39 research outputs found

    Clinical implications of a possible role of vitamin D in multiple sclerosis

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    Hypovitaminosis D is currently one of the most studied environmental risk factors for multiple sclerosis (MS) and is potentially the most promising in terms of new clinical implications. These practical consequences, which could be applied to MS patients without further delay, constitute the main purpose of this review. Vitamin D is involved in a number of important general actions, which were not even suspected until quite recently. In particular, this vitamin could play an immunomodulatory role in the central nervous system. Many and varied arguments support a significant role for vitamin D in MS. In animal studies, vitamin D prevents and improves experimental autoimmune encephalomyelitis. Epidemiologically, latitude, past exposure to sun and the serum level of vitamin D influence the risk of MS, with, furthermore, significant links existing between these different factors. Clinically, most MS patients have low serum levels of vitamin D and are in a state of insufficiency or even deficiency compared to the international norm, which has been established on a metabolic basis. Large therapeutic trials using vitamin D are still lacking but the first results of phase I/II studies are promising. In the meantime, while awaiting the results of future therapeutic trials, it can no longer be ignored that many MS patients have a lack of vitamin D, which could be detected by a serum titration and corrected using an appropriate vitamin D supplementation in order to restore their serum level to within the normal range. From a purely medical point of view, vitamin D supplementation appears in this light to be unavoidable in order to improve the general state of these patients. Furthermore, it cannot currently be ruled out that this supplementation could also be neurologically beneficial

    Biochar: pyrogenic carbon for agricultural use: a critical review.

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    O biocarvão (biomassa carbonizada para uso agrícola) tem sido usado como condicionador do solo em todo o mundo, e essa tecnologia é de especial interesse para o Brasil, uma vez que tanto a ?inspiração?, que veio das Terras Pretas de Índios da Amazônia, como o fato de o Brasil ser o maior produtor mundial de carvão vegetal, com a geração de importante quantidade de resíduos na forma de finos de carvão e diversas biomassas residuais, principalmente da agroindústria, como bagaço de cana, resíduos das indústrias de madeira, papel e celulose, biocombustíveis, lodo de esgoto etc. Na última década, diversos estudos com biocarvão têm sido realizados e atualmente uma vasta literatura e excelentes revisões estão disponíveis. Objetivou-se aqui não fazer uma revisão bibliográfica exaustiva, mas sim uma revisão crítica para apontar alguns destaques na pesquisa sobre biochar. Para isso, foram selecionados alguns temaschave considerados críticos e relevantes e fez-se um ?condensado? da literatura pertinente, mais para orientar as pesquisas e tendências do que um mero olhar para o passad

    The composition and stability of the vaginal microbiota of normal pregnant women is different from that of non-pregnant women

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    Humic acid composition and soil fertility of soils near an ancient charcoal kiln: are they similar to Terra Preta de Índios soils?

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    6 páginas.-- 5 figuras.-- 1 tabla.-- 31 referenciasPurpose: Charcoal production during the nineteenth century transformed landscapes in the Brazilian Atlantic Forests in Rio de Janeiro city. These paleo-territories were studied to improve our understanding of how this activity altered soil properties. By comparing their humic acids (HA) with those extracted from a Terra Preta de Índios (TPI) site, we showed that the aging of charcoal in soils alone is sufficient to generate recalcitrant organic material with high cation exchange capacity (CEC). Materials and methods: The soils were sampled: at the center of the area affected by the ancient charcoal kiln (center of the kiln—CK), at the dump site (D—local deposition of charcoal residues not used for marketing, downstream of the ancient charcoal kiln), and from the surrounding soil, upstream of the kiln, as a control (natural soil—NS). Elemental analysis and fertility characterization of the soil samples were performed. Solid-state 13C nuclear magnetic resonance (NMR) spectra were obtained from their humic acids (HA). These spectra were compared against HA data on TPI. Results and discussion: As shown by solid-state 13C NMR spectroscopy, the soil organic matter (SOM) fraction which is high in charged functional groups (the so-called humic acids—HA) was extracted from areas rich in ancient charcoal and dominated by recalcitrant carboxylated aromatic structures (aged charcoal). This peculiar SOM explains the observed high cation exchange capacity (CEC). It yields a fertile soil with a high resistance against degradation by potential intensive use. Comparable results are described in the literature for SOM of TPI. Conclusions: The high structural similarity between the HA from the soils under the paleo-charcoal kilns and from TPI supports the hypothesis that just the natural weathering and biochemical reworking of charcoal in soils, together with ash input, is sufficient to generate fertile and resilient soils with peculiar SOM and properties commonly associated with the high fertility and C sequestration potential of TPIThis study was financially supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq)Peer reviewe
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