Schackcarney5986

It is well established that testosterone administration induces muscle fiber hypertrophy and myonuclear addition in men, however, it remains to be determined whether similar morphological adaptations can be achieved in women. The aim of the present study was therefore to investigate whether exogenously administered testosterone alters muscle fiber morphology in skeletal muscle of young healthy, physically active women. Thirty-five young (20-35 years), recreationally trained women were randomly assigned to either 10-week testosterone administration (10 mg daily) or placebo. Before and after the intervention, hormone concentrations and body composition were assessed, and muscle biopsies were obtained from the vastus lateralis. Fiber type composition, fiber size, satellite cell- and myonuclei content, as well as muscle capillarization were assessed in a fiber type-specific manner using immunohistochemistry. Following the intervention, testosterone administration elevated serum testosterone concentration (5.1-fold increase, P=0.001), and induced significant accretion of total lean mass (+1.9%, P=0.002) and leg lean mass (+2.4%, P=0.001). On the muscle fiber level, testosterone increased mixed fiber cross-sectional area (+8.2%, P=0.001), an effect primarily driven by increases in type II fiber size (9.2%, P=0.006). Whereas myonuclei content remained unchanged, a numerical increase (+30.8%) was found for satellite cells associated with type II fibers in the Testosterone group. In parallel with fiber hypertrophy, testosterone significantly increased capillary contacts (+7.5%, P=0.015) and capillary-to-fiber ratio (+9.2%, P=0.001) in type II muscle fibers. The current study provides novel insight into fiber type-specific adaptations present already after 10 weeks of only moderately elevated testosterone levels in women.During chewing, movements and deformations of the tongue are coordinated with jaw movements to manage and manipulate the bolus and avoid injury. Individuals with injuries to the lingual nerve report both tongue injuries due to biting and difficulties in chewing, primarily because of impaired bolus management, suggesting that jaw-tongue coordination relies on intact lingual afferents. Here, we investigate how unilateral lingual nerve (LN) transection affects jaw-tongue coordination in an animal model (pig, Sus scrofa). Temporal coordination between jaw pitch (opening-closing) and 1) anteroposterior tongue position (i.e., protraction-retraction), 2) anteroposterior tongue length, and 3) mediolateral tongue width was compared between pre- and post-LN transection using cross correlation analyses. Overall, following LN transection, the lag between jaw pitch and the majority of tongue kinematics decreased significantly, demonstrating that sensory loss from the tongue alters jaw-tongue coordination. In addition, decrease in jaw-tongue lag suggests that, following LN transection, tongue movements and deformations occur earlier in the gape cycle than when the lingual sensory afferents are intact. If the velocity of tongue movements and deformations remains constant, earlier occurrence can reflect less pronounced movements, possibly to avoid injuries. The results of this study demonstrate that lingual afferents participate in chewing by assisting with coordinating the timing of jaw and tongue movements. The observed changes may affect bolus management performance and/or may represent protective strategies due to altered somatosensory awareness of the tongue.The second gas effect occurs when high inspired concentrations of a first gas, usually nitrous oxide, enhance the uptake of other gases administered simultaneously. The second gas effect is greater in blood than in the gas phase; persists well into the period of nitrous oxide maintenance anesthesia; increases as the degree of ventilation-perfusion mismatch increases; and is most pronounced with the low soluble agents in current use. Yet, how low gas solubility and increased ventilation-perfusion mismatch can combine to improve gas transfer remains unclear, which is the focus of the present study. Specifically, we have used a two-step model of steady-state gas exchange to separate the effect of gas volume contraction, which accompanies the first gas uptake, from other factors. Step 1 involves the uptake of the second gas at constant volume. Contraction of gas volume takes place in step 2 and is most effective in transferring further amounts of gas to blood if the volume of second gas exposed to the contraction is maximized, i.e. if the loss of second gas in step 1 is minimized. Minimization depends on having a gas with a low solubility in blood and increases as the degree of ventilation-perfusion mismatch increases. The effectiveness of the contraction also requires a favorable alignment with the retained second gas. Alignment depends on the solubility of both gases and the degree of ventilation-perfusion mismatch. The model is fully consistent with the classical concepts of gas exchange.Massage is commonly used as a complementary therapy for many different conditions. Demonstration of its physiological impact and understanding of its therapeutic mechanisms is still insufficient and often inconclusive. This study aims to characterize the physiological effects of effleurage, one of the most popular techniques, on human in vivo microcirculation and its impact to cardiovascular function. Two differently oriented variations of the technique, referred to influence physiological outcomes, were applied to 32 young (mean 19.8 ± 1.6 years old) healthy volunteers of both genders in a single randomly chosen limb after informed written consent. Each protocol included a 10-minute baseline (Phase I), a 5-minute massage (Phase II), and a 10-minute recovery (Phase III) register. A 30-minute washout period separated both protocols. Perfusion was assessed by Laser Doppler flowmetry (LDF) and reflection photoplethysmography (PPG), with their sensors applied distally in both feet. Blood pressure and pulse were also obtained. LDF signals were further analyzed in their components by the (Morlet) Wavelet Transform to probe the mechanisms involved. TAK-779 in vitro Results showed that effleurage consistently evoked a significant (p less then 0.001) perfusion increase in the massaged limb, also visible in the contralateral limb (ns) independently from the orientation (variant) used. No matter the perfusion differences known between sexes, the adaptive response was equivalent in both sexes. The component analysis of the LDF curves also suggests that these procedures, although brief and superficial, do modify multiple components of cardiovascular integration, with cardiac, respiratory, and myogenic components appearing to play a major role in re-establishing distal microcirculatory homeostasis.