Bidentate Ruthenium Vinylcarbene Catalysts derived from Enyne Metathesis

The preparation, structure, and catalytic activity of a series of bidentate η¹-vinylcarbene ruthenium complexes derived from the standard metathesis catalysts 1, 2, or 4 by enyne metathesis with phenylacetylene derivatives bearing an isopropoxy substituent at their ortho position are described. Terminal as well as non-terminal phenylacetylene derivatives react with similar ease, thus providing ample opportunity for the preparation of catalysts with tailor-made properties. Use of the silyl propargyl ether derivative 13b as the substrate results in the formation of complex 15, in which the silyl ether moiety rather than the isopropoxy substituent ligates the metal center. The structures of the new chelate complexes 6, 7, 9, 14, and 15 in the solid state were determined by X-ray crystallography

Radioligand binding studies of caloporoside and novel congeners with contrasting effects upon [35S] TBPS binding to the mammalian GABAA receptor

Caloporoside is a natural active fungal metabolite, which was isolated from Caloporous dichrous and was described to exhibit antibacterial, antifungal and phospholipase C inhibitory activity. We have previously reported evidence that related β-linked compounds, lactose and octyl-β-d-mannoside, bind and functionally modulate rodent GABAA receptors, respectively. We have characterized the binding pharmacology of synthetic caloporoside and two further congeners, 2-hydroxy-6-{[(16R)-(β-d-mannopyranosyloxy)heptadecyl]} benzoic acid and octyl-β-d-glucoside on GABAA receptors using a [35S]-t-butylbicyclophosphoorothionate (TBPS) radioligand binding assay. Caloporoside and 2-hydroxy-6-{[(16R)-(β-d-mannopyranosyloxy)heptadecyl]} benzoic acid produced concentration-dependent complete inhibition of specific [35S] TBPS binding with overall apparent IC50 values of 14.7 ± 0.1 and 14.2 ± 0.1 μM, respectively. In contrast, octyl-β-d-glucoside elicited a concentration-dependent stimulation of specific [35S] TBPS binding (Emax = 144 ± 4%; EC50 = 39.2 ± 22.7 nM). The level of stimulation was similar to that elicited by diazepam (Emax = 147 ± 6%; EC50 = 0.8 ± 0.1 nM), and was occluded by GABA (0.3 μM). However, the three test compounds failed to elicit any significant effect (positive or negative) upon [3H] flunitrazepam or [3H] muscimol binding, indicating that they did not bind directly, or allosterically couple, to the benzodiazepine or agonist binding site of the GABAA receptor, respectively. The constituent monosaccharide, glucose, and both the closely related congeners octyl-β-d-glucoside or hexyl-β-d-glucoside have no significant effect upon [35S] TBPS binding. These data, together, provide strong evidence that a β-glycosidic linkage and chain length are crucial for the positive modulation of [35S] TBPS binding to the GABAA receptor by this novel chemical class

The response of TL lithium fluoride detectors to 24 GeV/c protons for doses ranging up to 1 MGy

A new method of thermoluminescent (TL) measurement of radiation doses ranging from micrograys up to a megagray has been recently developed at IFJ. This method is based on a newly discovered behavior of LiF:Mg,Cu,P detectors at doses exceeding 1 kGy. Significant changes in their glow-curves are observed at higher doses; of special importance is occurrence of a new, well separated peak for doses above 50 kGy, thus these detectors can be used for measurements of doses at ultra-high dose range. In order to check the glow-curve features in the high dose region for different types of LiF:Mg,Cu,P and LiF:Mg,Ti detectors after irradiation with heavy charged particles, tests at the 24 GeV/c proton beam of IRRAD1 irradiation zone at the CERN Proton Synchrotron accelerator up to 1 MGy were performed. The occurrence of the high dose peak in the glow-curve of LiF:Mg,Cu,P detectors resulting from heavy particles irradiation was confirmed. Results of this investigation are presented in this paper. (C) 2010 Elsevier Ltd. All rights reserved

Regional Radiation Pneumonitis After SIRT of a Subcapsular Liver Metastasis: What is the Effect of Direct Beta Irradiation?

We herein present a patient undergoing selective internal radiation therapy with an almost normal lung shunt fraction of 11.5 %, developing histologically proven radiation pneumonitis. Due to a predominance of pulmonary consolidations in the right lower lung and its proximity to a large liver metastases located in the dome of the right liver lobe a Monte Carlo simulation was performed to estimate the effect of direct irradiation of the lung parenchyma. According to our calculations direct irradiation seems negligible and RP is almost exclusively due to ectopic draining of radioactive spheres