Background The effects of gastric bypass surgery on the secretion of the anorexogenic gut-derived hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), independent of caloric restriction and due to different dietary macronutrients, is not well-characterized. This study examines the effects of a mixed-nutrient or high-fat liquid meal on the postprandial stimulation of GLP-1 and PYY following gastric bypass or equivalent hypocaloric diet. Methods Total PYY and active GLP-1 were measured fasting and at multiple points after standardized mixed-nutrient and high-fat liquid meals in two matched groups of obese subjects. The meal stimulation tests were performed before and 14.6±3.3 days after gastric bypass (GBP, n=10) and before and after a 7-day hypocaloric liquid diet matching the post-GBP diet (Control, n=10). Results Mixed-nutrient and high-fat postprandial GLP-1 levels increased following GBP (mixed-nutrient peak: 85.0±28.6 pg/ml to 323±51 pg/ml, p<0.01; high-fat peak: 81.8±9.6 pg/ml to 278±49 pg/ml, p<0.01), but not after diet (mixed-nutrient peak: 104.4±9.4 pg/ml to 114.9±15.8 pg/ml, p=NS; high-fat peak: 118.1±16.4 pg/ml to 104.4±10.8 pg/ml, p=NS). The postprandial PYY response also increased after GBP but not diet, though the increase in peak PYY did not reach statistical significance (GBP mixed-nutrient peak: 134.8±26.0 pg/ml to 220.7±52.9 pg/ml, p=0.09; GBP high-fat peak: 142.1±34.6 pg/ml to 197.9±12.7 pg/ml, p=0.07; diet mixed-nutrient peak: 99.8±8.0 pg/ml to 101.1±13.3 pg/ml, p=NS; diet high-fat peak: 105.0±8.8 pg/ml to 103.1±11.8 pg/ml, p=NS). The postprandial GLP-1 response was not affected by the macronutrient content of the meal. However, following GBP the mixed-nutrient PYY AUC0–120 was significantly greater than the high-fat PYY AUC0–120 (22081±5662 pg/ml•min versus 18711±1811 pg/ml•min, p=0.04). Conclusions Following GBP there is an increase in the postprandial stimulation of PYY and GLP-1 that is independent from caloric restriction. The phenomenon of ‘bariatric surgery-induced anorexia’ may be linked to the increased levels after GBP.

Lunch consumption decreased as a function of MPH dose. DA-related genotypes associated with greater brain DA signaling moderated the influence of drug on consumption. These results provide information relevant to predicting which children are likely to experience the greatest appetite suppression when taking MPH.

We examined in a group of 15-year-old adolescents the retest reliability over one week of 7 subscales of the Automated Neuropsychological Metrics (ANAM), a computerized battery based on standard neuropsychological test measures that is one of several such batteries available to assess concussion effects. Since the principle behind these computerized batteries is to assess athletes before injury and after injury to determine the level of deficit and whether the individual is safe to return to play, it is critical that such batteries have excellent retest reliability. Retest reliability of the ANAM was good, especially for the aggregate of throughput scores, reaching 0.87, but lower for individual subtests, especially for those measuring only speed of processing. Thus, the ANAM aggregated score appears to have robust reliability for cognitive measures involving memory and attention in 15-year-olds. Limitations related to assessing return-to-baseline after concussion in adolescents are discussed.

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