| lymphoma, large-cell | A form of malignant lymphoma in which the malignant cells resemble histiocytes morphologically but are presently considered to be derived from lymphoid elements. These cells are irregular in shape with relatively abundant, frequently acidophilic cytoplasm. Large-cell lymphoma can occur in both nodular (follicular) and diffuse forms, with the latter being more frequently seen. (12 Dec 1998) |
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| lymphoma, large-cell, diffuse | Malignant lymphoma composed of large cells which may be both cleaved and noncleaved. The pattern is predominantly diffuse. most of these lymphomas represent the malignant counterpart of B-lymphocytes at midstage in the process of differentiation. (12 Dec 1998) |
| lymphoma, large-cell, follicular | Malignant lymphoma in which the majority of neoplastic cells within the follicles are large cleaved or noncleaved cells. The degree to which the follicular centre cells retain their ability to form follicles varies with the state of B-cell transformation. (12 Dec 1998) |
| lymphoma, large-cell, immunoblastic | Malignant lymphoma characterised by the presence of immunoblasts with uniformly round-to-oval nuclei, one or more prominent nucleoli, and abundant cytoplasm. This class may be subdivided into plasmacytoid and clear-cell types based on cytoplasmic characteristics. A third category, pleomorphous, may be analogous to some of the peripheral T-cell lymphomas (lymphoma, T-cell, peripheral) recorded in both the united states and japan. (12 Dec 1998) |
| lymphoma, large-cell, ki-1 | A large-cell, non-hodgkin's, malignant lymphoma with pleomorphic appearance and reactivity with the monoclonal antibody ki-1. The lymphoma is most often found in the skin and lymph nodes and expresses the ki-1 (CD30) antigen (antigens, CD30) on its surface. It is often mistaken for metastatic carcinoma and malignant histiocytosis. (12 Dec 1998) |
| alveolar dead space | The difference between physiologic dead space and anatomical dead space; it represents that part of the physiologic dead space resulting from ventilation of relatively underperfused or nonperfused alveoli; it differs specifically in being placed so as to fill and empty in parallel with functional alveoli, rather than being interposed in the conducting tubes between functional alveoli and the external environment. (05 Mar 2000) |
| anatomical dead space | The volume of the conducting airways from the external environment (at the nose and mouth) down to the level at which inspired gas exchanges oxygen and carbon dioxide with pulmonary capillary blood; formerly presumed to extend down to the beginning of alveolar epithelium in the respiratory bronchioles, but more recent evidence indicates that effective gas exchange extends some distance up the thicker-walled conducting airways because of rapid longitudinal mixing. Compare: alveolar dead space, physiologic dead space. Synonym: anatomical airway. (05 Mar 2000) |
| antecubital space | The fossa in front of the elbow, bounded laterally and medially by the humeral origins of the extensors and flexors of the forearm, respectively, and superiorly by an imaginary line connecting the humeral condyles. Synonym: fossa cubitalis, antecubital space, chelidon, triangle of elbow. (05 Mar 2000) |
| 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) |
| apical space | The space between the alveolar wall and the apex of the root of a tooth where an alveolar abscess usually has its origin. (05 Mar 2000) |
| axillary space | <anatomy> The underarm area. (16 Dec 1997) |
| Berger's space | The space between the patellar fossa of the vitreous and the lens. (05 Mar 2000) |
| Bogros' space | A triangular space between the peritoneum and the transversalis fascia, at the lower angle of which is the inguinal ligament; it contains the lower portion of the external iliac artery. Synonym: Bogros' space, spatium retroinguinale. (05 Mar 2000) |
| Bottcher's space | The blind pouch at the end of the endolymphatic duct. (12 Dec 1998) |
| Bowman's space | The slitlike space between the visceral and parietal layers of the capsule of the renal corpuscle; it opens into the proximal tubule of the nephron at the neck of the tubule. Synonym: Bowman's space, filtration space. (05 Mar 2000) |