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  • Welcome Dr. Yambe's Home Page!! (eng) - [Atherosclerosis, Cardiology, Artificial heart][### [[Sympathetic nervous system|Sympathetic nerve discharges during artificial heart circulation]]]
  • 論文・出版リスト - 山家先生分 - [# Yambe T, Nitta S, Katahira Y, Sonobe T, Naganuma S, Akiho H, Hayashi H, Tanaka M, Miura M, Sato N, Mohri H, Yoshizawa M, and Takeda H: The prospective control of a total artificial heart using sympathetic tone and hemodynamic parameters. In: T.Akutsu & H.Koyanagi eds, Artificial Heart 3. Tokyo: Springer-Verlag, 1991: 189-195.][# Yambe T, Nitta S, Katahira Y, Sonobe T, Naganuma S, Y.KakinumTanaka A M, Fukuju T, Miura M, Mohri H, Yoshizawa M, Koide S, Takeda H, H.Hiyama, M.Aoki, T.Kasai, and Hashioto H: Systemic circulation with high frequency blood flow--analysis from neurophysiological point of view. Sci Rep Res Inst Tohoku Univ [Med]. 38(2-4):69-73. 1991]
  • Origin of Chaos - [The clinical significance of the chaotic dynamics in the cardiovascular system had attracted attention. Circulation system is a kind of "complex system" having many feedback circuits. So, it was very difficult to investigate the origin of chaos in the circulatory system. In this study, we investigated the origin of chaos by the use of the methodology of the open loop analysis with an artificial heart, which did not have any fluctuation in their own pumping rate and contraction power, in the chronic animal experiments using healthy adult goats. As a result, in the circulatory time series data of the artificial heart, which did not have any fluctuation, low dimensional deterministic chaos was discovered by the methodology of nonlinear mathematical analyzing technique, suggesting the importance of the blood vessel system in the chaotic dynamics of the cardiovascular system. To investigate the origin of chaos furthermore, sympathetic nerve activity was directly measured in the animal experiments with artificial heart circulation. Chaotic dynamics was also recognized in the sympathetic nerve action potentials, even during artificial heart circulation, suggesting the importance of a central nervous system. In the next step, in order to generate the chaotic dynamics in circulation, electrical simulation model of a left heart circulation with a feed back loop with some delay were tested and we found that we can make chaos in circulation by the feedback loop. Thus, we had constitute the artificial baroreflex system with an artificial heart system and found that we can make chaos in animal model. And finally we proposed the clinical application of these methodology for the diagnosis of an autonomic nervous system and found that it may be useful. These findings may be useful for analyzing the nonlinear dynamics in circulation.][The clinical significance of the chaotic dynamics in the cardiovascular system had attracted attention. Circulation system is a kind of "complex system" having many feedback circuits. So, it was very difficult to investigate the origin of chaos in the circulatory system. In this study, we investigated the origin of chaos by the use of the methodology of the open loop analysis with an artificial heart, which did not have any fluctuation in their own pumping rate and contraction power, in the chronic animal experiments using healthy adult goats. As a result, in the circulatory time series data of the artificial heart, which did not have any fluctuation, low dimensional deterministic chaos was discovered by the methodology of nonlinear mathematical analyzing technique, suggesting the importance of the blood vessel system in the chaotic dynamics of the cardiovascular system. To investigate the origin of chaos furthermore, sympathetic nerve activity was directly measured in the animal experiments with artificial heart circulation. Chaotic dynamics was also recognized in the sympathetic nerve action potentials, even during artificial heart circulation, suggesting the importance of a central nervous system. In the next step, in order to generate the chaotic dynamics in circulation, electrical simulation model of a left heart circulation with a feed back loop with some delay were tested and we found that we can make chaos in circulation by the feedback loop. Thus, we had constitute the artificial baroreflex system with an artificial heart system and found that we can make chaos in animal model. And finally we proposed the clinical application of these methodology for the diagnosis of an autonomic nervous system and found that it may be useful. These findings may be useful for analyzing the nonlinear dynamics in circulation.]
  • Making of the feedback loop in circulation by an artificial heart system - (matched in title)(matched in title)
  • Making of chaos - [We could constitute the feedback loop for an artificial heart automatic control algorithm by the use of an autonomic nerve discharges or Mayer wave in peripheral vascular resistances, and or so. It may be make a complicated structures in time series data as メcomplex systemモ like chaos or fractal.][3, Simulation only of the systemic circulation by left heart]
  • Sympathetic nerve discharges during artificial heart circulation - (matched in title)(matched in title)
  • Nonlinear dynamics of an artificial baroreflex system. - (matched in title)[In linear systems, attractors are, of course, not strange. Attractors of ordinary differential equations with a degree of freedom below 2 are limited to either a fixed point or a limited cycle, and have proved not to be strange. In a strange attractor, the stretching and folding operations smear out the initial volume, thereby destroying the initial information as the system evolves and the dynamics create new information. In this study, to evaluate the circulation with the TAH with experimentally constructed baroreflex system from the viewpoint of the whole system, the hemodynamic parameters with TAH were analyzed by nonlinear mathematical analyzing techniques useful in the study of deterministic chaos. Hemodynamic parameters were recorded and analyzed in chronic animal experiments using healthy adult goats.]
  • Open loop analysis by the use of an artificial heart - (matched in title)[In order to develop an optimal automatic control algorithm of an artificial heart system for the creatures, investigation of the basic characteristics of the cardiovascular system may be important. The clinical significance of the chaotic dynamics had attracted attention, especially in the cardiovascular system, which had nonlinear dynamic behaviors [1,2]. Circulation system is a kind of "complex system" having many feedback circuits, so, it was very difficult to investigate the origin of chaos in the circulatory system.]
  • Future planning - [!! Artificial Organs][* Control for nonpulsatile circulation = Ozoecchi team]
  • Vagal nerve activity and information processing - [For the Quality of life (QOL) of the patients with the artificial heart system, monitoring of an information of the cardiovascular control system may be important. We’ve been evaluating an autonomic nervous system for that purpose, and recently fluctuations in hemodynamic parameters including heart rate variability (HRV) were evaluated by the use of spectral analysis and nonlinear mathematical analysis. Respiratory wave in HRV were thoght to be reflect ongoing information of the parasympathetic nerve activity. Is it true ? In order to confirm this hypothesis, we recorded vagal nerve activity directly in chronic cnimal experiments. Six healthy adult goats were anesthetized with Halothene inhalation and thoracotomy were performed by the fourth lib resection during mechanical ventilation. Arterial blood pressure, right and left atrial pressures were continuously monitored with the catheter insertion. Cardiac output were measured by the electromagnetic flowmeter attached to the ascending aorta. After the chest was closed, incision were made to the left neck and left vagal nerve were separated. Stainless steel electrodes were inserted into the vagal nerve and fixed by the plasticizer. After an incision was closed, the goats were transferred to the cage and extubated after waking. Hemodynamic parameters and vagal nerve activity were measured in the awake condition. The results showed that clear observation of the autonomic nerve discharges were embodied by this experimental system. The vagal nerve discharges were synchronized with heart beat and respiration. And tonus of the vagal nerve were significantly influenced by the hemodynamic alteration. However, respiratory wave did not always accord with tonus of the vagal nerve activity in some condition, suggesting that we must check another information to evaluate the parasympathetic tone. We must continue this study to evaluate an tunonomic nervous system during artificial heart circulation.][For the Quality of life (QOL) of the patients with the artificial heart system, monitoring of an information of the cardiovascular control system may be important. We’ve been evaluating an autonomic nervous system for that purpose, and recently fluctuations in hemodynamic parameters including heart rate variability (HRV) were evaluated by the use of spectral analysis and nonlinear mathematical analysis. Respiratory wave in HRV were thoght to be reflect ongoing information of the parasympathetic nerve activity. Is it true ? In order to confirm this hypothesis, we recorded vagal nerve activity directly in chronic cnimal experiments. Six healthy adult goats were anesthetized with Halothene inhalation and thoracotomy were performed by the fourth lib resection during mechanical ventilation. Arterial blood pressure, right and left atrial pressures were continuously monitored with the catheter insertion. Cardiac output were measured by the electromagnetic flowmeter attached to the ascending aorta. After the chest was closed, incision were made to the left neck and left vagal nerve were separated. Stainless steel electrodes were inserted into the vagal nerve and fixed by the plasticizer. After an incision was closed, the goats were transferred to the cage and extubated after waking. Hemodynamic parameters and vagal nerve activity were measured in the awake condition. The results showed that clear observation of the autonomic nerve discharges were embodied by this experimental system. The vagal nerve discharges were synchronized with heart beat and respiration. And tonus of the vagal nerve were significantly influenced by the hemodynamic alteration. However, respiratory wave did not always accord with tonus of the vagal nerve activity in some condition, suggesting that we must check another information to evaluate the parasympathetic tone. We must continue this study to evaluate an tunonomic nervous system during artificial heart circulation.]
  • PDE阻害薬の強心作用とEmaxのカオス的ダイナミクス - [# Yambe T, Nitta S, Sonobe T, Naganuma S, Kakinuma Y, Izutsu K, Akiho H, Kobayashi S, Ohsawa N, Nanka S, Tanaka M, Fukuju T, Miura M, Uchida N, Sato N, Tabayashi K, Koide S, Abe K, Takeda H, Yoshizawa M: Deterministic chaos in the hemodynamics of an artificial heart. ASAIO J 41: 84-88, 1995.][# Maskin CS, Sinoway L, Chadwick B, Sonnenblick EH, Le Jemtel TH. Sustained hemodynamic and clinical effects of a new cardiotonic agent, WIN 47203, in patients with severe congestive heart failure. Circulation. 1983 May;67(5):1065-70.]
  • 論文・出版リスト - 西條先生分 - [# Saijo Y, Sasaki H, Okawai H, Yambe T, Nitta S. Visualization of inner surface morphology of artificial heart by scanning acoustic microscopy. Proc 2nd International Congress on Robotics, Vision, Parallel Processing for Industrial Automation; 51-54, 1996.][# Saijo Y, Jorgensen C, Falk E, Nitta S. Collagen characterization of fibrous caps in Apo-E deficient mice by acoustic microscopy. Circulation Vol. 100, No. 18; I-251, 1999.]
13 page(s) containing the phrase 'Artificial', 'Circulation' were found in a set of 269 pages.
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