Exposure to Mycobacterium avium Decreases the Protective Effect of the DNA Vaccine pVAXhsp65 Against Mycobacterium tuberculosis-Induced Inflammation of the Pulmonary Parenchyma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Neonatal BCG Immunization Followed by DNAhsp65 Boosters: Highly Immunogenic but not Protective Against Tuberculosis - a Paradoxical Effect of the Vector?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Protective effects of yacon (Smallanthus sonchifolius) intake on experimental colon carcinogenesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Protective effects of beta-glucan extracted from Agaricus brasiliensis against chemically induced DNA damage in human lymphocytes

beta-Glucans (BGs) are polysaccharides that are found in the cell walls of organisms such as bacteria, fungi, and some cereals. The objective of the present study was to investigate the genotoxic and antigenotoxic effects of BG extracted from the mushroom Agaricus brasiliensis (=Agaricus blazei Murrill ss. Heinemann). The mutagenic activity of BG was tested in single-cell gel electrophoresis assays with human peripheral lymphocytes. In addition, the protective effects against the cooked food mutagen 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and (+/-)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), which is the main metabolite of B[a]P, and against ROS (H2O2)-induced DNA damage, were studied. The results showed that the compound itself was devoid of mutagenic activity, and that a significant dose-dependent protective effect against damage induced by hydrogen peroxide and Trp-P-2 occurred in the dose range 20-80 mu g/ml. To investigate the prevention of Trp-P-2-induced DNA damage, a binding assay was carried out to determine whether BG inactivates the amine via direct binding. Since no such interactions were observed, it is likely that BG interacts with enzymes involved in the metabolism of the amine.

Protective effect of beta-glucan extracted from Saccharomyces cerevisiae, against DNA damage and cytotoxicity in wild-type (k1) and repair-deficient (xrs5) CHO cells

A large number of functional foods, including those that contain P-glucan, have been shown to prevent the development of cancer and other chronic diseases. The aim of the present study was to elucidate its mechanism of action, as well as to understand its effects as an antigenotoxic, anticlastogenic agent, and to determine its capacity to preserve cell viability. The investigation was carried out in the CHO-k1 and CHO-xrs5 cell lines. The cytokinesis-blocked micronucleus assay indicated that the different doses of beta-glucan examined (5, 10, 20 and 40 mu g/ml) did not show clastogenic effects. In the CHO-k1 cell line, a chemopreventive effect could be observed in all the protocols tested: pre-treatment (% reduction of 35.0-57.3), simultaneous treatment (simple - 5 reduction of 19.7-55.6 and with pre-incubation - of 42.7-56.4) and post-treatment (% reduction of 17.9-37.6). This finding indicates mechanisms of action involving desmutagenesis and bio-antimutagenesis, albeit the latter having a lesser role. However, in the repair-deficient CHO-xrs5 cells, beta-glucan did not show a protective effect with post-treatment (% reduction of 2.96), thus supporting the involvement of bioantimutagenesis. The comet assay in CHO-k1 cells demonstrated that beta-glucan has neither a genotoxic nor an antigenotoxic effect. Cell viability tests indicated that beta-glucan preserves cell viability in both cell lines, preventing apoptotic events. These findings suggest that beta-glucan, when present in foods, could provide them with nutraceutical characteristics and act as a dietary supplement, or that P-glucan could be used in new drug development. (c) 2006 Elsevier Ltd. All rights reserved.

Investigation of cytotoxic, apoptosis-inducing, genotoxic and protective effects of the flavonoid rutin in HTC hepatic cells

Rutin is a flavonoid with antioxidant, vasodilatory, anti-inflammatory and immune-stimulating activities. To study the toxicity of rutin and its protective effect, this work investigated the cytotoxic, apoptosis-inducing, genotoxic and protective effects of rutin in HTC cells. In the MTT assay, the highest concentration tested (810 mu M) showed cytotoxicity after 72 h of treatment, where cell viability and cell proliferation was diminished. None of the concentrations of rutin tested induced apoptosis after 24 h treatment. The highest concentration of rutin after 24 h treatment induced DNA damage, shown in the comet assay, but did have a genotoxic effect in the micronucleus test. Rutin was tested against the pro-carcinogenic agent benzo(a)pyrene, at concentrations of 90, 270 and 810 mu M, and was found to reduce induced DNA damage significantly. This protective effect of rutin against a pro-carcinogen, suggests an important biological activity for this compound, which can contribute to human health through the diet. (C) 2010 Elsevier GmbH. All rights reserved.

Protective effects of beta-glucan extracted from barley against benzo[a]pyrene-induced DNA damage in hepatic cell HepG2

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Are the anticipatory trunk movements occurring during load-carrying activities protective or risky?

This study evaluated anteroposterior trunk movements and the time spent on activities of load-carrying to surfaces at different heights, among experienced and inexperienced individuals. Thirty-six healthy males (16 experienced and 20 inexperienced in load-carrying) had their trunk movements recorded by an electrogoniometer while transporting boxes (7 and 15 kg) to surfaces of variable heights (low, low intermediate, high intermediate and high). Longer time was spent on trunk flexion when carrying loads to low surfaces and on trunk extension when carrying to high surfaces (p<0.05). Differences in time spent on trunk flexion/extension were identified between loads, and between groups for the heavier load. There were no differences in flexion/extension amplitudes between groups or loads. Although unnecessary flexion/extension occurring prior to a task may increase the exposure of the trunk to risky movements, the amplitudes reported here were relatively small and seemed to have occurred to facilitate the final tasks.Relevance to industryLifting devices and technological assistance are increasingly available in industrial settings. However, distribution centers and delivery services represent new demands on workers and involve an expressive amount of manual handling and carrying activities. Thus, studies on carrying strategies are necessary as they can provide guidelines for safer activities. (C) 2007 Elsevier B.V. All rights reserved.

Protective effect of prior physical conditioning on relaxing response of corpus cavernosum from rats made hypertensive by nitric oxide inhibition

The aim of this work was to evaluate the influence of run training on the responsiveness of corpus cavernosum (CC) from rats made hypertensive by treatment with nitric oxide (NO) synthesis inhibitor. Wistar rats were divided into sedentary control (C-SD), exercise training (C-TR), N(omega)-nitro-L-arginine methyl ester (L-NAME) sedentary (LN-SD) and L-NAME trained (LN-TR) groups. The run training program consisted in 8 weeks in a treadmill, 5 days/week, each session lasted 60 min. L-NAME treatment (2 and 10mg/rat/day) started after 4 weeks of prior physical conditioning and lasted 4 weeks. Concentration-response curves were obtained for acetylcholine (ACh), sodium nitroprusside (SNP), sildenafil and BAY 41-2272. The effect of electrical field stimulation (EFS) on the relaxations responses of CC was evaluated. Run training prevented the arterial hypertension induced by L-NAME treatment (LN-SD: 135+/-2 and 141+/-2 mm Hg for both doses of L-NAME) compared to LN-SD groups (154+/-1 and 175+/-2 mm Hg, for 2 and 10 mg of L-NAME, respectively). Run training produced an increase in the maximal responses (E(max)) of CC for ACh (C-SD: 47+/-3; C-TR: 5271; and LN-TR: 53+/-3%) and SNP (C-SD: 8971; C-TR: 9871; and LN-TR: 95+/-1%). Both potency and E(max) for ACh were reduced in a dose of 10 mg of L-NAME, and run training restored the reduction of E(max) for ACh. No changes were found for BAY 41-2271 and sildenafil. Relaxing responses to EFS was reduced by L-NAME treatment that was restored by prior physical conditioning. In conclusion, our study shows a beneficial effect of prior physical conditioning on the impaired CC relaxing responses in rats made hypertensive by chronic NO blockade.

PROTECTIVE EFFECTS OF DILTIAZEM ON THE MECHANICAL PERFORMANCE OF THE HYPOXIC MYOCARDIUM

1. To determine whether diltiazem protects the hypoxic myocardium by reducing contractile work, we have compared the effects of diltiazem and quiescence on left ventricular (LV) papillary muscle subjected to hypoxia. Papillary muscles were obtained from male Charles River CD rats weighing 150-250 g.2. Four groups of muscles were studied: control (N = 6), non-stimulation (N = 10), diltiazem 10(-4) M (N = 6) and diltiazem 10(-4) M plus non-stimulation (N = 10).3. Isolated mt LV papillary muscles were studied in Krebs-Henseleit solution with a calcium concentration of 2.52 mM at 28-degrees-C while contracting isometrically at a stimulation rate of 0.2 Hz. Resting tension and active isometric tension were measured.4. Both diltiazem and quiescence significantly attenuated contracture tension during hypoxia (0.91 +/- 0.10 vs 2.26 +/- 0.49 g/mm2 for diltiazem vs control, and 0.55 +/- 0.18 vs 2.26 +/- 0.49 g/mm2 for quiescence vs control). Recovery of active tension was improved in the diltiazem groups during reoxygenation (4.16 +/- 0.42 vs 3.75 +/- 0.51, 3.53 +/- 0.15 vs 2.90 +/- 0.13, 5.84 +/- 0.33 vs 6.48 +/- 0.29 and 5.98 +/- 0.90 vs 7.67 +/- 0.68 g/mm2 for diltiazem, diltiazem non-stimulation, non-stimulation and control groups).5. The results suggest that the protective effect of diltiazem during hypoxia was due to the reduction in energy demand of the myocardium.

Amifostine protective effect on cisplatin-treated rat testis

Cisplatin is a potent drug used in clinical oncology but causes spermatogenesis damage. Amifostine is a drug used against toxicity caused by ionizing irradiation and chemotherapeutic drugs. Since cisplatin provokes fertility and induces germ cell apoptosis and necrosis, we proposed to evaluate the amifostine cytoprotective action on testes of cisplatin-treated rats. Thirty-day-old prepubertal Wistar rats received a single cisplatin dose of 5 mg/kg and were killed after 3, 6, and 12 hr. The hematoxylin-eosin stained testicular sections were submitted to histological, morphometric, and stereological analysis. The terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) method was used to label apoptotic cells. TUNEL-positive and TUNEL-negative germ cells with abnormal nuclear morphology (ANM) were scored. Significant alterations of greater part of the parameters occurred in the cisplatin-treated group (CE) compared to the group that received amifostine before the cisplatin-treatment (ACE); however, testicular weight and volume did not vary between these groups. Tubular diameter was reduced in CE in comparison to ACE rats, while interstitial tissue and lymphatic space volume and volume density were significantly higher in CE rats; interstitial testicular edema probably occurred in cisplatin-treated rats. CE rats showed important histological alterations, which were more accentuated than in ACE rats. The numerical densities of apoptotic germ cells and TUNEL-negative cells with ANM were lower in ACE than in CE rats. In conclusion, the amifostine previously administered to prepubertal rats reduced the testicular damage caused by cisplatin. We conclude that amifostine partially protected the rat seminiferous epithelium against cisplatin toxicity.

The characterisation of the protective film formed by benzotriazole on the 90/10 copper-nickel alloy surface in H2SO4 media

The nature of the protective film formed by benzotriazole (BTAH) on the surface of the 90/10 CuNi alloy in deaerated 0.5 mol L-1 H2SO4 solution containing Fe(III) ions as oxidant was investigated by weight-loss, calorimetric measurements, and by surface-enhanced Raman spectroscopy (SERS). The SERS measurements show that the protective film is composed by the [Cu(I)BTA](n), polymeric complex and that the BTAH molecules are also adsorbed on the electrode surface. A modification of the BET isotherm for adsorption of gases ill solids is proposed to describe the experimental results obtained from weight-loss experiments that suggest an adsorption in multilayers. Electrochemical studies of copper and nickel in 0.5 mol L-1 H2SO4 in presence and absence of BTAH have also been made as an aid to interpret the results. The calculated adsorption free energy of the cuprous benzotriazolate on the surface of the alloy is in accordance with the value for pure copper. (C) 2007 Elsevier Ltd. All rights reserved.