Videofluoroscopic Evaluation of the Influence of a Gradually Reducing Femoral Radius on Joint Kinematics During Daily Activities in Total Knee Arthroplasty

BackgroundParadoxical anterior translation in midflexion is reduced in total knee arthroplasties (TKAs) with a gradually reducing femoral radius, when compared to a 2-radii design. This reduction has been shown in finite element model simulations, in vitro tests, intraoperatively, and recently also in vivo during a lunge and unloaded flexion-extension. However, TKA kinematics are task dependent and this reduction has not been tested for gait activities.MethodsThirty good outcome subjects (≥1 year postoperatively) with a unilateral cruciate-retaining TKA with a gradually reducing (n = 15) or dual (n = 15) femoral radius design were assessed during 5 complete cycles of level walking, stair descent (0.18-m steps), deep knee bend, and sitting down onto and standing up from a chair, using a moving fluoroscope (25 Hz, 1 ms shutter time). Kinematic data were extracted by 2D/3D image registration.ResultsTibiofemoral ranges of motion for flexion-extension, abduction-adduction, internal-external rotation, and anteroposterior (AP) translation were similar for both groups, whereas the pattern of AP translation-flexion-coupling differed. The subjects with the dual-radii design showed a sudden change in direction of AP translation around 30° of flexion, which was not present in the subjects with the gradually reducing femoral radius design.ConclusionThrough the unique ability of moving fluoroscopy, the present study confirmed that the gradually reducing femoral radii eliminated the paradoxical sudden anterior translation at 30° present in the dual-radii design in vivo during daily activities, including gait and stair descent.     

Prediction of skin sensitization potency using machine learning approaches

The replacement of animal use in testing for regulatory classification of skin sensitizers is a priority for US federal agencies that use data from such testing. Machine learning models that classify substances as sensitizers or non‐sensitizers without using animal data have been developed and evaluated. Because some regulatory agencies require that sensitizers be further classified into potency categories, we developed statistical models to predict skin sensitization potency for murine local lymph node assay (LLNA) and human outcomes. Input variables for our models included six physicochemical properties and data from three non‐animal test methods: direct peptide reactivity assay; human cell line activation test; and KeratinoSens™ assay. Models were built to predict three potency categories using four machine learning approaches and were validated using external test sets and leave‐one‐out cross‐validation. A one‐tiered strategy modeled all three categories of response together while a two‐tiered strategy modeled sensitizer/non‐sensitizer responses and then classified the sensitizers as strong or weak sensitizers. The two‐tiered model using the support vector machine with all assay and physicochemical data inputs provided the best performance, yielding accuracy of 88% for prediction of LLNA outcomes (120 substances) and 81% for prediction of human test outcomes (87 substances). The best one‐tiered model predicted LLNA outcomes with 78% accuracy and human outcomes with 75% accuracy. By comparison, the LLNA predicts human potency categories with 69% accuracy (60 of 87 substances correctly categorized). These results suggest that computational models using non‐animal methods may provide valuable information for assessing skin sensitization potency. Copyright © 2017 John Wiley & Sons, Ltd.     

Qualitative outcome assessment and research on chronic disease management in general practice. Highlights from a keynote lecture,EGPRN May 2011, Nice

At its 2011 conference in Nice, France, the European General Practice Research Network (EGPRN), considered the issue of Relevant Outcome Measures in General Practice Research into Chronic Diseases. This paper, which is adapted from a keynote lecture given during that conference, considers the role of qualitative outcome assessments in research. Such assessments have a great deal in common with the patient-centred approach of general practice as they can capture the overall state of a patient rather than capturing only certain aspects. Research suggests that patients can be categorized, based on qualitative outcome assessment, and over time might change category. This approach to assessment brings to our attention alternative ways of considering the future: future as currently being made or future as predictable, at least to some extent. Although general practice needs the evidence from research that predicts the future, it also needs to engage in research that seeks to understand patients as they make their future, and to understand the impact of clinical interventions on this process.     

厦门市手足口病流行特征分析及发病趋势预测方法研究

目的研究厦门市手足口病的流行特征并探讨季节性时间序列(seasonal autoregressive integrated moving average,SARIMA)模型拟合厦门市手足口病发病趋势预测的可行性。方法选取2011—2013年6家医院报告的手足口病10 540例,利用SPSS19.0对厦门市手足口病的发病情况进行流行病学分析,通过取自然对数、差分等方法对手足口病月发病数序列进行平稳化,然后进行模型参数的估计、检验,最优模型的筛选,最后进行预测分析。计量资料采用χ2检验,P0.05为差异有统计学意义。结果 2011—2013年厦门市手足口病的年平均发病率为97.37/10万,4—7月和9月有两个发病高峰,病例主要分布于5岁以下儿童,占所有病例数的93.85%;病原构成以其他肠道病毒为主,占42.9%,其次为肠道病毒71型(enteriovirus 71,EV71)占39.7%,柯萨奇病毒A6(coxsackie virus A6,Cox A6)仅占17.3%;SARIMA(0,1,0)(1,1,0)12较好地拟合了厦门市手足口病的月发病数据,预测效果良好。结论厦门市手足口病的发病率较高,可以用SARIMA模型进行短期预测,进而指导各项防控措施。     

Cellular senescence determines endothelial cell damage induced by uremia

Renal dysfunction is closely associated with endothelial damage leading to cardiovascular disease. However, the extent to which endothelial damage induced by uremia is modulated by aging is poorly known. Aging can render endothelial cells more susceptible to apoptosis through an oxidative stress-dependent pathway. We examined whether senescence-associated to oxidative stress determines the injury induced by the uremia in endothelial cells.