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Mitotic spindle inhibitors (colchicine, vinblastine, vincristine, 020, ethanol) and cytochalasin B inhibit the phagocytosis of colloid by thyroid cells and the secretion of thyroid hormones. This inhibition has been linked to interferences with the microtubular microfilament system of the follicular cell. In order to test the possibility of using such inhibitors to selectively block secretion, the action of suppressing or highly inhibitory concentrations on other metabolic parameters has been studied on dog thyroid slices in vitro: glucose oxidation, lactate formation, iodide binding to protein, cyclic 3'5' AMP accumulation. It is shown that at a concentration of 10 mM colchicine is entirely non specific as it greatly inhibits all facets of metabolism and all the stimulatory effects of cyclic 3'5' AMP and thyrotropin. The other mictrotubule inhibitors, although affecting thyroid metabolism in various ways were more specified. The enhancement by vineblastine of glucose oxidation ald iodine binding to proteins suggests an activation of they thyroid H2O2 generating system. D2O on the other hand selectively inhibits secretion and the binding of iodide to proteins. Cytochalasin B, presumably by inhibiting hexose transport, decreased glycolysis and the uptake of iodide. However this effect cannot account for the complete inhibition of thyroid secretion.

Arabinoxylan (AX) is among the most abundant hemicelluloses on earth and one of the major components of feedstocks that are currently investigated as a source for advanced biofuels. As global research into these sustainable biofuels is increasing, scientific knowledge about the enzymatic breakdown of AX advanced significantly over the last decade. This review focuses on the exo-acting AX hydrolases, such as α-arabinofuranosidases and β-xylosidases. It aims to provide a comprehensive overview of the diverse substrate specificities and corresponding structural features found in the different glycoside hydrolase families. A careful review of the available literature reveals a marked difference in activity between synthetically labeled and naturally occurring substrates, often leading to erroneous enzymatic annotations. Therefore, special attention is given to enzymes with experimental evidence on the hydrolysis of natural polymers.

Neutron dosimetry intercomparison studies have been undertaken at the Nice neutrontherapy facility with the staff at Louvain-la-Neuve which has had wide experience in both dosimetric and radiobiological intercomparisons. Tissue equivalent (TE) ionization chambers were first calibrated in 60Co beams and then exposed in the neutron beam at different depths in a water phantom; the largest difference observed in neutron beam measurements with all the chambers tested was 0.89%, and most of them agreed to within less than 0.5%. The gamma component at four depths was derived from measurements with Geiger-Müller counters; the results obtained with the two counters (Nice and Louvain-la-Neuve), expressed as a percentage of the total dose (neutron + gamma), agreed to within less than 0.03% and the value increased from 1.4 to 4.2% between 2 and 20 cm in depth.

Deletion of both iclR and arcA in E. coli profoundly alters the central metabolic fluxes and decreases acetate excretion by 70%. In this study we investigate the metabolic consequences of both deletions in E. coli BL21 (DE3). No significant differences in biomass yields, acetate yields, CO(2) yields and metabolic fluxes could be observed between the wild type strain E. coli BL21 (DE3) and the double-knockout strain E. coli BL21 (DE3) ΔarcAΔiclR. This proves that arcA and iclR are poorly active in the BL21 wild type strain. Noteworthy, both strains co-assimilate glucose and acetate at high glucose concentrations (10-15 g l(-1)), while this was never observed in K12 strains. This implies that catabolite repression is less intense in BL21 strains compared to in E. coli K12.

SCOPUS: ar.j ; info:eu-repo/semantics/published

This study was initiated following conclusions from earlier experimental work, performed in a low-energy carbon ion beam, indicating a significant LET dependence of the response of a PTW-60019 microDiamond detector. The purpose of this paper is to present a comparison between the response of the same PTW-60019 microDiamond detector and an IBA Roos-type ionization chamber as a function of depth in a 62MeV proton beam. Even though proton beams are considered as low linear energy transfer (LET) beams, the LET value increases slightly in the Bragg peak region. Contrary to the observations made in the carbon ion beam, in the 62MeV proton beam good agreement is found between both detectors in both the plateau and the distal edge region. No significant LET dependent response of the PTW-60019 microDiamond detector is observed consistent with other findings for proton beams in the literature, despite this particular detector exhibiting a substantial LET dependence in a carbon ion beam.

FLWIN ; info:eu-repo/semantics/published

The magnitude, direction, and time course of the effects of acute administration of ethanol (0.1 or 1.0 g/kg) on the extracellular levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and GABA within the nucleus accumbens of the rat were analysed using microdialysis in conjunction with high-pressure liquid chromatography and electrochemical detection. IP injection of 0.1 g/kg ethanol failed to modify the extracellular concentration of DA, DOPAC, HVA, 5-HT, 5-HIAA, and GABA in the nucleus accumbens during the 120-min collection period. On the contrary, 1.0 g/kg IP ethanol significantly increased extracellular levels of DA, DOPAC, and 5-HIAA in microdialysates from the nucleus accumbens. The maximal increase in DA (314.87 +/- 6%), DOPAC (210.58 +/- 3%), and 5-HIAA (250.88 +/- 8%) was observed 40 min after administration of ethanol. Extracellular HVA was also enhanced (220.89 +/- 2%) at time point 100 min following injection of the same dose of ethanol. Finally, extracellular levels of 5-HT and GABA remained unchanged following 1.0 g/kg ethanol.