Development of an ionic liquid-based dispersive liquid-liquid microextraction method for the determination of nifurtimox and benznidazole in human plasma

Dispersive ionic liquid-liquid microextraction combined with liquid chromatography and UV detection was used for the determination of two antichagasic drugs in human plasma: nifurtimox and benznidazole. The effects of experimental parameters on extraction efficiency - the type and volume of ionic liquid and disperser solvent, pH, nature and concentration of salt, and the time for centrifugation and extraction - were investigated and optimized. Matrix effects were detected and thus the standard addition method was used for quantification. This microextraction procedure yielded significant improvements over those previously reported in the literature and has several advantages, including high inter-day reproducibility (relative standard deviation=1.02% and 3.66% for nifurtimox and benznidazole, respectively), extremely low detection limits (15.7 ng mL-1 and 26.5 ng mL-1 for nifurtimox and benznidazole, respectively), and minimal amounts of sample and extraction solvent required. Recoveries were high (98.0% and 79.8% for nifurtimox and benznidazole, respectively). The proposed methodology offers the advantage of highly satisfactory performance in addition to being inexpensive, simple, and fast in the extraction and preconcentration of these antichagasic drugs from human-plasma samples, with these characteristics being consistent with the practicability requirements in current clinical research or within the context of therapeutic monitoring. © 2013 Elsevier B.V

Intra-instar larval cannibalism in Anopheles gambiae (s.s.) and Anopheles stephensi (Diptera: Culicidae)

BACKGROUND: Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1) has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4) of Anopheles gambiae (s.s.) and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size) on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. RESULTS: Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s.) than in An. stephensi. In both species the total number of cannibalistic events increased from 0-24 to 0-48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. CONCLUSIONS: The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s.) and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior and lower cannibalism rate. The understanding of cannibalistic behavior and the factors affecting it is of utmost importance for malaria vectors, as nutrition during larval development can strongly affect the fitness of adult female mosquitoes and ultimately their vector ability

Using network analysis to identify seasonal patterns and key nodes for risk-based surveillance of pig diseases in Italy

The description of the pattern of livestock movements between herds provides essential information for both improving risk-based surveillance and to understand the likely spread of infectious diseases. This study provides a description of the temporal pattern of pig movements recorded in Italy on a 4-year period (2013–2016). Data, provided by the National Livestock registry, were described by social network analysis and the application of a walk-trap algorithm for community detection. Our results show a highly populated community located in Northern Italy, which is the focal point of the Italian industrial pig production and as a general pattern an overall decline of medium and backyard farms and an increase in the number of large farms, in agreement with the trend observed by other EU pig-producing countries. A seasonal pattern of all the parameters evaluated, including the number of active nodes in both the intensive and smaller production systems, emerged: that is characterized by a higher number of movements in spring and autumn, linked with the breeding and production cycle as pigs moved from the growing to the finishing phase and with periods of increased slaughtering at Christmas and Easter. The same pattern was found when restricting the analysis to imported pig batches. Outbreaks occurring during these periods would have a greater impact on the spread of infectious diseases; therefore, targeted surveillance may be appropriate. Finally, potential super-spreader nodes have been identified and represent 0.47% of the total number of pig holdings (n = 477). Those nodes are present during the whole study period with a similar ranking in their potential of being super-spreaders. Most of them were in Northern Italy, but super-spreaders with high mean out-degree centrality were also located in other Regions. Seasonality, communities and super-spreaders should be considered when planning surveillance activity and when applying disease control strategies

Population pharmacokinetic study of benznidazole in pediatric chagas disease suggests efficacy despite lower plasma concentrations than in adults

Introduction: Chagas disease, caused by the parasite Trypanosoma cruzi, can lead to long term cardiac morbidity. Treatment of children with benznidazole is effective, but no pediatric pharmacokinetics data are available and clinical pharmacology information on the drug is scarce. Patients and Methods: Prospective population pharmacokinetic (PK) cohort study in children 2-12 years old with Chagas disease treated with oral benznidazole 5-8 mg/kg/day BID for 60 days. (clinicaltrials.gov #NCT00699387). Results: Forty children were enrolled in the study. Mean age was 7.3 years. A total of 117 samples were obtained from 38 patients for PK analysis. A one compartment model best fit the data. Weight-corrected clearance rate (CL/F) showed a good correlation with age, with younger patients having a significantly higher CL/F than older children and adults. Simulated median steady-state benznidazole concentrations, based on model parameters, were lower for children in our study than for adults and lowest for children under 7 years of age. Treatment was efficacious in the 37 patients who completed the treatment course, and well tolerated, with few, and mild, adverse drug reactions (ADRs). Discussion: Observed benznidazole plasma concentrations in children were markedly lower than those previously reported in adults (treated with comparable mg/kg doses), possibly due to a higher CL/F in smaller children. These lower blood concentrations were nevertheless associated to a high therapeutic response in our cohort. Unlike adults, children have few adverse reactions to the drug, suggesting that there may be a direct correlation between drug concentrations and incidence of ADRs. Our results suggest that studies with lower doses in adults may be warranted. Trial Registration: ClinicalTrails.gov NCT00699387.Facultad de Ciencias Exacta

Índice comprimento/largura da folha no melhoramento do feijão (Phaseolus vulgaris L.).

O índice comprimento/largura do folíolo central da folha composta originada no quarto nó da planta é um dos descritores referidos à proteção de cultivares de feijão (a determinação na folha do quarto nó é estabelecida por analogia com a determinação da cor do referido folíolo contida no formulário ?Descritores mínimos de feijão?, do Serviço Nacional de Proteção de Cultivares- SNPC)