Effects of salicylic acid on growth and stomatal movements ofVicia faba L.: Evidence for salicylic acid metabolization

The influence of salicylic acid on the growth and stomatal movements ofVicia faba L. was investigated. Whereas shoot length, fresh weight, and transpiration rates, which are directly correlated with stomatal pore widths, were only affected at salicylic acid concentrations higher than 3.5 mM after long-term treatments, guard cells in epidermal peels exhibited a high sensitivity at concentrations as low as 0.001 mM, resulting in stomatal closing. HPLC analysis of methanolic extracts from roots and leaves revealed the presence of free salicylic acid and a metabolite, whose amount increased with time in plants previously incubated with a medium containing salicylic acid. The possible ability ofVicia faba to detoxify the phenolic acid may be one explanation of the discrepancy between the stomatal reaction in epidermal peels directly treated with the phenolic acid and after application through the transpiration stream. The results indicate that, under natural conditions, salicylic acid will not act as an allelopathic compound whose toxic properties severely affect the growth ofVicia faba.     

Neuromotor outcomes at school age after extremely low birth weight: Early detection of subtle signs.

Objective: Motor impairments are prevalent in children born at extremely low birth weight (ELBW;     

Thermal desorption spectroscopy evaluation of hydrogen-induced damage and deformation-induced defects

ABSTRACT

Thermal desorption spectroscopy (TDS) was performed on ultra-low carbon (ULC) steel with various degrees of hydrogen-induced damage and deformation-induced defects. First, the extent to which hydrogen-induced damage manifests itself in TDS measurements was evaluated. Application of multiple test conditions on cold deformed ULC steel with and without the presence of hydrogen-induced damage showed that such damage did not appear as a hydrogen signal on the TDS spectra. Second, interesting features observed on the TDS spectra of cold deformed ULC steel were further investigated by assessing the TDS spectra of recrystallised and annealed ULC steel. As such, the four peaks in the TDS spectra were linked to microstructural features: interstitial lattice positions, grain boundaries, dislocations and microvoids.     

Free radical scavenging and cytoprotective activities of phenolic antioxidants

The free radical scavenging activities of three flavonoids (quercetin, rutin and catechin) and four hydroxycinnamic acids (caffeic, ferulic, sinapic, and chlorogenic acids) were evaluated using both oxygen radical absorbance capacity (ORAC) and lipid peroxidation inhibition capacity (LPIC) assays. The cytoprotective effects of these compounds were also measured by the degree of protection against H(2)O(2)-induced damage of human Jurkat cells. All compounds exhibited protection against H(2)O(2)-mediated cytotoxicity in a dose-dependent manner. The concentrations required to result in a 50% reduction in cell death (EC(50) value) were calculated from their dose-response curves. These ranged from 0.15-2.65 microM. Overall, the four hydroxycinnamic acids tested were less effective than the three flavonoids, and of all compounds tested, quercetin offered the strongest protection against H(2)O(2)-induced cell death. A comparison of the results showed that the ability to inhibit peroxidation of lipids in a liposomal system (LPIC) correlated well with the cytoprotective activities (EC(50)), but not with the ability to protect an aqueous fluorescent substrate in the ORAC assays. The results suggest that the behavior of antioxidants in a liposomal membrane is to some extent similar to the mechanism involved in the protection of living cells from oxidative damage.     

Selection of Highly Proliferative and Multipotent Meniscus Progenitors through Differential Adhesion to Fibronectin: A Novel Approach in Meniscus Tissue Engineering

Meniscus injuries can be highly debilitating and lead to knee osteoarthritis. Progenitor cells from the meniscus could be a superior cell type for meniscus repair and tissue-engineering. The purpose of this study is to characterize meniscus progenitor cells isolated by differential adhesion to fibronectin (FN-prog). Human osteoarthritic menisci were digested, and FN-prog were selected by differential adhesion to fibronectin. Multilineage differentiation, population doubling time, colony formation, and MSC surface markers were assessed in the FN-prog and the total meniscus population (Men). Colony formation was compared between outer and inner zone meniscus digest. Chondrogenic pellet cultures were performed for redifferentiation. FN-prog demonstrated multipotency. The outer zone FN-prog formed more colonies than the inner zone FN-prog. FN-prog displayed more colony formation and a higher proliferation rate than Men. FN-prog redifferentiated in pellet culture and mostly adhered to the MSC surface marker profile, except for HLA-DR receptor expression. This is the first study that demonstrates differential adhesion to fibronectin for the isolation of a progenitor-like population from the meniscus. The high proliferation rates and ability to form meniscus extracellular matrix upon redifferentiation, together with the broad availability of osteoarthritis meniscus tissue, make FN-prog a promising cell type for clinical translation in meniscus tissue-engineering.     

Cytoprotective effects of polyphenolics on H<Subscript>2</Subscript>O<Subscript>2</Subscript>-induced cell death in SH-SY5Y cells in relation to their antioxidant activities

The cytoprotective effects of five flavonoids (quercetin, rutin, catechin, kaempferol and morin) and four hydroxycinnamic acids (caffeic, ferulic, sinapic and chlorogenic acids) were evaluated by the degree of protection they provided against H₂O₂-induced damage to human neuroblastoma SH-SY5Y cells. All compounds exhibited protection against H₂O₂-mediated cytotoxicity in a dose dependent manner. The concentration required to give a 50% reduction in cell death (EC₅₀ value) were derived from their dose–response relationships. The cytoprotective activities of these phenolic compounds in the order of quercetin > caffeic acid > rutin > chlorogenic acid > catechin > ferulic acid > sinapic acid > morin > kaempferol. The EC₅₀ values of the phenolic compounds were strongly related to their chemical structures. The EC₅₀ values were compared with the antioxidant activities as determined by five different chemically based antioxidant assays [2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP) and lipid peroxidation inhibition capacity (LPIC)]. The ability of these phenolic compounds to protect from H₂O₂-induced SH-SY5Y cell death correlated (r ² = 0.85) with their determined LPIC values and weakly (r ² = 0.44) with their ABTS activities. There was no correlation between EC₅₀ values and ORAC, FRAP or DPPH activities. The cytoprotection assay is a more biologically relevant measurement than the chemically defined antioxidant activity assays because it uses human cells as a substrate and therefore accounts for some aspects of uptake, metabolism and location of antioxidant compounds within cells.     

Spatial location memory discriminates children born at extremely low birth weight and late-preterm at age three.

Objective: The spatial location memory of preschool-aged children born preterm has rarely been studied primarily due to an absence of developmentally sensitive measures. This study aimed to address this gap in the literature. Method: We administered a modification of the Hopkins Board to 135 children at age 3 who were born extremely low birth weight (ELBW) (n = 20), late-preterm (LPT) (n = 75), or at term (TERM) (n = 40). Five measures were obtained: naming, trials-to-criterion, errors-to-criterion, delayed item recall, and delayed location recall. Results: ANCOVA indicated that the groups differed in naming (p = .019), errors-to-criterion (p = .002), and delayed item recall (p = .025). For these measures, ELBW performed worse than TERM and LPT, but LPT did not differ from TERM. Corrected age and sociodemographic factors did not eliminate the deficit in spatial location learning for ELBW participants. A MANCOVA found a significant difference in learning, with post hoc tests indicating significant learning across trials in the LPT and TERM groups, but not in the ELBW group. Conclusions: ELBW is a significant risk factor for developmental delay or impairment of spatial location learning. These findings suggest that the modified Hopkins Board identifies at-risk premature children. This modification may be more broadly useful to assess preschoolers' neurodevelopmental maturation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Einflüsse des geochemischen Milieus und der Eintragsform auf die Verteilung der anorganischen Redoxspezies des Arsens im Grundwasser

This study was initiated in order to investigate relationships between the arsenic species distribution, the geochemical conditions and the input source of As in groundwater. Water samples characterized in the study originated from four locations representing five different input sources. The redox conditions varied vrom oxid to sulfidic. Measurements indicate – as expected – that the As(III)/As(V)-species distribution is closely related to the redox environment. Nevertheless it cannot be predicted using the redox potenzial and the Nernst equation. Results clearly reveal a dependence of the species distribution on the As input species. Related to the redox conditions, an oxidation path of As(III) can be distinguished from a reductuion path of As(V). The kinetics of the redox reactions depend on the availability of reaction partners.