Gale Encyclopedia of Medicine Vol 5 (T Z) pdf

  GALE The

  

ENCYCLOPEDIA

M EDICINE of

SECOND EDITION

  The GALE

ENCYCLOPEDIA

of

  M EDICINE

SECOND EDITION

J A C Q U E L I N E L . L O N G E , E D I T O R

  

D E I R D R E S . B L A N C H F I E L D , A S S O C I A T E E D I T O R

  

V O L U M E

T-Z

  

ORGANIZATIONS

GENERAL INDEX

  

5

  STAFF Jacqueline L. Longe, Project Editor Deirdre S. Blanchfield, Associate Editor Christine B. Jeryan, Managing Editor Donna Olendorf, Senior Editor Stacey Blachford, Associate Editor Kate Kretschmann, Melissa C. McDade, Ryan

  Since this page cannot legibly accommodate all copyright notices, the acknowledgments constitute an extension of the copyright notice. While every effort has been made to ensure the reliability of the infor- mation presented in this publication, the Gale Group neither guarantees the accuracy of the data contained herein nor assumes any responsibili- ty for errors, omissions or discrepancies. The Gale Group accepts no payment for listing, and inclusion in the publication of any organiza- tion, agency, institution, publication, service, or individual does not imply endorsement of the editor or publisher. Errors brought to the attention of the publisher and verified to the satisfaction of the publish- er will be corrected in future editions. This book is printed on recycled paper that meets Environmental Pro- tection Agency standards. The paper used in this publication meets the minimum requirements of American National Standard for Information Sciences-Permanence Paper for Printed Library Materials, ANSI Z39.48-1984. This publication is a creative work fully protected by all applicable copyright laws, as well as by misappropriation, trade secret, unfair com- petition, and other applicable laws. The authors and editor of this work have added value to the underlying factual material herein through one or more of the following: unique and original selection, coordination, expression, arrangement, and classification of the information. Gale Group and design is a trademark used herein under license. All rights to this publication will be vigorously defended. Copyright © 2002 Gale Group 27500 Drake Road Farmington Hills, MI 48331-3535 All rights reserved including the right of reproduction in whole or in part in any form.

  2001051245

  II. Blanchfield, Deirdre S. III. Gale Research Company. RC41.G35 2001 616’.003—dc21

  1. Internal medicine—Encyclopedias. I. Longe, Jacqueline L.

  ISBN 0-7876-5489-2 (set: hardcover) — ISBN 0-7876-5490-6 (vol. 1) — ISBN 0-7876-5491-4 (vol. 2) — ISBN 0-7876-5492-2 (vol. 3) — ISBN 0-7876-5493-0 (vol. 4) — ISBN 0-7876-5494-9 (vol. 5)

  Library of Congress Cataloging-in-Publication Data Gale encyclopedia of medicine / Jacqueline L. Longe, editor; Deirdre S. Blanchfield, associate editor — 2nd ed. p. cm. Includes bibliographical references and index. Contents: Vol. 1. A-B — v. 2. C-F — v. 3. G-M — v. 4. N-S — v. 5. T-Z.

  ISBN 0-7876-5489-2 (set) 0-7876-5490-6 (Vol. 1) 0-7876-5491-4 (Vol. 2) 0-7876-5492-2 (Vol. 3) 0-7876-5493-0 (Vol. 4) 0-7876-5494-9 (Vol. 5) Printed in the United States of America 10 9 8 7 6 5 4 3 2 1

  ENCYCLOPEDIA of MEDICINE

SECOND EDITION

  Thomason, Assistant Editors Mark Springer, Technical Specialist Andrea Lopeman, Programmer/Analyst Barbara J. Yarrow, Manager, Imaging and Multimedia

  Dorothy Maki, Manufacturing Manager Wendy Blurton, Senior Manufacturing Specialist The GALE

  Electronic Prepress Evi Seoud, Assistant Manager, Composition Purchasing and Electronic Prepress

  Image Catalogers Pamela A. Reed, Imaging Coordinator Randy Bassett, Imaging Supervisor Robert Duncan, Senior Imaging Specialist Dan Newell, Imaging Specialist Christine O’Bryan, Graphic Specialist Maria Franklin, Permissions Manager Margaret A. Chamberlain, Permissions Specialist Michelle DiMercurio, Senior Art Director Mike Logusz, Graphic Artist Mary Beth Trimper, Manager, Composition and

  Multimedia Content Kelly A. Quin, Editor, Imaging and Multimedia Content Leitha Etheridge-Sims, Mary K. Grimes, Dave Oblender,

  Multimedia Content Dean Dauphinais, Senior Editor, Imaging and

  Content Robyn V. Young, Project Manager, Imaging and

  

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Advisory Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

Entries

  

Volume 1: A-B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

  1 Volume 2: C-F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625

Volume 3: G-M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1375

Volume 4: N-S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2307

Volume 5: T-Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3237

  

Organizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3603

General Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3625

CONTENTS The Gale Encyclopedia of Medicine 2 is a medical ref- erence product designed to inform and educate readers about a wide variety of disorders, conditions, treatments, and diagnostic tests. The Gale Group believes the product to be comprehensive, but not necessarily definitive. It is intended to supplement, not replace, consultation with a physician or other healthcare practitioner. While the Gale Group has made substantial efforts to provide information that is accurate, comprehensive, and up-to-date, the Gale Group makes no representations or warranties of any kind, including without limitation, warranties of mer- chantability or fitness for a particular purpose, nor does it guarantee the accuracy, comprehensiveness, or timeliness of the information contained in this product. Readers should be aware that the universe of medical knowledge is constantly growing and changing, and that differences of medical opinion exist among authorities. Readers are also advised to seek professional diagnosis and treatment for any medical condition, and to discuss information obtained from this book with their health care provider.

  

PLEASE READ—IMPORTANT INFORMATION

  

INTRODUCTION

INCLUSION CRITERIA

ABOUT THE CONTRIBUTORS

  The Gale Encyclopedia of Medicine 2 has been designed with ready reference in mind.

  The essays were compiled by experienced medical writers, including physicians, pharmacists, nurses, and other health care professionals. GEM2 medical advisors reviewed the completed essays to insure that they are appropriate, up-to-date, and medically accurate.

  A preliminary list of diseases, disorders, tests and treat- ments was compiled from a wide variety of sources, including professional medical guides and textbooks as well as consumer guides and encyclopedias. The general advisory board, made up of public librarians, medical librarians and consumer health experts, evaluated the top- ics and made suggestions for inclusion. The list was sorted by category and sent to GEM2 medical advisors, certified physicians with various medical specialities, for review. Final selection of topics to include was made by the med- ical advisors in conjunction with the Gale Group editor.

  Alternative treatment sections for diseases and condi- tions that may be helped by complementary therapies.

  The Gale Encyclopedia of Medicine 2 (GEM2) is a one-stop source for medical information on nearly 1,700 common medical disorders, conditions, tests, and treat- ments, including high-profile diseases such as AIDS, Alzheimer’s disease, cancer, and heart attack. This ency- clopedia avoids medical jargon and uses language that laypersons can understand, while still providing thor- ough coverage of each topic. The Gale Encyclopedia of

  Disorders/Conditions Tests/Treatments

  Definition Definition Description Purpose Causes and symptoms Precautions Diagnosis Description Treatment Preparation Alternative treatment Aftercare Prognosis Risks Prevention Normal/Abnormal results Resources Resources Key terms Key terms

  Many common drugs are also covered, with generic drug names appearing first and brand names following in parentheses, eg. acetaminophen (Tylenol). Throughout the Gale Encyclopedia of Medicine 2, many prominent individuals are highlighted as sidebar biographies that accompany the main topical essays. Articles follow a standardized format that provides information at a glance. Rubrics include:

  Gale Encyclopedia of Medicine 2 , including disorders/ conditions, tests/procedures, and treatments/therapies.

  Almost 1,700 full-length articles are included in the

  SCOPE

  fills a gap between basic consumer health resources, such as single-volume family medical guides, and highly technical professional materials.

  Medicine 2

HOW TO USE THIS BOOK

• Straight alphabetical arrangement allows users to locate information quickly.
• Bold-faced terms function as

  print hyperlinks that point the reader to related entries in the encyclopedia.

  In recent years there has been a resurgence of interest in holistic medicine that emphasizes the connection between mind and body. Aimed at achieving and main- taining good health rather than just eliminating disease, this approach has come to be known as alternative medi- cine. The Gale Encyclopedia of Medicine 2 includes a number of essays on alternative therapies, ranging from traditional Chinese medicine to homeopathy and from meditation to aromatherapy. In addition to full essays on alternative therapies, the encyclopedia features specific

  Cross-references placed throughout the encyclopedia Resources section directs users to additional sources

• direct readers to where information on subjects with- of medical information on a topic. out entries can be found. Synonyms are also cross-ref-
• A comprehensive general index allows users to easily

  oduction erenced.

  target detailed aspects of any topic, including Latin

  Intr names.

• A list of key terms are provided where appropriate to define unfamiliar terms or concepts.

  GRAPHICS

• Valuable contact information for organizations and support groups is included with each entry. The The Gale Encyclopedia of Medicine 2 is enhanced appendix contains an extensive list of organizations with over 675 color images, including photos, charts, arranged in alphabetical order. tables, and customized line drawings.

  MEDICAL ADVISORS

  Elizabeth Clewis Crim, MLS Collection Specialist

  Tufts University School of Medicine Boston, MA

  Lecturer on Psychiatry

  Harvard Medical School Cambridge, MA Lee A. Shratter, M.D.

  Staff Radiologist

  The Permanente Medical Group Richmond, CA Amy B. Tuteur, M.D.

  Sharon, MA

  LIBRARIAN ADVISORS Maureen O. Carleton, MLIS Medical Reference Specialist

  King County Library System Bellevue, WA

  Prince William Public Library, VA

  Philadelphia, PA Ronald Pies, M.D.

  Valerie J. Lawrence, MLS Assistant Librarian

  Western States Chiropractic College

  Portland, OR

  Barbara J. O’Hara, MLS Adult Services Librarian

  Free Library of Philadelphia, PA

  Alan M. Rees, MLS Professor Emeritus

  Case Western Reserve University Cleveland, OH

  

ADVISORY BOARD

  Clinical Professor of Psychiatry

  Medical College of Pennsylvania– Hahnemann University

  A. Richard Adrouny, M.D., F.A.C.P.

  Msc.Psych., MRSNZ FRSH, FRIPHH, FAIC, FZS DAPA, DABFC, DABCI

  Clinical Assistant Professor of Medicine

  Division of Oncology Stanford University

  Director of Medical Oncology

  Community Hospital of Los Gatos- Saratoga

  Los Gatos, CA Laurie Barclay, M.D. Neurological Consulting Services Tampa, FL Kenneth J. Berniker, M.D.

  Attending Physician

  Emergency Department Kaiser Permanente Medical Center Vallejo, CA Rosalyn Carson-DeWitt, M.D.

  Durham, NC Robin Dipasquale, N.D. Clinical Faculty Bastyr University Seattle, WA Faye Fishman, D.O. Randolph, NJ J. Gary Grant, M.D. Pacific Grove, CA Laith F. Gulli, M.D. M.Sc., M.Sc.(MedSci), MSA,

  Consultant Psychotherapist in Private Practice

  Clinical Professor of Medicine

  Lathrup Village, MI L. Anne Hirschel, D.D.S. Southfield, MI

Larry I. Lutwick M.D., F.A.C.P.

  Director, Infectious Diseases

  VA Medical Center Brooklyn, NY

  Ira Michelson, M.D., M.B.A., F.A.C.O.G.

  

Physician and Clinical Instructor

  University of Michigan Ann Arbor, MI Susan Mockus, M.D.

  Scientific Consultant

  Seattle, WA

  Ralph M. Myerson, M.D., F.A.C.P.

  A number of experts in the library and medical communities provided invaluable assistance in the formulation of this ency- clopedia. Our advisory board performed a myriad of duties, from defining the scope of coverage to reviewing individual entries for accuracy and accessibility. The editor would like to express her appreciation to them.

  Margaret Alic, Ph.D.

  Medical Writer

  Genetic Counselor

  Eugene, OR

  Barbara Boughton Health and Medical Writer

  El Cerrito, CA Cheryl Branche, M.D.

  Retired General Practitioner

  Jackson, MS

  Michelle Lee Brandt Medical Writer

  San Francisco, CA Maury M. Breecher, Ph.D.

  Health Communicator/Journalist

  Northport, AL

  Ruthan Brodsky Medical Writer

  Bloomfield Hills, MI Tom Brody, Ph.D.

  Science Writer

  Berkeley, CA Leonard C. Bruno, Ph.D.

  Chevy Chase, MD

  Genetic Counselor

  Diane Calbrese Medical Sciences and Technology Writer

  Silver Spring, Maryland

  Richard H. Camer Editor International Medical News Group

  Silver Spring, MD Rosalyn Carson-DeWitt, M.D.

  Medical Writer

  Durham, NC Lata Cherath, Ph.D.

  Science Writing Intern Cancer Research Institute

  New York, NY

  Linda Chrisman Massage Therapist and Educator

  Oakland, CA Lisa Christenson, Ph.D.

  Science Writer

  Hamden, CT Geoffrey N. Clark, D.V.M.

  Editor Canine Sports Medicine Update

  Newmarket, NH

  Children’s Hospital Oakland Oakland, CA

Michelle Q. Bosworth, M.S., C.G.C.

  Jennifer Bowjanowski, M.S., C.G.C.

  Science Writer

  North York, Ontario Laurie Barclay, M.D.

  Eastsound, WA

  Janet Byron Anderson Linguist/Language Consultant

  Rocky River, OH Lisa Andres, M.S., C.G.C.

  Certified Genetic Counselor and Medical Writer

  San Jose, CA

  Greg Annussek Medical Writer/Editor

  New York, NY Bill Asenjo, M.S., C.R.C.

  Science Writer

  Iowa City, IA Sharon A. Aufox, M.S., C.G.C.

  Genetic Counselor

  Rockford Memorial Hospital Rockford, IL

  Sandra Bain Cushman Massage Therapist, Alexander Technique Practitioner

  Charlottesville, VA

  Howard Baker Medical Writer

  Neurological Consulting Services

  Atlanta, GA

  Tampa, FL

  Jeanine Barone Nutritionist, Exercise Physiologist

  New York, NY

  Julia R. Barrett Science Writer

  Madison, WI Donald G. Barstow, R.N.

  Clincal Nurse Specialist

  Oklahoma City, OK Carin Lea Beltz, M.S.

  Genetic Counselor and Program Director

  The Center for Genetic Counseling Indianapolis, IN Linda K. Bennington, C.N.S.

  Science Writer

  Virginia Beach, VA

  Issac R. Berniker Medical Writer

  Vallejo, CA Kathleen Berrisford, M.S.V.

  Science Writer Bethanne Black Medical Writer

  

CONTRIBUTORS

  Rhonda Cloos, R.N.

  Maureen Haggerty Medical Writer

  Medical Writer

  Medical Ink St. Paul, MN Karen Ericson, R.N.

  Altha Roberts Edgren Medical Writer

  University of Arizona Tucson, AZ

  Thomas Scott Eagan Student Researcher

  Asheville, NC

  Clare Hanrahan Medical Writer

  Ambler, PA

  Winston-Salem, NC

  

L. Fleming Fallon Jr., M.D.,

Dr.PH

Associate Professor of Public

Health

  Medical Writer

  Lathrup Village, MI Kapil Gupta, M.D.

  Consultant Psychotherapist in Private Practice

  Msc.Psych, MRSNZ

  Asheville, NC Laith F. Gulli, M.D. M.Sc., M.Sc.(MedSci), M.S.A.,

  Peter Gregutt Writer

  Silver Spring, MD

  former president, American Massage Therapy Association Massage Therapist

  Estes Park, CO

  Bowling Green State University Bowling Green, OH Faye Fishman, D.O.

  Alison Grant Medical Writer

  Medical Writer

  Contributors

  New Milford, PA

  Medical Writer

  Manitowoc, WI Ron Gasbarro, Pharm.D.

  Nurse, Medical Writer

  East Rock Institute New Haven, CT Cynthia L. Frozena, R.N.

  Research and Administrative Associate

  Atlanta, GA Rebecca J. Frey, Ph.D.

  Grand Forks, ND

Sallie Freeman, Ph.D., B.S.N.

  Physician

  Janie F. Franz Writer

  Chaplin, MN

  Paula Ford-Martin Medical Writer

  Culver City, CA

  Risa Flynn Medical Writer

  Lexikon Communications Sebastopol, CA

  Janis Flores Medical Writer

  Randolph, NJ

  Averill Park, NY Elliot Greene, M.A.

  University of Michigan Ann Arbor, MI

  Medical Writer

  Physician

  Robert S. Dinsmoor Medical Writer

  Sicklerville, NJ

  Lori De Milto Medical Writer

  Mahopac, NY

  Medical Writer/Editor

  Fremont, California Dominic De Bellis, Ph.D.

  Medical Writer

  Brooklyn, NY Tish Davidson, A.M.

  Holbrook, MA Arnold Cua, M.D.

  Medical Writer

  Medical Writer

  Chicago, IL Esther Csapo Rastega, R.N., B.S.N.

  Medical Writer

  Vermillion, SD David A. Cramer, M.D.

  Medical Writer

  Sacramento, CA Amy Cooper, M.A., M.S.I.

  Gloria Cooksey, C.N.E Medical Writer

  Austin, TX

  South Hamilton, MA Stephanie Dionne, B.S.

  Ann Arbor, MI Martin W. Dodge, Ph.D.

  Senior Research Associate

  Playa del Rey, CA Gary Gilles, M.A.

  Germantown, MD Jill Granger, M.S.

  Megan Gourley Writer

  Nazareth, PA

  Debra Gordon Medical Writer

  Old Lyme, CT

  Harry W. Golden Medical Writer Shoreline Medical Writers

  Wauconda, IL

  Medical Writer

  Julie A. Gelderloos Biomedical Writer

FRSH, FRIPHH, FAIC, FZS

  Technical Writer/Editor

  Boulder, CO

  Science Writer

  Milwaukee, WI Doug Dupler, M.A.

  Genetic Counselor

  Salt Lake City, UT Stefanie B. N. Dugan, M.S.

  David Doermann Medical Writer

  Inglewood, CA

  Centinela Hospital and Medical Center

  Ann M. Haren Science Writer

  Lakewood, OH West Chester, PA

  Medical Writer

  Ossining, NY Joseph Knight, P.A.

  Bob Kirsch Medical Writer

  Havertown, PA

  Christine Kuehn Kelly Medical Writer

  Bay Village, OH

  Beth A. Kapes Medical Writer

  Liz Meszaros Medical Writer

  Melissa Knopper Medical Writer

  Montreal, Quebec

  Medical Writer and Editor

  Phoenixville, CA Alison McTavish, M.Sc.

  Mercedes McLaughlin Medical Writer

  Ann Arbor, MI

  Sally C. McFarlane-Parrott Medical Writer

  Greensboro, NC

  Medical Writer

  Winton, CA

  Chicago, IL Karen Krajewski, M.S., C.G.C.

  Fellow, American College of Surgeons Diplomat American Board of Surgery

  Jill Lasker Medical Writer

  San Diego, CA

  Medical Writer

  Huntington Beach, CA Lorraine Lica, Ph.D.

  Biological Consultant

  East Lansing, MI Victor Leipzig, Ph.D.

  Kristy Layman Music Therapist

  Midlothian, VA

  Sabin, MN

  Genetic Counselor

  Physical Therapist

  Philadelphia, PA Jeffrey P. Larson, R.P.T.

  Richard H. Lampert Senior Medical Editor W.B. Saunders Co.

  Spokane, WA

  Jennifer Lamb Medical Writer

  Pittsburgh, PA

  Physician, writer

  Assistant Professor of Neurology Wayne State University Detroit, MI Jeanne Krob, M.D., F.A.C.S.

  Richland, WA Bonny McClain, Ph.D.

  Charlottesville, VA Richard A. McCartney M.D.

  Madison, CT Judy C. Hawkins, M.S.

  Genetic Counselor

  Genetic Counselor

  The Children’s Mercy Hospital Kansas City, MO Dawn A. Jacob, M.S.

  Genetic Counselor

  Morristown, NJ Holly Ann Ishmael, M.S., C.G.C.

  Medical Writer

  Albuquerque, NM Kevin Hwang, M.D.

  University of New Mexico Health Sciences Center

  Boca Raton, FL Katherine S. Hunt, M.S.

  Medical Writer Los Angeles, CA Michelle L. Johnson, M.S., J.D.

  Lisette Hilton Medical Writer

  London, Ontario

  David Helwig Medical Writer

  New Orleans, LA

  Caroline Helwick Medical Writer

  Galveston, TX

  The University of Texas Medical Branch

  Genetic Counselor

  Obstetrix Medical Group of Texas Fort Worth, TX Sally J. Jacobs, Ed.D.

  Patent Attorney and Medical Writer

  Medical Writer

  Suzanne M. Lutwick Medical Writer

  Beloit, WI Ruth E. Mawyer, R.N.

  Medical Writer

  Demarest, NJ Adrienne Massel, R.N.

  Consultant, Molecular Pathology

  Wayne State University Detroit, MI Warren Maltzman, Ph.D.

  Medical Student

  Brooklyn, NY Nicole Mallory, M.S.

  VA Medical Center Brooklyn, NY

  Portland, OR Paul A. Johnson, Ed.M.

  Director, Infectious Diseases

  Utah State University Logan, UT Larry Lutwick, M.D., F.A.C.P.

  Assistant Director, Biotechnology Center

  Medical Writer John T. Lohr, Ph.D.

  Sagescript Communications Lakewood, CO David Kaminstein, M.D.

  Biomedical Writer

  San Diego, CA Cindy L. A. Jones, Ph.D.

  Medical Writer

  Contributors

  Betty Mishkin Medical Writer

  Medical Writer

  Division of Clinical and Metabolic Genetics

  Genetic Counselor

  Phoenix, Arizona

Nada Quercia, M.S., C.C.G.C.

  Medical Writer

  Buffalo Grove, IL Elizabeth J. Pulcini, M.S.

  Medical Writer

  Phoenix, AZ Scott Polzin, M.S., C.G.C.

  South Windsor, CT J. Ricker Polsdorfer, M.D.

  Ann Quigley Medical Writer

  Medical Writer

  Logan, UT Joyce S. Siok, R.N.

  Medical Writer

  Richmond, TX Judith Sims, M.S.

  Writer

  Center for Cancer Risk Analysis Massachusetts General Hospital Boston, MA Kim A. Sharp, M.Ln.

  Genetic Counselor

  Catherine Seeley Medical Writer Kristen Mahoney Shannon, M.S., C.G.C.

  The Hospital for Sick Children Toronto, ON, Canada

  New York, NY Robert Ramirez, B.S.

  Clinical Geneticist

  Evanston, IL

  Moorehead, KY

  Medical Writer

  

Anna Rovid Spickler, D.V.M.,

Ph.D.

  Belleville, MI

  Nancy Ross-Flanigan Science Writer

  Tucson, AZ

  Richard Robinson Medical Writer

  Martha Robbins Medical Writer

  Medical Student

  Salt Lake City, UT

  Toni Rizzo Medical Writer

  Holbrook, MA

  

Registered Nurse, Medical Writer

  

Esther Csapo Rastegari, Ed.M.,

R.N./B.S.N.

  New York, NY

  Medical Doctor and Writer

  University of Medicine & Dentistry of New Jersey Stratford, NJ Kulbir Rangi, D.O.

  Greenwood Genetic Center Greenwood, SC

  Mental Health Marlborough, MA Laurie Heron Seaver, M.D.

  Skokie, IL

  Universidad Iberoamericana Santo Domingo, Domincan

  Ute Park, NM Lisa Papp, R.N.

  Medical Writer

  Minneapolis, MN Teresa Norris, R.N.

  Nancy J. Nordenson Medical Writer

  Weehawken, NJ

  Laura Ninger Medical Writer

  Republic

  Senior Medical Student

  Cherry Hill, NJ

  Huntington Beach, CA Bilal Nasser, M.Sc.

  Louann W. Murray, PhD Medical Writer

  Milwaukee, WI

  Susan J. Montgomery Medical Writer

  Seattle, WA

  Medical Writer

  Hallstead, PA Mark A. Mitchell, M.D.

  Barbara J. Mitchell Medical Writer

  Medical Writer

  Patience Paradox Medical Writer

  Nursing Massachusetts Department of

  Medical, Science, & Technology Writer

  Joan Schonbeck Medical Writer

  Holland, OH

  Chiropractor Holland Chiropractic, Inc.

  Branford, CT Jason S. Schliesser, D.C.

  Technical Writer

  Chicago, IL Kausalya Santhanam, Ph.D.

  Karen Sandrick Medical Writer

  Los Angeles, CA

  Voorheesville, NY Andrea Ruskin, M.D. Whittingham Cancer Center Norwalk, CT Laura Ruth, Ph.D.

  Bainbridge Island, WA

  Medical Writer

  Wheaton, IL Belinda Rowland, Ph.D.

  Collette Placek Medical Writer

  Chicago, IL

  Medical Writer

  Bend, OR Genevieve Pham-Kanter, M.S.

  Genetic Counseling of Central Oregon

  Barbara J. Pettersen Genetic Counselor

  Contributors

  Jennifer Sisk Medical Writer

  East Northport, NY Catherine L. Tesla, M.S., C.G.C.

  Jennifer Wurges Medical Writer

  Rochester Hills, MI Mary Zoll, Ph.D.

  Science Writer

  Newton Center, MA

  Jon Zonderman Medical Writer

  Orange, CA Michael V. Zuck, Ph.D.

  Medical Writer

  Boulder, CO

  Liz Swain Medical Writer

  San Diego, CA

  Deanna M. Swartout-Corbeil, R.N.

  Medical Writer

  Thompsons Station, TN Keith Tatarelli, J.D.

  Medical Writer Mary Jane Tenerelli, M.S. Medical Writer

  Senior Associate, Faculty

  Medical Writer

  Lancaster, PA Judith Turner, B.S.

  Wantagh, NY

  Medical Writer

  Sharon, MA Samuel Uretsky, Pharm.D.

  Medical Advisor

  Sandy, UT Amy B. Tuteur, M.D.

  Medical Writer

  Carol Turkington Medical Writer

  Dept. of Pediatrics, Division of Medical Genetics

  Troy, MI

  Medical Writer

  Rockland, ME Mai Tran, Pharm.D.

  Bethany Thivierge Biotechnical Writer/Editor Technicality Resources

  Atlanta, GA

  Emory University School of Medicine

  Delmar, DE

  Haddonfield, NJ Kathleen D. Wright, R.N.

  Havertown, PA

  Albuquerque, NM Java O. Solis, M.S.

  Canton, OH Lorraine Steefel, R.N.

  Jane E. Spehar Medical Writer

  Little Rock, AR

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  Contributors Taeniasis see Tapeworm diseases Tagged red blood cell scan see GI bleeding studies T’ai chi Definition

  T’ai chi is a Chinese exercise system that uses slow, smooth body movements to achieve a state of relaxation of both body and mind.

  Purpose As a system of physical exercise used to improve and maintain health, t’ai chi can be helpful in achieving a state of physical and mental relaxation while also strengthening the cardiovascular system.

  Precautions As a very slow and gentle form of moving, t’ai chi has virtually no side effects. However, if a person has any doubts about the condition of his or her joints, vertebrae, or heart, a physician should be consulted.

  Description Developed originally in China as a self-defense strategy, or martial art, t’ai chi—the “supreme ultimate fist”—is practiced in modern times primarily as a gentle exercise technique. Described as “meditation in motion,” t’ai chi consists of a standing person performing a series of postures or bodily movements in a slow and graceful manner, with each movement flowing without pause to the next. According to Chinese legend, the technique was created by a Taoist monk who was inspired as he watched a crane and a snake do battle. Impressed by the snake’s ability to subtly and swiftly avoid the bird’s thrusts, he devised a series of self-defense techniques that do not involve meeting the opponent’s force with force, but rather stress evading the blow; causing the opponent’s own momentum to work against him.

  T’ai chi is an ancient form of exercise, about 2,000 years old, that at one point had over 100 separate move- ments or postures. In current practice, there are two popular versions, of 18 and 37 movements respectively. The fact that in China 10 million people practice some type of t’ai chi daily suggests that it is one of the most popular forms of exercise in the world. In the United States, t’ai chi is learned in classes in which students (or “players,” as they are called in China) wear loose, comfortable clothing and either go barefoot or wear only socks or soft shoes on the feet. In China, t’ai chi is almost always practiced outdoors at dawn, and ideally near trees. Unlike other martial arts, t’ai chi is not competitive. Classes usually begin with a few minutes of standing meditation to calm the mind and gather energy. Following warm-up exercises, students are taught the basics of a particular form or posture. Learning forms is not easy, and it takes some time to master what looks like a simple position. Properly done postures are done in a relaxed, art- ful, and linked way, with the circular and rhythmic move- ments of one position flowing seamlessly into the next.

  While strict attention to body position is critical, proper breathing is considered to be equally important. Just as movements are slow and continuous and without strain, breathing should be effortless yet deep. Finally, both mental and physical balance is considered essential to t’ai chi. The experienced practitioner of t’ai chi main- tains perfect body balance throughout the exercise series. Altogether, the five essential qualities of t’ai chi are: • Slowness. To develop awareness.

• Lightness. To make movements flow.
• Balance. To prevent body strain.
• Calmness. To maintain continuity.
• Clarity. To focus the mind.

  T’ai chi has both physical and mental benefits. If done regularly, it improves muscle tone, flexibility, balance, and

T

  K E Y T E R M S Arthritis—Inflammation of the joints. orm diseases Cardiovascular—Relating to the heart and blood w vessels. Tape Continuity—Uninterrupted and successive.

  Meditation—An exercise of contemplation that induces a temporary feeling of relaxation. Stamina—Staying power, endurance. Yoga—A system of exercise aimed at promoting the control of the body and the mind.

  falling, especially important for the elderly. T’ai chi can result in a significant improvement in the quality of life for anyone. But, because of the low stress level of the exercis- es it is a particularly attractive form of exercise to seniors.

  T’ai chi is a Chinese exercise system that uses slow, smooth body movements to achieve a state of relaxation. Resources The posture above is part of the single whip sequence of t’ai chi motions. (Illustration by Electronic Illustrators Group.)

  BOOKS T’ai Chi.

  Crompton, Paul. New York: Macmillan, 1996. coordination. Many older people find that it boosts their

  Guiness, Alma E. Family Guide to Natural Medicine. Pleas-

  energy, stamina, and agility, sharpens their reflexes, and antville, NY: The Reader’s Digest Association, Inc., 1993. gives an overall sense of well-being. The calming and Parry, Robert. T’ai Chi. Chicago: NTC Publishing Group, 1997. meditative aspects of t’ai chi allow many to experience its

  PERIODICALS

  ability to relieve stress. Some claim t’ai chi to be a healing

  Brody, Jane. “T’ai Chi Offers Gentle, Stylized Exercises.” The

  therapy, and it is often used to support other treatments for

  New York Times , 16 July 1997, C1.

  chronic conditions; arthritis and digestive disorders are

  Krucoff, Carol. “Western Science Studies Healing Effects of

  just two examples. Like yoga, t’ai chi has several different Ancient Eastern Practice.” The Washington Post, 14 Apr. styles to suit the individual. Also, it can eventually be done 1998, 28, 30. daily by oneself, and ultimately becomes a very personal

  ORGANIZATIONS

  endeavor. Most Westerners find it best to practice t’ai chi

  The Northeastern T’ai Chi Chuan Association. 163 West 23rd

  in the same place and at the same time of day, and those St., 5th Floor., New York, NY 10011 (212) 741-1922. who enjoy it most are those who are not seeking major, dramatic breakthroughs, but rather who can take pleasure Leonard C. Bruno, PhD in small gains that accumulate over a long period of time.

  Tailbone injuries see Coccyx injuries Risks

  Talipes see Clubfoot

  T’ai chi is a safe exercise system for people of all ages

  Tamoxifen see Anticancer drugs

  and fitness levels. Done properly, without any over-stretch-

  Tamponade see Cardiac tamponade ing, t’ai chi should not leave a person feeling tired or sore.

  Normal results stress reduc-

  Besides its overall fitness benefits and

  tion aspects, regular t’ai chi sessions are said to be espe- Tapeworm diseases

  cially helpful for seniors, as they lower their blood pres-

  Definition

  sure. T’ai chi claims to benefit arthritis sufferers, those recovering from an injury or rehabilitating their hearts, and Tapeworms are a group of parasitic worms that live also improves balance, and therefore, reduces the risk of in the intestinal tracts of some animals. Several different species of tapeworms can infect humans. Tapeworm dis- ease or cestodiasis occurs most commonly after eating raw or undercooked meat or fish that contains the imma- ture form of the tapeworm.

  Description

  Tapeworm infections pose a serious public health problem in many less developed countries due to poor san- itation conditions. The disease is most common where livestock, such as cattle and pigs, are raised in areas where human feces are not disposed of in a sanitary manner. Another common source of human tapeworms are certain species of freshwater fish. Tapeworm infections tend to occur more frequently in areas of the world where the peo- ple regularly eat raw or undercooked beef, pork, or fish. Persons of all ages and both sexes are susceptible to tape- worm infection, but children are generally not exposed until they are old enough to begin eating meat or fish.

  Tapeworm is less common in industrialized regions of the world, but travel to areas in which tapeworm infec- tions are more common and immigration of people from these areas serve as new sources of the parasite. Infected persons are often unaware of the presence of adult tape- worms in their intestinal tract, as they may have no obvi- ous symptoms of infection. Some tapeworms can live in an infected person for over 10 years if diagnosis is not made and treatment is not administered.

  In addition to the typical infection caused by eating undercooked meat or fish, people may also be directly infected by ingesting tapeworm eggs shed by the adult worm. This type of tapeworm infection can lead to a con- dition referred to as cysticercosis, in which the larvae continue to develop within tissues other than the intesti- nal tract. One of the most serious forms of this disease occurs when the tapeworm larvae infect the central ner- vous system, a disease referred to as neurocysticercosis. In contrast to a typical tapeworm infection, which may not be associated with symptoms, neurocysticercosis is a serious condition that may cause seizures and is poten- tially life-threatening.

  Causes and symptoms

  Several species of tapeworm can infect people. The two most common species are the pork tapeworm (Taenia

  solium ) and the beef tapeworm (Taenia saginata).

  Improperly treated human sewage may be used to fertilize pastures or crops. Pigs or cattle become infected by graz- ing in contaminated pastures or drinking water contami- nated with tapeworm eggs from human feces. The pea- sized larvae of these tapeworms are deposited in certain tissues of the body of infected pigs and cattle, including the muscles. The infection is then transmitted to people when raw or undercooked meat containing tapeworm lar- vae is consumed. The immature tapeworm develops into the adult form in the human intestine and may remain there for many years if not identified and treated.

  The Taenia tapeworms attach to the intestinal walls but cause only mild inflammation at the site of attach- ment. As a result, most tapeworm carriers show no symp- toms (asymptomatic) and usually become aware of the infection only after noticing tapeworm segments in their feces. Segments of the beef tapeworm may spontaneous- ly pass through the anus causing a noticeable sensation. Mild gastrointestinal symptoms, such as nausea or abdominal pain, can occur in infected individuals. In rare cases where the tapeworm segments migrate into the appendix, pancreas, or bile duct, there may be a sudden onset of severe abdominal discomfort.

  Cysticercosis is a potentially serious complication of