4,284 research outputs found

    Moser's estimates for degenerate Kolmogorov equations with non-negative divergence lower order coefficients

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    We prove Lloc 1e estimates for positive solutions to the following degenerate second order partial differential equation of Kolmogorov type with measurable coefficients of the form 11i,j=1m0 02xjavax.xml.bind.JAXBElement@14c7905daij(x,t) 02xjavax.xml.bind.JAXBElement@41a3b5feu(x,t)+ 11i,j=1Nbijxj 02xjavax.xml.bind.JAXBElement@21dceba6u(x,t) 12 02tu(x,t)++ 11i=1m0bi(x,t) 02iu(x,t) 12 11i=1m0 02xjavax.xml.bind.JAXBElement@638b72d3ai(x,t)u(x,t)+c(x,t)u(x,t)=0 where (x,t)=(x1,\u2026,xN,t)=z is a point of RN+1, and 1 64m0 64N. (aij) is a uniformly positive symmetric matrix with bounded measurable coefficients, (bij) is a constant matrix. We apply the Moser's iteration method to prove the local boundedness of the solution u under minimal integrability assumption on the coefficients

    Metallothionein gene family in the sea urchin Paracentrotus lividus: Gene structure, differential expression and phylogenetic analysis

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    Metallothioneins (MT) are small and cysteine-rich proteins that bind metal ions such as zinc, copper, cadmium, and nickel. In order to shed some light on MT gene structure and evolution, we cloned seven Paracentrotus lividus MT genes, comparing them to Echinodermata and Chordata genes. Moreover, we performed a phylogenetic analysis of 32 MTs from different classes of echinoderms and 13 MTs from the most ancient chordates, highlighting the relationships between them. Since MTs have multiple roles in the cells, we performed RT-qPCR and in situ hybridization experiments to understand better MT functions in sea urchin embryos. Results showed that the expression of MTs is regulated throughout development in a cell type-specific manner and in response to various metals. The MT7 transcript is expressed in all tissues, especially in the stomach and in the intestine of the larva, but it is less metal-responsive. In contrast, MT8 is ectodermic and rises only at relatively high metal doses. MT5 and MT6 expression is highly stimulated by metals in the mesenchyme cells. Our results suggest that the P. lividus MT family originated after the speciation events by gene duplications, evolving developmental and environmental sub-functionalization

    An intronic cis-regulatory element is crucial for the alpha tubulin Pl-Tuba1a gene activation in the ciliary band and animal pole neurogenic domains during sea urchin development

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    In sea urchin development, structures derived from neurogenic territory control the swimming and feeding responses of the pluteus as well as the process of metamorphosis. We have previously isolated an alpha tubulin family member of Paracentrotus lividus (Pl-Tuba1a, formerly known as Pl-Talpha2) that is specifically expressed in the ciliary band and animal pole neurogenic domains of the sea urchin embryo. In order to identify cis-regulatory elements controlling its spatio-temporal expression, we conducted gene transfer experiments, transgene deletions and site specific mutagenesis. Thus, a genomic region of about 2.6 Kb of Pl-Tuba1a, containing four Interspecifically Conserved Regions (ICRs), was identified as responsible for proper gene expression. An enhancer role was ascribed to ICR1 and ICR2, while ICR3 exerted a pivotal role in basal expression, restricting Tuba1a expression to the proper territories of the embryo. Additionally, the mutation of the forkhead box consensus sequence binding site in ICR3 prevented Pl-Tuba1a expression

    Phosphodiesterase inhibitors: Could they be beneficial for the treatment of COVID-19?

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    In March 2020, the World Health Organization declared the severe acute respiratory syndrome corona virus 2 (SARS-CoV2) infection to be a pandemic disease. SARS-CoV2 was first identified in China and, despite the restrictive measures adopted, the epidemic has spread globally, becoming a pandemic in a very short time. Though there is growing knowledge of the SARS-CoV2 infection and its clinical manifestations, an effective cure to limit its acute symptoms and its severe complications has not yet been found. Given the worldwide health and economic emergency issues accompanying this pandemic, there is an absolute urgency to identify effective treatments and reduce the post infection outcomes. In this context, phosphodiesterases (PDEs), evolutionarily conserved cyclic nucleotide (cAMP/cGMP) hydrolyzing enzymes, could emerge as new potential targets. Given their extended distribution and modulating role in nearly all organs and cellular environments, a large number of drugs (PDE inhibitors) have been developed to control the specific functions of each PDE family. These PDE inhibitors have already been used in the treatment of pathologies that show clinical signs and symptoms completely or partially overlapping with post-COVID-19 conditions (e.g., thrombosis, inflammation, fibrosis), while new PDE-selective or pan-selective inhibitors are currently under study. This review discusses the state of the art of the different pathologies currently treated with phosphodiesterase inhibitors, highlighting the numerous similarities with the disorders linked to SARS-CoV2 infection, to support the hypothesis that PDE inhibitors, alone or in combination with other drugs, could be beneficial for the treatment of COVID-19

    RT-PCR and in situ hybridization analysis of apolipoprotein H expression in rat normal tissues

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    In this study, by using different techniques (i.e. Northern blot hybridization, RT-PCR and Southern blot hybridization) on various normal rat tissues, we were able to identify liver, kidney, heart, small intestine, brain, spleen, stomach and prostate as tissues in which the ApoH gene is transcribed. Moreover, for some of these tissues, by in situ hybridization, we found a specific localization of apoH transcripts. For instance epithelial cells of the bile ducts in liver and of the proximal tubules in kidney are the major sites of apoH synthesis. Our data suggest that some of the different physiological roles proposed for apoH could correlate with its direct expression, while others could correlate with its absorption from bloodstream or adjacent cells

    Structure analysis of the virtual Compton scattering amplitude at low energies

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    We analyze virtual Compton scattering off the nucleon at low energies in a covariant, model-independent formalism. We define a set of invariant functions which, once the irregular nucleon pole terms have been subtracted in a gauge-invariant fashion, is free of poles and kinematical zeros. The covariant treatment naturally allows one to implement the constraints due to Lorentz and gauge invariance, crossing symmetry, and the discrete symmetries. In particular, when applied to the epepγep\to e'p'\gamma reaction, charge-conjugation symmetry in combination with nucleon crossing generates four relations among the ten originally proposed generalized polarizabilities of the nucleon.Comment: 19 pages, LaTeX2e/RevTeX, no figures, original sections IV.-VI. removed, to be discussed in a separate publication, none of the conclusions change

    Thyroid autoimmune disorders and cancer

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    In the last decades, many studies conducted in vitro, and in vivo, have shown that thyroid autoimmunity and thyroid cancer (TC) (mainly papillary TC) can be concomitant, even if the exact mechanisms at the basis of this association are still not clear. Growing incidence of TC coincides with increased registration of autoimmune thyroid disorders (AITD) suggesting an association between those pathologies. Elevated TSH levels and thyroid autoimmunity were defined as independent risk factors for TC. However a lot of evidence suggests that autoimmunity and inflammation, per se, are risk factors for TC. The link between inflammation and TC involves multiple components of the immune system, extracellular matrix, stroma, and adipose tissue, with pro-tumoral activity of inflammation being opposed to anti-inflammatory effects, favoring protection against cancer progression. Within the tumor microenvironment, inflammatory cells, belonging both to innate (macrophages) and adaptive (lymphocytes) immune responses, are interconnected with fibroblasts, endothelial cells, adipocytes, and extracellular matrix through cytokines, chemokines and adipocytokines. Under the influence of transcriptional regulators (such as Nuclear Factor-kappa B, mitogen-activated protein kinases, or Phosphoinositide-3 kinase/protein kinase-B), oncogenes connected to the different subtypes of TC promote their farthermost proliferative effect on the tumor microenvironment. Future studies will be necessary to understand the connections between thyroid autoimmunity and cancer, also in order to design a tailored therapy for TC patients with AITD

    The Stability of TSH, and Thyroid Hormones, in Patients Treated With Tablet, or Liquid Levo-Thyroxine

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    Approximately, 5% of the population is affected by hypothyroidism, mainly women and persons aged more than 60 years. After the diagnosis of hypothyroidism the usual therapy is tablet levothyroxine (L-T4), with a monitoring of the thyroid-stimulating hormone (TSH) level in primary hypothyroidism every 6-8 weeks and L-T4 is adjusted as necessary to reach an euthyroid state. Once TSH is stabilized in the normal range, it is recommended to conduct annual testing in the treated subjects to warrant suitable replacement. More recently advances regarding L-T4 treatment are the introduction of new oral formulations: the liquid solution, and soft gel capsule. The soft gel capsule permits a quick dissolution in the acid gastric pH. The liquid preparation does not require an acid gastric environment. Many pharmacokinetic studies demonstrated a more rapid absorption for the liquid L-T4, or capsule, than with tablet. Many studies have shown that the liquid, or capsule, formulations can overcome the interaction with foods, drugs or malabsorptive conditions, that are able to impair the tablet L-T4 absorption. Lately studies have suggested that liquid L-T4 can permit to maintain more efficiently normal TSH levels in hypothyroid patients in the long-term follow-up, than tablet L-T4, both in patients with malabsorptive states, and in those without malabsorption. Further large, prospective, longitudinal studies are needed to evaluate the stability of TSH, in hypothyroid patients treated with different L-T4 formulations

    Complete one-loop analysis of the nucleon's spin polarizabilities

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    We present a complete one-loop analysis of the four nucleon spin polarizabilities in the framework of heavy baryon chiral perturbation theory. The first non-vanishing contributions to the isovector and first corrections to the isoscalar spin polarizabilities are calculated. No unknown parameters enter these predictions. We compare our results to various dispersive analyses. We also discuss the convergence of the chiral expansion and the role of the delta isobar.Comment: 4 pp, REVTE
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