Department of Environmental Physiology

Professor : Shiraki, Keizo, MD and Ph.D.
Associate Professor : Sagawa, Sueko, Ph.D.
Assistant Professor : Endo, Yutaka, DDS and Ph.D.
Reserch Associate: Tsutsui, Yuka, MD

Research Topics

  1. Control mechanism of body fluid dynamics
  2. Physiological responses in hypebaric environments in humans
  3. Thermal and hemodynamic responses to extreme environments
  4. Physiology of the Ama

Key Words:

water immersion, body fluid balance, saturation dive, hyperbaric diuresis, sympathetic nerve activity, AVP, natriuresis, extreme environment

  1. Body fluid dynamics

    1. Body fluid response to head-up water immersion(Photograph 1)
      When the human body is immersed up to the neck, the blood of the lower extremities shifts in to the thorax cavity, which stimulates the cardiopulmonary baroreceptors.
      It is not only a simulation of body fluid movement in a weightless environment but also a good model for research of the hypervolemia. Research on the control mechanisms of body fluids is preceded by detailed examination of changes in the cardiovascular system, kidney function, endocrine system, and autonomic nervous system during head-out immersion.
    2. Recording of muscle sympathetic nerve activities. Further researches to clarify the role of sympathetic nerve activities on urinary volume and the sodium excretion are currently in progress.

  2. Physiological responses to saturation diving (Photograph 2)


    1. Characteristic changes have been observed in cardiac function, thermoregulatory functions, body fluid dynamics, and endocrine function during prolonged exposures in hyperbaric environments.
      An increased urine flow (high-pressure diuresis) during hyperbaric exposure is significant, and the kidney function and vasoactive hormones have been studied to elucidate the underlying mechanism.
    2. The spectral analysis of cardiac rhythms for an elucidation of autonomic nervous functions in relation to hyperbaric exposure have been studied. These researches have been made as cooperative works with the Japan Marine Science and Technology Center, State University of New York at Buffalo, Tripler Army Medical Center, and University of Hawaii.

  3. Thermal regulation in extreme barometric pressures, (Photograph 3, Photograph4)


    1. Body regulation during hyperthermic exposure simulated high and low atmospheric pressure has been studied, including thermal balance and sudomotor function.
    2. The orthostatic tolerance has been studied in simulated high altitudes.
    3. The carotid cardiac reflex has been studied at high altitude of 3,700m and 4,300m.

  4. Physiology of the Ama (Photograph 5)


    Thermal balance and cardiovascular functions of the ama, breath-hold divers have been studied in the Japanese and Korean ama in the ocean.
    This research has been a joint research with the Japan Marine Science and Technology Center, Kosin, Medical College, Pusan, Korea, State University of New York at Buffalo, and Department of Marine Sciences, University of Alaska.

  5. Dysrhythmia by stress

    A chronic administration of glucocorticoid or a long term exposure to stress cause functional disturbances and injuries in the hippocampus of rats. The dysrhythmia has been studied in relation to behavioral analysis in the rat.

Publications

Books and Chapters

  1. K. Shiraki, K. Nagaya, and S. Sagawa. Circulatory responses and sympathetic nerve activity during head-down tilt in humans. In Physiological Basis of Occupational Health: Stressful Environments. K. Shiraki, S. Sagawa, and M. K. Yousef (eds.). SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, pp. 85-95.
  2. R. Elsner, K. Shiraki, and M. Mohri. Seals and ama, animal and human diving experts. In Physiological Basis of Occupational Health: Stressful Environments. K. Shiraki, S. Sagawa, and M. K. Yousef (eds.). SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, pp. 127-135.
  3. J. R. Claybaugh, K. Shiraki, A. K. Sato, and P. B. Bennett. Work capacity in hyperbaric environment. In Physiological Basis of Occupational Health: Stressful Environments. K. Shiraki, S. Sagawa, and M. K. Yousef (eds.). SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, pp. 137-146.
  4. S. Sagawa, H. Takeuchi, M. Mohri, J. R. Claybaugh, K. Shiraki, and S. K. Hong. Body fluid balance and renal function during saturation dives. In Physiological Basis of Occupational Health: Stressful Environments. K. Shiraki, S. Sagawa, and M. K. Yousef (eds.). SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, pp. 147-155.
  5. K. Shiraki., J. R. Claybaugh. Effects of hyperbaria on physical capacity in humans. In The 1997 Nagano Symposium on Sports Sciences. H. Nose, E. R. Nadel, and T. Morimoto (eds.) Cooper Publishing Group, LLC, Carmel, IN., 1998, pp: 245-255.
  6. Keizo Shiraki, Sueko Sagawa, John R. Claybaugh and Motohiko Mohri. Renal and Endocrine Adaptation at Hyperbaria. in Adaptation Biology and Medicine (Vol. 2). K. B. Pandolf, N. Takeda and P. K. Singal (Eds). Narosa Publishing House, New Delhi, India, 1999, pp. 294-302.
  7. John R. Claybaugh, Beau J. Freund and Keizo Shiraki. Physical Performance Capacity in Hyperbaric Environments. in Adaptation Biology and Medicine (Vol. 2). K. B. Pandolf, N. Takeda and P. K. Singal (Eds). Narosa Publishing House, New Delhi, India, 1999, pp. 352-359.

Peer Reviewed Journals

  1. R. Torii, S. Sagawa, F. Wada, K. Nagaya, Y. Endo, F. Yamazaki, T. Nakamura, J. R. Claybaugh, and K. Shiraki. Mechanism for changes in vasopressin during acute exposure at 3 atm abs air. Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42 ): R259-R264, 1997.
  2. S. Sagawa, R. Torii, K. Nagaya, F. Wada, Y. Endo, and K. Shiraki. Carotid baroreflex control of heart rate during acute exposure to simulated altitudes of 3,800 m and 4,300 m. Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42 ): R1219-R1223, 1997.
  3. F. Yamazaki, S. Sagawa, R. Torii, Y. Endo, and K. Shiraki. Effects of acute hyperthermia on the carotid baroreflex control of heart rate in humans. Int. J. Biometeorol. 40: 200-205, 1997.
  4. Jang Kyu Choi, Kenju Miki, Sueko Sagawa, and Keizo Shiraki. Evaluation of mean skin temperature formulas by infrared thermography. International J. Biometeorology, 41: 68-75, 1997.
  5. F. Yamazaki, K. Shiraki, S. Sagawa, Y. Endo, R. Torii, H. Yamaguchi, M. Mohri, and Y. C. Lin. Assessment of cardiac autonomic nervous activities during heliox exposure at 24 atm abs. Aviat. Space and Environ. Med. 69: 643-646, 1998.
  6. K. Shiraki, R. Elsner, R. Torii, and M. Mohri. Lack of effect of 24 ATM ABS environment on face immersion bradycardia in human subjects. Undersea & Hyperbaric Med., 24: 189-190, 1998.
  7. F. Tajima, S. Sagawa, J. R. Claybaugh, ,and K. Shiraki. Renal, Endocrine, and Cardiovascular Responses during Head -out Water Immersion in Legless Men. Aviat. Space. Environ. Med., 70: 465-70, 1999.
  8. Yamaguchi, H., Mohri, M., and Shiraki, K. Evaluation of cutaneous insensible water loss during hyperbaric exposure in humans. Aviation, Space and Environmental Medicine, 70 (10); 990 - 995, 1999.
  9. J. E. Greenleaf, K. Shiraki, S. Sagawa, K. Miki, F. Wada, K. Nagaya, R. Torii and L. C. Keil. Is the Gauer-Henry reflex important for immersion diuresis in men? J. Aviation, Space and Environmental Medicine. 70: 1201-1205, 1999.
  10. F. Yamazaki, Y. Endo, R. Torii, S. Sagawa, And K. Shiraki. Continuous monitoring of change in hemodilution during water immersion in humans: effect of water temperature. Aviation, Space and Environmental Medicine, 71: 632-639, 2000.

Courses for medical students

Respiratory and circulatory systems
Kidney function
Endocrine system
Body temperature and its control mechanism
Environmental physiology
Hyperbaric physiology and medicine
Exercise physiology 　　　　　　　　　　　　　　　　　　　　　

Profile of staff

Professor : Shiraki, Keizo
Associate Professor : Sagawa, Sueko
Assistant Professor : Endo, Yutaka
Reserch Associate: Tsutsui, Yuka


Last updated: 8 June 2000