Kansas State University -- Researching
and caring for animal cancer patients may help the search for cancer cures in
humans.
Dr. Ruthanne Chun, veterinary oncologist and assistant
professor of clinical sciences at Kansas State University, is searching for new
developments in the fight against cancers. She says the many similarities
between animals and humans with the disease can help in finding a cure.
"If animals are developing cancers from something
from the environment we can learn how to more effectively use animals as
sentinels, and what it might be in the environment that's causing the
cancer," Chun said. "Animals also get many similar tumor types as
people, and for some tumor types, animals get them more frequently and the
natural course of the tumor is much faster than it is in people.
"For instance, if a dog develops a bone tumor,
it's very similar to the development of bone tumors in humans," she said.
"But humans, maybe 2,000 new cases are diagnosed per year, whereas in dogs
maybe 10,000 new cases are diagnosed per year, so we can get a lot of
information about that particular tumor and how it responds to therapy in dogs,
and then move that therapy information over into humans."
Chun's current research focuses on clinical trials and
looking at new chemotherapy drugs, or drugs that have been used in people for a
long time, but researchers don't know what the effects are on dogs and cats.
"My main goal is recruiting cases, making sure
that regional veterinarians know that I'm here and that I would love to help
them out with their cancer cases," Chun said. "I would also like to do
some basic research and my main area of interest is with new blood vessel
ingrowth into tumors.
"For a tumor to grow it needs to have nutrients,
and for nutrients to get there, the tumor has to induce new blood vessels to
grow," she said. "It's a huge area of research in human medicine and a
lot of other veterinarian oncologists are looking at many different aspects of
it."
The tumors Chun is interested in treating are bone
tumors in dogs, vaccine-associated sarcomas in cats and mast cell tumors, which
are a common skin tumor in dogs.
"I guess with my cancer research in particular,
what is really exciting about it is that if we can stop the ingrowth of new
blood vessels, we might not have to use chemotherapy," Chun said. "So
it's possible that the drugs that we might use to stop blood vessels from
growing would be much less toxic than chemotherapy and maybe much more helpful
than chemotherapy.
"And if we can use that effectively in dogs and
cats, it's possible that they can use that effectively in humans, so that's my
longest term goal," she said. "I think realistically, I'm not sure
that we're ever going to ever really be able to stop cancer, or at least not in
my generation, but the more we understand it, the more we can control it."
University of Illinois, Urbana-Champaign --
Putting a pacemaker in a dog may sound high-tech and far-fetched, but the
practice is neither as uncommon nor as costly as you might think. As pacemakers
for human beings have become fairly routine, lower prices and increased
availability have made them an option that can extend some animal's lives for
several years.
"Between 100 and 200 pacemakers are implanted into
animals--mostly dogs but some cats and horses--in the United States each
year," notes Dr. David Sisson, a veterinary cardiologist at the University
of Illinois College of Veterinary Medicine Teaching Hospital in Urbana, where
the procedure is done 6 to 20 times a year.
Dr. Sisson knows what he's talking about. For the past
5 years, he has served as the director of a pacemaker registry started in the
late 1980s by the Cardiology Specialty of the American College of Veterinary
Internal Medicine, an organization of veterinary medical specialists who have
completed special training and passed a certifying exam. There are about 70
veterinary cardiologists in the United States.
"Pacemakers can correct the same abnormalities in
dogs that they do in people," he explains. Normally the body sends an
electrical charge to stimulate the chambers of the heart to contract and pump
blood through the body. In a condition known as sinus node dysfunction, or sick
sinus syndrome, an abnormality of this electrical charge causes a very slow
heart rate (bradycardia).
Heart block is another condition that may be treated
with a pacemaker. It occurs when the top chambers of the heart, the atria,
receive the electrical charge but the impulse doesn't make it to the lower half
of the heart, or ventricles, because of a blockage.
"The main symptom of these disorders is a slow
heart rate that cannot be accounted for by other reasons, such as hypothyroidism
or other underlying metabolic problems," says Dr. Sisson. "Some dogs
with a slow heart rate will also exhibit fainting episodes that last 10 to 15
seconds and may occur as often as ten times a day."
Dogs who need pacemakers--like their human
counterparts--are typically older. The average age is 9 years. "The best
candidates have hearts in reasonably good shape and have no systemic illnesses,
such as cancer, that would unnecessarily shorten their life span," says Dr.
Sisson.
"A pacemaker is made up of a pulse generator and
wires," he explains. "The pulse generator, which is about the size of
a silver dollar but thicker, contains an energy supply and a tiny computer that
monitors and controls the rhythm of the heart. Wires called leads transmit
electrical impulses between the pulse generator and the heart. When the
pacemaker detects that the heart's electrical activity has failed, it sends an
appropriate stimulus to get the heart going at the correct rate."
Twenty years ago, pacemakers were always implanted
surgically. Surgeons cut through the chest wall to attach the leads to the
heart. The leads were brought through the rib spaces and connected to the pulse
generator, which was implanted on the animal's flank. This is still the standard
procedure used with cats.
A less invasive approach was developed in the early
1980s. In this procedure, a lead is threaded through a vein in the neck until it
reaches the heart. A tiny retractable screw built into the lead attaches it
firmly to the heart muscle and keeps it in place until scarring anchors it
there. The pulse generator is inserted under the skin at the back of the dog's
neck. This technique--which may require only one day in the hospital--is less
risky for older dogs who may not withstand major surgery.
The prognosis for dogs with pacemakers depends largely
on how healthy the dog is other than having an abnormal heart rhythm. A
pacemaker often extends the life of the dog 3 to 5 years. Young dogs that
receive pacemakers because of congenital heart blockage typically do very well.
For owners, this treatment is not too taxing. "The
dog is essentially cured and there are no pills or injections to
administer," Dr. Sisson points out. "All owners have to do is bring
the dog in for a checkup once or twice a year to make sure the pacemaker is
functioning correctly. The cost of the procedure is about the same as the cost
of bone plating--surgical repair of a fractured leg in a dog."
The pacemakers used for dogs are the ones made for
people. Manufacturers often donate unused pacemakers when several months have
expired from the shelf-life of the power source, making it undesirable for use
in human beings. Receiving a pacemaker powered for 5 instead of 7 years in not a
problem for dogs, since they have much shorter life spans than people do.
Sometimes dogs receive a secondhand pacemaker from a deceased person.
As director of the pacemaker registry, Dr. Sisson
contacts manufacturers to request donations of pacemakers, matches donated
pacemakers with needs nationwide, and collects data from board-certified
veterinary cardiologists about the conditions and outcomes of all pacemaker
surgeries. He's currently working on article that will report on 5 years of data
from the registry.
Dr. Sisson advises owners considering this procedure in
their dog to seek a board-certified surgeon or cardiologist who is trained to do
appropriate programming of the pulse generator. These specialists can make sure
the computer is sensing and pacing the heart correctly.
University of Illinois, Urbana-Champaign --
Medical research carried out at the University of Illinois College of Veterinary
Medicine at Urbana may one day benefit you as well as your pet. Dr. Nicole
Ehrhart, veterinarian and surgical oncology specialist at the Veterinary
Medicine Teaching Hospital, is studying bone growth and repair in dogs receiving
chemotherapy. Her research is finding new alternatives to amputation and
intravenous (IV) chemotherapy and improving the accuracy of prognosis following
the treatment of bone cancer.
When dogs get bone cancer in a limb, the traditional
treatment is amputation and chemotherapy. Alternatively, the limb can be saved
with a "limb-sparing" technique by transplanting donor bone from a
cadaver. A new form of limb-sparing, known as bone transport, grows new bone in
the gap left after bone tumor removal.
With the bone transport technique, a cross-sectional
piece of the remaining normal bone is cut and moved a short distance from the
area it was removed from. The body recognizes this as a fracture and begins to
heal it. A device called an Ilizarov, named after the Russian scientist who
developed it, holds the cut piece of normal bone in place and allows it to be
moved a short distance each day. As the cut piece is moved further and further
away from its original site, new bone grows behind it.
The advantage of bone transport over the use of a donor
bone is that the patient's own bone is growing. Cadaver bone is both expensive
and susceptible to infection. Until the body establishes a blood supply to it,
the new bone is a high-risk environment for bacterial infection. About 35
percent of these patients get infections. Bone transport patients always have a
blood supply to the growing bone, which allows the immune system to take care of
any infection.
"This method has been used successfully in people
with bone loss from trauma, such as motorcycle accidents. It has never been done
with chemotherapy. Bone cancer has to be treated with chemotherapy. Nobody knows
the effect of chemotherapy on bone that grows as you transport the bone,"
says Dr. Ehrhart. "We are researching this limb-sparing option for dogs,
but it may also benefit humans. Bone cancer affects children more often than
adults, and children are still growing. This technique would allow new bone in
kids to grow out to equal length as the opposite limb."
If it turns out that chemotherapy hinders new bone
growth, Dr Ehrhart's research should be able to find out why. By comparing
groups of control dogs and chemotherapy dogs, she hopes to isolate proteins
responsible for bone growth. The next phase will be to give these proteins to
the chemotherapy group to see if it stimulates bone growth.
"We are also studying an alternative to IV
chemotherapy," says Dr. Ehrhart. "We are one of only two institutions
with USDA permission for clinical use of a biodegradable polymer sponge that
dissolves over time when implanted in the body, providing a slow-release
chemotherapy." In preliminary trials this method has been shown to work as
well as IV chemotherapy. The slow-release chemotherapy has the potential to
control local recurrence of the tumor as well as metastatic disease (spread of
the tumor). This method of chemotherapy is less toxic than IV chemotherapy and
requires fewer doses. Clinical studies will begin here this fall on dogs with
cancer.
"Another study we are doing will enable us to make
more accurate prognoses for animals with bone cancer," Dr. Ehrhart says.
"There is evidence that the amount of bone-specific alkaline phosphatase in
the blood before and after cancer surgery is a good indicator of post-surgical
survival time." Patients with higher than normal levels of this enzyme in
their blood before they have surgery have a poorer prognosis than patients with
lower levels. Also, if the amount of this enzyme in the blood does not return to
normal after surgery, then the patient has a lower chance of survival and a
lower remission-free interval than normal. This finding is independent of the
stage, the location, and the amount of cancer present and of metastatic disease,
but it is correlated with survival time. This information will provide a more
accurate prognosis than before. Patients with higher bone-specific alkaline
phosphatase levels can be treated more aggressively with chemotherapy after
surgery in order to achieve the same survival rates as patients with lower
levels.
"Animal research and human research are very
intertwined," says Dr. Ehrhart. "Usually disease is induced in animals
to provide research models for human medicine. Our research is with naturally
occurring bone tumor patients. We work to improve the animal's quality of life,
and the information we get is helping to improve the quality of life of people
with bone cancer, too."
Kansas State University -- Cancer is an often
life-threatening disease that many people think affects only humans. So it comes
as a shock to many pet owners when their pet is diagnosed with cancer.
Dr. Ruthanne Chun, assistant professor of clinical
sciences at Kansas State University's College of Veterinary Medicine, says
cancer in animals is not uncommon and it is very similar to cancer in humans.
"It can either be genetic, environmental or just a
random mutation, so it's very similar to cancer in people," Chun said.
"The common types of cancer that we see may be more common because we can
detect them more easily.
"They involve the lymph nodes, limbs or skin
tumors, so they are visible and easy to see," she said. "There are
some tumors in dogs like lung tumors that we might not pick up at all until
they're very large and causing the dog to have clinical problems, so it really
depends on the type of cancer."
Chun says there are a number of indicators that an
animal may have cancer. The best way to detect cancer, she advises, is for
owners to feel their animals over carefully once a week.
"Just pet them thoroughly once a week and feel for
abnormal lumps, bumps, swellings and any area that's painful," Chun said.
"Sometimes animals will have open wounds that are ulcerated that don't heal
for a long time, and that would be another potential sign that it's
cancer."
There are also very non-specific things like not eating
well, weight loss, vomiting or diarrhea, she said. Also, certain breeds are more
prone to getting cancer than others.
"Breeds such as boxers, Bernese mountain dogs and
golden retrievers are overrepresented in the development of cancer," Chun
said. "There have even been studies that have traced the family tree of
dogs, and these have suggested a genetic predisposition."
Often the diagnosis of cancer leaves owners feeling
that there is no hope for their pet. However, Chun says that many times the
cancer can be treated, and the pet can continue to lead a fulfilling life.
"When we treat animals with cancer, we carefully
measure how good is the animal's quality of life versus how aggressive should we
be with our therapy," Chun said. "We use the same types of drugs that
they use in human medicine, but because we really want to maintain a good to
excellent quality of life in our patients we tend to use lower doses at less
frequent intervals."
Veterinarians have designed their chemotherapy
protocols for animals so that pets don't become terribly ill, Chun said. Less
than 5 percent of the animals develop severe vomiting, diarrhea or a drop in
their blood counts and need to be hospitalized.
"Most of my patients and the owners don't even
realize that the animal has had chemotherapy," she said. "Owners
always worry about the animal's hair falling out.
"Bald dogs do look pretty different, but it's
actually not very common for their hair to fall out," Chun said.
"Animals that always have to go to the groomers, those are the ones we
worry about losing their hair. But once chemotherapy is over, the animal's hair
grows back in."
Cost is a significant factor in deciding to go through
with the cancer treatments. For many people, their pets are more than just
animals, so the owners want to do everything that they can to prolong their
lives and keep them feeling good.
"I know a lot of people say, 'Well $2,000, I don't
have that kind of money, I can't afford it,' and I understand and wish we could
make things cheaper, but for other people they feel very strongly that it is
worth it and they can set aside the funds," Chun said. "If we look at
it solely from the animal's point of view, and are able to buy them another
eight to 12 months to maybe even a year and a half, that's a very long time from
that animal's point of view. So usually from their perspective I think it's
worth it."
University of Illinois, Urbana-Champaign --
"A number of animals who come in for emergency care at veterinary clinics
wouldn't survive surgery or trauma unless blood was made available for
them," says Kristi Stasi, veterinary technician at the University of
Illinois College of Veterinary Medicine Teaching Hospital. "The process of
collecting and transfusing blood is very similar in veterinary and human
medicine."
Blood is species specific-dogs can receive only dog
blood and cats can receive only cat blood. In addition, dogs and cats have blood
types just as humans have blood types. Cats have A, B, and AB groups with
specific factors within these groups that further differentiate them. Dogs have
eleven different blood groups; the most important one is the A1/A2 system. Dogs
that are A negative are considered universal donors. Cats do not have a
universal donor; therefore, it is especially important that donor and recipient
are cross-matched.
Multiple transfusions can also be a problem. Even
though the donor and recipient may be compatible originally, the recipient's
immune system may build up a sensitivity to a specific donor. "Thus, every
time you transfuse, you need to cross-match to make sure that your donor and
recipient are compatible," explains Stasi.
There are two types of cross-matching tests: major and
minor cross-matching. "For major cross-matches, red cells from the donor
are mixed with serum from the recipient. We observe to see if there is a
reaction; the recipient may attack donor cells and not accept them. If you have
a major cross-match incompatibility, unless you are desperate, you shouldn't do
a transfusion," explains Stasi. In a minor cross-match, the recipient's red
cells are compared with the donor's serum. Usually, in minor incompatibilities,
parts of the donor's blood can be given to the recipient but not the blood in
its entirety.
The different blood components-red cells, plasma, and
platelets-can be separated if need be. "Red cells are given to a patient
that may be anemic due to trauma or due to a treatable disease. Plasma is used
to build up blood volume in situations when the animal is not making enough or
is losing too much protein. Platelet-rich plasma is for those patients whose
platelets are depleted or dysfunctional," says Stasi.
As with human blood donors, animal donors are tested to
make sure blood values are high enough and no infectious disease is present
before blood is drawn. Donors must meet weight requirements-10 pounds for cats
and 50 pounds for dogs. Fluid is replaced after blood is drawn, and the body
compensates by producing new red blood cells. Also similar to human donors,
there must be a waiting period of at least two months before blood is collected
again.
Private veterinarians sometimes use their pet dogs or
cats as blood donors when emergencies arise. The University of Illinois
Veterinary Medicine Teaching Hospital relies on one of a small number of canine
blood banks in the United States to meet the needs of most of its patients.
Kansas State University -- Acupuncture is a
treatment that has been used by the Chinese for centuries. More recently,
western cultures have begun utilizing it for the treatment of humans and
animals. Judy Cox, veterinarian and associate professor of clinical sciences at
Kansas State University, is a trained acupuncturist who treats animals with this
unconventional method of treatment.
"Some of the most common treatments are for relief
of pain and chronic conditions like arthritis, where perhaps for one reason or
another medications aren't the best choice," Cox said. "It works well
for almost anything except tumors -- things that respond best to surgery -- and
some things where we know we have medications that work very well."
Acupuncture can be applied to most animals, including
horses, cows, dogs, cats and even birds, with costs ranging from $25 to $80 per
session, depending on the size of the animal. The needles are very small, so
discomfort is far less than receiving a vaccination.
"Many animals become very relaxed during an
acupuncture treatment," Cox said. "Some of them almost go to sleep.
"Acupuncture causes the release of certain
neurotransmitters in the brain, and so some of those neurotransmitters cause
feelings of relaxation and happiness," she said. "Of course we can't
ask the animal how they feel, so we can't be sure it's exactly like people, but
at least it causes the same physiologic changes in the animals that it does in
people."
According to Cox, the concept of acupuncture being
applied to animals is not a new one. She says thousands of years ago, the
Chinese performed acupuncture on war horses and other animals of value.
"From the western science theory, most of the
acupuncture points are located over small neurovascular bundles where there are
tiny nerves, blood vessels and collections of cells which are manipulated by the
needle insertion," said Cox. "The Chinese believed that there are
energy flows below the skin and they follow certain patterns called meridians.
"The acupuncture points are along those meridians," she said.
"And the Chinese theory is that illness is an imbalance of the body and
wellness is a balance of the body, so you select points to put your needles that
well help the body return to balance."
Despite many positive results of acupuncture, the
biggest criticism is that it has not been as well studied with western
scientific methods as conventional western medicine.
"The Chinese did not do the kind of research
trials that we do, and in fact we've only done that for the last 40 or 50 years,
and this is a very ancient art," Cox said. "So the critics would say
that we don't have any proof that it works, and that much of what happens could
just be coincidence.
"Now that we're using acupuncture more in the
United States, where we tend to study these things very scientifically, I hope
we will keep track of cases and do the appropriate studies, so that in 10 or 15
years we'll have the scientific evidence that everybody's looking for," she
said.
University of Illinois, Urbana-Champaign --
Carbon dioxide (CO2) laser surgery has been used in human medicine for many
years in detailed work such as cosmetic surgery. Veterinarians like Dr. Karen
Campbell, of the University of Illinois College of Veterinary Medicine Teaching
Hospital, are finding other surgical uses for this high-energy source that
vaporizes water molecules.
"Living cells are 70 percent to 80 percent water.
The laser evaporates the cells at the same time it evaporates the water,"
explains Dr. Campbell. "The greatest benefit of the laser is that you can
vaporize tumors that are difficult to treat with conventional surgery."
For example, Dr. Campbell recently used the CO2 laser
to do surgery on a 15-year-old dog with large benign tumors on its ears.
"One of the tumors was quite extensive and was becoming infected," she
says. "The uncomfortable dog shook its head a lot." Instead of
traditional surgery that would remove part of the ear, Dr. Campbell and the
owner opted for CO2 laser surgery, which removed the tumor and left the ear
intact.
Laser surgery has many benefits. With the CO2 laser
most superficial surgeries require only local anesthesia. Stitches usually are
not necessary for incisions made with the laser because the incision site heals
very quickly. There is less worry about pets chewing or licking the surgery site
afterwards. With no stitches and quick healing, the surgery site often heals
without scarring, which is one reason the CO2 laser is popular for human
cosmetic surgery.
Because the laser cauterizes (seals off) blood vessels,
it is useful in areas such as the mouth, which is especially prone to bleeding
during surgery. Less blood means better visibility and faster surgery time. The
laser also sterilizes as it cuts, minimizing postoperative infection.
"One new application of the laser is in treating
transitional cell tumors of the bladder. With the bladder, it is important that
you preserve as much tissue as you can while removing the tumor," says Dr.
Campbell. With CO2 lasers you can see all the area being cut and you do not
destroy tissue below.
The laser vaporizes cells only 0.1 millimeters below
the surface. For large tumors, scalpel surgery might be used in combination with
the CO2 laser. "We can scalpel the tumor off and use the laser to touch up
the bed of the lesion. If there are residual dead cells, the body eliminates
them and hopefully has an immune response that will protect it against like
tumors developing," adds Dr. Campbell.
The laser is not most advantageous in every procedure.
Besides the minute depth at which the laser cuts, cost is also a factor.
"The unit we have retails for about $30,000. So many veterinary clinics
will not have enough business for laser surgery to be able to afford this
equipment. Routine surgery with an experienced clinician is often the best
choice," says Dr. Campbell.
Advances in human and veterinary medicine fuel each
other. Dr. Campbell views laser technology as an opportunity to help owners give
quality care to their pets in many circumstances. For further information about
technologies available in veterinary medicine, talk with your local
veterinarian.
University of Illinois, Urbana-Champaign -- At
the Cancer Care Clinic at the University of Illinois College of Veterinary
Medicine in Urbana, advances in human cancer medicine are benefiting pets, and
studies with animal cancer patients yield findings that help human patients.
Dr. Barbara Kitchell, the veterinarian who heads the
clinic, is board certified in both oncology and internal medicine and has
studied with cancer researchers at Stanford University. Her ties to human
medicine benefit her canine patients. For example, for certain cancers she
prescribes gencytabine, a new chemotherapy drug used commonly in human medicine
which has gentle side effects. "We are the first veterinary college to use
this drug in the treatment of animals, although it is commonly used in human
patients for hard-to-treat cancers of the lung and colon," says Dr.
Kitchell.
Dr. Nicole Ehrhart, a surgical oncologist, specializes
in procedures such as limb sparing, radical head and neck surgery, and
hemipelvectomy. Dr. Ehrhart's limb-sparing techniques have made her
world-renown. Certain cancerous limbs can be saved by transplanting donor bone
from a cadaver. A new form of limb sparing, known as bone transport, grows new
bone in the gap left after bone tumor removal. With the bone transport
technique, a cross-sectional piece of the remaining normal bone is cut and moved
a short distance from the area it was removed from. The body recognizes this as
a fracture and begins to heal it, regrowing healthy bone that replaces what was
cut out. She is studying how this technique could be beneficial for children
with cancer of their long bones.
Diagnostic equipment developed for use in human
medicine is another vital tool in veterinary oncology. The College of Veterinary
Medicine has magnetic resonance imaging (MRI) and computed tomography (CT)
capabilities to help pinpoint the tumors that need to be removed or treated with
radiation and chemotherapy.
A cutting-edge treatment modality borrowed from human
medicine, hyperthermia, is used in combination with radiation at the Cancer Care
Clinic to increase the cancer-killing function of the body. "Hyperthermia
creates heat in the tumor about the same temperature as a fever," explains
Dr. Kitchell. "This unit has the capability of conforming to the shape of
the tumor. Even the depth of the feverish tissue is controllable. This combined
therapy reduces the size of the cancerous tissue so surgeons can more easily
remove the cancerous area."
Often, the oncologists at the College are allowed
access to treatments not yet available in human medicine. Because animals share
humans' environment, drugs' effectiveness in pets is often an accurate indicator
of how the drug will perform in humans. The oncologists use only drugs that have
been well tested. Trying the newest treatments may help cure your pet and at the
same time provide valuable information on how effective the drugs may be in
human therapy.
"First and foremost is our commitment to improving
the quality of life and survival duration of companion animals who develop
cancer," says Dr. Kitchell. "The Cancer Care Clinic also seeks to
identify strategies of therapy, prognostic factors, or diagnostic tools that can
be evaluated in animals with spontaneous malignancies. We hope that ultimately
our studies will help transfer technology to human cancer medicine. Companion
animals with cancer provide an extremely important resource for the development
of anti-cancer strategies that bridge the gap between human cancer patients and
findings in cell cultures and rodent models."
Kansas State University -- For some people, a
string of beads is a fashion statement. For your dog or cat, they may be the
difference between life or death.
When surgery can't be performed or isn't enough to
remove cancerous tumors, veterinarians at Kansas State University's College of
Veterinary Medicine are using a new, implantable radiation treatment option.
According to Dr. Ruthanne Chun, assistant professor of clinical sciences at
K-State, brachytherapy is for dogs or cats that have certain tumors that aren't
likely to spread to other parts of their body
"Brachytherapy is something we've tried do more
and more of here," Chun said. "There are maybe two or three other
veterinary colleges that do it, so we are really riding the edge of that wave in
being able to offer this service."
After as much of the tumor as possible is removed, a
hollow, sterile plastic tube called an "after-loading tube" is sutured
into the tumor bed. After the wound is closed, Chun said the radioactive beads
are "essentially strung together on a plastic wire" and
"fed" into the after-loading tubes. Once clamped in place, they begin
to emit a set amount of radiation into the tumor bed.
"We know from past experience how much of a dose,
how much radiation, a tumor needs to be effectively treated," Chun said.
"We can calculate roughly how much radiation per day the tumor bed is
receiving. After it has gotten its set dose, we sedate the animals, remove the
tubes and the beads and they're done with their therapy."
Because the beads provide a continuous, low level dose
of radiation, animals must be kept in isolation. Chun said owners are not
allowed to visit their pets while they are receiving brachytherapy. The pets may
still be allowed to go outside but must be kept away from other animals. They
must also be handled only by veterinarians licensed to work with radioactive
substances.
Chun said the treatment is, in some ways "much
nicer" than conventional forms of radiation therapy. Animals do not have to
go under anesthesia multiple times and the duration of the therapy is much
shorter than with conventional or external beam radiation therapy.
"For conventional radiation therapy where you use
an external beam unit, the animal has to lie still for the radiation therapy;
this requires daily anesthesia anywhere from 10 to 15, or 20 times -- depending
on what type of tumor it is," Chun said. "And the costs really add up
when you have to anesthetize the animal each time and allow time for recovery.
It's much harder on the animal than doing the implant therapy."
Chun said not all tumors can receive the implant, but
that it is a good treatment option for a lot of different tumors.
"It seems to be as successful as more conventional
forms of therapy," Chun said. "But we need two or three years from now
before we can say our dogs have survived as long as, if not longer than, dogs
treated with other forms of radiation."
Kansas State University -- It is estimated that
one in five of the 44 million adult dogs in the United States suffer from
arthritis to some degree, said James Roush, doctor of veterinary medicine at
Kansas State University.
There are some signs pet owners can look for to tell
when dogs are experiencing pain from arthritis.
"First, you will see some sort of lameness or
reluctance to get up or move around," Roush said. "Owners will often
note that the dog doesn't jump on or off the bed as often. The other things you
can see are swelling in the joints, and heat or pain when you touch the joints.
The dogs also won't like their legs moved."
There are two common reasons dogs develop arthritis.
The most common reason is dogs may have skeletal or joint diseases that are
congenital, which means the diseased joints form because the dogs inherit
imperfect physical traits, Roush said.
Hip and elbow dysplasia, degenerative joint diseases,
are examples of common congenital diseases in large-breed dogs. Large dogs have
big skeletal frames and grow faster than normal, which can cause stress on the
joints, leading to arthritis.
The second most common cause of arthritis in dogs is
damage to joints from accidents. Damage to ligaments in knees and shoulders are
common joint injuries received from accidents. In time, this can lead to
inflamed joints and arthritic symptoms.
There are some treatments available to ease the pain of
arthritis. Roush said the treatments have commonly been the same drugs used for
arthritis pain in humans, such as aspirin or other anti-inflammatory drugs.
"With dogs, the mainstay has always been aspirin,
buffered aspirin or a trademark called Ascriptin," Roush said. "These
have to be given three times a day and they cause some stomach ulceration or
gastrointestinal bleeding in a fair percentage of dogs."
Roush said it is important to remember that, while
aspirin and buffered aspirin are often used to treat human arthritis pain, there
are analgesics used for humans that should never be used to treat dogs'
arthritic symptoms.
"Other arthritis drugs used in people, for
instance Ibuprofen, can have serious side effects in dogs," Roush said.
"Ibuprofen has less side effects for humans, but one full tablet of
Ibuprofen can actually kill a dog."
A new drug for arthritis pain in dogs, carprofen or
brand name Rimadyl, is an anti-inflammatory that was just approved for use in
the United States in early 1997. This drug may be a more effective treatment for
arthritis pain in dogs.
"The benefit of the new treatment is that it
simply causes less side effects in dogs than aspirin, and it's still as
effective, or maybe more effective because we can give it in slightly higher
doses," Roush said. "The other advantage is it only needs to be given
twice a day. It's a little easier for owners to give it in the morning and at
night and not have to give it in the middle of the day."
The average cost of the drug is about 44 cents per
tablet. Roush said that, as an example, it would cost from $20 to $30 a month
for an 80-pound Labrador retriever to take the carprofen pills. Roush said
prices will vary according to the dosage level needed by the dog, which is
judged by the weight of the dog.
Roush said that neither carprofen nor aspirin stops the
advancement of arthritis. He said analgesics such as these only make the dog
more comfortable. In addition to the analgesics, there are some other options
that can help dogs with arthritis.
"If dogs have mild arthritis, just like you or I,
if we give them an aspirin, they feel a lot better," Roush said. "If
they really have a severe crippling disease, other options should be considered.
For instance, with hip dysplasia, a total hip replacement will relieve the pain
of the dog. For other joints, we can actually fuse those joints, taking away the
motion, and eliminate the pain."
Kansas State University -- In racing greyhounds,
it's called Alabama Rot; in people, E. coli food poisoning or hemolytic uremic
syndrome. Both can cause acute renal failure, sometimes death, and both are
believed caused by the E. coli bacteria.
Brad Fenwick and Laine Cowan, veterinarians at Kansas
State University's College of Veterinary Medicine, believe the similarity of the
diseases between greyhounds and humans will provide a major step in researching
the diseases caused by the deadly bacteria Escherichia coli, commonly known as
E. coli. The bacteria is common to the environment and can be found in
undercooked or raw ground meat.
"The disease in greyhounds appears to be the best
model of the human disease. Using dogs as a model, we will be able to gain a
better understanding of the underlying disease process, innovative approaches to
treatment, and hopefully ways to prevent hemolytic uremic syndrome. It will
allow us to conduct studies that simply have not been possible previously,"
said Fenwick, associate professor of veterinary pathology.
The greyhound disease was first recognized at a
greyhound race track in Alabama, although now it occurs nationwide. Racing
greyhounds are fed raw ground meat which makes them prime candidates for E. coli
exposure. E. Coli food poisoning in humans also is caused by eating poorly
cooked meat. The hemolytic uremic syndrome is a life-threatening disease and the
most common cause of acute kidney failure in infants and children. Adults,
adolescents and newborns also can be infected.
In research on "Alabama Rot" in greyhounds,
Cowan found a striking similarity between the changes in the kidneys of infected
greyhounds and humans with hemolytic uremic syndrome.
"In dogs, because the blood supply to the skin
also is affected, the disease usually starts with ulcers on the skin. Like in
humans, some of the dogs also have kidney failure due to blockage of the blood
supply to part of the kidney," said Cowan, assistant professor of small
animal medicine. "Humans don't get the skin form, but when the disease
advances to the kidney failure stage in both humans and dogs it is almost
identical."
The problem with E. coli infection is that there is no
cure, Fenwick said. "The toxins produced by the bacteria attack the cell
lining of the blood vessels. When people and dogs are infected there is no
specific therapy. Only the symptoms such as diarrhea and dehydration can be
treated. That's why the discovery of an animal model is so important."
Cowan and Fenwick began researching the greyhounds in 1993. Sick greyhounds from
around the country were referred to the K-State veterinary clinic for care. Only
recently have K-State researchers discovered what was causing the disease in the
dogs.
"We found that antibiotics and anti-inflammatory
drugs have no recognizable effect," Fenwick said. "But the good news
is, like in humans, the dogs respond to supportive care."
Supportive care can involve intravenous fluids,
transfusions and dialysis, the same treatment provided to children with
hemolytic uremic syndrome.
Tufts University -- When your horse gets sick
and needs antibiotics, the veterinarian generally prescribes systemic
antibiotics that circulate through the entire body. The problem with that kind
of therapy is that it doesn't necessarily send the medication to the point of
the infection or injury in the desired concentration. And because of a horse's
size, it's extremely expensive to achieve that desired concentration.
So researchers have come up with targeted antibiotics,
a therapy used in human medicine for more than a decade but only recently in
equine medicine.
"The idea behind it," said Dr. Carl Kirker-Head,
associate professor of surgery at Tufts University School of Veterinary
Medicine, "is instead of introducing antibiotics orally or intramuscularly
in large quantities, which has potential drawbacks in terms of cost and
allergies, is to introduce large quantities of antibiotics at the scene of the
crime -- at the injury site or at the infection site. "Historically, if a
horse stepped on a nail, for example, and contracted an infection of the coffin
bone, the equine surgeon would go in and clean up the wound, put the foot in a
cast and put the horse on systemic antibiotics.
"Now we can take our antibiotic, mix it with a
carrying agent and implant it during the surgery," said Kirker-Head,
section head of large animal medicine and surgery at Tufts' Hospital for Large
Animals. "That mechanism releases large quantities of antibiotics slowly
over a period of days and weeks right where we want it."
Kirker-Head mixes the antibiotic in a bone cement
called polymethylmethacrylate. The only disadvantage is that the cement
generally has to be removed, so researchers are trying to identify a suitable,
absorbable carrier that will dissolve over time, negating the need to do the
second surgery to remove the cement.
"This system reduces the cost of antibiotic
therapy massively, especially when you consider a large horse," said Kirker-Head.
Kirker-Head and his orthopedic surgical team also are
pioneering the use of so-called "standing surgeries," which result in
a much quicker recovery and lead to a reduced risk of infection.
"In the traditional surgery, you still have to
administer general anesthesia, but we are perfecting the use of the procedure in
the standing animal with a local anesthesia," Kirker-Head said.
"This is being attempted at only a few
institutions." The advantages are clear: Reduced risks associated with
general anesthesia and substantially reduced costs. And the procedure is done on
an out-patient basis. "We are not only using standing surgeries with
arthroscopy but also in other orthopedic surgeries," Kirker-Head said,
including osteostixis, in which shin bone fractures are repaired by drilling
small holes through the bone to the marrow to improve blood supply to the
fracture site. We have been doing this for a few years now, but again, only a
few large veterinary hospitals are doing it on the standing horse under a local
anesthetic.
"I did the bone-drilling technique on my own
horse, Knightly Thunder, who is a Stakes winner," said Kirker-Head, who
owns the horse with his wife. "We bred and raised her. She won her first
race. Then she developed some problems with her leg, so we treated her here, and
she went on to win again."
Equine sports medicine, which integrates clinical care
and research on the special problems of performance horses, is one of the
signature programs of Tufts' veterinary school.
Tufts University -- A study done at Tufts
University School of Veterinary Medicine has led to the nation's first blood
substitute that could dramatically reduce the demand for fresh blood in
emergency situations and save tens of thousands of critically injured animals.
Earlier this year, the U.S. Food and Drug
Administration gave regulatory approval to Biopure Corp., a biotechnology
company based in Cambridge, Mass., and the study's sponsor, to market Oxyglobin,
the nation's first oxygen therapeutic blood substitute for the treatment of
canine anemia. (Clinical trials are ongoing for another Biopure blood substitute
that could be used in human medicine.)
"This is very exciting," said Dr. Robert
Murtaugh, professor of medicine at Tufts School of Veterinary Medicine and
principal investigator for the eight-month clinical trial at Tufts. "Oxyglobin
is the first alternative to donated blood, so this is really a revolutionary
development. The product quickly delivers oxygen into tissue and organs and buys
time for the dog's own regenerative red blood cells to come back."
Oxyglobin is created by using purified hemoglobin
molecules derived from cow's blood. Hemoglobin in red blood cells delivers
oxygen throughout the body, but anemia results if the number of red cells is
reduced, as often happens during trauma, starving bodily tissues of oxygen. This
potentially life-threatening condition often goes untreated in dogs.
"Anemia is a common condition in dogs that often
is not treated because donated blood is either not available or is too
labor-intensive to administer," Murtaugh said. "Because Oxyglobin is
easily accessible, it will give every veterinarian the ability to treat anemic
dogs quickly, effectively and safely."
Oxygen therapeutics offer key advantages over donated
human or canine blood. They do not require blood-typing or cross-matching for
use; they can be stored at room temperature for up to two years; they can be
produced in ample supply; they are derived from controlled donor sources, and
the production process eliminates potential bacterial, viral and other
infectious agents.
Biopure estimates that the worldwide veterinary market
for Oxyglobin will grow to $100 million. The company also has similar blood
substitute products for humans that are in advanced clinical trials in the
United States and Europe.
Researchers in government and the private sector have
been working to develop a blood substitute for use in humans for more than 50
years. Efforts intensified in the early 1980s with the advent of AIDS and the
risk of transmitting HIV and other infectious diseases, such as hepatitis, via
donated blood.
"When the history of 20th-century medicine is
written, the development of oxygen therapeutics will be listed among the top 10
advances," said Dr. C. Everett Koop, former U.S. Surgeon General and a
Biopure director.
It
may surprise some people, but when horses get hoarse or man's best friend's
health goes to the dogs, the animals take many of the same medicines as their
owners do. People and animals share a number of the same diseases, ranging from
asthma and epilepsy to high blood pressure and cancer. Therefore, they benefit
from many of the same treatments as humans. For example, a number of medical
treatments and vaccines used to treat animals were originally developed for
humans through animal research. In addition, veterinarians now use medical
imaging devices commonly used for humans and originally tested on animals to
treat pets, livestock and wildlife. Experts say this is precisely what makes
learning about animal health so important. The knowledge gained helps humans and
animals live healthier lives.
