Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 49
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Musculoskeletal Care ; 21(1): 66-77, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-35765712

RESUMO

OBJECTIVE: Opioids (except for tramadol) have not been shown to be effective in patients with fibromyalgia, but they can increase the risk of adverse drug reactions. The aim was to determine the treatment patterns of a group of patients with fibromyalgia and to identify the factors associated with the use of opioids in Colombia. METHODS: This was a cross-sectional study of a group of patients with fibromyalgia from a pain clinic in Colombia. Sociodemographic, clinical and pharmacological variables were identified. Descriptive, bivariate, and multivariate analyses were performed. RESULTS: A total of 559 patients were analysed, 88.6% of whom were women, and the mean age was 53.4 ± 12.6 years. A total of 40.6% received nonpharmacological management, and the majority were treated with acetaminophen (96.1%) and pregabalin (62.8%). A total of 69.6% received opioids, the most common of which was hydrocodone (36.3%). The average morphine equivalent milligrammes was 36.9 ± 91.2 (range: 2.3-750 mg), and 43.8% had intermediate/high doses. Being male (OR: 3.12; 95% CI: 1.40-6.91), having arterial hypertension (OR: 1.67; 95% CI: 1.04-2.69), obesity (OR: 2.23; 95% CI: 1.18-4.24), degenerative disease of vertebral discs (OR: 2.32; 95% CI: 1.10-4.88) and comedication with gabapentinoids (OR: 1.75; 95% CI: 1,15-2.65) were associated with a higher probability of receiving opioids, while patients treated with muscle relaxants had a lower risk of opioid treatment (OR: 0.64; 95% CI: 0.41-0.98). CONCLUSIONS: A significant proportion of patients were treated with opioids, the most common of which was hydrocodone, which goes against the recommendations of clinical practice guidelines.


Assuntos
Analgésicos Opioides , Fibromialgia , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Analgésicos Opioides/efeitos adversos , Hidrocodona/uso terapêutico , Estudos Transversais , Acetaminofen/uso terapêutico , Padrões de Prática Médica
2.
Molecules ; 27(3)2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35164255

RESUMO

Ionic liquids (ILs) and deep eutectic solvents (DESs) are the two most widely used neoteric solvents. Recently, our group described how the simple addition of acetic acid (AcOH) to 1-Ethyl-3-methylimidazolium chloride (EMIMCl) could promote the transition from the original IL to an eutectic mixture of EMIMCl and AcOH. Herein, we studied how cellulose regeneration and EMIMCl recovery from EMIMCl solutions of cellulose could be benefited by the significant differences existing between EMIMCl- and EMIMCl·AcOH-based mixtures and the easy switching from one to the other. Finally, we also demonstrated that the transition could also be accomplished by addition of acetic anhydride and water so that the process could be eventually useful for the achievement of highly acetylated cellulose.

3.
J Inorg Biochem ; 226: 111637, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34749064

RESUMO

Resistance to ß-lactam antibiotics, including the "last-resort" carbapenems, has emerged as a major threat to global health. A major resistance mechanism employed by pathogens involves the use of metallo-ß-lactamases (MBLs), zinc-dependent enzymes that inactivate most of the ß-lactam antibiotics used to treat infections. Variants of MBLs are frequently discovered in clinical environments. However, an increasing number of such enzymes have been identified in microorganisms that are less impacted by human activities. Here, an MBL from Lysobacter antibioticus, isolated from the rhizosphere, has been shown to be highly active toward numerous ß-lactam antibiotics. Its activity is higher than that of some of the most effective MBLs linked to hospital-acquired antibiotic resistance and thus poses an interesting system to investigate evolutionary pressures that drive the emergence of such biocatalysts.


Assuntos
Antibacterianos/química , Lysobacter/enzimologia , Zinco/química , beta-Lactamases/química , beta-Lactamas/química
4.
Nanotechnology ; 32(48)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34343983

RESUMO

Due to the wide applications of three-dimensional graphene (3DG) foam in bio-sensors, stretchable electronics, and conductive polymer composites, predicting its mechanical behavior is of paramount importance. In this paper, a novel multiscale finite element model is proposed to predict the compressive modulus of 3DG foams with various densities. It considers the effects of pore size and structure and the thickness of graphene walls on 3DG foams' overall behavior. According to the scanning electron microscope images, a unit cell is selected in the microscale step to represent the incidental arrangement of graphene sheets in 3DG foams. After derivation of equivalent elastic constants of the unit cell by six individual load cases, the whole unit cell is considered an equivalent element. The macroscale model is prepared by defining a representative volume element (RVE), containing a sufficient number of the equivalent elements. Assigning a stochastic local coordinate system for each equivalent element in the macro RVE provides a model that could be utilized for elastic modulus estimation of 3DG foams in macroscale. To investigate the correspondence between the theoretical results and experimental data, 3DG foams were synthesized with four densities, and their compressive behavior were evaluated. The mass densities of the prepared foams were 5.36, 8.50, 9.37, and 11.5 mg cm-3, and the corresponding measured elastic modulus for each were 6.4, 10.7, 16.9, and 29.1 kPa, respectively. The predicted modulus by the proposed model for the synthesized foams were 6.1, 13.1, 15.6 and 21.7 kPa, respectively. The results show that the maximum divergence between estimated values and experimental data is less than 25%, confirming the high capability of the model in the estimation of 3DG foams' properties.

5.
J Chem Phys ; 154(18): 184501, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34241040

RESUMO

Deep eutectic solvents (DESs) and dilutions thereof (mainly in H2O but also in many other non-aqueous solvents and co-solvent mixtures) have recently attracted great attention. It is well known that DES dilutions exhibit deviations from ideality. Interestingly, the treatment of DES as a mixture of two components or a pseudo-component is by no means trivial when determining deviations in density and, mainly, in viscosity. Herein, we studied aqueous dilutions of one of the most widely studied DES, this is, that composed of choline chloride and urea in a 1:2 molar ratio (e.g., ChCl2U). Using density and viscosity data reported in previous works, we calculated the excess molar volumes (VE) and excess viscosities (ln ηE) considering ChCl2U as either a mixture of two components or a pseudo-component, that is, taking the DES molecular weight as MChCl2U = fChClMChCl + fUMU = 86.58 g mol-1 (with fChCl = 1/3 and fU = 2/3) or as M* ChCl2U = MChCl + 2 MU = 259.74 g mol-1. We found that neither the sign of VE and VE* nor their evolution with temperature was influenced by the use of either MChCl2U or M* ChCl2U, and only the absolute magnitude of the deviation and the DES content (in wt. %) at which the minimum appears exhibited some differences. However, ln ηE and ln ηE* exhibited opposite signs, negative and positive, respectively. The odd achievement of negative ln ηE in aqueous dilutions of ChCl2U characterized by the formation of HB networks suggest the treatment of ChCl2U as a pseudo-component as more appropriate. Moreover, the role played by the presence of U in the evolution of ln ηE* with temperature was also discussed.

6.
ChemSusChem ; 13(22): 5983-5995, 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-32924284

RESUMO

High-performance energy-storage devices are receiving great interest in sustainable terms as a required complement to renewable energy sources to level out the imbalances between supply and demand. Besides electrode optimization, a primary objective is also the judicious design of high-performance electrolytes combining novel ionic liquids (ILs) and mixtures of aqueous solvents capable of offering "à la carte" properties. Herein, it is described the stoichiometric addition of a zwitterion such as betaine (BET) to protic ILs (PILs) such as those formed between methane sulfonic acid (MSAH) or p-toluenesulfonic acid (PTSAH) with ethanolamine (EOA). This addition resulted in the formation of zwitterionic-based PILs (ZPILs) containing the original anion and cation as well as the zwitterion. The ZPILs prepared in this work ([EOAH]+ [BET][MSA]- and [EOAH]+ [BET][PTSA]- ) were liquid at room temperature even though the original PILs ([EOAH]+ [MSA]- and [EOAH]+ [PTSA]- ) were not. Moreover, ZPILs exhibited a wide electrochemical stability window, up to 3.7 V vs. Ag wire for [EOAH]+ [BET][MSA]- and 4.0 V vs. Ag wire for [EOAH]+ [BET][PTSA]- at room temperature, and a high miscibility with both water and aqueous co-solvent (WcS) mixtures. In particular, "WcS-in-ZPIL" mixtures of [EOAH]+ [BET][MSA]- in 2 H2 O/ACN/DMSO provided specific capacitances of approximately 83 F g-1 at current densities of 1 A g-1 , and capacity retentions of approximately 90 % after 6000 cycles when operating at a voltage of 2.0 V and a current density of 4 A g-1 .

7.
Rev. chil. nutr ; 47(4): 588-596, ago. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1138593

RESUMO

RESUMEN Antecedentes: En Panamá se desconoce el consumo de licopeno en la dieta usual de población masculina adulta. Varios estudios reportan la relación entre el consumo de licopeno y el cáncer de próstata. El objetivo de este estudio fue determinar la ingesta de licopeno en varones adultos que acuden a dos Centros de Salud de la Provincia de Panamá. En un estudio analítico y transversal, participaron 130 hombres adultos (18-70 años) perteneciente a los Centros de Salud de Pueblo Nuevo y Parque Lefevre de Ciudad de Panamá en marzo-agosto 2018. Se aplicó cuestionario sociodemográfico y frecuencia de consumo semi-cuantitativa de 12 alimentos conocidos como fuentes de licopeno. Se realizó regresión lineal multivariada empleando método de paso a paso. Resultados: La media geométrica y rango de ± 1DE para ingesta de licopeno fue 6,8(2,5-18,6) mg/día. Sin embargo, en sujetos indígenas, ingesta de licopeno fue 3,4(0,8-14,4) mg/día. Luego de ajustar por edad, lugar, ingresos económicos y errores estándares robustos, pertenecer a una etnia indígena se asoció negativamente con ingesta dietética de licopeno, β= −4,8 mg/día; e IC95%= −9,4 a −0,2 mg/día. Conclusión: La ingesta de licopeno se encuentra dentro de rangos esperados. El mayor consumo se encontró en alimentos ultra-procesados derivados del tomate.


ABSTRACT Background: In Panama, the dietary consumption of lycopene of the male population is unknown. Several studies report the relationship between lycopene consumption and prostate cancer. Objective: To determine the intake of lycopene in adult males who attend two primary health facilities the Province of Panama. Material and methods: We conducted an analytical and cross-sectional study of 130 males (18-70 years) who attend the Pueblo Nuevo and Parque Lefevre health facilities in Panama City. The study was carried-out from March to August 2018. A sociodemographic survey and a semi-quantitative food frequency questionnaire were applied and multivariable linear regression using stepwise method was used. Results: The geometric mean and range (±1SD) of the total lycopene consumption was 6.8 (2.5-18.6) mg/day of lycopene. However, in indigenous people, lycopene intake was 3.4 (0.8-14.4) mg/day. After adjustment by age, place, income and standard robust errors, indigenous ethnicity was negatively associated with lycopene dietary intake, β= −4.8 mg/day; and 95% CI= −9.4 to-0.2 mg/day Conclusion: Lycopene intake is within the expected ranges. Indigenous ethnicity was negatively associated with lycopene dietary intake. The highest consumption was found in tomato-derived processed foods.


Assuntos
Masculino , Adulto , Pessoa de Meia-Idade , Neoplasias da Próstata , Dieta , Licopeno , Alimentos , Homens , Antioxidantes
8.
ACS Appl Mater Interfaces ; 12(26): 29181-29193, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32484323

RESUMO

Water-in-salt (WIS) electrolytes are gaining increased interest as an alternative to conventional aqueous or organic ones. WIS electrolytes offer an interesting combination of safety, thanks to their aqueous character, and extended electrochemical stability window, thanks to the strong coordination between water molecules and ion salt. Nonetheless, cost, the tendency of salt precipitation, and sluggish ionic transfer leading to poor rate performance of devices are some intrinsic drawbacks of WIS electrolytes that yet need to be addressed for their technological implementation. It is worth noting that the absence of "free'' water molecules could also be achieved via the addition of a certain cosolvent capable of coordinating with water. This is the case of the eutectic mixture formed between DMSO and H2O with a molar ratio of 1:2 and a melting point as low as -140 °C. Interestingly, addition of salts at near-saturation conditions also resulted in an increase of the boiling point of the resulting solution. Herein, we used a eutectic mixture of DMSO and H2O for dissolution of LiTFSI in the 1.1-8.8 molality range. The resulting electrolyte (e.g., the so-called aqueous-eutectic-in-salt) exhibited excellent energy and power densities when operating in a supercapacitor cell over a wide range of extreme ambient temperatures, from as low as -35 °C to as high as +65 °C.

9.
J Phys Chem B ; 124(19): 4002-4009, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32298108

RESUMO

Deep eutectic solvents (DESs) resulting from the right combination between a hydrogen-bond donor (HBD) and a hydrogen-bond acceptor (HBA) are becoming quite popular in number of applications. More recently, natural DESs (NADESs) containing sugars, natural organic acids, and amino acids as HBDs and ChCl as HBA have received great attention because of their further environmental sustainability as compared to regular DESs. Within this context, mixing water in controlled amounts has been widely accepted as a simple and practical way of altering DES chemical and thermodynamic properties, with viscosity and conductivity experiencing the most significant changes. However, the number of papers describing eutectic mixtures with water as the only HBD is scarce and basically none has been done in fundamental terms. Herein, we investigated mixtures composed of water as the only HBD and ChCl as the HBA using differential scanning calorimetry (DSC) as well as 1H nuclear magnetic resonance (NMR) and Brillouin spectroscopies. We found the aqueous dilution of ChCl/2H2O with a ChCl/2H2O content of ca. 80 wt % was an eutectic. Interestingly, this mixture could be considered a NADES according to its eutectic distance (ΔTme), in range to eutectics obtained in aqueous dilutions of salt hydrates.

10.
Adv Mater ; 31(39): e1903418, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31392770

RESUMO

Ionic liquids (ILs) are being widely used in many diverse areas of social interest, including catalysis, electrochemistry, etc. However, issues related to hygroscopicity of many ILs and the toxic and/or nonbiodegradable features of some of them limit their practical use. Developing materials capable of IL recovery from aqueous media and dehydration, thus allowing their recycling and subsequent reutilization, in a single and efficient process still poses a major challenge. Herein, electrically conductive aerogels composed of carbon nanofibers (CNFs) with remarkable superhydrophobic features are prepared. CNF-based 3D aerogels are prepared through a cryogenic process, so called ice-segregation-induced self-assembly (ISISA) consisting of the unidirectional immersion of an aqueous chitosan (CHI) solution also containing CNFs in suspension into a liquid nitrogen bath, and subsequent freeze-drying. The CNF-based 3D aerogels prove effective for absorption of ILs from aqueous biphasic systems and recovery with quite low water contents just through a single process of filtration. Moreover, the electrical conductivity of CNF-based 3D aerogels is particularly interesting to treat highly viscous ILs because the Joule effect allows not only shortening of the absorption process but also enhancement of the flux rate when operating in flow-through conditions.

11.
ACS Appl Mater Interfaces ; 11(27): 24493-24503, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31199609

RESUMO

The elimination of small amounts of water from alcohols is by no means a trivial issue in many practical applications like, for instance, the dehumidification of biocombustibles. The use of carbonaceous materials as sorbents has been far less explored than that of other materials because their hydrophobic character has typically limited their water uptake. Herein, we designed a synthetic process based on the use of eutectic mixtures that allowed the homogeneous dispersion of graphene oxide (GO) in the liquid containing the carbon precursor, e.g., furfuryl alcohol. Thus, after polymerization and a subsequent carbonization process, we were able to obtain porous carbon-GO composites where the combination of pore diameter and surface hydrophilicity provided a remarkable capacity for water uptake but extremely low methanol and ethanol uptake along the entire range of relative pressures evaluated in this work. Both the neat water uptake and the uptake difference between water and either methanol or ethanol of our carbon-GO composites were similar or eventually better than the uptake previously reported for other materials, also exhibiting preferential water-to-alcohol adsorption, e.g., porous coordination polymers, metal-organic frameworks, polyoxometalates, and covalent two-dimensional nanosheets embedded in a polymer matrix. Moreover, water versus alcohol uptake was particularly remarkable at low partial pressures in our carbon-GO composites.

12.
J Am Chem Soc ; 141(4): 1766-1774, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30621401

RESUMO

In the present contribution, we report how through the use of metal-organic frameworks (MOFs) composed of addressable combinations of up to four different metal elements it is possible to program the composition of multimetal oxides, which are not attainable by other synthetic methodologies. Thus, due to the ability to distribute multiple metal cations at specific locations in the MOF secondary building units it is possible to code and transfer selected metal ratios to multimetal oxides with novel, desired compositions through a simple calcination process. The demonstration of an enhancement in the electrocatalytic activity of new oxides by preadjusting the metal ratios is here reported for the oxygen reduction reaction, for which activity values comparable to commercial Pt/C catalysts are reached, while showing long stability and methanol tolerance.

13.
Materials (Basel) ; 10(4)2017 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-28772715

RESUMO

The incorporation of multi-walled carbon nanotubes (MWCNTs) into chondroitin sulphate-based scaffolds and the effect on the structural, mechanical, conductive, and thermal properties of the resulting scaffolds is investigated. Three-dimensional hierarchical materials are prepared upon the application of the ice segregation-induced self-assembly (ISISA) process. The use of ice as structure-directing agents avoids chemicals typically used for this purpose (e.g., surfactants, block copolymers, etc.), hence, emphasising the green features of this soft-templating approach. We determine the critical parameters that control the morphology of the scaffolds formed upon ice-templating (i.e., MWCNTs type, freezing conditions, polymer and MWCNT concentration). MWCNTs are surface functionalized by acidic treatment. MWCNT functionalization is characterized by Raman, Fourier transfer infrared (FTIR) and X-ray Photoelectron (XPS) spectroscopies. Scanning electron microscopy (SEM) analysis and porosity studies reveal that MWCNT content modifies the morphology of the macroporous structure, which decreases by increasing MWCNT concentration. Differences in scaffold morphology should be translated into their conductivity and mechanical properties. As a general trend, the Young's modulus and the electrical conductivity of the scaffolds increase with the MWCNT content. Preliminary biocompatibility tests with human osteoblast-like cells also reveal the capability of these structures to support cell growth.

14.
Int J Ophthalmol ; 10(1): 135-139, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28149790

RESUMO

AIM: To assess if the included vascular endothelial growth factor (VEGF) polymorphisms rs3025035, rs3025021 and rs2010963 are associated to proliferative retinopathy in a Mexican population with type 2 diabetes mellitus (T2DM). METHODS: A case-control study was conducted in adult individuals with T2DM associated to proliferative retinopathy or non-proliferative retinopathy from Oct. 2014 to Jun. 2015 from the Retina Department of the Asociation to Prevent Blindness in Mexico. The selected patients were adults with a diagnosis of T2DM ≥5y. All subjects had a comprehensive ocular examination and the classification of the retinopathy severity was made considering the Early Treatment Diabetic Retinopathy Study (ETDRS) standardization protocols. Genomic DNA was extracted from whole fresh blood. All samples were genotyped by qPCR for selected VEGF polymorphisms. Hardy-Weinberg equilibrium was calculated by comparing Chi-square values between the expected and the observed values for genotype counts. RESULTS: In total 142 individuals were enrolled, 71 individuals with T2DM and associated proliferative retinopathy and 71 individuals with non-proliferative retinopathy. One-sided Fisher's exact test was performed for rs3025021 [OR (95% CI)=0.44(0.08-2.2); P=0.25] and rs2010963 [OR (95% CI)=0.63(0.25-1.6); P=0.23]. The minor allelic frequencies obtained were 26% for rs3025021, 10% for rs3025035 and 61% for rs2010963. The pairwise linkage disequilibrium between the three SNP was assessed, and was as follows: rs3025021 vs rs3025035: D'=1.0, r2=0.1043, P≤0.0001; rs3025021 vs rs2010963: D'=0.442, r2=0.0446, P=0.149; rs3025035 vs rs2010963: D'=0.505, r2=0.0214, P=0.142. CONCLUSION: This is the first analysis involving VEGF polymorphisms and proliferative diabetic retinopathy in a Mexican population. A major finding of the present study is that none of the polymorphisms studied was significantly associated with proliferative retinopathy. Based on these results, we can infer that different populations have different associations for the same polymorphisms.

15.
ACS Omega ; 2(11): 8253-8263, 2017 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30023578

RESUMO

Neural tissue engineering approaches show increasing promise for the treatment of neural diseases including spinal cord injury, for which an efficient therapy is still missing. Encouraged by both positive findings on the interaction of carbon nanomaterials such as graphene with neural components and the necessity of more efficient guidance structures for neural repair, we herein study the potential of reduced graphene oxide (rGO) microfibers as substrates for neural growth in the injured central neural tissue. Compact, bendable, and conductive fibers are obtained. When coated with neural adhesive molecules (poly-l-lysine and N-cadherin), these microfibers behave as supportive substrates of highly interconnected cultures composed of neurons and glial cells for up to 21 days. Synaptic contacts close to rGO are identified. Interestingly, the colonization by meningeal fibroblasts is dramatically hindered by N-cadherin coating. Finally, in vivo studies reveal the feasible implantation of these rGO microfibers as a guidance platform in the injured rat spinal cord, without evident signs of subacute local toxicity. These positive findings boost further investigation at longer implantation times to prove the utility of these substrates as components of advanced therapies for enhancing repair in the damaged central neural tissue including the injured spinal cord.

16.
ACS Appl Mater Interfaces ; 8(26): 16939-49, 2016 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-27294287

RESUMO

We have demonstrated that l-lactide (LLA) forms a eutectic mixture with ε-caprolactone (CL) in a 30:70 mol ratio with a melting point of -19 °C. Taking advantage of the liquid nature and polarity at the LLA-CL eutectic mixture, we have formulated oil-in-eutectic-mixture high-internal-phase emulsions (HIPEs) by stepwise addition of the oil phase (tetradecane) into the continuous phase (mixture of surfactant and LLA-CL eutectic mixture) at room temperature and under stirring. The oil-in-LLA-CL-eutectic-mixture HIPEs were polymerized in the presence of both the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and methanesulfonic acid (MSA) and the initiator benzyl alcohol (BnOH) at 37 °C and without the addition of any extra reagent or solvent in one single pot. The catalytic selectivities of DBU and MSA for the ring-opening polymerizations of LLA and CL, respectively, allowed the synthesis of macroporous poly(l-lactide)/poly(ε-caprolactone) blend materials. The resulting materials exhibited a macroporous morphology that resembled that of the HIPE internal-phase droplets used as templates. These materials proved effective as oil absorbents for oil/water separation with not only a noticeable performance, similar to that of conventional sorbents in terms of both selectivity and recyclability, but also unprecedented safe disposability, certainly of interest for applications in the cleanup of industrial oily wastewaters and oil spills, thanks to the biodegradable features of both poly(ε-caprolactone) and poly(l-lactide).

17.
Macromol Biosci ; 16(2): 255-65, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26439882

RESUMO

Ordering neural cells is of interest for the development of neural interfaces. The aim of this work is to demonstrate an easy-to-use, versatile, and cost/time effective laser-based approach for producing platforms that promote oriented neural growth. We use laser interferometry to generate fringed channels with topography on partially reduced graphene oxide layers as a proof-of-concept substrate. We study cell adhesion, morphology, viability, and differentiation in cultures of embryonic neural progenitor cells on platforms with a 9.4 µm period. Results evidence that fringed platforms significantly promote neurite alignment (≈50% at 6 d), while preserving viability and neural differentiation.


Assuntos
Técnicas de Cultura de Células/métodos , Embrião de Mamíferos/metabolismo , Lasers , Células-Tronco Neurais/metabolismo , Neuritos/metabolismo , Animais , Adesão Celular , Células-Tronco Neurais/citologia , Ratos
18.
ACS Appl Mater Interfaces ; 7(6): 3854-60, 2015 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-25610989

RESUMO

Liquid marbles (LMs) are nonsticky droplets covered by micro- or nanometrically scaled particles and obtained by simply rolling small amounts of a liquid in a very hydrophobic powder. Since pioneer work by Aussillous and Quéré, a wide palette of hydrophobic materials for the preparation of LMs, as well as potential applications, have been reported. Because of the bioinspired origin of this concept, the applicability of LMs in biomedicine is gaining increasing attention, with remarkable advances in their use as microbioreactors for blood typing, drug screening, and tumor growth, among others. Herein, we explore the novel use of LMs as a biotechnological tool for the cryopreservation of mammalian cells as an alternative to conventional methods, which typically require the use of cryopreservant agents that commonly associate with some degree of cell toxicity. Murine L929 fibroblasts, a reference cell line for cytotoxicity studies, and poly(tetrafluoroethylene), a hydrophobic polymer widely used in cardiovascular surgery, were selected for the preparation of the cell-containing LMs. Our results reveal that there is a safe range of droplet volumes and cell densities that can be successfully used to cryopreserve mammalian cell lines and recover them after thawing without significantly affecting major cellular parameters such as adhesion, morphology, viability, proliferation, and cell cycle. We envision that progress in the exploration of cell-containing LMs could also open their impact as microreactors for the miniaturization of cytotoxicity procedures of drugs and materials in which powerful tools for cell evaluation such as flow cytometry could be used because of the elevated amount of cells handled.


Assuntos
Criopreservação/instrumentação , Fibroblastos/química , Polímeros/química , Animais , Linhagem Celular , Proliferação de Células , Criopreservação/métodos , Fibroblastos/citologia , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Tamanho da Partícula , Propriedades de Superfície
19.
Can J Anaesth ; 62(5): 504-12, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25549988

RESUMO

PURPOSE: Advanced maternal age (AMA) is a known risk factor for pregnancy-related venous thromboembolism. However, it is unclear if underlying differences exist in the maternal coagulation profiles of AMA vs non-AMA women. The aim of this prospective observational study was to compare peripartum thromboelastography parameters of AMA and non-AMA women undergoing elective Cesarean delivery (CD). METHODS: We compared the peripartum thromboelastographic profiles of healthy AMA women (age > 35 yr) and non-AMA women (age ≤ 35 yr) undergoing elective CD under neuraxial anesthesia. Blood samples were drawn prior to CD and at 24 hr and 72 hr post-CD. At each time point, we assessed thromboelastographic and other standard laboratory coagulation indices. We used a linear mixed-effects regression model (SAS(®) PROC MIXED) to assess between-group differences for individual thromboelastographic and laboratory coagulation parameters. RESULTS: The median [interquartile range] ages of women were 38 [37-41] yr and 29 [25-34] yr in the AMA and non-AMA groups, respectively (P < 0.001). We observed no statistically significant effect of study group on any thromboelastographic or laboratory coagulation parameters. No statistically significant correlations were found between any thromboelastographic parameter and maternal age. Peripartum thromboelastography and coagulation profiles of healthy AMA and healthy non-AMA women up to 72 hr post-CD were also similar. CONCLUSION: These data suggest that maternal thromboelastographic profiles of healthy AMA and non-AMA women undergoing elective CD are similar. The study was registered at ClinicalTrials.gov (identifier: NCT01416454).


Assuntos
Coagulação Sanguínea/fisiologia , Idade Materna , Tromboelastografia , Adulto , Fatores Etários , Cesárea , Feminino , Humanos , Modelos Lineares , Período Periparto , Gravidez , Estudos Prospectivos , Fatores de Risco
20.
Mar Drugs ; 12(11): 5619-42, 2014 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-25421320

RESUMO

Chitosan is the N-deacetylated derivative of chitin, a naturally abundant mucopolysaccharide that consists of 2-acetamido-2-deoxy-ß-d-glucose through a ß (1→4) linkage and is found in nature as the supporting material of crustaceans, insects, etc. Chitosan has been strongly recommended as a suitable functional material because of its excellent biocompatibility, biodegradability, non-toxicity, and adsorption properties. Boosting all these excellent properties to obtain unprecedented performances requires the core competences of materials chemists to design and develop novel processing strategies that ultimately allow tailoring the structure and/or the composition of the resulting chitosan-based materials. For instance, the preparation of macroporous materials is challenging in catalysis, biocatalysis and biomedicine, because the resulting materials will offer a desirable combination of high internal reactive surface area and straightforward molecular transport through broad "highways" leading to such a surface. Moreover, chitosan-based composites made of two or more distinct components will produce structural or functional properties not present in materials composed of one single component. Our group has been working lately on cryogenic processes based on the unidirectional freezing of water slurries and/or hydrogels, the subsequent freeze-drying of which produce macroporous materials with a well-patterned structure. We have applied this process to different gels and colloidal suspensions of inorganic, organic, and hybrid materials. In this review, we will describe the application of the process to chitosan solutions and gels typically containing a second component (e.g., metal and ceramic nanoparticles, or carbon nanotubes) for the formation of chitosan nanocomposites with a macroporous structure. We will also discuss the role played by this tailored composition and structure in the ultimate performance of these materials.


Assuntos
Quitosana/química , Sistemas de Liberação de Medicamentos , Nanocompostos , Animais , Liofilização , Congelamento , Géis , Humanos , Porosidade , Soluções
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...