Search results for "ops"
showing 10 items of 5435 documents
Modulation of cortical motor outputs by the symbolic meaning of visual stimuli.
2010
Abstract The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is p…
Discovering dynamic task-modulated functional networks with specific spectral modes using MEG.
2019
Efficient neuronal communication between brain regions through oscillatory synchronization at certain frequencies is necessary for cognition. Such synchronized networks are transient and dynamic, established on the timescale of milliseconds in order to support ongoing cognitive operations. However, few studies characterizing dynamic electrophysiological brain networks have simultaneously accounted for temporal non-stationarity, spectral structure, and spatial properties. Here, we propose an analysis framework for characterizing the large-scale phase-coupling network dynamics during task performance using magnetoencephalography (MEG). We exploit the high spatiotemporal resolution of MEG to m…
Cognitive processess and cognitive reserve in multiple sclerosis
2015
Multiple Sclerosis (MS) is characterized by motor, cognitive, and neuropsychiatric symptoms, which can occur independently. While MS is traditionally considered an inflammatory disease of the white matter, degeneration of gray matter is increasingly recognized as an important contributor to the progressive cognitive decline. A protective factor against the progression of cognitive dysfunction in MS could be the cognitive reserve, defined as resistance to brain dysfunction. Aim of the present study is to evaluate the role of cognitive reserve for different aspects of cognitive dysfunction of patients with MS. We found that patients with MS and lower cognitive reserve have poorer neuropsychol…
Maternal copper status and neuropsychological development in infants and preschool children.
2019
Introduction: Copper (Cu) is an essential element involved in biological processes; however, excessive Cu could be harmful because of its reactive nature. Very few studies have evaluated its potential neurotoxic effects. We aimed to evaluate the association between maternal Cu levels and children's neuropsychological development. Methods: Study subjects were mother-child pairs from the Spanish INMA (i.e. Childhood and Environment) Project. Cu was measured by inductively coupled plasma mass spectrometry in serum samples taken at the first trimester of pregnancy (2003-2005). Neuropsychological development was assessed using the Bayley Scales of Infant Development (BSID) at 12 months (n = 651) a…
Interrelationships between electromyographic, mechanical, muscle structure and reflex time measurements in man.
1981
Reaction time (TRT) with its premotor (PMT) and motor time (MT) components, patellar reflex time (TRfT) with its latency (LAT) and motor time (RfMT) were studied together with isometric force production and relaxation time variables in one leg isometric knee extension. These variables were intercorrelated together with muscle biopsy variables taken from m. vastus lateralis. From these computations MT proved to demonstrate significant correlations to rate of isometric force development (RFD) (P less than 0.001), maximum force (P0) (P less than 0.001) and per cent distribution of ST fibers (P less than 0.001). It is speculated that these relationships are determined by the pattern of the moto…
Extremely High Mutation Rate of HIV-1 In Vivo.
2015
Rates of spontaneous mutation critically determine the genetic diversity and evolution of RNA viruses. Although these rates have been characterized in vitro and in cell culture models, they have seldom been determined in vivo for human viruses. Here, we use the intrapatient frequency of premature stop codons to quantify the HIV-1 genome-wide rate of spontaneous mutation in DNA sequences from peripheral blood mononuclear cells. This reveals an extremely high mutation rate of (4.1 ± 1.7) × 10−3 per base per cell, the highest reported for any biological entity. Sequencing of plasma-derived sequences yielded a mutation frequency 44 times lower, indicating that a large fraction of viral genomes …
Spectrum of histopathologic findings in patients with achalasia reflects different etiologies
2006
Background: The etiology of achalasia is still unknown. The aim of the present study was to illucidate its underlying pathologies and their chronology by investigation of esophageal specimens in patients undergoing surgery (esophageal resection or myotomy) for achalasia. Methods: In 17 patients with achalasia, histopathologic examinations of the esophageal wall focussing on the myenteric plexus were performed. Preoperative diagnosis was based on clinical evaluation, esophagogastroscopy, barium esophagogram in all, and esophageal manometry in eight patients. The median age at the time of surgery was 54 years (range: 14–78 years). In eight cases, the complete esophageal, body and in nine ca…
Viral and host factors in the prediction of response to interferon-alpha therapy in chronic hepatitis C after long-term follow-up.
1998
Acute infection with hepatitis C virus (HCV) develops into a chronic hepatitis in about 50-70% of patients. Treatment of these patients with interferon-alpha (IFN-alpha) results in a sustained long-term response in only 15-20% but causes numerous unwanted side-effects in a higher percentage of patients. The aim of our study was to define host or viral parameters that would allow identification of responders and non-responders to IFN-alpha prior to the onset of treatment. We studied a group of 87 patients suffering from chronic hepatitis C who were treated with IFN-alpha. After long-term follow-up, 18 patients (21%) showed a sustained response to IFN-alpha therapy (normalization of serum tra…
Quality of life in drug-resistant epilepsy: relationships with negative affectivity, memory, somatic symptoms and social support
2018
Objective: To investigate the relative contribution of factors non-directly related to seizures such as negative affectivity, social support, somatic symptoms and memory performance on quality of life (QOL) in patients with drug-resistant epilepsy. Methods: This is a cross-sectional study. Seventy patients with drug-resistant epilepsy were consecutively recruited from the inpatient Epilepsy Unit, Hospital Universitario y Politecnico La Fe, between April 2015 and October 2017. Medical history provided demographic characteristics of the patients (sex, age, and educational level), and clinical data (age at epilepsy onset, duration of epilepsy in years, frequency of seizures per month, type of …
[Conservative treatment of locally advanced bladder carcinoma: neoadjuvant chemotherapy, TUR and radiotherapy. Results in 40 patients]
1998
to assess the results of bladder preservation in infiltrating bladder cancer. The potential for neoadjuvant chemotherapy followed by extensive TUR and radiotherapy was investigated in 40 patients with T2-T4a G2-G3 bladder carcinoma.from 1983 to 1995, 40 patients were submitted to bladder-sparing treatment consisting of neoadjuvant chemotherapy, extensive, TUR and radiotherapy. Most patients had T3G3 cancer. Cystectomy was not performed due to patient" choice in 29 cases (72.5%), for severe pulmonary or cardiovascular disease in disease in 9 patients (22.5) and age over 80 in 2 (5%) patients. A deep TUR-biopsy was performed before and after chemotherapy and an extensive TUR was repeated at t…