Obesity, MorbidGastroplastyGastric BypassObesityBiliopancreatic DiversionBariatric SurgeryAnastomosis, Roux-en-YWeight LossLaparoscopyJejunoileal BypassBody Mass IndexAvitaminosisHalf-LifeArea Under CurveSurgical StaplersPostoperative ComplicationsJejunumStomachGastrectomyMetabolic Clearance RatePharmacokineticsBody WeightBiological AvailabilityAdministration, OralElephantiasisIleumVitamin B DeficiencyTreatment OutcomePrader-Willi SyndromeObesity, AbdominalInjections, IntravenousDrug InteractionsLeptinPediatric ObesityMalabsorption SyndromesFollow-Up StudiesTime FactorsFatty LiverInsulin ResistanceInfusions, IntravenousDiabetes Mellitus, Type 2Adipose TissueTissue DistributionCross-Over StudiesReceptors, LeptinProspective StudiesMethodsComorbidityEatingRisk FactorsPostoperative CareDose-Response Relationship, DrugChromatography, High Pressure LiquidBlood GlucosePrevalenceFood-Drug InteractionsDigestive System Surgical ProceduresInsulinDrug Administration ScheduleMetabolic Syndrome XRetrospective Studies