54 research outputs found

    Toxic effects of Pb2+ on the growth and mineral nutrition of signal grass (Brachiaria decumbens) and Rhodes grass (Chloris gayana)

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    Although grasses are commonly used to revegetate sites contaminated with lead (Pb), little is known regarding the Pb-tolerance of many of these species. Using dilute solution culture to mimic the soil solution, the growth of signal grass (Brachiaria decumbens Stapf cv. Basilisk) and Rhodes grass (Chloris gayana Kunth cv. Pioneer) was related to the mean activity of Pb2+ {Pb2+} in solution. There was a 50% reduction in fresh mass of signal grass shoots at 5 mu M {Pb2+} and at 3 mu M {Pb2+} for the roots. Rhodes grass was considerably more sensitive to Pb in solution, with shoot and root fresh mass being reduced by 50% at 0.5 mu M {Pb2+}. The higher tolerance of signal grass to Pb appeared to result from the internal detoxification of Pb, rather than from the exclusion of Pb from the root. At toxic {Pb2+}, an interveinal chlorosis developed in the shoots of signal grass (possibly a Pb-induced Mn deficiency), whilst in Rhodes grass, Pb2+ caused a bending of the root tips and the formation of a swelling immediately behind some of the root apices. Root hair growth did not appear to be reduced by Pb2+ in solution, being prolific at all {Pb2+} in both species

    Macrophage Migration Inhibitory Factor Antagonist Blocks the Development of Endometriosis In Vivo

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    Endometriosis, a disease of reproductive age women, is a major cause of infertility, menstrual disorders and pelvic pain. Little is known about its etiopathology, but chronic pelvic inflammation is a common feature in affected women. Beside symptomatic treatment of endometriosis-associated pain, only two main suboptimal therapeutic approaches (hormonal and invasive surgery) are generally recommended to patients and no specific targeted treatment is available. Our studies led to the detection of a marked increase in the expression of macrophage migration inhibitory factor (MIF) in the eutopic endometrium, the peripheral blood and the peritoneal fluid of women with endometriosis, and in early, vascularized and active endometriotic lesions. Herein, we developed a treatment model of endometriosis, where human endometrial tissue was first allowed to implant into the peritoneal cavity of nude mice, to assess in vivo the effect of a specific antagonist of MIF (ISO-1) on the progression of endometriosis and evaluate its efficacy as a potential therapeutic tool. Administration of ISO-1 led to a significant decline of the number, size and in situ dissemination of endometriotic lesions. We further showed that ISO-1 may act by significantly inhibiting cell adhesion, tissue remodeling, angiogenesis and inflammation as well as by altering the balance of pro- and anti-apoptotic factors. Actually, mice treatment with ISO-1 significantly reduced the expression of cell adhesion receptors αv and ß3 integrins (P<0.05), matrix metalloproteinases (MMP) 2 and 9 (P<0.05), vascular endothelial cell growth factor (VEGF) (P<0.01), interleukin 8 (IL8) (P<0.05), cyclooxygenease (COX)2 (P<0.001) and the anti-apoptotic protein Bcl2 (P<0.01), but significantly induced the expression of Bax (P<0.05), a potent pro-apoptotic protein. These data provide evidence that specific inhibition of MIF alters endometriotic tissue growth and progression in vivo and may represent a promising potential therapeutic avenue

    Quantum Groups, Braiding Matrices and Coset Models

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    We discuss a few results on quantum groups in the context of rational conformal field theory with underlying affine Lie algebras. A vertex-height correspondence - a well-known procedure in solvable lattice models - is introduced in the WZW theory. This leads to a new definition of chiral vertex operator in which the zero mode is given by the q-Clebsch Gordan coefficients. Braiding matrices of coset models are found to factorize into those of the WZW theories. We briefly discuss the construction of the generators of the universal enveloping algebra in Toda field theories. 21 refs., 2 figs

    Development and initial evaluation of diversity array technology for soybean and mungbean

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    Diversity Array Technology (DArT), a technique for quickly generating large numbers of molecular markers, was established for two legume crops, soybean (Glycine max) and mungbean (Vigna radiata). For each crop, two genomic complexity reduction methods, utilizing PstI/TaqI and PstI/BstNI restriction digests, were selected for DNA clonal library development and for the isolation in each case of 7,680 DArT clones from genomic representations of pooled DNA samples. While the PstI/BstNI method produced more polymorphic clones than PstI/TaqI for the soybean library, there was no significant difference between the two methods for the mungbean library. Polymorphism frequencies in mungbean were around twice those in soybean, reflecting greater diversity in the mungbean samples. Even so, there were still nearly 1,500 unique polymorphic clones identified for soybean. The DArT marker transferability from soybean to mungbean (13.6%) was nearly five times higher than that from mungbean to soybean (3.1%). The percentage of DArT marker transferability between mungbean and several other Vigna species ranged from 3.4 to 20.2%. The genetic similarities among 11 diverse Vigna spp. samples, evaluated using the DArT mungbean library, were consistent with published information on these taxa. The results indicated that for soybean and mungbean, the DArT technique is an effective tool for marker generation in terms of speed and the numbers of markers identified. The transferability of markers between soybean and mungbean indicated that DArT may be useful for comparative genomic studies, while the ability of the mungbean library to discriminate between related Vigna taxa suggested that DArT may also be useful for studies of genetic diversity

    Multichannel intraluminal impedance 7 and pH monitoring (pH-MII) in infants and children

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    The application of combined pH and multichannel intraluminal impedance (pH-MII) monitoring has enhanced the recognition and characterization of gastro-oesophageal reflux disease (GORD). Its main advantages over traditional pH monitoring lie in the additional ability to detect non-acid gastro-oesophageal reflux (GOR), to discern between liquid and gas GOR and to determine the proximal extent of a GOR episode. When conducted in combination with manometry, it reveals information on the relationship between oesophageal pressures and oesophageal bolus flow, enhancing the evaluation of oesophageal function testing in terms of assessment of mechanisms of oesophageal bolus clearance. The measurement of mean impedance baseline has also provided novel insights into oesophageal mucosal integrity changes as an indicator of oesophageal inflammation. However, a few clinical and technical shortcomings, of which some are specific to the paediatric population, must be considered when interpreting study results and limit the diagnostic value of pH-MII monitoring in children. In this chapter, the technical aspects of pH-MII monitoring will therefore first be addressed, and, second, the current clinical benefits and limitations of oesophageal pH-MII in children will be highlighted
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