Eugene E. Campbell, who pleaded guilty to seven rapes in connection with assaults on women in Southeast Washington, was sentenced in D.C. Superior Court yesterday to serve 35 to 105 years in prison.

Chief Judge Harold H. Greene sentenced Campbell, 21, as an adult after lawyers for the city's Public Defender Service argued unsuccessfully that their client could benefit from treatment that would be available to him if he were sentenced under the Youth Corrections Act.

Attorney W. Gary Kohlman argued that if Campbell was sentenced under the act, he could still receive a lengthy prison term, but also would benefit from counseling and psychiatric services at an appropriate federal institution.

"I'm sorry, I'm really sorry this happened and I would like to go someplace and get help," Campbell told Greene before sentencing.

Assistant U.S. Attorney Martin J. Linsky told Greene that Campbell should be given a "substantial adult sentence" for "protection of the public." The offenses occurred between December 1974 and June 1976.

The youth act provides that in most cases, persons should be released by the time they are 26 years old. However, a section of the act does allow for longer periods of imprisonment in some cases, the U.S. attorney's office said.

Before he imposed the sentence, Greene noted that the U.S. Parole Commission, in a strongly worded letter, had recommended that Campbell be sentenced as an adult because he would not benefit from provisions of the Youth Corrections Act.