The official line from the mayor's office: Bob O'Connor is fully in charge, despite undergoing chemotherapy for brain tumors that started yesterday.

		Online graphic: Mayor Bob O'Connors top advisers Mayor weathers first chemotherapy well

The reality: No mayor is fully in charge, and even less so when they're gravely ill.

Mr. O'Connor "has a lot of good people there, and that's important, because nobody knows everything," said Sophie Masloff, who was president of City Council when Mayor Richard Caliguiri was sick, and replaced him when he died in 1988.

"No question about it, Pittsburgh [has] a strong mayor" under its charter, she said. When Mr. Caliguiri fell ill with the rare disease amyloidosis, there was a leadership vacuum, she said.

Yesterday, mayoral spokesman Dick Skrinjar maintained that the administration was not naming an acting mayor, and that staff members' roles weren't changing.

He said no one will pretend they can replace the mayor as the public face of city government. But staff will continue tightening the nuts and bolts of government.

"We'll use this time to refine and craft legislation and policy initiatives for the fall," he said. Aides and department heads will work on streamlining government and preparing a five-year financial plan and a 2007 budget.

One key to success when Mr. Caliguiri was ill, according to Mrs. Masloff: "The staff members were pretty cooperative and worked with each other" rather than competing for turf.

Much responsibility for making sure that happens again could fall to Chief of Staff B.J. Leber, 51. The mayor's reduced presence could test her ability to work the levers of power.

She's relatively new to municipal government, and also to Mr. O'Connor's inner circle. Her career includes stints as an executive in public broadcasting, at the Port Authority, and in the media.

She would say nothing yesterday about whether her role would be affected by the mayor's battle with cancer.

Yesterday, she and Director of Intergovernmental Relations Dennis J. Regan met to work on the proposed sale of some 20 Downtown properties to developers Millcraft Industries and Ira M. Morgan, according to Mr. Skrinjar. Ms. Leber is chairwoman of the board of the city's Urban Redevelopment Authority, which controls the properties.

Mr. Regan, 53, said yesterday that his duties and schedule have been "regular, day-to-day" since Mr. O'Connor was first hospitalized on Thursday.

"I just deal with [Allegheny] County, Harrisburg, the governor's office, that's what I do. Legislators, council," he said.

But he is viewed as a person with the mayor's ear.

Along with city Senior Secretary Marlene Cassidy, with whom he shares a Point Breeze home, he is among the handful of administration members who have been at the mayor's side since his first bid for the office in 1997.

He also chairs the board of the Pittsburgh Housing Authority.

If the mayor at some point expects to become temporarily unable to perform the duties of the office, he must appoint a deputy to serve in his stead. Neither Ms. Leber nor Mr. Regan could fit the bill, since only a "major administrative head" can do so under the city charter. City Council members take the position that it must be someone who has been confirmed by that body.

That means city Solicitor Susan Malie, Finance Director Paul Leger, Public Works Director Guy Costa, Director of Community Initiatives Duane Ashley and a handful of others would be eligible.

Ms. Malie has been named deputy mayor when Mr. O'Connor has traveled. A city lawyer since 1991 and the daughter of a firefighter, the 38-year-old knows the bureaucracy well.

She has had some public profile this year as one of the negotiators of new contracts with city paramedics and refuse workers.

Mr. Costa, 50, is a well-known face to Pittsburghers, and has political connections, with two brothers in the state Legislature. But he faces his own health issues, having been diagnosed last year with a low-grade glioma, a slow-spreading, curable brain tumor.

Mr. Ashley, 53, is a holdover from Mayor Tom Murphy's administration. Mr. Leger, 61, had an 18-year city career that ended in the mid-1990s, and was tapped to return in April. Both have toiled quietly during this administration.

City Council members yesterday said their body would do nothing different as a result of the mayor's illness.

"I have regular dialogue with the mayor's office and have a good working relationship," said council President Luke Ravenstahl. "I anticipate that business will continue to operate on a normal schedule. I think the mayor himself would want that."

The 26-year-old would become mayor if Mr. O'Connor was unable to complete his term. Politically, he faces the challenge of appearing able to fill that post, without appearing at all eager.

Mr. O'Connor "is going to come out of this thing with as strong a personality as he ever had," Mr. Ravenstahl predicted yesterday.

Mrs. Masloff said it would be tough for someone as young as Mr. Ravenstahl to take the wheel of a city still struggling financially. She remembered her own trepidation when Mr. Caliguiri's health faltered.

"Mayor O'Connor made a good start," she said. "We really have to stay optimistic."