Repole Stable's dynamic duo of UNCLE MO (Indian Charlie) and STAY THIRSTY (Bernardini) were out for some exercise Wednesday morning at 8:30 a.m. (EDT) in the allotted 15-minute period reserved for Kentucky Derby (G1) and Oaks (G1) hopefuls following the Churchill Downs' renovation break.

Uncle Mo, last year's juvenile champion, had exercise rider Hector Ramos up and assistant trainer Mike McCarthy alongside on a pony, while Stay Thirsty, the winner of this year's Gotham S. (G3), was partnered by Fernando Espinoza.

The two colts briefly stood in the starting gate and jogged an easy mile around the Churchill strip, which was dry and fast on a chilly spring morning. Trainer Todd Pletcher went frontside to observe their training and pronounced all well upon his return to Barn 34.

"Everything went smoothly," the multi-Eclipse Award-winning trainer said. "They handled their jog and the gate with no problems. We've done a lot of good training with them over the last several weeks here and we're just going light and freshening them up a bit coming up to the race. They'll gallop on Thursday and Friday and then that will be it."

Pletcher noted that he paddock-schooled Stay Thirsty on Tuesday, though that was not the case with Uncle Mo.

"Stay Thirsty got all hot and washy on us in (April 3) Florida (Derby [G1])," he said. "We wanted to give him a chance to get back in the paddock and feel comfortable, which he did yesterday. With Uncle Mo, there's no need to go to the paddock with him. He's very professional with all the things he does and he has never turned a hair in the paddock. He just doesn't need it."

John Velazquez, the only rider to sit on him during his five-race career, will once again be in the saddle for Uncle Mo Saturday. Ramon Dominguez, who has handled Stay Thirsty in his past two outings, including the Gotham score, has the assignment once more.

DIALED IN (Mineshaft) schooled in the Churchill Downs paddock Wednesday morning before galloping under exercise rider Carlos Correa. The Florida Derby winner has trained on a different program than Nick Zito's other Derby starters. The focus for the dark bay, who arrived from at Churchill from his South Florida winter quarters on Saturday, has been more on galloping and less on workouts.

"With a horse like this, he's not very big. We had a really good place to train on at Palm Meadows on a very heavy racetrack. He's a lightly raced horse, very lightly raced," the Hall of Fame trainer explained. "Even Uncle Mo, who has only raced two times (this year), he's had three races (as a two-year-old). Actually, they were three major races. Dialed In had one major race in November.

"Uncle Mo had a race in August when he won by a pole, then he came back and won the Champagne (G1) and won the Breeders' Cup (Juvenile [G1]). He had a lot of bottom. This horse didn't have much bottom running right into the Holy Bull (G3), a very big allowance race against older horses and then the Florida Derby."

Dialed In has become "ripped" through the program that included a lot of jogging and galloping with well-spaced workouts.

"Horses are gifts, horses this good. When you get a gift like this, you've got to figure out how to train this particular horse," said Zito, who has saddled two Derby winners -- Strike the Gold in 1991 and Go for Gin in 1994. "That's how we do it. Every horse, you couldn't train like this."

Dialed In, who captured the Holy Bull at Gulfstream in his second lifetime start, broke his maiden at Churchill Downs last November in his career debut.

"We were pretty high on him from Day One, but you have to see them run. I told a bunch of people I liked this horse," Zito said. "So when the day came and he ran and he broke not as good as he could break and he was way back and was kind of  in trouble and kind of did this and did that and then he just came running, we got excited."

Julien Leparoux, who rode Dialed In for his debut and three races at Gulfstream this year, has the return mount.

PANTS ON FIRE (Jump Start) galloped 1 3/8 miles with Juan Pizarro up during the Derby-Oaks training session, according to trainer Kelly Breen.

"I think it was possibly his best day of training," Breen said. "He really floated over the track. He was tough to pull up, he was eager to do everything. He started reminding me of what he did before the Louisiana Derby (G2) so I'm tickled pink right now."

Pants on Fire turned a corner at the Palm Meadows Training Center while preparing for that million-dollar race and delivered a gutsy performance in New Orleans, holding off Nehro (Mineshaft) in the final sixteenth despite looking beat coming into deep stretch.

Much of the credit for Pants on Fire's game finish went to 23-year-old jockey Rosie Napravnik, who was aboard the colt for the first time that day and will retain the mount for the Kentucky Derby. The decision was not necessarily an easy one for Breen, whose first-call rider Joe Bravo was atop Pants on Fire in the first two of Fair Grounds' trio of graded three-year-old stakes, but jumped off for entrymate Nacho Business in the Louisiana Derby.

"You win a million-dollar race and the rider did nothing wrong," Breen said. "Not to say that Joe couldn't get it done before, because every race is a different set of circumstances. Whether it was that she was in the right place at the right time, or the horse and Rosie click, I don't know. George and I talked about it right after the race and the day after the race and it's hard to take somebody off after they win our biggest race. George had never won a million-dollar race; I had never won a million-dollar race. We're just going to keep going with keeping it all the same."

Coming into the Louisiana Derby, the trainer felt fortunate to land Fair Grounds' runaway leading rider, who was en route to becoming the first female leading rider in the track's 139-year history with 110 wins at the 83-day meet.

"Rosie was known as being in the zone, doing everything right," Breen recalled. "Whatever it was, she was winning. Everything was clicking. When you see things as a rider that are about to happen before they happen, that's when you're in the zone. You know where to be, how to be, what's the good part of the track.

"She knows how to win and that's a big factor, when it comes to riders that are riding with confidence. We caught her at the right time. She's a patient rider and she knows what she's doing.

"For as young as she is she has great composure. She doesn't seem to get excited. You can see some of the things in how she rides are like her personality. When she gets in a tough spot she doesn't get overly excited. She can sit. From what I've seen I don't think anything gets to her."

Trainer Kathy Ritvo had a smile on her face when MUCHO MACHO MAN (Macho Uno) returned to Barn 41 on Wednesday morning after a "strong" two-mile gallop under exercise rider Mike Herra. The South Florida-based trainer was obviously pleased with her colt's preparation for Saturday's Kentucky Derby, but she has a much, much bigger reason to enjoy the whole experience.

"I'm so proud to be in the Derby, so blessed to be here, but just to get up every morning is amazing. It's amazing," said Ritvo, who was near death 2 1/2 years ago when she received a heart transplant that gave her a new appreciation for living life one precious day at a time.

Ritvo, who suffered from a degenerative heart disease that took the life of her brother, Lou, in 1996, will saddle her first Kentucky Derby starter, but the 41-year-old trainer has already won the most important race of her life.

"It's definitely prepared me better, because I don't worry as much. One day at a time, that's it. I think everything moves smoother when you don't worry about things," the mother of two said. "I don't worry about it. I'm very serious about my job and what has to happen with the horse, but other than that, I don't worry about it. It's all good."

Ritvo spent six months in the critical care unit of Jackson Memorial Hospital in Miami before receiving the transplant.

"It was definitely emotionally exhausting because it was hard to keep fighting it mentally," she said. "When I was in the hospital, people would come into the room and ask, 'How are you doing?' I don't know how you answer a question like that. You're either waiting to die or waiting to live."

Ritvo, whose Derby horse captured the Risen Star S. (G2) at Fair Grounds, is happy to be alive and live to inspire others.

"If I can give any hope, anytime I can say something, if they're sick and waiting for a transplant, I just want to tell them to hold on, because this is a good life," said Ritvo, who takes eight anti-rejection pills at 7:30 a.m. and another eight at 7:30 p.m., as well as 15 vitamins during the day.

The Boston native doesn't know anything about the donor or the donor's family.

"I wrote a Thank You letter and sent it out and I didn't receive anything back yet. Maybe some day, but I respect their privacy. Maybe some day," she said. "You never know the situation. I think if you think about it too much, it'll drive you crazy. I'm just grateful. It's going to happen at the right time, or it won't. I think it's going to happen at the right time."

In other Derby news:

U.A.E. Derby (UAE-G2) runner-up MASTER OF HOUNDS (Kingmambo) walked the shedrow of Barn 45 Wednesday while serving his mandatory quarantine period.

The bay was flown from Ireland to Louisville Tuesday morning and T.J. Comerford, traveling head lad for trainer Aidan O'Brien, said everything was going well and the colt was settled in.

"He's just having a walk under tack in the barn for three-quarters of an hour to an hour," Comerford said. "He will walk again this evening and will go out to the track in the morning. He's good, very good."

Master of Hounds will clear the quarantine period in time for training hours Thursday. Comerford said the plan is to take him to the track at 8:30 during the period reserved for Oaks and Derby horses.

"He'll do his own little jog and a canter around," Comerford said. "The next day the same. That will just take the edge, the freshness out of him."

This is Master of Hounds' second visit to Churchill Downs. He was the beaten favorite in the Breeders' Cup Juvenile Turf (G2) on November 6. His lone start of 2011 was in the U.A.E. Derby, where he was caught at the wire, losing by a nose. His only victory in seven starts was in a maiden race, but he has three seconds and a third and has started in three consecutive graded stakes on as many continents.

"He's good. There are no problems with him," Comerford said. "He's very straightforward."

California speedster and Grade 1 scorer COMMA TO THE TOP (Bwana Charlie) went trackside for the first time on a chilly Wednesday morning at Churchill at 8:30 following the renovation break. The gelding had a pony at his side and trainer Peter Miller up for a jog of about a mile around the big oval. The horse, who'll be the most experienced runner in Saturday's Derby 137 with 13 starts already to his credit, had flown in from his Southern California base Tuesday.

"He went fine," the 44-year-old Miller said back at Barn 42. "He shipped fine and seemed to enjoy the track this morning. I've gotten on him on occasions (in California) before, just like I like to get on all my horses every once in a while. It helps me get a feel for them; to see how they're doing."

Miller, a former groom and exercise rider, has been training on his own since 2004. This is his first Kentucky Derby experience.

"I'll paddock school him this week," Miller said. "Not today, but maybe Thursday and Friday. One or two days of that, we'll see."

California-based Patrick Valenzuela, who won the 1989 Kentucky Derby on Sunday Silence, has the call on Comma to the Top.