Driven by a mother's love and a penchant for publicity, Maria DeSillers defied all tradition of parental patience and forbearance in the wait for donor organs to try to save her 7-year-old son, Ronnie.

One year after her only child's death despite three liver transplants, DeSillers still is fighting. But public sentiment is no longer on her side, and her battle has moved into Pennsylvania's civil courts and attracted the attention of Florida legal authorities."I sit here with pictures all over the walls of my son. I sit here and I've lost him and I'm fighting for other people's kids and I'm being criticized," DeSillers said in a telephone interview from Miami. "To have people criticize me without knowing all the facts, it's very painful."

With the first anniversary of Ronnie DeSillers' death on Friday, falling coincidentally within National Organ and Tissue Donor Awareness Week, she said it hurts even more.

"April 29th means a year and it hasn't gotten any easier for me," she said. "When I see kids playing, I get very emotional. Everything brings back memories. One thing I keep hearing over and over is Ronnie saying, `Mommy, I love you with all my heart.' "

The 32-year-old former public relations consultant, who is divorced from Ronnie's father, has withheld $261,189 owed Children's Hospital of Pittsburgh, the world's leading liver transplant center. She alleges her son's third transplanted liver was defective and that a potential fourth liver was turned down the day he died.

The hospital, which stands by its care of the boy, is suing DeSillers for the money.

"His treatment was beyond criticism. We still don't succeed in all cases, although we do in the vast majority," said Dr. Thomas E. Starzl, director of transplant surgery at Children's and its affiliate, Presbyterian-University Hospital. "We can't match the anguish a bereaved mother would have. But there's a very real pall of sadness that settles over us" when a patient dies. The controversy surrounding Ronnie's case "only amplifies the scar" and "cheapens" the boy's memory, Starzl said.

Hoping to spur a federal investigation of Children's Hospital, DeSillers last month released a series of internal memos in which anesthesiologists criticized the liver transplant program.

The memos complained of poor communication among doctors, inadequate review of failed cases and general confusion. One memo cited a case in which two livers were "switched about like peas under shells." A member of Pittsburgh's transplant oversight committee, an advisory group of two general physicians and six civic leaders, later explained the livers were swapped for medical reasons and that both operations succeeded.

In Florida, meanwhile, officials are investigating the way DeSillers handled the hundreds of thousands of dollars Ronnie received from countless Americans, including President Reagan, a fund that provided the initial $163,113 payment to the hospital.

A state audit this year put the total amount DeSillers deposited in seven accounts at two Florida banks at $980,310, a figure DeSillers says is far too high.

The money poured in after $4,000 collected by Ronnie's classmates was reported stolen in February 1987, a burglary still under investigation by Fort Lauderdale police.

Even after arriving at Children's with her increasingly ill son, DeSillers championed his cause like few parents before. On television shows and in frequent calls to reporters, she also stressed the need for organ donation and spoke out on behalf of others awaiting transplants.

By the time Ronnie died, the single bank account in his name had accumulated $509,913, according to Fred Kerstein, chief of the economic crimes division in the Office of the State Attorney in Miami. As of mid-February, the balance was $239,288, he said.

Those assets were frozen last month by a Dade County judge who appointed a curator for the estate.

Kerstein says DeSillers spent at least $47,000 of the missing money on jewelry, clothes, furniture, a BMW automobile and a Biscayne Bay apartment. He declined to break down that figure or elaborate on additional expenditures because of his office's investigation into possible fraud and other criminal violations.

DeSillers says she never squandered any of the donations and gave as much as $175,000 to families of transplant patients.

She says she bought her 1984 BMW at an auction for $13,000 and her one-bedroom apartment doubles as her office, which she furnished with a computer and other equipment. The apartment rents for $850 a month, but she says her one-year lease includes three free months.

Some of her own money was deposited with the donations, she says, and she used it to buy back jewelry she had pawned to pay medical bills. She says she also used some of the money to repay loans she took out to get Ronnie to Pittsburgh.

"People don't realize I was not an accountant and I was not an attorney and I did not have guidebooks," she said.

DeSillers is appealing a $1,000 fine for violating Florida's Solicitation of Charitable Contributions Act, which mandates that solicitations for single individuals go solely to the beneficiary. She maintains she never asked for donations but received them through sympathetic news accounts.

Reacting to the furor, a Florida Senate committee approved a bill on April 20 to more strictly regulate charitable contributions.

DeSillers has also been criticized for paying herself $300 a week as president of the Ronnie DeSillers National Foundation. "I was working 17 hours a day," she said in her defense.

The doubts and bitterness raised by the DeSillers case have hardly been a boon to organ donation.

"It has made people even more suspicious of the transplant field in terms of fairness and equity, and I think therefore it has had a dangerous effect on the willingness of people to be organ donors," said Arthur Caplan, director of the Center for Biomedical Ethics at the University of Minnesota.

On the other hand, Caplan said, "the case highlights the inadequacy of the way in which we fund innovation and progress in medical research. Families shouldn't need to beg for money or depend on charity."

The DeSillers case has also made fund raising more difficult, according to Mary Ann Lunde, chairman of the National Organ Transplant Education Foundation in Fort Lauderdale.

"It's sort of heart-breaking when you think about how this community (south Florida) responded to Ronnie DeSillers' needs and now it's having the opposite, negative impact," Lunde said.

DeSillers is chronicling her and Ronnie's struggle in a book she began writing four months ago. She says it includes "everything that happened in the hospital: names, dates, circumstances."

"I know there's a reason for everything that happens, and I know in the end, out of the ashes, comes the phoenix," she said. "I know in the end, it will be for the good of other children that Ronnie died."