So-called Darwinism was originally proposed in 1859 to elucidate the diversity of living organisms. This concept, however, was soon introduced to explain the vicissitudes of other various phenomena in many different fields. In this paper, the developing processes of medical devices have been discussed from the standpoint of Darwinism and concluded as follows. Many important medical devices, e.g. pump-oxygenators for open heart surgery, assist-circulation systems including IABP and ECMO, cardiac assist devices and incubators for prematures have their own progenitors and such devices were all the products of evolution in medicine. On the contrary, artificial pneumothorax apparatuses lost the role as a counter-measure for phthisical lungs and suddenly disappeared about 40 years ago. It was an example of typical extinction resulted from natural selection as a process in evolution. The first shadowless design of surgical lightening was realized in early 20th century and almost at the same time the oil-pressure mechanism was introduced in the surgical tables. These incidents meant the evolution of such devices. But thereafter, any evolution has not occured again in those instruments during past 80 years, although many remarkable improvements have been achieved. From these experiences in this century, it was also pointed out that denying or converting the accepted concepts at present will contribute as the most important driving power to create and develop new medical devices in coming 21st century.
When X-rays are taken at home, both the patient and the patient's room are likely to be exposed to radiation. In this study, we measured the dose and investigated the problems that are anticipated with home-based radiographic examinations. A portable X-ray apparatus was used which operated with commercial power sources. This was a self-rectification device with a constant tube voltage. A chest X-ray examination was investigated, and, for comparison purposes, we measured the dose emitted by a mobile X-ray apparatus used inside hospital rooms. To obtain identical radiation density, the portable X-ray apparatus required approximately 1.7 times more incidence dose at the surface than the mobile X-ray apparatus, with 17.93 μC/kg for the former, and 10.26 μC/kg for the latter. When X-rays were taken with the patient standing in front of either a 10 cm thick wall or a shoji (paper) screen, the dose at the other side of the wall was 0.658 μC/kg, while the dose at the other side of a screen was roughly seven times that, or 3.540 μC/kg. When X-rays were taken on the second floor, the dose a floor below, inside the radiation area, and at 150 cm from the floor, was 0.153 μC/kg. Due to extremely poor radiation quality, the portable apparatus produced X-ray images of an inferior quality to those ordinarily taken inside hospital rooms. This study showed that, when taking X-rays in patients' homes, certain restrictions are deemed necessary to protect radiographers, caretakers, and other personnel from exposure.
The reliability and the effectiveness of the apparatus for continuous recording of sweating rate (Kenz Perspiro OSS-100) as the apparatus for measuring of the mental stress was discussed. The emotional sweating rates on solving the mathematical problems which were given as the mental stress were measured. The follwing was found out ; (a) The emotional sweating rates per second on solving the mathematical problems correlate with each other. (b) The normal variation of the emotional sweating rates is increasing according to the amount of the mental stress. From these results, the reliability and the effectiveness of the apparatus for continuous recording of sweating rate as the apparatus for measuring of the mental stress was indicated.
Leukocyte contaminations in the blood products have been shown to cause post-transfusion adverse effects. To eliminate those effects, leukocyte number in products has been recommended to be less than 1-5×10^6 per bag, however, apheresis machineries can not guarantee this level at present. Some modifications were introduced to Haemonetics Multi-component system, which made it possible to automatically filter platelet products during collection .The filter was set directly to the circuit line (in-line) or set between the collection bag and final bag (on-line). In-line filtration system decreased the contaminating leukocyte count less than 5×10^6 per bag furthermore, on-line filtration system guaranteed them to be less than 4×10^5 per bag. In addition, several platelet characteristics were similar to those of non-filtered platelets : pH, LDH, Glucose, Lactate, aggregation index, p-selectin and β-TG. Neither bradykinine nor inflammatory cytokines showed the increment during storage. These results indicated that on-line filtration/Multi-component system would be desirable to collect leukodepleted platelet products.