992 resultados para CYTOTOXIC ACTIVITY
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The number and activity of natural killer (NK) cells were studied in 34 untreated patients with paracoccidioidomycosis, 20 with the chronic form of the disease and 14 with the acute form. NK cells were detected with monoclonal antibody Leu-11c and the cytotoxic activity was measured using a single cell assay against K562 target cells. Both groups of patients had an increased number of circulating NK cells, their cytotoxic activity being significantly lower than in the healthy controls. These findings may be of importance in the immunological disturbances associated with paracoccidioidomycosis since NK cells exert important immune effector functions and may play a role in resistance against Paracoccidioides brasiliensis.
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CR-LAAO is an l-amino acid oxidase from Calloselasma rhodostoma snake venom that has been broadly studied regarding its structural and biochemical characteristics, however, few studies have investigated its pharmacological effects. The present study aimed at the evaluation of the biotechnological potential of CR-LAAO by determining its bactericidal, antifungal, leishmanicidal and trypanocidal activity, as well as its cytotoxicity on human tumor and non-tumor cell lines. After 24h of preincubation, CR-LAAO showed bactericidal effects against both Staphylococcus aureus (MIC 0.78μg/mL) and Escherichia coli (MIC 31.25μg/mL) strains, inducing dismantle of bacterial cell walls. After 6h of preincubation with Candida albicans, CR-LAAO was able to inhibit 80% of the yeast growth, and it also showed cytotoxic activity on Leishmania species and Trypanosoma cruzi. Additionally, CR-LAAO showed high cytotoxicity on HepG2 and HL-60 tumor cells (IC50 10.78 and 1.7μg/mL), with lower effects on human mononuclear cells (PBMC). The cytotoxic effects of CR-LAAO were significantly inhibited in the presence of catalase, which suggests the involvement of hydrogen peroxide in its mechanisms of toxicity. Therefore, CR-LAAO showed promising pharmacological effects, and these results provide important information for the development of therapeutic strategies with directed action, such as more effective antimicrobial agents.
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Species of the genus Qualea are used by the Brazilian public as a natural anti-inflammatory. Based on this evidence, we evaluated the effects of terpene fractions (βF and TF) obtained from Qualea multiflora on nitric oxide production (Griess assay), cytokines (IL-1, IL-10, IL-12, and TNF-a) and the transcription factor NF-κB by peritoneal macrophages. Since there is a relationship between inflammation and cancer, the cytotoxicity of βF and TF against mammary tumoural cell lineage, and macrophages was evaluated. Inhibition levels close to 90% of the production of NO, IL-1, IL-12 and TNF-a; about 32% of NF-κB; and a large stimulation of IL-10 production (close to the positive control) by peritoneal macrophages were observed in response to βF and TF which are correlated with anti-inflammatory activity. Additionally, the samples showed exceptional cytotoxic activity against tumoural cells but not against macrophages. Since anti-inflammatory activity is important in tumour inhibition, further examination of potential anti-cancerous activity of Qualea multiflora is warranted.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Biopatologia Bucal - ICT
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The Casearia genus (Salicaceae) is well known because of the medicinal use of its species. Among them, a noteworthy one is the C. sylvestris specie because it already has studies concerning its antiproliferative and/or cytotoxic activity in tumor cells. Furthermore, this specie is popularly used against snake bites, in gastric ulcers treatment and as anti-inflammatory. As well as this, there are other species from this same genus which have been poorly studied, such as the following species: C. decandra, C. grandiflora, C. javitensis, C. arborea, C. lasiophylla and C. ulmifolia. However, several biological activities have been reported for them. In this context, the aim of this project, besides of contributing to the Casearia genus studies, is to study those six species through the analysis and documentation of their leaves' chemical composition (aqueous, ethanolic and hexanic extracts), using analytical separation techniques coupled with spectroscopic techniques, such as UHPLC-DAD, GC-MS and NMR 1H, which will assist the identification of new secondary metabolites in this genus. Moreover, another goal of this present work is aiming the bioprospection of substances with medicinal and economical potential and finally promote the systematic study of some biological activities, such as antimicrobial and cytotoxicity bioassays. A wide variety of metabolites was identified in those three types of extracts, being most of them detected for the first time in Casearia genus, highlighting C. lasiophylla and C. decandra for featuring antimicrobial activity against Staphylococcus aureus.
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The Casearia genus (Salicaceae) is well known because of the medicinal use of its species. Among them, a noteworthy one is the C. sylvestris specie because it already has studies concerning its antiproliferative and/or cytotoxic activity in tumor cells. Furthermore, this specie is popularly used against snake bites, in gastric ulcers treatment and as anti-inflammatory. As well as this, there are other species from this same genus which have been poorly studied, such as the following species: C. decandra, C. grandiflora, C. javitensis, C. arborea, C. lasiophylla and C. ulmifolia. However, several biological activities have been reported for them. In this context, the aim of this project, besides of contributing to the Casearia genus studies, is to study those six species through the analysis and documentation of their leaves' chemical composition (aqueous, ethanolic and hexanic extracts), using analytical separation techniques coupled with spectroscopic techniques, such as UHPLC-DAD, GC-MS and NMR 1H, which will assist the identification of new secondary metabolites in this genus. Moreover, another goal of this present work is aiming the bioprospection of substances with medicinal and economical potential and finally promote the systematic study of some biological activities, such as antimicrobial and cytotoxicity bioassays. A wide variety of metabolites was identified in those three types of extracts, being most of them detected for the first time in Casearia genus, highlighting C. lasiophylla and C. decandra for featuring antimicrobial activity against Staphylococcus aureus.
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The Asteraceae, one of the largest families among angiosperms, is chemically characterised by the production of sesquiterpene lactones (SLs). A total of 1,111 SLs, which were extracted from 658 species, 161 genera, 63 subtribes and 15 tribes of Asteraceae, were represented and registered in two dimensions in the SISTEMATX, an in-house software system, and were associated with their botanical sources. The respective 11 block of descriptors: Constitutional, Functional groups, BCUT, Atom-centred, 2D autocorrelations, Topological, Geometrical, RDF, 3D-MoRSE, GETAWAY and WHIM were used as input data to separate the botanical occurrences through self-organising maps. Maps that were generated with each descriptor divided the Asteraceae tribes, with total index values between 66.7% and 83.6%. The analysis of the results shows evident similarities among the Heliantheae, Helenieae and Eupatorieae tribes as well as between the Anthemideae and Inuleae tribes. Those observations are in agreement with systematic classifications that were proposed by Bremer, which use mainly morphological and molecular data, therefore chemical markers partially corroborate with these classifications. The results demonstrate that the atom-centred and RDF descriptors can be used as a tool for taxonomic classification in low hierarchical levels, such as tribes. Descriptors obtained through fragments or by the two-dimensional representation of the SL structures were sufficient to obtain significant results, and better results were not achieved by using descriptors derived from three-dimensional representations of SLs. Such models based on physico-chemical properties can project new design SLs, similar structures from literature or even unreported structures in two-dimensional chemical space. Therefore, the generated SOMs can predict the most probable tribe where a biologically active molecule can be found according Bremer classification.
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Purpose: Our objective was to relate immunological data for healthy but sedentary elderly women to aerobic power, strength, and mood state. Methods: We measured peak aerobic power and one-repetition maximum strength along with mood (depression and fatigue), quality of life and carbohydrate intake on 42 women aged 60-77 years. Standard immunological techniques determined natural killer cell count and cytotoxic activity (NKCA), proliferative responses to phytohemaglutinin and OKT3, various lymphocyte subpopulations (CD3(+), CD3(-)CD19(+), CD56(+), CD4(+), CD8(+), CD56(dim) and CD56(bright)), and markers of activation, maturation, down-regulation and susceptibility to apoptosis (CD25(+), CD28(+), CD45RA(+), CD45RO(+), CD69(+), CD95(+), HLA-DR+). Results: Correlations of immune parameters with aerobic power and strength were very similar for absolute and relative immunological data. In the group as a whole, the only correlation with aerobic power was -0.35 (relative CD4(+)CD69(+) count), but in subjects with values <22.6 mL kg(-1) min(-1) correlations ranged from -0.57 (relative CD4(+)CD45RO(+)) to 0.92 (absolute CD56(dim)HLA-DR+). In terms of muscle strength, univariate correlation coefficients ranged from -0.34 (relative and absolute CD3(+)CD4(+)CD8(+)) to +0.48 (absolute CD3(+)HLA-DR+.) and +0.50 (absolute CD8(+)CD45RA(+)CD45RO(+)). Neither NKCA nor lymphocyte proliferation were correlated with aerobic power or muscle strength. Although mood state and quality of life can sometimes be influenced by an individual's fitness level, our multivariate analyses suggested that depression, fatigue and quality of life were more important determinants of immune profile than our fitness measures. Conclusions: Psychological changes associated with aging may have a substantial adverse effect upon the immune system, and immunological function may be enhanced more by addressing these issues than by focusing upon aerobic or resistance training. (C) 2012 Elsevier Inc. All rights reserved.
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The aim of this study was the isolation of the LAAO from Lachesis muta venom (LmLAAO) and its biochemical, functional and structural characterization. Two different purification protocols were developed and both provided highly homogeneous and active LmLAAO. It is a homodimeric enzyme with molar mass around 120 kDa under non-reducing conditions, 60 kDa under reducing conditions in SDS-PAGE and 60852 Da by mass spectrometry. Forty amino acid residues were directly sequenced from LmLAAO and its complete cDNA was identified and characterized from an Expressed Sequence Tags data bank obtained from a venom gland. A model based on sequence homology was manually built in order to predict its three-dimensional structure. LmLAAO showed a catalytic preference for hydrophobic amino acids (K-m of 0.97 mmol/L with Leu). A mild myonecrosis was observed histologically in mice after injection of 100 mu g of LmLAAO and confirmed by a 15-fold increase in CK activity. LmLAAO induced cytotoxicity on AGS cell line (gastric adenocarcinoma, IC50: 22.7 mu g/mL) and on MCF-7 cell line (breast adenocarcinoma, IC50:1.41 mu g/mL). It presents antiparasitic activity on Leishmania brasiliensis (IC50: 2.22 mu g/nnL), but Trypanosoma cruzi was resistant to LmLAAO. In conclusion, LmLAAO showed low systemic toxicity but important in vitro pharmacological actions. (C) 2012 Elsevier Ltd. All rights reserved.
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The biotransformation of the sesquiterpene lactone tagitinin C by the fungus Aspergillus terreus MT 5.3 yielded a rare derivative that was elucidated by spectrometric methods. The fungus led to the formation of a different product through an unusual epoxidation reaction between C4 and C5, formation of a C3,C10 ether bridge, and a methoxylation of the C1 of tagitinin C. The chemical structure of the product, namely 1 beta-methoxy-3 alpha-hydroxy-3,10 beta-4,5 alpha-diepoxy-8 beta-isobutyroyloxygermacr-11(13)-en-6 alpha,12-olide, is the same as that of a derivative that was recently isolated from the flowers of a Brazilian population of Mexican sunflower (Tithonia diversifolia), which is the source of the substrate tagitinin C. The in vitro cytotoxic activity of the substrate and the biotransformed product were evaluated in HL-60 cells using an MTT assay, and both compounds were found to be cytotoxic. We show that soil fungi may be useful in the biotransformation of sesquiterpene lactones, thereby leading to unusual changes in their chemical structures that may preserve or alter their biological activities, and may also mimic plant biosynthetic pathways for production of secondary metabolites.
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Introduction: The cytolysis mediated by granules is one of the most important effector functions of cytotoxic T lymphocytes and natural killer cells. Recently, three single nucleotide polymorphisms (SNPs) were identified at exons 2, 3, and 5 of the granzyme B gene, resulting in a haplotype in which three amino acids of mature protein Q48P88Y245 are changed to R48A88H245, which leads to loss of cytotoxic activity of the protein. In this study, we evaluated the frequency of these polymorphisms in Brazilian populations. Methods: We evaluated the frequency of these polymorphisms in Brazilian ethnic groups (white, Afro-Brazilian, and Asian) by sequencing these regions. Results: The allelic and genotypic frequencies of SNP 2364A/G at exon 2 in Afro-Brazilian individuals (42.3% and 17.3%) were significantly higher when compared with those in whites and Asians (p < 0.0001 and p = 0.0007, respectively). The polymorphisms 2933C/G and 4243C/T also were more frequent in Afro-Brazilians but without any significant difference regarding the other groups. The Afro-Brazilian group presented greater diversity of haplotypes, and the RAH haplotype seemed to be more frequent in this group (25%), followed by the whites (20.7%) and by the Asians (11.9%), similar to the frequency presented in the literature. Conclusions: There is a higher frequency of polymorphisms in Afro-Brazilians, and the RAH haplotype was more frequent in these individuals. We believe that further studies should aim to investigate the correlation of this haplotype with diseases related to immunity mediated by cytotoxic lymphocytes, and if this correlation is confirmed, novel treatment strategies might be elaborated.