Document Detail


Nonlinear analysis of renal autoregulation in rats using principal dynamic modes.
MedLine Citation:
PMID:  9916757     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This article presents results of the use of a novel methodology employing principal dynamic modes (PDM) for modeling the nonlinear dynamics of renal autoregulation in rats. The analyzed experimental data are broadband (0-0.5 Hz) blood pressure-flow data generated by pseudorandom forcing and collected in normotensive and hypertensive rats for two levels of pressure forcing (as measured by the standard deviation of the pressure fluctuation). The PDMs are computed from first-order and second-order kernel estimates obtained from the data via the Laguerre expansion technique. The results demonstrate that two PDMs suffice for obtaining a satisfactory nonlinear dynamic model of renal autoregulation under these conditions, for both normotensive and hypertensive rats. Furthermore, the two PDMs appear to correspond to the two main autoregulatory mechanisms: the first to the myogenic and the second to the tubuloglomerular feedback (TGF) mechanism. This allows the study of the separate contributions of the two mechanisms to the autoregulatory response dynamics, as well as the effects of the level of pressure forcing and hypertension on the two distinct autoregulatory mechanisms. It is shown that the myogenic mechanism has a larger contribution and is affected only slightly, while the TGF mechanism is affected considerably by increasing pressure forcing or hypertension (the emergence of a second resonant peak and the decreased relative contribution to the response flow signal).
Authors:
V Z Marmarelis; K H Chon; N H Holstein-Rathlou; D J Marsh
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Annals of biomedical engineering     Volume:  27     ISSN:  0090-6964     ISO Abbreviation:  Ann Biomed Eng     Publication Date:    1999 Jan-Feb
Date Detail:
Created Date:  1999-04-07     Completed Date:  1999-04-07     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0361512     Medline TA:  Ann Biomed Eng     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  23-31     Citation Subset:  IM    
Affiliation:
Department of Biomedical Engineering, University of Southern California, Los Angeles 90089-1451, USA. vzm@bmsrs.usc.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Homeostasis / physiology*
Kidney / physiology*
Male
Models, Biological*
Rats
Rats, Sprague-Dawley
Grant Support
ID/Acronym/Agency:
DR-15968//PHS HHS; HL-45623/HL/NHLBI NIH HHS; RR-01861/RR/NCRR NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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