title: Platelet aggregability in sleep-related stroke.
abstract: We examined platelet aggregability during nocturnal sleep and daytime wakefulness in patients with a history of sleep-related stroke onset (SOS) and compared it to that of matched awake-onset stroke (AOS) patients and controls without evidence of vascular disease. Aggregability was evaluated in-vitro at least seven weeks following stroke onset. Platelets were more aggregable to ADP, collagen and arachidonic acid (AA) during both sleep and wakefulness in patients with AOS (p less than 0.01). No significant difference in the mean aggregation thresholds during sleeping or waking periods were found between SOS and control groups. However, platelets were significantly more responsive to AA during sleep than during wakefulness in the SOS patients (p less than 0.01). This difference was confined to the subgroup of SOS patients who had experienced nocturnal as opposed to daytime sleep-related stroke onset, suggesting that the observed difference in platelet responsiveness to AA may be related to a circadian fluctuation in platelet aggregability rather than to a sleep-related fluctuation. Significant sleep-related changes in platelet aggregability were not identified in the other two groups.
authors.affiliation: Department of Neurology, University of the Witwatersrand.
authors.forename: C L
authors.initials: CL
authors.lastname: Voll
authors.forename: N
authors.initials: N
authors.lastname: Chetty
authors.forename: P
authors.initials: P
authors.lastname: Atkinson
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D002561:Cerebrovascular Disorders / Q000097:blood* / Q000503:physiopathology; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology
chemical_list: D001095:Arachidonic Acids; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine