Environmental characteristics, nutritional and executive functions in children of 6 to 7 years / Características ambientais, funções nutricionais e executivas em crianças de 6 a 7 anos

Abstract This study aimed to analyze the socio-environmental characteristics, executive and nutritional functions in children aged 6 to 7 years, from public schools in Alagoas, Brazil. A quantitative, cross-sectional and descriptive study was performed involving 64 children of the mentioned age group, from public schools located in Alagoas: Maceió, on the coast; Major Isidoro, in the hinterland and Palmeira dos Índios, in the country. Such analyzes were made through the application of neuropsychological tests and anthropometric assessment with children and food and socio-environmental surveys with their parents. As for the type of housing, 100% were made of masonry, with a bathroom present in 98.4%. All children reported with the habit of bathing in the river / lagoon, presented some pathology. There was no significant difference between cities in terms of the sociodemographic characteristics evaluated, with the same result occurring with the factors associated with the occurrence of diseases in children. The subtests of WISC-IV, were below the average in all municipalities, and the TAC and SCC were classified within the average. However, even though the ranking were divided between below average and average, it is possible to identify from the subtests of WISC-IV, that the general IQ showed a cognitive level below the average. There was also no significant difference in the anthropometric assessment (weight, height, BMI and IMCI) between the evaluated students. The average weight was 23.3 kg to 25 kg, the height between 1.23 m to 1.24 m, the BMI between 16.4 to 17; the IMCI from 2.8 to 3.0. Children were classified within the average. Regarding micronutrients (Ca, Fe, K, Mg and Na, and vitamins A, C, D, B1, B9 and B12) and calories, there was also no significant difference between the cities evaluated. The same occurred with macronutrients (proteins, carbohydrates and lipids). This study showed that in general there was no difference between the students of the three municipalities. Probably, even though they are all public schools and from different cities, children have similar social conditions.

Resumo Este estudo teve como objetivo analisar as características socioambientais, funções executivas e nutricionais de crianças de 6 a 7 anos, de escolas públicas de Alagoas, Brasil. Foi realizado um estudo quantitativo, transversal e descritivo envolvendo 64 crianças, na referida faixa etária, de escolas públicas localizadas em Alagoas: Maceió, no litoral; Major Isidoro, no sertão e Palmeira dos Índios, no país. Tais análises foram feitas por meio da aplicação de testes neuropsicológicos e avaliação antropométrica com crianças e inquéritos alimentares e socioambientais com seus pais. Quanto ao tipo de habitação, 100% eram de alvenaria, com banheiro presente em 98,4%. Todas as crianças relataram o hábito de tomar banho no rio / lagoa, apresentavam alguma patologia. Não houve diferença significativa entre os municípios quanto às características sociodemográficas avaliadas, ocorrendo o mesmo resultado com os fatores associados à ocorrência de doenças em crianças. Os subtestes do WISC-IV, ficaram abaixo da média em todos os municípios, e o TAC e SCC foram classificados dentro da média. Porém, mesmo que a classificação tenha sido dividida entre abaixo da média e média, é possível identificar a partir dos subtestes do WISC-IV, que o QI geral apresentou um nível cognitivo abaixo da média. Também não houve diferença significativa na avaliação antropométrica (peso, altura, IMC e AIDPI) entre os alunos avaliados. O peso médio foi de 23,3 kg a 25 kg, a altura entre 1,23 ma 1,24 m, o IMC entre 16,4 a 17; A AIDPI de 2.8 a 3.0. As crianças foram classificadas dentro da média. Em relação aos micronutrientes (Ca, Fe, K, Mg e Na e vitaminas A, C, D, B1, B9 e B12) e calorias, também não houve diferença significativa entre os municípios avaliados. O mesmo ocorreu com os macronutrientes (proteínas, carboidratos e lipídios). Este estudo mostrou que de maneira geral não houve diferença entre os alunos dos três municípios. Provavelmente, mesmo sendo todas escolas públicas e de diferentes cidades, as crianças têm condições sociais semelhantes.

Environmental characteristics, nutritional and executive functions in children of 6 to 7 years / Características ambientais, funções nutricionais e executivas em crianças de 6 a 7 anos

This study aimed to analyze the socio-environmental characteristics, executive and nutritional functions in children aged 6 to 7 years, from public schools in Alagoas, Brazil. A quantitative, cross-sectional and descriptive study was performed involving 64 children of the mentioned age group, from public schools located in Alagoas: Maceió, on the coast; Major Isidoro, in the hinterland and Palmeira dos Índios, in the country. Such analyzes were made through the application of neuropsychological tests and anthropometric assessment with children and food and socio-environmental surveys with their parents. As for the type of housing, 100% were made of masonry, with a bathroom present in 98.4%. All children reported with the habit of bathing in the river / lagoon, presented some pathology. There was no significant difference between cities in terms of the sociodemographic characteristics evaluated, with the same result occurring with the factors associated with the occurrence of diseases in children. The subtests of WISC-IV, were below the average in all municipalities, and the TAC and SCC were classified within the average. However, even though the ranking were divided between below average and average, it is possible to identify from the subtests of WISC-IV, that the general IQ showed a cognitive level below the average. There was also no significant difference in the anthropometric assessment (weight, height, BMI and IMCI) between the evaluated students. The average weight was 23.3 kg to 25 kg, the height between 1.23 m to 1.24 m, the BMI between 16.4 to 17; the IMCI from 2.8 to 3.0. Children were classified within the average. Regarding micronutrients (Ca, Fe, K, Mg and Na, and vitamins A, C, D, B1, B9 and B12) and calories, there was also no significant difference between the cities evaluated. The same occurred with macronutrients (proteins, carbohydrates and lipids). This study showed [...].

Este estudo teve como objetivo analisar as características socioambientais, funções executivas e nutricionais de crianças de 6 a 7 anos, de escolas públicas de Alagoas, Brasil. Foi realizado um estudo quantitativo, transversal e descritivo envolvendo 64 crianças, na referida faixa etária, de escolas públicas localizadas em Alagoas: Maceió, no litoral; Major Isidoro, no sertão e Palmeira dos Índios, no país. Tais análises foram feitas por meio da aplicação de testes neuropsicológicos e avaliação antropométrica com crianças e inquéritos alimentares e socioambientais com seus pais. Quanto ao tipo de habitação, 100% eram de alvenaria, com banheiro presente em 98,4%. Todas as crianças relataram o hábito de tomar banho no rio / lagoa, apresentavam alguma patologia. Não houve diferença significativa entre os municípios quanto às características sociodemográficas avaliadas, ocorrendo o mesmo resultado com os fatores associados à ocorrência de doenças em crianças. Os subtestes do WISC-IV, ficaram abaixo da média em todos os municípios, e o TAC e SCC foram classificados dentro da média. Porém, mesmo que a classificação tenha sido dividida entre abaixo da média e média, é possível identificar a partir dos subtestes do WISC-IV, que o QI geral apresentou um nível cognitivo abaixo da média. Também não houve diferença significativa na avaliação antropométrica (peso, altura, IMC e AIDPI) entre os alunos avaliados. O peso médio foi de 23,3 kg a 25 kg, a altura entre 1,23 ma 1,24 m, o IMC entre 16,4 a 17; A AIDPI de 2.8 a 3.0. As crianças foram classificadas dentro da média. Em relação aos micronutrientes (Ca, Fe, K, Mg e Na e vitaminas A, C, D, B1, B9 e B12) e calorias, também não houve diferença significativa entre os municípios avaliados. O mesmo ocorreu com os macronutrientes (proteínas, carboidratos e lipídios). Este estudo mostrou que de maneira geral não houve diferença entre os alunos [...].

Environmental characteristics, nutritional and executive functions in children of 6 to 7 years

Abstract This study aimed to analyze the socio-environmental characteristics, executive and nutritional functions in children aged 6 to 7 years, from public schools in Alagoas, Brazil. A quantitative, cross-sectional and descriptive study was performed involving 64 children of the mentioned age group, from public schools located in Alagoas: Maceió, on the coast; Major Isidoro, in the hinterland and Palmeira dos Índios, in the country. Such analyzes were made through the application of neuropsychological tests and anthropometric assessment with children and food and socio-environmental surveys with their parents. As for the type of housing, 100% were made of masonry, with a bathroom present in 98.4%. All children reported with the habit of bathing in the river / lagoon, presented some pathology. There was no significant difference between cities in terms of the sociodemographic characteristics evaluated, with the same result occurring with the factors associated with the occurrence of diseases in children. The subtests of WISC-IV, were below the average in all municipalities, and the TAC and SCC were classified within the average. However, even though the ranking were divided between below average and average, it is possible to identify from the subtests of WISC-IV, that the general IQ showed a cognitive level below the average. There was also no significant difference in the anthropometric assessment (weight, height, BMI and IMCI) between the evaluated students. The average weight was 23.3 kg to 25 kg, the height between 1.23 m to 1.24 m, the BMI between 16.4 to 17; the IMCI from 2.8 to 3.0. Children were classified within the average. Regarding micronutrients (Ca, Fe, K, Mg and Na, and vitamins A, C, D, B1, B9 and B12) and calories, there was also no significant difference between the cities evaluated. The same occurred with macronutrients (proteins, carbohydrates and lipids). This study showed that in general there was no difference between the students of the three municipalities. Probably, even though they are all public schools and from different cities, children have similar social conditions.

Resumo Este estudo teve como objetivo analisar as características socioambientais, funções executivas e nutricionais de crianças de 6 a 7 anos, de escolas públicas de Alagoas, Brasil. Foi realizado um estudo quantitativo, transversal e descritivo envolvendo 64 crianças, na referida faixa etária, de escolas públicas localizadas em Alagoas: Maceió, no litoral; Major Isidoro, no sertão e Palmeira dos Índios, no país. Tais análises foram feitas por meio da aplicação de testes neuropsicológicos e avaliação antropométrica com crianças e inquéritos alimentares e socioambientais com seus pais. Quanto ao tipo de habitação, 100% eram de alvenaria, com banheiro presente em 98,4%. Todas as crianças relataram o hábito de tomar banho no rio / lagoa, apresentavam alguma patologia. Não houve diferença significativa entre os municípios quanto às características sociodemográficas avaliadas, ocorrendo o mesmo resultado com os fatores associados à ocorrência de doenças em crianças. Os subtestes do WISC-IV, ficaram abaixo da média em todos os municípios, e o TAC e SCC foram classificados dentro da média. Porém, mesmo que a classificação tenha sido dividida entre abaixo da média e média, é possível identificar a partir dos subtestes do WISC-IV, que o QI geral apresentou um nível cognitivo abaixo da média. Também não houve diferença significativa na avaliação antropométrica (peso, altura, IMC e AIDPI) entre os alunos avaliados. O peso médio foi de 23,3 kg a 25 kg, a altura entre 1,23 ma 1,24 m, o IMC entre 16,4 a 17; A AIDPI de 2.8 a 3.0. As crianças foram classificadas dentro da média. Em relação aos micronutrientes (Ca, Fe, K, Mg e Na e vitaminas A, C, D, B1, B9 e B12) e calorias, também não houve diferença significativa entre os municípios avaliados. O mesmo ocorreu com os macronutrientes (proteínas, carboidratos e lipídios). Este estudo mostrou que de maneira geral não houve diferença entre os alunos dos três municípios. Provavelmente, mesmo sendo todas escolas públicas e de diferentes cidades, as crianças têm condições sociais semelhantes.

Environmental characteristics, nutritional and executive functions in children of 6 to 7 years.

This study aimed to analyze the socio-environmental characteristics, executive and nutritional functions in children aged 6 to 7 years, from public schools in Alagoas, Brazil. A quantitative, cross-sectional and descriptive study was performed involving 64 children of the mentioned age group, from public schools located in Alagoas: Maceió, on the coast; Major Isidoro, in the hinterland and Palmeira dos Índios, in the country. Such analyzes were made through the application of neuropsychological tests and anthropometric assessment with children and food and socio-environmental surveys with their parents. As for the type of housing, 100% were made of masonry, with a bathroom present in 98.4%. All children reported with the habit of bathing in the river / lagoon, presented some pathology. There was no significant difference between cities in terms of the sociodemographic characteristics evaluated, with the same result occurring with the factors associated with the occurrence of diseases in children. The subtests of WISC-IV, were below the average in all municipalities, and the TAC and SCC were classified within the average. However, even though the ranking were divided between below average and average, it is possible to identify from the subtests of WISC-IV, that the general IQ showed a cognitive level below the average. There was also no significant difference in the anthropometric assessment (weight, height, BMI and IMCI) between the evaluated students. The average weight was 23.3 kg to 25 kg, the height between 1.23 m to 1.24 m, the BMI between 16.4 to 17; the IMCI from 2.8 to 3.0. Children were classified within the average. Regarding micronutrients (Ca, Fe, K, Mg and Na, and vitamins A, C, D, B1, B9 and B12) and calories, there was also no significant difference between the cities evaluated. The same occurred with macronutrients (proteins, carbohydrates and lipids). This study showed that in general there was no difference between the students of the three municipalities. Probably, even though they are all public schools and from different cities, children have similar social conditions.

Scent glands in legume flowers.

Scent glands, or osmophores, are predominantly floral secretory structures that secrete volatile substances during anthesis, and therefore act in interactions with pollinators. The Leguminosae family, despite being the third largest angiosperm family, with a wide geographical distribution and diversity of habits, morphology and pollinators, has been ignored with respect to these glands. Thus, we localised and characterised the sites of fragrance production and release in flowers of legumes, in which scent plays an important role in pollination, and also tested whether there are relationships between the structure of the scent gland and the pollinator habit: diurnal or nocturnal. Flowers in pre-anthesis and anthesis of 12 legume species were collected and analysed using immersion in neutral red, olfactory tests and anatomical studies (light and scanning electron microscopy). The main production site of floral scent is the perianth, especially the petals. The scent glands are distributed in a restricted way in Caesalpinia pulcherrima, Anadenanthera peregrina, Inga edulis and Parkia pendula, constituting mesophilic osmophores, and in a diffuse way in Bauhinia rufa, Hymenaea courbaril, Erythrostemon gilliesii, Poincianella pluviosa, Pterodon pubescens, Platycyamus regnellii, Mucuna urens and Tipuana tipu. The glands are comprised of cells of the epidermis and mesophyll that secrete mainly terpenes, nitrogen compounds and phenols. Relationships between the presence of osmophores and type of anthesis (diurnal and nocturnal) and the pollinator were not found. Our data on scent glands in Leguminosae are original and detail the type of diffuse release, which has been very poorly studied.

Association of serotonin transporter gene polymorphism 5HTTVNTR with osteoporosis.

AIM: To study the association of serotonin transporter gene polymorphisms and osteoporosis. MATERIAL AND METHODS: Blood samples were collected from 186 individuals with normal bone mineral density and 89 with osteoporosis. Serotonin transporter gene polymorphisms 5HTTVNTR and 5HTTLPR were studied by PCR and statistical analyses used to test the association between groups. RESULTS: The frequency of 12/10 and 12/12 genotypes of 5HTTVNTR was significantly higher among the osteoporotic patients (OR=2,620 CI 95% [1,112--6,172], P=0,037). For 5HTTLPR we did not find significant differences between the two studied groups. CONCLUSIONS: As far as we know, this is one of the few studies that report an association between 5HTTVNTR and osteoporosis opening the hypothesis that the determination of this specific serotonin transporter gene polymorphism may contribute to the identification of individuals at high risk for the development of osteoporosis.

IFN-gamma, but not nitric oxide or specific IgG, is essential for the in vivo control of low-virulence Sylvio X10/4 Trypanosoma cruzi parasites.

Highly virulent strains of Trypanosoma cruzi are frequently used as murine models of Chagas' disease. However, these strains do not fully represent the spectrum of parasites involved in the human infection. In this paper, we analysed parasitaemia, mortality, tissue pathology and parasite-specific IgG serum levels in immune-deficient mice infected with Sylvio X10/4 parasites, a T. cruzi derived from a chagasic patient that yields very low parasitaemias and in C3H/HePAS mice induces a chronic cardiopathy resembling the human disease. IFN-gamma was identified as a crucial element for parasite control as its absence determined a drastic increase in parasitaemia, tissue parasitism, leukocyte infiltrates at the heart and striated muscles and mortality. The lack of IFN-gamma or IL-12p40, a molecule shared by IL-12 and IL-23, also resulted in spinal cord lesions and a progressive paralysis syndrome. Whereas IgG2a was the main Ig isotype in infected C57BL/6 mice, IL-12p40-KO mice produced IgG2a and IgG1 and IFN-gamma-KO mice produced only IgG1. The IFN-gamma-protective effect was not essentially mediated by nitric oxide (NO), inasmuch as infected iNOS-KO mice showed no parasitaemia and low tissue damage. Mice deficient in CD4(+) or CD8(+) T cells showed an intermediate phenotype with increased mortality and tissue pathology but no parasitaemia. Interestingly, CD28-KO mice were unable to produce anti-T. cruzi IgG antibodies but presented moderate tissue pathology and managed to control the infection. Thus, differently from infections with high virulence parasites, neither IgG, NO nor CD28-mediated signalling are essential for the non-sterile control of Sylvio X10/4 parasites.

Diversity of Calliphoridae (Diptera) in Brazil's Tinguá Biological Reserve.

The Calliphoridae are flies of great ecological, medical and sanitary importance because they are decomposers of organic matter, mechanical vectors of pathogenic agents, and causers of myiasis. This paper attempts to ascertain the diversity of Calliphoridae in the Tinguá Biological Reserve and correlate meteorological data (temperature, relative humidity of the air, and precipitation) with the occurrence of these flies. The study was conducted at a site in the Tinguá Biological Reserve, located in the municipality of Nova Iguaçu, state of Rio de Janeiro, Brazil. Four traps were set up using chicken viscera as bait. The experiment was conducted over the period of May 2001 to April 2002, with two monthly collections. The captured flies were killed with ether and conserved in 70% alcohol and identified in the Laboratory of Diptera Studies (UNIRIO) and the Laboratory of Vector Insect Biology and Control (FIOCRUZ), both headquartered in the city of Rio de Janeiro, RJ, Brazil. A total of 1,987 insects were captured, 37.5% belonging to the family Calliphoridae, 29.4% to Muscidae, 16.0% to Sarcophagidae, and 17.1% to other families. The most representative species found was Phaenicia eximia (47.0%), followed by Hemilucilia semidiaphana (23.6%), Mesembrinella bellardiana (13.7%), Hemilucilia segmentaria (7.5%), Chloroprocta idioidea (4.9%), Chrysomya albiceps (1.2%), Chrysomya megacephala (0.9%), Phaenicia sericata (0.6%), Eumesembrinella sp. (0.5%), and Chrysomya putoria (0.1%). Large numbers of Calliphoridae were noted in May, June, September and January, coinciding with low rainfall and an average temperature of 21.8 to 27.0 degrees C. A negative correlation was found between the number of Calliphoridae captured and meteorological factors.

Diversity of Calliphoridae (Diptera) in Brazil's Tinguá Biological Reserve

Os califorídeos são dípteros de grande importância ecológica e médico-sanitário, em virtude de serem decompositores de matéria orgânica, vetores mecânicos de agentes patogênicos e causadores de miíases. O presente trabalho objetivou verificar a diversidade de califorídeos na Reserva Biológica do Tinguá e correlacionar os dados meteorológicos (temperatura, umidade relativa do ar e precipitação) com a ocorrência desses dípteros. O estudo foi realizado em uma localidade da Reserva Biológica do Tinguá, município de Nova Iguaçu. Foram instaladas quatro armadilhas de captura, utilizando como isca vísceras de frango. O experimento foi conduzido no período de maio/2001 a abril/2002, sendo realizadas duas coletas mensais. Os dípteros capturados foram sacrificados com éter, conservados em álcool 70% e sua identificação ocorreu no Laboratório de Estudo de Dípteros (UNIRIO) e no Laboratório de Biologia e Controle de Insetos Vetores (FIOCRUZ). Foram capturados 1987 insetos pertencentes às famílias Calliphoridae (37,5%), Muscidae (29,4%), Sarcophagidae (16,0%) e outras (17,1%). Phaenicia eximia foi a espécie mais representativa (47,0%), seguida por Hemilucilia semidiaphana (23,6%), Mesembrinella bellardiana (13,7%), Hemilucilia segmentaria (7,5%), Chloroprocta idioidea (4,9%), Chrysomya albiceps (1,2%), Chrysomya megacephala (0,9%), Phaenicia sericata (0,6%), Eumesembrinella sp. (0,5%), e Chrysomya putoria (0,1%). Observou-se um maior percentual de fêmeas (70,6%). Constatou-se elevada incidência de califorídeos em maio, junho, setembro e janeiro, coincidindo com baixa precipitação e temperatura média entre 21,8 e 27,0 ºC. Constatou-se uma correlação negativa entre o número de califorídeos capturados e os fatores meteorológicos.

Most parasite-specific CD8+ cells in Trypanosoma cruzi-infected chronic mice are down-regulated for T-cell receptor-alphabeta and CD8 molecules.

The present study shows that CD8+ T lymphocytes expressing low levels of T-cell receptor (TCR)alphabeta, CD8 and CD3 accumulate in the spleen, blood, peritoneum and liver, but not in the lymph nodes of mice chronically infected with Trypanosoma cruzi. Analysis of spleen lymphocytes reveals that most CD8LOW TCRLOW T cells have an experienced phenotype (CD44HIGH CD62LLOW and CD45RA,B,CLOW). These cells have small size, lack activation markers such as CD69, CD25 and CD11b (Mac-1), and do not spontaneously secrete cytokines, suggesting they are at the resting state. When stimulated in vitro with T. cruzi-infected macrophages, TCRLOW CD8LOW T cells behave as parasite-specific memory cells, readily responding with interferon-gamma (IFN-gamma) production. Indeed, among parasite-activated CD8+ lymphocytes, IFN-gamma production was mostly due to TCRLOW CD8LOW cells. Upon in vitro stimulation with anti-CD3/CD28 monoclonal antibodies, down-regulated cells produce IFN-gamma and tumour necrosis factor-alpha, but not interleukin IL-10 or IL-4. Our results indicate that despite parasite persistence, most T. cruzi-specific experienced CD8+ cells are resting. Nevertheless, when encountering infected macrophages these cells differentiate to Tc1 effectors.

Influence of acute-phase parasite load on pathology, parasitism, and activation of the immune system at the late chronic phase of Chagas' disease.

To obtain low and high parasite loads in the acute phase of Chagas' disease, A/J mice were infected with 10(3) or 10(5) Trypanosoma cruzi trypomastigotes of the Y strain and treated on day 6 with benznidazol. One year later, chronically infected mice were screened for subpatent parasitemias, tissue pathology, and immune response. Mice infected with the high parasite inoculum showed higher levels of chronic parasitemias, heart and striated muscle inflammation, and activation of the immune system than did mice infected with the low inoculum. Concerning the activation of the immune system, the main findings for high-dose-infected mice were (i) increased numbers of splenocytes, with preferential expansion of CD8(+) and B220(-) CD5(-) cells, many of them bearing a macrophage phenotype; (ii) higher frequencies of B (B220(+)), CD4(+), and CD8(+) large lymphocytes; (iii) a shift of CD4(+) cells towards a CD45RBLow phenotype; (iv) increased frequencies of both CD45RBLow and CD45RBHigh large CD4(+) cells; (v) augmented numbers of total immunoglobulin (Ig)-secreting cells, with predominance of IgG2a-producing cells; and (vi) increased production of gamma interferon and interleukin 4. In addition, these mice presented lower IgM and higher IgG2a and IgG1 parasite-specific serum antibody levels. Our results indicate that the parasite load at the acute phase of T. cruzi infection influences the activation of the immune system and development of Chagas' disease pathology at the late chronic phase of the disease.

Role of membrane-bound IgM in Trypanosoma cruzi evasion from immune clearance.

We have recently described that Trypanosoma cruzi parasites of the reticulotropic Y strain increase their resistance to antibody-induced clearance during their interaction with the vertebrate host immune system. In the present study, we observed that trypomastigotes of the myotropic CL strain isolated from normal host also display an increased resistance to immune clearance when compared to parasites obtained from immunosuppressed donors. Through fluorescence-activated cell sorting analysis, we have observed that the high expression of membrane-bound IgM antibodies on Y and CL trypomastigotes correlates with their enhanced resistance to Ig-induced clearance. Trypomastigotes from normal mice were essentially refractory to the in vitro binding of immunoglobulins, showing that their membrane structures were completely covered by IgM antibodies. These findings suggest that this isotype does not efficiently mediate immune clearance. Moreover, membrane-bound IgM antibodies limited the amount of IgG attached to the parasite and, as a consequence, impaired efficient immune clearance. Through this mechanism, trypomastigotes of T. cruzi could increase their persistence in the bloodstream thus favoring parasite transmission to its hematophagous host vector in the early acute phase of the disease.

[Effect of aluminum on the non-enzymatic oxidation of dopamine]. / Efeito do alumínio na oxidação não enzimática da dopamina.

The effect of different concentrations of aluminum sulphate on the nonenzymatic oxidation of dopamine was studied in order to evaluate the action of this metal on neuromelanin synthesis. Data shows that under the studied conditions, aluminum partially inhibits dopamine self-oxidation, decreasing the formation of some intermediate compounds, namely dopaminequinone and dopaminochrome. If neuromelanins have a cytoprotective function in the central nervous system, possibly acting as intracellular scavengers of free radicals and redox metal ions, their decrease due to aluminum could be responsible for serious damage to neuronal tissues.

[O2 generation during neuromelanin synthesis. The action of manganese]. / Geração de O2 durante a síntese de neuromelaninas. Acção do manganésio.

The oxygen uptake during the reaction of dopamine autoxidation was studied and it was found that it may occur through two distinct oxidative pathways. One involves the univalent reduction of oxygen, forming the superoxide radical, the other involves a bivalent reduction which generates hydrogen peroxide. The detection of the univalent reaction was followed by the study of oxygen consumption, in the presence of cytochrome c. The detection of the bivalent reaction was made in the presence of catalase. It was found that manganese increases the oxygen uptake of the reaction, by increasing the production of both oxygen active forms. It seems probable that the neurotoxicity of this metal may be related with the increased production of activated oxygen in dopaminergic neurons, which undergo an oxidative stress.

Resistance of Trypanosoma cruzi to blood clearance induced by acute-phase immune mouse serum.

To investigate functional changes in Trypanosoma cruzi parasites induced during their interaction with the vertebrate host, we compared the blood clearance profiles of blood forms isolated from infected normal mice (Reg-Tc) or from infected mice immunodepressed after treatment with cyclophosphamide (Cy-Tc). Parasite blood numbers were measured at various time intervals in animals injected intravenously (i.v.) with 1-2 x 10(6) T. cruzi of either isolate. In the absence of added immune sera (spontaneous clearance), Reg-Tc and Cy-Tc were cleared from blood at similar rates. However, when acute immune mouse serum (Ac-IMS) was injected i.v. 2 min after inoculation of parasites, a significant proportion of Cy-Tc only was cleared from the blood an hour later, whereas Reg-Tc were not, their clearance profile being identical to that observed in mice injected with normal mouse serum. Cy-Tc susceptibility to Ac-IMS was not the result of a toxic effect of cyclophosphamide over T. cruzi as parasites recovered from animals immunodepressed by irradiation before infection were cleared similarly by acute serum. Contrary to Ac-IMS, chronic immune mouse serum induced similar rates of disappearance of Reg-Tc and Cy-Tc from blood. Our results suggest the occurrence of T. cruzi selection or modification during the acute phase, which leads to an increased parasite resistance to the clearance properties of acute-phase antibodies.