(AREA) -- The Michigan appeals court has ruled to limit the use of a landmark court decision that ends mandatory no-parole sentences for juveniles convicted of murder. The state court in a decision dated Thursday and released Friday says a major U.S. Supreme Court decision from earlier this year should not apply retroactively to Michigan inmates who already have exhausted most appeals. The Michigan Court of Appeals ruled in the case of a St. Clair County man, Raymond Carp, who was convicted of a murder committed when he was 15. His lawyer, Patricia Selby, says they're both "very disappointed" by the decision. More than 350 prisoners in Michigan are serving mandatory no-parole sentences for murders committed when they were under 18. That's one of the highest totals in the U.S.