1,721,014 research outputs found
Mitochondrial alterations in muscle biopsies of patients on statin therapy
No full textClinical and biopsy study of nine patients on statin therapy suffering from various myopathic syndromes is reported. Biopsy findings showed non specific myopathic signs and mitochondrial changes, such as subsarcolemmal accumulation, morphological alterations, lipid increase and Cox-negative fibers. These findings confirm that statins may cause muscle damage and impair oxidative metabolism
Systemic blood pressure profile in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
No full textBACKGROUND AND PURPOSE:
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic form of subcortical ischemic vascular dementia (SIVD). The most common vascular risk factors are unremarkable in CADASIL; however, studies on systemic blood pressure (BP) changes over time are substantially lacking. Because BP instability is a relevant risk factor for developing or worsening white matter changes in sporadic SIVD, we aimed to study the BP profile of CADASIL to investigate its relationship with cognitive decline and white matter injury.
METHODS:
Twenty-four-hour ambulatory BP monitoring was performed in a group of 14 CADASIL patients (12 males and 2 females) and in a group of 15 healthy age-matched control subjects. The following BP variables were compared between the 2 groups: mean daytime and nighttime systolic, diastolic, and mean arterial BP (SABPday, DABPday, and MABPday, and SABPnight, DABPnight, and MABPnight) and nocturnal percentage decline in arterial BP (%MABP reduction). Cognitive performances were tested by mini mental status examination (MMSE), and brain MRI was performed to extrapolate the T2-weighted lesion volume (LV) in each CADASIL patient. The 24-hour arterial BP variables were compared between CADASIL and controls. In addition, for CADASIL patients only, MMSE, LV, and age were compared with each pressure variable.
RESULTS:
Patients with CADASIL showed a significant reduction (P<0.05) of SABPday, DABPday, MABPday and %MABP decline with respect to controls. In addition, MMSE of CADASIL subjects correlated significantly (P<0.0001) with daytime MABP.
CONCLUSIONS:
The low systemic BP profile observed in CADASIL patients was specifically attributable to reduced diurnal BP values. This may further affect cerebral hemodynamics and increase the risk of cognitive impairment in these patients. The pathogenesis of abnormal BP profile in CADASIL remains to be clarified. It is likely that central and peripheral mechanisms controlling BP variations are involve
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mapping the progressive treatment-related reduction of Active MRI lesions in multiple sclerosis
Full text linkObjective: To assess treatment-related spatio-temporal dynamics of active MRI lesions in relapsing-remitting multiple sclerosis (RRMS) patients. Methods: We performed a post-hoc analysis of MRI data acquired at weeks 4, 8, 12, and 16, in RRMS patients from the multicenter randomized IMPROVE study, which compares patients treated with 44 mcg subcutaneous interferon β-1a three times weekly (n = 120) versus placebo (n = 60). We created lesion probability maps (LPMs) of the cumulative combined unique active (CUA) lesions in each patient group at each time point. Group differences were tested in terms of lesion spatial distribution and frequency of occurrence. Results: Spatial distribution of CUA lesions throughout the study was less widespread in the treated than placebo group, with a 50% lower lesion accrual (24 vs. 48 cm3/month). Similar results were obtained with the WM tract analysis, with a reduction ranging from −47 to −66% in the treated group (p < 0.001). On voxel-wise analysis, CUA lesion frequency was lower in the treated group than the placebo group at week 4 (p = 0.07, corrected), becoming particularly pronounced (p ≤ 0.03, corrected) from week 8 onwards in large clusters of WM tracts, with peaks along fronto-parietal parts of the corticospinal tract, thalamic radiation, and superior longitudinal fascicle. Conclusion: LPM showed, in the short term, a treatment-related reduction of MRI lesion activity in RRMS patients in specific, clinically relevant brain locations. Such a quantitative approach might be a promising additional endpoint in future MS studies alongside the number and volume of WM lesions. Clinical Trial Registration: ClinicalTrials.gov identifier NCT00441103
Voxel-wise assessment of progression of regional brain atrophy in relapsing-remitting multiple sclerosis
No full textOBJECTIVE:
To perform voxel-wise assessments of regional brain atrophy state and rate in subjects with relapsing-remitting (RR) multiple sclerosis (MS).
BACKGROUND:
Recently, attention has focused on defining the tissue compartments and regions within which brain atrophy occurs. These regional measures of brain volume changes may help to better define the nature of the pathology underlying MS. In this context, specific regional measures of grey matter (GM) volume changes can be obtained by using the voxel-based morphometry (VBM) approach.
METHODS:
Fifty-nine subjects with RR MS underwent conventional MRI at baseline and after a mean follow-up period of 3 years. Cross-sectionally, two VBM analyses (SPM-VBM, based on the Statistical Parametric Mapping software package, and FSL-VBM, based on the FMRIB Software Library tools) were performed to assess cortical GM volumes in RR MS patients compared to 25 age- and sex-matched normal controls (NC). Longitudinally, FSL-VBM and the regional extension of the SIENA method (SIENAr) were both used to assess regional brain atrophy rate in the RR MS patients and its relationship with increases in T(2)-weighted white matter (WM) lesion volume over the follow-up period.
RESULTS:
Widespread decrease in cortical GM volume was found in the RR MS patients compared to NC. Both SPM-VBM and FSL-VBM showed similar involvement of cortical regions (frontal, temporal, parietal, occipital lobes and insula), with a close correlation between the numbers of significant voxels obtained with the two different procedures (r=0.73, p<0.001). After 3-year follow-up, both FSL-VBM and SIENAr showed a further significant reduction in GM volume in the lateral frontal and parietal cortices, bilaterally. Regional volume changes also appeared significantly pronounced in correspondence to the increase in T(2)-weighted WM lesion volume over the follow-up period.
CONCLUSIONS:
By using different methodologies, we showed similar widespread tissue loss in the cerebral cortex of patients with RR MS. This brain tissue loss further progresses over time, particularly in the fronto-parietal cortex and seems to be partially dependent upon the increase of lesion load
Acute unilateral visual loss as the first symptom of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
No full textBACKGROUND:
Although cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is considered a cerebrovascular disorder with almost exclusively neurological symptoms, the arteriopathy is generalized and involves choroidal and retinal vasculature as demonstrated by fluorescein angiographic and ocular electrophysiological abnormalities. The occurrence of acute visual loss due to nonarteritic anterior ischemic optic neuropathy (NAION) has not previously been reported in CADASIL.
OBJECTIVE:
To describe acute visual loss due to NAION as a possible manifestation of CADASIL.
PATIENTS AND METHODS:
The patient was a 60-year-old man with subcortical diffuse leukoencephalopathy, multi-infarct dementia, tetraparesis, visual loss, and a family history of stroke. We performed clinical and neuro-ophthalmological evaluation, electrophysiological assessment, brain magnetic resonance imaging, and genetic screening for mutations or small deletions of the Notch3 gene, (causing CADASIL).
RESULTS:
The patient's first symptom was acute visual loss in the right eye due to NAION at age 27 years, in absence of the common cardiovascular risk factors and before any neurological impairment. The patient was reevaluated at age 60 years, and neuro-ophthalmological examination showed optic disc atrophy in the right eye with arteriolar narrowing and a reduction in visual acuity in the left eye. Fluorescein angiography of the right eye showed evidence of persistent peripapillary hypofluorescence with a retinal pigment epithelial windows defect in the inferior temporal area. Pattern reversal visual evoked potentials were abolished in the right eye. The P100 latency of the left eye was delayed and reduced in amplitude. The diagnosis of CADASIL was confirmed by molecular analysis (heterozygotes for the C406T mutation on exon 3 of the Notch3 gene). There was a family history of cerebrovascular disorders and ocular impairment.
CONCLUSIONS:
Visual loss due to transient or stable ischemic events involving the optic nerve head should be considered in the CADASIL phenotype. The possibility of CADASIL should also be evaluated in patients with NAION who do not have cardiovascular risk factors but do have a family history of stroke
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Retinal nerve fibre layer thickness, lesional load and brain atrophy in patients with cerebral autosomal dominant arteriopathy with subcortical infarct and leucoencephalopathy (CADASIL)
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