| macrophage-activating factor | An agent that stimulates macrophages to attack and ingest cancer cells. They are secreted by stimulated lymphocytes that prime macrophages to become non-specifically cytotoxic to tumours. They also modulate the expression of macrophage cell surface ia antigens. One maf is interferon-gamma (interferon type II). Other factors antigenically distinct from ifn-gamma have also been identified. (12 Dec 1998) |
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| macrophage colony-stimulating factor | <growth factor> A glycoprotein growth factor that causes the committed cell line to proliferate and mature into macrophages. A cytokine synthesised by mesenchymal cells that stimulates pluripotent stem cells of bone marrow into differentiating towards the production of monocytes (mononuclear phagocytes). The compound stimulates the survival, proliferation, and differentiation of haematopoietic cells of the monocyte-macrophage series. It is a disulfide-bonded glycoprotein dimer with a mw of 70 kD and binds to a single class of high affinity receptor which is identical to the product of the c-fms proto-oncogene. See: colony-stimulating factors. Chemical name: Colony-stimulating factor 1 Acronym: M-CSF (12 Dec 1998) |
| macrophage inhibition factor | <cytokine> A group of lymphokines (including a 14 kD glycoprotein) produced by activated T lymphocytes that reduces macrophage mobility and probably increases macrophage macrophage adhesion. (18 Nov 1997) |
| radiation weighting factor | In radiation protection, a factor weighting the absorbed dose of radiation of a specific type and energy for its effect on tissue. See: equivalent dose. (05 Mar 2000) |
| maise factor | <molecular biology, plant biology> A naturally occurring cytokinin, originally isolated from maize seeds. Its riboside is also a cytokinin. (18 Nov 1997) |
| mammotropic factor | <protein> Pituitary lactogenic hormone (23 kD) Synthesised on endoplasmic reticulum bound ribosomes as preprolactin that has an N terminal signal peptide that is cleaved from the mature form. The conversion of preprolactin to prolactin has been much used as an assay for membrane insertion. (18 Nov 1997) |
| receptors, atrial natriuretic factor | Cell surface proteins that bind atrial natriuretic factor with high affinity and trigger intracellular changes influencing the behaviour of cells. (12 Dec 1998) |
| receptors, colony-stimulating factor | Cell surface receptors for colony-stimulating factors, local mediators, and hormones that regulate the survival, proliferation, and differentiation of haemopoietic cells. (12 Dec 1998) |
| receptors, granulocyte-colony-stimulating factor | Receptors that bind and internalise granulocyte-colony-stimulating factor. Their mw is believed to be 150 kD. These receptors are found mainly on a subset of myelomonocytic cells. (12 Dec 1998) |
| receptors, granulocyte-macrophage colony-stimulating factor | Receptors that bind and internalise the granulocyte-macrophage stimulating factor. Their mw is believed to be 84 kD. The most mature myelomonocytic cells, specifically human neutrophils, macrophages, and eosinophils, express the highest number of affinity receptors for this growth factor. (12 Dec 1998) |
| receptors, macrophage colony-stimulating factor | Glycoproteins of mw 165 kD which are encoded by the c-fms proto-oncogene. The binding of csf-1 to its receptors activates an intrinsic tyrosine kinase activity resulting in autophosphorylation of the receptors on tyrosine, rapid receptor down-regulation, and phosphorylation of as yet unidentified physiologic substrates that initiate a mitogenic response. (12 Dec 1998) |
| receptors, tumour necrosis factor | Cell surface receptors that bind tumour necrosis factor and trigger changes which influence the behaviour of cells. The two recognised tumour necrosis factor receptors are designated alpha and beta receptors. Both receptors bind both alpha and beta tumour necrosis factors with high affinity, and both are members of the nerve growth factor receptor family. (12 Dec 1998) |
| G factor | The single common variance or factor that is common to (i.e., empirically intercorrelates with) different intelligence tests (general). A substance required for the growth of a specific organism. (05 Mar 2000) |
| Castle's intrinsic factor | A mucoprotein normally secreted by the epithelium of the stomach and that binds vitamin B12, the intrinsic factor/B12 complex is selectively absorbed by the distal ileum, though only the vitamin is taken into the cell. (18 Nov 1997) |
| maturation factor | <biochemistry> Member of the water soluble B vitamin group, important in the proper function of the nervous system and important in proper carbohydrate, protein and fat metabolism. (27 Sep 1997) |