<i>Trypanosoma rangeli:</i> growth in mammalian cells <i>in vitro</i> and action of a repositioned drug (17-AAG) and a natural extract (<i>Artemisia sp</i>. essential oil)

Trypanosoma rangeli and T. cruzi are both parasitic unicellular species that infect humans. Unlike T. cruzi, the causative agent of Chagas disease, T. rangeli is an infective and non-pathogenic parasite for humans, but pathogenic for vectors from the Rhodnius genus. Because both species can coexist in different hosts and overlap their infective cycles but very little is known about the infection of T. rangeli in mammalian cells, we decided to characterize both the development of this parasite in cell culture and the effect of therapeutic agents with potential trypanocidal action on it. We found that T. rangeli exhibits a cycle of infection in Vero cells similar to that for T. cruzi and that the repurposed drug, 17-AAG, and the natural extract Artemisia sp. essential oil produce a toxic effect on epimastigotes showing a trypanocidal action from the fifth day of culture. Both treatments also affected the infection of trypomastigotes and reduced the capacity of replication of amastigotes of T. rangeli. Since T. cruzi / T. rangeli coinfection cases have been reported, the finding of drugs with potential activity against both species could be significant in the future. Furthermore, studies of susceptibility of both species to drugs could also help to know the different mechanisms of pathogenicity in humans displayed by T. cruzi that are absent in T. rangeli     

Application of full-factorial design for optimization of the moisture determination in wheat flour using infrared scales

We studied the parameters that may affect the analysis of the moisture content in wheat flour using infrared scales. The parameters were studied by one-factor at a time methodology and then, by full-factorial design (2³). The best condition using infrared scales occurred at 120 °C, with a sample weight of 1.5 g and an exposure time to infrared radiation of 6 min. We observed the interaction effect between the three factors studied. The analysis time was 60 times lower than classical method. The optimized method for determination of the moisture content in wheat flour using infrared scales was validated to range between 9 and 17 %.     

Optical properties of hybrid T3Pyr/SiO2/3C-SiC nanowires

A new class of nanostructured hybrid materials is developed by direct grafting of a model thiophene-based organic dye on the surface of 3C-SiC/SiO₂ core/shell nanowires. TEM-EDX analysis reveals that the carbon distribution is more spread than it would be, considering only the SiC core size, suggesting a main contribution from C of the oligothiophene framework. Further, the sulfur signal found along the treated wires is not detected in the as-grown samples. In addition, the fluorescent spectra are similar for the functionalized nanostructures and T3Pyr in solution, confirming homogeneous molecule grafting on the nanowire surface. Chemical and luminescence characterizations confirm a homogeneous functionalization of the nanowires. In particular, the fluorophore retains its optical properties after functionalization.     

Assessment of intradialysis calcium mass balance by a single pool variable‐volume calcium kinetic model

Introduction: A reliable method of intradialysis calcium mass balance quantification is far from been established. We herein investigated the use of a single‐pool variable‐volume Calcium kinetic model to assess calcium mass balance in chronic and stable dialysis patients. Methods: Thirty‐four patients on thrice‐weekly HD were studied during 240 dialysis sessions. All patients were dialyzed with a nominal total calcium concentration of 1.50 mmol/L. The main assumption of the model is that the calcium distribution volume is equal to the extracellular volume during dialysis. This hypothesis is assumed valid if measured and predicted end dialysis plasma water ionized calcium concentrations are equal. A difference between predicted and measured end‐dialysis ionized plasma water calcium concentration is a deviation on our main hypothesis, meaning that a substantial amount of calcium is exchanged between the extracellular volume and a nonmodeled compartment. Findings: The difference between predicted and measured values was 0.02 mmol/L (range ?0.08:0.16 mmol/L). With a mean ionized dialysate calcium concentration of 1.25 mmol/L, calcium mass balance was on average negative (mean ± SD ?0.84 ± 1.33 mmol, range ?5.42:2.75). Predialysis ionized plasma water concentration and total ultrafiltrate were the most important predictors of calcium mass balance. A significant mobilization of calcium from the extracellular pool to a nonmodeled pool was calculated in a group of patients. Discussion: The proposed single pool variable‐volume Calcium kinetic model is adequate for prediction and quantification of intradialysis calcium mass balance, it can evaluate the eventual calcium transfer outside the extracellular pool in clinical practice.     

Short communication: Repeatability of intravenous glucose tolerance test traits in young Holstein-Friesian cattle

Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices.