Coordinated regulation of the dorsal‐ventral and anterior‐posterior patterning of Xenopus embryos by the BTB/POZ zinc finger protein Zbtb14

During early vertebrate embryogenesis, bone morphogenetic proteins (BMPs) belonging to the transforming growth factor‐β (TGF‐β) family of growth factors play a central role in dorsal–ventral (DV) patterning of embryos, while other growth factors such as Wnt and fibroblast growth factor (FGF) family members regulate formation of the anterior–posterior (AP) axis. Although the establishment of body plan is thought to require coordinated formation of the DV and AP axes, the mechanistic details underlying this coordination are not well understood. Here, we show that a Xenopus homologue of zbtb14 plays an essential role in the regulation of both DV and AP patterning during early Xenopus development. We show that overexpression of Zbtb14 promotes neural induction and inhibits epidermal differentiation, thereby regulating DV patterning. In addition, Zbtb14 promotes the formation of posterior neural tissue and suppresses anterior neural development. Consistent with this, knock‐down experiments show that Zbtb14 is required for neural development, especially for the formation of posterior neural tissues. Mechanistically, Zbtb14 reduces the levels of phosphorylated Smad1/5/8 to suppress BMP signaling and induces an accumulation of β‐Catenin to promote Wnt signaling. Collectively, these results suggest that Zbtb14 plays a crucial role in the formation of DV and AP axes by regulating both the BMP and Wnt signaling pathways during early Xenopus embryogenesis.     

Left posterior fascicular block,state-of-the-art review: A 2018 update

We conducted a review of the literature regarding epidemiology, clinical, electrocardiographic and vectorcardiographic aspects, classification, and differential diagnosis of left posterior fascicular block.Isolated left posterior fascicular block (LPFB) is an extremely rare finding both in the general population and in specific patient groups. In isolated LPFB 20% of the vectorcardiographic (VCG) QRS loop is located in the right inferior quadrant and when associated with right bundle branch block (RBBB) ≥40%.The diagnosis of LPFB should always consider the clinical aspects, because a definite diagnosis cannot be made in the presence of right ventricular hypertrophy (RVH) (chronic obstructive pulmonary disease (COPD)/emphysema), extensive lateral myocardial infarction (MI) or extremely vertical heart.Intermittent LPFBs are never complete blocks (transient or second degree LPFB) and even in the permanent ones, one cannot be sure that they are complete. When LPFB is associated with RBBB and acute inferior MI, PR interval prolongation is very frequent.     

绿盲蝽中枢神经系统的解剖结构

【目的】阐述绿盲蝽Apolygus lucorum中枢神经系统的组成,辨识各组成部分的神经节解剖结构及其形态,计算中枢神经系统各神经节结构体积大小、解析其空间分布关系以及连接模式。【方法】采用免疫组织化学方法,使用突触蛋白抗体对绿盲蝽中枢神经系统神经髓进行染色标记,利用共聚焦激光扫描显微镜获取中枢神经系统各结构数码图像,使用三维图像分析软件对绿盲蝽中枢神经系统进行分析,并构建三维模型。【结果】绿盲蝽中枢神经系统从前往后分别由脑神经节、咽下神经节、前胸神经节和后部神经节组成。脑、咽下神经节和前胸神经节3个神经节融合在一块,形成脑-咽下神经节-前胸神经节复合体,并通过长的神经连索与后部神经节相连,从外观上看似由2个大的神经节构成,这种神经节愈合形式尚未在昆虫中发现过。前胸神经节与后部神经节分离,二者由长的神经连索连接起来。除前胸神经节由单独的神经原节构成外,其他3个神经节又由多个神经原节融合而成。脑包括前脑、中脑和后脑3部分。咽下神经节包括上颚神经节、下颚神经节和下唇神经节。后部神经节包括中胸、后胸和腹部神经节3部分。【结论】明确了绿盲蝽中枢神经系统的神经节构成,发现了绿盲蝽中枢神经系统各神经节的高度融合特性。该项研究结果为研究绿盲蝽中枢神经系统的发育、重塑和系统演化奠定了形态学基础,为研究中枢神经元形态、分布以及其对昆虫生理和行为的功能调控机制提供了结构框架。     

Posterior predictive checks of coalescent models: P2C2M,an R package

Bayesian inference operates under the assumption that the empirical data are a good statistical fit to the analytical model, but this assumption can be challenging to evaluate. Here, we introduce a novel r package that utilizes posterior predictive simulation to evaluate the fit of the multispecies coalescent model used to estimate species trees. We conduct a simulation study to evaluate the consistency of different summary statistics in comparing posterior and posterior predictive distributions, the use of simulation replication in reducing error rates and the utility of parallel process invocation towards improving computation times. We also test P2C2M on two empirical data sets in which hybridization and gene flow are suspected of contributing to shared polymorphism, which is in violation with the coalescent model: Tamias chipmunks and Myotis bats. Our results indicate that (i) probability‐based summary statistics display the lowest error rates, (ii) the implementation of simulation replication decreases the rate of type II errors, and (iii) our r package displays improved statistical power compared to previous implementations of this approach. When probabilistic summary statistics are used, P2C2M corroborates the assumption that genealogies collected from Tamias and Myotis are not a good fit to the multispecies coalescent model. Taken as a whole, our findings argue that an assessment of the fit of the multispecies coalescent model should accompany any phylogenetic analysis that estimates a species tree.     

经骨折椎体椎弓根螺钉短节段固定治疗胸腰段骨折疗效

目的:评估和分析经骨折椎体椎弓根螺钉短节段固定治疗胸腰段单椎体粉碎性骨折的临床疗效。方法:选取胸腰段单椎体粉碎性骨折30例患者,分为两组,甲组20例,采用经骨折椎体椎弓根螺钉短节段固定治疗,均行骨折椎体及骨折椎体上下相邻椎体的椎弓根螺钉+双侧连接杆固定;乙组10例,只行骨折椎体的上下相邻椎体的椎弓根螺钉+连接杆固定术。术后随访。测定两组患者手术前后的椎体后凸畸形角和骨折椎体前方高度,评估其临床疗效。结果:术前平均后凸畸形角纠正:甲组15°,乙组11°,P0.05。术后骨折椎体前方的平均高度(和正常椎体前方高度比):甲组89%,乙组81%,P0.05;术后3个月随访:平均后凸畸形角纠正丢失,甲组2°,乙组6°,P0.05;骨折椎体前方的平均高度(和正常椎体前方高度比):甲组87%,乙组73%,P0.05。结论:经骨折椎体椎弓根螺钉短节段固定治疗胸腰段单椎体粉碎性骨折能提供更好的生物力学稳定性,更有利于骨折的复位和后凸畸形的纠正。     

一种游仆虫棘毛基部纤维的形态及其在形态发生过程中的演化

游仆虫皮层棘毛基部纤维包括纵纤维、前纵纤维和放射纤维:额腹棘毛基部后纵纤维一般长而粗大,前纵纤维次之,放射纤维较细小;横棘毛基部前纵纤维几乎纵贯额腹横棘毛区皮层,而放射纤维较为细小;尾棘毛基部仅与一类更为细小的放射纤维相联系。不同额腹棘毛基部的同种纤维大小、形态不尽一致,各种纤维由棘毛基部区向皮层细胞质多个方向伸展,表现出极性和不对称性。并且额腹横棘毛基部纤维相互交联在一起,导致这一皮层区域形成强大的棘毛基部纤维网络。 游仆虫形态发生中,横棘毛原基向皮层裂口上方伸出一束粗大的纤毛芽时,先后发生模棘毛原基前纵纤维芽、额腹棘毛原基后纵纤维芽,以及这些棘毛原基放射纤维芽。纤维芽的发育顺序是从左列棘毛原基开始,到右侧的棘毛原基。这种纤维物质生长的顺序性,与新棘毛原基的发生和分化是相一致的。并且额腹棘毛基部后纵纤维和横棘毛基部前纵纤维形成中显示出极性和方向性,纤维物质生长伸长的方向与相应的新棘毛迁移方向相反。 老棘毛基部纤维在游仆虫形态发生过程中必然要退化。我们推测,其瓦解过程与细胞分化中老棘毛逐渐失去功能是有联系的。     

胚胎型大脑后动脉与脑白质病之间的关系

目的:探讨胚胎型大脑后动脉(Fetal origin of the posterior cerebral artery,FTP)与脑白质病之间的关系。方法:收集2013年1月~2014年6月在我院住院患者共485例,所有患者均行头颅磁共振平扫及血管成像,观察脑白质病变、急性脑梗死及FTP存在与否,并分为观察组(脑白质病组)和对照组(无脑白质病组),比较FTP的发生率。结果:观察组和对照组分别为232例和253例,观察组共发现53例FTP患者(左侧、右侧、双侧FTP分别为15例、19例、19例),FTP总发生率为22.8%,左侧、右侧、双侧FTP发生率分别为6.5%、8.2%、8.2%;对照组98例FTP患者(左侧、右侧、双侧FTP分别为26例、44例、28例),FTP总发生率为38.7%,左侧、右侧、双侧FTP发生率分别为10.3%、17.4%、11.1%,观察组FTP总发生率及右侧FTP发生率明显低于对照组(P0.001和P0.01)。232例观察组中急性脑梗死患者共156例,无急性脑梗死患者76例,其中急性脑梗死组有28例FTP患者(左侧、右侧、双侧FTP分别为7例、15例、6例),FTP总发生率及左侧、右侧、双侧FTP发生率分别为17.9%、4.5%、9.6%、3.8%;而无急性脑梗死的患者中,有24例FTP患者(左侧、右侧、双侧FTP分别为8例、4例、12例),FTP总发生率及左侧、右侧、双侧FTP发生率分别为31.6%、10.5%、5.3%、15.8%,观察组FTP总发生率及双侧FTP发生率明显低于对照组(P0.05和P0.01)。结论:FTP的存在可能一定程度上降低脑白质病甚至脑梗死的发生。     

Assessing site-interdependent phylogenetic models of sequence evolution

In recent works, methods have been proposed for applying phylogenetic models that allow for a general interdependence between the amino acid positions of a protein. As of yet, such models have focused on site interdependencies resulting from sequence-structure compatibility constraints, using simplified structural representations in combination with a set of statistical potentials. This structural compatibility criterion is meant as a proxy for sequence fitness, and the methods developed thus far can incorporate different site-interdependent fitness proxies based on other measurements. However, no methods have been proposed for comparing and evaluating the adequacy of alternative fitness proxies in this context, or for more general comparisons with canonical models of protein evolution. In the present work, we apply Bayesian methods of model selection-based on numerical calculations of marginal likelihoods and posterior predictive checks-to evaluate models encompassing the site-interdependent framework. Our application of these methods indicates that considering site-interdependencies, as done here, leads to an improved model fit for all data sets studied. Yet, we find that the use of pairwise contact potentials alone does not suitably account for across-site rate heterogeneity or amino acid exchange propensities; for such complexities, site-independent treatments are still called for. The most favored models combine the use of statistical potentials with a suitably rich site-independent model. Altogether, the methodology employed here should allow for a more rigorous and systematic exploration of different ways of modeling explicit structural constraints, or any other site-interdependent criterion, while best exploiting the richness of previously proposed models.