Determination of meropenem in capillary plasma microsamples using LC-MS/MS

Background: The measurement of meropenem plasma concentrations is employed for dosing regimen individualization. The aim of this study was to develop and validate a LC-MS/MS assay for quantification of meropenem in capillary plasma microsamples. Methods: Samples were prepared by protein precipitation with acetonitrile, followed by clean-up with dichloromethane. The method was validated and applied to 12 paired samples of venous and capillary plasma. Results: The method was linear in the range of 0.5-50 μg/ml. Matrix effects were minimal. Inter- and intra-assay were 3.8-7.9% and 2.7-5.5%, respectively, while accuracy was 91.7-100.6%. Concentrations in capillary and venous plasma were highly correlated. Conclusion: An assay for the quantification of meropenem in capillary plasma microsamples was fully validated, showing potential for clinical application.

Determination of carbamazepine in fingerprints: a feasibility study to evaluate adherence in epilepsy patients

Background: Fingerprint drug concentrations can be used as a noninvasive and convenient alternative to evaluate adherence to pharmacotherapy. Methods: Fingerprints were applied over glass slides, extracted and analyzed by ultra-high performance LC-MS/MS. The assay and drug adherence questionnaires were applied to 30 epilepsy patients. Results: The assay had linearity in the range 0.05-10 ng fingerprint-1, with precision of 2.16-7.9% and accuracy of 95.0-102.8%. Carbamazepine (CBZ) levels in fingerprints were stable at 45°C for 15 days. Concentrations in patient samples were 0.06-9.28 ng fingerprint-1. A significant difference (p = 0.003) was found between CBZ concentrations in fingerprints between patient groups divided as low and medium/high adherence. Conclusion: This method can potentially be applied to the identification of epilepsy patients with low adherence to CBZ pharmacotherapy.

rAAV-compatible human mini promoters enhance transgene expression in rat retinal ganglion cells

Recombinant adeno-associated viral vectors (rAAV) are the safest and most effective gene delivery platform to drive the treatment of many inherited eye disorders in well-characterized animal models. The use in rAAV of ubiquitous promoters derived from viral sequences such as CMV/CBA (chicken β-actin promoter with cytomegalovirus enhancer) can lead to unwanted side effects such as pro-inflammatory immune responses and retinal cytotoxicity, thus reducing therapy efficacy. Thus, an advance in gene therapy is the availability of small promoters, that potentiate and direct gene expression to the cell type of interest, with higher safety and efficacy. In this study, we used six human mini-promoters packaged in rAAV2 quadruple mutant (Y-F) to test for transduction of the rat retina after intravitreal injection. After four weeks, immunohistochemical analysis detected GFP-labeled cells in the ganglion cell layer (GCL) for all constructs tested. Among them, Ple25sh1, Ple25sh2 and Ple53 promoted a widespread reporter-transgene expression in the GCL, with an increased number of GFP-expressing retinal ganglion cells when compared with the CMV/CBA vector. Moreover, Ple53 provided the strongest levels of GFP fluorescence in both cell soma and axons of retinal ganglion cells (RGCs) without any detectable adverse effects in retina function. Remarkably, a nearly 50-fold reduction in the number of intravitreally injected vector particles containing Ple53 promoter, still attained levels of transgene expression similar to CMV/CBA. Thus, the tested MiniPs show great potential for protocols of retinal gene therapy in therapeutic applications for retinal degenerations, especially those involving RGC-related disorders such as glaucoma.

Caenorhabditis elegans as a suitable model to evaluate the toxicity of water from Rolante River, southern Brazil

Urbanization and agricultural activities increased environmental contaminants. Integrated analysis of water parameters and bioassays represents an essential approach to evaluating aquatic resource quality. This study aimed to assess water quality by microbiological and physicochemical parameters as well as the toxicological effects of water samples on the Ames test and Caenorhabditis elegans model. Samples were collected during (collection 1) and after (collection 2) pesticide application in the upper (S1), middle (S2), and lower (S3) sections of the Rolante River, southern Brazil. Metals were determined by GFAAS and pesticides by UPLC-MS/MS. Bioassays using the Ames test and the nematode C. elegans were performed. Levels of microbiological parameters, as well as Mn and Cu were higher than the maximum allowed limits established by legislation in collection 2 compared to collection 1. The presence of pesticide was observed in both collections; higher levels were found in collection 1. No mutagenic effect was detected. Significant inhibition of body length of C. elegans was found in collection 1 at S2 (P < 0.001) and S3 (P < 0.001) and in collection 2 at S2 (P = 0.004). Comparing the same sampling site between collections, a significant difference was found between the site of collection (F(3,6)=8.75, P = 0.01) and the time of collection (F(1,2)=28.61, P = 0.03), for the S2 and S3 samples. C. elegans model was useful for assessing surface water quality/toxicity. Results suggest that an integrated analysis for the surface water status could be beneficial for future approaches.

Unraveling gene expression and genetic instability in dental fluorosis: Investigating the impact of chronic fluoride exposure

Chronic fluoride exposure, even in small quantities, when continuously ingested by the human population, can lead to a significant public health concern known as fluorosis. Our understanding of the effects of fluoride on human health, as well as its potential to impact DNA, is limited. The present study aimed to assess genetic instability in 20 individuals diagnosed with dental fluorosis and 20 individuals without the condition from the state of Rio Grande do Sul, Brazil. The participants' dental fluorosis was evaluated using the Thylstrup-Fejerskov index (TF). To further evaluate genetic instability, several assays were conducted, including the alkaline and modified (+FPG) comet assay (using a visual score, VS), the buccal micronucleus (MN) cytome (BMCyt) assay, the cytokinesis-block MN (CBMN-Cyt) assay, and the measurement of telomere length (TL). In addition, the study utilized tools from Systems Biology to gain insights into the effects of fluoride exposure on humans, which aided in the selection and evaluation of mRNA expression levels of specific genes, namely PPA1 (inorganic pyrophosphatase 1), AQP5 (Aquaporin 5), and MT-ATP6 (Mitochondrially Encoded Adenosine Triphosphate Synthase Membrane Subunit 6). Furthermore, fluoride levels in the blood and urine were assessed using an ion-selective electrode, along with the evaluation of the inflammatory response in serum. The group with dental fluorosis exhibited 2.18 times higher MN frequencies specifically when assessed using the CBMN-Cyt assay, in comparison with individuals without fluorosis. Findings from the enzyme-modified comet assay indicated oxidative damage to purines in DNA. Furthermore, a decrease in TL was observed, along with elevated expression patterns of the PPA1 and AQP5 genes, and significant alterations in cytokine release. Significant correlations were identified between the TF and age, as well as the levels of necrotic cells. Additionally, noteworthy correlations were established between fluoride levels and the levels of MN, VS, and MT-ATP6. Although dental fluorosis results from fluoride exposure, our research highlights the potential influence of this condition on genomic instability and gene expression. Consequently, our findings stress the importance of continuously monitoring populations with a high incidence of dental fluorosis to enhance our comprehension of how genomic instability might correlate with the origins and consequences of health problems in these individuals.

Residual contamination in antineoplastic drug packaging

INTRODUCTION

The handling of antineoplastic drugs should follow strict supervision and safety rules to minimize the occupational exposure risks to professionals involved. The external surface contamination of drug vials is recognized as a health risk. So, our goal was to determine if there is residual contamination on the vials and containers surface of the antineoplastic drugs doxorubicin (DOX) and cyclophosphamide (CP).

METHODS

A cross-sectional study was conducted. Samples were collected using a uniform sampling procedure on the inner surfaces of the packages/boxes and the outer surfaces of the vials. The analyzes were executed by high-performance liquid chromatography/mass spectrometry (UHPLC-MS/MS).

RESULTS

A total of 209 samples were analyzed, 66 of CP and 143 of DOX. CP levels were detected in nine samples (13.63%), three were below the lower limit of quantification (LLQ) and the other six had contamination levels ranging from 1.24 to 28.04 ng/filter. DOX levels were detected in 36 samples (25.17%), two were below the LLQ and the others had levels between 1.32 and 664.84 ng/filter. The majority of samples with residual contamination were in vials (80.0%), however, boxes also showed contamination.

CONCLUSIONS

The results revealed the presence of residual contamination in the vials and packages of CP and DOX drugs. Although the residues found in each sample are small, special care should be taken in the handling and disposal of the antineoplastic drugs. The use of personal protective equipment is fundamental while handling the vials and packaging of cytotoxic drugs.

Risk assessment of a Brazilian urban population due to the exposure to pyrethroid insecticides during the COVID-19 pandemic using wastewater-based epidemiology

Pyrethroids are synthetic insecticides commonly used in agriculture and homes due to their low toxicity to mammals and effectiveness at low doses. However, exposure to pyrethroids can cause various symptoms, depending on the route of exposure. To measure human exposure to pyrethroids, researchers used wastewater-based epidemiology (WBE) with polar organic chemical integrative samplers (POCIS) sampling. This approach is a cost-effective and efficient way to assess exposure to pyrethroids. The study aimed to evaluate the exposure of an urban population in Brazil to pyrethroids during the COVID-19 pandemic using WBE with POCIS sampling. Researchers analyzed 3-phenoxybenzoic acid (3-PBA) in wastewater using passive sampling with POCIS, which was extracted with methanol and analyzed using UPLC-MS/MS. The range of CTWA concentrations of 3-PBA in wastewater was 24.3-298.2 ng L-1, with a mean value of 134 ± 76.5 ng L-1. The values were used to estimate the exposure of the population to pyrethroid insecticides. Three different conversion factors were applied to determine the range of exposure to at least 20 different pyrethroid insecticides. The exposure values ranged from 18.08 to 1441.49 mg day-1 per 1000 inhabitants. The toxicological risk posed to the exposed population was evaluated by calculating the WBE toxicological level (WBE-TL). Lambda-cyhalothrin was used as a reference for risk assessment, and the WBE-TL values for lambda-cyhalothrin ranged from 0.5 to 8.29 (considering the high CF). We compared mobility trends to 3-PBA exposure during the COVID-19 pandemic. The study highlighted the effectiveness of POCIS sampling in WBE and provided useful information for policymakers and regulatory agencies. POCIS sampling has practical advantages, including analyte pre-concentration, low operational cost, and ease of use. Overall, the study shows the importance of monitoring and understanding the exposure of the population to pyrethroid insecticides, especially during the pandemic when people may be spending more time at home.

Evaluation of dried blood spots as an alternative sampling strategy for 5-fluorouracil monitoring: From method development to clinical application

Therapeutic drug monitoring (TDM) of 5-Fluorouracil (5-FU) is strongly recommended because of its large inter-individual pharmacokinetic variability, narrow therapeutic window, and incidence of toxicity. However, there are several factors that limit the application of TDM in clinical settings. Considering the intrinsic advantages of dried microsamples, such as minimally invasive sampling, analyte stability, and cost-effective logistics, this study aimed to develop a method for the determination of 5-FU in dried blood spots (DBS) using ultra-high liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and to evaluate its clinical application. Sample preparation was based on an aqueous extraction followed by protein precipitation. Separation was performed in an Acquity UPLC® HSS C18 (150 ×2.1 mm, 1.8 µm), and the mobile phases were water and acetonitrile with 0.5% acetic acid. The total run time was 5.5 min. The method was linear from 100 to 2000 ng/mL, precise (maximum CV% of 7.5%), and accurate (98.3-115.4%). The average recovery was 70%. Blood hematocrit had a minimal impact on the assay. DBS samples were stable for 21 days at 4, 25, and 45 °C. A total of 40 paired samples of plasma, capillary DBS, and venous DBS were analyzed. Median 5-FU concentrations were 444.7, 637.0, and 499.7 ng/mL for plasma, capillary DBS, and venous DBS, respectively. Capillary and plasma concentrations were significantly correlated (r > 0.90), but there was a lack of agreement between the methods, as capillary DBS levels were on average 146% of plasma. Venous DBS corresponded to 110% of the measured plasma concentrations, with a strong correlation (r > 0.97) and agreement between the methods. Our study is the first to report the use of DBS samples to quantify 5-FU. Further studies are needed to establish whether capillary samples can replace plasma.

HTLV-1 p12 modulates the levels of prion protein (PrPC) in CD4+ T cells

Introduction

Infection with human T cell lymphotropic virus type 1 (HTLV-1) is endemic in Brazil and is linked with pro-inflammatory conditions including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic neuroinflammatory incapacitating disease that culminates in loss of motor functions. The mechanisms underlying the onset and progression of HAM/TSP are incompletely understood. Previous studies have demonstrated that inflammation and infectious agents can affect the expression of cellular prion protein (PrPC) in immune cells.

Methods

Here, we investigated whether HTLV-1 infection affected PrPC content in cell lines and primary CD4+cells in vitro using flow cytometry and western blot assays.

Results

We found that HTLV-1 infection decreased the expression levels of PrPC and HTLV-1 Orf I encoded p12, an endoplasmic reticulum resident protein also known to affect post-transcriptionally cellular proteins such as MHC-class I and the IL-2 receptor. In addition, we observed a reduced percentage of CD4+ T cells from infected individuals expressing PrPC, which was reflected by IFN type II but not IL-17 expression.

Discussion

These results suggested that PrPC downregulation, linked to both HTLV-1 p12 and IFN-γ expression in CD4+ cells, may play a role in the neuropathogenesis of HTLV-1 infection.

Determination of amphetamines, opioids, cocaine metabolites and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in urine using biocompatible solid-phase microextraction and ultra-performance LC-MS/MS

Background: Workplace drug testing primarily relies on urine analysis, targeting multiple compounds with varying physicochemical characteristics. Biocompatible solid-phase microextraction (BioSPME) is a miniaturized solid-phase extraction technique that enables the simultaneous extraction and preconcentration of analytes directly from the biological matrix. Methods: The BioSPME procedure consisted of the sequential extraction of 50-μl urine samples using LC Tips C18 in basic and acidic pH, followed by desorption with methanol and n-hexane, respectively. The extracts were analyzed by ultra-performance LC-MS/MS. Results: Intra-day precision was 1.2-8.6% and inter-day precision was 1.8-14.2%. Accuracy was 96.8-107.4%. The extraction yields were 62.8-109.4%. The matrix effects were -3.98% to 1%. Conclusion: BioSPME shows promise as an alternative method for preparing urine samples prior to drug measurement by ultra-performance LC-MS/MS.

Dried blood spot sampling for therapeutic drug monitoring: challenges and opportunities

INTRODUCTION

The use of dried blood spots (DBS) has gained interest in the field of therapeutic drug monitoring (TDM) due to its potential advantages, such as minimally invasive capillary blood collection, potential stabilization of drugs and metabolites at room or high temperatures, and lower biohazard, allowing for inexpensive storage and transportation. However, there are several drawbacks to the clinical use of DBS in TDM, mostly related to hematocrit (Hct) effects, differences between venous and capillary blood concentrations, among others, that must be evaluated during analytical and clinical method validation.

AREA COVERED

This review focuses on the most recent publications on the applications of DBS sampling for TDM (2016-2022), with a special focus on the challenges presented by this alternative sampling strategy, as well as the opportunities for clinical applications. Real-life studies presenting clinical applications were reviewed.

EXPERT OPINION

With the availability of method development and validation guidelines for DBS-based methods in TDM, higher levels of assay validation standardization have been achieved, expanding the clinical applications of DBS sampling in patient care. New sampling devices that overcome the limitations of classical DBS, such as the Hct effects, will further encourage the use of DBS in routine TDM.

Evaluation of the HealthID PSD microsampling device for the simultaneous determination of cholesterol, high-density lipoprotein, triglycerides, creatinine, and HbA1c in capillary blood

INTRODUCTION

The use of dried capillary microsamples for clinical chemistry testing is an interesting alternative to conventional phlebotomy. Sampling devices capable to produce plasma from whole blood application are particularly useful. The aim of this study was to validate theHealthID PSDmicrosampling device for the determination of cholesterol (CHOL), high-density lipoprotein (HDL), triglycerides (TRIG), creatinine (CRE), and glycated hemoglobin (HbA₁c) after collection of capillary blood.

METHODS

Dried blood and plasma extracts were analyzed using modified methods in an open-channel biochemistry analyzer. The plasma volume in the extracts was corrected by the concentration of chloride (CL). Linearity, imprecision, bias, stability, and comparability to conventional samples were evaluated.

RESULTS

Dried plasma assays presented total error (TE) within acceptable limits. The analytes were stable for up to 14 days at 40 °C. Predicted serum concentrations of CHO, HDL, TRI, and CRE and predicted whole blood levels of HbA₁c, using dried extracts measurements, did not presented systematic or proportional differences to serum and whole blood levels.

CONCLUSIONS

Dried sample extracts obtained with capillary blood applied to the HealthID PSD allowed the determination of CHO, HDL, TRI, CRE, and HbA₁c, as well as the calculation of LDL level, using only 5 drops of blood. This sampling strategy can be useful for population screening programs, particularly in Developing Countries.

Evaluation of UGT1A1 and CYP3A Genotyping and Single-Point Irinotecan and Metabolite Concentrations as Predictors of the Occurrence of Adverse Events in Cancer Treatment

PURPOSE

The variability on irinotecan (IRI) pharmacokinetics and toxicity has been attributed mostly to genetic variations in the UGT1A1 gene, responsible for conjugation of the active metabolite SN-38. Also, CYP3A mediates the formation of inactive oxidative metabolites of IRI. The association between the occurrence of severe adverse events, pharmacokinetics parameters, and UGT1A1 and CYP3A4 predicted phenotypes was evaluated, as the evaluation of [SN-38]/IRI dose ratio as predictor of severe adverse events.

METHODS

Forty-one patients undergoing IRI therapy were enrolled in the study. Blood samples were collected 15 min after the end of drug the infusion, for IRI, SN-38, SN-38G, bilirubin concentrations measurements, and UGT1A1 and CYP3A genotype estimation. Data on adverse event was reported.

RESULTS

Fifteen patients (36.5%) developed grade 3/4 adverse events. A total of 9.8% (n = 4) of the patients had UGT1A1 reduced activity phenotype, and 48.7% (n = 20) had UGT1A1 and 63.4% (n = 26) CYP3A intermediary phenotypes. Severe neutropenia and diarrhea were more prevalent in patients with reduced UGT1A1 in comparison with functional metabolism (50% and 75% versus 0% and 13%, respectively). SN-38 levels and its concentrations adjusted by IRI dose were significantly correlated to toxicity (rs = 0.31 (p = 0.05) and rs = 0.425 (p < 0.01)). The [SN-38]/IRI dose ratio had a ROC curve of 0.823 (95% CI 0.69-0.956) to detect any severe adverse event and 0.833 (95% CI 0.694-0.973) to detect severe diarrhea. The cut-off of 0.075 ng mL-1 mg-1 had 100% sensitivity and 65.7% specificity to predict severe diarrhea.

CONCLUSION

Our data confirmed the relevance of the pre-emptive genotypic information of UGT1A1. The [SN-38]/IRI ratio, measured 15 min after the end of the IRI infusion, was a strong predictor of severe toxicity and could be applied to minimize the burden of patients after IRI administration.

Evaluation of oxidative stress and its association with drug therapy in inpatients treated for cocaine dependence

The use of cocaine affects several systems and organs of the human body and the consumption of this substance leads to an increase in the production of reactive oxygen species, and to the reduction of antioxidant defenses. The aim of this study was to evaluate the oxidative stress (OS), biochemical and hematological parameters in patients hospitalized for treatment of cocaine addiction, comparing levels at hospital admission and discharge. Forty patients were included in the study. OS was evaluated using catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GPx), total antioxidant power (FRAP), malondialdehyde (MDA), and sulfhydryl group (GS). The medications used during hospitalization were registered and their influence on the parameters of OS was analyzed. After the hospitalization period, there was an increase in GGT levels, a reduction in SOD activity, and an increase in GPx activity and FRAP levels. Carbamazepine users had higher SOD values and lower FRAP values at hospital discharge. The use of chlorpromazine caused differences in creatinine and gamma-glutamyltransferase (GGT) serum leves, and the levels of glutamic oxalacetic transaminase (TGO), MDA, and FRAP were increased at hospital discharge. Haloperidol and thiamine during hospitalization interfered with alkaline phosphatase levels. The use of risperidone caused an increase in the levels of SOD, and folic acid use was associated with lower levels of GPx and higher levels of glutamic-pyruvic transaminase (TGP) and alkaline phosphatase. Drug rehabilitation treatment was effective in decreasing oxidative damage represented by the reduction of biological markers.

Evaluation of oxidative stress markers in ethanol users

Ethanol is a central nervous system depressant that is widely consumed worldwide. When consumed chronically, it may have several consequences to the organism, such as oxidative stress. Ethanol metabolism increases the production of oxidant molecules and its consumption may cause changes in enzymatic and non-enzymatic systems that maintain cellular homeostasis. The activity of endogenous enzymes and lipid peroxidation are altered in alcohol consumers. Therefore, this study aimed to evaluate oxidative stress parameters in ethanol users compared to a control group. For that, the activity of the enzymes superoxide dismutase, catalase, and glutathione peroxidase, the ferric reducing/antioxidant power (FRAP), and malondialdehyde were evaluated. The influence of the amount of ethanol consumed on the analyzed parameters was also verified. The group of alcohol users consisted of 52 volunteers, 85% male and 15% female, with a mean age of 41±13 years. The control group consisted of 50 non-drinkers, 40% male and 60% female, with a mean age of 50±10 years. There was a significant difference in superoxide dismutase (P<0.001) and malondialdehyde (P=0.007) measurements between groups, as both parameters were increased in the group of ethanol users. Because of the higher amount of ethanol consumed, there was an increase of the catalase activity parameters and gradual reduction of FRAP. Thus, the ethanol-consuming participants were most likely under oxidative stress.

Determination of Ethyl Glucuronide and Ethyl Sulfate in Dried Blood Spots by UHPLC-MS-MS: Method Validation and Assessment of Ethanol Exposure in Postmortem Samples from Road Traffic Victims

The determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in blood has been proposed in clinical and forensic applications to identify recent alcohol consumption. Also, there is a growing interest on the use of dried blood spots (DBS) in toxicological analysis, allowing increased stability of the analytes and simplifying sample transportation and storage. This study presents the development and validation of a method for quantifying EtG and EtS in DBS using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS). The DBS samples were extracted with a mixture of methanol and acetonitrile (80:20 v/v) and analyzed using UHPLC-MS-MS with electrospray source in negative mode, after separation with a fluoro-phenyl stationary phase. Validation was performed according to the Scientific Working Group for Forensic Toxicology (SWGTOX) guidelines, with calibrations ranging from 0.10 to 18 µg/mL for EtG and 0.02 to 6 µg/mL for EtS. The analytes were stable in DBS stored from -20 to 45°C for 21 days. The method was successfully applied to capillary and venous DBS samples from 20 volunteers after ethanol ingestion and to DBS samples from 99 fatal victims of road traffic injuries. Capillary DBS was comparable to venous DBS and fresh whole blood in Passing-Bablok and Bland-Altman analysis, with correlation coefficients >0.91 (P < 0.001) for all comparisons. In postmortem application, the DBS EtG and EtS analysis indicated positive exposure to ethanol in 72.7% of the cases (EtG: 0.10-24.0 µg/mL and EtS: 0.03-4.11 µg/mL). The identification of ethanol consumption from blood alcohol concentrations (BACs) and EtG/EtS in DBS was in agreement in 98.6% of positive and 96.3% of negative cases (kappa 0.877, P < 0.001), indicating a high level of concordance with BAC in assessing alcohol use in postmortem samples.

DETERMINAÇÃO DE FOSFATIDILETANOL EM MANCHAS DE SANGUE SECO EM PAPEL POR UHPLC-MS/MS: AVALIAÇÃO DO CONSUMO DE ÁLCOOL EM DEPENDENTES QUÍMICOS

DETERMINATION OF PHOSPHATIDYLETANOL IN DRIED BLOOD SPOT BY UHPLC-MS/MS: EVALUATION OF ALCOHOL CONSUMPTION IN CHEMICAL DEPENDENTS. We developed and validated an UHPLC-MS/MS method for the quantification of phosphatidylethanol (PEth) in dried blood spots (DBS). Sample preparation was a liquid extraction and chromatographic separation was performed in an Acquity C8 column. The mobile phases were 4 mM ammonium acetate in water (A) and acetonitrile (B) at 24:76 (v/v). The total analytical run time was 6 minutes, with retention time of 3.36 min for PEth and 4.13 min for phosphatidylpropanol. The method was linear from 10 to 3000 ng mL-1, specific, with, precise and accurate. The analyte was stable in DBS stored from -20 to 45 °C for 21 days. Matrix effect was compensated with the internal standard (-5.21% to + 6.09%). The method was applied in the evaluation of alcohol consumption in DBS from 25 chemical dependents. The PEth concentrations ranged from 14.5 to 2380.8 ng mL-1, with significant correlation with the self-report alcohol consumption AUDIT scores (r=0.41).

Long-term monitoring of drug consumption patterns during the COVID-19 pandemic in a small-sized community in Brazil through wastewater-based epidemiology

The abuse of legal and illegal drugs is a global public health problem, also affecting the social and economic well-being of the population. Thus, there is a significant interest in monitoring drug consumption. Relevant epidemiological information on lifestyle habits can be obtained from the chemical analysis of urban wastewater. In this work, passive sampling using polar organic chemical integrative samplers (POCIS) was used to quantify licit and illicit drugs biomarkers in wastewater for the application of wastewater-based epidemiology (WBE). In this WBE study, a small urban community of approximately 1179 inhabitants was monitored from 18 March 2020 to 3 March 2021, covering the mobility restriction and flexibilization periods of the COVID-19 pandemic in Brazil. Consumption was estimated for amphetamine, caffeine, cocaine, MDMA, methamphetamine, nicotine, and THC. The highest estimated consumption among illicit drugs was for THC (2369 ± 1037 mg day^-1 1000 inh^-1) followed by cocaine (353 ± 192 mg day^-1 1000 inh^-1). There was a negative correlation between consumption of caffeine, cocaine, MDMA, nicotine, and THC with human mobility, expressed by cellular phone mobility reports (P-value = 0.0094, 0.0019, 0.0080, 0.0009, and 0.0133, respectively). Our study is the first long-term drug consumption evaluation during the COVID-19 pandemic, with continuous sampling for almost a whole year. The observed reduction in consumption of both licit and illicit drugs is probably associated with stay-at-home orders and reduced access, which can be due to the closure of commercial facilities during some time of the evaluated period, smaller drug supply, and reduced income of the population due to the shutdown of companies and unemployment. The assay described in this study can be used as a complementary and cost-effective tool to the long-term monitoring of drug use biomarkers in wastewater, a relevant epidemiological strategy currently limited to short collection times.

Evaluation of the Tasso-SST® capillary blood microsampling device for the measurement of endogenous uracil levels

BACKGROUND

Uracil (U) plasma or serum levels can be used as surrogates of dihydropyrimidine dehydrogenase (DPD) activity, which is strongly related to the occurrence of severe or fatal toxicity after administration of fluoropyrimidines (FP) chemotherapy. Obtaining blood plasma or serum for U measurement usually requires a phlebotomy procedure by a qualified professional. An alternative to conventional blood drawn is the use of the Tasso-SST® device, which allows the collection of a small blood volume from skin capillaries. This study aimed to implement a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the determination of U in small serum samples and to compare U concentrations measured in venous plasma, obtained after phlebotomy, and serum obtained with the Tasso-SST® device.

METHODS

Fifty microliter samples were prepared through simple protein precipitation with trichloroacetic acid. Chromatographic separation was performed with a porous graphitic carbon stationary phase and mass spectrometric detection used positive electrospray ionization. The assay was validated according to international guidelines.

RESULTS

The linear range of the assay was 5-250 ng/mL. Measurement accuracy was in the range of 98.8-108.2%, inter-assay precision was 4.3-7.3%, and intra-assay precision was 3.4-6.1%. The average matrix effect was -6.42%. The extraction yield was 95-103.3%. U concentrations measured in serum obtained with the Tasso-SST® device and venous blood plasma were highly correlated (rs = 0.910, P < 0.0001), and no systematic or proportional bias between U levels measured in both matrices was found.

CONCLUSIONS

The use of blood microsampling with the Tasso-SST® device is a useful alternative for the measurement of U and the identification of patients with DPD deficiency.

Potential use of distinct biomarkers (trace metals, micronuclei, and nuclear abnormalities) in a heterogeneous sample of birds in southern Brazil

The analysis of metal concentrations in bird feathers and genotoxicity tests are tools used to evaluate anthropogenic impacts on ecosystems. We investigated the response of birds, used as bioindicators, to disturbances observed in three areas with distinctive environmental characteristics (natural, agricultural, and urban) in southern Brazil. For this purpose, we quantified metals (Mn, Cu, Cr, and Zn) in feathers and determined the number of micronuclei (MN) and other nuclear abnormalities (NA) in 108 birds from 25 species and 17 families captured in the study area. No significant differences was found in the metal concentrations and the number of MN and NA between the sampling areas. Zn and Cu concentrations were significantly higher in insectivorous than those in omnivorous birds. The Zn concentration was significantly different between some species, and the Cu concentration was significantly higher in juveniles than that in adults. The best generalized linear models showed that omnivorous birds had more MN and NA and that juveniles and birds with better body condition index had increased NA numbers. This study demonstrates that the analyzed variables contribute in different ways to the result of each biomarker, mainly due to particular ecological and physiological characteristics of each species. We conclude that wild birds have the potential to be used as environmental bioindicators in the study area, but future studies should focus on one or a few species whose ecological and physiological habits are well known.

Neuroprotective Gene Therapy by Overexpression of the Transcription Factor MAX in Rat Models of Glaucomatous Neurodegeneration

Purpose

Based on our preview evidence that reduced nuclear content of the transcription factor Myc-associated protein X (MAX) is an early event associated with degeneration of retinal ganglion cells (RGCs), in the present study, our purpose was to test whether the overexpression of human MAX had a neuroprotective effect against RGC injury.

Methods

Overexpression of either MAX or green fluorescent protein (GFP) in the retina was achieved by intravitreal injections of recombinant adenovirus-associated viruses (rAAVs). Lister Hooded rats were used in three models of RGC degeneration: (1) cultures of retinal explants for 30 hours ex vivo from the eyes of 14-day-old rats that had received intravitreal injections of rAAV2-MAX or the control vector rAAV2-GFP at birth; (2) an optic nerve crush model, in which 1-month-old rats received intravitreal injection of either rAAV2-MAX or rAAV2-GFP and, 4 weeks later, were operated on; and (3) an ocular hypertension (OHT) glaucoma model, in which 1-month-old rats received intravitreal injection of either rAAV2-MAX or rAAV2-GFP and, 4 weeks later, were subject to cauterization of the limbal plexus. Cell death was estimated by detection of pyknotic nuclei and TUNEL technique and correlated with MAX immunocontent in an ex vivo model of retinal explants. MAX expression was detected by quantitative RT-PCR. In the OHT model, survival of RGCs was quantified by retrograde labeling with DiI or immunostaining for BRN3a at 14 days after in vivo injury. Functional integrity of RGCs was analyzed through pattern electroretinography, and damage to the optic nerve was examined in semithin sections.

Results

In all three models of RGC insult, gene therapy by overexpression of MAX prevented RGC death. Also, ON degeneration and electrophysiologic deficits were prevented in the OHT model.

Conclusions

Our experiments offer proof of concept for a novel neuroprotective gene therapy for glaucomatous neurodegeneration based on overexpression of MAX.

Development and validation of an assay for the measurement of gentamicin concentrations in dried blood spots using UHPLC-MS/MS

Gentamicin sulfate (GEN) is an aminoglycoside antibiotic with a narrow therapeutic range of plasma concentrations. The collection of venous blood represents a significant burden for patients, especially in neonatology. Dried blood spots (DBS) obtained from capillary blood can be an alternative for drug measurements in this particular population. This study aimed to develop and validate an assay for the quantification of GEN in DBS using UHPLC-MS/MS. Total GEN concentrations were obtained by adding the individual concentrations of the GEN forms C1, C1a, and C2. The assay used a DBS disk containing approximately 17 μL of blood for GEN quantitation in the range of 0.1-40 mg L^-1. Measurement accuracy for total GEN was in the range of 102.6-108.6%, inter-assay precision was 11.3-13.1% and intra-assay precision was 9.1-12.8.% GEN was stable for 21 days at - 20 and 8 °C, but only for 24 h at room temperature. Blood Hct affected the accuracy within acceptable limits (93.8-95% at Hct% of 30, 104.3-113% at Hct% of 50). Blood spotted volume did not affect GEN measurement accuracy. Concentrations of GEN in DBS obtained after heel pricks were correlated to plasma levels in a small cohort of neonatal patients. However, percentual differences between estimated plasma concentrations and actual plasma levels presented values between - 64-35.3% (average difference of - 1.9%). The use of DBS for the measurement of GEN concentrations can increase access to TDM of this antibiotic due to the ease of sample collection and the facilitated specimen transportation logistics when testing is not available onsite.

Determination of clozapine and norclozapine in dried plasma spot and dried blood spot by liquid chromatography-tandem mass spectrometry

The use of alternative blood sampling strategies in clozapine (CLZ) therapeutic drug monitoring (TDM) aims to facilitate collection and improve drug therapy and adherence. This study aimed to develop and validate two methods for the determination CLZ and norclozapine (NOR) in dried blood spots (DBS) and dried plasma spots (DPS) by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The analytes were extracted from one 10 microliter volumetric DBS disc punch and from one 6 mm DPS disc punch with methyl tert-butyl ether: methanol (1:9, v/v) and injected into the HPLC-MS/MS with Atmospheric pressure chemical ionization (APCI) source. Separation was performed in a phenyl column, with mobile phase ammonium formate 1 mM pH 4.0 with methanol in gradient mode. The method was linear from 50 to 1500 ng/ml (r > 0.99), with accuracy between 98% and 105% in DBS and 91-101% in DPS, and intra- and inter-assay CV% from 5.23% to 9.35% in DBS and 2.22-11.36% in DPS for both analytes. The matrix effect was compensated by the internal standard, between - 5.1-6.89% in DBS and - 2.45-5.74% in DPS. The average extraction efficiency was 63-67% for CLZ and 58-69% for NOR with no significant impact of hematocrit (HCT). The analytes were stable in the dried matrices stored up to 42 °C for 26 days. The method was applied in the evaluation of clozapine therapy in 13 schizophrenic patients with mean serum levels of 401 ng/ml (43-914 ng/ml). Only 38% were within the therapeutic range, 46% below and 23% above. CLZ and NOR concentrations in dried samples were highly correlated to serum levels, with greater accuracy for DPS compared to DBS (97 versus 89%, and 99 versus 131%, for CLZ and NOR, respectively). Our data support the use of DBS and DPS as alternative sampling strategies in CLZ therapeutic drug monitoring, with satisfactory performance and logistics advantages.

DETERMINAÇÃO DE ETIL-GLICURONÍDEO E ETIL-SULFATO EM SANGUE POR UPLC-MS/MS: APLICAÇÃO CLÍNICA EM VÍTIMAS DE TRAUMA

DETERMINATION OF ETHYL-GLUCURONIDE AND ETHYL-SULFATE IN BLOOD BY UPLC-MS/MS: CLINICAL APPLICATION IN TRAUMA VICTIMS. We developed a UPLC-MS/MS method for the quantification of the ethanol metabolites ethyl-glucuronide (EtG) and ethyl-sulfate (EtS) in blood samples. Sample preparation was a protein precipitation with acetonitrile 0.1% formic acid containing internal standards (IS) 0.5 µg mL-1 EtG-D5 and EtS-D5. Chromatographic separation was performed in a fluoro-phenyl column, mobile phases were 0.1% formic acid in water (A) and acetonitrile (B) in gradient elution from 5% B to 70% B, with 10 min run time. Ionization was performed with electrospray source at 550 °C in negative mode, quantification mass transitions of m/z EtG 221- 75, EtS 125- 80.1, EtS-D5 130- 79.9, and EtG-D5 226- 75.1. The method was linear from 0.1 to 18 µg mL-1 for EtG and 0.02 to 6 µg mL-1 for EtS, specific, with no interfering peaks during the blank samples analyses. The method was precise and accurate, the matrix effect was compensated with the IS (-12% a + 6.1%). EtG and EtS were analyzed in 28 blood samples from trauma patients with positive alcoholaemia. The concentrations of EtG and EtS ranged from 0.25 to 14.11 µg mL-1 and 0.13 to 5.53 µg mL-1, with high correlation with ethanol concentrations, r=0.739 and r=0.817 (p <0,001), respectively

Sensitive determination of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol and complementary cannabinoids in hair using alkaline digestion and mixed-mode solid phase extraction followed by liquid-chromatography-tandem mass spectrometry

Hair drug testing can be used for the evaluation of cannabis use with a large detection window, and is required for professional driving license granting in Brazil. A positive hair result for cannabis use requires quantification of the metabolite THC-COOH above the cutoff value of 0.2 ng/g. The achievement of such lower limit of quantification is challenging, particularly with the use of liquid chromatography coupled to triple quadrupole mass spectrometers (LC-MS/MS). In this study, a very sensitive LCMS/ MS assay for the simultaneous quantification of THC-COOH along with THC, CBD, and CBN was developed and validated. Sample preparation was based on hair hydrolysis, followed by selective ion-exchange solid-phase extraction. The extraction yield was 101.5-101.6% for THC-COOH, 92.3-97.4% for THC, 89.7-95.2% for CBN, and 104.9-121.1% for CBD. Internal standard corrected matrix effects were - 2.7 to - 1,1 for THCCOOH and - 11.5 to - 0.1% for the other analytes. The lower limit of quantification was 01 ng/g for THC-COOH and 25 ng/g for THC, CBD, and CBN. The assay fulfilled validation guidelines acceptance criteria. The measurement uncertainties were determined and the assay was ISO17025 accredited, being currently used in routine testing.

Sensitive determination of gentamicin in plasma using ion-exchange solid-phase extraction followed by UHPLC-MS/MS analysis

Background

Therapeutic drug monitoring (TDM) of gentamicin sulfate (GEN) is usually recommended, particularly in critical patients. Only a few reports had described the determination of GEN in plasma or plasma using LC-MS/MS.

Objective

This study aimed to develop and validate a sensitive ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) assay for the quantification of GEN in small volumes of human plasma.

Results

The use of a very low concentration of the ion-pairing agent HFBA allowed significant retention of the very polar GEN forms in a reversed phase UHPLC column. The solid-phase extraction (SPE) procedure allowed clean extracts, with no interferences detected in blank samples, and high sensitivity. The assay was linear on the range of 0.2–40 mg L⁻¹ of GEN complex. The combined GEN complex had inter-assay CV of 8.8–10.0%, intra-assay CV of 10.2–11.0%, and accuracy of 96.8–104.0%. The assay was applied to 17 clinical samples obtained from neonate patients. Measured concentrations were in the range of 0.15–3.57 mg L⁻¹ for GEN C1, 0.12–3.55 mg L⁻¹ for GEN C1a, 0.20–5.77 mg L⁻¹ for GEN C2, and 0.47–12.88 mg L⁻¹ for the GEN complex, all within the linear range of the assay.

Conclusion

A sensitive assay for the quantification of gentamicin in plasma using anion-exchange SPE and UHPLC-MS/MS was validated. The assay can be used for TDM of gentamicin, particularly in centers with access to proper instrumentation and with a low demand for gentamicin measurements, where immunoassays are not cost-effective.

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Gentamicin was extracted from plasma using ion-exchange solid phase extraction.

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Chromatographic conditions were previously applied for amikacin and vancomycin.

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Gentamicin was measured with acceptable accuracy and precision using UHPLC-MS/MS.

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The assay was sensitive and had a linear range covering clinically relevant concentrations.

Dried Plasma Spots and Oral Fluid as Alternative Matrices for Therapeutic Drug Monitoring of Busulfan: Analytical Method Development and Clinical Evaluation

BACKGROUND

Busulfan (BU) is an alkylating agent with a narrow therapeutic index and high intraindividual pharmacokinetic variability used in conditioning therapy for hematopoietic stem cell transplantation. Monitoring BU exposure during high-dose conditioning regimens is recommended and positively impacts outcomes. We aimed to develop, validate, and apply a ultra-high-performance liquid chromatography-mass spectrometry (MS)/MS assay to measure BU concentrations in oral fluid and dried plasma spots (DPS) as alternative matrices to plasma.

METHODS

We prepared plasma and oral fluid samples by protein precipitation and DPS after liquid extraction. We analyzed extracts using an LC-MS/MS system with an Acquity HSS T3 column in the positive electrospray ionization mode. The method was validated and applied to 79 paired plasma and oral fluid samples from 7 patients on BU conditioning treatment. DPS were prepared by pipetting plasma onto Whatman 903 paper. The correlation between BU in plasma, oral fluid, and DPS samples was evaluated.

RESULTS

Run time was 4.0 minutes. The assay was linear at 50-5000 ng mL-1 (r > 0.99), precise (1.9%-5.3% oral fluid and 1.8%-5.9% DPS), and accurate (98.1%-108.9% oral fluid and 93%-103.1% DPS). BU was stable in DPS at 23°C for 24 hours. BU levels in oral fluid (r = 0.927) and DPS (r = 0.982) were significantly correlated with plasma. Despite the good correlation, we found a wide variation between oral fluid and plasma levels. The area under curves (AUCs) calculated with oral fluid concentrations were 79.1%-167.1% of plasma AUCs. Bland-Altman plots found a better agreement for DPS, with AUCs estimated from corrected DPS levels at 83.1%-114.1% of plasma values.

CONCLUSIONS

We developed and validated a simple and fast ultra-high-performance liquid chromatography-MS/MS assay to measure BU in oral fluid and DPS. The results do not support the use of oral fluid as a matrix for routine therapeutic drug monitoring of BU. The AUC estimated from BU measurements in DPS was comparable to that in plasma, supporting the use of DPS in BU therapeutic drug monitoring as an alternative matrix, with adequate short-term stability and logistic advantages.

Alternative Sampling Devices to Collect Dried Blood Microsamples: State-of-the-Art

ABSTRACT

Dried blood spots (DBS) have been used in newborn screening programs for several years. More recently, there has been growing interest in using DBS as a home sampling tool for the quantitative determination of analytes. However, this presents challenges, mainly because of the well-known hematocrit effect and other DBS-specific parameters, including spotted volume and punch site, which could add to the method uncertainty. Therefore, new microsampling devices that quantitatively collect capillary dried blood are continuously being developed. In this review, we provided an overview of devices that are commercially available or under development that allow the quantitative (volumetric) collection of dried blood (-based) microsamples and are meant to be used for home or remote sampling. Considering the field of therapeutic drug monitoring (TDM), we examined different aspects that are important for a device to be implemented in clinical practice, including ease of patient use, technical performance, and ease of integration in the workflow of a clinical laboratory. Costs related to microsampling devices are briefly discussed, because this additionally plays an important role in the decision-making process. Although the added value of home sampling for TDM and the willingness of patients to perform home sampling have been demonstrated in some studies, real clinical implementation is progressing at a slower pace. More extensive evaluation of these newly developed devices, not only analytically but also clinically, is needed to demonstrate their real-life applicability, which is a prerequisite for their use in the field of TDM.

Dissociation of genotype-dependent cognitive and motor behavior in a strain of aging mice devoid of the prion protein

The prion glycoprotein (PrP^C) is highly expressed in the nervous system as well as in other organs. Its functional roles in behavior have been examined mainly in non co-isogenic, wild-type and PrP^C-deficient mice, which showed both age- and genotype-dependent differences. In general, however, effects of genetic background upon behavioral tests are mostly unclear when applied to aging rodents. The present study aimed to determine the effect of deletion of the prion protein on behavior of isogenic mice across different ages. We disclosed a genotype-dependent behavioral dissociation between either motor or cognitive tests, as a function of both age and test type. Remarkably, we also detected a clear age- and genotype-dependent difference in the variability of performance in a cognitive test. The current findings are relevant for both the interpretation of PrP^C-related behavior, as well as for issues of reproducibility in studies of rodent behavior.

Simple extraction of toxicologically relevant psychotropic compounds and metabolites from whole blood using mini-QuEChERS followed by UPLC-MS/MS analysis

The determination of psychotropic drugs and metabolites in blood is relevant in the context of both therapeutic drug monitoring and clinical and forensic toxicology. LC-MS/MS is the preferred method for these assays. However, LC-MS/MS is particularly susceptible to matrix ionization effects and appropriate sample preparation is required to minimize these effects. In this study, a simple, single-step, mini-QuEchERS extraction procedure, coupled to UPLC-MS/MS, was developed and validated for the determination of 15 toxicologically relevant compounds in whole blood, including psychoactive drugs and some metabolites. The assay was linear in the range of 25-1,000 ng ml^-1 , fulfilling criteria for accuracy and precision. Extraction yields (71.9-87.7%) and matrix effects (-3.3 to +4.4%, with the exception of codeine, which had matrix effects of -35.36 to -28.14%) were acceptable for the majority of the evaluated compounds, using a single internal standard. The assay was applied to 238 clinical specimens from patients admitted to an emergency service, with 22 samples presenting quantifiable concentrations of 11 different compounds. The developed assay is a simple and efficient strategy for determination of target psychotropic drugs and metabolites in forensic and clinical toxicology.

Evaluation of Illicit Drug Consumption by Wastewater Analysis Using Polar Organic Chemical Integrative Sampler as a Monitoring Tool

Illicit drug abuse is a worldwide social and health problem, and monitoring illicit drug use is of paramount importance in the context of public policies. It is already known that relevant epidemiologic information can be obtained from the analysis of urban residual waters. This approach, named wastewater-based epidemiology (WBE), is based on the measurement of specific markers, resulting from human biotransformation of the target drugs, as indicators of the consumption of the compounds by the population served by the wastewater treatment installation under investigation. Drug consumption estimation based on WBE requires sewage sampling strategies that express the concentrations along the whole time period of time. To this end, the most common approach is the use of automatic composite samplers. However, this active sampling procedure is costly, especially for long-term studies and in limited-resources settings. An alternative, cost-effective, sampling strategy is the use of passive samplers, like the polar organic chemical integrative sampler (POCIS). POCIS sampling has already been applied to the estimation of exposure to pharmaceuticals, pesticides, and some drugs of abuse, and some studies evaluated the comparative performances of POCIS and automatic composite samplers. In this context, this manuscript aims to review the most important biomarkers of drugs of abuse consumption in wastewater, the fundamentals of POCIS sampling in WBE, the previous application of POCIS for WBE of drugs of abuse, and to discuss the advantages and disadvantages of POCIS sampling, in comparison with other strategies used in WBE. POCIS sampling is an effective strategy to obtain a representative overview of biomarker concentrations in sewage over time, with a small number of analyzed samples, increased detection limits, with lower costs than active sampling. Just a few studies applied POCIS sampling for WBE of drugs of abuse, but the available data support the use of POCIS as a valuable tool for the long-term monitoring of the consumption of certain drugs within a defined population, particularly in limited-resources settings.

Simple determination of valproic acid serum concentrations using BioSPME followed by gas chromatography-mass spectrometric analysis

Valproic acid (VA) is a drug widely used on the treatment of epilepsy and bipolar affective disorders, with stablished therapeutic concentration ranges in serum. The measurement of VA serum concentrations using chromatographic methods requires a sample preparation step. In this context, this study aims to describe the development and validation of an assay for VA measurement in serum using a new microextraction strategy, known as BioSPME, followed by GC-MS analysis. The extraction procedure was very simple based on direct immersion of the BioSPME tips on acidified serum, followed by agitation and desorption in methanol. The methanolic extracts were directly injected into the chromatograph. Extraction yield was 95.6 to 101.3%. The assay was linear from 10 to 150 mg L^-1. Precision, accuracy and stability assays were acceptable according to bioanalytical validation guidelines. The method was applied to 41 clinical serum samples also tested with a previously GC-MS validated assay, which used liquid-liquid extraction as sample preparation. Measurements obtained with both methods were comparable. This study is the first description of the use of BioSPME tips for a therapeutic drug. BioSPME is a promising alternative for the preparation of biological specimens prior to the determination of therapeutic drugs by GC-MS.

Cell proliferation in the central nervous system of an adult semiterrestrial crab

Neurogenesis occurs in adults of most organisms, both vertebrates and invertebrates. In semiterrestrial crabs of the infraorder Brachyura, the deutocerebrum, where neurogenesis occurs, processes the olfactory sensory information from the antennae. The deutocerebrum is composed of a pair of olfactory lobes associated with cell clusters 9 and 10 (Cl 9 and Cl 10), containing proliferating cells. Because the location of the neurogenic niche in brachyuran semiterrestrial crabs has not been defined, here we describe a neurogenic niche in the central olfactory system of the crab Ucides cordatus and report two types of glial cells in the deutocerebrum, based on different markers. Serotonin (5-hydroxytryptamine) labeling was used to reveal neuroanatomical aspects of the central olfactory system and the neurogenic niche. The results showed a zone of proliferating neural cells within Cl 10, which also contains III beta-tubulin (Tuj1)+ immature neurons, associated with a structure that has characteristics of the neurogenic niche. For the first time, using two glial markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), we identified two types of astrocyte-like cells in different regions of the deutocerebrum. This study adds to the understanding of neurogenesis in a brachyuran semiterrestrial crustacean and encourages comparative studies between crustaceans and vertebrates, including mammals, based on shared aspects of both mechanisms of neurogenesis and regenerative potentials.

Gene Therapy Strategies for Glaucomatous Neurodegeneration

Glaucoma leads to irreversible vision loss and current therapeutic strategies are often insufficient to prevent the progression of the disease and consequent blindness. Elevated intraocular pressure is an important risk factor, but not required for the progression of glaucomatous neurodegeneration. The demise of retinal ganglion cells represents the final common pathway of glaucomatous vision loss. Still, lifelong control of intraocular pressure is the only current treatment to prevent severe vision loss, although it frequently fails despite best practices. This scenario calls for the development of neuroprotective and pro-regenerative therapies targeting the retinal ganglion cells as well as the optic nerve. Several experimental studies have shown the potential of gene modulation as a tool for neuroprotection and regeneration. In this context, gene therapy represents an attractive approach as persistent treatment for glaucoma. Viral vectors engineered to promote overexpression of a broad range of cellular factors have been shown to protect retinal ganglion cells and/or promote axonal regeneration in experimental models. Here, we review the mechanisms involved in glaucomatous neurodegeneration and regeneration in the central nervous system. Then, we point out current limitations of gene therapy platforms and review a myriad of studies that use viral vectors to manipulate genes in retinal ganglion cells, as a strategy to promote neuroprotection and regeneration. Finally, we address the potential of combining neuroprotective and regenerative gene therapies as an approach to glaucomatous neurodegeneration.

Evaluation of dried blood spots as an alternative matrix for therapeutic drug monitoring of abiraterone and delta(4)-abiraterone in prostate cancer patients

Therapeutic drug monitoring (TDM) approaches may benefit patients treated with abiraterone acetate (AA) as drug efficacy is imprecise and important pharmacokinetic variability is known. Current methods based on the analysis of plasma present the disadvantage of the fast degradation of the analytes in the liquid sample. Dried blood spots (DBS) consist of a minimally invasive and unexplored sampling strategy to monitor the levels of abiraterone (ABI) and delta(4)-abiraterone (D4A) in patients. This study presents the development and validation of a precise and accurate method to monitor ABI and D4A in DBS samples by UPLC-MS/MS. Bioanalytical method validation was carried out according to current guidelines, evaluating the impact of DBS-specific parameters such as hematocrit and spot volume on accuracy. Based on the analysis of quality control samples prepared at low, medium and high concentrations, the method was precise with CV ≤ 6.97 % and 10.26 % for ABI and D4A, respectively. The method was also highly accurate, between 93.6-106.8 % for ABI and 96.0-108.5 % for D4A. The DBS method is compatible with the analysis of samples of unknown volume and hematocrit range of the studied population. In addition, ABI and D4A were stable for 7 days in DBS at room temperature, which is feasible for sample transportation in postal service and analysis in the laboratory. Method application to 16 clinical samples revealed good correlation between measured plasma concentrations and estimated plasma concentrations for ABI (r = 0.884, P < 0.05) and D4A (r = 0.920, P < 0.05). Passing-Bablok regression analysis and Bland-Altmann plots indicated correlation between the results obtained from DBS and plasma, with a slight overestimation of the concentrations of ABI in DBS, which could be related to the small study cohort. Therefore, the results of this first work indicate that DBS consist of a promising alternative sampling strategy in TDM studies of AA.

Blood phosphatidyl ethanol levels as a tool to detect alcohol misuse in trauma patients

INTRODUCTION

There is a strong need for a reliable marker of harmful alcohol consumption to identify injured patients that can benefit from alcohol interventions, and blood phosphatidyl ethanol (PEth) has not previously been tested on this population. This study aims to compare the performance of blood PEth concentration, blood alcohol concentration (BAC) and the Alcohol Use Disorders Identification Test Consumption (AUDIT-C) for the screening of alcohol misuse in trauma patients.

METHODS

Prospective cross-sectional study of 238 adult patients presenting in the emergency department with any type of trauma. PEth concentration was determined in whole blood by high-performance liquid chromatography with tandem mass spectrometry. Consent, AUDIT-C score and demographic data were obtained.

RESULTS

The sample consisted of majority male (67.6%), single (46.2%) and employed (66%) patients. The most common type of trauma was traffic collision (63.9%). The mean age was 41.7 years. We found a significant correlation between PEth levels with AUDIT-C score (Spearman's r = 0.654; p < .0001). PEth had an area under the ROC curve of 0.885 to detect hazardous alcohol consumption (AUDIT-C score ≥ 6) and PEth ≥23.9 ng/mL cutoff point provided 91.2% of sensitivity and 78.4% of specificity. Twelve patients reported alcohol abstinence, but had quantifiable levels of PEth.

CONCLUSIONS

PEth levels and AUDIT-C score had a moderate correlation in our population. PEth was useful to identify 12 cases of underreporting of alcohol consumption habits. PEth shows promising results, but more research is needed to identify the best screening tool for alcohol misuse in trauma patients.

Seasonal variation of vitamin D among healthy adult men in a subtropical region

SUMMARY OBJECTIVE: To evaluate seasonal variation of 25(OH)vitamin D [25(OH)D3] levels, and factors associated with it, in healthy adult men, who exercised outdoors for 50 min., at least twice a week, from 10AM to 4PM, in a Brazilian semitropical region. METHODS: Blood samples were collected at the end of each season for 25(OH)D3, measured by liquid chromatography with tandem mass spectrometry. Ultraviolet irradiation was estimated by radiometer, calculating the daily photobiological response to vitamin D synthesis in human skin (D-VitD). The prevalence of 25(OH)D3 <20ng/mL changed with the seasons (p=0.000): 8.7% (n=6/69), 1.5% (n=1/66), 0 (n=0/64), and 21.7% (n=13/60), respectively, at the end of winter, spring, summer, and autumn. The prevalence, adjusted for multiple comparisons, was higher in winter than summer (p=0.026), and in autumn than spring (p=0.001) and summer (p=0.000). There were no associations of 25(OH) D3 levels with BMI (p=0.207), body fat (p=0.064), and phototype (p=0.485), in univariate analysis. It was associated with D-VitD in the 30 days before blood sampling (p=0.000), after adjustment to body fat. The prevalence of 25(OH)D3 <30ng/mL varied seasonally (p=0.000): 69.6% (n=48/69), 68.2% (n=45/66), 43.8% (n=28/64), and 88.4% (n=53/60), respectively, in winter, spring, summer, and autumn. CONCLUSIONS: In a Brazilian subtropical region, a seasonal variation in 25(OH)D3 was observed in healthy adult males, although they spent at least 50 min outdoors twice a week, wearing shorts and T-shirts. 25(OH)D3 <20ng/mL was 21.7% in autumn; D-vitD 30 days prior to blood sampling was the only factor independently associated with 25(OH)D3 levels.