Design, synthesis and study of molecules for graphene functionalization

La compréhension du contrôle de la fonctionnalisation chimique du graphène est un prérequis essentiel pour pouvoir exploiter toutes les propriétés de ce matériau. L'objectif central de ces travaux de thèse est de recourir à l'auto-assemblage pour obtenir une organisation spatiale précise de groupements fonctionnels "actifs" avec une surface de graphène. En particulier, ces fonctionnalités chimiques doivent interagir avec le graphène soit par interaction non-covalente forte, amenant à un dopage local, ou par réaction activée sous pointe STM (Microscope à effet tunnel), amenant à la formation d'une liaison covalente. Dans une première partie, nous avons synthétisé un dérivé de tetrathiafulvalene et un hexaphenanthrocoronène, choisis pour leurs caractères donneurs d'électrons pour des surfaces de graphène épitaxié sur carbure de silicium. Dans la deuxième partie, nous présentons la synthèse de différents dérivés de polyphényles ou poly-phényléthynyles, conçus pour une réactivité avec le graphène de type radicalaire (dans le cas de précurseurs bromés) ou par réaction de Diels-Alder (par des fonctions maléimide ou anthracène). Des études STM et Raman ont permis de démontrer les propriétés d'auto-assemblage et la réactivité de certains de ces dérivés.Getting a deeper insight into the controlled chemical functionalization of graphene represents a pre-requisite essential for fully exploiting all the promising properties of this material. The central objective of this thesis is to resort to self-assembly in order to achieve a precise spatial organization of "active" functional groups on the graphene surface. In particular, these functionalities are meant to interact with graphene either by strong non-covalent interactions, inducing a local doping, or by a Scanning Tunnelling Microscope (STM)-tip activated chemical reaction, driving to the formation of a covalent bond. In a first part, we synthesized a tetrathiafulvalene and a hexaphenanthrocoronene derivative, chosen because of their potential electron donor capabilities towards epitaxial graphene grown on silicon carbide. In a second part, we synthesized a series of poly-phenyl or poly-phenyl-ethynyl derivatives, designed to present a radicalar (i.e. brominated precursors) or Diels-Alder (i.e. maleimide or anthracene functional groups) reactivity with graphene, by STM activation. STM and Raman studies have allowed assessing the self-assembling behaviour and reactivity of some of the synthetized derivatives

Early aphasia rehabilitation is associated with functional reactivation of the left inferior frontal gyrus a pilot study

Background and Purpose—Early poststroke aphasia rehabilitation effects and their functional MRI (fMRI) correlates were investigated in a pilot, controlled longitudinal study. Methods—Twelve patients with mild/moderate aphasia (8 Broca, 3 anomic, and 1 Wernicke) were randomly assigned to daily language rehabilitation for 2 weeks (starting 2.2 [mean] days poststroke) or no rehabilitation. The Aachen Aphasia Test and fMRI recorded during an auditory comprehension task were performed at 3 time intervals: mean 2.2 (T1), 16.2 (T2), and 190 (T3) days poststroke. Results—Groups did not differ in terms of age, education, aphasia severity, lesions volume, baseline fMRI activations, and in task performance during fMRI across examinations. Rehabilitated patients significantly improved in naming and written language tasks (P<0.05) compared with no rehabilitation group both at T2 and T3. Functional activity at T1 was reduced in language-related cortical areas (right and left inferior frontal gyrus and middle temporal gyrus, right inferior parietal lobule and superior temporal gyrus) in patients compared with controls. T2 and T3 follow-ups revealed a cortical activation increase, with significantly greater activation in the left hemisphere areas in rehabilitated patients at T2 and T3, and a time×treatment effect at T2 in the left inferior Broca area after rehabilitation. Left inferior frontal gyrus activation at T2 significantly correlated with naming improvement. Conclusions—Early poststroke aphasia treatment is useful, has durable effects, and may lead to early enhanced recruitment of brain areas, particularly the left inferior frontal gyrus, which persists in the chronic phase

TRPV1 channels are critical brain inflammation detectors and neuropathic pain biomarkers in mice

The capsaicin receptor TRPV1 has been widely characterized in the sensory system as a key component of pain and inflammation. A large amount of evidence shows that TRPV1 is also functional in the brain although its role is still debated. Here we report that TRPV1 is highly expressed in microglial cells rather than neurons of the anterior cingulate cortex and other brain areas. We found that stimulation of microglial TRPV1 controls cortical microglia activation per se and indirectly enhances glutamatergic transmission in neurons by promoting extracellular microglial microvesicles shedding. Conversely, in the cortex of mice suffering from neuropathic pain, TRPV1 is also present in neurons affecting their intrinsic electrical properties and synaptic strength. Altogether, these findings identify brain TRPV1 as potential detector of harmful stimuli and a key player of microglia to neuron communication

Statins and histone deacetylase inhibitors affect lamin A/C - histone deacetylase 2 interaction in human cells

We recently identified lamin A/C as a docking molecule for human histone deacetylase 2 (HDAC2) and showed involvement of HDAC2-lamin NC complexes in the DNA damage response. We further showed that lamin NC-HDAC2 interaction is altered in Hutchinson-Gilford Progeria syndrome and other progeroid laminopathies. Here, we show that both inhibitors of lamin A maturation and small molecules inhibiting HDAC activity affect lamin NC interaction with HDAC2. While statins, which inhibit prelamin A processing, reduce protein interaction, HDAC inhibitors strengthen protein binding. Moreover, treatment with HDAC inhibitors restored the enfeebled lamin NC-HDAC2 interaction observed in HGPS cells. Based on these results, we propose that prelamin A levels as well as HDAC2 activation status might influence the extent of HDAC2 recruitment to the lamin A/C-containing platform and contribute to modulate HDAC2 activity. Our study links prelamin A processing to HDAC2 regulation and provides new insights into the effect of statins and histone deacetylase inhibitors on lamin NC functionality in normal and progeroid cells

Electrocardiographic changes in normal and abnormal canine pregnancy

The aim of this study was to describe the canine electrocardiographic changes in the course of normal and abnormal pregnancy. Twenty-three Brucellosis-negative pregnant bitches were retrospectively classified as normal (n=12) or abnormal (n=11). A control group of non-pregnant dioestrous bitches (n=10) was also included. Normal pregnant females delivered healthy puppies at term while abnormal animals interrupted their pregnancy between days 52-60 (from estimated luteinizing hormone peak) or presented perinatal litter death higher than 60%. All the bitches were electrocardiographically evaluated every 10days from day 0 to day 65 of the oestrous cycle, to parturition or abortion. Percentage heart rate change increased 31.3% from day 40 to 60 in normal gestation while it decreased -1.8% in dioestrous bitches, although it did not change in the abnormal group (p<0.01). In the abnormal pregnant group but not in the others, percentage QRSa change fell to -34% on day 60 (p<0.01). At the same time point, percentage QRSd change was 6.2% vs -4.9% in normal gestations and dioestrous animals, respectively (p<0.05). Corrected QT interval augmented from day 40 onwards up to 9.9% and 4.3% in the normal pregnant and dioestrous groups, respectively, while it remained unchanged in abnormal gestations (p<0.05). It is concluded that during normal canine pregnancy, some electrocardiographic parameters begin changing from day 40 onwards, and that pathological gestations differ from normality from day 30. The use of electrocardiography in canine obstetrics might contribute to identify abnormal outcomes before they become clinically evident.Fil: Blanco, Paula Graciela. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Batista, Pablo Rodrigo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Re, N. E.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Mattioli, Guillermo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; ArgentinaFil: Arias, Daniel Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Gobello, María Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Statins and Histone Deacetylase Inhibitors Affect Lamin A/C – Histone Deacetylase 2 Interaction in Human Cells

We recently identified lamin A/C as a docking molecule for human histone deacetylase 2 (HDAC2) and showed involvement of HDAC2-lamin A/C complexes in the DNA damage response. We further showed that lamin A/C-HDAC2 interaction is altered in Hutchinson-Gilford Progeria syndrome and other progeroid laminopathies. Here, we show that both inhibitors of lamin A maturation and small molecules inhibiting HDAC activity affect lamin A/C interaction with HDAC2. While statins, which inhibit prelamin A processing, reduce protein interaction, HDAC inhibitors strengthen protein binding. Moreover, treatment with HDAC inhibitors restored the enfeebled lamin A/C-HDAC2 interaction observed in HGPS cells. Based on these results, we propose that prelamin A levels as well as HDAC2 activation status might influence the extent of HDAC2 recruitment to the lamin A/C-containing platform and contribute to modulate HDAC2 activity. Our study links prelamin A processing to HDAC2 regulation and provides new insights into the effect of statins and histone deacetylase inhibitors on lamin A/C functionality in normal and progeroid cells

Prognostic immune markers identifying patients with severe COVID-19 who respond to tocilizumab

Introduction: A growing number of evidences suggest that the combination of hyperinflammation, dysregulated T and B cell response and cytokine storm play a major role in the immunopathogenesis of severe COVID-19. IL-6 is one of the main pro-inflammatory cytokines and its levels are increased during SARS-CoV-2 infection. Several observational and randomized studies demonstrated that tocilizumab, an IL-6R blocker, improves survival in critically ill patients both in infectious disease and intensive care units. However, despite transforming the treatment options for COVID-19, IL-6R inhibition is still ineffective in a fraction of patients. Methods: In the present study, we investigated the impact of two doses of tocilizumab in patients with severe COVID-19 who responded or not to the treatment by analyzing a panel of cytokines, chemokines and other soluble factors, along with the composition of peripheral immune cells, paying a particular attention to T and B lymphocytes. Results: We observed that, in comparison with non-responders, those who responded to tocilizumab had different levels of several cytokines and different T and B cells proportions before starting therapy. Moreover, in these patients, tocilizumab was further able to modify the landscape of the aforementioned soluble molecules and cellular markers. Conclusions: We found that tocilizumab has pleiotropic effects and that clinical response to this drug remain heterogenous. Our data suggest that it is possible to identify patients who will respond to treatment and that the administration of tocilizumab is able to restore the immune balance through the re-establishment of different cell populations affected by SARS-COV-2 infection, highlighting the importance of temporal examination of the pathological features from the diagnosis

dysferlin in a hyperckaemic patient with caveolin 3 mutation and in c2c12 cells after p38 map kinase inhibition

Dysferlin is a plasma membrane protein of skeletal muscle whose deficiency causes Miyoshi myopathy, limb girdle muscular dystrophy 2B and distal anterior compartment myopathy. Recent studies have reported that dysferlin is implicated in membrane repair mechanism and coimmunoprecipitates with caveolin 3 in human skeletal muscle. Caveolin 3 is a principal structural protein of caveolae membrane domains in striated muscle cells and cardiac myocytes. Mutations of caveolin 3 gene (CAV3) cause different diseases and where caveolin 3 expression is defective, dysferlin localization is abnormal. We describe the alteration of dysferlin expression and localization in skeletal muscle from a patient with raised serum creatine kinase (hyperCKaemia), whose reduction of caveolin 3 is caused by a CAV3 P28L mutation. Moreover, we performed a study on dysferlin interaction with caveolin 3 in C2C12 cells. We show the association of dysferlin to cellular membrane of C2C12 myotubes and the low affinity link between dysferlin and caveolin 3 by immunoprecipitation techniques. We also reproduced caveolinopathy conditions in C2C12 cells by a selective p38 MAP kinase inhibition with SB203580, which blocks the expression of caveolin 3. In this model, myoblasts do not fuse into myotubes and we found that dysferlin expression is reduced. These results underline the importance of dysferlin-caveolin 3 relationship for skeletal muscle integrity and propose a cellular model to clarify the dysferlin alteration mechanisms in caveolinopathies

Consecuencias reproductivas de la hipocuprosis bovina: un avance hacia su diagnóstico y prevención en rodeos de Argentina

La deficiencia de cobre o hipocuprosis bovina genera pérdidas productivas por fallas inmunológicas y/o reproductivas. Su diagnóstico se realiza por análisis de cupremia, cuando las deficiencias son severas (< 30 μg/dL) aparecen las menores ganancias de peso. Sin embargo, no se conoce qué valores de cupremia podrían afectar la reproducción, con qué consecuencias y a través de qué mecanismos. Con el objetivo general de poder predecir y comprender las fallas reproductivas por hipocuprosis, se generaron objetivos particulares que fueron: 1. evaluar la asociación entre cupremias y niveles de cobre en licor folicular; 2. evaluar los niveles indicativos de carencia en el licor folicular con técnicas de fertilidad in vitro, como maduración in vitro de ovocitos, fertilización in vitro y desarrollo embrionario; y 3. evaluar en las células germinales y en los embriones en desarrollo la existencia de alteraciones asociadas a la falta de cobre. La asociación entre cupremias y concentración de cobre en licor folicular evidenció valores menores que en plasma y asociados a los mismos, por lo cual los valores de carencia en plasma implicaron niveles de carencia en el entorno del complejo-ovocito- cumulus. Para el segundo objetivo se prepararon medios de maduración in vitro con 0, 20, 40 y 60 μg/dL, indicativos de diferentes estatus de cobre. Los dos primeros generaron fallas en la maduración in vitro y en el desarrollo embrionario, demostrando las consecuencias de la carencia. Para evaluar las causas de estas fallas se realizaron técnicas que indicaron la existencia de daño oxidativo con aumento de daño en el ADN y disminución en la concentración de glutatión en ovocitos y células del cumulus. Con estos resultados se sugiere el diagnóstico mediante análisis de cupremias, y evitar que las hembras que ingresen en etapa reproductiva se encuentren en carencia severa.Copper deficiency causes production losses by immunological and/or reproductive failure. The diagnosis is made by analyzing cupraemia, when deficiencies are severe (<30 mg / dL) lower weight gains appear. However, the specific range of cupraemia could affect reproduction, with the consequences and mechanisms remain unknown. With the general objective of being able to predict and understand the reproductive failures by hypocuprosis, particular objectives were generated: 1. association of copper concentrations in plasma and follicular fluid from cattle ovaries; 2. the effects of supplemental copper during in vitro maturation on DNA damage of cumulus cells and glutathione content in oocytes and cumulus cells; and 3. supplementary copper during in vitro maturation on subsequent embryo development. The association between cupraemias and copper concentration in follicular fluid evidenced lower values in plasma and associated with them, so the values implied deficiency in plasma levels of deprivation in the environment of complex-ovocito- cumulus. For the second objective, in vitro maturation media prepared with 0, 20, 40 and 60 μg/dL, were indicative of different copper status. The 0 and 20 μg/dL generated failures in vitro maturation and embryonic development, demonstrating the consequences of the lack. To assess the causes of these failures techniques indicated the existence of oxidative damage with increased DNA damage and decreased concentration of glutathione in oocytes and cumulus cells were performed. These results suggest the diagnosis in a cow-calf operation by analyzing cupremias, and supplemented if necessary in the third period of gestation.Segunda Mención del Premio Biogénesis Bagó 2013.Academia Nacional de Agronomía y Veterinari