| clear layer of epidermis | A layer of lightly staining corneocytes in the deepest level of the stratum corneum; found primarily in the thick epidermis of the palmar and plantar skin. Synonym: clear layer of epidermis. (05 Mar 2000) |
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| adenocarcinoma, clear cell | An adenocarcinoma characterised by the presence of varying combinations of clear and hobnail-shaped tumour cells. There are three predominant patterns described as tubulocystic, solid, and papillary. These tumours, usually located in the female reproductive organs, have been seen more frequently in young women since 1970 as a result of the association with intrauterine exposure to diethylstilbestrol. (12 Dec 1998) |
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| anterior clear space | On lateral chest radiographs, the region dorsal to the sternum and ventral to the ascending aorta. Synonym: anterior clear space. (05 Mar 2000) |
| clear cell | A cell in which the cytoplasm appears empty with the light microscope, as occurs in certain secretory cells of eccrine sweat glands and in the parathyroid glands when the glycogen is unstained, any cell, particularly a neoplastic one, containing abundant glycogen or other material that is not stained by haematoxylin or eosin, so that the cell cytoplasm is very pale in routinely stained sections. (05 Mar 2000) |
| clear cell acanthoma | A sharply demarcated benign epidermal lesion of a leg or arm with acanthosis and accumulation of glycogen in keratinocytes having pale staining cytoplasm. (05 Mar 2000) |
| clear cell adenocarcinoma | <tumour> A histologic type of renal adenocarcinoma. A histologic type of adenocarcinoma occurring chiefly in the male and female genitourinary tracts which is characterised by distinctive hobnail cell growth of neoplastic cells in sheets, papillae, and coalescing glands. (05 Mar 2000) |
| clear cell carcinoma of kidney | <radiology> Hypernephroma, renal cell carcinoma, arises from proximal collecting tubule, 10% bilateral adenocarcinoma types: papillary, alveolar, onchocytoma vascularity, 85% hypervascular (require pre-op embolization), 10% hypovascular (usually papillary type), 5% avascular associated with: tuberous sclerosis, von Hippel-Lindau syndrome see also: staging (12 Dec 1998) |
| clear cell hidradenoma | <tumour> A tumour derived from eccrine sweat glands, composed of glycogen-rich clear cells. Synonym: eccrine acrospiroma, nodular hidradenoma. (05 Mar 2000) |
| clear liquid diet | A diet, often used postoperatively, consisting usually of water, tea, coffee, gelatin preparations, and clear soups or broth. (05 Mar 2000) |
| water-clear cell of parathyroid | A variety of chief cell, so-called because the cytoplasm contains much glycogen that is not preserved or stained in the usual preparation. Synonym: wasserhelle cell. (05 Mar 2000) |
| sarcoma, clear cell | A sarcoma of young, often female, adults of the lower extremities and acral regions, intimately bound to tendons as circumscribed but unencapsulated melanin-bearing tumours of neuroectodermal origin. An ultrastructural finding simulates flattened and curved barrel staves, corresponding to the internal structures of premelanosomes. There is a 45-60% mortality in clear cell sarcoma. (12 Dec 1998) |
| A layer | <molecular biology> Right handed double helical DNA with approximately 11 residues per turn. Planes of base pairs in the helix are tilted 20 deg away from perpendicular to the axis of the helix. Formed from B DNA by dehydration. (18 Nov 1997) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| anterior elastic layer | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| anterior layer of rectus abdominis sheath | The portion of the rectus sheath that lies anterior to the muscle, consisting in its upper two-thirds of contributions from the aponeuroses of the external and internal oblique muscles, and in its lower third (below the arcuralt line) of contributions from the aponeuroses of all three muscles of the anterolateral abdominal wall. Synonym: lamina anterior vaginae musculi recti abdominis. (05 Mar 2000) |
| anterior limiting layer of cornea | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |