A handful of new findings on cell transplantations are being presented this week at the American Heart Association's annual meeting in Chicago. Among the latest results:

* Nabil Dib, director of cardiovascular research at the Arizona Heart Institute in Phoenix, reports that he and his team have safely transplanted skeletal muscle cells into 16 people with severely damaged hearts. Eleven patients had the cells injected during bypass surgery. Five received the cells when doctors implanted a left ventricular device, a machine designed to keep them alive until a heart transplant can be found.

The transplanted skeletal cells "survived and thrived in patients," according to Dib. Weakened areas of the heart damaged by heart attack or other cardiovascular disease "showed evidence of repair and viability," he said, suggesting that it's possible to regenerate dead heart muscle or scar tissue "without increasing risk of death."

* British researchers at the University of Leicester said that they safely implanted bone marrow cells into the hearts of 14 heart attack survivors during non-emergency bypass surgery. Within six weeks of treatment, heart wall motion improved and persisted for at least 10 months , said heart surgeon Manuel Galinanes, an author of the study. Whether the bone marrow cells created healthy new tissue is yet to be proven, but Galinanes said that he believes "that is the only possible explanation."

* Japanese researchers reported yesterday that injections of bone marrow cells into the calf muscles of people with peripheral artery disease helped increase capillary growth compared with injections of harmless saline. The study, which is the first to randomly test bone marrow injections against saline, found that 31 of 45 people who received the bone marrow cell injections showed an improvement in ankle-to-leg blood pressure as early as four weeks after treatment, suggesting better blood flow because of the new capillaries. Walking pain and leg and foot ulcers also steadily declined throughout the 24-week study, the team reported. The findings point to "the clinical efficacy of growing new blood vessels using bone marrow cell transplantation," said lead author Hiroya Masaki, associate professor of laboratory medicine and clinical sciences at Kansai Medical University in Osaka.

* A French team of scientists headed by Philippe Menasche, professor of cardiovascular surgrey at Georges Pompidou European Hospital in Paris, is scheduled to present four reports this week on the use of cell transplantation in cardiac patients. One study includes the first results on the electrical effects in the heart by transplanted muscle cells. "We've definitely established that these cells survive in human heart tissue," said Menasche, who is credited with performing the first human cell transplantation to a heart in June 2000.