Myotonometry in machinery operators and its relationship with postural ergonomic risk.

OBJECTIVES: To analyze the association between occupational ergonomic risk, personal characteristics, and working conditions with the biomechanical properties of stiffness and muscular tone in the paravertebral muscles of electric pallet jack and forklift operators in the industrial sector. METHODS: A total of 75 industrial sector machine operators were evaluated in 2021. Personal characteristics and working conditions were assessed through a questionnaire. Ergonomic risk was assessed using the Rapid Entire Body Assessment (REBA) method, and biomechanical properties of stiffness and muscular tone were obtained using the Myoton Pro device. Stiffness in paravertebral muscles was compared based on the operated machine and observed ergonomic risk. A multilevel linear regression model was employed to quantify the relationship, with mean differences and 95% CI calculated. RESULTS: Very high ergonomic risk was found in 75% of the electric pallet truck drivers. In this group with the highest ergonomic risk, an association between biomechanical properties and older workers was observed. Additionally, among electric pallet truck drivers, stiffness (mean difference 335.9 N/m, 95% CI: 46.4 (3.4 to 110.0), P < 0.05) and paravertebral muscle tone (mean difference 17.5 Hz, 95% CI: 1.4 (0.1 to 3.4), P < 0.05) showed statistically significant differences in the very high ergonomic risk category compared to the high-risk category. No significant differences were observed in any of the analyzed variables among forklift drivers. CONCLUSIONS: Workers operating electric pallet trucks with very high ergonomic risk according to the REBA method and aged over 40 yr are associated with increased muscle stiffness and tone.

Long-term bisphosphonate treatment coupled with ovariectomy in mice provokes deleterious effects on femoral neck fracture pattern and modifies tibial shape.

AIMS: The processes linking long-term bisphosphonate treatment to atypical fracture remain elusive. To establish a means of exploring this link, we have examined how long-term bisphosphonate treatment with prior ovariectomy modifies femur fracture behaviour and tibia mass and shape in murine bones. METHODS: Three groups (seven per group) of 12-week-old mice were: 1) ovariectomized and 20 weeks thereafter treated weekly for 24 weeks with 100 µm/kg subcutaneous ibandronate (OVX+IBN); 2) ovariectomized (OVX); or 3) sham-operated (SHAM). Quantitative fracture analysis generated biomechanical properties for the femoral neck. Tibiae were microCT scanned and trabecular (proximal metaphysis) and cortical parameters along almost its whole length measured. RESULTS: Fracture analyses revealed that OVX+IBN significantly reduced yield displacement (vs SHAM/OVX) and resilience, and increased stiffness (vs SHAM). OVX+IBN elevated tibial trabecular parameters and also increased cortical cross-sectional area and second moment of area around minor axis, and diminished ellipticity proximally. CONCLUSION: These data indicate that combined ovariectomy and bisphosphonate generates cortical changes linked with greater bone brittleness and modified fracture characteristics, which may provide a basis in mice for interrogating the mechanisms and genetics of atypical fracture aetiology.Cite this article: Bone Joint Open 2020;1-9:512-519.

Effects of melatonin on the passive mechanical response of arteries in chronic hypoxic newborn lambs.

Chronic hypoxia is a condition that increases the cardiovascular complications of newborns gestated and born at high altitude (HA), over 2500 m above sea level (masl). A particularly complex pathology is pulmonary arterial hypertension of the neonate (PHN), which is increased at HA due to hypobaric hypoxia. Basic and clinical research have recognized that new treatments are needed, because current ones are, in general, palliative and with low effectiveness. Therefore, recently we have proposed melatonin as a potential adjuvant treatment to improve cardiopulmonary function. However, melatonin effects on the mechanical response of the arteries and their microstructure are not known. This study assesses the effects of a neonatal treatment with daily low doses of melatonin on the passive biomechanical behavior of the aorta artery and main pulmonary artery of PHN lambs born in chronic hypobaric hypoxia (at 3600 masl). With this purpose, ex-vivo measurements were made on axial stretch, tensile and opening ring tests together with a histological analysis to explore the morphometry and microstructure of the arteries. Our results show that the passive mechanical properties of the aorta artery and main pulmonary artery of lambs do not seem to be affected by a treatment based on low melatonin doses. However, we found evidence that melatonin has microstructural effects, particularly, diminishing cell proliferation, which is an indicator of antiremodeling capacity. Therefore, the use of melatonin as an adjuvant against pathologies like PHN would present antiproliferative effect at the microstructural level, keeping the macroscopic properties of the aorta artery and main pulmonary artery.

Reliability and sensitivity of an instrument for measuring the midfoot passive mechanical properties.

To assess the test - retest reliability and sensitivity of an instrument developed to measure the passive mechanical properties of the midfoot joint complex (MFJC), nine female and three male healthy young adults were evaluated in two different days by two experienced examiners. After proper participant positioning on the instrument, the left forefoot was passively moved from eversion (20°) to inversion (45°) at 2°/s, while the rearfoot and shank were kept immobile. From the instrument's sensing units (torque meter and potentiometer at 100 Hz), passive torque and angle data were registered. Passive stiffness was calculated as the instantaneous slope of the torque vs. angle curve. Therefore, the variables analyzed were resting angle, passive torques and stiffnesses during inversion and eversion through the intraclass correlation coefficient (ICC3,3), standard error of measurement (SEM) and minimal detectable change (MDC95). For the resting angle, ICC3,3 ranged from 0.85 to 0.91, SEM ranged from 1.54° to 1.95° and MDC95 ranged from 4.26° to 5.41°. For the torques, ICC3,3 ranged from 0.85 to 0.97, SEM ranged from 0.09Nm to 0.42Nm and MDC95 ranged from 0.26Nm to 1.16Nm. Finally, for the stiffnesses, ICC3,3 ranged from 0.79 to 0.98, SEM ranged from 0.01Nm/° to 0.04Nm/° and MDC95 ranged from 0.01Nm/° to 0.10 Nm/°. It can be concluded that most of the measurements presented good to excellent reliability with low measurement error. Hence, clinicians and researchers may benefit from the reliable and stable measures provided by the Foot Torsimeter when assessing patients and planning interventions.

Effects of Nutritional Deficiency of Boron on the Bones of the Appendicular Skeleton of Mice.

Scientific evidence has shown the nutritional importance of boron (B) in the remodeling and repair of cancellous bone tissue. However, the effects of the nutritional deficiency of B on the cortical bone tissue of the appendicular skeleton have not yet been described. Thus, a study was performed to histomorphometrically evaluate the density of osteocyte lacunae of cortical bone of mouse femora under conditions of nutritional deficiency of B and to analyze the effects of the deficiency on the biomechanical properties of mouse tibiae. Weaning, 21-day-old male Swiss mice were assigned to the following two groups: controls (B+; n = 10) and experimental (B-; n = 10). Control mice were fed a basal diet containing 3 mg B/kg, whereas experimental mice were fed a B-deficient diet containing 0.07 mg B/kg for 9 weeks. The histological and histomorphometric evaluations of the mice fed a B-deficient diet showed a decrease in the density of osteocyte lacunae in the femoral cortical bone tissue and the evaluation of biomechanical properties showed lower bone rigidity in the tibia.

Predissection-derived geometric and distensibility indices reveal increased peak longitudinal stress and stiffness in patients sustaining acute type A aortic dissection: Implications for predicting dissection.

OBJECTIVE: To assess ascending aortic distensibility and build geometry and distensibility-based patient-specific stress distribution maps in patients sustaining type A aortic dissection (TAAD) using predissection noninvasive imaging. METHODS: Review of charts from patients undergoing surgical repair of TAAD (n = 351) led to the selection of a subset population (n = 7) with 2 or more predissection computed tomography angiography scans and echocardiograms at least 1 year before dissection. Ascending aortic wall biomechanical properties (aortic strain, distensibility, and stiffness) were compared with age- and size-matched nondissected nonaneurysmal controls. Patient-specific aortic strain served as an input in aortic geometry-based simulated 3-dimensional reconstructions to generate longitudinal and circumferential wall stress maps. Inspection of perioperative dissection scans and intraoperative visual examination confirmed primary tear locations. RESULTS: Predissection echocardiography revealed ascending aortas of patients sustaining TAAD to exhibit decreased aortic wall strain (14.50 ± 1.13% vs 8.49 ± 1.08%; P < .01), decreased distensibility (4.26 ± 0.44 vs 2.39 ± 0.33 10-6 cm2·dyne-1; P < .01), increased stiffness (3.84 ± 0.24 vs 7.48 ± 1.05; P < .001), and increased longitudinal wall stress (246 ± 22 vs 172 ± 37 kPa; P < .01). There was no significant difference in circumferential wall stress. Predissection computed tomography angiography models revealed overlap between regions of increased longitudinal wall stress and primary tear sites. CONCLUSIONS: Using predissection imaging, we identified increased stiffness and longitudinal wall stress in ascending aortas of patients with dissection. Patient-specific imaging-derived biomechanical property maps like these may be instrumental toward designing better prediction models of aortic dissection potential.

Flaxseed (linum usitatissimum) flour contributes to bone health in adult male rats.

OBJECTIVE: This study evaluated effects of flaxseed flour diet on bone health in adult Wistar male rats at 180 d. METHODS: After birth, pups were randomly assigned: Control (C, n = 12) and flaxseed flour (FF, n = 12) diet during lactation period. At 21 d, pups were weaned and they continued to receive the control and experimental diet, respectively. At 180 d, body length, total bone structure, and femur and lumbar vertebrae were evaluated by dual-energy X-ray absorptiometry. Femoral and lumbar vertebra dimensions, biomechanical properties of femur, and serum osteocalcin were measured. RESULTS: FF produced greater (P <0.05) total (+3.4%) and spine (+5.9%) bone mineral density, total (+10%) and spine (+12%) bone mineral content, total bone area (+8.7%), and osteocalcin (+82%). As to femur, FF produced greater (P <0.05) width of diaphysis (+8.1%), bone mineral density (+5.2%), maximum force (+10.6%), breaking strength (+12.9%), and stiffness (+23%). CONCLUSION: This experimental study found that a diet containing flaxseed flour contributed to bone mineral density and femur resistance at 180 d.

Biomecánica corneal y glaucoma / Corneal biomechanical properties and glaucoma

Este trabajo tiene como objetivo conocer los avances más novedosos relacionados con el estudio de las características biomecánicas de la córnea y su posible relación en el diagnóstico del glaucoma. Se realizó una búsqueda en la plataforma Infomed, específicamente en la Biblioteca Virtual de Salud, con el objetivo de conocer los avances más novedosos relacionados con el estudio de las características biomecánicas de la córnea y su posible relación en el diagnóstico del glaucoma. La biomecánica corneal es la facultad de resistencia y flexión simultánea de las moléculas de colágeno en las diferentes capas de la córnea. Trata del equilibrio y de la deformación del tejido corneal sometido a cualquier acción exterior. La histéresis corneal, junto con el factor de resistencia corneal, son medidas que pueden ser proporcionadas por el analizador de respuesta ocular. La existencia de un bajo valor de estas dos medidas pudiera considerarse como un factor de riesgo de progresión en el glaucoma(AU)

The purpose of this work is to know the more novel advances related with the study of the biomechanic characteristic of the cornea and its possible relationship in the diagnosis of the glaucoma. A search was made in Infomed platform, particularly in the Virtual Library of Health, to find out the most advanced in the study of the corneal biomechanical properties and its possible relation with the diagnose of glaucoma. Corneal biomechanical is the power of the resistance and flexion simultaneity of collagen molecules of the different corneal layer. It is the balance and deformity of the corneal tissue submitted to an external action. Corneal hysteresis and corneal resistance factor are two corneal biomechanical properties measured by the Ocular Response Analyzer. The existence of a low value of these two properties may be considered as progression factors in glaucoma(AU)

Exploratory factor analysis for differentiating sensory and mechanical variables related to muscle-tendon unit elongation

ABSTRACT Background Stretching exercises are able to promote adaptations in the muscle-tendon unit (MTU), which can be tested through physiological and biomechanical variables. Identifying the key variables in MTU adaptations is crucial to improvements in training. Objective To perform an exploratory factor analysis (EFA) involving the variables often used to evaluate the response of the MTU to stretching exercises. Method Maximum joint range of motion (ROMMAX), ROM at first sensation of stretching (FSTROM), peak torque (torqueMAX), passive stiffness, normalized stiffness, passive energy, and normalized energy were investigated in 36 participants during passive knee extension on an isokinetic dynamometer. Stiffness and energy values were normalized by the muscle cross-sectional area and their passive mode assured by monitoring the EMG activity. Results EFA revealed two major factors that explained 89.68% of the total variance: 53.13% was explained by the variables torqueMAX, passive stiffness, normalized stiffness, passive energy, and normalized energy, whereas the remaining 36.55% was explained by the variables ROMMAX and FSTROM. Conclusion This result supports the literature wherein two main hypotheses (mechanical and sensory theories) have been suggested to describe the adaptations of the MTU to stretching exercises. Contrary to some studies, in the present investigation torqueMAX was significantly correlated with the variables of the mechanical theory rather than those of the sensory theory. Therefore, a new approach was proposed to explain the behavior of the torqueMAX during stretching exercises.

Characterization and Short-Term clinical study of clay facial mask / Caracterização e estudo clínico de curta duração de máscara facial argilosa

Clay mineral facial masks are used to treat some dermatological diseases, just for cleansing or reduce the amount of oil secreted by sebaceous glands. There are several types of clays, which vary in mineralogical and chemical composition, color and origin. However, the literature lacks studies involving clay facial masks, in particular regarding their influence on skin´s biomechanical properties. Thus, this work aimed to characterize colored clays and evaluate its influence on skin frmness and elasticity by a short-term clinical study. Different clays (named in this study magnesium aluminum silicate - MAS, white, pink and green) were chemically characterized, and facial mask formulations were prepared. The short-term clinical study was performed through the application of formulations on the skin. The skin frmness and elasticity were assessed before treatment and after mask removal. The statistical analysis showed no signifcant influence of time or formulations in those parameters, although volunteers reported the sensation of mechanical tension after the removal of the clay facial masks. Thus, the composition of the different clays did not affect the skin viscoelasticity behavior in the short-term clinical study, and a long-term use of this type of formulation must be indicated to observe all the expected benefts.(AU)

Máscaras faciais argilosas são utilizadas para tratar algumas doenças dermatológicas, apenas para a limpeza ou reduzir a quantidade de óleo secretado pelas glândulas sebáceas. Existem vários tipos de argilas, que variam em composição mineral, química, cor e origem. No entanto, a literatura carece de estudos envolvendo máscaras faciais argilosas, em particular em relação a sua influência nas propriedades biomecânicas da pele. Assim, este trabalho teve como objetivo caracterizar argilas coloridas e avaliar sua influência sobre a frmeza e elasticidade da pele por meio de um estudo clínico de curto prazo. Diferentes argilas (chamadas neste estudo de silicato de alumínio e magnésio - MAS, branca, rosa e verde) foram caracterizadas quimicamente, e formulações de máscaras faciais foram preparadas. O estudo clínico de curto prazo foi realizado por meio da aplicação das formulações na pele. A frmeza e elasticidade da pele foram avaliadas antes do tratamento e após a remoção da máscara. A análise estatística mostrou nenhuma influência signifcativa do tempo ou das formulações nesses parâmetros, embora os voluntários tenham reportado sensação de tensão mecânica, após a remoção das máscaras faciais argilosas. Assim, a composição das diferentes argilas não afetou o comportamento visco-elástico da pele no estudo clínico de curto prazo, e uma utilização de longa duração poderia ser indicada com a fnalidade de se observar todos os benefícios esperados.(AU)

Estudo da correlação instrumental e sensorial de uma composição aromática aplicada na pele em função do ciclo menstrual / Study of instrumental and sensory correlation of a aromatic composition on the skin in function of mentrual cycle

A área de perfumaria no mundo vem se desenvolvendo a cada dia buscando maior conhecimento das matérias-primas aromáticas, desde suas reações, estabilidade até suas interações com o substrato onde é aplicado, sempre em busca do conhecimento de todas as variáveis que possam influenciar a relação perfume-substrato e a aceitação dos consumidores, medida por meio da avaliação sensorial. Apesar de muitos estudos sobre a relação perfume-pele, poucos envolveram a relação com ciclo menstrual. Neste estudo o objetivo foi correlacionar às análises sensorial e instrumental (medidas biomecânicas e cromatográficas), estudar as matérias-primas aromáticas em função do ciclo menstrual. O estudo envolveu indivíduos com idade entre 18-40 anos: 29 mulheres e 3 homens, estes usados como grupo controle. Cada voluntária teve 40 µl da composição aromática Ciclo 1910 aplicado no antebraço, onde foram feitas as medidas biomecânicas (corneometria, sebumetria e TEWL) nos tempos inicial e 6h. Nos tempos inicial, 1.5h, 3h, 4,5h e 6h se auto-avaliaram sensorialmente a intensidade de perfume por meio de escala sensorial de magnitude rotulada (LMS) e foram coletados os compostos aromáticos liberados pela técnica de headspace e analisados por espectrometria com cromatografia a gás e detetor de massa (CGMS). Realizou-se também medidas biomecânicas de corneometria, sebumetria e TEWL interescapulares em 5 voluntárias nos tempos inicial e 6h para comparação. Os resultados obtidos foram que as fases do ciclo não interferiram nas variáveis biomecânicas (p>0,05) quando analisadas isoladamente. Para as medidas realizadas no antebraço, os índices de Corneometria (p<0,001) e TEWL (p: 0,011) na região tratada apresentou média maior que a do controle. A média dos índices de Corneometria e Sebumetria da região do antebraço tratada foi menor (p<0,001) que da região interescapular. Na análise cromatográfica não houve um padrão de resposta em diferentes fases do ciclo. As correlações entre a avaliação sensorial e instrumental (cromatografia e propriedades biomecânicas) não observaram nenhum nível de correlação (p>0,05). A Cromatografia (dados cromatográficos) foi maior na fase Folicular que nas fases Menstrual e Ovulatória (p=0,003), ao considerar como variável resposta em função do ciclo menstrual e da avaliação sensorial. Houve uma forte correlação positiva entre a análise sensorial e a avaliação na pele do homem (p<0,001). No entanto, o fator intrínseco do indivíduo Mulher influenciou na resposta, ocasionando grande variabilidade, porém percebeu-se claramente que os hormônios sexuais interferiram na resposta sensorial, cromatográfica e biomecânica da pele

The perfumery in the world has been developed everyday bringing more knowledge about aromatic raw-materials, as from chemistry reactions, stability until their interactions with substrate where is applied, always looking for variables could influence in the relation perfume-substrate and consumer acceptability, measured by sensory evaluation. Despite a lot of studies were done on this subject, few involved effects as function of menstrual cycle. The aim of this study was to correlate sensory and instrumental analysis (biomechanical and chromatographic measurements), to study the olfactory profile of raw materials in function of menstrual cycle. The study involved people with 18-40 years old: 29 volunteers, three men, who were used as control group. Each volunteer had 40 µl of perfume applied on forearm, where were done Biomechanical measurements (Corneometer, Sebumeter and TEWL) at initial and 6h, At time initial, 1.5h, 3h, 4.5h and 6h; they did self-sensory assessment in perfume intensity in own forearm using labeled magnitude scale (LMS) and also where aromatic compounds released were collected by headspace technique spectrometry and gas chromatography with mass detector (CGMS). In addition, it was done biomechanical measurements (Corneometer, Sebumeter and TEWL) on interscapular region at initial and 6h for comparing. Resulting that the phases of the cycle did not affect the biomechanical variables (p > 0.05) when analyzed individually. For measurements in the forearm, Corneometry index (p < 0.001) and TEWL (p=0.011) in the treated area were higher than the control. The average of the Sebumetry, Corneometry indexes of the forearm treated was lower (p <0.001) than the interscapular region. In the analysis of chromatographic, there was a standard response at different stages of the menstrual cycle, however the analysis by individual had no a pattern response to the release of aromatic compounds. The correlations between sensory and instrumental (chromatography and biomechanical properties) did not observe any correlation (p> 0.05). But when considering chromatography as the response variable as a function of the menstrual cycle and the sensory evaluation, the follicular phase was higher than the Menstrual and Ovulatory phase (p=0.003). There was a strong positive correlation between sensory analysis and evaluation on men skin (p<0.001). However, the intrinsic factor of the individual woman influenced the response, leading to large response variability; however, see clearly that sex hormones interfere in the sensory response, chromatographic and biomechanics of the skin

Hipertensão ocular mascarada por edema de córnea após cirurgia da catarata / Ocular hipertension confounded by corneal edema after cataract surgery

Com base em modelos matemáticos e estudos experimentais estima-se que as medidas da PIO sejam linearmente hiperestimadas em córneas com maior espessura e menor ceratometria por meio de tonometria de aplanação de Goldmann (TAG). Entretanto, tal influência se dá de uma maneira mais complexa que a prevista por estes parâmetros geométricos, sendo diretamente relacionada com propriedades biomecânicas. O sistema de não contato ORA (Ocular response analyzer Reichert) permite estudo das propriedades biomecânicas juntamente com a medida pressórica calibrada para a TAG e a compensada da córnea. Adicionalmente, o estudo tomográfico com reconstrução tridimensional do mapa paquimétrico caracteriza a córnea de forma mais completa que a ceratometria anterior e espessura central. Neste artigo, relatamos um caso de dor ocular, fotofobia e baixa visão, 28 dias após cirurgia de facoemulsificação com implante de lente intraocular sem complicações em paciente feminina de 81 anos. Na primeira visita da paciente, enquanto a TAG era de 16 mmHg, o valor da PIO compensada da córnea (PIOcc), obtido com o ORA, era 25,6 mmHg. A histerese e fator de resistência da córnea eram baixos, 4,1 e 6,1mmHg respectivamente, apesar da paquimetria central ser relativamente mais elevada, de 601 micra. O padrão de distribuição espacial da espessura era atenuado, compatível com edema corneano que era observado também por meio das imagens de Scheimpflug (Pentacam). Com base nestes dados, foi feito diagnóstico de quadro de uveíte hipertensiva, associado à edema corneano, instituindo-se tratamento tópico com combinação fixa de maleato de timolol e brimonidina associado ao acetato de prednisolona. Três semanas após, a paciente apresentou-se com grande melhora da acuidade visual, resolução do edema corneano, e dos sintomas, normalizando os parâmetros biomecânicos, geométricos da córnea e de PIO.

Goldmann applanation tonometry (GAT) overestimates intraocular pressure (IOP) measurements in cases with thick and flatter corneas. This is thought to occur linearly based on mathematical and on experimental studies. However, such influence does exist, but this is more complex than the one anticipated by pachymetry and keratometry because it is related to corneal biomechanical properties. The ocular response analyzer (ORA Reichert) provides the data related to the biomechanical properties of the cornea along with the IOP measurements that are calibrated for correlating to the Goldmann applanation and also compensated from corneal properties. Also corneal tomography with a pachymetric map evaluation characterizes the cornea beyond central thickness and anterior curvature. In this article, we report a case of a 77 years old female patient with low vision, photofobia and ocular pain 28 days after phacoemulsification and intraocular lens implant. In the first visit, GAT was 14mmHg, while IOPcc (ORA corneal compensated IOP) was 25,6mmHg. Corneal hysteresis and resistance factor were low: 4,1 and 6,1mmHg respectively despite a central thickness of 601 micron. Corneal thickness spatial profile was attenuated with an edematous pattern that was also observed by the Scheimpflug images (Pentacam). Hypertensive uveitis was diagnosed and the patient was started on a fixed combination of timolol and brimonidine associate with prednisolone acetate. Three weeks after, the patient referred resolution of photofobia and marked improvement of vision. Clinically, edema was resolved as observed by corneal tomographyc and biomechanical findings.

Efeitos do ultra-som terapêutico nas propriedades mecânicas do músculo esquelético após contusão / 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 por cento. 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 percent. 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.

Snake venom derived fibrin adhesive in dog uterine healing: biomechanical study

Healing is a complex process with many interfering factors. The objective of this work was to evaluate regeneration strength of non-pregnant adult dog uterus when snake venom derived fibrin adhesive is used to reinforce hysterorrhaphy. Maximum limit and rigidity were analyzed. Twenty uterine horns from 10 dogs were hysterotomized and distributed into 2 equal groups. Hysterorrhaphy was performed using the Shimieden-Cushing double layer suture. In one group, animals received snake venom derived fibrin adhesive as reinforcement. Although neither variable was significantly different, our results showed higher rigidity values in the adhesive group. This can be attributed to the adhesives effect on organ elasticity or to more granulation tissue formed in the uterine scar.