91 research outputs found
Loss of large diameter spindle afferent fibres is not detrimental to the control of body sway during upright stance: evidence from neuropathy.
No full textFifteen patients with Charcot-Marie-Tooth type 1A (CMT1A) disease and 46 normal controls were studied.
In the patients, leg muscle strength, touch-pressure, vibration and joint position sense were reduced; lower limb tendon reflexes were absent in 12 or markedly decreased. Motor and sensory conduction velocity (CV) of leg nerves was either reduced or not measurable. The Neurological Disability Score and the Neuropathy Score were obtained from clinical and electrophysiological examination, respectively. Tilt of a supporting platform elicited short- (SLR) and medium-latency (MLR) responses to stretch in the foot muscle flexor digitorum brevis (FDB) in controls. In the patients, the former response was absent and the latter delayed. These findings are in keeping with the known loss of largediameter myelinated fibres, with relative sparing of the smaller fibres. The MLR delay was fully accounted for by the slowed CV of the motor fibres. The MLR afferent time was similar to that in normal subjects. Body sway area (SA) during quiet stance was recorded with eyes open or closed, and with feet apart or together. Under all postural and visual conditions, SA was within normal range in the less severely affected patients, but was moderately increased in the patients with a more severe neuropathy score. Across all patients, no correlation was found between SA and muscle force, motor CV, touch pressure, vibration and joint position sense, considered either separately or as an aggregate. We suggest that: (1) functional integrity of the largest afferent fibres is not necessary for appropriate equilibrium control during quiet stance and (2) any unsteadiness is related to additional functional alterations in smaller fibres, most likely group II spindle afferent fibres
Association of serum triglyceride-to-HDL cholesterol ratio with carotid artery intima-media thickness, insulin resistance and nonalcoholic fatty liver disease in children and adolescents
No full textBackground and aims: The triglyceride (TG)/high-density lipoprotein-cholesterol (HDL-C) ratio has been reported as a useful marker of atherogenic lipid abnormalities, insulin resistance, and cardiovascular disease. We evaluated in a large sample of children and adolescents the association of TG/HDL-C ratio with early signs of morphological vascular changes and cardiometabolic risk factors including nonalcoholic fatty liver disease (NAFLD). Methods and results: The study population, including 548 children (aged 6-16 years), of whom 157 were normal-weight, 118 overweight, and 273 obese, had anthropometric, laboratory, liver and carotid ultrasonography (carotid artery intima-media thickness-cIMT) data collected. Subjects were stratified into tertiles of TG/HDL-C. There was a progressive increase in body mass index (BMI), BMI-SD score (SDS), waist circumference, blood pressure (BP), liver enzymes, glucose, insulin, homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein (hsCRP), and cIMT values across TG/HDL-C tertiles. The odds ratios for central obesity, insulin resistance, high hsCRP, NAFLD, metabolic syndrome, and elevated cIMT increased significantly with the increasing tertile of TG/HDL-C ratio, after adjustment for age, gender, pubertal status, and BMI-SDS. In a stepwise multivariate logistic regression analysis, increased cIMT was associated with high TG/HDL-C ratio [OR, 1.81 (95% CI, 1.08-3.04); P < 0.05], elevated BP [5.13 (95% CI, 1.03-15.08); P < 0.05], insulin resistance [2.16 (95% CI, 1.30-3.39); P < 0.01], and NAFLD [2.70 (95% CI, 1.62-4.56); P < 0.01]. Conclusion: TG/HDL-C ratio may help identify children and adolescents at high risk for structural vascular changes and metabolic derangement. (C) 2014 Elsevier B.V. All rights reserved
The shortening reaction of forearm muscles: the influence of central set.
No full textObjective: The EMG of the forearm muscles shortened by an imposed wrist joint displacement has been studied at different levels and distribution of background muscle activity and with different instructions to the subjects, in order to test the hypothesis that the recorded
EMG response (shortening reaction, ShoRe) could be deliberate in origin.
Methods: Ten normal subjects were examined. A torque motor induced 508 wrist extension or ̄exion at 5008/s. The subjects were relaxed or exerted a 10% maximal voluntary contraction. They were instructed either not to intervene, or to oppose the displacement, or else to assist
it. Several trials were repeated at different initial angles.
Results: We found a short-latency re ̄ex (SR) in the stretched muscle, be it ̄exor or extensor, and a later inconstant ShoRe in the antagonist. ShoRe latency was compatible with that of a reaction time (RT), and was not in ̄uenced by the initial wrist angle. When subjects
assisted the movement, the EMG burst in the shortening muscle was in every respect a RT; when they opposed the movement, the ShoRe disappeared. There was a strict temporal relationship between SR duration and ShoRe latency.
Conclusions:We suggest that the brain would deliberately trigger the ShoRe on recognizing the displacement direction. The occurrence of such activity in the shortened muscle makes the SR to abruptly stop. The temporal relationship between the duration of the SR and onset of
the ShoRe can be an expression of the inhibition on the SR burst by the cortical drive to the antagonist muscle being shortened, possibly through the action of spinal inhibitory interneurones. The ShoRe would complete the movement momentarily braked by the SR and redistribute the muscle tone across antagonists, appropriate for the new muscle length
Loss of large-diameter spindle afferent fibres is not detrimental to the control of body sway during upright stance: evidence from neuropathy
No full textFifteen patients with Charcot-Marie-Tooth type 1A (CMT1A) disease and 46 normal
controls were studied. In the patients, leg muscle strength, touch-pressure,
vibration and joint position sense were reduced; lower limb tendon reflexes were
absent in 12 or markedly decreased. Motor and sensory conduction velocity (CV) of
leg nerves was either reduced or not measurable. The Neurological Disability
Score and the Neuropathy Score were obtained from clinical and
electrophysiological examination, respectively. Tilt of a supporting platform
elicited short- (SLR) and medium-latency (MLR) responses to stretch in the foot
muscle flexor digitorum brevis (FDB) in controls. In the patients, the former
response was absent and the latter delayed. These findings are in keeping with
the known loss of large-diameter myelinated fibres, with relative sparing of the
smaller fibres. The MLR delay was fully accounted for by the slowed CV of the
motor fibres. The MLR afferent time was similar to that in normal subjects. Body
sway area (SA) during quiet stance was recorded with eyes open or closed, and
with feet apart or together. Under all postural and visual conditions, SA was
within normal range in the less severely affected patients, but was moderately
increased in the patients with a more severe neuropathy score. Across all
patients, no correlation was found between SA and muscle force, motor CV, touch
pressure, vibration and joint position sense, considered either separately or as
an aggregate. We suggest that: (1) functional integrity of the largest afferent
fibres is not necessary for appropriate equilibrium control during quiet stance
and (2) any unsteadiness is related to additional functional alterations in
smaller fibres, most likely group II spindle afferent fibres
Selective trunk rehabilitative protocol in hemiparetic patients: effects on gait and functional disability
No full text
Analysis of genetic polymorphisms of cytochrome P450 2D6, adverse drug reactions and appropriate pharmacological management in bipolar patients with metabolic adverse effects
No full textConcurrent changes in shortening reaction latency and reaction time of forearm muscles in post-stroke patients.
No full textThe objective was to confirm the hypothesis that
shortening reaction (ShoRe), normally occurring on
forcibly shortening a muscle, is depressed or delayed in
post-stroke patients. Eight post-stroke patients and ten agematched
normal subjects had a 50° wrist extension or flexion
induced by a torque-motor in the affected and the nonaffected
upper limb. Patients were instructed either not to
intervene or to assist displacement (reaction-time condition,
RT). Frequency of occurrence and latency of stretch
reflex (SR) and ShoRe, and RTs were measured from the
electromyograms (EMG) of wrist flexor (FCR) and extensor
(ECR) muscles. SR had higher than normal frequency
in both muscles. ShoRe disappeared in ECR on the affected
side but had normal frequency in FCR of both sides.
ShoRe latency was prolonged in FCR and ECR, in both
affected and unaffected sides. RTs were prolonged in both
FCR and ECR, in both affected and unaffected sides.
Across all patients, RTs and ShoRe latencies in the FCR
were correlated. Neither RTs nor ShoRe latencies were correlated
to Ashworth score. RTs were inversely correlated to
Medical Research Council scores. The decreased and
delayed ShoRe in post-stroke patients supports a role for
the cortico-spinal pathway in its production or modulation.
Monitoring of ShoRe can give insight into the recovery of
the descending control of spinal reflexes
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