16 results on '"Nathan F Clement"'
Search Results
2. Fatal neurotoxicity after chimeric antigen receptor T-cell therapy: An unexpected case of fludarabine-associated progressive leukoencephalopathy
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Nathan F. Clement, Jorg Dietrich, Ephraim P. Hochberg, Maria Martinez-Lage, and Sebastian F Winter
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Cancer Research ,Oncology ,Progressive leukoencephalopathy ,business.industry ,Cancer research ,Neurotoxicity ,Medicine ,Chimeric Antigen Receptor T-Cell Therapy ,business ,medicine.disease ,Fludarabine ,medicine.drug - Published
- 2021
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3. A Simplified Brain Blocking Protocol Optimized for the Diagnosis of Neurodegenerative Disease Saves Time and Money While Preserving Anatomic Relationships
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Wesley R Samore, E. Tessa Hedley-Whyte, Nathan F. Clement, Maria Martinez-Lage, John C. DeWitt, and Matthew P. Frosch
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Male ,0301 basic medicine ,medicine.medical_specialty ,Time Factors ,Cost-Benefit Analysis ,Efficiency ,Disease ,Article ,Specimen Handling ,Workflow ,Pathology and Forensic Medicine ,Progressive supranuclear palsy ,03 medical and health sciences ,0302 clinical medicine ,Cost Savings ,Predictive Value of Tests ,Lewy pathology ,medicine ,Humans ,Corticobasal degeneration ,Prospective Studies ,Medical diagnosis ,Aged ,Aged, 80 and over ,Histocytological Preparation Techniques ,business.industry ,Brain ,Reproducibility of Results ,Neurodegenerative Diseases ,General Medicine ,Middle Aged ,medicine.disease ,Medical Laboratory Technology ,030104 developmental biology ,Case-Control Studies ,Standard protocol ,Female ,Autopsy ,Cerebral amyloid angiopathy ,Radiology ,Alzheimer's disease ,business ,030217 neurology & neurosurgery - Abstract
Context.— Postmortem evaluation for neurodegenerative disease is expensive in time and materials. These challenges can be met by implementing simpler sampling protocols while preserving anatomic relations. Objective.— To determine the diagnostic effectiveness and cost-effectiveness of a simplified brain blocking protocol compared with the standard blocking protocol used in our Alzheimer's Disease Research Center (ADRC). Design.— We prospectively compared the neuropathologic diagnoses established from our standard 19-cassette/19 brain sites ADRC protocol to a simplified 6-cassette/12 brain sites protocol in 52 consecutive cases. The simplified protocol generated 14 slides for comparison to 52 slides from our standard protocol. Results.— Compared with the ADRC protocol the simplified protocol produced Alzheimer Disease Neuropathologic Changes probability scores that were the same in 50 of 52 cases (r = 0.99). Staging for Lewy pathology was equivalent in 45 of 52 (r = 0.98), scoring for cerebral amyloid angiopathy was equivalent in 48 of 52 (r = 0.97), and grading for arteriolosclerosis was the same in 45 of 52 cases (r = 0.92). Progressive supranuclear palsy (n = 4), multiple system atrophy (n = 2), and corticobasal degeneration (n = 1) could be diagnosed by either protocol independently. The estimated savings per case was 72% or $1744.89 ($2436.37 [ADRC] versus $691.48 [simplified]). Conclusions.— The diagnosis of neurodegenerative disease at autopsy can be done accurately with a less expensive, simplified protocol. Our protocol is similar to those of previously published approaches, but it has a simpler organization scheme. This method should be valuable to institutions where autopsy cost considerations may be important.
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- 2020
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4. Severe Neurological Toxicity of Immune Checkpoint Inhibitors: Growing Spectrum
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Meghan J. Mooradian, Donald F. Chute, William S. David, Ryan J. Sullivan, Donald P. Lawrence, Divyanshu Dubey, Nathan F. Clement, Kerry L. Reynolds, Amanda C. Guidon, and Justine V. Cohen
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0301 basic medicine ,medicine.medical_specialty ,Combination therapy ,business.industry ,Immune checkpoint inhibitors ,MEDLINE ,Tertiary care ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Neurology ,Toxicity ,medicine ,Neurology (clinical) ,Relapse risk ,Intensive care medicine ,business ,Adverse effect ,030217 neurology & neurosurgery - Abstract
Expanding use of immune-checkpoint inhibitors (ICIs) underscores the importance of accurate diagnosis and timely management of neurological immune-related adverse events (irAE-N). We evaluate the real-world frequency, phenotypes, co-occurring immune-related adverse events (irAEs), and long-term outcomes of severe, grade III to V irAE-N at a tertiary care center over 6 years. We analyze how our experience supports published literature and professional society guidelines. We also discuss these data with regard to common clinical scenarios, such as combination therapy, ICI rechallenge and risk of relapse of irAE-N, and corticosteroid taper, which are not specifically addressed by current guidelines and/or have limited data. Recommendations for management and future irAE-N reporting are outlined. ANN NEUROL 2020;87:659-669.
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- 2020
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5. Varied phenotypes and management of immune checkpoint inhibitor-associated neuropathies
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William S. David, Meghan J. Mooradian, Amanda C. Guidon, Justine V. Cohen, Anthony A. Amato, Divyanshu Dubey, Donald P. Lawrence, Ryan J. Sullivan, Kerry L. Reynolds, Nathan F. Clement, and Donald F. Chute
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Pain ,Gastroenterology ,Polyneuropathies ,03 medical and health sciences ,0302 clinical medicine ,Adrenal Cortex Hormones ,Modified Rankin Scale ,Internal medicine ,Humans ,Medicine ,Registries ,Adverse effect ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Mononeuritis Multiplex ,Disease Management ,Peripheral Nervous System Diseases ,Retrospective cohort study ,Immunosuppression ,Middle Aged ,medicine.disease ,Genes, cdc ,Phenotype ,030220 oncology & carcinogenesis ,Adenocarcinoma ,Female ,Neurology (clinical) ,business ,Complication ,Meningitis ,Immunosuppressive Agents ,030217 neurology & neurosurgery - Abstract
ObjectiveTo describe the spectrum, clinical course, and management of neuropathies associated with immune checkpoint inhibitors (ICIs).MethodsPatients with ICI-related neuropathy (irNeuropathy) were identified and their clinical characteristics compared to neuropathy attributed to cytotoxic agents.ResultsWe identified 19 patients with irNeuropathies. ICIs included anti-programmed death–1 (PD1), 9; anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA4), 2; and combination of anti-CTLA4 and anti-PD1, 8. Median number of ICI doses prior to neuropathy onset was 4. Rate of neuropathies following ICI therapy was 0.7%. Underlying malignancies included melanoma (n = 15), lung adenocarcinoma (n = 3), and cholangiocarcinoma (n = 1). Neuropathy phenotypes were cranial neuropathies with or without meningitis (n = 7), nonlength-dependent polyradiculoneuropathies with and without cranial nerve involvement (n = 6), small-fiber/autonomic neuropathy (n = 2), ANCA-associated mononeuritis multiplex (n = 1), sensory neuronopathy (n = 1), length-dependent sensorimotor axonal polyneuropathy (n = 1), and neuralgic amyotrophy (n = 1). Immune-related adverse events involving other organ systems were common (58%). Corticosteroid use for management of neuropathy was associated with improvement in median modified Rankin Scale score (1 vs 0, p = 0.001) and Inflammatory Neuropathy Cause and Treatment Disability score (2 vs 0.5, p = 0.012) (Class IV). Significantly higher proportion of irNeuropathies had acute or subacute and nonlength-dependent presentations (p < 0.001) and rate of hospitalization for irNeuropathy was also higher (p = 0.002) compared to toxic neuropathy from chemotherapy.ConclusionNeuropathy is a rare complication of ICIs that often responds to immunosuppression. Recognition of its wide phenotypic spectrum and distinct clinical characteristics and prompt management with corticosteroids may lead to favorable outcomes.
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- 2019
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6. Neuropathologic correlates of amyloid and dopamine transporter imaging in Lewy body disease
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Aaron P. Schultz, Stephen N. Gomperts, Nathan F. Clement, Rong Ye, Samantha Katz, Matthew P. Frosch, Julia Shirvan, John H. Growdon, Keith A. Johnson, and Teresa Gomez-Isla
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Lewy Body Disease ,Male ,0301 basic medicine ,Pathology ,medicine.medical_specialty ,Amyloid ,Contrast Media ,Standardized uptake value ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Cocaine ,mental disorders ,Humans ,Medicine ,Senile plaques ,Aged ,Aged, 80 and over ,Dopamine Plasma Membrane Transport Proteins ,Amyloid beta-Peptides ,Aniline Compounds ,Lewy body ,business.industry ,Dementia with Lewy bodies ,Brain ,Parkinson Disease ,Neurofibrillary tangle ,Middle Aged ,medicine.disease ,Thiazoles ,030104 developmental biology ,chemistry ,Positron-Emission Tomography ,Female ,Autopsy ,Neurology (clinical) ,Cerebral amyloid angiopathy ,Pittsburgh compound B ,business ,030217 neurology & neurosurgery - Abstract
ObjectiveTo develop imaging biomarkers of diseases in the Lewy body spectrum and to validate these markers against postmortem neuropathologic findings.MethodsFour cognitively normal participants with Parkinson disease (PD), 4 with PD with cognitive impairments, and 10 with dementia with Lewy bodies underwent amyloid imaging with [11C]Pittsburgh compound B (PiB) and dopamine transporter (DAT) imaging with [11C]Altropane. All 18 had annual neurologic examinations. All cognitively normal participants with PD developed cognitive impairment before death. Neuropathologic examinations assessed and scored Braak Lewy bodies, Thal distribution of amyloid, Consortium to Establish a Registry for Alzheimer's Disease neuritic amyloid plaques, Braak neurofibrillary tangles, and cerebral amyloid angiopathy, as well as total amyloid plaque burden in the superior frontal, superior parietal, occipital, and inferior temporal cortical regions. PET data were expressed as the standardized uptake value ratio with cerebellar reference. Analyses accounted for the interval between imaging and autopsy.ResultsAll 18 patients met neuropathologic criteria for Lewy body disease; the DAT concentration was low in each case. All patients with elevated [11C]PiB retention measured in a neocortical aggregate had β-amyloid deposits at autopsy. [11C]PiB retention significantly correlated with neuritic plaque burden and with total plaque burden. [11C]PiB retention also significantly correlated with the severity of both Braak stages of neurofibrillary tangle and Lewy body scores. Neuritic plaque burden was significantly associated with neurofibrillary tangle pathology.ConclusionAntemortem [11C]Altropane PET is a sensitive measure of substantia nigra degeneration. [11C]PiB scans accurately reflect cortical amyloid deposits seen at autopsy. These findings support the use of molecular imaging in the evaluation of patients with Lewy body diseases.
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- 2019
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7. Intradural extramedullary pleomorphic xanthoastrocytoma: A case report
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Rebecca L Dillon, Nathan F Clement, Francis J Cloran, Daniel R Klinger, and Iren Horkayne-Szakaly
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medicine.medical_specialty ,Central nervous system ,Case Report ,law.invention ,Intramedullary rod ,Lesion ,03 medical and health sciences ,0302 clinical medicine ,law ,medicine ,Pleomorphic xanthoastrocytoma ,Neck pain ,business.industry ,Case description ,medicine.disease ,medicine.anatomical_structure ,Spinal cord tumor ,030220 oncology & carcinogenesis ,Surgery ,Neurology (clinical) ,Radiology ,medicine.symptom ,business ,Intradural extramedullary ,030217 neurology & neurosurgery ,Primary - Abstract
Background: Pleomorphic xanthoastrocytomas (PXAs) are uncommon intradural and typically intramedullary astrocytic central nervous system tumors. Although they commonly occur supratentorially, they are rarely seen in the spine. Case Description: A 43-year-old male presented with cervical neck pain and right-sided radicular symptoms. He was found to have an intradural extramedullary mass at the C5–C6 level. The lesion was fully excised and proved to be a PXA. Of interest, the lesion did not recur on postoperative MR imaging studies obtained 7 months later. Conclusion: While rare, primary intradural extramedullary spinal PXA has been reported. Here, we review such a lesion occurring in a 43-year-old male who did well following gross total excision of the tumor.
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- 2020
8. Comparison of direct site endovascular repair utilizing expandable polytetrafluoroethylene stent grafts versus standard vascular shunts in a porcine (Sus scrofa) model
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Timothy K. Williams, Nathan F. Clement, Lucas P. Neff, Christopher M. Abbot, J. Kevin Grayson, James B. Sampson, Anders J. Davidson, Erik S. DeSoucy, and Meryl A. Simon Logan
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medicine.medical_specialty ,Swine ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Anastomosis ,Prosthesis Design ,Critical Care and Intensive Care Medicine ,Iliac Artery ,Blood Vessel Prosthesis Implantation ,03 medical and health sciences ,0302 clinical medicine ,Blood vessel prosthesis ,medicine ,Animals ,Vascular Patency ,Polytetrafluoroethylene ,medicine.diagnostic_test ,business.industry ,Endovascular Procedures ,Angiography ,Stent ,030208 emergency & critical care medicine ,Blood flow ,Vascular System Injuries ,medicine.disease ,Thrombosis ,Blood Vessel Prosthesis ,Surgery ,Disease Models, Animal ,medicine.anatomical_structure ,Stents ,business ,Blood Flow Velocity ,Artery - Abstract
Introduction The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expandable polytetrafluoroethylene stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared with standard shunts in a survival model of porcine vascular injury. Methods Twelve Yorkshire-cross swine received a 2-cm-long near-circumferential defect in the bilateral iliac arteries. A 14 Fr Argyle shunt was inserted into one randomly assigned artery, with a self-expanding expandable polytetrafluoroethylene stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. Results Angiography revealed no difference in patency at 72 hours (p = 1.0). While there was no difference in baseline arterial flow between arteries (p = 0.63), the stent grafts demonstrated significantly improved blood flow compared with shunts both immediately after intervention (390 ± 36 mL/min vs. 265 ± 25 mL/min, p = 0.002) and at 72 hours (261 ± 29 mL/min vs. 170 ± 36 mL/min, p = 0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5 mm Hg [interquartile range, 3-19 mm Hg] vs. 3 mm Hg [interquartile range, 3-5 mm Hg], p = 0.013). The speed of deployment was similar between the two devices. Conclusions Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared with temporary shunts. Furthermore, stent grafts may offer improved durability to extend the window until definitive vascular repair. The combination of these traits may improve outcomes after vascular injury. Level of evidence Epidemiologic/Prognostic, level III.
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- 2017
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9. Case 22-2019: A 65-Year-Old Woman with Weakness, Dark Urine, and Dysphagia
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Mason W. Freeman, Amanda C. Guidon, Ajay K. Singh, Nathan F. Clement, Sheila L. Arvikar, and Robert H. Goldstein
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medicine.medical_specialty ,Weakness ,genetic structures ,Carotid arteries ,Difficulty swallowing ,030204 cardiovascular system & hematology ,Rhabdomyolysis ,Autoimmune Diseases ,Diagnosis, Differential ,03 medical and health sciences ,0302 clinical medicine ,Skeletal pathology ,X ray computed ,otorhinolaryngologic diseases ,medicine ,Atorvastatin ,Humans ,Medical history ,030212 general & internal medicine ,Muscle, Skeletal ,Aged ,Muscle Weakness ,Myositis ,business.industry ,General surgery ,Myoglobinuria ,General Medicine ,Cerebral Infarction ,Dysphagia ,Dark urine ,Female ,sense organs ,medicine.symptom ,Hydroxymethylglutaryl-CoA Reductase Inhibitors ,business ,Deglutition Disorders ,Tomography, X-Ray Computed ,Carotid Artery, Internal ,Magnetic Resonance Angiography - Abstract
A Woman with Weakness, Dark Urine, and Dysphagia A 65-year-old woman was admitted to this hospital because of falls, weakness, dark urine, and difficulty swallowing. Her medical history was notable...
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- 2019
10. Extending the golden hour
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Lucas P. Neff, John Kevin Grayson, Rachel M. Russo, Timothy K. Williams, Nathan F. Clement, Jeremy W. Cannon, Christopher M. Lamb, and Joseph M. Galante
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medicine.medical_specialty ,Mean arterial pressure ,Swine ,Resuscitation ,Hemodynamics ,Aorta, Thoracic ,Abdominal Injuries ,Critical Care and Intensive Care Medicine ,Balloon ,03 medical and health sciences ,0302 clinical medicine ,Exsanguination ,medicine.artery ,Internal medicine ,Occlusion ,medicine ,Animals ,Thoracic aorta ,030212 general & internal medicine ,Aorta ,business.industry ,Endovascular Procedures ,030208 emergency & critical care medicine ,Blood flow ,Balloon Occlusion ,Disease Models, Animal ,Liver ,Cardiology ,Surgery ,business ,Perfusion - Abstract
BACKGROUND Combat-injured patients may require rapid and sustained support during transport; however, the prolonged aortic occlusion produced by conventional resuscitative endovascular balloon occlusion of the aorta (REBOA) may lead to substantial morbidity. Partial REBOA (P-REBOA) may permit longer periods of occlusion by allowing some degree of distal perfusion. However, the ability of this procedure to limit exsanguination is unclear. We evaluated the impact of P-REBOA on immediate survival and ongoing hemorrhage in a highly lethal swine liver injury model. METHODS Fifteen Yorkshire-cross swine were anesthetized, instrumented, splenectomized, and subjected to rapid 10% total blood loss followed by 30% liver amputation. Coagulopathy was created through colloid hemodilution. Randomized swine received no intervention (control), P-REBOA, or complete REBOA (C-REBOA). Central mean arterial pressure (cMAP), carotid blood flow, and blood loss were recorded. Balloons remained inflated in the P-REBOA and C-REBOA groups for 90 minutes followed by graded deflation. The study ended at 180 minutes from onset of hemorrhage or death of the animal. Survival analysis was performed, and data were analyzed using repeated-measures analysis of variance with post hoc pairwise comparisons. RESULTS Mean survival times in the control, P-REBOA, and C-REBOA groups were, 25 ± 21, 86 ± 40, and 163 ± 20 minutes, respectively (p < 0.001). Blood loss was greater in the P-REBOA group than the C-REBOA or control groups, but this difference was not significant (4,722 ± 224, 3,834 ± 319, 3,818 ± 37 mL, respectively, p = 0.10). P-REBOA resulted in maintenance of near-baseline carotid blood flow and cMAP, while C-REBOA generated extreme cMAP and prolonged supraphysiologic carotid blood flow. Both experimental groups experienced profound decreases in cMAP following balloon deflation. CONCLUSION In the setting of severe ongoing hemorrhage, P-REBOA increased survival time beyond the golden hour while maintaining cMAP and carotid flow at physiologic levels.
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- 2016
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11. Clinical presentation, management, and biomarkers of neurotoxicity after adoptive immunotherapy with CAR T cells
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Michaela H. Schwaiblmair, Jeremy S. Abramson, Jacob D. Soumerai, L. Nicolas Gonzalez Castro, Philipp Karschnia, Ephraim P. Hochberg, Marcela V. Maus, Ronald W. Takvorian, Nathan F. Clement, Justin T. Jordan, Matthew J. Frigault, Joachim M. Baehring, Aline Herlopian, Isabel Arrillaga-Romany, Jorg Dietrich, Jeffrey A. Barnes, Deborah Forst, and Tracy T. Batchelor
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0301 basic medicine ,Adult ,Male ,Neurotoxicity Syndrome ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,medicine.medical_treatment ,Immunology ,Biochemistry ,Gastroenterology ,Immunotherapy, Adoptive ,Cohort Studies ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Internal medicine ,medicine ,Carcinoma ,Humans ,Adverse effect ,Aged ,business.industry ,Lymphoma, Non-Hodgkin ,Liver Neoplasms ,Neurotoxicity ,Disease Management ,Cell Biology ,Hematology ,Immunotherapy ,Middle Aged ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,medicine.disease ,Lymphoma ,Cytokine release syndrome ,030104 developmental biology ,Treatment Outcome ,030220 oncology & carcinogenesis ,Chimeric Antigen Receptor T-Cell Therapy ,Female ,Neurotoxicity Syndromes ,business ,Biomarkers - Abstract
Chimeric antigen receptor (CAR) T cells have emerged as a promising class of cell-based immunotherapy in refractory malignancies. Neurotoxicity represents a common and potentially life-threatening adverse effect of CAR T cells, and clinical experience is limited. Here, we describe the clinical presentation and management of 25 adult patients who presented with neurotoxic syndromes after CAR T-cell therapy at the Massachusetts General Hospital. This cohort includes 24 patients treated with CD19-directed CAR T cells for non-Hodgkin lymphoma (n = 23) and acute lymphoblastic leukemia (n = 1), and 1 patient treated with α-fetoprotein–directed CAR T cells for hepatocellular carcinoma (n = 1). Twelve of the 25 patients (48%) developed grade 1-2 neurotoxicity and 13 patients (52%) presented with grade 3-4 neurotoxicity. We found that lower platelet counts at time of CAR T-cell infusion were associated with more severe neurotoxicity (P = .030). Cytokine release syndrome occurred in 24 of 25 patients (96%). Serum levels of ferritin peaked with onset of neurologic symptoms, and higher ferritin levels were associated with higher neurotoxicity grade. Grade 3-4 neurotoxicity correlated negatively with overall survival (OS) (P = .013). Median OS of the entire cohort was 54.7 weeks. Eight patients (32%) with grade 3-4 neurotoxicity were deceased at database closure, whereas none died with neurotoxicity grade 1-2. High pretreatment lactate dehydrogenase was frequently encountered in lymphoma patients with grade 3-4 neurotoxicity and correlated negatively with progression-free survival (P = .048). We did not find evidence that steroid use ≥7 days altered the patient’s outcome when compared with
- Published
- 2018
12. Automated variable aortic control versus complete aortic occlusion in a swine model of hemorrhage
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Timothy K. Williams, Michael Austin Johnson, Anders J. Davidson, Lucas P. Neff, Todd E. Rasmussen, Rachel M. Russo, John Kevin Grayson, Nathan F. Clement, and Sarah-Ashley E. Ferencz
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medicine.medical_specialty ,Mean arterial pressure ,Resuscitation ,Swine ,Ischemia ,Hemodynamics ,Hemorrhage ,030204 cardiovascular system & hematology ,Critical Care and Intensive Care Medicine ,Article ,03 medical and health sciences ,Random Allocation ,0302 clinical medicine ,Internal medicine ,medicine.artery ,Medicine ,Animals ,Aorta ,Monitoring, Physiologic ,business.industry ,Hemostatic Techniques ,030208 emergency & critical care medicine ,medicine.disease ,Survival Rate ,Disease Models, Animal ,Liver ,Damage control surgery ,Renal blood flow ,Cardiology ,Surgery ,business ,Perfusion - Abstract
BACKGROUND Future endovascular hemorrhage control devices will require features that mitigate the adverse effects of vessel occlusion. Permissive regional hypoperfusion (PRH) with variable aortic control (VAC) is a novel strategy to minimize hemorrhage and reduce the ischemic burden of complete aortic occlusion (AO). The objective of this study was to compare PRH with VAC to AO in a lethal model of hemorrhage. METHODS Twenty-five swine underwent cannulation of the supraceliac aorta, with diversion of aortic flow through an automated extracorporeal circuit. After creation of uncontrolled liver hemorrhage, animals were randomized to 90 minutes of treatment: Control (full, unregulated flow; n = 5), AO (no flow; n = 10), and PRH with VAC (dynamic distal flow initiated after 20 minutes of AO; n = 10). In the PRH group, distal flow rates were regulated between 100 and 300 mL/min based on a desired, preset range of proximal mean arterial pressure (MAP). At 90 minutes, damage control surgery, resuscitation, and restoration of full flow ensued. Critical care continued for 4.5 hours or until death. Hemodynamic parameters and markers of ischemia were recorded. RESULTS Study survival was 0%, 50%, and 90% for control, AO, and VAC, respectively (p < 0.01). During intervention, VAC resulted in more physiologic proximal MAP (84 ± 18 mm Hg vs. 105 ± 9 mm Hg, p < 0.01) and higher renal blood flow than AO animals (p = 0.02). During critical care, VAC resulted in higher proximal MAP (73 ± 8 mm Hg vs. 50 ± 6 mm Hg, p < 0.01), carotid and renal blood flow (p < 0.01), lactate clearance (p < 0.01), and urine output (p < 0.01) than AO despite requiring half the volume of crystalloids to maintain proximal MAP ≥50 mm Hg (p < 0.01). CONCLUSION Permissive regional hypoperfusion with variable aortic control minimizes the adverse effects of distal ischemia, optimizes proximal pressure to the brain and heart, and prevents exsanguination in this model of lethal hemorrhage. These findings provide foundational knowledge for the continued development of this novel paradigm and inform next-generation endovascular designs.
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- 2017
13. Partial Resuscitative Endovascular Balloon Occlusion of the Aorta in Swine Model of Hemorrhagic Shock
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Timothy K. Williams, J. Kevin Grayson, Joseph M. Galante, Lucas P. Neff, Nathan F. Clement, Jeremy W. Cannon, Rachel M. Russo, and Christopher M. Lamb
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Male ,Mean arterial pressure ,medicine.medical_specialty ,Resuscitation ,Sus scrofa ,Ischemia ,Hemodynamics ,Blood volume ,030204 cardiovascular system & hematology ,Shock, Hemorrhagic ,Balloon ,03 medical and health sciences ,Random Allocation ,0302 clinical medicine ,Internal medicine ,medicine.artery ,medicine ,Animals ,Aorta ,business.industry ,Endovascular Procedures ,Balloon catheter ,030208 emergency & critical care medicine ,Balloon Occlusion ,medicine.disease ,Treatment Outcome ,Shock (circulatory) ,Anesthesia ,Cardiology ,Surgery ,Female ,medicine.symptom ,business - Abstract
BackgroundComplete resuscitative endovascular balloon occlusion of the aorta (C-REBOA) increases proximal mean arterial pressure (MAP) at the cost of distal organ ischemia, limiting the duration of intervention. We hypothesized that partial aortic occlusion (P-REBOA) would maintain a more physiologic proximal MAP and reduce distal tissue ischemia. We investigated the hemodynamic and physiologic effects of P-REBOA vs C-REBOA.Study DesignFifteen swine were anesthetized, instrumented, splenectomized, and subjected to rapid 25% blood volume loss. They were randomized to C-REBOA, P-REBOA, or no intervention (controls). Partial REBOA was created by partially inflating an aortic balloon catheter to generate a 50% blood pressure gradient across the balloon. Hemodynamics were recorded and serum makers of ischemia and inflammation were measured. After 90 minutes of treatment, balloons were deflated to evaluate the immediate effects of reperfusion. End organs were histologically examined.ResultsComplete REBOA produced supraphysiologic increases in proximal MAP after hemorrhage compared with more modest augmentation in the P-REBOA group (p < 0.01), with both groups significantly greater than controls (p < 0.01). Less rebound hypotension after balloon deflation was seen in the P-REBOA compared with C-REBOA groups. Complete REBOA resulted in higher serum lactate than both P-REBOA and controls (p < 0.01). Histology revealed early necrosis and disruption of duodenal mucosa in all C-REBOA animals, but none in P-REBOA animals.ConclusionsIn a porcine hemorrhagic shock model, P-REBOA resulted in more physiologically tolerable hemodynamic and ischemic changes compared with C-REBOA. Additional work is needed to determine whether the benefits associated with P-REBOA can both extend the duration of intervention and increase survival.
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- 2016
14. Effect of Light on Vitamin B12 and Folate
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Brian S. Kendall and Nathan F. Clement
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medicine.medical_specialty ,business.industry ,Biochemistry (medical) ,Clinical Biochemistry ,medicine ,Physiology ,Vitamin B12 ,business ,Surgery - Abstract
Background: Laboratory specimens submitted for assessment of vitamin B12 and folate have traditionally been light-protected, although this practice is based on limited data. Methods: This study compared changes in assayed values for B12 and folate from 25 healthy human volunteers when measured at 1, 2, and 7 days with both light-protection and light-exposure. Results: For B12, there was an average decrease of 7.5% at 7 days when lightprotected and a 7.7% decrease when lightexposed, while folate showed a 1.7% average decrease when light-exposed and a 1.0% decrease when light-protected. Neither of these values differed significantly between lightexposed or light-protected. Conclusions: This study demonstrates there is no need to light-protect specimens prior to vitamin B12 and folate analysis.
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- 2009
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15. High and intermediate grade ductal carcinoma in-situ of the breast: a comparison of pathologic features in core biopsies and excisions and an evaluation of core biopsy features that may predict a close or positive margin in the excision
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Oluwole Fadare, Nathan F. Clement, and Mohiedean Ghofrani
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In situ ,Pathology ,medicine.medical_specialty ,Histology ,medicine.diagnostic_test ,business.industry ,Research ,Sentinel lymph node ,General Medicine ,Ductal carcinoma ,medicine.disease ,Pathology and Forensic Medicine ,Immunophenotyping ,Biopsy ,Carcinoma ,medicine ,lcsh:Pathology ,Intermediate Grade ,business ,Core biopsy ,lcsh:RB1-214 - Abstract
Low and high-grade ductal carcinoma in-situ (DCIS) are known to be highly disparate by a multitude of parameters, including progression potential, immunophenotype, gene expression profile and DNA ploidy. In this study, we analyzed a group of intermediate and high-grade DCIS cases to determine how well the core biopsy predicts the maximal pathology in the associated excisions, and to determine if there are any core biopsy morphologic features that may predict a close (≤ 0.2 cm) or positive margin in the subsequent excision. Forty-nine consecutive paired specimens [core biopsies with a maximal diagnosis of DCIS, and their corresponding excisions, which included 20 and 29 specimens from mastectomies and breast conserving surgeries respectively] were evaluated in detail. In 5 (10%) of 49 cases, no residual carcinoma was found in the excision. In another 4 cases, the changes were diagnostic only of atypical ductal hyperplasia. There were 4 and 3 respective cases of invasive and microinvasive carcinoma out of the 49 excision specimens, for an overall invasion frequency of 14%. In 28 cases where a sentinel lymph node evaluation was performed, only 1 was found to be positive. Among the 40 cases with at least residual DCIS in the excision, there were 5 cases in which comedo-pattern DCIS was present in the excision but not in the core biopsy, attributed to the lower maximal nuclear grade in the biopsy proliferation in 4 cases and the absence of central necrosis in the 5th. For the other main histologic patterns, in 8 (20%) of 40 cases, there were more patterns identified in the core biopsy than in the corresponding excision. For the other 32 cases, 100%, 66%, 50%, 33% and 25% of the number of histologic patterns in the excisions were captured in 35%, 5%, 17.5%, 15% and 7.5% of the preceding core biopsies respectively. Therefore, the core biopsy reflected at least half of the non-comedo histologic patterns in 77.5% of cases. In 6(15%) of the 40 cases, the maximum nuclear grade of the excision (grade 3) was higher than that seen in the core biopsy (grade 2). Overall, however, the maximum nuclear grade in the excision was significantly predicted by maximum nuclear grade in the core biopsy (p = 0.028), with a Phi of 0.347, indicating a moderately strong association. At a size threshold of 2.7 cm, there was no significant association between lesional size and core biopsy features. Furthermore, the clear margin width of the cases with lesional size ≤ 2.7 cm (mean 0.69 cm) was not significantly different (p = 0.4) from the cases with lesional size > 2.7 cm (mean 0.56 cm). Finally, among a variety of core biopsy features that were evaluated, including maximum nuclear grade, necrosis, cancerization of lobules, number of tissue cores with DCIS, number of DCIS ducts per tissue core, total DCIS ducts, or comedo-pattern, only necrosis was significantly associated with a positive or close (≤ 0.2 cm) margin on multivariate analysis (Phi of 0.350). It is concluded that a significant change [to invasive disease (14%) or to no residual disease (10%)] is seen in approximately 24% of excisions that follow a core biopsy diagnosis of intermediate or high-grade DCIS. Core biopsy features are of limited value in predicting a close or positive margin in these lesions.
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- 2009
16. Effect of Light on Vitamin B12 and Folate.
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Nathan F. Clement
- Subjects
VITAMIN B12 ,VITAMIN B complex ,LIGHT ,LIGHT sources ,RESEARCH - Abstract
BACKGROUND: Laboratory specimens submitted for assessment of vitamin B12 and folate have traditionally been light-protected, although this practice is based on limited data. METHODS: This study compared changes in assayed values for B12 and folate from 25 healthy human volunteers when measured at 1, 2, and 7 days with both light-protection and light-exposure. RESULTS: For B12, there was an average decrease of 7.5% at 7 days when light-protected and a 7.7% decrease when light-exposed, while folate showed a 1.7% average decrease when light-exposed and a 1.0% decrease when light-protected. Neither of these values differed significantly between light-exposed or light-protected. CONCLUSIONS: This study demonstrates there is no need to light-protect specimens prior to vitamin B12 and folate analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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