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Abstract  

Studies intended to optimize the production of Na18F, in aqueous solution following irradiation of organic fluorine compounds with 14 MeV neutrons are described. The use of Szilard-Chamers conditions was chosen to enhance the yield of18F, given the low fluxes available and the inherently low cross section of the (n, 2n) reaction. Twenty five potential target compounds were tested. The most suitable one, both in terms of the cost of the target material and of the efficiency of production of water-soluble Na18F, was found to be perfluoro n-hexane. A simple production method for18F is outlined.

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Abstract  

Prior work had documented that99mTcCl 6 2– could undergo ready ligand exchange reaction under non-aqueous condition. We now wish to report the ligand exchange reaction of bromine in99mTcBr 6 2– in non-aqueous solvents using 8-hydroxyquinoline (oxine) as the displacing ligand. Analysis of the products obtained by paper chromatography, HPLC and electrophoresis suggest that a 12 Tcoxine complex appears to be the most stable of the complexes formed, probably99mTc(oxine)2 Br2. However, displacement of bromine by polar solvents (both protic and aprotic) can also occur, both on99mTcBr 6 2– and in the above complex as a consequence of solvolytic reactions. Other Tc-oxine complexes can also be formed upon ligand exchange, but they appear to be stable only under aprotic, non solvolytic conditions. These studies again document that hexahalotechnetate complexes exhibit ligand exchange reactions under non-aqueous conditions, that they allow the ready synthesis of novel technetium complexes, but that because of their high reactivity the effect of competing reactions must be considered.

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Journal of Thermal Analysis and Calorimetry
Authors:
K. Kafarska
,
D. Czakis-Sulikowska
, and
W. Wolf

Abstract  

New metal(II) complexes with empirical formulae Co(ibup)2·4H2O, Cd(ibup)2·3H2O, Co(nap)2·H2O, Cd(nap)2·3H2O (where ibup=(CH3)2CHCH2C6H4CH(CH3COO) and nap=CH3O(C10H6)CH(CH3COO)) were isolated and investigated. The complexes were characterized by elemental analysis, molar conductance, IR spectroscopy and thermal decomposition. The thermal behavior was studied by TG, DTG, DTA methods under non-isothermal conditions in air atmosphere. The hydrated complexes lose water molecules in first step. All complexes decompose via intermediate products to corresponding metal oxides CoO and CdO. A coupled TG-MS system was used to detect the principal volatile products of thermolysis and fragmentation processes of Co(nap)2·H2O. The IR spectra of studied complexes revealed also absorption of the carboxylate group. Principal concern with the position of asymmetric, symmetric frequencies. The value of their separation allow to deduce about type of coordination these groups.

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Effect of carbodiimide as a coupling reagent on the metal binding properties of desferrioxamine

Model studies for the desferrioxamine — Human serum albumin conjugate

Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Janoki
,
J. Harwig
,
J. Slater
, and
W. Wolf

Abstract  

The effect of a carbodiimide on the gallium binding properties of desferrioxamine as a model for interpreting the low specific activity of gallium-labelled desferrioxamine-human serum albumin conjugate prepared using carbodiimide as the coupling reagent was studied. Desferrioxamine was treated with carbodiimide at various mole ratios and pH, before and after labeling with67Ga. Substantial loss of gallium binding capacity resulted when desferrioxamine was treated with carbodiimide prior to labeling, suggesting that the carbodiimide reacts with the hydroxamic acid groups of desferrioxamine and destroys their ability to bind gallium. No significant metal release occurred when desferrioxamine was labeled with gallium prior to carbodiimide treatment, indicating that the presence of the gallium protects the hydroxamic acid troups from the effects of carbodiimide. These results have important implications for preparing high-specific-activity radiopharmaceuticals using bifunctional chelation.

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Abstract

Purpose: To investigate the concentration of myocilin in the aqueous humor of open-angle glaucoma (OAG) patients, including correlations with glaucoma subtypes and intraocular pressure (IOP). Patients and Methods: The study comprised 85 patients with OAG. Glaucoma subtypes included 35 cases of high tension glaucoma (HTG), 25 cases of normal tension glaucoma (NTG), and 25 cases of exfoliation glaucoma (ExG). Forty-five patients with senile cataract were included as control. The concentrations of myocilin in the aqueous humor were measured by plotting the densitometry readings of the aqueous humor samples against a recombinant myocilin standard curve. Additionally, the relationships with the glaucoma subtypes, IOP, and glaucoma severity were analyzed. Results: A significantly higher percentage of patients in the glaucoma subgroups were positive for myocilin compared with the cataract group. The mean myocilin concentrations among the glaucoma positive case subgroups were not different (P=0.326). Myocilin levels were significantly higher in human HTG compared with cataract group (P<0.05). There were no significant correlations between the myocilin concentration and the IOP or the severity of glaucoma. Conclusion: Myocilin-positive patients were significant in the glaucoma subgroups than in the cataract group, with a highly significant difference observed for HTG patients.

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Abstract

Rapid detection of antibiotic resistances of clinical bacterial strains would allow an early selective antibiotic therapy and a faster intervention and implementation of infection control measurements. In clinical practice, however, conventional antibiotic susceptibility tests of bacteria often need 24 h until the results are obtained. The metabolic heat production of bacteria is an excellent possibility to record their physiological activities and could therefore be used for a rapid discrimination of bacterial strains which are resistant or non-resistant to antibiotics and also to lytic bacteriophages, respectively. Unfortunately, conventional calorimeters suffer from need of comparably large volumes of bacterial suspensions are characterised by slow operation and high costs which restrict their application in clinical laboratories. The present paper demonstrates that a new type of calorimeters developed on silicon-chip technology enables the detection of antibiotic resistances on a minute-timescale. For this reasons, a prototype chip calorimeter was used which sensitivity is 20 nW related to the heat production of about 104 bacteria. For a clear discrimination of antibiotic resistance about 105 bacteria are required. The antibiotic resistances and susceptibilities of different strains of Staphylococcus aureus to cefoxitin and the sensitivities of S. aureus DSM 18421 and E. coli DSM 498 to a mixture of two bacteriophages were studied. Comparing the heat productions of cultures incubated with antibiotics or bacteriophages to those without these antibacterial preparations enabled a clear discrimination of resistant and non-resistant strains already after totally 2 h.

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