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1.
Arch Biochem Biophys ; 751: 109846, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38056686

RESUMO

Plasma-activated medium (PAM) has various biological activities including anticancer and antimicrobial. However, the effect on chemoresistance in cancer cells has not been clarified in detail. Solid cancer cells form a microenvironment in the body and acquire resistance against anticancer drugs. So far, we reported that claudin-2 (CLDN2), a component of tight junctions, suppresses the anticancer drug-induced cytotoxicity of spheroids that mimic in vivo tumors. Here, we found that the protein level of CLDN2 is downregulated by the sublethal concentration of PAM in human lung adenocarcinoma-derived A549 and PC-3 cells. A cycloheximide pulse-chase assay showed that PAM accelerates the degradation of CLDN2 protein. The PAM-induced reduction of CLDN2 protein was inhibited by a lysosome inhibitor, indicating PAM may enhance the lysosomal degradation of CLDN2. The paracellular permeability to doxorubicin (DXR), an anthracycline antitumor drug, was enhanced by PAM. In the spheroids, the accumulation and toxicity of DXR were enhanced by PAM. In addition, oxidative stress and the expression of nuclear factor erythroid 2-related factor 2, one of the key factors for the acquisition of chemoresistance, were attenuated by PAM. The improvement effect of PAM on chemoresistance was suppressed by the exogenous CLDN2 overexpression. These results indicate that PAM has the ability to downregulate CLDN2 expression and may become an adjuvant drug against lung adenocarcinoma.


Assuntos
Adenocarcinoma de Pulmão , Antineoplásicos , Neoplasias Pulmonares , Humanos , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Claudina-2/metabolismo , Regulação para Baixo , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Neoplasias Pulmonares/patologia , Microambiente Tumoral
2.
Toxicol Lett ; 392: 46-55, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38142011

RESUMO

Tobacco smoke contains various carcinogenic ingredients such as nicotine, acrolein, and benzopyrene; however, their effects on cancer treatment are not fully understood. Claudin-1 (CLDN1), a component of tight junctions, is involved in the increased resistance to anticancer drugs. In this study, we found that acrolein increases the mRNA and protein levels of CLDN1 in RERF-LC-AI cells derived from human lung squamous cell carcinoma (SCC). Acrolein increased the p-extracellular signal-regulated kinase (ERK) 1/2 levels without affecting the p-Akt level. The acrolein-induced elevation of CLDN1 expression was attenuated by U0126, a mitogen-activated protein kinase kinas (MEK) inhibitor. These results indicate that the activation of MEK/ERK pathway is involved in the acrolein-induced elevation of CLDN1 expression. In a spheroid model, acrolein suppressed the accumulation and toxicity of doxorubicin (DXR), which were rescued by CLDN1 silencing. The acrolein-induced effects were also observed in lung SCC-derived EBC-1 and LK-2 cells. Acrolein also increased the expression level of nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that regulates antioxidant and detoxifying genes, which were inhibited by CLDN1 silencing. In spheroid cells, the levels of reactive oxygen species were enhanced by acrolein, which was inhibited by CLDN1 silencing. Taken together, acrolein may reduce the anticancer drug-induced toxicity in human lung SCC cells mediated by high CLDN1 expression followed by the upregulation of Nrf2 signaling pathway.


Assuntos
Antineoplásicos , Carcinoma Pulmonar de Células não Pequenas , Carcinoma de Células Escamosas , Neoplasias Pulmonares , Humanos , Claudina-1/genética , Claudina-1/metabolismo , Fator 2 Relacionado a NF-E2/genética , Acroleína/toxicidade , Carcinoma Pulmonar de Células não Pequenas/genética , Antineoplásicos/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Pulmonares/patologia , Pulmão/patologia , Quinases de Proteína Quinase Ativadas por Mitógeno
3.
Neuroscience ; 533: 10-21, 2023 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-37778692

RESUMO

Previous studies by us and others have shown that RING finger protein 213 (RNF213) is associated with cerebrovascular disease and systemic vasculopathy. Indeed, Rnf213 mRNA expression is increased in cerebral ischemia reperfusion injury (CIRI). The purpose of the present study was to investigate the role of Rnf213 in CIRI. Using the middle cerebral artery occlusion (MCAO) model, we confirmed that the expression of RNF213 protein was significantly upregulated in neurons in the ischemic penumbra. Rnf213 knockout mice were successfully generated using CRISPR/Cas9 technology. According to TTC staining and Bederson neurological scale, removal of Rnf213 decreased brain infarct volume and improved neurological deficit score, although the restoration of cerebral blood flow after MCAO was similar in WT and Rnf213-/- mice. In addition, the levels of p-Akt, p-GSK-3ß, ß-catenin and Bcl-2 were significantly increased 24 h after MCAO in the ischemic penumbra of the Rnf213-/- mice compared to WT mice, indicating that Rnf213 removal may ameliorate neuronal apoptosis by regulating the Akt/GSK-3ß/ß-catenin/Bcl-2 signaling pathway. Taken together, our study reveals that Rnf213 regulates neuronal apoptosis in CIRI, therefore impacting on brain infarct volume in brain ischemia.


Assuntos
Isquemia Encefálica , Traumatismo por Reperfusão , Ratos , Camundongos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Glicogênio Sintase Quinase 3 beta , Ratos Sprague-Dawley , beta Catenina/metabolismo , Camundongos Knockout , Apoptose , Isquemia Encefálica/metabolismo , Isquemia , Traumatismo por Reperfusão/metabolismo , Infarto Encefálico , Infarto da Artéria Cerebral Média/metabolismo
4.
Bioresour Technol ; 374: 128764, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36822554

RESUMO

The system that microbial electrolysis cell coupled anaerobic digestion (termed MEC-AD) with metal organic framework-modified cathode was operated under different voltage levels (0-1.2 V) at 20 °C. The maximum methane yield increased to 0.23 ± 0.01 LCH4 g-1COD at 0.9 V, with 28% improvement compared to 0 V (0.18 ± 0.01 LCH4 g-1COD). Moreover, total volatile fatty acid and propionate accumulation decreased by 32% and 15% at 0.9 V, indicating the system has potential to alleviate acidity suppression. Acidogens and electroactive microorganisms was clearly enriched with increasing applied voltage. Specifically, the abundance of Smithella increased, which could degrade propionate to acetate. Methanosaeta was dominant, accounting for ca. 40.1%∼55.1% of the archaea community at 0.3-1.2 V. Furthermore, the system reinforced psychrophilic methanogenesis by activating important enzymes involved in related metabolism pathways. Overall, this study provides perspective on the future practical application for the regulation of psychrophilic AD in electrochemically integrated bioreactors.


Assuntos
Microbiota , Propionatos , Anaerobiose , Reatores Biológicos , Eletrólise , Metano/metabolismo , Redes e Vias Metabólicas
5.
Int J Mol Sci ; 23(24)2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36555089

RESUMO

Claudin-2 (CLDN2), a component of tight junctions, is abnormally expressed in human lung adenocarcinoma tissue. CLDN2 contributes to chemoresistance in human lung adenocarcinoma-derived A549 cells, and it may be a target for cancer therapy. Here, we found that coffee ingredients, namely caffeine and theobromine, decreased the protein level of CLDN2 in human lung adenocarcinoma-derived A549 cells. In contrast, other components, such as theophylline and chlorogenic acid, had no effect. These results indicate that the 7-methyl group in methylxanthines may play a key role in the reduction in CLDN2 expression. The caffeine-induced reduction in the CLDN2 protein was inhibited by chloroquine, a lysosome inhibitor. In a protein-stability assay using cycloheximide, CLDN2 protein levels decreased faster in caffeine-treated cells than in vehicle-treated cells. These results suggest that caffeine accelerates the lysosomal degradation of CLDN2. The accumulation and cytotoxicity of doxorubicin were dose-dependently increased, which was exaggerated by caffeine but not by theophylline in spheroids. Caffeine decreased nuclear factor-erythroid 2-related factor 2 (Nrf2) levels without affecting hypoxia-inducible factor-1α levels. Furthermore, caffeine decreased the expression of Nrf2-targeted genes. The effects of caffeine on CLDN2 expression and anticancer-drug-induced toxicity were also observed in lung adenocarcinoma RERF-LC-MS cells. We suggest that caffeine enhances doxorubicin-induced toxicity in A549 spheroids mediated by the reduction in CLDN2 and Nrf2 expression.


Assuntos
Adenocarcinoma de Pulmão , Antineoplásicos , Neoplasias Pulmonares , Humanos , Claudina-2 , Células A549 , Cafeína/farmacologia , Cafeína/uso terapêutico , Fator 2 Relacionado a NF-E2/genética , Neoplasias Pulmonares/genética , Teofilina , Adenocarcinoma de Pulmão/metabolismo , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico
6.
Front Aging Neurosci ; 14: 977604, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36172483

RESUMO

Objective: The diagnosis of neuronal intranuclear inclusion disease (NIID) is currently based on CGG repeat expansion in the 5'UTR of the NOTCH2NLC gene, or p62-positive intranuclear inclusions in skin biopsy. The purpose of this study is to explore the value of non-invasive pathological findings in urine sediment cells from NIID patients. Materials and methods: Ten patients with clinically suspected NIID were enrolled for skin biopsy and gene screening. Morning urine (500 ml) was collected from each patient, and cell sediment was obtained by centrifugation. Urine cytology, including Giemsa staining, p62 immunostaining, and electron microscopic examination, were conducted on cell sediment. Results: The main clinical symptoms of 10 patients included episodic disturbance of consciousness, cognitive impairment, tremor, limb weakness, and so on. Cerebral MRI showed that 9 patients had linear DWI high signal in the corticomedullary junction. Genetic testing found that the number of CGG repeat ranged from 96 to 158 in the NOTCH2NLC gene. Skin biopsy revealed that all patients showed p62-positive intranuclear inclusions in 18.5 ± 6.3% of the duct epithelial cells of sweat gland. In contrast, urine sediment smears revealed that only 3 patients had p62 positive intranuclear inclusions in 3.5 ± 1.2% of the sedimentary cells. Ultrastructural examinations showed that intranuclear inclusions were also identified in the cell sediment of the 3 patients. Conclusion: Urine cytology may be a new and non-invasive pathological diagnosis technique for some NIID patients, although the positive rate is not as high as that of skin biopsy, which is a sensitive and reliable pathological method for NIID.

7.
Ann Clin Transl Neurol ; 9(5): 633-643, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35297556

RESUMO

BACKGROUND: Distal hereditary motor neuropathy (dHMN) is a heterogeneous group of diseases characterized by exclusive degeneration of peripheral motor nerves, while only 20.0-47.8% of dHMN patients are genetically identified. Recently, GGC expansion in the 5'UTR of NOTCH2NLC has been associated with dHMN. Accordingly, short tandem repeat (STR) should be further explored in genetically unsolved patients with dHMN. METHODS: A total of 128 patients from 90 unrelated families were clinically diagnosed as dHMN, and underwent a comprehensively genetic screening. Skin biopsies were conducted with routine protocols. RESULTS: Most patients showed chronic distal weakness of lower limbs (121/128), while 20 patients initially had asymmetrical involvements, 14 had subclinical sensory abnormalities, 11 had pyramidal impairments, five had cerebellar disturbance, and four had hyperCKmia. The rate of genetic detection was achieved in 36.7% (33/90), and the rate increased to 46.7% (42/90) if patients with variants uncertain significance were included. The most common causative genes included chaperone-related genes (8/33, 24.2%), tRNA synthetase genes (4/33, 12.1%), and cytoskeleton-related genes (4/33, 12.1%). Additionally, two dominant inherited families were attributed to abnormal expansion of GGC repeats in the 5'UTR of NOTCH2NLC; and a patient with dHMN and cerebellar symptoms had CAG repeat expansion in the ATXN2 gene. Skin biopsy from patients with GGC expansion in NOTCH2NLC revealed typical intranuclear inclusions on histological and ultrastructural examinations. INTERPRETATIONS: This study further extends the genetic heterogeneity of dHMN. Given some dHMN patients may be associated with nucleotides repeat expansion, STR screening is necessary to perform in genetically unsolved patients.


Assuntos
Testes Genéticos , Corpos de Inclusão Intranuclear , Regiões 5' não Traduzidas , Estudos de Coortes , Humanos , Corpos de Inclusão Intranuclear/genética
8.
Brain Stimul ; 12(4): 893-900, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30876883

RESUMO

BACKGROUND: Deep brain stimulation (DBS) is a well-established surgical therapy for Parkinson's disease (PD). Intraoperative imaging (IMG), intraoperative physiology (PHY) and their combination (COMB) are the three mainstream DBS guidance methods. OBJECTIVE: To comprehensively compare the use of IMG-DBS, PHY-DBS and COMB-DBS in treating PD. METHODS: PubMed, Embase, the Cochrane Library and OpenGrey were searched to identify PD-DBS studies reporting guidance techniques published between January 1, 2010, and May 1, 2018. We quantitatively compared the therapeutic effects, surgical time, target error and complication risk and qualitatively compared the patient experience, cost and technical prospects. A meta-regression analysis was also performed. This study is registered with PROSPERO, number CRD42018105995. RESULTS: Fifty-nine cohorts were included in the main analysis. The three groups were equivalent in therapeutic effects and infection risks. IMG-DBS (p < 0.001) and COMB-DBS (p < 0.001) had a smaller target error than PHY-DBS. IMG-DBS had a shorter surgical time (p < 0.001 and p = 0.008, respectively) and a lower intracerebral hemorrhage (ICH) risk (p = 0.013 and p = 0.004, respectively) than PHY- and COMB-DBS. The use of intraoperative imaging and microelectrode recording correlated with a higher surgical accuracy (p = 0.018) and a higher risk of ICH (p = 0.049). CONCLUSIONS: The comparison of COMB-DBS and PHY-DBS showed intraoperative imaging's superiority (higher surgical accuracy), while the comparison of COMB-DBS and IMG-DBS showed physiological confirmation's inferiority (longer surgical time and higher ICH risk). Combined with previous evidence, the use of intraoperative neuroimaging techniques should become a future trend.


Assuntos
Estimulação Encefálica Profunda/métodos , Monitorização Neurofisiológica Intraoperatória/métodos , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/terapia , Vigília/fisiologia , Estimulação Encefálica Profunda/tendências , Feminino , Humanos , Monitorização Neurofisiológica Intraoperatória/tendências , Microeletrodos , Estudos Observacionais como Assunto/métodos , Doença de Parkinson/fisiopatologia , Resultado do Tratamento
9.
Neurodegener Dis ; 15(1): 1-12, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25591625

RESUMO

The reason for regeneration in the adult spinal cord during motor neuron degeneration in amyotrophic lateral sclerosis (ALS) remains largely unknown. To this end, we studied the alteration of vimentin (a neural precursor cells marker in CNS)-containing cells (VCCs) in spinal cord during different stages of ALS used C57BL/6J G93A SOD1 transgenic mice mimicking ALS. Results showed that VCCs were mostly distributed in the ependymal zone (EZ) surrounding the central canal of spinal cord in SOD1 wild type mice; a few of VCCs were sparsely distributed in other regions. However, the number of VCCs significantly increased in the spinal cord during the onset and progression stages of ALS. They were extensively distributed in the EZ, the anterior, the lateral and the posterior horn of grey matter, particularly in the posterior horn region at the progression stage. A majority of VCCs in the anterior, the lateral and the posterior horn of grey matter (outside of EZ) generated astrocytes, but no neurons, oligodendrocytes and microgliocytes. Our results suggested that there was a potential astrocyte regenerative response to motor neuron degeneration in motor neurons-degenerated regions in the adult spinal cord during the onset and progression stages of ALS-like disease. The regenerative responses in the adult spinal cord of ALS-like mice may be a potential pathway in attempting to repair the degenerated motor neurons and restore the dysfunctional neural circuitry.


Assuntos
Esclerose Lateral Amiotrófica/patologia , Astrócitos/patologia , Astrócitos/fisiologia , Regeneração/fisiologia , Medula Espinal/patologia , Superóxido Dismutase/metabolismo , Vimentina/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Animais , Diferenciação Celular/fisiologia , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Modelos Animais de Doenças , Progressão da Doença , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células-Tronco Neurais/patologia , Células-Tronco Neurais/fisiologia , Medula Espinal/metabolismo , Células-Tronco/patologia , Células-Tronco/fisiologia , Superóxido Dismutase/genética
12.
Vet Microbiol ; 161(1-2): 137-44, 2012 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22854331

RESUMO

Brucella has been considered as a non-motile, facultative intracellular pathogenic bacterium. However, the genome sequences of different Brucella species reveal the presence of the flagellar genes needed for the construction of a functional flagellum. Due to its roles in the interaction between pathogen and host, we hypothesized that some of the flagellar proteins might induce protective immune responses and these proteins will be good subunit vaccine candidates. This study was conducted to screening of protective antigens among these flagellar proteins. Firstly, according to the putative functional roles, a total of 30 flagellar genes of Brucella abortus were selected for in vitro expression. 15 of these flagellar genes were successfully expressed as his-tagged recombinant proteins in Escherichia coli ER2566. Then, these proteins were purified and used to analyze their T cell immunity induction activity by an in vitro gamma interferon (IFN-γ) assay. Five of the flagellar proteins could stimulate significantly higher levels of IFN-γ secretion in splenocytes from S19 immunized mice, indicating their T cell induction activity. Finally, immunogenicity and protection activity of these 5 flagellar proteins were evaluated in BALB/c mice. Results showed that immunization with FlgJ (BAB1_0260) or FliN (BAB2_0122) plus adjuvant could provide protection against B. abortus 544 infection. Furthermore, mice immunized with FlgJ and FliN developed a vigorous immunoglobulin G response, and in vitro stimulation of their splenocytes with immunizing proteins induced the secretion of IFN-γ. Altogether, these data suggest that flagellar proteins FlgJ and FliN are protective antigens that could produce humoral and cell-mediated responses in mice and candidates for use in future studies of vaccination against brucellosis.


Assuntos
Vacina contra Brucelose/imunologia , Brucella abortus/imunologia , Brucelose/prevenção & controle , Vacinação , Animais , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Vacina contra Brucelose/administração & dosagem , Brucelose/imunologia , Feminino , Imunidade Humoral/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/imunologia , Fatores de Tempo , Vacinas de Subunidades Antigênicas/imunologia
13.
PLoS One ; 7(2): e29552, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22383953

RESUMO

Due to drawbacks of live attenuated vaccines, much more attention has been focused on screening of Brucella protective antigens as subunit vaccine candidates. Brucella is a facultative intracellular bacterium and cell mediated immunity plays essential roles for protection against Brucella infection. Identification of Brucella antigens that present T-cell epitopes to the host could enable development of such vaccines. In this study, 45 proven or putative pathogenesis-associated factors of Brucella were selected according to currently available data. After expressed and purified, 35 proteins were qualified for analysis of their abilities to stimulate T-cell responses in vitro. Then, an in vitro gamma interferon (IFN-γ) assay was used to identify potential T-cell antigens from B. abortus. In total, 7 individual proteins that stimulated strong IFN-γ responses in splenocytes from mice immunized with B. abortus live vaccine S19 were identified. The protective efficiencies of these 7 recombinant proteins were further evaluated. Mice given BAB1_1316 (CobB) or BAB1_1688 (AsnC) plus adjuvant could provide protection against virulent B. abortus infection, similarly with the known protective antigen Cu-Zn SOD and the license vaccine S19. In addition, CobB and AsnC could induce strong antibodies responses in BALB/c mice. Altogether, the present study showed that CobB or AsnC protein could be useful antigen candidates for the development of subunit vaccines against brucellosis with adequate immunogenicity and protection efficacy.


Assuntos
Brucella abortus/metabolismo , Brucelose/prevenção & controle , Proteínas de Escherichia coli/metabolismo , Sirtuínas/metabolismo , Transativadores/metabolismo , Animais , Antígenos de Bactérias/imunologia , Vacina contra Brucelose/imunologia , Brucelose/imunologia , Feminino , Sistema Imunitário , Imunização , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/metabolismo , Baço/citologia , Superóxido Dismutase/metabolismo , Linfócitos T/metabolismo , Linfócitos T/microbiologia
14.
Vet Microbiol ; 151(3-4): 354-62, 2011 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-21530111

RESUMO

Brucellosis brings great economic burdens for developing countries. Live attenuated vaccines are the most efficient means for prevention and control of animal Brucellosis. However, the difficulties of differentiating of infection from vaccine immunization, which is essential for eradication programs, limit their applications. Therefore, the development of a vaccine that could differentiate infection from immunization will overcome the limitations and get extensive application. VjbR is a quorum sensing regulator involving in Brucella's intracellular survival. The vjbR∷Tn5 mutants have been proven effective against wild type strain challenge, implying its possibility of use in vaccine candidate development. To further evaluate this candidate gene, in the present study, the antigenicity of purified recombinant VjbR protein was analyzed. Antibodies to Brucella melitensis VjbR could be detected in sera from patients and animals with brucellosis but not in control ones, implying the potential use of this protein as a diagnostic antigen. Then a vjbR mutant of B. melitensis 16M was constructed by replacing the vjbR with kanamycin gene. The mutant showed reduced survival in macrophage and mice. Vaccination of BALB/c mice with 16MΔvjbR conferred significant protective immunity against B. melitensis strain 16M challenges, being equivalent to which induced by the license vaccine Rev.1. The vjbR deletion mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon and interleukin-10. The most importance is that, the use of vjbR mutants as vaccines in association with diagnostic tests based on the VjbR antigen would allow the serological differentiation between infected and vaccinated animals. These results suggest that 16MΔvjbR is an ideal live attenuated vaccine candidate against B. melitensis and deserves further evaluation for vaccine development.


Assuntos
Proteínas de Bactérias/imunologia , Vacina contra Brucelose/imunologia , Brucella melitensis/imunologia , Brucelose/prevenção & controle , Animais , Formação de Anticorpos , Proteínas de Bactérias/sangue , Proteínas de Bactérias/genética , Vacina contra Brucelose/genética , Brucella melitensis/genética , Brucelose/imunologia , Linhagem Celular , Feminino , Deleção de Genes , Humanos , Imunoglobulina G/imunologia , Interferon gama/imunologia , Interleucina-10/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Deleção de Sequência , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia
16.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 23(2): 257-61, 2006 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-16706342

RESUMO

The detection of R-wave of ECG is essential to the analysis of the heart rate variability (HRV). In this paper, an R-wave detection method using wavelet transform(WT) is presented in line with the principle of discrete wavelet transform(DWT) and multi-resolution technique (MRT). We made use of the special properties of dbl wavelet in time-domain, decomposed the original ECG signals into 3-level detailed signals on different frequency bands by using DWT with Mallat algorithm, and got appropriate threshold values in different high frequency bands to distinguish R-wave. It is concluded that the algorithm had significant effects on it, which is verified by MIT/BIH (Massachusetts Institute of Technology/Boston's Beth Israel Hospital) ECG Database. The results show that R-wave could be detected accurately and localized precisely by this method, even when the patient was seriously sick or the signal was disturbed by noise. Consequently the method has a quite high locating precision (its error is not more than two sampled points and about 85 percent of the points of R-wave in ECG signal are localized precisely) and the correct detection rate of R-wave is 99.8% by using wavelet transform, so this method is quite feasible.


Assuntos
Eletrocardiografia , Frequência Cardíaca/fisiologia , Processamento de Sinais Assistido por Computador , Algoritmos , Humanos
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