Vitaminas e minerais com propriedades antioxidantes e risco cardiometabólico: controvérsias e perspectivas

No processo celular de obtenção de energia, são gerados compostos chamados espécies reativas de oxigênio (ERO) que, em excesso, podem causar danos celulares. Estresse oxidativo resulta do desequilíbrio no estado de óxido-redução a favor da oxidação. Dos mecanismos de defesa antioxidante, participam enzimas endógenas e algumas vitaminas e minerais. A vitamina E encontra-se no plasma e na partícula de LDL, protegendo lipídeos da oxidação. Estudos observacionais relataram associação inversa entre ingestão de vitamina E e risco cardiometabólico (RCM). Entretanto, ensaios clínicos não comprovaram a eficácia de sua suplementação nos desfechos cardiometabólicos. A vitamina C participa do sistema de regeneração da vitamina E, mantendo o potencial antioxidante plasmático. Dados sobre os benefícios de sua suplementação na redução do risco cardiometabólico são inconclusivos. A atividade antioxidante dos carotenoides é responsável, em parte, por seu papel protetor contra doenças cardiovasculares e cânceres. A suplementação desse nutriente também não trouxe resultados consistentes no que se refere à redução do RCM. A participação do zinco e do selênio na defesa antioxidante vem sendo estudada mais recentemente, mas a sua suplementação em indivíduos com níveis séricos normais e ingestão adequada na dieta desses minerais não parece ser necessária. De um modo geral, há muita controvérsia sobre o papel desses micronutrientes no RCM. Estudos epidemiológicos sugerem que o consumo de substâncias antioxidantes provenientes da dieta ou dietas ricas em frutas e hortaliças diminui o RCM. Mais estudos são necessários antes de se recomendar o uso de antioxidantes isolados na forma de suplementos para tal finalidade.

Aspectos atuais sobre aminoácidos de cadeia ramificada e exercício físico

Em humanos saudáveis, nove aminoácidos são considerados essenciais, uma vez que não podem ser sintetizados endogenamente e, portanto, devem ser ingeridos por meio da dieta. Dentre os aminoácidos essenciais, se incluem os três aminoácidos de cadeia ramificada, ou seja, leucina, valina e isoleucina. Esses aminoácidos participam da regulação do balanço protéico corporal além de serem fonte de nitrogênio para a síntese de alanina e glutamina. No tocante à regulação da síntese protéica muscular, verifica-se que a leucina age estimulando a fase de iniciação da tradução do RNA-mensageiro em proteína, por mecanismos tanto dependentes quanto independentes de insulina. No que concerne ao exercício físico, supõe-se que esses aminoácidos estejam envolvidos na fadiga central, no balanço protéico muscular, na secreção de insulina, na modulação da imunocompetência, no aumento da performance de indivíduos que se exercitam em ambientes quentes e na diminuição do grau de lesão muscular. Nesse contexto, essa revisão aborda os aspectos atuais do metabolismo e da suplementação de aminoácidos de cadeia ramificada no exercício físico.

Influence of food components on lipid metabolism: scenarios and perspective on the control and prevention of dyslipidemias

Cardiovascular diseases (CVD) are the main causes of death in the Western world. Among the risk factors that are modifiable by diet, for reducing cardiovascular disease risks, the total plasma concentrations of cholesterol, triglycerides, LDL-C, and HDL-C are the most important. Dietary measures can balance these components of the lipid profile thus reducing the risk of cardiovascular diseases. The main food components that affect the lipid profile and can be modified by diet are the saturated and trans fats, unsaturated fats, cholesterol, phytosterols, plant protein, and soluble fiber. A wealth of evidence suggests that saturated and trans fats and cholesterol in the diet raise the total plasma cholesterol and LDL-C. Trans fats also reduce HDL-C, an important lipoprotein for mediating the reverse cholesterol transport. On the other hand, phytosterols, plant proteins, isoflavones, and soluble fiber are protective diet factors against cardiovascular diseases by modulating plasma lipoprotein levels. These food components at certain concentrations are able to reduce the total cholesterol, TG, and LDL-C and raise the plasma levels of HDL-C. Therefore, diet is an important tool for the prevention and control of cardiovascular diseases, and should be taken into account as a whole, i.e., not only the food components that modulate plasma concentrations of lipoproteins, but also the diet content of macro nutrients and micronutrients should be considered.

Determinação espectrofotométrica do bromidrato de fenoterol em preparações farmacêuticas

Um método espectrofotométrico simples foi desenvolvido para a determinação do bromidrato de fenoterol (BF) em comprimidos, gotas e xarope, como princípio ativo único e associado ao ibuprofeno. O método se baseia na reação de acoplamento oxidativo do BF com o 3-metil-2-benzotiazolinona hidrazona (MBTH), na presença de sulfato cérico, como agente oxidante. A mistura de BF, MBTH e sulfato cérico, em meio ácido, produz um composto colorido (vermelho castanho) com máximo de absorção a 475 nm. A curva de calibração foi linear num intervalo de concentração de 3,0 a 12,0 µg/mL, com coeficiente de correlação linear de 0,9998. Os parâmetros experimentais que afetam o desenvolvimento e a estabilidade do produto colorido foram cuidadosamente estudados e otimizados. O método foi aplicado em amostras comerciais e simuladas, obtendo-se coeficientes de variação entre 0,25 % a 0,82 % e médias de recuperação do padrão que variaram de 98 % a 102 %. O método proposto mostrou-se exato, preciso, linear e não é passível de interferência de excipientes, para as formas farmacêuticas comprimidos e gotas. Não houve interferência do ibuprofeno que consta de uma das formulações analisadas, associado ao BF. Quanto ao xarope, houve interferência do veículo sugerindo reações de seus componentes com o MBTH.

Effects of ascorbic acid supplementation in ileum myenteric neurons of streptozotocin-induced diabetic rats

The exacerbation of the oxidative stress and of the polyol pathway which impair damage myenteric plexus are metabolic characteristics of diabetes. The ascorbic acid (AA) is an antioxidant and an aldose reductase inhibitor, which may act as neuroprotector. The effects of AA supplementation on the density and cellular body profile area (CP) of myenteric neurons in STZ-induced diabetes in rats were assessed. Four groups with five animals each were formed: normoglycemic (C); diabetic (D); AA-treated diabetic (DS) and AA-treated normoglycemic (CS). Dosagen of 50mg of AA were given, three times a week, for each animal (group DS and CS). Ninety days later and after euthanasia, the ileum was collected and processed for the NADPH-diaphorase technique. There were no differences (P>0.05) in the neuronal density among the groups. The CP area was lower (P<0.05) in the DS and CS groups, with a higher incidence of neurons with a CP area exceeding 200µm² for groups C and D. The AA had no influence on the neuronal density in the ileum but had a neuroprotective effect, preventing the increase in the CP area and allowing a higher number of neurons with a CP area with less than 200µm².

Effect of an energy-deficient diet on populations of ciliate protozoans in bovine rumen

Ten young rumen-cannulated crossbred steers were randomly divided into two groups: a control group (C; n=4), which was fed a balanced diet for daily weight gain of 900g; and a pronounced energy-deprived group (PED; n=6), receiving 30% less of the required energy for maintenance. After 140 days of these alimentary regimes, rumen fluid and urine samples were collected for biochemical and functional tests, before feeding and at 1, 3, 6, and 9 hours after feeding. The energy-deprivation diet caused a significant reduction in the number of Entodinium, Eodinium, Isotricha, Dasytricha, Eremoplastron, Eudiplodinium, Metadinium, Charonina, Ostracodinium, and Epidinium protozoa. There was no effect of the time of sampling in both groups on the total number of ciliates in rumen fluid. A higher number of protozoan forms in binary division were recorded in the control group, at the 6th and 9th hours after feeding (P<0.019). There was a high positive correlation between the total count of protozoans in rumen fluid and glucose fermentation, ammonia, and urinary allantoin excretion index; and a negative correlation between the total count of protozoa and metilene blue reduction, and a medium correlation between the total count of protozoa and total volatile fatty acids concentration. The determination of the protozoa populations does not imply in the use of complex and hard-to-execute techniques, although it is time consuming and needs practice. This exam particularly helps in clinical expected diagnosis.

Digestible lysine and organic zinc for male broiler from 1 to 11 days of age: performance and body composition

This study evaluated levels of digestible lysine and organic zinc for male Ross strain broilers from 1 to 11 days of age. It was used 1,050 chicks distributed in randomized block design, in 5 × 2 factorial scheme, with seven repetitions of 15 birds per experimental unit. The dietary concentrations of digestible lysine were 0.90; 1.00; 1.10; 1.20; and 1.40% combined with 43 and 253 ppm zinc chelate. The diets contained 2,965 ± 18 kcal/kg of apparent metabolizable energy (AME) and 21.48 ± 0.18% of CP. It was determined chemical composition, protein, lipid, mineral and water depositions on carcass and empty body. There was no interaction among the factors digestible lysine and organic zinc. Effect of zinc concentration increase was observed on greatest deposition of body fat, indicating that there is interference in lipid metabolism of the birds in the studied phase. The most pronounced effects resulted from the dietary inclusion of lysine. There was a linear effect on reconstituted body weight as a response to the increase of dietary lysine, which suggests equal or superior requirement to the greatest studied level. However, the deposition of water and protein on the carcass had a quadratic increase, characterizing higher muscle mass accumulation up to the levels 1.25 and 1.27 of this amino acid in the diet. Considering the studied strain, broiler chickens from the first to the 11th days of age require 1.28 ± 0.01% of digestible lysine, according to the deposition of muscle mass.

Flow cytometry as a tool in the evaluation of blood leukocyte function in Chelonia mydas (Linnaeus, 1758) (Testudines, Cheloniidae)

Chelonia mydas is a sea turtle that feeds and nests on the Brazilian coast and a disease called fibropapillomatosis is a threat to this species. Because of this, it is extremely necessary to determine a methodology that would enable the analysis of blood leukocyte function in these sea turtles. In order to achieve this aim, blood samples were collected from C. mydas with or without fibropapillomas captured on the São Paulo north coast. Blood samples were placed in tubes containing sodium heparin and were transported under refrigeration to the laboratory in sterile RPMI 1640 cell culture medium. Leukocytes were separated by density gradient using Ficoll-PaqueTM Plus, Amershan Biociences®. The following stimuli were applied in the assessment of leukocyte function: Phorbol Miristate-Acetate (PMA) for oxidative burst activity evaluation and Zymosan A (Saccharomyces cerevisiae) Bio Particles®, Alexa Fluor® 594 conjugate for phagocytosis evaluation. Three cell populations were identified: heterophils, monocytes and lymphocytes. Monocytes were the cells responsible for phagocytosis and oxidative burst.

Influência da proteína de soja e dos exercícios com pesos sobre o gasto energético de repouso de mulheres na pós-menopausa

OBJETIVO: Analisar a influência da ingestão alimentar de proteína da soja e dos exercícios com pesos sobre o gasto energético de repouso (GER) de mulheres na pós-menopausa. MÉTODOS: Ensaio clínico, 16 semanas, envolvendo 60 mulheres, 59 (7) anos, distribuídas em quatro grupos: G1 (proteína da soja e exercício), G2 (placebo e exercício), G3 (proteína da soja e sem exercício) e G4 (placebo e sem exercício). A proteína da soja e o placebo (maltodextrina) foram distribuídos, aleatoriamente, sob a forma de pó, na porção de 25 gramas/dia. Foram 10 exercícios com pesos, realizados em três sessões semanais, com 3 séries de 8-12 repetições cada, carga de 60 por cento-80 por cento de uma repetição máxima (RM). O GER foi calculado a partir do O2 e CO2, obtidos por calorimetria indireta (Quinton-QMC®), durante 30 minutos, sob temperatura e umidade controladas. Na análise estatística foi utilizada ANOVA, teste T de Student e regressão múltipla, por meio do software Stata 9.2, α<0,05. RESULTADOS: As mulheres apresentaram homogeneidade em todas as variáveis do estudo. Houve aumento, significante, do GER (p<0,05) no G1 (158 kcal/dia) e G2 (110 kcal/dia), correspondente a 17 por cento e 9 por cento, respectivamente, enquanto, o G4, diminuição em 4 por cento (p<0,05). CONCLUSÃO: Exercícios com pesos são determinantes para o aumento do gasto energético de repouso, de mulheres na pós-menopausa, podendo ser potencializado pela ingestão de proteína da soja

Surface dental enamel lead levels and antisocial behavior in Brazilian adolescents

Lead poisoning has been reportedly linked to a high risk of learning disabilities, aggression and criminal offenses. To study the association between lead exposure and antisocial/delinquent behavior, a cross-sectional study was conducted with 173 Brazilian youths aged 14\201318 and their parents (n = 93), living in impoverished neighborhoods of Bauru-SP, with high criminality indices. Self-Reported Delinquency (SRD) and Child Behavior Checklist (CBCL) questionnaires were used to evaluate delinquent/antisocial behavior. Body lead burdens were evaluated in surface dental enamel acid microbiopsies. The dental enamel lead levels (DELL) were quantified by graphite furnace atomic absorption spectrometry (GFAAS) and phosphorus content was measured using inductively coupled plasma optical emission spectrometry (ICP-OES). Logistic regression was used to identify associations between DELL and each scale defined by CBCL and SRD scores. Odd ratios adjusted for familial and social covariates, considering a group of youths exposed to high lead levels (\2265 75 percentile), indicated that high DELL is associated with increased risk of exceeding the clinical score for somatic complaints, social problems, rule-breaking behavior and externalizing problems (CI 95 per cent). High DELL was not found to be associated with elevated SRD scores. In conclusion, our data support the hypothesis that high-level lead exposure can trigger antisocial behavior, which calls for public policies to prevent lead poisoning

A hepcidina como parâmetro bioquímico na avaliação da anemia por deficiência de ferro

A anemia por deficiência de ferro caracteriza-se como o mais prevalente problema nutricional em todo o mundo. Nesta revisão reuniu-se informações a respeito do metabolismo da hepcidina, avaliando-se seu valor como parâmetro bioquímico na anemia por deficiência de ferro. Realizou-se um levantamento bibliográfico nas bases de dados PUBMED e LILACS, período 2006-2010, referentes à hepcidina como um biomarcador para a regulação do metabolismo do ferro. Foram localizados 35 estudos publicados em revistas internacionais e um estudo sobre o assunto em revista nacional. A produção de hepcidina é regulada homeostaticamente pela anemia e hipóxia. Quando a oferta de oxigênio está inadequada ocorre diminuição do nível de hepcidina. Consequentemente, maior quantidade de ferro proveniente da dieta e dos estoques dos macrófagos e hepatócitos se tornam disponíveis. A hepcidina possui a função de se ligar à ferroportina, regulando a liberação do ferro para o plasma. Quando as concentrações de hepcidina estão baixas, as moléculas de ferroportina são expostas na membrana plasmática e liberam o ferro. Quando os níveis de hepcidina aumentam, a hepcidina liga-se às moléculas de ferroportina induzindo sua internalização e degradação, e o ferro liberado diminui progressivamente. Aparentemente o desenvolvimento do diagnóstico e terapia da anemia baseados no bioindicador hepcidina pode oferecer uma abordagem mais efetiva. Estudos epidemiológicos são necessários para comprovar o valor da hepcidina no diagnóstico diferencial das anemias, incluindo protocolos de amostragem para análise, com padronização similar às utilizadas em outras avaliações bioquímicas, e estabelecimento de pontos de corte para a expressão urinária e plasmática desse peptídeo

Effect of n-3 polyunsaturated fatty acids on oxidative stress in rats supplemented with different doses of fish oil

The diet and plasma lipid patterns associated with lipid oxidation susceptibility in rats fed different doses of polyunsaturated fatty acids (n-3 PUFA) from fish oil were evaluated. Wistar rats were assigned into three groups and received diets containing 8% soybean oil (SOY), 4% soybean oil + 4% fish oil (SOY-FISH) and 8% fish oil (FISH) for 21 days. Linoleic, oleic and ?-linolenic acids in SOY diets were substituted by myristic, palmitic, palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in SOY-FISH and FISH diets reducing the n-6/n-3 ratio and increasing the peroxidability index (PI). Increased dietary EPA and DHA were observed in SOY-FISH and FISH plasma at the expense of linoleic and arachidonic acid levels. Saturated fatty acids, which were significantly different between the three diets (P < 0.01), were found at the same concentration in the plasma (P = 0.23). No changes were observed in oxidative stress as measured by the concentration of thiobarbituric acid reactive substances (TBARS) expressed in brain homogenates. However, TBARS concentration in the plasma of the SOY-FISH group was higher than the other two groups (P = 0.02). The major differences between these three groups were the n-3 PUFA content (0.4, 1.8 and 3.2 g/100 g diet) and the saturates/polyunsaturates ratio (0.3, 0.5 and 0.8) for SOY, SOY-FISH, and FISH groups, respectively. Thus, n-3 PUFA intake from fish oil only when followed by a decrease in saturated/polyunsaturated fatty acids ratio increased oxidative susceptibility in rats measured by plasma TBARS concentration

Neurotoxicity and aggressiveness triggered by low-level lead in children: a review

Lead-induced neurotoxicity acquired by low-level long-term exposure has special relevance for children. A plethora of recent reports has demonstrated a direct link between low-level lead exposure and deficits in the neurobehavioral-cognitive performance manifested from childhood through adolescence. In many studies, aggressiveness and delinquency have also been suggested as symptoms of lead poisoning. Several environmental, occupational and domestic sources of contaminant lead and consequent health risks are largely identified and understood, but the occurrences of lead poisoning remain numerous. There is an urgent need for public health policies to prevent lead poisoning so as to reduce individual and societal damages and losses. In this paper we describe unsuspected sources of contaminant lead, discuss the economic losses and urban violence possibly associated with lead contamination and review the molecular basis of lead-induced neurotoxicity, emphasizing its effects on the social behavior, delinquency and IQ of children and adolescents

Echocardiographic study of paediatric patients with mucopolysaccharidosis

Principle Mucopolysaccharidosis is an inborn error of metabolism causing glucosaminoglycans tissue storage. Cardiovascular involvement is variable but contributes significantly towards the morbidity and mortality of the patients. Objective To characterise the echocardiographic abnormalities in children and adolescents with different types of mucopolysaccharidosis. Method Echocardiograms and medical records of 28 patients aged 2–14 years, seen from 2003 to 2005, were revised. At that time, the enzymatic replacement therapy was still not available in our institution.Results Echocardiographic alterations were detected in 26 patients (93 per cent), whereas 16 (57 per cent) had abnormal auscultation, and only 6 (21 per cent) presented with cardiovascular complaint. Mitral valve thickening with dysfunction (regurgitation, stenosis, or double lesion) was diagnosed in 60.8 per cent, left ventricular hypertrophy in 43 per cent and aortic valve thickening with regurgitation in 35.8 per cent of the patients. There was no systolic dysfunction and mild left diastolic dysfunction was shown in 21.5 per cent of the patients. Pulmonary hypertension was present in 36 per cent of the patients, causing the only two deaths recorded. There was a strong association between the accumulation of dermatan sulphate and the presence of mitral valve dysfunction (p = 0.0003), aortic valve dysfunction (p = 0.006), and pulmonary hypertension (p = 0.006). Among individuals with two or more examinations, 82 per cent had a worsening evolution. Conclusions Echocardiographic alterations in children with Mucopolysaccharidosis are frequent and have a progressive character Left valve lesions, ventricular hypertrophy, and pulmonary hypertension were the most common findings and there was an association between the accumulation of dermatan sulphate and cardiovascular involvement. Unlike in adults, pulmonary hypertension was the main cause of death, not left ventricle systolic dysfunction