Towards correlative super‐resolution fluorescence and electron cryo‐microscopy

Correlative light and electron microscopy (CLEM) has become a powerful tool in life sciences. Particularly cryo‐CLEM, the combination of fluorescence cryo‐microscopy (cryo‐FM) permitting for non‐invasive specific multi‐colour labelling, with electron cryo‐microscopy (cryo‐EM) providing the undisturbed structural context at a resolution down to the Ångstrom range, has enabled a broad range of new biological applications. Imaging rare structures or events in crowded environments, such as inside a cell, requires specific fluorescence‐based information for guiding cryo‐EM data acquisition and/or to verify the identity of the structure of interest. Furthermore, cryo‐CLEM can provide information about the arrangement of specific proteins in the wider structural context of their native nano‐environment. However, a major obstacle of cryo‐CLEM currently hindering many biological applications is the large resolution gap between cryo‐FM (typically in the range of ～400 nm) and cryo‐EM (single nanometre to the Ångstrom range). Very recently, first proof of concept experiments demonstrated the feasibility of super‐resolution cryo‐FM imaging and the correlation with cryo‐EM. This opened the door towards super‐resolution cryo‐CLEM, and thus towards direct correlation of structural details from both imaging modalities.     

Machine learning approaches in MALDI-MSI: clinical applications

Introduction: Despite the unquestionable advantages of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging in visualizing the spatial distribution and the relative abundance of biomolecules directly on-tissue, the yielded data is complex and high dimensional. Therefore, analysis and interpretation of this huge amount of information is mathematically, statistically and computationally challenging.

Areas covered: This article reviews some of the challenges in data elaboration with particular emphasis on machine learning techniques employed in clinical applications, and can be useful in general as an entry point for those who want to study the computational aspects. Several characteristics of data processing are described, enlightening advantages and disadvantages. Different approaches for data elaboration focused on clinical applications are also provided. Practical tutorial based upon Orange Canvas and Weka software is included, helping familiarization with the data processing.

Expert commentary: Recently, MALDI-MSI has gained considerable attention and has been employed for research and diagnostic purposes, with successful results. Data dimensionality constitutes an important issue and statistical methods for information-preserving data reduction represent one of the most challenging aspects. The most common data reduction methods are characterized by collecting independent observations into a single table. However, the incorporation of relational information can improve the discriminatory capability of the data.     

Dual‐function fluorescent probe for cancer imaging and therapy

To date, several fluorescent probes modified by a single targeting agent have been explored. However, studies on the preparation of dual‐function quantum dot (QD) fluorescent probes with dual‐targeting action and a therapeutic effect are rare. Here, a dual‐targeting CdTe/CdS QD fluorescent probe with a bovine serum albumin–glycyrrhetinic acid conjugate and arginine‐glycine‐aspartic acid was successfully prepared that could induce the apoptosis of liver cancer cells and showed enhanced targeting in in vitro cell imaging. Therefore, the as‐prepared fluorescent probe in this work is an efficient diagnostic tool for the simultaneous detection of liver cancer and breast cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.     

弥散张量成像对脑室周围白质软化患儿术后脑白质恢复的评估作用

目的:研究弥散张量成像(DTI)对脑室周围白质软化(PVL)患儿选择性脊神经后根切除术(SPR)后脑白质恢复的评估价值。方法:选取从2014年1月至2015年8月在新疆医科大学二附院脑瘫中心择期行SPR手术治疗的PVL患儿40例作为观察组,另选同期磁共振成像(MRI)检查正常儿童40例作为对照组,两组分别在手术前后进行DTI检查,比较两组不同部位的部分各向异性值(FA)及表观弥散系数(ADC)。结果:术前观察组不同部位的FA值均显著低于对照组,胼胝体压部的ADC值显著高于对照组,差异均有统计学意义(P0.05)。与术前比较,术后观察组不同部位的FA值均上升,胼胝体压部的ADC值下降,差异均有统计学意义(P0.05),且与对照组之间的差异无统计学意义(P0.05)。结论:SPR术能够明显控制PVL患儿的病情,且采用DTI成像技术能够客观地反应PVL患儿SPR术后脑白质恢复情况,对辅助临床治疗和预后评估具有重要作用。     

Three dimensional patient-specific collagen architecture modulates cartilage responses in the knee joint during gait

Site-specific variation of collagen fibril orientations can affect cartilage stresses in knee joints. However, this has not been confirmed by 3-D analyses. Therefore, we present a novel method for evaluation of the effect of patient-specific collagen architecture on time-dependent mechanical responses of knee joint cartilage during gait. 3-D finite element (FE) models of a human knee joint were created with the collagen architectures obtained from T₂ mapped MRI (patient-specific model) and from literature (literature model). The effect of accuracy of the implementation of collagen fibril architecture into the model was examined by using a submodel with denser FE mesh. Compared to the literature model, fibril strains and maximum principal stresses were reduced especially in the superficial/middle regions of medial tibial cartilage in the patient-specific model after the loading response of gait (up to ?413 and ?26%, respectively). Compared to the more coarsely meshed joint model, the patient-specific submodel demonstrated similar strain and stress distributions but increased values particularly in the superficial cartilage regions (especially stresses increased >60%). The results demonstrate that implementation of subject-specific collagen architecture of cartilage in 3-D modulates location- and time-dependent mechanical responses of human knee joint cartilage. Submodeling with more accurate implementation of collagen fibril architecture alters cartilage stresses particularly in the superficial/middle tissue.     

Heterogeneous MR arthrography findings in patients with subacromial impingement syndrome – Diagnostic subgroups?

BackgroundSubacromial Impingement Syndrome (SIS) is frequently diagnosed, but treatment results vary greatly. It is increasingly reported that SIS symptoms are caused by various underlying mechanisms that need distinctive treatment strategies. We evaluated a set of specific MRI Arthrography (MRA) characteristics that have been related with underlying mechanisms for SIS in the literature, in patients with SIS.MethodsIn 47 patients diagnosed with SIS, MRA characteristics were evaluated and categorized into categories of potential underlying mechanisms: (1) extrinsic: e.g. acromion shape; (2) intrinsic: e.g. tendinosis; (3) dynamic: e.g. signs of glenohumeral (micro-)instability. Control values were obtained from the literature. With cluster analysis, potential patient subgroups were assessed.ResultsIn 17 (36.2%) patients originally diagnosed with SIS, specific other conditions were found, including rotator cuff tears and labrum lesions. In the remaining 30, all had positive signs of at least one of the predefined underlying mechanisms. Patients could be categorized into 2 groups: predominantly findings corresponding with extrinsic/structural causes, or with dynamic/(micro)instability.ConclusionsMRA characteristics in patients with SIS symptoms are heterogeneous and many patients have specific other shoulder conditions causing symptoms. Patients without specific other conditions have MRA characteristics associated with either extrinsic (structural), or dynamic (e.g. micro-instability) underlying mechanisms.     

Progress and Challenges for Live-cell Imaging of Genomic Loci Using CRISPR-based Platforms

Chromatin conformation,localization,and dynamics are crucial regulators of cellular behaviors. Although fluorescence in situ hybridization-based techniques have been widely utilized for investigating chromatin architectures in healthy and diseased states,the requirement for cell fix-ation precludes the comprehensive dynamic analysis necessary to fully understand chromatin activ-ities. This has spurred the development and application of a variety of imaging methodologies for visualizing single chromosomal loci in the native cellular context. In this review,we describe currently-available approaches for imaging single genomic loci in cells,with special focus on clus-tered regularly interspaced short palindromic repeats (CRISPR)-based imaging approaches. In addition,we discuss some of the challenges that limit the application of CRISPR-based genomic imaging approaches,and potential solutions to address these challenges. We anticipate that,with continued refinement of CRISPR-based imaging techniques,significant understanding can be gained to help decipher chromatin activities and their relevance to cellular physiology and pathogenesis.     

Design and synthesis of a new fluorescent probe for cascade detection of Zn2+ and H2PO4− in water and targeted imaging of living cells

Design and synthesis of new fluorescence probes with good water‐solubility is of great importance to better understanding the significant role of ions which are related to biology and the environment. As important ions, zinc ion (Zn²⁺) and dihydrogen phosphate ion (H₂PO₄^?) display essential roles in living systems, and quantitative detection of these ions in water is still a challenge. In order to consider the significant role of the galactose moiety in the design of a water‐soluble fluorescence sensor, herein, we have developed a novel probe, Gal‐AQTF, for the cascade detection of Zn²⁺ and H₂PO₄^? with excellent selectivity in water. Through the introduction of the galactose moiety onto the sensor AQTF, which has been reported earlier by us, the water‐solubility, cell compatibility and targeting ability were enhanced. Gal‐AQTF has been successfully applied in the imaging of the living cells of HepG2 and A549, and illustrated good selectivity for the HepG2 cells which overly express the asialoglycoprotein (ASGP) receptor.     

Driving Precision Medicine through Proteomics and Metabolomics - 12th Central and Eastern European Proteomic Conference (CEEPC), Bucharest,Romania

As Romanians prepared to celebrate 100 years of the '‘Great Unification of 1918?' which united all provinces into one Romania, the 12^th Central and Eastern European Proteomic Conference (CEEPC) jointly with the 39^th Anniversary of the Institute of Cellular Biology and Pathology '‘N. Simionescu’' (ICBP-NS), held their inaugural meeting at the Romanian Academy in Bucharest – a national forum of highest scientific recognition. With an exciting theme entitled, ‘Advances in Proteomics and Progress in Precision Medicine’, delegates gathered to debate Precision medicine’s revolution in diagnosis and treatment, which now accounts for predictive, preventative, and targeted treatment strategies with informed decisions according to individual’s unique clinical, molecular and genetic profile. Proteomics has a pivotal role to play in furthering precision health and medicine for the benefit of mankind. To this end, CEEPC continues to drive advances in proteomics, metabolomics, and diseases as well as raising awareness of pressing global humanitarian and health-care issues including mental health diseases, aging, chronic diseases, global epidemics and environmental issues. Today, CEEPC is a well-recognized major annual conference with a focused vision and a highly valued ideology as it continues to propagate scientific, medical and proteomic collaborations whilst expanding as more Eastern European countries prepare to join.