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1.
Brain ; 147(7): 2483-2495, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38701342

RESUMEN

Network neuroscience offers a unique framework to understand the organizational principles of the human brain. Despite recent progress, our understanding of how the brain is modulated by focal lesions remains incomplete. Resection of the temporal lobe is the most effective treatment to control seizures in pharmaco-resistant temporal lobe epilepsy (TLE), making this syndrome a powerful model to study lesional effects on network organization in young and middle-aged adults. Here, we assessed the downstream consequences of a focal lesion and its surgical resection on the brain's structural connectome, and explored how this reorganization relates to clinical variables at the individual patient level. We included adults with pharmaco-resistant TLE (n = 37) who underwent anterior temporal lobectomy between two imaging time points, as well as age- and sex-matched healthy controls who underwent comparable imaging (n = 31). Core to our analysis was the projection of high-dimensional structural connectome data-derived from diffusion MRI tractography from each subject-into lower-dimensional gradients. We then compared connectome gradients in patients relative to controls before surgery, tracked surgically-induced connectome reconfiguration from pre- to postoperative time points, and examined associations to patient-specific clinical and imaging phenotypes. Before surgery, individuals with TLE presented with marked connectome changes in bilateral temporo-parietal regions, reflecting an increased segregation of the ipsilateral anterior temporal lobe from the rest of the brain. Surgery-induced connectome reorganization was localized to this temporo-parietal subnetwork, but primarily involved postoperative integration of contralateral regions with the rest of the brain. Using a partial least-squares analysis, we uncovered a latent clinical imaging signature underlying this pre- to postoperative connectome reorganization, showing that patients who displayed postoperative integration in bilateral fronto-occipital cortices also had greater preoperative ipsilateral hippocampal atrophy, lower seizure frequency and secondarily generalized seizures. Our results bridge the effects of focal brain lesions and their surgical resections with large-scale network reorganization and interindividual clinical variability, thus offering new avenues to examine the fundamental malleability of the human brain.


Asunto(s)
Lobectomía Temporal Anterior , Conectoma , Epilepsia del Lóbulo Temporal , Lóbulo Temporal , Humanos , Femenino , Masculino , Adulto , Epilepsia del Lóbulo Temporal/cirugía , Epilepsia del Lóbulo Temporal/fisiopatología , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Epilepsia del Lóbulo Temporal/patología , Lóbulo Temporal/patología , Lóbulo Temporal/cirugía , Lóbulo Temporal/diagnóstico por imagen , Lobectomía Temporal Anterior/métodos , Persona de Mediana Edad , Adulto Joven , Imagen de Difusión Tensora , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/patología , Epilepsia Refractaria/cirugía , Epilepsia Refractaria/diagnóstico por imagen , Epilepsia Refractaria/fisiopatología , Epilepsia Refractaria/patología
2.
Chem Soc Rev ; 53(3): 1514-1551, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38167899

RESUMEN

Protein-based bioactive coatings have emerged as a versatile and promising strategy for enhancing the performance and biocompatibility of diverse biomedical materials and devices. Through surface modification, these coatings confer novel biofunctional attributes, rendering the material highly bioactive. Their widespread adoption across various domains in recent years underscores their importance. This review systematically elucidates the behavior of protein-based bioactive coatings in organisms and expounds on their underlying mechanisms. Furthermore, it highlights notable advancements in artificial synthesis methodologies and their functional applications in vitro. A focal point is the delineation of assembly strategies employed in crafting protein-based bioactive coatings, which provides a guide for their expansion and sustained implementation. Finally, the current trends, challenges, and future directions of protein-based bioactive coatings are discussed.


Asunto(s)
Materiales Biocompatibles Revestidos
3.
Epilepsy Behav ; 140: 109100, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36791632

RESUMEN

OBJECTIVE: We aimed to determine whether alterations in spontaneous regional brain activity in those with generalized tonic-clonic seizures (GTCS) and focal to bilateral tonic-clonic seizures (FBTCS) and explore whether the alterations could be used as biomarkers to classify disease subtypes through support vector machine analysis (SVM). METHODS: The fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) from resting-state functional magnetic resonance imaging (rs-fMRI) data were extracted from 57 patients with GTCS, 35 patients with FBTCS, and 50 age-matched and sex-matched normal controls (NCs) using the DPARSF 5.0 toolbox. Between-group comparisons were adjusted for covariates (age, sex, and equipment). Correlation analyses between imaging biomarkers and the frequency or duration of seizure activity were calculated using partial correlations. The differential imaging indicators, age, and sex were considered as the discriminative features in the SVM to evaluate classification performance. RESULTS: The patients with GTCS showed lower fALFF values (voxel p < 0.001, cluster p < 0.05, Gaussian random field corrected, GRF corrected) in the right postcentral gyrus and precentral gyrus and lower ReHo values (GRF corrected) in the middle temporal gyrus than the NCs. The patients with FBTCS showed higher fALFF (GRF corrected) values in the right postcentral and precentral gyrus and higher ReHo (GRF corrected) values in the right postcentral gyrus. Both fALFF (GRF corrected) and ReHo (GRF corrected) values were lower in the right postcentral gyrus and precentral gyrus in the GTCS group than in the FBTCS group. In patients with FBTCS, fALFF values in the right postcentral and precentral gyrus were positively correlated with duration (r = 0.655, p = 0.008, Bonferroni corrected) in the low-duration group, and ReHo values in the right postcentral gyrus were positively correlated with frequency (r = 0.486, p = 0.022, uncorrected) in the low-frequency group. SVM results showed receiver operating characteristic curves of 0.89, 0.87, and 0.76 for the classification between GTCS and NC, between FBTCS and NC, and GTCS and FBTCS, respectively. SIGNIFICANCE: This study detected alterations in fALFF and ReHo in the postcentral gyrus and precentral gyrus in patients with GTCS and FBTCS, which might contribute to understanding the pathogenesis, disease classification, and clinical targeted therapy.


Asunto(s)
Encéfalo , Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Convulsiones/tratamiento farmacológico , Mapeo Encefálico , Lóbulo Temporal
4.
Hum Brain Mapp ; 42(12): 3950-3962, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-33978292

RESUMEN

The structural covariance network (SCN) has provided a perspective on the large-scale brain organization impairment in the Alzheimer's Disease (AD) continuum. However, the successive structural impairment across brain regions, which may underlie the disrupted SCN in the AD continuum, is not well understood. In the current study, we enrolled 446 subjects with AD, mild cognitive impairment (MCI) or normal aging (NA) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. The SCN as well as a casual SCN (CaSCN) based on Granger causality analysis were applied to the T1-weighted structural magnetic resonance images of the subjects. Compared with that of the NAs, the SCN was disrupted in the MCI and AD subjects, with the hippocampus and left middle temporal lobe being the most impaired nodes, which is in line with previous studies. In contrast, according to the 194 subjects with records on CSF amyloid and Tau, the CaSCN revealed that during AD progression, the CaSCN was enhanced. Specifically, the hippocampus, thalamus, and precuneus/posterior cingulate cortex (PCC) were identified as the core regions in which atrophy originated and could predict atrophy in other brain regions. Taken together, these findings provide a comprehensive view of brain atrophy in the AD continuum and the relationships among the brain atrophy in different regions, which may provide novel insight into the progression of AD.


Asunto(s)
Envejecimiento/patología , Enfermedad de Alzheimer/patología , Corteza Cerebral/patología , Disfunción Cognitiva/patología , Progresión de la Enfermedad , Tálamo/patología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico por imagen , Atrofia/patología , Corteza Cerebral/diagnóstico por imagen , Disfunción Cognitiva/diagnóstico por imagen , Femenino , Hipocampo/diagnóstico por imagen , Hipocampo/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Tálamo/diagnóstico por imagen
5.
Epilepsia ; 61(6): 1221-1233, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32452574

RESUMEN

OBJECTIVE: Temporal lobe epilepsy (TLE) is the most common drug-resistant epilepsy in adults. Although it is commonly related to hippocampal pathology, increasing evidence suggests structural changes beyond the mesiotemporal lobe. Functional anomalies and their link to underlying structural alterations, however, remain incompletely understood. METHODS: We studied 30 drug-resistant TLE patients and 57 healthy controls using multimodal magnetic resonance imaging (MRI) analyses. All patients had histologically verified hippocampal sclerosis and underwent postoperative imaging to outline the extent of their surgical resection. Our analysis leveraged a novel resting-state functional MRI framework that parameterizes functional connectivity distance, consolidating topological and physical properties of macroscale brain networks. Functional findings were integrated with morphological and microstructural metrics, and utility for surgical outcome prediction was assessed using machine learning techniques. RESULTS: Compared to controls, TLE patients showed connectivity distance reductions in temporoinsular and prefrontal networks, indicating topological segregation of functional networks. Testing for morphological and microstructural associations, we observed that functional connectivity contractions occurred independently from TLE-related cortical atrophy but were mediated by microstructural changes in the underlying white matter. Following our imaging study, all patients underwent an anterior temporal lobectomy as a treatment of their seizures, and postsurgical seizure outcome was determined at a follow-up at least 1 year after surgery. Using a regularized supervised machine learning paradigm with fivefold cross-validation, we demonstrated that patient-specific functional anomalies predicted postsurgical seizure outcome with 76 ± 4% accuracy, outperforming classifiers operating on clinical and structural imaging features. SIGNIFICANCE: Our findings suggest connectivity distance contractions as a macroscale substrate of TLE. Functional topological isolation may represent a microstructurally mediated network mechanism that tilts the balance toward epileptogenesis in affected networks and that may assist in patient-specific surgical prognostication.


Asunto(s)
Conectoma/métodos , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Epilepsia del Lóbulo Temporal/cirugía , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiopatología , Adolescente , Adulto , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Encéfalo/cirugía , Epilepsia del Lóbulo Temporal/fisiopatología , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Red Nerviosa/cirugía , Valor Predictivo de las Pruebas , Resultado del Tratamiento , Adulto Joven
6.
Hum Brain Mapp ; 36(7): 2756-66, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25879781

RESUMEN

Amplitude and functional connectivity are two fundamental parameters for describing the spontaneous brain fluctuations. These two parameters present close coupling in physiological state, and present different alteration patterns in epilepsy revealed by functional MRI (fMRI). We hypothesized that the alteration of coupling between these two imaging parameters may be underpinned by specific pathological factors of epilepsy, and can be employed to improve the capability for epileptic focus detection. Forty-seven patients (26 left- and 21 right-sided) with mesial temporal lobe epilepsy (mTLE) and 32 healthy controls underwent resting-state fMRI scans. All patients were detected to have interictal epileptic discharges on simultaneous electroencephalograph (EEG) recordings. Amplitude-connectivity coupling was calculated by correlating amplitude and functional connectivity density of low-frequency brain fluctuations. We observed reduced amplitude-connectivity coupling associated with epileptic discharges in the mesial temporal regions in both groups of patients, and increased coupling associated with epilepsy durations in the posterior regions of the default-mode network in the right-sided patients. Moreover, we proposed a new index of amplitude subtracting connectivity, which elevated imaging contrast for differentiating the patients from the controls. The findings indicated that epileptic discharges and chronic damaging effect of epilepsy might both contribute to alterations of amplitude-connectivity coupling in different pivotal regions in mTLE. Investigation on imaging coupling provides synergistic approach for describing brain functional changing features in epilepsy.


Asunto(s)
Electroencefalografía/métodos , Epilepsia del Lóbulo Temporal/fisiopatología , Imagen por Resonancia Magnética/métodos , Adulto , Conectoma , Femenino , Humanos , Masculino
7.
BMC Neurosci ; 15: 117, 2014 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-25413842

RESUMEN

BACKGROUND: The roles of iron in epilepsy and its pathophysiological significance are poorly understood, especially whether iron levels are abnormal in subcortcal structures. This study aims to demonstrate whole-brain iron alterations and its clinical relevancies in mesial temporal lobe epilepsy (mTLE) in vivo, using susceptibility-weighted magnetic resonance imaging (SWI). METHODS: We studied 62 patients with mTLE and 62 healthy controls. Brain iron concentration was quantified using SWI phase values. Voxel-wise analysis was carried out to compare iron levels between mTLE and controls, and to assess the relationship between altered iron concentration and clinical parameters in mTLE. RESULTS: Patients with mTLE showed decreases of iron levels in the subcortical structures such as substantia nigra, red nucleus, and basal ganglia. Conversely, iron levels were decreased in the cortex. Subcortical iron levels were negatively correlated to those in the cortex. Moreover, cortical and basal ganglia iron levels were related to clinical variables including epilepsy duration, age at seizures onset, and histories of precipitating factors. CONCLUSIONS: Our SWI findings suggest a redistribution of iron between subcortical and cortical structures in mTLE. The degree of redistribution is affected by both progression of epilepsy and precipitating factors. Investigation on brain iron redistribution offers new insights into the pathogenesis of mTLE, and may be a potential biomarker for monitoring the clinical progression of epilepsy.


Asunto(s)
Encéfalo/metabolismo , Epilepsia del Lóbulo Temporal/metabolismo , Hierro/metabolismo , Adolescente , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
8.
Colloids Surf B Biointerfaces ; 225: 113239, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36889106

RESUMEN

Coatings with both anti-fouling and bactericidal functions are used in many fields. In this work, lysozyme (Lyso) and poly (2-Methylallyloxyethyl phosphorylcholine) (PMPC) conjugate (Lyso-PMPC) is successfully designed and synthesized for the first time. A new nanofilm (PTL-PMPC) is then obtained by phase transition of lysozyme via the reduction of disulfide bonds in Lyso-PMPC. Benefit from lysozyme amyloid-like aggregates as surface anchors, the nanofilm shows excellent stability, it remains unchanged after treatment under extreme conditions such as ultrasonic and 3 M tape peeling. Due to the presence of zwitterionic polymer (PMPC) brush, the PTL-PMPC film has excellent antifouling properties against cell, bacterium, fungi, proteins, biofluids, phosphatide, polyose, esters, and carbohydrates. Meanwhile, the PTL-PMPC film is colourless and transparent. Further, a new coating (PTL-PMPC/PHMB) is fabricated by hybridizing PTL-PMPC with poly (hexamethylene biguanide) (PHMB). This coating had excellent antibacterial properties, and the antibacterial rate against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is more than 99.99%. In addition, the coating exhibit good hemocompatibility and low cytotoxicity.


Asunto(s)
Incrustaciones Biológicas , Muramidasa , Muramidasa/farmacología , Incrustaciones Biológicas/prevención & control , Staphylococcus aureus , Escherichia coli , Antibacterianos/farmacología , Antibacterianos/química
9.
ACS Appl Mater Interfaces ; 15(8): 10426-10440, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36791143

RESUMEN

Polyetheretherketone (PEEK), a widely used implant material, has attracted the attention of scientific researchers because of its bone-matched elastic modulus, radiolucency, and chemical resistance. However, the bioinert chemical properties of PEEK do not promote bone apposition once implanted. In this study, using a phase-transitioned lysozyme (PTL) nanofilm as a sandwiched layer, a robust hydroxyapatite (HAp) coating on PEEK (HAp@PTL@PEEK) is constructed. The PTL nanofilm shows strong adhesion to the PEEK surface and induces biomimetic mineralization to form a compact HAp coating on PEEK in simulated body fluids. This HAp coating not only shares a higher adhesion strength and better stability but can also be applied to implants with complex 3D structures. HAp@PTL@PEEK showed significantly enhanced osteogenic capacity when cultured with rat bone marrow mesenchymal stem cells by promoting initial cell adhesion, proliferation, and osteogenic differentiation in vitro. In vivo evaluations utilizing models of femoral condyle defects and skull defects confirm that the HAp coating substantially augments bone remodeling and osseointegration ability. Compared with the traditional method, our modified method is simpler, more environmentally friendly, and uses less hazardous components. Furthermore, the obtained HAp coating shares a higher adhesion strength to PEEK and a better osteogenic capacity. The study offers a novel method to improve the osseointegration of PEEK-based implants in biointerfaces and tissue engineering.


Asunto(s)
Oseointegración , Osteogénesis , Ratas , Animales , Biomimética , Polímeros , Polietilenglicoles/química , Benzofenonas , Cetonas/química , Durapatita/química , Propiedades de Superficie
10.
Nat Neurosci ; 26(4): 542-554, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36941428

RESUMEN

Reactive astrocytes play an important role in neurological diseases, but their molecular and functional phenotypes in epilepsy are unclear. Here, we show that in patients with temporal lobe epilepsy (TLE) and mouse models of epilepsy, excessive lipid accumulation in astrocytes leads to the formation of lipid-accumulated reactive astrocytes (LARAs), a new reactive astrocyte subtype characterized by elevated APOE expression. Genetic knockout of APOE inhibited LARA formation and seizure activities in epileptic mice. Single-nucleus RNA sequencing in TLE patients confirmed the existence of a LARA subpopulation with a distinct molecular signature. Functional studies in epilepsy mouse models and human brain slices showed that LARAs promote neuronal hyperactivity and disease progression. Targeting LARAs by intervention with lipid transport and metabolism could thus provide new therapeutic options for drug-resistant TLE.


Asunto(s)
Epilepsia del Lóbulo Temporal , Epilepsia , Humanos , Ratones , Animales , Astrocitos/metabolismo , Progresión de la Enfermedad , Modelos Animales de Enfermedad , Lípidos , Apolipoproteínas E/metabolismo , Hipocampo/metabolismo
11.
Brain ; 134(Pt 10): 2912-28, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21975588

RESUMEN

The human brain is a large-scale integrated network in the functional and structural domain. Graph theoretical analysis provides a novel framework for analysing such complex networks. While previous neuroimaging studies have uncovered abnormalities in several specific brain networks in patients with idiopathic generalized epilepsy characterized by tonic-clonic seizures, little is known about changes in whole-brain functional and structural connectivity networks. Regarding functional and structural connectivity, networks are intimately related and share common small-world topological features. We predict that patients with idiopathic generalized epilepsy would exhibit a decoupling between functional and structural networks. In this study, 26 patients with idiopathic generalized epilepsy characterized by tonic-clonic seizures and 26 age- and sex-matched healthy controls were recruited. Resting-state functional magnetic resonance imaging signal correlations and diffusion tensor image tractography were used to generate functional and structural connectivity networks. Graph theoretical analysis revealed that the patients lost optimal topological organization in both functional and structural connectivity networks. Moreover, the patients showed significant increases in nodal topological characteristics in several cortical and subcortical regions, including mesial frontal cortex, putamen, thalamus and amygdala relative to controls, supporting the hypothesis that regions playing important roles in the pathogenesis of epilepsy may display abnormal hub properties in network analysis. Relative to controls, patients showed further decreases in nodal topological characteristics in areas of the default mode network, such as the posterior cingulate gyrus and inferior temporal gyrus. Most importantly, the degree of coupling between functional and structural connectivity networks was decreased, and exhibited a negative correlation with epilepsy duration in patients. Our findings suggest that the decoupling of functional and structural connectivity may reflect the progress of long-term impairment in idiopathic generalized epilepsy, and may be used as a potential biomarker to detect subtle brain abnormalities in epilepsy. Overall, our results demonstrate for the first time that idiopathic generalized epilepsy is reflected in a disrupted topological organization in large-scale brain functional and structural networks, thus providing valuable information for better understanding the pathophysiological mechanisms of generalized tonic-clonic seizures.


Asunto(s)
Encéfalo/fisiopatología , Epilepsia Generalizada/fisiopatología , Red Nerviosa/fisiopatología , Vías Nerviosas/fisiopatología , Convulsiones/fisiopatología , Adolescente , Adulto , Mapeo Encefálico , Imagen de Difusión Tensora , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética , Masculino , Neuronas/fisiología , Reproducibilidad de los Resultados
12.
RSC Adv ; 12(20): 12363-12370, 2022 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-35480381

RESUMEN

A sulfonated porous polymer monolith (PPM-SO3H) has been prepared via the polymerisation of styrene (St) and divinyl benzene (DVB) with organic microspheres as pore-forming agents, followed by sulfonation with concentrated sulfuric acid. It was characterized by acid-base titration in order to determine its acid density, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and thermogravimetric analysis (TG). The PPM-SO3H showed an acid density of 1.89 mmol g-1 and pore cavities with an average diameter of 870 nm. The catalytic activity of PPM-SO3H in practical biodiesel synthesis from waste fatty acids was investigated and the main reaction parameters were optimized through orthogonal experiment. The best reaction conditions obtained for the optimization of methanol to oil ratio, catalyst concentration, reaction temperature and reaction time were 1 : 1, 20%, 80 °C and 8 h, respectively. PPM-SO3H showed excellent catalytic activity. In biodiesel synthesis, the esterification rate of PPM-SO3H is 96.9%, which is much higher than that of commercial poly(sodium-p-styrenesulfonate) (esterification rate 29.0%). The PPM-SO3H can be reused several times without significant loss of catalytic activity; the esterification rate was still 90.8% after 6 cycles. The pore size of this porous polymer monolith can be controlled. The dimension and shape of this porous polymer monolith were also adjustable by choosing a suitable polymerisation container.

13.
J Clin Med ; 11(12)2022 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-35743511

RESUMEN

This study aimed to investigate the feasibility of predicting oxygen 6-methylguanine-DNA methyltransferase (MGMT) promoter methylation in diffuse gliomas by developing a deep learning approach using MRI radiomics. A total of 111 patients with diffuse gliomas participated in the retrospective study (56 patients with MGMT promoter methylation and 55 patients with MGMT promoter unmethylation). The radiomics features of the two regions of interest (ROI) (the whole tumor area and the tumor core area) for four sequences, including T1 weighted image (T1WI), T2 weighted image (T2WI), apparent diffusion coefficient (ADC) maps, and T1 contrast-enhanced (T1CE) MR images were extracted and jointly fed into the residual network. Then the deep learning method was developed and evaluated with a five-fold cross-validation, where in each fold, the dataset was randomly divided into training (80%) and validation (20%) cohorts. We compared the performance of all models using area under the curve (AUC) and average accuracy of validation cohorts and calculated the 10 most important features of the best model via a class activation map. Based on the ROI of the whole tumor, the predictive capacity of the T1CE and ADC model achieved the highest AUC value of 0.85. Based on the ROI of the tumor core, the T1CE and ADC model achieved the highest AUC value of 0.90. After comparison, the T1CE combined with the ADC model based on the ROI of the tumor core exhibited the best performance, with the highest average accuracy (0.91) and AUC (0.90) among all models. The deep learning method using MRI radiomics has excellent diagnostic performance with a high accuracy in predicting MGMT promoter methylation in diffuse gliomas.

14.
Neuroimage ; 54(4): 2683-94, 2011 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-21073960

RESUMEN

Small-world organization is known to be a robust and consistent network architecture, and is a hallmark of the structurally and functionally connected human brain. However, it remains unknown if the same organization is present in directed influence brain networks whose connectivity is inferred by the transfer of information from one node to another. Here, we aimed to reveal the network architecture of the directed influence brain network using multivariate Granger causality analysis and graph theory on resting-state fMRI recordings. We found that some regions acted as pivotal hubs, either being influenced by or influencing other regions, and thus could be considered as information convergence regions. In addition, we observed that an exponentially truncated power law fits the topological distribution for the degree of total incoming and outgoing connectivity. Furthermore, we also found that this directed network has a modular structure. More importantly, according to our data, we suggest that the human brain directed influence network could have a prominent small-world topological property.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/fisiología , Imagen por Resonancia Magnética , Red Nerviosa/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto Joven
15.
Hum Brain Mapp ; 32(6): 883-95, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20533558

RESUMEN

Studies of in mesial temporal lobe epilepsy (mTLE) patients with hippocampal sclerosis (HS) have reported reductions in both functional and structural connectivity between hippocampal structures and adjacent brain regions. However, little is known about the connectivity among the default mode network (DMN) in mTLE. Here, we hypothesized that both functional and structural connectivity within the DMN were disturbed in mTLE. To test this hypothesis, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) were applied to examine the DMN connectivity of 20 mTLE patients, and 20 gender- and age-matched healthy controls. Combining these two techniques, we explored the changes in functional (temporal correlation coefficient derived from fMRI) and structural (path length and connection density derived from DTI tractography) connectivity of the DMN. Compared to the controls, we found that both functional and structural connectivity were significantly decreased between the posterior cingulate cortex (PCC)/precuneus (PCUN) and bilateral mesial temporal lobes (mTLs) in patients. No significant between-group difference was found between the PCC/PCUN and medial prefrontal cortex (mPFC). In addition, functional connectivity was found to be correlated with structural connectivity in two pairwise regions, namely between the PCC/PCUN and bilateral mTLs, respectively. Our results suggest that the decreased functional connectivity within the DMN in mTLE may be a consequence of the decreased connection density underpinning the degeneration of structural connectivity.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/fisiopatología , Epilepsia del Lóbulo Temporal/fisiopatología , Vías Nerviosas/fisiopatología , Adolescente , Adulto , Imagen de Difusión Tensora , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Adulto Joven
16.
Hum Brain Mapp ; 32(1): 154-61, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21157880

RESUMEN

Although the brain areas in the default-mode network (DMN) act in a coordinated way during rest, the activity levels in the individual areas of the DMN are highly heterogeneous. The relation between the activity levels and the pattern of causal interaction among the DMN areas remains unknown. In the present fMRI study, seven nodes of the DMN were identified and their activity levels were rank-ordered based on a power spectral analysis of the resting blood oxygenation level-dependent (BOLD) signals. Furthermore, the direction of information flow among these DMN nodes was determined using Granger causality analysis and graph-theoretic methods. We found that the activity levels in these seven DMN nodes had a highly consistent hierarchical distribution, with the highest activity level in the posterior cingulate/precuneus cortices, followed by ventral medial prefrontal cortex and dorsal medial prefrontal cortex, and with the lowest level in the left inferior temporal gyrus. Importantly, a significant correlation was found between the activity levels and the In-Out degrees of information flow across the DMN nodes, suggesting that Granger causal influences can be used to predict BOLD activity levels. These findings shed light on the dynamical organization of cortical neuronal networks and may provide the basis for characterizing network disruption by brain disorders.


Asunto(s)
Encéfalo/fisiología , Imagen por Resonancia Magnética/métodos , Red Nerviosa/fisiología , Neuronas/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino
17.
J Neuroradiol ; 38(5): 298-303, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21354624

RESUMEN

BACKGROUND AND PURPOSE: Generalized tonic-clonic seizures (GTCS) comprise a common subsyndrome of idiopathic generalized epilepsy (IGE). Previous studies found that patients with GTCS had structural abnormalities in a few specific brain regions. However, the underlying clinical cause leading to these abnormalities remains unclear. The present study aimed to explore the relationship between changes in gray-matter (GM) volume and duration of epilepsy, based on GM volume differences observed between GTCS patients and healthy controls. PATIENTS AND METHODS: Voxel-based morphometry (VBM) analysis with DARTEL (diffeomorphic anatomical registration through exponential Lie algebra) was used to investigate GM volume differences in 31 GTCS patients compared with 37 age- and gender-matched healthy controls. Voxel-based correlation analysis was used to explore the relationship between GM volume and duration of epilepsy in GTCS patients. RESULTS: Compared with healthy controls, GTCS patients showed significant decreases in GM volume in the bilateral thalami, frontal lobe, insula and cerebellum. In addition, GM volume in the bilateral thalami and left medial frontal gyrus had a negative correlation with duration of epilepsy. CONCLUSION: GM volume changes in the thalamus and frontal lobe were associated with progressive epileptic seizures. The results indicate the presence of an abnormal thalamocortical network, which may reflect an underlying pathophysiological mechanism of GTCS.


Asunto(s)
Epilepsia Tónico-Clónica/patología , Lóbulo Frontal/patología , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Neuronas/patología , Tálamo/patología , Adulto , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
18.
Front Neurosci ; 15: 640016, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33867922

RESUMEN

We aimed to determine the alterations in the subcortical structures of patients with idiopathic generalized epilepsy with tonic-clonic seizures (IGE-GTCS) via MRI volumetry and vertex-based shape analysis and to evaluate the relationships between MRI measures and drug responses. In a follow-up sample of 48 patients with IGE-GTCS and 48 matched normal controls (NCs), high-resolution 3D T1WI was performed at baseline. After 1 year of follow-up, 31 patients were classified as seizure free (SF) and 17 as drug resistant (DR). The volumes of subcortical structures were extracted, and vertex-based shape analysis was performed using FSL-Integrated Registration and Segmentation Toolbox (FSL-FIRST). Comparisons among groups were calculated adjusting for covariates [age, sex, and intracranial volume (ICV)]. Analysis of the relationships among imaging biomarkers along with frequency and duration was assessed using partial correlations. The differential imaging indicators were used as features in a linear support vector machine (LSVM). The DR group displayed significant regional atrophy in the volume of the left amygdala compared with NCs (p = 0.004, false discovery rate corrected) and SF patients (p = 0.029, uncorrected). Meanwhile, vertex-based shape analysis showed focal inward deformation in the basolateral subregion of the left amygdala in DR compared with the results for SF and NC (p < 0.05, FWE corrected). There were significant correlations between the volume changes and seizure frequency (r = -0.324, p = 0.030) and between shape (r = -0.438, p = 0.003) changes and seizure frequency. Moreover, the volume of the left thalamus in the DR group was significantly correlated with seizure frequency (r = -0.689, p = 0.006). The SVM results revealed areas under the receiver operating characteristic curve of 0.82, 0.68, and 0.88 for the classification between SF and DR, between SF and NC, and between DR and NC, respectively. This study indicates the presence of focal atrophy in the basolateral region of the left amygdala in patients with IGE drug resistance; this finding may help predict drug responses and suggests a potential therapeutic target.

19.
Zhonghua Yi Xue Za Zhi ; 90(39): 2740-4, 2010 Oct 26.
Artículo en Zh | MEDLINE | ID: mdl-21162908

RESUMEN

OBJECTIVE: To investigate the radiographic and computerized tomographic features of chest in patients with acute chlorine poisoning and its diagnostic value. METHODS: Twenty-eight cases of chlorine poisoning were reviewed. And their radiographic and computerized tomographic features were compared and analyzed. RESULTS: Radiographic findings: among 28 patients, 9 cases were normal and 2 cases had no abnormalities on the first chest X-ray and became abnormal one or two days later. And there were abnormal findings in first chest X-ray in 17 patients:acute tracheal inflammation of peribronchitis (n = 3), acute chemical bronchopneumonia (n = 6) and diffuse interstitial and central pulmonary edema (n = 8). CT manifestations: At Days 1-3, the patients of mild poisoning had scattered patchy dense shadow; those of moderate to severe poisoning showed multiple patchy or diffuse infiltration (ground-glass opacity). And partial consolidation, air bronchogram and pleural effusion could be observed. At Days 4-10, the manifestations of mild poisoning were largely absorbed; those of moderate to severe poisoning manifested the absorption of diffuse or multiple patchy effusion and a fading of shadow. And the size of lung consolidation became smaller than before. At Day 10 after onset, 4 patients completely recovered. At Days 30-40, 6 cases showed traces of fibrous shadow and one case showed small punctiform opacities in both lungs. And at Day 42, there was slight ground-glass change. CONCLUSION: Acute chlorine gas poisoning in varying degrees may manifest acute bronchial pneumonia and acute pulmonary edema. During treatment, a series of chest X-ray examinations will help to follow the changes of disease. And CT examination can offer a more accurate evaluation of lung lesions.


Asunto(s)
Bronconeumonía/diagnóstico por imagen , Cloro/envenenamiento , Intoxicación por Gas/diagnóstico por imagen , Edema Pulmonar/diagnóstico por imagen , Adolescente , Adulto , Bronconeumonía/etiología , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Edema Pulmonar/etiología , Radiografía Torácica , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Adulto Joven
20.
Respir Med ; 165: 105920, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32174452

RESUMEN

AIM: Interstitial lung disease (ILD) is an extra-muscular manifestation of antisynthetase syndrome (ASS). The aim of this study is to analyze the clinical characteristics of anti-EJ associated ILD in a large cohort of patients. METHODS: Retrospective cohort study of patients with anti-EJ associated ILD. All available data of clinical and laboratory characteristics, pulmonary function tests, laboratory parameters, high resolution computed tomography (HRCT) and treatment were collected and analyzed from medical records. RESULTS: We identified 51 subjects. Average age at diagnosis was 55.6 years. Thirty-two of 51 patients were female. Concurrent autoantibodies against Ro52 were seen in 92.2% patients studied. HRCT patterns were mainly non-specific interstitial pneumonia (NSIP). The predominant myositis subset was amyopathic dermatomyositis (ADM) (41.2%) followed by dermatomyositis and polymyositis. Thirty-four patients improved on corticosteroids alone or in combination with immunosuppressive drugs as treatment and ten patients were stabilized. However, eleven patients (21.6%) initially improved during 12.0 ± 4.4 months, then progressively recurred despite steroid treatment (mean prednisone dose 11.6 ± 3.5 mg). The recurrence group included a significantly higher proportion of patients with NSIP pattern (p < 0.05). In the literature review the most common manifestations of anti-EJ ASS were ILD (89.3%) and myositis (58.9%). CONCLUSION: ILD are common features of the anti-EJ ASS. Patients with anti-EJ ILD often had an onset of ILD with lower lung-predominant opacities and NSIP. Although the disease responded well to the initial combination therapy of corticosteroid and immunosuppressant, recurrence was frequent. NSIP pattern was significantly more frequent in the recurrence group.


Asunto(s)
Enfermedades Pulmonares Intersticiales/diagnóstico , Miositis/diagnóstico , Corticoesteroides/administración & dosificación , Autoanticuerpos/sangre , Estudios de Cohortes , Quimioterapia Combinada , Femenino , Humanos , Inmunosupresores/administración & dosificación , Enfermedades Pulmonares Intersticiales/etiología , Enfermedades Pulmonares Intersticiales/fisiopatología , Masculino , Registros Médicos , Persona de Mediana Edad , Miositis/complicaciones , Miositis/tratamiento farmacológico , Miositis/etiología , Miositis/fisiopatología , Recurrencia , Pruebas de Función Respiratoria , Estudios Retrospectivos , Ribonucleoproteínas/inmunología , Tomografía Computarizada por Rayos X
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