3,030 research outputs found

    MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings

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    Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up

    Six-dimensional Supergravity and Projective Superfields

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    We propose a superspace formulation of N=(1,0) conformal supergravity in six dimensions. The corresponding superspace constraints are invariant under super-Weyl transformations generated by a real scalar parameter. The known variant Weyl super-multiplet is recovered by coupling the geometry to a super-3-form tensor multiplet. Isotwistor variables are introduced and used to define projective superfields. We formulate a locally supersymmetric and super-Weyl invariant action principle in projective superspace. Some families of dynamical supergravity-matter systems are presented.Comment: 39 pages; v3: some modifications in section 2; equations (2.3), (2.14b), (2.16) and (2.17) correcte

    The effect of beta-alanine supplementation on neuromuscular fatigue in elderly (55–92 Years): a double-blind randomized study

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    <p>Abstract</p> <p>Background</p> <p>Ageing is associated with a significant reduction in skeletal muscle carnosine which has been linked with a reduction in the buffering capacity of muscle and in theory, may increase the rate of fatigue during exercise. Supplementing beta-alanine has been shown to significantly increase skeletal muscle carnosine. The purpose of this study, therefore, was to examine the effects of ninety days of beta-alanine supplementation on the physical working capacity at the fatigue threshold (PWC<sub>FT</sub>) in elderly men and women.</p> <p>Methods</p> <p>Using a double-blind placebo controlled design, twenty-six men (n = 9) and women (n = 17) (age ± SD = 72.8 ± 11.1 yrs) were randomly assigned to either beta-alanine (BA: 800 mg × 3 per day; n = 12; CarnoSyn™) or Placebo (PL; n = 14) group. Before (pre) and after (post) the supplementation period, participants performed a discontinuous cycle ergometry test to determine the PWC<sub>FT</sub>.</p> <p>Results</p> <p>Significant increases in PWC<sub>FT </sub>(28.6%) from pre- to post-supplementation were found for the BA treatment group (p < 0.05), but no change was observed with PL treatment. These findings suggest that ninety days of BA supplementation may increase physical working capacity by delaying the onset of neuromuscular fatigue in elderly men and women.</p> <p>Conclusion</p> <p>We suggest that BA supplementation, by improving intracellular pH control, improves muscle endurance in the elderly. This, we believe, could have importance in the prevention of falls, and the maintenance of health and independent living in elderly men and women.</p

    Subcellular heterogeneity of ryanodine receptor properties in ventricular myocytes with low T-tubule density

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    Rationale: In ventricular myocytes of large mammals, not all ryanodine receptor (RyR) clusters are associated with T-tubules (TTs); this fraction increases with cellular remodeling after myocardial infarction (MI). Objective: To characterize RyR functional properties in relation to TT proximity, at baseline and after MI. Methods: Myocytes were isolated from left ventricle of healthy pigs (CTRL) or from the area adjacent to a myocardial infarction (MI). Ca2+ transients were measured under whole-cell voltage clamp during confocal linescan imaging (fluo-3) and segmented according to proximity of TTs (sites of early Ca2+ release, F&gt;F50 within 20 ms) or their absence (delayed areas). Spontaneous Ca2+ release events during diastole, Ca2+ sparks, reflecting RyR activity and properties, were subsequently assigned to either category. Results: In CTRL, spark frequency was higher in proximity of TTs, but spark duration was significantly shorter. Block of Na+/Ca2+ exchanger (NCX) prolonged spark duration selectively near TTs, while block of Ca2+ influx via Ca2+ channels did not affect sparks properties. In MI, total spark mass was increased in line with higher SR Ca2+ content. Extremely long sparks (&gt;47.6 ms) occurred more frequently. The fraction of near-TT sparks was reduced; frequency increased mainly in delayed sites. Increased duration was seen in near-TT sparks only; Ca2+ removal by NCX at the membrane was significantly lower in MI. Conclusion: TT proximity modulates RyR cluster properties resulting in intracellular heterogeneity of diastolic spark activity. Remodeling in the area adjacent to MI differentially affects these RyR subpopulations. Reduction of the number of sparks near TTs and reduced local NCX removal limit cellular Ca2+ loss and raise SR Ca2+ content, but may promote Ca2+ waves

    Mutation screening and association study of RNASEL as a prostate cancer susceptibility gene

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    To date, germline mutations have been found in three candidate genes for hereditary prostate cancer: ELAC2 at 17p11, RNASEL at 1q25 and MSR1 at 8p22. RNASEL, encoding the 2′,5′-oligoadenylate-dependant RNase L, seems to have rare mutations in different ethnicities, such as M1I in Afro-Americans, E265X in men of European descent and 471delAAAG in Ashkenazi Jews. In order to evaluate the relevance of RNASEL in the German population, we sequenced its open reading frame to determine the spectrum and frequency of germline mutations. The screen included 303 affected men from 136 Caucasian families, of which 45 met the criteria for hereditary prostate cancer. Variants were analysed using a family-based association test, and genotyped in an additional 227 sporadic prostate cancer patients and 207 controls. We identified only two sib pairs (1.4% of our families) cosegregating conspicuous RNASEL variants with prostate cancer: the nonsense mutation E265X, and a new amino-acid substitution (R400P) of unknown functional relevance. Both alleles were also found at low frequencies (1.4 and 0.5%, respectively) in controls. No significant association of polymorphisms (I97L, R462Q and D541E) was observed, neither in case–control analyses nor by family-based association tests. In contrast to previous reports, our study does not suggest that common variants (i.e. R462Q) modify disease risk. Our results are not consistent with a high penetrance of deleterious RNASEL mutations. Due to the low frequency of germline mutations present in our sample, RNASEL does not have a significant impact on prostate cancer susceptibility in the German population

    Upper atmospheres and ionospheres of planets and satellites

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    The upper atmospheres of the planets and their satellites are more directly exposed to sunlight and solar wind particles than the surface or the deeper atmospheric layers. At the altitudes where the associated energy is deposited, the atmospheres may become ionized and are referred to as ionospheres. The details of the photon and particle interactions with the upper atmosphere depend strongly on whether the object has anintrinsic magnetic field that may channel the precipitating particles into the atmosphere or drive the atmospheric gas out to space. Important implications of these interactions include atmospheric loss over diverse timescales, photochemistry and the formation of aerosols, which affect the evolution, composition and remote sensing of the planets (satellites). The upper atmosphere connects the planet (satellite) bulk composition to the near-planet (-satellite) environment. Understanding the relevant physics and chemistry provides insight to the past and future conditions of these objects, which is critical for understanding their evolution. This chapter introduces the basic concepts of upper atmospheres and ionospheres in our solar system, and discusses aspects of their neutral and ion composition, wind dynamics and energy budget. This knowledge is key to putting in context the observations of upper atmospheres and haze on exoplanets, and to devise a theory that explains exoplanet demographics.Comment: Invited Revie

    Distinct physiological and behavioural functions for parental alleles of imprinted Grb10

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    Imprinted genes, defined by their preferential expression of a single parental allele, represent a subset of the mammalian genome and often have key roles in embryonic development1, but also postnatal functions including energy homeostasis2 and behaviour3, 4. When the two parental alleles are unequally represented within a social group (when there is sex bias in dispersal and/or variance in reproductive success)5, 6, imprinted genes may evolve to modulate social behaviour, although so far no such instance is known. Predominantly expressed from the maternal allele during embryogenesis, Grb10 encodes an intracellular adaptor protein that can interact with several receptor tyrosine kinases and downstream signalling molecules7. Here we demonstrate that within the brain Grb10 is expressed from the paternal allele from fetal life into adulthood and that ablation of this expression engenders increased social dominance specifically among other aspects of social behaviour, a finding supported by the observed increase in allogrooming by paternal Grb10-deficient animals. Grb10 is, therefore, the first example of an imprinted gene that regulates social behaviour. It is also currently alone in exhibiting imprinted expression from each of the parental alleles in a tissue-specific manner, as loss of the peripherally expressed maternal allele leads to significant fetal and placental overgrowth. Thus Grb10 is, so far, a unique imprinted gene, able to influence distinct physiological processes, fetal growth and adult behaviour, owing to actions of the two parental alleles in different tissues

    To respond or not to respond - a personal perspective of intestinal tolerance

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    For many years, the intestine was one of the poor relations of the immunology world, being a realm inhabited mostly by specialists and those interested in unusual phenomena. However, this has changed dramatically in recent years with the realization of how important the microbiota is in shaping immune function throughout the body, and almost every major immunology institution now includes the intestine as an area of interest. One of the most important aspects of the intestinal immune system is how it discriminates carefully between harmless and harmful antigens, in particular, its ability to generate active tolerance to materials such as commensal bacteria and food proteins. This phenomenon has been recognized for more than 100 years, and it is essential for preventing inflammatory disease in the intestine, but its basis remains enigmatic. Here, I discuss the progress that has been made in understanding oral tolerance during my 40 years in the field and highlight the topics that will be the focus of future research
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