Selenato e selenito na produção, nutrição mineral e biofortificação com selênio em cultivares de alface

SELENATE and SELENITE on YIELD, MINERAL NUTRITION and BIOFORTIFICATION WITH SELENIUM IN LETTUCE CULTIVARSSelenium is an important antioxidant element associated with physiological processes in plants, microorganisms, animals, and humans. However, its mode of action and essentiality in plants are still disputed. In Brazil, information on Se in agricultural crops is extremely scarce, though there are indications that low levels of Se are being consumed by the population. The objective of this study was to evaluate the effect of selenate and selenite on yield, mineral nutrition and biofortification with Se of lettuce cultivars. The experiment was arranged in a completely randomized factorial design 5 x 3 x 2, with five lettuce cultivars (Maravilha de Verao, Rafaela, Great Lakes, Veneranda, and Vera), three Se concentrations (0, 10 and 20 mu mol L(-1)) and two forms of Se (selenate and selenite), with four replicates. Results indicate that selenate application is more appropriate for biofortification of lettuce cultivars, while the effect of selenite proved to be more toxic. The application of selenate results in increased S shoot concentrations, while selenite reduced P concentrations, and both Se forms decreased micronutrient concentrations. No genotypic variation among lettuce cultivars was observed for Se concentration, and little variation was observed for shoot dry matter yield and S, Mg, Mn, and Fe levels.

Bone repair using mineral trioxide aggregate combined to a material carrier, associated or not with calcium hydroxide in bone defects

Mineral trioxide aggregate (MTA) is a powder aggregate containing mineral oxides with a good biological action and may facilitate the regeneration of the periodontal ligament and formation of bone. Calcium hydroxide demonstrates antibacterial properties, enhances tissue dissolution, and induces bone formation. The objective of this study was to evaluate the MTA in the bone healing process and verify if the calcium hydroxide P.A. can improve and accelerate this process. It was used forty rnale Wistar rats, which were divided into two groups, considering or not the use of calcium hydroxide P.A. solution before treatment. Thus, each one of these groups was divided in four groups with five animals each, according to the treatment and the defect filled by: animal's coagulum, monoolein gel, MTA in aqueous solution, and MTA combined with monoolein gel. After 10 days, the animals were perfused and the right hemimandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups when it was made comparisons using or not calcium hydroxide P.A. (p < 0.0001). There was found statistical difference between the groups that was inserted or not MTA, independently the calcium hydroxide application (p < 0.05). Results showed that the MTA used was able to induce bone regeneration and had its action optimized when combined to calcium hydroxide P.A. (C) 2007 Elsevier Ltd. All rights reserved.

Broiler breeder trace mineral nutrition and feeding practices on embryo progeny development

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Status sócio econômico e deficiência intelectual em escolares

Raven's Progressive Matrices were completed by 536 school children. Wechsler's Intelligence Scale for Children was applied to children who performed badly on Raven's Test (percentile 5 or less). Father's occupation and education, items of property and sums of spending money were assessed in all families. Clinical history and physical examination were recorded for deficient children. Mental deficiency was present in 94 children (17.5%); it was more frequent in those from lower socioeconomic classes (90 deficient children in a total of 427); it was more frequent in the peripheral school (69 deficient children) than in the midtown school (relatively less poor children); no significant difference was found in sex distribution among social classes. 67 children had an intelligence quotient between 50 and 69. Undernourishment was severe marked (18 children), moderate (48 children) or absent (26 children). Most children (67) were insufficiently stimulated by their parents.

Cinética do transporte jejunal de glicose em ratos com deficiência de niacina.

The kinetic of jejunal glucose transport was studied using perfused rat jejunum in vivo. Ninety rats were fed a diet deficient in niacin and 90 a control diet. The jejunal loops of 7 groups of animal were infused each group with one of following solutions of glucose: 5, 10, 20, 40, 80, 160 and 300 mM/l. The Vmax and Km values were determined. The results showed that the vitamin-deficient rats absorbed less glucose independently of the amount infused and these animals had lower Vmax (133.7 microM/15 min/15 cm) and Km (192.1 mM/l) than control groups (294.1 microM/15 min/15 cm and 171.8 mM/l, respectively). In conclusion one can assume that niacin deficiency leads to a decreased glucose absorption in the jejunal loops, when tested as in our experimental model.

Transporte jejunal eletrogênico da glicose em ratos com deficiência de niacina.

The active electrogenic absorption of glucose was studied in 12 niacin deficient rats using a method for measuring changes in transmural potential difference across jejunal mucosa. The glucose was infused in 6 different concentrations (2.5; 5.0; 10.0; 20.0; 50.0 and 100.0 mM/L) at a constant rate of 1.7 ml per minute. The apparent kinetic parameters (Km and Pdmax) of active electrogenic transport were obtained graphically from curves of glucose transfer potentials. The results were compared with that obtained in a control group. The curve of glucose transfer potential in niacin deficient group was significantly lower than that of the control group. The apparent Km of niacin deficient group was greater than in the control group (16.1 x 12.7 mM/L). Furthermore, the Pdmax of the deficient group was lower than that of the control group (12.5 x 19.4 mV). The results showed that in niacin deficiency occurs a decreasing of the active electrogenic glucose absorption. One of the possible interpretation of the differences in the kinetic characteristics of electrogenic glucose transport would be a depleted energy supplement for the active transport in the enterocyte of the niacin deficient rats.

Paraná Basin: Mineral resource potentials in Brazil, Uruguay, and Paraguay

The Paraná Basin is a Western Gondwanan cratonic basin that is better defined as the Paraná depositional site, since it has a diverse history as a basin. Sedimentation started in the Ordovician-Silurian, followed by extensive marine Devonian deposition. A Late Paleozoic/ Triassic facies cycle wedge was clearly built during Pangean time. The Early Cretaceous was characterized by extensive basaltic lava flows immediately before the break-up of Pangea. Following these rifting and drifting processes, the basin's structural framework was totally rebuilt, generating new depositional sites in the Late Cretaceous to Tertiary. Based on more recent data, at least two different basins may be defined during the evolution of what was once considered a unique basin. Nevertheless, even if considered as a single basin, the sedimentary pile of the Paraná Basin has considerable economic potential, until now exploited only rudimentarily, except for its groundwater resources. Aggregates, limestones, clays, industrial sands, gems, dimension stones, hydrocarbons, coal, peat, and uranium are some of the potential mineral resources of this basin. Copyright © 1997 by V. H. Winston & Son, Inc. All rights reserved.

Measuring fluoride concentration in mineral waters in the Araraquara region, Brazil

It has been shown that people of all ages can benefit from the topical and systemic effects of water fluoridation. However, the increase in consumption of bottled water, either to substitute for or supplement consumption of water from public sources, has implications for safe fluoride supplementation. Taking that into consideration, in 1995 we analyzed the fluoride content in 31 commercial brands of mineral water in the region of Araraquara, state of Sao Paulo, Brazil. Fluoride concentration as determined by our analysis was compared to the concentration of fluoride specified on each label. Only 25% of the products studied listed the fluoride concentration on their labels. In addition, among 31 mineral water brands, 26 listed the date when the chemical analysis to determine chemical composition had been performed. Of these, 20 had not been put through the annual chemical analysis determined by Brazilian law. Based on these results, if the mineral waters tested had been the only source of drinking water, fluoride supplementation would have been necessary in 69% of the samples analyzed. In the case of children up to 6 years of age who use products containing fluoride, such as topical gels, mouthwashes or toothpastes, supplementation should be recommended only if commercially bottled water is the only source of water used, not only for drinking but for cooking as well.

Reaction of rat connective tissue to implanted dentin tubes filled with mineral trioxide aggregate or calcium hydroxide

This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted dentin tubes filled with calcium hydroxide or mineral trioxide aggregate. The animals were sacrificed after 7 and 30 days, and the specimens were prepared for morphological study. Some undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for calcium. The results were similar for both studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. It is possible that the mechanism of action of both materials has some similarity. Copyright © 1999 by The American Association of Endodontists.

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo. Copyright © 1999 by The American Association of Endodontists.