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Objective:To investigate the effects of beginning time of intermittent pneumatic compression (IPC) on hemodynamics and deep vein thrombosis (DVT) of patients with major orthopedic surgery.Methods:A total of 99 patients who underwent major orthopaedic surgery in the Department of Orthopaedics, West China Hospital, Sichuan University from January 2018 to December 2019 were selected as the research objects, which were assigned to ultra-early group, early group and control group, each group contained 33 cases. The IPC were used 3 days before surgery in the ultra-early group, 1 day before surgery in the early group, and after surgery in control group. The incidence of DVT and deep skin pressure injury within 14 days was observed, the blood flow velocity of deep femoral vein and plasma D-dimer in the three groups were also compared.Results:There was no significant difference in the incidence of DVT among the three groups ( P> 0.05), however, the deep tissue injury rate was 18.18% (6/33) in the ultra-early group, significantly higher than 3.03% (1/33) in the early group and 0 in control group, the difference was statistically significant ( χ2 value was 9.531, P<0.05). After 1 day and 3, 5, 7 days of surgery, the blood flow velocity of deep femoral vein in the ultra-early group and the early group were (26.48±2.24), (25.79±2.18), (26.67±3.74), (25.88±2.83) ml/s and (25.76±1.87), (25.39±1.98), (25.45±2.93), (25.48±3.75) ml/s, significantly higher than (23.39±1.75), (23.73±2.61), (23.79±2.30), (22.21±4.42) ml/s in the control group, the difference was statistically significant ( F values were 7.428-22.350, P<0.01). After 3, 5, 7 days of surgery, the levels of plasma D-dimer in the ultra-early group and the early group were (1.11±0.26), (1.03±0.23), (0.98±0.28) mg/L and (1.18±0.32), (1.12±0.24), (1.05±0.31) mg/L, significantly lower than (1.38±0.40), (1.32±0.39), (1.20±0.26) mg/L in the control group, the difference was statistically significant ( F values were 5.809, 8.442, 4.962, P<0.01). Conclusion:Using IPC one day before operation can significantly increase the blood flow velocity of deep femoral vein, reduce the level of plasma D-dimer, and do not increase the incidence of deep skin pressure injury in patients with major orthopedic surgery.
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Pressure ulcer is localized damage to the skin and subcutaneous tissue usually over a bony prominence as a result of prolonged pressure, shear force, and friction. The effect of external force on soft tissue is affected by many factors, such as local microenvironment, tissue blood supply, nutritional status, and underlying diseases of patients. Although great efforts have been made by mankind to prevent and treat pressure ulcer in last decades, its prevalence is still high, and the curative effect is still not impressive. The treatment of pressure ulcer is a challenge today, and it is necessary to seek new treatment methods. However, the prerequisite for exploring new treatment methods is to find a proper animal model and further explore new therapies through animal experiments. The pathogenesis of pressure ulcer is complex, and the formation process is affected by a variety of factors. To date, there is no recognized standard animal model. We review the pathogenesis of pressure ulcer and the recently reported animal models of pressure ulcer, so as to provide basic experimental basis for further research on the occurrence, development, and prevention of pressure ulcer.
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Objective:To set up the rat skeletal muscle L6 cell models of oxygen-glucose deprivation(OGD)in vitro,and to investigate the protective effect of EGF in deep tissue inj ury(DTI)of pressure sores.Methods:The rat skeletal muscle cells in the logarithmic phase were divided into normal control group,OGD group,5 μg·L-1 EGF+OGD group,10 μg·L-1EGF+ OGD group and 20 μg·L-1EGF+ OGD group.The survival rates of skeletal muscle cells in various groups were measured by MTT assay;the cell apoptotic rates in various groups were detected by flow cytometry;the reactive oxygen species(ROS)levels were detected by DCFH-DA;Rhodamine 123 was used to detect the mitochondrial membrane potential;the expressions of Bax and Bcl-2 proteins were determined by Western blotting method.Results:Compared with normal control group,the survival rates of skeletal muscle cells in OGD group after 24 h OGD was significantly decreased(P<0.05);the apoptotic rate was markedly increased(P<0.01);the ROS level was increased(P<0.01);the mitochondrial membrane potential was decreased(P<0.01);the ratio of Bcl-2/Bax was significantly decreased(P<0.01).Compared with OGD group, the survival rates of skeletal muscle cells in different concentrations of EGF groups were increased and the apoptotic rates were decreased,especially in 10 and 20 μg·L-1EGF groups(P<0.05 or P<0.01);the ROS levels in skeletal muscle cells in different concentrations of EGF groups were decreased and the mitochondrial membrane potential were increased,especially in 10 and 20 μg·L-1EGF groups(P<0.05 or P<0.01);the Bcl-2/Bax ratios were significantly decreased in a concentration-dependent manner,especially in 10 and 20 μg·L-1EGF groups (P<0.05 or P<0.01).Conclusion:EGF can improve the skeletal muscle cell injury induced by OGD in a concentration-dependent manner via decreasing the ROS levels and protecting the cell mitochondrial function.
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To set up the rat skeletal muscle L6 cell models of oxygen-glucose deprivation (OGD) in vitro, and to investigate the protective effect of EGF in deep tissue injury (DTI) of pressure sores. Methods: The rat skeletal muscle cells in the logarithmic phase were divided into normal control group, OGD group, 5 μg · L1 EGF+OGD group, 10 μg · L1 EGF+ OGD group and 20 μg · L1 EGF+ OGD group. The survival rates of skeletal muscle cells in various groups were measured by MTT assay; the cell apoptotic rates in various groups were detected by flow cytometry; the reactive oxygen species (ROS) levels were detected by DCFH-DA; Rhodamine 123 was used to detect the mitochondrial membrane potential; the expressions of Bax and Bel-2 proteins were determined by Western blotting method. Results: Compared with normal control group, the survival rates of skeletal muscle cells in OGD group after 24 h OGD was significantly decreased (P<0.05); the apoptotic rate was markedly increased (P<0.01); the ROS level was increased (P<0.01); the mitochondrial membrane potential was decreased (P<0.01); the ratio of Bcl-2/Bax was significantly decreased (P<0.01). Compared with OGD group, the survival rates of skeletal muscle cells in different concentrations of EGF groups were increased and the apoptotic rates were decreased, especially in 10 and 20 μg · L1 EGF groups (P<0.05 or P<0.01); the ROS levels in skeletal muscle cells in different concentrations of EGF groups were decreased and the mitochondrial membrane potential were increased, especially in 10 and 20 μg · L1EGF groups (P<0.05 or P<0.01); the Bcl-2/Bax ratios were significantly decreased in a concentration-dependent manner, especially in 10 and 20 μg · L1 EGF groups (P<0.05 or P<0.01). Conclusion: EGF can improve the skeletal muscle cell injury induced by OGD in a concentration-dependent manner via decreasing the ROS levels and protecting the cell mitochondrial function.
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AIM:To explore the role of Bcl-2 and PCNA expression in the injury of rat myoblasts induced by hydrogen peroxide (H2O2).METHODS:Rat myoblasts at growth phase were divided into 4 groups based on basic fibroblast growth factor (bFGF) and H2O2 levels:normal control group, bFGF group, model group (H2O2 group) and treatment group (bFGF+H2O2 group).The expression of Bcl-2 and Bax was observed by immunohistochemistry and fluorescence methods.The protein levels of Bax, Bcl-2 and PCNA were determined by Western blot.RESULTS:Compared with model group, both immunofuorescence and fluorescence in treatment group showed enhanced Bcl-2 and low expression of Bax.Furthermore, the results of Western blot showed up-regulated PCNA and Bcl-2 protein and decreased Bax expression in treatment group.CONCLUSION:Oxidative stress results in the pathologic changes of myoblasts, and the up-regulation of Bcl-2 and PCNA may attenuate myoblast injury.
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Las úlceras por presión son las complicaciones secundarias más comunes a una lesión medular, las cuales ponen en riesgo tanto la salud como la vida de quienes las padecen. Las úlceras por presión más comunes en lesionados medulares aparecen en la región pélvica, principalmente en las tuberosidades isquiáticas (TI's). Una estrategia usada en la clínica es medir la presión generada entre el paciente y la superficie donde se encuentra para evaluar el riesgo que representa dicha superficie para el desarrollo de úlceras por presión sin embargo, este tipo de mediciones superficiales no garantizan que la presión en los tejidos internos subyacentes a prominencias óseas sea inocua. Con el fin de estudiar los mecanismos de formación de úlceras por presión, se realizó el análisis de un modelo de pelvis y tejido subyacente por medio del Método de los Elementos Finitos (MEF). De esta manera se puede estudiar el comportamiento de las TI's sobre su tejido circundante, así como analizar los efectos biomecánicos que provocan las úlceras. Se construyó el modelo computacional por medio de un software de CAD (Computing Aided Design) de la pelvis a partir de cortes tomográficos. El modelo fue exportado al software COMSOL y se analizaron seis casos de estudio: un análisis de la pelvis sobre bloques de tejido sano y cinco casos más, los cuales simulan lesiones en el tejido con distintas profundidades, representando úlceras superficiales e internas. Los resultados mostraron que los puntos de máximo esfuerzo, en todas las pruebas, se localizan justo debajo de la TIs además se encontró que las lesiones internas presentan mayores esfuerzos y deformaciones, los cuales pueden ser precursores de daño en el tejido.
Pressure ulcers are the most common secondary complication to a spinal cord injury, which endanger both health and life of the patients who suffer them. The most common pressure ulcers in spinal cord injuries occur in the pelvic region, mainly in the ischial tuberosities (ITs). A strategy used in clinic is to quantify the pressure generated between the patient and the surface, in order to assess the risk posed by that surface for developing pressure ulcers. Despite this, this type of surface measurements does not guarantee that pressure in the internal tissues underlying to bony prominences, to be safe. In order to study the mechanisms of formation of pressure ulcers, an analysis of a model of the pelvis and its underlying tissue was performed using the Finite Element Method (FEM). By this means we can study the behavior of ITs on its surrounding tissue, and at the same time, we analyze the biomechanical effects those cause ulcers. The computational model of the pelvis was built from tomographic slices using CAD software (Computing Aided Design). The model was exported to the finite element software COMSOL and six study cases were analyzed: an analysis of the pelvis on healthy tissue blocks and five more cases, which simulate tissue injury with different depths, representing surface and internal ulcers. The results showed that the maximum stress points in all tests are located just below the ITs it was also found that internal injuries present higher stresses and strains, which can be precursors of tissue damage.
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Humans , Biomechanical Phenomena/physiology , Finite Element Analysis , Pressure Ulcer/physiopathology , Imaging, Three-Dimensional , Ischium/physiopathologyABSTRACT
Objective To compare the impacts of sustained and intermittent gradient pressure on perfusion disorders and myofiber injuries and to explore the mechanism by which intermittent gradient pressure helps treat deep tissue injury (DTI). MethodsTwenty Sprague-Dawley rats 10-12 weeks old were randomly divided into an experimental group and a control group.The tibialis anterior muscles of the experimental group received intermittent fluctuating pressure at 8.0-21.3 kPa while the control group received sustained pressure at 13.3 kPa.The contralateral notpressed muscles served as healthy controls.The experiment was terminated after 3 cycles of compression where each cycle involved 2 h of compression and 30 min of conpression release.The general condition of the rats'skin and muscles in the compressed region were observed and laser doppler perfusion imaging was used to detect blood perfusion of the skin of the compressed leg after 3 cycles of compression.Any pathomorphological changes in the tibialis anterior muscles of the compressed region were observed by phosphotungstic acid hematoxylin (PTAH) staining. Results Blood perfusion of the skin and muscle in the control group was significantly less than in the experimental group after compression,and blood flow velocity increased with time in both groups.However,perfusion was significantly more extensive in the experimental group.PTAH staining showed that muscle injury in the experimental group was significantly less severe than in the control group. ConclusionCompared to the sustained pressure,intermittent pressure cause significantly less severe DTI by reducing compression-induced ischemia and hypoxia.