| insulin-like growth factor II | <chemical> A well-characterised neutral peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on somatotropin. It is believed to be a major foetal growth factor in contrast to insulin-like growth factor I, which is a major growth factor in adults. Chemical name: Insulin-like growth factor II (12 Dec 1998) |
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| insulin-like growth factors | Peptides whose formation is stimulated by growth hormone. These peptides bring about peripheral tissue effects of that hormone and have high (about 70%) homology to human insulin. Synonym: somatomedins. (05 Mar 2000) |
| interstitial growth | Growth from a number of different centres within an area; in contrast with appositional growth, it can occur only when the materials involved are nonrigid. (05 Mar 2000) |
| intrauterine growth retardation | <radiology> Definition: less than 10th percentile for gestational age, usually not detectable before 32-34 weeks (maximal foetal growth), incidence: 3-7% of all deliveries, 12-47% of twin pregnancies complications: increased risk for perinatal asphysia, meconium aspiration, electrolyte imbalance from metabolic acidosis, polycythemia, 6-8 fold increase for intrapartum and neonatal death see also: IUGR: aetiology, IUGR: phenotypes, foetal doppler study, biophysical profile (12 Dec 1998) |
| intussusceptive growth | Growth by increase in the size of component cells. Synonym: intussusceptive growth. (05 Mar 2000) |
| old growth | Timber stands with the following characteristics: large mature and over-mature trees in the overstory, snags, dead and decaying logs on the ground, and a multi-layered canopy with trees of several age classes. (05 Dec 1998) |
| old-growth stand | Forest stand dominated by trees reaching natural death, the last stage in forest succession. (09 Oct 1997) |
| Tanner growth chart | A series of chart's showing distribution of parameters of physical development, such as stature, growth curves, and skinfold thickness, for children by sex, age, and stages of puberty. (05 Mar 2000) |
| T-cell growth factor | <cytokine> A hormone-like substance released by stimulated T lymphocytes, causes activation and differentiation of other T lymphocytes independently of antigen. A type of interleukin, a chemical messenger, a substance that can improve the body's response to disease. It stimulates the growth of certain disease-fighting blood cells in the immune system. It is secreted by Thl CD4 cells to stimulate CD8 cytotoxic T-1yrnphocytes. Interleukin 2 also increases the proliferation and maturation of the CD4 cells themselves. During HIV infection, Interleukin-2 production gradually declines. Use of interleukin 2 therapy is under study as a way to raise CD4 cell counts and restore immune function. Acronym: IL-2 (12 Dec 1998) |
| T-cell growth factor-1 | <cytokine> A hormone-like substance released by stimulated T lymphocytes, causes activation and differentiation of other T lymphocytes independently of antigen. A type of interleukin, a chemical messenger, a substance that can improve the body's response to disease. It stimulates the growth of certain disease-fighting blood cells in the immune system. It is secreted by Thl CD4 cells to stimulate CD8 cytotoxic T-1yrnphocytes. Interleukin 2 also increases the proliferation and maturation of the CD4 cells themselves. During HIV infection, Interleukin-2 production gradually declines. Use of interleukin 2 therapy is under study as a way to raise CD4 cell counts and restore immune function. Acronym: IL-2 (12 Dec 1998) |
| T-cell growth factor-2 | <cytokine> A soluble cytokine factor produced by activated T-lymphocytes that promotes antibody production by causing proliferation and differentiation of B-cells. Interleukin-4 induces the expression of class II major histocompatibility complex and fc receptors on B-cells. It also acts on T-lymphocytes, mast cell lines, and several other haematopoietic lineage cells including granulocyte, megakaryocyte, and erythroid precursors, as well as macrophages. Acronym: IL-4 (12 Dec 1998) |
| transforming growth factor | <growth factor> Proteins secreted by transformed cells that can stimulate growth of normal cells. Unfortunate misnomer, since they induce aspects of transformed phenotype, such as growth in semi solid agar, but do not actually transform. Transforming growth factor alpha, 50 amino acid polypeptide originally isolated from viral transformed rodent cells, contains EGF like domain and binds to EGF receptor. Stimulates growth of microvascular endothelial cells, i.e. Is angiogenic. Transforming growth factor beta a homodimer of two 112 chains, polypeptide is secreted by many different cell types, stimulates wound healing but in vitro is also a growth inhibitor for certain cell types. The transforming growth factor family includes many of the bone morphogenetic proteins. Acronym: TGF (18 Nov 1997) |
| transforming growth factor alpha | Factor isolated in a variety of tissues including epithelium, and maternal decidua. It is closely related to epidermal growth factor (epidermal growth factor-urogasterone) and binds to the egf receptor. Tgf-alpha acts synergistically with tgf-beta in inducing phenotypic transformation, but its physiological role is unknown. (12 Dec 1998) |
| transforming growth factor beta | Factor synthesised in a wide variety of tissues including platelets, placenta, and both normal and transformed cell lines. It acts synergistically with tgf-alpha in inducing phenotypic transformation and can also act as a negative autocrine growth factor. Tgf-beta also has a potential role in embryonal development, cellular differentiation, hormone secretion, and immune function. There are at least three forms of tgf-beta: tgf-beta1, tgf-beta2, and tgf-beta1.2. The latter is a heterodimer made up of both tgf-beta1 and tgf-beta2. (12 Dec 1998) |
| transforming growth factors | <chemical> Hormonally active polypeptides that can induce the transformed phenotype when added to normal, non-transformed cells. They have been found in culture fluids from retrovirally transformed cells and in tumour-derived cells as well as in non-neoplastic sources. Their transforming activities are due to the simultaneous action of two otherwise unrelated factors, transforming growth factor alpha and transforming growth factor beta. Chemical name: Animal growth regulators, transforming growth factors (12 Dec 1998) |