Last Minute (last + minute)

Distribution by Scientific Domains

Selected Abstracts

Last Minute: Emergency Medicine

Harvey Castro MD
No abstract is available for this article. [source]

Central and peripheral cardiovascular adaptations to exercise in endurance-trained children

ABSTRACT Stroke volume (SV) response to exercise depends on changes in cardiac filling, intrinsic myocardial contractility and left ventricular afterload. The aim of the present study was to identify whether these variables are influenced by endurance training in pre-pubertal children during a maximal cycle test. SV, cardiac output (Doppler echocardiography), left ventricular dimensions (time,movement echocardiography) as well as arterial pressure and systemic vascular resistances were assessed in 10 child cyclists (VO2max: 58.5 4.4 mL min,1 kg,1) and 13 untrained children (UTC) (VO2max: 45.9 6.7 mL min,1 kg,1). All variables were measured at the end of the resting period, during the final minute of each workload and during the last minute of the progressive maximal aerobic test. At rest and during exercise, stroke index was significantly higher in the child cyclists than in UTC. However, the SV patterns were strictly similar for both groups. Moreover, the patterns of diastolic and systolic left ventricular dimensions, and the pattern of systemic vascular resistance of the child cyclists mimicked those of the UTC. SV patterns, as well as their underlying mechanisms, were not altered by endurance training in children. This result implied that the higher maximal SV obtained in child cyclists depended on factors influencing resting SV, such as cardiac hypertrophy, augmented myocardium relaxation properties or expanded blood volume. [source]

Acute effects of escalating doses of amiodarone in isolated guinea pig hearts

Bicer, S., Patchell, J. S., Hamlin, D. M., Hamlin, R. L. Acute effects of escalating doses of amiodarone in isolated guinea pig hearts. J. vet Pharmacol. Therap.25, 221,226. Cardiac effects of escalating concentrations of amiodarone were determined on isolated perfused guinea pig hearts (Langendorff preparations). Spontaneously beating hearts were instrumented for the measurement of RR, PQ, QRS, QT and QTc durations (from a bipolar electrogram), and dP/dtmax and dP/dtmin from an isovolumetric left ventricular pressure curve. Ten hearts were exposed to escalating concentrations of amiodarone (10,7, 10,6, 10,5 and 10,4 M) in dimethyl sulfoxide (DMSO)/Krebs,Henseleit or to DMSO/Krebs,Henseleit (vehicle). Measurements were collected during the last minute of a 15-min concentration. Means of all parameters were compared by ANOVA with repeated measures design. When compared with vehicle, amiodarone prolonged QT and QTc durations at concentrations >10,6 M. The apparent lengthening of RR, PQ and QRS at concentrations >10,6 M did not achieve statistical significance. Similarly, the apparent decreases in dP/dtmax and dP/dtmin at concentrations >10,6 M did not achieve statistical significance. The putative therapeutic concentration of amiodarone is between 2 and 4 10,6 M. In this study, at a concentration of 10,6 M, only RR and dP/dtmin tended to change, but they were not different from vehicle. Thus, amiodarone in this preparation has little potential for cardiac toxicity at therapeutic concentrations. [source]

Who's in the Mirror?

Nine-Month-Old Infants, Other Discrimination in Specular Images by Four-
This research investigated the early determinants of self-other discrimination in infancy. Ninety-six 4- and 9-month-old infants were placed facing a live image either of themselves or of another person (experimenter) mimicking them. The specular image was either contingent (on-line), or contingent with a 2-s delay. After a first 1-min presentation, the video image of either the self or the other was suddenly frozen for 1 min (still-face episode). This was followed by a last minute of live presentation. From 4 months of age, infants appeared to perceive and act differentially when facing the specular image of themselves or the mimicking other. In general, infants tended to smile more, look more, and have more protracted first-look duration toward the mimicking other compared with the self. Developmentally, 9-month-olds showed markedly more social initiatives toward the mimicking other compared with the self during the still-face episode. In all, these results indicate that infants develop self-other discrimination in specular images long before mirror self-recognition, which is typically reported by the second year. Discrimination of the self from other is interpreted as a precursory ability and a perceptual foundation of later conceptual self development. [source]

Cardiovascular patterns associated with threat and challenge appraisals: A within-subjects analysis

Karen S. Quigley
Previous studies demonstrated distinct cardiovascular patterns associated with threat and challenge appraisals for groups of participants. We extend these results by assessing whether appraisals continue to be associated with these cardiovascular response patterns within an individual as appraisals change. Participants completed four verbal mental arithmetic tasks for which they made appraisals before and after each task. Cardiac reactivity and total peripheral resistance (TPR) were calculated for the first and last minutes of each task, and the number of responses and percent correct were measured for each task. In line with our prediction, pretask appraisals were related to some task-related cardiac responses across the four tasks. In addition, task-related cardiovascular reactivity and behaviors both influenced appraisals following the task. Our findings suggest that an idiographic analysis of appraisals, cardiovascular physiology, and task-related behaviors provides a richer understanding of the appraisal process and reveals sex differences deserving further assessment. [source]