Διερεύνηση της επίδρασης της χορήγησης του λιποϊκού οξεος per-os σε σειρά δερματοκοσμητολογικών παραμέτρων

Στην παρούσα διατριβή αναπτύχθηκε μία αναλυτική μέθοδος με υγροχρωματογραφία αντίστροφης φάσης και ανιχνευτή UV για τον προσδιορισμό, τόσο του α-LA στο συμπλήρωμα διατροφής (καψάκι 120 mg), όσο και στην κρέμα με α-LA 1.5 % w/w. H μέθοδος ήταν γρήγορη, ακριβής, ανθεκτική, εκλεκτική, επαναλήψιμη και αξιόπιστη και για τα δύο είδη προϊόντων και επικυρώθηκε, σύμφωνα με τις οδηγίες της ΙCH Q2 (R1): International Conference on Harmonization. (2005). Επιπλέον, διεξήχθη μία τυχαιοποιημένη, διπλά τυφλή, σε παράλληλες ομάδες κλινική μελέτη για χρονικό διάστημα δύο μηνών, όπου μελετήθηκε η επίδραση του α-λιποϊκού οξέος (α-LA) σε είκοσι εθελοντές, σε σειρά δερματοκοσμητολογικών παραμέτρων με τη χρήση in-vivo μεθόδων (βιοφυσικές) και με ex-vivo μεθόδους (βιοψίες). Χρησιμοποιήθηκαν οι βιοφυσικές μέθοδοι για την αξιολόγηση της μικροτοπογραφίας του δέρματος (απαλότητα και μείωση των λεπτών γραμμών) και ελήφθησαν βιοψίες, προκειμένου να μελετηθεί η πιθανή αύξηση του κολλαγόνου στο χόριο (θηλώδες) του δέρματος, στην αρχή και στο τέλος της θεραπείας. Επιπλέον, μελετήθηκαν και αξιολογήθηκαν κλινικά οι πιθανές ανεπιθύμητες ενέργειες στους εθελοντές, από τοξικολογικής πλευράς, πριν την μελέτη με εφαρμογή με «Patch test 48h» και κατά την διενέργειά της. Τέλος, μελετήθηκε η σταθερότητα του δραστικού συστατικού (α-LA) στα προϊόντα, τόσο της κρέμας, όσο και του συμπληρώματος διατροφής, μετά από εξαναγκασμένες συνθήκες διάσπασης, επιταχυνόμενης και μακροχρόνιας γήρανσης.In this doctoral thesis an analytical method was developed with reversed phase liquid chromatography and UV detection for the determination of both α-LA dietary supplement (capsule 120 mg) and cream with 1,5 % w/w. The method proved to be accurate, robust, selective, precise in both types of products and validated according to ΙCH Q2 (R1): International Conference on Harmonization. (2005). Furthermore, a randomized double blide study, parallel groups, clinical study conducted for two months, where the efficacy of α-Lipoic acid was studied in twenty subjects, for the evaluation of dermatocosmetic parameters by in-vivo (biophysical) and ex-vivo methods (biopsies). Biophysical methods were used for the evaluation of microtopography of skin (smoothness, decrease of fine lines) and biopsies were received, in order to study the possible increase of collagen in dermis (papillary) of skin, at the beginning of study and at the end. Moreover, the possible adverse events were studied and evaluated clinically to subjects, from the toxicological point of view, before the study with a Patch test 48h and during the study. Additionally, the stability of active substance (α-LA) was studied in both cream and dietary supplement after forced degradation conditions of accelerated and long term aging

Progressive Phosphorylation Modulates the Self-Association of a Variably Modified Histone H3 Peptide

Protein phosphorylation is a key regulatory mechanism in eukaryotic cells. In the intrinsically disordered histone tails, phosphorylation is often a part of combinatorial post-translational modifications and an integral part of the “histone code” that regulates gene expression. Here, we study the association between two histone H3 tail peptides modified to different degrees, using fully atomistic molecular dynamics simulations. Assuming that the initial conformations are either α-helical or fully extended, we compare the propensity of the two peptides to associate with one another when both are unmodified, one modified and the other unmodified, or both modified. The simulations lead to the identification of distinct inter- and intramolecular interactions in the peptide dimer, highlighting a prominent role of a fine-tuned phosphorylation rheostat in peptide association. Progressive phosphorylation appears to modulate peptide charge, inducing strong and specific intermolecular interactions between the monomers, which do not result in the formation of amorphous or ordered aggregates, as documented by experimental evidence derived from Circular Dichroism and NMR spectroscopy. However, upon complete saturation of positive charges by phosphate groups, this effect is reversed: intramolecular interactions prevail and dimerization of zero-charge peptides is markedly reduced. These findings underscore the role of phosphorylation thresholds in the dynamics of intrinsically disordered proteins. Phosphorylation rheostats might account for the divergent effects of histone modifications on the modulation of chromatin structure

Structure based inhibitor design targeting glycogen phosphorylase b. Virtual screening, synthesis, biochemical and biological assessment of novel N-acyl-β-d-glucopyranosylamines

Glycogen phosphorylase (GP) is a validated target for the development of new type 2 diabetes treatments. Exploiting the Zinc docking database, we report the in silico screening of 1888 β- D-glucopyranose-NH-CO-R putative GP inhibitors differing only in their R groups. CombiGlide and GOLD docking programs with different scoring functions were employed with the best performing methods combined in a “consensus scoring” approach to ranking of ligand binding affinities for the active site. Six selected candidates from the screening were then synthesized and their inhibitory potency was assessed both in vitro and ex vivo. Their inhibition constants’ values, in vitro, ranged from 5 to 377 µM while two of them were effective at causing inactivation of GP in rat hepatocytes at low µM concentrations. The crystal structures of GP in complex with the inhibitors were defined and provided the structural basis for their inhibitory potency and data for further structure based design of more potent inhibitors

A biophysical mechanism may control the collinearity of <it>Hoxd </it>genes during the early phase of limb development

Abstract A biophysical model has been proposed which deals with the observed collinearity of Hox gene expressions in developing vertebrate limbs. It is assumed that physical forces gradually dislocate the genes of the Hoxd cluster from inside the chromosome territory into the interchromosome domain, where the genes are activated. In particular, the action of Coulomb electric forces has been estimated in detail. Genetic engineering experiments (deletions, duplications and transpositions) were recently reported for Hoxd expression during limb development. Here, we analyse these results and show that the biophysical model explains them successfully.</p

Research of effect of per os administration of lipoic acid in a series of dermocosmetic parameters

In this doctoral thesis an analytical method was developed with reversed phase liquid chromatography and UV detection for the determination of both α-LA dietary supplement (capsule 120 mg) and cream with 1,5 % w/w. The method proved to be accurate, robust, selective, precise in both types of products and validated according to ΙCH Q2 (R1): International Conference on Harmonization. (2005). Furthermore, a randomized double blide study, parallel groups, clinical study conducted for two months, where the efficacy of α-Lipoic acid was studied in twenty subjects, for the evaluation of dermatocosmetic parameters by in-vivo (biophysical) and ex-vivo methods (biopsies). Biophysical methods were used for the evaluation of microtopography of skin (smoothness, decrease of fine lines) and biopsies were received, in order to study the possible increase of collagen in dermis (papillary) of skin, at the beginning of study and at the end. Moreover, the possible adverse events were studied and evaluated clinically to subjects, from the toxicological point of view, before the study with a Patch test 48h and during the study. Additionally, the stability of active substance (α-LA) was studied in both cream and dietary supplement after forced degradation conditions of accelerated and long term aging.Στην παρούσα διατριβή αναπτύχθηκε μία αναλυτική μέθοδος με υγροχρωματογραφία αντίστροφης φάσης και ανιχνευτή UV για τον προσδιορισμό, τόσο του α-LA στο συμπλήρωμα διατροφής (καψάκι 120 mg), όσο και στην κρέμα με α-LA 1.5 % w/w. H μέθοδος ήταν γρήγορη, ακριβής, ανθεκτική, εκλεκτική, επαναλήψιμη και αξιόπιστη και για τα δύο είδη προϊόντων και επικυρώθηκε, σύμφωνα με τις οδηγίες της ΙCH Q2 (R1): International Conference on Harmonization. (2005). Επιπλέον, διεξήχθη μία τυχαιοποιημένη, διπλά τυφλή, σε παράλληλες ομάδες κλινική μελέτη για χρονικό διάστημα δύο μηνών, όπου μελετήθηκε η επίδραση του α-λιποϊκού οξέος (α-LA) σε είκοσι εθελοντές, σε σειρά δερματοκοσμητολογικών παραμέτρων με τη χρήση in-vivo μεθόδων (βιοφυσικές) και με ex-vivo μεθόδους (βιοψίες). Χρησιμοποιήθηκαν οι βιοφυσικές μέθοδοι για την αξιολόγηση της μικροτοπογραφίας του δέρματος (απαλότητα και μείωση των λεπτών γραμμών) και ελήφθησαν βιοψίες, προκειμένου να μελετηθεί η πιθανή αύξηση του κολλαγόνου στο χόριο (θηλώδες) του δέρματος, στην αρχή και στο τέλος της θεραπείας. Επιπλέον, μελετήθηκαν και αξιολογήθηκαν κλινικά οι πιθανές ανεπιθύμητες ενέργειες στους εθελοντές, από τοξικολογικής πλευράς, πριν την μελέτη με εφαρμογή με «Patch test 48h» και κατά την διενέργειά της. Τέλος, μελετήθηκε η σταθερότητα του δραστικού συστατικού (α-LA) στα προϊόντα, τόσο της κρέμας, όσο και του συμπληρώματος διατροφής, μετά από εξαναγκασμένες συνθήκες διάσπασης, επιταχυνόμενης και μακροχρόνιας γήρανσης

Disappearance of Temporal Collinearity in Vertebrates and Its Eventual Reappearance

It was observed that a cluster of ordered genes (Hox1, Hox2, Hox3…) in the genome are activated in the ontogenetic units (1, 2, 3 …) of an embryo along the Anterior/Posterior axis following the same order of the Hox genes. This Spatial Collinearity (SC) is very strange since it correlates events of very different spatial dimensions. It was later observed in vertebrates, that, in the above ordering, first is Hox1expressed in ontogenetic unit 1, followed later by Hox2 in unit 2 and even later Hox3 in unit 3. This temporal collinearity (TC) is an enigma and even to-day is explored in depth. In 1999 T. Kondo and D. Duboule, after posterior upstream extended DNA excisions, concluded that the Hox cluster behaves ‘as if’ TC disappears. Here the consideration of TC really disappearing is taken face value and its repercussions are analyzed. Furthermore, an experiment is proposed to test TC disappearance. An outcome of this experiment could be the reappearance (partial or total) of TC

Physical Laws Shape Up HOX Gene Collinearity

Hox gene collinearity (HGC) is a multi-scalar property of many animal phyla particularly important in embryogenesis. It relates entities and events occurring in Hox clusters inside the chromosome DNA and in embryonic tissues. These two entities differ in linear size by more than four orders of magnitude. HGC is observed as spatial collinearity (SC), where the Hox genes are located in the order (Hox1, Hox2, Hox3 …) along the 3′ to 5′ direction of DNA in the genome and a corresponding sequence of ontogenetic units (E1, E2, E3, …) located along the Anterior—Posterior axis of the embryo. Expression of Hox1 occurs in E1, Hox2 in E2, Hox3 in E3, etc. Besides SC, a temporal collinearity (TC) has been also observed in many vertebrates. According to TC, first Hox1 is expressed in E1; later, Hox2 is expressed in E2, followed by Hox3 in E3, etc. Lately, doubt has been raised about whether TC really exists. A biophysical model (BM) was formulated and tested during the last 20 years. According to BM, physical forces are created which pull the Hox genes one after the other, driving them to a transcription factory domain where they are transcribed. The existing experimental data support this BM description. Symmetry is a physical–mathematical property of matter that was explored in depth by Noether who formulated a ground-breaking theory (NT) that applies to all sizes of matter. NT may be applied to biology in order to explain the origin of HGC in animals developing not only along the A/P axis, but also to animals with circular symmetry