"The effects of ultraviolet irradiation on the pigment cells of the PET" by Vaughan Henry Howard Jr.

Date of Award

1973

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

Abstract

Epidermal melanocytes in mammals are known to occur in a variety of shapes, sizes, and colors. The basic melanocyte morphology is dependent upon genetics, but there are a number of environmental factors that can cause modification.

In the epidermis of PET/\vrnr mice, the population of rnelanocytes reaches a peak and begins to decline during the first post-natal week, and has disappeared within four weeks. Dispersed among the large, highly DOPA-reactive melanocytes are miniature melanocytes. These miniature melanocytes are weakly DOPA-reactive and appear early in the post-natal period. The miniature melanocyte population is relatively constant and these miniature cells are among the last to disappear.

The melanocytes of the epidermis in the PET/Hmr mouse were subjected to 3 different wavelengths of UV irradiation. Melanocyte counts of the experimental animals were compared with similar counts of control, non irradiated animals in the first post-natal week.

The evidence indicates that these weakly DOPA-reactive, miniature melanocytes remain in fairly constant numbers during the first postnatal week, although UV irradiation did provoke a very clear increase in the numbers of the larger, highly DOPA-reactive melanocytes. That miniature melanocytes persisted throughout the experimental treatments success that they may represent a separate form of melanocyte.

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Biology Commons

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