| FTH | ferritin heavy chain; fracture threshold |
|---|---|
| Gm | an allotype marker on the heavy chains of immunoglobins |
| HC | hair cell; hairy cell; handicapped; head circumference; head compression; health care; healthy contr... |
| HCD | health care delivery; heavy-chain disease; high-calorie diet; high-carbohydrate diet; homologous can... |
| HMM | heavy meromyosin; hexamethyl-melamine |
| heavy oxygen | A stable oxygen isotope making up 0.20% of natural oxygen; used in mass spectrometry and in NMR studies of tissue. Synonym: heavy oxygen. (05 Mar 2000) |
|---|---|
| heavy spar | <chemical> Native barium sulphate or barite, so called because of its high specific gravity as compared with other non-metallic minerals. Source: Websters Dictionary (01 Mar 1998) |
| heavy water | most commonly used by cell biologists to stabilise microtubules. (18 Nov 1997) |
| immunoglobulins, heavy-chain | Major components of immunoglobulin molecules. They are the larger of the two types of polypeptide chains responsible for the biological and immunological properties of the different immunoglobulins. They differ according to the class of ig from which they were isolated, contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kD. One ig molecule comprises two heavy and two light chains. (12 Dec 1998) |
| alpha particle | <physics> A radioactive particle made up of two protons and two neutrons, these particles are created by the decay of a radioactive material or by nuclear bombardment, and they are the same as the nucleus of a helium-4 atom. (09 Oct 1997) |
| beta particle | <physics, radiobiology> An electron or positron emitted from a radioactive nucleus during beta decay. (09 Oct 1997) |
| genes, intracisternal a-particle | A family of retrovirus-like genetic elements coding for virus-like particles found regularly in early rodent embryos (2-cell to blastocyst stage), but which, under certain circumstances such as DNA hypomethylation, are transcribed in a wide variety of neoplasms, including plasmacytomas, neuroblastomas, rhabdomyosarcomas, teratocarcinomas, and colon carcinomas. (12 Dec 1998) |
| particle | <chemistry> A tiny mass of material. Origin: L. Particula, dim. Of pars = part (18 Nov 1997) |
| particle accelerators | Devices which accelerate electrically charged atomic or subatomic particles, such as electrons, protons or ions, to high velocities so they have high kinetic energy. (12 Dec 1998) |
| particle fluence | <chemistry, radiobiology> at a given point in space, the sum of energies, the number of particles or photons incident during a given time interval on a small sphere centreed at that point, divided by the cross-sectional area of that sphere. It is identical with the time integral of the particle flux density. (16 Dec 1997) |
| core particle | The group of eight histones (protein molecules which act like spools for DNA to wrap around so that it can be compacted to fit within the nucleus) in the middle of a nucleosome (which is the histone core particle plus the small segment of DNA wrapped around it). (09 Oct 1997) |
| proteinaceous infectious particle | A proposed pathogen composedonly of protein with no detectable nucleic acid and which is responsible for Creutzfeldt-Jakob disease and kuru inhumans and scrapie in sheep. (09 Oct 1997) |
| high energy particle generating unit | A machine capable of providing highly energised radiation for the purposes of radiotherapy treatment. (16 Dec 1997) |
| signal recognition particle | A complex between a 7S RNA and six proteins. SRP binds to the nascent polypeptide chain of eukaryotic proteins with a signal sequence and halts further translation until the ribosome becomes associated with the rough endoplasmic reticulum. One of the SRP proteins (srp54) binds GTP and in association with 7SRNA and srp19 has GTPase activity. (18 Nov 1997) |
| signal recognition particle receptor | Receptor for the signal recognition particle (SRP) found in the membrane of the endoplasmic reticulum. Also called docking protein. Heterodimeric, both protomers having GTP binding capacity, though dissimilar binding sites. Not until the complex of SRP, ribosome, message and nascent polypeptide chain binds to the SRP receptor is the block to further chain elongation released and concurrently the SRP is released, leaving the ribosome attached to the endoplasmic reticulum membrane. Cotranslational transport of the polypeptide delivers it into the lumen of the ER. (18 Nov 1997) |