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1.
Eur Radiol ; 2022 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-35420297

RESUMO

OBJECTIVES: To assess whether systemic-pulmonary collaterals are associated with clinical severity and extent of pulmonary perfusion defects in chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: This prospective study was approved by a local ethics committee. Twenty-four patients diagnosed with inoperable CTEPH were enrolled between July 2014 and February 2017. Systemic-pulmonary collaterals were detected using pulmonary vascular enhancement on intra-aortic computed tomography (CT) angiography. The pulmonary enhancement parameters were calculated, including (1) Hounsfield unit differences (HUdiff) between pulmonary trunks and pulmonary arteries (PAs) or veins (PVs), namely HUdiff-PA and HUdiff-PV, on the segmental base; (2) the mean HUdiff-PA, mean HUdiff-PV, numbers of significantly enhanced PAs and PVs, on the patient base. Pulmonary perfusion defects were recorded and scored using the lung perfused blood volume (PBV) based on intravenous dual-energy CT (DECT) angiography. Pearson's or Spearman's correlation coefficients were used to evaluate correlations between the following: (1) segment-based intra-aortic CT and intravenous DECT parameters (2) patient-based intra-aortic CT parameters and clinical severity parameters or lung PBV scores. Statistical significance was set at p < 0.05. RESULTS: Segmental HUdiff-PV was correlated with the segmental perfusion defect score (r = 0.45, p < 0.01). The mean HUdiff-PV was correlated with the mean pulmonary arterial pressure (PAP) (r = 0.52, p < 0.01), cardiac output (rho = - 0.41, p = 0.05), and lung PBV score (rho = 0.43, p = 0.04). And the number of significantly enhanced PVs was correlated with the mean PAP (r = 0.54, p < 0.01), pulmonary vascular resistance (r = 0.54, p < 0.01), and lung PBV score (rho = 0.50, p = 0.01). CONCLUSIONS: PV enhancement measured by intra-aortic CT angiography reflects clinical severity and pulmonary perfusion defects in CTEPH. KEY POINTS: • Intra-aortic CT angiography demonstrated heterogeneous enhancement within the pulmonary vasculature, showing collaterals from the systemic arteries to the pulmonary circulation in CTEPH. • The degree of systemic-pulmonary collateral development was significantly correlated with the clinical severity of CTEPH and may be used to evaluate disease progression. • The distribution of systemic-pulmonary collaterals is positively correlated with perfusion defects in the lung segments in CTEPH.

2.
J Thorac Dis ; 14(1): 76-89, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35242370

RESUMO

BACKGROUND: Although the incident rate is low, sternal dislocation and dehiscence due to unstable sternal fixation after cardiovascular surgery could cause potentially lethal complications. Thus, to enforce the stability of closed sternum, the sternal pins have been utilized at surgeon's discretion. However, there is no randomized clinical trial to test whether these pins are effective to stabilize a sternum. Hence, this study aimed to examine the clinical efficacy of bioabsorbable poly-L-lactide (PLLA) sternal pins in reinforcing sternal stability and preventing instability of the sternum after full sternotomy. METHODS: We conducted a single institutional, prospective, randomized, single-blinded clinical study involving 100 patients who underwent an initial cardiovascular surgery via sternotomy. Patients were randomly allocated into two groups: with (group P) and without (group N) PLLA sternal pins, at 1:1 ratio from November 2013 to April 2016. Sternal deviation and stability were assessed with postoperative computed tomography (CT) at two postures to put shear stress on the sternum. Additionally, information on patient demographic indices was obtained prospectively, and patient's pain intensity was assessed with numerical rating scoring system during rehabilitation. Furthermore, propensity score matching was performed for further comparative sub-analysis. RESULTS: Ninety-one patients (43 in group P and 48 in group N) were analyzed using the intention-to-treat method. Group N had a significantly higher proportion of males (P=0.015) and ischemic disease as a primary diagnosis (P=0.040) than group P. Postoperative CT showed that the degree of sternal deviation and stability were comparable between the groups. Similarly, the numerical rating score of pain during rehabilitation showed no difference between the groups. Even after adjusting for patient characteristics using propensity score matching method, no significant differences in sternal gaps, stability, and numerical rating score of pain were observed. Of note, no material-related adverse event such as wound infection was found. CONCLUSIONS: We could not identify the efficacy of the sternal pin in enforcing sternal stability based on CT measurements with mild shear stress on sternum after cardiovascular surgery. Nevertheless, our results with no adverse events might encourage further investigations with a more specific cohort who is susceptible to infection but requires an additional sternal fixation. TRIAL REGISTRATION: This study was registered in University Hospital Medical Information Network Clinical Trial Registry (UMIN000017357).

3.
Anal Sci ; 38(5): 749-757, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35298794

RESUMO

Acibenzolar-S-methyl (ASM) is the most commercially successful biological antibacterial agent used for crop through systemic acquired resistance (SAR). In this study, a reproducible and accurate procedure, based on the spectrophotometric/microplate reader analysis, has been developed to detect ASM in tobacco leaves. This method involves oxidation of methyl mercaptan by the Ellman's reagent 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB) to form the yellow derivative 5'-thio-2-nitrobenzoic acid (TNB2-), measurable at 412 nm. Methyl mercaptan can be produced by either the ASM transesterification with methanol or the SA-binding protein 2 (SABP2)-catalyzed ASM hydrolysis. The proportions of methanol, reaction time, temperature, the concentrations of EDTA and DTNB were optimized in a 96-well plate. The calibration curve of ASM was linear over the range of 25.2-315 µg g-1. The results of the intra- and inter-day accuracy and precision data were within the FDA acceptance criteria. With ASM as substrate, the turnover number of SABP2 was determined, with the kcat value of 31.1 min-1 using the Michaelis-Menten equation. In tobacco plants treated with 100 µM ASM, it was decreased as time elapsed in treated tobacco, reaching negligible values 72 h after treatment. The optimized method was applied for the determination of ASM transesterification with methanol and the kinetic data determination of SABP2-catalyzed ASM hydrolysis.


Assuntos
Metanol , Tabaco , Proteínas de Transporte/metabolismo , Catálise , Ácido Ditionitrobenzoico/metabolismo , Hidrólise , Compostos de Sulfidrila/análise , Tiadiazóis
4.
Langmuir ; 38(12): 3868-3875, 2022 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-35298179

RESUMO

The development of isothermal nucleic acid amplification techniques has great significance for highly sensitive biosensing in modern biology and biomedicine. A facile and robust exponential rolling circle amplification (RCA) strategy is proposed based on primer-remodeling amplification jointly via a repair enzyme and polymerase, and uracil-DNA glycosylase (UDG) is selected as a model analyte. Two kinds of complexes, complex I and complex II, are preprepared by hybridizing a circular template (CT) with a uracil-containing hairpin probe and tetrahydrofuran abasic site mimic (AP site)-embedded fluorescence-quenched probe (AFP), respectively. The target UDG specifically binds to complex I, resulting in the generation of an AP site, followed by cleavage via endonuclease IV (Endo IV) and the successive trimming of unmatched 3' terminus via phi29 DNA polymerase, thus producing a useable primer-CT complex that actuates the primary RCA. Then, numerous complex II anneal with the first-generation RCA product (RP), generating a complex II-RP assembly containing AP sites within the DNA duplex. With the aid of Endo IV and phi29, AFP, as a pre-primer in complex II, is converted into a mature primer to initiate additional rounds of RCA. So, countless AFPs are cleaved, releasing remarkably strong fluorescent signals. The biosensor is demonstrated to enable rapid and accurate detection of the UDG activity with an improved detection limit as low as 4.7 × 10-5 U·mL-1. Moreover, this biosensor is successfully applied for UDG inhibitor screening and complicated biological samples analysis. Compared to the previous exponential RCA methods, our proposed strategy offers additional advantages, including excellent stability, optional design of CT, and simplified operating steps. Therefore, this proposed strategy may create a useful and practical platform for ultrasensitive detection of low levels of analytes in clinical diagnosis and fundamental biomedicine research.


Assuntos
Técnicas Biossensoriais , Uracila-DNA Glicosidase , Técnicas Biossensoriais/métodos , Reparo do DNA , Corantes Fluorescentes , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Uracila-DNA Glicosidase/análise , Uracila-DNA Glicosidase/metabolismo , alfa-Fetoproteínas
5.
Eur J Radiol ; 148: 110142, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35066341

RESUMO

PURPOSE: This study proposes an objective method of quantifying the vortex flow in pulmonary arteries to compare the duration of its presence before and after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Thoracic 4D-flow magnetic resonance imaging was performed in 28 CTEPH patients before and after BPA. Planes were set in pulmonary arteries to evaluate volume flow rate (VFR), the duration, and area of backward flow in the pulmonary trunk, which is a component of the vortex flow. The full width at half maximum (FWHM) of the peak of the time course of VFR of backward flow was assessed to quantify the duration of the vortical flow. RESULTS: Although overall flow patterns after BPA appeared to be the same as the one before BPA, significant decreases in the FWHM, area, and VFR of the backward flow after BPA were found (FWHM: before, 1.88 × 10-1 ± 1.51 × 10-2 [cardiac cycle] vs. after, 1.65 × 10-1 ± 1.86 × 10-2 [cardiac cycle]; area ratio: before, 2.67 × 10-1 ± 1.30 × 10-2 vs. after, 2.38 × 10-1 ± 1.31 × 10-2; VFR: before, 13.6 ± 2.21 [mL/s] vs. after, 11.3 ± 2.36 [mL/s]). CONCLUSION: BPA promoted significant decreases in the FWHM, area, and VFR of backward flow in the pulmonary trunk, thereby facilitating efficient blood transport. The tendencies for these changes were to be larger for cases where BPA more greatly decreased the pressure. The results suggest that the FWHM, area, and VFR are useful indicators for the noninvasive evaluation of the therapeutic effects of BPA.


Assuntos
Angioplastia com Balão , Hipertensão Pulmonar , Embolia Pulmonar , Angioplastia com Balão/métodos , Doença Crônica , Humanos , Pulmão , Artéria Pulmonar/diagnóstico por imagem , Embolia Pulmonar/complicações , Embolia Pulmonar/diagnóstico por imagem
6.
J Pharm Biomed Anal ; 207: 114420, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34662781

RESUMO

Retention behavior of two structural isomeric pentacyclic triterpenic acids, maslinic acid and corosolic acid, was investigated by reverse phase high performance liquid chromatography (HPLC) with hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as mobile phase additive. Inclusion complexation of maslinic acid, corosolic acid with hydroxypropyl-ß-cyclodextrin was evaluated under different concentration of hydroxypropyl-ß-cyclodextrin. Apparent formation constant (Km) between methanol and hydroxypropyl-ß-cyclodextrin was determined to be 13.82 L mol-1 under 25 °C using UV-spectrophotometry. Two retention models were employed individually for evaluation of inclusion complexation between the two pentacyclic triterpenic acids and hydroxypropyl-ß-cyclodextrin. It was found that a higher apparent formation constant (Kf) for corosolic acid and hydroxypropyl-ß-cyclodextrin was obtained, 19115 L mol-1, indicating that a greater affinity of hydroxypropyl-ß-cyclodextrin with corosolic acid was produced compared with that of maslinic acid, 11775 L mol-1, in the selected mobile phase, and stoichiometric ratio for both of inclusion complex was found to be 1:1. Thermodynamic analysis showed that a negative standard enthalpy change (ΔH) and an entropy change (ΔS*) for analyte transfer were obtained, where ΔH of maslinic acid and corosolic acid was found to be -10.188 kJ mol-1 and -10.650 kJ mol-1, ΔS* of two compounds was -2.092 and -2.180, respectively, indicating that transfer of structural isomers from mobile phase to stationary phase was enthalpically driven. Meanwhile, positive values were obtained for standard enthalpy change and standard entropy change, 136 kJ mol-1 and 274 kJ mol-1 and 536 J mol-1 K-1and 1004 J mol-1 K-1, for inclusion complexation between maslinic acid, corosolic acid and hydroxypropyl-ß-cyclodextrin, while negative values were obtained for Gibbs free energy during formation of inclusion complex, -160 kJ mol-1 and -299 kJ mol-1, indicating a spontaneous inclusion reaction happened.


Assuntos
beta-Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Cromatografia Líquida , Cromatografia de Fase Reversa , Triterpenos Pentacíclicos , Termodinâmica
7.
Anal Chem ; 93(36): 12383-12390, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34449197

RESUMO

Circulating extracellular vesicles (EVs) are promising biomarkers for the early diagnosis and prognosis of cancer in a non-invasive manner. However, the rapid and accurate identification of EVs in complex biological samples is technically challenging, which is attributed to the requirement of extensive sample purification and unsatisfactory detection accuracy due to the disturbance of interfering proteins. Herein, a simultaneous binding of double-positive EV membrane protein-based recognition mode (DRM) is proposed. By the combination of DRM-mediated toehold activation and G-quadruplex DNAZyme-catalyzed etching of Au@Ag nanorods (Au@Ag NRs), we have developed an accurate, non-purified, low-cost, and visual strategy for EV identification. The synchronous binding of double-positive proteins on EV membranes is validated by confocal laser scanning microscopy analysis. This approach exhibits excellent specificity and sensitivity toward EVs ranging from 1.0 × 105 to 1.0 × 109 particles/mL with a detection limit of 6.31 × 104 particles/mL. Moreover, we have successfully realized non-purified EV quantification in complex biological media. In addition, target-initiated catalyzed hairpin assembly (CHA) is integrated with G-quadruplex DNAZyme-catalyzed color variation of Au@Ag NRs; thus, low-background EV detection can be achieved by the naked eye. Furthermore, our strategy is easy to adapt to high-throughput formats by using an automatic microplate reader, which could be expected to meet the requirements for high-throughput detection of clinical samples. With its capacities of rapidness, portability, affordability, high throughput, non-purification, and visual detection, this strategy could provide a practical tool for accurate identification of EVs and early diagnosis of cancer.


Assuntos
DNA Catalítico , Vesículas Extracelulares , Quadruplex G , Nanotubos , Neoplasias , Humanos
8.
Analyst ; 146(17): 5413-5420, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34346408

RESUMO

In this study, a novel, rapid and ultrasensitive fluorescence strategy using the three-dimensional (3D) dynamic DNA walker (DW)-induced branched hybridization chain reaction (bHCR) has been proposed for the detection of ampicillin (AMP). The sensing system was composed of an Nt·Bbvcl-powered DNA walker blocked by an AMP aptamer, hairpin-shaped DNA track probe (TP) and four kinds of metastable hairpin probes as the substrates of bHCR, which triggered the formation of the split G-quadruplex as the signal molecule. Due to the reasonable design, the specific binding between AMP and its aptamer activated the DW, and the DW moved on the surface of the gold nanoparticles (AuNPs) with the help of Nt·Bbvcl to produce primer probes (PPs), which induced bHCR. The products of the bHCR gathered two split G-quadruplex sequences together to form one complete G-quadruplex. The formed G-quadruplex emitted a strong fluorescence signal in the presence of thioflavin-T (ThT) to achieve the purpose of detecting AMP. The sensitivity of this method was greatly improved by the use of the 3D DNA walker and bHCR. The split G-quadruplex enhanced the signal-to-noise ratio (SNR). Under the optimal experimental conditions, a good correlation was obtained between the fluorescence intensity of the sensing system and the concentration of AMP ranging from 5 pM to 500 nM with a limit of detection (LOD) of 3.68 pM. Simultaneously, the method has been applied to the detection of antibiotics in spiked milk samples with satisfactory results.


Assuntos
Técnicas Biossensoriais , Quadruplex G , Nanopartículas Metálicas , Ampicilina , DNA/genética , Ouro , Limite de Detecção , Hibridização de Ácido Nucleico
9.
Mikrochim Acta ; 188(8): 255, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34264390

RESUMO

As an extremely important post-transcriptional regulator, miRNAs are involved in a variety of crucial biological processes, and the abnormal expressions of miRNAs are closely related to a variety of diseases. In this work, for the first time, we designed a nucleic acid lock nanostructure for specific detection of miRNA-21, which changes the self-structure to "active conformation" by binding the target, in order to generate triggers to initiate the subsequent reaction. Emphatically, this flexible nucleic acid lock is capable of self-cleaving without the assistance of external component, overcoming the disadvantages of the complex design and requiring protease assistance in traditional nanostructure. Moreover, the combination of DNAzyme and RCA technology not only greatly improves the efficiency of signal amplification but also enables primer generation to simultaneous cascade RCA amplification. Additionally, the electrochemical detection technology based on silver nanoclusters overcomes the shortcomings of traditional detection methods such as low sensitivity and complex operation. The detection limit achieved was 9.3 aM with a wide dynamic response ranging from 10 aM to 100 pM (at the DPV peak of - 0.5 V), which is comparable to most of the reported studies. Therefore, our work provided an ultra-sensitive way for the detection of miRNAs using nanostructures and revealed an effective means for disease theranostics and cancer diagnosis. In this work, for the first time, we designed a nucleic acid lock nanostructure based on its self-structural transformation for the specific detection of miRNA. And the combination of DNAzyme and cascade RCA reaction greatly improved the signal amplification efficiency.


Assuntos
DNA Catalítico/química , DNA/química , MicroRNAs/química , Sequência de Bases , Técnicas Biossensoriais , Técnicas Eletroquímicas , Células HeLa , Humanos , Limite de Detecção , Células MCF-7 , Nanopartículas Metálicas/química , Técnicas de Amplificação de Ácido Nucleico , Prata/química
10.
Sci Rep ; 11(1): 10548, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006929

RESUMO

MicroRNAs have emerged as key regulators in vascular diseases and are involved in the formation of atherosclerotic lesions. However, the atherosclerotic-specific MicroRNAs and their functional roles in atherosclerosis are unclear. Here, we report that miR-378c protects against atherosclerosis by directly targeting Sterile Alpha Motif Domain Containing 1 (Samd1), a predicted transcriptional repressor. miR-378c was strikingly reduced in atherosclerotic plaques and blood of acute coronary syndrome (ACS) patients relative to healthy controls. Suppression of miR-378c promoted vascular smooth muscle cells (VSMCs) phenotypic transition during atherosclerosis. We also reported for the first time that Samd1 prolonged immobilization of LDL on the VSMCs, thus facilitated LDL oxidation and subsequently foam cell formation. Further, we found that Samd1 contains predicted DNA binding domain and directly binds to DNA regions as a transcriptional repressor. Together, we uncovered a novel mechanism whereby miR-378c-Samd1 circuit participates in two key elements of atherosclerosis, VSMCs phenotypic transition and LDL oxidation. Our results provided a better understanding of atherosclerosis pathophysiology and potential therapeutic management by targeting miR-378c-Samd1 circuit.


Assuntos
Aterosclerose/patologia , Células Espumosas/patologia , MicroRNAs/fisiologia , Músculo Liso Vascular/metabolismo , Receptores de LDL/fisiologia , Animais , Células Cultivadas , Regulação para Baixo , Humanos , Camundongos , Músculo Liso Vascular/citologia , Oxirredução , Fenótipo
11.
J Chromatogr A ; 1646: 462066, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-33845265

RESUMO

Maslinic acid and corosolic acid with high purity were successfully separated from Eriobotrya japonica (Thunb.) leaves by two-step countercurrent chromatographic separation. Two biphasic solvent systems composed of petroleum ether-ethyl acetate-ethanol-water (6:4:5:5, v/v) and petroleum ether-ethyl acetate-ethanol-0.10 mol/L of hydroxypropyl-ß-cyclodextrin with pH 7.0 (8:2:3.5:6.5, v/v) were selected according to the partition performance of the main structural isomeric pentacyclic triterpenes. The influences of pH value and concentration of hydroxypropyl-ß-cyclodextrin in separation of two isomers were investigated. In first step countercurrent chromatographic separation, a mixture of two target structural isomers (14.12 mg of sample I) was separated from 40.00 mg of a partially purified sample. In second step countercurrent chromatographic separation, maslinic acid and corosolic acid were completely isolated from 12.00 mg of sample I with hydroxypropyl-ß-cyclodextrin as aqueous phase additive. The recoveries of the two isomers were over 90%, yielding 5.18 mg of maslinic acid and 5.47 mg of corosolic acid, respectively.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/química , Distribuição Contracorrente/métodos , Eriobotrya/química , Triterpenos Pentacíclicos/isolamento & purificação , Folhas de Planta/química , Cromatografia Líquida de Alta Pressão/métodos , Triterpenos Pentacíclicos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Estereoisomerismo
12.
Gland Surg ; 10(2): 629-644, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33708546

RESUMO

BACKGROUND: The techniques of DNA microarray and bioinformatic analysis have exhibited efficiency in identifying dysregulated gene expression in human cancers. In this study, we used integrated bioinformatics analysis to improve our understanding of the pathogenesis of papillary thyroid cancer (PTC). METHODS: In this study, we integrated four Gene Expression Omnibus (GEO) datasets, GSE33630, GSE35570, GSE60542 and GSE29265, including 136 normal samples and 157 PTC specimens. The contents of the four datasets are based on GPL570, an Affymetrix Human Genome U133 Plus 2.0 array. Gene ontology (GO) analysis was used to identify characteristic the biological attributes of differentially expressed genes (DEGs) between PTC and normal samples. GO annotation was performed on the DEGs obtained, and the process relied on the DAVID online tool. Kyoto Encyclopedia of Genes and Genomes (KEGG) approach enrichment analyses were adopted to obtain the basic functions of the DEGs. The KOBAS online analysis database was used to complete DEG KEGG pathway comparison and analysis. The search tool (STRING) database was mainly used to search for interacting genes and complete the construction of protein-protein interaction (PPI) networks. RESULTS: Five hundred-ninety DEGs were consistently expressed in the four datasets; 327 of them were upregulated, while 263 were downregulated. Ten DEGs, including five upregulated (ENTPD1, THRSP, KLK10, ADAMTS9, MIR31HG) and five downregulated (SCARA5, EPHB1, CHRDL1, LOC440934, FOXP2) genes, were randomly selected for q-PCR in our own tissue samples to validate the integrated data. The most highly enriched GO terms were extracellular exosome (GO:0070062), cell adhesion (GO:0070062), positive regulation of gene expression (GO:0010628), and extracellular matrix (ECM) organization (GO:0030198). KEGG pathway analysis was performed, and it was found that abnormally expressed genes effectively participated in pathways such as tyrosine metabolism, complement and coagulation cascades, cell adhesion molecules (CAMs), transcriptional misregulation and ECM-receptor interaction pathways. CONCLUSIONS: Five hundred-ninety DEGs were identified in PTC by integrated microarray analysis. The GO and KEGG analyses presented here suggest that the DEGs were enriched in extracellular exosome, tyrosine metabolism, CAMs, complement and coagulation cascades, transcriptional misregulation and ECM-receptor interaction pathways. Functional studies of PTC should focus on these pathways.

13.
Anal Chim Acta ; 1143: 21-30, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33384119

RESUMO

DNA walkers, as intelligent artificial DNA nanomachines, have been widely used as efficient nucleic acid amplification tools that the detection sensitivity can be improved by incorporating DNA walkers into DNA biosensors. Nevertheless, since the premature release or flameout in a region of locally exhausted substrate, the walking efficiency of DNA walkers remains unsatisfactory. In this work, we design a smart tripedal DNA walker that is formed by target-initiated catalyzed hairpin assembly (CHA), which can move along the DNA duplex tracks on electrode driven by toehold-mediated DNA strand displacement (TMSD) for transduction and amplification of electrochemical signals. Emphatically, this flexible tripedal DNA walker is capable of walking freely along the tracks with unconstrained walking range. Moreover, the design of multi-legged walker can weaken the derailment of leg DNA and shorten the moving time on electrode, ensuring the processive walking with high efficiency. Additionally, the persistent walking of tripedal walker is driven by cascading TMSD, which eliminates the defects of high cost and instability of enzyme-assisted amplification technology. Therefore, the tripedal DNA walker-based electrochemical biosensor has enormous potential for the applications of OTA detection, and reveals a new avenue for food safety analysis and clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , DNA , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico , Ocratoxinas , Andadores
14.
J Chromatogr A ; 1637: 461804, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33352504

RESUMO

2-(3-Methylphenyl)propanic acid and 2-(4-methylphenyl)propanoic acid were successfully enantioseparated by countercurrent chromatography using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as a chiral selector. 2-(2-Methylphenyl)propanoic acid was also studied to compare the enantioseparation ability of three isomeric 2-(methylphenyl)propanoic acids. Totally 20 mg of 2-(3-methylphenyl)propanic acid and 20mg of 2-(4-methylphenyl)propanic acid were enantioseparated individually by countercurrent chromatography. Recovery for the (±)-2-(3-methylphenyl)propanic acid enantiomer was in the range of 85%-90% with 98.0%-98.8% purity and recovery for the (±)-2-(4-methylphenyl)propanic acid enantiomer was in the range of 80%-83% with 97.0%-98.0% purity. The enantioseparation factor in countercurrent chromatography for 2-(4-methylphenyl)propanic acid and 2-(3-methylphenyl)propanic acid were 1.31 and 1.26, and the peak resolution in HPLC reached 2.2 and 1.4. However, no enantioseparation could be found for 2-(2-methylphenyl)propanic acid. In addition, the inclusion complexes were investigated by UV spectrophotometer. The inclusion formation constant of inclusion complex between 2-(4-methylphenyl)propanic acid, 2-(3-methylphenyl)propanic acid, 2-(2-methylphenyl)propanic acid and HP-ß-CD were determined as 121.73 mol/L, 78.12 mol/L and 53.18 mol/L, respectively. The present results showed that enantiorecognition was greatly affected by substituted positions of methyl group on the benzene ring. Combined with our previous results, the steric hindrance had a significant effect on inclusion interaction between HP-ß-CD and racemic 2-(substitutedphenyl)propanoic acids. No enantiorecognition could be achieved for 2-(substitutedphenyl)propanoic acids with ortho-substituent group on benzene, while the influence of meta- and para- group on enantiorecognition varies with different substituent groups on benzene ring.


Assuntos
Distribuição Contracorrente/métodos , Propionatos/química , 2-Hidroxipropil-beta-Ciclodextrina/química , Cromatografia Líquida de Alta Pressão/métodos , Espectrofotometria Ultravioleta , Estereoisomerismo
15.
J Sep Sci ; 44(3): 752-758, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33247875

RESUMO

2-(4-Chlorophenyl)succinic acid was successfully enantioseparated by countercurrent chromatography using hydroxypropyl-ß-cyclodextrin as chiral selector. A two-phase solvent system composed of n-hexane-ethyl acetate-0.1 mol/L phosphate buffer with pH 2.65 (5:5:10, v/v) was selected. Enantioselective liquid-liquid extraction was used to optimize the enantioseparation conditions. Meanwhile, the influence of injection volume on resolution in countercurrent chromatography was investigated and a linear relationship between the inflection point of injection volume and sample loading was tentatively obtained. The peak resolution will decrease significantly when the injection volume over the inflection point was used. In addition, it could be found that the smaller amount of sample loading, the larger impact of injection volume on resolution could be observed, which might serve as a good reference for the selection of sample volume in enantioseparations by countercurrent chromatography. Under optimized conditions, 20 mg of 2-(4-chlorophenyl)succinic acid racemate dissolved in 10 mL of aqueous phase was successfully enantioseparated by countercurrent chromatography. The recovery for both of the enantiomer of (±)-2-(4-chlorophenyl)succinic acid reached within 70-75% with a purity of 99.0%.

16.
J Control Release ; 330: 329-340, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33358976

RESUMO

It is still a challenge to develop gene replacement therapy for retinal disorders caused by mutations in large genes, such as Stargardt disease (STGD). STGD is caused by mutations in ABCA4 gene. Previously, we have developed an effective non-viral gene therapy using self-assembled nanoparticles of a multifunctional pH-sensitive amino lipid ECO and a therapeutic ABCA4 plasmid containing rhodopsin promoter (pRHO-ABCA4). In this study, we modified the ABCA4 plasmid with simian virus 40 enhancer (SV40, pRHO-ABCA4-SV40) for enhanced gene expression. We also prepared and assessed the formulations of ECO/pDNA nanoparticles using sucrose or sorbitol as a stablilizer to develop consistent and stable formulations. Results demonstrated that ECO formed stable nanoparticles with pRHO-ABCA4-SV40 in the presence of sucrose, but not with sorbitol. The transfection efficiency in vitro increased significantly after introduction of SV40 enhancer for plasmid pCMV-ABCA4-SV40 with a CMV promoter. Sucrose didn't affect the transfection efficiency, while sorbitol resulted in a fluctuation of the in vitro transfection efficiency. Subretinal gene therapy in Abca4-/- mice using ECO/pRHO-ABCA4 and ECO/pRHO-ABCA4-SV40 nanoparticles induced 36% and 29% reduction in A2E accumulation respectively. Therefore, the ECO/pABCA4 based nanoparticles are promising for non-viral gene therapy for Stargardt disease and can be expended for applications in a variety of visual dystrophies with mutated large genes.


Assuntos
Nanopartículas , Vírus 40 dos Símios , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Terapia Genética , Camundongos , Mutação , Doença de Stargardt
17.
Chem Commun (Camb) ; 57(3): 339-342, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33315029

RESUMO

The first facile, efficient, atom-economical and regioselective palladium-catalyzed direct C-P cross-coupling of unprotected allenic alcohols with H-phosphonates for the one-pot synthesis of structurally diverse multisubstituted 2-phosphinoyl-1,3-butadienes was developed. This strategy would enrich the allene chemistry and afford new scaffolds to construct complex molecular skeletons.

18.
J Sep Sci ; 44(4): 922-930, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33284511

RESUMO

Ondansetron, a highly selective 5-hydroxytryptamine 3 receptor antagonist, was successfully enantioseparated by recycling countercurrent chromatography using sulfobutyl ether-ß-cyclodextrin as chiral selector. Important factors for the enantioseparation were optimized, including different organic solvent, type of substituted ß-cyclodextrin, pH of aqueous phase, concentration of chiral selector, and separation temperature. A biphasic solvent system composed of n-hexane: n-butyl acetate: 0.1 mol/L phosphate buffer solution pH 9.2 with 50 mmol/L of sulfobutyl ether-ß-cyclodextrin (2.5:7.5:10, v/v/v) was selected. Under optimized separation conditions, 5 mg of ondansetron was enantioseparated using recycling countercurrent chromatography, yielding 1.2 and 1.5 mg of ondansetron enantiomers with 97.5 and 95.8% purity and the recovery reached 48-60%.


Assuntos
Distribuição Contracorrente , Ondansetron/isolamento & purificação , beta-Ciclodextrinas/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Ondansetron/química , Estereoisomerismo
19.
J Cardiothorac Surg ; 15(1): 328, 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33183318

RESUMO

BACKGROUND: Sun's procedure is currently recognized as the standard procedure for acute type A aortic dissection (AAAD). But the operation istoo difficult for beginners. We hope to reduce the difficulty and complications of this operation. METHODS: The aortic arch was immediately cross-clamped after the stented graft was inserted into the distal aorta. Thereafter, the lower-body perfusion was restored. Then, anastomosis was performed between the proximal stent graft and the distal 4-branched Dacron graft. The other arteries were anastomosed to the arched branch of the 4-branched graft. RESULTS: The cardiopulmonary bypass (CPB) time was (207 ± 52) min, and the aortic cross-clamp time was (114 ± 39) min. The circulatory arrest time was (38 ± 16) sec. One patient (4%) died. The incidence of complications was stroke (4%), renal dysfunction requiring dialysis (4%), prolonged intubation(12%). CONCLUSIONS: The time of circulatory arrest in this operation is less than 1 min, which can avoid the complications caused by DHCA and decrease risk of bleeding and complexity by shifting anastomosis more proximally. The effect of our operation is similar to and even better than that of Sun's procedure. It does not even require relatively advanced skill, much experience and excellent psychological quality, especially suitable for beginners.


Assuntos
Aneurisma Dissecante/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Parada Cardíaca Induzida , Stents , Adulto , Anastomose Cirúrgica , Feminino , Humanos , Masculino , Complicações Pós-Operatórias , Estudos Retrospectivos
20.
J Chromatogr A ; 1634: 461666, 2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33197846

RESUMO

Off-line two-dimensional countercurrent chromatography has been widely applied to the isolation of complex samples, but little research on the investigation of orthogonality in the selection of biphasic solvent systems is available. In the present work, the orthogonality in the selection of a biphasic solvent system for liquid-liquid chromatographic separation of aqueous extract and ether extract from the traditional Chinese medicinal plant Polygonum cuspidatum Sieb. et Zucc was evaluated by the correlation coefficient and space occupancy rate. In total, 25 different biphasic solvent systems were tested, and 313 system combinations were analysed. A convex hull methodology was used to determine the separation space and to optimize separation conditions. The correlation coefficient matrix was transformed into dendrograms and a colour map to visualize the dissimilarity between, and orthogonality for, all solvent systems. The aqueous extracts from Polygonum cuspidatum were separated using selected biphasic solvent systems with high orthogonality: ethyl acetate-ethanol-water (70:1:70, v/v) and petroleum ether-ethyl acetate-water (1:5:5, v/v). The ether extracts from Polygonum cuspidatum were also separated using selected biphasic solvent systems with high orthogonality: petroleum-ethyl acetate-methanol-aqueous 0.25 M NH3•H2O (5:5:5:5, v/v) and petroleum-ethyl acetate-methanol-water (5:5:5:5, v/v). Thirteen compounds were successfully obtained. The experimental results demonstrated that the evaluation of orthogonality provided an alternative strategy to select an applicable solvent system for the separation of complex samples using off-line two-dimensional countercurrent chromatography.


Assuntos
Técnicas de Química Analítica/instrumentação , Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Distribuição Contracorrente , Fallopia japonica/química , Extratos Vegetais/isolamento & purificação , Éter/química , Extratos Vegetais/química , Plantas Medicinais/química , Solventes/química , Água/química
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