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Biomedical subjects

T Nicholson

Publications and source records attributed to T Nicholson.

51 records · Page 3Linked to original sources
PubMed1982

Turbulent times.

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Nursing Services↗
PubMed1982

The mode of action of intravenous pentagastrin injections on forestomach motility of sheep.

The investigation involved the recording of pressure changes in the reticulum and rumen of sheep. Rapid, intravenous injection of pentagastrin (0.2-1.0 microgram/kg body wt.) inhibited motility during eating and rumination as well as in sheep at rest. In anaesthetized sheep, after bilateral cervical vagotomy, contractions of the reticulum and rumen produced by stimulation of the vagus nerve were not prevented by pentagastrin injections (0.2-1.0 microgram/kg body wt.). In anaesthetized sheep with the left vagus nerve intact, stimulation of the central end of the right vagus nerve failed to elicit reflex contractions of the reticulum for 210-390 s after the intravenous injection of pentagastrin (0.6-0.7 microgram/kg body wt.).

Animals↗
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Effects of blood phase oscillation on gas transfer in a microporous intravascular lung.

It may be possible to design an intravascular membrane lung with gas transfer properties augmented by the natural flow oscillations in the venous and pulmonary circulation caused by the beating heart and ventilatory movements. The authors used a simple dye visualization technique, the Pierce-Donachy assist pump, and mass spectrometry to investigate these effects on membrane lungs made with tethered, blind-ended, microporous, polypropylene fibers using in vitro tests in water saturated with O2, CO2, and He. Prototypes were constructed on a 7.5 Fr pulmonary artery catheter. The fibers had an outer diameter (OD) of 380 microns and a wall thickness of 50 microns and were mounted on 4.8 mm OD sleeves. Control measurements were taken over a range of steady water flows from 0.4 l/min to 3 l/min. While pumping the same water flow rates with a roller pump, the Pierce-Donachy pump generated pulsatile flow at a rate of 45 beats/min and a systolic duration of 300 msec. This produced a phasic flow with an instantaneous average flow velocity varying from 0 to as high as 46 cm/sec. O2 and CO2 transfer increased by as much as 91% and 59%, respectively. The largest effects were seen at the lower water flow rates.

Artificial Organs↗