Biomedical subjects
Publications and source records attributed to J S Tiedeman.
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Two chemical derivatives of delta-1-tetrahydrocannabinol were evaluated in a randomized, double-masked study, administered as a single oral dose to a group of ocular hypertensive patients. One of the compounds (BW146Y) was found to have a significant intraocular pressure lowering effect that was independent of orthostatic blood pressure changes, although such changes did occur in some patients. The other compound (BW29Y) was ineffective in lowering intraocular pressure at the doses tested. Psychological and performance parameters were measured, and except for a time production test among the BW29Y group, these parameters were not significantly affected by the test drugs. Patients receiving both drugs experienced mild subjective side effects.
The electrophysiologic effects of intravenously administered disopyramide (2 mg/kg) on three parameters of sinus node function were examined in 16 symptomatic patients with sinus node dysfunction. Based on their ECG data before study, patients were subdivided into group A (n = 8), those with sinus pauses and/or sinoatrial (SA) exit block; and group B (n = 8), those with sinus bradycardia. Disopyramide shortened spontaneous cycle length in 10 of 16 patients and lengthened it in six--markedly so (91%) in one patient. Estimated SA conduction time decreased in seven of 14 patients and increased in seven. Two patients developed second degree SA exit block after disopyramide. Maximum sinus node recovery time was prolonged by disopyramide in 11 of 16 patients and markedly so in four. For the group as a whole there was no significant difference in spontaneous cycle length, maximum sinus node recovery time or estimated SA conduction time. P-wave and QRS durations and H-V intervals were significantly lengthened by disopyramide. Marked depression of the three parameters of sinus node function occurred in three group A patients and in one group B patient who had persistent severe sinus bradycardia. These four patients also had secondary pauses after termination of rapid atrial pacing under control conditions. Disopyramide should be administered cautiously to patients with sinus node dysfunction, particularly those with sinus pauses, SA exit block or secondary pauses.
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A circiut was designed for measuring maximum negative or positive potentials occurring during an action potential. The basic functional unit is a peak-holding circuit that is reset following each action potential. The output of the circuit is displayed on a digital meter and may also be used to drive a point plotter for a graphic presentation of data.