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López Pérez C, Marchhart T, Kawashimo K, Nieto-Perez M, Parsons MS, Schamis H, Allain JP. A liquid metal dropper for experiments on the wettability of liquid metals on plasma facing components. Rev Sci Instrum 2023; 94:103506. [PMID: 37843418 DOI: 10.1063/5.0165646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
A liquid metal dropper has been developed as a part of the Ion-Gas-Neutral Interactions with Surfaces 2 (IGNIS-2) facility at The Pennsylvania State University. The dropper has the capability of directly applying drops to candidate plasma facing materials for nuclear fusion reactors to enable measurements of their liquid metal wetting properties. The results presented here are specific to the use of lithium in the dropper. This paper discusses the design choices of the liquid metal dropper and its chamber, including the heating and temperature control and the dropper's motorized operation. Lithium drops of masses ranging from 0.05 g up to 0.13 g, equivalent to drop diameters between 5.6 mm to 1 cm, have been consistently dispensed by the dropper. A new algorithm is developed and used to automate the analysis of the contact angle between the liquid drops and substrate material for efficient analysis of video data recorded to study the wetting properties of candidate plasma-facing components.
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Affiliation(s)
- C López Pérez
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - T Marchhart
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - K Kawashimo
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - M Nieto-Perez
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - M S Parsons
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - H Schamis
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - J P Allain
- Ken and Mary Alice Lindquist Department of Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Mallikarjun KS, Parsons MS, Nigogosyan Z, Goyal MS, Eldaya RW. Neuroimaging Findings in CHANTER Syndrome: A Case Series. AJNR Am J Neuroradiol 2022; 43:1136-1141. [PMID: 35798385 PMCID: PMC9575414 DOI: 10.3174/ajnr.a7569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/13/2022] [Indexed: 11/07/2022]
Abstract
Recently, a distinct clinicoradiologic entity involving cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) on MR imaging was identified. Patients present in an unresponsive state following exposure to drugs of abuse. Very little information exists regarding this entity, particularly in the radiology literature. We identify and describe 3 patients at our institution with similar clinical and radiographic findings. Multifocal restricted diffusion in the brain is typically associated with poor outcomes. By contrast, CHANTER involves intraventricular obstructive hydrocephalus that, when treated, can lead to substantial recovery. This novel syndrome should be on the differential in patients who present in an unresponsive state after recent opioid use in the context of the above imaging findings. Additional diagnoses on the differential can include ischemic stroke, hypoxic-ischemic encephalopathy, "chasing the dragon," leukoencephalopathy, opioid-associated amnestic syndrome, and pediatric opioid-use-associated neurotoxicity with cerebellar edema.
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Affiliation(s)
- K S Mallikarjun
- From the Mallinckrodt Institute of Radiology (K.S.M., M.S.P., Z.N., M.S.G., R.W.E.), Washington University School of Medicine, Ringgold Standard Institution, St. Louis, Missouri
| | - M S Parsons
- From the Mallinckrodt Institute of Radiology (K.S.M., M.S.P., Z.N., M.S.G., R.W.E.), Washington University School of Medicine, Ringgold Standard Institution, St. Louis, Missouri
| | - Z Nigogosyan
- From the Mallinckrodt Institute of Radiology (K.S.M., M.S.P., Z.N., M.S.G., R.W.E.), Washington University School of Medicine, Ringgold Standard Institution, St. Louis, Missouri
| | - M S Goyal
- From the Mallinckrodt Institute of Radiology (K.S.M., M.S.P., Z.N., M.S.G., R.W.E.), Washington University School of Medicine, Ringgold Standard Institution, St. Louis, Missouri
| | - R W Eldaya
- From the Mallinckrodt Institute of Radiology (K.S.M., M.S.P., Z.N., M.S.G., R.W.E.), Washington University School of Medicine, Ringgold Standard Institution, St. Louis, Missouri.,MD Anderson Cancer Center, Diagnostic Imaging Division (R.W.E.), Houston, Texas
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Schroeder A, Van Stavern G, Orlowski HLP, Stunkel L, Parsons MS, Rhea L, Sharma A. Detection of Optic Neuritis on Routine Brain MRI without and with the Assistance of an Image Postprocessing Algorithm. AJNR Am J Neuroradiol 2021; 42:1130-1135. [PMID: 33737263 DOI: 10.3174/ajnr.a7068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 12/20/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE At times, there is a clinical need for using routine brain MR imaging performed close to the time of onset of patients' visual symptoms to firmly establish the diagnosis of optic neuritis. Our aim was to assess the diagnostic performance of radiologists in detecting optic neuritis on routine brain MR images and whether this performance could be enhanced using a postprocessing algorithm. MATERIALS AND METHODS In this retrospective case-control study of 60 patients (37 women, 23 men; mean age, 47.2 [SD, 17.9] years), 2 blinded neuroradiologists evaluated T2-weighted FLAIR and contrast-enhanced T1WI from brain MR imaging for the presence of imaging evidence of optic neuritis. Images were processed using an image-processing algorithm that aimed to selectively accentuate the signal intensity of diseased optic nerves. We assessed the effect of image processing on the contrast-to-noise ratio between the optic nerves and normal-appearing white matter and on the diagnostic performance of the neuroradiologists, including the interobserver reliability. RESULTS The average sensitivity of readers was 55%, 56.5%, and 30.0% on FLAIR, coronal contrast-enhanced T1WI, and axial contrast-enhanced T1WI, respectively. Sensitivities were lower in the absence of fat saturation on FLAIR (P = .001) and coronal contrast-enhanced T1WI (P = .04). Processing increased the contrast-to-noise ratio of diseased (P value range = .03 to <.001) but not of control optic nerves. Processing did not improve the sensitivity but improved the specificity and positive predictive value. Interobserver agreement improved from slight to good. CONCLUSIONS Detection of optic neuritis on routine brain MR imaging is challenging. Specificity, positive predictive value, and interobserver agreement can be improved by postprocessing of MR images.
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Affiliation(s)
- A Schroeder
- Washington University in Saint Louis School of Medicine, (A. Schroeder), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - G Van Stavern
- Departments of Ophthalmology and Visual Sciences (G.V.S., L.S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri.,Department of Neurology (G.V.S., L.S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - H L P Orlowski
- Mallinckrodt Institute of Radiology (H.L.P.O., M.S.P., A. S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - L Stunkel
- Departments of Ophthalmology and Visual Sciences (G.V.S., L.S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri.,Department of Neurology (G.V.S., L.S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - M S Parsons
- Mallinckrodt Institute of Radiology (H.L.P.O., M.S.P., A. S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - L Rhea
- Department of Biostatistics (L.R.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri
| | - A Sharma
- Mallinckrodt Institute of Radiology (H.L.P.O., M.S.P., A. S.), Washington University in Saint Louis School of Medicine, St. Louis, Missouri.
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Stunkel L, Sharma A, Parsons MS, Salter A, Van Stavern GP. Evaluating the Utility of a Postprocessing Algorithm for MRI Evaluation of Optic Neuritis. AJNR Am J Neuroradiol 2019; 40:1043-1048. [PMID: 31048299 DOI: 10.3174/ajnr.a6057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/31/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE MR imaging is useful for the detection and/or confirmation of optic neuritis. The objective of this study was to determine whether a postprocessing algorithm selectively increases the contrast-to-noise ratio of abnormal optic nerves in optic neuritis, facilitating this diagnosis on MR imaging. MATERIALS AND METHODS In this retrospective case-control study, coronal FLAIR images and coronal contrast-enhanced T1WI from 44 patients (31 eyes with clinically confirmed optic neuritis and 28 control eyes) underwent processing using a proprietary postprocessing algorithm designed to detect and visually highlight regions of contiguous increases in signal intensity by increasing the signal intensities of regions that exceed a predetermined threshold. For quantitative evaluation of the effect on image processing, the contrast-to-noise ratio of equivalent ROIs and the contrast-to-noise ratio between optic nerves and normal-appearing white matter were measured on baseline and processed images. The effect of image-processing on diagnostic performance was evaluated by masked reviews of baseline and processed images by 6 readers with varying experience levels. RESULTS In abnormal nerves, processing resulted in an increase in the median contrast-to-noise ratio from 17.8 to 85.0 (P < .001) on FLAIR and from 19.4 to 93.7 (P < .001) on contrast-enhanced images. The contrast-to-noise ratio for control optic nerves was not affected by processing (P = 0.13). Image processing had a beneficial effect on radiologists' diagnostic performance, with an improvement in sensitivities for 5/6 readers and relatively unchanged specificities. Interobserver agreement improved following processing. CONCLUSIONS Processing resulted in a selective increase in the contrast-to-noise ratio for diseased nerves and corresponding improvement in the detection of optic neuritis on MR imaging by radiologists.
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Affiliation(s)
- L Stunkel
- From the Department of Neurology (L.S.)
| | - A Sharma
- Mallinckrodt Institute of Radiology (A. Sharma, M.S.P.)
| | - M S Parsons
- Mallinckrodt Institute of Radiology (A. Sharma, M.S.P.)
| | - A Salter
- Division of Biostatistics (A. Salter)
| | - G P Van Stavern
- Department of Ophthalmology and Visual Sciences (G.P.V.S.), Washington University in St. Louis School of Medicine, St. Louis, Missouri.
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Dahi F, Parsons MS, Orlowski HLP, Salter A, Dahiya S, Sharma A. Image Processing to Improve Detection of Mesial Temporal Sclerosis in Adults. AJNR Am J Neuroradiol 2019; 40:798-801. [PMID: 30948379 DOI: 10.3174/ajnr.a6022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/18/2019] [Indexed: 11/07/2022]
Abstract
In this retrospective case-control study, we investigated whether an image-processing algorithm designed to exaggerate the intensity of diseased hippocampi on FLAIR images can improve the diagnostic accuracy and interobserver reliability of radiologists in detecting mesial temporal sclerosis-related hippocampal signal alteration. Herein, we share the results of this study that showed that the image processing improved the confidence of radiologists in detecting mesial temporal sclerosis-related signal alteration, allowing an improved sensitivity, specificity, and interobserver reliability.
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Affiliation(s)
- F Dahi
- From the Progressive Physicians Association (F.D), Bethlehem, Pennsylvania
| | - M S Parsons
- Mallinckrodt Institute of Radiology (M.S.P., H.L.P.O., A.Sharma)
| | - H L P Orlowski
- Mallinckrodt Institute of Radiology (M.S.P., H.L.P.O., A.Sharma)
| | - A Salter
- Department of Biostatistics (A.Salter)
| | - S Dahiya
- Department of Pathology and Immunology (S.D.), Washington University School of Medicine, Washington University in St Louis, St Louis, Missouri
| | - A Sharma
- Mallinckrodt Institute of Radiology (M.S.P., H.L.P.O., A.Sharma)
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Gooneratne SL, Center RJ, Kent SJ, Parsons MS. Functional advantage of educated KIR2DL1(+) natural killer cells for anti-HIV-1 antibody-dependent activation. Clin Exp Immunol 2016; 184:101-9. [PMID: 26647083 DOI: 10.1111/cei.12752] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/13/2015] [Accepted: 11/25/2015] [Indexed: 11/28/2022] Open
Abstract
Evidence from the RV144 HIV-1 vaccine trial implicates anti-HIV-1 antibody-dependent cellular cytotoxicity (ADCC) in vaccine-conferred protection from infection. Among effector cells that mediate ADCC are natural killer (NK) cells. The ability of NK cells to be activated in an antibody-dependent manner is reliant upon several factors. In general, NK cell-mediated antibody-dependent activation is most robust in terminally differentiated CD57(+) NK cells, as well as NK cells educated through ontological interactions between inhibitory killer immunoglobulin-like receptors (KIR) and their major histocompatibility complex class I [MHC-I or human leucocyte antigen (HLA-I)] ligands. With regard to anti-HIV-1 antibody-dependent NK cell activation, previous research has demonstrated that the epidemiologically relevant KIR3DL1/HLA-Bw4 receptor/ligand combination confers enhanced activation potential. In the present study we assessed the ability of the KIR2DL1/HLA-C2 receptor/ligand combination to confer enhanced activation upon direct stimulation with HLA-I-devoid target cells or antibody-dependent stimulation with HIV-1 gp140-pulsed CEM.NKr-CCR5 target cells in the presence of an anti-HIV-1 antibody source. Among donors carrying the HLA-C2 ligand for KIR2DL1, higher interferon (IFN)-γ production was observed within KIR2DL1(+) NK cells than in KIR2DL1(-) NK cells upon both direct and antibody-dependent stimulation. No differences in KIR2DL1(+) and KIR2DL1(-) NK cell activation were observed in HLA-C1 homozygous donors. Additionally, higher activation in KIR2DL1(+) than KIR2DL1(-) NK cells from HLA-C2 carrying donors was observed within less differentiated CD57(-) NK cells, demonstrating that the observed differences were due to education and not an overabundance of KIR2DL1(+) NK cells within differentiated CD57(+) NK cells. These observations are relevant for understanding the regulation of anti-HIV-1 antibody-dependent NK cell responses.
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Affiliation(s)
- S L Gooneratne
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - R J Center
- Centre for Biomedical Research, Burnet Institute, Melbourne, VIC, Australia
| | - S J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia.,Melbourne Sexual Health Centre, Carlton, VIC, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne, Melbourne, VIC, Australia
| | - M S Parsons
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
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Tang CC, Isitman G, Bruneau J, Tremblay C, Bernard NF, Kent SJ, Parsons MS. Phenotypical and functional profiles of natural killer cells exhibiting matrix metalloproteinase-mediated CD16 cleavage after anti-HIV antibody-dependent activation. Clin Exp Immunol 2015; 181:275-85. [PMID: 25644502 DOI: 10.1111/cei.12593] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 01/08/2015] [Accepted: 01/14/2015] [Indexed: 01/01/2023] Open
Abstract
Natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC) has been linked to protection from HIV infection and slower progression towards AIDS. However, antibody-dependent activation of NK cells results in phenotypical alterations similar to those observed on NK cells from individuals with progressive HIV infection. Activation of NK cells induces matrix metalloproteinase (MMP)-mediated cleavage of cell surface CD16. In the present study we assessed the phenotype and functional profile of NK cells exhibiting post-activation MMP-mediated CD16 cleavage. We found that NK cells achieving the highest levels of activation during stimulation exhibit the most profound decreases in CD16 expression. Further, we observed that educated KIR3DL1(+) NK cells from human leucocyte antigen (HLA)-Bw4-carrying donors exhibit larger decreases in CD16 expression post-activation than the KIR3DL1(-) NK cell subset containing cells educated via other inhibitory receptor/ligand combinations and non-educated NK cells. Lastly, we assessed the ex-vivo expression of CD16 on educated KIR3DL1(+) NK cells and the KIR3DL1(-) NK cell subset from HLA-Bw4-carrying HIV-uninfected and HIV-infected donors. Suggestive of in-vivo activation of KIR3DL1(+) NK cells during HIV infection, CD16 expression was higher on KIR3DL1(+) than KIR3DL1(-) NK cells in uninfected donors but similar on both subsets in HIV-infected donors. These results are discussed in the context of how they may assist with understanding HIV disease progression and the design of immunotherapies that utilize antibody-dependent NK cell responses.
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Affiliation(s)
- C-C Tang
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute, Melbourne, Victoria, Australia
| | - G Isitman
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - J Bruneau
- Centre de Recherche du Centre Hospitalier de l'Universite de Montreal (CRCHUM), Montreal, Quebec, Canada
| | - C Tremblay
- Centre de Recherche du Centre Hospitalier de l'Universite de Montreal (CRCHUM), Montreal, Quebec, Canada
| | - N F Bernard
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - S J Kent
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute, Melbourne, Victoria, Australia.,Melbourne Sexual Health Centre, Carlton, Victoria, Australia
| | - M S Parsons
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute, Melbourne, Victoria, Australia
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Parsons MS, Zanoni P, Tallon B, Miconiatis S, Shoukry N, Bruneau J, Tsoukas CM, Bernard NF. KIR/HLA genotype combinations are determinants of Natural Killer (NK) cell mediated antibody-dependent cellular cytotoxicity (ADCC) potency. Retrovirology 2012. [PMCID: PMC3441962 DOI: 10.1186/1742-4690-9-s2-p187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Sharma A, Parsons MS, Pilgram TK. Temporal association of annular tears and nuclear degeneration: lessons from the pediatric population. AJNR Am J Neuroradiol 2009; 30:1541-5. [PMID: 19461059 DOI: 10.3174/ajnr.a1625] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Studies done mainly in adults have shown an association between annular tears and nuclear degeneration. We wanted to study this association in the pediatric population to better understand the natural history of disk degeneration in its early stages. We hypothesized that this association is discernible even at a young age and that annular tears precede nuclear degeneration. MATERIALS AND METHODS Twenty-six children with back pain and known disk pathology were identified from our radiology report data base. Two neuroradiologists independently evaluated T12 through S1 intervertebral disks in these images. One reader evaluated the disks for the presence and type of annular tears. The other reader graded the signal intensity of the disks on an ordinal scale and the extent of disk degeneration on the Pfirrmann scale. Mean degeneration and signal-intensity grades were compared for disks with radial tears, disks with nonradial tears, and disks without annular tears. RESULTS Fifty-six disks had radial tears. These demonstrated significantly higher nuclear degeneration grades and greater signal-intensity loss than disks with nonradial tears or disks with no annular tears. About one third (30.3%) of the disks with radial tears had a normal nuclear signal intensity. Only 3% of disks with a signal-intensity grade of >/=3 had an intact annulus. CONCLUSIONS Nuclear degeneration in children is associated with radial annular tears and rarely occurs in the absence of annular tears.
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Affiliation(s)
- A Sharma
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd., St. Louis, MO 63110, USA.
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Abstract
Maintaining health requires a dynamic balance between the influence of pro-inflammatory and anti-inflammatory mediators. While inflammation serves an important protective role against infection, unrestrained inflammation is acutely lethal and unresolved inflammation contributes to a broad range of chronic disorders. Immunotherapy with cytokines themselves or cytokine antagonists faces strict limitations due to efficacy, safety and cost. More successful treatment of the pro-inflammatory component of chronic disorders may emerge from strategies designed to reset the balance between pro and anti-inflammatory cytokines through physiological regulatory pathways. One emerging avenue for this approach is exploitation of the link between the cell surface protein CD36 and the anti-inflammatory cytokine interleukin-10 (IL-10). Agents that increase CD36 expression and agents that directly bind to CD36 have anti-inflammatory properties that may directly relate to induction of IL-10. The immunosuppressive effects of apoptotic cells were first reported more than a decade ago and have since been tested in animal models and several clinical trials. A recent publication demonstrates that induction of IL-10 by apoptotic cells is largely dependent upon the interaction between apoptotic cells and CD36, the receptor on monocytes and macrophages for apoptotic cells. This provides a direct mechanistic link between CD36 engagement and IL-10 induction, opening up new possibilities for using CD36 ligands, agents that increase CD36 expression or a combination of both to modulate inflammation and treat, or even prevent, an important set of chronic disorders.
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Affiliation(s)
- M S Parsons
- Immunology Program, Division of basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, NL, Canada A1B 3V6
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Donovan PJ, De Miguel MP, Hirano MP, Parsons MS, Lincoln AJ. Germ cell biology--from generation to generation. Int J Dev Biol 2002; 45:523-31. [PMID: 11417895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Germ cells hold a unique place in the life cycle of animal species in that they are the cells that will carry the genome on to the next generation. In order to do this they must retain their DNA in a state in which it can be used to recapitulate embryonic development. In the normal life cycle, the germ cells are the only cells that retain this ability to recapitulate development, referred to as developmental totipotency. The molecular mechanisms regulating developmental potency are poorly understood. Recently its has been shown that germ cells can be turned into pluripotent stem cells when cultured in specific polypeptide growth factors that affect their survival and proliferation. The ability to manipulate developmental potency in germ cells with growth factors allows the underlying mechanisms to be dissected. Germ cells are also the only cells that undergo the unique reductive division of meiosis. This too is essential for the ability of germ cells to form the gametes that will carry the genome into the next generation. Arguably meiosis is the most important division in the life of a nascent organism. Defects in meiosis can result in embryonic or fetal loss or, if the animal survives, in the birth of an individual with chromosomal abnormalities. Recent advances in our understanding of meiosis have come from knockout mice and studies on genes identified through studies of human infertility. This review will focus on these two key aspects of germ cell biology, developmental potency and meiosis.
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Affiliation(s)
- P J Donovan
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Abstract
Making informed decisions about the reuse of single-use medical devices requires considerable analysis, study and management buy-in. This article addresses such issues as the prevalence of the practice, the changing standards and guidelines, institutional responsibilities, risk and insurance concerns and the ethical issues posed by the concept of reuse.
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Parsons MS. 5 common legal risks--could these stories have happened to you? Nurs Life 1986; 6:26-30. [PMID: 3640286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
The maze learning ability of six pony foals that had been weaned at birth was compared to that of six foals reared normally. The foals' learning ability was also compared to their mothers' learning ability at the same task; the correct turn in a single choice point maze. The maze learning test was conducted when the foals were 6 to 8 mo old and after the mothered foals had been weaned. There was no significant difference between the ability of orphaned (weaned at birth) and mothered foals in their ability to learn to turn left (6 +/- .7 and 5.1 +/- .1 trials, respectively) or to learn the reversal, to turn right (6.7 +/- .6 and 6.2 +/- .6 trials, respectively). The orphan foals spent significantly more time in the maze in their first exposure to it than the mothered foals (184 +/- 42 vs 55 +/- 15 s. Mann Whitney U = 7, P less than .05). The mothers of the foals (n = 11) learned to turn left as rapidly as the foals (5.9 +/- .7 trials), but they were slower to learn to turn right (9.8 +/- 1.4 vs 6.4 +/- .4 trials, Mann Whitney U = 33, P less than .05), indicating that the younger horses learned more rapidly. There was no correlation between the trials to criteria of the mare and those of her foal, but there was a significant negative correlation between rank in trials to criteria and age (r = -65, P less than .05) when data from the mare and foal trials were combined. The dominance hierarchy of the mares was determined using a paired feeding test in which two horses competed for one bucket of feed. Although there was no correlation between rank in the hierarchy and maze learning ability, there was a correlation between body weight and rank in the hierarchy (r = .7, P less than .05). This may indicate either that heavier horses are likely to be dominant or that horses high in dominance gain more weight. Maternal deprivation did not appear to seriously retard learning of a simple maze by foals, although the orphans moved more slowly initially. The lack of maternal influence on learning is also reflected in the lack of correlation between the mare's learning ability and that of her foal. Young horses appear to learn more rapidly than older horses.
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