Removal of epididymal visceral adipose tissue prevents obesity-induced multi-organ insulin resistance in male mice

Obesity is associated with insulin resistance, an important risk factor of type 2 diabetes, atherogenic dyslipidemia, and nonalcoholic fatty liver disease. The major purpose of this study was to test hypothesize that prophylactic removal of epididymal visceral adipose tissue (VAT) prevents obesity-induced multi-organ (liver, skeletal muscle, adipose tissue) insulin resistance. Accordingly, we surgically removed epididymal VAT pads from adult C57BL/6J mice and evaluated in vivo and cellular metabolic pathways involved in glucose and lipid metabolism following chronic high-fat diet (HFD) feeding. We found that VAT removal decreases HFD-induced body weight gain while increasing subcutaneous adipose tissue (SAT) mass. Strikingly, VAT removal prevents obesity-induced insulin resistance and hyperinsulinemia and markedly enhances insulin-stimulated AKT-phosphorylation at serine-473 (Ser473) and threonine-308 (Thr308) sites in SAT, liver, and skeletal muscle. VAT removal leads to decreases in plasma lipid concentrations and hepatic triglyceride (TG) content. In addition, VAT removal increases circulating adiponectin, a key insulin-sensitizing adipokine, whereas it decreases circulating interleukin 6, a pro-inflammatory adipokine. Consistent with these findings, VAT removal increases adenosine monophosphate-activated protein kinase C phosphorylation, a major downstream target of adiponectin signaling. Data obtained from RNA sequencing suggest that VAT removal prevents obesity-induced oxidative stress and inflammation in liver and SAT, respectively. Taken together, these findings highlight the metabolic benefits and possible action mechanisms of prophylactic VAT removal on obesity-induced insulin resistance and hepatosteatosis. Our results also provide important insight into understanding the extraordinary capability of adipose tissue to influence whole-body glucose and lipid metabolism as an active endocrine organ

Effect of Progressive Weight Loss on Lactate Metabolism: A Randomized Controlled Trial.

OBJECTIVE:Lactate is an intermediate of glucose metabolism that has been implicated in the pathogenesis of insulin resistance. This study evaluated the relationship between glucose kinetics and plasma lactate concentration ([LAC]) before and after manipulating insulin sensitivity by progressive weight loss. METHODS:Forty people with obesity (BMI = 37.9 ± 4.3 kg/m2 ) were randomized to weight maintenance (n = 14) or weight loss (n = 19). Subjects were studied before and after 6 months of weight maintenance and before and after 5%, 11%, and 16% weight loss. A hyperinsulinemic-euglycemic clamp procedure in conjunction with [6,6-2 H2 ]glucose tracer infusion was used to assess glucose kinetics. RESULTS:At baseline, fasting [LAC] correlated positively with endogenous glucose production rate (r = 0.532; P = 0.001) and negatively with insulin sensitivity, assessed as the insulin-stimulated glucose disposal (r = -0.361; P = 0.04). Progressive (5% through 16%) weight loss caused a progressive decrease in fasting [LAC], and the decrease in fasting [LAC] after 5% weight loss was correlated with the decrease in endogenous glucose production (r = 0.654; P = 0.002) and the increase in insulin sensitivity (r = -0.595; P = 0.007). CONCLUSIONS:This study demonstrates the interrelationships among weight loss, hepatic and muscle glucose kinetics, insulin sensitivity, and [LAC], and it suggests that [LAC] can serve as an additional biomarker of glucose-related insulin resistance

Interfacial surface roughness determination by coherence scanning interferometry using noise compensation

The capability of coherence scanning interferometry has been extended recently to include the determination of the interfacial surface roughness between a thin film and a substrate when the surface perturbations are less than ∼10  nm∼10  nm in magnitude. The technique relies on introducing a first-order approximation to the helical complex field (HCF) function. This approximation of the HCF function enables a least-squares optimization to be carried out in every pixel of the scanned area to determine the heights of the substrate and/or the film layers in a multilayer stack. The method is fast but its implementation assumes that the noise variance in the frequency domain is statistically the same over the scanned area of the sample. This results in reconstructed surfaces that contain statistical fluctuations. In this paper we present an alternative least-squares optimization method, which takes into account the distribution of the noise variance-covariance in the frequency domain. The method is tested using results from a simulator and these show a significant improvement in the quality of the reconstructed surfaces

Reconstruction Algebras of Type D (I)

This is the second in a series of papers which give an explicit description of the reconstruction algebra as a quiver with relations; these algebras arise naturally as geometric generalizations of preprojective algebras of extended Dynkin diagrams. This paper deals with dihedral groups G=D_{n,q} for which all special CM modules have rank one, and we show that all but four of the relations on such a reconstruction algebra are given simply as the relations arising from a reconstruction algebra of type A. As a corollary, the reconstruction algebra reduces the problem of explicitly understanding the minimal resolution (=G-Hilb) to the same level of difficulty as the toric case.Comment: 31 pages, final versio

Multidimensional Nature of Molecular Organic Conductors Revealed by Angular Magnetoresistance Oscillations

Angle dependent magnetoresistance experiments on organic conductors exhibit a wide range of angular oscillations associated with the dimensionality and symmetry of the crystal structure and electron energy dispersion. In particular, characteristics associated with 1, 2, and 3 dimensional electronic motion are separately revealed when a sample is rotated through different crystal planes in a magnetic field. Originally discovered in the TMTSF based conductors, these effects are particularly pronounced in the related system (DMET)2I3. Here, experimental and computational results for magnetoresistance oscillations in this material, over a wide range of magnetic field orientations, are presented in such a manner as to uniquely highlight this multidimensional behavior.The calculations employ the Boltzmann transport equation that incorporates the systems triclinic crystal structure, which allows for accurate estimates of the transfer integrals along the crystallographic axes, verifying the 1d, 2d and 3d nature of (DMET)2I3, as well as crossovers between dimensions in the electronic behavior

Noncommutative resolutions using syzygies

Given a noether algebra with a noncommutative resolution, a general construction of new noncommutative resolutions is given. As an application, it is proved that any finite length module over a regular local or polynomial ring gives rise, via suitable syzygies, to a noncommutative resolution

Exact gauge invariant mass dependence of \alpha_s through two loops

A physically defined QCD coupling parameter naturally incorporates massive quark flavor thresholds in a gauge invariant, renormalization scale independent and analytical way. In this paper we summarize recent results for the finite-mass fermionic corrections to the heavy quark potential through two loops leading to the numerical solution of the physical and mass dependent Gell-Mann Low function. The decoupling-, massless- and Abelian-limits are reproduced and an analytical fitting function is obtained in the V-scheme. Thus the gauge invariant mass dependence of $\alpha_V$ is now known through two loops. Possible applications in lattice analyses, heavy quark physics and effective charges are briefly discussed.Comment: 5 pages, contribution to qcd99 in Montepellie

Refractive index determination by coherence scanning interferometry

Coherence scanning interferometry is established as a powerful noncontact, three-dimensional, metrology technique used to determine accurate surface roughness and topography measurements with subnanometer precision. The helical complex field (HCF) function is a topographically defined helix modulated by the electrical field reflectance, originally developed for the measurement of thin films. An approach to extend the capability of the HCF function to determine the spectral refractive index of a substrate or absorbing film has recently been proposed. In this paper, we confirm this new capability, demonstrating it on surfaces of silicon, gold, and a gold/ palladium alloy using silica and zirconia oxide thin films. These refractive index dispersion measurements show good agreement with those obtained by spectroscopic ellipsometr