During the investigation of the neuromuscular transmission process in myasthenia gravis, the results of which have been published in a previous paper (Elmqvist, Hofmann, Kugelberg & Quastel, 1964), one of the problems encountered was to determine what constitutes normal behaviour of end-plate potentials under a variety of conditions. It was found that for a quantitative investigation human intercostal muscle was in some ways more suitable than the more conventional rat phrenic-diaphragm preparation. Even with moderate rates of stimulation the variation in amplitude of sequential end-plate potentials (e.p.p.s) was sufficient to permit reasonably accurate estimations of quantum size and quantum content, providing a basis upon which release of transmitter could be compared from junction to junction and under different environmental and stimulation conditions. We have therefore continued to use this preparation for the investigation of the effects on transmitter release of repetitive nerve stimulation of varied frequency and duration, and also the effects of changed calcium and magnesium concentrations.The experiments done were in some aspects similar to those previously reported by a number

Sleep was studied in nine patients for two to four days after major non-cardiac surgery by continuous polygraphic recording of electroencephalogram, electrooculogram, and electromyogram. Presumed optimal conditions for sleep were provided by a concerted effort by staff to offer constant pain relief and reduce environmental disturbance to a minimum.All patients were severely deprived of sleep compared with normal. The mean cumulative sleep time (stage 1 excluded) for the first two nights, daytime sleep included, was less than two hours a night. Stages 3 and 4 and rapid eye movement sleep were severely or completely suppressed. The sustained wakefulness could be attributed to pain and environmental disturbance to only minor degree. Sleep time as estimated by nursing staff was often grossly misjudged and consistently over-

No abstract

No abstract

No abstract