172 research outputs found

    Adipogenesis in fetal pig subcutaneous adipose tissue: remarkable developmental features before the onset of adipogenesis

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    The collection of investigations indicating the importance of adipose tissue architecture to vasculogenesis and angiogenesis during adipogenesis is reviewed. Early in development of the architecture vascular structure develops before overt adipocyte differentiation. Adipocyte development and the expanding and elaborating vascularity are closely linked during adipocyte cluster growth. Furthermore, fetal adipose tissue studies show that location-dependent angiogenic potential ranges from more to less in regards to the extent of endothelial cells and developing arterioles present before overt adipogenesis. Fetal adipose tissue cells express and secrete numerous factors that may initiate the development of adipose tissue architecture and associated developmental gradients. Possibly, the neural connection between hypothalamic neurons and adipose tissue represents part of a regulatory pathway between the hypothalamus and adipose tissue development via neural driven patterns of blood vessel development. Finally, small blood vessels in fetal adipose tissue may phagocytose and metabolize circulating lipids in the absence of differentiated adipocytes. Therefore, several aspects of the stromal and vascular components of adipose tissue may play critical roles in the timing and distribution of developing adipose tissue.Adipobiology 2012; 4: 23-32

    Frames and Overflows in Rights Expression Languages

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    This paper analyzes the visions, schemas, and vocabularies of prominent rights expression languages, including Creative Commons, METS, ODRL, and MPEG-21. The paper extends Michel Callon's sociological insight that all forms of human agency are multiple and diverse. Callon argues, in the context of economic sociology, that one must constantly decide between a strategy emphasizing "framing" as the norm with "overflows" treated as leaks, or conversely a strategy accepting "overflows" as the norm with "framing" as inherently imperfect. Callon's categories are extended, through a modeling exercise, to the classification of current metadata schemes. The analysis suggests that metadata developers should explore what semantic choices and strictures are left out of metadata schemes, as well as those that are included. Such a thought exercise is especially useful in distinguishing areas suited for XML rights markup extensions

    Gene expression in hypothalamus, liver, and adipose tissues and food intake response to melanocortin-4 receptor agonist in pigs expressing melanocortin-4 receptor mutations

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    Transcriptional profiling was used to identify genes and pathways that responded to intracerebroventricular injection of melanocortin-4 receptor (MC4R) agonist [Nle4, D-Phe7]-α-melanocyte stimulating hormone (NDP-MSH) in pigs homozygous for the missense mutation in the MC4R, D298 allele (n = 12), N298 allele (n = 12), or heterozygous (n = 12). Food intake (FI) was measured at 12 and 24 h after treatment. All pigs were killed at 24 h after treatment, and hypothalamus, liver, and back-fat tissue was collected. NDP-MSH suppressed (P \u3c 0.004) FI at 12 and 24 h in all animals after treatment. In response to NDP-MSH, 278 genes in hypothalamus (q ≤ 0.07, P ≤ 0.001), 249 genes in liver (q ≤ 0.07, P ≤ 0.001), and 5,066 genes in fat (q ≤ 0.07, P ≤ 0.015) were differentially expressed. Pathway analysis of NDP-MSH-induced differentially expressed genes indicated that genes involved in cell communication, nucleotide metabolism, and signal transduction were prominently downregulated in the hypothalamus. In both liver and adipose tissue, energy-intensive biosynthetic and catabolic processes were downregulated in response to NDP-MSH. This included genes encoding for biosynthetic pathways such as steroid and lipid biosynthesis, fatty acid synthesis, and amino acid synthesis. Genes involved in direct energy-generating processes, such as oxidative phosphorylation, electron transport, and ATP synthesis, were upregulated, whereas TCA-associated genes were prominently downregulated in NDP-MSH-treated pigs. Our data also indicate a metabolic switch toward energy conservation since genes involved in energy-intensive biosynthetic and catabolic processes were downregulated in NDP-MSH-treated pigs

    Agricultural Biotechnology's Complementary Intellectual Assets

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    We formulate and test a hypothesis to explain the dramatic restructuring experienced recently by the plant breeding and seed industry. The reorganization can be explained in part by the desire to exploit complementarities between intellectual assets needed to create genetically modified organisms. This hypothesis is tested using data on agricultural biotechnology patents, notices for field tests of genetically modified organisms, and firm characteristics. The presence of complementarities is identified with a positive covariance in the unexplained variation of asset holdings. Results indicate that coordination of complementary assets have increased under the consolidation of the industry

    Neighborhood fast food restaurants and fast food consumption: A national study

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    <p>Abstract</p> <p>Background</p> <p>Recent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity.</p> <p>Methods</p> <p>We used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28) of the National Longitudinal Study of Adolescent Health (n = 13,150). Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics.</p> <p>Results</p> <p>In adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas.</p> <p>Conclusions</p> <p>Policies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research.</p

    Different Transcriptional Control of Metabolism and Extracellular Matrix in Visceral and Subcutaneous Fat of Obese and Rimonabant Treated Mice

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    BACKGROUND: The visceral (VAT) and subcutaneous (SCAT) adipose tissues play different roles in physiology and obesity. The molecular mechanisms underlying their expansion in obesity and following body weight reduction are poorly defined. METHODOLOGY: C57Bl/6 mice fed a high fat diet (HFD) for 6 months developed low, medium, or high body weight as compared to normal chow fed mice. Mice from each groups were then treated with the cannabinoid receptor 1 antagonist rimonabant or vehicle for 24 days to normalize their body weight. Transcriptomic data for visceral and subcutaneous adipose tissues from each group of mice were obtained and analyzed to identify: i) genes regulated by HFD irrespective of body weight, ii) genes whose expression correlated with body weight, iii) the biological processes activated in each tissue using gene set enrichment analysis (GSEA), iv) the transcriptional programs affected by rimonabant. PRINCIPAL FINDINGS: In VAT, "metabolic" genes encoding enzymes for lipid and steroid biosynthesis and glucose catabolism were down-regulated irrespective of body weight whereas "structure" genes controlling cell architecture and tissue remodeling had expression levels correlated with body weight. In SCAT, the identified "metabolic" and "structure" genes were mostly different from those identified in VAT and were regulated irrespective of body weight. GSEA indicated active adipogenesis in both tissues but a more prominent involvement of tissue stroma in VAT than in SCAT. Rimonabant treatment normalized most gene expression but further reduced oxidative phosphorylation gene expression in SCAT but not in VAT. CONCLUSION: VAT and SCAT show strikingly different gene expression programs in response to high fat diet and rimonabant treatment. Our results may lead to identification of therapeutic targets acting on specific fat depots to control obesity

    Explicitly searching for useful inventions: dynamic relatedness and the costs of connecting versus synthesizing

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    Inventions combine technological features. When features are barely related, burdensomely broad knowledge is required to identify the situations that they share. When features are overly related, burdensomely broad knowledge is required to identify the situations that distinguish them. Thus, according to my first hypothesis, when features are moderately related, the costs of connecting and costs of synthesizing are cumulatively minimized, and the most useful inventions emerge. I also hypothesize that continued experimentation with a specific set of features is likely to lead to the discovery of decreasingly useful inventions; the earlier-identified connections reflect the more common consumer situations. Covering data from all industries, the empirical analysis provides broad support for the first hypothesis. Regressions to test the second hypothesis are inconclusive when examining industry types individually. Yet, this study represents an exploratory investigation, and future research should test refined hypotheses with more sophisticated data, such as that found in literature-based discovery research
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