Mechanical force has essential effects on cellular behaviors such as proliferation, migration and differentiation, and the mechanism of mechanotransduction is still one of the hot spots in mechanobiology study. Traditional methods could not provide accurate evaluation of the protein activation signal upon mechanical stress application. The development of fluorescence protein technology greatly promoted the understanding of mechanotransduction. In particular, genetically-encoded biosensors based on fluorescence resonance energy transfer (FRET) technique has achieved a real-time dynamic observation of living cell signal protein activity, which provides a powerful tool for the in-depth study of biomechanics. In this paper, we provide a summary on recent progress of FRET application in biomechanics. Firstly we introduce the FRET technology, and then we summarize three methods to integrate the mechanical stimulation with the FRET imaging system on cell experiments. After that, the important progress of biomechanical research on signal pathway made by FRET technology, such as cytoskeleton, Rho family, calcium and cellular physical stress visualization, are also discussed. Finally, we point out the bottleneck of the future development in FRET technology, and also make the prospect of the application of FRET in mechanotransduction. In summary, FRET technology provides a powerful tool for the studies of mechanotransduction, which will advance our systematic understanding on the molecular mechanisms about how cells respond to mechanical stimulation.
Biomechanical Phenomena ; Biosensing Techniques ; Fluorescence Resonance Energy Transfer ; Humans ; Luminescent Proteins ; chemistry ; Mechanotransduction, Cellular ; Microscopy, Fluorescence ; Signal Transduction ; Stress, Mechanical

In order to study neurotransmitter receptor regulation in the basal ganglia involved in the functional changes underlying levodopa-induced motor complications, quantitative autoradiography was used to observe receptor bindings of dopamine D1 and D2, N-methyl-D-aspartate (NMDA), amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA) and amino butyric acid (GABA) in the basal ganglia of rats that had unilateral nigrostriatal lesions and had been chronically treated with levodopa until motor complications developed. The rats were randomly assigned to three groups: normal, denervated and treatment-complicated groups. The results showed that response duration to levodopa became progressively shorter and abnormal involuntary movement (AIM) score was progressively increased during the course of levodopa treatment. Chronic treatment augmented D1 receptors more than denervation, and reduced D2 receptors that were also increased by dopamine denervation. Striatal NMDA receptors were substantially up-regulated in the treatment-complicated group. Levodopa treatment did not change receptors of nigral AMPA, pallidal GABA, and subthalamic GABA, which remained the same as that in denervation group. However, chronic treatment reversed the increase of nigral GABA receptors caused by the lesion. It was concluded that a shortening of response duration and AIM mimicked levodopa-induced motor complications of Parkinson's patients. These data suggested that up-regulation of dopamine D1 and NMDA receptors in the striatum leads to an imbalance of stimulation through the striatal output pathways, which is associated with levodopa-induced motor complications.

The silicone tube flow chamber system has been used to study the effects of wall shear stress and circumferential stress on the cultured vascular endothelial cells (ECs). In solviong the problem of how to precisely simulate the wall shear stress and circumferential stress to which ECs are subjected under physiological conditions, it is very essential to select not only the appropriate geometrical and mechanical characteristic but also the proper preload and after-load of the silicone tube flow chamber. Firstly, a method to obtain the geometrical and mechanical characteristic of the chamber was given. Secondly, the procedure to simulate the two main mechanical stimuli under the physiological environment was proposed. Finally, the factors controlling the wall shear stress and circumferential stress were summarized.
Arteries ; cytology ; Biomechanical Phenomena ; Blood Flow Velocity ; physiology ; Cell Culture Techniques ; instrumentation ; methods ; Cells, Cultured ; Endothelial Cells ; cytology ; Humans ; Mechanotransduction, Cellular ; physiology ; Shear Strength ; Silicones ; Stress, Mechanical

Objective To investigate the effects of hyperbaric oxygen (HBO) combined with neural stem cell (NSC) transplantation on functional recovery after spinal cord injury (SCI).Methods Forty healthy adult Sprague-Dawley rats were randomly divided into a sham group,an SCI group,an NSC group and an HBO+NSC group.In the latter three groups,complete spinal cord transection was performed at T10.The rats of the HBO+NSC group were treated with HBO therapy after NSC transplantation.Hindlimb motor function was assessed with the BassoBeattie-Bresnahan (BBB) scale and tilt table testing.Motor evoked potentials (MEPs) were measured to evaluate the rats'nerve conduction function.The amount of surviving transplanted NSCs at the injured site was counted using Hoechst dyeing.Results The average BBB scores and tilt table test results in the HBO+NSCs group were significantly better than in the SCI and NSC groups from the 2nd week post-SCI.By the 4th week the average latency period and MEP amplitude in the HBO+NSC group were significantly better than in the NSC group,while MEPs in the SCI group still had not re-appeared.The surviving amount of transplanted NSCs in the HBO+NSC group was also significantly greater than in the NSC group.Conclusion HBO combined with NSC transplantation has synergistic effects and can improve functional recovery after SCI.This may be explained by the important role of HBO in promoting the survival of transplanted NSCs.

In order to study neurotransmitter receptor regulation in the basal ganglia involved in the functional changes underlying levodopa-induced motor complications,quantitative autoradiography was used to observe receptor bindings of dopamine D1 and D2,N-methyl-D-aspartate (NMDA),amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA) and amino butyric acid (GABA) in the basal ganglia of rats that had unilateral nigrostriatal lesions and had been chronically treated with levodopa until motor complications developed.The rats were randomly assigned to three groups:normal,denervated and treatment-complicated groups.The results showed that response duration to levodopa became progressively shorter and abnormal involuntary movement (AIM) score was progressively increased during the course of levodopa treatment.Chronic treatment augmented DI receptors more than denervation,and reduced D2 receptors that were also increased by dopamine denervation.Striatal NMDA receptors were substantially up-regulated in the treatment-complicated group.Levodopa treatment did not change receptors of nigral AMPA,pailidai GABA,and subthalamic GABA,which remained the same as that in denervation group.However,chronic treatment reversed the increase ofnigral GABA receptors caused by the lesion.It was concluded that a shortening of response duration and AIM mimicked levodopa-induced motor complications of Parkinson's patients.These data suggested that up-regulation of dopamine D1 and NMDA receptors in the striatum leads to an imbalance of stimulation through the striatal output pathways,which is associated with levodopa-induced motor complications.

The ensemble empirical mode decomposition (EEMD) can be used to overcome the mode mixing problem of empirical mode decomposition (EMD) effectively. The EEMD method and Hilbert-Huang Transform (HHT) can be used to analyze pulse signals of Traditional Chinese Medicine (TCM). The amplitudes of the added white noise were about 0.1 and 0.2 time standard deviation of the investigated signal respectively. The difference of average frequency and average energy of every mode between normal pulse, slippery pulse, wiry pulse and wiry-slippery pulse were demonstrated based on different amplitudes of the added white noise. The results showed that it is more in line with clinical practice when the amplitude of the added white noise is about 0.2 time standard deviation of the investigated signal.
Algorithms ; Artifacts ; Diagnosis, Differential ; Humans ; Medicine, Chinese Traditional ; methods ; Pulse ; Signal Processing, Computer-Assisted

AIM: To explore the mechanism of Ginkgo biloba in the treatment of steroid-induced osteonecrosis of the femoral head based on network pharmacology. METHODS: The active ingredients and targets of Ginkgo biloba were predicted by the TCMSP, ADME, and PharmMapper databases. The disease targets related to steroid-induced osteonecrosis of the femoral head were searched by the GeneCards and OMIM databases. Cytoscape 3.6.1 was used to construct a protein-protein interaction network. The core target analysis, modular analysis, GO enrichment analysis, and KEGG pathway analysis of the targets of Ginkgo biloba in the intervention of steroid-induced osteonecrosis of the femoral head were performed by the STRING database. RESULTS: In this study, a total of 16 active ingredients of Ginkgo biloba and 547 targets were screened, of which 133 targets were related to steroid-induced femoral head necrosis. By PPI network topology analysis, TP53, AKT1, IL6, VEGFA, MAPK1, JUN, MAPK8, EGFR, EGF, and MYC were identified as the core targets. GO modularization analysis showed that these core targets were mainly related to apoptosis and angiogenesis. GO enrichment analysis was used to analyze the biological processes, cellular localization, and molecular functions of the core targets. KEGG enrichment analysis showed that the targets were mainly involved in molecular signaling pathways, among which the PI3K/AKT signaling pathway was the most relevant. CONCLUSION: Ginkgo biloba can inhibit steroid-induced osteonecrosis of the femoral head through multiple components, targets, and pathways, which provides the theoretical basis and reference for subsequent cell and animal experiments.

Objective:To investigate the effect of a degradable high-purity magnesium screw in fixing the greater trochanter bone flap of a lateral circumflex femoral artery transverse branch in the treatment of ischemic necrosis of femoral head in young and middle-aged adults.Methods:From February 2017 to February 2019, 12 cases (15 hips) of young and middle-aged patients with avascular necrosis of femoral head were treated in the Department of Orthopaedic of Affiliated Zhongshan Hospital of Dalian University. The age of patients was 30-53 years old. According to Association Research Circulation Osseous (ARCO), 2 hips were graded in stage II b, 4 in ARCO II c, 1 in ARCO III a, 5 in ARCO III b, 2 in ARCO III c and 1 in ARCO IV. The greater trochanter bone flap with a lateral circumferential vascular branch was used to fill the necrotic area, and fixed by a biodegradable high purity magnesium screw in the bone flap transfer. At 3, 6 and 12 months postoperation, the patient came to the hospital outpatient clinic for follow-up, and then were reviewed once a year. Imaging efficacy was evaluated by comparing preoperative and postoperative imaging. The Harris score and Visual Anoalogue Scale (VAS) score were tested at 12 and 24 months after surgery. The Harris score and VAS score before and after surgery were compared by Friedman test, and P<0.05 was considered statistically significant. Results:All 12 patients (15 hips) were entered in the 24-36 months of follow-up. At 12 and 24 months after surgery, Harris score was found at 87 (86, 92) and 90 (87, 92) respertively, which were both higher than that before surgery [59 (52, 74)] with a significant statistical difference ( Z=-3.743, Z=-4.473, P<0.05). However, there was no significant difference in Harris scores between 12 and 24 months after the surgery ( Z=-0.730, P>0.05). At the 12 and 24 months after surgery, VAS score was found at 3 (2, 3) and 2 (1, 3) respertively, which were both lower than that before surgery [6 (5, 6) ] with a significant statistical difference ( Z=-3.560, Z=-4.656, P<0.05). There was no statistical difference in VAS scores between 12 and 24 months after surgery ( Z=-1.095, P>0.05). X-ray and CT scan showed that the bone flaps healed well and the areas of osteonecrosis were repaired. Thirteen femoral heads were in good shape, and 2 femoral heads had further collapse of hips. No patients underwent joint replacement surgery at the time of last follow-up. Conclusion:Fixation of the greater trochanter flap of lateral circumflex femoral artery transverse branch with a degradable high-purity magnesium screw can ensure the healing of the flap at the implantation site and avoid the displacement and shedding of the flap. It is a new therapeutic option to treat the avascular necrosis of femoral head of young and middle-aged people.

The subpulmonary ventricular exclusion (Fontan) could effectively improve the living quality for the children patients with a functional single ventricle in clinical. However, postoperative Fontan circulation failure can easily occur, causing obvious limitations while clinically implementing Fontan. The cavopulmonary assist devices (CPAD) is currently an effective means to solve such limitations. Therefore, in this paper the
Algorithms ; Child ; Feedback ; Heart-Assist Devices ; Hemodynamics ; Humans ; Models, Cardiovascular