José Carlos P de Mattos (original) (raw)

Papers by José Carlos P de Mattos

Toxicology Letters, 1998

Stannous chloride (SnCl 2) has been used in many sectors of human activities such as food manufac... more Stannous chloride (SnCl 2) has been used in many sectors of human activities such as food manufacturing and in nuclear medicine to produce radiopharmaceuticals labeled with technetium-99m (99m Tc). Due to its importance and genotoxic potentiality, we decided to evaluate the biological effect induced by a nuclear medicine kit, which includes SnCl 2 , in association with glucoheptonic acid (GHA) which is employed for brain and renal scintigraphies. These studies were carried out with the Escherichia coli AB1157 strain and the deoxyribonucleic acid (DNA) plasmid pUC 9.1. The experiments, with different concentrations of SnCl 2 and GHA, show an inverse relationship between both agents. When the GHA concentration was increased, the cellular inactivation induced by SnCl 2 was reduced, as measured by the number of viable cells. Moreover, GHA protects the DNA molecule against the damage induced by SnCl 2 .

Toxicology Letters, 2000

Stannous chloride (SnCl 2) is widely used in daily human life, for example, to conserve soft drin... more Stannous chloride (SnCl 2) is widely used in daily human life, for example, to conserve soft drinks, in food manufacturing and biocidal preparations. In nuclear medicine, stannous chloride is used as a reducing agent of Technetium-99m, a radionuclide used to label different cells and molecules. In spite of this, stannous chloride is able to generate reactive oxygen species (ROS) which can damage DNA. In this work, plasmid DNA (pUC 9.1) was incubated with SnCl 2 under different conditions and the results analyzed through DNA migration in agarose gel electrophoresis. Our data reinforce the powerful damaging effect induced by stannous ion and suggest that this salt can play a direct role in inducing DNA lesions.

$Research paper thumbnail of Assessment of DNA damage induced by extracts, fractions and isolated compounds of Davilla nitida and Davilla elliptica (Dilleniaceae)$

Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2010

Davilla nitida and Davilla elliptica (Dilleniaceae) are plants that occur predominantly in the ce... more Davilla nitida and Davilla elliptica (Dilleniaceae) are plants that occur predominantly in the cerrado region of South America. They are used in popular medicine to treat stomach diseases, diarrhea and swelling, particularly of the lymph nodes and testicles. Chemical investigation of these two plant species led to the identification of the compounds myricetin-3-O-␣-l-rhamnoside (myricitrin), quercetin-3-O-␣l-rhamnoside (quercitrin), myricetin, quercetin and gallic acid derivatives in the leaves of D. nitida and D. elliptica. Therefore, it was concluded that the two species of Davilla possess qualitatively similar chemical profiles. In the present study, the mutagenic and genotoxic potential of these plants and of their isolated compounds was tested in the Salmonella typhimurium assay (Ames test) with strains TA100, TA98, TA102 and TA97a, in the micronucleus test with peripheral blood cells of mice treated in vivo, and in plasmid DNA to analyze DNA strand-breaks. In the assessment of mutagenic potential by the Ames test, extracts from both plant species and a D. nitida ethyl-acetate fraction induced positive responses. On the other hand, none of the extracts showed genotoxic activity in the mouse cells. In the presence of metal ion, D. nitida and D. elliptica aqueous and ethyl-acetate fractions, as well as their isolated compounds, induced single-and double-strand-breaks in plasmid DNA in a cell-free system.

Molecules, 2012

Radiopharmaceuticals are employed in patient diagnostics and disease treatments. Concerning the d... more Radiopharmaceuticals are employed in patient diagnostics and disease treatments. Concerning the diagnosis aspect, technetium-99m (99m Tc) is utilized to label radiopharmaceuticals for single photon computed emission tomography (SPECT) due to its physical and chemical characteristics. 99m Tc fixation on pharmaceuticals depends on a reducing agent, stannous chloride (SnCl 2) being the most widely-utilized. The genotoxic, clastogenic and anegenic properties of the 99m Tc-MDP(methylene diphosphonate used for bone SPECT) and SnCl 2 were evaluated in Wistar rat blood cells using the Comet assay and micronucleus test. The experimental approach was to endovenously administer NaCl 0.9% (negative control), cyclophosphamide 50 mg/kg b.w. (positive control), SnCl 2 500 μg/mL or 99m Tc-MDP to animals and blood samples taken immediately before the injection, 3, and 24 h after (in the Comet assay) and 36 h after, for micronucleus test. The data showed that both SnCl 2 and 99m Tc-MDP-induced deoxyribonucleic acid (DNA) strand breaks in rat total blood cells, suggesting genotoxic potential. The 99m Tc-MDP was not able to induce a significant DNA strand breaks increase in in vivo assays. Taken together, the data presented here points to the formation of a complex between SnCl 2 in the radiopharmaceutical 99m Tc-MDP, responsible for the decrease in cell damage, compared to

Journal of Ethnopharmacology, 2005

Aloe vera is a tropical plant, known in Brazil as babosa and several reputable suppliers produce ... more Aloe vera is a tropical plant, known in Brazil as babosa and several reputable suppliers produce a stabilized aloe gel for topic use. Since people use Aloe vera topically, they could be exposed to solar ultraviolet light in addition and it might cause a cross damage effect between these agents. The aim of this work was to investigate the biological effects of Aloe vera pulp extract, associated or not to UVA radiation, on Escherichia coli-deficient repair mutants and plasmid DNA, in order to test its genotoxic potential. Data obtained from analysis of survival fractions, bacterial transformation and agarose gel electrophoresis suggest that Aloe vera has genotoxic properties, but it seems not to be able to damage the cell membrane.

Journal of Ethnopharmacology, 1999

Peumus boldus extract has been used in popular medicine in the treatment of biliar litiase, hepat... more Peumus boldus extract has been used in popular medicine in the treatment of biliar litiase, hepatic insufficiency and liver congestion. Its effects are associated to the substance boldine that is present in its extract. In the present work, we evaluated the influence of boldine both in: (i) the structural conformation of a plasmid pUC 9.1 through gel electrophoresis analysis; and in (ii) the survival of the strain of Escherichia coli AB1157 submitted to reactive oxygen species (ROS), generated by a Fenton like reaction, induced by stannous chloride. Our results show a reduction of the lethal effect induced by stannous chloride on the survival of the E. coli culture in the presence of boldine. The supercoiled form of the plasmid is not modified by stannous chloride in the presence of boldine. We suggest that the protection induced by boldine could be explained by its anti-oxidant mechanism. In this way, the boldine could be reacting with stannous ions, protecting them against the oxidation and, consequently, avoiding the generation of ROS.

Biochimie, 2002

The stannous ion, mainly the stannous chloride (SnCl(2)) salt form, is widely used as a reducing ... more The stannous ion, mainly the stannous chloride (SnCl(2)) salt form, is widely used as a reducing agent to label radiotracers with technetium-99m ((99m)Tc). These radiotracers can be employed as radiopharmaceuticals in nuclear medicine procedures. In this case, there is no doubt about absorption of this complex, because it is intravenously administered in humans, although biological effects of these agents have not been fully understood. In this work we used a bacterial system to study the cytotoxic potential of stannous chloride. It is known that SnCl(2) induces lesions that could be mediated by reactive oxygen species (ROS). We, thus, investigated the existence of cross-adaptive response between hydrogen peroxide (H(2)O(2)) and SnCl(2) and the role of the OxyR system known to promote cellular protection against oxidative damages. Here we describe the results obtained with prior treatment of different Escherichia coli strains with sub-lethal doses of H(2)O(2), followed by incubation with SnCl(2). Our data show that H(2)O(2) is capable of inducing cross-adaptive response against the lethality promoted by SnCl(2), suggesting the OxyR system participation through catalase, alkyl hydroperoxide reductase and superoxide dismutase enzymes

Biochemistry and Molecular Biology Education, 2004

Good quality scientific teaching depends on the ability of researchers to translate laboratory ex... more Good quality scientific teaching depends on the ability of researchers to translate laboratory experiments into high school and undergraduate classes, bridging the advanced and basic science with common knowledge. A fast‐growing field in biomedical sciences is oxidative stress, which has been associated to several diseases, including cancer and neurodegenerative disorders. We suggest herein a simple methodology for exploring DNA damage as an introductory pathway to these themes. The potential of natural or artificial products to induce DNA strand breaks can be easily tested in supercoiled plasmids incubated with selected products followed by agarose gel electrophoresis. This is designed to detect single and double strand breaks caused by reactive oxygen species generated by the products being tested. The altered topology of the damaged plasmid migrates slowly in the gel, creating a new band. We further introduce the quantitation of supercoiled DNA forms using densitometry of the gel...

Brazilian Archives of Biology and Technology, 2008

Reactive oxygen species (ROS) can induce lesions in different cellular targets, including DNA. St... more Reactive oxygen species (ROS) can induce lesions in different cellular targets, including DNA. Stannous chloride (SnCl2) is a ROS generator, leading to lethality in Escherichia coli (E. coli), with the base excision repair (BER) mechanism playing a role in this process. Many techniques have been developed to detect genotoxicity, as comet assay, in eukaryotic cells, and plasmid DNA agarose gel electrophoresis. In this study, an adaptation of the alkaline gel electrophoresis method was carried out to ascertain the induction of strand breaks by SnCl2 in bacterial DNA, from E. coli BER mutants, and its repair pathway. Results obtained show that SnCl2 was able to induce DNA strand breaks in all strains tested. Moreover, endonuclease IV and exonuclease III play a role in DNA repair. On the whole, data has shown that the alkaline gel electrophoresis assay could be used both for studying DNA strand breaks induction and for associated repair mechanisms.

Methanolic extracts obtained from different organs of Cleome rosea, collected from its natural ha... more Methanolic extracts obtained from different organs of Cleome rosea, collected from its natural habitat and from in vitropropagated plants, were submitted to in vitro biological assays. Inhibition of nitric oxide (NO) production by J774 macrophages and antioxidant effects by protecting the plasmid DNA from the SnCl 2-induced damage were evaluated. Extracts from the stem of both origins and leaf of natural plants inhibited NO production. The plasmid DNA strand breaks induced by SnCl 2 were reduced by extracts from either leaf or stem of both sources. On the other hand, root extracts did not show any kind of effects on plasmid DNA, and presented significant toxic effects to J774 cells. The results showed that C. rosea presents medicinal potential and that the acclimatization process reduces the plant toxicity both to plasmid DNA and to J774 cells, suggesting the use of biotechnology tools to obtain elite plants as source of botanical material for pharmacological and phytochemical studies.

Journal of Biomedicine and Biotechnology, 2010

Stannous chloride (SnCl2) and UVA induce DNA lesions through ROS. The aim of this work was to stu... more Stannous chloride (SnCl2) and UVA induce DNA lesions through ROS. The aim of this work was to study the toxicity induced by UVA preillumination, followed bySnCl2treatment.E. coliBER mutants were used to identify genes which could play a role in DNA lesion repair generated by these agents. The survival assays showed (i) Thenfomutant was the most sensitive toSnCl2; (ii) lethal synergistic effect was observed after UVA pre-illumination, plusSnCl2incubation, thenfomutant being the most sensitive; (iii) wild type andnfomutants, transformed with pBW21 plasmid (nfo+) had their survival increased following treatments. The alkaline agarose gel electrophoresis assays pointed that (i) UVA induced DNA breaks andfpgmutant was the most sensitive; (ii)SnCl2-induced DNA strand breaks were higher than those from UVA andnfomutant had the slowest repair kinetics; (iii)UVA+SnCl2promoted an increase in DNA breaks thanSnCl2and, again,nfomutant displayed the slowest repair kinetics. In summary, Nfo protec...