Chiyoshi Yoshimoto

Effect of reducing the shell area on the respiratory properties of chicken embryonic blood.

Abstract In hen eggs, the effect of reducing the shell area available for respiration on gas exchange in chicken embryonic blood has been studied. Gas exchange through the shell over either the air space or the narrow end was blocked by coating about one-fourth of the total shell surface with epoxy cement. P O 2 , P CO 2 , pH and Hct in the chorioallantoic venous blood were simultaneously measured at days 10, 12, 14,16 and 18. [HCO − 3 ], total-CO 2 , content in plasma and base excess were graphically determined. The respiratory parameters determined were significantly different between control group and coated groups, while the difference between the two coated groups was not statistically significant. The hatchability in coated groups was very poor and a few embryos died even after reaching the air by pipping. Thus, it appears that such embryos near hatching encounter physiologically critical limits concerning blood gas metabolism. No difference could be established in the contribution to the gas exchange between the shell area of the narrow end and the area over the air space.

Respiratory properties of chicken embryonic blood during development

Abstract Blood P O2 , P CO 2 and pH and Hct of chorioallantoic vein and artery in chicken embryos were simultaneously measured, and [HCO3−3], total-CO2 content in plasma and base excess were determined graphically by plotting P CO2 , pH and calculated Hb on the Siggaard-Andersen alignment nomogram. The experiment was carried out daily from the eighth day of incubation to the 18th day. P CO2 , [HCO3−], CO2 content and base excess gradually increase with time, while blood P O2 and pH decrease during development. The differences of these parameters between vein and artery are rather large in comparison with those in the adult human being; especially they are large in the middle stage of development and they become small with time. The changes in respiratory parameters determined have close correlation with the developing embryonic weight. It is suggested that the embryo encounters respiratory alkalosis with metabolic acidosis in the middle stage of development, and then the acid-base status approaches normal level with time.

An Optimally Controlled Respirator

An optimally controlled respirator was developed. It has three main features: 1) ventilation is controlled by the patients metabolic rate from continuously measured C0 2 output, 2) physiologic dead space approximated as a linear function of tidal volume is used to estimate alveolar ventilation, and 3) respiratory rate is computed to minimize ventilatory work.

The Optimal Cardiovascular Regulation of the Arterial Blood Pressure

The arterial pressure in animals is maintained within narrow limit over a wide range of body conditions inspite of many factors and functions involved. The baroreceptor reflexes qualify as the regulatory mechanism. The baroreceptor reflex composes a feedback control system which has the arterial pressure for its output. The system is concidered to operate around a particular set point of arterial pressure, above or below which changes in autonomic activities are evoked. However, under what principle, the regulation of arterial pressure is determined remains unsolved. Among many possibilities we have chosen the optimal criteria to be elucidated. The first indication of optimal relations in the cardiovascular function is found in Broemser’s paper (1935). Recently a few papers in this field have been proposed (Takaya,1972; Ono, et al, 1976; 1977; 1979; Kenner, 1974; Yamashiro, et al, 1978; Doubek, 1978; Suga, 1979).

Electrocardiographic potential distributions in newborn infants from 12 hours to 8 days after birth

Abstract Electrocardiographic potential distributions were studied in newborn infants whose ECGs change rapidly with days corresponding to the hemodynamic variations and adaptations. Chest ECGs were taken from 25 explored points on the anterior precordium, sampled every 2 msec., and quantitated by an average response computer. A digital computer was also used to compute bilinear interpolating values between adjacent explored points, and equipotential lines were printed on a line printer. The investigating period was from 12 hours to 8 days after birth. These potential distributions in infants were very different from those of adults and children, and showed clearly a pattern of right ventricular preponderance. This pattern could be seen during the investigating period, but distributions which might show increasing load on the left ventricle, and the left ventricular preponderance were observed in the latter days of investigation.

Inserted intrauterine transmitter for measurement of fetal heart rate

T~E F~rAL heart rate is important in monitoring the fetal condition throughout the delivery and for prognosis. The fetal electrocardiogram and phonocardiogram have been taken from the maternal abdomen or from the fetal scalp after the rupture of the amnionic sac to measure the fetal heart rate (FHR). However, these methods are not always efficient because of the poor signal to noise ratio, the difficulties of continuous monitoring and the possible unfavourable psychological effects upon some pregnant women. Hence, we constructed a small transmitter which could be easily inserted into the body, to obtain a FECG for the purpose of monitoring the FHR. The transmitter was inserted into the uterus after the beginning of labour and the transmitted F E C G was received by an ordinal short wave radio.

Health care technology and biomedical engineering in far eastern developing countries

The present status of health care technology in far eastern developing countries is surveyed and reported. It is argued that the coexistence of oriental and western medicines makes the problem of health care complicated in rural areas and that unification of these two medical sciences by scientific analyses is needed. Several examples of medical and biological engineering research in these countries are given.<<ETX>>