S Saffer | PubMed Health

PubMed1979

EEG and autonomic responding to verbal, spatial and emotionally arousing tasks: differences among adults, adolescents and inhalant abusers.

The present study investigated the physiological responses of an adolescent inhalant abuse group, an adolescent non-abuse group, and an adult non-abuse group elicited by three types of tasks: verbal, spatial, and emotionally arousing. Each group consisted of 10 male Mexican-American subjects. Bilateral EEG and electrodermal activity, as well as heart rate, were monitored. While exploring for possible heart rate and hemispheric alpha wave differences in response to predominantly verbal and spatial tasks, an attempt was also made to discover if electrodermal responses could be bilaterally differentiated. Another purpose of the study was to explore possible psychophysiological differences between a younger and older group, and between an inhalant abusing group and a non-abuse group, in response to the three types of tasks. Results indicated that attempts to produce task-related EEG hemispheric asymmetry were largely nonsuccessful. Bilateral electrodermal responses were also not greatly differentiated. It was suggested that stronger task manipulations were needed. Significant group differences were found for initial physiological response levels (adults demonstrated higher levels than the two adolescent groups) and for heart rate response to the emotionally arousing task (non-abusing subjects demonstrated greater heart rate acceleration than inhalant abusing subjects). It was suggested that group differences in initial levels occurred due to the adult groups's greater involvement in the experimental situation. Heart rate differences to the emotionally arousing situation were discussed in terms of Zuckerman's sensation seeking hypothesis.

Adolescent↗

PubMed1979

Functional characterization of left ventricular segmental responses during the initial 24 h and 1 wk after experimental canine myocardial infarction.

Characterization of the temporal evolution of resting segmental function and inotropic reserve after coronary occlusion may be important in evaluating attempts to salvage ischemic but non-necrotic myocardium. Accordingly, we chronically implanted up to six pairs of pulse-transit piezoelectric crystals in the left ventricular myocardium of dogs to measure segmental wall thickness. Segments were separated into groups according to the loss of net systolic thickening (NET) at 5 min postocclusion of the left anterior descending coronary artery in awake, unsedated dogs. Group 1 included segments with NET values of 67--100+ (percent control); group 2 between 67 and 0; and group 3 less than 0 (paradoxical motion). 5 min after coronary occlusion, group 1 NET was 92 +/- 5% (SEM) although significant decreases occurred in NET in group 2 (36 +/- 4%) and group 3 segments (-33 +/- 5%). Between 5 min and 24 h after coronary occlusion, no further significant changes occurred in NET in groups 1, 2, and 3 crystals. Some segments underwent further functional deterioration between 24 h and 1 wk after left anterior descending coronary artery occlusion, although no overall change occurred in segments with mild to moderate ischemic dysfunction. Segments with NET less than 0 at 24 h, on the other hand, exhibited a reduction in aneurysmal bulging between 24 h and 1 wk from -41 +/- 10 to -23 +/- 11% (n = 12, P = 0.02). Inotropic reserve was assessed with postextrasystolic potentiation (PESP) in 14 dogs, and with infusions of dopamine (11 dogs), and isoproterenol (13 dogs). PESP was the most potent intervention and produced a significant augmentation in NET in group 2 crystals at 1, 2, 4, 6,8, and 24 h after coronary occlusion but only at 1 and 2 h in NET in group 3 crystals. Thus, following experimental coronary occlusion, the evolution of ischemic segmental dysfunction is dynamic and variable. A significant degree of inotropic reserve, as assessed by PESP, dopamine, and isoproterenol, exists in segments with moderate ischemic dysfunction for 24 h but for only 2 h after coronary occlusion in those segments with the most severe ischemic dysfunction. In addition, at least some segmental sites with mild to moderate ischemic dysfunction at 24 h deteriorate further between 24 h and 1 wk after experimental coronary occlusion.

Animals↗

PubMed1977

Experimental infarct sizing using computer processing and a three-dimensional model.

A method for noninvasive sizing of myocardial infarction, in which data from technetium-99m stannous pyrophosphate scintigrams and a three-dimensional model were used, was tested on experimental, acute anterior infarcts in dogs. The results indicate that the method does size experimental anterior infarcts accurately, but further testing will be necessary to assess the capabilities of the technique for sizing other types of infarcts.

Animals↗