Early-phase insulin hypersecretion associated with weight loss outcome after LSG: a prospective cohort study in Asian patients with BMI ≥28 kg/m2.

BACKGROUND: Obesity has become a global problem that poses a serious threat to human health. Laparoscopic sleeve gastrectomy (LSG) is an effective long-term treatment. However, the weight loss of some patients after LSG is still insufficient. It is necessary to investigate the factors associated with inadequate weight loss after LSG. OBJECTIVE: The objective of this study was to explore whether preoperative insulin secretion could be associated with weight loss after LSG in patients with obesity. SETTING: This is a single-center prospective cohort study conducted in a university hospital. METHODS: Patients from a prospective database who underwent LSG were analyzed. All 178 participants underwent a 75-g oral glucose tolerance test (OGTT) to assess preoperative insulin and c-peptide secretion before LSG. The areas under the curve (AUCs) for glucose, insulin, and c-peptide were determined in the OGTT. The percentage of excess weight loss (%EWL) and the percentage of total weight loss (%TWL) were used to estimate the effect of weight loss after LSG. Regression models were used to assess the correlation between preoperative insulin and c-peptide secretion with %EWL ≥75% and TWL ≥35% at 12 months after LSG. RESULTS: The AUCs of insulin and c-peptide were significantly lower in the %EWL ≥75% and %TWL ≥35% groups at 0-30 minutes, 0-60 minutes, and 0-120 minutes during the OGTT. At 30, 60, and 120 minutes during the OGTT, c-peptide levels were significantly lower in the %EWL ≥75% group and %TWL ≥35% group. The preoperative c-peptide level at 30 minutes during the OGTT (C30) was significantly negatively correlated with %EWL (ß = -.37, P < .001) and %TWL (ß = -.28, P = .011). Univariate logistic regression analysis showed that preoperative C30 was associated with %EWL ≥75% and %TWL ≥35% after LSG. According to multiple logistic regression analysis, patients with a low preoperative C30 had an 8-fold higher %TWL ≥35% after LSG than those with a high C30 (odds ratio: 8.41 [95% confidence interval: 1.46-48.58], P = .017). Similarly, patients with a low preoperative C30 had a 7-fold higher EWL% ≥75% after LSG than patients with a high C30 (odds ratio: 7.25 [95% confidence interval: 1.11-47.50], P = .039). CONCLUSIONS: The rate of weight loss after LSG is low among patients with preoperative hyperinsulinemia. The preoperative c-peptide level at 30 minutes during the OGTT is associated with weight loss after LSG.

[Diagnosis of Argon Metastable State in Low Pressure DBD Plasma Using Diode Laser Absorption Spectroscopy].

Gas temperature and density of Ar metastable state in DBD Ar (Ar/N(2)) plasma were measured using the tunable diode-laser absorption spectroscopy technology at low pressure. The variation trend of the densities of Ar metastable state 1s(5), 1s(3) and gas temperature with voltage, pressure, gas flow, electrode distance and N(2) concentration was studied. The density of Ar metastable was obtained by calculating the absorption peak area of absorption line based on the Lambert-Beer law, while gas temperature was determined with Doppler width of the absorption line in Voigt fitting. We deduced that the main source of the Ar metastable was the electron-impact excitation from the ground state, and the main loss process was the electron quenching. In addition, the actual discharge power, the electron state and the collision between particles were responsible for the variation of gas temperature. It was found that, when the voltage and gas flow increasing, both temperature and densities of 1s(5), 1s(3) shown the similar trends, which increasing rapidly at first and then slowly. In addition, the variation with gas flow was smaller than that with gas flow. With pressure increasing, temperature and densities of 1s(5), 1s(3) increased till to a max value and then decreased. Meanwhile, the experimental data indicated that the pressure had a greater effect on spectral line width. To increase the electrode distance properly, the density of 1s(5), 1s(3) decreased while the gas temperature increased. N(2) added to Ar presented a great negative effect on the density of Ar metastable state. Even 0.5% N(2) added to Ar, the densities of 1s(5) and 1s(3) decreased rapidly about to 50%, but then more N(2) added, there was no obvious decrease about density.