The shortening of the QT interval of the electrocardiogram coincident with acceleration of heart rate and vice versa has been accepted for many years as evidence that the action potential duration and hence QT are necessarily dependent on heart rate. Exceptions to this rule have been attributed to the intervention of counteracting autonomic effects. In order to test this assumption, 26 conscious dogs divided into three groups were tested during baroreceptor stimulation by a bolus injection of phenylephrine. Seventeen dogs had been used in earlier studies in which they had undergone an experimental anterior myocardial infarction with apparent full recovery. A group of those dogs underwent beta-adrenergic blockade by intravenous atenolol 30 min prior to the baroreceptor activation. To test the intactness of the baroreceptor responses in the previously infarcted dogs, a third group of nine dogs that had had no prior myocardial infarction was included. All dogs were adapted to the laboratory environment and were not sedated during experiments. Simultaneous recordings of RR, QT interval, and phasic arterial pressure were made in all dogs before and during baroreceptor stimulation. In the normal group, and the previously infarcted group that received no atenolol, baroreceptor stimulation elicited a small (8/msec), but significant prolongation of the QT associated with a nearly 50% reduction in heart rate. The QT interval of the atenolol-treated dogs, although significantly more prolonged before stimulation, remained unchanged during the reflex. The data indicate that withdrawal of ventricular sympathetic tone may prolong the QT interval, thereby confirming the role of sympathetic innervation in the control of QT.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
Predictors of myocardial infarction with or without survival were sought in a 30-year study of Roseto, Pennsylvania, a nearly exclusively Italian community of approximately 1,600, compared to the immediately adjacent town of Bangor with a population of approximately 5,000. At the start of the study the death rate from myocardial infarction among men in Roseto was less than half that in Bangor despite an equal prevalence of the usual risk factors, mainly smoking and diet. The communities were followed prospectively for 30 years during a striking social change in Roseto toward less family and community cohesion and more commitment to individual goals and adherence to materialistic values. During this period the prevalence of and mortality from myocardial infarction increased sharply to equal the situation in Bangor. The predictive values of measurements made of Rosetans during individual examinations in 1962-63 were tested against the outcome in 1990. Those who experienced fatal myocardial infarction and those who had a well documented infarction and survived were matched with and compared to controls. Although subjects with cholesterol concentration above 200 were twice as likely to experience myocardial infarction as those with concentrations below 200, less than 20% of those whose cholesterol concentration was above 200 experienced any evidence of myocardial infarction over the nearly 30-year period. Moreover, there were no significant differences between the coronary patients, with or without survival, and their sex, age, and cholesterol matched controls; nor were smoking, evidence of hypertension, diabetes, or obesity predictive of significant differences between the two groups. These data lead to the inference that while those with the conventional risk factors are more likely to develop myocardial infarction than are those without the risk factors, an even larger proportion of the population may have the risk factors and not succumb to myocardial infarction over a period of nearly three decades. 相似文献
This review examines recent books on altruism and prosocial behaviour. Psychological approaches, biological approaches, and economic approaches are covered. The list of variables known to influence prosocial behaviour includes situational determinants, motivational orientations, and personality variables. Psychological theories emphasizing norms, cost-benefit calculations, and developmental factors have been used successfully to explain prosocial behaviour. Attention is given to models of helping and social and therapeutic treatment programmes. Genetic variables in prosocial behaviour are also reviewed. 相似文献
A 16-yr-old retarded male, diagnosed organically blind and treated by those around him as a blind person, was given practice in discriminating visual stimuli. After training, he responded with significantly better than chance accuracy in a choice situation in which stimuli were as small as 18 pt Futura Medium type. In addition, he was trained to look at the experimenter's eyes when instructed to do so. Control procedures revealed that it was the reinforcement contingency that functioned to establish and maintain eye contact. Eye contact with the experimenter generalized in a limited way to situations in which this behavior was not reinforced, though not to a neutral individual. When the boy was required to use visual cues to help himself in a cafeteria line, he soon emitted the necessary behaviors, where formerly he had been assisted by others. Resumption of assistance markedly decreased self-help, suggesting that continued use of any newly learned skills would depend on the response of the individuals in his environment. The boy also learned eating behavior that appeared to require the use of visual cues. 相似文献
The present research focused on power processes in a simulated organizational structure consisting of three hierarchical levels occupied by different numbers of mules and females. Subjects were presented with a chart showing the organizational hierarchy of which they were a member placed at the lowest level, and asked to nominate any person for the leader position vacated by the current incumbent. The results of Experiment I (n = 88 Dutch male and female university students) showed that male subjects strongly overnominated themselves, whereas a majority of the female subjects nominated either self or another female. Of the others that were nominated by both males and females, almost all were occupants of positions immediately below the leader position, indicating the normative influence of a bureaucratic rule of leader succession. Experiment 2 was a replicational study carried out in a different culture (n = lOl Polish male and female university students). Polish subjects adhered to the bureaucratic rule more strongly than their Dutch counterparts, and both females and males nominated mostly males. Results are discussed with reference to gender self-stereotypes and cultural differences. 相似文献
Enlightenment East and West Leonard Angel, 1994 Albany, State University of New York Press 388 pp.
Visions of Power: Imagining Medieval Japanese Buddhism Bernard Faure, trans, by Phyius Brooks, 1996 Princeton, Princeton University Press 329 pp.
Pāli Buddhism. Curzon Studies in Asian Philosophy Frank J. Hoffman & Deegaixe Mahinda (Eds), 1996 Richmond, Curzon Press xiii + 233 pp., ISBN 0 7007 0359 4, hb £40
Friendship East and West: philosophical perspectives Oliver Leaman (Ed.), 1996 Richmond UK, Curzon Press ix + 288 pp., ISBN 0 7007 0358 6, hb £40
Heidegger's Hidden Sources: East Asian Influences on his work Reinhard May, trans, by GRAHAM PARKES, 1996 London, Routledge xviii+ 121 pp., hb £35.00, pb £11.99
The Social Self in Zen and American Pragmatism Steve Odin, 1996 Albany, SUNY Press xvi + 482 pp., ISBN 0 9714 2492 8, pb $24.95
The Art of living. Aesthetics of the Ordinary in World Spiritual Traditions Crispin Sartwell, 1995 Albany, State University of New York Press xiv+ 163 pp., hb
East‐West Encounters in Philosophy and Religion Ninian Smart & B. Srinivasa Murthy (Eds), 1997 London, Sangam Books xxiii + 411 pp., ISBN 0 8613 2375 0, hb £24.95
Confucianism and Christianity: a comparative study of Jen and Agape Xinzhong Yao, 1996 Brighton, Sussex Academic Press viii+ 164 pp., ISBN 1 8987 2325 7, hb £35 and $55 相似文献
Thirty‐Five Oriental Philosophers. Diane Collinson & Robert Wilkinson, 1994, London and New York, Routledge, vi + 205 pp., £35
Essays on Indian Philosophy Traditional and Modern. J. N. Mohanty (edited by Purushottama Bilimoria), 1993, Delhi, Oxford University Press, xxxvii + 347 pp., Rs. 500
Gates of Light (Sha'are Orah). Rabbi Joseph Gikatilla, 1994, London, Harper Collins, 400 + xxxiv pp., $30 相似文献