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1.
Clin Exp Gastroenterol ; 17: 9-23, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38298861

RESUMO

Purpose: The VERSIFY phase 3 trial in patients with Crohn's disease (CD) treated with vedolizumab was the first to include a substudy that used a standardized magnetic resonance enterography (MRE) protocol to assess features of transmural inflammation (bowel edema and wall thickness) and extramural disease activity (enlarged lymph nodes). Patients and Methods: Patients received intravenous vedolizumab (300 mg) at weeks 0 (baseline), 2, and 6, and then every 8 weeks for 26 or 52 weeks. Post hoc analyses included a subpopulation with a Magnetic Resonance Index of Activity score of ≥7 in at least one bowel segment at baseline and at least one postbaseline MRE assessment. Changes in transmural inflammation, including intramural bowel edema and wall thickness, were evaluated. Patient-level and segment-level analyses were performed. Results: MRE images were evaluated in 27 patients with 83 evaluable bowel segments at baseline and week 26, and 13 patients with 38 evaluable segments at baseline, week 26, and week 52. At baseline, all patients had bowel wall edema and wall thickness of >3 mm in at least one bowel segment. The proportion of patients with edema decreased at weeks 26 (17/27 [63.0%]) and 52 (4/13 [30.8%]) and the proportion with bowel wall thickness of >3 mm decreased at weeks 26 (25/27 [92.6%]) and 52 (10/13 [76.9%]). Conclusion: In patients with CD treated with vedolizumab for 26 and 52 weeks, the number of patients, and bowel segments, with MRE-detected transmural inflammation was reduced. These results highlight the impact of vedolizumab on components of transmural inflammation in CD and demonstrate that using MRE in CD multicenter clinical trials is feasible. Trial Registration: ClinicalTrials.gov NCT02425111, April 23, 2015, http://www.clinicaltrials.gov NCT02425111; EU Clinical Trials Register EudraCT 2014-003509-13, https://www.clinicaltrialsregister.eu.

2.
Target Oncol ; 18(3): 403-413, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37103658

RESUMO

BACKGROUND: Off-target central nervous system (CNS) effects are associated with androgen receptor (AR)-targeting treatments for prostate cancer. Darolutamide is a structurally distinct AR inhibitor with low blood-brain barrier penetration. OBJECTIVE: We compared cerebral blood flow (CBF) in grey matter and specific regions related to cognition after darolutamide, enzalutamide, or placebo administration, using arterial spin-label magnetic resonance imaging (ASL-MRI). METHODS: This phase I, randomized, placebo-controlled, three-period crossover study administered single doses of darolutamide, enzalutamide, or placebo to 23 healthy males (aged 18-45 years) at 6-week intervals. ASL-MRI mapped CBF 4 h post-treatment. Treatments were compared using paired t-tests. RESULTS: Drug concentrations during scans confirmed similar unbound exposure of darolutamide and enzalutamide, with complete washout between treatments. A significant localized 5.2% (p = 0.01) and 5.9% (p < 0.001) CBF reduction in the temporo-occipital cortices was observed for enzalutamide versus placebo and versus darolutamide, respectively, with no significant differences for darolutamide versus placebo. Enzalutamide reduced CBF in all prespecified regions, with significant reductions versus placebo (3.9%, p = 0.045) and versus darolutamide (4.4%, p = 0.037) in the left and right dorsolateral prefrontal cortices, respectively. Darolutamide showed minimal changes in CBF versus placebo in cognition-relevant regions. CONCLUSIONS: Darolutamide did not significantly alter CBF, consistent with its low blood-brain barrier penetration and low risk of CNS-related adverse events. A significant reduction in CBF was observed with enzalutamide. These results may be relevant to cognitive function with early and extended use of second-generation AR inhibitors, and warrant further investigation in patients with prostate cancer. TRIAL REGISTRATION NUMBER: NCT03704519; date of registration: October 2018.


Androgens, or male sex hormones, bind to androgen receptors within prostate cells and can cause growth of prostate cancer. The treatment of prostate cancer often includes drugs that bind to androgen receptors, called androgen receptor inhibitors, keeping androgens from binding to the receptors and preventing prostate cancer growth. In clinical studies, these drugs may have adverse effects on the central nervous system, or brain, including dizziness, falls, and impaired thinking and problem solving. This study compared the effects of two androgen receptor inhibitors, darolutamide and enzalutamide, and placebo on blood flow in the brain. Blood flow was measured by a type of magnetic resonance imaging in healthy men after receiving a single dose of treatment. Blood flow in the brain was reduced by enzalutamide compared with both placebo and darolutamide. Darolutamide did not decrease brain blood flow. This lack of effect on brain blood flow is in line with preclinical studies that showed darolutamide's limited ability to cross the blood­brain barrier, which is the naturally occurring barrier that protects the brain from harmful substances. In clinical studies of patients with prostate cancer treated with darolutamide, adverse effects on the brain have occurred in similar proportions of patients receiving darolutamide and placebo. In contrast, enzalutamide treatment has an increased risk of adverse effects on the brain versus placebo. The results of this study provide information on the effects of these androgen receptor inhibitors on brain blood flow that may be related to their adverse effects on the brain and its functioning.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Estudos Cross-Over , Antagonistas de Receptores de Andrógenos/uso terapêutico , Nitrilas/uso terapêutico , Circulação Cerebrovascular
3.
Neuro Oncol ; 24(8): 1219-1229, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35380705

RESUMO

Imaging response assessment is a cornerstone of patient care and drug development in oncology. Clinicians/clinical researchers rely on tumor imaging to estimate the impact of new treatments and guide decision making for patients and candidate therapies. This is important in brain cancer, where associations between tumor size/growth and emerging neurological deficits are strong. Accurately measuring the impact of a new therapy on tumor growth early in clinical development, where patient numbers are small, would be valuable for decision making regarding late-stage development activation. Current attempts to measure the impact of a new therapy have limited influence on clinical development, as determination of progression, stability or response does not currently account for individual tumor growth kinetics prior to the initiation of experimental therapies. Therefore, we posit that imaging-based response assessment, often used as a tool for estimating clinical effect, is incomplete as it does not adequately account for growth trajectories or biological characteristics of tumors prior to the introduction of an investigational agent. Here, we propose modifications to the existing framework for evaluating imaging assessment in primary brain tumors that will provide a more reliable understanding of treatment effects. Measuring tumor growth trajectories prior to a given intervention may allow us to more confidently conclude whether there is an anti-tumor effect. This updated approach to imaging-based tumor response assessment is intended to improve our ability to select candidate therapies for later-stage development, including those that may not meet currently sought thresholds for "response" and ultimately lead to identification of effective treatments.


Assuntos
Neoplasias Encefálicas , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/tratamento farmacológico , Ensaios Clínicos como Assunto , Diagnóstico por Imagem , Humanos , Resultado do Tratamento
4.
J Nucl Med ; 63(11): 1715-1721, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35422447

RESUMO

The mesothelin (MSLN)-targeted 227Th conjugate is a novel α-therapy developed to treat MSLN-overexpressing cancers. We radiolabeled the same antibody-chelator conjugate with 89Zr to evaluate whether PET imaging with 89Zr-MSLN matches 227Th-MSLN tumor uptake, biodistribution, and antitumor activity. Methods: Serial PET imaging with protein doses of 4, 20, or 40 µg of 89Zr-MSLN and 89Zr-control was performed up to 168 h after tracer injection in human tumor-bearing nude mice with high (HT29-MSLN) and low (BxPc3) MSLN expression. 89Zr-MSLN and 227Th-MSLN ex vivo tumor uptake and biodistribution were compared at 6 time points in HT29-MSLN and in medium-MSLN-expressing (OVCAR-3) tumor-bearing mice. 89Zr-MSLN PET imaging was performed before 227Th-MSLN treatment in HT29-MSLN and BxPc3 tumor-bearing mice. Results: 89Zr-MSLN PET imaging showed an SUVmean of 2.2 ± 0.5 in HT29-MSLN tumors. Ex vivo tumor uptake was 10.6% ± 2.4% injected dose per gram at 168 h. 89Zr-MSLN tumor uptake was higher than uptake of 89Zr-control (P = 0.0043). 89Zr-MSLN and 227Th-MSLN showed comparable tumor uptake and biodistribution in OVCAR-3 and HT29-MSLN tumor-bearing mice. Pretreatment SUVmean was 2.2 ± 0.2 in HT29-MSLN tumors, which decreased in volume on 227Th-MSLN treatment. BxPc3 tumors showed an SUVmean of 1.2 ± 0.3 and remained similar in size after 227Th-MSLN treatment. Conclusion: 89Zr-MSLN PET imaging reflected MSLN expression and matched 227Th-MSLN tumor uptake and biodistribution. Our data support the clinical exploration of 89Zr-MSLN PET imaging together with 227Th-MSLN therapy, both using the same antibody-chelator conjugate.


Assuntos
Imunoconjugados , Neoplasias Ovarianas , Animais , Humanos , Camundongos , Feminino , Mesotelina , Camundongos Nus , Distribuição Tecidual , Apoptose , Linhagem Celular Tumoral , Zircônio/uso terapêutico , Tomografia por Emissão de Pósitrons/métodos , Quelantes
5.
Eur J Nucl Med Mol Imaging ; 49(4): 1148-1156, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34651220

RESUMO

PURPOSE: Cholesterol 24-hydroxylase (CH24H) is a brain-specific enzyme that plays a major role in brain cholesterol homeostasis by converting cholesterol into 24S-hydroxycholesterol. The selective CH24H inhibitor soticlestat (TAK-935) is being pursued as a drug for treatment of seizures in developmental and epileptic encephalopathies. Herein, we describe the successful discovery and the preclinical validation of the novel radiolabeled CH24H ligand (3-[18F]fluoroazetidin-1-yl){1-[4-(4-fluorophenyl)pyrimidin-5-yl]piperidin-4-yl}methanone ([18F]T-008) and its tritiated analog, [3H]T-008. METHODS: In vitro autoradiography (ARG) studies in the CH24H wild-type (WT) and knockout (KO) mouse brain sections were conducted using [3H]T-008. PET imaging was conducted in two adult rhesus macaques using [18F]T-008. Each macaque received two test-retest baseline scans and a series of two blocking doses of soticlestat administered prior to [18F]T-008 to determine the CH24H enzyme occupancy. PET data were analyzed with Logan graphical analysis using plasma input. A Lassen plot was applied to estimate CH24H enzyme occupancy by soticlestat. RESULTS: In ARG studies, binding of [3H]T-008 was specific to CH24H in the mouse brain sections, which was not observed in CH24H KO or in wild-type mice after pretreatment with soticlestat. In rhesus PET studies, the rank order of [18F]T-008 uptake was striatum > cortical regions > cerebellum, which was consistent with CH24H distribution in the brain. Pre-blocking with soticlestat reduced the maximum uptake and increased the washout in all brain regions in a dose-dependent manner. Calculated global occupancy values for soticlestat at a dose of 0.89 mg/kg were 97-98%, indicating maximum occupancy. CONCLUSION: The preclinical in vitro and in vivo evaluation of labeled T-008 demonstrates that [18F]T-008 is suitable for imaging CH24H in the brain and warrants further studies in humans.


Assuntos
Piperidinas , Tomografia por Emissão de Pósitrons , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Colesterol 24-Hidroxilase/metabolismo , Humanos , Macaca mulatta/metabolismo , Camundongos , Tomografia por Emissão de Pósitrons/métodos , Piridinas
6.
Cancer Biother Radiopharm ; 36(4): 316-325, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34014767

RESUMO

Introduction: [227Th]Th-3,2-HOPO-MSLN-mAb, a mesothelin (MSLN)-targeted thorium-227 therapeutic conjugate, is currently in phase I clinical trial; however, direct PET imaging using this conjugate is technically challenging. Thus, using the same MSLN antibody, we synthesized 3,2-HOPO and deferoxamine (DFO)-based zirconium-89 antibody conjugates, [89Zr]Zr-3,2-HOPO-MSLN-mAb and [89Zr]Zr-DFO-MSLN-mAb, respectively, and compared them in vitro and in vivo. Methods: [89Zr]Zr-3,2-HOPO-MSLN-mAb and [89Zr]Zr-DFO-MSLN-mAb were evaluated in vitro to determine binding affinity and immunoreactivity in HT29-MSLN and PDX (NCI-Meso16, NCI-Meso21) cells. For both the zirconium-89 conjugates, in vivo studies (biodistribution/imaging) were performed at days 1, 3, and 6, from which tissue uptake was determined. Results: Both the conjugates demonstrated a low nanomolar binding affinity for MSLN and >95% immunoreactivity. In all the three tumor types, biodistribution of [89Zr]Zr-DFO-MSLN-mAb resulted in higher tumor uptake(15.88-28-33%ID/g) at all time points compared with [89Zr]Zr-3,2-HOPO-MSLN-mAb(7-13.07%ID/g). [89Zr]Zr-3,2-HOPO-MSLN-mAb femur uptake was always higher than [89Zr]Zr-DFO-MSLN-mAb, and imaging results concurred with the biodistribution studies. Conclusions: Even though the conjugates exhibited a high binding affinity for MSLN, [89Zr]Zr-DFO-MSLN-mAb showed a higher tumor and lower femur uptake than [89Zr]Zr-3,2-HOPO-MSLN-mAb. Nevertheless, [89Zr]Zr-3,2-HOPO-MSLN-mAb could be used to study organ distribution and lesion uptake with the caveat of detecting MSLN-positive bone lesions. Clinical trial (NCT03507452).


Assuntos
Quelantes/uso terapêutico , Desferroxamina/uso terapêutico , Imunoconjugados/uso terapêutico , Maitansina/análogos & derivados , Radioisótopos/uso terapêutico , Zircônio/uso terapêutico , Animais , Quelantes/farmacologia , Desferroxamina/farmacologia , Feminino , Humanos , Imunoconjugados/farmacologia , Maitansina/farmacologia , Maitansina/uso terapêutico , Mesotelina , Camundongos , Camundongos Nus , Radioisótopos/farmacologia , Zircônio/farmacologia
7.
Neuro Oncol ; 23(2): 189-198, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33130879

RESUMO

Determination of therapeutic benefit in intracranial tumors is intimately dependent on serial assessment of radiographic images. The Response Assessment in Neuro-Oncology (RANO) criteria were established in 2010 to provide an updated framework to better characterize tumor response to contemporary treatments. Since this initial update a number of RANO criteria have provided some basic principles for the interpretation of changes on MR images; however, the details of how to operationalize RANO and other criteria for use in clinical trials are ambiguous and not standardized. In this review article designed for the neuro-oncologist or treating clinician, we outline essential steps for performing radiographic assessments by highlighting primary features of the Imaging Charter (referred to as the Charter for the remainder of this article), a document that describes the clinical trial imaging methodology and methods to ensure operationalization of the Charter into the workings of a clinical trial. Lastly, we provide recommendations for specific changes to optimize this methodology for neuro-oncology, including image registration, requirement of growing tumor for eligibility in trials of recurrent tumor, standardized image acquisition guidelines, and hybrid reader paradigms that allow for both unbiased measurements and more comprehensive interpretation.


Assuntos
Neoplasias Encefálicas , Laboratórios , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/terapia , Diagnóstico por Imagem , Humanos
8.
Radiology ; 285(1): 92-100, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28530847

RESUMO

Purpose To perform a meta-analysis to generate an estimate of the repeatability coefficient (RC) for magnetic resonance (MR) elastography of the liver. Materials and Methods A systematic search of databases was performed for publications on MR elastography during the 10-year period between 2006 and 2015. The identified studies were screened independently and were verified reciprocally by all authors. Two reviewers independently determined the percentage RC and effective sample size from each article. A forest plot was constructed of the percentage RC estimates from the 12 studies. Bootstrap 95% confidence intervals (CIs) were constructed for the summary percentage RCs. Results Twelve studies comprising 274 patients met the eligibility criteria and were included for analysis. A flow diagram of studies included according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was prepared for the inclusion and exclusion criteria. All studies included in the meta-analysis fulfilled four or more of the seven categories of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2. The estimated summary RC was 22% (95% CI: 16.1%, 28.2%). The three main sources for this heterogeneity were the trained versus untrained operator drawing contours to choose regions of interest, the time between two replicate examinations, and, finally, the field strength of the MR imaging unit. The RC estimates tended to be higher for studies that did not use a well-trained operator, those with 1.5-T field strength imaging units, and those with longer time intervals between examinations. Conclusion The meta-analysis results provide the basis for the following draft longitudinal Quantitative Imaging Biomarkers Alliance MR elastography claim: A measured change in hepatic stiffness of 22% or greater, at the same site and with use of the same equipment and acquisition sequence, indicates that a true change in stiffness has occurred with 95% confidence. © RSNA, 2017.


Assuntos
Técnicas de Imagem por Elasticidade , Fígado/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise por Conglomerados , Técnicas de Imagem por Elasticidade/métodos , Técnicas de Imagem por Elasticidade/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto Jovem
9.
Alzheimers Dement (N Y) ; 2(2): 99-109, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29067297

RESUMO

The Alzheimer's Association's Research roundtable met in April 2015 to explore the role of neuroinflammatory mechanisms in the progression of Alzheimer's disease (AD). The ability of innate immune cells, particularly microglia and astrocytes, to mediate neuroinflammation in AD has been implicated as a significant contributor to disease pathogenesis. Adaptive immunity, which plays an important role in responding to injury and some diseases of the central nervous system, may contribute to neuroinflammation in AD as well. Communication between the central and peripheral immune systems may also be important in AD. An increased understanding of the physiology of the innate immune system may aid the identification of new therapeutic targets or mechanisms. The development of predictive animal models and translatable neuroinflammation biomarkers for AD would also facilitate the advancement of novel treatments for innate immunity. Important challenges impeding the advancement of new therapeutic agents and strategies to overcome them were discussed.

10.
BMC Physiol ; 15: 4, 2015 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-26449218

RESUMO

BACKGROUND: Neurogenic pulmonary edema (NPE) is a non-cardiogenic form of pulmonary edema that can occur consequent to central neurologic insults including stroke, traumatic brain injury, and seizure. NPE is a public health concern due to high morbidity and mortality, yet the mechanism(s) are unknown. We hypothesized that NPE, evoked by cerebral hypoxia in the presence of systemic normoxia, would be accompanied by sympathetic activation, oxidative stress, and compensatory antioxidant mechanisms. METHODS: Thirteen Walker hounds were assigned to cerebral hypoxia (SaO2 ~ 55 %) with systemic normoxia (SaO2 ~ 90 %) (CH; n = 6), cerebral and systemic (global) hypoxia (SaO2 ~ 60 %) (GH; n = 4), or cerebral and systemic normoxia (SaO2 ~ 90 %) (CON; n = 3). Femoral venous (CH and CON) perfusate was delivered via cardiopulmonary bypass to the brain and GH was induced by FiO2 = 10 % to maintain the SaO2 at ~60 %. Lung wet to lung dry weight ratios (LWW/LDW) were assessed as an index of pulmonary edema in addition to hemodynamic measurements. Plasma catecholamines were measured as markers of sympathetic nervous system (SNS) activity. Total glutathione, protein carbonyls, and malondialdehyde were assessed as indicators of oxidative stress. Brain and lung compensatory antioxidants were measured with immunoblotting. RESULTS: Compared to CON, LWW/LDW and pulmonary artery pressure were greater in CH and GH. Expression of hemeoxygenase-1 in brain was higher in CH compared to GH and CON, despite no group differences in oxidative damage in any tissue. Catecholamines tended to be higher in CH and GH. CONCLUSION: Cerebral hypoxia, with systemic normoxia, is not systematically associated with an increase in oxidative stress and compensatory antioxidant enzymes in lung, suggesting oxidative stress did not contribute to NPE in lung. However, increased SNS activity may play a role in the induction of NPE during hypoxia.


Assuntos
Circulação Cerebrovascular/fisiologia , Hipóxia Encefálica/metabolismo , Estresse Oxidativo/fisiologia , Edema Pulmonar/metabolismo , Sistema Nervoso Simpático/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Cães , Glutationa/metabolismo , Hemodinâmica/fisiologia , Hipóxia Encefálica/fisiopatologia , Pulmão/metabolismo , Pulmão/fisiopatologia , Masculino , Malondialdeído/metabolismo , Edema Pulmonar/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia
11.
Alzheimers Dement ; 11(7): 840-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26194317

RESUMO

The Alzheimer's Disease Neuroimaging Initiative (ADNI) Private Partner Scientific Board (PPSB) is comprised of representatives of private, for-profit entities (including pharmaceutical, biotechnology, diagnostics, imaging companies, and imaging contract research organizations), and nonprofit organizations that provide financial and scientific support to ADNI through the Foundation for the National Institutes of Health. The PPSB serves as an independent, open, and precompetitive forum in which all private sector and not-for-profit partners in ADNI can collaborate, share information, and offer scientific and private-sector perspectives and expertise on issues relating to the ADNI project. In this article, we review and highlight the role, activities, and contributions of the PPSB within the ADNI project, and provide a perspective on remaining unmet needs and future directions.


Assuntos
Doença de Alzheimer/diagnóstico , Consultores , Neuroimagem/métodos , Parcerias Público-Privadas , Doença de Alzheimer/complicações , Biotecnologia , Transtornos Cognitivos/etiologia , Indústria Farmacêutica , Humanos , Estados Unidos
12.
Stat Methods Med Res ; 24(1): 27-67, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24919831

RESUMO

Technological developments and greater rigor in the quantitative measurement of biological features in medical images have given rise to an increased interest in using quantitative imaging biomarkers to measure changes in these features. Critical to the performance of a quantitative imaging biomarker in preclinical or clinical settings are three primary metrology areas of interest: measurement linearity and bias, repeatability, and the ability to consistently reproduce equivalent results when conditions change, as would be expected in any clinical trial. Unfortunately, performance studies to date differ greatly in designs, analysis method, and metrics used to assess a quantitative imaging biomarker for clinical use. It is therefore difficult or not possible to integrate results from different studies or to use reported results to design studies. The Radiological Society of North America and the Quantitative Imaging Biomarker Alliance with technical, radiological, and statistical experts developed a set of technical performance analysis methods, metrics, and study designs that provide terminology, metrics, and methods consistent with widely accepted metrological standards. This document provides a consistent framework for the conduct and evaluation of quantitative imaging biomarker performance studies so that results from multiple studies can be compared, contrasted, or combined.


Assuntos
Biomarcadores , Diagnóstico por Imagem , Projetos de Pesquisa , Estatística como Assunto , Viés , Ensaios Clínicos como Assunto , Humanos , Reprodutibilidade dos Testes , Terminologia como Assunto
13.
Alzheimers Dement ; 11(9): 1050-68, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25457431

RESUMO

In vivo imaging of amyloid burden with positron emission tomography (PET) provides a means for studying the pathophysiology of Alzheimer's and related diseases. Measurement of subtle changes in amyloid burden requires quantitative analysis of image data. Reliable quantitative analysis of amyloid PET scans acquired at multiple sites and over time requires rigorous standardization of acquisition protocols, subject management, tracer administration, image quality control, and image processing and analysis methods. We review critical points in the acquisition and analysis of amyloid PET, identify ways in which technical factors can contribute to measurement variability, and suggest methods for mitigating these sources of noise. Improved quantitative accuracy could reduce the sample size necessary to detect intervention effects when amyloid PET is used as a treatment end point and allow more reliable interpretation of change in amyloid burden and its relationship to clinical course.


Assuntos
Amiloide/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Humanos , Tomografia por Emissão de Pósitrons/instrumentação , Compostos Radiofarmacêuticos
14.
Alzheimers Dement ; 10(4): 421-429.e3, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24985687

RESUMO

BACKGROUND: Regulatory qualification of a biomarker for a defined context of use provides scientifically robust assurances to sponsors and regulators that accelerate appropriate adoption of biomarkers into drug development. METHODS: The Coalition Against Major Diseases submitted a dossier to the Scientific Advice Working Party of the European Medicines Agency requesting a qualification opinion on the use of hippocampal volume as a biomarker for enriching clinical trials in subjects with mild cognitive impairment, incorporating a scientific rationale, a literature review and a de novo analysis of Alzheimer's Disease Neuroimaging Initiative data. RESULTS: The literature review and de novo analysis were consistent with the proposed context of use, and the Committee for Medicinal Products for Human Use released an opinion in November 2011. CONCLUSIONS: We summarize the scientific rationale and the data that supported the first qualification of an imaging biomarker by the European Medicines Agency.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/terapia , Ensaios Clínicos como Assunto , Hipocampo/patologia , Disfunção Cognitiva , Bases de Dados Factuais/estatística & dados numéricos , Progressão da Doença , Europa (Continente) , Humanos , Neuroimagem , Modelos de Riscos Proporcionais , Curva ROC
15.
Alzheimers Dement ; 10(4): 430-438.e2, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24985688

RESUMO

BACKGROUND: Low HCV has recently been qualified by the European Medicines Agency as a biomarker for enrichment of clinical trials in predementia stages of Alzheimer's disease. For automated methods to meet the necessary regulatory requirements, it is essential they be standardized and their performance be well characterized. METHODS: The within-image and between-field strength reproducibility of automated hippocampal volumetry using the Learning Embeddings for Atlas Propagation (or LEAP) algorithm was assessed on 153 Alzheimer's Disease Neuroimaging Initiative subjects. RESULTS: Tests/retests at 1.5 T and 3 T, and a comparison between 1.5 T and 3 T, yielded average unsigned variabilities in HCVs of 1.51%, 1.52%, and 2.68%. A small bias between field strengths (mean signed difference, 1.17%; standard deviation, 3.07%) was observed. CONCLUSIONS: The measured reproducibility characteristics confirm the suitability of using automated magnetic resonance imaging analyses to assess HCVs quantitatively and to represent a fundamental characterization that is critical to meet the regulatory requirements for using hippocampal volumetry in clinical trials and health care.


Assuntos
Doença de Alzheimer/diagnóstico , Hipocampo/patologia , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Disfunção Cognitiva/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Entrevista Psiquiátrica Padronizada , Reprodutibilidade dos Testes
16.
Neurobiol Aging ; 35(4): 808-18, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24211008

RESUMO

The objective of this study was to evaluate the effect of computational algorithm, measurement variability, and cut point on hippocampal volume (HCV)-based patient selection for clinical trials in mild cognitive impairment (MCI). We used normal control and amnestic MCI subjects from the Alzheimer's Disease Neuroimaging Initiative 1 (ADNI-1) as normative reference and screening cohorts. We evaluated the enrichment performance of 4 widely used hippocampal segmentation algorithms (FreeSurfer, Hippocampus Multi-Atlas Propagation and Segmentation (HMAPS), Learning Embeddings Atlas Propagation (LEAP), and NeuroQuant) in terms of 2-year changes in Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), and Clinical Dementia Rating Sum of Boxes (CDR-SB). We modeled the implications for sample size, screen fail rates, and trial cost and duration. HCV based patient selection yielded reduced sample sizes (by ∼40%-60%) and lower trial costs (by ∼30%-40%) across a wide range of cut points. These results provide a guide to the choice of HCV cut point for amnestic MCI clinical trials, allowing an informed tradeoff between statistical and practical considerations.


Assuntos
Algoritmos , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/patologia , Hipocampo/patologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer , Biomarcadores , Ensaios Clínicos como Assunto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroimagem , Testes Neuropsicológicos , Seleção de Pacientes , Tamanho da Amostra
17.
Zoo Biol ; 32(4): 427-35, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23649664

RESUMO

Evidence is mounting that personality is associated with health and well-being in humans and other animals. In a step towards increasing our understanding of this link, we applied regulatory focus theory, a motivational perspective from social psychology, to the behavior of zoo-housed cotton top tamarins. We tested whether regulatory focus "personality," that is stable differences in whether an individual is motivated by gains versus safety, would 1) produce individual differences in behavior and 2) predict how individuals interact with enrichment. First, we characterized individuals with respect to several key behaviors: eating in the open, hiding, and time spent near the front of the exhibit. The monkeys were consistent in their behavioral tendencies across the 6-month study, allowing regulatory focus classification. One monkey showed evidence of being a promotion-individual, that is, more motivated by gains than safety. One monkey showed evidence of being a prevention-individual, that is, more motivated by safety than gains. The other monkeys were stable in their behavior and showed evidence of being intermediate-individuals, that is, they favored neither gains nor safety. Using these characterizations, we predicted distinct patterns of individual-object interactions with enrichment. For example, we predicted that a promotion-individual (favoring gains over safety) would approach potential gains faster than a prevention-individual (favoring safety over gains). Counter-intuitively, however, we also predicted that a promotion-individual would approach non-gains slower than a prevention-individual concerned with safety. We found support for our predictions, which suggests that regulatory focus theory could be a useful tool for understanding how and why individuals interact with environmental enrichment.


Assuntos
Criação de Animais Domésticos/métodos , Animais de Zoológico , Comportamento Animal , Personalidade , Saguinus/fisiologia , Animais , Feminino , Masculino
18.
Alzheimers Dement ; 9(3): 332-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23110865

RESUMO

The Alzheimer's Disease Neuroimaging Initiative (ADNI) three-dimensional T1-weighted magnetic resonance imaging (MRI) acquisitions provide a rich data set for developing and testing analysis techniques for extracting structural endpoints. To promote greater rigor in analysis and meaningful comparison of different algorithms, the ADNI MRI Core has created standardized analysis sets of data comprising scans that met minimum quality control requirements. We encourage researchers to test and report their techniques against these data. Standard analysis sets of volumetric scans from ADNI-1 have been created, comprising screening visits, 1-year completers (subjects who all have screening, 6- and 12-month scans), 2-year annual completers (screening, 1-year and 2-year scans), 2-year completers (screening, 6-months, 1-year, 18-months [mild cognitive impaired (MCI) only], and 2-year scans), and complete visits (screening, 6-month, 1-year, 18-month [MCI only], 2-year, and 3-year [normal and MCI only] scans). As the ADNI-GO/ADNI-2 data become available, updated standard analysis sets will be posted regularly.


Assuntos
Algoritmos , Doença de Alzheimer/patologia , Disfunção Cognitiva/patologia , Bases de Dados Factuais/normas , Imageamento por Ressonância Magnética/normas , Idoso , Humanos , Imageamento por Ressonância Magnética/métodos , Padrões de Referência , Reprodutibilidade dos Testes
19.
J Marital Fam Ther ; 38 Suppl 1: 63-71, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22765325

RESUMO

The purpose of this article is to encourage family therapists to become more interested in family business practice. It does so in three ways: (a) highlighting the number of therapists already involved in family business issues; (b) showing the parallels between family business and family therapy by applying family business research findings to couples therapy; (c) discussing how family therapists already have the practice wisdom to be effective in working with family business clients. Limitations of this practice are also discussed along with suggestions for overcoming them.


Assuntos
Comércio , Terapia Familiar , Família/psicologia , Competência Clínica , Comércio/organização & administração , Terapia de Casal/métodos , Emoções , Terapia Familiar/métodos , Feminino , Humanos , Masculino , Casamento/psicologia , Confiança/psicologia
20.
J Vet Diagn Invest ; 24(4): 759-62, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22621950

RESUMO

Hemorrhagic splenic masses diagnosed as hemangioma or hemangiosarcoma were reviewed. Lymphoid hyperplasia was present in none of the hemangiosarcoma cases and in 27% of the hematoma cases. Siderotic nodules in the capsule or trabeculae were present in 25% of hemangiosarcoma cases and in 36% of hematoma cases. Hemoabdomen was noted in the clinical history of 54% of hemangiosarcoma cases and in 22% of hematoma cases. The average age (10.3 and 9.6 years, respectively), sex ratios (slightly more males), and most common breeds (Labrador Retriever, Golden Retriever, and German Shepherd Dog) were similar for the hemangiosarcoma and hematoma cases. Since lymphoid hyperplasia is much more common in cases of hematoma, the presence of this feature lends support to a diagnosis of hematoma rather than hemangiosarcoma. Signalment, history of hemoabdomen, and presence of siderotic nodules do not point to one diagnosis over the other.


Assuntos
Doenças do Cão/patologia , Hemangiossarcoma/veterinária , Hematoma/veterinária , Neoplasias Esplênicas/veterinária , Animais , Cães , Feminino , Hemangiossarcoma/patologia , Hematoma/patologia , Masculino , Estudos Retrospectivos , Neoplasias Esplênicas/patologia
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