Or so I had thought.

A brief article in the June 5, 2009 issue of The Week has given me a reason to look harder at the quality of life of my cancer patients. It also has given me another reason to hate cancer–as if I needed one.

Tumors are doubly depressing

A diagnosis of cancer is obviously a good reason to be depressed. But new research finds that the feeling isn’t just psychological: Tumors produce high levels of a chemical that can effect [sic] mood and make people feel down. Behavioral neuroscientists at the University of Chicago compared depression and anxiety rates in groups of rats with and without tumors. Since rats have no awareness that they have cancer, Dr. Brian Pendergast tells BBCnews.com, “their behavioral changes were likely the result of purely biological factors.” He found that rats with cancer exhibited signs of depression and anxiety, floating passively when placed in water while cancer-free rats swam for safety. The tumor-ridden rats also hoarded and buried objects they were given, and lost interest in eating sweets. The scientists believe that the anxious and depressive behavior is connected to levels of chemicals called cytokines, which are produced by tumors and also by the immune system when it’s battling cancer. Rats with tumors had double the normal level of cytokines, which have a direct, depressing effect on emotional centers in the brain.

Note that this study does not say anything specifically about dogs or cats. But it does give me an additional reason to hope that some major breakthroughs in cancer research will come soon. For the record, I think they will.

Also, be aware that a great deal of research currently is directed towards understanding and modifying cytokines (cytokines are linked to pain and a number of other physiological responses that might be modifiable through pharmaceuticals). However, in the case of cancer, there is no doubt that the best approach is not to target cytokines. The best tactic is to cure the disease.

Photo: Transposagenbio. License: CC.

Scott Seymore was debating whether to euthanize his 9-year-old bulldog, Brittney, who was dying of stomach cancer. Instead the Grand Rapids, Mich., man decided to give Brittney steroids to ease her pain in her last few weeks of life. Seymour’s decision paid off last week when his house caught fire and a barking Brittney woke him up. Both master and pet escaped safely. “She never, ever barks when I’m sleeping,” said Seymour. “She was demanding that I get up. And it saved my life.”

Human medical advances historically have been the basis of veterinary medical advances. New human treatments are often adapted to animals.

But a report in Science Daily shows that sometimes it can be the other way around.

The story describes a new treatment for a serious form of canine cancer: anal sac adenocarcinoma. Anal sac adeoncarcinomas are aggressive tumors with limited treatment options. Or rather, the options used to be limited.

A new treatment has been developed. It relies on the fact that tumor cells have extra receptors for vitamin B12. In the treatment a relatively benign molecule, nitric oxide, is attached to vitamin B12. The nitric oxide is toxic to cancer cells. It has little impact on the rest of the body.

Since humans don’t have anal sac glands (and therefore we don’t suffer from anal sac adenocarcinomas), it may seem that this treatment wouldn’t be of much interest to the field of human medicine. However, our tumors often have extra vitamin B12 receptors. This means that, with some gentle manipulation, the therapy may some day be useful to us as well.

It’s a win-win situation, to be sure.

A recent article in The Economist describes yet another way that dogs may soon help people. Certain breeds may serve as research models for hereditary diseases.

A DOG may be man’s best friend. But man is not always a dog’s. Over the centuries selective breeding has pulled at the canine body shape to produce what is often a grotesque distortion of the underlying wolf. Indeed, some of these distortions are, when found in people, regarded as pathologies.

Dog breeding does, though, offer a chance to those who would like to understand how body shape is controlled. The ancestry of pedigree pooches is well recorded, their generation time is short and their litter size reasonably large, so there is plenty of material to work with. Moreover, breeds are, by definition, inbred, and this simplifies genetic analysis. Those such as Elaine Ostrander, of America’s National Human Genome Research Institute, who wish to identify the genetic basis of the features of particular pedigrees thus have an ideal experimental animal.

Dr Ostrander has already used dogs to track down the genes behind certain cancers that the species shares with people, and to work out the dog family tree. At the [American Association for the Advancement of Science] she described her search for the genes controlling three of the most important features of a breed: its size, its hair and the length of its legs.

What is the relevance of looking at dogs’ leg length? It turns out that chrondrodysplasia, which is what causes Dachshunds and Corgis to have short legs, may be caused by the same set of genes that triggers what is “known vulgarly as dwarfism” in humans.

The upshots of this work are twofold. One is to show that a lot of variety can be caused by only a little genetic variation . . . [t]he second upshot is that dogs may cast light on the condition of human chondrodysplasics and thus prove, once again, what good friends they are to man.

I should add that I, like many men in their thirties, also can think of at least one very solid upshot to studying the growth of hair in dogs (or any species)!

Click on the humanhealth tag for more posts on the health benefits that humans derive from pets.

All pet owners and most in the medical community now acknowledge the healing power of animals. Some doctors even write prescriptions giving hospitalized patients access to the pets they left at home. At the 1,000-bed Christiana Hospital in Newark, Del., patients can request orders for a recuperative in-room visit with their pet.

But there are pockets of disagreement among doctors when it comes to allowing seriously ill or functionally fragile people to return to a home occupied by a pet buddy. Some advise pets be exiled, fearing that someone in a full-leg cast, for example, might trip over a rambunctious cat and undo everything; or someone with open wounds or whose immune system is weak from chemotherapy or diseases like HIV/AIDS could pick up an infection from the animal.

I understand that allowing gravely ill people to visit with pets carries risks. But time spent with pets may also be beneficial. Pets create a sense of well-being. They reduce stress (which helps the immune system). They give people something to live for, and they motivate people to get well.

I have discussed the human health benefits of pets on many occasions. Check out the humanhealth tag on this blog for a sampling. Here is my take: pets are good for people.

The author of the article in USA Today seems to agree. Here is another excerpt:

Indeed, a growing body of anecdotal data suggests time with a pet may be “as powerful in the person’s recovery as the medical treatment,” says the American Humane Association’s Phil Arkow.

American doctors regularly prescribe placebo pills that are intended to have a psychological effect, a new survey finds. . .

The placebo effect, well-established in countless studies, is a benefit produced by assuring someone that whatever is being given will benefit whatever the problem happens to be — “optimism or confidence that something is being done,” as [Dr. Farr A.] Curlin phrased it.

What the article says, in essence, is that when people go to the doctor, they want to be cured. Many people feel neglected if they do not receive some form of treatment or medicine.

This happens in veterinary medicine, as well. As I mentioned in my first and second articles on the little-known side effects of common medications, practicing clinicians often write prescriptions that will not truly affect a patient’s condition except through the placebo effect. However, when these medicines are prescribed, side effects are possible.

In some cases, veterinarians write needless prescriptions because clients pressure them to do so. In other cases, the pressure comes from inside the vet. Vets want to feel like they are working to cure their patients. They sometimes dispense a medicine even though it isn’t truly appropriate for the condition.

I have most regularly witnessed this phenomenon in the treatment of feline asthma. Mild cases of feline asthma cause occasional coughing. Many cats with mild asthma don’t need daily treatment. They would be better off without medication.

However, quite a few mildly asthmatic cats are placed on antihistamines such as diphenhydramine (Benadryl) or chlorpheniramine (Chlortrimeton). In theory, this makes sense. Asthma in cats is caused partly by allergies.

However, numerous studies have shown that these two antihistamines have no effect whatsoever on the clinical course of feline asthma. Prescribing these medicines makes vets and clients feel like they are helping cats. That is how the placebo effect works in veterinary medicine. In reality, the medicines do nothing but annoy the cats and put them at risk of side effects.

Before you accept a medication for your pet, talk to your vet. Make sure that the medication is truly appropriate for your dog or cat. Don’t give your pet placebos.

Acetaminophen is extremely toxic to cats. It has limited uses in dogs.

Although the drug is generally considered safe for people, several side effects are widely known. Liver damage is a well-publicized side effect from acetaminophen ingestion.

The October 10, 2008 issue of The Week contained a blurb that described a new discovery. Here is an excerpt.

A five-year study of 200,000 babies and children has shown that if an infant is given acetaminophen, her or she is 46 percent more likely to have developed asthma by 6 or 7.

Acetaminophen is a human medicine. The study involved children, not pets. What does this have to do with a vet blog?

In practice, I sometimes am pressured by clients to prescribe medications for syndromes that will spontaneously resolve. These clients want to feel like they are doing something to make their pets better.

I admire their desire to help their pets. However, I am very reluctant to prescribe a drug unless I have a strong reason to believe that the medicine will make a positive difference.

Acetaminophen has been on the market for 53 years, and possible side effects are still being discovered. That is a solid reason not to overmedicate my patients.

The article touches on my all-time favorite subject: the physical and emotional health benefits that people derive from animals. Many of these benefits are well documented. People who have dogs benefit from increased exercise. Petting cats lowers blood pressure. Therapy dogs in children’s hospitals make patients want to get well. They also make the work environment more pleasant for nurses. Pets may be able to detect abnormal blood sugar levels in humans with diabetes. The list goes on and on.

Now we can add two new documented ways that animals help people. Dogs may help relieve the symptoms of post-traumatic stress disorder in veterans. They also serve as assistance animals for veterans who have gone through limb amputations.

Here is an excerpt from the article.

A couple of months ago, [Abelardo Rosas] barely spoke to anyone. He was sullen and surly and not responding to treatment at the PTSD clinic at the Veterans Affairs health center in Menlo Park.

Then he met Vegas, a sweet, good-natured golden retriever with a shiny coat and sad eyes.

Rosas had volunteered to participate in a pilot program – veterans at the clinic would train canines to become assistance dogs to aid disabled veterans, those who had lost limbs or are confined to wheelchairs.

The story proceeds to describe how the companionship of Vegas helped Rosas re-gain a sense of balance in life. He also helped the young veteran to feel relevant and helpful again.

[Rick Yount, director of the program] said handling and training dogs is valuable in the treatment of PTSD because the animals help the veterans connect with their emotions. The dogs counteract feelings of isolation. They have to take the dogs out into the community, he said, and other people inevitably want to pet the dogs and talk to the person handling them.

“The dog also reinforces the need to assist someone else,” he said. “This is important for a lot of veterans because most of them joined the military to help people.”

In my opinion it is an absolutely ingenious program. My hat goes off to everyone involved in it!

The book, by Marion Nestle, is titled Pet Food Politics: The Chihuahua in the Coal Mine. It discusses the infamous pet food recall of 2007. In the incident, melamine-tainted pet food sickened and killed thousands of animals.

A main thesis of the book is that the problems that occurred in 2007 should serve as a wake-up call. If contaminants such as melamine can make their way into pet food, they can make their way into human food.

Ms. Nestle’s advice could not have been more timely. This month it surfaced that melamine-contaminated milk powder has sickened thousands of infants in China. Several have died.

And today a breaking news report revealed that melamine has been discovered in Cadbury chocolate.

At this time the extent and severity of the chocolate contamination are not known. But this incident does a great deal to prove that animal and human food safety are interlinked.

As I mentioned in a previous post, research (supported by the American Veterinary Medical Association–I occasionally have my differences with the organization, but I should emphasize that it also does a tremendous amount of good work) concluded that animals were sickened by a combination of two chemicals in the contaminated food: melamine and cyanuric acid.

Melamine is a chemical normally used in the manufacture of fertilizer and chemicals. It can be used, nefariously, to boost the measured levels of protein in foods when they are tested.

Cyanuric acid is a byproduct of shoddy melamine production. The combination of cyanuric acid and melamine causes crystals to form in the kidneys of mammals, leading in some cases to kidney failure.

Or, to put it another way (what follows are unproven allegations): the manufacturer involved in last year’s pet food recall appears to have used melamine to make wheat flour appear to be higher in quality than it actually was. However, that manufacturer appears to have been too cheap to purchase high-quality melamine. The low-quality melamine used to throw off protein testing contained cyanuric acid. The combination of melamine and cyanuric acid sickened and killed pets.

Now, a similar process appears to be happening to humans. Infant formulas tainted with melamine have been linked to illness in thousands of infants in China. Several deaths have been attributed to the formulas.

I have yet to see cyanuric acid mentioned in any article related to this newest scandal, but I suspect that time will show that it, too, is involved in the problem.

It’s a sorry situation. My heart goes out to the parents of all affected individuals–dog, cat and human.