496 research outputs found

    First and second variation formulae for the sub-Riemannian area in three-dimensional pseudo-hermitian manifolds

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    We calculate the first and the second variation formula for the sub-Riemannian area in three dimensional pseudo-hermitian manifolds. We consider general variations that can move the singular set of a C^2 surface and non-singular variation for C_H^2 surfaces. These formulas enable us to construct a stability operator for non-singular C^2 surfaces and another one for C2 (eventually singular) surfaces. Then we can obtain a necessary condition for the stability of a non-singular surface in a pseudo-hermitian 3-manifold in term of the pseudo-hermitian torsion and the Webster scalar curvature. Finally we classify complete stable surfaces in the roto-traslation group RT .Comment: 36 pages. Misprints corrected. Statement of Proposition 9.8 slightly changed and Remark 9.9 adde

    Basic properties of nonsmooth Hormander's vector fields and Poincare's inequality

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    We consider a family of vector fields defined in some bounded domain of R^p, and we assume that they satisfy Hormander's rank condition of some step r, and that their coefficients have r-1 continuous derivatives. We extend to this nonsmooth context some results which are well-known for smooth Hormander's vector fields, namely: some basic properties of the distance induced by the vector fields, the doubling condition, Chow's connectivity theorem, and, under the stronger assumption that the coefficients belong to C^{r-1,1}, Poincare's inequality. By known results, these facts also imply a Sobolev embedding. All these tools allow to draw some consequences about second order differential operators modeled on these nonsmooth Hormander's vector fields.Comment: 60 pages, LaTeX; Section 6 added and Section 7 (6 in the previous version) changed. Some references adde

    Baseline serum TSH levels predict the absence of thyroid dysfunction in cancer patients treated with immunotherapy

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    Purpose Immunotherapy against immune checkpoints has significantly improved survival both in metastatic and adjuvant setting in several types of cancers. Thyroid dysfunction is the most common endocrine adverse event reported. Patients who are at risk of developing thyroid dysfunction remain to be defined. We aimed to identify predictive factors for the develop- ment of thyroid dysfunction during immunotherapy. Methods This is a retrospective study including a total of 68 patients who were treated with immune checkpoint inhibi- tors (ICIs) for metastatic or unresectable advanced cancers. The majority of patients were treated with anti-PD1 drugs in monotherapy or in combination with anti-CTLA4 inhibitors. Thyroid function and anti-thyroid antibodies, before starting immunotherapy and during treatment, were evaluated. Thyroid ultrasound was also performed in a subgroup of patients at the time of enrolment in the study. Results Eleven out of 68 patients (16.1%) developed immune-related overt thyroid dysfunction. By ROC curve analysis, we found that a serum TSH cut-off of 1.72 mUI/l, at baseline, had a good diagnostic accuracy in identifying patients without overt thyroid dysfunction (NPV = 100%, p = 0.0029). At multivariate analysis, both TSH and positive anti-thyroid antibod- ies (ATAbs) levels, before ICIs treatment, were independently associated with the development of overt thyroid dysfunction during immunotherapy (p = 0.0001 and p = 0.009, respectively). Conclusions Pre-treatment serum TSH and ATAbs levels may help to identify patients at high risk for primary thyroid dysfunction. Our study suggests guidance for an appropriate timely screening and for a tailored management of thyroid dysfunctions in patients treated with ICIs

    Light-Enhanced Cytotoxicity of Doxorubicin by Photoactivation

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    The combination of photodynamic therapy with chemotherapy (photochemotherapy, PCT) can lead to additive or synergistic antitumor effects. Usually, two different molecules, a photosensitizer (PS) and a chemotherapeutic drug are used in PCT. Doxorubicin is one of the most successful chemotherapy drugs. Despite its high efficacy, two factors limit its clinical use: severe side effects and the development of chemoresistance. Doxorubicin is a chromophore, able to absorb light in the visible range, making it a potential PS. Here, we exploited the intrinsic photosensitizing properties of doxorubicin to enhance its anticancer activity in leukemia, breast, and epidermoid carcinoma cells, upon irradiation. Light can selectively trigger the local generation of reactive oxygen species (ROS), following photophysical pathways. Doxorubicin showed a concentration-dependent ability to generate peroxides and singlet oxygen upon irradiation. The underlying mechanisms leading to the increase in its cytotoxic activity were intracellular ROS generation and the induction of necrotic cell death. The nuclear localization of doxorubicin represents an added value for its use as a PS. The use of doxorubicin in PCT, simultaneously acting as a chemotherapeutic agent and a PS, may allow (i) an increase in the anticancer effects of the drug, and (ii) a decrease in its dose, and thus, its dose-related adverse effects

    Two-Photon Dichroic Atomic Vapor Laser Lock Using Electromagnetically Induced Transparency and Absorption

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    We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S 1/2, 5P 3/2, and 5D 5/2 levels. This atomic configuration can show Electromagnetically Induced Transparency and Absorption processes. The error signal comes from the difference in the transparency or absorption felt by the two orthogonal polarizations of the probe beam. A simplified model is in good quantitative agreement with the observed signals for the experimental parameters. We have used this technique to lock the frequency of the laser up to 1.5 GHz off atomic resonance.Comment: 6 pages, 8 figures. Last version for publication in J. Opt. Soc. Am.

    Clinical experience with ipilimumab 10 mg/kg in patients with melanoma treated at Italian centres as part of a European expanded access programme

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    Background: Patients with advanced melanoma are faced with a poor prognosis and, until recently, limited treatment options. Ipilimumab, a novel immunotherapy that blocks cytotoxic T-lymphocyte-associated antigen-4, was the first agent to improve survival of patients with advanced melanoma in a randomised, controlled phase 3 trial. We used data from an expanded access programme (EAP) at Italian centres to evaluate the clinical activity and safety profile of ipilimumab 10 mg/kg in patients with advanced melanoma in a setting more similar to that of daily practice. Methods. Data were collected from patients enrolled in an ipilimumab EAP across eight participating Italian centres. As per the EAP protocol, patients had life-threatening, unresectable stage III/IV melanoma, had failed or did not tolerate previous treatments and had no other therapeutic option available. Treatment comprised ipilimumab 10 mg/kg every 3 weeks for a total of four doses. If physicians believed patients would continue to derive benefit from ipilimumab treatment, maintenance therapy with ipilimumab 10 mg/kg was provided every 12 weeks. Tumour responses were assessed every 12 weeks using modified World Health Organization criteria and safety continuously monitored. Results: Seventy-four pretreated patients with advanced melanoma were treated with ipilimumab 10 mg/kg. Of these, 9 (13.0%) had an objective response, comprising 3 patients with a complete response and 6 with a partial response. Median overall survival was 7.0 months (95% confidence interval, 5.3-8.7) and 16.6% of patients were alive after 3 years. Forty-five patients (60.8%) reported treatment-related adverse events of any grade, which were most commonly low-grade pruritus, pain, fever and diarrhoea. Grade 3 or 4 treatment-related AEs were reported in 8 patients (10.8%). Conclusions: The clinical activity and safety profile of ipilimumab 10 mg/kg in the EAP was similar to that seen in previous clinical trials of ipilimumab in pretreated patient populations. © 2013 Altomonte et al.; licensee BioMed Central Ltd

    Context-specific regulation of surface and soluble IL7R expression by an autoimmune risk allele.

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    IL-7 is a key factor in T cell immunity and common variants at IL7R, encoding its receptor, are associated with autoimmune disease susceptibility. IL7R mRNA is induced in stimulated monocytes, yet a function for IL7R in monocyte biology remains unexplored. Here we characterize genetic regulation of IL7R at the protein level in healthy individuals, and find that monocyte surface and soluble IL7R (sIL7R) are markedly induced by lipopolysaccharide. In monocytes, both surface IL7R and sIL7R expression strongly associate with allelic carriage of rs6897932, a disease-associated IL7R polymorphism. Monocytes produce more sIL7R than CD4 + T cells, and the amount is additionally correlated with the expression of DDX39A, encoding a splicing factor. Synovial fluid-derived monocytes from patients with spondyloarthritis are enriched for IL7R+ cells with a unique transcriptional profile that overlaps with IL-7-induced gene sets. Our data thus suggest a previously unappreciated function for monocytes in IL-7 biology and IL7R-associated diseases

    Essential oil composition and antichemotactic activity of Stenachaenium Benth. species native to South Brazil

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    Chemical composition of essential oils from four Stenachaenium species from South Brazil were established by gas chromatography coupled with mass spectrometry (GC/MS). The major compounds identified in the oil of S. megapotamicum were a coumarin derivative, 2H-1-benzopyran-2-one,7-(3-methylbutoxy) (24.0%), β-bisabolene (12.8%) and thymol methyl ether (7.1%). The oil of S. adenanthum contained mainly pogostol (14.0%). S. riedelli oil showed significant presence of aliphatic compounds, with predominance of hexadecanoic acid in all samples (leaves, inflorescence and leaves collected during of inflorescence period). Hexadecanoic acid (23.8%) was also the main component in S. macrocephalum. Concerning antichemotactic activity, all the oil samples tested showed a significant leukocyte migration inhibition compared to chemotactic stimulant (lipopolysaccharide from Escherichia coli - LPS), at concentrations of 1 to 5 μg/mL, except for S. adenanthum. These results suggest that the essential oils of some Stenachaenium species could inhibit acute inflammatory process, because the migration of neutrophils occurs mainly in the early inflammatory process
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