Efficient high‐throughput biological process characterization: Definitive screening design with the Ambr250 bioreactor system

The burgeoning pipeline for new biologic drugs has increased the need for high‐throughput process characterization to efficiently use process development resources. Breakthroughs in highly automated and parallelized upstream process development have led to technologies such as the 250‐mL automated mini bioreactor (ambr250?) system. Furthermore, developments in modern design of experiments (DoE) have promoted the use of definitive screening design (DSD) as an efficient method to combine factor screening and characterization. Here we utilize the 24‐bioreactor ambr250? system with 10‐factor DSD to demonstrate a systematic experimental workflow to efficiently characterize an Escherichia coli (E. coli) fermentation process for recombinant protein production. The generated process model is further validated by laboratory‐scale experiments and shows how the strategy is useful for quality by design (QbD) approaches to control strategies for late‐stage characterization. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1388–1395, 2015     

A Bioeconomic Model of a Multi-site Fishery with Nonlinear Demand Function: Number of Sites Optimizing the Total Catch

We present a mathematical model of a fishery on several sites with a variable price. The model takes into account the evolution during the time of the resource, fish and boat movement between the different sites, fishing effort and price that varies with respect to supply and demand. We suppose that the movements of the boats and resource as well as the variation of the price go on at a fast time scale. We use methods of aggregation of variables in order to reduce the number of variables and we derive a reduced model governing two global variables, respectively the biomass of the resource and the fishing effort of the whole fishery. We look for the existence of equilibria of the aggregated model and perform local stability analysis. Two main cases can occur. The first one corresponds to over-exploitation leading to fish extinction. At extinction, the fishing effort tends to a positive value. The second case corresponds to a durable fishery equilibrium which is globally asymptotically stable. In the later case, we show that there exists a number of fishing sites that optimizes the total catch of the fishery.     

The atypical Rho GTPase,RhoU, regulates cell-adhesion molecules during cardiac morphogenesis

The vertebrate heart undergoes early complex morphologic events in order to develop key cardiac structures that regulate its overall function (Fahed et al., 2013). Although many genetic factors that participate in patterning the heart have been elucidated (Tu and Chi, 2012), the cellular events that drive cardiac morphogenesis have been less clear. From a chemical genetic screen to identify cellular pathways that control cardiac morphogenesis in zebrafish, we observed that inhibition of the Rho signaling pathways resulted in failure to form the atrioventricular canal and loop the linear heart tube. To identify specific Rho proteins that may regulate this process, we analyzed cardiac expression profiling data and discovered that RhoU was expressed at the atrioventricular canal during the time when it forms. Loss of RhoU function recapitulated the atrioventricular canal and cardiac looping defects observed in the ROCK inhibitor treated zebrafish. Similar to its family member RhoV/Chp (Tay et al., 2010), we discovered that RhoU regulates the cell junctions between cardiomyocytes through the Arhgef7b/Pak kinase pathway in order to guide atrioventricular canal development and cardiac looping. Inhibition of this pathway resulted in similar underlying cardiac defects and conversely, overexpression of a PAK kinase was able to rescue the loss of RhoU cardiac defect. Finally, we found that Wnt signaling, which has been implicated in atrioventricular canal development (Verhoeven et al., 2011), may regulate the expression of RhoU at the atrioventricular canal. Overall, these findings reveal a cardiac developmental pathway involving RhoU/Arhgef7b/Pak signaling, which helps coordinate cell junction formation between atrioventricular cardiomyocytes to promote cell adhesiveness and cell shapes during cardiac morphogenesis. Failure to properly form these cell adhesions during cardiac development may lead to structural heart defects and mechanistically account for the cellular events that occur in certain human congenital heart diseases.     

Novel substituted pyrrolidines are high affinity histamine H3 receptor antagonists

Pre-clinical characterization of novel substituted pyrrolidines that are high affinity histamine H₃ receptor antagonists is described. These compounds efficiently penetrate the CNS and occupy the histamine H₃ receptor in rat brain following oral administration. One compound, (2S,4R)-1-[2-(4-cyclobutyl-[1,4]diazepane-1-carbonyl)-4-(3-fluoro-phenoxy)-pyrrolidin-1-yl]-ethanone, was extensively profiled and shows promise as a potential clinical candidate.     

阴囊黄癣痂样石膏样小孢子菌感染1例

报道1例石膏样小孢子菌感染引起阴囊黄癣痂样皮损。患者,男,20岁,阴囊黄色痂皮3周。皮损取材真菌镜检可见分隔菌丝,培养为石膏样小孢子菌。口服伊曲康唑200mg/d,连续2周。停药时皮损消退,真菌学检查阴性。     

近平滑念珠菌的形态转换观察

目的观察近平滑念珠菌在不同培养基的形态转换现象,以及温度对其形态转换的影响。方法收集近平滑念珠菌正常人皮肤携带株及临床致病株和标准株,接种于改良Lee培养基和含桃红B的YPD培养基,观察其不同形态转换,以及温度变化对光滑(W)与皱褶(O)形态转换的影响。结果近平滑念珠菌在Lee培养基和含桃红B的YPD培养基上,均可以出现多种形态以及一定频率W-O转换现象。在观察W向O形态转换过程中发现,与25℃培养温度相比,37℃条件下光滑菌落形态占更多的比例。结论近平滑念珠菌体外培养时存在形态转换及W-O转换现象,且于37℃时更易保持光滑形态。含桃红B的YPD培养基也可以用于基本的W-O形态转换观察。     

ST段抬高型心肌梗死患者血钾水平与原发性恶性室性心律失常的相关研究

目的:探讨ST段抬高型心肌梗死(STEMI)患者与冠状动脉造影阴性的对照组血钾水平以及低血钾发病率的差异;探讨STEMI患者中原发性恶性室性心律失常组和非原发性恶性室性心律失常组血钾水平的差异.方法:选取2007年1月至2009年11月间STEMI并行直接经皮冠状动脉介入术(直接PCI)患者371例,其中男303例,女68例,平均年龄(56.1±11.7)岁.同时选取冠状动脉造影阴性患者(对照组)161例,其中男性131人,女性30人,平均年龄(56.8±10.3)岁.两组基线资料无显著性差异.将血钾含量＜3.5mmol/l定义为低血钾,比较2组间血钾含量及低血钾发病率.根据直接PCI之前是否发生原发性室颤和持续性室速,将STEMI患者分为原发性恶性室性心律失常组和非原发性恶性室性心律失常组,本组数据所指原发性恶性室性心律失常仅包括直接PCI之前发生的原发性室颤和持续性室速,其中原发性室颤24例,持续性室速11例.比较2组间血钾水平.结果:血钾含量STEMI患者(3.81±0.49)低于对照者(4.03+0.41)mmol/L,差异有统计学意义(t=5.08,P＜0.001).低血钾发病率STEMI(22.6%)高于对照者(6.83%),差异有统计学意义(X2=19.13,P＜0.001).STEMI患者中原发性恶性室性心律失常组和非原发性恶性室性心律失常组的血钾水平差异无统计学意义.结论:STEMI患者急性期存在血钾的下降,我们需要积极纠正低血钾,但低血钾与原发性恶性室性心律失常有无必然联系仍需更深入的研究.     

A new method to measure cortical growth in the developing brain

Folding of the cerebral cortex is a critical phase of brain development in higher mammals but the biomechanics of folding remain incompletely understood. During folding, the growth of the cortical surface is heterogeneous and anisotropic. We developed and applied a new technique to measure spatial and directional variations in surface growth from longitudinal magnetic resonance imaging (MRI) studies of a single animal or human subject. MRI provides high resolution 3D image volumes of the brain at different stages of development. Surface representations of the cerebral cortex are obtained by segmentation of these volumes. Estimation of local surface growth between two times requires establishment of a point-to-point correspondence ("registration") between surfaces measured at those times. Here we present a novel approach for the registration of two surfaces in which an energy function is minimized by solving a partial differential equation on a spherical surface. The energy function includes a strain-energy term due to distortion and an "error energy" term due to mismatch between surface features. This algorithm, implemented with the finite element method, brings surface features into approximate alignment while minimizing deformation in regions without explicit matching criteria. The method was validated by application to three simulated test cases and applied to characterize growth of the ferret cortex during folding. Cortical surfaces were created from MRI data acquired in vivo at 14 days, 21 days, and 28 days of life. Deformation gradient and Lagrangian strain tensors describe the kinematics of growth over this interval. These quantitative results illuminate the spatial, temporal, and directional patterns of growth during cortical folding.     

成人退行性腰椎侧弯合并滑脱的手术治疗

目的:探讨退行性腰椎侧弯合并滑脱的手术方法和临床疗效.方法:25例适应证患者行后路椎弓根螺钉内固定复位矫形后,采用椎管减压、神经根松解,行椎间植骨和后外侧植骨融合术,术后测量退变性脊柱侧弯的矫正效果,依照日本整形外科学会(JOA)下腰痛评分,观察腰腿疼痛改善情况.结果:全部病例获得随访,随访时间6月～3年,平均20个月,术后平均侧弯矫正率58.7%,疼痛改善优良率80%.结论:椎弓根固定系统结合椎间及后外侧植骨融合术是治疗退行性腰椎侧弯合并滑脱的有效方法.应重视术中神经根减压,矫正腰椎侧弯,恢复腰椎力学平衡,有助于提高远期疗效.     

90例原发性癫痫患者睡眠呼吸障碍及其相关事件分析

目的:探讨原发性癫痫患者夜间睡眠呼吸障碍及相关事件的特点.方法:对90例原发性癫痫患者进行夜间多导睡眠图(PSG)检查.分析夜间睡眠呼吸暂停低通气指数、睡眠各期SPO2值及相关腿动事件.结果:本组病人的PSG检测结果表现为SPO2监测显示有26.67%的患者合并有睡眠呼吸暂停低通气综合症(SAHS),合并SAHS组与不合并SAHS组在年龄、体重指数、是否合并高血压病方面进行比较P均<0.05,其差异有统计学意义.两组在病程、性别、发作形式、有无痫样放电、有无周期性腿动方面比较P值均>0.05,其差异无统计学意义.SPO2仪显示癫痫患者夜间存在不同程度低氧事件,其中SPO2最低值均发生在REM期.肌电显示孤立性腿动指数增加人数为27例(占30%),周期性腿动指数增加人数为15人(占16.67%),其中因激醒事件及呼吸事件因素而导致腿动指数增加分别占一定比例,且腿动事件主要集中在NREM期.结论:原发性癫痫患者常伴有睡眠呼吸障碍及夜间低氧事件.