Leukocytes respiratory burst and lysozyme level in pacu (Piaractus mesopotamicus Holmberg, 1887)

Respostas imunológicas inatas são úteis para determinar o estado de saúde de peixes e avaliar o efeito de substâncias imunomoduladoras no cultivo destes animais. A atividade respiratória de leucócitos foi medida em pacu (Piaractus mesopotamicus) através de ensaio de quimioluminescência e ensaio de redução do nitroblue tetrazolium (NBT). O ensaio de redução do nitroblue tetrazolium pareceu mais adequado que o ensaio de quimioluminescência para determinação da atividade respiratória de leucócitos, uma vez que foi difícil isolar com êxito os leucócitos do sangue para o ensaio de quimioluminescência. Lisozima sérica e plasmática foram medidas por meio de ensaio turbidimétrico. Com o objetivo de inativar as proteínas do sistema complemento, as amostras de soro e plasma foram aquecidas (56 ºC por 30 minutos). Porém, este procedimento provocou a turvação das amostras de plasma e interferiu nos resultados. A atividade de lisozima no soro foi maior que no plasma, sugerindo que amostras de soro são mais apropriadas para esta análise. Este estudo estabeleceu protocolos que podem ser utilizados como ferramentas no estudo de mecanismos imunológicos do peixe tropical pacu.

Profile of cortisol, glycaemia, and blood parameters of American Bullfrog tadpoles Lithobates catesbeianus exposed to density and hypoxia stressors

O objetivo deste estudo foi avaliar a resposta fisiológica (cortisol, glicemia e parâmetros sanguineos) de girinos de rã-touro (Lithobates catesbeianus) em diferentes densidades e após exposição aérea. Os animais utilizados no experimento estavam entre os estágios 31 a 39, na fase de pró-metamorfose sendo testados 1 girino/L (Tratamento 1), 5 girinos/L (Tratamento 2) e 10 girinos/L (Tratamento 3), conduzidos em 3 réplicas simultâneas durante 12 dias. O sangue foi retirado por rompimento do vaso caudal na condição de Normóxia - N (tempo zero) e Hipóxia - H (tempo de 15 minutos de exposição ao ar). Foi observado um aumento nos valores de cortisol, aos 4 e 8 dias de exposição aérea retornando aos valores basais ao final do experimento, apesar de não haver diferenças significativas. A glicemia não apresentou diferenças significativas quanto aos estressores aplicados. Os parâmetros hematológicos da série branca, principalmente, o número de linfócitos, neutrófilos e eosinófilos mostraram diferença significativa aos 12 dias de experimentação quando comparados com o momento zero; concluindo-se que, em condições controladas, o adensamento de até 10 girinos/litro e a exposição aérea por 15 minutos não apresentou danos aos girinos de rã-touro durante o período experimental. O padrão de resposta a estes estímulos talvez seja expresso em outro nível hormonal (corticosterona).

Balance ability in 7- and 10-year-old children:associations with prenatal lead and cadmium exposure and with blood lead levels in childhood in a prospective birth cohort study

OBJECTIVES: Most studies reporting evidence of adverse effects of lead and cadmium on the ability to balance have been conducted in high-exposure groups or have included adults. The effects of prenatal exposure have not been well studied, nor have the effects in children been directly studied. The aim of the study was to identify the associations of lead (in utero and in childhood) and cadmium (in utero) exposure with the ability to balance in children aged 7 and 10 years. DESIGN: Prospective birth cohort study. PARTICIPANTS: Maternal blood lead (n=4285) and cadmium (n=4286) levels were measured by inductively coupled plasma mass spectrometry in women enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) during pregnancy. Child lead levels were measured in a subsample of 582 of ALSPAC children at age 30 months. MAIN OUTCOME MEASURES: Children completed a heel-to-toe walking test at 7 years. At 10 years, the children underwent clinical tests of static and dynamic balance. Statistical analysis using SPSS V.19 included logistic regression modelling, comparing categories of ≥ 5 vs <5 µg/dL for lead, and ≥ 1 vs <1 µg/L for cadmium. RESULTS: Balance at age 7 years was not associated with elevated in utero lead or cadmium exposure (adjusted OR for balance dysfunction: Pb 1.01 (95% CI 0.95 to 1.01), n=1732; Cd 0.95 (0.77 to 1.20), n=1734), or with elevated child blood lead level at age 30 months (adjusted OR 0.98 (0.92 to 1.05), n=354). Similarly, neither measures of static nor dynamic balance at age 10 years were associated with in utero lead or cadmium exposure, or child lead level. CONCLUSIONS: These findings do not provide any evidence of an association of prenatal exposure to lead or cadmium, or lead levels in childhood, on balance ability in children. Confirmation in other cohorts is needed.

Macroglial and retinal changes in hypercholesterolemic rabbits after normalization of cholesterol levels

This study evaluates hypercholesterolemic rabbits, examining the retinal changes in Müller cells and astrocytes as well as their variations after a period of normal blood-cholesterol values induced by a standard diet. New Zealand rabbits were divided into three groups: G0, fed a standard diet; G1A, fed a 0.5% cholesterol-enriched diet for 8 months; and G1B, fed as G1A followed by standard diet for 6 months. Eyes were processed for transmission electron microscopy and immunohistochemistry (GFAP). While G1B resembled G0 more than did G1A, they shared alterations with G1A: a) as in G1A, Müller cells were GFAP+, filled spaces left by axonal degeneration, formed glial scars and their nuclei were displaced to the nerve-fibre layer. The area occupied by the astrocytes associated with the nerve-fibre bundles (AANFB) and by perivascular astrocytes (PVA) in G1A and G1B was significantly lower than in controls. However, no significant differences in PVA were found between G1A and G1B. In G1B, type I PVA was absent and replaced by hypertrophic type II cells; b) Bruch's membrane (BM) was thinner in G1B than in G1A; c) the retinal pigment epithelium (RPE) cytoplasm contained fewer lipids in G1B than in G1A; d) in G1A and G1B choriocapillaris and retinal vessel showed alterations with respect to G0; e) cell death and axonal degeneration in the retina were similar in G1A and G1B. The substitution of a hyperlipemic diet by a standard one normalizes blood-lipid levels. However, the persistence of damage at retinal vessels and BM-RPE could trigger chronic ischemia.

Cardiorespiratory fitness and cardiometabolic risk factors in schoolchildren from Colombia: The FUPRECOL Study

The objectives of this study are to investigate the association between cardiorespiratory fitness and cardiovascular risk factors in schoolchildren and to evaluate the degree of association between overall and abdominal adiposity and cardiorespiratory fitness. A total of 1,875 children and adolescents attending public schools in Bogota, Colombia (56.2% girls; age range of 9–17.9 years). A cardiovascular risk score (Z-score) was calculated and participants were divided into tertiles according to low and high levels of overall (sum of the skinfold thicknesses) and abdominal adiposity. Schoolchildren with a high level of overall adiposity demonstrated significant differences in seven of the 10 variables analyzed (i.e. systolic and diastolic blood pressure, triglycerides, triglycerides/HDL-c ratio, total cholesterol, glucose and cardiovascular risk score). Schoolchildren with high levels of both overall and abdominal adiposity and low cardiorespiratory fitness had the least favorable cardiovascular risk factors score. These findings may be relevant to health promotion in Colombian youth.