Isabella Zironi

Context is a trigger for relapse to alcohol

The environment in which alcohol consumption occurs may trigger later relapse in alcohol abusers. In this study, we tested whether an alcohol-associated environment would induce alcohol-seeking behavior. Male rats were trained to lever press for oral alcohol reinforcement in a distinctive context. Responding was then extinguished in a context with different olfactory, visual and tactile properties. Placement of the rats back into the original context in which they self-administered alcohol induced, in the absence of alcohol availability, a significant increase in lever press responding on the alcohol lever as compared to extinction levels of responding. The ability of the alcohol context to support alcohol-seeking behavior was maintained over 3 weeks, with no significant diminution. A second group of rats was trained to lever press for sucrose reinforcement; this group also demonstrated context-dependent reinstatement, although the degree of reinstatement decreased over repeated tests, returning to extinction values after 3 weeks. These findings indicate that contextual conditioning has a long-term impact on ethanol-seeking behavior after ethanol withdrawal. This animal model may be useful to study the neural mechanisms underlying relapse induced by ethanol-associated contexts in humans.

Choline acetyltransferase and NADPH-diaphorase localization in the goldfish habenulo-interpeduncular system

The habenular nuclei are the major sources of projections to the interpeduncular nucleus. The habenular neurons of the goldfish are ChAT and NADPH-diaphorase positive. The localization of these two enzymes in the habenulae suggests the involvement of acetylcholine and nitric oxide (the product of NADPH-diaphorase activity in the nervous tissue) in the habenulo-interpeduncular connection. This finding is supported by the presence of ChAT and NADPH-diaphorase activity in the neuropilar area of the interpeduncular nucleus. This activity was depleted 12 days after habenular ablation. The overlap of ChAT and NADPH-diaphorase localization in goldfish habenular neurons is consistent with previous observations on the co-localization of these two enzymes in some brainstem neurons of other vertebrates. It is, however, not identical to the localization of NADPH-diaphorase in the habenulae and in the interpeduncular nucleus of the rat.

Physical and Electrochemical Properties of PEDOT:PSS as a Tool for Controlling Cell Growth

UNLABELLED Conducting polymers are promising materials for tissue engineering applications, since they can both provide a biocompatible scaffold for physical support of living cells, and transmit electrical and mechanical stimuli thanks to their electrical conductivity and reversible doping. In this work, thin films of one of the most promising materials for bioelectronics applications, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) ( PEDOT PSS), are prepared using two different techniques, spin coating and electrochemical polymerization, and their oxidation state is subsequently changed electrochemically with the application of an external bias. The electrochemical properties of these different types of PEDOT PSS are studied through cyclic voltammetry and spectrophotometry to assess the effectiveness of the oxidation process and its stability over time. Their surface physical properties and their dependence on the redox state of PEDOT PSS are investigated using atomic force microscopy (AFM), water contact angle goniometry and sheet resistance measurements. Finally, human glioblastoma multiforme cells (T98G) and primary human dermal fibroblasts (hDF) are cultured on PEDOT PSS films with different oxidation states, finding that the effect of the substrate on the cell growth rate is strongly cell-dependent: T98G growth is enhanced by the reduced samples, while hDF growth is more effective only on the oxidized substrates that show a strong chemical interaction with the cell culture medium.

Telencephalo-Habenulo-Interpeduncular Connections in the Goldfish: A Dil Study

The telencephalo-habenulo-interpeduncular system has been anatomically and neurochemically characterized in mammals. However, little is known about these important forebrain-midbrain connections in non-mammalian vertebrates, although available data suggest that they are evolutionarily relatively conservative. Previous ultrastructural studies in the goldfish confirmed the presence of massive telencephalohabenular and habenulointerpeduncular projections and demonstrated a minor direct telencephalointerpeduncular connection. Here we report the anterograde and retrograde transport of lipophilic fluorescent carbocyanine dye from the interpeduncular nucleus and the habenular nuclei in the fixed goldfish brain. The application of dye into the interpeduncular nucleus resulted in massive labeling of the fasciculus retroflexus and of the habenular neurons. A few scattered neurons were also seen in the dorsal nucleus of area ventralis telencephali. Application of dye into the habenulae resulted in anterograde transport through the medial and lateral olfactory tracts to some cell bodies in the anterior and posterior zone of area ventralis telencephali and in perikarya of the bed nucleus and in the entopeduncular nucleus. These results demonstrate the origin of the direct telencephalointerpeduncular projection in the goldfish and confirm some important homologies with forebrain-midbrain projections in land vertebrates.

Ultrastructural and immunohistochemical study of the telencephalo-habenulo-interpeduncular connections of the goldfish

Surgical ablations of telencephalon or telencephalon plus habenular nuclei (HBN) have been performed for studying anatomical connections of the telencephalo-habenulo-interpeduncular system of the goldfish. The results of the ultrastructural studies confirmed the presence of massive telencephalo-habenular and habenulo-interpeduncular projections and, in addition, demonstrated a minor direct telencephalo-interpeduncular connection. Immunohistochemical localization of substance P in the interpeduncular nucleus (IPN) after telencephalic ablation failed to demonstrate the involvement of this neurotransmitter in the direct telencephalo-interpeduncular projection, while telencephalon plus HBN ablation reduced substance P immunoreactivity in the IPN. The different distribution of degenerating terminals converging on the IPN from the HBN and from the telencephalon suggested a subnuclear organization of this area, as described in mammals.

Early effects comparison of X rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells

A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

Statistical strategies and stochastic predictive models for the MARK-AGE data

MARK-AGE aims at the identification of biomarkers of human aging capable of discriminating between the chronological age and the effective functional status of the organism. To achieve this, given the structure of the collected data, a proper statistical analysis has to be performed, as the structure of the data are non trivial and the number of features under study is near to the number of subjects used, requiring special care to avoid overfitting. Here we described some of the possible strategies suitable for this analysis. We also include a description of the main techniques used, to explain and justify the selected strategies. Among other possibilities, we suggest to model and analyze the data with a three step strategy.

Biophysics-Based Models of LTP/LTD

Synaptic plasticity is the process by which neurons change the efficacy (or the strength) of their connections (synapses). In the connectionist paradigm, synaptic plasticity is a central concept because it is widely accepted that memory and learning are biologically encoded by variations of neuronal connections strength. In a more general sense, activity-dependent synaptic plasticity is assumed to be necessary and sufficient to encode and store memory in specific brain areas. Another feature of synaptic plasticity is the bidirectionality, which is the capability to increase or decrease the synaptic weights, thus encompassing the classical Hebbian paradigm.

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device

Radiation therapy is a useful and standard tumor treatment strategy. Despite recent advances in delivery of ionizing radiation, survival rates for some cancer patients are still low because of recurrence and radioresistance. This is why many novel approaches have been explored to improve radiotherapy outcome. Some strategies are focused on enhancement of accuracy in ionizing radiation delivery and on the generation of greater radiation beams, for example with a higher dose rate. In the present study we proposed an in vitro research of the biological effects of very high dose rate beam on SK-Mel28 and A375, two radioresistant human melanoma cell lines. The beam was delivered by a pulsed plasma device, a “Mather type” Plasma Focus for medical applications. We hypothesized that this pulsed X-rays generator is significantly more effective to impair melanoma cells survival compared to conventional X-ray tube. Very high dose rate treatments were able to reduce clonogenic efficiency of SK-Mel28 and A375 more than the X-ray tube and to induce a greater, less easy-to-repair DNA double-strand breaks. Very little is known about biological consequences of such dose rate. Our characterization is preliminary but is the first step toward future clinical considerations.

Network integration of multi-tumour omics data suggests novel targeting strategies

We characterize different tumour types in search for multi-tumour drug targets, in particular aiming for drug repurposing and novel drug combinations. Starting from 11 tumour types from The Cancer Genome Atlas, we obtain three clusters based on transcriptomic correlation profiles. A network-based analysis, integrating gene expression profiles and protein interactions of cancer-related genes, allows us to define three cluster-specific signatures, with genes belonging to NF-κB signaling, chromosomal instability, ubiquitin-proteasome system, DNA metabolism, and apoptosis biological processes. These signatures have been characterized by different approaches based on mutational, pharmacological and clinical evidences, demonstrating the validity of our selection. Moreover, we define new pharmacological strategies validated by in vitro experiments that show inhibition of cell growth in two tumour cell lines, with significant synergistic effect. Our study thus provides a list of genes and pathways that could possibly be used, singularly or in combination, for the design of novel treatment strategies.Tumours of different tissues can show similarities in genomic alterations. Here, the authors combine tumour transcriptome and protein interaction data in a network-based analysis of 11 tumours types, and identify clusters of tumours with specific signatures for multi-tumour drug targeting and survival prognosis.