Search results for "Nerve fibers"
showing 10 items of 106 documents
Endothelial and neural factors functionally involved in the modulation of noradrenergic vasoconstriction in healthy pig internal mammary artery
2011
The role of endothelial and neural factors as modulators of neurogenic- and noradrenaline-induced vasoconstriction was examined in healthy pig internal mammary artery (IMA). Tetrodotoxin-, guanethidine-sensitive electrical field stimulation (EFS)-, and noradrenaline-elicited contractions were significantly diminished by prazosin (n=8, P0.001) and less so by rauwolscine, indicating functional α₁- and α₂-adrenoceptor-mediated noradrenergic innervation of the IMA. Endothelium removal reduced neurogenic (n=8, P0.01) but augmented noradrenaline responses (n=8, P0.01), suggesting the release of two endothelium-dependent factors with opposite effects. In the presence of endothelium, neurogenic and…
Color-coded diffusion-tensor-imaging of posterior cingulate fiber tracts in mild cognitive impairment.
2005
Abstract Different processes like microvascular dysfunction, free radical toxicity, β-amyloid deposits, and Wallerian degeneration can cause functionally relevant disturbances of cerebral neuronal networks by myelin degeneration. Color-coded diffusion-tensor-imaging (ccDTI) allows the structural identification and quantification of myelinated fiber tracts. Particularly, posterior cingulate fiber tracts, which are regarded as important neuronal substrates of the network representing memory processing can be localized only imprecisely by conventional magnetic resonance imaging techniques. The posterior cingulate bundles were assessed by ccDTI in 17 patients with amnestic mild cognitive impair…
N-Acetylaspartate/Creatine and Choline/Creatine Ratios in the Thalami, Insular Cortex and White Matter as Markers of Hypertension and Cognitive Impai…
2008
International audience; Abstract: Our objective was to investigate the influence of hypertension on N-acetylaspartate (NAA) and choline (Cho) ratios in brain tissues in a community-dwelling elderly population. Brain flexibility was also evaluated with regard to the same metabolite ratios. Proton magnetic resonance spectroscopy (MRS) and the Trail Making Test (TMT) were performed in 80 subjects (75.7 +/- 4 years old) from the Three-City Study. Fifty-eight participants had hypertension. The NAA/creatine (Cr) and Cho/Cr ratios were obtained in the insular cortex, the thalami and the deep periventricular white matter. In addition, the B-A score of the TMT was evaluated. Uniand multi-variate ana…
The influence of local capsaicin treatment on small nerve fibre function and neurovascular control in symptomatic diabetic neuropathy.
2002
Topical treatment with capsaicin cream has been shown to be successful in the treatment of different symptomatic nerve disorders like diabetic neuropathy. Conflicting data exist on the effect of capsaicin on nerve function and neurovascular control especially in patients with diabetic neuropathy. The aim of this pilot study was to investigate the impact of topical capsaicin application on small nerve fibre function and neurovascular control. Capsaicin cream was applied to the feet of 13 patients with symptomatic diabetic neuropathy over a period of 8 weeks. Before and during the treatment period, we investigated the total symptoms score, the vibration, thermal (heat and cold) and pain perce…
Association of ocular, cardiovascular, morphometric and lifestyle parameters with retinal nerve fibre layer thickness.
2017
BACKGROUND Glaucoma is a neurodegenerative disease, leading to thinning of the retinal nerve fibre layer (RNFL). The exact influence of ocular, cardiovascular, morphometric, lifestyle and cognitive factors on RNFL thickness (RNFLT) is unknown and was analysed in a subgroup of the Gutenberg Health Study (GHS). METHODS Global peripapillary RNFLT was measured in 3224 eyes of 1973 subjects (49% female) using spectral-domain optical coherence tomography (SD-OCT). The association of age, sex, ocular, cardiovascular, morphometric, lifestyle and cognitive factors on RNFLT was analysed using Pearson correlation coefficient and fitting a linear mixed model. RESULTS In the univariable analysis highest…
The Evonik-Mainz Eye Care-Study (EMECS): Development of an Expert System for Glaucoma Risk Detection in a Working Population
2015
Purpose To develop an expert system for glaucoma screening in a working population based on a human expert procedure using images of optic nerve head (ONH), visual field (frequency doubling technology, FDT) and intraocular pressure (IOP). Methods 4167 of 13037 (32%) employees between 40 and 65 years of Evonik Industries were screened. An experienced glaucoma expert (JW) assessed papilla parameters and evaluated all individual screening results. His classification into “no glaucoma”, “possible glaucoma” and “probable glaucoma” was defined as “gold standard”. A screening model was developed which was tested versus the gold-standard. This model took into account the assessment of the ONH. Valu…
Correlation of brain white matter diffusion anisotropy and mean diffusivity with reaction time in an oddball task.
2008
<i>Background:</i> Reaction time (RT) is a frequently used measure of information processing speed, but the underlying physiological and anatomical conditions are not yet fully understood. A correlation between measures of white matter (WM) ultrastructural properties and RT is expected – particularly for those WM tracts that are involved in the attentional system of the brain. <i>Methods:</i> Diffusion tensor imaging data were acquired in 43 unrelated healthy subjects (age: 22.7 ± 1.8 years), and RT was measured during an attention-requiring visual oddball task in the same scanning session. Voxel-by-voxel and region of interest analyses were performed for the large a…
Using Diffusion Tensor Imaging to Evaluate Microstructural Changes and Outcomes after Radiofrequency Rhizotomy of Trigeminal Nerves in Patients with …
2016
Trigeminal neuralgia is characterized by facial pain that may be sudden, intense, and recurrent. Our aim was to investigate microstructural tissue changes of the trigeminal nerve in patients with trigeminal neuralgia resulting from neurovascular compression by diffusion tensor imaging, and to test the predictive value of diffusion tensor imaging for determining outcomes after radiofrequency rhizotomy. Forty-three patients with trigeminal neuralgia were recruited, and diffusion tensor imaging was performed before radiofrequency rhizotomy. By selecting the cisternal segment of the trigeminal nerve manually, we measured the volume of trigeminal nerve, fractional anisotropy, apparent diffusion …
In toxic demyelination oligodendroglial cell death occurs early and is FAS independent
2010
Oligodendroglial cell death is a frequent phenomenon of many neurological diseases, e.g. in demyelinating diseases such as multiple sclerosis (MS). The underlying mechanisms are largely unknown. Here, we demonstrate that in the toxic demyelination cuprizone model, oligodendroglial cell death and downregulation of myelin genes start days after initiation of the cuprizone diet and weeks before demyelination is obvious. In early – but not in later – stages, dying oligodendrocytes express activated caspase 3, suggesting a switch from classical apoptotic pathways to caspase 3-independent mechanisms during the course of the cuprizone diet. The expression level of FAS in the corpus callosum, a cel…
Kinetic and static perimetry after 16 years and additional OCT-A analysis in eyes with long-lasting optic disc drusen
2021
The aim of the study is to evaluate the progression of visual field (VF) defects over 16 years of observation and to assess abnormalities in vessels and retinal nerve fibre layer (RNFL) thickness in patients with optic disc drusen (ODD). Both static automated perimetry (SAP) and semi-automated kinetic perimetry (SKP) were performed in 16 eyes of 8 patients (mean age 54 years) with ODD among 26 eyes of 13 patients examined 16 years before. The area of I2e, I4e, III4e, and V4e isopters was measured in deg2. The MD and PSD parameters were estimated using SAP. Optical coherence tomography angiography (OCT-A) was additionally performed in 16 ODD eyes and 16 eyes of 8 healthy subjects to estimate…