A Critical Review of Pigment Research in the Last Hundred Years.

Meirowsky, E.

doi:10.1111/j.1365-2133.1940.tb09916.x

Cited by 27 publications

(2 citation statements)

References 8 publications

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“…A number of investigators (e.g., Ehrmann, 1885) believed the pigment cells in the epidermis were "fixed connective tissue cells" that either penetrated the epidermis or were present as modified epithelial cells. Ito (1953) stated that the epidermal pigment cells originated from nervous tissue, and Bloch (1921) and Mierowsky (1940) (among others) ascribed an ectodermal origin to the epidermal melanocyte and suggested that they were modified basal cells. Mierowsky recognized, however, that this population of dendritic cells differed from surrounding keratinocytes in morphology, ability to divide, and organization within the epithelium.…”

Section: Studies Of Pigmentation In Human Fetal Skinmentioning

confidence: 99%

Melanocytes in Human Embryonic and Fetal Skin: A Review and New Findings

Holbrook

Vogel

Underwood

et al. 1988

Pigment Cell Research

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Melanocytes account for approximately &lo% 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 pig mentation. 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; 46263-277). 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 nonrandom 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 these questions.Definitions: Menstrual age (MA) = age of the fetus measured from the time of the last known menstrual period Estimated gestation age (EGA) = age of the fetus measured from the calculated date of ...

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Section: Studies Of Pigmentation In Human Fetal Skinmentioning

confidence: 99%

Melanocytes in Human Embryonic and Fetal Skin: A Review and New Findings

Holbrook

Vogel

Underwood

et al. 1988

Pigment Cell Research

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“…The evidence, in mammals, supporting this view has been largely supplied by Rawles (20,21). The opposing school of workers believes that the basal cell may be transformed into a dopa-positive, dendritic cell (9,17). Allen (1,2) states that melanocytes have intercellular bridges and, quot-* Supported by grants from the United States Public Health Service A 1150 and H 2490.…”

mentioning

confidence: 99%

Electron Microscope Studies of the Human Epidermis The Clear Cell of Masson (Dendritic Cell or Melanocyte)

Clark

Hibbs

1958

The Journal of Cell Biology

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The human epidermis has been studied by electron microscopy following osmium tetroxide and potassium permanganate fixation. An anatomically distinct cell in the human epidermis has been demonstrated with features similar to the melanocyte of the hair bulb described by Barnicot, Birbeck and Cuckow (3). It is dendritic in form and does not contain tonofilaments. "Intercellular bridges" are not formed. The mitochondria are larger and more numerous than those of other epidermal cells and the endoplasmic reticulum is more complex. Some of these cells contain melanin but others are melanin-free. The cell has been interpreted as being identical with the dopa-positive, clear cell of Masson (dendritic cell of Bloch or melanocyte). We have found that many membranous structures in the human epidermis are better preserved by permanganate fixation than by osmium tetroxide fixation.

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Mammalian Pigmentation

Sharlit¹

1946

Arch Derm Syphilol

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A Critical Review of Pigment Research in the Last Hundred Years.

Cited by 27 publications

References 8 publications

Melanocytes in Human Embryonic and Fetal Skin: A Review and New Findings

Melanocytes in Human Embryonic and Fetal Skin: A Review and New Findings

Electron Microscope Studies of the Human Epidermis The Clear Cell of Masson (Dendritic Cell or Melanocyte)

Mammalian Pigmentation

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