Belo Horizonte, Brazil
Belo Horizonte, Brazil

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Stahl P.,University of Marburg | Ruppert V.,University of Marburg | Meyer T.,University of Marburg | Meyer T.,University of Gottingen | And 11 more authors.
Apoptosis | Year: 2013

The haemoflagellate Trypanosoma cruzi is the causative agent of Chagas' disease that occurs in approximately 8 million people in Latin America. Patients infected with T. cruzi frequently suffer of cardiomegaly and may die of myocardial failure. Here we show that T. cruzi trypomastigotes (extracellular form) increased in vitro apoptosis of rat cardiomyocytes. Additionally, we demonstrated that amastigotes (intracellular form), for which a method for purification was established, were also able to induce cardiomyocyte apoptosis. Increase of apoptosis was associated with up-regulation of the apoptotic gene bax by trypomastigotes, while expression of the anti-apoptotic gene bcl-2 was down-regulated by amastigotes. The transcription factor STAT3 but not STAT1 was activated in cardiomyocytes by trypomastigotes. In addition, tlr7 gene expression was up-regulated in cardiomyocytes incubated with trypomastigotes, suggesting that this Toll-like receptor is involved in the intracellular recognition after host cell invasion by T. cruzi. Glycosylphosphatidylinositols purified from trypomastigotes did not induce cardiomyocyte apoptosis and STAT activation but down-regulated tlr7 gene expression. In conclusion, cardiomyopathy observed in Chagas' disease might be in part due to apoptosis of cardiomyocytes induced directly by the parasite. © 2013 Springer Science+Business Media New York.


PubMed | Federal University of Säo João del Rei and Research Center Rene Rachou
Type: Journal Article | Journal: Revista brasileira de epidemiologia = Brazilian journal of epidemiology | Year: 2014

The objective of this study was to examine the association between individual satisfaction with social and physical surroundings and the habit of smoking cigarettes. Data from the Health Survey of Adults from the metropolitan area of Belo Horizonte, Minas Gerais, Brazil, were used. Based on a probability sample, participants (n = 12,299) were selected among residents aged 20 years old or more. The response variable was the smoking habit and the explanatory variable of interest was the neighborhood perception. Potential confounding variables included demographic characteristics, health behaviors and other indicators of socioeconomic position. The prevalence of current smokers, former smokers and never smokers were 20.8, 14.1 and 65.1%, respectively; 74.4 and 25.5% of the participants were categorized as being more satisfied and less satisfied with the neighborhood, respectively. Compared to those who never smoked, former smokers (adjusted odds ratio = 1.40, 95% confidence interval 1.20 - 1.62) and current smokers (adjusted odds ratio = 1.17, 95% confidence interval 1.03 - 1.34) were less satisfied with the neighborhood compared to those who never smoked. The results of this study indicate there is an independent association between the smoking habit and a less satisfying neighborhood perception in the metropolitan region of Belo Horizonte, which does not depend on individual characteristics, traditionally reported as being associated with smoking.


PubMed | Federal University of Minas Gerais, Research Center Rene Rachou, Federal University of Juiz de fora, Superintendencia de Controle de Endemias do Estado de Sao Paulo SUCEN and Chacara Santa Ines
Type: Journal Article | Journal: PloS one | Year: 2014

Studies performed in the last 30 years demonstrated that a strain of B. tenagophila from the Taim Biological Reserve is completely resistant to Schistosoma mansoni infection. This resistance to parasite infection is a dominant characteristic during crossbreeding with susceptible B. tenagophila strains. These experiments also identified a 350 bp molecular marker that is exclusive to the Taim strain and does not occur in other geographic strains of this snail species. The Taim strain (Taim/RS) of Biomphalaria tenagophila was bred on a large scale, physically marked and introduced into a stream in which previous malacological analyses had revealed the presence of only parasite-susceptible B. tenagophila. Samples of offspring captured 4, 11 and 14 months after the introduction of the Taim strain were examined, and the susceptibility of the snails to S. mansoni infection dropped from 38.6-26.5% to 2.1% during the 14 months after the introduction of the Taim snail strain. A significant correlation was also observed between the absence of infection and the identification of the Taim molecular marker. These results demonstrate that the genetic marker from the Taim strain was successfully introduced into the wild snail population. In addition, a significant relationship exists between the marker and resistance to infection.


Marques D.P.D.A.,Research Center Rene Rachou | Rosa F.M.,Federal University of Juiz de fora | Maciel E.,Chacara Santa Ines | Negrao-Correa D.,Federal University of Minas Gerais | And 4 more authors.
PLoS ONE | Year: 2014

Studies performed in the last 30 years demonstrated that a strain of B. tenagophila from the Taim Biological Reserve is completely resistant to Schistosoma mansoni infection. This resistance to parasite infection is a dominant characteristic during crossbreeding with susceptible B. tenagophila strains. These experiments also identified a 350 bp molecular marker that is exclusive to the Taim strain and does not occur in other geographic strains of this snail species. The Taim strain (Taim/ RS) of Biomphalaria tenagophila was bred on a large scale, physically marked and introduced into a stream in which previous malacological analyses had revealed the presence of only parasite-susceptible B. tenagophila. Samples of offspring captured 4, 11 and 14 months after the introduction of the Taim strain were examined, and the susceptibility of the snails to S. mansoni infection dropped from 38.6-26.5% to 2.1% during the 14 months after the introduction of the Taim snail strain. A significant correlation was also observed between the absence of infection and the identification of the Taim molecular marker. These results demonstrate that the genetic marker from the Taim strain was successfully introduced into the wild snail population. In addition, a significant relationship exists between the marker and resistance to infection. © 2014 Marques et al.


Naumann G.B.,Ezequiel Dias Foundation | Silva L.F.,Ezequiel Dias Foundation | Silva L.,Ezequiel Dias Foundation | Faria G.,Ezequiel Dias Foundation | And 9 more authors.
Biochimica et Biophysica Acta - General Subjects | Year: 2011

Background: Multifunctional l-amino acid oxidases (LAAOs) occur widely in snake venoms. Methods: The l-AAO from Bothrops leucurus (Bl-LAAO) venom was purified using a combination of molecular exclusion and ion-exchange chromatographies. We report some biochemical features of Bl-LAAO associated with its effect on platelet function and its cytotoxicity. Results: Bl-LAAO is a 60 kDa monomeric glycoprotein. Its N-terminal sequence shows high homology to other members of the snake-venom LAAO family. Bl-LAAO catalyzes oxidative deamination of l-amino acids with the generation of H2O2. The best substrates were: l-Met, l-Norleu, l-Leu, l-Phe and l-Trp. The effects of snake venom LAAOs in hemostasis, especially their action on platelet function remain largely unknown. Bl-LAAO dose-dependently inhibited platelet aggregation of both human PRP and washed platelets. Moreover, the purified enzyme exhibited a killing effect in vitro against Leishmania sp., promastigotes, with a very low EC50 of 0.07 μM. Furthermore, the cytotoxicity of Bl-LAAO was observed in the stomach cancer MKN-45, adeno carcinoma HUTU, colorectal RKO and human fibroblast LL-24 cell lines. The enzyme released enough H 2O2 in culture medium to induce apoptosis in cells in a dose- and time-dependent manner. The biological effects were inhibited by catalase. Conclusion: Bl-LAAO, a major component of B. leucurus venom, is a cytotoxin acting primarily via the generation of high amounts of H 2O2 which kill the cells. General significance: These results allow us to consider the use of LAAOs as anticancer agents, as tools in biochemical studies to investigate cellular processes, and to obtain a better understanding of the envenomation mechanism. © 2011 Elsevier B.V. All rights reserved.


PubMed | Research Center Rene Rachou and Secretariat of Health in State of Minas Gerais
Type: Journal Article | Journal: Revista brasileira de epidemiologia = Brazilian journal of epidemiology | Year: 2015

This exploratory study aimed to investigate the predisposing, enabling and health need characteristics associated with lack of medical visits in the last 12 months, among 23,620 elderly hypertensive and/or diabetic individuals.In this research, we used the theoretical behavioral model of Andersen and Newman for use of health services. The data analyzed were produced by the health supplement of the Brazilian National Household Survey (PNAD) 2008, nationwide. To identify the associations, we used the Poisson regression model, which estimates the prevalence ratios and confidence intervals of 95%, considering the significance level of 5%.The results showed that 10.6% of the study population did not consult the doctor in the period considered, and the prevalence was higher among hypertensive subjects (10.5%) than among diabetic ones (7.1%). The lack of medical consultation was negatively associated with female sex and increasing age (predisposing characteristics), with health insurance coverage (enabling characteristic), worse self-rated health, chronic health conditions selected and the presence of hypertension associated with diabetes (health needs), while the fact of living in the Northeast, North and Midwest appeared positively associated with the event under investigation.These results corroborate those observed in national and international studies and show evidence of inequality and inequity in the use of medical consultation for this population, based on the findings related to health plan coverage and geographic region.


Ferreira D.N.,Research Center Rene Rachou | Matos D.L.,Health in the State of Minas Gerais | Filho A.I.L.,Research Center Rene Rachou | Filho A.I.L.,Federal University of Minas Gerais
Revista Brasileira de Epidemiologia | Year: 2015

Objective: This exploratory study aimed to investigate the predisposing, enabling and health need characteristics associated with lack of medical visits in the last 12 months, among 23,620 elderly hypertensive and/or diabetic individuals. Methods: In this research, we used the theoretical behavioral model of Andersen and Newman for use of health services. The data analyzed were produced by the health supplement of the Brazilian National Household Survey (PNAD) 2008, nationwide. To identify the associations, we used the Poisson regression model, which estimates the prevalence ratios and confidence intervals of 95%, considering the significance level of 5%. Results: The results showed that 10.6% of the study population did not consult the doctor in the period considered, and the prevalence was higher among hypertensive subjects (10.5%) than among diabetic ones (7.1%). The lack of medical consultation was negatively associated with female sex and increasing age (predisposing characteristics), with health insurance coverage (enabling characteristic), worse self-rated health, chronic health conditions selected and the presence of hypertension associated with diabetes (health needs), while the fact of living in the Northeast, North and Midwest appeared positively associated with the event under investigation. Conclusion: These results corroborate those observed in national and international studies and show evidence of inequality and inequity in the use of medical consultation for this population, based on the findings related to health plan coverage and geographic region. © 2015, Assocaicao Brasileira de Pos, Gradacao em Saude Coletiva. All rights reserved.


Sarvel A.K.,Research Center Rene Rachou | Oliveira A.A.,Research Center Rene Rachou | Silva A.R.,Federal University of Ouro Preto | Lima A.C.L.,Federal University of Minas Gerais | Katz N.,Research Center Rene Rachou
PLoS Neglected Tropical Diseases | Year: 2011

Background: Various studies showed that chemotherapy can control schistosomiasis morbidity, but association of measures (water supply, sewage disposal and increase of socioeconomic conditions) is necessary for transmission control. Methodology/Principal Findings: A survey dealing with socioeconomic conditions, snail survey, contact with natural waters, and clinical and stool examinations was undertaken at an endemic area in the State of Minas Gerais, Brazil. The methodology used was the same for both evaluations (1981 and 2005). Four hundred and seventy-five out of 1,474 individuals studied in 1981 could be contacted. From these, 358 were submitted to stool examination, and 231 of them were clinically examined. Patients eliminating S. mansoni eggs in their stools were treated. The results showed that the prevalence rate in Comercinho, a municipality of the State of Minas Gerais, Brazil, was substantially reduced to 70.4% and 1.7% in 1981 and 2005, respectively, as well as the frequency of the hepatosplenic form (7% to 1.3%) after five treatments effectuated between 1981 and 1992. No other new case of this form was detected from 1981 onwards. Another important aspect to be considered was the improvement of people's living standard that occurred in the region after more than two decades' efforts (better housing, professional skill and adequate basic sanitation). Conclusion/Significance: The control of morbidity and very significant decrease of schistosomiasis transmission in an area until then considered as hyperendemic was possible by means of association of successive specific treatments of the local population, together with the construction of privies, water supply in the houses and improvement of socioeconomic conditions. © 2011 Sarvel et al.


Barcelos Morais Da Silveira A.,Federal University of Uberlandia | Barcelos Morais Da Silveira A.,Research Center Rene Rachou | De Oliveira E.C.,Federal University of Goais | Neto S.G.,Federal University of Goais | And 5 more authors.
Human Pathology | Year: 2011

Chagas disease is one of the most serious parasitic diseases of Latin America, with a social and economic impact far outweighing the combined effects of other parasitic diseases such as malaria, leishmaniasis, and schistosomiasis. In the chronic phase of this disease, the destruction of enteric nervous system components leads to megacolon development. Besides neurons, the enteric nervous system is constituted by enteric glial cells, representing an extensive but relatively poorly described population within the gastrointestinal tract. Several lines of evidence suggest that enteric glial cells represent an equivalent of central nervous system astrocytes. Previous data suggest that enteric glia and neurons are active in the enteric nervous system during intestinal inflammatory and immune responses. To evaluate whether these cells act as antigen-presenting cells, we investigated the expression of molecules responsible for activation of T cells, such as HLA-DR complex class II and costimulatory molecules (CD80 and CD86), by neurons and enteric glial cells. Our results indicate that only enteric glial cells of chagasic patients with megacolon express HLA-DR complex class II and costimulatory molecules, and hence they present the attributes necessary to act as antigen-presenting cells. © 2011 Elsevier Inc. All rights reserved.


Nascimento R.D.,Federal University of Minas Gerais | de Souza Lisboa A.,Federal University of Minas Gerais | Fujiwara R.T.,Federal University of Minas Gerais | Fujiwara R.T.,Research Center Rene Rachou | And 6 more authors.
Human Pathology | Year: 2010

Chagas disease is caused by infestation with the parasite Trypanosoma cruzi, and some patients who are serologically positive develop chronic megaesophagus, whereas others are symptom-free. Gastrointestinal form of Chagas disease involves an inflammatory invasion of the enteric plexuses and degeneration of enteric neurons and previous works related that enteroglial cells would be involved in enteric inflammatory responses. Because of this, the aims of this study were to determine the relation of enteroglial cells with the denervation process in chagasic patients with and without megaesophagus and seronegative individuals. Our results indicated that the innervation of the esophageal muscle was substantially reduced in patients with megaesophagus, but asymptomatic seropositive subjects were not different to seronegative controls. Besides, patients with megaesophagus had significant decreased of enteroglial cells labeled with S-100 and glial fibrillary acidic protein, whereas patients without megaesophagus presented an increased of both labels. We believe that enteroglial cells would operate a mechanism of defense in the enteric nervous system against the Trypanosoma cruzi infection, which could prevent the organ denervation and preserve the esophagus function. Crown Copyright © 2010.

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