499 research outputs found
Relative Prym varieties associated to the double cover of an Enriques surface
Given an Enriques surface T , its universal K3 cover f : S → T , and a genus g linear system |C| on T, we construct the relative Prym variety PH = Prymv,H(D/C), where C → |C| and D → |f∗C| are the universal families, v is the Mukai vector (0, [D], 2−2g) and H is a polarization on S. The relative Prym variety is a (2g−2)-dimensional possibly singular variety, whose smooth locus is endowed with a hyperk ̈ahler structure. This variety is constructed as the closure of the fixed locus of a symplectic birational involution defined on the moduli space Mv,H (S). There is a natural Lagrangian fibration η : PH → |C|, that makes the regular locus of PH into an integrable system whose general fiber is a (g − 1)-dimensional (principally polarized) Prym variety, which in most cases is not the Jacobian of a curve. We prove that if |C| is a hyperelliptic linear system, then PH admits a symplectic resolution which is birational to a hyperk ̈ahler manifold of K3[g−1]-type, while if |C| is not hyperelliptic, then PH admits no symplectic resolution. We also prove that any resolution of PH is simply connected and, when g is odd, any resolution of PH has h2,0-Hodge number equal to one
The Hodge numbers of O'Grady 10 via Ng\^o strings
We determine the Hodge numbers of the hyper-K\"ahler manifold known as
O'Grady 10 by studying some related modular Lagrangian fibrations by means of a
refinement of the Ng\^o Support Theorem.Comment: Revised and final version to appear in Jour. Math. Pur. et App
Cardiovascular profile improvement during Natalizumab treatment
Cardiovascular comorbidities are associated with the risk of MS progression. Thus, we aim to measure variations of cardiovascular risk factors during Natalizumab treatment and their possible clinical associations. Seventy-one relapsing-remitting MS patients treated with Natalizumab were followed-up during a 12.9 ± 6.2 months. Cardiovascular risk factors were recorded on first and last study visits: systolic blood pressure, uric acid, total cholesterol, LDL, HDL, and triglycerides. EDSS progression and relapse occurrence were recorded. At multilevel mixed-effects linear regression models, the population presented with a significant reduction of total cholesterol (Coeff = -7.340; 95%CI = -13.152--1.527; p = 0.013), and of HDL cholesterol (Coeff = -3.473; 95%CI = -6.333--0.613; p = 0.017), and a non-significant reduction of LDL cholesterol (Coeff = -1.872; 95%CI = -8.481-0.736; p = 0.053), and of triglycerides (Coeff = -8.815; 95%CI = -34.011-5.380; p = 0.094). Uric acid levels increased during the study period (Coeff = 0.159; 95%CI = 0.212-0.340; p = 0.038). No significant associations were found with clinical outcomes. Serum lipids decreased and anti-oxidant uric acid increased during Natalizumab treatment. These biomarkers need to be further explored in relation to clinical outcomes on larger cohorts with longer follow-ups
Triple positive breast cancer. A distinct subtype?
Breast cancer is a heterogeneous disease, and within the HER-2 positive subtype this is highly exemplified by the presence of substantial phenotypical and clinical heterogeneity, mostly related to hormonal receptor (HR) expression. It is well known how HER-2 positivity is commonly associated with a more aggressive tumor phenotype and decreased overall survival and, moreover, with a reduced benefit from endocrine treatment. Preclinical studies corroborate the role played by functional crosstalks between HER-2 and estrogen receptor (ER) signaling in endocrine resistance and, more recently, the activation of ER signaling is emerging as a possible mechanism of resistance to HER-2 blocking agents. Indeed, HER-2 positive breast cancer heterogeneity has been suggested to underlie the variability of response not only to endocrine treatments, but also to HER-2 blocking agents. Among HER-2 positive tumors, HR status probably defines two distinct subtypes, with dissimilar clinical behavior and different sensitivity to anticancer agents. The triple positive subtype, namely, ER/PgR/Her-2 positive tumors, could be considered the subset which most closely resembles the HER-2 negative/HR positive tumors, with substantial differences in biology and clinical outcome. We argue on whether in this subgroup the "standard" treatment may be considered, in selected cases, i.e., small tumors, low tumor burden, high expression of both hormonal receptors, an overtreatment. This article review the existing literature on biologic and clinical data concerning the HER-2/ER/PgR positive tumors, in an attempt to better define the HER-2 subtypes and to optimize the use of HER-2 targeted agents, chemotherapy and endocrine treatments in the various subsets
Mitochondrial Damage in the Trabecular Meshwork Occurs Only in Primary Open-Angle Glaucoma and in Pseudoexfoliative Glaucoma
Open-angle glaucoma appears to be induced by the malfunction of the trabecular meshwork cells due to injury induced by oxidative damage and mitochondrial impairment. Here, we report that, in fact, we have detected mitochondrial damage only in primary open-angle glaucoma and pseudo-exfoliation glaucoma, among several glaucoma types compared.Mitochondrial damage was evaluated by analyzing the common mitochondrial DNA deletion by real-time PCR in trabecular meshwork specimens collected at surgery from glaucomatous patients and controls. Glaucomatous patients included 38 patients affected by various glaucoma types: primary open-angle, pigmented, juvenile, congenital, pseudoexfoliative, acute, neovascular, and chronic closed-angle glaucoma. As control samples, we used 16 specimens collected from glaucoma-free corneal donors. Only primary open-angle glaucoma (3.0-fold) and pseudoexfoliative glaucoma (6.3-fold) showed significant increases in the amount of mitochondrial DNA deletion. In all other cases, deletion was similar to controls.despite the fact that the trabecular meshwork is the most important tissue in the physiopathology of aqueous humor outflow in all glaucoma types, the present study provides new information regarding basic physiopathology of this tissue: only in primary open-angle and pseudoexfoliative glaucomas oxidative damage arising from mitochondrial failure play a role in the functional decay of trabecular meshwork
Inhibition of Stearoyl-CoA desaturase 1 reverts BRAF and MEK inhibition-induced selection of cancer stem cells in BRAF-mutated melanoma
Combination therapy with BRAF and MEK inhibitors significantly improves survival in BRAF mutated melanoma patients but is unable to prevent disease recurrence due to the emergence of drug resistance. Cancer stem cells (CSCs) have been involved in these long-term treatment failures. We previously reported in lung cancer that CSCs maintenance is due to altered lipid metabolism and dependent upon Stearoyl-CoA-desaturase (SCD1)-mediated upregulation of YAP and TAZ. On this ground, we investigated the role of SCD1 in melanoma CSCs
Subarachnoid versus General Anesthesia in Penile Prosthetic Implantation: Outcomes Analyses
The leading patient complaint during the perioperative period for penile prosthesis implantation is postoperative pain, while emesis and urticaria also affect the procedure’s perceived success. In analyzing surgical outcomes, assessment of the anesthetic for postoperative pain and side effects should be included. This paper retrospectively reviews 90 consecutive, primary inflatable penile prosthetic operations performed by a single surgeon at one private medical center. Fifty-seven patients were included in final analysis. Patients who had more than one procedure that day or who used chronic pain medication were excluded. The type and amount of each drug used for each respective side effect (within the first 24 hours after procedure) were compared to determine relative benefit. Twenty patients received general anesthesia (denoted herein as “GA”) and 37 received spinal (or also known as subarachnoid) anesthesia (denoted herein as “SA”). Patients receiving GA had significantly greater (P<0.0001) occurrence and amount of intravenous pain treatment than those receiving SA. Patients with SA required less intravenous pain medication and less treatment for nausea/emesis
Accidental finding of a toothpick in the porta hepatis during laparoscopic cholecystectomy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Unintentional ingestion of a toothpick is not an uncommon event. Often the ingested toothpicks spontaneously pass through the gut without sequelae. However, serious complications can happen when these sharp objects migrate through the gastrointestinal wall.</p> <p>Case presentation</p> <p>In the current report, we describe the case of a 37-year-old Caucasian woman with an incidental finding of a toothpick in the porta hepatis during laparoscopic cholecystectomy for symptomatic gall stones.</p> <p>Conclusion</p> <p>Toothpick ingestion is not an uncommon event and can predispose patients to serious complications. In this particular case, the toothpick was only discovered at the time of unrelated surgery. Therefore, it was important during surgery to exclude any related or missed injury to the adjacent structures by this sharp object.</p
Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae
Telomere capping conceals chromosome ends from exonucleases and checkpoints, but the full range of capping mechanisms is not well defined. Telomeres have the potential to form G-quadruplex (G4) DNA, although evidence for telomere G4 DNA function in vivo is limited. In budding yeast, capping requires the Cdc13 protein and is lost at nonpermissive temperatures in cdc13-1 mutants. Here, we use several independent G4 DNA-stabilizing treatments to suppress cdc13-1 capping defects. These include overexpression of three different G4 DNA binding proteins, loss of the G4 DNA unwinding helicase Sgs1, or treatment with small molecule G4 DNA ligands. In vitro, we show that protein-bound G4 DNA at a 3\u27 overhang inhibits 5\u27-\u3e 3\u27 resection of a paired strand by exonuclease I. These findings demonstrate that, at least in the absence of full natural capping, G4 DNA can play a positive role at telomeres in vivo
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