Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 157
Filtrar
1.
Molecules ; 29(16)2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39202966

RESUMO

The Japanese plum tree (Prunus salicina Lindl.) is mainly cultivated in temperate areas of China and some European countries. Certain amounts of wood (from pruning works) are generated every year from this crop of worldwide commercial significance. The main objective of this work was to value this agricultural woody residue, for which the chemical composition of pruning wood extracts from six Japanese plum cultivars was investigated, and the antiproliferative activity of extracts and pure phenolics present in those extracts was measured. For the chemical characterization, total phenolic content and DPPH radical-scavenging assays and HPLC‒DAD/ESI‒MS analyses were performed, with the procyanidin (-)-ent-epicatechin-(2α→O→7,4α→8)-epicatechin (5) and the propelargonidin (+)-epiafzelechin-(2ß→O→7,4ß→8)-epicatechin (7) being the major components of the wood extracts. Some quantitative differences were found among plum cultivars, and the content of proanthocyanidins ranged from 1.50 (cv. 'Fortune') to 4.44 (cv. 'Showtime') mg/g of dry wood. Regarding the antitumoral activity, eight wood extracts and four phenolic compounds were evaluated in MCF-7 cells after 48 h of induction, showing the wood extract from cv. 'Songold' and (‒)-annphenone (3), the best antiproliferative activity (IC50: 424 µg/mL and 405 µg/mL, respectively).


Assuntos
Extratos Vegetais , Madeira , Humanos , Madeira/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Proliferação de Células/efeitos dos fármacos , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/química , Prunus domestica/química , Fenóis/química , Fenóis/farmacologia , Fenóis/análise , Cromatografia Líquida de Alta Pressão , Células MCF-7 , Prunus/química , Linhagem Celular Tumoral , Antineoplásicos/farmacologia , Antineoplásicos/química , Antioxidantes/farmacologia , Antioxidantes/química
2.
Chem Biodivers ; 20(5): e202200931, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37017495

RESUMO

European plum tree (Prunus domestica L.) is cultivated in many countries for its delicious and nutritive fruit and, accordingly, certain amounts of wood (from pruning works) are generated every year. The main objective of this work was to value this agricultural woody residue, for which the chemical composition of pruning wood extracts from four European plum cultivars was investigated, and the human lactate dehydrogenase A (hLDHA) inhibitory activity of plum wood extracts and pure proanthocyanidins present in those extracts was measured. For the chemical characterization, total phenolic content and DPPH radical-scavenging assays and HPLC-DAD/ESI-MS analyses were performed, the procyanidin (-)-ent-epicatechin-(2α→O→7,4α→8)-catechin (4), the phenolic glucoside (-)-annphenone (3) and the flavan-3-ol catechin (1) being the major components of the wood extracts. Some quantitative and qualitative differences were found among plum cultivars, and the content of proanthocyanidins ranged from 1.51 (cv. 'Claudia de Tolosa') to 8.51 (cv. 'De la Rosa') mg g-1 of dry wood. For the hLDHA inhibitory activity, six wood extracts and six proanthocyanidins were evaluated by a UV spectrophotometric assay, compound 4 showing the highest inhibitory activity (IC50 3.2 µM) of this enzyme involved on the excessive production of oxalate in the liver of patients affected by the rare disease Primary Hyperoxaluria.


Assuntos
Catequina , Proantocianidinas , Prunus domestica , Humanos , Prunus domestica/química , Proantocianidinas/farmacologia , Catequina/farmacologia , Madeira/química , Extratos Vegetais/química , Frutas/química
3.
Mikrochim Acta ; 190(6): 203, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37156867

RESUMO

The potential applications of electroanalytical techniques for the quantification and size characterization of nonelectroactive polystyrene microplastics is reported, in addition to characterizing the kinetics of adsorption of bisphenol A on these polystyrene microparticles. The individual adsorption events of very diluted polystyrene microparticles dispersions on glassy-carbon microelectrodes produce the blocking of the charge transfer of a mediator (ferrocene-methanol) thus decreasing the current of the recorded chronoamperogram in a stepwise manner. The magnitude of the current steps are in the order of pA values and can be related to the diameter of the plastic microparticles in the size range 0.1 to 10 µm. The frequency of the current steps in the domain time used (120 s) allows to quantify the number concentration of these microparticles in the range 0.005 to 0.500 pM. Electrochemical impedance spectroscopy confirms the adsorption of the polystyrene microplastics on carbon microelectrodes (and to a lesser extent on platinum microelectrodes) under the same experimental conditions as above. On the other hand, the adsorbed microplastics become concentrators of other pollutants found in the environment. The sensitive differential-pulse voltammetry determination of bisphenol A (linear range 0.80-15.00 µM; detection limit 0.24 µM) was used together with a simple separation procedure for studying the adsorption of bisphenol A on polystyrene microparticles. The adsorption capacity (mg of bisphenol A retained per g of the polystyrene microplastics) decreased from approximately 5.7 to 0.8 mg g-1 with increasing dosages of polystyrene microparticles from 0.2 to 1.6 g l-1. The adsorption isotherms were modeled resulting in a monolayer of bisphenol A adsorbed on the microplastics (i.e., best fitted to a Langmuir model).

4.
J Clin Ultrasound ; 51(7): 1188-1197, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37318272

RESUMO

PURPOSE: We aimed to compare the diagnostic performance of magnetic resonance imaging (MRI) and transvaginal ultrasound (TVS) for detecting myometrial invasion (MI) in patients with low-grade endometrioid endometrial carcinoma. METHODS: A comprehensive search of MEDLINE (Pubmed), Web of Science, Embase and Scopus (from January 1990 to December 2022) was performed for articles comparing TVS and MRI in the evaluation of myometrial infiltration in low-grade (grade 1 or 2) endometrioid endometrial carcinoma in the same group of patients. We used QUADAS-2 tool for assessing the risk of bias of studies. RESULTS: We found 104 citations in our extensive research. Four articles were ultimately included in the meta-analysis, after excluding 100 reports. All articles were considered low risk of bias in most of the domains assessed in QUADAS-2. We observed that pooled sensitivity and specificity for detecting deep MI were 65% (95% confidence interval [CI] = 54%-75%) and 85% (95% CI = 79%-89%) for MRI, and 71% (95% CI = 63%-78%) and 76% (95% CI = 67%-83%) for TVS, respectively. No statistical differences were found between both imaging techniques (p > 0.05). We observed low heterogeneity for sensitivity and high for specificity regarding TVS; and moderate for both sensitivity and specificity in case of MRI. CONCLUSIONS: The diagnostic performance of TVS and MRI for the evaluation of deep MI in women with low-grade endometrioid endometrial cancer is similar. However, further research is needed as the number of studies is scanty.


Assuntos
Neoplasias do Endométrio , Humanos , Feminino , Neoplasias do Endométrio/diagnóstico por imagem , Invasividade Neoplásica/patologia , Ultrassonografia/métodos , Imageamento por Ressonância Magnética/métodos , Sensibilidade e Especificidade , Miométrio/diagnóstico por imagem , Miométrio/patologia , Miométrio/cirurgia , Estadiamento de Neoplasias
5.
Int J Mol Sci ; 24(20)2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37895040

RESUMO

Grapevine development and ripening are complex processes that involve several biochemical pathways, including fatty acid and lipid metabolism. Fatty acids are essential components of lipids, which play crucial roles in fruit maturation and flavor development. However, the dynamics of fatty acid metabolism in grape flowers and berries are poorly understood. In this study, we present those dynamics and investigate the mechanisms of fatty acid homeostasis on 'Thompson Seedless' berries using metabolomic and proteomic analyses. Low-polar metabolite profiling indicated a higher abundance of fatty acids at the pre-flowering and pre-veraison stages. Proteomic analyses revealed that grape flowers and berries display unique profiles of proteins involved in fatty acid biosynthesis, triacylglycerol assembly, fatty acid ß-oxidation, and lipid signaling. These findings show, for the first time, that fatty acid metabolism also plays an important role in the development of non-oil-rich tissues, opening new perspectives about lipid function and its relation to berry quality.


Assuntos
Vitis , Vitis/metabolismo , Frutas/metabolismo , Proteômica , Metabolismo dos Lipídeos , Ácidos Graxos/metabolismo , Lipídeos , Regulação da Expressão Gênica de Plantas
6.
Chem Biodivers ; 19(2): e202100807, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35043548

RESUMO

Cinnamtannin B-1 (C-B1) is a commercially-available trimeric A-type procyanidin with remarkable cellular actions mainly derived from its high radical scavenging activity. C-B1 is the main phenolic compound of laurel wood, which has previously been isolated by a combination of conventional chromatographic techniques. The first aim of this work was to find laurel trees containing as much C-B1 as possible, and learn about the influence of variables, such as gender and harvest time, on the production of C-B1 by the tree. It was found that all studied trees tend to give higher C-B1 percentages in the May-July period, from 6 % to 18 %, and lower ones around March (spring) and November (fall), from 1 % to 8 %. In a general way, it also seems that the female trees tend to produce a bit more C-B1 (from 2.8 % to 17.3 %) than male ones (from 1.7 % to 13.4 %). In addition, eight minor phenolic compounds [(-)-ent-catechin (1), (-)-ent-epicatechin-(4α→8)-ent-epicatechin (2), (epi)catechin-(4→8)-(epi)afzelechin-(4→8)-(epi)catechin (3), (+)-epiafzelechin-(4ß→8)-epicatechin (4), (-)-epicatechin (5), (-)-afzelechin-(4α→8)-epicatechin (6), (epi)afzelechin-(4→8)-(epi)afzelechin-(4→8)-(epi)catechin (7) and (+)-epicatechin-(4ß→8,2ß→O-7)-epicatechin-(4ß→8)-catechin (C-D1)] were found and quantified in the ethyl acetate extract of the wood samples. The second aim of this work was to improve the recovery of C-B1 from laurel wood. The use of the fast centrifugal partition chromatography (FCPC) technique has allowed for a recovery of 96 % of a technical-grade C-B1 (64 % in a previous protocol using conventional column chromatography on silica gel and size-exclusion chromatography).


Assuntos
Catequina , Laurus , Proantocianidinas , Catequina/química , Laurus/química , Proantocianidinas/química , Estações do Ano , Madeira/química
7.
Rev Med Chil ; 150(1): 125-130, 2022 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-35856975

RESUMO

We report a 50-year-old woman with a history of celiac disease, who presented with lumbar pain and progressive flaccid tetraparesis 48 hours after the inoculation of the first dose of CoronaVac inactivated SARS-CoV-2 vaccine. CSF was normal and electrodiagnostic studies showed an axonal motor polyneuropathy. No other triggers were identified, and other etiologies were ruled out. The presentation was compatible with the AMAN (Acute Motor Axonal Neuropathy) subtype of GBS, and intravenous immunoglobulin halted the progression of symptoms. Intensive neurorehabilitation was performed. The patient was discharged five weeks after admission, walking with poles and climbing stairs with minimal assistance. To date no cases of inactivated SARSCoV-2 vaccine related GBS have been reported. Thus, description of its clinical presentation is relevant. We discuss the current evidence relating GBS with vaccines, highlighting that vaccine associated GBS is a controversial entity and causality must be interpreted cautiously given the actual COVID-19 pandemic context.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Síndrome de Guillain-Barré , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Feminino , Síndrome de Guillain-Barré/induzido quimicamente , Síndrome de Guillain-Barré/epidemiologia , Humanos , Pessoa de Meia-Idade , Pandemias , SARS-CoV-2 , Vacinas
8.
Inorg Chem ; 60(4): 2783-2796, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33543934

RESUMO

Reactions of polyhydrides OsH6(PiPr3)2 (1) and IrH5(PiPr3)2 (2) with rollover cyclometalated hydride complexes have been investigated in order to explore the influence of a metal center on the MHn unit of the other in mixed valence binuclear polyhydrides. Hexahydride 1 activates an ortho-CH bond of the heterocyclic moiety of the trihydride metal-ligand compounds OsH3{κ2-C,N-[C5RH2N-py]}(PiPr3)2 (R = H (3), Me (4), Ph (5)). Reactions of 3 and 4 lead to the hexahydrides (PiPr3)2H3Os{µ-[κ2-C,N-[C5RH2N-C5H3N]-N,C-κ2]}OsH3(PiPr3)2 (R = H (6), Me (7)), whereas 5 gives the pentahydride (PiPr3)2H3Os{µ-[κ2-C,N-[C5H3N-C5(C6H4)H2N]-C,N,C-κ3]}OsH2(PiPr3)2 (8). Pentahydride 2 promotes C-H bond activation of 3 and the iridium-dihydride IrH2{κ2-C,N-[C5H3N-py]}(PiPr3)2 (9) to afford the heterobinuclear pentahydride (PiPr3)2H3Os{µ-[κ2-C,N-[C5H3N-C5H3N]-N,C-κ2]}IrH2(PiPr3)2 (10) and the homobinuclear tetrahydride (PiPr3)2H2Ir{µ-[κ2-C,N-[C5H3N-C5H3N]-N,C-κ2]}IrH2(PiPr3)2 (11), respectively. Complexes 6-8 and 11 display HOMO delocalization throughout the metal-heterocycle-metal skeleton. Their sequential oxidation generates mono- and diradicals, which exhibit intervalence charge transfer transitions. This notable ability allows the tuning of the strength of the hydrogen-hydrogen and metal-hydrogen interactions within the MHn units.

9.
Mikrochim Acta ; 188(1): 12, 2021 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-33389212

RESUMO

Silver nanoparticles (AgNPs) are widely used in industrial and consumer products owing to its antimicrobial nature and multiple applications. Consequently, their release into the environment is becoming a big concern because of their negative impacts on living organisms. In this work, AgNPs were detected at a potential of + 0.70 V vs. Ag/AgCl reference electrode, characterized, and quantified in consumer products by particle collision coulometry (PCC). The electrochemical results were compared with those measured with electron microscopy and single-particle inductively coupled plasma mass spectrometry. The theoretical and practical peculiarities of the application of PCC technique in the characterization of AgNPs were studied. Reproducible size distributions of the AgNPs were measured in a range 10-100 nm diameters. A power allometric function model was found between the frequency of the AgNPs collisions onto the electrode surface and the number concentration of nanoparticles up to a silver concentration of 1010 L-1 (ca. 25 ng L-1 for 10 nm AgNPs). A linear relationship between the number of collisions and the number concentration of silver nanoparticles was observed up to 5 × 107 L-1. The PCC method was applied to the quantification and size determination of the AgNPs in three-silver containing consumer products (a natural antibiotic and two food supplements). The mean of the size distributions (of the order 10-20 nm diameters) agrees with those measured by electron microscopy. The areas of current spikes from the chronoamperogram allow the rapid calculation of size distributions of AgNPs that impact onto the working electrode.

10.
Mikrochim Acta ; 187(3): 183, 2020 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-32088789

RESUMO

New electrochemical sensors are described for the rapid quantification of silver nanoparticles (AgNPs). They are based on the immobilization of L-cysteine on a glassy carbon electrode (GCE) and on the formation of electropolymerized oligomers on the GCE. Ligands with amino, sulfur and carboxy functional groups are used that are capable of selectively retaining AgNPs. The experimental conditions for electropolymerizations were optimized for each of four monomers studied: L-lysine, thiophene-3-carboxamide, thionin, and o-phenylene-diamine. The best retention capabilities and conditions for quantification of AgNPs were found for immobilized nanoparticle voltammetry. This method is more sensitive than others based on the sorption of AgNPs from dispersions. These ligands also retain ionic silver species. Hence, Ag(I) and Ag0 can be discriminated, and the total silver content can be quantified by stripping voltammetry. The best analytical properties (for dispersions of AgNPs of 40 nm diameter) were found with GCEs carrying electropolymerized L-lysine. Figures of merit include (a) sensitivity of 4.329 ± 0.031 µA µg-1 mL cm-2, (b) a detection limit of 0.010 µg mL-1, and (c) a relative standars deviation of about 7.2% (for n = 4). The poly-L-lysine sensors can also evaluate the size of the AgNPs in the range 20 to 80 nm diameter, owing to displacements of the maximum potential of the voltammetry peaks. Graphical abstractSchematic representation of the quantification of silver nanoparticles (AgNPs) with a glassy-carbon electrode (GCE) modified with electropolymerized poly(L-lysine). AgNPs (and Ag+ ions) are selectively preconcentrated in the polymer and determined by differential-pulse stripping voltammetry.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Prata/química , Eletrodos , Humanos
11.
J Sports Sci ; 36(22): 2531-2536, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29688149

RESUMO

Maximal oxygen uptake ([Formula: see text] max) is a key indicator to assess health as well as sports performance. Currently, maximal exercise testing is the most accurate measure of maximal aerobic power, since submaximal approaches are still imprecise. In this paper, we propose a new method to predict [Formula: see text] max from a submaximal, low intensity, test in sports men and women. 182 males and 108 females from the High Performance Center of Pontevedra (Spain), aged 10-46 years old, with a [Formula: see text] max between 30.1 and 81.2 mL·min-1·kg-1, completed a maximal incremental test to volitional exhaustion. The test began at a speed of 6 km·h-1 and increased by 0.25 km·h-1 every 15 seconds. Using the data gathered during the first 6 minutes of the test, two different regression models were adjusted using functional data analysis and a traditional linear regression model with scalar covariates. The functional regression model obtained the best results, adjusted r2 = 0.845 and RMSE = 2.8 mL·min-1·kg-1, but the linear regression model also obtained a good fit, adjusted r2 = 0.798 and RMSE = 3.5 mL·min-1·kg-1. Both methods are more accurate than classical submaximal tests, although oxygen consumption needs to be measured during the test.


Assuntos
Teste de Esforço/métodos , Consumo de Oxigênio , Corrida/fisiologia , Adolescente , Adulto , Desempenho Atlético/fisiologia , Criança , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Troca Gasosa Pulmonar , Análise de Regressão , Adulto Jovem
12.
Cereb Cortex ; 26(7): 3010-22, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26045565

RESUMO

The emergence of conscious visual perception is assumed to ignite late (∼250 ms) gamma-band oscillations shortly after an initial (∼100 ms) forward sweep of neural sensory (nonconscious) information. However, this neural evidence is not utterly congruent with rich behavioral data which rather point to piecemeal (i.e., graded) perceptual processing. To address the unexplored neural mechanisms of piecemeal ignition of conscious perception, hierarchical script sensitivity of the putative visual word form area (VWFA) was exploited to signal null (i.e., sensory), partial (i.e., letter-level), and full (i.e., word-level) conscious perception. Two magnetoencephalography experiments were conducted in which healthy human participants viewed masked words (Experiment I: active task, Dutch words; Experiment II: passive task, Hebrew words) while high-frequency (broadband gamma) brain activity was measured. Findings revealed that piecemeal conscious perception did not ignite a linear piecemeal increase in oscillations. Instead, whereas late (∼250 ms) gamma-band oscillations signaled full conscious perception (i.e., word-level), partial conscious perception (i.e., letter-level) was signaled via the inhibition of the early (∼100 ms) forward sweep. This inhibition regulates the downstream broadcast to filter out irrelevant (i.e., masks) information. The findings thus highlight a local (VWFA) gatekeeping mechanism for conscious perception, operating by filtering out and in selective percepts.


Assuntos
Encéfalo/fisiologia , Estado de Consciência/fisiologia , Ritmo Gama/fisiologia , Leitura , Percepção Visual/fisiologia , Feminino , Humanos , Modelos Lineares , Magnetoencefalografia , Masculino , Testes Neuropsicológicos , Processamento de Sinais Assistido por Computador , Adulto Jovem
13.
Epilepsy Behav ; 53: 140-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26575255

RESUMO

Temporal lobe epilepsy can induce functional plasticity in temporoparietal networks involved in language and long-term memory processing. Previous studies in healthy subjects have revealed the relative difficulty for this network to respond effectively across different experimental designs, as compared to more reactive regions such as frontal lobes. For a protocol to be optimal for clinical use, it has to first show robust effects in a healthy cohort. In this study, we developed a novel experimental paradigm entitled NEREC, which is able to reveal the robust participation of temporoparietal networks in a uniquely combined language and memory task, validated in an fMRI study with healthy subjects. Concretely, NEREC is composed of two runs: (a) an intermixed language-memory task (confrontation naming associated with encoding in nonverbal items, NE) to map language (i.e., word retrieval and lexico-semantic processes) combined with simultaneous long-term verbal memory encoding (NE items named but also explicitly memorized) and (b) a memory retrieval task of items encoded during NE (word recognition, REC) intermixed with new items. Word recognition is based on both perceptual-semantic familiarity (feeling of 'know') and accessing stored memory representations (remembering). In order to maximize the remembering and recruitment of medial temporal lobe structures, we increased REC difficulty by changing the modality of stimulus presentation (from nonverbal during NE to verbal during REC). We report that (a) temporoparietal activation during NE was attributable to both lexico-semantic (language) and memory (episodic encoding and semantic retrieval) processes; that (b) encoding activated the left hippocampus, bilateral fusiform, and bilateral inferior temporal gyri; and that (c) task recognition (recollection) activated the right hippocampus and bilateral but predominant left fusiform gyrus. The novelty of this protocol consists of (a) combining two tasks in one (language and long-term memory encoding/recall) instead of applying isolated tasks to map temporoparietal regions, (b) analyzing NE data based on performances recorded during REC, (c) double-mapping networks involved in naming and in long-term memory encoding and retrieval, (d) focusing on remembering with hippocampal activation and familiarity judgment with lateral temporal cortices activation, and (e) short duration of examination and feasibility. These aspects are of particular interest in patients with TLE, who frequently show impairment of these cognitive functions. Here, we show that the novel protocol is suited for this clinical evaluation.


Assuntos
Mapeamento Encefálico/métodos , Hipocampo/fisiologia , Idioma , Imageamento por Ressonância Magnética/métodos , Memória de Longo Prazo/fisiologia , Lobo Temporal/fisiologia , Adulto , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Reconhecimento Psicológico/fisiologia , Adulto Jovem
14.
J Neurosci ; 33(24): 10123-31, 2013 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-23761907

RESUMO

Many high-level visual regions exhibit complex patterns of stimulus selectivity that make their responses difficult to explain in terms of a single cognitive mechanism. For example, the parahippocampal place area (PPA) responds maximally to environmental scenes during fMRI studies but also responds strongly to nonscene landmark objects, such as buildings, which have a quite different geometric structure. We hypothesized that PPA responses to scenes and buildings might be driven by different underlying mechanisms with different temporal profiles. To test this, we examined broadband γ (50-150 Hz) responses from human intracerebral electroencephalography recordings, a measure that is closely related to population spiking activity. We found that the PPA distinguished scene from nonscene stimuli in ∼80 ms, suggesting the operation of a bottom-up process that encodes scene-specific visual or geometric features. In contrast, the differential PPA response to buildings versus nonbuildings occurred later (∼170 ms) and may reflect a delayed processing of spatial or semantic features definable for both scenes and objects, perhaps incorporating signals from other cortical regions. Although the response preferences of high-level visual regions are usually interpreted in terms of the operation of a single cognitive mechanism, these results suggest that a more complex picture emerges when the dynamics of recognition are considered.


Assuntos
Mapeamento Encefálico , Potenciais Evocados Visuais/fisiologia , Giro Para-Hipocampal/fisiopatologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Eletrodos Implantados , Eletroencefalografia , Epilepsia/patologia , Epilepsia/fisiopatologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Fatores de Tempo , Adulto Jovem
15.
Neuroimage ; 95: 276-86, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24650595

RESUMO

Eye movements are a constant and essential component of natural vision, yet, most of our knowledge about the human visual system comes from experiments that restrict them. This experimental constraint is mostly in place to control visual stimuli presentation and to avoid artifacts in non-invasive measures of brain activity, however, this limitation can be overcome with intracranial EEG (iEEG) recorded from epilepsy patients. Moreover, the high-frequency components of the iEEG signal (between about 50 and 150Hz) can provide a proxy of population-level spiking activity in any cortical area during free-viewing. We combined iEEG with high precision eye-tracking to study fine temporal dynamics and functional specificity in the fusiform face (FFA) and visual word form area (VWFA) while patients inspected natural pictures containing faces and text. We defined the first local measure of visual (electrophysiological) responsiveness adapted to free-viewing in humans: amplitude modulations in the high-frequency activity range (50-150Hz) following fixations (fixation-related high-frequency response). We showed that despite the large size of receptive fields in the ventral occipito-temporal cortex, neural activity during natural vision of realistic cluttered scenes is mostly dependent upon the category of the foveated stimulus - suggesting that category-specificity is preserved during free-viewing and that attention mechanisms might filter out the influence of objects surrounding the fovea.


Assuntos
Movimentos Oculares/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Processamento de Sinais Assistido por Computador
16.
Neuroimage ; 95: 129-35, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24667455

RESUMO

Stimulus repetition can produce neural response attenuation in stimulus-category selective networks within the occipito-temporal lobe. It is hypothesized that this neural suppression reflects the functional sharpening of local neuronal assemblies which boosts information processing efficiency. This neural suppression phenomenon has been mainly reported during conditions of conscious stimulus perception. The question remains whether frequent stimuli processed in the absence of conscious perception also induce repetition suppression in those specialized networks. Using rare intracranial EEG recordings in the ventral occipito-temporal cortex (VOTC) of human epileptic patients we investigated neural repetition suppression in conditions of conscious and unconscious visual processing of words. To this end, we used an orthogonal design manipulating respectively stimulus repetition (frequent vs. unique stimuli) and conscious perception (masked vs. unmasked stimuli). By measuring the temporal dynamics of high-frequency broadband gamma activity in VOTC and testing for main and interaction effects, we report that early processing of words in word-form selective networks exhibits a temporal cascade of modulations by stimulus repetition and masking: neuronal attenuation initially is observed in response to repeated words (irrespective of consciousness), that is followed by a second modulation contingent upon word reportability (irrespective of stimulus repetition). Later on (>300ms post-stimulus), a significant effect of conscious perception on the extent of repetition suppression was observed. The temporal dynamics of consciousness, the recognition memory processes and their interaction revealed in this study advance our understanding of their contributions to the neural mechanisms of word processing in VOTC.


Assuntos
Córtex Cerebral/fisiologia , Estado de Consciência/fisiologia , Inibição Neural/fisiologia , Percepção Visual/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Processamento de Sinais Assistido por Computador , Inconsciência , Adulto Jovem
17.
Epilepsy Behav Rep ; 27: 100691, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39050405

RESUMO

We report on the case of an adolescent with juvenile myoclonic epilepsy exhibiting compulsory sporadic voluntary movement. These movements entailed the deliberate act of touching her forehead with her hand and were triggered by a short and indefinable cephalic sensation. Upon inquiry regarding the nature of this movement, the patient reported a sudden perception of a peculiar event localized "inside her head". In the course of a prolonged video-electroencephalographic recording, it appeared that the movements consistently followed the occurrence of diffuse Generalized Spike-and-Wave Bursts (GSWBs), lasting one to three seconds. This observation suggests that the impact of the GSWBs on the patient's stream of consciousness could be detected by the patient herself, who attributed it to an internal sensation, like a "blip on a screen". This clinical observation echoes the "blip syndrome", as described by the neurologist James W. Lance thirty years ago. These findings give some support that "blips" could be of an epileptic origin and lend weight to the notion that some patients could perceive their own EEG discharges. Moreover, this observation should be added to the perennial debate on the cognitive impact of intercritical discharges.

18.
Front Public Health ; 12: 1380922, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38745999

RESUMO

Background: Age-friendly environments intend to promote active ageing by facilitating social, mental, and physical participation. This could potentially delay the onset of chronic complex conditions, enabling people to live longer independently at home, and prevent loneliness. This study investigates a community-based living environment in Norway called Helgetun and aims to explore how it can facilitate active ageing. Method: We chose an ethnographic approach consisting of observation, informal conversations, and in-depth semi-structured interviews with 15 residents (11 female, 4 male, ages 62-84). We analysed the data using reflexive thematic analysis. Result: We developed three themes on facilitating active ageing in this living environment: maintaining self-identity, experiencing growth and development, and feeling a sense of belonging. These themes were related to physical activity levels, social engagement, and overall satisfaction with the living environment. Maintaining self-identity concerned getting a new role in life as well as access to meaningful activities. Experiencing growth and development involved being exposed to new activities, learning new skills, and experiencing mastery. Lastly, feeling a sense of belonging meant feeling safe and part of a group, as well as receiving social support and help. This feeling of social connectedness and safety was reflected in their experience with the COVID-19 pandemic, in which most felt relatively unaffected, suggesting that this way of living could increase reliance among this age group. Conclusion: Having a flexible structure, adapting to the core needs and individual resources of the residents, can facilitate active ageing in community-based living environments. Our findings contribute to the growing evidence that these environments increase social and physical engagement, whilst reducing social isolation and loneliness. These findings may be particularly relevant in a Norwegian context-where older adults are less dependent on family for care-and are meant as grounding points for policymakers to reflect upon designing future senior living.


Assuntos
Antropologia Cultural , COVID-19 , Vida Independente , Humanos , Noruega , Masculino , Feminino , Idoso , Idoso de 80 Anos ou mais , Pessoa de Meia-Idade , COVID-19/psicologia , Envelhecimento/psicologia , Exercício Físico/psicologia , Apoio Social , Solidão/psicologia , Pesquisa Qualitativa , Entrevistas como Assunto
19.
Eur J Obstet Gynecol Reprod Biol ; 292: 194-200, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38042117

RESUMO

In this review, we aimed to assess the diagnostic performance of ultrasound for assessing the tumor spread in the abdomen in women with ovarian cancer. A search for studies evaluating the role of ultrasound for assessing intrabdominal tumor spread in women with ovarian cancer compared to surgery from January 2011 to March 2023 was performed in PubMed/MEDLINE, Web of Science, and Scopus databases. The Quality Assessment of Diagnostic Accuracy Studies 2 evaluated the quality of the studies (QUADAS-2). All analyses were performed using MIDAS and METANDI commands in STATA 12.0 software. We identified 1552 citations. After exclusions, five studies comprising 822 women were included. Quality of studies were considered as good, except for patient selection as all studies were considered as having high risk of bias. The pooled sensitivity and specificity could be calculated for three anatomical areas (recto-sigma, major omentum and root of mesentery) and the presence of ascites. The pooled sensitivity and specificity for detecting disease in the recto-sigma, major omentum and root of mesentery were 0.83 and 0.95, 0.87 and 0.87, and 0.29 and 0.99, respectively. The pooled sensitivity and specificity for detecting ascites was 0.95 and 0.91, respectively. There is evidence that ultrasound offers good diagnostic performance for evaluating the intra-abdominal extent of disease in women with suspected ovarian cancer.


Assuntos
Ascite , Neoplasias Ovarianas , Feminino , Humanos , Neoplasias Ovarianas/patologia , Ultrassonografia , Sensibilidade e Especificidade
20.
J Agric Food Chem ; 72(23): 13023-13038, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38809962

RESUMO

Extra virgin olive oil (EVOO), a staple of the Mediterranean diet, is rich in phenolic compounds recognized for their potent bioactive effects, including anticancer and anti-inflammatory properties. However, its effects on vascular health remain relatively unexplored. In this study, we examined the impact of a "picual" EVOO extract from Jaén, Spain, on endothelial cells. Proteomic analysis revealed the modulation of angiogenesis-related processes. In subsequent in vitro experiments, the EVOO extract inhibited endothelial cell migration, adhesion, invasion, ECM degradation, and tube formation while inducing apoptosis. These results provide robust evidence of the extract's antiangiogenic potential. Our findings highlight the potential of EVOO extracts in mitigating angiogenesis-related pathologies, such as cancer, macular degeneration, and diabetic retinopathy.


Assuntos
Inibidores da Angiogênese , Movimento Celular , Azeite de Oliva , Extratos Vegetais , Proteômica , Azeite de Oliva/química , Humanos , Inibidores da Angiogênese/farmacologia , Inibidores da Angiogênese/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Movimento Celular/efeitos dos fármacos , Olea/química , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Apoptose/efeitos dos fármacos , Espanha , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa