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A multicentre study on the epidemiology of perinatal depression was conducted among Japanese women expecting the first baby (N = 290). The incidence rate of the onset of the DSM-III-R Major Depressive Episode during pregnancy (antenatal depression) and within 3 months after delivery (postnatal depression) were 5.6% and 5.0%, respectively. Women with antenatal depression were characterised by young age and negative attitude towards the current pregnancy, whereas women with postnatal depression were characterised by poor accommodation, dissatisfaction with sex of the newborn baby and with the emotional undermining. Antenatal depression was a major risk factor for postnatal depression.

This paper developed the LRT introduction effect simulator. The increase in the number of heat-trapping gases such as carbon dioxide is a global problem. Decreasing this number is essential. The thought is that a modal shift from the car to public transportation is effective in the traffic field. However, when public transportation is introduced, a quantitative effect is needed in Japan. The paper developed a simulator, whereby the selection of car, railway or bus, which has not been included in past simulators, is used to calculate the running energy of transportation. The simulator then reports the selection of the individual’s means, with the model being built using the Analytic Hierarchy Process.

We have developed a spatially resolved NIRS imaging system with novel optical probes and fast temporal resolution. Initial results showed the effectiveness of our system for real-time spatio-temporal analyses for muscle oxygenation during exercises.

Clinical applications of ultrasound contrast agent (UCA) have been widely studied in recent years, but the behavior of microbubbles exposed to ultrasound is not fully understood yet. The authors developed a high-magnification and high-speed observation system, and they studied the dynamic behavior of cavitation bubbles, air-contained microbubbles, and UCA under ultrasound exposure. The dynamic behavior of cavitation was observed at the frame rate of 2/spl times/10/sup 6/ frames/s with magnification of /spl times/15, and periodic expansion and shrinkage due to exposure to ultrasound were observed. The maximum diameter of a bubble was around 10 /spl mu/m in the expansion phase, and it was too small to observe in the compression phase. Air-contained microbubbles of 20-100 /spl mu/m in diameter and UCA of 3-5 /spl mu/m in diameter were also observed at the maximum imaging rate of 1/spl times/10/sup 7/ frames/s and maximum magnification of /spl times/100. Typically, microbubbles exposed to ultrasound pressure undergo repeated expansion and shrinkage and reach a critical size, then collapse.

We have developed a miniaturized ultrasonic probe mounted on an 18-G puncturing needle and applied it to the detection of a flow in a small vessel using a correlation technique. The flow in a small vessel was clearly distinguishable from other regions in correlation images, whereas discrimination was difficult in a conventional B-mode image.

Echo enhancers consist of microballoons and the authors aimed to investigate the thresholds of microballoon collapse of two different shell types. PVC-AN microballoon is a mimicking echo enhancer with a hard shell and Albunex(R) that is a commercially available albumin shelled echo enhancer. The thresholds of the microballoon collapse were analyzed by detecting subharmonic wave production. Scattered waveforms by PVC-AN that was diluted to 1/1000 with normal saline. The scattered waves from the microballoon were detected by a hydrophone and analyzed by a digital oscilloscope with a 10 bit A/D conversion rate. The spectrum was calculated with a fast Fourier transform applied to the leading 5 microseconds of the waveform. The authors concluded that the threshold of PVC-AN collapse exists between 1.5 to 2.25 W/cm/sup 2/ of ultrasound intensity. They however, could not determine the threshold of Albunex(R) that was diluted to 1/100 with normal saline, since subharmonics were recognized even by 0.1 W/cm/sup 2/ irradiation which was the lowest intensity in the authors' system.

The authors propose a new intravascular ultrasound (IVUS) imaging method that enables them to discriminate the vessel lumen by detecting movement in regions of blood flow and an atheroma. A correlation technique was used to detect the movement, because transverse flow detection is impossible by the Doppler technique. The authors developed an experimental system and obtained radial-scanned correlation images of a vascular phantom. Experimental results showed that the blood flow could be clearly discriminated from the atheroma, whereas discrimination was difficult in conventional B-mode images.

A highly advanced vacuum power fuse has been developed for general purpose protection in high voltage primary distribution systems.

1. Electrophysiological properties of soleus motoneurones in adult cats were examined with intracellular electrodes following alterations of activity of the soleus muscle induced by transection of the thoracic spinal cord or by conduction block of the muscle nerve with tetrodotoxin (TTX) cuffs. Attempts were also made to maintain muscle activity by daily stimulation of the maintain muscle activity by daily stimulation of the peripheral nerve. 2. Within 8 days after transection of the thoracic cord, soleus motoneurones showed a significant decrease in the duration of afterhyperpolarization following action potentials. This change in motoneurone properties induced by cord transection was prevented by daily stimulation of the sciatic nerve. 3. Soleus motoneurones showed a significant decrease in the duration of after-hyperpolarization within 8 days after conduction block of the soleus nerve with TTX. This change in montoneurone properties was prevented by daily stimulation of the nerve peripheral to the TTX cuff but not central to the cuff. 4. The soleus muscle showed a significant decrease in weight relative to body weight within 8 days after transection of the thoracic cord. This decrease in muscle weight following cord transection was prevented by daily stimulation of the sciatic nerve. 5. No fibrillation was detected in the soleus muscle 8 days after conduction block of the soleus nerve with TTX. The maximum twitch tension of the soleus muscle evoked by nerve stimulation showed no significant difference between the two sides treated and untreated with TTX. Fast axoplasmic transport measured with cholinesterase as a marker was not affected by TTX. Thus, there was no sign of functional although morphological abnormalities were found in some nerve fibres. 6. It is concluded that motoneurone properties in an adult depend partly upon some factors associated with activity of the innervated muscles and that such trophic signals are retrogradely carried by the motor axons.

Summary The obliteration processes of the ductus arteriosus of equine foetuses and newborn foals were studied morphometrically and histologically. The length, internal and external diameters and circumference of the ductus in equine foetuses increased progressively and linearly up to 310 days with advancing foetal age, but the values, especially the internal diameter, decreased from 320 to 330 days. After birth, the ductal measurements decreased gradually and ductal closure was found in three of 14 foals examined on the first day post partum, in two of six on the second day and in nine of nine on the third day or later, suggesting that the ductus arteriosus closes physiologically within three days after birth. Microscopical findings of the ductus arteriosus were characterised by the rearrangement of smooth muscle cells in the inner media and intimai thickening in foetuses, and by the central displacement of the intima in newborn foals. It was concluded that the ductus arteriosus begins to undergo preparatory modifications during intrauterine life, when the vessel is still functional, and that the most significant starting point of change in the obliteration processes is the rearrangement of smooth muscle cells in the inner media, which occurs during pre- and post natal life.

The properties and development of the stretch reflex pathway were investigated in new-born and fetal rats using the isolated spinal cord-hind limb preparation. Muscle afferent discharge was elicited by small stretch of the triceps surae muscle in the new-born rat and in the fetus. It appeared as early as embryonic day 18.5. Ramp-and-hold stretch elicited only phasic discharges in most afferent fibres. A phasic reflex response was evoked in the triceps surae muscle by brief or ramp-and-hold stretch of the muscle in the new-born rat. The threshold stretch required for evoking the reflex response was close to that for eliciting the afferent discharge. A reflex response in the triceps surae muscle was also evoked by electrical stimulation of the triceps surae muscle nerve or the sciatic nerve in the new-born rat. Excitatory post-synaptic potentials (e.p.s.p.s) in the triceps surae motoneurones were evoked by stimulation of the muscle nerve in the new-born rat. The amplitude of the e.p.s.p.s was large enough to generate spike potentials. Homonymous e.p.s.p.s were significantly larger than heteronymous e.p.s.p.s. The amplitudes of the e.p.s.p.s were very susceptible to the rate of stimulus repetition. At a stimulus frequency of 10 Hz they were depressed to less than 10% of the control value. Presynaptic impulses evoked by stimulation of afferents in the muscle nerve appear in the motor nucleus less than 1.0 ms before the onset of synaptically evoked field potentials. The interval between the arrival of impulses evoked by dorsal root stimulation and the onset of e.p.s.p.s in motoneurones was 0.56 +/- 0.16 ms, indicating monosynaptic transmission from the primary afferents to the motoneurones. In the fetus, a reflex response in the triceps surae muscle was observed following a small stretch of the muscle (or electrical stimulation of the sciatic nerve) in all preparations at embryonic day 20.5 and in about half of those examined at embryonic day 19.5. Neither stimulation evoked a reflex response at embryonic day 18.5. Latencies of the reflex responses evoked by muscle stretch or by nerve stimulation were similar to those in the new-born rat. It is concluded that the monosynaptically evoked stretch reflex response in the triceps surae muscle first appear at embryonic day 19.5. Natural and electrical stimulation of the plantar skin evoked a reflex response with long latencies in flexor muscles. Such a cutaneous reflex was first present at embryonic day 17.5, two days earlier than the onset of the stretch reflex.