烟雾病5例临床分析

目的：研究烟雾病（moyamoya disease,MMD）的临床及影像学特征。方法：回顾性分析5例烟雾病患者,分析其临床及影像学特点。结果：本组病例既往均无阳性病史,中、青年起病,男性居多,均以缺血性脑血管病起病,肢体瘫痪不重,经颅多普勒（TCD）及头颅核磁改变明显,数字减影血管造影（DSA）检查均存在血管闭塞及侧支开放,烟雾血管网形成,1例MRA证实烟雾血管网形成。结论：对于无既往史的中、青年脑卒中患者,要考虑MMD的可能,需完善TCD、头核磁检寻找证据,最后完善数字减影血管造影确诊。     

颅内静脉系统血栓形成6例临床分析

目的：探讨颅内静脉系统血栓形成（CVT）的临床表现、影像学特征以及治疗方法对临床诊断的意义。方法：回顾性分析首都医科大学宣武医院收治的6例CVT患者的临床表现及影像学特征与治疗方法。结果：6例临床表现无特殊,4例经MRI＋MRV确诊,3例DSA检查确诊,1例介入治疗,4例抗凝治疗,2例保守,无死亡患者。结论：静脉系统血栓形成临床症状缺乏特异性,临床遇到急性起病的头痛、呕吐,伴或不伴有局灶性神经功能缺损或癫痫发作、意识障碍的青中年人,应高度怀疑CVT。早期应用抗凝、溶栓等治疗方法,对改善预后具有较高的临床应用价值。     

The use of ionisation constants of amino acids for protein signal analysis within the resonant recognition model--application to proteases

Biological functions of proteins and their active 3D structures are determined by the linear sequences of amino acids. The resonant recognition model (RRM) is a physico-mathematical model developed for structure/function analysis of protein and DNA sequences. Here, we are comparing results of the RRM analysis [1,2] of protease proteins using the electron-ion interaction potential (EIIP) and ionisation constant (IC) of amino acids. The results obtained reveal that the IC parameter can be successfully used to determine the characteristic patterns of different functional protease subgroups.     

Infrared study of trifluoroacetic acid unpurified synthetic peptides in aqueous solution: trifluoroacetic acid removal and band assignment

Synthetic peptide or protein samples are mostly unpurified with trifluoroacetic acid (TFA) used during the synthesis procedure, which strongly interferes with structure determination by infrared (IR) spectroscopy. The aim of this work was to propose a simple strategy to remove TFA contribution from attenuated total reflection (ATR)–IR spectra of the hexahistidine peptide (His6) in aqueous solution to study the conformation of this synthetic peptide without previous purification. Such a strategy is based on the subtraction mode widely employed to remove water contribution, and it is tested with TFA unpurified histidine as a model system. The subtraction is based on eliminating the strong TFA bands at 1147 and 1200 cm⁻¹ by applying a scaling factor (as in buffer correction). The proposed modes represent excellent strategies that do not modify spectral features, and they provide reliable routines to obtain the synthetic peptide spectrum without TFA contribution. The conformational information from the corrected spectra at different pH values is deduced from semiempirical calculated IR spectra of different His6 conformers. The spectral features and the band positions of the corrected spectrum suggest that the peptide molecules mainly adopt an intermolecular β-sheet structure.     

Visualizing the internal structure of polyethylene glycol-impregnated wood by digital breast tomosynthesis

This study proposes digital breast tomosynthesis (DBT) as a low-tube-voltage method for imaging wood artifacts treated with polyethylene glycol (PEG). In case of general clinical X-ray Computed Tomography (X-CT), PEG-impregnated wood images typically suffer from low contrast between the PEG and the tree-ring. Because X-CT uses high-tube-voltage X-rays that have high energy, they are transmitted regardless of the X-ray absorption difference of the substance, and therefore, it is not suitable for imaging PEG-impregnated wood. Mammography uses low-tube-voltage X-rays, and therefore, it is suitable for delineating substances with small X-ray absorption differences. However, although mammography can produce high-contrast images of wood, it cannot distinguish three-dimensional (3D) structures such as tree rings, because those are projection images. DBT is a type of mammography used to enhance contrast using low-tube voltage, and it enables imaging 3D structures by exposure X-rays to objects several times changing the exposure angle, and it can obtain quasi-computed tomography. Therefore, we believe that by applying DBT to dendroarchaeology, it would be possible to obtain high-contrast, high-resolution images in the visualization of the internal structure of wood.In this study, we used clinical X-CT, mammography, and DBT to obtain images of wood after PEG impregnation, and we evaluated the internal structure of the wood and the visibility of annual rings. We obtained DBT images as a tomogram with a thickness of 1 mm, which eliminated the distortion of tree rings in the sagittal direction and duplication of the PEG and the tree-ring. Further, tree-rings were easily visualized without a noticeable blur, and the DBT contrast was improved compared to clinical X-CT contrast because DBT was performed at low voltage. Important wooden artifacts excavated from ruins were preserved by PEG. Therefore, this method can be expected to become a very useful tool for dendroarchaeology when used as a complementary tool for microfocus X-CT.     

数字化骨科理念辅助椎弓根置钉在寰枢椎不稳中的临床应用

目的:探讨3D打印辅助置钉技术用于寰枢椎不稳椎弓根置钉的安全性及准确性。方法:收集2013年1月到2015年1月西安交通大学第一附属医院收治的寰枢椎不稳病例,术前采用3D打印技术构建个体化3D打印模型,在模型上模拟置钉,获取最佳置钉点、置钉角度等个体化置钉数据,并于术中辅助椎弓根螺钉置入。通过CT扫描评价置钉准确性,测量术前、术后患者寰齿间隙判断寰枢椎复位情况,测量颈延角评价脊髓压迫改善情况,并采用日本骨科学会(JOA)评分判断患者脊髓功能改善情况。术后定期随访观察固定效果、稳定性、神经损伤等手术并发症的发生情况。结果:13例患者均采用3D打印辅助置钉技术进行内固定治疗,手术顺利,术中及术后无血管、神经损伤等并发症,复位及内固定效果满意。共置入椎弓根螺钉31枚,其中29枚完全在椎弓根内,置钉准确率为93.5%。寰枢椎较术前明显复位,术后寰齿间隙、颈延角和JOA评分较术前明显改善,差异具有统计学意义(P0.05)。结论:3D打印技术辅助上颈椎椎弓根置钉的准确性及安全性均较高。     

Changes in sexual signals are greater than changes in ecological traits in a dichromatic group of fishes

Understanding the mechanisms by which phenotypic divergence occurs is central to speciation research. These mechanisms can be revealed by measuring differences in traits that are subject to different selection pressures; greater influence of different types of selection can be inferred from greater divergence in associated traits. Here, we address the potential roles of natural and sexual selection in promoting phenotypic divergence between species of snubnose darters by comparing differences in body shape, an ecologically relevant trait, and male color, a sexual signal. Body shape was measured using geometric morphometrics, and male color was measured using digital photography and visual system‐dependent color values. Differences in male color are larger than differences in body shape across eight allopatric, phylogenetically independent species pairs. While this does not exclude the action of divergent natural selection, our results suggest a relatively more important role for sexual selection in promoting recent divergence in darters. Variation in the relative differences between male color and body shape across species pairs reflects the continuous nature of speciation mechanisms, ranging from ecological speciation to speciation by sexual selection alone.