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121.
ULRICH LOTZE M.D. † SVEN FISCHER M.D. ‡ § TILL HÖFS M.D. § JOHANNES LIEBETRAU M.D. † WOLFGANG FETTIN M.D. ¶ JÖRG SCHEINER M.Sc. ANDREAS LANG M.D. †† for the German IsoFlex Lead Registry Investigators 《Pacing and clinical electrophysiology : PACE》2009,32(8):1050-1055
Background: Bipolar low polarization electrodes are recommended for a regular AutoCapture™ (St. Jude Medical, Inc., Sylmar, CA, USA) function in order to effectively detect the evoked response (ER) signal. The objective of this national multicenter registry was to evaluate the electrical performance and the AutoCapture™ characteristics of the bipolar ventricular pacing lead IsoFlex S, model 1636T or 1646T (St. Jude Medical), in combination with single- and dual-chamber pacemakers.
Methods: Ventricular pacing and sensing thresholds, lead impedance, ER amplitude, and polarization signals were measured at discharge and routine follow-up visits after 1, 3, 6, 9, and 12 months. AutoCapture™ activation was recommended based on the results of the ER sensitivity test.
Results: Of the 252 patients initially included, 109 (43%) have completed the follow-up. The mean ventricular pacing threshold was 0.43 ± 0.19 V at discharge and 0.68 ± 0.32 V at 12 months postimplant. The values for the ventricular sensing threshold were between 9.51 ± 4.12 and 9.99 ± 4.09 mV at discharge and at the 12-month follow-up. The unipolar lead impedance decreased from 533 ± 94 to 476 ± 73 ohms during the follow-up. The mean ER amplitude was 16.47 ± 6.70 mV at discharge and 17.42 ± 7.43 mV after 12 months, and the corresponding mean polarization signals were 0.59 ± 1.00 and 0.74 ± 1.24 mV, respectively. AutoCapture™ activation was recommended in at least 95% of the patients investigated over the 12-month follow-up.
Conclusion: The bipolar ventricular pacing lead IsoFlex S 1636/1646T shows a good electrical performance and is mostly compatible with the AutoCapture™ algorithm. 相似文献
Methods: Ventricular pacing and sensing thresholds, lead impedance, ER amplitude, and polarization signals were measured at discharge and routine follow-up visits after 1, 3, 6, 9, and 12 months. AutoCapture™ activation was recommended based on the results of the ER sensitivity test.
Results: Of the 252 patients initially included, 109 (43%) have completed the follow-up. The mean ventricular pacing threshold was 0.43 ± 0.19 V at discharge and 0.68 ± 0.32 V at 12 months postimplant. The values for the ventricular sensing threshold were between 9.51 ± 4.12 and 9.99 ± 4.09 mV at discharge and at the 12-month follow-up. The unipolar lead impedance decreased from 533 ± 94 to 476 ± 73 ohms during the follow-up. The mean ER amplitude was 16.47 ± 6.70 mV at discharge and 17.42 ± 7.43 mV after 12 months, and the corresponding mean polarization signals were 0.59 ± 1.00 and 0.74 ± 1.24 mV, respectively. AutoCapture™ activation was recommended in at least 95% of the patients investigated over the 12-month follow-up.
Conclusion: The bipolar ventricular pacing lead IsoFlex S 1636/1646T shows a good electrical performance and is mostly compatible with the AutoCapture™ algorithm. 相似文献
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三尖杉树皮粗提取物中的一个新生物碱—高三尖杉酯碱酰胺(homoharringtonamide)的结构,经质谱—质谱分析,初步建议为16。类似的酰胺类生物碱,例如三尖杉碱酰胺(cephalotaxamide,6)、11-羟基三尖杉碱酰胺(11-hydroxycephalotaxamide,9)、三尖杉酯碱酰胺(harfingtonamide,14)或异三尖杉酯碱酰胺(isoharringtonamide,15)也可能存在,后三者(9,14,15)尚未见报道。 相似文献
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The evolution of highly polymorphic gene loci is following routes that cannot be extrapolated from the existing knowledge of single copy genes. In addition, interpreting the evolution of the most polymorphic loci in vertebrates requires a plethora of data from different taxa. We evaluate here the rules for the evolution of Major Histocompatibility Complex (MHC-)DRB genes recently established in humans and other primates on the basis of sequences from several artiodactyl species. MHC genes encode essential molecules for self/altered-self/non-self discrimination in the interaction of the organism with its environment. The necessity to effectively present various different antigens to immunocompetent cells causes positive selection pressure on the variability of these genes in the population. Artiodactyls represent the third mammalian order in which this phenomenon was evidenced independently. A further incentive to investigate also the surroundings of MHC-DRB loci was the presence of a particular repetitive sequence stretch in the vicinity of the polymorphic exon - in addition to the evolutionarily old alleles, ancient polymorphisms and the mechanisms for their generation and/or maintenance. Besides their utility for indirect gene diagnosis (MHC-DRB typing), the closely linked stretches of simple repetitive DNA in the neighborhood of the highly polymorphic MHC-DRB genes are also interesting remains of the evolutionary history. Evolutionary developmenl is different in genetically inert intron-ic DNA compared to the exonic counterparts, despite their close vicinity. The persistence of these simple repeats over nearly 100 million years in one location preserving the same basic motif structure is startling. Indirect evidence is weighed that biological meaning should be considered for these elements. The combined analysis of the polymorphic DRB genes and the (highly variable but persistent) simple repeat stretches deepen our understanding of the complexities within a unique genomic compartment encoding essential molecules for self/non-self dif-ferentiation in the interaction of the organism with its environment. 相似文献
127.
Thirty-three patients with a variety of disorders of the thoracic aorta (aneurysm, dissection, Marfan syndrome, coarctation/pseudocoarctation, L-transposition, and Takayasu disease) were evaluated with magnetic resonance (MR) imaging. MR imaging delineated the presence and extent of thoracic aortic aneurysms and showed the relationship of the aneurysm to arch vessels; it also demonstrated intimal flaps and individual lumina in types A and B aortic dissection. Dilation of the ascending aorta in Marfan syndrome and focal narrowing of the aorta in coarctation were well visualized. The anteroposterior and side-to-side relationships of the aorta and pulmonary artery in L-transposition were demonstrated, as were aortic wall thickening and branch vessel narrowing in Takayasu arteritis. Initial experience suggests that MR imaging may provide a noninvasive method for evaluating thoracic aortic disease. Limitations include inferior spatial resolution, occasional difficulty in imaging the entire region of interest in one section, lack of signal from calcifications, and inability to monitor critically ill patients. 相似文献
128.
NM Gude RG King SP Brennecke 《Clinical and experimental pharmacology & physiology》1998,25(9):706-711
1. Interactions between autacoids may play important roles in the regulation of blood flow in the foetal placenta. In order to investigate this aspect of placental haemodynamics, human normal-term placentae were perfused in vitro and the responses of the foetal vessels to various combinations of vasoactive agents were determined. 2. Vasoconstriction responses to 5-hydroxytryptamine (5-HT) were potentiated in the presence of endothelin-1 (ET-1), the thromboxane A2-mimetic U46619 and a nitric oxide synthase inhibitor, N-nitro-l -arginine (NOLA), but not in the presence of angiotensin II. 3. N-Nitro-l -arginine caused vasoconstriction of the perfused placenta and indomethacin attenuated this effect and blocked the potentiation of the 5-HT response by NOLA. 4. Indomethacin did not affect ET-1-induced pressure increases and infusion of U46619 had no effect on release of ET-Iike immunoreactivity into the foetal placental circulation. 5. The present study provides evidence of interactions between several autacoids in human perfused placentae in vitro. These interactions may play important roles in foetal placental haemodynamics in normal or pathological situations. 相似文献
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130.
ANNETTE G. BECK-SICKINGER GERD SCHNORRENBERG J
RG METZGER GÜNTHER JUNG 《Chemical biology & drug design》1991,38(1):25-31
Several arginine-rich peptides containing the C-terminus of neuropeptide Y (NPY) were prepared by solid phase peptide synthesis using Fmoc chemistry and cleaved from the resin with trifluoroacetic acid (TFA). The products were characterized by fast atom bombardment-MS, LC-thermospray-MS, ion spray-MS/MS, and Edman degradation. The side products could be identified as peptides with sulfonated arginine residues resulting from an unexpected cleavage of Mtr or Pmc protecting groups. The degree of sulfonation depended on the choice and composition of the cleavage solution. Several scavenger mixtures were used and a mixture of thioanisole/thiocresol was found to be the most efficient for suppressing sulfonation. Furthermore treatment with the enzyme arylsulfate-sulfohydrolase desulfonated the peptides yielding the correct sequence. 相似文献