| carotenoids | Generic term for a class of carotenes and their oxygenated derivatives (xanthophylls) consisting of 8 isoprenoid units joined so that the orientation of these units is reversed at the centre, placing the two central methyl groups in a 1,6 relationship in contrast to the 1,5 of the others. All carotenoids may be formally derived from the acyclic C40H56 structure (part IA, known as lycopene, of the accompanying group of structures) with its long central chain of conjugated double bonds by hydrogenation, dehydrogenation, oxidation, cyclization, or combinations of these. Included as carotenoids are some compounds arising from certain rearrangements or degradations of the carbon skeleton (structure IB), but not retinol and related C20 compounds. The nine-carbon end-groups may be acyclic with 1,2 and 5,6 double bonds (as in structure IA) or cyclohexanes with a single double bond at 5,6 or 5,4, or cyclopentanes or aryl groups; these are now designated by Greek letter prefixes (illustrated in part II of the accompanying group of structures) preceding "carotene" (a and d, which are used in the trivial names alpha-carotene and d-carotene, are not used for that reason). Suffixes (-oic acid, -oate, -al, -one, -ol) indicate certain oxygen-containing groups (acid, ester, aldehyde, ketone, alcohol); all other substitutions appear as prefixes (alkoxy-, epoxy-, hydro-, etc.). The configuration about all double bonds is trans unless cis and locant numbers appear. The prefix retro-is used to indicate a shift of one position of all single and double bonds; apo-indicates shortening of the molecule. Many carotenoids have anticancer activities. (05 Mar 2000) |
|---|---|
| carotenoprotein | A protein with a covalently-bound carotenoid. (05 Mar 2000) |
| carotenosis cutis | A harmless reversible yellow colouration of the skin caused by an increase in carotene content. Synonym: carotenoderma, carotinosis cutis. (05 Mar 2000) |
| carotic | Synonym: stuporous. Origin: G. Karotikos, stupefying (05 Mar 2000) |
| caroticoclinoid ligament | <anatomy> The ligament that connects the anterior to the middle clinoid process of the sphenoid bone. (05 Mar 2000) |
| caroticotympanic | Relating to the carotid canal and the tympanum. (05 Mar 2000) |
| caroticotympanic arteries | Small branches from the petrous part of the internal carotid artery supplying the tympanic cavity; anastomose with the anterior tympanic and maxillary arteries. Synonym: arteriae caroticotympanicae arteriae carotidis internae, rami caroticotympanici. (05 Mar 2000) |
| caroticotympanic canaliculi | Small openings within the carotid canal that afford passage to the tympanic cavity of branches of the internal carotid artery and carotid sympathetic plexus. Synonym: canaliculi caroticotympanici. (05 Mar 2000) |
| caroticotympanic nerve | <anatomy, nerve> One of two sympathetic branches from the internal carotid plexus to the tympanic plexus. Synonym: nervus caroticotympanicus, small deep petrosal nerve. (05 Mar 2000) |
| carotid | Pertaining to the carotid artery. (12 Dec 1998) |
| carotid arteries | <anatomy> Paired large calibre vessels that pass on either side of the neck supplying oxygenated blood to the brain. Occlusive disease (atherosclerosis) of the vessels can lead to stroke. (27 Sep 1997) |
| carotid artery | <anatomy, artery> A key artery located in the front of the neck that carries blood from the heart to the brain. Cholesterol plaques on the inner wall of the carotid artery can lead to stroke. (12 Dec 1998) |
| carotid artery bruit | <radiology> Differential diagnosis: Atherosclerotic plaque or stenosis in common carotid artery or major vessels., Normal vessel. Asymptomatic bruits are a risk factor for stroke, and 75% of strokes occur in the carotid circulation. The majority of patients with bruits will have stenosis of 50% or more. The vast majority (90%) of strokes occur without prior symptoms. REF: MacNeil BJ, Abrams HL. Brigham and Women's Hospital Handbook of Diagnostic Imaging. Chapter 27. (12 Dec 1998) |
| carotid artery occlusive syndrome | <syndrome> Aortic arch syndrome, also referred to by many as vertebral-basilar artery disease, carotid artery occlusive syndrome and subclavian steal syndrome. Characterised by a constellation of signs and symptoms which occur secondary to abnormalities in the major arteries which extend off of the aortic arch. These abnormalities are structural and most often secondary to the effects of atherosclerosis, blood clots, trauma or a congenital abnormality. Symptoms of this condition include various neurologic symptoms, reduction in pulse and changes in blood pressure. (27 Sep 1997) |
| carotid artery thrombosis | Formation of a clot in a carotid artery often resulting from atherosclerosis. Patients are at high risk for developing stroke. (12 Dec 1998) |