| retinal blood vessels | The blood vasculature of the retina, including the branches and tributaries of the central retinal artery and vein, respectively, and the vascular circle of the optic nerve. Synonym: vasa sanguinea retinae. (05 Mar 2000) |
|---|---|
| percutaneous umbilical blood sampling | See: PUBS. (12 Dec 1998) |
| Rhesus blood group | <haematology> Human blood group system with allelic red cell antigens C, D and E. The D antigen is the strongest. Red cells from a Rhesus positive foetus cross the placenta and can sensitise a Rehesus negative mother, expecially at parturition. The mother's antibody may then, in a subsequent pregnancy, cause haemolytic disease of the newborn if the foetus is Rhesus positive. The disease can be prevented by giving antiD IgG during the first 72 hours after parturition to mop up D red cells in the maternal circulation. 1st ed (18 Nov 1997) |
| rh-hr blood-group system | Erythrocyte isoantigens of the rh (rhesus) blood group system, the most complex of all human blood groups, because the genes differ by determining a different number of the over thirty antigens thus far described and do so with remarkably different quality. The major antigen rh or d is the most common cause of erythroblastosis foetalis. (12 Dec 1998) |
| peripheral blood stem cell transplantation | A procedure that is similar to bone marrow transplantation. Doctors remove healthy immature cells (stem cells) from a patient's blood and store them before the patient receives high-dose chemotherapy and possibly radiation therapy to destroy the leukaemia cells. The stem cells are then returned to the patient, where they can produce new blood cells to replace cells destroyed by the treatment. (12 Dec 1998) |
| Pfeiffer's blood agar | Solid agar with a few drops of human blood smeared on the surface. (05 Mar 2000) |
| Romanowsky's blood stain | <technique> Prototype of the eosin-methylene blue stain's for blood smears, using aqueous solutions made of a mixture of methylene blue (saturated) and eosin. Romanowsky-type stain's depend for their action on compounds formed by interaction of methylene blue and eosin; most are of no value if water is present in the alcohol because neutral dyes become precipitated. (05 Mar 2000) |
| MN blood group antigens | <haematology, immunology> A pair of blood group antigens governed by genes that segregate independently of the ABO locus. The alleles are codominant and there are three types MM, NN and MN. Glycophorin has M or N activity and this is associated with oligosaccharides attached to the amino terminal portion of the molecule. M type glycophorin differs from N type in amino acid residues 1 and 5, although the antigenic determinants are associated with the carbohydrate side chains. (18 Nov 1997) |
| MNSs blood group | See Blood Groups appendix. (05 Mar 2000) |
| mnss blood-group system | A system of universal human blood group isoantigens with many associated subgroups. The m and n traits are codominant and the s and s traits are probably very closely linked alleles, including the u antigen. This system is most frequently used in paternity studies. (12 Dec 1998) |
| white blood cell | <haematology> White corpuscles in the blood. They are spherical, colourless and nucleated masses involved with host defenses. Normal white blood cell counts are variable with age and sex. Normal adult range is 4, 500 to 11,000 cells per cubic millimetre of blood. Slightly higher counts are seen in children. Elevated counts can be seen in cases of inflammation and infection. See: leucocytes, basophils, coelomocytes, eosinophils, haemocytes, lymphocytes, neutrophils, monocytes. Acronym: WBC (13 Nov 1997) |
| white blood cell cast | A urinary cast composed of polymorphonuclear leukocytes, characteristic of tubulointerstitial disease, especially pyelonephritis. (05 Mar 2000) |
| white blood cell count | <haematology> A laboratory test which measures the number of white blood cells per cubic millimetre of blood. Normal white blood cell counts are variable with age and sex. Normal adult range is 4, 500 to 11,000 cells per cubic millimetre of blood. Slightly higher counts are seen in children. Elevated counts can be seen in cases of inflammation and infection. (13 Nov 1997) |
| white blood cell differential | <haematology> The white blood cell differential is a percentage of each type of white blood cell based on a count of 100 white cells. A change in the white blood cell type (to neutrophils or bands) can indicate a bacterial infection. Neutrophils, bands, lymphocytes, monocytes, basophils and eosinophils are all included. (13 Nov 1997) |
| white blood cells | White blood cells (WBCs) are cells which circulate in the blood and lymphatic system and harbor in the lymph glands and spleen. They are part of the immune system responsible for both directly (t cells and macrophages) and indirectly (B-cells producing antibodies) attacking foreign invaders of the body. (12 Dec 1998) |