/ Dr Peto Says

Vet Care – Modern Medical Miracles

Published August 1, 2011 in Dr Peto Says |
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Every veterinarian offers basic care such as vaccinations, neuter surgery, and parasite control. But today, just as in human medicine, veterinary specialties offer modern techniques that go “beyond the basics.”

Here are just a few cutting-edge techniques now available to our feline and canine companions. Most are available only in speciality practices and university settings overseas. Ask your veterinarian if these or other procedures might have special benefit for your fur kids.

Back Injury Treatment
An innovative preventive procedure pioneered at Oklahoma State University called laser disk ablations treats dogs with a history of back pain. Instead of surgically removing damaged disks (as in conventional treatment), lasers zap the spinal needles inserted through the skin into the disks, to vaporize the problem material – no incisions, no muss, no fuss – and no disks left to prolapse. A number of specialty veterinary practices in the States now perform this procedure.

Bone Cancer Limb Sparing
Limb-sparing surgeries allow dogs and cats with bone cancer to keep the affected leg, rather than amputating the limb. Surgeons remove only the diseased bone. They then replace it with a donor bone from a deceased companion, or use a living section of bone from a healthy part of the companion’s leg. Other times, a metal rod takes the place of the bone. It takes about sixteen weeks for the graft to fuse to the dog’s existing bone and heal.

And in the most unbelievable medicine of all, the section of radius bone with the offending tumour is removed. Then a 2.5 cm section of healthy bone cut from the stump end is slowly moved 1 mm per day – prompting the healthy bone to grow/heal new bone in about 4 to 6 months.

Vision Surgery
Companions with eye injuries or ulcers benefit from corneal transplants performed by veterinary ophthalmologists. Older dogs may develop problems that cause the cornea to turn blue, and the small central portion is removed and replaced.

Cats sometimes develop eye problems resulting from chronic herpes virus infection that cause the cornea to turn brown and die. A partial thickness corneal graft can correct the defect, and in about six weeks the eye heals and looks clear and beautiful. Companions that develop cataracts also can benefit from the same surgery that treats people.

Kidney Transplants
Kidney transplant can save our companions’ lives. Cats seem particularly accepting of the procedure and do not have the high rejection rate the way dogs and people do. Do not worry, no kitties are killed to provide organs -instead, the feline that donates the kidney gets adopted as part of the arrangement. It has been reported that 59 percent of the cat transplant patients were still alive six months after surgery and 41 percent were still alive three years after surgery – some have lived for a decade or longer. About five universities and private specialty practices in the States offer cat kidney transplants.

Cartilage Transplant and Stem Cell Therapies
Arthritis, dysplasia and other joint problems damage cartilage and make movement painful. An innovative procedure patterned after human techniques harvests healthy normal cartilage (often from the patient’s other joints) and transplants it in plugs in the damaged area. The bone/cartilage plugs grow more cartilage, which spreads and covers the deficit.

Vet-Stem Regenerative Medicine employs a concentrated form of adult stem cells derived from the companion’s own fat tissue to treat tendon, ligament, and arthritic conditions of horses and dogs. The veterinarian collects about two tablespoons of fat from the patient, which is shipped to the Vet-Stem.com laboratory in San Diego, California. Once processed, the stem cells are shipped back to the veterinarian in ready-to-inject syringes, and the stem cell treatment is injected directly into the injured site. Any extra can be stored at the Vet-Stem Bank for future treatments.

Heart Repair
Open-heart surgery currently remains limited to a few universities in US, and UC Davis Veterinary Medical Teaching Hospital is the only place that has regularly scheduled procedures for animals. They can do pretty much any procedure performed on humans, and employ a cardiopulmonary heart-lung bypass machine that allows the heart to be stopped for one to two hours.

One surgical procedure replaces defective valves with cow or pig tissue. Leaking heart valves is common in small animals, especially very small dogs. Surgery requires a six- to nine-person team to carefully monitor the patient before and during the invasive surgery. The entire surgery lasts five hours or longer.

Some dogs now benefit from pacemakers. But the most common congenital heart disease, patent ductus arteriosus (PDA) affects miniature poodles and German shepherds most often. Texas A&M and other specialty practices use catheters (long flexible tube) threaded through the arteries to fix the problem, sometimes by placing stainless steel fibre-embedded coils into the hole. The fibres stimulate clotting, which shuts off the hole.

Research has led to new diagnostic tools, new surgical procedures, new prevention options, and new uses for existing or novel drugs. These innovative veterinary options not only save lives but also extend a companion’s longevity and improve the overall quality of life. And that is just doggone good for everyone!

Adapted from an article by Amy D Shojai


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Seeing Eye to Eye – Comparing Cat and Dog Vision

Published July 29, 2011 in Dr Peto Says |
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The eyes of cats and dogs are quite similar to our own, but how are they different? The cat has the largest eyes of any meat eater; if our own eyes were proportionally the same, human eyes would be twenty centimetres across. But it goes beyond the looks-pun intended. In fact, the way our companion animals see influences how they interact with each other – and with us.

Field of Vision
Prey animals like rabbits can watch in two directions at once with eyes on each side of the head. But predators-dogs and cats – have eyes toward the front of the face that gives them depth perception and binocular vision so they can correctly time pursuit and pounce.

Most dogs have only about 30 to 60 degrees of binocular overlap versus approximately 140 degrees cats and humans. But dogs are champions when it comes to visual field of view. That means when Fido looks straight ahead he can still see 240 degrees, compared to 200 degrees in cats and 180 degrees in humans.

Seeing 20/20
Dogs cannot focus clearly on objects closer than about 25 centimetres (which explains why Fido may miss the two or three pieces of kibble left in his bowl). Cats are a bit better at near vision. But both dogs and cats rely more on motion rather than focus, and are rather farsighted, an evolutionary side effect of scanning the distance for prey. A dog can detect strong hand signals from as far away as 1.6 kilometres.

The visual acuity of dogs is about 20/75, although German shepherds, Rottweilers and Schnauzers appear to be even more near sighted. Cats have dogs beat with an average acuity between 20/100 and 20/200.

Glasses?
Contact lenses can correct nearsighted vision in dogs. That can be important especially for service animals or hunting dogs. But contacts are not practical when dogs lose them so easily. Dogs do benefit from being fitted with glasses. A veterinary ophthalmologist evaluates vision by refraction in the same way non-verbal children are examined. Products like Doggles.com are designed to fit the canine face in all its various shapes and sizes.

Low Light, High Light
Like human eyes, the dog’s iris to contract the pupil to a round pinpoint that limits the amount allowed inside. The feline eye is a more complex figure-eight muscle that closes to a slit much further than the canine eye.

Both cats and dogs have a tapetum lucidum, a layer of highly reflective cells behind the retina that reflects back any light the eye captures. That produces the eerie night-shine can be seen from your companion’s eyes and is why cats require only 1/6th the illumination level and use twice as much available light as people. Dogs’ eyes are about half as efficient as the cats’ but still better at using light than humans.

Colour Perception?
Both cats and dogs have fewer specialize cone cells on the retina able to distinguish colours than people do. But they can see colour.

Dogs seem to be similar to people who are “red-green color-blind.” Cats probably see more in terms of blue/green shades and appear able to tell the difference between colours that contrast. For cats, pattern and brightness are more important than colour. They can see colour but it does not matter to them.

Peripheral Vision
Cats are experts at seeing motion from the corners of their eyes. Cats also have a highly specialized ability to make extremely rapid eye movements, which allows them to better detect and follow an object, such as a mouse or even a feather on the end of a string toy. But dogs beat out cats on peripheral vision.

Both cats and dogs have a high density line of vision cells across the retina, called a visual streak. That lets them see sharp focused object at a distance even in the extremes of peripheral vision-out of the corners of their eyes. Cats and dogs tend to ignore stationary objects but this visual streak triggers their instinctive urge to chase whenever something moves in their peripheral vision.

The visual streak is most pronounced in long-nosed dogs-the breeds developed to hunt and chase. But many of the short-nosed dogs like Pugs do not have this visual streak. Instead, they have high density vision cells arranged in a single spot on the retina, called the area centralis. The area centralis has three times the density of nerve endings as the visual streak. That makes short-nose dogs much better able to see and react to human facial expressions – or watch TV.

Adapted from an article by Amy D Shojai


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