Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.942
Filtrar
1.
Carbohydr Polym ; 227: 115354, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590849

RESUMO

Certain polysaccharides can serve as bio-active natural polymers that provide health benefits, however their complex structures tend to induce dramatically different activities. In this work, the immunomodulatory activity of the two arabinogalactans from larch was investigated, based upon comparison of native arabinogalactans and those modified to have lesser quantities of side-chain paraphernalia. Various in vitro assays demonstrated that the native arabinogalactans increased the secretion of macrophage-derived biological factors including NO, TNF-α, IL-1ß and IL-6. Methylation analysis and nuclear magnetic resonance spectra results indicated that part side chains of arabinogalactan were successfully removed. Partial removal of the side-chains enhanced immunomodulatory activity, while excessive removal resulted in a sharp decrease in immunomodulatory activity. These results provide new evidence that alludes to the structure-function relationship of bio-active polysaccharides, furthering the case for development of a universal assessment of polysaccharide structure-function proclivities.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117467, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31425863

RESUMO

Herein, we presented two novel turn-on colorimetric and fluorescent probes based on a F- triggered SiO bond cleavage reaction, which displayed several desired properties for the quantitative detection for F-, such as high specificity, rapid response time (within 3 min) and naked-eye visualization. The fluorescence intensity at 574 nm (absorbance at 544 nm) of the solution was found to increase linearly with the concentration of F- (0.00-30.0 µM) with the detection limit was estimated to be 0.47 µM/0.48 µM. Based on these excellent optical properties, the probes were employed to monitor F- in real water samples and tea samples with satisfactory. Furthermore, it was successfully applied for fluorescent imaging of F- in living nude mice, suggesting that it could be used as a powerful tool to predict and explore the biological functions of F- in physiological and pathological processes.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 227: 117671, 2019 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-31670043

RESUMO

In this paper, a simple, economical, and green strategy is developed for producing nitrogen doped graphene quantum dots (N-GQDs) with multicolor light emission by hydrothermal treatment of Passiflora edulia Sims. The synthesized N-GQDs exhibit ideal ionic stability, hydrophilicity and anti-photobcleaching properties, and the quantum yield reaches up to about 29%. Because of with the fluorescence quenching effect, the achieved N-GQDs allow to detect Ag+ in a linear range of 10 nM-160 µM, and the limit of detection is calculated to be 1.2 nM according to the S/N of 3. Noteworthy, N-GQDs with blue, green and yellow light emissions are demonstrated via regulating the reaction time and temperature, implying a promising fluorescence adjustability. Furthermore, the N-GQDs-based fluorescent probe exhibits low cytotoxicity and favorable biocompatibility. Depending on the superior properties, our N-GQDs are applied in fluorescent ink and multicolor cell imaging. Eventually, the developed sensor is highly selective and accurate for Ag+ analysis in real water, which demonstrates the promising practical use in environmental determination and/or biomedical engineering.

5.
Nanoscale ; 11(39): 18009-18014, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31570912

RESUMO

All-inorganic perovskite (CsPbX3) quantum dots (QDs) have achieved unprecedented success in various applications due to their outstanding performance. Nevertheless, the inherent instability of these QDs severely limits their practical applications. Here, ultra-stable full visible spectrum CsPbX3 (X = Cl, Br, I) QD glasses are prepared successfully. For the first time, the full spectrum tunable up-conversion (UC) emission of CsPbX3 QD glasses ranging from 420 nm to 711 nm under excitation with an 800 nm femtosecond (fs) laser was achieved. Importantly, the two-photon absorption properties, the exciton binding energy and the UC full width at half maximum (FWHM) of CsPbCl1.5Br1.5 (blue), CsPbBr3 (green), and CsPbBr1.5I1.5 (red) QD glasses were studied in depth. Furthermore, CsPbCl1.5Br1.5 showed the highest exciton binding energy (∼87.5 meV), allowing the CsPbCl1.5Br1.5 QD glass to act as a good optical gain material that could more easily achieve amplified spontaneous emission (ASE).

6.
Mol Cell Biochem ; 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31602539

RESUMO

Adipose-derived stem cells (ADSCs) and their derivatives have aroused intense interest in fields of dermatological and aesthetic medicine. As a major component detected in ADSCs secretome, platelet-derived growth factor AA (PDGF-AA) has been reported mediating extracellular matrix deposition and remodeling, thus might contribute to its anti-aging effect. On the basis of establishing an experimental model that simulate actual skin aging by exposing HDFs to both intrinsic and extrinsic aging factors, we pretreated human dermal fibroblasts (HDFs) with ADSC-conditioned medium (ADSC-CM) before being irradiated, aiming at exploring preventive effects of ADSCs secretome against aging damages. 48 h after irradiation, we detected cellular proliferation; ß-galactosidase stain; mRNA expressions of MMP-1, MMP-9, and TIMP-1; and protein expressions of collagen I, collagen III, and elastin. Moreover, we detected related protein expression of PI3K/Akt signal pathway, which can be activated by PDGF-AA and was newly found to promote extracellular matrix protein synthesis. Concentration of PDGF-AA in the prepared ADSC-CM decreased over time and maintained excellent bioactivity at low temperature until the 11th week. ADSC-CM pretreatment can slightly or significantly improve cellular proliferative activity and reduce cellular senescence in irradiated HDFs. Besides, ADSC-CM pretreatment increased collagen I, collagen III, elastin, and TIMP-1 expressions but decreased MMP-1 and MMP-9 expressions both in irradiated and nonirradiated HDFs. ADSC-CM pretreatment significantly increased pAkt protein expression, and ECM protein expression greatly decreased in case of LY294002 application. The results were similar in three generations of HDFs, yet varied with different degrees. Generally, ADSC-CM we prepared demonstrates a certain degree of positive role in preventing HDFs from intrinsic and extrinsic aging damages and that PDGF-AA may contribute to making it become effective with some other components in ADSC-CM.

7.
Mar Pollut Bull ; 145: 118-125, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590767

RESUMO

The effects of short-term (7 days) experimental ocean acidification (-0.4 pH units) and warming (+5 °C) on anti-predator defenses of two sympatric Mytilus species from China, M. coruscus and M. edulis, in the presence and absence of predator cues were investigated. Results suggested species-specific independent negative effects of acidification and warming on the number and weight of byssal threads, the force of thread attachment, and total thread plaque area. Similar negative effects were observed for clustering behaviour, with acidification and warming independently increasing the number of solitary individuals and decreasing the percentage of mussels in clusters. Acidification effects on byssus were strongly exacerbated when predators were present. Ultimately, this study suggests that short-term exposure to experimental warming and acidification can negatively impact anti-predator defense strategies in mussels with potential ramifications for predator-prey interactions and ecological functioning in systems where mussel beds play a key ecological role.

8.
J Cutan Med Surg ; : 1203475419882336, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31591899

RESUMO

BACKGROUND: Keratoacanthomas (KAs) are neoplasms of squamous epithelium which exhibit rapid growth and are often difficult to distinguish clinically from squamous cell carcinoma. Excision is the most common treatment, but in refractory cases or for KAs in cosmetically sensitive areas, nonoperative modalities may be better suited. OBJECTIVE: To compare efficacies of topical and intralesional therapies for the treatment of KAs. METHODS: A systematic literature review was performed using Medline, Ovid, and Embase. Studies looking at the efficacy of topical or intralesional treatments for KAs were included. To compare efficacy, 2-tailed t-tests were performed, with P < .05 considered statistically significant. RESULTS: Forty-one studies were identified across 5 modalities. Both topical and intralesional treatments had high KA eradication rates (92%-100%). Intralesional 5-fluorouracil led to faster KA healing times when compared to intralesional methotrexate (3.7 vs 4.6 weeks, P = .017). Similarly, topical 5-fluorouracil led to faster time to heal than topical imiquimod (3.8 vs 7.6 weeks with imiquimod, P < .0001). CONCLUSION: For nonoperative treatment of KAs, strong evidence currently exists for both topical and intralesional therapies. Decisions on which modality to use should be made on a case-by-case basis.

10.
Chembiochem ; 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31593360

RESUMO

A novel strategy was developed for microRNA detection based on the fluorescence quenching of polydopamine (PDA) coated reduced graphene oxide (RGO) nanosheets (RGO@PDA). Compared with GO, the reduction of GO and the modification of RGO surface by PDA could not only improve the stability, dispersity, biocompatibility and cellular uptake without degeneration of unique electronic properties of graphene, but also add an electron gate for harvesting electrons as well as enabling efficient and forward electron transfer to avoid unwanted electron transfer and realize highly sensitive miRNA detection, thus a lower detection limit could be achieved in this sensing system. Remarkably, the nanoprobes consisting of RGO@PDA and fluorescein-labeled ssDNA could naturally enter cancer cells without the aid of transfection agents, as well as resisting enzymatic lysis and showing almost no effect to the cell viability. More importantly, intense and time-dependent fluorescence responses were observed from the important tumor marker microRNA-21 (miR-21) in living cells, suggesting that the proposed sensing platform shows great promise for applications in disease diagnosis as well as the fundamental research of biochemistry.

11.
Prim Care Diabetes ; 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31653588

RESUMO

BACKGROUND: Distance education or reminder by texting short message may improve HbA1c level and medication adherence to type-2 diabetes. METHODS: Electronic databases (PubMed, EBSCO, Elsevier, Springer, Wiley, and Cochrane) were searched systematically for published studies up to Mar 2019. SMD and 95% confidence interval (CI) were used to evaluate the intervention effect on HbA1c level and medication adherence. The heterogeneity of the study was estimated with the I2 statistic. The publication bias was described by Beggs' test, Egger's test and plot. RESULTS: Ten studies with 380 interventions and 275 controls were included in this meta-analysis. The Hba1c overall SMD was -0.49%, 95% CI -0.75 to 0.22%, and the overall SMD was 0.96%, 95% CI 0.45-1.47 for medication adherence. The I2 and P were 64.90%, 0.002 and 56.40%, 0.10 respectively for Hba1c level and medication adherence. CONCLUSION: SMS intervention was effective for HbA1c level and medication adherence according to this study for T2DM over first 6 months.

12.
Medicine (Baltimore) ; 98(41): e17466, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31593105

RESUMO

RATIONALE: Vertebral arteriovenous fistulas (VAVFs) are depicted with anomalous connections between the vertebral artery, or its branches, and the adjacent venous system. Most VAVFs occur as a result of direct trauma during accidents, whereas others have iatrogenic origin. PATIENT CONCERNS: We report a case of 11-year-old male who presented with right limb weakness and walking instability. DIAGNOSIS: Magnetic resonance angiography as well as digital subtraction angiogram (DSA) of the neck demonstrated a right VAVF. The cervical medulla was compressed by a dilated vein in vertebral canal. The blood supply of the fistula was from the right vertebral artery, whereas drainage was via epidural and paraspinal venous plexus. INTERVENTIONS: We introduced the TransForm Occlusion Balloon Catheter into right vertebral artery, identified the VAVF, and occluded it with the balloon. OUTCOMES: We successfully obliterated the VAVF with patency of parent vertebral artery with a balloon. The symptoms of the patient were relieved after the procedure. Two years' follow-up revealed no recurrence of the fistula. The patient is currently well. LESSONS: Patency of the parent artery following obliteration a VAVF is still a challenge. Obliteration of the VAVF with a balloon while the parent vertebral artery is still patent is very possible.


Assuntos
Fístula Arteriovenosa/cirurgia , Oclusão com Balão/métodos , Artéria Vertebral/anormalidades , Angiografia Digital , Fístula Arteriovenosa/diagnóstico por imagem , Criança , Humanos , Angiografia por Ressonância Magnética , Masculino , Pescoço/irrigação sanguínea , Pescoço/diagnóstico por imagem , Resultado do Tratamento , Grau de Desobstrução Vascular , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/cirurgia
13.
J Sep Sci ; 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31613051

RESUMO

Alkaloids are important natural products that exhibit a wide spectrum of pharmacological activities. To efficiently separate and purify them, a rosin-based polymer-bonded silica stationary phase in high-performance liquid chromatography was synthesized via the surface radical polymerization of ethylene glycol maleic rosinate acrylate and methacrylic acid onto functionalized silica. The stationary phases, columns, optimization of chromatographic conditions for alkaloids, and thermodynamic behavior of the analytes on the column were fully studied. Under the optimized conditions, the prepared column efficiently purified natural camptothecine, caffeine, and evodiamine with the corresponding purities of 92, 96, and 97%. With this work, we have developed an efficient approach to isolate alkaloids and promoted the research on rosin-based materials in biomedicine and analytical chemistry.

15.
Semin Thromb Hemost ; 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31614390

RESUMO

Thrombosis is characterized by the formation of in vivo blood clots that are localized within arterial or venous blood vessels. These thrombi form beyond the need for physiologically healthy hemostatic responses and can lead to significant medical issues for affected individuals. Unfortunately, the existing standard-of-care therapies for treating thrombosis are systemic in their therapeutic design; therefore, they interfere with the patient's physiological hemostasis. Examples of the severe clinical side effects commonly associated with currently available therapies include, but are not limited to, bleeding complications. Therefore, there is a profound demand for novel therapeutic interventions that can circumvent these debilitating complications, while offering improved therapeutic efficacy. Recent advancements in nanotechnology present an opportunity to develop novel and improved drug delivery systems to meet this clinical demand. Preclinical investigations have begun to uncover the potential of nanotechnology, particularly in the treatment of thrombosis and also in nonhemostatic cardiovascular diseases. This article reviews recent preclinical studies aimed at developing a diverse array of different nanotechnologies for treating thrombosis as well as heart diseases. This review will also outline the limitations with current nanotechnologies and what challenges need to be overcome to translate these novel therapies to the clinic.

16.
BMC Musculoskelet Disord ; 20(1): 472, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31651315

RESUMO

BACKGROUND: This study aimed to investigate the efficacy of percutaneous hemiepiphysiodesis for gradual correction of symptomatic juvenile hallux valgus (HV) deformity. METHODS: Between 2012 to 2014, 24 patients with symptomatic juvenile HV were treated by combined percutaneous medial drilling hemiepiphysiodesis of the first proximal phalanx and lateral transphyseal screw hemiepiphysiodesis of the first metatarsal at our institution. Twenty-one of 24 patients fulfilled inclusion criteria had a complete radiological and clinical follow-up of at least 2 years. Preoperative and postoperative radiographs of the feet were reviewed for measurements of hallux valgus angle (HVA), intermetatarsal angle (IMA), proximal metatarsal articular angle (PMAA), proximal phalangeal articular angle (PPAA), and metatarsal length ratio (MTLR). Clinical outcomes were assessed using the AOFAS hallux metatarsophalangeal-interphalangeal score. RESULTS: The study included 21 consecutive patients (37 ft) for analysis. The mean age at surgery was 12.0 years (SD = 1.3) and mean follow-up after surgery was 35.1 months (SD = 6.0). With the data available, the HV deformity improved in terms of the reduction of HVA by a mean of 4.7 degrees (P < .001) and the reduction of IMA by 2.2 degrees (P < .001). The PMAA and PPAA also improved significantly in the anteroposterior plane; however, the PMAA difference was insignificant in lateral plane as expected. The mean difference in the MTLR was 0.00 (P = .216) which was indicative of no length discrepancy between first and second metatarsals. The AOFAS score increased from 68.7 to 85.2 (P < .001). In correlation analysis, time to physeal closure was significantly correlated with the final HVA change (r = -.611, P = .003). CONCLUSION: Although combined hemiepiphysiodesis does not create a large degree of correction as osteotomy, yet it did improve HV deformity with adequate growth remaining in our series. It is a procedure that can be of benefit to patients with symptomatic juvenile HV from this minimal operative approach before skeletal maturity. LEVEL OF EVIDENCE: Level IV, retrospective case series.

17.
J Am Chem Soc ; 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31621320

RESUMO

Organocopper(I) compounds are recognized as carbon nucleophiles, while organocopper(III) complexes are involved in copper catalysis as intermediates to undergo a cross-coupling reaction with various anionic nucleophiles. In contrast to the chemistry of organocopper(I) and (III) compounds, organocopper(II) chemistry is virtually a missing link in integral organocopper chemistry because structurally well-defined organocopper(II) compounds have barely been isolated or studied. We report in this Article an investigation of the radical reactions of stable and structurally well-defined arylcopper(II) compounds, obtained readily from the arene C-H bond reaction of macrocyclic azacalix[1]arene[3]pyridines and Cu(ClO4)2. We have found that arylcopper(II) compounds acted as essentially radical species to undergo an efficient three-component reaction with radical initiators 2,2'-azobis(isobutyronitrile) (AIBN) or 2,2'-azobis(2,4-dimethylvaleronitrile) (ABVN) and α,ß-unsaturated compounds CH2═CHX (X = CO2CH3, CN, CONH2, COCH3, and SO2Ph) to afford polyfunctionalized products. Combined experimental and theoretical studies revealed that radicals couple directly with the Caryl atom of arylcopper(II) compounds to form Calkyl-Caryl bonds through a Cu(II)/Cu(I) mechanism. Comprehension of the formation and radical reactivity of arylcopper(II) compounds has allowed the development of a copper-catalyzed three-component radical reaction for arene C-H bond functionalization.

18.
Toxicol In Vitro ; 62: 104660, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31629066

RESUMO

Herba Epimedii is a famous Chinese edible herb, and due to its potential hepatotoxic effects, the safety associated with this herb has attracted a great deal of attention. In this study, the components of four types of the Herba Epimedii extracts were identified by HPLC-MS/MS. Among these components, 11 components that were present in all four extracts and could be obtained as reference substances were evaluated for their ability of cytotoxicity in HL-7702 and HepG2 cells, resulting in the identification of icarisid I and sagittatoside A as the most relevant with respect to the toxicity of the extracts. The targeted toxicological effects were further investigated using a series of correlated biological indicators to elucidate potentially hepatotoxic mechanisms. The results showed that the extracts and the selected compounds had varying degrees of influence on the leakage of ALT, AST and LDH; the activity of SOD, GSH and MDA; the increase in intercellular ROS; and the decrease in MMP. Among the tested substances, the ethanol extracts exhibited stronger hepatotoxicity, with icarisid I and sagittatoside A correlating with this toxic effect, and the hepatoxic mechanisms of which may be associated with damaged cell structure, increased oxidative stress and induction of apoptosis.

19.
J Colloid Interface Sci ; 559: 65-75, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31610306

RESUMO

Electroactive nanofibrous scaffold is a vital tool for the study of the various biological research fields from bioelectronics to regenerative medicine, which can provide cell preferable 3D nanofiber architecture and programmed electrical signal. However, intrinsic non-biodegradability is a major problem that hinders its widespread application in the clinic. Herein, we designed, synthesized, and characterized shell/core poly (3,4-ethylenedioxythiophene) (PEDOT)/chitosan (CS) nanofibers by combining the electrospinning and recrystallization processes. Upon incorporating a trace amount of PEDOT (1.0 wt%), the resultant PEDOT/CS nanofibers exhibited low interfacial charge transfer impedance, high electrochemical stability, high electrical conductivity (up to 0.1945 S/cm), and ultrasensitive piezoelectric property (output voltage of 22.5 mV by a human hair prodding). With such unique electrical and conductive properties, PEDOT/CS nanofibers were further applied to brain neuroglioma cells (BNCs) to stimulate their adhesion, proliferation, growth, and development under an optimal external electrical stimulation (ES) and a pulse voltage of 400 mV/cm. ES-responsive PEDOT/CS nanofibers indeed promoted BNCs growth and development as indicated by a large number and density of axons. The synergetic interplay between external ES and piezoelectric voltage demonstrates new PEDOT-based nanofibers as implantable electroactive scaffolds for numerous applications in nerve tissue engineering, human health monitoring, brain mantle information extraction, and degradable microelectronic devices.

20.
Nutr Diabetes ; 9(1): 28, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591391

RESUMO

BACKGROUND: Gestational diabetes mellitus (GDM) is a temporary form of diabetes during pregnancy, which influences the health of maternal-child in clinical practice. It is still urgent to develop new effective treatment for GDM. Naringenin is a bioactive ingredient with multiple activities including anti-diabetic. In current study, the effects of naringenin on GDM symptoms, insulin tolerance, inflammation, and productive outcomes were evaluated and the underlying mechanisms were explored. METHODS: We administrated naringenin to GDM mice and monitored the GDM symptoms, glucose and insulin tolerance, inflammation and productive outcomes. We established tumor necrosis factor alpha (TNF-α)-induced insulin resistance skeletal muscle cell model and evaluated the effects of naringenin on reactive oxygen species (ROS) production, glucose uptake and glucose transporter type 4 (GLUT4) membrane translocation. RESULTS: We found that naringenin ameliorated GDM symptoms, improved glucose and insulin tolerance, inhibited inflammation, and improved productive outcomes. It was further found that naringenin inhibited TNF-α-induced ROS production, enhanced GLUT4 membrane translocation, and glucose uptake, which were abolished by inhibition of AMP-activated protein kinase (AMPK). CONCLUSION: Naringenin improves insulin sensitivity in gestational diabetes mellitus mice in an AMPK-dependent manner.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA