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biological response modifier definition: a diversity of reagents employed for nonspecific active immunization; used to enhance the immune response; 4 major groups: bacterial products, synthetic molecules, cytokines, and hormones.
Immunomodulating Agent definition: Substances or procedures that enhance the host's ability to inhibit tumorigenesis or tumor progression or that increase the differential between tumor and host susceptibility to therapeutic agents. Thus BRMs can be preventive (vaccines, vitamins) or therapeutic (interferon, monoclonal antibodies, hyperthermia, gene therapy.) Standard, nonspecific therapies such as drugs and radiation are excluded but radiation delivered via antibodies would be included since it exploits a differential susceptibility of tumor and host.
Juvenile Hormones definition: Compounds, either natural or synthetic, which block development of the growing insect.
juvenile hormone definition: natural or synthetic compounds which prevent metamorphosis in the growing insect.
Plant Growth Regulators definition: 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.
plant growth regulator definition: any of the hormones produced naturally in plants and active in controlling growth and other functions of the plant, including auxins, cytokinins, and gibberellins.
phytohormone definition: plant hormone; any of the hormones produced naturally in plants including plant produced analogs of animal hormones; active in small amounts in controlling growth and other functions at a site remote from the place of production.
Transforming Growth Factors definition: 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 tumor-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.
transforming growth factor definition: any of several proteins secreted by transformed cells and stimulating growth of normal cells; transforming growth factor alpha binds the epidermal growth factor receptor and also stimulates growth of microvascular endothelial cells; transforming growth factor beta exists as several subtypes; all occur in hematopoietic tissue, stimulate wound healing, and in vitro are antagonists of lymphopoiesis and myelopoiesis.
Transforming Growth Factor definition: Transforming Growth Factors are a family of extracellular signaling peptides involved in cell growth stimulation. Found in hematopoietic tissue, various TGF-beta subtypes stimulate wound healing and may inhibit lymphopoiesis and myelopoiesis. TGF-alpha binds to EGFR and stimulates endothelial cell growth.
REGULATOR, PRESSURE, GAS CYLINDER definition: A pressure regulator is a device, often called a pressure-reducing valve, that is intended for medical purposes and that is used to convert a medical gas pressure from a high variable pressure to a lower, more constant working pressure. This device includes mechanical oxygen regulators.
Power Supplies, Line-Voltage Stabilization definition: Power supplies designed to deliver an almost steady, predetermined value of AC voltage (e.g., 120 V) for a limited range of input line voltage variations (e.g., plus or minus 10%). These devices typically include an electronic line voltage monitor to detect line voltage fluctuations and some electric or electronic stabilization circuit or device to compensate for these variations. Line voltage stabilizing power supplies are mostly used to maintain normal operation of electrical equipment (e.g., motors, pumps, lights, refrigerators) under reduced-voltage conditions (brownouts).
REGULATOR, VACUUM definition: A vacuum-powered body fluid suction apparatus is a device used to aspirate, remove, or sample body fluids. The device is powered by an external source of vacuum. This generic type of device includes vacuum regulators, vacuum collection bottles, suction catheters and tips, connecting flexible aspirating tubes, rigid suction tips, specimen traps, noninvasive tubing, and suction regulators (with gauge).
Regulators, Suction, Surgical definition: Suction regulators designed to control the high levels of negative pressure (usually from 400 to 600 mm Hg) applied at the surgical site; some regulators permit the application of full line suction from wall vacuum outlets. These regulators usually include the pressure-regulation mechanism, pressure-adjusting controls, and a calibrated manometer. Surgical suction regulators are usually a component of a suction system connected to the wall outlet of a central vacuum system; they are used to control the removal of secretions (e.g., vomitus, mucus, blood) during surgical procedures as well as secretions in wound cavities after surgery.
RGS Proteins definition: A large family of evolutionarily conserved proteins that function as negative regulators of HETEROTRIMERIC GTP-BINDING PROTEINS. RGS PROTEINS act by increasing the GTPase activity of the G alpha subunit of a heterotrimeric GTP-binding protein, causing it to revert to its inactive (GDP-bound) form.
RGS Family Protein definition: RGS family proteins activate GTPase and regulate G protein signaling by stimulating the inactivation of heterotrimeric G proteins. RGS family proteins are responsible for the rapid turnoff of G protein-coupled receptor signaling pathways. There are indications that a subset of RGS proteins regulate specific G protein-coupled receptor pathways.
GTP-Binding Protein Regulators definition: Proteins that regulate the signaling activity of GTP-BINDING PROTEINS. They are divided into three categories depending upon whether they stimulate GTPase activity (GTPASE-ACTIVATING PROTEINS), inhibit release of GDP; (GUANINE NUCLEOTIDE DISSOCIATION INHIBITORS); or exchange GTP for GDP; (GUANINE NUCLEOTIDE EXCHANGE FACTORS).
RGS Family Gene definition: RGS Family Genes encode evolutionarily conserved proteins containing the RGS (Regulator of G protein Signaling) domain and generally function as negative regulators of heterotrimeric G protein signaling; several promote the GTPase activity of G protein alpha-subunits, causing it to revert to its inactive (GDP-bound) form. (OMIM)
Bone Mineralization Regulation Pathway definition: Osteoblasts mineralize bone matrix by promoting hydroxyapatite crystal formation and growth in the interior of membrane-limited matrix vesicles (MVs) and by propagating the crystals onto the collagenous extracellular matrix. Two osteoblast proteins, tissue-nonspecific alkaline phosphatase (TNAP) and plasma cell membrane glycoprotein-1 (PC-1) are involved in this process. In the bone matrix, PC-1 is the major producer of PPi, which in turn has an inhibitory effect on hydroxyapatite deposition. TNAP has a positive influence on mineralization primarily by controlling the size of the inhibitory pool of PPi through its inorganic pyrophosphatase activity. TNAP also generates Pi by using NTPs and PPi as substrates, but other more major sources of Pi e.g., intestinal absorption, are likely to contribute the bulk of the Pi needed for hydroxyapatite deposition. (BioCarta)
RGS Domain definition: Typically 120 amino acids long, the RGS (Regulator of G protein Signaling) Domain is found in over 20 human proteins, bind activated G-alpha subunits, and are responsible for GAP function. Through other domains (e.g., DEP, PDZ, or PH) RGS proteins link to other signaling molecules. RGS domains contain conserved contiguous, or dispersed, GH subdomains (GH1, 2, and 3). All RGS domains share a tertiary structure of nine alpha helixes that form a right-handed anti-parallel bundle of helixes 4-7 and a terminal bundle of helixes 1-3 and 8-9. The 3-4, 5-6, and 7-8 helix loops form an interaction surface between RGS4 and Ga(i). RGS domains allosterically stabilize the G-alpha GTP binding pocket, accelerating GTPase activity. Thus, RGS Family members rapidly inactivate G protein signal transmission from seven transmembrane receptors in GPCR signaling pathways. (NCI)