The study also raised the possibility that the procedure might be harmful.

The study raises important questions that cry out for further research.

Other researchers said the study raised more questions than it answered.

An initial study last year raised similar concerns in the same kinds of patients.

These researchers say the study raises many more questions than it answers.

But a large study published last week raises questions about the test's usefulness.

More than one scientific study has raised questions about the value of sports drinks.

The study also raised concerns about the cost to universities.

"In either case, this study raises serious questions about the quality of our health care system."