Despite the significant advances in regenerative medicine, wound healing has remained a challenging clinical problem. Skin is the largest human organ with many vital functions; therefore, any damage to its normal structure should be... more
Despite the significant advances in regenerative medicine, wound healing has remained a challenging clinical problem. Skin is the largest human organ with many vital functions; therefore, any damage to its normal structure should be treated as soon as possible. Easy access to skin stem cells has created a lot of excitement in therapeutic applications. “Cell therapy” is considered a novel method in regenerative medicine, especially when conventional treatments fail. Candidate cell populations for therapeutic applications include embryonic, induced pluripotent, adult mesenchymal, and hair follicle stem cells. It is possible to differentiate stem cells separated from the bulge area of hair follicle into neurons, melanocytes, keratinocytes, glia and smooth muscle cells that are negative for the keratinocyte marker kr15. This review discusses the plasticity of skin stem cells, especially stem cells located in the hair follicle and their involvement in wound healing, gene expression profile in wound healing, hair follicle stem cells, and their surrounding epidermis. Moreover, the ability of hair follicle stem cells for treating wounds and regenerative medicine is going to be discussed. Eventually we suggest the hair follicle as an ideal source of stem cells for cell therapy and regenerative medicine because they are abundant with easy access and great differentiation ability.
We present evidence for bimodal stellar age distribution of pseudobulges of S0 galaxies as probed by the D_n(4000) index. We do not observe any bimodality in age distribution for pseudobulges in spiral galaxies. Our sample is flux limited... more
We present evidence for bimodal stellar age distribution of pseudobulges of S0 galaxies as probed by the D_n(4000) index. We do not observe any bimodality in age distribution for pseudobulges in spiral galaxies. Our sample is flux limited and contains 2067 S0 and 2630 spiral galaxies drawn from the Sloan Digital Sky Survey. We identify pseudobulges in S0 and spiral galaxies, based on the position of the bulge on the Kormendy diagram and their central velocity dispersion. Dividing the pseudobulges of S0 galaxies into those containing old and young stellar populations, we study the connection between global star formation and pseudobulge age on the u-r color-mass diagram. We find that most old pseudobulges are hosted by passive galaxies while majority of young bulges are hosted by galaxies which are star forming. Dividing our sample of S0 galaxies into early-type S0s and S0/a galaxies, we find that old pseudobulges are mainly hosted by early-type S0 galaxies while most of the pseudobu...
DESCRIPTION The centre of the Milky Way is populated with so-called super-massive black holes. In most of the papers and books about black holes at the centre of galaxies, the mass is said to be gigantic. In this paper, we will see how to... more
DESCRIPTION The centre of the Milky Way is populated with so-called super-massive black holes. In most of the papers and books about black holes at the centre of galaxies, the mass is said to be gigantic. In this paper, we will see how to calculate the mass of these super-massive black holes out of observational data, by using the Maxwell Analogy for Gravitation, and we see how to make the difference between real physical mass and apparent (fictive) mass. We discover that so-called 'super-massive black holes' do not have huge masses at all but that they have an apparent mass that can be thousands times the real mass. This suggests that the energy of such black-holes could decrease very fast in relative terms.
BACKGROUND: Gap junctions form communication compartments between cells. These channels assemble from connexin subunits. OBJECTIVE: To investigate the immunoexpression of connexin 43 (Cx43) in adult human hair follicles. METHODS: Cases... more
BACKGROUND: Gap junctions form communication compartments between cells. These channels assemble from connexin subunits.
OBJECTIVE: To investigate the immunoexpression of connexin 43 (Cx43) in adult human hair follicles.
METHODS: Cases were retrospectively obtained from our archives.
RESULTS: We identified immunoexpression of Cx43 in the matrix, the papilla, the outer root sheath, the bulge, the medulla, the cortex, the shaft and the secretory part of the sebaceous gland. There was very low expression (VLE) of Cx43 in the perifollicular sheath, the mantle and the arrector pili muscle. The internal root sheath showed high-density expression in the bulb. Such expression abruptly decreased at different points in each of its layers at the point of keratinization. The isthmus showed Cx43-positive staining in the middle layers and all along, whereas there was VLE in the two outermost layers. The infundibulum showed expression all along the middle layers, whereas it showed VLE in the 2 outermost layers and in the 2 or 3 innermost layers.
CONCLUSIONS: The bulge contains Cx43. Our results suggest that keratinization in the hair follicle is closely related to the decrease in Cx43 expression.
