An automated voice advisory manikin system for training in basic life support without an instructor. A novel approach to CPR training.

Twenty-four paramedic students with previous basic life support training were randomised, performing cardiopulmonary resuscitation (CPR) on a manikin for 3 min without any feedback followed by 3 min of CPR with audio feedback from the manikin after a 2-min break, or vice versa. A computer recorded information on timing, ventilation flow rates and volumes and all movements of the sternum of the manikin. The software allowed acceptable limits to be set for all ventilation and compression/release variables giving appropriate on-line audio feedback according to these settings from among approximately 40 pre-recorded messages. Students who started without feedback significantly improved after feedback in terms of the median percentage of correct inflations (from 2 to 64%), with most inflations being rapid before feedback (94%), compressions of correct depth (from 32 to 92%), and the duration of compressions in the duty cycle (from 41 to 44%). There were no problems with the median compression rate, sternal release during decompressions, or the hand position, even before feedback. There were no significant differences in any variables with and without feedback for the students who started with feedback, or between the audio feedback periods of the two groups. It is concluded that this automated voice advisory manikin system, a novel approach to basic CPR training, caused an immediate improvement in the skills performance of paramedic students.

Fe reduction in cell walls of soybean roots.

Reduction of Fe(III)EDTA by excised roots of soybean seedlings (Glycine max L.) is stimulated by l-malate in the bathing solution. Reduction occurs much more rapidly with roots of seedlings grown in the absence of iron than with roots of seedlings grown with iron. Cell-wall preparations from these roots catalyze reduction of Fe(III)EDTA by NADH. They also contain NAD(+)-dependent l-malate dehydrogenase. Enzymic activity of the cell-wall preparations is not affected by previous iron nutrition of the plants, but the amount of l-malate in the roots is increased when seedlings have been deprived of iron. We propose that reduction of iron before absorption by soybean roots occurs in the cell-wall space, with l-malate secreted from the roots serving as the source of electrons. Part of the iron reductase activity of the cell walls can be solubilized by extraction with 1 molar NaCl. The enzyme has been partially purified.

Sterol synthesis. High-pressure liquid chromatography of C27 sterol precursors of cholesterol.

Conditions have been described which permit the rapid (approximately 3.5 hr) column chromatographic separation of the acetate derivatives of a number of C27 sterol precursors of cholesterol differing only in the number and position of double bonds in the sterol nucleus. On columns containing muPorasil with hexane-benzene 9:1 as the eluting solvent, acetate derivatives of the delta5, delta8(14), delta8, delta7, delta8,7, delta 8,14, and delta7,14 sterols were separated.