79 results on '"Karl N"'
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2. Phosphatase PHLPP2 regulates the cellular response to metabolic stress through AMPK
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Aditi S. Bapat, Karl N. Krecke, Douglas G. Mashek, Ameeta Kelekar, Michael W. Lopresti, Tingyuan Yang, and Yan Yan
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Cancer Research ,MST1 ,Cell Survival ,Immunology ,Apoptosis ,P70-S6 Kinase 1 ,AMP-Activated Protein Kinases ,Article ,Stress signalling ,Cellular and Molecular Neuroscience ,Protein Domains ,Stress, Physiological ,Cell Line, Tumor ,Phosphoprotein Phosphatases ,Humans ,Phosphorylation ,RNA, Small Interfering ,Protein kinase A ,Protein kinase B ,Protein kinase C ,PHLPP ,QH573-671 ,Kinase ,Chemistry ,Fatty Acids ,AMPK ,Cell Biology ,Cancer metabolism ,Cell biology ,Enzyme Activation ,Glucose ,Cytology ,Oxidation-Reduction ,Protein Binding - Abstract
PHLPP2 is a member of the PHLPP family of phosphatases, known to suppress cell growth by inhibiting proliferation or promoting apoptosis. Oncogenic kinases Akt, S6K, and PKC, and pro-apoptotic kinase Mst1, have been recognized as functional targets of the PHLPP family. However, we observed that, in T-leukemia cells subjected to metabolic stress from glucose limitation, PHLPP2 specifically targets the energy-sensing AMP-activated protein kinase, pAMPK, rather than Akt or S6K. PHLPP2 dephosphorylates pAMPK in several other human cancer cells as well. PHLPP2 and pAMPK interact with each other, and the pleckstrin homology (PH) domain on PHLPP2 is required for their interaction, for dephosphorylating and inactivating AMPK, and for the apoptotic response of the leukemia cells to glucose limitation. Silencing PHLPP2 protein expression prolongs the survival of leukemia cells subjected to severe glucose limitation by promoting a switch to AMPK-mediated fatty acid oxidation for energy generation. Thus, this study reveals a novel role for PHLPP2 in suppressing a survival response mediated through AMPK signaling. Given the multiple ways in which PHLPP phosphatases act to oppose survival signaling in cancers and the pivotal role played by AMPK in redox homeostasis via glucose and fatty acid metabolism, the revelation that AMPK is a target of PHLPP2 could lead to better therapeutics directed both at cancer and at metabolic diseases.
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- 2021
3. Cytoplasmic DNA: sources, sensing, and role in aging and disease
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Stella Victorelli, Nirmalya Dasgupta, Peter D. Adams, Hanna Salmonowicz, João F. Passos, Karl N. Miller, and Tianhui Liu
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Senescence ,Aging ,Cytoplasm ,Mitochondrial DNA ,Innate immune system ,Retroelements ,Endogeny ,Retrotransposon ,Inflammation ,DNA ,Disease ,Biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,medicine ,Animals ,Humans ,medicine.symptom ,Micronucleus, Germline ,Neuroscience ,General Economics, Econometrics and Finance ,Function (biology) - Abstract
Endogenous cytoplasmic DNA (cytoDNA) species are emerging as key mediators of inflammation in diverse physiological and pathological contexts. Although the role of endogenous cytoDNA in innate immune activation is well established, the cytoDNA species themselves are often poorly characterized and difficult to distinguish, and their mechanisms of formation, scope of function and contribution to disease are incompletely understood. Here, we summarize current knowledge in this rapidly progressing field with emphases on similarities and differences between distinct cytoDNAs, their underlying molecular mechanisms of formation and function, interactions between cytoDNA pathways, and therapeutic opportunities in the treatment of age-associated diseases.
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- 2022
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4. Mebendazole’s Conformational Space and its Predicted Binding to Human Heat-Shock Protein 90
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Fabian Freisleben, Karl N. Kirschner, Jasmin Wellbrock, and Walter Fiedler
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Protein Conformation ,General Chemical Engineering ,Mebendazole ,Molecular Conformation ,Crystal structure ,Library and Information Sciences ,Molecular Dynamics Simulation ,Molecular dynamics ,chemistry.chemical_compound ,Adenosine Triphosphate ,Heat shock protein ,medicine ,Humans ,HSP90 Heat-Shock Proteins ,Binding site ,biology ,Chemistry ,General Chemistry ,Tautomer ,Hsp90 ,Computer Science Applications ,biology.protein ,Biophysics ,Adenosine triphosphate ,Protein Binding ,medicine.drug - Abstract
Recent experimental evidence suggest that mebendazole, a popular antiparasitic drug, binds to heat shock protein 90 (Hsp90) and inhibit acute myeloid leukemia cell growth. In this study we use quantum mechanics (QM), molecular similarity and molecular dynamics (MD) calculations to predict possible binding poses of mebendazole to the adenosine triphosphate (ATP) binding site of Hsp90. Extensive conformational searches and minimization of the five tautomers of mebendazole using MP2/aug-cc-pVTZ theory level resulting in 152 minima being identified. Mebendazole-Hsp90 complex models were created using the QM optimized conformations and protein coordinates obtained from experimental crystal structures that were chosen through similarity calculations. Nine different poses were identified from a total of 600 ns of explicit solvent, all-atom MD simulations using two different force fields. All simulations support the hypothesis that mebendazole is able to bind to the ATP binding site of Hsp90.
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- 2022
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5. SMART syndrome: retrospective review of a rare delayed complication of radiation
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Karl N. Krecke, Amy Kunchok, Alejandro A. Rabinstein, Sean J. Pittock, J. D. Bartleson, Mania Hajeb, Tarun D. Singh, and David F. Black
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Adult ,Male ,Pediatrics ,medicine.medical_specialty ,Migraine Disorders ,Temporal lobe ,03 medical and health sciences ,0302 clinical medicine ,Interquartile range ,Humans ,Medicine ,030212 general & internal medicine ,Aged ,Retrospective Studies ,Univariate analysis ,business.industry ,Retrospective cohort study ,Syndrome ,Odds ratio ,Middle Aged ,Magnetic Resonance Imaging ,Stroke ,Neurology ,Cohort ,Etiology ,Female ,Neurology (clinical) ,business ,Complication ,030217 neurology & neurosurgery - Abstract
BACKGROUND SMART (stroke-like migraine attacks after radiation therapy) is a rare, delayed complication of brain radiation. In this study, we wanted to review the spectrum of symptoms, neuroradiological findings, autoimmune status, and outcomes in SMART syndrome patients. METHODS We conducted a retrospective cohort study of all consecutive adult patients (≥18 years) diagnosed with SMART syndrome at Mayo Clinic, Rochester between January 1995 and December 2018. RESULTS We identified 25 unique patients with SMART syndrome and a total of 31 episodes and 15 (60%) patients were male. The median age at onset was 46 (interquartile range [IQR] 43-55) years and the median latency of onset after the initial radiation was 21.6 (IQR 14.4-28.2) years. Magnetic resonance imaging (MRI) showed gyral edema and enhancement in all cases with the temporal (25, 80.6%) and parietal (23, 74.2%) lobes being the most commonly affected. The median follow-up of the patients in our cohort was 10 (IQR 6-32) weeks. On univariate analysis, factors associated with an increased risk of recurrent SMART episodes were female gender (odds ratio [OR] 8.1, 95% confidence interval [95% CI] 1.1-52.6, p = 0.019) and absence of electrographic seizure discharges during initial symptoms (OR 7.4, 95% CI 1.1-45.9, p = 0.032). We could not identify an autoimmune etiology. Longer duration of symptoms (>10 weeks) correlated with an older age (p = 0.049), temporal lobe involvement (p
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- 2020
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6. MOG-IgG1 and co-existence of neuronal autoantibodies
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John J. Chen, Revere P. Kinkel, Sean J. Pittock, Justin Dominick, Jonathan D. Santoro, Kurt M. Sieloff, J. Alfredo Caceres, Amy Kunchok, Andrew McKeon, Karl N. Krecke, Miguel Ruvalcaba, Ian Ferguson, John C. Probasco, Jeremy Timothy, Eoin P. Flanagan, and Brian G. Weinshenker
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Adult ,Adolescent ,Article ,Immunoglobulin G ,Myelin oligodendrocyte glycoprotein ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,immune system diseases ,Humans ,Medicine ,In patient ,Child ,Autoantibodies ,030304 developmental biology ,Autoimmune encephalitis ,0303 health sciences ,biology ,business.industry ,Multiple sclerosis ,Autoantibody ,Syndrome ,medicine.disease ,nervous system ,Neurology ,Child, Preschool ,Immunology ,biology.protein ,Myelin-Oligodendrocyte Glycoprotein ,Neurology (clinical) ,Antibody ,business ,030217 neurology & neurosurgery - Abstract
Background: The presence of co-existent neuronal antibodies (neuronal-IgG) in patients with myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG1) is not yet well understood. Objectives: The aim of this study was to investigate the co-existence of a broad range of neuronal-IgG in MOG-IgG1+ patients. Methods: MOG-IgG1+ patients were tested for 17 neuronal-IgGs in cerebrospinal fluid (CSF) and serum including NMDA-R-IgG, AMPA-R-IgG, GABAB-R-IgG, LGI1-IgG, CASPR2-IgG, GABAA-R-IgG, GAD65-IgG, mGLUR1-IgG, DPPX-IgG, CRMP5-IgG, amphiphysin-IgG, PCA1,2,Tr, and ANNA1,2,3. Clinical and radiological features of MOG-IgG1+ with NMDA-R-IgG in CSF were compared to a control cohort of MOG-IgG1+ patients without NMDA-R-IgG. Results: A total of 376 MOG-IgG1+ patients underwent testing for neuronal-IgGs. Serum testing for neuronal-IgGs (113 adults, 142 children) identified one child with NMDA-R-IgG (0.7%), one child with CASPR2-IgG (0.7%), one adult with LGI1-IgG (0.9%) and one adult with GABAA-R-IgG (0.9%). CSF testing for neuronal-IgGs (97 adults, 169 children) identified seven children (4%) and seven adults (7%) with NMDA-R-IgG, and one adult with GABAA-R-IgG (1%). The MOG-IgG1+/NMDA-R-IgG+ patients had a median age of 17 (range: 2–39) years. Features associated with MOG-IgG1+/NMDA-R-IgG+ included encephalopathy ( p = 0.001), seizures ( p = 0.045), and leptomeningeal enhancement ( p = 0.045). Conclusion: NMDA-R-IgG was the most frequently detected neuronal-IgG to co-exist with MOG-IgG1. MOG-IgG1+/NMDA-R-IgG+ patients most often presented with encephalopathy and seizures. Testing for MOG-IgG1 and NMDA-R-IgG may be warranted in patients with encephalopathy and inflammatory demyelinating syndromes.
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- 2020
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7. Frequency and characteristics of MRI-negative myelitis associated with MOG autoantibodies
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A. Sebastian Lopez-Chiriboga, Elia Sechi, Karl N. Krecke, Brian G. Weinshenker, Amy Kunchok, Eoin P. Flanagan, Divyanshu Dubey, Sean J. Pittock, and Nicholas L. Zalewski
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Pathology ,medicine.medical_specialty ,Mri negative ,Myelitis ,Article ,Myelin oligodendrocyte glycoprotein ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Medicine ,Autoantibodies ,Retrospective Studies ,030304 developmental biology ,Aquaporin 4 ,0303 health sciences ,Neuromyelitis optica ,biology ,business.industry ,Multiple sclerosis ,Neuromyelitis Optica ,Autoantibody ,medicine.disease ,Spinal cord ,Magnetic Resonance Imaging ,Acute Transverse Myelitis ,medicine.anatomical_structure ,Neurology ,biology.protein ,Myelin-Oligodendrocyte Glycoprotein ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Background: Myelitis accompanied by a negative spinal cord MRI may lead to diagnostic uncertainty. Objective and Methods: We retrospectively investigated the frequency of negative spinal cord MRI (performed Results: The initial spinal cord MRI was negative in 7/73 (10%) patients, despite severe acute disability (median EDSS, 7 (range, 4.5–8)); myelitis symptoms/signs were frequent (paraparesis, neurogenic bladder, sensory level, Lhermitte’s phenomenon). Myelitis lesions became overt at follow-up MRI in three patients. Conclusions: A negative spinal cord MRI should not dissuade from MOG-IgG testing in patients with acute/subacute myelitis.
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- 2020
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8. Conformer-Specific Spectroscopy and IR-Induced Isomerization of a Model γ-Peptide: Ac-γ
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Joshua L, Fischer, Karl N, Blodgett, Christopher P, Harrilal, Patrick S, Walsh, Zachary S, Davis, Sunglim, Choi, Soo Hyuk, Choi, and Timothy S, Zwier
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Isomerism ,Spectrophotometry, Infrared ,Molecular Conformation ,Humans ,Peptides ,Amides - Abstract
Single-conformation IR and UV spectroscopy of the prototypical capped γ-peptide Ac-γ
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- 2022
9. Association between paraneoplastic rhombencephalitis and hypertrophic olivary degeneration
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Carrie M. Carr, Divyanshu Dubey, Andrew McKeon, Ajay A. Madhavan, Karl N. Krecke, and Christopher P. Wood
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Adult ,Male ,Cerebellum ,Pathology ,medicine.medical_specialty ,Olivary Nucleus ,White matter ,03 medical and health sciences ,0302 clinical medicine ,Atrophy ,Cerebrospinal fluid ,medicine ,Humans ,business.industry ,Olivary degeneration ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Hyperintensity ,Psychiatry and Mental health ,medicine.anatomical_structure ,Nerve Degeneration ,Encephalitis ,Female ,Surgery ,Cerebellar atrophy ,Neurology (clinical) ,Brainstem ,business ,030217 neurology & neurosurgery ,Brain Stem - Abstract
Hypertrophic olivary degeneration (HOD) is a condition caused by interruption of white matter tracts within the dentato-rubro-olivary pathway (DROP), resulting in inferior olivary T2 hyperintensity and enlargement on MRI. Olivary atrophy may be seen as a sequela of HOD.1 HOD has been described in association with brainstem infarcts, tumours, demyelination and vascular lesions such as cavernous malformations.2 However, HOD can also be seen in the absence of any lesion in the DROP and is sometimes idiopathic.3 Rhombencephalitis refers to inflammation involving the brainstem and/or cerebellum and can rarely be caused by paraneoplastic syndromes. Several neural specific antibodies are classically associated with paraneoplastic rhombencephalitis, including anti-Ma2 and antineuronal nuclear antibody type 2 (ANNA2 or anti-Ri). Kelch-like protein 11 (KLHL11) IgG is another recently described serological biomarker that has a strong association with paraneoplastic rhombencephalitis.4 The tumours frequently associated with paraneoplastic rhombencephalitis include testicular seminoma, breast cancer, small cell lung cancer and gynaecological malignancies. Brain MRI is often normal or shows progressive brainstem and cerebellar atrophy. MRI in these patients can also rarely show brainstem T2 hyperintensity and enhancement. A recently reported KLHL11 rhombencephalitis patient was incidentally noted to have left-sided HOD caused by a dentate lesion.4 However, no clear association between paraneoplastic rhombencephalitis and HOD has been previously suggested, even in comprehensive reviews.5 Here, we report six patients with onconeural antibody-associated paraneoplastic rhombencephalitis who developed HOD. Electronic medical records were queried to identify patients evaluated at our institution from 2005 to 2020 whose serum and/or cerebrospinal fluid demonstrated seropositivity to any of the following autoantibodies: type-1 antineuronal nuclear antibody (ANNA1/anti-Hu), KLHL11, Ma2, ANNA-2 (anti-Ri), Purkinje cell antibody type 1 (PCA-1, anti-Yo), collapsin response mediator 5 (CRMP5 or anti-CV2), amphiphysin and PCA-Tr (DNER). This revealed 177 total patients (KLHL11, n=24; Ma2, n=11; ANNA-1, n=60; ANNA-2, n=14; …
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- 2021
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10. Mebendazole Mediates Proteasomal Degradation of GLI Transcription Factors in Acute Myeloid Leukemia
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Franziska Modemann, Fabian Freisleben, Walter Fiedler, Franziska Brauneck, Carsten Bokemeyer, Jana Muschhammer, Karl N. Kirschner, Alexander Krispien, Hauke Stamm, and Jasmin Wellbrock
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Proteasome Endopeptidase Complex ,QH301-705.5 ,Zinc Finger Protein GLI1 ,Catalysis ,Article ,mebendazole ,Inorganic Chemistry ,Structure-Activity Relationship ,AML ,GLI1 ,GLI2 ,medicine ,Humans ,MBZ ,HSP90 ,Luciferase ,ddc:610 ,Physical and Theoretical Chemistry ,Biology (General) ,Molecular Biology ,Transcription factor ,QD1-999 ,Spectroscopy ,Heat-Shock Proteins ,HSP70 ,ddc:616 ,biology ,Chemistry ,Organic Chemistry ,Myeloid leukemia ,General Medicine ,Hsp90 ,Tubulin Modulators ,Computer Science Applications ,Leukemia, Myeloid, Acute ,Cell culture ,Case-Control Studies ,Proteolysis ,biology.protein ,Cancer research ,Cytarabine ,medicine.drug ,Signal Transduction ,Transcription Factors ,GLI - Abstract
The prognosis of elderly AML patients is still poor due to chemotherapy resistance. The Hedgehog (HH) pathway is important for leukemic transformation because of aberrant activation of GLI transcription factors. MBZ is a well-tolerated anthelmintic that exhibits strong antitumor effects. Herein, we show that MBZ induced strong, dose-dependent anti-leukemic effects on AML cells, including the sensitization of AML cells to chemotherapy with cytarabine. MBZ strongly reduced intracellular protein levels of GLI1/GLI2 transcription factors. Consequently, MBZ reduced the GLI promoter activity as observed in luciferase-based reporter assays in AML cell lines. Further analysis revealed that MBZ mediates its anti-leukemic effects by promoting the proteasomal degradation of GLI transcription factors via inhibition of HSP70/90 chaperone activity. Extensive molecular dynamics simulations were performed on the MBZ-HSP90 complex, showing a stable binding interaction at the ATP binding site. Importantly, two patients with refractory AML were treated with MBZ in an off-label setting and MBZ effectively reduced the GLI signaling activity in a modified plasma inhibitory assay, resulting in a decrease in peripheral blood blast counts in one patient. Our data prove that MBZ is an effective GLI inhibitor that should be evaluated in combination to conventional chemotherapy in the clinical setting.
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- 2021
11. Neuroimaging of Spinal Cord and Cauda Equina Disorders
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Felix E, Diehn and Karl N, Krecke
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Aquaporin 4 ,Cauda Equina ,Spinal Cord ,Humans ,Neuroimaging ,Spinal Cord Neoplasms ,Magnetic Resonance Imaging - Abstract
This article reviews the neuroimaging of disorders of the spinal cord and cauda equina, with a focus on MRI. An anatomic approach is used; diseases of the extradural, intradural-extramedullary, and intramedullary (parenchymal) compartments are considered, and both neoplastic and non-neoplastic conditions are covered. Differentiating imaging features are highlighted.Although T2-hyperintense signal abnormality of the spinal cord can have myriad etiologies, neuroimaging can provide specific diagnoses or considerably narrow the differential diagnosis in many cases. Intradural-extramedullary lesions compressing the spinal cord have a limited differential diagnosis and are usually benign; meningiomas and schwannomas are most common. Extradural lesions can often be specifically diagnosed. Disk herniations are the most commonly encountered mass of the epidural space. Cervical spondylotic myelopathy can cause a characteristic pattern of enhancement, which may be mistaken for an intrinsic myelopathy. A do-not-miss diagnosis of the extradural compartment is idiopathic spinal cord herniation, the appearance of which can overlap with arachnoid cysts and webs. Regarding intrinsic causes of myelopathy, the lesions of multiple sclerosis are characteristically short segment but can be confluent when multiple. Postcontrast MRI can be particularly helpful, including when attempting to differentiate the long-segment myelopathy of neurosarcoidosis and aquaporin-4 (AQP4)-IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD) and when characterizing spinal cord tumors such as primary neoplasms and metastases. Spinal dural arteriovenous fistula is another do-not-miss diagnosis, with characteristic MRI features both precontrast and postcontrast. Tract-specific white matter involvement can be a clue for diseases such as subacute combined degeneration, paraneoplastic myelopathy, and radiation myelitis, whereas gray matter-specific involvement can suggest conditions such as cord infarct, viral myelitis, or myelin oligodendrocyte glycoprotein (MOG)-IgG associated disorder.Knowledge of the neuroimaging findings of the many causes of spinal cord and cauda equina dysfunction is critical for both neurologists and neuroradiologists. A structured approach to lesion compartmental location and imaging feature characterization is recommended.
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- 2021
12. Serum Neurofilament to Magnetic Resonance Imaging Lesion Area Ratio Differentiates Spinal Cord Infarction From Acute Myelitis
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Deena M. Nasr, Sergio Ferrari, Alejandro A. Rabinstein, Salvatore Monaco, Elia Sechi, Eoin P. Flanagan, Sean J. Pittock, Karl N. Krecke, Nicholas L. Zalewski, Andrew McKeon, Serena Zanzoni, Sara Mariotto, and Dean M. Wingerchuk
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Adult ,Male ,Pathology ,medicine.medical_specialty ,Neurofilament ,Myelitis ,myelin oligodendrocyte glycoprotein ,Myelitis, Transverse ,Transverse myelitis ,Myelin oligodendrocyte glycoprotein ,Lesion ,Cohort Studies ,Diagnosis, Differential ,03 medical and health sciences ,transverse myelitis ,0302 clinical medicine ,Neurofilament Proteins ,medicine ,Humans ,030304 developmental biology ,Aged ,Retrospective Studies ,Advanced and Specialized Nursing ,Aged, 80 and over ,Aquaporin 4 ,0303 health sciences ,medicine.diagnostic_test ,biology ,business.industry ,Spinal Cord Ischemia ,Reproducibility of Results ,Magnetic resonance imaging ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Infarction ,Acute Disease ,biology.protein ,Female ,Myelin-Oligodendrocyte Glycoprotein ,Neurology (clinical) ,Spinal cord infarction ,Immunotherapy ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,030217 neurology & neurosurgery - Abstract
Background and Purpose: The diagnosis of spontaneous spinal cord infarction (SCI) is limited by the lack of diagnostic biomarkers and MRI features that often overlap with those of other myelopathies, especially acute myelitis. We investigated whether the ratio between serum neurofilament light chain levels and MRI T2-lesion area (neurofilament light chain/area ratio—NAR) differentiates SCI from acute myelitis of similar severity. Methods: We retrospectively identified Mayo Clinic patients (January 1, 2000–December 31, 2019) with (1) SCI, (2) AQP4 (aquaporin 4)-IgG or MOG (myelin oligodendrocyte glycoprotein)-IgG-associated myelitis at disease clinical presentation, or (3) idiopathic transverse myelitis from a previously identified population-based cohort of patients seronegative for AQP4-IgG and MOG-IgG. Serum neurofilament light chain levels (pg/mL) were assessed at the Verona University (SIMOA, Quanterix) in a blinded fashion on available stored samples obtained ≤3 months from myelopathy presentation. For each patient, the largest spinal cord lesion area (mm 2 ) was manually outlined by 2 independent raters on sagittal T2-weighted MRI images, and the mean value was used to determine NAR (pg/[mL·mm 2 ]). Results: Forty-eight patients were included SCI, 20 (definite, 11; probable, 6; possible, 3); acute myelitis, 28 (AQP4-IgG-associated, 17; MOG-IgG-associated, 5; idiopathic transverse myelitis, 6). The median expanded disability status scale score (range) at myelopathy nadir were 7.75 (2–8.5) and 5.5 (2–8), respectively. Serum neurofilament light chain levels (median [range] pg/mL) in patients with SCI (188 [14.3–2793.4]) were significantly higher compared with patients with AQP4-IgG-associated myelitis (37 [0.8–6942.9]), MOG-IgG-associated myelitis (45.8 [4–283.8]), and idiopathic transverse myelitis (15.6 [0.9–217.8]); P =0.01. NAR showed the highest accuracy for identification of SCI versus acute myelitis with values ≥0.35 pg/(mL·mm 2 ) yielding 86% specificity and 95% sensitivity (area under the curve=0.93). The positive and negative likelihood ratios were 6.67 and 0.06, respectively. NAR remained independently associated with SCI after adjusting for age, gender, immunotherapy before sampling, and days from myelopathy symptoms onset to sampling ( P =0.0007). Conclusions: NAR is a novel and promising clinical biomarker for differentiation of SCI from acute myelitis.
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- 2021
13. Duodenal mucosal mitochondrial gene expression is associated with delayed gastric emptying in diabetic gastroenteropathy
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Mayank Sharma, Karl N. Miller, Alfonso Eirin, Daniel R. O'Brien, João F. Passos, Adil E. Bharucha, Susrutha Puthanmadhom Narayanan, Peter D. Adams, and Tamas Ordog
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Adult ,Male ,0301 basic medicine ,Translation ,Mitochondrial DNA ,Gastroparesis ,Duodenum ,Gene Expression ,Mitochondrion ,Biology ,DNA, Mitochondrial ,Oxidative Phosphorylation ,Diabetes Complications ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Microscopy, Electron, Transmission ,Humans ,RNA, Messenger ,NRF1 ,Intestinal Mucosa ,Promoter Regions, Genetic ,Gene ,Gastric emptying ,Diabetes ,fungi ,Gastroenterology ,Promoter ,General Medicine ,Middle Aged ,Phenotype ,Molecular biology ,Mitochondria ,MicroRNAs ,Genes, Mitochondrial ,030104 developmental biology ,Gastric Emptying ,Mitochondrial biogenesis ,Case-Control Studies ,030220 oncology & carcinogenesis ,Medicine ,Female ,Research Article - Abstract
Hindered by a limited understanding of the mechanisms responsible for diabetic gastroenteropathy (DGE), management is symptomatic. We investigated the duodenal mucosal expression of protein-coding genes and microRNAs (miRNA) in DGE and related them to clinical features. The diabetic phenotype, gastric emptying, mRNA, and miRNA expression and ultrastructure of duodenal mucosal biopsies were compared in 39 DGE patients and 21 controls. Among 3175 differentially expressed genes (FDR < 0.05), several mitochondrial DNA–encoded (mtDNA-encoded) genes (12 of 13 protein coding genes involved in oxidative phosphorylation [OXPHOS], both rRNAs and 9 of 22 transfer RNAs) were downregulated; conversely, nuclear DNA–encoded (nDNA-encoded) mitochondrial genes (OXPHOS) were upregulated in DGE. The promoters of differentially expressed genes were enriched in motifs for transcription factors (e.g., NRF1), which regulate mitochondrial biogenesis. Seventeen of 30 differentially expressed miRNAs targeted differentially expressed mitochondrial genes. Mitochondrial density was reduced and correlated with expression of 9 mtDNA OXPHOS genes. Uncovered by principal component (PC) analysis of 70 OXPHOS genes, PC1 was associated with neuropathy (P = 0.01) and delayed gastric emptying (P < 0.05). In DGE, mtDNA- and nDNA-encoded mitochondrial genes are reduced and increased — associated with reduced mitochondrial density, neuropathy, and delayed gastric emptying — and correlated with cognate miRNAs. These findings suggest that mitochondrial disturbances may contribute to delayed gastric emptying in DGE.
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- 2021
14. Comparison of MRI Lesion Evolution in Different Central Nervous System Demyelinating Disorders
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A. Sebastian Lopez-Chiriboga, Brian G. Weinshenker, Padraig P. Morris, Sean J. Pittock, Elia Sechi, Tammy M. Greenwood, Amy Kunchok, Claudia F. Lucchinetti, Karl N. Krecke, Salvatore Monaco, Adam Nguyen, John J. Chen, Eoin P. Flanagan, Steven A. Messina, Marina Buciuc, Jan Mendelt Tillema, Stephanie B. Syc-Mazurek, B. Mark Keegan, Nicholas L. Zalewski, and James P. Fryer
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Adult ,Male ,medicine.medical_specialty ,Multiple Sclerosis ,Adolescent ,lesion evolution ,Myelitis ,Myelin oligodendrocyte glycoprotein ,Lesion ,Young Adult ,medicine ,Humans ,Demyelinating Disorder ,Child ,Aged ,Retrospective Studies ,Neuromyelitis optica ,biology ,Index Lesion ,business.industry ,Multiple sclerosis ,Brain ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,CNS demyelinating diseases ,Aquaporin 4 ,comparison ,Child, Preschool ,biology.protein ,Disease Progression ,Female ,Neurology (clinical) ,Radiology ,medicine.symptom ,business ,MRI ,Demyelinating Diseases ,Research Article - Abstract
Background and ObjectiveThere are few studies comparing lesion evolution across different CNS demyelinating diseases, yet knowledge of this may be important for diagnosis and understanding differences in disease pathogenesis. We sought to compare MRI T2 lesion evolution in myelin oligodendrocyte glycoprotein immunoglobulin G (IgG)–associated disorder (MOGAD), aquaporin 4 IgG–positive neuromyelitis optica spectrum disorder (AQP4-IgG-NMOSD), and multiple sclerosis (MS).MethodsIn this descriptive study, we retrospectively identified Mayo Clinic patients with MOGAD, AQP4-IgG-NMOSD, or MS and (1) brain or myelitis attack; (2) available attack MRI within 6 weeks; and (3) follow-up MRI beyond 6 months without interval relapses in that region. Two neurologists identified the symptomatic or largest T2 lesion for each patient (index lesion). MRIs were then independently reviewed by 2 neuroradiologists blinded to diagnosis to determine resolution of T2 lesions by consensus. The index T2 lesion area was manually outlined acutely and at follow-up to assess variation in size.ResultsWe included 156 patients (MOGAD, 38; AQP4-IgG-NMOSD, 51; MS, 67) with 172 attacks (brain, 81; myelitis, 91). The age (median [range]) differed between MOGAD (25 [2–74]), AQP4-IgG-NMOSD (53 [10–78]), and MS (37 [16–61]) (p < 0.01) and female sex predominated in the AQP4-IgG-NMOSD (41/51 [80%]) and MS (51/67 [76%]) groups but not among those with MOGAD (17/38 [45%]). Complete resolution of the index T2 lesion was more frequent in MOGAD (brain, 13/18 [72%]; spine, 22/28 [79%]) than AQP4-IgG-NMOSD (brain, 3/21 [14%]; spine, 0/34 [0%]) and MS (brain, 7/42 [17%]; spine, 0/29 [0%]) (p < 0.001). Resolution of all T2 lesions occurred most often in MOGAD (brain, 7/18 [39%]; spine, 22/28 [79%]) than AQP4-IgG-NMOSD (brain, 2/21 [10%]; spine, 0/34 [0%]) and MS (brain, 2/42 [5%]; spine, 0/29 [0%]) (p < 0.01). There was a larger median (range) reduction in T2 lesion area in mm2 on follow-up axial brain MRI with MOGAD (213 [55–873]) than AQP4-IgG-NMOSD (104 [0.7–597]) (p = 0.02) and MS (36 [0–506]) (p < 0.001) and the reductions in size on sagittal spine MRI follow-up in MOGAD (262 [0–888]) and AQP4-IgG-NMOSD (309 [0–1885]) were similar (p = 0.4) and greater than in MS (23 [0–152]) (p < 0.001).DiscussionThe MRI T2 lesions in MOGAD resolve completely more often than in AQP4-IgG-NMOSD and MS. This has implications for diagnosis, monitoring disease activity, and clinical trial design, while also providing insight into pathogenesis of CNS demyelinating diseases.
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- 2020
15. Diffuse Calvarial Hyperostosis in Patients with Spontaneous Intracranial Hypotension
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Felix E. Diehn, Patrick H. Luetmer, Derek R. Johnson, Jared T. Verdoorn, Vance T. Lehman, Karl N. Krecke, Jeremy K. Cutsforth-Gregory, and Carrie M. Carr
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Adult ,Male ,Hyperostosis ,medicine.medical_specialty ,Intracranial Hypotension ,Context (language use) ,Craniofacial Abnormalities ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,In patient ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Skull ,medicine.anatomical_structure ,Calvarial hyperostosis ,030220 oncology & carcinogenesis ,Surgery ,Female ,Neurology (clinical) ,Radiology ,business ,Tomography, X-Ray Computed ,Myelography ,030217 neurology & neurosurgery - Abstract
Background Diagnosis of spontaneous intracranial hypotension (SIH) may be delayed due to nonspecific symptoms and variable imaging findings. Cases of hyperostosis in children who are overshunted, a process that may be physiologically analogous to adults with SIH, have been reported by others and observed in our practice. The purpose of this retrospective study was to assess the frequency and pattern of calvarial hyperostosis in patients with SIH. Methods We retrospectively reviewed computed tomography and magnetic resonance imaging examinations from consecutive patients who underwent myelography for the evaluation of SIH to assess for the presence of generalized calvarial thickening or development of a secondary layer of bone. Patients with typical benign hyperostosis frontalis were excluded. Patient demographics and clinical factors were evaluated for association with hyperostosis. Results Among 285 patients with SIH, 40 (14.0%) demonstrated diffuse calvarial hyperostosis on imaging. Most of these patients (32/40; 80.0%) demonstrated a distinct circumferentially layered appearance to the skull, whereas 8 of 40 (20.0%) had generalized calvarial thickening without layering. Conclusions Diffuse calvarial hyperostosis, particularly the concentrically layered form that we term “layer cake skull,” is a relatively common imaging feature in patients with SIH. In the appropriate clinical context, this finding will allow the possibility of SIH to be raised based on computed tomography imaging, which is otherwise of limited utility in the initial diagnosis of this condition.
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- 2020
16. Mitochondria-to-nucleus retrograde signaling drives formation of cytoplasmic chromatin and inflammation in senescence
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Karl N. Miller, Patrick Krüger, Colin Nixon, Kathryn Gilroy, João F. Passos, Arantxa Perez-Garcia, Xue Lei, Maria Grazia Vizioli, Anthony B. Lagnado, Diana Jurk, Christos Kiourtis, William C. Clark, Neil Robertson, Nirmalya Dasgupta, Shelley L. Berger, Tianhui Liu, Thomas G. Bird, Zhixun Dou, and Peter D. Adams
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Senescence ,Male ,Cytoplasm ,MAP Kinase Signaling System ,Oxidative phosphorylation ,Mitochondrion ,Biology ,medicine.disease_cause ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Genetics ,medicine ,Animals ,Humans ,Nuclear protein ,Cellular Senescence ,030304 developmental biology ,Cell Nucleus ,Inflammation ,0303 health sciences ,Gene Expression Regulation, Developmental ,Chromatin ,Cell biology ,Mitochondria ,Histone Deacetylase Inhibitors ,Mice, Inbred C57BL ,Cytosol ,030220 oncology & carcinogenesis ,Retrograde signaling ,Signal transduction ,Reactive Oxygen Species ,Tumor Suppressor p53-Binding Protein 1 ,Oxidative stress ,Developmental Biology ,Signal Transduction - Abstract
Cellular senescence is a potent tumor suppressor mechanism but also contributes to aging and aging-related diseases. Senescence is characterized by a stable cell cycle arrest and a complex proinflammatory secretome, termed the senescence-associated secretory phenotype (SASP). We recently discovered that cytoplasmic chromatin fragments (CCFs), extruded from the nucleus of senescent cells, trigger the SASP through activation of the innate immunity cytosolic DNA sensing cGAS–STING pathway. However, the upstream signaling events that instigate CCF formation remain unknown. Here, we show that dysfunctional mitochondria, linked to down-regulation of nuclear-encoded mitochondrial oxidative phosphorylation genes, trigger a ROS–JNK retrograde signaling pathway that drives CCF formation and hence the SASP. JNK links to 53BP1, a nuclear protein that negatively regulates DNA double-strand break (DSB) end resection and CCF formation. Importantly, we show that low-dose HDAC inhibitors restore expression of most nuclear-encoded mitochondrial oxidative phosphorylation genes, improve mitochondrial function, and suppress CCFs and the SASP in senescent cells. In mouse models, HDAC inhibitors also suppress oxidative stress, CCF, inflammation, and tissue damage caused by senescence-inducing irradiation and/or acetaminophen-induced mitochondria dysfunction. Overall, our findings outline an extended mitochondria-to-nucleus retrograde signaling pathway that initiates formation of CCF during senescence and is a potential target for drug-based interventions to inhibit the proaging SASP.
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- 2020
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17. Implementing a Radiology Residency Quality Curriculum to Develop Physician Leaders and Increase Value for Patients
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Karl N. Krecke, Julie L Cravath, Tara L. Henrichsen, Ashley S Rosier, and A. Nicholas Kurup
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medicine.medical_specialty ,Quality management ,media_common.quotation_subject ,education ,MEDLINE ,Experiential learning ,Patient safety ,ComputingMilieux_COMPUTERSANDEDUCATION ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Quality (business) ,Program Development ,Curriculum ,media_common ,medicine.diagnostic_test ,business.industry ,Internship and Residency ,Interventional radiology ,Quality Improvement ,United States ,Leadership ,Workflow ,Education, Medical, Graduate ,Radiology ,Patient Safety ,business - Abstract
Diagnostic and interventional radiology residency programs must educate trainees on quality and patient safety topics to meet board requirements and prepare residents to become effective physician leaders. A quality curriculum should encompass process improvement methodology as well as instruction about crucial patient safety subjects. The authors have developed a standardized and structured approach to fulfill this need using didactic and experiential learning. The educational format includes short lectures, peer-to-peer instruction, and self-study, with the value of presented information reinforced by physician leaders and process improvement specialists. Equally important is a structured experience in departmental quality improvement wherein trainees learn the collaborative nature of effective durable process change in areas of interest to them. This curriculum is implemented during the 3rd year of radiology residency to leverage residents' knowledge and experience with radiology workflows and proximity to the American Board of Radiology Core Exam. Feedback from educators and trainees as well as objective examination data support this approach. This article shares guidance and lessons learned from the authors' radiology residency educational efforts and offers a framework for successful implementation of a comprehensive quality curriculum at any residency training program. This curriculum serves the dual purpose of developing skilled future physician leaders and promoting value for patients. ©RSNA, 2020.
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- 2020
18. Polyclonal lymphocytic infiltrate with arachnoiditis resulting from intrathecal stem cell transplantation
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Karl N. Krecke, John C. Benson, Aditya Raghunathan, Ajay A. Madhavan, Dong K Kim, Dan Summerfield, and Christopher H. Hunt
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Male ,Pathology ,medicine.medical_specialty ,medicine.medical_treatment ,Glial cell proliferation ,Thoracic Vertebrae ,030218 nuclear medicine & medical imaging ,Lesion ,03 medical and health sciences ,0302 clinical medicine ,Medical Tourism ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Neoplastic Diseases ,Aged ,Lumbar Vertebrae ,business.industry ,Cauda equina ,General Medicine ,Stem-cell therapy ,medicine.disease ,Magnetic Resonance Imaging ,Transplantation ,medicine.anatomical_structure ,Arachnoiditis ,Neurology (clinical) ,Thecal sac ,medicine.symptom ,Stem cell ,business ,030217 neurology & neurosurgery ,Stem Cell Transplantation - Abstract
Stem cell treatment outside of studied and approved medical indications can have unforeseen adverse consequences. Here, we present a 74-year-old male that underwent such therapy. The patient presented to our institution with progressive lower extremity weakness and urinary incontinence. He had previously undergone intrathecal stem cell therapy in Moscow, Russia for weakness and fatigue. Magnetic resonance imaging of his thoracic and lumbar spine showed marked enlargement of the cauda equina nerve roots and abnormal mass-like soft tissue involving the thoracolumbar thecal sac. Surgical biopsy of the intrathecal soft tissue showed polyclonal lymphocytic and glial cell proliferation. The patient’s symptoms did not improve with medical treatment or radiation, and he is currently under observation after multidisciplinary evaluation. Our patient’s experience illustrates one of the potential risks of “stem cell tourism” and exemplifies the imaging and histopathologic features of this rare entity. We also compare our patient’s treatment with other similar examples of stem cell treatments in our institution and others. These have had a wide spectrum of results. In some instances, intrathecal stem cells have caused abnormal imaging findings without any associated patient symptoms. In extreme examples, however, stem cell treatments have resulted in central nervous system neoplasms. Our patient’s lesion is quite unique, with only one similar lesion having been previously published.
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- 2020
19. Spinal cord infarction: Clinical and imaging insights from the periprocedural setting
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Eoin P. Flanagan, Nicholas L. Zalewski, Robert D. Brown, Derrick A. Doolittle, Karl N. Krecke, Alejandro A. Rabinstein, Brian G. Weinshenker, and Eelco F. M. Wijdicks
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Diagnosis, Differential ,03 medical and health sciences ,Postoperative Complications ,0302 clinical medicine ,medicine ,Humans ,030212 general & internal medicine ,Embolization ,Intraoperative Complications ,Perioperative Period ,Aged ,Retrospective Studies ,Aged, 80 and over ,Spinal Cord Ischemia ,business.industry ,Cauda equina ,Middle Aged ,Vascular surgery ,medicine.disease ,Magnetic Resonance Imaging ,Cardiac surgery ,medicine.anatomical_structure ,Spinal Cord ,Neurology ,Infarction ,Cardiothoracic surgery ,Spinal decompression ,Vascular myelopathy ,Nerve block ,Female ,Neurology (clinical) ,Radiology ,business ,Biomarkers ,030217 neurology & neurosurgery ,Follow-Up Studies - Abstract
Objective Describe the range of procedures associated with spinal cord infarction (SCI) as a complication of a medical/surgical procedure and define clinical and imaging characteristics that could be applied to help diagnose spontaneous SCI, where the diagnosis is often less secure. Methods We used an institution-based search tool to identify patients evaluated at Mayo Clinic, Rochester, MN from 1997 to 2016 with a periprocedural SCI. We performed a descriptive analysis of clinical features, MRI and other laboratory findings, and outcome. Results Seventy-five patients were identified with SCI related to an invasive or non-invasive surgery including: aortic aneurysm repair (49%); other aortic surgery (15%); and a variety of other procedures (e.g., cardiac surgery, spinal decompression, epidural injection, angiography, nerve block, embolization, other vascular surgery, thoracic surgery) (36%). Deficits were severe (66% para/quadriplegia) and maximal at first post-procedural evaluation in 61 patients (81%). Impaired dorsal column function was common on initial examination. Imaging features included classic findings of owl eyes or anterior pencil sign on MRI (70%), but several other T2-hyperintensity patterns were also seen. Gadolinium enhancement of the SCI and/or cauda equina was also common when assessed. Six patients (10%) had an initial normal MRI despite a severe deficit. Conclusions Procedures associated with SCI are many, and this complication does not exclusively occur following aortic surgery. The clinical and radiologic findings that we describe with periprocedural SCI may be used in future studies to help distinguish spontaneous SCI from alternate causes of acute myelopathy.
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- 2018
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20. Diagnostic criteria for chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS)
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Yong Guo, Sean J. Pittock, Karl N. Krecke, Jan Debruyne, W. Oliver Tobin, Claudia F. Lucchinetti, Divyanshu Dubey, Jay Mandrekar, B. Mark Keegan, and Joseph E. Parisi
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Adult ,Male ,Pathology ,medicine.medical_specialty ,Cerebellum ,White matter lesion ,Gadolinium ,030218 nuclear medicine & medical imaging ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Neuroimaging ,Adrenal Cortex Hormones ,Humans ,Medicine ,Age of Onset ,Neuroinflammation ,Aged ,Retrospective Studies ,Inflammation ,Chronic lymphocytic inflammation ,medicine.diagnostic_test ,business.industry ,ADRENAL CORTICOSTEROIDS ,Magnetic resonance imaging ,Syndrome ,Middle Aged ,Magnetic Resonance Imaging ,Pons ,medicine.anatomical_structure ,Immunology ,Encephalitis ,Female ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a central nervous system inflammatory syndrome predominantly affecting the brainstem, cerebellum, and spinal cord. Following its initial description, the salient features of CLIPPERS have been confirmed and expanded upon, but the lack of formalized diagnostic criteria has led to reports of patients with dissimilar features purported to have CLIPPERS. We evaluated clinical, radiological and pathological features of patients referred for suspected CLIPPERS and propose diagnostic criteria to discriminate CLIPPERS from non-CLIPPERS aetiologies. Thirty-five patients were evaluated for suspected CLIPPERS. Clinical and neuroimaging data were reviewed by three neurologists to confirm CLIPPERS by consensus agreement. Neuroimaging and neuropathology were reviewed by experienced neuroradiologists and neuropathologists, respectively, both of whom were blinded to the clinical data. CLIPPERS was diagnosed in 23 patients (18 male and five female) and 12 patients had a non-CLIPPERS diagnosis. CLIPPERS patients' median age of onset was 58 years (interquartile range, 24-72) and were followed a median of 44 months (interquartile range 38-63). Non-CLIPPERS patients' median age of onset was 52 years (interquartile range, 39-59) and were followed a median of 27 months (interquartile range, 14-47). Clinical symptoms of gait ataxia, diplopia, cognitive impairment, and facial paraesthesia did not discriminate CLIPPERS from non-CLIPPERS. Marked clinical and radiological corticosteroid responsiveness was observed in CLIPPERS (23/23), and clinical worsening occurred in all 12 CLIPPERS cases when corticosteroids were discontinued. Corticosteroid responsiveness was common but not universal in non-CLIPPERS [clinical improvement (8/12); radiological improvement (2/12); clinical worsening on discontinuation (3/8)]. CLIPPERS patients had brainstem predominant perivascular gadolinium enhancing lesions on magnetic resonance imaging that were discriminated from non-CLIPPERS by: homogenous gadolinium enhancing nodules3 mm in diameter without ring-enhancement or mass effect, and homogenous T2 signal abnormality not significantly exceeding the T1 enhancement. Brain neuropathology on 14 CLIPPERS cases demonstrated marked CD3-positive T-lymphocyte, mild B-lymphocyte and moderate macrophage infiltrates, with perivascular predominance as well as diffuse parenchymal infiltration (14/14), present in meninges, white and grey matter, associated with variable tissue destruction, astrogliosis and secondary myelin loss. Clinical, radiological and pathological feature define CLIPPERS syndrome and are differentiated from non-CLIPPERS aetiologies by neuroradiological and neuropathological findings.
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- 2017
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21. Cochlear Implant Electrode Localization Using an Ultra-High Resolution Scan Mode on Conventional 64-Slice and New Generation 192-Slice Multi-Detector Computed Tomography
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John I. Lane, Karl N. Krecke, Michael R. Bruesewitz, Robert J. Witte, Matthew L. Carlson, Cynthia H. McCollough, Josh Grimes, Kelly K. Koeller, Felix E. Diehn, and Shuai Leng
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medicine.medical_specialty ,Scanner ,Image quality ,medicine.medical_treatment ,Ring Artifact ,Streak ,03 medical and health sciences ,0302 clinical medicine ,Cochlear implant ,Temporal bone ,medicine ,Humans ,Medical physics ,Radionuclide Imaging ,030223 otorhinolaryngology ,Artifact (error) ,business.industry ,Temporal Bone ,Cochlear Implantation ,Sensory Systems ,Cochlea ,Electrodes, Implanted ,Cochlear Implants ,Otorhinolaryngology ,Electrode ,Neurology (clinical) ,Tomography, X-Ray Computed ,business ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
HYPOTHESIS A new generation 192-slice multi-detector computed tomography (MDCT) clinical scanner provides enhanced image quality and superior electrode localization over conventional MDCT. BACKGROUND Currently, accurate and reliable cochlear implant electrode localization using conventional MDCT scanners remains elusive. METHODS Eight fresh-frozen cadaveric temporal bones were implanted with full-length cochlear implant electrodes. Specimens were subsequently scanned with conventional 64-slice and new generation 192-slice MDCT scanners utilizing ultra-high resolution modes. Additionally, all specimens were scanned with micro-CT to provide a reference criterion for electrode position. Images were reconstructed according to routine temporal bone clinical protocols. Three neuroradiologists, blinded to scanner type, reviewed images independently to assess resolution of individual electrodes, scalar localization, and severity of image artifact. RESULTS Serving as the reference standard, micro-CT identified scalar crossover in one specimen; imaging of all remaining cochleae demonstrated complete scala tympani insertions. The 192-slice MDCT scanner exhibited improved resolution of individual electrodes (p
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- 2017
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22. Glial fibrillary acidic protein IgG related myelitis: characterisation and comparison with aquaporin-4-IgG myelitis
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Nicholas L. Zalewski, Allen J. Aksamit, P. Pearse Morris, Sean J. Pittock, Evan A. Jolliffe, Brian G. Weinshenker, Elia Sechi, Karl N. Krecke, Anastasia Zekeridou, Andrew McKeon, Jiraporn Jitprapaikulsan, Dean M. Wingerchuk, Timothy J. Kaufmann, Eoin P. Flanagan, and Shannon R. Hinson
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Adult ,Male ,Pathology ,medicine.medical_specialty ,Adolescent ,Myelitis ,Young Adult ,03 medical and health sciences ,Myelopathy ,Myelin ,0302 clinical medicine ,Cerebrospinal fluid ,Glial Fibrillary Acidic Protein ,medicine ,Humans ,Aged ,Autoantibodies ,Aquaporin 4 ,First episode ,Glial fibrillary acidic protein ,biology ,business.industry ,Multiple sclerosis ,Neuromyelitis Optica ,Brain ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Psychiatry and Mental health ,Exact test ,medicine.anatomical_structure ,Spinal Cord ,Case-Control Studies ,Immunoglobulin G ,biology.protein ,Female ,Surgery ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
IgG directed against the α-isoform of glial fibrillary acidic protein (GFAP-IgG) predicts a distinct corticosteroid-responsive meningoencephalomyelitis termed autoimmune GFAP astrocytopathy, when detected on cerebrospinal fluid (CSF).1 Optic disc oedema and tremor are common accompaniments. The MRI hallmark is a striking linear perivascular enhancement radially oriented around the ventricles (radial enhancement), while the myelitis component is generally associated with a longitudinally extensive T2 lesion on spinal cord MRI, similar to that typically encountered in aquaporin-4-IgG (AQP4-IgG) related myelitis.1–3 We compared the clinical, laboratory and MRI features of GFAP-IgG and AQP4-IgG related myelitis. ### Patient ascertainment We retrospectively identified GFAP-IgG seropositive patients seen at the Mayo Clinic ( 1 January 2000 to 31 December 2017). Inclusion criteria were as follows: (1) serum/CSF demonstrating GFAP pattern by indirect immunofluorescence with GFAPα specificity confirmed by cell-based assay, as previously described;1 (2) first myelitis episode; (3) serum sample negative for myelin oligodendrocyte glycoprotein-IgG (MOG-IgG) and AQP4-IgG using previously described methodology4 5; (4) adequate clinical data available. Nine patients with GFAP-IgG myelitis were included in a prior report.1 Two patients with dual positivity in serum for AQP4-IgG and GFAP-IgG were excluded. Medical records were reviewed and compared with 41 patients from a previously identified cohort of AQP4-IgG seropositive patients at the first episode of clinical myelitis who tested negative for GFAP-IgG (41 tested) and MOG-IgG (13 tested).5 Improvement was defined as subjective improvement reported by the patient with objective improvement confirmed by the physician. ### Neuroimaging All available MRI sequences obtained within 4 months of myelitis onset were reviewed by one neurology investigator (ES/EPF) and one neuroradiologist (TJK/KNK/PPM) as described previously.5 Consensus was achieved in situations of disagreement. ### Statistical analysis Wilcoxon rank-sum test or χ2/Fisher’s exact test was used as appropriate for comparison (JMP 8.0 software). Fifty-four patients with myelitis were included: GFAP-IgG positive, …
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- 2018
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23. Prevalence of Asymptomatic Middle Cranial Fossa Floor Pits and Encephaloceles on MR Imaging
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Karl N. Krecke, John C. Benson, Jamie J. Van Gompel, John I. Lane, and Jennifer R. Geske
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Adult ,Male ,medicine.medical_specialty ,Middle cranial fossa ,Asymptomatic ,030218 nuclear medicine & medical imaging ,Temporal lobe ,Encephalocele ,Cohort Studies ,03 medical and health sciences ,Epilepsy ,0302 clinical medicine ,Prevalence ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Retrospective Studies ,Incidental Findings ,Cranial Fossa, Middle ,medicine.diagnostic_test ,business.industry ,Adult Brain ,Magnetic resonance imaging ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Temporal Lobe ,medicine.anatomical_structure ,Laterality ,Female ,Neurology (clinical) ,Radiology ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
BACKGROUND AND PURPOSE: Temporal lobe encephaloceles are increasingly identified and treated as epileptogenic foci. However, there is relatively scant research on the prevalence of asymptomatic encephaloceles. This study set out to describe the frequency of incidental temporal lobe encephaloceles and middle cranial fossa pits. MATERIALS AND METHODS: A retrospective review was completed of high-resolution (≤0.5-mm section thickness) axial T2WI for internal auditory canal protocol imaging. The presence and laterality of middle cranial fossa pits (small bony defects containing CSF) and encephaloceles (brain parenchyma protrusion through osseous defects with or without bony remodeling) were recorded. Electronic medical records of patients with encephaloceles were searched for a history of seizure. RESULTS: A total of 203 patients were included in the final cohort; 106 (52.2%) women. Forty-five (22.2%) patients had middle cranial fossa pits: 14 (31.1%) unilateral on the right, 17 (37.8%) unilateral on the left, and 14 (31.1%) bilateral. Ten (5.0%) patients had ≥1 encephalocele, none of whom had a documented history of seizure in the electronic medical record. No significant difference was noted in the frequency of pits or encephaloceles based on sex (P = .332 and P = .383, respectively) or age (P = .497 and P = .914, respectively). CONCLUSIONS: Incidental middle cranial fossa pits are common findings, and their prevalence is not related to age or sex. Temporal lobe encephaloceles, though rarer, also exist occasionally among asymptomatic patients. Such findings have diagnostic implications for encephaloceles identified during imaging work-up for epilepsy.
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- 2019
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24. Does area postrema syndrome occur in myelin oligodendrocyte glycoprotein-IgG-associated disorders (MOGAD)?
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A. Sebastian Lopez-Chiriboga, Karl N. Krecke, Brian G. Weinshenker, Eoin P. Flanagan, John J. Chen, Amy Kunchok, Sean J. Pittock, and Jiraporn Jitprapaikulsan
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Adult ,Male ,Pathology ,medicine.medical_specialty ,Vomiting ,Myelitis ,Demyelinating Autoimmune Diseases, CNS ,Myelin oligodendrocyte glycoprotein ,Hiccup ,03 medical and health sciences ,Myelin ,0302 clinical medicine ,medicine ,Humans ,Optic neuritis ,030212 general & internal medicine ,Child ,Neuromyelitis optica ,biology ,business.industry ,Nausea ,Syndrome ,medicine.disease ,Oligodendrocyte ,medicine.anatomical_structure ,Area Postrema ,Immunoglobulin G ,Acute disseminated encephalomyelitis ,biology.protein ,Biomarker (medicine) ,Female ,Myelin-Oligodendrocyte Glycoprotein ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Myelin oligodendrocyte glycoprotein-IgG is a biomarker associated with CNS demyelinating diseases.1,2 MOGAD and aquaporin-4-IgG–positive neuromyelitis optica spectrum disorder (AQP4-IgG + NMOSD) have overlapping clinical features including optic neuritis and myelitis. However, there are several clinical and radiologic distinguishing features of MOGAD including lack of female predominance, higher incidence of acute disseminated encephalomyelitis (ADEM), higher proportion of bilateral optic neuritis, and T2-signal confined to gray matter and conus involvement in myelitis.1,3,4
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- 2019
25. Molecular and Functional Networks Linked to Sarcopenia Prevention by Caloric Restriction in Rhesus Monkeys
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Christine W. Lary, Tyler M. DeMuth, Ricki J. Colman, Laura Vaughan, Matthew W. Conklin, Josef P. Clark, Mark E. Berres, Karl N. Miller, Rozalyn M. Anderson, Kevin W. Eliceiri, Grace E. Gustafson, T. Mark Beasley, and Timothy W. Rhoads
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Adult ,Male ,medicine.medical_specialty ,Sarcopenia ,Histology ,Biology ,Pathology and Forensic Medicine ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Lipid droplet ,medicine ,Animals ,Humans ,030304 developmental biology ,Caloric Restriction ,0303 health sciences ,Skeletal muscle ,Cell Biology ,Metabolism ,medicine.disease ,Phenotype ,Macaca mulatta ,Proteostasis ,Endocrinology ,medicine.anatomical_structure ,Molecular Medicine ,Reprogramming ,030217 neurology & neurosurgery ,Function (biology) - Abstract
Caloric restriction (CR) improves survival in nonhuman primates and delays the onset of age-related morbidities including sarcopenia, which is characterized by the age-related loss of muscle mass and function. A shift in metabolism anticipates the onset of muscle-aging phenotypes in nonhuman primates, suggesting a potential role for metabolism in the protective effects of CR. Here, we show that CR induced profound changes in muscle composition and the cellular metabolic environment. Bioinformatic analysis linked these adaptations to proteostasis, RNA processing, and lipid synthetic pathways. At the tissue level, CR maintained contractile content and attenuated age-related metabolic shifts among individual fiber types with higher mitochondrial activity, altered redox metabolism, and smaller lipid droplet size. Biometric and metabolic rate data confirm preserved metabolic efficiency in CR animals that correlated with the attenuation of age-related muscle mass and physical activity. These data suggest that CR-induced reprogramming of metabolism plays a role in delayed aging of skeletal muscle in rhesus monkeys.
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- 2019
26. Prevalence of Spontaneous Asymptomatic Facial Nerve Canal Meningoceles: A Retrospective Review
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John I. Lane, John C. Benson, J. Van Gompel, Jennifer R. Geske, Matthew L. Carlson, Jacob K. Dey, and Karl N. Krecke
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Fossa ,Asymptomatic ,Meningocele ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Geniculate ,Temporal bone ,medicine ,Prevalence ,Humans ,Radiology, Nuclear Medicine and imaging ,Intracranial Hypotension ,Head & Neck ,Retrospective Studies ,medicine.diagnostic_test ,biology ,business.industry ,Temporal Bone ,Magnetic resonance imaging ,Anatomy ,biology.organism_classification ,Facial nerve ,Magnetic Resonance Imaging ,Neurology (clinical) ,Geniculate ganglion ,medicine.symptom ,Facial Nerve Diseases ,business ,030217 neurology & neurosurgery - Abstract
BACKGROUND AND PURPOSE: The prevalence of patent facial nerve canals and meningoceles along the facial nerve course is unknown. This study aimed to assess the frequency of such findings in asymptomatic patients. MATERIALS AND METHODS: A retrospective review was completed of patients with high-resolution MR imaging of the temporal bone whose clinical presentations were unrelated to facial nerve pathology. Facial nerve canals were assessed for the presence of fluid along each segment and meningoceles within either the labyrinthine segment (fluid-filled distention, ≥1.0-mm diameter) or geniculate ganglion fossa (fluid-filled distention, ≥2.0-mm diameter). If a meningocele was noted, images were assessed for signs of CSF leak. RESULTS: Of 204 patients, 36 (17.6%) had fluid in the labyrinthine segment of the facial nerve canal and 40 (19.6%) had fluid in the geniculate ganglion fossa. Five (2.5%) had meningoceles of the geniculate ganglion fossa; no meningoceles of the labyrinthine segment of the canal were observed. No significant difference was observed in the ages of patients with fluid in the labyrinthine segment of the canal or geniculate ganglion compared with those without fluid (P = .177 and P = .896, respectively). Of the patients with a meningocele, one had a partially empty sella and none had imaging evidence of CSF leak or intracranial hypotension. CONCLUSIONS: Fluid within the labyrinthine and geniculate segments of the facial nerve canal is relatively common. Geniculate ganglion meningoceles are also observed, though less frequently. Such findings should be considered of little clinical importance without radiologic evidence of CSF otorrhea, meningitis, or facial nerve palsy.
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- 2019
27. Ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorders
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Padraig P. Morris, Brian G. Weinshenker, Eoin P. Flanagan, Neeraj Kumar, Dean M. Wingerchuk, Timothy J. Kaufmann, Claudia F. Lucchinetti, Karl N. Krecke, Sean J. Pittock, Nicholas L. Zalewski, and Yong Guo
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Male ,Pathology ,medicine.medical_specialty ,Multiple Sclerosis ,Population ,Myelitis ,Context (language use) ,Spinal Cord Diseases ,030218 nuclear medicine & medical imaging ,Diagnosis, Differential ,03 medical and health sciences ,Myelopathy ,0302 clinical medicine ,medicine ,Humans ,education ,Aquaporin 4 ,Radioisotopes ,education.field_of_study ,Neuromyelitis optica ,business.industry ,Multiple sclerosis ,Neuromyelitis Optica ,Cranial nerves ,medicine.disease ,Spinal cord ,Magnetic Resonance Imaging ,Psychiatry and Mental health ,medicine.anatomical_structure ,Female ,Surgery ,Neurology (clinical) ,Radiology ,business ,030217 neurology & neurosurgery - Abstract
Objective We assessed the frequency and characteristics of ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorder (NMOSD) myelitis and myelitis of other cause. Methods We reviewed spinal cord MRIs for ring-enhancing lesions from 284 aquaporin-4 (AQP4)-IgG seropositive patients at Mayo Clinic from 1996 to 2014. Inclusion criteria were as follows: (1) AQP4-IgG seropositivity, (2) myelitis attack and (3) MRI spinal cord demonstrating ring-enhancement. We identified two groups of control patients with: (1) longitudinally extensive myelopathy of other cause (n=66) and (2) myelitis in the context of a concurrent or subsequent diagnosis of multiple sclerosis (MS) from a population-based cohort (n=30). Results Ring-enhancement was detected in 50 of 156 (32%) myelitis episodes in 41 patients (83% single; 17% multiple attacks). Ring-enhancement was noted on sagittal and axial images in 36 of 43 (84%) ring enhancing myelitis episodes and extended a median of two vertebral segments (range, 1–12); in 21 of 48 (44%) ring enhancing myelitis episodes, the ring extended greater than or equal to three vertebrae. Ring-enhancement was accompanied by longitudinally extensive (greater than or equal to three vertebral segments) T2-hyperintensity in 44 of 50 (88%) ring enhancing myelitis episodes. One case of a spinal cord biopsy during ring-enhancing myelitis revealed tissue vacuolation and loss of AQP4 immunoreactivity with preserved axons. The clinical characteristics of ring-enhancing myelitis episodes did not differ from non-ring-enhancing episodes. Ring-enhancing spinal cord lesions were more common in NMOSD than other causes of longitudinally extensive myelopathy (50/156 (32%) vs 0/66 (0%); p≤0.001) but did not differ between NMOSD and MS (50/156 (32%) vs 6/30 (20%); p=0.20). Conclusions Spinal cord ring-enhancement accompanies one-third of NMOSD myelitis episodes and distinguishes NMOSD from other causes of longitudinally extensive myelopathies but not from MS.
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- 2016
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28. Selective targeting of NAMPT by KPT-9274 in acute myeloid leukemia
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Amy Lehman, James S. Blachly, Bonnie K. Harrington, Virginia M. Goettl, Katie Williams, Deepa Sampath, Alice S. Mims, Nicole Grieselhuber, Karl N. Kirschner, Shaneice Mitchell, William Senapedis, Rosa Lapalombella, Pu Zhang, Justin T. Breitbach, Shelley Orwick, Yerdanose Asemelash, Shuai Dong, Sally E. Henderson, Karilyn Larkin, John C. Byrd, Matthew Cannon, Vinay K. Puduvalli, Pankaj Sharma, Erkan Baloglu, Tzung Huei Lai, and Larry Beaver
- Subjects
0301 basic medicine ,Myeloid ,Nicotinamide phosphoribosyltransferase ,Aminopyridines ,Apoptosis ,HL-60 Cells ,Mice, SCID ,Biology ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Mice, Inbred NOD ,hemic and lymphatic diseases ,Cell Line, Tumor ,medicine ,Cytotoxic T cell ,Animals ,Humans ,Enzyme Inhibitors ,Nicotinamide Phosphoribosyltransferase ,Acrylamides ,Myeloid Neoplasia ,Myeloid leukemia ,Hematology ,medicine.disease ,Xenograft Model Antitumor Assays ,Haematopoiesis ,Leukemia ,Leukemia, Myeloid, Acute ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,030220 oncology & carcinogenesis ,Cancer research ,Cytokines ,NAD+ kinase ,K562 Cells ,K562 cells - Abstract
Treatment options for acute myeloid leukemia (AML) remain extremely limited and associated with significant toxicity. Nicotinamide phosphoribosyltransferase (NAMPT) is involved in the generation of NAD+ and a potential therapeutic target in AML. We evaluated the effect of KPT-9274, a p21-activated kinase 4/NAMPT inhibitor that possesses a unique NAMPT-binding profile based on in silico modeling compared with earlier compounds pursued against this target. KPT-9274 elicited loss of mitochondrial respiration and glycolysis and induced apoptosis in AML subtypes independent of mutations and genomic abnormalities. These actions occurred mainly through the depletion of NAD+, whereas genetic knockdown of p21-activated kinase 4 did not induce cytotoxicity in AML cell lines or influence the cytotoxic effect of KPT-9274. KPT-9274 exposure reduced colony formation, increased blast differentiation, and diminished the frequency of leukemia-initiating cells from primary AML samples; KPT-9274 was minimally cytotoxic toward normal hematopoietic or immune cells. In addition, KPT-9274 improved overall survival in vivo in 2 different mouse models of AML and reduced tumor development in a patient-derived xenograft model of AML. Overall, KPT-9274 exhibited broad preclinical activity across a variety of AML subtypes and warrants further investigation as a potential therapeutic agent for AML.
- Published
- 2018
29. Plastic in the Brain: Delayed Recognition of Progressive Unilateral Hemispheric Lesions
- Author
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Ali, Daneshmand, Karl N, Krecke, and Eelco F M, Wijdicks
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Endovascular Procedures ,Humans ,Female ,Intracranial Aneurysm ,Stents ,Aneurysm, Ruptured ,Middle Aged ,Foreign Bodies ,Embolization, Therapeutic ,Plastics - Abstract
Flow diverters are increasingly used to treat complex ruptured intracranial aneurysms. Most complications are ischemic and seen early after placement.We present a patient with 3 year duration of neurologic symptoms and seizures as a result of lesions associated with a inflammatory response to embolized polymer coating.Over a period of 3 years MRI abnormalities were noted with substantial gadolinium enhancement of the stent but with resolution after corticosteroids.Polymer embolization associated with a flow diverter may cause fluctuating unilateral hemisheric lesions and become symptomatic. Inflammatory response to a foreign body (polymer strands) can be succesfully treated with corticosteroids.
- Published
- 2018
30. Reply: A case of CLIPPERS challenging the new diagnostic criteria
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Karl N. Krecke, Yong Guo, W. Oliver Tobin, and B. Mark Keegan
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Inflammation ,medicine.medical_specialty ,business.industry ,MEDLINE ,03 medical and health sciences ,0302 clinical medicine ,Pons ,medicine ,Humans ,Steroids ,030212 general & internal medicine ,Neurology (clinical) ,Intensive care medicine ,business ,030217 neurology & neurosurgery - Published
- 2017
31. Structural analysis of human glycoprotein butyrylcholinesterase using atomistic molecular dynamics: The importance of glycosylation site ASN241
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Austen Bernardi, Karl N. Kirschner, Roland Faller, and Silman, Israel
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0301 basic medicine ,Glycosylation ,Glycobiology ,lcsh:Medicine ,Molecular Dynamics ,Toxicology ,Pathology and Laboratory Medicine ,Biochemistry ,chemistry.chemical_compound ,Molecular dynamics ,Computational Chemistry ,Biochemical Simulations ,Medicine and Health Sciences ,Post-Translational Modification ,lcsh:Science ,Butyrylcholinesterase ,chemistry.chemical_classification ,Multidisciplinary ,biology ,Hydrolysis ,Physics ,Chemical Reactions ,Structure and function ,Chemistry ,Physical Sciences ,ddc:540 ,Research Article ,Glycan ,Biophysical Simulations ,General Science & Technology ,Toxic Agents ,Biophysics ,Geometry ,Molecular Dynamics Simulation ,03 medical and health sciences ,Humans ,Glycoproteins ,030102 biochemistry & molecular biology ,lcsh:R ,Active site ,Biology and Life Sciences ,Computational Biology ,Proteins ,Nerve Agent Hydrolysis ,carbohydrates (lipids) ,030104 developmental biology ,chemistry ,Dihedral Angles ,biology.protein ,lcsh:Q ,Generic health relevance ,Glycoprotein ,Mathematics - Abstract
Human butyrylcholinesterase (BChE) is a glycoprotein capable of bioscavenging toxic compounds such as organophosphorus (OP) nerve agents. For commercial production of BChE, it is practical to synthesize BChE in non-human expression systems, such as plants or animals. However, the glycosylation profile in these systems is significantly different from the human glycosylation profile, which could result in changes in BChE's structure and function. From our investigation, we found that the glycan attached to ASN241 is both structurally and functionally important due to its close proximity to the BChE tetramerization domain and the active site gorge. To investigate the effects of populating glycosylation site ASN241, monomeric human BChE glycoforms were simulated with and without site ASN241 glycosylated. Our simulations indicate that the structure and function of human BChE are significantly affected by the absence of glycan 241.
- Published
- 2017
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32. GSK3β Regulates Brain Energy Metabolism
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Stephen A. Martin, Kevin W. Eliceiri, Karl N. Miller, T. Mark Beasley, Luigi Puglielli, Josef P. Clark, Rozalyn M. Anderson, Dylan C. Souder, and Abdul Kader Sagar
- Subjects
0301 basic medicine ,Male ,Hippocampus ,Hippocampal formation ,PC12 Cells ,General Biochemistry, Genetics and Molecular Biology ,Article ,03 medical and health sciences ,Mice ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Protein Kinase Inhibitors ,Serine/threonine-specific protein kinase ,Neurons ,Glycogen Synthase Kinase 3 beta ,Chemistry ,Protein Stability ,Brain ,Metabolism ,NAD ,Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ,3. Good health ,Cell biology ,Mitochondria ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,Neuron ,NAD+ kinase ,Protein stabilization ,Energy Metabolism ,Neuroglia ,Nuclear localization sequence - Abstract
SUMMARY GSK3β is a serine threonine kinase implicated in the progression of Alzheimer’s disease. Although the role of GSK3β in growth and pathology has been extensively studied, little is known about the metabolic consequences of GSK3β manipulation, particularly in the brain. Here, we show that GSK3β regulates mitochondrial energy metabolism in human H4 neuroglioma cells and rat PC12-derived neuronal cells and that inhibition of GSK3β in mice in vivo alters metabolism in the hippocampus in a region-specific manner. We demonstrate that GSK3β inhibition increases mitochondrial respiration and membrane potential and alters NAD(P)H metabolism. These metabolic effects are associated with increased PGC-1α protein stabilization, enhanced nuclear localization, and increased transcriptional co-activation. In mice treated with the GSK3β inhibitor lithium carbonate, changes in hippocampal energy metabolism are linked to increased PGC-1α. These data highlight a metabolic role for brain GSK3β and suggest that the GSK3β/PGC-1α axis may be important in neuronal metabolic integrity., In Brief Martin et al. demonstrate that GSK3β is a regulator of energy metabolism in the brain. They show that GSK3β inhibition stimulates mitochondrial regulator PGC-1α and leads to activation of mitochondrial and redox pathways in glia, in neurons in culture, and in the hippocampus in mice in vivo.
- Published
- 2017
33. The ‘Molecule of the Month’ Website—An Extraordinary Chemistry Educational Resource Online for over 20 Years
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Simon Cotton, Henry Rzepa, Karl N. Harrison, and Paul W May
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Engineering ,Pharmaceutical Science ,Nanotechnology ,Chemistry education ,01 natural sciences ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,World Wide Web ,Online chemistry resources ,lcsh:Organic chemistry ,Drug Discovery ,Humans ,online chemistry resources ,Chemistry (relationship) ,Physical and Theoretical Chemistry ,Internet ,chemistry education ,chemical databases ,010405 organic chemistry ,business.industry ,05 social sciences ,Organic Chemistry ,050301 education ,0104 chemical sciences ,Chemistry ,Chemistry (miscellaneous) ,Educational resources ,Molecular Medicine ,Virtual learning environment ,business ,0503 education ,Databases, Chemical - Abstract
The Molecule of the Month website (http://www.chm.bris.ac.uk/motm/motm.htm) is an educational resource that is celebrating its 20th anniversary. Here we reflect on its pioneering role in promoting new technology for visualizing and presenting chemical information on the web, as well as its achievements, as a free educational resource, both as a teaching aid and as a multi-user, multi-author learning platform. We discuss the legal aspects of such sites, as well as issues around how to make the content permanent. Finally, we look forward to how such sites may evolve in the future.
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- 2017
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34. Pilot Study of Radiation Dose Reduction for Pediatric Head CT in Evaluation of Ventricular Size
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Karl N. Krecke, Joel G. Fletcher, Lifeng Yu, David R. DeLone, Cynthia H. McCollough, Laurence J. Eckel, S. Gabriel, and Patrick H. Luetmer
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Male ,medicine.medical_specialty ,Image quality ,Pilot Projects ,Iterative reconstruction ,Radiation Dosage ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,In patient ,Cerebral Ventriculography ,Child ,Ventricular size ,Csf shunt ,business.industry ,Radiation dose ,medicine.disease ,Hydrocephalus ,Radiographic Image Interpretation, Computer-Assisted ,Female ,Patient Safety ,Neurology (clinical) ,Radiology ,Tomography, X-Ray Computed ,business ,Nuclear medicine ,Algorithms ,Shunt (electrical) - Abstract
BACKGROUND AND PURPOSE: CT is a ubiquitous, efficient, and cost-effective method to evaluate pediatric ventricular size, particularly in patients with CSF shunt diversion who often need emergent imaging. We therefore sought to determine the minimum dose output or CT dose index required to produce clinically acceptable examinations. MATERIALS AND METHODS: Using a validated noise insertion method and CT projection data from 22 patients, standard pediatric head CT images were reconstructed with weighted filtered back-projection and sinogram-affirmed iterative reconstruction corresponding to routine, 25%, and 10% dose. Reconstructed images were then evaluated by 3 neuroradiologists (blinded to dose and reconstruction method) for ventricular size, diagnostic confidence, image quality, evidence of hemorrhage, and shunt tip location, and compared with the reference standard. RESULTS: There was no significant difference in the ventricular size ranking, and the sensitivity for moderate to severe hydrocephalus was 100%. There was no significant difference between the full-dose level and the ventricular size rankings at the 25% or the 10% dose level for either reconstruction kernel (P > .979). Diagnostic confidence was maintained across doses and kernel. Hemorrhage was more difficult to identify as image quality degraded as dose decreased but was still seen in a majority of cases. Shunts were identified by all readers across all doses and reconstruction methods. CONCLUSIONS: CT images having dose reductions of 90% relative to routine head CT examinations provide acceptable image quality to address the specific clinical task of evaluating ventricular size.
- Published
- 2014
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35. Clinical, Radiologic, and Prognostic Features of Myelitis Associated With Myelin Oligodendrocyte Glycoprotein Autoantibody
- Author
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Elie Naddaf, Avi Gadoth, Brian G. Weinshenker, Jiraporn Jitprapaikulsan, Eoin P. Flanagan, A. Sebastian Lopez-Chiriboga, Kevin Messacar, Padraig P. Morris, Sean J. Pittock, Nicholas L. Zalewski, Marc C. Patterson, Kenneth L. Tyler, Andrew McKeon, B. Mark Keegan, Claudia F. Lucchinetti, Divyanshu Dubey, John C. Chen, Jan Mendelt Tillema, Eslam Shosha, Karl N. Krecke, Elia Sechi, and James P. Fryer
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Encephalomyelitis ,Myelitis ,Myelitis, Transverse ,Transverse myelitis ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Optic neuritis ,030212 general & internal medicine ,Child ,Original Investigation ,Aged ,Autoantibodies ,medicine.diagnostic_test ,business.industry ,Multiple sclerosis ,Encephalomyelitis, Acute Disseminated ,Neuromyelitis Optica ,Magnetic resonance imaging ,Middle Aged ,Prognosis ,medicine.disease ,Acute flaccid myelitis ,nervous system diseases ,Child, Preschool ,Immunoglobulin G ,Acute disseminated encephalomyelitis ,Female ,Myelin-Oligodendrocyte Glycoprotein ,Neurology (clinical) ,Radiology ,Neoplasm Recurrence, Local ,business ,030217 neurology & neurosurgery - Abstract
Importance Recognizing the characteristics of myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) myelitis is essential for early accurate diagnosis and treatment. Objective To evaluate the clinical, radiologic, and prognostic features of MOG-IgG myelitis and compare with myelitis with aquaporin-4–IgG (AQP4-IgG) and multiple sclerosis (MS). Design, Setting, and Participants We retrospectively identified 199 MOG-IgG–positive Mayo Clinic patients from January 1, 2000, through December 31, 2017, through our neuroimmunology laboratory. Fifty-four patients met inclusion criteria of (1) clinical myelitis; (2) MOG-IgG positivity; and (3) medical records available. We excluded 145 patients without documented myelitis. Myelitis of AQP4-IgG (n = 46) and MS (n = 26) were used for comparison. Main Outcomes and Measures Outcome variables included modified Rankin score and need for gait aid. A neuroradiologist analyzed spine magnetic resonance imaging of patients with MOG-IgG and control patients blinded to diagnosis. Results Of 54 included patients with MOG-IgG myelitis, the median age was 25 years (range, 3-73 years) and 24 were women (44%). Isolated transverse myelitis was the initial manifestation in 29 patients (54%), and 10 (19%) were initially diagnosed as having viral/postviral acute flaccid myelitis. Cerebrospinal fluid–elevated oligoclonal bands occurred in 1 of 38 (3%). At final follow-up (median, 24 months; range, 2-120 months), 32 patients (59%) had developed 1 or more relapses of optic neuritis (n = 31); transverse myelitis (n = 7); or acute disseminated encephalomyelitis (n = 1). Clinical features favoring MOG-IgG myelitis vs AQP4-IgG or MS myelitis included prodromal symptoms and concurrent acute disseminated encephalomyelitis. Magnetic resonance imaging features favoring MOG-IgG over AQP4-IgG or MS myelitis were T2-signal abnormality confined to gray matter (sagittal line and axial H sign) and lack of enhancement. Longitudinally extensive T2 lesions were of similar frequency in MOG-IgG and AQP4-IgG myelitis (37 of 47 [79%] vs 28 of 34 [82%];P = .52) but not found in MS. Multiple spinal cord lesions and conus involvement were more frequent with MOG-IgG than AQP4-IgG but not different from MS. Wheelchair dependence at myelitis nadir occurred in one-third of patients with MOG-IgG and AQP4-IgG but never with MS, although patients with MOG-IgG myelitis recovered better than those with AQP4-IgG. Conclusions and Relevance Myelitis is an early manifestation of MOG-IgG–related disease and may have a clinical phenotype of acute flaccid myelitis. We identified a variety of clinical and magnetic resonance imaging features that may help clinicians identify those at risk in whom MOG-IgG should be tested.
- Published
- 2019
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36. Characteristics of Spontaneous Spinal Cord Infarction and Proposed Diagnostic Criteria
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Eelco F. M. Wijdicks, Jonathan M. Morris, Karl N. Krecke, Allen J. Aksamit, Giuseppe Lanzino, Brian G. Weinshenker, J. D. Bartleson, Alejandro A. Rabinstein, Timothy J. Kaufmann, Nicholas L. Zalewski, Robert D. Brown, Melissa M. Blessing, and Eoin P. Flanagan
- Subjects
Male ,medicine.medical_specialty ,Infarction ,Spinal Cord Diseases ,Transverse myelitis ,03 medical and health sciences ,Myelopathy ,0302 clinical medicine ,Interquartile range ,medicine ,Humans ,030212 general & internal medicine ,Aged ,Original Investigation ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,Sensory loss ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Hyperintensity ,Practice Guidelines as Topic ,Etiology ,Female ,Neurology (clinical) ,Radiology ,business ,030217 neurology & neurosurgery - Abstract
Importance Spinal cord infarction (SCI) is often disabling, and the diagnosis can be challenging without an inciting event (eg, aortic surgery). Patients with a spontaneous SCI are often misdiagnosed as having transverse myelitis. Diagnostic criteria for SCI are lacking, hindering clinical care and research. Objective To describe the characteristics of spontaneous SCI and propose diagnostic criteria. Design, Setting, and Participants An institution-based search tool was used to identify patients evaluated at Mayo Clinic, Rochester, Minnesota, from January 1997 to December 2017 with a spontaneous SCI. Patients provided written consent to use their records for research. Participants were 18 years and older with a diagnosis of spontaneous SCI (n = 133), and controls were selected from a database of alternative myelopathy etiologies for validation of the proposed diagnostic criteria (n = 280). Main Outcomes and Measures A descriptive analysis of SCI was performed and used to propose diagnostic criteria, and the criteria were validated. Results Of 133 included patients with a spontaneous SCI, the median (interquartile range) age at presentation was 60 (52-69) years, and 101 (76%) had vascular risk factors. Rapid onset of severe deficits reaching nadir within 12 hours was typical (102 [77%]); some had a stuttering decline (31 [23%]). Sensory loss occurred in 126 patients (95%), selectively affecting pain/temperature in 49 (39%). Initial magnetic resonance imaging (MRI) spine results were normal in 30 patients (24%). Characteristic MRI T2-hyperintense patterns included owl eyes (82 [65%]) and pencil-like hyperintensity (50 [40%]); gadolinium enhancement (37 of 96 [39%]) was often linear and located in the anterior gray matter. Confirmatory MRI findings included diffusion-weighted imaging/apparent diffusion coefficient restriction (19 of 29 [67%]), adjacent dissection/occlusion (16 of 82 [20%]), and vertebral body infarction (11 [9%]). Cerebrospinal fluid showed mild inflammation in 7 of 89 patients (8%). Diagnostic criteria was proposed for definite, probable, and possible SCI of periprocedural and spontaneous onset. In the validation cohort (n = 280), 9 patients (3%) met criteria for possible SCI, and none met criteria for probable SCI. Conclusions and Relevance This large series of spontaneous SCIs provides clinical, laboratory, and MRI clues to SCI diagnosis. The diagnostic criteria proposed here will aid clinicians in making the correct diagnosis and ideally improve future care for patients with SCI. The validation of these criteria supports their utility in the evaluation of acute myelopathy.
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- 2019
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37. Stroke-Like Migraine Attacks after Radiation Therapy (SMART) Syndrome Is Not Always Completely Reversible: A Case Series
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E. P. Lindell, J. D. Bartleson, David F. Black, Daniel H. Lachance, G. A. Worrell, Jonathan M. Morris, and Karl N. Krecke
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Adult ,Male ,medicine.medical_specialty ,Migraine Disorders ,medicine.medical_treatment ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Radiation Injuries ,Cognitive impairment ,Stroke ,Radiotherapy ,Brain Neoplasms ,business.industry ,Remission Induction ,Brain ,Recovery of Function ,Syndrome ,Middle Aged ,Prognosis ,medicine.disease ,Magnetic Resonance Imaging ,Mr imaging ,Surgery ,Radiation therapy ,Treatment Outcome ,Hemiparesis ,Migraine ,Brain Injuries ,Female ,Neurology (clinical) ,Radiology ,medicine.symptom ,Headaches ,business - Abstract
SUMMARY: We retrospectively reviewed clinical and imaging findings in 11 patients with stroke-like migraine attacks after radiation therapy (SMART) syndrome to better understand this disorder previously thought to be reversible. Six men and 5 women had complex bouts of neurologic impairment beginning, on average, 20 years after cerebral irradiation. All had characteristic, unilateral gyriform enhancement on MR imaging that developed within 2–7 days and typically resolved in 2–5 weeks. Unlike prior reports, 45% had incomplete neurologic recovery manifesting as dysphasia, cognitive impairment, or hemiparesis. The remaining 55% recovered completely over an average of 2 months. Three of 11 patients developed cortical laminar necrosis. Brain biopsies in 4 of 11 did not demonstrate a specific pathologic substrate. These additional 11 patients contribute to the understanding of variability in stroke-like migraine attacks after radiation therapy syndrome, which often but not uniformly manifests with headaches and seizures, demonstrates a typical evolution of imaging findings, and may result in permanent neurologic and imaging sequelae.
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- 2013
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38. The futures of agriculture
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Stauber, Karl N.
- Published
- 1994
39. Improving Patient Flow Utilizing a Collaborative Learning Model
- Author
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Laura C, Tibor, Stacy R, Schultz, Julie L, Cravath, Russell R, Rein, and Karl N, Krecke
- Subjects
Patient Care Team ,Inservice Training ,Quality Assurance, Health Care ,Radiology Department, Hospital ,Minnesota ,Process Assessment, Health Care ,Humans ,Cooperative Behavior ,Efficiency, Organizational ,Quality Improvement ,Workflow - Abstract
This initiative utilized a collaborative learning approach to increase knowledge and experience in process improvement and systems thinking while targeting improved patient flow in seven radiology modalities. Teams showed improvements in their project metrics and collectively streamlined the flow for 530 patients per day by improving patient lead time, wait time, and first case on-time start rates. In a post-project survey of 50 project team members, 82% stated they had more effective solutions as a result of the process improvement methodology, 84% stated they will be able to utilize the process improvement tools again in the future, and 98% would recommend participating in another project to a colleague.
- Published
- 2016
40. Usefulness of repeat review of head magnetic resonance images during presurgical epilepsy conferences
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Katherine C. Nickels, Amy L. Kotsenas, Daniel L. Kenney, Robert E. Watson, Elaine C. Wirrell, Lily C. Wong-Kisiel, Kristen M. Kelly-Williams, Karl N. Krecke, Elson L. So, and Robert J. Witte
- Subjects
Surgical resection ,Male ,medicine.medical_specialty ,Drug Resistant Epilepsy ,Clinical Decision-Making ,03 medical and health sciences ,Epilepsy ,0302 clinical medicine ,Preoperative Care ,Radiologists ,medicine ,Humans ,Epilepsy surgery ,030212 general & internal medicine ,Neurologists ,Retrospective Studies ,medicine.diagnostic_test ,Temporal lobectomy ,business.industry ,Brain ,Magnetic resonance imaging ,Resective surgery ,medicine.disease ,Magnetic Resonance Imaging ,Surgery ,Neurology ,Female ,Neurology (clinical) ,business ,030217 neurology & neurosurgery ,Follow-Up Studies - Abstract
Surgical epilepsy conferences are an important part of the process of determining whether a patient is a candidate for resective epilepsy surgery. At these conferences, repeat review ( re-review ) of the magnetic resonance images (MRIs) of the patient's head often occurs. This study assessed how often radiologic re-review at a presurgical epilepsy conference resulted in a changed interpretation of the head MRI. Charts were reviewed for 239 patients who had been presented at presurgical epilepsy conferences between 2008 and 2012. Of the 233 patients whose MRIs were re-reviewed, resective surgery was performed in 94 patients (40.3%). Forty-one patients (17.6%) had a previously undiagnosed finding, and 18 of the 41 (43.9%) underwent resective surgery. For 4 of the 41 patients (9.8%) with a previously undiagnosed pertinent finding, re-review detected abnormalities that were not amenable to surgical resection (autoimmunity or significant bilateral pathology).
- Published
- 2016
41. Highly specific radiographic marker predates clinical diagnosis in progressive supranuclear palsy
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Keith A. Josephs, Bryan T. Klassen, Robert D. Fealey, Emily Owens, Anhar Hassan, Karl N. Krecke, J. E. Ahlskog, James H. Bower, and Joseph Y. Matsumoto
- Subjects
Male ,medicine.medical_specialty ,Pathology ,030218 nuclear medicine & medical imaging ,Progressive supranuclear palsy ,Midbrain ,03 medical and health sciences ,0302 clinical medicine ,Atrophy ,Mesencephalon ,Pons ,medicine ,Humans ,Aged ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Retrospective cohort study ,Magnetic resonance imaging ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,eye diseases ,nervous system diseases ,Clinical research ,Neurology ,Cohort ,Female ,Neurology (clinical) ,Radiology ,Supranuclear Palsy, Progressive ,Geriatrics and Gerontology ,business ,030217 neurology & neurosurgery ,Biomarkers - Abstract
The diagnosis of progressive supranuclear palsy is often challenging early in the course of the disease, when clinical signs of the condition may be less apparent and patients do not clearly meet diagnostic criteria. In this study, we examine a potential radiographic marker in progressive supranuclear palsy, and assess the timing of its presence in relation to diagnosis.A retrospective review of patients fulfilling clinical research criteria for multiple system atrophy, Parkinson's disease, and progressive supranuclear palsy (total n = 75) was performed. Midbrain and pontine diameters, and the midbrain to pons ratio were calculated by a neuroradiologist blinded to the clinical diagnosis. The timing of the presence of a midbrain to pons ratio of less than or equal to 0.52 was assessed in the progressive supranuclear palsy group in reference to the time of diagnosis.The midbrain to pons ratio was significantly reduced in the progressive supranuclear palsy cohort (p 0.0001), and a midbrain to pons ratio of less than or equal to 0.52 was 100% specific for progressive supranuclear palsy. This radiologic sign predated the clinical diagnosis of progressive supranuclear palsy by a mean of 15 months (range 1-47 months) in 14 of 17 (82%) of patients in whom it was found.The midbrain to pons ratio is an easily applied and highly specific tool in the diagnosis of progressive supranuclear palsy, and is frequently present before the diagnosis is made.
- Published
- 2016
42. Designing a Safer Radiology Department
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Rafael Miranda, Sherrie L. Prescott, Kenneth T. Aakre, Jodi M. Miller, C. Daniel Johnson, Karl N. Krecke, Howard H. Osborn, and Daniel F. Broderick
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Cross Infection ,medicine.medical_specialty ,Quality Assurance, Health Care ,Radiology Department, Hospital ,business.industry ,Contrast Media ,General Medicine ,Organizational Culture ,United States ,Harm ,Clinical Protocols ,SAFER ,Key (cryptography) ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Patient Safety ,Radiology ,business ,Risk management - Abstract
OBJECTIVE. Patients presume safety in radiologic services, but the potential to do harm exists in every area of imaging. Radiology department personnel need to understand basic regulatory requirements for safety and how to promote and improve safety in the future. CONCLUSION. This article reviews key safety metrics that we think are relevant to radiology and discusses how to define the measures and how we are attempting to translate the metrics into a culture of safety.
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- 2012
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43. NMR Structures of Thiostrepton Derivatives for Characterization of the Ribosomal Binding Site
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Sebastian Schoof, Hans-Dieter Arndt, Fabian Hiller, Harald Schwalbe, Karl N. Kirschner, Hendrik R. A. Jonker, Sascha Baumann, Kathrin W. Schulte, and Antje Wolf
- Subjects
Binding Sites ,Molecular Structure ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Thiostrepton ,Ribosome ,Catalysis ,Ribosomal binding site ,chemistry.chemical_compound ,Crystallography ,chemistry ,Humans ,Molecule ,Binding site ,Nuclear Magnetic Resonance, Biomolecular ,Ribosomes - Published
- 2011
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44. Hydrocephalus in neuromyelitis optica
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Clara D. Boyd, Corey A. McGraw, Sean J. Pittock, Claudia F. Lucchinetti, Brian G. Weinshenker, Stephen Krieger, Yong Guo, Vanda A. Lennon, Karl N. Krecke, Stacey L. Clardy, and Orna O'Toole
- Subjects
Adult ,Pathology ,medicine.medical_specialty ,Neuromyelitis optica ,Adult patients ,business.industry ,Neuromyelitis Optica ,Brain ,medicine.disease ,Hydrocephalus ,Aquaporin 4 ,Humans ,Medicine ,Female ,Neurology (clinical) ,Mri brain ,business ,Clinical/Scientific Notes - Abstract
A majority of patients with neuromyelitis optica (NMO) spectrum disorders (NMOSD) have MRI brain abnormalities, some of which are “NMO-typical” with localization in aquaporin 4 (AQP4)–rich circumventricular and periaqueductal regions.1 Although uncommon in adult patients, symptomatic brain involvement occurs in approximately 50% of NMO–immunoglobulin G (IgG) seropositive children. Here we report the clinical characteristics, type, and frequency of hydrocephalus in NMOSD.
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- 2014
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45. Sporadic leucodystrophy with neuroaxonal spheroids: persistence of DWI changes and neurocognitive profiles: a case study
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B. Mark Keegan, Joseph E. Parisi, Karl N. Krecke, Sean J. Pittock, Farrah J. Mateen, and Max R. Trenerry
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Pathology ,medicine.medical_specialty ,Neuroaxonal Dystrophies ,Neuropsychological Tests ,Severity of Illness Index ,Lesion ,Young Adult ,Biopsy ,medicine ,Humans ,Dementia ,Effective diffusion coefficient ,cardiovascular diseases ,Cognitive decline ,medicine.diagnostic_test ,Brain ,medicine.disease ,Axons ,Psychiatry and Mental health ,Diffusion Magnetic Resonance Imaging ,Hereditary diffuse leukoencephalopathy with spheroids ,Female ,Surgery ,Neurology (clinical) ,medicine.symptom ,Cognition Disorders ,Psychology ,Neurocognitive ,Diffusion MRI - Abstract
Leucodystrophy with neuroaxonal spheroids (LNS) is rare. There have been fewer than 10 sporadic cases reported, all occurring in the fourth to sixth decades of life. Previously unreported diffusion weighted imaging (DWI) changes on brain imaging in LNS are described as well as the first neurocognitive profile of this disorder in a 24-year-old woman. Neuropsychological testing demonstrated a global cognitive decline, with deficits most representative of a frontal-subcortical dementia. Bright DWI and corresponding dark apparent diffusion coefficient changes were initially mistaken for acute cerebral infarction but then persisted for 19 weeks. Biopsy of a bright DWI lesion showed no evidence of vascular disease and confirmed this rare diagnosis. Given the number of patients with the diagnosis of cerebrovascular disease, supported by DWI findings, we propose other milder cases of LNS may be overlooked.
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- 2010
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46. Antiestrogenic and anticancer activities of peptides derived from the active site of alpha-fetoprotein
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John Hughes, Herbert I. Jacobson, Karl N. Kirschner, Leroy C. Joseph, James A. Bennett, George C. Shields, Nicole Lostritto, and Thomas T. Andersen
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Transplantation, Heterologous ,Antineoplastic Agents ,Breast Neoplasms ,Peptide ,Pharmacology ,Biochemistry ,Mice ,chemistry.chemical_compound ,Estrogen Receptor Modulators ,Structural Biology ,In vivo ,Cell Line, Tumor ,Drug Discovery ,Animals ,Humans ,Amino Acid Sequence ,Molecular Biology ,chemistry.chemical_classification ,Binding Sites ,Chemistry ,Uterus ,Organic Chemistry ,Biological activity ,General Medicine ,Peptide Fragments ,In vitro ,AFPep ,Cancer cell ,Molecular Medicine ,Female ,alpha-Fetoproteins ,Growth inhibition ,Alpha-fetoprotein - Abstract
Cyclo[EKTOVNOGN] (AFPep), a cyclic 9-amino acid peptide derived from the active site of alpha-fetoprotein, has been shown to prevent carcinogen-induced mammary cancer in rats and inhibit the growth of ER(+) human breast cancer xenografts in mice. Recently, studies using replica exchange molecular dynamics predicted that the TOVN region of AFPep might form a dynamically stable putative Type I beta-turn, and thus be biologically active without additional amino acids. The studies presented in this paper were performed to determine whether TOVN and other small analogs of AFPep would inhibit estrogen-stimulated cancer growth and exhibit a broad effective-dose range. These peptides contained nine or fewer amino acids, and were designed to bracket or include the putative pharmacophoric region (TOVN) of AFPep. Biological activities of these peptides were evaluated using an immature mouse uterine growth inhibition assay, a T47D breast cancer cell proliferation assay, and an MCF-7 breast cancer xenograft assay. TOVN had very weak antiestrogenic activity in comparison to AFPep's activity, whereas TOVNO had antiestrogenic and anticancer activities similar to AFPep. OVNO, which does not form a putative Type I beta-turn, had virtually no antiestrogenic and anticancer activities. A putative proteolytic cleavage product of AFPep, TOVNOGNEK, significantly inhibited E(2)-stimulated growth in vivo and in vitro over a wider dose range than AFPep or TOVNO. We conclude that TOVNO has anticancer potential, that TOVNOGNEK is as effective as AFPep in suppressing growth of human breast cancer cells, and that it does so over a broader effective-dose range.
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- 2009
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47. Key Concepts of Patient Safety in Radiology
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David B. Larson, Karl N. Krecke, Lane F. Donnelly, and Jonathan B. Kruskal
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medicine.medical_specialty ,Safety Management ,Quality management ,Systems Analysis ,Quality Assurance, Health Care ,Attitude of Health Personnel ,media_common.quotation_subject ,Human error ,Organizational culture ,Patient safety ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Quality (business) ,media_common ,Medical Errors ,Radiology Department, Hospital ,business.industry ,Quality Improvement ,Harm ,Quality management system ,Organizational safety ,Radiology ,Clinical Competence ,Patient Safety ,business - Abstract
Harm from medical error is a difficult challenge in health care, including radiology. Modern approaches to patient safety have shifted from a focus on individual performance and reaction to errors to development of robust systems and processes that create safety in organizations. Organizations that operate safely in high-risk environments have been termed high-reliability organizations. Such organizations tend to see themselves as being constantly bombarded by errors. Thus, the goal is not to eliminate human error but to develop strategies to prevent, identify, and mitigate errors and their effects before they result in harm. High-level reliability strategies focus on systems and organizational culture; intermediate-level reliability strategies focus on establishment of effective processes; low-level reliability strategies focus on individual performance. Although several classification schemes for human error exist, modern safety researchers caution against overreliance on error investigations to improve safety. Blaming individuals involved in adverse events when they had no intent to cause harm has been shown to undermine organizational safety. Safety researchers have coined the term just culture for the successful balance of individual accountability with accommodation for human fallibility and system deficiencies. Safety is inextricably intertwined with an organization's quality efforts. A quality management system that focuses on standardization, making errors visible, building in quality, and constantly stopping to fix problems results in a safer environment and engages personnel in a way that contributes to a culture of safety.
- Published
- 2015
48. Short myelitis lesions in aquaporin-4-IgG-positive neuromyelitis optica spectrum
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Flanagan, Eoin P., Weinshenker, Brian G., Krecke, Karl N., Lennon, Vanda A., Lucchinetti, Claudia F., McKeon, Andrew, Wingerchuk, Dean M., Shuster, Elizabeth A., Jiao, Yujuan, Horta, Erika S., and Pittock, Sean J.
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Adult ,Aquaporin 4 ,Male ,Neuromyelitis Optica ,Middle Aged ,Myelitis ,Magnetic Resonance Imaging ,Article ,Statistics, Nonparametric ,Spinal Cord ,Immunoglobulin G ,Humans ,Female ,Longitudinal Studies ,Aged - Abstract
Short transverse myelitis (STM;3 vertebral segments) is considered noncharacteristic of neuromyelitis optica (NMO) spectrum disorders (NMOSDs). Nonappreciation of the potential for STM to occur in NMOSD may lead to increased disability from delay in diagnosis and appropriate treatment.To determine the frequency of short lesions at the initial myelitis manifestation of NMOSD and to compare the demographic, clinical, and radiological characteristics of aquaporin-4-IgG (AQP4-IgG) seropositive and seronegative STM.We reviewed the records and images of patients at the Mayo Clinic who were identified as AQP4-IgG positive from 1996 to 2014. Inclusion criteria were first STM episode, magnetic resonance imaging performed 90 days or less from symptom onset, spinal cord T2-hyperintense lesion less than 3 vertebral segments, AQP4-IgG seropositivity, and a final diagnosis of NMO or NMOSD. Patients with an initial longitudinally extensive transverse myelitis were excluded (n = 151). Patients with STM who were seronegative for AQP4-IgG among an Olmsted County population-based cohort of inflammatory demyelinating disorders of the central nervous system were used as a control group.Delay to diagnosis in months, clinical and radiological characteristics, and disability measured by ambulatory status.Twenty-five patients who were AQP4-IgG seropositive with an initial STM represented 14% of initial myelitis episodes among patients with NMOSD. The STM episode was defined as the first manifestation of NMOSD in 10 patients (40%) preceded by optic neuritis in 13 patients (52%) and preceded by a nausea and vomiting episode in 2 patients (8%). In comparison with the excluded patients with NMOSD who had an initial longitudinally extensive transverse myelitis, delay to diagnosis/treatment was greater when initial lesions were short (P = .02). In AQP4-IgG-positive STM cases, subsequent myelitis episodes were longitudinally extensive in 92%. Attributes more common in patients with AQP4-IgG-positive STM than in 27 population-based patients with AQP4-IgG-negative STM included the following: nonwhite race/ethnicity; tonic spasms; coexisting autoimmunity; magnetic resonance imaging (central cord lesions, T1 hypointensity, and a brain inconsistent with multiple sclerosis); and cerebrospinal fluid (oligoclonal bands lacking).Short transverse myelitis is not uncommon in NMOSD and, when it is present, delays diagnosis and treatment. Clinical and radiological characteristics identified in this study may help select patients with STM who are at the highest risk for an NMOSD. Short transverse myelitis does not exclude consideration of AQP4-IgG testing or NMOSD diagnosis.
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- 2015
49. Patient Outcomes After Vestibular Schwannoma Management: a Prospective Comparison of Microsurgical Resection and Stereotactic Radiosurgery
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Colin L. W. Driscoll, Bruce E. Pollock, Jayawant N. Mandrekar, Karl N. Krecke, Christopher D. Bauch, Robert L. Foote, Deborah A. Gorman, Craig H. Johnson, and Michael J. Link
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Male ,Microsurgery ,medicine.medical_specialty ,Hearing loss ,Health Status ,Movement ,medicine.medical_treatment ,Facial Muscles ,Acoustic neuroma ,Radiosurgery ,Dizziness ,Cohort Studies ,Hearing ,Quality of life ,Surveys and Questionnaires ,Humans ,Medicine ,Single-Blind Method ,Postoperative Period ,Prospective Studies ,Prospective cohort study ,Pain, Postoperative ,business.industry ,Neuroma, Acoustic ,Middle Aged ,medicine.disease ,Neuroma ,Surgery ,Treatment Outcome ,Quality of Life ,Female ,Neurology (clinical) ,medicine.symptom ,business ,Cohort study - Abstract
OBJECTIVE: The best management for patients with small- to medium-sized vestibular schwannomas (VS) is controversial. METHODS: A prospective cohort study of 82 patients with unilateral, unoperated VS less than 3 cm undergoing surgical resection (n = 36) or radiosurgery (n = 46). Patients undergoing resection were younger (48.2 yr versus 53.9 yr, P = 0.03). The groups were similar with regard to hearing loss, associated symptoms, and tumor size. The mean follow-up period was 42 months (range, 12-62 mo). RESULTS: Normal facial movement and preservation of serviceable hearing was more frequent in the radiosurgical group at 3 months (P < 0.001), 1 year (P < 0.001), and at the last follow-up examination (P < 0.01) compared with the surgical resection group. Patients undergoing surgical resection had a significant decline in the following subscales of the Health Status Questionnaire 3 months after surgery: physical functioning (P = 0.006), role-physical (P < 0.001), energy/fatigue (P = 0.02), and overall physical component (P = 0.004). Patients in the surgical resection group continued to have a significant decline in the physical functioning (P = 0.04) and bodily pain (P = 0.04) subscales at 1 year and in bodily pain (P = 0.02) at the last follow-up examination. The radiosurgical group had no decline on any component of the Health Status Questionnaire after the procedure. The radiosurgical group had lower mean Dizziness Handicap Inventory scores (16.5 versus 8.4, P = 0.02) at the last follow-up examination. There was no difference in tumor control (100 versus 96%, P = 0.50). CONCLUSION: Early outcomes were better for VS patients undergoing stereotactic radiosurgery compared with surgical resection (Level 2 evidence). Unless long-term follow-up evaluation shows frequent tumor progression at currently used radiation doses, radiosurgery should be considered the best management strategy for the majority of VS patients.
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- 2006
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50. Central canal enhancement and the trident sign in spinal cord sarcoidosis
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Andrew McKeon, Allen J. Aksamit, Brittani L. Conway, Karl N. Krecke, Nicholas L. Zalewski, Eoin P. Flanagan, and Brian G. Weinshenker
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medicine.medical_specialty ,Weakness ,Sarcoidosis ,Urinary system ,Myelitis ,030204 cardiovascular system & hematology ,Spinal Cord Diseases ,Diagnosis, Differential ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Sensory level ,Lung ,Proprioception ,business.industry ,Spinal cord ,medicine.disease ,Magnetic Resonance Imaging ,Surgery ,medicine.anatomical_structure ,Spinal Cord ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
We report an enhancement pattern in 9 patients with spinal cord sarcoidosis (SCS) with subacute onset (
- Published
- 2016
- Full Text
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