In order to describe and evaluate a gait pattern, which is rather complicated and variable, it is necessary to observe the distance and temporal factors of gait since they are terminal output variables of gait movement and are easily observable.
And yet the above factors have not been utilized constructively for gait analytical study for want of adequate instrument systems to pick up and record automatically the variables on those factors.
Therefore, the authors have developed the instrumented walkway system to measure the distance and temporal variables, employing a microprocessor. This system has advantage to take in all variables successively in a manner that does not require the subject to wear, or to be connected to, any apparatus, nor the experimenter to do intricate instrumentation.
Then, making the most of this system, the authors have collected a number of data concerning the free gait of normal adults, and basing upon the statistics derived from these data, have introduced general and valid results.

View full abstract

Many kinds of cardiac pacemaker have been used for cases with A-V block. But, most of them cannot increase the rate like the natural heart even under physiological change of metabolism. It is the purpose of this study to make the more physiological pacemaker, which changes the rate to maintain the adequate cardiac output for metabolic needs, such as exercise, excitement, fever and other disease.
As the body temperature usually shifts following the metabolic change, it will be useful to control the pacing rate. On the basis of this idea, pacemakers with the feedback mechanism by the body temperature were implanted in dogs, and the thermistor used in the generator was put in the right atrium to detect the venous blood temperature. After the pyrogenic drug, 2-4-Dinitrophenol, was given to the animals by mouth, the blood temperature gradually rose to above 41°C, and the pacing rate changed from 198.8±2.0 beats/min. at 37°C to 257.6±2.6 beats/min. at 41°C, and the cardiac output also increased from 2.23±0.48l/min. at 37.0°C to 4.15±0.53l/mm. at 41.0°C. The group to which this pacemaker was applied increased the cardiac output more significantly than the group with the fixed rate pacemaker at the high blood temperature of 39.6°C or above. The thermistor implanted in the right atrium of a dog for one month was involved in the tissue of atrial wall, and still could detect the change of temperature promptly.
It is concluded that the pacemaker sensitive to the blood temperature changes the rate to deliver adequate cardiac output for metabolic needs, and that the sensor works for a long time after the implantation.

View full abstract

The present study has been undertaken for the purpose of developing an effective computerized medical data management and analytic system. For this purpose, a relational data base management system HDM has been developed at the Hiroshima University by expanding the commercial data base management system Model 204 previously developed by CCA. The HDM has a combined system of statistical package SPSS and SAS for using Model 204 data under the file transfer approach.
About 70MB medical data bases have been constructed on the HDM files. This system is now used in order to perform statistical analysis of these medical data bases, and some important and effective results are being obtained.
This paper presents statistical results of electrophoresis data of 229 lung cancer patients' serum proteins as an example.

View full abstract

The principle and application of a new plethysmography using a radioisotope (RI) is described. This technique (RI plethysmography) is applied to the limb blood flow measurement in patients to whom RI has previously been administered for the purpose of routine angiography. In case of intravenous administration, RI is assumed to diffuse homogeneously into the blood. When venous occlusion of the forearm or the calf is performed in such subject, the RI count rate in a limb compartment increases according to the accumulation of the blood. The relationship between the changes of the count rate (ΔC) and the blood volume (ΔV) after venous occlusion can be expressed as
ΔV/V=β·ΔC/(C-C₀),
where V is the volume of the tissue compartment, β is the volume rate of the blood to the tissue (=V_b/V=2.5ml/100ml), and C and C₀ are the count rates of the compartment before venous occlusion and of the avascularization state, respectively. In this study, C₀ was tentatively determined by compressing the compartment using a pneumatic cuff with the pressure of more than 180mmHg. The blood flow per unit tissue volume can be calculated as the change in the blood volume per unit time (ΔV/V/Δt). Using this technique, calf blood flows of the patients with cardiovascular diseases have been measured and valuable results of the diagnosis of the disorders in peripheral circulation have been obtained.

View full abstract

A new type of fiberoptic transducer is proposed as a means of detecting blood pressure by utilizing a single polarization fiber (SPF) and photoelastic materials. Pressure sensing is based on the photoelastic effect of the small size element. Linearly polarized light from He-Ne laser is transmitted through the SPF to the photoelastic element attached to the tip of SPF. Linearly polarized light incident into the photoelastic element is affected by stress applied uniaxially and the change of the state of polarization is detected with the analyzer. The photoelastic elements that are the most important components of this transducer have been studied with respect to a large number of materials. As a result, it has been found that GaP {111} and epoxy resin were most appropriate. A model experiment to comfirm the operation of the transducer has been carried out by arranging the light source, each of optical elements, SPF and the photoelastic elements. Moreover, the prototype pressure transducer intended for catheter-tip micromanometer has been assembled and tested for hydrostatic pressure. The pressure transducer proposed has been found to have satisfactory properties in sensitivity, linearity and frequency response. Therefore, it is possible to develop a catheter-tip manometer smaller than 2.2mm in diameter (7F) and also to design a multifunctional all-fiberoptic transducer.

View full abstract