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Abstract
A bronchopleural fistula (BPF) can lead to continuous pneumothorax and is rarely reported clinically in dogs. This report describes computed tomographic (CT) findings in two dogs with BPFs and subsequent continuous pneumothoraces that necessitated thoracotomy. Both dogs had a peripheral BPF in the right caudal lung lobe. The fistula in one dog was secondary to a previous foreign body migration, and the fistula in the other was thought to be secondary to dirofilariasis. On both CT examinations, a dilated subsegmental bronchus was seen communicating with the pleural space at the center of a focal, concave region of parenchymal consolidation. Multiplanar reformatting aided in identification and characterization of the BPF. The pneumothoraces resolved after right caudal lobectomy in both dogs. CT has the potential to identify BPFs, such as secondary to foreign body migration or dirofilariasis.
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Affiliation(s)
- Jantra N Suran
- Sections of Radiology (J.S., J.R.) and Surgery (A.L.), Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
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Lo AJ, Holt DE, Brown DC, Schlicksup MD, Orsher RJ, Agnello KA. Treatment of aldosterone-secreting adrenocortical tumors in cats by unilateral adrenalectomy: 10 cases (2002-2012). J Vet Intern Med 2013; 28:137-43. [PMID: 24372771 PMCID: PMC4895543 DOI: 10.1111/jvim.12186] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 07/25/2013] [Accepted: 08/06/2013] [Indexed: 11/28/2022] Open
Abstract
Background Primary hyperaldosteronism (PHA) in cats occurs as a consequence of excessive hormone production by an adrenocortical tumor. Median survival time, association between tumor type and prognosis, and the likelihood that cats require continued medical therapy after surgery have not been systematically evaluated. Objectives To determine the median survival time of cats with PHA treated by unilateral adrenalectomy. To examine if tumor type, anesthesia time, or tumor location (left or right side) affect survival and if affected cats require continued postoperative treatment for persistent hypertension or hypokalemia. Animals Ten client‐owned cats. Methods Retrospective study. Cats were diagnosed with PHA based on clinical signs, increased plasma aldosterone concentration, and advanced imaging. Cats underwent unilateral adrenalectomy. Survival time (days alive after surgery) was determined for each cat. Factors affecting median survival time were investigated, including histopathology, anesthesia time, and location (side) of the tumor. Results Eight of 10 cats survived to discharge from the hospital post adrenalectomy. Overall median survival was 1,297 days (range 2–1,582 days). The only significant factor affecting median survival time was anesthesia time >4 hours. Tumor type and location (side) did not significantly affect median survival time. No cats required continued medical treatment for PHA. Conclusions and Clinical Importance Although PHA in cats is still considered an uncommon condition, it should be considered in middle to older aged cats with hypokalemic polymyopathy and systemic hypertension. Surgical correction by unilateral adrenalectomy is a viable approach to definitive treatment of PHA with no need for continued medical management.
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Affiliation(s)
- A J Lo
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
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Lo AJ, Goldschmidt MH, Aronson LR. Osteomyelitis of the coxofemoral joint due to Mycobacterium species in a feline renal transplant recipient. J Feline Med Surg 2012; 14:919-23. [DOI: 10.1177/1098612x12454983] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A 4-year-old castrated male Russian Blue cat was evaluated for acute right hind limb lameness 18 months after receiving a renal transplant. Radiographs showed a subluxated right femoral head and lysis of the acetabulum and femoral neck. A femoral head and neck ostectomy was performed on the right coxofemoral joint. Histologic evaluation of the right femoral head revealed lesions indicative of a chronic, granulomatous osteomyelitis and periostitis associated with an intralesional Mycobacterium species. However, the cat’s clinical condition declined despite treatment and the owner elected humane euthanasia. All renal transplant recipients receive immunosuppressive therapy to prevent allograft rejection. The non-tuberculous mycobacterial infection of the coxofemoral joint was thought to develop secondary to long-term immunosuppressive treatment. This report illustrates the need to consider these rare opportunistic infections even many months to years following renal transplantation. Early awareness, stringent immunosuppressive drug monitoring and targeted treatment once a diagnosis has been made may be important in the successful management and prevention of mycobacterial infections in this population of patients.
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Affiliation(s)
- Annie J Lo
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael H Goldschmidt
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lillian R Aronson
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Ponthier JL, Schluepen C, Chen W, Lersch RA, Gee SL, Hou VC, Lo AJ, Short SA, Chasis JA, Winkelmann JC, Conboy JG. Fox-2 splicing factor binds to a conserved intron motif to promote inclusion of protein 4.1R alternative exon 16. J Biol Chem 2006; 281:12468-74. [PMID: 16537540 DOI: 10.1074/jbc.m511556200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of protein 4.1R exon 16 (E16) inclusion during erythropoiesis represents a physiologically important splicing switch that increases 4.1R affinity for spectrin and actin. Previous studies showed that negative regulation of E16 splicing is mediated by the binding of heterogeneous nuclear ribonucleoprotein (hnRNP) A/B proteins to silencer elements in the exon and that down-regulation of hnRNP A/B proteins in erythroblasts leads to activation of E16 inclusion. This article demonstrates that positive regulation of E16 splicing can be mediated by Fox-2 or Fox-1, two closely related splicing factors that possess identical RNA recognition motifs. SELEX experiments with human Fox-1 revealed highly selective binding to the hexamer UGCAUG. Both Fox-1 and Fox-2 were able to bind the conserved UGCAUG elements in the proximal intron downstream of E16, and both could activate E16 splicing in HeLa cell co-transfection assays in a UGCAUG-dependent manner. Conversely, knockdown of Fox-2 expression, achieved with two different siRNA sequences resulted in decreased E16 splicing. Moreover, immunoblot experiments demonstrate mouse erythroblasts express Fox-2. These findings suggest that Fox-2 is a physiological activator of E16 splicing in differentiating erythroid cells in vivo. Recent experiments show that UGCAUG is present in the proximal intron sequence of many tissue-specific alternative exons, and we propose that the Fox family of splicing enhancers plays an important role in alternative splicing switches during differentiation in metazoan organisms.
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Affiliation(s)
- Julie L Ponthier
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Krauss SW, Lo AJ, Short SA, Koury MJ, Mohandas N, Chasis JA. Nuclear substructure reorganization during late-stage erythropoiesis is selective and does not involve caspase cleavage of major nuclear substructural proteins. Blood 2005; 106:2200-5. [PMID: 15933051 PMCID: PMC1895142 DOI: 10.1182/blood-2005-04-1357] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Enucleation, a rare feature of mammalian differentiation, occurs in 3 cell types: erythroblasts, lens epithelium, and keratinocytes. Previous investigations suggest that caspase activation functions in lens epithelial and keratinocyte enucleation, as well as in early erythropoiesis encompassing erythroid burst-forming unit (BFU-E) differentiation to proerythroblast. To determine whether caspase activation contributes to later erythropoiesis and whether nuclear substructures other than chromatin reorganize, we analyzed distributions of nuclear subcompartment proteins and assayed for caspase-induced cleavage of subcompartmental target proteins in mouse erythroblasts. We found that patterns of lamin B in the filamentous network interacting with both the nuclear envelope and DNA, nuclear matrix protein NuMA (Nuclear mitotic apparatus), and splicing factors Sm and SC35 persisted during nuclear condensation, consistent with effective transcription of genes expressed late in differentiation. Thus, nuclear reorganization prior to enucleation is selective, allowing maintenance of critical transcriptional processes independent of extensive chromosomal reorganization. Consistent with these data, we found no evidence for caspase-induced cleavage of major nuclear subcompartment proteins during late erythropoiesis, in contrast to what has been observed in early erythropoiesis and in lens epithelial and keratinocyte differentiation. These findings imply that nuclear condensation and extrusion during terminal erythroid differentiation involve novel mechanisms that do not entail major activation of apoptotic machinery.
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Affiliation(s)
- Sharon Wald Krauss
- Life Sciences Division, University of California Lawrence Berkeley National Laboratory, Bldg 74, 1 Cyclotron Rd, Berkeley, CA 94720, USA
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Lee JCM, Gimm JA, Lo AJ, Koury MJ, Krauss SW, Mohandas N, Chasis JA. Mechanism of protein sorting during erythroblast enucleation: role of cytoskeletal connectivity. Blood 2003; 103:1912-9. [PMID: 14563645 DOI: 10.1182/blood-2003-03-0928] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During erythroblast enucleation, nuclei surrounded by plasma membrane separate from erythroblast cytoplasm. A key aspect of this process is sorting of erythroblast plasma membrane components to reticulocytes and expelled nuclei. Although it is known that cytoskeletal elements actin and spectrin partition to reticulocytes, little is understood about molecular mechanisms governing plasma membrane protein sorting. We chose glycophorin A (GPA) as a model integral protein to begin investigating protein-sorting mechanisms. Using immunofluorescence microscopy and Western blotting we found that GPA sorted predominantly to reticulocytes. We hypothesized that the degree of skeletal linkage might control the sorting pattern of transmembrane proteins. To explore this hypothesis, we quantified the extent of GPA association to the cytoskeleton in erythroblasts, young reticulocytes, and mature erythrocytes using fluorescence imaged microdeformation (FIMD) and observed that GPA underwent dramatic reorganization during terminal differentiation. We discovered that GPA was more connected to the membrane cytoskeleton, either directly or indirectly, in erythroblasts and young reticulocytes than in mature cells. We conclude that skeletal protein association can regulate protein sorting during enucleation. Further, we suggest that the enhanced rigidity of reticulocyte membranes observed in earlier investigations results, at least in part, from increased connectivity of GPA with the spectrin-based skeleton.
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Affiliation(s)
- James C-M Lee
- Department of Biological Engineering, University of Missouri-Columbia, USA
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Hou VC, Lersch R, Gee SL, Ponthier JL, Lo AJ, Wu M, Turck CW, Koury M, Krainer AR, Mayeda A, Conboy JG. Decrease in hnRNP A/B expression during erythropoiesis mediates a pre-mRNA splicing switch. EMBO J 2002; 21:6195-204. [PMID: 12426391 PMCID: PMC137214 DOI: 10.1093/emboj/cdf625] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A physiologically important alternative pre-mRNA splicing switch, involving activation of protein 4.1R exon 16 (E16) splicing, is required for the establishment of proper mechanical integrity of the erythrocyte membrane during erythropoiesis. Here we identify a conserved exonic splicing silencer element (CE(16)) in E16 that interacts with hnRNP A/B proteins and plays a role in repression of E16 splicing during early erythropoiesis. Experiments with model pre-mRNAs showed that CE(16) can repress splicing of upstream introns, and that mutagenesis or replacement of CE(16) can relieve this inhibition. An affinity selection assay with biotinylated CE(16) RNA demonstrated specific binding of hnRNP A/B proteins. Depletion of hnRNP A/B proteins from nuclear extract significantly increased E16 inclusion, while repletion with recombinant hnRNP A/B restored E16 silencing. Most importantly, differentiating mouse erythroblasts exhibited a stage-specific activation of the E16 splicing switch in concert with a dramatic and specific down-regulation of hnRNP A/B protein expression. These findings demonstrate that natural developmental changes in hnRNP A/B proteins can effect physiologically important switches in pre-mRNA splicing.
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Affiliation(s)
| | | | | | | | | | - Michael Wu
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
| | - Chris W. Turck
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
| | - Mark Koury
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
| | - Adrian R. Krainer
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
| | - Akila Mayeda
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
| | - John G. Conboy
- Lawrence Berkeley National Laboratory, Life Sciences Division and
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94720, University of California, San Francisco, HHMI, Department of Medicine and Cardiovascular Research Institute, San Francisco, CA 94143, Department of Medicine, Vanderbilt University, Veterans Affairs Medical Centers, Nashville, TN 37232, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 and University of Miami School of Medicine, Department of Biochemistry and Molecular Biology, Miami, FL 33136, USA Corresponding author e-mail:
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