Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Eur J Pharm Biopharm ; 187: 96-106, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37094693

RESUMO

Raw starch microparticles (SMPs) proved efficient antigen carriers with adjuvant properties when administered via the mucosal route; however, the underlying mechanisms associated with this bioactivity are unknown. In the present study, we explored the mucoadhesion properties, fate, and toxicity of starch microparticles after mucosal administration. Nasally administered microparticles were mainly retained in nasal turbinates, reaching the nasal-associated lymphoid tissue; this step is facilitated by the ability of the microparticles to penetrate through the mucous epithelium. Likewise, we found intraduodenally administered SMPs on the small intestinal villi, follicle-associated epithelium, and Peyer's patches. Furthermore, under simulated gastric and intestinal pH conditions, we detected mucoadhesion between the SMPs and mucins, regardless of microparticle swelling. SMPs' mucoadhesion and translocation to mucosal immune responses induction sites explain the previously reported role of these microparticles as vaccine adjuvants and immunostimulants.


Assuntos
Imunização , Amido , Amido/química , Adjuvantes Imunológicos , Imunidade nas Mucosas , Administração através da Mucosa
2.
Phys Rev Lett ; 130(11): 110801, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-37001104

RESUMO

Strong local passivity is a property of multipartite quantum systems from which it is impossible to extract energy locally. Surprisingly, if the strong local passive state displays entanglement, it could be possible to locally activate energy density by adding classical communication between different partitions of the system, through so-called "quantum energy teleportation" protocols. Here, we report both the first experimental observation of local activation of energy density on an entangled state and the first realization of a quantum energy teleportation protocol using nuclear magnetic resonance on a bipartite quantum system.

3.
World J Oncol ; 13(5): 249-258, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36406197

RESUMO

Background: Breast cancer in men is a rare and poorly studied disease, and its treatment is based on women breast cancer studies. However, clinical outcome is not the same in men and women. Basic studies and clinical trials in animal models provide detailed information on cancer, origin, development, cell signaling pathways, sites of metastasis, and target molecules. It is necessary to explore the biology of breast cancer in male animal models that allow observing their similarity. Methods: The triple-negative 4T1 breast cancer model was developed in both male and female mice and studied weekly during 4 weeks. For that, twenty 8-week-old female and male BALB/c mice were used. Sixteen mice (eight males and eight females) were inoculated into the second left thoracic mammary pad with 20,000 4T1 cells, resuspended in 20 µL phosphate-buffered saline (PBS). All samples were processed for immunodetection, characterized histopathologically and immunohistochemically. Results: In this work, we describe the development of a triple-negative 4T1 breast cancer model in male BALB/c mice. Breast tumors were characterized histopathologically at different time points and corresponded to a moderately differentiated invasive ductal carcinoma, estrogen receptor ER-/progesterone receptor PR-/human epidermal growth factor receptor 2 HER2-/Ki67+, with histological grade II (moderately differentiated; a solid mass with occasional duct formation and moderate to severe nuclear pleomorphism), infiltrating the adipose and muscular tissue, and metastasis to lungs. From the results, we did not observe differences in the time of tumor development, necrosis, color change of tumor tissue, and lung metastasis between male and female mice. Even though we did not find histological differences, response to treatment and molecular signaling may be different. Conclusions: The histogenesis of male breast tumors was similar to that of female BALB/c mice. The histological and immunohistochemical characteristics of male tumors also match the features reported for stage IV human breast cancer of men and women. The murine male breast cancer model described here can be a significant tool to explore the molecular mechanisms involved in male breast cancer tumorigenesis and metastasis and may bring new approaches for clinical treatment of triple-negative breast cancer in men.

4.
Polymers (Basel) ; 13(21)2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34771212

RESUMO

In this work, the influence of carbon nanotubes (CNTs) content on the mechanical and electrical properties of four series of polymeric matrix were made and their cytotoxicity on cells was evaluated to consider their use as a possible artificial muscle. For that, polymer composite yarns were electrospun using polymeric solutions at 10 wt.%. of poly(styrene-co-acrylonitrile) P(S:AN) and P(S:AN-acrylic acid) P(S:AN-AA) at several monomeric concentrations, namely 0:100, 20:80, 40:60, 50:50 (wt.%:wt.%), and 1 wt.% of AA. Carbon nanotubes (CNTs) were added to the polymeric solutions at two concentrations, 0.5 and 1.0 wt.%. PMCs yarns were collected using a blade collector. Mechanical and electrical properties of polymeric yarns indicated a dependence of CNTs content into yarns. Three areas could be found in fibers: CNTs bundles zones, distributed and aligned CNTs zones, and polymer-only zones. PMCs yarns with 0.5 wt.% CNTs concentration were found with a homogenous nanotube dispersion and axial alignment in polymeric yarn, ensuring load transfer on the polymeric matrix to CNTs, increasing the elastic modulus up to 27 MPa, and a maximum electrical current of 1.8 mA due to a good polymer-nanotube interaction.

5.
Sci Rep ; 11(1): 14566, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267298

RESUMO

Combining traditional medicine with nanotechnology therefore opens the door to innovative strategies for treating skin and soft tissue infections (SSTIs) and also contributes to the fight against the rise of antimicrobial resistance. Acanthospermum australe (Loefl.) Kuntze is a medicinal plant used by indigenous peoples in northeastern Argentina to treat SSTIs. Spherical and stable silver nanoparticles (AgNPs) of 14 ± 2 nm were synthesized from the aqueous extract of A. australe and silver nitrate. The antimicrobial activity against main species causing SSTIs and cytotoxicity on peripheral blood mononuclear cells of AgNP solution and its synthesis components were evaluated. Compared to its synthesis components, AgNP solution showed greater antimicrobial activity and lower cytotoxicity. The antimicrobial activity of AgNPs was due to the silver and not to the metabolites of the aqueous extract present on the surface of the nanoparticles. The plant extract played an important role in the formation of stable AgNPs and acted as a modulator of cytotoxic and immune responses.


Assuntos
Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Prata/química , Dermatopatias Infecciosas/microbiologia , Infecções dos Tecidos Moles/microbiologia , Anti-Infecciosos/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Asteraceae/química , Flavonoides/análise , Química Verde , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Nanopartículas Metálicas/uso terapêutico , Testes de Sensibilidade Microbiana , Fenóis/análise , Extratos Vegetais/química
6.
Nutr Cancer ; 72(8): 1411-1421, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31635496

RESUMO

Diverse molecules with cytotoxic activity against cancer cells have been isolated from the polar extracts of different parts of various hawthorn species that grow around the world. In Mexico, hawthorn (Crataegus gracilior) is popularly consumed, but its content of anticancer substances has never been evaluated. Because antitumor substances have been identified in polar and nonpolar extracts of many plants, we evaluated the cytotoxic activity against breast cancer cells of petroleum ether, ethanol, and water extracts of the leaves and stems of C. gracilior. In contrast to other hawthorn species that contain anti-tumor substances in polar extracts, the petroleum ether extract (but not the ethanol or water extracts) of C. gracilior had cytotoxic properties (IC50 < 50 µg/mL) inducing cell death by apoptosis. Two compounds reportedly having cytotoxic activity were identified by mass spectrometry in the petroleum extract of C. gracilior: ß-sitosterol and tocopherol. Results suggest that he cytotoxic and pro-apoptotic effects of the petroleum ether extract of C. gracilior could be exerted by the joint activity of ß-sitosterol and tocopherol, possibly in combination with of other minor compounds. Because hawthorn is widely consumed in Mexico and Latin America its potential use as a functional food warrants further investigation.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Crataegus/química , Extratos Vegetais/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Leucócitos Mononucleares , México , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Caules de Planta/química
7.
Phys Rev Lett ; 123(19): 190601, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31765196

RESUMO

We examine when it is possible to locally extract energy from a bipartite quantum system in the presence of strong coupling and entanglement, a task which is expected to be restricted by entanglement in the low-energy eigenstates. We fully characterize this distinct notion of "passivity" by finding necessary and sufficient conditions for such extraction to be impossible, using techniques from semidefinite programing. This is the first time in which such techniques are used in the context of energy extraction, which opens a way of exploring further kinds of passivity in quantum thermodynamics. We also significantly strengthen a previous result of Frey et al., by showing a physically relevant quantitative bound on the threshold temperature at which this passivity appears. Furthermore, we show how this no-go result also holds for thermal states in the thermodynamic limit, provided that the spatial correlations decay sufficiently fast, and we give numerical examples.

8.
Phys Rev Lett ; 123(4): 041601, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31491253

RESUMO

We show that uniformly accelerated detectors can display genuinely thermal features even if the Kubo-Martin-Schwinger (KMS) condition fails to hold. These features include satisfying thermal detailed balance and having a Planckian response identical to cases in which the KMS condition is satisfied. In this context, we discuss that satisfying the KMS condition for accelerated trajectories is just sufficient but not necessary for the Unruh effect to be present in a given quantum field theory. Furthermore, we extract the necessary and sufficient conditions for the response function of an accelerated detector to be thermal in the infinitely adiabatic limit. This analysis provides new insight about the interplay between the KMS condition and the Unruh effect, and a solid framework in which the robustness of the Unruh effect against deformations of quantum field theories (perhaps Lorentz-violating) can be answered unambiguously.

9.
Phys Rev Lett ; 122(24): 240604, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31322371

RESUMO

We study the work cost of processes in quantum fields without the need of projective measurements, which are always ill defined in quantum field theory. Inspired by interferometry schemes, we propose a work distribution that generalizes the two-point measurement scheme employed in quantum thermodynamics to the case of quantum fields and avoids the use of projective measurements. The distribution is calculated for local unitary processes performed on Kubo-Martin-Schwinger (thermal) states of scalar fields. Crooks theorem and the Jarzynski equality are shown to be satisfied for a family of spatiotemporally localized unitaries, and some features of the resulting distributions are studied as functions of temperature and the degree of localization of the unitary operation. We show how the work fluctuations become much larger than the average as the process becomes more localized in both time and space.

10.
Virus Res ; 266: 1-14, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30930201

RESUMO

Exosomes are endocytic origin small-membrane vesicles secreted to the extracellular space by most cell types. Exosomes released from virus infected-cells can mediate the cell-to-cell communication to promote or modulate viral transmission. Dengue virus (DENV) is an arbovirus transmitted by Aedes mosquitoes bite to humans. Interestingly, the role of exosomes during the DENV infection in mammalian cells has already been described. However, little is known about exosomes derived from infected mosquito cells. Thus, the exosomes released from DENV-infected C6/36 cells were isolated, purified and analyzed using an antibody against the tetraspanin CD9 from human that showed cross-reactivity with the homologs to human CD9 found in Aedes albopictus (AalCD9). The exosomes from DENV infected cells were larger than the exosomes secreted from uninfected cells, contained virus-like particles, and they were able to infect naïve C6/36 cells, suggesting that exosomes are playing a role in virus dissemination.


Assuntos
Vírus da Dengue/fisiologia , Exossomos/metabolismo , Exossomos/virologia , Mosquitos Vetores/virologia , Aedes , Animais , Linhagem Celular , Dengue/metabolismo , Dengue/virologia , Difusão Dinâmica da Luz , Exossomos/imunologia , Humanos , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/imunologia , Proteínas de Insetos/metabolismo , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Mosquitos Vetores/classificação , Mosquitos Vetores/genética , Mosquitos Vetores/metabolismo , Filogenia , Tetraspaninas/química , Tetraspaninas/genética , Tetraspaninas/imunologia , Tetraspaninas/metabolismo , Replicação Viral
11.
Pharm Dev Technol ; 24(6): 751-760, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30845867

RESUMO

Methods for nanoparticles preparation often employ organic solvents in order to solubilize the non-polar constituents of the final nanostructures. In the research process, nanoparticles are assayed as aqueous suspensions in several cases, so that an excessive residual concentration of the organic solvent needs to be avoided since may lead to undesired secondary effects during biological tests. Despite the importance, residual solvent concentration is rarely determined, making necessary the development of quantification methods suitable for this purpose. Acetone is frequently used in drug delivery systems preparation, being capable to exert significant toxicities both, in vitro and in vivo. Thus, a simple and inexpensive UV-Vis spectrophotometric method is proposed to directly determine acetone from nanoparticles suspensions employing its reaction with vanillin. Central composite designs were employed to correct and optimize the quantification method, which was then validated according to international guidelines. The optimized method resulted accurate, precise, and linear in the range of 10-50 µg/mL, with an R2 of 0.998 and limits of detection and quantification of 2.6 and 7.8 µg/mL, respectively. The effect of several surfactants employed during nanoparticles preparation was not detrimental to the method. The proposed procedure can be successfully applied to directly quantify acetone from nanoparticles suspensions.


Assuntos
Acetona/análise , Portadores de Fármacos/química , Nanopartículas/química , Sistemas de Liberação de Medicamentos , Solventes/análise , Espectrofotometria Ultravioleta
12.
Physiol Mol Biol Plants ; 24(6): 1185-1201, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30425433

RESUMO

The root bark of Semialarium mexicanum (Miers) Mennega (cancerina) is traditionally used in Mexico to treat cancer. However, there are no studies supporting its use. We evaluated whether S. mexicanum root bark induces cytotoxicity in breast cancer cells to determine if it has potential applications in the treatment of this disease. Extracts of S. mexicanum root bark in petroleum ether, ethanol, and water were obtained by ultrasound-assisted extraction. MTT and WST-1 assays were used to evaluate the cytotoxicity of the extracts toward breast cancer cells (MDA-MB-231 and MCF7), non-tumorigenic breast-derived cells (MCF 10A), and peripheral blood mononuclear cells (PBMCs). For the extract with greatest cytotoxicity, induction of apoptosis and oxidative stress were determined using flow cytometry. The extract was fractionated, and the cytotoxicity of its fractions was evaluated with the four cell types. The fractions were also analyzed by HPLC. Only the petroleum ether extract was cytotoxic for all cell types (MDA-MB-231 > MCF 10A/MCF7 > PBMCs). Cell death occurred by apoptosis, which could be associated with the induction of oxidative stress. Two fractions that were highly cytotoxic for breast cancer cells were obtained from this extract (IC50 ≤ 4.15 µg/mL for the most active fraction at 72 h). The MCF 10A cells were less affected, while PBMCs were not affected after 72 h of treatment. Pristimerin was identified in both fractions and may be partially responsible for the cytotoxic effect. These results suggest that S. mexicanum root bark has a potential application in breast cancer treatment.

13.
Phys Rev Lett ; 119(5): 050502, 2017 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-28949719

RESUMO

We propose a method for increasing the purity of interacting quantum systems that takes advantage of correlations present due to the internal interaction. In particular, when this interaction is sufficiently strong, we show that by using the system's quantum correlations one can achieve cooling beyond established limits of previous conventional algorithmic cooling proposals which assume no interaction.

14.
J Biomater Sci Polym Ed ; 27(3): 218-34, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26540350

RESUMO

Silver nanoparticles (AgNPs) induce diverse cell-death mechanisms, similar to those promoted by anticancer chemotherapeutics; however, they have not been tested in vivo because their action is not limited to cancer cells. Therefore, in vivo evaluations of their effectiveness should be developed with targeting systems. Breast cancer shows changes in the sugar expression patterns on cell surfaces, related to cancer progression and metastases; those changes have been identified previously by the specific binding of soybean agglutinin (SBA). Here is proposed the use of SBA to target the AgNP activity in breast cancer. For that, the present work reports the synthesis of AgNPs (3.89 ± 0.90 nm) through the polyol method, the generation of AgNP nanocarriers, and the bioconjugation protocol of the nanocarrier with SBA. The free AgNPs, the AgNP nanocarriers, and the SBA-bioconjugated AgNP nanocarriers were tested for cytotoxicity in breast cancerous (MDA-MB-231and MCF7) and non cancerous (MCF 10A) cells, using the MTT assay. AgNPs demonstrated cytotoxic activity in vitro, the non cancerous cells (MCF 10A) being more sensible than the cancerous cells (MDA-MB-231 and MCF7) showing LD(50) values of 128, 205, and 319 µM Ag, respectively; the nanoencapsulation decreased the cytotoxic effect of AgNPs in non cancerous cells, maintaining or increasing the effect on the cancer-derived cells, whereas the SBA-bioconjugation allowed AgNP cytotoxic activity with a similar behavior to the nanocarriers. Future experiments need to be developed to evaluate the targeting effect of the SBA-bioconjugated AgNP nanocarriers to study their functionality in vivo.


Assuntos
Antineoplásicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Portadores de Fármacos , Nanopartículas Metálicas , Lectinas de Plantas/administração & dosagem , Compostos de Prata , Proteínas de Soja/administração & dosagem , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Difusão Dinâmica da Luz , Humanos , Hidrodinâmica , Concentração de Íons de Hidrogênio , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Paclitaxel/administração & dosagem , Polietilenoglicóis/administração & dosagem , Compostos de Prata/administração & dosagem , Compostos de Prata/síntese química , Compostos de Prata/química , Análise Espectral Raman
15.
Biomed Opt Express ; 6(10): 3898-906, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26504640

RESUMO

In this study the encapsulation of core shell carboxyl CdSe/ZnS quantum dots (QDs) by phospholipids liposome complexes is presented. It makes the quantum dots water soluble and photo-stable. Fluorescence self-quenching of the QDs inside the liposomes was observed. Therefore, the thermal lens microscopy (TLM) was found to be an useful tool for measuring the encapsulation efficiency of the QDs by the liposomes, for which an optimum value of 36% was determined. The obtained limit of detection (LOD) for determining QDs concentration by TLM was 0.13 nM. Moreover, the encapsulated QDs showed no prominent cytotoxicity toward Breast cancer cells line MDA-MB-231. This study was supported by UV-visible spectroscopy, high resolution transmission electron microscopy (HRTEM) and dynamic light scattering measurements (DLS).

16.
Phys Rev Lett ; 115(3): 031301, 2015 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-26230781

RESUMO

We analyze how preexisting entanglement between two Unruh-DeWitt particle detectors evolves when one of the detectors falls through a Rindler firewall in (1+1)-dimensional Minkowski space. The firewall effect is minor and does not wash out the detector-detector entanglement, in some regimes even preserving the entanglement better than Minkowski vacuum. The absence of cataclysmic events should continue to hold for young black hole firewalls. A firewall's prospective ability to resolve the information paradox must hence hinge on its detailed gravitational structure, presently poorly understood.

17.
J Food Sci Technol ; 52(7): 4066-77, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26139872

RESUMO

A central composite design using RMS (Response Surface Methodology) successfully described the effect of independent variables (feed moisture, die temperature and soybean proportion) on the specific parameters of product quality as expansion index (EI), water absorption index (WAI), water solubility index (WSI) and total color difference (ΔE) studied. The regression model indicated that EI, WAI, WSI and ΔE were significant (p < 0.05) with coefficients of determination (R(2)) of 0.7371, 0.7588, 0.7622, 0.8150, respectively. The optimized processing conditions were obtained with 25.8 % feed moisture, 160 °C die temperature and 58 %/42 % soybean/corn proportion. It was not found statistically changes in amino acid profile due to extrusion process. The electrophoretic profile of extruded soybean/corn mix presented low intensity molecular weight bands, compared to the unprocessed sample. The generation of low molecular weight polypeptides was associated to an increased in In vitro protein digestibility (IVPD) of the extrudate. The FTIR spectra of the soybean/corn mix before and after extrusion showed that the α-helix structure remained unchanged after extrusion. However, the band associated with ß-sheet structure showed to be split into two bands at 1624 and 1640 cm(-1) . The changes in the ß-sheet structures may be also associated to the increased in IVPD in the extruded sample.

18.
Phys Rev Lett ; 114(14): 141103, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25910106

RESUMO

We analyze the implications of the violations of the strong Huygen's principle in the transmission of information from the early Universe to the current era via massless fields. We show that much more information reaches us through timelike channels (not mediated by real photons) than is carried by rays of light, which are usually regarded as the only carriers of information.

19.
Phys Rev Lett ; 114(11): 110505, 2015 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-25839251

RESUMO

We show that it is possible to use a massless field in the vacuum to communicate in such a way that the signal travels arbitrarily slower than the speed of light and such that no energy is transmitted from the sender to the receiver. Instead, the receiver has to supply a signal-dependent amount of work to switch his detector on and off. This type of communication is related to Casimir-like interactions, and it is made possible by dimension-and curvature-dependent subtleties of Huygens' principle.

20.
J Agric Food Chem ; 61(49): 11995-2004, 2013 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-24168389

RESUMO

Betalains were extracted and analyzed from Opuntia joconostle (the prickly pear known as xoconostle in Mexico). For the extraction, two solvent systems were used, methanol/water and ethanol/water. A three-variable Box-Behnken statistical design was used for extraction: solvent concentration (0-80%, v/v), temperature (5-30 °C), and treatment time (10-30 min). The extraction and stability of betalains from xoconostle were studied using response surface methodology (RSM). Techniques such as UV-vis, column chromatography, and HPLC were employed for the separation and analysis of the main pigments present in the extracts. Maximum pigment concentration (92 mg/100 g of fruit) was obtained at a temperature of 15 °C and a time of 10 min for methanol/water (20:80), whereas maximum stability of the pigment was observed at pH 5 and a temperature of 25 °C. HPLC chromatograms showed the main betalains of the xoconostle characterized were betalain, betanidin, and isobetalain.


Assuntos
Betalaínas/química , Betalaínas/isolamento & purificação , Frutas/química , Opuntia/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Cromatografia , Cromatografia Líquida de Alta Pressão
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...