999 resultados para mecanismos de cinemática plana
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INTRODUÇÃO: O movimento de alcance é muito estudado na literatura, no entanto, poucos estudos realizam análise cinemática e eletromiográfica desse movimento em sujeitos hemiparéticos. OBJETIVO: Avaliar o alcance de indivíduos hemiparéticos pós-acidente vascular encefálico (AVE) em seus aspectos cinemáticos e eletromiográficos. MATERIAIS E MÉTODOS: Foram selecionados quatro indivíduos, idade média de 54,5 ± 10,7 anos, com diagnóstico de AVE associado à hemiparesia. Realizou-se a avaliação cinemática e eletromiográfica concomitantemente do movimento de alcance na postura sentada, tanto do lado parético quanto do não parético. RESULTADOS: Houve diferença significativa entre os sujeitos com relação ao deslocamento (F(3,63) = 3.081, p = 0.03), porém, não ocorreu diferença significativa entre os lados (F(1,63) = 1.441, p = 0.23). Com relação às articulações (ombro, cotovelo e punho), houve diferença significativa entre os deslocamentos de cada uma (F(2,63) = 27.496, p = 0.00), assim como entre as coordenadas x, y e z (F(2,63) = 36.702, p = 0.00). Na análise dos dados eletromiográficos, não houve diferença significativa entre os sujeitos (F(3,31) = 2.437, p = 0.08), entre os lados (F(1,31) = 3.384, p = 0.07) e entre os músculos (F(4,31) = 0.942, p = 0.45). Existiu diferença no tempo de execução dos movimentos quando comparado o lado não acometido com o acometido. CONCLUSÃO: As análises cinemática e eletromiográfica, de um modo geral, mostraram resultados semelhantes aos encontrados na literatura. No entanto, este estudo acrescenta uma visão mais sistematizada do movimento de alcance, considerando seus aspectos funcionais, diferindo de outros estudos por apresentar, concomitantemente, análises cinemática e eletromiográfica e por investigar ambos os membros superiores.
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O músculo estriado esquelético é formado pela associação de fibras musculares com a matriz extracelular. Esse tecido possui alta plasticidade e o conhecimento das características morfológicas, da miogênese, e da dinâmica do crescimento é importante para o entendimento da morfofisiologia bem como para a seleção de animais visando a melhoria na produção de carne. A maioria dos músculos estriados originam-se de células precursoras do mesoderma a partir dos somitos do embrião e o controle da diferenciação ocorre pela ação de fatores indutores ou inibidores. Um grupo de fatores transcricionais, pertencentes à família MyoD tem um papel central na diferenciação muscular. Coletivamente chamados de Fatores de Regulação Miogênica (MRFs), são conhecidos quatro tipos: MyoD, myf-5, miogenina e MRF4. Esses fatores ligam-se à seqüências de DNA conhecidas como Ebox (CANNTG) na região promotora de vários genes músculo-específicos, levando à expressão dos mesmos. As células embrionárias com potencial para diferenciação em células musculares (células precursoras miogênicas) expressam MyoD e Myf-5 e são denominadas de mioblastos. Essas células proliferam, saem do ciclo celular, expressam miogenina e MRF4, que regulam a fusão e a diferenciação da fibra muscular. Uma população de mioblastos que se diferencia mais tardiamente, as células miossatélites, são responsáveis pelo crescimento muscular no período pós natal, que pode ocorrer por hiperplasia e hipertrofia das fibras. As células satélites quiescentes não expressam os MRFs, porém, sob a ação de estímulos como fatores de crescimento ou citocinas, ocorre a ativação desse tipo celular que prolifera e expressa os MRFs de maneira similar ao que ocorre com as células precursoras miogênicas durante a miogênese. Os mecanismos de crescimento muscular são regulados pela expressão temporal dos (MRFs), que controlam a expressão dos genes relacionados com o crescimento muscular.
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Purpose: To compare the safety and anti-inflammatory efficacy of a single posterior subtenon injection of triamcinolone acetonide (TA) with prednisolone acetate 1% eyedrops after pars plana vitrectomy (PPV).Methods: the study included 40 consecutive phakic eyes of 40 patients undergoing PPV for non-clearing vitreous haemorrhage with attached retina (verified by echography), epiretinal membrane or macular hole. At the end of the surgical procedure, eyes were randomized to receive either a single posterior subtenon injection of TA (40 mg in 1 ml) plus sham eyedrops (prednisolone acetate 1% vehicle) postoperatively (group TA), or a posterior subtenon sham injection (1 ml balanced salt solution) plus prednisolone acetate 1% eyedrops postoperatively (group ED).Results: There was no difference in the severity of anterior chamber cell and flare between the two groups at any time-point during the study period (p > 0.05). Separate within-group analysis revealed a significant decrease in anterior chamber cell and flare from postoperative day 1 to postoperative days 7, 14 and 28 in both groups (p < 0.05). There was no difference in pain, photophobia, conjunctival erythema, ciliary flush or chemosis scores between the two groups at any time-point during the study period (p > 0.05). Steroid-induced intraocular hypertension was not observed in either group.Conclusions: A single posterior subtenon injection of TA can be as effective and safe as a 4-week regimen of prednisolone acetate 1% eyedrops in controlling intraocular inflammation after PPV.
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The mechanisms involved in the absorption of amino acids and oligopeptides are reviewed regarding their implications in human feedings. Brush border and basolateral membranes are crossed by amino acids and di-tripeptides by passive (facilitated or simple diffusion) or active (Na + or H + co-transporters) pathways. Active Na +-dependent system occurs mainly at brush border and simple diffusion at basolateral, both membranes have the passive facilitated transport. Free-amino acids use either passive or active transport systems whereas di-tripeptides do mainly active (H + co-transporter). Brush border have distinctive transport system for amino acids and di-tripeptides. The former occurs mainly by active Na + dependency whereas the later is active H +-dependent with little affinity for tetra or higher peptides. Free amino acids are transported at different speed by saturable, competitive carriers with specificity for basic, acidic or neutral amino acids. Di and tripeptides have at least two carriers both electrogenic and H +-dependent. The basolateral membrane transport of amino acids is mostly by facilitated diffusion while for di-tripeptides it is an active anion exchange associated process. The main regulation of amino acids and di-tripeptide transport is the presence o substrate at the mucosal membrane with higher the substrate higher the absorption. Di and tripeptides are more efficiently absorbed than free amino acids which in turns are better absorbed than oligopeptides. So di-tripeptides result in better N-retention and is particularly useful in cases of lower intestinal absorption capacity. The non-absorbed peptides are digested and fermented by colonic bacteria resulting short-chain fatty acids, dicarboxylic acids, phenolic compounds and ammonia. Short-chain fatty acid provides energy for colonocytes and bacteria and the ammonia not fixed by bacteria returns to the liver for ureagenesis.
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This review aims to report the major control mechanisms of protein and peptides digestion of special interest in human patients. Regarding protein assimilation its digestive process begins at the stomach with some not so indispensable actions comparatively to those of duodenal/jejunal lumen. However even the intestine processes are partially under gastric secretion control. Proteolytic enzyme activities are related to protein structure and amino acid constituents, tertiary and quartenary structures need HCl - denaturation prior to enzymatic hydrolysis. Thereafter the exopeptidases are guided by either NH 2 (aminopeptidases) or COOH (carboxypeptidases) terminals of the molecule while endopeptidases are oriented by the specific amino acids constituents of the peptide. Both dietary and luminal secreted proteins and polypeptides undergo to either limited or complete proteolysis resulting basic or neutral free-amino acids (40%) or dioctapeptides. The brush border peptidases continue to degrade oligopeptide to di-tripeptides and neutral free-amino acids. Some peptides are uptaked by the enterocytes whose cytosolic peptidases complete the hydrolysis. Hence the digestive products flowing in the portal vein are mainly free-amino acids from either luminal or cytosolic hydrolysis and some di-tripeptides intactly absorbed. Both mechanical and chemical processes of digestion are under neural (vagal), neuroendocrinal(acetilcholine),endocrinal(gastrin, secretin and cholecystokinin) or paracrinal (histamine) controls. The gastric phase (hydrochloric acid and pepsinogen secretions) is activated by gastrin, histamine and acetilcholine which respond to both dietary-amino acids (tryptophan and phenylalanine) and mechanic distention of stomach. The pancreatic secretion is stimulated by either cephalic or gastric phases and has influence on the intestinal phase of digestion. The intestinal types of cells S and I release secretin and cholecystokinin respectively in response of acid quimo (cells S) or amino acids and peptides (cells I) in the lumen. Secretin stimulates the releasing of water, bicarbonate and enteropeptidases whereas cholecystokinin acts on pancreatic enzymes.
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Introduction. Gait becomes the individual independence for their daily activities. The functional deficit caused by central lesion as stroke, makes difficult this motor independence, mainly the locomotion. Objective. Analyze the kinematics gait in stroke patients. Method. It was included 8 patients with clinical diagnosis of stroke, 4 with hemiparesia on the right and 4 on the left. It was analyzed gait spatial-temporal parameters as: length, duration and average speed of the step, using the register in videotape and the software of image 6.3 Dvideow Barros. Results. All patients presented alterations in the kinematics standards of the gait, with lesser duration and length of step, and greater speed than normal subjects. Conclusion. The motor disorder caused by the central lesions produces alterations in the kinematics standards of the gait, in order to adapt the neuro-sensorial sequels, the demands of the task and the way where they live.
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Anterior cruciate ligament (ACL) injuries are common in sports. Studies investigating injury mechanisms have demonstrated that most injuries arise from landing tasks. Despite the demonstration of differences between male and female kinematics, there are no studies showing how males behave during different landing tasks. The objective of this study was to compare the angular and temporal kinematics of the lower limbs between two different landing tasks. Double leg and single leg landings were recorded in the frontal and sagittal plane in 15 male volleyball athletes by videogrammetry. Reduced hip and knee flexion and increased knee valgus were observed in the single leg landing task compared to the double leg landing task. No significant difference in landing time was observed between the two tasks. In conclusion, the results support the premise that lower limb kinematics change according to the task performed. Further studies are necessary to explore the impact of these kinematic differences on knee loading and to relate them to ACL injury mechanisms in men.
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