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1.
Genet Mol Res ; 16(3)2017 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-28873200

RESUMO

As a ß2 integrin family member, Mac-1 plays an important role in the inflammatory response. Inflammation and lung injury are closely associated, but the involvement of Mac-1 in the occurrence and development of such pathologies remains poorly understood. We aimed to investigate the relationship between Mac-1 deficiency and respiratory failure in Mac-1 knockout {Mac-1-/-} mice, using C57BL/6J mice as a control. The newborn survival rate of Mac-1-/- mice was calculated, and mouse lung tissue was treated with hematoxylin and eosin and subjected to immunofluorescent staining. Moreover, western blotting and immunohistochemistry were used to detect the expression of molecules specific to type I and type II alveolar epithelial cells, as well as alveolar surfactant proteins secreted by the latter. Survival of Mac-1-/- pups was significantly lower than that of newborn C57BL/6J mice. In a float test, lung tissues from C57BL/6J mice were buoyant, whereas those of Mac-1-/- mice were not. Compared with C57BL/6J mice, expression of proSP-C {specific to type II alveolar epithelial cells} and alveolar surfactant proteins in Mac-1-/- mice was not significantly different, implying that type II cell function was unaltered. However, western blotting revealed expression of T1α, Aqp5, and Snx5 {type I alveolar epithelial cell markers} in Mac-1-/- mice to be significantly decreased {P < 0.05}. In conclusion, Mac-1 may play an important role in respiratory failure. Its absence leads to this condition not by influencing type II alveolar epithelial cells or their secreted surfactant proteins, but rather by reducing type I alveolar cell numbers.


Assuntos
Células Epiteliais Alveolares/metabolismo , Antígeno CD11b/genética , Insuficiência Respiratória/metabolismo , Animais , Antígeno CD11b/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas a Surfactantes Pulmonares/genética , Proteínas Associadas a Surfactantes Pulmonares/metabolismo , Insuficiência Respiratória/genética , Insuficiência Respiratória/patologia
2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 50(4): 357-61, 2016 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-27029369

RESUMO

OBJECTIVE: To develop an ultra-high performance liquid chromatography mass spectrometer method for the rapid determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urines. METHODS: 8-OHdG standard solution with the concentration from 0.01 to 0.1 µg/ml was formulated. The solution was implanted into ion source with a rate of 7 µl/min, the mass-to-charge ratio of parent ion and product ions, and ion mass to charge ratio was identified. The mass spectrum parameters of each Ion pairs, such as DP, EP and EXP, were gradually optimized. The urine sample with a concentration of 10.0 µg/L was detected, and the pH of the sample was adjusted using 1 mol/L ammonium formate and formic acid solution with a volume ratio of 5∶1, 4∶1, 3∶1, 2∶1, and 1∶1. It was tested using three different polarity of SPE, i.e.: HLB, MCX, and MAX. The elution effect of methanol and water mixture with the proportion of 90∶10, 80∶20, 50: 50, 20: 80, and 10: 90 were tested, and then acetonitrile and water mixture with the proportion of 90∶10, 80∶20, 50∶50, 20∶80, 10∶90 were also tested. The standard curve was constructed using the ratio of a standard series application fluid concentration to corresponding compounds quantitative ion liquid concentration of the peak area. The detection limit was determined as 3 times of the signal to noise ratio corresponding to the concentration of 8-OHdG, and the quantitative lower limit was determined as 10 times of the signal to noise ratio corresponding to the concentration of 8-OHdG. The blank urine spiked recovery method was used to evaluate the precision and recovery rate. RESULTS: The mass to charge ratio of parent ion was 284.1 and the product ions was 168.1, 140.1, 123.0, and 112.0, respectively. The collision voltage of quantitative ion-pair 284.1/168.1 was 18 V, the 284.1/140.1 collision voltage was 42 V, the 284.1/123.0 collision voltage was 48 V, and the 284.1/112.0 collision voltage was 53 V. The recovery rate was the highest (87.9%-104.3%) when the pH of urine was adjusted by a 10 ml 1 mol/L ammonium formate solution, 2 ml of formic acid, 88 ml of water are mixed with the sample solution volume ratio of 1∶5, and then purified with 3 ml of methanol and 3 ml water activated HLB extraction column. Within 1.0-100.0 µg/L concentration range, 8-OHdG standard application solution test results showed a good linear relationship. The regression equation was y= 1.25x+0.74, and the correlation coefficient was r=0.999 5. The detection limit was 0.2 µg/L, and the limit of quantification was 0.7 µg/L. The method of recovery rate was in the range of 87.9% to 104.3%, the precision was in the range from 1.5% to 3.7% and inter-assay precision was in the range from 1.6% to 5.4%. CONCLUSION: The method developed in this study had high sensitivity, good precision and accuracy, and a wide range of testing concentrations.


Assuntos
Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Desoxiguanosina/análogos & derivados , Espectrometria de Massas , 8-Hidroxi-2'-Desoxiguanosina , Acetonitrilas , Desoxiguanosina/análise , Desoxiguanosina/urina , Humanos , Limite de Detecção
3.
Cell Death Dis ; 5: e1542, 2014 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-25429619

RESUMO

Reactive oxygen species (ROS) have an important role in regulating various cellular processes. Our previous study confirmed that selenite, an anti-tumour agent, triggered apoptosis through the production of ROS in multiple types of cancer cells. In this study, we discovered that ROS also inhibited protective autophagy by decreasing the expression of ULK1, an initiator of autophagy, in selenite-treated NB4 cells. Further experiments demonstrated that p-p53 (S392), a phosphorylation event promoted by p70S6K, bound to the promoter of ULK1 and modulated its expression. Experiments in a mouse tumour model with NB4 cells provided in vivo confirmation of the alterations in the p70S6K/p53/ULK1 axis. Collectively, our results show that ROS inhibited autophagy by downregulating the p70S6K/p53/ULK1 axis in selenite-treated NB4 cells.


Assuntos
Autofagia/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ácido Selenioso/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/efeitos dos fármacos , Proteína Homóloga à Proteína-1 Relacionada à Autofagia , Linhagem Celular Tumoral , Humanos , Camundongos , Modelos Biológicos , Fosforilação/efeitos dos fármacos , Fosfosserina/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Transdução de Sinais/efeitos dos fármacos
4.
Cell Death Dis ; 5: e1085, 2014 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-24577083

RESUMO

Inhibitor-of-apoptosis protein (IAP) inhibitors have been reported to synergistically reduce cell viability in combination with a variety of chemotherapeutic drugs via targeted cellular IAP (cIAP) depletion. Here, we found that cIAP silencing sensitised colorectal cancer (CRC) cells to selenite-induced apoptosis. Upon selenite treatment, the K63-linked ubiquitin chains on receptor-interacting protein 1 (RIP1) were removed, leading to the formation of the death-inducing complex and subsequent caspase-8 activation. Although the ubiquitinases cIAP1 and cIAP2 were significantly downregulated after a 24-h selenite treatment, cylindromatosis (CYLD) deubiquitinase protein levels were marginally upregulated. Chromatin immunoprecipitation assays revealed that lymphoid enhancer factor-1 (LEF1) dissociated from the CYLD promoter upon selenite treatment, thus abolishing suppression of CYLD gene expression. We corroborated these findings in a CRC xenograft animal model using immunohistochemistry. Collectively, our findings demonstrate that selenite caused CYLD upregulation via LEF1 and cIAP downregulation, both of which contribute to the degradation of ubiquitin chains on RIP1 and subsequent caspase-8 activation and apoptosis. Importantly, our results identify a LEF1-binding site in the CYLD promoter as a potential target for combinational therapy as an alternative to cIAPs.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Proteínas Inibidoras de Apoptose/metabolismo , Fator 1 de Ligação ao Facilitador Linfoide/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteínas de Ligação a RNA/metabolismo , Ácido Selenioso/farmacologia , Proteínas Supressoras de Tumor/metabolismo , Animais , Proteína 3 com Repetições IAP de Baculovírus , Sítios de Ligação , Caspase 8/genética , Caspase 8/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Enzima Desubiquitinante CYLD , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Proteínas Inibidoras de Apoptose/genética , Fator 1 de Ligação ao Facilitador Linfoide/genética , Camundongos , Camundongos Nus , Regiões Promotoras Genéticas , Interferência de RNA , Transdução de Sinais , Fatores de Tempo , Transfecção , Carga Tumoral/efeitos dos fármacos , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases , Ubiquitinação , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Cell Death Dis ; 5: e1071, 2014 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-24556686

RESUMO

Survivin-2B, a known splice variant of survivin, has been reported to promote cell death in some cancer cells, although it keeps prosurvival function in others, and the mechanisms are unclear. In this report, we discovered that selenite, an antitumor agent, switched protective autophagy to apoptosis in NB4 cells. In this process, the level of survivin-2B was decreased and the interaction between IKK alpha and survivin-2B in the nucleus was attenuated, which further led to the decrease of nuclear IKK alpha. As a result, P73, a known transcript factor of UVRAG, was downregulated. Therefore, the expression of UVRAG, one of the initiators of autophagy, was inhibited. The regulatory status of survivin-2B was also proved in NB4 cells after different chemicals' exposure and in other tumor cell lines (Jurkat, HCT116). Finally, experiments in vivo confirmed that the alterations of survivin-2B, IKK alpha, P73 and UVRAG were the same as that in vitro. Taken together, survivin-2B promoted autophagy and further regulated cell death by accumulating and stabilizing IKK alpha in the nucleus.


Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Quinase I-kappa B/metabolismo , Proteínas Inibidoras de Apoptose/metabolismo , Leucemia/enzimologia , Ácido Selenioso/farmacologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Animais , Núcleo Celular/enzimologia , Núcleo Celular/patologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação Leucêmica da Expressão Gênica , Células HCT116 , Humanos , Quinase I-kappa B/genética , Proteínas Inibidoras de Apoptose/genética , Células Jurkat , Leucemia/genética , Leucemia/patologia , Camundongos , Camundongos Nus , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Interferência de RNA , Transdução de Sinais/efeitos dos fármacos , Survivina , Transfecção , Proteína Tumoral p73 , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
6.
Cell Death Dis ; 4: e973, 2013 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-24357804

RESUMO

It has previously been shown that selenite can act as an antitumor agent and inhibit cancer cell growth, although the mechanism responsible for this effect is not well understood. In this study, we have shown that selenite can induce cell cycle arrest and apoptosis in NB4 cells. Selenite treatment of these cells also inhibited the JNK/ATF2 axis. Further experiments demonstrated that selenite-induced production of reactive oxygen species (ROS) worked as an upstream of the JNK/ATF2 axis, cell cycle arrest and apoptosis. Inactivation of ATF2 resulted in decreased affinity of this transcription factor for the promoters of cyclin A, cyclin D3 and CDK4, which led to the arrest of the NB4 cells in the G0/G1 phase. Finally, in vivo experiments confirmed the antitumor activity of selenite and the mechanisms that were described in vitro. Taken together, our results indicate that selenite-induced ROS arrest NB4 cells at G0/G1 phase through inhibiting the JNK/ATF2 axis in vitro and in vivo.


Assuntos
Fator 2 Ativador da Transcrição/metabolismo , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Ácido Selenioso/farmacologia , Fator 2 Ativador da Transcrição/genética , Animais , Linhagem Celular , Feminino , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Nus
7.
Talanta ; 55(4): 693-8, 2001 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-18968416

RESUMO

In this paper, the voltammetric method was used for the first time to study the effect of Cisplatin-liposome on Hela cells. The results showed the voltammetric behavior of Hela cells was irreversible and the peak current had linear relationship with the cell number. With both Cisplatin-liposome concentration and treating time increasing, the peak current decreased. The peak current decreasing was in accordance with the nuclear damage and loss of mitochondrial membrane potential revealed by two-photon laser scanning microscopy and confocal laser scanning microscopy. This voltammetric method may provide a simple way to study the electron-transfer mechanism in drug-treating cells.

8.
Anal Cell Pathol ; 18(2): 87-93, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10468405

RESUMO

Fourier transform infrared spectroscopic study of human breast normal and carcinomal tissues has been carried out. Some distinctive spectral differences which are mainly due to nucleic acids and proteins are observed between normal and carcinomal tissues. This method of analysis results in nearly 100% diagnostic accuracy of carcinomal tissues from normal tissues. The spectral patterns of well-differentiated carcinomal tissues exhibit marked heterogeneity, however that of poorly differentiated carcinomas demonstrate significant similarity. Apocrine, tubular, intraductal and mucinous carcinomas and invasive infiltrating ductal carcinomal tissues can be discriminated based on their characteristic spectra. The spectral differences confirm the possibility of using FTIR as an accurate and rapid technique to distinguish between normal and malignant breast tissues and classify breast carcinomas in different subtypes.


Assuntos
Neoplasias da Mama/patologia , Espectroscopia de Infravermelho com Transformada de Fourier , Adenocarcinoma/patologia , Adenocarcinoma Mucinoso/patologia , Glândulas Apócrinas/patologia , Carcinoma/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Carcinoma Medular/patologia , Feminino , Humanos
9.
Bioelectrochem Bioenerg ; 48(1): 171-5, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10228584

RESUMO

The electrochemical voltammetric behavior of bone marrow of leukaemia has been investigated by a self-devised cytosensing system. The two anodic peaks of erythrocytes (red blood cells, RBC) in bone marrow of leukaemia appeared at 0.73 +/- 0.03 and 0.83 +/- 0.02V vs. SCE, respectively, on the first scan. The anodic peak of leukocytes (white blood cells, WBC) appeared at 0.32 +/- 0.03V vs. SCE. The anodic peak of RBC at 0.83V disappeared when the patients were cured. The experimental results show that the voltammetric behavior of erythrocytes is in constant contact with the initial stage of leukaemia. The cyclic voltammetric behavior of 40 cases of leukaemia including acute myeloid leukaemia (AML) and chronic myeloid leukaemia (CML) and 10 cases of healthy volunteer peripheral blood was studied. The cyclic voltammetric behavior of erythrocytes may provide a simple and specific marker for diagnosis of leukaemia.


Assuntos
Medula Óssea/fisiopatologia , Leucemia/patologia , Medula Óssea/química , Soluções Tampão , Eletroquímica , Eletrofisiologia , Eritrócitos/fisiologia , Humanos , Leucemia/sangue , Leucemia/terapia , Leucemia Monocítica Aguda/sangue , Leucemia Monocítica Aguda/patologia , Leucemia Monocítica Aguda/terapia , Leucemia Mielogênica Crônica BCR-ABL Positiva/sangue , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Leucócitos/fisiologia
10.
Bioelectrochem Bioenerg ; 48(1): 217-22, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10228590

RESUMO

The voltammetric behavior of human mammalian cells was studied by choosing human leukemia cells (HL60) and human erythroleukemia cells (HEL). The voltammetric response of the cells was found having relation with cell metabolic viability in culture course. For example, the fluctuations of peak currents of HL60 were parallel with the nutrients replenished or not, which can reflect cell health state; the voltammetric response of HL60 regulated by the anti-metabolic drug 5F-Uriacil (5F-U) in culture course behaved in a much decreased manner, by which a voltammetric method for evaluating cytotoxicity is proposed. In this paper, the relation between HEL cell metabolism and the activation of receptor Mpl by its ligand TPO was also studied. Moreover, the mechanism of cell voltammetric behavior was discussed.


Assuntos
Células Tumorais Cultivadas/fisiologia , Antimetabólitos Antineoplásicos/farmacologia , Soluções Tampão , Divisão Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Eletrodos , Eletrofisiologia , Técnica Indireta de Fluorescência para Anticorpo , Fluoruracila/farmacologia , Células HL-60 , Humanos , Leucemia Eritroblástica Aguda , Trombopoetina/metabolismo , Células Tumorais Cultivadas/metabolismo
11.
Biotechnol Appl Biochem ; 26(3): 163-7, 1997 12.
Artigo em Inglês | MEDLINE | ID: mdl-9428155

RESUMO

The present paper describes a self-assembled monoclonal-antibody immunosensor for HT29 tumour cells. This immunosensor is composed of two parts. One is a three-electrode system and the other is a layer of anti-(human colonic tumour) monoclonal antibody DF-I, which self-assembled on to the gold electrode. Two kinds of cells, HT29 tumour cells and normal fibroblast cells, were compared using the antibody electrode. The result was the same as that obtained by using immune luminescence. The HT29 cells can be captured specifically by the assembled anti-HT29 monoclonal-antibody electrode and can be measured by an electrochemical method.


Assuntos
Anticorpos Monoclonais , Técnicas Biossensoriais , Eletrodos , Biotecnologia , Eletroquímica , Fluoresceína-5-Isotiocianato , Imunofluorescência , Células HT29 , Humanos , Fatores de Tempo
12.
J Immunol Methods ; 179(2): 233-41, 1995 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-7876570

RESUMO

Five beta-diketone derivatives were studied for multiple labelling of proteins. The labelled proteins were characterized by absorption and fluorescence measurements. It was found that proteins labelled with chlorosulfonyl-thenoyltrifluoroacetone (CTTA) were able to form highly fluorescent complexes with Eu3+ which exhibited prolonged fluorescence whereas the Eu3+ complex of hydrolyzed CTTA exhibited almost no fluorescence, and so unreacted ligand gave no background signal in immunoassays even if it was not removed from the labelled reagent. The effect of labelling on the biological activity of albumin and polyclonal antibody was studied and it was also shown that the new probe could be used in time-resolved fluorescence immunoassays.


Assuntos
Corantes Fluorescentes , Fluorimunoensaio/métodos , Animais , Anticorpos/química , Európio , Cetonas/química , Proteínas/química , Coelhos , Espectrometria de Fluorescência , Fatores de Tempo
13.
Arch Toxicol ; 69(9): 644-8, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8660143

RESUMO

Two artificial antigens, NalphaNepsilon-di(O,O-diisopropyl) phosphoryl L-lysine (DIP)- bovine serum albumin (BSA) conjugate (DIP-BSA) and DIP-KLH (keyhole limpet hemocyanin), were synthesized. Antibodies against sarin (O-isopropyl methylphosphonofluoridate) were obtained after immunization of rabbits with DIP-KLH conjugate. A competitive inhibition enzyme immunoassay (CIEIA) was developed to detect the organophosphorus nerve agent sarin. The antibody solutions could be inhibited by sarin as low as 10(-6) mol/l, and the standard curve was linear over 3 orders of magnitude. The coefficients of intraassay and interassay variation of this method were 5.4-6.2% (n = 11) and 8.0-9.5% (n = 6) at a sarin concentration range of 10(-3)-10(-6) mol/l, respectively. The recovery of sarin in water samples at the concentration of 5 x 10(-5) mol/l was in the range of 96.8-102.5%. The specificity of the antiserum was assessed by comparing the inhibition induced by sarin with soman, Vx, isopropyl alcohol and isopropyl methyl phosphonic acid. The results showed that less than 5 mmol/l soman, 2 mmol/l Vx, 16 mmol/l isopropyl alcohol and 8 mmol/l isopropyl methyl phosphonic acid did not influence the determination of sarin in water samples.


Assuntos
Sarina/análise , Animais , Ligação Competitiva , Feminino , Soros Imunes/biossíntese , Técnicas Imunoenzimáticas , Masculino , Fosfitos/análise , Fosfitos/imunologia , Coelhos , Sarina/imunologia
14.
Arch Toxicol ; 69(8): 565-7, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8534201

RESUMO

Two monoclonal antibodies (Vx-BB8 and Vx-EA11) to the chemical warfare agent Vx were produced and characterized. A competitive inhibition enzyme immunoassay was developed to detect Vx concentrations as low as 3.7 x 10(-7) - 3.7 x 10(-6) mol/l in biological samples. Vx-BB8 400 micrograms given intravenously immediately before 1 x LD95 Vx or 400 micrograms Vx-BB8 intraperitoneally 1.5 h-3 days before 1 x LD95 Vx could protect all the tested mice from death.


Assuntos
Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/uso terapêutico , Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/imunologia , Compostos Organotiofosforados/imunologia , Animais , Anticorpos Monoclonais/química , Inibidores da Colinesterase/toxicidade , Feminino , Imunização Passiva , Técnicas Imunoenzimáticas , Injeções Intraperitoneais , Injeções Intravenosas , Camundongos , Camundongos Endogâmicos BALB C , Compostos Organotiofosforados/toxicidade
15.
J Environ Pathol Toxicol Oncol ; 13(4): 231-4, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7658331

RESUMO

By using type I and type III collagen cDNA probe and cDNA-mRNA in situ hybridization, we observed the changes of rat lung alpha 1(I) and alpha 1(III) collagen gene expression in radiation interstitial pneumonitis. The results showed that the expressed cell of type I and type III collagen were scattered within the fibroblasts in the thickened interalveolar walls. The type I and type III collagen mRNA content in irradiated animals were higher than those in the controls at 0.5, 1, 2, 3, 6, and 12 months.


Assuntos
Colágeno/genética , Pneumonite por Radiação/genética , Animais , Colágeno/biossíntese , Expressão Gênica , Hibridização In Situ , Masculino , RNA Mensageiro/genética , Ratos , Ratos Wistar
16.
Analyst ; 117(8): 1377-8, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-1443636

RESUMO

A spectrofluorimetric method, involving alkaline degradation and formation of a magnesium complex, is described for the determination of tetracycline (TC) and anhydrotetracycline (ATC) in their mixed solution. Tetracycline is degraded and determined in alkaline solution. This treatment of ATC produces almost no fluorescence, but a fluorescent magnesium complex forms at pH 7.5. Several synthetic samples of TC and ATC, with TC:ATC ratios ranging from 50:1 to 1:50, were analysed. The recoveries of TC and ATC are about 71-76 and 61-63% in serum, respectively, and are all about 100% in urine.


Assuntos
Tetraciclina/sangue , Tetraciclina/urina , Tetraciclinas/sangue , Tetraciclinas/urina , Humanos , Espectrometria de Fluorescência/métodos
17.
Talanta ; 38(10): 1159-62, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18965277

RESUMO

The quantitative spectrophotometric determination of V(V) by its catalytic effect on the oxidation of chromotropic acid [the disodium salt of 4,5-dihydroxynaphthalene-2,7-disulphonic acid (CS)] by potassium bromate has been adapted to a flow system employing a rapid sample and reagent introduction manifold, in which valves and carrier streams are omitted without decreasing the precision or increasing the sample consumption relative to flow-injection analysis (FIA). Measurements are made at 420 nm. Coexisting Fe(III) can be determined simultaneously at the same wavelength by its more rapid colour chelate formation with CS. An accurate determination of V(V) and Fe(III) in the mixture was developed with a sample throughput of about 60 hr.

18.
Talanta ; 37(12): 1133-6, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18965084

RESUMO

The relative ability of peroxidase-like metallotetrakis(N-methylpyridiniumyl)porphyrins [Me-TMPyP, Me = Mn(III), Fe(III), Co(III), Ni(II), Cu(II), and Zn(II)] to catalyse the hydrogen peroxide oxidation of homovanillic acid to a fluorescent dimer has been studied. The complexes of Mn, Fe and Co are effective catalysts in the reaction, but the complexes of Ni, Cu and Zn are not. The catalytic behaviour of Mn-TMPyP, Fe-TMPyP and Co-TMPyP has been compared with that of HRP in both enzymatic and kinetic analysis. The sequence of peroxidase-like catalytic activity is Mn-TMPyP > Co-TMPyP > Fe-TMPyP. The catalytic activity of Mn-TMPyP is 84% of that of HRP. These Me-TMPyP (Me = Mn, Fe, and Co) compounds are good substitutes for HRP in enzymatic analysis. Traces of hydrogen peroxide and glucose can be determined with the Me-TMPyP systems.

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