32 research outputs found

    Low serum transferrin levels in HFE C282Y homozygous subjects are associated with low CD8(+) T lymphocyte numbers.

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    Blood Cells Mol Dis. 2005 Nov-Dec;35(3):319-25. Epub 2005 Sep 1. Low serum transferrin levels in HFE C282Y homozygous subjects are associated with low CD8(+) T lymphocyte numbers. Macedo MF, Cruz E, Lacerda R, Porto G, de Sousa M. SourceDivision of Human Genetics and Genetic Disorders, Iron Genes and the Immune System Laboratory, Institute for Molecular and Cell Biology (IBMC), Oporto, Portugal. Abstract Hereditary hemochromatosis (HH) is a genetic iron overload disease, in the majority of cases associated with homozygosity for the C282Y mutation of the HFE gene. In spite of this genetic homogeneity, there is a great clinical heterogeneity among HH patients. Low CD8(+) lymphocyte numbers have been associated with a more severe expression of iron overload in HH patients, and in experimental models of iron overload. HH patients present low serum transferrin levels. Transferrin is an indispensable resource for lymphopoiesis. Lymphocyte homeostasis follows general ecology rules of population dynamics that involve competition for limiting resources. In the present study, we questioned whether transferrin levels could be associated with the anomalies seen previously in lymphocyte subset numbers in HH patients. Transferrin levels, total and subset T lymphocyte counts were done in 426 apparently healthy subjects genotyped for HFE. All HFE C282Y carriers presented significantly lower serum transferrin levels than the wild type group, a difference that could not be explained solely by the degree of iron overload. Significant differences were also seen in transferrin levels between males and females, with females presenting higher average serum Transferrin levels. In the population of subjects with Transferrin levels lower than 248 mg/dl, a positive correlation was seen between the peripheral CD8(+) lymphocyte numbers and serum transferrin levels (R(2) = 2.41; r = 0.16; P = 0.018). To test the possible limiting resource effect of transferrin, the correlation between transferrin levels and CD8(+) lymphocyte numbers was scrutinized in 34 HH patients, homozygous for the C282Y mutation. In the homozygous males, where the lowest average transferrin levels were seen, another highly significant correlation was observed between Transferrin levels and CD8(+) numbers. This correlation points to a possible role of transferrin as a limiting resource for MHC class I dependent lymphocyte proliferation, an effect that was not observed in C282Y homozygous female patients. PMID: 16140024 [PubMed - indexed for MEDLINE

    Control of CD1d-restricted antigen presentation and inflammation by sphingomyelin.

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    Invariant natural killer T (iNKT) cells recognize activating self and microbial lipids presented by CD1d. CD1d can also bind non-activating lipids, such as sphingomyelin. We hypothesized that these serve as endogenous regulators and investigated humans and mice deficient in acid sphingomyelinase (ASM), an enzyme that degrades sphingomyelin. We show that ASM absence in mice leads to diminished CD1d-restricted antigen presentation and iNKT cell selection in the thymus, resulting in decreased iNKT cell levels and resistance to iNKT cell-mediated inflammatory conditions. Defective antigen presentation and decreased iNKT cells are also observed in ASM-deficient humans with Niemann-Pick disease, and ASM activity in healthy humans correlates with iNKT cell phenotype. Pharmacological ASM administration facilitates antigen presentation and restores the levels of iNKT cells in ASM-deficient mice. Together, these results demonstrate that control of non-agonistic CD1d-associated lipids is critical for iNKT cell development and function in vivo and represents a tight link between cellular sphingolipid metabolism and immunity

    The ocean sampling day consortium

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    Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

    Nucleases as a barrier to gene silencing in the cotton boll weevil, Anthonomus grandis.

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    Made available in DSpace on 2018-01-04T23:23:41Z (GMT). No. of bitstreams: 1 journal.pone.0189600.pdf: 7131320 bytes, checksum: ece3da5d8a008843e58701868100618d (MD5) Previous issue date: 2018-01-04bitstream/item/170309/1/journal.pone.0189600.pd

    The Ocean Sampling Day Consortium

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    Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    CD1-Restricted T Cells at the Crossroad of Innate and Adaptive Immunity

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    Lipid-specific T cells comprise a group of T cells that recognize lipids bound to the MHC class I-like CD1 molecules. There are four isoforms of CD1 that are expressed at the surface of antigen presenting cells and therefore capable of presenting lipid antigens: CD1a, CD1b, CD1c, and CD1d. Each one of these isoforms has distinct structural features and cellular localizations, which promotes binding to a broad range of different types of lipids. Lipid antigens originate from either self-tissues or foreign sources, such as bacteria, fungus, or plants and their recognition by CD1-restricted T cells has important implications in infection but also in cancer and autoimmunity. In this review, we describe the characteristics of CD1 molecules and CD1-restricted lipid-specific T cells, highlighting the innate-like and adaptive-like features of different CD1-restricted T cell subtypes
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