| platelet-derived growth factor | <growth factor> The major mitogen in serum for growth in culture of cells of connective tissue origin. It consists of 2 different but homologous polypeptides A and B (~30,000 D) linked by disulphide bonds. Believed to play a role in wound healing. It is carried in the alpha-granules of platelets and is released when platelets adhere to traumatised tissues. Connective tissue cells near the traumatised region respond by initiating the process of replication. The B chain is almost identical in sequence to p28sis, the transforming protein of simian sarcoma virus, that can transform only those cells that express receptors for platelet derived growth factor, suggesting that transformation is caused by autocrine stimulation. The receptor is a tyrosine kinase. Acronym: PDGF (12 Dec 1998) |
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| multiplicative growth | Growth by an increase in the number of cells. (05 Mar 2000) |
| contact inhibition of growth | See: density dependent inhibition. (18 Nov 1997) |
| population growth | <epidemiology> Increase, over a specific period of time, in the number of individuals living in a country or region. (12 Dec 1998) |
| haematopoietic cell growth factors | These growth factors comprise a family of haematopoietic regulators with biological specificities defined by their ability to support proliferation and differentiation of blood cells of different lineages. Erythropoietin and the colony-stimulating factors belong to this family. Some of these factors have been studied and used in the treatment of chemotherapy-induced neutropenia, myelodysplastic syndromes, and bone marrow failure syndromes. (12 Dec 1998) |
| sarcoma growth factor | <growth factor> Polypeptide released by sarcoma cells that promotes the growth of cells by binding to a cell surface receptor, the sarcoma cell is therefore self sufficient and independent of normal growth control. See: growth factors. The name is no longer commonly used. (18 Nov 1997) |
| heparin binding growth factor | <growth factor> Acidic fibroblast growth factor (alpha FGF, HBGF 1) and basic FGF (beta FGF, HBGF 2) are the two founder members of a family of structurally related growth factors for mesodermal or neuroectodermal cells. Synonym: heparin binding growth factor. Acronym: FGF (18 Nov 1997) |
| hepatocyte growth factor | <growth factor> Polypeptide mitogen originally shown to cause cell division in hepatocytes. In the liver, the main sources of hepatocyte growth factor are nonparenchymal cells. It is now clear that hepatocyte growth factor is a mitogen for a number of cell types and it is found in many cells outside the liver, including platelets. Hepatocyte growth factor is synthesised as a single chain precursor that is proteolytically cleaved to give a heavy chain (70 kD) and a light chain (30 kD) linked by a single disulphide bond. It contains multiple copies of the kringle domain. However, both the single chain precursor and the two chain forms of hepatocyte growth factor are biologically active and hepatocyte growth factor is generally isolated as a mixture of the two forms. Hepatocyte growth factor also alters cell motility and is now known to be identical to scatter factor. Acronym: HGF (18 Nov 1997) |
| schwannoma derived growth factor | <growth factor> A growth factor containing an EGF like domain, mitogenic for astrocytes, Schwann cells and fibroblasts. (18 Nov 1997) |
| second growth | A second generation of timber of merchantable age. (05 Dec 1998) |
| horizontal growth phase | An early stage of development of cutaneous melanoma by intraepidermal spread of atypical melanocytes. (05 Mar 2000) |
| human growth hormone | <endocrinology> A protein produced in the pituitary gland that stimulates the liver to produce somatomedins, which stimulate growth of bone and muscle. (09 Oct 1997) |
| stem cell growth factors | <growth factor> Compounds, usually proteins, that make stem cells grow faster. (26 Mar 1998) |
| nerve growth cone | <cell biology> A specialised region at the tip of a growing neurite that is responsible for sensing the local environment and moving toward the neuron's target cell. Growth cones are hand shaped, with several long filopodia that differentially adhere to surfaces in the embryo. Growth cones can be sensitive to several guidance cues, for example: surface adhesiveness, growth factors, neurotransmitters and electric fields (galvanotropism). (18 Nov 1997) |
| nerve growth factor | <growth factor> A peptide (13.26 kD) of 118 amino acids (usually dimeric) with both chemotropic and chemotrophic properties for sympathetic and sensory neurons. Found in a variety of peripheral tissues, nerve growth factor attracts neurites to the tissues by chemotropism, where they form synapses. The successful neurons are then protected from neuronal death by continuing supplies of nerve growth factor. It is also found at exceptionally high levels in snake venom and male mouse submaxillary salivary glands, from which it is commercially extracted. Nerve growth factor was the first of a family of nerve tropic factors to be discovered. Amino acids 1-81 show homology with proinsulin. Besides its peripheral actions, nerve growth factor selectively enhances the growth of cholinergic neurons that project to the forebrain and that degenerate in Alzheimer's disease. Acronym: NGF (18 Nov 1997) |