80 results on '"Bag AK"'
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2. Ideas and Researches on Physical Concepts in India
- Author
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Bag, AK, primary
- Published
- 2015
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3. Book Review: A Selected Works of Gurugovinda Chakravarti on Ancient and Medieval Indian Mathematics
- Author
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Bag, AK, primary
- Published
- 2015
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4. Are There Differences between Macrocyclic Gadolinium Contrast Agents for Brain Tumor Imaging? Results of a Multicenter Intraindividual Crossover Comparison of Gadobutrol with Gadoteridol (the TRUTH Study)
- Author
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Maravilla, Kr, Smith, Mp, Vymazal, J, Goyal, M, Herman, M, Baima, Jj, Babbel, R, Vaneckova, M, Žižka, J, Colosimo, Cesare, Urbańczyk Zawadzka, M, Mechl, M, Bag, Ak, Bastianello, S, Bueltmann, E, Hirai, T, Frattini, T, Kirchin, Ma, Pirovano, G., Colosimo, Cesare (ORCID:0000-0003-3800-3648), Maravilla, Kr, Smith, Mp, Vymazal, J, Goyal, M, Herman, M, Baima, Jj, Babbel, R, Vaneckova, M, Žižka, J, Colosimo, Cesare, Urbańczyk Zawadzka, M, Mechl, M, Bag, Ak, Bastianello, S, Bueltmann, E, Hirai, T, Frattini, T, Kirchin, Ma, Pirovano, G., and Colosimo, Cesare (ORCID:0000-0003-3800-3648)
- Abstract
Gadobutrol (Gadavist) and gadoteridol (ProHance) have similar macrocyclic molecular structures, but gadobutrol is formulated at a 2-fold higher (1 mol/L versus 0.5 mol/L) concentration. We sought to determine whether this difference impacts morphologic contrast-enhanced MR imaging.
- Published
- 2014
5. Strategic Involvement of Facial Colliculus in SLE
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Bag, AK, primary and Chapman, PR, additional
- Published
- 2010
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6. Central variant of posterior reversible encephalopathy syndrome in systemic lupus erythematosus: new associations?
- Author
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Bag, AK, primary, Curé, JK, additional, Sullivan, JC, additional, and Roberson, GH, additional
- Published
- 2009
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7. Prolapsing anterior urethral polyp
- Author
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Pal, DilipKumar, primary and Bag, AK, additional
- Published
- 2006
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8. Recurrent rhinosporidiosis of male urethra.
- Author
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Pal DK, Bhattacharyya N, Bag AK, and Sinha L
- Abstract
Rhinosporidiosis is a chronic granulomatous disease caused by a fungus, Rhinisporidium seeberi. Though the favored site is the nasal mucosa, urethral involvement does occur in this disease, only a few cases are reported in the literature and they are mostly from India. Here we report a case of recurrent urethral rhinosporidiosis, presenting as a protruding mass from the urethral orifice during voiding. [ABSTRACT FROM AUTHOR]
- Published
- 2006
9. Concurrent ependymal and ganglionic differentiation in a subset of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement.
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Lee JC, Koo SC, Furtado LV, Breuer A, Eldomery MK, Bag AK, Stow P, Rose G, Larkin T, Sances R, Kleinschmidt-DeMasters BK, Bodmer JL, Willard N, Gokden M, Dahiya S, Roberts K, Bertrand KC, Moreira DC, Robinson GW, Mo JQ, Ellison DW, and Orr BA
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- Adolescent, Adult, Child, Child, Preschool, Female, Humans, Male, Young Adult, Cell Differentiation, Chromosomal Proteins, Non-Histone genetics, DNA-Binding Proteins genetics, Ependyma pathology, Gene Rearrangement genetics, Neoplasms, Neuroepithelial genetics, Neoplasms, Neuroepithelial pathology, Oncogene Proteins, Fusion genetics, RNA-Binding Protein EWS genetics, Supratentorial Neoplasms genetics, Supratentorial Neoplasms pathology, Transcription Factors genetics
- Abstract
Neuroepithelial tumors with fusion of PLAGL1 or amplification of PLAGL1/PLAGL2 have recently been described often with ependymoma-like or embryonal histology respectively. To further evaluate emerging entities with PLAG-family genetic alterations, the histologic, molecular, clinical, and imaging features are described for 8 clinical cases encountered at St. Jude (EWSR1-PLAGL1 fusion n = 6; PLAGL1 amplification n = 1; PLAGL2 amplification n = 1). A histologic feature observed on initial resection in a subset (4/6) of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement was the presence of concurrent ependymal and ganglionic differentiation. This ranged from prominent clusters of ganglion cells within ependymoma/subependymoma-like areas, to interspersed ganglion cells of low to moderate frequency among otherwise ependymal-like histology, or focal areas with a ganglion cell component. When present, the combination of ependymal-like and ganglionic features within a supratentorial neuroepithelial tumor may raise consideration for an EWSR1-PLAGL1 fusion, and prompt initiation of appropriate molecular testing such as RNA sequencing and methylation profiling. One of the EWSR1-PLAGL1 fusion cases showed subclonal INI1 loss in a region containing small clusters of rhabdoid/embryonal cells, and developed a prominent ganglion cell component on recurrence. As such, EWSR1-PLAGL1 neuroepithelial tumors are a tumor type in which acquired inactivation of SMARCB1 and development of AT/RT features may occur and lead to clinical progression. In contrast, the PLAGL2 and PLAGL1 amplified cases showed either embryonal histology or contained an embryonal component with a significant degree of desmin staining, which could also serve to raise consideration for a PLAG entity when present. Continued compilation of associated clinical data and histopathologic findings will be critical for understanding emerging entities with PLAG-family genetic alterations., (© 2024. The Author(s).)
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- 2024
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10. Reliability of In Vivo Creatine-Weighted Chemical Exchange Saturation Transfer (CrCEST) MRI in Calf Skeletal Muscle of Healthy Volunteers at 3 T.
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Chakraborty K, Burman R, Nisar S, Miller S, Loschinskey Z, Wu S, Li Y, Bag AK, Khan A, Goodenough C, Wilson N, Haris M, McCormack SE, Reddy R, Ness K, Finkel R, and Bagga P
- Abstract
Background: Skeletal muscle mitochondrial oxidative phosphorylation (mtOXPHOS) is important for ATP generation and its dysfunction leads to exercise intolerance. Phosphorus magnetic resonance spectroscopy (
31 P-MRS) is a useful, noninvasive technique for mtOXPHOS assessment but has limitations. Creatine-weighted chemical exchange saturation transfer (CrCEST) MRI is a potential alternative to assess muscle bioenergetics., Purpose: To evaluate the interscan repeatability, intra- and interobserver reproducibility of CrCEST during mild plantar flexion exercise., Study Type: Retrospective., Subjects: Twenty healthy volunteers (age 37.6 ± 12.4 years, 11 females)., Field Strength/sequence: 3 T/CEST imaging using gradient echo readout., Assessment: τCrCEST (postexercise Cr recovery time) was assessed in two scans for each participant, following mild plantar flexion exercises targeting the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (Sol) muscles. Three observers measured τCrCEST for interobserver reproducibility. Three readings by one observer were used to measure intraobserver reproducibility. Two scans were used for within-participant interscan repeatability., Statistical Tests: Paired t tests, intraclass correlation coefficient (ICC), and Pearson correlation were conducted. Bland-Altman plots were used to analyze the interobserver variability. A P-value of 0.05 was considered statistically significant., Results: There was excellent intra- (ICC ∈ 0.94 - 0.98 $$ \in \left[0.94-0.98\right] $$ ) and interobserver (ICC ∈ 0.9 - 0.98 $$ \in \left[0.9-0.98\right] $$ ) reproducibility, with moderate interscan repeatability for τCrCEST in LG and MG (ICC ∈ 0.54 - 0.74 $$ \in \left[0.54-0.74\right] $$ ) and poor-to-moderate interscan repeatability in Sol (ICC ∈ 0.24 - 0.53 $$ \in \left[0.24-0.53\right] $$ ). Excellent interobserver reproducibility was confirmed by Bland-Altman plots (fixed bias P-value ∈ 0.08 - 0.87 $$ \in \left[0.08-0.87\right] $$ )., Data Conclusion: CrCEST MRI shows promise in assessing muscle bioenergetics by evaluating τCrCEST during mild plantar flexion exercise with reasonable reliability, particularly in LG and MG., Level of Evidence: 4 TECHNICAL EFFICACY: Stage 1., (© 2024 International Society for Magnetic Resonance in Medicine.)- Published
- 2024
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11. Simultaneous Presentation of B-Acute Lymphoblastic Leukemia and Streptococcus agalactiae Meningitis in a 3-Year-old Girl.
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Purvis K, Hiskey L, Khanlari M, Mead PE, Holland AC, Bag AK, Adderson E, and Inaba H
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- Humans, Female, Child, Preschool, Meningitis, Bacterial drug therapy, Meningitis, Bacterial microbiology, Meningitis, Bacterial diagnosis, Vincristine administration & dosage, Vincristine therapeutic use, Precursor Cell Lymphoblastic Leukemia-Lymphoma drug therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma complications, Bacteremia drug therapy, Bacteremia microbiology, Streptococcus agalactiae, Streptococcal Infections drug therapy, Streptococcal Infections microbiology, Precursor B-Cell Lymphoblastic Leukemia-Lymphoma drug therapy, Precursor B-Cell Lymphoblastic Leukemia-Lymphoma complications, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Dexamethasone therapeutic use, Dexamethasone administration & dosage
- Abstract
Infection is a major cause of treatment-related morbidity and mortality in pediatric acute lymphoblastic leukemia (ALL). Most children with ALL who develop life-threatening bacterial infections do so during induction therapy. We describe a rare case of ALL presenting simultaneously with Streptococcus agalactiae group B Streptococcus bacteremia and meningitis in a 3-year-old girl. She received appropriate antimicrobial therapy and a 2-drug early induction regimen consisting of vincristine and dexamethasone, leading to slow neurologic recovery and a favorable initial response to anti-neoplastic therapy as evidenced by minimal residual disease of 1.12% on day 15 of induction., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2024
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12. Cerebellar Mutism Syndrome and Dentato-Thalamo-Cortical Tract Disruption in Diffusion Tractography Following Surgery for Medulloblastoma.
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Ji Q, McAfee SS, Scoggins M, Holtrop J, Glass JO, Yuan X, Liang J, Li Y, Chiang J, Orr BA, Edwards A, Storment D, Brinkman T, Robinson GW, Gajjar A, Reddick WE, Patay Z, Khan RB, and Bag AK
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- Humans, Male, Female, Retrospective Studies, Child, Case-Control Studies, Adolescent, Neural Pathways diagnostic imaging, Thalamus diagnostic imaging, Medulloblastoma surgery, Medulloblastoma diagnostic imaging, Mutism etiology, Mutism diagnostic imaging, Diffusion Tensor Imaging methods, Cerebellar Neoplasms diagnostic imaging, Cerebellar Neoplasms surgery, Postoperative Complications diagnostic imaging
- Abstract
Background Cerebellar mutism syndrome (CMS), a complication following medulloblastoma surgery, has been linked to dentato-thalamo-cortical tract (DTCT) injury; the association of the degree of DTCT injury with severity of CMS-related symptoms has not been investigated. Purpose To investigate the association between severity of CMS-related symptoms and degree and patterns of DTCT injury with use of diffusion tensor imaging (DTI), and if laterality of injury influences neurologic symptoms. Materials and Methods This retrospective case-control study used prospectively collected clinical and DTI data on patients with medulloblastoma enrolled in a clinical trial (between July 2016 and February 2020) and healthy controls (between April and November 2017), matched with the age range of the participants with medulloblastoma. CMS was divided into types 1 (CMS1) and 2 (CMS2). Multivariable logistic regression was used to investigate the relationship between CMS likelihood and DTCT injury. Results Overall, 82 participants with medulloblastoma (mean age, 11.0 years ± 5.2 [SD]; 53 male) and 35 healthy controls (mean age, 18.0 years ± 3.06; 18 female) were included. In participants with medulloblastoma, DTCT was absent bilaterally (AB), absent on the right side (AR), absent on the left side (AL), or present bilaterally (PB), while it was PB in all healthy controls. Odds of having CMS were associated with higher degree of DTCT damage (AB, odds ratio = 272.7 [95% CI: 269.68, 275.75; P < .001]; AR, odds ratio = 14.40 [95% CI: 2.84, 101.48; P < .001]; and AL, odds ratio = 8.55 [95% CI: 1.15, 74.14; P < .001). Left (coefficient = -0.07, χ
2 = 12.4, P < .001) and right (coefficient = -0.15, χ2 = 33.82, P < .001) DTCT volumes were negatively associated with the odds of CMS. More participants with medulloblastoma with AB showed CMS1; unilateral DTCT absence prevailed in CMS2. Lower DTCT volumes correlated with more severe ataxia. Unilateral DTCT injury caused ipsilateral dysmetria; AB caused symmetric dysmetria. PB indicated better neurologic outcome. Conclusion The severity of CMS-associated mutism, ataxia, and dysmetria was associated with DTCT damage severity. DTCT damage patterns differed between CMS1 and CMS2. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Dorigatti Soldatelli and Ertl-Wagner in this issue.- Published
- 2024
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13. [11C]-methionine positron emission tomography in the evaluation of pediatric low-grade gliomas.
- Author
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Kim EY, Vavere AL, Snyder SE, Chiang J, Li Y, Patni T, Qaddoumi I, Merchant TE, Robinson GW, Holtrop JL, Shulkin BL, and Bag AK
- Abstract
Background: [
11 C]-Methionine positron emission tomography (PET; [11 C]-MET-PET) is principally used for the evaluation of brain tumors in adults. Although amino acid PET tracers are more commonly used in the evaluation of pediatric brain tumors, data on [11 C]-MET-PET imaging of pediatric low-grade gliomas (pLGG) is scarce. This study aimed to investigate the roles of [11 C]-MET-PET in the evaluation of pLGGs., Methods: Eighteen patients with newly diagnosed pLGG and 26 previously treated pLGG patients underwent [11 C]-MET-PET met the inclusion and exclusion criteria. Tumor-to-brain uptake ratio (TBR) and metabolic tumor volumes were assessed for diagnostic performances (newly diagnosed, 15; previously treated 26), change with therapy (newly diagnosed, 9; previously treated 7), and variability among different histology ( n = 12) and molecular markers ( n = 7) of pLGGs., Results: The sensitivity of [11 C]-MET-PET for diagnosing pLGG, newly diagnosed, and previously treated combined was 93% for both TBRmax and TBRpeak , 76% for TBRmean , and 95% for qualitative evaluation. TBRmax showed a statistically significant reduction after treatment, while other PET parameters showed a tendency to decrease. Median TBRmax , TBRpeak , and TBRmean values were slightly higher in the BRAFV600E mutated tumors compared to the BRAF fused tumors. Median TBRmax , and TBRpeak in diffuse astrocytomas were higher compared to pilocytic astrocytomas, but median TBRmean , was slightly higher in pilocytic astrocytomas. However, formal statistical analysis was not done due to the small sample size., Conclusions: Our study shows that [11 C]-MET-PET reliably characterizes new and previously treated pLGGs. Our study also shows that quantitative parameters tend to decrease with treatment, and differences may exist between various pLGG types., Competing Interests: Financial disclosure: No potential conflicts of interest relevant to this article exist. Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health., (© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)- Published
- 2024
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14. Atypical teratoid/rhabdoid tumour-TYR subtype arising in the setting of germline ring chromosome 22: An uncommon form of tumour predisposition.
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Lee JC, Tran QT, McGee RB, Perrino MR, Upadhyaya SA, Hanzlik EM, Pytel N, Carroll AJ, Orisme W, Eldomery M, Wang L, Blackburn PR, Furtado LV, Viaene AN, Luo M, Kalish JM, Pinto SN, Bag AK, and Orr BA
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- Humans, SMARCB1 Protein genetics, Germ Cells pathology, Rhabdoid Tumor genetics, Rhabdoid Tumor pathology, Ring Chromosomes, Central Nervous System Neoplasms, Teratoma genetics
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- 2024
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15. Generic model to unravel the deeper insights of viral infections: an empirical application of evolutionary graph coloring in computational network biology.
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Kole A, Bag AK, Pal AJ, and De D
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- Humans, SARS-CoV-2, Protein Interaction Maps genetics, Biology, Computational Biology, Pandemics, COVID-19
- Abstract
Purpose: Graph coloring approach has emerged as a valuable problem-solving tool for both theoretical and practical aspects across various scientific disciplines, including biology. In this study, we demonstrate the graph coloring's effectiveness in computational network biology, more precisely in analyzing protein-protein interaction (PPI) networks to gain insights about the viral infections and its consequences on human health. Accordingly, we propose a generic model that can highlight important hub proteins of virus-associated disease manifestations, changes in disease-associated biological pathways, potential drug targets and respective drugs. We test our model on SARS-CoV-2 infection, a highly transmissible virus responsible for the COVID-19 pandemic. The pandemic took significant human lives, causing severe respiratory illnesses and exhibiting various symptoms ranging from fever and cough to gastrointestinal, cardiac, renal, neurological, and other manifestations., Methods: To investigate the underlying mechanisms of SARS-CoV-2 infection-induced dysregulation of human pathobiology, we construct a two-level PPI network and employed a differential evolution-based graph coloring (DEGCP) algorithm to identify critical hub proteins that might serve as potential targets for resolving the associated issues. Initially, we concentrate on the direct human interactors of SARS-CoV-2 proteins to construct the first-level PPI network and subsequently applied the DEGCP algorithm to identify essential hub proteins within this network. We then build a second-level PPI network by incorporating the next-level human interactors of the first-level hub proteins and use the DEGCP algorithm to predict the second level of hub proteins., Results: We first identify the potential crucial hub proteins associated with SARS-CoV-2 infection at different levels. Through comprehensive analysis, we then investigate the cellular localization, interactions with other viral families, involvement in biological pathways and processes, functional attributes, gene regulation capabilities as transcription factors, and their associations with disease-associated symptoms of these identified hub proteins. Our findings highlight the significance of these hub proteins and their intricate connections with disease pathophysiology. Furthermore, we predict potential drug targets among the hub proteins and identify specific drugs that hold promise in preventing or treating SARS-CoV-2 infection and its consequences., Conclusion: Our generic model demonstrates the effectiveness of DEGCP algorithm in analyzing biological PPI networks, provides valuable insights into disease biology, and offers a basis for developing novel therapeutic strategies for other viral infections that may cause future pandemic., (© 2024. The Author(s).)
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- 2024
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16. Cerebellar mutism is linked to midbrain volatility and desynchronization from speech cortices.
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McAfee SS, Robinson G, Gajjar A, Zhang S, Bag AK, Raches D, Conklin HM, Khan RB, and Scoggins MA
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- Humans, Speech, Cerebellum pathology, Mesencephalon, Postoperative Complications, Medulloblastoma surgery, Medulloblastoma pathology, Mutism etiology, Mutism pathology, Cerebellar Neoplasms pathology, Cerebellar Diseases complications
- Abstract
Cerebellar mutism syndrome is a disorder of speech, movement and affect that can occur after tumour removal from the posterior fossa. Projections from the fastigial nuclei to the periaqueductal grey area were recently implicated in its pathogenesis, but the functional consequences of damaging these projections remain poorly understood. Here, we examine functional MRI data from patients treated for medulloblastoma to identify functional changes in key brain areas that comprise the motor system for speech, which occur along the timeline of acute speech impairment in cerebellar mutism syndrome. One hundred and twenty-four participants, all with medulloblastoma, contributed to the study: 45 with cerebellar mutism syndrome, 11 patients with severe postoperative deficits other than mutism, and 68 without either (asymptomatic). We first performed a data-driven parcellation to spatially define functional nodes relevant to the cohort that align with brain regions critical for the motor control of speech. We then estimated functional connectivity between these nodes during the initial postoperative imaging sessions to identify functional deficits associated with the acute phase of the disorder. We further analysed how functional connectivity changed over time within a subset of participants that had suitable imaging acquired over the course of recovery. Signal dispersion was also measured in the periaqueductal grey area and red nuclei to estimate activity in midbrain regions considered key targets of the cerebellum with suspected involvement in cerebellar mutism pathogenesis. We found evidence of periaqueductal grey dysfunction in the acute phase of the disorder, with abnormal volatility and desynchronization with neocortical language nodes. Functional connectivity with periaqueductal grey was restored in imaging sessions that occurred after speech recovery and was further shown to be increased with left dorsolateral prefrontal cortex. The amygdalae were also broadly hyperconnected with neocortical nodes in the acute phase. Stable connectivity differences between groups were broadly present throughout the cerebrum, and one of the most substantial differences-between Broca's area and the supplementary motor area-was found to be inversely related to cerebellar outflow pathway damage in the mutism group. These results reveal systemic changes in the speech motor system of patients with mutism, centred on limbic areas tasked with the control of phonation. These findings provide further support for the hypothesis that periaqueductal grey dysfunction (following cerebellar surgical injury) contributes to the transient postoperative non-verbal episode commonly observed in cerebellar mutism syndrome but highlights a potential role of intact cerebellocortical projections in chronic features of the disorder., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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17. CD19 CAR T-cell therapy demonstrates activity against extramedullary disease in pediatric patients with B-ALL.
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Epperly R, Shulkin BL, Bag AK, Cheng C, Inaba H, Lucas JT, Naik S, Triplett BM, Gottschalk S, and Talleur AC
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- Humans, Child, T-Lymphocytes, Receptors, Antigen, T-Cell, Antigens, CD19, Immunotherapy, Adoptive adverse effects, Burkitt Lymphoma
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- 2023
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18. Imaging of pediatric spine and spinal cord tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee/ASPNR White Paper.
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Rogers SN, Udayasankar U, Pruthi S, Lai HA, Kadom N, Guerin J, Malinzak M, Shulkin BL, Poussaint TY, Patay Z, and Bag AK
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- Child, Humans, Spine, Spinal Cord, Magnetic Resonance Imaging, Surface Plasmon Resonance, Spinal Cord Neoplasms diagnostic imaging
- Abstract
Childhood spinal tumors are rare. Tumors can involve the spinal cord, the meninges, bony spine, and the paraspinal tissue. Optimized imaging should be utilized to evaluate tumors arising from specific spinal compartments. This paper provides consensus-based recommendations for optimized imaging of tumors arising from specific spinal compartments at diagnosis, follow-up during and after therapy, and response assessment., (© 2022 Wiley Periodicals LLC.)
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- 2023
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19. Predicting methylation class from diffusely infiltrating adult gliomas using multimodality MRI data.
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Alom Z, Tran QT, Bag AK, Lucas JT, and Orr BA
- Abstract
Background: Radiogenomic studies of adult-type diffuse gliomas have used magnetic resonance imaging (MRI) data to infer tumor attributes, including abnormalities such as IDH-mutation status and 1p19q deletion. This approach is effective but does not generalize to tumor types that lack highly recurrent alterations. Tumors have intrinsic DNA methylation patterns and can be grouped into stable methylation classes even when lacking recurrent mutations or copy number changes. The purpose of this study was to prove the principle that a tumor's DNA-methylation class could be used as a predictive feature for radiogenomic modeling., Methods: Using a custom DNA methylation-based classification model, molecular classes were assigned to diffuse gliomas in The Cancer Genome Atlas (TCGA) dataset. We then constructed and validated machine learning models to predict a tumor's methylation family or subclass from matched multisequence MRI data using either extracted radiomic features or directly from MRI images., Results: For models using extracted radiomic features, we demonstrated top accuracies above 90% for predicting IDH-glioma and GBM-IDHwt methylation families, IDH-mutant tumor methylation subclasses, or GBM-IDHwt molecular subclasses. Classification models utilizing MRI images directly demonstrated average accuracies of 80.6% for predicting methylation families, compared to 87.2% and 89.0% for differentiating IDH-mutated astrocytomas from oligodendrogliomas and glioblastoma molecular subclasses, respectively., Conclusions: These findings demonstrate that MRI-based machine learning models can effectively predict the methylation class of brain tumors. Given appropriate datasets, this approach could generalize to most brain tumor types, expanding the number and types of tumors that could be used to develop radiomic or radiogenomic models., (© The Author(s) 2023. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)
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- 2023
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20. The clinical and molecular characteristics of progressive hypothalamic/optic pathway pilocytic astrocytoma.
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Li X, Moreira DC, Bag AK, Qaddoumi I, Acharya S, and Chiang J
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- Humans, Male, Child, Preschool, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism, Tumor Suppressor Protein p53, TOR Serine-Threonine Kinases metabolism, Proto-Oncogene Proteins B-raf genetics, Astrocytoma genetics, Brain Neoplasms genetics
- Abstract
Background: Unresectable hypothalamic/optic pathway pilocytic astrocytoma (PA) often progresses despite multiple therapies. Identifying clinical and molecular characteristics of progressive tumors may aid in prognostication and treatment., Methods: We collected 72 unresectable, non-neurofibromatosis type 1-associated hypothalamic/optic pathway PA to identify clinical and biologic factors associated with tumor progression. Tumors that progressed after therapy, metastasized, or resulted in death were categorized into Cohort B; those that did not meet these criteria were categorized into Cohort A. DNA methylation and transcriptome analyses were performed on treatment-naïve tumors, and the findings were validated by immunohistochemistry (IHC)., Results: The median follow-up of the entire cohort was 12.3 years. Cohort B was associated with male sex (M:F = 2.6:1), younger age at diagnosis (median 3.2 years vs 6.7 years, P = .005), and high incidence of KIAA1549-BRAF fusion (81.5% vs 38.5%, P = .0032). Cohort B demonstrated decreased CpG methylation and increased RNA expression in mitochondrial genes and genes downstream of E2F and NKX2.3. Transcriptome analysis identified transcription factor TBX3 and protein kinase PIM1 as common downstream targets of E2F and NKX2.3. IHC confirmed increased expression of TBX3 and PIM1 in Cohort B tumors. Gene enrichment analysis identified enrichment of MYC targets and MAPK, PI3K/AKT/mTOR, and p53 pathways, as well as pathways related to mitochondrial function., Conclusions: We identified risk factors associated with progressive PA. Our results support the model in which the p53-PIM1-MYC axis and TBX3 act alongside MAPK and PI3K/AKT/mTOR pathways to promote tumor progression, highlighting potential new targets for combination therapy and refining disease prognostication., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)
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- 2023
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21. Standard clinical approaches and emerging modalities for glioblastoma imaging.
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Bernstock JD, Gary SE, Klinger N, Valdes PA, Ibn Essayed W, Olsen HE, Chagoya G, Elsayed G, Yamashita D, Schuss P, Gessler FA, Paolo Peruzzi P, Bag AK, and Friedman GK
- Abstract
Glioblastoma (GBM) is the most common primary adult intracranial malignancy and carries a dismal prognosis despite an aggressive multimodal treatment regimen that consists of surgical resection, radiation, and adjuvant chemotherapy. Radiographic evaluation, largely informed by magnetic resonance imaging (MRI), is a critical component of initial diagnosis, surgical planning, and post-treatment monitoring. However, conventional MRI does not provide information regarding tumor microvasculature, necrosis, or neoangiogenesis. In addition, traditional MRI imaging can be further confounded by treatment-related effects such as pseudoprogression, radiation necrosis, and/or pseudoresponse(s) that preclude clinicians from making fully informed decisions when structuring a therapeutic approach. A myriad of novel imaging modalities have been developed to address these deficits. Herein, we provide a clinically oriented review of standard techniques for imaging GBM and highlight emerging technologies utilized in disease characterization and therapeutic development., (© The Author(s) 2022. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)
- Published
- 2022
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22. 11 C-Methionine PET for Identification of Pediatric High-Grade Glioma Recurrence.
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Bag AK, Wing MN, Sabin ND, Hwang SN, Armstrong GT, Han Y, Li Y, Snyder SE, Robinson GW, Qaddoumi I, Broniscer A, Lucas JT, and Shulkin BL
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- Child, Humans, Magnetic Resonance Imaging methods, Methionine, Neoplasm Recurrence, Local diagnostic imaging, Neoplasm Recurrence, Local pathology, Positron-Emission Tomography methods, Brain Neoplasms pathology, Glioma pathology
- Abstract
Differentiating tumor recurrence or progression from pseudoprogression during surveillance of pediatric high-grade gliomas (PHGGs) using MRI, the primary imaging modality for evaluation of brain tumors, can be challenging. The aim of this study was to evaluate whether
11 C-methionine PET, a molecular imaging technique that detects functionally active tumors, is useful for further evaluating MRI changes concerning for tumor recurrence during routine surveillance. Methods : Using11 C-methionine PET during follow-up visits, we evaluated 27 lesions in 26 patients with new or worsening MRI abnormalities for whom tumor recurrence was of concern. We performed quantitative and qualitative assessments of both11 C-methionine PET and MRI data to predict the presence of tumor recurrence. Further, to assess for an association with overall survival (OS), we plotted the time from development of the imaging changes against survival. Results: Qualitative evaluation of11 C-methionine PET achieved 100% sensitivity, 60% specificity, and 93% accuracy to correctly predict the presence of tumors in 27 new or worsening MRI abnormalities. Qualitative MRI evaluation achieved sensitivity ranging from 86% to 95%, specificity ranging from 40% to 60%, and accuracy ranging from 85% to 89%. The interobserver agreement for11 C-methionine PET assessment was 100%, whereas the interobserver agreement was only 50% for MRI ( P < 0.01). Quantitative MRI and11 C-methionine PET evaluation using receiver-operating characteristics demonstrated higher specificity (80%) than did qualitative evaluations (40%-60%). Postcontrast enhancement volume, metabolic tumor volume, tumor-to-brain ratio, and presence of tumor as determined by consensus MRI assessment were inversely associated with OS. Conclusion:11 C-methionine PET has slightly higher sensitivity and accuracy for correctly predicting tumor recurrence, with excellent interobserver agreement, than does MRI. Quantitative11 C-methionine PET can also predict OS. These findings suggest that11 C-methionine PET can be useful for further evaluation of MRI changes during surveillance of previously treated PHGGs., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)- Published
- 2022
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23. The Yin and Yang of Targeting KLRG1 + Tregs and Effector Cells.
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Borys SM, Bag AK, Brossay L, and Adeegbe DO
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- Autoimmunity, CD8-Positive T-Lymphocytes, T-Lymphocytes, Regulatory
- Abstract
The literature surrounding KLRG1 has primarily focused on NK and CD8
+ T cells. However, there is evidence that the most suppressive Tregs express KLRG1. Until now, the role of KLRG1 on Tregs has been mostly overlooked and remains to be elucidated. Here we review the current literature on KLRG1 with an emphasis on the KLRG1+ Treg subset role during cancer development and autoimmunity. KLRG1 has been recently proposed as a new checkpoint inhibitor target, but these studies focused on the effects of KLRG1 blockade on effector cells. We propose that when designing anti-tumor therapies targeting KLRG1, the effects on both effector cells and Tregs will have to be considered., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Borys, Bag, Brossay and Adeegbe.)- Published
- 2022
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24. Radiohistogenomics of pediatric low-grade neuroepithelial tumors.
- Author
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Bag AK, Chiang J, and Patay Z
- Subjects
- Child, Humans, Mutation, Prognosis, Brain Neoplasms diagnostic imaging, Brain Neoplasms genetics, Central Nervous System Neoplasms, Glioma, Neoplasms, Neuroepithelial diagnostic imaging, Neoplasms, Neuroepithelial genetics
- Abstract
Purpose: In addition to histology, genetic alteration is now required to classify many central nervous system (CNS) tumors according to the most recent World Health Organization CNS tumor classification scheme. Although that is still not the case for classifying pediatric low-grade neuroepithelial tumors (PLGNTs), genetic and molecular features are increasingly being used for making treatment decisions. This approach has become a standard clinical practice in many specialized pediatric cancer centers and will likely be more widely practiced in the near future. This paradigm shift in the management of PLGNTs necessitates better understanding of how genetic alterations influence histology and imaging characteristics of individual PLGNT phenotypes., Methods: The complex association of genetic alterations with histology, clinical, and imaging of each phenotype of the extremely heterogeneous PLGNT family has been addressed in a holistic approach in this up-to-date review article. A new imaging stratification scheme has been proposed based on tumor morphology, location, histology, and genetics. Imaging characteristics of each PLGNT entity are also depicted in light of histology and genetics., Conclusion: This article reviews the association of specific genetic alteration with location, histology, imaging, and prognosis of a specific tumor of the PLGNT family and how that information can be used for better imaging of these tumors., (© 2021. The Author(s).)
- Published
- 2021
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25. A rare manifestation of choriocarcinoma syndrome in a child with primary intracranial germ cell tumor and extracranial metastases: A case report and review of the literature.
- Author
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Keenan C, Ramirez N, Elijovich L, Klimo P Jr, Bag AK, Acharya S, and Upadhyaya SA
- Subjects
- Brain Neoplasms drug therapy, Child, Choriocarcinoma drug therapy, Female, Hemorrhage pathology, Humans, Ischemic Stroke pathology, Lung Neoplasms drug therapy, Neoplasms, Germ Cell and Embryonal drug therapy, Uterine Neoplasms drug therapy, Brain Neoplasms pathology, Choriocarcinoma pathology, Lung Neoplasms secondary, Neoplasms, Germ Cell and Embryonal pathology, Uterine Neoplasms pathology
- Abstract
Choriocarcinoma syndrome is an uncommon, potentially fatal complication of germ cell tumors (GCTs) in adults, but it is not well documented in children. Pediatric central nervous system (CNS) GCTs comprise a rare group of malignancies not usually associated with extra-CNS metastatic disease. Here, we report the case of a pediatric patient with a suprasellar mixed GCT and pulmonary metastases who presented with intratumoral hemorrhage and stroke. Choriocarcinoma syndrome developed soon after initiating chemotherapy. The primary tumor and pulmonary metastases were successfully treated using a multidisciplinary approach, including neurovascular intervention, chemotherapy, and craniospinal irradiation., (© 2021 Wiley Periodicals LLC.)
- Published
- 2021
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26. Haemophagocytic lymphohistiocytosis restricted to the central nervous system.
- Author
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Bhoopalan SV, Campbell PK, Bag AK, Onciu M, and Srinivasan A
- Abstract
Competing Interests: Competing interests: None declared.
- Published
- 2021
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27. Tumor- and osteoclast-derived NRP2 in prostate cancer bone metastases.
- Author
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Polavaram NS, Dutta S, Islam R, Bag AK, Roy S, Poitz D, Karnes J, Hofbauer LC, Kohli M, Costello BA, Jimenez R, Batra SK, Teply BA, Muders MH, and Datta K
- Abstract
Understanding the role of neuropilin 2 (NRP2) in prostate cancer cells as well as in the bone microenvironment is pivotal in the development of an effective targeted therapy for the treatment of prostate cancer bone metastasis. We observed a significant upregulation of NRP2 in prostate cancer cells metastasized to bone. Here, we report that targeting NRP2 in cancer cells can enhance taxane-based chemotherapy with a better therapeutic outcome in bone metastasis, implicating NRP2 as a promising therapeutic target. Since, osteoclasts present in the tumor microenvironment express NRP2, we have investigated the potential effect of targeting NRP2 in osteoclasts. Our results revealed NRP2 negatively regulates osteoclast differentiation and function in the presence of prostate cancer cells that promotes mixed bone lesions. Our study further delineated the molecular mechanisms by which NRP2 regulates osteoclast function. Interestingly, depletion of NRP2 in osteoclasts in vivo showed a decrease in the overall prostate tumor burden in the bone. These results therefore indicate that targeting NRP2 in prostate cancer cells as well as in the osteoclastic compartment can be beneficial in the treatment of prostate cancer bone metastasis.
- Published
- 2021
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28. Oncolytic HSV-1 G207 Immunovirotherapy for Pediatric High-Grade Gliomas.
- Author
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Friedman GK, Johnston JM, Bag AK, Bernstock JD, Li R, Aban I, Kachurak K, Nan L, Kang KD, Totsch S, Schlappi C, Martin AM, Pastakia D, McNall-Knapp R, Farouk Sait S, Khakoo Y, Karajannis MA, Woodling K, Palmer JD, Osorio DS, Leonard J, Abdelbaki MS, Madan-Swain A, Atkinson TP, Whitley RJ, Fiveash JB, Markert JM, and Gillespie GY
- Subjects
- Adolescent, Brain Neoplasms diagnostic imaging, Brain Neoplasms pathology, Brain Neoplasms radiotherapy, Child, Child, Preschool, Combined Modality Therapy, Female, Glioma diagnostic imaging, Glioma pathology, Glioma radiotherapy, Humans, Kaplan-Meier Estimate, Killer Cells, Natural, Leukocyte Count, Male, T-Lymphocytes, Brain Neoplasms therapy, Glioma therapy, Oncolytic Virotherapy adverse effects
- Abstract
Background: Outcomes in children and adolescents with recurrent or progressive high-grade glioma are poor, with a historical median overall survival of 5.6 months. Pediatric high-grade gliomas are largely immunologically silent or "cold," with few tumor-infiltrating lymphocytes. Preclinically, pediatric brain tumors are highly sensitive to oncolytic virotherapy with genetically engineered herpes simplex virus type 1 (HSV-1) G207, which lacks genes essential for replication in normal brain tissue., Methods: We conducted a phase 1 trial of G207, which used a 3+3 design with four dose cohorts of children and adolescents with biopsy-confirmed recurrent or progressive supratentorial brain tumors. Patients underwent stereotactic placement of up to four intratumoral catheters. The following day, they received G207 (10
7 or 108 plaque-forming units) by controlled-rate infusion over a period of 6 hours. Cohorts 3 and 4 received radiation (5 Gy) to the gross tumor volume within 24 hours after G207 administration. Viral shedding from saliva, conjunctiva, and blood was assessed by culture and polymerase-chain-reaction assay. Matched pre- and post-treatment tissue samples were examined for tumor-infiltrating lymphocytes by immunohistologic analysis., Results: Twelve patients 7 to 18 years of age with high-grade glioma received G207. No dose-limiting toxic effects or serious adverse events were attributed to G207 by the investigators. Twenty grade 1 adverse events were possibly related to G207. No virus shedding was detected. Radiographic, neuropathological, or clinical responses were seen in 11 patients. The median overall survival was 12.2 months (95% confidence interval, 8.0 to 16.4); as of June 5, 2020, a total of 4 of 11 patients were still alive 18 months after G207 treatment. G207 markedly increased the number of tumor-infiltrating lymphocytes., Conclusions: Intratumoral G207 alone and with radiation had an acceptable adverse-event profile with evidence of responses in patients with recurrent or progressive pediatric high-grade glioma. G207 converted immunologically "cold" tumors to "hot." (Supported by the Food and Drug Administration and others; ClinicalTrials.gov number, NCT02457845.)., (Copyright © 2021 Massachusetts Medical Society.)- Published
- 2021
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29. Design and Rationale for First-in-Human Phase 1 Immunovirotherapy Clinical Trial of Oncolytic HSV G207 to Treat Malignant Pediatric Cerebellar Brain Tumors.
- Author
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Bernstock JD, Bag AK, Fiveash J, Kachurak K, Elsayed G, Chagoya G, Gessler F, Valdes PA, Madan-Swain A, Whitley R, Markert JM, Gillespie GY, Johnston JM, and Friedman GK
- Subjects
- Adolescent, Cerebellar Neoplasms immunology, Cerebellar Neoplasms pathology, Child, Child, Preschool, Clinical Trials, Phase I as Topic, Cohort Studies, Combined Modality Therapy, Female, Humans, Male, Virus Replication, Cerebellar Neoplasms therapy, Oncolytic Virotherapy methods, Radiotherapy methods, Simplexvirus genetics
- Abstract
Brain tumors represent the most common pediatric solid neoplasms and leading cause of childhood cancer-related morbidity and mortality. Although most adult brain tumors are supratentorial and arise in the cerebrum, the majority of pediatric brain tumors are infratentorial and arise in the posterior fossa, specifically the cerebellum. Outcomes from malignant cerebellar tumors are unacceptable despite aggressive treatments (surgery, radiation, and/or chemotherapy) that are harmful to the developing brain. Novel treatments/approaches such as oncolytic virotherapy are urgently needed. Preclinical and prior clinical studies suggest that genetically engineered oncolytic herpes simplex virus (HSV-1) G207 can safely target cerebellar malignancies and has potential to induce an antitumor immune response at local and distant sites of disease, including spinal metastases and leptomeningeal disease. Herein, we outline the rationale, design, and significance of a first-in-human immunotherapy Phase 1 clinical trial targeting recurrent cerebellar malignancies with HSV G207 combined with a single low-dose of radiation (5 Gy), designed to enhance virus replication and innate and adaptive immune responses. We discuss the unique challenges of inoculating virus through intratumoral catheters into cerebellar tumors. The trial utilizes a single arm open-label traditional 3 + 3 design with four dose cohorts. The primary objective is to assess safety and tolerability of G207 with radiation in recurrent/progressive malignant pediatric cerebellar tumors. After biopsy to prove recurrence/progression, one to four intratumoral catheters will be placed followed by a controlled-rate infusion of G207 for 6 h followed by the removal of catheters at the bedside. Radiation will be given within 24 h of virus inoculation. Patients will be monitored closely for toxicity and virus shedding. Efficacy will be assessed by measuring radiographic response, performance score, progression-free and overall survival, and quality of life. The data obtained will be invaluable in our efforts to produce more effective and less toxic therapies for children with high-grade brain tumors.
- Published
- 2020
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30. Response assessment in paediatric low-grade glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.
- Author
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Fangusaro J, Witt O, Hernáiz Driever P, Bag AK, de Blank P, Kadom N, Kilburn L, Lober RM, Robison NJ, Fisher MJ, Packer RJ, Young Poussaint T, Papusha L, Avula S, Brandes AA, Bouffet E, Bowers D, Artemov A, Chintagumpala M, Zurakowski D, van den Bent M, Bison B, Yeom KW, Taal W, and Warren KE
- Subjects
- Age of Onset, Central Nervous System Neoplasms epidemiology, Central Nervous System Neoplasms pathology, Child, Consensus, Female, Glioma epidemiology, Glioma pathology, Humans, Magnetic Resonance Imaging standards, Male, Neoplasm Grading, Perfusion Imaging standards, Positron-Emission Tomography standards, Predictive Value of Tests, Time Factors, Treatment Outcome, Tumor Burden, Central Nervous System Neoplasms diagnostic imaging, Central Nervous System Neoplasms therapy, Endpoint Determination standards, Glioma diagnostic imaging, Glioma therapy, Neuroimaging standards
- Abstract
Paediatric low-grade gliomas (also known as pLGG) are the most common type of CNS tumours in children. In general, paediatric low-grade gliomas show clinical and biological features that are distinct from adult low-grade gliomas, and the developing paediatric brain is more susceptible to toxic late effects of the tumour and its treatment. Therefore, response assessment in children requires additional considerations compared with the adult Response Assessment in Neuro-Oncology criteria. There are no standardised response criteria in paediatric clinical trials, which makes it more difficult to compare responses across studies. The Response Assessment in Pediatric Neuro-Oncology working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. We established a subcommittee to develop consensus recommendations for response assessment in paediatric low-grade gliomas. Final recommendations were based on literature review, current practice, and expert opinion of working group members. Consensus recommendations include imaging response assessments, with additional guidelines for visual functional outcomes in patients with optic pathway tumours. As with previous consensus recommendations, these recommendations will need to be validated in prospective clinical trials., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
- Full Text
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31. "Code-Stroke" CT Perfusion; Challenges and Pitfalls.
- Author
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Sotoudeh H, Bag AK, and Brooks MD
- Subjects
- Humans, Treatment Outcome, Brain Ischemia diagnosis, Perfusion Imaging methods, Surgery, Computer-Assisted methods, Thrombectomy methods, Tomography, X-Ray Computed methods
- Abstract
Rationale and Objectives: Regarding the most recent ischemic stroke treatment guideline, perfusion imaging has been recommended up to 24 hours after initial symptoms of brain infarction. Patients with a significant amount of salvageable peri-infarct ischemia and no contraindications benefit from delayed thrombolysis and intra-arterial thrombectomy. This approach causes increasingly more CT perfusion to be done in the subacute phase of ischemic stroke. CT perfusion findings in this "subacute phase" are slightly different from "hyper-acute" ischemic stroke. The interpreting radiologist must be confident in reporting the CT perfusion study in an urgent setting since these studies are under the umbrella of "code-stroke" and should be read in minutes. In addition, results of the CT perfusion have a critical effect on the patient's outcome and misinterpretation can be fatal in that underestimation of the salvageable ischemia excludes the patient from potential effective treatment. Underestimation of infarct volume may cause unnecessary thrombolysis/thrombectomy and potentially fatal intracranial hemorrhage., Materials and Methods: In this review, we are trying to explain the basic concept of "code-stroke" CT perfusion, typical findings, and pitfalls in a practical way., (Copyright © 2019 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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32. A novel in situ multiplex immunofluorescence panel for the assessment of tumor immunopathology and response to virotherapy in pediatric glioblastoma reveals a role for checkpoint protein inhibition.
- Author
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Bernstock JD, Vicario N, Rong L, Valdes PA, Choi BD, Chen JA, DiToro D, Osorio DS, Kachurak K, Gessler F, Johnston JM Jr, Atkinson TP, Whitley RJ, Bag AK, Gillespie GY, Markert JM, Maric D, and Friedman GK
- Abstract
Immunotherapy with oncolytic herpes simplex virus-1 therapy offers an innovative, targeted, less-toxic approach for treating brain tumors. However, a major obstacle in maximizing oncolytic virotherapy is a lack of comprehensive understanding of the underlying mechanisms that unfold in CNS tumors/associated microenvironments after infusion of virus. We demonstrate that our multiplex biomarker screening platform comprehensively informs changes in both topographical location and functional states of resident/infiltrating immune cells that play a role in neuropathology after treatment with HSV G207 in a pediatric Phase 1 patient. Using this approach, we identified robust infiltration of CD8
+ T cells suggesting activation of the immune response following virotherapy; however there was a corresponding upregulation of checkpoint proteins PD-1, PD-L1, CTLA-4, and IDO revealing a potential role for checkpoint inhibitors. Such work may ultimately lead to an understanding of the governing pathobiology of tumors, thereby fostering development of novel therapeutics tailored to produce optimal responses., (© 2019 The Author(s). Published with license by Taylor & Francis Group, LLC.)- Published
- 2019
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33. Connecting signaling and metabolic pathways in EGF receptor-mediated oncogenesis of glioblastoma.
- Author
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Bag AK, Mandloi S, Jarmalavicius S, Mondal S, Kumar K, Mandal C, Walden P, Chakrabarti S, and Mandal C
- Subjects
- Brain Neoplasms etiology, Brain Neoplasms genetics, Carcinogenesis, Cell Line, Tumor, Computational Biology, Computer Simulation, ErbB Receptors genetics, ErbB Receptors metabolism, Glioblastoma etiology, Glioblastoma genetics, Humans, Metabolic Networks and Pathways, Models, Biological, Mutation, Protein Interaction Maps, Signal Transduction, Systems Biology, Brain Neoplasms metabolism, Glioblastoma metabolism
- Abstract
As malignant transformation requires synchronization of growth-driving signaling (S) and metabolic (M) pathways, defining cancer-specific S-M interconnected networks (SMINs) could lead to better understanding of oncogenic processes. In a systems-biology approach, we developed a mathematical model for SMINs in mutated EGF receptor (EGFRvIII) compared to wild-type EGF receptor (EGFRwt) expressing glioblastoma multiforme (GBM). Starting with experimentally validated human protein-protein interactome data for S-M pathways, and incorporating proteomic data for EGFRvIII and EGFRwt GBM cells and patient transcriptomic data, we designed a dynamic model for EGFR-driven GBM-specific information flow. Key nodes and paths identified by in silico perturbation were validated experimentally when inhibition of signaling pathway proteins altered expression of metabolic proteins as predicted by the model. This demonstrated capacity of the model to identify unknown connections between signaling and metabolic pathways, explain the robustness of oncogenic SMINs, predict drug escape, and assist identification of drug targets and the development of combination therapies., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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34. Current and Future Imaging Methods for Evaluating Response to Immunotherapy in Neuro-Oncology.
- Author
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Kasten BB, Udayakumar N, Leavenworth JW, Wu AM, Lapi SE, McConathy JE, Sorace AG, Bag AK, Markert JM, and Warram JM
- Subjects
- Animals, Humans, Magnetic Resonance Imaging methods, Nervous System Neoplasms therapy, Theranostic Nanomedicine trends, Immunotherapy methods, Nervous System Neoplasms diagnostic imaging, Positron-Emission Tomography methods, Theranostic Nanomedicine methods
- Abstract
Imaging plays a central role in evaluating responses to therapy in neuro-oncology patients. The advancing clinical use of immunotherapies has demonstrated that treatment-related inflammatory responses mimic tumor growth via conventional imaging, thus spurring the development of new imaging approaches to adequately distinguish between pseudoprogression and progressive disease. To this end, an increasing number of advanced imaging techniques are being evaluated in preclinical and clinical studies. These novel molecular imaging approaches will serve to complement conventional response assessments during immunotherapy. The goal of these techniques is to provide definitive metrics of tumor response at earlier time points to inform treatment decisions, which has the potential to improve patient outcomes. This review summarizes the available immunotherapy regimens, clinical response criteria, current state-of-the-art imaging approaches, and groundbreaking strategies for future implementation to evaluate the anti-tumor and immune responses to immunotherapy in neuro-oncology applications., Competing Interests: Competing Interests: Anna Wu is a founder, board member, and consultant to ImaginAb, Inc., and a consultant to Avidity Biosciences. James Markert has received funding from a structured buyout of Catherex, Inc., and holds <8% equity interest in Aettis, Inc. Both companies had/have interests in oncolytic virotherapy.
- Published
- 2019
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35. Diagnosing growth in low-grade gliomas with and without longitudinal volume measurements: A retrospective observational study.
- Author
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Fathallah-Shaykh HM, DeAtkine A, Coffee E, Khayat E, Bag AK, Han X, Warren PP, Bredel M, Fiveash J, Markert J, Bouaynaya N, and Nabors LB
- Subjects
- Brain Neoplasms pathology, Female, Glioma pathology, Humans, Longitudinal Studies, Male, Middle Aged, Neoplasm Grading, Neoplasm Invasiveness, Predictive Value of Tests, Retrospective Studies, Time Factors, Tumor Burden, Brain Neoplasms diagnostic imaging, Cell Proliferation, Glioma diagnostic imaging, Magnetic Resonance Imaging
- Abstract
Background: Low-grade gliomas cause significant neurological morbidity by brain invasion. There is no universally accepted objective technique available for detection of enlargement of low-grade gliomas in the clinical setting; subjective evaluation by clinicians using visual comparison of longitudinal radiological studies is the gold standard. The aim of this study is to determine whether a computer-assisted diagnosis (CAD) method helps physicians detect earlier growth of low-grade gliomas., Methods and Findings: We reviewed 165 patients diagnosed with grade 2 gliomas, seen at the University of Alabama at Birmingham clinics from 1 July 2017 to 14 May 2018. MRI scans were collected during the spring and summer of 2018. Fifty-six gliomas met the inclusion criteria, including 19 oligodendrogliomas, 26 astrocytomas, and 11 mixed gliomas in 30 males and 26 females with a mean age of 48 years and a range of follow-up of 150.2 months (difference between highest and lowest values). None received radiation therapy. We also studied 7 patients with an imaging abnormality without pathological diagnosis, who were clinically stable at the time of retrospective review (14 May 2018). This study compared growth detection by 7 physicians aided by the CAD method with retrospective clinical reports. The tumors of 63 patients (56 + 7) in 627 MRI scans were digitized, including 34 grade 2 gliomas with radiological progression and 22 radiologically stable grade 2 gliomas. The CAD method consisted of tumor segmentation, computing volumes, and pointing to growth by the online abrupt change-of-point method, which considers only past measurements. Independent scientists have evaluated the segmentation method. In 29 of the 34 patients with progression, the median time to growth detection was only 14 months for CAD compared to 44 months for current standard of care radiological evaluation (p < 0.001). Using CAD, accurate detection of tumor enlargement was possible with a median of only 57% change in the tumor volume as compared to a median of 174% change of volume necessary to diagnose tumor growth using standard of care clinical methods (p < 0.001). In the radiologically stable group, CAD facilitated growth detection in 13 out of 22 patients. CAD did not detect growth in the imaging abnormality group. The main limitation of this study was its retrospective design; nevertheless, the results depict the current state of a gold standard in clinical practice that allowed a significant increase in tumor volumes from baseline before detection. Such large increases in tumor volume would not be permitted in a prospective design. The number of glioma patients (n = 56) is a limitation; however, it is equivalent to the number of patients in phase II clinical trials., Conclusions: The current practice of visual comparison of longitudinal MRI scans is associated with significant delays in detecting growth of low-grade gliomas. Our findings support the idea that physicians aided by CAD detect growth at significantly smaller volumes than physicians using visual comparison alone. This study does not answer the questions whether to treat or not and which treatment modality is optimal. Nonetheless, early growth detection sets the stage for future clinical studies that address these questions and whether early therapeutic interventions prolong survival and improve quality of life., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: HFS and NB are co-founders of MRIMATH LLC. LBN serves on the scientific advisory boards for Abbvie, Blue Earth Diagnostics, Karyopharm, and Kiyatec and the Data safety and monitoring board for UPENN and Ziopharm. JM is 1) the Recipient of funds related to structured buyout of an oncolytic virus company, Catherex, Inc, by Amgen. 2) Equity holder in an oncolytic virus company, Treovor, Inc. 3) Equity holder in an oncolytic virus company, Aettis, Inc. 4) Board Member, UAB Health System and UAB Health Services Foundation. 5) Research grant holder from NIH and Gateway to conduct clinical trials for malignant glioma using oncolytic viruses. these funding sources were not involved in the study under submission. 6) Employment: UAB SOM and UAB Health Services Foundation. 7) Patent applications for oncolytic virus and administration techniques thereof not applicable to this paper.
- Published
- 2019
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36. Stereotactic Placement of Intratumoral Catheters for Continuous Infusion Delivery of Herpes Simplex Virus -1 G207 in Pediatric Malignant Supratentorial Brain Tumors.
- Author
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Bernstock JD, Wright Z, Bag AK, Gessler F, Gillespie GY, Markert JM, Friedman GK, and Johnston JM
- Subjects
- Adolescent, Child, Female, Herpesvirus 1, Human genetics, Humans, Magnetic Resonance Imaging, Male, Neoplasm Recurrence, Local diagnostic imaging, Oncolytic Viruses, Postoperative Complications, Supratentorial Neoplasms diagnostic imaging, Catheters, Indwelling, Neoplasm Recurrence, Local therapy, Oncolytic Virotherapy methods, Stereotaxic Techniques, Supratentorial Neoplasms therapy
- Abstract
Objective: The engineered herpes simplex virus-1 G207, is a promising therapeutic option for central nervous system tumors. The first-ever pediatric phase 1 trial of continuous-infusion delivery of G207 via intratumoral catheters for recurrent or progressive malignant brain tumors is ongoing. In this article, we describe surgical techniques for the accurate placement of catheters in multiple supratentorial locations and perioperative complications associated with such procedures., Methods: A prospective study of G207 in children with recurrent malignant supratentorial tumors is ongoing. Preoperative stereotactic protocol magnetic resonance imaging was performed, and catheter trajectories planned using StealthStation planning software. Children underwent placement of 3-4 silastic catheters using a small incision burr hole and the Vertek system. Patients had a preinfusion computed tomography scan to confirm correct placement of catheters., Results: Six children underwent implantation of 3-4 catheters. Locations of catheter placement included frontal, temporal, parietal, and occipital lobes, and the insula and thalamus. There were no clinically significant perioperative complications. Postoperative computed tomography scans coupled with preoperative MRI scans demonstrated accurate placement of 21 of 22 catheters, with 1 misplaced catheter pulled back to an optimal location at the bedside. One patient had hemorrhage along the catheter tract that was clinically asymptomatic. Another patient had cerebrospinal fluid leak from a biopsy incision 9 days after surgery that was oversewn without complication., Conclusions: The placement of multiple intratumoral catheters in pediatric patients with supratentorial tumors via frameless stereotactic techniques is feasible and safe. Intratumoral catheters provide a potentially effective route for the delivery of G207 and may be employed in other trials utilizing oncolytic virotherapy for brain tumors., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2019
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37. Macrophage-Derived Neuropilin-2 Exhibits Novel Tumor-Promoting Functions.
- Author
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Roy S, Bag AK, Dutta S, Polavaram NS, Islam R, Schellenburg S, Banwait J, Guda C, Ran S, Hollingsworth MA, Singh RK, Talmadge JE, Muders MH, Batra SK, and Datta K
- Subjects
- Animals, Apoptosis, Cell Line, Tumor, Cells, Cultured, Humans, Immune System, Immunosuppression Therapy, Immunotherapy, Jurkat Cells, Leukocytes, Mononuclear cytology, Macrophages cytology, Mice, Mice, Inbred C57BL, Monocytes cytology, Neoplasms therapy, Phagocytosis, Phagosomes metabolism, Signal Transduction, Transcriptome, Tumor Microenvironment, Gene Expression Regulation, Neoplastic, Macrophages metabolism, Neoplasms immunology, Neuropilin-2 metabolism
- Abstract
Tumor-associated macrophages (TAM) are causally associated with tumorigenesis as well as regulation of antitumor immune responses and have emerged as potential immunotherapeutic targets. Recent evidence suggests TAM phagocytose apoptotic tumor cells within the tumor microenvironment through efferocytosis in an immunologically silent manner, thus maintaining an immunosuppressed microenvironment. The signal transduction pathways coupling efferocytosis and immunosuppression are not well known. Neuropilin-2 (NRP2) is a member of the membrane-associated neuropilin family and has been reported in different immune cells but is poorly characterized. In this study, we show that NRP2 is expressed during macrophage differentiation, is induced by tumor cells, and regulates phagocytosis in macrophages. Furthermore, NRP2 in TAM promoted efferocytosis and facilitated tumor growth. Deletion of NRP2 from TAM impaired the clearance of apoptotic tumor cells and increased secondary necrosis within tumors. This resulted in a break in the immune tolerance and reinitiated antitumor immune responses, characterized by robust infiltration of CD8
+ T and natural killer cells. This result suggests NRP2 may act as a molecular mediator that connects efferocytosis and immune suppression. Deletion of NRP2 in TAM downregulated several immunosuppressive and tumor-promoting genes and upregulated immunostimulatory genes in the myeloid compartment. Taken together, our study demonstrates that TAM-derived NRP2 plays a crucial role in tumor promotion through efferocytosis, opening the enticing option for the development of effective immunotherapy targeting TAM. Significance: Neuropilin-2 in macrophages promotes tumor growth by regulating efferocytosis of apoptotic tumor cells and orchestrating immune suppression. Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/19/5600/F1.large.jpg Cancer Res; 78(19); 5600-17. ©2018 AACR ., (©2018 American Association for Cancer Research.)- Published
- 2018
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38. Pediatric Skeletal Scintigraphy: What a General Radiologist Needs to Know.
- Author
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Palot Manzil FF, Baldwin J, and Bag AK
- Subjects
- Child, Diagnosis, Differential, Humans, Radiopharmaceuticals, Bone Diseases diagnostic imaging, Positron-Emission Tomography methods
- Abstract
Pediatric skeletal scintigraphy is a noninvasive imaging modality which aids in functional as well as anatomic evaluation of bone. Bone scintigraphy plays a major role in diagnosis and evaluation of various benign, primary malignant and metastatic pediatric bone pathologies. The advantage of bone scan is that it becomes positive well before the bone pathology is evident on radiographs and specifically the entire skeleton can be imaged in a single examination. Pediatric bone scintigraphy evaluation can be challenging to the general radiologist not routinely exposed to the study, as the growing skeleton is quite different from a mature skeleton especially at or near the growth plates. Though nonspecific, bone scintigraphy is a very sensitive modality. Correlation with a good history and other imaging modalities like radiographs, computed tomography and magnetic resonance imaging helps in diagnosis., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
39. Imaging of Inflammatory Disorders of Salivary Glands.
- Author
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Bag AK, Curé JK, Chapman PR, Singhal A, and Haneef Mohamed AW
- Subjects
- Humans, Magnetic Resonance Imaging methods, Salivary Glands diagnostic imaging, Sialadenitis diagnostic imaging, Tomography, X-Ray Computed methods
- Abstract
Sialadenitis is among the most common conditions that affect the salivary glands. Inflammation of the salivary glands occurs as the end result of a variety of pathologic conditions, including infectious, autoimmune, and idiopathic causes. Clinically, inflammation of the salivary gland causes pain and localized swelling. The presentation may be acute or chronic, and can be recurrent. Because there is significant overlap of underlying disease mechanisms and clinical presentations, radiologic evaluation often plays a significant role in evaluation. This article is a brief review of sialadenitis, including disease mechanisms, causes, and the practical imaging of the salivary glands., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
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40. Multifaceted Role of Neuropilins in the Immune System: Potential Targets for Immunotherapy.
- Author
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Roy S, Bag AK, Singh RK, Talmadge JE, Batra SK, and Datta K
- Abstract
Neuropilins (NRPs) are non-tyrosine kinase cell surface glycoproteins expressed in all vertebrates and widely conserved across species. The two isoforms, such as neuropilin-1 (NRP1) and neuropilin-2 (NRP2), mainly act as coreceptors for class III Semaphorins and for members of the vascular endothelial growth factor family of molecules and are widely known for their role in a wide array of physiological processes, such as cardiovascular, neuronal development and patterning, angiogenesis, lymphangiogenesis, as well as various clinical disorders. Intriguingly, additional roles for NRPs occur with myeloid and lymphoid cells, in normal physiological as well as different pathological conditions, including cancer, immunological disorders, and bone diseases. However, little is known concerning the molecular pathways that govern these functions. In addition, NRP1 expression has been characterized in different immune cellular phenotypes including macrophages, dendritic cells, and T cell subsets, especially regulatory T cell populations. By contrast, the functions of NRP2 in immune cells are less well known. In this review, we briefly summarize the genomic organization, structure, and binding partners of the NRPs and extensively discuss the recent advances in their role and function in different immune cell subsets and their clinical implications.
- Published
- 2017
- Full Text
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41. Perfusion MRI Can Impact Treatment Decision in Ictal-Interictal Continuum.
- Author
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Venkatraman A, Khawaja A, Bag AK, Mirza M, Szaflarski JP, and Pati SBB
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Epilepsy diagnostic imaging, Magnetic Resonance Angiography methods
- Abstract
Lateralized periodic discharges (LPDs) are commonly seen on EEG in critically ill patients. They are often associated with seizures, but some patients may have them without seizures. Therefore, they are considered to lie in the ictal-interictal continuum. When ictal, they require multiple antiepileptic drugs to treat effectively, which can expose the patient to iatrogenic complications. Therefore, optimal management is controversial. We present here two cases where perfusion-weighted MRI was useful in distinguishing ictal from interictal LPDs. In the first patient, hyperperfusion in the area showing LPDs was considered an indication that the LPDs were ictal, and aggressive treatment led to clinical improvement. The second patient had no asymmetry on perfusion-weighted MRI, and therefore, we did not escalate antiepileptic therapy, and the LPDs resolved spontaneously over the next few days. Perfusion-weighted MRI offers several advantages over other techniques, such as single-photon emission computerized tomography that have been used for this purpose before. It does not expose the patient to radiation, and newer techniques like arterial spin labeling can even obviate the need for intravenous contrast. Larger scale studies using perfusion-weighted MRI will be of great value to clinical practice.
- Published
- 2017
- Full Text
- View/download PDF
42. Repeatability of 18 F-FLT PET in a Multicenter Study of Patients with High-Grade Glioma.
- Author
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Lodge MA, Holdhoff M, Leal JP, Bag AK, Nabors LB, Mintz A, Lesser GJ, Mankoff DA, Desai AS, Mountz JM, Lieberman FS, Fisher JD, Desideri S, Ye X, Grossman SA, Schiff D, and Wahl RL
- Subjects
- Adult, Female, Humans, Image Interpretation, Computer-Assisted methods, Male, Middle Aged, Neoplasm Grading, Observer Variation, Radiopharmaceuticals, Reproducibility of Results, Sensitivity and Specificity, United States, Brain Neoplasms diagnostic imaging, Brain Neoplasms pathology, Dideoxynucleosides, Glioma diagnostic imaging, Glioma pathology, Positron-Emission Tomography methods
- Abstract
Quantitative 3'-deoxy-3'-
18 F-fluorothymidine (18 F-FLT) PET has potential as a noninvasive tumor biomarker for the objective assessment of response to treatment. To guide interpretation of these quantitative data, we evaluated the repeatability of18 F-FLT PET as part of a multicenter trial involving patients with high-grade glioma. Methods:18 F-FLT PET was performed on 10 patients with recurrent high-grade glioma at 5 different institutions within the Adult Brain Tumor Consortium trial ABTC1101. Data were acquired according to a double baseline protocol in which PET examinations were repeated within 2 d of each other with no intervening treatment. On each of the 2 imaging days, dedicated brain PET was performed at 2 time points, 1 and 3 h after18 F-FLT administration. Tumor SUVs and related parameters were measured at a central laboratory using various volumes of interest: isocontour at 30% of the maximum pixel (SUVmean_30% ), gradient-based segmentation (SUVmean_gradient ), the maximum pixel (SUVmax ), and a 1-mL sphere at the region of highest uptake (SUVpeak ). Repeatability coefficients (RCs) were calculated from the relative differences between corresponding SUV measurements obtained on the 2 d. Results: RCs for tumor SUVs were 22.5% (SUVmean_30% ), 23.8% (SUVmean_gradient ), 23.2% (SUVmax ), and 18.5% (SUVpeak ) at 1 h after injection. Corresponding data at 3 h were 22.4%, 25.0%, 27.3%, and 23.6%. Normalizing the tumor SUV data with reference to a background region improved repeatability, and the most stable parameter was the tumor-to-background ratio derived using SUVpeak (RC, 16.5%). Conclusion: SUV quantification of18 F-FLT uptake in glioma had an RC in the range of 18%-24% when imaging began 1 h after18 F-FLT administration. The volume-of-interest methodology had a small but not negligible influence on repeatability, with the best performance obtained using SUVpeak Although changes in18 F-FLT SUV after treatment cannot be directly interpreted as a change in tumor proliferation, we have established ranges beyond which SUV differences are likely due to legitimate biologic effects., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)- Published
- 2017
- Full Text
- View/download PDF
43. Rationale and Design of a Phase 1 Clinical Trial to Evaluate HSV G207 Alone or with a Single Radiation Dose in Children with Progressive or Recurrent Malignant Supratentorial Brain Tumors.
- Author
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Waters AM, Johnston JM, Reddy AT, Fiveash J, Madan-Swain A, Kachurak K, Bag AK, Gillespie GY, Markert JM, and Friedman GK
- Subjects
- Adolescent, Adult, Brain Neoplasms genetics, Brain Neoplasms radiotherapy, Brain Neoplasms virology, Child, Child, Preschool, Female, Genetic Therapy, Humans, Male, Neoplasm Recurrence, Local genetics, Neoplasm Recurrence, Local radiotherapy, Neoplasm Recurrence, Local virology, Oncolytic Viruses genetics, Safety, Supratentorial Neoplasms virology, Genetic Vectors administration & dosage, Herpesvirus 1, Human genetics, Oncolytic Virotherapy, Research Design, Supratentorial Neoplasms genetics, Supratentorial Neoplasms radiotherapy
- Abstract
Primary central nervous system tumors are the most common solid neoplasm of childhood and the leading cause of cancer-related death in pediatric patients. Survival rates for children with malignant supratentorial brain tumors are poor despite aggressive treatment with combinations of surgery, radiation, and chemotherapy, and survivors often suffer from damaging lifelong sequelae from current therapies. Novel innovative treatments are greatly needed. One promising new approach is the use of a genetically engineered, conditionally replicating herpes simplex virus (HSV) that has shown tumor-specific tropism and potential efficacy in the treatment of malignant brain tumors. G207 is a genetically engineered HSV-1 lacking genes essential for replication in normal brain cells. Safety has been established in preclinical investigations involving intracranial inoculation in the highly HSV-sensitive owl monkey (Aotus nancymai), and in three adult phase 1 trials in recurrent/progressive high-grade gliomas. No dose-limiting toxicities were seen in the adult studies and a maximum tolerated dose was not reached. Approximately half of the 35 treated adults had radiographic or neuropathologic evidence of response at a minimum of one time point. Preclinical studies in pediatric brain tumor models indicate that a variety of pediatric tumor types are highly sensitive to killing by G207. This clinical protocol outlines a first in human children study of intratumoral inoculation of an oncolytic virus via catheters placed directly into recurrent or progressive supratentorial malignant tumors.
- Published
- 2017
- Full Text
- View/download PDF
44. Molecular association of glucose-6-phosphate isomerase and pyruvate kinase M2 with glyceraldehyde-3-phosphate dehydrogenase in cancer cells.
- Author
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Das MR, Bag AK, Saha S, Ghosh A, Dey SK, Das P, Mandal C, Ray S, Chakrabarti S, Ray M, and Jana SS
- Subjects
- Animals, Carcinoma, Ehrlich Tumor metabolism, Disease Models, Animal, Enzyme Activation drug effects, Gene Expression, Glucose-6-Phosphate Isomerase chemistry, Glucose-6-Phosphate Isomerase genetics, Glyceraldehyde-3-Phosphate Dehydrogenases chemistry, Glyceraldehyde-3-Phosphate Dehydrogenases genetics, Mass Spectrometry, Mice, Neoplasms genetics, Protein Binding, Protein Interaction Domains and Motifs, Pyruvaldehyde pharmacology, Pyruvate Kinase chemistry, Pyruvate Kinase genetics, Glucose-6-Phosphate Isomerase metabolism, Glyceraldehyde-3-Phosphate Dehydrogenases metabolism, Neoplasms metabolism, Pyruvate Kinase metabolism
- Abstract
Background: For a long time cancer cells are known for increased uptake of glucose and its metabolization through glycolysis. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key regulatory enzyme of this pathway and can produce ATP through oxidative level of phosphorylation. Previously, we reported that GAPDH purified from a variety of malignant tissues, but not from normal tissues, was strongly inactivated by a normal metabolite, methylglyoxal (MG). Molecular mechanism behind MG mediated GAPDH inhibition in cancer cells is not well understood., Methods: GAPDH was purified from Ehrlich ascites carcinoma (EAC) cells based on its enzymatic activity. GAPDH associated proteins in EAC cells and 3-methylcholanthrene (3MC) induced mouse tumor tissue were detected by mass spectrometry analysis and immunoprecipitation (IP) experiment, respectively. Interacting domains of GAPDH and its associated proteins were assessed by in silico molecular docking analysis. Mechanism of MG mediated GAPDH inactivation in cancer cells was evaluated by measuring enzyme activity, Circular dichroism (CD) spectroscopy, IP and mass spectrometry analyses., Result: Here, we report that GAPDH is associated with glucose-6-phosphate isomerase (GPI) and pyruvate kinase M2 (PKM2) in Ehrlich ascites carcinoma (EAC) cells and also in 3-methylcholanthrene (3MC) induced mouse tumor tissue. Molecular docking analyses suggest C-terminal domain preference for the interaction between GAPDH and GPI. However, both C and N termini of PKM2 might be interacting with the C terminal domain of GAPDH. Expression of both PKM2 and GPI is increased in 3MC induced tumor compared with the normal tissue. In presence of 1 mM MG, association of GAPDH with PKM2 or GPI is not perturbed, but the enzymatic activity of GAPDH is reduced to 26.8 ± 5 % in 3MC induced tumor and 57.8 ± 2.3 % in EAC cells. Treatment of MG to purified GAPDH complex leads to glycation at R399 residue of PKM2 only, and changes the secondary structure of the protein complex., Conclusion: PKM2 may regulate the enzymatic activity of GAPDH. Increased enzymatic activity of GAPDH in tumor cells may be attributed to its association with PKM2 and GPI. Association of GAPDH with PKM2 and GPI could be a signature for cancer cells. Glycation at R399 of PKM2 and changes in the secondary structure of GAPDH complex could be one of the mechanisms by which GAPDH activity is inhibited in tumor cells by MG.
- Published
- 2016
- Full Text
- View/download PDF
45. All You Need to Know as an Authorized User.
- Author
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Baldwin JA, Bag AK, White SL, Palot-Manzil FF, and O'Malley JP
- Subjects
- Government Regulation, Humans, Medical Waste Disposal standards, Nuclear Medicine education, Radiation Dosage, Radiation Protection standards, Radioactive Hazard Release prevention & control, Radioactive Waste, Radiology education, Radiopharmaceuticals, Specialty Boards, United States, Licensure, Nuclear Medicine standards, Practice Management, Medical standards, Radiology standards
- Abstract
Objective: The purpose of this article is to review the training requirements for practicing nuclear radiology, the scope of licensing, how to start a new practice, and the key concepts an authorized user needs to know for responsible use of radiopharmaceuticals., Conclusion: Physicians responsible for the daily operations of nuclear medicine clinics often find the regulations concerning the safe handling and administration of radiopharmaceuticals daunting. Even experienced authorized users have concerns about handling many new therapeutic agents. Those studying for certifying and subspecialty examinations or for maintenance of certification for the American Board of Nuclear Medicine and the American Board of Radiology must clearly understand the overall process for becoming an authorized user.
- Published
- 2015
- Full Text
- View/download PDF
46. Neurodegeneration with Brain Iron Accumulation: Clinicoradiological Approach to Diagnosis.
- Author
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Amaral LL, Gaddikeri S, Chapman PR, Roy R, Gaddikeri RS, Marussi VH, and Bag AK
- Subjects
- Brain pathology, Humans, Image Enhancement methods, Genetic Predisposition to Disease genetics, Iron Overload diagnosis, Iron Overload genetics, Magnetic Resonance Imaging methods, Neurodegenerative Diseases diagnosis, Neurodegenerative Diseases genetics
- Abstract
Discovery of genetic abnormalities associated with neurodegeneration with brain iron accumulation (NBIA) has led to use of a genetic-based NBIA classification schema. Most NBIA subtypes demonstrate characteristic imaging abnormalities. While clinical diagnosis of NBIA is difficult, analysis of both clinical findings and characteristic imaging abnormalities allows accurate diagnosis of most of the NBIA subtypes. This article reviews recent updates in the genetic, clinical, and imaging findings of NBIA subtypes and provides a practical step-by-step clinicoradiological algorithm toward clinical diagnosis of different NBIA subtypes., (Copyright © 2014 by the American Society of Neuroimaging.)
- Published
- 2015
- Full Text
- View/download PDF
47. Prolonged treatment with bevacizumab is associated with brain atrophy: a pilot study in patients with high-grade gliomas.
- Author
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Bag AK, Kim H, Gao Y, Bolding M, Warren PP, Fathallah-Shaykh HM, Gurler D, Markert JM, Fiveash J, Beasley TM, Khawaja A, Friedman GK, Chapman PR, Nabors LB, and Han X
- Subjects
- Adult, Aged, Analysis of Variance, Atrophy chemically induced, Atrophy pathology, Brain Neoplasms drug therapy, Female, Follow-Up Studies, Functional Laterality, Glioma drug therapy, Humans, Imaging, Three-Dimensional, Magnetic Resonance Imaging, Male, Middle Aged, Pilot Projects, Retrospective Studies, Angiogenesis Inhibitors adverse effects, Bevacizumab adverse effects, Brain drug effects, Brain pathology
- Abstract
Bevacizumab is widely used for treatment of high-grade gliomas and other malignancies. Because bevacizumab has been shown to be associated with neurocognitive decline, this study is designed to investigate whether prolonged treatment with bevacizumab is also associated with brain atrophy. We identified 12 high-grade glioma patients who received bevacizumab for 12 months at the first recurrence and 13 matched controls and blindly compared the volumes of the contralateral hemispheres and contralateral ventricle in these two groups at baseline and after 12 ± 2 months of the baseline scan by two independent analyses. The volumes of the contralateral hemispheres and ventricles did not differ significantly between the two groups at baseline. Whereas, in the control group the volumes of the contralateral hemisphere changed subtly from baseline to follow-up (p = 0.23), in the bevacizumab-treated group the volumes significantly decreased from baseline to follow-up (p = 0.03). There was significant increase in the contralateral ventricle volume from base line to follow-up scans in both the control group (p = 0.01) and in the bevacizumab group (p = 0.005). Both the absolute and the percentage changes of contralateral hemisphere volumes and contralateral ventricular volumes between the two patient groups were statistically significant (p < 0.05). Results of this study demonstrate prolonged treatment with bevacizumab is associated with atrophy of the contralateral brain hemisphere.
- Published
- 2015
- Full Text
- View/download PDF
48. Practical imaging of the parotid gland.
- Author
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Bag AK, Curé JK, Chapman PR, Pettibon KD, and Gaddamanugu S
- Subjects
- Angiography, Digital Subtraction, Diagnostic Imaging, Humans, Magnetic Resonance Imaging, Parotid Gland diagnostic imaging, Parotid Gland pathology, Tomography, X-Ray Computed, Parotid Diseases diagnosis, Positron-Emission Tomography methods
- Abstract
The parotid gland may be affected by numerous pathologies, and physicians from many different medical and surgical specialties request parotid imaging. Mastering the typical imaging features of various types of parotid pathology is facilitated by understanding how various diseases produce their characteristic imaging findings. In this review article, we present succinct overviews of the normal anatomy and the common pathologies of the parotid gland and recommend a practical approach to differential diagnosis that can be easily implemented in day-to-day radiology practice.
- Published
- 2015
- Full Text
- View/download PDF
49. Are there differences between macrocyclic gadolinium contrast agents for brain tumor imaging? Results of a multicenter intraindividual crossover comparison of gadobutrol with gadoteridol (the TRUTH study).
- Author
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Maravilla KR, Smith MP, Vymazal J, Goyal M, Herman M, Baima JJ, Babbel R, Vaneckova M, Žižka J, Colosimo C, Urbańczyk-Zawadzka M, Mechl M, Bag AK, Bastianello S, Bueltmann E, Hirai T, Frattini T, Kirchin MA, and Pirovano G
- Subjects
- Adult, Aged, Cross-Over Studies, Female, Gadolinium administration & dosage, Humans, Male, Middle Aged, Neuroimaging methods, Brain Neoplasms diagnosis, Contrast Media administration & dosage, Heterocyclic Compounds administration & dosage, Magnetic Resonance Imaging methods, Organometallic Compounds administration & dosage
- Abstract
Background and Purpose: Gadobutrol (Gadavist) and gadoteridol (ProHance) have similar macrocyclic molecular structures, but gadobutrol is formulated at a 2-fold higher (1 mol/L versus 0.5 mol/L) concentration. We sought to determine whether this difference impacts morphologic contrast-enhanced MR imaging., Materials and Methods: Two hundred twenty-nine adult patients with suspected or known brain tumors underwent two 1.5T MR imaging examinations with gadoteridol or gadobutrol administered in randomized order at a dose of 0.1 mmol/kg of body weight. Imaging sequences and T1 postinjection timing were identical for both examinations. Three blinded readers evaluated images qualitatively and quantitatively for lesion detection and for accuracy in characterization of histologically confirmed brain tumors. Data were analyzed by using the Wilcoxon signed rank test, the McNemar test, and a mixed model., Results: Two hundred nine patients successfully completed both examinations. No reader noted a significant qualitative or quantitative difference in lesion enhancement, extent, delineation, or internal morphology (P values = .69-1.00). One hundred thirty-nine patients had at least 1 histologically confirmed brain lesion. Two readers found no difference in the detection of patients with lesions (133/139 versus 135/139, P = .317; 137/139 versus 136/139, P = .564), while 1 reader found minimal differences in favor of gadoteridol (136/139 versus 132/139, P = .046). Similar findings were noted for the number of lesions detected and characterization of tumors (malignant/benign). Three-reader agreement for characterization was similar for gadobutrol (66.4% [κ = 0.43]) versus gadoteridol (70.3% [κ = 0.45]). There were no significant differences in the incidence of adverse events (P = .199)., Conclusions: Gadoteridol and gadobutrol at 0.1 mmol/kg of body weight provide similar information for visualization and diagnosis of brain lesions. The 2-fold higher gadolinium concentration of gadobutrol provides no benefit for routine morphologic imaging., (© 2015 by American Journal of Neuroradiology.)
- Published
- 2015
- Full Text
- View/download PDF
50. Case 212: chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids.
- Author
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Bag AK, Davenport JJ, Hackney JR, Roy R, and Fathallah-Shaykh HM
- Subjects
- Biopsy, Brain Diseases pathology, Chronic Disease, Diagnosis, Differential, Flow Cytometry, Humans, Immunohistochemistry, Brain Diseases diagnosis, Brain Diseases drug therapy, Brain Stem pathology, Cerebellum pathology, Diffusion Magnetic Resonance Imaging, Glucocorticoids therapeutic use, Pons pathology
- Abstract
History A previously healthy 23-year-old white man presented to the emergency department of our hospital with a 2-month history of dysarthria, progressively worsening vertigo, and difficulty walking. A diagnosis of retinitis pigementosa was made in this patient's childhood. He did not have any history of congenital syphilis. He did not have a history of nausea or vomiting, fever, weight loss, headache, photophobia, seizure, extremity weakness, or sensory disturbance. Physical examination revealed dysarthria, dysmetria, and ataxia. Kernig and Brudzinski signs were absent, and pathergy test results were negative. Laboratory evaluation revealed normal complete and differential blood counts and normal serum chemistry, including a normal serum angiotensin-converting enzyme level. Analysis of his serum was negative for antinuclear antibody (or ANA), cytoplasmic antineutrophil cvtoplasmic antibody (or cANCA), Sjögren syndrome antigens A and B (SS-A and SS-B, respectively), antitissue transglutaminase and antiendomysial antibodies, and paraneoplastic profile. Serum analysis was also negative for human immunodeficiency virus type 1 and type 2 RNA, Venereal Disease Research Laboratory (VDRL) test, rapid plasma regain (RPR), and fluorescent treponemal antibody absorption. Cerebrospinal fluid (CSF) analysis revealed clear fluid, a normal glucose level (64 mg/dL [3.6 mmol/L]; normal range, 40-70 mg/dL [2.2-3.9 mmol/L]), an elevated protein level (97 mg/dL; normal range, 12-60 mg/dL), and an elevated white blood cell count (7/mm(3) [0.007 ×10(9)/L] in tube 1 and 17/mm(3) [0.017 × 10(9)/L] in tube 2) with 84% lymphocytes. CSF immunoglobulin G level was elevated (30.1 mg/dL; normal, <5.9 mg/dL); however, there were no oligoclonal bands. Gram staining, acid-fast staining, and lactic acid, cryptococcal antigen, histoplasma antigen, herpes simplex virus polymerase chain reaction, VDRL, and RPR test results for CSF were negative. CSF did not grow any bacteria, fungus, or acid-fast bacillus at culture. CSF flow cytometry did not reveal a monoclonal lymphoid population. Initial imaging included brain magnetic resonance (MR) imaging. Computed tomography (CT) images of the chest, abdomen, and pelvis were normal (not shown). The patient's clinical symptoms and imaging findings responded to treatment with a high dose of oral steroids. However, the patient's symptoms exhibited clinical and radiologic progression after several attempts to taper the steroid dose.
- Published
- 2014
- Full Text
- View/download PDF
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