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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Daily rhythm of cerebral blood flow velocity. | Journal of Circadian Rhythms BioMed Central Research Daily rhythm of cerebral blood flow velocity Deirdre A Conroy 1 Arthur J Spielman1 2 and Rebecca Q Scott3 Open Access Address department of Psychology The Graduate School and University Center of the City University of New York New York USA department of Neurology and Neuroscience New York Presbyterian Hospital New York USA and department of Health Psychology Albert Einstein Medical College at Yeshiva University Bronx USA Email Deirdre A Conroy - deirdre.conroy@att.net Arthur J Spielman - thrilla834@aol.com Rebecca Q Scott - beckyqscott@yahoo.com Corresponding author Published 10 March 2005 Received 21 December 2004 Accepted 10 March 2005 Journal of Circadian Rhythms 2005 3 3 doi 10.1186 1740-3391-3-3 This article is available from http www.jcircadianrhythms.cOm content 3 1 3 2005 Conroy et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http creativecommons.Org licenses by 2.0 which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background CBFV cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler TCD ultrasonography. Other variables included core body temperature CBT end-tidal carbon dioxide EtCO2 blood pressure and heart rate. Salivary dim light melatonin onset DLMO served
