649 research outputs found

    Nonspecific radiographic manifestations of cytomegalovirus infection in 4 HIV-positive adults – diagnosis through transbronchial biopsy

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    We report on 4 HIV-positive adult patients who presented (over a 2-year period) with clinically significant cytomegalovirus (CMV) pneumonia requiring transbronchial biopsy for diagnosis. The patients were not on antiretroviral therapy. Clinical findings were nonspecific, sputum samples were negative, blood test results were non-contributory, and empirical treatment had failed. Radiological findings were extensive but nonspecific. Three of the 4 patients were co-infected with Pneumocystis jirovecii (PJP) pneumonia, further confounding the radiological diagnosis

    Short communication: NKG2C+ NK cells contribute to increases in CD16+CD56- cells in HIV type 1+ individuals with high plasma viral load.

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    Chronic HIV-1 infection results in the expansion of both NKG2C+ and CD16+CD56- human natural killer cells. NKG2C+ cells proliferate in response to human cytomegalovirus (HCMV) and expansion of the dysfunctional CD56-CD16+ natural killer (NK) cells is associated with HIV-1 viremia. Here we report an association between increased proportions of CD56-CD16+ NK cells in viremic HIV-1+ individuals and an increased contribution of NKG2C+ cells to this subset. These data, in addition to anti-HCMV IgG serology, indicate a potential contribution of both HCMV and HIV-1 to NK cell dysfunction in HIV-1-infected individuals

    Methods of editing cloud and atmospheric layer affected pixels from satellite data

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    The location and migration of cloud, land and water features were examined in spectral space (reflective VIS vs. emissive IR). Daytime HCMM data showed two distinct types of cloud affected pixels in the south Texas test area. High altitude cirrus and/or cirrostratus and "subvisible cirrus" (SCi) reflected the same or only slightly more than land features. In the emissive band, the digital counts ranged from 1 to over 75 and overlapped land features. Pixels consisting of cumulus clouds, or of mixed cumulus and landscape, clustered in a different area of spectral space than the high altitude cloud pixels. Cumulus affected pixels were more reflective than land and water pixels. In August the high altitude clouds and SCi were more emissive than similar clouds were in July. Four-channel TIROS-N data were examined with the objective of developing a multispectral screening technique for removing SCi contaminated data

    Functional Significance of CD57 Expression on Human NK Cells and Relevance to Disease.

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    Historically, human NK cells have been identified as CD3(-)CD56(+)CD16(±) lymphocytes. More recently it has been established that CD57 expression defines functionally discrete sub-populations of NK cells. On T cells, CD57 expression has been regarded as a marker of terminal differentiation and (perhaps wrongly) of anergy and senescence. Similarly, CD57 expression seems to identify the final stages of peripheral NK cell maturation; its expression increases with age and is associated with chronic infections, particularly human cytomegalovirus infection. However, CD57(+) NK cells are highly cytotoxic and their presence seems to be beneficial in a number of non-communicable diseases. The purpose of this article is to review our current understanding of CD57 expression as a marker of NK cell function and disease prognosis, as well as to outline areas for further research

    Differentiation and adaptation of natural killer cells for anti-malarial immunity

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    Natural killer cells employ a diverse arsenal of effector mechanisms to target intracellular pathogens. Differentiation of natural killer (NK) cell activation pathways occurs along a continuum from reliance on innate pro-inflammatory cytokines and stress-induced host ligands through to interaction with signals derived from acquired immune responses. Importantly, the degree of functional differentiation of the NK cell lineage influences the magnitude and specificity of interactions with host cells infected with viruses, bacteria, fungi, and parasites. Individual humans possess a vast diversity of distinct NK cell clones, each with the capacity to vary along this functional differentiation pathway, which - when combined - results in unique individual responses to different infections. Here we summarize these NK cell differentiation events, review evidence for direct interaction of malaria-infected host cells with NK cells and assess how innate inflammatory signals induced by malaria parasite-associated molecular patterns influence the indirect activation and function of NK cells. Finally, we discuss evidence that anti-malarial immunity develops in parallel with advancing NK differentiation, coincident with a loss of reliance on inflammatory signals, and a refined capacity of NK cells to target malaria parasites more precisely, particularly through antibody-dependent mechanisms

    Quantifying fracture movement in a tibial fracture: surrogate model versus cadaver leg

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    Differential activation of CD57-defined natural killer cell subsets during recall responses to vaccine antigens

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    Natural killer (NK) cells contribute to the effector phase of vaccine-induced adaptive immune responses, secreting cytokines and releasing cytotoxic granules. The proportion of responding NK cells varies between individuals and by vaccine, suggesting that functionally discrete subsets of NK cells with different activation requirements may be involved. Here, we have used responses to individual components of the DTP vaccine [tetanus toxoid (TT), diphtheria toxoid (DT), whole cell inactivated pertussis] to characterize the NK cell subsets involved in interleukin-2-dependent recall responses. Culture with TT, DT or pertussis induced NK cell CD25 expression and interferon-γ production in previously vaccinated individuals. Responses were the most robust against whole cell pertussis, with responses to TT being particularly low. Functional analysis of discrete NK cell subsets revealed that transition from CD56bright to CD56dim correlated with increased responsiveness to CD16 cross-linking, whereas increasing CD57 expression correlated with a loss of responsiveness to cytokines. A higher frequency of CD56dim CD57− NK cells expressed CD25 and interferon-γ following stimulation with vaccine antigen compared with CD56dim CD57+ NK cells and made the largest overall contribution to this response. CD56dim CD57int NK cells represent an intermediate functional phenotype in response to vaccine-induced and receptor-mediated stimuli. These findings have implications for the ability of NK cells to contribute to the effector response after vaccination and for vaccine-induced immunity in older individuals

    Reducing the risk of ring breakage in taylor spatial frames: the effect of frame configuration on strain at the half ring junction

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    AIM: We have encountered four cases with Taylor spatial frames (TSF) (Smith & Nephew, Memphis, TN, USA) with breakage at the half-ring junction of the distal ring. This study examines the strain produced on different locations of the distal ring during loading and the effects on the strain of altering the frame construct. MATERIALS AND METHODS: We mounted two ring TSF constructs on tibia saw bone models. The proximal ring was the same in all constructs and consisted of a 2/3 180 mm ring attached with three wires. Construct 1 is reproducing the configuration of cases where failure was seen. The distal 155 mm ring is attached with three half pins. The half-ring junction is located in the midline. Construct 2 has a different half pin placement and an additional wire on the distal ring. Constructs 3 and 4 have the same half pin configuration to construct 1 but the distal ring is rotated 60° internally and externally, respectively. Strain gauges were attached to different locations and measurements recorded during loading. Statistical analysis was performed. RESULTS: Highest strain values were recorded at the half-ring junction of constructs 1 and 2 (>600 microstrains (με) in tension). Rotating the ring 60° internally significantly reduces the strain at the half-ring junction (<300 με) whilst external rotation by 60° further reduces the strain (<180 με). Ring strain is higher in areas close to half pin attachments. CONCLUSIONS: The highest strain is in the half-ring junction as the half rings are subjected to different loading modes. The thickness of the half-ring is halved and the second moment of area reduced further increasing breakage risk. Placing this junction close to the half pin–frame interface, as dictated by the anatomical safe zone further increases the strain. Rotating the distal ring 60° significantly reduces the strain at the half-ring junction. CLINICAL SIGNIFICANCE: Ring breakage is a rare but significant complication. This is the first study to address this potential mode of TSF failure. Insights and technical tips from this study can help reduce this

    The injured snowman

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    Total anomalous pulmonary venous return (TAPVR) is a rare congenital cardiac defect that may present with cyanosis, cardiac failure and failure to thrive in infancy. TAPVR type 1 has a typical radiographic appearance of the heart termed the snowman. We present a case of an infant with TAPVR type 1 with injuries in keeping with non-accidental injury (NAI) to highlight that children with chronic diseases are at greater risk of this kind of injury and that radiographic evaluation of the chest in cardiac disease plays a role beyond demonstrating the heart and vasculature of the chest

    Moiré interferometry applied to fracture in titanium tubes

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    Despite there being a substantial body of evidence to the contrary, moiré interferometry is often regarded - even by some adherents - as a curiosity of the optics lab. The present work seeks to demonstrate still further that the method can be an effective tool for practical materials research and assessment, in this case, in a novel and challenging experimental application involving fracture testing of heat exchanger tube material, the work being conducted in a conventional materials test laboratory setting. The key to the utility of the present setup lies with the priority given to its optical efficiency. In standard fracture toughness tests, it is axiomatic that standard specimen geometries be used. A dilemma arises when a material's properties are transformed to a substantial degree by the final stages of its process of manufacture, and when the very nature of the finished form dictates that standard geometries cannot be produced. The focus of this investigation was to measure crack-tip opening displacements (CTODs) in thin-walled titanium tubes. Fringe patterns corresponding to in-plane displacement contours were obtained interferometrically and the method for extracting CTODs from these is described. Significant differences in yield, ultimate strength, elongation, and fracture behaviour were observed for different material orientations
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