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1.
Eur J Endocrinol ; 183(2): 129-139, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32413848

RESUMO

Background: In patients with phaeochromocytomas or paragangliomas (PPGLs), 24-h urine collections for metanephrines (uMNs) are cumbersome. Objective: To evaluate the diagnostic utility of ratios to creatinine of 'spot' uMNs. Methods: Concentrations of uMNs and plasma metanephrines (pMNs) were measured by HPLC-mass-spectrometry. We retrospectively compared correlations of 24-h-urine output and ratio to creatinine in historical specimens and prospectively assessed 24-h and contemporaneous spot urines and, where possible, pMNs. Using trimmed log-transformed values, we derived reference intervals based on age and sex for spot urines. We used multiples of upper limit of normal (ULNs) to compare areas under curves (AUCs) for receiver-operator characteristic curves of individual, and sum and product of, components. Results: In 3143 24-h-urine specimens on 2416 patients, the correlation coefficients between the ratios and outputs of metanephrine, normetanephrine and 3-methoxytyramine in 24-h urines were 0.983, 0.905 and 0.875, respectively. In 96 patients, the correlations between plasma concentrations, urine output and ratios in spot specimens were similar to those for raw output or ratios in 24-h specimens. Of the 160 patients with PPGLs, the CIs for AUCs for individual metabolites overlapped for all four types of measurement, as did those for the sum of the multiple ULNs although these were slightly higher (AUC for spot urine: 0.838 (0.529-1), plasma: 0.929 (0.874-0.984) and output: 0.858 (0.764-0.952)). Conclusions: Ratios of fractionated metanephrines to creatinine in spot urine samples appear to have a similar diagnostic power to other measurements. The ease of spot urine collection may facilitate diagnosis and follow-up of PPGLs through improved patient compliance.


Assuntos
Neoplasias das Glândulas Suprarrenais/urina , Metanefrina/sangue , Metanefrina/urina , Paraganglioma/urina , Feocromocitoma/urina , Adolescente , Neoplasias das Glândulas Suprarrenais/sangue , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Cromatografia Líquida de Alta Pressão , Creatinina/sangue , Creatinina/urina , Dopamina/análogos & derivados , Dopamina/sangue , Dopamina/urina , Feminino , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Normetanefrina/sangue , Normetanefrina/urina , Paraganglioma/sangue , Feocromocitoma/sangue , Curva ROC , Valores de Referência , Estudos Retrospectivos , Fatores Sexuais , Adulto Jovem
2.
Brain Stimul ; 13(1): 105-108, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31494070

RESUMO

BACKGROUND: Recent evidence suggests that transcranial direct current stimulation (tDCS) may interact with the dopaminergic system to affect cognitive flexibility. Objective/hypotheses: We examined whether putative reduction of dopamine levels through the acute phenylalanine/tyrosine depletion (APTD) procedure and excitatory anodal tDCS of the dorsolateral prefrontal cortex (dlPFC) are causally related to cognitive flexibility as measured by task switching and reversal learning. METHOD: A double-blind, sham-controlled, randomised trial was conducted to test the effects of combining anodal tDCS and depletion of catecholaminergic precursor tyrosine on cognitive flexibility. RESULTS: Anodal tDCS and tyrosine depletion had a significant effect on task switching, but not reversal learning. Whilst perseverative errors were significantly improved by anodal tDCS, the APTD impaired reaction times. Importantly, the combination of APTD and anodal tDCS resulted in cognitive performance which did not statistically differ to that of the control condition. CONCLUSIONS: Our results suggest that the effects of tDCS on cognitive flexibility are modulated by dopaminergic tone.


Assuntos
Cognição , Dopamina/deficiência , Córtex Pré-Frontal/fisiologia , Estimulação Transcraniana por Corrente Contínua , Dopamina/sangue , Feminino , Humanos , Masculino , Tempo de Reação , Reversão de Aprendizagem , Tirosina/sangue , Tirosina/deficiência , Adulto Jovem
3.
Anal Chim Acta ; 1094: 80-89, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761050

RESUMO

In this paper, a composite electrode of N,P-doped Mo2C@C/Prussian blue (PB)/graphite felt (N,P-Mo2C@C/PB/GF) was prepared by a simple method and used for sensitive and effective detection of dopamine (DA). N,P-doped Mo2C nanospheres were prepared by using phosphomolybdic acid (PMo12) as an initiator to promote the polymerization of polypyrrole. Such nanospheres were used to accelerate the deposition process of PB from K3[Fe(CN)6] and FeCl3 in solution. The N,P-Mo2C@C/PB nanohybrid was then anchored to GF in order to obtain the electrochemical sensor. Two linear ranges were extrapolated for dopamine detection: from 0.18 to 30 µmol L-1 with a sensitivity of 0.268 µA µmol-1, and from 30 to 280 µmol L-1 with a sensitivity of 0.045 µA µmol-1. The device showed a detection limit as low as 0.011 µmol L-1, an excellent selectivity to DA over common interfering analytes, and a favorable long-time stability. Finally, the sensor was used for quantitative analysis of DA in the 10-fold dilution of human serum (10%) and exhibited a satisfactory recovery.


Assuntos
Carbono/química , Dopamina/sangue , Ferrocianetos/química , Grafite/química , Molibdênio/química , Nanocompostos/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ferrocianetos/síntese química , Humanos , Limite de Detecção , Nitrogênio/química , Fósforo/química , Reprodutibilidade dos Testes
4.
Artigo em Inglês | MEDLINE | ID: mdl-31670057

RESUMO

Catecholamines [dopamine (DA), epinephrine (E), and norepinephrine (NE)] and their metabolites [metanephrine (MN), normetanephrine (NMN), and 3-methoxytyramine (3-MT)] are functionally important in humans. Their overexpression can indicate the presence of neuroendocrine tumors. Accurate and rapid quantitation of catecholamines and their metabolites may function in differential diagnosis of neuroendocrine tumors. Herein, we diluted 200 µL plasma using isotope labelled internal standards (IS), and extracted using solid phase extraction. The performance of isotope diluted liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) was evaluated and applied to quantify the level of catecholamines and metabolites in clinical samples from 73 apparently healthy adults. The total analysis time of the ID-LC-MS/MS method was 4 min. The improved method was highly sensitive, with a limit of quantification (LOQ) for MN, NMN, 3-MT, and E of 1 pg/mL, a LOQ for DA of 5 pg/mL, and for NE of 10 pg/mL. After correction using IS, no significant matrix effects were observed. Good reproducibility was obtained, with total CVs of 3.2-13.1% (DA), 4.8-10.0% (E), 6.2-6.9% (NE), 3.8-7.9% (MN), 4.1-8.8% (NMN), 3.4-8.9% (3-MT). Recoveries were in the range of 91.1-109.7% for the six analytes. Also, the mean concentration of catecholamines were as follows: MN, 22.9 ±â€¯7.2 pg/mL; NMN, 41.4 ±â€¯17.2 pg/mL; 3-MT, 2.34 ±â€¯2.01 pg/mL; DA, 10.2 ±â€¯4.6 pg/mL; E, 29.3 ±â€¯14.2 pg/mL and NE 427.0 ±â€¯190.6 pg/mL. A reliable ID-LC-MS/MS method for the determination of catecholamines and their metabolites using small volumes of plasma was verified. This method is rapid, simple, and may serve as an essential diagnostic tool for neuroendocrine tumors in clinical practice.


Assuntos
Catecolaminas/sangue , Catecolaminas/metabolismo , Dopamina/análogos & derivados , Metanefrina/sangue , Normetanefrina/sangue , Espectrometria de Massas em Tandem/métodos , Adulto , Idoso , Cromatografia Líquida de Alta Pressão/métodos , Dopamina/sangue , Feminino , Humanos , Limite de Detecção , Masculino , Metaboloma , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos
5.
Mikrochim Acta ; 186(12): 746, 2019 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-31691865

RESUMO

Well-dispersed and graft-crosslinked gold nanoparticles (AuNPs) were synthesized by the reduction of tetrachloroaurate with hydrazine at room temperature. The AuNPs possess a high density of surface defects which is due to grafting of n-octanoic acid to polyvinylpyrrolidone. The physical and chemical properties of the resulting AuNPs were characterized by UV-vis, XRD, TEM/HRTEM, SAED, and XPS, respectively. The modified AuNPs were placed on a glassy carbon electrode (GCE) in an electropolymerized taurine layer to obtain a sensitive, selective, stable and rapid electrochemical dopamine sensor. The peak current, typically measured at 0.17 V (vs. SCE), increases linearly in the 1.0 to 120 µM dopamine concentration range, and the limit of detection (at S/N = 3) is 0.16 µM with a sensitivity of 2.94 µA·µM-1·cm-2. The sensor was successfully applied to the determination of dopamine in injections and spiked serum samples. The recoveries from spiked serum samples range from 97.5 to 102.4%, with RSDs ranging between 2.8 and 3.4%. Graphical abstract Schematic representation of a glassy carbon electrode modified with in-situ graft-crosslinked gold nanoparticles combined with an electropolymerized polytaurine membrane. The sensor exhibits excellent features towards dopamine determination.


Assuntos
Dopamina/sangue , Nanopartículas Metálicas/química , Polímeros/química , Caprilatos/química , Carbono/química , Dopamina/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Humanos , Limite de Detecção , Membranas Artificiais , Oxirredução , Polimerização , Polímeros/síntese química , Povidona/química , Reprodutibilidade dos Testes , Taurina/química
6.
Mikrochim Acta ; 186(12): 755, 2019 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-31707595

RESUMO

Platinum nanoparticles were loaded on CoSn(OH)6 nanocubes via a co-precipitation method. The material (NCs) is shown to be a viable peroxidase mimic that catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to generate oxidized TMB (oxTMB) with absorption at 652 nm. The formation of the blue color can be observed in <30 s. Thus, a visual and colorimetric assay was worked out for H2O2. It has a detection limit as low as 4.4 µM and works in the 5 to 200 µM concentration range. The method was also used to detect dopamine (DA) which is found to inhibit the enzyme mimicking activity of the NCs. Hence, less blue color is formed in its presence. The respective DA assay has a linear response in the 5.0 to 60 µM concentration range and a 0.76 µM detection limit. Graphical abstractSchematic diagram of a visual colorimetric method for determination of H2O2 and dopamine (DA) with the aid of color change of 3,3',5,5'-tetramethylbenzidine (oxTMB), based on the peroxidase-like activity of Pt/CoSn(OH)6 nanocubes.


Assuntos
Colorimetria/métodos , Dopamina/sangue , Nanopartículas Metálicas/química , Benzidinas/química , Catálise , Cobalto/química , Corantes/química , Humanos , Peróxido de Hidrogênio/química , Hidróxidos/química , Limite de Detecção , Oxirredução , Peroxidase/química , Platina/química , Estanho/química
7.
Mikrochim Acta ; 186(12): 751, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701250

RESUMO

Reduced graphene oxide containing Fe3O4 nanoparticles was decorated with hydroxypropyl-ß-cyclodextrin (HP-ß-CD) to construct a novel nanocomposite (3D-rGO/Fe3O4/HP-ß-CD). The composite was placed on a glassy carbon electrode (GCE) to design an electrochemical sensor for detecting simultaneously serotonin (5-HT), dopamine (DA), and ascorbic acid (AA). The interconnected porous reduced graphene oxide framework tightly anchored to the Fe3O4 magnetic nanoparticles warrants good electrical conductivity and efficient catalytic activity. The HP-ß-CD acts as a supramolecular host with high recognition ability for 5-HT, DA and AA. Well-separated oxidation peaks and increased peak currents were observed for 5-HT, DA, and AA individually and in mixtures by differential pulse voltammetry (DPV). The following figures of merit were found for simultaneous electrochemical determination of 5-HT, DA, and AA: (a) Well separated peaks at around 0.316, 0.16 and - 0.044 V; (b) linear responses in the 0.01 - 25 µM, 0.02 - 25 µM and 10 - 350 µM; (c) detection limits of 3.3 nM, 6.7 nM and 3.3 µM (S/N = 3), and (d) recoveries of 96.9-103%, 97.3%-102% and 96.3-105% from spiked serum samples, respectively. All relative standard deviation (RSD) are less than 4%. Graphical abstractSchematic representation of simultaneous detecting serotonin (5-HT), dopamine (DA) and ascorbic acid (AA) for three-dimensional reduced-graphene oxide/Fe3O4/hydroxypropyl-ß-cyclodextrin (3D-rGO/Fe3O4/HP-ß-CD) by differential pulse voltammetry (DPV) approach.


Assuntos
Ácido Ascórbico/sangue , Dopamina/sangue , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Serotonina/sangue , 2-Hidroxipropil-beta-Ciclodextrina/química , Ácido Ascórbico/química , Técnicas Biossensoriais/métodos , Dopamina/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Grafite/química , Células Hep G2 , Humanos , Limite de Detecção , Nanopartículas de Magnetita/química , Oxirredução , Serotonina/química
8.
Mikrochim Acta ; 186(12): 795, 2019 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-31734752

RESUMO

A glassy carbon electrode (GCE) was modified with nitrogen-enriched carbon frameworks decorated with palladium nanoparticles (Pd@NCF/GCEs). The modified GCE is shown to be a viable tool for determination of uric acid (UA) and dopamine (DA) in the presence of ascorbic acid (AA). The Pd@NCF was fabricated though one-step pyrolysis and characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy and nitrogen-adsorption/desorption analysis. The Pd@NCF/GCE was characterized by differential pulse voltammetry (DPV). Both UA and DA have pronounced oxidation peaks (at 360 mV for UA and 180 mV for DA, all vs. Ag/AgCl) in the presence of AA. Response is linear in the 0.5-100 µM UA concentration range and in the 0.5-230 µM DA concentration range. The detection limits are 76 and 107 nM, respectively (at S/N = 3). This electrode is stable, reproducible and highly selective. It was used for UA and DA determination in spiked serum samples. Graphical abstractSchematic representation of nitrogen-enriched carbon frameworks decorated with palladium nanoparticles co-modified glassy carbon electrode for simultaneous determination of dopamine and uric acid in the presence of ascorbic acid.


Assuntos
Ácido Ascórbico/química , Carbono/química , Dopamina/sangue , Nanopartículas Metálicas/química , Ácido Úrico/sangue , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Limite de Detecção , Nanocompostos/química , Nitrogênio/química , Paládio/química , Reprodutibilidade dos Testes
9.
J Vet Intern Med ; 33(6): 2587-2594, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31660652

RESUMO

BACKGROUND: Sudden acquired retinal degeneration syndrome (SARDS) has clinical similarity to pituitary-dependent hypercortisolism (PDH) in dogs. Some studies have identified a greater frequency of SARDS in seasons with reduced daylight hours. Neurohormone imbalances contribute to retinal lesions in other species, warranting further study in dogs with SARDS. HYPOTHESIS: Dysregulation of circulating melatonin concentration is present in dogs with SARDS but not in dogs with PDH. ANIMALS: Fifteen client-owned dogs with spontaneous SARDS (median time of vision loss 18 days), 14 normal dogs, and 13 dogs with confirmed PDH. PROCEDURES: Prospective case-control study. ELISA on samples (obtained in the morning) for measurement of plasma melatonin and dopamine, serum serotonin, urine 6-sulfatoxymelatonin (MT6s), and creatinine. Statistical analysis was performed using 1-way ANOVA, Spearman correlation and receiver operator characteristic area under the curve analysis. RESULTS: There were no significant differences in circulating melatonin, serotonin or dopamine concentrations between the 3 groups, although the study was underpowered for detection of significant differences in serum serotonin. Urine MT6s:creatinine ratio was significantly higher in dogs with PDH (4.08 ± 2.15 urine [MT6s] ng/mL per mg of urine creatinine) compared with dogs with SARDS (2.37 ± .51, P < .01), but not compared with normal dogs. CONCLUSIONS AND CLINICAL RELEVANCE: We have identified neurohormone differences between dogs with SARDS and PDH.


Assuntos
Doenças do Cão/sangue , Dopamina/sangue , Melatonina/sangue , Hipersecreção Hipofisária de ACTH/veterinária , Degeneração Retiniana/veterinária , Serotonina/sangue , Animais , Estudos de Casos e Controles , Doenças do Cão/metabolismo , Cães , Melatonina/análogos & derivados , Melatonina/urina , Hipersecreção Hipofisária de ACTH/sangue , Hipersecreção Hipofisária de ACTH/metabolismo , Estudos Prospectivos , Degeneração Retiniana/sangue , Degeneração Retiniana/metabolismo
10.
Planta Med ; 85(17): 1351-1362, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31559607

RESUMO

Atremorine is a novel bioproduct with neuroprotective effects on dopaminergic neurons and a natural L-DOPA donor in Parkinson's disease (PD). In the present study, we show the effects of a single dose of Atremorine (5 g, p. o.) on plasma dopamine (DA) response and brain function in PD (n = 183) and the influence that pathogenic (LRRK2), metabolic (CYP2D5, CYP2C9, CYP2C19, CYP3A5, NAT2), transporter (ABCB1), pleiotropic (APOE), and detoxifying genes (CYP1B1, GSTT1, GSTP1, GSTM1, SOD2) involved in the pharmacogenetic network exerts on Atremorine-induced DA response. Over 90% of PD patients at diagnosis show plasma DA levels below 20 pg/mL. Atremorine induces DA synthesis causing a significant increase in plasma DA levels 1 h after administration in practically 100% of patients. Females tend to show lower basal DA levels than males and the response of DA to Atremorine is stronger in males than in females. Atremorine-induced DA response is pharmacogenotype-specific and lasts from 6 - 12 h depending upon the pharmacogenetic profile of each patient. Genetic variants in pathogenic genes, metabolic genes, and genes involved in the detoxification processes affect the response of DA to Atremorine in a genotype-specific manner. Atremorine or any of its bioactive components can cross the blood-brain barrier and improve brain function and motor function, as revealed by the reduction in slow wave activity in brain mapping and psychometric assessment, respectively. Atremorine is a selective neuroprotective agent for dopaminergic neurons with prophylactic and therapeutic potential in PD.


Assuntos
Produtos Biológicos/uso terapêutico , Dopamina/sangue , Levodopa/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Transportadores de Cassetes de Ligação de ATP/genética , Sistema Enzimático do Citocromo P-450/genética , Eletroencefalografia , Feminino , Pleiotropia Genética , Variação Genética , Técnicas de Genotipagem , Glutationa Transferase/genética , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/sangue , Doença de Parkinson/genética , Vicia faba/química
11.
Eur J Paediatr Neurol ; 23(5): 685-691, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31522993

RESUMO

Phenylketonuric (PKU) patients are a population at risk for sleep disorders due to deficits in neurotransmitter synthesis. We aimed to study the prevalence of sleep disorders in early-treated PKU children and adolescents and assessed correlations with dopamine and serotonin status. We compared 32 PKU patients (16 females, 16 males; mean age 12 years), with a healthy control group of 32 subjects (16 females, 16 males; mean age 11.9 years). 19 PKU patients were under dietary treatment and 13 on tetrahydrobiopterin therapy. Concurrent phenylalanine (Phe), index of dietary control and variability in Phe in the last year, tyrosine, tryptophan, prolactin, and ferritin in plasma, platelet serotonin concentration, and melatonin, homovanillic and 5-hydroxyindoleacetic acid excretion in urine were analyzed. Sleep was assessed using Bruni's Sleep Disturbance Scale for Children. Sleep disorders were similar in both groups, 15.6% in control group and 12.5% in PKU group. In PKU patients, no correlations were found with peripheral biomarkers of neurotransmitter synthesis nor different Phe parameters, 43.3% had low melatonin excretion and 43.8% low platelet serotonin concentrations. Despite melatonin and serotonin deficits in early-treated PKU patients, the prevalence of sleep disorders is similar to that of the general population.


Assuntos
Dopamina/sangue , Fenilcetonúrias/complicações , Serotonina/sangue , Transtornos do Sono-Vigília/epidemiologia , Transtornos do Sono-Vigília/etiologia , Adolescente , Biomarcadores/sangue , Criança , Feminino , Humanos , Masculino , Melatonina/sangue , Fenilcetonúrias/sangue , Fenilcetonúrias/terapia , Prevalência , Transtornos do Sono-Vigília/sangue , Adulto Jovem
12.
Sensors (Basel) ; 19(18)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547244

RESUMO

A new fluorescent probe (BDP-Fe2+) was developed for targeting dopamine, with a boron-dipyrromethenyl (BDP) group as the fluorophore and a Fe2+ complex as the ligand exchange site. The free form of BDP-Fe2+ in solution displayed weak fluorescence emission, while it showed strong fluorescence emission after interaction with dopamine due to the release of Fe2+ from BDP-Fe2+, confirming the binding of Fe2+ to dopamine. The increase in fluorescence intensity was concentration-dependent, and a good linear relationship was observed between the fluorescence intensity and dopamine concentration. The detection limit of dopamine by BDP-Fe2+ was 1.1 nM, indicating a 20-fold higher sensitivity than that of previously reported compounds. The reaction of BDP-Fe2+ with dopamine was not affected by the presence of foreign substances, allowing the highly selective detection of dopamine in the human serum sample. The results of this study indicate that the novel compound BDP-Fe2+ is a reliable fluorescent molecular probe for the detection of dopamine and can be widely employed in diverse scientific areas.


Assuntos
Dopamina/sangue , Corantes Fluorescentes/química , Espectrometria de Fluorescência/métodos , Compostos de Boro/química , Humanos , Concentração de Íons de Hidrogênio , Ferro/química , Limite de Detecção , Metais/química
13.
Mikrochim Acta ; 186(8): 540, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31317272

RESUMO

The authors have modified a carbon paste electrode with Al2O3-supported palladium nanoparticles (PdNP@Al2O3) to obtain a sensor for simultaneous voltammetric determination of melatonin (MT), dopamine (DA) and acetaminophen (AC). The PdNP@Al2O3 was characterized by scanning electron microscopy and energy-dispersive X-ray spectra. The sensor can detect DA, AC, MT and their mixtures by giving distinct signals at working voltages of typically 236, 480 and 650 mV (vs. Ag/AgCl), respectively. Differential pulse voltammetric peak currents of DA, AC and MT increase linearly in the 50 nmol L-1 - 1.45 mmol L-1, 40 nmol L-1 -1.4 mmol L-1, and 6.0 nmol L-1 - 1.4 mmol L-1 concentration ranges. The limits of detection are 36.5 nmol L-1 for DA, 36.5 nmol L-1 for AC, and 21.6 nmol L-1 for MT. The sensor was successfully used to detect the analytes in (spiked) human serum and drug samples. Graphical abstract Schematic presentation of Al2O3-supported palladium nanoparticles (PdNP@Al2O3) for modification of a carbon paste electrode (CPE) to develop a voltammetric sensor for the simultaneous determination of dopamine (DA), acetaminophen (AC) and melatonin (MT).


Assuntos
Acetaminofen/análise , Óxido de Alumínio/química , Dopamina/análise , Melatonina/análise , Nanopartículas Metálicas/química , Paládio/química , Acetaminofen/sangue , Acetaminofen/química , Acetaminofen/urina , Carbono/química , Dopamina/sangue , Dopamina/química , Dopamina/urina , Técnicas Eletroquímicas , Eletrodos , Humanos , Melatonina/sangue , Melatonina/química , Melatonina/urina
14.
Hum Exp Toxicol ; 38(11): 1244-1253, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31319705

RESUMO

Prolactin (PRL) levels can usually be controlled by PRL-inhibiting psychiatric drugs that include anti-dopamine agents. However, the use of dopamine (DA) antagonists may lead to hyperprolactinemia under certain clinical conditions. The aim of this study was to investigate postmortem PRL levels as potential markers of drug abuse, especially that of DA antagonists, in autopsy cases. We examined 121 autopsy cases, excluding cases involving acute hypoxia/ischemia, such as asphyxia, because PRL concentrations are reportedly increased under acute hypoxic conditions. Detected drugs were classified as either DA antagonists, stimulants, psychotropic drugs other than DA antagonists, or other non-psychotropic drugs, and many cases had no detected drugs. Samples comprised blood collected from the right heart chamber and cerebrospinal fluid (CSF). PRL protein level was measured by chemiluminescent immunoassay, and PRL gene expression in the anterior pituitary of autopsy cases was analyzed by reverse transcription-polymerase chain reaction. The PRL-positive cell ratio in the anterior pituitary gland was also measured by immunohistochemical analysis. The results indicated that PRL levels in the serum and CSF were higher in DA antagonist cases than in other cases. PRL levels in the serum and CSF also correlated with the PRL gene expression in cases with abuse of DA antagonists. However, no significant difference in the PRL-positive cell ratio in the anterior pituitary gland was evident between any of the classes of drug-detected and drug-undetected cases. These results suggest that postmortem measurements of PRL transcription levels may be useful for diagnosing cases of DA antagonist use.


Assuntos
Antagonistas de Dopamina , Prolactina/genética , Transtornos Relacionados ao Uso de Substâncias/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Autopsia , Biomarcadores/sangue , Biomarcadores/líquido cefalorraquidiano , Criança , Pré-Escolar , Dopamina/sangue , Feminino , Expressão Gênica , Ginecomastia/sangue , Ginecomastia/líquido cefalorraquidiano , Ginecomastia/diagnóstico por imagem , Ginecomastia/genética , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Miocárdio/metabolismo , Prolactina/sangue , Prolactina/líquido cefalorraquidiano , Psicotrópicos , RNA Mensageiro/metabolismo , Transtornos Relacionados ao Uso de Substâncias/sangue , Transtornos Relacionados ao Uso de Substâncias/líquido cefalorraquidiano , Adulto Jovem
15.
Sensors (Basel) ; 19(14)2019 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-31337025

RESUMO

In this work, we report the development of a simple and sensitive sensor based on graphite screen-printed electrodes (GSPEs) modified by a nanocomposite film for dopamine (DA) detection. The sensor was realized by electrodepositing polyaniline (PANI) and gold nanoparticles (AuNPs) onto the graphite working electrode. The sensor surface was fully characterized by means of the cyclic voltammetry (CV) technique using [Fe(CN)6]4-/3- and [Ru(NH3)6]2+/3+ as redox probes. The electrochemical behavior of the nanocomposite sensor towards DA oxidation was assessed by differential pulse voltammetry (DPV) in phosphate buffer saline at physiological pH. The sensor response was found to be linearly related to DA concentration in the range 1-100 µM DA, with a limit of detection of 0.86 µM. The performance of the sensor in terms of reproducibility and selectivity was also studied. Finally, the sensor was successfully applied for a preliminary DA determination in human serum samples.


Assuntos
Dopamina/sangue , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Compostos de Anilina/química , Calibragem , Eletrodos , Ouro/química , Grafite/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Sondas Moleculares/química , Oxirredução , Reprodutibilidade dos Testes
16.
Anal Chim Acta ; 1077: 150-159, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307704

RESUMO

In this article, we demonstrate the potentiostatic electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) on reduced graphene oxide (RGO) to develop a nanocomposite-modified electrode that separates three coexisting biofluids - ascorbic acid (AA), dopamine (DA), and uric acid (UA) - in a 0.1 M Phosphate buffer solution at a physiological pH (7.4). The texture, physicochemical properties, and electrochemical behavior of the PEDOT-RGO were explored using UV-visible spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, electron microscopic techniques, and electrochemical impedance spectroscopy (EIS). A PEDOT-RGO/GCE was evaluated with respect to a bare GCE, RGO/GCE, and PEDOT/GCE for the simultaneous sensing of AA, DA, and UA. The difference in voltammetric peak potentials was about 180 mV between AA and DA and 120 mV between DA and UA. The differential pulse voltammetric sensor provided a linear calibration for a wide concentration range (0.1-907 µM for AA, 0.1-901 µM for DA, and 0.1-701 µM for UA) with detection limits of 1.5 µM, 0.6 µM, and 0.2 µM for AA, DA, and UA, respectively. The developed sensor was validated by the detection of AA, DA, and UA in a vitamin C tablet, a dopamine hydrochloride injection, and human serum samples.


Assuntos
Ácido Ascórbico/sangue , Compostos Bicíclicos Heterocíclicos com Pontes/química , Dopamina/sangue , Grafite/química , Nanocompostos/química , Polímeros/química , Ácido Úrico/sangue , Ácido Ascórbico/química , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Carbono/química , Dopamina/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/síntese química , Humanos , Limite de Detecção , Oxirredução , Polímeros/síntese química , Reprodutibilidade dos Testes , Ácido Úrico/química
17.
Mater Sci Eng C Mater Biol Appl ; 103: 109788, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349446

RESUMO

Electrochemical properties of dopamine, uric acid and ascorbic acid have been investigated using gold nano particles (AuNPs) decorated functionalized multiwall carbon nanotubes (MWCNTs) nano composite modified electrode. MWCNTs were acid functionalized to introduce -COOH functionalities. The functionalized MWCNTs were used as support materials and were decorated with gold nano particles of 20 nm in size. The nano composite materials thus prepared have been named as f-MWCNTs/AuNPs composite. The composite material was characterized using FTIR, RAMAN, TEM, UV-VIS spectroscopy and atomic force microscopy measurements. Electrochemical investigations on the composite modified glassy carbon electrode for dopamine was investigated in presence of interfering agents like ascorbic acid and uric acid. The modified electrode showed sensitivity of 0.002 µAnM-1 for dopamine with the detection limit of 35 nM. Present electrode showed high selectivity for dopamine as the oxidation peak of dopamine and uric acid were very well resolved. The analytical method was found to be suitable for the simultaneous determination of dopamine and uric acid using the modified electrode. Method was applied in spiked real serum sample for the determination of dopamine.


Assuntos
Dopamina/análise , Técnicas Eletroquímicas/métodos , Ouro/química , Nanotubos de Carbono/química , Ácido Ascórbico/química , Catálise , Dopamina/sangue , Eletrodos , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Oxirredução , Ácido Úrico/química
18.
Analyst ; 144(15): 4526-4533, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31243397

RESUMO

Development of analytical methods allowing sensitive detection of neurotransmitters in various biofluids is vital. However, limitations of these methods include interference of impurities and stringent requirements concerning sample purity. In the current work, we developed a strategy for the rapid and sensitive analysis of dopamine (DA) in various biofluids with a smart surface-enhanced Raman spectroscopy (SERS) probe composed of magnetite Fe3O4 and Au nanoparticles (Fe3O4/Au NPs). Besides the simple and quick separation of DA from the specimen, Fe3O4 not only enabled a specific chemical interaction with DA molecules, but also acted as a SERS substrate capable of electromagnetically enhancing the Raman signal of DA. Therefore, the Fe3O4/Au NP composite with its coexisting electric-field effect and charger transfer (CT) enhancement was found to be beneficial for capturing the target molecules in biological environments and then enhancing the DA sensitivity. To understand the strong binding interaction between Fe3O4/Au and DA, X-ray photoelectron spectroscopy (XPS) was carried out, specifically to illuminate the chemical adsorption or possible CT complex. Moreover, a rapid purification strategy for further separating DA from serum was developed, and thus a high nanometer-level sensitivity was achieved. In addition, the feasibility of using Fe3O4/Au combined with the developed purification method was also verified using various tissue homogenates spiked with DA molecules. Such a nanocomposite can offer the possibility of efficiently separating DA from the complex specimen and then providing the sensitive detection of DA for various tissues. Accordingly, the smart SERS Fe3O4/Au nanocomposite probe, with its advantages of simple pre-treatment and synergetic enhanced mechanisms, shows great promise for the rapid and sensitive detection of DA in complicated specimens.


Assuntos
Dopamina/sangue , Ouro/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Adsorção , Humanos , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos
19.
Molecules ; 24(12)2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31238523

RESUMO

Copper nanowires (Cu NWs) were modified with graphene oxide (GO) nanosheets to obtain a sensor for simultaneous voltammetric determination of ascorbic acid (AA), dopamine (DA) and acetaminophen (AC). The nanocomposite was obtained via sonication, and its structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical oxidation activity of the materials (placed on a glassy carbon electrode) was studied by cyclic voltammetry and differential pulse voltammetry. Due to the synergistic effect of Cu NWs and GO, the specific surface, electrochemical oxidation performance and conductivity are improved when compared to each individual component. The peaks for AA (-0.08 V), DA (+0.16 V), and AC (+0.38 V) are well separated. The sensor has wide linear ranges which are from 1-60 µM, 1-100 µM, and 1-100 µM for AA, DA, and AC, respectively, when operated in the differential pulse voltammetric mode. The detection limits are 50, 410 and 40 nM, respectively. Potential interferences by uric acid (20 µM), glucose (10 mM), NaCl (1 mM), and KCl (1 mM) were tested for AA (1 µΜ), DA (1 µΜ), and AC (1 µΜ) and were found to be insignificant. The method was successfully applied to the quantification of AA, DA, and AC in spiked serum samples.


Assuntos
Cobre/química , Técnicas Eletroquímicas , Grafite/química , Nanoestruturas/química , Nanofios/química , Acetaminofen/sangue , Acetaminofen/metabolismo , Ácido Ascórbico/sangue , Ácido Ascórbico/metabolismo , Técnicas Biossensoriais , Dopamina/sangue , Dopamina/metabolismo , Humanos , Nanoestruturas/ultraestrutura , Nanofios/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Anim Reprod Sci ; 207: 73-82, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31208851

RESUMO

A dopamine type-2 receptor (DRD2) SNP, previously found to be correlated with serum prolactin (PRL) concentrations in cattle, was evaluated for impact on growth traits, serum prolactin concentration, and semen quality. Over a four-year period, yearling beef bulls were allowed diets containing or lacking ergot alkaloids (EA). Every 21 or 28 d semen was collected for semen motility and morphology assessment and blood samples were collected to measure serum PRL concentrations. In addition, body condition score and scrotal circumference were evaluated. Serum PRL concentrations were assessed using a radioimmunoassay. In the first year, all bulls were sacrificed at the end of a 126-day study. Testicles and epididymis were collected at the end of the study or 60 days after removal from treatment. Immunohistochemistry was performed on testis, epididymis, and sperm cells, incubated with or without a primary antibody for DRD2 and counterstained with DAPI. Isolation of DNA was performed on sperm pellets using DNAzol (Thermo Fisher Scientific, Waltham, MA, USA) methods. Polymerase chain reaction was performed to amplify the region of the DRD2 gene containing the SNP of interest. The products were subjected to restriction fragment length polymorphism analysis. Further, all samples were subjected to genotyping using a custom Taqman genotyping assay (Applied Biosystems, Foster city, CA, USA). The presence of DRD2 was detected in the testis, epididymis, and sperm cells. The DRD2 genotype was not associated with semen quality, serum PRL, or growth traits. Consumption of EA resulted in lesser PRL serum concentrations but had no effect on values for other variable examined.


Assuntos
Bovinos , Agonistas de Dopamina/farmacologia , Crescimento e Desenvolvimento , Polimorfismo de Nucleotídeo Único , Prolactina/sangue , Receptores de Dopamina D2/genética , Sêmen/efeitos dos fármacos , Animais , Constituição Corporal/genética , Bovinos/sangue , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Dopamina/sangue , Genótipo , Crescimento e Desenvolvimento/efeitos dos fármacos , Crescimento e Desenvolvimento/genética , Masculino , Sêmen/metabolismo , Sêmen/fisiologia , Análise do Sêmen/veterinária , Motilidade Espermática/efeitos dos fármacos , Motilidade Espermática/genética
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