Hypertrichosis is one of the most common side effects of systemic cyclosporine A therapy.It has been previously shown that cyclosporine A induces anagen and inhibits catagen development in mice.In the present study,to...Hypertrichosis is one of the most common side effects of systemic cyclosporine A therapy.It has been previously shown that cyclosporine A induces anagen and inhibits catagen development in mice.In the present study,to explore the mechanisms of cyclosporine A,we investigated the effects of cyclosporine A on hair shaft elongation,hair follicle cell proliferation,apoptosis,and mRNA expression of selected growth factors using an organ culture model of mouse vibrissae.In this model,cyclosporine A stimulated hair growth of normal mouse vibrissae follicles by inhibiting catagen-like development and promoting matrix cell proliferation.In addition,cyclosporine A caused an increase in the expression of vascular endothelial growth factor（VEGF）,hepatocyte growth factor（HGF）,and nerve growth factor（NGF）,and inhibited follistatin expression.Our findings provide an explanation for the clinically observed effects of cyclosporine A on hair growth.The mouse vibrissae organ culture offers an attractive model for identifying factors involved in the modulation of hair growth.展开更多
The Structure of mammalian vibrissa was observed microscopically and the relationship of morphologyand function was discussed. The vibrissa is conical. The elasticity and tenacity of vibrissa are stronger than that of...The Structure of mammalian vibrissa was observed microscopically and the relationship of morphologyand function was discussed. The vibrissa is conical. The elasticity and tenacity of vibrissa are stronger than that ofpelage hair. The scales are shaped irregular on vibrissa shaft except for the root part, because of tractional damages. This type of scales is of great importance in preventing the vibrissa from being totally destroyed. Cortex ofvibrissa is observed very well developed, thus its elasticity and tenacity work well in touching and sensing. Medullaof vibrissa is not well developed because vibrissa has been evaluated to fail in warm-keeping function.展开更多
A mathematical model of vibrissa motoneurons (vMN), which has been developed by Harish and Golomb, can show repetitive spiking in response to a transient external stimulation. The vMN model is described by a system of...A mathematical model of vibrissa motoneurons (vMN), which has been developed by Harish and Golomb, can show repetitive spiking in response to a transient external stimulation. The vMN model is described by a system of nonlinear ordinary differential equations based on the Hodgkin-Huxley scheme. The vMN model is regulated by various types of ionic conductances, such as persistent sodium, transient sodium, delayed-rectifier potassium, and slow ionic conductances (e.g., slowly activating potassium afterhyperpolarization (AHP) conductance and h conductance). In the present study, a numerical simulation analysis of the vMN model was performed to investigate the effect of variations in the transient sodium and the slow ionic conductance values on the response of the vMN model to a transient external stimulation. Numerical simulations revealed that when both the transient sodium and the AHP conductances are eliminated, the vMN model shows a bistable behavior (i.e., a stimulation-triggered transition between dynamic states). In contrast, none of the following induce the transition alone: 1) elimination of the transient sodium conductance;2) elimination of the AHP conductance;3) elimination of the h conductance;or 4) elimination of both the transient sodium and the h conductances.展开更多
The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)sin...The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)since 1980.One contributing factor to the decline may be exposure to anthropogenic contaminants such as persistent organic pollutants(POPs)which are biologically accumulative in nature,toxic to organisms,and environmentally persistent.This study conducted a decadal comparison of 21 organochlorine(OC)and 39 polybrominated diphenyl ether(PBDE)analyte concentrations utilizing archived vibrissae(whiskers)from individual fur seals sampled in 1993(n=30)and 2013(n=41)during subsistence harvests on the Pribilof Islands.The recently phased out PBDEs had values five times greater than the legacy status OCs,reflecting both the global shift away from chlorinated chemicals over the past 50 years and the widespread use of brominated flame retardants within the past two decades.No significant mean concentration differences were detected between 1993 and 2013 for total organochlorines(SOCs)(266 and 294 ng/g,respectively),or total polybrominated diphenyl ethers(SPBDEs)(1377 and 1521 ng/g,respectively),indicating the enduring environmental presence of these pollutants.Recently phased out PBDEs were detected at five times greater concentrations than phased out OCs.The presence of all analytes in vibrissae indicate that there is an adaptive advantage to partitioning contaminants into this inert tissue,suggesting keratinous tissue is a reliable matrix for assessing long-term for POP exposure and introducing the potential for less invasive sampling for future monitoring efforts.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.30571678 and No.30771947)the Natural Science Foundation of Jiangsu Province(No.BK2007248)
文摘Hypertrichosis is one of the most common side effects of systemic cyclosporine A therapy.It has been previously shown that cyclosporine A induces anagen and inhibits catagen development in mice.In the present study,to explore the mechanisms of cyclosporine A,we investigated the effects of cyclosporine A on hair shaft elongation,hair follicle cell proliferation,apoptosis,and mRNA expression of selected growth factors using an organ culture model of mouse vibrissae.In this model,cyclosporine A stimulated hair growth of normal mouse vibrissae follicles by inhibiting catagen-like development and promoting matrix cell proliferation.In addition,cyclosporine A caused an increase in the expression of vascular endothelial growth factor（VEGF）,hepatocyte growth factor（HGF）,and nerve growth factor（NGF）,and inhibited follistatin expression.Our findings provide an explanation for the clinically observed effects of cyclosporine A on hair growth.The mouse vibrissae organ culture offers an attractive model for identifying factors involved in the modulation of hair growth.
文摘The Structure of mammalian vibrissa was observed microscopically and the relationship of morphologyand function was discussed. The vibrissa is conical. The elasticity and tenacity of vibrissa are stronger than that ofpelage hair. The scales are shaped irregular on vibrissa shaft except for the root part, because of tractional damages. This type of scales is of great importance in preventing the vibrissa from being totally destroyed. Cortex ofvibrissa is observed very well developed, thus its elasticity and tenacity work well in touching and sensing. Medullaof vibrissa is not well developed because vibrissa has been evaluated to fail in warm-keeping function.
文摘A mathematical model of vibrissa motoneurons (vMN), which has been developed by Harish and Golomb, can show repetitive spiking in response to a transient external stimulation. The vMN model is described by a system of nonlinear ordinary differential equations based on the Hodgkin-Huxley scheme. The vMN model is regulated by various types of ionic conductances, such as persistent sodium, transient sodium, delayed-rectifier potassium, and slow ionic conductances (e.g., slowly activating potassium afterhyperpolarization (AHP) conductance and h conductance). In the present study, a numerical simulation analysis of the vMN model was performed to investigate the effect of variations in the transient sodium and the slow ionic conductance values on the response of the vMN model to a transient external stimulation. Numerical simulations revealed that when both the transient sodium and the AHP conductances are eliminated, the vMN model shows a bistable behavior (i.e., a stimulation-triggered transition between dynamic states). In contrast, none of the following induce the transition alone: 1) elimination of the transient sodium conductance;2) elimination of the AHP conductance;3) elimination of the h conductance;or 4) elimination of both the transient sodium and the h conductances.
文摘The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)since 1980.One contributing factor to the decline may be exposure to anthropogenic contaminants such as persistent organic pollutants(POPs)which are biologically accumulative in nature,toxic to organisms,and environmentally persistent.This study conducted a decadal comparison of 21 organochlorine(OC)and 39 polybrominated diphenyl ether(PBDE)analyte concentrations utilizing archived vibrissae(whiskers)from individual fur seals sampled in 1993(n=30)and 2013(n=41)during subsistence harvests on the Pribilof Islands.The recently phased out PBDEs had values five times greater than the legacy status OCs,reflecting both the global shift away from chlorinated chemicals over the past 50 years and the widespread use of brominated flame retardants within the past two decades.No significant mean concentration differences were detected between 1993 and 2013 for total organochlorines(SOCs)(266 and 294 ng/g,respectively),or total polybrominated diphenyl ethers(SPBDEs)(1377 and 1521 ng/g,respectively),indicating the enduring environmental presence of these pollutants.Recently phased out PBDEs were detected at five times greater concentrations than phased out OCs.The presence of all analytes in vibrissae indicate that there is an adaptive advantage to partitioning contaminants into this inert tissue,suggesting keratinous tissue is a reliable matrix for assessing long-term for POP exposure and introducing the potential for less invasive sampling for future monitoring efforts.
