| cell division phases | The stages which a cell undergoes when dividing. There are four successive phases: prophase, metaphase, anaphase, and telephase. (12 Dec 1998) |
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| cell electrophoresis | <technique> A method for estimating the surface charge of a cell by looking at its rate of movement in an electrical field. Almost all eukaryotic cells have a net negative surface charge. Measurement is complicated by the streaming potential at the wall of the chamber itself and by the fact that the cell is surrounded by a layer of fluid (see double layer). The electrical potential measured (the zeta potential) is actually some distance away from the plasma membrane. One of the more useful modifications is to systematically vary the pH of the suspension fluid to determine the pK of the charged groups responsible (mostly carboxyl groups of sialic acid). (26 Mar 1998) |
| cell extracts | Preparations of cell constituents or subcellular materials, isolates, or substances. (12 Dec 1998) |
| cell fate | <embryology> Of an embryonic parent (progenitor) cell or cell type, the range and distribution of differentiated tissues formed by its daughter cells. For example: cells of the neural crest differentiate to form among other things) cells of the peripheral nervous system. (26 Mar 1998) |
| cell fractionation | <technique> Strictly this should mean the separation of homogeneous sets from a heterogeneous population of cells (by a method such as flow cytometry). The term is more frequently used to mean subcellular fractionation i.e. The separation of different parts of the cell by differential centrifugation, to give nuclear, mitochondrial, microsomal and soluble fractions. (26 Mar 1998) |
| cell fusion | <biology, embryology> Fusion of two previously separate cells occurs naturally in fertilization and in the formation of vertebrate skeletal muscle, but can be induced artificially by the use of Sendai virus or fusogens such as polyethylene glycol. Fusion may be restricted to cytoplasm or nuclei may fuse as well. A cell formed by the fusion of dissimilar cells is often referred to as a heterokaryon. (26 Mar 1998) |
| cell growth | <cell biology> Usually used to mean increase in the size of a population of cells though strictly should be reserved for an increase in cytoplasmic volume of an individual cell. (26 Mar 1998) |
| cell hybridization | Fusion of two or more dissimilar cells, leading to formation of a synkaryon. (05 Mar 2000) |
| cell hypoxia | A condition of decreased oxygen content at the cellular level. (12 Dec 1998) |
| cell inclusions | The residual elements of the cytoplasm that are metabolic products of the cell, e.g., pigment granules or crystals. Synonym: metaplasm. Storage materials such as glycogen or fat, engulfed material such as carbon or other foreign substances. See: inclusion bodies. (05 Mar 2000) |
| cell junction | <cell biology> Specialised junctions between cells. See: adherens junctions, desmosomes, tight junctions, gap junctions. (26 Mar 1998) |
| cell line | <cell culture> A cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. Lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell. (26 Mar 1998) |
| cell line rights | <cell culture> Ownership of a new organism entity. Rulings indicate that any organism that is patentable at all can be patented if it has been manipulated to do something useful. Usually, the rights do not reside with the individual who has supplied the source of the organism, but with the individual or organisation who has made it. (26 Mar 1998) |
| cell line, transformed | Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumour. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals. (12 Dec 1998) |
| cell lineage | <cell culture, embryology> The lineage of a cell relates to its derivation from the undifferentiated tissues of the embryo. Committed embryonic progenitors give rise to a range of differentiated cells: in principle it should be possible to trace the ancestry lineage) of any adult cell. (26 Mar 1998) |
| anaplastic large cell lymphoma | <tumour> A form of lymphoma characterised by anaplasia of cells, sinusoidal growth, and immunoreactivity with CD30 (Ki-1 or Ber-H2). Synonym: Ki-1+ lymphoma. (05 Mar 2000) |
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| animal cell culture | <cell culture> Mammalian cells are fragile and harder to grow than other cell types, but their large-scale culturing is an economic boon because it allows for the production of proteins that are otherwise difficult or expensive or unethical to extract from living organisms. The cells are immobilised on a substrate and then perfused with culture medium, The cells are in a free suspension which is very gently mixed and aerated. (12 Nov 1997) |
| animal cell immobilisation | <cell culture> Animal cells are widely used in biotechnology to produce genetically engineered proteins. However, they are more fragile than bacterial cells, and immobilising the cell facilitates the fermentation process. Many animal cells stick down flat on a suitable surface, hugging it as they would hug other cells or connective matrices in the body. If grown on suitable plastic surfaces, on glass or many ceramics, these cells will stick to them. In this way, they are easier to grow. (14 Nov 1997) |
| animalised cell | <zoology> The 8-16 cell early blastula of sea urchins has animal and vegetal poles, by manipulating the environmental conditions it is possible to shift more cells from vegetal to animal in their characteristics. (12 Nov 1997) |
| Anitschkow cell | A large mononuclear cell found in connective tissue of the heart wall in inflammatory conditions, especially in the Aschoff body. The ovoid nucleus contains a central chromatin mass appearing as a wavy bar in longitudinal section. Synonym: Anitschkow cell, Anitschkow myocyte, caterpillar cell. (05 Mar 2000) |
| anterior horn cell | Synonym for motoneuron. (18 Nov 1997) |
| antibody-dependent cell cytotoxicity | The phenomenon of antibody-mediated target cell destruction by non-sensitised effector cells. The identity of the target cell varies, but it must possess surface IgG whose fc portion is intact. The effector cell is a "killer" cell possessing fc receptors. It may be a lymphocyte lacking conventional b- or T-cell markers, or a monocyte, macrophage, or polynuclear leukocyte, depending on the identity of the target cell. The reaction is complement-independent. (12 Dec 1998) |
| antibody-forming cell | <immunology> B-cells (plasma cells) that are dedicated to producing secreted antibodies. (09 Feb 1998) |
| antibody producing cell | <immunology> A lymphocyte of the B series synthesising and releasing immunoglobulin. Equivalent to plasmacyte and plasma cell. (18 Nov 1997) |
| antigen presenting cell | A cell that carries on its surface antigen bound to MCH Class I or Class II molecules and presents the antigen in this context to T-cells. Includes macrophages, endothelium, dendritic cells and Langerhans cells of the skin. See: MHC restriction, histocompatibility antigens. (18 Nov 1997) |
| antigen-responsive cell | A small lymphocyte that, although not itself an immunologically activated cell, responds to antigenic (immunogenic) stimulus by a process of division and differentiation that results in the production of immunologically activated cells. Synonym: antigen-responsive cell. (05 Mar 2000) |
| antigen-sensitive cell | A small lymphocyte that, although not itself an immunologically activated cell, responds to antigenic (immunogenic) stimulus by a process of division and differentiation that results in the production of immunologically activated cells. Synonym: antigen-responsive cell. (05 Mar 2000) |
| antiparietal cell antibody | <immunology> A serologic blood test which measures the presence of antibodies to gastric parietal cells. Less than 2% of the general population will be antibody positive although this can be higher in the elderly. Approximately 90% of individuals with pernicious anaemia will be antibody positive. A positive result may also be seen in atrophic gastritis, gastric ulcer, thyroid disease, iron deficiency anaemia and diabetes. (13 Jan 1998) |
| antipodal cell | <plant biology> Three cells of the embryo sac in angiosperms, found at the end of the embryo away from the point of entry of the pollen tube. (13 Jan 1998) |
| apolar cell | A neuron without processes. (05 Mar 2000) |