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41.
Angela J. Drake-Holland Mark I. M. Noble Sara Pugh Christopher Mills 《Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy》1988,2(2):239-243
Summary In this study any changes in action potential duration or Q-T interval due to acute doses of ketanserin were monitored. The effect of a bolus dose (10 or 20 mg) followed by an infusion (10 or 20 mg over 20 minutes) of ketanserin on the Q-T interval and action potential duration was studied in six patients undergoing routine cardiac catheterization. Action potential duration was measured with a silver-silver chloride electrode catheter while heart rate was kept constant by atrial pacing and reflex effects avoided by -adrenergic blockade. There were some prolongations of the action potential duration but they were not in excess of 40 msec and did not reach statistical significance (control 263±46.0 msec; bolus 269±52.1 msec; infusion 262±53.6 msec; nor were there any significant changes in Q-T interval. Thus acute intravenous doses of ketanserin, in the absence of hypokalaemia or other Q-T interval-prolonging drugs, have no consistent effect on Q-T interval or action potential duration; prolongation of the action potential, when it occurs, is small. 相似文献
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44.
Septal unit activity and hippocampal EEG during the sleep-wakefulness cycle of the rat 总被引:1,自引:0,他引:1
The functional relationship between septal unit activity and hippocampal EEG was studied during the sleep-wakefulness cycle in chronically implanted unrestrained rats. Results were statistically analyzed in order to obtain the time interval and auto and crosscorrelation histograms. During REM sleep and restless wakefulness the hippocampal EEG showed a theta rhythm of 4–8 cps and the septal unit activity was characterized by the presence of rhythmic bursts with a frequency in every single instance similar to that of the hippocampus. The septal units showed a bimodal time interval histogram. Their autocorrelation histogram exhibited a sinusoidal pattern of decreasing amplitude. The crosscorrelation histogram of septal units and the hippocampal EEG also showed a sinusoidal pattern suggestive of the functional relationship between both neural structures. During slow wave sleep and quiet wakefulness there was a disappearance of the hippocampal theta rhythm and rhythmic septal unit bursts. The second mode was missing in the time interval histogram and the auto and crosscorrelation histograms showed an irregular pattern. It is concluded that medial septal nucleus and hippocampal temporal patterns of activity are similar during REM sleep and restless wakefulness. 相似文献
45.
Mental fatigue and task control: planning and preparation 总被引:6,自引:0,他引:6
The effects of mental fatigue on planning and preparation for future actions were examined, using a task switching paradigm. Fatigue was induced by "time on task," with subjects performing a switch task continuously for 2 hr. Subjects had to alternate between tasks on every second trial, so that a new task set was required on every second trial. Manipulations of response-stimulus intervals (RSIs) were used to examine whether subjects prepared themselves for the task change. Behavioral measurements, event-related potentials (ERPs), and mood questionnaires were used to assess the effects of mental fatigue. Reaction times (RTs) were faster on trials in which no change in task set was required in comparison with switch trials, requiring a new task set. Long RSIs were used efficiently to prepare for the processing of subsequent stimuli. With increasing mental fatigue, preparation processes seemed to become less adequate and the number of errors increased. A clear poststimulus parietal negativity was observed on repetition trials, which reduced with time on task. This attention-related component was less pronounced in switch trials; instead, ERPs elicited in switch trials showed a clear frontal negativity. This negativity was also diminished by time on task. ERP differences between repetition and switch trials became smaller with increasing time on task. 相似文献
46.
Toshiie Sakata Masataka Fukushima Koichiro Tsutsui Koichi Arase Kazuma Fujimoto 《Physiology & behavior》1982,28(4):641-647
To test the possibility that theophylline induced circadian disappearance of food intake might depend upon rhythmic disruption of blood glucose, insulin and free fatty acids (FFA), theophylline was administered chronically. This markedly lengthened postprandial intermeal intervals during the dark, and induced approximately identical intermeal intervals and identical meal sizes in the light and dark periods. In contrast to the clear light-dark dependent oscillations of serum glucose, insulin and FFA in the controls, the theophyllinized rats lost circadian fluctuation of each of these three chemical substances. Further, theophyllinized rats, unlike controls, had no time-dependent fluctuation in the levels of these substances at ? 120, ?60 or ?15 min preceding the onset of the first meal before the dark. These findings, together with previous reports, explain the disappearance of nocturnal feeding rhythm in theophyllinized rats in terms of functional destruction of circadian regulation in the hypothalamus which modulate the production of chemical determinants of food intake. 相似文献
47.
Gaëlle Dzangué-Tchoupou Kuberaka Mariampillai Loïs Bolko Damien Amelin Wladimir Mauhin Aurélien Corneau Catherine Blanc Yves Allenbach Olivier Benveniste 《Autoimmunity reviews》2019,18(4):325-333
Background
Myositis is a heterogeneous group of muscular auto-immune diseases with clinical and pathological criteria that allow the classification of patients into different sub-groups. Inclusion body myositis is the most frequent myositis above fifty years of age. Diagnosing inclusion body myositis requires expertise and is challenging. Little is known concerning the pathogenic mechanisms of this disease in which conventional suppressive-immune therapies are inefficacious.Objectives
Our aim was to deepen our understanding of the immune mechanisms involved in inclusion body myositis and identify specific biomarkers.Methods
Using a panel of thirty-six markers and mass cytometry, we performed deep immune profiling of peripheral blood cells from inclusion body myositis patients and healthy donors, divided into two cohorts: test and validation cohorts. Potential biomarkers were compared to myositis controls (anti-Jo1-, anti-3-hydroxyl-3-methylglutaryl CoA reductase-, and anti-signal recognition particle-positive patients).Results
Unsupervised analyses revealed substantial changes only within CD8+ cells. We observed an increase in the frequency of CD8+ cells that expressed high levels of T-bet, and containing mainly both effector and terminally differentiated memory cells. The senescent marker CD57 was overexpressed in CD8+T-bet+ cells of inclusion body myositis patients. As expected, senescent CD8+T-bet+ CD57+ cells of both patients and healthy donors were CD28nullCD27nullCD127null. Surprisingly, non-senescent CD8+T-bet+ CD57- cells in inclusion body myositis patients expressed lower levels of CD28, CD27, and CD127, and expressed higher levels of CD38 and HLA-DR compared to healthy donors. Using classification and regression trees alongside receiver operating characteristics curves, we identified and validated a frequency of CD8+T-bet+ cells >51.5% as a diagnostic biomarker specific to inclusion body myositis, compared to myositis control patients, with a sensitivity of 94.4%, a specificity of 88.5%, and an area under the curve of 0.97.Conclusion
Using a panel of thirty-six markers by mass cytometry, we identify an activated cell population (CD8+T-bet+ CD57- CD28lowCD27lowCD127low CD38+ HLA-DR+) which could play a role in the physiopathology of inclusion body myositis, and identify CD8+T-bet+ cells as a predominant biomarker of this disease. 相似文献48.
用自行设计的踏车多指标心血管功能评价系统(E系统),对正常人,冠心病患者、心肌梗塞患者三组进行踏车运动前后Q—Tc变化及运动前后心血管功能评定。对静息时或运动后Q—Tc延长诊断冠心病价值及运动前后心血管功能变化规律的敏感性、特殊性分别进行对照和探讨。 相似文献
49.
Effects of sino-aortic denervation on spectral characteristics of blood pressure and pulse interval variability: a wide-band approach 总被引:3,自引:0,他引:3
Dr. M. Di Rienzo P. Castiglioni G. Parati G. Mancia A. Pedotti 《Medical & biological engineering & computing》1996,34(2):133-141
Sino-aortic denervation (SAD) is employed in cats to evaluate the baroreflex influence on blood pressure (BP) and pulse interval
(PI) spectral components from 0·00008 to 0·9 Hz as assessed by FFT wide-band spectra and their 1/f modelling; and the linear
coupling between BP and PI and between systolic and diastolic BP as assessed by coherence analysis. Specific procedures have
been developed to obtain an effective smoothing of spectra and coherence functions. SAD induced an increase in BP powers from
0·03 to 0·0006 Hz and a power reduction of most of the remaining BP components; a reduction of PI powers at all frequencies;
marked deviations of BP spectra from the 1/f trend; a reduction of the coherence between BP and PI from 0·12 to 0·5 Hz and
a coherence enhancement at lower frequencies. These findings indicate that the arterial baroreflex modulates both fast and
slow spectral components of BP and PI; homogeneously enhances PI fluctuations at all frequencies; produces differentiated
effects on BP fluctuations along the frequency axis; and at low frequencies exerts the buffering action on BP through strategies
which reduce the BP-PI linear link. 相似文献
50.
The P3(00) is an electrophysiological index of neural processing that varies with such stimulus parameters as interstimulus interval (ISI) and target probability, with a common view being that it reflects an endogenous form of memory update. Building on previous research, we argue that relations between P3 amplitude and both ISI and probability may be attributable to the target-to-target interval (TTI). Employing between-subject (Experiment 1; N = 24) and within-subject (Experiment 2; N = 10) designs, the present paper addresses this by testing subjects on a standard two-tone auditory oddball task as well as a one-tone task. In both studies, P3 amplitude increased and latency decreased linearly with TTI, and these relations were relatively unaffected by ISI or probability. This suggests that ISI and probability per se do not independently affect P3 amplitude, and that TTI offers a strong explanation of the reported relations between P3 amplitude and both ISI and probability. 相似文献