11.   Thus far, efforts to use viruses as carriers to introduce healthy genes to replace the defective ones that cause cystic fibrosis have not worked very well.

12.   To give the panther population an infusion of healthy genes, biologists this past year released eight female cougars from Texas into three southern Florida parks.

13.   An aerosol spray containing a healthy gene could help alleviate one of the dangerous abnormalities that appears in cystic fibrosis, a new study says.

14.   An experimental new gene-therapy technique has proved it can safely deliver a healthy gene and shows promise as a treatment for hemophilia, researchers report.

15.   Just four days before his death, University of Pennsylvania scientists had placed healthy genes in his liver to combat a rare metabolic disease.

16.   Just three patients were injected with a healthy gene to stimulate production of a blood-clotting protein.

17.   Some healthy genes actually were transferred.

18.   The success of gene therapy depends greatly on the introduction of a healthy gene to correct the action of the disease-causing defective gene.

19.   The treatment entails slotting in a healthy gene to replace a defective one, with the idea of preventing or even reversing an inherited illness.

20.   Under the genetic treatment at Auckland Hospital here, healthy genes take over from faulty ones and halt deterioration of the nerve cell sheaths.