No description available.

Serotonin (5-HT) and noradrenalin (NA) increase persistent inward currents mediated by sodium and calcium channels on the dendrites of motoneurons. The ability of 5-HT and NA to modulate these channels depends on the distributions of 5-HT and NA synapses. Recent studies of the distribution of 5-HT and NA synapses on motoneurons innervating the neck muscle splenius reported that these synapses are rare on the somata and have a strong bias to dendrites with small diameters. It is unknown whether this distribution pattern represents a general principle of organization (1) for all motoneuron groups or (2) for all types of modulators. To address the first question, we have examined the distribution of 5-HT and NA synapses on flexor motoneurons, which unlike extensor motoneurons, are not able to generate self-sustained discharges known to involve the activation of persistent inward currents. To answer the second question, we have mapped the distribution dopamine (DA) synapses. The dendrites of motoneurons that innervate the neck flexor rectus capitis anterior (RCA) were stained. Synapses containing 5-HT, NA and DA were identified using immunohistochemical techniques. Observations based on five RCA motoneurons indicate that the average densities of 5-HT and NA contacts are 2.3 and 1.4 times less dense than the average densities of 5-HT and NA contacts on splenius motoneurons, respectively. Moreover, pairs of 5-HT contacts and pairs of NA contacts were found to be 3.0 and 1.8 times closer together on splenius compared to RCA motoneurons, respectively. These observations may reflect the inability of flexor motoneurons to generate self sustained discharges. Similar to splenius motoneurons, 5-HT and NA synapses were found to preferentially innervate dendrites with diameters less than 2 µm. Thus, 5-HT and NA synapses facilitate channels in regions where excitatory or inhibitory signals undergo the largest attenuations. DA synapses on the dendritic tree were sparse (0.2 and 0.1 contacts per 1000 µm2), suggesting that the actions of DA synapses are confined to local regions on the dendritic tree. These results highlight that motoneurons do not all share the same intrinsic properties, and the distribution of modulatory synapses have a crucial role in determining these properties. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2011-09-28 15:17:54.335

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.89-95).

Eight functionally identified group Ia muscle afferents from triceps surae or plantaris muscles were labeled intraaxonally with horseradish peroxidase (HRP) in seven adult cats. Subsequently, HRP was injected into two to six homonymous or heteronymous alpha-motoneurons per animal (total = 22), each identified by motor unit type and located near the site of afferent injection. The complete trajectories of labeled afferents were reconstructed, and putative synaptic contacts on HRP-labeled motoneurons were identified at high magnification. Dendritic paths from each contact were also mapped and measured. A total of 24 contact systems (the combination of a group Ia afferent and a postsynaptic motoneuron) were reconstructed, of which 17 were homonymous, and seven were heteronymous. Overall, homonymous contact systems had an average of 9.6 boutons, whereas heteronymous contact systems had an average of 5.9 boutons. The average number of boutons found on type S motoneurons in homonymous contact systems was smaller (6.4, range 3-17) than in systems involving types FF or FR motoneurons (FF: 10.4, range 4-18; FR: 11.3, range 4-32). Neither of these differences were statistically significant. In contrast to earlier reports, a majority (15/24) of contact systems included more than one collateral from the same Ia afferent. The complexity (number of branch points) in the arborization pathway leading to each contact (overall mean 8.4 +/- 3.3) was virtually identical in all contact systems, irrespective of the type of postsynaptic motoneuron. The three-dimensional distribution of group Ia contacts was not coextensive with the radially organized dendrites of motoneurons: Dendrites oriented in the ventromedial to dorsolateral axis had the fewest (8%) contacts, whereas rostrocaudal dendrites had the most (63%) contacts. Nevertheless, contacts were widely distributed on the motoneuron surface, with few on and near the soma (< or = 200 microns radial distance from the soma) or on the most distal parts of the tree (> or = 1,000 microns). The boutons in individual contact systems also showed wide spatial and estimated electrotonic distributions; only 3/24 systems had all contact located within a restricted spatial/electrotonic region. The relations between these anatomical results and existing electrophysiological data on group Ia synaptic potentials are discussed.

Foot problems are not only the most common but in general also the most severe of the diabetic complications. The age group 15-50 yrs in this study was chosen because these patients were considered to be at their most active age and were felt to require optimal foot function. 380 patients (96 %) participated, 78 % with Type 1, 20 % Type 2 and 1 % with secondary diabetes mellitus (DM) and 100 healthy controls. Only six patients had signs of peripheral ischaemia but half of the patients had deformities such as fallen forefoot arches and hammer toes. With sensory thresholds and clinical signs it was demonstrated that age, duration of DM and tall stature are major risk factors for diabetic neuropathy. Gender differences depend on differences in height. Dorsiflexion of the toes against resistance was used to test the function and volume of m.extensor digitorum brevis. When compared with measurements of sensory thresholds for vibration, perception and pain, it was found to be a valuable test for screening of distal motor neuropathy. To prevent worsening of foot deformities 266 patients with Type 1 DM were followed for 3 years. Those with the most pronounced deformities were fitted with custom-made insoles and had repeated examinations. Improvement was more common in patients with insoles compared to patients without insoles. Bone mineral density (BMD) was measured in nine patients with osteopathy in their feet and 18 controls. BMD was lower in L2-L3, but not in the proximal femur, implying osteopenia being a possible risk factor for distal osteopathy. Plaster cast treatment was used in 33 diabetic patients with severe foot ulcers who were selected because previous conservative treatment had been unsuccessful and they had been judged unsuitable for vascular surgery. The lesions healed in 19 patients. In conclusion, the main findings demonstrate the need for an increased awareness of early preventive foot care in young and middle-aged diabetic patients. / <p>S. 1-46: sammanfattning, s. 47-120: 6 uppsatser</p> / digitalisering@umu

Children with cerebral palsy and powerful whole body extensor spasms find sitting in a rigid seat uncomfortable and sometimes painful due to the large forces they apply to their constraints. They are usually unable to speak and communication is difficult. The spasms affect every aspect of their lives. This thesis describes the genesis of a new functional dynamic seat for children with severe whole body extensor spasms, and the novel method used to design it. This novel seat technology is known as ‘Whole Body Dynamic Seating’. The thesis describes the clinical need this seat addresses, and the design and technology context in which this research takes place. The user evaluation, observation, measurement, analysis and reasoning that led to a successful seat design are described in detail. Children with cerebral palsy sometimes have whole body spasms that mean they cannot be seated in conventional static seating that positions a child in a fixed posture. For this research the children were classified as functioning at Chailey Sitting Ability Level 1 and Gross Motor Functional Classification System Level V. Such children spend much of their time being held by a person, or lying on a mat, bed or pad. This results in difficulty with social engagement and physical functioning, particularly in school. This research created a seat that such children could sit in, providing a comfortable and functional seat for use in a home or school classroom environment. This seat was designed with the direct and essential involvement of disabled children, their parents, therapists, teachers and carers. The work is part of a larger programme of research into seating and support technology that will enhance a child’s ability to gain functional movement and communication skills that can be employed to enable the child’s free self expression and social participation. The research investigated means of supporting children with whole body extensor spasms through a progressive iterative method utilizing direct user evaluation of a series of prototypes incrementing in complexity and fidelity towards a fully functional physical seat. An iterative method was used to design, build and evaluate three dynamic seats. This method incorporated two new approaches to prototyping developed for the research programme in response to difficulties encountered in designing dynamic systems for children with highly complex neuromotor disability. Soft and Semi-soft prototyping and evaluation methods provided essential feedback on dynamic seating concepts that guided proposed solutions, without requiring costly and time-consuming manufacture. Video was used to create a record of the children’s movements and responses for subsequent analysis. Instrumentation was built into the seats to enable direct objective measurement of the reaction forces and seat movement caused by extensor spasms. This thesis presents several unique features created through this research programme: 1. Independent and virtually hinged anatomical dynamic thigh supports; 2. Independent anatomical dynamic foot supports; 3. A virtually hinged dynamic back support; 4. An anatomical dynamic head support concept. The final Whole Body Dynamic Seat was child-centred in its functionality and aesthetic design, and was favourably commented upon by parents, children and school staff. Use of the new dynamic seating by three children (including one from a previous work programme) showed that children with severe whole body extensor spasms can be seated comfortably. The children also demonstrated gains in physical and social function as a result of using the dynamic seats. The two fully independent dynamic seats made advances in comfort over static seating for children with whole body extensor spasms. One of the children especially liked the seat and resisted being put back into his usual seating. An adult with severe cerebral palsy and extensor spasms evaluated a dynamic foot support concept and reported very significant reductions in spasticity and pain, and gains in physical function. The Whole Body Dynamic Seats showed gains in postural symmetry and in hand and head function over the usual static seats when used by the children with spasms. These gains were reported by staff during long term evaluations and measured specifically during the final evaluation. Two children learned to control the movement of seats in which they were sat, and were able to control their posture and use that control to carry out functions such as switch pressing. Such learning through the use of dynamic seating by children with severe dystonic cerebral palsy and whole body extensor spasms has not previously been documented. The seats did not just affect the children - school staff were affected too. School staff working around the children in the dynamic seats were observed to be more inclusive towards the children, and to expect more interaction from them. The ability of the children to move altered staff expectations of their ability to participate and communicate. This new seating has improved the quality of life of the children that use it. Future implementation of this technology in commercially produced seating offers the possibility of similar gains to many more severely disabled children who are currently less comfortable and less functional than they need to be.

Submitted by Rebeka Godeiro (rebeka_carvalho@hotmail.com) on 2017-12-01T15:30:18Z No. of bitstreams: 1 DENILSON DA SILVA SANTOS - DISSERTAÇÃO PPCEMAT 2014.pdf: 2474671 bytes, checksum: e6b7578836f9267c2f04227449ea6331 (MD5) / Made available in DSpace on 2017-12-01T15:30:18Z (GMT). No. of bitstreams: 1 DENILSON DA SILVA SANTOS - DISSERTAÇÃO PPCEMAT 2014.pdf: 2474671 bytes, checksum: e6b7578836f9267c2f04227449ea6331 (MD5) Previous issue date: 2014-02-19 / CNPq / Neste estudo, foi avaliada a influência de um oligômero multifuncional de estireno-acrílico-epóxi (Joncryl - POLYAD PR 002), comercializado como extensor de cadeia para poliésteres, na compatibilização de misturas de poli(tereftalato de etileno) pós-consumo PET-PC/PEAD, obtidas a partir de PET pós-consumo (PET-PC) e poli(etileno de alta densidade) virgem (PEAD). Os efeitos do teor do extensor de cadeia e da sua combinação com o compatibilizante-polietileno modificado com anidrido maléico (PE-g-MA) nas interações das fases e nas características morfológicas das referidas misturas também foram investigados. Vários estudos sobre a compatibilização de misturas de PET/PEAD já foram reportados na literatura, contudo, pesquisas sobre o uso de extensores de cadeia a base de compostos epoxídos (Joncryl) para tal finalidade não foram reportadas até o momento, sendo este o primeiro trabalho que trata da compatibilização de misturas de PET pós-consumo-PET-PC/poli(etileno de alta densidade)-PEAD pelo uso de extensor de cadeia. As misturas PET-PC/PEAD foram processadas em um misturador interno acoplado ao reômetro de torque Haake Rheomix 3000QC da PolyLab QC operando com com rotores do tipo roller. Duas concentrações do extensor de cadeia (1,5 pcr e 3 pcr) e uma concentração do compatibilizante (10 pcr) foram avaliadas. As amostras obtidas foram caracterizadas por reometria de torque, onde a partir de medições de torque e temperatura obtidas pelo equipamento foi possível realizar uma avaliação das massas molares, e microscopia eletrônica de varredura (MEV). De acordo com os resultados, fica evidenciado que o uso do extensor de cadeia e da combinação compatibilizante-extensor resultou no aumento da massa molar da mistura e na compatibilização das misturas de PET-PC-PEAD. Contudo, o uso combinado de compatibilizante/extensor de cadeia mostrou-se mais efetivo na compatibilização do que o uso do extensor de cadeia utilizado isoladamente. A combinação compatibilizante/extensor de cadeia Joncryl poderá trazer benefícios para a reciclagem de misturas de PET pós-consumo e de PEAD – termoplásticos mais largamente encontrados nos lixões. / In this study, was evaluated the influence of a multifunctional styrene-acrylic-epoxy oligomer (Joncryl - POLYAD PR 002) marketed as a chain extender to polyester, in compatibility of blends of poly (ethylene terephthalate) PET/HDPE post market obtained from post-consumer PET (PC-PET) and virgin HDPE. The effects of chain extender content and its combination with the compatibilizer, polyethylene modified with maleic anhydride (PE-g-MA) in interactions of the phases and the morphology of these blends were also investigated. Several studies on the compatibilization of PET/HDPE blends have been reported in the literature, however, research on the use of the chain extenders based epoxy compounds (Joncryl) for this purpose has not been reported yet, which is the first study dealing with compatibilizing blends of post-consumer PET-PET-PC/poly (high density ethylene) - PEAD for the use of chain extender. The mixtures PET-PC/HDPE were processed in an internal mixer coupled to the torque rheometer Haake Rheomix 3000QC of PolyLab QC operating with roller type rotors. Two concentrations of the chain extender (1.5 pcr and 3 pcr) and a concentration of the compatibilizer (10 pcr) were evaluated. The samples obtained were characterized by torque rheometry and from torque and temperature measurements obtained by the equipment was possible to evaluate the molar masses. Samples were also characterized by scanning electron microscopy (SEM). According to the results, it is evident that the use of chain extender and the compatibilizer/chain extender combination resulted in increased molecular mass, and was effective in compatibilizing blends of HDPE-PET-PC. However the combined use of compatibilizer/chain extender was more effective in the compatibilization in comparation with the use of chain extender alone. The use of compatibilizer/Joncryl chain extender can bring benefits for the recycling of post-consumer PET and HDPE thermoplastic blends - more widely found dumpsters.

Determining tendon tension in the finger is essential to understanding forces that may be detrimental to hand function. Direct measurement is not feasible, making biomechanical modelling the best way to estimate these forces. In this study, the intrinsic muscles and extensor mechanism were added to an existing model of the index finger, and as such, it has been named the Intrinsic model. The Intrinsic model of the index finger has 4 degrees of freedom and 7 muscles (with 14 components). Muscle properties and paths for all extrinsic and intrinsic muscles were derived from the literature. Two models were evaluated, the Intrinsic model and the model it was adapted from (identified in this thesis as the Extrinsic-only model). To complement the model, multiple static optimization solution methods were also developed that allowed for EMG-constrained solutions and applied objective functions to promote co-contraction. To test the models and solution methods, 10 participants performed 9 static pressing tasks at 3 force levels, and 5 free motion dynamic tasks at 2 speeds. Kinematics, contact forces, and EMG (from the extrinsic muscles and first dorsal interosseous) were collected. For all solution methods, muscle activity predicted using the Intrinsic model was compared to activity from the model currently available through open-source software (OpenSim). Just by using the Intrinsic model, co-contraction increased by 16% during static palmar pressing tasks. The EMG-constrained solution methods gave a smaller difference between predicted and experimental activity compared to the optimization-only approach (p < 0.03). The model and solution methods developed in this thesis improve co-contraction and tendon tension estimates in the finger. As such, this work contributes to our understanding of the control of the hand and the forces that may be detrimental to hand function. / Thesis / Master of Science (MSc)

No description available.

Problemas relacionados a lesões de nervos periféricos com consequentes perdas sensitivas e motoras tornaram-se frequentes no dia a dia da prática clínica e hospitalar, em consequência do aumento da violência urbana, dos acidentes de trânsito, acidentes profissionais e domésticos. Por esta razão, a busca por estratégias e técnicas que possam reparar a lesão nervosa e restabelecer a função do tecido lesado é importante e de grande valia no âmbito da saúde. Para reparar lesões nervosas com perda de tecido nervoso, várias técnicas cirúrgicas têm sido utilizadas, uma das técnicas mais comum é o uso do enxerto autógeno, mas técnicas alternativas têm sido propostas a fim de evitar as complicações ao local doador e acelerar o processo de regeneração nervosa como, por exemplo, a da tubulização. O uso desta técnica tem sido mais utilizado para o preenchimento dos tubos com substâncias que acelerem ou induzam o crescimento axonal. Baseado no exposto anteriormente pensou-se na realização desta pesquisa com o objetivo de verificar se uso de tubo de polietileno poroso preenchido ou não com tecido adiposo na técnica de tubulização alteraria a recuperação dos músculos sóleo (de contração lenta) e Extensor longo dos dedos (de contração rápida). Para isso foram utilizados 45 ratos (Rattus norvegicus),Wistar, machos, que foram divididos em cinco grupos, sendo, três controles, e dois experimentais. Nos grupos experimentais foram realizados a tubulização de polietilieno poroso preenchido ou não com tecido adiposo (GECP e GESP, respectivamente). Os tubos foram testados para avaliar a eficácia em reduzir a lacuna crítica de 10 mm do nervo isquiático. Os animais dos grupos experimentais foram sacrificados 150 dias após a cirurgia. Dos três grupos controles, dois não sofreram intervenção cirúrgica, e receberam o nome de inicial (GCI) e final (GCF) e foram sacrificados com 80 e 230 dias de vida respectivamente. E no outro grupo controle, denominado desnervado (GCD) os animais foram submetidos à secção do nervo isquiático. Antes do sacrifício os animais foram submetidos à análise funcional da marcha. Durante o sacrifício foram retiradas amostras dos músculos sóleo e Extensor longo dos dedos, que foram submetidas à coloração de Hematoxilina e Eosina, Tricrômico de Masson, e também a reações de m-ATPase e NADH-Tr. Imunomarcações foi utilizada para a expressão de Myod e miogenina. Os dados foram submetidos ao tratamento estatístico. Os resultados mostraram que nos animais dos grupos experimentais tiveram melhor recuperação muscular do que os dos animais desnervados e foi inferior quando comparado com o grupo controle final (GCF). Baseado nestes dados pode-se concluir que o uso do tubo de polietileno poroso com preenchimento de tecido adiposo interferiu positivamente na recuperação tanto do músculo sóleo quanto o extensor longo dos dedos. / Problems related to injuries of peripheral nerves with consequent sensory and motor losses are seen more frequently in daily clinical and hospital practice due to an increase in urban violence, traffic accidents, domestic and labour accidents. For this reason, the search for strategies and techniques that can repair nerve damage and restore function of damaged tissue is important and of great value in health care. To repair nerve damage with loss of nerve tissue, several surgical techniques have been used, one of the common techniques is the use of the autograft, but alternative techniques have been proposed to avoid complications to the donor site and accelerate the process of nerve regeneration, such as tubulization. The use of this technique has been further utilized by filling the tubes with substances that speed up or induce axonal growth. Based on the previous work, in this research we wanted to see whether tubilization with the help of porous polyethylene tube filled with and without adipose tissue alter the recovery of the soleus (slow twitch) and extensor digitorum longus (fast twitch) muscles. For this we used 45 male Wistar rats (Rattus norvegicus), who were divided into five groups, three control and two experimental. In the experimental groups, tubulization was performed using porous polyethylene filled with (GECP) and without adipose tissue (GESP). The conduits were tested for efficacy in bridging the critical gap length of 10 mm in sciatic nerves.The animals of experimental groups were sacrificed 150 days after surgery. Of the three control groups, two did not undergo surgery, and were named as (GCI) for Initial and (GCF) for final group in which the animals were sacrificed at 80 and 230 days old respectively. And another control group, called denervated (GCD), the animals were subjected to sciatic nerve section. Prior to sacrifice the animals were subjected to functional analysis of gait. During the sacrifice, samples were taken from soleus and extensor digitorum longus muscles, which were stained with Hematoxylin and Eosin, Masson\'s trichrome and were also subjected to reactions of m-ATPase and NADH Tr. Immunostaining was also utilised for the expression of MyoD and myogenin. The data were analyzed statistically. The results showed that animals of experimental groups have better muscle recovery than those of denervated animals however the recovery was inferior when compared with the final control group (GCF).Based on these data we can conclude that the use of porous polyethylene tube filled with adipose tissue had a positive influence on the recovery of both the soleus and extensor digitorum longus.