Compartmental modeling of 11C-HOMADAM binding to the serotonin transporter in the healthy human brain.
ABSTRACT The novel PET radioligand (11)C-N,N-dimethyl-2-(2'-amino-4'-hydroxymethylphenylthio)benzylamine ((11)C-HOMADAM) binds with high affinity and selectively to the serotonin transporter (SERT). The purpose of this study was to develop a reliable kinetic model to describe the uptake of (11)C-HOMADAM in the healthy human brain.
Eight volunteers participated in the study; 5 of them were fitted with arterial catheters for blood sampling and all were scanned on a high-resolution research tomograph after the injection of (11)C-HOMADAM. Regional distribution volumes and binding potentials were calculated with 2- and 4-parameter arterial-input compartment models, a 3-parameter reference tissue compartment model, and the Logan graphic approach.
The 2-parameter arterial-input compartment model was statistically superior to the 4-parameter model and described all brain regions. Calculated binding potentials agreed well between the arterial-input model and the reference tissue model when the cerebellum was used as the reference tissue. The Logan graphic approach was not able to estimate the higher concentration of SERT in the dorsal raphe than in the midbrain.
(11)C-HOMADAM is a highly promising radioligand with high ratios of specific binding to nonspecific binding in known SERT-rich structures, such as the raphe nuclei. The 3-parameter reference tissue model approach permits a simplified quantitatively accurate method for estimating SERT binding potentials.
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ABSTRACT: The study of many biological systems requires the application of a compartmental analysis, together with the use of isotopic tracers, parameter identification and methods to evaluate the mean parameters. For all this, the kinetic equations of the compartmental system as a function of its parameters are needed. In this paper, we present some considerations on the diagrams of connectivity of linear compartmental systems and obtain new properties from the matrix corresponding to the ordinary first-order linear differential equation systems which describe their kinetic behaviour. Using these properties, symbolic equations are obtained in a simplified form. These equations provide the instantaneous amount of substance in any compartment of the system when zero input is injected into one or more of the system compartments, solely as a function of those parameters of compartmental systems which really have an influence on the sought expression. This is unlike what happens in the other symbolic equations obtained in a previous contribution that included all the fractional transfer coefficients involved in the compartmental system, regardless of whether or not they had an influence on the instantaneous amount of substance.Journal of Mathematical Chemistry 01/2012; 50(6). · 1.23 Impact Factor
Conference Paper: The design of new, Pb-free solder alloys with improved properties[Show abstract] [Hide abstract]
ABSTRACT: The goal of the research presented in this paper is to identify Pb-free alloys with melting temperatures close to or lower than that of the near-eutectic 40Pb-60Sn solder (melting point of 183°C), and that with the best mechanical properties. We have obtained substantially improved mechanical properties through manipulation of alloy microstructures. The following three alloys with superior mechanical properties are discussed: i) Sn-3.5%Ag-1%Zn-0.5%Cu with a melting point of ~216°C, ii) Sn-8%Zn-5%In-(0.1-0.5%)Ag with a melting point of ~187°C, and iii) 54.5%Bi-45%Sn-0.5%Ag with a melting point of ~140°CElectronics and the Environment, 1995. ISEE., Proceedings of the 1995 IEEE International Symposium on; 06/1995
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ABSTRACT: [(18) F]2-Fluoroethyl-p-toluenesulfonate also called [(18) F]2-fluoroethyl tosylate has been widely used for labeling radioligands for positron emission tomography (PET). [(18) F]2-Fluoroethyl-4-bromobenzenesulfonate, also called [(18) F]2-fluoroethyl brosylate ([(18) F]F(CH2 )2 OBs), was used as an alternative radiolabeling agent to prepare [(18) F]FEOHOMADAM, a fluoroethoxy derivative of HOMADAM, by O-fluoroethylating the phenolic precursor. Purified by reverse-phase HPLC, the no-carrier-added [(18) F]F(CH2 )2 OBs was obtained in an average radiochemical yield (RCY) of 35%. The reaction of the purified and dried [(18) F]F(CH2 )2 OBs with the phenolic precursor was performed by heating in DMF and successfully produced [(18) F]FEOHOMADAM, after HPLC purification, in RCY of 21%. Copyright © 2013 John Wiley & Sons, Ltd.Journal of Labelled Compounds 09/2013; 56(11):539-543.