The following data is included with samples: Age / gender / size / weight at time of operation / Results of a serologies to be included (HIV 1&2, HBV et HCV) On an empty stomach at the time of surgery: Insulinemia / Blood sugar / HbA1c / Cholesterolemia / Triglyceridemia / HDL- Cholesterol If diabetic: Years of diabetes / Therapeutic class used to treat diabetes