Human carotid arterial baroreceptors have been stimulated by applying subatmospheric pressures to a box enclosing the neck, and the cardiovascular responses to this stimulation have been observed. For each cardiac cycle, the heart rate, arterial pressure and stroke volume were measured in order that the transient cardiovascular behavior might be observed. The pressure in the box was gradually decreased and was then maintained at a constant level. Results obtained are as follows: (1) The heart rate decreases proportionately to the pressure in the box as the pressure is gradually decreased. After the pressure attains the constant level, the heart rate recovers slightly. These imply that the control mechanism of the heart rate including baroreceptors has differential characteristics. (2) Cardiac output and arterial pressure decrease soon after the pressure decreases. After the pressure reaches the constant level, cardiac output returns to the control value, whereas the arterial pressure hardly changes. This would suggest that the total peripheral vascular resistance decreases when the pressure decreases. Further, the experiments have been simulated by using a mathematical model of the whole vascular control mechanism which the authors had proposed. The simulated results were compared with the experimental ones. The comparison supports the implication described above about the characteristics of the baroreceptors.

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This paper deals with the automatic cyto-screening system by the so-called scanning method, in which the morphological features of uterocervical cancer cells on a präparat are characterized by means of the pattern recognition technique. And a new method of cell dispersion as the preparation step and a novel sub-system for image input have been introduced. A new cell dispersion apparatus based on a syringing techniques has been developed, and its performances evaluated in terms of dispersion capability on individual cell level as well as of its influence on system judgement on präparat level are discussed to confirm its adaptation to the main system. The color characteristics of cells stained by the Papanicolaou's method, commonly used in cyto-screening, have been analyzed to determine the color characteristics best suited to the input. Finally, the results of field tests using an automatic system fabricated on the basis of these studies are presented to show the potential of its practical application.

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This paper describes a design of a feedback control system maintaining the arterial CO₂ partial pressure near the normal level by artificial respiration against disturbances such as CO₂ production rate, dead space, and blood flow. The controlled system is approximated by a linear model. By its aid a proportional controller with a lag-lead compensator is designed to satisfy the requirements arising from the performance of the biological respiratory system. It has been confirmed by simulation that the control system had good responses to the above-stated disturbances, and that it was little affected by the parameter variations in the controlled system.

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Though the distance and temporal factors of gait are the most important and fundamental variable parameters to describe and evaluate gait format, they have not been fully utilized for gait analytical study for lack of such equipment system adequate for taking and recording those factors automatically.
Hitherto, the above factors of gait have been obtained frequently from measured data with foot prints, pedoscope, foor floor contact patterns measuring system, instrumented shoes, and so on. Such semi-manual procedures, however, has required much time and labor to take data enough to perform statistical processing.
So, the authors have newly developed a measuring equipment system for gait analysis, which is constructed with a wired walkway platform, an electric circuit controller, and a microprocessing computer. Then, a train of processing works, from the data input to the evaluating results output, via the describing of gait format, has been successfully automated.

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Gradation is very important in the image-diagnosis of a tissue by ultrasonotomography. This paper is concerned with the high-gradation display method using both black and white and color monitors.
Ultrasonotomograms are programably displayed in black and white so that any kind of gradation-characteristics may be obtained. Color has good discrimination, but it yields sometimes less recognizable whole image of a tissue. In order to improve it and to provide effective diagnosis a coloring method has been introduced in such a way that (1) a continuous luminance curve be based on a B/W monitor, (2) possible colors limited by the luminance be specified successively so that the gradation levels of picture elements should be continuous in luminance and chromaticity.
These computations and processings are implemented by a built-in microcomputer. Besides, the developed imaging system displays the gradated images fast without losing the original ultrasonotomogram.

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