Biomaterial Database

Spreading pigmented actinic keratosis. An electron microscopic study. 1988

S M Dinehart, and R L Sanchez

Department of Dermatology, University of Texas Medical Branch, Galveston.

Spreading pigmented actinic keratosis is a rarely reported premalignant, pigmented, epidermal tumor that can be difficult to distinguish clinically from other benign and malignant pigmented lesions. In an attempt to determine the cause of clinical hyperpigmentation, seven lesions from five patients were examined by light microscopy. Three of these lesions were also examined using electron microscopy. Findings from these studies indicate that hyperpigmentation is due to enhanced melanosome formation and distribution and not to a melanocyte-keratinocyte melanosome transfer block.

UI	MeSH Term	Description	Entries
D007633	Keratins	A class of fibrous proteins or scleroproteins that represents the principal constituent of EPIDERMIS; HAIR; NAILS; horny tissues, and the organic matrix of tooth ENAMEL. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms a coiled-coil alpha helical structure consisting of TYPE I KERATIN and a TYPE II KERATIN, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. alpha-Keratins have been classified into at least 20 subtypes. In addition multiple isoforms of subtypes have been found which may be due to GENE DUPLICATION.	Cytokeratin,Keratin Associated Protein,Keratin,Keratin-Associated Proteins,alpha-Keratin,Associated Protein, Keratin,Keratin Associated Proteins,Protein, Keratin Associated,alpha Keratin
D007642	Keratosis	Any horny growth such as a wart or callus.	Keratoderma Blennorrhagicum,Keratoma,Keratosis Blennorrhagica,Blennorrhagica, Keratosis,Blennorrhagicas, Keratosis,Blennorrhagicum, Keratoderma,Blennorrhagicums, Keratoderma,Keratoderma Blennorrhagicums,Keratomas,Keratoses,Keratosis Blennorrhagicas
D008297	Male		Males
D008544	Melanocytes	Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.	Melanocyte
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D003452	Cryosurgery	The use of freezing as a special surgical technique to destroy or excise tissue.	Cryoablation,Cryoablations,Cryosurgeries
D004817	Epidermis	The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man