Effects of bioconversion by Battus polydamas on the chemical composition of Aristolochia spp. and evaluation of antimicrobial activity and biocompatibility

Aristolochia plants are emblematic from an ethnopharmacological viewpoint and are know to possess numerous biological properties, including antiseptic. However, the medicinal potential of these species is debatable because of their representative chemical constituents, aristolochic acids (AAs) and aristolactams (ALs), which are associated, for instance, with nephropathy and cancer. These contrasting issues have stimulated the development of approaches intended to detoxification of aristoloquiaceous biomasses, among which is included the bioconversion method using larvae of the specialist phytophagous insect Battus polydamas, previously shown to be viable for chemical diversification and to reduce toxicity. Thus, eleven Aristolochia spp. were bioconverted, and the antimicrobial activities of the plant methanolic extracts and its respective bioconversion products were evaluated. The best results were found for Aristolochia esperanzae, Aristolochia gibertii, and Aristolochia ringens against Bacillus cereus, with MIC ranging from 7.8 to 31.25 μg/mL. These three species were selected for chemical, antioxidant, cytotoxic, hemolytic, and mutagenic analyses. Chemical analysis revealed 65 compounds, 21 of them possible bioconversion products. The extracts showed potential to inhibit the formation and degradation of B. cereus biofilms. Extracts of A. gibertii and its bioconverted biomass showed antioxidant activity comparable to dibutylhydroxytoluene (BHT) standard. Bioconversion decreased the hemolytic activity of A. esperanzae and the cytotoxicities of A. esperanzae and A. gibertii. None of the extracts was found to be mutagenic. The bioactivities of the fecal extracts were maintained, and biocompatibility was improved. Therefore, the results obtained in this study reveal positive expectations about the natural detoxification process of the Aristolochia species.

Circulating myomiRNAs as biomarkers in patients with Cushing's syndrome

PURPOSE

Impairment of skeletal muscle mass and strength affects 40-70% of patients with active Cushing's syndrome (CS). Glucocorticoid excess sustains muscle atrophy and weakness, while muscle-specific microRNAs (myomiRs) level changes were associated with muscle organization and function perturbation. The aim of the current study is to explore changes in circulating myomiRs in CS patients compared to healthy controls and their involvement in IGFI/PI3K/Akt/mTOR pathway regulation in skeletal muscle.

METHODS

C2C12, mouse myocytes, were exposed to hydrocortisone (HC), and atrophy-related gene expression was investigated by RT-qPCR, WB and IF to assess HC-mediated atrophic signalling. miRNAs were evaluated in HC-treated C2C12 by PCR Arrays. MyomiRs significantly overexpressed in C2C12 were investigated in 37 CS patients and 24 healthy controls serum by RT-qPCR. The anti-anabolic role of circulating miRNAs significantly upregulated in CS patients was explored in C2C12 by investigating the IGFI/PI3K/Akt/mTOR pathway regulation.

RESULTS

HC induced higher expression of atrophy-related genes, miR-133a-3p, miR-122-5p and miR-200b-3p in C2C12 compared to untreated cells. Conversely, the anabolic IGFI/PI3K/Akt/mTOR signalling was reduced and this effect was mediated by miR-133a-3p. In CS patients miR-133a-3p and miR-200b-3p revealed higher circulating levels (p < 0.0001, respectively) compared to controls. ROC curves for miR-133a-3p (AUC 0.823, p < 0.0001) and miR-200b-3p (AUC 0.850, p < 0.0001) demonstrated that both myomiRs represent potential biomarkers to discriminate between CS and healthy subjects. Pearson's correlation analysis revealed that circulating levels of miR-133a-3p are directly correlated with 24 h urinary-free cortisol level (r = 0.468, p = 0.004) in CS patients.

CONCLUSIONS

HC induces atrophic signals by miR-133a-3p overexpression in mouse myocytes and humans. Circulating miR-133a-3p is promising biomarkers of hypercortisolism.

The medieval bronze doors of San Zeno, Verona: combining material analyses and art history

The bronze doors of the Basilica of San Zeno in Verona, Italy, are a special case in art history research. They were made by several workshops during the twelfth century: stylistically, two to three workshops were assumed to produce the metal parts of the door. However, it is still unclear when exactly and if this interpretation can be supported by the chemical composition of the metal. In this research we aimed to verify the art history interpretation by identifying the alloy composition of each individual metal plate. The composition of the supporting wooden structures are discussed. A portable ED-XRF instrument and optical microscopes were used to analyse and document the doors non-invasively. The doors were also photographed to produce high resolution orthophotos and 3D models. We can confirm that the metal parts of the doors were made of leaded tin-bronze as well as leaded brass and mounted on a wooden structure mainly made of spruce and oak wood. Chemically, two/three different groups of alloys have been identified, which can be associated with two or three different workshops, and which largely correspond to the stylistic interpretation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40494-024-01143-2.

Storage and Learning Phase Transitions in the Random-Features Hopfield Model

The Hopfield model is a paradigmatic model of neural networks that has been analyzed for many decades in the statistical physics, neuroscience, and machine learning communities. Inspired by the manifold hypothesis in machine learning, we propose and investigate a generalization of the standard setting that we name random-features Hopfield model. Here, P binary patterns of length N are generated by applying to Gaussian vectors sampled in a latent space of dimension D a random projection followed by a nonlinearity. Using the replica method from statistical physics, we derive the phase diagram of the model in the limit P,N,D→∞ with fixed ratios α=P/N and α_{D}=D/N. Besides the usual retrieval phase, where the patterns can be dynamically recovered from some initial corruption, we uncover a new phase where the features characterizing the projection can be recovered instead. We call this phenomena the learning phase transition, as the features are not explicitly given to the model but rather are inferred from the patterns in an unsupervised fashion.

Detection of 2-ethyl-1-hexanol and its modulating effect in biofilm of Fusarium oxysporum

In immunocompetent individuals, Fusarium spp. stands out as the causative agent of onychomycosis, among the non-dermatophyte molds. Despite evidence indicating that Fusarium oxysporum organizes itself in the form of a biofilm causing onychomycosis, there is little literature on the etiopathogenesis of the biofilm on the nail, specifically the signaling molecules present, known as quorum sensing (QS). Thus, this study detected the presence of a molecule related to QS from the ex vivo biofilm of F. oxysporum on human nail and investigated its effect on preformed biofilm in vitro. The detection and physicochemical characterization of a QS molecule, from the extracellular matrix (ECM), was carried out by Fourier transform infrared (FTIR) spectroscopy with an attenuated total reflectance (ATR) accessory and by headspace gas chromatography coupled to mass spectrometry (GC-MS) analyses. Determination of viable cells, cell activity, total biomass, ECM components and scanning electron microscopy (SEM) were performed to evaluate the influence of the QS molecule on the in vitro biofilm of F. oxysporum. The beginning, in the ex vivo biofilm of F. oxysporum on human nails, the volatile organic compound 2-ethyl-1-hexanol (2EH) was detected as a component of QS. Thereafter in vitro analyses, synthetic 2EH was able to modulate the biofilm by stimulating its filament, increasing total biomass and ECM production in terms of total carbohydrates, but with a reduction in total proteins and nucleic acids. We thus evidence, for the first time, the presence of 2EH in the biofilm of F. oxysporum, developed on the human nail, and the in vitro action of this compound as a QS molecule.

Antibacterial and immunological properties of piperine evidenced by preclinical studies: a systematic review

Aim: To review in vitro, in vivo, and in silico studies examining the antibacterial and immunomodulatory properties of piperine (PPN). Methods: This systematic review followed PRISMA guidelines, and five databases were searched. Results: A total of 40 articles were included in this study. Six aspects of PPN activity were identified, including antibacterial spectrum, association with antibiotics, efflux pump inhibition, biofilm effects, protein target binding, and modulation of immune functions/virulence factors. Most studies focused on Mycobacterium spp. and Staphylococcus aureus. Cell lineages and in vivo models were employed to study PPN antibacterial effects. Conclusion: We highlight PPN as a potential adjuvant in the treatment of bacterial infections. PPN possesses several antibacterial properties that need further exploration to determine the mechanisms behind its pharmacological activity.

Ascending renal infection following experimental candiduria by Candida tropicalis in immunocompromised mice

The present study evaluated renal infection resulting from the implantation of C. tropicalis in the bladder of immunosuppressed mice. Yeasts were implanted in two manners: planktonic and via preformed biofilm on a small catheter fragment (SCF). Renal histopathology and cultures was performed 72 and 144 h after cystotomy was carried out in mice from three groups: group I contained non-contaminated mice implanted with a sterile SCF; group II mice received a sterile SCF plus a yeast suspension containing 1 × 107 yeasts/mL in a planktonic form; group III mice were implanted with a SCF containing preformed C. tropicalis biofilm. Viable yeasts were found in the kidneys of mice from both groups II and III. However, after 72 h the planktonic cells (group II) invaded more quickly than the sessile cells (group III). Over a longer period (144 h), group III exhibited a more invasive infection (50% of the animals presented renal infection and the renal fungal load was 3.2 log10 CFU/g tissue) than in group II, where yeasts were not found. C. tropicalis introduced into the bladder in two ways (in planktonic or biofilm form) were able to reach the kidney and establish a renal fungal infection, causing interstitial disorders. The data of the present study therefore support the hypothesis of an ascending pathway for renal infections by C. tropicalis. Furthermore, the biofilm resulted in a greater and progressive risk of renal infection, attributed to the slow detachment of the yeasts.

Impact of invasive fungal infections in men from a state in southern Brazil: A geospatial analysis

OBJECTIVE

To analyse the records of male hospitalisation for fungal infections, including their spatial distribution and the main invasive epidemiological and sociodemographic characteristics in the State of Paraná, Brazil.

METHODS

Spatial analysis based on data from male admission records for invasive fungal infections (IFIs) in the State of Paraná, from 2015 to 2019. Data were taken from the hospital records obtained in the Hospital Information System of the Unified Health System, being collected, georeferenced and analysed to infer the existence of autocorrelation with the hospitalisation rates in the state.

RESULTS

From 2015 to 2019, there were 385 cases of IFIs in men, being more prevalent in white individuals aged 61-70 years. We observed that the metropolitan, southeast, central-eastern, north-central, northwestern and western regions formed high-high clusters, with regions with a high number of registered cases. In the regression, there was an association with socioeconomic and demographic factors that showed a correlation with the rates of hospitalisation for IFIs.

CONCLUSION

The study draws attention to Paraná as an endemic region for paracoccidioidomycosis, in addition to presenting high rates of nosocomial fungal infections. We also emphasise the importance of compulsory notification in the state and in the country to gain greater control over the incidence and prevalence of cases and to incentivise the creation of public policies for the prevention of IFIs.

Candida palmioleophila: A New Emerging Threat in Brazil?

Human activity directly or indirectly causes climate change, promoting changes in the composition of the atmosphere. This change is beyond the variation of the natural climate. In this manner, climate change could create an environmental pressure which is enough to trigger new fungal diseases. In addition to climate alterations, the onset of the COVID-19 pandemic has also been associated with the emergence of fungal pathogens. Fungi showed that an inability to grow at high temperatures limits the capacity of fungi to infect mammals. However, fungi can develop thermotolerance, gradually adapting to rising temperatures due to climate change, and generating a greater number of disease-causing organisms. In the present study, we reported the detection and identification of Candida palmioleophila isolates recovered from raw sewage samples in Niteroi city, Rio de Janeiro State, Brazil, during a monitoring program for measuring SARS-CoV-2 presence and concentration. Using polyphasic taxonomy to identify the species and evaluating some virulence aspects of this species, such as biofilm formation and extracellular enzyme production, our data highlight this species as a possible emerging pathogen in Brazil, especially in the pandemic context.

In Vitro and Ex Vivo Biofilm-Forming Ability of Rhinocladiella similis and Trichophyton rubrum Isolated from a Mixed Onychomycosis Case

Infections caused by biofilm-forming agents have important implications for world health. Mixed infections, caused by more than one etiological agent, are also an emerging problem, especially regarding the standardization of effective diagnosis and treatment methods. Cases of mixed onychomycosis (OM) have been reported; however, studies on the microbial interactions between the different fungi in biofilms formed on nails are still scarce. We describe a case of mixed OM caused by the dermatophyte Trichophyton rubrum and the black yeast-like fungus Rhinocladiella similis. Identical growths of both fungi were observed in more than 50 cultures from different nail samples. Additionally, both species were able to form organized single and mixed biofilms, reinforcing the participation of both fungi in the etiology of this OM case. R. similis seemed to grow faster during the process, suggesting that T. rubrum benefits from biofilm development when in combination. Moreover, the biofilm of the Rhinocladiella isolate exhibited exacerbated production of the extracellular matrix, which was not observed with that of a Rhinocladiella reference strain, suggesting that the isolate had natural abilities that were possibly perfected during development in the nail of the patient.

Fungal quorum-sensing molecules and antiseptics: a promising strategy for biofilm modulation?

New strategies to control fungal biofilms are essential, especially those that interfere in the biofilm organization process and cellular communication, known as quorum sensing. The effect of antiseptics and quorum-sensing molecules (QSMs) have been considered with regard to this; however, little has been elucidated, particularly because studies are often restricted to the action of antiseptics and QSMs against a few fungal genera. In this review, we discuss progress reported in the literature thus far and analyze, through in silico methods, 13 fungal QSMs with regard to their physicochemical, pharmacological, and toxicity properties, including their mutagenicity, tumorigenicity, hepatotoxicity, and nephrotoxicity. From these in silico analyses, we highlight 4-hydroxyphenylacetic acid and tryptophol as having satisfactory properties and, thus, propose that these should be investigated further as antifungal agents. We also recommend future in vitro approaches to determine the association of QSMs with commonly used antiseptics as potential antibiofilm agents.

Challenges and perspectives in research and teaching of host pathogen interaction topics: new post-pandemic times to Brazil and other South American countries

Here is our proposal to improve learning in biomedical sciences for graduate and undergraduate courses with a broad vision integrating disciplines such as molecular cell biology, biochemistry, and biophysics around concepts of pathogen interaction within vertebrate and invertebrate hosts. Our paradigm is based on the possibility offered by the pandemic to have remote activities that give access to students and researchers from different places in Brazil and Latin American countries to discuss science. A multidisciplinary view of host-pathogen interaction allows us to understand better the mechanisms involved in the pathology of diseases, as well as to formulate broad strategies for the diagnosis, treatment, and control of thereof. The approach to integrating heterogeneous groups in science involves the critical analysis of national scientific resource distribution, where only some have the possibilities to conduct competitive scientific research. Solid theoretical training, contact, collaboration with groups of excellence, and training within a multidisciplinary network are our proposals for a permanent platform of scientific strengthening and dissemination for Latin America. Here we will review the concept of host-pathogen interaction, the type of institutions where it is taught and researched, new trends in active teaching methodologies, and the current political context in science.

Case of Mixed Infection of Toenail Caused by Candida parapsilosis and Exophiala dermatitidis and In Vitro Effectiveness of Propolis Extract on Mixed Biofilm

Onychomycosis is a chronic fungal nail infection caused by several filamentous and yeast-like fungi, such as the genus Candida spp., of great clinical importance. Black yeasts, such as Exophiala dermatitidis, a closely related Candida spp. species, also act as opportunistic pathogens. Fungi infectious diseases are affected by organisms organized in biofilm in onychomycosis, making treatment even more difficult. This study aimed to evaluate the in vitro susceptibility profile to propolis extract and the ability to form a simple and mixed biofilm of two yeasts isolated from the same onychomycosis infection. The yeasts isolated from a patient with onychomycosis were identified as Candida parapsilosis sensu stricto and Exophiala dermatitidis. Both yeasts were able to form simple and mixed (in combination) biofilms. Notably, C. parapsilosis prevailed when presented in combination. The susceptibility profile of propolis extract showed action against E. dermatitidis and C. parapsilosis in planktonic form, but when the yeasts were in mixed biofilm, we only observed action against E. dermatitidis, until total eradication.

Polycaprolactone nanofibers colonized by HeLa cells: an alternative for in vitro investigation of fungal infection

Introduction: In vitro 3D equivalent tissues can be used for studies of fungal infections. Objectives: To develop 3D electrospun nanofibers using polycaprolactone (PCL) colonized by HeLa cells as a possible in vitro model for the investigation of fungal infection. Materials & methods: A PCL solution was synthesized and electrospun. HeLa cells were cultured on the nanostructured PCL scaffolds, forming a 3D structure. Physicochemical, biological and Candida albicans infection assays were performed in this model. Results: The nanostructured PCL scaffolds showed favorable physicochemical characteristics and allowed the colonization of HeLa cells, which showed indications of extracellular matrix production. Conclusions: Fungal infection was evidenced in the 3D nanostructured PCL scaffolds, being viable, economical and compatible to study fungal infections in vitro.

Performance of Two Extracts Derived from Propolis on Mature Biofilm Produced by Candida albicans

Species of the Candida genus represent the third most common cause of onychomycosis, the most frequent and difficult to treat nail infection. Onychomycosis has been attributed to fungi organized in biofilm and some natural products have proved promising for its treatment. This study aimed to evaluate the antibiofilm activity of propolis extract (PE) and its by-product (WPE) on 7-day preformed biofilms produced by Candida albicans in polystyrene microplates, as well as in an ex vivo model on human nail fragments. The cytotoxicity and permeation capacity were also assessed. Firstly, multiple parameters were evaluated over 7 days to elucidate the dynamics of biofilm formation by C. albicans. The cell viability and total biomass did not vary much from the beginning; however, days 3 and 4 were crucial in terms of metabolic activity, which was significantly increased, and the levels of extracellular matrix components, wherein proteins and nucleic acids experienced an increase, but polysaccharide levels dropped. Architecturally, one-day biofilm showed a monolayer of organized cells (blastoconidia, hyphae, and pseudohyphae), while in the seven-day biofilm there was a three-dimensional well-structured and complex biofilm. This yeast was also able to form a biofilm on both surfaces of the nail, without an additional nutritional source. Both extracts showed excellent antibiofilm activity against the 7-day preformed biofilm and were not toxic to Vero cells at concentrations compatible with the antifungal and antibiofilm activities. Both extracts permeated the experimentally infected nail, with WPE being more efficient. The results of this study, taken together, reinforce the potential of these natural products, containing propolis, as a safe option for the topical treatment of onychomycosis.

Hospital Trichosporon asahii isolates with simple architecture biofilms and high resistance to antifungals routinely used in clinical practice

Infections by Trichosporon spp. are increasing worldwide and its treatment remains a challenge. Colonization of medical devices has been considered as a predisposing factor for trichosporonosis, which is related to fungal biofilm production. Thus, this study aimed to evaluate the ability of six hospital T. asahii isolates to form biofilm on abiotic surface, as well as to investigate the impact of three classic antifungals on both planktonic and biofilm forms. The fungal identification was based on macro and micromorphological characteristics, biochemical tests and confirmation by mass spectrometry assisted by the flight time desorption/ionization matrix (MALDI-TOF MS). Antifungal susceptibility assay of planktonic cells showed inhibitory and fungicidal concentrations ranging from 2.5 to 10 µg/mL for voriconazole, 2 to 8 µg/mL for fluconazole, and 1 to 4 µg/mL for amphotericin B. All T. asahii strains were able to form biofilms on the polystyrene microplates surface within 24 h, showing a simple architecture when compared with Candida spp. biofilm. On the other hand, the same antifungals did not show action in neither the inhibition of biofilm formation nor on the formed biofilm. Concluding, the present study reinforced the relevance of the MALDI-TOF MS methodology for a safe identification of T. asahii. Classic antifungals were active on the planktonic form, but not on the biofilms. All isolates formed biofilms on the polystyrene microplates and showed a simple architecture.

Mixed Fungal Biofilms: From Mycobiota to Devices, a New Challenge on Clinical Practice

Most current protocols for the diagnosis of fungal infections are based on culture-dependent methods that allow the evaluation of fungal morphology and the identification of the etiologic agent of mycosis. Most current protocols for the diagnosis of fungal infections are based on culture-dependent methods that enable the examination of the fungi for further identification of the etiological agent of the mycosis. The isolation of fungi from pure cultures is typically recommended, as when more than one species is identified, the second agent is considered a contaminant. Fungi mostly survive in highly organized communities that provoke changes in phenotypic profile, increase resistance to antifungals and environmental stresses, and facilitate evasion from the immune system. Mixed fungal biofilms (MFB) harbor more than one fungal species, wherein exchange can occur that potentialize the effects of these virulence factors. However, little is known about MFB and their role in infectious processes, particularly in terms of how each species may synergistically contribute to the pathogenesis. Here, we review fungi present in MFB that are commensals of the human body, forming the mycobiota, and how their participation in MFB affects the maintenance of homeostasis. In addition, we discuss how MFB are formed on both biotic and abiotic surfaces, thus being a significant reservoir of microorganisms that have already been associated in infectious processes of high morbidity and mortality.

Plants of the Phytolaccaceae family with antimicrobial activity: A systematic review

Phytolaccaceae is a plant family of the order Caryophyllales, which includes species used in traditional medicine to treat diseases. The purpose of this study was to investigate Phytolaccaceae family plants with potential antimicrobial action, through a systematic review. The study was conducted following the criteria of PRISMA protocol. The search was performed in the electronic databases PubMed, Web of Science, Scopus, and LILACS, in March 2021. The search strategy used free descriptors and terms, limiting articles to the English language, regardless of publication year. The risk of bias and the quality of publications were based on the CONSORT checklist, modified for in vitro studies and SYRCLE's RoB tool for in vivo study. Five independent judges performed quality assessments of publications and risk of bias analysis. Ninety-five publications were retrieved from the databases and, after screening and eligibility criteria, 22 articles remained, from 1998 to 2019. In the selected studies, the plants were obtained from eight countries. In vivo and in vitro studies of extracts from the Phytolaccaceae family plants, evaluating antibacterial (8 publications), antifungal (8), anti-Trypanosoma (2), anti-Leishmania (2), antiviral (1), and antiamoebic (1) activities, are included. The plant species identified belong to genera Petiveria, Phytolacca, Gallesia, Trichostigma, and Seguieria. The risk of bias in the 22 publications both in vitro and in vitro was suboptimal. The evidence obtained showed that the Phytolaccaceae family, a source of plants with antimicrobial action, can serve as a basis for the creation of new herbal medicines, expanding the possibility of treatment for infectious diseases and stimulating their preservation and biodiversity. However, more high-quality studies are needed to establish the clinical efficacy of the plant.

Promising effect of propolis and a by-product on planktonic cells and biofilm formation by the main agents of human fungal infections

Few antifungals available today are effective in treating biofilms. Thus, it is urgent to discover new compounds, such as natural products, that provide improvements to existing treatments or the development of new antifungal therapies. This study aimed to perform a comparative analysis between the green propolis extract (PE) and its by-product, a waste of propolis extract (WPE) through a screening with Candida sp., Fusarium sp. and Trichophyton sp. The antifungal property of PE and WPE was assessed by the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determination in planktonic cells. The influence of both extracts on the inhibition of biofilm formation in these fungi was also tested. The WPE MIC and MFC values (68.75 to 275.0 µg/mL) were three to twelve times lower than the values obtained for PE (214.06 to 1712.5 µg/mL). PE was more efficient than WPE in inhibiting the biofilm initial phase, especially in C. albicans. Meanwhile, WPE had dose-dependent behavior for the three fungi, being more effective on filamentous ones. Both PE and WPE showed excellent antifungal activity on planktonic cells and demonstrated great efficacy for inhibiting biofilm formation in the three fungi evaluated.

Relevant insights into onychomycosis' pathogenesis related to the effectiveness topical treatment

Onychomycosis (OM) is a fungal infection, responsible for about 50% of nail diseases. OM has been attributed to the ability of fungi to naturally organize themselves into biofilms on nail surfaces. However, little is known about the exact role of the biofilm in the etiopathogenesis of OM, as well as its influence in the permeation of a topical treatment. The objectives of this study were to review the literature for topical OM treatments in clinical trials, assess the efficiency of these treatments, and discuss factors that could affect the success of these treatments. First, a systematic search of articles published in the MEDLINE database (PubMed) between January 2010 and December 2019 was conducted, focusing on drugs under clinical trials for the topical treatment of OM. Of the publications selected, it was clear that none of them had considered the fungi organized in biofilm. Therefore, we reflected on some important variables involved in OM, such as the nail structure and the mechanism of fungal invasion. Some methods, such as histopathologic analysis and spectroscopy techniques, were found to be effective in the detection of nail biofilm, and could be used in future drug permeation studies. This review allowed us to conclude that novel antifungals for the topical treatment of OM must consider the drug to permeate through biofilm. Natural products, such as propolis, seem strong candidates in this respect.

Excitonic absorption and defect-related emission in three-dimensional MoS2 pyramids

MoS2 micro-pyramids have demonstrated interesting properties in the fields of photonics and non-linear optics. In this work, we show the excitonic absorption and cathodoluminescence (CL) emission of MoS2 micro-pyramids grown by chemical vapor deposition (CVD) on SiO2 substrates. The excitonic absorption was obtained at room and cryogenic temperatures by taking advantage of the cathodoluminescence emission of the SiO2 substrate. We detected the CL emission related to defect intra-gap states, localized at the pyramid edges and with an enhanced intensity at the pyramid basal vertices. The photoluminescence and absorption analysis provided the Stokes shift of both the A and B excitons in the MoS2 pyramids. This analysis provides new insights into the optical functionality of MoS2 pyramids. This method can be applied to other 3D structures within the 2D materials family.

Native state of natural proteins optimizes local entropy

The differing ability of polypeptide conformations to act as the native state of proteins has long been rationalized in terms of differing kinetic accessibility or thermodynamic stability. Building on the successful applications of physical concepts and sampling algorithms recently introduced in the study of disordered systems, in particular artificial neural networks, we quantitatively explore how well a quantity known as the local entropy describes the native state of model proteins. In lattice models and all-atom representations of proteins, we are able to efficiently sample high local entropy states and to provide a proof of concept of enhanced stability and folding rate. Our methods are based on simple and general statistical-mechanics arguments, and thus we expect that they are of very general use.

General and genetic toxicology studies of Aleurites moluccana (L.) Willd. seeds in vitro and in vivo assays

ETHNOPHARMACOLOGY RELEVANCE

Aleurites moluccana is popularly used for the diseases like ulcers, fever, headache, asthma, conjunctivitis, gonorrhea, inflammation, hepatitis, and rheumatism. The seed, also known as "noz da Índia", has been popularly consumed for weight loss purposes but reports of toxicity have been associated with its ingestion. In the literature, there are not enough studies to elucidate its toxicology, so evaluating the general and genetic toxicological of A. moluccana seeds can provide data to ensure their intake.

AIM OF THE STUDY

The objective of the present study was to elucidate the oral toxicity, mutagenicity, genotoxicity and cytotoxicity of A. moluccana seeds in vitro and in vivo assays.

MATERIALS AND METHODS

The chemical composition of the aqueous extract of A. moluccana seeds (AEAMS) was analyzed in relation to phenolic compounds, tannins, flavonoids and fatty acid. For the in vitro assays, the cytotoxic potential was assessed by the MTS assay whereas the mutagenic potential was assessed by the Ames test. For in vivo assays, was conducted an acute oral toxicity study, with "Up-and-Down Procedure" and repeated dose toxicity with "Repeated Dose 28-Day Oral Toxicity". To assess genetic damage, mutagenic potential was assessed by the micronucleus test whereas the polychromatic erythrocyte/normochromatic erythrocyte ratio was obtained with bone marrow cells to determine the cytotoxic potential and genotoxic potential was assessed by the comet assay using peripheral blood cells.

RESULTS

AEAMS did not show cytotoxic and mutagenic potential in vitro. No clinical signs of toxicity were observed in animals after the acute oral toxicity test, suggesting that the LD₅₀ of aqueous extract of A. moluccana seeds > 2000 mg/kg in a single dose by intragastric route. However, in toxicity at repeated doses for 28 days, the doses initially established (250; 500 and 750 mg/kg/day by intragastric route) caused mortality in the animals and the reestablished doses (25, 50 and 100 mg/kg/day by intragastric route) showed no changes in parameters or clinical signs attributed to toxicity. Furthermore, AEAMS also did not show mutagenic, genotoxic and cytotoxic potential in vivo.

CONCLUSIONS

AEAMS did not show cytotoxic, genotoxic and mutagenic potential in vitro and in vivo. And although the AEAMS has an LD₅₀ > 2000 mg/kg, and does not have physiological, biochemical, hematological, histopathological changes or clinical signs related to toxicity when administered in low concentrations and for a short period, in high concentrations and continued use caused toxicity and mortality in Wistar rats. In order to obtain complementary results, is recommended highly that further mid and long-term toxicological studies are investigated, and in no-rodent specie.

Insight into the antifungals used to address human infection due to Trichosporon spp.: a scoping review

Trichosporonosis infections have been increasing worldwide. Providing adequate treatment for these infections remains a challenge. This scoping review contains information about potential antifungals to treat this pathology. Using online databases, we found 76 articles published between 2010 and 2020 related to this topic. Classic antifungals, molecules and biomolecules, repositioned drugs and natural products have been tested against species of Trichosporon. Experimental research has lacked depth or was limited to in vitro and in vivo tests, so there are no promising new candidates for the clinical treatment of patients with trichosporonosis. Furthermore, most studies did not present appropriate scientific criteria for drug tests, compromising their quality.

First Study of Naturally Formed Fungal Biofilms on the Surface of Intragastric Balloons

BACKGROUND

Intragastric balloon (IGB) is a medical device used in the endoscopic treatment of pre-obesity and obesity. The involvement of IGB with biofilms has been previously reported; however, little is still known. We determine the frequency of biofilms naturally formed on the external surface of IGB, as well as some variables related to IGB types and patients features, species of fungi involved, and biofilm evidence.

METHODS

A retrospective study was conducted based on endoscopies and medical records of patients with explanted IGB between 2015 and 2018, which had masses strongly adhered to the surface of the balloon, suspecting the presence of a biofilm. From 2018, the samples of those masses were investigated seeking biofilm characterization based on mycological and structural aspects.

RESULTS

A total of 149 endoscopies were surveyed; 27 IGBs (18.12%) showed signs suggesting biofilm formation. There was no significant difference between biofilm involvement in IGB and the anthropometric and demographic profile of the patients. On the other hand, there was a significant difference regarding the IGB type, 24.05% of the adjustable IGB were compromised by biofilm, while in non-adjustable IGB, it was 11.43% (p = 0.04; OR 2.45; 95% CI, 0.98-6.12). Candida glabrata was the most isolated fungal species from the well-organized fungal biofilm.

CONCLUSIONS

The frequency of fungal biofilm naturally formed on the external surface of IGB was elevated. The risk of biofilm formation was increased for the adjustable IGB, but it did not relate to the demographic data and anthropometric patient profile.

Characterization of a biofilm formed by Fusarium oxysporum on the human nails

BACKGROUND

Fusarium spp. has been considered as an onychomycosis agent, but little is known about the etiopathogenesis of fusarial onychomycosis; thus, the objective of this study was to characterize the fungal-nail interaction and the consequences of the nail infection process by Fusarium oxysporum using the human nail, in an ex␣vivo model.

METHODS

The kinetic of biofilm production and infection by F. oxysporum using the nail as the only nutritional source were evaluated by scanning electron microscopy, number of culturable cells, metabolic activity, characterization of extracellular matrix, spectroscopy and histopathology analyses.

RESULTS

After evaluating the biofilm kinetic over 7 days using different parameters and techniques, it was possible to characterize the Fusarium-nail interaction.

CONCLUSIONS

This study is a part of a big project aiming to clarify the fusarial pathogenesis and contributes to proving F. oxysporum is able to adapt, grow, develop, and form a biofilm on healthy human nails, which are crucial steps for the invasion process.

Different expression levels of ALS and SAP genes contribute to recurrent vulvovaginal candidiasis by Candida albicans

Aim: To study the behavior of Candida albicans in women with vulvovaginal candidiasis (VVC), recurrent VVC (RVVC) and asymptomatic (AS), regarding adhesion on HeLa cells and their ability to express secreted aspartic proteinases (SAP) genes, agglutinin-like sequence (ALS) genes and HWP1. Materials & methods: The adhesion of Candida albicans to HeLa cells was evaluated by colony-forming units, and the expressed genes were evaluated by qRT-PCR. Results: AS and VVC isolates showed greater ability to adhere HeLa cells when compared with RVVC isolate. Nevertheless, RVVC isolate exhibited upregulation of a large number of genes of ALS and SAP gene families and HWP1 gene. Conclusion: The results demonstrated that RVVC isolate expressed significantly important genes for invasion and yeast-host interactions.

Cytotoxicity, mutagenicity and acute oral toxicity of aqueous Ocotea minarum leaf extracts

Ocotea minarum (Nees & Mart.) Mez., a native species of Brazil, is used in the treatment of infections and oxidative stress; however, there is no scientific evidence of its toxicological characteristics. We assessed the cytotoxicity, mutagenic activity, and acute oral toxicity of the aqueous extract isolated from O. minarum leaves. The cytotoxicity of this extract was evaluated in tumour and non-tumour cell lines, while the Ames test with a Salmonella Typhimurium was used to determine the mutagenic activity. Wistar rats received a single 2 g/kg dose as part of an LD₅₀ toxicity assessment. Our results showed that the aqueous extract of O. minarum leaves did not present cytotoxic and mutagenic properties and was not toxic, with an LD₅₀ greater than 2 g/kg. Therefore, the O. minarum extracts are pharmacologically safe and can continue to be investigated for the development of new drugs and herbal medicines.

Synthesis, structural characterization, and prospects for new cobalt (II) complexes with thiocarbamoyl-pyrazoline ligands as promising antifungal agents

Candida spp. cause invasive fungal infections. One species, Candida glabrata, may present intrinsic resistance to conventional antifungal agents, thereby increasing mortality rates in hospitalized patients. In this context, metal complexes present an alternative for the development of new antifungal drugs owing to their biological and pharmacological activities demonstrated in studies in the last decades. Accordingly, in this study we have synthesized and characterized two new Co(II) complexes with thiocarbamoyl-pyrazoline ligands to assess their antimicrobial, mutagenic, and cytotoxic potential. For antimicrobial activity, the broth microdilution method was performed against ATCC strains of Candida spp. and fluconazole dose-dependent isolates of C. glabrata obtained from urine samples. The Ames test was used to assess mutagenic potential. The reduction method of the MTS reagent (3 [4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium) was performed with HeLa, SiHa, and Vero cells to determine cytotoxicity. Both complexes exhibited fungistatic and fungicidal activity for the yeasts used in the study, demonstrating greater potential for C. glabrata ATCC 2001 and the C. glabrata CG66 isolate with a Minimum Inhibitory Concentration MIC from 3.90 to 7.81 μg mL^-1 and fungicidal action from 7.81 to 15.62 μg mL^-1. The complexes inhibited and degraded biofilms by up to 90% and did not present mutagenic and cytotoxic potential at the concentrations evaluated for MIC. Thus, the complexes examined herein suggest promising alternatives for the development of new antifungal drugs.

Effect of Silicon dioxide coating of acrylic resin surfaces on Candida albicans adhesion

Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.

Propolis extract has bioactivity on the wall and cell membrane of Candida albicans

ETHNOPHARMACOLOGICAL RELEVANCE

The use of natural products such as propolis extract (PE) is a promising alternative when topically administered to replace conventional antifungals, mostly due to its therapeutic applications, ease of access and low toxicity. However, despite being the subject of several mycology studies, they focus primarily on exploiting their antimicrobial activity, lacking information on the mechanisms of action of PE on Candida spp., characterizing its antifungal potential.

AIM OF THE STUDY

To elucidate the bioactivity of PE on the cellular structure of Candida albicans.

MATERIALS AND METHODS

A total of seven C. albicans clinical isolates plus a reference strain of C. albicans ATCC 90028 were used in this study. The PE was characterized and its effect on C. albicans was determined by susceptibility and growth kinetics assays; interference on C. albicans germination and filamentation; evaluation of the integrity of the C. albicans cell wall and membrane, as well as its mutagenic potential.

RESULTS

The PE presented strong inhibitory activity, which showed its greatest antifungal activity at 12 h with dose and time dependent fungistatic characteristics, effectively inhibiting and interfering on C. albicans filamentation. In addition, PE caused membrane and cell wall damage with intracellular content extravasation. Moreover, PE was not mutagenic.

CONCLUSIONS

The bioactivity of PE is mainly related to the loss of integrity membrane as well as the integrity of the cell wall and consequent increase in permeability, without mutagenic effects.

Microbiological and virulence aspects of Rhodotorula mucilaginosa

We aimed to characterize microbiologically clinical isolates of R. mucilaginosa isolated from colonization of a patient with chronic renal disease (CKD), as well as to evaluate their phylogeny, antifungal susceptibility, virulence, and pathogenicity in order to infer the potential to become a possible infective agent. For this study, two isolates of R. mucilaginosa from oral colonization of a CKD patient were isolated, identified and characterized by classical (genotypic and phenotypic) methods. Susceptibility to conventional antifungals was evaluated, followed by biofilm production, measured by different techniques (total biomass, metabolic activity, colony forming units and extracellular matrix quantification). Finally, the pathogenicity of yeast was evaluated by infection of Tenebrio molitor larvae. All isolates were resistant to azole and sensitive to polyenes and they were able to adhere and form biofilm on the abiotic surface of polystyrene. In general, similar profiles among isolates were observed over the observed periods (2, 24, 48 and 72 hours). Regarding extracellular matrix components of biofilms at different maturation ages, R. mucilaginosa was able to produce eDNA, eRNA, proteins, and polysaccharides that varied according to time and the strain. The death curve in vivo model showed a large reduction in the survival percentage of the larvae was observed in the first 24 hours, with only 40 % survival at the end of the evaluation. We infer that colonization of chronic renal patients by R. mucilaginosa offers a high risk of serious infection. And also emphasize that the correct identification of yeast is the main means for an efficient treatment.

Silver nanoparticles stabilized with propolis show reduced toxicity and potential activity against fungal infections

Aim: Elucidate the antifungal efficacy of biologically synthesized silver nanoparticles with ethanolic propolis extract (AgNPs PE) against the planktonic forms and biofilms of clinically important fungi. Materials & methods: AgNPs were synthesized, characterized and evaluated for cytotoxicity, mutagenicity and antimicrobial activity. Results: AgNPs PE displayed a colloidal appearance, good stability and size of 2.0–40.0 nm. AgNPs PE demonstrated lower cytotoxicity and nonmutagenic potential. In addition, AgNPs PE displayed antifungal properties against all tested isolates, inhibiting growth at concentrations lower than the cytotoxic effect. Mature biofilms treated for 48 h with AgNPs PE showed significant reduction of viable cells, metabolic activity and total biomass. Conclusion: This is the first time that AgNPs have been synthesized from an ethanolic extract of propolis only, proving antifungal, antibiofilm, atoxic and nonmutagenic properties.

The treatment with pasireotide in Cushing's disease: effect of long-term treatment on clinical picture and metabolic profile and management of adverse events in the experience of a single center

PURPOSES

Pasireotide is the first medical therapy officially approved for adult patients with Cushing's disease (CD) experiencing failure of pituitary surgery or not candidates for surgery. The current study aimed at investigating pasireotide effects on clinical picture and metabolic profile in patients enrolled in the phase III CSOM230B2305 trial at Naples center. In addition, the current study focused on safety issues encountered during the study, detailing the management of the different adverse events associated with the treatment with pasireotide in Naples center.

METHODS

Fourteen patients entered the study; eight patients, receiving pasireotide for at least 6 months, were considered for the efficacy analysis, whereas the entire cohort of 14 patients was considered for the safety analysis.

RESULTS

Full or partial disease control was obtained in 85.7% of patients, according to a "per-protocol" methodology analysis, and in 42.9% of patients, according to an "intention-to-treat" methodology analysis, after 12 months of treatment. A relevant improvement in clinical signs and symptoms, mainly in facial rubor, supraclavicular fat pad, bruising, hirsutism, and muscle strength was observed; body weight, body mass index, and waist circumference significantly reduced, and a slight non-significant reduction was observed in the prevalence of visceral obesity, hypercholesterolemia, and hypertriglyceridemia. Deterioration of glucose metabolism represented the most common adverse event, occurring in 71.4% of patients, and requiring a dietary regimen as first step, metformin therapy and/or long-acting insulin as second step, and short-acting insulin, as third step; no patients discontinued treatment for hyperglycaemia. Additional adverse events of interest were nausea (21.4%), and vomiting (14.3%), spontaneously resolved in few weeks or some months, except in one patient unsuccessfully treated with metoclopramide and ondansetron, and diarrhoea (14.3%), improved with loperamide treatment. Millimetric gallstones and biliary sludge (7.1%) were managed with ursodeoxycholic acid, inducing lithiasis and biliary sludge resolution, whereas hypocortisolism-related adverse events (7.1%) were resolved with a reduction in the pasireotide dose.

CONCLUSIONS

The current study on a limited series of patients contributes to confirm that pasireotide may be considered a valid option for treatment of patients with CD, although it requires an appropriate management of adverse events, especially hyperglycaemia.

Antiproliferative activity and energy calculations of a new triterpene isolated from the palm tree Acrocomia totai

Acrocomia totai Mart (Arecaceae) is a palm tree native to South America, widely studied for biodiesel production. The aim of this work was to perform the first phytochemical study of A. totai leaves, as well as to do biological assays against human cancer cell lines. A new triterpene of the hopane class named totaiol (1), three known triterpenes (2-4), and two phytosteroids (5-6) were identified. The new natural product was characterized using 1 D and 2 D NMR, single crystal X-ray diffraction analises, and high resolution mass spectrometry. The intercontacts in the crystal packing were also analised. Complete stereochemical characterization of compound 1 revealed an unusual positioning pattern for methyl and isopropenyl groups in the polycyclic skeleton. Compounds 1-5 were evaluated for the first time in antiproliferative assays against Ca Ski, MCF-7 and MCF-10 cells. The new natural product was active against Ca Ski cells with IC₅₀ ≤ 6.25 µg mL^-1.

The ability of farnesol to prevent adhesion and disrupt Fusarium keratoplasticum biofilm

A biofilm is represented by a community of microorganisms capable of adhering to a surface and producing substances that envelop the cells, forming an extracellular matrix. The extracellular matrix is responsible for protecting microorganisms against environmental stress, hosts the immune system and confers resistance to antimicrobials. Fusarium keratoplasticum is a common species of FSSC (Fusarium solani species complex) associated with human infections, being the most prevalent species related to biofilm formation in hospital water systems and internal pipelines. With this in mind, this study aimed to characterise the biofilm formed by the fungus F. keratoplasticum and to evaluate the effects of farnesol, a fungal quorum sensing (QS) molecule, on the preformed biofilm and also during its formation at different times (adhesion and 24, 48 and 72 h). F. keratoplasticum is able to adhere to an abiotic surface and form a dense biofilm in 72 h, with increased total biomass and matrix modulation with the presence of extracellular DNA, RNA, polysaccharides and proteins. Farnesol exhibited important anti-biofilm activity, causing the destruction of hyphae and the extracellular matrix in preformed biofilm and preventing the adhesion of conidia, filamentation and the formation of biofilm. Few studies have characterised the formation of biofilm by filamentous fungi. Our findings suggest that farnesol acts efficiently on F. keratoplasticum biofilm since this molecule is capable of breaking the extracellular matrix, thereby disarranging the biofilm.

Implications of the presence of yeasts in tracheobronchial secretions of critically ill intubated patients

The presence of some microorganisms in the respiratory tract is a known risk factor for the infection of air passages; however, it is not clear whether this holds true for Candida spp. Thus, our objective was to determine the frequency of yeast colonization in the tracheobronchial secretions of critically ill intubated patients and to assess the presence of these yeasts in the infra-cuff region of the endotracheal tube (ET). Patients aged 18 years or older who had been using an endotracheal tube for 48 hours were recruited. Tracheal secretions were collected; after extubation, the ETs were cut into two fragments in the infra-cuff region. One of these fragments was placed in a solution containing antibiotics and sent to the lab for culture and identification of yeasts. The remaining fragment was fixed and subjected to scanning electron microscopy (SEM). In total, 20 patients with an average age of 73.3 years (± 13.1) participated in this study. These patients remained under endotracheal intubation and invasive mechanical ventilation for an average of 6.4 (± 1.8) and 13.5 days (± 15), respectively. Of these patients, 45 % showed respiratory tract colonization by yeasts of the Candida genus, with C. albicans being the most frequently isolated species (66.7 %). Moreover, in almost 90 % of these patients, blastoconidia of the same yeast were found in the infra-cuff portion of the ET, as evidenced by SEM, strongly fixed on the ET surface. Yeasts isolated from both the infra-cuff region and the tracheobronchial secretions were susceptible to amphotericin B and fluconazole. In conclusion, our results show that the frequency of colonization by yeasts of the Candida genus in the tracheobronchial secretions of intubated patients within 48 hours is high, and that these species can also be found as a biofilm on the ET surface.

Occurrence of dermatophytoses in patients from the Sistema Único de Saúde

BACKGROUND

Dermatophytosis is a cutaneous disease caused by filamentous keratinophilic fungi belonging to the genera Trichophyton, Microsporum and Epidermophyton, which present a high prevalence in the general population, being among the most common mycoses affecting about 20% of the world's population.

OBJECTIVE

To carry out the epidemiological survey of cases of dermatophytosis in patients from the Sistema Único de Saúde in a regional Laboratory in the period of 5 years (2009 to 2013).

METHODS

A retrospective study (January 2009 to December 2013) was carried out with a qualitative and quantitative design, through the registry book of the laboratory, Mycology Sector, where cases of patients with suspected dermatomycosis were analyzed.

RESULTS

In a 5-year period, a total of 4467 cases were suspected of having a fungal infection. Of these, 68.74% (3071) cases were of dermatomycosis. In relation to cultures with fungal growth, 12.54% (385 cases) were dermatophyte fungi and 7.97% (245 cases) non-dermatophyte fungi were isolated. Among the species identified, there was a higher prevalence of T. rubrum complex (75%), T. mentagrophytes complex (11.68%) and M. canis (7.01%). Regarding the sites analyzed, nail involvement was the most frequent in 75% of the cases.

STUDY LIMITATIONS

This work is representative in the studied region.

CONCLUSIONS

Dermatomycosis samples are the most frequent among all samples of fungal infections from these patients, with the nail being the most affected area and the fungi T. rubrum complex and T. mentagrophytes complex the most frequent.

FATAL cryptococcal meningitis in a child with hyper-immunoglobulin M syndrome, with an emphasis on the agent

Following a fatal case of Cryptococcus neoformans meningitis in a child with X-linked hyper-immunoglobulin M syndrome (XHIGM), we evaluated the fungal isolate in an experimental infection in a mouse model with respect to microbiology, epidemiology, virulence and response to therapy. The minimum inhibitory concentrations for antifungals in the susceptibility test were 0.5mg/L for amphotericin B, 4.0mg/L for fluconazole and 0.12mg/L for voriconazole. Evaluation of pathogenicity by means of an experimental infection in BALB/c mice showed that fungus isolated from the blood and cerebrospinal fluid of the child was able to disseminate, reaching the spleen, lungs and brain, where it caused significant macroscopic alterations in the size and texture of each organ. Treatment of infected mice with amphotericin B reduced the fungal load in the spleen and lungs, but not in the brain.

Multi-electrode sequential versus single electrode stimulation to elicit the stapedial reflex during cochlear implantation: Correlation with maximum comfort level

OBJECTIVES

To assess whether electrical stimulation sequentially delivered through 4 electrodes located in different cochlear areas may elicit the stapedial reflex at lower levels compared to single electrode stimulation and to correlate the sequentially obtained values with the maximum comfort level (C-level).

PATIENTS AND METHODS

A retrospective study was performed on 35 post-verbal adult patients (age 19-80 years) consecutively implanted in 2 cochlear implant centers, evaluating the level of stimulation (pulse width) necessary to electrically evoke the stapedial reflex with two different stimulation modalities: single electrode versus sequential 4 electrode stimulation. Threshold values were compared with C-level obtained at activation.

RESULTS

The average differences of pulse width and C-level were significantly smaller (P<0.0001) when the stapedial reflex was obtained with the sequential stimulation modality and reached statistical significance for every single electrode (P<0.0001).

CONCLUSIONS

Stapedial reflex thresholds obtained with sequential stimulation through 4 different electrodes significantly correlate to the C-level obtained at the first setting and may be helpful in defining the upper limit of the dynamic field during initial CI mapping.

Effects of intratracheal Fusarium solani inoculation in immunocompetent mice

Fusariosis is an infection that is caused by fungi of the Fusarium genus. It is the second most common fungus that is associated with human fungal infections, usually in immunocompromised individuals. The incidence of such infections has been increasing, including in immunocompetent hosts. Studies of host-pathogen interactions are scarce, and the pathophysiology of the disease is unknown. One limitation of such studies is the lack of adequate techniques for mammalian infection, in which no standardized protocols have been established with fungi with a focus on the respiratory tract. The aim of the present study was to assess the first 24 h of infection after the intratracheal inoculation of F. solani microconidia in immunocompetent mice. Colony-forming units (CFU) were counted, and histopathological analysis was performed. Under conditions of high fungal burden, F. solani caused lethal tissue damage in the lungs. Under conditions of low fungal burden, the infection was not lethal, but several alterations of pulmonary tissue and the presence of the fungus in the lungs were observed. No evidence of fungal dissemination was found in the kidneys, spleen, liver, or heart 24 h after infection. The present intratracheal model effectively established fungal infection and appears to be suitable for studies of Fusarium spp.

Neurophysiological changes after cognitive-motor tasks in Parkinson's disease patients with deep brain stimulation

Chronic deep brain stimulation (CDBS) is a surgical treatment that reduces the cardinal signs of Parkinson's disease (PD). Although CDBS has been in use for a long time, very little has been reported on its supposed effects on cognition, particularly in relation to implants in the subthalamic nucleus. The results of the rare studies that do exist are controversial, and in many cases the studies have several design flaws. The present study compared cortical activation during three tasks (action execution, action observation and motor imagery) in PD patients with and without subthalamic implants. The study sample consisted of 36 volunteers, divided into three groups: healthy controls, PD patients with CDBS of the subthalamic nucleus, and PD patients without CDBS. Through a quantitative electroencephalogram assessment, absolute beta power was examined to observe the interaction between group and cognitive motor tasks. The electrodes at sites Fp1, Fp2, F7, F8, F3, Fz and F4, located in the prefrontal and frontal regions, were analyzed and a Group x Task interaction (p < 0.05) was observed for all of them. These findings suggest that CDBS of the subthalamic nucleus is efficient in reducing some of the effects of PD in these study tasks. At the same time, the dysfunctions found in several cortical areas, characteristic of PD, limited the effects of the CDBS. The results of this study suggest that CDBS of the subthalamic nucleus can modulate cognitive-motor aspects of PD.

Nanopartículas de prata biossintetizadas por Mikania glomerata Sprengel inibem o crescimento de Candida albicans e Staphylococcus aureus

Introdução: Nos últimos anos ocorreu o aumento de casos relacionados com a infecção por Candida spp. e Staphylococcus spp., bem como o aparecimento de cepas resistentes a antibióticos convencionais. A biossíntese de nanopartículas consiste na redução de um íon metálico por compostos de origem natural como metabólitos secundários de plantas e organismos, sendo a forma mais indicada por apresentar menor toxicidade quando comparada à síntese química. Desta forma, a síntese biológica constitui uma alternativa para a obtenção de novos agentes ativos para o tratamento de infecções microbianas. Objetivos: Sintetizar nanopartículas de prata a partir do extrato aquoso de Mikania glomerata Sprengel e avaliar possível atividade microbicida e citotóxica. Material e Métodos: Para a síntese das nanopartículas de prata (AgNPs) foi utilizado um extrato aquoso das folhas de M. glomerata e uma solução de nitrato de prata. As AgNPs sintetizadas foram avaliadas por espectrofotômetro UV-vis e espectrometria de absorção atômica com chama. Além disso, a atividade antimicrobiana foi avaliada contra cepas de Candida albicans e Staphylococcus aureus e atividade citotóxica contra linhagens celulares HeLa e Vero. Resultados: As AgNPs são mais eficientes no combate à linhagem de Candida albicans e Staphylococcus aureus quando comparadas ao extrato puro administrado. Até a concentração de 100 mg/mL do extrato puro não foi observado efeito inibitório em ambos os micro-organismos. Entretanto quando em contato com as AgNPs, a concentração inibitória foi de 0,006 mg/mL e 0,1 mg/mL para S. aureus e C. albicans, respectivamente. O efeito citotóxico nas células se comportou de maneira dose-dependente, apresentando maior potencial citotóxico contra a linhagem celular cancerosa HeLa. Conclusão: As AgNPs sintetizadas apresentaram potencial antimicrobiano contra C. albicans e S. aureus, além de baixa atividade contra células normais, indicando sua confiabilidade para aplicação das AgNPs como forma alternativa de tratamento. Estes resultados são promissores e contribuem para pesquisa relacionada à produção de medicamentos utilizando extrato de plantas e metais.

Fusarium oxysporum is an onychomycosis etiopathogenic agent

AIM

To evaluate and characterize the etiopathogenesis of the fusarial onychomycosis in an ex vivo study through fragments of sterile human nail, without the addition of any nutritional source.

MATERIALS & METHODS

The infection and invasion of Fusarium oxysporum in the nail were evaluated by scanning electron microscopy (SEM), CFU, matrix, histopathology and Fourier Transform Infrared Spectrometer coupled to an equipment with diamond accessory (FTIR-ATR).

RESULTS

F. oxysporum infected and invaded across the nail, regardless of application face. However, the dorsal nail surface was the strongest barrier, while the ventral was more vulnerable to infection and invasion process. The fungal-nail interaction resulted in the formation of a dense biofilm.

CONCLUSION

F. oxysporum infect and invade the healthy human nail, resulting in biofilm formation. Therefore, F. oxysporum is likely a primary onychomycosis agent.

Propolis Extract for Onychomycosis Topical Treatment: From Bench to Clinic

Onychomycosis is a chronic fungal infection of nails, commonly caused by dermatophyte fungi, primarily species of Trichophyton. Because of the limited drug arsenal available to treat general fungal infections and the frequent failure of onychomycosis treatment, the search for new therapeutic sources is essential, and topical treatment with natural products for onychomycosis has been encouraged. Propolis, an adhesive resinous compound produced by honeybees (Apis mellifera), has shown multiple biological properties including significant antifungal and anti-biofilm activities in vitro. In spite of promising in vitro results, in vivo results have not been reported so far. This study assessed an ethanol propolis extract (PE) as a topical therapeutic option for onychomycosis, including its characterization in vitro and its applicability as a treatment for onychomycosis (from bench to clinic). The in vitro evaluation included analysis of the cytotoxicity and the antifungal activity against the planktonic cells and biofilm formed by Trichophyton spp. We also evaluated the capacity of PE to penetrate human nails. Patients with onychomycosis received topical PE treatments, with a 6-month follow-up period. The results of the in vitro assays showed that PE was non-toxic to the cell lines tested, and efficient against both the planktonic cells and the biofilm formed by Trichophyton spp. The results also showed that PE is able to penetrate the human nail. The results for PE applied topically to treat onychomycosis were promising, with complete mycological and clinical cure of onychomycosis in 56.25% of the patients. PE is an inexpensive commercially available option, easy to obtain and monitor. Our results indicated that PE is a promising natural compound for onychomycosis treatment, due to its ability to penetrate the nail without cytotoxicity, and its good antifungal performance against species such as Trichophyton spp. that are resistant to conventional antifungals, both in vitro and in patients.

Candida parapsilosis isolates from burn wounds can penetrate an acellular dermal matrix

We isolated and identified yeasts from burn wounds and evaluated the ability of Candida parapsilosis isolates from burn wounds to penetrate an acellular dermal matrix (ADM). A prospective study was conducted with patients from the burn treatment center of North Paraná University Hospital in Londrina, Brazil from February 2015 to January 2016. Yeast cultures were obtained from the tissue of burn wounds that had been debrided and cleansed with 2% chlorhexidine. After identification and confirmation of the purity of the culture, the yeasts were placed on ADM fragments and incubated for three or seven days. During the study period, 273 patients were treated, and 36 of these patients fulfilled the inclusion criteria and provided samples for culture. Yeasts were isolated in 19.44% (n = 7) of the cultures, and the following species were identified: C. parapsilosis (57.1%), C. albicans (28.6%), and C. glabrata (14.3%). C. parapsilosis, the most frequent species, was chosen for the ADM tests. We demonstrated active penetration of the ADM by the yeast isolates from burn wounds. C. parapsilosis grew on ADM and penetrated the matrix, indicating that this yeast, which is common in skin and cutaneous wounds, has the potential to colonize and pass through ADM, a medical device that is frequently used to dress and regenerate burn wounds.

Murine model for the evaluation of candiduria caused by Candida tropicalis from biofilm

To evaluate the pathophysiology of catheter-associated candiduria, the bladders of female mice were infected with Candida tropicalis. One group was implanted with a catheter fragment with preformed biofilm by cystotomy technique, while another group received, in separate, a sterile catheter fragment and a correspondent yeast suspension. The bladder tissues were examined by histopathology and the quantity of colony forming units was evaluated. All the animals presented inflammation and the presence of C. tropicalis was observed in the tissue within 72 h of the introduction of biofilm, while 75% of the mice remained infected after 144 h. However, only 50% of animals from the group infected with C. tropicalis in suspension (planktonic yeasts), exhibited such signs of infection over time. The cystotomy technique is therefore viable in mice, and is an effective model for evaluating the pathogenesis of candiduria from catheter biofilms. The model revealed the potential of C. tropicalis infectivity and demonstrated more effective evasion of the host response in biofilm form than the planktonic yeast.