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1.
Epidemiology ; 35(2): 164-173, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38290139

RESUMEN

BACKGROUND: In the United States, over 80% of tuberculosis (TB) disease cases are estimated to result from reactivation of latent TB infection (LTBI) acquired more than 2 years previously ("reactivation TB"). We estimated reactivation TB rates for the US population with LTBI, overall, by age, sex, race-ethnicity, and US-born status, and for selected comorbidities (diabetes, end-stage renal disease, and HIV). METHODS: We collated nationally representative data for 2011-2012. Reactivation TB incidence was based on TB cases reported to the National TB Surveillance System that were attributed to LTBI reactivation. Person-years at risk of reactivation TB were calculated using interferon-gamma release assay (IGRA) positivity from the National Health and Nutrition Examination Survey, published values for interferon-gamma release assay sensitivity and specificity, and population estimates from the American Community Survey. RESULTS: For persons aged ≥6 years with LTBI, the overall reactivation rate was estimated as 0.072 (95% uncertainty interval: 0.047, 0.12) per 100 person-years. Estimated reactivation rates declined with age. Compared to the overall population, estimated reactivation rates were higher for persons with diabetes (adjusted rate ratio [aRR] = 1.6 [1.5, 1.7]), end-stage renal disease (aRR = 9.8 [5.4, 19]), and HIV (aRR = 12 [10, 13]). CONCLUSIONS: In our study, individuals with LTBI faced small, non-negligible risks of reactivation TB. Risks were elevated for individuals with medical comorbidities that weaken immune function.


Asunto(s)
Diabetes Mellitus , Infecciones por VIH , Fallo Renal Crónico , Mycobacterium tuberculosis , Tuberculosis , Humanos , Estados Unidos/epidemiología , Encuestas Nutricionales , Tuberculosis/epidemiología , Tuberculosis/diagnóstico , Fallo Renal Crónico/epidemiología , Infecciones por VIH/epidemiología
2.
bioRxiv ; 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-37162914

RESUMEN

Dimensionality reduction is a critical step in the analysis of single-cell RNA-seq (scRNA-seq) data. The standard approach is to apply a transformation to the count matrix followed by principal components analysis (PCA). However, this approach can induce spurious heterogeneity and mask true biological variability. An alternative approach is to directly model the counts, but existing methods tend to be computationally intractable on large datasets and do not quantify uncertainty in the low-dimensional representation. To address these problems, we develop scGBM, a novel method for model-based dimensionality reduction of scRNA-seq data using a Poisson bilinear model. We introduce a fast estimation algorithm to fit the model using iteratively reweighted singular value decompositions, enabling the method to scale to datasets with millions of cells. Furthermore, scGBM quantifies the uncertainty in each cell's latent position and leverages these uncertainties to assess the confidence associated with a given cell clustering. On real and simulated single-cell data, we find that scGBM produces low-dimensional embeddings that better capture relevant biological information while removing unwanted variation.

3.
Cancer Res ; 83(20): 3442-3461, 2023 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-37470810

RESUMEN

Although external beam radiotherapy (xRT) is commonly used to treat central nervous system (CNS) tumors in patients of all ages, young children treated with xRT frequently experience life-altering and dose-limiting neurocognitive impairment (NI) while adults do not. The lack of understanding of mechanisms responsible for these differences has impeded the development of neuroprotective treatments. Using a newly developed mouse model of xRT-induced NI, we found that neurocognitive function is impaired by ionizing radiation in a dose- and age-dependent manner, with the youngest animals being most affected. Histologic analysis revealed xRT-driven neuronal degeneration and cell death in neurogenic brain regions in young animals but not adults. BH3 profiling showed that neural stem and progenitor cells, neurons, and astrocytes in young mice are highly primed for apoptosis, rendering them hypersensitive to genotoxic damage. Analysis of single-cell RNA sequencing data revealed that neural cell vulnerability stems from heightened expression of proapoptotic genes including BAX, which is associated with developmental and mitogenic signaling by MYC. xRT induced apoptosis in primed neural cells by triggering a p53- and PUMA-initiated, proapoptotic feedback loop requiring cleavage of BID and culminating in BAX oligomerization and caspase activation. Notably, loss of BAX protected against apoptosis induced by proapoptotic signaling in vitro and prevented xRT-induced apoptosis in neural cells in vivo as well as neurocognitive sequelae. On the basis of these findings, preventing xRT-induced apoptosis specifically in immature neural cells by blocking BAX, BIM, or BID via direct or upstream mechanisms is expected to ameliorate NI in pediatric patients with CNS tumor. SIGNIFICANCE: Age- and differentiation-dependent apoptotic priming plays a pivotal role in driving radiotherapy-induced neurocognitive impairment and can be targeted for neuroprotection in pediatric patients.


Asunto(s)
Proteínas Reguladoras de la Apoptosis , Apoptosis , Animales , Niño , Preescolar , Humanos , Ratones , Apoptosis/fisiología , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Muerte Celular , Transducción de Señal , Proteína p53 Supresora de Tumor/genética
4.
Brain Commun ; 5(3): fcad106, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37265597

RESUMEN

X-linked dystonia parkinsonism is a neurodegenerative movement disorder that affects men whose mothers originate from the island of Panay, Philippines. Current evidence indicates that the most likely cause is an expansion in the TAF1 gene that may be amenable to treatment. To prepare for clinical trials of therapeutic candidates for X-linked dystonia parkinsonism, we focused on the identification of quantitative phenotypic measures that are most strongly associated with disease progression. Our main objective is to establish a comprehensive, quantitative assessment of movement dysfunction and bulbar motor impairments that are sensitive and specific to disease progression in persons with X-linked dystonia parkinsonism. These measures will set the stage for future treatment trials. We enrolled patients with X-linked dystonia parkinsonism and performed a comprehensive oromotor, speech and neurological assessment. Measurements included patient-reported questionnaires regarding daily living activities and both neurologist-rated movement scales and objective quantitative measures of bulbar function and nutritional status. Patients were followed for 18 months from the date of enrollment and evaluated every 6 months during that period. We analysed a total of 87 men: 29 were gene-positive and had symptoms at enrollment, seven were gene-positive and had no symptoms at enrollment and 51 were gene-negative. We identified measures that displayed a significant change over the study. We used principal variables analysis to identify a minimal battery of 21 measures that explains 67.3% of the variance over the course of the study. These measures included patient-reported, clinician-rated and objective quantitative outcomes that may serve as endpoints in future clinical trials.

5.
J Mach Learn Res ; 24(23)2023.
Artículo en Inglés | MEDLINE | ID: mdl-37206375

RESUMEN

Insights into complex, high-dimensional data can be obtained by discovering features of the data that match or do not match a model of interest. To formalize this task, we introduce the "data selection" problem: finding a lower-dimensional statistic-such as a subset of variables-that is well fit by a given parametric model of interest. A fully Bayesian approach to data selection would be to parametrically model the value of the statistic, nonparametrically model the remaining "background" components of the data, and perform standard Bayesian model selection for the choice of statistic. However, fitting a nonparametric model to high-dimensional data tends to be highly inefficient, statistically and computationally. We propose a novel score for performing data selection, the "Stein volume criterion (SVC)", that does not require fitting a nonparametric model. The SVC takes the form of a generalized marginal likelihood with a kernelized Stein discrepancy in place of the Kullback-Leibler divergence. We prove that the SVC is consistent for data selection, and establish consistency and asymptotic normality of the corresponding generalized posterior on parameters. We apply the SVC to the analysis of single-cell RNA sequencing data sets using probabilistic principal components analysis and a spin glass model of gene regulation.

6.
Bayesian Anal ; 18(1): 79-104, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36643374

RESUMEN

Bayesian model selection is premised on the assumption that the data are generated from one of the postulated models. However, in many applications, all of these models are incorrect (that is, there is misspecification). When the models are misspecified, two or more models can provide a nearly equally good fit to the data, in which case Bayesian model selection can be highly unstable, potentially leading to self-contradictory findings. To remedy this instability, we propose to use bagging on the posterior distribution ("BayesBag") - that is, to average the posterior model probabilities over many bootstrapped datasets. We provide theoretical results characterizing the asymptotic behavior of the posterior and the bagged posterior in the (misspecified) model selection setting. We empirically assess the BayesBag approach on synthetic and real-world data in (i) feature selection for linear regression and (ii) phylogenetic tree reconstruction. Our theory and experiments show that, when all models are misspecified, BayesBag (a) provides greater reproducibility and (b) places posterior mass on optimal models more reliably, compared to the usual Bayesian posterior; on the other hand, under correct specification, BayesBag is slightly more conservative than the usual posterior, in the sense that BayesBag posterior probabilities tend to be slightly farther from the extremes of zero and one. Overall, our results demonstrate that BayesBag provides an easy-to-use and widely applicable approach that improves upon Bayesian model selection by making it more stable and reproducible.

7.
Nat Commun ; 13(1): 5789, 2022 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-36184661

RESUMEN

Immunoglobulin light chain (AL) amyloidosis is an incurable hematologic disorder typically characterized by the production of amyloidogenic light chains by clonal plasma cells. These light chains misfold and aggregate in healthy tissues as amyloid fibrils, leading to life-threatening multi-organ dysfunction. Here we show that the clonal plasma cells in AL amyloidosis are highly primed to undergo apoptosis and dependent on pro-survival proteins MCL-1 and BCL-2. Notably, this MCL-1 dependency is indirectly targeted by the proteasome inhibitor bortezomib, currently the standard of care for this disease and the related plasma cell disorder multiple myeloma, due to upregulation of pro-apoptotic Noxa and its inhibitory binding to MCL-1. BCL-2 inhibitors sensitize clonal plasma cells to multiple front-line therapies including bortezomib, dexamethasone and lenalidomide. Strikingly, in mice bearing AL amyloidosis cell line xenografts, single agent treatment with the BCL-2 inhibitor ABT-199 (venetoclax) produces deeper remissions than bortezomib and triples median survival. Mass spectrometry-based proteomic analysis reveals rewiring of signaling pathways regulating apoptosis, proliferation and mitochondrial metabolism between isogenic AL amyloidosis and multiple myeloma cells that divergently alter their sensitivity to therapies. These findings provide a roadmap for the use of BH3 mimetics to exploit endogenous and induced apoptotic vulnerabilities in AL amyloidosis.


Asunto(s)
Antineoplásicos , Amiloidosis de Cadenas Ligeras de las Inmunoglobulinas , Mieloma Múltiple , Amiloide/uso terapéutico , Animales , Antineoplásicos/farmacología , Bortezomib/farmacología , Bortezomib/uso terapéutico , Compuestos Bicíclicos Heterocíclicos con Puentes , Dexametasona/farmacología , Dexametasona/uso terapéutico , Humanos , Cadenas Ligeras de Inmunoglobulina , Amiloidosis de Cadenas Ligeras de las Inmunoglobulinas/tratamiento farmacológico , Lenalidomida/farmacología , Lenalidomida/uso terapéutico , Ratones , Mieloma Múltiple/tratamiento farmacológico , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Inhibidores de Proteasoma , Proteómica , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Sulfonamidas
8.
Int Arch Occup Environ Health ; 95(8): 1785-1796, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35551477

RESUMEN

PURPOSE: Exposures related to beryllium (Be) are an enduring concern among workers in the nuclear weapons and other high-tech industries, calling for regular and rigorous biological monitoring. Conventional biomonitoring of Be in urine is not informative of cumulative exposure nor health outcomes. Biomarkers of exposure to Be based on non-invasive biomonitoring could help refine disease risk assessment. In a cohort of workers with Be exposure, we employed blood plasma extracellular vesicles (EVs) to discover novel biomarkers of exposure to Be. METHODS: EVs were isolated from plasma using size-exclusion chromatography and subjected to mass spectrometry-based proteomics. A protein-based classifier was developed using LASSO regression and validated by ELISA. RESULTS: We discovered a dual biomarker signature comprising zymogen granule protein 16B and putative protein FAM10A4 that differentiated between Be-exposed and -unexposed subjects. ELISA-based quantification of the biomarkers in an independent cohort of samples confirmed higher expression of the signature in the Be-exposed group, displaying high predictive accuracy (AUROC = 0.919). Furthermore, the biomarkers efficiently discriminated high- and low-exposure groups (AUROC = 0.749). CONCLUSIONS: This is the first report of EV biomarkers associated with Be exposure and exposure levels. The biomarkers could be implemented in resource-limited settings for Be exposure assessment.


Asunto(s)
Berilio , Vesículas Extracelulares , Berilio/metabolismo , Biomarcadores , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo , Humanos , Espectrometría de Masas , Proteómica/métodos
9.
Clin Infect Dis ; 74(9): 1594-1603, 2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-34323959

RESUMEN

BACKGROUND: Older age is a risk factor for tuberculosis (TB) in low incidence settings. Using data from the US National TB Surveillance System and American Community Survey, we estimated trends and racial/ethnic differences in TB incidence among US-born cohorts aged ≥50 years. METHODS: In total, 42 000 TB cases among US-born persons ≥50 years were reported during 2001-2019. We used generalized additive regression models to decompose the effects of birth cohort and age on TB incidence rates, stratified by sex and race/ethnicity. Using genotype-based estimates of recent transmission (available 2011-2019), we implemented additional models to decompose incidence trends by estimated recent versus remote infection. RESULTS: Estimated incidence rates declined with age, for the overall cohort and most sex and race/ethnicity strata. Average annual percentage declines flattened for older individuals, from 8.80% (95% confidence interval [CI] 8.34-9.23) in 51-year-olds to 4.51% (95% CI 3.87-5.14) in 90-year-olds. Controlling for age, incidence rates were lower for more recent birth cohorts, dropping 8.79% (95% CI 6.13-11.26) on average between successive cohort years. Incidence rates were substantially higher for racial/ethnic minorities, and these inequalities persisted across all birth cohorts. Rates from recent infection declined at approximately 10% per year as individuals aged. Rates from remote infection declined more slowly with age, and this annual percentage decline approached zero for the oldest individuals. CONCLUSIONS: TB rates were highest for racial/ethnic minorities and for the earliest birth cohorts and declined with age. For the oldest individuals, annual percentage declines were low, and most cases were attributed to remote infection.


Asunto(s)
Tuberculosis , Niño , Estudios de Cohortes , Etnicidad , Humanos , Incidencia , Vigilancia de la Población , Tuberculosis/epidemiología , Estados Unidos/epidemiología
11.
Nat Commun ; 12(1): 5955, 2021 10 12.
Artículo en Inglés | MEDLINE | ID: mdl-34642316

RESUMEN

Leptomeningeal disease (LMD) is a devastating complication of solid tumor malignancies, with dire prognosis and no effective systemic treatment options. Over the past decade, the incidence of LMD has steadily increased due to therapeutics that have extended the survival of cancer patients, highlighting the need for new interventions. To examine the efficacy of immune checkpoint inhibitors (ICI) in patients with LMD, we completed two phase II clinical trials. Here, we investigate the cellular and molecular features underpinning observed patient trajectories in these trials by applying single-cell RNA and cell-free DNA profiling to longitudinal cerebrospinal fluid (CSF) draws from enrolled patients. We recover immune and malignant cell types in the CSF, characterize cell behavior changes following ICI, and identify genomic features associated with relevant clinical phenomena. Overall, our study describes the liquid LMD tumor microenvironment prior to and following ICI treatment and demonstrates clinical utility of cell-free and single-cell genomic measurements for LMD research.


Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Antígeno CTLA-4/inmunología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Carcinomatosis Meníngea/tratamiento farmacológico , Neoplasias Meníngeas/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/inmunología , Microambiente Tumoral/efectos de los fármacos , Adulto , Anciano , Anticuerpos Monoclonales Humanizados/uso terapéutico , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/secundario , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Antígeno CTLA-4/antagonistas & inhibidores , Antígeno CTLA-4/genética , Ácidos Nucleicos Libres de Células/genética , Ácidos Nucleicos Libres de Células/inmunología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunoterapia , Interferón gamma/genética , Interferón gamma/inmunología , Ipilimumab/uso terapéutico , Masculino , Carcinomatosis Meníngea/inmunología , Carcinomatosis Meníngea/mortalidad , Carcinomatosis Meníngea/patología , Neoplasias Meníngeas/inmunología , Neoplasias Meníngeas/mortalidad , Neoplasias Meníngeas/patología , Persona de Mediana Edad , Nivolumab/uso terapéutico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Receptor de Muerte Celular Programada 1/genética , Análisis de la Célula Individual , Análisis de Supervivencia , Microambiente Tumoral/genética , Microambiente Tumoral/inmunología
12.
PLoS Comput Biol ; 16(11): e1008429, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33253142

RESUMEN

Aging is a complex process with poorly understood genetic mechanisms. Recent studies have sought to classify genes as pro-longevity or anti-longevity using a variety of machine learning algorithms. However, it is not clear which types of features are best for optimizing classification performance and which algorithms are best suited to this task. Further, performance assessments based on held-out test data are lacking. We systematically compare five popular classification algorithms using gene ontology and gene expression datasets as features to predict the pro-longevity versus anti-longevity status of genes for two model organisms (C. elegans and S. cerevisiae) using the GenAge database as ground truth. We find that elastic net penalized logistic regression performs particularly well at this task. Using elastic net, we make novel predictions of pro- and anti-longevity genes that are not currently in the GenAge database.


Asunto(s)
Expresión Génica , Ontología de Genes , Longevidad/genética , Algoritmos , Animales , Caenorhabditis elegans/genética , Genes Fúngicos , Aprendizaje Automático , Reproducibilidad de los Resultados , Saccharomyces cerevisiae/genética
13.
J Clin Neurophysiol ; 36(5): 371-374, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31107715

RESUMEN

PURPOSE: Magnetoencephalography (MEG) is a noninvasive tool used clinically for presurgical evaluation of patients with medically intractable epilepsy. These recordings require patients to lie still for prolonged periods of time in a magnetically shielded room. Children or uncooperative adults with epilepsy may require sedation to reduce movement artefact and obtain high-quality recordings. Potential challenges related to the use of total intravenous anesthesia in the MEG environment include limited access to the patient's airway, remote location, suppression of cortical activity, and increased patient care expenses. We report our experience with intranasal dexmedetomidine as sedation for intractable epilepsy patients undergoing MEG. METHODS: Sleep deprivation occurred the night before MEG testing. Intranasal dexmedetomidine (2 µg/kg) was administered and oxygen saturation, blood pressure, and pulse rate were recorded continuously on a monitor outside the magnetically shielded room. A recording of spontaneous neuromagnetic activity was immediately followed by median nerve electrical stimulation. RESULTS: Twenty-six patients (mean age 12.2 ± 4.2 years) with medically intractable epilepsy were recorded using this protocol. There were no failures of sedation, and although patients experienced transient bradycardia, none required intervention and the recording did not need to be stopped. In all cases, artefact-free MEG recordings were obtained with sufficient interictal discharges available for source analysis. CONCLUSIONS: Our experience suggests that intranasal dexmedetomidine is an advantageous sedation option for children and adults with intractable epilepsy who are undergoing MEG. Further research is needed to determine the best ways to apply these methods to younger children and those with developmental disabilities.


Asunto(s)
Dexmedetomidina/administración & dosificación , Epilepsia Refractaria/diagnóstico , Epilepsia Refractaria/tratamiento farmacológico , Hipnóticos y Sedantes/administración & dosificación , Magnetoencefalografía/métodos , Administración Intranasal , Adolescente , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Niño , Epilepsia Refractaria/fisiopatología , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Estudios Retrospectivos
14.
Oper Neurosurg (Hagerstown) ; 16(2): 60-66, 2019 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-29790970

RESUMEN

BACKGROUND AND IMPORTANCE: Aneurysms of the ophthalmic artery (OA) within the orbit and optic canal are extremely rare. Given the peripheral location of these aneurysms and the fact that most are fusiform, parent artery occlusion is preferred for symptomatic aneurysms. However, the impact of OA occlusion on vision is not always innocuous. Balloon occlusion testing (BOT) of the OA has the potential to gauge the possibility of visual compromise, in addition to assessing collaterals. While BOT has been assessed for carotid artery occlusion, its role in OA occlusion has not been well defined. CLINICAL PRESENTATION: We describe a patient with a 6-mm intracanalicular OA aneurysm who was treated with endovascular coil embolization of the aneurysm and occlusion of the parent artery. We performed a 30-min balloon occlusion test, in which we verified intact visual and neurological function. Collateral vascularity was confirmed. Complete occlusion was achieved and the patient recovered with intact visual and neurological function. We provide a review of literature pertaining to parent artery occlusion of OA aneurysms that occur within optic canal and orbit. A brief note on anatomy of OA and collaterals is provided. CONCLUSION: Endovascular parent artery occlusion is an effective treatment for OA aneurysms that occur in optic canal and orbit. Assessment of effect of occlusion on vision is important. BOT can assess this and provide valuable information. Recovery or preservation of visual function is highly dependent on preoperative visual status.


Asunto(s)
Oclusión con Balón/métodos , Arterias Carótidas/diagnóstico por imagen , Circulación Colateral , Aneurisma Intracraneal/diagnóstico por imagen , Arteria Oftálmica/diagnóstico por imagen , Angiografía Cerebral , Embolización Terapéutica/métodos , Procedimientos Endovasculares/métodos , Humanos , Aneurisma Intracraneal/terapia , Cuidados Intraoperatorios , Masculino , Persona de Mediana Edad , Trastornos de la Visión/prevención & control
15.
J Am Stat Assoc ; 114(527): 1113-1125, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31942084

RESUMEN

The standard approach to Bayesian inference is based on the assumption that the distribution of the data belongs to the chosen model class. However, even a small violation of this assumption can have a large impact on the outcome of a Bayesian procedure. We introduce a novel approach to Bayesian inference that improves robustness to small departures from the model: rather than conditioning on the event that the observed data are generated by the model, one conditions on the event that the model generates data close to the observed data, in a distributional sense. When closeness is defined in terms of relative entropy, the resulting "coarsened" posterior can be approximated by simply tempering the likelihood-that is, by raising the likelihood to a fractional power-thus, inference can usually be implemented via standard algorithms, and one can even obtain analytical solutions when using conjugate priors. Some theoretical properties are derived, and we illustrate the approach with real and simulated data using mixture models and autoregressive models of unknown order.

16.
J Am Stat Assoc ; 113(521): 340-356, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29983475

RESUMEN

A natural Bayesian approach for mixture models with an unknown number of components is to take the usual finite mixture model with symmetric Dirichlet weights, and put a prior on the number of components-that is, to use a mixture of finite mixtures (MFM). The most commonly-used method of inference for MFMs is reversible jump Markov chain Monte Carlo, but it can be nontrivial to design good reversible jump moves, especially in high-dimensional spaces. Meanwhile, there are samplers for Dirichlet process mixture (DPM) models that are relatively simple and are easily adapted to new applications. It turns out that, in fact, many of the essential properties of DPMs are also exhibited by MFMs-an exchangeable partition distribution, restaurant process, random measure representation, and stick-breaking representation-and crucially, the MFM analogues are simple enough that they can be used much like the corresponding DPM properties. Consequently, many of the powerful methods developed for inference in DPMs can be directly applied to MFMs as well; this simplifies the implementation of MFMs and can substantially improve mixing. We illustrate with real and simulated data, including high-dimensional gene expression data used to discriminate cancer subtypes.

17.
Anesth Analg ; 126(6): 2009-2016, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29369091

RESUMEN

BACKGROUND: Acquisition of transthoracic echocardiographic (TTEcho) images in children often requires sedation. The optimal sedative for TTEcho has not been determined. Children with congenital heart disease are repeatedly exposed to sedatives and anesthetics that may affect brain development. Dexmedetomidine, which in animals alters brain structure to a lesser degree, may offer advantages in this vulnerable population. METHODS: A prospective, randomized, double-blind trial enrolled 280 children 3-24 months of age undergoing outpatient TTEcho, comparing 2.5 µg·kg intranasal dexmedetomidine to 5 mg·kg oral pentobarbital. Rescue sedation, for both groups, was intranasal dexmedetomidine 1 µg·kg. The primary outcome was adequate sedation within 30 minutes without rescue sedation, assessed by blinded personnel. Secondary outcomes included number of sonographer pauses, image quality in relation to motion artifacts, and parental satisfaction. RESULTS: Success rates with a single dose were not different between sedation techniques; 85% in the pentobarbital group and 84% in the dexmedetomidine group (P = .8697). Median onset of adequate sedation was marginally faster with pentobarbital (16.5 [interquartile range, 13-21] vs 18 [16-23] minutes for dexmedetomidine [P = .0095]). Time from drug administration to discharge was not different (P = .8238) at 70.5 (64-83) minutes with pentobarbital and 70 (63-82) minutes with dexmedetomidine. Ninety-five percent of sedation failures with pentobarbital and 100% of dexmedetomidine failures had successful rescue sedation with intranasal dexmedetomidine. CONCLUSIONS: Intranasal dexmedetomidine was comparable to oral pentobarbital sedation for TTEcho sedation in infants and did not increase the risk of clinically important adverse events. Intranasal dexmedetomidine appears to be an effective "rescue" sedative for both failed pentobarbital and dexmedetomidine sedation. Dexmedetomidine could be a safer option for repeated sedation in children, but further studies are needed to assess long-term consequence of repeated sedation in this high-risk population.


Asunto(s)
Dexmedetomidina/administración & dosificación , Ecocardiografía/efectos de los fármacos , Ecocardiografía/métodos , Hipnóticos y Sedantes/administración & dosificación , Pentobarbital/administración & dosificación , Administración Intranasal , Preescolar , Método Doble Ciego , Femenino , Cardiopatías Congénitas/diagnóstico por imagen , Cardiopatías Congénitas/cirugía , Humanos , Lactante , Masculino , Estudios Prospectivos
18.
J Neurointerv Surg ; 10(5): 446-450, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-28821627

RESUMEN

BACKGROUND AND PURPOSE: GEL THE NEC (GTN) was a multicenter prospective registry developed to assess the safety and efficacy of HydroSoft coils in treating intracranial aneurysms. We compared the angiographic and clinical outcomes of aneurysms treated with balloon assisted coil embolization (BACE) versus unassisted coil embolization (CE) in the ruptured aneurysm cohort. MATERIALS AND METHODS: GTN was performed at 27 centers in five countries. Patients aged 21-90 years with a ruptured aneurysm 3-15 mm in size were eligible for enrollment. We analyzed demographics/comorbidities, aneurysm location, and geometry, including maximum diameter, neck size, and dome to neck ratio, immediate and long term angiographic outcomes (graded by an independent core laboratory using the modified Raymond Scale), and procedure related adverse events. Angiographic and clinical outcomes were studied using χ2and t tests. RESULTS: Of the 599 patients in the GTN, 194 met the inclusion criteria. 84 were treated with BACE and 110 with CE. There were more prior smokers in the BACE group (p=0.01). The BACE group also had more vertebrobasilar aneurysms (p=0.006) and a larger mean neck size (p=0.02). More aneurysms were immediately completely occluded in the BACE group (p=0.02) Procedure- related major morbidity and mortality were no different between the techniques (p=0.4 and p=1, respectively). CONCLUSIONS: In this prospective ruptured aneurysm cohort from the GTN, BACE resulted in greater occlusion rates compared with unassisted CE with similar morbi-mortality.


Asunto(s)
Aneurisma Roto/diagnóstico por imagen , Aneurisma Roto/terapia , Oclusión con Balón/métodos , Angiografía Cerebral/métodos , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/terapia , Adulto , Anciano , Anciano de 80 o más Años , Prótesis Vascular , Estudios de Cohortes , Embolización Terapéutica/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sistema de Registros , Resultado del Tratamiento , Adulto Joven
19.
J Neurointerv Surg ; 10(1): 83-87, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28138062

RESUMEN

BACKGROUND AND PURPOSE: The HydroSoft coil was developed as a finishing coil, ideally to be placed along the aneurysm neck to enhance intracranial aneurysm healing. The GEL THE NEC (Gaining Efficacy Long Term: Hydrosoft, an Emerging, New, Embolic Coil) multicenter registry was developed to assess the safety and efficacy of HydroSoft coils in treating intracranial aneurysms. We report angiographic and clinical results of this prospective registry. MATERIALS AND METHODS: GEL THE NEC was performed at 27 centers in five countries. Patients aged 21-90 years with a ruptured or unruptured aneurysm 3-15 mm in size were eligible for enrollment. The following variables were obtained: demographics/comorbidities, aneurysm geometry, adjunctive devices used, proportion of patients in whom HydroSoft coils were successfully placed, and long-term angiographic outcomes (graded by an independent core laboratory using the Modified Raymond Scale), and procedure-related adverse events. Predictors of good angiographic outcome were studied using χ2 and t-tests. RESULTS: A total of 599 patients with 599 aneurysms were included in this study. HydroSoft coils were successfully deployed in 577 (96.4%) patients. Procedure-related major morbidity and mortality were 0.5% (3/599) and 1.3% (8/599), respectively. The most common perioperative complications were iatrogenic vasospasm (30/599, 5.0%), thromboemboli (27/599, 4.5%), and aneurysm perforation (16/599, 2.7%). At last angiographic follow-up (mean 9.0±6.3 months), the complete occlusion rate was 63.2% (280/442) and near complete occlusion rate was 25.2% (107/442). The core laboratory read recanalization rate was 10.8% (46/425) and the retreatment rate was 3.4% (20/599). CONCLUSIONS: Endovascular treatment of intracranial aneurysms with HydroSoft coils resulted in complete/near complete occlusion rates of 88% and a major complication rate of 1.8%. TRIAL REGISTRATION NUMBER: NCT01000675.


Asunto(s)
Embolización Terapéutica/normas , Procedimientos Endovasculares/normas , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/terapia , Complicaciones Posoperatorias/diagnóstico por imagen , Sistema de Registros , Adulto , Anciano , Anciano de 80 o más Años , Angiografía Cerebral/métodos , Embolización Terapéutica/efectos adversos , Embolización Terapéutica/métodos , Procedimientos Endovasculares/efectos adversos , Procedimientos Endovasculares/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Estudios Prospectivos , Resultado del Tratamiento
20.
World Neurosurg ; 108: 998.e7-998.e16, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28966151

RESUMEN

OBJECTIVES: Spinal dural arteriovenous fistulas (DAVFs) have diverse presentations. Magnetic resonance imaging (MRI) reveals spinal cord swelling in only 45% to 74% of cases. We present an unusual case of a 57-year old man with a craniocervical junction DAVF in which the edema appeared in the thoracolumbar region, skipping the cervical spinal cord. METHODS: A case report and literature review from a tertiary referral center are provided. RESULTS: In our patient, symptoms progressed over 3 months from low back and radicular pain to weakness, saddle anesthesia, and urinary retention. MRI showed T2 hyperintensity from T3-4 to the conus medullaris. The results from initial brain and spine angiograms were negative. Repeated angiography with the patient under anesthesia revealed a DAVF in the craniocervical junction composed of a cervical branch arising from the right vertebral artery and entering the nidus at the foramen magnum. A prominent intradural draining vein extended inferiorly along the posterior aspect of the cervical spinal cord. The patient was taken to the operating room, where the extradural vertebral artery was dissected and a suboccipital craniectomy was performed. After the dura was opened, the arterialized vein was visualized and clipped. Somatosensory evoked potentials and motor evoked potentials remained at baseline throughout the occlusion. The dura and fistula were removed en bloc, and the draining vein was confirmed to lose flow on indocyanine green. Postoperatively, the patient's symptoms completely resolved, and he experienced full strength in the lower extremities and perineal sensation. A review of 19 cases of DAVF at the craniocervical junction with cord edema shows that >90% involve the brainstem or cervical cord. Only 1 other patient had a similar "skip lesion," in which the cord edema first appeared in the thoracic cord. CONCLUSIONS: This rare presentation highlights the importance of diagnostic persistence when unexplained cord findings are seen on MRI. Repeated angiography and the inclusion of proximal vascular lesions may be considered in the evaluation of isolated thoracic edema.


Asunto(s)
Malformaciones Vasculares del Sistema Nervioso Central/diagnóstico por imagen , Atlas Cervical/cirugía , Enfermedades de la Médula Espinal/diagnóstico por imagen , Vértebras Torácicas , Angiografía , Articulación Atlantooccipital , Malformaciones Vasculares del Sistema Nervioso Central/complicaciones , Malformaciones Vasculares del Sistema Nervioso Central/cirugía , Angiografía Cerebral , Vértebras Cervicales , Craneotomía , Potenciales Evocados Motores , Potenciales Evocados Somatosensoriales , Foramen Magno , Humanos , Laminectomía , Dolor de la Región Lumbar/etiología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos , Radiculopatía/etiología , Enfermedades de la Médula Espinal/etiología , Enfermedades de la Médula Espinal/fisiopatología , Retención Urinaria/etiología , Arteria Vertebral
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