453 research outputs found

    Reversibility of lymphomas and lymphoproliferative lesions developing under cyclosporin-steroid therapy

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    Post-transplant lymphomas or other lymphoproliferative lesions, which were usually associated with Epstein-Barr virus infections, developed in 8, 4, 3, and 2 recipients, respectively, of cadaveric kidney, liver, heart, and heart-lung homografts. Reduction or discontinuance of immunosuppression caused regression of the lesions, often without subsequent rejection of the grafts. Chemotherapy and irradiation were not valuable. The findings may influence policies about treating other kinds of post-transplantation neoplasms

    Laser treatment in diabetic retinopathy

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    Diabetic retinopathy is a leading cause of visual impairment and blindness in developed countries due to macular edema and proliferative diabetic retinopathy (PDR). For both complications laser treatment may offer proven therapy: the Diabetic Retinopathy Study demonstrated that panretinal scatter photocoagulation reduces the risk of severe visual loss by >= 50% in eyes with high-risk characteristics. Pan-retinal scatter coagulation may also be beneficial in other PDR and severe nonproliferative diabetic retinopathy (NPDR) under certain conditions. For clinically significant macular edema the Early Treatment of Diabetic Retinopathy Study could show that immediate focal laser photocoagulation reduces the risk of moderate visual loss by at least 50%. When and how to perform laser treatment is described in detail, offering a proven treatment for many problems associated with diabetic retinopathy based on a high evidence level. Copyright (c) 2007 S. Karger AG, Basel

    Mercury sources to Lake Ozette and Lake Dickey : highly contaminated remote coastal lakes, Washington State, USA

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    Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Water, Air, & Soil Pollution 208 (2009): 275-286, doi:10.1007/s11270-009-0165-y.Mercury concentrations in largemouth bass and mercury accumulation rates in age-dated sediment cores were examined at Lake Ozette and Lake Dickey in Washington State. Goals of the study were to compare concentrations in fish tissues at the two lakes with lakes in a larger statewide dataset and evaluate factors influencing lake loading at Ozette and Dickey, which may include: catchment disturbances, coastal mercury cycling, and the role of trans-Pacific Asian mercury. Mercury fish tissue concentrations at the lakes were among the highest recorded in Washington State. Wet deposition and historical atmospheric monitoring from the area show no indication of enhanced deposition from Asian sources or coastal atmospheric processes. Sediment core records from the lakes displayed rapidly increasing sedimentation rates coinciding with commercial logging. The unusually high mercury flux rates and mercury tissue concentrations recorded at Lake Ozette and Lake Dickey appear to be associated with logging within the catchments

    An overview of the current status of CMB observations

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    In this paper we briefly review the current status of the Cosmic Microwave Background (CMB) observations, summarising the latest results obtained from CMB experiments, both in intensity and polarization, and the constraints imposed on the cosmological parameters. We also present a summary of current and future CMB experiments, with a special focus on the quest for the CMB B-mode polarization.Comment: Latest CMB results have been included. References added. To appear in "Highlights of Spanish Astrophysics V", Proceedings of the VIII Scientific Meeting of the Spanish Astronomical Society (SEA) held in Santander, 7-11 July, 200

    Socio-Economic Instability and the Scaling of Energy Use with Population Size

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    The size of the human population is relevant to the development of a sustainable world, yet the forces setting growth or declines in the human population are poorly understood. Generally, population growth rates depend on whether new individuals compete for the same energy (leading to Malthusian or density-dependent growth) or help to generate new energy (leading to exponential and super-exponential growth). It has been hypothesized that exponential and super-exponential growth in humans has resulted from carrying capacity, which is in part determined by energy availability, keeping pace with or exceeding the rate of population growth. We evaluated the relationship between energy use and population size for countries with long records of both and the world as a whole to assess whether energy yields are consistent with the idea of an increasing carrying capacity. We find that on average energy use has indeed kept pace with population size over long time periods. We also show, however, that the energy-population scaling exponent plummets during, and its temporal variability increases preceding, periods of social, political, technological, and environmental change. We suggest that efforts to increase the reliability of future energy yields may be essential for stabilizing both population growth and the global socio-economic system

    A simplified study of trans-mitral Doppler patterns

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    <p>Abstract</p> <p>Background</p> <p>Trans-mitral Doppler produces complex patterns with a great deal of variability. There are several confusing numerical measures and indices to study these patterns. However trans-mitral Doppler produces readymade data visualization by pattern generation which could be interpreted by pattern analysis. By following a systematic approach we could create an order and use this tool to study cardiac function.</p> <p>Presentation of the hypothesis</p> <p>In this new approach we eliminate the variables and apply pattern recognition as the main criterion of study. Proper terminologies are also devised to avoid confusion. In this way we can get some meaningful information.</p> <p>Testing the hypothesis</p> <p>Trans-mitral Doppler should be seen as patterns rather than the amplitude. The hypothesis can be proven by logical deduction, extrapolation and elimination of variables. Trans-mitral flow is also analyzed <it>vis-à-vis </it>the Starling's Law applied to the left atrium.</p> <p>Implications of the hypothesis</p> <p>Trans-mitral Doppler patterns are not just useful for evaluating diastolic function. They are also useful to evaluate systolic function. By following this schema we could get useful diagnostic information and therapeutic options using simple pattern recognition with minimal measurements. This simplified but practical approach will be useful in day to day clinical practice and help in understanding cardiac function better. This will also standardize research and improve communication.</p

    A review of elliptical and disc galaxy structure, and modern scaling laws

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    A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

    Big Genomes Facilitate the Comparative Identification of Regulatory Elements

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    The identification of regulatory sequences in animal genomes remains a significant challenge. Comparative genomic methods that use patterns of evolutionary conservation to identify non-coding sequences with regulatory function have yielded many new vertebrate enhancers. However, these methods have not contributed significantly to the identification of regulatory sequences in sequenced invertebrate taxa. We demonstrate here that this differential success, which is often attributed to fundamental differences in the nature of vertebrate and invertebrate regulatory sequences, is instead primarily a product of the relatively small size of sequenced invertebrate genomes. We sequenced and compared loci involved in early embryonic patterning from four species of true fruit flies (family Tephritidae) that have genomes four to six times larger than those of Drosophila melanogaster. Unlike in Drosophila, where virtually all non-coding DNA is highly conserved, blocks of conserved non-coding sequence in tephritids are flanked by large stretches of poorly conserved sequence, similar to what is observed in vertebrate genomes. We tested the activities of nine conserved non-coding sequences flanking the even-skipped gene of the teprhitid Ceratis capitata in transgenic D. melanogaster embryos, six of which drove patterns that recapitulate those of known D. melanogaster enhancers. In contrast, none of the three non-conserved tephritid non-coding sequences that we tested drove expression in D. melanogaster embryos. Based on the landscape of non-coding conservation in tephritids, and our initial success in using conservation in tephritids to identify D. melanogaster regulatory sequences, we suggest that comparison of tephritid genomes may provide a systematic means to annotate the non-coding portion of the D. melanogaster genome. We also propose that large genomes be given more consideration in the selection of species for comparative genomics projects, to provide increased power to detect functional non-coding DNAs and to provide a less biased view of the evolution and function of animal genomes

    Differences in HIV Natural History among African and Non-African Seroconverters in Europe and Seroconverters in Sub-Saharan Africa

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    Introduction It is unknown whether HIV treatment guidelines, based on resource-rich country cohorts, are applicable to African populations. Methods We estimated CD4 cell loss in ART-naïve, AIDS-free individuals using mixed models allowing for random intercept and slope, and time from seroconversion to clinical AIDS, death and antiretroviral therapy (ART) initiation by survival methods. Using CASCADE data from 20 European and 3 sub-Saharan African (SSA) cohorts of heterosexually-infected individuals, aged ≥15 years, infected ≥2000, we compared estimates between non-African Europeans, Africans in Europe, and Africans in SSA. Results Of 1,959 (913 non-Africans, 302 Europeans - African origin, 744 SSA), two-thirds were female; median age at seroconversion was 31 years. Individuals in SSA progressed faster to clinical AIDS but not to death or non-TB AIDS. They also initiated ART later than Europeans and at lower CD4 cell counts. In adjusted models, Africans (especially from Europe) had lower CD4 counts at seroconversion and slower CD4 decline than non-African Europeans. Median (95% CI) CD4 count at seroconversion for a 15–29 year old woman was 607 (588–627) (non-African European), 469 (442–497) (European - African origin) and 570 (551–589) (SSA) cells/µL with respective CD4 decline during the first 4 years of 259 (228–289), 155 (110–200), and 199 (174–224) cells/µL (p<0.01). Discussion Despite differences in CD4 cell count evolution, death and non-TB AIDS rates were similar across study groups. It is therefore prudent to apply current ART guidelines from resource-rich countries to African populations
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