Cancer cells and normal cells are known to respond differently to nutrients and drugs that affect glutathione status.

Numerous studies have shown that tumor cells have elevated levels of glutathione levels, which confers resistance to chemotherapy drugs.

One of challenges of cancer therapy is how to deplete tumor cells of glutathione, so as to make them more vulnerable to effects of chemotherapy drugs, while at same time allowing normal cells to remain relatively unaffected by chemotherapeutic drugs.

A number of new findings have emerged that take into consideration role of glutathione in pathways that promote programmed cell death (apoptosis) in cancer cells.

A German study has reported that glutathione (GSH) plays a critical role in cellular mechanisms that result in cell death. The study found that cancer cells resistant to apoptosis had higher intracellular GSH levels.

Depletion of glutathione in these tumor cells made them more vulnerable to effects of anticancer drugs or gene that promotes apoptosis (CD95 or APO-1/Fas). The researchers concluded that apoptosis resistance in tumor cells depends, at least in part, on intracellular GSH levels. (1)

In another study conducted in Spain, researchers found that lowering GSH concentration may be convenient not only for efficiency of chemotherapy, but also to induce a rather fast and direct apoptosis mechanism in tumor cells. (2)

Based on that premise that glutathione-S-transferase enzyme is expressed at high levels in many tumors, researchers at Fox Chase Cancer Center in Pennsylvania, went on to design a novel prodrug (PABA/NO).

The glutathione-s-transferase in tumor cells converts PABA/NO to lethal nitric oxide, resulting in death of tumor cell. The prodrug was shown to have antitumor effects in an animal model for human ovarian cancer. (3)

But imagine having unique challenge of not being able to, literally, "get up and go". This is unique challenge of more than 56 million disabled individuals in U.S. alone, many who are wheelchair users.

For many involved in mainstream fitness industry, term "wheelchair exerciser" may conjure up images of someone in a physical therapy setting in process of rehabilitation from injury or disability. But consider wheelchair user who wants to participate in regular exercise for weight loss or muscle gain. Or those with burning desire to compete in a favorite sport. What services meet their unique challenges?

Fortunately, there are many options that those in wheelchairs have in pursuing fitness goals:

Access to facilities

The Americans with Disabilities Act signed in 1990 helped increase availability of wheelchair-accessible facilities, including health clubs. As more and more private health clubs follow suit, individuals who use wheelchairs will have increasing options.

However, access alone does not ensure that wheelchair exercisers will have appropriate equipment to meet their strength training and cardiovascular needs. It’s easy enough to modify certain upper-body exercises with dumbbells and resistance bands for a seated exercise, but most machines simply will not accommodate a wheelchair. Effective aerobic training can be even harder to accomplish, since most cardiovascular machines require use of legs to raise heart rate.

Adaptive Exercise Machines

Fortunately, there is a large number of adaptable exercise machines available to exerciser and to health clubs that choose to offer adaptive exercise options:

The Endorphin Corporation http://www.endorphin.net/ Manufacturer of wheelchair accessible fitness machines for both cardiovascular and strength conditioning, including hand cycle and tabletop bike.

Access To Recreation http://www.endorphin.net/ Exercise equipment and recreational products for wheelchair-bound such as all terrain wheelchairs, pool lifts and more.

Spinlife http://www.spinlife.com/ Sells wheelchairs of all types. Contains resource section.

Adaptive Fitness Personal Trainers

Finally recognizing need for fitness professionals to be knowledgeable about needs of wheelchair exercisers, a number of personal trainer organizations offer specialized certifications and/or programs in Adaptive Fitness. This is good news for those who desire professional instruction by a trainer who is knowledgeable of special needs. The following are a few organizations that offer either certification program in Adaptive Fitness or specialized education:

International Sports Sciences Association (ISSA)/Specialist in Adaptive Fitness http://www.issaonline.com/courses/saf.cfm

American Association for Active Lifestyles & Fitness http://www.aahperd.org/aaalf emplate.cfm?template=adaptedaquatics.html

Exercise videos, TV Programs and Manuals

Some may feel more comfortable working out in privacy of their own home rather than travelling to gym. For those searching for in-home instruction, resources such as exercise videos, TV programs and printed instruction manuals can help wheelchair user increase activity levels, lose fat and gain muscle mass:

Armchair Fitness http://www.armchairfitness.com/ Classic armchair exercises developed by fitness expert Betty Switkes. Includes videotapes for aerobic, strength, yoga, and "gentle" formats.

Maria Serrao’s Workout Tapes http://www.dropbears.com/amazon emplate_movies ype_browse/mode_290298 Actress and model Maria Serrao, in a wheelchair since age of 5, stars in a series of exercise videotapes including: Everyone Can Exercise-Cardio Challenge, Toning & Strengthening, Real Life Fitness-Body Sculpting, Real Life Fitness- Fat Burning.

Sit and Be Fit with Mary Ann Wilson http://www.sitandbefit.com/ Seated exercise videos for older adults and/or physically limited individuals. Sit and Be Fit is also a cable TV series; broadcast schedule is listed on website.

Paul Gaudino's Family Fitness Show http://www.exerciseman.com/ Cable TV exercise show that features exercises for disabled, wheelchair bound, seniors, people with back pain, and beginners. Exercise videotapes are available through his website.

Creative Chair Exercises http://www.tudefitness.com/wheelchairexercisead.htm A Seated Exercise manual by Bob Blick, including both aerobic and strength formats.

The Thrill of Victory... Wheelchair Sports and Competition