Predicting the outcome of transcatheter mitral valve implantation using image-based computational models

BackgroundThe appropriate placement and size selection of mitral prostheses in transcatheter mitral valve implantation (TMVI) is critical, as encroachment on the left ventricular outflow tract (LVOT) may lead to flow obstruction. Recent advances in computed tomography (CT) can be employed for pre-procedural planning of mitral prosthetic valve placement. This study aims to develop patient-specific computational fluid dynamics models of the left ventricle (LV) in the presence of a mitral valve prosthesis to investigate blood flow and LVOT pressure gradient during systole.MethodsPatient-specific computational fluid dynamics simulations of TMVI with varied cardiac anatomy and insertion angles were performed (n = 30). Wide-volume full cycle cardiovascular CT images prior to TMVI were used as source anatomical data (n = 6 patients). Blood movement was governed by Navier-Stokes equations and the LV endocardial wall deformation was derived from each patient's CT images.ResultsThe computed pressure gradients in the presence of the mitral prosthesis compared well with clinically measured gradients. Analysis of the effects of prosthetic valve angulation, aorto-mitral annular angle, ejection fraction, LV size and new LVOT area (neo-LVOT) after TMVI in silico revealed that the neo-LVOT area (p < 0.001) was the most significant factor affecting LVOT pressure gradient. Angulation of the mitral valve can substantially mitigate LVOT gradient.ConclusionsComputational fluid dynamics simulation is a promising method to aid in pre-TMVI planning and understanding the factors underlying LVOT obstruction.     

Computer-aided design of dry powder inhalers using computational fluid dynamics to assess performance

Dry powder inhalers (DPIs) are gaining popularity for the delivery of drugs. A cost effective and efficient delivery device is necessary. Developing new DPIs by modifying an existing device may be the simplest way to improve the performance of the devices. The aim of this research was to produce a new DPIs using computational fluid dynamics (CFD). The new DPIs took advantages of the Cyclohaler® and the Rotahaler®. We chose a combination of the capsule chamber of the Cyclohaler® and the mouthpiece and grid of the Rotahaler®. Computer-aided design models of the devices were created and evaluated using CFD. Prototype models were created and tested with the DPI dispersion experiments. The proposed model 3 device had a high turbulence with a good degree of deagglomeration in the CFD and the experiment data. The %fine particle fraction (FPF) was around 50% at 60?L/min. The mass median aerodynamic diameter was around 2.8–4?μm. The FPF were strongly correlated to the CFD-predicted turbulence and the mechanical impaction parameters. The drug retention in the capsule was only 5–7%. In summary, a simple modification of the Cyclohaler® and Rotahaler® could produce a better performing inhaler using the CFD-assisted design.     

Correlation between magnetic resonance imaging characteristics and BRAF alteration status in individuals with optic pathway/hypothalamic pilocytic astrocytomas

Background and purposeMost individuals with optic pathway/hypothalamic pilocytic astrocytoma (OPHPA) harbor either the BRAF V600E mutation or KIAA1549-BRAF fusion (K-B). This study aimed to investigate the imaging characteristics of OPHPA in relation to BRAF alteration status.Materials and methodsSeven cases of OPHPA harboring either the BRAF V600E mutation or K-B fusion were included in the study. Preoperative magnetic resonance imaging (MRI) was assessed for degree of T2 hyperintensity on T2-weighted images (T2WI) and the ratio of nonenhancing T2 or fluid-attenuated inversion recovery (FLAIR) hyperintense area to the contrast enhanced area (CE) on gadolinium-enhanced-T1 weighted images (T2/FLAIR-CE mismatch). The T2 signal intensity was normalized to cerebrospinal fluid (T2/CSF) for both the V600E and K-B group and compared. T2/FLAIR-CE mismatch was assessed by calculating the proportion of the tumor volume of nonenhancing high T2 signal intensity to the whole lesion (nonenhancing and enhancing components).ResultsFour and three cases of OPHPA harboring the BRAF V600E mutation and K-B, respectively, were analyzed. The T2/CSF value was higher in the K-B group than in the V600E group. Moreover, the V600E group had a larger T2/FLAIR-CE mismatch than the K-B group.ConclusionsThe BRAF alteration status in individuals with OPHPA was associated with preoperative MRI by focusing on T2 signal intensity and T2/FLAIR-CE mismatch. The BRAF V600E mutation was associated with a lower T2/CSF value and larger T2/FLAIR-CE mismatch, whereas K-B fusion was associated with a higher T2/CSF value and smaller T2/FLAIR-CE mismatch.     

运动饮料促进运动后体液恢复的应用研究进展

良好的水合状态对运动人群的运动能力及其认知功能至关重要。运动后快速恢复体液有利于防止脱水,维持体液平衡,促进疲劳恢复,增强运动能力。运动饮料作为强有力的运动营养补充剂,其成分和配方设计不同,实际效果也有所差异。本文对目前应用于运动后体液恢复的运动饮料的类型、成分、效果及机制进行综述,以期为运动饮料的研发提供线索。     

汉代以来著名医家治疗痰饮用药规律的数据挖掘研究＊

目的 探讨汉代以来著名医家治疗痰饮的方剂用药与组方规律，以期对痰饮临床治疗及中药新药研发提供参考。方法 收集整理汉代以来著名医家的痰饮论述与医案共涉及208首方剂，录入中医传承辅助系统（V2.5），采用改进的互信息法、关联规则、复杂系统熵聚类、无监督的熵层次聚类，进行痰饮数据库单药、对药、角药的统计、关联规则分析、提取核心组合与新方发现，进行数据挖掘研究。结果 最常见单药是半夏（117次，占56.25%）；最常见对药是半夏-茯苓（62次，占29.81%）；最常见角药是半夏-陈皮-茯苓（33次，占15.87%）；关联度最高的药物组合是生姜 + 茯苓→半夏（置信度为0.8636）；得到18组3味药的核心组合，核心药物为：半夏、茯苓、陈皮、生姜、甘草、桂枝等；得到治疗痰饮9个新候选处方。结论 提示今后痰饮治疗及新药研发时，单药、对药、角药优先考虑：半夏、陈皮、茯苓；配伍优先考虑：生姜、茯苓配伍半夏；核心方剂优先考虑：杏仁-麻黄-桑白皮；新候选处方优先考虑：杏仁、麻黄、桑白皮、阿胶、款冬花。     

补肾凉血安胎法治疗肾虚血热型先兆流产合并官腔积液临床研究

目的:研究补肾凉血安胎法治疗肾虚血热型先兆流产合并宫腔积液的效果。方法:选择肾虚血热型先兆流产合并宫腔积液患者160例,按随机数字表法分为对照组和观察组各80例。对照组给予黄体酮联合酚磺乙胺治疗,观察组采用补肾凉血安胎法治疗,连续治疗2周。观察2组临床疗效,比较2组孕酮(P)、雌二醇(E2)、人绒毛膜促性腺激素(HCG),以及中医症候评分。结果:观察组总有效率为85.00%,高于对照组70.00%(P<0.05)。治疗前,2组P、HCG、E2水平比较,差异无统计学意义(P>0.05)。治疗后,2组P、HCG、E2水平较治疗前升高(P<0.05),且观察组P、HCG、E2水平高于对照组(P<0.05)。治疗前,2组各项中医症状评分比较,差异无统计学意义(P>0.05)。治疗后,2组各项中医症状评分较治疗前降低(P<0.05),且观察组各项中医症状评分低于对照组(P<0.05)。结论:采用补肾凉血安胎汤治疗肾虚血热型先兆流产合并宫腔积液患者,不仅能改善患者血液指标,有利于保胎,还能促进宫腔积液的吸收,效果显著,值得临床应用。     

Light sheet fluorescence microscopy of optically cleared brains for studying the glymphatic system

Fluid transport in the perivascular space by the glia-lymphatic (glymphatic) system is important for the removal of solutes from the brain parenchyma, including peptides such as amyloid-beta which are implicated in the pathogenesis of Alzheimer’s disease. The glymphatic system is highly active in the sleep state and under the influence of certain of anaesthetics, while it is suppressed in the awake state and by other anaesthetics. Here we investigated whether light sheet fluorescence microscopy of whole optically cleared murine brains was capable of detecting glymphatic differences in sleep- and awake-mimicking anaesthesia, respectively. Using light-sheet imaging of whole brains, we found anaesthetic-dependent cerebrospinal fluid (CSF) influx differences, including reduced tracer influx along tertiary branches of the middle cerebral artery and reduced influx along dorsal and anterior penetrating arterioles, in the awake-mimicking anaesthesia. This study establishes that light sheet microscopy of optically cleared brains is feasible for quantitative analyses and can provide images of the entire glymphatic system in whole brains.     

Outcome measures from experimental traumatic brain injury in male rats vary with the complete temporal biomechanical profile of the injury event

Millions suffer a traumatic brain injury (TBI) each year wherein the outcomes associated with injury can vary greatly between individuals. This study postulates that variations in each biomechanical parameter of a head trauma lead to differences in histological and behavioral outcome measures that should be considered collectively in assessing injury. While trauma severity typically scales with the magnitude of injury, much less is known about the effects of rate and duration of the mechanical insult. In this study, a newly developed voice-coil fluid percussion injury system was used to investigate the effects of injury rate and fluid percussion impulse on a collection of post-injury outcomes in male rats. Collectively the data suggest a potential shift in the specificity and progression of neuronal injury and function rather than a general scaling of injury severity. While a faster, shorter fluid percussion first presents as a mild TBI, neuronal loss and some behavioral tasks were similar among the slower and faster fluid percussion injuries. This study concludes that the sequelae of neuronal degeneration and behavioral outcomes are related to the complete temporal profile of the fluid percussion and do not scale only with peak pressure.