CAHF research grants, 2011-2012

canine treadmill

Chyna, a patient at the WCVM Veterinary Medical Centre. A WCVM team will study the effects of treadmill exercise on healthy dogs. Photo: Christina Weese.

In March, members of the Companion Animal Health Fund’s advisory board approved the allocation of more than $75,000 to eight pet health research projects at the Western College of Veterinary Medicine.

The funding will fuel the work of eight WCVM research teams that will conduct their investigations over the next 18 months. The studies’ topics range from veterinary oncology, internal medicine and medical imaging to pain control and zoonotic disease.

What’s the best dosing regimen for fentanyl in cats?
Drs. B. Ambros, P. Dowling, A. Livingston and T. Duke

Fentanyl is a common opioid, but the ideal dosing regimen of fentanyl infusions in cats is still unknown. Researchers will evaluate the analgesic effects of fentanyl infusions in conscious cats by measuring their pain thresholds and by documenting their behaviour. This data will help to establish accurate and appropriate dosing regimens for fentanyl as a pain reliever.

Researchers will begin by using a mechanical and thermal threshold device to determine the average pain threshold for eight healthy adult cats. Each animal will then receive a loading dose of fentanyl or saline solution followed by a continuous rate infusion of the same solution for five hours. Thermal and mechanical thresholds will be measured and blood samples will be collected at pre-determined intervals during the infusion as well as up to eight hours after.

Results will show fentanyl’s degree of analgesia and pharmacokinetic characteristics during the infusion. Researchers will also assess the accumulation of fentanyl and remaining analgesia after treatment and document behavioural side effects resulting from fentanyl continuous infusions in cats.

What’s the best indirect device for evaluating blood pressure in cats?
Drs. A. Carr, K. Parker, E. Snead and L. Weber

Accurate blood pressure measurements are critical for assessing, treating and maintaining the health of pets. Cats are particularly challenging because of their high heart rates and small peripheral arteries. Hypotension (low blood pressure) can cause tissue damage and a decreased ability to recover from trauma while hypertension (high blood pressure) can cause problems like chronic renal failure.

This study will compare the blood pressure measurements of anesthetized cats using a direct method (via an arterial catheter) to those obtained using indirect devices including an ultrasonic Doppler, HDO, VetGard, PetMap and DATEX.

After anesthetizing six healthy adult cats, researchers will insert arterial catheters and use them to take direct blood pressure measurements. They’ll then test each indirect device by taking at least eight measurements at each of three locations — a forelimb, a dorsal pedal artery and the tail — and comparing with the concurrent direct readings.

To determine when the devices are most accurate, they’ll repeat these measurements after inducing both hypotensive and hypertensive states in the animals. Their results will indicate the reliability of each indirect blood measurement device – valuable information for clinicians monitoring blood pressure.

What’s the best way to control dogs in northern communities?
Drs. T. Epp, E. Jenkins and C. Card

Overpopulation of feral, semi-feral and pet dogs on many First Nations reserves results in significant problems that include canine-related infectious diseases, transmission of zoonotic diseases and injuries to humans.

To facilitate a sustainable, community-led solution, researchers will begin establishing relationships with interested First Nations communities and assisting them in defining and addressing their dog issues. The team will use household surveys and medical examinations to characterize the dog populations and will meet with community members to explore options for dog control measures.

Solutions may include measures such as registration fees and leash or confinement laws as well as medical approaches such as injectable contraception, surgical alterations and vaccination and deworming clinics.

Once communities implement these programs, the research team will document and compare population changes annually to determine their effectiveness. This information will be valuable to other communities and to veterinary associations seeking effective strategies for delivering services to remote areas.

Can a Holter monitor help to detect heart problems in cancer patients?
Drs. V. MacDonald, A. Carr and K. Elliott

Chemotherapy drugs can damage the heart by causing an abnormal or irregular heartbeat called an arrhythmia. Doxorubicin, an effective and commonly used chemotherapy drug, has been associated with arrhythmia and injury to the heart (cardiotoxicity) in both humans and dogs.

A Holter monitor is a portable device that records cardiac activity — providing an electrocardiogram (ECG) for 24 or more hours. If it can detect and provide information about arrhythmias in dogs, the monitor will be an important tool for early detection of cardiac damage resulting from chemotherapy agents.

Researchers will attach ECG electrode patches to canine cancer patients so that Holter analysis can occur during each dog’s chemotherapy session and, whenever possible, for several hours after. The data will indicate arrhythmias occurring during the infusion of the chemotherapy drug as well as over the long term, particularly after repeated sessions.

Study results will help to establish the value of Holter monitoring for detecting arrhythmias and for predicting cardiotoxicity. This baseline data will also help researchers to evaluate prospective treatments that can minimize or eliminate heart damage.

Should three-view abdominal radiographs be recommended?
Drs. T. Silver, J. Pharr, A. Adrian and J. Lawson

Radiographic imaging is the least invasive and most accessible tool for clinicians evaluating the canine abdomen. Standard practice for radiographic studies entails two views — one with the animal on its side (either left or right) and one with the animal on its back. This study will determine whether three views including both sides would significantly improve radiographic interpretations.

Researchers will perform radiographic and computed tomography (CT) imaging studies to characterize three views of the normal abdomens of eight healthy dogs. Three experienced investigators will independently analyze each radiographic and CT study separately. They’ll describe each organ — visibility, apparent size, and other characteristics such as gas volume and distribution in the bowel.

Using the CT analyses to confirm any structures that are unclear in the radiographs, they’ll then review their findings together to characterize the normal abdomen in each position — information that’s useful for clinicians interpreting abdominal radiographs and for further studies evaluating animals with abdominal disease. Researchers will then determine whether to recommend that all baseline radiographic abdominal studies should consist of three views rather than two.

What are the reference values for arterial blood gases in older dogs?
Drs. E. Snead, H. Burgess, T. Carr and J. Pharr

Because older dogs represent an increasing proportion of the pet population, clinicians frequently have to interpret laboratory data related to their respiratory health.

This study aims to identify age-related changes and establish normal reference values for the arterial blood gas (ABG) tensions and thoracic radiographs of healthy geriatric dogs. Researchers will also investigate whether sex, obesity and environmental factors affect the animals’ ABG values.

The research team will assess 60 healthy geriatric dogs and classify them as lean or morbidly obese based on their body weight and body condition score. They will then analyze and compare their ABG values to those of 20 young adult dogs, attempting to match the animals according to weight. A radiologist will review the animals’ thoracic radiographs in order to document and classify any normal age-related pulmonary changes.

Using information from owner questionnaires, the scientists will also investigate the influence of environmental factors on the ABG values and thoracic radiographs of the geriatric dogs. The study’s results will help clinicians assess respiratory health and treatment options for their geriatric patients.

What are the effects of treadmill exercise on healthy dogs?
Drs. S. Taylor, C. Shmon and A. Carr

Many dogs are affected by an exercise intolerance syndrome. Current research has focused on establishing strenuous exercise protocols relevant to canine athletes and working dogs, but there’s a need for guidelines applicable to the general dog population.

Researchers will collect blood samples from each of 14 healthy Labrador retrievers before attaching an ECG (electrocardiograph) unit and administering an ingestible temperature sensor. A rectal temperature probe will also be inserted. Rectal temperature, telemetric core temperature, heart rate and rhythm will be recorded at regular intervals before, during and after exercise.

The animals will walk on the treadmill for five minutes and run for 10 minutes. Blood samples will be collected immediately after exercise and again at 30 and 60 minutes post-exercise. Researchers will videotape exercise and recovery as well as scheduled reflex and gait assessments.

Establishing baseline parameters for healthy conditioned Labrador retrievers will be valuable to future studies on collapse syndrome. Data collected while continuously monitoring body temperature during exercise is also significant to investigating whether exercise-induced hyperthermia and heat stress play a role in exercise intolerance disorders.

Can researchers “turn off” cancer cell growth?
Drs. Vikram Misra, Kathleen Linn, Valerie MacDonald and Elemir Simko

Cancer is devastating to humans and animals, and although progress has been made in treating primary tumours, cancer cells still spread to other sites in the body causing secondary tumours.

An insufficient oxygen supply (hypoxia) has been found in most tumours and is strongly linked with tumour development, growth, metastasis and poor response to therapy. The unfolded protein response (UPR) is one of three signalling pathways that regulate the cell’s response to hypoxia. Developing unique drugs and gene therapy for suppressing the UPR could effectively control the growth and spread of cancer in animals and humans.

In this study, researchers will use the canine genome database to develop and test genetic probes for monitoring components of the UPR in dogs. They will then use these probes to examine components of the UPR in various canine tumours and adjacent normal tissue.

Investigators will also monitor normal and tumour cells infected with vectors that express Zhangfei — a recently identified protein that may effectively turn off the genetic response that activates UPR.

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