Keratin cover grows to protect

By: BRADLEY J. FIKES - Staff Writer | Saturday, October 14, 2006 6:31 PM PDT ∞

The death of a body part is almost always bad news. Not the nails. These protective ends to the fingers and toes are formed from cells whose whole goal is to sacrifice themselves for the good of the rest.

Whether on fingers or toes, nails are made the same. The exterior is mostly a hardened, compressed protein called keratin. This keratin forms the tough nail plate. It comes from cells called keratinocytes, which also make up most of skin and hair.

Nail keratinocytes begin growing in the matrix, a part of the nail plate hidden by the cuticle. As the nail keratinocytes grow, they are pushed out past the cuticle, dying and becoming compacted as they grow. At the beginning, just past the cuticle, the nail is whitish in a crescent shape. This is called the lunula. At the end, the nails form an edge that can help in grasping small objects.

Continuously self-regenerating, nails grow about 0.1 millimeter per day, or about 1.4 inches a year. But this continuity can be interrupted by injury to the matrix or illness. This can produce white spots or other irregularities. These grow out as the nail regrows, and are not usually a problem.

A major injury can totally stop keratinocyte growth, causing the loss of the entire nail. It will fall off and the finger or toe will need extra protection until a new nail grows out. If it grows out. Sometimes an injury or even exposure to the wrong chemical can cause permanent nail loss.

A January 1980 article in the Journal of Dermatologic Surgery and Oncology described one case of chemical-induced nail loss. It described a patient's allergic reaction to methyl methacrylate, used in making acrylic plastics. The chemical, ironically enough, was in a mixture used to make artificial nails.

"Gradual destruction of the nail plates developed, and since no regrowth of the nails resumed in six years, the loss of the fingernails is found to be permanent," the article stated.

Healthy nails are smooth, of a uniform color, and without ridges or grooves, according to the health site Mayo Clinic.com (www.mayoclinic.

com). However, vertical ridges may appear normally as you age. A yellow or green discoloration may be caused by bronchitis or another respiratory disease.

Other advice from Mayo Clinic.com:

You can help keep your nails healthy with a minor amount of routine maintenance. Regularly trim the nails and clean under them. The nail edges should be trimmed with clippers or manicure scissors, and smoothed with an emery board to eliminate pesky jagged edges.

Don't bite your nails or pick at your cuticles. Those habits can injure the nail bed and allow a bacterial or fungal infection. Such infections can turn the nails ragged, and turn the underlying nail bed green, brown or black. That's cause to see a dermatologist.

Severe cases of ingrown toenails, with pain, spreading inflammation or pus, likewise demand a visit to the doctor. Mild cases of ingrown toenails can be treated by soaking feet in warm salt water for 15 to 20 minutes twice a day. Other self-treatment includes putting fresh pieces of cotton underneath the toenail to guide it to grow outward, applying antibiotic ointment and wearing open-toed shoes or sandals.

And don't pull off hangnails -- you'll cause even more damage. Instead, just clip off the hangnails, leaving a tiny nubbin. This leaves a clean edge that will heal faster.

Moisturize your nails, preferably at the same time you moisturize your hands. Just rub the same lotion you use into the nails. Use the moisturizer each time you wash your hands. And protect hands and nails alike with cotton-lined rubber gloves when using soap and water for long periods, such as dishwashing, or when using harsh chemicals.

Nails should be kept short. Cut them in a square shape, with the edges slightly rounded. Splits or tears can be repaired with nail glue or clear polish.

Most people have an adequate diet for healthy nails. Protein won't help, because most people in the United States get plenty of protein. Soaking nails in gelatin also does no good.

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.