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1.
Mikrochim Acta ; 187(2): 142, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31965326

RESUMO

A sol-gel method is presented to synthesize molecularly imprinted polymers (MIPs) composed with a copper-based metal-organic framework (referred to as MIP/HKUST-1) on a paper support to selectively recognize tetrabromobisphenol A (TBBPA). The imprinting factor is 7.6 and the maximum adsorption capacity is 187.3 mg g-1. This is much better than data for other MIPs. The degradation of TBBPA is introduced in the procedure. Due to the selective recognition by the MIP, the enzyme-mimicking properties of HKUST-1 under the MIP layer became weak due to the decrease of residue imprinted cavities. And adsorbed TBBPA can be degraded under consumption of hydrogen peroxide (H2O2). The combined effect of H2O2 and HKUST-1 cause the coloration caused by catalytic oxidation of 3,3',5,5'-tetramethylbenzidine to become less distinct. This amplification strategy is used for the ultrasensitive and highly selective colorimetric determination of TBBPA. The gray intensity is proportional to the logarithm concentration of TBBPA in the range of 0.01-10 ng g-1. The limit of detection is as low as 3 pg g-1, and the blank intensities caused by TBBPA analogues are <1% of that caused by TBBPA at the same concentration, this implying excellent selectivity. The spiked recoveries ranged from 94.4 to 106.6% with relative standard deviation values that were no more than 8.6%. Other features include low costs, rapid response, easy operation and on-site testing. Graphical abstractSchematic representation of colorimetric determination of tetrabromobisphenol A (TBBPA) by paper-based metal-organic framework-based molecularly imprinted polymers (MIP/HKUST-1 composites) using 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate.

2.
J Ethnopharmacol ; 246: 112225, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509781

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Our previous research found that Sangguayin (SGY) deccoction made by four dietary and medicinal plant components (Leaf of Morus alba L., Root of Pueraria lobata (Willd.) Ohwi., Root of Dioscorea opposita Thunb. and Fruit of Momordica charantia L.) showed significant anti-diabetic effects on db/db mice and high fat diet induced obese mice. Nevertheless, it remained unclear what the role of gut microbiota in the hypoglycaemia effects of SGY. AIMS OF THE STUDY: This study aimed to examine the beneficial effects of Sangguayin Deccoction against metabolic syndrome and and its regulating role in gut microbiota and hepatic metabolome. MATERIALS AND METHODS: C57BL/6J mice were divided to a normal chow diet (NCD), high-fat diet (HFD), and high-fat diet with Sangguayin Decoction (HFD-SGY, oral dose of 250 mg/kg/d) for 16 weeks. Next generation sequencing was applied for analyzing the gut microbial community of colonic contents. Further, untargeted metabolomic analysis based on LC-MS was used for determining the changes of hepatic metabolites. Hepatic genes expression were measured by quantitative PCR. RESULTS: SGY supplement decreased blood glucose level and glucose intolerance. Illumina MiSeq sequencing revealed that SGY increased Verrucomicrobia phylum, resulting in a bloom of Akkermansia, and eventually upregulated the contents of Lachoclostridium and Roseburia. Additionally, dietary SGY decreased bacteria including Faecalibaculum, and Blautia. Moreover, the hepatic lipid metabolism was notably altered by SGY treatment. The oxidation of glutamione metabolism idecreasees, production of poly-unsaturated fatty acid (PUFA) got significant increase in liver tissue. The reversion of PUFA metabolism by SGY may act through PPARα mediated Fads1 and Fads2 gene expression. The altered metabolites in liver showed intimate correlatship with modified genera. CONCLUSION: Data indicated that SGY reshaped gut microbial structure and improved PUFA metabolism. These functions of SGY may alter hepatic lipid metabolism, conferring preventative effects against high-fat diet induced metabolic syndrome.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Obesidade/induzido quimicamente , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Dieta Hiperlipídica , Medicamentos de Ervas Chinesas/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fitoterapia , Extratos Vegetais/química
3.
Sci Total Environ ; 706: 135961, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31841851

RESUMO

Personal care and cosmetic products (PCPs) are the primary exposure pathway of humans to parabens and their safety has become a public concern. However, sample pretreatment of PCPs is a great challenge due to their complexities and diversity. In this study, epoxide modified molecularly imprinted polymers (MIPs) were synthesized using ethylparaben as a template, methacrylic acid and isobutyl vinyl ether as co-monomers and glycidilmethacrylate as a post-modified monomer. MIP layer open-tubular tubes were prepared by modifying branched polyethylenimine and then grafting MIPs onto the inner surface of Teflon capillary tubes. The tube was coiled to effectively increase mass transfer and coupled to an HPLC-UV system for parabens detection in PCPs. Matrix interference was significantly decreased while efficient enrichment and recoveries were obtained. Under optimized conditions, the linear range for parabens detection was 0.5-600 ng mL-1 with detection limits of 0.2 to 0.3 ng mL-1. The system was used to study the contents of parabens in popular PCPs. The concentrations of parabens in 108 PCPs ranged from <0.5 ng g-1 to 2856 µg g-1 with geometric mean of 250.3 µg g-1. Almost all of the products contained at least one kind of parabens; methyl paraben (geometric mean: 182.9 µg g-1) and n-propyl paraben (geometric mean: 42.5 µg g-1) were the predominant compounds had been found in the samples. This method could be useful for human exposure assessment towards parabens.


Assuntos
Cosméticos , Cromatografia Líquida de Alta Pressão , Impressão Molecular , Parabenos , Polímeros
4.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1126-1127: 121708, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31437773

RESUMO

Analysis of acidic pharmaceuticals in complex biological samples is a challenging and formidable task due to the existence of interfering constituents within the sample matrices. Therefore, in order to avoid analytical column clogging and suppression/enhancement of signals of the analyte of interest, herein a simple, cost-effective and quick online ion chromatography based clean-up setup was introduced. This system was further coupled with a cost-effective homemade photochemically induced fluorimetric (PIF) setup for direct online conversion of non-fluorescent acidic pharmaceutical drugs into their respective fluorescent species. This advantageous system was favorably applied for the determination of four non-fluorescent acidic compounds in two complex biological samples (human serum and oral fluid) with minimum labor and organic solvent consumption. At optimized conditions, the developed method has shown good sensitivity, selectivity, satisfactory recoveries (88.68-102.14%) and low limits of detection (0.35-8.10 µg/L) with minimum or zero matrix effect.


Assuntos
Cromatografia por Troca Iônica/métodos , Fluorometria/métodos , Preparações Farmacêuticas/análise , Ácidos/análise , Ácidos/sangue , Ácidos/química , Corantes Fluorescentes/química , Humanos , Limite de Detecção , Modelos Lineares , Preparações Farmacêuticas/sangue , Preparações Farmacêuticas/química , Reprodutibilidade dos Testes , Saliva/química
5.
J Sep Sci ; 41(22): 4096-4104, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30230241

RESUMO

A simple, cost-effective, sensitive, and quick method for the determination of nitenpyram and its metabolite 6-chloronicotinic acid in environmental samples was developed by coupling an ion chromatograph with a fluorescence detector and a post-column photochemical reactor. This developed analytical method involved a rapid sample extraction by modified and miniaturized quick, easy, cheap, effective, rugged, and safe method followed by isocratic ion chromatographic separation of nitenpyram and 6-chloronicotinic acid into an IonPac™ AS11-HC column protected by IonPac™ AG11A guard column by running 30 mM NaOH + 10% acetonitrile mobile phase. A homemade post-column photochemical reactor was also integrated with the ion chromatographic system for online transformation of both analytes into their respective highly fluorescent photoproduct in basic media without using an extra pump. The developed method was validated by following SANTE/11945/2015 guidelines on analytical quality control and validation procedures. The method showed a good linear response (r > 0.999), improved limit of detection (0.101-0.132 µg/L), minimum or no matrix effect, excellent recoveries (90.2-100.10%) and relative standard deviations were found to be ≤6.50%.


Assuntos
Poluentes Ambientais/química , Neonicotinoides/análise , Ácidos Nicotínicos/análise , Cromatografia por Troca Iônica , Monitoramento Ambiental , Estrutura Molecular , Processos Fotoquímicos , Espectrometria de Fluorescência
6.
Sci Rep ; 8(1): 12327, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-30120273

RESUMO

Nowadays, there are rising concerns about the extensive use of the antibiotics such as chloramphenicol (CAP), has threatened the human life in the form of various vicious diseases. The limited selectivity and sensitivity of confirmatory techniques (UV and electrochemical) and non-fluorescence property of CAP make its determination a challenging task in the modern pharmaceutical analysis. In order to redeem the selective, sensitive and cost-effective fluorescence methodology, here by the dual role of synthesized porous SnO2 nanoparticles were exploited; (i) a porous sorbent in a µ-QuEChERS based sample preparation and as (ii) a stimulant for the transformation of non-fluorescent analytes namely CAP and p-nitrophenol (p-NP) into their respective fluorescent product. We report a green, simple, selective and cost effective ion chromatographic method for CAP sensitive determination in three complex matrices including milk, human urine and serum. The synthesized sorbent not only selectively adsorbed and degraded the matrix/interferences but also selectively reduced the non-fluorescent antibiotic CAP into a fluorescent species. This developed ion chromatographic method exhibited good selectivity, linearity (r2 ≥ 0.996) and limit of detection (LOD) was in the range 0.0201-0.0280 µg/kg. The inter- and intraday precisions were also satisfactory having a relative standard deviation (RSDs) less than 14.96% and excellent recoveries of CAP in the range of 78.3-100.2% were retrieved in various complex samples.


Assuntos
Antibacterianos/análise , Cloranfenicol/análise , Cromatografia por Troca Iônica , Nanopartículas/química , Animais , Humanos , Limite de Detecção , Metabolômica/métodos , Leite/química , Porosidade , Reprodutibilidade dos Testes
7.
Blood Coagul Fibrinolysis ; 26(5): 564-71, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25828970

RESUMO

The aim of this study was to investigate causative mutations of two unrelated symptomatic Chinese children with dysfibrinogenemia and their family members.Fibrinogen genes, including FGA, FGB and FGG of all participants were PCR-amplified, followed by direct sequencing. Precipitated plasma fibrinogen of some family members was analyzed by western blotting, fibrin polymerization and scanning electron microscopy (SEM).Proband 1 associated with frequent epistaxis was identified to harbor a heterozygous Arg275Cys mutation in FGG, along with a polymorphism Arg448Lys in FGB. Proband 2 with apparently prolonged thrombin time and very low functional fibrinogen had undergone both spontaneous intracranial hemorrhages and deep venous thrombosis. Sequencing of all proximal promoters, coding regions, introns and 3'-untranslated region using genomic DNA of Proband 2 yielded no mutation in three fibrinogen genes. Western blotting of this patient's precipitated plasma fibrinogen detected no truncated protein. Fibrinogen polymerization curve showed prolonged lag phase and severely decreased final turbidity, and SEM observations of fibrin clots made from Proband 2 revealed an abnormal sponge-like mass with large pores. We speculate that other underlying mechanisms responsible for dysfibrinogenemia such as abnormal posttranscriptional processing or posttranslational modification, which are independent of detectable mutations in the genomic DNA sequence, may exist.


Assuntos
Afibrinogenemia/genética , Fibrinogênio/genética , Grupo com Ancestrais do Continente Asiático , Pré-Escolar , Humanos , Masculino , Mutação
8.
J Cell Mol Med ; 18(7): 1334-43, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24758696

RESUMO

Beta-adrenoceptor (ß-AR) exerts critical regulation of cardiac function. MicroRNAs (miRNAs) are potentially involved in a variety of biological and pathological processes. This study aimed to investigate the role of miRNA let-7e in the up-regulation of ß(1) -AR and arrhythmogenesis in acute myocardial infarction (AMI) in rats. ß(1) -AR expression was significantly up-regulated and let-7a, c, d, e and i were markedly down-regulated in the infarcted heart after 6 and 24 hrs myocardial infarction. Forced expression of let-7e suppressed ß(1) -AR expression at the protein level, without affecting ß(1) -AR mRNA level, in neonatal rat ventricular cells (NRVCs). Silencing of let-7e by let-7e antisense inhibitor (AMO-let-7e) enhanced ß(1) -AR expression at the protein level in NRVCs. Administration of the lentivirus vector containing precursor let-7e (len-pre-let-7e) significantly inhibited ß(1) -AR expression in rats, whereas len-AMO-let-7e up-regulated ß(1) -AR relative to the baseline control level, presumably as a result of depression of tonic inhibition of ß(1) -AR by endogenous let-7e. Len-negative control (len-NC) did not produce significant influence on ß(1) -AR expression. Len-pre-let-7e also profoundly reduced the up-regulation of ß(1) -AR induced by AMI and this effect was abolished by len-AMO-let-7e. Importantly, len-pre-let-7e application significantly reduced arrhythmia incidence after AMI in rats and its anti-arrhythmic effect was cancelled by len-AMO-let-7e. Notably, anti-arrhythmic efficacy of len-pre-let-7e was similar to propranolol, a non-selective ß-AR blocker and metoprolol, a selective ß(1) -AR blocker. Down-regulation of let-7e contributes to the adverse increase in ß(1) -AR expression in AMI and let-7e supplement may be a new therapeutic approach for preventing adverse ß(1) -AR up-regulation and treating AMI-induced arrhythmia.


Assuntos
Antiarrítmicos , Arritmias Cardíacas/prevenção & controle , MicroRNAs/genética , Infarto do Miocárdio/prevenção & controle , Miócitos Cardíacos/metabolismo , Receptores Adrenérgicos beta 1/química , Regiões 3' não Traduzidas/genética , Animais , Arritmias Cardíacas/genética , Arritmias Cardíacas/patologia , Biomarcadores/análise , Western Blotting , Células Cultivadas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Frequência Cardíaca , Masculino , Infarto do Miocárdio/genética , Infarto do Miocárdio/patologia , Miócitos Cardíacos/patologia , RNA Mensageiro/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Receptores Adrenérgicos beta 1/genética , Receptores Adrenérgicos beta 1/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Cell Physiol Biochem ; 32(6): 1818-29, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24356076

RESUMO

BACKGROUND: Arsenic trioxide (As2O3), an ancient drug used in traditional Chinese medicine, has substantial anticancer activities, especially in the treatment of patients suffering from acute promyelocytic leukemia (APL); however the underlying mechanisms are not well understood. METHODS: MTT assay was used to detect the cell viability. Flow Cytometry analysis and caspase-3 activity assay were used to measure apoptosis of APL cells. Caspase-3 and Bax levels were analyzed by western blot and let-7d and miR-766 levels were determined by real-time RT-PCR. RESULTS: As2O3 significantly inhibited cell viability and induced apoptosis in APL cells. Several microRNAs, including let-7d and miR-766, were dysregulated in APL cells treated with As2O3. The expression of caspase-3 and Bax, which are targets of let-7d and miR-766, respectively, were up-regulated in As2O3 treated cells. Transfection of let-7d and miR-766 into NB4 cells decreased the expression of caspase-3 and Bax, respectively. Correspondingly, transfection of these microRNAs increased NB4 cell viability. As2O3 induced degradation of promyelocytic leukemia (PML), and then induced the down-regulation of both let-7d and miR-766 in NB4 cells. CONCLUSIONS: We construct a dysregulated microRNA network involved in As2O3-induced apoptosis in APL. Targeting this network may be a new strategy for the prevention of side effects associated with APL treatment with As2O3.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Arsenicais/farmacologia , MicroRNAs/metabolismo , Óxidos/farmacologia , Regiões 3' não Traduzidas , Trióxido de Arsênio , Sequência de Bases , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Células HL-60 , Humanos , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Regulação para Cima/efeitos dos fármacos , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
10.
J AOAC Int ; 96(1): 1-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23513948

RESUMO

The systemicity of chlorantraniliprole was investigated and evidence was collected for formulating strategies in controlling vegetable or rice pests. Systemicity of chlorantraniliprole was investigated through chlorantraniliprole application on velvetleaf (Abutilon theophrasti) leaves as well as through hydroponic experiments. The roots of velvetleaf were incubated in chlorantraniliprole solution with a concentration of 50 microg/mL; the concentrations of chlorantraniliprole in xylem above the solution parts were 3.14, 5.67, and 6.89 microg/g at 24, 48, and 72 h after treatment. When the roots were incubated in chlorantraniliprole solution with a concentration of 200 microg/mL, the concentrations of chlorantraniliprole in xylem above the solution reached 6.48, 8.76, and 10.55 microg/g at 24, 48, and 72 h after treatment. Chlorantraniliprole was not detected in the phloem above the solution after these two treatments. When chlorantraniliprole solution with a concentration of 100 microg/mL was applied on mature leaves, chlorantraniliprole was found in xylem above the mature leaves at concentrations of 0.55, 0.74, and 0.92 microg/g at 24, 48, and 72 h after the treatment. No chlorantraniliprole was detected in the leaves below the mature leaves or the phloem above them. When chlorantraniliprole solution with a concentration of 100 microg/mL was applied on apical leaves, no chlorantraniliprole was detected in the xylem or phloem below them. These results indicated that chlorantraniliprole can be transported through xylem only upward, but chlorantraniliprole has no phloem mobility in velvetleaf.


Assuntos
Inseticidas/análise , Malvaceae/química , ortoaminobenzoatos/análise , Cromatografia Líquida de Alta Pressão , Floema/química , Espectrometria de Massas em Tandem , Xilema/química
11.
Bull Environ Contam Toxicol ; 89(5): 1021-6, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22983724

RESUMO

Flubendiamide, which belongs to the new chemical class of phthalic acid diamides, is widely used against lepidopteron pests in a variety of vegetable and rice pests. It provides superior plant protection against a broad range of economically important lepidopterous pests, including Spodoptera exigua and Plutella xylostella. A determination method of flubendiamide in the cabbage was established in this paper. Flubendiamide in the cabbage was extracted with acetonitrile and ultrasonic extraction, and was purified by QuEChERS and analyzed by LC-MS/MS (liquid chromatography-tandem mass spectrometry). The results indicated that the average recovery of flubendiamide in the cabbage was 81.27%-91.45%, the coefficient of variation was 1.79%-4.81%, and the lowest detection concentration was 0.3 µg/kg. The extraction of flubendiamide from the cabbage and its analysis was in accordance with the pesticide residue criterion, i.e., simple, rapid, accurate, reproducible, stable, separatory, and convenient. It identifies and quantifies trace-level flubendiamide residues in the cabbage extracts using LC-MS/MS in the ESI negative mode coupled with the QuEChERS method.


Assuntos
Benzamidas/análise , Brassica/química , Contaminação de Alimentos/análise , Inseticidas/análise , Resíduos de Praguicidas/análise , Sulfonas/análise , Cromatografia Líquida , Espectrometria de Massas em Tandem
12.
Neurosci Lett ; 457(1): 45-8, 2009 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-19429159

RESUMO

Superior response inhibition is an essential component of the advanced cognitive abilities of gifted children. This study investigated response inhibition in intellectually gifted children by recording event-related brain potentials (ERPs) during a Go/NoGo task. Fifteen intellectually gifted children and 15 intellectually average children participated. Our present findings showed that intellectually gifted children had shorter Go-P3 latency, indicating faster processing of Go stimuli, a finding consistent with previous studies. We focused on the two inhibition-related components, NoGo-N2 and NoGo-P3. The results showed that NoGo-P3 latency was shorter for intellectually gifted children compared to their average peers. N2 latency did not indicate the intelligence difference. These results suggested that intellectually gifted children showed faster inhibition when dealing with NoGo stimuli, and this superiority came from the later stages of inhibition, i.e., response evaluation or the success of inhibiting a response, as indexed by the shorter P3 latency.


Assuntos
Desenvolvimento Infantil/fisiologia , Criança Superdotada , Comportamento de Escolha/fisiologia , Potenciais Evocados Visuais/fisiologia , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Mapeamento Encefálico , Criança , Eletroencefalografia/métodos , Feminino , Humanos , Modelos Lineares , Masculino , Estatística como Assunto
13.
Electrophoresis ; 28(22): 4091-100, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17960537

RESUMO

A quaternary ammonium chitosan, 2-hydroxypropyltrimethylammonium chloride chitosan (HACC), has been developed for the dynamic coating material in CE for the first time. It presented many advantages such as favorable water solubility, satisfactory coating efficiency, and EOF toward the anode at pH >7.0. Using the modified fused-silica capillary, sulfonamides (SAs), an important group of veterinary drugs, were separated and detected by CE combined with field-amplified sample injection (FASI). The LODs of sulfonamides with UV detection were less than 0.5 ng/mL. The proposed method has been applied to the determination of veterinary sulfonamide residues in samples such as chicken, beef, and honey with fast separation (15 sulfonamides within 20 min), low LODs (0.1-0.5 ng/mL), and good reliability compared to the criteria of China (GB/T 18932.17-2003).


Assuntos
Quitosana , Eletroforese Capilar/métodos , Sulfonamidas/isolamento & purificação , Drogas Veterinárias/isolamento & purificação , Animais , Eletroforese Capilar/instrumentação , Eletroforese Capilar/normas , Compostos de Amônio Quaternário
14.
J Chromatogr A ; 1118(1): 155-9, 2006 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-16516904

RESUMO

Simple, reliable and sensitive analytical methods to determine the anions, such as fluoride, monofluorophaosphate, glycerophosphate related to anticaries are necessary for basic investigations of anticaries and quality control of dentifrices. A method for the simultaneous determination of organic acids, organic anions and inorganic anions in the sample of commercial toothpaste is proposed. Nine anions (fluoride, chloride, nitrite, nitrate, sulfate, phosphate, monofluorophaosphate, glycerophosphate and oxalic acid) were analyzed by means of ion chromatography using a gradient elution with KOH as mobile phase, IonPac AS18 as the separation column and suppressed conductivity detection. Optimized analytical conditions were further validated in terms of accuracy, precision and total uncertainty and the results showed the reliability of the IC method. The relative standard deviations (RSD) of the retention time and peak area of all species were less than 0.170 and 1.800%, respectively. The correlation coefficients for target analytes ranged from 0.9985 to 0.9996. The detection limit (signal to noise ratio of 3:1) of this method was at low ppb level (<15 ppb). The spiked recoveries for the anions were 96-103%. The method was applied to toothpaste without interferences.


Assuntos
Ânions/análise , Cromatografia por Troca Iônica/métodos , Dentifrícios/química , Glicerofosfatos/análise , Cloretos/análise , Fluoretos/análise , Nitratos/análise , Nitritos/análise , Ácido Oxálico/análise , Fosfatos/análise , Reprodutibilidade dos Testes , Sulfatos/análise , Cremes Dentais/química
15.
J Chromatogr A ; 1118(1): 68-72, 2006 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-16483592

RESUMO

A single-column method for the simultaneous determination of common cations and transition metals in real samples is proposed in this paper. Eleven cations (copper, lithium, sodium, ammonium, potassium, cobalt, nickel, magnesium, calcium, strontium and zinc) were separated and analyzed by means of ion chromatography using an isocratic elution with 2.5 mM methane sulfonic acid and 0.8 mM oxalic acid as mobile phase, IonPac SCS1 (250 mm x 4 mm I.D.) as the separation column and non-suppressed conductor detection. Optimized analytical conditions were further validated in terms of accuracy, precision and total uncertainty and the results showed the reliability of the IC method. The relative standard deviations (RSDs) of the retention time and peak area were less than 0.04 and 1.30%, respectively. The coefficients of determination for cations ranged from 0.9988 to 1.000. The method developed was successfully applied to determination of cations in samples of beer and bottled mineral water. The spiked recoveries for the cations were 94-106%. The method was applied to beer and beverage without interferences.


Assuntos
Cátions/análise , Cromatografia por Troca Iônica/métodos , Metais/análise , Cátions/química , Metais/química , Águas Minerais/análise , Ácido Oxálico/química , Padrões de Referência , Reprodutibilidade dos Testes , Ácidos Sulfônicos/química
16.
Life Sci ; 77(17): 2098-110, 2005 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-15978626

RESUMO

Selenium (Se) plays an important role in cancer-prevention. Silkworm pupas have been used as a Chinese traditional medicine since ancient time. In order to find effective carcinostatic agents, Se-rich amino acids were extracted from Ziyang silkworm pupas. The Se content of Ziyang pupas was measured to be 215 times higher than that of Luoyang normal ones, and the majority of Se was stored in proteins. Composition analysis showed that Se-rich amino acids from Ziyang pupas had higher amounts of selenomethionine, methionine, cystine, and tyrosine than normal amino acids from Luoyang pupas which were rich in amino acids containing alkyl side chains. When cultured with human hepatoma cells SMMC-7721, Se-rich amino acids at concentrations of 0.5, 1.5, and 2.5 micromol L(-1) Se significantly and dose-dependently inhibited cell viability, induced changes in cell morphology and cycle, and caused cell apoptosis. On the contrary, normal amino acids did not show any inhibitory effect on SMMC-7721 cells. Sodium selenite or selenomethionine at the same Se concentrations only slightly inhibited the hepatoma cells. Mechanism study showed that selenium-rich amino acids could increase the generation of intracellular reactive oxygen species (ROS) concentration-dependently. Antioxidant N-acetylcyteine partially inhibited the increase of ROS. Those results suggested that Se-rich amino acids were effective carcinostatic agents compared with sodium selenite and selenomethionine. The mechanism for their hepatoma-inhibitory effects was the induction of cellular apoptosis through ROS generation.


Assuntos
Aminoácidos/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Bombyx/química , Compostos Organosselênicos/farmacologia , Aminoácidos/isolamento & purificação , Animais , Antineoplásicos/isolamento & purificação , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Citometria de Fluxo , Humanos , Compostos Organosselênicos/isolamento & purificação , Pupa/química , Espécies Reativas de Oxigênio/metabolismo
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