Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
J Photochem Photobiol B ; 256: 112943, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38788534

RESUMO

With the rapid development of nanotechnology, various functional nanomaterials have shown exciting potential in biomedical areas such as drug delivery, antitumor, and antibacterial therapy. These nanomaterials improve the stability and selectivity of loaded drugs, reduce drug-induced side effects, realize controlled and targeted drug release, and increase therapeutic efficacy. The increased resistance to antifungal microbicides in medical practice and their side effects stimulate interest in new therapies, such as Photodynamic Therapy (PDT), which do not generate resistance in microorganisms and effectively control the pathology. The present study aimed to evaluate, in vitro, the efficacy of photodynamic therapy on Candida albicans using 1,9-Dimethyl-Methylene Blue (DMMB) as photosensitizer, red LED (λ630), and nanoencapsulation of DMMB (RL-NPs/DMMB) using rhamnolipids produced by Pseudomonas aeruginosa to evaluate if there is better performance of DMMB + RL particles compared to DMMB alone via the characterization of DMMB + RL and colony forming count. The tests were carried out across six experimental groups (Control, DMMB, RL-NPs, RL-NPs/DMMB, PDT and PDT + RL-NPs/DMMB) using in the groups with nanoparticles, DMMB (750 ng/mL) encapsulated with rhamnolipids in a 1:1 ratio, the light source consisted of a prototype built with a set of red LEDs with an energy density of 20 J/cm2. The results showed that applying PDT combined with encapsulation (RL-NPs/DMMB) was a more practical approach to inhibit Candida albicans (2 log reduction) than conventional applications, with a possible clinical application protocol.


Assuntos
Candida albicans , Glicolipídeos , Azul de Metileno , Nanopartículas , Fotoquimioterapia , Fármacos Fotossensibilizantes , Pseudomonas aeruginosa , Candida albicans/efeitos dos fármacos , Glicolipídeos/química , Glicolipídeos/farmacologia , Azul de Metileno/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Nanopartículas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Antifúngicos/química , Antifúngicos/farmacologia , Composição de Medicamentos
2.
Sensors (Basel) ; 21(24)2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34960513

RESUMO

The densification of multiple wireless communication systems that coexist nowadays, as well as the 5G new generation cellular systems advent towards the millimeter wave (mmWave) frequency range, give rise to complex context-aware scenarios with high-node density heterogeneous networks. In this work, a radiofrequency electromagnetic field (RF-EMF) exposure assessment from an empirical and modeling approach for a large, complex indoor setting with high node density and traffic is presented. For that purpose, an intensive and comprehensive in-depth RF-EMF E-field characterization study is provided in a public library study case, considering dense personal mobile communications (5G FR2 @28 GHz) and wireless 802.11ay (@60 GHz) data access services on the mmWave frequency range. By means of an enhanced in-house deterministic 3D ray launching (3D-RL) simulation tool for RF-EMF exposure assessment, different complex heterogenous scenarios of high complexity are assessed in realistic operation conditions, considering different user distributions and densities. The use of directive antennas and MIMO beamforming techniques, as well as all the corresponding features in terms of radio wave propagation, such as the body shielding effect, dispersive material properties of obstacles, the impact of the distribution of scatterers and the associated electromagnetic propagation phenomena, are considered for simulation. Discussion regarding the contribution and impact of the coexistence of multiple heterogeneous networks and services is presented, verifying compliance with the current established international regulation limits with exposure levels far below the aforementioned limits. Finally, the proposed simulation technique is validated with a complete empirical campaign of measurements, showing good agreement. In consequence, the obtained datasets and simulation estimations, along with the proposed RF-EMF simulation tool, could be a reference approach for the design, deployment and exposure assessment of the current and future wireless communication technologies on the mmWave spectrum, where massive high-node density heterogeneous networks are expected.


Assuntos
Campos Eletromagnéticos , Exposição Ambiental , Comunicação , Ondas de Rádio , Tecnologia sem Fio
3.
Rev. bras. cir. cardiovasc ; Rev. bras. cir. cardiovasc;36(5): 677-684, Sept.-Oct. 2021. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1351657

RESUMO

Abstract Introduction: The growth Stimulation expressed gene 2 (ST2) (or interleukin 1 receptor-like 1, also known as IL1RL1) is considered a biomarker of poor prognosis in cardiovascular diseases. The aims of this study are to investigate ST2 in the pericardial fluid (PF) of coronary artery disease patients and to contribute to the understanding of the pathophysiology of coronary artery disease. Methods: 40 patients (blood plasma and PF) who underwent coronary artery bypass surgery and 40 controls (blood plasma only) were included in this study. Soluble ST2 (sST2) level was determined by enzyme-linked ımmunosorbent assay method in plasma and PF, and sST2 gene expression was determined by quantitative real-time polymerase chain reaction (QRT-PCR) method. Results: The sST2 level was found to be 44.89 ng/ml and 390.357 ng/ml in the control and patient groups' plasma, and 223.992 ng/ml in the PF of the patient group. An increase in sST2 level was detected in the patient group compared to the control group (P<0.001). The sST2 expression in plasma was higher in the patient group than in the control group. Additionally, sST2 was more expressed in the plasma of the patient group than PF (P<0.001). Conclusion: The fact that sST2 was detected for the first time in a high level in PF showed that this biomarker was closely related with the heart and strengthened its potential to be used as a biomarker. Therefore, sST2 can contribute to the understanding of the pathophysiology of coronary artery disease.


Assuntos
Humanos , Doença da Artéria Coronariana , Líquido Pericárdico , Prognóstico , Biomarcadores , Ponte de Artéria Coronária
4.
Braz J Cardiovasc Surg ; 36(5): 677-684, 2021 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-33355808

RESUMO

INTRODUCTION: The growth Stimulation expressed gene 2 (ST2) (or interleukin 1 receptor-like 1, also known as IL1RL1) is considered a biomarker of poor prognosis in cardiovascular diseases. The aims of this study are to investigate ST2 in the pericardial fluid (PF) of coronary artery disease patients and to contribute to the understanding of the pathophysiology of coronary artery disease. METHODS: 40 patients (blood plasma and PF) who underwent coronary artery bypass surgery and 40 controls (blood plasma only) were included in this study. Soluble ST2 (sST2) level was determined by enzyme-linked immunosorbent assay method in plasma and PF, and sST2 gene expression was determined by quantitative real-time polymerase chain reaction (QRT-PCR) method. RESULTS: The sST2 level was found to be 44.89 ng/ml and 390.357 ng/ml in the control and patient groups' plasma, and 223.992 ng/ml in the PF of the patient group. An increase in sST2 level was detected in the patient group compared to the control group (P<0.001). The sST2 expression in plasma was higher in the patient group than in the control group. Additionally, sST2 was more expressed in the plasma of the patient group than PF (P<0.001). CONCLUSION: The fact that sST2 was detected for the first time in a high level in PF showed that this biomarker was closely related with the heart and strengthened its potential to be used as a biomarker. Therefore, sST2 can contribute to the understanding of the pathophysiology of coronary artery disease.


Assuntos
Doença da Artéria Coronariana , Líquido Pericárdico , Biomarcadores , Ponte de Artéria Coronária , Humanos , Prognóstico
5.
Data Brief ; 29: 105311, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32211458

RESUMO

Data described in this article are related to the research article entitled "Amphotericin B-loaded Eudragit RL100 nanoparticles coated with hyaluronic acid (AMP EUD nanoparticles/HA) for the treatment of vulvovaginal candidiasis" [1]. In this work, we report original data on the statistical experimental design to formulate uncoated AMP EUD nanoparticles, data on the validation of spectrophotometric method to quantify the AMP released from uncoated EUD nanoparticles and coated with HA to obtain the in vitro drug release profiles as well as the drug encapsulation efficiency. In addition, we describe original data on characterization, including diameter size, polydispersity index, zeta potential, FTIR, DSC/TG, and XRD; data on diameter of in vitro inhibition halos of Candida albicans; and on the vaginal burden of infected animals treated with uncoated AMP EUD nanoparticles and AMP EUD nanoparticles/HA. Finally, different histological sections of endocervix collected from treated and untreated animals were inserted into this manuscript.

6.
Toxicol Rep ; 6: 616-624, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31316897

RESUMO

Fruit peels of Plinia cauliflora (Mart.) Kausel are widely used in Brazilian traditional medicine, but no studies have proved the safety of its pharmacological effects on the respiratory, cardiovascular, and central nervous systems. The present study assessed the safety pharmacology of P. cauliflora in New Zealand rabbits. First, an ethanol extract (EEPC) was selected for the pharmacological experiments and chemical characterization. Then, different groups of rabbits were orally treated with EEPC (200 and 2000 mg/kg) or vehicle. Acute behavioral and physiological alterations in the modified Irwin test, respiratory rate, arterial blood gas, and various cardiovascular parameters (i.e., heart rate, blood pressure, and electrocardiography) were evaluated. The main secondary metabolites that were identified in EEPC were ellagic acid, gallic acid, O-deoxyhexosyl quercetin, and the anthocyanin O-hexosyl cyanidin. No significant behavioral or physiological changes were observed in any of the groups. None of the doses of EEPC affected respiratory rate or arterial blood gas, with no changes on blood pressure or electrocardiographic parameters. The present study showed that EEPC did not cause any significant changes in respiratory, cardiovascular, or central nervous system function. These data provide scientific evidence of the effects of this species and important safety data for its clinical use.

7.
Colloids Surf B Biointerfaces ; 177: 169-177, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30731393

RESUMO

Benznidazole (BNZ) is the drug of choice for the treatment of Chagas disease in many countries. However, its low water solubility produces low and/or variable oral bioavailability. Thus, the aim of this work was to formulate micro- and nanoparticles based on Eudragit® RS PO and Eudragit® RL PO as a convenient approach to increase the dissolution rate of BNZ. The microparticles were obtained by means of spray-drying process while the nanoparticles were prepared through the nanoprecipitation technique and further freeze-drying. The results indicated that nanoparticles were obtained in 86% yield while microparticles were obtained in 68% yield. In both cases, the encapsulation efficiency of particles was greater than 78% while drug loading capacity was nearly 24% w/w and 18% w/w, after spray-drying and freeze-drying procedures, respectively. Images of scanning electron microscopy showed that the particles obtained by spray-drying and freeze-drying were in the micrometer and nanometer scale, respectively. FT-IR spectra of BNZ-loaded particles obtained by both methods showed characteristic bands of BNZ confirming that part of drug remained on their surface. Thermal analysis revealed that the drug crystallinity after both methods decreased. Physical stability evaluation of the nanoparticles confirmed that Pluronic® F68 was suitable to keep the particles size in a range of 300 nm after 70 days storage at 4 ± 2 °C. In-vitro release studies showed increased dissolution rate of drug from the particles obtained by both methods respect to untreated BNZ. The kinetics of drug release in acid media followed the Higuchi kinetics indicating drug diffusion mechanism from particles.


Assuntos
Doença de Chagas/tratamento farmacológico , Imunossupressores/química , Imunossupressores/uso terapêutico , Nanopartículas/química , Nitroimidazóis/química , Nitroimidazóis/uso terapêutico , Criança , Liberação Controlada de Fármacos , Humanos , Hidrodinâmica , Imunossupressores/síntese química , Cinética , Nitroimidazóis/síntese química , Tamanho da Partícula , Propriedades de Superfície
8.
Braz J Infect Dis ; 22(6): 477-486, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30586543

RESUMO

Antiviral drug resistance is the most important factor contributing to treatment failure using nucleos(t)ide analogs such as lamivudine for chronic infection with hepatitis B virus (HBV). Development of a system supporting efficient replication of clinically resistant HBV strains is imperative, and new antiviral drugs are needed urgently to prevent selection of drug-resistant HBV mutants. A novel fluorinated cytidine analog, NCC (N-cyclopropyl-4'-azido-2'-deoxy-2'-fluoro-ß-d-cytidine), was recently shown to strongly inhibit human HBV in vitro and in vivo. This study was designed to evaluate the antiviral activity of NCC against lamivudine-resistant HBV. We generated a stable cell line encoding the major pattern of lamivudine-resistant mutations rtL180M/M204V and designated it "HepG2.RL1". Immuno-transmission electron microscopic examination and enzyme-linked immunosorbent assay were used to detect secretion of HBV-specific particles and antigens. Quantification of extracellular DNA and intracellular DNA of HepG2.RL1 cells by quantitative real-time polymerase chain reaction revealed >625-fold and >5556-fold increases in the 50% inhibitory concentration of lamivudine, respectively, compared with that for the wild-type virus. The results showed that NCC inhibited DNA replication and HBeAg production in wild-type or lamivudine-resistant HBV in a dose-dependent manner. In conclusion, screening for antiviral compounds active against lamivudine-resistant HBV can be carried out with relative ease using hepG2.RL1 cells. NCC is a potential antiviral agent against wild-type HBV and clinical lamivudine-resistant HBV and deserves evaluation for the treatment of HBV infection.


Assuntos
Antivirais/farmacologia , Citidina/análogos & derivados , Farmacorresistência Viral/efeitos dos fármacos , Vírus da Hepatite B/efeitos dos fármacos , Lamivudina/farmacologia , Replicação Viral/efeitos dos fármacos , Linhagem Celular , DNA Viral/química , Feminino , Vírus da Hepatite B/isolamento & purificação , Vírus da Hepatite B/fisiologia , Hepatócitos/virologia , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação
9.
Braz. j. infect. dis ; Braz. j. infect. dis;22(6): 477-486, Nov.-Dec. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-984016

RESUMO

ABSTRACT Antiviral drug resistance is the most important factor contributing to treatment failure using nucleos(t)ide analogs such as lamivudine for chronic infection with hepatitis B virus (HBV). Development of a system supporting efficient replication of clinically resistant HBV strains is imperative, and new antiviral drugs are needed urgently to prevent selection of drug-resistant HBV mutants. A novel fluorinated cytidine analog, NCC (N-cyclopropyl-4′-azido-2′-deoxy-2′-fluoro-β-d-cytidine), was recently shown to strongly inhibit human HBV in vitro and in vivo. This study was designed to evaluate the antiviral activity of NCC against lamivudine-resistant HBV. We generated a stable cell line encoding the major pattern of lamivudine-resistant mutations rtL180M/M204V and designated it "HepG2.RL1". Immuno-transmission electron microscopic examination and enzyme-linked immunosorbent assay were used to detect secretion of HBV-specific particles and antigens. Quantification of extracellular DNA and intracellular DNA of HepG2.RL1 cells by quantitative real-time polymerase chain reaction revealed >625-fold and >5556-fold increases in the 50% inhibitory concentration of lamivudine, respectively, compared with that for the wild-type virus. The results showed that NCC inhibited DNA replication and HBeAg production in wild-type or lamivudine-resistant HBV in a dose-dependent manner. In conclusion, screening for antiviral compounds active against lamivudine-resistant HBV can be carried out with relative ease using hepG2.RL1 cells. NCC is a potential antiviral agent against wild-type HBV and clinical lamivudine-resistant HBV and deserves evaluation for the treatment of HBV infection.


Assuntos
Humanos , Feminino , Pessoa de Meia-Idade , Antivirais/farmacologia , Replicação Viral/efeitos dos fármacos , Vírus da Hepatite B/efeitos dos fármacos , Lamivudina/farmacologia , Citidina/análogos & derivados , DNA Viral/química , Testes de Sensibilidade Microbiana , Linhagem Celular , Vírus da Hepatite B/isolamento & purificação , Vírus da Hepatite B/fisiologia , Hepatócitos/virologia , Farmacorresistência Viral/efeitos dos fármacos , Mutação
10.
Free Radic Biol Med ; 65: 1078-1089, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23999506

RESUMO

The chemotherapeutic isothiocyanate sulforaphane (SFN) was early linked to anticarcinogenic and antiproliferative activities. Soon after, this compound, derived from cruciferous vegetables, became an excellent and useful trial for anti-cancer research in experimental models including growth tumor, metastasis, and angiogenesis. Many subsequent reports showed modifications in mitochondrial signaling, functionality, and integrity induced by SFN. When cytoprotective effects were found in toxic and ischemic insult models, seemingly contradictory behaviors of SFN were discovered: SFN was inducing deleterious changes in cancer cell mitochondria that eventually would carry the cell to death via apoptosis and also was protecting noncancer cell mitochondria against oxidative challenge, which prevented cell death. In both cases, SFN exhibited effects on mitochondrial redox balance and phase II enzyme expression, mitochondrial membrane potential, expression of the family of B cell lymphoma 2 homologs, regulation of proapoptotic proteins released from mitochondria, activation/inactivation of caspases, mitochondrial respiratory complex activities, oxygen consumption and bioenergetics, mitochondrial permeability transition pore opening, and modulation of some kinase pathways. With the ultimate findings related to the induction of mitochondrial biogenesis by SFN, it could be considered that SFN has effects on mitochondrial dynamics that explain some divergent points. In this review, we list the reports involving effects on mitochondrial modulation by SFN in anti-cancer models as well as in cytoprotective models against oxidative damage. We also attempt to integrate the data into a mechanism explaining the various effects of SFN on mitochondrial function in only one concept, taking into account mitochondrial biogenesis and dynamics and making a comparison with the theory of reactive oxygen species threshold of cell death. Our interest is to achieve a complete view of cancer and protective therapies based on SFN that can be extended to other chemotherapeutic compounds with similar characteristics. The work needed to test this hypothesis is quite extensive.


Assuntos
Antioxidantes/farmacologia , Isotiocianatos/farmacologia , Mitocôndrias/fisiologia , Animais , Apoptose , Humanos , Mitocôndrias/efeitos dos fármacos , Renovação Mitocondrial/efeitos dos fármacos , Neoplasias/metabolismo , Estresse Oxidativo , Sulfóxidos
11.
J Steroid Biochem Mol Biol ; 138: 174-82, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23727130

RESUMO

Primates secrete large amounts of the precursor steroid dehydroepiandrosterone (DHEA); in humans, its levels are low during childhood and start declining after the fourth decade. It has been postulated that the progressive decline in DHEA levels may be related with the severity of asthma associated with age. To determine whether DHEA may regulate the airway smooth muscle (ASM) activity, isolated tracheal rings with and without epithelium from male guinea pigs were isometrically recorded to characterize the response of ASM to DHEA at different concentrations on KCl- and carbachol (CCh)-induced contraction as well as on ovalbumin (OVA)-induced contraction in sensitized guinea pigs. Additionally, we used barometric plethysmography in sensitized guinea pigs in order to compare changes of the lung resistance increased by the antigen challenge to OVA in the absence and presence of different doses of DHEA. DHEA concentration-dependently abolished the contraction to KCl, CCh and OVA, and no differences were found in preparations with and without epithelium. DHEA-induced relaxation was not modified by the suppression of protein synthesis or transcription, pharmacological inhibition of nitric oxide (NO) synthase, nor by antagonist of ß2-adrenergic receptors or an inhibitor of the 3ß-HSD enzyme. Likewise, Ca(2+)-induced contraction in Ca(2+)-free depolarized tissues was antagonized by DHEA, and the contraction to the L-type voltage-dependent calcium channel activator (Bay K 8644) was inhibited by DHEA. Furthermore, DHEA prevented OVA-induced increases in lung resistance. These results indicate that DHEA-induced relaxation in ASM is a nongenomic (membrane) action and is not produced after its bioconversion. The data suggest that DHEA-induced relaxation is an epithelium- and NO-independent mechanism that involves a blockade of voltage-dependent calcium channels and possible non-selective cation channels.


Assuntos
Desidroepiandrosterona/farmacologia , Músculo Liso/efeitos dos fármacos , Animais , Asma , Espasmo Brônquico/prevenção & controle , Cobaias , Técnicas In Vitro , Masculino , Relaxamento Muscular/efeitos dos fármacos , Músculo Liso/fisiologia , Traqueia/efeitos dos fármacos , Traqueia/fisiologia
12.
Braz. j. pharm. sci ; 45(4): 829-840, Oct.-Dec. 2009. tab, ilus
Artigo em Inglês | LILACS | ID: lil-543679

RESUMO

The present study investigated a novel extended release system of promethazine hydrochloride (PHC) with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5), and in combination (0.5+1.5), using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Powder X-ray diffractometry (PXRD), Nuclear magnetic resonance (NMR), Scanning electron microscopy (SEM), as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2), double-distilled water and phosphate buffer (pH 7.4). Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5) for S100 and RL 100 exhibited a higher dissolution rate with 97.14 percent drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5) displayed extended release of drug for twelve hours with 96.87 percent release followed by zero order kinetics (r²= 0.9986).


O presente trabalho compreendeu estudo de um novo sistema de liberação prolongada de cloridrato de prometazina (PHC) com polímeros acrílicos Eudragit RL100 e Eudragit S100 em diferentes proporções em massa (1:1 e 1:5) e em combinação (0,5+1,5), utilizando técnicas de liofilização e de secagem por aspersão As dispersões sólidas foram caracterizadas por espectrofotometria no infravermelho por transformada de Fourier (FT-IR), calorimetria diferencial de varredura (DSC), difratometria de raios X (PXRD), Ressonância Magnética Nuclear (RMN), microscopia eletrônica de varredura (SEM) e, também, por estudos de solubilidade e de dissolução in vitro em HCl 0,1 N (pH 1,2), água bidestilada e tampão fosfato (pH 7,4). Realizaram-se, também, testes de adsorção da solução do fármaco nos polímeros sólidos. Desenvolveu-se sistema de dispersão sólida exclusiva dentro das cápsulas, que foi avaliado por meio de estudos de dissolução in vitro. Relacionou-se o desaparecimento progressivo de picos do fármaco em perfis termotrópicos de dispersões secas por spray à quantidade aumentada de polímero, enquanto os estudos de SEM sugeriram dispersão homogênea do fármaco no polímero. O Eudragit RL100 apresentou maior capacidade de adsorção do que o Eudragit S100 e, dessa forma, a combinação de (0,5+1,5) para S100 e para RL100 mostrou taxa de dissolução maior, com liberação de 94,17 por cento de fármaco em 12 horas. Entre as várias formulações, as cápsulas preparadas pela combinação de polímeros acrílicos utilizando secagem por aspersão (0,5+1,5) apresentou liberação prolongada do fármaco em 12 horas, com 96,78 por cento de liberação, seguindo cinética de ordem zero (r² = 0,9986).


Assuntos
Ácido Clorídrico/farmacocinética , Química Farmacêutica , Preparações de Ação Retardada , Polímeros/farmacocinética , Fenômenos de Química Orgânica , Prometazina/farmacocinética , Avaliação de Medicamentos , Liofilização , Preparações Farmacêuticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA