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Measurement of Silver Nanolayer Absorption by the Body in an in Vivo Model of Inflammatory Gastrointestinal Diseases

Siczek K., Pawlak W., Zatorski H., Fichna J.

Metrology and Measurement Systems

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2016

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Vol. 23, nr 1

133--142

EN

Layers of silver particles are used in the studies on pathophysiology and treatment of diseases, both in pre-clinical and clinical conditions. Silver layers can be formed using different techniques and on different substrates. Deposition by magnetron sputtering on glass beads was used in this study. Silver absorption by the body was estimated by calculating the difference in thickness of the silver nanolayer deposited on a bead and measured before and after application of the bead in an animal model of gastrointestinal inflammation. Recommendations for the minimal thickness of silver nanolayer deposited on glass beads were worked out for further studies.

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Structural Studies of Position 2 Modified Endomorphin-2 Analogs by NMR Spectroscopy and Molecular Modeling

Janecka A., Perlikowska R., Gach K., Fichna J., Mazur A., Kruszyński R., Janecki T., Jankowski S.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 7

1293-1307

EN

Endomorphin-2 (EM-2, Tyr-Pro-Phe-Phe-NH2) is an endogenous ligand for the mi-opioid receptor. To examine the importance of Pro2 in EM-2 structure, we synthesized a series of analogs in corporating piperidine-2-, 3- and 4-carboxylic acids (Pip, Nip and Inp, respectively) in position 2. Pip, Nip and Inp are six-membered mimics of Pro and can be considered as alfa-, beta- and gamma-amino acids, respectively. Receptor binding studies revealed that [(R)-Nip2]EM-2 had greatly in creased mi-opioid receptor affinity compared with the parent peptide, while two other analogs were in active. In order to determine which structural elements of [(R)-Nip2]EM-2 could be responsible for the out standing affinity of this analog, the solution conformations of EM-2 analogs in corporating Promimics were investigated by the combination of 2D 1H NMR measurements and molecular modeling calculations. Evaluating the ratios of cis/trans rotamers, aromatic inter actions and dihedral angles we have found that all three analogs exist as a mixture of cis/trans rotamers of the Tyr–Xaa peptide bond and have flexible, extended conformations, with no intramolecular hydrogen bonds or aromatic ring inter actions observed for EM-2. The obtained results do not allow to draw conclusions on the bioactive conformation of the most active analog. We can suggest that a well known preference of the substituents to occupy equatorial positions in six-membered rings, to gether with a greater distance between Tyr1 and Phe3 aromatic rings, in Nip, which is a beta-amino acid, as compared with EM-2, are the main differentiating factors which are responsible for the exceptional affinity of [(R)-Nip2]EM-2.

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Synthesis of HYNIC- and DOTA-Conjugates with mi-Opioid Receptor Ligands: Morphiceptin and Endomorphin-2

Fichna J., Janecka A., Kosson P., Maecke H.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 7

951-959

EN

Opioid peptides recently attracted much attention as low molecular weight compounds, which can target malignant cells expressing opioid receptors on their cell surface. Therefore opioid peptides have a potential to be introduced as radiopharmaceuticals. In this paper, we describe the method of conjugation of two bifunctional chelating agents (BFCAs), hydrazinopyridine-3-carboxylic acid (HYNIC) and 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid (DOTA), to the N-terminal amino group of morphiceptin, endomorphin-2, and two of their analogs modified in position 3. GABA was used as a spacer molecule. mi-Opioid binding affinities of the peptides were compared with the binding affinities of BFCA-GABA-peptide conjugates. It was shown that the introduction of HYNIC to mi-opioid ligands causes only a slight decrease of -opioid receptor affinity, while DOTA-conjugates loose their affinity for mi-receptors completely.