Ghrelin, glucagon-like peptide-1, and peptide YY secretion in patients with and without weight regain during long-term follow-up after bariatric surgery: a cross-sectional study oleh Charalampos Lampropoulos, Francesk Mulita, Theodoros Alexandrides, Dimitrios Kehagias, Dimitra Kalavrizioti, Konstantinos Albanopoulos, Neoklis Georgopoulos, Evangelos Papachristou, Ioannis Kehagias