Pharmacophore aided hit identification, structural optimization and biological evaluation of benzothiazole derivatives as new potent and selective non-steroidal inhibitors of 17beta-hydroxysteroid dehydrogenase type 1

17beta-Hydroxysteroid dehydrogenase 1 (17beta-HSD1) catalyzes the conversion of the weakly active estrone (E1) to the highly active estradiol (E2). Recently, 17β-HSD1 came into the focus of interest as a novel therapeutic target for the treatment of estrogen dependent diseases like breast cancer (BC) and endometriosis. Two new classes of non-steroidal 17beta-HSD1 inhibitors were designed and synthesized as potential therapeutics. The search started from the pharmacophore screening of in house library (molecules with MW < 350). The virtual hits were experimentally validated, and, finally, a new core structure ([5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-2-yl](3-hydroxyphenyl)methanone) with a moderate inhibitory activity for 17beta-HSD1 was identified. Rigidification of the flexible hydroxy ethyl chain led to a benzothiazole derivative which already showed high inhibitory potency towards the target enzyme. Further structural modifications - OH substitution pattern, addition and variation of small substituents on different position of the phenyl moiety – via the synthesis of 70 new compounds led the discovery of two new classes of potent 17beta-HSD1 inhibitors with IC50 values in the low nanomolar range. In order not to counteract the therapeutic efficacy of 17β-HSD1 inhibitors it is important that the compounds are selective towards 17β-HSD2 since this enzyme catalyses the reverse reaction (oxidation of E2 to E1) and furthermore to avoid intrinsic estrogenic and systemic effects, the inhibitors should not show affinity to the estrogen receptors alpha and beta. Besides an excellent selectivity over 17beta-HSD2 and the estrogen receptors (ERs) alpha and beta, the most promising compounds of this study showed good cell permeability (T47-D), fair metabolic stability in human liver microsomes and moderate hepatic CYP inhibition. High inhibitory potency and selectivity was also found towards marmoset monkey 17beta-HSD1 and 17beta-HSD2 indicating that these compounds are suitable for in vivo evaluation in this animal endometriosis model. In conclusion, the present thesis provides an extensive structure-activity study regarding 17beta-HSD1 inhibition which might be useful for the developement of a clinically applicable therapeutic for the treatment of estrogen-dependent diseases.17ß-Hydroxysteroid Dehydrogenase 1 (17ß-HSD1) katalysiert die Biosynthese vom schwach wirksamen Estron (E1) zum hoch potenten Estradiol (E2). In den letzten Jahren ist 17ß-HSD1 als neuartiges therapeutisches Target zur Behandlung von Estrogen-abhängigen Krankheiten, wie Burstkrebs und Endometriose in den Fokus gekommen. In dieser Arbeit wurden zwei neue Klassen nicht-steroidaler 17ß-HSD1 Hemmstoffe designet, synthetisiert und biochemisch evaluiert. Zum Einstieg wurde basierend auf ko-krystallisierte steroidale Inhibitoren ein Pharmakophor-Modell erstellt. Dieses wurde dann zum Screening einer in In-house Substanzbibliothek (MW < 350) genutzt. Die besten virtuellen Hits wurden experimentell validiert und ([5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-2-yl](3-hydroxyphenyl)methanone) wurde als neue Core-Struktur mit moderater Hemmwirkung identifiziert. Rigidisierung der flexiblen Hydroxyethyl-Seitenkette führte zur Synthese eines Benzylimidazol-Derivates, welches eine beachtliche Steigerung der Aktivität zeigte. Weitere strukturelle Variationen, wie z.B. Veränderung der OH-Position, Einfügen bzw. Ersetzen neuer Substituenten an unterschiedlichen Positionen des Phenyl-Ringes, führten zur Synthese von mehr als siebzig Verbindungen, die in zwei Klassen potenter HSD1-Hemmstoffe unterteilt werden können. IC50-Werte im niedrigen nanomolaren Bereich wurden erzielt. Um der therapeutischen Effizienz dieser 17ß-HSD1 Inhibitoren nicht entgegenzuwirken ist es wichtig, dass diese Verbindungen selektiv gegen 17ß-HSD2 sind, da dieses Enzym die Rückreaktion (Umwandlung von E2 wird in E1) katalysiert. Des weiteren sollen potentielle 17ß-HSD1 Hemmstoffe auch keine Affinität zu den Estrogen-Rezeptoren a und ß aufweisen, um systemische Wirkungen zu vermeiden. Abgesehen von einer exzellenten Selektivität gegen 17ß-HSD2 sowie beider Estrogenrezeptoren zeigten die vielversprechendsten der synthetisierten Substanzen auch eine gute Permeabilität in T47-D Zellen, eine akzeptable metabolische Stabilität in humanen Lebermikrosomen und nur eine moderate Hemmung einiger hepatischer CYP Enzyme. Beide neuen Substanzklassen wiesen eine hohe Hemmung von 17ß-HSD1 sowie Selektivität gegen 17ß-HSD2 von Callithrix jacchus auf, was sie für eine in vivo Testung an diesem Endometriose-Model in Frage kommen läßt. Zusammenfassend ist festzustellen, daß in dieser Doktorarbeit eine ausführliche Struktur- Wirkungs-Studie von 17ß-HSD1 Inhibitoren beschrieben ist, die eine wichtige Rolle für die weitere Entwicklung von Therapeutika zur Behandlung von Estrogen-abhängigen Erkrankungen spielen kann

Tunability of exchange bias in Ni@NiO core-shell nanoparticles obtained by sequential layer deposition

Films of magnetic Ni@NiO core-shell nanoparticles (NPs, core diameter d\ua0 45\ua012 nm, nominal shell thickness variable between 0 and 6.5 nm) obtained with sequential layer deposition were investigated, to gain insight into the relationships between shell thickness/morphology, core-shell interface, and magnetic properties. Different values of NiO shell thickness ts could be obtained while keeping the Ni core size fixed, at variance with conventional oxidation procedures where the oxide shell is grown at the expense of the core. Chemical composition, morphology of the as-produced samples and structural features of the Ni/NiO interface were investigated with x-ray photoelectron spectroscopy and microscopy (scanning electron microscopy, transmission electron microscopy) techniques, and related with results from magnetic measurements obtained with a superconducting quantum interference device. The effect of the shell thickness on the magnetic properties could be studied. The exchange bias (EB) field Hbias is small and almost constant for ts up to 1.6 nm; then it rapidly grows, with no sign of saturation. This behavior is clearly related to the morphology of the top NiO layer, and is mostly due to the thickness dependence of the NiO anisotropy constant. The ability to tune the EB effect by varying the thickness of the last NiO layer represents a step towards the rational design and synthesis of core-shell NPs with desired magnetic properties

Imaging the invasion of rice roots by the bakanae agent Fusarium fujikuroi using a GFP-tagged isolate

Altres ajuts: Generalitat de Catalunya/CERCA Programme, AGER Foundation (Grant 2010-2369)Fusarium fujikuroi (teleomorph Gibberella fujikuroi) is the main seed-borne pathogen of rice, the causal agent of bakanae, a disease that in the last years has become of increasing economical concern in many Italian rice growing areas. A virulent F. fujikuroi isolate was tagged with the green fluorescent protein (gfp) gene using Agrobacterium tumefaciens mediated transformation, and the virulence of the GFP isolate has been confirmed. Little is known about the early interaction of the pathogen with its host, in this work fungal development during the F. fujikuroi/root interaction was analysed by Laser Scanning Confocal Microscopy (LSCM), by using the GFP isolate obtained. The infection of rice roots was investigated from 48 h to 8 days post-inoculation both in resistant and susceptible cultivars. Roots of resistant genotype seem to trigger a hypersensitive response at the infection site and LSCM analysis of root sections allowed the visualization of fungal growth within host tissues. Fungal growth occurred both in the resistant and the susceptible cultivar, even if it was less abundant in the resistant one. Expression analysis of Chitinase1, a gene involved in fungal pathogenesis, was investigated by qPCR on the F. fujikuroi infected rice roots. Chitinase1 expression increased greatly upon infection in the resistant cultivar Selenio

Steering the magnetic properties of Ni/NiO/CoO core-shell nanoparticle films: The role of core-shell interface versus interparticle interactions

Supported core-shell Ni/NiO/CoO nanoparticle (NP) films were obtained by deposition of preformed and mass-selected Ni NPs on a buffer layer of CoO, followed by a top CoO layer. The resulting NPs have core/shell morphology, with a McKay icosahedral Ni core and a partially crystalline CoO shell. X-ray photoelectron spectroscopy evidenced the presence of a thin NiO layer, which was shown to be between the Ni core and the CoO shell by elemental TEM mapping. CoO and NiO shells with different thickness values were obtained, allowing us to investigate the evolution of the magnetic properties of the NP assemblies as a function of the oxide shell thickness. Both exchange-coupling and magnetostatic interactions significantly contribute to the magnetic behavior of Ni/NiO/CoO NP films. After the Ni/NiO/CoO NPs are cooled in a weak magnetic field, they have blocking temperature higher than room temperature because of strong magnetostatic interactions, which support the formation of a spin-glass-like state below similar to 250 K. Exchange coupling dominates the magnetic behavior after the NPs are cooled in a strong magnetic field. The exchange bias (EB) is in the 0.17-2.35 kOe range and strongly depends on the CoO thickness (0.4-2.7 nm), showing the onset of the EB at the few-nanometer scale. The switching field distribution showed that the EB opposes the magnetization reversal from the direction along the cooling field but it does not significantly ease the opposite process. The EB depends on t(CoO) only for t(NiO) <= 0.5 nm, but when NiO is 0.7 nm thick it strongly interacts with CoO and a large increase of the EB and coercivity is observed

double blind placebo controlled randomized trial on low dose azithromycin prophylaxis in patients with primary antibody deficiencies

Background Lacking protective antibodies, patients with primary antibody deficiencies (PADs) experience frequent respiratory tract infections, leading to chronic pulmonary damage. Macrolide prophylaxis has proved effective in patients with chronic respiratory diseases. Objective We aimed to test the efficacy and safety of orally administered low-dose azithromycin prophylaxis in patients with PADs. Methods We designed a 3-year, double-blind, placebo-controlled, randomized clinical trial to test whether oral azithromycin (250 mg administered once daily 3 times a week for 2 years) would reduce respiratory exacerbations in patients with PADs and chronic infection–related pulmonary diseases. The primary end point was the number of annual respiratory exacerbations. Secondary end points included time to first exacerbation, additional antibiotic courses, number of hospitalizations, and safety. Results Eighty-nine patients received azithromycin (n = 44) or placebo (n = 45). The number of exacerbations was 3.6 (95% CI, 2.5-4.7) per patient-year in the azithromycin arm and 5.2 (95% CI, 4.1-6.4) per patient-year in the placebo arm (P = .02). In the azithromycin group the hazard risk for having an acute exacerbation was 0.5 (95% CI, 0.3-0.9; P = .03), and the hazard risk for hospitalization was 0.5 (95% CI, 0.2-1.1; P = .04). The rate of additional antibiotic treatment per patient-year was 2.3 (95% CI, 2.1-3.4) in the intervention group and 3.6 (95% CI, 2.9-4.3) in the placebo group (P = .004). Haemophilus influenzae and Streptococcus pneumoniae were the prevalent isolates, and they were not susceptible to macrolides in 25% of patients of both arms. Azithromycin's safety profile was comparable with that of placebo. Conclusion The study reached the main outcome centered on the reduction of exacerbation episodes per patient-year, with a consequent reduction in additional courses of antibiotics and risk of hospitalization

On the Evolution of a Sub-C Class Flare: A Showcase for the Capabilities of the Revamped Catania Solar Telescope

Solar flares are occasionally responsible for severe space-weather events, which can affect space-borne and ground-based infrastructures, endangering anthropic technological activities and even human health and safety. Thus, an essential activity in the framework of space-weather monitoring is devoted to the observation of the activity level on the Sun. In this context, the acquisition system of the Catania Solar Telescope has been recently upgraded in order to improve its contribution to the European Space Agency (ESA) - Space Weather Service Network through the ESA Portal, which represents the main asset for space weather in Europe. Here, we describe the hardware and software upgrades of the Catania Solar Telescope and the main data products provided by this facility, which include full-disk images of the photosphere and chromosphere, together with a detailed characterization of sunspot groups. As a showcase of the observational capabilities of the revamped Catania Solar Telescope, we report the analysis of a B5.4 class flare that occurred on 7 December 2020, simultaneously observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory satellites...