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Article in English | WPRIM | ID: wpr-927655


Objective@#To develop effective alternatives to natural enzymes, it is crucial to develop nanozymes that are economical, resource efficient, and environmentally conscious. Carbon nanomaterials that have enzyme-like activities have been extensively developed as substitutes for traditional enzymes.@*Methods@#Carbide-derived carbons (CDCs) were directly synthesized via a one-step electrochemical method from a MAX precursor using an ammonium bifluoride electrolyte at ambient conditions. The CDCs were characterized by systematic techniques.@*Results@#CDCs showed bienzyme-like activities similar to that of peroxidase and superoxide dismutase. We systematically studied the dependence of CDC enzyme-like activity on different electrolytes and electrolysis times to confirm activity dependence on CDC content. Additionally, the synthesis mechanism and CDC applicability were elaborated and demonstrated, respectively.@*Conclusion@#The demonstrated synthesis strategy eliminates tedious intercalation and delamination centrifugation steps and avoids using high concentrations of HF, high temperatures, and halogen gases. This study paves the way for designing two-dimensional material-based nanocatalysts for nanoenzyme and other applications.

Ammonium Compounds/chemical synthesis , Carbon/chemistry , Electrochemical Techniques , Enzymes , Fluorides/chemical synthesis , Humans , Nanostructures , Oxidation-Reduction
Article in Chinese | WPRIM | ID: wpr-880404


Breast cancer is one of the most serious diseases threatening women's life and health in the world, and the mortality rate is the second in the world. With the progress of nanotechnology and the advantages of nanomaterials in the field of electrochemistry and biosensor, various nanomaterials have been applied in electrochemical biosensors. This makes the electrochemical nano-biosensor in the field of rapid detection of breast cancer has been widely concerned and studied. This paper introduces the important components of electrochemical nano-biosensor for breast cancer detection and the research progress of each component in breast cancer detection, as well as the performance of electrochemical nano biosensor in breast cancer detection and the prospect of its application.

Biosensing Techniques , Breast Neoplasms/diagnosis , Electrochemical Techniques , Female , Humans , Nanostructures , Nanotechnology
Article in Chinese | WPRIM | ID: wpr-878790


A highly specific electrochemical biosensor based on T-Hg~(2+)-T structure for fast screening trace Hg~(2+) in complex animal drug matrix was constructed by cyclic voltammetry(CV) and differential pulse voltammetry(DPV). In the presence of Hg~(2+), it can be specifically binded to the T base of DNA sequence on the surface of modified gold electrode, which changes the conformation of DNA molecule and the electrochemical signal. The concentration ratio of EDC/NHS, the concentration ratio of FC-DNA and the reaction time of the biosensor were optimized by the index of sensitivity and reproducibility in CV. The results showed that the stability of the biosensor was good within 3 days(RSD≤1.3%), the difference between batches was low(RSD=4.7%), and the specificity of the biosensor was high in the presence of interfering ions(As~(3+), Cd~(2+), Cu~(2+), Pb~(2+), Zn~(2+) and Fe~(3+)). DPV results showed that the peak current signal value has a linear relationship with the lgC_((Hg)) over a concentration range from 0.1 nmol·L~(-1) to 1.0 μmol·L~(-1) with a detection limit of 0.066 nmol·L~(-1). Finally, the recovery rate tested in the matrix of animal medicine was satisfactory as 99.17%-101.3%, which can meet the needs of the determination of trace Hg~(2+) in the matrix of Bombyx Batryticatus, and provide a new idea for the rapid screening of trace heavy metals in the matrix of other types of complex traditional Chinese medicine.

Animals , Biosensing Techniques , DNA/genetics , Electrochemical Techniques , Gold , Mercury , Reproducibility of Results
Rev. bras. cir. cardiovasc ; 34(4): 464-471, July-Aug. 2019. tab
Article in English | LILACS | ID: biblio-1020500


Abstract Objective: Cerebrospinal fluid (CSF) drainage is a technique that has significantly reduced the incidence of spinal cord ischaemia (SCI). We present results of a systematic review to assess the literature on this topic in relation to thoracoabdominal aortic aneurysm repair (TAAR). Methods: Major medical databases were searched to identify papers related to CSF biomarkers measured during TAAAR. Results: Fifteen papers reported measurements of CSF biomarkers with 265 patients in total. CSF biomarkers measured included S-100ß, neuron-specific endolase (NSE), lactate, glial fibrillary acidic protein A (GFPa), Tau, heat shock protein 70 and 27 (HSP70, HSP27), and proinflammatory cytokines. Lactate and S-100ß were reported the most, but did not correlate with SCI, which was also the case with NSE and TAU. GFPa showed significant CSF level rises, both intra and postoperative in patients who suffered SCI and warrants further investigation, similar results were seen with HSP70, HSP27 and IL-8. Conclusions: Although there is significant interest in this topic, there still remains a significant lack of high-quality studies investigating CSF biomarkers during TAAR to detect SCI. A large and multicentre study is required to identify the significant role of each biomarker.

Humans , Phosphopyruvate Hydratase/blood , Biomarkers/cerebrospinal fluid , Aortic Aneurysm, Thoracic/surgery , Spinal Cord Ischemia/cerebrospinal fluid , Electrochemical Techniques/methods , Biomarkers/blood , S100 Proteins/cerebrospinal fluid , S100 Proteins/blood , Drainage , Lactic Acid/cerebrospinal fluid , Lactic Acid/blood , Spinal Cord Ischemia/blood
Int. j. cardiovasc. sci. (Impr.) ; 32(3): 238-246, May-June 2019. graf
Article in English | LILACS | ID: biblio-1002226


Grapes and its derivatives (wines and juices) are rich in polyphenols that have high antioxidant and vasodilator capacity. These biological activities may vary in the juices marketed and produced in different regions of Brazil. Objectives: To determine the antioxidant and vasorelaxant effects of grape juice samples produced in different regions of Brazil. Methods: The content of phenolic compounds and antioxidant capacity were evaluated by the methods of Folin-Ciocalteau, DPPH, ABTS and a new electroanalytical approach (differential pulse voltammetry - DPV). Vasodilator effects were analyzed in isolated aorta from rats in an organ bath. Results: The samples from RJ and SP presented respectively the higher and lower phenolic content and also antioxidant capacity by the methods used (ABTS and DPPH). The results of the electrochemical index corroborate to the other tests, with the best results to RJ (21.69 ± 3.15 µA/V) and worse to the SP sample (11.30 ± 0.52 µA/V). In the vascular reactivity studies, the relaxation induced by each sample presented more distinct differences, following the order: RJ (87.9 ± 4.8%) > RS1 (71.6 ± 8.6%) > GO (56.2 ± 7.2%) > SP (39.9 ± 7.8%) > PR (39.4 ± 9.5%) > RS2 (19.5 ± 6.2%). Inhibition of endothelial NO practically abolished (p < 0.001) the relaxation for all samples, except one. Conclusion: The phenolic content and antioxidant capacity vary greatly among samples. The results obtained for the order of antioxidant activity were: RJ > RS1 > GO > RS2 > PR > SP. The juices were able to induce vascular relaxation at quite varied levels, and the RJ sample the most effective. The L-NAME practically blocked all samples except one (RS2)

Animals , Rats , Vasodilation , Vasodilator Agents/analysis , Brazil/epidemiology , Vitis , Antioxidants/pharmacology , Cardiovascular Diseases/prevention & control , Analysis of Variance , Rats, Wistar , Models, Animal , Endothelial Cells , Electrochemical Techniques , Polyphenols , Fruit and Vegetable Juices/analysis , Hypertension , Neoplasms/prevention & control
Article in Chinese | WPRIM | ID: wpr-775345


A new composite organic oscillating reaction system based on BrO₃-Ce(SO₄)₂-H₂SO₄-malonic acid/tartaric acid was proposed in this paper. On the basis of the influence of the concentration of each component on the stability and characteristic parameters of the blank system, the electrochemical fingerprints of 30 kinds of traditional Chinese medicines (TCM) were obtained. The results showed that the electrochemical fingerprint can be used for the identification of TCMs, the distinguishment of different parts and the appraisal of genuineness, which is fast, sensitive and accurate. At the same time, we explored and verified the mechanism of oscillation and the formation mechanism of TCM fingerprint.

Drugs, Chinese Herbal , Chemistry , Electrochemical Techniques , Malonates , Chemistry , Medicine, Chinese Traditional , Phytochemicals , Tartrates , Chemistry
An. acad. bras. ciênc ; 89(3): 1381-1389, July-Sept. 2017. tab, graf
Article in English | LILACS | ID: biblio-886739


ABSTRACT A new modified electrode for indirect sensing of OH· and radical scavengers was described. The electrochemical polymerization of methylene blue in aqueous solutions and the properties of the resulting films on a glassy carbon electrode were carried out using cyclic voltammetry. A surface coverage of 1.11 × 109mol cm2 was obtained, revealing a complete surface coverage of the polymeric film on the electrode surface. OH· was able to destroy the poly(methylene blue) film by exposure to a Fenton solution. The loss of the electrochemical signal of the residual polymeric film attached to the electrode surface was related to the extent of its dissolution. The applicability of the sensor was demonstrated by evaluating the OH radical scavenging effect on different concentrations of ascorbic acid. The obtained radical scavenging capacity were 31.4%, 55.7%, 98.9% and 65.7% for the ascorbic acid concentrations of 5, 10, 30 and 50 mM, respectively.

Free Radical Scavengers/chemistry , Methylene Blue/chemistry , Structure-Activity Relationship , Electrodes , Electrochemical Techniques
Article in Korean | WPRIM | ID: wpr-7569


BACKGROUND: Self-monitoring of blood glucose plays an important role in management of diabetes mellitus. Blood glucose measurement is based on using plasma glucose separated from whole blood, but many people with diabetes and health care providers use a portable glucose meter for convenience. The aim of this study was to evaluate the accuracy and agreement of G300 portable glucose monitoring system against standard venous glucose testing methods, based on ISO 15197:2013 standards. METHODS: This study was the evaluation of G300 system accuracy following ISO 15197:2013 standards. We estimated precision, system accuracy, hematocrit interference, interfering substances, and user performance. RESULTS: In repeatability precision evaluation of those glucometers, standard deviation was 2.9–3.7 mg/dL at glucose levels under 100 mg/dL and coefficient of variation was 1.7–3.2% at glucose levels over 100 mg/dL, respectively. In accuracy evaluation, 99.5% of difference values between results of G300 portable glucose monitoring system and clinical laboratory were within 95%. Consensus Error grid analysis showed that all values (100%) are within zone A. Hematocrit range between 20% and 60% did not cause interference. These results were acceptable for the ISO15197:2013 criteria in all glucose concentrations. CONCLUSIONS: This study showed that G300 can provide reliable blood glucose results for patients and health care providers to manage diabetes mellitus, satisfying the ISO 15197:2013 criteria.

Blood Glucose Self-Monitoring , Blood Glucose , Capillaries , Consensus , Diabetes Mellitus , Electrochemical Techniques , Fasting , Glucose , Health Personnel , Hematocrit , Humans
Rev. Fac. Odontol. Univ. Antioq ; 28(1): 54-70, July-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-957227


ABSTRACT Introduction: nickel-titanium (nitinol) wires may potentially corrode oral environments causing biocompatibility problems. The purpose of this study was to compare the behavior of corrosion of nitinol wires in artificial saliva with different levels of pH, fluoride concentration, and tension degrees. Methods: an experimental study applying four electrochemical techniques: corrosion potential, linear polarization resistance, Tafel curves, and electrochemical impedance spectroscopy. Samples were cemented on teeth simulating different crowding degrees (56 gf and 224 gf) at various levels of fluoride concentration (0% and 0.5%) and pH (4 and 7). Results: the corrosion strength values for a sample submerged at pH 4, 0% NaF during 5 hours is lower for a force of 224 gf than for 56 gf. When the electrolyte is added a concentration of 0.5% sodium fluoride, it increases polarization resistance for a force of 224 gf. Conclusion: this study confirmed the existence of oxides on the nickel-titanium surface, especially on the arch exposed for 14 days to pH 4 and 0.5% NaF.

RESUMEN Introducción: los alambres de níquel-titanio (nitinol) poseen potencial de corrosión en el medio bucal y pueden ocasionar problemas de biocompatibilidad. El propósito de este estudio fue comparar el comportamiento de corrosión que presentan los alambres de nitinol en saliva artificial con diferentes niveles de pH, concentración de fluoruros y grados de tensión. Métodos: se desarrolló un estudio de tipo experimental, aplicando cuatro técnicas electroquímicas: potencial de corrosión, resistencia a la polarización lineal, curvas de Tafel y espectroscopía de impedancia electroquímica. Los especímenes fueron cementados en dientes que simulaban diferentes grados de apiñamiento (56 gf y 224 gf), a diversos niveles de concentración de fluoruros (0% y 0,5%) y pH (4 y 7). Resultados: se observó que el valor de resistencia a la corrosión para una muestra sumergida a pH 4, 0% NaF y a 5 horas de inmersión es menor para la fuerza de 224 gf que para la de 56 gf. Cuando se le agrega al electrolito la concentración de fluoruro de sodio de 0,5%, aumenta la resistencia a la polarización para una fuerza equivalente de 224 gf. Conclusiones: se confirmó la existencia de óxidos sobre la superficie del níquel-titanio, especialmente en el arco expuesto durante 14 días a pH 4 y 0,5% en peso de NaF.

Fluorosis, Dental , Electrochemical Techniques , Fluorides
Chinese Medical Journal ; (24): 253-258, 2016.
Article in English | WPRIM | ID: wpr-310669


<p><b>BACKGROUND</b>It is often challenging to distinguish tuberculous pleural effusion (TPE) from malignant pleural effusion (MPE); thoracoscopy is among the techniques with the highest diagnostic ability in this regard. However, such invasive examinations cannot be performed on the elderly, or on those in poor physical condition. The aim of this study was to explore the differential diagnostic value of carbohydrate antigen 125 (CA125), carbohydrate antigen 199 (CA199), carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), and squamous cell carcinoma (SCC) associated antigen in patients with TPE and MPE.</p><p><b>METHODS</b>Using electrochemiluminescence, we measured the concentration of tumor markers (TMs) in the pleural effusion and serum of patients with TPE (n = 35) and MPE (n = 95). We used receiver operating characteristic (ROC) curve analysis to evaluate the TMs and differentiate between TPE and MPE.</p><p><b>RESULTS</b>The cut-off values for each TM in serum were: CA125, 151.55 U/ml; CA199, 9.88 U/ml; CEA, 3.50 ng/ml; NSE, 13.27 ng/ml; and SCC, 0.85 ng/ml. Those in pleural fluid were: CA125, 644.30 U/ml; CA199, 12.08 U/ml; CEA, 3.35 ng/ml; NSE, 9.71 ng/ml; and SCC, 1.35 ng/ml. The cut-off values for the ratio of pleural fluid concentration to serum concentration (P/S ratio) of each TM were: CA125, 5.93; CA199, 0.80; CEA, 1.47; NSE, 0.76; and SCC, 0.90. The P/S ratio showed the highest specificity in the case of CEA (97.14%). ROC curve analysis revealed that, for all TMs, the area under the curve in pleural fluid (0.95) was significantly different from that in serum (0.85; P < 0.001).</p><p><b>CONCLUSIONS</b>TMs in TPE differ significantly from those in MPE, especially when detected in pleural fluid. The combined detection of TMs can improve diagnostic sensitivity.</p>

Adult , Aged , Aged, 80 and over , Antigens, Neoplasm , Antigens, Tumor-Associated, Carbohydrate , Blood , Biomarkers, Tumor , Blood , CA-125 Antigen , Carcinoembryonic Antigen , Blood , Electrochemical Techniques , Female , Humans , Luminescent Measurements , Male , Middle Aged , Pleural Effusion , Blood , Pleural Effusion, Malignant , Blood , Young Adult
Braz. j. biol ; 75(4,supl.2): 37-42, Dec. 2015. tab, graf
Article in English | LILACS | ID: lil-769600


The present study analyzed the efficiency of the photo-electro-oxidation process as a method for degradation and inactivation of adenovirus in water. The experimental design employed a solution prepared from sterile water containing 5.107 genomic copies/L (gc/L) of a standard strain of human adenovirus type 5 (HAdV-5) divided into two equal parts, one to serve as control and one treated by photo-electro-oxidation (PEO) for 3 hours and with a 5A current. Samples collected throughout the exposure process were analyzed by real-time polymerase chain reaction (qPCR) for viral genome identification and quantitation. Prior to gene extraction, a parallel DNAse treatment step was carried out to assess the integrity of viral particles. Integrated cell culture (ICC) analyses assessed the viability of infection in a cell culture. The tested process proved effective for viral degradation, with a 7 log10 reduction in viral load after 60 minutes of treatment. The DNAse-treated samples exhibited complete reduction of viral load after a 75 minute exposure to the process, and ICC analyses showed completely non-viable viral particles at 30 minutes of treatment.

Resumo O presente estudo analisou a eficiência do processo de fotoeletrooxidação como metodologia para a degradação e inativação de adenovírus em água. A concepção experimental emprega uma solução preparada a partir de água estéril contendo 5,107 cópias genômicas/L (gc/L) de uma amostra padrão de adenovírus humano tipo 5 (HAdV-5), dividida em duas partes iguais, uma para servir como controle e outra tratada por fotoeletrooxidação (PEO) durante 3 horas e com uma corrente de 5A. As amostras recolhidas durante o processo de exposição foram analisadas por PCR quantitativo em tempo real (qPCR) para identificação e quantificação do genoma viral. Antes da extração de ácidos nucleicos, um passo de tratamento com DNAse paralelo foi realizado para avaliar a integridade das partículas virais. Um ensaio de qPCR integrado à cultura de células (ICC-qPCR) permitiu analisar a viabilidade de infecção em uma cultura de células. O processo mostrou-se eficaz testada para a degradação viral, com uma redução de 7 log10 da carga viral após 60 minutos de tratamento. As amostras tratadas com DNAse exibiram redução completa da carga viral após uma exposição de 75 minutos ao processo, e a análise de ICC-qPCR mostrou partículas virais completamente não-viáveis ​​em 30 minutos de tratamento.

Adenoviruses, Human/isolation & purification , Virus Inactivation , Waste Disposal, Fluid/methods , Water Purification/methods , Electrochemical Techniques , Oxidation-Reduction , Photolysis , Real-Time Polymerase Chain Reaction
Braz. j. biol ; 75(4,supl.2): 53-61, Dec. 2015. tab, graf
Article in English | LILACS | ID: lil-769601


The advanced oxidation process (AOP) is used to increase the treatment efficiency of effluents however, it is necessary to compare the toxicity of treated and untreated effluents to evaluate if the decontamination process does not cause any biological harm. Cultured cells have been previously used to assess the genotoxic and cytotoxic potential of various compounds. Hence, the aim of this work was to assess the applicability of cytotoxicity assays to evaluate the toxicity related to the AOP treatment. Samples of an industrial effluent were collected after their treatment by a conventional method. Cytotoxicity of standard and AOP treated effluents was assessed in CRIB and HEp-2 cell line using the MTT and neutral red assays. We observed decrease at cell viability in the both assays (50% MTT and 13% NRU) when cells were exposed to the AOP treatment in the highest concentration. Thus, cytotoxic assays in cultured cells can be explored as an useful method to evaluate toxicity as well as to optimize effluents treatment process.

Resumo O processo de oxidação avançada (POA) tem sido usado para aumentar a eficiência do tratamento de efluentes; no entanto, é necessário comparar a toxicidade de efluentes tratados e não tratados para avaliar se o processo de descontaminação não é capaz de causar algum risco biológico. Cultivos celulares têm sido utilizados para avaliar o potencial genotóxico e citotóxico de vários compostos. Assim, o objetivo deste trabalho foi avaliar a aplicabilidade de ensaios de citotoxicidade para avaliar a toxicidade relacionada ao tratamento com POA. As amostras de um efluente industrial foram recolhidas após o tratamento por um método convencional. A citotoxicidade dos efluentes padrão e tratado com POA foi avaliada nas linhagens celulares CRIB e HEp-2 usando os ensaios do MTT e do vermelho neutro. Observou-se diminuição da viabilidade celular em ambos os ensaios (50% MTT e 13% VN) quando as células foram expostas à concentração mais elevada do efluente tratado com POA. Assim, os ensaios de citotoxicidade em cultivos celulares podem ser explorados como um método útil para avaliar a toxicidade, bem como para otimizar os processos de tratamento de efluentes.

Animals , Cattle , Humans , Cytotoxins/toxicity , Photolysis , Waste Water/toxicity , Water Pollutants, Chemical/toxicity , Cell Line , Cell Survival/drug effects , Electrochemical Techniques , Industrial Waste/analysis , Oxidation-Reduction , Tanning , Toxicity Tests
Clinics ; 70(9): 612-617, Sept. 2015. tab, ilus
Article in English | LILACS | ID: lil-759291


OBJECTIVE:Procalcitonin is a reliable biomarker of infection and sepsis. We aimed to determine whether tracheotomy influences the procalcitonin concentrations in patients without sepsis and assess whether operative duration and procedure affect the peak procalcitonin level.METHODS:A total of 38 non-septic patients who required a tracheotomy underwent either a percutaneous dilatational tracheotomy (n=19) or a surgical tracheotomy (n=19). Procalcitonin levels were measured at the beginning of the tracheotomy and at 2 h, 4 h, 8 h, 24 h, 48 h and 72 h after the procedure.RESULTS:The baseline procalcitonin concentration before the tracheotomy was 0.24±0.13 ng/mL. The postoperative levels increased rapidly, with a 4-fold elevation after 2 h, reaching a peak 4 h later with a 5-fold increase over baseline. Thereafter, the levels gradually returned to 2-fold greater than the baseline level within 72 h. The peak levels of procalcitonin showed a significant positive correlation with operative durations (r=0.710, p<0.001) and procedures (rho=0.670, p<0.001).CONCLUSION:In patients without sepsis, tracheotomy induces a rapid release of serum procalcitonin, and the operative duration and procedure have significant impacts on the peak procalcitonin levels. Thus, the nonspecific increase in procalcitonin levels following tracheotomy needs to be considered when this measure is used to evaluate infection.

Adult , Aged , Female , Humans , Male , Middle Aged , Calcitonin/blood , Protein Precursors/blood , Sepsis/blood , Tracheotomy , Biomarkers/blood , Electrochemical Techniques , Luminescent Measurements , Operative Time , Prospective Studies , Time Factors
Rev. chil. endocrinol. diabetes ; 8(3): 102-107, jul. 2015. graf, tab
Article in Spanish | LILACS | ID: lil-789372


Cortisol is a glucocorticoid hormone with circadian cycle, it shows high levels in the morning and lower in the night. The salivary cortisol is the biologically active fraction and night measurement has been very useful for improving the diagnosis of Cushing’s syndrome, an endocrine disorder characterized by high levels of cortisol and loss of their circadian cycle. A disadvantage of this measurement is the establishment of reference ranges, which depends on the population and technique. Therefore the night salivary cortisol values were determined in a sample of 75 healthy volunteers, aged 18-75 years old. Each volunteer collects two samples in consecutive days and these samples were analyzed by electrochemiluminescence. The average of night salivary cortisol of volunteers was 0.165 +/- 0.059 ug/dL with a range from 0.082 to 0.352 ug/dL and no significant differences were found between two samples of cortisol in day 1 and 2. Our results suggest that the proposed cut-off limit 0.32 ug/dL between patients with and without Cushing Syndrome would be suitable for this technique and in our population.

Humans , Male , Adolescent , Adult , Female , Young Adult , Middle Aged , Hydrocortisone/analysis , Luminescent Measurements/methods , Saliva/chemistry , Electrochemical Techniques/methods , Circadian Rhythm
Braz. j. pharm. sci ; 51(2): 429-437, Apr.-June 2015. tab, ilus
Article in English | LILACS | ID: lil-755057


In this approach, a new voltammetric method for determination of norfloxacin was proposed with high sensitivity and wider detection linear range. The used voltammetric sensor was fabricated simply by coating a layer of graphene oxide (GO) and Nafion composited film on glassy carbon electrode. The advantage of proposed method was sensitive electrochemical response for norfloxacin, which was attributed to the excellent electrical conductivity of GO and the accumulating function of Nafion under optimum experimental conditions, the present method revealed a good linear response for determination of norfloxacin in the range of 1×10-8mol/L-7×10-6 mol/L with a detection limit of 5×10-9 mol/L. The proposed method was successfully applied in the determination of norfloxacin in capsules with satisfactory results...

Propos-se, por essa abordagem, novo método voltamétrico, com alta sensibilidade e faixa linear de detecção mais ampla, para a determinação de norfloxacino. O sensor voltamétrico utilizado foi fabricado simplismente por cobertura de camada de óxido de grafeno (GO) e filme de Nafion em eletrodo de cabrono vítreo. A vantagem do método proposto foi a resposta eletroquímica sensível para o norfloxacino, atribuída à condutividade elétrica excelente do GO e à função acumulada do Nafion. Sob condições experimentais ótimas, o presente método revelou boa resposta linear para a determinação do norfloxacino na faixa de limite de detecção de 1×10-8mol/L-7×10-6 mol/L. O método proposto foi aplicado com sucesso na determinação de norfloxacino em cápsulas, com resultados satisfatórios...

Humans , Norfloxacin/analysis , Chemistry, Pharmaceutical/methods , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods
Braz. j. pharm. sci ; 51(2): 285-294, Apr.-June 2015. tab, ilus
Article in English | LILACS | ID: lil-755069


This article describes a differential pulse voltammetric (DPV) method for the determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electro-oxidation of diclofenac at platinum electrode in 0.1 M TBAClO4/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL-1and 2-20 μg mL-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.87, and accuracy (relative error) was better than 4.12%. The method developed in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. In addition, the proposed technique was successfully applied to spiked human serum samples. No electro-active interferences from the endogenous substances were found in human serum...

Este artigo descreve um método de voltametria de pulso diferencial (VPD) para a determinação de diclofenaco em preparações farmacêuticas e em soro humano. O método proposto foi baseado em eletroxidação de diclofenaco no eléctrodo de platina em solução 0,1 M TBAClO4/acetonitrila. Dois picos de oxidação bem definidos foram observados em 0,87 e 1,27 V, respectivamente. As curvas de calibração obtidas utilizando-se valores de corrente medidos por segundo pico foram lineares no intervalo de concentração de 1,5-17,5 μg mL-1e 2-20 μg mL-1em eletrólito suporte e soro, respectivamente. Precisão e exatidão também foram verificadas em todos os meios. Valores de precisão intra- e inter-dia para o diclofenaco foram inferiores a 3.87 e a precisão (erro relativo) foi melhor do que 4,12%. O método desenvolvido neste estudo é exato, preciso e pode ser facilmente aplicado a Diclomec, Dicloflam e comprimidos Voltaren, como preparação farmacêutica. Além disso, a técnica proposta foi aplicada com sucesso em amostras de soro humano. Não se observaram interferências das substâncias endógenas no soro humano...

Humans , Diclofenac/analysis , Diclofenac/pharmacology , Diclofenac/blood , Clinical Chemistry Tests/methods , Chemistry, Pharmaceutical/methods , Electrochemical Techniques/methods
Ciênc. saúde coletiva ; 20(4): 1143-1148, 04/2015. tab
Article in English | LILACS | ID: lil-744866


The control of HIV / Tuberculosis (TB) co -infection remains a challenge for public health. Notification is mandatory for both diseases and the National Case Registry Database (Sinan) is responsible for the collection and processing of individual forms of reporting and monitoring. The adequate fulfillment of these fields chips (completeness) is essential to follow the dynamics of the disease and set priorities for intervention. The aim of this study was to evaluate the completeness of the notification forms of tuberculosis in the priority municipalities of Bahia (Camaçari , Feira de Santana , Ilhéus , Itabuna, Jequié, Lauro de Freitas , Porto Seguro , Teixeira de Freitas , Paulo Afonso, Barreiras and Salvador) to control the disease in individuals with HIV/AIDS using tabulations obtained from the Sinan in the period from 2001 to 2010. The results showed that despite the completeness of the field HIV be above 50 %, more than half the cases were met as "undone" or "being processed" in all municipalities assessed in the period. The low completeness of reporting forms may compromise the quality of surveillance of TB cases. The results suggest the need for greater availability of HIV testing in these individuals.

O controle da coinfecção HIV/Tuberculose (TB) ainda representa um desafio para a saúde pública. Ambas as doenças são de notificação obrigatória e o Sistema Nacional de Agravos de Notificação (SINAN) é o órgão responsável pela coleta e processamento das fichas individuais de notificação e acompanhamento. O preenchimento adequado dos campos destas fichas (completude) é essencial para acompanhar a dinâmica da doença e definir prioridades de intervenção. O objetivo deste estudo foi avaliar a completude das fichas de notificações de tuberculose nos municípios prioritários da Bahia (Camaçari, Feira de Santana, Ilhéus, Itabuna, Jequié, Lauro de Freitas, Porto Seguro, Teixeira de Freitas, Paulo Afonso, Barreiras e Salvador), para controle da doença em indivíduos com HIV/AIDS, através dos relatórios de tabulação do Sinan, no período de 2001 a 2010. Os resultados demonstraram que, apesar da completude do campo HIV estar acima de 50%, mais da metade das fichas estavam preenchidas como "não realizado" ou "em andamento", em todos os municípios avaliados no período. A baixa completude das fichas de notificação pode comprometer a qualidade de vigilância dos casos de TB. Os resultados sugerem a necessidade de maior disponibilidade de teste para HIV nesses indivíduos.

Gold/chemistry , Nanocomposites/chemistry , Spectrum Analysis, Raman , Silver/chemistry , Chlorides/chemistry , Electrochemical Techniques , Gold Compounds/chemistry , Microscopy, Electron, Transmission , Nanotechnology/instrumentation , Nanotechnology/methods , Oxidation-Reduction , Surface Properties , Spectrum Analysis, Raman/instrumentation , Spectrum Analysis, Raman/methods
Article in English | WPRIM | ID: wpr-89600


This study was performed to compare the 2 different portable devices measuring fractional exhaled nitric oxide (FeNO) and to see the correlation between FeNO and induced sputum eosinophil count (ISE). Forty consecutive subjects clinically suspected to have asthma underwent FeNO measurement by NIOX-MINO(R) and NObreath(R) concurrently. All also had induced sputum analysis, methacholine provocation test or bronchodilator response test, and spin prick test. Agreement between the 2 devices was evaluated. The correlation between FeNO and ISE was assessed, as well as the cut-off level of FeNO to identify ISE > or =3%. The intraclass correlation coefficient (ICC) between FeNO levels measured by NIOX-MINO(R) (FeNO(NIOX-MINO)) and NObreath(R) (FeNO(NObreath)) was 0.972 with 95% confidence interval of 0.948-0.985. The 95% limits of agreement were -28.9 to 19.9 ppb. The correlation coefficient between ISE and FeNO(NIOX-MINO) was 0.733 (P or =3% with 90% sensitivity and 81% specificity. Age, sex, body mass index, smoking history, atopy, and the presence of asthma did not affect the FeNO level and its correlation with ISE. The NIOX-MINO (R) and NObreath(R) agree with each other to a high degree. Both devices showed close correlation with ISE with similar cut-off value in identifying ISE > or =3%.

Asthma , Body Mass Index , Electrochemical Techniques , Eosinophils , Methacholine Chloride , Nitric Oxide , ROC Curve , Smoke , Smoking , Sputum
Bol. latinoam. Caribe plantas med. aromát ; 13(6): 527-536, nov.2014. ilus, tab
Article in English | LILACS | ID: lil-795823


The chemical constituents of the hexane and methanol extracts obtained from the branch bark of Bursera simaruba (Burseraceae) grown in Querétaro, Mexico, were investigated by GC-MS, HPLC coupled to DAD, and NMR techniques. Seventeen compounds, including terpenoids, flavonoids, phenolic acids, long-chain fatty acids (FA), methyl esters of FA and sucrose, were identified. In addition, an assessment of the antiradical activity of the methanol extract (ME) was also carried out using DPPH, ABTS, FRAP and DPV assays. The DPPH, ABTS and FRAP assays showed a low antioxidant capacity for the ME. This was in accordance with the relatively low quantities of phenols found in the extract. However, according to the differential pulse voltammetry assay (DVP), this extract exhibited an oxidation potential close to those of quercetin and (+)-catechin, two of the flavonoids with recognized good antioxidant power. This indicated that the ME does contain compounds with good antioxidant capacity and suggested that sometimes the most popular methods commonly used might be underestimating the true antioxidant capacities of plant samples and how the DPV is a valuable complementary tool to be taken into consideration when conducting these in vitro assays...

Los constituyentes químicos de los extractos hexánicos y metanólicos de la corteza de ramas de Bursera simaruba (Burseraceae) recolectada en Querétaro, México, fueron investigados mediante las Cromatografías de Gases acoplada a Espectrometría de masas (GC-MS) y de líquidos de alta resolución (HPLC) acoplada a un detector de arreglo de diodos (DAD) (HPLC-DAD) y mediante RMN. Diecisiete compuestos, incluyendo terpenos, flavonoides, ácidos fenólicos, ácidos grasos de cadena larga (AG), ésteres metílicos de AG y la sacarosa fueron identificados. De manera adicional, se determinó la actividad antioxidante del extracto metanólico utilizando los ensayos de DPPH, ABTS, FRAP y DPV (Voltametría de Pulso Diferencial). Los métodos de DPPH, ABTS y FRAP indicaron una baja capacidad antioxidante para este extracto. Esta observación estuvo de acuerdo con las bajas cantidades de fenólicos encontrados en este extracto. Sin embargo, mediante el método DPV, el extracto tuvo un potencial de oxidación cercano a los de la quercetina y la (+)-catequina, dos de los flavonoides con reconocida buna capacidad antioxidante. Estos resultados indican que el extracto sí contiene metabolitos secundarios con buena capacidad antioxidante y sugieren además que los métodos más comunes pueden subestimar la verdadera capacidad antioxidante de extractos de plantas y resalta la importancia del método DPV como complementario a tener en cuenta en estos tipos de estudios in vitro...

Humans , Antioxidants/pharmacology , Bursera/chemistry , Plant Extracts/pharmacology , Plant Extracts/chemistry , Antioxidants/chemistry , Chromatography, High Pressure Liquid , Electrochemical Techniques , Phenols/analysis , Gas Chromatography-Mass Spectrometry , Terpenes/analysis
Electron. j. biotechnol ; 17(4): 183-188, July 2014. ilus, graf, tab
Article in English | LILACS | ID: lil-719110


Background A simple, rapid, low-cost and environmentally friendly method was developed to determine dopamine (DA) in the presence of ascorbic (AA) and uric acid (UA) based on a novel technique to prepare a graphene-chitosan (GR-CS) nanocomposite and modify it on the surface of carbon paste electrode (CPE). For our design, CS acts as a media to disperse and stabilize GR, and then GR plays a key role to selective and sensitive determination of DA. Results Under physiological conditions, the linear range for dopamine was determined from 1 × 10- 4 to 2 × 10- 7 mol/L with a good correlation coefficient of 0.9961 in the presence of 1000-fold interference of AA and UA. The detection limit was estimated to be 9.82 × 10- 8 mol/L (S/N = 3). In order to study the stability and reproducibility, GR/CS/CPE underwent successive measurements in 10 times and then tested once a d for 30 d. The result exhibited 98.25% and 91.62% activities compared with the original peak current after 10-time measurements and 30-d storage. Conclusion The GR/CS/CPE has wide linear concentration range, low detection limit, and good reproducibility and stability, which suggests that our investigations provide a promising alternative for clinic DA determination.

Carbon/chemistry , Dopamine/analysis , Chitosan/chemistry , Graphite/chemistry , Electrodes , Nanocomposites/chemistry , Electrochemical Techniques , Limit of Detection , Chemistry Techniques, Synthetic , Hydrogen-Ion Concentration