Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Am J Physiol Cell Physiol ; 326(5): C1494-C1504, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38406824

RESUMEN

Primary Sjögren's syndrome (pSS) is characterized by its autoimmune nature. This study investigates the role of the IFNγ SNP rs2069705 in modulating the susceptibility to pSS. Differential expression of IFNγ and BAFF was analyzed using the GEO database's mRNA microarray GSE84844. Genotyping of the IFNγ SNP rs2069705 was conducted via the dbSNP website. The JASPAR tool was used for predicting transcription factor bindings. Techniques such as dual-luciferase reporter assays, Chromatin immunoprecipitation, and analysis of a pSS mouse model were applied to study gene and protein interactions. A notable increase in the mutation frequency of IFNγ SNP rs2069705 was observed in MNCs from the exocrine glands of pSS mouse models. Bioinformatics analysis revealed elevated levels of IFNγ and BAFF in pSS samples. The model exhibited an increase in both CD20+ B cells and cells expressing IFNγ and BAFF. Knocking down IFNγ resulted in lowered BAFF expression and less lymphocyte infiltration, with BAFF overexpression reversing this suppression. Activation of the Janus kinase (JAK)/STAT1 pathway was found to enhance transcription in the BAFF promoter region, highlighting IFNγ's involvement in pSS. In addition, rs2069705 was shown to boost IFNγ transcription by promoting interaction between its promoter and STAT4. SNP rs2069705 in the IFNγ gene emerges as a pivotal element in pSS susceptibility, primarily by augmenting IFNγ transcription, activating the JAK/STAT1 pathway, and leading to B-lymphocyte infiltration in the exocrine glands.NEW & NOTEWORTHY The research employed a combination of bioinformatics analysis, genotyping, and experimental models, providing a multifaceted approach to understanding the complex interactions in pSS. We have uncovered that the rs2069705 SNP significantly affects the transcription of IFNγ, leading to altered immune responses and B-lymphocyte activity in pSS.


Asunto(s)
Linfocitos B , Interferón gamma , Polimorfismo de Nucleótido Simple , Síndrome de Sjögren , Activación Transcripcional , Animales , Femenino , Humanos , Ratones , Factor Activador de Células B/genética , Factor Activador de Células B/metabolismo , Linfocitos B/inmunología , Linfocitos B/metabolismo , Modelos Animales de Enfermedad , Predisposición Genética a la Enfermedad , Interferón gamma/genética , Interferón gamma/metabolismo , Quinasas Janus/metabolismo , Quinasas Janus/genética , Polimorfismo de Nucleótido Simple/genética , Transducción de Señal , Síndrome de Sjögren/genética , Síndrome de Sjögren/inmunología , Síndrome de Sjögren/metabolismo , Síndrome de Sjögren/patología , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT4/genética , Factor de Transcripción STAT4/metabolismo
2.
Hum Brain Mapp ; 44(1): 142-155, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36005850

RESUMEN

The neural mechanisms that support handwriting, an important mode of human communication, are thought to be controlled by a central process (responsible for spelling) and a peripheral process (responsible for motor output). However, the relationship between central and peripheral processes has been debated. Using functional magnetic resonance imaging, this study examined the neural mechanisms underlying this relationship in Chinese handwriting in 36 children (mean age = 10.40 years) and 56 adults (mean age = 22.36 years) by manipulating character frequency (a central variable). Brain network analysis showed that character frequency reconfigured functional brain networks known to underlie motor processes, including the somatomotor and cerebellar network, in both children and adults, indicating that central processing cascades into peripheral processing. Furthermore, the network analysis characterized the interaction profiles between motor networks and linguistic-cognitive networks, fully mapping the neural architecture that supports the interaction of central and peripheral processes involved in handwriting. Taken together, these results reveal the neural interface underlying the interaction between central and peripheral processes involved in handwriting in a logographic writing system, advancing our understanding of the neural basis of handwriting.


Asunto(s)
Encéfalo , Pueblos del Este de Asia , Humanos , Adulto , Niño , Adulto Joven , Encéfalo/diagnóstico por imagen , Escritura Manual , Mapeo Encefálico , Lenguaje
3.
Dev Sci ; 25(2): e13161, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34288292

RESUMEN

Abundant behavioral studies have demonstrated high comorbidity of reading and handwriting difficulties in developmental dyslexia (DD), a neurological condition characterized by unexpectedly low reading ability despite adequate nonverbal intelligence and typical schooling. The neural correlates of handwriting deficits remain largely unknown; however, as well as the extent that handwriting deficits share common neural bases with reading deficits in DD. The present work used functional magnetic resonance imaging to examine brain activity during handwriting and reading tasks in Chinese dyslexic children (n = 18) and age-matched controls (n = 23). Compared to controls, dyslexic children exhibited reduced activation during handwriting tasks in brain regions supporting sensory-motor processing (including supplementary motor area and postcentral gyrus) and visual-orthography processing (including bilateral precuneus and right cuneus). Among these regions, the left supplementary motor area and the right precuneus also showed a trend of reduced activation during reading tasks in dyslexics. Moreover, increased activation was found in the left inferior frontal gyrus and anterior cingulate cortex in dyslexics, which may reflect more efforts of executive control to compensate for the impairments of motor and visual-orthographic processing. Finally, dyslexic children exhibited aberrant functional connectivity among brain areas for cognitive control and sensory-motor processes during handwriting tasks. Together, these findings suggest that handwriting deficits in DD are associated with functional abnormalities of multiple brain regions implicated in motor execution, visual-orthographic processing, and cognitive control, providing important implications for the diagnosis and treatment of dyslexia.


Asunto(s)
Dislexia , Encéfalo , Mapeo Encefálico , Niño , China , Escritura Manual , Humanos , Imagen por Resonancia Magnética/métodos , Lectura
4.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 48(1): 75-82, 2019 05 25.
Artículo en Zh | MEDLINE | ID: mdl-31102361

RESUMEN

OBJECTIVE: To investigate the developmental characteristics of resilience in children aged 3-5, and to explore the relationship between temperament, parenting style and resilience. METHODS: A total of 570 preschoolers aged 3-5 years in Hangzhou participated in this study. The children's teachers completed the assessment of the resilience scale of DECA-P2 (Devereux Early Childhood Assessment for Preschoolers Second Edition); the children's parents completed assessment of temperament questionnaire CBQ (Children's Behavior Questionnaire) and parenting style questionnaire PSDQ (Parenting Styles and Dimensions Questionnaire). RESULTS: Totally 432 valid questionnaires were retrieved with a recovery rate of 75.79%. The levels of initiative and self-regulation of 5-y children were higher than those of children aged 3 or 4 (all P<0.01); the level of attachment/relationship of 5-y children was higher than that of children aged 4 (P<0.01); the levels of initiative and self-regulation of girls were higher than those of boys (P<0.05 or P<0.01). The negative affect dimension of temperament was negatively correlated with resilience (all P<0.05), while the effortful control and authoritative parenting styles were positively correlated with resilience (all P<0.05). The negative affect and effortful control were able to partially predict resilience of children through authoritative parenting style (mediating effect were-0.0143 and 0.0363). CONCLUSIONS: Preschoolers aged 3-5 years with different age and gender show differences in resilience, and parenting styles may play a mediating effect between temperament and resilience.


Asunto(s)
Responsabilidad Parental , Resiliencia Psicológica , Temperamento , Niño , Conducta Infantil , Preescolar , Femenino , Humanos , Masculino , Factores Sexuales , Encuestas y Cuestionarios
5.
ScientificWorldJournal ; 2014: 647216, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25032231

RESUMEN

In recent years, many approaches have been suggested for Internet and web streaming detection. In this paper, we propose an approach to signal waveform detection for Internet and web streaming, with novel statistical automatons. The system records network connections over a period of time to form a signal waveform and compute suspicious characteristics of the waveform. Network streaming according to these selected waveform features by our newly designed Aho-Corasick (AC) automatons can be classified. We developed two versions, that is, basic AC and advanced AC-histogram waveform automata, and conducted comprehensive experimentation. The results confirm that our approach is feasible and suitable for deployment.


Asunto(s)
Algoritmos , Internet , Difusión por la Web como Asunto
6.
J Learn Disabil ; : 222194241241040, 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38591175

RESUMEN

A growing body of evidence suggests that children with dyslexia in alphabetic languages exhibit visual-spatial attention deficits that can obstruct reading acquisition by impairing their phonological decoding skills. However, it remains an open question whether these visual-spatial attention deficits are present in children with dyslexia in non-alphabetic languages. Chinese, with its logographic writing system, offers a unique opportunity to explore this question. The presence of visual-spatial attention deficits in Chinese children with dyslexia remains insufficiently investigated. Therefore, this study aimed to explore whether such deficits exist, employing a visual search paradigm. Three visual search tasks were conducted, encompassing two singleton feature search tasks and a serial conjunction search task. The results indicated that Chinese children with dyslexia performed as well as chronological age-matched control children in color search tasks but less effectively in orientation search, suggesting a difficulty in the rapid visual processing of orientation: a deficit potentially specific to Chinese dyslexia. Crucially, Chinese children with dyslexia also exhibited lower accuracy, longer reaction times, and steeper slopes in the reaction times by set size function in the conjunction search task compared to control children, which is indicative of a visual-spatial attention deficit.

7.
Front Oncol ; 14: 1392540, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39175476

RESUMEN

Solitary fibrous tumor (SFT) is a type of fibroblastic neoplasm that can occur in various parts of the body, with SFT of the pineal gland being exceedingly rare. We report the case of a 58-year-old male presenting with recurrent hiccups, acid reflux, and headache. Magnetic resonance imaging revealed an occupying lesion in the pineal region, suggestive of a neoplastic process. Intraoperatively, the lesion was located in the pineal region, exhibiting a grayish-red color, and was largely resected. Pathological examination confirmed the diagnosis of solitary fibrous tumor (CNS WHO Grade 1). Postoperatively, the patient was supplemented with radiotherapy, and long-term follow-up showed no signs of recurrence or metastasis.

8.
Front Oncol ; 13: 1182261, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37434973

RESUMEN

Background: Choroid plexus papilloma (CPP) is rare and even rarer in infants and young children, and it usually occurs in the ventricles. Due to the physical peculiarities of infants, tumor removal by microscopic or endoscopic surgery alone is difficult. Case Presentation: A 3-month-old patient was found to have an abnormally enlarged head circumference for 7 days. Cranial magnetic resonance imaging (MRI) examination revealed a lesion in the third ventricle. The patient underwent combined microscopic and endoscopic "chopstick" technique to remove the tumor. He recovered well after the surgery. Postoperative pathological examination revealed CPP. Postoperative MRI suggested total resection of the tumor. Follow-up for 1 month showed no recurrence or distant metastasis. Conclusions: Combined microscopic and endoscopic "chopstick" technique may be a suitable approach to remove tumors in infant ventricles.

9.
Health Inf Sci Syst ; 11(1): 9, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36721638

RESUMEN

3D medical image segmentation has an essential role in medical image analysis, while attention mechanism has improved the performance by a large margin. However, existing methods obtained the attention coefficient in a small receptive field, resulting in possible performance limitations. Radiologists usually scan all the slices first to have an overall idea of the target, and then analyze regions of interest in multiple 2D views in clinic practice. We simulate radiologists' recognition process and propose to exploit the 3D context information in a deeper manner for accurate 3D medical images segmentation. Due to the similarity of human body structure, medical images of different populations have highly similar shape and location information, so we use target region distillation to extract the common segmented region information. Particularly, we proposed two optimizations including Target Area Distillation and Section Attention. Target Area Distillation adds positions information to the original input to let the network has an initial attention of the target, while section attention performs attention extraction in three 2D sections thus with large range of receptive field. We compare our method against several popular networks in two public datasets including ImageCHD and COVID-19. Experimental results show that our proposed method improves the segmentation Dice score by 2-4% over the state-of-the-art methods. Our code has been released to the public (Anonymous link).

10.
Radiol Case Rep ; 17(7): 2408-2415, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35570878

RESUMEN

Fetus in fetu (FIF) is a rare congenital disease caused by the abnormal development of monochorionic diamniotic twins that appears as a cystic mass containing fetus-like structures mainly in the retroperitoneum of infants. The clinical manifestations of fetus in fetu vary, but they mostly present at infancy, hence, it should be differentiated from a teratoma. Here, we report a case of an infant with fetus in fetu in the retroperitoneum. Enhanced computed tomography scans and three-dimensional images showed a huge mixed-density mass on the left side of the abdominopelvic cavity with patchy distribution of fat, intact bones, and soft tissue. The child underwent fetus in fetu resection under general anaesthesia. Histopathology confirmed that the mass contained skin, muscle, intestinal mucosa, bones and cartilage, nerves, muscles, fat, and bone marrow tissue.

11.
World J Gastrointest Oncol ; 14(12): 2313-2328, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36568939

RESUMEN

BACKGROUND: Invasion and migration are the irreversible stages of colorectal cancer (CRC). The key is to find a sensitive, reliable molecular marker that can predict the migration of CRC at an early stage. N-myc downstream regulated gene 1 (NDRG1) is a multifunctional gene that has been tentatively reported to have a strong relationship with tumor invasion and migration, however the current molecular role of NDRG1 in CRC remains unknown. AIM: To explore the role of NDRG1 in the development of CRC. METHODS: NDRG1 stably over-expressed Caco2 cell line was established by lentiviral infection and NDRG1 knock-out Caco2 cell line was established by CRISPR/Cas9. Furthermore, the mRNA and protein levels of NDRG1 in Caco2 cells after NDRG1 over-expression and knockout were detected by real-time polymerase chain reaction and western blot. The cell proliferation rate was measured by the cell counting kit-8 method; cell cycle and apoptosis were detected by flow cytometry; invasion and migration ability were detected by the 24-transwell method. RESULTS: NDRG1 over-expression inhibited Caco2 proliferation and the cell cycle could be arrested at the G1/S phase when NDRG1 was over-expressed, while the number of cells in the G2 phase was significantly increased when NDRG1 was knocked out. This suggests that NDRG1 inhibited the proliferation of Caco2 cells by arresting the cell cycle in the G1/S phase. Our data also demonstrated that NDRG1 promotes early cell apoptosis. Invasion and migration of cells were extensively inhibited when NDRG1 was over-expressed. CONCLUSION: NDRG1 inhibits tumor progression in Caco2 cells which may represent a potential novel therapeutic strategy for the treatment of CRC.

12.
World J Clin Cases ; 10(24): 8634-8640, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-36157825

RESUMEN

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare, non-genetic disorder characterized by multiple gastrointestinal polyps, and ectodermal lesions such as alopecia, fingernail atrophy, and skin mucosal pigmentation. Unfortunately, the pathogenesis of CCS is currently unknown. CASE SUMMARY: Here, we describe the case of an elderly female with diarrhea, fatigue, and hair loss, who experienced abdominal pain for over half a year and was found to have multiple gastrointestinal polyps. She was diagnosed with CCS and was treated with albumin supplementation and prednisone, and her electrolyte imbalance was corrected. Following treatment, her symptoms significantly improved. To elucidate the role of potential genetic events in the pathogenesis of CCS, we performed exome sequencing using an extract of her colorectal adenoma. CONCLUSION: Our data revealed multiple somatic mutations and copy number variations. Our findings provide a novel insight into the potential mechanisms of CCS etiology.

13.
Front Endocrinol (Lausanne) ; 13: 856268, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35370936

RESUMEN

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. In the elderly (≥70 years old) primary operable (T1-3N0-1M0) TNBC, individualized treatment modalities for this population are pivotal and important, but limited studies are explored. Methods: The clinicopathological features of elderly primary operable TNBC patients were retrospectively selected from the Surveillance, Epidemiology, and End Results (SEER) database between January 2010 and December 2015. Kaplan-Meier curves were used to show the survival patterns in the different subgroups. Multivariate Cox analysis was used to identify independent risk factors in the 3-, 5-, and 7- year overall survival (OS) and cancer-specific survival (CSS) in this subpopulation. The predictive model was further developed and validated for clinical use. Result: Between 2010 and 2015 years, a total of 4,761 elderly primary operable TNBC patients were enrolled for the study, with a mean age of 76 years and a median follow-up of 56 months. The multivariate Cox analysis showed that age (increased per year: hazard ratio (HR) = 1.05), race (Asian/Pacific Islander and American Indian/Alaska Native, HR = 0.73), differentiation grade (grade II: HR = 2.01; grade III/IV: HR = 2.67), larger tumor size (T1c: HR = 1.83; T2: HR = 2.78; T3: HR = 4.93), positive N stage (N1mi: HR = 1.60; N1: HR = 1.54), receiving radiation therapy (HR = 0.66), and receiving adjuvant chemotherapy (HR = 0.61) were the independent prognostic factors for OS, and a similar prognostic pattern was also determined in CSS. Besides, two nomograms for predicting the 3-, 5-, and 7-year OS and CSS in this population were developed with a favorable concordance index of 0.716 and 0.746, respectively. Conclusion: The results highlight that both radiation and adjuvant chemotherapy are significantly associated with favorable long-term OS and CSS probability in elderly primary operable TNBC patients. Based on the determined independent prognostic factors, the novel nomograms could assist the oncologists to make individualized clinical decisions for the subpopulation at different risks.


Asunto(s)
Neoplasias de la Mama Triple Negativas , Anciano , Humanos , Nomogramas , Pronóstico , Estudios Retrospectivos , Programa de VERF , Neoplasias de la Mama Triple Negativas/epidemiología , Neoplasias de la Mama Triple Negativas/cirugía
14.
Technol Cancer Res Treat ; 20: 15330338211039678, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34482774

RESUMEN

The incidence of colorectal cancer (CRC), as well as subsequent patient mortality, has increased in the last decade; an unhealthy diet is considered to be the leading cause. Previous studies have shown the potential of the bromodomain containing 1 (BRD1) gene as a therapeutic target for CRC based on its specificity; however, the genetic mode of action and expression in CRC cells are yet to be investigated. In this study, target genes were screened from single-cell transcriptome sequencing data, and the collected clinical specimens were subjected to immunohistochemistry (IHC) to identify the protein expression of target genes; the results were verified in the GSE17536 array set. Receiver operating characteristic curves (ROC) and overall survival (OS) were used to test target genes as biomarkers and independent predictive markers for CRC. Based on these results, BRD1 was screened as a target gene, and IHC results showed that BRD1 protein expression in CRC was higher than that in normal tissues and was significantly upregulated in poorly differentiated (PD) CRC. ROC analysis showed that the area under the curve in the collected clinical specimens and GSE17536 were 0.6062 and 0.6094, respectively. OS analysis showed that higher BRD1 protein expression was associated with a significantly shorter survival time. In conclusion, BRD1 expression was positively correlated with PD CRC and negatively correlated with OS, indicating that BRD1 could predict the differentiation state of CRC and may be a novel predictive biomarker.


Asunto(s)
Biomarcadores de Tumor , Neoplasias Colorrectales/genética , Regulación Neoplásica de la Expresión Génica , Histona Acetiltransferasas/genética , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Biología Computacional/métodos , Bases de Datos Genéticas , Perfilación de la Expresión Génica , Histona Acetiltransferasas/metabolismo , Humanos , Anotación de Secuencia Molecular , Pronóstico , RNA-Seq
15.
IEEE Trans Neural Netw Learn Syst ; 32(6): 2676-2690, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32692684

RESUMEN

Recent works on video salient object detection have demonstrated that directly transferring the generalization ability of image-based models to video data without modeling spatial-temporal information remains nontrivial and challenging. Considering both intraframe accuracy and interframe consistency of saliency detection, this article presents a novel cross-attention based encoder-decoder model under the Siamese framework (CASNet) for video salient object detection. A baseline encoder-decoder model trained with Lovász softmax loss function is adopted as a backbone network to guarantee the accuracy of intraframe salient object detection. Self- and cross-attention modules are incorporated into our model in order to preserve the saliency correlation and improve intraframe salient detection consistency. Extensive experimental results obtained by ablation analysis and cross-data set validation demonstrate the effectiveness of our proposed method. Quantitative results indicate that our CASNet model outperforms 19 state-of-the-art image- and video-based methods on six benchmark data sets.

16.
Front Psychol ; 11: 958, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32581906

RESUMEN

Many studies have suggested that children with developmental dyslexia (DD) not only show phonological deficit but also have difficulties in visual processing, especially in non-alphabetic languages such as Chinese. However, mechanisms underlying this impairment in vision are still unclear. Visual magnocellular deficit theory suggests that the difficulties in the visual processing of dyslexia are caused by the dysfunction of the magnocellular system. However, some researchers have pointed out that previous studies supporting the magnocellular theory did not control for the role of "noise". The visual processing difficulties of dyslexia might be related to the noise exclusion deficit. The present study aims to examine these two possible explanations via two experiments. In experiment 1, we recruited 26 Chinese children with DD and 26 chronological age-matched controls (CA) from grades 3 to 5. We compared the Gabor contrast sensitivity between the two groups in high-noise and low-noise conditions. Results showed a significant between-group difference in contrast sensitivity in only the high-noise condition. In experiment 2, we recruited another 29 DD and 29 CA and compared the coherent motion/form sensitivity in the high- and low-noise conditions. Results also showed that DD exhibited lower coherent motion and form sensitivities than CA in the high-noise condition, whereas no evidence was observed that the group difference was significant in the low-noise condition. These results suggest that Chinese children with dyslexia have noise exclusion deficit, supporting the noise exclusion hypothesis. The present study provides evidence for revealing the visual dysfunction of dyslexia from the Chinese perspective. The nature of the perceptual noise exclusion and the relationship between the two theoretical hypotheses are discussed.

17.
Int J Clin Exp Pathol ; 10(9): 9889-9893, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-31966877

RESUMEN

BACKGROUND: Although the occurrence of primary extragonadal seminoma is rare, there are reported clinical cases of seminoma occurring in mediastinum, lung, retroperitoneal, central nervous system, and even in the small intestine. However, there is lack of report of rectal seminoma. Here we report a case of rectal seminoma in a 53 years old Chinese patient. CASE DESCRIPTION: This 53-year-old male patient presented with bulging anus and abnormality in the shape of his stool. Physical examination revealed that the patient's external genital organs have abnormal development, presenting characters of disorder of sex development, which was absence of testis in scrotum. Computed tomography (CT) scan of abdomen and pelvic cavity found that there was a tumor of irregular shape in the lower rectum. In addition, there was no other tumor found in the other parts of the body. Results from immunohistochemistry showed that placental alkaline phosphatase (PLAP) and CD117 were positive. Based on the examination results described above, this clinical case was diagnosed as seminoma. CONCLUSION: Due to the rareness of rectal seminoma in patients of disorder of sex development, diagnosis should be made with extra cautious by taking into account of clinical symptoms, images of tomography scan, pathology test and immunohistochemical analysis. When seminoma occurs in extragonadal, it needs to be examined with extra care to exclude the possibility of other types of tumor. Further research is required to evaluate whether there is any association between disorder of sex development and extragonadal seminoma.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA