Effects of therapeutic ultrasound on the mechanical properties of skeletal muscles after contusion

CONTEXTUALIZAÇÃO: O ultra-som terapêutico (UST) é um recurso comumente aplicado na aceleração do reparo tecidual de lesões musculares. A absorção das ondas ultra-sônicas é determinada pela freqüência e pela intensidade, sendo que, em uma mesma intensidade, a profundidade atingida por 1MHz é maior quando comparada a 3MHz. OBJETIVO: Analisar o comportamento das propriedades mecânicas de músculos submetidos à lesão aguda por impacto e tratados com UST, utilizando as freqüências de 1 e 3MHz. MATERIAIS E MÉTODOS: Foram utilizadas 40 ratas Wistar (200,1±17,8g), divididas em quatro grupos: (1) controle; (2) lesão muscular sem tratamento; (3) lesão muscular tratada com UST de freqüência 1MHz (0,5W/cm²) e (4) lesão muscular tratada com UST de freqüência 3MHz (0,5W/cm²). A lesão foi provocada no músculo gastrocnêmio por mecanismo de impacto. O tratamento foi de cinco minutos diários durante seis dias consecutivos. Os músculos foram submetidos a ensaios mecânicos de tração em uma máquina universal de ensaios. RESULTADOS: As médias e desvios-padrão das propriedades mecânicas dos grupos lesionados e tratados com UST foram significativamente maiores quando comparadas ao grupo lesionado sem tratamento (p<0,05). Em destaque, a propriedade de rigidez que, com a aplicação do UST, teve acréscimo de aproximadamente 38%. CONCLUSÕES: A intervenção, por meio do UST, promoveu aumento das propriedades mecânicas nos músculos lesionados aproximando-as do grupo controle. Entretanto, não foi observada diferença significativa entre as propriedades mecânicas dos grupos tratados com ultra-som de freqüências 1MHz e 3MHz.BACKGROUND: Therapeutic ultrasound is a resource commonly applied to speed up tissue repair in muscle injuries. The absorption of the ultrasound waves is determined by their frequency and intensity. For a given intensity, the depth reached by 1MHz is greater than the depth reached by 3MHz. OBJECTIVE: To analyze the mechanical properties of muscles subjected to acute impact injury treated with therapeutic ultrasound at the frequencies of 1 and 3MHz. METHODS: Forty female Wistar rats (200.1±17.8g) were used, divided into four groups: (1) control; (2) muscle injury without treatment; (3) muscle injury treated with therapeutic ultrasound at the frequency of 1MHz (0.5W/cm²); and (4) muscle injury treated with therapeutic ultrasound at the frequency of 3MHz (0.5W/cm²). The injury was produced in the gastrocnemius muscle by means of an impact mechanism. The treatment consisted of a single five-minute session per day, for six consecutive days. The muscles were subjected to mechanical traction tests in a universal test machine. RESULTS: Means and standard deviations for the mechanical properties of the injured groups that received therapeutic ultrasound were significantly greater than those of the injured group without treatment (p<0.05). The property of stiffness should be highlighted: the application of therapeutic ultrasound increased muscle stiffness by approximately 38%. CONCLUSIONS: Therapeutic ultrasound increased the mechanical properties of the injured muscles, and brought them to a level close to the control group. However, no significant difference in mechanical properties was observed between the groups treated with ultrasound at the frequencies of 1MHz and 3MHz

The relationship between foot arch measurements and walking parameters in children

BACKGROUND: Walking mechanics are influenced by body morphology. Foot arch height is one aspect of body morphology central to walking. However, generalizations about the relationship between arch height and walking are limited due to previous methodologies used for measuring the arch and the populations that have been studied. To gain the knowledge needed to support healthy gait in children and adults, we need to understand this relationship in unimpaired, typically developing children and adults using dynamic measures. The purpose of the current study was to examine the relationship between arch height and gait in a sample of healthy children and adults using dynamic measures. METHODS: Data were collected from 638 participants (n = 254 children and n = 384 adults) at the Museum of Science, Boston (MOS) and from 18 4- to 8-year-olds at the Motor Development and Motor Control Laboratories. Digital footprints were used to calculate two arch indices: the Chippaux-Smirak (CSI) and the Keimig Indices (KI). The height of the navicular bone was measured. Gait parameters were captured with a mechanized gait carpet at the MOS and three-dimensional motion analyses and in-ground force plates in the Motor Development and Motor Control Laboratories. RESULTS: Linear regression analyses on data from the MOS confirmed that as age increases, step length increases. With a linear mixed effect regression model, we found that individuals who took longer steps had higher arches as measured by the KI. However, this relationship was no longer significant when only adults were included in the model. A model restricted to children found that amongst this sample, those with higher CSI and higher KI values take longer relative step lengths. Data from the Motor Development and Motor Control Laboratories showed that both CSI and KI added to the prediction; children with lower anterior ground reaction forces had higher CSI and higher KI values. Arch height indices were correlated with navicular height. CONCLUSIONS: These results suggest that more than one measure of the arch may be needed elucidate the relationship between arch height and gait.K12 HD055931 - NICHD NIH HHS; K12HD055931 - NICHD NIH HH

Heterologous mesenchymal stem cells successfully treat femoral pseudarthrosis in rats

<p>Abstract</p> <p>Background</p> <p>This study evaluated the effectiveness of treating pseudarthrosis in rats by using bone marrow cell suspensions or cultures of bone marrow mesenchymal stromal cells</p> <p>Methods</p> <p>Thirty-eight specific pathogen-free (SPF) animals were randomly assigned to four groups: Group 1, Control, without surgical intervention; Group 2 (Placebo), experimental model of femoral pseudarthrosis treated only with saline solution; Group 3, experimental model of femoral pseudarthrosis treated with heterologous bone marrow cells suspension; Group 4, experimental model of femoral pseudarthrosis treated with cultures of heterologous mesenchymal stromal cells from bone marrow. When pseudarthrosis was confirmed by simple radiological studies, digital radiography and histopathology after a 120-day postoperative period, Groups 2, 3 and 4 were treated as above. At 30, 60 and 90 days after the treatment, all animals were evaluated by simple radiological studies, and at the end of the experiment, the animals were assessed by computed axial tomography and anatomopathological and histomorphometric examinations.</p> <p>Results</p> <p>Injected cells were detected in the areas affected by pseudarthrosis using scintigraphy within the first 24 hours after their administration. After 60 days, the animals of Group 3 showed callus formation while the animals of Group 4 presented periosteal reaction and had some consolidated areas. In contrast, Group 2 showed a predominance of fibro-osteoid tissue. After 90 days, bone consolidation and remodeling was observed in all animals from Group 3 whereas animals from Group 4 exhibited partial consolidation and those ones from Group 2 persisted with pseudarthrosis.</p> <p>Conclusion</p> <p>The treatment with heterologous bone marrow cells suspension proved to be effective in the treatment of pseudarthrosis whereas cultures of heterologous bone marrow mesenchymal stromal cells did not show the same potential to aid bone healing.</p