Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alte...Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alternative to conventional therapies for the treatment of deep tumors. In our previous study, a large scale spherical HIFU-phased array was developed to ablate deep tumors. In the current study, taking into account the required focal depth and maximum acoustic power output, 90 identical circular PZT-8 elements （diameter=1.4 cm and frequency=l MHz） were mounted on a spherical shell with a radius of curvature of 18 cm and a diameter of 21 cm. With the developed array, computer simulations and ex vivo experiments were carried out. The simulation results theoretically demonstrate the ability of the array to focus and steer in the specified volume （a 2 cm×2 cm×3 cm volume） at the focal depth of 15 to 18 cm. Ex vivo experiment results also verify the capability of the developed array to ablate deep target tissue by either moving single focal point or generating multiple foci simultaneously.展开更多
In the past few years,there have been multiple advances in magnetic resonance (MR) instrumentation,in vivo devices,real-time imaging sequences and interventional procedures with new therapies.More recently,interventi... In the past few years,there have been multiple advances in magnetic resonance (MR) instrumentation,in vivo devices,real-time imaging sequences and interventional procedures with new therapies.More recently,interventionists have started to use minimally invasive image-guided procedures and local therapies,which reduce the pain from conventional surgery and increase drug effectiveness,respectively.Local therapy also reduces the systemic dose and eliminates the toxic side effects of some drugs to other organs.The success of MR-guided procedures depends on visualization of the targets in 3D and precise deployment of ablation catheters,local therapies and devices.MR contrast media provide a wealth of tissue contrast and allows 3D and 4D image acquisitions.After the development of fast imaging sequences,the clinical applications of MR contrast media have been substantially expanded to include pre-during-and post-interventions.Prior to intervention,MR contrast media have the potential to localize and delineate pathologic tissues of vital organs,such as the brain,heart,breast,kidney,prostate,liver and uterus.They also offer other options such as labeling therapeutic agents or cells.During intervention,these agents have the capability to map blood vessels and enhance the contrast between the endovascular guidewire/catheters/devices,blood and tissues as well as direct therapies to the target.Furthermore,labeling therapeutic agents or cells aids in visualizing their delivery sites and tracking their tissue distribution.After intervention,MR contrast media have been used for assessing the efficacy of ablation and therapies.It should be noted that most image-guided procedures are under preclinical research and development.It can be concluded that MR contrast media have great value in preclinical and some clinical interventional procedures.Future applications of MR contrast media in image-guided procedures depend on their safety,tolerability,tissue specificity and effectiveness in demonstrating success of the interventions an展开更多
We evaluate the ablation thresholds of Er：YAG and Er,Cr：YSGG laser for enamel and dentin. A total of 140 dental slices is evenly divided into two groups： the dentin group and the enamel group. Dental tissues are ir...We evaluate the ablation thresholds of Er：YAG and Er,Cr：YSGG laser for enamel and dentin. A total of 140 dental slices is evenly divided into two groups： the dentin group and the enamel group. Dental tissues are irradiated with either an Er：YAG laser or an Er, Cr：YSGG laser with pulse widths in the order of 100 μs. The laser fluence is increased gradually until the ablation crater is formed. The laser ablation threshold is calculated using probit analysis. The ablation thresholds of the Er：YAG laser for dentin and enamel range from 2.88 to 3.36 J/cm^2 and from 2.94 to 3.8 J/cm^2, respectively, and the ablation thresholds of the Er,Cr：YSGG laser for dentin and enamel range from 2.92 to 4.2 J/cm^2 and from 4.93 to 5.66 J/cm^2, respectivelv.展开更多
Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types...Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults （such as scar ablation） within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.展开更多
目的探讨心外膜脂肪组织（EAT）体积与心房颤动（AF）患者首次接受射频消融术后空白期复发的相关性。方法回顾性分析2014年1月至2016年5月收治的AF患者85例（AF组）及非AF患者90例（非AF组）的临床资料，均以螺旋CT检查对EAT体积进行测...目的探讨心外膜脂肪组织（EAT）体积与心房颤动（AF）患者首次接受射频消融术后空白期复发的相关性。方法回顾性分析2014年1月至2016年5月收治的AF患者85例（AF组）及非AF患者90例（非AF组）的临床资料，均以螺旋CT检查对EAT体积进行测量；术后随访6～18个月，以AF组术后空白期是否复发分为空白期AF复发组（观察组，27例）与空白期无AF复发组（对照组，58例），对比EAT体积在各组中的差异并进行相关性分析。结果观察组患者的总EAT体积[（118．71±28．94）cm^3 vs （97．73±24．86）cm^3]、左心房周EAT体积[（29．98±8．09）cm^3 vs（23．11±8．30）cm^3]显著高于对照组，差异有统计学意义（t=6．219、4．451，P〈0．01）。经多元Logistic回归分析提示，总EAT体积、左心房周EAT体积是独立预测AF发病的相关因素，也是独立预测射频}肖融术后空白期AF复发的因素；同时观察组患者的远期复发率[40．7％（11／27）]较对照组[15．5％（9／58）]更高，差异有统计学意义（X^2=7．142，P〈0．05）。结论当患者总EAT体积、左心房周EAT体积较大时，除了AF的发病率升高，首次接受射频消融术后空白期也更容易AF复发。展开更多
Alginate is a widely used hydrogel in tissue engineering owing to its simple and non-cytotoxic gelation process, ease of use, and abundance. However, unlike hydrogels derived from mammalian sources such as collagen, a...Alginate is a widely used hydrogel in tissue engineering owing to its simple and non-cytotoxic gelation process, ease of use, and abundance. However, unlike hydrogels derived from mammalian sources such as collagen, alginate does not contain cell adhesion Iigands. Here, we present a novel laser ablation technique for the in situ embedding of gold and iron nanoparticles into hydrogels. We hypothesized that integration of metal nanoparticles in alginate could serve as an alternative material because of its chemical biofunctionalization ability （coupling of RGD ligands） to favor cell adhesion. Cytocompatibility and biofunctionality of the gels were assessed by cell culture experiments using fibroblasts and endothelial cells. Nanoparticles with an average particle size of 3 nm （gold） and 6 nm （iron） were generated and stably maintained in alginate for up to 6 months. Using an extrusion system, several centimeter-long alginate tubes with an outer diameter of approximately 3 mm and a wall thickness of approximately 150 μm were manufactured. Confocal microscopy revealed homogeneously distributed nanoparticle agglomerates over the entire tube volume. Endothelial cells seeded on iron-loaded gels showed significantly higher viability and an increased degree of spreading, and the number of attached cells was also elevated in comparison to the control and gold-loaded alginates. We conclude that laser-based in situ integration of iron nanoparticles （40.01 wt.%） in alginate is a straightforward method to generate composite materials that favor the adhesion of endothelial cells. In addition, we show that nanoparticle integration does not impair the alginate＇s gelation and 3D biofabrication properties.展开更多
基金supported by the National Natural Science Foundation of China (No. 30800246)Shanghai Key Technologies R&D Programof China (No. 09441900500)
文摘Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alternative to conventional therapies for the treatment of deep tumors. In our previous study, a large scale spherical HIFU-phased array was developed to ablate deep tumors. In the current study, taking into account the required focal depth and maximum acoustic power output, 90 identical circular PZT-8 elements （diameter=1.4 cm and frequency=l MHz） were mounted on a spherical shell with a radius of curvature of 18 cm and a diameter of 21 cm. With the developed array, computer simulations and ex vivo experiments were carried out. The simulation results theoretically demonstrate the ability of the array to focus and steer in the specified volume （a 2 cm×2 cm×3 cm volume） at the focal depth of 15 to 18 cm. Ex vivo experiment results also verify the capability of the developed array to ablate deep target tissue by either moving single focal point or generating multiple foci simultaneously.
文摘 In the past few years,there have been multiple advances in magnetic resonance (MR) instrumentation,in vivo devices,real-time imaging sequences and interventional procedures with new therapies.More recently,interventionists have started to use minimally invasive image-guided procedures and local therapies,which reduce the pain from conventional surgery and increase drug effectiveness,respectively.Local therapy also reduces the systemic dose and eliminates the toxic side effects of some drugs to other organs.The success of MR-guided procedures depends on visualization of the targets in 3D and precise deployment of ablation catheters,local therapies and devices.MR contrast media provide a wealth of tissue contrast and allows 3D and 4D image acquisitions.After the development of fast imaging sequences,the clinical applications of MR contrast media have been substantially expanded to include pre-during-and post-interventions.Prior to intervention,MR contrast media have the potential to localize and delineate pathologic tissues of vital organs,such as the brain,heart,breast,kidney,prostate,liver and uterus.They also offer other options such as labeling therapeutic agents or cells.During intervention,these agents have the capability to map blood vessels and enhance the contrast between the endovascular guidewire/catheters/devices,blood and tissues as well as direct therapies to the target.Furthermore,labeling therapeutic agents or cells aids in visualizing their delivery sites and tracking their tissue distribution.After intervention,MR contrast media have been used for assessing the efficacy of ablation and therapies.It should be noted that most image-guided procedures are under preclinical research and development.It can be concluded that MR contrast media have great value in preclinical and some clinical interventional procedures.Future applications of MR contrast media in image-guided procedures depend on their safety,tolerability,tissue specificity and effectiveness in demonstrating success of the interventions an
基金supported by the National Natural Science Foundation of China(No.60878062)the Science Research Foundation of Ministry of Health & United Fujian Provincial Health and Education Project for Tackling the Key Research(No.WKJ2008-2-035)the Natural Science Foundation of Fujian Province(No.2012J01255)
文摘We evaluate the ablation thresholds of Er：YAG and Er,Cr：YSGG laser for enamel and dentin. A total of 140 dental slices is evenly divided into two groups： the dentin group and the enamel group. Dental tissues are irradiated with either an Er：YAG laser or an Er, Cr：YSGG laser with pulse widths in the order of 100 μs. The laser fluence is increased gradually until the ablation crater is formed. The laser ablation threshold is calculated using probit analysis. The ablation thresholds of the Er：YAG laser for dentin and enamel range from 2.88 to 3.36 J/cm^2 and from 2.94 to 3.8 J/cm^2, respectively, and the ablation thresholds of the Er,Cr：YSGG laser for dentin and enamel range from 2.92 to 4.2 J/cm^2 and from 4.93 to 5.66 J/cm^2, respectivelv.
文摘Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults （such as scar ablation） within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.
文摘目的探讨心外膜脂肪组织（EAT）体积与心房颤动（AF）患者首次接受射频消融术后空白期复发的相关性。方法回顾性分析2014年1月至2016年5月收治的AF患者85例（AF组）及非AF患者90例（非AF组）的临床资料，均以螺旋CT检查对EAT体积进行测量；术后随访6～18个月，以AF组术后空白期是否复发分为空白期AF复发组（观察组，27例）与空白期无AF复发组（对照组，58例），对比EAT体积在各组中的差异并进行相关性分析。结果观察组患者的总EAT体积[（118．71±28．94）cm^3 vs （97．73±24．86）cm^3]、左心房周EAT体积[（29．98±8．09）cm^3 vs（23．11±8．30）cm^3]显著高于对照组，差异有统计学意义（t=6．219、4．451，P〈0．01）。经多元Logistic回归分析提示，总EAT体积、左心房周EAT体积是独立预测AF发病的相关因素，也是独立预测射频}肖融术后空白期AF复发的因素；同时观察组患者的远期复发率[40．7％（11／27）]较对照组[15．5％（9／58）]更高，差异有统计学意义（X^2=7．142，P〈0．05）。结论当患者总EAT体积、左心房周EAT体积较大时，除了AF的发病率升高，首次接受射频消融术后空白期也更容易AF复发。
文摘Alginate is a widely used hydrogel in tissue engineering owing to its simple and non-cytotoxic gelation process, ease of use, and abundance. However, unlike hydrogels derived from mammalian sources such as collagen, alginate does not contain cell adhesion Iigands. Here, we present a novel laser ablation technique for the in situ embedding of gold and iron nanoparticles into hydrogels. We hypothesized that integration of metal nanoparticles in alginate could serve as an alternative material because of its chemical biofunctionalization ability （coupling of RGD ligands） to favor cell adhesion. Cytocompatibility and biofunctionality of the gels were assessed by cell culture experiments using fibroblasts and endothelial cells. Nanoparticles with an average particle size of 3 nm （gold） and 6 nm （iron） were generated and stably maintained in alginate for up to 6 months. Using an extrusion system, several centimeter-long alginate tubes with an outer diameter of approximately 3 mm and a wall thickness of approximately 150 μm were manufactured. Confocal microscopy revealed homogeneously distributed nanoparticle agglomerates over the entire tube volume. Endothelial cells seeded on iron-loaded gels showed significantly higher viability and an increased degree of spreading, and the number of attached cells was also elevated in comparison to the control and gold-loaded alginates. We conclude that laser-based in situ integration of iron nanoparticles （40.01 wt.%） in alginate is a straightforward method to generate composite materials that favor the adhesion of endothelial cells. In addition, we show that nanoparticle integration does not impair the alginate＇s gelation and 3D biofabrication properties.
