65 research outputs found
Novel bioactive metabolites from marine sources: isolation, structural elucidation and synthetic studies.
Among marine organism, Porifera have proven to be a rich source of new metabolites. Sponge are sessile organisms, therefore lacking any physical defence against predators. To make up to this lack, they produce species-specific molecules, known as secondary metabolites, which may play a key role in interspecific competition, defense against predators and reproduction processes. Secondary metabolites of marine origins are interesting molecules, often characterised by complex and unusual structures, which have shown to have a broad spectrum of pharmacological activities, such as anti-inflammatory, antiviral, antibiotic and anticancer. These compounds are hence considered promising lead compounds in drug discovery. Recently, many marine natural products have been approved, and others are in clinical trials. Due to the small amount isolated from the marine source, the evaluation of the biological activity of these compounds is often limited. Many alternatives have been considered to solve this issue. The total or semi-synthesis of these compound represents a valide alternative to provide greater amounts of the metabolites of interest, allowing to gain a better insight in their biological activity. Currently, the number of synthetic or semi-synthetic drugs is indeed strongly increasing.
This research field forms the backdrop to my PhD work, aimed to the identification and structural elucidation of new bioactive marine natural products and to the synthesis of analogues with improved biological activities. The main topic of my reseach activity was the total synthesis of hybrid peptide/polyketide compounds of marine origins. Simultaneously, I was involved in the analysis of the chemical content of the Caribbean sponge Smenospongia conulosa and the Mediterranean sponge Geodia cydonium.
The analysis of the lipofilic extract of the Caribbean sponge S. aurea led to the isolation, in 2013, of two hybrid peptide/polyketide compounds: smenamide A and B. Although both compounds possess a cytotoxic activity at nanomolar levels, smenamide A resulted more active blocking the cell proliferation through a pro-aapoptotic mechanism. Therefore the total synthesis of smenamide A and its analogues was undertaken in order to provide greater amount of the compounds needed to confirm the structure of the compound, determine the absolute configuration at C-16, that remained undetermined until the end of the synthetic project, and to further investigate the cytotoxic activity. The total synthesis resulted in the preparation of 16-epi- and ent-smenamide A, two synthetic analogues of smenamide A.
In order to investigate the role of the structural determining-features of smenamides family, eight shorter-chain analogues of the synthetic 16-epi-smenamide A have been designed and prepared. The evaluation of the antiproliferative activity of 16-epi-smenamide A, together with its analogues, is now in progress.
On the other hand, the analysis of the organic extracts of the Caribbean sponge Smenospongia conulosa and the Mediterranean sponge Geodia cydonium led to the identification of two new hybrid peptide/polyketide compounds, conulothiazole A and B, and an active fraction, respectively.
The evaluation of the biological activity of conulothiazoles could not be carried out because of the low amount isolated from the marine source.
As for G. cydonium active fraction, it showed an antiproliferative activity on three humar cancer breast cell lines (MCF-7, MDA-MB-231 and MDA-MB-468). The use of LC-HRMS, LC-HRMS/MS coupled with a bioinformatic techniques, e.g. Molecular Networking, as a novel dereplication strategy allowed to identify most of the metabolites contained in this fraction. In addition, the evaluation of the metabolomic profiling and the cytokine levels of the three cancer cell lines after treatment with the active fraction showed that the latter participates in the modulation of several metabolites in pro- or anti-tumor processes. Further studies are necessary in order to understand the mechanism of action of each compound contained in this fraction, as well as the evaluation of the possible synergistic effect of a pool of compounds
Fast Detection of Two Smenamide Family Members Using Molecular Networking.
Caribbean sponges of the genus Smenospongia are a prolific source of chlorinated secondary metabolites. The use of molecular networking as a powerful dereplication tool revealed in the metabolome of S. aurea two new members of the smenamide family, namely smenamide F (1) and G (2). The structure of smenamide F (1) and G (2) was determined by spectroscopic analysis (NMR, MS, ECD). The relative and the absolute configuration at C-13, C-15, and C-16 was determined on the basis of the conformational rigidity of a 1,3-disubstituted alkyl chain system (i.e., the C-12/C-18 segment of compound (1). Smenamide F (1) and G (2) were shown to exert a selective moderate antiproliferative activity against cancer cell lines MCF-7 and MDA-MB-231, while being inactive against MG-63
Insights into disability and psycho-social care of patients with inflammatory bowel disease
In recent years, the concept of disability has increasingly garnered attention as a crucial long-term target of inflammatory bowel disease (IBD) management. The treatment paradigm has changed dramatically from full control of the disease (clinical and endoscopic remission) toward physical and emotional well-being with the goal of preventing disability and normalizing quality of life. However, in certain cases, despite achieving good disease control, patients may still experience symptoms associated with disability, and reduced emotional wellness. These symptoms can significantly impact various biopsychosocial factors, including interpersonal relationships, educational or work-related activities, body image, and sexual functioning. Nevertheless, they often remain overlooked in the context of IBD care. In this narrative review, we aim to shed light on the burden of certain disability-related symptoms such as bowel urgency, sexual dysfunction, impaired fertility and fatigue, emphasizing the importance of acknowledging and validating them in a clinical setting. There is a demanding need for comprehensive care for IBD patients, with IBD clinicians being mindful of the psychosocial challenges faced by their patients. Providing timely and appropriate management of these challenges alongside IBD treatment is key to achieving holistic remission and enhancing the overall quality of life while reducing disability
Early Hemorrhagic Transformation of Brain Infarction: Rate, Predictive Factors, and Influence on Clinical Outcome
Background and Purpose—
Early hemorrhagic transformation (HT) is a complication of ischemic stroke but its effect on patient outcome is unclear. The aims of this study were to assess: (1) the rate of early HT in patients admitted for ischemic stroke, (2) the correlation between early HT and functional outcome at 3 months, and (3) the risk factors for early HT.
Methods—
Consecutive patients with ischemic stroke were included in this prospective study in 4 study centers. Early HT was assessed by CT examination performed at day 5±2 after stroke onset. Study outcomes were 3-month mortality or disability. Disability was assessed using a modified Rankin score (≥3 indicating disabling stroke) by neurologists unaware of the occurrence of HT in the individual cases. Outcomes in patients with and without early HT were compared by χ
2
test. Multiple logistic regression analysis was used to identify predictors for HT.
Results—
Among 1125 consecutive patients (median age 76.00 years), 98 (8.7%) had HT, 62 (5.5%) had hemorrhagic infarction, and 36 (3.2%) parenchymal hematoma. At 3 months, 455 patients (40.7%) were disabled or died. Death or disability was seen in 33 patients with parenchymal hematoma (91.7%), in 35 patients with hemorrhagic infarction (57.4%) as compared with 387 of the 1021 patients without HT (37.9%). At logistic regression analysis, parenchymal hematoma, but not hemorrhagic infarction, was independently associated with an increased risk for death or disability (OR 15.29; 95% CI 2.35 to 99.35). At logistic regression analysis, parenchymal hematoma was predicted by large lesions (OR 12.20, 95% CI 5.58 to 26.67), stroke attributable to cardioembolism (OR 5.25; 95% CI 2.27 to 12.14) or to other causes (OR 6.77; 95% CI 1.75 to 26.18), high levels of blood glucose (OR 1.01; 95% CI 1.00 to 1.01), and thrombolytic treatment (OR 3.54, 95% CI 1.04 to 11.95).
Conclusions—
Early HT occurs in about 9% of patients. Parenchymal hematoma, seen in about 3% of patients, is associated with an adverse outcome. Parenchymal hematoma was predicted by large lesions attributable to cardioembolism or other causes, high blood glucose, and treatment with thrombolysis
Fatty Acid Substitutions Modulate the Cytotoxicity of Puwainaphycins/Minutissamides Isolated from the Baltic Sea Cyanobacterium Nodularia harveyana UHCC-0300
Puwainaphycins (PUW) and minutissamides (MIN) are structurally homologous cyclic lipopeptides that exhibit high structural variability and possess antifungal and cytotoxic activities. While only a minor variation can be found in the amino acid composition of the peptide cycle, the fatty acid (FA) moiety varies largely. The effect of FA functionalization on the bioactivity of PUW/MIN chemical variants is poorly understood. A rapid and selective liquid chromatography-mass spectrometry-based method led us to identify 13 PUW/MIN (1-13) chemical variants from the benthic cyanobacterium Nodularia harveyana strain UHCC-0300 from the Baltic Sea. Five new variants identified were designated as PUW H (1), PUW I (2), PUW J (4), PUW K (10), and PUW L (13) and varied slightly in the peptidic core composition, but a larger variation was observed in the oxo-, chloro-, and hydroxy-substitutions on the FA moiety. To address the effect of FA substitution on the cytotoxic effect, the major variants (3 and 5-11) together with four other PUW/MIN variants (14-17) previously isolated were included in the study. The data obtained showed that hydroxylation of the FA moiety abolishes the cytotoxicity or significantly reduces it when compared with the oxo-substituted C-18-FA (compounds 5-8). The oxo-substitution had only a minor effect on the cytotoxicity of the compound when compared to variants bearing no substitution. The activity of PUW/ MIN variants with chlorinated FA moieties varied depending on the position of the chlorine atom on the FA chain. This study also shows that variation in the amino acids distant from the FA moiety (position 4-8 of the peptide cycle) does not play an important role in determining the cytotoxicity of the compound. These findings confirmed that the lipophilicity of FA is essential to maintain the cytotoxicity of PUW/MIN lipopeptides. Further, a 63 kb puwainaphycin biosynthetic gene cluster from a draft genome of the N. harveyana strain UHCC-0300 was identified. This pathway encoded two specific lipoinitiation mechanisms as well as enzymes needed for the modification of the FA moiety. Examination on biosynthetic gene clusters and the structural variability of the produced PUW/MIN suggested different mechanisms of fatty-aryl-AMP ligase cooperation with accessory enzymes leading to a new set of PUW/MIN variants bearing differently substituted FA.Peer reviewe
Quality of life changes over time and predictors in a large head and neck patients' cohort: secondary analysis from an Italian multi-center longitudinal, prospective, observational study-a study of the Italian Association of Radiotherapy and Clinical Oncology (AIRO) head and neck working group
Purpose: The present study examined the longitudinal trajectories, through hierarchical modeling, of quality of life among patients with head and neck cancer, specifically symptoms burden, during radiotherapy, and in the follow-up period (1, 3, 6, and 12 months after completion of radiotherapy), through the M.D. Anderson Symptom Inventory Head and Neck questionnaire, formed by three factors. Furthermore, analyses were conducted controlling for socio-demographic as well as clinical characteristics. Methods: Multi-level mixed-effects linear regression was used to estimate the association between quality of life and time, age, gender, household, educational level, employment status, ECOG performance status, human papilloma virus (HPV) status, surgery, chemotherapy, alcohol intake, and smoking. Results: Among the 166 participants, time resulted to be a predictor of all the three questionnaire factors, namely, general and specific related symptoms and interference with daily life. Moreover, regarding symptom interference with daily activities factor, HPV-positive status played a significant role. Considering only HPV-negative patients, only time predicted patients' quality of life. Differently, among HPV-positive patients, other variables, such as gender, educational level, alcohol use, surgery, age at diagnosis, employment status, and ECOG status, resulted significant. Conclusion: It was evident that quality of life of patients with head and neck cancer declined during RT, whereas it slowly improved after ending treatment. Our results clarified the role of some socio-demographic and clinical variables, for instance, HPV, which would allow to develop treatments tailored to each patient
GEN-O-MA project: an Italian network studying clinical course and pathogenic pathways of moyamoya disease—study protocol and preliminary results
Background: GENetics of mOyaMoyA (GEN-O-MA) project is a multicenter observational study implemented in Italy aimed at creating a network of centers involved in moyamoya angiopathy (MA) care and research and at collecting a large series and bio-repository of MA patients, finally aimed at describing the disease phenotype and clinical course as well as at identifying biological or cellular markers for disease progression. The present paper resumes the most important study methodological issues and preliminary results. Methods: Nineteen centers are participating to the study. Patients with both bilateral and unilateral radiologically defined MA are included in the study. For each patient, detailed demographic and clinical as well as neuroimaging data are being collected. When available, biological samples (blood, DNA, CSF, middle cerebral artery samples) are being also collected for biological and cellular studies. Results: Ninety-eight patients (age of onset mean ± SD 35.5 ± 19.6 years; 68.4% females) have been collected so far. 65.3% of patients presented ischemic (50%) and haemorrhagic (15.3%) stroke. A higher female predominance concomitantly with a similar age of onset and clinical features to what was reported in previous studies on Western patients has been confirmed. Conclusion: An accurate and detailed clinical and neuroimaging classification represents the best strategy to provide the characterization of the disease phenotype and clinical course. The collection of a large number of biological samples will permit the identification of biological markers and genetic factors associated with the disease susceptibility in Italy
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
Standalone vertex finding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011
Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions
Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV
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