Tatiane Freitas - Academia.edu (original) (raw)

Papers by Tatiane Freitas

Journal of Burn Care & Research, 2008

The survival of skin flaps has great interest in many areas of Medicine. In practice, one of the ... more The survival of skin flaps has great interest in many areas of Medicine. In practice, one of the most important complications in the use of skin flaps is the tissue ischemia, which frequently results in widespread necrosis and failure of the proposed treatments. The objective of this study was to evaluate the possible benefits of eletroacupuncture stimulation of the points DU-14 (Dazhui), DU-2 (Yaoshu), and Liv-13 (Zhangmen) over the skin flap survival of Wistar rats after 8 days of treatment. Forty male Wistar rats were allocated into four groups with 10 animals each. They were submitted to a surgical procedure in which a dorsal skin flap measuring 10 x 4 cm was elevated and then sutured back with a plastic barrier between the flap and the donor site. During the following 8 days, one group received electro stimulation in two &amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;nonaccupoints&amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; whereas the other one had the accupoints DU-14 (Dazhui), DU-2 (Yaoshu), and Liv-13 (Zhangmen) stimulated. After this period, the rats were killed and flaps were appraised qualitative and quantitatively. Data were evaluated with analysis of variance and to establish significance Fisher&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s PLSD test was used when analysis of variance showed P &amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05. It was observed that electroacupuncture group presented a skin flap survival index remarkably larger than the others. It has also shown a better evolution during the 8 days PO, confirmed by the lowest rate of necrosis and absent area. In this experimental model, eletroacupuncture was an efficient method to preserve vitality and decrease dorsal skin flap necrosis on Wistar rats.

International Journal of Biological Macromolecules

The immobilization of the glucose/mannose-binding lectin from Concanavalia ensiformis seeds (ConA... more The immobilization of the glucose/mannose-binding lectin from Concanavalia ensiformis seeds (ConA) onto a monolayer made of a galactomannan extracted from Leucaena leucocephala seeds (GML), which was adsorbed onto – amino-terminated surfaces, was investigated by means of ellipsometry and atomic force microscopy. The mean thickness of GML monolayer, which polysaccharide consists of linear 1 → 4-linked β-d-mannopyranosil units partially substituted at C-6 by α-d-galactopyranosyl units, amounted to (1.5 ± 0.2) nm. ConA molecules adsorbed onto GML surfaces forming (2.0 ± 0.5) nm thick layers. However, in the presence of mannose the adsorption failed, indicating that ConA binding sites were blocked by mannose and were no longer available for mannose units present in the GML backbone. The GML film was also used as support for the adsorption of three serotypes of dengue virus particles (DENV-1, DENV-2 and DENV-3), where DENV-2 formed the thickest film (4 ± 2) nm. The adsorbed layer of DENV-2 onto ConA-covered GML surfaces presented mean thickness values similar to that determined for DENV-2 onto bare GML surfaces. The addition of free mannose units prevented DENV-2 adsorption onto ConA-covered GML films by ∼50%, suggesting competition between virus and mannose for ConA binding sites. This finding suggests that if ConA is also adsorbed to GML surface and its binding site is blocked by free mannose, virus particles are able to recognized GML mannose unities substituted by galactose. Interactions between polysaccharides thin films, proteins, and viruses are of great relevance since they can provide basis for the development of biotechnological devices. These results indicate that GML is a potential polysaccharide for biomaterials development, as those could involve interactions between ConA in immune system and viruses.

Biochemical and Biophysical Research Communications, 2006

This paper describes the purification and characterization of a new N-acetyl-d-glucosamine-specif... more This paper describes the purification and characterization of a new N-acetyl-d-glucosamine-specific lectin from Araucaria angustifolia (AaL) seeds (Araucariaceae) and its anti-inflammatory and antibacterial activities. AaL was purified using a combination of affinity chromatography on a chitin column and ion exchange chromatography on Sephacel-DEAE. The pure protein has 8.0 kDa (SDS–PAGE) and specifically agglutinates rabbit erythrocytes, effect that was independent of the presence of divalent cations and was inhibited after incubation with glucose and N-acetyl-d-glucosamine. AaL showed antibacterial activity against Gram-negative and Gram-positive strains, shown by scanning electron microscopy. AaL, intravenously injected into rats, showed anti-inflammatory effect, via carbohydrate site interaction, in the models of paw edema and peritonitis. This lectin can be used as a tool for studying bacterial infections and inflammatory processes.

Epilepsy & Behavior, 2009

Possible central nervous system effects of the gymnosperm lectin from Araucaria angustifolia seed... more Possible central nervous system effects of the gymnosperm lectin from Araucaria angustifolia seeds were studied in seizure and open field tests. Male Swiss mice were administered saline (control), lectin (0.1, 1, and 10 mg/kg), flumazenil (1 mg/kg), or diazepam (1 mg/kg) intraperitoneally. Lectin at the highest dose increased time to death in the pentylenetetrazole- and strychnine-induced seizure models as compared with control, but not in the pilocarpine model. In the open field test, lectin reduced locomotor activity at all doses tested, as did diazepam, when compared with control. These locomotor effects were reversed by flumazenil pretreatment. In conclusion, A. angustifolia lectin had a protective effect in the pentylenetetrazole- and strychnine-induced seizure models, suggestive of activity in the GABAergic and glycinergic systems, respectively, and also caused a reduction in animal movements, which was reversed by flumazenil, pointing to a depressant action mediated by a GABAergic mechanism.

Colloids and Surfaces B-biointerfaces, 2008

Formation of stable thin films of mixed xyloglucan (XG) and alginate (ALG) onto Si/SiO2 wafers wa... more Formation of stable thin films of mixed xyloglucan (XG) and alginate (ALG) onto Si/SiO2 wafers was achieved under pH 11.6, 50 mM CaCl2, and at 70 °C. XG–ALG films presented mean thickness of (16 ± 2) nm and globules rich surface, as evidenced by means of ellipsometry and atomic force microscopy (AFM), respectively. The adsorption of two glucose/mannose-binding seed (Canavalia ensiformis and Dioclea altissima) lectins, coded here as ConA and DAlt, onto XG–ALG surfaces took place under pH 5. Under this condition both lectins present positive net charge. ConA and DAlt adsorbed irreversibly onto XG–ALG forming homogenous monolayers ∼(4 ± 1) nm thick. Lectins adsorption was mainly driven by electrostatic interaction between lectins positively charged residues and carboxylated (negatively charged) ALG groups.Adhesion of four serotypes of dengue virus, DENV (1–4), particles to XG–ALG surfaces were observed by ellipsometry and AFM. The attachment of dengue particles onto XG–ALG films might be mediated by (i) H bonding between E protein (located at virus particle surface) polar residues and hydroxyl groups present on XG–ALG surfaces and (ii) electrostatic interaction between E protein positively charged residues and ALG carboxylic groups. DENV-4 serotype presented the weakest adsorption onto XG–ALG surfaces, indicating that E protein on DENV-4 surface presents net charge (amino acid sequence) different from E proteins of other serotypes. All four DENV particles serotypes adsorbed similarly onto lectin films adsorbed. Nevertheless, the addition of 0.005 mol/L of mannose prevented dengue particles from adsorbing onto lectin films. XG–ALG and lectin layers serve as potential materials for the development of diagnostic methods for dengue.

Journal of Structural Biology, 2005

Here, we report the crystallographic study of a lectin from Canavalia maritima seeds (ConM) and i... more Here, we report the crystallographic study of a lectin from Canavalia maritima seeds (ConM) and its relaxant activity on vascular smooth muscle, to provide new insights into the understanding of structure/function relationships of this class of proteins. ConM was crystallized and its structure determined by standard molecular replacement techniques. The amino acid residues, previously suggested incorrectly by manual sequencing, have now been determined as I17, I53, S129, S134, G144, S164, P165, S187, V190, S169, T196, and S202. Analysis of the structure indicated a dimer in the asymmetric unit, two metal binding sites per monomer, and loops involved in the molecular oligomerization. These confer 98% similarity between ConM and other previously described lectins, derived from Canavalia ensiformis and Canavalia brasiliensis. Our functional data indicate that ConM exerts a concentration-dependent relaxant action on isolated aortic rings that probably occurs via an interaction with a specific lectin-binding site on the endothelium, resulting in a release of nitric oxide.

PLOS Neglected Tropical Diseases, 2011

Background: Reactivation of chronic Chagas disease, which occurs in approximately 20% of patients... more Background: Reactivation of chronic Chagas disease, which occurs in approximately 20% of patients coinfected with HIV/ Trypanosoma cruzi (T. cruzi), is commonly characterized by severe meningoencephalitis and myocarditis. The use of quantitative molecular tests to monitor Chagas disease reactivation was analyzed.

BMC Structural Biology, 2007

Background: Lectins are mainly described as simple carbohydrate-binding proteins. Previous studie... more Background: Lectins are mainly described as simple carbohydrate-binding proteins. Previous studies have tried to identify other binding sites, which possible recognize plant hormones, secondary metabolites, and isolated amino acid residues. We report the crystal structure of a lectin isolated from Canavalia gladiata seeds (CGL), describing a new binding pocket, which may be related to pathogen resistance activity in ConA-like lectins; a site where a non-protein amino-acid, αaminobutyric acid (Abu), is bound.

O ruído ocupacional é considerado um risco físico bastante freqüente em quase todos os segmentos ... more O ruído ocupacional é considerado um risco físico bastante freqüente em quase todos os segmentos industriais e, desse modo, merece atenção especial por parte dos profissionais da saúde e segurança do trabalho. O presente estudo investigou a presença de queixas e alterações audiométricas em trabalhadores de indústrias madeireiras do interior de Rondônia. Participaram do estudo 16 trabalhadores de três indústrias, os quais foram submetidos a uma entrevista sobre a audição, bem como ao exame audiológico por meio da audiometria tonal liminar e da imitanciometria. Todos os participantes eram do gênero masculino, sendo que a maioria apresentava idade inferior a 25 anos e referiu não haver concluído o Ensino Fundamental. Queixas auditivas e uso de protetor auricular foram referidos pela metade da amostra. Os traçados audiométricos revelaram alteração na metade da amostra. Palavras-chave: ruído, audição, audiometria, saúde do trabalhador, indústria da madeira.