The etiology of neuromuscular fatigue induced by the 5-m shuttle run test in adult soccer players

This study investigated the etiology of neuromuscular fatigue induced by a 5-m shuttle run test (5MSRT) in soccer players. Nineteen adult male amateur soccer players (age: 20.0 ± 2.9 years) participated in the present study. Before and after the 5MSRT, they were instructed to complete a maximal voluntary isometric contraction (MVIC) of the knee extensors (KE) during and after which two electrical stimulations were applied at the femoral nerve. Voluntary activation level (VAL), surface electromyography recordings (sEMG), electrophysiological (Mmax) and potentiated resting twitch (Ptw) responses of the KE were compared between pre- and post-5MSRT. Rating of perception exertion (RPE) was also assessed before, during the test immediately following each sprint repetition and after the test. The distance covered during each sprint significantly decreased as the number of trials performed increased (p<.05). The RPE reported following each sprint significantly increased throughout the test. In addition, MVIC (-9%), sEMG (-23%), VAL (-15%), Ptw (-26%) and Mmax (~22%) of the KE were lowered from pre-to-post 5MSRT (.001 < p < .01). The 5MSRT induced a decrease of repeated-sprint running performance and MVIC of the KE. These decrements were accompanied by lowered VAL, sEMG, Ptw and Mmax values of the KE reflecting the involvement of both the central and peripheral origins in the 5MSRT-induced fatigue. Given the important muscle stress induced by 5MSRT, this strenuous test must be applied with caution, after an inevitable familiarization phase, and not during the competition period to avoid the risk of serious injury

Development of an ELISA for the detection of scorpion venoms in sera of humans envenomed by Androctonus australis garzonii (Aag) and Buthus occitanus tunetanus (Bot): correlation with clinical severity of envenoming in Tunisia.

This work was codirected by M. El Ayeb and K. Dellagi.International audienceA sandwich ELISA was set up for measuring scorpion venom levels in sera of accidentally envenomed humans with the aim to establish a quantitative relationship between these levels, envenoming severity and clinical symptoms. This assay used equine polyclonal F(ab')2, specific to two North African scorpion (Androctonus australis garzonii: Aag and Buthus occitanus tunetanus: Bot) venoms. The test proved to be simple, reproducible, very sensitive (detection limit = 0.9 ng/ml) and linear between 0.5 and 15 ng/ml of venom concentrations. A large survey on scorpion sting envenomings was conducted from 1993 to 1996 in Tunisia to gather accurate epidemiological, clinical and biological data from victims as well as informations on the treatment that they had received. Victims were classified into three grades (GI, GII and GIII) of increasing severity according to clinical signs of envenoming. Blood samples were collected from victims and tested by ELISA for their content of Aag and Bot venoms. A strong correlation was found between clinical symptoms of envenoming and the level of scorpion venom antigens in serum (r = 0.980). Mean serum venom concentrations were: 2.65 +/- 0.81 ng/ml in GI envenoming, 9.79 +/- 4.08 ng/ml in GII and 21.7 +/- 6.51 ng/ml in GIII. The difference between each group was statistically significant (p < 0.01). This ELISA may prove to be helpful to establish a rationale approach of specific antivenom therapy

Tacrolimus trough level and oxidative stress in Tunisian kidney transplanted patients

AbstractBackground The effect of tacrolimus (TAC) on oxidative stress after kidney transplantation (KT) is unclear. This study aimed to evaluate the influence of TAC trough levels of oxidative stress status in Tunisian KT patients during the post-transplantation period (PTP).Methods A prospective study including 90 KT patients was performed. TAC whole-blood concentrations were measured by the microparticle enzyme immunoassay method and adjusted according to the target range. Plasma levels of oxidants (malondialdehyde (MDA) and advanced oxidation protein products (AOPP)) and antioxidants (ascorbic acid, glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD)) were measured using spectrophotometry. The subjects were subdivided according to PTP into three groups: patients with early, intermediate, and late PT. According to the TAC level, they were subdivided into LL-TAC, NL-TAC, and HL-TAC groups.Results A decrease in MDA levels, SOD activity, and an increase in GSH levels and GPx activity were observed in patients with late PT compared to those with early and intermediate PT (p < 0.05). Patients with LL-TAC had lower MDA levels and higher GSH levels and GPx activity compared with the NL-TAC and HL-TAC groups (p < 0.05).Conclusion Our results have shown that in KT patients, despite the recovery of kidney function, the TAC reduced but did not normalize oxidative stress levels in long-term therapy, and the TAC effect significantly depends on the concentration used

The impact of a 40‐min nap on neuromuscular fatigue profile and recovery following the 5‐m shuttle run test

Summary: This study aims to investigate the impact of a 40‐min nap opportunity on perceived recovery, exertion, and maximal voluntary isometric contraction (MVIC) following the 5‐m shuttle run test (5SRT), after 1 night of normal sleep. In a randomised, counterbalanced, cross‐over design, 17 trained men (mean [SD] age 20 [3] years, height 173 [6] cm, body mass 68 [6] kg) performed a 5SRT under two conditions: a 40‐min nap opportunity and no‐nap condition. After both conditions, electromyography signals during a 5‐s isometric knee extension were recorded before and immediately after the 5SRT. Two electrical nerve stimulations at the femoral nerve were measured during and after the MVIC. Force, voluntary activation level, M‐wave amplitudes, potentiated twitch, and electromyography signals (root mean square) were measured during each MVIC. Perceived exertion was recorded after each repetition of the test and perceived recovery was determined after the end of the MVIC. Compared to the no‐nap condition, the 40‐min nap resulted in significant enhancements in both the highest distance (p < 0.01, Δ = +7.6%) and total distance (p < 0.01, Δ = +7.5%). Before and after exercise, values for MVIC, root mean square, M‐wave amplitudes, and voluntary activation level were improved after the 40‐min nap opportunity compared to no‐nap condition (all p ≤ 0.01). Values for perceived exertion and recovery were improved after the 40‐min nap opportunity in comparison with no‐nap condition (p ≤ 0.01). A 40‐min nap opportunity improved repeated high‐intensity short‐term maximal performance, perceived recovery, associated neuromuscular responses, and reduced perceived fatigue. Therefore, our findings suggest that central and peripheral processes are involved in the improvements of 5SRT performance after napping.</p

A Founder Large Deletion Mutation in Xeroderma Pigmentosum-Variant Form in Tunisia: Implication for Molecular Diagnosis and Therapy

Xeroderma pigmentosum Variant (XP-V) form is characterized by a late onset of skin symptoms. Our aim is the clinical and genetic investigations of XP-V Tunisian patients in order to develop a simple tool for early diagnosis. We investigated 16 suspected XP patients belonging to ten consanguineous families. Analysis of the POLH gene was performed by linkage analysis, long range PCR, and sequencing. Genetic analysis showed linkage to the POLH gene with a founder haplotype in all affected patients. Long range PCR of exon 9 to exon 11 showed a 3926 bp deletion compared to control individuals. Sequence analysis demonstrates that this deletion has occurred between two Alu-Sq2 repetitive sequences in the same orientation, respectively, in introns 9 and 10. We suggest that this mutation POLH NG_009252.1: g.36847_40771del3925 is caused by an equal crossover event that occurred between two homologous chromosomes at meiosis. These results allowed us to develop a simple test based on a simple PCR in order to screen suspected XP-V patients. In Tunisia, the prevalence of XP-V group seems to be underestimated and clinical diagnosis is usually later. Cascade screening of this founder mutation by PCR in regions with high frequency of XP provides a rapid and cost-effective tool for early diagnosis of XP-V in Tunisia and North Africa