The effect of sleeve gastrectomy on GLP-1 secretion and gastric emptying: a prospective study.

BACKGROUND: Rapid gastric emptying has been proposed to justify the increase in glucagon-like polypeptide-1 (GLP-1) after laparoscopic sleeve gastrectomy (LSG). OBJECTIVES: To assess gastric emptying changes after LSG and their relationship with GLP-1 secretion. SETTING: San Salvatore Hospital general surgery unit, University of L'Aquila, Italy. METHODS: 52 patients underwent gastric emptying scintigraphy for liquid and solid foods, before and 3 months after LSG. Twenty-six patients were in the liquid group (L group) and the remaining in the solid group (S group). We evaluated the half time of gastric emptying (T1/2) and percentage of gastric retention (%GR) at 15, 30, and 60 minutes for liquids and at 30, 60, 90, and 120 minutes for solids. GLP-1 plasma concentrations were measured in each group before and after LSG and related to %GR. Statistical analysis was performed by Χ2 test and Pearson correlation(r). RESULTS: After surgery, T1/2 was significantly accelerated: 15.2±13 min and 33.5±18 min in the L group and S group, respectively (P<.05). In both groups, GLP-1 plasma concentrations were increased at each blood sampling time: 2.91±2.9 pg/mL, 3.06±3.1 pg/mL and 3.21±2.6 pg/mL at 15, 30, and 60 minutes, respectively, (P<.05) for L group and 2.72±1.5 pg/mL, 2.89±2.1 pg/mL, 2.93±1.8 pg/mL, and 2.95±1.9 pg/mL at 30, 60, 90, and 120 minutes, respectively, (P< .05) for the S group. After LSG, GLP-1 and %GR presented a negative linear correlation (r) at each blood sampling time in both groups. CONCLUSION: The rapid gastric emptying 3 months after LSG upregulates the production of GLP-1 in the distal bowel. Further studies are needed to confirm these findings.

Validation of a two-generational reproduction test in Daphnia magna: An interlaboratory exercise.

Effects observed within one generation disregard potential detrimental effects that may appear across generations. Previously we have developed a two generation Daphnia magna reproduction test using the OECD TG 211 protocol with a few amendments, including initiating the second generation with third brood neonates produced from first generation individuals. Here we showed the results of an inter-laboratory calibration exercise among 12 partners that aimed to test the robustness and consistency of a two generation Daphnia magna reproduction test. Pyperonyl butoxide (PBO) was used as a test compound. Following experiments, PBO residues were determined by TQD-LC/MS/MS. Chemical analysis denoted minor deviations of measured PBO concentrations in freshly prepared and old test solutions and between real and nominal concentrations in all labs. Other test conditions (water, food, D. magna clone, type of test vessel) varied across partners as allowed in the OECD test guidelines. Cumulative fecundity and intrinsic population growth rates (r) were used to estimate "No observed effect concentrations "NOEC using the solvent control as the control treatment. EC10 and EC-50 values were obtained regression analyses. Eleven of the twelve labs succeeded in meeting the OECD criteria of producing >60 offspring per female in control treatments during 21days in each of the two consecutive generations. Analysis of variance partitioning of cumulative fecundity indicated a relatively good performance of most labs with most of the variance accounted for by PBO (56.4%) and PBO by interlaboratory interactions (20.2%), with multigenerational effects within and across PBO concentrations explaining about 6% of the variance. EC50 values for reproduction and population growth rates were on average 16.6 and 20.8% lower among second generation individuals, respectively. In summary these results suggest that the proposed assay is reproducible but cumulative toxicity in the second generation cannot reliably be detected with this assay.