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81.
SRINIVASAN RAJARAMAN SRIDHAR RAMAKRISHNAN DAVID THORSLEY NANCY J. WESENSTEN THOMAS J. BALKIN JAQUES REIFMAN 《Journal of sleep research》2012,21(6):659-674
We have developed a new psychomotor vigilance test (PVT) metric for quantifying the effects of sleep loss on performance impairment. The new metric quantifies performance impairment by estimating the probability density of response times (RTs) in a PVT session, and then considering deviations of the density relative to that of a baseline‐session density. Results from a controlled laboratory study involving 12 healthy adults subjected to 85 h of extended wakefulness, followed by 12 h of recovery sleep, revealed that the group performance variability based on the new metric remained relatively uniform throughout wakefulness. In contrast, the variability of PVT lapses, mean RT, median RT and (to a lesser extent) mean speed showed strong time‐of‐day effects, with the PVT lapse variability changing with time of day depending on the selected threshold. Our analysis suggests that the new metric captures more effectively the homeostatic and circadian process underlying sleep regulation than the other metrics, both directly in terms of larger effect sizes (4–61% larger) and indirectly through improved fits to the two‐process model (9–67% larger coefficient of determination). Although the trend of the mean speed results followed those of the new metric, we found that mean speed yields significantly smaller (~50%) intersubject performance variance than the other metrics. Based on these findings, and that the new metric considers performance changes based on the entire set of responses relative to a baseline, we conclude that it provides a number of potential advantages over the traditional PVT metrics. 相似文献
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Importance of Ventricular Tachycardia Induction and Mapping for Patients Referred for Epicardial Ablation
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GREGORY WOO M.D. THOMAS BURKART M.D. WILLIAM MILES M.D. SHERRY SAXONHOUSE M.D. JAMIE CONTI M.D. 《Pacing and clinical electrophysiology : PACE》2010,33(2):246-247
An asymptomatic patient with a Teletronics Accufix atrial lead (Teletronics, Englewood, CO, USA) presented for an annual fluoroscopic examination. The examination revealed a retention wire fracture, which occurred 18 years after the initial implantation. Annual fluoroscopic examination of these leads should still be performed. (PACE 2010; 33:246–247) 相似文献
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MICHAEL ROBINSON THOMAS R. GUSTAD STEPHANIE D. GARNER CHELLA S. DAVID 《Parasite immunology》1995,17(5):237-243
A number of T cell hybridomas were produced to adult worm homogenate (AWH) antigen of the nematode parasite Heligmosomoides polygyrus. All of the hybridomas were of the H-2d haplotype and could potentially accept antigen in the context of either the Ad or Ed, H-2 molecules. Three types of antigen presentation were observed, with some of the T cell hybridomas accepting antigen in the context of the E and some in the context of the A molecule. A third type of hybridoma responded to antigen presented by paraformaldehyde fixed APC, but only when APCs were Epositive. These same hybridomas, were however, stimulated by A WH, when the antigen was presented by syngeneic but unfixed, E positive or E negative A PC. Therefore these data indicate that certain H. polygyrus-specfic T cell hybridomas can accept parasite antigen when presented in the context of either the H-2 A or E molecule, but the presentation of antigen by the two different MHC Class II molecules, can apparently utilize differing processing mechanisms., 相似文献
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HANS KOTTKAMP M.D. XU CHEN M.D. GERHARD HINDRICKS M.D. THOMAS WICHTER M.D. STEPHAN WILLEMS M.D. SINNIKA YLI-MÄYRY M.D. GÜNTER BREITHARDT M.D. MARTIN BORGGREFE M.D. 《Journal of cardiovascular electrophysiology》1996,7(3):206-210
Ablation with Temperature-Controlled 5-French Catheters. Introduction: In the present study, we assessed the feasibility of radiofrequency (RF) ablation of accessory pathways and AV nodal reentrant tachycardias with novel 5-French catheters with 4-mm tip electrodes using established mapping criteria and temperature-controlled power output control. Methods and Results: In this prospective study, 60 consecutive adult patients (mean age 36 ± 20 years) with accessory pathways (n = 37; 24 left-sided) or AV nodal reentrant tachycardia (n = 23) underwent RF catheter ablation. A 5-French catheter with a 4-mm tip electrode and an embedded thermistor was used for RF application. The surface of the tip electrodes was 26 mm2 compared to 38 mm2 of 7-French catheters with 4-mm tip electrodes from the same catheter series. Power output was automatically and continuously adjusted according to the preset catheter tip temperature of 60° to 70°C. Pulse duration was 90 seconds. For left-sided accessory pathways, the retrograde route via the femoral artery was used. After removing the 5-French sheaths, only 4 hours of bed rest were advised. For ablation of AV nodal reentrant tachycardia, the so-called slow pathway was targeted for ablation. Acute success was achieved in 34 (92%) of 37 patients with accessory pathways and 23 (100%) of 23 patients with AV nodal reentrant tachycardia. A mean of 3 ± 4 RF pulses (median 2 pulses; range 1 to 20 pulses) was applied. The mean fluoroscopy time was 26 ± 21 minutes. No complete AV block or other procedure-related complications were observed. Recurrences occurred in 2 patients with accessory pathways and in 2 patients with AV nodal reentrant tachycardia during a follow-up of 9 ± 4 months. Conclusions: Temperature-controlled RF ablation of accessory pathways and AV nodal reentrant tachycardia in adults using 5-French catheters is feasible, effective, and safe. Ablation with 5-French catheters might help to reduce the complication rate of catheter ablation techniques. 相似文献
90.
THOMAS D BOYER 《Journal of gastroenterology and hepatology》2004,19(S7):S191-S193
Abstract Hyponatremia develops spontaneously or following diuretic therapy in about one-third of patients with cirrhosis. The development of hyponatremia leads to fluid restriction which is unpopular with patients and limits the usefulness of diuretics. The principle factor that leads to hyponatremia in the cirrhotic is an increase in the non-osmotic release of arginine vasopressin (AVP) and subsequent impaired clearance of free water by the kidney. The development of vasopressin receptor antagonists and Κ-opioid agonists has led to trials examining their efficacy in the treatment of hyponatremia in cirrhosis. The vasopressin receptor antagonists have been shown to improve free water clearance and raise serum sodium in decompensated cirrhotics in short-term studies. The utility of these agents for the long-term management of hyponatremia and in preventing the development of hyponatremia associated with diuretic usage remains to be determined. 相似文献