Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.

Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity.

Physiological noise in human cerebellar fMRI.

OBJECTIVES: To compare physiological noise contributions in cerebellar and cerebral regions of interest in high-resolution functional magnetic resonance imaging (fMRI) data acquired at 7T, to estimate the need for physiological noise removal in cerebellar fMRI. MATERIALS AND METHODS: Signal fluctuations in high resolution (1 mm isotropic) 7T fMRI data were attributed to one of the following categories: task-induced BOLD changes, slow drift, signal changes correlated with the cardiac and respiratory cycles, signal changes related to the cardiac rate and respiratory volume per unit of time or other. [Formula: see text] values for all categories were compared across regions of interest. RESULTS: In this high-resolution data, signal fluctuations related to the phase of the cardiac cycle and cardiac rate were shown to be significant, but comparable between cerebellar and cerebral regions of interest. However, respiratory related signal fluctuations were increased in the cerebellar regions, with explained variances that were up to 80 % higher than for the primary motor cortex region. CONCLUSION: Even at a millimetre spatial resolution, significant correlations with both cardiac and respiratory RETROICOR components were found in all healthy volunteer data. Therefore, physiological noise correction is highly likely to improve the temporal signal-to-noise ratio (SNR) for cerebellar fMRI at 7T, even at high spatial resolution.

Practice variability and efficacy of clonazepam, lorazepam, and midazolam in status epilepticus: A multicenter comparison.

OBJECTIVE: Benzodiazepines (BZD) are recommended as first-line treatment for status epilepticus (SE), with lorazepam (LZP) and midazolam (MDZ) being the most widely used drugs and part of current treatment guidelines. Clonazepam (CLZ) is also utilized in many countries; however, there is no systematic comparison of these agents for treatment of SE to date. METHODS: We identified all patients treated with CLZ, LZP, or MDZ as a first-line agent from a prospectively collected observational cohort of adult patients treated for SE in four tertiary care centers. Relative efficacies of CLZ, LZP, and MDZ were compared by assessing the risk of developing refractory SE and the number of antiseizure drugs (ASDs) required to control SE. RESULTS: Among 177 patients, 72 patients (40.62%) received CLZ, 82 patients (46.33%) LZP, and 23 (12.99%) MDZ; groups were similar in demographics and SE characteristics. Loading dose was considered insufficient in the majority of cases for LZP, with a similar rate (84%, 95%, and 87.5%) in the centers involved, and CLZ was used as recommended in 52% of patients. After adjustment for relevant variables, LZP was associated with an increased risk of refractoriness as compared to CLZ (odds ratio [OR] 6.4, 95% confidence interval [CI] 2.66-15.5) and with an increased number of ASDs needed for SE control (OR 4.35, 95% CI 1.8-10.49). SIGNIFICANCE: CLZ seems to be an effective alternative to LZP and MDZ. LZP is frequently underdosed in this setting. These findings are highly relevant, since they may impact daily practice.

Gestión de información personal: elementos, actividades e integración

La gestión de información personal (personal information management, PIM) estudia cómo organizar y utilizar la información que las personas obtienen para resolver necesidades cotidianas, con el fin de aprovechar al máximo los recursos personales (tiempo, dinero, energía, atención), y así aumentar la productividad y mejorar en consecuencia la calidad de vida. Se presentan los elementos y las actividades en que se articula la PIM, y se expone cómo favorecer la integración de la información personal, en general dispersa en formas, aplicaciones y dispositivos distintos.

Los nuevos diarios digitales. Entrevista a Mario Tascón

Realizamos esta entrevista en los días previos a la aparición de La información.com el 23 de abril de 2009. En el contexto actual de crisis de los medios de comunicación en el que estamos asistiendo a importantes recortes de plantilla e incluso a cierres de cabeceras, es más novedosa si cabe la feliz noticia del nacimiento de un nuevo diario digital. El contexto parece aparentemente no ser el más propicio. ¿Cómo ves la situación actual de los medios en su conjunto y qué espacio aspira a ocupar La información.com? de comunicación en internet son una gota en el océano de la información¿. Esta es una visión ciertamente humilde que parece alejarse de la idea clásica de los medios como ¿cuarto poder¿. ¿Cuál es a tu juicio el papel de los medios de comunicación en este océano informativo que es internet?

Aspectos técnicos de la digitalización de fondos audiovisuales

El patrimonio audiovisual de archivos, bibliotecas y museos se encuentra en peligro debido al deterioro de las grabaciones en soportes magnéticos. Se presentan las alteraciones que pueden sufrir las cintas de vídeo, así como las dificultades que representa la obsolescencia de los aparatos necesarios para su lectura. Se considera que la mejor vía de preservación de las cintas de vídeo es su digitalización. Este paso no es fácil dada la complejidad de los formatos de archivos de vídeo digital, incluyendo los contenedores multimedia y los estándares de compresión de vídeo y de audio. Por ello la elección técnica tiene que estar estrechamente ligada a las necesidades de cada servicio. Esta aproximación se ilustra con el caso de los fondos videográficos de las televisiones locales.

Diagnostic methods and treatment options for focal cortical dysplasia.

Our inability to adequately treat many patients with refractory epilepsy caused by focal cortical dysplasia (FCD), surgical inaccessibility and failures are significant clinical drawbacks. The targeting of physiologic features of epileptogenesis in FCD and colocalizing functionality has enhanced completeness of surgical resection, the main determinant of outcome. Electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) and magnetoencephalography are helpful in guiding electrode implantation and surgical treatment, and high-frequency oscillations help defining the extent of the epileptogenic dysplasia. Ultra high-field MRI has a role in understanding the laminar organization of the cortex, and fluorodeoxyglucose-positron emission tomography (FDG-PET) is highly sensitive for detecting FCD in MRI-negative cases. Multimodal imaging is clinically valuable, either by improving the rate of postoperative seizure freedom or by reducing postoperative deficits. However, there is no level 1 evidence that it improves outcomes. Proof for a specific effect of antiepileptic drugs (AEDs) in FCD is lacking. Pathogenic mutations recently described in mammalian target of rapamycin (mTOR) genes in FCD have yielded important insights into novel treatment options with mTOR inhibitors, which might represent an example of personalized treatment of epilepsy based on the known mechanisms of disease. The ketogenic diet (KD) has been demonstrated to be particularly effective in children with epilepsy caused by structural abnormalities, especially FCD. It attenuates epigenetic chromatin modifications, a master regulator for gene expression and functional adaptation of the cell, thereby modifying disease progression. This could imply lasting benefit of dietary manipulation. Neurostimulation techniques have produced variable clinical outcomes in FCD. In widespread dysplasias, vagus nerve stimulation (VNS) has achieved responder rates >50%; however, the efficacy of noninvasive cranial nerve stimulation modalities such as transcutaneous VNS (tVNS) and noninvasive (nVNS) requires further study. Although review of current strategies underscores the serious shortcomings of treatment-resistant cases, initial evidence from novel approaches suggests that future success is possible.

Epilepsy priorities in Europe: A report of the ILAE-IBE Epilepsy Advocacy Europe Task Force.

The European Forum on Epilepsy Research (ERF2013), which took place in Dublin, Ireland, on May 26-29, 2013, was designed to appraise epilepsy research priorities in Europe through consultation with clinical and basic scientists as well as representatives of lay organizations and health care providers. The ultimate goal was to provide a platform to improve the lives of persons with epilepsy by influencing the political agenda of the EU. The Forum highlighted the epidemiologic, medical, and social importance of epilepsy in Europe, and addressed three separate but closely related concepts. First, possibilities were explored as to how the stigma and social burden associated with epilepsy could be reduced through targeted initiatives at EU national and regional levels. Second, ways to ensure optimal standards of care throughout Europe were specifically discussed. Finally, a need for further funding in epilepsy research within the European Horizon 2020 funding programme was communicated to politicians and policymakers participating to the forum. Research topics discussed specifically included (1) epilepsy in the developing brain; (2) novel targets for innovative diagnostics and treatment of epilepsy; (3) what is required for prevention and cure of epilepsy; and (4) epilepsy and comorbidities, with a special focus on aging and mental health. This report provides a summary of recommendations that emerged at ERF2013 about how to (1) strengthen epilepsy research, (2) reduce the treatment gap, and (3) reduce the burden and stigma associated with epilepsy. Half of the 6 million European citizens with epilepsy feel stigmatized and experience social exclusion, stressing the need for funding trans-European awareness campaigns and monitoring their impact on stigma, in line with the global commitment of the European Commission and with the recommendations made in the 2011 Written Declaration on Epilepsy. Epilepsy care has high rates of misdiagnosis and considerable variability in organization and quality across European countries, translating into huge societal cost (0.2% GDP) and stressing the need for cost-effective programs of harmonization and optimization of epilepsy care throughout Europe. There is currently no cure or prevention for epilepsy, and 30% of affected persons are not controlled by current treatments, stressing the need for pursuing research efforts in the field within Horizon 2020. Priorities should include (1) development of innovative biomarkers and therapeutic targets and strategies, from gene and cell-based therapies to technologically advanced surgical treatment; (2) addressing issues raised by pediatric and aging populations, as well as by specific etiologies and comorbidities such as traumatic brain injury (TBI) and cognitive dysfunction, toward more personalized medicine and prevention; and (3) translational studies and clinical trials built upon well-established European consortia.

High Prevalence of Signs of Renal Damage Despite Normal Renal Function in a Cohort of HIV-Infected Patients: Evaluation of Associated Factors

Renal disorders are an emerging problem in HIV-infected patients. We performed a cross-sectional study of the first 1000 HIV-infected patients attended at our HIV unit who agreed to participate. We determined the frequency of renal alterations and its related risk factors. Summary statistics and logistic regression were applied. The study sample comprised 970 patients with complete data. Most were white (94%) and men (76%). Median (IQR) age was 48 (42–53) years. Hypertension was diagnosed in 19%, dyslipidemia in 27%, and diabetes mellitus in 3%. According to the Chronic Kidney Disease Epidemiology Collaboration (CKD EPI) equation, 29 patients (3%) had an eGFR < 60 ml/min/1.73m2; 18 of them (62%) presented altered albumin/creatinine and protein/creatinine (UPC or UAC) ratios. Of the patients with eGFR> 60mL/min, it was present in 293 (30%), 38 of whom (7.1%) had UPC> 300mg/g. Increased risk of renal abnormalities was correlated with hypertension (OR, 1.821 [95%CI, 1.292;2.564]; p = 0.001), age (OR, 1.015 [95%CI, 1.001;1.030], per one year; p = 0.040), and use of tenofovir disoproxil fumarate (TDF) plus protease inhibitor (PI), (OR, 1.401 [95%CI, 1.078;1.821]; p = 0.012). Current CD4 cell count was a protective factor (OR, 0.9995 [95%CI, 0.9991;0.9999], per one cell; p = 0.035). A considerable proportion of patients presented altered UPC or UAC ratios, despite having an eGFR > 60mL/min. CD4 cell count was a protective factor; age, hypertension, and use of TDF plus PIs were risk factors for renal abnormalities. Based on our results, screen of renal abnormalities should be considered in all HIV-infected patients to detect these alterations early.

Methodology used in studies reporting chronic kidney disease prevalence : a systematic literature review.

BACKGROUND: Many publications report the prevalence of chronic kidney disease (CKD) in the general population. Comparisons across studies are hampered as CKD prevalence estimations are influenced by study population characteristics and laboratory methods. METHODS: For this systematic review, two researchers independently searched PubMed, MEDLINE and EMBASE to identify all original research articles that were published between 1 January 2003 and 1 November 2014 reporting the prevalence of CKD in the European adult general population. Data on study methodology and reporting of CKD prevalence results were independently extracted by two researchers. RESULTS: We identified 82 eligible publications and included 48 publications of individual studies for the data extraction. There was considerable variation in population sample selection. The majority of studies did not report the sampling frame used, and the response ranged from 10 to 87%. With regard to the assessment of kidney function, 67% used a Jaffe assay, whereas 13% used the enzymatic assay for creatinine determination. Isotope dilution mass spectrometry calibration was used in 29%. The CKD-EPI (52%) and MDRD (75%) equations were most often used to estimate glomerular filtration rate (GFR). CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m(2) in 92% of studies. Urinary markers of CKD were assessed in 60% of the studies. CKD prevalence was reported by sex and age strata in 54 and 50% of the studies, respectively. In publications with a primary objective of reporting CKD prevalence, 39% reported a 95% confidence interval. CONCLUSIONS: The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence. These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies, which will enhance comparability of study results.

¿Hacia una reconversión de los congresos? Propuestas para su viabilidad

Los congresos académicos ycientíficos deberían afrontar en los próximosaños una reconversión de los formatos y contenidospara poder sobrevivir. Se reflexiona sobre el valor 2.0 de los congresos y se proponen posiblessoluciones, como la vinculación a números especiales de revistas académicas consolidadas.La principal propuesta es la creación deCachus, una clasificación de congresos que permitadar más valor a éstos en los procesos de evaluación de los currículums de los investigadores.

Dirhamnosyl flavonoid and other constituents from Brillantaisia palisatii

A mixture containing sitosterol and stigmasterol; a new triterpene 3-epi-ursolic acid; another triterpene mixture comprising a-amyrin, b-amyrin and lupeol; verbascoside, a phenylpropanoid glycoside; and lespedin, a glycosyl flavonoid, were isolated. The less polar compounds (steroids and triterpenoids) were isolated from the hexane partition of the crude ethanolic extract while the more polar ones (phenylpropanoid glycoside and glycosyl flavonoid) were isolated from the ethyl acetate partition of the same extract. The structures of all compounds were established using modern spectrometric methods of elucidation. The spectroscopic data of Lespedin, a rare dirhamnosylflavonol with hypotensor activity and of the triterpene, 3-epi-ursolic acid, are also reported.

Tutoriales web: indicadores y ejemplos de buenas prácticas

Las bibliotecas universitarias realizan tutoriales web sobre una gran variedad de temáticas. Muchas veces van dirigidos a la alfabetización informacional (alfin) y a mostrar a los usuarios las mejoras tecnológicas de las interfaces de consulta interactiva. Se ofrece una metodología basada en treinta y cuatro indicadores para elaborar, evaluar y mejorar los tutoriales creados por las bibliotecas de cualquier ámbito y especialidad. Se presentan adicionalmente ejemplos de buenas prácticas que ilustran la descripción del indicador y pueden servir de referencia para los servicios que deseen crear sus propios tutoriales