Tomohisa Hirobe

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In order to clarify the time of onset of the differentiation of epidermal melanoblasts and melanocytes in C57BL/ 10J mice, pieces of skin were excised on various days after gestation and subjected to the dopa reaction and to the combined dopa- premelanin reaction. Cells positive to the combined dopa- premelanin reaction ( melanoblast -melanocyte population)(More)
A high frequency of X-Y chromosome dissociation (95%) was found at first meiotic metaphase (MI) in spermatocytes of interspecific hybrids between laboratory mice, C57BL/6J (BL/6) and Mus spretus, compared with an X-Y dissociation frequency of only 3-4% in parental mice. The X-Y dissociation in F1 hybrids occurred before diakinesis rather than as a(More)
Melanocytes characterized by the activities of tyrosinase, tyrosinase-related protein (TRP)-1 and TRP-2 as well as by melanosomes and dendrites are located mainly in the epidermis, dermis and hair bulb of the mammalian skin. Melanocytes differentiate from melanoblasts, undifferentiated precursors, derived from embryonic neural crest cells. Because hair bulb(More)
Coat colors are determined by melanin (eumelanin and pheomelanin). Melanin is synthesized in melanocytes and accumulates in special organelles, melanosomes, which upon maturation are transferred to keratinocytes. Melanocytes differentiate from undifferentiated precursors, called melanoblasts, which are derived from neural crest cells. Melanoblast/melanocyte(More)
  • T Hirobe
  • Histology and histopathology
  • 1995
Melanocytes characterized by their tyrosinase activity, melanosomes and dendrites locate in the basal layer of epidermis and hair bulb in the skin of mice. Melanocytes differentiate from undifferentiated melanoblasts derived from embryonic neural crest. Melanocyte-stimulating hormone plays an important role in the regulation of the differentiation of mouse(More)
Basic fibroblast growth factor (bFGF) stimulated the sustained proliferation of mouse epidermal melanoblasts derived from epidermal cell suspensions in a serum-free medium supplemented with dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP). The melanoblasts could be subcultured in the serum-free medium supplemented with the two factors in the presence(More)
  • T Hirobe
  • The journal of investigative dermatology…
  • 2001
Mouse epidermal melanoblasts preferentially proliferated from disaggregated epidermal cell suspensions derived from newborn mouse skin in serum-free melanoblast-defined medium (MDM). After 14 d, almost all keratinocytes that existed predominantly in the early stage of primary culture died, and pure cultures of melanoblasts were obtained. Epidermal(More)
When epidermal cell suspensions derived from 0.5-, 2.5-, and 4.5-day-old mice were plated onto uncoated polystyrene dishes and cultured with serum-free medium supplemented with dibutyryl cyclic adenosine 3',5'-monophosphate and basic fibroblast growth factor, melanoblasts proliferated dramatically around keratinocyte colonies and after 12-14 days pure and(More)
Mammalian melanins exist in two chemically distinct forms: the brown to black eumelanins and the yellow to reddish pheomelanins. Melanogenesis is influenced by a number of genes, the levels of whose products determine the quantity and quality of the melanins produced. To examine the effects of various coat-color genes on the chemical properties of melanins(More)
The number of melanocytes positive to the dopa reaction in the epidermis was shown to increase after newborn mice were injected with alpha-MSH or DBc-AMP. The agents seemed to induce the initiation of melanogenesis in the pre-existing melanoblasts. Electron-microscopic observation also demonstrated that alpha-MSH induced not only maturation of melanosomes(More)