Publications by authors named "Regina V Oliveira"

Concerns about the SARS-CoV-2 outbreak (COVID-19) continue to persist even years later, with the emergence of new variants and the risk of disease severity. Common clinical symptoms, like cough, fever, and respiratory symptoms, characterize the noncritical patients, classifying them from mild to moderate. In a more severe and complex scenario, the virus infection can affect vital organs, resulting, for instance, in pneumonia and impaired kidney and heart function.

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Inspiratory muscle training (IMT) is known to promote physiological benefits and improve physical performance in endurance sports activities. However, the metabolic adaptations promoted by different IMT prescribing strategies remain unclear. In this work, a longitudinal, randomized, double-blind, sham-controlled, parallel trial was performed to investigate the effects of 11 weeks (3 days·week) of IMT at different exercise intensities on the serum metabolomics profile and its main regulated metabolic pathways.

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Aging process is characterized by a progressive decline of several organic, physiological, and metabolic functions whose precise mechanism remains unclear. Metabolomics allows the identification of several metabolites and may contribute to clarifying the aging-regulated metabolic pathways. We aimed to investigate aging-related serum metabolic changes using a metabolomics approach.

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Article Synopsis
  • Sickle cell disease (SCD) often leads to vaso-occlusive crises, which can result in severe organ damage including osteonecrosis (ON), affecting up to 50% of SCD patients.
  • A study used NMR-based untargeted metabolomics to analyze blood plasma and bone marrow interstitial fluid from SCD patients with osteonecrosis, identifying metabolic changes linked to different disease stages.
  • Citrate may serve as a potential biomarker to distinguish SCD patients with and without osteonecrosis, while metabolites like acetate, creatinine, and glucose were associated with various disease stages; however, the study's findings are limited by small sample sizes and lack of validation.
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Reduced nicotinamide adenine dinucleotide phosphate (NADPH) participates in several anabolic and catabolic pathways, being essential in numerous biochemical reactions involving energy release. Most of these reactions require a high amount of NADPH, which can be expensive from an industry point of view. Thus, biotechnology industries developed a great interest in NADPH production.

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The extensive use of medicinal herbs to traditionally treat disease persists for generations, and scientific evidence on plant-derived extracts has indicated their numerous biological activities. The , popular known as cow's paw ("pata de vaca"), with more than 60 native species, are extensively used in Brazilian popular medicine for the control of diabetes. Therefore, in 2009, , and/or were included in the Brazilian National List of Medicinal Plants of Interest to SUS (RENISUS - Brazil).

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Cardiovascular diseases (CVDs) are noncommunicable diseases known for their complex etiology and high mortality rate. Oxidative stress (OS), a condition in which the release of free radical exceeds endogenous antioxidant capacity, is pivotal in CVC, such as myocardial infarction, ischemia/reperfusion, and heart failure. Due to the lack of information about the implications of OS on cardiovascular conditions, several methodologies have been applied to investigate the causes and consequences, and to find new ways of diagnosis and treatment as well.

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Metabolomics is a discipline that offers a comprehensive analysis of metabolites in biological samples. In the last decades, the notable evolution in liquid chromatography and mass spectrometry technologies has driven an exponential progress in LC-MS-based metabolomics. Targeted and untargeted metabolomics strategies are important tools in health and medical science, especially in the study of disease-related biomarkers, drug discovery and development, toxicology, diet, physical exercise, and precision medicine.

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Metabolomics and lipidomics have demonstrated increasing importance in underlying biochemical mechanisms involved in the pathogenesis of diseases to identify novel drug targets and/or biomarkers for establishing therapeutic approaches for human health. Particularly, bioactive metabolites and lipids have biological activity and have been implicated in various biological processes in physiological conditions. Thus, comprehensive metabolites, and lipids profiling are required to obtain further advances in understanding pathophysiological changes that occur in cells and tissues.

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In recent decades, fungi-derived naturally occurring quinazolines have emerged as potential drug candidates. Nevertheless, most studies are conducted for bioactivity assays, and little is known about their absorption, distribution, metabolism, and elimination (ADME) properties. To perform metabolic studies, the synthesis of the naturally occurring quinazolinone, fiscalin B (), and its chloro derivative, 4-((1-indol-3-yl)methyl)-8,10-dichloro-1-isobutyl-1,2-dihydro-6-pyrazino[2,1-]quinazoline-3,6(4)-dione (), disclosed as an antibacterial agent, was performed in a gram scale using a microwave-assisted polycondensation reaction with 22% and 17% yields, respectively.

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Forced degradation tests are studies used to assess the stability of active pharmaceutical ingredients (APIs) and their formulations. These tests are performed submitting the API under extreme conditions in order to know the main degradation products in a short period of time. The results of these studies are used to assess the degradation susceptibility of APIs and to validate chromatographic analytical methods.

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Sickle cell anaemia (SCA) is a debilitating genetic haemoglobinopathy predominantly affecting the disenfranchised strata of society in Africa and the Americas. The most common pharmacological treatment for this disease is the administration of hydroxycarbamide (HC) for which questions remain regarding its mechanism of action, efficacy and long-term toxicity specifically in paediatric individuals. A multiplatform metabolomics approach was used to assess the metabolome of plasma samples from a population of children and adolescents with SCA with and without HC treatment along with non-SCA individuals.

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A potent synthetic α-adrenergic agonist called PT-31, (3-(2-chloro-6-fluorobenzyl)-imidazolidine-2,4-dione), was recently detected as a potential drug to be used as an adjuvant drug to treat chronic pain. The excellent pharmacological property of PT-31 highlights the importance in elucidating its metabolism, which could provide valuable information about its metabolite profile for further pharmacokinetics studies and additionally to estimate the impact of its metabolites on the efficacy, safety and elimination of PT-31. In this work, the study of the in vitro metabolism of PT-31 was initially carried out by using a liquid chromatography coupled to ion trap multiple-stage mass spectrometer (LC-IT-MS) and a hybrid triple quadrupole/linear ion trap mass spectrometer (LC-QTrap).

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This paper reports an online SPE-LC-MS/MS method for the simultaneous quantification of prostaglandins (PGE and PGF) in menstrual fluid samples. To meet this goal human peripheral serum was used as surrogate matrix. The analytes were trapped on an OASIS HLB cartridge for 3 min, for sample cleanup and enrichment, and then transferred during only 42 s to an HSS T3 C18 analytical column, for separation and analysis.

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Perturbation of organic anion transporter (OAT) 1- and OAT3-mediated transport can alter the exposure, efficacy, and safety of drugs. Although there have been reports of the endogenous biomarkers for OAT1/3, none of these have all of the characteristics required for a clinical useful biomarker. Cynomolgus monkeys were treated with intravenous probenecid (PROB) at a dose of 40 mg/kg in this study.

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Azo dyes are known as a group of substances with DNA damage potential that depend on the nature and number of azo groups connected to aromatic rings (benzene and naphthalene), chemical properties, e.g. solubility and reactive functional groups, which significantly affect their toxicological and ecological risks.

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Montelukast has been recommended as a selective in vitro and in vivo probe of cytochrome P450 (P450) CYP2C8 activity, but its selectivity toward this enzyme remains unclear. We performed detailed characterization of montelukast metabolism in vitro using human liver microsomes (HLMs), expressed P450s, and uridine 5'-diphospho-glucuronosyltransferases (UGTs). Kinetic and inhibition experiments performed at therapeutically relevant concentrations reveal that CYP2C8 and CYP2C9 are the principal enzymes responsible for montelukast 36-hydroxylation to 1,2-diol.

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This work presents an in vitro investigation of the effect of protein restriction on the metabolism of albendazole (ABZ). This study was conducted using liver microsomal fractions obtained from Wistar rats. For the quantitative analysis, a multidimensional High Performance Liquid Chromatography (2D HPLC) method was fully validated for the determination of the ABZ metabolites: albendazole sulfoxide, albendazole sulfone and albendazole 2-aminesulfone.

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Rationale: Pharmacokinetic data to support clinical development of pharmaceuticals are routinely obtained from liquid plasma samples. The plasma samples require frozen shipment and storage and are extracted off-line from the liquid chromatography/tandem mass spectrometry (LC/MS/MS) systems. In contrast, the use of dried blood spot (DBS) sampling is an attractive alternative in part due to its benefits in microsampling as well as simpler sample storage and transport.

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Background: Online automated extraction of dried blood spots (DBS) via direct extraction to a solid-phase extraction (SPE) cartridge and bioanalysis by high-resolution accurate mass spectrometry was examined. The methodology was validated and used to investigate the effect of hematocrit on assay bias using partial and whole spot extractions from accurately dispensed blood samples.

Results: The completed analysis of a DBS sample was accomplished within 2 to 3 min using the online DBS-SPE platform.

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An integrated automated approach has been developed for the direct determination of drug concentrations using a SCAP DBS system for online extraction and analysis of dried blood spots (DBS) from DBS paper cards to a multidimensional liquid chromatography system coupled to a high-resolution QTOF mass spectrometry (LC-HRMS). An accurate, precise, selective, and sensitive two-dimensional liquid chromatography-high-resolution mass spectrometry (2D LC-HRMS) assay was developed and validated using small volumes of rat blood (approximately 1.25 μL) from a 2 mm DBS punch.

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The use of DBS is an appealing approach to employing microsampling techniques for the bioanalysis of samples, as has been demonstrated for the past 50 years in the metabolic screening of metabolites and diseases. In addition to its minimally invasive sample collection procedures and its economical merits, DBS microsampling benefits from the very high sensitivity, selectivity and multianalyte capabilities of LC-MS, which has been especially well demonstrated in newborn screening applications. Only a few microliters of a biological fluid are required for analysis, which also translates to significantly reduced demands on clinical samples from patients or from animals.

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In this work, the development of two multidimensional liquid chromatography methods coupled to a fluorescence detector is described for direct analysis of microsomal fractions obtained from rat livers. The chiral multidimensional method was then applied for the optimization of the in vitro metabolism of albendazole by experimental design. Albendazole was selected as a model drug because of its anthelmintics properties and recent potential for cancer treatment.

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This work evaluated the potential of the isoforms of methamidophos to cause organophosphorus-induced delayed neuropathy (OPIDN) in hens. In addition to inhibition of neuropathy target esterase (NTE) and acetylcholinesterase (AChE), calpain activation, spinal cord lesions and clinical signs were assessed. The isoforms (+)-, (±)- and (-)-methamidophos were administered at 50mg/kg orally; tri-ortho-cresyl phosphate (TOCP) was administered (500mg/kg, po) as positive control for delayed neuropathy.

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Analytical and semipreparative high performance liquid chromatography methods using polysaccharide-based chiral stationary phases were developed for the enantiomeric resolution of albendazol sulfoxide. The enantioseparation of this compound was evaluated with four chiral stationary phases: cellulose and amylose tris(3,5-dimethylphenylcarbamate), amylose tris[(S)-1-phenylethylcarbamate] and amylose tris(3,5-dimethoxyphenylcarbamate), under three elution conditions: normal, reversed-phase and polar organic mode. The influences of the mobile phase and of the structure of the chiral stationary phase on the enantiomeric separation are discussed.

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