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











Base de dados
Intervalo de ano de publicação
1.
Heliyon ; 10(1): e23313, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38148795

RESUMO

Objective: To investigate the mechanism of the six-method massage antipyretic process (SMAP) and its influence on the body's metabolic state. Methods: The random number table method was used to divide 24 New Zealand 2-month-old rabbits with qualified basal body temperature into a control group, model group and massage group (n = 8 per group). The model group and massage groups were injected with 0.5 µg/ml lipopolysaccharide (1 ml/kg) into the auricular vein, and the control group was injected with the same amount of normal saline at the same temperature. One hour after modelling, the massage group was given SMAP (opening Tianmen, pushing Kangong, rubbing Taiyang, rubbing Erhougaogu, clearing the Tianheshui and pushing the spine). The change of anal temperature 5 h after moulding was recorded to clarify the antipyretic effect. Results: After modelling, the rectal temperature of the juvenile rabbits in the three groups increased. The rectal temperature of the model group was higher than that of the control group 5 h after modelling, and the rectal temperature of the massage group was lower than that of the model group (P < 0.05). The antipyretic mechanism is related to the regulation of the synthesis of phenylalanine, tyrosine and tryptophan, as well as the pentose phosphate pathway. Compared with the model group, the plasma interleukin (IL)-1, IL-6, interferon-gamma, toll-like receptor 4, nuclear factor κB, the mechanistic target of rapamycin complex 1, indoleamine 2,3-dioxygenase 1, aryl hydrocarbon receptor, liver aspartate transaminase (AST), alanine transaminase (ALT) and l-glutamate dehydrogenase (L-GLDH) expression in the massage group were significantly decreased (P < 0.05). Compared with the model group, the massage group had significantly reduced AST, ALT and L-GLDH expression in plasma (P < 0.05). Conclusion: The mechanism of SMAP therapy is related to regulating the expression of peripheral inflammatory factors and metabolic pathways.

2.
Chin J Cancer Res ; 35(2): 140-162, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-37180836

RESUMO

Objective: AlkB homolog 5 (ALKBH5) has been proven to be closely related to tumors. However, the role and molecular mechanism of ALKBH5 in neuroblastomas have rarely been reported. Methods: The potential functional single-nucleotide polymorphisms (SNPs) in ALKBH5 were identified by National Center for Biotechnology Information (NCBI) dbSNP screening and SNPinfo software. TaqMan probes were used for genotyping. A multiple logistic regression model was used to evaluate the effects of different SNP loci on the risk of neuroblastoma. The expression of ALKBH5 in neuroblastoma was evaluated by Western blotting and immunohistochemistry (IHC). Cell counting kit-8 (CCK-8), plate colony formation and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assays were used to evaluate cell proliferation. Wound healing and Transwell assays were used to compare cell migration and invasion. Thermodynamic modelling was performed to predict the ability of miRNAs to bind to ALKBH5 with the rs8400 G/A polymorphism. RNA sequencing, N6-methyladenosine (m6A) sequencing, m6A methylated RNA immunoprecipitation (MeRIP) and a luciferase assay were used to identify the targeting effect of ALKBH5 on SPP1. Results: ALKBH5 was highly expressed in neuroblastoma. Knocking down ALKBH5 inhibited the proliferation, migration and invasion of cancer cells. miR-186-3p negatively regulates the expression of ALKBH5, and this ability is affected by the rs8400 polymorphism. When the G nucleotide was mutated to A, the ability of miR-186-3p to bind to the 3'-UTR of ALKBH5 decreased, resulting in upregulation of ALKBH5. SPP1 is the downstream target gene of the ALKBH5 oncogene. Knocking down SPP1 partially restored the inhibitory effect of ALKBH5 downregulation on neuroblastoma. Downregulation of ALKBH5 can improve the therapeutic efficacy of carboplatin and etoposide in neuroblastoma. Conclusions: We first found that the rs8400 G>A polymorphism in the m6A demethylase-encoding gene ALKBH5 increases neuroblastoma susceptibility and determines the related mechanisms. The aberrant regulation of ALKBH5 by miR-186-3p caused by this genetic variation in ALKBH5 promotes the occurrence and development of neuroblastoma through the ALKBH5-SPP1 axis.

3.
MycoKeys ; 96: 25-56, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37252054

RESUMO

Five new wood-inhabiting fungi, Lyomycesalbopulverulentus, L.yunnanensis, Xylodondaweishanensis, X.fissuratus, and X.puerensisspp. nov., are proposed based on a combination of morphological features and molecular evidence. Lyomycesalbopulverulentus is characterized by brittle basidiomata, pruinose hymenophore with a white hymenial surface, a monomitic hyphal system with clamped generative hyphae, and ellipsoid basidiospores. Lyomycesyunnanensis is characterized by a grandinioid hymenial surface, the presence of capitate cystidia, and ellipsoid basidiospores. Xylodondaweishanensis is characterized by an odontioid hymenial surface, a monomitic hyphal system with clamped generative hyphae, and broad ellipsoid-to-subglobose basidiospores. Xylodonfissuratus is characterized by a cracking basidiomata with a grandinioid hymenial surface, and ellipsoid basidiospores. Xylodonpuerensis is characterized by a poroid hymenophore with an angular or slightly daedaleoid configuration, and ellipsoid-to-broad-ellipsoid basidiospores. Sequences of ITS and nLSU rRNA markers of the studied samples were generated and phylogenetic analyses were performed with the maximum likelihood, maximum parsimony, and Bayesian inference methods. The phylogram based on the ITS+nLSU rDNA gene regions (Fig. 1) included six genera within the families Chaetoporellaceae, Hyphodontiaceae, Hymenochaetaceae, and Schizoporaceae (Hymenochaetales)-Fasciodontia, Hastodontia, Hyphodontia, Kneifiella, Lyomyces, and Xylodon-in which the five new species were grouped into genera Lyomyces and Xylodon. The phylogenetic tree inferred from the ITS sequences highlighted that Lyomycesalbopulverulentus formed a monophyletic lineage and was then grouped closely with L.bambusinus, L.orientalis, and L.sambuci; additionally, L.yunnanensis was sister to L.niveus with strong supports. The topology, based on the ITS sequences, revealed that Xylodondaweishanensis was retrieved as a sister to X.hyphodontinus; X.fissuratus was grouped with the four taxa X.montanus, X.subclavatus, X.wenshanensis, and X.xinpingensis; and X.puerensis was clustered with X.flaviporus, X.ovisporus, X.subflaviporus, X.subtropicus, and X.taiwanianus.

4.
J Clin Invest ; 132(14)2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35700056

RESUMO

Human pluripotent stem cell-based (hPSC-based) replacement therapy holds great promise for the treatment of Parkinson's disease (PD). However, the heterogeneity of hPSC-derived donor cells and the low yield of midbrain dopaminergic (mDA) neurons after transplantation hinder its broad clinical application. Here, we have characterized the single-cell molecular landscape during mDA neuron differentiation. We found that this process recapitulated the development of multiple but adjacent fetal brain regions including the ventral midbrain, the isthmus, and the ventral hindbrain, resulting in a heterogenous donor cell population. We reconstructed the differentiation trajectory of the mDA lineage and identified calsyntenin 2 (CLSTN2) and protein tyrosine phosphatase receptor type O (PTPRO) as specific surface markers of mDA progenitors, which were predictive of mDA neuron differentiation and could facilitate high enrichment of mDA neurons (up to 80%) following progenitor cell sorting and transplantation. Marker-sorted progenitors exhibited higher therapeutic potency in correcting motor deficits of PD mice. Different marker-sorted grafts had a strikingly consistent cellular composition, in which mDA neurons were enriched, while off-target neuron types were mostly depleted, suggesting stable graft outcomes. Our study provides a better understanding of cellular heterogeneity during mDA neuron differentiation and establishes a strategy to generate highly purified donor cells to achieve stable and predictable therapeutic outcomes, raising the prospect of hPSC-based PD cell replacement therapies.


Assuntos
Doença de Parkinson , Animais , Antígenos de Diferenciação , Biomarcadores/metabolismo , Diferenciação Celular/fisiologia , Terapia Baseada em Transplante de Células e Tecidos , Neurônios Dopaminérgicos/metabolismo , Humanos , Mesencéfalo/metabolismo , Camundongos , Doença de Parkinson/metabolismo , Doença de Parkinson/terapia
5.
J Hematol Oncol ; 15(1): 13, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115038

RESUMO

RNA modification plays a crucial role in many biological functions, and its abnormal regulation is associated with the progression of cancer. Among them, N6-methyladenine (m6A) is the most abundant RNA modification. Methyltransferase-like 14 (METTL14) is the central component of the m6A methylated transferase complex, which is involved in the dynamic reversible process of m6A modification. METTL14 acts as both an oncogene and tumor suppressor gene to regulate the occurrence and development of various cancers. The abnormal m6A level induced by METTL14 is related to tumorigenesis, proliferation, metastasis, and invasion. To date, the molecular mechanism of METTL14 in various malignant tumors has not been fully studied. In this paper, we systematically summarize the latest research progress on METTL14 as a new biomarker for cancer diagnosis and its biological function in human tumors and discuss its potential clinical application. This study aims to provide new ideas for targeted therapy and improved prognoses in cancer.


Assuntos
Carcinogênese/metabolismo , Metiltransferases/metabolismo , Neoplasias/metabolismo , Adenina/análogos & derivados , Adenina/metabolismo , Animais , Carcinogênese/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Metilação , Metiltransferases/análise , Metiltransferases/genética , Neoplasias/diagnóstico , Neoplasias/genética , Prognóstico , RNA/genética , RNA/metabolismo
6.
Artigo em Inglês | MEDLINE | ID: mdl-35075366

RESUMO

Inflammatory bowel disease (IBD) is a chronic inflammatory disease with a high prevalence and canceration rate. The immune disorder is one of the recognized mechanisms. Acupuncture is widely used to treat patients with IBD. In recent years, an increasing number of studies have proven the effectiveness of acupuncture in the treatment of IBD, and some progress has been made in the mechanism. In this paper, we reviewed the studies related to acupuncture for IBD and focused on the immunomodulatory mechanism. We found that acupuncture could regulate the innate and adaptive immunity of IBD patients in many ways. Acupuncture exerts innate immunomodulatory effects by regulating intestinal epithelial barrier, toll-like receptors, NLRP3 inflammasomes, oxidative stress, and endoplasmic reticulum stress and exerts adaptive immunomodulation by regulating the balance of Th17/Treg and Th1/Th2 cells. In addition, acupuncture can also regulate intestinal flora.

7.
MycoKeys ; 83: 145-160, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34629930

RESUMO

Wood-inhabiting fungi play crucial roles as decomposers in forest ecosystems and, in this study, two new wood-inhabiting corticioid fungi, Hyphodermapuerense and H.tenuissimum spp. nov., are proposed, based on a combination of morphological features and molecular evidence. Hyphodermapuerense is characterised by effused basidiomata with smooth to floccose hymenial surface, a monomitic hyphal system with clamped generative hyphae and ellipsoid basidiospores. Hyphodermatenuissimum is characterised by resupinate basidiomata with tuberculate to minutely-grandinioid hymenial surface, septate cystidia and cylindrical to allantoid basidiospores. Sequences of ITS and nLSU rRNA markers of the studied samples were generated and phylogenetic analyses were performed with Maximum Likelihood, maximum parsimony and Bayesian Inference methods. These analyses showed that the two new species clustered into Hyphoderma, in which H.puerense grouped with H.moniliforme and H.tenuissimum formed a singleton lineage. In addition, an identification key to Chinese Hyphoderma is provided.

8.
Stem Cell Res Ther ; 12(1): 462, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34407865

RESUMO

BACKGROUND: The dual inhibitors of receptor interacting protein kinase-1 and -3 (RIP1 and RIP3) play an important role in cell death processes and inflammatory responses. White matter injury (WMI), a leading cause of neurodevelopmental disabilities in preterm infants, which is characterized by extensive myelination disturbances and demyelination. Neuroinflammation, leads to the loss and differentiation-inhibition of oligodendrocyte precursor cells (OPCs), represents a major barrier to myelin repair. Whether the novel RIP1/RIP3 dual inhibitor ZJU-37 can promote transplanted OPCs derived from human neural stem cells (hOPCs) survival, differentiation and myelination remains unclear. In this study, we investigated the effect of ZJU-37 on myelination and neurobehavioral function in a neonatal rat WMI model induced by hypoxia and ischemia. METHODS: In vivo, P3 rat pups were subjected to right common carotid artery ligation and hypoxia, and then treated with ZJU-37 or/and hOPCs, then OPCs apoptosis, myelination, glial cell and NLRP3 inflammasome activation together with cognitive outcome were evaluated at 12 weeks after transplantation. In vitro, the effect of ZJU-37 on NLRP3 inflammasome activation in astrocytes induced by oxygen-glucose deprivation (OGD) were examined by western blot and immunofluorescence. The effect of ZJU-37 on OPCs apoptosis induced by the conditioned medium from OGD-injured astrocytes (OGD-astrocyte-CM) was analyzed by flow cytometry and immunofluorescence. RESULTS: ZJU-37 combined with hOPCs more effectively decreased OPC apoptosis, promoted myelination in the corpus callosum and improved behavioral function compared to ZJU-37 or hOPCs treatment. In addition, the activation of glial cells and NLRP3 inflammasome was reduced by ZJU-37 or/and hOPCs treatment in the neonatal rat WMI model. In vitro, it was also confirmed that ZJU-37 can suppress NLRP3 inflammasome activation in astrocytes induced by OGD. Not only that, the OGD-astrocyte-CM treated with ZJU-37 obviously attenuated OPC apoptosis and dysdifferentiation caused by the OGD-astrocyte-CM. CONCLUSIONS: The novel RIP1/RIP3 dual inhibitor ZJU-37 may promote OPC survival, differentiation and myelination by inhibiting NLRP3 inflammasome activation in a neonatal rat model of WMI with hOPC graft.


Assuntos
Lesões Encefálicas , Substância Branca , Animais , Astrócitos , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Bainha de Mielina , Oligodendroglia , Ratos
9.
Front Oncol ; 11: 690641, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34367972

RESUMO

Hepatoblastoma is the most common malignant liver cancer in childhood. The etiology of hepatoblastoma remains obscure. Hepatoblastoma is closely related to genetic syndromes, hinting that hepatoblastoma is a genetic predisposition disease. However, no precise exposures or genetic events are reported to hepatoblastoma occurrence. During the past decade, significant advances have been made in the understanding of etiology leading to hepatoblastoma, and several important genetic events that appear to be important for the development and progression of this tumor have been identified. Advances in our understanding of the genetic changes that underlie hepatoblastoma may translate into better patient outcomes. Single nucleotide polymorphisms (SNPs) have been generally applied in the research of etiology's exploration, disease treatment, and prognosis assessment. Here, we reviewed and discussed the molecular epidemiology, especially SNPs progresses in hepatoblastoma, to provide references for future studies and promote the study of hepatoblastoma's etiology.

10.
Transl Pediatr ; 10(3): 579-586, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33850816

RESUMO

BACKGROUND: Glioma, also known as neuroglioma, is the most common primary tumors of the central nervous system. Many previous studies have reported associations between RAS gene polymorphisms and multiple tumors. However, the role of RAS gene polymorphisms on glioma risk has not been investigated. METHODS: We conducted a two-center case-control study to investigate whether the RAS gene polymorphisms predispose individuals to gliomas in 248 healthy controls and 191 glioma patients. RAS gene polymorphisms (rs12587 G>T, rs7973450 A>G, rs7312175 G>A in KRAS, rs2273267 A>T in NRAS) were genotyped by the TaqMan assay. The relationship between RAS gene functional single nucleotide polymorphisms (SNPs) and the risk of glioma was evaluated based on odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Individuals with KRAS rs7312175 GA genotype were more likely to develop glioma than those with GG genotype (adjusted OR =1.66, 95% CI: 1.05-2.64, P=0.030). However, the other three SNPs could not affect glioma risk. In stratified analysis of age, gender, subtypes, and clinical stages, rs7312175 GA carriers were more likely to develop glioma in the following subgroups: children less than 60 months, tumor derived from the astrocytic tumors, and clinical stages I. CONCLUSIONS: The study showed that polymorphism rs7312175 GA in the KRAS gene was associated with increased glioma susceptibility. Further investigation is warranted to confirm these findings and to better elucidate the involved biological pathways.

11.
J Fungi (Basel) ; 7(4)2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923807

RESUMO

Three new wood-inhabiting fungi, Hyphoderma crystallinum, H. membranaceum, and H. microporoides spp. nov., are proposed based on a combination of morphological features and molecular evidence. Hyphoderma crystallinum is characterized by the resupinate basidiomata with smooth hymenial surface scattering scattered nubby crystals, a monomitic hyphal system with clamped generative hyphae, and numerous encrusted cystidia present. Hyphoderma membranaceum is characterized by the resupinate basidiomata with tuberculate hymenial surface, presence of the moniliform cystidia, and ellipsoid to cylindrical basidiospores. Hyphoderma microporoides is characterized by the resupinate, cottony basidiomata distributing the scattered pinholes visible using hand lens on the hymenial surface, presence of halocystidia, and cylindrical to allantoid basidiospores. Sequences of ITS+nLSU rRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. These phylogenetic analyses showed that three new species clustered into Hyphoderma, in which H. crystallinum was sister to H. variolosum, H. membranaceum was retrieved as a sister species of H. sinense, and H. microporoides was closely grouped with H. nemorale. In addition to new species, map to show global distribution of Hyphoderma species treated in the phylogenetic tree and an identification key to Chinese Hyphoderma are provided.

12.
Stem Cells Dev ; 30(11): 587-600, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33823616

RESUMO

Oligodendrocyte precursor cells (OPCs) can differentiate into myelinating oligodendrocytes during embryonic development, thereby representing an important potential source for myelin repair or regeneration. To the best of our knowledge, there are very few OPCs from human sources (human-derived OPCs [hOPCs]). In this study, we aimed to evaluate the safety and remyelination capacity of hOPCs developed in our laboratory, transplanted into the lateral ventricles of young animals. Several acute and chronic toxicity experiments were conducted in which different doses of hOPCs were transplanted into the lateral ventricles of Sprague-Dawley rats of different ages. The toxicity, biodistribution, and tumor formation ability of the injected hOPCs were examined by evaluating the rats' vital signs, developmental indicators, neural reflexes, as well as by hematology, immunology, and pathology. In addition, the hOPCs were transplanted into the corpus callosum of the shiverer mouse to verify cell myelination efficacy. Overall, our results show that transplanted hOPCs into young mice are nontoxic to their organ function or immune system. The transplanted cells engrafted in the brain and did not appear in other organs, nor did they cause tissue proliferation or tumor formation. In terms of efficacy, the transplanted hOPCs were able to form myelin in the corpus callosum, alleviate the trembling phenotype of shiverer mice, and promote normal development. The transplantation of hOPCs is safe; they can effectively form myelin in the brain, thereby providing a theoretical basis for the future clinical transplantation of hOPCs.


Assuntos
Células Precursoras de Oligodendrócitos , Animais , Diferenciação Celular , Humanos , Camundongos , Bainha de Mielina/metabolismo , Oligodendroglia , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
13.
Stem Cells Dev ; 24(5): 610-23, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25299975

RESUMO

Mesenchymal stem cells (MSCs) show great promise in blood vessel restoration and vascularization enhancement in many therapeutic situations. Typically, the co-implantation of MSCs with vascular endothelial cells (ECs) is effective for the induction of functional vascularization in vivo, indicating its potential applications in regenerative medicine. The effects of MSCs-ECs-induced vascularization can be modeled in vitro, providing simplified models for understanding their underlying communication. In this article, a contact coculture model in vitro and an RNA-seq approach were employed to reveal the active crosstalk between MSCs and ECs within a short time period at both morphological and transcriptional levels. The RNA-seq results suggested that angiogenic genes were significantly induced upon coculture, and this prevascularization commitment might require the NF-κB signaling. NF-κB blocking and interleukin (IL) neutralization experiments demonstrated that MSCs potentially secreted IL factors including IL1ß and IL6 to modulate NF-κB signaling and downstream chemokines during coculture. Conversely, RNA-seq results indicated that the MSCs were regulated by the coculture environment to a smooth muscle commitment within this short period, which largely induced myocardin, the myogenic co-transcriptional factor. These findings demonstrate the mutual molecular mechanism of MSCs-ECs-induced prevascularization commitment in a quick response.


Assuntos
Células Endoteliais da Veia Umbilical Humana/fisiologia , Células-Tronco Mesenquimais/fisiologia , Neovascularização Fisiológica , Transcriptoma , Proteínas Angiogênicas/genética , Proteínas Angiogênicas/metabolismo , Agregação Celular , Comunicação Celular , Diferenciação Celular , Células Cultivadas , Técnicas de Cocultura , Endotélio Vascular/citologia , Perfilação da Expressão Gênica , Humanos , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , NF-kappa B/metabolismo
14.
J Bone Miner Res ; 29(7): 1575-85, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24347469

RESUMO

Chondrogenic differentiation of mesenchymal stem cells (MSCs) is regulated by many factors and signal pathways, including transcription factors such as Sox9 and microRNAs. MiR-335-5p has been previously reported to regulate osteogenic and adipogenic differentiations of MSCs, but its role in chondrogenic differentiation of MSC remains unknown. In this study, we found that miR-335-5p and its host gene Mest are co-expressed and greatly upregulated during mouse MSCs (mMSCs) chondrogenesis. Overexpression of miR-335-5p in mMSCs increased expression of chondrogenic marker genes. Molecular mechanism explorations revealed that miR-335-5p targets Daam1 and ROCK1, a set of negative regulators of Sox9; Sox9 downregulates the expression of miR-29a and 29b, both negative regulators of Mest expression, thus forming a positive loop from miR-335-5p to Sox9 to Mest/miR-335-5p. In addition, miR-335-5p targets DKK1 during mMSC chondrogenic differentiation to increase ß-catenin/TCF activity, which leads to increased level of Mest transcription. These data showed miR-335-5p positively regulates MSC chondrogenesis, and two positive feedback loops are identified for the expression of miR-335-5p and its host gene Mest during the early phase of mMSC chondrogenic differentiation.


Assuntos
Retroalimentação Fisiológica , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , Regiões 3' não Traduzidas/genética , Animais , Sequência de Bases , Diferenciação Celular/genética , Condrogênese/genética , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Regulação para Baixo/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Proteínas dos Microfilamentos/metabolismo , Dados de Sequência Molecular , Proteínas/genética , Proteínas/metabolismo , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Transdução de Sinais/genética , Transcrição Gênica , Regulação para Cima/genética , Proteínas rho de Ligação ao GTP/metabolismo , Quinases Associadas a rho/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo
15.
Electrophoresis ; 33(18): 2875-83, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23019105

RESUMO

The use of surfactant mixtures to affect both EOF and separation selectivity in electrophoresis with PDMS substrates is reported, and capacitively coupled contactless conductivity detection is introduced for EOF measurement on PDMS microchips. First, the EOF was measured for two nonionic surfactants (Tween 20 and Triton X-100), mixed ionic/nonionic surfactant systems (SDS/Tween 20 and SDS/Triton X-100), and finally for the first time, mixed zwitterionic/nonionic surfactant systems (TDAPS/Tween 20 and TDAPS/Triton X-100). EOF for the nonionic surfactants decreased with increasing surfactant concentration. The addition of SDS or TDAPS to a nonionic surfactant increased EOF. After establishing the EOF behavior, the separation of model catecholamines was explored to show the impact on separations. Similar analyte resolution with greater peak heights was achieved with mixed surfactant systems containing Tween 20 and TDAPS relative to the single surfactant system. Finally, the detection of catecholamine release from PC12 cells by stimulation with 80 mM K(+) was performed to demonstrate the usefulness of mixed surfactant systems to provide resolution of biological compounds in complex samples.


Assuntos
Dimetilpolisiloxanos/química , Eletroforese em Microchip/métodos , Tensoativos/química , Animais , Ânions/química , Catecolaminas/análise , Catecolaminas/química , Catecolaminas/metabolismo , Eletro-Osmose , Octoxinol/química , Células PC12 , Polissorbatos/química , Ratos , Reprodutibilidade dos Testes , Dodecilsulfato de Sódio/química
16.
Electrophoresis ; 33(2): 379-87, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22222982

RESUMO

The use of mixtures of ionic and zwitterionic surfactants in poly(dimethylsiloxane) (PDMS) microchips is reported. The effect of surfactant concentration on electroosmotic flow (EOF) was studied for a single anionic surfactant (sodium dodecyl sulfate, SDS), a single zwitterionic surfactant (N-tetradecylammonium-N,N-dimethyl-3-ammonio-1-propanesulfonate, TDAPS), and a mixed SDS/TDAPS surfactant system. SDS increased the EOF as reported previously while TDAPS showed an initial increase in EOF followed by a reduction at higher concentrations. When TDAPS was added to a solution containing SDS, the EOF decreased in a concentration-dependent manner. The EOF for all three surfactant systems followed expected pH trends, with increasing EOF at higher pH. The mixed surfactant system allowed tuning of the EOF across a range of pH and concentration conditions. After establishing the EOF behavior, the adsorption/desorption kinetics were measured and showed a slower adsorption/desorption rate for TDAPS than SDS. Finally, the separation and electrochemical detection of model catecholamines in buffer and reduced glutathione in red blood cell lysate using the mixed surfactant system were explored. The mixed surfactant system provided shorter analysis times and/or improved resolution when compared to the single surfactant systems.


Assuntos
Dimetilpolisiloxanos/química , Eletroforese em Microchip/instrumentação , Eletroforese em Microchip/métodos , Tensoativos/química , Adsorção , Adulto , Catecolaminas/análise , Catecolaminas/isolamento & purificação , Eletro-Osmose , Eritrócitos/química , Glutationa/sangue , Glutationa/isolamento & purificação , Humanos , Concentração de Íons de Hidrogênio , Compostos de Amônio Quaternário , Dodecilsulfato de Sódio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA