629 results on '"E, Hammer"'
Search Results
2. Multiphysiologic State Computational Fluid Dynamics Modeling for Planning Fontan With Interrupted Inferior Vena Cava
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David M. Hoganson, MD, Vijay Govindarajan, PhD, Noah E. Schulz, MS, Emily R. Eickhoff, MS, Roger E. Breitbart, MD, Gerald R. Marx, MD, Pedro J. del Nido, MD, and Peter E. Hammer, PhD
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3D model ,flow modeling ,Fontan ,single ventricle ,virtual surgery ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Background: Single ventricle (SV) patients with interrupted inferior vena cava (iIVC) and azygos continuation are at high risk for unbalanced hepatic venous flow (HVF) distribution to the lungs after Fontan completion and subsequent pulmonary arteriovenous malformations (AVMs) formation. Objectives: The aim of the study was to utilize computational fluid dynamics (CFD) analysis to avoid maldistribution of HVF to the lungs after Fontan surgery. Methods: Four SV subjects with iIVC were prospectively studied with a 3-dimensional (3D) modeling workflow with digital 3D models created from segmented magnetic resonance images or computer tomography scans, virtual surgery, and CFD analysis over multiple physiologic states for the evaluation of operative plans to achieve balanced HVF to both lungs. Three of the patients were Fontan revision candidates with existing AVMs. All patients underwent Fontan completion or revision surgery. Results: CFD predicted that existing or proposed Fontan completion in all patients would result in 100% of HVF to one lung. Improved HVF balance was achieved with CFD analysis of alternative surgical approaches resulting in the average distribution of HVF to the right/left pulmonary arteries of 37%/63% ± 10.4%. A hepatoazygos shunt was required in all patients and additional creation of an innominate vein in one. CFD analysis was validated by the comparison of pre-operative predicted and postoperative MRI-measured total right/left pulmonary flow (51%/49% ± 5.4% vs 49%/51% ± 8.5%). Conclusions: A 3D modeling workflow with CFD simulation for SV patients with iIVC may avoid HVF maldistribution and development of AVMs after Fontan completion.
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- 2024
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3. A local drug delivery system prolongs graft survival by dampening T cell infiltration and neutrophil extracellular trap formation in vascularized composite allografts
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Isabel Arenas Hoyos, Anja Helmer, Anaïs Yerly, Ioana Lese, Stefanie Hirsiger, Lei Zhang, Daniela Casoni, Luisana Garcia, MariaFrancesca Petrucci, Sabine E. Hammer, Tereza Duckova, Yara Banz, Matteo Montani, Mihai Constantinescu, Esther Vögelin, Gregor Bordon, Simone Aleandri, Jean-Christophe Prost, Adriano Taddeo, Paola Luciani, Robert Rieben, Nicoletta Sorvillo, and Radu Olariu
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vascularized composite allotransplantation (VCA) ,transplantation immunology ,tacrolimus ,local immunosuppression ,calcineurin inhibitors (CNIs) ,drug delivery systems (DDSs) ,Immunologic diseases. Allergy ,RC581-607 - Abstract
IntroductionThe standard treatment for preventing rejection in vascularized composite allotransplantation (VCA) currently relies on systemic immunosuppression, which exposes the host to well-known side effects. Locally administered immunosuppression strategies have shown promising results to bypass this hurdle. Nevertheless, their progress has been slow, partially attributed to a limited understanding of the essential mechanisms underlying graft rejection. Recent discoveries highlight the crucial involvement of innate immune components, such as neutrophil extracellular traps (NETs), in organ transplantation. Here we aimed to prolong graft survival through a tacrolimus-based drug delivery system and to understand the role of NETs in VCA graft rejection.MethodsTo prevent off-target toxicity and promote graft survival, we tested a locally administered tacrolimus-loaded on-demand drug delivery system (TGMS-TAC) in a multiple MHC-mismatched porcine VCA model. Off-target toxicity was assessed in tissue and blood. Graft rejection was evaluated macroscopically while the complement system, T cells, neutrophils and NETs were analyzed in graft tissues by immunofluorescence and/or western blot. Plasmatic levels of inflammatory cytokines were measured using a Luminex magnetic-bead porcine panel, and NETs were measured in plasma and tissue using DNA-MPO ELISA. Lastly, to evaluate the effect of tacrolimus on NET formation, NETs were induced in-vitro in porcine and human peripheral neutrophils following incubation with tacrolimus.ResultsRepeated intra-graft administrations of TGMS-TAC minimized systemic toxicity and prolonged graft survival. Nevertheless, signs of rejection were observed at endpoint. Systemically, there were no increases in cytokine levels, complement anaphylatoxins, T-cell subpopulations, or neutrophils during rejection. Yet, tissue analysis showed local infiltration of T cells and neutrophils, together with neutrophil extracellular traps (NETs) in rejected grafts. Interestingly, intra-graft administration of tacrolimus contributed to a reduction in both T-cellular infiltration and NETs. In fact, in-vitro NETosis assessment showed a 62–84% reduction in NETs after stimulated neutrophils were treated with tacrolimus.ConclusionOur data indicate that the proposed local delivery of immunosuppression avoids off-target toxicity while prolonging graft survival in a multiple MHC-mismatch VCA model. Furthermore, NETs are found to play a role in graft rejection and could therefore be a potential innovative therapeutic target.
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- 2024
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4. Flowcytometric data of intermediate-large cell gastrointestinal lymphoma presenting a gross mass in 32 cats – 'let them glow in the flow'
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Barbara C. Rütgen, Birgitt Wolfesberger, Daniel Baumgartner, Sabine E. Hammer, Sandra Groiss, Katharina M. Hittmair, Gabriele Gradner, Andrea Fuchs-Baumgartinger, Taryn A. Donovan, and Ilse Schwendenwein
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feline lymphoma ,flow cytometry ,immunophenotyping ,gastrointestinal ,WHO classification ,Veterinary medicine ,SF600-1100 - Abstract
Gastrointestinal lymphoma is the most common form of lymphoma in domestic cats. Aggressive phenotypes are much less common but do bear and unfavorable prognosis. Immunophenotyping by flow cytometry (FCM) is not systematically performed in these patients, because of difficulties in the acquisition of suitable sample material from the gastrointestinal tract. A multimodal diagnostic approach is recommended to improve identification of subtypes targeting patient tailored therapeutic strategies. The aim of this prospective study was to present results of multicolor FCM immunophenotyping in surgically removed gastrointestinal mass and relate them with histopathology using the World Health Organization (WHO) classification and clonality PCR testing. Thirty-two patients were included. Eight cats (25%) had gastric, 23 (72%) had intestinal lymphoma and 1 (3%) had gastric/jejunal lymphoma. Intestinal lymphoma sites were represented by 18 small intestinal, 4 ileocaecal, 1 large intestinal. All gastric lymphomas were diffuse large B-cell lymphoma (DLBCL). Small intestinal lymphomas were 10 enteropathy associated T-cell lymphoma type I (EATL I), 2 enteropathy associated T-cell lymphoma type II (EATL II), 2 peripheral T-cell lymphoma (PTCL), 3 DLBCL and one DLBCL+EATL II. The most common small intestinal FCM T-cell phenotype was CD3+CD21− CD4−CD8−CD18+ CD5−CD79− in 7/10 EATL I and one EATL II. The most frequent FCM B-cell phenotype was CD3−CD21+ CD4−CD8−CD18+ CD5−CD79+ in 13/17 DLBCL and the DLBCL+EATL II. Clonality PCR results were positive in 87.5% (28/32) of all cases. No cross-lineage rearrangement was observed. IHC and FCM results agreed in 87.5% (28/32) of all cases. When all 3 methods were combined, consistent results were seen in 75% (24/32). This is the first demonstration of a multicolor FCM approach set in context to the gold standard histopathology and clonality testing results.
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- 2024
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5. Exploratory screening for micro-RNA biomarkers in canine multicentric lymphoma
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Sabine E. Hammer, Julia Sprung, Ondřej Škor, Stefanie Burger, Martin Hofer, Ilse Schwendenwein, and Barbara C. Rütgen
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Canis lupus familiaris ,diffuse large B-cell lymphoma (DLBCL) ,peripheral T-cell lymphoma (PTCL) ,microRNA expression analysis ,potential biomarker candidates ,animal model ,Veterinary medicine ,SF600-1100 - Abstract
Lymphoma is one of the most frequent hematopoietic tumors in dogs and shares similar features with human counterparts. MicroRNAs (miRNA, small non-coding RNAs) are pivotal in gene regulation fine tuning and cancer hallmarks are influenced by their aberrant expression. Consequently, miRNA biomarkers may assist predicting therapeutic response and clinical outcome by providing less-invasive novel diagnostics tools. The aim of this study was to detect dysregulated miRNAs in lymphomatous lymph node tissues in comparison to lymph node material or PBMCs from healthy control dogs. Potential significant differences in miRNA expression profiles between four lymphoma entities were evaluated. A customized PCR array was utilized to profile 89 canine target miRNAs. Quantification was performed using qPCR, relative expression was determined by the delta–delta Ct method, and p-values were calculated with student’s t-test. In the 14 diffuse large B-cell lymphoma (DLBCL) patients, 28 and 24 different miRNAs were significantly dysregulated compared to lymph node material or PBMCs. Sixteen miRNAs occurred in both control groups, with 12 miRNAs being down- and four miRNAs being upregulated. The six peripheral T-cell lymphoma (PTCL) samples showed 24 and 25 dysregulated miRNAs when compared to the healthy controls. A combined analysis of DLBCL and PTCL samples revealed seven shared and 19 differently expressed miRNAs. Potential biomarkers in T- and B-cell lymphoma could be the miRNA-17/92 cluster and miRNA-181-family together with miRNA-34a and miRNA-150. Diagnostic utility of potential biomarkers must be validated in larger, prospective cohorts of canine lymphoma cases and in higher numbers of physiological patient material.
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- 2024
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6. Evaluating the Role of Titanomagnetite in Bubble Nucleation: Novel Applications of Low Temperature Magnetic Analysis and Textural Characterization of Rhyolite Pumice and Obsidian From Glass Mountain, California
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Kelly N. McCartney, Julia E. Hammer, Thomas Shea, Stefanie Brachfeld, and Thomas Giachetti
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titanomagnetite ,nanolites ,rhyolite ,heterogeneous bubble nucleation ,rock magnetism ,Geophysics. Cosmic physics ,QC801-809 ,Geology ,QE1-996.5 - Abstract
Abstract Nucleation of H2O vapor bubbles in magma requires surpassing a chemical supersaturation threshold via decompression. The threshold is minimized in the presence of a nucleation substrate (heterogeneous nucleation, 100 MPa). The existence of explosively erupted aphyric rhyolite magma staged from shallow (
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- 2024
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7. Evaluating the Role of Titanomagnetite in Bubble Nucleation: Rock Magnetic Detection and Characterization of Nanolites and Ultra‐Nanolites in Rhyolite Pumice and Obsidian From Glass Mountain, California
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Stefanie Brachfeld, Kelly N. McCartney, Julia E. Hammer, Thomas Shea, and Thomas Giachetti
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nanolites ,ultra‐nanolites ,titanomagnetite ,rock magnetism ,rhyolite ,bubble nucleation ,Geophysics. Cosmic physics ,QC801-809 ,Geology ,QE1-996.5 - Abstract
Abstract We document the presence, composition, and number density (TND) of titanomagnetite nanolites and ultra‐nanolites in aphyric rhyolitic pumice, obsidian, and vesicular obsidian from the 1060 CE Glass Mountain volcanic eruption of Medicine Lake Volcano, California, using magnetic methods. Curie temperatures indicate compositions of Fe2.40Ti0.60O4 to Fe3O4. Rock‐magnetic parameters sensitive to domain state, which is dependent on grain volume, indicate a range of particle sizes spanning superparamagnetic (10 μm) particles. Cylindrical cores drilled from the centers of individual pumice clasts display anisotropy of magnetic susceptibility with prolate fabrics, with the highest degree of anisotropy coinciding with the highest vesicularity. Fabrics within a pumice clast require particle alignment within a fluid, and are interpreted to result from the upward transport of magma driven by vesiculation, ensuing bubble growth, and shearing in the conduit. Titanomagnetite number density (TND) is calculated from titanomagnetite volume fraction, which is determined from ferromagnetic susceptibility. TND estimates for monospecific assemblages of 1,000 nm–10 nm cubes predict 1012 to 1020 m−3 of solid material, respectively. TND estimates derived using a power law distribution of grain sizes predict 1018 to 1019 m−3. These ranges agree well with TND determinations of 1018 to 1020 m−3 made by McCartney et al. (2024), and are several orders of magnitude larger than the number density of bubbles in these materials. These observations are consistent with the hypothesis that titanomagnetite crystals already existed in extremely high number‐abundance at the time of magma ascent and bubble nucleation.
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- 2024
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8. Comparative analysis of swine leukocyte antigen gene diversity in Göttingen Minipigs
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Sabine E. Hammer, Tereza Duckova, Monica Gociman, Sandra Groiss, Clara P. S. Pernold, Karolin Hacker, Lena Kasper, Julia Sprung, Maria Stadler, Andres Eskjær Jensen, Armin Saalmüller, Nadine Wenzel, and Constanca Figueiredo
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Sus scrofa ,swine leukocyte antigen (SLA) ,polymorphism ,animal model ,biomedical research and development ,transplantation ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Worldwide, pigs represent economically important farm animals, also representing a preferred preclinical large animal model for biomedical studies. The need for swine leukocyte antigen (SLA) typing is increasing with the expanded use of pigs in translational research, infection studies, and for veterinary vaccine design. Göttingen Minipigs (GMP) attract increasing attention as valuable model for pharmacological studies and transplantation research. This study represents a first-time assessment of the SLA gene diversity in Göttingen Minipigs in combination with a comparative metadata analysis with commercial pig lines. As Göttingen Minipigs could harbor private as well as potential novel SLA allele combinations, future research projects would benefit from the characterization of their SLA background. In 209 Göttingen Minipigs, SLA class I (SLA-1, SLA-2, SLA-3) and class II (DRB1, DQB1, DQA) genes were characterized by PCR-based low-resolution (Lr) haplotyping. Criteria and nomenclature used for SLA haplotyping were proposed by the ISAG/IUIS-VIC SLA Nomenclature Committee. Haplotypes were assigned based on the comparison with already known breed or farm-specific allele group combinations. In total, 14 SLA class I and five SLA class II haplotypes were identified in the studied cohort, to manifest in 26 SLA class I but only seven SLA class II genotypes. The most common SLA class I haplotypes Lr-24.0 (SLA-1*15XX or Blank-SLA-3*04:04-SLA-2*06:01~02) and Lr-GMP-3.0 (SLA-1*16:02-SLA-3*03:04-SLA-2*17:01) occurred at frequencies of 23.44 and 18.66%, respectively. For SLA class II, the most prevalent haplotypes Lr-0.21 (DRB1*01XX-DQB1*05XX-DQA*04XX) and Lr-0.03 (DRB1*03:02-DQB1*03:01-DQA*01XX) occurred at frequencies of 38.28 and 30.38%. The comparative metadata analysis revealed that Göttingen Minipigs only share six SLA class I and two SLA class II haplotypes with commercial pig lines. More importantly, despite the limited number of SLA class I haplotypes, the high genotype diversity being observed necessitates pre-experimental SLA background assessment of Göttingen Minipigs in regenerative medicine, allo-transplantation, and xenograft research.
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- 2024
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9. Materiell som vilkår for utforsking innen fagområdet natur, miljø og teknikk i barnehagen
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Anne S. E. Hammer and Liv Torunn Grindheim
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Special aspects of education ,LC8-6691 ,Science - Abstract
Despite international emphasis on the advantage of children’s exploration, there is limited knowledge about how availability of physical materials influence children´s exploratory activities. This paper presents findings from a study that examined the availability and use of materials related to science in 26 Norwegian kindergartens. Data were collected by kindergarten teacher students during their practice in kindergartens. Quantitative data were gathered using checklists, qualitative data by observations of children´s activities involving science related materials. The quantitative and qualitative data were analyzed separately and then together using the three categories of exploratory activities introduced by Neuman: formal activities, informal activities and incidental activities. Our findings surface that most kindergartens had much of the materials listed in the checklist, but much of it was locked up and only a few of the objects, such as vinyl animals and books, were available for children´s informal activities. We also found that formal activities gave stimuli to informal activities, which highlights the importance of including children in collective activities as working with theme or projects over time. Only one of the activities in our data was categorized as incidental. Our findings indicate that benefits of using materials to extend children`s exploration are not taken fully advantage of and should be further discussed and highlighted.
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- 2023
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10. Diverse environmental bacteria displaying activity against Phakopsora pachyrhizi, the cause of soybean rust
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Mathias Twizeyimana, Philip E. Hammer, Esther Gachango, Kelly Craig, Billie Espejo, Matthew B. Biggs, James Kremer, and David J. Ingham
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microorganism bacteria ,biological control ,soybean rust ,antimicrobial activity ,Phakopsora pachyrhizi ,biocontrol ,Plant culture ,SB1-1110 - Abstract
The management of soybean rust (SBR) caused by the obligate fungus Phakopsora pachyrhizi mostly relies on the use of synthetic fungicides, especially in areas where the disease inflicts serious yield losses. The reliance on synthetic fungicides to manage this disease has resulted in resistance of P. pachyrhizi populations to most fungicides. In this study, bacteria isolated from diverse environments were evaluated for their biocontrol potential against P. pachyrhizi using soybean detached-leaf method and on-plant in the growth chamber, greenhouse, and field. Among 998 bacterial isolates evaluated using the detached-leaf method; 58% were isolated from plant-related materials, 27% from soil, 10% from insects, and 5% from other environments. Of the isolates screened, 73 were active (they had ⪖ 75% rust reduction) with an active rate of 7.3%. From the active isolates, 65 isolates were re-tested on-plant in the growth chamber for activity confirmation. In the confirmation test, 49 bacteria isolated from plant-related materials maintained their activity with a confirmation rate of 75%. The majority of bacteria with confirmed activity belonged to the taxonomic classes Bacilli and Gammaproteobacteria (70%). Active isolates were prioritized for greenhouse and field testing based on activity in the initial screen and confirmation test. Six bacterial isolates AFS000009 (Pseudomonas_E chlororaphis), AFS032321 (Bacillus subtilis), AFS042929 (Bacillus_C megaterium), AFS065981 (Bacillus_X simplex_A), AFS090698 (Bacillus_A thuringiensis_S), and AFS097295 (Bacillus_A toyonensis) were selected from those bacteria that maintained activity in the confirmation test and were evaluated in the greenhouse, and five among them were evaluated in the field. From the Alabama field evaluation, all bacterial isolates reduced rust infection as well as azoxystrobin (Quadris® at 0.3 L/ha) used as the fungicide control (P > 0.05). Moreover, the scanning electron micrographs demonstrated evidence of antagonistic activity of AFS000009 and AFS032321 against P. pachyrhizi urediniospores. Bacterial isolates that consistently showed activity comparable to that of azoxystrobin can be improved through fermentation and formulation optimization, developed, and deployed. These bacteria strains would provide a valuable alternative to the synthetic fungicides and could play a useful role in integrated disease management programs for this disease.
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- 2023
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11. One-carbon metabolic enzymes are regulated during cell division and make distinct contributions to the metabolome and cell cycle progression in Saccharomyces cerevisiae
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Staci E Hammer and Michael Polymenis
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Genetics ,QH426-470 - Abstract
AbstractEnzymes of one-carbon (1C) metabolism play pivotal roles in proliferating cells. They are involved in the metabolism of amino acids, nucleotides, and lipids and the supply of all cellular methylations. However, there is limited information about how these enzymes are regulated during cell division and how cell cycle kinetics are affected in several loss-of-function mutants of 1C metabolism. Here, we report that the levels of the S. cerevisiaecho2Δcho2Δ
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- 2023
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12. Acss2/HIF-2 signaling facilitates colon cancer growth and metastasis
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Joseph A. Garcia, Rui Chen, Min Xu, Sarah A. Comerford, Robert E. Hammer, Shelby D. Melton, and Linda A. Feagins
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Medicine ,Science - Abstract
The microenvironment of solid tumors is characterized by oxygen and glucose deprivation. Acss2/HIF-2 signaling coordinates essential genetic regulators including acetate-dependent acetyl CoA synthetase 2 (Acss2), Creb binding protein (Cbp), Sirtuin 1 (Sirt1), and Hypoxia Inducible Factor 2α (HIF-2α). We previously shown in mice that exogenous acetate augments growth and metastasis of flank tumors derived from fibrosarcoma-derived HT1080 cells in an Acss2/HIF-2 dependent manner. Colonic epithelial cells are exposed to the highest acetate levels in the body. We reasoned that colon cancer cells, like fibrosarcoma cells, may respond to acetate in a pro-growth manner. In this study, we examine the role of Acss2/HIF-2 signaling in colon cancer. We find that Acss2/HIF-2 signaling is activated by oxygen or glucose deprivation in two human colon cancer-derived cell lines, HCT116 and HT29, and is crucial for colony formation, migration, and invasion in cell culture studies. Flank tumors derived from HCT116 and HT29 cells exhibit augmented growth in mice when supplemented with exogenous acetate in an Acss2/HIF-2 dependent manner. Finally, Acss2 in human colon cancer samples is most frequently localized in the nucleus, consistent with it having a signaling role. Targeted inhibition of Acss2/HIF-2 signaling may have synergistic effects for some colon cancer patients.
- Published
- 2023
13. Hepatic ribosomal protein S6 (Rps6) insufficiency results in failed bile duct development and loss of hepatocyte viability; a ribosomopathy-like phenotype that is partially p53-dependent.
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Sarah A Comerford, Elizabeth A Hinnant, Yidong Chen, and Robert E Hammer
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Genetics ,QH426-470 - Abstract
Defective ribosome biogenesis (RiBi) underlies a group of clinically diverse human diseases collectively known as the ribosomopathies, core manifestations of which include cytopenias and developmental abnormalities that are believed to stem primarily from an inability to synthesize adequate numbers of ribosomes and concomitant activation of p53. The importance of a correctly functioning RiBi machinery for maintaining tissue homeostasis is illustrated by the observation that, despite having a paucity of certain cell types in early life, ribosomopathy patients have an increased risk for developing cancer later in life. This suggests that hypoproliferative states trigger adaptive responses that can, over time, become maladaptive and inadvertently drive unchecked hyperproliferation and predispose to cancer. Here we describe an experimentally induced ribosomopathy in the mouse and show that a normal level of hepatic ribosomal protein S6 (Rps6) is required for proper bile duct development and preservation of hepatocyte viability and that its insufficiency later promotes overgrowth and predisposes to liver cancer which is accelerated in the absence of the tumor-suppressor PTEN. We also show that the overexpression of c-Myc in the liver ameliorates, while expression of a mutant hyperstable form of p53 partially recapitulates specific aspects of the hepatopathies induced by Rps6 deletion. Surprisingly, co-deletion of p53 in the Rps6-deficient background fails to restore biliary development or significantly improve hepatic function. This study not only reveals a previously unappreciated dependence of the developing liver on adequate levels of Rps6 and exquisitely controlled p53 signaling, but suggests that the increased cancer risk in ribosomopathy patients may, in part, stem from an inability to preserve normal tissue homeostasis in the face of chronic injury and regeneration.
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- 2023
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14. Chemical heterogeneities reveal early rapid cooling of Apollo Troctolite 76535
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William S. Nelson, Julia E. Hammer, Thomas Shea, Eric Hellebrand, and G. Jeffrey Taylor
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Science - Abstract
Chemical heterogeneities in Apollo sample 76535 constrain the magmatic cooling history of the lunar Mg-suite to
- Published
- 2021
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15. Ultraviolet dosage and decontamination efficacy were widely variable across 14 UV devices after testing a dried enveloped ribonucleic acid virus surrogate for SARS-CoV-2
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Tony L. Buhr, Erica Borgers-Klonkowski, Bradford W. Gutting, Emlyn E. Hammer, Shelia M. Hamilton, Brett M. Huhman, Stuart L. Jackson, Neil L. Kennihan, Samuel D. Lilly, John D. Little, Brooke B. Luck, Emily A. Matuczinski, Charles T. Miller, Rachel E. Sides, Vanessa L. Yates, and Alice A. Young
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UV decontamination ,enveloped virus Ф6 ,enveloped virus ,decontamination ,ultraviolet (UV) ,SARS-CoV-2 ,Biotechnology ,TP248.13-248.65 - Abstract
Aims: The dosages and efficacy of 14 ultraviolet (UV) decontamination technologies were measured against a SARS-CoV-2 surrogate virus that was dried onto different materials for laboratory and field testing.Methods and results: A live enveloped, ribonucleic acid (RNA) virus surrogate for SARS-CoV-2 was dried on stainless steel 304 (SS304), Navy Top Coat-painted SS304 (NTC), cardboard, polyurethane, polymethyl methacrylate (PMMA), and acrylonitrile butadiene styrene (ABS) materials at > 8.0 log10 plaque-forming units (PFU) per test coupon. The coupons were then exposed to UV radiation during both laboratory and field testing. Commercial and prototype UV-emitting devices were measured for efficacy: four handheld devices, three room/surface-disinfecting machines, five air disinfection devices, and two larger custom-made machines. UV device dosages ranged from 0.01 to 729 mJ cm−2. The antiviral efficacy among the different UV devices ranged from no decontamination up to nearly achieving sterilization. Importantly, cardboard required far greater dosage than SS304.Conclusion: Enormous variability in dosage and efficacy was measured among the different UV devices. Porous materials limit the utility of UV decontamination.Significance and impact of the study: UV devices have wide variability in dosages, efficacy, hazards, and UV output over time, indicating that each UV device needs independent technical measurement and assessment for product development prior to and during use.
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- 2022
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16. Review: Recent Applications of Gene Editing in Fish Species and Aquatic Medicine
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Anikó Gutási, Sabine E. Hammer, Mansour El-Matbouli, and Mona Saleh
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gene editing ,gene silencing ,aquatic animals ,targeted modification ,CRISPR/Cas9 ,TALENs ,Veterinary medicine ,SF600-1100 ,Zoology ,QL1-991 - Abstract
Gene editing and gene silencing techniques have the potential to revolutionize our knowledge of biology and diseases of fish and other aquatic animals. By using such techniques, it is feasible to change the phenotype and modify cells, tissues and organs of animals in order to cure abnormalities and dysfunctions in the organisms. Gene editing is currently experimental in wide fields of aquaculture, including growth, controlled reproduction, sterility and disease resistance. Zink finger nucleases, TALENs and CRISPR/Cas9 targeted cleavage of the DNA induce favorable changes to site-specific locations. Moreover, gene silencing can be used to inhibit the translation of RNA, namely, to regulate gene expression. This methodology is widely used by researchers to investigate genes involved in different disorders. It is a promising tool in biotechnology and in medicine for investigating gene function and diseases. The production of food fish has increased markedly, making fish and seafood globally more popular. Consequently, the incidence of associated problems and disease outbreaks has also increased. A greater investment in new technologies is therefore needed to overcome such problems in this industry. To put it concisely, the modification of genomic DNA and gene silencing can comprehensively influence aquatic animal medicine in the future. On the ethical side, these precise genetic modifications make it more complicated to recognize genetically modified organisms in nature and can cause several side effects through created mutations. The aim of this review is to summarize the current state of applications of gene modifications and genome editing in fish medicine.
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- 2023
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17. Cytokine production and phenotype of Histomonas meleagridis-specific T cells in the chicken
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Julia Lagler, Taniya Mitra, Selma Schmidt, Alix Pierron, Eleni Vatzia, Maria Stadler, Sabine E. Hammer, Kerstin H. Mair, Beatrice Grafl, Patricia Wernsdorf, Fabienne Rauw, Bénédicte Lambrecht, Dieter Liebhart, and Wilhelm Gerner
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Veterinary medicine ,SF600-1100 - Abstract
Abstract The protozoan parasite Histomonas meleagridis is the causative agent of the re-emerging disease histomonosis of chickens and turkeys. Due to the parasite’s extracellular occurrence, a type-2 differentiation of H. meleagridis-specific T cells has been hypothesized. In contrast, a recent study suggested that IFN-γ mRNA+ cells are involved in protection against histomonosis. However, the phenotype and cytokine production profile of H. meleagridis-specific T cells still awaits elucidation. In this work, clonal cultures of a virulent monoxenic strain of H. meleagridis were used for infecting chickens to detect IFN-γ protein and IL-13 mRNA by intracellular cytokine staining and PrimeFlow™ RNA Assays, respectively, in CD4+ and CD8β+ T cells. Infection was confirmed by characteristic pathological changes in the cecum corresponding with H. meleagridis detection by immunohistochemistry and H. meleagridis-specific antibodies in serum. In splenocytes stimulated either with H. meleagridis antigen or PMA/ionomycin, IFN-γ-producing CD4+ T cells from infected chickens increased in comparison to cells from non-infected birds 2 weeks and 5 weeks post-infection. Additionally, an increase of IFN-γ-producing CD4−CD8β− cells upon H. meleagridis antigen and PMA/ionomycin stimulation was detected. Contrariwise, frequencies of IL-13 mRNA-expressing cells were low even after PMA/ionomycin stimulation and mainly had a CD4−CD8β− phenotype. No clear increase of IL-13+ cells related to H. meleagridis infection could be found. In summary, these data suggest that H. meleagridis infection induces a type-1 differentiation of CD4+ T cells but also of non-CD4+ cells. This phenotype could include γδ T cells, which will be addressed in future studies.
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- 2019
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18. Efficacy and safety of belimumab in paediatric and adult patients with systemic lupus erythematosus: an across-study comparison
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Hermine I Brunner, Nicolino Ruperto, Clarissa A Pilkington, Damon L Bass, Mohamed Okily, Holly Quasny, Fengchun Zhang, Syuji Takei, Carlos Abud-Mendoza, Diego O Viola, Beulah N Ji, David A Roth, Masaaki Mori, Sandra Navarra, Reema Syed, Gina Eriksson, and Anne E Hammer
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Medicine - Published
- 2021
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19. NHE6 depletion corrects ApoE4-mediated synaptic impairments and reduces amyloid plaque load
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Theresa Pohlkamp, Xunde Xian, Connie H Wong, Murat S Durakoglugil, Gordon Chandler Werthmann, Takaomi C Saido, Bret M Evers, Charles L White III, Jade Connor, Robert E Hammer, and Joachim Herz
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ApoE ,Alzheimer's ,NHE6 ,neurodegeneration ,endosome ,trafficking ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Apolipoprotein E4 (ApoE4) is the most important and prevalent risk factor for late-onset Alzheimer’s disease (AD). The isoelectric point of ApoE4 matches the pH of the early endosome (EE), causing its delayed dissociation from ApoE receptors and hence impaired endolysosomal trafficking, disruption of synaptic homeostasis, and reduced amyloid clearance. We have shown that enhancing endosomal acidification by inhibiting the EE-specific sodium-hydrogen exchanger 6 (NHE6) restores vesicular trafficking and normalizes synaptic homeostasis. Remarkably and unexpectedly, loss of NHE6 (encoded by the gene Slc9a6) in mice effectively suppressed amyloid deposition even in the absence of ApoE4, suggesting that accelerated acidification of EEs caused by the absence of NHE6 occludes the effect of ApoE on amyloid plaque formation. NHE6 suppression or inhibition may thus be a universal, ApoE-independent approach to prevent amyloid buildup in the brain. These findings suggest a novel therapeutic approach for the prevention of AD by which partial NHE6 inhibition reverses the ApoE4-induced endolysosomal trafficking defect and reduces plaque load.
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- 2021
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20. Flow Cytometric Assessment of Ki-67 Expression in Lymphocytes From Physiologic Lymph Nodes, Lymphoma Cell Populations and Remnant Normal Cell Populations From Lymphomatous Lymph Nodes
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Barbara C. Rütgen, Daniel Baumgartner, Andrea Fuchs-Baumgartinger, Antonella Rigillo, Ondřej Škor, Sabine E. Hammer, Armin Saalmüller, and Ilse Schwendenwein
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canine lymphoma ,flow cytometry ,immunophenotyping ,Ki-67 ,reference data ,Veterinary medicine ,SF600-1100 - Abstract
Recent literature suggests conventional flow cytometric (FCM) immunophenotyping complemented by Ki-67 FCM assessment as a reliable tool to classify canine lymphomas. Ki-67 expression assessed by FCM is rarely reported in canine lymphoma cases and reference data for normal canine lymph nodes are missing. Moreover, nothing is known about the Ki-67 expression within the occasionally observed remnant cell population within the gates of normal lymphocytes in lymphoma cases. Aim of this study was to compare flow cytometric Ki-67 expression of lymphocyte populations from normal canine lymph nodes, lymphoma cells from World-Health-Organisation (WHO) classified lymphoma patient samples and their neighboring normal remnant cell population. Cryopreserved lymphocyte cell suspensions from normal lymph nodes from eight dogs free of lymphoma served as reference material. Fourteen cases diagnosed by cytology, FCM, clonality testing, histopathology including immunohistochemistry consisting of 10 DLBCL, 1 MZL, 1 PTCL and 2 TZL showed a residual small lymphocyte population and were investigated. The Ki-67 expression in normal canine lymphoid tissue was 3.19 ± 2.17%. Mean Ki-67 expression in the malignant cell populations was 41 ± 24.36%. Ki-67 positivity was 12.34 ± 10.68% in the residual physiologic lymphocyte population, which otherwise exhibited a physiologic immunophenotype pattern. This ratio was equivalent (n = 3) or lower (n = 11) than the Ki-67 expression of the malignant cell population within the sample. This is the first report of FCM derived Ki-67 expression combined with immunophenotype patterns in normal canine lymph nodes, compared with lymphoma cell populations and residual normal cell populations of lymphoma cases diagnosed by state of the art technology.
- Published
- 2021
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21. Save the children by treating their mothers (PriVileG-M-study) - study protocol: a sequentially randomized controlled trial of individualized psychotherapy and telemedicine to reduce mental stress in pregnant women and young mothers and to improve Child’s health
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M. Bischoff, V. Howland, J. Klinger-König, S. Tomczyk, S. Schmidt, M. Zygmunt, M. Heckmann, N. van den Berg, B. Bethke, J. Corleis, S. Günther, K. Liutkus, U. Stentzel, A. Neumann, P. Penndorf, T. Ludwig, E. Hammer, T. Winter, and H. J. Grabe
- Subjects
Maternal mental health ,Pregnancy ,Intervention ,Ecological momentary assessment ,Attachment ,Cortisol ,Psychiatry ,RC435-571 - Abstract
Abstract Background As early as pregnancy, maternal mental stress impinges on the child’s development and health. Thus, this may cause enhanced risk for premature birth, lowered fetal growth, and lower fetal birth weight as well as enhanced levels of the stress hormone cortisol and lowered levels of the bonding hormone oxytocin. Maternal stress further reduces maternal sensitivity for the child’s needs which impairs the mother-child-interaction and bonding. Therefore, prevention and intervention studies on mental stress are necessary, beginning prenatally and applying rigorous research methodology, such as randomized controlled trials, to ensure high validity. Methods A randomized controlled trial is used to assess the impact of psychotherapy and telemedicine on maternal mental stress and the child’s mental and physical health. Mentally stressed pregnant women are randomized to an intervention (IG) and a not intervened control group. The IG receives an individualized psychotherapy starting prenatal and lasting for 10 months. Afterwards, a second randomization is used to investigate whether the use of telemedicine can stabilize the therapeutic effects. Using ecological momentary assessments and video recordings, the transfer into daily life, maternal sensitivity and mother-child-bonding are assessed. Psycho-biologically, the synchronicity of cortisol and oxytocin levels between mother and child are assessed as well as the peptidome of the colostrum and breast milk, which are assumed to be essential for the adaptation to the extra-uterine environment. All assessments are compared to an additional control group of healthy women. Finally, the results of the study will lead to the development of a qualification measure for health professionals to detect mental stress, to treat it with low-level interventions and to refer those women with high stress levels to mental health professionals. Discussion The study aims to prevent the transgenerational transfer of psychiatric and somatic disorders from the mother to her child. The effects of the psychotherapy will be stabilized through telemedicine and long-term impacts on the child’s and mothers’ mental health are enhanced. The combination of psychotherapy, telemedicine and methodologies of ecological momentary assessment, video recording and bio banking are new in content-related and methodological manner. Trial registration German Clinical Trials Register: DRKS00017065. Registered 02 May 2019. World Health Organization, Universal Trial Number: U1111–1230-9826. Registered 01 April 2019.
- Published
- 2019
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22. Identification of MHC-I-Presented Porcine Respiratory and Reproductive Syndrome Virus (PRRSV) Peptides Reveals Immunogenic Epitopes within Several Non-Structural Proteins Recognized by CD8+ T Cells
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Marlene Mötz, Melissa R. Stas, Sabine E. Hammer, Tereza Duckova, Frederic Fontaine, Alexandra Kiesler, Kerstin Seitz, Andrea Ladinig, André C. Müller, Christiane Riedel, Armin Saalmüller, and Till Rümenapf
- Subjects
porcine reproductive and respiratory syndrome virus ,PRRSV ,Arteriviridae ,CD8+ T cells ,epitopes ,swine leukocyte antigen class I ,Microbiology ,QR1-502 - Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most relevant porcine pathogens worldwide. Active control of the disease relies on modified live virus vaccines (MLVs), as most inactivated vaccines provide very limited protection. Neutralizing antibodies occur late in infection; therefore, CD8+ T cells are considered important correlates of protection and are a frequent focus of investigation. Our aim was to identify viral peptides naturally bound by the class I major histocompatibility complex (MHC-I) and to confirm their ability to stimulate CD8+ T cells. For this purpose, we immunoprecipitated MHC-I/peptide complexes of PRRSV (strain AUT15-33) -infected cells (SLA-I Lr-Hp 35.0/24 mod) to isolate the viral epitopes and analyzed them with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Furthermore, we employed these identified peptides to stimulate peripheral blood mononuclear cells (PBMCs) of previously PRRSV-infected pigs and measured the PRRSV-specific CD8+ T-cell response with an intracellular cytokine staining (ICS). Our data revealed that PRRSV non-structural proteins (NSPs), encoded in open reading frame 1a and 1b (ORF1), present the major source of MHC-I-presented peptides. Additionally, we show that our identified epitopes are able to trigger IFNγ responses in vitro. These findings are a basis for understanding the proteasomal degradation of PRRSV proteins, the cellular ability to display them via MHC-I, and their potential to restimulate CD8+ T cells.
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- 2022
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23. Hot, Humid Air Decontamination of Aircraft Confirmed That High Temperature and High Humidity Are Critical for Inactivation of Infectious, Enveloped Ribonucleic Acid (RNA) Virus
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Tony L. Buhr, Alice A. Young, Erica Borgers-Klonkowski, Neil L. Kennihan, Harold K. Barnette, Zachary A. Minter, Matthew D. Bohmke, Emily B. Osborn, Shelia M. Hamilton, Monique B. Kimani, Mark W. Hammon, Charles T. Miller, Ryan S. Mackie, Jennifer M. Innocenti, Misty D. Bensman, Bradford W. Gutting, Samuel D. Lilly, Emlyn E. Hammer, Vanessa L. Yates, and Brooke B. Luck
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Φ6 ,enveloped virus ,decontamination ,hot humid air ,aircraft ,Biotechnology ,TP248.13-248.65 - Abstract
Aims: To develop infectious (live/dead) enveloped virus test indicators and response surface methodology (RSM) models that evaluate survival of an enveloped ribonucleic acid (RNA) virus on contaminated aircraft materials after exposure to hot, humid air (HHA).Methods and Results: Enveloped RNA bacteriophage Phi6 (Φ6) was dried on wiring insulation, aircraft performance coating (APC), polypropylene, and nylon at ≥ 8 log10 plaque-forming units (PFU) test coupon−1. Only 2.4 log10 inactivation was measured on APC at 70°Celsius (°C), 5% relative humidity (RH) after 24 h. In contrast, HHA RSM models showed a 90% probability of a 7 log10 inactivation at ≥63°C, 90% RH after 1 h, and decontamination kinetics were similar across different materials. HHA decontamination of C-130 and C-17 aircraft showed >7 log10 and ≥5.9 log10 inactivation of enveloped virus on 100 and 110 test indicators, respectively, with a 1-h treatment, excluding ramp-up and ramp-down times.Conclusions: Enveloped RNA virus test indicators were successfully developed, lab tested for HHA decontamination, analyzed for RSM, and field-tested in aircraft demonstrations.Significance and Impact of the Study: The utility of HHA decontamination was demonstrated after inactivating enveloped RNA virus on aircraft with a 1-h HHA treatment within aircraft temperature and RH limits.
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- 2020
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24. Editorial: Research Topic Crystal Nucleation and Growth in Magmatic Suspensions
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Gianluca Iezzi, Julia E. Hammer, Alan Whittington, and Daniel R. Neuville
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nucleation ,crystallization ,solidification ,crystal growth ,rheology ,magmas ,Science - Published
- 2020
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25. Irgm1-deficiency leads to myeloid dysfunction in colon lamina propria and susceptibility to the intestinal pathogen Citrobacter rodentium.
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Gregory A Taylor, Hsin-I Huang, Brian E Fee, Nourhan Youssef, Mark L Jewell, Viviana Cantillana, Alexi A Schoenborn, Allison R Rogala, Anne F Buckley, Carl G Feng, Bruce A Vallance, Ajay S Gulati, and Gianna E Hammer
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
IRGM and its mouse orthologue Irgm1 are dynamin-like proteins that regulate vesicular remodeling, intracellular microbial killing, and pathogen immunity. IRGM dysfunction is linked to inflammatory bowel disease (IBD), and while it is thought that defective intracellular killing of microbes underscores IBD susceptibility, studies have yet to address how IRGM/Irgm1 regulates immunity to microbes relevant to intestinal inflammation. Here we find that loss of Irgm1 confers marked susceptibility to Citrobacter rodentium, a noninvasive intestinal pathogen that models inflammatory responses to intestinal bacteria. Irgm1-deficient mice fail to control C. rodentium outgrowth in the intestine, leading to systemic pathogen spread and host mortality. Surprisingly, susceptibility due to loss of Irgm1 function was not linked to defective intracellular killing of C. rodentium or exaggerated inflammation, but was instead linked to failure to remodel specific colon lamina propria (C-LP) myeloid cells that expand in response to C. rodentium infection and are essential for C. rodentium immunity. Defective immune remodeling was most striking in C-LP monocytes, which were successfully recruited to the infected C-LP, but subsequently underwent apoptosis. Apoptotic susceptibility was induced by C. rodentium infection and was specific to this setting of pathogen infection, and was not apparent in other settings of intestinal inflammation. These studies reveal a novel role for Irgm1 in host defense and suggest that deficiencies in survival and remodeling of C-LP myeloid cells that control inflammatory intestinal bacteria may underpin IBD pathogenesis linked to IRGM dysfunction.
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- 2020
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26. Bronze Age meat industry: ancient mitochondrial DNA analyses of pig bones from the prehistoric salt mines of Hallstatt (Austria)
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Sabine E. Hammer, Barbara Tautscher, Erich Pucher, Kerstin Kowarik, Hans Reschreiter, Anton Kern, and Elisabeth Haring
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Hallstatt ,Bronze Age ,Sus scrofa ,Ancient DNA ,Mitochondrial DNA ,Phylogeographic network ,Medicine ,Biology (General) ,QH301-705.5 ,Science (General) ,Q1-390 - Abstract
Abstract Objective In the Bronze Age Hallstatt metropolis (‘Salzkammergut’ region, Upper Austria), salt richness enabled the preservation of pork meat to sustain people’s livelihood suggesting an organized meat production industry on a yearly basis of hundreds of pigs. To pattern the geographic and temporal framework of the early management of pig populations in the surrounding areas of Hallstatt, we want to gain insights into the phylogeographic network based on DNA sequence variation among modern pigs, wild boars and prehistoric (likely) domestic pigs. Results In this pilot study, we successfully adapted ancient DNA extraction and sequencing approaches for the analysis of mitochondrial DNA sequence variation in ten prehistoric porcine teeth specimens. Minimum-spanning network analyses revealed unique mitochondrial control region DNA haplotypes ranging within the variation of modern domestic pig and wild boar lineages and even shared haplotypes between prehistoric and modern domestic pigs and wild boars were observed.
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- 2018
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27. Interplay between ChREBP and SREBP-1c coordinates postprandial glycolysis and lipogenesis in livers of mice[S]
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Albert G. Linden, Shili Li, Hwa Y. Choi, Fei Fang, Masashi Fukasawa, Kosaku Uyeda, Robert E. Hammer, Jay D. Horton, Luke J. Engelking, and Guosheng Liang
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carbohydrate-responsive element-binding protein ,sterol regulatory element-binding protein -1c ,adeno-associated virus ,Biochemistry ,QD415-436 - Abstract
Lipogenesis in liver is highest in the postprandial state; insulin activates SREBP-1c, which transcriptionally activates genes involved in FA synthesis, whereas glucose activates carbohydrate-responsive element-binding protein (ChREBP), which activates both glycolysis and FA synthesis. Whether SREBP-1c and ChREBP act independently of one another is unknown. Here, we characterized mice with liver-specific deletion of ChREBP (L-Chrebp−/− mice). Hepatic ChREBP deficiency resulted in reduced mRNA levels of glycolytic and lipogenic enzymes, particularly in response to sucrose refeeding following fasting, a dietary regimen that elicits maximal lipogenesis. mRNA and protein levels of SREBP-1c, a master transcriptional regulator of lipogenesis, were also reduced in L-Chrebp−/− livers. Adeno-associated virus-mediated restoration of nuclear SREBP-1c in L-Chrebp−/− mice normalized expression of a subset of lipogenic genes, while not affecting glycolytic genes. Conversely, ChREBP overexpression alone failed to support expression of lipogenic genes in the livers of mice lacking active SREBPs as a result of Scap deficiency. Together, these data show that SREBP-1c and ChREBP are both required for coordinated induction of glycolytic and lipogenic mRNAs. Whereas SREBP-1c mediates insulin's induction of lipogenic genes, ChREBP mediates glucose's induction of both glycolytic and lipogenic genes. These overlapping, but distinct, actions ensure that the liver synthesizes FAs only when insulin and carbohydrates are both present.
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- 2018
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28. The Role of Elevated Wall Shear Stress in Progression of Pulmonary Vein Stenosis: Evidence from Two Case Studies
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Peter E. Hammer, Kerry McEnaney, Ryan Callahan, Christopher W. Baird, David M. Hoganson, and Kathy J. Jenkins
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pulmonary vein stenosis ,wall shear stress ,neointimal hyperplasia ,Pediatrics ,RJ1-570 - Abstract
Pulmonary vein stenosis is a serious condition characterized by restriction or blockage due to fibrotic tissue ingrowth that develops in the pulmonary veins of infants or children. It is often progressive and can lead to severe pulmonary hypertension and death. Efforts to halt or reverse disease progression include surgery and catheter-based balloon dilation and stent implantation. Its cause and mechanism of progression are unknown. In this pilot study, we propose and explore the hypothesis that elevated wall shear stress at discrete pulmonary venous sites triggers stenosis. To assess this theory, we retrospectively analyzed cardiac catheterization, lung scan, and X-ray computed tomography data to estimate wall shear stress in the pulmonary veins at multiple time points during disease progression in two patients. Results are consistent with the existence of a level of elevated wall shear stress above which the disease is progressive and below which progression is halted. The analysis also suggests the possibility of predicting the target lumen size necessary in a given vein to reduce wall shear stress to normal levels and remove the trigger for stenosis progression.
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- 2021
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29. Expression of T-Bet, Eomesodermin, and GATA-3 Correlates With Distinct Phenotypes and Functional Properties in Porcine γδ T Cells
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Irene M. Rodríguez-Gómez, Stephanie C. Talker, Tobias Käser, Maria Stadler, Lisa Reiter, Andrea Ladinig, Jemma V. Milburn, Sabine E. Hammer, Kerstin H. Mair, Armin Saalmüller, and Wilhelm Gerner
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γδ T cells ,swine ,pig ,T-bet ,Eomes ,GATA-3 ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Unlike mice and humans, porcine γδ T cells represent a prominent subset of T cells in blood and secondary lymphatic organs. GATA-3, T-bet and Eomesodermin (Eomes) are transcription factors with crucial functions in T-cell development and functional differentiation, but their expression has not been investigated in porcine γδ T cells so far. We analyzed the expression of these transcription factors in γδ thymocytes, mature γδ T cells from blood, spleen, lymph nodes, and lung tissue as well as in vitro stimulated γδ T cells on the protein level by flow cytometry. GATA-3 was present in more than 80% of all γδ-thymocytes. Extra-thymic CD2− γδ T cells expressed high levels of GATA-3 in all investigated organs and had a CD8α−/dimCD27+perforin− phenotype. T-bet expression was mainly found in a subset of CD2+ γδ T cells with an opposing CD8αhighCD27dim/−perforin+ phenotype. Eomes+ γδ T cells were also found within CD2+ γδ T cells but were heterogeneous in regard to expression of CD8α, CD27, and perforin. Eomes+ γδ T cells frequently co-expressed T-bet and dominated in the spleen. During aging, CD2−GATA-3+ γδ T cells strongly prevailed in young pigs up to an age of about 2 years but declined in older animals where CD2+T-bet+ γδ T cells became more prominent. Despite high GATA-3 expression levels, IL-4 production could not be found in γδ T cells by intracellular cytokine staining. Experiments with sorted and ConA + IL-2 + IL-12 + IL-18-stimulated CD2− γδ T cells showed that proliferating cells start expressing CD2 and T-bet, produce IFN-γ, but retain GATA-3 expression. In summary, our data suggest a role for GATA-3 in the development of γδ-thymocytes and in the function of peripheral CD2−CD8α−/dimCD27+perforin− γδ T cells. In contrast, T-bet expression appears to be restricted to terminal differentiation stages of CD2+ γδ T cells, frequently coinciding with perforin expression. The functional relevance of high GATA-3 expression levels in extra-thymic CD2− γδ T cells awaits further clarification. However, their unique phenotype suggests that they represent a thymus-derived separate lineage of γδ T cells in the pig for which currently no direct counterpart in rodents or humans has been described.
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- 2019
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30. A substitution mutation in a conserved domain of mammalian acetate-dependent acetyl CoA synthetase 2 results in destabilized protein and impaired HIF-2 signaling.
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Jason S Nagati, Min Xu, Trent Garcia, Sarah A Comerford, Robert E Hammer, and Joseph A Garcia
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Medicine ,Science - Abstract
The response to environmental stresses by eukaryotic organisms includes activation of protective biological mechanisms, orchestrated in part by transcriptional regulators. The tri-member Hypoxia Inducible Factor (HIF) family of DNA-binding transcription factors include HIF-2, which is activated under conditions of oxygen or glucose deprivation. Although oxygen-dependent protein degradation is a key mechanism by which HIF-1 and HIF-2 activity is regulated, HIF-2 is also influenced substantially by the coupled action of acetylation and deacetylation. The acetylation/deacetylation process that HIF-2 undergoes employs a specific acetyltransferase and deacetylase. Likewise, the supply of the acetyl donor, acetyl CoA, used for HIF-2 acetylation originates from a specific acetyl CoA generator, acetate-dependent acetyl CoA synthetase 2 (Acss2). Although Acss2 is predominantly cytosolic, a subset of the Acss2 cellular pool is enriched in the nucleus following oxygen or glucose deprivation. Prevention of nuclear localization by a directed mutation in a putative nuclear localization signal in Acss2 abrogates HIF-2 acetylation and blunts HIF-2 dependent signaling as well as flank tumor growth for knockdown/rescue cancer cells expressing ectopic Acss2. In this study, we report generation of a novel mouse strain using CRISPR/Cas9 mutagenesis that express this mutant Acss2 allele in the mouse germline. The homozygous mutant mice have impaired induction of the canonical HIF-2 target gene erythropoietin and blunted recovery from acute anemia. Surprisingly, Acss2 protein levels are dramatically reduced in these mutant mice. Functional studies investigating the basis for this phenotype reveal multiple protein instability domains in the Acss2 carboxy terminus. The findings described herein may be of relevance in the regulation of native Acss2 protein as well as for humans carrying missense mutations in these domains.
- Published
- 2019
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31. Supplementary Figure Legends from Modeling Renal Cell Carcinoma in Mice: Bap1 and Pbrm1 Inactivation Drive Tumor Grade
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James Brugarolas, Payal Kapur, Renée M. McKay, Robert E. Hammer, Xian-Jin Xie, Meinrad Busslinger, Anwesha Dey, Tao Wang, Ivan Pedrosa, Ananth J. Madhuranthakam, Quyen N. Do, Nicholas Wolff, Tiffani McKenzie, Alana Christie, Shannon Cohn, and Yi-Feng Gu
- Abstract
Supplementary Figure Legends
- Published
- 2023
32. Data from Modulation of Mutant KrasG12D-Driven Lung Tumorigenesis In Vivo by Gain or Loss of PCDH7 Function
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Kathryn A. O'Donnell, Robert E. Hammer, Jingfei Zhu, Emily Stein, James A. Richardson, Shruthy Suresh, Nicole Novaresi, Bethany Smith, Bret M. Evers, Mahesh S. Padanad, and Xiaorong Zhou
- Abstract
PROTOCADHERIN 7 (PCDH7), a transmembrane receptor and member of the Cadherin superfamily, is frequently overexpressed in lung adenocarcinoma and is associated with poor clinical outcome. Although PCDH7 was recently shown to promote transformation and facilitate brain metastasis in lung and breast cancers, decreased PCDH7 expression has also been documented in colorectal, gastric, and invasive bladder cancers. These data suggest context-dependent functions for PCDH7 in distinct tumor types. Given that PCDH7 is a potentially targetable molecule on the surface of cancer cells, further investigation of its role in tumorigenesis in vivo is needed to evaluate the therapeutic potential of its inhibition. Here, we report the analysis of novel PCDH7 gain- and loss-of-function mouse models and provide compelling evidence that this cell-surface protein acts as a potent lung cancer driver. Employing a Cre-inducible transgenic allele, we demonstrated that enforced PCDH7 expression significantly accelerates KrasG12D-driven lung tumorigenesis and potentiates MAPK pathway activation. Furthermore, we performed in vivo somatic genome editing with CRISPR/Cas9 in KrasLSL-G12D; Tp53fl/fl (KP) mice to assess the consequences of PCDH7 loss of function. Inactivation of PCDH7 in KP mice significantly reduced lung tumor development, prolonged survival, and diminished phospho-activation of ERK1/2. Together, these findings establish a critical oncogenic function for PCDH7 in vivo and highlight the therapeutic potential of PCDH7 inhibition for lung cancer. Moreover, given recent reports of elevated or reduced PCDH7 in distinct tumor types, the new inducible transgenic model described here provides a robust experimental system for broadly elucidating the effects of PCDH7 overexpression in vivo.Implications:In this study, we establish a critical oncogenic function for PCDH7 in vivo using novel mouse models and CRISPR/Cas9 genome editing, and we validate the therapeutic potential of PCDH7 inhibition for lung cancer.
- Published
- 2023
33. Supplementary Figure S1 from Modeling Renal Cell Carcinoma in Mice: Bap1 and Pbrm1 Inactivation Drive Tumor Grade
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James Brugarolas, Payal Kapur, Renée M. McKay, Robert E. Hammer, Xian-Jin Xie, Meinrad Busslinger, Anwesha Dey, Tao Wang, Ivan Pedrosa, Ananth J. Madhuranthakam, Quyen N. Do, Nicholas Wolff, Tiffani McKenzie, Alana Christie, Shannon Cohn, and Yi-Feng Gu
- Abstract
Validation of Pax8-Cre;Vhl;Bap1 mice.
- Published
- 2023
34. Figure S1-S5 from Modulation of Mutant KrasG12D-Driven Lung Tumorigenesis In Vivo by Gain or Loss of PCDH7 Function
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Kathryn A. O'Donnell, Robert E. Hammer, Jingfei Zhu, Emily Stein, James A. Richardson, Shruthy Suresh, Nicole Novaresi, Bethany Smith, Bret M. Evers, Mahesh S. Padanad, and Xiaorong Zhou
- Abstract
S1. Generation of PCDH7LSL mice and analysis of lung tumors in vivo. S2. TUNEL staining of lung tumors. S3. Validation of CRISPR/Cas9-editing of Pcdh7. S4. Diminished invasiveness in Pcdh7 depleted KP tumors. S5. Sequences of gene-edited alleles in KP tumors.
- Published
- 2023
35. Inflammatory Th1 and Th17 in the Intestine Are Each Driven by Functionally Specialized Dendritic Cells with Distinct Requirements for MyD88
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Jie Liang, Hsin-I Huang, Fernanda P. Benzatti, Amelia B. Karlsson, Junyi J. Zhang, Nourhan Youssef, Averil Ma, Laura P. Hale, and Gianna E. Hammer
- Subjects
Biology (General) ,QH301-705.5 - Abstract
Summary: Normal dynamics between microbiota and dendritic cells (DCs) support modest numbers of T cells, yet these do not cause inflammation. The DCs that induce inflammatory T cells and the signals that drive this process remain unclear. Here, we demonstrate that small intestine DCs lacking the signaling attenuator A20 induce inflammatory T cells and that the signals perceived and antigen-presenting cell (APC) functions are unique for different DC subsets. Thus, although CD103+CD11b− DCs exclusively instruct IFNγ+ T cells, CD103+CD11b+ DCs exclusively instruct IL-17+ T cells. Surprisingly, APC functions of both DC subsets are upregulated in a MyD88-independent fashion. In contrast, CD103−CD11b+ DCs instruct both IFNγ+ and IL-17+ T cells, and only the IL-17-inducing APC functions require MyD88. In disease pathogenesis, both CD103−CD11b+ and CD103+CD11b+ DCs expand pathologic Th17 cells. Thus, in disease pathogenesis, specific DCs instruct specific inflammatory T cells. : Normal dynamics between microbiota and dendritic cells (DCs) support T cell homeostasis in the small intestine, but the dynamics that drive inflammation are not clear. Liang et al. show that distinct subsets of dendritic cells drive pathogenic Th1 versus Th17 differentiation. Keywords: dendritic cells, small intestine, Th1, Th17, inflammation, MyD88, A20
- Published
- 2016
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36. Chemical and physical influences on aerosol activation in liquid clouds: a study based on observations from the Jungfraujoch, Switzerland
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C. R. Hoyle, C. S. Webster, H. E. Rieder, A. Nenes, E. Hammer, E. Herrmann, M. Gysel, N. Bukowiecki, E. Weingartner, M. Steinbacher, and U. Baltensperger
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
A simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from four summertime Cloud and Aerosol Characterisation Experiments (CLACE) at the high-altitude site Jungfraujoch (JFJ). It is shown that 79 % of the observed variance in droplet numbers can be represented by a model accounting only for the number of potential cloud condensation nuclei (defined as number of particles larger than 80 nm in diameter), while the mean errors in the model representation may be reduced by the addition of further explanatory variables, such as the mixing ratios of O3, CO, and the height of the measurements above cloud base. The statistical model has a similar ability to represent the observed droplet numbers in each of the individual years, as well as for the two predominant local wind directions at the JFJ (northwest and southeast). Given the central European location of the JFJ, with air masses in summer being representative of the free troposphere with regular boundary layer in-mixing via convection, we expect that this statistical model is generally applicable to warm clouds under conditions where droplet formation is aerosol limited (i.e. at relatively high updraught velocities and/or relatively low aerosol number concentrations). A comparison between the statistical model and an established microphysical parametrization shows good agreement between the two and supports the conclusion that cloud droplet formation at the JFJ is predominantly controlled by the number concentration of aerosol particles.
- Published
- 2016
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37. Association of Porcine Swine Leukocyte Antigen (SLA) Haplotypes with B- and T-Cell Immune Response to Foot-and-Mouth Disease Virus (FMDV) Peptides
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Patricia de León, Rodrigo Cañas-Arranz, Yago Saez, Mar Forner, Sira Defaus, Dolores Cuadra, María J. Bustos, Elisa Torres, David Andreu, Esther Blanco, Francisco Sobrino, and Sabine E. Hammer
- Subjects
swine ,foot-and-mouth disease virus ,dendrimer peptide ,swine leukocyte antigen ,SLA polymorphism ,adaptive immunity ,Medicine - Abstract
Dendrimer peptides are promising vaccine candidates against the foot-and-mouth disease virus (FMDV). Several B-cell epitope (B2T) dendrimers, harboring a major FMDV antigenic B-cell site in VP1 protein, are covalently linked to heterotypic T-cell epitopes from 3A and/or 3D proteins, and elicited consistent levels of neutralizing antibodies and IFN-γ-producing cells in pigs. To address the contribution of the highly polymorphic nature of the porcine MHC (SLA, swine leukocyte antigen) on the immunogenicity of B2T dendrimers, low-resolution (Lr) haplotyping was performed. We looked for possible correlations between particular Lr haplotypes with neutralizing antibody and T-cell responses induced by B2T peptides. In this study, 63 pigs immunized with B2T dendrimers and 10 non-immunized (control) animals are analyzed. The results reveal a robust significant correlation between SLA class-II Lr haplotypes and the T-cell response. Similar correlations of T-cell response with SLA class-I Lr haplotypes, and between B-cell antibody response and SLA class-I and SLA class-II Lr haplotypes, were only found when the sample was reduced to animals with Lr haplotypes represented more than once. These results support the contribution of SLA class-II restricted T-cells to the magnitude of the T-cell response and to the antibody response evoked by the B2T dendrimers, being of potential value for peptide vaccine design against FMDV.
- Published
- 2020
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38. Proliferation Activity in Canine Gastrointestinal Lymphoma
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Iwan Burgener, Stefan Kummer, Klemens Alton, Birgitt Wolfesberger, Andrea Fuchs-Baumgartinger, Alexander Tichy, Sabine E. Hammer, Lea Liehmann, Stefanie Burger, Sabine Klinger, Barbara C. Rütgen, and Ingrid Walter
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Pathology ,medicine.medical_specialty ,Mitotic index ,General Veterinary ,Proliferation index ,business.industry ,Significant difference ,Proliferation activity ,medicine.disease ,Gastrointestinal lymphoma ,World health ,Pathology and Forensic Medicine ,Lymphoma ,Dogs ,Ki-67 Antigen ,Immunophenotyping ,Mitotic Index ,medicine ,Animals ,Dog Diseases ,Lymphoma, Large B-Cell, Diffuse ,business ,Cell Proliferation ,Gastrointestinal Neoplasms - Abstract
Summary Gastrointestinal lymphomas are uncommon in dogs and little is known about their distinct subtypes or proliferation rate. The aim of this study was to stratify 33 canine gastrointestinal lymphoma samples according to the latest World Health Organization classification and to determine the Ki67 proliferation index by manual counting, digital image analysis and visual estimation. The Ki67 index was then correlated with subtype, immunophenotype, mitotic index, grade and tumour location. The mitotic index correlated positively with the Ki67 index. A significantly higher number of Ki67-positive cells was found in enteropathy-associated T-cell lymphoma type I and in diffuse large B-cell lymphoma compared with enteropathy-associated T-cell lymphoma type II. There was also a significant difference in Ki67 immunolabelled cells between grade 1 and grade 2 lymphomas. Moderate agreement was found between the Ki67 index as obtained by manual counting and visual estimation, but there was strong agreement between manual counting and digital image analysis. The user-friendly digital imaging system used in this study could have potential for future determination of the Ki67 index in lymphoid neoplasms.
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- 2021
39. Sensitivity estimations for cloud droplet formation in the vicinity of the high-alpine research station Jungfraujoch (3580 m a.s.l.)
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E. Hammer, N. Bukowiecki, B. P. Luo, U. Lohmann, C. Marcolli, E. Weingartner, U. Baltensperger, and C. R. Hoyle
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Aerosol radiative forcing estimates suffer from large uncertainties as a result of insufficient understanding of aerosol–cloud interactions. The main source of these uncertainties is dynamical processes such as turbulence and entrainment but also key aerosol parameters such as aerosol number concentration and size distribution, and to a much lesser extent, the composition. From June to August 2011 a Cloud and Aerosol Characterization Experiment (CLACE2011) was performed at the high-alpine research station Jungfraujoch (Switzerland, 3580 m a.s.l.) focusing on the activation of aerosol to form liquid-phase clouds (in the cloud base temperature range of −8 to 5 °C). With a box model the sensitivity of the effective peak supersaturation (SSpeak), an important parameter for cloud activation, to key aerosol and dynamical parameters was investigated. The updraft velocity, which defines the cooling rate of an air parcel, was found to have the greatest influence on SSpeak. Small-scale variations in the cooling rate with large amplitudes can significantly alter CCN activation. Thus, an accurate knowledge of the air parcel history is required to estimate SSpeak. The results show that the cloud base updraft velocities estimated from the horizontal wind measurements made at the Jungfraujoch can be divided by a factor of approximately 4 to get the updraft velocity required for the model to reproduce the observed SSpeak. The aerosol number concentration and hygroscopic properties were found to be less important than the aerosol size in determining SSpeak. Furthermore turbulence is found to have a maximum influence when SSpeak is between approximately 0.2 and 0.4 %. Simulating the small-scale fluctuations with several amplitudes, frequencies and phases, revealed that independently of the amplitude, the effect of the frequency on SSpeak shows a maximum at 0.46 Hz (median over all phases) and at higher frequencies, the maximum SSpeak decreases again.
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- 2015
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40. Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog
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T. Elias, J.-C. Dupont, E. Hammer, C. R. Hoyle, M. Haeffelin, F. Burnet, and D. Jolivet
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The study assesses the contribution of aerosols to the extinction of visible radiation in the mist–fog–mist cycle. Relative humidity is large in the mist–fog–mist cycle, and aerosols most efficient in interacting with visible radiation are hydrated and compose the accumulation mode. Measurements of the microphysical and optical properties of these hydrated aerosols with diameters larger than 0.4 μm were carried out near Paris, during November 2011, under ambient conditions. Eleven mist–fog–mist cycles were observed, with a cumulated fog duration of 96 h, and a cumulated mist–fog–mist cycle duration of 240 h. In mist, aerosols grew by taking up water at relative humidities larger than 93%, causing a visibility decrease below 5 km. While visibility decreased down from 5 to a few kilometres, the mean size of the hydrated aerosols increased, and their number concentration (Nha) increased from approximately 160 to approximately 600 cm−3. When fog formed, droplets became the strongest contributors to visible radiation extinction, and liquid water content (LWC) increased beyond 7 mg m−3. Hydrated aerosols of the accumulation mode co-existed with droplets, as interstitial non-activated aerosols. Their size continued to increase, and some aerosols achieved diameters larger than 2.5 μm. The mean transition diameter between the aerosol accumulation mode and the small droplet mode was 4.0 ± 1.1 μm. Nha also increased on average by 60 % after fog formation. Consequently, the mean contribution to extinction in fog was 20 ± 15% from hydrated aerosols smaller than 2.5 μm and 6 ± 7% from larger aerosols. The standard deviation was large because of the large variability of Nha in fog, which could be smaller than in mist or 3 times larger. The particle extinction coefficient in fog can be computed as the sum of a droplet component and an aerosol component, which can be approximated by 3.5 Nha (Nha in cm−3 and particle extinction coefficient in Mm−1. We observed an influence of the main formation process on Nha, but not on the contribution to fog extinction by aerosols. Indeed, in fogs formed by stratus lowering (STL), the mean Nha was 360 ± 140 cm−3, close to the value observed in mist, while in fogs formed by nocturnal radiative cooling (RAD) under cloud-free sky, the mean Nha was 600 ± 350 cm−3. But because visibility (extinction) in fog was also lower (larger) in RAD than in STL fogs, the contribution by aerosols to extinction depended little on the fog formation process. Similarly, the proportion of hydrated aerosols over all aerosols (dry and hydrated) did not depend on the fog formation process. Measurements showed that visibility in RAD fogs was smaller than in STL fogs due to three factors: (1) LWC was larger in RAD than in STL fogs, (2) droplets were smaller, (3) hydrated aerosols composing the accumulation mode were more numerous.
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- 2015
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41. Deletion of ELOVL6 blocks the synthesis of oleic acid but does not prevent the development of fatty liver or insulin resistance[S]
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Young-Ah Moon, Courtney R. Ochoa, Matthew A. Mitsche, Robert E. Hammer, and Jay D. Horton
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fatty acid elongation ,palmitic acid ,sterol-regulatory element binding proteins ,Biochemistry ,QD415-436 - Abstract
Elongation of very long chain fatty acid-like family member 6 (ELOVL6) is a fatty acyl elongase that performs the initial and rate-limiting condensing reaction required for microsomal elongation of long-chain fatty acids. Our previous in vitro studies suggested that ELOVL6 elongated long-chain saturated fatty acids and monounsaturated fatty acids with chain lengths of 12 to 16 carbons. Here, we describe the generation and phenotypic characterization of Elovl6−/− mice. As predicted from the in vitro studies, livers from Elovl6−/− mice accumulated palmitic (C16:0) and palmitoleic (C16:1, n-7) fatty acids and contained significantly less stearic (C18:0) and oleic (C18:1, n-9) acids, confirming that ELOVL6 is the only enzyme capable of elongating palmitate (C16:0). Unexpectedly, Elovl6−/− mice produced vaccenic acid (C18:1, n-7), the elongated product of palmitoleate (C16:1, n-7), suggesting that palmitoleate (C16:1, n-7) to vaccenate (C18:1, n-7) elongation was not specific to ELOVL6. The only detected consequence of deleting Elovl6−/− in mice was that their livers accumulated significantly more triglycerides than wild-type mice when fed a fat-free/high-carbohydrate diet. When mice were fed a high-fat diet or ELOVL6 was deleted in ob/ob mice, the absence of ELOVL6 did not alter the development of obesity, fatty liver, hyperglycemia, or hyperinsulinemia. Combined, these results suggest that palmitoleic (C16:1, n-7) and vaccenic (C18:1, n-7) acids can largely replace the roles of oleic acid (C18:1, n-9) in vivo and that the deletion of ELOVL6 does not protect mice from the development of hepatic steatosis or insulin resistance.
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- 2014
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42. The feasibility of mitral valve device foldoplasty: an in vivo study to evaluate durable retention
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Kimberlee Gauvreau, Peter E. Hammer, Isaac Wamala, Mossab Y Saeed, Pedro J. del Nido, Nikolay V. Vasilyev, Daniel Bautista-Salinas, and Sunil J. Ghelani
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Swine ,medicine.medical_treatment ,Experimental ,In vivo ,Mitral valve ,medicine ,Animals ,Embolization ,Cardiac Surgical Procedures ,Reduction (orthopedic surgery) ,Mitral valve repair ,Mitral regurgitation ,Mitral Valve Prolapse ,Leaflet (botany) ,business.industry ,Mitral Valve Insufficiency ,Surgery ,medicine.anatomical_structure ,Feasibility Studies ,Mitral Valve ,Implant ,Cardiology and Cardiovascular Medicine ,business - Abstract
OBJECTIVES We have previously shown in experimental settings that a leaflet foldoplasty device reduces redundant leaflet area to re-establish mitral valve (MV) coaptation. The current study investigates the in vivo device retention and functional durability following foldoplasty. METHODS The prototype is of superelastic nitinol formed into a 3-dimensional shape. It is unfolded to engage a specified area of leaflet tissue and then folded to exclude this tissue from the coaptation surface. Design modifications were made and tested in benchtop studies to determine the optimal design for durable retention within the leaflet. To evaluate in vivo performance, posterior leaflet chordae were severed in Yorkshire pigs to produce complete posterior leaflet prolapse and severe mitral regurgitation. Design modifications were then used for MV repair. Five animals that underwent repair using the optimal design were observed for 2 weeks postoperative to evaluate the functional result and implant retention. RESULTS Device position and orientation were maintained at 2 weeks while preserving the functional MV repair in all 5 animals. Coaptation height was 5.5 ± 1.5 mm, which was not significantly different from a baseline of 4.9 ± 0.8 mm. The degree of leaflet excursion was 41.0 ± 16.0 compared to a baseline of 58.7 ± 27.5. CONCLUSIONS Device foldoplasty is a new concept for MV repair based on the reduction of redundant leaflet tissue area. This study demonstrates the feasibility of safe maintenance of this repair without early dislodgement or embolization.
- Published
- 2021
43. LRP1 integrates murine macrophage cholesterol homeostasis and inflammatory responses in atherosclerosis
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Xunde Xian, Yinyuan Ding, Marco Dieckmann, Li Zhou, Florian Plattner, Mingxia Liu, John S Parks, Robert E Hammer, Philippe Boucher, Shirling Tsai, and Joachim Herz
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LRP1 ,ABCA1 ,macrophage ,atherosclerosis ,phosphorylation ,nuclear hormone receptor ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional cell surface receptor with diverse physiological roles, ranging from cellular uptake of lipoproteins and other cargo by endocytosis to sensor of the extracellular environment and integrator of a wide range of signaling mechanisms. As a chylomicron remnant receptor, LRP1 controls systemic lipid metabolism in concert with the LDL receptor in the liver, whereas in smooth muscle cells (SMC) LRP1 functions as a co-receptor for TGFβ and PDGFRβ in reverse cholesterol transport and the maintenance of vascular wall integrity. Here we used a knockin mouse model to uncover a novel atheroprotective role for LRP1 in macrophages where tyrosine phosphorylation of an NPxY motif in its intracellular domain initiates a signaling cascade along an LRP1/SHC1/PI3K/AKT/PPARγ/LXR axis to regulate and integrate cellular cholesterol homeostasis through the expression of the major cholesterol exporter ABCA1 with apoptotic cell removal and inflammatory responses.
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- 2017
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44. Expression of SREBP-1c Requires SREBP-2-mediated Generation of a Sterol Ligand for LXR in Livers of Mice
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Shunxing Rong, Víctor A Cortés, Shirya Rashid, Norma N Anderson, Jeffrey G McDonald, Guosheng Liang, Young-Ah Moon, Robert E Hammer, and Jay D Horton
- Subjects
SREBP ,LXR ,cholesterol ,fatty acids ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
The synthesis of cholesterol and fatty acids (FA) in the liver is independently regulated by SREBP-2 and SREBP-1c, respectively. Here, we genetically deleted Srebf-2 from hepatocytes and confirmed that SREBP-2 regulates all genes involved in cholesterol biosynthesis, the LDL receptor, and PCSK9; a secreted protein that degrades LDL receptors in the liver. Surprisingly, we found that elimination of Srebf-2 in hepatocytes of mice also markedly reduced SREBP-1c and the expression of all genes involved in FA and triglyceride synthesis that are normally regulated by SREBP-1c. The nuclear receptor LXR is necessary for Srebf-1c transcription. The deletion of Srebf-2 and subsequent lower sterol synthesis in hepatocytes eliminated the production of an endogenous sterol ligand required for LXR activity and SREBP-1c expression. These studies demonstrate that cholesterol and FA synthesis in hepatocytes are coupled and that flux through the cholesterol biosynthetic pathway is required for the maximal SREBP-1c expression and high rates of FA synthesis.
- Published
- 2017
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45. Multilocus Intron Trees Reveal Extensive Male-Biased Homogenization of Ancient Populations of Chamois (Rupicapra spp.) across Europe during Late Pleistocene.
- Author
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Trinidad Pérez, Margarita Fernández, Sabine E Hammer, and Ana Domínguez
- Subjects
Medicine ,Science - Abstract
The inferred phylogenetic relationships between organisms often depend on the molecular marker studied due to the diverse evolutionary mode and unlike evolutionary histories of different parts of the genome. Previous studies have shown conflicting patterns of differentiation of mtDNA and several nuclear markers in chamois (genus Rupicapra) that indicate a complex evolutionary picture. Chamois are mountain caprine that inhabit most of the medium to high altitude mountain ranges of southern Eurasia. The most accepted taxonomical classification considers two species, R. pyrenaica (with the subspecies parva, pyrenaica and ornata) from southwestern Europe and R. rupicapra (with the subspecies cartusiana, rupicapra, tatrica, carpatica, balcanica, asiatica and caucasica) from northeastern Europe. Phylogenies of mtDNA revealed three very old clades (from the early Pleistocene, 1.9 Mya) with a clear geographical signal. Here we analyze a set of 23 autosomal introns, comprising 15,411 nucleotides, in 14 individuals covering the 10 chamois subspecies. Introns offered an evolutionary scenario that contrasts with mtDNA. The nucleotidic diversity was 0.0013± 0.0002, at the low range of what is found in other mammals even if a single species is considered. A coalescent multilocus analysis with *BEAST indicated that introns diversified 88 Kya, in the late Pleistocene, and the effective population size at the root was lower than 10,000 individuals. The dispersal of some few migrant males should have rapidly spread trough the populations of chamois, given the homogeneity of intron sequences. The striking differences between mitochondrial and nuclear markers can be attributed to strong female philopatry and extensive male dispersal. Our results highlight the need of analyzing multiple and varied genome components to capture the complex evolutionary history of organisms.
- Published
- 2017
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46. Size-dependent particle activation properties in fog during the ParisFog 2012/13 field campaign
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E. Hammer, M. Gysel, G. C. Roberts, T. Elias, J. Hofer, C. R. Hoyle, N. Bukowiecki, J.-C. Dupont, F. Burnet, U. Baltensperger, and E. Weingartner
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Fog-induced visibility reduction is responsible for a variety of hazards in the transport sector. Therefore there is a large demand for an improved understanding of fog formation and thus improved forecasts. Improved fog forecasts require a better understanding of the numerous complex mechanisms during the fog life cycle. During winter 2012/13 a field campaign called ParisFog aiming at fog research took place at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research). SIRTA is located about 20 km southwest of the Paris city center, France, in a semi-urban environment. In situ activation properties of the prevailing fog were investigated by measuring (1) total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems; (2) interstitial hydrated aerosol and fog droplet size distributions at ambient conditions; and (3) cloud condensation nuclei (CCN) number concentration at different supersaturations (SS) with a CCN counter. The aerosol particles were characterized regarding their hygroscopic properties, fog droplet activation behavior and contribution to light scattering for 17 developed fog events. Low particle hygroscopicity with an overall median of the hygroscopicity parameter, κ, of 0.14 was found, likely caused by substantial influence from local traffic and wood burning emissions. Measurements of the aerosol size distribution at ambient RH revealed that the critical wet diameter, above which the hydrated aerosols activate to fog droplets, is rather large (with a median value of 2.6μm) and is highly variable (ranging from 1 to 5μm) between the different fog events. Thus, the number of activated fog droplets was very small and the non-activated hydrated particles were found to contribute significantly to the observed light scattering and thus to the reduction in visibility. Combining all experimental data, the effective peak supersaturation, SSpeak, a measure of the peak supersaturation during the fog formation, was determined. The median SSpeak value was estimated to be in the range from 0.031 to 0.046% (upper and lower limit estimations), which is in good agreement with previous experimental and modeling studies of fog.
- Published
- 2014
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47. Investigation of the effective peak supersaturation for liquid-phase clouds at the high-alpine site Jungfraujoch, Switzerland (3580 m a.s.l.)
- Author
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E. Hammer, N. Bukowiecki, M. Gysel, Z. Jurányi, C. R. Hoyle, R. Vogt, U. Baltensperger, and E. Weingartner
- Subjects
Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Aerosols influence the Earth's radiation budget directly through absorption and scattering of solar radiation in the atmosphere but also indirectly by modifying the properties of clouds. However, climate models still suffer from large uncertainties as a result of insufficient understanding of aerosol-cloud interactions. At the high altitude research station Jungfraujoch (JFJ; 3580 m a.s.l., Switzerland) cloud condensation nuclei (CCN) number concentrations at eight different supersaturations (SS) from 0.24% to 1.18% were measured using a CCN counter during Summer 2011. Simultaneously, in-situ aerosol activation properties of the prevailing ambient clouds were investigated by measuring the total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems. Combining all experimental data, a new method was developed to retrieve the so-called effective peak supersaturation SSpeak, as a measure of the SS at which ambient clouds are formed. A 17-month CCN climatology was then used to retrieve the SSpeak values also for four earlier summer campaigns (2000, 2002, 2004 and 2010) where no direct CCN data were available. The SSpeak values varied between 0.01% and 2.0% during all campaigns. An overall median SSpeak of 0.35% and dry activation diameter of 87 nm was observed. It was found that the difference in topography between northwest and southeast plays an important role for the effective peak supersaturation in clouds formed in the vicinity of the JFJ, while differences in the number concentration of potential CCN only play a minor role. Results show that air masses coming from the southeast (with the slowly rising terrain of the Aletsch Glacier) generally experience lower SSpeak values than air masses coming from the northwest (steep slope). The observed overall median values were 0.41% and 0.22% for northwest and southeast wind conditions, respectively, corresponding to literature values for cumulus clouds and shallow-layer clouds. These cloud types are consistent with weather observations routinely performed at the JFJ.
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- 2014
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48. Germline Saturation Mutagenesis Induces Skeletal Phenotypes in Mice
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Anas M. Khanshour, Yongbo Lu, Xudong Xie, Stephen Aplin Lyon, Jamie Russell, Bruce Beutler, Eva Marie Y. Moresco, Aysha B. Khalid, Yang Li, Nandina Paria, Qian Xu, Jian Q. Feng, Joshua E. Mayfield, Kristin Denton, Xiaohong Li, Julia Kozlitina, Robert E. Hammer, Sara Ludwig, Jonathan J. Rios, Amy F Lewanda, Carol Wise, Carlos Ferreira, and Miao Tang
- Subjects
0301 basic medicine ,Endocrinology, Diabetes and Metabolism ,Mutagenesis (molecular biology technique) ,030209 endocrinology & metabolism ,Biology ,Article ,Germline ,Mice ,03 medical and health sciences ,0302 clinical medicine ,In vivo ,Animals ,Humans ,Orthopedics and Sports Medicine ,Saturated mutagenesis ,Gene ,Genetics ,Embryonic stem cell ,Phenotype ,Phosphotransferases (Alcohol Group Acceptor) ,Germ Cells ,030104 developmental biology ,Mutagenesis ,Ethylnitrosourea ,Mutation ,RNA splicing ,Bone Diseases - Abstract
Proper embryonic and postnatal skeletal development require coordination of myriad complex molecular mechanisms. Disruption of these processes, through genetic mutation, contributes to variation in skeletal development. We developed a high-throughput N-ethyl-N-nitrosourea (ENU)-induced saturation mutagenesis skeletal screening approach in mice to identify genes required for proper skeletal development. Here, we report initial results from live-animal X-ray and dual-energy X-ray absorptiometry (DXA) imaging of 27,607 G3 mice from 806 pedigrees, testing the effects of 32,198 coding/splicing mutations in 13,020 genes. A total of 39.7% of all autosomal genes were severely damaged or destroyed by mutations tested twice or more in the homozygous state. Results from our study demonstrate the feasibility of in vivo mutagenesis to identify mouse models of skeletal disease. Furthermore, our study demonstrates how ENU mutagenesis provides opportunities to create and characterize putative hypomorphic mutations in developmentally essential genes. Finally, we present a viable mouse model and case report of recessive skeletal disease caused by mutations in FAM20B. Results from this study, including engineered mouse models, are made publicly available via the online Mutagenetix database. © 2021 American Society for Bone and Mineral Research (ASBMR).
- Published
- 2021
49. Composition of lymphocyte subpopulations in normal and mildly reactive peripheral lymph nodes in cats
- Author
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Daniel Baumgartner, Sandra Groiss, Ilse Schwendenwein, Elisabeth Baszler, Birgitt Wolfesberger, Nicole Weingand, Andrea Fuchs-Baumgartinger, Barbara C. Rütgen, Sabine E. Hammer, and Armin Saalmüller
- Subjects
Pathology ,medicine.medical_specialty ,040301 veterinary sciences ,Immunophenotyping ,Flow cytometry ,0403 veterinary science ,03 medical and health sciences ,Lymphocyte subpopulations ,medicine ,Animals ,Prospective Studies ,Small Animals ,Lymph node ,030304 developmental biology ,0303 health sciences ,CATS ,medicine.diagnostic_test ,business.industry ,Antibodies, Monoclonal ,Feline Lymphoma ,04 agricultural and veterinary sciences ,Flow Cytometry ,Lymphocyte Subsets ,Lymphatic system ,medicine.anatomical_structure ,Cats ,Lymph Nodes ,business ,Peripheral lymph - Abstract
Objectives Flow cytometric (FCM) immunophenotyping of lymphoid tissue aspirates is an available adjunct for feline lymphoma diagnostics. Reference data have only been established for feline peripheral blood. Studies investigating the composition of normal and mildly reactive feline lymph nodes (LNs) are lacking. The aim of this prospective study was to establish reference data for lymphocyte subpopulations in normal and mildly reactive feline peripheral LNs using a standardised multicolour panel of antibodies. Methods Macroscopically inconspicuous mandibular and/or popliteal LNs from 31 adult cats, which were euthanased for reasons other than haematological diseases, were excised and processed within 5 h after death. Multicolour flow cytometry using eight different feline-specific, anti-canine and human cross-reactive monoclonal antibodies used in current diagnostic marker panels was performed after cytological exclusion of pathological states and complemented by lymphocyte clonality testing, histopathology and immunohistochemistry (IHC) to ensure the absence of lymphoid disease. Results Of 31 cats, the immunophenotyping data of 24 individuals could be included as histopathology and clonality testing excluded a pathological condition. Lymphocyte populations showed the following positive antibody reactions: CD18+ 86.3% ± 13.86%, CD3+ 54.81% ± 11.10%, CD5+ 57.39% ± 12.66%, CD21+ 40.42% ± 12.40%, CD79alphacy+ (CD79αcy) 30.41% ± 13.49% and CD14+ 0.75% ± 1.35%. There were 30.88% ± 13.48% CD4+ and 12.91% ± 6.68% CD8+ cells. Cytology revealed a mixed population of mostly lymphoid cells in all samples. The absence of a monoclonal/oligoclonal neoplastic population was confirmed by lymphocyte clonality testing. Histopathology and IHC showed a normal or mildly reactive pattern in all cases. Conclusions and relevance This study establishes FCM immunophenotyping data of lymphocyte populations of normal and mildly reactive feline peripheral LNs. For the first time, anti-CD5, CD4, CD8 and CD21 reference data in normal and mildly reactive feline peripheral LNs are presented. CD18, CD3, CD14 and CD79αcy have been used to establish reference data for the first time in any feline material.
- Published
- 2021
50. First-time application of a PCR-based clonality assay in a large cohort of non-domestic felines
- Author
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Barbara C. Rütgen, Anna Kübber-Heiss, Annika Posautz, Sophia Unterkreuter, Sandra Groiss, and Sabine E. Hammer
- Subjects
Male ,Felidae ,medicine.medical_specialty ,Lymphoma ,040301 veterinary sciences ,Biology ,Polymerase Chain Reaction ,Sensitivity and Specificity ,Cohort Studies ,0403 veterinary science ,03 medical and health sciences ,medicine ,Animals ,Lymphocytes ,030304 developmental biology ,Gene Rearrangement ,0303 health sciences ,CATS ,General Veterinary ,Feline Lymphoma ,Receptors, Antigen, T-Cell, gamma-delta ,04 agricultural and veterinary sciences ,Gold standard (test) ,medicine.disease ,Virology ,T-Cell Receptor Gamma Chain ,Immunoglobulin heavy chain ,Female ,Histopathology ,Primer (molecular biology) - Abstract
Feline lymphoma, one of the most important malignant tumors in domestic cats, is also increasingly diagnosed in non-domestic felines, most notably, African lions (Panthera leo). The gold standard for the diagnosis of lymphoma is histopathological evaluation. As an additional tool, the PCR for antigen receptor gene rearrangement (PARR) has been established. To support the diagnosis on a molecular level, the PCR-based clonality assay is designed to distinguish between reactive and neoplastic lymphocyte populations. In general, PARR primers are used to target complete immunoglobulin heavy chain V-D-J (IGH-VDJ) and T-cell receptor gamma V-J (TRG-VJ) chain gene rearrangements. In this study, we validated the primer sets used in routine diagnostics of domestic cats for the application in non-domestic felines. Clonality testing was used in 41 non-domestic feline species and the results were interpreted in the light of their clinical history and their pathology. In total, clonality could be detected in 8 non-domestic felines (19.4%), including 3 lymphoma cases confirmed by histopathology. These results confirmed the successful application of domestic feline-specific PARR primers in non-domestic feline species. Diagnostic sensitivity and specificity of the clonality assay were 100% and 88%, respectively. Finally, the overall diagnostic accuracy was 89%.
- Published
- 2021
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