| reading-frameshift mutation | <molecular biology> A type of mutation that results from insertion or deletion of a single nucleotide into, or from, an open reading frame in the normal DNA sequence. Normally, the genetic code is read in the wrong frame, three nucleotides at a time, and the entire sequence downstream of the mutation, is translated into a polypeptide with a garbled amino acid sequence from the mutated codon onwards. These mutations may be induced by certain types of mutagens or may occur spontaneously and usually result in the generation, downstream, of nonsense, chain termination codons. Synonym: addition mutation, addition-deletion mutation, deletion mutation, reading-frameshift mutation. (21 Jun 2000) |
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| frameshift | <molecular biology> A shift in the reading frame used to translate the base sequence of DNA or mRNA. It is caused by the addition or deletion of one or more of the bases, resulting in an alternative peptide being formed. (17 Dec 1997) |
| frameshift mutagen | <molecular biology> A mutagen, such as an acridine derivative, that causes a frameshift mutation; codons (base triplets) are read out of phase and different amino acids are made. (05 Mar 2000) |
| frameshift mutation | <molecular biology> A type of mutation that results from insertion or deletion of a single nucleotide into, or from, an open reading frame in the normal DNA sequence. Normally, the genetic code is read in the wrong frame, three nucleotides at a time, and the entire sequence downstream of the mutation, is translated into a polypeptide with a garbled amino acid sequence from the mutated codon onwards. These mutations may be induced by certain types of mutagens or may occur spontaneously and usually result in the generation, downstream, of nonsense, chain termination codons. Synonym: addition mutation, addition-deletion mutation, deletion mutation, reading-frameshift mutation. (21 Jun 2000) |
| ACTH suppression test | <investigation> A test that measures the response of the adrenal glands to ACTH. In this case, dexamethasone is given to the patient and then blood cortisol levels are measured. Under normal conditions, cortisol levels should drop in response to dexamethasone. In this test one milligram of dexamethasone is administered in the morning and then the blood is drawn for analysis the following morning. Abnormal test results can indicate Cushing's syndrome. (27 Sep 1997) |
| bone marrow suppression | <oncology, pharmacology> A side effect of many anticancer and antiviral drugs, including AZT. Bone marrow suppression leads to a decrease in white blood cells, red blood cells and platelets. Such reductions in turn result in anaemia, bacterial infections and spontaneous or excess bleeding. (09 Oct 1997) |
| growth hormone suppression test | <investigation> A test to determine if growth hormone is suppressed by hyperglycaemia. Growth hormone blood levels are determined sequentially after ingestion of a glucose-rich meal. If growth hormone levels remain elevated (after the glucose is given) then acromegaly or gigantism is suspected. (27 Sep 1997) |
| cortisol suppression test | <investigation> A test that measures the response of the adrenal glands to ACTH. In this case, dexamethasone is given to the patient and then blood cortisol levels are measured. Under normal conditions, cortisol levels should drop in response to dexamethasone. In this test one milligram of dexamethasone is administered in the morning and then the blood is drawn for analysis the following morning. Abnormal test results can indicate Cushing's syndrome. (27 Sep 1997) |
| nonsense suppression | Mutant tRNAs that read a chain termination codon as the signal for incorporation of a specific amino acid residue. (05 Mar 2000) |
| suppression | 1. The act of suppressing, or the state of being suppressed; repression; as, the suppression of a riot, insurrection, or tumult; the suppression of truth, of reports, of evidence, and the like. 2. <medicine> Complete stoppage of a natural secretion or excretion; as, suppression of urine; used in contradiction to retention, which signifies that the secretion or excretion is retained without expulsion. 3. Omission; as, the suppression of a word. Synonym: Overthrow, destruction, concealment, repression, detention, retention, obstruction. Origin: L. Suppressio: cf. F. Suppression. Source: Websters Dictionary (01 Mar 1998) |
| suppression amblyopia | The suppression of the central vision in one eye when the images from the two eyes are so different that they cannot be fused into one. This may be due to: 1) faulty image formation (sensory amblyopia); 2) a large difference in refraction between the two eyes (anisometropic amblyopia); or 3) the two eyes pointing in different directions (strabismic amblyopia). Most suppression amblyopia can be reversed if appropriately treated before age 6 years. Synonym: amblyopia ex anopsia. (05 Mar 2000) |
| suppression, genetic | The restoration of the wild-type phenotype in an organism possessing a mutationally altered genotype. The effects of the mutation may be suppressed by a second "suppressor" mutation on a different gene, by a suppressor mutation on the same gene but located at a distance from the site of the primary mutation, or by the presence of a cytoplasmic suppressor due to a change in non-chromosomal DNA. (12 Dec 1998) |
| dexamethasone suppression test | <endocrinology, investigation> A test that measures the response of the adrenal glands to ACTH. Dexamethasone is given to the patient and then blood cortisol levels are measured. Under normal conditions, cortisol levels should drop in response to dexamethasone. In this test one milligram of dexamethasone is administered in the morning and then the blood is drawn for analysis the following morning. Abnormal test results can indicate Cushing's syndrome. (27 Sep 1997) |
| immune suppression | Suppression of the immune response by some compound or agent. (05 Mar 2000) |
| intergenic suppression | The situation where a primary gene and the gene that suppresses it do not lie in the same chromosomal locus. Compare: intragenic suppression. (18 Nov 1997) |