RESUMO
OBJECTIVES: The glow discharge plasma (GDP) procedure has proven efficacy in grafting allylamine onto zirconia dental implant surfaces to enhance osseointegration. This study explored the enhancement of zirconia dental implant properties using GDP at different energy settings (25, 50, 75, 100, and 200 W) both in vitro and in vivo. MATERIALS AND METHODS: In vitro analyses included scanning electron microscopy, wettability assessment, energy-dispersive X-ray spectroscopy, and more. In vivo experiments involved implanting zirconia dental implants into rabbit femurs and later evaluation through impact stability test, micro-CT, and histomorphometric measurements. RESULTS: The results demonstrated that 25 and 50 W GDP allylamine grafting positively impacted MG-63 cell proliferation and increased alkaline phosphatase activity. Gene expression analysis revealed upregulation of OCN, OPG, and COL-I. Both 25 and 50 W GDP allylamine grafting significantly improved zirconia's surface properties (p < .05, p < .01, p < .001). However, only 25 W allylamine grafting with optimal energy settings promoted in vivo osseointegration and new bone formation while preventing bone level loss around the dental implant (p < .05, p < .01, p < .001). CONCLUSIONS: This study presents a promising method for enhancing Zr dental implant surface's bioactivity.
Assuntos
Alilamina , Implantes Dentários , Osseointegração , Osteogênese , Propriedades de Superfície , Zircônio , Zircônio/farmacologia , Animais , Osseointegração/efeitos dos fármacos , Coelhos , Osteogênese/efeitos dos fármacos , Alilamina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis , Microscopia Eletrônica de Varredura , Proliferação de Células/efeitos dos fármacos , Microtomografia por Raio-X , HumanosRESUMO
The emerging pathogen Trichophyton indotineae, often resistant to terbinafine (TRB), is known to cause severe dermatophytoses such as tinea corporis and tinea cruris. In order to achieve successful treatment for these infections, insight in the resistance profile of T. indotineae strains and rapid, reliable identification is necessary. In this research, a screening medium was tested on T. indotineae strains (n = 20) as an indication tool of TRB resistance. The obtained results were confirmed by antifungal susceptibility testing (AST) for TRB following the in vitro broth microdilution reference method. Additionally, AST was performed for eight other antifungal drugs: fluconazole, itraconazole, voriconazole, ketoconazole, griseofulvin, ciclopirox olamine, naftifine and amorolfine. Forty-five percent of the strains were confirmed to be resistant to terbinafine. The TRB resistant strains showed elevated minimal inhibitory concentration values for naftifine and amorolfine as well. DNA sequencing of the squalene epoxidase-encoding gene showed that TRB resistance was a consequence of missense point mutations in this gene, which led to amino acid substitutions F397L or L393F. MALDI-TOF MS was used as a quick, accurate identification tool for T. indotineae, as it can be challenging to distinguish it from closely related species such as Trichophyton mentagrophytes or Trichophyton interdigitale using morphological characteristics. While MALDI-TOF MS could reliably identify ≥ 95% of the T. indotineae strains (depending on the spectral library), it could not be used to successfully distinguish TRB susceptible from TRB resistant strains.
Assuntos
Alilamina/análogos & derivados , Antifúngicos , Arthrodermataceae , Terbinafina/farmacologia , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Trichophyton/genética , Arthrodermataceae/genética , Testes de Sensibilidade Microbiana , Farmacorresistência Fúngica/genéticaRESUMO
Adherence to antifungals is poor in high endemic regions where antifungal resistance is high. Poor readability of prescription/over-the-counter (OTC) antifungals may contribute to poor adherence, due to the patient not fully understanding the purpose, importance, and dosage of their antifungal medicine. As there are no reports on the readability of antifungals, this study examined the readability of patient-facing antifungal information. Antifungals (n = 16; five classes [allylamines, azoles, echinocandins, polyenes, and others-flucytosine and griseofulvin]) were selected. Readability of four sources of information, (i) summary of product characteristics, (ii) patient information leaflets (PILs), (iii) OTC patient information, and (iv) patient web-based information, was calculated using Readable software, to obtain readability scores [(i) Flesch Reading Ease [FRE], (ii) Flesch-Kinkaid Grade Level [FKGL], (iii) Gunning Fog Index, and (iv) Simple Measure of Gobbledygook (SMOG) Index) and text metrics [word count, sentence count, words/sentence, and syllables/word]. PILs, web-based resources, and OTC patient information had good readability (FRE mean ± sd = 52.8 ± 6.7, 58.6 ± 6.9, and 57.3 ± 7.4, respectively), just falling short of the ≥ 60 target. For FKGL (target ≤ 8.0), PILs, web-based resources, and OTC patient information also had good readability (mean ± sd = 8.5 ± 1.0, 7.2 ± 0.86, and 7.8 ± 0.1, respectively). Improved readability scores observed correlate with reduced words, words/sentence and syllables/word. Improving readability may lead to improved patient health literacy. Healthcare professionals, academics, and publishers preparing written materials regarding antifungals for the lay/patient community are encouraged to employ readability calculators to check the readability of their work, so that the final material is within recommended readability reference parameters, to support the health literacy of their patients/readers.
Yeast and mould infections can be difficult-to-treat, due to resistance. Our study shows that patient information on antifungals is fairly easy-to-read. Such information helps the patient know how best to take the medicine and help avoid resistance. Authors should always try to write clearly for patients.
Assuntos
Alilamina , Letramento em Saúde , Animais , Antifúngicos/uso terapêutico , Equinocandinas , Compreensão , Azóis , Polienos/uso terapêutico , Austrália , Reino UnidoRESUMO
Pigments produced by micro-organisms could contribute to their pathogenesis and resistance. The investigation into the red pigment of R. mucilaginosa and its ability to survive and resist has not yet been explored. This study aimed to investigate the survival and resistance of the R. mucilaginosa CQMU1 strain following inhibition of pigment production by naftifine and its underlying mechanism. The red-pigmented Rhodotorula mucilaginosa CQMU1 yeast was isolated from an infected toenail of a patient with onychomycosis. Cultivation of R. mucilaginosa in liquid and solid medium showed the effect of naftifine after treatment. Then, analysis of phagocytosis and tolerance to heat or chemicals of R. mucilaginosa was used to evaluate the survival and resistance of yeast to different treatments. Naftifine reversibly inhibited the pigmentation of R. mucilaginosa CQMU1 in solid and liquid media. Depigmented R. mucilaginosa CQMU1 showed increased susceptibility toward murine macrophage cells RAW264.7 and reduced resistance toward different types of chemicals, such as 1.5-M NaCl and 0.5% Congo red. Inhibition of pigment production by naftifine affected the survival and growth of R. mucilaginosa and its resistance to heat and certain chemicals. The results obtained could further elucidate the target of new mycosis treatment.
Assuntos
Alilamina , Rhodotorula , Humanos , Animais , Camundongos , Alilamina/farmacologiaRESUMO
Catalytic control of chemoselectivity is crucial in the synthesis of highly functionalized compounds. Although there are reports of efficient chemoselective reactions of alcohols and amines as nucleophiles, there are no reports of the chemoselective activation of alcohols and amines as electrophiles. In this study, highly O- and N-selective electrophilic activation of allylic alcohols and amines was achieved in Pd-catalyzed direct allylic alkylation. Allylamines were inherently more reactive than allylic alcohols (N-selectivity). On the other hand, the addition of catalytic amounts of 9-phenanthreneboronic acid preferentially activated allylic alcohols over allylamines (O-selectivity). Density functional theory (DFT) calculations suggested that the N-selectivity is due to the selective activation of allylic amines with ammonium cations, and boronate formation accelerates the activation of allylic alcohols.
Assuntos
Compostos Alílicos , Alilamina , Aminas , Paládio , Estrutura Molecular , Estereoisomerismo , Álcoois , Alquilação , CatáliseRESUMO
Cellular membranes are essential for compartmentalization, maintenance of permeability, and fluidity in all three domains of life. Archaea belong to the third domain of life and have a distinct phospholipid composition. Membrane lipids of archaea are ether-linked molecules, specifically bilayer-forming dialkyl glycerol diethers (DGDs) and monolayer-forming glycerol dialkyl glycerol tetraethers (GDGTs). The antifungal allylamine terbinafine has been proposed as an inhibitor of GDGT biosynthesis in archaea based on radiolabel incorporation studies. The exact target(s) and mechanism of action of terbinafine in archaea remain elusive. Sulfolobus acidocaldarius is a strictly aerobic crenarchaeon thriving in a thermoacidophilic environment, and its membrane is dominated by GDGTs. Here, we comprehensively analyzed the lipidome and transcriptome of S. acidocaldarius in the presence of terbinafine. Depletion of GDGTs and the accompanying accumulation of DGDs upon treatment with terbinafine were growth phase-dependent. Additionally, a major shift in the saturation of caldariellaquinones was observed, which resulted in the accumulation of unsaturated molecules. Transcriptomic data indicated that terbinafine has a multitude of effects, including significant differential expression of genes in the respiratory complex, motility, cell envelope, fatty acid metabolism, and GDGT cyclization. Combined, these findings suggest that the response of S. acidocaldarius to terbinafine inhibition involves respiratory stress and the differential expression of genes involved in isoprenoid biosynthesis and saturation.
Assuntos
Alilamina , Sulfolobus acidocaldarius , Terbinafina/farmacologia , Terbinafina/metabolismo , Sulfolobus acidocaldarius/genética , Sulfolobus acidocaldarius/metabolismo , Alilamina/metabolismo , Glicerol/metabolismo , Lipídeos de Membrana/metabolismo , Archaea/genéticaRESUMO
Dermatophytosis is a very common public health problem with high prevalence. Dermatophytes are a highly specialized set of filamentous fungi, which are adapted to keratinized tissues of humans and animals. Dermatophytosis is the most common fungal infection worldwide, affecting approximately 20-25% of the world's population. The etiological agents of dermatophytosis, called dermatophytes, change with geography and socioeconomic status. Trichophyton rubrum (T. rubrum) is the prime species for skin and nail infections followed by T. mentagrophytes/ T. interdigital complex. There is a shift from T. rubrum to T. mentagrophytes in India for superficial fungal infections. In order to deal with fungal infections, treatment strategies involve the use of systemic antifungals and/or topical antifungal agents. Naftifine is a synthetic allylamine antifungal first reported in 1974 and in 1985 became the first commercially available allylamine. The highly lipophilic nature of allylamine allows efficient penetration and reasonably high concentrations in the stratum corneum (SC) and hair follicles. Naftifine is fungicidal as well as fungistatic. The higher efficacy rates of allylamines over imidazoles for the treatment of fungal infections, even for months after cessation of treatment, is thought to be due to their fungicidal effect, as well as to potentially greater keratin binding and slower release from the SC. The effectiveness of naftifine is also demonstrated against various bacteria belonging to both gram-negative and gram-positive classes. The antiinflammatory property of naftifine has been reported in various preclinical studies where it has been shown to target the prostaglandin pathway. Naftifine 1 and 2% gel and cream is approved by The United States Food and Drug Administration (USFDA), recently naftifine has been approved in India by the Indian regulatory authority Drug Controller General of India (DCGI) for the treatment of dermatophytosis. Naftifine 2% also appears to be a promising treatment, requiring fewer applications than the 1% formulation. Naftifine appears to be effective in a single dose and has a shorter treatment duration than azoles. Naftifine demonstrated its efficacy and safety in various clinical studies of tinea infections. Naftifine offers a very useful and promising option for treating dermatophytosis.
Assuntos
Alilamina , Dermatomicoses , Tinha , Humanos , Alilamina/uso terapêutico , Alilamina/metabolismo , Pele , Dermatomicoses/tratamento farmacológico , Antifúngicos/uso terapêutico , Tinha/tratamento farmacológico , Tinha/metabolismoRESUMO
Allylamines are important building blocks in the synthesis of bioactive compounds. The direct coupling of allylic C-H bonds and commonly available amines is a major synthetic challenge. An allylic C-H amination of 1,4-dienes has been accomplished by palladium catalysis. With aromatic amines, branch-selective allylic aminations are favored to generate thermodynamically unstable Z-allylamines. In addition, more basic aliphatic cyclic amines can also engage in the reaction, but linear dienyl allylic amines are the major products.
Assuntos
Compostos Alílicos , Alilamina , Aminação , Paládio/química , Compostos Alílicos/química , Aminas/química , CatáliseRESUMO
The interaction between polyamines and phosphate species is found in a wide range of biological and abiotic systems, yielding crucial consequences that range from the formation of supramolecular colloids to structure determination. In this work, the occurrence of phosphate-amino interactions is evidenced from changes in the electronic response of graphene field effect transistors (gFETs). First, the surface of the transistors is modified with poly(allylamine), and the effect of phosphate binding on the transfer characteristics is interpreted in terms of its impact on the surface charge density. The electronic response of the polyamine-functionalized gFETs is shown to be sensitive to the presence of different phosphate anions, such as orthophosphate, adenosine triphosphate, and tripolyphosphate, and a simple binding model is developed to explain the dependence of the shift of the Dirac point potential on the phosphate species concentration. Afterward, the impact of phosphate-amino interactions on the immobilization of enzymes to polyamine-modified graphene surfaces is investigated, and a decrease in the amount of anchored enzyme as the phosphate concentration increases is found. Finally, multilayer polyamine-urease biosensors are fabricated while increasing the phosphate concentration in the enzyme solution, and the sensing properties of the gFETs toward urea are evaluated. It is found that the presence of simple phosphate anions alters the nanoarchitecture of the polyelectrolyte-urease assemblies, with direct implications on urea sensing.
Assuntos
Alilamina , Técnicas Biossensoriais , Grafite , Trifosfato de Adenosina , Ânions , Grafite/química , Fosfatos , Poliaminas , Polieletrólitos , Transistores Eletrônicos , Ureia , Urease/químicaRESUMO
A convenient and general protocol for the palladium-catalysed oxidation of internal allylamine derivatives to ß-amino ketones is reported. The transformation occurs at room temperature and shows a wide substrate scope as well as high functional group and N-protecting group tolerance. We also describe potential applications of the method, e.g., the synthesis of bioactive molecules or simple transformations of selected ß-amino ketones into other interesting building blocks.
Assuntos
Alilamina , Cetonas , Cetonas/química , Oxirredução , Paládio/química , CatáliseRESUMO
The topographical and chemical surface features of biomaterials are sensed by the cells, affecting their physiology at the interface. When placed on titanium, we recently discovered osteoblasts attempted caveolae-mediated phagocytosis of the sharp-edged microstructures. This active, energy-consuming process resulted in decreased osteoblastic cell functions (e.g. secretion of extracellular matrix proteins). However, chemical modification with plasma polymerized allylamine (PPAAm) was able to amplify osteoblast adhesion and spreading, resulting in better implant osseointegration in vivo In the present in vitro study, we analyzed whether this plasma polymer nanocoating is able to attenuate the microtopography-induced changes of osteoblast physiology. On PPAAm, we found cells showed a higher cell interaction with the geometrical micropillars by 30â min, and a less distinct reduction in the mRNA expression of collagen type I, osteocalcin and fibronectin after 24â h of cell growth. Interestingly, the cells were more active and sensitive on PPAAm-coated micropillars, and react with a substantial Ca2+ ion mobilization after stimulation with ATP. These results highlight that it is important for osteoblasts to establish cell surface contact for them to perform their functions.
Assuntos
Adesão Celular , Materiais Revestidos Biocompatíveis/química , Proteínas da Matriz Extracelular/metabolismo , Expressão Gênica , Osteoblastos/citologia , Alilamina/química , Linhagem Celular , Colágeno Tipo I/metabolismo , Fibronectinas/metabolismo , Humanos , Osteoblastos/metabolismo , Osteocalcina/metabolismo , Polimerização , RNA Mensageiro/análise , Propriedades de Superfície , Titânio/químicaRESUMO
BACKGROUND: Matrix-assisted laser desorption ionisation mass spectrometry imaging (MALDI-MSI) is a mass spectrometry-based technique, which can be applied for compound-specific imaging of pharmaceuticals in tissues samples. MALDI-MSI technology is widely used to visualise penetration and distribution profile through different tissues but has never been used with nail tissue. OBJECTIVES: This study used MALDI-MSI technology to visualise distribution profile and penetration into ex vivo human mycosis-infected toenails of three antifungal active ingredients amorolfine, ciclopirox and naftifine contained in topical onychomycosis nail treatment preparations, marketed as Loceryl® , Ciclopoli® and Exoderil® . METHODS: Three mycosis-infected toenails were used for each treatment condition. Six and twenty-four hours after one single topical application of antifungal drugs, excess of formulation was removed, nails were cryo-sectioned at a thickness of 20 µm, and MALDI matrix was deposited on each nail slice. Penetration and distribution profile of amorolfine, ciclopirox and naftifine in the nails were analysed by MALDI-MSI. RESULTS: All antifungal actives have been visualised in the nail by MALDI-MSI. Ciclopirox and naftifine molecules showed a highly localised distribution in the uppermost layer of the nail plate. In comparison, amorolfine diffuses through the nail plate to the deep layers already 6 hours after application and keeps diffusing towards the lowest nail layers within 24 hours. CONCLUSIONS: This study shows for the first-time distribution and penetration of certain antifungal actives into human nails using MALDI-MSI analysis. The results showed a more homogeneous distribution of amorolfine to nail and a better penetration through the infected nails than ciclopirox and naftifine.
Assuntos
Antifúngicos/farmacologia , Onicomicose/diagnóstico por imagem , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Administração Tópica , Alilamina/administração & dosagem , Alilamina/análogos & derivados , Alilamina/farmacologia , Alilamina/uso terapêutico , Antifúngicos/administração & dosagem , Antifúngicos/uso terapêutico , Ciclopirox/administração & dosagem , Ciclopirox/farmacologia , Ciclopirox/uso terapêutico , Humanos , Laca , Morfolinas/administração & dosagem , Morfolinas/farmacologia , Morfolinas/uso terapêutico , Unhas/microbiologia , Unhas/patologia , Onicomicose/tratamento farmacológicoRESUMO
Vascular adhesion protein-1 (VAP-1) is an ectoenzyme that functions as a copper-containing amine oxidase and is involved in leukocyte adhesion at sites of inflammation. Inhibition of VAP-1 oxidative deamination has become an attractive target for anti-inflammatory therapy with demonstrated efficacy in rodent models of inflammation. A previous comparison of purified recombinant VAP-1 from mouse, rat, monkey, and human gene sequences predicted that rodent VAP-1 would have higher affinity for smaller hydrophilic substrates/inhibitors because of its narrower and more hydrophilic active site channel. An optimized in vitro oxidative deamination fluorescence assay with benzylamine (BA) was used to compare inhibition of five known inhibitors in recombinant mouse, rat, and human VAP-1. Human VAP-1 was more sensitive compared to rat or mouse VAP-1 (lowest IC50 concentration) to semicarbazide but was least sensitive to hydralazine and LJP-1207. Hydralazine had a lower IC50 in rats compared to humans, although not significant. However, the IC50 of hydralazine was significantly higher in the rat compared to mouse VAP-1. The larger hydrophobic compounds from Astellas (compound 35c) and Boehringer Ingelheim (PXS-4728A) were hypothesized to have higher binding affinity for human VAP-1 compared to rodent VAP-1 since the channel in human VAP-1 is larger and more hydrophobic than that in rodent VAP-1. Although the sensitivity of these two inhibitors was the lowest in the mouse enzyme, we found no significant differences between mouse, rat, and human VAP-1. Michaelis-Menten kinetics of the small primary amines phenylethylamine and tyramine were also compared to the common marker substrate BA demonstrating that BA had the highest affinity among the substrates. Rat VAP-1 had the highest affinity for all three substrates and mouse VAP-1 had intermediate affinity for BA and phenylethylamine, but tyramine was not a substrate for mouse VAP-1 under these assay conditions. These results suggest that comparing oxidative deamination in mouse and rat VAP-1 may be important if using these species for preclinical efficacy models.
Assuntos
Amina Oxidase (contendo Cobre)/química , Benzilaminas/química , Moléculas de Adesão Celular/química , Alilamina/análogos & derivados , Alilamina/farmacologia , Animais , Benzamidas/farmacologia , Haplorrinos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Inflamação , Concentração Inibidora 50 , Insetos , Cinética , Camundongos , Oxigênio/química , Ratos , Proteínas Recombinantes/química , Especificidade da Espécie , Especificidade por SubstratoRESUMO
Naftifine is used to treat fungal skin infections as it inhibits dermatophytes, which are the cause of onychomycosis. However, naftifine's ability to permeate the human nail barrier has not been investigated, thus, the antimycotic potential is not clearly established. This work aims to evaluate the effect of penetration enhancing factors on the accumulation of naftifine hydrochloride through human nail clippings. Naftifine polymeric nail lacquers with Eudragit RL100 were developed as a suitable delivery system. Low penetration of naftifine into nail has been determined as less than 10% of applied drug dose accumulated in the nail layers. Incorporation of thioglycolic acid into formulations resulted in increased accumulation of antifungal agent in the nail layers by 100% compared with a control group. Salicylic acid did not effect naftifine accumulation in the human nail. The permeation of naftifine through the nail increased by threefold when the thioglycolic acid-containing formulation was applied and the nail was pretreated with a fractional CO2 laser. Structural changes of the nail barrier, induced by fractional CO2 laser, were visualized by microscopy. The results suggest, that naftifine nail penetration could be significantly increased when physical and chemical enhancing factors are applied.
Assuntos
Alilamina/análogos & derivados , Antifúngicos/administração & dosagem , Sistemas de Liberação de Medicamentos , Casco e Garras/efeitos dos fármacos , Unhas/efeitos dos fármacos , Onicomicose/tratamento farmacológico , Administração Tópica , Adulto , Alilamina/administração & dosagem , Alilamina/farmacocinética , Animais , Antifúngicos/farmacocinética , Bovinos , Feminino , Casco e Garras/metabolismo , Humanos , Laca , Masculino , Pessoa de Meia-Idade , Unhas/metabolismo , Onicomicose/metabolismo , Distribuição TecidualRESUMO
BACKGROUND: Studies investigating the penetration of amorolfine through the nail have shown the highest concentration in the uppermost layer and measurable antifungal activity even in the lower layers of the nail. OBJECTIVES: This pilot, ex vivo study compared the penetration of antifungal concentrations of amorolfine 5% nail lacquer in different layers of healthy, human cadaver toenails with that of terbinafine 10% nail solution, ciclopirox 8% nail lacquer and naftifine 1% nail solution. Moreover, the effect of nail filing prior to application on the penetration of amorolfine 5% was assessed. METHODS: Unfiled (n = 3) and filed (n = 3) nails were used for each antimycotic agent and amorolfine 5% nail lacquer, respectively. Twenty-four hours after topical application, the nails were sliced (10 µm), solubilised and added to agar plates seeded with Trichophyton rubrum. Zones of growth inhibition were measured. RESULTS: Only amorolfine penetrated the nails at sufficient concentrations to inhibit growth of T rubrum at different nail depths. In contrast, the comparators did not show antifungal efficacy. Nail filing resulted in larger zones of inhibition for amorolfine compared with those of intact nails. CONCLUSIONS: Unlike its comparators, a single application of amorolfine 5% nail lacquer resulted in antifungal efficacy within the nail plate. Nail filing increased the antifungal efficacy of amorolfine 5% nail lacquer.
Assuntos
Antifúngicos/administração & dosagem , Antifúngicos/farmacocinética , Laca , Morfolinas/administração & dosagem , Morfolinas/farmacocinética , Unhas/química , Administração Tópica , Alilamina/administração & dosagem , Alilamina/análogos & derivados , Alilamina/farmacocinética , Cadáver , Ciclopirox/administração & dosagem , Ciclopirox/farmacocinética , Humanos , Projetos Piloto , Terbinafina/administração & dosagem , Terbinafina/farmacocinética , Trichophyton/efeitos dos fármacos , Trichophyton/crescimento & desenvolvimentoAssuntos
Antifúngicos , Cetoconazol , Região Lombossacral , Terbinafina , Antifúngicos/uso terapêutico , Antifúngicos/administração & dosagem , Terbinafina/uso terapêutico , Terbinafina/administração & dosagem , Cetoconazol/uso terapêutico , Cetoconazol/administração & dosagem , Resultado do Tratamento , Dermatomicoses/tratamento farmacológico , Dermatomicoses/microbiologia , Administração Oral , Animais , Humanos , Cabelo/efeitos dos fármacos , Masculino , Alilamina/análogos & derivadosRESUMO
In this paper, we report on polyethylene (PE) film modified by atmospheric dielectric barrier discharge (DBD) plasma prior to the deposition of SiOx coating to improve its barrier properties. Three kinds of monomers: allylamine, acrylic acid, and ethanol, are used to modify the PE surface. For comparison, Ar and O2 plasma pre-treatments are also performed. It is found that with the addition of a monomer in the Ar DBD plasma, the grafted active groups on PE surfaces lead to dense, pinhole-free growth of the SiOx film. The oxygen transmission rate (OTR) decreases from 700 cc/m²·day·atm. for the pristine to ca. 70 cc/m²·day·atm. for the pretreatment-coated PE, which is more than a 10-fold reduction. The relationship between the grafted monomer and the great decrease of OTR is then explored via chemical composition by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and via morphology observation by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results show that the grafted functional groups of -NH2, -COOH and -OH increase the surface energy and promote the nucleation of Siâ»O radicals on polymeric surfaces, and the formation of network and cage structures in SiOx film contributes to the significant improvement of OTR.
Assuntos
Materiais Revestidos Biocompatíveis/química , Embalagem de Alimentos/métodos , Gases em Plasma/química , Polietileno/química , Dióxido de Silício/química , Acrilatos/química , Alilamina/química , Argônio/química , Difusão , Eletricidade , Etanol/química , Humanos , Membranas Artificiais , Microscopia de Força Atômica , Oxigênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
Dermatophytosis, the commonest superficial fungal infection, has gained recent attention due to its change of epidemiology and treatment failures. Despite the availability of several agents effective against dermatophytes, the incidences of chronic infection, reinfection, and treatment failures are on the rise. Trichophyton rubrum and Trichophyton interdigitale are the two species most frequently identified among clinical isolates in India. Consecutive patients (n = 195) with suspected dermatophytosis during the second half of 2014 were included in this study. Patients were categorized into relapse and new cases according to standard definitions. Antifungal susceptibility testing of the isolated Trichophyton species (n = 127) was carried out with 12 antifungal agents: fluconazole, voriconazole, itraconazole, ketoconazole, sertaconazole, clotrimazole, terbinafine, naftifine, amorolfine, ciclopirox olamine, griseofulvin, and luliconazole. The squalene epoxidase gene was evaluated for mutation (if any) in 15 T. interdigitale and 5 T. rubrum isolates exhibiting high MICs for terbinafine. A T1189C mutation was observed in four T. interdigitale and two T. rubrum isolates. This transition leads to the change of phenylalanine to leucine in the 397th position of the squalene epoxidase enzyme. In homology modeling the mutant residue was smaller than the wild type and positioned in the dominant site of squalene epoxidase during drug interaction, which may lead to a failure to block the ergosterol biosynthesis pathway by the antifungal drug.
Assuntos
Alilamina/farmacologia , Antifúngicos/farmacologia , Esqualeno Mono-Oxigenase/metabolismo , Trichophyton/efeitos dos fármacos , Trichophyton/enzimologia , Alilamina/análogos & derivados , Arthrodermataceae/efeitos dos fármacos , Ciclopirox/farmacologia , Farmacorresistência Fúngica/genética , Fluconazol/farmacologia , Itraconazol/farmacologia , Testes de Sensibilidade Microbiana , Morfolinas/farmacologia , Esqualeno Mono-Oxigenase/genética , Terbinafina/farmacologia , Trichophyton/genética , Voriconazol/farmacologiaRESUMO
The surge of antibiotic resistance in Staphylococcus aureus has created a dire need for innovative anti-infective agents that attack new targets, to overcome resistance. In S. aureus, carotenoid pigment is an important virulence factor because it shields the bacterium from host oxidant killing. Here we show that naftifine, a US Food and Drug Administration (FDA)-approved antifungal drug, blocks biosynthesis of carotenoid pigment at nanomolar concentrations. This effect is mediated by competitive inhibition of S. aureus diapophytoene desaturase (CrtN), an essential enzyme for carotenoid pigment synthesis. We found that naftifine attenuated the virulence of a variety of clinical S. aureus isolates, including methicillin-resistant S. aureus (MRSA) strains, in mouse infection models. Specifically, we determined that naftifine is a lead compound for potent CrtN inhibitors. In sum, these findings reveal that naftifine could serve as a chemical probe to manipulate CrtN activity, providing proof of concept that CrtN is a druggable target against S. aureus infections.
Assuntos
Alilamina/análogos & derivados , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Oxirredutases/antagonistas & inibidores , Staphylococcus aureus/efeitos dos fármacos , Alilamina/farmacologia , Animais , Ligação Competitiva/efeitos dos fármacos , Carotenoides/metabolismo , Desenho de Fármacos , Farmacorresistência Bacteriana , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/enzimologia , Staphylococcus aureus/patogenicidade , Fatores de Virulência , Xantofilas/antagonistas & inibidores , Xantofilas/biossínteseRESUMO
A synthesis of non-racemic ß-alkyl-ß-aryl allyl alcohols and their transformation into allylamines bearing a quaternary stereogenic center is reported. The allyl alcohols were prepared either by Cu-catalyzed enantioselective reduction of enones or by sequential alkylation/hydrostannylation/Stille coupling of non-racemic propargyl alcohols. The prepared ß-alkyl-ß-aryl allyl alcohols were converted (after carbamoylation) to the corresponding allylamine derivatives through cyanate-to-isocyanate rearrangement/nucleophilic addition with complete chirality transfer. Varying the nucleophilic agents allowed the preparation of various allylamine derivatives, including carbamates, amides, formamides, ureas, and free amines. The ozonolysis/oxidation of the resulting allylamines provided non-racemic quaternary α-amino acids.