High-tone extensor thrusts, or involuntary muscle contractions experienced by many children with cerebral palsy, can cause problems that are not addressed by current seating systems. This thesis is concerned with the development of a dynamic seating system to better accommodate individuals who exhibit high-tone extensor thrusts. The first part of the thesis is focused on obtaining a general understanding of extensor thrusts from a mechanical perspective. To achieve this goal, an analytical dynamic model of a human subject undergoing an extensor thrust on a rigid chair is created. This model is validated experimentally, and inferences about the nature of extensor thrusts are made from the simulation and experimental results. A Dynamic-Hingeback Seating System which allows the occupant to lean back during an uncontrolled extensor thrust is developed. This system is capable of maintaining seatback rigidity during an intentionally-induced episode, thereby enabling the occupant to communicate or interact with his/her environment. The design of this system is influenced by the results obtained from the rigid seat study, as well as by numerical simulation results gathered with a commercial dynamic simulation software package (Working Model 2D). The improved seatback performance is characterized through experimentation. Alternative dynamic seating systems are considered. The important features of each of these systems are identified, and the desired motion of the system occupant during an extensor thrust is verified through Working Model simulations.

Tyrimo objektas: rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčiai. Tyrimo problema: įvykus insultui, priklausomai nuo pažeidimo laipsnio, sutrinka ne tik dinaminės, bet ir kinematinės judesių savybės (pvz., tikslaus judesio trajektorija). Galvos smegenys reaguoja į pažeidimą kaip visuma, todėl sutrinka ne vienas, bet daugelis judesių (Skurvydas, 2008). Kadangi po insulto atsiranda apsitarnavimo problemos, ir yra ribojama kasdieninė veikla, norėjome ištirti ligonius, baigusius reabilitaciją, su nežymiais liekamaisiais reiškiniais bei nustatyti galūnių izometrinio susitraukimo variabilumo dydį, kuris atspindi atliekamo veiksmo stabilumą. Tyrimo tikslas: nustatyti rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčius po galvos smegenų insulto rezidualiniu periodu. Tyrimo uždaviniai: 1. Nustatyti ir palyginti tiriamosios bei kontrolinės grupės tiriamųjų dilbį lenkiančių ir blauzdą tiesiančių raumenų maksimalią valingą jėgą. 2. Nustatyti ir palyginti tiriamosios bei kontrolinės grupės tiriamųjų rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčius. 3. Nustatyti grįžtamojo ryšio įtaką izometrinio raumens susitraukimo variabilumui. Tyrimo hipotezė: galvos smegenų insultą patyrusių žmonių rezidualiniu periodu rankų ir kojų raumenų izometrinio susitraukimo variabilumas yra didesnis negu nepatyrusių galvos smegenų insulto. Tyrimo metodai ir organizavimas: tyrimas buvo atliktas LKKA Žmogaus motorikos laboratorijoje 2010 – 2011 metais... [toliau žr. visą tekstą] / Research object: changes of variability of the upper and lower extremities muscles isometric contraction. Research question: Subject to the degree of lesion, both dynamic and kinematic properties of motions (e.c., pathway of an accurate motion) can be disturbed after stroke. The cerebral brain reacts to lesion as whole, therefore disturbs not only one but many motinos (Skurvydas, 2008). Patient gets self-service problems after stroke and it limits daily activities, and it is the reason why we wanted to investigate patients who have inappreciable residual appearances after rehabilitation as well as we wanted to establish the value of variability of extremities isometric contraction, which reflects stability of movemt. Research purpose: to assess the changes of isometric contraction of upper and lower extremities muscles of residual post-stroke periode. Research goals: 1.To assess and compare the experimental and control group maximum voluntary strength of the forearm flexors and calf extensors; 2.To assess and compare the experimental and control group alterations of variability of the upper and lower extremities muscle isometric contraction; 3.To assess the influence of feedback on the muscle contraction variability. Research hypothesis: people at residual post-stroke periode have a higher variability of isometric contraction of the upper and lower extremities muscles than people people who did not undergo cerebral brain stroke. Research methods and organization: the... [to full text]

Šio eksperimentinio darbo tikslas buvo įvertinti 1,4-dihidropiridino ir benzimidazolo junginių poveikį jūros kiaulyčių širdies papiliarinių raumenų izometrinei funkcijai bei žmogaus kraujagyslių segmentų susitraukimui ir atsipalaidavimui. Buvo atlikti eksperimentiniai tyrimai su izoliuotais jūros kiaulyčių širdies papiliarinių raumenų preparatais ir izoliuotais žmogaus v.saphena magna ir a.thoracica interna kraujagyslių segmentais. Kraujagyslių preparatai gauti iš pacientų, kuriems buvo atliekamos širdies vainikinių arterijų jungčių suformavimo operacijos LSMU ligoninės Kauno klinikos Kardiochirurgijos klinikoje. Žmogaus izoliuotų kraujagyslių preparatų tyrimams išduotas Kauno regioninio bioetikos komiteto leidimas Nr. BE–2–64, data 2010–11–05. Buvo tiriamas 1,4-dihidropiridinų bei benzimidazolo junginių poveikis izometrinei jūros kiaulyčių širdies papiliarinių raumenų funkcijai, registruojant preparatų elektromechaninį susitraukimo jėgos ir transmembraninio veikimo potencialus. Eksperimentiniai tyrimai, atlikti in vitro sąlygomis, įvertinant 1,4-dihidropiridinų bei benzimidazolo junginių poveikį žmogaus izoliuotų kraujagyslių (v.saphena magna ir a.thoracica interna) segmentų susitraukimui ir atsipalaidavimui, skirtingų ekstraląstelinio Ca2+ koncentracijų įtaką tiriamųjų junginių poveikiui kraujagyslių segmentų susitraukimui ir atsipalaidavimui. Tiriamieji 1,4–dihidropiridinų junginiai sintezuoti Latvijos Organinės Sintezės institute. / This study aim was to evaluate the effects of 1,4-dihydropiridines and benzimidazole deriva¬tives on the isometric function of guinea pig papillary cardiac muscles and the contraction and relaxation of vascular segments in humans. The experiments were carried out on isolated samples of human great saphenous vein (v. saphena magna) and internal thoracic artery (a. tho¬racica interna). The vein and arteries samples were taken from patients who underwent coronary artery bypass. The study was approved by the Regional Ethics Committee of the Biomedical Research on 05/11/2010, license No. BE-2-64, Kaunas, Lithuania. The inotropic activity and transmembrane AP duration of the dihydropyridine derivatives were evaluated on the guinea-pig papillary muscles and aorta vascular samples. Synthesis of 1,4-dihydropyridine derivatives were performed in Latvian Organic Synthesis institute. During this study were performed the evaluation of 1,4-dihydropyridines and benzimidazole derivatives on contraction force and action potential in guinea pig papillary muscles. Effects of 1,4-dihydropyridines and benzimidazole derivatives on contraction and relaxation of the segments of the great sa¬phenous vein (v. saphena magna) and internal thoracic artery (a. tho¬racica interna) in humans, the extra-cellular concentration of Ca2+ and the effect of the studied compounds and were evaluated. Also assessment of preventive effect of the calcium channel blockers and benzimidazole derivative on contraction... [to full text]

Lic. (sammanfattning) Göteborg : Univ., 2004. / Härtill 2 uppsatser.

Thesis (Ph. D.)--University of Virginia, 2008. / Title from title page. Includes bibliographical references. Also available online through Digital Dissertations.

Thesis (M.S.)--University of Tennessee Health Science Center, 2006. / The electronic version of this thesis is available at http://etd.utmem.edu/WORLD-ACCESS/2006-002-yan.pdf Includes bibliographical references (leaves 128-136).

No description available.

La contraction des muscles striés est sous la dépendance du Complexe de Relâchement du Calcium (CRC). Ce complexe protéique est constitué principalement de deux canaux calciques, le récepteur des dihydropyridines, un canal sensible au voltage localisé dans la membrane des tubules-T et le récepteur de la ryanodine (RyR) situé dans la membrane du RS. Le CRC comprend également de nombreuses protéines régulatrices comme la triadine, la calséquestrine, la junctine et FKBP. Des mutations dans les gènes codant les protéines du CRC conduisent à des pathologies rares et souvent sévères. Cette thèse porte sur l'étude des mécanismes physiopathologiques induits par quelques unes de ces mutations pour décrypter les mécanismes pathologiques mis en œuvre mais également pour comprendre le fonctionnement global du CRC dans les muscles squelettique et cardiaque. La première partie de cette étude concerne RYR1, le gène codant l'isoforme squelettique du RyR qui est une cible importante de mutations chez des patients atteints de myopathies congénitales à cores. L'effet fonctionnel de ces mutations, réparties sur toute la séquence de RYR1, est peu connu. Ces mutations pourraient modifier la fonction canal de RyR1 mais également son adressage à la triade ou sa régulation par d'autres protéines du CRC. Parmi ces hypothèses, la modification de la localisation de RyR1 et sa régulation par une protéine régulatrice (la cavéoline-3) ont été révélées par l'étude de deux mutations de RyR1. La deuxième partie de cette étude concerne la tachycardie ventriculaire polymorphe catécholaminergique (TVPC), une pathologie liée à des défauts du CRC cardiaque, pour laquelle des recherches de mutations sont effectuées sur l'isoforme cardiaque du RyR, RYR2, puis dans les autres protéines du complexe. Nous avons identifié au laboratoire les premières mutations dans le gène de la triadine chez un de ces patients. L'impact d'une de ces mutations sur le fonctionnement du complexe a été étudié et nous avons pu caractériser le mécanisme physiopathologique mis en œuvre et conduisant à la TVPC chez ces patients. / The calcium release complex (CRC) plays a central role in both skeletal and cardiac muscle contraction. The composition of the complex is quite similar in both tissues, and differs only by tissue specific isoforms. The core of the complex is composed of the dihydropyridines receptor, a voltage sensor channel of the T-tubule and the ryanodine receptor, the sarcoplasmic reticulum calcium channel. A number of proteins are associated to this calcium channel like calsequestrin, triadin, junction and FKBP. Mutations in the skeletal CRC are responsible for rare and often severe diseases. This thesis work focuses on the study of physiopathological mechanisms induced by some of these mutations to decipher pathological mecanisms but also to understand the overall CRC functioning in skeletal and cardiac muscles. The first part of this study concerns RYR1, the skeletal RyR isoform coding gene. This gene is mostly the target of mutations resulting in core myopathies. The functional effect of these mutations spred on the entire RYR1 sequence is little known. These mutations could directly alter the calcium channel function but also its targeting to the triad or its regulation by other CRC proteins. Among these hypotheses, the modification of RyR1 localisation and regulation by a protein, Caveolin-3, have been highlighted with the study of two RyR1 mutations. The second part of this study concerns the catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare fatal arrhythmia caused in part by mutations in RYR2 and CASQ2, both belonging to the cardiac CRC,. Recently, we have identified the first mutations in the human triadin gene, TRDN, in a CPVT patient. The goal of this project was to study the molecular and physiological consequences of one of these TRDN mutations allowing the analysis of the pathological mechanisms of this disease, but also a better understanding of the normal function of the cardiac CRC.

A troponina (Tn) regula a contração do músculo estriado esquelético de vertebrados. Ela é composta de três subunidades: troponina I (TnI), troponina C (TnC) e troponina T (TnT). A TnI tem a função inibitória que é neutralizada pela ligação de Ca2+ nos sítios regulatórios do N-domínio da TnC, e a TnT posiciona o complexo no filamento fino. Para monitorar o sinal do Ca2+ sendo transmitido da TnC para a TnI as propriedades espectrais únicas do 5-hidroxitriptofano (5HW) foram utilizadas. O 5HW foi incorporado em mutantes pontuais de TnI com um único códon para triptofano. Foram identificadas duas sondas espectrais intrínsecas na TnI capazes de detectar a ligação de Ca2+ na Tn: as TnIs com 5HW nas posições 100 e 121. Complexos troponina reconstituídos com estes mutantes fluorescentes de TnI, Tn-TnIF100HW e Tn-TnIM121HW, apresentaram respectivamente 12 e 70 % de aumento na intensidade do espectro de emissão devido à ligação de Ca2+ na TnC. Nos complexos binários (TnC-TnI) as TnIs com 5HW nas posições 106 e 121 também captam a ligação do Ca2+ na TnC. A análise da fluorescência destas sondas demonstrou que: 1) as regiões da TnI que respondem ao N-domínio regulatório da TnC ocupado com Ca2+ são a região inibitória da TnI, resíduos 96 até 116, e a região vizinha que inclui a posição 121 da TnI; 2) mutações pontuais e a incorporação de 5HW na TnI podem afetar tanto a afinidade como a cooperatividade da ligação de Ca2+ na TnC, confirmando o papel da TnI em modular a afinidade da TnC por Ca2+; 3) as constantes de dissociação de Ca2+ surpreendentemente altas, Kd ~ 10-8 M, calculadas a partir dos sinais das sondas na região inibitória da TnI, sugerem a possibilidade de que os sítios do domínio N-terminal da TnC sejam os sítios de ligação de Ca2+ de maior afinidade no complexo troponina. / Vertebrate striated muscle contraction is regulated by troponin (Tn). Tn is composed of three subunits: troponin I (TnI), troponin C (TnC) and troponin T (TnT). TnI has an inhibitory role that is neutralized by calcium binding to the regulatory sites in the N-domain of TnC, and TnT positions the troponin complex on the thin filament. In order to follow the Ca2+ induced conformational change that is transmitted from TnC to TnI, the unique spectral properties of 5-hydroxytryptophan (5HW) incorporated as point-mutants of TnI were used. It was possible to identify two new TnI intrinsic spectral probes sensitive to Ca2+ binding to Tn: TnI with single 5HW at positions 100 and 121. Trimeric troponin complexes reconstituted with two fluorescent mutants of TnI, Tn-TnIF100HW and Tn-TnIM121HW, showed respectively 12 and 70 % increase in the emission spectra when Ca2+ bound to TnC. In the binary complexes (TnC-TnI) two TnIs with 5HW at positions 106 and 121 were also sensitive to Ca2+ binding to TnC. Fluorescence analysis of these probes showed: 1) the regions in TnI that respond to Ca2+ binding to the regulatory N-domain of TnC are the inhibitory region of TnI (residues 96 to 116), and a neighbor region that includes position 121; 2) point mutations and incorporation of 5HW in TnI can affect both the affinity and the cooperativity of Ca2+ binding to TnC, confirming the role of TnI as a modulator of the Ca2+ affinity of TnC; 3) the high dissociation constant for sites in the N-terminal domain of TnC (Kd ~ 10-8 M), derived from data using probes in the inhibitory region of TnI suggested the possibility that these sites are the high affinity Ca2+ binding sites in the troponin complex.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-30T12:20:50Z No. of bitstreams: 1 antoniopauloandredecastro.pdf: 1766727 bytes, checksum: 9e0fb7d47b81afb5f261067426a45e6c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T11:57:53Z (GMT) No. of bitstreams: 1 antoniopauloandredecastro.pdf: 1766727 bytes, checksum: 9e0fb7d47b81afb5f261067426a45e6c (MD5) / Made available in DSpace on 2016-07-02T11:57:53Z (GMT). No. of bitstreams: 1 antoniopauloandredecastro.pdf: 1766727 bytes, checksum: 9e0fb7d47b81afb5f261067426a45e6c (MD5) Previous issue date: 2012-03-29 / A investigação das propriedades eletrofisiológicas do sistema neuromuscular (SN) durante o processo de modulação da força muscular tem sido objeto de estudos em diversas áreas. Entre as técnicas empregadas com esta finalidade encontra-se a eletromiografia de superfície (sEMG). Em meio às condições patológicas potencialmente capazes de provocar alterações nas propriedades teciduais e fisiológicas do SN, e, consequentemente, nas propriedades eletrofisiológicas durante o processo de modulação da força, destaca-se o diabetes mellitus do tipo 2 (DM2). O objetivo do presente estudo foi investigar, através dos valores de frequência mediana (FMed) e de distribuição de potência por faixas (DPF) da densidade espectral de potência, as propriedades eletromiográficas dos músculos bíceps braquial (BB) e reto femoral (RF) de portadoras de DM2 com tempo de diagnóstico <5 anos, durante contração estática voluntária máxima (CEVM). Participaram do presente estudo seis pacientes DM2 (GDM2) e seis não diabéticas (GC), sedentárias, com idade e IMC semelhantes. Não foram observadas diferenças significativas para os valores de força durante a flexão do antebraço (21,3 ± 5,0 vs 22,9 ± 3,6 kgf) e a extensão da joelho (45,9 ± 14,5 vs 57,6 ± 15,3 kgf) entre o GDM2 e GC. No entanto, observou-se diferenças significativas para os valores de FMed (125,73 ± 14,9 Hz vs 158,17 ± 24,7 Hz para o sinal eletromiográfico do BB e 126,02 ± 8,1 Hz vs 148,18 ± 13,0 Hz para o sinal do RF, GDM2 e GC, respectivamente). Na investigação da DPF, diferenças significativas para a faixa de frequência entre 101 e 110 Hz do sinal eletromiográfico do BB e nas faixas entre 81 e 90 Hz e entre 91 e 100 Hz do sinal eletromiográfico do RF foram encontradas. Apesar de ainda não terem sido evidenciado comprometimentos estatisticamente significativos para os valores de força, diferenças significativas foram encontradas para os valores de FMed e DPF entre os grupo avaliados. Tais diferenças podem estar associadas, em parte, ao aumento da duração dos potenciais de ação das unidades motoras e o comprometimento na ativação de unidades motoras ativadas em faixas de frequência superiores. / The investigation of the electrophysiological properties of the neuromuscular system (NS) during the modulation of muscle strength has been studied in several areas. Among the techniques employed for this purpose is surface electromyography (sEMG). In the midst of pathological conditions that can potentially cause changes in the tissue and physiological properties of the SN, and hence the electrophysiological properties during the modulation of force, there is type 2 diabetes mellitus (T2DM). The aim of this study was to investigate, through the values of median frequency (MdF) and power distribution frequency (PDF) of the power spectral density, the electrophysiological properties of sEMG of the biceps brachii muscle (BB) and rectus femoris muscle (RF) of women with T2DM with time since diagnosis <5 years, during static maximum voluntary contraction (SMVC). The study included six patients DM2 (GDM2) and six nondiabetic (GC), sedentary, with similar age and body mass index (BMI). There were no significant differences in the values of SMVC during elbow flexion (21.3 ± 5.0 vs 22.9 ± 3.6 kgf) and knee extension (45.9 ± 14.5 vs 57.6 ± 15.3 kgf) between the GC and GDM2. However, we found significant differences in the values of MdF (125.73 ± 158.17 ± 14.9 Hz vs 24.7 Hz for the EMG signal of BB and 126.02 vs. 148.18 ± 8.1 Hz ± 13.0 Hz for the RF signal, and GDM2 GC, respectively). In investigating the DPF, significant differences in the frequency range between 101 and 110 Hz for sEMG of BB and the bands between 81 and 90 and between 91 Hz and 100 Hz of the sEMG of the RF were found. Although still not have been shown statistically significant for values of strength, significant differences were found for the values of MdF and DPF between the groups evaluated. Such differences may be related in part to the increased duration of action potentials of motor units and involvement in the activation of motor units activated at higher frequency bands.