| sign | <clinical sign> An objective physical finding found by the examiner. (27 Sep 1997) |
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| sign blindness | Visual agnosia for signs. (05 Mar 2000) |
| sign language | A system of hand gestures used for communication by the deaf or by people speaking different languages. (12 Dec 1998) |
| sign of elongation | <microscopy> Referring to the elongation of a substance in relation to refractive indices. If it is elongated in the direction of the high refractive index, it is said to have a positive sign of elongation. If it is elongated in the direction of the low refractive index, it has a negative sign of elongation, not to be confused with the sign of double refraction (i.e., optic sign). (05 Aug 1998) |
| sign of the orbicularis | In hemiplegia, inability to voluntarily close the eye on the paralysed side except in conjunction with closure of the other eye. Synonym: Revilliod's sign. (05 Mar 2000) |
| signal | 1. Noticeable; distinguished from what is ordinary; eminent; remarkable; memorable; as, a signal exploit; a signal service; a signal act of benevolence. "As signal now in low, dejected state As erst in highest, behold him where he lies." (Milton) 2. Of or pertaining to signals, or the use of signals in conveying information; as, a signal flag or officer. The signal service, a bureau of the government (in the United States connected with the War Department) organised to collect from the whole country simultaneous raports of local meteorological conditions, upon comparison of which at the central office, predictions concerning the weather are telegraphed to various sections, where they are made known by signals publicly displayed. Signal station, the place where a signal is displayed; specifically, an observation office of the signal service. Synonym: Eminent, remarkable, memorable, extraordinary, notable, conspicuous. Origin: From signal, n., cf. F. Signale. Source: Websters Dictionary (01 Mar 1998) |
| signal detection (psychology) | A theory of psychophysics which characterises not only the acuity of an individual's discrimination but also the psychological factors that bias his judgment. (12 Dec 1998) |
| signal node | A firm supraclavicular lymph node, especially on the left side, sufficiently enlarged that it is palpable from the cutaneous surface; such a lymph node is so termed because it may be the first recognised presumptive evidence of a malignant neoplasm in one of the viscera. A signal node that is known to contain a metastasis from a malignant neoplasm is sometimes designated by an old eponym, Troisier's ganglion. Synonym: jugular gland, Virchow's node. (05 Mar 2000) |
| signal peptidase | A peptide present on proteins that are destined either to be secreted or to be membrane components. It is usually at the N terminus and normally absent from the mature protein. Normally refers to the sequence (ca 20 amino acids) that interacts with signal recognition particle and directs the ribosome to the endoplasmic reticulum where co translational insertion takes place. Could also refer to sequences that direct post translational uptake by organelles. Signal peptides are highly hydrophobic but with some positively charged residues. The signal sequence is normally removed from the growing peptide chain by signal peptidase, a specific protease located on the cisternal face of the endoplasmic reticulum. See: signal recognition particle. (18 Nov 1997) |
| signal peptidase complex | A peptide present on proteins that are destined either to be secreted or to be membrane components. It is usually at the N terminus and normally absent from the mature protein. Normally refers to the sequence (ca 20 amino acids) that interacts with signal recognition particle and directs the ribosome to the endoplasmic reticulum where co translational insertion takes place. Could also refer to sequences that direct post translational uptake by organelles. Signal peptides are highly hydrophobic but with some positively charged residues. The signal sequence is normally removed from the growing peptide chain by signal peptidase, a specific protease located on the cisternal face of the endoplasmic reticulum. See: signal recognition particle. (18 Nov 1997) |
| signal peptide | A peptide present on proteins that are destined either to be secreted or to be membrane components. It is usually at the N terminus and normally absent from the mature protein. Normally refers to the sequence (ca 20 amino acids) that interacts with signal recognition particle and directs the ribosome to the endoplasmic reticulum where co translational insertion takes place. Could also refer to sequences that direct post translational uptake by organelles. Signal peptides are highly hydrophobic but with some positively charged residues. The signal sequence is normally removed from the growing peptide chain by signal peptidase, a specific protease located on the cisternal face of the endoplasmic reticulum. See: signal recognition particle. (18 Nov 1997) |
| signal peptide p25-subunit IV cytochrome oxidase | <chemical> Similar in action to melittin Synonym: p25 presequence peptide-cytochrome oxidase, pre-ctox p25 (26 Jun 1999) |
| signal peptides | Additional polypeptide sequence of 25 to 30 residues at the amino-terminal or carboxy-terminal end of proteins. The signal sequence signals the cellular fate or destination of a newly synthesised protein directing it to its ultimate destination in the cell. These leaders are recognised by the signal recognition particle and bound by specific receptor sites on the outer surface of the endoplasmic reticulum. They are then transported into the cisterna of the endoplasmic reticulum and from there directed to their ultimate destination in the cell. In prokaryotes, the signal peptides attach to the plasma membrane. These signal sequences are ultimately removed by specific peptidases. (12 Dec 1998) |
| signal processing, computer-assisted | Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity. (12 Dec 1998) |
| signal recognition particle | A complex between a 7S RNA and six proteins. SRP binds to the nascent polypeptide chain of eukaryotic proteins with a signal sequence and halts further translation until the ribosome becomes associated with the rough endoplasmic reticulum. One of the SRP proteins (srp54) binds GTP and in association with 7SRNA and srp19 has GTPase activity. (18 Nov 1997) |
| Aaron's sign | <clinical sign> In acute appendicitis, a referred pain or feeling of distress in the epigastrium or precordial region on continuous firm pressure over McBurney's point. (05 Mar 2000) |
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| Abadie's sign of tabes dorsalis | Insensibility to pressure over the tendo achillis. (05 Mar 2000) |
| Abrahams' sign | <clinical sign> An obsolete sign: Rales and other adventitious sounds, changes in the respiratory murmurs, and increase in the whispered sound can be heard on auscultation over the acromial end of the clavicle some time before they become audible at the apex; heard primarily in pulmonary tuberculosis affecting the apical portion of the lung, a dull-flat note, i.e., one between the normal dullness at the right apex and absolute flatness, heard on percussion in that region, indicating progress from incipient to advanced tuberculosis. (05 Mar 2000) |
| accessory sign | <clinical sign> A finding frequently but not consistently present in a disease. Synonym: assident sign. (05 Mar 2000) |
| Allis' sign | <clinical sign> In fracture of the neck of the femur, the trochanter rides up, relaxing the fascia lata, so that the finger can be sunk deeply between the great trochanter and the iliac crest. (05 Mar 2000) |
| Amoss' sign | <clinical sign> In painful flexion of the spine, it is necessary to support a sitting position by extending the arms behind the torso with the weight placed on the hands. (05 Mar 2000) |
| Anghelescu's sign | <clinical sign> In vertebral tuberculosis, painful or impossible flexion of the spine when the patient attempts to rest weight on the heels and occiput. (05 Mar 2000) |
| antecedent sign | <clinical sign> A sign that appears during the prodrome of a disease. Synonym: antecedent sign. (05 Mar 2000) |
| assident sign | <clinical sign> A finding frequently but not consistently present in a disease. Synonym: assident sign. (05 Mar 2000) |
| Auenbrugger's sign | <clinical sign> An epigastric prominence seen in cases of marked pericardial effusion. (05 Mar 2000) |
| Aufrecht's sign | <clinical sign> An obsolete sign: diminished breath sounds in the trachea just above the jugular notch, in cases of stenosis. (05 Mar 2000) |
| B6 bronchus sign | In lung radiology, appearance of an air bronchogram of the superior segmental bronchus of the lower lobe because of segmental atelectasis or consolidation. (05 Mar 2000) |
| Babinski's sign | <clinical sign> Extension of the great toe and abduction of the other toes instead of the normal flexion reflex to plantar stimulation, considered indicative of pyramidal tract involvement ("positive" Babinski). Synonym: Babinski reflex, Babinski's phenomenon, great-toe reflex, paradoxical extensor reflex, toe phenomenon. (05 Mar 2000) |
| Baccelli's sign | <clinical sign> An obsolete sign: good conduction of the whisper in nonpurulent pleural effusions. Synonym: aphonic pectoriloquy. (05 Mar 2000) |
| Ballance's sign | <clinical sign> The presence of a dull percussion note in both flanks, constant on the left side but shifting with change of position on the right, said to indicate ruptured spleen; the dullness is due to the presence of blood, fluid on the right side but coagulated on the left. (05 Mar 2000) |