RESUMO
This study presents fibers based on methacrylic acid-methyl methacrylate (Eudragit L100) as Cu(II) adsorbents, resulting in antimicrobial complexes. Eudragit L100, an anionic copolymer synthesized by radical polymerization, was electrospun in dimethylformamide (DMF) and ethanol (EtOH). The electrospinning process was optimized through a 22-factorial design, with independent variables (copolymer concentration and EtOH/DMF volume ratio) and three repetitions at the central point. The smallest average fiber diameter (259 ± 53 nm) was obtained at 14% w/v Eudragit L100 and 80/20 EtOH/DMF volume ratio. The fibers were characterized using scanning electron microscopy (SEM), infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and differential scanning calorimetry (DSC). The pseudo-second-order mechanism explained the kinetic adsorption toward Cu(II). The fibers exhibited a maximum adsorption capacity (qe) of 43.70 mg/g. The DSC analysis confirmed the Cu(II) absorption, indicating complexation between metallic ions and copolymer networks. The complexed fibers showed a lower degree of swelling than the non-complexed fibers. The complexed fibers exhibited bacteriostatic activity against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. This study successfully optimized the electrospinning process to produce thin fibers based on Eudragit L100 for potential applications as adsorbents for Cu(II) ions in aqueous media and for controlling bacterial growth.
Assuntos
Cobre , Ácidos Polimetacrílicos , Cobre/química , Ácidos Polimetacrílicos/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Adsorção , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Metacrilatos/química , Cinética , Varredura Diferencial de Calorimetria , Testes de Sensibilidade MicrobianaRESUMO
This review aims to investigate the different levels of vitamin D and its role in muscle strength in healthy children and non-athletes. A search conducted in three databases (PubMed, Scopus, and Psycinfo) resulted in 655 articles, which were systematically analyzed and selected based on the following criteria: (a) original cross-sectional studies and clinical trials; (b) healthy children aged 5-11 years; (c) no language restriction or year of publication; and (d) studies that assessed the possible relationship between vitamin D levels and muscle strength. Six studies were included because they met all the inclusion criteria. According to the findings of this review, factors such as sex, skin color, and vitamin D supplementation early in life modulate the levels of vitamin D in the body, and there is a relationship between muscle strength and vitamin D levels. Interestingly, vitamin D supplementation is not always significantly associated with increased muscle grip strength. However, there is a scarcity of studies that aim to analyze the possible effects of different levels of vitamin D on muscle function and neuromuscular variables in physically inactive children and non-athletes without previously diagnosed disease. Further studies are warranted in the future to address the gap in the literature.
Assuntos
Deficiência de Vitamina D , Vitamina D , Criança , Estudos Transversais , Suplementos Nutricionais , Força da Mão , Humanos , Força Muscular , VitaminasRESUMO
This review aims to investigate the different levels of vitamin D and its role in muscle strength in healthy children and non-athletes. A search conducted in three databases (PubMed, Scopus, and Psycinfo) resulted in 655 articles, which were systematically analyzed and selected based on the following criteria: (a) original cross-sectional studies and clinical trials; (b) healthy children aged 5-11 years; (c) no language restriction or year of publication; and (d) studies that assessed the possible relationship between vitamin D levels and muscle strength. Six studies were included because they met all the inclusion criteria. According to the findings of this review, factors such as sex, skin color, and vitamin D supplementation early in life modulate the levels of vitamin D in the body, and there is a relationship between muscle strength and vitamin D levels. Interestingly, vitamin D supplementation is not always significantly associated with increased muscle grip strength. However, there is a scarcity of studies that aim to analyze the possible effects of different levels of vitamin D on muscle function and neuromuscular variables in physically inactive children and non-athletes without previously diagnosed disease. Further studies are warranted in the future to address the gap in the literature.
Assuntos
Humanos , Criança , Vitamina D , Deficiência de Vitamina D , Vitaminas , Estudos Transversais , Força da Mão , Suplementos Nutricionais , Força MuscularRESUMO
Conventional strategies (Turkevich's, and modified Turkevich's methods) often synthesize gold nanoparticles (AuNPs). These pathways produce AuNPs using toxic chemistries to reduce Au(III) and stabilize Au(0) atoms upon the AuNP surfaces. To overcome the disadvantages of conventional approaches, chitosan and chitosan-based materials associate with Au(III) to produce composites. Chitosan and derivatives reduce Au(III) and stabilize AuNPs, promoting biocompatibility to the composites, following approaches in-situ. In this review, we report methods to develop chitosan/AuNPs-based composites. The main criticism is about the mechanism of composite formation. Also, we highlight applications of chitosan/AuNPs-based devices in the biomedical arena. We report the synthesis of biosensors, drug delivery devices, scaffolds, antimicrobial coatings, and others. The major criticism is concerning the material design and the lack of data regarding the composite biocompatibility. We support a critical viewpoint.
Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Ouro/química , Nanopartículas Metálicas/química , Animais , Pesquisa Biomédica/métodos , HumanosRESUMO
This study reports the synthesis, characterization and biological properties of films based on poly(vinyl alcohol) (PVA) and a cationic tannin polymer derivative (TN). Films are obtained from polymeric blends by tuning the PVA/TN weight ratios. The materials are characterized through infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, mechanical analyses, and scanning electron microscopy. More hydrophilic surfaces are created by modulating the PVA and TN concentrations in the blends. Disintegration tests showed that the films present durability in phosphate buffer (pH 7.4) and low stability in simulated gastric fluid (pH 1.2). The film created at 90/10 PVA/TN weight ratio and crosslinked at 109 PVA/glutaraldehyde molar ratio (sample PVA10/TN10) supports the attachment and proliferation of bone marrow mesenchymal stem cells after 7 days of culture. The scaffolding capacity of the PVA10/TN10 surface is compared with titanium, one of the most important biomedical materials used in bone replacements. Also, the PVA/TN films exhibited cytocompatibility, antioxidant and antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. These properties make PVA/TN films are candidates for biomedical applications in the tissue engineering field.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Materiais Biocompatíveis/química , Taninos/farmacocinética , Animais , Antibacterianos/química , Antioxidantes/farmacocinética , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Reagentes de Ligações Cruzadas/química , Glutaral/química , Hidrogéis/síntese química , Hidrogéis/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Masculino , Teste de Materiais , Células-Tronco Mesenquimais/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Álcool de Polivinil/química , Pseudomonas aeruginosa/efeitos dos fármacos , Ratos Wistar , Staphylococcus aureus/efeitos dos fármacos , Taninos/químicaRESUMO
Introduction. Nosocomial transmission of Mycobacterium tuberculosis is an important health issue and the detection of tuberculosis (TB) cases is the main tool for controlling this disease.Aim. We aimed to assess the possible occurrence of nosocomial transmission of M. tuberculosis in a reference hospital for HIV/AIDS patients and evaluate both the performance of the Xpert MTB/RIF (Xpert) platform and drug resistance profiles.Methodology. We evaluated the performance of the Xpert platform. Samples that tested positive on the BACTEC MGIT 320 (MGIT320) platform were submitted for genotyping and drug susceptibility testing.Results. In this study, pulmonary and extrapulmonary samples from 407 patients were evaluated, and among these, 15.5â% were diagnosed with TB by the MGIT320 platform, with a TB/HIV coinfection rate of 52.4â%. The Xpert platform gave positive results for TB for 11 samples with negative results on the MGIT320 platform. In the genotyping results, 53.3â% of the strains clustered; of these strains, half were in two of the four clusters formed, and the patients had visited the hospital on the same day. Drug resistance was observed in 11.7â% of the strains.Conclusion. Putative nosocomial transmission of M. tuberculosis was detected, showing that genotyping is a powerful approach for understanding the dynamics of M. tuberculosis transmission, especially in a high-burden TB and HIV landscape.
Assuntos
Infecções por HIV/complicações , Técnicas de Diagnóstico Molecular/métodos , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Pulmonar/microbiologia , Síndrome da Imunodeficiência Adquirida/complicações , Antibióticos Antituberculose/farmacologia , Técnicas de Laboratório Clínico , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/microbiologia , Estudos Transversais , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Filogenia , Tuberculose , Tuberculose Pulmonar/diagnósticoRESUMO
Tuberculosis (TB) remains a major health problem within the Community of Portuguese Language Speaking Countries (CPLP). Despite the marked variation in TB incidence across its member-states and continued human migratory flux between countries, a considerable gap in the knowledge on the Mycobacterium tuberculosis population structure and strain circulation between the countries still exists. To address this, we have assembled and analysed the largest CPLP M. tuberculosis molecular and drug susceptibility dataset, comprised by a total of 1447 clinical isolates, including 423 multidrug-resistant isolates, from five CPLP countries. The data herein presented reinforces Latin American and Mediterranean (LAM) strains as the hallmark of M. tuberculosis populational structure in the CPLP coupled with country-specific differential prevalence of minor clades. Moreover, using high-resolution typing by 24-loci MIRU-VNTR, six cross-border genetic clusters were detected, thus supporting recent clonal expansion across the Lusophone space. To make this data available to the scientific community and public health authorities we developed CPLP-TB (available at http://cplp-tb.ff.ulisboa.pt), an online database coupled with web-based tools for exploratory data analysis. As a public health tool, it is expected to contribute to improved knowledge on the M. tuberculosis population structure and strain circulation within the CPLP, thus supporting the risk assessment of strain-specific trends.