB to 83 out of 464 ASE genes (cis) and differential expression of 4 out of 9 TFs between B73 and A632 silks (trans). These results provide a molecular framework for understanding universal mechanisms underlying natural variation of gene expression levels, and how the regulation of metabolic diversity is established.


Assuntos
Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Zea mays , Zea mays/genética , Zea mays/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Alelos , Ácido Clorogênico/metabolismo , Fenótipo , Variação Genética
2.
Semin Cell Dev Biol ; 155(Pt B): 58-65, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-37423854

RESUMO

Thrombospondins (TSPs) belong to a functional class of ECM proteins called matricellular proteins that are not primarily structural, but instead influence cellular interactions within the local extracellular environment. The 3D arrangement of TSPs allow interactions with other ECM proteins, sequestered growth factors, and cell surface receptors. They are expressed in mesenchymal condensations and limb buds during skeletal development, but they are not required for patterning. Instead, when absent, there are alterations in musculoskeletal connective tissue ECM structure, organization, and function, as well as altered skeletal cell phenotypes. Both functional redundancies and unique contributions to musculoskeletal tissue structure and physiology are revealed in mouse models with compound TSP deletions. Crucial roles of individual TSPs are revealed during musculoskeletal injury and regeneration. The interaction of TSPs with mesenchymal stem cells (MSC), and their influence on cell fate, function, and ultimately, musculoskeletal phenotype, suggest that TSPs play integral, but as yet poorly understood roles in musculoskeletal health. Here, unique and overlapping contributions of trimeric TSP1/2 and pentameric TSP3/4/5 to musculoskeletal cell and matrix physiology are reviewed. Opportunities for new research are also noted.


Assuntos
Proteínas da Matriz Extracelular , Trombospondinas , Camundongos , Animais , Trombospondinas/genética , Trombospondinas/metabolismo , Esqueleto/metabolismo , Fenômenos Fisiológicos Celulares
3.
Genes Dev ; 32(17-18): 1201-1214, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30143526

RESUMO

The architectural and biochemical features of the plasma membrane are governed by its intimate association with the underlying cortical cytoskeleton. The neurofibromatosis type 2 (NF2) tumor suppressor merlin and closely related membrane:cytoskeleton-linking protein ezrin organize the membrane:cytoskeleton interface, a critical cellular compartment that both regulates and is regulated by growth factor receptors. An example of this poorly understood interrelationship is macropinocytosis, an ancient process of nutrient uptake and membrane remodeling that can both be triggered by growth factors and manage receptor availability. We show that merlin deficiency primes the membrane:cytoskeleton interface for epidermal growth factor (EGF)-induced macropinocytosis via a mechanism involving increased cortical ezrin, altered actomyosin, and stabilized cholesterol-rich membranes. These changes profoundly alter EGF receptor (EGFR) trafficking in merlin-deficient cells, favoring increased membrane levels of its heterodimerization partner, ErbB2; clathrin-independent internalization; and recycling. Our work suggests that, unlike Ras transformed cells, merlin-deficient cells do not depend on macropinocytic protein scavenging and instead exploit macropinocytosis for receptor recycling. Finally, we provide evidence that the macropinocytic proficiency of NF2-deficient cells can be used for therapeutic uptake. This work provides new insight into fundamental mechanisms of macropinocytic uptake and processing and suggests new ways to interfere with or exploit macropinocytosis in NF2 mutant and other tumors.


Assuntos
Membrana Celular/metabolismo , Fator de Crescimento Epidérmico/fisiologia , Receptores ErbB/metabolismo , Neurofibromina 2/fisiologia , Pinocitose , Actomiosina/metabolismo , Animais , Células Cultivadas , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Humanos , Camundongos , Neurofibromina 2/genética , Biossíntese de Proteínas
4.
PLoS Comput Biol ; 20(6): e1012178, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38829900

RESUMO

Striking progress has been made in understanding cognition by analyzing how the brain is engaged in different modes of information processing. For instance, so-called synergistic information (information encoded by a set of neurons but not by any subset) plays a key role in areas of the human brain linked with complex cognition. However, two questions remain unanswered: (a) how and why a cognitive system can become highly synergistic; and (b) how informational states map onto artificial neural networks in various learning modes. Here we employ an information-decomposition framework to investigate neural networks performing cognitive tasks. Our results show that synergy increases as networks learn multiple diverse tasks, and that in tasks requiring integration of multiple sources, performance critically relies on synergistic neurons. Overall, our results suggest that synergy is used to combine information from multiple modalities-and more generally for flexible and efficient learning. These findings reveal new ways of investigating how and why learning systems employ specific information-processing strategies, and support the principle that the capacity for general-purpose learning critically relies on the system's information dynamics.


Assuntos
Encéfalo , Cognição , Aprendizagem , Modelos Neurológicos , Redes Neurais de Computação , Humanos , Aprendizagem/fisiologia , Cognição/fisiologia , Encéfalo/fisiologia , Biologia Computacional , Neurônios/fisiologia
5.
Brain ; 147(1): 56-80, 2024 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-37703310

RESUMO

Integrating independent but converging lines of research on brain function and neurodevelopment across scales, this article proposes that serotonin 2A receptor (5-HT2AR) signalling is an evolutionary and developmental driver and potent modulator of the macroscale functional organization of the human cerebral cortex. A wealth of evidence indicates that the anatomical and functional organization of the cortex follows a unimodal-to-transmodal gradient. Situated at the apex of this processing hierarchy-where it plays a central role in the integrative processes underpinning complex, human-defining cognition-the transmodal cortex has disproportionately expanded across human development and evolution. Notably, the adult human transmodal cortex is especially rich in 5-HT2AR expression and recent evidence suggests that, during early brain development, 5-HT2AR signalling on neural progenitor cells stimulates their proliferation-a critical process for evolutionarily-relevant cortical expansion. Drawing on multimodal neuroimaging and cross-species investigations, we argue that, by contributing to the expansion of the human cortex and being prevalent at the apex of its hierarchy in the adult brain, 5-HT2AR signalling plays a major role in both human cortical expansion and functioning. Owing to its unique excitatory and downstream cellular effects, neuronal 5-HT2AR agonism promotes neuroplasticity, learning and cognitive and psychological flexibility in a context-(hyper)sensitive manner with therapeutic potential. Overall, we delineate a dual role of 5-HT2ARs in enabling both the expansion and modulation of the human transmodal cortex.


Assuntos
Córtex Cerebral , Receptor 5-HT2A de Serotonina , Adulto , Humanos , Encéfalo , Córtex Cerebral/fisiologia , Cognição/fisiologia , Neuroimagem
6.
J Neurovirol ; 30(2): 1-11, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38546936

RESUMO

Although older adults with HIV are at high risk for mild neurocognitive disorders, a subset experience successful cognitive aging (SCA). HIV is associated with an increased risk of vascular depression (VasDep), which can affect cognitive and daily functioning. The current study examined whether VasDep impedes SCA among older adults with HIV. 136 persons with HIV aged 50 years and older were classified as either SCA+ (n = 37) or SCA- (n = 99) based on a battery of demographically adjusted neurocognitive tests and self-reported cognitive symptoms. Participants were also stratified on the presence of vascular disease (e.g., hypertension) and current depression as determined by the Composite International Diagnostic Interview and the Depression/Dejection scale of the Profile of Mood States. A Cochran-Armitage test revealed a significant additive effect of vascular disease and depression on SCA in this sample of older adults with HIV (z = 4.13, p <.0001). Individuals with VasDep had the lowest frequency of SCA+ (0%), which differed significantly from the group with only vascular disease (30%, OR = 0.04, CI = 0.002,0.68)) and the group with neither vascular disease nor depression (47% OR = 0.02, CI = 0.33,0.001). Findings were not confounded by demographics, HIV disease severity, or other psychiatric and medical factors (ps > 0.05). These data suggest that presence of VasDep may be a barrier to SCA in older adults with HIV disease. Prospective, longitudinal studies with neuroimaging-based operationalizations of VasDep are needed to further clarify this risk factor's role in the maintenance of cognitive and brain health in persons with HIV disease.


Assuntos
Envelhecimento Cognitivo , Depressão , Infecções por HIV , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Infecções por HIV/complicações , Infecções por HIV/psicologia , Infecções por HIV/fisiopatologia , Infecções por HIV/virologia , Idoso , Depressão/fisiopatologia , Depressão/psicologia , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/virologia , Testes Neuropsicológicos , Doenças Vasculares/complicações , Doenças Vasculares/fisiopatologia , Fatores de Risco
7.
J Cardiovasc Electrophysiol ; 35(1): 155-161, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38010993

RESUMO

INTRODUCTION: The importance of atrio-ventricular synchrony pacing in sinus rhythm patients is known. To identify patients in whom leadless pacemakers are able to guarantee this atrio-ventricular synchrony, we explored correlations among echocardiographic measures of left atrial (LA) size and function (doppler parameter and strain) with A4 amplitude in patients implanted with new generation Micra-AV device. METHODS: After implantation with Micra-AV system, patients underwent device interrogation to evaluate AV synchrony based on the sensing of atrial mechanics and echocardiographic exam to assess LA morphology and LA function. RESULTS: In the 21 studied patients (14 males, 72 ± 13 years), the A4 wave amplitude values inversely correlated with LA antero-posterior diameter, LA volume, LA contraction strain and LA conduit strain, while they were positively related with LA reservoir strain. DISCUSSION: Our results indicate a statistically significant relationship between morphological echocardiographic LA parameters and atrial contraction signal (A4), detected by leadless pacemakers and used to synchronize ventricular pacing with the atrium. Instantaneous LA function assessment obtained with LA strain provides incremental information over morphological parameters. LA strain evaluates atrial myocardial deformation during the whole cardiac cycle. We found higher value of A4 in patients that have grater absolute value of LAsr, LAscd and LAsct, that are simple and measurable parameters of LA functional capacity. CONCLUSION: Preimplant echocardiographic evaluation of the atrial contractility may be useful in predicting adequate A4 sensing and consequently a good atrio-ventricular synchrony pacing. Echocardiography LA strain study seems promising in Micra-AV patient selection.


Assuntos
Átrios do Coração , Marca-Passo Artificial , Masculino , Humanos , Átrios do Coração/diagnóstico por imagem , Ventrículos do Coração , Ecocardiografia , Arritmias Cardíacas
8.
J Neurol Neurosurg Psychiatry ; 95(2): 151-157, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-37536925

RESUMO

BACKGROUND: Relapse risk after delivery is increased in women with active multiple sclerosis (MS), the best strategy to reduce it is unknown. We aimed to assess the association of four different postpartum strategies with relapses during the first 6 months post partum. METHODS: This cohort study includes data prospectively collected through structured telephone interviews from the German Multiple Sclerosis and Pregnancy Registry. Pregnancies with active MS (fingolimod or natalizumab treatment OR relapse within 1 year before pregnancy) and postpartum follow-up of ≥6 months were included. We compared four strategies: (1) intention to breastfeed exclusively without disease-modifying therapy (DMT) (exclusive breast feeding ≥2 months or switching to non-exclusive/weaning within 2 weeks after a relapse during the first 2 months), (2) early treatment with natalizumab/fingolimod and (3) other DMT initiated within 6 weeks post partum before a relapse. If women did not or only partially breastfed, or started DMT≤6 weeks after delivery after a relapse or later, we assumed (4) no-DMT-no-exclusive- breastfeeding-strategy. Main outcome was time to postpartum MS relapses. RESULTS: In 867 women with 911 pregnancies, most (n=416) intended to breastfeed exclusively or had no-DMT-no-exclusive-breastfeeding-strategy (n=290); fewer started fingolimod (n=38), natalizumab (n=74) or another DMT (n=93) early. Recurrent time-to-event analysis showed a statistically significant reduction in relapse hazard only with the natalizumab/fingolimod-strategy as of months 3-4 post partum compared with intention-to-breastfeed-exclusively-strategy. The very early relapse risk was highest in no-DMT-no-exclusive-breastfeeding-strategy. CONCLUSION: In active MS, an early postpartum treatment strategy should be determined well before delivery. Natalizumab/fingolimod-strategy reduced postpartum relapse hazard from month 3, but none diminished the early postpartum relapse hazard.


Assuntos
Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Gravidez , Feminino , Humanos , Esclerose Múltipla/tratamento farmacológico , Natalizumab/uso terapêutico , Estudos de Coortes , Cloridrato de Fingolimode/uso terapêutico , Período Pós-Parto , Recidiva , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Imunossupressores
9.
Brain ; 146(8): 3484-3499, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-36811945

RESUMO

Chronic post-concussive symptoms are common after mild traumatic brain injury (mTBI) and are difficult to predict or treat. Thalamic functional integrity is particularly vulnerable in mTBI and may be related to long-term outcomes but requires further investigation. We compared structural MRI and resting state functional MRI in 108 patients with a Glasgow Coma Scale (GCS) of 13-15 and normal CT, and 76 controls. We examined whether acute changes in thalamic functional connectivity were early markers for persistent symptoms and explored neurochemical associations of our findings using PET data. Of the mTBI cohort, 47% showed incomplete recovery 6 months post-injury. Despite the absence of structural changes, we found acute thalamic hyperconnectivity in mTBI, with specific vulnerabilities of individual thalamic nuclei. Acute fMRI markers differentiated those with chronic post-concussive symptoms, with time- and outcome-dependent relationships in a sub-cohort followed longitudinally. Moreover, emotional and cognitive symptoms were associated with changes in thalamic functional connectivity to known serotonergic and noradrenergic targets, respectively. Our findings suggest that chronic symptoms can have a basis in early thalamic pathophysiology. This may aid identification of patients at risk of chronic post-concussive symptoms following mTBI, provide a basis for development of new therapies and facilitate precision medicine application of these therapies.


Assuntos
Concussão Encefálica , Lesões Encefálicas , Síndrome Pós-Concussão , Humanos , Concussão Encefálica/complicações , Concussão Encefálica/diagnóstico por imagem , Síndrome Pós-Concussão/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Emoções , Imageamento por Ressonância Magnética , Encéfalo
10.
J Pediatr Psychol ; 49(7): 462-472, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38637284

RESUMO

OBJECTIVES: Low social standing and teasing are independently associated with increased body mass index (BMI) and overeating in children. However, children with low social status may be vulnerable to teasing. METHODS: We tested the statistical interaction of subjective social status (SSS) and subjective socioeconomic status (SSES) and teasing distress on BMI, fat mass index (FMI), and eating in the absence of hunger (EAH) in children (Mage = 13.09 years, SD = 2.50 years; 27.8% overweight/obese). Multiple linear regressions identified the main effects of self-reported SSS (compared to peers in school), distress due to teasing, and their interaction on BMI (n = 115), FMI (n = 114), and child- (n = 100) and parent-reported (n = 97) EAH. RESULTS: Teasing distress was associated with greater BMI, FMI, and child-reported EAH due to negative affect (a subscale of EAH) and total EAH scores. There were no associations of SSS with these outcomes. However, there was an interaction between SSS and teasing distress for BMI, FMI, and EAH from negative affect such that lower SSS was associated with higher BMI, FMI, and EAH from negative affect in the presence of teasing distress. However, there were no main effects or interactions (with teasing distress) of SSES on the outcomes. CONCLUSIONS: These findings suggest that the relationship between lower SSS and increased adiposity and overeating behaviors may be exacerbated by other threats to social standing, such as teasing. Children exposed to multiple social threats may be more susceptible to eating beyond physiological need and obesity than those who experience a single form of perceived social disadvantage.


Assuntos
Adiposidade , Índice de Massa Corporal , Autorrelato , Humanos , Feminino , Masculino , Adolescente , Adiposidade/fisiologia , Criança , Bullying/psicologia , Status Social , Fome , Obesidade Infantil/psicologia , Comportamento Alimentar/psicologia , Afeto , Angústia Psicológica
11.
Cogn Behav Neurol ; 37(1): 32-39, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-37871277

RESUMO

BACKGROUND: Executive dysfunction, which is common among persons with HIV (PWH), can have an adverse impact on health behaviors and quality of life. Intra-individual variability (IIV) is a measure of within-person variability across cognitive tests that is higher in PWH and is thought to reflect cognitive dyscontrol. OBJECTIVE: To assess whether cognitive IIV in the laboratory is associated with self-reported executive dysfunction in daily life among older PWH. METHOD: Participants included 71 PWH aged ≥50 years who completed six subtests from the Cogstate battery and two subscales from the Frontal Systems Behavior Scale (FrSBe; self-report version). Cognitive IIV was calculated from the Cogstate as the coefficient of variation derived from age-adjusted normative T scores. RESULTS: Cognitive IIV as measured by the Cogstate showed a significant, positive, medium-sized association with current FrSBe ratings of executive dysfunction but not disinhibition. CONCLUSION: Higher cognitive IIV in the laboratory as measured by the Cogstate may be related to the expression of HIV-associated symptoms of executive dysfunction in daily life for older PWH.


Assuntos
Disfunção Cognitiva , Infecções por HIV , Humanos , Idoso , Qualidade de Vida , Disfunção Cognitiva/complicações , Testes Neuropsicológicos , Cognição/fisiologia , Infecções por HIV/complicações
12.
Proc Natl Acad Sci U S A ; 118(30)2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34301891

RESUMO

Clinical research into consciousness has long focused on cortical macroscopic networks and their disruption in pathological or pharmacological consciousness perturbation. Despite demonstrating diagnostic utility in disorders of consciousness (DoC) and monitoring anesthetic depth, these cortico-centric approaches have been unable to characterize which neurochemical systems may underpin consciousness alterations. Instead, preclinical experiments have long implicated the dopaminergic ventral tegmental area (VTA) in the brainstem. Despite dopaminergic agonist efficacy in DoC patients equally pointing to dopamine, the VTA has not been studied in human perturbed consciousness. To bridge this translational gap between preclinical subcortical and clinical cortico-centric perspectives, we assessed functional connectivity changes of a histologically characterized VTA using functional MRI recordings of pharmacologically (propofol sedation) and pathologically perturbed consciousness (DoC patients). Both cohorts demonstrated VTA disconnection from the precuneus and posterior cingulate (PCu/PCC), a main default mode network node widely implicated in consciousness. Strikingly, the stronger VTA-PCu/PCC connectivity was, the more the PCu/PCC functional connectome resembled its awake configuration, suggesting a possible neuromodulatory relationship. VTA-PCu/PCC connectivity increased toward healthy control levels only in DoC patients who behaviorally improved at follow-up assessment. To test whether VTA-PCu/PCC connectivity can be affected by a dopaminergic agonist, we demonstrated in a separate set of traumatic brain injury patients without DoC that methylphenidate significantly increased this connectivity. Together, our results characterize an in vivo dopaminergic connectivity deficit common to reversible and chronic consciousness perturbation. This noninvasive assessment of the dopaminergic system bridges preclinical and clinical work, associating dopaminergic VTA function with macroscopic network alterations, thereby elucidating a critical aspect of brainstem-cortical interplay for consciousness.


Assuntos
Lesões Encefálicas Traumáticas/complicações , Tronco Encefálico/patologia , Conectoma , Transtornos da Consciência/patologia , Dopamina/metabolismo , Propofol/farmacologia , Área Tegmentar Ventral/patologia , Vigília/efeitos dos fármacos , Adolescente , Adulto , Idoso , Tronco Encefálico/efeitos dos fármacos , Estudos de Casos e Controles , Transtornos da Consciência/etiologia , Transtornos da Consciência/metabolismo , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Área Tegmentar Ventral/efeitos dos fármacos , Adulto Jovem
13.
Int J Mol Sci ; 25(17)2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39273438

RESUMO

With emerging genetic association studies, new genes and pathways are revealed as causative factors in the development of Parkinson's disease (PD). However, many of these PD genes are poorly characterized in terms of their function, subcellular localization, and interaction with other components in cellular pathways. This represents a major obstacle towards a better understanding of the molecular causes of PD, with deeper molecular studies often hindered by a lack of high-quality, validated antibodies for detecting the corresponding proteins of interest. In this study, we leveraged the nanoluciferase-derived LgBiT-HiBiT system by generating a cohort of tagged PD genes in both induced pluripotent stem cells (iPSCs) and iPSC-derived neuronal cells. To promote luminescence signals within cells, a master iPSC line was generated, in which LgBiT expression is under the control of a doxycycline-inducible promoter. LgBiT could bind to HiBiT when present either alone or when tagged onto different PD-associated proteins encoded by the genes GBA1, GPNMB, LRRK2, PINK1, PRKN, SNCA, VPS13C, and VPS35. Several HiBiT-tagged proteins could already generate luminescence in iPSCs in response to the doxycycline induction of LgBiT, with the enzyme glucosylceramidase beta 1 (GCase), encoded by GBA1, being one such example. Moreover, the GCase chaperone ambroxol elicited an increase in the luminescence signal in HiBiT-tagged GBA1 cells, correlating with an increase in the levels of GCase in dopaminergic cells. Taken together, we have developed and validated a Doxycycline-inducible luminescence system to serve as a sensitive assay for the quantification, localization, and activity of HiBiT-tagged PD-associated proteins with reliable sensitivity and efficiency.


Assuntos
Células-Tronco Pluripotentes Induzidas , Doença de Parkinson , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Glucosilceramidase/genética , Glucosilceramidase/metabolismo , alfa-Sinucleína/metabolismo , alfa-Sinucleína/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Neurônios/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo , Proteínas Quinases
14.
Neuroimage ; 269: 119926, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36740030

RESUMO

High-level brain functions are widely believed to emerge from the orchestrated activity of multiple neural systems. However, lacking a formal definition and practical quantification of emergence for experimental data, neuroscientists have been unable to empirically test this long-standing conjecture. Here we investigate this fundamental question by leveraging a recently proposed framework known as "Integrated Information Decomposition," which establishes a principled information-theoretic approach to operationalise and quantify emergence in dynamical systems - including the human brain. By analysing functional MRI data, our results show that the emergent and hierarchical character of neural dynamics is significantly diminished in chronically unresponsive patients suffering from severe brain injury. At a functional level, we demonstrate that emergence capacity is positively correlated with the extent of hierarchical organisation in brain activity. Furthermore, by combining computational approaches from network control theory and whole-brain biophysical modelling, we show that the reduced capacity for emergent and hierarchical dynamics in severely brain-injured patients can be mechanistically explained by disruptions in the patients' structural connectome. Overall, our results suggest that chronic unresponsiveness resulting from severe brain injury may be related to structural impairment of the fundamental neural infrastructures required for brain dynamics to support emergence.


Assuntos
Lesões Encefálicas , Conectoma , Fenômenos Fisiológicos do Sistema Nervoso , Humanos , Conectoma/métodos , Encéfalo , Imageamento por Ressonância Magnética/métodos
15.
Neuroimage ; 275: 120162, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37196986

RESUMO

Disorders of consciousness are complex conditions characterised by persistent loss of responsiveness due to brain injury. They present diagnostic challenges and limited options for treatment, and highlight the urgent need for a more thorough understanding of how human consciousness arises from coordinated neural activity. The increasing availability of multimodal neuroimaging data has given rise to a wide range of clinically- and scientifically-motivated modelling efforts, seeking to improve data-driven stratification of patients, to identify causal mechanisms for patient pathophysiology and loss of consciousness more broadly, and to develop simulations as a means of testing in silico potential treatment avenues to restore consciousness. As a dedicated Working Group of clinicians and neuroscientists of the international Curing Coma Campaign, here we provide our framework and vision to understand the diverse statistical and generative computational modelling approaches that are being employed in this fast-growing field. We identify the gaps that exist between the current state-of-the-art in statistical and biophysical computational modelling in human neuroscience, and the aspirational goal of a mature field of modelling disorders of consciousness; which might drive improved treatments and outcomes in the clinic. Finally, we make several recommendations for how the field as a whole can work together to address these challenges.


Assuntos
Lesões Encefálicas , Estado de Consciência , Humanos , Estado de Consciência/fisiologia , Transtornos da Consciência/diagnóstico por imagem , Lesões Encefálicas/complicações , Neuroimagem , Simulação por Computador
16.
Radiology ; 307(3): e222239, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36943075

RESUMO

Background Scar burden with late gadolinium enhancement (LGE) cardiac MRI (CMR) predicts arrhythmic events in patients with postinfarction in single-center studies. However, LGE analysis requires experienced human observers, is time consuming, and introduces variability. Purpose To test whether postinfarct scar with LGE CMR can be quantified fully automatically by machines and to compare the ability of LGE CMR scar analyzed by humans and machines to predict arrhythmic events. Materials and Methods This study is a retrospective analysis of the multicenter, multivendor CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DebrillAtor ThErapy (DERIVATE) registry. Patients with chronic heart failure, echocardiographic left ventricular ejection fraction (LVEF) of less than 50%, and LGE CMR were recruited (from January 2015 through December 2020). In the current study, only patients with ischemic cardiomyopathy were included. Quantification of total, dense, and nondense scars was carried out by two experienced readers or a Ternaus network, trained and tested with LGE images of 515 and 246 patients, respectively. Univariable and multivariable Cox analyses were used to assess patient and cardiac characteristics associated with a major adverse cardiac event (MACE). Area under the receiver operating characteristic curve (AUC) was used to compare model performances. Results In 761 patients (mean age, 65 years ± 11, 671 men), 83 MACEs occurred. With use of the testing group, univariable Cox-analysis found New York Heart Association class, left ventricle volume and/or function parameters (by echocardiography or CMR), guideline criterion (LVEF of ≤35% and New York Heart Association class II or III), and LGE scar analyzed by humans or the machine-learning algorithm as predictors of MACE. Machine-based dense or total scar conferred incremental value over the guideline criterion for the association with MACE (AUC: 0.68 vs 0.63, P = .02 and AUC: 0.67 vs 0.63, P = .01, respectively). Modeling with competing risks yielded for dense and total scar (AUC: 0.67 vs 0.61, P = .01 and AUC: 0.66 vs 0.61, P = .005, respectively). Conclusion In this analysis of the multicenter CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DebrillAtor ThErapy (DERIVATE) registry, fully automatic machine learning-based late gadolinium enhancement analysis reliably quantifies myocardial scar mass and improves the current prediction model that uses guideline-based risk criteria for implantable cardioverter defibrillator implantation. ClinicalTrials.gov registration no.: NCT03352648 Published under a CC BY 4.0 license. Supplemental material is available for this article.


Assuntos
Cicatriz , Meios de Contraste , Masculino , Humanos , Idoso , Volume Sistólico , Estudos Retrospectivos , Imagem Cinética por Ressonância Magnética/métodos , Gadolínio , Função Ventricular Esquerda , Imageamento por Ressonância Magnética/métodos , Sistema de Registros , Inteligência Artificial , Valor Preditivo dos Testes
17.
FASEB J ; 36(3): e22057, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35133020

RESUMO

Non-healing wounds are a major medical challenge, affecting over 6.5 million people in the US alone, with associated healthcare costs of about $16 billion annually. They can result in prolonged hospitalizations, work loss, disability, poor quality of life, and in diabetic patients with foot ulcers, amputation of the affected limb in 25% of patients. Though chronic ulcers may arise from different underlying diseases, the unifying feature is chronic infection, driving persistent inflammation that prolongs the healing process. One of the most frequently cultured or genetically identified pathogens in skin wounds is Pseudomonas aeruginosa. This species avidly forms biofilms in the wound that impede bacterial eradication by the host's immune mechanisms and limit efficacy of systemic antibiotics. Thus, non-antibiotic approaches to limit the growth and biofilm formation of this wound pathogen would be an advance in the treatment of chronic wounds. Prior work has demonstrated that the growth of other microbial species can be modulated by catecholamine agonists and antagonists of the adrenergic receptors (ARs). Here, we demonstrate that not only can the growth of this common wound pathogen be modulated by catecholamines, but also that the beta-AR antagonists can significantly decrease their growth, and importantly, limit their ability to form biofilms. These findings suggest that beta adrenergic antagonists may have a therapeutic role in the treatment of chronic skin wounds.


Assuntos
Antagonistas Adrenérgicos/farmacologia , Biofilmes , Epinefrina/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Timolol/farmacologia , Cicatrização , Antagonistas Adrenérgicos/uso terapêutico , Epinefrina/uso terapêutico , Humanos , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Dermatopatias Bacterianas/tratamento farmacológico , Dermatopatias Bacterianas/microbiologia , Timolol/uso terapêutico
18.
Mult Scler ; 29(3): 461-465, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36278327

RESUMO

BACKGROUND: As cladribine is contraindicated in pregnancy, data to pregnancy outcomes and disease control are scarce. OBJECTIVE: To investigate the effects of Cladribine use, in the last 6 months prior (56.4%) to or after (43.6%) the last menstrual period in a population of women with multiple sclerosis, on pregnancy outcomes and relapse rate during pregnancy and postpartum. METHODS: Data were collected prospectively in regular telephone interviews. RESULTS: Of 39 pregnancies, 27 babies have been born so far and one major congenital malformation occurred. Disease control was excellent among the cohort both during pregnancy and the postpartum period, with only one relapse recorded in each time period. CONCLUSIONS: Although most newborns are healthy, reinforced councelling on effective contraception 6 months after the last cladribine dosing is necessary.


Assuntos
Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Recém-Nascido , Gravidez , Feminino , Humanos , Cladribina , Estudos de Coortes , Resultado da Gravidez , Recidiva , Imunossupressores
19.
J Int Neuropsychol Soc ; 29(7): 677-685, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36750975

RESUMO

OBJECTIVES: People living with HIV (PLWH) often experience deficits in the strategic/executive aspects of prospective memory (PM) that can interfere with instrumental activities of daily living. This study used a conceptual replication design to determine whether cognitive intraindividual variability, as measured by dispersion (IIV-dispersion), contributes to PM performance and symptoms among PLWH. METHODS: Study 1 included 367 PLWH who completed a comprehensive clinical neuropsychological test battery, the Memory for Intentions Test (MIsT), and the Prospective and Retrospective Memory Questionnaire (PRMQ). Study 2 included 79 older PLWH who completed the Cogstate cognitive battery, the Cambridge Prospective Memory Test (CAMPROMPT), an experimental measure of time-based PM, and the PRMQ. In both studies, a mean-adjusted coefficient of variation was derived to measure IIV-dispersion using normative T-scores from the cognitive battery. RESULTS: Higher IIV-dispersion was significantly associated with lower time-based PM performance at small-to-medium effect sizes in both studies (mean r s  = -0.30). The relationship between IIV-dispersion and event-based PM performance was comparably small in magnitude in both studies (r s  = -0.19, -0.20), but it was only statistically significant in Study 1. IIV-dispersion showed very small, nonsignificant relationships with self-reported PM symptoms in both samples (r s < 0.10). CONCLUSIONS: Extending prior work in healthy adults, these findings suggest that variability in performance across a cognitive battery contributes to laboratory-based PM accuracy, but not perceived PM symptoms, among PLWH. Future studies might examine whether daily fluctuations in cognition or other aspects of IIV (e.g., inconsistency) play a role in PM failures in everyday life.


Assuntos
Infecções por HIV , Memória Episódica , Adulto , Humanos , Atividades Cotidianas/psicologia , Estudos Retrospectivos , Cognição , Testes Neuropsicológicos , Infecções por HIV/complicações
20.
J Water Health ; 21(9): 1228-1241, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37756191

RESUMO

Wastewater surveillance of SARS-CoV-2 has been used around the world to supplement clinical testing data for situational awareness of COVID-19 disease trends. Many regions of the world lack centralized wastewater collection and treatment infrastructure, which presents additional considerations for wastewater surveillance of SARS-CoV-2, including environmental decay of the RT-qPCR gene targets used for quantification of SARS-CoV-2 virions. Given the role of sunlight in the environmental decay of RNA, we evaluated sunlight photolysis kinetics of the N1 gene target in heat-inactivated SARS-CoV-2 with a solar simulator under laboratory conditions. Insignificant photolysis of the N1 target was observed in a photosensitizer-free matrix. Conversely, significant decay of the N1 target was observed in wastewater at a shallow depth (<1 cm). Given that sunlight irradiance is affected by several environmental factors, first-order decay rate models were used to evaluate the effect of water column depth, time of the year, and latitude on decay kinetics. Decay rate constants were found to decrease significantly with greater depth of the well-mixed water column, at high latitudes, and in the winter. Therefore, sunlight-mediated decay of the N1 gene target is likely to be minimal, and is unlikely to confound results from wastewater-based epidemiology programs utilizing wastewater-impacted surface waters.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Vigilância Epidemiológica Baseada em Águas Residuárias , Águas Residuárias , Fotólise , Luz Solar , Monitoramento Ambiental , Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA