Pharmacokinetic/pharmacodynamic modeling of cortical dopamine concentrations after quetiapine lipid core nanocapsules administration to schizophrenia phenotyped rats.

Schizophrenia (SCZ) response to pharmacological treatment is highly variable. Quetiapine (QTP) administered as QTP lipid core nanocapsules (QLNC) has been shown to modulate drug delivery to the brain of SCZ phenotyped rats (SPR). In the present study, we describe the brain concentration-effect relationship after administrations of QTP as a solution or QLNC to SPR and naïve animals. A semimechanistic pharmacokinetic (PK) model describing free QTP concentrations in the brain was linked to a pharmacodynamic (PD) model to correlate the drug kinetics to changes in dopamine (DA) medial prefrontal cortex extracellular concentrations determined by intracerebral microdialysis. Different structural models were investigated to fit DA concentrations after QTP dosing, and the final model describes the synthesis, release, and elimination of DA using a pool compartment. The results show that nanoparticles increase QTP brain concentrations and DA peak after drug dosing to SPR. To the best of our knowledge, this is the first study that combines microdialysis and PK/PD modeling in a neurodevelopmental model of SCZ to investigate how a nanocarrier can modulate drug PK and PD, contributing to the development of new treatment strategies for SCZ.

Multi-virulence of Campylobacter jejuni carried by chicken meat in Brazil.

Campylobacter jejuni is the most frequent cause of bacterial gastroenteritis; therefore, the characteristics of its epidemiology must be continuously investigated to support possible mitigating measures. This is particularly important when evaluating representative strains from the world's leading chicken meat exporter, Brazil. We evaluated a panel of 14 virulence genes in 359 strains of C. jejuni isolated from chilled broiler carcasses in Brazil. The genes were classified into five virulence categories (B: biofilm/motility; SS: secretion/cytotoxicity system; CI: invasion/colonization; GB: Guillain-Barré; and AE: adaptation to stress). The percentage of strains with stress adaptation genes (86.07%) indicates the ability to survive in unfavorable environments; in addition, the strains showed a risk of causing infections in humans due to the frequency of the hcp gene (97.77%). Genes related to Guillain-Barre syndrome (GBS) in 77.44% of strains are an additional concern, which must be monitored. The gene panel showed the presence of 124 virulence profiles. Individual analyses by carcass, slaughter establishment, and municipalities in which they were located showed high index variabilities (I.Var.) of 0.82, 0.87, and 0.78, respectively. Georeferencing indicated the state of Paraná as a hotspot for virulent strains. Higher levels of isolation and multi-virulence were identified in the summer, which is hot and humid in Brazil. Together, our results showed that the studied strains are a potential danger to public health and that there is an urgent need for their surveillance and the adoption of control measures, especially in the state of Paraná.

Population Pharmacokinetic Modeling of Free Plasma and Free Brain Concentrations of Ceftaroline in Healthy and Methicillin-Resistant Staphylococcus aureus-Infected Wistar Rats.

A population pharmacokinetic model was developed to describe alterations in ceftaroline brain disposition caused by meningitis in healthy and methicillin-resistant Staphylococcus aureus (MRSA)-infected rats. Blood and brain microdialysate samples were obtained after a single bolus dose of ceftaroline fosamil (20 mg/kg) administered intravenously. Plasma data were modeled as one compartment, and brain data were added to the model as a second compartment, with bidirectional drug transport between plasma and brain (Qin and Qout). The cardiac output (CO) of the animals showed a significant correlation with the relative recovery (RR) of plasma microdialysis probes, with animals with greater CO presenting lower RR values. The Qin was approximately 60% higher in infected animals, leading to greater brain exposure to ceftaroline. Ceftaroline brain penetration was influenced by MRSA infection, increasing from 17% (Qin/Qout) in healthy animals to 27% in infected animals. Simulations of a 2-h intravenous infusion of 50 mg/kg every 8 h achieved >90% probability of target attainment (PTA) in plasma and brain for the modal MRSA MIC (0.25 mg/L), suggesting that the drug should be considered an option for treating central nervous system infections.

Validation of a MALDI-TOF MS Method for SARS-CoV-2 Detection on the Bruker Biotyper and Nasopharyngeal Swabs: A Brazil-UK Collaborative Study.

We developed a MALDI-TOF mass spectrometry method for the detection of the SARS-CoV-2 virus in saliva-gargle samples using Shimadzu MALDI-TOF mass spectrometers in the UK. This was validated in the USA to CLIA-LDT standards for asymptomatic infection detection remotely via sharing protocols, shipping key reagents, video conferencing, and data exchange. In Brazil, more so than in the UK and USA, there is a need to develop non-PCR-dependent, rapid, and affordable SARS-CoV-2 infection screening tests that also identify variant SARS-CoV-2 and other virus infections. In addition, travel restrictions necessitated remote collaboration with validation on the available clinical MALDI-TOF-the Bruker Biotyper (microflex® LT/SH)-and on nasopharyngeal swab samples, as salivary gargle samples were not available. The Bruker Biotyper was shown to be almost log103 more sensitive at the detection of high molecular weight spike proteins. A protocol for saline swab soaks out was developed, and duplicate swab samples collected in Brazil were analyzed by MALDI-TOF MS. The swab collected sample spectra that varied from that of saliva-gargle in three additional mass peaks in the mass region expected for IgG heavy chains and human serum albumin. A subset of clinical samples with additional high mass, probably spike-related proteins, were also found. Further, spectral data comparisons and analysis, subjected to machine learning algorithms in order to resolve RT-qPCR positive from RT-qPCR negative swab samples, showed 56-62% sensitivity, 87-91% specificity, and a 78% agreement with RT-qPCR scoring for SARS-CoV-2 infection.

Development and validation of an LC-MS/MS method to quantify ceftaroline in microdialysate samples from plasma and brain: Application to a preclinical pharmacokinetic investigation.

A bioanalytical LC-MS/MS method was developed and validated to determine ceftaroline in microdialysate samples from plasma and brain. Ceftaroline was separated using a C18 column and a mobile phase consisting of water and acetonitrile, both with 5 mM of ammonium formate and acid formic 0.1%, eluted as gradient. Ceftaroline was monitored using electrospray ionization operating on positive mode (ESI+) monitoring the transition 604.89 > 209.3 m/z. The method showed linearity in the concentration range of 0.5-500 ng/mL for brain microdialysate and 0.5-2500 ng/mL for plasma microdialysate with coefficients of determination ≥0.997. The inter-and intra-day precision, the accuracy, and the stability of the drug in different conditions were in accordance with the acceptable limits determined by international guidelines. Plasma pharmacokinetics and brain distribution of the drug were carried out after intravenous administration of 20 mg/kg of ceftaroline to male Wistar rats. The estimated geometric mean (geometric coefficient of variation) area under the curve (AUC0-∞) was 4.68 (45.8%) mg·h/L and 1.20 (54.2%) mg·h/L for plasma and brain, respectively, resulting in a brain exposure of about 33% (AUCfree brain/AUCfree plasma). The results indicate that ceftaroline presents good penetration in the brain when considering free plasma and free brain concentrations.

Multi-residue methodology for quantification of antiparasitics in hen eggs by LC-MS/MS: development, validation and application to 348 samples from Brazil.

Analytical methodology for quantification of 15 antiparasitic drugs and their respective metabolites in laying hen eggs was optimized and validated. The method uses acetonitrile as solvent extraction, sodium chloride for salting-out, low-temperature purification and analysis by LC-MS/MS. A total of 348 egg samples were collected in 11 states of Brazil and 50% of the total samples presented antiparasitic residues, which were albendazole, fipronil, fenbendazole, ivermectin, oxibendazole and mebendazole. A total of 12.4% of the samples were considered non-compliant, and residues quantified in these samples were albendazole, fipronil, and mebendazole. Albendazole was always identified as albendazole sulfone. Only one sample presented fipronil and fipronil sulfone; all others exclusively the sulfone metabolite. Fenbendazole was characterized by the presence of both metabolites: sulfone and sulfoxide. Maximum limits adopted are based on the Normative Instruction 51/2019 of the Brazilian Health Regulatory Agency (ANVISA), but albendazole, fipronil, oxibendazole, ivermectin, and mebendazole do not have their maximum residue level established. In addition, metabolites of albendazole, fipronil and fenbendazole in eggs are not considered in this Instruction.

Probability of Target Attainment of Tobramycin Treatment in Acute and Chronic Pseudomonas aeruginosa Lung Infection Based on Preclinical Population Pharmacokinetic Modeling.

Biofilms and infectious process may alter free antimicrobial concentrations at the site of infection. Tobramycin (TOB), an aminoglycoside used to treat lung infections caused by Pseudomonas aeruginosa, binds to alginate present in biofilm extracellular matrix increasing its minimum inhibitory concentration (MIC). This work aimed to investigate the impact of biofilm-forming P. aeruginosa infection on TOB lung and epithelial lining fluid (ELF) penetration, using microdialysis, and to develop a population pharmacokinetic (popPK) model to evaluate the probability of therapeutic target attainment of current dosing regimens employed in fibrocystic and non-fibrocystic patients. The popPK model developed has three compartments including the lung. The ELF concentrations were described by a penetration factor derived from the lung compartment. Infection was a covariate in lung volume (V3) and only chronic infection was a covariate in central volume (V1) and total clearance (CL). Simulations of the recommended treatments for acute and chronic infection achieved >90% probability of target attainment (PTA) in the lung with 4.5 mg/kg q24h and 11 mg/kg q24h, respectively, for the most prevalent P. aeruginosa MIC (0.5 mg/mL). The popPK model was successfully applied to evaluate the PTA of current TOB dosing regimens used in the clinic, indicating the need to investigate alternative posology.

Residues of Veterinary Drugs in Animal Products Commercialized in the Border Region of Brazil, Argentina, and Uruguay.

ABSTRACT: The traffic in international animal products can become a public health hazard when legal import sanitary procedures are not followed. In Brazil, due to its extensive border area, the importation of animal products is a common practice in many areas, especially in Rio Grande do Sul, a state that borders Argentina and Uruguay. The objective of this study was to evaluate the presence of veterinary drug residues (antibiotics and antiparasitics) in animal products consumed in Rio Grande do Sul. The presence of residues of veterinary antibiotics and antiparasitics was assessed in 189 meat (beef, pork, and chicken), processed dairy, and meat product samples bought in Argentina (n = 90) and Uruguay (n = 99). Residues of these veterinary drugs were detected in 50 (26.45%) of the samples; 28 samples (14.81%) had antibiotic residues, and 22 samples (11.64%) had antiparasitic residues. Of the 50 positive samples, 40% (15 from Argentina and 5 from Uruguay) had residues above the maximum residue limits (MRLs). Of these 20 samples, 12 had antiparasitic residues above the MRLs (11 beef samples had ivermectin and 1 pork sample had ivermectin and doramectin) and 8 had antibiotic residues above the MRLs (2 pork and 2 sausage samples had doxycycline, 2 cheese samples had doxycycline and chlortetracycline, 1 poultry meat sample had chloramphenicol, and 1 cheese sample had monensin). Because of the potential toxic effects on humans and the potential for pathogens to develop antibiotic resistance, the presence of these residues above the MRLs is a potential risk to public health. The negative impact of consumption of imported animal products can be reduced by implementation of an effective surveillance system and educational campaigns for the general population.

Quantification of pyrrolizidine alkaloids in Senecio brasiliensis, beehive pollen, and honey by LC-MS/MS.

This article presents the determination of eight pyrrolizidine alkaloids (PAs) by LC-MS/MS in honeys, pollen, and Senecio brasiliensis (Asteraceae) samples, all from Santa Catarina state, Brazil. In addition, the Box-Behnken design was used to perform an optimized sample preparation on pollens and S. brasiliensis parts. Senecionine and its N-oxide, besides retrorsine N-oxide, were determined in six of the seven honeys samples. Pollen from species of the Asteraceae, Fabaceae, and Boraginaceae families were found with greater predominance in three of the seven honeys samples. In these three honeys samples were also found the highest PAs levels. In beehive pollen, flower, and leaf of S. brasiliensis, the total levels of PAs and their N-oxides reached 221, 14.1 × 104, and 14.8 × 104 mg kg-1, respectively. In honeys, these compounds are chemical contaminants and therefore undesirable when the sum exceeds 71 µg kg-1, according to EFSA. On the other hand, although PAs are naturally present in plant and pollen of some species (Senecio, Crotalaria, Bacharis, Ecchium, Mimosa scabrella, Vernonia), it is important to monitor their levels in plants but also in honeys, and other beehive products since these compounds are transferred to the final product.

Dermatopharmacokinetic and pharmacodynamic evaluation of a novel nanostructured formulation containing capsaicinoids for treating neuropathic pain.

The in vivo skin penetration by dermal microdialysis and the pharmacological efficacy of a chitosan hydrogel containing capsaicinoids-loaded nanocapsules (CHNCCaps) was evaluated in this study. Such gel has previously been proven to control capsaicinoids release and decrease the drugs side effects in humans. The nanocapsules containing capsaicinoids had an average size around 150 nm, with a low polydispersity index, positive zeta potential, and high encapsulation efficiency of the drugs. The CHNCCaps showed intact nanocapsules, a slightly acid pH value, and a pseudoplastic behavior suitable for topical application. Microdialysis experiments showed a 1.6-fold increase in the concentration of capsaicinoids in the dermis (after 12 h of its application) when CHNCCaps was administered compared to a chitosan hydrogel containing capsaicinoids in hydroethanolic solution (CHETCaps) and the commercial cream. The CHNCCaps showed antiallodynic and antihyperalgesic effects from 6 h to 96 h after treatment initiation, whereas CHETCaps and the commercial cream showed antiallodynic and antihyperalgesic effects only at 48 h and 96 h after treatment initiation, respectively. CHNCCaps and the commercial cream maintained antihyperalgesic activity for 6 days after treatment interruption. For mechanical allodynia, the antinociceptive effect was maintained for 48 h after treatment interruption only with CHNCCaps. In conclusion, CHNCCaps is a promising formulation for treating peripheral neuropathic pain.

Lisdexamfetamine and amphetamine pharmacokinetics in oral fluid, plasma, and urine after controlled oral administration of lisdexamfetamine.

Lisdexamfetamine (LDX) is a long-acting prodrug stimulant indicated for the treatment of attention-deficit/hyperactivity disorder (ADHD) and binge-eating disorder (BED) symptoms. In vivo hydrolysis of the LDX amide bond releases the therapeutically active d-amphetamine (d-AMPH). This study aims to describe the pharmacokinetics of LDX and its major metabolite d-AMPH in human oral fluid, urine and plasma after a single 70 mg oral dose of LDX dimesylate. Six volunteers participated in the study. Oral fluid and blood samples were collected for up to 72 h and urine for up to 120 h post-drug administration for the pharmacokinetic evaluation of intact LDX and d-AMPH. Samples were analyzed by LC-MS/MS. Regarding noncompartmental analysis, d-AMPH reached the maximum concentration at 3.8 and 4 h post-administration in plasma and oral fluid, respectively, with a mean peak concentration value almost six-fold higher in oral fluid. LDX reached maximum concentration at 1.2 and 1.8 h post-administration in plasma and oral fluid, respectively, with a mean peak concentration value almost three-fold higher in plasma. Intact LDX and d-AMPH were detected in the three matrices. The best fit of compartmental analysis was found in the one-compartment model for both analytes in plasma and oral fluid. There was a correlation between oral fluid and plasma d-AMPH concentrations and between parent to metabolite concentration ratios over time in plasma as well as in oral fluid.

Retention of vitamin A after goat milk processing into cheese: a nutritional strategy.

The deficiency in micronutrients is a public health problem, principally in lower-middle-income countries. Vitamin A (VA) is considered a micronutrient fundamental to the maintenance and development of different tissues in the organism. Therefore, it is an essential micronutrient in the human diet. In these terms, goat milk is the leading food consumed to provide nutritional support in innumerous lower-middle-income countries. Here our work aimed to produce goat cheese studying strategies to promote the retention of VA. Our experiment design also explores the use of the salting process to evaluate the levels of VA retention. The level of VA in goat cheese was determined using LC-MS/MS analysis. Additionally, the redox status of the goat cheese in terms of lipid peroxidation and protein oxidation was determined. The texture analysis was also evaluated to verify if the redox status and salting process influence the texture profile. The results showed that the salting process during goat cheese production improves the retention of VA in goat cheese. Moreover, the salting process also is related to alterations in the status redox of the goat cheese and texture parameters. Therefore, our results show that goat cheese production can be an alternative to produced dairy derivates with recognized concentrations of VA for human nutrition.

Quantification of neurotransmitters in microdialysate samples following quetiapine dosing to schizophrenia phenotyped rats using a validated LC-MS/MS method.

A versatile method was developed and validated for simultaneous determination of the monoamine neurotransmitters (MNT) dopamine (DA), 3-4-dyhydroxyphenilacetic acid (DOPAC), homovanilic acid (HVA), serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) in rat brain microdialysate samples using high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The method allowed for small sample volume, using positive and negative ionization mode in a single run analysis without any derivatization or cleanup steps. Analytes were quantified at concentrations ranging from 100 ng/mL to 0.05, 10, 0.5, 0.1 or 1 ng/mL (lower limit of quantification, LLOQ) of DA, DOPAC, HVA, 5-HT and 5-HIAA, respectively, showing linearity (r > 0.98), accuracy, and precision (R.S.D ± 15%) according to validation limits accepted by international guidelines. The method was successfully applied for monitoring the concentration changes of MNT in microdialysate samples from medium prefrontal cortex of Wistar rats in a neurodevelopmental model of schizophrenia before and after quetiapine 5 mg/kg i.v. bolus dose administration. No alterations in MNTs were observed in schizophrenia phenotyped rats (SPR) in comparison to the baseline shading a light on the limited response rate to antipsychotic drugs observed in chronic schizophrenic patients.

A liquid chromatography coupled to quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS) method for identification analysis of saponins from Quillaja saponaria bark extracts in foot-and-mouth disease vaccines: Development, validation and applicability.

Saponins from Quillaja saponaria have been commonly used as immunomodulatory adjuvants in foot-and-mouth disease vaccines (FMDVs). However, due to the lack of consensus over the possible exacerbation of local inflammatory responses in cattle and its economic impacts, their use has been discouraged by Brazilian authorities. A qualitative method intended to determine the presence of saponins from Q. saponaria bark extracts in FMDVs was developed and validated. Instrumental analysis was performed using an liquid chromatography (LC) coupled to a quadrupole-time-of-flight-mass spectrometry (TOF-MS) system. The method was validated according to the International Conference on Harmonization Harmonized Tripartite Guideline Q2 (R1) and Brazilian Ministry of Agriculture, Livestock and Food Supply Analytical Quality Assurance Guidelines. Validation parameters were determined and considered suitable to the established criteria. The validated method has been applied in routine analysis in the National Agricultural Laboratory at Rio Grande do Sul (LANAGRO-RS). All results obtained were in agreement with the vaccine's composition described by the manufacturer. The method is easy and adequate for analysis in routine laboratories. To the best of the authors' knowledge, this is the first report of a method which intends to investigate the presence of saponins from Q. saponaria bark extracts in veterinary vaccines.

The effect of breed, sex, and drug concentration on the pharmacokinetic profile of ivermectin in cattle.

Ivermectin (IVM) is one of the most widely used antiparasitic drugs worldwide and has become the drug of choice for anthelmintic and tick treatment in beef cattle production. It is known that pharmacokinetic parameters are fundamental to the rational use of a drug and food safety and these parameters are influenced by different factors. The aim of this study was to evaluate the pharmacokinetic profile of IVM in Bos indicus, Bos taurus, and crossbreed cattle (B. indicus × B. taurus) kept under same field conditions and the possible impacts of sex and IVM formulation (1% and 3.15%). It was observed that IVM concentration was significantly affected by breed. The plasma concentrations of IVM, AUC, Cmax , and t1/2ß were significantly higher in B. indicus compared to B. taurus. Crossbreed animals showed an intermediate profile between European and Indian cattle. No alteration in pharmacokinetics parameters was detected when comparing different gender. Concerning the pharmacokinetic data of IVM formulation, it was verified that Tmax , AUC, and t1/2ß were higher in 3.15% IVM animals than those from 1% IVM formulation. The results clearly indicated that the IVM plasma concentrations in B. indicus were higher than that in B. taurus.

High-performance method to detection of Klebsiella pneumoniae Carbapenemase in Enterobacterales by LC-MS/MS.

Carbapenem-resistant Enterobacterales (CREs) have been recognized as an important threat to global health. CRE cause the majority of the difficult-to-treat infections in health-care settings and are associated with high mortality. Klebsiella pneumoniae carbapenemase (KPC)-producing CREs, in particular Klebsiella pneumoniae, are globally disseminated and responsible for a large number of outbreaks. Development of rapid methods for KPC detection can provide great clinical and epidemiological benefits to prevent KPC dissemination. The aim of this study was to standardize and validate a LC-MS/MS method to detect KPC. This method was also tested against a broad variety of species, including CRE with other carbapenemase genes and the recently reported mcr-1. For validation, 111 isolates with reduced susceptibility to carbapenems were selected (49 KPC-positive and 62 KPC-negative). The presence of four tryptic peptides related to the KPC enzyme was evaluated, and the identification of at least two of them classified the isolate as "KPC-positive." The LTLGSALAAPQR and LALEGLGVNGQ peptides were both detected in 47 of 49 isolates with the blaKPC gene. The other two peptides, GFLAAAVLAR and APIVLAVYTR, were detected in 46 and 19 isolates with the blaKPC gene, respectively. The method correctly classified 47 of 49 KPC-positive and all KPC-negative isolates yielding 96.07% of sensitivity and 100% of specificity. In conclusion, our results demonstrate that the KPC peptide markers were robustly detected by the method which presented high sensitivity and full specificity and therefore can be used as a reliable method to identify this resistance mechanism.

Rapid and sensitive LC-MS/MS method for simultaneous quantification of capsaicin and dihydrocapsaicin in microdialysis samples following dermal application.

A bioanalytical LC-MS/MS method was developed and validated for the simultaneous quantification of capsaicin (CAPS) and dihydrocapsaicin (D-CAPS) in dermal microdialysis samples from rats. Capsaicinoids were separated by using a C18 column, with a mobile phase of water and acetonitrile, both with 0.1% of formic acid, eluted as a gradient. Compounds were detected by using an electrospray ionization source operating in the positive mode (ESI+) to monitor the m/z transitions of 306.1 > 137.0 for CAPS and 308.1 > 137.0 for D-CAPS. The method showed linearity in the concentration range of 0.5-100 ng/ml for CAPS and 0.25-100 ng/ml for D-CAPS, with coefficients of determination of ≥ 0.99. The inter- and intra-day precision, accuracy, and compound stability in different conditions were in accordance with the limits established by the US Food and Drug Administration guidelines. The recovery of the drugs by microdialysis were dependent on the flow rate, but independent of drug concentration. For CAPS, calibration of the in vitro microdialysis probes by dialysis and retrodialysis resulted in statistically similar drug recovery of 68.5% ± 5.9% and 77.8% ± 6.6%, respectively, at a flow rate of 0.5 µl/min. For D-CAPS, the recovery by dialysis was lower than by retrodialysis, at 51.4% ± 6.6% and 92.6% ± 2.4%, respectively. This difference was attributed to the binding of D-CAPS to the plastic tubing, which was experimentally evaluated and mathematically modeled. In vivo recoveries were 75.7% ± 6.3% for CAPS and 81.9% ± 1.5% for D-CAPS at the same flow rate. The analytical method showed high specificity, accuracy, and sensitivity, and suitability for dermatopharmacokinetic studies. These results will allow the determination of the actual free concentration of these drugs in dermatopharmacokinetic experiments, as shown in a pilot experiment with a commercial cream containing capsaicinoids.

The effects of retinol oral supplementation in 6-hydroxydopamine dopaminergic denervation model in Wistar rats.

Vitamin A (retinol) is involved in signaling pathways regulating gene expression and was postulated to be a major antioxidant and anti-inflammatory compound of the diet. Parkinson's disease (PD) is a progressive neurodegenerative disorder, characterized by loss of nigral dopaminergic neurons, involving oxidative stress and pro-inflammatory activation. The aim of the present study was to evaluate the neuroprotective effects of retinol oral supplementation against 6-hydroxydopamine (6-OHDA, 12 µg per rat) nigrostriatal dopaminergic denervation in Wistar rats. Animals supplemented with retinol (retinyl palmitate, 3000 IU/kg/day) during 28 days exhibited increased retinol content in liver, although circulating retinol levels (serum) were unaltered. Retinol supplementation did not protect against the loss of dopaminergic neurons (assessed through tyrosine hydroxylase immunofluorescence and Western blot). Retinol supplementation prevented the effect of 6-OHDA on Iba-1 levels but had no effect on 6-OHDA-induced GFAP increase. Moreover, GFAP levels were increased by retinol supplementation alone. Rats pre-treated with retinol did not present oxidative damage or thiol redox modifications in liver, and the circulating levels of TNF-α, IL-1ß, IL-6 and IL-10 were unaltered by retinol supplementation, demonstrating that the protocol used here did not cause systemic toxicity to animals. Our results indicate that oral retinol supplementation is not able to protect against 6-OHDA-induced dopaminergic denervation, and it may actually stimulate astrocyte reactivity without altering parameters of systemic toxicity.

An LC-ESI-MS/MS method for residues of fluoroquinolones, sulfonamides, tetracyclines and trimethoprim in feedingstuffs: validation and surveillance.

An increasing concern about food safety has been observed over the years. The presence of drugs residues in food is one of the major subjects of research in food safety. Feedingstuffs can be responsible for carryover into the food chain of residues of several drugs. This paper describes the development, validation and application of a fast and simple method for analysis of 24 antibiotic residues in feedingstuffs for cattle, pigs and poultry. Analytes include compounds from different antimicrobials classes, such as sulfonamides (sulfadiazine, sulfamethazine, sulfamethoxazole, sulfaquinoxaline, sulfachlorpyridazine, sulfadoxine, sulfadimethoxine, sulfizoxazole, sulfamerazine and sulfathiazole), fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin, danofloxacin, difloxacin, sarafloxacin, flumequine, nalidixic acid and oxolinic acid), tetracyclines (tetracycline, doxycycline, oxytetracycline and chlortetracycline) and trimethoprim. Samples were extracted with methanol:water (70:30) 0.1% formic acid, followed by clean-up steps using centrifugation, low-temperature purification (LTP) and ultracentrifugation. Instrumental analysis was performed using liquid chromatography coupled to tandem mass spectrometry. Chromatographic separation was achieved using a C18 column and a mobile phase composed of acetonitrile and water, both with 0.1% formic acid. Validation parameters such as limit of detection (LOD), limit of quantification (LOQ), selectivity, linearity, accuracy, precision, decision limit (CCα) and detection capability (CCß) were determined and meet the adopted criteria. LOD and LOQ were set to 30 and 75 µg kg-1, respectively. Inter-day precision were in the range from 4.0 to 11.1%, and linearity provides values of r2 above 0.95 for all analytes. The optimised method was applied to the analysis of more than 1500 real samples within the period 2012-2017. Non-compliant results were discussed and classified in terms of analytes, feed types and target species. Multivariate analysis of the data was performed using principal component analysis.

Effects of methylmercury and retinol palmitate co-administration in rats during pregnancy and breastfeeding: Metabolic and redox parameters in dams and their offspring.

Ubiquitous low-dose methylmercury (MeHg) exposure through an increased fish consumption represents a global public health problem, especially among pregnant women. A plethora of micronutrients presented in fish affects MeHg uptake/distribution, but limited data is available. Vitamin A (VitA), another fish micronutrient is used in nutritional supplementation, especially during pregnancy. However, there is no information about the health effects arising from their combined exposure. Therefore, the present study aimed to examine the effects of both MeHg and retinyl palmitate administered on pregnant and lactating rats in metabolic and redox parameters from dams and their offspring. Thirty Wistar female rats were orally supplemented with MeHg (0,5 mg/kg/day) and retinyl palmitate (7500 µg RAE/kg/day) via gavage, either individually or in combination from the gestational day 0 to weaning. For dams (150 days old) and their offspring (31 days old), glycogen accumulation (hepatic and cardiac) and retinoid contents (plasma and liver) were analyzed. Hg deposition in liver tissue was quantified. Redox parameters (liver, kidney, and heart) were evaluated for both animals. Cytogenetic damage was analyzed with micronucleus test. Our results showed no general toxic or metabolic alterations in dams and their offspring by MeHg-VitA co-administration during pregnancy and lactation. However, increased lipoperoxidation in maternal liver and a disrupted pro-oxidant response in the heart of male pups was encountered, with apparently no particular effects in the antioxidant response in female offspring. GST activity in dam kidney was altered leading to possible redox disruption of this tissue with no alterations in offspring. Finally, the genomic damage was exacerbated in both male and female pups. In conclusion, low-dose MeHg exposure and retinyl palmitate supplementation during gestation and lactation produced a potentiated pro-oxidant effect, which was tissue-specific. Although this is a pre-clinical approach, we recommend precaution for pregnant women regarding food consumption, and we encourage more epidemiological studies to assess possible modulations effects of MeHg-VitA co-administration at safe or inadvertently used doses in humans, which may be related to specific pathologies in mothers and their children.