Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
J Breast Imaging ; 2024 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-39304331

RESUMEN

OBJECTIVE: Our objective was to compare the efficacy of digital breast tomosynthesis (DBT) and digital mammography (DM) in breast cancer screening and their impact on long-term overall survival (OS). METHODS: The study involved 48 549 consecutive mammography examinations between 2011 and 2015 at a medical center in Taiwan, identifying 545 women who were screened and diagnosed with breast cancer. Digital mammography and DBT examinations were alternated on different days. Patients were categorized based on mammographic modality, breast density, and American Joint Committee on Cancer (AJCC) stage. To determine the long-term outcome until August 2021, survival rates were analyzed using the Kaplan-Meier (K-M) survival analysis. RESULTS: The mean age at breast cancer diagnosis was 53.2 years. Digital breast tomosynthesis examinations were significantly associated with early breast cancer (AJCC stage 0 to 2) (P = .022). The 5- and 9-year OS rates for all patients were 96.8% and 93.0%, respectively. The 5- and 9-year OS was significantly greater in the DBT group (98.4% and 96.8%) compared with the DM group (95.0% and 90.4%) (P = .030 for all). The K-M survival analysis demonstrated a significantly higher OS in the DBT group than the DM group (P = .037). Furthermore, DBT significantly improved OS in a cohort of women with stage II and III cancer (P = .032) and heterogeneously dense breasts (P = .045). CONCLUSION: Screening with DBT is associated with early breast cancer diagnosis and higher survival rates compared with DM.

2.
Langmuir ; 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39010301

RESUMEN

Hierarchical polymer structures have garnered widespread application across various fields owing to their distinct surface properties and expansive surface areas. Conventional hierarchical polymer structures, however, often lack postfabrication scalability and spatial selectivity. In this study, we propose a novel strategy to prepare light-assisted hierarchical polymer structures using azopolymers (PAzo), the breath figure method, and anodic aluminum oxide (AAO) templates. Initially, the breath figure PAzo films are prepared by dripping a PAzo chloroform solution onto glass substrates in a high-humidity environment. The AAO templates are then placed on the breath figure PAzo film. Upon ultraviolet (UV) light exposure, the azobenzene groups in the azopolymers undergo trans-cis photoisomerization. This process causes the glass transition temperature (Tg) of the PAzo to become lower than room temperature, allowing the azopolymer to enter the nanopores of the AAO templates. The hierarchical azopolymer structures are then formed by using a sodium hydroxide solution to remove the templates. Furthermore, exploring the effects of PAzo concentration and UV light exposure duration on the film morphology reveals optimized conditions for hierarchical structure formation. Additionally, the water contact angles of these polymer structures are measured. The hierarchical PAzo structures exhibit higher hydrophobicity compared with the flat PAzo films and the PAzo breath figure films. Finally, patterned breath figure films can be prepared using designed photomasks, demonstrating the method's capability for spatial selectivity.

3.
Int J Biol Macromol ; 277(Pt 2): 133901, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39038585

RESUMEN

In this study, thermo-sensitive poly(N-isopropyl acrylamide) (PNP) was polymerized with pH-sensitive poly(acrylic acid) (PAA) to prepare a PAA-b-PNP block copolymer. Above its cloud point, the block copolymer self-assembled into nanoparticles (NPs), encapsulating the anticancer drug camptothecin (CPT) in situ. Chitosan (CS) and fucoidan (Fu) further modified these NPs, forming Fu-CPT-NPs to enhance biocompatibility, drug encapsulation efficiency (EE), and loading content (LC), crucially facilitating P-selectin targeting of lung cancer cells through a drug delivery system. The EE and LC reached 82 % and 3.5 %, respectively. According to transmission electron microscope observation, these Fu-CPT-NPs had uniform spherical shapes with an average diameter of ca. 250 nm. They could maintain their stability in a pH range of 5.0-6.8. In vitro experimental results revealed that the Fu-CPT-NPs exhibited good biocompatibility and had anticancer activity after encapsulating CPT. It could deliver CPT to cancer cells by targeting P-selectin, effectively increasing cell uptake and inducing cell apoptosis. Animal study results showed that the Fu-CPT-NPs inhibited lung tumor growth by increasing tumor cell apoptosis without causing significant tissue damage related to generating reactive oxygen species in lung cancer cells. This system can effectively improve drug-delivery efficiency and treatment effects and has great potential for treating lung cancer.


Asunto(s)
Camptotecina , Quitosano , Neoplasias Pulmonares , Nanopartículas , Polisacáridos , Quitosano/química , Polisacáridos/química , Polisacáridos/farmacología , Humanos , Camptotecina/farmacología , Camptotecina/química , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Nanopartículas/química , Animales , Ratones , Apoptosis/efectos de los fármacos , Portadores de Fármacos/química , Células A549 , Línea Celular Tumoral , Resinas Acrílicas/química , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Selectina-P/metabolismo , Polímeros/química
4.
Ultrasound Med Biol ; 50(9): 1372-1380, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38897841

RESUMEN

PURPOSE: A novel nomogram incorporating artificial intelligence (AI) and clinical features for enhanced ultrasound prediction of benign and malignant breast masses. MATERIALS AND METHODS: This study analyzed 340 breast masses identified through ultrasound in 308 patients. The masses were divided into training (n = 260) and validation (n = 80) groups. The AI-based analysis employed the Samsung Ultrasound AI system (S-detect). Univariate and multivariate analyses were conducted to construct nomograms using logistic regression. The AI-Nomogram was based solely on AI results, while the ClinAI- Nomogram incorporated additional clinical factors. Both nomograms underwent internal validation with 1000 bootstrap resamples and external validation using the independent validation group. Performance was evaluated by analyzing the area under the receiver operating characteristic (ROC) curve (AUC) and calibration curves. RESULTS: The ClinAI-Nomogram, which incorporates patient age, AI-based mass size, and AI-based diagnosis, outperformed an existing AI-Nomogram in differentiating benign from malignant breast masses. The ClinAI-Nomogram surpassed the AI-Nomogram in predicting malignancy with significantly higher AUC scores in both training (0.873, 95% CI: 0.830-0.917 vs. 0.792, 95% CI: 0.748-0.836; p = 0.016) and validation phases (0.847, 95% CI: 0.763-0.932 vs. 0.770, 95% CI: 0.709-0.833; p < 0.001). Calibration curves further revealed excellent agreement between the ClinAI-Nomogram's predicted probabilities and actual observed risks of malignancy. CONCLUSION: The ClinAI- Nomogram, combining AI alongside clinical data, significantly enhanced the differentiation of benign and malignant breast masses in clinical AI-facilitated ultrasound examinations.


Asunto(s)
Inteligencia Artificial , Neoplasias de la Mama , Nomogramas , Ultrasonografía Mamaria , Humanos , Neoplasias de la Mama/diagnóstico por imagen , Femenino , Persona de Mediana Edad , Ultrasonografía Mamaria/métodos , Adulto , Anciano , Mama/diagnóstico por imagen , Diagnóstico Diferencial , Reproducibilidad de los Resultados , Adulto Joven
5.
Front Oncol ; 13: 1186858, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38074669

RESUMEN

Background: Breast cancer (BC) is one of the females' most common malignant tumors there are large individual differences in its prognosis. We intended to uncover novel useful genetic biomarkers and a risk signature for BC to aid determining clinical strategies. Methods: A combined significance (p combined) was calculated for each gene by Fisher's method based on the RNA-seq, CNV, and DNA methylation data from TCGA-BRCA. Genes with a p combined< 0.01 were subjected to univariate cox and Lasso regression, whereby an RS signature was established. The predicted performance of the RS signature would be assessed in GSE7390 and GSE20685, and emphatically analyzed in triple-negative breast cancer (TNBC) patients, while the expression of immune checkpoints and drug sensitivity were also examined. GSE176078, a single-cell dataset, was used to validate the differences in cellular composition in tumors between TNBC patients with different RS. Results: The RS signature consisted of C15orf52, C1orf228, CEL, FUZ, PAK6, and SIRPG showed good performance. It could distinguish the prognosis of patients well, even stratified by disease stages or subtypes and also showed a stronger predictive ability than traditional clinical indicators. The down-regulated expressions of many immune checkpoints, while the decreased sensitivity of many antitumor drugs was observed in TNBC patients with higher RS. The overall cells and lymphocytes composition differed between patients with different RS, which could facilitate a more personalized treatment. Conclusion: The six genes RS signature established based on multi-omics data exhibited well performance in predicting the prognosis of BC patients, regardless of disease stages or subtypes. Contributing to a more personalized treatment, our signature might benefit the outcome of BC patients.

6.
Front Oncol ; 12: 1009698, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36465397

RESUMEN

Introduction: Colorectal cancer (CRC) is one of the most prevalent cancers globally with a high mortality rate. Predicting prognosis using disease progression and cancer pathologic stage is insufficient, and a prognostic factor that can accurately evaluate patient prognosis needs to be developed. In this study, we aimed to infer a prognostic gene signature to identify a functional signature associated with the prognosis of CRC patients. Methods: First, we used univariate Cox regression, least absolute shrinkage and selection operator (lasso) regression, and multivariate Cox regression analyses to screen genes significantly associated with CRC patient prognosis, from colorectal cancer RNA sequencing data in The Cancer Genome Atlas (TCGA) database. We then calculated the risk score (RS) for each patient based on the expression of the nine candidate genes and developed a prognostic signature. Results: Based on the optimal cut-off on the receiver operating characteristic (ROC) curve, patients were separated into high- and low-risk groups, and the difference in overall survival between the two groups was examined. Patients in the low-risk group had a better overall survival rate than those in the high-risk group. The results were validated using the GSE72970, GSE39582, and GSE17536 Gene Expression Omnibus (GEO) datasets, and the same conclusions were reached. ROC curve test of the RS signature also indicated that it had excellent accuracy. The RS signature was then compared with traditional clinical factors as a prognostic indicator, and we discovered that the RS signature had superior predictive ability. Conclusion: The RS signature developed in this study has excellent predictive power for the prognosis of patients with CRC and broad applicability as a prognostic indicator for patients.

7.
Nutrients ; 14(23)2022 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-36501068

RESUMEN

Evidence suggests that the source of dietary protein may have an impact on insulin resistance, but no studies have explored it in pregnant populations. In this study, we combined a population study and an animal experiment to explore this effect. The population study was conducted with data from NHANES. Multiple linear regression was used to observe the association of protein intake with outcomes, including fasting glucose (GLU), insulin (INS), and HOMA-IR. In the animal experiment, 36 pregnant SD rats in three groups were orally administered 100% animal protein, 50% animal protein and 50% plant protein, or 100% plant protein, respectively. The intervention continued throughout the whole pregnancy. On day 19.5, maternal plasma was collected after overnight fasting, and metabolomics was performed using UPLC-MS. We found plant protein intake was negatively correlated with INS and HOMA-IR in the whole population. During the third trimester, a similar correlation was also observed. The animal experiment also presented the same result. In metabolomic analysis, changes in various metabolites and related pathways including FoxO and mTOR signaling pathways were observed. In conclusion, we found a negative association between dietary plant protein intake and maternal insulin resistance during pregnancy. Changes in some active substances and related metabolic pathways may play an important role.


Asunto(s)
Resistencia a la Insulina , Embarazo , Femenino , Ratas , Animales , Proteínas de Vegetales Comestibles , Encuestas Nutricionales , Cromatografía Liquida , Ratas Sprague-Dawley , Espectrometría de Masas en Tándem , Insulina , Glucemia/metabolismo
8.
Support Care Cancer ; 30(12): 10019-10030, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36308557

RESUMEN

PURPOSE: The study aimed to identify latent classes of demoralization and examine their associations with depression and quality of life (QOL) among patients with cancer. METHODS: Cross-sectional data from 874 patients with cancer from three tertiary hospitals in Fujian province were collected using a convenience sampling method. Demoralization, depression, and QOL were assessed using the Chinese version of the Demoralization Scale-II, Patient Health Questionnaire-9, and McGill Quality of Life Questionnaire. Latent class analysis was performed on demoralization profiles. Binary logistic regression and multiple stepwise linear regression were used to examine the identified classes' associations with depression and QOL. RESULTS: Three latent classes of demoralization were identified: the "low demoralization and emotional disturbance" class (Class 1; 49.6%); "moderate demoralization and meaninglessness" class (Class 2; 29.1%); and "high demoralization and existential despair" class (Class 3; 21.3%). The severity of depression increased and the levels of QOL decreased with the three classes of demoralization. Patients with cancer being depressed in Classes 1 and 2 were 0.128 and 0.018 times that of Class 3, respectively, whereas the magnitudes of decrease in QOL scores for Classes 2 and 3 were 0.378 and 0.629, respectively. CONCLUSION: This study revealed three heterogeneous classes of demoralization in Chinese patients with cancer and indicated that increased classes were associated with more severe depression and decreased QOL. Targeted, step-by-step psychological interventions should be developed and implemented according to the characteristics of each class of demoralization to effectively promote psychological well-being among patients with cancer.


Asunto(s)
Desmoralización , Neoplasias , Humanos , Calidad de Vida , Análisis de Clases Latentes , Depresión/epidemiología , Depresión/etiología , Depresión/psicología , Estudios Transversales , Estrés Psicológico/psicología , Neoplasias/psicología , China
9.
Clin Cardiol ; 45(9): 908-912, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35925003

RESUMEN

BACKGROUND: Lipoprotein(a) [Lp(a)] is associated with coronary atherosclerotic heart disease, aortic stenosis, stroke, and heart failure. We aimed to determine the relationship between Lp(a) and aortic dissection (AD). METHODS: Two hundred patients with AD were included in our case group. The control group consisted of 200 non-AD people who were age- (±5 years) and gender-matched to the case group. Data were collected retrospectively, including hypertension, smoking, coronary artery disease, diabetes mellitus, Lp(a), total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. The association between Lp(a) and AD was studied using univariate and multivariate logistic regression analysis. RESULTS: Patients with AD had greater median Lp(a) concentrations than non-AD people (152.50 vs. 81.75 mg/L). Lp(a) was associated with AD in a multivariate logistic regression analysis (odds ratio, 8.03; 95% confidence interval, 2.85-22.62), comparing those with Lp(a) quartile 4 with those with Lp(a) quartile 1. Stratified analysis showed that this relationship was observed in both men and women, as well as in older and younger individuals. CONCLUSIONS: High levels of Lp(a) are strongly associated with AD, independent of other cardiovascular risk factors.


Asunto(s)
Disección Aórtica , Enfermedad de la Arteria Coronaria , Anciano , Disección Aórtica/diagnóstico , Disección Aórtica/epidemiología , LDL-Colesterol , Enfermedad de la Arteria Coronaria/etiología , Femenino , Humanos , Lipoproteína(a) , Masculino , Estudios Retrospectivos , Factores de Riesgo
10.
J Virol Methods ; 307: 114564, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35671888

RESUMEN

The COVID-19 pandemic caused by SARS-CoV-2 infections has led to excess deaths worldwide. Neutralizing antibodies (nAbs) against viral spike protein acquired from natural infections or vaccinations contribute to protection against new- and re-infections. Besides neutralization, antibody-mediated cellular cytotoxicity (ADCC) and phagocytosis (ADCP) are also important for viral clearance. However, due to the lack of convenient methods, the ADCC and ADCP responses elicited by viral infections or vaccinations remain to be explored. Here, we developed cell-based assays using target cells stably expressing SARS-CoV-2 spikes and Jurkat-NFAT-CD16a/CD32a effector cells for ADCC/ADCP measurements of monoclonal antibodies and human convalescent COVID-19 plasmas (HCPs). In control samples (n = 190), the specificity was 99.5% (95%CI: 98.4-100%) and 97.4% (95%CI: 95.1-99.6%) for the ADCC and ADCP assays, respectively. Among 87 COVID-19 HCPs, 83 (sensitivity: 95.4%, 95%CI: 91.0-99.8%) and 81 (sensitivity: 93.1%, 95%CI: 87.8-98.4%) showed detectable ADCC (titer range: 7.4-1721.6) and ADCP activities (titer range: 4-523.2). Notably, both ADCC and ADCP antibody titers positively correlated with the nAb titers in HCPs. In summary, we developed new tools for quantitative ADCC and ADCP analysis against SARS-CoV-2, which may facilitate further evaluations of Fc-mediated effector functions in preventing and treating against SARS-CoV-2.


Asunto(s)
Citotoxicidad Celular Dependiente de Anticuerpos , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19 , Humanos , Inmunoensayo/métodos , Pandemias , Fagocitosis , SARS-CoV-2/química , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo
11.
Cell Rep ; 38(12): 110558, 2022 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-35303476

RESUMEN

Mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) may alter viral host tropism and affect the activities of neutralizing antibodies. Here, we investigated 153 RBD mutants and 11 globally circulating variants of concern (VOCs) and variants of interest (VOIs) (including Omicron) for their antigenic changes and cross-species tropism in cells expressing 18 ACE2 orthologs. Several RBD mutations strengthened viral infectivity in cells expressing ACE2 orthologs of non-human animals, particularly those less susceptible to the ancestral strain. The mutations surrounding amino acids (aas) 439-448 and aa 484 are more likely to cause neutralization resistance. Strikingly, enhanced cross-species infection potential in the mouse and ferret, instead of the neutralization-escape scores of the mutations, account for the positive correlation with the cumulative prevalence of mutations in humans. These findings present insights for potential drivers of circulating SARS-CoV-2 variants and provide informative parameters for tracking and forecasting spreading mutations.


Asunto(s)
COVID-19 , SARS-CoV-2 , Animales , Hurones , Humanos , Glicoproteínas de Membrana/metabolismo , Ratones , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus , Tropismo , Proteínas del Envoltorio Viral
12.
Int J Biol Macromol ; 206: 422-434, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35245573

RESUMEN

C-type lectins (CTLs) play vital roles in invertebrates' innate immunity. Six CTL-X type lectins are identified in Tribolium castaneum. However, their functions and regulating mechanisms remain elusive. Here, TcCTL12, one CTL-X, was identified and cloned from T. castaneum. Spatiotemporal expression profiling revealed that TcCTL12 highly expressed in late pupa and early adult of T. castaneum in comparison with other developmental stages, and exhibited the highest expression level in the haemolymph and central nervous system (CNS). Then, the expression of TcCTL12 was remarkably induced by the stimulation of Escherichia coli and Staphylococcus aureus. Moreover, the recombinant protein TcCTL12 could bind pathogen-associated molecular patterns (PAMPs) including LPS and PGN, and displayed agglutinative activity to both Gram-positive and Gram-negative bacteria in a calcium-dependent manner in vitro. Furthermore, RNAi of TcCTL12 caused T. castaneum pupation and eclosion defected. The abnormal pupa thinned their epidermal, and appeared the abnormal development of muscle cell compared with the control group. Additionally, depletion of TcCTL12 resulted in reducing fertility of offspring and affected their fecundity. In sum, these results indicated that TcCTL12 had extensive functions in the regulation of development in T. castaneum, in addition to the immune response. It further expanded insights into CTL functions in insects.


Asunto(s)
Tribolium , Animales , Antibacterianos/metabolismo , Bacterias Gramnegativas , Bacterias Grampositivas , Inmunidad Innata , Pupa/metabolismo , Tribolium/metabolismo
13.
J Surg Oncol ; 120(7): 1162-1168, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31556139

RESUMEN

BACKGROUND: Vascularized lymph node transfer (VLNT) is an effective surgery for extremity lymphedema. This study evaluated a lymphatic drainage device (LDD) for the drainage of accumulated fluid into the venous system. METHODS: Micropore filtering membranes with pore sizes of 5, 0.65, and 0.22 µm polyvinylidene difluoride, and 0.8 µm Nylon Net Filter were evaluated to determine the in vitro efficiency of drainage flow of an LDD. The two superior membranes were further used for the evaluation of the inflow and outflow of the LDD in vivo using 5% albumin. RESULTS: At 5 minutes, the volumes drained with 5, 0.65, and 0.22 µm polyvinylidene difluoride and 0.8 µm nylon membranes were 15.2, 2.77, 2.37, and 0.59 mL, respectively (P < .01). At 10 minutes, the collected volumes of 5 and 0.65 µm polyvinylidene difluoride were 1788 and 1051 µL (P = .3). The indocyanine green fluorescence was detected at 50 seconds for the 5 µm polyvinylidene difluoride membrane but not for the 0.65 µm membrane. CONCLUSIONS: The study successfully demonstrated the proof-of-concept of the LDD prototype that mimicked VLNT with drainage of 5% albumin into the venous system in a rat model.


Asunto(s)
Modelos Animales de Enfermedad , Drenaje/instrumentación , Drenaje/métodos , Linfedema/terapia , Animales , Diseño de Equipo , Verde de Indocianina/metabolismo , Bombas de Infusión Implantables , Masculino , Ratas , Ratas Sprague-Dawley , Recuperación de la Función
14.
Nat Commun ; 7: 11095, 2016 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-27029856

RESUMEN

Plant vacuoles serve as the primary intracellular compartments for inorganic phosphate (Pi) storage. Passage of Pi across vacuolar membranes plays a critical role in buffering the cytoplasmic Pi level against fluctuations of external Pi and metabolic activities. Here we demonstrate that the SPX-MFS proteins, designated as PHOSPHATE TRANSPORTER 5 family (PHT5), also named Vacuolar Phosphate Transporter (VPT), function as vacuolar Pi transporters. Based on (31)P-magnetic resonance spectroscopy analysis, Arabidopsis pht5;1 loss-of-function mutants accumulate less Pi and exhibit a lower vacuolar-to-cytoplasmic Pi ratio than controls. Conversely, overexpression of PHT5 leads to massive Pi sequestration into vacuoles and altered regulation of Pi starvation-responsive genes. Furthermore, we show that heterologous expression of the rice homologue OsSPX-MFS1 mediates Pi influx to yeast vacuoles. Our findings show that a group of Pi transporters in vacuolar membranes regulate cytoplasmic Pi homeostasis and are required for fitness and plant growth.


Asunto(s)
Proteínas de Arabidopsis/fisiología , Arabidopsis/metabolismo , Proteínas de Transporte de Fosfato/fisiología , Fosfatos/metabolismo , Vacuolas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transporte Biológico/genética , Homeostasis , Espectroscopía de Resonancia Magnética , Oryza/genética , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo
15.
J Neurochem ; 109(5): 1400-12, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19476551

RESUMEN

Oxidative stress and down-regulated trophic factors are involved in the pathogenesis of nigrostriatal dopamine(DA)rgic neurodegeneration in Parkinson's disease. Fibroblast growth factor 9 (FGF9) is a survival factor for various cell types; however, the effect of FGF9 on DA neurons has not been studied. The antioxidant melatonin protects DA neurons against neurotoxicity. We used MPP(+) to induce neuron death in vivo and in vitro and investigated the involvement of FGF9 in MPP(+) intoxication and melatonin protection. We found that MPP(+) in a dose- and time-dependent manner inhibited FGF9 mRNA and protein expression, and caused death in primary cortical neurons. Treating neurons in the substantia nigra and mesencephalic cell cultures with FGF9 protein inhibited the MPP(+)-induced cell death of DA neurons. Melatonin co-treatment attenuated MPP(+)-induced FGF9 down-regulation and DA neuronal apoptosis in vivo and in vitro. Co-treating DA neurons with melatonin and FGF9-neutralizing antibody prevented the protective effect of melatonin. In the absence of MPP(+), the treatment of FGF9-neutralizing antibody-induced DA neuronal apoptosis whereas FGF9 protein reduced it indicating that endogenous FGF9 is a survival factor for DA neurons. We conclude that MPP(+) down-regulates FGF9 expression to cause DA neuron death and that the prevention of FGF9 down-regulation is involved in melatonin-provided neuroprotection.


Asunto(s)
1-Metil-4-fenilpiridinio/toxicidad , Dopamina/metabolismo , Factor 9 de Crecimiento de Fibroblastos/metabolismo , Herbicidas/toxicidad , Melatonina/farmacología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Animales Recién Nacidos , Anticuerpos/farmacología , Muerte Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo/efectos de los fármacos , Ensayo de Inmunoadsorción Enzimática/métodos , Factor 9 de Crecimiento de Fibroblastos/genética , Factor 9 de Crecimiento de Fibroblastos/inmunología , Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Proteína Ácida Fibrilar de la Glía/metabolismo , Masculino , Mesencéfalo/citología , Proteínas Asociadas a Microtúbulos/metabolismo , Ratas , Ratas Wistar , Sales de Tetrazolio , Tiazoles , Factores de Tiempo , Tirosina 3-Monooxigenasa/metabolismo
16.
Nucleic Acids Res ; 31(18): 5247-55, 2003 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-12954760

RESUMEN

Onconase, a cytotoxic ribonuclease from Rana pipiens, possesses pyroglutamate (Pyr) at the N-terminus and has a substrate preference for uridine-guanine (UG). To identify residues responsible for onconase's cytotoxicity, we cloned the rpr gene from genomic DNA and expressed it in Escherichia coli BL21(DE3). The recombinant onconase with Met at the N-terminus had reduced thermostability, catalytic activity and antigenicity. Therefore, we developed two methods to produce onconase without Met. One relied on the endogeneous E.coli methionine aminopeptidase and the other relied on the cleavage of a pelB signal peptide. The Pyr1 substitutional variants maintained similar secondary structures to wild-type onconase, but with less thermostability and specific catalytic activity for the innate substrate UG. However, the non-specific catalytic activity for total RNAs varied depending on the relaxation of base specificity. Pyr1 promoted the structural integrity by forming a hydrogen bond network through Lys9 in alpha1 and Val96 in beta6, and participated in catalytic activity by hydrogen bonds to Lys9 and P(1) catalytic phosphate. Residues Thr35 and Asp67 determined B(1) base specificity, and Glu91 determined B(2) base specificity. The cytotoxicity of onconase is largely determined by structural integrity and specific catalytic activity for UG through Pyr1, rather than non-specific activity for total RNAs.


Asunto(s)
Ácido Pirrolidona Carboxílico/metabolismo , Rana pipiens/genética , Ribonucleasas/metabolismo , Animales , Catálisis , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Dicroismo Circular , Clonación Molecular , ADN/química , ADN/genética , Electroforesis en Gel de Poliacrilamida , Epítopos/química , Epítopos/genética , Epítopos/inmunología , Escherichia coli/genética , Regulación Enzimológica de la Expresión Génica , Células HeLa , Humanos , Concentración 50 Inhibidora , Células K562 , Cinética , Espectrometría de Masas , Datos de Secuencia Molecular , Mutación , Ácido Pirrolidona Carboxílico/química , Ácido Pirrolidona Carboxílico/farmacología , Rana pipiens/metabolismo , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Ribonucleasas/genética , Ribonucleasas/farmacología , Análisis de Secuencia de ADN , Especificidad por Sustrato
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...