59 research outputs found

    A Model Structure for Enriched Coloured Operads

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    We prove that, under certain conditions, the model structure on a monoidal model category V\mathcal{V} can be transferred to a model structure on the category of V\mathcal{V}-enriched coloured (symmetric) operads. As a particular case we recover the known model structure on simplicial operads.Comment: 44 pages, Preliminary version, comments are welcom

    Rigidification of higher categorical structures

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    Given a limit sketch in which the cones have a finite connected base, we show that a model structure of "up to homotopy" models for this limit sketch in a suitable model category can be transferred to a Quillen equivalent model structure on the category of strict models. As a corollary of our general result, we obtain a rigidification theorem which asserts in particular that any Θn\Theta_n-space in the sense of Rezk is levelwise equivalent to one that satisfies the Segal conditions on the nose. There are similar results for dendroidal spaces and nn-fold Segal spaces.Comment: 30 pages, new introductio

    Morita homotopy theory for (∞,1)(\infty,1)-categories and ∞\infty-operads

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    We prove the existence of Morita model structures on the categories of small simplicial categories, simplicial sets, simplicial operads and dendroidal sets, modelling the Morita homotopy theory of (∞,1)(\infty,1)-categories and ∞\infty-operads. We give a characterization of the weak equivalences in terms of simplicial presheaves, simplicial algebras and slice categories. In the case of the Morita model structure for simplicial categories and simplicial operads, we also show that each of these model structures can be obtained as an explicit left Bousfield localization of the Bergner model structure on simplicial categories and the Cisinski--Moerdijk model structure on simplicial operads, respectively.Comment: 30 pages. v2: Sections 4 and 5 about the relation between Morita equivalences of algebraic theories and operads have been removed and made a separate note (arXiv:arXiv:1808.09045). The paper has been rewritten accordingly with minor modifications. v3: Final versio

    non invasive methods for the assessment of hepatic fibrosis transient elastography hyaluronic acid 13c aminopyrine breath test and cytokeratin 18 fragment

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    Background. In the management of chronic hepatitis C (CHC) patients, liver biopsy is the gold standard for liver fibrosis assessment despite some technical limits and risks. Non-invasive approaches have been proposed as alternative methods to evaluate structural liver damage. Aim. To investigate the diagnostic accuracy of transient elastography, 13C-aminopyrine breath test ( 13 C-ABT), serum hyaluronic acid (HA) and cytokeratin 18 Asp396 fragment (CK-18) as non-invasive methods of liver fibrosis assessment ad their correlation to METAVIR score. Material and methods. In a cohort of 57 CHC patients, liver stiffness, cumulative percentage of administered dose of 13C-aminopyrine at 120 min, serum HA and serum CK-18 concentration were determined. Diagnostic accuracy in detecting significant fibrosis (F ≥ 2), severe fibrosis (F ≥ 3) and cirrhosis (F = 4) was assessed by the area under the receiver operating characteristic curve. Results. Liver fibrosis score showed a strong correlation with liver stiffness (r = 0.667; p < 0.0001) and a significant inverse correlation with 13C-ABT results (r = -0.418; p = 0.0012). A weaker correlation was found with CK18 (r = 0.329; p = 0.0126) and no correlation with HA. Areas under the curve of elastography, 13C-ABT, HA and CK18 were: 0.98, 0.75, 0.69, 0.64, respectively, for F ≥ 2; 0.97, 0.69, 0.80, 0.66, respectively, for F ≥ 3; 0.95, 0.64, 0.70, 0.56, respectively, for F = 4. Conclusion. Elastography has the best diagnostic accuracy for the assessment of the degree of liver fibrosis in CHC patients. Its application can provide an alternative useful tool for monitoring the disease evolution

    Usefulness of a Hepatitis B Surface Antigen-Based Model for the Prediction of Functional Cure in Patients with Chronic Hepatitis B Virus Infection Treated with Nucleos(t)ide Analogues: A Real-World Study

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    In patients with chronic hepatitis B (CHB) under long-term treatment with nucleso(t)ide analogues (NAs), the loss of hepatitis B surface antigen (HBsAg) is a rare event. A growing body of evidence supports the use of quantitative HBsAg for the prediction of functional cure, although these results are mainly derived from studies performed on Asian patients with hepatitis B e antigen (HBeAg)-positive CHB. Here, we investigated the clinical role of quantitative HBsAg in a real-life cohort of CHB patients under treatment with NAs in a tertiary care center from North-West Italy. A total of 101 CHB patients (HBeAg-negative, n = 86) undergoing NAs treatment were retrospectively enrolled. HBsAg was measured at baseline (T0), 6 months (T1), 12 months (T2) and at the last follow-up (FU). Median FU was 5.5 (3.2–8.3) years; at the end of FU, 11 patients lost the HBsAg (annual incidence rate = 1.8%). Baseline HBsAg levels were significantly different between patients with no HBsAg loss and those achieving a functional cure (3.46, 2.91–3.97 vs. 1.11, 0.45–1.98 Log IU/mL, p < 0.001). Similarly, the HBsAg decline (Δ) from T0 to T2 was significantly different between the two groups of patients (0.05, −0.04–0.13, vs. 0.38, 0.11–0.80 Log IU/mL, p = 0.002). By stratified cross-validation analysis, the combination of baseline HBsAg and ΔHBsAg T0–T2 showed an excellent accuracy for the prediction of HBsAg loss (C statistic = 0.966). These results corroborate the usefulness of quantitative HBsAg in Caucasian CHB patients treated with antivirals for the prediction of HBsAg seroclearance

    IL28Bpolymorphism genotyping as predictor of rapid virologic response during interferon plus ribavirin treatment in hepatitis C virus genotype 1 patients

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    AIM: To clarify the association of interleukin-28B (IL28B) single nucleotide polymorphisms (SNPs) with hepatitis C virus (HCV) viremia changes for assessment of interferon (IFN) response. METHODS: A cohort of 118 Caucasian treatment-naïve HCV-G1 infected patients, treated with pegylated-IFN alpha 2a or 2b associated with ribavirin (53 responders, 65 non-responders) during the period 2010-2012, were genotyped for IL28B SNPs rs12979860 C>T and rs8099917 T>G. Genotyping was performed by real-time allelic discrimination assay. Serum HCV RNA levels were assayed at 2, 4, 12, 24 and 48 wk during therapy. Correlation between IL28B genotypes and serum HCV RNA kinetics was investigated. Multivariable logistic regression analysis was performed to identify predictors of null-response. RESULTS: Twenty-six out of 118 patients (22%) had no HCV RNA decline ≥ 1 log IU/mL at therapy week 4 (null-responders). IL28B genotype was rs8099917 (G*)/rs1297860(**) in 21/26 (80%) of null-responder patients. Using multivariate analysis, it was shown that the presence of the rs8099917 G allele was the best predictor of null-response (OR = 7.9, 95%CI: 1.99-31.18). The presence of at least one favorable genotype showed a positive predictive value of above 90% for HCV RNA reduction ≥ log at week 4. Analysis of the HCV RNA kinetics during 12 wk of therapy in patients with IL28B rs12979860 CT heterozygosis (n = 73), according to their rs8099917 status, showed that the viremia reduction was significantly different in patients carrying the rs8099917 G allele compared to those with favorable homozygosis. CONCLUSION: Our findings emphasize the association of the IL28B rs8099917 G allele with HCV. Genotyping for both IL28B SNPs is useful in clinical practice for thorough patient risk stratification based on IFN responsiveness

    Atopic dermatitis and ulcerative colitis successfully treated with upadacitinib

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    Background and Objectives: JAK inhibitors entered current clinical practice as treatment for several immune-related diseases and, recently, for atopic dermatitis. These drugs target the Janus Kinase intracellular cascade, rendering them suitable for treating both Th1 and Th2 immune-mediated responses. Materials and Methods: We report the case of a 36-year-old male patient presenting an overlap of ulcerative colitis, a Th1-related disease, and atopic dermatitis, a Th2-mediated condition. Treatment with upadacitinib was initiated, and laboratory and instrumental follow-ups were carried out for 8 months. Results: The complete and persistent clinical remission of both conditions was observed at a low dose of 15 mg of upadacitinib, even though ulcerative colitis guidelines usually recommend a dosage of 45 mg. No serious adverse responses to therapy were reported. Conclusions: Upadacitinib may be the most suitable management strategy in subjects with coexisting severe conditions mediated by Th1 inflammation, such as ulcerative colitis, and by Th2 cytokines, such as atopic dermatitis
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