Evaluation of two coproscopic techniques for the diagnosis of schistosomiasis in a low-transmission area in the state of Minas Gerais, Brazil

This population study, which evaluated two parasitological methods for the diagnosis of schistosomiasis mansoni, was performed in a low-transmission area in Pedra Preta, Montes Claros, Minas Gerais, Brazil. A total of 201 inhabitants of the rural area participated in this research. Four stool samples were obtained from all participants and analysed using the Kato-Katz method (18 slides) and a commercial test, the TF-Test?, which was performed quantitatively. The data were analysed to determine prevalence, the sensitivity of the diagnostic methods, the worm burden and the definition of the "gold standard", which was obtained by totalling the results of all samples examined using the Kato-Katz technique and the TF-Test?. The results showed that the prevalence obtained from the examination of one Kato-Katz slide (the methodology adopted by the Brazilian control programme) was 8% compared to 35.8% from the "gold standard", which was a 4.5-fold difference. This result indicates that the prevalence of schistosomiasis in so-called low-transmission areas is significantly underestimated.     

Yeasts from Macrobrachium amazonicum: a focus on antifungal susceptibility and virulence factors of Candida spp

In the present study, it was sought to compare yeast microbiota of wild and captive Macrobrachium amazonicum and evaluate the antifungal susceptibility and production of virulence factors by the recovered isolates of Candida spp. Additionally, cultivation water was monitored for the presence of fungi. Overall, 26 yeast isolates belonging to three genera and seven species were obtained, out of which 24 were Candida spp., with Candida famata as the most prevalent species for both wild and captive prawns. From cultivation water, 28 isolates of filamentous fungi were obtained, with Penicillium spp., Cladosporium spp. and Aspergillus spp. as the most frequent genera. Eight out of 24 Candida spp. isolates were resistant to azole derivatives, out of which four were recovered from wild-harvested prawns. As for production of virulence factors, three (12.5%) and eight (33.3%) isolates presented phospholipase and protease activity, respectively. This is the first comparative study between wild and captive prawns and the first report on yeast microbiota of M. amazonicum. The most relevant finding was the high percentage of resistant Candida spp., including from wild individuals, which suggests the occurrence of an environmental imbalance in the area where these prawns were captured.     

Parameters of Metabolic Syndrome and Its Relationship with Zincemia and Activities of Superoxide Dismutase and Glutathione Peroxidase in Obese Women

Alterations in antioxidant defense in obese people with metabolic syndrome can contribute to oxidative stress. This study assessed the relationship between the parameters of metabolic syndrome and the zincemia, activity of superoxide dismutase, and glutathione peroxidase enzymes in obese women. Seventy-three premenopausal women, aged between 20 and 50 years, were divided into two groups: case group, composed of obese (n = 37), and control group, composed of no obese (n = 36). Analyses of zinc intake, parameters of metabolic syndrome, plasma, and erythrocyte zinc, and activities of superoxide dismutase and glutathione peroxidase were carried out. The mean values of body mass index of obese women and control group were 34.5 ± 3.4 and 21.7 ± 1.9 kg/m², respectively (p < 0.05). In the study, body mass index, waist circumference, and zinc intake were higher in obese women than control group (p < 0.05). The plasma zinc and activity of superoxide dismutase did not show significant differences between obese and controls (p > 0.05). The values of erythrocyte zinc was 36.4 ± 15.0 μg/gHb and 45.4 ± 14.3 μg/gHb and of glutathione peroxidase was 46.4 ± 19.4 U/gHb and 36.7 ± 13.6 U/gHb in obese women and controls, respectively (p < 0.05). The study shows that there are alterations in biochemical parameters of zinc in obese women, with low zinc concentrations in erythrocytes. Regression analysis demonstrates that the erythrocyte zinc and activity of superoxide dismutase enzyme is influenced by components of the metabolic syndrome, and the plasmatic glucose, body mass index, and waist circumference have a negative correlation with this enzyme.     

Leukotriene B4 mediates neutrophil migration induced by heme

High concentrations of free heme found during hemolytic events or cell damage leads to inflammation, characterized by neutrophil recruitment and production of reactive oxygen species, through mechanisms not yet elucidated. In this study, we provide evidence that heme-induced neutrophilic inflammation depends on endogenous activity of the macrophage-derived lipid mediator leukotriene B(4) (LTB(4)). In vivo, heme-induced neutrophil recruitment into the peritoneal cavity of mice was attenuated by pretreatment with 5-lipoxygenase (5-LO) inhibitors and leukotriene B(4) receptor 1 (BLT1) receptor antagonists as well as in 5-LO knockout (5-LO(-/-)) mice. Heme administration in vivo increased peritoneal levels of LTB(4) prior to and during neutrophil recruitment. Evidence that LTB(4) was synthesized by resident macrophages, but not mast cells, included the following: 1) immuno-localization of heme-induced LTB(4) was compartmentalized exclusively within lipid bodies of resident macrophages; 2) an increase in the macrophage population enhanced heme-induced neutrophil migration; 3) depletion of resident mast cells did not affect heme-induced LTB(4) production or neutrophil influx; 4) increased levels of LTB(4) were found in heme-stimulated peritoneal cavities displaying increased macrophage numbers; and 5) in vitro, heme was able to activate directly macrophages to synthesize LTB(4). Our findings uncover a crucial role of LTB(4) in neutrophil migration induced by heme and suggest that beneficial therapeutic outcomes could be achieved by targeting the 5-LO pathway in the treatment of inflammation associated with hemolytic processes.     

Nematode consumption by mite communities varies in different forest microhabitats as indicated by molecular gut content analysis

Soil animals live in complex and heterogeneous habitats including litter of various types but also microhabitats such as mosses, fungal mats and grass patches. Soil food webs have been separated into a slow fungal and a fast bacterial energy channel. Bacterial-feeding nematodes are an important component of the bacterial energy channel by consuming bacteria and forming prey for higher trophic levels such as soil microarthropods. Investigating the role of nematodes as prey for higher trophic level consumers has been hampered by methodological problems related to their small body size and lack in skeletal structures which can be traced in the gut of consumers. Recent studies using molecular gut content analyses suggest that nematodes form major prey of soil microarthropods including those previously assumed to live as detritivores. Using molecular markers we traced nematode prey in fourteen abundant soil microarthropod taxa of Mesostigmata and Oribatida (both Acari) from three different microhabitats (litter, grass and moss). Consumption of nematodes varied between mite species indicating that trophic niche variation contributes to the high diversity of microarthropods in deciduous forests. Further, consumption of nematodes by Mesostigmata (but not Oribatida) differed between microhabitats indicating that trophic niches vary with habitat characteristics. Overall, the results suggest that free-living bacterial-feeding nematodes form important prey for soil microarthropods including those previously assumed to live as detritivores.     

High-pressure SANS and fluorescence unfolding study of calmodulin

Apo-calmodulin, a small soluble mainly α protein, is a calcium-dependent protein activator. Calcium binding affects the calmodulin conformation but also its stability. Calcium free form unfolds between 40 and 80 °C, whereas the calcium-saturated form is stable up to temperatures as high as 100 °C, forbidding comparison of the thermal unfolding pathways of the two forms. Thus, this paper focuses especially on the conformation of pressure-induced unfolding states of both forms of calmodulin, by combining small-angle neutron scattering (SANS) with biophysical techniques such as tyrosines and ANS fluorescence. In contrast to heat denaturation (Gibrat et al., BBA, 2012), the pressure denaturation of calmodulin is reversible up to pressures of 3000 bar (300 MPa). A pressure-induced compact intermediate state has been found for the two calmodulin forms, but their unfolding pathways are different. A domain compaction and an increase of the ANS fluorescence of holo form have been evidenced. On the contrary, a domain dilatation and an ANS fluorescence decrease have been found for the apo form. The pressure induced an increase of the interdomain distance for both calmodulin forms, suggesting that the central linker of calmodulin is flexible in solution.     

An old drug and different ways to treat cutaneous leishmaniasis: Intralesional and intramuscular meglumine antimoniate in a reference center,Rio de Janeiro,Brazil

BackgroundTreatment of cutaneous leishmaniasis (CL) remains challenging since the drugs currently used are quite toxic, thus contributing to lethality unrelated to the disease itself but to adverse events (AE). The main objective was to evaluate different treatment regimens with meglumine antimoniate (MA), in a reference center in Rio de Janeiro, Brazil.MethodologyA historical cohort of 592 patients that underwent physical and laboratory examination were enrolled between 2000 and 2017. The outcome measures of effectiveness were epithelialization and complete healing of cutaneous lesions. AE were graded using a standardized scale. Three groups were evaluated: Standard regimen (SR): intramuscular (IM) MA 10–20 mg Sb⁵⁺/kg/day during 20 days (n = 46); Alternative regimen (AR): IM MA 5 mg Sb⁵⁺/kg/day during 30 days (n = 456); Intralesional route (IL): MA infiltration in the lesion(s) through subcutaneous injections (n = 90). Statistical analysis was performed through Fisher exact and Pearson Chi-square tests, Kruskal-Wallis, Kaplan-Meier and log-rank tests.ResultsSR, AR and IL showed efficacy of 95.3%, 84.3% and 75.9%, with abandonment rate of 6.5%, 2.4% and 3.4%, respectively. IL patients had more comorbidities (58.9%; p = 0.001), were mostly over 50 years of age (55.6%), and had an evolution time longer than 2 months (65.6%; p = 0.02). Time for epithelialization and complete healing were similar in IL and IM MA groups (p = 0.9 and p = 0.5; respectively). Total AE and moderate to severe AE that frequently led to treatment interruption were more common in SR group, while AR and IL showed less toxicity.Conclusions/SignificanceAR and IL showed less toxicity and may be good options especially in CL cases with comorbidities, although SR treatment was more effective. IL treatment was an effective and safe strategy, and it may be used as first therapy option as well as a rescue scheme in patients initially treated with other drugs.     

Human Health Risk of Ingested Nanoparticles That Are Added as Multifunctional Agents to Paints: an In Vitro Study

Microorganisms growing on painted surfaces are not only an aesthetic problem, but also actively contribute to the weathering and deterioration of materials. A widely used strategy to combat microbial colonization is the addition of biocides to the paint. However, ecotoxic, non-degradable biocides with a broad protection range are now prohibited in Europe, so the paint industry is considering engineered nanoparticles (ENPs) as an alternative biocide. There is concern that ENPs in paint might be released in run-off water and subsequently consumed by animals and/or humans, potentially coming into contact with cells of the gastrointestinal tract and affecting the immune system. Therefore, in the present study we evaluated the cytotoxic effects of three ENPs (nanosilver, nanotitanium dioxide and nanosilicon dioxide) that have a realistic potential for use in paints in the near future. When exposed to nanotitanium dioxide and nanosilicon dioxide in concentrations up to 243 µg/mL for 48 h, neither the gastrointestinal cells (CaCo-2) nor immune system cells (Jurkat) were significantly affected. However, when exposed to nanosilver, several cell parameters were affected, but far less than by silver ions used as a control. No differences in cytotoxicity were observed when cells were exposed to ENP-containing paint particles, compared with the same paint particles without ENPs. Paint particles containing ENPs did not affect cell morphology, the release of reactive oxygen species or cytokines, cell activity or cell death in a different manner to the same paint particles without ENPs. The results suggest that paints doped with ENPs do not pose an additional acute health hazard for humans.