Search

A decrease in ghrelin plasma levels in morbidly obese patients subjected to bariatric surgery has been considered to help increase body weight loss. Contradictory results have been described after Roux-en-Y gastric bypass (RYGBP), and no study to date has compared RYGBP and vertical banded gastroplasty (VBG), the two main operations performed in the United States. We investigated the effects of RYGBP (10 patients) and VBG (12 patients) on basal and postmeal ghrelin plasma levels in 22 morbidly obese patients (20 F and 2 M), mean age 42.1 ± 3.7 years, mean weight 115 ± 3.9 kg, mean body mass index (BMI) 43.5 ± 1.7. Before surgery and after a 20% reduction in BMI, ghrelin concentrations (pg/mL; radioimmunoassay [RIA], DRG Diagnostics, Germany) were measured in all patients 45 min before and for 3 h after a standard liquid meal (Osmolite RTH solution, 500 mL, 504 kcal). The results were expressed as mean ± SD. Differences between times and groups were evaluated by Student's t-test and one-way analysis of variance (ANOVA). We found that basal ghrelin plasma levels were reduced after RYGBP (to 73.1 ± 6 pg/mL, p < .05) but increased after VBG (to 172 ± 26 pg/mL, p < .0009). After a standard liquid meal, ghrelin plasma levels decreased significantly over 1 h in VBG patients, whereas they remained unchanged in RYGBP patients. Since these results were obtained under the same metabolic and anthropometric conditions, we conclude that RYGBP acts through permanent inhibition of ghrelin secretion, whereas VBG merely restores the mechanisms of ghrelin regulation by nutrients. [ABSTRACT FROM AUTHOR]

Climate change is forecasted to drastically alter freshwater fish and mussel species distribution. Hydropower dam reservoirs, which modify downstream thermal regimes, may interact with climate change's impact on species distribution. This distribution shift may feedback, affecting hydropower operation costs through environmental compliance. We investigated how freshwater species distribution will shift due to climate change and hydropower reservoirs in the conterminous United States (CONUS), and how this will affect biodiversity mitigation costs for privately-owned hydropower plants. In general, using environmental niche modeling, we found that climate change increased the range of both freshwater fish and mussel species on average. For fish, this was mainly due to the expanded habitat for warm-water and cool-water fish species despite the diminish in habitat for cold-water species. Compared to climate change, thermal stratification of hydropower reservoirs had a small impact on the future range changes of these species in the tailwaters but showed an interaction with the effect of climate change on species range. Geographically, we projected an increase of species richness in the west and a decrease in the central and east of CONUS for fish, while projecting uniform increase for mussels. With this shift in species distribution, we estimated that the Northwest region will face the largest increase in mitigation cost, while the majority of plants in the Southeast will experience a decrease in cost., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)