Skin color, melanin, and erythema

Olson, R. L.

doi:10.1001/archderm.108.4.541

Cited by 43 publications

(41 citation statements)

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“…Differences in fur color among mice are related in part to the size and shape of melanosomes (17,18). A recent report (19) indicates that dark-skinned blacks have significantly larger melanosomes than whites or lightskinned blacks. Although there are no significant differences in melanocyte distribution between the different races, blacks have more melanosomes than whites (16).…”

Section: Resultsmentioning

confidence: 99%

Tyrosinase activity in human skin. Influence of race and age in newborns.

Pomerantz¹,

Ances²

1975

J. Clin. Invest.

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A B S T R A C T Tyrosinase has been measured in homogenates of foreskins from newborn babies. The tyrosine hydroxylation reaction is dependent upon 3,4-dihydroxyphenylalanine as a cosubstrate, and the K. for tyrosine is 0.15 mM, similar to the value observed for other mammalian tyrosinases. The mean enzyme activity for black babies (n = 169) is about two and one-fourth times that for white babies (n = 82). For white babies there is a significant correlation between age at circumcision and tyrosinase activity. For black babies this correlation becomes significant when four individuals with extremely high tyrosinase activities are omitted from the series.INTRODUCTION Tyrosinase, present in melanosome granules within the melanocyte, catalyzes the formation of melanin, the brown or black polymeric pigment in skin, melanomas, hair, and eyes. Melanin is made by the following pathway:

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Section: Resultsmentioning

confidence: 99%

Tyrosinase activity in human skin. Influence of race and age in newborns.

Pomerantz¹,

Ances²

1975

J. Clin. Invest.

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“…Histol ogy and electron microscopy have clearly shown that hyperpigmentation was due to an increased epidermal mel anin content. The melanosomes were normal, although increased in size with a distribution pattern (table I ) which differed according to the degree of hyperpigmentation [11,14], Biopsy I showed that almost 50% of mature melano somes in kératinocytes were large and separate; in biopsy 3 ( fig.8b) the number and size were the greatest (table 1 ); inversely, biopsy 2 exhibited the largest number of melanosome complexes containing smaller aggregated melano somes, characteristic of Caucasian skin 115, I6| and mela nin macroglobules, which are usually a response to exces sive melanosome production in normal or pathological con ditions [17][18][19], These features were constantly observed in published cases (table 2). Melanosome size in epidermal melanocytes is under genetic control, but nongenetic factors [20J also exert an effect on the size/aggregation phenomenon in kéra tinocytes [11.…”

Section: Discussionmentioning

confidence: 99%

Progressive Hyperpigmentation: Case Report with a Clinical, Histological, and Ultrastructural Investigation

et al. 1994

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A clinical, histological and ultrastructural study of a 38-year-old woman with generalized progressive hyperpigmentation is reported. Hyperpigmentation started in early infancy, progressed during childhood and has increased to a dark bronze-brown color with ‘mottling’ in the last 8 years. Histology and electron microscopy revealed epidermal hypermelanosis and ‘negroid’ distribution of melanosomes in keratinocytes. In our family, autosomal dominant phenotype transmission with ‘variable expression’ is suggested. The literature on the entity has been reviewed. This case is another rare example of familial progressive hyperpigmentation.

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“…25 This model, capable of predictively simulating both the spectral and spatial distributions of light interacting with the skin tissues, takes into account the detailed layered structure of these tissues and the particle nature of their main light attenuation agents, namely the melanosomes, the organelles encapsulating melanin in an aggregated form. 26 In fact, it employs a first principles simulation approach that incorporates all main light absorbers (keratin, DNA, uranic acid, melanins, hemoglobins, beta-carotene, bilirubin, lipids, and water) and scatterers (cells, collagen fibers, melanosomes, and melanosome complexes) acting within the skin tissues in the ultraviolet (UV) (250 to 400 nm), visible (400 to 700 nm), and near-infrared (NIR) (700 to 2500 nm) domains.…”

Section: Simulation Framework Overviewmentioning

confidence: 99%

Assessing the sensitivity of human skin hyperspectral responses to increasing anemia severity levels

2015

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Abstract. Anemia is a prevalent medical condition that seriously affects millions of people all over the world. In many regions, not only its initial detection but also its monitoring are hindered by limited access to laboratory facilities. This situation has motivated the development of a wide range of optical devices and procedures to assist physicians in these tasks. Although noticeable progress has been achieved in this area, the search for reliable, low-cost, and risk-free solutions still continues, and the strengthening of the knowledge base about this disorder and its effects is essential for the success of these initiatives. We contribute to these efforts by closely examining the sensitivity of human skin hyperspectral responses (within and outside the visible region of the light spectrum) to reduced hemoglobin concentrations associated with increasing anemia severity levels. This investigation, which involves skin specimens with distinct biophysical and morphological characteristics, is supported by controlled in silico experiments performed using a predictive light transport model and measured data reported in the biomedical literature. We also propose a noninvasive procedure to be employed in the monitoring of this condition at the point-of-care.

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Skin color, melanin, and erythema

Cited by 43 publications

References 0 publications

Tyrosinase activity in human skin. Influence of race and age in newborns.

Tyrosinase activity in human skin. Influence of race and age in newborns.

Progressive Hyperpigmentation: Case Report with a Clinical, Histological, and Ultrastructural Investigation

Assessing the sensitivity of human skin hyperspectral responses to increasing anemia severity levels

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