writes: Does a brace help in sciatica?

A back brace might help, depending upon the cause of sciatica.

writes: Does the cholesterol go down when most of the thyroid gland is removed?

No. It usually goes up. The cholesterol level in the blood is influenced by the glands of the body. It is low when the thyroid is overactive and high when the gland is sluggish. The latter is likely to occur when the thyroid is removed.

The gap between the bookshelf and the record cabinet grows smaller with each new recording catalogue.

There's more reading and instruction to be heard on discs than ever before, although the spoken rather than the sung word is as old as Thomas Alva Edison's first experiment in recorded sound. Edison could hardly have guessed, however, that Sophocles would one day appear in stereo.

If the record buyer's tastes are somewhat eclectic or even the slightest bit esoteric, he will find them satisfied on educational records. And he will avoid eye-strain in the process.

Everything from poetry to phonetics, history to histrionics, philosophy to party games has been adapted to the turntable.

For sheer ambition, take the Decca series titled modestly ``Wisdom.'' Volumes One and Two, selected from the sound tracks of a television series, contain ``conversations with the elder wise men of our day.''

These sages include poet Carl Sandburg, statesman Jawaharlal Nehru and sculptor Jacques Lipchitz, in Volume One, and playwright Sean O'Casey, David Ben-Gurion, philosopher Bertrand Russell and the late Frank Lloyd Wright in the second set. Hugh Downs is heard interviewing Wright, for an added prestige fillip.