Insulin maintains glucose homeostasis through its binding of the insulin receptor and activation of the insulin signalling cascade in insulin sensitive tissues. Skeletal muscle is a major endocrine organ, and is responsible for the majority of post-prandial glucose disposal. The maintenance of glucose homeostasis is a delicate balance and impairments in glucose disposal can have significant physiological effects, resulting in the onset of metabolic diseases such as diabetes mellitus. Insulin stimulated glucose uptake involves a number of signalling proteins to enable uptake to occur. In order to understand the complexities associated with the insulin signalling cascade, cell culture models have provided a controlled and easily manipulated environment in which to investigate insulin stimulated glucose uptake in skeletal muscle. While the majority of these experiments have been conducted in conventional monolayer cultures, the growing field of three-dimensional tissue engineering provides an alternative environment in which skeletal muscle cells can be grown to investigate their physiological function. The purpose of this thesis was to investigate the use of different cell culture models for investigating the effects of acute and chronic insulin exposure on skeletal muscle. Initial investigations aimed to establish glucose uptake in tissue engineering skeletal muscle constructs using tritium labelled (H3) 2-deoxy-d-glucose. Monolayer cultures were used to developed base line conditions. In these cultures, concentrations greater than 0.5 μCi for 15 minutes of insulin stimulation suggested an initial assay window for investigating insulin stimulated glucose uptake. However, the duration of insulin stimulation was not effective in measuring uptake in tissue engineered skeletal muscle constructs based upon western blot experiments of Akt phosphorylation, therefore insulin stimulation in skeletal muscle tissue engineered constructs was increased to 30 minutes. Glucose uptake is mediated via specific glucose transporter protein, GLUT1 and GLUT4. Therefore, the transcriptional profile of these transporters was elucidated in monolayer culture and tissue engineered skeletal muscle constructs. Time course experiments showed an increase in GLUT4 transcription in tissue engineered and monolayer culture systems which is associated with an increase in the transcription of skeletal muscle development and myogenic genes. In two dimensional culture, skeletal muscle cells were exposed to insulin during differentiation and in post-mitotic skeletal muscle myotubes to investigating the potential effects upon metabolic genes and proteins involved in insulin signalling. Chronic exposure to insulin during skeletal muscle differentiation reduced insulin signalling and resulted in an increase in basal glucose uptake and ablated insulin stimulated glucose uptake. In contrast, post-mitotic skeletal muscle myotubes did not shown similar changes and were not as responsive to acute insulin exposure. Therefore future experiments exposed skeletal muscle to insulin during differentiation. Using the previous findings as a basis for experimentation, the effects of chronic and acute insulin exposure upon three dimensional skeletal muscle constructs were investigated. Fibrin and collagen constructs were grown for a total period of 14 days. Constructs were exposed to insulin during differentiation and acutely stimulated for 30 minutes at day 14. Although there was a mean increase in Akt protein phosphorylation in both types of tissue-engineered constructs, these changes were not significant following acute insulin stimulation. In addition, glucose uptake in fibrin skeletal muscle constructs increased as a result of acute insulin stimulation however was not significantly difference to unstimulated constructs. The work presented in this thesis provides initial experimental data of the use of different skeletal muscle cell culture models for investigating insulin signalling and glucose uptake. Further research should further characterise these in vitro models for investigating skeletal muscle metabolism.

Title: Efficacy of post - isometric relaxation technique on muscle tissue and its viscoelastic properties after physical activity. Objective: This study is a pilot analytical and comparative study. The first aim of this thesis was evaluation of the effect of post-isometric relaxation technique on properties of muscle tissue after physical activity. The second aim of this thesis is to present a literature review regarding this topic using literature available. Methods: This study took place in the laboratory of kinesiology at UK FTVS. Six participants were measured prior to Wingate test, after Wingate test and after post- isometric relaxation or rest. Experimental lower extremity was applied post-isometric relaxation technique and the control lower extremity was not. Muscle tonus of the soleus muscle was measured with myotonometric device developed by Šifta. The final data were processed in the special software in Matlab and the obtained hysteresis curves were used for results analysis. Results: This study had three hypotheses and none of them was confirmed during the measuremets. The first hypothesis pressumed that muscle tonus will increase after the Wingate test, but it was not confirmed and thus further measurements were strongly influenced in the sense that post-isometric relaxation was not...

Diss. (sammanfattning) Linköping : Linköpings universitet, 2009.

The purpose of this study was to compare the exercise and recovery muscle oxygenation response of Women and Girls during two 30s Wingate anaerobic tests separated by two minutes of active cycling recovery (resistance ≈ 2.5% body weight, 60-80rpm). Oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), total hemoglobin (tHb), and tissue saturation index (TSI) were monitored at the right vastus lateralis muscle using near infrared spectroscopy (NIRS) throughout exercise, recovery, and a post-exercise femoral artery occlusion to TSI plateau. Pressure was preset at 250mmHg for Women and 210mmHg for Girls, achieved by rapid inflation in 0.3 seconds, and maintained until a 2 minute TSI plateau occurred or 10 minutes had passed. Twenty Women (23.8[2.12] years) and 13 Girls (9[1] years, combined Tanner stage <4) completed all tasks excepting 1 girl who did not complete occlusion. Significant group, time, and group by time interaction effects were observed for peak and mean power (Watts.kgFFM-1). Women had significantly greater power output compared to Girls for both Wingates. While both groups had reduced power output in Wingate 2, the reduction was significantly greater in Women compared to Girls. No significant group differences were found for resting TSI, recovery TSI, minimum TSI during either Wingate test, or for minimum TSI during occlusion, however a time main effect for Women was observed with minimum TSI being significantly lower in Wingate 1 compared to Wingate 2. Girls had similar minimum TSI for both Wingate tests. Women also demonstrated a significantly greater difference between Wingate minimum TSI and occlusion minimum TSI in Wingate 2 compared to Wingate 1. During Wingate 1, HHb increase was greater in Girls compared to Women and remained elevated during recovery compared to women. Changes in HbO2, HHb, and tHb were reduced in Wingate 2 for both groups, more so in Women for tHb and in Girls for HHb. Recovery was not different between groups with the exception of a faster TSI time constant of recovery in Women (τ =20.25 [13.01]s) compared to Girls (τ =36.77 [13.38]s) which is attributed to a faster HHb time constant in Women (τ =13.6 [0.44]s) compared to Girls (τ =30.77[19.47]s). Both groups demonstrated similar power output results and TSI response across the two Wingate tests but Girls were better able to repeat the anaerobic performance with a consistent TSI minimum between the two tests despite a faster recovery of HHb and TSI in women. These findings, in the context of observed Hb variable differences between groups, provide evidence of greater oxidative metabolism in Girls during a high intensity exercise. / Graduate / December 18, 2016

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第22671号 / 人博第957号 / 新制||人||227(附属図書館) / 2020||人博||957(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 川本 卓男, 教授 宮下 英明, 教授 高田 穣 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

No description available.

Background: Hospital malnutrition is a prevalent issue with critically ill pediatric patients being at increased risk for nutritional loss. Nutritional risk screening has been associated with increased documentation of nutrition diagnosis and positive clinical outcomes, however, is not mandatory in developing countries. A nutrition screening tool that uses subjective examination of loss of subcutaneous fat and muscle tissue may be an efficient way to identify nutritional risk in hospitalized critical care pediatric patients. Objective: To determine whether loss of subcutaneous fat and muscle tissue in specific body locations was associated with moderate or severe malnutrition determined by SGA in pediatric critical care hospital units, and if loss of subcutaneous fat and muscle tissue differs by gender, age, or disease. Methods: Pediatric in-patients (n = 203), aged 1 month to 18 years old, in tuberculosis, burn, oncology, high dependency (HDU) and intensive care units (ICU) in two tertiary hospitals in Malawi were assessed for nutritional status using Subjective Global Assessment (SGA), Mid-upper arm circumference (MUAC), and weight for age Z-score (WAZ). The SGA form included four questions on weight, appetite, tolerance to food and fluids, and dietary intake, as well as a nutrition-focused physical exam. The nutrition-focused physical exam consisted of assessments of subcutaneous fat loss in two locations (below the eye, triceps/biceps) and eight locations for muscle tissue loss (temple, clavicle, shoulder, scapula, interosseous, knee, quadriceps, and calf). The analysis was focused on the assessment of loss of subcutaneous fat and muscle tissue in relation to malnutrition score determined by SGA. Results: The mean age and standard deviation of the study population was 5.32 years ± 4.80, with just over 55% of participants being male. Determined by SGA, moderate malnutrition prevalence was 70.9% and severe malnutrition prevalence was 13.8%. SGA alone identified more malnutrition (84.7%) than MUAC (20.5%) and WAZ (43%). Patients with cancer (100%) and organ-related disease (93.76%) had the highest rates of moderate and severe malnutrition. Loss of subcutaneous fat and muscle tissue in all body locations assessed were associated with moderate and severe malnutrition (p-value Conclusions: A nutritional screening tool that is efficient, valid, and allows for the screening of a large patient population in a short amount of time, is needed in Malawi. Although loss of subcutaneous fat and muscle tissue were significantly associated with moderate and severe malnutrition, moderate loss of muscle tissue in the quadriceps and calf had the highest odds of malnutrition. These results indicate that pediatric patients with moderate loss of muscle tissue in their quadriceps and calf should be treated with a high index of suspicion for malnutrition. While loss of subcutaneous fat and muscle were not significantly worse by gender, age, or disease, particular attention should be paid in patients of the male sex, aged 6 to 10 years old, and with cancer. These findings support increasing dietetic services to prevent and treat hospital malnutrition using simple screening tools, such as the one used in this sub-analysis.

No description available.

Mechanical properties of muscle tissue are linked to its function. Magnetic Resonance Elastography (MRE) has the capability toquantitively measure these mechanical properties of soft tissue in-vivo. However, most MRE methods assume tissue isotropy during MRE reconstruction which is not an appropriate assumption for muscle tissue. To obtain tissue mechanical properties with higher accuracy, muscle anisotropy must be considered during MRE reconstruction. Therefore, the aim of this thesis was to implement an anisotropic MRE reconstruction. The anisotropic MRE reconstruction used solves three independent viscoelastic parameters (G||, G⊥, E||), that is based on a transverse isotropic (TI) inversion. The reconstruction was validated in a phantom study by comparison with an isotropic reconstruction, and in-vivo on gastrocnemius (ankle plantar flexor) and tibialis anterior (ankledorsi flexor) of one human subject. Also, a TI phantom was created to be included in the phantom study along with a commercial isotropic phantom. However, due to poor image quality, the TI phantom was excluded from further validation. Results from the isotropic phantom did not agree with the assumption of equal shear modulus in different planes of the isotropic medium. In-vivo study showed that the anisotropic reconstruction yielded mean moduli values in the range of what the literature suggests. The unequal shear modulus and young's modulus G||≠G⊥≠E|| of anisotropy in TI material was observed, indicating that the reconstruction method was able to identify the anisotropy ofmuscle tissue. However, further analysis including more human subjects are needed to conclude the reliability of the reconstruction method. / Muskelvävnadens mekaniska egenskaper är kopplade till dess funktion. Magnetresonans-Elastografi (MRE) har förmågan att kvantitativt mätadessa mekaniska egenskaper i mjukvävnad in-vivo. De flesta MRE metoder antar dock att vävnaden är isotropisk under MRE rekonstruktionen, vilket inte är ett lämpligt antagande för muskelvävnad. För att med högre noggrannhet estimera mekaniska egenskaper i vävnad måste muskel anisotropi tas i hänsyn under MRE rekonstruktionen. Därav var syftet i denna uppsats att implementera en anisotropisk MRE rekonstruktion. Den implementerade anisotropa MRE rekonstruktionenlöser tre oberoende viskoelastiska parametrar (G||, G⊥, E||), som ärbaserad på en transversell isotropisk (TI) inversion. Rekonstruktionen validerades i en fantomstudie genom jämförelse med en isotropisk rekonstruktion samt in-vivo på gastrocnemius (ankel plantarflexion) och tibialis anterior (ankel dorsalflexion) hos en människa. Dessutom skapades en TI-fantom för att inkluderas i fantomstudien tillsammansmed en kommersiell isotropisk fantom. På grund av dålig bildkvalitet uteslöts TI-fantomen från ytterligare validering. Resultat från den isotropa fantomen överensstämde inte med antagandet om lika skjuvmodul i olika plan av det isotropa mediet. In vivo-studien visade att den anisotropa rekonstruktionen gav medelvärden för modulerna inom intervallet av vad litteraturen antyder. Olikheten av skjuvmodulen och elasticitetsmodulen för anisotropi i TI-material G||≠G⊥≠E|| observerades vilket är en indikation att rekonstruktionsmetoden kunde identifiera muskelvävnadens anisotropi. Det krävs dock ytterligare analys inklusive fler mänskliga försökspersoner för att dra slutsatsen ifall rekonstruktionsmetoden är tillförlitlig

Investigamos o efeito do exercício físico no metabolismo do tecido adiposo e muscular de ratos pinealectomizados tratados ou não com melatonina. Foram retiradas amostras de sangue, tecido adiposo peri epididimal e músculo sóleo para testes biológicos. O treinamento físico mostrou-se eficiente através do aumento da velocidade máxima, atingida no final do treinamento, e da atividade da citrato sintase no músculo. A pinealectomia alterou o padrão de mobilização e utilização dos substratos pelos adipócitos e células musculares tornando menor a adaptação dos animais ao treinamento, causando um desajuste metabólico em vários parâmetros. Quando tratados com melatonina a adaptação funcional recuperou-se plenamente, tanto no tecido adiposo como muscular. Demonstrando que a glândula pineal tem um papel na regulação do metabolismo de lipídeos e carboidratos em resposta ao treinamento físico, a remoção da glândula causa alterações na resposta adaptativa do tecido adiposo e muscular e o tratamento com melatonina reverte o desajuste metabólico instaurado pela pinealectomia. / The current study investigated the effect of exercise on muscle and adipose tissue metabolism melatonin treated or non treated pinealectomized rats. Blood samples, peri-epididymal adipose tissue and soleus muscle were collected for biological tests. The physical training was efficient in increasing the maximum speed reached at the end of training, and the activity of citrate synthase in muscle. Pinealectomy changed the pattern of mobilization and utilization of substrates adipocytes and muscle cells decreasing the adjustment to the training in these animals, causing a mismatch in several metabolic parameters. When treated with melatonin, the functional adaptation is fully recovered both in adipose tissue and muscle. Demonstrating that the pineal gland has a role in regulating the metabolism of lipids and carbohydrates in response to physical training, the removal of the gland caused changes in the adaptive response of adipose tissue and muscle and the treatment with melatonin reversed the metabolic mismatch introduced by pinealectomy.