Base de dados : LILACS
Pesquisa : D03.633.300.953 [Categoria DeCS]
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  1 / 9 LILACS  
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Id: lil-755830
Autor: Alnimr, Amani M.
Título: Dormancy models for Mycobacterium tuberculosis: A minireview
Fonte: Braz. j. microbiol;46(3):641-647, July-Sept. 2015. tab, ilus.
Idioma: en.
Resumo:

Dormancy models for Mycobacterium tuberculosis play important roles in understanding various aspects of tuberculosis pathogenesis and in the testing of novel therapeutic regimens. By simulating the latent tuberculosis infection, in which the bacteria exist in a non-replicative state, the models demonstrate reduced susceptibility to antimycobacterial agents. This minireview outlines the models available for simulating latent tuberculosis both in vitro and in several animal species. Additionally, this minireview discusses the advantages and disadvantages of these models for investigating the bacterial subpopulations and susceptibilities to sterilization by various antituberculosis drugs.

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  2 / 9 LILACS  
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Id: lil-684524
Autor: Brazilian Journal of Medical and Biological Research; Sheng, W.J.; Jiang, H.; Wu, D.L.; Zheng, J.H..
Título: Early responses of the STAT3 pathway to platinum drugs are associated with cisplatin resistance in epithelial ovarian cancer
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;46(8):650-658, ago. 2013. graf.
Idioma: en.
Projeto: the National Natural Science Foundation of China.
Resumo: Cisplatin resistance remains one of the major obstacles when treating epithelial ovarian cancer. Because oxaliplatin and nedaplatin are effective against cisplatin-resistant ovarian cancer in clinical trials and signal transducer and activator of transcription 3 (STAT3) is associated with cisplatin resistance, we investigated whether overcoming cisplatin resistance by oxaliplatin and nedaplatin was associated with the STAT3 pathway in ovarian cancer. Alamar blue, clonogenic, and wound healing assays, and Western blot analysis were used to compare the effects of platinum drugs in SKOV-3 cells. At an equitoxic dose, oxaliplatin and nedaplatin exhibited similar inhibitory effects on colony-forming ability and greater inhibition on cell motility than cisplatin in ovarian cancer. Early in the time course of drug administration, cisplatin increased the expression of pSTAT3 (Tyr705), STAT3α, VEGF, survivin, and Bcl-XL, while oxaliplatin and nedaplatin exhibited the opposite effects, and upregulated pSTAT3 (Ser727) and STAT3β. The STAT3 pathway responded early to platinum drugs associated with cisplatin resistance in epithelial ovarian cancer and provided a rationale for new therapeutic strategies to reverse cisplatin resistance.
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  3 / 9 LILACS  
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Id: lil-643749
Autor: Escribano, Alexandra Ibáñez; Marcel, Alfredo Meneses; Tugores, Yanetsy Machado; Ruiz, Juan José Nogal; Redó, Vicente J Arán; García-Trevijano, José Antonio Escario; Barrio, Alicia Gómez.
Título: Validation of a modified fluorimetric assay for the screening of trichomonacidal drugs
Fonte: Mem. Inst. Oswaldo Cruz;107(5):637-643, Aug. 2012. ilus, tab.
Idioma: en.
Projeto: AECID; . MICINN; . CEI-Campus Moncloa.
Resumo: A fluorimetric microassay that uses a redox dye to determine the viability of the flagellate Trichomonas vaginalis has been optimised to provide a more sensitive method to evaluate potential trichomonacidal compounds. Resazurin has been used in recent years to test drugs against different parasites, including trichomonadid protozoa; however, the reproducibility of these resazurin-based methods in our laboratory has been limited because the flagellate culture medium spontaneously reduces the resazurin. The objective of this work was to refine the fluorimetric microassay method previously developed by other research groups to reduce the fluorescence background generated by the media and increase the sensitivity of the screening assay. The experimental conditions, time of incubation, resazurin concentration and media used in the microtitre plates were adjusted. Different drug sensitivity studies against T. vaginalis were developed using the 5-nitroimidazole reference drugs, new 5-nitroindazolinones and 5-nitroindazole synthetic derivatives. Haemocytometer count results were compared with the resazurin assay using a 10% solution of 3 mM resazurin dissolved in phosphate buffered saline with glucose (1 mg/mL). The fluorimetric assay and the haemocytometer counts resulted in similar percentages of trichomonacidal activity in all the experiments, demonstrating that the fluorimetric microtitre assay has the necessary accuracy for high-throughput screening of new drugs against T. vaginalis.
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  4 / 9 LILACS  
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Id: lil-643741
Autor: Coban, Ahmet Yilmaz; Uzun, Meltem; Akgunes, Alper; Durupinar, Belma.
Título: Comparative evaluation of the microplate nitrate reductase assay and the rezasurin microtitre assay for the rapid detection of multidrug resistant Mycobacterium tuberculosis clinical isolates
Fonte: Mem. Inst. Oswaldo Cruz;107(5):578-581, Aug. 2012. ilus, tab.
Idioma: en.
Resumo: The microplate nitrate reductase assay (MNRA) and the rezasurin microtitre assay (REMA) were used for the susceptibility testing of 73 clinical isolates and the results were compared with those that were obtained using the Bactec 460 TB and Bactec MGIT 960 systems. The REMA and the MNRA were performed in 96-well plates. For the REMA, the concentrations of isoniazid (INH) and rifampicin (RIF) ranged from 1.0-0.01 µg/mL and 2.0-0.03 µg/mL, respectively. For the MNRA, the INH concentration was between 1.0-0.03 µg/mL and the RIF concentration was between 2.0-0.06 µg/mL. For the MNRA, the sensitivity, specificity, positive predictive value, negative predictive value and INH/RIF agreement were 100/95.6, 97.6/100, 96.8/100, 100/98 and 98.6/98.6, respectively, and for the REMA, they were 100/91.3, 90.4/100, 88.5/100, 100/96.1 and 94.5/97.2, respectively. Our data suggest that these two rapid, low-cost methods may be inexpensive, alternative assays for the rapid detection of multidrug resistant tuberculosis in low-income countries.
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  5 / 9 LILACS  
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Id: lil-530261
Autor: Borra, Ricardo Carneiro; Lotufo, Mônica Andrade; Gagioti, Sonia Maria; Barros, Fabiana de Mesquita; Andrade, Priscila Maria.
Título: A simple method to measure cell viability in proliferation and cytotoxicity assays
Fonte: Braz. oral res;23(3):255-262, 2009. graf, ilus.
Idioma: en.
Resumo: Resazurin dye has been broadly used as indicator of cell viability in several types of assays for evaluation of the biocompatibility of medical and dental materials. Mitochondrial enzymes, as carriers of diaphorase activities, are probably responsible for the transference of electrons from NADPH + H+ to resazurin, which is reduced to resorufin. The level of reduction can be quantified by spectrophotometers since resazurin exhibits an absorption peak at 600 çm and resorufin at 570 çm wavelengths. However, the requirement of a spectrophotometer and specific filters for the quantification could be a barrier to many laboratories. Digital cameras containing red, green and blue filters, which allow the capture of red (600 to 700 çm) and green (500 to 600 çm) light wavelengths in ranges bordering on resazurin and resorufin absorption bands, could be used as an alternative method for the assessment of resazurin and resorufin concentrations. Thus, our aim was to develop a simple, cheap and precise method based on a digital CCD camera to measure the reduction of resazurin. We compared the capability of the CCD-based method to distinguish different concentrations of L929 and normal Human buccal fibroblast cell lines with that of a conventional microplate reader. The correlation was analyzed through the Pearson coefficient. The results showed a strong association between the measurements of the method developed here and those made with the microplate reader (r² = 0.996; p < 0.01) and with the cellular concentrations (r² = 0.965; p < 0.01). We concluded that the developed Colorimetric Quantification System based on CCD Images allowed rapid assessment of the cultured cell concentrations with simple equipment at a reduced cost.
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  6 / 9 LILACS  
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Rodrigues, V. L. C. C
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Id: lil-418150
Autor: Moraes, A. S; Pimentel, E. R; Rodrigues, V. L. C. C; Mello, M. L. S.
Título: Eye pigments of the blood-sucking insect, Triatoma infestans klug (Hemiptera, Reduviidae)
Fonte: Braz. j. biol;65(3):477-481, Aug. 2005. graf.
Idioma: en.
Resumo: A pigmentação de olhos pretos (forma selvagem) e vermelhos (forma mutante) de Triatoma infestans foi estudada por espectrofotometria e comparada à de olhos vermelhos (selvagem) e brancos (mutante) de Drosophila melanogaster. Os perfis do espectro de absorção dos pigmentos de olho preto e vermelho de T. infestans foram semelhantes entre si e ao dos olhos de tipo selvagem de D. melanogaster. A similaridade com a forma selvagem de D. melanogaster indicou que ambos os tipos de olho de T. infestans continham omocromos do tipo xantomatina, o que foi confirmado por cromatografia ascendente em papel. Não foram detectadas pteridinas, melaninas e ominas como pigmentos de olho em T. infestans. A diferença na cor de olho em T. infestans foi considerada uma função da concentração de xantomatina, sendo menor o conteúdo de omocromo nos olhos vermelhos, embora isso provavelmente não afete a acuidade visual do inseto. Esses resultados estão de acordo com dados de outros autores quanto a semelhanças envolvendo outras características entre espécimes de olho preto e vermelho de T. infestans.
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  7 / 9 LILACS  
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Young, Maria Claudia Marx
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Id: lil-344253
Autor: Pinheiro, Lucimar; Nakamura, Celso Vataru; Dias Filho, Benedito Prado; Ferreira, Antonio Gilberto; Young, Maria Claudia Marx; Cortez, Aparicio Garcia.
Título: Antibacterial xanthones from Kielmeyera variabilis mart. (Clusiaceae)
Fonte: Mem. Inst. Oswaldo Cruz;98(4):549-552, June 2003. ilus, tab, graf.
Idioma: en.
Resumo: The bioassay-guided fractionation of stems from Kielmeyera variabilis, traditionally used in Brazilian folk medicine, yielded assiguxanthone-B (1), kielcorin (4), 2,5-dihydroxybenzoic acid (3), and a mixture of xanthones containing assiguxanthone-B (1) and 1,3,5,6-tetrahydroxy-2-prenylxanthone (2) (1:1 w/w). The xanthone mixture inhibited Staphylococcus aureus and Bacillus subtilis at a concentration of 6.25 µg/ml. When tested alone, the minimal inhibitory concentration of assiguxanthone-B was 25 µg/ml against B. subtilis. Kielcorin and 2,5-dihydroxybenzoic acid were inactive against both strains. None of the fractions was active against Escherichia coli or Pseudomonas aeruginosa. Viable cells of S. aureus were reduced by a 1-3 log CFU/ml within 12 h after exposure of one to eight times the MIC of the xanthone mixture. It is not known whether the tetrahydroxy-2-prenylxanthone or other components of the xanthone mixture are responsible for the main antibacterial activity or whether additive or synergistic action is involved
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  8 / 9 LILACS  
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Barreto, R. C
Id: lil-23460
Autor: Barreto, R. C; Patricio, S. F.
Título: Ensaio clinico do uso de tranquilizantes em odontopediatria. / Clinical trial of the use of tranquilizers in odontopediatrics
Fonte: CCS;6(3):51-5, jul.-set. 1984.
Idioma: pt.
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  9 / 9 LILACS  
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Id: lil-15212
Autor: Dolmann, A; Lavallen, E; Forti, I. N.
Título: Evaluacion de la actividad del RU 31156 en pacientes con asma extrinseca. / Evaluation of the activity of RU 31156 in patients with extrinsic asthma
Fonte: Prensa méd. argent;70(6):249-55, 1983.
Idioma: es.
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