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B19 parvovirus is the etiologic agent of fifth disease and transient aplastic crisis. In natural infections, B19 antigen and DNA have been detected in sera early in the course of aplastic crisis and only rarely in fifth disease. We have found B19 DNA in circulating cells of infected patients by DNA dot blot with a virus-specific probe: in four of four sickle cell patients with aplastic crisis, in one asymptomatic sibling, and in one normal adult with fifth disease. Only two of the sera showed B19 DNA. High-molecular weight intermediate forms were detected by Southern analysis of DNA extracted from cells, thus indicating active replication of virus in cells rather than passive adsorption to their surface membranes. Separation of cells into high- and low-density fractions resulted in a concentration of the virus DNA in the granulocytic fraction. 相似文献
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Ping Jia Charulatha Ramanathan Raja N Ghanem Kyungmoo Ryu Niraj Varma Yoram Rudy 《Heart rhythm》2006,3(3):296-310
BACKGROUND: Cardiac resynchronization therapy (CRT) for congestive heart failure patients with delayed left ventricular (LV) conduction is clinically beneficial in approximately 70% of patients. Unresolved issues include patient selection, lead placement, and efficacy of LV pacing alone. Being an electrical approach, detailed electrical information during CRT is critical to resolving these issues. However, electrical data from patients have been limited because of the requirement for invasive mapping. OBJECTIVES: The purpose of this study was to provide observations and insights on the variable electrophysiologic responses of the heart to CRT using electrocardiographic imaging (ECGI). METHODS: ECGI is a novel modality for noninvasive epicardial mapping. ECGI was conducted in eight patients undergoing CRT during native rhythm and various pacing modes. RESULTS: In native rhythm (six patients), ventricular activation was heterogeneous, with latest activation in the lateral LV base in three patients and in the anterolateral, midlateral, or inferior LV in the remainder of patients. Anterior LV was susceptible to block and slow conduction. Right ventricular pacing improved electrical synchrony in two of six patients. LV pacing in three of four patients involved fusion with intrinsic excitation resulting in electrical resynchronization similar to biventricular pacing. Although generally electrical synchrony improved significantly with biventricular pacing, it was not always accompanied by clinical benefit. CONCLUSION: Results suggest that (1) when accompanied by fusion, LV pacing alone can be as effective as biventricular pacing for electrical resynchronization; (2) right ventricular pacing is not effective for resynchronization; and (3) efficacy of CRT depends strongly on the patient-specific electrophysiologic substrate. 相似文献
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Jin-Yun Liao Taylor
W. Smith Raja R. Pandey Xiaoqing He Charles C. Chusuei Yangchuan Xing 《RSC advances》2018,8(16):8929
Na2Ti6O13 (NTO) has recently been reported for lithium ion storage and showed very promising results. In this work, we report substantially enhanced rate capability in NTO nanowires by Ti(iii) self-doping and carbon-coating. Ti(iii) doping and carbon coating were found to work in synergy to increase the electrochemical performances of the material. For 300 cycles at 1C (1C = 200 mA g−1) the charge capacity of the electrode is 206 mA h g−1, much higher than that (89 mA h g−1) of the pristine NTO electrode. For 500 cycles at 5C the electrode can still deliver a charge capacity of 180.5 mA h g−1 with a high coulombic efficiency of 99%. At 20C the capacity of the electrode is 2.6 times that of the pristine NTO. These results clearly demonstrate that the Ti(iii) self-doping and uniform carbon coating significantly enhanced the kinetic processes in the NTO nanowire crystal, making it possible for fast charge and discharge in Li-ion batteries.Ti3+ self-doping and carbon-coating are efficient approaches to simultaneously improve the rate capability and cyclability of Na2Ti6O13 nanowires for lithium storage. 相似文献