Weight loss-induced stress in subcutaneous adipose tissue is related to weight regain

Initial successful weight loss is often followed by weight regain after the dietary intervention. Compared with lean people, cellular stress in adipose tissue is increased in obese subjects. However, the relation between cellular stress and the risk for weight regain after weight loss is unclear. Therefore, we determined the expression levels of stress proteins during weight loss and weight maintenance in relation to weight regain. In vivo findings were compared with results from in vitro cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. In total, eighteen healthy subjects underwent an 8-week diet programme with a 10-month follow-up. Participants were categorised as weight maintainers or weight regainers (WR) depending on their weight changes during the intervention. Abdominal subcutaneous adipose tissue biopsies were obtained before and after the diet and after the follow-up. In vitro differentiated SGBS adipocytes were starved for 96 h with low (0.55 mm) glucose. Levels of stress proteins were determined by Western blotting. WR showed increased expressions of beta-actin, calnexin, heat shock protein (HSP) 27, HSP60 and HSP70. Changes of beta-actin, HSP27 and HSP70 are linked to HSP60, a proposed key factor in weight regain after weight loss. SGBS adipocytes showed increased levels of beta-actin and HSP60 after 96 h of glucose restriction. The increased level of cellular stress proteins in the adipose tissue of WR probably resides in the adipocytes as shown by in vitro experiments. Cellular stress accumulated in adipose tissue during weight loss may be a risk factor for weight regain

Black hole uniqueness theorems and new thermodynamic identities in eleven dimensional supergravity

We consider stationary, non-extremal black holes in 11-dimensional supergravity having isometry group $\mathbb{R} \times U(1)^8$. We prove that such a black hole is uniquely specified by its angular momenta, its electric charges associated with the various 7-cycles in the manifold, together with certain moduli and vector valued winding numbers characterizing the topological nature of the spacetime and group action. We furthermore establish interesting, non-trivial, relations between the thermodynamic quantities associated with the black hole. These relations are shown to be a consequence of the hidden $E_{8(+8)}$ symmetry in this sector of the solution space, and are distinct from the usual "Smarr-type" formulas that can be derived from the first law of black hole mechanics. We also derive the "physical process" version of this first law applicable to a general stationary black hole spacetime without any symmetry assumptions other than stationarity, allowing in particular arbitrary horizon topologies. The work terms in the first law exhibit the topology of the horizon via the intersection numbers between cycles of various dimensions.Comment: 50pp, 3 figures, v2: references added, correction in appendix B, conclusions added, v3: reference section edited, typos removed, minor changes in appendix

The impact of tides on the capillary transition zone

The capillary transition zone, also known as the capillary fringe, is a zone where water saturations decrease with height above the water table/oil–water contact as a result of capillary action. In some oil reservoirs, this zone may contain a significant proportion of the oil in place. In groundwater assessments, the capillary fringe can profoundly affect contaminant transport. In this study, we investigated the influence of a tidally induced, semi-diurnal, change in water table depth on the water saturation distribution in the capillary fringe/transition zone. The investigation used a mixture of laboratory experiments, in which the change in saturation with depth was monitored over a period of 90 days, and numerical simulation. We show that tidal changes in water table depth can significantly alter the vertical water saturation profile from what would be predicted using capillary–gravity equilibrium and the drainage or imbibition capillary pressure curves

Real-time visualization of heterotrimeric G protein Gq activation in living cells

Contains fulltext : 97296.pdf (publisher's version ) (Open Access)BACKGROUND: Gq is a heterotrimeric G protein that plays an important role in numerous physiological processes. To delineate the molecular mechanisms and kinetics of signalling through this protein, its activation should be measurable in single living cells. Recently, fluorescence resonance energy transfer (FRET) sensors have been developed for this purpose. RESULTS: In this paper, we describe the development of an improved FRET-based Gq activity sensor that consists of a yellow fluorescent protein (YFP)-tagged Ggamma2 subunit and a Galphaq subunit with an inserted monomeric Turquoise (mTurquoise), the best cyan fluorescent protein variant currently available. This sensor enabled us to determine, for the first time, the kon (2/s) of Gq activation. In addition, we found that the guanine nucleotide exchange factor p63RhoGEF has a profound effect on the number of Gq proteins that become active upon stimulation of endogenous histamine H1 receptors. The sensor was also used to measure ligand-independent activation of the histamine H1 receptor (H1R) upon addition of a hypotonic stimulus. CONCLUSIONS: Our observations reveal that the application of a truncated mTurquoise as donor and a YFP-tagged Ggamma2 as acceptor in FRET-based Gq activity sensors substantially improves their dynamic range. This optimization enables the real-time single cell quantification of Gq signalling dynamics, the influence of accessory proteins and allows future drug screening applications by virtue of its sensitivity

Total energy expenditure is repeatable in adults but not associated with short-term changes in body composition

Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval: 1.9 ± 2.9 y) to assess repeatability of TEE, and to examine if TEE adjusted for age, sex, fat-free mass, and fat mass is associated with changes in weight or body composition. Here, we report that repeatability of TEE is high for adults, but not children. Bivariate Bayesian mixed models show no among or within-individual correlation between body composition (fat mass or percentage) and unadjusted TEE in adults. For adults aged 20-60 y (N = 267; time interval: 7.4 ± 12.2 weeks), increases in adjusted TEE are associated with weight gain but not with changes in body composition; results are similar for subjects with intervals >4 weeks (N = 53; 29.1 ± 12.8 weeks). This suggests low TEE is not a risk factor for, and high TEE is not protective against, weight or body fat gain over the time intervals tested

Variability in energy expenditure is much greater in males than females

In mammals, trait variation is often reported to be greater among males than females. However, to date, mainly only morphological traits have been studied. Energy expenditure represents the metabolic costs of multiple physical, physiological, and behavioral traits. Energy expenditure could exhibit particularly high greater male variation through a cumulative effect if those traits mostly exhibit greater male variation, or a lack of greater male variation if many of them do not. Sex differences in energy expenditure variation have been little explored. We analyzed a large database on energy expenditure in adult humans (1494 males and 3108 females) to investigate whether humans have evolved sex differences in the degree of interindividual variation in energy expenditure. We found that, even when statistically comparing males and females of the same age, height, and body composition, there is much more variation in total, activity, and basal energy expenditure among males. However, with aging, variation in total energy expenditure decreases, and because this happens more rapidly in males, the magnitude of greater male variation, though still large, is attenuated in older age groups. Considerably greater male variation in both total and activity energy expenditure could be explained by greater male variation in levels of daily activity. The considerably greater male variation in basal energy expenditure is remarkable and may be explained, at least in part, by greater male variation in the size of energy-demanding organs. If energy expenditure is a trait that is of indirect interest to females when choosing a sexual partner, this would suggest that energy expenditure is under sexual selection. However, we present a novel energetics model demonstrating that it is also possible that females have been under stabilizing selection pressure for an intermediate basal energy expenditure to maximize energy available for reproduction. (C) 2022 The Author(s). Published by Elsevier Ltd.Peer reviewe

Variability in energy expenditure is much greater in males than females

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Variation in human water turnover associated with environmental and lifestyle factors

Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using isotope-tracking (2H) methods. Age, body size, and composition were significantly associated with WT, as were physical activity, athletic status, pregnancy, socioeconomic status, and environmental characteristics (latitude, altitude, air temperature, and humidity). People who lived in countries with a low human development index (HDI) had higher WT than people in high-HDI countries. On the basis of this extensive dataset, we provide equations to predict human WT in relation to anthropometric, economic, and environmental factors.acceptedVersio