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1.
Hum Brain Mapp ; 44(17): 5729-5748, 2023 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-37787573

RESUMEN

Despite the known benefits of data-driven approaches, the lack of approaches for identifying functional neuroimaging patterns that capture both individual variations and inter-subject correspondence limits the clinical utility of rsfMRI and its application to single-subject analyses. Here, using rsfMRI data from over 100k individuals across private and public datasets, we identify replicable multi-spatial-scale canonical intrinsic connectivity network (ICN) templates via the use of multi-model-order independent component analysis (ICA). We also study the feasibility of estimating subject-specific ICNs via spatially constrained ICA. The results show that the subject-level ICN estimations vary as a function of the ICN itself, the data length, and the spatial resolution. In general, large-scale ICNs require less data to achieve specific levels of (within- and between-subject) spatial similarity with their templates. Importantly, increasing data length can reduce an ICN's subject-level specificity, suggesting longer scans may not always be desirable. We also find a positive linear relationship between data length and spatial smoothness (possibly due to averaging over intrinsic dynamics), suggesting studies examining optimized data length should consider spatial smoothness. Finally, consistency in spatial similarity between ICNs estimated using the full data and subsets across different data lengths suggests lower within-subject spatial similarity in shorter data is not wholly defined by lower reliability in ICN estimates, but may be an indication of meaningful brain dynamics which average out as data length increases.


Asunto(s)
Mapeo Encefálico , Imagen por Resonancia Magnética , Humanos , Mapeo Encefálico/métodos , Imagen por Resonancia Magnética/métodos , Reproducibilidad de los Resultados , Red Nerviosa/diagnóstico por imagen , Encéfalo/diagnóstico por imagen
2.
Neuroimage ; 251: 119013, 2022 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-35189361

RESUMEN

Resting-state functional magnetic resonance imaging is currently the mainstay of functional neuroimaging and has allowed researchers to identify intrinsic connectivity networks (aka functional networks) at different spatial scales. However, little is known about the temporal profiles of these networks and whether it is best to model them as continuous phenomena in both space and time or, rather, as a set of temporally discrete events. Both categories have been supported by series of studies with promising findings. However, a critical question is whether focusing only on time points presumed to contain isolated neural events and disregarding the rest of the data is missing important information, potentially leading to misleading conclusions. In this work, we argue that brain networks identified within the spontaneous blood oxygenation level-dependent (BOLD) signal are not limited to temporally sparse burst moments and that these event present time points (EPTs) contain valuable but incomplete information about the underlying functional patterns. We focus on the default mode and show evidence that is consistent with its continuous presence in the BOLD signal, including during the event absent time points (EATs), i.e., time points that exhibit minimum activity and are the least likely to contain an event. Moreover, our findings suggest that EPTs may not contain all the available information about their corresponding networks. We observe distinct default mode connectivity patterns obtained from all time points (AllTPs), EPTs, and EATs. We show evidence of robust relationships with schizophrenia symptoms that are both common and unique to each of the sets of time points (AllTPs, EPTs, EATs), likely related to transient patterns of connectivity. Together, these findings indicate the importance of leveraging the full temporal data in functional studies, including those using event-detection approaches.


Asunto(s)
Mapeo Encefálico , Imagen por Resonancia Magnética , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , Neuroimagen Funcional , Humanos , Imagen por Resonancia Magnética/métodos , Red Nerviosa/diagnóstico por imagen
3.
Ann Oncol ; 33(12): 1250-1268, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36228963

RESUMEN

BACKGROUND: The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety. PATIENTS AND METHODS: One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015. RESULTS: With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome. CONCLUSION: With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.


Asunto(s)
Neoplasias de la Mama , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Ftalazinas/efectos adversos , Células Germinativas/patología , Proteína BRCA1/genética
4.
Neuroimage ; 232: 117874, 2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33609667

RESUMEN

Slot machines are a popular form of gambling, offering a tractable way to experimentally model reward processes. This study used a 3-reel slot paradigm to assess psychologically distinct phases of reward processing, reflecting anticipation, and early- and late-stage outcome processing. EEG measures of winning, nearly missing (a losing outcome revealed at the final, third reel), and "totally" missing (a losing outcome revealed earlier, at the second reel) were collected from healthy adults (n=54). Condition effects were evaluated in: i) event-related potential (ERP) components reflecting anticipatory attention (stimulus preceding negativity, SPN) and outcome processing (reward positivity, RewP and late-positive potential, LPP) and ii) total power and phase synchrony of theta and delta band oscillations. Behaviorally, trial initiation was fastest after a near miss outcome and slowest after a winning outcome. As expected, a significant SPN was observed for possible wins (AA) vs. total misses (AB), consistent with reward anticipation. Larger win (AAA) vs. near miss (AAB) amplitudes were observed for the RewP; LPP amplitudes were largest for wins (AAA), intermediate for near misses (AAB), and smallest for total misses (ABC), reflecting significant early (RewP) and late-stage (LPP) outcome processing effects. There was an effect of reel position on the RewP, with larger amplitude in the final reel (AAA-AAB) relative to the 2nd-reel locked difference waves (AA-AB). Across all outcomes, near misses elicited the largest and most phase-synchronized theta responses, while wins elicited larger and more phase-synchronized delta responses than total misses, with delta band measures not distinguishing between near misses and wins. . Phase locking measures contrasting win vs. near miss delta and theta synchronization, within time windows corresponding to ERP measurements, covaried with RewP, but not SPN or LPP, amplitude. Lastly, EEG measures showed differential relationships with age and self-reported consummatory pleasure. In the context of slot machine play, where reward anticipation and attainment place minimal demands on effort and skill, ERP and time-frequency methods capture distinct neurophysiological signatures of reward anticipation and outcome processing.


Asunto(s)
Anticipación Psicológica/fisiología , Electroencefalografía/métodos , Juego de Azar/fisiopatología , Tiempo de Reacción/fisiología , Recompensa , Percepción del Tiempo/fisiología , Adulto , Femenino , Juego de Azar/psicología , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
5.
Mol Psychiatry ; 23(5): 1261-1269, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29038599

RESUMEN

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.


Asunto(s)
Esquizofrenia/diagnóstico por imagen , Esquizofrenia/fisiopatología , Sustancia Blanca/ultraestructura , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/fisiopatología , Estudios de Cohortes , Cuerpo Calloso/fisiopatología , Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Sustancia Blanca/fisiopatología , Adulto Joven
6.
Psychol Med ; 48(15): 2492-2499, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29444726

RESUMEN

BACKGROUND: Schizophrenia (SZ) is a severe neuropsychiatric disorder associated with disrupted connectivity within the thalamic-cortico-cerebellar network. Resting-state functional connectivity studies have reported thalamic hypoconnectivity with the cerebellum and prefrontal cortex as well as thalamic hyperconnectivity with sensory cortical regions in SZ patients compared with healthy comparison participants (HCs). However, fundamental questions remain regarding the clinical significance of these connectivity abnormalities. METHOD: Resting state seed-based functional connectivity was used to investigate thalamus to whole brain connectivity using multi-site data including 183 SZ patients and 178 matched HCs. Statistical significance was based on a voxel-level FWE-corrected height threshold of p < 0.001. The relationships between positive and negative symptoms of SZ and regions of the brain demonstrating group differences in thalamic connectivity were examined. RESULTS: HC and SZ participants both demonstrated widespread positive connectivity between the thalamus and cortical regions. Compared with HCs, SZ patients had reduced thalamic connectivity with bilateral cerebellum and anterior cingulate cortex. In contrast, SZ patients had greater thalamic connectivity with multiple sensory-motor regions, including bilateral pre- and post-central gyrus, middle/inferior occipital gyrus, and middle/superior temporal gyrus. Thalamus to middle temporal gyrus connectivity was positively correlated with hallucinations and delusions, while thalamus to cerebellar connectivity was negatively correlated with delusions and bizarre behavior. CONCLUSIONS: Thalamic hyperconnectivity with sensory regions and hypoconnectivity with cerebellar regions in combination with their relationship to clinical features of SZ suggest that thalamic dysconnectivity may be a core neurobiological feature of SZ that underpins positive symptoms.


Asunto(s)
Cerebelo/fisiopatología , Corteza Cerebral/fisiopatología , Conectoma/métodos , Red Nerviosa/fisiopatología , Esquizofrenia/fisiopatología , Tálamo/fisiopatología , Adulto , Cerebelo/diagnóstico por imagen , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Esquizofrenia/diagnóstico por imagen , Tálamo/diagnóstico por imagen
7.
Suppl Clin Neurophysiol ; 62: 163-80, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24053039

RESUMEN

BACKGROUND: In electroencephalogram (EEG) studies of auditory steady-state responses (ASSRs), patients with schizophrenia show a deficit in power and/or phase-locking, particularly at the 40 Hz frequency where these responses resonate. In addition, studies of the transient gamma-band response (GBR) elicited by single tones have revealed deficits in gamma power and phase-locking in schizophrenia. We examined the degree to which the 40 Hz ASSR and the transient GBR to single tones are correlated and whether they assess overlapping or distinct gamma-band abnormalities in schizophrenia. METHODS: EEG was recorded during 40 Hz ASSR and auditory oddball paradigms from 28 patients with schizophrenia or schizoaffective disorder (SZ) and 25 age- and gender-matched healthy controls (HC). The ASSR was elicited by 500 ms click trains, and the transient GBR was elicited by the standard tones from the oddball paradigm. Gamma phase and magnitude values, calculated using Morlet wavelet transformations, were used to derive total power and phase-locking measures. RESULTS: Relative to HC, SZ patients had significant deficits in total gamma power and phase-locking for both ASSR- and GBR-based measures. Within both groups, the 40 Hz ASSR and GBR phase-locking measures were significantly correlated, with a similar trend evident for the total power measures. Moreover, co-varying for GBR substantially reduced 40 Hz ASSR power and phase-locking differences between the groups. CONCLUSIONS: 40 Hz ASSR and transient GBR measures provide very similar information about auditory gamma abnormalities in schizophrenia, despite the overall enhancement of 40 Hz ASSR total power and phase-locking values relative to the corresponding GBR values.


Asunto(s)
Trastornos de la Percepción Auditiva/etiología , Mapeo Encefálico , Ondas Encefálicas/fisiología , Potenciales Evocados Auditivos/fisiología , Esquizofrenia/complicaciones , Estimulación Acústica , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Electroencefalografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Psicoacústica , Tiempo de Reacción , Esquizofrenia/diagnóstico , Factores de Tiempo , Adulto Joven
9.
J Obstet Gynaecol ; 33(5): 463-5, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23815197

RESUMEN

Pudendal nerve blocks are a pre-requisite to forceps delivery without regional anaesthesia. Their efficacy is dependent on introducing local anaesthetic in close proximity to the pudendal nerve and allowing sufficient time for its onset of action. An audit of 57 obstetricians evaluated their clinical technique against standards using both a questionnaire and adapted model pelvis. The majority of participants were unable to describe correctly the point of infiltration and were unaware of the lag time required to effect adequate analgesia. We identify a deficiency in training and describe a method by which training can be facilitated and assessed.


Asunto(s)
Bloqueo Nervioso/normas , Obstetricia/normas , Nervio Pudendo , Femenino , Humanos , Auditoría Médica , Embarazo , Estudios Prospectivos
10.
J Neurosci Methods ; 389: 109794, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-36652974

RESUMEN

The past 10 years have seen an explosion of approaches that focus on the study of time-resolved change in functional connectivity (FC). FC characterization among networks at a whole-brain level is frequently termed functional network connectivity (FNC). Time-resolved or dynamic functional network connectivity (dFNC) focuses on the estimation of transient, recurring, whole-brain patterns of FNC. While most approaches in this area have attempted to capture dynamic linear correlation, we are particularly interested in whether explicitly nonlinear relationships, above and beyond linear, are present and contain unique information. This study thus proposes an approach to assess explicitly nonlinear dynamic functional network connectivity (EN dFNC) derived from the relationship among independent component analysis time courses. Linear relationships were removed at each time point to evaluate, typically ignored, explicitly nonlinear dFNC using normalized mutual information (NMI). Simulations showed the proposed method estimated explicitly nonlinearity over time, even within relatively short windows of data. We then, applied our approach on 151 schizophrenia patients, and 163 healthy controls fMRI data and found three unique, highly structured, mostly long-range, functional states that also showed significant group differences. In particular, explicitly nonlinear relationships tend to be more widespread than linear ones. Results also highlighted a state with long range connections to the visual domain, which were significantly reduced in schizophrenia. Overall, this work suggests that quantifying EN dFNC may provide a complementary and potentially valuable tool for studying brain function by exposing relevant variation that is typically ignored.


Asunto(s)
Imagen por Resonancia Magnética , Esquizofrenia , Humanos , Imagen por Resonancia Magnética/métodos , Dinámicas no Lineales , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , Esquizofrenia/diagnóstico por imagen
11.
Psychol Med ; 41(5): 959-69, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-20663254

RESUMEN

BACKGROUND: Patients with schizophrenia (SZ) characteristically exhibit supranormal levels of cortical activity to self-induced sensory stimuli, ostensibly because of abnormalities in the neural signals (corollary discharges, CDs) normatively involved in suppressing the sensory consequences of self-generated actions. The nature of these abnormalities is unknown. This study investigated whether SZ patients experience CDs that are abnormally delayed in their arrival at the sensory cortex. METHOD: Twenty-one patients with SZ and 25 matched control participants underwent electroencephalography (EEG). Participants' level of cortical suppression was calculated as the amplitude of the N1 component evoked by a button press-elicited auditory stimulus, subtracted from the N1 amplitude evoked by the same stimulus presented passively. In the three experimental conditions, the auditory stimulus was delivered 0, 50 or 100 ms subsequent to the button-press. Fifteen SZ patients and 17 healthy controls (HCs) also underwent diffusion tensor imaging (DTI), and the fractional anisotropy (FA) of participants' arcuate fasciculus was used to predict their level of cortical suppression in the three conditions. RESULTS: While the SZ patients exhibited subnormal N1 suppression to undelayed, self-generated auditory stimuli, these deficits were eliminated by imposing a 50-ms, but not a 100-ms, delay between the button-press and the evoked stimulus. Furthermore, the extent to which the 50-ms delay normalized a patient's level of N1 suppression was linearly related to the FA of their arcuate fasciculus. CONCLUSIONS: These data suggest that SZ patients experience temporally delayed CDs to self-generated auditory stimuli, putatively because of structural damage to the white-matter (WM) fasciculus connecting the sites of discharge initiation and destination.


Asunto(s)
Imagen de Difusión Tensora , Electroencefalografía , Retroalimentación Sensorial , Alucinaciones/fisiopatología , Vías Nerviosas , Esquizofrenia/fisiopatología , Adulto , Anciano , Corteza Auditiva/fisiopatología , Estudios de Casos y Controles , Femenino , Lóbulo Frontal/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Modelos Neurológicos , Inhibición Neural , Percepción del Habla
12.
Colorectal Dis ; 12(7 Online): e24-30, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19614668

RESUMEN

OBJECTIVE: The aim of this study was to investigate the effect of preoperative chemoradiotherapy (CRT) on nodal disease in locally advanced rectal adenocarcinoma. METHOD: Thirty-two patients staged uT3N0 and 27 patients staged uT3N1 rectal adenocarcinoma who underwent pre-CRT staging using endoscopic ultrasound or rectal protocol CT were included. The median radiation dose was 50.4 Gy (range: 45-50.4 Gy) at 1.8 Gy per fraction and all patients received concurrent 5-FU or capecitabine-based chemotherapy. Low anterior resection or abdomino-perineal resection occurred at a median of 46 days (range: 27-112 days) after CRT. RESULTS: Eleven of 32 uT3N0 patients (34.4%) and 13 of 26 uT3N1 patients (50.0%) had ypN+ (P = 0.29). For patients with uT3N0, 10 of 20 (50.0%) with ypT2-3 and 1 of 12 (8.3%) with ypT0-1 were ypN+ (P = 0.02). For patients with uT3N1, 12 of 20 (60.0%) with ypT2-3 and 1 of 6 (16.7%) with ypT0-1 were ypN+ (P = 0.16). Overall, the ypN+ rate was 11.1% in the ypT0-yT1 group compared with 55.0% in the ypT2-yT3 group (P = 003). Among patients with uT3N0 disease, the ypN+ rate in patients who had surgery > 46 days vs 46 days vs 46 days vs

Asunto(s)
Adenocarcinoma/diagnóstico , Antineoplásicos/uso terapéutico , Endosonografía/métodos , Estadificación de Neoplasias , Neoplasias del Recto/diagnóstico , Recto/patología , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/radioterapia , Colonoscopía/métodos , Relación Dosis-Respuesta en la Radiación , Estudios de Seguimiento , Humanos , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/radioterapia , Recto/diagnóstico por imagen , Estudios Retrospectivos , Resultado del Tratamiento
13.
Dis Esophagus ; 23(4): 300-8, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19732129

RESUMEN

The objective of this study is to determine the feasibility and report the outcome of patients with locally advanced esophageal cancer treated with preoperative or definitive chemoradiotherapy (CRT) using intensity-modulated radiation therapy (IMRT). Between 2003 and 2007, 30 patients with non-cervical esophageal cancer received concurrent chemotherapy and IMRT at Stanford University. Eighteen patients were planned for definitive CRT and 12 were planned for preoperative CRT. All patients had computed tomography-based treatment planning and received IMRT. The median dose delivered was 50.4 Gy. Patients planned for preoperative CRT underwent surgery 4-13 weeks (median 8.3 weeks) following completion of CRT. Median follow-up of surviving patients from start of RT was 24.2 months (range 8.2-38.3 months). The majority of tumors were adenocarcinomas (67%) and poorly differentiated (57%). Tumor location was 7% upper, 20% mid, 47% lower, and 27% gastroesophageal junction. Actuarial 2-year local-regional control (LRC) was 64%. High tumor grade was an adverse prognostic factor for LRC and overall survival (OS) (P= 0.015 and 0.012, respectively). The 2-year LRC was 83% vs. 51% for patients treated preoperatively vs. definitively (P= 0.32). The 2-year disease-free and OS were 38% and 56%, respectively. Twelve patients (40%) required feeding tube placement, and the average weight loss from baseline was 4.8%. Twelve (40%) patients experienced grade 3+ acute complications and one patient died of complications following feeding tube placement. Three patients (10%) required a treatment break. Eight patients (27%) experienced grade 3 late complications. No grade 4 complications were seen. IMRT was effective and well tolerated. Disease recurrence remains a challenge and further investigation with dose escalation to improve LRC and OS is warranted.


Asunto(s)
Adenocarcinoma/radioterapia , Carcinoma de Células Escamosas/radioterapia , Neoplasias Esofágicas/radioterapia , Radioterapia de Intensidad Modulada , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/cirugía , Terapia Combinada , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/cirugía , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Dosis de Radiación , Radioterapia de Intensidad Modulada/efectos adversos , Estudios Retrospectivos , Resultado del Tratamiento
14.
Science ; 181(4098): 465-6, 1973 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-4718116

RESUMEN

Electrical responses evoked by clicks, flashes, changes in noise level, and changes in light level were recorded from the scalps of human subjects set to detect one of the stimuli. An early negative component of the evoked responses reflects selection between sensory modalities, whereas the later positive component reflects a more complex intramodal discrimination.


Asunto(s)
Corteza Cerebral/fisiología , Potenciales Evocados , Estimulación Física , Estimulación Acústica , Electroencefalografía , Humanos , Estimulación Luminosa
15.
Schizophr Bull ; 35(1): 67-81, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19074498

RESUMEN

Deficits in the connectivity between brain regions have been suggested to play a major role in the pathophysiology of schizophrenia. A functional magnetic resonance imaging (fMRI) analysis of schizophrenia was implemented using independent component analysis (ICA) to identify multiple temporally cohesive, spatially distributed regions of brain activity that represent functionally connected networks. We hypothesized that functional connectivity differences would be seen in auditory networks comprised of regions such as superior temporal gyrus as well as executive networks that consisted of frontal-parietal areas. Eight networks were found to be implicated in schizophrenia during the auditory oddball paradigm. These included a bilateral temporal network containing the superior and middle temporal gyrus; a default-mode network comprised of the posterior cingulate, precuneus, and middle frontal gyrus; and multiple dorsal lateral prefrontal cortex networks that constituted various levels of between-group differences. Highly task-related sensory networks were also found. These results indicate that patients with schizophrenia show functional connectivity differences in networks related to auditory processing, executive control, and baseline functional activity. Overall, these findings support the idea that the cognitive deficits associated with schizophrenia are widespread and that a functional connectivity approach can help elucidate the neural correlates of this disorder.


Asunto(s)
Corteza Auditiva/fisiopatología , Lóbulo Frontal/fisiopatología , Imagen por Resonancia Magnética , Lóbulo Parietal/fisiopatología , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatología , Lóbulo Temporal/fisiopatología , Adolescente , Adulto , Anciano , Corteza Cerebral/fisiopatología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Red Nerviosa/fisiopatología , Pruebas Neuropsicológicas , Esquizofrenia/complicaciones , Tálamo/fisiopatología , Adulto Joven
16.
Schizophr Bull ; 35(1): 47-57, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18990710

RESUMEN

INTRODUCTION: Auditory hallucinations are a hallmark symptom of schizophrenia. The neural basis of auditory hallucinations was examined using data from a working memory task. Data were acquired within a multisite consortium and this unique dataset provided the opportunity to analyze data from a large number of subjects who had been tested on the same procedures across sites. We hypothesized that regions involved in verbal working memory and language processing would show activity that was associated with levels of hallucinations during a condition where subjects were rehearsing the stimuli. METHODS: Data from the Sternberg Item Recognition Paradigm, a working memory task, were acquired during functional magnetic resonance imaging procedures. The data were collected and preprocessed by the functional imaging biomedical informatics research network consortium. Schizophrenic subjects were split into nonhallucinating and hallucinating subgroups and activity during the probe condition (in which subjects rehearsed stimuli) was examined. Levels of activation from contrast images for the probe phase (collapsed over levels of memory load) of the working memory task were also correlated with levels of auditory hallucinations from the Scale for the Assessment of Positive Symptoms scores. RESULTS: Patients with auditory hallucinations (relative to nonhallucinating subjects) showed decreased activity during the probe condition in verbal working memory/language processing regions, including the superior temporal and inferior parietal regions. These regions also showed associations between activity and levels of hallucinations in a correlation analysis. DISCUSSION: The association between activation and hallucinations scores in the left hemisphere language/working memory regions replicates the findings of previous studies and provides converging evidence for the association between superior temporal abnormalities and auditory hallucinations.


Asunto(s)
Alucinaciones/diagnóstico , Alucinaciones/fisiopatología , Imagen por Resonancia Magnética , Memoria a Corto Plazo , Lóbulo Parietal/fisiopatología , Lóbulo Temporal/fisiopatología , Adolescente , Adulto , Anciano , Femenino , Lateralidad Funcional/fisiología , Alucinaciones/etiología , Humanos , Masculino , Persona de Mediana Edad , Reconocimiento en Psicología , Esquizofrenia/complicaciones , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatología , Índice de Severidad de la Enfermedad , Conducta Verbal , Adulto Joven
17.
Schizophr Bull ; 35(1): 19-31, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19042912

RESUMEN

BACKGROUND: The Functional Imaging Biomedical Informatics Network is a consortium developing methods for multisite functional imaging studies. Both prefrontal hyper- or hypoactivity in chronic schizophrenia have been found in previous studies of working memory. METHODS: In this functional magnetic resonance imaging (fMRI) study of working memory, 128 subjects with chronic schizophrenia and 128 age- and gender-matched controls were recruited from 10 universities around the United States. Subjects performed the Sternberg Item Recognition Paradigm1,2 with memory loads of 1, 3, or 5 items. A region of interest analysis examined the mean BOLD signal change in an atlas-based demarcation of the dorsolateral prefrontal cortex (DLPFC), in both groups, during both the encoding and retrieval phases of the experiment over the various memory loads. RESULTS: Subjects with schizophrenia performed slightly but significantly worse than the healthy volunteers and showed a greater decrease in accuracy and increase in reaction time with increasing memory load. The mean BOLD signal in the DLPFC was significantly greater in the schizophrenic group than the healthy group, particularly in the intermediate load condition. A secondary analysis matched subjects for mean accuracy and found the same BOLD signal hyperresponse in schizophrenics. CONCLUSIONS: The increase in BOLD signal change from minimal to moderate memory loads was greater in the schizophrenic subjects than in controls. This effect remained when age, gender, run, hemisphere, and performance were considered, consistent with inefficient DLPFC function during working memory. These findings from a large multisite sample support the concept not of hyper- or hypofrontality in schizophrenia, but rather DLPFC inefficiency that may be manifested in either direction depending on task demands. This redirects the focus of research from direction of difference to neural mechanisms of inefficiency.


Asunto(s)
Imagen por Resonancia Magnética , Memoria a Corto Plazo , Corteza Prefrontal/fisiopatología , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatología , Adolescente , Adulto , Anciano , Enfermedad Crónica , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Trastornos de la Memoria/diagnóstico , Trastornos de la Memoria/etiología , Persona de Mediana Edad , Pruebas Neuropsicológicas , Esquizofrenia/complicaciones , Índice de Severidad de la Enfermedad , Adulto Joven
18.
Ann Oncol ; 19(7): 1320-1326, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18344535

RESUMEN

BACKGROUND: Imatinib is a selective inhibitor of the BCR/ABL tyrosine kinase. The remarkable initial results of the first phase I clinical trial published in 1999 prompted the rapid initiation of large phase II trials. They also generated intense media coverage and significant interest from patients and clinicians and demand for access to imatinib before marketing approval. In response, a worldwide expanded access program (EAP) for imatinib was implemented in May 2000. PATIENTS: In total, 7380 patients with chronic myeloid leukemia (CML) and acute lymphoblastic leukemia failing prior therapies were enrolled in 106 centers in 34 countries. RESULTS: Time to progression and overall survival, as well as the safety profile, were similar to those observed in published phase II studies. At the end of the program, patients benefiting from treatment were continued on imatinib therapy by transferring to national health care systems or patient assistance programs. CONCLUSION: The imatinib EAP successfully provided therapy to patients with CML before marketing approval. The program provides an efficient framework for the development of global EAPs for innovative investigational anticancer agents in patients without a satisfactory therapeutic alternative.


Asunto(s)
Leucemia Mielógena Crónica BCR-ABL Positiva/terapia , Leucemia Mieloide de Fase Crónica/terapia , Piperazinas/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinas/uso terapéutico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Benzamidas , Niño , Ensayos Clínicos Fase I como Asunto , Ensayos Clínicos Fase II como Asunto , Progresión de la Enfermedad , Femenino , Humanos , Mesilato de Imatinib , Cooperación Internacional , Estimación de Kaplan-Meier , Leucemia Mielógena Crónica BCR-ABL Positiva/mortalidad , Leucemia Mieloide de Fase Crónica/mortalidad , Masculino , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Piperazinas/efectos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Desarrollo de Programa , Inhibidores de Proteínas Quinasas/efectos adversos , Pirimidinas/efectos adversos , Análisis de Supervivencia , Factores de Tiempo
19.
Fam Cancer ; 7(2): 125-33, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-17657584

RESUMEN

INTRODUCTION: Germline mutations of BRCA1 and BRCA2 account for the majority of hereditary breast cancers, many of which are classified as variants of unknown significance (VUS). We report the identification of a novel BRCA2 variant (c.7806-9T > G) in a Chinese family with multiple breast cancers and document it as a pathogenic mutation. METHODS: The proband in this family was diagnosed with breast cancer at age 50 with a strong family history of breast cancer. DNA and RNA were extracted from the blood of the proband and her family, and was used for BRCA gene mutation/deletion screening and RNA splicing analysis. RESULTS: BRCA2 c.7806-9T > G was identified in the proband, which was suggestive of a variant. This change was also found in two sisters of the proband with a history of breast cancer, as well as from the proband's maternal gastric cancer. The only sibling free of breast cancer did not carry the BRCA2 variant, thus demonstrating that the mutation segregates with the clinical phenotype in this family. RNA analysis on the proband blood sample revealed three aberrant splicing variants: c.7806_7874del, c.7806_7976del, and c.7806-8_7806-1ins. The latter causes a frameshift and creates a truncated protein, whilst the other two splicing variants resulted in shorter forms of the protein. CONCLUSIONS: The identified BRCA2 c.7806-9T > G [Genbank: DQ889340] was found to be pathogenic, based on aberrant splicing events resulting in the formation of truncated protein products. Thus, better understanding and classification of BRCA variants as neutral or disease causing has important implications for genetic counseling so that appropriate management can be given.


Asunto(s)
Pueblo Asiatico/genética , Neoplasias de la Mama/genética , Genes BRCA2 , Mutación , Adulto , Secuencia de Bases , Neoplasias de la Mama/patología , Femenino , Genes BRCA1 , Mutación de Línea Germinal , Humanos , Persona de Mediana Edad , Linaje , Mutación Puntual , Factores de Riesgo , Análisis de Secuencia de ADN
20.
Brain Imaging Behav ; 12(3): 615-630, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28434159

RESUMEN

Many studies have shown that schizophrenia patients have aberrant functional network connectivity (FNC) among brain regions, suggesting schizophrenia manifests with significantly diminished (in majority of the cases) connectivity. Schizophrenia is also associated with a lack of hemispheric lateralization. Hoptman et al. (2012) reported lower inter-hemispheric connectivity in schizophrenia patients compared to controls using voxel-mirrored homotopic connectivity. In this study, we merge these two points of views together using a group independent component analysis (gICA)-based approach to generate hemisphere-specific timecourses and calculate intra-hemisphere and inter-hemisphere FNC on a resting state fMRI dataset consisting of age- and gender-balanced 151 schizophrenia patients and 163 healthy controls. We analyzed the group differences between patients and healthy controls in each type of FNC measures along with age and gender effects. The results reveal that FNC in schizophrenia patients shows less hemispheric asymmetry compared to that of the healthy controls. We also found a decrease in connectivity in all FNC types such as intra-left (L_FNC), intra-right (R_FNC) and inter-hemisphere (Inter_FNC) in the schizophrenia patients relative to healthy controls, but general patterns of connectivity were preserved in patients. Analyses of age and gender effects yielded results similar to those reported in whole brain FNC studies.


Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Imagen por Resonancia Magnética , Esquizofrenia/diagnóstico por imagen , Esquizofrenia/fisiopatología , Adolescente , Adulto , Mapeo Encefálico , Femenino , Lateralidad Funcional , Humanos , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiopatología , Descanso , Adulto Joven
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