58 research outputs found
Ramsey properties of finite measure algebras and topological dynamics of the group of measure preserving automorphisms: Some results and an open problem
We study in this paper ordered finite measure algebras from the point of view of Fraïssé and Ramsey theory. We also propose an open problem, which is a homogeneous version of the Dual Ramsey Theorem of Graham-Rothschild, and derive consequences of a positive answer to the study of the
topological dynamics of the automorphism group of a standard probability space and also the group of measure preserving homeomorphisms of the Cantor space
Topological partition relations to the form omega^*-> (Y)^1_2
Theorem: The topological partition relation omega^{*}-> (Y)^{1}_{2}
(a) fails for every space Y with |Y| >= 2^c ;
(b) holds for Y discrete if and only if |Y| <= c;
(c) holds for certain non-discrete P-spaces Y ;
(d) fails for Y= omega cup {p} with p in omega^{*} ;
(e) fails for Y infinite and countably compact
A convergence on Boolean algebras generalizing the convergence on the Aleksandrov cube
We compare the forcing related properties of a complete Boolean algebra B
with the properties of the convergences (the algebraic convergence)
and on B generalizing the convergence on the Cantor and
Aleksandrov cube respectively. In particular we show that is a
topological convergence iff forcing by B does not produce new reals and that
is weakly topological if B satisfies condition
(implied by the -cc). On the other hand, if is a
weakly topological convergence, then B is a -cc algebra or in
some generic extension the distributivity number of the ground model is greater
than or equal to the tower number of the extension. So, the statement "The
convergence on the collapsing algebra B=\ro
((\omega_2)^{<\omega}) is weakly topological" is independent of ZFC
A polychromatic Ramsey theory for ordinals
The Ramsey degree of an ordinal α is the least number n such that any colouring of the edges of the complete graph on α using finitely many colours contains an n-chromatic clique of order type α. The Ramsey degree exists for any ordinal α < ω ω . We provide an explicit expression for computing the Ramsey degree given α. We further establish a version of this result for automatic structures. In this version the ordinal and the colouring are presentable by finite automata and the clique is additionally required to be regular. The corresponding automatic Ramsey degree turns out to be greater than the set theoretic Ramsey degree. Finally, we demonstrate that a version for computable structures fails
MicroRNA-196a links human body fat distribution to adipose tissue extracellular matrix composition
Abstract
Background: Abdominal fat mass is associated with metabolic risk whilst gluteal femoral fat is paradoxically protective. MicroRNAs are known to be necessary for adipose tissue formation and function but their role in regulating human fat distribution remains largely unexplored.
Methods: An initial microarray screen of abdominal subcutaneous and gluteal adipose tissue, with validatory qPCR, identified microRNA-196a as being strongly differentially expressed between gluteal and abdominal subcutaneous adipose tissue.
Findings: We found that rs11614913, a SNP within pre-miR-196a-2 at the HOXC locus, is an eQTL for miR-196a expression in abdominal subcutaneous adipose tissue (ASAT). Observations in large cohorts showed that rs11614913 increased waist-to-hip ratio, which was driven specifically by an expansion in ASAT. In further experiments, rs11614913 was associated with adipocyte size. Functional studies and transcriptomic profiling of miR-196a knock-down pre-adipocytes revealed a role for miR-196a in regulating pre-adipocyte proliferation and extracellular matrix pathways.
Interpretation: These data identify a role for miR-196a in regulating human body fat distribution.: This work was supported by the Medical Research Council and Novo Nordisk UK Research Foundation (G1001959) and Swedish Research Council. We acknowledge the OBB-NIHR Oxford Biomedical Research Centre and the British Heart Foundation (BHF) (RG/17/1/32663). Work performed at the MRC Epidemiology Unit was funded by the United Kingdom's Medical Research Council through grants MC_UU_12015/1, MC_PC_13046, MC_PC_13048 and MR/L00002/1
Possible mediators of metabolic endotoxemia in women with obesity and women with obesity-diabetes in The Gambia.
AIMS/HYPOTHESIS: Translocation of bacterial debris from the gut causes metabolic endotoxemia (ME) that results in insulin resistance, and may be on the causal pathway to obesity-related type 2 diabetes. To guide interventions against ME we tested two hypothesised mechanisms for lipopolysaccharide (LPS) ingress: a leaky gut and chylomicron-associated transfer following a high-fat meal. METHODS: In lean women (n = 48; fat mass index (FMI) 9.6 kg/m2), women with obesity (n = 62; FMI 23.6 kg/m2) and women with obesity-diabetes (n = 38; FMI 24.9 kg/m2) we used the lactulose-mannitol dual-sugar permeability test (LM ratio) to assess gut integrity. Markers of ME (LPS, EndoCAb IgG and IgM, IL-6, CD14 and lipoprotein binding protein) were assessed at baseline, 2 h and 5 h after a standardised 49 g fat-containing mixed meal. mRNA expression of markers of inflammation, macrophage activation and lipid metabolism were measured in peri-umbilical adipose tissue (AT) biopsies. RESULTS: The LM ratio did not differ between groups. LPS levels were 57% higher in the obesity-diabetes group (P < 0.001), but, contrary to the chylomicron transfer hypothesis, levels significantly declined following the high-fat challenge. EndoCAb IgM was markedly lower in women with obesity and women with obesity-diabetes. mRNA levels of inflammatory markers in adipose tissue were consistent with the prior concept that fat soluble LPS in AT attracts and activates macrophages. CONCLUSIONS/INTERPRETATION: Raised levels of LPS and IL-6 in women with obesity-diabetes and evidence of macrophage activation in adipose tissue support the concept of metabolic endotoxemia-mediated inflammation, but we found no evidence for abnormal gut permeability or chylomicron-associated post-prandial translocation of LPS. Instead, the markedly lower EndoCAb IgM levels indicate a failure in sequestration and detoxification
Implantation of CPT1AM-expressing adipocytes reduces obesity and glucose intolerance in mice
Obesity and its associated metabolic comorbidities are a rising global health and social issue, with novel therapeutic approaches urgently needed. Adipose tissue plays a key role in the regulation of energy balance and adipose tissue-derived mesenchymal stem cells (AT-MSCs) have gained great interest in cell therapy. Carnitine palmitoyltransferase 1A (CPT1A) is the gatekeeper enzyme for mitochondrial fatty acid oxidation. Here, we aimed to generate adipocytes expressing a constitutively active CPT1A form (CPT1AM) that can improve the obese phenotype in mice after their implantation. AT-MSCs were differentiated into mature adipocytes, subjected to lentivirus-mediated expression of CPT1AM or the GFP control, and subcutaneously implanted into mice fed a high-fat diet (HFD). CPT1AM-implanted mice showed lower body weight, hepatic steatosis and serum insulin and cholesterol levels alongside improved glucose tolerance. HFD-induced increases in adipose tissue hypertrophy, fibrosis, inflammation, endoplasmic reticulum stress and apoptosis were reduced in CPT1AM-implanted mice. In addition, the expression of mitochondrial respiratory chain complexes was enhanced in the adipose tissue of CPT1AM-implanted mice. Our results demonstrate that implantation of CPT1AM-expressing AT-MSC-derived adipocytes into HFD-fed mice improves the obese metabolic phenotype, supporting the future clinical use of this ex vivo gene therapy approach
RSPO3 impacts body fat distribution and regulates adipose cell biology in vitro
Fat distribution is an independent cardiometabolic risk factor. However, its molecular and cellular underpinnings remain obscure. Here we demonstrate that two independent GWAS signals at RSPO3, which are associated with increased body mass index-adjusted waist-to-hip ratio, act to specifically increase RSPO3 expression in subcutaneous adipocytes. These variants are also associated with reduced lower-body fat, enlarged gluteal adipocytes and insulin resistance. Based on human cellular studies RSPO3 may limit gluteofemoral adipose tissue (AT) expansion by suppressing adipogenesis and increasing gluteal adipocyte susceptibility to apoptosis. RSPO3 may also promote upper-body fat distribution by stimulating abdominal adipose progenitor (AP) proliferation. The distinct biological responses elicited by RSPO3 in abdominal versus gluteal APs in vitro are associated with differential changes in WNT signalling. Zebrafish carrying a nonsense rspo3 mutation display altered fat distribution. Our study identifies RSPO3 as an important determinant of peripheral AT storage capacity
Re: Dutasteride in Localised Prostate Cancer Management: The REDEEM Randomised, Double-blind, Placebo-controlled Trial
Comment on "Dutasteride in localised prostate cancer management: the REDEEM randomised, double-blind, placebo-controlled trial. [Lancet. 2012]
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