Disponibilidad potencial in vitro de hierro y zinc en una dieta infantil con pan fortificado con distintas fuentes de hierro o con agregado de promotores de la absorción / Iron and zinc in vitro potential availability in an infant diet with fortified bread with different iron sources or with the adition of different iron absorption promoters

Los alimentos complementarios más utilizados son las dietas caseras. En el presente trabajo se evaluó la disponibilidad de hierro y zinc en una dieta infantil de consumo habitual conteniendo pan fortificado con diferentes fuentes de hierro: sulfato ferroso, bisglicinato ferroso, NaFeEDTA. También se utilizó pan sin fortificar con agregado de ácido ascórbico, citrato de sodio o Na2EDTA como promotores de la absorción, combinada con diversas bebidas. La dieta (papa, zapallo, sémola, pan y manzana) se combinó con agua, leche, té, bebida cola y bebida artificial a base de naranja. La dializabilidad (D) mineral, como indicador de la disponibilidad potencial fue determinada utilizando un método in vitro. El análisis estadístico se realizó utilizando ANOVA, con test de Tukey a posteriori. No hubo diferencias significativas en la DFe entre las dietas del pan fortificado con sulfato o bisglicinato; con el NaFeEDTA aumentó significativamente (p<0,05). El aumento de la DFe fue mayor en las dietas que tenían panes con promotores que en las que tenían panes fortificados. La bebida a base de naranja aumentó la DFe, mientras que el té y la leche la disminuyeron significativamente (p<0,05). La DZn aumentó en forma significativa cuando el pan estaba fortificado con sulfato o NaFeEDTA, pero no cuando se fortificó con bisglicinato. El agregado de té o leche disminuyó la DZn mientras que la bebida a base de naranja la aumentó significativamente (p<0,05). En relación a los promotores, las mayores DFe y DZn se observaron en las dietas con el pan sin fortificar, con agregado de Na2EDTA.

Home-made diets are the most frequently used complementary foods. In the present work we evaluated iron and zinc availability in a usually consumed infant diet containing either iron-fortified bread with different iron sources: ferrous sulfate, ferrous bisglycinate, NaFeEDTA. We also used non-fortified bread with absorption promoters: ascorbic acid, sodium citrate, Na2EDTA, combined with different beverages. The diet (potato, pumpkin, grits, bread, and apple) was combined with water, milk, tea, a soft drink and an orange-based artificial drink. Mineral dialyzability (D) as an indicator of potential availability was determined using an in vitro method. Statistical analysis was performed by ANOVA, and a posteriori Tukey test. There were no significant differences in FeD between diets with ferrous sulfate or ferrous bisglycinate fortified bread; in NaFeEDTA fortified bread it increased significantly (p<0.05). Iron D increase was greater in diets with bread containing absorption promoters than in those with fortified bread. The orange-based artificial drink increased FeD, while tea and milk decreased it significantly (p<0.05). Zinc D increased significantly when the bread was fortified either with ferrous sulfate or NaFeEDTA, but remained unchanged in diets with ferrous bisglycinate fortified bread. The addition of tea or milk decreased ZnD while the orange-based artificial drink increased it significantly (p<0.05). Regarding absorption promoters, the greater values both in FeD and ZnD were observed in diets with iron nonfortified bread containing Na2EDTA.

Dializabilidad de hierro y zinc en cereales para desayunos comerciales fortificados con hierro elemental, sulfato ferroso o edta férrico sódico / Iron and zinc dialysability in commercial breakfast cereals fortified with elemental iron, ferrous sulphate or ferric sodium edta

Iron (Fe) and Zinc (Zn) dialyzability was compared in 7 commercial ready-to-eat breakfast cereals (BC). Four of them were fortified with elemental Fe and ZnO. Fe and Zn dialyzability of 3 different types of BC fortified with ZnO and FeNa2EDTA or FeSO4 was also performed in our laboratory. An in vitro methodology that measures the percentage of mineral dialyzability (D percent) with controlled pH was used. The DFe percent values obtained for the commercially fortified BC ranged between 0.4 to 15.0 percent without milk and between 1.0 to 5.6 percent when milk was added to the cereals. In the case of Zn, the values ranged from 3.3 to 16.1 without milk and between 3.3 and 30.8 when milk was added. Almost every BC that was experimentally fortified in our laboratory presented a higher DFe percent (19.5 to 28.6 percent) and DZn percent (12.4 to 29.2) when fortified with FeNa2EDTA (with or without milk). The results obtained suggest that FeNa2EDTA is a viable alternative for the fortification of BC.

Se comparó la dializabilidad de Fe y Zn en 7 cereales para desayuno comercialmente fortificados o no, con Fe elemental y ZnO y se comparó la dializabilidad de Fe y Zn en tres tipos diferentes de cereales experimentalmente fortificados con ZnO y FeNa2EDTA o FeSO4 en el laboratorio. Se utilizó una metodología in vitro que mide el porcentaje de dializabilidad (D por ciento) del mineral en condiciones controladas de pH. Los cereales comercialmente fortificados presentaron valores de DFe por ciento entre 0,4 y 15,0 y entre 1,0 y 5,6; sin y con leche. Para DZn por ciento los valores fueron entre 3,3 y 16,1 y entre 3,3 y 30,8, sin y con leche. Casi todos los cereales fortificados en el laboratorio presentaron mayor DFe por ciento (entre 19,5 y 28,6) y DZn por ciento (entre 12,4 y 29,2) cuando fueron fortificados con FeNa2EDTA (con y sin leche). Los resultados obtenidos muestran al FeNa2EDTA como una alternativa viable para la fortificación de cereales para desayuno.

Accumulation, tolerance and impact of aluminium, copper and zinc on growth and nitrate reductase activity of Ceratophyllum demersum (Hornwort).

Ceratophyllum demersum (homwort) was subjected to toxic concentrations of Al (3 and 9 mg l(-1)), Zn (3 and 9 mg l(-1)) and Cu (2.5 and 7 mg l(-1)) in culture solutions for 15 days. The higher dose of Al enhanced the chlorophyll content significantly (p<0.05) in the first 6 days of treatment while other treatments caused marked reductions. Nitrate reductase activity (NRA) was significantly reduced (p<0.05) byAl, Cu and Zn toxicity and ceased completely in plants treated with Cu by the 6th day of treatment. Dry biomass and relative growth rate were reduced significantly (p<0.05) by metal treatment. Tolerance index of the plant was low for Cu (21.62 and 13.43% at low and high doses, respectively) and moderate for Zn (63.74 and 54.85%) and Al (72.83 and 68.79%). Accumulation ofAl, Zn and Cu was threefold at higher doses compared with the lower doses but the bioconcentration factors (BCF) were very low indicating that this plant is not a hyper accumulator of these metals.

Influence of joint application of heavy metals on level of each metal accumulated in the periwinkle Tympanotonus fuscatus (Gastropoda: Potamididae)

Most laboratory assessments of toxicity and bioaccumulation of heavy metals have been concentrated on the accumulation of these metal ions when exposed singly to the test organisms. However, under the natural environmental settings, the metals are never present in isolation and may interact with each other, therefore justifying the need to study the influence of joint application of metals on accumulated levels in exposed animals. In this study, exposure of the periwinkle Tympanotonus fuscatus to sublethal concentrations (equivalent to 0.1 and 0.01 of 96 h LC50) of heavy metals revealed that they were bioaccumulative varying amounts, depending on the type of metal, exposure period and concentration in the test media. While Zn and Pb ion accumulation increased steadily with exposure time, the amounts of Cu accumulated fluctuated regularly over the 30-day experimental period. The levels of Zn, Cu and Cd bioaccumulated over the 30-day experimental period were reduced by over 2-6 folds (with bioaccumulation ratio values ranging from 0.15 to 0.81) when compared to concentrations of the respective metals accumulated during single bioaccumulation studies. However, Pb concentrations accumulated during the joint action studies increased nearly 2-fold (bioaccumulation ratio range 1.36 to 2.0-fold).

La mayoría de los análisis de laboratorio sobre toxicidad y bioacumulación de metales pesados se han concentrado en la acumulación individual de los iones metálicos en los organismos de prueba expuestos a ellos. Sin embargo, bajo condiciones naturales del ambiente, los metales nunca se presentan en forma aislada y deben interactuar unos con otros, justificando así la necesidad de estudiar el efecto de la aplicación conjunta de metales en animales de prueba. En este estudio la exposición de Tympanotonus fuscatus a concentraciones subletales (0.1-0.01 de 96 h LC50) de metales pesados reveló que la bioacumulación varía según el tipo de metal, el período de exposición y la concentración en el medio de prueba. Mientras los iones de Zn y Pb incrementaron gradualmente su acumulación al pasar el tiempo, las cantidades de Cu fluctuaron regularmente durante los 30 días del experimento. Los niveles de Zn, Cu y Cd bioacumulados durante los 30 días del experimento son de dos a seis veces menores (con un rango de bioacumulación de 0.15-0.81) que los que se obtienen por la exposición a los metales en forma individual. Por el contrario, la acumulación de Pb aumentó al doble (rango de bioacumulación 1.36-2.0).

Piroxicam-zinco: cinética em sangue e linfa e efeito na mucosa gástrica / Zinc-piroxicam: kinetic in blood and lymph and effect on the gastric mucosa

Vários mecanismos foram propostos para reduzir a toxicidade gástrica dos fármacos antiinflamatórios. A complexação com zinco foi proposta considerando-se o fato de que o zinco possui ação protetora sobre a mucosa gástrica. O complexo piroxicam-zinco apresenta atividade antiinflamatória e analgésica semelhantes às do fármaco livre. No entanto, a modificação de propriedades físico-químicas acarretou alteração do perfil cinético do fármaco. A fim de investigar as diferenças farmacocinéticas, o complexo piroxicam-zinco foi estudado quanto à farmacocinética em sangue e linfa de ratos. Estudaram-se também os efeitos do complexo na mucosa gástrica em comparação com o piroxicam livre em modelos de úlcera induzida por ácido acetilsalicílico e por etanol...

Cinc: conceptos actuales sobre un micronutriente esencial / Cinc: conceptos on an essential micronutrient

Se ha postulado que el aporte de hierro a las células usuarias se halla bajo un control dependiente del tamaño de la fracción intracelular libre del metal, cuyos cambios se reflejarían en mensajes a la expresión de los receptores séricos o de membrana para ajustar la oferta a la demanda. La posibilidad de que los receptores de membrana pudieran estar afectados por la malnutrición calórico-proteica se exploró en estudios a través de los cambios de la capacidad de los reticulocitos circulantes de ratón normal para incorporar hierro in vitor, observando el diferente comportamiento ocasionado por la incubación de las células con suero humano de dadores normales y de pacientes de anemia nutricional. Los resultados muestran una significativa caída de dicha capacidad cuando se utilizó suero de pacientes afectados de anemia nutricional. Se discute el probable mecanismo responsable de dicha diferencia.

Protective effect of zinc gluconate on chemically induced gastric ulcer.

This study was undertaken in rats to ascertain the role of zinc as an antiulcerogenic agent employing its more bioavailable gluconate derivative. Pretreatment with zinc gluconate 10 mg/kg body wt orally for three consecutive days, protected against alcohol induced gastric epithelial damage and also significantly prevented non-steroidal anti-inflammatory drugs (NSAID) induced gastric ulcer in rats. The enhanced levels of mucus, and hexosamine and decreased acid output in the gastric secretion of zinc treated rats, increased the gastric mucosal barrier. Studies on the mechanism of action suggested the involvement of -SH groups in producing gastric antisecretory effect. Thus, zinc gluconate at > > 100 microM concentrations inhibited H(+)-ion transport which could be reversed by incorporating beta-mercaptoethanol in the secretory solution (luminal side). On the other hand, beta-mercaptoethanol added from the nutrient side showed no effect on the inhibition of H(+)-transport indicting that the implication of -SH groups may not be the sole factor. Zinc appeared to play a vital and multifaceted protective role in chemically induced gastric ulcer disorders.

Efeito da suplementaçäo com ferro na biodisponibilidade de zinco em uma dieta regional do nordeste do Brasil / Effects of supplementation with iron on the bioavailability of zinc in the regional diet of northeastern Brazil

Foram investigados os efeitos da suplementaçào com ferro na biodisponibilidade de zinco de uma dieta regional do Nordeste (DRNE), em ratos albinos Wistar, consumindo raçöes à base da referida dieta (DRNE) e raçöes controle. As raçöes DRNE continham 16 mg de Zn/Kg e níveis de 35 mg, 70 mg e 140 mg Fe/Kg. As raçöes controle foram elaboradas segundo o "Committee on Laboratory Animal Diets", contendo níveis de proteína, ferro e zinco ajustados aos das raçöes experimentais DRNE. Os parâmetros utilizados para medir a biodisponibilidade do zinco foram: índice de absorçäo aparente do Zn e nível total de Zn nos fêmures. Os resultados obtidos demonstraram que a suplementaçäo com ferro diminuiu a biodisponibilidade do Zn, e os efeitos dessa interferência foram influenciados pela qualidade da dieta e pelas proporçöes Fe:Zn. Tal fato deve ser considerado nas práticas que envolvem fortificaçäo de alimentos e/ou suplementos medicamentosos, comuns nas populaçöes com carências nutricionais

Levaduras aisladas de mostos de uva en la zona de Oltrepo Pavese, Italia, y su sensibilidad in vitro frente a compuestos de cobre y zinc / Yeast isolated from musts of grapes in Oltrepó Pavese, Italy, and their in vitro sensibility to zinc and copper compounds

Se investigó durante el periodo 1989-90 en la región de Oltrepó Pavese (Italia), la micota de los mostos provenientes de uvas negras y blancas. De un total de 28 especies levaduriformes aisladas, incluidas en 10 géneros, Saccharomyces, fué el género dominante con las especies S.italicus y S.cerevisiae. Tambien se detectaron frecuentemente levaduras anascosporógenas, tales como Candida valida, Torulopsis (C) holmii y Kloeckera apiculata. Se efectuaron estudios de sensibiliadad in vitro frente a compuestos de CuSO4, ya sea en cepas de S. cerevisiae aisladas de los mostos, como de Alternaria, Botrytis, Cladosporium y Sporobolomyces, aisladas del filoplano de la uva. Las concentraciones de CuSO4 a 0.007M y a 0,062M, fueron fúngicidas para S.cerevisiae y Sporobolomyces roseus respectivamente

Biodisponibilidade de zinco em dieta regional de Säo Paulo / Zinc bioavailability in the regional diet of Säo Paulo

A biodisponibilidade de zinco em dieta regional de Säo Paulo, da populaçäo com renda menor que 2(dois) salários mínimos, foi estudada em ratos alinos Wistar, recém-desmamados, com peso ao redor de 47.0g. Foram formados três grupos de animais, um experimental, que recebeu raçäo à base da dieta regional de Säo Paulo (DRSP), ad libitum, e os outros dois contrôles, que receberam raçäo à base de caseína suplementada com metionina (CA), "pair feeding" e ad libitum, por um período de 60 dias. As raçöes continham 11% de proteína e 11 mg de zinco/Kg. Para se avaliar a biodisponibilidade de zinco utilizou-se o Indice de absorçäo aparente de zinco e o nível de zinco na carcaça (AU). Observou-se que a biodisponibilidade de zinco da raçäo DRSP é baixa quando comparada com a raçäo contrôle CA. Houve uma correlaçäo positiva significativa entre a quantidade absorvida de zinco e o nível de zinco na carcaça