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Biomedical subjects

M Mohri

Publications and source records attributed to M Mohri.

139 records · Page 8Linked to original sources

Body temperature and oxygen consumption of newborn rats at various ambient temperatures.

The thermogenic response and rectal temperature (Tre) of newborn rats (0 to 32 days old) on exposure to various ambient temperatures (Ta) were investigated. The O2 consumption (VO2 in ml . min-1 per 100 cm2 surface area) was measured for one rat at a time by means of a closed circuit system. The results were that (1) within the thermal neutral ranges, Tre stood at 36--37 degrees C regardless of the age and the value of VO2 was lowest at the age of 6--7 days, after this period increasing and reaching a level of 1.4 ml . min-1 . cm-2 X 10(-2) after 18--21 days old (the weaning period); (2) the thermogenic response to cold (delta VO2/--delta Ta) was higher at ages prior to the weaning period than after the weaning period; (3) in spite of the higher thermogenic responses, Tre decreased markedly on exposure to cold prior to the weaning period, because of a poor development of thermal insulation; and (4) the achievement of homeothermy of the rat at subneutral temperatures was observed after the weaning period.

Animals↗

Transcatheter embolization of bronchial collateral arteries prior to intracardiac operation for tetralogy of Fallot.

In a case of tetralogy of Fallot with numerous bronchial collateral arteries (BCA), the collateral arteries were successfully occluded by transcatheter embolization of Gelfoam and use of the Gianturco spring as a preliminary to intracardiac repair. Pulmonary embolism would not result from this procedure in the absence of large direct communications between collateral and pulmonary arteries. The femoral artery and vein were prepared for cannulation before the procedure, so that it would be possible to start assisted perfusion immediately if arterial PO2 fell after transcatheter embolization. The procedure is performed under fluoroscopic control.

Adult↗

Influence of hyperbaric environment on physiological tremor.

The effect of pressured environment from 1 to 24 ATA (Atmosphere Absolute) on total power spectrum (TP) of physiological tremor, whose value was the sum of power spectra for frequency range in 0.5-50 Hz, was investigated. The main effects obtained were as follows. (1) In the case of 3 ATA, TP during the pressure holding period denoted a similar value as the value in 1 ATA. In the latter half of the period, the TP increased. When the pressured environment is 4 ATA, in which the partial pressure of the nitrogen gas was 3.6 ATA, the TP decreased during the pressure holding period compared with the value in 1 ATA. Nitrogen narcosis was recognized at the partial pressure of 3.6 ATA, thus the effect denoted a decrease of TP. (2) In the cases of 16 and 19 ATA using heliox gas, during the pressure holding period, TP decreased compared with the value in 1 ATA, but in the case of 24 ATA the value increased. The partial pressure of helium gas of 23.6 ATA indicated a high pressure nervous syndrome, therefore, the influence of high pressure on TP was recognized as one of the causes of the increase of TP. (3) The influence of inhibitors of the autonomic nervous system on TP during the pressure holding period of 3 ATA was recognized. After intake of the inhibitor for the parasympathetic nerve (atropine) during the pressure period, TP increased, while for the intake of the inhibitor for the sympathetic nerve (propanol), TP decreased.

Atmospheric Pressure↗

Effects of 30-m nitrox saturation dive on the immune system in man.

Hyperbaria reportedly affects the immune system, but the role of psychological factors arising from confinement has not been taken into consideration. We investigated the immune changes in 4 subjects exposed to a 9-day simulated 30-m (400-kPa) nitrogen-oxygen (nitrox) saturation dive, and compared the results with those of our previous study that showed immune and mood changes in normobaric confinement. Blood samples were taken before, during, and after the dive or confinement, and activated with an anti-CD2 agonistic antibody. The percentages of granulocytes, natural killer (NK) cells, and cells positive for CD69, an early activation marker, were analyzed by flow cytometry. Reduction of CD69 expression percentage was observed under both hyperbaric and normobaric conditions. Percentages of innate immune cells, such as granulocytes and NK cells decreased or remained mostly unchanged, contrasting with our previous study, which demonstrated increases in both percentages coordinate with mood improvement. We conclude that these changes may have been triggered by suppression of sympathetic nerve activity that occurs in 30-m nitrox saturation hyperbaria.

Adult↗

Daily diving pattern of Korean and Japanese breath-hold divers (ama).

Daily diving patterns and thoracic skin and sea-water temperatures were recorded during the entire work shift of Korean female unassisted (cachido) and Japanese male unassisted and partly assisted (funado) divers using Underwater Physiological Data Loggers developed in Buffalo and Japan. All 3 groups of divers were studied during the summer of 1989 and 1990. Additional studies were conducted during the winter of 1991 on Korean female divers who, unlike Japanese divers, dive all year round. The water temperature of the diving grounds in summer was 24 degrees C in both Korea and Japan, and 10 degrees C during winter in Korea. Both Korean female and Japanese male cachido divers made 113-138 dives a day and stayed in the water a total of 170-200 min.day-1, of which only 52-63 min were spent diving submerged, and the remaining time at the water surface. These diving patterns were not different between female and male cachido divers. Compared with Japanese male divers, Korean female divers dived to a shallower depth (3.7 vs. 6.9 m) with shorter dive time (29 vs. 37 s) and shorter bottom time (14 vs. 18 s). Velocities of descent (0.72 vs. 0.47 m.s-1) and ascent (0.77 vs. 0.56 m.s-1) were also slower in female divers than in male divers. The diving pattern of Korean female divers was similar in both summer and winter. Although all cachido divers wore wet suits and thus were protected from severe cold stress, thoracic skin temperature decreased during a work shift by 7 degrees C in winter (vs. 1 degree C in summer) in Korean divers. Compared with Japanese male cachido divers, Japanese male funado divers stayed in the diving ground (including time in the boat) longer (201 vs. 305 min.day-1) but performed only 23 dives per day. The average diving depth (9.7 m), duration (69 s), and bottom time for each dive (45 s), however, were significantly greater in funados. The velocity of vertical descent (1.0 m.s-1) was also significantly greater in funados because they descend with a weight (8-12 kg). The rate of ascent was not different.

Body Temperature↗