You're enjoying your vacation in the Alps or on Waikiki, but deep there are pangs of guilt because of those you left behind - like Twinkie, your faithful Pomeranian.

Oh, you've tried to do your best to enhance Twinkie's lonely days. You left him at Petropolis, the spacious new pet center in Chesterfield, Mo., where you've been assured that he will receive special attention in the Toy Dog Room.Twinkie has a canopied sleeping area in his cage and the owners have done their best to make the area homelike for all the lap-size doggies who couldn't make the trip. There's a couch and chairs and some lamps, and over in the corner there's a big TV set.

"We leave the set on most of the time," said co-owner Lorie Bugby, "especially when the soaps are on, because we figure the dogs are accustomed to that kind of noise.

"We encourage our staff to take their breaks or to study in the Toy Room, to provide human companionship. In addition, each dog is carried outdoors every two or three hours and allowed to play."

As a conscientious pet owner, you've gone an extra mile by making a videocassette of yourself that Petropolis employees play on the TV screen a couple of times a day.

"A dog gets very excited when he hears his owner's voice and sees him on the screen," Ms. Bugby said.

Still, as you frolic, you wish you could do something else to assure Twinkie that you care.

Then, inspiration. A post card! And when the card arrives, you know it will be read to Twinkie.

"The dogs sniff the card because they recognize the scent of their owner," Ms. Bugby said. "We clip it to a board just outside the cage."

The type of care available for lap dogs like Twinkie is typical of the services available at Petropolis. Despite the name, there is little that is Greek about the establishment, which prints "Pet" in a different color than "ropolis." Petropolis is a 22,000-square-foot center that opened last summer.

"This is the most sophisticated and advanced pet-care center in the world," said Ms. Bugby, who shares ownership with her son, Paul J. Schifano, a veterinarian.

Just don't use the term "kennel" - or you'll land in the dog house.

"We'd like our boarding area to be called a `pet hotel,"' Ms. Bugby said, "because the poor quality of service given by some operators has given the word `kennel' a bad connotation."

Animals that wouldn't fit on a lap reside in "condominiums" at Petropolis. These are two-room suites, "sleeping room" and "patio," that can be expanded to four or six rooms. Sometimes an owner with multiple pets will rent a large space and let the animals mingle.

Every imaginable type of medical facility is available in the area presided over by Schifano. The air in this section is pulled from other parts of the building and, to prevent the spread of infection, is never recirculated to other rooms.

"This is the X-ray room," Schifano said, pointing toward a sealed area. "For extremely complicated situations, we can even consult a radiologist who works with humans."

His mother, Schifano explained, is married to Dr. Robert Bugby, a Minneapolis radiologist. Lorie Bugby commutes between the two cities.

Moving right along in the spotless hospital wing, Schifano showed a visitor the ultrasound equipment ("mostly to determine if an animal is pregnant"), the surgery ("we use gas, rather than an injectable anesthetic, because it is safer and the animal wakes up sooner"), and an incubator ("for birds, which are so stressed that just touching them can be fatal").

In the dental section, a Yorkshire terrier rested in his cage. In a container lay a dozen teeth that had been extracted earlier. Schifano also does root canals and fills cavities.

"Most owners don't realize the importance of cleaning their pet's teeth," Schifano said. "It is difficult to use a brush, but we recommend massaging with finger gloves about three times a week. They sell five for a dollar and they have the paste implanted.

"Don't use humans' toothpaste. Animals swallow it and get sick. A digestible paste comes with the gloves and it can be made to taste like liver or many other exotic flavors."

The second floor includes a training arena the size of a basketball court, where several grades of canine education take place, from puppy training to preparation for competition.

Ms. Bugby ordinarily breeds a type of terrier known as dandie din mont, but at the moment her only pets are two parrots at the Minneapolis home where she and her husband and his three teen-age daughters live.