78 research outputs found

    Helminth infection reactivates latent γ-herpesvirus via cytokine competition at a viral promoter

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    Mammals are coinfected by multiple pathogens that interact through unknown mechanisms. We found that helminth infection, characterized by the induction of the cytokine interleukin-4 (IL-4) and the activation of the transcription factor Stat6, reactivated murine γ-herpesvirus infection in vivo. IL-4 promoted viral replication and blocked the antiviral effects of interferon-γ (IFNγ) by inducing Stat6 binding to the promoter for an important viral transcriptional transactivator. IL-4 also reactivated human Kaposi's sarcoma-associated herpesvirus from latency in cultured cells. Exogenous IL-4 plus blockade of IFNγ reactivated latent murine γ-herpesvirus infection in vivo, suggesting a "two-signal" model for viral reactivation. Thus, chronic herpesvirus infection, a component of the mammalian virome, is regulated by the counterpoised actions of multiple cytokines on viral promoters that have evolved to sense host immune status

    Cowries in the archaeology of West Africa: the present picture

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    Despite the perceived importance of cowrie shells as indicators of long-distance connections in the West African past, their distribution and consumption patterns in archaeological contexts remain surprisingly underexplored, a gap that is only partly explicable by the sparse distribution of archaeological sites within the sub-continent. General writings on the timeline of importation of cowries into West Africa often fail to take into account the latest archaeological evidence and rely instead on accounts drawn from historical or ethnographic documents. This paper is based on a first-hand assessment of over 4500 shells from 78 sites across West Africa, examining chronology, shell species and processes of modification to assess what distribution patterns can tell us about the history of importation and usage of cowries. These first-hand analyses are paralleled by a consideration of published materials. We re-examine the default assumption that two distinct routes of entry existed — one overland from North Africa before the fifteenth century, another coming into use from the time sea links were established with the East African coast and becoming predominant by the middle of the nineteenth century. We focus on the eastern part of West Africa, where the importance of imported cowries to local communities in relatively recent periods is well known and from where we have a good archaeological sample. The conclusion is that on suitably large assemblages shell size can be an indication of provenance and that, while the present archaeological picture seems largely to confirm historical sources, much of this may be due to the discrepancy in archaeological data available from the Sahara/Sahel zone compared to the more forested regions of the sub-continent. Future archaeological work will clarify this matter

    A method for comparing multiple imputation techniques: A case study on the U.S. national COVID cohort collaborative

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    Healthcare datasets obtained from Electronic Health Records have proven to be extremely useful for assessing associations between patients’ predictors and outcomes of interest. However, these datasets often suffer from missing values in a high proportion of cases, whose removal may introduce severe bias. Several multiple imputation algorithms have been proposed to attempt to recover the missing information under an assumed missingness mechanism. Each algorithm presents strengths and weaknesses, and there is currently no consensus on which multiple imputation algorithm works best in a given scenario. Furthermore, the selection of each algorithm's parameters and data-related modeling choices are also both crucial and challenging. In this paper we propose a novel framework to numerically evaluate strategies for handling missing data in the context of statistical analysis, with a particular focus on multiple imputation techniques. We demonstrate the feasibility of our approach on a large cohort of type-2 diabetes patients provided by the National COVID Cohort Collaborative (N3C) Enclave, where we explored the influence of various patient characteristics on outcomes related to COVID-19. Our analysis included classic multiple imputation techniques as well as simple complete-case Inverse Probability Weighted models. Extensive experiments show that our approach can effectively highlight the most promising and performant missing-data handling strategy for our case study. Moreover, our methodology allowed a better understanding of the behavior of the different models and of how it changed as we modified their parameters. Our method is general and can be applied to different research fields and on datasets containing heterogeneous types

    Current assessment of the Red Rectangle band problem

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    In this paper we discuss our insights into several key problems in the identification of the Red Rectangle Bands (RRBs). We have combined three independent sets of observations in order to try to define the constraints guiding the bands. We provide a summary of the general behavior of the bands and review the evidence for a molecular origin of the bands. The extent, composition, and possible absorption effects of the bands are discussed. Comparison spectra of the strongest band obtained at three different spectral resolutions suggests that an intrinsic line width of individual rotational lines can be deduced. Spectroscopic models of several relatively simple molecules were examined in order to investigate where the current data are weak. Suggestions are made for future studies to enhance our understanding of these enigmatic bands

    Air-exposure behavior: a restricted or a common conduct among intertidal hermit crabs?

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    A new behavior related to shell care was recently reported for the intertidal hermit crab Clibanarius erythropus (Latreille, 1818) in the Gulf of Cádiz (southwestern Europe). It also has been observed in other species of the diogenid genera Clibanarius Dana, 1952, and Calcinus Dana, 1951, however, it has not been described as an active behavior. In the present study, intertidal hermit crabs from different species and localities were sampled to assess if air-exposure is a shell cleaning behavior restricted to some species of intertidal hermit crabs or if it is a more generalized behavior among species inhabiting intertidal habitats. The results revealed that air-exposure is an active behavior in species of Clibanarius and Calcinus, since we observed it also in Clibanarius albidigitus Nobili, 1901, and Calcinus obscurus Stimpson, 1859, from the Pacific coast of Costa Rica, although not in other intertidal species studied by us. We found interspecific differences in tolerance to physical stress of emerged hermit crabs. This air-exposure tolerance can be interpreted as a physiological adaptation to desiccation stress and is also related to the shell type they inhabit. Also, we provide additional features and details of the air-exposure behavior, combining observations of the first description in 2015 with our new field observations.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

    Cohort Profile: Pregnancy And Childhood Epigenetics (PACE) Consortium.

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    Development Psychopathology in context: famil

    Utilization of Different Aquaporin Water Channels in the Mouse Cervix During Pregnancy and Parturition and in Models of Preterm and Delayed Cervical Ripening Abbreviated Title: Aquaporin Water Channels in the Cervix

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    Abstract Biochemical changes of cervical connective tissue, including progressive disorganization of the collagen network and increased water content, occur during gestation to allow for cervical dilatation during labor, but the mechanisms that regulate cervical fluid balance are not fully understood. We examined whether aquaporins (AQPs), a family of membrane channel proteins that facilitate water transport, help mediate fluid balance in the mouse cervix during parturition. Of the thirteen known murine AQPs, AQP0-2, 6, 7, 9, 11 and 12 were absent or at the limits of detection. By Northern blot and real-time PCR, AQP3 expression was low in nongravid (NG) and mid-pregnancy cervices with peak expression on d19 and postpartum day 1 (PP1). AQP4 expression was generally low throughout pregnancy but showed a small upward trend at the time of parturition. AQP5 and AQP8 expression were significantly increased on d12-d15 but fell to NG/baseline by d19 and PP1. By in situ hybridization and immunohistochemistry, AQP3 was preferentially expressed in basal cell layers of the cervical epithelium whereas AQP4, 5, and 8 were primarily expressed in apical cell layers. Females with LPS-induced preterm labor had similar trends in AQP4, 5, and 8 expression to mice with natural labor at term gestation. Mice with delayed cervical remodeling due to deletion of the steroid 5α-reductase type 1 gene showed significant reduction in the levels of AQP3, 4, and 8 on d19 or PP1. Together, these studies suggest that AQPs 3, 4, 5, and 8 regulate distinct aspects of cervical water balance during pregnancy and parturition.

    High-resolution transrectal ultrasound: Pilot study of a novel technique for imaging clinically localized prostate cancer

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    Objectives: To detennine how high-resolution transrectal ultrasound (HiTRUS) compares with conventional TRUS (LoTRUS) for the visualization of prostate cancer. Methods and materials: Twenty-five men with known prostate cancer scheduled for radical prostatectomy were preoperatively imaged with both LoTRUS (5 MHz) and HiTRUS (21 MHz). Dynamic cine loops and still images for each modality were saved and subjected to blinded review by a radiologist looking for hypoechoic foci ≥5 mm in each sextant of the prostate. Following prostatectomy, areas of prostate cancer ≥5 mm on pathologic review were anatomically correlated to LoTRUS and HiTRUS findings. The accuracy of LoTRUS and HiTRUS to visualize prostate cancer in each sextant of the prostate and to identify high-grade and locally advanced disease was assessed. The McNemar test was used to compare sensitivity and specificity and paired dichotomous outcomes between imaging modalities. Results: Among 69 sextants with pathologically identified cancerous foci at radical prostatecomy, HiTRUS visualized 45 and missed 24, whereas LoTRUS visualized 26 and missed 43. Compared with LoTRUS, HiTRUS demonstrated improved sensitivity (65.2% vs. 37.7%) and specificity (71.6% vs. 65.4%). HiTRUS\u27s agreement with pathologic findings was twice as high as LoTRUS (P = 0.006). HiTRUS provided a nonsignificant increase in visualization of high-grade lesions (84% vs. 60%, P = 0.11). Conclusions: HiTRUS appears promising for prostate cancer imaging. Our initial experience suggests superiority to LoTRUS for the visualization of cancerous foci, and supports proceeding with a clinical trial in the biopsy setting
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