86,754 research outputs found
Slow radioactive saliva transit through the esophagus mimicking a mediastinal thyroid mass in a patient with myasthenia gravis
No full textExploring the Role of Hamiltonian Expressibility in Ansatz Selection for Variational Quantum Algorithms
No full textA key challenge in Variational Quantum Algorithms (VQAs) consists in designing effective parametric quantum circuits, or ansatzes, that account for both the specific problem and the limitations of quantum hardware. While Machine Learning-based methods for circuit construction have been developed, selecting the appropriate metrics to include in the cost function to ensure the circuit has the desired properties remains a non-trivial task. Hamiltonian expressibility has been proposed as a metric to quantify a circuit ability to explore the problem energy landscape. However, its potential to enhance the likelihood of obtaining high-quality solutions remains underexplored. In this work, we investigate the correlation between an ansatz Hamiltonian expressibility and the quality of solutions found using the Variational Quantum Eigensolver (VQE), aiming to determine whether such metric could enhance Machine Learning methods for ansatz design. Specifically, we propose a protocol to estimate the Hamiltonian expressibility of a given ansatz and Hamiltonian, and employ VQE to solve the associated optimization problem. By conducting a correlation analysis, we assess the relationship between Hamiltonian expressibility and solution quality. Our results suggest that Hamiltonian expressibility could serve as a valuable metric to enhance Machine Learning techniques used for ansatz design
S100B protein interacts with and activates Src kinase in astrocytes thereby regulating cell shape and migration: implications for astrocyte development, activation and tumor growth.
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Investigation of small non-coding RNA modulation in islet macrophages during obesity and diabetes
No full textS100B-induced increase in proliferation and decrease in NGF sensitivity of PC12 cells depends on PI3-K/Akt (PKB) activation
No full textS100B increases proliferation in PC12 neuronal cells and reduces their responsiveness to NGF via Akt activation
No full textS100B is a Ca2+-modulated protein of the EF-hand type expressed in high abundance in a restricted set of cell types including certain neuronal populations. S100B has been suggested to participate in cell cycle progression, and S100B levels are high in tumor cells, compared with normal parental cells. We expressed S100B in the neuronal cell line PC12, which normally does not express the protein, by the Tet-Off technique, and found the following: (i) proliferation was higher in S100B+ PC12 cells than in S100B- PC12 cells; (ii) nerve growth factor (NGF), which decreased the proliferation of S100B- PC12 cells, was less effective in the case of S100B+ PC12 cells; (iii) expression of S100B made PC12 cells resistant to the differentiating effect of NGF; and (iv) interruption of S100B expression did not result in an immediate restoration of PC12 cell sensitivity to the differentiating effect of NGF. Expression of S100B in PC12 cells resulted in activation of Akt; increased levels of p21WAF1, an inhibitor of cyclin-dependent kinase (cdk) 2 and a positive regulator of cdk4; increased p21WAF1-cyclin D1 complex formation; and increased phosphorylation of the retinoblastoma suppressor protein, Rb. These S100B-induced effects, as well as the reduced ability of S100B+ PC12 cells to respond to NGF, were dependent on Akt activation because they were remarkably reduced or abrogated in the presence of LY294002, an inhibitor of the Akt upstream kinase phosphatidylinositol 3-kinase. Thus, S100B might promote cell proliferation and interfere with NGF-induced PC12 cell differentiation by stimulating a p21WAF1/cyclin D1/cdk4/Rb/E2F pathway in an Akt-mediated manner
Area di intensa iodocaptazione al WBS con 131I simulante metastasi polmonare causata da angioma capillare a basso flusso.
No full textINTRODUZIONE: Il follow-up del carcinoma differenziato della tiroide (DTC) si basa sul dosaggio della Tireoglobulina (Tg), sull’ecografia color Doppler (CFDS) del collo e sulla scintigrafia totale corporea (WBS) con 131I. Quest’ultima indagine permette di identificare aree di recidiva o metastasi di DTC iodofissanti, ma raramente può essere inficiata da falsi positivi.
CASO CLINICO: La paziente in oggetto (aa 71) era stata sottoposta nel 2002 a tiroidectomia totale e terapia radiometabolica con 100 mCi di 131I per carcinoma papillare (T2N0M0). E’stata successivamente sottoposta a 2 WBS in ipotiroidismo risultati negativi con Tg <1,0 ng/ml. Un recente dosaggio della Tg con tecnica più sensibile sotto terapia TSH soppressiva evidenziava un valore di 0,6 ng/ml; gli anticorpi anti Tg (AbTg) erano indosabili e il CFDS del collo nella norma. La paziente è stata quindi sottoposta a terapia con 131I (150 mCi) dopo stimolo con TSH umano ricombinante (rh-TSH). La Tg basale si confermava dosabile (0,508 ng/ml) senza subire significative variazioni dopo stimolo con rh-TSH (0,525 ng/ml). Il WBS post-dose evidenziava un’area di fissazione in sede mediana sovraioidea compatibile con residuo di dotto tireoglosso ed un’area di marcata attività nella porzione basale dell’emitorace dx, riferibile in prima istanza a metastasi polmonare. Una successiva TC torace con mdc evidenziava in corrispondenza dell’area ipercaptante la presenza di “multiple formazioni ipodense, verosimilmente intravasali lungo il decorso del bronco postero-basale del lobo destro, compatibili con esito di embolia polmonare o infarto parenchimale”. Una successiva angio-TC del torace evidenziava “piccola opacità basale dx a margini regolari che si impregna lentamente e costantemente di mdc, compatibile per morfologia ed enhancement con angioma capillare a basso flusso.”
DISCUSSIONE: I falsi positivi del WBS con 131I descritti in letteratura riconoscono diversi meccanismi: secrezioni corporee (ristagno di saliva), essudati patologici (pericardico e pleurico), infiammazioni, tumori non tiroidei (oltre a struma ovarii, carcinomi polmonari, adenocarcinomi e meningiomi), rallentamento della motilità intestinale, l’acalasia esofagea, il laringocele, malformazioni gastrointestinali e urinarie. Anche lesioni mammarie, epatiche e timiche possono causare falsi positivi. Sebbene siano stati segnalati rari falsi positivi da cause vascolari come l’ematoma subdurale e l’aneurisma aortico, il nostro caso presenta caratteristiche peculiari non descritte in precedenza. Il meccanismo alla base della abnorme iodocaptazione è probabilmente riconducibile al rallentato flusso vascolare dell’angioma capillare con ristagno di sangue e persistenza dello 131I nella lesione. Sebbene la iodocaptazione al WBS e la presenza di Tg dosabile in terapia TSH-soppressiva indirizzassero verso una diagnosi di metastasi polmonare, il mancato incremento della Tg dopo stimolo con rh-TSH è in armonia con la diagnosi finale e la più probabile origine della Tg è la persistenza di tessuto tiroideo al livello del dotto tireoglosso, come documentato dal WBS post-dose.
CONCLUSIONI: Il riconoscimento di un falso positivo del WBS è fondamentale per evitare inutili ulteriori terapie con 131I e ansia al paziente. Questo caso ripropone l’importanza di valutare tutti i parametri clinici, biochimici e morfo-funzionali disponibili per il follow-up del DTC allo scopo di formulare una corretta diagnosi ed impostare una adeguata terapia
Salivary glands US examination after radioiodine-131 treatment for differentiated thyroid cancer.
No full textBackground: the most important side effect of radioiodine (131I) therapy is sialoadenitis and xerostomy. Aim: to evaluate by ultrasound (US) parotid and submandibular glands after 131I therapy for differentiated thyroid cancer (DTC). Patients: 76 subjects thyroidectomised for DTC submitted to salivary glands US examination. Forty3 of them had been previously treated with 131I: 22 with 1.11 GBq (30 mCi) for remnant ablation, and 21 with higher doses (up to 44.4 GBq - 1200 mCi) for metastases. 33 subjects were studied before 131I therapy, and were the controls. Parotid and submandibular volume, homogeneity and echogenicity were determined. 131I treated patients filled a questionnaire about sialoadenitis symptoms. Results: Parotid gland volume was significantly higher in treated patients (28.3 ± 16.2 ml) than in untreated patients (20.7 ± 10.4 ml p = 0.0154) and related to the time from last 131I therapy. 3 had parotid volume <1.5 ml and complained severe xerostomy. Submandibular gland volume was similar in treated (11.2 ± 7.6 ml) and untreated patients (8.6 ± 4.2 ml, p = 0.0602). Homogeneity and echogenicity were similar in treated and untreated patients. Sialoadenitis symptoms were reported in 26% and were related to the 131I cumulative dose. Symptoms were not related to gland volume. Hypoechogenicity and inhomogeneity of the parotids were more frequent in patients with salivary stickiness. Conclusion: parotid, but not submandibular, volume is increased after 131I treatment depending on the received activity and the time from irradiation, but not on sialoadenitis symptoms. Xerostomy is associated to gland atrophy at US
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