ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00787.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1987.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00788.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Melanocytes account for approximately 5–10% percent of the cells in adult epidermis. Unlike the ectodermally derived keratinocytes, they originate in the neural crest and migrate into the epidermis early in development. There has been an interest in melanocytes in developing human skin since the late 1800s, when concentrated pigmented cells were identified in the sacro‐coccygeal skin of Japanese fetuses. This observation led to speculation and subsequent investigation about the racial nature of the melanocytes in this site (the Mongolian spot), the presence of melanocytes in fetuses of other races, the timing of appearance of these cells in both the dermis and epidermis, and their origin. The early investigators relied primarily on histochemical methods that stained either the premelanosome or the pigmented melanosome, or relied upon the activity of tyrosinase within the melanosome to effect the DOPA reaction. Studies by electron microscopy added further documentation to the presence of melanocytes in the skin by resolving the structure of the melanosome regardless of its state of pigmentation. All of these methods recognized, however, only differentiated melanocytes. The thorough investigations of melanocytes in the skin from a large number of black embryos and fetuses by Zimmerman and colleagues between 1948 and 1955 provided insight into the time of appearance of melanocytes in the dermis (10–11 weeks' menstrual age) and the epidermis (11–12 weeks) and revealed the density of these cells in both zones of the skin of several regions of the body. The precise localization of the melanocytes in the developing hair follicles was contributed by the studies of Mishima and Widlan (J Invest Dermatol 1966; 46:263–277). More recently, monoclonal antibodies have been developed that recognize common oncofetal or oncodifferentiation antigens on the surface or in the cytoplasm of melanoma cells and developing melanocytes (but not normal adult melanocytes). These antibodies recognize the cells irrespective of the presence or absence of melanosomes or their activity in the synthesis of pigment and therefore are valuable tools for re‐examining the presence, density, and distribution patterns of melanocytes in developing human skin. Using one of these antibodies (HMB‐45), it was found that dendritic melanocytes are present in the epidermis between 40 and 50 days estimated gestational age in a density comparable with that of newborn epidermis and are distributed in relatively non‐random patterns. A number of questions about the influx of cells into the epidermis, potential reservoirs of melanoblasts retained within the dermis, division of epidermal melanocytes, and the interaction of melanocytes and keratinocytes during development remain unresolved. The tools now appear to be available, however, to begin to explore many of

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00789.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

An investigation of the invasiveness of avian neural crest cells and neural crest‐derived melanocytes through a human amniotic basement membrane (BM) was undertaken. Avian neural tube explants or derived melanocyte populations were seeded directly onto BMs in membrane invasion culture system (MICS) chambers for periods of 24, 48, and 72 h. In 36 experimental trials for each group, neither neural crest nor neural crest‐derived melanocytes were observed to have invaded the BMs. In concert with these studies, coculturing of B16F10 murine melanoma cells with avian neural crest‐derived melanocytes was performed in MICS chambers. Under these experimental conditions, the neural crest‐derived melanocytes were able to successfully invade the BMs and to a greater extent than the B16F10 tumor cells. These data suggest that neural crest cells and neural crest‐derived melanocytes do not have the ability to invade the BM alone; however, they can be induced to be invasive when cocultured in the presence of B16F10 cells. Alternatively, the B16F10 cells may create weaknesses within the BM that facilitate migration of the pigmented cr

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1987.tb00529.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

To proliferate in vitro, normal melanocytes, unlike normal fibroblasts, require specific growth factors in addition to those supplied in serum. The substances that promote melanocyte proliferation, such as 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) and stimulators of cyclic adenosine monophosphate (cAMP), also promote pigmentation. Consequently, cell division and expression of at least some differentiated functions are not mutually exclusive for melanocytes. At present, the only known natural growth factor that can replace TPA in normal human melanocyte cultures is basic fibroblast growth factor (bFGF). Like TPA, bFGF is effective, most of the time, only in the presence of added cAMP. Some preparations of bFGF, however, may have a highly labile, intrinsinc cAMP stimulatory activity. It is thus possible that bFGF can assume two forms, dependent on and independent of cAMP stimulatory activity. Alternatively, a second factor may exist in pituitary glands that co‐purifies with bFGF but deteriorates with storage. Abnormal melanocytes in culture, such as those derived from dysplastic nevi and primary melanomas, depend on the specific factors (bFGF and cAMP), whereas melanocytes from metastatic mela

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00790.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

We used monoclonal antibodies and an indirect immunoperoxidase technique to identify mononuclear inflammatory cells associated with human tumors. The absolute number of the different types of inflammatory cells was assessed by using a point‐counting technique. We studied tissues from six primary cutaneous melanomas, six metastatic melanomas, eight melanocytic nevi, 14 breast cancers, seven examples of fibrocystic disease of the breast, 11 lung cancers, and six colon cancers. Virtually all tumors were associated with substantial numbers of T lymphocytes (Leu3a‐positive T helper‐inducer cells predominating) and macrophages. Primary melanomas contained significantly more T lymphocytes (P<.002), macrophages (P<.005), and Langerhans/dendritic cells (P.01). Breast cancers contained more T lymphocytes and macrophages than occur with fibrocystic disease (P<.0001 andP<.002, respectively) and more B lymphocytes. Cancers of the lung and colon contained moderate numbers of T lymphocytes and macrophages; however, colon cancers contained a higher proportion of B cells. Leu7‐positive NK/K cells were noted in small numbers in all tumors e

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1987.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

In this article we review some of our recent results on the growth of human skin cells in vitro with emphasis on the normal melanocyte. Growth in a defined culture medium of normal human melanocytes isolated from neonatal or adult skin has been achieved. Melanocytes can be routinely cultured in medium MCDB 153 (0.1 mM CaCl2) supplemented with bovine pituitary extract (BPE), insulin, ethanolamine, phosphoethanolamine, hydrocortisone, and 12‐O‐tetradecanoyl phorbol 13‐acetate (TPA). The cells can be propagated for up to 35 cumulative population doublings in this medium. Further studies have shown that the undefined component of the medium, BPE, can be replaced with purified heparin‐binding growth factor type‐2 (also known as basic fibroblast growth factor), HBGF‐2/bFGF, isolated from BPE. Neither epidermal growth factor nor trans‐forming growth factor type‐alpha could replace HBGP‐2/bFGF for the growth of melanocytes. These results are in contrast to the growth factor requirements for normal human fibroblasts or keratinocytes whose proliferation in serum‐free medium can be stimulated by either EGF or HBGF‐2/bFGF. We have examined mRNA isolated from serum‐free cultures of melanocytes, keratinocytes and fibroblasts for expression of the HBGF‐2/bFGF gene. Fibroblasts, but not melanocytes or keratinocytes, express 4 distinct transcripts which hybridize to a specific HBGF‐2/bFGF cDNA probe. Our results suggest that expression of the HBGF‐2/bFGF gene is cell‐type specific and that HBGF‐2/bFGF produced by dermal cells could support the proliferation and/or normal homeostasis of melanocytes and keratinocytes dur

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00791.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Clonal cultures were performed with the use of neural crest cells and their derivatives, chromatophores, fromXenopus laevisin order to elucidate the state of commitment in early embryogenesis. Neural crest cells that outgrew from neural tube explants were isolated and plated at clonal density. Cloned neural crest cells differentiated and gave rise to colonies that consisted of 1) only melanophores, 2) only xanthophores, or 3) melanophores and xanthophores. Xanthophores and iridophores, which differentiated in vitro, were also isolated and cloned. Cloned xanthophores proliferated in a stable fashion and did not lose their properties. On the other hand, cloned iridophores converted into melanophores as they proliferated. These results suggest that there is heterogeneity in the state of commitment of neural crest cells immediately after migration with regard to chromatophore differentiation and that iridophore determination is relatively labile (at least in vitro), whereas melanophore and xanthophore phenotypes are stable.

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1987.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Melanocytes originate from the neural crest in vertebrates and migrate to the body surface where they differentiate into functional cells. Genes involved in melanocyte differentiation can be classified into two groups. One of them consists of the functional genes that control proteins specific to the function of the melanocyte. As the representative gene of this category, albino (c) locus in the mouse is considered to control tyrosinase, the key enzyme in melanogenesis. cDNA for mouse tyrosinase has been cloned and sequenced. The cDNA can be used to detect tyrosinase mRNA synthesized during melanocyte differentiation. On the other hand, genes such as brown (b) or pink‐eyed dilution (p) have been assumed to control melanosome proteins.The other category consists of genes that regulate the expression of these functional genes directly or indirectly. In the mouse, so‐called white‐spotting genes and genes of the agouti series are considered to fall into this category. Based on the fact that mutations at the white‐spotting loci result in the absence of melanocytes in a particular area of skin, it is assumed that some of these loci control the factors that promote either differentiation or migration of melanoblasts and are candidates for the classic regulator genesGenes at the agouti (a) locus in the mouse determine the type of melanin synthesized in hair follicle melanocytes, that is eumelanin or pheomelanin. An interesting feature of this locus is that the site of gene action is not within the melanocytes but in the cells surrounding them. The results of our study indicate that the gene product of the a‐locus interacts with α‐MSH at the α‐MSH receptor site, regulates the cellular cAMP level via a signal transduction system and, in turn, determines the type of melanin synthesiz

ISSN:0893-5785    

DOI:10.1111/j.1600-0749.1988.tb00792.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY