Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Cell ; 184(16): 4168-4185.e21, 2021 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-34216539

RESUMEN

Metabolism is a major regulator of immune cell function, but it remains difficult to study the metabolic status of individual cells. Here, we present Compass, an algorithm to characterize cellular metabolic states based on single-cell RNA sequencing and flux balance analysis. We applied Compass to associate metabolic states with T helper 17 (Th17) functional variability (pathogenic potential) and recovered a metabolic switch between glycolysis and fatty acid oxidation, akin to known Th17/regulatory T cell (Treg) differences, which we validated by metabolic assays. Compass also predicted that Th17 pathogenicity was associated with arginine and downstream polyamine metabolism. Indeed, polyamine-related enzyme expression was enhanced in pathogenic Th17 and suppressed in Treg cells. Chemical and genetic perturbation of polyamine metabolism inhibited Th17 cytokines, promoted Foxp3 expression, and remodeled the transcriptome and epigenome of Th17 cells toward a Treg-like state. In vivo perturbations of the polyamine pathway altered the phenotype of encephalitogenic T cells and attenuated tissue inflammation in CNS autoimmunity.


Asunto(s)
Autoinmunidad/inmunología , Modelos Biológicos , Células Th17/inmunología , Acetiltransferasas/metabolismo , Adenosina Trifosfato/metabolismo , Aerobiosis/efectos de los fármacos , Algoritmos , Animales , Autoinmunidad/efectos de los fármacos , Cromatina/metabolismo , Ciclo del Ácido Cítrico/efectos de los fármacos , Citocinas/metabolismo , Eflornitina/farmacología , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Epigenoma , Ácidos Grasos/metabolismo , Glucólisis/efectos de los fármacos , Histona Demetilasas con Dominio de Jumonji/metabolismo , Ratones Endogámicos C57BL , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Oxidación-Reducción/efectos de los fármacos , Putrescina/metabolismo , Análisis de la Célula Individual , Linfocitos T Reguladores/efectos de los fármacos , Linfocitos T Reguladores/inmunología , Células Th17/efectos de los fármacos , Transcriptoma/genética
2.
Curr Opin Ophthalmol ; 34(4): 354-360, 2023 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-37070535

RESUMEN

PURPOSE OF REVIEW: Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging technique, which provides depth resolved visualization of microvasculature of the retina and choroid. Although OCTA has been widely used for the evaluation of a number of retinal diseases, its use in the field of neuro-ophthalmology has been less studied. In this review, we provide an update on the utility of OCTA in neuro-ophthalmic conditions. RECENT FINDINGS: Peripapillary and macular microvasculature analyses have indicated that OCTA can be a promising tool for early detection of a number of neuro-ophthalmic diseases, differential diagnosis, and monitoring of disease progression. Recent studies have demonstrated that structural and functional impairment can develop at early stages in some conditions such as in multiple sclerosis and Alzheimer's disease even in the absence of overt clinical symptoms. Furthermore, this dye-less technique can be a valuable adjunct tool in the detection of complications commonly seen in some congenital entities such optic disc drusen. SUMMARY: Since its introduction, OCTA has emerged as an important imaging approach shedding light on unrevealed pathophysiological mechanisms of several ocular diseases. The use of OCTA as a biomarker in the field of neuro-ophthalmology has recently gained considerable attention with studies supporting its role in clinical setting while larger studies are warranted for correlating these findings with traditional diagnostic procedures and clinical features and outcomes.


Asunto(s)
Oftalmología , Enfermedades de la Retina , Humanos , Tomografía de Coherencia Óptica/métodos , Angiografía/métodos , Retina , Enfermedades de la Retina/diagnóstico por imagen , Angiografía con Fluoresceína/métodos , Vasos Retinianos
3.
J Neuroophthalmol ; 42(1): e430-e433, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-35475858

RESUMEN

ABSTRACT: A 55-year-old Caucasian man presented to the neuro-ophthalmology department for follow-up evaluation due to long-standing bilateral optic nerve head drusen (ONHD). On examination, the BCVA was 20/20-2 in both eyes. Dilated fundus examination revealed extensive ONHD in both eyes, retinal hemorrhages, exudates inferonasal to the macula, and macular edema inferotemporal to the disc margin. Automated visual field testing revealed generalized depression in both eyes. Late phase leakage was observed on fluorescein angiography (FA). Optical coherence tomography angiography identified a small juxtapapillary choroidal neovascular membrane inferonasal to the macula in the right eye correlating with the area of retinal hemorrhage and exudates.


Asunto(s)
Mácula Lútea , Drusas del Disco Óptico , Angiografía con Fluoresceína/métodos , Humanos , Masculino , Persona de Mediana Edad , Imagen Multimodal , Drusas del Disco Óptico/complicaciones , Drusas del Disco Óptico/diagnóstico , Hemorragia Retiniana , Tomografía de Coherencia Óptica/métodos
4.
Radiology ; 299(1): 234-236, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33750226

RESUMEN

History A 24-year-old right-handed woman presented to a neuro-ophthalmology clinic in Massachusetts in the summer with acute binocular diplopia when looking down and to the left, which started about 1 month earlier. Her medical history was notable for Raynaud syndrome, recurrent streptococcal pharyngitis, and an allergy to amoxicillin. Three days prior to developing diplopia, she presented to an outside emergency department due to fever, chills, and back pain. She received ciprofloxacin for presumed urinary tract infection based on urinalysis, which demonstrated few bacteria and was negative for leukocyte esterase, nitrites, and white blood cells. She then presented again to an outside emergency department for diplopia evaluation. Initial MRI and MR angiography of the brain at that time did not demonstrate any relevant findings, and the patient was referred to our department for neuro-ophthalmic evaluation, where she was seen 4 weeks later. Neuro-ophthalmic examination revealed 20/20 visual acuity in both eyes, and a right hypertropia in left gaze, downgaze and right head tilt, with right eye excyclotorsion. There were no ocular signs of myasthenia gravis or thyroid eye disease, nor did the patient report ocular or systemic symptoms. She denied recent travel. High-spatial-resolution MRI of the brain and orbit were performed (Figs 1, 2).

5.
Radiology ; 300(2): 484-488, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34310228

RESUMEN

History A 24-year-old right-handed woman presented to a neuro-ophthalmology clinic in Massachusetts in the summer with acute binocular diplopia when looking down and to the left, which started about 1 month earlier. Her medical history was notable for Raynaud syndrome, recurrent streptococcal pharyngitis, and an allergy to amoxicillin. Three days prior to developing diplopia, she presented to an outside emergency department due to fever, chills, and back pain. She received ciprofloxacin for presumed urinary tract infection based on urinalysis, which demonstrated few bacteria and was negative for leukocyte esterase, nitrites, and white blood cells. She then presented again to an outside emergency department for diplopia evaluation. Initial MRI and MR angiography of the brain at that time did not demonstrate any relevant findings, and the patient was referred to our department for neuro-ophthalmic evaluation, where she was seen 4 weeks later. Neuro-ophthalmic examination revealed 20/20 visual acuity in both eyes, and a right hypertropia in left gaze, downgaze and right head tilt, with right eye excyclotorsion. There were no ocular signs of myasthenia gravis or thyroid eye disease, nor did the patient report ocular or systemic symptoms. She denied recent travel. High-spatial-resolution MRI of the brain and orbit were performed.


Asunto(s)
Neuroborreliosis de Lyme/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Antibacterianos/uso terapéutico , Diagnóstico Diferencial , Doxiciclina/uso terapéutico , Femenino , Humanos , Neuroborreliosis de Lyme/tratamiento farmacológico , Adulto Joven
6.
Curr Opin Ophthalmol ; 32(6): 515-520, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34494975

RESUMEN

PURPOSE OF REVIEW: Dementia is a term for loss of memory, language, problem-solving, and other thinking abilities, which significantly interferes with daily life. Certain dementing conditions may also affect visual function. The eye is an accessible window to the brain that can provide valuable information for the early diagnosis of people who suffer from Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies as well as from more rare causes of dementias, such as Creutzfeldt-Jacob and Huntington's diseases. Herein, we present the ocular manifestations of neurocognitive disorders focusing on the neuro-ophthalmic ones and further discuss potential ocular biomarkers that could help in early detection of these disorders. RECENT FINDINGS: Ophthalmic examination along with the recent developments in in-vivo testing have provided a strong foundation of useful knowledge about brain disorder in neurodegenerative diseases without the need for invasive studies. Currently, a number of visual measures, such as visual acuity, contrast sensitivity, pupil response, and saccades in addition to various ophthalmic tests, such as electroretinogram, visual evoked potential, optical coherence tomography (OCT), and OCT-angiography have been widely used and evaluated as potential biomarkers for different stages of dementia. SUMMARY: Ophthalmologic and neuro-ophthalmic evaluation is evolving as an important part of the early diagnosis and management of people with dementia. A particular focus on ocular biomarkers in dementing illnesses has arisen over the past few years and there are several promising measures and imaging tools that have been proposed as potential biomarkers for these diseases.


Asunto(s)
Enfermedad de Alzheimer , Enfermedad de Huntington , Enfermedad de Parkinson , Encéfalo , Potenciales Evocados Visuales , Humanos
7.
Curr Opin Ophthalmol ; 31(6): 455-461, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33009076

RESUMEN

PURPOSE OF REVIEW: Optic nerve sheath meningiomas (ONSMs) are rare benign tumors of the anterior visual pathway which present with slowly progressive and painless vision loss and account for approximately 2% of all orbital tumors. This article provides an overview as well as an update on the ONSMs with regards to cause, epidemiology, clinical presentation, diagnosis, and management in adults and pediatric population. RECENT FINDINGS: The clinical presentation and prognosis of ONSMs can vary and largely depend on the location of tumor as well as the histologic type. Overall, the diagnosis is based on clinical presentation, examination, and neuroimaging findings. Nevertheless, delays in diagnosis or misdiagnosis are not uncommon and can result in higher morbidity rates. Recent advances in diagnostic as well as more effective and less-invasive treatment options are discussed in this review. SUMMARY: ONSMs are a rare cause of slowly progressive and inexorable visual loss. Although ONSM diagnosis depends on the characteristic clinical and radiologic findings, prompt diagnosis, and appropriate management is critical for favorable visual outcomes. Thus, current focus is optimizing diagnostic as well-treatment methods for patients with ONSMs.


Asunto(s)
Meningioma , Neoplasias del Nervio Óptico , Humanos , Meningioma/diagnóstico , Meningioma/terapia , Neuroimagen , Neoplasias del Nervio Óptico/diagnóstico , Neoplasias del Nervio Óptico/terapia , Pronóstico , Trastornos de la Visión/etiología
8.
Curr Opin Ophthalmol ; 30(6): 434-442, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31464700

RESUMEN

PURPOSE OF REVIEW: The phakomatoses are a group of inherited disorders with variable clinical manifestations that are characterized by brain, cutaneous, ocular and other distinct lesions in multiple organs. Correctly recognizing the neuro-ophthalmic signs and symptoms can lead to early diagnosis and treatment. The group is composed of neurofibromatosis (type 1 and 2), tuberous sclerosis complex, von Hippel-Lindau, ataxia-telangiectasia and Sturge-Weber syndromes. However, more than 60 syndromes have been described in the medical literature. This review provides an update on the diagnosis and management of phakomatoses with a focus on their clinical neuro-ophthalmic manifestations. RECENT FINDINGS: Phakomatoses are a group of inherited syndromes with variable clinical manifestations that are characterized by brain, cutaneous, ocular and other distinct lesions in multiple organs. Recent advances in diagnostic and treatment options that have contributed to prompt recognition and management of these disorders are discussed with an emphasis on the beneficial effects on vision. SUMMARY: Phakomatoses, also known as neuro-oculo-cutaneous syndromes, are inherited disorders with characteristic lesions in multiple organs. Because of their frequent ocular involvement thorough ophthalmologic and neuro-ophthalmic evaluation is critical in this patient population in order to prevent vision loss and life-threatening complications that are often associated with these disorders.


Asunto(s)
Oftalmopatías/diagnóstico , Síndromes Neurocutáneos/diagnóstico , Neurofibromatosis 1/diagnóstico , Esclerosis Tuberosa/diagnóstico , Humanos
9.
Curr Opin Ophthalmol ; 30(6): 426-433, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31449088

RESUMEN

PURPOSE OF REVIEW: Immune checkpoint inhibitors are currently an exceedingly powerful tool in the management of hitherto incurable malignancies and their use in clinical practice is expected to increase in the near future. The purpose of this review is to discuss the current medical uses of checkpoint inhibitors with a focus on their neuro-ophthalmic side-effects. RECENT FINDINGS: Immune checkpoint inhibitors have emerged as a promising breakthrough in the treatment of several tumor types. However, these targeted therapies can induce a wide range of immune-related ophthalmic and neuro-ophthalmic toxicities. It is important for neuro-ophthamologists to promptly recognize and manage these adverse events that can potentially threaten vision. SUMMARY: There are currently seven FDA-approved immune checkpoint inhibitors and several ones are under investigation. In general, immunotherapy is considered a well tolerated, safe and efficacious treatment option for many cancer patients. Nevertheless, because of their unique mechanism of action, these molecules can alter the immune response and result in immune-related adverse effects in almost every organ with an estimated incidence of ophthalmic side effects in this patient population of less than 1%.


Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antígeno B7-H1/antagonistas & inhibidores , Antígeno CTLA-4/antagonistas & inhibidores , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Infecciones del Ojo/tratamiento farmacológico , Neoplasias del Ojo/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Infecciones del Ojo/inmunología , Neoplasias del Ojo/inmunología , Humanos , Neurólogos , Oftalmólogos
15.
Psychiatry Res ; 331: 115629, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38029629

RESUMEN

A number of congenital and inherited diseases present with both ocular and psychiatric features. The genetic inheritance and phenotypic variants play a key role in disease severity. Early recognition of the signs and symptoms of those disorders is critical to earlier intervention and improved prognosis. Typically, the associations between these two medical subspecialties of ophthalmology and psychiatry are poorly understood by most practitioners so we hope to provide a narrative review to improve the identification and management of these disorders. We conducted a comprehensive review of the literature detailing the diseases with ophthalmic and psychiatric overlap that were more widely represented in the literature. Herein, we describe the clinical features, pathophysiology, molecular biology, diagnostic tests, and the most recent approaches for the treatment of these diseases. Recent studies have combined technologies for ocular and brain imaging such as optical coherence tomography (OCT) and functional imaging with genetic testing to identify the genetic basis for eye-brain connections. Additional work is needed to further explore these potential biomarkers. Overall, accurate, efficient, widely distributed and non-invasive tests that can help with early recognition of these diseases will improve the management of these patients using a multidisciplinary approach.


Asunto(s)
Oftalmología , Psiquiatría , Humanos , Pruebas Genéticas
16.
Ophthalmol Ther ; 13(6): 1417-1425, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38587773

RESUMEN

Transient monocular visual loss (TMVL), also known as transient monocular blindness or amaurosis fugax ("fleeting blindness"), is a temporary loss of vision often due to ischemia to the retina. While acute TMVL should be considered an emergency that further requires exhaustive investigation, there are some cases in which TMVL arises secondary to benign causes. Age has a major impact in the diagnosis of ischemia and although the differential diagnosis of TMVL can be broad, timely and appropriate history, examination, diagnostic testing, and treatment can be vision- or life-saving. We review the causes of TMVL and the impact of age on the differential diagnoses and management.

17.
Am J Ophthalmol ; 258: 208-216, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37726044

RESUMEN

PURPOSE: To investigate the demographic and clinical characteristics of patients with sympathetic ophthalmia (SO) and define the risk factors for its incidence following trauma and ophthalmic procedures. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients in the American Academy of Ophthalmology's (Academy) IRIS Registry (Intelligent Research in Sight) who were (n=1523) or were not diagnosed with SO following a documented procedure or trauma between January 1, 2013, and December 31, 2019. METHODS: Multiple demographic and clinical factors were collected, descriptive statistics and prevalence were calculated, and multivariate linear regression models were fit to the data. MAIN OUTCOME MEASURES: Prevalence of SO, demographic and clinical characteristics, and beta coefficient (ß) estimates of demographic and clinical characteristics impacting time to SO onset after procedure (Procedure Only cohort) or trauma (Trauma cohort). RESULTS: Of 65,348,409 distinct IRIS Registry patients, 1523 (0.0023%) were diagnosed with SO between 2013 and 2019, and also had a documented preceding trauma or procedure. Of these, 927 (60.87%) were female, 1336 (87.72%) belonged to the Procedure Only cohort, and 187 (12.28%) belonged to the Trauma cohort. The prevalence of SO after trauma was 0.0207%, whereas after procedures it was 0.0124%. The highest risk of procedure-related SO was seen in patients with history of "other anterior segment" (0.122%) followed by glaucoma (0.066%) procedures, whereas the lowest prevalence was noted with cataract surgeries (0.011%). The average time to onset of SO across both cohorts combined was 527.44 (±715.60) days, with statistically significant differences between the 2 cohorts (P < .001). On average, the time to onset from inciting event to SO was shorter with increasing age, by 9.02 (95% CI: -11.96, -6.08) days for every 1-year increase. CONCLUSIONS: SO following trauma and ophthalmic procedure is potentially rarer than previously reported, as measured in this large ophthalmic medical record database. Female sex may be a risk factor for SO. Older age may be a risk factor for quicker onset. These findings can guide clinical decision-making and management.


Asunto(s)
Glaucoma , Oftalmía Simpática , Humanos , Femenino , Estados Unidos/epidemiología , Recién Nacido , Masculino , Estudios Retrospectivos , Oftalmía Simpática/diagnóstico , Oftalmía Simpática/epidemiología , Glaucoma/complicaciones , Sistema de Registros , Factores de Riesgo
18.
Ocul Surf ; 32: 106-111, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38286216

RESUMEN

PURPOSE: Dry-eye disease (DED) is a chronic progressive ocular surface disorder with limited studies in the pediatric population. The Academy of Ophthalmology's IRIS® Registry was leveraged to investigate the prevalence of DED in the pediatric population (PDED, patients <18 years old) and the demographic differences of DED between pediatric and adult patients (ADED). METHODS: Retrospective cohort study. Patients with DED between January 1st, 2013 and December 31st, 2019 (N = 4,795,979) were included. Descriptive statistics, Pearson's chi-squared tests and two-sample proportions tests were conducted to compare key demographic distributions between the ADED and PDED cohorts. RESULTS: The average age at onset for ADED patients was 61.06 (±14.75) years and for PDED patients was 12.51 (±3.86). The overall tests for independence and the individual tests of proportions of each category were statistically significant for all demographic characteristics (p < 0.001). Characteristics with the largest discrepancies between patients of PDED and the IRIS Registry pediatric patient pool (PIRIS) included female sex (58.08 % vs. 50.60 %), male sex (41.58 % vs. 48.78 %) and Asian race (6.02 % vs. 3.11 %) respectively. Within the PDED cohort, females were at higher risk of PDED (58 % vs. 42 %). PDED was more prevalent in children with refractive errors (76 %) and eyelid/conjunctival disorders (41 %). Characteristics with the largest discrepancies between PDED and ADED patients included female sex (58.08 % vs. 68.12 %), male sex (41.58 % vs. 31.55 %) and Caucasian race (50.24 % vs. 67.06 %) respectively. CONCLUSIONS: Significant differences in the PDED cohort are demonstrated in this study. PDED was more prevalent in the female sex and Caucasian race compared to PIRIS and was more commonly associated with refractive errors and eyelid/conjunctival disorders.


Asunto(s)
Síndromes de Ojo Seco , Sistema de Registros , Humanos , Masculino , Estudios Retrospectivos , Femenino , Síndromes de Ojo Seco/epidemiología , Estados Unidos/epidemiología , Niño , Adolescente , Prevalencia , Persona de Mediana Edad , Adulto , Preescolar , Anciano , Adulto Joven , Distribución por Edad
19.
Ophthalmol Sci ; 4(1): 100357, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37869026

RESUMEN

Purpose: The most widely used classifications of age-related macular degeneration (AMD) and its severity stages still rely on color fundus photographs (CFPs). However, AMD has a wide phenotypic variability that remains poorly understood and is better characterized by OCT. We and others have shown that patients with AMD have a distinct plasma metabolomic profile compared with controls. However, all studies to date have been performed solely based on CFP classifications. This study aimed to assess if plasma metabolomic profiles are associated with OCT features commonly seen in AMD. Design: Prospectively designed, cross-sectional study. Participants: Subjects with a diagnosis of AMD and a control group (> 50 years old) from Boston, United States, and Coimbra, Portugal. Methods: All participants were imaged with CFP, used for AMD staging (Age-Related Eye Disease Study 2 classification scheme), and with spectral domain OCT (Spectralis, Heidelberg). OCT images were graded by 2 independent graders for the presence of characteristic AMD features, according to a predefined protocol. Fasting blood samples were collected for metabolomic profiling (using nontargeted high-resolution mass spectrometry by Metabolon Inc). Analyses were conducted using logistic regression models including the worst eye of each patient (AREDS2 classification) and adjusting for confounding factors. Each cohort (United States and Portugal) was analyzed separately and then results were combined by meta-analyses. False discovery rate (FDR) was used to account for multiple comparisons. Main Outcome Measures: Plasma metabolite levels associated with OCT features. Results: We included data on 468 patients, 374 with AMD and 94 controls, and on 725 named endogenous metabolites. Meta-analysis identified significant associations (FDR < 0.05) between plasma metabolites and 3 OCT features: hyperreflective foci (6), atrophy (6), and ellipsoid zone disruption (3). Most associations were seen with amino acids, and all but 1 metabolite presented specific associations with the OCT features assessed. Conclusions: To our knowledge, we show for the first time that plasma metabolites have associations with specific OCT features seen in AMD. Our results support that the wide spectrum of presentations of AMD likely include different pathophysiologic mechanisms by identifying specific pathways associated with each OCT feature. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

20.
J Clin Med ; 11(8)2022 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-35456174

RESUMEN

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in people over the age of 50 worldwide. Exudative or neovascular AMD is a more severe subset of AMD which is characterized by the presence of choroidal neovascularization (CNV). Recent advancements in multimodal ophthalmic imaging, including optical coherence tomography (OCT) and OCT-angiography (OCT-A), have facilitated the detection and characterization of previously undetectable neovascular lesions and have enabled a more refined classification of CNV in exudative as well as nonexudative AMD patients. Subthreshold exudative CNV is a novel subtype of exudative AMD that typically presents asymptomatically with good visual acuity and is characterized by stable persistent or intermittent subretinal fluid (SRF). This review aims to provide an overview of the clinical as well as multimodal imaging characteristics of CNV in AMD, including this new clinical phenotype, and propose effective approaches for management.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA