A Selective Fluorescent Probe for the Determination and Imaging of Fluoride in Living Cells

Abstract Fluoride anions are indispensable trace elements required for sustaining life. To investigate the homeostasis and action of fluoride in the body, a new highly sensitive and selective fluorescence detection method was designed for fluoride in aqueous solutions. A fluorescent probe for fluoride (FP-F) was synthesized for imaging F- in living cells. The design strategy for the probe was based on the specific reaction between fluoride and silica to mediate deprotection of this probe to fluorescein. Upon treatment with F-, FP-F, a closed and weakly fluorescent lactone, was transformed into an open and strongly fluorescent product. Under the optimum conditions, the detection limit for fluoride was 0.526 nM. FP-F could detect micromolar changes in F- concentrations in living cells by confocal microscopy.

Germinação de Phaseolus aureus contaminados com diferentes fontes de cromo (VI) / Germination of Phaseolus aureus contaminated with different sources of chromium (VI)

O excesso de Cr nas plantas pode provocar inibição no crescimento das plantas, clorose nas folhas, desequilíbrio nutricional e alteração na germinação das sementes, sendo também altamente tóxico para humanos. Objetivou-se avaliar a germinação de sementes de feijão submetidas a diferentes fontes de Cr, em câmara germinadora durante 9 dias. As fontes de Cr utilizadas: cromato de potássio e dicromato de potássio, em 128 subamostras em soluções de concentrações crescentes de Cr (0, 5,10, 20, 45, 90, 200 e 400 mg L-1). Realizou contagem de sementes normais, anormais e mortas. Conclui-se que sementes de feijão submetidas ao dicromato de potássio germinam 47,5% em média, sem efeitos prejudiciais ao seu desenvolvimento, com apenas 0,87% de sementes anormais e 1,6% em média de sementes mortas, ambas com tolerância de até 400 mg L-1.

Effect of zinc-free diet from weaning through puberty on the structure of the testis in albino rats, with a special focus on the Leydig cells

Zinc is an essential trace element. Many physiological processes would be impaired if zinc is not supplied in sufficient quantities in the diet. The aim of the work was to evaluate the effect of a zinc-free diet from weaning through puberty on the testicular structure of rats, with a special focus on the Leydig cells. Twenty weaned rats were divided into three groups. Group I [the control group] was fed a balanced diet. Group II [the zinc-free group] was fed a zinc-free diet for 3 months. Group III [the recovery group] was fed a zinc-free diet for 3 months, followed by a balanced diet for 1 month. At the end of the experiment, rats were weighed and blood samples were collected to measure the level of serum testosterone hormone. The testes were removed, weighed, and processed for light and transmission electron microscopic study. The zinc-free group showed a significant decrease in the mean body weight, testis weight, and serum testosterone level compared with the control group. The light and electron microscopic examination showed loss of most of the spermatogenic cells accompanied by variable degrees of degeneration in the form of karryorhexis and haphazard chromatin content. In the interstitial tissue, there was accumulation of exudate. Many Leydig cells showed dilated smooth endoplasmic reticulum and mitochondria. Others cells showed accumulation of glycogen. Most of these changes were reversed after receiving the balanced diet in the recovery group. A zinc-free diet altered the structure of both the seminiferous tubules and the Leydig cells. Most of these alterations were reversed by zinc replenishment. Zinc is considered an essential element for maintaining testicular structure and spermatogenesis process

Introduction of routine zinc therapy for children with diarrhoea: evaluation of safety.

On 8 May 2004, the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) recommended routine administration of zinc in the management of children, aged less than five years, with acute diarrhoea. In making the recommendation, WHO and UNICEF also suggested careful monitoring for adverse events associated with routine administration of zinc, particularly unusual or excess vomiting. The study assessed, in a phase IV trial, i.e. post-marketing surveillance of zinc, the occurrence of adverse events during the first hour after the administration of the first dose of zinc in children with acute or persistent diarrhoea. The study was conducted at the Dhaka Hospital of ICDDR,B and at an outpatient clinic operated by a local health NGO-Progoti Samaj Kallyan Protisthan (PSKP), Dhaka, Bangladesh. Eligible children, aged 3-59 months, were treated with 20 mg of zinc sulphate provided in a dispersible tablet formulation. The children were observed for 60 minutes following the initial treatment with zinc for adverse events, with particular attention given to vomiting or regurgitation. During the one-year observation period, 42,440 children (male 57% and female 43%) received zinc, and 20,246 (47.8%) of them were observed. Regurgitation and/or vomiting occurred in 4,392 (21.8%) of the children; 90.8% of these children had vomiting only once, 8.7% twice, and 0.5% more than twice. No children revisited the hospital for recurrent vomiting following their discharge. A significant proportion of infants and children may experience vomiting or regurgitation, usually once, following the administration of the first dose of zinc. This is a transient phenomenon that did not impact on continuation of treatment with zinc.

Initiation of zinc treatment for acute childhood diarrhoea and risk for vomiting or regurgitation: a randomized, double-blind, placebo-controlled trial.

The childhood diarrhoea-management guidelines of the World Health Organization/United Nations Children's Fund (WHO/UNICEF) now include zinc treatment, 20 mg per day for 10 days. To determine if a dispersible zinc sulphate tablet formulation is associated with increased risk of vomiting or regurgitation following the initial, first treatment dose, a double-blind, placebo-controlled randomized clinical trial was carried out in the Dhaka hospital of ICDDR,B: Centre for Health and Population Research (n=800) and in an adjacent NGO outpatient clinic (n=800). Children were randomized to one of three groups: no treatment, placebo, or zinc sulphate tablet (20 mg). They were then observed for 60 minutes, and all vomiting or regurgitation episodes were recorded. When compared with placebo, zinc treatment resulted in an attributable risk increase of 14% for vomiting and 5.2% for regurgitation. The median time to vomiting among those receiving zinc was 9.6 minutes and was limited to one episode in 91.2% of the cases. Overall, the proportion of 60-minute post-treatment vomiting attributable to zinc, placebo, and the illness episode was estimated to be 40%, 26%, and 34% respectively. The dispersible zinc sulphate tablet formulation at a dose of 20 mg is associated with increased risks of vomiting and regurgitation. Both are transient side-effects.

Interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, Amazonas, Brazil: effect of supplementation with vitamin A, zinc and zinc and vitamin A / Interacao de zinco e vitamina A em ratos recebendo uma dieta Regional de Manaus, Amazonas, Brazil: efeito da supplementacao com vitamina A, zinco e zinco e vitamina A

The interaction of zinc and vitamin A in rats receiving a regional diet pf Manaus, supplemented with vitamin A, zinc and zinc and vitamin A was studied. The regional diet was elaborated according to data of Shrimpton and Giugliano (6), for families receoving less than two minimun salaries. The biological test to study the interaction based on the depletion of zinc and vitamin A in rats in the period of lactation, and a period of repletion where supplements of zinc (0.82 mg por ciento) and vitamin A (94,2 µg por ciento) were given, either separately or together, according to the recommendations of the Committee on Laboratory Animal Diets (7). From the results, it was concluded that was an interaction of these nutrients in terms of mobilization of hepatic vitamin A. Although the regional diet of Manaus did not meet the zinc RDA, the amount present was enough to utilize the available vitamin A. Although the amount of zinc present in the diet, as determined by parameters of biovailability, such as growth, concentration in organs and zinc-dependent enzymes, was adequately used by the animals, probably due to promoting factors in the diet. The Manaus regional diet needs to be supplemented with vitamin A in order to maintain the hepatic reserves, and with zinc, to maintain the normal levels of vitamin A in plasma

Efeitos da diclorfenamida sobre a concentraçäo de zinco no humor aquoso e no sangue de cäes / Dicholorphenamide effects on zinc concentration in dog's aqueous humor and blood

Os óligo-elementos, embora presentes em quantidades diminutas no organismo, säo de extrema importância para a vida. O zinco é o segundo óligo-elemento mais abundante do corpo humano, sendo essencial para o desenvolvimento normal dos seres vivos. É componente necessário e integrante da anidrase carbônica, que constitui uma metaloenzima que se encontra em várias formas de isoenzima no corp. Nos processos ciliares de olhos humanos, ela é quase inteiramente pura; mediante a sua inibiçäo, consegue-se, provadamente pela filtraçäo da parede capilar, reduzir a produçäo do humor aquosos e, consequentemente, da pressäo ocular. Entre os inibidores da anidrase carbônica está a diclorfenamida, sendo uma sulfonamida comercializada em nosso meio, somente para uso oral. Este trabalho visou testar o efeito da diclorfenamida sobre o zinco do humor aquoso e do sangue, supondo-se uma interferência do zinco no controle da pressäo ocular; para isto foram estudados, em dezenove cäes, trinta e oito olhos, sendo que para cada cäo, um olho foi controle do outro

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

Oligoelementos en clínica-II-plomo / Trace elements in clinic-II-lead

Se presenta una actualización de los efectos del plomo sobre la salud. Se describen los síntomas de la intoxicación aguda y crónica en adultos y niños alertando sobre la importancia de efectos mal llamados "subclínicos" que afectan especialmente el SNC. Se explican los efectos neurotóxicos del plomo y la importancia de considerar la carga corporal real medible por análisis de cabellos dándose los valores máximos tolerables. Se presentan las propiedades geno y teratotóxicas del metal que tienen importancia en neonatología. Se menciona su importancia en toxicología conductual destacando los efectos sobre el C.I. de niños desde dosis bajas y el posible desarrollo de conducta violenta, destacando la muy posible falta de umbral en estos efectos. Se dan datos sobre la ingesta y excreción del metal enfatizando su ingreso por el agua y en las ciudades por el aire en zonas de alto tránsito automotor. Se da una suscinta idea sobre modos de prevención y tratamiento y la importancia de la eliminación del plomo en las naftas. Se informa sobre las investigaciones a efectuar para detectar la contaminación y posibles sinergias, y los nuevos intervalos de referencia a considerar, hasta 300 µg/l en sangre de adultos hasta 200 µg/l en niños.