fMRI Response During Visual Motion Stimulation in Patients with Late Whiplash Syndrome

After whiplash trauma, up to one fourth of patients develop chronic symptoms including head and neck pain and cognitive disturbances. Resting perfusion single-pho ton-emission computed tomography (SPECT) found decreased temporoparietooccipi tal tracer uptake among these long-term symptomatic patients with late whiplash syn drome. As MT/MST (V5/V5a) are located in that area, this study addressed the question whether these patients show impairments in visual motion perception. We examined five symptomatic patients with late whiplash syndrome, five asymptomatic patients after whiplash trauma, and a control group of seven volunteers without the history of trauma. Tests for visual motion perception and functional magnetic resonance imaging (fMRI) measurements during visual motion stimulation were performed. Symptomatic patients showed a significant reduction in their ability to perceive coherent visual motion com pared with controls, whereas the asymptomatic patients did not show this effect. fMRI activation was similar during random dot motion in all three groups, but was signifi cantly decreased during coherent dot motion in the symptomatic patients compared with the other two groups. Reduced psychophysical motion performance and reduced fMRI responses in symptomatic patients with late whiplash syndrome both point to a functional impairment in cortical areas sensitive to coherent motion. Larger studies are needed to confirm these clinical and functional imaging results to provide a possible additional diagnostic criterion for the evaluation of patients with late whiplash syndrome

Evaluation of patients treated with natalizumab for progressive multifocal leukoencephalopathy

Background: Progressive multifocal leukoencephalopathy (PML) was reported to have developed in three patients treated with natalizumab. We conducted an evaluation to determine whether PML had developed in any other treated patients. Methods: We invited patients who had participated in clinical trials in which they received recent or long-term treatment with natalizumab for multiple sclerosis, Crohn's disease, or rheumatoid arthritis to participate. The clinical history, physical examination, brain magnetic resonance imaging (MRI), and testing of cerebrospinal fluid for JC virus DNA were used by an expert panel to evaluate patients for PML. We estimated the risk of PML in patients who completed at least a clinical examination for PML or had an MRI. Results: Of 3417 patients who had recently received natalizumab while participating in clinical trials, 3116 (91 percent) who were exposed to a mean of 17.9 monthly doses underwent evaluation for PML. Of these, 44 patients were referred to the expert panel because of clinical findings of possible PML, abnormalities on MRI, or a high plasma viral load of JC virus. No patient had detectable JC virus DNA in the cerebrospinal fluid. PML was ruled out in 43 of the 44 patients, but it could not be ruled out in one patient who had multiple sclerosis and progression of neurologic disease because data on cerebrospinal fluid testing and follow-up MRI were not available. Only the three previously reported cases of PML were confirmed (1.0 per 1000 treated patients; 95 percent confidence interval, 0.2 to 2.8 per 1000). Conclusions: A detailed review of possible cases of PML in patients exposed to natalizumab found no new cases and suggested a risk of PML of roughly 1 in 1000 patients treated with natalizumab for a mean of 17.9 months. The risk associated with longer treatment is not known

Bulk and surface plasmon polariton excitation in RuO2 for low-loss plasmonic applications in NIR

Transition-metal oxides, such as RuO2, offer an exciting alternative to conventional metals for metamaterials and plasmonic applications due to their low optical losses in the visible and near-infrared ranges. In this manuscript we report observation of optically excited surface plasmon polaritons (SPPs) and bulk plasmons in RuO2 thin films grown using DC reactive magnetron sputtering on glass and TiO2 (001) substrates. We show that both plasmon modes can exist simultaneously for the infrared region of the optical spectrum, while only the bulk plasmons are supported at higher optical frequencies. Finally, we demonstrate that the film properties can be tailored to favor excitation of either SPP or bulk plasmons. (C) 2012 Optical Society of Americ

Effect of inhomogeneities and substrate on the dynamics of the metal-insulator transition in VO2 thin films

We study the thermal relaxation dynamics of VO2 films after the ultrafast photoinduced metal-insulator transition for two VO2 film samples grown on Al2O3 and TiO2 substrates. We find two orders of magnitude difference in the recovery time (a few nanoseconds for the VO2/Al2O3 sample versus hundreds of nanoseconds for the VO2/TiO2 sample). We present a theoretical model to take into account the effect of inhomogeneities in the films on the relaxation dynamics. We obtain quantitative results that show how the microstructure of the VO2 film and the thermal conductivity of the interface between the VO2 film and the substrate affect long time-scale recovery dynamics. We also obtain a simple analytic relationship between the recovery time-scale and the film\u27s parameters

Hippocampus abnormalities in at risk mental states for psychosis? A cross-sectional high resolution region of interest magnetic resonance imaging study

Background: Hippocampal volume (HV) reduction is well documented in schizophrenia. However, it is still unclear whether this change is a pre-existing vulnerability factor, a sign of disease progression, a consequence of environmental factors, such as drug use, antipsychotic medication, or malnutrition. The timing of HV changes is not well established, but a lack of macrostructural hippocampal brain abnormalities before disease onset would rather support a neuroprogressive illness model. Aim: To investigate the timing of HV changes in emerging psychosis. Methods: A cross-sectional MRI study of manually traced HVs in 37 individuals with an At Risk Mental State (ARMS) for psychosis, 23 individuals with First-Episode Psychosis (FEP), and 22 Healthy Controls (HC) was performed. We compared left and right HVs corrected for whole brain volume across groups using analysis of covariance (ANCOVA) with gender as a covariate. Sixteen of 37 ARMS individuals developed a psychotic disorder during follow up (ARMS-T). The mean duration of follow up in ARMS was 25.1 months. Results: The overall ANCOVA model comparing left HVs across FEP, ARMS and HC indicated a significant general group effect (p < .05) with largest volumes in ARMS and smallest in FEP. ARMS-T subjects had significantly larger left HVs compared to FE but no HV differences compared to HC (p < 0.05). Over all groups, we found an asymmetry between the left and right mean HVs and a strong effect of sex. Discussion: The present study suggests that macrostructural hippocampal abnormalities probably occur in the context of the first psychotic breakdown

Hippocampal volume in subjects at high risk of psychosis: a longitudinal MRI study

The hippocampal formation has been studied extensively in schizophrenic psychoses and alterations in hippocampal anatomy have been consistently reported. Chronic schizophrenia seems to be associated with bilateral hippocampal volume (HV) reduction, while in patients with an at-risk mental state (ARMS) there are contradictory results. This is the first region of interest (ROI) based follow-up MRI study of hippocampal volume comparing ARMS individuals with and without transition to psychosis. The aim was to investigate the timing of HV changes in ARMS in the early phase of psychosis. METHODS: Magnetic resonance imaging data from 18 antipsychotic-naive individuals with an ARMS were collected within the FePsy-clinic for early detection of psychoses. During follow-up 8 subjects transitioned to psychosis (ARMS-T) and 10 did not (ARMS-NT). Subjects were re-scanned after the onset of psychosis or at the end of the follow-up if they did not develop psychosis. RESULTS: Across both groups there was a significant decrease in HV over time (p&lt;0.05). There was no significant difference in progression between ARMS-T and ARMS-NT. Antipsychotic medication at follow up was associated with increased HV (p&lt;0.05). CONCLUSIONS: We found a decrease of HV over time in subjects with an ARMS, independently of clinical outcome. We may speculate that the decrease of HV over time might reflect brain degeneration processes

Sodium intake and multiple sclerosis activity and progression in BENEFIT

OBJECTIVE: To assess whether a high-salt diet, as measured by urinary sodium concentration, is associated with faster conversion from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and MS activity and disability. METHODS: BENEFIT was a randomized clinical trial comparing early versus delayed interferon beta-1b treatment in 465 patients with a CIS. Each patient provided a median of 14 (interquartile range = 13-16) spot urine samples throughout the 5-year follow-up. We estimated 24-hour urine sodium excretion level at each time point using the Tanaka equations, and assessed whether sodium levels estimated from the cumulative average of the repeated measures were associated with clinical (conversion to MS, Expanded Disability Status Scale [EDSS]) and magnetic resonance imaging (MRI) outcomes. RESULTS: Average 24-hour urine sodium levels were not associated with conversion to clinically definite MS over the 5-year follow-up (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.67-1.24 per 1g increase in estimated daily sodium intake), nor were they associated with clinical or MRI outcomes (new active lesions after 6 months: HR = 1.05, 95% CI = 0.97-1.13; relative change in T2 lesion volume: -0.11, 95% CI = -0.25 to 0.04; change in EDSS: -0.01, 95% CI = -0.09 to 0.08; relapse rate: HR = 0.78, 95% CI = 0.56-1.07). Results were similar in categorical analyses using quintiles. INTERPRETATION: Our results, based on multiple assessments of urine sodium excretion over 5 years and standardized clinical and MRI follow-up, suggest that salt intake does not influence MS disease course or activity