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1.
Nanotechnology ; 35(37)2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38876085

RESUMEN

This study introduces a novel heteroleptic indium complex, which incorporates an amidinate ligand, serving as a high-temperature atomic layer deposition (ALD) precursor. The most stable structure was determined using density functional theory and synthesized, demonstrating thermal stability up to 375 °C. We fabricated indium oxide thin-film transistors (In2O3TFTs) prepared with DBADMI precursor using ALD in wide range of window processing temperature of 200 °C, 300 °C, and 350 °C with an ozone (O3) as the source. The growth per cycle of ALD ranged from 0.06 to 0.1 nm cycle-1at different deposition temperatures. X-ray diffraction and transmission electron microscopy were employed to analyze the crystalline structure as it relates to the deposition temperature. At a relatively low deposition temperature of 200 °C, an amorphous morphology was observed, while at 300 °C and 350 °C, crystalline structures were evident. Additionally, x-ray photoelectron spectroscopy analysis was conducted to identify the In-O and OH-related products in the film. The OH-related product was found to be as low as 1% with an increase the deposition temperature. Furthermore, we evaluated In2O3TFTs and observed an increase in field-effect mobility, with minimal change in the threshold voltage (Vth), at 200 °C, 300 °C, and 350 °C. Consequently, the DBADMI precursor, given its stability at highdeposition temperatures, is ideal for producing high-quality films and stable crystalline phases, with wide processing temperature range makeing it suitable for various applications.

2.
Nano Lett ; 21(16): 6851-6858, 2021 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-34383494

RESUMEN

Triboelectrification is a phenomenon that generates electric potential upon contact. Here, we report a viral particle capable of generating triboelectric potential. M13 bacteriophage is exploited to fabricate precisely defined chemical and physical structures. By genetically engineering the charged structures, we observe that more negatively charged phages can generate higher triboelectric potentials and can diffuse the electric charges faster than less negatively charged phages can. The computational results show that the glutamate-engineered phages lower the LUMO energy level so that they can easily accept electrons from other materials upon contact. A phage-based triboelectric nanogenerator is fabricated and it could produce ∼76 V and ∼5.1 µA, enough to power 30 light-emitting diodes upon a mechanical force application. Our biotechnological approach will be useful to understand the electrical behavior of biomaterials, harvest mechanical energy, and provide a novel modality to detect desired viruses in the future.


Asunto(s)
Suministros de Energía Eléctrica , Virus , Electricidad , Fenómenos Mecánicos , Nanotecnología
3.
Int J Mol Sci ; 23(19)2022 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-36232798

RESUMEN

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary cerebral small-vessel disease caused by mutations in the NOTCH3 gene. Classical pathogenic mechanisms are associated with cysteine gain or loss, but recent studies suggest that cysteine-sparing mutations might have a potential role as a pathogen. In comparison with CADASIL patients in Western countries, there are several differences in Asian patients: (1) prevalent locus of NOTCH3 mutations (exons 2-6 [particularly exon 4] vs. exon 11), (2) age at symptom onset, (3) prevalence of cerebral microbleeds and hemorrhagic stroke, (4) clinical symptoms, and (5) severity of white matter hyperintensities and typical involvement of the anterior temporal pole in magnetic resonance imaging. Both ethnicity and founder effects contribute to these differences in the clinical NOTCH3 spectrum in different cohorts. More functional investigations from diverse races are needed to clarify unknown but novel variants of NOTCH3 mutations. This review may broaden the spectrum of NOTCH3 variants from an Asian perspective and draw attention to the hidden pathogenic roles of NOTCH3 variants.


Asunto(s)
CADASIL , CADASIL/genética , Cisteína/genética , Exones , Genotipo , Humanos , Imagen por Resonancia Magnética , Mutación , Fenotipo , Receptor Notch3/genética , Receptores Notch/genética
4.
Stroke ; 51(3): 931-937, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31856691

RESUMEN

Background and Purpose- Although cilostazol has shown less hemorrhagic events than aspirin, only marginal difference was observed in hemorrhagic stroke events among patients at high risk for cerebral hemorrhage. To identify patients who would most benefit from cilostazol, this study analyzed interactions between treatment and subgroups of the PICASSO trial (Prevention of Cardiovascular Events in Asian Ischemic Stroke Patients With High Risk of Cerebral Hemorrhage). Methods- Ischemic stroke patients with a previous intracerebral hemorrhage or multiple microbleeds were randomized to treatment with cilostazol or aspirin and followed up for a mean 1.8 years. Efficacy, defined as the composite of any stroke, myocardial infarction, and vascular death, and safety, defined as the incidence of hemorrhagic stroke, were analyzed in the 2 groups. Interactions between treatment and age, sex, presence of hypertension and diabetes mellitus, index of high-risk cerebral hemorrhage, and white matter lesion burden were analyzed for primary and key secondary outcomes. Changes in vital signs and laboratory results were compared in the 2 groups. Results- Among all 1534 patients enrolled, a significant interaction between treatment group and index of high risk for cerebral hemorrhage on hemorrhagic stroke (P for interaction, 0.03) was observed. Hemorrhagic stroke was less frequent in the cilostazol than in the aspirin group in patients with multiple microbleeds (1 versus 13 events; hazard ratio, 0.08 [95% CI, 0.01-0.61]; P=0.01). A marginal interaction between treatment group and white matter change on any stroke (P for interaction, 0.08) was observed. Cilostazol reduced any stroke significantly in patients with mild (5 versus 16 events; hazard ratio, 0.36 [95% CI, 0.13-0.97]; P=0.04)-to-moderate (16 versus 32 events; hazard ratio, 0.50 [95% CI, 0.29-0.92]; P=0.03) white matter changes. Heart rate and HDL (high-density lipoprotein) cholesterol level were significantly higher in the cilostazol group than in the aspirin group at follow-up. Conclusions- Cilostazol may be more beneficial for ischemic stroke patients with multiple cerebral microbleeds and before white matter changes are extensive. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT01013532.


Asunto(s)
Aspirina/administración & dosificación , Isquemia Encefálica/tratamiento farmacológico , Hemorragia Cerebral/tratamiento farmacológico , Cilostazol/administración & dosificación , Accidente Cerebrovascular/tratamiento farmacológico , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo
5.
Small ; 16(20): e2001103, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32329574

RESUMEN

Magnetic-plasmonic nanoparticles have received considerable attention for widespread applications. These nanoparticles (NPs) exhibiting surface-enhanced Raman scattering (SERS) activities are developed due to their potential in bio-sensing applicable in non-destructive and sensitive analysis with target-specific separation. However, it is challenging to synthesize these NPs that simultaneously exhibit low remanence, maximized magnetic content, plasmonic coverage with abundant hotspots, and structural uniformity. Here, a method that involves the conjugation of a magnetic template with gold seeds via chemical binding and seed-mediated growth is proposed, with the objective of obtaining plasmonic nanostructures with abundant hotspots on a magnetic template. To obtain a clean surface for directly functionalizing ligands and enhancing the Raman intensity, an additional growth step of gold (Au) and/or silver (Ag) atoms is proposed after modifying the Raman molecules on the as-prepared magnetic-plasmonic nanoparticles. Importantly, one-sided silver growth occurred in an environment where gold facets are blocked by Raman molecules; otherwise, the gold growth is layer-by-layer. Moreover, simultaneous reduction by gold and silver ions allowed for the formation of a uniform bimetallic layer. The enhancement factor of the nanoparticles with a bimetallic layer is approximately 107 . The SERS probes functionalized cyclic peptides are employed for targeted cancer-cell imaging and separation.


Asunto(s)
Nanopartículas del Metal , Neoplasias , Oro , Fenómenos Magnéticos , Neoplasias/diagnóstico por imagen , Plata , Espectrometría Raman
6.
Biomacromolecules ; 21(7): 2938-2948, 2020 07 13.
Artículo en Inglés | MEDLINE | ID: mdl-32478527

RESUMEN

Adhesives can potentially be used to achieve fast and efficient wound closure; however, current products show poor bonding on wet surfaces, undergo swelling, and lack adequate biocompatibility. We designed a hydrogel adhesive with recombinant elastin-like polypeptides (ELPs), which are flexible proteins that can be customized for biomedical needs. The adhesive proteins are synthesized by chemically modifying the ELPs with dopamine, which contain adhesive catechol moieties. The resulting catechol-functional ELPs or Cat-ELPs can form flexible hydrogels that show stable swelling in aqueous conditions at 37 °C. We demonstrate their flexibility and viscoelastic properties through rheology. We also show the advantage of using customizable recombinant proteins to improve the material biological properties by demonstrating improved fibroblast binding on Cat-ELP by adding ELP with "RGD" peptides. We further confirmed in vivo biocompatibility and biodegradation of Cat-ELP hydrogels by implanting them in mice and monitoring for 10 weeks. Finally, we tested the bonding strength of the adhesives on porcine skin through tensile pull-off and lap-shear testing, in which we found strengths of 37 and 39 kPa, respectively. We demonstrated the tensile bonding strength by suspending a 2 kg mass on a one square inch (6.5 cm2) skin sample. As our adhesives are developed further, our strategy combining recombinant protein engineering and chemical modification will help yield an ideal bioadhesive for wound closure.


Asunto(s)
Elastina , Adhesivos Tisulares , Adhesivos , Animales , Catecoles , Hidrogeles , Ratones , Péptidos , Porcinos
7.
Nano Lett ; 19(4): 2661-2667, 2019 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-30875472

RESUMEN

Controlling the shape, geometry, density, and orientation of nanomaterials is critical to fabricate functional devices. However, there is limited control over the morphological and directional characteristics of presynthesized nanomaterials, which makes them unsuitable for developing devices for practical applications. Here, we address this challenge by demonstrating vertically aligned and polarized piezoelectric nanostructures from presynthesized biological piezoelectric nanofibers, M13 phage, with control over the orientation, polarization direction, microstructure morphology, and density using genetic engineering and template-assisted self-assembly process. The resulting vertically ordered structures exhibit strong unidirectional polarization with three times higher piezoelectric constant values than that of in-plane aligned structures, supported by second harmonic generation and piezoelectric force microscopy measurements. The resulting vertically self-assembled phage-based piezoelectric energy harvester (PEH) produces up to 2.8 V of potential, 120 nA of current, and 236 nW of power upon 17 N of force. In addition, five phage-based PEH integrated devices produce an output voltage of 12 V and an output current of 300 nA, simply by pressing with a finger. The resulting device can operate light-emitting diode backlights on a liquid crystal display. Our approach will be useful for assembling many other presynthesized nanomaterials into high-performance devices for various applications.

8.
J Stroke Cerebrovasc Dis ; 27(3): 816-818, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29107634

RESUMEN

Although intracranial arterial calcifications (IACs) are encountered in approximately 85% of patients with acute ischemic stroke (IS), the significance of IAC in plaque instability is still controversial. Because most tissues including brain tissue have vitamin D receptors, vitamin D deficiency might play multiple roles in variable sites. Here, we report a novel presentation of IS with IAC including anterior cerebral artery involvement due to vitamin D deficiency. In conclusion, although the role of IAC in cerebral infarction is still controversial, we suggest that insufficient vitamin D should be examined and treated appropriately in all patients with IS. We believe that this article provides important implications for the treatment of vitamin D deficiency in patients with IS.


Asunto(s)
Isquemia Encefálica/etiología , Enfermedades Arteriales Intracraneales/etiología , Accidente Cerebrovascular/etiología , Calcificación Vascular/etiología , Deficiencia de Vitamina D/complicaciones , Biomarcadores/sangre , Isquemia Encefálica/diagnóstico por imagen , Suplementos Dietéticos , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Enfermedades Arteriales Intracraneales/diagnóstico por imagen , Persona de Mediana Edad , Factores de Riesgo , Accidente Cerebrovascular/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Calcificación Vascular/diagnóstico por imagen , Vitamina D/análogos & derivados , Vitamina D/sangre , Vitamina D/uso terapéutico , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/diagnóstico , Deficiencia de Vitamina D/tratamiento farmacológico
9.
Int Psychogeriatr ; 29(5): 777-784, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28120733

RESUMEN

BACKGROUND: The National Institute of Neurological Disease and Stroke-Canadian Stroke Network (NINDS-CSN) 5-minute neuropsychology protocol consists of only verbal tasks, and is proposed as a brief screening method for vascular cognitive impairment. We evaluated its feasibility within two weeks after stroke and ability to predict the development of post-stroke dementia (PSD) at 3 months after stroke. METHOD: We prospectively enrolled subjects with ischemic stroke within seven days of symptom onset who were consecutively admitted to 12 university hospitals. Neuropsychological assessments using the NINDS-CSN 5-minute and 60-minute neuropsychology protocols were administered within two weeks and at 3 months after stroke onset, respectively. PSD was diagnosed with reference to the American Heart Association/American Stroke Association statement, requiring deficits in at least two cognitive domains. RESULTS: Of 620 patients, 512 (82.6%) were feasible for the NINDS-CSN 5-minute protocol within two weeks after stroke. The incidence of PSD was 16.2% in 308 subjects who had completed follow-up at 3 months after stroke onset. The total score of the NINDS-CSN 5-minute protocol differed significantly between those with and without PSD (4.0 ± 2.7, 7.4 ± 2.7, respectively; p < 0.01). A cut-off value of 6/7 showed reasonable discriminative power (sensitivity 0.82, specificity 0.67, AUC 0.74). The NINDS-CSN 5-minute protocol score was a significant predictor for PSD (adjusted odds ratio 6.32, 95% CI 2.65-15.05). DISCUSSION: The NINDS-CSN 5-minute protocol is feasible to evaluate cognitive functions in patients with acute ischemic stroke. It might be a useful screening method for early identification of high-risk groups for PSD.


Asunto(s)
Demencia/diagnóstico , Demencia/epidemiología , Pruebas Neuropsicológicas , Accidente Cerebrovascular/complicaciones , Anciano , Cognición , Femenino , Humanos , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , National Institute of Neurological Disorders and Stroke (U.S.) , Estudios Prospectivos , Curva ROC , República de Corea/epidemiología , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Estados Unidos
10.
Eur Neurol ; 78(3-4): 210-216, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28903101

RESUMEN

BACKGROUND: Stroke is a disastrous disease and a major health burden worldwide, especially in Korea. Hemorrhagic stroke (HS) accounts for approximately 20% of all the types of strokes. It is important to be able to evaluate stroke diagnoses and evolving treatments. OBJECTIVE: We aimed to identify the top-100 cited articles and assess a paradigm shift that occurred in the field of HS. METHODS: We searched all articles that had been cited more than 100 times using the Web of Science citation search tool during January 2016. Among a total of 2,651 articles, we identified the top-100 cited articles on HS. RESULTS: The number of citations for the articles analyzed in this study ranged from 1,746 to 211, and the number of annual citations ranged from 125.6 to 5.5. Most of the articles that were published in Stroke (35%) and Journal of Neurosurgery (22%), originated in the United States (n = 56), were original articles (64%), and dealt with the natural history or etiology (n = 37) and vasospasm in subarachnoid hemorrhage (n = 8). CONCLUSIONS: We analyzed the top-100 cited articles in the field of HS based on citation rates. The results provide a unique perspective on historical and academic developments in this field.


Asunto(s)
Bibliometría , Accidente Cerebrovascular , Humanos , República de Corea , Estados Unidos
11.
Neuroimage ; 139: 149-156, 2016 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-27327516

RESUMEN

The purpose of our study was to identify and characterize the 100 most-cited articles in neuroimaging. Based on the database of Journal Citation Reports, we selected 669 journals that were considered as potential outlets for neuroimaging articles. The Web of Science search tools were used to identify the 100 most-cited articles relevant to neuroimaging within the selected journals. The following information was recorded for each article: publication year, journal, category and impact factor of journal, number of citations, number of annual citations, authorship, department, institution, country, article type, imaging technique used, and topic. The 100 most-cited articles in neuroimaging were published between 1980 and 2012, with 1995-2004 producing 69 articles. Citations ranged from 4384 to 673 and annual citations ranged from 313.1 to 24.9. The majority of articles were published in radiology/imaging journals (n=75), originated in the United States (n=58), were original articles (n=63), used MRI as imaging modality (n=85), and dealt with imaging technique (n=45). The Oxford Centre for Functional Magnetic Resonance Imaging of the Brain at John Radcliffe Hospital (n=10) was the leading institutions and Karl J. Friston (n=11) was the most prolific author. Our study presents a detailed list and an analysis of the 100 most-cited articles in the field of neuroimaging, which provides an insight into historical developments and allows for recognition of the important advances in this field.


Asunto(s)
Bibliometría , Factor de Impacto de la Revista , Imagen por Resonancia Magnética/estadística & datos numéricos , Neuroimagen/estadística & datos numéricos , Publicaciones Periódicas como Asunto/estadística & datos numéricos
12.
Biomacromolecules ; 17(8): 2619-25, 2016 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-27380227

RESUMEN

Tailorable hydrogels that are mechanically robust, injectable, and self-healable, are useful for many biomedical applications including tissue repair and drug delivery. Here we use biological and chemical engineering approaches to develop a novel in situ forming organic/inorganic composite hydrogel with dynamic aldimine cross-links using elastin-like polypeptides (ELP) and bioglass (BG). The resulting ELP/BG biocomposites exhibit tunable gelling behavior and mechanical characteristics in a composition and concentration dependent manner. We also demonstrate self-healing in the ELP/BG hydrogels by successfully reattaching severed pieces as well as through rheology. In addition, we show the strength of genetic engineering to easily customize ELP by fusing cell-stimulating "RGD" peptide motifs. We showed that the resulting composite materials are cytocompatible as they support the cellular growth and attachment. Our robust in situ forming ELP/BG composite hydrogels will be useful as injectable scaffolds for delivering cell and drug molecules to promote soft tissue regeneration in the future.


Asunto(s)
Cerámica/química , Elastina/química , Hidrogeles/química , Osteoblastos/metabolismo , Ingeniería de Tejidos , Animales , Células Cultivadas , Ratones , Osteoblastos/citología , Reología
13.
Bioprocess Biosyst Eng ; 39(6): 1015-21, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26899601

RESUMEN

Chlorella vulgaris is considered as one of the potential sources of biomass for bio-based products because it consists of large amounts of carbohydrates. In this study, hydrothermal acid hydrolysis with five different acids (hydrochloric acid, nitric acid, peracetic acid, phosphoric acid, and sulfuric acid) was carried out to produce fermentable sugars (glucose, galactose). The hydrothermal acid hydrolysis by hydrochloric acid showed the highest sugar production. C. vulgaris was hydrolyzed with various concentrations of hydrochloric acid [0.5-10 % (w/w)] and microalgal biomass [20-140 g/L (w/v)] at 121 °C for 20 min. Among the concentrations examined, 2 % hydrochloric acid with 100 g/L biomass yielded the highest conversion of carbohydrates (92.5 %) into reducing sugars. The hydrolysate thus produced from C. vulgaris was fermented using the yeast Brettanomyces custersii H1-603 and obtained bioethanol yield of 0.37 g/g of algal sugars.


Asunto(s)
Chlorella vulgaris/metabolismo , Ácido Clorhídrico/metabolismo , Fermentación , Hidrólisis
14.
Anal Biochem ; 470: 7-13, 2015 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-25447463

RESUMEN

For early detection of many diseases, it is critical to be able to diagnose small amounts of biomarkers in blood or serum. One of the most widely used sensing assays is the enzyme-linked immunosorbent assay (ELISA), which typically uses detection monoclonal antibodies conjugated to enzymes to produce colorimetric signals. To increase the overall sensitivities of these sensors, we demonstrate the use of a dually modified version of filamentous bacteriophage Fd that produces significantly higher colorimetric signals in ELISAs than what can be achieved using antibodies alone. Because only a few proteins at the tip of the micron-long bacteriophage are involved in antigen binding, the approximately 4000 other coat proteins can be augmented-by either chemical functionalization or genetic engineering-with hundreds to thousands of functional groups. In this article, we demonstrate the use of bacteriophage that bear a large genomic fusion that allows them to bind specific antibodies on coat protein 3 (p3) and multiple biotin groups on coat protein 8 (p8) to bind to avidin-conjugated enzymes. In direct ELISAs, the anti-rTNFα (recombinant human tumor necrosis factor alpha)-conjugated bacteriophage show approximately 3- to 4-fold gains in signal over that of anti-rTNFα, demonstrating their use as a platform for highly sensitive protein detection.


Asunto(s)
Bacteriófago M13/genética , Ensayo de Inmunoadsorción Enzimática/métodos , Ingeniería Genética , Anticuerpos Monoclonales/inmunología , Biotina/metabolismo , Genoma Viral/genética , Humanos
15.
Biosci Biotechnol Biochem ; 79(10): 1644-53, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25971153

RESUMEN

Sulfated polysaccharides (SP) isolated from freshwater green algae, Spirogyra neglecta (Hassall) Kützing, and fractionated SPs were examined to investigate their molecular characteristics and immunomodulatory activity. The crude and fractionated SPs (F1, F2, and F3) consisted mostly of carbohydrates (68.5-85.3%), uronic acids (3.2-4.9%), and sulfates (2.2-12.2%) with various amounts of proteins (2.6-17.1%). D-galactose (23.5-27.3%), D-glucose (11.5-24.8%), L-fucose (19.0-26.7%), and L-rhamnose (16.4-18.3%) were the major monosaccharide units of these SPs with different levels of L-arabinose (3.0-9.4%), D-xylose (4.6-9.8%), and D-mannose (0.4-2.3%). The SPs contained two sub-fractions with molecular weights (Mw) ranging from 164 × 10(3) to 1460 × 10(3) g/mol. The crude and fractionated SPs strongly stimulated murine macrophages, producing considerable amounts of nitric oxide and various cytokines via up-regulation of their mRNA expression by activation of nuclear factor-kappa B and mitogen-activated protein kinases pathways. The main backbone of the most immunoenhancing SP was (1→3)-L-Fucopyranoside, (1→4,6)-D-Glucopyranoside, and (1→4)-D-Galactopyranoside.


Asunto(s)
Citocinas/agonistas , Factores Inmunológicos/química , Macrófagos/efectos de los fármacos , Polisacáridos/química , Spirogyra/química , Proteínas Algáceas/química , Proteínas Algáceas/aislamiento & purificación , Animales , Arabinosa/química , Línea Celular , Citocinas/genética , Citocinas/inmunología , Fucosa/química , Galactosa/química , Regulación de la Expresión Génica , Glucosa/química , Glucósidos/química , Factores Inmunológicos/aislamiento & purificación , Factores Inmunológicos/farmacología , Macrófagos/citología , Macrófagos/inmunología , Manosa/química , Ratones , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/inmunología , FN-kappa B/agonistas , FN-kappa B/genética , FN-kappa B/inmunología , Óxido Nítrico/biosíntesis , Óxido Nítrico/inmunología , Extractos Vegetales/química , Polisacáridos/aislamiento & purificación , Polisacáridos/farmacología , Ramnosa/química , Sulfatos/química , Ácidos Urónicos/química , Ácidos Urónicos/aislamiento & purificación , Xilosa/química
16.
Langmuir ; 30(28): 8452-60, 2014 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-24972257

RESUMEN

The development of strategies to couple biomolecules covalently to surfaces is necessary for constructing sensing arrays for biological and biomedical applications. One attractive conjugation reaction is hydrazone formation--the reaction of a hydrazine with an aldehyde or ketone--as both hydrazines and aldehydes/ketones are largely bioorthogonal, which makes this particular reaction suitable for conjugating biomolecules to a variety of substrates. We show that the mild reaction conditions afforded by hydrazone conjugation enable the conjugation of DNA and proteins to the substrate surface in significantly higher yields than can be achieved with traditional bioconjugation techniques, such as maleimide chemistry. Next, we designed and synthesized a photocaged aryl ketone that can be conjugated to a surface and photochemically activated to provide a suitable partner for subsequent hydrazone formation between the surface-anchored ketone and DNA- or protein-hydrazines. Finally, we exploit the latent functionality of the photocaged ketone and pattern multiple biomolecules on the same substrate, effectively demonstrating a strategy for designing substrates with well-defined domains of different biomolecules. We expect that this approach can be extended to the production of multiplexed assays by using an appropriate mask with sequential photoexposure and biomolecule conjugation steps.


Asunto(s)
ADN/química , Hidrazonas/química , Proteínas/química , Aldehídos/química , Hidrazinas/química , Cetonas/química , Propiedades de Superficie
17.
BMC Neurol ; 14: 244, 2014 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-25927318

RESUMEN

BACKGROUND: The American Stroke Association/American Heart Association recommended the criteria for diagnosis of vascular cognitive impairment and memory impairment (MI) is a feature in the classification of vascular mild cognitive impairment (VaMCI). VaMCI patients with MI may differ in terms of infarct location or demographic features, so we evaluated the clinical characteristics associated with MI in patients with VaMCI. METHODS: A prospective multicenter study enrolled 353 acute ischemic stroke patients who underwent evaluation using the Korean Vascular Cognitive Impairment Harmonization Standard Neuropsychological Protocol at three months after onset. The association between MI and demographic features, stroke risk factors, and infarct location was assessed. RESULTS: VaMCI was diagnosed in 141 patients, and 58 (41.1%) exhibited MI. Proportions of men and of left side infarcts were higher in VaMCI with MI than those without (75.9 vs. 57.8%, P = 0.03, 66.7 vs. 47%, P = 0.02). Multiple logistic analyses revealed that male sex (odds ratio [OR] 3.07, 95% confidence interval [95% CI] 1.12-8.42), left-side infarcts (OR 3.14, 95% CI 1.37-7.20), and basal ganglia/internal capsule infarcts (OR 4.53, 95% CI 1.55-13.22) were associated with MI after adjusting other demographic variables, vascular risk factors, and subtypes of stroke. CONCLUSIONS: MI is associated with sex and infarct location in VaMCI patients.


Asunto(s)
Enfermedad Cerebrovascular de los Ganglios Basales/psicología , Infarto Encefálico/psicología , Disfunción Cognitiva/psicología , Demencia Vascular/psicología , Trastornos de la Memoria/psicología , Anciano , Enfermedad Cerebrovascular de los Ganglios Basales/complicaciones , Infarto Encefálico/complicaciones , Disfunción Cognitiva/etiología , Estudios de Cohortes , Demencia Vascular/etiología , Femenino , Humanos , Modelos Logísticos , Masculino , Trastornos de la Memoria/etiología , Persona de Mediana Edad , Pruebas Neuropsicológicas , Oportunidad Relativa , Estudios Prospectivos , Factores de Riesgo , Factores Sexuales , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/psicología , Estados Unidos
18.
Cogn Behav Neurol ; 27(4): 189-98, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25539038

RESUMEN

OBJECTIVE AND BACKGROUND: Many patients develop cognitive impairment after an acute stroke. It is not clear whether blood pressure variability is a prognostic factor for cognitive impairment. We aimed to determine the association between blood pressure variability on hospital admission and cognitive outcome in patients with acute lacunar infarction. METHODS: We performed a retrospective analysis on 22 men and 14 women (mean age, 61.8 years) who had completed a cognitive evaluation 3 months after onset of an acute lacunar infarction. The patients had no previous functional disability or dementia, stenosis in major cerebral arteries, cardiac embolic sources, or infarct in strategic territories for cognition. We used standard deviation and coefficient of variance as parameters of blood pressure variability, and each cognitive function test z score as an outcome parameter. We performed linear regression analysis to assess the relationship between blood pressure variability and cognition, adjusted for vascular risk factors, severity of neurologic deficits, and mean blood pressure. RESULTS: High variability of both systolic and diastolic blood pressure was significantly associated with low z scores on the Controlled Oral Word Association Test and the Digit Symbol Coding test (P<0.01). High variability of diastolic blood pressure was significantly associated with low z scores on the Korean Mini-Mental State Examination and Seoul Verbal Learning Test delayed recall (P<0.01). CONCLUSIONS: Highly variable blood pressure on admission for acute lacunar infarction may predict poor cognitive outcomes, especially frontal lobe dysfunction.


Asunto(s)
Presión Sanguínea , Cognición , Demencia/etiología , Lóbulo Frontal/fisiopatología , Accidente Vascular Cerebral Lacunar/fisiopatología , Accidente Vascular Cerebral Lacunar/psicología , Enfermedad Aguda , Anciano , Anciano de 80 o más Años , Disfunción Cognitiva/etiología , Disfunción Cognitiva/fisiopatología , Demencia/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , República de Corea , Estudios Retrospectivos , Factores de Riesgo , Aprendizaje Verbal
20.
J Stroke Cerebrovasc Dis ; 23(5): 1164-70, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24315720

RESUMEN

BACKGROUND: The progression of carotid intima-media thickness (CIMT) is closely associated with ischemic stroke recurrence. However, the efficacy of cilostazol on preventing CIMT progression in stroke patients has never been investigated properly by a prospective trial. METHODS: This study is a part of "Trial of Cilostazol in Symptomatic Intracranial Arterial Stenosis-2." Six centers that are available to measure CIMT according to the protocol participated in this substudy. After 7 months of randomization, the changes of CIMT were compared between cilostazol group and clopidogrel group. CIMT was measured by a semiautomated software (Intimascope) and was presented as the mean of maximum (CIMT-max) and average (CIMT-ave) of both common carotid arteries. Linear logistic regression analysis and analysis of covariance were performed to verify the independent factors associated with CIMT progression. RESULTS: Among the 85 patients, 39 subjects were assigned to cilostazol group and 46 subjects to clopidogrel group. Follow-up CIMT significantly decreased in cilostazol group (CIMT-max: -.03 ± .11 and CIMT-ave: -.02 ± .08) compared with the increase in clopidogrel group (CIMT-max: .04 ± .20 and CIMT-ave: .04 ± .11; P = .05 and P = .04, respectively). Female, diabetes, and smoking were independently associated with the progression of CIMT, whereas the use of cilostazol was against CIMT progression from the results of linear regression analysis (P = .03 for both CIMT-max and CIMT-ave). The use of cilostazol also well predicted less progression of CIMT at follow-up after adjusting for baseline CIMT values and conventional risk factors (CIMT-max: P = .04 and CIMT-ave: P = .03). CONCLUSION: Cilostazol has a beneficial effect in preventing the progression of CIMT in ischemic stroke patients.


Asunto(s)
Isquemia Encefálica/tratamiento farmacológico , Arteria Carótida Común/efectos de los fármacos , Grosor Intima-Media Carotídeo , Estenosis Carotídea/tratamiento farmacológico , Arteriosclerosis Intracraneal/tratamiento farmacológico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Accidente Cerebrovascular/tratamiento farmacológico , Tetrazoles/uso terapéutico , Anciano , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/etiología , Arteria Carótida Común/diagnóstico por imagen , Estenosis Carotídea/complicaciones , Estenosis Carotídea/diagnóstico por imagen , Cilostazol , Clopidogrel , Progresión de la Enfermedad , Método Doble Ciego , Femenino , Humanos , Arteriosclerosis Intracraneal/complicaciones , Arteriosclerosis Intracraneal/diagnóstico por imagen , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Valor Predictivo de las Pruebas , Estudios Prospectivos , República de Corea , Factores de Riesgo , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/etiología , Ticlopidina/análogos & derivados , Ticlopidina/uso terapéutico , Factores de Tiempo , Resultado del Tratamiento
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