Visual functions undergo an age-related degradation. However, the neural mechanisms underlying these changes are not yet clear. This study was designed to investigate the influence of age and sex on the anatomy of the...Visual functions undergo an age-related degradation. However, the neural mechanisms underlying these changes are not yet clear. This study was designed to investigate the influence of age and sex on the anatomy of the rat＇s visual cortex. Dendritic tree extent and spine density were examined in young adult rats （2-3 months） and aged male and female rats （22-24 months） using a modified Golgi-Cox staining method. A sex difference in dendritic branching of the pyramidal cells was found among young adults. However, this difference disappeared during aging, due to a reduction in branching with age for males but not for females. Moreover, the pyramidal cells of young males also have a greater spine density. Although there was a reduction in spine density with age for both sexes, this reduction was more pronounced for males, resulting in a disappearance of sex difference with age. Thus these results suggest that aging could lead to the degeneration of dendrites, which might contribute to the degradation of age-related visual functions. Also the results indicate that age-related degeneration of dendrites is more severe for males than for females.展开更多
Objective: To investigate the effect of arsenic trioxide(As_2O_3)with three different concentration groups on the distribution and recruitment of dendritic cells(DCs)in the conducting airways of asthmatic mice. Metho...Objective: To investigate the effect of arsenic trioxide(As_2O_3)with three different concentration groups on the distribution and recruitment of dendritic cells(DCs)in the conducting airways of asthmatic mice. Methods: Fifty BALB/c mice were divided into 5 groups at random:control group,asthmatic group,therapeutic groups with low dose(1 mg/kg),moderate dose(5 mg/kg)and high dose(10 mg/kg)of As_2O_3.The immunohistochemistry,scanning electron microscope and computerized image analysis were applied to detect airway DCs,respectively. Results: We demonstrated from the control mice that all intraepithelial NLDC-145 + DCs throughout the respiratory tree could be accounted for a network of cells with dendritic cell morphology,and the density of DCs varied from(500±50)cells/mm 2 epithelial surface in the large airways,to(60±10)cells/mm 2 epithelial surface in the small airways(P<0.05).The DCs characteristic of spiny and long processes were impressively observed by the scanning electron microscope.Compared with the control mice,the density,but not the distribution of NLDC-145 + DCs was significantly upregulated in the conducting airways of asthmatic mice(P<0.01).Compared with the asthmatic mice,the densities,but not the distributions of NLDC-145 + DCs were significantly down regulated in the conducting airways of the therapeutic groups with three varying concentrations of As_2O_3(P<0.01)while there were no statistical differences between each other(P>0.05). Conclusion: Our findings suggest that it might be an important therapeutic mechanism of As_2O_3 to downregulate not the distribution but the density of DCs in the conducting airways of asthmatic mice,and low dose of As_2O_3 has potential value in treating asthma.展开更多
Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwo...Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwood, transition zone and sapwood at four cardinal directions and a wider sapwood and a narrower heartwood were noted in fast grown trees than in slowly grown ones. Earlywood generally showed a higher percentage of aspirated pits than latewood regardless of the age and growth conditions of the trees in addition , the earliest dead cells and the last living cells in the marginal cells were found a bit earlier than those in the central cells. It thus seems appropriate to conclude that the death of cells results largely from decrease of fluid permeability as the number of aspirated pits increases during aging process.展开更多
基金This project was supported by grants fromthe National Natural Science Foundation of China(30520120072)National Basic Research Program(2006CB500804)Foundation of New Century Excellent Talents(NCET-04-0586).
文摘Visual functions undergo an age-related degradation. However, the neural mechanisms underlying these changes are not yet clear. This study was designed to investigate the influence of age and sex on the anatomy of the rat＇s visual cortex. Dendritic tree extent and spine density were examined in young adult rats （2-3 months） and aged male and female rats （22-24 months） using a modified Golgi-Cox staining method. A sex difference in dendritic branching of the pyramidal cells was found among young adults. However, this difference disappeared during aging, due to a reduction in branching with age for males but not for females. Moreover, the pyramidal cells of young males also have a greater spine density. Although there was a reduction in spine density with age for both sexes, this reduction was more pronounced for males, resulting in a disappearance of sex difference with age. Thus these results suggest that aging could lead to the degeneration of dendrites, which might contribute to the degradation of age-related visual functions. Also the results indicate that age-related degeneration of dendrites is more severe for males than for females.
文摘Objective: To investigate the effect of arsenic trioxide(As_2O_3)with three different concentration groups on the distribution and recruitment of dendritic cells(DCs)in the conducting airways of asthmatic mice. Methods: Fifty BALB/c mice were divided into 5 groups at random:control group,asthmatic group,therapeutic groups with low dose(1 mg/kg),moderate dose(5 mg/kg)and high dose(10 mg/kg)of As_2O_3.The immunohistochemistry,scanning electron microscope and computerized image analysis were applied to detect airway DCs,respectively. Results: We demonstrated from the control mice that all intraepithelial NLDC-145 + DCs throughout the respiratory tree could be accounted for a network of cells with dendritic cell morphology,and the density of DCs varied from(500±50)cells/mm 2 epithelial surface in the large airways,to(60±10)cells/mm 2 epithelial surface in the small airways(P<0.05).The DCs characteristic of spiny and long processes were impressively observed by the scanning electron microscope.Compared with the control mice,the density,but not the distribution of NLDC-145 + DCs was significantly upregulated in the conducting airways of asthmatic mice(P<0.01).Compared with the asthmatic mice,the densities,but not the distributions of NLDC-145 + DCs were significantly down regulated in the conducting airways of the therapeutic groups with three varying concentrations of As_2O_3(P<0.01)while there were no statistical differences between each other(P>0.05). Conclusion: Our findings suggest that it might be an important therapeutic mechanism of As_2O_3 to downregulate not the distribution but the density of DCs in the conducting airways of asthmatic mice,and low dose of As_2O_3 has potential value in treating asthma.
文摘Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwood, transition zone and sapwood at four cardinal directions and a wider sapwood and a narrower heartwood were noted in fast grown trees than in slowly grown ones. Earlywood generally showed a higher percentage of aspirated pits than latewood regardless of the age and growth conditions of the trees in addition , the earliest dead cells and the last living cells in the marginal cells were found a bit earlier than those in the central cells. It thus seems appropriate to conclude that the death of cells results largely from decrease of fluid permeability as the number of aspirated pits increases during aging process.
