Complex craniofacial surgeries of damaged tissues have several limitations,which present complications and challenges when trying to replicate facial function and structure.Traditional treatment techniques have shown ...Complex craniofacial surgeries of damaged tissues have several limitations,which present complications and challenges when trying to replicate facial function and structure.Traditional treatment techniques have shown suitable nerve function regeneration with various drawbacks.As technology continues to advance,new methods have been explored in order to regenerate damaged nerves in an effort to more efficiently and effectively regain original function and structure.This article will summarize recent bioengineering strategies involving biodegradable composite scaffolds,bioactive factors,and external stimuli alone or in combination to support peripheral nerve regeneration.Particular emphasis is made on the contributions of growth factors and electrical stimulation on the regenerative process.展开更多
Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed...Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed repair of peripheral nerve tissue. In this study, a rat model of sciatic nerve transec- tion injury was repaired with a biodegradable conduit at 1 day, 1 week, 1 month and 2 months after injury, when the rats were divided into two subgroups. In the experimental group, rats were treated with electrical stimuli of frequency of 20 Hz, pulse width 100 ms and direct current voltage of 3 V; while rats in the control group received no electrical stimulation after the conduit operation. His- tological results showed that stained collagen fibers comprised less than 20% of the total operated area in the two groups after delayed repair at both 1 day and 1 week but after longer delays, the collagen fiber area increased with the time after injury. Immunohistochemical staining revealed that the expression level of transforming growth factor ~ （an indicator of tissue fibrosis） decreased at both 1 day and 1 week after delayed repair but increased at both 1 and 2 months after delayed repair. These findings indicate that if the biodegradable conduit repair combined with electrical stimulation is delayed, it results in a poor outcome following sciatic nerve injury. One month after injury, tissue degeneration and distal fibrosis are apparent and are probably the main reason why electrical stimulation fails to promote nerve regeneration after delayed repair.展开更多
Poypyrrole(PPy)films were prepared at 1×10 -3 mA/cm 2 electropolymerization current density on indium tin oxide(ITO)substrate.The PPy films were well distributed,translucent,stable and insoluble.Moreover,they can...Poypyrrole(PPy)films were prepared at 1×10 -3 mA/cm 2 electropolymerization current density on indium tin oxide(ITO)substrate.The PPy films were well distributed,translucent,stable and insoluble.Moreover,they can be steri lized by steam disinfection.Rat hepatic cells were cultured on these films.The results show that PPy films have good biocompatibility and they can accelerate cell growth under electrical stimulation.The cells on PPy films reach the largest cell density earlier than the cells on tissue culture polystyrene(TCPS).Furthermore,rat hepatic cells can generate on PPy films.The cells on PPy films grow faster and enter logarithmic growth phase earlier than those on TCPS.展开更多
The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of sate...The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of satellite bacteria isolated from nonaxenic SSP cultures,and Escherichia coli were screened.Results indicate that ethanol could promote the growth and photo synthetic efficiency(F_(v)/F_(m))of S SP at 0.01%and the growth of satellite bacteria at 0.01%-1%.Nevertheless,ethanol inhibited the growth and F_(v)/F_(m)of SSP at 0.1%-1%,and killed bacteria and SSP at 10% concentration.Further investigation on a satellite bacterium(Mameliella alba)revealed that ethanol promotes growth by serving as a growth stimulant rather than a metabolic carbon source.The 16 S rRNA gene amplicon indicated that all nonaxenic S SP cultures harbor distinct satellite bacteria communities where the SSP culture of Skeletonema costatum,Phaeodactylum tricornutum,and Dunaliella bardawil were dominated by bacteria genera of Marivita(~80%),Dinoroseobacter(~47%),and Halomonas(~87%),respectively,indicating that every SSP cultures have their own distinct satellite bacterial community.The bacteria family Rhodobacteraceae was dominant in the two marine diatoms,whereas Halomonadaceae was dominant in the saline green microalga.Compared to their respective controls,the supply of 0.5% ethanol to SSP cultures promoted the growth of the satellite bacteria but did not cause a significant difference in species composition of satellite bacteria.Therefore,a low concentration of ethanol can promote the growth of bacteria in a non-selective way.This study enriched our knowledge about the effect of ethanol on aquatic microbes and provided a baseline for basic and applied biotechnological re search in the aquatic environment in the future.展开更多
Objective:To investigate the role of vascular endothelial growth factor(VEGF)165a,VEGF165b,and VEGF receptor(VEGFR)in the development of bovine follicles.Methods:We cultured follicular cells that were collected from s...Objective:To investigate the role of vascular endothelial growth factor(VEGF)165a,VEGF165b,and VEGF receptor(VEGFR)in the development of bovine follicles.Methods:We cultured follicular cells that were collected from small,medium,and large sized bovine follicles with estrogen and measured the expression of VEGF,VEGFR2 and VEGF165b by Western blot analysis and immunofluorescence.Results:The expression of VEGF165 increased in all follicle sizes and the expression of VEGF165b was increased in the small and large follicles after culturing in an estrogen containing medium.The expression of VEGFR2 was increased in the medium and large follicles after culturing with estrogen for 96 h.VEGF165 was activated at 100 ng/mL estrogen in the large follicles for 96 h.In addition,VEGFR2 was upregulated in the medium and large follicles after treated with 100 ng/mL estrogen for 96 h.Conclusions:This evidence suggests that the expression of VEGF165 and VEGFR is associated with estrogen stimulation during the development of bovine follicles and in an autocrine or paracrine manner.This reveals an advantage during oocyte maturation in vitro.展开更多
Increasing stress from global warming, sea level rise, acidification, sedimentation, pollution, and unsustainable practices have degraded the most critical coastal ecosystems including coral reefs, oyster reefs, and s...Increasing stress from global warming, sea level rise, acidification, sedimentation, pollution, and unsustainable practices have degraded the most critical coastal ecosystems including coral reefs, oyster reefs, and salt marshes. Conventional restoration methods work only under perfect conditions, but fail nearly completely when the water becomes too hot or water quality deteriorates. New methods are needed to greatly increase settlement, growth, survival, and resistance to environmental stress of keystone marine organisms in order to maintain critical coastal ecosystem functions including shore protection, fisheries, and biodiversity. Electrolysis methods have been applied to marine ecosystem restoration since 1976, with spectacular results (Figures 1(a)-(c)). This paper provides the first overall review of the data. Low-voltage direct current trickle charges are found to increase the settlement of corals 25.86 times higher than uncharged control sites, to increase the mean growth rates of reef-building corals, soft corals, oysters, and salt marsh grass— an average of 3.17 times faster than controls (ranging from 2 to 10 times depending on species and conditions), and to increase the survival of electrically charged marine organisms—an average of 3.47 times greater than controls, with the biggest increases under the most severe environmental stresses. These results are caused by the fundamental biophysical stimulation of natural biochemical energy production pathways, used by all organisms, provided by electrical stimulation under the right conditions. This paper reviews for the first time all published results from properly designed, installed, and maintained projects, and contrasts them with those that do not meet these criteria.展开更多
Fibroblast growth factor （FGF） receptor substrate 2a （FRS2α） is the main mediator of signaling in the FGF pathway. Recent studies have shown that mitogen-activated protein kinase （MAPK） phosphorylates serine an...Fibroblast growth factor （FGF） receptor substrate 2a （FRS2α） is the main mediator of signaling in the FGF pathway. Recent studies have shown that mitogen-activated protein kinase （MAPK） phosphorylates serine and threonine residues in FRS2, negatively affecting FGF-induced tyrosine phosphorylation （PY） of FRS2. Several kinds of stimuli can induce serine/threonine phosphorylation （PS/T） of FRS2, indicating that FRS2 may be useful for studying crosstalk between growth factor signaling pathways. Here, we report that FGF-induced PY of FRS2 can be attenuated by EGF co-stimulation in PC12cells; this inhibitory effect could be completely reversed by U0126, an inhibitor of MEK. We further identified the ERK1/2-binding motif in FRS2 and generated FRS2-3KL, a mutant lacking MAPK binding and PT upon FGF and/or EGF stimulation. Unlike wild-type （WT） FRS2, FGF-induced PY of FRS2-3KL could not be inhibited by EGF co-stimulation, and FRS2-3KL-expressing PC12 cells exhibited more differentiating potential than FRS2-WT-expressing cells in response to FGF treatment. These results suggest that PS/T of FRS2 mediated by the FRS2-MAPK negative regulatory loop may function as a molecular switch integrating negative regulatory signals from other pathways into FGFR-generated signal transduction.展开更多
Peripheral nerve injuries are relatively common and can be caused by a variety of traumatic events such as motor vehicle accidents.They can lead to long-term disability,pain,and financial burden,and contribute to poor...Peripheral nerve injuries are relatively common and can be caused by a variety of traumatic events such as motor vehicle accidents.They can lead to long-term disability,pain,and financial burden,and contribute to poor quality of life.In this review,we systematically analyze the contemporary literature on peripheral nerve gap management using nerve prostheses in conjunction with physical therapeutic agents.The use of nerve prostheses to assist nerve regeneration across large gaps(> 30 mm) has revolutionized neural surgery.The materials used for nerve prostheses have been greatly refined,making them suitable for repairing large nerve gaps.However,research on peripheral nerve gap management using nerve prostheses reports inconsistent functional outcomes,especially when prostheses are integrated with physical therapeutic agents,and thus warrants careful investigation.This review explores the effectiveness of nerve prostheses for bridging large nerve gaps and then addresses their use in combination with physical therapeutic agents.展开更多
基金funding support from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health(R01EB020640)the Connecticut Regenerative Medicine Research Fund(15-RMBUCHC-08)the Department of Defense(OR120140).
文摘Complex craniofacial surgeries of damaged tissues have several limitations,which present complications and challenges when trying to replicate facial function and structure.Traditional treatment techniques have shown suitable nerve function regeneration with various drawbacks.As technology continues to advance,new methods have been explored in order to regenerate damaged nerves in an effort to more efficiently and effectively regain original function and structure.This article will summarize recent bioengineering strategies involving biodegradable composite scaffolds,bioactive factors,and external stimuli alone or in combination to support peripheral nerve regeneration.Particular emphasis is made on the contributions of growth factors and electrical stimulation on the regenerative process.
基金supported by grants from the National Program on Key Basic Research Project of China(973 Program),No.2014CB542206Program for Innovative Research Team in University of Ministry of Education of China,No.IRT1201+2 种基金the National Natural Science Foundation of China,No.31271284,31171150,81171146,30971526,31100860,31040043,31440055the Natural Science Foundation of Beijing of China,No.7142164Program for New Century Excellent Talents in University of Ministry of Education of China,No.BMU20110270
文摘Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed repair of peripheral nerve tissue. In this study, a rat model of sciatic nerve transec- tion injury was repaired with a biodegradable conduit at 1 day, 1 week, 1 month and 2 months after injury, when the rats were divided into two subgroups. In the experimental group, rats were treated with electrical stimuli of frequency of 20 Hz, pulse width 100 ms and direct current voltage of 3 V; while rats in the control group received no electrical stimulation after the conduit operation. His- tological results showed that stained collagen fibers comprised less than 20% of the total operated area in the two groups after delayed repair at both 1 day and 1 week but after longer delays, the collagen fiber area increased with the time after injury. Immunohistochemical staining revealed that the expression level of transforming growth factor ~ （an indicator of tissue fibrosis） decreased at both 1 day and 1 week after delayed repair but increased at both 1 and 2 months after delayed repair. These findings indicate that if the biodegradable conduit repair combined with electrical stimulation is delayed, it results in a poor outcome following sciatic nerve injury. One month after injury, tissue degeneration and distal fibrosis are apparent and are probably the main reason why electrical stimulation fails to promote nerve regeneration after delayed repair.
文摘Poypyrrole(PPy)films were prepared at 1×10 -3 mA/cm 2 electropolymerization current density on indium tin oxide(ITO)substrate.The PPy films were well distributed,translucent,stable and insoluble.Moreover,they can be steri lized by steam disinfection.Rat hepatic cells were cultured on these films.The results show that PPy films have good biocompatibility and they can accelerate cell growth under electrical stimulation.The cells on PPy films reach the largest cell density earlier than the cells on tissue culture polystyrene(TCPS).Furthermore,rat hepatic cells can generate on PPy films.The cells on PPy films grow faster and enter logarithmic growth phase earlier than those on TCPS.
基金Supported by the National Natural Science Foundation of China(Nos.42076114,41876146)the China Postdoctoral Science Foundation Grant(No.2018M632580)the Special Investigation Project of Scientific and Technological Fundamental Resources(No.2018FY100202)。
文摘The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of satellite bacteria isolated from nonaxenic SSP cultures,and Escherichia coli were screened.Results indicate that ethanol could promote the growth and photo synthetic efficiency(F_(v)/F_(m))of S SP at 0.01%and the growth of satellite bacteria at 0.01%-1%.Nevertheless,ethanol inhibited the growth and F_(v)/F_(m)of SSP at 0.1%-1%,and killed bacteria and SSP at 10% concentration.Further investigation on a satellite bacterium(Mameliella alba)revealed that ethanol promotes growth by serving as a growth stimulant rather than a metabolic carbon source.The 16 S rRNA gene amplicon indicated that all nonaxenic S SP cultures harbor distinct satellite bacteria communities where the SSP culture of Skeletonema costatum,Phaeodactylum tricornutum,and Dunaliella bardawil were dominated by bacteria genera of Marivita(~80%),Dinoroseobacter(~47%),and Halomonas(~87%),respectively,indicating that every SSP cultures have their own distinct satellite bacterial community.The bacteria family Rhodobacteraceae was dominant in the two marine diatoms,whereas Halomonadaceae was dominant in the saline green microalga.Compared to their respective controls,the supply of 0.5% ethanol to SSP cultures promoted the growth of the satellite bacteria but did not cause a significant difference in species composition of satellite bacteria.Therefore,a low concentration of ethanol can promote the growth of bacteria in a non-selective way.This study enriched our knowledge about the effect of ethanol on aquatic microbes and provided a baseline for basic and applied biotechnological re search in the aquatic environment in the future.
文摘Objective:To investigate the role of vascular endothelial growth factor(VEGF)165a,VEGF165b,and VEGF receptor(VEGFR)in the development of bovine follicles.Methods:We cultured follicular cells that were collected from small,medium,and large sized bovine follicles with estrogen and measured the expression of VEGF,VEGFR2 and VEGF165b by Western blot analysis and immunofluorescence.Results:The expression of VEGF165 increased in all follicle sizes and the expression of VEGF165b was increased in the small and large follicles after culturing in an estrogen containing medium.The expression of VEGFR2 was increased in the medium and large follicles after culturing with estrogen for 96 h.VEGF165 was activated at 100 ng/mL estrogen in the large follicles for 96 h.In addition,VEGFR2 was upregulated in the medium and large follicles after treated with 100 ng/mL estrogen for 96 h.Conclusions:This evidence suggests that the expression of VEGF165 and VEGFR is associated with estrogen stimulation during the development of bovine follicles and in an autocrine or paracrine manner.This reveals an advantage during oocyte maturation in vitro.
文摘Increasing stress from global warming, sea level rise, acidification, sedimentation, pollution, and unsustainable practices have degraded the most critical coastal ecosystems including coral reefs, oyster reefs, and salt marshes. Conventional restoration methods work only under perfect conditions, but fail nearly completely when the water becomes too hot or water quality deteriorates. New methods are needed to greatly increase settlement, growth, survival, and resistance to environmental stress of keystone marine organisms in order to maintain critical coastal ecosystem functions including shore protection, fisheries, and biodiversity. Electrolysis methods have been applied to marine ecosystem restoration since 1976, with spectacular results (Figures 1(a)-(c)). This paper provides the first overall review of the data. Low-voltage direct current trickle charges are found to increase the settlement of corals 25.86 times higher than uncharged control sites, to increase the mean growth rates of reef-building corals, soft corals, oysters, and salt marsh grass— an average of 3.17 times faster than controls (ranging from 2 to 10 times depending on species and conditions), and to increase the survival of electrically charged marine organisms—an average of 3.47 times greater than controls, with the biggest increases under the most severe environmental stresses. These results are caused by the fundamental biophysical stimulation of natural biochemical energy production pathways, used by all organisms, provided by electrical stimulation under the right conditions. This paper reviews for the first time all published results from properly designed, installed, and maintained projects, and contrasts them with those that do not meet these criteria.
文摘Fibroblast growth factor （FGF） receptor substrate 2a （FRS2α） is the main mediator of signaling in the FGF pathway. Recent studies have shown that mitogen-activated protein kinase （MAPK） phosphorylates serine and threonine residues in FRS2, negatively affecting FGF-induced tyrosine phosphorylation （PY） of FRS2. Several kinds of stimuli can induce serine/threonine phosphorylation （PS/T） of FRS2, indicating that FRS2 may be useful for studying crosstalk between growth factor signaling pathways. Here, we report that FGF-induced PY of FRS2 can be attenuated by EGF co-stimulation in PC12cells; this inhibitory effect could be completely reversed by U0126, an inhibitor of MEK. We further identified the ERK1/2-binding motif in FRS2 and generated FRS2-3KL, a mutant lacking MAPK binding and PT upon FGF and/or EGF stimulation. Unlike wild-type （WT） FRS2, FGF-induced PY of FRS2-3KL could not be inhibited by EGF co-stimulation, and FRS2-3KL-expressing PC12 cells exhibited more differentiating potential than FRS2-WT-expressing cells in response to FGF treatment. These results suggest that PS/T of FRS2 mediated by the FRS2-MAPK negative regulatory loop may function as a molecular switch integrating negative regulatory signals from other pathways into FGFR-generated signal transduction.
文摘Peripheral nerve injuries are relatively common and can be caused by a variety of traumatic events such as motor vehicle accidents.They can lead to long-term disability,pain,and financial burden,and contribute to poor quality of life.In this review,we systematically analyze the contemporary literature on peripheral nerve gap management using nerve prostheses in conjunction with physical therapeutic agents.The use of nerve prostheses to assist nerve regeneration across large gaps(> 30 mm) has revolutionized neural surgery.The materials used for nerve prostheses have been greatly refined,making them suitable for repairing large nerve gaps.However,research on peripheral nerve gap management using nerve prostheses reports inconsistent functional outcomes,especially when prostheses are integrated with physical therapeutic agents,and thus warrants careful investigation.This review explores the effectiveness of nerve prostheses for bridging large nerve gaps and then addresses their use in combination with physical therapeutic agents.
