A doctor who attempted to tamper with the scales at a championship fight weigh-in had his cornerman's license revoked Thursday by the Nevada Athletic Commission.

Dr. Armando Barak was accused of placing his foot under the scale as Jose Luis Castillo weighed in at Caesars Palace the day before his Oct. 8 lightweight title fight against Diego Corrales. Barak was trying to make Castillo appear to weigh less than he actually did.

Barak, Castillo's training camp physician, was responsible for the fighter making weight.

He also was supposed to serve as Castillo's cutman on fight night but was banned by commission executive director Marc Ratner after the weigh-in incident.

Castillo failed three times to make the lightweight limit of 135 pounds, weighing 138 1/2 on his final attempt.

The fight then became a nontitle match, which Castillo won on a fourth-round knockout.

Barak vehemently denied the allegations, saying he accidentally bumped the scale and apologized to Ratner for doing so. But Ratner, who was conducting the weigh-in, told the commissioners he saw Barak place his foot under the scale.

"It was not a bump," Ratner said. "I heard a noise and I saw his foot under the scale. It was not flat. It was lifted. It was one of the most egregious things I have ever seen."

The commission voted to revoke Barak's license until Oct. 9 and ordered him to pay all the hearing costs.

Barak produced a witness, Francisco Andujo-Soto of Mexicali, Mexico, who said Ratner never looked down when Barak bumped the scale.

Castillo had stripped completely nude at the weigh-in in an effort to make weight and Andujo-Soto was holding a towel in front of Castillo.

But the commission gave little credence to Andujo-Soto's testimony.

Commissioner Joe W. Brown said, "I don't believe him."

Each of the commissioners went to lengths to praise Ratner's integrity.

Also on Thursday, the commission revoked the license of kick boxer Sean McCully.

McCully tested positive for the anabolic steroid nandrolone after a fight in Las Vegas on Sept. 11, 2004.

He appeared at a hearing on Sept. 21, 2005, in which he apologized for using steroids and said he was clean of both steroids and marijuana. He had also tested positive for Delta-9-THC, the active agent in marijuana, after the bout on Sept. 11, 2004.

At the 2005 hearing, McCully agreed to take a steroid test that day to back up his assertion that he was clean but failed to do so.

He later submitted a urine sample that showed no traces of steroids, including endogenous steroids that are naturally produced by the body.

Dr. John Hiatt of Quest Diagnostics testified the sample was not urine.

"This was missing (the endogenous steroids), and the only way that happens is if someone submits a sample that is not really urine," he said. "You can buy fake urine, but those samples are designed to help someone pass drug tests, not steroid tests.

"I concluded this is a false sample prepared and sold for the purpose of avoiding a legitimate drug test result."

McCully said, "I plead the fifth on this one" and that he was going to retire. The commission then revoked his license.

The commission lifted the suspension of UFC fighter Nathan Marquardt, who tested positive for nandrolone after an Aug. 6 fight in Las Vegas.

Marquardt said he took a supplement he bought at a health store and didn't know it contained the steroid.

Also, the commission re-elected Skip Avansino as its chairman.