| double helix | <molecular biology> Conformation or shape that two linear strands of DNA assume when bonded together and become twisted into a helix. (10 Nov 1998) |
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| double hemiplegia | Paralysis of corresponding parts on both sides of the body. Synonym: double hemiplegia. Origin: G. Di-, two, + plege, a stroke (05 Mar 2000) |
| double immunodiffusion | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| double inlet atrioventricular connections | Connections in which both atrial chambers connect to the same ventricle. (05 Mar 2000) |
| double intussusception | <gastroenterology, surgery> A second intussusception that involves the bowel above the first; the first intussusception is followed by contraction of the bowel wall around it, and the solid mass so formed is enveloped by the proximal portion of the bowel and is thus the cause of the second intussusception. (05 Mar 2000) |
| double layer | <physiology> The zone adjacent to a charged particle in which the potential falls effectively to zero. An excess or deficiency of electrons on the surface (charge, not to be confused with the transmembrane potential) leads to an equivalent excess of ions of the opposite charge in the surrounding fluid. For most cells, that have negative charges, there will be an excess of cations immediately adjacent to the plasma membrane and at physiological ionic strength the double layer is likely to be around 2-3 nm thick. (10 Oct 1997) |
| double lip | Congenital or acquired excess tissue on the inner mucosal aspect of the lip; may be a manifestation of Ascher's syndrome. (05 Mar 2000) |
| double loop hernia | The presence of two loops of intestine in a hernial sac. Synonym: double loop hernia. (05 Mar 2000) |
| double-masked experiment | A double-blind study conducted so neither the subject nor the observer know the identity of the control or variable. (05 Mar 2000) |
| double membrane | <cell biology> Two biomembrane layers, with an intermembranal space, surrounding certain organelles (e.g., mitochondria) or structures. (05 Mar 2000) |
| double minute | <molecular biology> Small pieces of a chromosome containing many copies of the same gene. (09 Oct 1997) |
| double minute chromosomes | <genetics, molecular biology> Paired, extrachromosomal elements lacking centromeres, often associated with a drug resistance gene. (05 Mar 2000) |
| double-mouthed uterus | Septate uterus in which the cervix is divided into two by a septum. Synonym: double-mouthed uterus, uterus biforis. (05 Mar 2000) |
| double outlet right ventricle | <cardiology, embryology> Incomplete transposition of the great vessels in which both the aorta and the pulmonary artery arise from the right ventricle, often associated with a subaortic ventricular septal defect. (12 Dec 1998) |
| double pedicle flap | A flap with two pedicles, one at each end. Synonym: double pedicle flap. (05 Mar 2000) |