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Electron tomography

Malika Ouldali, Virginie Maury, Gisèle Nicolas, Jean Lepault
Polynoid worm elytra emit light when mechanically or electrically stimulated. Specialized cells, the photocytes, contain light emitting machineries, the photosomes. Successive stimulations induce light intensity variations and show a coupling within and between photosomes. Here, we describe, using electron tomography of cryo-substituted elytra and freeze-fracturing, the structural transition associated to light emission: undulating tubules come closer, organize and their number forming photosomes increases...
December 4, 2017: Journal of Structural Biology
Johanna M Meulepas, Michael Hauptmann, Jay H Lubin, Igor Shuryak, David J Brenner
Recently reported studies have associated radiation exposure from computed tomography (CT) scanning with small excess cancer risks. However, since existing medical records were used in these studies, they could not control for reasons for the CT scans and therefore, the results may have been confounded by indication. Here we conducted a study to estimate potential indication bias that could affect hazard ratios for colorectal, lung and female breast cancers by reasons for a CT scan. This involved a retrospective cohort study of electronic records from all patients aged 18-89 years without previous cancer diagnoses, who received at least one CT scan at Columbia University Medical Center in the period of 1994-2014...
December 5, 2017: Radiation Research
Tessa E F Quax, Bertram Daum
Viruses have developed intricate molecular machines to infect, replicate within and escape from their host cells. Perhaps one of the most intriguing of these mechanisms is the pyramidal egress structure that has evolved in archaeal viruses, such as SIRV2 or STIV1. The structure and mechanism of these virus-associated pyramids (VAPs) has been studied by cryo-electron tomography and complementary biochemical techniques, revealing that VAPs are formed by multiple copies of a virus-encoded 10-kDa protein (PVAP) that integrate into the cell membrane and assemble into hollow, sevenfold symmetric pyramids...
December 4, 2017: Biophysical Reviews
Abhishek Jha, Alexander Ling, Corina Millo, Garima Gupta, Bruna Viana, Frank I Lin, Peter Herscovitch, Karen T Adams, David Taïeb, Adam R Metwalli, W Marston Linehan, Alessandra Brofferio, Constantine A Stratakis, Electron Kebebew, Maya Lodish, Ali Cahid Civelek, Karel Pacak
PURPOSE: To evaluate and compare diagnostic performance of 68Ga-DOTA(0)-Tyr(3)-octreotate (68Ga-DOTATATE) with 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) and anatomic imaging using computed tomography and/or magnetic resonance (CT/MR) imaging in detection of SDHx-related pheochromocytomas and paragangliomas (PPGLs) in pediatric patients. METHODS: Nine pediatric patients (5:4, girls:boys; 14.6 ± 2.0 years) with an SDHx-related mutation (SDHB:SDHA:SDHD, n = 7:1:1) were included in this retrospective study...
December 4, 2017: European Journal of Nuclear Medicine and Molecular Imaging
Andrea S Weisberg, Liliana Maruri-Avidal, Himani Bisht, Bryan T Hansen, Cindi L Schwartz, Elizabeth R Fischer, Xiangzhi Meng, Yan Xiang, Bernard Moss
The long-standing inability to visualize connections between poxvirus membranes and cellular organelles has led to uncertainty regarding the origin of the viral membrane. Indeed, there has been speculation that viral membranes form de novo in cytoplasmic factories. Another possibility, that the connections are too short-lived to be captured by microscopy during a normal infection, motivated us to identify and characterize virus mutants that are arrested in assembly. Five conserved vaccinia virus proteins, referred to as Viral Membrane Assembly Proteins (VMAPs), that are necessary for formation of immature virions were found...
December 4, 2017: Proceedings of the National Academy of Sciences of the United States of America
Xiang Zhang, Yun-Fei Ma, Lei Wang, Nan Jiang, Cheng-He Qin, Yan-Jun Hu, Bin Yu
Currently, animal models used in research on implant-associated osteomyelitis primarily use intramedullary fixation and initial inoculum of planktonic bacterial cells. However, these techniques have certain limitations, including lack of rotational stability and instable inoculation. To improve these models, the present study aimed to establish a novel rabbit model of implant-associated osteomyelitis using biofilm as the initial inoculum following plate fixation of the femoral fracture. A total of 24 New Zealand White rabbits were randomly divided into two equal groups...
November 2017: Experimental and Therapeutic Medicine
Nathaniel P Chongsiriwatana, Jennifer S Lin, Rinki Kapoor, Modi Wetzler, Jennifer A C Rea, Maruti K Didwania, Christopher H Contag, Annelise E Barron
Many organisms rely on antimicrobial peptides (AMPs) as a first line of defense against pathogens. In general, most AMPs are thought to kill bacteria by binding to and disrupting cell membranes. However, certain AMPs instead appear to inhibit biomacromolecule synthesis, while causing less membrane damage. Despite an unclear understanding of mechanism(s), there is considerable interest in mimicking AMPs with stable, synthetic molecules. Antimicrobial N-substituted glycine (peptoid) oligomers ("ampetoids") are structural, functional and mechanistic analogs of helical, cationic AMPs, which offer broad-spectrum antibacterial activity and better therapeutic potential than peptides...
December 1, 2017: Scientific Reports
Hemant Mahajan, Jina Choo, Kamal Masaki, Akira Fujiyoshi, Jingchuan Guo, Takashi Hisamatsu, Rhobert Evans, Siyi Shangguan, Bradley Willcox, Tomonori Okamura, Abhishek Vishnu, Emma Barinas-Mitchell, Vasudha Ahuja, Katsuyuki Miura, Lewis Kuller, Chol Shin, Hirotsugu Ueshima, Akira Sekikawa
BACKGROUND AND AIMS: Several studies have reported a significant inverse association of light to moderate alcohol consumption with coronary heart disease (CHD). However, studies assessing the relationship between alcohol consumption and atherosclerosis have reported inconsistent results. The current study was conducted to determine the relationship between alcohol consumption and aortic calcification. METHODS: We addressed the research question using data from the population-based ERA-JUMP Study, comprising of 1006 healthy men aged 40-49 years, without clinical cardiovascular diseases, from four race/ethnicities: 301 Whites, 103 African American, 292 Japanese American, and 310 Japanese in Japan...
November 21, 2017: Atherosclerosis
Qi Xie, Dong Zeng, Qian Zhao, Deyu Meng, Zongben Xu, Zhengrong Liang, Jianhua Ma
Computed tomography (CT) image recovery from low-mAs acquisitions without adequate treatment is always severely degraded due to a number of physical factors. In this paper, we formulate the low-dose CT sinogram preprocessing as a standard maximum a posteriori (MAP) estimation, which takes full consideration of the statistical properties of the two intrinsic noise sources in low-dose CT, i.e., the X-ray photon statistics and the electronic noise background. In addition, instead of using a general image prior as found in the traditional sinogram recovery models, we design a new prior formulation to more rationally encode the piecewise-linear configurations underlying a sinogram than previously used ones, like the TV prior term...
December 2017: IEEE Transactions on Medical Imaging
Song Yang, Jing Wu, Si Lei
RATIONALE AND OBJECTIVE: The computed tomography (CT) features of hepatic veno-occlusive disease (HVOD) could play a role in its diagnosis. We aimed to perform a meta-analysis of studies examining the CT features of HVOD. METHODS: Relevant studies published up to May 3, 2017 were searched in major electronic databases. The extracted data included the proportion of various CT features in patients with HVOD. The meta-analysis was conducted using R 3.3.3 with the "meta" package...
November 27, 2017: Academic Radiology
Emilie Billaud, Sarah Belderbos, Frederik Cleeren, Wim Maes, Marlies Van de Wouwer, Michel Koole, Alfons Verbruggen, Uwe Himmelreich, Nick Geukens, Guy Bormans
In cancer research, pretargeted positron emission tomography (PET) imaging has emerged as an effective two-step approach that combines the excellent target affinity and selectivity of antibodies with the advantages of using short-lived radionuclides such as fluorine-18. One possible approach is based on the bioorthogonal inverse-electron-demand Diels-Alder (IEDDA) reaction between tetrazines and trans-cyclooctene (TCO) derivatives. Here, we report the first successful use of an 18F-labeled small TCO compound, [18F]1 recently developed in our laboratory, to perform pretargeted immuno-PET imaging...
November 30, 2017: Bioconjugate Chemistry
Yuki M Shirai, Taka A Tsunoyama, Nao Hiramoto-Yamaki, Koichiro M Hirosawa, Akihiro C E Shibata, Kenichi Kondo, Atsushi Tsurumune, Fumiyoshi Ishidate, Akihiro Kusumi, Takahiro K Fujiwara
Electron tomography of the plasma membrane (PM) identified several layers of cortical actin meshwork running parallel to the PM cytoplasmic surface throughout the PM. Here, cortical actin structures and dynamics were examined in living cells, using super-resolution microscopy, with (x,y)- and z-resolutions of ~140 and ~400 nm, respectively, and single-molecule imaging. The super-resolution microscopy identified sub-micron-sized actin clusters that appeared identical by both phalloidin post-fixation staining and Lifeact-mGFP expression followed by fixation, and therefore, these actin clusters were named "actin-pl-clusters"...
2017: PloS One
Igor Orlov, Robert Drillien, Danièle Spehner, Max Bergoin, Adly M M Abd-Alla, Bruno P Klaholz
Glossina palipides salivary gland hypertrophy virus (GpSGHV) infects tsetse flies, which are vectors for African trypanosomosis. This virus represents a major challenge in insect mass rearing and has hampered the implementation of the sterile insect technique programs in the Member States of the International Atomic Energy Agency. GpSGHV virions consist of long rod-shaped particles over 9000Å in length, but little is known about their detailed structural organization. We show by cryo electron microscopy and cryo electron tomography that the GpSGHV virion has a unique, non-icosahedral helical structure...
November 27, 2017: Virology
Kirsten R Carlaw, Henry H Woo
Background: Approaches to prostate cancer (PCa) diagnosis and treatment have evolved significantly over past decades. There has been an increasing focus on minimizing overdiagnosis and overtreatment of clinically insignificant PCa. The objective of this study was to evaluate the changes in the diagnostic approach and initial treatment strategy that has evolved over time in an Australian urological private practice. Materials and methods: Men with newly diagnosed PCa were identified from the private practice electronic and paper medical records from 2005 to 2016 and data was consolidated into six groups of 2-year intervals...
December 2017: Prostate International
Sang-Yeop Chung, Mohamed Abd Elrahman, Pawel Sikora, Teresa Rucinska, Elzbieta Horszczaruk, Dietmar Stephan
Recently, the recycling of waste glass has become a worldwide issue in the reduction of waste and energy consumption. Waste glass can be utilized in construction materials, and understanding its effects on material properties is crucial in developing advanced materials. In this study, recycled crushed and expanded glasses are used as lightweight aggregates for concrete, and their relation to the material characteristics and properties is investigated using several approaches. Lightweight concrete specimens containing only crushed and expanded waste glass as fine aggregates are produced, and their pore and structural characteristics are examined using image-based methods, such as scanning electron microscopy (SEM), X-ray computed tomography (CT), and automated image analysis (RapidAir)...
November 25, 2017: Materials
Anish N Sen, Jared Fridley, Sherly Sebastian, Edward A M Duckworth
BACKGROUND: Intraoperative computed tomography angiography (ICTA) is a novel completion imaging modality for carotid endarterectomy (CEA). No studies exist in the literature describing ICTA use in CEA. OBJECTIVE: To evaluate the feasibility and efficacy of ICTA as a method of immediately evaluating the technical results of CEA. METHODS: Twenty-three consecutive CEAs were performed by a single neurosurgeon over an 8-month period. Of this series, 12 utilized ICTA for completion imaging, 10 utilized duplex ultrasonography (US), and 1 utilized no intraoperative completion imaging...
December 1, 2017: Operative Neurosurgery (Hagerstown, Md.)
Zihao Wang, Yu Chen, Jingrong Zhang, Lun Li, Xiaohua Wan, Zhiyong Liu, Fei Sun, Fa Zhang
Electron tomography (ET) is an important technique for studying the three-dimensional structures of the biological ultrastructure. Recently, ET has reached sub-nanometer resolution for investigating the native and conformational dynamics of macromolecular complexes by combining with the sub-tomogram averaging approach. Due to the limited sampling angles, ET reconstruction typically suffers from the "missing wedge" problem. Using a validation procedure, iterative compressed-sensing optimized nonuniform fast Fourier transform (NUFFT) reconstruction (ICON) demonstrates its power in restoring validated missing information for a low-signal-to-noise ratio biological ET dataset...
November 29, 2017: Journal of Computational Biology: a Journal of Computational Molecular Cell Biology
Dario Ferreira Sanchez, Alexandre S Simionovici, Laurence Lemelle, Vera Cuartero, Olivier Mathon, Sakura Pascarelli, Anne Bonnin, Russell Shapiro, Kurt Konhauser, Daniel Grolimund, Pierre Bleuet
X-ray spectroscopic techniques have proven to be particularly useful in elucidating the molecular and electronic structural information of chemically heterogeneous and complex micro- and nano-structured materials. However, spatially resolved chemical characterization at the micrometre scale remains a challenge. Here, we report the novel hyperspectral technique of micro Energy Dispersive X-ray Absorption Spectroscopy (μED-XAS) tomography which can resolve in both 2D and 3D the spatial distribution of chemical species through the reconstruction of XANES spectra...
November 28, 2017: Scientific Reports
R S Louro, J A Calasans-Maia, C T Mattos, D Masterson, M D Calasans-Maia, L C Maia
The aim of this study was to evaluate the effect of counterclockwise (CCW) rotation and maxillomandibular advancement (MMA) on the upper airway space using three-dimensional images. An electronic search was performed in the PubMed, Cochrane Library, Scopus, Virtual Health Library, Web of Science, and OpenGrey databases (end date July 2016); a hand-search of primary study reference lists was also conducted. The inclusion criteria encompassed computed tomography evaluations of the upper airway spaces of adult patients undergoing orthognathic surgery with CCW rotation and MMA...
November 25, 2017: International Journal of Oral and Maxillofacial Surgery
Eric Berg, Simon R Cherry
Although there have been impressive strides in detector development for time-of-flight positron emission tomography (PET), most detectors still make use of simple signal processing methods to extract the time-of-flight information from the detector signals. In most cases, the timing pick-off for each waveform is computed using leading edge discrimination or constant fraction discrimination, as these were historically easily implemented with analog pulse processing electronics. However, now with the availability of fast waveform digitizers, there is opportunity to make use of more of the timing information contained in the coincident detector waveforms with advanced signal processing techniques...
November 28, 2017: Physics in Medicine and Biology
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