DEFAR - Artigos publicados em periódicos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531

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Autor: search.filters.author.Coelho, George Luiz Lins MachadoTem arquivos: Sim

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    Genetic ancestry is associated with systolic blood pressure and glucose in Brazilian children and adolescents.
    (2016) Queiroz, Erica Maria de; Barbosa, Priscila Oliveira; Candido, Ana Paula; Castro, Ieso de Miranda; Coelho, George Luiz Lins Machado; Leite, Tailce Moura; Pereira, Rinaldo Wellerson; Freitas, Renata Nascimento de
    Background: Studies in admixed populations show that the prevalence of obesity and related diseases, such as type 2 diabetes and hypertension, may vary by ethnic group. The aim of this study was to investigate the relationship of genetic ancestry with phenotypes associated with obesity in a sample of school children and adolescents from Ouro Preto, Minas Gerais. Methods: We used data from genetic ancestry of 189 individuals previously determined by 15 ancestry informative markers (AIMs), and segregated individuals into three ancestral groups (predominantly African (PAFR), predominantly mixed (PMIX), and predominantly European (PEUR)) using the proportion of ancestry. The ancestral groups were compared with mean values of anthropometric, clinical, biochemical, and demographic variables. The simple linear regression analysis was used to test whether differences in mean values of the dependent variables (blood pressure and glucose) between the ancestral groups were dependent on the other variables. Results: Our results show that the proportions of African (F = 144.2, P < 0.001), Amerindian (F = 15.5, P < 0.001) and European (F = 184.9, P < 0.001) ancestry differed significantly (P < 0.001) among the three ancestral groups. PAFR individuals had higher mean blood pressure (P ≤ 0.029) and glucose (P = 0.025) as compared to PEUR. In the linear regression model, the difference in systolic blood pressure (SBP) values remained significant in all models tested and independent of confounding variables (P ≤ 0.041). The difference in diastolic blood pressure values observed in PAFR and PEUR groups did not remain significant when the metabolic profile was included in the tested model (P = 0.097). The difference in glucose values was significant only between PMIX and PEUR groups and independent of the settings (P ≤ 0.037). Conclusion: The positive correlation between genetic ancestry and SBP and glucose in Brazilian children and adolescents suggests the need for special care in the subgroups of this population.
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    Derivation and external validation of a simple prediction model for the diagnosis of type 2 Diabetes Mellitus in the Brazilian urban population.
    (2009) Sousa, André Gustavo Pires de; Pereira, Alexandre da Costa; Marquezine, Guilherme Figueiredo; Nascimento Neto, Raimundo Marques do; Freitas, Silvia Nascimento de; Nicolato, Roney Luiz de Carvalho; Coelho, George Luiz Lins Machado; Rodrigues, Sérgio Lamego; Mill, José Geraldo; Krieger, José Eduardo
    A risk score model was developed based in a population of 1,224 individuals from the general population without known diabetes aging 35 years or more from an urban Brazilian population sample in order to select individuals who should be screened in subsequent testing and improve the efficacy of public health assurance. External validation was performed in a second, independent, population from a different city ascertained through a similar epidemiological protocol. The risk score was developed by multiple logistic regression and model performance and cutoff values were derived from a receiver operating characteristic curve. Model’s capacity of predicting fasting blood glucose levels was tested analyzing data from a 5-year follow-up protocol conducted in the general population. Items independently and significantly associated with diabetes were age, BMI and known hypertension. Sensitivity, specificity and proportion of further testing necessary for the best cutoff value were 75.9, 66.9 and 37.2%, respectively. External validation confirmed the model’s adequacy (AUC equal to 0.72). Finally, model score was also capable of predicting fasting blood glucose progression in non-diabetic individuals in a 5-year follow-up period. In conclusion, this simple diabetes risk score was able to identify individuals with an increased likelihood of having diabetes and it can be used to stratify subpopulations in which performing of subsequent tests is necessary and probably cost-effective.
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    Cardiovascular risk factors in children and adolescents living in an urban area of southeast of Brazil : Ouro Preto study.
    (2009) Cândido, Ana Paula Carlos; Benedetto, Raquel; Castro, Ana Paula Pereira; Carmos, Joseane Souza do; Nicolato, Roney Luiz de Carvalho; Nascimento Neto, Raimundo Marques do; Freitas, Renata Nascimento de; Freitas, Silvia Nascimento de; Caiaffa, Waleska Teixeira; Coelho, George Luiz Lins Machado
    This study aims to identify risk factors for cardiovascular disorders in schoolchildren living in Ouro Preto City, Brazil. A cross-sectional study was carried out in a population-based sampling of schoolchildren (6– 14 years old), randomly selected and stratified by the proportion of students according to age and gender in each schools of the city. Biochemical, clinical and anthropometric variables as well as physical activity and family history were used in a logistic regression model for obesity or arterial hypertension. Out of 780 schoolchildren sampled, the risk of obesity was greater in subjects presenting high triglyceride and low high density lipoprotein-cholesterol levels, and those whose parents were obese, whilst the risk of hypertension was high in obese subjects and those who presented low birth weight. It was observed that 44.4% of the schoolchildren were exposed to two or three cardiovascular disease (CVD) risk factors and 8.2% were exposed to four or six factors. These findings should be considered in preventive measures to reduce the future risk for CVD among schoolchildren in Brazil.
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    Activity of the new triazole derivative albaconazole against Trypanosoma (Schizotrypanum) cruzi in dog hosts.
    (2004) Guedes, Paulo Marcos da Matta; Urbina, Julio Alberto; Lana, Marta de; Afonso, Luís Carlos Crocco; Veloso, Vanja Maria; Tafuri, Washington Luiz; Coelho, George Luiz Lins Machado; Chiari, Egler; Bahia, Maria Terezinha
    Albaconazole is an experimental triazole derivative with potent and broad-spectrum antifungal activity and a remarkably long half-life in dogs, monkeys, and humans. In the present work, we investigated the in vivo activity of this compound against two strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas’ disease, using dogs as hosts. The T. cruzi strains used in the study were previously characterized (murine model) as susceptible (strain Berenice-78) and partially resistant (strain Y) to the drugs currently in clinical use, nifurtimox and benznidazole. Our results demonstrated that albaconazole is very effective in suppressing the proliferation of the parasite and preventing the death of infected animals. Furthermore, the parasitological, PCR, serological, and proliferative assay results indicated parasitological cure indices of 25 and 100% among animals inoculated with T. cruzi strain Y when they were treated with albaconazole at 1.5 mg/kg of body weight/day for 60 and 90 days, respectively. On the other hand, although albaconazole given at 1.5 mg/kg/day was very effective in suppressing the proliferation of the parasite in animals infected with the Berenice-78 T. cruzi strain, no parasitological cure was observed among them, even when a longer treatment period (150 doses) was used. In conclusion, our results demonstrate that albaconazole has trypanocidal activity in vivo and is capable of inducing radical parasitological cure, although natural resistance to this compound was also indicated. Furthermore, the compound can be used in long-term treatment schemes (60 to 150 days) with minimal toxicity and thus represents a potentially useful candidate for the treatment of human Chagas’ disease.
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    Effects of specific treatment on parasitological and histopathological parameters in mice infected with different Trypanosoma cruzi clonal genotypes.
    (2004) Toledo, Max Jean de Ornelas; Bahia, Maria Terezinha; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Alves, Cíntia Fontes; Martins, Helen Rodrigues; Cruz, Ruth Elizabeth; Tafuri, Washington Luiz; Lana, Marta de
    The goal of this study was to verify the effect of specific treatment on parasitological and histopathological parameters in mice experimentally infected with different Trypanosoma cruzi clonal genotypes. Twenty cloned stocks were selected, representative of the whole phylogenetic diversity of the protozoan and belonging to the clonal genotypes 19 and 20 (T. cruzi I) and 39 and 32 (T. cruzi II). The stocks were inoculated in 40 BALB/c mice divided into four groups: (i) treated with benznidazole, (ii) treated with itraconazole and (iii and iv) untreated control groups (NT) for each drug, respectively. Seven parameters related to parasitaemia curves and histopathological lesions were analysed. Four during the acute phase (AP) and three during both the AP and chronic phase (CP) of infection. Statistical comparison between benznidazole-treated and NT groups for the biological parameters showed significant differences for all genotypes. Benznidazole treatment led to lower patent period, maximum of parasitaemia, day of maximum parasitaemia and area under the parasitaemia curve for all genotypes analysed. Percentage of positive haemoculture during AP and CP was lower for genotypes 19 and 32. Tissue parasitism (TP) and inflammatory process (IP) during AP were lower for genotypes 19 and 32, respectively. In general, itraconazole treatment induced a smaller reduction in these same parameters between treated and NT animals in relation to benznidazole treatment. Our results indicate that phylogenetic divergence among T. cruzi clonal genotypes must be taken in account in chemotherapy and studies dealing with all aspects of the parasite and the disease.
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    Influence of the long-term Trypanosoma cruzi infection in vertebrate host on the genetic and biological diversity of the parasite.
    (2005) Veloso, Vanja Maria; Romanha, Alvaro José; Lana, Marta de; Murta, Silvane Maria Fonseca; Carneiro, Cláudia Martins; Alves, Cíntia Fontes; Borges, Erika Carime; Tafuri, Washington Luiz; Coelho, George Luiz Lins Machado; Chiari, Egler; Bahia, Maria Terezinha
    The influence of the long-term Trypanosoma cruzi infection in vertebrate host on the biological and genetic properties of the parasite was evaluated. Four T. cruzi isolates obtained from different chronic chagasic dogs infected with Berenice-78 T. cruzi strain during 2 and 7 years were comparatively analyzed. The long-term T. cruzi infection has led to alterations in parasitemia, virulence and pathogenicity of Be-78 strain for mice. These biological parameters varied from low to high in realation to the parental strain. Randomly amplified polymorphic DNA and isoenzyme profiles detected two distinct genetic groups of parasites. The first group included the parental strain and two T. cruzi isolates, and the second group the two other isolates. Interestingly, the isolates of the second group showed a reversibility of the genetic profile to the parental strain after 25 passages in mice. No correlation between the genetic groups and biological properties of the isolates was observed. Our findings confirmed the population heterogeneity of the Be-78 strain, and showed how differently it responds to the long-term infection in the same vertebrate hosts.
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    Impact of dual infections on chemotherapeutic efficacy in balb/c mice infected with major genotypes of trypanosoma cruzi.
    (2007) Martins, Helen Rodrigues; Silva, Rodrigo Moreira da; Valadares, Helder Magno Silva; Toledo, Max Jean de Ornelas; Veloso, Vanja Maria; Avelar, Danielle Marchetti Vitelli; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Bahia, Maria Terezinha; Martins Filho, Olindo Assis; Macedo, Andréa Mara; Lana, Marta de
    The aim of this work was to investigate the impact of dual infections with stocks of Trypanosoma cruzi major genotypes on benznidazole (BZ) treatment efficacy. For this purpose, T. cruzi stocks representative of the genetic T. cruzi lineages, displaying different susceptibilities to BZ, belonging to the major T. cruzi genotypes broadly dispersed in North and South America and important in Chagas’ disease epidemiology were used. Therapeutic efficacy was observed in 27.8% of the animals treated. Following BZ susceptibility classification, significant differences were observed in dual infections on the major genotype level, demonstrating that combinations of genotypes 19 39 and genotypes 19 32 led to a shift in the expected BZ susceptibility profile toward the resistance pattern. Analysis on the T. cruzi stock level demonstrated that 9 out of 24 dual infections shifted the expected BZ susceptibility profile compared with the respective single infections, including shifts toward lower and higher BZ susceptibilities. Microsatellite identification was able to identify a mixture of T. cruzi stocks in 7.7% of the T. cruzi isolates from infected and untreated mice (6.9%) and infected and treated but not cured mice (9.0%), revealing in some mixtures of BZ-susceptible and -resistant stocks that the T. cruzi stock identified after BZ treatment was previously susceptible in single infections. Considering the clonal structure and evolution of T. cruzi, an unexpected result was the identification of parasite subpopulations with distinct microsatellite alleles in relation to the original stocks observed in 12.2% of the isolates. Taken together, the data suggest that mixed infections, already verified in nature, may have an important impact on the efficacy of chemotherapy.
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    Persistence of PCR-positive tissue in benznidazole-treated mice with negative blood parasitological and serological tests in dual infections with Trypanosoma cruzi stocks from different genotypes.
    (2008) Martins, Helen Rodrigues; Moreira, Lílian Figueiredo; Silva, Jaquelline Carla Valamiel de Oliveira e; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Avelar, Danielle Marchetti Vitelli; Bahia, Maria Terezinha; Martins Filho, Olindo Assis; Macedo, Andréa Mara; Lana, Marta de
    Objectives: To assess different methodologies to better define an early post-therapeutic cure criterion after benznidazole treatment in BALB/c mice following mixed infection with dual Trypanosoma cruzi genotypes. Methods: According to the classical cure criteria, animals were classified as treated not cured (TNC 5 76.4%), treated cured (TC 5 12.5%) and dissociated (DIS 5 11.1%) using parasitological [fresh blood examination (FBE), blood culture (BC) and blood PCR] and serological methods [conventional serology (CS-ELISA) and non-conventional serology (NCS-FC-ALTA)]. Tissues were also evaluated by PCR. Results: FBE was able to detect patent parasitaemia in only 18.1% of TNC and therapeutic failure was detected in 79.1% and 97.2% of TNC by BC and blood PCR, respectively. CS-ELISA should not be used before 3 months after treatment since it may lead to false-negative results. At 3 months after treatment with benznidazole, NCS-FC-ALTA was more efficient for categorizing the groups of treated mice. In the TNC group, although a decreased frequency of PCR-positive tissue was observed in several host tissues, increased positivity was also observed, despite the T. cruzi genotype combination. All TC animals presented at least two positive tissue-PCR results. Conclusions: Our results confirm that NSC-FC-ALTA and blood PCR are the most suitable methods to early detect therapeutic failure in acute murine T. cruzi infection. Additionally, our data show that BC positivity is highly dependent upon the T. cruzi genotype combination. Moreover, our findings demonstrated that PCR tests performed on tissues from animals considered cured after benznidazole treatment still detected T. cruzi DNA, most probably indicating residual infection.
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    Immunogenicity in dogs of three recombinant antigens (TSA, LeiF and LmSTI1) potential vaccine for canine visceral leishmaniasis.
    (2005) Fujiwara, Ricardo Toshio; Vale, André Macedo; Silva, João Carlos França da; Costa, Roberto Teodoro da; Quetz, Josiane da Silva; Martins Filho, Olindo Assis; Reis, Alexandre Barbosa; Oliveira, Rodrigo Corrêa de; Coelho, George Luiz Lins Machado; Bueno, Lilian Lacerda; Bethony, Jeffrey Michael; Frank, Glen; Nascimento, Evaldo do; Genaro, Odair; Mayrink, Wilson; Reed, Steven G.; Campos Neto, Antonio
    Control of canine visceral leishmaniasis (VL) remains a difficult and serious problem mostly because there is no reliable and effective vaccine available to prevent this disease. A mixture of three recombinant leishmanial antigens (TSA, LeIF and LmSTI1) encoded by three genes highly conserved in the Leishmania genus have been shown to induce excellent protection against infection in both murine and simian models of cutaneous leishmaniasis. A human clinical trial with these antigens is currently underway. Because of the high degree of conservation, these antigens might be useful vaccine candidates for VL as well. In the present study, using the dog model of the visceral disease, we evaluated the immunogenicity of these three antigens formulated with two different adjuvants, MPL-SE® and AdjuPrime®. The results were compared with a whole parasite vaccine formulated with BCG as the adjuvant. In order to investigate if sensitization with the recombinant antigens would result in recognition of the corresponding native parasite antigens upon infection, the animals were exposed for four weeks after the termination of the immunization protocol with the recombinant antigens to a low number of L. chagasi promastigotes, an etiological agent of VL. Immune response was evaluated by quantitative ELISA in the animal sera before and after exposure to the viable parasites. Both antigen specific IgG1 and IgG2 antibody levels were measured. Immunization of dogs with the recombinant antigens formulated in either MPL-SE® or AdjuPrime® resulted in high antibody levels particularly to LmSTI1. In addition, this immunization although to low levels, resulted in the development of antibody response to the whole parasite lysate. Importantly, experimental exposure with low numbers of culture forms of L. chagasi promastigotes caused a clear boost in the immune response to both the recombinant antigens and the corresponding native molecules. The boost response was predominantly of the IgG2 isotype in animals primed with the recombinant antigens plus MPL-SE®. In contrast, animals primed with the recombinant antigens formulated in AdjuPrime® as well as animals vaccinated with crude antigen preparation responded with mixed IgG1/IgG2 isotypes. These results point to the possible use of this antigen cocktail formulated with the adjuvant MPL-SE® in efficacy field trials against canine VL.
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    IGF2, LEPR, POMC, PPARG, and PPARGC1 gene variants are associated with obesity-related risk phenotypes in Brazilian children and adolescents.
    (2015) Queiroz, Erica Maria de; Cândido, Ana Paula Carlos; Castro, Ieso de Miranda; Bastos, Alínia Quália Araújo; Coelho, George Luiz Lins Machado; Freitas, Renata Nascimento de
    Association studies of genetic variants and obesity and/or obesity-related risk factors have yielded contradictory results. The aim of the present study was to determine the possible association of five single-nucleotide polymorphisms (SNPs) located in the IGF2, LEPR, POMC, PPARG, and PPARGC1 genes with obesity or obesity-related risk phenotypes. This case-control study assessed overweight (n=192) and normal-weight (n=211) children and adolescents. The SNPs were analyzed using minisequencing assays, and variables and genotype distributions between the groups were compared using one-way analysis of variance and Pearson’s chi-square or Fisher’s exact tests. Logistic regression analysis adjusted for age and gender was used to calculate the odds ratios (ORs) for selected phenotype risks in each group. No difference in SNP distribution was observed between groups. In children, POMC rs28932472(C) was associated with lower diastolic blood pressure (P=0.001), higher low-density lipoprotein (LDL) cholesterol (P=0.014), and higher risk in overweight children of altered total cholesterol (OR=7.35, P=0.006). In adolescents, IGF2 rs680(A) was associated with higher glucose (P=0.012) and higher risk in overweight adolescents for altered insulin (OR=10.08, P=0.005) and homeostasis model of insulin resistance (HOMA-IR) (OR=6.34, P=0.010). PPARG rs1801282(G) conferred a higher risk of altered insulin (OR=12.31, P=0.003), and HOMA-IR (OR=7.47, P=0.005) in overweight adolescents. PARGC1 rs8192678(A) was associated with higher triacylglycerols (P=0.005), and LEPR rs1137101(A) was marginally associated with higher LDL cholesterol (P=0.017). LEPR rs1137101(A) conferred higher risk for altered insulin, and HOMA-IR in overweight adolescents. The associations observed in this population suggested increased risk for cardiovascular diseases and/or type 2 diabetes later in life for individuals carrying these alleles