Veterinary Medical Specialization: Bridging Science and Medicine

306 Pages·1995·3.196 MB·1-303\306

by  W. Jean Dodds (Eds.)

Advances in Veterinary Science
dna Comparative Medicine
Edited by
Dr. W. Jean Dodds
HEMOPET
Santa Monica, California
Advisory Board
Kenneth C. Bove(
William S. Dernell
Carlton Gyles
Robert .O Jacoby
Ann B. Kier
Raymond F. Nachreiner
Carl A. Osborne
Fred .W Quimby
Alan H. Rebar
Ronald D. Schultz
CONTRIBUTORS
Numbers ni parentheses indicate the pages no which the authors' begin. contributions
NWAD .M BOOTHE, Department of Veterinary Physiology and Phar-
macology, College of Veterinary Medicine, Texas A&M University,
College Station, Texas 77843 (191)
.W JEAN ,SDDOD Hemopet, Santa Monica, California 90403 ,1( )92
EGROEG .M HAPP, Department of Biology, University of Vermont,
Burlington, Vermont 05405 (97)
NOTNILC .D PORHTOL JR., Scott-Ritchey Research Center and Depart-
ment of Small Animal Surgery, College of Veterinary Medicine,
Auburn University, Auburn, Alabama 36849 (141)
TERAGRAM .R SLATER, Department of Veterinary Anatomy and Public
Health, College of Veterinary Medicine, Texas A&M University,
College Station, Texas 77843 (191)
JERROLD TANNENBAUM, Department of Environmental Studies, Tufts
University School of Veterinary Medicine, North Grafton, Massa-
chusetts 01536 (254)
vii
PREFACE
This volume is the first of the series for which I am privileged to
serve in the capacity of Series Editor. The subject, veterinary medical
specialization, is the bridge between practicing clinical veterinarians
and academic scientists that generates new knowledge to further the
art of veterinary medicine. Of course, much of the scientific discovery
that benefits animal medicine is derived from the basic and applied
sciences with the original purpose of benefitting human health. This
often includes biomedical research on animals along with in vitro al-
ternatives to animal testing. Much of the information gathered from
the biomedical research effort can be applied equally to human and
veterinary medicine.
It is not surprising that the veterinary profession has evolved a
series of subspecialties over the past two decades that parallels special-
ization in human medicine. This follows the explosion of knowledge in
basic science and medicine from the 1960s to the era of molecular
biology and gene therapy we have entered today. My own career, which
spans 30 years, attests to this change. As a biomedical scientist who
developed an interest and expertise in comparative hemostasis, I have
seen the field develop from a clinical specialty with rather unsophisti-
cated techniques for manually monitoring whole blood coagulation
activity in glass and silicone-coated test tubes to the most advanced
applications of biochemical and molecular techniques. Today, scien-
tists working in academia and private industry are cloning the genes
that produce individual coagulation factors and sequencing the gene
products. They can even manipulate experimental animals through
gene therapy to correct inherited bleeding disorders. Coagulation fac-
tor concentrates are routinely produced by recombinant technology for
treatment of diseases such as hemophilia to avoid the serious risk of
transfusion-transmitted disease associated with the use of blood plas-
ma concentrates.
oT be able to see a particular medical specialty evolve during my
career has been a stimulating and challenging experience. During this
time, scientific advances in hemostasis research have been translated
xi
x PREFACE
into clinical benefits such that the diagnosis, management, and treat-
ment of bleeding diseases in both human and veterinary medicine
have advanced considerably. In veterinary medicine today, blood com-
ponents available for treating animals with bleeding disorders include
packed red blood cells, fresh-frozen plasma, platelet-rich plasma, and
cryoprecipitate. Perhaps the most gratifying experience for me person-
ally has been a growing awareness of the value of all sentient life,
which evolved from an appreciation of the fact that one can pursue a
fruitful biomedical research career without undertaking invasive ex-
perimentation on animals. These studies focused on animals born with
naturally occurring genetic defects to learn more about the biochemis-
try and pathophysiology of their disorders, develop new diagnostic
tests for clinical diagnosis and research investigations, and perfect
better treatment methods to prevent and control the disorders. The
current interest in identifying and screening for genetic diseases in
veterinary medicine is exemplified by this research effort. eW have
entered a time of great promise in applying molecular techniques and
genetic engineering to correcting many animal and human diseases.
The present volume reviews the historical, current, and future needs
for specialization in the veterinary profession, discusses the emerging
importance of appropriate informed consent for all clinical and experi-
mental trials, and deals with veterinary medical ethics as applied to
specialization in clinical medicine. I thank authors Clinton Lothrop,
Dawn Boothe and Margaret Slater, and Jerrold Tannenbaum for their
insightful contributions to these subjects. My own chapter reviews
current information from health surveys and genetic screening of se-
lected dog breeds for inherited and other diseases, and George Happ
presents a timely review of autoimmune thyroiditis as a model canine
autoimmune disease. Thyroid disease is considered by veterinarians
and purebred dog fanciers to be a major problem of increasing preva-
lence, as well as an area of my own special interest. It is hoped that
basic research into the mechanisms of thyroid disease and dysfunction
in the dog will provide more insight into the equivalently common
hyperthyroid disorder of the cat.
W. JEAN DODDS
SECNAVDA NI YRANIRETEV ECNEICS DNA EVITARAPMOC ,ENICIDEM .LOV 93
Overview: Bridging Basic Science
and Clinical Medicine
.W JEAN DODDS
Hemopet, Santa Monica, California 90403
I. Background
A. Basic and Applied Animal Research
B. Early Practices
II. Emergence of Veterinary Medical Specialization
A. Introduction
B. Scientific Advances
C. Health Surveys and Genetic Screening
D. Nutrition and the Immune System
E. Medical and Legal Aspects of Clinical Trials
III. Recommendations for the Future
A. Integrating Basic and Clinical Research
B. Molecular Approaches and Gene Therapy
C. Strategies for Research Funding
References
I. Background
A. BASIC AND APPLIED ANIMAL RESEARCH
During the past century, advances in medical knowledge have con-
tributed not only to basic science but also to clinical medicine. With
respect to veterinary medicine, biomedical research on experimental
animal subjects along with basic science using nonanimal methods
have enhanced our understanding of the physiology and pathophysiol-
ogy of animal health and disease. Because a vast data base has been
generated from animal-based experiments designed primarily to bene-
fit human health and well-being, parallel benefits have been accorded
to animals (Dodds, 1988; Patterson et al., 1988; Wagner, 1992; Law-
rence, 1994). The research field of comparative medicine evolved from
1
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2 .w JEAN SDDOD
this perspective and was based on the study of naturally occurring or
induced animal models of human disease (Dodds, 1988; Patterson et
al., 1988). As alluded to in the Preface and discussed in the reviews by
Jolly et al. (1981), Dodds (1988), Patterson et al. (1988), and Smith
(1994), investigations of animal models have provided important basic
information about the mechanism of specific disease states, allowed for
development and improvement in diagnostic tests for these conditions,
and have led to advances in management and treatment methods. For
the past three or more decades, studies of animal disease models have
contributed significantly to the understanding of analogous human
diseases. Examples include the inherited bleeding disorders studied by
this author and others (Jolly et al., 1981; Dodds, 1988, 1989), congeni-
tal cardiac disease and inborn errors of metabolism (Patterson et al.,
1988), neuromuscular and copper storage disorders (Kramer et al.,
1981; Brewer et al., 1992), and the inherited eye diseases (Smith, 1994).
The net effect of these basic and comparative medical advances has
been to translate the findings to improve diagnostic and treatment
modalities in clinical veterinary medicine. This has fostered the devel-
opment of veterinary specialization, which brings existing knowledge
from the basic sciences and clinical human medicine to clinical veter-
inary medicine, and investigates new basic and applied research ini-
tiatives. As might be expected, the evolution of this new area has
sparked not only scientific and medical benefits but also controversy, as
the specialties have become officially recognized and a certification
process has been created to establish guidelines for the entry of new
members (Stromberg and Schneider, 1994). A more detailed look at
veterinary medical specialization can be found in the chapter by Lo-
throp in this volume.
B. YLRAE SECITCARP
Over the years, individuals with specific interests have developed
expertise in defined fields of veterinary medicine. These pioneers,
through teaching seminars at regional and national meetings, writing
scientific medical articles and textbooks, and training interns, resi-
dents, and other graduates, served as mentors for the formal definition
of veterinary medical specialties. The founders of this movement in-
cluded colleagues such as Drs. Stephen J. Ettinger, William F. Jack-
son, William J. Kay, and Robert .W Kirk. This group of esteemed col-
leagues served as a nucleus for ongoing support of the development of
specialization in veterinary medicine, and has encouraged the more
WEIVREVO 3
widespread introduction of specialists into clinical veterinary practice
(Stromberg and Schneider, 1994). Some of the first specialties to evolve
and be recognized by the American Veterinary Medical Association
were the American College of Veterinary Pathologists and American
Board of Veterinary Public Health, both in 1951 (the latter group was
renamed the American College of Veterinary Preventive Health in
1978); American College of Laboratory Animal Medicine in 1957;
American College of Veterinary Radiology in 1962; American College
of Veterinary Microbiology in 1966; and the American College of Vet-
erinary Surgeons and American Board of Veterinary Toxicology, both
in 1967 (AVMA, 1995). Since then, other specialties developed, includ-
ing those for theriogenology, ophthalmology, and veterinary internal
medicine with its subspecialties of cardiology, internal medicine, neu-
rology, veterinary medical oncology, and anesthesiology. New special-
ties continue to be added and these are approved and governed by
the American Veterinary Medical Association through the American
Board of Veterinary Specialties. (For more details on these specialties,
refer to the chapter by Lothrop in this volume.) The first board devoted
to general veterinary practice specialties was formed in 1978 (AVMA,
1995). This is called the American Board of Veterinary Practitioners
and includes the specialties of avian, canine and feline, dairy, equine,
food animal, and swine health management practices.
In 1982, a new organization called the National Academies of Prac-
tice was established in Washington, DC. Patterned after the National
Academy of Sciences, the purpose of this organization is to recognize
various medical clinical specialties, and membership is based upon
election by one's peers as a Distinguished Practitioner in a specific
medical specialty. The National Academies of Practice specialties in-
clude Dentistry, Medicine, Nursing, Optometry, Osteopathic Medicine,
Podiatric Medicine, Psychology, Social Work, and Veterinary Medicine.
Veterinary Medicine became one of the nine Academies of Practice in
1984. The current Executive Director is a veterinarian, Dr. John .B
McCarthy, and there are presently 501 active and emeritus Distin-
guished Practitioners of the National Academy of Practice in Veter-
inary Medicine (McCarthy, 1995). For the past two years, a special
symposium on Veterinary Medicine and Human Health has been spon-
sored by the Academy and held in conjunction with the annual meet-
ing of the American Veterinary Medical Association. A second pro-
gram was sponsored by the Academy in 1995 in conjunction with the
silver anniversary symposium of the Student Chapters of the Ameri-
can Veterinary Medical Association (McCarthy, 1995).
4 .w JEAN SDDOD
II. Emergence of Veterinary Medical Specialization
A. NOITCUDORTNI
Since the early days of veterinary medical specialization, 19 recog-
nized colleges and specialty boards of the American Veterinary Medi-
cal Association have evolved with more than 4,400 certified diplomats
(AVMA, 1995). Over the years, veterinary specialists were primarily
employed by academia, industry, government agencies, and large vet-
erinary specialty practices or institutions. The present increasing
trend for the development of clinical specialty practices in the private
sector should be encouraged, as general practitioners benefit from
working closely with specialist colleagues in the community. As might
be expected, however, this emphasis on specialization has resulted in
"growing pains." The first of these arose from the need of specialists
and generalists to follow appropriate guidelines for their roles in the
practice of veterinary medicine, in order to minimize overlap and the
perceived or actual encroachment on their respective turfs. A second,
more difficult challenge related to the training and standards required
for entry into a specialty with the goal of subsequent board certifica-
tion in that specialty. Because most of the training programs are -fo
fered by veterinary medical teaching institutions, one could argue that
these standards may not necessarily reflect the needs in specialty clini-
cal practice. Thus, there has been a need to diversify training pro-
grams, specify the board certification process and professional certify-
ing examinations that reflect the state of the art in each specialty, and
ensure fair and legally defensible standards (Stromberg and Schnei-
der, 1994).
As pointed out in a recent review by Stromberg and Schneider
(1994), the law of due process requires that any standards upon which
an individual's economic opportunities may be affected must be "ratio-
nally related" to the stated purpose of the process of certification. This
means that the requirements for candidates to become certified must
accurately measure their competence in the specialty to which they
request certification. While it is clear that the appropriate written and
oral examinations may test a candidate's skill in the field and that
certain educational requirements are necessary to satisfy eligibility,
several of the specialty organizations also require that the candidate
prepare case reports, publish a minimum number of articles as first
author, or spend some time away from clinical practice performing
research. As stated by Stromberg and Schneider (1994), "These re-
quirements may not be supportable under the law, because they do not
WEIVREVO 5
necessarily measure or ensure practitioner clinical competence." The
objective of requiring case reports may be to demonstrate that candi-
dates have managed a variety of appropriate cases during their re-
sidency or other training, whether the cases have been managed prop-
erly, and whether the candidate can write an appropriate description
of the clinical laboratory and treatment records for the case. However,
the question remains about how many case reports a candidate would
be expected to prepare to be truly reflective of the variety of cases more
commonly seen in specialty practice. If the selected cases represent
rarely encountered clinical disorders, one could argue that this does
not reflect the ability of the candidate to deal with the more common
cases seen in a typical specialty practice. With respect to publishing
case reports, writing skills may be less important than oral communi-
cation in the practice of a clinical specialty. With respect to the certify-
ing examination, an argument can be made that merely being accepted
and successfully completing a clinical residency program should lead
the way to certification, for only about 10% of all licensed veterinar-
ians pursue specialty training and not all of these complete a formal
residency program or the specialty examination process (Stromberg
and Schneider, 1994). Finally, these investigators outline a series of
due process requirements that ensure procedural fairness (Stromberg
and Schneider, 1994):
• Are certification requirements clearly set out and conveyed to poten-
tial candidates?
• Are rules and requirements for certification followed equally in all
cases?
• Is the grading system unbiased?
• Is there a clearly stated, meaningful appeal process that is strictly
adhered to?
• Do rules governing retaking a portion or all of the examination re-
sult in equal treatment of candidates?
Answers to these questions have been offered by the authors who indi-
cate that they should "provide guidelines for modifying existing certi-
fication programs to make them more useful to the profession and the
public" (Stromberg and Schneider, 1994).
B. SCIENTIFIC SECNAVDA
.1 Basic and Clinical Immunology
During my 30-year career in biomedical research, the scientific ad-
vances made in the field of hematology and immunology have been
6 .w NAEJ SDDOD
remarkable (Dodds, 1988, 1992b). Interest in basic immunology has
increased over this period and has been further sparked by the discov-
ery of a group of retroviral agents affecting various mammalian spe-
cies and inducing profound immunological dysfunction and suppres-
sion as well as hematopoietic and other cancers. The discovery in the
1980s of human lenteviruses that produce adult T-cell leukemia and
acquired immune deficiency syndrome, with its devastating effects
throughout the world, has increased research efforts and funding for
this area of science and medicine (Marx, 1990). Early studies of the
immune system were focused on the phenomenon of the body's ability
to generate specific protective immunity following exposure to infec-
tious or toxic agents. This basic knowledge has progressed to an under-
standing of the cellular molecular components involved in the immune
system, definition of the B- and T-cell systems, and the role of genetic
determinants mediated through the major histocompatibility complex
(Marx, 1990). Today, the molecular basis of antigenic recognition by
T-cells and their pathways of activation, inactivation, and exhaustion
have been defined (Lanzavecchia, 1993). The importance of T-lympho-
cytes in immune functions is underscored by their central role in the
immune response. In this capacity, they kill infected cells, control in-
flammatory responses, and help B-lymphocytes to make antibodies.
The T-cell receptor on the cell surface recognizes antigens presented to
it as a complex of a short peptide bound to a molecule of the major
histocompatibility complex present on the surface of another cell. This
latter cell is called an antigen presenting cell. The major histocom-
patibility complex is made up of two molecules: class I determinants
which are expressed on all cells, and class II determinants which are
expressed on macrophages, dendritic cells, B-cells, and occasionally on
other cells. The major histocompatibility complex is highly poly-
morphic, and different allelic forms of the molecules have different
specific peptide binding characteristics (Lanzavecchia, 1993; Shoen-
feld, 1994).
The fact that antigenic peptides derived from intact proteins bind
directly to major histocompatibility class I or class II molecules present
on cell surfaces offers potential targets for immune intervention,
because it allows selected antigenic peptides to be added to T-cells
exogenously (Lanzavecchia, 1993). Knowledge of these basic immune
mechanisms has made it possible to identify strategies for immune
intervention in order to design protective vaccines; for example, to
induce effective responses to tumor antigens and even to control graft
rejection and autoimmune diseases (Lanzavecchia, 1993). These situa-
tions provide exciting possibilities for future research. I have a specific