The objective of this study was to more clearly define the relationship between body condition, plasma leptin and insulin-like growth factor-I (IGF-I) in stallions and geldings in moderate (5.0-5.5) versus fleshy (7.0-7.5) body condition. Data analyses of physical measurements showed that there was a difference for BCS (P<0.001) even though the fat group only achieved a mean BCS of 6.3 + 0.2 as compared with a mean BCS of 5.3 + 0.1 for the moderate group. Differences also existed for rump fat (P<0.05) and percent body fat (P<0.05) between BCS groups. Analysis of physical measurements revealed that there was no sex effect as geldings and stallions within each group were not significantly different. Analysis of plasma leptin concurred with previous reports as a difference (P<0.001) existed between the BCS groups. Mean leptin concentrations were 2.13 + 0.1 ng/ml for the fat group and 1.44 + 0.1 ng/ml for the moderate group. After normalization of the data, changes in leptin concentrations still revealed a significant difference (P<0.05) between BCS groups, yet no difference in leptin concentrations between stallions and geldings was seen. Dexamethasone (DEX) treatment on d 0 caused a subsequent 24 h rise in plasma leptin in both groups. Analysis of plasma IGF-I revealed no difference in IGF-I concentrations between BCS groups. Mean plasma IGF-I was 347.2 + 11.4 ng/ml for the fat group and 344.3 + 10.0 ng/ml for the moderate group. There was however a difference (P<0.05) between geldings and stallions. Geldings exhibited an overall mean plasma IGF-I concentration of 360.6 + 9.1 ng/ml with stallions exhibiting a mean IGF-I concentration of 329.1 + 12.1 ng/ml. The post DEX challenge rise seen with leptin was not evident when analyzing the change in plasma IGF-I concentrations. In conclusion, the data presented herein have provided a more accurate profile of circulating concentrations of leptin and IGF-I in stallions and geldings of moderate and fleshy body condition.

Made available in DSpace on 2011-05-04T12:42:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2009 / As crianças, sobretudo aquelas socialmente vulneráveis, são mais susceptíveis aos efeitos tóxicos da exposição ambiental aos agentes químicos. No processo de desenvolvimento, o sistema nervoso imaturo apresenta grande oportunidade de ação de contaminantes ambientais como o mercúrio (Hg), chumbo (Pb) e o manganês (Mn). Os objetivos desta investigação foram quantificar o grau de exposição ao Mn em crianças residentes nas proximidades de uma planta metalúrgica de ligas ferro-manganês e avaliar a associação entre os níveis deste metal no sangue e no cabelo e efeitos na função cognitiva. Para tal fim, foi realizada uma revisão da literatura científica sobre exposição de crianças ao Mn e efeitos neuropsicológicos, a qual originou o primeiro artigo. A avaliação da exposição ao Mn foi realizada na Vila Cotegipe, no município de Simões Filho, Bahia. Na primeira etapa do trabalho foram obtidas das crianças de 1 a 10 anos amostras de cabelo para determinação do Mn, sangue para hemograma e amostras para parasitológico de fezes. Foram também coletadas amostras ambientais como: água bruta e tratada, material particulado na fração respirável (PM2.5) e poeira domiciliar. Para fins de comparação, crianças de uma comunidade distante 7,5 km da metalúrgica, e a favor dos ventos, foram incluídas como grupo controle Na segunda etapa da avaliação, foram incluídas somente as crianças de 6 a 11 anos e 11 meses matriculadas na escola municipal local. Novas amostras de cabelo e sangue foram coletadas para análise de Mn, chumbo (Pb) e ferro sérico, sendo solicitada a mãe ou responsável a doação da amostra de cabelo. Nessa etapa foi realizada a avaliação cognitiva, através dos instrumentos WISC-III (Wechesler Intelligence Scale for Children), matriz progressiva de Raven para medir a cognição materna e inventário HOME adaptado para estimar o ambiente familiar. Os resultados das amostras ambientais mostraram que os teores de Mn na água estavam dentro dos padrões aceitáveis a concentração de Mn no ar (PM2.5) estava em média três vezes superior a concentração referência da EPA (RfC 0,05 μg/m3) e os níveis de Mn na poeira domiciliar estavam aproximadamente 20 vezes mais elevados do que os níveis deste na poeira em residências do grupo controle. Das 165 crianças elegíveis os pais de 147 delas concordaram com a participação no estudo e 109 (66,1%) aceitaram doar amostras biológicas. Os níveis de Mn no sangue estavam na maioria (97%) dentro dos valores normais (4-x14 μg/L); porém, tanto em 2007 como em 2008, os níveis de Mn no cabelo tiveram mediana de 9,70 μg/g (1,10-95,50) μg/g e 6,51 μg/g (0,10-76,78 μg/g), respectivamente, superando em muitas vezes a mediana encontrada na população controle 1,09 μg/g (0,30-5,58 μg/g). Os níveis de Mn no cabelo materno encontravam-se igualmente elevados 4,04 μg/g (0,10-77,75 μg/g). Foi observada uma associação significativa entre os níveis de Mn no cabelo da criança e decréscimo no QI na Escala Total, subescala Verbal e fatorial Compreensão, após ajuste pela escolaridade materna e índice nutricional. Foi possível demonstrar pela primeira vez que o Mn também interfere na cognição de adultos, pois as mães ou responsáveis apresentavam um significativo decréscimo de acordo com a concentração de Mn no cabelo, ajustado pela idade, renda familiar e grau de escolaridade. Nossos resultados comprovam que as crianças desta comunidade estão sujeitas a uma exposição excessiva ao Mn oriundas das emissões da metalúrgica, com possíveis conseqüências negativas no desenvolvimento intelectual. Devido aos efeitos observados nas mães, se pode pensar que essas crianças sejam duplamente afetadas pela exposição ao Mn, tanto de forma direta, resultante do efeito do Mn nos seus sistemas nervoso e outra indireta, devido ao seu efeito no intelecto materno, conduzindo a uma menor estimulação neuropiscológica da criança. / Children, especially those socially vulnerable, are more susceptible to toxic effects resulting from environmental exposure to chemical agents. The developing nervous system has great opportunities to the action of environmental contaminants like mercury (Hg), lead (Pb) and manganese (Mn). The objectives of this research were to evaluate the Mn exposure levels in children living in the vicinity of a ferro-manganese alloy plant and investigate the association between Mn levels in blood and hair with the effects on the cognitive function. Initially, we carried out an intensive literature review on the association between children's exposure to Mn and neuropsychological effects, which led to the first article. The field work started with the populational pool and registration of all families within the limits of the Cotegipe Village, Simões Filho town, Bahia, Brazil. After obtaining the informed consent, we collected socio-demographic data among the volunteers. To assess Mn exposure level, we performed the first sampling campaign with children aged 1 to 10 years: hair samples for Mn determination, blood sample for haemogram and stool for intestinal parasites analyses. At this phase we collected environmental samples: water pre a post treatment, particulate matter from respirable fraction (PM2.5) and house dust. In the second exposure assessment campaign we included only children aged 6 to 11 years and 11 months, enrolled in the local public school, who provided hair and blood samples for Mn, lead and serum iron determination. Mothers or caregivers were asked to provide hair sample. This happened concomitantly with the cognitive evaluation, which was assessed using WISC-III (Wechesler Intelligence Scale for Children), Raven's Progressive Matrices for measuring maternal cognition and the adapted HOME to estimate the family environment stimulation. The results of the environmental assessment showed that water Mn levels were within the acceptable standards, Mn concentrations in the air (PM2.5) were on average three times higher than the USEPA reference concentration (RfC 0.05 μg/m3) and Mn levels in house dust were approximately 20 times higher than levels of the house dust in residences distant 7.5 km (control). Of the 165 children enrolled, the parents of 147 agreed to participate in the study and 109 children (66.1%) consented to donate biological samples. Blood Mn levels were in the majority (97%) within the normal range (4-14 μg/L), however in the two campaigns conducted in 2007 and 2008, hair Mn level medians were 9.70 μg/g (1.10-95.50 μg/g) and 6.51 μg/g (0.1-76.78 μg/g), respectively. These levels were much higher than the median level observed in the control group 1.09 μg/g (0.30-5.58 μg/g). Maternal Mn hair levels were also elevated 4.04 μg/g (0.1-77.75 μg/g). We observed a significant association between Mn hair levels and a decreament in Full-Scale, Verbal and factorial Comprehension IQ scores, after adjusting for maternal education and nutritional index. It was possible to demonstrate for the first time that Mn interferes with maternal cognition as well. Cognitive function of mothers and caregivers presented a significant decrease with increasing Mn concentrations in hair, adjusted for age, family income and years of schooling. Our results show that children of this community are subjected to excessive Mn exposure from emissions arising from the industrial plant, with a consequent measurable negative effect on the intellectual development. Based on these findings we could hypothesize that these children are doubly affected, directly due to the Mn effect on their own brains and indirectly as a result of the effect on their mothers‘ cognition, which would tend to provide a poorer neuropsychological stimulation of their children.