| growth rate | <biology, cell culture, ecology> The rate, or speed, at which the number of organisms in a population increases. This can be calculated by dividing the change in the number of organisms from one point in time to another by the amount of time in the interval between the points of time. The phrase is most often used to describe growth of cells or microorganisms in laboratory cultures and usually expressed as the generation time. (21 Jun 2000) |
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| growth rate of population | <epidemiology> A measure of population change in the absence of migration, comprising addition of newborns and subtraction of deaths; the result is known as the natural rate of increase of the population; it is the difference between the crude birth rate and the crude death rate. (05 Mar 2000) |
| growth substance | <biology, cell biology> Signal molecules that are involved in the control of cell growth and differentiation. (12 Dec 1998) |
| chorionic growth hormone-prolactin | human placental lactogen |
| Rubner's laws of growth | The law of constant energy consumption: the rapidity of growth is proportional to the intensity of the metabolic processes, the law of the constant growth quotient: in most young mammals, 24% of the entire food energy, or calories, is utilised for growth; in humans only 5% is utilised. (05 Mar 2000) |
| pituitary growth hormone | <protein> Hormone (191 amino acids) released by anterior pituitary that stimulates release of somatomedin, thereby causing growth. (18 Nov 1997) |
| comb-growth test | A test for androgenic activity, based upon the stimulation of comb growth in capons (castrated cockerels) or immature roosters. Synonym: capon-comb-growth test, cock's comb test. (05 Mar 2000) |
| placental growth hormone | human placental lactogen |
| plant growth regulators | Any of the hormones produced naturally in plants and active in controlling growth and other functions. There are three primary classes: auxins, cytokinins, and gibberellins. (12 Dec 1998) |
| plant growth substances | <plant biology> Substances that, at low concentration, influence plant growth and differentiation. Formerly referred to as plant hormones or phytohormones, these terms are now suspect because some aspects of the hormone concept, notably action at a distance from the site of synthesis, do not necessarily apply in plants. Also called plant growth regulators. The major classes are absicisic acid, auxin, cytokinin, ethylene and gibberellin, others include steroid and phenol derivatives. (31 Dec 1997) |
| 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) |
| 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) |