Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Adv ; 10(14): eadk0647, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38569023

RESUMO

Conjugated polymers have demonstrated promising optoelectronic properties, but their brittleness and poor mechanical characteristics have hindered their fabrication into durable fibers and textiles. Here, we report a universal approach to continuously producing highly strong, ultratough conjugated polymer fibers using a flow-enhanced crystallization (FLEX) method. These fibers exhibit one order of magnitude higher tensile strength (>200 megapascals) and toughness (>80 megajoules per cubic meter) than traditional semiconducting polymer fibers and films, outperforming many synthetic fibers, ready for scalable production. These fibers also exhibit unique strain-enhanced electronic properties and exceptional performance when used as stretchable conductors, thermoelectrics, transistors, and sensors. This work not only highlights the influence of fluid mechanical effects on the crystallization and mechanical properties of conjugated polymers but also opens up exciting possibilities for integrating these functional fibers into wearable electronics.

2.
Front Immunol ; 15: 1333850, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38487532

RESUMO

Background: Extensive-stage small-cell lung cancer (ES-SCLC) is highly malignant, with early metastasis and high recurrence. Since therapeutic options are limited, ES-SCLC has a characteristically short survival period and extremely poor prognosis. A combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic drugs can achieve promising efficacy and safety in patients with ES-SCLC as a second-line or subsequent treatment, extending survival to some extent. However, the clinical outcomes remain mostly unsatisfactory and are sometimes affected by treatment-related adverse events. Case presentation: A 57-year-old woman with ES-SCLC was administered a combination therapy of atezolizumab (a PD-L1 inhibitor) and anlotinib [an oral multi-targeted tyrosine kinase inhibitor (TKI)]. She survived for 22 months, with no disease progression during the 28 courses of therapy. Unexpectedly, despite having no history of asthma, the patient developed asthma while receiving this regimen. This is possibly related to T-cell activation and the tumor immune microenvironment, which induce allergic inflammation after PD-L1 blockade. Conclusions: This is the first report of an asthma-negative ES-SCLC patient who developed asthma after receiving atezolizumab plus anlotinib. Although this combination therapy may effectively extend survival in SCLC patients, asthmatic symptoms should be closely monitored.


Assuntos
Anticorpos Monoclonais Humanizados , Asma , Indóis , Neoplasias Pulmonares , Quinolinas , Carcinoma de Pequenas Células do Pulmão , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Pulmonares/tratamento farmacológico , Terapia Combinada , Asma/tratamento farmacológico , Inibidores de Checkpoint Imunológico/efeitos adversos , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Microambiente Tumoral
3.
Angew Chem Int Ed Engl ; 63(6): e202313260, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-37938169

RESUMO

Conjugated polymers that can efficiently transport both ionic and electronic charges have broad applications in next-generation optoelectronic, bioelectronic, and energy storage devices. To date, almost all the conjugated polymers have hydrophobic backbones, which impedes efficient ion diffusion/transport in aqueous media. Here, we design and synthesize a novel hydrophilic polymer building block, 4a-azonia-naphthalene (AN), drawing inspiration from biological systems. Because of the strong electron-withdrawing ability of AN, the AN-based polymers show typical n-type charge transport behaviors. We find that cationic aromatics exhibit strong cation-π interactions, leading to smaller π-π stacking distance, interesting ion diffusion behavior, and good morphology stability. Additionally, AN enhances the hydrophilicity and ionic-electronic coupling of the polymer, which can help to improve ion diffusion/injection speed, and operational stability of organic electrochemical transistors (OECTs). The integration of cationic building blocks will undoubtedly enrich the material library for high-performance n-type conjugated polymers.

4.
Front Med (Lausanne) ; 10: 1207534, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38264056

RESUMO

Introduction: Chlamydia psittaci infection in humans is a rare cause that mainly present as community-acquired pneumonia. Severe Chlamydia psittaci pneumonia can lead to acute respiratory distress syndrome (ARDS), septic shock, or multiple organ dysfunction with a mortality rate of 15%-20% before accurate diagnosis and targeted treatment. Metagenomic next-generation sequencing (mNGS) has an advantage in achieving early diagnosis. In the study, omadacycline implementation was described to provide a better understanding of effectiveness in severe psittacosis pneumonia with ARDS. Methods: Sixteen patients with severe psittacosis pneumonia with ARDS were selected between September 2021 and October 2022. They were diagnosed using mNGS and treated with omadacycline. Retrospective analysis of clinical manifestations, laboratory data, disease progression, diagnostic tool, treatment, and prognosis was summarized. Results: Common symptoms included fever, dyspnea, and cough. All patients developed ARDS, accompanied by septic shock (43.7%) and pulmonary embolism (43.7%). Laboratory data showed normal leucocytes, increased creatine kinase isoenzyme, and decreased albumin with liver dysfunction in most patients. All patients had increased neutrophils, C-reactive protein, procalcitonin, and D-dimer with decreased lymphocytes. Airspace consolidation, ground glass opacity, and pleural effusion were found on chest CT. mNGS results were obtained in 24-48 h to identify the diagnosis of Chlamydia psittacosis. All patients received mechanical ventilation with omadacycline treatment. Fourteen patients experienced complete recovery, while the other two patients died from multidrug-resistant bacterial infection and renal failure. Conclusion: mNGS has a significant value in the diagnosis of Chlamydia psittaci infection. Timely treatment of omadacycline can improve prognosis and provide a promising new option for the treatment of severe Chlamydia psittaci pneumonia with ARDS.

5.
Shock ; 58(1): 68-77, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35670456

RESUMO

ABSTRACT: With-No lysine Kinases (WNKs) have been newly implicated in alveolar fluid clearance (AFC). Epithelial sodium channels (ENaCs) serve a vital role in AFC. The potential protective effect of WNK4 in acute respiratory distress syndrome (ARDS), mediated by ENaC-associated AFC was investigated in the study. A model of lipopolysaccharide (LPS)-induced ARDS was established in C57BL/6 mice. WNK4, Sterile 20-related proline-alanine-rich kinase (SPAK), small interfering RNA (siRNA)-WNK4 or siRNA-SPAK were transfected into mouse lung or primary alveolar epithelial type II (ATII) cells. AFC, bronchoalveolar lavage fluid and lung histomorphology were determined. The expression of ENaC was determined to investigate the regulation of AFC by WNK4-SPAK signaling pathway. Activation of WNK4-SPAK signaling improved lung injury and survival rate, with enhanced AFC and reduced pulmonary edema via the upregulation of ENaC in ARDS. In primary rat ATII cells, gene-silencing by siRNA transfection reduced ENaC expression and the level of WNK4-associated SPAK phosphorylation. Immunoprecipitation revealed that the level of neural precursor cell-expressed developmentally downregulated gene 4 (Nedd4-2) binding to ENaC was decreased as a result of WNK4-SPAK signaling. The present study demonstrated that the WNK4/SPAK pathway improved AFC during LPS-induced ARDS, which is mainly dependent on the upregulation of ENaC with Nedd4-2-mediated ubiquitination.


Assuntos
Canais Epiteliais de Sódio , Proteínas Serina-Treonina Quinases , Síndrome do Desconforto Respiratório , Animais , Canais Epiteliais de Sódio/genética , Canais Epiteliais de Sódio/metabolismo , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , RNA Interferente Pequeno , Ratos , Síndrome do Desconforto Respiratório/induzido quimicamente , Transdução de Sinais , Regulação para Cima
6.
Nat Commun ; 13(1): 2258, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35474302

RESUMO

Organic semiconductors with high-spin ground states are fascinating because they could enable fundamental understanding on the spin-related phenomenon in light element and provide opportunities for organic magnetic and quantum materials. Although high-spin ground states have been observed in some quinoidal type small molecules or doped organic semiconductors, semiconducting polymers with high-spin at their neutral ground state are rarely reported. Here we report three high-mobility semiconducting polymers with different spin ground states. We show that polymer building blocks with small singlet-triplet energy gap (ΔES-T) could enable small ΔES-T gap and increase the diradical character in copolymers. We demonstrate that the electronic structure, spin density, and solid-state interchain interactions in the high-spin polymers are crucial for their ground states. Polymers with a triplet ground state (S = 1) could exhibit doublet (S = 1/2) behavior due to different spin distributions and solid-state interchain spin-spin interactions. Besides, these polymers showed outstanding charge transport properties with high hole/electron mobilities and can be both n- and p-doped with superior conductivities. Our results demonstrate a rational approach to obtain high-mobility semiconducting polymers with different spin ground states.

7.
Food Chem ; 386: 132753, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35367801

RESUMO

The residues of bisphenol A (BPA) in milk packaging may transfer to milk, adversely affecting the human endocrine system. Consequently, to analyse or monitor BPA, it is imperative to develop rapid and effective approaches to BPA extraction from milk and milk packing as BPA is usually present in trace levels. Herein, we developed a rapid, simple, and low-cost dispersive-membrane-solid-phase-extraction (DME) for BPA with MIL-101(Cr) mixed-matrix-membrane (MMM). The MMM had large surface area (1322.09 m2/g) and pore volume (0.65 cm3/g), possessed great extraction efficiency of BPA, and kept more than 90% extraction efficiency after 20 times of reuse. Using the developed MIL-101(Cr)-MMM-based DME coupled with HPLC-fluorescence detector, we received an adequate linearity in the range of 0.1 âˆ¼ 50 µg/L BPA and a limit of detection as low as 16 ng/L under optimized conditions. The recoveries of BPA in milk and milk bottles were from 74.2% to 110.6%, with RSDs less than 9.4%.


Assuntos
Estruturas Metalorgânicas , Leite , Animais , Compostos Benzidrílicos/análise , Cromatografia Líquida de Alta Pressão , Humanos , Estruturas Metalorgânicas/química , Leite/química , Fenóis , Extração em Fase Sólida
8.
Nat Commun ; 12(1): 5723, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34588457

RESUMO

Doping has been widely used to control the charge carrier concentration in organic semiconductors. However, in conjugated polymers, n-doping is often limited by the tradeoff between doping efficiency and charge carrier mobilities, since dopants often randomly distribute within polymers, leading to significant structural and energetic disorder. Here, we screen a large number of polymer building block combinations and explore the possibility of designing n-type conjugated polymers with good tolerance to dopant-induced disorder. We show that a carefully designed conjugated polymer with a single dominant planar backbone conformation, high torsional barrier at each dihedral angle, and zigzag backbone curvature is highly dopable and can tolerate dopant-induced disorder. With these features, the designed diketopyrrolopyrrole (DPP)-based polymer can be efficiently n-doped and exhibit high n-type electrical conductivities over 120 S cm-1, much higher than the reference polymers with similar chemical structures. This work provides a polymer design concept for highly dopable and highly conductive polymeric semiconductors.

9.
Cell Death Discov ; 7(1): 63, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782389

RESUMO

The cholinergic anti-inflammatory pathway (CAIP) is important for antagonizing inflammation and treating several diseases, including acute respiratory distress syndrome (ARDS), and is related to vagus nerve integrity. However, its underlying pathophysiological mechanism is still unclear. We hypothesized that CAIP regulates lung injury repair after ARDS through the STAT3 signaling pathway, which is an important downstream effector of α7nAchR. We enhanced CAIP activity by subjecting rats to vagus nerve stimulation (VNS), and administered the α-7 acetylcholine receptor (α7nAchR) agonist and antagonist to determine whether VNS can reduce lung injury by regulating the pulmonary inflammatory response through CAIP. After being subjected to VNS, the secretion of TNF-α and IL-1ß was decreased, while the level of IL-10 was increased in the rat model of ARDS. Moreover, VNS treatment reduced lung mRNA levels of M1 macrophage markers, while increased those of M2 macrophage markers. The expression of Caspase-1 decreased, while that of STAT3 increased in lung tissue after VNS treatment. The aforementioned effects of VNS were reversed by cutting the cervical vagus efferent branch and blocking α7nAchR. These findings suggest that VNS inhibits the ARDS inflammatory response by promoting CAIP activity. Next, we used lentivirus knockdown of STAT3 expression to explore the mechanism of VNS through CAIP on lung inflammation in ARDS model rats. VNS activates α7nAchR, increases STAT3 expression, reduces Caspase-1 expression, suppresses inflammation by inhibiting inflammatory pyroptosis and M1 to M2 macrophage transformation, which may constitute the main mechanism of VNS action in ARDS.

10.
Spectrochim Acta A Mol Biomol Spectrosc ; 233: 118177, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32151986

RESUMO

Herein we describe a simple fluorescence quenching method for the selective recognition and determination of the amino acid phenylalanine (Phe). The use of 1H NMR spectroscopy revealed that the alkaloid palmatine (PAL) can encapsulated partially into the cavity of cucurbit[7]uril (Q[7]) in aqueous solution to form a stable 1:1 host-guest inclusion complex. This host-guest complex exhibits fluorescence of moderate intensity. Interestingly, the addition of the Phe results in a dramatic quenching of the fluorescence intensity associated with the inclusion complex. By contrast, the addition of other natural amino acids resulted in no change in the fluorescence. Based on the linear relationship between the fluorescence intensity and the concentration of Phe, the detection of the concentration of Phe in aqueous solution is facile. Thus, a new fluorescence quenching method for the recognition and determination of the Phe has established herein.


Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Fenilalanina/análise , Limite de Detecção , Espectrometria de Fluorescência
11.
Anal Chim Acta ; 1104: 164-171, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32106948

RESUMO

This paper demonstrated a simple and validated fluorescence enhancing method to selectively recognize and discriminate the amino acid phenylalanine (Phe). 1H NMR spectroscopy reveal that the palmatine (PAL) can be encapsulated into the cucurbit [8]uril (Q [8]) in aqueous solution to form stable 1:2 host-guest inclusion complex PAL2@Q [8], which exhibits moderate intensity fluorescence property. Interestingly, the addition of the Phe into the inclusion complex PAL2@Q [8] leads to dramatically enhancing of the fluorescence intensity. In contrast, the addition of any other natural amino acids into the inclusion complex PAL2@Q [8] gives no fluorescence variation. Furthermore, it is easy to detect the concentration of Phe in target aqueous solution according to the linear relationship between fluorescence intensity and concentration of the Phe.


Assuntos
Alcaloides de Berberina/química , Técnicas Biossensoriais/métodos , Hidrocarbonetos Aromáticos com Pontes/química , Corantes Fluorescentes/química , Imidazóis/química , Fenilalanina/análise , Calorimetria , Soluções , Espectrometria de Fluorescência , Água/química
12.
Cell Mol Biol Lett ; 24: 35, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31160894

RESUMO

BACKGROUND: Pulmonary edema is one of the pathological characteristics of acute respiratory distress syndrome (ARDS). The epithelial sodium channel (ENaC) is thought to be the rate-limiting factor for alveolar fluid clearance (AFC) during pulmonary edema. The peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone was shown to stimulate ENaC-mediated salt absorption in the kidney. However, its role in the lung remains unclear. Here, we investigated the role of the PPARγ agonist in the lung to find out whether it can regulate AFC during acute lung injury (ALI). We also attempted to elucidate the mechanism for this. METHODS: Our ALI model was established through intratracheal instillation of lipopolysaccharide (LPS) in C57BL/6 J mice. The mice were randomly divided into 4 groups of 10. The control group underwent a sham operation and received an equal quantity of saline. The three experimental groups underwent intratracheal instillation of 5 mg/kg LPS, followed by intraperitoneal injection of 4 mg/kg rosiglitazone, 4 mg/kg rosiglitazone plus 1 mg/kg GW9662, or only equal quantity of saline. The histological morphology of the lung, the levels of TNF-α and IL-1ß in the bronchoalveolar lavage fluid (BALF), the level of AFC, and the expressions of αENaC and serum and glucocorticoid-induced kinase-1 (SGK1) were determined. Type 2 alveolar (AT II) cells were incubated with rosiglitazone (15 µM) with or without GW9662 (10 µM). The expressions of αENaC and SGK1 were determined 24 h later. RESULTS: A mouse model of ALI was successfully established. Rosiglitazone significantly ameliorated the lung injury, decreasing the TNF-α and IL-1ß levels in the BALF, enhancing AFC, and promoting the expressions of αENaC and SGK1 in ALI mice, which were abolished by the specific PPARγ blocker GW9662. In vitro, rosiglitazone increased the expressions of αENaC and SGK1. This increase was prevented by GW9662. CONCLUSIONS: Rosiglitazone ameliorated the lung injury and promoted ENaC-mediated AFC via a PPARγ/SGK1-dependent signaling pathway, alleviating pulmonary edema in a mouse model of ALI.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Líquido da Lavagem Broncoalveolar/química , Canais Epiteliais de Sódio/metabolismo , PPAR gama/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Rosiglitazona/farmacologia , Transdução de Sinais , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Animais , Modelos Animais de Doenças , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 189: 608-612, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28886507

RESUMO

A plasmon induced carrier movement enhanced mechanism of surface-enhanced Raman scattering (SERS) was investigated using a charge-transfer (CT) enhancement mechanism. Here, we designed a strategy to study SERS in Au@Cu2O nanoshell nanoparticles with different shell thicknesses. Among the plasmonically coupled nanostructures, Au spheres with Cu2O shells have been of special interest due to their ultrastrong electromagnetic fields and controllable carrier transfer properties, which are useful for SERS. Au@Cu2O nanoshell nanoparticles (NPs) with shell thicknesses of 48-56nm are synthesized that exhibit high SERS activity. This high activity originates from plasmonic-induced carrier transfer from Au@Cu2O to 4-mercaptobenzoic acid (MBA). The CT transition from the valence band (VB) of Cu2O to the second excited π-π* transition of MBA, and is of b2 electronic symmetry, which was enhanced significantly. The Herzberg-Teller selection rules were employed to predict the observed enhanced b2 symmetry modes. The system constructed in this study combines the long-range electromagnetic effect of Au NPs, localized surface plasmon resonance (LSPR) of the Au@Cu2O nanoshell, and the CT contribution to assist in understanding the SERS mechanism based on LSPR-induced carrier movement in metal/semiconductor nanocomposites.

14.
Nan Fang Yi Ke Da Xue Xue Bao ; 37(4): 494-498, 2016 Apr 20.
Artigo em Chinês | MEDLINE | ID: mdl-28446402

RESUMO

OBJECTIVE: To investigate the role of interleukin-17 (IL-17) in alveolar fluid clearance in mice with acute lung injury (ALI) and explore the possible mechanism. METHODS: Sixteen IL-17-knockout mice and 16 wild-type mice were both randomized for intratracheal instillation of PBS (control) on lipopolysaccharide (LPS) to induce ALI. Forty-eight hours after the treatments, the wet-dry ratio (W/D) of the lungs, IL-8 in the bronchoalveolar lavage fluid (BALF) and histopathological changes of the lung tissues were examined. The expressions of epithelial sodium channel α subunit (α-ENaC) was detected with Western blotting and liver kinase B1 (LKB1) was detected with immunohistochemistry. RESULTS: Compared with wild-type mice treated with LPS, IL-17 knockout mice showed significantly decreased W/D of the lungs (9.739∓3.3 vs 5.351∓0.56) and IL-8 level in the BALF (67.50∓7.33 vs 41.00∓3.16 pg/mL) following LPS challenge. Pathological examination revealed reduced alveolar edema fluid aggregations and lower lung injury score in IL-17 knockout mice with also higher expression levels of ENaC and LKB1 compared with the wild-type mice. CONCLUSION: Knocking out IL-17 in mice not only alleviates inflammation of the lung tissue following ALI but also reduces the loss of ENaC protein and promotes alveolar fluid clearance, mechanism of which is probably associated with LKB1.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Líquido da Lavagem Broncoalveolar/química , Interleucina-17/metabolismo , Proteínas Quinases Ativadas por AMP , Animais , Canais Epiteliais de Sódio/metabolismo , Técnicas de Inativação de Genes , Interleucina-17/genética , Interleucina-8/metabolismo , Lipopolissacarídeos , Pulmão/patologia , Camundongos , Proteínas Serina-Treonina Quinases/metabolismo
15.
Yi Chuan ; 29(10): 1163-6, 2007 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-17905704

RESUMO

Phosphorylation is an important protein chemical modification which plays vital roles in completion and change of protein function. There are lots of technique difficulties in this field which become the challenges of the research. In recent years, phosphorylation research has made many novel achievements profit from the breakthroughs of cross-correlation techniques. In this article, we introduce the technique development of this research field from many aspects such as detection of phosphorylated proteins, enrichment of phosphorylated proteins and peptides, improvement of biological mass spectrometry-based techniques, quantification and comparison of phosphorylated proteins and peptides.


Assuntos
Peptídeos/química , Proteínas/química , Western Blotting , Peptídeos/metabolismo , Fosforilação , Proteínas/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
Yi Chuan Xue Bao ; 30(9): 881-5, 2003 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-14577382

RESUMO

Atomic force microscopy (AFM) has many advantages in the study of biological samples, such as the convenient specimen preparation and the high resolution. In the present study, AFM was used to observe the double minute chromosomes (DMs) in mouse methotrexate-resistant cell line 3T3R500. AFM images were obtained by tapping mode, contact mode and later force mode of AFM. DMs were composed of two compact spheres connected with fibers. The number of DMs in the 3T3R500 cells increased with increasing levels of methotrexate (MTX) resistance. The data of the height and the underside diameter of the DMs were also obtained. The details of specimen preparation and scan mode selection of AFM were discussed. Our results show that AFM is a powerful method in the study of DMs.


Assuntos
Aberrações Cromossômicas , Microscopia de Força Atômica/métodos , Animais , Antimetabólitos Antineoplásicos/farmacologia , Linhagem Celular , Aberrações Cromossômicas/induzido quimicamente , Cromossomos , Cromossomos de Mamíferos/efeitos dos fármacos , Cromossomos de Mamíferos/genética , Cromossomos de Mamíferos/ultraestrutura , Relação Dose-Resposta a Droga , Metotrexato/farmacologia , Camundongos
17.
Yi Chuan Xue Bao ; 30(4): 321-4, 2003 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-12812055

RESUMO

Gene amplification is a common mechanism that contributes to the drug resistance. To explore the molecular genetic background related to the MTX resistance in the mouse MTX-resistant cells, differential PCR was used to determine the amplification and overexpression of DHFR gene. In addition, the correlations between c-myc, p53 status and dhfr amplification were studied. Amplification and overexpression of dhfr suggested its role in MTX-resistant cells. However, no amplification and overexpression of c-myc were detected. On the other hand, no alteration of p53 copy number was found. The increased mRNA level of p53 suggested the normal function of p53. These results implicated the status of c-myc and p53 had no correlation with dhfr amplification, therefore some other molecular genetic alterations may exist to permit the dhfr amplification in MTX-resistant cells.


Assuntos
Metotrexato/farmacologia , Reação em Cadeia da Polimerase/métodos , Tetra-Hidrofolato Desidrogenase/genética , Animais , Resistência a Medicamentos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína Supressora de Tumor p53/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...