1
|
El Omari K, Forsyth I, Duman R, Orr CM, Mykhaylyk V, Mancini EJ, Wagner A. Utilizing anomalous signals for element identification in macromolecular crystallography. Acta Crystallogr D Struct Biol 2024; 80:713-721. [PMID: 39291627 PMCID: PMC11448921 DOI: 10.1107/s2059798324008659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 09/03/2024] [Indexed: 09/19/2024] Open
Abstract
AlphaFold2 has revolutionized structural biology by offering unparalleled accuracy in predicting protein structures. Traditional methods for determining protein structures, such as X-ray crystallography and cryo-electron microscopy, are often time-consuming and resource-intensive. AlphaFold2 provides models that are valuable for molecular replacement, aiding in model building and docking into electron density or potential maps. However, despite its capabilities, models from AlphaFold2 do not consistently match the accuracy of experimentally determined structures, need to be validated experimentally and currently miss some crucial information, such as post-translational modifications, ligands and bound ions. In this paper, the advantages are explored of collecting X-ray anomalous data to identify chemical elements, such as metal ions, which are key to understanding certain structures and functions of proteins. This is achieved through methods such as calculating anomalous difference Fourier maps or refining the imaginary component of the anomalous scattering factor f''. Anomalous data can serve as a valuable complement to the information provided by AlphaFold2 models and this is particularly significant in elucidating the roles of metal ions.
Collapse
|
2
|
El Omari K, Duman R, Mykhaylyk V, Orr CM, Latimer-Smith M, Winter G, Grama V, Qu F, Bountra K, Kwong HS, Romano M, Reis RI, Vogeley L, Vecchia L, Owen CD, Wittmann S, Renner M, Senda M, Matsugaki N, Kawano Y, Bowden TA, Moraes I, Grimes JM, Mancini EJ, Walsh MA, Guzzo CR, Owens RJ, Jones EY, Brown DG, Stuart DI, Beis K, Wagner A. Experimental phasing opportunities for macromolecular crystallography at very long wavelengths. Commun Chem 2023; 6:219. [PMID: 37828292 PMCID: PMC10570326 DOI: 10.1038/s42004-023-01014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/26/2023] [Indexed: 10/14/2023] Open
Abstract
Despite recent advances in cryo-electron microscopy and artificial intelligence-based model predictions, a significant fraction of structure determinations by macromolecular crystallography still requires experimental phasing, usually by means of single-wavelength anomalous diffraction (SAD) techniques. Most synchrotron beamlines provide highly brilliant beams of X-rays of between 0.7 and 2 Å wavelength. Use of longer wavelengths to access the absorption edges of biologically important lighter atoms such as calcium, potassium, chlorine, sulfur and phosphorus for native-SAD phasing is attractive but technically highly challenging. The long-wavelength beamline I23 at Diamond Light Source overcomes these limitations and extends the accessible wavelength range to λ = 5.9 Å. Here we report 22 macromolecular structures solved in this extended wavelength range, using anomalous scattering from a range of elements which demonstrate the routine feasibility of lighter atom phasing. We suggest that, in light of its advantages, long-wavelength crystallography is a compelling option for experimental phasing.
Collapse
|
3
|
Fadini A, Hutchison CDM, Morozov D, Chang J, Maghlaoui K, Perrett S, Luo F, Kho JCX, Romei MG, Morgan RML, Orr CM, Cordon-Preciado V, Fujiwara T, Nuemket N, Tosha T, Tanaka R, Owada S, Tono K, Iwata S, Boxer SG, Groenhof G, Nango E, van Thor JJ. Serial Femtosecond Crystallography Reveals that Photoactivation in a Fluorescent Protein Proceeds via the Hula Twist Mechanism. J Am Chem Soc 2023. [PMID: 37418747 PMCID: PMC10375524 DOI: 10.1021/jacs.3c02313] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Chromophore cis/trans photoisomerization is a fundamental process in chemistry and in the activation of many photosensitive proteins. A major task is understanding the effect of the protein environment on the efficiency and direction of this reaction compared to what is observed in the gas and solution phases. In this study, we set out to visualize the hula twist (HT) mechanism in a fluorescent protein, which is hypothesized to be the preferred mechanism in a spatially constrained binding pocket. We use a chlorine substituent to break the twofold symmetry of the embedded phenolic group of the chromophore and unambiguously identify the HT primary photoproduct. Through serial femtosecond crystallography, we then track the photoreaction from femtoseconds to the microsecond regime. We observe signals for the photoisomerization of the chromophore as early as 300 fs, obtaining the first experimental structural evidence of the HT mechanism in a protein on its femtosecond-to-picosecond timescale. We are then able to follow how chromophore isomerization and twisting lead to secondary structure rearrangements of the protein β-barrel across the time window of our measurements.
Collapse
|
4
|
Yu X, Orr CM, Chan HTC, James S, Penfold CA, Kim J, Inzhelevskaya T, Mockridge CI, Cox KL, Essex JW, Tews I, Glennie MJ, Cragg MS. Reducing affinity as a strategy to boost immunomodulatory antibody agonism. Nature 2023; 614:539-547. [PMID: 36725933 DOI: 10.1038/s41586-022-05673-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 12/20/2022] [Indexed: 02/03/2023]
Abstract
Antibody responses during infection and vaccination typically undergo affinity maturation to achieve high-affinity binding for efficient neutralization of pathogens1,2. Similarly, high affinity is routinely the goal for therapeutic antibody generation. However, in contrast to naturally occurring or direct-targeting therapeutic antibodies, immunomodulatory antibodies, which are designed to modulate receptor signalling, have not been widely examined for their affinity-function relationship. Here we examine three separate immunologically important receptors spanning two receptor superfamilies: CD40, 4-1BB and PD-1. We show that low rather than high affinity delivers greater activity through increased clustering. This approach delivered higher immune cell activation, in vivo T cell expansion and antitumour activity in the case of CD40. Moreover, an inert anti-4-1BB monoclonal antibody was transformed into an agonist. Low-affinity variants of the clinically important antagonistic anti-PD-1 monoclonal antibody nivolumab also mediated more potent signalling and affected T cell activation. These findings reveal a new paradigm for augmenting agonism across diverse receptor families and shed light on the mechanism of antibody-mediated receptor signalling. Such affinity engineering offers a rational, efficient and highly tuneable solution to deliver antibody-mediated receptor activity across a range of potencies suitable for translation to the treatment of human disease.
Collapse
|
5
|
Chukhutsina VU, Baxter JM, Fadini A, Morgan RM, Pope MA, Maghlaoui K, Orr CM, Wagner A, van Thor JJ. Light activation of Orange Carotenoid Protein reveals bicycle-pedal single-bond isomerization. Nat Commun 2022; 13:6420. [PMID: 36307413 PMCID: PMC9616832 DOI: 10.1038/s41467-022-34137-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 10/14/2022] [Indexed: 12/25/2022] Open
Abstract
Orange Carotenoid protein (OCP) is the only known photoreceptor which uses carotenoid for its activation. It is found exclusively in cyanobacteria, where it functions to control light-harvesting of the photosynthetic machinery. However, the photochemical reactions and structural dynamics of this unique photosensing process are not yet resolved. We present time-resolved crystal structures at second-to-minute delays under bright illumination, capturing the early photoproduct and structures of the subsequent reaction intermediates. The first stable photoproduct shows concerted isomerization of C9'-C8' and C7'-C6' single bonds in the bicycle-pedal (s-BP) manner and structural changes in the N-terminal domain with minute timescale kinetics. These are followed by a thermally-driven recovery of the s-BP isomer to the dark state carotenoid configuration. Structural changes propagate to the C-terminal domain, resulting, at later time, in the H-bond rupture of the carotenoid keto group with protein residues. Solution FTIR and UV/Vis spectroscopy support the single bond isomerization of the carotenoid in the s-BP manner and subsequent thermal structural reactions as the basis of OCP photoreception.
Collapse
|
6
|
Orr CM, Fisher H, Yu X, Chan CHT, Gao Y, Duriez PJ, Booth SG, Elliott I, Inzhelevskaya T, Mockridge I, Penfold CA, Wagner A, Glennie MJ, White AL, Essex JW, Pearson AR, Cragg MS, Tews I. Hinge disulfides in human IgG2 CD40 antibodies modulate receptor signaling by regulation of conformation and flexibility. Sci Immunol 2022; 7:eabm3723. [PMID: 35857577 DOI: 10.1126/sciimmunol.abm3723] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2024]
Abstract
Antibodies protect from infection, underpin successful vaccines and elicit therapeutic responses in otherwise untreatable cancers and autoimmune conditions. The human IgG2 isotype displays a unique capacity to undergo disulfide shuffling in the hinge region, leading to modulation of its ability to drive target receptor signaling (agonism) in a variety of important immune receptors, through hitherto unexplained molecular mechanisms. To address the underlying process and reveal how hinge disulfide orientation affects agonistic activity, we generated a series of cysteine to serine exchange variants in the hinge region of the clinically relevant monoclonal antibody ChiLob7/4, directed against the key immune receptor CD40. We report how agonistic activity varies with disulfide pattern and is afforded by the presence of a disulfide crossover between F(ab) arms in the agonistic forms, independently of epitope, as observed in the determined crystallographic structures. This structural "switch" affects directly on antibody conformation and flexibility. Small-angle x-ray scattering and ensemble modeling demonstrated that the least flexible variants adopt the fewest conformations and evoke the highest levels of receptor agonism. This covalent change may be amenable for broad implementation to modulate receptor signaling in an epitope-independent manner in future therapeutics.
Collapse
|
7
|
Fischer ES, Yu CWH, Bellini D, McLaughlin SH, Orr CM, Wagner A, Freund SMV, Barford D. Molecular mechanism of Mad1 kinetochore targeting by phosphorylated Bub1. EMBO Rep 2021; 22:e52242. [PMID: 34013668 PMCID: PMC8391104 DOI: 10.15252/embr.202052242] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/02/2021] [Accepted: 04/13/2021] [Indexed: 01/10/2023] Open
Abstract
During metaphase, in response to improper kinetochore-microtubule attachments, the spindle assembly checkpoint (SAC) activates the mitotic checkpoint complex (MCC), an inhibitor of the anaphase-promoting complex/cyclosome (APC/C). This process is orchestrated by the kinase Mps1, which initiates the assembly of the MCC onto kinetochores through a sequential phosphorylation-dependent signalling cascade. The Mad1-Mad2 complex, which is required to catalyse MCC formation, is targeted to kinetochores through a direct interaction with the phosphorylated conserved domain 1 (CD1) of Bub1. Here, we present the crystal structure of the C-terminal domain of Mad1 (Mad1CTD ) bound to two phosphorylated Bub1CD1 peptides at 1.75 Å resolution. This interaction is mediated by phosphorylated Bub1 Thr461, which not only directly interacts with Arg617 of the Mad1 RLK (Arg-Leu-Lys) motif, but also directly acts as an N-terminal cap to the CD1 α-helix dipole. Surprisingly, only one Bub1CD1 peptide binds to the Mad1 homodimer in solution. We suggest that this stoichiometry is due to inherent asymmetry in the coiled-coil of Mad1CTD and has implications for how the Mad1-Bub1 complex at kinetochores promotes efficient MCC assembly.
Collapse
|
8
|
Duman R, Orr CM, Mykhaylyk V, El Omari K, Pocock R, Grama V, Wagner A. Sample Preparation and Transfer Protocol for In-Vacuum Long-Wavelength Crystallography on Beamline I23 at Diamond Light Source. J Vis Exp 2021. [PMID: 33970149 DOI: 10.3791/62364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Long-wavelength macromolecular crystallography (MX) exploits the anomalous scattering properties of elements, such as sulfur, phosphorus, potassium, chlorine, or calcium, that are often natively present in macromolecules. This enables the direct structure solution of proteins and nucleic acids via experimental phasing without the need of additional labelling. To eliminate the significant air absorption of X-rays in this wavelength regime, these experiments are performed in a vacuum environment. Beamline I23 at Diamond Light Source, UK, is the first synchrotron instrument of its kind, designed and optimized for MX experiments in the long wavelength range towards 5 Å. To make this possible, a large vacuum vessel encloses all endstation components of the sample environment. The necessity to maintain samples at cryogenic temperatures during storage and data collection in vacuum requires the use of thermally conductive sample holders. This facilitates efficient heat removal to ensure sample cooling to approximately 50 K. The current protocol describes the procedures used for sample preparation and transfer of samples into vacuum on beamline I23. Ensuring uniformity in practices and methods already established within the macromolecular crystallography community, sample cooling to liquid nitrogen temperature can be performed in any laboratory setting equipped with standard MX tools. Cryogenic storage and transport of samples only require standard commercially available equipment. Specialized equipment is required for the transfer of cryogenically cooled crystals from liquid nitrogen into the vacuum endstation. Bespoke sample handling tools and a dedicated Cryogenic Transfer System (CTS) have been developed in house. Diffraction data collected on samples prepared using this protocol show excellent merging statistics, indicating that the quality of samples is unaltered during the procedure. This opens unique opportunities for in-vacuum MX in a wavelength range beyond standard synchrotron beamlines.
Collapse
|
9
|
Humbert MV, Jackson A, Orr CM, Tews I, Christodoulides M. Characterization of two putative Dichelobacter nodosus footrot vaccine antigens identifies the first lysozyme inhibitor in the genus. Sci Rep 2019; 9:10055. [PMID: 31296905 PMCID: PMC6624275 DOI: 10.1038/s41598-019-46506-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/24/2019] [Indexed: 12/17/2022] Open
Abstract
The Gram-negative anaerobic bacterium Dichelobacter nodosus (Dn) causes footrot in ruminants, a debilitating and highly contagious disease that results in necrotic hooves and significant economic losses in agriculture. Vaccination with crude whole-cell vaccine mixed with multiple recombinant fimbrial proteins can provide protection during species-specific outbreaks, but subunit vaccines containing broadly cross-protective antigens are desirable. We have investigated two D. nodosus candidate vaccine antigens. Macrophage Infectivity Potentiator Dn-MIP (DNO_0012, DNO_RS00050) and Adhesin Complex Protein Dn-ACP (DNO_0725, DNO_RS06795) are highly conserved amongst ~170 D. nodosus isolates in the https://pubmlst.org/dnodosus/ database. We describe the presence of two homologous ACP domains in Dn-ACP with potent C-type lysozyme inhibitor function, and homology of Dn-MIP to other putative cell-surface and membrane-anchored MIP virulence factors. Immunization of mice with recombinant proteins with a variety of adjuvants induced antibodies that recognised both proteins in D. nodosus. Notably, immunization with fimbrial-whole-cell Footvax vaccine induced anti-Dn-ACP and anti-Dn-MIP antibodies. Although all adjuvants induced high titre antibody responses, only antisera to rDn-ACP-QuilA and rDn-ACP-Al(OH)3 significantly prevented rDn-ACP protein from inhibiting lysozyme activity in vitro. Therefore, a vaccine incorporating rDn-ACP in particular could contribute to protection by enabling normal innate immune lysozyme function to aid bacterial clearance.
Collapse
|
10
|
Sutton EJ, Bradshaw RT, Orr CM, Frendéus B, Larsson G, Teige I, Cragg MS, Tews I, Essex JW. Evaluating Anti-CD32b F(ab) Conformation Using Molecular Dynamics and Small-Angle X-Ray Scattering. Biophys J 2018; 115:289-299. [PMID: 30021105 PMCID: PMC6050753 DOI: 10.1016/j.bpj.2018.03.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 02/16/2018] [Accepted: 03/27/2018] [Indexed: 11/04/2022] Open
Abstract
Complementary strategies of small-angle x-ray scattering (SAXS) and crystallographic analysis are often used to determine atomistic three-dimensional models of macromolecules and their variability in solution. This combination of techniques is particularly valuable when applied to macromolecular complexes to detect changes within the individual binding partners. Here, we determine the x-ray crystallographic structure of a F(ab) fragment in complex with CD32b, the only inhibitory Fc-γ receptor in humans, and compare the structure of the F(ab) from the crystal complex to SAXS data for the F(ab) alone in solution. We investigate changes in F(ab) structure by predicting theoretical scattering profiles for atomistic structures extracted from molecular dynamics (MD) simulations of the F(ab) and assessing the agreement of these structures to our experimental SAXS data. Through principal component analysis, we are able to extract principal motions observed during the MD trajectory and evaluate the influence of these motions on the agreement of structures to the F(ab) SAXS data. Changes in the F(ab) elbow angle were found to be important to reach agreement with the experimental data; however, further discrepancies were apparent between our F(ab) structure from the crystal complex and SAXS data. By analyzing multiple MD structures observed in similar regions of the principal component analysis, we were able to pinpoint these discrepancies to a specific loop region in the F(ab) heavy chain. This method, therefore, not only allows determination of global changes but also allows identification of localized motions important for determining the agreement between atomistic structures and SAXS data. In this particular case, the findings allowed us to discount the hypothesis that structural changes were induced upon complex formation, a significant find informing the drug development process. The methodology described here is generally applicable to deconvolute global and local changes of macromolecular structures and is well suited to other systems.
Collapse
|
11
|
Yu X, Chan HTC, Orr CM, Dadas O, Booth SG, Dahal LN, Penfold CA, O'Brien L, Mockridge CI, French RR, Duriez P, Douglas LR, Pearson AR, Cragg MS, Tews I, Glennie MJ, White AL. Complex Interplay between Epitope Specificity and Isotype Dictates the Biological Activity of Anti-human CD40 Antibodies. Cancer Cell 2018; 33:664-675.e4. [PMID: 29576376 PMCID: PMC5896247 DOI: 10.1016/j.ccell.2018.02.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/20/2017] [Accepted: 02/15/2018] [Indexed: 12/22/2022]
Abstract
Anti-CD40 monoclonal antibodies (mAbs) that promote or inhibit receptor function hold promise as therapeutics for cancer and autoimmunity. Rules governing their diverse range of functions, however, are lacking. Here we determined characteristics of nine hCD40 mAbs engaging epitopes throughout the CD40 extracellular region expressed as varying isotypes. All mAb formats were strong agonists when hyper-crosslinked; however, only those binding the membrane-distal cysteine-rich domain 1 (CRD1) retained agonistic activity with physiological Fc gamma receptor crosslinking or as human immunoglobulin G2 isotype; agonistic activity decreased as epitopes drew closer to the membrane. In addition, all CRD2-4 binding mAbs blocked CD40 ligand interaction and were potent antagonists. Thus, the membrane distal CRD1 provides a region of choice for selecting CD40 agonists while CRD2-4 provides antagonistic epitopes.
Collapse
|
12
|
Marzke MW, Tocheri MW, Steinberg B, Femiani JD, Reece SP, Linscheid RL, Orr CM, Marzke RF. Comparative 3D quantitative analyses of trapeziometacarpal joint surface curvatures among living catarrhines and fossil hominins. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2010; 141:38-51. [PMID: 19544574 DOI: 10.1002/ajpa.21112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Comparisons of joint surface curvature at the base of the thumb have long been made to discern differences among living and fossil primates in functional capabilities of the hand. However, the complex shape of this joint makes it difficult to quantify differences among taxa. The purpose of this study is to determine whether significant differences in curvature exist among selected catarrhine genera and to compare these genera with hominin fossils in trapeziometacarpal curvature. Two 3D approaches are used to quantify curvatures of the trapezial and metacarpal joint surfaces: (1) stereophotogrammetry with nonuniform rational B-spline (NURBS) calculation of joint curvature to compare modern humans with captive chimpanzees and (2) laser scanning with a quadric-based calculation of curvature to compare modern humans and wild-caught Pan, Gorilla, Pongo, and Papio. Both approaches show that Homo has significantly lower curvature of the joint surfaces than does Pan. The second approach shows that Gorilla has significantly more curvature than modern humans, while Pongo overlaps with humans and African apes. The surfaces in Papio are more cylindrical and flatter than in Homo. Australopithecus afarensis resembles African apes more than modern humans in curvatures, whereas the Homo habilis trapezial metacarpal surface is flatter than in all genera except Papio. Neandertals fall at one end of the modern human range of variation, with smaller dorsovolar curvature. Modern human topography appears to be derived relative to great apes and Australopithecus and contributes to the distinctive human morphology that facilitates forceful precision and power gripping, fundamental to human manipulative activities.
Collapse
|
13
|
Orr CM, Dufour DL, Patton JQ. A comparison of anthropometric indices of nutritional status in Tukanoan and Achuar Amerindians. Am J Hum Biol 2001; 13:301-9. [PMID: 11460895 DOI: 10.1002/ajhb.1053] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Anthropometric data from a Tukanoan population in the Vaupes region of Colombia and an Achuar population in the Ecuadorian Amazon were compared relative to international references. The Tukanoans exploit an oligotrophic blackwater ecosystem, whereas the Achuar inhabit a resource rich montane ecosystem. Given this ecological distinction, three hypotheses regarding nutritional statuses were proposed: (1) Tukanoans are significantly shorter than the Achuar, indicating a greater degree of stunting; (2) Tukanoans are significantly leaner, indicating a greater degree of wasting; and (3) Tukanaons have significantly lower upper arm muscle area, indicating lower lean body mass. Z-scores for height, weight-for-height, and estimated upper arm muscle area were determined and significant nutritional stress was assumed at z < or = -2.0. Between population differences in z-scores for height-for-age (ZHT), weight-for-height (ZWH), and upper arm muscle area (ZUMA) were examined using analysis of variance with a subsequent Scheffe's test. Between-group differences in the frequencies of individuals with low z-scores (z < or = -2.0) were assessed via chi-squared analysis. Both populations showed stunting in most age groups, but neither showed low ZWH or ZUMA. Significant differences between populations were found only for ZHT in children (females 1.0-4.9 and 5.0-9.9 years, and males 5.0-9.9 years). Tukanoans have significantly higher frequencies of stunting in all age-sex groups except females and males age 30-49.9 years. There were no significant between-population differences in the frequencies of individuals with low ZWH or ZUMA. These differences in nutritional status may reflect differences in resource availability.
Collapse
|
14
|
Nasser TK, Fry ET, Annan K, Khatib Y, Peters TF, VanTassel J, Orr CM, Waller BF, Pinto R, Pinkerton CA, Hermiller JB. Comparison of six-month outcome of coronary artery stenting in patients <65, 65-75, and >75 years of age. Am J Cardiol 1997; 80:998-1001. [PMID: 9352967 DOI: 10.1016/s0002-9149(97)00592-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We studied 1,238 patients receiving 1,880 coronary stents. In-hospital outcomes were divided by age into <65 years (n = 747, group 1), 65 to 75 years (n = 326, group 2), and >75 years (n = 165, group 3). Procedural success was 97.2%, 95.1%, and 98.8% in groups 1, 2, and 3, respectively (p = NS). There was 1 death (group 1). Myocardial infarction occurred in 1.2%, 2.8%, and 1.8%, bypass surgery occurred in 0.9%, 1.8%, and 1.2%, and repeat balloon angioplasty in 0.3%, 0.6%, and 0% of patients in groups 1, 2, and 3, respectively (p = NS for all comparisons). Vascular complications occurred in 2.8%, 4.9%, and 6.1% in groups 1, 2, and 3, respectively (p <0.05). Six-month follow-up of patients was divided by age: <65 years (n = 564, group 1); 65 to 75 years (n = 221, group 2); and >75 years (n = 122, group 3). Event-free survival was 94.5%, 90.5%, and 89.3% for groups 1, 2, and 3, respectively (p = NS). Death occurred in 0.4%, 0.5%, and 1.6%; myocardial infarction occurred in 1.2%, 2.3%, and 1.6%, and target vessel revascularization in 4.3%, 8.6%, and 7.4% for groups 1, 2, and 3, respectively (p = NS for all comparisons). Thus, coronary stenting produced favorable in-hospital and 6-month outcomes in all 3 age groups. Age itself should not preclude patients from undergoing coronary stenting.
Collapse
|
15
|
Surawicz B, Orr CM, Hermiller JB, Bell KD, Pinto RP. QRS changes during percutaneous transluminal coronary angioplasty and their possible mechanisms. J Am Coll Cardiol 1997; 30:452-8. [PMID: 9247518 DOI: 10.1016/s0735-1097(97)00165-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The purpose of the study was to describe the configuration, and investigate the mechanisms, of QRS changes occurring during percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND QRS changes during PTCA have been attributed to both a passive ST segment shift and conduction disturbances (peri-ischemic block). The direct relation between ST segment shift and QRS changes, however, has not been established, and the definition of conduction disturbances remains to be clarified. METHODS Twelve-lead electrocardiograms (ECGs) were recorded before PTCA, at the end of 2 min of PTCA and after return to baseline values in 29 patients (left anterior descending coronary artery [LAD] in 13 patients, right coronary artery [RCA] in 14 and left circumflex coronary artery in 2). Electrocardiographic complexes before and during PTCA were superimposed to determine the amplitudes of initial, terminal and total QRS deflection; the relations of QRS changes to baseline (TP segment) and ST segment shift; and the duration of QRS and corrected QT intervals. RESULTS. 1) The direction of the initial QRS deflection was unchanged, but changes of its amplitude occurred. 2) Terminal QRS deflection changed in all patients with a ST segment shift > 17% of the R amplitude, and the correlation between the decrease in the S amplitude and ST segment shift was significant (r = 0.9, p < 0.01) in patients with LAD PTCA. Correlation between changes in total QRS amplitude and ST segment shift in patients with RCA PTCA was weaker (r = 0.54, p = 0.056). 3) Transient conduction disturbance manifested by QRS widening in selected leads occurred in 2 of 29 patients. CONCLUSIONS. 1) Changes in terminal QRS deflection during PTCA are proportional to the magnitude of the ST segment shift. 2) Conduction disturbances manifested by increased QRS duration occurred infrequently. We suggest that the term peri-ischemic block be applied only to changes in QRS configuration associated with QRS widening.
Collapse
|
16
|
Waller BF, Orr CM, VanTassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part VI. Clin Cardiol 1997; 20:153-60. [PMID: 9034645 PMCID: PMC6655806 DOI: 10.1002/clc.4960200213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/1996] [Accepted: 06/20/1996] [Indexed: 02/03/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part VI of this six-part series focuses on atherectomy and restenosis tissue obtained by atherectomy procedures.
Collapse
|
17
|
Waller BF, Orr CM, Van Tassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part V. Clin Cardiol 1997; 20:67-74. [PMID: 8994741 PMCID: PMC6655373 DOI: 10.1002/clc.4960200114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/1996] [Accepted: 06/27/1996] [Indexed: 02/03/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed "remodeling." Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (< or = 1 year) and old (> 1 year) saphenous vein bypass grafts.
Collapse
|
18
|
Waller BF, Orr CM, VanTassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part IV. Clin Cardiol 1996; 19:960-6. [PMID: 8957601 DOI: 10.1002/clc.4960191212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part IV of this six-part series focuses on morphologic correlates of coronary angiographic patterns of remodeling after balloon angioplasty and discusses effects of angioplasty on adjacent, nondilated vessels.
Collapse
|
19
|
Waller BF, Orr CM, VanTassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: A review of histologic findings after various interventional procedures--Part III. Clin Cardiol 1996; 19:895-901. [PMID: 8914785 DOI: 10.1002/clc.4960191111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part III of this six-part series focuses on intimal proliferation and chronic recoil in patients undergoing previous remodeling techniques by balloon angioplasty.
Collapse
|
20
|
Waller BF, Fry ET, Peters TF, Hermiller JB, Orr CM, VanTassel J, Pinkerton CA. Abrupt (< 1 day), acute (< 1 week), and early (< 1 month) vessel closure at the angioplasty site. Morphologic observations and causes of closure in 130 necropsy patients undergoing coronary angioplasty. Clin Cardiol 1996; 19:857-68. [PMID: 8914779 DOI: 10.1002/clc.4960191105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
While abundant clinical and angiographic data are available regarding features of acute or abrupt closure at the site of balloon angioplasty, little morphologic information is available. This study discusses morphologic-histologic causes for acute closure after angioplasty in 130 necropsy patients. Intimal-medial flaps, elastic recoil, and primary thrombosis were the three leading morphologic causes for closure. Data were subdivided into time categories: abrupt (< 1 day), acute (< 1 week), and early (< 1 month). Intimal-medial flaps remained the most common cause for angioplasty closure despite time from angioplasty to documented occlusion. Morphologic recognition of types and frequencies of angioplasty closure are discussed, and specific mechanical, pharmacologic, or combined treatments are reviewed.
Collapse
|
21
|
Waller BF, Orr CM, VanTassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part II. Clin Cardiol 1996; 19:817-23. [PMID: 8896915 DOI: 10.1002/clc.4960191011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part II of this six-part series focuses on morphologic causes of acute closure after remodeling and discusses findings late after successful balloon angioplasty remodeling.
Collapse
|
22
|
Waller BF, Orr CM, VanTassel J, Peters T, Fry E, Hermiller J, Grider LD. Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part I. Clin Cardiol 1996; 19:744-8. [PMID: 8874995 DOI: 10.1002/clc.4960190913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part I of this six-part series focuses on mechanisms of remodeling after various interventional techniques, particularly balloon angioplasty.
Collapse
|
23
|
Hermiller JB, Fry ET, Peters TF, Orr CM, Van Tassel J, Waller B, Pinkerton CA. Late coronary artery stenosis regression within the Gianturco-Roubin intracoronary stent. Am J Cardiol 1996; 77:247-51. [PMID: 8607402 DOI: 10.1016/s0002-9149(97)89387-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The late angiographic outcome of the Gianturco-Roubin intracoronary stent has not been well defined. To investigate serial changes within the stent, we studied 23 patients (15 men and 8 women, median age 63) who had late angiographic follow-up ( > 1 year) after undergoing Gianturco-Roubin stenting for angioplasty-associated acute or threatened native coronary artery closure. Coronary angiography before and after stenting, at 6-month follow-up, and at late return was analyzed with quantitative coronary angiography. The median time from stent deployment to late angiographic follow-up was 27 months. As expected, stenting significantly increased the median minimal lumen diameter (MLD) acutely from 1.0 to 2.46 mm. Median percent diameter stenosis decreased from 66% to 18%. Although at 6 months there was a significant loss of the acute gain (median MLD decreased from 2.46 to 1.9 mm), with a corresponding increase in percent stenosis from 18% to 31%, late angiography demonstrated lesion regression, median MLD increasing from 1.9 to 2.15 mm (p = 0.004), and percent stenosis decreasing from 31% to 21% (p = 0.0026). No patient had a significant decline in minimal lesion diameter, and 5 patients had a > 50% increase in MLD at late follow-up. Linear regression analysis of 6-month MLD and late lumen gain suggested that lesions with the greatest regression were those with the lowest lumen diameters at 6-month angiography. Late angiographic analysis demonstrated significant lesion regression within the Gianturco-Roubin stent, which was sometimes dramatic. In suggesting that coronary arteriography at 6 months may underestimate the late angiographic benefit of intracoronary stenting, these data have important clinical implications, and imply that patients with a stable clinical course and angiographic stent restenosis may often be followed rather than routinely redilated.
Collapse
|
24
|
Fry ET, Hermiller JB, Peters TF, Orr CM, VanTassel J, Waller BF, Pinkerton CA. Indications for and applications of the Gianturco-Roubin coronary stent. Cardiol Clin 1994; 12:631-49. [PMID: 7850834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Gianturco-Roubin coronary stent is approved for and effective in the management of acute or threatened closure after unsuccessful coronary intervention. Factors critical to successful stenting include patient and lesion selection, preprocedure identification of patients in potential need of stenting, selection of stent-compatible ancillary equipment, appropriate antiplatelet and anticoagulant therapy, postdeployment stent dilatation, and careful sizing of stents. Further refinements of technique and adjunctive drug therapy should continue to improve results and avoid acute complications. Published clinical experience and potential future applications are discussed.
Collapse
|
25
|
Waller BF, Orr CM, Slack JD, Pinkerton CA, Van Tassel J, Peters T. Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part IV. Clin Cardiol 1992; 15:675-87. [PMID: 1395203 DOI: 10.1002/clc.4960150911] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In the last 15 years, intense interest has focused on various interventional pharmacologic and mechanical forms of therapy for the treatment of atherosclerosis coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part IV of this review will focus on congenital coronary artery anomalies, myocardial bridges, coronary aneurysm, emboli, and dissection and clinical implications regarding echocardiographic imaging techniques.
Collapse
|