Biomedical subjects

N Horimoto

Publications and source records attributed to N Horimoto.

22 records · Page 2Linked to original sources

PubMed1991

REM sleep determined using in utero penile tumescence in the human fetus at term.

To assess how REM/NREM periods can be linked to the determination of the REM/NREM sleep and/or awake state, we have investigated the relationship between the REM/NREM periods and penile tumescence in the human fetus. This study was made on 11 male fetuses from 36 to 41 weeks of gestation. Eye movement and penile tumescence were simultaneously examined with an observation window of 60 min, using two separate real-time ultrasound systems. The mean percentage of the total duration of penile tumescence during the REM period and that during the NREM period was 77.7 and 15.8%, respectively. In all cases, the total duration of penile tumescence during the REM period against REM duration was greater than the duration of tumescence during the NREM period against NREM duration with statistical significance. This indicates that the fetal penile tumescence is strongly associated with REM period and the REM period containing penile tumescence in the human fetus can be considered equivalent to REM sleep in utero. In addition, the finding that there exists a part of the REM period lacking penile tumescence suggests the possible origin of the awake state, brought about by advances in fetal development at this stage of gestation.

Female↗

PubMed1990

Fetal eye movement assessed with real-time ultrasonography: are there rapid and slow eye movements?

The goal of this study was to determine whether rapid eye movement and slow eye movement exist during the eye-movement period in the human fetus in utero. We studied 21 fetuses with real-time ultrasonography, 10 from 33 to 36 weeks and 11 from 37 to 41 weeks' gestation. We used the duration of eye-movement unit as a parameter and calculated the cumulative duration from the shortest to a given duration of eye movement per individual case. A scattergram of cumulative duration versus given duration obtained from all cases in each age group was analyzed with piecewise linear regression to search for a critical point(s). Critical given duration points were noted and reached statistical significance at 0.62 second and at 0.76 second during 33 to 36 and 37 to 40 weeks of gestation, respectively. These findings reveal two different types of eye movement: one with a duration of less than 0.6 to 0.8 second and the other with a duration of greater than 0.6 to 0.8 second. These findings are compatible with previous criteria on rapid and slow eye movements, respectively, at 33 weeks of gestation onward. The mean value of cumulative duration at the critical point increased from 29.0% between 33 and 36 weeks to 47.1% between 37 and 41 weeks of gestation, indicating an increase in the proportionate amount of time maintaining rapid eye movement as gestation advances.

Eye Movements↗

PubMed1990

Chronological development of the fetal stomach assessed using real-time ultrasound.

To elucidate processes involved in the developing fetal stomach in utero, we examined chronological changes in maximum longitudinal and anteroposterior gastric dimensions in 618 fetuses from 16 to 41 weeks of gestation, using real-time ultrasound. Three statistically critical points were evident at 26-27, 32-33, and 36-37 weeks of gestation. Both dimensions increased from 16-17 to 26-27 weeks, remained fairly constant between 26-27 and 32-33 weeks, increased again from 32-33 to 36-37 weeks, and then decreased from 36-37 weeks onwards. These findings suggest that there are four different phases underlying the development of gastric function in the human fetus, corresponding to the time-periods divided by the three critical points of gestational age.

Embryonic and Fetal Development↗

PubMed1989

Concurrence of mouthing movement and rapid eye movement/non-rapid eye movement phases with advance in gestation of the human fetus.

To evaluate whether mouthing movement in the human fetus is related to advance in gestational age and whether such movement is concurrent with rapid eye movement or non-rapid eye movement phases, 26 fetuses from 28 to 41 weeks' gestation were observed for 60 continuous minutes with real-time ultrasonography. It was evident that regular mouthing movement every 300 to 600 msec concurred with the non-rapid eye movement period, from 35 weeks' gestation to term. Random mouthing movements that occurred at a wide range of intervals from 300 msec to approximately 525 seconds were observed predominantly during the rapid eye movement period and were unrelated to advance in gestational age. These observations were discussed in relation to biologic implications.

Eye Movements↗