Dear Doctor: I know I need to eat more vegetables, but because I have dentures, I can't chew them well enough to swallow easily. I have particular problems with celery, lettuce, oranges and tomato skins. If I were to "masticate" them in a food processor, would I still get the benefits, or would the processor blade destroy too many cells?

Dear Reader: We see you're familiar with two indisputable facts when it comes to living with dentures: First, the way they function is different from our original teeth. Dentures rely on a seal to stay in place, so you have to be careful about the types of foods you eat. Texture (think nuts or steak or seeded breads) and the angle of attack (like an apple or corn on the cob) can wreak havoc on both the seal that keeps the dentures in place, and sometimes the dentures themselves. Second, these challenges don't have to be a barrier to the foods you want to eat. As your question illustrates, a bit of creative problem solving can add to the diversity of the foods in your diet.

While there's a certain logic to the idea that using a food processor to chop or mince or emulsify a food can adversely affect its nutritional content, the good news is that's not the case. What appliances like food processors and blenders do first and foremost is to alter a food's texture and, of course, its appearance. And let's agree that we're not talking about juicing here. That's the process in which the liquid content of a food is extracted and the resulting pulp, the food's fiber content, is left behind. That's an entirely different process with outcomes that merit a separate discussion. (Drop us a line if you're interested.)

Digestion begins the minute food enters the mouth. Teeth pulverize the bite into smaller pieces and particles and mix it with saliva, all of which jump-starts the process of dismantling the food on a chemical level. The lion's share of the work of breaking down the bonds between food molecules takes place after you swallow, carried out by powerful enzymes in the stomach, and trillions of friendly bacteria in the intestines. What you're proposing is to get a head start on the chewing process with the help of a food processor. Depending on the blade you use, you can slice, chop, pulverize or puree.

The act of slicing, chopping or pureeing food doesn't change its nutritional value. However, once a food is broken down, the nutritional clock does start ticking. That's because a wide range of nutrients found in vegetables and fruit are sensitive to air and light, as well as to heat. When you put an item through the food processor, it's a good idea to eat it the same day. Wrap any leftovers tightly and refrigerate.

In general, remember to chew on both sides of your mouth when you're living with dentures. Dental adhesives can help when a saliva seal proves inadequate. As you've shown, with preparation and imagination, dentures needn't be an impediment to a balanced and interesting diet.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Could you tell me about the causes, treatment and remission rates for Burkitt lymphoma?

Dear Reader: Burkitt lymphoma is a highly aggressive, rapidly growing type of B cell lymphoma. It's caused by an alteration to a gene involved with cell division and cell death. The alteration of this gene causes B cell lymphocytes (a type of white blood cell) to divide quickly and repeatedly, creating multiple abnormal cells.

There are three types of Burkitt lymphoma, and the likelihood of each one depends on your geographic region and your immune status. In Africa, the incidence of Burkitt lymphoma is 50 times higher than in the United States, with the disease there caused largely by chronic Epstein-Barr virus infection. In this type of Burkitt lymphoma, the peak incidence of infection is between the ages of 4 and 7. Often, the disease is initially found in the bones of the face or jaw; from there it can spread to other parts of the body.

The most common type of Burkitt lymphoma in the United States is much rarer -- about three cases per million people per year -- and the peak incidence is about 11 years of age, with the majority of cases occurring in people younger than 35.

The third type of Burkitt lymphoma occurs in people with a suppressed immune system, usually due to HIV infection. In these cases, the suppression of the immune system causes viruses, like Epstein-Barr, to exert genetic changes on B cells that lead to lymphoma.

Because Burkitt lymphoma is a rapidly growing cancer, chemotherapy works well against it, and multiple drugs are available to stop its growth and destroy the rapidly growing B cells. In fact, because drugs are so effective, radiation and surgery are not generally recommended. Of note, many chemotherapy regimens now include the medication Rituxan, often used for rheumatoid arthritis, because of its ability to attack B lymphocytes. Because Burkitt lymphoma can often make its way to the brain, most chemotherapy treatments are also given via the cerebrospinal fluid by way of a lumbar puncture.

Chemotherapy is not without its side effects. Part of the difficulty in older adults, especially those over the age of 60, is the ability to tolerate these side effects. They include bone marrow suppression, in which the numbers of red and white blood cells and platelets drop dramatically. The drop in the white blood cells can make a patient more susceptible to severe bacterial infections. Chemotherapy can also lead to toxicity of the heart and the nerves of the body.

As for survival rates, those depend on the regimen of chemotherapy and the age of the patient. A study from Germany found that people ages 15 to 25 had a five-year survival rate of 90 percent; the rate decreased to 84 percent in people ages 26 to 55, and to 62 percent in those over 55.

You didn't say whether you or someone you know is being treated for Burkitt lymphoma, but, if so, I hope this limited review has been helpful.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My 81-year-old father is scheduled for a heart procedure, and I'm actually less worried about the surgery itself than the effects of the anesthesia. I've read that it can lead to memory loss in the elderly. Is there any way to help him?

Dear Reader: The condition you're referring to is known as postoperative cognitive dysfunction, sometimes shortened to POCD. It's loosely defined as impairment to the mental functions of an individual following surgery performed under general anesthesia. And while your question zeroes in on anesthesia as the cause of those cognitive side effects, the jury is still out on that. Some researchers point to the rigors of surgery itself as well as the body's resulting inflammation response as contributing factors to the condition.

Symptoms of POCD include impaired memory, difficulty learning and retaining new information, a shortened attention span, problems carrying out more than one task at once and a decline in the ability to concentrate. These can develop over time following surgery and may last a few weeks, a few months or in some cases become permanent. While the condition can occur in any surgical patient, it's most often seen in elderly individuals.

One of the challenges to diagnosing POCD is that unless the patient has undergone pre-operative cognitive testing, assessing his or her post-operative condition relies on observational and anecdotal evidence. In cases where the syndrome is pronounced, a reliable diagnosis can be made. But in more subtle cases, where those around the patient feel he or she has "lost a step" following surgery, citing POCD as the direct cause becomes more difficult. With that in mind, we'd like to share with you the following recommendations from the American Society of Anesthesiologists:

-- Before surgery, undergo a cognitive test that can be used as a baseline against which to compare similar post-surgical testing, if needed.

-- Make sure your surgeon is familiar with all medications and supplements you're taking in the weeks and days before surgery, and any that you plan to take following the procedure. This includes medications to address pain, sleep and anxiety.

-- Patients who wear glasses or use hearing aids find it easier to re-enter the post-surgical world when their sight and hearing are at optimal levels. Assign someone the task of making them available to you as soon as possible following surgery.

-- Arrange for a caregiver, who can notice and report any troubling symptoms, to visit with you regularly as you recover.

-- Anchoring yourself in the present as soon as possible after surgery is important. Request a room with a window, so you have visual cues regarding the passage of time, as well as your physical location.

-- In that same vein, photos of family, friends and pets, familiar possessions, and a clock and a calendar, all can help you readjust.

With an aging populace, many of whom will go on to require surgery, recognizing and preventing POCD is rapidly becoming a public health issue. A wide range of researchers are now focused on it. As new findings emerge, we will share the latest information.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)