In this paper, description of clinical states of acute monocytic leukemia by means of mathematical models has been attempted. A differential equation model has been proposed to describe the relation between the input variables of administered drugs (daunomycin, Ara-C, 6-MPR and/or prednisolone) and the output variables of the number of leukemic and normal white blood cells in the peripheral blood. The model agreed well with clinical data obtained from two subjects, making it possible to predict the trend of clinical states for about 10 days ahead. From the parameters in differential equation, we could also estimate the clinically important quantities like the doubling rate constant of cells, the drug sensitivity and the duration of the drug effect.
The model here will be useful for planning and therapeutical course to induce leukemic patients to the remission state and also for classification of various leukemic states from the standpoint of their dynamical behaviours.

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In this paper, an indirect method of continuously measuring blood pressure is proposed. This method is based on the well-known relationship between arterial pressure and pulse wave velocity, that is, the arterial pressure can be estimated from the change of the pressure waveform.
In arteries, especially distal arteries such as the femoral artery, two obvious peaks are observed in the pressure waveforms. The systole causes the first one, and reflected waves at multiple sites in the arterial system cause the other one called the dicrotic wave. Taking the time interval between two peaks (T_a) and the pulse wave velocity into consideration, the most effective reflecting site is at or near the iliac artery, and T_a is the time the pulse wave takes to propagate between the aortic valve and this reflecting site.
It is well known that Young's modulus for a blood vessel increases in proportion to the arterial pressure and that this increase increases the pulse wave velocity. Therefore, T_a is inversely proportional to the arterial pressure, and so the change of arterial pressure can be calculated from the change of T_a.
T_a is determined from the autocorrelation function of the pressure waveform which is transcutaneously detected at the dorsal artery. In order to establish the relation between T_a and the arterial pressure, T_a is calibrated in corresponding pressure readings by the usual cuff method.
From results, we can see that the change of T_a is inversely proportional to the change of diastolic pressure. Therefore, the change of diastolic pressure can be estimated from the change of T_a within the measurement accuracy of about 5mmHg.

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This paper deals with a system for computer-aided analysis of two-dimensional sector scan echocardiograms and a method of reconstructing three-dimensional images of the left ventricle. The system is built of a minicomputer, a conventional ultrasound diagnostic instrument, a video tape recorder and special interface circuits which connect the instrument to the recorder and the minicomputer. The three-dimensional reconstruction of the left ventricle is performed by arranging several cross-sectional echocardiograms in their appropriate positions. In this paper, apical long axis view of the left ventricle is used to make clear the apical part of the left ventricle. The mutual positional relations of the cross sections are known by using a simple attachment on an arm to hold the probe at the same position and to fix the rotating axis of the probe.
The procedure of the three-dimensional reconstruction is as follows: Echocardiograms on several cross sections from the apex are recorded on a video tape with the ECG signals through the interface circuits. The consecutive echocardiograms of each cross section are quantized and transferred to the minicomputer. The contours of the left ventricular cavity are detected automatically by the minicomputer, and the detected contours at the same cardiac phase are rearranged around the rotating axis of the probe. These contours are connected with spline curves and sampled at 512 points which represent the three-dimensional shape of the left ventricle.
The three-dimensional shapes of the left ventricle at any cardiac phase are displayed on CRT by line segments or half-tone planes. Moreover, an animated pulsating left ventricle can be observed by displaying the three-dimensional images for one cardiac cycle repeatedly.
Useful indices on cardiac performance can be obtained from the reconstructed three-dimensional left ventricle. The volume is calculated by summing up the partial volumes of the three-dimensional left ventricle. Percent-shortening, which shows the contractility of the regional myocardium, is displayed in pseudo color on the silhouette of the left ventricle. These results are helpful in evaluation of cardiac functions.

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In clinical practices the evaluation criteria presented by the Japanese Association of Orthopaedic Surgeons are followed in Japan. These evaluation criteria consist of four items, namely WALK, PAIN, ADL, and ROM for each hip joint, which are scored on the basis of maximum 100 points. However, the evaluation point attached to each item is decided for convenience' sake and the basis of scoring is unclear. So, improvement of point distribution has been carried out using the quantification theory, together with the result of objective gait evaluation of 228 patients with hip diseases. The result of objective gait evaluation is a synthetic value obtained by measuring joint angular displacement of lower extremities, floor reaction force, trajectory for a point of force application, temporal factor, and distance factor. The new evaluation criteria have following characteristics.
1) The point reveals linearity.
2) A evaluation point is assigned to each patient, not to each hip joint.
3) Evaluation items and point distribution are decided according to the characteristics of each patient's status, and the evaluation items do not contain redundant ones.
4) The total points show good agreement with the result of objective gait evaluation.

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In order to have a quantitative evaluation of transcutaneous P_O2 (tcP_O2) measurement, we have proposed a subcutaneous tissue oxygen transport model. On the steady-state solution of this model, tcP_O2 only depends upon the blood flow and the oxygen consumption rate in the subcutaneous tissue, not upon the oxygen diffusion area. The result of the experiment on six healthy adults using tcP_O2 electrode at 43°C, called blood interruption stress test, had good similarity to the model. When blood flow was stopped, tcP_O2 fell like a straight line with a time delay. And when it was recovered, tcP_O2 also recovered exponentially. The linear decrease of tcP_O2 on blood flow interruption means that the oxygen consumption rate in subcutaneous tissue does not depend upon oxygen pressure. This finding suggests that the oxygen consumption at the cell level takes place at any oxygen concentration level in its circumstance. From this dynamic response, we could calculate the parameter of this model, and the model suggests that the variety of skin O₂ diffusion resistance causes the main error of tcP_O2 measurement. These results suggest that this model explains the whole system of tcP_O2 measurement.

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In order to measure the mutual activity among any localized group of neurons, we have developed a magnetically coupled multimicroelectrode system, in which a permanently magnetized Pt-Co alloy was used as an electrode material. In this paper, we aim at developing a glass micropipette electrode coated with Ni ferromagnetic thin film, so that glass capillary electrodes may also be made available under the same multimicroelectrode system for purposes of intracellular recording and cell staining.
This paper sets forth the architecture of a newly developed glass electrode, fabrication techniques of Ni film, evaluation of film characteristics, optimal heat treatment condition of deposited film, and electrical properties between electrodes. Furthermore, the practicability is demonstrated by simultaneous recording of neural potentials from closely spaced neurons.

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This paper describes the relationship between the elastic properties of the shoulder muscle (trapezius) and patient's complaint about shoulder stiffness (neck pain). The elastic properties are measured applying a stepwise load to the shoulder muscle through a spherical indenter, which moves toward a balanced position with oscillation. To relate the subjective alternative choices, such as the complaint about the shoulder stiffness, with the elastic properties, the ratio of the number of complaints to the total has been used as a tentative scale for mapping out numerical values. Then with respect to the subjects including 83 patients, 14 female keypunchers and 9 healthy males, it has been found that neither the final displacement h nor the oscillation period τ alone showed clear correspondence with the subject's complaint. However, the product of h and τ was found to be suitable for evaluating the subject's complaint since the ratio decreased monotonically as the product increased.

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