| primary constriction | The narrowing between the two arms of the chromosome represented by the centromere. (05 Mar 2000) |
|---|---|
| primary dental lamina | dental ledge |
| primary dentin | Dentin which forms until the root is completed. (05 Mar 2000) |
| primary dentition | The set of 20 first (deciduous) teeth. The primary dentition is as opposed to the secondary (permanent) dentition. at birth, both sets of dentition are evident by X-ray. (12 Dec 1998) |
| primary deviation | The ocular deviation seen in paralysis of an ocular muscle when the nonparalysed eye is used for fixation. (05 Mar 2000) |
| primary digestion | Digestion in the alimentary tract. (05 Mar 2000) |
| primary disease | A disease that arises spontaneously and is not associated with or caused by a previous disease, injury, or event, but which may lead to a secondary disease. (05 Mar 2000) |
| primary dried yeast | A source of dried yeast; obtained from suitable strains of Saccharomyces cerevisiae grown in media other than those required for the production of beer. (05 Mar 2000) |
| primary drives | Those drives such as hunger and thirst which stem from the biological needs of an organism. Synonym: primary drives. (05 Mar 2000) |
| primary dysmenorrhoea | <gynaecology> Painful menses due to a functional disturbance and not due to organic factors such as growths, inflammation or anatomy. (06 Mar 1998) |
| primary egg membrane | See: egg membrane. (05 Mar 2000) |
| primary embryonic cell | In a very young embryo, a cell still capable of differentiation. (05 Mar 2000) |
| primary energy | <radiobiology> Energy before conversion. For instance, the United States uses about 30,000 megajoules of electricity per capita per year, but electricity is generally obtained by converting other forms of energy (primarily chemical/heat) at an efficiency of around 30%, so the U.S. Consumes 90,000 megajoules of primary energy per capita for electrical use. (Total U.S. Primary energy consumption is 300,000 megajoules per capita.) (09 Oct 1997) |
| primary erythroblastic anaemia | The dire disease also known as beta thalassaemia. The clinical picture of this form of anaemia was first described in 1925 by the paediatrician thomas benton cooley. Other names for the disease are cooley's anaemia and mediterranean anaemia. The term thalassaemia was coined by the nobel prise winning pathologist george whipple and the professor of paediatrics william bradford at u. Of rochester because thalassa in greek means the sea (like the mediterrranean sea) + -aemia means in the blood so thalassaemia means sea in the blood. Thalassaemia is not just one disease. It is a complex contingent of genetic (inherited) disorders all of which involve underproduction of haemoglobin, the indispensable molecule in red blood cells that carries oxygen. The globin part of normal adult haemoglobin is made up of 2 alpha and 2 beta polypeptide chains. In beta thalassaemia, there is a mutation (change) in both beta globin chains leading to underproduction (or absence) of beta chains, underproduction of haemoglobin, and profound anaemia. The gene for beta thalassaemia is relatively frequent in people of mediterranean origin (for example, from italy and greece). Children with this disease inherit one gene for it from each parent (and so are said to be homozygous for beta thalassaemia). The parents are carriers (heterozygotes) with just one thalassaemia gene, are said to have thalassaemia minor, and are essentially normal. Their children affected with beta thalassaemia seem entirely normal at birth (because at birth we still have predominantly foetal haemoglobin which does not contain beta chains) but the anaemia emerges in the first few months of life and becomes progressively more severe leading to pallor and easy fatiguability, failure to thrive (grow), bouts of fever (due to infections) and diarrhoea. Treatment based on blood transfusions is helpful but not curative. Gene therapy will, it is hoped, be applicable to this disease. (12 Dec 1998) |
| primary extrapulmonary coccidioidomycosis | A rare form of coccidioidomycosis presenting near the site of local trauma with painless firm nodules occurring at one to two weeks, accompanied by regional adenopathy, with spontaneous healing in a few weeks. (05 Mar 2000) |