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1.
Int J Mol Sci ; 24(19)2023 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-37834162

RESUMEN

Extracellular vesicles (EVs)-including apoptotic bodies, microvesicles, and exosomes-are released by almost all cell types and contain molecular footprints from their cell of origin, including lipids, proteins, metabolites, RNA, and DNA. They have been successfully isolated from blood, urine, semen, and other body fluids. In this review, we discuss the current understanding of the predictive value of EVs in prostate and renal cancer. We also describe the findings supporting the use of EVs from liquid biopsies in stratifying high-risk prostate/kidney cancer and advanced disease, such as castration-resistant (CRPC) and neuroendocrine prostate cancer (NEPC) as well as metastatic renal cell carcinoma (RCC). Assays based on EVs isolated from urine and blood have the potential to serve as highly sensitive diagnostic studies as well as predictive measures of tumor recurrence in patients with prostate and renal cancers. Overall, we discuss the biogenesis, isolation, liquid-biopsy, and therapeutic applications of EVs in CRPC, NEPC, and RCC.


Asunto(s)
Carcinoma de Células Renales , Exosomas , Vesículas Extracelulares , Neoplasias Renales , Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Carcinoma de Células Renales/patología , Próstata/patología , Neoplasias de la Próstata Resistentes a la Castración/patología , Relevancia Clínica , Neoplasias Renales/metabolismo , Recurrencia Local de Neoplasia/patología , Vesículas Extracelulares/metabolismo , Exosomas/metabolismo
2.
Front Mol Biosci ; 10: 1156821, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37266331

RESUMEN

Emerging evidence suggests that brain derived extracellular vesicles (EVs) and particles (EPs) can cross blood-brain barrier and mediate communication among neurons, astrocytes, microglial, and other cells of the central nervous system (CNS). Yet, a complete understanding of the molecular landscape and function of circulating EVs & EPs (EVPs) remain a major gap in knowledge. This is mainly due to the lack of technologies to isolate and separate all EVPs of heterogeneous dimensions and low buoyant density. In this review, we aim to provide a comprehensive understanding of the neurosecretome, including the extracellular vesicles that carry the molecular signature of the brain in both its microenvironment and the systemic circulation. We discuss the biogenesis of EVPs, their function, cell-to-cell communication, past and emerging isolation technologies, therapeutics, and liquid-biopsy applications. It is important to highlight that the landscape of EVPs is in a constant state of evolution; hence, we not only discuss the past literature and current landscape of the EVPs, but we also speculate as to how novel EVPs may contribute to the etiology of addiction, depression, psychiatric, neurodegenerative diseases, and aid in the real time monitoring of the "living brain". Overall, the neurosecretome is a concept we introduce here to embody the compendium of circulating particles of the brain for their function and disease pathogenesis. Finally, for the purpose of inclusion of all extracellular particles, we have used the term EVPs as defined by the International Society of Extracellular Vesicles (ISEV).

4.
J Virol Methods ; 314: 114687, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36736703

RESUMEN

Wastewater-based epidemiology (WBE) represents an efficient approach for public pathogen surveillance as it provides early warning of disease outbreaks; however, it has not yet been applied to dengue virus (DENV), which might cause endemics via mosquito spread. In this study, a working platform was established to provide direct virus recovery and qPCR quantification from wastewater samples that were artificially loaded with target DENV serotypes I to IV and noncognate spike control viral particles. The results showed qPCR efficiencies of 91.2 %, 94.8 %, 92.6 % and 88.7 % for DENV I, II, III, and IV, respectively, and a broad working range over 6 orders of magnitude using the preferred primer sets. Next, the results revealed that the ultrafiltration method was superior to the skimmed milk flocculation method for recovering either DENV or control viral particles from wastewater. Finally, DENV-2 was loaded simultaneously with the noncognate spike control and could be recovered at comparable levels either in PBS or in wastewater, indicating the applicability of noncognate spike control particles to reflect the efficiency of experimental steps. In conclusion, our data suggest that DENV particles in wastewater could be recovered and quantitatively detected in absolute amounts, indicating the feasibility of DENV surveillance using the WBE approach.


Asunto(s)
Culicidae , Virus del Dengue , Dengue , Animales , Virus del Dengue/genética , Dengue/diagnóstico , Aguas Residuales , Brotes de Enfermedades , Serogrupo
5.
Artículo en Inglés | MEDLINE | ID: mdl-36554889

RESUMEN

This study focused on the effect of acute Judo training on countermovement jump (CMJ) performance and perceived fatigue among a group of highly trained collegiate judo athletes. Twenty male judo athletes participated in this study (age: 20.65 ± 1.22 years, weight: 84.17 ± 28.45 kg). Participants were assessed for CMJperformance changes before, immediately after (0 h), 12 h after, and 24 h after judo training (JT) using unloaded CMJ(CMJunloaded) and loaded CMJ(CMJloaded). All the jumps were performed on a force plate, and the force-time curves were collected for further analysis. Respondents' perceptions were evaluated using the modified rating of perceived exertion (mRPE) before, after (0 h), 12 h, and 24 h after JT. CMJparameters were analyzed at four measured points using a one-way repeated analysis of variance. Effect sizes (ES) and percentage changes before versus 24 h after JT were calculated for comparison. Associations between the CMJparameters and mRPE were analyzed using the Pearson product-moment correlation. The ratio of flight time to contact time significantly decreased, whereas the eccentric duration, concentric duration, and total duration significantly increased (p < 0.05) in both CMJs 24 h after JT. Compared with CMJunloaded, CMJloaded had a significantly lower (p < 0.05) flight time, jump height, peak velocity, and peak power. The mRPE and CMJloaded peak velocity showed moderate- to high-level negative correlation results both 0 and 24 h after training (r = -0.543, p < 0.05; r = -0.479, p < 0.05). In this study, we only observed the effect of fatigue on the neuromuscular (NM) system 24 h after JT. CMJloaded height may help to better determine fatigue state compared with CMJunloaded. According to the results, the neuromuscular effects of fatigue were not observed until 24 h after a single high-intensity training. Therefore, when arranging high-intensity special training or strength and conditioning training, one should reduce the volume of training appropriately to avoid fatigue accumulation and reduce the risk of sports injuries.


Asunto(s)
Atletas , Artes Marciales , Humanos , Masculino , Adulto Joven , Adulto , Fatiga Muscular , Fatiga , Fuerza Muscular
6.
Life Sci ; 311(Pt A): 121135, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36349605

RESUMEN

AIMS: Pancreatic ductal adenocarcinoma (PDAC) constitutes one of the most dismal malignancies worldwide. Despite multidisciplinary involvement in interventions involving surgery, radiotherapy, and chemotherapy, most pancreatic cancer patients eventually develop distant metastasis. S-phase kinase-associated protein 2 (Skp2) plays an important role in cell-cycle regulation in pancreatic cancer. However, the role of Skp2 in individualized PDAC treatment is largely unknown. MAIN METHODS: Immunoblotting, quantitative reverse transcription polymerase chain reaction, cell viability test, chromatin immunoprecipitation assay, and xenograft in vivo assay were performed in parental and Skp2-depleted cells. The immunohistochemistry of Skp2 was analyzed on the tissue microarrays of 45 PDAC cases and mice tissues. KEY FINDINGS: In this study, we observed that Skp2 is a marker for poor prognosis in PDAC patients. Upregulation of the inhibitor of κB (IκB)-inducing kinase-nuclear factor kappa B (NF-κB) signal cascade mediated Skp2 expression thereby promoting epithelial-mesenchymal transition (EMT). Depletion of NF-κB-associated signaling effectively prevented Skp2-mediated pancreatic cancer cell migration. As a functional consequence, Skp2 orchestrated with Myc to induce zinc finger E-box binding homeobox 1 (Zeb1) transcription by recruiting p300 to the Zeb1 promoter independent of Skp2 E3-ligase activity. Therefore, blockade of Skp2 could significantly reduce the expression of Zeb1 and inhibit cancer cell migration. In conclusion, Skp2 regulated Zeb1 activity to control the migration and invasion abilities of pancreatic cancer cells. Skp2 expression in PDAC may affect cell vulnerability to standard chemotherapy regimens. SIGNIFICANCE: Therefore, in patients with PDAC, modulation of Skp2 expression could be a novel strategy for preventing cancer cell metastasis.


Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Ratones , Animales , Proteínas Quinasas Asociadas a Fase-S/genética , Proteínas Quinasas Asociadas a Fase-S/metabolismo , FN-kappa B/metabolismo , Línea Celular Tumoral , Carcinoma Ductal Pancreático/patología , Neoplasias Pancreáticas/patología , Ubiquitinación , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Neoplasias Pancreáticas
7.
iScience ; 25(6): 104414, 2022 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-35663013

RESUMEN

Circulating extracellular vesicles (EVs) contain molecular footprints-lipids, proteins, RNA, and DNA-from their cell of origin. Consequently, EV-associated RNA and proteins have gained widespread interest as liquid-biopsy biomarkers. Yet, an integrative proteo-transcriptomic landscape of EVs and comparison with their cell of origin remains obscure. Here, we report that EVs enrich distinct proteo-transcriptome that does not linearly correlate with their cell of origin. We show that EVs enrich endosomal and extracellular proteins, small RNA (∼13-200 nucleotides) associated with cell differentiation, development, and Wnt signaling. EVs cargo specific RNAs (RNY3, vtRNA, and MIRLET-7) and their complementary proteins (YBX1, IGF2BP2, and SRSF1/2). To ensure an unbiased and independent analyses, we studied 12 cancer cell lines, matching EVs (inhouse and exRNA database), and serum EVs of patients with prostate cancer. Together, we show that EV-RNA-protein complexes may constitute a functional interaction network to protect and regulate molecular access until a function is achieved.

9.
Radiother Oncol ; 149: 249-258, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32592893

RESUMEN

PURPOSE: Neoadjuvant concurrent chemoradiotherapy (CCRT) is a gold standard treatment for patients with stage II/III rectal cancer. B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) is a member of the polycomb group of proteins that are involved in regulating gene expression. High levels of BMI1 have been demonstrated to contribute to the malignant phenotypes of several cancers; however, its relevance in rectal cancer treated with CCRT is largely unknown. METHODS AND MATERIALS: We used two patient cohorts to address the clinical relevance of BMI1 in human cancers. In addition, HT-29 and HCT-116 cells were chosen as our in vitro models to verify the role of BMI1 in cell response to ionizing radiation. Stemness-related proteins were analyzed by western blotting and cell survival was determined using clonogenic assays. RESULTS: BMI1 overexpression was found to significantly correlate with advanced pre-treatment nodal status (N1-N2; p < 0.001), post-treatment tumor stage (T1-T2; p = 0.015), inferior tumor regression grade (p = 0.001), and also an independent prognosis factor in 172 rectal cancer patients receiving CCRT. Serial cell-based functional examination indicated that BMI1 deficiency sensitized cells to radiation treatment by modulating the gene expression of Kruppel-like factor 4 (KLF4) and enhanced radiosensitivity in microsatellite stable (MSS) colorectal cancers. Overexpression of KLF4 partially overcame BMI1-deficiency-mediated γ-H2AX expression after ionizing radiation exposure. Consistent with in vitro data, an analysis of an additional 30 rectal cancer tissue specimens revealed a positive correlation between BMI1 and KLF4 (p = 0.02). CONCLUSION: Higher levels of BMI1 are associated with poor therapeutic response and adverse outcomes in rectal cancer patients receiving CCRT.


Asunto(s)
Terapia Neoadyuvante , Neoplasias del Recto , Animales , Biomarcadores de Tumor , Quimioradioterapia/efectos adversos , Humanos , Factor 4 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel , Ratones , Complejo Represivo Polycomb 1/genética , Pronóstico , Proteínas Proto-Oncogénicas/genética , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/terapia
10.
Am J Cancer Res ; 9(11): 2544-2553, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31815052

RESUMEN

Colorectal cancer (CRC) is one of the most common cancers worldwide. Despite advances in treatment, no treatment modality specific for the different CRC phenotypes has been developed. BMI1 has been previously reported to play an important role in the regulation of cancer stem cells and cell cycle in CRC. However, the role of BMI1 in individualized treatment for CRC is largely unknown. In this study, we found that the apoptotic effect of paclitaxel is more profound in BMI1-depleted cells. The apoptotic effect is exerted by promoting caspase-8-independent apoptotic pathways after combination with paclitaxel in BMI1 knockdown cells. This effect could be totally recovered by pretreatment with caspase inhibitor compared with caspase-8 inhibitor alone. It has been reported that the levels of MCL-1 play a role in regulating cell resistance to paclitaxel treatment. Our data indicated that the downregulation of MCL-1 through the activation of GSK3beta and JNK is driven by BMI1 depletion. Consistent with in vitro data, a synergic anti-growth effect of BMI1 depletion with paclitaxel treatment was shown in vivo. In conclusion, paclitaxel has a stronger suppressive effect on tumor growth and proliferation in CRC with low BMI1 expression. Thus, in CRC patients, paclitaxel could be specifically indicated for patients with low BMI1 expression.

11.
Am J Cancer Res ; 8(9): 1812-1822, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30323973

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease, which is characterized by its high invasiveness, rapid progression, and profound resistance to therapy. Gemcitabine is the first-line treatment option for pancreatic cancer patients, but the overall survival is quite low. Therefore, it is an urgent issue to identify new molecules for improved therapies, with better efficacy and less toxicity. Our previous data indicated that Euchromatic histone-lysine N-methyltransferase 2 (EHMT2) functions as a therapeutic target to override GEM resistance and promote metastasis in the treatment of pancreatic cancer. Here, we screened a small-molecule library of 143 protein kinase inhibitors, to verify cytotoxicity of different inhibitors in EHMT2-depleted cells. We determined that the EHMT2 plays a promising modulating role for targeted PI3K/mTOR inhibition. Our data revealed that EHMT2 down-regulates p27 expression, and this contributes to tumor growth. The depletion of EHMT2, ectopic expression of methyltransferase-dead EHMT2, or treatment with an EHMT2 inhibitor decreases H3K9 methylation of p27 promoter and induces G1 arrest in PANC-1 pancreatic cancer cells. Consistent with these findings, in vivo tumor xenograft models, primary tumors, and the Oncomine database utilizing bioinformatics approaches, also show a negative correlation between EHMT2 and p27. We further demonstrated that low EHMT2 elevated BEZ235 sensitivity through up-regulation of p27 in PDAC cells; high levels of SKP2 decrease BEZ235 responsiveness in PDAC cells. Altogether, our results suggest the EHMT2-p27 axis as a potential marker to modulate cell response to dual PI3K/mTOR inhibition, which might provide a strategy in personalized therapeutics for PDAC patients.

12.
J Agric Food Chem ; 66(37): 9635-9644, 2018 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-30188700

RESUMEN

Di(2-ethylhexyl) phthalate (DEHP) is a common plasticizer that is widely used in many consumer products and medical devices. Humans can be exposed to DEHP through ingestion, inhalation, or dermal absorption. Previous studies on DEHP have focused on its role as an endocrine-disrupting chemical leading to endocrine-related diseases. However, the correlation between DEHP exposure and the progression of colorectal cancer (CRC) is largely unknown. The aim of this study was to investigate the effects of mono(2-ethylhexyl) phthalate (MEHP), an active metabolite of DEHP, on the progression of CRC. Our results showed that treatment with MEHP enriched the population of cancer-stem-cell (CSC)-like cells and upregulated IL-8 expression by inducing the AKT-ß-catenin-TCF4 signaling pathway. Blocking ß-catenin-TCF4-mediated IL-8 expression reversed the MEHP-induced migration and enrichment of CSC-like cells. Consistent with the in vitro data, DEHP treatment increased the levels of nuclear ß-catenin, polyp formation, and invasive adenocarcinoma in a mouse model. Our results suggest that MEHP facilitates the progression of CRC through AKT-ß-catenin signaling.


Asunto(s)
Movimiento Celular/efectos de los fármacos , Neoplasias Colorrectales/fisiopatología , Dietilhexil Ftalato/toxicidad , Interleucina-8/metabolismo , Plastificantes/toxicidad , Proteínas Proto-Oncogénicas c-akt/metabolismo , beta Catenina/metabolismo , Animales , Neoplasias Colorrectales/etiología , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Humanos , Interleucina-8/genética , Ratones , Ratones Endogámicos C57BL , Proteínas Proto-Oncogénicas c-akt/genética , beta Catenina/genética
13.
Phytopathology ; 108(12): 1467-1474, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29975159

RESUMEN

Bacterial soft rot is a devastating disease affecting a variety of vegetable crops worldwide. One strategy for controlling this disease could be the ectopic expression of the plant ferredoxin-like protein (pflp) gene. PFLP was previously shown to intensify pathogen-associated molecular pattern-triggered immunity (PTI), an immune response triggered, for example, by the flagellin epitope flg22. To gain further insight into how PFLP intensifies PTI, flg22 was used as an elicitor in Arabidopsis thaliana. First, PFLP was confirmed to intensify the rapid generation of H2O2, callose deposition, and the hypersensitive response when coinfiltrated with flg22. This response correlated with increased expression of the FLG22-induced receptor kinase 1 gene, which is part of the mitogen-activated protein kinase (MAPK) pathway. Although the increased response to flg22 alone did not depend on the MAPK pathway genes MEKK1, MKK5, and MPK6, the protective effect of PFLP decreased when plants mutated in these genes were inoculated with Pectobacterium carotovorum subsp. carotovorum. Furthermore, expression of PR1 and PDF1.2 also increased upon treatment with flg22 in the presence of PFLP. Taken together, these results suggest that activation of the MAPK pathway contributes to the increased resistance to bacterial soft rot observed in plants treated with PFLP.


Asunto(s)
Arabidopsis/enzimología , Resistencia a la Enfermedad , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Pectobacterium carotovorum/fisiología , Enfermedades de las Plantas/inmunología , Arabidopsis/genética , Arabidopsis/inmunología , Arabidopsis/microbiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Flagelina/genética , Flagelina/metabolismo , Glucanos/metabolismo , Peróxido de Hidrógeno/metabolismo , Proteínas Quinasas Activadas por Mitógenos/genética , Enfermedades de las Plantas/microbiología
14.
Exp Cell Res ; 363(1): 65-72, 2018 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-29305962

RESUMEN

Triple-negative breast cancer (TNBC) is a subtype of cancer with aggressive behaviors (high recurrence and metastasis rate) and poor prognosis. Therefore, studying the determining factors that lead to malignant TNBCs is necessary to develop personalized therapy and improve survival rates. In this study, we first analyzed levels of chromodomain helicase DNA binding protein 4 (CHD4) in 60 TNBC patients by immunohistochemical staining. We then clarified the role of CHD4 in TNBC and non-TNBC cell lines. Our clinical data indicated that higher CHD4 expression is positively correlated with metastatic stage, tumor recurrence, and survival status. Consistent with the clinical analytical data, our in vitro data also indicated that high level of CHD4 is positively correlated with malignant behaviors in TNBC cells, such as cell motility and mortality. For further analyses, we found that E-cadherin, N-cadherin and fibronetin are involved in CHD4-mediated epithelial-mesenchymal transition (EMT). Silencing of CHD4 also increased drug sensitivity to cisplatin and PARP1 inhibitor, especially in TNBC cells. Altogether, our findings showed that CHD4 is not only a potential prognostic biomarker for TNBC patient survival, but is also a powerful candidate in the development of new anti-cancer agents in TNBC.


Asunto(s)
Cadherinas/metabolismo , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2/metabolismo , Neoplasias de la Mama Triple Negativas/metabolismo , Antineoplásicos/farmacología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Cisplatino/farmacología , Transición Epitelial-Mesenquimal/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Metástasis de la Neoplasia , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico
15.
Exp Cell Res ; 359(2): 458-465, 2017 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-28842166

RESUMEN

The Mi-2/nucleosome remodeling and deacetylase (NuRD) complex play a role in silencing gene expression. CHD4, the core component of the NuRD complex, which cooperates with histone deacetylase in reducing tumor suppressor genes (TSGs). To dissect the mechanisms underlying cancer promotion, we clarify the role of CHD4 in cyclin-dependent kinase inhibitor protein p21. Here, our data indicates that CHD4 deficiency impairs the recruitments of HDAC1 to the p21 promoter. ~ 300bp proximal promoter region is responsible for CHD4-HDAC1 axis-mediated p21 transcriptional activity. For identifying the role of anti-cancer drug response, knockdown of p21 overcomes cisplatin and poly-(ADP-ribose) polymerase (PARP) inhibitor-mediated growth suppression in CHD4-depleted cells. Consistent with in vitro data, tissue of patients and bioinformatics approach also showed positive correlation between CHD4 and p21. Overall, our findings not only identify that CHD4 deficiency preferentially impairs cell survival via increasing the level of p21, but also establishes targeting CHD4 as a potential therapeutic implication in BRCA-proficient breast cancer treatment.


Asunto(s)
Autoantígenos/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Reparación del ADN , ADN/genética , Resistencia a Antineoplásicos/genética , Regulación Neoplásica de la Expresión Génica , Histona Desacetilasa 1/genética , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2/genética , Antineoplásicos/farmacología , Autoantígenos/metabolismo , Línea Celular Tumoral , Ensamble y Desensamble de Cromatina , Cisplatino/farmacología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , ADN/metabolismo , Roturas del ADN de Doble Cadena , Bases de Datos de Proteínas , Femenino , Histona Desacetilasa 1/metabolismo , Humanos , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2/metabolismo , Poli(ADP-Ribosa) Polimerasas/genética , Poli(ADP-Ribosa) Polimerasas/metabolismo , Regiones Promotoras Genéticas , Análisis por Matrices de Proteínas , Transducción de Señal
16.
J Parallel Distrib Comput ; 76: 132-144, 2015 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-25767331

RESUMEN

A graph is chordal if every cycle of length greater than three contains an edge between non-adjacent vertices. Chordal graphs are of interest both theoretically, since they admit polynomial time solutions to a range of NP-hard graph problems, and practically, since they arise in many applications including sparse linear algebra, computer vision, and computational biology. A maximal chordal subgraph is a chordal subgraph that is not a proper subgraph of any other chordal subgraph. Existing algorithms for computing maximal chordal subgraphs depend on dynamically ordering the vertices, which is an inherently sequential process and therefore limits the algorithms' parallelizability. In this paper we explore techniques to develop a scalable parallel algorithm for extracting a maximal chordal subgraph. We demonstrate that an earlier attempt at developing a parallel algorithm may induce a non-optimal vertex ordering and is therefore not guaranteed to terminate with a maximal chordal subgraph. We then give a new algorithm that first computes and then repeatedly augments a spanning chordal subgraph. After proving that the algorithm terminates with a maximal chordal subgraph, we then demonstrate that this algorithm is more amenable to parallelization and that the parallel version also terminates with a maximal chordal subgraph. That said, the complexity of the new algorithm is higher than that of the previous parallel algorithm, although the earlier algorithm computes a chordal subgraph which is not guaranteed to be maximal. We experimented with our augmentation-based algorithm on both synthetic and real-world graphs. We provide scalability results and also explore the effect of different choices for the initial spanning chordal subgraph on both the running time and on the number of edges in the maximal chordal subgraph.

17.
J Gen Virol ; 85(Pt 10): 2755-2765, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15448336

RESUMEN

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) plays key roles in both the regulation of gene expression and the replication of the EBV genome in latently infected cells. To characterize the RNA-binding activity of EBNA-1, it was demonstrated that EBNA-1 binds efficiently to RNA homopolymers that are composed of poly(G) and weakly to those composed of poly(U). All three RGG boxes of EBNA-1 contributed additively to poly(G)-binding activity and could mediate RNA binding when attached to a heterologous protein in an RNA gel mobility-shift assay. In vitro-transcribed EBV and non-EBV RNA probes revealed that EBNA-1 bound to most RNAs examined and the affinity increased as the content of G and U increased, as demonstrated in competition assays. Among these probes, the 5' non-coding region (NCR) (nt 131-278) of hepatitis C virus RNA appeared to be the strongest competitor for EBNA-1 binding to the EBV-encoded small nuclear RNA 1 (EBER1) probe, whereas a mutant 5' NCR RNA with partially disrupted secondary structure was a weak competitor. Furthermore, the interaction of endogenous EBNA-1 and EBER1 in EBV-infected cells was demonstrated by a ribonucleoprotein immunoprecipitation assay. These results revealed that EBNA-1 is a DNA-binding protein with strong binding activity to a relatively broad spectrum of RNA and suggested an additional biological impact of EBNA-1 through its ability to bind to RNA.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Antígenos Nucleares del Virus de Epstein-Barr/metabolismo , ARN/metabolismo , Hepacivirus/genética , Pruebas de Precipitina , ARN Viral/química , ARN Viral/metabolismo , Proteínas Recombinantes/metabolismo
18.
J Biomater Sci Polym Ed ; 14(1): 27-44, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12635769

RESUMEN

Hydroxypropyl methylcellulose (HPMC)/polyacrylic acid (PAA) blended films were prepared under different conditions (i.e. temperature, solvent, and cross-linking agent). The effects of hydrogen-bonding interactions or a chemical reaction between the two-component polymers in the blended films on drug release were studied. Two model drugs were used for comparison: a water-soluble drug, dl-propranolol hydrochloride, and a lipophilic drug, ketoprofen. The H-bonding interaction of HPMC/PAA was found to be stronger in the blended films prepared from H2O than that from H2O/EtOH. However, the H-bonding effect between HPMC and PAA on drug release is indistinct. Chemical esterification of the carboxylic acid groups of PAA with the hydroxyl groups of HPMC was proposed from the solid-state NMR, ESCA, and FTIR studies when the blended films were dried at 110 degrees C. This chemical reaction also resulted in insolubilization of the blended films.


Asunto(s)
Resinas Acrílicas/síntesis química , Preparaciones de Acción Retardada/síntesis química , Portadores de Fármacos/síntesis química , Metilcelulosa/análogos & derivados , Metilcelulosa/síntesis química , Resinas Acrílicas/farmacología , Materiales Biocompatibles/síntesis química , Biodegradación Ambiental , Rastreo Diferencial de Calorimetría , Enlace de Hidrógeno , Derivados de la Hipromelosa , Cetoprofeno/administración & dosificación , Cinética , Espectroscopía de Resonancia Magnética , Metilcelulosa/farmacología , Propranolol/administración & dosificación , Espectroscopía Infrarroja por Transformada de Fourier
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