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1.
J Colloid Interface Sci ; 674: 653-662, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38950464

RESUMEN

HYPOTHESIS: The study shows for the first time a fivefold difference in the survivability of the bacterium Pseudomonas Aeruginosa (PA) in a realistic respiratory fluid droplet on fomites undergoing drying at different environmental conditions. For instance, in 2023, the annual average outdoor relative humidity (RH) and temperature in London (UK) is 71 % and 11 °C, whereas in New Delhi (India), it is 45 % and 26 °C, showing that disease spread from fomites could have a demographic dependence. Respiratory fluid droplet ejections containing pathogens on inanimate surfaces are crucial in disease spread, especially in nosocomial settings. However, the interplay between evaporation dynamics, internal fluid flow and precipitation and their collective influence on the distribution and survivability of pathogens at different environmental conditions are less known. EXPERIMENTS: Shadowgraphy imaging is employed to study evaporation, and optical microscopy imaging is used for precipitation dynamics. Micro-particle image velocimetry (MicroPIV) measurements reveal the internal flow dynamics. Confocal imaging of fluorescently labelled PA elucidates the bacterial distribution within the deposits. FINDINGS: The study finds that the evaporation rate is drastically impeded during drying at elevated solutal concentrations, particularly at high RH and low temperature conditions. MicroPIV shows reduced internal flow under high RH and low temperature (low evaporation rate) conditions. Evaporation rate influences crystal growth, with delayed efflorescence and extending crystallization times. PA forms denser peripheral arrangements under high evaporation rates and shows a fivefold increase in survivability under low evaporation rates. These findings highlight the critical impact of environmental conditions on pathogen persistence and disease spread from inanimate surfaces.

2.
Indian Heart J ; 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38878964

RESUMEN

OBJECTIVE: To evaluate paroxysmal atrial fibrillation (AF) prevalence in Indian adults who completed 24-Hour Holter monitoring. METHODS: A total of 23,847 patients (36.9 % women) were analyzed for AF duration using a software algorithm. RESULTS: AF was diagnosed in 4153 (17.4 %) patients with a median AF duration of 13 min and 55 s. CONCLUSION: AF prevalence was high and largely untreated. The short duration of AF episodes indicates a low likelihood of detection during clinical visits, highlighting its potential underestimation in Indian healthcare.

3.
Soft Matter ; 19(47): 9239-9253, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-37999932

RESUMEN

In the present work, experiments are conducted to understand the consequence of stresses generated by flowing fluid on the bacterial morphology and virulence in microfluidic channels. We consider Klebsiella pneumoniae (KP, a clinical isolate), an ESKAPE pathogen, to be the model bacteria responsible for blood stream infections, bacteremia, including pneumonia, urinary tract infections and more. Four different stress conditions are generated by changing the flow rate and channel geometry subsequently altering the shear rate and stressing time (τ). We observe significant changes in the structural aspects of the stressed bacteria. With an increase in stressing parameters, the viability of the bacterial sample deteriorated. Most importantly, these stressed samples proliferate much more than unstressed samples inside the RAW264.7 murine macrophages. The results shed light on the complex relationship between flow stresses and bacterial virulence. Furthermore, the bacterial samples are challenged with ciprofloxacin to see how they behave under different stress conditions. The observations presented in the present study can be extended to model deadly diseases including bacteremia using organ-on-a-chip technology and to understand bacterial pathogenicity under realistic environments.


Asunto(s)
Bacteriemia , Infecciones por Klebsiella , Animales , Ratones , Klebsiella pneumoniae , Infecciones por Klebsiella/tratamiento farmacológico , Infecciones por Klebsiella/microbiología , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Antibacterianos
4.
Cureus ; 14(7): e27016, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35989848

RESUMEN

BACKGROUND: Substance use disorders (SUDs) are considered to be a major risk factor for cardiovascular disorders (CVDs). In 2019, as per the National Drug Use and Health Survey (NSDUH), 20.4 million American adults suffered from a substance use disorder. The main purpose of this study is to determine the prevalence of several SUDs (cigarette smoking, cigar, smokeless tobacco, marijuana, cocaine/heroin/methamphetamine, and injectable illegal drug) amongst patients diagnosed with various CVDs (angina pectoris, myocardial infarction, and coronary heart disease). METHODS: This is a retrospective cross-sectional study carried out using the National Health and Nutrition Examination Survey (NHANES) database from 2013 to 2018, and respondents with CVDs were recognized using questionnaires. Different SUDs (active history) were identified amongst the adult population with a history of CVDs and without CVDs. Univariate analysis was performed using chi-square and unpaired t-test/Mann-Whitney test to identify characteristics of respondents with CVDs and mix effect multivariable logistic regression models were generated to find the prevalence of SUDs amongst the CVD population. Datasets were analyzed using Statistical Analysis System (SAS) software, and the p-value of < 0.05 was considered statistically significant. RESULTS: Of the 263465 respondents, 7.90% respondents were diagnosed with CVDs and were noted to be in older age group (median age: 69 years). CVDs were more prevalent amongst 66-years and above (19.36% vs. 45-64 years: 6.81% vs. 18-44 years: 1.17%), male (10.40% vs. female: 5.66%), Non-Hispanic White race (10.92%), and lower annual household income population (<$25000 vs. >$100,000:12.21% vs. 4.01%) (p<0.0001). When compared with respondents without a history of CVDs, respondents with a history of CVDs were noted to be more prevalent with a concurrent diagnosis of hypertension (85.98% vs. 79.53%), hypercholesterolemia (68.78% vs. 34.54%), diabetes (37.86% vs. 12.70%), stroke (17.4% vs. 2.71%), and congestive heart failure (28.80% vs. 1.31%) (p<0.0001). History of CVDs were more prevalent amongst the respondents using marijuana (overall 53.14%; CVD vs. no-CVD 65.42% vs. 52.81%; p<0.0001), cigarette smoking (60.47% vs. 40.41%; p<0.0001), cigar-smoking (47.05% vs. 35.58%; p<0.0001), methamphetamine/cocaine/heroin (23.82% vs. 16.71%; p<0.0001), smokeless tobacco use (18.53% vs. 14.59%; p<0.0001), and injectable illegal drug use (4.67% vs. 2.43%; p<0.0001). Additionally, prevalence of history of CVDs was almost double in respondents using cigarettes without filters (2.28% vs. 1.10%; p<0.0001) when compared with respondents using cigarettes with filters. CONCLUSION: Respondents who used marijuana or hashish, injectable illegal drugs, and e-cigars were at elevated risk for cardiovascular disorders. Providing situational awareness and offering a good support system can be a strategy to prevent the development of cardiovascular disorders among substance users.

5.
J Colloid Interface Sci ; 623: 541-551, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35598483

RESUMEN

HYPOTHESIS: Vortex droplet interaction is crucial for understanding the route of disease transmission through expiratory jet where several such embedded droplets continuously interact with vortical structures of different strengths and sizes. EXPERIMENTS: A train of vortex rings with different vortex strength, quantified with vortex Reynolds number (Re'=0,53,221,297) are made to interact with an isolated levitated droplet, and the evolution dynamics is captured using shadowgraphy, particle image velocimetry (PIV), and backlight imaging technique. NaCl-DI water solution of 0, 1, 10 and 20 wt% concentrations are used as test fluids for the droplet. FINDINGS: The results show the dependence of evaporation characteristics on vortex strength, while the crystallization dynamics was found to be independent of it. A reduction of 12.23% and 14.6% in evaporation time was seen in case of de-ionized (DI) water and 1% wt NaCl solution respectively in presence of vortex ring train at Re'=221. In contrast to this, a minimal reduction in evaporation time (0.6% and 0.9% for DI water and 1% wt NaCl solution, respectively) is observed when Re' is increased from 221 to 297. The mechanisms for evaporation time reduction due to enhancement of convective heat and mass transfer from the droplet and shearing away of vapor layer by vortex ring interaction are discussed in this work.


Asunto(s)
Aerosoles y Gotitas Respiratorias , Cloruro de Sodio , Cristalización , Gases , Cloruro de Sodio/química , Agua/química
6.
Proc Natl Acad Sci U S A ; 117(44): 27354-27364, 2020 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-33067396

RESUMEN

A high percentage of pediatric gliomas and bone tumors reportedly harbor missense mutations at glycine 34 in genes encoding histone variant H3.3. We find that these H3.3 G34 mutations directly alter the enhancer chromatin landscape of mesenchymal stem cells by impeding methylation at lysine 36 on histone H3 (H3K36) by SETD2, but not by the NSD1/2 enzymes. The reduction of H3K36 methylation by G34 mutations promotes an aberrant gain of PRC2-mediated H3K27me2/3 and loss of H3K27ac at active enhancers containing SETD2 activity. This altered histone modification profile promotes a unique gene expression profile that supports enhanced tumor development in vivo. Our findings are mirrored in G34W-containing giant cell tumors of bone where patient-derived stromal cells exhibit gene expression profiles associated with early osteoblastic differentiation. Overall, we demonstrate that H3.3 G34 oncohistones selectively promote PRC2 activity by interfering with SETD2-mediated H3K36 methylation. We propose that PRC2-mediated silencing of enhancers involved in cell differentiation represents a potential mechanism by which H3.3 G34 mutations drive these tumors.


Asunto(s)
Histonas/genética , Complejo Represivo Polycomb 2/metabolismo , Cromatina/genética , Cromatina/metabolismo , Expresión Génica/genética , Regulación de la Expresión Génica/genética , Glioma/patología , Células HEK293 , N-Metiltransferasa de Histona-Lisina/metabolismo , N-Metiltransferasa de Histona-Lisina/fisiología , Histonas/metabolismo , Humanos , Lisina/metabolismo , Células Madre Mesenquimatosas/metabolismo , Metilación , Mutación/genética , Procesos Neoplásicos , Complejo Represivo Polycomb 1/genética , Complejo Represivo Polycomb 1/metabolismo , Complejo Represivo Polycomb 2/genética , Procesamiento Proteico-Postraduccional
7.
Mol Cell ; 80(4): 726-735.e7, 2020 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-33049227

RESUMEN

Diffuse midline gliomas and posterior fossa type A ependymomas contain the recurrent histone H3 lysine 27 (H3 K27M) mutation and express the H3 K27M-mimic EZHIP (CXorf67), respectively. H3 K27M and EZHIP are competitive inhibitors of Polycomb Repressive Complex 2 (PRC2) lysine methyltransferase activity. In vivo, these proteins reduce overall H3 lysine 27 trimethylation (H3K27me3) levels; however, residual peaks of H3K27me3 remain at CpG islands (CGIs) through an unknown mechanism. Here, we report that EZHIP and H3 K27M preferentially interact with PRC2 that is allosterically activated by H3K27me3 at CGIs and impede its spreading. Moreover, H3 K27M oncohistones reduce H3K27me3 in trans, independent of their incorporation into the chromatin. Although EZHIP is not found outside placental mammals, expression of human EZHIP reduces H3K27me3 in Drosophila melanogaster through a conserved mechanism. Our results provide mechanistic insights for the retention of residual H3K27me3 in tumors driven by H3 K27M and EZHIP.


Asunto(s)
Cromatina/genética , Metilación de ADN , Regulación Neoplásica de la Expresión Génica , Histonas/genética , Mutación , Proteínas Oncogénicas/metabolismo , Complejo Represivo Polycomb 2/metabolismo , Regulación Alostérica , Animales , Islas de CpG , Drosophila melanogaster , Humanos , Ratones , Proteínas Oncogénicas/genética , Complejo Represivo Polycomb 2/genética
8.
Cancer Discov ; 10(12): 1968-1987, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32967858

RESUMEN

Glycine 34-to-tryptophan (G34W) substitutions in H3.3 arise in approximately 90% of giant cell tumor of bone (GCT). Here, we show H3.3 G34W is necessary for tumor formation. By profiling the epigenome, transcriptome, and secreted proteome of patient samples and tumor-derived cells CRISPR-Cas9-edited for H3.3 G34W, we show that H3.3K36me3 loss on mutant H3.3 alters the deposition of the repressive H3K27me3 mark from intergenic to genic regions, beyond areas of H3.3 deposition. This promotes redistribution of other chromatin marks and aberrant transcription, altering cell fate in mesenchymal progenitors and hindering differentiation. Single-cell transcriptomics reveals that H3.3 G34W stromal cells recapitulate a neoplastic trajectory from a SPP1+ osteoblast-like progenitor population toward an ACTA2+ myofibroblast-like population, which secretes extracellular matrix ligands predicted to recruit and activate osteoclasts. Our findings suggest that H3.3 G34W leads to GCT by sustaining a transformed state in osteoblast-like progenitors, which promotes neoplastic growth, pathologic recruitment of giant osteoclasts, and bone destruction. SIGNIFICANCE: This study shows that H3.3 G34W drives GCT tumorigenesis through aberrant epigenetic remodeling, altering differentiation trajectories in mesenchymal progenitors. H3.3 G34W promotes in neoplastic stromal cells an osteoblast-like progenitor state that enables undue interactions with the tumor microenvironment, driving GCT pathogenesis. These epigenetic changes may be amenable to therapeutic targeting in GCT.See related commentary by Licht, p. 1794.This article is highlighted in the In This Issue feature, p. 1775.


Asunto(s)
Neoplasias Óseas/genética , Tumor Óseo de Células Gigantes/genética , Células Madre Mesenquimatosas/metabolismo , Osteoblastos/metabolismo , Diferenciación Celular , Humanos
9.
Nat Commun ; 10(1): 2146, 2019 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-31086175

RESUMEN

Posterior fossa type A (PFA) ependymomas exhibit very low H3K27 methylation and express high levels of EZHIP (Enhancer of Zeste Homologs Inhibitory Protein, also termed CXORF67). Here we find that a conserved sequence in EZHIP is necessary and sufficient to inhibit PRC2 catalytic activity in vitro and in vivo. EZHIP directly contacts the active site of the EZH2 subunit in a mechanism similar to the H3 K27M oncohistone. Furthermore, expression of H3 K27M or EZHIP in cells promotes similar chromatin profiles: loss of broad H3K27me3 domains, but retention of H3K27me3 at CpG islands. We find that H3K27me3-mediated allosteric activation of PRC2 substantially increases the inhibition potential of EZHIP and H3 K27M, providing a mechanism to explain the observed loss of H3K27me3 spreading in tumors. Our data indicate that PFA ependymoma and DIPG are driven in part by the action of peptidyl PRC2 inhibitors, the K27M oncohistone and the EZHIP 'oncohistone-mimic', that dysregulate gene silencing to promote tumorigenesis.


Asunto(s)
Neoplasias Encefálicas/genética , Ependimoma/genética , Glioma/genética , Proteínas Oncogénicas/metabolismo , Complejo Represivo Polycomb 2/metabolismo , Animales , Neoplasias Encefálicas/patología , Carcinogénesis/genética , Línea Celular Tumoral , Cromatina/metabolismo , Islas de CpG , Fosa Craneal Posterior , Conjuntos de Datos como Asunto , Embrión de Mamíferos , Ependimoma/patología , Fibroblastos , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Glioma/patología , Células HEK293 , Histonas , Humanos , Ratones , Proteínas Oncogénicas/genética , Cultivo Primario de Células , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo
10.
Proc Natl Acad Sci U S A ; 116(17): 8295-8300, 2019 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-30967505

RESUMEN

Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of Polycomb Repressor Complex 2 (PRC2), the enzyme that catalyzes monomethylation, dimethylation, and trimethylation of lysine 27 on histone H3 (H3K27). Trimethylation at H3K27 (H3K27me3) is associated with transcriptional silencing of developmentally important genes. Intriguingly, H3K27me3 is mutually exclusive with H3K36 trimethylation on the same histone tail. Disruptions in this cross-talk result in aberrant H3K27/H3K36 methylation patterns and altered transcriptional profiles that have been implicated in tumorigenesis and other disease states. Despite their importance, the molecular details of how PRC2 "senses" H3K36 methylation are unclear. We demonstrate that PRC2 is activated in cis by the unmodified side chain of H3K36, and that this activation results in a fivefold increase in the kcat of its enzymatic activity catalyzing H3K27 methylation compared with activity on a substrate methylated at H3K36. Using a photo-cross-linking MS strategy and histone methyltransferase activity assays on PRC2 mutants, we find that EZH2 contains a specific sensing pocket for the H3K36 methylation state that allows the complex to distinguish between modified and unmodified H3K36 residues, altering enzymatic activity accordingly to preferentially methylate the unmodified nucleosome substrate. We also present evidence that this process may be disrupted in some cases of Weaver syndrome.


Asunto(s)
Proteína Potenciadora del Homólogo Zeste 2 , Histonas , Sitios de Unión/genética , Proteína Potenciadora del Homólogo Zeste 2/química , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Histonas/química , Histonas/metabolismo , Humanos , Modelos Moleculares , Mutación , Unión Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
11.
Nat Commun ; 10(1): 1262, 2019 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-30890717

RESUMEN

Lys-27-Met mutations in histone 3 genes (H3K27M) characterize a subgroup of deadly gliomas and decrease genome-wide H3K27 trimethylation. Here we use primary H3K27M tumor lines and isogenic CRISPR-edited controls to assess H3K27M effects in vitro and in vivo. We find that whereas H3K27me3 and H3K27me2 are normally deposited by PRC2 across broad regions, their deposition is severely reduced in H3.3K27M cells. H3K27me3 is unable to spread from large unmethylated CpG islands, while H3K27me2 can be deposited outside these PRC2 high-affinity sites but to levels corresponding to H3K27me3 deposition in wild-type cells. Our findings indicate that PRC2 recruitment and propagation on chromatin are seemingly unaffected by K27M, which mostly impairs spread of the repressive marks it catalyzes, especially H3K27me3. Genome-wide loss of H3K27me3 and me2 deposition has limited transcriptomic consequences, preferentially affecting lowly-expressed genes regulating neurogenesis. Removal of H3K27M restores H3K27me2/me3 spread, impairs cell proliferation, and completely abolishes their capacity to form tumors in mice.


Asunto(s)
Neoplasias Encefálicas/genética , Cromatina/metabolismo , Glioblastoma/genética , Histonas/genética , Complejo Represivo Polycomb 2/metabolismo , Adolescente , Anciano , Animales , Neoplasias Encefálicas/patología , Sistemas CRISPR-Cas , Carcinogénesis/genética , Línea Celular Tumoral , Proliferación Celular/genética , Niño , Islas de CpG/genética , Metilación de ADN/genética , Epigénesis Genética , Femenino , Edición Génica/métodos , Regulación Neoplásica de la Expresión Génica , Glioblastoma/patología , Células HEK293 , Código de Histonas/genética , Histonas/metabolismo , Humanos , Lisina/genética , Masculino , Metionina/genética , Ratones , Ratones Endogámicos NOD , Ratones SCID , Mutación , Neurogénesis/genética , Ensayos Antitumor por Modelo de Xenoinjerto
12.
Mol Cell ; 74(1): 185-195.e4, 2019 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-30797686

RESUMEN

Reprogramming cell fate during the first stages of embryogenesis requires that transcriptional activators gain access to the genome and remodel the zygotic transcriptome. Nonetheless, it is not clear whether the continued activity of these pioneering factors is required throughout zygotic genome activation or whether they are only required early to establish cis-regulatory regions. To address this question, we developed an optogenetic strategy to rapidly and reversibly inactivate the master regulator of genome activation in Drosophila, Zelda. Using this strategy, we demonstrate that continued Zelda activity is required throughout genome activation. We show that Zelda binds DNA in the context of nucleosomes and suggest that this allows Zelda to occupy the genome despite the rapid division cycles in the early embryo. These data identify a powerful strategy to inactivate transcription factor function during development and suggest that reprogramming in the embryo may require specific, continuous pioneering functions to activate the genome.


Asunto(s)
Reprogramación Celular , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Proteínas Nucleares/genética , Animales , Animales Modificados Genéticamente , Sitios de Unión , ADN/genética , ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Drosophila melanogaster/metabolismo , Regulación del Desarrollo de la Expresión Génica , Silenciador del Gen , Proteínas Nucleares/metabolismo , Nucleosomas/genética , Nucleosomas/metabolismo , Optogenética , Unión Proteica , Fase S
13.
Sci Rep ; 7(1): 15867, 2017 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-29158537

RESUMEN

The rewards of using plants and plant metabolites over other biological methods for nanoparticle synthesis have fascinated researchers to investigate mechanisms of metal ions uptake and bio-reduction by plants. Here, green chemistry were employed for the synthesis of silver nanoparticles (AgNPs) using leaf extracts of Ocimum Sanctum (Tulsi) and its derivative quercetin (flavonoid present in Tulsi) separately as precursors to investigate the role of biomolecules present in Tulsi in the formation of AgNPs from cationic silver under different physicochemical conditions such as pH, temperature, reaction time and reactants concentration. The size, shape, morphology, and stability of resultant AgNPs were investigated by optical spectroscopy (absorption, photoluminescence (PL), PL-lifetime and Fourier transform infrared), X-ray diffraction (XRD) analysis, and transmission electron microscopy (TEM). The enhanced antibacterial activity of AgNPs against E-Coli gram-negative bacterial strains was analyzed based on the zone of inhibition and minimal inhibitory concentration (MIC) indices. The results of different characterization techniques showed that AgNPs synthesized using both leaf extract and neat quercetin separately followed the same optical, morphological, and antibacterial characteristics, demonstrating that biomolecules (quercetin) present in Tulsi are mainly responsible for the reduction of metal ions to metal nanoparticles.


Asunto(s)
Antibacterianos/farmacología , Flavonoides/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Nanopartículas del Metal/química , Antibacterianos/química , Escherichia coli/efectos de los fármacos , Escherichia coli/patogenicidad , Flavonoides/química , Bacterias Gramnegativas/patogenicidad , Tecnología Química Verde , Humanos , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Transmisión , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Plantas Medicinales/química , Plata/química , Espectroscopía Infrarroja por Transformada de Fourier
14.
Sci Transl Med ; 8(366): 366ra161, 2016 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-27881822

RESUMEN

Childhood posterior fossa (PF) ependymomas cause substantial morbidity and mortality. These tumors lack recurrent genetic mutations, but a subset of these ependymomas exhibits CpG island (CpGi) hypermethylation [PF group A (PFA)], implicating epigenetic alterations in their pathogenesis. Further, histological grade does not reliably predict prognosis, highlighting the importance of developing more robust prognostic markers. We discovered global H3K27me3 reduction in a subset of these tumors (PF-ve ependymomas) analogous to H3K27M mutant gliomas. PF-ve tumors exhibited many clinical and biological similarities with PFA ependymomas. Genomic H3K27me3 distribution showed an inverse relationship with CpGi methylation, suggesting that CpGi hypermethylation drives low H3K27me3 in PF-ve ependymomas. Despite CpGi hypermethylation and global H3K27me3 reduction, these tumors showed DNA hypomethylation in the rest of the genome and exhibited increased H3K27me3 genomic enrichment at limited genomic loci similar to H3K27M mutant gliomas. Combined integrative analysis of PF-ve ependymomas with H3K27M gliomas uncovered common epigenetic deregulation of select factors that control radial glial biology, and PF radial glia in early human development exhibited reduced H3K27me3. Finally, H3K27me3 immunostaining served as a biomarker of poor prognosis and delineated radiologically invasive tumors, suggesting that reduced H3K27me3 may be a prognostic indicator in PF ependymomas.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Metilación de ADN , Ependimoma/diagnóstico , Ependimoma/metabolismo , Histonas/química , Neoplasias Encefálicas/genética , Sistema Nervioso Central/patología , Niño , Islas de CpG , Ependimoma/genética , Epigénesis Genética , Perfilación de la Expresión Génica , Genoma Humano , Humanos , Mutación , Pronóstico , Resultado del Tratamiento
15.
J Clin Diagn Res ; 10(3): OC03-6, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27134910

RESUMEN

INTRODUCTION: We very often face pacemaker implanted patients during follow-up with shortness of breath and effort intolerance inspite of normal clinical parameters. AIM: The aim of our study is to evaluate the cause of effort intolerance and probable cause of sub-clinical Congestive Cardiac Failure (CCF) in a case of long term Right Ventricular (RV) apical pacing on global Left Ventricular (LV) function non- invasively by echocardiography. MATERIALS AND METHODS: We studied 54 patients (Male 42, Female 12) of complete heart block (CHB) with RV apical pacing (40 VVI and 14 DCP). Mean duration of pacing was 58+4 months. All patients underwent 24 hours Holter monitoring to determine the percentage of ventricular pacing beats. 2-D Echocardiography was done to assess the regional wall motion of abnormality and global LV ejection fraction by modified Simpson's rule. These methods were coupled with the Doppler derived Myocardial Performance Index (MPI), tissue Doppler imaging, and mechanical regional dyssynchrony with 3-D Echocardiography. Data were analysed from 54 RV- apical paced patients and compared with age and body surface area of 60 controlled subjects (Male 46, Female 14). RESULTS: Evaluation of LV function in 54 patients demonstrated regional wall motion abnormality and Doppler study revealed both LV systolic and diastolic dysfunction compare with control subjects (regional wall motion abnormality 80±6% vs 30±3% with p-value<0.0001) which is proportional to the percentage of ventricular pacing beats (mean paced beat 78%). Global LVEF 50±4% vs 60±2% (p-valve <0.0001) and MPI 0.46 ±0.12 v/s 0.36±0.09 (p-value <0.0001). CONCLUSION: RV-apical pacing induces iatrogenic electrical dyssynchrony which leads to remodeling of LV and produces mechanical dyssynchrony which is responsible for LV dysfunction. Alternate site of RV pacing and/or biventricular pacing should be done to maintain biventricular electrical synchrony which will preserve the LV function.

16.
Science ; 352(6287): 844-9, 2016 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-27174990

RESUMEN

Several types of pediatric cancers reportedly contain high-frequency missense mutations in histone H3, yet the underlying oncogenic mechanism remains poorly characterized. Here we report that the H3 lysine 36-to-methionine (H3K36M) mutation impairs the differentiation of mesenchymal progenitor cells and generates undifferentiated sarcoma in vivo. H3K36M mutant nucleosomes inhibit the enzymatic activities of several H3K36 methyltransferases. Depleting H3K36 methyltransferases, or expressing an H3K36I mutant that similarly inhibits H3K36 methylation, is sufficient to phenocopy the H3K36M mutation. After the loss of H3K36 methylation, a genome-wide gain in H3K27 methylation leads to a redistribution of polycomb repressive complex 1 and de-repression of its target genes known to block mesenchymal differentiation. Our findings are mirrored in human undifferentiated sarcomas in which novel K36M/I mutations in H3.1 are identified.


Asunto(s)
Neoplasias Óseas/genética , Carcinogénesis/genética , Condroblastoma/genética , Histonas/genética , Células Madre Mesenquimatosas/patología , Células Madre Neoplásicas/patología , Sarcoma/genética , Animales , Neoplasias Óseas/patología , Carcinogénesis/patología , Preescolar , Condroblastoma/patología , Regulación Neoplásica de la Expresión Génica , Histonas/metabolismo , Humanos , Lisina/genética , Células Madre Mesenquimatosas/metabolismo , Metionina/genética , Metilación , Metiltransferasas/genética , Metiltransferasas/metabolismo , Ratones , Mutación , Mutación Missense , Células Madre Neoplásicas/metabolismo , Nucleosomas/genética , Complejo Represivo Polycomb 1/metabolismo , Sarcoma/patología
17.
Proc Natl Acad Sci U S A ; 113(22): 6182-7, 2016 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-27185940

RESUMEN

Lysine to methionine (K-to-M) mutations in genes encoding histone H3 are thought to drive a subset of pediatric brain and bone cancers. These high-frequency K-to-M mutations occur at sites of methylation on histone H3, and tumors containing the mutant histones exhibit a global loss of specific histone methylation marks. Previous studies showed that K-to-M mutant histones, also known as oncohistones, are potent orthosteric inhibitors of specific Su(var)3-9, Enhancer-of-zeste, Trithorax (SET) domain methyltransferases. However, the biochemical and biophysical details of the interaction between K-to-M mutant histones and the respective SET domain methyltransferases are currently unknown. Here, we use the histone H3K9-directed methyltransferase G9a as a model to explore the mechanism of inhibition by K-to-M oncohistones. X-ray cocrystal structures revealed that the K9M residue of histone H3 occupies the active site cavity of G9a, and kinetic analysis indicates competitive inhibition of G9a by histone H3K9M. Additionally, we find that the cofactor S-adenosyl methionine (SAM) is necessary for stable interaction between G9a and H3K9M histone. Consistent with the formation of a ternary complex, we find that the inhibitory peptide is uncompetitive with regard to SAM. These data and others indicate that K-to-M oncohistones promote global loss of specific lysine methylation through sequestration and inhibition of SAM-bound SET domain methyltransferases.


Asunto(s)
N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , Histonas/genética , Lisina/genética , Metionina/genética , Mutación/genética , S-Adenosilmetionina/farmacología , Cristalografía por Rayos X , N-Metiltransferasa de Histona-Lisina/genética , Histonas/química , Humanos , Lisina/química , Metionina/química , Fragmentos de Péptidos/química , Especificidad por Sustrato
18.
J Clin Diagn Res ; 9(12): OC06-8, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26816930

RESUMEN

INTRODUCTION: Acute Myocardial Infarction (AMI) is a life threatening medical emergency which needs urgent medical attention. It is one of the major cause of mortality and morbidity throughout the world. AIM: The aim of the present study was to assess the coronary artery status by Coronary Angiography (CAG) after first survival of the Acute Myocardial Infarction (AMI) and to correlate the CAG findings with Coronary Artery Disease (CAD) Risk Factor (RF) and effect of early thrombolysis. MATERIALS AND METHODS: CAG was done on 870 patients consecutively from June 2013 to May 2015. Age, Gender, Body Mass Index (BMI), CAD risk factors (RF) such as Type 2 diabetes mellitus (T2 DM), hypertension, dyslipidaemia, smoking status and history of thrombolyctic status were recorded. The correlation between the CAD risk factors (RF) and the CAG findings were statistically analyzed. RESULTS: Coronary heart disease risk factors analysis revealed ≥ three RF in 23.88%, two RF in 29.88% and one RFin 45.86% of patients. CAG showed Single Vessel Disease (SVD) in 236 (27.1%) patients, double vessel disease (DVD) in 220(25.2%) patients, Triple Vessel Disease (TVD) in 252 (28.9%) patients. Multiple coronary artery involvement were found in the high risk group patients, which was found statistically significant (p-value<0.0001). A total of 348/870 (40%) patients were thrombolysed amongst them 80 (22.9%) revealed minimal and/or normal coronary artery which was found statistically significant (p-value<0.0001). CONCLUSION: Higher the coronary risk factors, more the chance of the multiple coronary arteries involvement. All AMI patients should be thrombolysed as early as possible to get the benefit of recanalization of the culprit vessel.

19.
J Am Chem Soc ; 136(39): 13498-501, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25180930

RESUMEN

The histone methyltransferase PRC2 plays a central role in genomic stability and cellular development. Consequently, its misregulation has been implicated in several cancers. Recent work has shown that a histone H3 mutant, where the PRC2 substrate residue Lys27 is replaced by methionine, is also associated with cancer phenotypes and functions as an inhibitor of PRC2. Here we investigate the mechanism of this PRC2 inhibition through kinetic studies and photo-cross-linking. Efficient inhibition is dependent on (1) hydrophobic lysine isosteres blocking the active site, (2) proximal residues, and (3) the H3 tail forming extensive contacts with the EZH2 subunit of PRC2. We further show that naturally occurring post-translational modifications of the same H3 tail, both proximal and distal to K27M, can greatly diminish the inhibition of PRC2. These results suggest that this potent gain of function mutation may be "detoxified" by modulating alternate chromatin modification pathways.


Asunto(s)
Histonas/genética , Histonas/metabolismo , Mutación/genética , Neoplasias/genética , Complejo Represivo Polycomb 2/química , Complejo Represivo Polycomb 2/metabolismo , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Células HeLa , Histonas/química , Humanos , Cinética , Modelos Moleculares , Neoplasias/metabolismo , Complejo Represivo Polycomb 2/antagonistas & inhibidores
20.
Pediatr Cardiol ; 32(8): 1219-22, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21533778

RESUMEN

A congenital left ventricular diverticulum is a rare cardiac malformation. It is a developmental anomaly that occurs during embryogenesis. Presentations vary from asymptomatic patients to sudden death. To date, the treatment described has been surgical correction. The authors report the first transcatheter closure of an isolated congenital left ventricular diverticulum in a 12-year-old symptomatic girl.


Asunto(s)
Divertículo/congénito , Divertículo/terapia , Ventrículos Cardíacos/anomalías , Dispositivo Oclusor Septal , Cateterismo Cardíaco , Niño , Divertículo/diagnóstico por imagen , Divertículo/fisiopatología , Ecocardiografía Transesofágica , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Función Ventricular Izquierda
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