A Rapid Non-invasive Method for Skin Tumor Tissue Early Detection Based on Bioimpedance Spectroscopy / 生物化学与生物物理进展

ObjectiveIn recent years, with the intensification of environmental issues and the depletion of ozone layer, incidence of skin tumors has also significantly increased, becoming one of the major threats to people’s lives and health. However, due to factors such as high concealment in the early stage of skin tumors, unclear symptoms, and large human skin area, most cases are detected in the middle to late stage. Early detection plays a crucial role in postoperative survival of skin tumors, which can significantly improve the treatment and survival rates of patients. We proposed a rapid non-invasive electrical impedance detection method for early screening of skin tumors based on bioimpedance spectroscopy (BIS) technology. MethodsFirstly, we have established a complete skin stratification model, including stratum corneum, epidermis, dermis, and subcutaneous tissue. And the numerical analysis method was used to investigate the effect of dehydrated and dry skin stratum corneum on contact impedance in BIS measurement. Secondly, differentiation effect of different diameter skin tumor tissues was studied using a skin model after removing the stratum corneum. Then, in order to demonstrate that BIS technology can be used for detecting the microinvasion stage of skin tumors, we conducted a simulation study on the differentiation effect of skin tumors under different infiltration depths. Finally, in order to verify that the designed BIS detection system can distinguish between tumor microinvasion periods, we conducted tumor invasion experiments using hydrogel treated pig skin tissue. ResultsThe simulation results show that a dry and high impedance stratum corneum will bring about huge contact impedance, which will lead to larger measurement errors and affect the accuracy of measurement results. We extracted the core evaluation parameter of relaxed imaginary impedance (Zimag-relax) from the simulation results of the skin tumor model. When the tumor radius (Rtumor) and invasion depth (h)>1.5 mm, the designed BIS detection system can distinguish between tumor tissue and normal tissue. At the same time, in order to evaluate the degree of canceration in skin tissue, the degree of tissue lesion (εworse) is defined by the relaxed imaginary impedance (Zimag-relax) of normal and tumor tissue (εworse is the percentage change in virtual impedance of tumor tissue relative to that of normal tissue), and we fitted a Depth-Zimag-relax curve using relaxation imaginary impedance data at different infiltration depths, which can be applied to quickly determine the infiltration depth of skin tumors after being supplemented with a large amount of clinical data in the future. The experimental results proved that when εworse=0.492 0, BIS could identify microinvasive tumor tissue, and the fitting curve correction coefficient of determination was 0.946 8, with good fitting effect. The simulation using pig skin tissue correlated the results of real human skin simulation with the experimental results of pig skin tissue, proving the reliability of this study, and laying the foundation for further clinical research in the future. ConclusionOur proposed BIS method has the advantages of fast, real-time, and non-invasive detection, as well as high sensitivity to skin tumors, which can be identified during the stage of tumor microinvasion.

Yun shou tai chi with visual feedback can improve the balance of stroke survivors / 中华物理医学与康复杂志

Objective:To observe any effect of Yun shou tai chi training with visual feedback on the balance of persons who have survived a stroke.Methods:Fifty-six stroke survivors were randomly divided into an observation group and a control group, each of 28. Both groups were given routine balance function training, while the observation group was additionally given Yun shou tai chi training with visual feedback. Before and after the four weeks of training, the subjects′ balance and posture were evaluated using a Nomex visual feedback balance system. Lower limb strength was evaluated with a microFET2 portable muscle strength tester. The Berg Balance Scale (BBS), Timed Up and Go Test (TUGT), 10-metre walk times (10MWTs) and the modified Barthel Index (MBI) were also applied.Results:After the training the average BBS, TUGT, 10MWT and MBI results of the observation group had improved significantly. Among the control group only TUGT times and MBI scores had improved significantly, but even then the average MBI score of the observation group was significantly higher. The training improved the strength of the trainees′ quadriceps femoris (QUA), tibialis anterior (TA) and gastrocnemius (GAS) on the hemiplegic side. Their hamstrings and GAS on the non-hemiplegic side were also significantly stronger, on average. The improvement in the QUA of the hemiplegic side in the observation group was significantly better than the control group′s average improvement. The path length (PL) and the covered area (CA) in the observation group had decreased significantly after the training, while among the controls only the CA had decreased significantly. The average PL in the observation group was therefore significantly shorter than in the control group.Conclusion:Yun shou tai chi training with visual feedback can promote the recovery of balance function after a stroke. Such training is worthy of clinical promotion and application.

The role of stem cell-derived exosomes in repairing myocardial injury / 生理学报

At present, it is generally believed that the paracrine effect of stem cells in the repair of myocardial injury is one of the important ways for stem cell therapy. Exosomes are phospholipid bilayer-enclosed nanovesicles that secreted by cells under physiological and pathological conditions. Cargo loaded into exosomes including protein, lipids and nucleic acids can be delivered to recipient cells. Therefore, exosomes are recognized as important mediators for intercellular communication. It has been suggested that exosomes from stem cells (eg. embryonic stem cells, induced pluripotent stem cells, cardiac progenitor cells, mesenchymal stem cells and cardiosphere-derived cells) have protective effects against heart injury. In this review, we summarized recent research progresses on stem cell-derived exosomes in myocardial injury, including the therapeutic effects and mechanism.

Exosomes as potential drug delivery tools for treatment of cardiovascular diseases / 中国药理学与毒理学杂志

Exosomes serve as vesicles to deliver protein, lipids, nucleic acids or other cellular components, to neighboring or distant cells. Recent studies have highlighted the potential therapeutic effects of stem cell-derived exosomes on cancer and cardiovascular diseases. Our previous studie-shave investigated the role of stem cell-derived exosomes in cardiac protection. Mesenchymalstem cells released miR-22-enriched exosomes after ischemic preconditioning and these exosomes showed protective effects oncardiomyocytes.MiR-21-conaining exosomes were secreted by H2O2-treated cardiac progenitor cells and protected cardiomyocytes from H2O2-induced apoptosis. Heat-shock lead to the production ofheat shock factor 1-enriched exosomes from cardiac stem cells, which reducedapoptosis of cardiomyocytes. Given these important effects of exosomes in intercellular communications, exosomes have been proposed as a vector for drug delivery or other therapeutic purposes. However, cells secretea limited number of exosomes, which has hampered the development of exosomes for research and clinical application.Synthetic exosome-mimics by cellextrusion or cell membrane-cloaked nanoparticles, which canbe fabricated on a large-scale, provide novel platforms fordrug delivery. Two Korean groups fabricated exosome-mimetic nanovesicles by extruding monocytes or macrophages through a serial of filters and utilized these exosome-mimetics for the delivery of anti-tumor drug. Recently,cell membrane-cloaked nanoparticles have emergedas a potential tool for drug delivery with the advantages ofimmunocompatibility, stability and targeting capabilityfor the treatment of cancer. In summary, exosomes or exosome-mimics may serve as potential therapeutic tools for the treatment of cardiovascular diseases.