Effects of zinc supplementation on cognitive function in healthy middle-aged and older adults: the ZENITH study

A randomised double-blind placebo-controlled design was employed to investigate the effects of Zn supplementation on cognitive function in 387 healthy adults aged 55–87 years. Several measures of visual memory, working memory, attention and reaction time were obtained using the Cambridge Automated Neuropsychological Test Battery at baseline and then after 3 and 6 months of 0 (placebo), 15 or 30 mg Zn/d. Younger adults (70 years), and performance improved with practice on some measures. For two out of eight dependent variables, there were significant interactions indicating a beneficial effect (at 3 months only) of both 15 and 30 mg/d on one measure of spatial working memory and a detrimental effect of 15 mg/d on one measure of attention. Further work is required to establish whether these findings generalise to older adults in poorer mental and physical health and with less adequate Zn intake and status than the present sample

The immune system and the impact of zinc during aging

The trace element zinc is essential for the immune system, and zinc deficiency affects multiple aspects of innate and adaptive immunity. There are remarkable parallels in the immunological changes during aging and zinc deficiency, including a reduction in the activity of the thymus and thymic hormones, a shift of the T helper cell balance toward T helper type 2 cells, decreased response to vaccination, and impaired functions of innate immune cells. Many studies confirm a decline of zinc levels with age. Most of these studies do not classify the majority of elderly as zinc deficient, but even marginal zinc deprivation can affect immune function. Consequently, oral zinc supplementation demonstrates the potential to improve immunity and efficiently downregulates chronic inflammatory responses in the elderly. These data indicate that a wide prevalence of marginal zinc deficiency in elderly people may contribute to immunosenescence

Interleukin-6, TNF-alpha and interleukin-1 beta levels in blood and tissue in severely burned rats.

International audiencePrevious studies have demonstrated the early appearance of inflammatory cytokines in the systemic circulation after thermal injury both in humans and animals. The aim of this study was to evaluate the time course of several cytokines, IL-6, TNF-alpha and IL-1beta in serum, lung, liver and brain of severely burned rats during the first week after thermal injury. Cytokine measurements were performed by enzyme-linked immunosorbent assay (ELISA). The comparison between the sham-burned animals and animals with third-degree burns on 20% or 40% of their total body surface area allowed for the study of the inflammatory process relative to the size of the injury. Serum IL-6 levels, which were undetectable in sham-treated animals, peaked during the first hours after injury and were proportionate to the size of the area burned. After a few days, IL-6 increased once more, but only in the most severely burned rats. In lung, liver and brain, low but measurable basal levels of TNF-alpha and IL-1 were detected in sham-burned animals. Strikingly, IL-1beta levels remained significantly elevated in the lung after injury in animals having 20% and 40% burned skin area. Unexpectedly, both TNF-alpha and IL-1beta production decreased gradually in liver and brain after burn injury. Also, the inflammatory response after a burn injury appeared to be biphasic. The first period corresponded to the early release of IL-6 into the circulation, proportional to the severity of the injury. After a few days, a second period was marked by the extension of the inflammatory processes from the injured area to the rest of the body, particularly to lung, which could be considered as at potential risk of involvement in severely burned patients

Elemento para la determinación de nitrato

Número de publicación: 2 259 541 Número de solicitud: 200500199Elemento para la determinación de nitrato en diversos problemas que no exige tratamiento de la muestra o bien que este es mínimo y permite una determinación simple y económica. El elemento se basa en el empleo de receptores sintéticos para nitrato y la señal óptica se consigue mediante el acoplamiento en la membrana sensora hidrófoba de un indicador ácido-base lipotilizado. La medida u observación del cambio de color de rojo a azul dependiendo de la cantidad de nitrato en el problema permite su determinación en un amplio rango de concentraciones con buena precisión y selectividad frente a aniones concomitantes con nitrato. El presente elemento analítico puede ser una alternativa con ventajas en cuanto a rapidez, precisión y costo sobre los métodos analíticos tradicionales y sobre las tiras reactivas comerciales de empleo habitual en análisis de aguas y agrícolas.Universidad de Granad

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet.

International audienceAs an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn-induced oxidative stress, in an animal model. After 8 weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled 1-10 days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters, and antioxidant enzymes were also studied in blood and organs. The zinc-depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients