Oligonucleotides of the formula 5'-(CAP)-(Oligo)-(CAP)-3' are disclosed where (oligo) is a nucleotide sequence of from 10 to 40 nucleotides in length, and CAP is G.sub.m, where m is an integer of from zero to ten, the two CAP's which are present in the molecule can be defined independently of each other and must be different in the case where m is zero at the 5' or 3' end and the end of the Oligo sequence is other than guanine. The oligonucleotides can be synthesized chemically. The oligonucleotides are used to diagnose or treat cancer, restenosis, a disease caused by a virus, a disease affected by integrins or cell-cell adhesion receptor or a disease triggered by diffusible factors.