RCAAP Repository

Conselho Nacional de Desenvolvimento Científico e Tecnológico

The venom of snakes from genus Bothrops contain toxin composed of several pharmacologically active substances, especially protein constituents, which act to induce local and systemic physiological changes in the body in which it is inoculated. Among the enzymatic component of the venoms are metalloproteinases, which are proteolytic enzymes zinc-dependents involved in the effects of ofidic envenoming. BmooMPα-I is a fibrin(ogen)olytic non-hemorrhagic enzyme isolated from B. moojeni snake venom. It shows a molecular mass of about 24.5 kDa, and belongs to the P-I class. In order to investigate its activity in relation to physiological processes, this work had as objective evaluated the BmooMPα-I influence in platelet aggregation and in inflammatory angiogenesis. The enzyme inhibited specifically the epinephrine-induced platelet aggregation when previously incubated with platelet rich plasma, not showing inhibition with ADP, collagen and ristocetin. Its activity is suppressed by denaturation, showing the dependence of the enzymatic action in the inhibition mechanism. About the inflammatory angiogenesis, our results showed that BmooMPα-I is an angiogenesis inhibitor.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The intake of energy excess and sedentary lifestyle are conditions associated with the development of obesity and resistance to insulin action. The origin of this resistance is tentatively explained by several theories, which include the theory of membrane resistance, whereby an excessive content of cholesterol would be a determinant of changes in the behavior of this cellular barrier, particularly in the transduction of hormonal signals. These changes in the membrane behavior would result from the excess supply of cholesterol and would occur in all cells of the human organism, with the greatest impact on myocytes, which are responsible for a significant consumption of glucose from the blood. The composition and behavior of the erythrocyte membrane is also influenced blood levels of cholesterol and glucose, such that these cells constitute a minimally invasive model to study the behavior of membranes in situations of energy homeostasis break, as occurs in obesity. The osmotic stability of the erythrocyte represents a representative property of the behavior of the cell membrane. It can be conveniently studied by analyzing the sigmoidal curve of the dependence of light absorbance of hemoglobin released in the lysis produced by a hypotonicity gradient. This curve can be adjusted to the Boltzmann equation, with determination of the salt concentration in the point of half transition (H50) and the variation in the concentration of salt required to promote the lysis transition (dX). The variables H50 and dX present inverse and direct relationships, respectively, with the osmotic stability of erythrocytes. The reason dX/H50 is a combined variable that presents a direct relation with the stability of erythrocyte membrane. In this study, the stability of erythrocytes was assessed before and after an activity program that included nutritional and psychological counseling, as well as four weekly sessions of aerobic and resistance exercises, lasting 30 minutes each session, for five months, in a population consisting of 44 adolescents (16 males and 28 females). To understand the interrelationships of the behavior of erythrocytes with variables subject to change during the training program established, were also evaluated anthropometric, hematological, biochemical, hormonal, and some biomarkers of organs and tissues integrity. The study ended with 21 adolescents (8 males and 13 females). At the end of the program of training, there was a decrease in all anthropometric variables considered (body mass, body mass index, waist circumference and fat content); an increase of some of the hematological variables [hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV) and distribution width of red blood cells (RDW)]; a reduction in blood lipids (total cholesterol, VLDL-C and triglycerides); elevation in the blood levels of creatinine and sodium and decrease in the potassium levels; elevation in the blood concentrations of total and direct bilirubin and decreased activity of γ-glutamyl transferase (γGT); decreased levels of thyroid stimulating hormone (TSH) and elevated levels of free thyroxine (FT4) and follicle- stimulating hormone (FSH); and increased stability of erythrocytes. A cross-sectional treatment of the correlations between the variables of stability and each of the variables analyzed in the study showed that: 1) the values of H50 increased with increase in hemoglobin, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), sodium and luteinizing hormone (LH) and decreased with increasing levels of glycated hemoglobin (Hb1C); 2) the values of dX decreased with increase in RBC, Hb, MCH, MCHC, VLDL-C, Tg, urea, creatinine, potassium and cortisol, and increased with increase in RDW; 3) the values of dX/H50 maintained the same pattern of dX correlations, except for urea and creatinine levels. These results suggest that the increased stability of erythrocytes after the training program was driven by an increase in RDW, since this was the only parameter that showed a direct relationship with dX/H50, and perhaps by decreasing levels of Hb1C, which was the only parameter that showed an inverse relationship with H50, although the decline in Hb1C after the training program was not statistically significant.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

ABSTRACT - I The stability of a biological membrane depends on its biochemical composition. The membranes are formed by a lipid bilayer where proteins are integrally or peripherically embedded. The intrinsic stabilities of the lipid bilayer and membrane proteins will determine the overall stability of the membrane. In this literature review, we discuss some factors that can affect the membrane stability, as the nature of the fatty acids present in the membrane lipids and the effect of chaotropic and stabilizing solutes. An emphasis is given to the action of ethanol on the biological membranes. ABSTRACT - II Amostras de sangue provenientes de 12 voluntários do gênero masculino (20-28 anos) foram incubadas com 0 a 34 g.dl-1 de etanol e estudadas por espectrofotometria e microscopia de luz. Em 1.56 g.dl-1 de etanol os eritrócitos foram visualizados em um estado intacto ou expandido (R), e em 25 g.dl-1 de etanol, os eritrócitos apareceram em um estado contraído ou apertado (T), embora algumas estruturas sofreram ruptura nesta concentração de etanol. A dependência da percentagem de hemólise com a concentração de etanol mostrou três transições de natureza sigmoidal em toda extensão da concentração de etanol: uma desnaturação (D50R), uma estabilização (S50) e outra transição de desnaturação (D50T), com seus respectivos pontos médios em 11,17±0,078 (D50R), 20,73±0,056 (S50) e 27,20±0,097 g.dl-1 (D50T) de etanol em 0.9% de NaCl. A incubação com 0.6% de NaCl alterou os valores de D50R, S50 e o D50T para 10,35±0,25 (P<0,001), 21,48±0,034 (P<0,001) e 31,27±1,490 (P<0,05) g.dl-1, respectivamente. A diminuição do D50R produzida pelo decréscimo da concentração de NaCl indica que esta transição de desnaturação é devida somente à ação caotrópica do etanol. O aumento produzido em S50 e D50T indica que a estabilização e transição da desnaturação do estado T têm origem no aumento da pressão osmótica. A origem termodinâmica do efeito estabilizante do etanol sobre os eritrócitos foi explicada com base na teoria da hidratação preferencial.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

A novel electrochemical genosensor with modified graphite with poly(4-aminophenol) has been constructed for detection of neuroblastoma, a malignant tumor originating from embryonic precursor cells of the sympathetic nervous system and associated with the amplification MYCN oncogene. The produced genosensor exhibited distinct electric and morphological properties using rhodamine b, specie able to bind with DNA duplex, as indicator of the hybridization process. The detection limit was evaluated to be 0.47 umol.L-1 (N=3) and showed very high selectivity for the complementary DNA using serum sample. This DNA sensing platform was successfully applied to detect the MYCN, an important biomarker for neuroblastoma