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1.
Mol Hum Reprod ; 30(6)2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38745364

RESUMEN

The role of cumulus cells (CCs) in the acquisition of oocyte developmental competence is not yet fully understood. In a previous study, we matured cumulus-denuded fully-grown mouse oocytes to metaphase II (MII) on a feeder layer of CCs (FL-CCs) isolated from developmentally competent (FL-SN-CCs) or incompetent (FL-NSN-CCs) SN (surrounded nucleolus) or NSN (not surrounding nucleolus) oocytes, respectively. We observed that oocytes cultured on the former could develop into blastocysts, while those matured on the latter arrested at the 2-cell stage. To investigate the CC factors contributing to oocyte developmental competence, here we focused on the CCs' release into the medium of extracellular vesicles (EVs) and on their miRNA content. We found that, during the 15-h transition to MII, both FL-SN-CCs and FL-NSN-CCs release EVs that can be detected, by confocal microscopy, inside the zona pellucida (ZP) or the ooplasm. The majority of EVs are <200 nm in size, which is compatible with their ability to cross the ZP. Next-generation sequencing of the miRNome of FL-SN-CC versus FL-NSN-CC EVs highlighted 74 differentially expressed miRNAs, with 43 up- and 31 down-regulated. Although most of these miRNAs do not have known roles in the ovary, in silico functional analysis showed that seven of these miRNAs regulate 71 target genes with specific roles in meiosis resumption (N = 24), follicle growth (N = 23), fertilization (N = 1), and the acquisition of oocyte developmental competence (N = 23). Overall, our results indicate CC EVs as emerging candidates of the CC-to-oocyte communication axis and uncover a group of miRNAs as potential regulatory factors.


Asunto(s)
Células del Cúmulo , Vesículas Extracelulares , MicroARNs , Oocitos , Animales , Células del Cúmulo/metabolismo , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/genética , Oocitos/metabolismo , MicroARNs/metabolismo , MicroARNs/genética , Ratones , Femenino , Técnicas de Maduración In Vitro de los Oocitos , Oogénesis/genética , Zona Pelúcida/metabolismo
2.
Artículo en Inglés | MEDLINE | ID: mdl-38717884

RESUMEN

One-class support vector machine (SVM) is an extension of SVM to handle unlabeled data. As a mature technique for outlier detection, one-class SVM has been widely used in many applications. However, similar to standard two-class SVM, the design of one-class SVM does not give probabilistic outputs. For two-class SVM, some methods have been proposed to effectively obtain probabilistic outputs, but due to the difficulty of no-label information, less attention has been paid to one-class SVM. Our aim in this work is to propose some practically viable techniques to generate probabilistic outputs for one-class SVM. We investigate existing methods for two-class SVM and explain why they may not be suitable for one-class SVM. Due to the lack of label information, we think a feasible setting is to have probabilities mimic to the decision values of training data. Based on this principle, we propose several new methods. Detailed experiments on both artificial and real-world data demonstrate the effectiveness of the proposed methods.

3.
Fac Rev ; 12: 26, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37920274

RESUMEN

Ectopic pregnancy (EP) is described as the implantation of an embryo outside the normal uterine cavity. It most commonly occurs in the fallopian tube, hence termed a tubal ectopic pregnancy (tEP). It is a gynaecological emergency and remains the leading cause of direct maternal mortality related to the first trimester of pregnancy worldwide. This article explores the emergence of additional risk factors for tEP, showing new evidence for identifying patient risk factors and highlighting potential areas of research. Additionally, we discuss the up-to-date patient-centred approach for the diagnosis, management and counselling of patients with tEP and ongoing clinical trials for the improvement of medical management.

4.
Commun Biol ; 6(1): 543, 2023 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-37202417

RESUMEN

The role of the mechanical environment in defining tissue function, development and growth has been shown to be fundamental. Assessment of the changes in stiffness of tissue matrices at multiple scales has relied mostly on invasive and often specialist equipment such as AFM or mechanical testing devices poorly suited to the cell culture workflow.In this paper, we have developed a unbiased passive optical coherence elastography method, exploiting ambient vibrations in the sample that enables real-time noninvasive quantitative profiling of cells and tissues. We demonstrate a robust method that decouples optical scattering and mechanical properties by actively compensating for scattering associated noise bias and reducing variance. The efficiency for the method to retrieve ground truth is validated in silico and in vitro, and exemplified for key applications such as time course mechanical profiling of bone and cartilage spheroids, tissue engineering cancer models, tissue repair models and single cell. Our method is readily implementable with any commercial optical coherence tomography system without any hardware modifications, and thus offers a breakthrough in on-line tissue mechanical assessment of spatial mechanical properties for organoids, soft tissues and tissue engineering.


Asunto(s)
Diagnóstico por Imagen de Elasticidad , Vibración , Diagnóstico por Imagen de Elasticidad/métodos , Tomografía de Coherencia Óptica/métodos , Cartílago , Organoides
5.
J Funct Biomater ; 13(3)2022 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-36135568

RESUMEN

Although laser irradiation and implantoplasty (IP) are both treatment options for peri-implantitis, no studies have yet combined these two treatment solutions. The aim of this study was to identify the effect of an Er, Cr: YSGG laser on the IP surface. In experiment 1, TiUnite anodized surface implants were treated with an Er, Cr: YSGG laser at 0.5 to 2 W on the panel energy setting and 20 Hz under water irrigation. In experiment 2, all implant surfaces were treated with the IP procedure first, then irradiated with the Er, Cr: YSGG laser. All samples were analyzed by stereomicroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and surface topography. Stereomicroscopy and SEM revealed no obvious surface change at any energy setting once the surface was polished with the IP procedure, whereas damage was caused to the TiUnite original implant surface when the Er, Cr: YSGG laser panel energy was set at 1 W or higher. EDS showed no significant difference in element composition once the surface was polished with the IP procedure, while a compositional change was detected when the Er, Cr: YSGG laser panel energy was set to 0.5 W or higher to irradiate the original TiUnite surface. Surface roughness may be related to laser irradiation energy, but no significant changes occurred following IP. These results indicated that the Er, Cr: YSGG laser may have little effect on the post-IP surface compared with the virgin TiUnite surface.

6.
Development ; 149(5)2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-35112132

RESUMEN

Successful reproduction requires an oocyte competent to sustain early embryo development. By the end of oogenesis, the oocyte has entered a transcriptionally silenced state, the mechanisms and significance of which remain poorly understood. Histone H3.3, a histone H3 variant, has unique cell cycle-independent functions in chromatin structure and gene expression. Here, we have characterised the H3.3 chaperone Hira/Cabin1/Ubn1 complex, showing that loss of function of any of these subunits causes early embryogenesis failure in mouse. Transcriptome and nascent RNA analyses revealed that transcription is aberrantly silenced in mutant oocytes. Histone marks, including H3K4me3 and H3K9me3, are reduced and chromatin accessibility is impaired in Hira/Cabin1 mutants. Misregulated genes in mutant oocytes include Zscan4d, a two-cell specific gene involved in zygote genome activation. Overexpression of Zscan4 in the oocyte partially recapitulates the phenotypes of Hira mutants and Zscan4 knockdown in Cabin1 mutant oocytes partially restored their developmental potential, illustrating that temporal and spatial expression of Zscan4 is fine-tuned at the oocyte-to-embryo transition. Thus, the H3.3 chaperone Hira complex has a maternal effect function in oocyte developmental competence and embryogenesis, through modulating chromatin condensation and transcriptional quiescence.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Chaperonas de Histonas/metabolismo , Histonas/metabolismo , Oocitos/crecimiento & desarrollo , Oocitos/metabolismo , Transducción de Señal/genética , Factores de Transcripción/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Proteínas de Ciclo Celular/genética , Cromatina/metabolismo , Desarrollo Embrionario/genética , Femenino , Técnicas de Silenciamiento del Gen , Chaperonas de Histonas/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Oogénesis/genética , Factores de Transcripción/genética , Cigoto/metabolismo
7.
IEEE Trans Neural Netw Learn Syst ; 33(7): 2828-2841, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33428576

RESUMEN

Truncated Newton (TN) methods have been a useful technique for large-scale optimization. Instead of obtaining the full Newton direction, a truncated method approximately solves the Newton equation with an inner conjugate gradient (CG) procedure (TNCG for the whole method). These methods have been employed to efficiently solve linear classification problems. However, even in this deeply studied field, various theoretical and numerical aspects were not completely explored. The first contribution of this work is to comprehensively study the global and local convergence when TNCG is applied to linear classification. Because of the lack of twice differentiability under some losses, many past works cannot be applied here. We prove various missing pieces of theory from scratch and clarify many proper references. The second contribution is to study the termination of the CG method. For the first time when TNCG is applied to linear classification, we show that the inner stopping condition strongly affects the convergence speed. We propose using a quadratic stopping criterion to achieve both robustness and efficiency. The third contribution is that of combining the study on inner stopping criteria with that of preconditioning. We discuss how convergence theory is affected by preconditioning and finally propose an effective preconditioned TNCG.

8.
STAR Protoc ; 2(3): 100726, 2021 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-34409306

RESUMEN

LINE1 is the most active and abundant family of retrotransposons; it is implicated in a number of pathologies, as well as in early embryo development. We present a protocol to specifically knockdown LINE1 in mouse embryonic stem cells and embryos, including details for the nucleofection and zygote microinjection of LINE antisense oligos, followed by RNA FISH validation. This protocol can be used in development, as well as other cell types where LINE1 is believed to be expressed. For complete information on the use and execution of this protocol, please refer to Percharde et al. (2018).


Asunto(s)
Técnicas de Silenciamiento del Gen/métodos , Elementos de Nucleótido Esparcido Largo/genética , Microinyecciones/métodos , Animales , Embrión de Mamíferos/metabolismo , Desarrollo Embrionario/genética , Regulación del Desarrollo de la Expresión Génica/genética , Ratones , Células Madre Embrionarias de Ratones/metabolismo , Oligonucleótidos Antisentido/genética , Oligonucleótidos Antisentido/farmacología , ARN/metabolismo , ARN Nuclear/metabolismo , Cigoto/metabolismo
9.
Reproduction ; 161(6): 697-707, 2021 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-33835048

RESUMEN

Elucidating the mechanisms underpinning fertilisation is essential to optimising IVF procedures. One of the critical steps involves paternal chromatin reprogramming, in which compacted sperm chromatin packed by protamines is removed by oocyte factors and new histones, including histone H3.3, are incorporated. HIRA is the main H3.3 chaperone governing this protamine-to-histone exchange. Failure of this step results in abnormally fertilised zygotes containing only one pronucleus (1PN), in contrast to normal two-pronuclei (2PN) zygotes. 1PN zygotes are frequently observed in IVF treatments, but the genotype-phenotype correlation remains elusive. We investigated the maternal functions of two other molecules of the HIRA complex, Cabin1 and Ubn1, in mouse. Loss-of-function Cabin1 and Ubn1 mouse models were developed: their zygotes displayed an abnormal 1PN zygote phenotype. We then studied human 1PN zygotes and found that the HIRA complex was absent in 1PN zygotes that lacked the male pronucleus. This shows that the role of the HIRA complex in male pronucleus formation potentially has coherence from mice to humans. Furthermore, rescue experiments in mouse showed that the abnormal 1PN phenotype derived from Hira mutants could be resolved by overexpression of HIRA. We have demonstrated that HIRA complex regulates male pronucleus formation in mice and is implicated in humans, that both CABIN1 and UBN1 components of the HIRA complex are equally essential for male pronucleus formation, and that rescue is feasible.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas de Ciclo Celular/metabolismo , Núcleo Celular/genética , Ensamble y Desensamble de Cromatina , Chaperonas de Histonas/metabolismo , Histonas/metabolismo , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismo , Cigoto/fisiología , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Proteínas de Ciclo Celular/genética , Femenino , Fertilización In Vitro , Chaperonas de Histonas/genética , Histonas/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Proteínas Nucleares/genética , Fenotipo , Factores de Transcripción/genética , Cigoto/citología
10.
Reproduction ; 161(3): V11-V14, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33275118

RESUMEN

Ectopic pregnancy (EP) is defined as the implantation of an embryo outside of the uterus and is a leading cause of first trimester maternal mortality and morbidity. This article discusses a possible role for epithelial to mesenchymal transition in the pathogenesis of EP, given the notable similarity of protein expression between the two processes.


Asunto(s)
Transición Epitelial-Mesenquimal , Embarazo Ectópico , Implantación del Embrión , Femenino , Humanos , Embarazo , Primer Trimestre del Embarazo , Embarazo Ectópico/etiología , Útero
11.
Int J Mol Sci ; 21(4)2020 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-32070012

RESUMEN

Meiotic maturation of oocyte relies on pre-synthesised maternal mRNA, the translation of which is highly coordinated in space and time. Here, we provide a detailed polysome profiling protocol that demonstrates a combination of the sucrose gradient ultracentrifugation in small SW55Ti tubes with the qRT-PCR-based quantification of 18S and 28S rRNAs in fractionated polysome profile. This newly optimised method, named Scarce Sample Polysome Profiling (SSP-profiling), is suitable for both scarce and conventional sample sizes and is compatible with downstream RNA-seq to identify polysome associated transcripts. Utilising SSP-profiling we have assayed the translatome of mouse oocytes at the onset of nuclear envelope breakdown (NEBD)-a developmental point, the study of which is important for furthering our understanding of the molecular mechanisms leading to oocyte aneuploidy. Our analyses identified 1847 transcripts with moderate to strong polysome occupancy, including abundantly represented mRNAs encoding mitochondrial and ribosomal proteins, proteasomal components, glycolytic and amino acids synthetic enzymes, proteins involved in cytoskeleton organization plus RNA-binding and translation initiation factors. In addition to transcripts encoding known players of meiotic progression, we also identified several mRNAs encoding proteins of unknown function. Polysome profiles generated using SSP-profiling were more than comparable to those developed using existing conventional approaches, being demonstrably superior in their resolution, reproducibility, versatility, speed of derivation and downstream protocol applicability.


Asunto(s)
Membrana Nuclear/genética , Oocitos/crecimiento & desarrollo , Polirribosomas/genética , Proteínas de Unión al ARN/genética , Animales , Femenino , Regulación del Desarrollo de la Expresión Génica/genética , Meiosis/genética , Ratones , Membrana Nuclear/metabolismo , Oocitos/metabolismo , ARN Mensajero Almacenado/genética , ARN Ribosómico 18S/genética , ARN Ribosómico 28S/genética , RNA-Seq
12.
IEEE Trans Neural Netw Learn Syst ; 31(12): 5639-5644, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32071005

RESUMEN

In linear support vector regression (SVR), the regularization and error sensitivity parameters are used to avoid overfitting the training data. A proper selection of parameters is very essential for obtaining a good model, but the search process may be complicated and time-consuming. In an earlier work by Chu et al. (2015), an effective parameter-selection procedure by using warm-start techniques to solve a sequence of optimization problems has been proposed for linear classification. We extend their techniques to linear SVR, but address some new and challenging issues. In particular, linear classification involves only the regularization parameter, but linear SVR has an extra error sensitivity parameter. We investigate the effective range of each parameter and the sequence in checking the two parameters. Based on this work, an effective tool for the selection of parameters for linear SVR has been available for public use.

13.
J Formos Med Assoc ; 118(8): 1193-1201, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30922614

RESUMEN

BACKGROUND/PURPOSE: Physicians' and dentists' knowledge of levamisole-induced agranulocytosis or pancytopenia remains incomplete. This study aimed to evaluate the treatment effectiveness of levamisole plus prednisolone on oral lichen planus (OLP) patients with emphasis on levamisole-induced hematological changes. METHODS: Ninety patients with erosive OLP were given 120 mg/day new levamisole (Levazol) and 15 mg/day prednisolone for three consecutive days each week. Three cases with levamisole-induced blood-cytopenias were assessed and treated within one year. RESULTS: Most patients reported significant pain relief and showed no evidence of erosive OLP after 4-8 weeks of treatment with few side effects; nevertheless, three female patients developed agranulocytosis or granulocytopenia with concomitant thrombocytopenia or pancytopenia within 2-6 weeks after levamisole (Levazol) treatment. One case with previously unknown double episodes of agranulocytosis revealed her first episode following interruption of levamisole (Decaris) treatment for 4 months. High fever and sore throat were the most common symptoms, but two agranulocytosis cases remained asymptomatic one week before diagnosis, and were treated with levamisole withdrawal and empiric antimicrobial initiation as well as utilization of granulocyte colony-stimulating factors. Neutrophil recovery took about 1 week, but over 4 weeks in one of the cases (an elderly patient) with septic shock. CONCLUSION: Agranulocytosis or pancytopenia usually developed within 2 months after levamisole treatment, but it might be delayed. Agranulocytosis was more likely to occur in females and onset was acute. Levamisole is an effective immunomodulator for OLP patients; however, it should be used with caution and administered with regular blood monitoring.


Asunto(s)
Adyuvantes Inmunológicos/efectos adversos , Agranulocitosis/inducido químicamente , Levamisol/efectos adversos , Liquen Plano Oral/tratamiento farmacológico , Pancitopenia/inducido químicamente , Adyuvantes Inmunológicos/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Levamisol/uso terapéutico , Masculino , Persona de Mediana Edad , Prednisolona/uso terapéutico , Resultado del Tratamiento
14.
Cell ; 174(2): 391-405.e19, 2018 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-29937225

RESUMEN

Transposable elements represent nearly half of mammalian genomes and are generally described as parasites, or "junk DNA." The LINE1 retrotransposon is the most abundant class and is thought to be deleterious for cells, yet it is paradoxically highly expressed during early development. Here, we report that LINE1 plays essential roles in mouse embryonic stem cells (ESCs) and pre-implantation embryos. In ESCs, LINE1 acts as a nuclear RNA scaffold that recruits Nucleolin and Kap1/Trim28 to repress Dux, the master activator of a transcriptional program specific to the 2-cell embryo. In parallel, LINE1 RNA mediates binding of Nucleolin and Kap1 to rDNA, promoting rRNA synthesis and ESC self-renewal. In embryos, LINE1 RNA is required for Dux silencing, synthesis of rRNA, and exit from the 2-cell stage. The results reveal an essential partnership between LINE1 RNA, Nucleolin, Kap1, and peri-nucleolar chromatin in the regulation of transcription, developmental potency, and ESC self-renewal.


Asunto(s)
Fosfoproteínas/metabolismo , Proteínas de Unión al ARN/metabolismo , Animales , Diferenciación Celular , Línea Celular , Autorrenovación de las Células , Inmunoprecipitación de Cromatina , Retrovirus Endógenos/genética , Femenino , Proteínas de Homeodominio/antagonistas & inhibidores , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Hibridación Fluorescente in Situ , Masculino , Ratones , Ratones Endogámicos C57BL , Células Madre Embrionarias de Ratones/citología , Células Madre Embrionarias de Ratones/metabolismo , Oligorribonucleótidos Antisentido/metabolismo , Fosfoproteínas/antagonistas & inhibidores , Fosfoproteínas/genética , Interferencia de ARN , ARN Ribosómico/metabolismo , Proteínas de Unión al ARN/antagonistas & inhibidores , Proteínas de Unión al ARN/genética , Proteína 28 que Contiene Motivos Tripartito/antagonistas & inhibidores , Proteína 28 que Contiene Motivos Tripartito/genética , Proteína 28 que Contiene Motivos Tripartito/metabolismo , Regulación hacia Arriba , Nucleolina
15.
Neural Comput ; 30(6): 1673-1724, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29652589

RESUMEN

Deep learning involves a difficult nonconvex optimization problem with a large number of weights between any two adjacent layers of a deep structure. To handle large data sets or complicated networks, distributed training is needed, but the calculation of function, gradient, and Hessian is expensive. In particular, the communication and the synchronization cost may become a bottleneck. In this letter, we focus on situations where the model is distributedly stored and propose a novel distributed Newton method for training deep neural networks. By variable and feature-wise data partitions and some careful designs, we are able to explicitly use the Jacobian matrix for matrix-vector products in the Newton method. Some techniques are incorporated to reduce the running time as well as memory consumption. First, to reduce the communication cost, we propose a diagonalization method such that an approximate Newton direction can be obtained without communication between machines. Second, we consider subsampled Gauss-Newton matrices for reducing the running time as well as the communication cost. Third, to reduce the synchronization cost, we terminate the process of finding an approximate Newton direction even though some nodes have not finished their tasks. Details of some implementation issues in distributed environments are thoroughly investigated. Experiments demonstrate that the proposed method is effective for the distributed training of deep neural networks. Compared with stochastic gradient methods, it is more robust and may give better test accuracy.

16.
J Nucl Med ; 58(6): 961-967, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-27811121

RESUMEN

Precise definition of the mitral valve plane (VP) during segmentation of the left ventricle for SPECT myocardial perfusion imaging (MPI) quantification often requires manual adjustment, which affects the quantification of perfusion. We developed a machine learning approach using support vector machines (SVM) for automatic VP placement. Methods: A total of 392 consecutive patients undergoing 99mTc-tetrofosmin stress (5 min; mean ± SD, 350 ± 54 MBq) and rest (5 min; 1,024 ± 153 MBq) fast SPECT MPI attenuation corrected (AC) by CT and same-day coronary CT angiography were studied; included in the 392 patients were 48 patients who underwent invasive coronary angiography and had no known coronary artery disease. The left ventricle was segmented with standard clinical software (quantitative perfusion SPECT) by 2 experts, adjusting the VP if needed. Two-class SVM models were computed from the expert placements with 10-fold cross validation to separate the patients used for training and those used for validation. SVM probability estimates were used to compute the best VP position. Automatic VP localizations on AC and non-AC images were compared with expert placement on coronary CT angiography. Stress and rest total perfusion deficits and detection of per-vessel obstructive stenosis by invasive coronary angiography were also compared. Results: Bland-Altman 95% confidence intervals (CIs) for VP localization by SVM and experts for AC stress images (bias, 1; 95% CI, -5 to 7 mm) and AC rest images (bias, 1; 95% CI, -7 to 10 mm) were narrower than interexpert 95% CIs for AC stress images (bias, 0; 95% CI, -8 to 8 mm) and AC rest images (bias, 0; 95% CI, -10 to 10 mm) (P < 0.01). Bland-Altman 95% CIs for VP localization by SVM and experts for non-AC stress images (bias, 1; 95% CI, -4 to 6 mm) and non-AC rest images (bias, 2; 95% CI, -7 to 10 mm) were similar to interexpert 95% CIs for non-AC stress images (bias, 0; 95% CI, -6 to 5 mm) and non-AC rest images (bias, -1; 95% CI, -9 to 7 mm) (P was not significant [NS]). For regional detection of obstructive stenosis, ischemic total perfusion deficit areas under the receiver operating characteristic curve for the 2 experts (AUC, 0.79 [95% CI, 0.7-0.87]; AUC, 0.81 [95% CI, 0.73-0.89]) and the SVM (0.82 [0.74-0.9]) for AC data were the same (P = NS) and were higher than those for the unadjusted VP (0.63 [0.53-0.73]) (P < 0.01). Similarly, for non-AC data, areas under the receiver operating characteristic curve for the experts (AUC, 0.77 [95% CI, 0.69-0.89]; AUC, 0.8 [95% CI, 0.72-0.88]) and the SVM (0.79 [0.71-0.87]) were the same (P = NS) and were higher than those for the unadjusted VP (0.65 [0.56-0.75]) (P < 0.01). Conclusion: Machine learning with SVM allows automatic and accurate VP localization, decreasing user dependence in SPECT MPI quantification.


Asunto(s)
Puntos Anatómicos de Referencia/diagnóstico por imagen , Aprendizaje Automático , Válvula Mitral/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón Único/métodos , Puntos Anatómicos de Referencia/patología , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Persona de Mediana Edad , Válvula Mitral/patología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
17.
Reproduction ; 152(6): R211-R222, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27601712

RESUMEN

Gametogenesis (spermatogenesis and oogenesis) is accompanied by the acquisition of gender-specific epigenetic marks, such as DNA methylation, histone modifications and regulation by small RNAs, to form highly differentiated, but transcriptionally silent cell-types in preparation for fertilisation. Upon fertilisation, extensive global epigenetic reprogramming takes place to remove the previously acquired epigenetic marks and produce totipotent zygotic states. It is the aim of this review to delineate the cellular and molecular events involved in maternal, paternal and zygotic epigenetic reprogramming from the time of gametogenesis, through fertilisation, to the initiation of zygotic genome activation for preimplantation embryonic development. Recent studies have begun to uncover the indispensable functions of epigenetic players during gametogenesis, fertilisation and preimplantation embryo development, and a more comprehensive understanding of these early events will be informative for increasing pregnancy success rates, adding particular value to assisted fertility programmes.


Asunto(s)
Reprogramación Celular/genética , Epigénesis Genética , Cigoto/metabolismo , Animales , Regulación del Desarrollo de la Expresión Génica , Humanos , Masculino , Ratones
18.
Curr Opin Genet Dev ; 34: 17-23, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26183187

RESUMEN

Within the first few days of life, the unipotent gametic genomes are rapidly reprogrammed to support emergence of pluripotent cells in the early mammalian embryo. It is now appreciated that this crucial stage of development involves dramatic changes to chromatin at multiple levels, such as DNA methylation, histone modifications, histone mobility, and higher-order chromatin organization. Technological advances are beginning to allow genome-wide views of this chromatin reprogramming, and provide new approaches to functionally dissect its regulation. Here we review recent insights into the dynamic chromatin environment of the early mouse embryo. New data challenge long-held assumptions, for example, with regards to the asymmetry of DNA methylation of the parental genomes or the onset of functional zygotic genome activation. We discuss how impaired chromatin reprogramming can lead to early embryonic lethality, but might also have delayed effects that only manifest later in embryogenesis or postnatally, potentially influencing the propensity for adult-onset diseases.


Asunto(s)
Cromatina/genética , Embrión de Mamíferos , Desarrollo Embrionario/genética , Animales , Ensamble y Desensamble de Cromatina/genética , Metilación de ADN/genética , Regulación del Desarrollo de la Expresión Génica , Genoma , Células Germinativas/crecimiento & desarrollo , Células Germinativas/metabolismo , Ratones
19.
Neural Comput ; 27(8): 1766-95, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26079755

RESUMEN

Newton methods can be applied in many supervised learning approaches. However, for large-scale data, the use of the whole Hessian matrix can be time-consuming. Recently, subsampled Newton methods have been proposed to reduce the computational time by using only a subset of data for calculating an approximation of the Hessian matrix. Unfortunately, we find that in some situations, the running speed is worse than the standard Newton method because cheaper but less accurate search directions are used. In this work, we propose some novel techniques to improve the existing subsampled Hessian Newton method. The main idea is to solve a two-dimensional subproblem per iteration to adjust the search direction to better minimize the second-order approximation of the function value. We prove the theoretical convergence of the proposed method. Experiments on logistic regression, linear SVM, maximum entropy, and deep networks indicate that our techniques significantly reduce the running time of the subsampled Hessian Newton method. The resulting algorithm becomes a compelling alternative to the standard Newton method for large-scale data classification.


Asunto(s)
Algoritmos , Aprendizaje , Redes Neurales de la Computación , Humanos , Práctica Psicológica
20.
Development ; 142(1): 118-27, 2015 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-25480920

RESUMEN

The pluripotent mammalian epiblast undergoes unusually fast cell proliferation. This rapid growth is expected to generate a high transcriptional demand, but the underlying mechanisms remain unknown. We show here that the chromatin remodeler Chd1 is required for transcriptional output and development of the mouse epiblast. Chd1(-/-) embryos exhibit proliferation defects and increased apoptosis, are smaller than controls by E5.5 and fail to grow, to become patterned or to gastrulate. Removal of p53 allows progression of Chd1(-/-) mutants only to E7.0-8.0, highlighting the crucial requirement for Chd1 during early post-implantation development. Chd1(-/-) embryonic stem cells (ESCs) have a self-renewal defect and a genome-wide reduction in transcriptional output at both known mRNAs and intergenic transcripts. These transcriptional defects were only uncovered when cell number-normalized approaches were used, and correlate with a lower engagement of RNAP II with transcribed genes in Chd1(-/-) ESCs. We further show that Chd1 directly binds to ribosomal DNA, and that both Chd1(-/-) epiblast cells in vivo and ESCs in vitro express significantly lower levels of ribosomal RNA. In agreement with these findings, mutant cells in vivo and in vitro exhibit smaller and more elongated nucleoli. Thus, the RNA output by both Pol I and II is reduced in Chd1(-/-) cells. Our data indicate that Chd1 promotes a globally elevated transcriptional output required to sustain the distinctly rapid growth of the mouse epiblast.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Estratos Germinativos/crecimiento & desarrollo , Estratos Germinativos/metabolismo , Transcripción Genética , Animales , Apoptosis/genética , Tipificación del Cuerpo/genética , Ciclo Celular/genética , Cruzamientos Genéticos , ADN Ribosómico/genética , Proteínas de Unión al ADN/deficiencia , Embrión de Mamíferos/citología , Embrión de Mamíferos/metabolismo , Desarrollo Embrionario , Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Femenino , Gastrulación/genética , Regulación del Desarrollo de la Expresión Génica , Masculino , Ratones Endogámicos C57BL , Precursores del ARN/genética
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