| primary spermatocyte | <cell biology> A stage in the differentiation of the male germ cells. Spermatogonia differentiate into primary spermatocytes, showing a considerable increase in size in doing so, primary spermatocytes divide into secondary spermatocytes. (18 Nov 1997) |
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| primary structure | The covalent backbone of a macromolecule. The order of subunits in a biological polymer, such as amino acids in a polypeptide or nucleotides in a molecule of DNA or RNA. (09 Oct 1997) |
| primary syphilis | The first stage of syphilis See: syphilis. (05 Mar 2000) |
| primary teeth | <dentistry> The first set of teeth that develop in childhood. Synonym: deciduous teeth. (08 Jan 1998) |
| primary telangiectasia | angioma serpiginosum |
| primary tooth | A tooth of the first set of teeth, comprising 20 in all, that erupts between the mean ages of 6 and 28 months of life. Synonym: dens deciduus, baby tooth, deciduous dentition, dens lacteus, first dentition, milk tooth, primary dentition, primary tooth, temporary tooth. (05 Mar 2000) |
| primary transcript | <molecular biology> RNA transcript immediately after transcription in the nucleus, before RNA splicing or polyadenylation to form the mature mRNA. (18 Nov 1997) |
| primary tuberculosis | First infection by Mycobacterium tuberculosis, typically seen in children but also occurs in adults, characterised in the lungs by the formation of a primary complex consisting of small peripheral pulmonary focus with spread to hilar or paratracheal lymph nodes; may cavitate or heal with scarring or may progress. Synonym: childhood type tuberculosis. (05 Mar 2000) |
| primary tumour | <oncology> The mass of tumour cells at the original site of the neoplastic event from the primary tumour metastasis will lead to the establishment of secondary tumours. (18 Nov 1997) |
| primary union | Healing by fibrous adhesion, without suppuration or granulation tissue formation. Synonym: primary adhesion, primary union. (05 Mar 2000) |
| primary uterine inertia | True uterine inertia, uterine inertia that occurs when the uterus fails to contract with sufficient force to effect continuous dilation or effacement of the cervix or descent or rotation of the foetal head, and when the uterus is easily indentable at the acme of contraction, secondary uterine inertia, uterine inertia that occurs when the uterine contractions are vigorous but, as a result of the exhaustion or dehydration of the patient, decrease in vigor, and the progress of labour ceases. (05 Mar 2000) |
| primary vaccination | <virology> First or principal vaccination with the introduction of a vaccine into the body for the purpose of inducing immunity. (18 Nov 1997) |
| primary villus | The first stage of chorionic villus development, with columns of cytotrophoblastic cells covered by syncytiotrophoblast. (05 Mar 2000) |
| primary visual area | Area of the occipital lobe concerned with vision. (12 Dec 1998) |
| primary visual cortex | See: visual cortex. (05 Mar 2000) |