Echauffement et blessures : page 5.2

Le 5-HTP contre les douleurs articualires?

09/01/2016 | Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

Supplement of 5-hydroxytryptophan before induction suppresses inflammation and collagen-induced arthritis
Tao-Hsiang Yang         Arthritis Research & Therapy 2015, 17:364

Evidence is accumulating that a preclinical phase is present before the onset of clinical signs and symptoms of rheumatoid arthritis (RA). This phase represents an important therapeutic window within which interventions can dramatically modulate outcomes. An agent able to prevent RA for high risk individuals in this phase is therefore desired. In this study, we investigated whether tryptophan metabolite, 5-hydroxytryptophan (5-HTP) or 5-methoxytryptophan (5-MTP), can act as such an agent for primary prevention of collagen-induced arthritis (CIA).

Methods
Mouse splenocytes were pretreated with 5-HTP or 5-MTP and activated by anti-CD3 plus anti-CD28 antibodies in vitro. The percentages of interferon-γ (IFNγ) + CD4 + T cells and interleukin-17 (IL-17) + CD4 + T cells were measured by flow cytometry. The production of pro-inflammatory cytokines, serotonin and kynurenine was measured by enzyme-linked immunosorbent assay. A CIA model was used to investigate the in vivo effects of 5-HTP on the prevention of arthritis.

Results
5-HTP decreased the percentages of IFNγ + CD4 + T cells and IL-17 + CD4 + T cells and suppressed the production of IL-2, IL-4, IL-6, IL-17, tumor necrosis factor-α (TNFα) and IFNγ in activated splenocytes. 5-HTP administered before induction decreased the disease activities in CIA mice and suppressed the production of TNFα, IL-6 and cyclooxygenase-2 in arthritic joints. 5-HTP also increased serotonin, but decreased kynurenine in the CIA mice.

Conclusions
5-HTP suppresses inflammation and arthritis through decreasing the production of pro-inflammatory mediators. 5-HTP supplement before induction ameliorates arthritis in a CIA model.

Mal au dos: pourquoi plus de souffrance que de régénération

09/01/2016 | Echauffement et blessures et Etudes Anti-âge

 

Nerves are more abundant than blood vessels in the degenerate human intervertebral disc
Abbie L. A. Binch   Arthritis Research & Therapy 2015, 17:370

Chronic low back pain (LBP) is the most common cause of disability worldwide. New ideas surrounding LBP are emerging that are based on interactions between mechanical, biological and chemical influences on the human IVD. The degenerate IVD is proposed to be innervated by sensory nerve fibres and vascularised by blood vessels, and it is speculated to contribute to pain sensation. However, the incidence of nerve and blood vessel ingrowth, as well as whether these features are always associated, is unknown. We investigated the presence of nerves and blood vessels in the nucleus pulposus (NP) of the IVD in a large population of human discs.

Methods

Immunohistochemistry was performed with 61 human IVD samples, to identify and localise nerves (neurofilament 200 [NF200]/protein gene product 9.5) and blood vessels (CD31) within different regions of the IVD.

Results

Immunopositivity for NF200 was identified within all regions of the IVD within post-mortem tissues. Nerves were seen to protrude across lamellar ridges and through matrix towards NP cells. Nerves were identified deep within the NP and were in many cases, but not always, seen in close proximity to fissures or in areas where decreased matrix was seen. Fifteen percent of samples were degenerate and negative for nerves and blood vessels, whilst 16 % of all samples were degenerate with nerves and blood vessels. We identified 52 % of samples that were degenerate with nerves but no blood vessels. Interestingly, only 4 % ofall samples were degenerate with no nerves but positive for blood vessels. Of the 85 samples investigated, only 6 % of samples were non-degenerate without nerves and blood vessels and 7 % had nerves but no blood vessels.

Conclusions

This study addresses the controversial topic of nerve and blood vessel ingrowth into the IVD in a large number of human samples. Our findings demonstrate that nerves are present within a large proportion of NP samples from degenerate IVDs. This study shows a possible link between nerve ingrowth and degeneration of the IVD and suggests that nerves can migrate in the absence of blood vessels.

La cross-education expliquée à mes muscles

18/08/2015 | Echauffement et blessures et Etudes Musculation

 

Anodal Transcranial Direct Current Stimulation Prolongs the Cross-education of Strength and Corticomotor Plasticity
Medicine & Science in Sports & Exercise: September 2015 - Volume 47 - Issue 9 - p 1788–1797     Hendy, Ashlee M

Purpose: This study aimed to assess the efficacy of applying anodal transcranial direct-current stimulation (a-tDCS) to the ipsilateral motor cortex (iM1) during unilateral strength training to enhance the neurophysiological and functional effects of cross-education.

Methods: Twenty-four healthy volunteers were randomly allocated to perform either of the following: strength training during a-tDCS (ST + a-tDCS), strength training during sham tDCS (ST + sham), or a-tDCS during rest (a-tDCS) across 2 wk. Strength training of the right biceps brachii involved four sets of six repetitions at 80% of one-repetition maximum three times per week. Anodal tDCS was applied to the iM1 at 1.5 mA for 15 min during each strength training session. Outcome measures included one-repetition maximum strength of the untrained biceps brachii, corticomotoneuronal excitability, cross-activation, and short-interval intracortical inhibition (SICI) of the iM1 determined by transcranial magnetic stimulation.

Results: Immediately after the final training session, there was an increase in strength for both the ST + a-tDCS (12.5%, P

< 0.001) and the ST + sham group (9.4%, P = 0.007), which was accompanied by

significant increases in corticomotoneuronal excitability and decreases in SICI for both groups. After a 48-h retention period, strength increase was maintained in the ST + a-tDCS (13.0%, P = 0.001) group, which was significantly greater than the ST + sham group (7.6%, P = 0.039). Similarly, increases in corticomotoneuronal excitability and decreases in SICI were maintained in the ST + a-tDCS group but not in the ST + sham group. No main effects were reported for the a-tDCS group (all P > 0.05).

Conclusions: The addition of a-tDCS to the iM1 during unilateral strength training prolongs the benefits of cross-education, which may have significant implications to enhancement of rehabilitation outcomes after a single-limb injury or impairment.

NGF, algésie et mal au dos

22/07/2015 | Etudes sur les hormones et Echauffement et blessures et Etudes Musculation

 

Comparison of nerve growth factor–induced sensitization pattern in lumbar and tibial muscle and fascia
Benjamin Weinkauf     Muscle & Nerve Volume 2015 52, Issue 2, pages 265–272, August

Nerve growth factor (NGF) induces profound hyperalgesia
. In this study we explored patterns of NGF sensitization in muscle and fascia of distal and paraspinal sites.

Methods: We injected 1 µg of NGF into human (n = 8) tibialis anterior and erector spinae muscles and their fasciae. The spatial extent of pressure sensitization, pressure pain threshold, and mechanical hyperalgesia (150 kPa, 10 s) was assessed at days 0.25, 1, 3, 7, 14, and 21. Chemical sensitization was explored by acidic buffer injections (pH 4, 100 µl) at days 7 and 14.

Results: The mechanical hyperalgesia area was larger in tibial fascia than in muscle. Pressure pain thresholds were lower, tonic pressure pain ratings, and citrate buffer evoked pain higher in fascia than in muscle.

Conclusions: Spatial mechanical sensitization differs between muscle and fascia. Thoracolumbar fasciae appear more sensitive than tibial fasciae and may be major contributors to low back pain, but the temporal sensitization profile is similar between paraspinal and distal sites.

La leptine : un modulateur de l’activité des cellules Natural Killer ?

27/02/2015 | Echauffement et blessures et Etudes Perte de poids et Etudes Anti-âge

 

La leptine : un modulateur de l’activité des cellules Natural Killer ?
Nutrition Clinique et Métabolisme Volume 29, Issue 1, February 2015, Pages 12–25         Marie-Chantal Farges

Les cellules Natural Killer (NK) sont non seulement des effecteurs cytotoxiques de la réponse immune innée dirigée contre les cellules tumorales ou infectées mais aussi d’importants immunorégulateurs. Leur activation résulte d’une balance entre signaux inhibiteurs ou activateurs issus de multiples récepteurs. La leptine, produit par les adipocytes, est un facteur métabolique majeur qui module le système immunitaire. L’hyperleptinémie est un facteur de risque de dysimmunité et de cancer en lien, notamment, avec une moindre vigilance anti-tumorale. Cette revue fait la synthèse de la littérature traitant de l’impact de la leptine sur les cellules NK. In vitro, la leptine, en concentration similaire à celle retrouvée en situation d’obésité, stimule non seulement l’activité métabolique mais aussi l’activité lytique des cellules NK. À l’inverse, in vivo, l’hyperleptinémie associée à un régime hypercalorique ou une obésité constitutive, n’est pas corrélée à la cytotoxicité des cellules NK ce qui laisse supposer l’émergence d’une leptinorésistance.

La cryothérapie corps entier accélère t’elle la récupération très court terme?

25/02/2015 | Echauffement et blessures

 

Does whole-body cryotherapy improve vertical jump recovery following a high-intensity exercise bout?
Open Access Journal of Sports Medicine   Published Date February 2015 Volume 2015:6 Pages 49—54   Amilton Vieira

Whole-body cryotherapy (WBC) has been used as a recovery strategy following different sports activities. Thus, the aim of the study reported here was to examine the effect of WBC on vertical jump recovery following a high-intensity exercise (HIE) bout. Twelve trained men (mean ± standard deviation age = 23.9±5.9 years) were randomly exposed to two different conditions separated by 7 days: 1) WBC (3 minutes of WBC at −110°C immediately after the HIE) and 2) control (CON; no WBC after the HIE). The HIE consisted of six sets of ten repetitions of knee extensions at 60° · s−1 concentric and 180° · s−1 eccentric on an isokinetic dynamometer. The vertical jump test was used to evaluate the influence of HIE on lower extremity muscular performance. The vertical jump was performed on a force platform before HIE (T1) and 30 minutes after (T2) the WBC and CON conditions. As a result of HIE, jump height, muscle power, and maximal velocity (Vmax) had significant decreases between T1 and T2, however no significance was found between the WBC and CON conditions.

The results indicate that one session of WBC had no effect on vertical jump following an HIE compared with a CON condition. WBC may not improve muscle-function (dependent on stretch-shortening cycle) recovery in very short periods (ie, 30 minutes) following HIE.

C’est prouvé scientifiquement…

03/02/2015 | Echauffement et blessures

 

C’est prouvé scientifiquement… lorsque les femmes courent, leurs deux seins ne bougent pas de manière symétrique
Breast motion asymmetry during running
Journal of Sports Sciences Volume 33, Issue 7, 2015 pages 746-753   Chris Mills

Breast asymmetry is common in females, despite a similar driving force; dynamic activity may result in asymmetrical breast motion. This preliminary study investigated how breast categorisation (left/right or dominant/non-dominant) may affect breast support recommendations and its relationship with breast pain. Ten females ran on a treadmill at 10 kph in three breast supports (no bra, everyday bra, sports bra). Five reflective markers on the thorax and nipples were tracked using infrared cameras (200 Hz) during five running gait cycles in each breast support. Multiplanar displacements of both breasts were calculated relative to the thorax. Although the maximum individual participant difference was 2.4 cm (mediolaterally) between the left and right breast, no left/right differences were found in any direction or support condition. Notably, correlations between breast pain and anterioposterior breast displacement were stronger with the left breast (r = 0.614) and moderate with the right breast (r = 0.456). Following participant categorisation according to the greatest magnitude of superio inferior breast displacement (dominant breast), results showed significant differences in displacement for all directions across different breast supports. When using breast kinematic data to examine relationships with breast pain or to recommend breast support requirements, data on both breasts should be collected.

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