Fit-climbing test: a field test for indoor rock climbing

Bertuzzi, R, Franchini, E, Tricoli, V, Lima-Silva, AE, Pires, FDO, Okuno, NM, and Kiss, MAPDM. Fit-climbing test: A field test for indoor rock climbing. J Strength Cond Res 26(6): 1558-1563, 2012-The aim of this study was to develop an indoor rock-climbing test on an artificial wall (Fit-climbing test). Thirteen climbers (elite group [EG] = 6; recreational group [RG] = 7) performed the following tests: (a) familiarization in the Fitclimbing test, (b) the Fit-climbing test, and (c) a retest to evaluate the Fit-climbing test's reliability. Gas exchange, blood lactate concentration, handgrip strength, and heart rate were measured during the test. Oxygen uptake during the Fit-climbing test was not different between groups (EG = 8.4 +/- 1.1 L; RG = 7.9 +/- 1.5 L, p > 0.05). The EG performance (120 +/- 7 movements) was statistically higher than the RG climbers' performance (78 +/- 13 movements) during the Fit-climbing test. Consequently, the oxygen cost per movement during the Fit-climbing test of the EG was significantly lower than that of the RG (p < 0.05). Handgrip strength was higher in the EG when compared with that in the RG in both pre-Fit- and post-Fit-climbing test (p < 0.05). There were no significant differences in any other variables analyzed during the Fit-climbing test (p > 0.05). Furthermore, the performance in the Fit-climbing test presented high reliability (intraclass correlation coefficient = 0.97). Therefore, the performance during the Fit-climbing test may be an alternative to evaluate rock climbers because of its specificity and relation to oxygen cost per movement during climbing.

Changes in hippocampal gene expression by 7-nitroindazole in rats submitted to forced swimming stress

Nitric oxide (NO) is an atypical neurotransmitter that has been related to the pathophysiology of major depression disorder. Increased plasma NO levels have been reported in depressed and suicidal patients. Inhibition of neuronial nitric oxide synthase (nNOS), on the other hand, induces antidepressant effects in clinical and pre-clinical trials. The mechanisms responsible for the antidepressant-like effects of nNOS inhibitors, however, are not completely understood. In this study, genomic and proteomic analyses were used to investigate the effects of the preferential nNOS inhibitor 7-nitroindazole (7-NI) on changes in global gene and protein expression in the hippocampus of rats submitted to forced swimming test (FST). Chronic treatment (14 days, i.p.) with imipramine (15 mg/kg daily) or 7-NI (60 mg/kg daily) significantly reduced immobility in the FST. Saturation curves for Serial analysis of gene expression libraries showed that the hippocampus of animals submitted to FST presented a lower number of expressed genes compared to non-FST stressed groups. Imipramine, but not 7-NI, reverted this effect. GeneGo analyses revealed that genes related to oxidative phosphorylation, apoptosis and survival controlled by HTR1A signaling and cytoskeleton remodeling controlled by Rho GTPases were significantly changed by FST. 7-NI prevented this effect. In addition, 7-NI treatment changed the expression of genes related to transcription in the cAMP response element-binding pathway. Therefore, this study suggests that changes in oxidative stress and neuroplastic processes could be involved in the antidepressant-like effects induced by nNOS inhibition.

Swimming Training in Rats Increases Cardiac MicroRNA-126 Expression and Angiogenesis

DA SILVA, N. D. JR, T. FERNANDES, U. P. R. SOCI, A. W. A. MONTEIRO, M. I. PHILLIPS, and E. M. DE OLIVEIRA. Swimming Training in Rats Increases Cardiac MicroRNA-126 Expression and Angiogenesis. Med. Sci. Sports Exerc., Vol. 44, No. 8, pp. 1453-1462, 2012. Purpose: MicroRNA (miRNA)-126 is angiogenic and has two validated targets: Sprouty-related protein 1 (Spred-1) and phosphoinositol-3 kinase regulatory subunit 2 (PI3KR2), negative regulators of angiogenesis by VEGF pathway inhibition. We investigated the role of swimming training on cardiac miRNA-126 expression related to angiogenesis. Methods: Female Wistar rats were assigned to three groups: sedentary (S), training 1 (T1, moderate volume), and training 2 (T2, high volume). T1 consisted of 60 min.d(-1) of swimming, five times per week for 10 wk with 5% body overload. T2 consisted of the same protocol of T1 until the eighth week; in the ninth week, rats trained for two times a day, and in the 10th week, rats trained for three times a day. MiRNA and PI3KR2 gene expression analysis was performed by real-time polymerase chain reaction in heart muscle. We assessed markers of training, the cardiac capillary-fiber ratio, cardiac protein expression of VEGF, Spred-1, Raf-1/ERK 1/2, and PI3K/Akt/eNOS. Results: The cardiac capillary-fiber ratio increased in T1 (58%) and T2 (101%) compared with S. VEGF protein expression was increased 42% in T1 and 108% in T2. Cardiac miRNA-126 expression increased 26% (T1) and 42% (T2) compared with S, correlated with angiogenesis. The miRNA-126 target Spred-1 protein level decreased 41% (T1) and 39% (T2), which consequently favored an increase in angiogenic signaling pathway Raf-1/ERK 1/2. On the other hand, the gene expression of PI3KR2, the other miRNA-126 target, was reduced 39% (T1) and 78% (T2), and there was an increase in protein expression of components of the PI3K/Akt/eNOS signaling pathway in the trained groups. Conclusions: This study showed that aerobic training promotes an increase in the expression of miRNA-126 and that this may be related to exercise-induced cardiac angiogenesis, by indirect regulation of the VEGF pathway and direct regulation of its targets that converged in an increase in angiogenic pathways, such as MAPK and PI3K/Akt/eNOS.

Models of passive and active dendrite motoneuron pools and their differences in muscle force control

Motoneuron (MN) dendrites may be changed from a passive to an active state by increasing the levels of spinal cord neuromodulators, which activate persistent inward currents (PICs). These exert a powerful influence on MN behavior and modify the motor control both in normal and pathological conditions. Motoneuronal PICs are believed to induce nonlinear phenomena such as the genesis of extra torque and torque hysteresis in response to percutaneous electrical stimulation or tendon vibration in humans. An existing large-scale neuromuscular simulator was expanded to include MN models that have a capability to change their dynamic behaviors depending on the neuromodulation level. The simulation results indicated that the variability (standard deviation) of a maintained force depended on the level of neuromodulatory activity. A force with lower variability was obtained when the motoneuronal network was under a strong influence of PICs, suggesting a functional role in postural and precision tasks. In an additional set of simulations when PICs were active in the dendrites of the MN models, the results successfully reproduced experimental results reported from humans. Extra torque was evoked by the self-sustained discharge of spinal MNs, whereas differences in recruitment and de-recruitment levels of the MNs were the main reason behind torque and electromyogram (EMG) hysteresis. Finally, simulations were also used to study the influence of inhibitory inputs on a MN pool that was under the effect of PICs. The results showed that inhibition was of great importance in the production of a phasic force, requiring a reduced co-contraction of agonist and antagonist muscles. These results show the richness of functionally relevant behaviors that can arise from a MN pool under the action of PICs.

Mechanical Alterations in airway smooth muscle after interaction with indoor pollutant – A mathematical model.

The viscoelasticity of mammalian lung is determined by the mechanical properties and structural regulation of the airway smooth muscle (ASM). The exposure to polluted air may deteriorate these properties with harmful consequences to individual health. Formaldehyde (FA) is an important indoor pollutant found among volatile organic compounds. This pollutant permeates through the smooth muscle tissue forming covalent bonds between proteins in the extracellular matrix and intracellular protein structure changing mechanical properties of ASM and inducing asthma symptoms, such as airway hyperresponsiveness, even at low concentrations. In the experimental scenario, the mechanical effect of FA is the stiffening of the tissue, but the mechanism behind this effect is not fully understood. Thus, the aim of this study is to reproduce the mechanical behavior of the ASM, such as contraction and stretching, under FA action or not. For this, it was created a two-dimensional viscoelastic network model based on Voronoi tessellation solved using Runge-Kutta method of fourth order. The equilibrium configuration was reached when the forces in different parts of the network were equal. This model simulates the mechanical behavior of ASM through of a network of dashpots and springs. This dashpot-spring mechanical coupling mimics the composition of the actomyosin machinery of ASM through the contraction of springs to a minimum length. We hypothesized that formation of covalent bonds, due to the FA action, can be represented in the model by a simple change in the elastic constant of the springs, while the action of methacholine (MCh) reduce the equilibrium length of the spring. A sigmoid curve of tension as a function of MCh doses was obtained, showing increased tension when the muscle strip was exposed to FA. Our simulations suggest that FA, at a concentration of 0.1 ppm, can affect the elastic properties of the smooth muscle ¯bers by a factor of 120%. We also analyze the dynamic mechanical properties, observing the viscous and elastic behavior of the network. Finally, the proposed model, although simple, incorporates the phenomenology of both MCh and FA and reproduces experimental results observed with in vitro exposure of smooth muscle to FA. Thus, this new mechanical approach incorporates several well know features of the contractile system of the cells in a tissue level model. The model can also be used in different biological scales.

Mechanical alterations in airway smooth muscle after interaction with indoor pollutant - A mathematical model

The viscoelasticity of mammalian lung is determined by the mechanical properties and structural regulation of the airway smooth muscle (ASM). The exposure to polluted air may deteriorate these properties with harmful consequences to individual health. Formaldehyde (FA) is an important indoor pollutant found among volatile organic compounds. This pollutant permeates through the smooth muscle tissue forming covalent bonds between proteins in the extracellular matrix and intracellular protein structure changing mechanical properties of ASM and inducing asthma symptoms, such as airway hyperresponsiveness, even at low concentrations. In the experimental scenario, the mechanical effect of FA is the stiffening of the tissue, but the mechanism behind this effect is not fully w1derstood. Thus, the aim of this study is to reproduce the mechanical behavior of the ASM, such as contraction and stretching, under FA action or not. For this, it was created a two-dimensional viscoelastic network model based on Voronoi tessellation solved using Runge-Kutta method of fourth order. The equilibrium configuration was reached when the forces in different parts of the network were equal. This model simulates the mechanical behavior of ASM through of a network of dashpots and springs. This dashpot-spring mechanical coupling mimics the composition of the actomyosin machinery of ASM through the contraction of springs to a minimum length. We hypothesized that formation of covalent bonds, due to the FA action, can be represented in the model by a simple change in the elastic constant of the springs, while the action of methacholinc (MCh) reduce the equilibrium length of the spring. A sigmoid curve of tension as a function of MCh doses was obtained, showing increased tension when the muscle strip was exposed to FA. Our simulations suggest that FA, at a concentration of 0.1 ppm, can affect the elastic properties of the smooth muscle fibers by a factor of 120%. We also analyze the dynamic mechanical properties, observing the viscous and elastic behavior of the network. Finally, the proposed model, although simple, ir1corporates the phenomenology of both MCh and FA and reproduces experirnental results observed with ir1 vitro exposure of smooth muscle to .FA. Thus, this new mechanical approach incorporates several well know features of the contractile system of the cells ir1 a tissue level model. The model can also be used in different biological scales.

Isolation of Sporothrix schenckii from the claws of domestic cats (indoor and outdoor) and in captivity in São Paulo (Brazil)

Sporotrichosis is a subcutaneous mycosis and is also a zoonosis (sapro- and anthropozoonosis). The objective of the present study was to determine the occurrence of sporotrichosis in domestic cats and in wild or exotic felines in captivity through the isolation of Sporothrix spp. from claw impressions in a culture medium. The samples included 132 felines, of which 120 (91.0 %) were domestic cats, 11 (8.3 %) were wild felines, and one (0.7 %) was an exotic felid. Twenty-one (17.5 %) were outdoor cats. Of the total, 89 (67.4 %) had contact with other animals of the same species. It was possible to isolate Sporothrix schenckii from the claws of one (0.7 %) of the felids probed; this animal exhibited generalised sporotrichosis and had infected a female veterinarian. The potential pathogenic agents Microsporum canis and Malassezia pachydermatis were isolated in 12.1 and 5.3 % of the animals, respectively. The following anemophilous fungi, which were considered to be contaminants, were also isolated: Penicillium sp. (28 or 21.2 %), Aspergillus sp. (13 or 9.8 %), Rhodotorula sp. (5 or 3.8 %), Candida sp. (5 or 3.8 %), Trichoderma sp. (1 or 0.7 %), and Acremonium sp. (1 or 0.7 %). Due to the low magnitude of occurrence (0.7 %) of Sporothrix in feline claws, the potential of the cats evaluated in this study to be sources of infection in the city of São Paulo is considerably low.