Columbia University has been testing at its health center since 1986.

County officials have tested the river regularly since last summer.

They had been tested since March in some smaller publications.

Smith said tonight that she had been tested out of competition four times since May and denied using drugs.

Only 140 existing chemicals have been tested since 1993, the commission said.

Various versions of the Champ have been tested and produced since 1944.

Nixon had been tested two or three times a week ever since his arrest on a possession charge in 1987.

Some of the most poignant have come from England, where the drug has been tested the longest, since 2001.

The program has been tested in Seattle since November 1988.

Three cows in Canada have tested positive for mad cow since 2003.