Особенности акушерско-гинекологического консультирования беременных, страдающих эпилепсией

БЕРЕМЕННОСТИ ОСЛОЖНЕНИЯЭПИЛЕПСИ

Evaluation of backbone-cyclized HER2-binding 2-helix Affibody molecule for In Vivo molecular imaging

Introduction Affibody molecules, small scaffold proteins, have demonstrated an appreciable potential as imaging probes. Affibody molecules are composed of three alpha-helices. Helices 1 and 2 are involved in molecular recognition, while helix 3 provides stability. The size of Affibody molecules can be reduced by omitting the third alpha-helix and cross-linking the two remaining, providing a smaller molecule with better extravasation and quicker clearance of unbound tracer. The goal of this study was to develop a novel 2-helix Affibody molecule based on backbone cyclization by native chemical ligation (NCL). Methods The HER2-targeting NCL-cyclized Affibody molecule ZHER2:342min has been designed, synthesized and site-specifically conjugated with a DOTA chelator. DOTA-ZHER2:342min was labeled with 111In and 68 Ga. The binding affinity of DOTA-ZHER2:342min was evaluated in vitro. The targeting properties of 111In- and 68 Ga-DOTA-ZHER2:342min were evaluated in mice bearing SKOV-3 xenografts and compared with the properties of 111In- and 68 Ga-labeled PEP09239, a DOTA-conjugated 2-helix Affibody analogue cyclized by a homocysteine disulfide bridge. Results The dissociation constant (KD) for DOTA-ZHER2:342min binding to HER2 was 18 nM according to SPR measurements. DOTA-ZHER2:342min was labeled with 111In and 68 Ga. Both conjugates demonstrated bi-phasic binding kinetics to HER2-expressing cells, with KD1 in low nanomolar range. Both variants demonstrated specific uptake in HER2-expressing xenografts. Tumor-to-blood ratios at 2 h p.i. were 6.1 ± 1.3 for 111In- DOTA-ZHER2:342min and 4.6 ± 0.7 for 68 Ga-DOTA-ZHER2:342min. However, the uptake of DOTA-ZHER2:342min in lung, liver and spleen was appreciably higher than the uptake of PEP09239-based counterparts. Conclusions Native chemical ligation enables production of a backbone-cyclized HER2-binding 2-helix Affibody molecule (ZHER2:342min) with low nanomolar target affinity and specific tumor uptake.NOTICE: this is the author's version of a work that was accepted for publication in Nuclear Medicine and Biology. Changes resulting from the publishing process, such as editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in:Honarvar H, Jokilaasko N, Andersson K, Malmberg J, Rosik D, Orlova A, Eriksson Karlström A, Tolmachev V, Järver P. Evaluation of Backbone-Cyclized HER2-Binding Two-Helix Affibody Molecule for In Vivo Molecular Imaging. Nucl Med Biol, 40,3, 2013 Apr; :378-86 DOI 10.1016/j.nucmedbio.2012.12.009.http://www.sciencedirect.com/science/article/pii/S0969805112003204</p

Surface coating of PLGA microparticles with protamine enhances their immunological performance through facilitated phagocytosis

Surface modifications of poly(lactide-co-glycolide) microparticles with different polycationic electrolytes have mainly been studied for conjugation to antigens and/or adjuvants. However, the in vivo immunological effects of using surface charged particles have not been address yet. In this study, microparticles were coated or not with protamine, a cationic and arginine-rich electrolyte that confers microparticles with a positively surface charge. We then evaluated the potential of protamine-coatings to assist the induction of immune responses in mice. Interestingly, enhanced antibodies and T-cell responses were observed in mice treated with the coated particles. In vitro studies suggested that the improved immunological performance was mediated by an increased uptake. Indeed, protamine-coated particles that carried a plasmid were even internalised into non-phagocytic cells and to cause their transfection. These results open the way for further research into a novel technology that combines the use protamine for facilitated cell penetration of that and biodegradable microparticles for prolonged antigen or drug release