Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Magn Reson Med ; 84(1): 427-436, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31788856

RESUMO

PURPOSE: To develop a novel approach to monitor lung ventilation/inflammation in cystic fibrosis (CF) patients. Lung assessment in CF patients is relevant given that most patients succumb to respiratory failure. Respiratory functional tests (forced expiratory volume in the first second; FEV1 ) and inflammatory markers are used to test pulmonary ventilation/inflammation, respectively. However, FEV1 is effort dependent and might be uncomfortable for CF patients. Furthermore, inflammatory marker detection is costly and not rapid. To overcome these limitations, we propose the measurement, by means of low field nuclear magnetic resonance, of the spin-spin relaxation time (T2m ) of water hydrogens present in CF patient sputum. In CF sputum, different biological components are pathologically increased and inversely related to lung functionality. Moreover, we showed that these components alter in a dose-dependent manner the T2m in synthetic CF sputum. METHODS: Sputum samples were obtained from 42 CF subjects by voluntary expectoration; FEV1 , C-reactive protein (CRP), blood neutrophil counts together with cytokine (tumor necrosis factor alpha [TNFα], interleukin [IL]-1ß, IL-4, and vascular endothelial growth factor) quantifications were then evaluated. RESULTS: In sputum samples, we observe that T2m directly correlates (rFEV1 = 0.44; P < 10-4 ; 169 samples) with FEV1 . Moreover, T2m inversely correlates with the circulating inflammation markers CRP/neutrophil number (rCRP = -0.44, P < 10-4 ; rNC = -0.37, P < 2 * 10-4 ; 103 and 86 samples, respectively) and with the sputum inflammatory cytokines TNFα/IL-ß1 (rTNFα = -0.72, P < 10-4 ; rIL-1ß = -0.685, P < 10-4 ; 27 samples). T2m variations also correspond to FEV1 values over time in defined patients. CONCLUSION: These findings, together with the fast, reliable, and simple determination of T2m , make our approach a novel tool potentially usable in the real world of CF patients.


Assuntos
Fibrose Cística , Pneumonia , Biomarcadores , Proteína C-Reativa , Fibrose Cística/diagnóstico por imagem , Citocinas , Humanos , Inflamação , Espectroscopia de Ressonância Magnética , Escarro , Fator A de Crescimento do Endotélio Vascular
2.
Pharmaceutics ; 16(5)2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38794326

RESUMO

BACKGROUND: The identification of novel therapeutic strategies for ovarian cancer (OC), the most lethal gynecological neoplasm, is of utmost urgency. Here, we have tested the effectiveness of the compound 2c (4-hydroxy-2,6-bis(4-nitrobenzylidene)cyclohexanone 2). 2c interferes with the cysteine-dependent deubiquitinating enzyme (DUB) UCHL5, thus affecting the ubiquitin-proteasome-dependent degradation of proteins. METHODS: 2c phenotypic/molecular effects were studied in two OC 2D/3D culture models and in a mouse xenograft model. Furthermore, we propose an in silico model of 2c interaction with DUB-UCHL5. Finally, we have tested the effect of 2c conjugated to several linkers to generate 2c/derivatives usable for improved drug delivery. RESULTS: 2c effectively impairs the OC cell line and primary tumor cell viability in both 2D and 3D conditions. The effectiveness is confirmed in a xenograft mouse model of OC. We show that 2c impairs proteasome activity and triggers apoptosis, most likely by interacting with DUB-UCHL5. We also propose a mechanism for the interaction with DUB-UCHL5 via an in silico evaluation of the enzyme-inhibitor complex. 2c also reduces cell growth by down-regulating the level of the transcription factor E2F1. Eventually, 2c activity is often retained after the conjugation with linkers. CONCLUSION: Our data strongly support the potential therapeutic value of 2c/derivatives in OC.

3.
Cancers (Basel) ; 14(7)2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35406401

RESUMO

BACKGROUND: For hepatocellular carcinoma (HCC), effective therapeutic approaches are lacking. As aberrant gene methylation is a major contributor to HCC development, demethylating drugs such as 5-azacytidine (5-Aza) have been proposed. As most 5-Aza mechanisms of action are unknown, we investigated its phenotypic/molecular effects. METHODS: 5-Aza effects were examined in the human HCC cell lines JHH-6/HuH-7 and in the rat cell-line N1-S1. We also employed a xenograft mouse model (HuH-7), a zebrafish model (JHH-6), and an orthotopic syngeneic rat model (N1-S1) of HCC. RESULTS: 5-Aza downregulated cell viability/growth/migration/adhesion by upregulating miR-139-5p, which in turn downregulated ROCK2/cyclin D1/E2F1 and increased p27kip1, resulting in G1/G0 cell accumulation. Moreover, a decrease in cyclin B1 and an increase in p27kip1 led to G2/M accumulation. Finally, we observed a decrease in MMP-2 levels, a stimulator of HCC cell migration. Aza effects were confirmed in the mouse model; in the zebrafish model, we also demonstrated the downregulation of tumor neo-angiogenesis, and in the orthotopic rat model, we observed impaired N1-S1 grafting in a healthy liver. CONCLUSION: We demonstrate for the first time that 5-Aza can impair HCC development via upregulation of miR-139-5p, which in turn impairs the ROCK2/cyclin D1/E2F1/cyclin B1 pro-proliferative pathway and the ROCK2/MMP-2 pro-migratory pathway. Thus, we provide novel information about 5-Aza mechanisms of action and deepen the knowledge about the crosstalk among ROCK2/cyclin D1/E2F1/cyclin B1/p27kip1/MMP-2 in HCC.

4.
J Am Chem Soc ; 131(25): 9086-93, 2009 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-19459637

RESUMO

The emerging applications of functionalized carbon nanotubes (CNTs) in various research domains necessitate the use of many different analytical techniques to confirm their structural modifications in a fast and reliable manner. Thus far, NMR spectroscopy has not been among the main tools for characterization of organically modified carbon nanostructures. (1)H analysis is limited because the signals in these derivatives are typically weak and broad, resulting in uncertainties of a few parts per million, and because of the strong interference of residual solvent signals. To overcome these limitations, we investigated the applicability of proton NMR spectroscopy based on gradient-edited diffusion pulse sequences (1D diffusion-ordered spectroscopy, DOSY) in the characterization of CNT derivatives. In general, diffusion NMR experiments allow the separation of NMR signals of different species present in a mixture, according to their own diffusion coefficients, merging spectroscopy information with size analysis. In the present study, a selected set of CNT derivatives was synthesized and analyzed using 1D DOSY experiments by applying strong magnetic field gradients (up to 42.6 G cm(-1)). Colorimetric tests (i.e., Kaiser test) and TGA analysis support the NMR findings, which are related to isolated and/or bundled short SWNTs, on the basis of TEM and AFM characterization. The overall results show that the diffusion-based NMR spectroscopy is a fast and promising approach for the characterization of covalently modified CNT derivatives.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Nanotubos de Carbono/análise , Difusão , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Oxirredução , Propriedades de Superfície
5.
Nat Prod Commun ; 6(4): 555-72, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21560767

RESUMO

Hyaluronan (hyaluronic acid) is a naturally occurring polysaccharide of a linear repeating disaccharide unit consisting of beta-(1-->4)-linked D-glucopyranuronic acid and beta-(1-->3)-linked 2-acetamido-2-deoxy-D-glucopyranose, which is present in extracellular matrices, the synovial fluid of joints, and scaffolding that comprises cartilage. In its mechanism of synthesis, its size, and its physico-chemical properties, hyaluronan is unique amongst other glycosaminoglycans. The network-forming, viscoelastic and its charge characteristics are important to many biochemical properties of living tissues. It is an important pericellular and cell surface constituent; its interaction with other macromolecules such as proteins, participates in regulating cell behavior during numerous morphogenic, restorative, and pathological processes in the body. The knowledge of HA in diseases such as various forms of cancers, arthritis and osteoporosis has led to new impetus in research and development in the preparation of biomaterials for surgical implants and drug conjugates for targeted delivery. A concise and focused review on hyaluronan is timely. This review will cover the following important aspects of hyaluronan: (i) biological functions and synthesis in nature; (ii) current industrial production and potential biosynthetic processes of hyaluronan; (iii) chemical modifications of hyaluronan leading to products of commercial significance; and (iv) and the global market position and manufacturers of hyaluronan.


Assuntos
Biomimética , Ácido Hialurônico/biossíntese , Ácido Hialurônico/síntese química , Ácido Hialurônico/química , Ácido Hialurônico/fisiologia , Indústrias
6.
Nat Prod Commun ; 6(5): 593-6, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21615014

RESUMO

The purpose of the present study was to isolate and characterize ailanthone-rich materials from the bark of the deciduous tree Ailanthus altissima (Mill.) Swingle and to assess their herbicide activity on selected herbaceous species. Ailanthone-rich fractions were obtained from A. altissima bark by extraction with dichloromethane and ethyl acetate and subsequent purification of these crude extracts, and of the remaining water mixture after solvent extraction, by means of gel permeation chromatography. A number of fractions were isolated and characterized for ailanthone content. A dichloromethane fraction was shown to contain 92% w/w of ailanthone, as demonstrated by HPLC and NMR analysis. A significant pre-emergence herbicide activity was found for most of the extracts which was directly correlated to ailanthone concentration. A remarkable combined pre- and post-emergence herbicide activity was found for a specific fraction. These results indicate that the bark of A. altissima may represent an interesting source for the production of natural herbicides for use in agriculture.


Assuntos
Ailanthus/química , Herbicidas/análise , Amaranthus , Chenopodium , Festuca , Extratos Vegetais/química , Quassinas/isolamento & purificação
7.
ACS Nano ; 4(4): 2051-8, 2010 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-20359236

RESUMO

Functionalized carbon nanotube (CNT) derivatives are currently under thorough investigation in different biomedical investigations. In this field of research, the composition of sample either in terms of covalently attached or physisorbed moieties can greatly affect the observed results and hamper the comparison between different studies. Therefore, the availability of a fast and reliable analytical technique to assess both the type of interaction (covalent vs noncovalent) and the composition of CNT conjugates is of great importance. Here we describe that the two-dimensional diffusion-ordered (DOSY) NMR spectroscopy is extremely useful to discriminate between conjugated and unconjugated polyethylene glycol groups in samples obtained by condensation with oxidized single-walled carbon nanotubes (SWNTs). This fast and nondestructive technique allows us to follow the removal of unconjugated polyethylene glycol chains during the purification. In particular, DOSY analysis reveal that about 1/3 (wt %) of the polyethylene glycol used for the condensation remained physisorbed to functionalized SWNTs after dialysis. Complete elimination of physisorbed polyethylene glycol was achieved using diafiltration.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Nanotubos de Carbono/química , Difusão , Polietilenoglicóis/química , Solubilidade , Temperatura , Água/química
8.
Carbohydr Res ; 344(1): 98-104, 2009 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-18950752

RESUMO

A novel methodology for making drug conjugates using hyaluronan as a carrier was developed. This strategy involves a completely regioselective two-step synthesis of 6-amino-6-deoxyhyaluronan, which is then easily functionalized with drugs through a suitable linker. The case of hyaluronan-camptothecin conjugates is described, making use of a simple succinate linker. The antitumor activity of new hyaluronan derivatives prepared is at present under evaluation.


Assuntos
Antineoplásicos/química , Antineoplásicos/síntese química , Camptotecina/química , Ácidos Carboxílicos/química , Ácido Hialurônico/química , Estrutura Molecular , Estereoisomerismo
9.
Carbohydr Res ; 344(1): 91-7, 2009 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-18926524

RESUMO

Selective halogenation of hyaluronan and partial halogen substitution by methotrexate led to 6-chloro-6-deoxy-6-O-methotrexylhyaluronan, a potential antitumor drug. The remaining halogen could be further substituted by a second organic carboxylate, leading to mixed esters. 6-O-Acetyl-6-O-methotrexylhyaluronan and 6-O-butyryl-6-O-methotrexylhyaluronan were thus synthesized and characterized by NMR spectroscopy.


Assuntos
Portadores de Fármacos/química , Portadores de Fármacos/síntese química , Ácido Hialurônico/química , Metotrexato/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA