Meeting nutritional adequacy in the Brazilian population increases pesticide intake without exceeding chronic safe levels.

Achieving nutritional adequacy requires an increase in fresh foods consumption, which may increase pesticide intakes. This study aimed to identify required dietary modifications to achieve nutritional adequacy without exceeding the acceptable daily intake (ADI) for pesticides. Data from the National Dietary Survey 2017-2018 were linked to the pesticide database from the Program on Pesticide Residue Analysis in Food. We performed linear programming models to design nutritionally adequate diets constrained by food preferences for different constraints on pesticide intake at the least cost increment. Nutritional adequacy led to an increase in pesticide intakes without exceeding their ADI. Modifications in diets varied according to the model, but, in general, consisted in an increase in fruits and vegetables, dairy, and seafood, and a reduction in rice, red meat, and sugar-sweetened beverages quantities. In conclusion, meeting nutritional adequacy increases pesticide intake compared to the observed diets, without representing a health concern to consumers.

Pre-miRNA-149 G-quadruplex as a molecular agent to capture nucleolin.

One of the most significant challenges in capturing and detecting biomarkers is the choice of an appropriate biomolecular receptor. Recently, RNA G-quadruplexes emerged as plausible receptors due to their ability to recognize with high-affinity proteins. Herein, we have unveiled and characterized the capability of the precursor microRNA 149 to form a G-quadruplex structure and determined the role that some ligands may have in its folding and binding capacity to nucleolin. The G-quadruplex formation was induced by K+ ions and stabilized by ligands, as demonstrated by nuclear magnetic resonance and circular dichroism experiments. Surface plasmon resonance measurements showed a binding affinity of precursor microRNA 149 towards ligands in the micromolar range (10-5-10-6 M) and a strong binding affinity to nucleolin RNA-binding domains 1 and 2 (8.38 × 10-10 M). Even in the presence of the ligand PhenDC3, the binding remains almost identical and in the same order of magnitude (4.46 × 10-10 M). The molecular interactions of the RNA G-quadruplex motif found in precursor miRNA 149 (5'-GGGAGGGAGGGACGGG- 3') and nucleolin RNA-binding domains 1 and 2 were explored by means of molecular docking and molecular dynamics studies. The results showed that RNA G-quadruplex binds to a cavity between domains 1 and 2 of the protein. Then, complex formation was also evaluated through polyacrylamide gel electrophoresis. The results suggest that precursor microRNA 149/ligands and precursor microRNA 149/nucleolin RNA-binding domains 1 and 2 form stable molecular complexes. The in vitro co-localization of precursor microRNA 149 and nucleolin in PC3 cells was demonstrated using confocal microscopy. Finally, a rapid and straightforward microfluidic strategy was employed to check the ability of precursor microRNA 149 to capture nucleolin RNA-binding domains 1 and 2. The results revealed that precursor microRNA 149 can capture nucleolin RNA-binding domains 1 and 2 labeled with Fluorescein 5-isothiocyanate in a concentration-dependent manner, but PhenDC3 complexation seems to decrease the ability of precursor microRNA 149 to capture the protein. Overall, our results proved the formation of the G-quadruplex structure in the precursor microRNA 149 and the ability to recognize and detect nucleolin. This proof-of-concept study could open up a new framework for developing new strategies to design improved molecular receptors for capture and detection of nucleolin in complex biological samples.

Aptamer-based approaches to detect nucleolin in prostate cancer.

We have investigated the expression of nucleolin (NCL) in liquid biopsies of prostate cancer (PCa) patients and healthy controls to determine its correlation with tumor prognosis. To detect NCL we used a modified AS1411 aptamer designated by AS1411-N5. In presence of NCL, AS1411-N5 increases the fluorescence by assuming a G-quadruplex (G4) structure, while in the absence of NCL the fluorescence signal remains quenched. The structural characterization of AS1411-N5 was performed by biophysical studies, which demonstrated the formation of G4 parallel conformation in the presence of 100 mM K+ and the ability to recognize NCL with high affinity (KD = 138.1 ±â€¯5.5 nM). Furthermore, the clinical relevance of NCL in PCa liquid biopsies was assessed by using an NCL-based ELISA assay. The protein was measured in the peripheral blood mononuclear cells (PBMCs) cell lysate of 158 individuals, including PCa patients and healthy individuals. The results depicted a remarkable increase of NCL levels in the PBMC's lysate of PCa patients (mean of 626.1 pg/mL whole blood) when compared to healthy individuals (mean of 198.5 pg/mL whole blood). The ELISA results also provided evidence for the usefulness of determining NCL levels in advanced PCa stages. Furthermore, a microfluidic assay showed the ability of AS1411-N5 in recognizing NCL in spiked human plasma samples.

Probabilistic dietary risk assessment of triazole and dithiocarbamate fungicides for the Brazilian population.

Residue data for triazoles (TR) and dithiocarbamates (DT) in 30,786 samples of 30 foods were obtained from mainly two national monitoring programs, and consumption data from a national survey conducted among persons aged 10 years or older. About 16% of the samples contained TR, mainly grape (53.5%), and 16.2% contained DT, mainly apple (59.3%). Flusilazole was the index compound used for the acute effects of TR for women of child-bearing-age (cranium-facial malformation and skeletal variation), cyproconazole for the chronic effects of TR (hepatoxicity), and ethylene-bis-dithitiocarbamates (EBDC) for DT (thyroid toxicity). Exposures were estimated using the Monte Carlo Risk Assessment software. Different models were tested, and a Model-Then-Add approach was found to best estimate the chronic exposures to DT and TR. At the 99.9th percentile (P99.9), the cumulative acute TR intakes accounted for up to 0.5% of the flusilazole ARfD, mainly from beans and rice consumption. The chronic TR and DT intakes accounted for 1 and 6.7% of the respective index compound ADIs, with beans and rice accounting for most of the TR intake (∼70%), and apple for about 51-56% of the DT intake. The estimated risks from the exposure to TR and DT indicate no health concern for the Brazilian population.

Dietary cumulative acute risk assessment of organophosphorus, carbamates and pyrethroids insecticides for the Brazilian population.

Cumulative acute dietary risk assessments of organophosphorus (OPs), carbamates (CBs) and pyrethroids (PYs) were conducted for the Brazilian population. Residue data for 30786 samples of 30 foods were obtained from two national monitoring programs and one University laboratory, and consumption data from a national survey conducted among persons 10 years or older. Acephate and methamidophos were used as index compounds (IC) for OPs, oxamyl for CBs and deltamethrin for PYs. Exposures were estimated using the Monte Carlo Risk Assessment (MCRA 8.2) software. Orange and orange juice (mainly containing methidathion), pasta and salted bread (mainly pirimiphos-methyl) contributed most to the OPs intake. Rice accounted for 80% of the CBs intake (teenagers), mainly due to aldicarb. Pasta, salted bread and beans contributed most to the PYs intake (9-14%), mainly due to bifenthrin. The intake did not exceed the ARfD at the 99.9th percentile for OPs, CBs and PYs, and the risks from the exposure were not considered of health concern. When food consumption data become available for children under age 10, studies in the cumulative exposure should be conducted, as this age group is the most critical among the population, mainly due to their higher food consumption per kg body weight.

Pesticide residues in cashew apple, guava, kaki and peach: GC-µECD, GC-FPD and LC-MS/MS multiresidue method validation, analysis and cumulative acute risk assessment.

A multiresidue method for the determination of 46 pesticides in fruits was validated. Samples were extracted with acidified ethyl acetate, MgSO4 and CH3COONa and cleaned up by dispersive SPE with PSA. The compounds were analysed by GC-FPD, GC-µECD or LC-MS/MS, with LOQs from 1 to 8 µg/kg. The method was used to analyse 238 kaki, cashew apple, guava, and peach fruit and pulp samples, which were also analysed for dithiocarbamates (DTCs) using a spectrophotometric method. Over 70% of the samples were positive, with DTC present in 46.5%, λ-cyhalothrin in 37.1%, and omethoate in 21.8% of the positive samples. GC-MS/MS confirmed the identities of the compounds detected by GC. None of the pesticides found in kaki, cashew apple and guava was authorised for these crops in Brazil. The risk assessment has shown that the cumulative acute intake of organophosphorus or pyrethroid compounds from the consumption of these fruits is unlikely to pose a health risk to consumers.

Exposure to toxic chemicals in the diet: is the Brazilian population at risk?

In Brazil, in the last 20 years, dietary risk assessments have been conducted on pesticides, mycotoxins, food additives, heavy metals (mainly mercury), environmental contaminants (mainly DDT) and acrylamide, a compound formed during food processing. The objectives of this paper were to review these studies, discuss their limitations and uncertainties and identify the most critical chemicals that may pose a health risk to Brazilian consumers. The studies have shown that the cumulative intake of organophosphorus and carbamate pesticides by high consumers of fruits and vegetables may represent a health concern (up to 169% of the ARfD), although the benefits of consuming large portions of those foods most probably overcome the risks. High consumers of maize products may also be at risk due to the presence of fumonisin (355% of the PMTDI), a mycotoxin present at high levels in Brazilian maize. The studies conducted in the Brazilian Amazon have shown that riparian fish consumers are exposed to unsafe levels of mercury. However, this is a more complex issue, as mercury levels in the region are naturally high and the health benefits of a fish-based diet are well known. Studies conducted both in Brazil and internationally on acrylamide have shown that the exposure to this genotoxic compound, mainly from the consumption of French fries and potato chips, is of health concern. Reducing the population dietary exposure to toxic chemicals is a challenge for government authorities and food producers in all countries. Management strategies aimed at decreasing exposure to the critical chemicals identified in this review involve limiting the use or eliminating highly toxic pesticides, implementing good agricultural practices to decrease maize contamination by fumonisins, educating local fish-eating communities toward a fish diet less contaminated by mercury, and changing dietary habits concerning the consumption of fried potatoes, the main processed food containing acrylamide.

Variability of organophosphorus insecticide residues in large size crops grown in commercial farms in Brazil.

Field trials were conducted in commercial agricultural areas in Brazil to determine the variability of residues of parathion methyl, diazinon and methidathion in individual units of large crops treated twice with a mixture of the three pesticides. Over 120 random samples were collected, extracted with ethyl acetate and residues determined by GC/FPD. The recoveries and their coefficient of variation were, in general, within the acceptable levels during sample analyses. Residues in papaya and mango were not affected by the position of the fruits in the plant, apparently more or less exposed to the pesticides. Variability factor ?, defined as the 97.5th percentile divided by the mean of residues in all samples taken from a field ranged from 2.0-2.6. The variability of residues within the plant contributed to about 34-61% of the field variability. The results found in this study support the variability factor of 3 adopted by the FAO/WHO for the deterministic estimation of dietary acute intake of pesticides.