Ligand-receptor interaction modelling using PET imaging

A basic problem in the discovery and development of novel drugs to be used in the treatment of neurological and psychiatric disorders is the absence of relevant in vitro or in vivo animal models that can yield results which can be extrapolated to man. Drug research now benefits from the fast development of functional imaging techniques such as positron emission tomography (PET) which trace radiolabelled molecules directly in the human brain. PET uses molecules that are labelled with short-lived radionuclides and injected intravenously into experimental animals, human volunteers or patients. The current work provided novel knowledge in the ligand-receptor interaction between GR205171 and neurokinin 1 (NK1) receptor. GR205171 is a high affinity and selective NK1-receptor antagonist. Clinical studies were performed both in monkeys and humans to obtain information about the suitability of the ligand with regard to its affinity and penetration. The specific objectives of this thesis were to define an appropriate model for GR205171 tracer and to calculate receptor occupancy in the monkey and human brain, introducing also novel methodological approaches. The definition of a relationship between plasma drug concentration and receptor occupancy was another important aim of this work. In fact, the demonstration of quantitative relationships between drug binding in vivo from plasma concentration data and drug effects in patients can be used to validate targets for drug action, to correlate pharmacological and physiological effects, and to optimise clinical treatment. In conclusion, the modelling of GR205171 PET data, including different methodological approaches, demonstrated its utility in assessing NK1 receptor occupancy after drug challenge and its relationship with plasma concentration

An efficient algorithm to perform local concerted movements of a chain molecule

The devising of efficient concerted rotation moves that modify only selected local portions of chain molecules is a long studied problem. Possible applications range from speeding the uncorrelated sampling of polymeric dense systems to loop reconstruction and structure refinement in protein modeling. Here, we propose and validate, on a few pedagogical examples, a novel numerical strategy that generalizes the notion of concerted rotation. The usage of the Denavit-Hartenberg parameters for chain description allows all possible choices for the subset of degrees of freedom to be modified in the move. They can be arbitrarily distributed along the chain and can be distanced between consecutive monomers as well. The efficiency of the methodology capitalizes on the inherent geometrical structure of the manifold defined by all chain configurations compatible with the fixed degrees of freedom. The chain portion to be moved is first opened along a direction chosen in the tangent space to the manifold, and then closed in the orthogonal space. As a consequence, in Monte Carlo simulations detailed balance is easily enforced without the need of using Jacobian reweighting. Moreover, the relative fluctuations of the degrees of freedom involved in the move can be easily tuned. We show different applications: the manifold of possible configurations is explored in a very efficient way for a protein fragment and for a cyclic molecule; the "local backbone volume", related to the volume spanned by the manifold, reproduces the mobility profile of all-α helical proteins; the refinement of small protein fragments with different secondary structures is addressed. The presented results suggest our methodology as a valuable exploration and sampling tool in the context of bio-molecular simulations

The Formal Dynamism of Categories: Stops vs. Fricatives, Primitivity vs. Simplicity

Minimalist Phonology (MP; Pöchtrager 2006) constructs its theory based on the phonological epistemological principle (Kaye 2001) and exposes the arbitrary nature of standard Government Phonology (sGP) and strict-CV (sCV), particularly with reference to their confusion of melody and structure. For Pöchtrager, these are crucially different, concluding that place of articulation is melodic (expressed with elements), while manner of articulation is structural. In this model, the heads (xN and xO) can license and incorporate the length of the other into their own interpretation, that is xN influences xO projections as well as its own and vice versa. This dynamism is an aspect of the whole framework and this paper in particular will show that stops and fricatives evidence a plasticity of category and that, although fricatives are simpler in structure, stops are the more primitive of the two. This will be achieved phonologically through simply unifying the environment of application of the licensing forces within Pöchtrager's otherwise sound onset structure. In doing so, we automatically make several predictions about language acquisition and typology and show how lenition in Qiang (Sino-Tibetan) can be more elegantly explained

Integration of ground remote sensing surveys and archaeological excavation to characterize the medieval mound (Scarlino, Tuscany-Italy)

The landscape of Scarlino (Grosseto, Italy) has been studied by the Department of Archaeology (University of Siena) since 1979. The archaeological site was identified in vertical air photos, but the unavailability of GPS devices at the time made location in the field difficult. Aerial photo analysis allowed us to interpret the evidence as a triple enclosure. This paper presents the data collected with magnetic, GPR and Automatic Resistivity Profiler (ARP) surveys with the purpose of opening a..

Acute hepatotoxicity of Crotalus durissus terrificus (South American rattlesnake) venom in rats

Venom of the South American rattlesnake, Crotalus durissus terrificus (Cdt), presents myotoxic and neurotoxic outcomes, but reports on its effects on the liver are scarce. This study examined the hepatotoxicity resulting from Cdt venom administration (100, 200 and 300 µg/kg) in male Wistar rats. Animals were studies at 3, 6, 9 and 12 hours after venom injection. The hepatotoxicity was assessed through serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), bilirrubin and also by histopathological evaluation. All the different concentrations of Cdt venom resulted in increased levels of hepatic enzymes, when compared with the control group, except for the 100 µg/kg dose, which presented normal levels at 9 and 12 hours after venom administration. Bilirrubin levels remained unchanged by Cdt venom. Histological analysis revealed endothelial damage, inflammatory cell infiltration, as well as sinusoidal and portal congestion. Based on these observations, we may conclude that Cdt venom causes dose- and time-dependent hepatic damage in rats, characterized by elevated hepatic enzyme levels and histological alterations

ACUTE HEPATOTOXICITY OF Crotalus durissus terrificus (SOUTH AMERICAN RATTLESNAKE) VENOM IN RATS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Venom of the South American rattlesnake, Crotalus durissus terrificus (Cdt), presents myotoxic and neurotoxic outcomes, but reports on its effects on the liver are scarce. This study examined the hepatotoxicity resulting from Cdt venom administration (100, 200 and 300 mu g/kg) in male Wistar rats. Animals were studies at 3, 6, 9 and 12 hours after venom injection. The hepatotoxicity was assessed through serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), bilirrubin and also by histopathological evaluation. All the different concentrations of Cdt venom resulted in increased levels of hepatic enzymes, when compared with the control group, except for the 100 mu g/kg dose, which presented normal levels at 9 and 12 hours after venom administration. Bilirrubin levels remained unchanged by Cdt venom. Histological analysis revealed endothelial damage, inflammatory cell infiltration, as well as sinusoidal and portal congestion. Based on these observations, we may conclude that Cdt venom causes dose- and time-dependent hepatic damage in rats, characterized by elevated hepatic enzyme levels and histological alterations.1516178Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FVE/UNIVAPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Spoken word recognition of novel words, either produced or only heard during learning

This document is the Accepted Manuscript Version of the following article: Tania S. Zamuner, Elizabeth Morin-Lessard, Stephanie Strahm, and Michael P. A. Page, 'Soke word recognition of novel words, either produced or only heard during learning', Journal of Memory and Language, Vol. 89, August 2016, pp. 55-67, doi: 10.1016/j.jml.2015.10.003. Under embargo. Embargo end date: 1 December 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Psycholinguistic models of spoken word production differ in how they conceptualize the relationship between lexical, phonological and output representations, making different predictions for the role of production in language acquisition and language processing. This work examines the impact of production on spoken word recognition of newly learned non-words. In Experiment 1, adults were trained on non-words with visual referents; during training, they produced half of the non-words, with the other half being heard-only. Using a visual world paradigm at test, eye tracking results indicated faster recognition of non-words that were produced compared with heard-only during training. In Experiment 2, non-words were correctly pronounced or mispronounced at test. Participants showed a different pattern of recognition for mispronunciation on non-words that were produced compared with heard-only during training. Together these results indicate that production affects the representations of newly learned words.Peer reviewedFinal Accepted Versio

Nanoelectrode ensembles as recognition platform for electrochemical immunosensors

In this study we demonstrate the possibility to prepare highly sensitive nanostructured electrochemical immunosensors by immobilizing biorecognition elements on nanoelectrode ensembles (NEEs) prepared in track-etch polycarbonate membranes. The gold nanodisk electrodes act as electrochemical transducers while the surrounding polycarbonate binds the antibody-based biorecognition layer. The interaction between target protein and antibody is detected by suitable secondary antibodies labelled with a redox enzyme. A redox mediator, added to the sample solution, shuttles electrons from the nanoelectrodes to the biorecognition layer, so generating an electrocatalytic signal. This allows one to fully exploit the highly improved signal-to-background current ratio, typical of NEEs. In particular, the receptor protein HER2was studied as the target analyte. HER2 detection allows the identification of breast cancer that can be treated with the monoclonal antibody trastuzumab. NEEs were functionalized with trastuzumab which interacts specifically with HER2. The biorecognition process was completed by adding a primary antibody and a secondary antibody labelled with horseradish peroxidase. Hydrogen peroxide was added to modulate the label electroactivity; methylene blue was the redox mediator generating voltammetric signals. NEEs functionalized with trastuzumab were tested to detect small amounts of HER2 in diluted cell lysates and tumour lysates