Publications by authors named "Patrick V Quelemes"

Objective: This work aimed to evaluate the in vitro effect of zinc oxide-eugenol paste (ZOE) on planktonic aggregates (EfPA) and biofilm (EfBio) of Enterococcus faecalis, focusing on their morphological aspects observed and analyzed using atomic force microscopy (AFM).

Design: The eugenol and paste were characterized by Gas Chromatography coupled with Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The effect of ZOE on EfPA and EfBio was evaluated by a direct-contact test through colony counting and crystal violet staining protocol.

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Postbiotic is the term used to define the soluble factors, metabolic products, or byproducts released by live probiotic bacteria or after its lysis. The objective of this study was to carry out the chemical characterization of the postbiotic of LR-32 and to evaluate its in vitro effect on the development of the biofilm. After the cultivation of the probiotic strain, the postbiotic was extracted by centrifuging the culture and filtering the supernatant.

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Hydrogels are structures that have value for application in the area of tissue engineering because they mimic the extracellular matrix. Naturally obtained polysaccharides, such as chitosan (CH) and cashew gum, are materials with the ability to form polymeric networks due to their physicochemical properties. This research aimed to develop a scaffold based on chitosan and phthalated cashew tree gum and test it as a support for the growth of human mesenchymal stem cells.

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Streptococcal bacteremia that occurs during invasive dental procedures can lead to infective endocarditis (IE) in children with certain heart diseases. Prior to such procedures, antibiotic prophylaxis (AP) with amoxicillin (AMPC) is recommended. However, the detection of amoxicillin-resistant strains (AMPC-RS) in the mouths of children with heart diseases raises the concern that they would be uncovered by the action of standard AP.

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The dental intracanal disinfection is crucial to achieve the success of endodontic treatment, avoiding the maintenance of endodontic infections. Chlorhexidine digluconate can act as an irrigating agent for it. However, it can cause tissue irritation in high concentrations.

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The gutta-percha cones used in endodontic treatment are produced in aseptic conditions and their composition includes zinc oxide, which is responsible for antibacterial activity. However, there is the possibility of microbial contamination by manipulation, aerosol or during storage. Although several chemical agents have been tested for their decontamination, there is no consensus on the best disinfection protocol to be used.

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This study presents a green synthesis route to silver nanoparticles (AgNPs) stabilized with cashew gum (CG) or carboxymethylated cashew gum (CCG) using microwave-assisted synthesis and evaluates their antibacterial activity. The antimicrobial activity was measured by determining the minimum inhibitory concentration (MIC) with Staphylococcus aureus and Escherichia coli. In both cases of the presence of CG and CCG, it was found that higher pH lead to more efficient conversion of silver nitrate to AgNPs with well dispersed, spherical and stable particles as well as low crystallinity.

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Modified polysaccharides have been featured as new agents against bacterial infection presenting biocompatibility in their use for medical purposes. In this work, we carried out the quaternization of Angico gum (AG). Quaternized Angico gum derivatives (QAG) were produced using a cationic moiety (3-Chloro-2-hydroxypropyl)trimethylammonium chloride onto the gum backbone.

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This work describes a solvent-free method for the chemical modification of cashew gum (Anacardium occidentale L.) using phthalic anhydride in different proportions with different reaction times. Four biopolymers were synthesized and characterized by FTIR, NMR, and elemental analysis.

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Silver nanoparticles have been shown to possess considerable antibacterial activity, but in vivo applications have been limited due to the inherent, but low, toxicity of silver. On the other hand, silver nanoparticles could provide cutaneous protection against infection, due to their ability to liberate silver ions via a slow release mechanism, and their broad-spectrum antimicrobial action. Thus, in this work, we describe the development of a carboxymethyl cellulose-based hydrogel containing silver nanoparticles.

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Pilocarpus microphyllus Stapf ex Wardlew (Rutaceae), popularly known as jaborandi, is a plant native to the northern and northeastern macroregions of Brazil. Several alkaloids from this species have been isolated. There are few reports of antibacterial and anthelmintic activities for these compounds.

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Patagonia's biodiversity has been explored from many points of view, however, skin secretions of native amphibians have not been evaluated for antimicrobial peptide research until now. In this sense, Pleurodema thaul is the first amphibian specie to be studied from this large region of South America. Analysis of cDNA-encoding peptide in skin samples allowed identification of four new antimicrobial peptides.

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Chemical modifications to cashew gum (CG) structure have been previously reported to obtain new physicochemical characteristics, however until now there were no reports of modifications by introduction of new functional groups to add cationic character. This study presents a quaternization route for CG using a quaternary ammonium reagent. The chemical features of the quaternized cashew gum derivatives (QCG) were analyzed by: FTIR, elemental analysis, degree of substitution, Zeta potential, H NMR and H-C correlation (HSQC).

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Ethnopharmacological Relevance: There are ethnopharmacological reports supporting the use of neem (Azadirachta indica A. Juss) leaf against bacterial and worm infections. However there is a lack of studies about its effect on bacterial biofilm formation and Schistosoma mansoni worms.

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Article Synopsis
  • * The peptides varied in structure, with some being amidated and others having free carboxylates, showing similarities to other peptides from the same frog genus.
  • * Antimicrobial tests revealed that all peptides, except one, were effective against at least one strain of Gram-negative bacteria, with the most potent peptide, ocellatin-PT8, inhibiting multiple harmful bacteria without affecting human cells at tested concentrations.
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Background: The methicillin resistance of bacteria from the genus Staphylococcus and its ability to form biofilms are important factors in pathogenesis of these microorganisms. Thus, the search for new antimicrobials agents, especially from plants, has been intensified. In this context, Terminalia species have been the subject of research for many pharmacological activities.

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Background: Type I collagen is an abundant natural polymer with several applications in medicine as matrix to regenerate tissues. Silver nanoparticles is an important nanotechnology material with many utilities in some areas such as medicine, biology and chemistry. The present study focused on the synthesis of silver nanoparticles (AgNPs) stabilized with type I collagen (AgNPcol) to build a nanomaterial with biological utility.

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Composites prepared from polyaniline (PANI) and the ceramic technology of titanium dioxide (TiO2) have been proposed, however, the interaction of these materials with greater control of molecular arrangement becomes attractive in order to achieve properties not previously described or yet the optimization of those already reported. Therefore, in this study, thin hybrid films made of polyaniline (PANI), a conductive polymer, and the technological ceramic, titanium dioxide (TiO2), were prepared by the layer-by-layer (LbL) self-assembly technique. The films were characterized by cyclic voltammetry (CV), UV-VIS spectroscopy and atomic force microscopy (AFM).

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Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities.

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The present study describes the development of a green synthesis of silver nanoparticles reduced and stabilized by exuded gum from Anacardium occidentale L. and evaluates in vitro their antibacterial and cytotoxic activities. Characterization of cashew gum-based silver nanoparticles (AgNPs) was carried out based on UV-Vis spectroscopy, transmission electron microscopy and dynamic light scattering analysis which revealed that the synthesized silver nanoparticles were spherical in shape, measuring about 4 nm in size with a uniform dispersal.

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