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Application of CT 3D reconstruction in diagnosing atlantoaxial subluxation

Chinese Journal of Traumatology 2004年第2期7卷 118-121页

作者：段少银林清池庞瑞麟 First Clinical Academy of Medical College of Xiamen University Xiamen Zhongshan Hospital Medical Imaging Department First Affiliated HospitalKunming Medical College

Objective:To evaluate and compare the diagnosti c value in atlantoaxial subluxation by CT three-dimensional (3D) reconstruction . Methods:3D reconstruction findings of 41 patients with atlanto axial subluxation were retrospectively analyzed, and comparisons were made among images of transverse section, multiplanar reformorting (MPR), surface shade dis play (SSD), maximum intensity project (MIP), and volume rendering (VR). Results:Of 41 patients with atlantoaxial subluxation, 31 belon ged to rotary dislocation, 5 antedislocation, and 5 hind dislocation. All the ca ses showed the dislocated joint panel of atlantoaxial articulation. Fifteen case s showed deviation of the odontoid process and 8 cases widened distance between the dens and anterior arch of the atlas. The dislocated joint panel of atlantoax ial articulation was more clearly seen with SSD-3D imaging than any other metho ds. Conclusions:Atlantoaxial subluxation can well be diagnosed by CT 3D reconstruction, in which SSD-3D imaging is optimal.

关键词： Joints, atlantoaxial Tomography, X-ray computed image processing, computer-assisted

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Value of multidetector spiral CT in diagnosis of acute thoracolumbar spinal fracture and fracture-dislocation

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Chinese Journal of Traumatology 2004年第5期7卷 289-293页

作者：龚静山徐坚民 Department of Radiology Shenzhen People's Hospital (Second Affiliated Hospital School of Medicine Jinan University) Shenzhen 518020 Guangdong Province China

Objective: To investigate the diagnostic value of multidetector spiral CT (MSCT) in acute thoracolumbar spinal fracture and fracture-dislocation. Methods: CT imaging files of 152 consecutive traumatic patients with thoracolumbar fractures were retrospectively reviewed. MSCT scannings were performed with a collimation of 3-5 mm and a pitch of (5.5). The postprocessing included sagittal and coronal multiplannar reconstruction, and 3-D ***: There were 88 cases of compression fracture, 54 cases of burst fracture and 10 cases of fracture-dislocation. Transverse images of MSCT could visualize all fractures directly and determine whether spinal canal was intact. Postprocessing image was helpful in depicting the displacement of fragment and orientation of ***: MSCT plays an important role in diagnosis and management of acute thoracolumbar spinal fracture and fracture-dislocation.

关键词： image processing, computer-assisted Tomography, Spiral Computed Adult Aged Cohort Studies Comparative Study Female Follow-Up Studies Fracture Fixation Fracture Healing Humans Injury Severity Score Lumbar Vertebrae Male Middle Aged Retrospective Studies Risk Assessment Sensitivity and Specificity Spinal Fractures Thoracic Vertebrae Treatment Outcome

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Structural analysis of the photosystem I supercomplex of cyanobacteria induced by iron deficiency

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BIOCHEMISTRY 2003年第11期42卷 3180-3188页

作者： Nield, J Morris, EP Bibby, TS Barber, J Univ London Imperial Coll Sci Technol & Med Dept Biol Sci Wolfson Labs London SW7 2AZ England

Here we describe the three-dimensional structure of the newly discovered CP43'-photosystem I (PSI) supercomplex of cyanobacteria calculated by single-particle analysis of images obtained by electron cryomicroscopy (cryo-EM). This large membrane protein complex has a molecular mass of approximately 2 MDa and is found in cyanobacteria when grown in iron deficient media. It is composed of a reaction center trimer surrounded by 18 subunits of the chlorophyll a binding CP43'protein, encoded by the isiA gene, which increases the light harvesting capacity of PSI by similar to70%. By modeling higher-resolution structural data obtained from X-ray crystallography into the three-dimensional (3D) cryo-EM map, we have been able to gain a better understanding of the structure and functional properties of this supermolecular complex. We have identified three separate clusters of chlorophyll molecules at the periphery of the PSI core which may aid energy transfer from the CP43' antenna ring to the reaction center. Moreover, it is shown that despite the replacement of ferredoxin with flavodoxin as an electron acceptor under iron stress conditions, the 3D map has density to accommodate the extrinsic proteins, PsaC, PsaD, and PsaE. The presence of these three proteins was also confirmed by immunoblotting.

关键词： Cryoelectron Microscopy Crystallography, X-Ray Cyanobacteria/chemistry image processing, computer-assisted Iron/chemistry Models, Molecular Photosynthetic Reaction Center Complex Proteins/chemistry Photosynthetic Reaction Center Complex Proteins/chemistry Photosynthetic Reaction Center Complex Proteins/ultrastructure Photosynthetic Reaction Center Complex Proteins/ultrastructure Protein Conformation

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The structure of photosystem II in Arabidopsis:: Localization of the CP26 and CP29 antenna complexes

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BIOCHEMISTRY 2003年第3期42卷 608-613页

作者： Yakushevska, AE Keegstra, W Boekema, EJ Dekker, JP Andersson, J Jansson, S Ruban, AV Horton, P Univ Sheffield Dept Mol Biol & Biotechnol Robert Hill Inst Sheffield S10 2TN S Yorkshire England Univ Groningen Groningen Biomol Sci & Biotechnol Inst NL-9747 AG Groningen Netherlands Free Univ Amsterdam Div Phys & Astron Fac Sci NL-1081 HV Amsterdam Netherlands Umea Univ Dept Plant Physiol Umea Plant Sci Ctr S-90187 Umea Sweden

A genetic approach has been adopted to investigate the organization of the light-harvesting proteins in the photosystem II (PSII) complex in plants. PSII membrane fragments were prepared from wild-type Arabidopis thaliana and plants expressing antisense constructs to Lhcb4 and Lhcb5 genes, lacking CP29 and CP26, respectively (Andersson et al. (2001) Plant Cell 13, 1193-1204). Ordered PSII arrays and PSII supercomplexes were isolated from the membranes of plants lacking CP26 but could not be prepared from those lacking CP29. Membranes and supercomplexes lacking CP26 were less stable than those prepared from the wild type. Transmission electron microscopy aided by single-particle image analysis was applied to the ordered arrays and the isolated PSII complexes. The difference between the images obtained from wild type and antisense plants showed the location of CP26 to be near CP43 and one of the light-harvesting complex trimers. Therefore, the location of the CP26 within PSII was directly established for the first time, and the location of the CP29 complex was determined by elimination. Alterations in the packing of the PSII complexes in the thylakoid membrane also resulted from the absence of CP26. The minor light-harvesting complexes each have a unique location and important roles in the stabilization of the oligomeric PSII structure.

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Old botanical techniques for new microscopes

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BIOTECHNIQUES 2003年第6期34卷 1174-+页

作者： Haseloff, J Univ Cambridge Dept Plant Sci Cambridge CB2 3EA England

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The ATPase activity of the ChlI subunit of magnesium chelatase and formation of a heptameric AAA⁺ ring

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BIOCHEMISTRY 2003年第22期42卷 6912-6920页

作者： Reid, JD Siebert, CA Bullough, PA Hunter, CN Univ Sheffield Krebs Inst Biomolec Res Dept Mol Biol & Biotechnol Sheffield S10 2TN S Yorkshire England

The AAA(+) ATPase component of magnesium chelatase (ChlI) drives the insertion of Mg2+ into protoporphyrin IX;this is the first step in chlorophyll biosynthesis. We describe the ATPase activity, nucleotide binding kinetics, and structural organization of the ChII protein. A consistent reaction scheme arises from our detailed steady state description of the ATPase activity of the ChlI subunit and from transient kinetic analysis of nucleotide binding. We provide the first demonstration of metal ion binding to a specific subunit of any of the multimeric chelatases and characterize binding of Mg2+ to the free and MgATp(2-) bound forms of ChlI. Transient kinetic studies with the fluorescent substrate analogue TNP-ATP show that there are two forms of monomeric enzyme, which have distinct magnesium binding properties. Additionally, we describe the self-association properties of the subunit and provide a structural analysis of the multimeric ring formed by this enzyme in the presence of nucleotide. This single particle analysis demonstrates that this species has a 7-fold rotational symmetry, which is in marked contrast to most members of the AAA(+) family that tend to form hexamers.

关键词： Adenosine Triphosphatases/metabolism Adenosine Triphosphate/analogs & derivatives Adenosine Triphosphate/metabolism Chromatography, Gel Cryoelectron Microscopy/methods Hydrolysis image processing, computer-assisted Isomerism Kinetics Lyases/chemistry Lyases/metabolism Magnesium/chemistry Magnesium/metabolism Protein Structure, Tertiary Protein Subunits/metabolism Recombinant Proteins/chemistry Recombinant Proteins/metabolism

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Molecular architecture of the multiprotein splicing factor SF3b

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SCIENCE 2003年第5621期300卷 980-984页

作者： Golas, MM Sander, B Will, CL Lührmann, R Stark, H Max Planck Inst Biophys Chem D-37077 Gottingen Germany

The splicing factor SF3b is a multiprotein complex essential for the accurate excision of introns from pre-messenger RNA. As an integral component of the U2 small nuclear ribonucleoprotein (snRNP) and the U11/U12 di-snRNP, SF3b is involved in the recognition of the pre-messenger RNA's branch site within the major and minor spliceosomes. We have determined the three-dimensional structure of the human SF3b complex by single-particle electron cryomicroscopy at a resolution of less than 10 angstroms, allowing identification of protein domains with known structural folds. The best fit of a modeled RNA-recognition motif indicates that the protein p14 is located in the central cavity of the complex. The 22 tandem helical repeats of the protein SF3b155 are located in the outer shell of the complex enclosing p14.

关键词： Amino Acid Motifs Cryoelectron Microscopy Hela Cells Humans image processing, computer-assisted Macromolecular Substances Models, Molecular Multiprotein Complexes Phosphoproteins/chemistry Protein Conformation Protein Folding Protein Structure, Secondary Protein Structure, Tertiary Repetitive Sequences, Amino Acid Ribonucleoprotein, U2 Small Nuclear/chemistry RNA Precursors/chemistry RNA Precursors/metabolism RNA Splicing RNA-Binding Proteins Spliceosomes/chemistry Spliceosomes/metabolism

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High-probability uniquantal transmission at excitatory synapses in barrel cortex

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SCIENCE 2003年第5652期302卷 1981-1984页

作者： Silver, RA Lübke, J Sakmann, B Feldmeyer, D UCL Dept Physiol London WC1E 6BT England Forschungszentrum Julich Inst Med D-52425 Julich Germany Max Planck Inst Med Res Zellphysiol Abt D-69120 Heidelberg Germany

The number of vesicles released at excitatory synapses and the number of release sites per synaptic connection are key determinants of information processing in the cortex, yet they remain uncertain. Here we show that the number of functional release sites and the number of anatomically identified synaptic contacts are equal at connections between spiny stellate and pyramidal cells in rat barrel cortex. Moreover, our results indicate that the amount of transmitter released per synaptic contact is independent of release probability and the intrinsic release probability is high. These properties suggest that connections between layer 4 and layer 2/3 are tuned for reliable transmission of spatially distributed, timing-based signals.

关键词： Action Potentials Analysis of Variance Animals Axons/physiology Axons/ultrastructure Calcium/pharmacology Dendrites/physiology Dendrites/ultrastructure Dipeptides/pharmacology Excitatory Amino Acid Antagonists/pharmacology Excitatory Postsynaptic Potentials/drug effects Glutamic Acid/metabolism Glutamic Acid/metabolism image processing, computer-assisted Kynurenic Acid/pharmacology Lysine/analogs & derivatives Patch-Clamp Techniques Patch-Clamp Techniques Probability Pyramidal Cells/physiology Rats Rats, Wistar Receptors, Glutamate/metabolism Somatosensory Cortex/cytology Somatosensory Cortex/physiology Synapses/physiology Synaptic Transmission/physiology

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Imaging the distribution and secondary structure of immobilized enzymes using infrared microspectroscopy

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BIOMACROMOLECULES 2003年第1期4卷 70-74页

作者： Mei, Y Miller, L Gao, W Gross, RA Polytech Univ NSF I UCRC Biocatalysis & Bioproc Macromol MetroTech Ctr 6 Brooklyn NY 11201 USA Brookhaven Natl Lab Upton NY 11973 USA

Synchrotron infrared microspectroscopy (SIRMS) was used for the first time to image the distribution and secondary structure of an enzyme (lipase B from Candida antarctica, CALB) immobilized within a macroporous polymer matrix (poly(methyl methacrylate)) at 10 mum resolution. The beads of this catalyst (Novozyme435) were cut into thin sections (12 mum). SIRMS imaging of these thin sections revealed that the enzyme is localized in an external shell of the bead with a thickness of 80-100 mum. Also, the enzyme was unevenly distributed throughout this shell. Furthermore, by SIRMS-generated spectra, it was found that CALB secondary structure was not altered by immobilization. Unlike CALB, polystyrene molecules of similar molecular weight diffuse easily throughout Novozyme435 beads. Scanning electron micrograph (SEM) images of the Novozyme435 beads showed that the average pore size is 10 times larger than CALB or polystyrene molecules, implying that there is no physical barrier to enzyme or substrate diffusion throughout the bead. Thus, the difference between polystyrene and enzyme diffusivity suggests that protein-matrix and protein-protein interactions govern the distribution of the enzyme within the macroporous resin.

关键词： Candida/enzymology Enzymes, Immobilized/chemistry Enzymes, Immobilized/ultrastructure image processing, computer-assisted Lipase/chemistry Lipase/ultrastructure Microscopy, Electron, Scanning Polymethyl Methacrylate Protein Structure, Secondary Sensitivity and Specificity Spectrophotometry, Infrared

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Three-dimensional structure of herpes simplex virus from cryo-electron tomography

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SCIENCE 2003年第5649期302卷 1396-1398页

作者： Grünewald, K Desai, P Winkler, DC Heymann, JB Belnap, DM Baumeister, W Steven, AC NIAMSD Struct Biol Lab NIH Bethesda MD 20892 USA Johns Hopkins Univ Dept Pharmacol & Mol Sci Baltimore MD 21205 USA CALTECH Div Biol Pasadena CA 91125 USA Max Planck Inst Biochem Dept Mol Struct Biol D-82152 Martinsried Germany

Herpes simplex virus, a DNA virus of high complexity, consists of a nucleocapsid surrounded by the tegument-a protein compartment-and the envelope. The latter components, essential for infectivity, are pleiomorphic. Visualized in cryo-electron tomograms of isolated virions, the tegument was seen to form an asymmetric cap: On one side, the capsid closely approached the envelope;on the other side, they were separated by similar to35 nanometers of tegument. The tegument substructure was particulate, with some short actin-like. laments. The envelope contained 600 to 750 glycoprotein spikes that varied in length, spacing, and in the angles at which they emerge from the membrane. Their distribution was nonrandom, suggesting functional clustering.

关键词： Animals Capsid/chemistry Capsid/ultrastructure Cercopithecus aethiops Cryoelectron Microscopy Herpesvirus 1, Human/chemistry Herpesvirus 1, Human/physiology Herpesvirus 1, Human/ultrastructure Humans image processing, computer-assisted Lipid Bilayers Nucleocapsid/ultrastructure Tomography Vero Cells Viral Envelope Proteins/analysis Viral Envelope Proteins/ultrastructure Virion/ultrastructure

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