3,085 research outputs found
Suppression of mitochondrial respiration through recruitment of p160 myb binding protein to PGC-1α : modulation by p38 MAPK
The transcriptional coactivator PPAR gamma coactivator 1 α (PGC-1α) is a key regulator of metabolic processes such as mitochondrial biogenesis and respiration in muscle and gluconeogenesis in liver. Reduced levels of PGC-1α in humans have been associated with type II diabetes. PGC-1α contains a negative regulatory domain that attenuates its transcriptional activity. This negative regulation is removed by phosphorylation of PGC-1α by p38 MAPK, an important kinase downstream of cytokine signaling in muscle and β-adrenergic signaling in brown fat. We describe here the identification of p160 myb binding protein (p160MBP) as a repressor of PGC-1α. The binding and repression of PGC-1α by p160MBP is disrupted by p38 MAPK phosphorylation of PGC-1α. Adenoviral expression of p160MBP in myoblasts strongly reduces PGC-1α's ability to stimulate mitochondrial respiration and the expression of the genes of the electron transport system. This repression does not require removal of PGC-1α from chromatin, suggesting that p160MBP is or recruits a direct transcriptional suppressor. Overall, these data indicate that p160MBP is a powerful negative regulator of PGC-1α function and provide a molecular mechanism for the activation of PGC-1α by p38 MAPK. The discovery of p160MBP as a PGC-1α regulator has important implications for the understanding of energy balance and diabetes
Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity
Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by
alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var.
cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging
from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4).
All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show
differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl
esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3
also accepts a wide range of substrates but with very strong preference for producing benzyl acetate.
Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl
acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is
related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating
268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished
activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase
during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in
antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene
(1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the
multiplicity of AAT genes accounts for the great diversity of esters formed in melon
Alien Registration- St Pierre, Jen B. (Auburn, Androscoggin County)
https://digitalmaine.com/alien_docs/30337/thumbnail.jp
Role of Esrrg in the Fibrate-Mediated Regulation of Lipid Metabolism Genes in Human ApoA-I Transgenic Mice
We have used a new ApoA-I transgenic mouse model to identify by global gene expression profiling, candidate genes that affect lipid and lipoprotein metabolism in response to fenofibrate treatment. Multilevel bioinformatical analysis and stringent selection criteria (2-fold change, 0% false discovery rate) identified 267 significantly changed genes involved in several molecular pathways. The fenofibrate-treated group did not have significantly altered levels of hepatic human APOA-I mRNA and plasma ApoA-I compared with the control group. However, the treatment increased cholesterol levels to 1.95-fold mainly due to the increase in high-density lipoprotein (HDL) cholesterol. The observed changes in HDL are associated with the upregulation of genes involved in phospholipid biosynthesis and lipid hydrolysis, as well as phospholipid transfer protein. Significant upregulation was observed in genes involved in fatty acid transport and β-oxidation, but not in those of fatty acid and cholesterol biosynthesis, Krebs cycle and gluconeogenesis. Fenofibrate changed significantly the expression of seven transcription factors. The estrogen receptor-related gamma gene was upregulated 2.36-fold and had a significant positive correlation with genes of lipid and lipoprotein metabolism and mitochondrial functions, indicating an important role of this orphan receptor in mediating the fenofibrate-induced activation of a specific subset of its target genes.National Institutes of Health (HL48739 and HL68216); European Union (LSHM-CT-2006-0376331, LSHG-CT-2006-037277); the Biomedical Research Foundation of the Academy of Athens; the Hellenic Cardiological Society; the John F Kostopoulos Foundatio
Opportunities From the Digital Revolution: Implications for Researching, Publishing, and Consuming Qualitative Research
In the 1990s, the term 'online' research emerged as a new and vibrant suite of methods, focused on exploitation of sources not collected by traditional social science methods. Today, at least one part of the research life cycle is likely to be carried out 'online,' from data collection through to publishing. In this article, we seek to understand emergent modes of doing and reporting qualitative research 'online.' With a greater freedom now to term oneself a 'researcher,' what opportunities and problems do working with online data sources bring? We explore implications of emerging requirements to submit supporting data for social science journal articles and question whether these demands might disrupt the very nature of and identity of qualitative research. Finally, we examine more recent forms of publishing and communicating research that support outputs where data play an integral role in elucidating context and enhancing the reading experience
Calibration of myocardial T2 and T1 against iron concentration.
BACKGROUND: The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron.
METHODS: Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n=7) or cardiac transplantation (n=4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1=1/T1 and R2=1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy.
RESULTS: From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (± SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p<0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p<0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p<0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p<0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p<0.001).
CONCLUSION: Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive information to T2* for patients with myocardial siderosis. However, ex-vivo T1 measurements are less reliable due to the severe chemical effects of formalin on T1 shortening, and therefore T1 calibration may only be practical from in-vivo human studies
Place of death in patients with lung cancer: a retrospective cohort study from 2004-2013
Introduction: Many patients with cancer die in an acute hospital bed, which has been frequently identified as the least preferred location, with psychological and financial implications. This study looks at place and cause of death in patients with lung cancer and identifies which factors are associated with dying in an acute hospital bed versus at home.
Methods and Findings: We used the National Lung Cancer Audit linked to Hospital Episode Statistics and Office for National Statistics data to determine cause and place of death in those with lung cancer; both overall and by cancer Network. We used multivariate logistic regression to compare features of those who died in an acute hospital versus those who died at home.
Results: Of 143627 patients identified 40% (57678) died in an acute hospital, 29% (41957) died at home and 17% (24108) died in a hospice. Individual factors associated with death in an acute hospital bed compared to home were male sex, increasing age, poor performance status, social deprivation and diagnosis via an emergency route. There was marked variation between cancer Networks in place of death. The proportion of patients dying in an acute hospital ranged from 28% to 48%, with variation most notable in provision of hospice care (9% versus 33%). Cause of death in the majority was lung cancer (86%), with other malignancies, chronic obstructive pulmonary disease (COPD) and ischaemic heart disease (IHD) comprising 9% collectively.
Conclusions: A substantial proportion of patients with lung cancer die in acute hospital beds and this is more likely with increasing age, male sex, social deprivation and in those with poor performance status. There is marked variation between Networks, suggesting a need to improve end-of-life planning in those at greatest risk, and to review the allocation of resources to provide more hospice beds, enhanced community support and ensure equal access
Dioxin Toxicity In Vivo Results from an Increase in the Dioxin-Independent Transcriptional Activity of the Aryl Hydrocarbon Receptor
The Aryl hydrocarbon receptor (Ahr) is the nuclear receptor mediating the toxicity of dioxins -widespread and persistent pollutants whose toxic effects include tumor promotion, teratogenesis, wasting syndrome and chloracne. Elimination of Ahr in mice eliminates dioxin toxicity but also produces adverse effects, some seemingly unrelated to dioxin. Thus the relationship between the toxic and dioxin-independent functions of Ahr is not clear, which hampers understanding and treatment of dioxin toxicity. Here we develop a Drosophila model to show that dioxin actually increases the in vivo dioxin-independent activity of Ahr. This hyperactivation resembles the effects caused by an increase in the amount of its dimerisation partner Ahr nuclear translocator (Arnt) and entails an increased transcriptional potency of Ahr, in addition to the previously described effect on nuclear translocation. Thus the two apparently different functions of Ahr, dioxin-mediated and dioxin-independent, are in fact two different levels (hyperactivated and basal, respectively) of a single function
Gender-dependent differences in plasma matrix metalloproteinase-8 elevated in pulmonary tuberculosis.
Tuberculosis (TB) remains a global health pandemic and greater understanding of underlying pathogenesis is required to develop novel therapeutic and diagnostic approaches. Matrix metalloproteinases (MMPs) are emerging as key effectors of tissue destruction in TB but have not been comprehensively studied in plasma, nor have gender differences been investigated. We measured the plasma concentrations of MMPs in a carefully characterised, prospectively recruited clinical cohort of 380 individuals. The collagenases, MMP-1 and MMP-8, were elevated in plasma of patients with pulmonary TB relative to healthy controls, and MMP-7 (matrilysin) and MMP-9 (gelatinase B) were also increased. MMP-8 was TB-specific (p<0.001), not being elevated in symptomatic controls (symptoms suspicious of TB but active disease excluded). Plasma MMP-8 concentrations inversely correlated with body mass index. Plasma MMP-8 concentration was 1.51-fold higher in males than females with TB (p<0.05) and this difference was not due to greater disease severity in men. Gender-specific analysis of MMPs demonstrated consistent increase in MMP-1 and -8 in TB, but MMP-8 was a better discriminator for TB in men. Plasma collagenases are elevated in pulmonary TB and differ between men and women. Gender must be considered in investigation of TB immunopathology and development of novel diagnostic markers
Subjectivation and performative politics—Butler thinking Althusser and Foucault: intelligibility, agency and the raced-nationed-religioned subjects of education
Judith Butler is perhaps best known for her take-up of the debate between Derrida and Austin over the function of the performative and her subsequent suggestion that the subject be understood as performatively constituted. Another important but less often noted move within Butler‘s consideration of the processes through which the subject is constituted is her thinking between Althusser‘s notion of subjection and Foucault‘s notion of subjectivation. In this paper, I explore Butler‘s understanding of processes of subjectivation; examine the relationship between subjectivation and the performative suggested in and by Butler‘s work, and consider how the performative is implicated in processes of subjectivation – in =who‘ the subject is, or might be, subjectivated as. Finally, I examine the usefulness of understanding the subjectivating effects of discourse for education, in particular for educationalists concerned to make better sense of and interrupt educational inequalities. In doing this I offer a reading of an episode of ethnographic data generated in an Australian high School. I suggest that it is through subjectivating processes of the sort that Butler helps us to understand that some students are rendered subjects inside the educational endeavour, and others are rendered outside this endeavour or, indeed, outside student-hood
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