What is the appellant's response to our request for an independent review of the record on appeal?

We appointed counsel to represent appellant in this matter. After examining the record, counsel filed a "Wende" brief raising no issues on appeal and requesting that we independently review the record. (People v. Wende (1979) 25 Cal.3d 436.) We directed appointed counsel to immediately send the record on this appeal and a copy of the opening brief to appellant and notified appellant that within 30 days from the date of the notice he could submit by brief or letter any grounds of appeal, contentions or argument he wished us to consider. We received no response from appellant.