The control of skeletal muscle relies on a complex integration between descending central input and information that originates from receptors that lie within peripheral tissue. The following investigations were performed to contribute to our understanding of this control. Study 1 ( Chapter 2 ) was designed to determine ( using the H - reflex ) if muscle spindle feedback is similar in the gastrocnemius and soleus. The strength of the H - reflex at rest and during contraction was compared between muscles. The results showed that the maximal H - reflex obtained at any level of contraction is larger in the soleus than in the gastrocnemius. We argue that along with the muscles having different structures and functions, the recruitment capabilities of their motoneurons are quite different. We also found that the maximal M - wave, which has for years been thought to be a consistent measure of maximal muscle activity, was quite variable within subjects during different conditions. Review of the maximal M - wave literature showed evidence that variability in this response did exist between conditions, but that the variability was rarely seen in pooled data, and was therefore not often reported. Study 2 ( Chapter 3 ) was developed to determine if experimental recording techniques, or analysis methods, could affect the magnitude of the maximal M - wave within subjects. The first finding of this study showed that the two most commonly used analysis methods ( peak - to - peak amplitude and area ) provided comparable results, and could not account for the differences seen in the maximal M - wave magnitude. The study did however suggest that the orientation of surface recording electrodes can significantly alter the recorded signal. We argue that although bipolar surface recording is considered superior to monopolar recording in its ability to record a clean signal, it has a large limiting factor, which we call " signal cancellation ". The third study ( Chapter 4 ) focused on the variability in M - wave strength in the gastrocnemius and soleus during a variety of ankle orientations and voluntary contraction levels. This study supported our previous work, and showed that when monopolar recording is used, consistent and significant differences exist in the strength on the M - wave obtained during different conditions that were not seen in bipolar recordings. It was concluded that the difference in maximal M - wave strength obtained during different muscle conditions may be related to a change in the recording electrode to muscle bulk relationship. This finding is important as M - wave strength is consistently used as a normalisation factor in reflex studies, and therefore variability in this measure may seriously affect the results obtained during muscle reflex investigations. The final study ( chapter 5 ) considered the size of the H - reflex, the level of background muscle activity, and the subjects ' weight distribution, during painful and non - painful conditions. We determined that these factors were not modified by pain induced in either agonist or antagonist muscles. The final chapter outlines the major findings from this work, highlights limitations to the research conducted using the H - reflex, and makes suggestions for future research in this area. / Thesis (Ph.D.)--School of Molecular and Biomedical Science, 2006.

Abstract Introduction: The prevalence of anterior cruciate ligament tear is around 7000 every year within the swedish population and 95% of reconstructive surgery was with a hamstring tendon graft. Six months post surgery a 13% decrease in knee flexion strength compared to non injured side. The need for a study that determine the role of gastrocnemius and foot position in knee flexion is lacking in the litterature and could benefit Physiotheraphy ACL rehabilitation. Purpose: of his study was to investigate M gastrocnemius medialis (MGM) activation in the ipsilateral knee after removal of hamstring tendon for ACLR, and se if ankle position alter knee flexion outcomes. Method: 3 women, mean age 24 years who underwent ACL reconstruction with hamstring graft on one leg was tested. The time since injury was 3, 6 and 7 years respectively with an mean ,5 years wait until surgery. Isokinetic knee flexion and extension testing was done in the Biodex system 3 pro. EMG electrodes measured medial gastrocnemius activation with and without ankle in dorsiflexion. Results: Knee flexion peak strength was higher by a mean of 3 Nm (3,5%) with dorsiflexed foot. Mean (MGM) activation remained the same with or without dorsiflexion. Overall knee flexion strength was higher by a mean of 5 Nm compared to the injured side. Conclusion: Knee flexion in the biodex with foot in dorsiflexion could allow for isometric plantarflexion and increas power output. Certain changes in inclusion criteria and methodology as well more studies is needed to come to a given conclusion. / nej

Made available in DSpace on 2014-06-11T19:22:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-05Bitstream added on 2014-06-13T20:28:20Z : No. of bitstreams: 1 novellifilho_jlvb_me_botfm.pdf: 1212917 bytes, checksum: 117622a272f4c3d2881aed9520f95df9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A lesão do tendão do calcâneo é comum em humanos. Entretanto, existem muitas opiniões sobre o melhor tratamento para esta lesão quando diagnosticada tardiamente, e apesar do grande número de estudos, o melhor procedimento cirúrgico para o reparo ainda não foi identificado. No presente trabalho um modelo experimental foi desenvolvido em coelhos, para o reparo do tendão do calcâneo, com retalho único da fáscia miotendinosa do M. gastrocnêmio. Foram utilizados vinte e quatro coelhos machos adultos, de peso médio 3382g, divididos em três grupos de oito animais, submetidos à reconstrução cirúrgica do tendão do calcâneo, realizada no membro caudal direito, com o grupo controle no membro caudal esquerdo, não operado. O estudo foi realizado com três tempos de evolução pós-operatória: grupo (T0) amostras coletadas logo após a cirurgia; grupo (T1) amostras coletadas quatro semanas após a cirurgia; grupo (T2) amostras coletadas dezoito semanas após a cirurgia. Os animais apresentaram elevação significativa do peso corporal após 18 semanas da cirurgia. Houve redução na carga máxima, tensão, módulo de elasticidade, energia/área e energia na carga máxima imediatamente após a cirurgia. Após 4 semanas, a carga máxima, tensão, módulo de elasticidade, energia/área e energia na carga máxima mostraramse reduzidas em comparação ao controle. Após dezoito semanas os parâmetros mecânicos deformação, tensão, energia na carga máxima e energia/área foram restabelecidos. Concluiu-se no presente estudo, que a reconstrução do tendão do calcâneo com retalho único da fascia miotendinosa do M. gastrocnêmio, não se igualou ao controle em todos os parâmetros mecânicos após dezoito semanas, e que o modelo experimental foi adequado para a reprodução desta técnica cirúrgica em coelhos. / Calcaneus tendon injuries are commom in humans. However, there are many opinions about the best treatment for this lesion when too late diagnosed, and despite the large amount of studies, the best surgical procedure for repair wasn´t identified yet. In this study a experimental model in rabbits was developed for calcaneus tendon repair, with one single morsel from M. Gastrocnemius fascia. Twenty four male adult rabbits were employed, with medium weight 3382g, divided in three groups with eight animals each, submited to surgical procedure for repair of calcaneus tendon, accomplished on the rigth hind limb, with the control group on the left hind limb, not operated. The study was developed with 3 post-operation evolution times: group (T0) samples colected just after surgery; group (T1) samples colected four weeks after surgery; group (T2) samples colected eighteen weeks after surgery. The animals have had rising on weight bearing after eighteen weeks of surgery. There was reduction on maximum load, stress, elasticity modulus, energy/area and energy on maximum load just after surgery. After 4 weeks, the maximum load, stress, elasticity module, energy/area and energy on maximum load showed reduction in comparison with control. After eighteen weeks of surgery, the mechanical parameters deformation, tension, energy on maximum load and energy/area were restabilished. We concluded in this study, that the repair of the calcaneus tendon with one single morsel from M. gastrocnemius fascia, did not equalize with control group in all mechanical parameters after eighten weeks, and the experimental model, was suitable for the reproduction of this technic in rabbits.

The present study was undertaken to determine the relationship between perinatal complications and subsequent development of Attention Deficit Hyperactivity Disorder (ADHD) and other behavioral characteristics. The biological mothers of 74 children diagnosed with ADHD and 77 children displaying no characteristics of the disorder completed the Maternal Perinatal Scale (MPS), the Behavior Assessment System for Children-Parent Rating Scales (BASC-PRS), and a demographic survey. In addition, the biological mothers of 120 children with no characteristics of ADHD or any other behavior disorders completed only the MPS so that exploratory factor analysis of the MPS could be completed.Following factor analysis, stepwise discriminant analysis of the resulting five factors was utilized to explore the nature of the relationship between such perinatal factors and ADHD. Results of this analysis indicated that emotional factors, or the amount of stress encountered during pregnancy and the degree to Relationship Between Perinatal Complications 3 was planned, were the items that maximized the separation between the ADHD and Non-ADHD groups. Additional discrimination between the groups was attributed to the extent of insult or trauma to the developing fetus and the outcome of prior pregnancies. ADHD children were also found to have experienced twice as many behavioral, social, or medical problems, and were more likely to reach developmental milestones with delays.Stepwise discriminant analysis also revealed the Attention Problems and Hyperactivity scales of the BASC-PRS were most significant in differentiating between the ADHD and Non-ADHD subjects. Using the BASC-PRS resulted in approximately 90% of the total sample being correctly classified as ADHD or Non-ADHD. Canonical correlation analysis indicated that emotional factors and the general health of both the mother and the developing fetus were the best predictors of later behavioral patterns reported on the BASC-PRS. / Human Performance Laboratory

The ability of the heart and skeletal muscles to remodel to environmental demands, their plasticity, is of interest when studying animals’ adaptation to environment changes. Temperature variation due to seasonal change seems to lead to the development of a cold acclimated phenotype in small birds. To endure cold conditions a higher metabolism is required for shivering thermogenesis in aerobic skeletal muscles. This in turn leads to several physiological changes, including a heart and muscle hypertrophy as well as an increased oxygen carrying capacity of the blood. In this study were Red Junglefowls (Gallus gallus) bred indoors and outdoors and physiological aspects such as body size, growth rate, relative size of heart and skeletal muscles (pectoralis major and gastrocnemius maximus) as well as hematocrit and hemoglobin concentrations of the blood were compared between the groups. Observed significant differences included a slower growth rate in fowls bred outdoors, 2.5 (0.7) g/day than indoors, 3.8 (0.4) g/day, as well as a larger relative size of the heart and gastrocnemius muscle. The average relative size of the heart was more than twice as big in fowls bred outdoors, 0.97 (0.08) %, than indoors, 0.40-42 (0.05) %. The average relative size of the gastrocnemius muscle for the fowl bred outdoor was significantly larger than for fowl bred indoors (0.95 (0.11) %, vs. 0.58-0,63 (0.09) %). In addition, fowl bred outdoors showed an increased capacity for oxygen transportation, with blood hematocrit values of 43 (3) % higher than 35-37 (3) % for the indoor animals. Fowls bred outdoors also showed higher hemoglobin concentrations in the blood, 127 (7) g/l, than fowls bred indoors, 113 (7) g/l. Findings indicate a cold acclimated phenotype among the outdoor bred fowls.

Loss of muscle due to aging is often associated with significant detrimental effects. Therefore, it is crucial to understand signaling molecules that may trigger the muscle loss or prevent the process. The transcription factor, Nuclear Factor Kappa-B (NF-κB), is associated with both catabolic and anabolic pathways of muscle metabolism and may be involved in age-related muscle loss. Leucine is an essential amino acid that is required for both protein synthesis and intracellular signaling pathways that regulate protein synthesis and degradation. The current study examined muscle NF-kB levels in male Sprague-Dawley rats, aged 6 (adult) and 21 months (old) fed a diet containing suboptimal leucine levels for 10-17 days. We found that old rats consumed less grams of food per body weight (BW) each day than adult rats (1.45% g diet/g BW vs. 2.4% g diet/g BW). Weight loss during the study was not significantly different between age groups. However the average mass of gastrocnemius and soleus muscles (g muscle/g BW) was significantly lower in old rats. Reduction in gastrocnemius (g muscle/g BW*10²) was associated with 1.8 fold higher muscle cell NF-κB in old vs. adult rats (p = 0.0443). There was also a higher level of ubiquitinated proteins in old gastrocnemius muscle cells relative to the adult gastrocnemius, however differences did not reach statistical significance. For tibialis anterior muscle, the average mass (g muscle/g BW*10²), NF-κB levels and ubiquitinated proteins were not significantly different between adult and old rats. Our findings suggest that aging affects muscle loss and NF-kB in a tissue-specific manner in rats fed a diet with suboptimal leucine levels.

No description available.

Avaliamos a influência da imobilização, remobilização livre, remobilização com alongamento passivo manual, remobilização com estimulação elétrica neuromuscular (EENM) e remobilização com estimulação elétrica e alongamento passivo associados sobre algumas propriedades mecânicas do músculo gastrocnêmio de ratas. Foram utilizadas 60 ratas albinas da variedade Wistar e divididas em 6 grupos experimentais. Um grupo foi utilizado como controle. Cinco grupos tiveram o membro posterior direito imobilizado por 14 dias consecutivos. Destes 5 grupos um foi submetido à morte logo após o período de imobilização, um foi liberado da imobilização permanecendo em gaiolas plásticas por 10 dias, outro foi submetido a técnica de alongamento passivo manual por 10 dias consecutivos, outro foi submetido a EENM por 10 dias consecutivos e o último foi submetido a EENM somado ao alongamento passivo manual por 10 dias consecutivos. Após os períodos de intervenção os animais foram mortos e em seguida realizados os ensaios mecânicos de tração longitudinal dos músculos. As propriedades mecânicas avaliadas foram a carga e alongamento no limite de proporcionalidade e no limite máximo, a rigidez e a capacidade de absorver energia na fase elástica (resiliência) do músculo, obtidas a partir das curvas carga versus alongamento. Observamos que a imobilização provocou redução significativa nos valores das propriedades mecânicas avaliadas no músculo gastrocnêmio. A remobilização por alongamento passivo manual devolveu ao músculo as propriedades de alongamento no limite de proporcionalidade, rigidez e resiliência a padrões controle, entretanto não foi capaz de restabelecer as propriedades de carga no limite de proporcionalidade, carga e alongamento no limite máximo. A remobilização constituída por EENM restabeleceu todas as propriedades estudadas a padrões controle. A remobilização por estimulação elétrica somada ao alongamento passivo restabeleceu as propriedades mecânicas de alongamento no limite máximo e de proporcionalidade e rigidez, no entanto não foi capaz de devolver ao músculo suas propriedades carga no limite máximo, carga no limite de proporcionalidade e resiliência. A remobilização livre não foi capaz de restabelecer nenhuma das propriedades a padrões controle / We evaluated the influence of immobilization, free remobilization, remobilization with manual passive stretching, remobilization with neuromuscular electric stimulation (NMES) and remobilization with electric stimulation and passive stretching associated upon some mechanical properties of the gastrocnemius muscle of female rats. We used sixty female albinic rats of the variety Wistar and divided them in 6 experimental groups. One of these groups was used as control. The animals of the five other groups had their right hind immobilized for 14 consecutive days. From the five groups, one was submitted to death right after the immobilization period, a second was set free from the immobilization remaining in plastic cages for 10 days, a third was submitted to the manual passive stretching technique for 10 consecutive days, a fourth was submitted to NMES for 10 consecutive days and the last one was submitted to NMES and manual passive stretching for 10 consecutive days. After the intervention periods, the animals were submitted to death and afterwards the mechanical tests of longitudinal traction of the muscles were done. The mechanical properties evaluated were the load and the stretching in the limit of proportionality and in the maximum limit, the stiffness and the capacity to absorb energy in the elastic phase (resilience) of the muscle, obtained based on the curves load versus stretching. We observed that the immobilization has provoked significant reduction of the values of the mechanical properties evaluated in the gastrocnemius muscle. The remobilization by the manual passive stretching gave back to the muscle the mechanical properties of stretching in the limit of proportionality, stiffness and resilience like the standard ones of the control group, but it was not capable of reestablishing the properties of load in the limit of proportionality, load and stretching in the maximum limit. The remobilization done by the NMES reestablished all of the properties studied like ones of the control group. The remobilization by electric stimulation and passive stretching reestablished the mechanical properties in the maximum limit and in the proportionality and stiffness, although it was not capable of giving back to the muscle its properties of load in the maximum limit, load in the limit of proportionality and resilience. The free remobilization was not capable of reestablish any of the properties like the ones of the control group

Orientador: Julieta Rodini Engrácia de Moraes / Banca: Carlos Eduardo Ambrósio / Banca: Renée Laufer Amorim / Banca: Mirela Tinucci Costa / Banca: Maria de Jesus Veloso Soares / Resumo: A Distrofia Muscular no Golden Retriever (DMGR) é doença muscular degenerativa hereditária que representa excelente modelo para o estudo da Distrofia Muscular de Duchene de humanos. Esta pesquisa objetivou estudar as lesões do músculo gastrocnêmio (MG) e da junção músculo tendínea (JMT), na ausência de distrofina em cães afetados por distrofia muscular. Foram utilizados seis cães distróficos para distrofia muscular e três cães controle que vieram a óbito por causas variadas que não afetavam o sistema músculo esquelético. Após necrópsia completa, setenta e cinco fragmentos musculares do MG e da JMT foram colhidos em duplicata. Metade destes foi fixada em solução de formol e o restante foi congelado em nitrogênio líquido. Seguiram-se as técnicas usuais para inclusão em parafina e coloração pelo método Picrosirius, HE e TGM para análise histopatológica. Reações imuno-histoquímicas para MHCII e vimentina foram realizadas nos cortes em parafina. Os fragmentos congelados foram processados para colorações especiais para cálcio, alizarina Red S; reações enzimo-histoquímicas de fibras do tipo I (FTI) e II (FTII), mATPase (pH 9,4); e imuno-histoquímicas para CD4, CD8, MHCI e utrofina. Resultados da análise histopatológica mostraram que as lesões no MG de distróficos foram mais pronunciadas que na JMT. A análise histomorfométrica no MG de distróficos revelou maior porcentagem de FTII e menores valores de diâmetro mínimo e área para FTI e FTII. Para os parâmetros supracitados, as FTII na JMT mantiveram-se morfologicamente iguais ao controle. Não houve diferença quanto ao tipo de colágeno na JMT de distróficos e controle. Nas reações imuno-histoquímica para os anticorpos CD4, CD8, MHCI, MHCII, vimentina e utrofina, somente o antígeno MHCI apresentou diferença significativa (p< 0.07), quando comparado ao controle, sendo a imunoexpressão mais ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Muscular Dystrophy in Golden Retrievers (DMGR) is a hereditary degenerative muscle disease that represents an excellent model for the study of Duchenne Muscular Dystrophy. The aim of this study was to characterize the lesions in gastrocnemius muscle (GM) and myotendinous junction (MTJ) in absence of dystrophin in dogs affected by progressive muscular dystrophy. Six affected dogs and three control dogs, without musculoskeletal system diseases, were used. After necropsy, seventy-five myotendinous and muscle samples were cut and collected in duplicate. Half of them were fixed in formalin solution, and the other half were frozen in liquid nitrogen. After that, the samples were processed by usual techniques of paraffin embedding and stained by Picrosirius method, HE and TGM, for histopathological analysis. Immunohistochemical reactions for MHCII and vimentin were performed in paraffin samples. The frozen fragments were processed for special stains for calcium, Alizarin Red S, enzymohistochemical reactions of type I fibers (FTI) and II (FTII), mATPase (pH 9.4), and immunohistochemical for CD4, CD8, MHCI and utrophin. The results of histopathological analysis of the dystrophic dogs showed that the lesions in GM were more pronounced than MTJ. Histomorphometric analysis of the dystrophic GM showed the highest percentage of FTII, and lower values of minimum diameter and area for FTI and FTII. For the same parameters, the FTII in dystrophic MTJ remained morphologically similar to control. There was no difference in the type of collagen in MTJ of dystrophic and control. In immunohistochemical reactions to antibodies CD4, CD8, MHCI, MHCII, vimentin and utrophin, only the antigen MHCI showed a significant statistic difference (p <0.07) compared to control, being the most intense immunostaining in GM dystrophic. From these results we can conclude that the preservation of morphological MTJ can be ... (Complete abstract click electronic access below) / Doutor

As Stanniocalcinas (STC1 e STC2) são hormônios glicoproteicos originalmente encontrados em peixes teleósteos. Em mamíferos, esses hormônios são expressos em uma variedade de tecidos e estão envolvidos em processos como o transporte de cálcio e fosfato pelos rins e intestino, a carcinogênese, a reprodução e o crescimento. Recentemente, foram encontrados efeitos da STC1 e da STC2 no metabolismo intermediário. Sítios de ligação para a STC1 já foram identificados na membrana mitocondrial e resultados preliminares do nosso laboratório demonstraram que a STC1 possui um efeito inibitório sobre a gliconeogênese renal e tanto a STC1 quanto a STC2 diminuem a incorporação de 14C-glicose em 14CO2 no fígado e no músculo gastrocnêmio, respectivamente, de ratos. No entanto, o papel desses hormônios no metabolismo de aminoácidos permanece desconhecido. No presente trabalho, as ações da STC1 e da STC2 foram avaliadas no fígado e no músculo gastrocnêmio excisados de ratos machos (Rattus norvegicus, n=48 animais) de 300±50g, alimentados ad libitum. Os resultados obtidos mostram que a STC1, no fígado, diminuiu a captação do ácido 2-(metilamino)isobutírico, aumentou a atividade da bomba Na+/K+-ATPase, diminuiu a atividade da enzima malato desidrogenase mitocondrial e estimulou a síntese de glicogênio a partir da alanina. A STC2, no fígado, diminuiu a atividade da enzima malato desidrogenase mitocondrial, estimulou a síntese de proteínas a partir de leucina, e estimulou a síntese de glicogênio a partir de alanina. Já, no músculo, a STC2 estimulou a oxidação de leucina e a incorporação desse aminoácido em proteínas. Esses resultados confirmam a existência de ações das STC1 e STC2 no metabolismo de aminoácidos e sugerem, com exceção da ação da STC2 sobre a enzima malato desidrogenase, um papel anabólico para a STC2 em ambos os tecidos. A mesma afirmação não pode ser feita para a STC1, que apresentou efeitos antagônicos no tecido hepático. Por fim, o trabalho mostrou que as ações da STC1 e da STC2 sobre as vias metabólicas dos aminoácidos ocorrem com a utilização de doses muito baixas desses hormônios. / Stanniocalcins (STC) are glycoprotein hormones that were first discovered in teleostean fishes. In mammals, these hormones are expressed in a variety of tissues. Besides its role on the calcium and phosphate transport by the kidneys and intestine, they are involved in processes such as carcinogenesis, reproduction and growth. Recently it has been shown that STC1 and STC2 affect the control of intermediary metabolism. Binding sites for STC1 have been already identified in the mitochondrial membrane. Preliminary results of our laboratory showed that STC1 has an inhibitory effect on renal gluconeogenesis in rats and both STC1 and STC2 decrease the 14C-glicose incorporation into 14CO2 in the liver and the gastrocnemius muscle, respectively. Despite these evidences that STC1 and STC2 have a role in the control of glucose and lipids metabolism, the function of these hormones in amino acids metabolism remains unknown. In the present study, the STC1 and STC2 actions were evaluated in livers and gastrocnemius muscles excised from male rats (Rattus norvegicus, n=48 animals). The rats weighted 300±50g and were fed ad libitum. The results show that STC1 decreased 2-(metilamine)isobutyric acid uptake, increased Na+/K+-ATPase activity, decreased mitochondrial malate dehydrogenase activity and stimulated glycogen synthesis from alanine. All actions of STC1 were shown in the hepatic tissue and this hormone did not affect any parameter in muscular tissue. In the liver, STC2, decreased the mitochondrial malate dehydrogenase activity, stimulated protein synthesis from leucine and stimulated glycogen synthesis from alanine. In muscle, STC2 stimulated leucine incorporation into CO2 and proteins. These results confirm the regulatory role of STC1 and STC2 on amino acid metabolism in muscle and liver of rats. They suggest, with exception to the STC2 action into the hepatic malate dehydrogenase, an anabolic role for STC2 in both tissues. However this cannot be stated for STC1, which show antagonistic effects in the hepatic tissue. Lastly, another important finding of this study is that STC1 and STC2 actions on amino acid metabolism occur with low hormone concentrations.