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Biomedical subjects

I Ninomiya

Publications and source records attributed to I Ninomiya.

At least 163 records · Page 9Linked to original sources
PubMed1979

A multichannel telemetry system for recording cardiovascular neural signals.

A multichannel telemetry system was developed for use with chronically instrumented unrestrained cats. This system can simultaneously record efferent and afferent cardiovascular neural signals, bioelectrical noise arising near the electrode recording the neural signals, EEG, ECG, and a standard calibration signal. The miniature (18 cm3), lightweight (24 g), telemeter is a five-channel, time-multiplexed, pulse width modulation (PWM)/FM device employing a high frequency subcarrier (60 kHz) and two sampling frequencies (30 kHz and 6 kHz). The device is powered by two small 120 mA . h silver oxide cells; it has an indoor transmission range of 10 m and can operate for 48 h. One channel transmits a standard signal (a square wave of 100 Hz and 200 mVp-p) used to monitor and regulate the system's performance. When the variation in either the amplitude or frequency of the standard signal is greater than 10% of the control value, the transmitted bioelectrical signals are automatically discarded.

Animals↗
PubMed1976

Reflex effects of thermal stimulation on sympathetic nerve activity to skin and kidney.

Effects of peripheral and central thermoreceptor reflexes on sympathetic nerve activity to the skin (SkNA) and kidney (RNA) were compared in anesthetized cats. Sudden warming of the skin produced a rapid increase of RNA, wheras sudden cooling produced a rapid increase of SkNA. When the bath temperature (TB) was 17.6, 29.7, and 41.9 degrees C, the normalized SkNA was 100, 82, and 48%, while the normalized RNA was 81, 90, and 100%, respectively. Similarly, under open baroceptor loop conditions, SkNA changed inversely with TB, while RNA changed proportionally to TB. Changes in the temperature of the whole brain including hypothalamus (Thy) modified the amplitude of grouped RNA and SkNA synchronously with the cardiac cycle. At TB of 32.4 degrees C, when Thy was altered in a range of 30-42 degrees C, SkNA reached a maximum level at a Thy of 38.4 degrees C, whereas RNA reached a maximum above 42 degrees C. In a Thy range of 38-42 degrees C, the slopes of the Thy-SkNA curve and Thy-RNA curve were 30 and +4%/degrees C, respectively. At Thy below 38 degrees C, SkNA and RNA changed in parallel with Thy. Continuous cooling of the skin modified the slope of the TB-SkNA curve, but a small change of Thy caused a shift of the TB-SkNA curve.

Animals↗
PubMed1976

Implantable electrode for recording nerve signals in awake animals.

An implantable electrode assembly consisting of collagen and metallic electrodes was constructed to measure simultaneously neural signals from the intact nerve and bioelectrical noises in awake animals. Mechanical artifacts, due to bodily movement, were negligibly small. The impedance of the collagen electrodes, measured in awake cats 6-7 days after implantation surgery, ranged from 39.8-11.5 komega at a frequency range of 20-5 kHz. Aortic nerve activity and renal nerve activity, measured in awake conditions using the collagen electrode, showed grouped activity synchronous with the cardiac cycle. Results indicate that most of the remal nerve activity was from postganglionic sympathetic fibers and was inhibited by the baroceptor reflex in the same cardiac cycle.

Animals↗