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Narsale A, Almanza F, Tran T, Lam B, Seo D, Vu A, Long SA, Cooney L, Serti E, Davies JD. Th2 cell clonal expansion at diagnosis in human type 1 diabetes. Clin Immunol 2023; 257:109829. [PMID: 37907122 DOI: 10.1016/j.clim.2023.109829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/02/2023]
Abstract
Soon after diagnosis with type 1 diabetes (T1D), many patients experience a period of partial remission. A longer partial remission is associated with a better response to treatment, but the mechanism is not known. The frequency of CD4+CD25+CD127hi (127-hi) cells, a cell subset with an anti-inflammatory Th2 bias, correlates positively with length of partial remission. The purpose of this study was to further characterize the nature of the Th2 bias in 127-hi cells. Single cell RNA sequencing paired with TCR sequencing of sorted 127-hi memory cells identifies clonally expanded Th2 clusters in 127-hi cells from T1D, but not from healthy donors. The Th2 clusters express GATA3, GATA3-AS1, PTGDR2, IL17RB, IL4R and IL9R. The existence of 127-hi Th2 cell clonal expansion in T1D suggests that disease factors may induce clonal expansion of 127-hi Th2 cells that prolong partial remission and delay disease progression.
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Affiliation(s)
- Aditi Narsale
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA.
| | - Francisco Almanza
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA.
| | - Theo Tran
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA
| | - Breanna Lam
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA.
| | - David Seo
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA
| | - Alisa Vu
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA.
| | - S Alice Long
- Benaroya Research Institute, 1201 9(th) Ave, Seattle, WA 98101, USA.
| | | | | | - Joanna D Davies
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, San Diego, CA 92121, USA.
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Abancourt L, Le Guévelou J, Taillez A, Vu A, de Crevoisier R, Supiot S, Hennequin C, Chapet O, Blanchard P, Mirabel X, Lartigau É, Pasquier D. [Stereotactic body radiation therapy for primary kidney cancer]. Cancer Radiother 2023; 27:568-572. [PMID: 37543493 DOI: 10.1016/j.canrad.2023.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 08/07/2023]
Abstract
The incidence of primary renal cancer is increasing, particularly in elderly patients who may have comorbidities and/or a surgical contraindications. Stereotactic body radiotherapy has primarily been evaluated retrospectively to date. The most commonly used dose schedules are 40Gy in five fractions, 42Gy in three fractions, and 26Gy in one fraction. The results in terms of local control and toxicity are very encouraging. The advantages of stereotactic body radiotherapy compared to thermal ablative treatments are its non-invasive nature, absence of general anesthesia, ability to treat larger lesions, and those close to the renal hilum. Prospective evaluations are still necessary.
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Affiliation(s)
- L Abancourt
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France
| | - J Le Guévelou
- Radiotherapy department, centre régional de lutte contre le cancer Eugène-Marquis, 35042 Rennes, France
| | - A Taillez
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France
| | - A Vu
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France
| | - R de Crevoisier
- Radiotherapy department, centre régional de lutte contre le cancer Eugène-Marquis, 35042 Rennes, France
| | - S Supiot
- Institut de cancérologie de l'Ouest, centre René-Gauducheau, boulevard Jacques-Monod, 44800 Saint-Herblain, France
| | - C Hennequin
- Service de cancérologie-radiothérapie, hôpital Saint-Louis, université de Paris, 1, avenue Claude-Vellefaux, 75010 Paris, France
| | - O Chapet
- Département of de radiothérapie oncologie, centre hospitalier universitaire Lyon Sud, 165, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France; Université de Lyon, 69000 Lyon, France
| | - P Blanchard
- Département de radiothérapie oncologique, Gustave-Roussy cancer campus, université Paris-Saclay, Oncostat U1018, Inserm, Villejuif, France
| | - X Mirabel
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France
| | - É Lartigau
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France; Univ. Lille & CNRS CRIStAL UMR 9189, Lille, France
| | - D Pasquier
- Département universitaire de radiothérapie, centre Oscar-Lambret, 3, rue Frédéric-Combemale, Lille, France; Univ. Lille & CNRS CRIStAL UMR 9189, Lille, France.
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Vu A, Ngo V, Bui T, Tran T. POS-013 THROMBOTIC MICROANGIOPATHY AFTER COVID-19: LACK OF EVIDENCE OF COMPLEMENT ACTIVATION? A CASE REPORT. Kidney Int Rep 2022. [PMCID: PMC9213007 DOI: 10.1016/j.ekir.2022.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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McNerney KO, Karageorgos S, Ferry GM, Wolpaw AJ, Burudpakdee C, Khurana P, Toland CN, Vemu R, Vu A, Hogarty MD, Bassiri H. TH-MYCN tumors, but not tumor-derived cell lines, are adrenergic lineage, GD2+, and responsive to anti-GD2 antibody therapy. Oncoimmunology 2022; 11:2075204. [PMID: 35646475 PMCID: PMC9132414 DOI: 10.1080/2162402x.2022.2075204] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Neuroblastoma is a commonly lethal solid tumor of childhood and intensive chemoradiotherapy treatment cures ~50% of children with high-risk disease. The addition of immunotherapy using dinutuximab, a monoclonal antibody directed against the GD2 disialoganglioside expressed on neuroblasts, improves survival when incorporated into front-line therapy and shows robust activity in regressing relapsed disease when combined with chemotherapy. Still, many children succumb to neuroblastoma progression despite receiving dinutuximab-based immunotherapy, and efforts to counteract the immune suppressive signals responsible are warranted. Animal models of human cancers provide useful platforms to study immunotherapies. TH-MYCN transgenic mice are immunocompetent and develop neuroblastomas at autochthonous sites due to enforced MYCN expression in developing neural crest tissues. However, GD2-directed immunotherapy in this model has been underutilized due to the prevailing notion that TH-MYCN neuroblasts express insufficient GD2 to be targeted. We demonstrate that neuroblasts in TH-MYCN-driven tumors express GD2 at levels comparable to human neuroblastomas but rapidly lose GD2 expression when explanted ex vivo to establish tumor cell lines. This occurs in association with a transition from an adrenergic to mesenchymal differentiation state. Importantly, not only is GD2 expression retained on tumors in situ, treatment with a murine anti-GD2 antibody, 14G2a, markedly extends survival in such mice, including durable complete responses. Tumors in 14G2a-treated mice have fewer macrophage and myeloid-derived suppressor cells in their tumor microenvironment. Our findings support the utility of this model to inform immunotherapy approaches for neuroblastoma and potential opportunities to investigate drivers of adrenergic to mesenchymal fate decisions.
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Affiliation(s)
- KO McNerney
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - S Karageorgos
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - GM Ferry
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - AJ Wolpaw
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- The Wistar Institute, Philadelphia, PA
| | - C Burudpakdee
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - P Khurana
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - CN Toland
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - R Vemu
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - A Vu
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - MD Hogarty
- Division of Oncology, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - H Bassiri
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Lucia F, Vu A, Bourbonne V, Pradier O, Abgral R, Schick U. PO-1002 Variability of pretherapeutic FDG PET/CT parameters in patients with head and neck cancers. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07453-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Meerhoff L, Bruneau J, Vu A, Olivier AH, Pettré J. Guided by gaze: Prioritization strategy when navigating through a virtual crowd can be assessed through gaze activity. Acta Psychol (Amst) 2018; 190:248-257. [PMID: 30149239 DOI: 10.1016/j.actpsy.2018.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/31/2018] [Accepted: 07/31/2018] [Indexed: 11/27/2022] Open
Abstract
Modelling crowd behavior is essential for the management of mass events and pedestrian traffic. Current microscopic approaches consider the individual's behavior to predict the effect of individual actions in local interactions on the collective scale of the crowd motion. Recent developments in the use of virtual reality as an experimental tool have offered an opportunity to extend the understanding of these interactions in controlled and repeatable settings. Nevertheless, based on kinematics alone, it remains difficult to tease out how these interactions unfold. Therefore, we tested the hypothesis that gaze activity provides additional information about pedestrian interactions. Using an eye tracker, we recorded the participant's gaze behavior whilst navigating through a virtual crowd. Results revealed that gaze was consistently attracted to virtual walkers with the smallest values of distance at closest approach (DCA) and time to closest approach (TtCA), indicating a higher risk of collision. Moreover, virtual walkers gazed upon before an avoidance maneuver was initiated had a high risk of collision and were typically avoided in the subsequent avoidance maneuver. We argue that humans navigate through crowds by selecting only few interactions and that gaze reveals how a walker prioritizes these interactions. Moreover, we pose that combining kinematic and gaze data provides new opportunities for studying how interactions are selected by pedestrians walking through crowded dynamic environments.
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Wirtz AL, Glass N, Pham K, Perrin N, Rubenstein LS, Singh S, Vu A. Comprehensive development and testing of the ASIST-GBV, a screening tool for responding to gender-based violence among women in humanitarian settings. Confl Health 2016; 10:7. [PMID: 27099617 PMCID: PMC4837612 DOI: 10.1186/s13031-016-0071-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 02/08/2016] [Indexed: 11/10/2022] Open
Abstract
Background Conflict affected refugees and internally displaced persons (IDPs) are at increased vulnerability to gender-based violence (GBV). Health, psychosocial, and protection services have been implemented in humanitarian settings, but GBV remains under-reported and available services under-utilized. To improve access to existing GBV services and facilitate reporting, the ASIST-GBV screening tool was developed and tested for use in humanitarian settings. This process was completed in four phases: 1) systematic literature review, 2) qualitative research that included individual interviews and focus groups with GBV survivors and service providers, respectively, 3) pilot testing of the developed screening tool, and 4) 3-month implementation testing of the screening tool. Research was conducted among female refugees, aged ≥15 years in Ethiopia, and female IDPs, aged ≥18 years in Colombia. Results The systematic review and meta-analysis identified a range of GBV experiences and estimated a 21.4 % prevalence of sexual violence (95 % CI:14.9-28.7) among conflict-affected populations. No existing screening tools for GBV in humanitarian settings were identified. Qualitative research with GBV survivors in Ethiopia and Colombia found multiple forms of GBV experienced by refugees and IDPs that occurred during conflict, in transit, and in displaced settings. Identified forms of violence were combined into seven key items on the screening tool: threats of violence, physical violence, forced sex, sexual exploitation, forced pregnancy, forced abortion, and early or forced marriage. Cognitive testing further refined the tool. Pilot testing in both sites demonstrated preliminary feasibility where 64.8 % of participants in Ethiopia and 44.9 % of participants in Colombia were identified with recent (last 12 months) cases of GBV. Implementation testing of the screening tool, conducted as a routine service in camp/district hospitals, allowed for identification of GBV cases and referrals to services. In this phase, 50.6 % of participants in Ethiopia and 63.4 % in Colombia screened positive for recent experiences of GBV. Psychometric testing demonstrated appropriate internal consistency of the tool (Cronbach’s α = 0.77) and item response theory demonstrated appropriate discrimination and difficulty of the tool. Conclusion The ASIST-GBV screening tool has demonstrated utility and validity for use in confidential identification and referral of refugees and IDPs who experience GBV.
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Affiliation(s)
- A L Wirtz
- Center for Public Health and Human Rights, Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, USA
| | - N Glass
- Johns Hopkins School of Nursing, Baltimore, USA
| | - K Pham
- Department of Emergency Medicine, Johns Hopkins Medical Institute, Baltimore, USA ; Department of International Health, Johns Hopkins School of Public Health, Baltimore, USA
| | - N Perrin
- Johns Hopkins School of Nursing, Baltimore, USA ; Center for Health Research, Kaiser Permanente Northwest, Portland, USA
| | - L S Rubenstein
- Center for Public Health and Human Rights, Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, USA
| | - S Singh
- Department of Internal Medicine, Johns Hopkins Medical Institute, Baltimore, USA
| | - A Vu
- Department of Emergency Medicine, Johns Hopkins Medical Institute, Baltimore, USA ; Department of International Health, Johns Hopkins School of Public Health, Baltimore, USA
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Deininger K, Vu A, Page R, Ambardekar A, Lindenfeld J, Aquilante C. CYP3A5 Pharmacogenetic Testing Predicts High Tacrolimus Dose Requirements Early after Cardiac Transplantation. J Heart Lung Transplant 2016. [DOI: 10.1016/j.healun.2016.01.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Abstract
Narrow Band Imaging (NBI) is an endoscopic optical imaging enhancement technology that improves the contrast of mucosal surface texture, and enhances visualisation of mucosal and submucosal vasculature. White light is filtered to emit two 30-nm narrow bands of blue (415 nm) and green light (540 nm) light simultaneously, the former corresponding to the main peak absorption spectrum of haemoglobin, and the latter allowing visualisation of blood vessels in the deeper mucosal and submucosal layers. NBI has been used to better assess oral potentially malignant disorders (OPMD), identify oral and oropharyngeal squamous cell carcinoma (SCC), and to define surgical margins of head and neck malignancies. NBI shows great potential in improving detection rates of OPMD, facilitating better assessment of oral and oropharyngeal SCC, and reducing the risk of recurrence for oral SCC. Although further research is required to better understand and define intrapapillary capillary loop (IPCL) patterns and to relate these with clinical, histopathological and molecular parameters especially for early mucosal changes, there is building evidence to recommend its use as the new gold standard for endoscopic assessment in head and neck oncology.
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Affiliation(s)
- A Vu
- The Australian Centre for Oral Oncology Research & Education, School of Dentistry, University of Western Australia, Nedlands, Australia
| | - C S Farah
- The Australian Centre for Oral Oncology Research & Education, School of Dentistry, University of Western Australia, Nedlands, Australia
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Vu A, Page R, Roscoe N, Lindenfeld J, Aquilante C. Effect of CYP3A4*22 and CYP3A5 Combined Genotypes on Tacrolimus Disposition in Heart Transplantation. J Heart Lung Transplant 2014. [DOI: 10.1016/j.healun.2014.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Richardson M, Vu A, Karp D, Treszezamsky A. A Prospective Multicenter FPRN Study on the Effect of Sacral Neuromodulation on Bowel Function in Women Undergoing Interstim for Overactive Bladder. J Minim Invasive Gynecol 2014. [DOI: 10.1016/j.jmig.2013.12.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Stansbury D, Naselaris T, Vu A, Gallant J. Visual cortex represents the statistical distributions of objects in natural scenes. J Vis 2010. [DOI: 10.1167/10.7.1260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Ahmad M, Liu Y, Slavens Z, Low R, Merkle E, Hwang K, Vu A, Ma J. SU-FF-I-124: Automatic Identification of Water and Fat Images From a Symmetrically-Sampled Dual-Echo Dixon Technique. Med Phys 2009. [DOI: 10.1118/1.3181245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Abstract
Absolute value of access flow (QA) and change in flow (deltaQA) over time are major determinants of access patency. However, QA may change in response to variation in systemic hemodynamics among dialysis sessions. We examined the effect of mean arterial pressure (MAP), cardiac output (CO), and segmental resistances (R) on QA. Access flow and CO (L/min) were determined by Transonic ultrasound dilution. Static intra-access pressures (mm Hg) at the arterial segment (AS) and venous segment (VS) were determined with the access unoccluded. During access occlusion (O), the AS pressure was equated to arterial pressure (MAPo), whereas the VS pressure reflected venous pressure (VP). Total and segmental vascular resistances (mm Hg-min/L) were calculated as deltaP/Q. We studied 58 arteriovenous (AV) grafts and 35 autologous AV fistulae (AVF) with measurements on two or more occasions in 43 grafts and 25 AVF. MAPC differed from MAPo by >20 mm Hg in 22% of patients. AS (58 +/- 2 vs. 31 +/- 2) and VS (40 +/- 1 vs. 25 +/- 2) were greater in grafts than in AVF, whereas VP was equal. Access flow (0.91 +/- 0.03 vs. 0.91 +/- 0.05 L/min), cardiac output (5.1 +/- 0.1 vs. 5.5 +/- 0.2 L/min), and total access resistance (115 +/- 5 vs. 11 +/- 6) were equal in grafts and AVF, but non-access systemic R was lower in patients with AVF that those with grafts (26 +/- 1 vs. 30 +/- 1). AS and VS resistances were greater in AVF than grafts (87 +/- 6 vs. 54 +/- 3 and 37 +/- 3 vs. 16 +/- 3). Multivariate analysis indicated that CO and ipsilateral MAPo affected flow in both access types. In grafts, all three access resistance elements, AS, VS, and total independently influenced flow, whereas in AVF, the VS did not. Unexpectedly, the ratio of systemic to access resistance also influenced access flow. The pressure in the venous system draining the access affected access flow in AVF but not grafts. We conclude that the hemodynamics of grafts and AVF differ. Cardiac output, MAP, and the arterial segment resistance influence QA in both access types and need to be considered when evaluating QA as part of the trend analysis for detecting access dysfunction.
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Affiliation(s)
- A Besarab
- Department of Medicine, West Virginia University School of Medicine, Henry Ford Hospital, USA
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D'hermies F, Meyer A, Morel X, Halhal M, Vu A, Elmaleh C, Bourgade JM, Cisneros B, Behar-Cohen F, Parent De Curzon H, Renard G. [Papillomatous and nevus of the caruncle]. J Fr Ophtalmol 2001; 24:209-12. [PMID: 11240499] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
A 63-year-old male patient was operated of a single conjunctival papillomatous lesion located on the left caruncle. The curative tumoral excision was followed by its histological analysis. Histologically, the tumor associated an epithelial squamous papilloma with a subepithelial nevus, confirming a combination of two different lesions.
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Affiliation(s)
- F D'hermies
- Service d'Ophtalmologie (Pr. Renard), Hotel Dieu, 1, place du Parvis-Notre-Dame, F-75181 Paris Cedex 04
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Liu C, Marshall P, Schreibman I, Vu A, Gai W, Whitlow M. Interaction between terminal complement proteins C5b-7 and anionic phospholipids. Blood 1999; 93:2297-301. [PMID: 10090939] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
We have recently shown that C5b-6 binds to the erythrocyte membrane via an ionic interaction with sialic acid before the addition of C7 and subsequent membrane insertion. In this study we assessed the role of anionic lipids in the binding of the terminal complement proteins to the membrane and the efficiency of subsequent hemolysis. Human erythrocytes were modified by insertion of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylserine (DPPS), dipalmitoyl phosphatidylethanolamine (DPPE), or dipalmitoyl phosphatidic acid (DPPA). Lipid incorporation and the hemolytic assays were done in the presence of 100 micromol/L sodium orthovanadate to prevent enzymatic redistribution of lipid. We found that the neutral lipids, DPPC and DPPE, did not affect C5b-7 uptake or hemolysis by C5b-9. In contrast, the two acidic phospholipids, DPPS and DPPA, caused a dose-dependent increase in both lysis and C5b-7 uptake. We conclude that the presence of anionic lipids on the exterior face of the membrane increases C5b-7 uptake and subsequent hemolysis. It is known that sickle cell erythrocytes have increased exposure of phosphatidylserine on their external face and are abnormally sensitive to lysis by C5b-9. The data presented here provide a plausible mechanism for this increased sensitivity.
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Affiliation(s)
- C Liu
- Division of Dermatology, Manhattan Veteran's Administration Medical Center, New York, NY 10010-5050, USA
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