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排序方式: 共有196条查询结果,搜索用时 15 毫秒
1.
Differences in right ventricular morphology,not function,indicate the nature of increased afterload in pulmonary hypertensive subjects with normal left ventricular function 下载免费PDF全文
2.
Robin T Bigelow Yevgeniy R Semenov Eric Anson Sascha du Lac Luigi Ferrucci Yuri Agrawal 《Journal of the Association for Research in Otolaryngology》2016,17(5):433-440
Animal studies have demonstrated that experimentally induced vestibular ablation leads to a decrease in bone mineral density, through mechanisms mediated by the sympathetic nervous system. Loss of bone mineral density is a common and potentially morbid condition that occurs with aging, and we sought to investigate whether vestibular loss is associated with low bone mineral density in older adults. We evaluated this question in a cross-sectional analysis of data from the Baltimore Longitudinal Study of Aging (BLSA), a large, prospective cohort study managed by the National Institute on Aging (N = 389). Vestibular function was assessed with cervical vestibular evoked myogenic potentials (cVEMPs), a measure of saccular function. Bone mineral density was assessed using dual-energy X-ray absorptiometry (DEXA). In two-way t test analysis, we observed that individuals with reduced vestibular physiologic function had significantly lower bone mineral density. In adjusted multivariate linear regression analyses, we observed that older individuals with reduced vestibular physiologic function had significantly lower bone mineral density, specifically in weight-bearing hip and lower extremity bones. These results suggest that the vestibular system may contribute to bone homeostasis in older adults, notably of the weight-bearing hip bones at greatest risk of osteoporotic fracture. Further longitudinal analysis of vestibular function and bone mineral density in humans is needed to characterize this relationship and investigate the potential confounding effect of physical activity. 相似文献
3.
The precise structure of the HPV16 major neutralizing epitope recognized by H16.V5 monoclonal antibody is unknown. This paper describes a novel polyacrylamide gel electrophoresis (PAGE) for separation of HPV virus-like particles (VLPs) using cetyltrimethylammonium chloride (CTAC) as a solubilizing agent. CTAC PAGE employs KOH/CH3CO2H (pH 4-5.4) as a buffer system, K+ as the leading ion and 3-aminopropionic acid as a trailing ion. The unique characteristics of a cationic electrophoresis system allow separation of VLPs without heat denaturation. HPV VLP gel migration patterns were dependent on pre-treatment conditions: (1) thiol-agent reduction alone resulted in a 174 kDa band (interpreted as a L1 trimer), a 53 kDa band (size of the L1 monomer), as well as higher Mr aggregates consistent with a pentamer size; (2) both heat denaturation and thiol-agent reduction resulted in a 53 kDa band. Western blot analysis showed that the 174 kDa L1 trimer was strongly immunoreactive with H16.V5 and HPV16 VLP ELISA positive human sera, whereas no reactivity was seen with the monomeric L1 unit. These data suggest that a structure consistent with the migration pattern of a L1 trimer contains the major neutralizing epitope recognized by the H16.V5 MAb and human sera. 相似文献
4.
Martine Hoogendoorn Talitha L. Feenstra Yumi Asukai Sixten Borg Ryan N. Hansen Sven-Arne Jansson Yevgeniy Samyshkin Margarethe Wacker Andrew H. Briggs Adam Lloyd Sean D. Sullivan Maureen P.M.H. Rutten-van Mölken 《Value in health》2014,17(5):525-536
ObjectivesTo compare different chronic obstructive pulmonary disease (COPD) cost-effectiveness models with respect to structure and input parameters and to cross-validate the models by running the same hypothetical treatment scenarios.MethodsCOPD modeling groups simulated four hypothetical interventions with their model and compared the results with a reference scenario of no intervention. The four interventions modeled assumed 1) 20% reduction in decline in lung function, 2) 25% reduction in exacerbation frequency, 3) 10% reduction in all-cause mortality, and 4) all these effects combined. The interventions were simulated for a 5-year and lifetime horizon with standardization, if possible, for sex, age, COPD severity, smoking status, exacerbation frequencies, mortality due to other causes, utilities, costs, and discount rates. Furthermore, uncertainty around the outcomes of intervention four was compared.ResultsSeven out of nine contacted COPD modeling groups agreed to participate. The 5-year incremental cost-effectiveness ratios (ICERs) for the most comprehensive intervention, intervention four, was €17,000/quality-adjusted life-year (QALY) for two models, €25,000 to €28,000/QALY for three models, and €47,000/QALY for the remaining two models. Differences in the ICERs could mainly be explained by differences in input values for disease progression, exacerbation-related mortality, and all-cause mortality, with high input values resulting in low ICERs and vice versa. Lifetime results were mainly affected by the input values for mortality. The probability of intervention four to be cost-effective at a willingness-to-pay value of €50,000/QALY was 90% to 100% for five models and about 70% and 50% for the other two models, respectively.ConclusionsMortality was the most important factor determining the differences in cost-effectiveness outcomes between models. 相似文献
5.
Yevgeniy Samyshkin Robert W. Kotchie Ann-Christin Mörk Andrew H. Briggs Eric D. Bateman 《The European journal of health economics》2014,15(1):69-82
Objective
To estimate the cost-effectiveness of adding a selective phosphodiesterase-4 inhibitor, roflumilast, to a long-acting bronchodilator therapy (LABA) for the treatment of patients with severe-to-very severe chronic obstructive pulmonary disease (COPD) associated with chronic bronchitis with a history of frequent exacerbations from the UK payer perspective.Methods
A Markov model was developed to predict the lifetime cost and outcomes [exacerbations rates, life expectancy, and quality-adjusted life years (QALY)] in patients treated with roflumilast, which showed a reduction in the exacerbation rates and lung function improvement in a pooled analysis from two clinical trials, M2-124 and M2-125. Sensitivity analyses were conducted to explore the impact of uncertainties on the cost-effectiveness.Results
The addition of roflumilast to concomitant LABA reduced the number of exacerbations from 15.6 to 12.7 [2.9 (95 % CI 0.88–4.92) exacerbations avoided] and increased QALYs from 5.45 to 5.61 [0.16 (95 % CI 0.02–0.31) QALYs gained], at an incremental cost of £3,197 (95 % CI £2,135–£4,253). Cost in LABA alone and LABA + roflumilast were £16,161 and £19,358 respectively. The incremental cost-effectiveness ratios in the base case were £19,505 (95 % CI £364–£38,646) per quality-adjusted life-year gained and 18,219 (95 % CI £12,697–£49,135) per life-year gained. Sensitivity analyses suggest that among the main determinants of cost-effectiveness are the reduction of exacerbations and the case fatality rate due to hospital-treated exacerbations. Probabilistic sensitivity analysis suggests that the probability of roflumilast being cost-effective is 82 % at willingness-to-pay £30,000 per QALY.Conclusions
The addition of roflumilast to LABA in the treatment of patients with severe-to-very severe COPD reduces the rate of exacerbations and can be cost-effective in the UK setting. 相似文献6.
Yevgeniy B. Sirotin Elizabeth M. C. Hillman Clemence Bordier Aniruddha Das 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(43):18390-18395
In functional brain imaging there is controversy over which hemodynamic signal best represents neural activity. Intrinsic signal optical imaging (ISOI) suggests that the best signal is the early darkening observed at wavelengths absorbed preferentially by deoxyhemoglobin (HbR). It is assumed that this darkening or “initial dip” reports local conversion of oxyhemoglobin (HbO) to HbR, i.e., oxygen consumption caused by local neural activity, thus giving the most specific measure of such activity. The blood volume signal, by contrast, is believed to be more delayed and less specific. Here, we used multiwavelength ISOI to simultaneously map oxygenation and blood volume [i.e., total hemoglobin (HbT)] in primary visual cortex (V1) of the alert macaque. We found that the hemodynamic “point spread,” i.e., impulse response to a minimal visual stimulus, was as rapid and retinotopically specific when imaged by using blood volume as when using the initial dip. Quantitative separation of the imaged signal into HbR, HbO, and HbT showed, moreover, that the initial dip was dominated by a fast local increase in HbT, with no increase in HbR. We found only a delayed HbR decrease that was broader in retinotopic spread than HbO or HbT. Further, we show that the multiphasic time course of typical ISOI signals and the strength of the initial dip may reflect the temporal interplay of monophasic HbO, HbR, and HbT signals. Characterizing the hemodynamic response is important for understanding neurovascular coupling and elucidating the physiological basis of imaging techniques such as fMRI. 相似文献
7.
8.
Gallia GL Haque R Garonzik I Witham TF Khavkin YA Wolinsky JP Suk I Gokaslan ZL 《Journal of neurosurgery. Spine》2005,3(6):501-506
Although radical resection prolongs the disease-free survival period, surgical management of primary sacral tumors is challenging because of their location and often large size. Moreover, in cases of lesions for which a radical resection necessitates total sacrectomy, reconstruction is required. The authors have previously described a modified Galveston technique in which a liaison between the spine and pelvis is achieved using lumbar pedicle screws and Galveston rods embedded into the ilia; additionally, a transiliac bar reestablishes the pelvic ring. Although this reconstruction technique achieves stabilization, several biomechanical limitations exist. In the present report the authors present the case of a patient who underwent spinal pelvic reconstruction after a total sacrectomy was performed to remove a giant sacral chordoma. They describe a novel spinal pelvic reconstruction technique that addresses some of the biomechanical limitations. 相似文献
9.
10.
An agarose-based microfluidic platform with a gradient buffer for 3D chemotaxis studies 总被引:1,自引:0,他引:1
Ulrike Haessler Yevgeniy Kalinin Melody A. Swartz Mingming Wu 《Biomedical microdevices》2009,11(4):827-835
The current state-of-art in 3D microfluidic chemotaxis device (μFCD) is limited by the inherent coupling of the fluid flow
and chemical concentration gradients. Here, we present an agarose-based 3D μFCD that decouples these two important parameters,
in that the flow control channels are separated from the cell compartment by an agarose gel wall. This decoupling is enabled
by the transport property of the agarose gel, which—in contrast to the conventional microfabrication material such as polydimethylsiloxane
(PDMS)—provides an adequate physical barrier for convective fluid flow while at the same time readily allowing protein diffusion.
We demonstrate that in this device, a gradient can be pre-established in an agarose layer above the cell compartment (a gradient
buffer) before adding the 3D cell-containing matrix, and the dextran (10 kDa) concentration gradients can be re-established
within 10 min across the cell-containing matrix and remain stable indefinitely. We successfully quantified the chemotactic
response of murine dendritic cells to a gradient of CCL19, an 8.8 kDa lymphoid chemokine, within a type I collagen matrix.
This model system is easy to set up, highly reproducible, and will benefit research on 3D chemoinvasion studies, for example
with cancer cells or immune cells. Because of its gradient buffering capacity, it is particularly suitable for studying rapidly
migrating cells like mature dendritic cells and neutrophils.
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Ulrike Haessler and Yevgeniy Kalinin have equal contribution. 相似文献