| agenesis | <embryology> A condition in which a part of the body (such as an organ or a tissue) does not completely develop or fails to develop at all. (09 Oct 1997) |
|---|---|
| agenesis of corpus callosum | <radiology> Defect in dorsal portion of lamina reuniens, occurs about 10th - 12th week of gestation, may be complete or partial CT findings: parallel lateral ventricles, occipital horns dilated, deep falx, frontal horns C-shaped on coronal view associated with, Dandy-Walker cyst, encephalocele, Arnold-Chiari malformation, CNS lipoma (12 Dec 1998) |
| renal agenesis | <radiology> Associated with, duplicated vagina and/or uterus (mullerian duct anomaly), seminal vesicle cysts (12 Dec 1998) |
| gonadal agenesis | Congenital absence of essentially all gonadal tissue; the external genitalia and genital ducts are female, but if interstitial cells of Leydig are present, the external genitalia are commonly ambiguous and the genital ducts are female. See: gonadal dysgenesis. Compare: Klinefelter's syndrome, Turner's syndrome. Synonym: gonadal agenesis. (05 Mar 2000) |
| sacral agenesis | <radiology> Agenesis or hypoplasia of sacrum, part of caudal-regression syndrome, associated with maternal diabetes, with or without inherited, possible features: absent lower extremities, bladder/bowel impairment (12 Dec 1998) |
| thymic agenesis | The absence of the thymus, which may be associated with parathyroid agenesis in DiGeorge syndrome. (05 Mar 2000) |
| receptors, cytoplasmic and nuclear | Proteins in the cytoplasm or nucleus that specifically bind signalling molecules and trigger changes which influence the behaviour of cells. The major groups are the steroid hormone receptors, which usually are found in the cytoplasm, and the thyroid hormone receptors, which usually are found in the nucleus. Receptors, unlike enzymes, generally do not catalyze chemical changes in their ligands. (12 Dec 1998) |
| Remak's nuclear division | <cell biology> An unusual form of nuclear division, in which the nucleus simply constricts, rather like a cell without chromosome condensation or spindle formation. Partitioning of daughter chromosomes is haphazard. Observed in some Protozoa. (18 Nov 1997) |
| Pelger-Huet nuclear anomaly | Congenital inhibition of lobulation in the nuclei of neutrophilic leukocytes; most cells present band or bilobulate appearance, and only an occasional cell is trilobed; it is not associated with disease, but may be confused with leukocyte "shift to left"; autosomal dominant inheritance. (05 Mar 2000) |
| ribonucleoproteins, small nuclear | Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm. The u3 snrnp is localised in the nucleolus, where it aligns into base pairs with the 28s rrna precursor in a still unidentified region and functions in pre-rrna processing. The u7 snrnp aligns into base pairs with a conserved sequence in the 3'-end of histone pre-mRNA and is an essential cofactor for the cleavage that creates the mature nonadenylated 3'-end. (12 Dec 1998) |
| RNA, heterogeneous nuclear | Nuclear nonribosomal RNA larger than about 1000 nucleotides, the mass of which is rapidly synthesised and degraded within the cell nucleus. Some heterogeneous nuclear RNA may be a precursor to mRNA. However, the great bulk of total hnrna hybridises with nuclear DNA rather than with mRNA. (12 Dec 1998) |
| RNA, nuclear | RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm. (12 Dec 1998) |
| RNA, small nuclear | Short chains of RNA found in the nucleus. Their function is to remove the introns (nontranslated intervening sequences) from mRNA precursors, thereby bringing the two exons (coding segments) together into correct juxtaposition for enzymatic splicing at the correct point. The resulting mRNA is now ready to leave the nucleus. (12 Dec 1998) |
| rod nuclear cell | <pathology> Immature neutrophils released from the bone marrow reserve in response to acute demand. (18 Nov 1997) |
| cistern of nuclear envelope | The space between the internal and external membranes of the nuclear envelope; may be continuous in places with cisterns of the endoplasmic reticulum. Synonym: cistern of nuclear envelope, perinuclear space. (05 Mar 2000) |