11 results
Consultation and Surgical Wait Times in Cervical Spondylotic Myelopathy
- Babak Sharifi, Greg McIntosh, Charles Fisher, W. Bradley Jacobs, Michael Johnson, Christopher S. Bailey, Sean Christie, Raphaële Charest-Morin, Jérome Paquet, Andrew Nataraj, David Cadotte, Neil Manson, Hamilton Hall, Kenneth C. Thomas, Y. Raja Rampersaud, Nicolas Dea
-
- Journal:
- Canadian Journal of Neurological Sciences / Volume 46 / Issue 4 / July 2019
- Published online by Cambridge University Press:
- 03 May 2019, pp. 430-435
-
- Article
-
- You have access Access
- HTML
- Export citation
-
Background: Cervical spondylotic myelopathy (CSM) is the leading cause of spinal cord impairment. In a public healthcare system, wait times to see spine specialists and eventually access surgical treatment for CSM can be substantial. The goals of this study were to determine consultation wait times (CWT) and surgical wait times (SWT), and identify predictors of wait time length. Methods: Consecutive patients enrolled in the Canadian Spine Outcomes and Research Network (CSORN) prospective and observational CSM study from March 2015 to July 2017 were included. A data-splitting technique was used to develop and internally validate multivariable models of potential predictors. Results: A CSORN query returned 264 CSM patients for CWT. The median was 46 days. There were 31% mild, 35% moderate, and 33% severe CSM. There was a statistically significant difference in median CWT between moderate and severe groups; 207 patients underwent surgical treatment. Median SWT was 42 days. There was a statistically significant difference in SWT between mild/moderate and severe groups. Short symptom duration, less pain, lower BMI, and lower physical component score of SF-12 were predictive of shorter CWT. Only baseline pain and medication duration were predictive of SWT. Both CWT and SWT were shorter compared to a concurrent cohort of lumbar stenosis patients (p <0.001). Conclusions: Patients with shorter duration (either symptoms or medication) and less neck pain waited less to see a spine specialist in Canada and to undergo surgical treatment. This study highlights some of the obstacles to overcome in expedited care for this patient population.
Instruments and Methods: The Resistograph and the Compressive Strength of Snow
- Charles C. Bradley
-
- Journal:
- Journal of Glaciology / Volume 7 / Issue 51 / 1968
- Published online by Cambridge University Press:
- 30 January 2017, pp. 499-506
-
- Article
-
- You have access Access
- HTML
- Export citation
-
A recent field comparison of snow strength as measured by the snow resistograph and compressive strength as measured by direct loading to failure indicates good agreement in the range 25–400 g/cm2.
The Location and Timing of Deep Slab Avalanches
- Charles C. Bradley
-
- Journal:
- Journal of Glaciology / Volume 9 / Issue 56 / 1970
- Published online by Cambridge University Press:
- 30 January 2017, pp. 253-261
-
- Article
-
- You have access Access
- HTML
- Export citation
-
Winter observations in the northern Rocky Mountains of Montana show two periods during which one may expect a collapsing snowpack and accompanying avalanches: (1) shaded and sheltered areas: December-February; (2) sunny and exposed areas: March-May. These periods appear to be linked in part to the cyclic rise and fall of strength in the basal snow layer. It is suggested that sheltered slopes are often about a half-cycle ahead of sunny slopes because sheltered slopes tend to retain the early snows which later become the critically weak basal layer on these slopes.
The role of stress concentration in slab avalanche release: comments on Dr R. A. Sommerfeld's paper
- Charles C. Bradley, Duain Bowles
-
- Journal:
- Journal of Glaciology / Volume 9 / Issue 57 / 1970
- Published online by Cambridge University Press:
- 30 January 2017, pp. 411-412
-
- Article
-
- You have access Access
- HTML
- Export citation
Instruments and Methods Comparison of the Snow Resistograph with the Ram Penetrometer
- William St. Lawrence, Charles C. Bradley
-
- Journal:
- Journal of Glaciology / Volume 12 / Issue 65 / 1973
- Published online by Cambridge University Press:
- 30 January 2017, pp. 315-321
-
- Article
-
- You have access Access
- HTML
- Export citation
-
Comparative tests of the snow resistograph with the ram penetrometer indicate that there is a high degree of correlation between the two instruments despite fundamental differences in operation. It is probable therefore that the two instruments are measuring essentially the same parameters and may be used interchangeably. The resistograph has a large advantage over the ram penetrometer, in terms of speed and ease of operation, and in its capacity to measure the strength of very weak snow.
Contributors
-
- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
-
- Book:
- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
-
- Chapter
- Export citation
Contributors
-
- By Francesco Acerbi, Ayca Akgoz, Matthew R. Amans, Ramsey Ashour, Mohammed Ali Aziz-Sultan, H. Hunt Batjer, Donnie Bell, Bernard R. Bendok, Giovanni Broggi, Morgan Broggi, Charles A. Bruno, Steven D. Chang, In Sup Choi, Omar Choudhri, Douglas J. Cook, William P. Dillon, Peter Dirks, Rose Du, Travis M. Dumont, Tarek Y. El Ahmadieh, Najib E. El Tecle, Mohamed Samy Elhammady, Paolo Ferroli, Alana M. Flexman, John C. Flickinger, Kai U. Frerichs, Sasikhan Geibprasert, Adrian W. Gelb, Y. Pierre Gobin, Bradley A. Gross, Seunggu J. Han, Tomoki Hashimoto, Juha Hernesniemi, Roberto C. Heros, Steven W. Hetts, Randall T. Higashida, Joshua A. Hirsch, Nikolai J. Hopf, L. Nelson Hopkins, Maziyar A. Kalani, M. Yashar S. Kalani, Hideyuki Kano, Syed Aftab Karim, Robert M. Koffie, Douglas S. Kondziolka, Timo Krings, Aki Laakso, Giuseppe Lanzino, Michael T. Lawton, Elad I. Levy, L. Dade Lunsford, Adel M. Malek, Michael P. Marks, George A. C. Mendes, Philip M. Meyers, Jacques Morcos, Nitin Mukerji, Christian Musahl, Ludmila Pawlikowska, Matthew B. Potts, Ross Puffer, James D. Rabinov, Jonathan J. Russin, Mina G. Safain, Duke Samson, Marco Schiariti, R. Michael Scott, Jason P. Sheehan, Paul Singh, Edward R. Smith, Scott G. Soltys, Robert F. Spetzler, Gary K. Steinberg, Philip E. Stieg, Hua Su, Karel terBrugge, Kiron Thomas, Tarik Tihan, Babu Welch, Jonathan White, H. Richard Winn, Chun-Po Yen, Jacky T. Yeung, Byron Yip, Samer G. Zammar
- Edited by Robert F. Spetzler, Douglas S. Kondziolka, Randall T. Higashida, University of California, San Francisco, M. Yashar S. Kalani
-
- Book:
- Comprehensive Management of Arteriovenous Malformations of the Brain and Spine
- Published online:
- 05 January 2015
- Print publication:
- 08 January 2015, pp x-xiv
-
- Chapter
- Export citation
Contributors
-
- By Yohance M. Allette, Christophe Altier, Charles E. Argoff, Nadine Attal, Paul J. Austin, Didier Bouhassira, Ian Carroll, Kristine M. Chapman, Stephen Coleman, Lynn Kerene Cooper, Michael R. Due, Mary-Ann Fitzcharles, Robyn Flynn, Andrea D. Furlan, Vishal Gupta, Maija Haanpää, Jennifer Hah, Steven H. Horowitz, John Hughes, Mark R. Hutchinson, Scott Jarvis, Maan Kattan, Manpreet Kaur, Bradley J. Kerr, Krishna Kumar, Yuen Hei Kwok, Wojciech Leppert, Liang Liu, Angela Mailis-Gagnon, Gila Moalem-Taylor, Dwight E. Moulin, Harsha Nagaraja, Dontese Nicholson, Lauren Nicotra, Anne Louise Oaklander, John Xavier Pereira, Syed Rizvi, Stephan A. Schug, Michael Serpell, Amanda Sherwin, Howard S. Smith, Peter A. Smith, Pam Squire, Peter A. Ste-Marie, Patrick L. Stemkowski, Nicole M. Sumracki, Cory Toth, Krista van Steeg, Jan H. Vranken, Bharati Vyawahare, Mark A. Ware, Linda R. Watkins, C. Peter N. Watson, Fletcher A. White
- Edited by Cory Toth, Dwight E. Moulin
-
- Book:
- Neuropathic Pain
- Published online:
- 05 December 2013
- Print publication:
- 07 November 2013, pp vii-x
-
- Chapter
- Export citation
Contributors
-
- By Jon G. Allen, Robert F Anda, Susan L. Andersen, Carl M. Anderson, Wendy d’ Andrea, Tal Astrachan, Anthony W. Bateman, Carla Bernardes, Renato Borgatti, Bekh Bradley, J. Douglas Bremner, John Briere, Amy F. Buckley, Jean-Francois Bureau, Kathleen M. Chard, Dennis Charney, Anthony Charuvastra, Jeewook Choi, Marylene Cloitre, Melody D. Combs, Constance J. Dalenberg, Martin J. Dorahy, Michael D. De Bellis, Anne P. DePrince, Erin C. Dunn, Vincent J. Felitti, Philip A. Fisher, Peter Fonagy, Julian D. Ford, Amit Goldenberg, Megan R. Gunnar, Udi Harari, Felicia Heidenreich, Christine Heim, Judith Herman MD, Monica Hodges, Shlomit Jacobson-Pick, Joan Kaufman, Karestan C. Koenen, Ruth A. Lanius, Jamie L. LaPrairie, Alicia F. Lieberman, Richard J. Loewenstein, Sonia J. Lupien MD, Karlen Lyons-Ruth, Jodi Martin, Bruce McEwen, Alexander C. McFarlane, Rosario Montirosso, Charles B. Nemeroff, Pat Ogden, Fatih Ozbay, Clare Pain, Kelsey Paulson, Oxana G. Palesh, Ms. Keren Rabi, Gal Richter-Levin, Andrea L. Roberts, Cécile Rousseau, Cécile Rousseau, Monica Ruiz-Casares, Christian Schmahl, Allan N. Schore, Sally B. Seraphin, Vansh Sharma, Yi-Shin Sheu, Kelly Skelton, Steven Southwick, David Spiegel, Deborah M. Stone, Nathan Szajnberg, Martin H. Teicher, Akemi Tomoda, Ed Tronick, Onno van der Hart, Bessel van der Kolk, Eric Vermetten, Tamara Weiss, Victor Welzant
- Edited by Ruth A. Lanius, University of Western Ontario, Eric Vermetten, Universiteit Utrecht, The Netherlands, Clare Pain, University of Toronto
-
- Book:
- The Impact of Early Life Trauma on Health and Disease
- Published online:
- 03 May 2011
- Print publication:
- 05 August 2010, pp vii-xii
-
- Chapter
- Export citation
List of Contributors
-
- By Ralph Adolphs, Bernard J. Baars, John A. Bargh, Jesse M. Bering, David F. Bjorklund, Joseph E. Bogen, Rebekah Bradley, Wallace Chafe, Michael C. Corballis, Diego Cosmelli, Jean-Marie Danion, Richard J. Davidson, Steven W. Day, Georges Dreyfus, John D. Dunne, Stan Franklin, Helena Hong Gao, Lisa Geraci, Deborah E. Hannula, J. Allan Hobson, Caroline Huron, John F. Kihlstrom, Asher Koriat, Uriah Kriegel, Jean-Philippe Lachaux, Charles D. Laughlin, Antoine Lutz, Drew McDermott, Katharine McGovern, Keith Oately, Suparna Rajaram, Henry L. Roediger III, Edmund T. Rolls, Daniel L. Schachter, William Seager, Daniel J. Simons, Scott D. Slotnick, Henry Stapp, Petra Stoerig, Ron Sun, Evan Thompson, C. Jason Throop, Rebecca Todd, Carlo Umiltà, David E. Warren, Joel Weinberger, Drew Westen, Dan Zahavi, Philip David Zelazo
- Edited by Philip David Zelazo, University of Toronto, Morris Moscovitch, University of Toronto, Evan Thompson, University of York
-
- Book:
- The Cambridge Handbook of Consciousness
- Published online:
- 05 June 2012
- Print publication:
- 14 May 2007, pp -
-
- Chapter
- Export citation
Analysis of herbal teas made from the leaves of comfrey (Symphytum officinale): reduction of N-oxides results in order of magnitude increases in the measurable concentration of pyrrolizidine alkaloids
- Nicholas H Oberlies, Nam-Cheol Kim, Dolores R Brine, Bradley J Collins, Robert W Handy, Charles M Sparacino, Mansukh C Wani, Monroe E Wall
-
- Journal:
- Public Health Nutrition / Volume 7 / Issue 7 / October 2004
- Published online by Cambridge University Press:
- 02 January 2007, pp. 919-924
-
- Article
-
- You have access Access
- Export citation
-
Objectives:
To determine the relative quantities of two hepatotoxic pyrrolizidine alkaloids, symphytine and echimidine, in teas prepared from comfrey leaves (Symphytum officinale), and to determine the potential contribution of the N-oxide forms of these alkaloids to levels of the parent alkaloids.
Design:Comfrey leaves were purchased from three commercial sources and used to prepare tea in a manner consistent with the methods used by consumers. An extraction scheme was devised for extraction of the alkaloids, and a gas chromatographic method was developed to quantify the two major alkaloids, symphytine and echimidine. Recognising that the N-oxide derivatives of these alkaloids have also been identified in comfrey preparations, chemical reduction was applied to determine the total quantities of the alkaloids as free bases and as N-oxide derivatives.
Results:The concentration of symphytine and echimidine varied considerably between teas prepared from leaves purchased from the different vendors of plant material. Moreover, a much higher concentration of symphytine was found in the tea when steps were included to reduce N-oxides prior to analysis. The treatment of pure symphytine with hot water did not generate the N-oxide derivative de novo.
Conclusions:Since the pyrrolizidine alkaloids are known to be hepatotoxic, consumption of herbal teas made from comfrey leaves may be ill-advised. The concentration of pyrrolizidine alkaloids in such teas may be underestimated substantially unless the concentration of N-oxides is taken into consideration.