Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
BMC Cardiovasc Disord ; 24(1): 173, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38515043

RESUMO

BACKGROUND: Recently, the impact of PM2.5 on human health has been intensively studied, especially the respiratory system. High-density lipoprotein plays a crucial role in removing excess cholesterol from cells and transporting it to the liver for excretion. However, the effects of ambient PM2.5 on high-density lipoprotein (HDL) level have not been further studied. Our research aims to investigate the potential association between ambient PM2.5 concentrations and high-density lipoprotein (HDL) levels within the middle-aged and older adults in China. METHODS: We employed data from individuals aged 45 years and above who were participants in Wave 3 of the China Health and Retirement Longitudinal Study (CHARLS). The high-quality, high-resolution PM2.5 exposure concentration data for each participant were obtained from the ChinaHighAirPollutants (CHAP) dataset, while the HDL levels were derived from blood samples collected during CHARLS Wave 3. This analysis constitutes a cross-sectional study involving a total of 12,519 participants. To investigate associations, we conducted multivariate linear regression analysis, supplemented by subgroup analysis. RESULTS: In this cross-sectional investigation, we discerned a negative association between prolonged exposure to ambient PM2.5 constituents and high-density lipoprotein (HDL) levels. The observed correlation between ambient PM2.5 and HDL levels suggests that older individuals residing in areas with elevated PM2.5 concentrations exhibit a reduction in HDL levels (Beta: -0.045; 95% CI: -0.056, -0.035; P < 0.001). Upon adjusting for age in Model I, the Beta coefficient remained consistent at -0.046 (95% CI: -0.056, -0.035; p < 0.001). This association persisted even after accounting for various potential confounding factors (Beta = -0.031, 95% CI: -0.041, -0.021, p < 0.001). CONCLUSIONS: Our study reveals a statistically significant negative correlation between sustained exposure to higher concentrations of ambient PM2.5 and high-density lipoprotein (HDL) levels among Chinese middle-aged and older individuals.


Assuntos
Poluentes Atmosféricos , Pessoa de Meia-Idade , Humanos , Idoso , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Material Particulado/efeitos adversos , Estudos Transversais , Estudos Longitudinais , Lipoproteínas HDL , China/epidemiologia
2.
J Phycol ; 59(4): 775-784, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37261838

RESUMO

Species identification of Scenedesmus-like microalgae, comprising Desmodesmus, Tetradesmus, and Scenedesmus, has been challenging due to their high morphological and genetic similarity. After developing a DNA signaturing tool for Desmodesmus identification, we built a DNA signaturing database for Tetradesmus. The DNA signaturing tool contained species-specific nucleotide sequences of Tetradesmus species or strain groups with high similarity in ITS2 sequences. To construct DNA signaturing, we collected data on ITS2 sequences, aligned the sequences, organized the data by ITS2 sequence homology, and determined signature sequences according to hemi-compensatory base changes (hCBC)/CBC data from previous studies. Four Tetradesmus species and 11 strain groups had DNA signatures. The signature sequence of the genus Tetradesmus, TTA GAG GCT TAA GCA AGG ACCC, recognized 86% (157/183) of the collected Tetradesmus strains. Phylogenetic analysis of Scenedesmus-like species revealed that the Tetradesmus species were monophyletic and closely related to each other based on branch lengths. Desmodesmus was suggested to split into two subgenera due to their genetic and morphological distinction. Scenedesmus must be analyzed along with other genera of the Scenedesmaceae family to determine their genetic relationships. Importantly, DNA signaturing was integrated into a database for identifying Scenedesmus-like species through BLAST.


Assuntos
Clorofíceas , Microalgas , Scenedesmus , Filogenia , Scenedesmus/genética , Microalgas/genética , Clorofíceas/genética , DNA
3.
PLoS One ; 18(3): e0282471, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36897845

RESUMO

Accurate PM2.5 prediction is part of the fight against air pollution that helps governments to manage environmental policy. Satellite Remote sensing aerosol optical depth (AOD) processed by The Multi-Angle Implementation of Atmospheric Correlation (MAIAC) algorithm allows us to observe the transportation of remote pollutants between regions. The paper proposes a composite neural network model, the Remote Transported Pollutants (RTP) model, for such long-range pollutant transportation that predicts more accurate local PM2.5 concentrations given such satellite data. The proposed RTP model integrates several deep learning components and learns from the heterogeneous features of various domains. We also detected remote transportation pollution events (RTPEs) at two reference sites from the AOD data. Extensive experiments using real-world data show that the proposed RTP model outperforms the base model that does not account for RTPEs by 17%-30%, 23%-26% and 18%-22% and state-of-the-art models that account for RTPEs by 12%-22%, 12%-14%, and 10%-11% at +4h to +24h, +28h to +48 hours, and +52h to +72h hours respectively.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Material Particulado/análise , Taiwan , Monitoramento Ambiental , Poluição do Ar/análise , Aerossóis/análise
4.
Artigo em Inglês | MEDLINE | ID: mdl-35410004

RESUMO

Physiologists have long regarded sweating as an effective and safe means of detoxification, and heavy metals are excreted through sweat to reduce the levels of such metals in the body. However, the body can sweat through many means. To elucidate the difference in the excretion of heavy metals among sweating methods, 12 healthy young university students were recruited as participants (6 men and 6 women). Sweat samples were collected from the participants while they were either running on a treadmill or sitting in a sauna cabinet. After they experienced continuous sweating for 20 min, a minimum of 7 mL of sweat was collected from each participant, and the concentrations of nickel (Ni), lead (Pb), copper (Cu), arsenic (As), and mercury (Hg) were analyzed. The results demonstrated that the sweating method affected the excretion of heavy metals in sweat, with the concentrations of Ni, Pb, Cu, and As being significantly higher during dynamic exercise than during sitting in the sauna (all p < 0.05). However, the concentrations of Hg were unaffected by the sweating method. This study suggests that the removal of heavy metals from the body through dynamic exercise may be more effective than removal through static exposure to a hot environment.


Assuntos
Arsênio , Mercúrio , Metais Pesados , Monitoramento Ambiental , Feminino , Humanos , Chumbo , Masculino , Metais Pesados/análise , Níquel , Suor/química , Sudorese
5.
Biomedicines ; 9(10)2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34680440

RESUMO

Cell therapy is usually defined as the treatment or prevention of human disease by supplementation with cells that have been selected, manipulated, and pharmacologically treated or altered outside the body (ex vivo). Induced pluripotent stem cells (iPSCs), with their unique characteristics of indefinite expansion in cultures and genetic modifications, represent an ideal cell source for differentiation into specialized cell types. Cell therapy has recently become one of the most promising therapeutic approaches for cancers, and different immune cell types are selected as therapeutic platforms. Natural killer (NK) cells are shown to be effective tumor cell killers and do not cause graft-vs-host disease (GVHD), making them excellent candidates for, and facilitating the development of, "off-the-shelf" cell therapies. In this review, we summarize the progress in the past decade in the advent of iPSC technology and review recent developments in gene-modified iPSC-NK cells as readily available "off-the-shelf" cellular therapies.

6.
Biomed J ; 44(6 Suppl 1): S54-S62, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-35747995

RESUMO

BACKGROUND: Internal ribosome entry sites (IRESs) allow the translation of a transcript independent of its cap structure. They are distributed in some viruses and cellular RNA. The element is applied in dual gene expression in a single vector. Although it appears the lower efficiency of IRES-mediated translation than that of cap-dependent translation, it is with the crucial needs to know the precise differences in translational efficacy between upstream cistrons (cap-dependent) and downstream cistrons (IRES-mediate, cap-independent) before applying the bicistronic vector in biomedical applications. METHODS: This study aimed to provide real examples and showed the precise differences for translational efficiency dependent upon target gene locations. We generated various bicistronic constructs with quantifiable reporter genes as upstream and downstream cistrons of the encephalomyocarditis virus (EMCV) IRES to precisely evaluate the efficacy of IRES-mediated translation in mammalian cells. RESULTS: There was no significant difference in protein production when the reporter gene was cloned as an upstream cistron. However, lower levels of protein production were obtained when the reporter gene was located downstream of the IRES. Moreover, in the presence of an upstream cistron, a markedly reduced level of protein production was observed. CONCLUSION: Our findings demonstrate the version of the EMCV IRES that is provided in many commercial vectors is relatively less efficient than cap-dependent translation and provide valuable information regarding the utilization of IRES to facilitate the expression of more than one protein from a transcript.


Assuntos
Vírus da Encefalomiocardite , Sítios Internos de Entrada Ribossomal , Iniciação Traducional da Cadeia Peptídica , Animais , Vírus da Encefalomiocardite/genética , Genes Reporter , Sítios Internos de Entrada Ribossomal/genética , Camundongos , Ribossomos/genética , Ribossomos/metabolismo
7.
Front Immunol ; 12: 736261, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35069523

RESUMO

Experimental autoimmune uveitis (EAU), a model of human uveitis, is an organ-specific, T cell-mediated autoimmune disease. Autoreactive T cells can penetrate the blood-retinal barrier, which is a physical defense composed of tight junction-linked retinal pigment epithelial (RPE) cells. RPE cells serve as antigen-presenting cells (APCs) in the eye since they express MHC class I and II and Toll-like receptors (TLRs). Although previous studies have shown that supplementation with TLR agonists exacerbates uveitis, little is known about how TLR signaling in the RPE contributes to the development of uveitis. In this study, we isolated the RPE from EAU mice, which were induced by active immunization (aEAU) or adoptive transfer of antigen-specific T cells (tEAU). The expression of TLRs on RPE was determined, and both aEAU and tEAU mice exhibited induced tlr7 expression. The TLR7 agonist R848 was shown to induce aggressive disease progression, along with significantly elevated levels of the uveopathogenic cytokine IL-17. Furthermore, not only IL-17 but also R848 appeared to enhance the inflammatory response and to impair the barrier function of the RPE, indicating that TLR7 signaling is involved in the pathogenesis of EAU by affecting the behaviors of the RPE and consequently allowing the infiltration of autoreactive T cells intraocularly. Finally, local application of shRNA against TLR7 delivered by recombinant AAV effectively inhibited disease severity and reduced IFN-γ and IL-17. Our findings highlight an immunomodulatory role of RPE TLR7 in EAU development and provide a potential therapeutic strategy for autoimmune uveitis.


Assuntos
Doenças Autoimunes/imunologia , Regulação da Expressão Gênica/imunologia , Glicoproteínas de Membrana/imunologia , Epitélio Pigmentado da Retina/imunologia , Transdução de Sinais/imunologia , Receptor 7 Toll-Like/imunologia , Uveíte/imunologia , Animais , Doenças Autoimunes/genética , Modelos Animais de Doenças , Imidazóis/farmacologia , Glicoproteínas de Membrana/agonistas , Glicoproteínas de Membrana/genética , Camundongos , Transdução de Sinais/genética , Receptor 7 Toll-Like/agonistas , Receptor 7 Toll-Like/genética , Uveíte/genética
8.
Carbohydr Polym ; 240: 116164, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32475540

RESUMO

Chitosan is suggested as no or low toxicity and biocompatible biomaterial. Digestion of chitosan to reduce molecular weight and formulate nanoparticle was generally used to improve efficiency for DNA or protein delivery. However, the toxicity of low-molecular-weight chitosan (LMWCS) towards freshwater fishes has not been well evaluated. Here, we reported the toxic mechanism of LMWCS using zebrafish (Danio rerio) liver (ZFL) cell line, zebrafish larvae, and adult fish. LMWCS rapidly induced cytotoxicity of ZFL cells and death of zebrafish. Cell membrane damaged by LMWCS reduced cell viability. Damaged membrane of epithelial cell in zebrafish larvae induced breakage of the yolk. Adult fish exhibited hypoxia before death due to multiple damages induced by LMWCS. Although the toxicity of LMWCS was revealed in zebrafish model, the toxicity was only present in pH < 7 and easy be neutralized by other negative ions. Collectively, these data improved a new understanding of LMWCS properties.


Assuntos
Materiais Biocompatíveis/toxicidade , Quitosana/toxicidade , Larva/efeitos dos fármacos , Fígado/efeitos dos fármacos , Peixe-Zebra/metabolismo , Animais , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Quitosana/análogos & derivados , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Peso Molecular , Testes de Toxicidade
9.
Artigo em Inglês | MEDLINE | ID: mdl-32408694

RESUMO

This preliminarily study was made to examine the differences in sweat excretions from human eccrine and apocrine sweat glands in dynamic exercise and heat conditions. Sweat samples were collected from six young males while they were either running on a treadmill or sitting in a sauna cabinet. Sweat samples of at least 5 mL from the eccrine (upper-back) and apocrine (armpit) sweat glands were collected during a 20-min running (or inactive overheating) period. The samples were then analyzed for urea, uric acid, and electrolyte (Na+, Cl-, and K+) excretions. The results from a two-way repeated-measures analysis of variance (ANOVA) revealed that the secretions of urea and K+ were significantly higher during running than during inactive overheating for both glands, as were Na+ secretions for the apocrine glands (all P < 0.05). Under the same sweating conditions, urea and K+ excretions from the apocrine glands were also higher than those from the eccrine glands (all P < 0.05). Significant differences were observed between the Na+ secretions of the apocrine and eccrine glands under the running condition. The effects of various sweating methods and sweat glands on Cl- secretions were nonsignificant, and little uric acid was excreted. A higher urea excretion level during running rather than in hot conditions could be attributed to an elevated metabolic rate.


Assuntos
Glândulas Apócrinas , Exercício Físico , Temperatura Alta , Suor , Glândulas Écrinas/metabolismo , Humanos , Masculino , Suor/química , Glândulas Sudoríparas , Sudorese , Adulto Jovem
10.
Free Radic Biol Med ; 146: 160-180, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31689485

RESUMO

Oxidative stress-induced damage has been proposed as a major risk factor for cardiovascular disease and is a pathogenic feature of atherosclerosis. Although autophagy was reported to have a protective effect against atherosclerosis, its mechanism for reducing oxidative stress remains un-elucidated. In this study, we have identified 4 novel autophagic compounds from traditional Chinese medicines (TCMs), which activated the AMPK mediated autophagy pathway for the recovery of mitochondrial membrane potential (MMP) to reduce the production of reactive oxygen species (ROS) in Human umbilical vein endothelial cells (HUVECs). In this study, 4 compounds (TA, PG, TB and PG1) identified from Penthorum chinense Pursh (PCP) were demonstrated for the first time to possess binding affinity to HUVECs cell membranes via cell membrane chromatography (CMC) accompanied by UHPLC-TOF-MS analysis, and the 4 identified compounds induce autophagy in HUVECs. Among the 4 autophagic activators identified from PCP, TA (Thonningianin A, Pinocembrin dihydrochalcone-7-O-[3″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-glucoside) is the major chemcial component in PCP, which possesses the most potent autophagy effect via a Ca2+/AMPK-dependent and mTOR-independent pathways. Moreover, TA efficiently reduced the level of ROS in HUVECs induced by H2O2. Additionally, the expression of pro- and cleaved-IL-1ß in the aortic artery of ApoE-KO mice were also alleviated at the transcription and post-transcription levels after the administration of TA, which might be correlated to the reduction of oxidative-stress induced inflammasome-related Nod-like receptor protein3 (NLRP3) in the aortic arteries of ApoE-KO mice. This study has pinpointed the novel autophagic role of TA in alleviating the oxidative stress of HUVECs and aortic artery of ApoE-KO mice, and provided insight into the therapeutic application of TA in treatment of atherosclerosis or other cardiovascular diseases.


Assuntos
Peróxido de Hidrogênio , Lesões do Sistema Vascular , Animais , Autofagia , Células Endoteliais da Veia Umbilical Humana , Peróxido de Hidrogênio/toxicidade , Camundongos , Estresse Oxidativo , Espécies Reativas de Oxigênio
11.
Sensors (Basel) ; 19(5)2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30871084

RESUMO

Lateral field excitation quartz crystal microbalance (LFE-QCM) can detect both the electrical properties (conductivity and permittivity) and mechanical properties (viscosity and density) of the liquid. In practical applications for detecting electrical properties, the viscosity and density of the liquid will also change. This research proposed a dual-channel LFE-QCM for reducing the influence of density and viscosity. The sensing layer of one resonant element is almost bare, and the other is covered by a metal film as a reference. Different organic solutions and NaCl solution were used to study the influence of mechanical properties and the temperature on electrical properties. The experimental results demonstrate that the dual-channel LFE-QCM is necessary for properly detecting electrical properties of the liquid.

12.
Hum Gene Ther ; 30(3): 273-285, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30079767

RESUMO

Interleukin (IL)-17 and the cells that produce it within the tumor microenvironment appear to promote tumor development and are associated with survival in cancer patients. Here we investigated the role of the IL-17/IL-17 receptor A (IL-17RA) axis in regulating melanoma progression and evaluated the therapeutic potential of blocking the IL-17/IL-17RA pathway. First, recombinant mouse IL-17 (γmIL-17) treatment significantly increased proliferation of mouse B16F10 cells and human A375 and A2058 cells. Silencing IL-17RA by small hairpin RNA (shRNA) in B16F10 cells reduced the γmIL-17-elicited cell proliferation, migration, and invasion, and significantly reduced vascular endothelial growth factor and matrix metalloproteinase production. Remarkably, knockdown of IL-17RA led to a significantly decreased capability of B16F10 cells to form tumors in vivo, similar to that in IL-17-deficient mice. Finally, local application of an adenovirus delivering a shRNA against IL-17RA mRNA not only significantly suppressed tumor development, but also enhanced antitumor immunity by increasing the interferon γ-expressing T cells and not T regulatory cells. Our results highlight the critical role of the IL-17/IL-17RA pathway in tumor progression and imply that targeting IL-17RA represents a promising therapeutic strategy.


Assuntos
Marcação de Genes , Interleucina-17/genética , Melanoma Experimental/genética , Melanoma Experimental/patologia , Receptores de Interleucina-17/genética , Transdução de Sinais/efeitos dos fármacos , Adenoviridae/genética , Animais , Ciclo Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Modelos Animais de Doenças , Marcação de Genes/métodos , Vetores Genéticos/genética , Humanos , Interleucina-17/metabolismo , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/metabolismo , Camundongos , Camundongos Knockout , Metástase Neoplásica , Interferência de RNA , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genética , Receptores de Interleucina-17/metabolismo , Carga Tumoral
13.
J Am Med Inform Assoc ; 26(3): 228-241, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30535151

RESUMO

Objective: The aim of this study was to generate synthetic electronic health records (EHRs). The generated EHR data will be more realistic than those generated using the existing medical Generative Adversarial Network (medGAN) method. Materials and Methods: We modified medGAN to obtain two synthetic data generation models-designated as medical Wasserstein GAN with gradient penalty (medWGAN) and medical boundary-seeking GAN (medBGAN)-and compared the results obtained using the three models. We used 2 databases: MIMIC-III and National Health Insurance Research Database (NHIRD), Taiwan. First, we trained the models and generated synthetic EHRs by using these three 3 models. We then analyzed and compared the models' performance by using a few statistical methods (Kolmogorov-Smirnov test, dimension-wise probability for binary data, and dimension-wise average count for count data) and 2 machine learning tasks (association rule mining and prediction). Results: We conducted a comprehensive analysis and found our models were adequately efficient for generating synthetic EHR data. The proposed models outperformed medGAN in all cases, and among the 3 models, boundary-seeking GAN (medBGAN) performed the best. Discussion: To generate realistic synthetic EHR data, the proposed models will be effective in the medical industry and related research from the viewpoint of providing better services. Moreover, they will eliminate barriers including limited access to EHR data and thus accelerate research on medical informatics. Conclusion: The proposed models can adequately learn the data distribution of real EHRs and efficiently generate realistic synthetic EHRs. The results show the superiority of our models over the existing model.


Assuntos
Registros Eletrônicos de Saúde , Redes Neurais de Computação , Conjuntos de Dados como Assunto , Estatística como Assunto
14.
Front Immunol ; 8: 1508, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29184551

RESUMO

Interleukin-4 (IL-4) has been considered as one of the tolerogenic cytokines in many autoimmune animal models and clinical settings. Despite its role in antagonizing pathogenic Th1 responses, little is known about whether IL-4 possesses functions that affect regulatory T cells (Tregs). Tregs are specialized cells responsible for the maintenance of peripheral tolerance through their immune modulatory capabilities. Interestingly, it has been suggested that IL-4 supplement at a high concentration protects responder T cells (Tresps) from Treg-mediated immune suppression. In addition, such supplement also impedes TGF-ß-induced Treg differentiation in vitro. However, these phenomena may contradict the tolerogenic role of IL-4, and the effects of IL-4 on Tregs are therefore needed to be further elucidated. In this study, we utilized IL-4 knockout (KO) mice to validate the role of IL-4 on Treg-mediated immune suppression. Although IL-4 KO and control animals harbor similar frequencies of Tregs, Tregs from IL-4 KO mice weakly suppressed autologous Tresp activation. In addition, IL-4 deprivation impaired the ability of Tregs to modulate immune response, whereas IL-4 supplementation reinforced IL-4 KO Tregs in their function in suppressing Tresps. Finally, the presence of IL-4 was associated with increased cell survival and granzyme expression of Tregs. These results suggest the essential role of IL-4 in supporting Treg-mediated immune suppression, which may benefit the development of therapeutic strategies for autoimmune diseases.

15.
J Neuroinflammation ; 14(1): 15, 2017 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-28109197

RESUMO

BACKGROUND: Microglia is responsible for neuroinflammation, which may aggravate brain injury in diseases like epilepsy. Mammalian target of rapamycin (mTOR) kinase is related to microglial activation with subsequent neuroinflammation. In the present study, rapamycin and everolimus, both as mTOR inhibitors, were investigated in models of kainic acid (KA)-induced seizure and lipopolysaccharide (LPS)-induced neuroinflammation. METHODS: In vitro, we treated BV2 cells with KA and LPS. In vivo, KA was used to induce seizures on postnatal day 25 in B6.129P-Cx3cr1tm1Litt/J mice. Rapamycin and everolimus were evaluated in their modulation of neuroinflammation detected by real-time PCR, Western blotting, and immunostaining. RESULTS: Everolimus was significantly more effective than rapamycin in inhibiting iNOS and mTOR signaling pathways in both models of neuroinflammation (LPS) and seizure (KA). Everolimus significantly attenuated the mRNA expression of iNOS by LPS and nitrite production by KA and LPS than that by rapamycin. Only everolimus attenuated the mRNA expression of mTOR by LPS and KA treatment. In the present study, we also found that the modulation of mTOR under LPS and KA treatment was not mediated by Akt pathway but was primarily mediated by ERK phosphorylation, which was more significantly attenuated by everolimus. This inhibition of ERK phosphorylation and microglial activation in the hippocampus by everolimus was also confirmed in KA-treated mice. CONCLUSIONS: Rapamycin and everolimus can block the activation of inflammation-related molecules and attenuated the microglial activation. Everolimus had better efficacy than rapamycin, possibly mediated by the inhibition of ERK phosphorylation. Taken together, mTOR inhibitor can be a potential pharmacological target of anti-inflammation and seizure treatment.


Assuntos
Everolimo/farmacologia , Imunossupressores/farmacologia , Inflamação/patologia , Convulsões/patologia , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidores , Animais , Convulsivantes/toxicidade , Ácido Caínico/toxicidade , Camundongos , Microglia/efeitos dos fármacos , Convulsões/induzido quimicamente
16.
Int J Mol Sci ; 16(11): 27371-7, 2015 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-26580611

RESUMO

Asthma is the result of chronic inflammation of the airways which subsequently results in airway hyper-responsiveness and airflow obstruction. It has been shown that an elicited expression of acidic mammalian chitinase (AMCase) may be involved in the pathogenesis of asthma. Our recent study has demonstrated that the specific suppression of elevated AMCase leads to reduced eosinophilia and Th2-mediated immune responses in an ovalbumin (OVA)-sensitized mouse model of allergic asthma. In the current study, we show that the elicited expression of AMCase in the lung tissues of both ovalbumin- and Der P2-induced allergic asthma mouse models. The effects of allergic mediated molecules on AMCase expression were evaluated by utilizing promoter assay in the lung cells. In fact, the exposure of chitin, a polymerized sugar and the fundamental component of the major allergen mite and several of the inflammatory mediators, showed significant enhancement on AMCase expression. Such obtained results contribute to the basis of developing a promising therapeutic strategy for asthma by silencing AMCase expression.


Assuntos
Asma/genética , Asma/imunologia , Quitina/farmacologia , Quitinases/genética , Alérgenos/imunologia , Animais , Antígenos de Dermatophagoides/imunologia , Proteínas de Artrópodes/imunologia , Asma/metabolismo , Linhagem Celular , Quitinases/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Genes Reporter , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Regiões Promotoras Genéticas
17.
Carbohydr Polym ; 122: 321-8, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25817675

RESUMO

The purpose of this study was to use an environmentally friendly steam explosion method to achieve α- and ß-chitin structural alterations, pore generation, and deacetylation, enhancing the degree of deacetylation (DD) in chitin and extending its applications. The samples of α- and ß-chitin possessing various moisture contents that were exploded at 9 kg/cm(2) exhibited higher DDs, lower densities, lower crystallinity and more porous structures compared to unexploded chitin. After explosion, ß-chitin exhibited a larger expansion ratio, lower crystallinity and contained a larger proportion of small-sized particles compared to α-chitin. The highest DD values of exploded α- and ß-chitin with 75% moisture content were 42.9% and 43.7%, respectively. The exploded chitin samples with lower moisture content exhibited lower DDs, densities, crystallinity indices, smaller particle sizes, and higher expansion ratios than the chitin samples with higher moisture content. The chitin samples with lower moisture content also contained larger and more numerous pores.


Assuntos
Quitina/química , Tamanho da Partícula , Vapor , Água/química , Acetilação , Quitosana/química , Explosões , Peso Molecular
18.
Int J Biol Macromol ; 69: 59-63, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24854211

RESUMO

Chitin derivatives, such as those with modified main saccharide chains and deacetylated side chains, exhibit versatile biological functions. The biomedical properties of chitin oligosaccharides depend on their degree of oligomerization. Of the chitin oligosaccharides, chitin hexamers are generally the most potent. In our recent study, N-acetylchitohexaose was obtained by digesting chitin with ASCHI61, a chitinase from Aeromonas schubertii. In this work, the factors involved in the production of chitin hexasaccharide were evaluated experimentally. Using steep map analysis and cross-analysis, the substrate concentration and reaction pH were identified as the key factors in this reaction, and the interactions between these parameters were observed. Using a response surface experimental design, we predicted that a colloidal chitin concentration of 3.4mgmL(-1) and a pH of 6.54 were the optimal conditions for producing hexaoligochitin. These conditions were verified in separate experiments, in which 38.73mmolL(-1) of N-acetylchitohexaose was obtained. The maximum amount of hexamer produced was 42.175mgL(-1), an increase of only 0.27% from the predicted value.


Assuntos
Aeromonas/enzimologia , Quitina/química , Quitinases/metabolismo , Polimerização , Quitina/metabolismo , Coloides , Concentração de Íons de Hidrogênio , Cinética , Modelos Teóricos , Temperatura
19.
Appl Biochem Biotechnol ; 172(8): 3827-34, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24682877

RESUMO

In this study, chitinase activity in an incubation broth of Aeromonas schubertii was measured using colloidal chitin azure as the substrate. More specifically, the induction of chitinases due to amendment with various carbon sources was examined. The highest chitinase activity was found following amendment with 0.5-1.0 % chitin powder, whereas the activity increased negligibly due to amendment with other carbon sources, such as glucose, GlcNAc, GlcN, sorbitol, sucrose, cellulose, or starch. The chitinase activity induced by the chitin powder was suppressed when the glucose, GlcNAc, GlcN, or starch was added simultaneously to the medium but was not suppressed by the addition of sorbitol, sucrose, or cellulose. The activity of chitinase in the crude extract was also not directly inhibited by glucose. Taken together, these findings suggest that the induction of chitinase activity depends on the acquisition of suitable carbon sources from the environment and that induction occurs at a regulatory level.


Assuntos
Aeromonas/genética , Biotecnologia/métodos , Quitinases/genética , Aeromonas/efeitos dos fármacos , Aeromonas/metabolismo , Carbono/farmacologia , Quitina/química , Quitina/metabolismo , Quitinases/antagonistas & inibidores , Quitinases/biossíntese , Quitinases/metabolismo , Indução Enzimática/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Tamanho da Partícula
20.
Int J Biol Macromol ; 62: 518-22, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24099937

RESUMO

Hexaoligochitin produced by chitinase, ASCHI61, from Aeromonas schubertii was recently expressed. In this work, the optimal conditions for the mass production of ASCHI61 were investigated. The efficiency of recombinant protein expression in Escherichia coli was determined by various parameters, including the pH of the culture medium, induction temperature, shaking speed, inducer concentration, and induction period. The optimization experiments could be simplified through a statistical design of experiments (response surface methodology). From the fractional factorial design, the interactive effect of induction temperature and time was the most significant. The total activity of the enzyme was 32,092 U at 23.9 °C with 115 min of induction. Under those conditions, the total activity of the recombinant protein was 30,650 U in the fermentation experiments, with an error of only 4.8%. The total activity of ASCHI61 increased 1.54-fold under the optimal conditions. Based on the results, ASCHI61 can be expressed more for hexaoligochitin production.


Assuntos
Quitinases/biossíntese , Fermentação , Proteínas Recombinantes/biossíntese , Técnicas de Cultura Celular por Lotes/métodos , Técnicas de Cultura Celular por Lotes/normas , Quitina/química , Quitina/metabolismo , Quitinases/metabolismo , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Reprodutibilidade dos Testes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...