833 resultados para Flexor Muscles
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The aim of this study was to evaluate the influence of oral contraceptive use on the silent period (SP) of anterior temporal and masseter muscles during the menstrual cycle. Totally, 28 women on reproductive age were selected including 15 nonusers of any hormone and 13 contraceptive users. All patients were dentate without muscular temporomandibular disorders. Electromyography (SP test) of the anterior temporal and masseter muscles was conducted every week during three consecutive menstrual cycles at 1(st) day of menstruation (P1), 7(th) day (P2), 14(th) day (P3) and 21(st) day (P4). The SP values in the anterior temporal and masseter muscles were measured at both sides. The SP values of the right side (13.49 ms) at P2 were significantly different compared to the left side (12.28 ms). However, there was no significant difference on the interactions among the three factors. It can be concluded that the SP values in healthy women in reproductive age may not be influenced by the menstrual cycle with similar results for both muscles.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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To analyze strength and integrated electromyography (IEMG) data in order to determine the neuromuscular efficiency (NME) of the vastus lateralis (VL) and biceps femoris (BF) muscles in patients with anterior cruciate ligament (ACL) injuries, during the preoperative and postoperative periods; and to compare the injured limb at these two times, using the non-operated limb as a control. EMG data and BF and VL strength data were collected during three maximum isometric contractions in knee flexion and extension movements. The assessment protocol was applied before the operation and two months after the operation, and the NME of the BF and VL muscles was obtained. There was no difference in the NME of the VL muscle from before to after the operation. On the other hand, the NME of the BF in the non-operated limb was found to have increased, two months after the surgery. The NME provides a good estimate of muscle function because it is directly related to muscle strength and capacity for activation. However, the results indicated that two months after the ACL reconstruction procedure, at the time when loading in the open kinetic chain within rehabilitation protocols is usually started, the neuromuscular efficiency of the VL and BF had still not been reestablished.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of this study was to verify the effects of running overtraining protocols performed in downhill, uphill, and without inclination on the proteins related to hypertrophy signaling pathway in extensor digitorum longus (EDL) and soleus of C57BL/6 mice. We also performed histological and stereological analyses. Rodents were divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR). The incremental load, exhaustive, and grip force tests were used as performance evaluation parameters. 36 h after the grip force test, EDL and soleus were removed and immediately used for immunoblotting analysis or stored at -80°C for histological and stereological analyses. For EDL, OTR/down decreased the protein kinase B (Akt) and tuberous sclerosis protein 2 (TSC2) phosphorylation (p), and increased myostatin, receptor-activated Smads (pSMAD2-3), and insulin receptor substrate-1 (pIRS-1; Ser307/636). OTR/down also presented low and high relative proportions of cytoplasm and connective tissue, respectively. OTR/up increased the mammalian target of rapamycin (pmTOR), 70-kDa ribosomal protein S6 kinase 1 (pS6K1) and pSMAD2-3, and decreased pTSC2. OTR decreased pTSC2 and increased pIRS-1 (Ser636). For soleus, OTR/down increased S6 ribosomal protein (pS6RP) and pSMAD2-3, and decreased pIRS-1 (Ser639). OTR/up decreased pS6K1, pS6RP and pIRS-1 (Ser639), and increased pTSC2 (Ser939), and pSMAD2-3. OTR increased pS6RP, 4E-binding protein-1 (p4E-BP1), pTSC2 (Ser939), and pSMAD2-3, and decreased pIRS-1 (Ser639). In summary, OTR/down inhibited the skeletal muscle hypertrophy with concomitant signs of atrophy in EDL. The effects of OTR/up and OTR depended on the analyzed skeletal muscle type. J. Cell. Physiol. 9999: 1-12, 2015. © 2015 Wiley Periodicals, Inc.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The purpose of this study was to investigate the effects of the superficial digital tenotomy and the superior check ligament desmotomy on the radio-metacarpal, metacarpophalangeal, proximal and distal interphalangeal angles in horses. Under general anesthesia the superficial digital flexor tenotomy and superior check ligament desmotomy were performed, respectively, on the right and left forelimbs in nine horses. Before surgery and on 15th, 30th, and 60th postoperative days the radio-metacarpal, metacarpophalangeal, and proximal and distal interphalangeal angles were measured by radiographic examination. Tenotomy decreased significantly the metacarpophalangeal angle (mean ± standard deviation: preoperative – 140.7º ± 6.85; 60th day – 128.2º ± 5.93) and increased the distal interphalangeal angle (mean ± standard deviation: preoperative – 172.6 ± 1.87; 60th day – 167.6 ± 1.36). Desmotomy decreased the proximal interphalangeal angle (mean ± standard deviation: preoperative – 180.2º ± 5.43; 60th day- 197.3º ± 8.29). These surgical procedures did not change the radio-metacarpal angle. The superficial digital flexor tenotomy and the superior check ligament desmotomy cause different and significant changes in joint angles distal to the carpus.
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Objective: To analyze the effects of a water-based exercise program on peak torque (PT) and rate of torque development (RTD) during maximal voluntary ballistic isometric contractions of the lower limb muscles and the performance of a number of functional tests in the elderly. Method: Thirty-seven elderly were randomly assigned to water-based training (3 d/wk for 12 wk) or a control group. Extensor and flexor PT and RTD of the ankle, knee, and hip joints and functional tests were evaluated before and after training. Results: PT increased after training for the hip flexors (18%) and extensors (40%) and the plantar-flexor (42%) muscles in the water-based group. RTD increased after training for the hip-extensor (10%), knee-extensor (11%), and ankle plantar-flexor (27%) muscles in the water-based group. Functional tests also improved after training in the water-based group (p < .05). Conclusion: The water-based program improved PT and RTD and functional performance in the elderly.
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This study evaluated the effects of two lipids sources of fish residue (tilapia and salmon) compared with a vegetable oil source (soybean oil) on the fatty acid profiles of male and female lambari. This experiment was developed in a completely randomized experimental design in a 3 x 2 factorial arrangement, totaling 6 treatments resulting from the combination of the three experimental diets for both sexes, with four replications for each treatment. This study involved 120 male (2.58 +/- 0.13 g) and 72 female lambari (4.00 +/- 0.09 g), fed the experimental diets twice a day until apparent satiation for a period of 60 days. Oleic, linoleic, palmitic and stearic fatty acids were found at higher concentrations in all experimental oils and diets, as well in the muscle of male and female lambari. The low amounts of arachidonic, eicosapentaenoic and docosahexaenoic acids in the experimental diets and subsequent greater concentrations in muscle tissue, suggested that lambari are able to desaturate and elongate the chain of fatty acids with 18 carbons. The fish of both sexes that received the diet with soybean oil showed high levels of n-6 fatty acids, especially of C18: 2n-6 and low levels of eicosapentaenoic and docosahexaenoic acids. The diet with salmon residue oil promoted higher levels of fatty acids of the n-3 series and resulted in the best n-3/n-6 ratio in the muscle of male and female lambari. The oils from fish residues can be a substitute for traditional fish oil and its use in the lambari diets does not impair its growth.
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Heat shock proteins play a key regulatory role in cellular defense. To investigate the role of the inducible 70-kDa heat shock protein (HSP70) in skeletal muscle atrophy and subsequent recovery, soleus (SOL) and extensor digitorum longus (EDL) muscles from overexpressing HSP70 transgenic mice were immobilized for 7 days and subsequently released from immobilization and evaluated after 7 days. Histological analysis showed that there was a decrease in cross-sectional area of type II myofiber from EDL and types I and II myofiber from SOL muscles at 7-day immobilization in both wild-type and HSP70 mice. At 7-day recovery, EDL and SOL myofibers from HSP70 mice, but not from wild-type mice, recovered their size. Muscle tetanic contraction decreased only in SOL muscles from wild-type mice at both 7-day immobilization and 7-day recovery; however, it was unaltered in the respective groups from HSP70 mice. Although no effect in a fatigue protocol was observed among groups, we noticed a better contractile performance of EDL muscles from overexpressing HSP70 groups as compared to their matched wild-type groups. The number of NCAM positive-satellite cells reduced after immobilization and recovery in both EDL and SOL muscles from wild-type mice, but it was unchanged in the muscles from HSP70 mice. These results suggest that HSP70 improves structural and functional recovery of skeletal muscle after disuse atrophy, and this effect might be associated with preservation of satellite cell amount.
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Objective: To test the hypothesis that the extraocular muscles (EOMs) of patients with infantile nystagmus have muscular and innervational adaptations that may have a role in the involuntary oscillations of the eyes. Methods: Specimens of EOMs from 10 patients with infantile nystagmus and postmortem specimens from 10 control subjects were prepared for histologic examination. The following variables were quantified: mean myofiber cross-sectional area, myofiber central nucleation, myelinated nerve density, nerve fiber density, and neuromuscular junction density. Results: In contrast to control EOMs, infantile nystagmus EOMs had significantly more centrally nucleated myofibers, consistent with cycles of degeneration and regeneration. The EOMs of patients with nystagmus also had a greater degree of heterogeneity in myofiber size than did those of controls, with no difference in mean myofiber cross-sectional area. Mean myelinated nerve density, nerve fiber density, and neuromuscular junction density were also significantly decreased in infantile nystagmus EOMs. Conclusions: The EOMs of patients with infantile nystagmus displayed a distinct hypoinnervated phenotype. This represents the first quantification of changes in central nucleation and myofiber size heterogeneity, as well as decreased myelinated nerve, nerve fiber, and neuromuscular junction density. These results suggest that deficits in motor innervation are a potential basis for the primary loss of motor control.
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Background: Evidence of self-sustained muscle activation following a brief electrical stimulation has been reported in the literature for certain muscles. Objectives: This report shows that the foot muscle (Flexor Digitorum Brevis - FDB) shows a self-sustained increase in muscle activity during upright stance in some subjects following a train of stimuli to the tibial nerve. Methods: Healthy subjects were requested to stand upright and surface EMG electrodes were placed on the FDB, Soleus and Tibialis Anterior muscles. After background muscle activity (BGA) acquisition, a 50 Hz train of stimuli was applied to the tibial nerve at the popliteal fossa. The root mean square values (RMS) of the BGA and the post-stimulus muscle activation were computed. Results: There was a 13.8% average increase in the FDB muscle EMG amplitude with respect to BGA after the stimulation was turned off. The corresponding post-stimulus Soleus EMG activity decreased by an average of 9.2%. We hypothesize that the sustained contraction observed in the FDB following stimulus may be evidence of persistent inward currents (PIC) generated in FDB spinal motoneurons. The post-stimulus decrease in soleus activity may have occurred due to the action of inhibitory interneurons caused by the PICs, which were triggered by the stimulus train. Conclusions: These sustained post-stimulation changes in postural muscle activity, found in different levels in different subjects, may be part of a set of possible responses that contribute to overall postural control.
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Goncalves DA, Silveira WA, Lira EC, Gra a FA, Paula-Gomes S, Zanon NM, Kettelhut IC, Navegantes LC. Clenbuterol suppresses proteasomal and lysosomal proteolysis and atrophy-related genes in denervated rat soleus muscles independently of Akt. Am J Physiol Endocrinol Metab 302: E123-E133, 2012. First published September 27, 2011; doi:10.1152/ajpendo.00188.2011.-Although it is well known that administration of the selective beta(2)-adrenergic agonist clenbuterol (CB) protects muscle following denervation (DEN), the underlying molecular mechanism remains unclear. We report that in vivo treatment with CB (3 mg/kg sc) for 3 days induces antiproteolytic effects in normal and denervated rat soleus muscle via distinct mechanisms. In normal soleus muscle, CB treatment stimulates protein synthesis, inhibits Ca(2+)-dependent proteolysis, and increases the levels of calpastatin protein. On the other hand, the administration of CB to DEN rats ameliorates the loss of muscle mass, enhances the rate of protein synthesis, attenuates hyperactivation of proteasomal and lysosomal proteolysis, and suppresses the transcription of the lysosomal protease cathepsin L and of atrogin-1/MAFbx and MuRF1, two ubiquitin (Ub) ligases involved in muscle atrophy. These effects were not associated with alterations in either IGF-I content or Akt phosphorylation levels. In isolated muscles, CB (10(-6) M) treatment significantly attenuated DEN-induced overall proteolysis and upregulation in the mRNA levels of the Ub ligases. Similar responses were observed in denervated muscles exposed to 6-BNZ-cAMP (500 mu M), a PKA activator. The in vitro addition of triciribine (10 mu M), a selective Akt inhibitor, did not block the inhibitory effects of CB on proteolysis and Ub ligase mRNA levels. These data indicate that short-term treatment with CB mitigates DEN-induced atrophy of the soleus muscle through the stimulation of protein synthesis, downregulation of cathepsin L and Ub ligases, and consequent inhibition of lysosomal and proteasomal activities and that these effects are independent of Akt and possibly mediated by the cAMP/PKA signaling pathway.
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BALDON, R. D. M., D. F. M. LOBATO, L. P. CARVALHO, P. Y. L. WUN, P. R. P. SANTIAGO, and F. V. SERRAO. Effect of Functional Stabilization Training on Lower Limb Biomechanics in Women. Med. Sci. Sports Exerc., Vol. 44, No. 1, pp. 135-145, 2012. Purpose: This study aimed to verify the effects of functional stabilization training on lower limb kinematics, functional performance, and eccentric hip and knee torques. Methods: Twenty-eight women were divided into a training group (TG; n = 14), which carried out the functional stabilization training during 8 wk, and a control group (CG; n = 14), which carried out no physical training. The kinematic assessment of the lower limb was performed during a single-leg squat, and the functional performance was evaluated by way of the single-leg triple hop and the timed 6-m single-leg hop tests. The eccentric hip abductor, adductor, lateral rotator, medial rotator, and the knee flexor and extensor torques were measured using an isokinetic dynamometer. Results: After 8 wk, the TG significantly reduced the values for knee abduction (from -6.86 degrees to 1.49 degrees), pelvis depression (from -10.21 degrees to -7.86 degrees) and femur adduction (from 7.08 degrees to 5.19 degrees) as well as increasing the excursion of femur lateral rotation (from -0.55 degrees to -3.67 degrees). Similarly, the TG significantly increased the values of single-leg triple hop (from 3.52 to 3.92 m) and significantly decreased the values of timed 6-m single-leg hop tests (from 2.43 to 2.14 s). Finally, the TG significantly increased the eccentric hip abductor (from 1.31 to 1.45 N center dot m center dot kg(-1)), hip lateral rotator (from 0.75 to 0.91 N center dot m center dot kg(-1)), hip medial rotator (from 1.45 to 1.66 N center dot m center dot kg(-1)), knee flexor (from 1.43 to 1.55 N center dot m center dot kg(-1)), and knee extensor (from 3.46 to 4.40 N center dot m center dot kg(-1)) torques. Conclusions: Strengthening of the hip abductor and lateral rotator muscles associated with functional training improves dynamic lower limb alignment and increases the strength and functional performance.
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Pieri N.C.G., Alicia M. Flamini A.M., Barbeito C.G., Casals J.B., Roque K.B., Favaron P.O., Miglino M.A. & Martins D.S. 2012. [Shape and function of the perineal muscles of viscacha (Lagostomus maximus).] Forma e funcao dos musculos perineais da viscacha (Lagostomus maximus). Pesquisa Veterinaria Brasileira 32(2):183-187. Departamento de Zootecnia, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de Sao Paulo, Av. Duque de Caxias Norte 225, Pirassununga, SP 13635-900, Brazil. E-mail: daniele@usp.br. Among the rodent species studied we can highlight the wide variation in the morphology of the male reproductive system. Thus, considering the ecological importance of rodents, and the large number and geographical representation of this animal, as well as shortages regarding the reproductive anatomy, we developed this study with viscacha, a South American histricomorph rodent. As this species has some very peculiar reproductive features, we described the gross anatomy of the perineal muscles and the role of copulatory behavior. The perineal region of viscacha is composed of five muscles, three of which are arranged in the superficial genitourinary diaphragm, as Musculus ischiocavernosus, M. bulbocavernosus and M. bulbospongiosus, and the muscles that lie at the pelvic diaphragm, M. levator ani and M. retractor penis. Therefore, we emphasize that the study of the pelvic floor in wild animals is of great value, then contribute to a better understanding of the mechanisms related to erection and ejaculation or collaborate with studies on the reproduction of animals.