89 research outputs found

    Anoxia Tolerance During Vertebrate Development - Insights from Studies on the Annual Killifish Austrofundulus limnaeus

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    This is chapter 1 from Anoxia -- This book reviews how severe oxygen deprivation affects biological systems - from the molecular to the ecological level. The contributing authors come from diverse regions of the world, which proves the interest in the academic analysis of oxygen deprivation. The diversity in the experimental approach scientists take, in order to understand the influence oxygen deprivation has on living systems, is apparent throughout this book. One of the presented ideas deals with the exploration and examination of the physiological, cellular and genetic characteristics of killifish embryos and nematodes exposed to anoxia. Furthermore, the book includes material on the mechanisms regulating hypoxia and anoxia tolerance and their implications of on human health issues. Finally, new methodologies to examine oxygen deprivation and the impact of human-related activities on oxygen level, within important ecological systems such as Lake Victoria, are presented. There is no doubt that the oxygen molecule is central to every stratum of biological systems

    The hERG channel is dependent upon the Hsp90α isoform for maturation and trafficking

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    Heat shock protein 90 (Hsp90) has emerged as a promising therapeutic target for the treatment of cancer. Several Hsp90 inhibitors have entered clinical trials. However, some toxicological detriments have arisen, such as cardiotoxicity resulting from hERG inhibition following the administration of Hsp90 inhibitors. We sought to investigate this toxicity as hERG has been previously reported as a client protein that depends upon Hsp90 for its maturation and functional trafficking. In this study we show that hERG depends upon a single Hsp90 isoform. hERG preferentially co-immunoprecipitated with Hsp90α and genetic knockdown of Hsp90α, but not Hsp90β, resulted in a trafficking-defective hERG channel. This study demonstrates the importance of delineating the isoform dependence of Hsp90 client proteins and provides rationale for the design of isoform-selective Hsp90 inhibitors that avoid detrimental effect

    Early, transient depletion of plasmacytoid dendritic cells ameliorates autoimmunity in a lupus model

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    Plasmacytoid dendritic cells (pDCs) have long been implicated in the pathogenesis of lupus. However, this conclusion has been largely based on a correlative link between the copious production of IFN-α/β by pDCs and the IFN-α/β “signature” often seen in human lupus patients. The specific contribution of pDCs to disease in vivo has not been investigated in detail. For this reason, we generated a strain of BXSB lupus-prone mice in which pDCs can be selectively depleted in vivo. Early, transient ablation of pDCs before disease initiation resulted in reduced splenomegaly and lymphadenopathy, impaired expansion and activation of T and B cells, reduced antibodies against nuclear autoantigens and improved kidney pathology. Amelioration of pathology coincided with decreased transcription of IFN-α/β–induced genes in tissues. PDC depletion had an immediate impact on the activation of immune cells, and importantly, the beneficial effects on pathology were sustained even though pDCs later recovered, indicating an early pDC contribution to disease. Together, our findings demonstrate a critical function for pDCs during the IFN-α/β–dependent initiation of autoimmune lupus and point to pDCs as an attractive therapeutic target for the treatment of SLE

    A three-year longitudinal evaluation of the forearm bone density of users of etonogestrel- and levonorgestrel-releasing contraceptive implants

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to evaluate bone mineral density (BMD) at baseline and at 18 and 36 months of use of etonogestrel (ENG)-and levonorgestrel (LNG)-releasing contraceptive implants. This is a continuation of a previous study in which BMD was evaluated at baseline and at 18 months of use.</p> <p>Methods</p> <p>A total of 111 women, 19–43 years of age, wererandomly allocated to use one of the two implants. At 36 months of follow-up, only 36 and 39 women were still using the ENG- and LNG-releasing implants, respectively. BMD was evaluated at the distal and at the ultra-distal radius of the non-dominant forearm using dual-energy X-ray absorptiometry.</p> <p>Results</p> <p>There was no difference in the BMD of users of either implant at 18 and at 36 months. BMD was significantly lower at 18 and at 36 months at the distal radius in both groups of users compared to pre-insertion values; however, no difference was found at the ultra-distal radius.</p> <p>Conclusion</p> <p>Women 19–43 years of age using either one of these two contraceptive implants for 36 months had lower BMD values at the distal radius compared to pre-insertion values; however, no difference was found at the ultra-distal radius.</p

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    The Genome Length of Human Parainfluenza Virus Type 2 Follows the Rule of Six, and Recombinant Viruses Recovered from Non-Polyhexameric-Length Antigenomic cDNAs Contain a Biased Distribution of Correcting Mutations

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    Members of the Paramyxovirinae subfamily of the Paramyxoviridae family of viruses have the unusual requirement that the nucleotide length of the viral genome must be an even multiple of six in order for efficient RNA replication, and hence virus replication, to occur. Human parainfluenza virus type 2 (HPIV2) is the only member of the genus that has been reported to have a genome length that is not an even multiple of six, and it has also been recovered from a full-length antigenomic-sense cDNA that did not conform to the “rule of six.” To reexamine the issue of nucleotide length in natural isolates of HPIV2, a complete consensus genomic sequence was determined for three HPIV2 strains: Greer, Vanderbilt/1994 (V94), and Vanderbilt/1998. Each of these strains was found to have a genome length of 15,654 nucleotides (nt), thus conforming in each case to the rule of six. To directly examine the requirement that the genomic length of HPIV2 be an even multiple of six, we constructed six full-length antigenomic HPIV2/V94 cDNAs that deviated from a polyhexameric length by 0 to 5 nt. Recombinant HPIV2s were readily recovered from all of the cDNAs, including those that did not conform to the rule of six. One recombinant HPIV2 isolate was completely sequenced for each of the nonpolyhexameric antigenomic cDNAs. These were found to contain small nucleotide insertions or deletions that conferred polyhexameric length to the recovered genome. Interestingly, almost all of the length corrections occurred within the hemagglutinin-neuraminidase and large polymerase genes or the intervening intergenic region and thus were proximal to the insert that caused the deviation from the rule of six. These results demonstrate, in the context of complete infectious virus, that HPIV2 has a strong and seemingly absolute requirement for a polyhexameric genome
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