Improved tolerance of peripheral fatigue by the central nervous system after endurance training.

PURPOSE: The purposes of this study were to evaluate the effect of endurance training on central fatigue development and recovery. METHODS: A control group was compared to a training group, which followed an 8-week endurance-training program, consisting in low-force concentric and isometric contractions. Before (PRE) and after (POST) the training period, neuromuscular function of the knee extensor (KE) muscles was evaluated before, immediately after and during 33 min after an exhausting submaximal isometric task at 15 % of the maximal voluntary contraction (MVC) force. After training, the trained group performed another test at iso-time, i.e., with the task maintained until the duration completed before training was matched (POST2). The evaluation of neuromuscular function consisted in the determination of the voluntary activation level during MVCs, from peripheral nerve electrical (VAPNS) and transcranial magnetic stimulations (VATMS). The amplitude of the potentiated twitch (Pt), the evoked [motor evoked potentials, cortical silent period (CSP)] and voluntary EMG activities were also recorded on the KE muscles. RESULTS: Before training, the isometric task induced significant reductions of VAPNS, VATMS and Pt, and an increased CSP. The training period induced a threefold increase of exercise duration, delayed central fatigue appearance, as illustrated by the absence of modification of VAPNS, VATMS and CSP after POST2. At POST, central fatigue magnitude and recovery were not modified but Pt reduction was greater. CONCLUSION: These results suggest that central fatigue partially adapts to endurance training. This adaptation principally translates into improved tolerance of peripheral fatigue by the central nervous system.

Reducing resistance training volume during Ramadan improves muscle strength and power in football players.

We aimed to examine the effect of maintaining or reducing resistance training volume during Ramadan-intermittent-fasting (RIF) on short-term maximal performances. 20 footballers (age: 18.4 ± 0.8 years; body-mass: 72.4 ± 4.1 kg; height: 183.4 ± 4.6 cm) were matched and randomly assigned to a normal-training-group (G1) or a tapering-group (G2). They were tested for muscular strength (maximal-voluntary-contraction) and power (squat-jump and counter-movement-jump) 1 month before RIF (T0), 1 week before RIF (T1), after 2 weeks of fasting (T2) and at the end of RIF (T3). From T1 to T2, subjects performed a whole-body resistance training program (8-repetitions × 4-sets with 4-min recovery in-between). During RIF, G1 maintained the same training program, while G2 performed a period of reduced training volume (3 sets/exercise; - 22%). Muscle strength and power increased significantly from T0 to T1, from T0 to T2 and from T0 to T3 in G1 and G2 and from T1 to T2 and from T1 to T3 only in G2 (p<0.05). Performance was higher in G2 than G1 during T2 (p<0.01). Moreover, the ∆-change of performance between T0 and T2 and T3 was significantly higher in G2 than G1 (p<0.05). For young soccer players, a tapering period characterized by a reduced training volume during RIF may lead to significant improvement in muscle strength and power.

Time of day effects on repeated sprint ability.

The present study aimed at investigating the effects of time-of-day on muscle power and associated electromyographic (EMG) activity level of 4 thigh muscles during a repeated pedalling sprint exercise. After a familiarization session, 12 male subjects were asked to perform the repeated sprint ability test during 2 experimental sessions (randomized order), which were set up either at 06:00 or 18:00 h. For each sprint, peak power output, percentage of peak power decrement and total work were calculated. EMG activity of vastus lateralis, rectus femoris, vastus medialis and biceps femoris muscles was recorded throughout the test and analyzed for each sprint. Total work and percentage of peak power decrement were higher in the evening than in the morning (p<0.01 and p<0.05, respectively). Likewise, peak power was significantly higher at 18:00 than 06:00 h during the first 3 sprints (p<0.01 for sprint 1 and p<0.05 for sprint 2 and 3). There was no time-of-day effect for EMG activity level. The neuromuscular efficiency decreased significantly over the repeated sprint ability test at the 2 times of testing (p<0.01). Despite diurnal fluctuation in muscular power and neuromuscular fatigue during the repeated sprint ability test, EMG activity of major thigh muscles was not time-of-day dependent.

Dimorphism of TAP-1 gene in Caucasian with juvenile myoclonic epilepsy and in Tunisian with idiopathic generalized epilepsies.

Juvenile myoclonic epilepsy (JME) is the most common form of idiopathic generalized epilepsies (IGE) that account for about 5-10% of all types of epilepsies. The first putative locus termed EJM1 is on the human leucocyte antigen (HLA-II) region of chromosome 6p21.3. Interestingly, the EJM1 region includes the Transporter associated with antigen processing 1 (TAP-1) gene encoding the TAP-1, and previous studies have reported associations between HLA-II polymorphisms and different types of epilepsy. In this study, we report an association between two TAP-1 functional polymorphisms the I333V and the D637G and most common IGE in Tunisian population, but we fail to find significant results in Caucasian with JME.

[Peripheral neuropathy induced by acute methyl bromide skin exposure: a case report]. / Neuropathie périphérique par intoxication aiguë au bromure de méthyle: à propos d'une observation.

INTRODUCTION: Methyl bromide is a pesticide used as a fumigating agent in homes, for food storage and soil disinfection. Chronic and acute exposures to methyl bromide are known to cause damage to the central and peripheral nervous system. OBSERVATION: We describe a case of a 31-year-old patient who developed a peripheral neuropathy due to an acute exposure on skin of methyl bromide. This patient was admitted after an accidental dermal exposure to methyl bromide while fumigating dates. The patient suffered dermal burns and vesicles on the upper limbs. Two weeks following exposure, she developed weakness of the lower and upper limbs, ataxia, paresthesiae of both legs and arms, abolition of tendon reflexes in the upper and lower limbs and Babinski sign. An axonal neuropathy was detected at the electrophysiological study. The patient recovered gradually. CONCLUSION: While cases of methyl bromide are rare, this study illustrates the toxic effect on the peripheral nervous system.

[Reversible peripheral neuropathy induced by vitamin B12 deficiency]. / Neuropathie périphérique réversible liée au déficit en vitamine B12.

OBJECTIVE: To describe an electroclinical presentation of a peripheral neuropathy in a patient who suffered from vitamin B12 deficiency. PATIENT AND METHODS: We report the case of a 56-year-old man who, 17 years after a subtotal gastrectomy, presented with a diffuse sensory-motor demyelinating peripheral neuropathy with multifocal alteration of conduction confirmed by electromyography. Its causal relationship with vitamin B12 deficiency was biologically demonstrated. This neuropathy improved within a few days after intramuscular hydroxocobalamin treatment. Both clinical and electrophysiological signs had totally disappeared 3 months later on. CONCLUSION: This observation demonstrates that, in spite of its poor outcome reported by several authors, peripheral neuropathy induced by vitamin B12 deficiency can recover completely with substitutive treatment.

[Acute repetitive giratory seizures as a manifestation of nonketotic hyperglycemia]. / Crises giratoires répétitives révélatrices d'une hyperglycémie non cétosique.

This 71 years old women without any history of epilepsy had diabetes mellitus. She was admitted for repetitive giratory seizures in relation with non-ketotic hyperglycaemia. The EEG showed right centro-parietal paroxysmal slow activity. Symptomatology disappeared within 48 hours after insulin therapy. One month later, she presented with a left hemiplegia in relation with a right sylvian infraction. The role of focal transitory ischaemia in connection with hyperglycaemia is discussed.

[Antiparkinson drugs in neuroleptic treatment: comparative study of progressive and abrupt withdrawal]. / Les antiparkinsoniens au cours du traitement neuroleptique: étude comparative des modes de sevrage progressif et brutal.

The systematic and long term association of anti-parkinsonian drugs to neuroleptics is questioned by many authors because of their side effects and their toxicomanogenous risks whereas their efficiency in extrapyramidal effects of prophylaxis is not certain. This work aims at evaluating the interest of prescribing long term parkinsonian drug in association with neuroleptics. The study centered on 101 psychotic patients treated with neuroleptics, and followed on an ambulatory bases. 97% of this patients systematically received antiparkinsonian drugs. Extrapyramidal symptoms of varied intensity have noted for 61% of patients. The authors have compared, in double blind, the effects of the progressive and abrupt withdrawal of anti-parkinsonian drugs for 37 patients among the 101. These patients have been regularly treated for at least 6 months by neuroleptics (fluphenazine or pipothiazine) in association with trihexyphenidyle. They were randomly divided into 3 groups, and statified by sex and type of neuroleptic. For group I, composed of 13 patients, trihexyphenidyle is abruptly withdrawn and replaced by a placebo. For group II, composed of 11 patients, withdrawal is progressive for 2 weeks, trihexyphenidyle being replaced by a placebo. Group III, composed of 13 patients, is a sample group which went on receiving trihexyphenidyle. The results of this study showed that within the brutal withdrawal group (group I), 10 patients over 13 needed trihexyphenidyle again, whereas only 3 patients over 11 needed it in the progressive withdrawal group (group II). In the sample group (group III), one patient over 13 showed extrapyramidal symptoms, necessitating his leaving school. The global chi 2 is significant with p < 0.001.(ABSTRACT TRUNCATED AT 250 WORDS)

[Trigeminal somatosensory evoked potentials in workers handling trichloroethylene]. / Potentiels évoqués somesthésiques du trijumeau chez des travailleurs manipulant le trichloréthyléne.

Trigeminal somatosensory evoked potentials (TSEP) were studied in 33 workers manipulating trichlorethylene for 3 to 22 years and in 33 control subjects. A significant excessive latency delay of N13, P17 and N45 waves in workers was found. Evoked potential abnormalities found in 15 exposed subjects (45%) were as following: excessive latency delay in 9 cases (27%), decrease of amplitude in 2 cases (6%) and asymmetrical responses in 4 cases (12%). Among 5 workers (15%) presenting clinical abnormalities of trigeminal nerve impairment, only one had normal evoked potential. TSEP were altered in 11 workers (33%) who had no clinical impairment. We suggest that TSEP should be confirm trigeminal impairment in chronic cases of workers exposed to carbon tetrachloride and to predict infraclinic lesions.