BACKGROUND： Recently, many investigators have tried to use natural biomaterials, such as, artery, vein, decalcified bone, etc., as conduits for nerve repair. However, immunological rejection of conduits made of natur...BACKGROUND： Recently, many investigators have tried to use natural biomaterials, such as, artery, vein, decalcified bone, etc., as conduits for nerve repair. However, immunological rejection of conduits made of natural biomaterials limits their application. Therefore, it is essential to identify more suitable types of biomaterials. OBJECTIVE： To observe the characteristics of a bioengineering processing method using venous conduit as a stent for repairing facial nerve injury. DESIGN： A controlled observational experiment. SETTING： Animal Laboratories of the Third Hospital Affiliated to Sun Yat-sen University and the 157 Hospital. MATERIALS： Thirty-three male New Zealand rabbits of pure breed, weighing 1.5 to 2.0 kg, were provided by Medical Experimental Animal Room of Sun Yat-sen University. The protocol was carried out in accordance with animal ethics guidelines for the use and care of animals. Venous conduits and autogenous nerves were transplanted into the left and right cheeks, respectively. Eleven animals were chosen for anatomical observations at 5, 10 and 15 weeks after surgery. METHODS： This experiment was carried out in the Animal Laboratories of the Third Hospital Affdiated to Sun Yat-sen University and the 157 Hospital between May and November 2006. After animals were anesthetized, 15 mm of retromandibular vein was harvested for preparing a venous conduit. Approximately 3 cm of low buccal branch of facial nerve was exposed. A segment of 1.2 cm nerve was resected from the middle, and a gap of 1.5 cm formed due to bilateral retraction. The prepared venous conduit of 1.5 cm was sutured to the outer membrane of the severed ends of the nerve. Muscle and skin were sutured layer by layer. Using the same above-mentioned method, the low buccal branch of right autogenous facial nerve was resected, and the left facial nerve segment from the same animal was transplanted using end-to-end neurorrhaphy for control. MAIN OUTCOME MEASURES： （1）Post-operatively, food intake, vibrissae activity and wound healing of each animal were observed daily. （2） Animals were anesthetized at 5, 10 and 15 weeks after operation for observing the structural change of the venous conduit, the appearance of regenerated nerve, and the relationship between conduit and peripheral muscle tissue. （3） The action potential and latency of bilateral nerves of animals were measured by electrophysiologic examination, and nerve conduction velocity was calculated. （4）Neural myelination and neurite growth were observed by histological staining using an optical microscope. RESULTS： Thirty-three New Zealand rabbits were involved in the final analysis. （1）Immediately following the operation, vibrissae activity and orbicularis otis muscle activity of the upper lip on venous conduit side were more prominent, and their amplitudes of movement were larger as compared with autogenous nerve side. （2） At postoperative 10 weeks, by visual inspection, we found that on the venous conduit side, the venous conduit exhibited membrane structure which encased regenerated nerve. Regenerated nerve adhered to the muscle edge of orbicularis oris muscle. Muscle and nerve could be separated with a forceps. The muscle of musculus orbicularis oris of rabbit was darker and thicker as compared with autogenous nerve side. After the venous conduit was longitudinally split, the regenerated nerve and nerves at two the severed ends were connected together. When compared with postoperative 5 weeks, the connected nerve was thickened, texture was tough and its middle part was thicker than its two ends. On the autogenous nerve side, the regenerated nerve stem was enwrapped by scar tissue. It was bulky and adhered to peripheral muscle. Its neural profile structure was unclear. The two stomas were obviously enlarged. （3）At postoperative 10 weeks and 15 weeks, nerve action potentials could be elicited from both the venous conduit and autologous nerve side. The mean nerve conduction velocity on the venous conduit side was greater than that of the autologous nerve side. （4）At postoperative 10 weeks, using histochemical staining, it was found that in the venous conduit, regenerated medullated nerve fibers were densely distributed, with well split facial nerve structure, while on the autologous nerve side, nerve fibers were sparsely scattered, with immature medullated nerve structure. CONCLUSION： Biological natural venous conduit processed by bioengineering technology overcomes the tissue inflammatory reactions and connective tissue reactions caused by natural biomaterials. It is more conducive to promote neural regeneration and functional recovery than autologous nerve transplantation.展开更多
BACKGROUND：In previous studies of skull defects and regeneration, bone morphogenetic protein as an inductor and nanohydroxyapatite as a scaffold have been cocultured with osteoblasts. OBJECTIVE： To verify the charac...BACKGROUND：In previous studies of skull defects and regeneration, bone morphogenetic protein as an inductor and nanohydroxyapatite as a scaffold have been cocultured with osteoblasts. OBJECTIVE： To verify the characteristics of the new skull regenerated material after compound soft regenerated skull material implantation. DESIGN, TIME AND SETTING： The self-control and inter-group control animal experiment was performed at the Sun Yat-sen University, China from February to July 2007. MATERIALS： Twenty-four healthy adult dogs of both genders weighing 15–20 kg were used in this study. Nanohydroxyapatite as a scaffold was cocultured with osteoblasts. Using demineralized canine bone matrix as a carrier, recombinant human bone morphogenetic protein-2 was employed to prepare compound soft regenerated skull material. Self-designed compound soft regenerated skull material was implanted in models of skull defects. METHODS： Animals were randomly assigned into two groups, Group A （n = 16） and Group B （n = 8）. Bilateral 2.5-cm-diameter full-thickness parietal skull defects were made in all animals. In Group A, the right side was reconstructed with calcium alginate gel, osteoblasts, and nanometer bone meal composite; the left side was reconstructed with calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 composite. In Group B, the right side was kept as a simple skull defect, and the left side was reconstructed with calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 composite. MAIN OUTCOME MEASURES： Bone regeneration and histopathological changes at the site of the skull defect were observed with an optical microscope and a scanning electron microscope after surgery. The ability to form bone was measured by alizarin red S staining. In vitro cultured osteoblasts were observed for morphology. RESULTS： One month following surgery, newly formed bone trabeculae mostly covered the broken ends of the fractured bone and grew towards the defect regions. Two months after surgery, many disordered bone islands had formed. Three months after surgery, mature bone, medullary cavities and a large number of new bones were detected in the defect regions. Six months after surgery, the left defect was mostly repaired, with a high bone density compared with the right side in Groups A and B. The right defect was mostly repaired in Group A, but only a small fraction of the right defects was repaired in Group B. CONCLUSION： A composite of calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 can metabolize by itself, gradually ossify and form new bone.展开更多
The hydrolysis product of dextranase contains highly polymerized oligomeric isomaltose,which can be used as prebiotics to promote the colonization of probiotics,thus adjusting the ecological environment of intestinal ...The hydrolysis product of dextranase contains highly polymerized oligomeric isomaltose,which can be used as prebiotics to promote the colonization of probiotics,thus adjusting the ecological environment of intestinal flora.In this study,the expression of dextranase(PsDex1711)in Bacillus subtilis WB600 was enhanced by screening signal peptides.Furthermore,the potential application of dextranase for functional starch preparation was explored.Initially,a signal peptide library was constructed to identify the most efficient signal peptide for PsDex1711 secretion.Then,enzymatic hydrolysis was employed to produce porous buckwheat starch with varying pore sizes,and the impact of this enzymatic treatment on the physicochemical and microstructural properties of buckwheat starch was investigated.Signal peptide of the YwoF protein of unknown function demonstrated the highest extracellular PsDex1711 activity at 2.10±0.036 U/mL.Moreover,scanning electron microscope analysis revealed the development of deeper pores on the surface of starch granules after 18 h of enzymatic treatment,indicating the microstructural alterations induced by the enzymatic process and providing a foundation for further research in this field.The enzymatic hydrolysis also resulted in 40%and 35%increase in the water and oil absorption,respectively,compared to natural starch.Based on x-ray diffraction and Fourier transform infrared spectroscopy,it was inferred that the porous starch had a high degree of short-range ordering,which could provide a theoretical basis for the development and application of porous starch materials.展开更多
Carrier migration path and driving forces are two crucial factors for charge separation of heterojunction with efficient photoelectric response from the thermodynamic and kinetic perspectives,respectively.Constructing...Carrier migration path and driving forces are two crucial factors for charge separation of heterojunction with efficient photoelectric response from the thermodynamic and kinetic perspectives,respectively.Constructing the S-scheme heterojunction and achieving an efficient migration path for space charge separation have aroused great interest,while a thorough insight into tuning interfacial band bending for S-scheme heterojunction is absent.Herein,we report a class of Zn atom-doped CeO_(2)/g-C_(3)N_(4) heterostructure for achieving a new carrier migration path conversion from inferior type-II to advanced S-scheme.Zn-dependent volcano-type plot for Zn-CeO_(2) is established to tune the Fermi level of CeO_(2).The built-in electric field for carrier flow dynamics strengthens when coupling with g-C_(3)N_(4),which significantly boosts the photoelectric response.Based on the intrinsic enzymelike activity of Zn-CeO_(2),we further demonstrate that the Zn-CeO_(2)/g-C_(3)N_(4) S-scheme heterojunction can be explored for constructing a sensitive nanozymatic photoelectrochemical biosensor for the detection of acetylcholinesterase.展开更多
基金Science and Technology Bureau of Guangdong Province, No.2004B33801007Scienceand Technology Bureau of Guangzhou City, No.2007Z3-D2031
文摘BACKGROUND： Recently, many investigators have tried to use natural biomaterials, such as, artery, vein, decalcified bone, etc., as conduits for nerve repair. However, immunological rejection of conduits made of natural biomaterials limits their application. Therefore, it is essential to identify more suitable types of biomaterials. OBJECTIVE： To observe the characteristics of a bioengineering processing method using venous conduit as a stent for repairing facial nerve injury. DESIGN： A controlled observational experiment. SETTING： Animal Laboratories of the Third Hospital Affiliated to Sun Yat-sen University and the 157 Hospital. MATERIALS： Thirty-three male New Zealand rabbits of pure breed, weighing 1.5 to 2.0 kg, were provided by Medical Experimental Animal Room of Sun Yat-sen University. The protocol was carried out in accordance with animal ethics guidelines for the use and care of animals. Venous conduits and autogenous nerves were transplanted into the left and right cheeks, respectively. Eleven animals were chosen for anatomical observations at 5, 10 and 15 weeks after surgery. METHODS： This experiment was carried out in the Animal Laboratories of the Third Hospital Affdiated to Sun Yat-sen University and the 157 Hospital between May and November 2006. After animals were anesthetized, 15 mm of retromandibular vein was harvested for preparing a venous conduit. Approximately 3 cm of low buccal branch of facial nerve was exposed. A segment of 1.2 cm nerve was resected from the middle, and a gap of 1.5 cm formed due to bilateral retraction. The prepared venous conduit of 1.5 cm was sutured to the outer membrane of the severed ends of the nerve. Muscle and skin were sutured layer by layer. Using the same above-mentioned method, the low buccal branch of right autogenous facial nerve was resected, and the left facial nerve segment from the same animal was transplanted using end-to-end neurorrhaphy for control. MAIN OUTCOME MEASURES： （1）Post-operatively, food intake, vibrissae activity and wound healing of each animal were observed daily. （2） Animals were anesthetized at 5, 10 and 15 weeks after operation for observing the structural change of the venous conduit, the appearance of regenerated nerve, and the relationship between conduit and peripheral muscle tissue. （3） The action potential and latency of bilateral nerves of animals were measured by electrophysiologic examination, and nerve conduction velocity was calculated. （4）Neural myelination and neurite growth were observed by histological staining using an optical microscope. RESULTS： Thirty-three New Zealand rabbits were involved in the final analysis. （1）Immediately following the operation, vibrissae activity and orbicularis otis muscle activity of the upper lip on venous conduit side were more prominent, and their amplitudes of movement were larger as compared with autogenous nerve side. （2） At postoperative 10 weeks, by visual inspection, we found that on the venous conduit side, the venous conduit exhibited membrane structure which encased regenerated nerve. Regenerated nerve adhered to the muscle edge of orbicularis oris muscle. Muscle and nerve could be separated with a forceps. The muscle of musculus orbicularis oris of rabbit was darker and thicker as compared with autogenous nerve side. After the venous conduit was longitudinally split, the regenerated nerve and nerves at two the severed ends were connected together. When compared with postoperative 5 weeks, the connected nerve was thickened, texture was tough and its middle part was thicker than its two ends. On the autogenous nerve side, the regenerated nerve stem was enwrapped by scar tissue. It was bulky and adhered to peripheral muscle. Its neural profile structure was unclear. The two stomas were obviously enlarged. （3）At postoperative 10 weeks and 15 weeks, nerve action potentials could be elicited from both the venous conduit and autologous nerve side. The mean nerve conduction velocity on the venous conduit side was greater than that of the autologous nerve side. （4）At postoperative 10 weeks, using histochemical staining, it was found that in the venous conduit, regenerated medullated nerve fibers were densely distributed, with well split facial nerve structure, while on the autologous nerve side, nerve fibers were sparsely scattered, with immature medullated nerve structure. CONCLUSION： Biological natural venous conduit processed by bioengineering technology overcomes the tissue inflammatory reactions and connective tissue reactions caused by natural biomaterials. It is more conducive to promote neural regeneration and functional recovery than autologous nerve transplantation.
基金the Science and Technology Foundation of Technology Department of Guangdong Province, No. 2007B031003001the Science Research Foundation of Technology Bureau of Guangzhou City, No. 2006CBG0091
文摘BACKGROUND：In previous studies of skull defects and regeneration, bone morphogenetic protein as an inductor and nanohydroxyapatite as a scaffold have been cocultured with osteoblasts. OBJECTIVE： To verify the characteristics of the new skull regenerated material after compound soft regenerated skull material implantation. DESIGN, TIME AND SETTING： The self-control and inter-group control animal experiment was performed at the Sun Yat-sen University, China from February to July 2007. MATERIALS： Twenty-four healthy adult dogs of both genders weighing 15–20 kg were used in this study. Nanohydroxyapatite as a scaffold was cocultured with osteoblasts. Using demineralized canine bone matrix as a carrier, recombinant human bone morphogenetic protein-2 was employed to prepare compound soft regenerated skull material. Self-designed compound soft regenerated skull material was implanted in models of skull defects. METHODS： Animals were randomly assigned into two groups, Group A （n = 16） and Group B （n = 8）. Bilateral 2.5-cm-diameter full-thickness parietal skull defects were made in all animals. In Group A, the right side was reconstructed with calcium alginate gel, osteoblasts, and nanometer bone meal composite; the left side was reconstructed with calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 composite. In Group B, the right side was kept as a simple skull defect, and the left side was reconstructed with calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 composite. MAIN OUTCOME MEASURES： Bone regeneration and histopathological changes at the site of the skull defect were observed with an optical microscope and a scanning electron microscope after surgery. The ability to form bone was measured by alizarin red S staining. In vitro cultured osteoblasts were observed for morphology. RESULTS： One month following surgery, newly formed bone trabeculae mostly covered the broken ends of the fractured bone and grew towards the defect regions. Two months after surgery, many disordered bone islands had formed. Three months after surgery, mature bone, medullary cavities and a large number of new bones were detected in the defect regions. Six months after surgery, the left defect was mostly repaired, with a high bone density compared with the right side in Groups A and B. The right defect was mostly repaired in Group A, but only a small fraction of the right defects was repaired in Group B. CONCLUSION： A composite of calcium alginate gel, osteoblasts, nanometer bone meal and recombinant human bone morphogenetic protein-2 can metabolize by itself, gradually ossify and form new bone.
基金supported by the National Natural Science Foundation of China(32172154)the National Key R&D Program of China(2022YFC2805101)The Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).Post-graduate Research&Practice Innovation Program of Jiangsu(IOU22-94).
文摘The hydrolysis product of dextranase contains highly polymerized oligomeric isomaltose,which can be used as prebiotics to promote the colonization of probiotics,thus adjusting the ecological environment of intestinal flora.In this study,the expression of dextranase(PsDex1711)in Bacillus subtilis WB600 was enhanced by screening signal peptides.Furthermore,the potential application of dextranase for functional starch preparation was explored.Initially,a signal peptide library was constructed to identify the most efficient signal peptide for PsDex1711 secretion.Then,enzymatic hydrolysis was employed to produce porous buckwheat starch with varying pore sizes,and the impact of this enzymatic treatment on the physicochemical and microstructural properties of buckwheat starch was investigated.Signal peptide of the YwoF protein of unknown function demonstrated the highest extracellular PsDex1711 activity at 2.10±0.036 U/mL.Moreover,scanning electron microscope analysis revealed the development of deeper pores on the surface of starch granules after 18 h of enzymatic treatment,indicating the microstructural alterations induced by the enzymatic process and providing a foundation for further research in this field.The enzymatic hydrolysis also resulted in 40%and 35%increase in the water and oil absorption,respectively,compared to natural starch.Based on x-ray diffraction and Fourier transform infrared spectroscopy,it was inferred that the porous starch had a high degree of short-range ordering,which could provide a theoretical basis for the development and application of porous starch materials.
基金supported by the National Natural Science Foundation of China(22104114)the Natural Science Foundation of Hubei Province(2021CFB518)+1 种基金the Fundamental Research Funds for the Central Universities(CCNU22JC006)the Program of Introducing Talents of Discipline to Universities of China(111 Program,B17019)。
文摘Carrier migration path and driving forces are two crucial factors for charge separation of heterojunction with efficient photoelectric response from the thermodynamic and kinetic perspectives,respectively.Constructing the S-scheme heterojunction and achieving an efficient migration path for space charge separation have aroused great interest,while a thorough insight into tuning interfacial band bending for S-scheme heterojunction is absent.Herein,we report a class of Zn atom-doped CeO_(2)/g-C_(3)N_(4) heterostructure for achieving a new carrier migration path conversion from inferior type-II to advanced S-scheme.Zn-dependent volcano-type plot for Zn-CeO_(2) is established to tune the Fermi level of CeO_(2).The built-in electric field for carrier flow dynamics strengthens when coupling with g-C_(3)N_(4),which significantly boosts the photoelectric response.Based on the intrinsic enzymelike activity of Zn-CeO_(2),we further demonstrate that the Zn-CeO_(2)/g-C_(3)N_(4) S-scheme heterojunction can be explored for constructing a sensitive nanozymatic photoelectrochemical biosensor for the detection of acetylcholinesterase.
