610 resultados para Roberto Echavarren
Resumo:
The purified beta-glucosidase of Aureobasidium pullulans ER-16 is one of more thermostable enzyme reported to date. Considering the unfeasibility of using purified enzyme for industrial application, it was interesting to analyze this property for the crude enzyme. Thermophilic fungus Thermoascus aurantiacus CBMAI-756 and mesophilic A. pullulans ER-16 were cultivated in different hemicellulosic materials on solid-state cultivation for beta-glucosidase production. Wheat bran was most appropriate for beta-glucosidase production by both microorganisms. T. aurantiacus exhibited maximum enzyme production (7.0 U/ml or 70 U/g) at 48-72 h and A. pullulans a maximum (1.3 U/ml or 13 U/g) at 120 h. Maximum activities were at 75 degrees C with optimum pH at 4.5 and 4.0, for T aurantiacus and A. pullulans, respectively. A. pullulans`s beta-glucosidase was more pH stable (4.5-10.0 against 4.5-8.0) and more thermostable (90% after 1 h at 75 degrees C against 85% after 1 h at 70 degrees C) than the enzyme from the thermophilic T. aurantiacus. The t((1/2)) at 80 degrees C were 50 and 12.5 min for A. pullulans and T. aurantiascus, respectively. These data confirm the high thermostability of crude beta-glucosidase from A. pullulans. Both beta-glucosidases were strongly inhibited by glucose, but ethanol significantly increased the activity of the enzyme from T. aurantiacus. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
The in vitro antileishmanial activity of Brazilian green propolis hydroalcoholic extract (BPE) were carried out on Leishmania (Viannia) braziliensis against both promastigote (doses ranging from 1 to 750 mu g mL(-1)) and amastigote (10, 100, and 250 mu g mL(-1)) assays in comparison with the positive (amphotericin B) and negative (dimethyl sulfoxide at 1% in physiologic solution) control groups. BPE displayed in vitro antileishmanial activities against promastigote forms of the parasite (p<0.05). However, it was inactive against its amastigote ones. In the in vitro cytotoxicity assay against Vero cells, BPE showed no cytotoxicity in the maximum doses tested. The high-performance liquid chromatography analysis allowed the identification of caffeic acid, p-coumaric acid, aromadendrine-4`-methyl-ether, 3-prenyl-p-coumaric acid (drupanin), and 3,5-diprenil-p-cumarico acid (artepillin C) as major compounds of BPE. In the in vivo assay, using a Balb/C lineage of Mus musculus male mice, groups of ten animals each were treated (1.5 mg kg day(-1)) with BPE orally (group 1), BPE topically (group 2), BPE orally and topically (group 3), and glucantime (group 4), using NaCl 0.9% (group 5) as the negative control group. Groups 1, 2, and 3 displayed a decrease on lesion development, after 90 days of treatment, by 78.6%, 84.3%, and 90.0%, respectively, while the glucantime-treated group showed 57.7% of decrease, all in comparison with the negative control group. It is the first time that the in vivo antileishmanial activity has been reported for Brazilian green propolis.
Resumo:
(+/-)-Licarin A (1), a neolignan obtained by the oxidative coupling reaction of isoeugenol, had in this study its enantiomers resolved. A novel, quick and efficient enantiomeric resolution of 1 was directly performed by chiral high-performance liquid chromatography (HPLC-PDA) protocol (CHIRALPACK (R) AD column; 9:1 (v/v) n-hexane:2-propanol; 1.0 mL/min). This method provided a chromatogram profile with a well-resolved peak separation. After isolation of each enantiomer with ee >99.9%, they were analysed in a polarimeter. Compound 2, which showed a retention time (t(r)) of 12.13 min, was the (+)-enantiomer and compound 3 (t(r) =18.90 min) was the (-)-enantiomer. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
Solanum lycocarpum A. St. Hil. (Solanaceae) is a hairy shrub or small much-branched tree of the Brazilian Cerrado. S. lycocarpum fruits are commonly used in traditional medicine in powder form or as folk preparations for the treatment of diabetes and obesity, as well as for controlling cholesterol levels. The aim of the present study was to chemically characterize the hydroalcoholic extract (SL) of S. lycocarpum by determination of total flavonoids and total poyphenols and quantification of steroidal alkaloids, as well as to evaluate its mutagenic and/or antimutagenic potential on V79 cells and Swiss mice using chromosomal aberrations and bone marrow micronucleus assays, respectively. Three concentrations of SL (16, 32, and 24 mu g/mL) were used for the evaluation of its mutagenic potential in V79 cells and four doses (0.25, 0.50, 1.0, and 2.0 g/kg body weight) were used for Swiss mice. In the antimutagenicity assays, the different concentrations of SL were combined with the chemotherapeutic agent doxorubicin (DXR). HPLC analysis of SL gave contents of 6.57% +/- 0.41 of solasonine and 4.60% +/- 0.40 of solamargine. Total flavonoids and polyphenols contents in SL were 0.04 and 3.60%, respectively. The results showed that not only SL exerted no mutagenic effect, but it also significantly reduced the frequency of chromosomal aberrations induced by DXR in both V79 cells and micronuclei in Swiss mice at the doses tested.
Resumo:
No fully effective treatment has been developed since the discovery of Chagas` disease. Since drug-resistant Trypanosoma cruzi strains are occurring and the current therapy is effective in the acute phase but with various adverse side effects, more studies are needed to characterize the susceptibility of T. cruzi to new drugs. Pre-mRNA maturation in trypanosomatids occurs through a process called trans-splicing, which is unusual RNA processing reaction, and it implies the processing of polycistronic transcription units into individual mRNAs; a short transcript spliced leader (SL RNA) is trans-spliced to the acceptor pre-mRNA, giving origin to the mature mRNA. Cubebin derivatives seem to provide treatments with less collateral effects than benznidazole and showed similar or better trypanocidal activities than benznidazole. Therefore, the cubebin derivatives ((-)-6,6`-dinitrohinokinin (DNH) and (-)-hinokinin (HQ)) interference in the mRNA processing was evaluated using T. cruzi permeable cells (Y and BOL (Bolivia) strains) following by RNase protection reaction. These substances seem to intervene in any step of the RNA transcription, promoting alterations in the RNA synthesis, even though the RNA processing mechanism still occurs. Furthermore, HQ presented better activity against the parasites than DNH, meaning that BOL strain seems to be more resistant than Y.
Resumo:
Budlein A has been reported to exert some analgesic and anti-inflammatory properties. In this study, we have evaluated its effect on LPS-induced leukocyte recruitment in vivo and the mechanisms involved in its anti-inflammatory activity. In vivo, intravital videomicroscopy was used to determine the effects of budlein A on LPS-induced leukocyte-endothelial cell interactions in the murine cremasteric microcirculation. In vitro, the effects of budlein A on LPS-induced cytokine, chemokine and nitrites release, T-cell proliferative response as well as cell adhesion molecule expression (CAM) were evaluated. In vivo, intraperitoneal administration of budlein A (2.6 mM/kg) caused a significant reduction of LPS-induced leukocyte rolling flux, adhesion and emigration by 84, 92 and 96% respectively. In vitro, T-cell proliferative response was also affected by budlein A. When murine J774 macrophages were incubated with the sesquiterpene lactone, LPS-induced IL-1 beta, tumor necrosis factor-alpha (TNF-alpha) and keratinocyte-derived chemokine (KC) release were concentration-dependently inhibited. In human umbilical vein endothelial cells (HUVECs), budlein A also reduced the production of TNF-alpha, monocyte chemoattractant protein-1 (MCP-1), IL-8, nitrites and CAM expression elicited by LPS. Budlein A is a potent inhibitor of LPS-induced leukocyte accumulation in vivo. This effect appears to be mediated through inhibition of cytokine and chemokine release and down-regulation of CAM expression. Thus, it has potential therapeutic interest for the control of leukocyte recruitment that occurs in different inflammatory disorders. (C) 2009 Elsevier GrnbH. All rights reserved.
Resumo:
The aim of this work was to investigate the involvement of caspases in apoptosis induced by L-amino acid oxidase isolated from Bothrops atrox snake venom. The isolation of LAAO involved three chromatographic steps: molecular exclusion on a G-75 column; ion exchange column by HPLC and affinity chromatography on a Lentil Lectin column. SDS-PAGE was used to confirm the expected high purity level of BatroxLAA0. It is a glycoprotein with 12% sugar and an acidic character, as confirmed by its amino acid composition, rich in ""Asp and Glu"" residues. It displays high specificity toward hydrophobic L-amino acids. The N-terminal amino acid sequence and internal peptide sequences showed close structural homology to other snake venom LAAOs. This enzyme induces in vitro platelet aggregation, which may be due to H(2)O(2) production by LAAOs, since the addition of catalase completely inhibited the aggregation effect. It also showed cytotoxicity towards several cancer cell lines: HL60, Jurkat, B16F10 and PC12. The cytotoxicity activity was abolished by catalase. A fluorescence microscopy evaluation revealed a significant increase in the apoptotic index of these cells after BatroxLAAO treatment. This observation was confirmed by phosphatidyl serine exposure and activation of caspases. BatroxLAAO is a protein with various biological functions that can be involved in envenomation. Further investigations of its function will contribute to toxicology advances. Published by Elsevier Inc.
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PGE(2), an arachidonic acid metabolite produced by various type of cells regulates a broad range of physiological activities in the endocrine, cardiovascular, gastrointestinal, and immune systems, and is involved in maintaining the local homeostasis. In the immune system, PGE(2) is mainly produced by APCs and it can suppress the Th1-mediated immune responses. The aim of this study was to develop PGE(2)-loaded biodegradable MS that prolong and sustain the in vivo release of this mediator. An o/w emulsion solvent extraction-evaporation method was chosen to prepare the MS. We determined their diameters, evaluated the in vitro release of PGE(2), using enzyme immunoassay and MS uptake by peritoneal macrophages. To assess the preservation of biological activities of this mediator, we determined the effect of PGE(2) released from MS on LPS-induced TNF-alpha release by murine peritoneal macrophages. We also analyzed the effect of encapsulated PGE(2) on inflammatory mediators release from HUVECs. Finally, we studied the effect of PGE(2) released from biodegradable MS in sepsis animal model. The use of this formulation can provide an alternative strategy for treating infections, by modulating or inhibiting inflammatory responses, especially when they constitute an exacerbated profile. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
The present study was designed to determine the prevalence and extended-spectrum beta-lactamase (ESBL) types in clinical isolates of Klebsiella spp. at a university hospital located in the Brazilian southern region (Ribeirao Preto, Sao Paulo) as well as their antibiotic susceptibility and genetic profiles. This study included 147 non-repeat Klebsiella spp. isolates collected from January to June 2000, of which 23 K. pneumoniae and 8 K. oxytoca were selected as ESBL producers by using the Oxoid combination disk method and Etest ESBL strip. beta-lactamases were characterized by IEF, PCR and sequencing assays using primers for ESBL genes. Antibiotic susceptibility was evaluated by MicroScan system. Dissemination of two major clones of ESBL-producing Klebsiella spp. occurred in the hospital. According to the results obtained in this study there was a clonal spread of CTX-M-producing K. oxytoca in five clinics and dissemination of ESBL-producing K. pneumoniae in the nursery and pediatrics wards.
Resumo:
Sickle cell disease (SCD) is an inherited disorder caused by a single nucleotide substitution in the P-globin gene. The clinical heterogeneity observed in SCD patients has been attributed to environmental and genetic factors. The patients are subjected to increased oxidative stress, particularly during vaso-occlusive crises and acute chest pain. Another possible cause of oxidative stress in SCD is the high concentration of iron in the patients` plasma. The increase in oxidative stress could be a relevant risk factor for mutagenesis and carcinogenesis. Studies on the frequency of basal chromosomal aberrations in cultured lymphocytes from SCD patients have not been reported so far. In order to contribute to the understanding of the role of the different biomarkers and their relationship with the extremely variable clinical manifestation of SCD, we investigated the frequency of chromosome damage in peripheral lymphocytes from sickle cells patients and healthy controls. We found an increased frequency of chromosome damage and percentage of aberrant metaphases in these patients when compared with control subjects, even at basal values (p < 0.05). In the cytogenetic sensitivity assay, the results showed that these patients presented a marked decrease in the mitotic index values compared with healthy controls. Cisplatin-induced chromosomal damage in lymphocytes from these patients was significantly higher than the frequency measured in healthy controls. The results obtained in the present study showed that more investigations are needed in order to elucidate the susceptibility to genomic instability of SCD patients.
Resumo:
Background: Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage. Methods: This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution. Discussion: The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.
Resumo:
The present study evaluates the in vitro and in vivo trypanocidal activity of ursolic acid and oleanolic acid against the Bolivia strain of Trypanosoma cruzi. Their acute toxicity is also assessed on the basis of median lethal dose (DL50) determination and quantification of biochemical parameters. Ursolic acid is the most active compound in vitro, furnishing IC50 of 25.5 mu M and displaying 77% of trypomastigote lysis at a concentration of 128 A mu M. In agreement with in vitro assays, the results obtained for the in vivo assay reveals that ursolic acid (at a dose of 20 mg/Kg/day) provides the most significant reduction in the number of parasites at the parasitemic peak. Results concerning the LD50 assay and the biochemical parameters evaluated in the present study demonstrate that these substances can be safely used on an experimental basis.
Resumo:
Histoplasmosis is a pulmonary disease characterised by chronic granulomatous and suppurative inflammatory reactions caused by Histoplasma capsulatum. Regarding new therapies to control fungal infections, the aim of this study was to investigate whether pulmonary administration of leukotriene B(4) (LTB(4))-loaded microspheres (MS) could confer protection to 5-lipoxygenase knockout (5-LO(-/-)) mice infected by H. capsulatum. In this study, MS containing LTB4 were administered intranasally to mice infected by H. capsulatum. On Day 14 after the infection, fungal recovery from the lungs and histology were evaluated and inflammatory cytokines were measured. Pulmonary administration of LTB(4)-loaded MS was able to reduce fungal recovery from infected lungs. Production of important inflammatory cytokines related to host defence was augmented following MS administration to the lungs. Lung histology also showed that infected mice presented a clear reduction in the fungal burden following the pulmonary release of LTB4 from MS. Our study provides evidence that the proposed biodegradable microparticulate system, which can release LTB4 to the lungs, can be employed as therapy, enhancing the antimicrobial activity of host cells during histoplasmosis. (C) 2009 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
Resumo:
Objective: The primary objective of this study was to evaluate the effect of a pharmaceutical care program on pharmacotherapy adherence in elderly diabetic and hypertensive patients. The clinical outcomes of this pharmacotherapy adherence approach were the secondary objective of the study. Setting: Public Primary Health Care Unit in a municipality in the Brazilian State of Sao Paulo. Method: A 36-month randomized, controlled, prospective clinical trial was carried out with 200 patients divided into two groups: control (n = 100) and intervention (n = 100). The control group received the usual care offered by the Primary Health Care Unit (medical and nurse consultancies). The patients randomized into the intervention group received pharmaceutical care intervention besides the usual care offered. Main outcome measure: Pharmacotherapy adherence (Morisky-Green test translated into Portuguese and computerized dispensed medication history) and clinical measurements (blood pressure, fasting glucose, A1C hemoglobin, triglycerides and total cholesterol) were evaluated at the baseline and up to 36 months. A P value < 0.05 was considered statistically significant. Results: A total of 97 patients from the intervention group and 97 patients from the control group completed the study (n = 194). Significant improvements in the pharmacotherapy adherence were verified for the intervention group according to the Morisky-Green test (50.5% of adherent patients at baseline vs. 83.5% of adherent patients after 36 months; P < 0.001) and the computerized dispensed medication history (52.6% of adherent patients at baseline vs. 83.5% of adherent patients after 36 months; P < 0.001); no significant changes were verified in the control group. Significant improvements in the number of patients reaching adequate values for their blood pressure (26.8% at baseline vs. 86.6% after 36-months; P < 0.001), fasting glucose (29.9% at baseline vs. 70.1% after 36 months; P < 0.001), A1C hemoglobin (3.3% at baseline vs. 63.3% after 36 months; P < 0.001), triglycerides (47.4% at baseline vs. 74.2% after 36 months; P < 0.001) and total cholesterol (59.8% at baseline vs. 80.4% after 36 months; P = 0.002) were verified in the intervention group, but remained unchanged in the control group. Conclusion: These results indicated the effectiveness of pharmaceutical care in improving pharmacotherapy adherence, with positive effects in the clinical outcomes of the patients studied.
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This paper analyzes the factors that influence the issuing price of debentures in Brazil in the period from year 2000 to 2004, applying a factor model, in which exogenous variables explain return and price behavior. The variables in this study include: rating, choice of index, maturity, country risk, basic interest rate, long-term and short-term rate spread, the stock market index, and the foreign exchange rate. Results indicate that the index variable, probability of default and bond`s maturity influence pricing and points out associations of long-term bonds with better rating issues. (C) 2008 Elsevier Inc. All rights reserved.