| DNA sequence, unstable | DNA region comprised of a variable number of repetitive, contiguous trinucleotide sequences. Presence of these regions is associated with diseases such as fragile x syndrome and myotonia atrophica. (12 Dec 1998) |
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| sequence analysis, DNA | A multistage process that includes DNA cloning, physical mapping, subcloning, sequencing, and information analysis. New technological advances have led to the automation of certain steps in this process and contribute to the potential for large-scale DNA sequencing efforts. (12 Dec 1998) |
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| DNA sequence | <molecular biology> The relative order of base pairs, whether in a fragment of DNA, a gene, a chromosome, or an entire genome. See: base sequence analysis. (09 Oct 1997) |
| DNA sequence analysis | <molecular biology> Determination of the nucleotide sequence of a length of DNA. Typically, this is performed by cloning the DNA of interest, so that enough can be prepared to allow the sequence to be determined, usually by the Sanger dideoxy chain temination or Maxam Gilbert chain degradation techniques. The resulting reactions are then run on a large sequencing gel, capable of resolving single nucleotide differences in chain length. Recently, PCR based methods have obviated the need to clone the DNA under some conditions and automated DNA sequencing has become widely available. (18 Nov 1997) |
| angina, unstable | Precordial pain at rest, which may precede a myocardial infarction. (12 Dec 1998) |
| unstable angina | <cardiology> Angina which is new onset or prior existing angina which is increasing in severity, duration or frequency. (13 Nov 1997) |
| unstable bladder | Characterised by uninhibited detrusor contractions. (05 Mar 2000) |
| unstable cervical spine fractures | <radiology> Flexion: bilateral interfacetal dislocation, flexion teardrop fracture (usually C5 or C6) extension: extension teardrop fracture (usually C2 or C3), hangman's fracture, extension-dislocation, extension-fracture-dislocation, odontoid fracture vertical compression: Jefferson burst fracture see: cervical spine fractures (12 Dec 1998) |
| unstable colloid | A colloid that is not again soluble in water after having been dried at ordinary temperature. Synonym: unstable colloid. (05 Mar 2000) |
| unstable fracture | A fracture with an intrinsic tendency to slip out of place after reduction. (05 Mar 2000) |
| unstable haemoglobin haemolytic anaemia | A congenital haemolytic anaemia, due to autosomal inheritance of one of many unstable haemoglobins. The anaemia is of variable severity and characterised by the presence in vivo or in vitro of Heinz bodies. (05 Mar 2000) |
| unstable haemoglobins | A group of rare Hb's with amino acid substitutions (or amino acid deletions in three types) that alter the three-dimensional shape of the globin in a manner that renders the molecule unstable; they have an increased but variable tendency to auto-oxidation and Heinz body formation and are associated with congenital nonspherocytic haemolytic anaemia. The unstable b chain abnormalities include Hb's Genova, Gun Hill, Hammersmith, Koln, Philly, Sabine, Santa Ana, Sydney, Wien, and Zurich; unstable a chain abnormalities include Hb's Bibba, Sinai, and Torino. (05 Mar 2000) |
| unstable mutation | <molecular biology> A mutation that has a high likelihood of reverting to its original form. (13 Nov 1997) |
| unstable patient | The distinction of stability is made by a physician and based on a large number of variables: patient diagnosis, vital signs, physical findings, laboratory findings, subjective factors and patient prognosis. (27 Sep 1997) |
| DNA-directed DNA polymerase | <enzyme> DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair. Chemical name: Deoxynucleoside-triphosphate:DNA deoxynucleotidyltransferase (DNA-directed) Registry number: EC 2.7.7.7 (12 Dec 1998) |
| alu sequence | Any of a family of short (300 basepairs long) repeated sequences that occur throughout the human genome. (09 Oct 1997) |