Search results for " fiber"
showing 10 items of 1776 documents
Roles of capsaicin-insensitive nociceptors in cutaneous pain and secondary hyperalgesia.
2001
Polymodal nociceptors respond to mechanical, thermal and chemical stimuli. Whereas sensitivities to heat and to the irritant substance capsaicin have recently been linked via the properties of the vanilloid receptor type 1 receptor ion channel, sensitivity to noxious mechanical stimuli such as the pinpricks used in clinical neurology seems to be unrelated. We investigated the peripheral neural basis of pinprick pain using quantitative psychophysical techniques combined with selective conduction block by nerve compression and selective desensitization by topical capsaicin treatment. Complete A-fibre block by compression of the superficial radial nerve (criterion: loss of first pain sensation…
Spinal Endocannabinoids and CB 1 Receptors Mediate C-Fiber–Induced Heterosynaptic Pain Sensitization
2009
Plastic Pain Perception Drugs and endocannabinoids acting on cannabinoid (CB) receptors have potential in the treatment of certain types of pain. In the spinal cord they are believed to suppress nociception, the perception of pain and noxious stimuli. Pernia-Andrade et al. (p. 760 ) now find that endocannabinoids, which are released in spinal cord by noxious stimulation, may promote rather than inhibit nociception by acting on CB1 receptors. Endocannabinoids not only depress transmission at excitatory synapses in the spinal cord, but also block the release of inhibitory neurotransmitters, thereby facilitating nociception.
PREVALENCE AND ASSOCIATIONS OF MYELINATED RETINAL NERVE FIBERS
2016
PURPOSE To determine the prevalence, ocular, and systemic associations of myelinated retinal nerve fibers (MRNF) in a Caucasian cohort. METHODS The Gutenberg Health Study (GHS) is a population-based, prospective cohort study encompassing 15,010 subjects in Germany. Gutenberg Health Study participants, aged 35 to 74 years, stratified for gender, decades of age, and residence were examined for ophthalmologic and systemic conditions. Optic disc centered and macular photographs were reviewed for the presence of MRNF. RESULTS In 25,728 eyes of 12,906 participants (86.0% of the cohort), the prevalence of MRNF was 0.4%. In a binary logistic regression analysis, MRNF was positively associated with …
The cell-specific expression of metalloproteinase-disintegrins (ADAMs) in inflammatory myopathies
2007
Inflammatory cell invasion and cytokine activation are important steps in the pathogenesis of immune-mediated diseases of muscle. Metalloproteinase-disintegrins (ADAMs) are considered to play a critical role in leukocyte migration by promoting cellular adhesion, cleavage of molecules of the extracellular matrix and shedding of membrane bound cytokines. Here, we report the expression patterns of ADAM8, ADAM9, ADAM10, ADAM12, ADAM17 and ADAM19 in cultured human myoblasts and peripheral blood mononuclear cells (PBMCs) in vitro, as well as in biopsies from patients suffering from polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM) and non-inflammatory controls. We observed an…
Medial gastrocnemius muscle behavior during human running and walking.
2007
Utilization of elastic energy in the tendinous tissues (TT) of the human skeletal muscle may be task dependent. The present study was designed to investigate this problem by comparing the fascicle-TT interaction of the medial gastrocnemius muscle (MG) during ground contact of running and walking. Seven subjects ran and walked with a natural cadence. Ankle and knee joint angular data were recorded by electrogoniometers for estimating the entire MG muscle-tendon unit (MTU) length, together with the ground reaction forces. The MG fascicle length was measured by using the high-speed ultrasound image scanning during movements. The results showed that in running, after the rapid early fascicle st…
Interaction between fascicle and tendinous tissues in short-contact stretch-shortening cycle exercise with varying eccentric intensities
2005
The interaction between fascicle and tendinous tissues (TT) in short-contact drop jumps (DJ) with three different drop heights [low (Low), optimal (OP), and high (High)] was examined with 11 subjects. The ground reaction force (F z) and ankle and knee joint angles were measured together with real-time ultrasonography (fascicle length) and electromyographic activities of the medial gastrocnemius (MG) and vastus lateralis (VL) muscles during the movement. With increasing drop height, the braking force and flight time increased from Low to OP ( P < 0.05). In High, the braking force increased but the flight time decreased compared with OP ( P < 0.05). During contact of Low and OP conditi…
Catecholamine release in human skin--a microdialysis study.
2003
Dermal microdialysis might be a promising tool to investigate properties of sympathetic neurons in the skin as investigation of peripheral noradrenergic neurons in humans usually relies on highly variable vasoconstrictor reflexes or on indirect measurements like skin temperature recordings. To evaluate this technique, 21 experiments were performed in 15 healthy subjects with four intracutaneous microdialysis fibers (diameter, 200 microm; cutoff, 5 kDa) at hands or feet. After 60 min, saline perfusion tyramine at concentrations of 0.195 to 200 microg/ml was applied for 15 min followed by a 15-min saline perfusion again. Catecholamine concentrations were detected through high-performance liqu…
Interrelationships between Muscle Structure, Muscle Strength, and Running Economy
2003
The present study was designed to investigate possible differences in running economy (RE) among elite middle-distance runners by examining muscle structure and maximal isometric force (MVC).Ten young male runners ran at six different running speeds. During the running bouts, respiratory gases, and blood lactate were measured. Muscle biopsies were obtained from the vastus lateralis muscle for analyzing fiber type distribution, muscle fiber area, myosin heavy chain (MHC) composition, activities of a number of metabolic enzymes (citrate synthase, lactate dehydrogenase, phosphofruktokinase, and 3-hydroxyacyl-CoA-dehydrogenase), and titin isoforms.Energy expenditure (EE) increased linearly up t…
Bilateral and Unilateral Neuromuscular Function and Muscle Cross-Sectional Area in Middle-Aged and Elderly Men and Women
1996
Forty-eight healthy men (M) and women (W), divided into two different age groups, i.e., M50 yrs (range 44-57; n = 12), W50 yrs (range 43-57; n = 12), M70 yrs (range 59-75; n = 12), and W70 yrs (range 62-75; n = 12), volunteered as subjects for examination of muscle cross-sectional area (CSA), maximal voluntary forces, force-time curves, and electromyographic activity of the knee extensor muscles during bilateral and unilateral isometric contractions. The maximal bilateral knee extension force and the average CSA values in M50 were greater (p < .05) than in M70 and in W50 were greater (p < .05-.001) than those recorded for W70. The early forces in the force-time curve were greater (p < .05) …
Differential effect of Incobotulinumtoxin A on pain, neurogenic flare and hyperalgesia in human surrogate models of neurogenic pain
2017
Background: The effectiveness of Botulinum-neurotoxin A (BoNT/A) to treat pain in human pain models is very divergent. This study was conducted to clarify if the pain models or the route of BoNT/A application might be responsible for these divergent findings. Methods: Sixteen healthy subjects (8 males, mean age 27 ± 5 years) were included in a first set of experiments consisting of three visits: (1) Visit: Quantitative sensory testing (QST) was performed before and after intradermal capsaicin injection (CAPS, 15 μg) on one thigh and electrical current stimulation (ES, 1 Hz) on the contralateral thigh. During stimulation pain and the neurogenic flare response (laser-Doppler imaging) were ass…