P. J. Byrne

Screening for amphetamine in human urine.

SummaryArapid method is described for the detection and qualitative analysis of amphetamine in human urine by extracting the urine in alkaline ether and screening for amphetamine by gas liquid chromatography. By taking advantage of the difference in retention times for amphetamine and nicotine contained in the samples, a procedure was developed for screening four samples for the presence of amphetamine in each run through the chromatographic column. The method is sensitive and rapid in execution. Twenty-eight samples can easily be extracted, and screened on one machine in two days. The presence of amphetamine can be confirmed by forming the acetone-amphetamine derivative which can then be compared with a standard.

Retrograde electrical pacing and its influence on the migrating motor complex of the canine jejunum

SummaryA STUDY was undertaken to evaluate the effect of retrograde electrical pacing on the mechanical component of the migrating myoelectrical complex. Jejunal transections and reanastomoses were performed on five dogs at 20 cms and 60 cms from the Ligament of Treitz. Electrical and motor activity were recorded using stainless steel electrodes and serosal strain gauges placed within the segment. Retrograde electrical pacing was achieved by electrical stimuli using electrodes just proximal to the distal transection. Each fasting dog was studied on four occasions with and without retrograde electrical pacing for two hours following the appearance of a migrating motor complex. In a separate study of fed dogs the times of reappearance of migrating motor complexes with or without pacing were compared. Results showed that retrograde pacing does not alter the migrating motor complex except in its frequency of contractions which were significantly increased (13.6 ± 0.3 versus 17.8 ± 0.4 per min, p<0.01 ). Retrograde electrical pacing did not significantly delay the reappearance of migrating motor complexes after feeding. These findings are consistent with the hypothesis that migrating motor complex propagation is controlled by extrinsic nerves and suggests that retrograde pacing will have little effect on transit during fasting.

Oesophageal manometry. A comparison of hydraulic and syringe catheter infusion systems using a simple hydrostatic bench model

A simple hydrostatic bench model is described which can be used to validate oesophageal intraluminal manometry measurements. Conventional syringe pump infusion was compared with the hydraulic capillary infusion system using this model. Accurate recording of pressure changes was achieved on the low compliance hydraulic system at infusion rates of 1 X 10(-8) m3 s-1 (0.6 ml min-1). To achieve comparable accuracy with syringe pump infusion, undesirably rapid infusion rates of 10.35 X 10(-8) m3 s-1 (6.2 ml min-1) were required. We believe that the hydrostatic bench model is a useful tool for checking the accuracy of infused catheter systems.