2,364 research outputs found
A precise new KLOE measurement of with ISR events and determination of contribution to for GeV
The KLOE experiment at the DANE -factory has performed a new
precise measurement of the pion form factor using Initial State Radiation
events, with photons emitted at small polar angle. Results based on an
integrated luminosity of 240 pb and extraction of the
contribution to in the mass range GeV are
presented. The new value of has smaller (30%) statistical and
systematic error and is consistent with the KLOE published value (confirming
the current disagreement between the standard model prediction for and
the measured value).Comment: 5 pages, proceedings for the CIPANP 2009 conferenc
Incoherent pion photoproduction on the deuteron in the first resonance region
Incoherent pion photoproduction on the deuteron is studied in the first
resonance region. The unpolarized cross section, the beam asymmetry, and the
vector and tensor target asymmetries are calculated in the framework of a
diagrammatic approach. Pole diagrams and one-loop diagrams with scattering
in the final state are taken into account. An elementary operator for pion
photoproduction on the nucleon is taken in various on-shell forms and
calculated using the SAID and MAID multipole analyses. Model dependence of the
obtained results is discussed in some detail. A comparison with predictions of
other works is given. Although a reasonable description of many available
experimental data on the unpolarized total and differential cross sections and
photon asymmetry has been achieved, in some cases a significant disagreement
between the theory and experiment has been found. Invoking known information on
the reactions and we predict the total
photoabsorption cross section for deuterium. We find that our values strongly
overestimate experimental data in the vicinity of the peak.Comment: 22 pages, 23 figure
Quasifree pion photoproduction on the deuteron in the region
Photo production of pions on the deuteron is studied in the spectator nucleon
model. The Born terms of the elementary production amplitude are determined in
pseudovector N coupling and supplied with a form factor. The
resonance is considered both in the and the channel. The parameters of
the resonance and the cutoff of the form factors are fixed on the
leading photoproduction multipoles. Results for total and differential cross
sections are compared with experimental data. Particular attention is paid to
the role of Pauli correlations of the final state nucleons in the quasifree
case. The results are compared with those for pion photoproduction on the
nucleon.Comment: 17 pages LateX2e including 5 postscript figure
Case Report: Ipilimumab-Induced Panhypophysitis: An Infrequent Occurrence and Literature Review
BackgroundImmune checkpoint inhibitors (ICIs), by unleashing the anticancer response of the immune system, can improve survival of patients affected by several malignancies, but may trigger a broad spectrum of adverse events, including autoimmune hypophysitis. ICI-related hypophysitis mainly manifests with anterior hypopituitarism, while the simultaneous involvement of both anterior and posterior pituitary (i.e., panhypophysitis) has rarely been described.Case PresentationIn June 2015, a 64-year-old man affected by liver metastases of a uveal melanoma was referred to us due to polyuria and polydipsia. Two months prior, he had started ipilimumab therapy (3 mg/kg iv every 21 days). The treatment was well-tolerated (only mild asthenia and diarrhea were reported). A few days before the fourth cycle, the patient complained of intense headaches, profound fatigue, nocturia, polyuria (up to 10 L urine/daily), and polydipsia. Laboratory tests were consistent with adrenal insufficiency, hypothyroidism, and transient central diabetes insipidus. The pituitary MRI showed an enlarged gland with microinfarcts, while the hypophyseal stalk was normal, and the neurohypophyseal 'bright signal' in T1 sequences was not detected. The treatment included dexamethasone (then cortisone acetate at replacement dose), desmopressin, and levothyroxine. Within the next five days, the symptoms resolved, and blood pressure, electrolytes, glucose, and urinalysis were stable within the normal ranges; desmopressin was discontinued while cortisone acetate and levothyroxine were maintained. The fourth ipilimumab dose was entirely administered in the absence of further side effects.ConclusionAs ICIs are increasingly used as anticancer agents, the damage to anterior and/or posterior pituitary can be progressively encountered by oncologists and endocrinologists in their clinical practice. Patients on ICIs and their caregivers should be informed about that risk and be empowered to alert the referring specialists early, at the onset of panhypopituitarism symptoms, including polyuria/polydipsia
Transcriptional Regulation of Glucose Metabolism: The Emerging Role of the HMGA1 Chromatin Factor
HMGA1 (high mobility group A1) is a nonhistone architectural chromosomal protein that functions mainly as a dynamic regulator of chromatin structure and gene transcription. As such, HMGA1 is involved in a variety of fundamental cellular processes, including gene expression, epigenetic regulation, cell differentiation and proliferation, as well as DNA repair. In the last years, many reports have demonstrated a role of HMGA1 in the transcriptional regulation of several genes implicated in glucose homeostasis. Initially, it was proved that HMGA1 is essential for normal expression of the insulin receptor (INSR), a critical link in insulin action and glucose homeostasis. Later, it was demonstrated that HMGA1 is also a downstream nuclear target of the INSR signaling pathway, representing a novel mediator of insulin action and function at this level. Moreover, other observations have indicated the role of HMGA1 as a positive modulator of the Forkhead box protein O1 (FoxO1), a master regulatory factor for gluconeogenesis and glycogenolysis, as well as a positive regulator of the expression of insulin and of a series of circulating proteins that are involved in glucose counterregulation, such as the insulin growth factor binding protein 1 (IGFBP1), and the retinol binding protein 4 (RBP4). Thus, several lines of evidence underscore the importance of HMGA1 in the regulation of glucose production and disposal. Consistently, lack of HMGA1 causes insulin resistance and diabetes in humans and mice, while variations in the HMGA1 gene are associated with the risk of type 2 diabetes and metabolic syndrome, two highly prevalent diseases that share insulin resistance as a common pathogenetic mechanism. This review intends to give an overview about our current knowledge on the role of HMGA1 in glucose metabolism. Although research in this field is ongoing, many aspects still remain elusive. Future directions to improve our insights into the pathophysiology of glucose homeostasis may include epigenetic studies and the use of "omics" strategies. We believe that a more comprehensive understanding of HMGA1 and its networks may reveal interesting molecular links between glucose metabolism and other biological processes, such as cell proliferation and differentiation
A rare case of pituitary melanoma metastasis: a dramatic and prolonged response to dabrafenib-trametinib therapy
Introduction: Pituitary metastases (PM) are rare events and to date only very few cases of melanoma PM have been described in literature up to now. Case Presentation: We describe the clinical history of a 33-year-old male patient who underwent surgical excision of an inter-scapular melanoma in 2008. The subsequent follow-up was negative for ~10 years. In September 2018, due to the onset of a severe headache, the patient underwent a brain magnetic resonance imaging, which showed an expansive mass in the saddle and suprasellar region with a maximum diameter of 17 mm. Pituitary function tests and visual field were normal. Worsening of the headache and the appearance of a left eye ptosis led the patient to surgical removal of the lesion in October 2018. The histological examination unexpectedly showed metastasis of the melanoma. Post-operative hormonal assessment showed secondary hypothyroidism and hypoadrenalism, which were both promptly treated, and a mild hypogonadism. Three months after surgery, a sellar MRI showed a persistent, increased pituitary mass (3 cm of diameter); fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) detected an increased radiopharmaceutical uptake in the sellar region. Due to the persistence of the disease and the evidence of a BRAF V600E mutation, in February 2019, the patient underwent a combined treatment with dabrafenib (a BRAF inhibitor) and trametinib (mitogen-activated extracellular signal-regulate kinase inhibitor). Sellar MRI performed 6 months later showed no evidence of mass in the sellar region. The patient was in a good clinical condition and did not complain of headaches or other symptoms; there were no significant side-effects from the anticancer therapy. After 13 months of treatment, the patient showed no recurrence of the disease on morphological imaging. Anticancer therapy was confirmed, replacement therapies with hydrocortisone and levothyroxine continued and the pituitary-gonadal axis was restored. Conclusion: This is a very interesting case, both for the rarity of the pituitary melanoma metastasis and for the singular therapeutic course carried out by the patient. This is the first case of a pituitary melanoma metastasis with BRAF mutation, successfully treated with the combination of dabrafenib and trametinib after incomplete surgical removal
Study of the a_0(980) meson via the radiative decay phi->eta pi^0 gamma with the KLOE detector
We have studied the phi->a_0(980) gamma process with the KLOE detector at the
Frascati phi-factory DAPhNE by detecting the phi->eta pi^0 gamma decays in the
final states with eta->gamma gamma and eta->pi^+ pi^- pi^0. We have measured
the branching ratios for both final states: Br(phi->eta pi^0 gamma)=(7.01 +/-
0.10 +/- 0.20)x10^-5 and (7.12 +/- 0.13 +/- 0.22)x10^-5 respectively. We have
also extracted the a_0(980) mass and its couplings to eta pi^0, K^+ K^-, and to
the phi meson from the fit of the eta pi^0 invariant mass distributions using
different phenomenological models.Comment: 17 pages, 6 figures, submitted to Physics Letters B. Corrected typos
in eq.
Charged kaon lifetime at KLOE
Preliminary result on the charged kaon lifetime, obtained by the KLOE
experiment operating at DANE, the Frascati -factory, is presentedComment: 3 pages, 3 figures, to appear in the proceedings of 42nd Rencontres
de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 10-17 Mar 200
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