438 research outputs found

    In HspA from Helicobacter pylori vicinal disulfide bridges are a key determinant of domain B structure

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    Helicobacter pylori produces a heat shock protein A (HspA) that is unique to this bacteria. While the first 91 residues (domain A) of the protein are similar to GroES, the last 26 (domain B) are unique to HspA. Domain B contains eight histidines and four cysteines and was suggested to bind nickel. We have produced HspA and two mutants: Cys94Ala and Cys94Ala/Cys111Ala and identified the disulfide bridge pattern of the protein. We found that the cysteines are engaged in three disulfide bonds: Cys51/Cys53, Cys94/Cys111 and Cys95/Cys112 that result in a unique closed loop structure for the domain

    Management of Barrett’s Esophagus: Practice-Oriented Answers to Clinical Questions

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    Barrett's esophagus is the most important complication of gastro-esophageal reflux disease and the only known precursor of esophageal adenocarcinoma. The diagnosis and treatment of Barrett's esophagus are clinically challenging as it requires a high level of knowledge and competence in upper gastrointestinal endoscopy. For instance, endoscopists should know when and how to perform biopsies when Barrett's esophagus is suspected. Furthermore, the correct identification and treatment of dysplastic Barrett's esophagus is crucial to prevent progression to cancer as well as it is the endoscopic surveillance of treated patients. Herein, we report practice-oriented answers to clinical questions that clinicians should be aware of when approaching patients with Barrett's esophagus

    Dosimetrical evaluation of rotation errors in the patient set-up in lung SBRT treatments

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    EnStereotactic body radiation therapy (SBRT) is a noninvasive, well-tolerated technique in the management of lung malignancies. SBRT requires a high degree of accuracy in target localization and treatment delivery to achieve tumor control while minimizing normal tissue toxicity. Through volumetric imaging, it is possible to obtain comprehensive assessment of patient positioning uncertainties before every treatment delivery. The purpose of this study was to quantify the magnitude of the rotational setup errors in lung SBRT using CBCT and to investigate the dosimetric impact of uncorrected rotational uncertainty. The dosimetric study was conducted on a thorax phantom. The retrospective analysis of CBCT set-up images shows that rotational errors detected in the patient's set-up are on average small in amplitude, although a certain variability index has been observed which can't be considered negligible in the evaluation of the dosimetric impact on the target coverage. The dosimetric study on phantom shows that the effect of uncorrected rotations on target coverage can't always be considered irrelevant and their clinical significance depends on the entity of rotation and target size. In conclusion, the presence of rotations in the positioning of the patient must be carefully investigated before every treatment delivery, especially for small targets size.ItLa stereotassi corporea (SBRT) è una terapia radioterapica non invasiva utilizzata nella cura dei tumori al polmone. SBRT richiede un alto grado di accuratezza nella localizzazione del tumore per ottenere un maggiore controllo della malattia minimizzando la tossicità ai tessuti sani. Mediante l'uso di immagini volumetriche, è possibile valutare gli errori di posizionamento del paziente prima del trattamento. Lo scopo di questo studio è quello di quantificare gli errori rotazionali di set up usando immagini CBCT di pazienti e valutare l'impatto dosimetrico di tali errori simulandoli su un fantoccio antropomorfo. L'analisi retrospettiva delle immagini di set up mostra che gli errori rotazionali rilevati sono in media piccoli in ampiezza, tuttavia l'indice di variabilità osservato può incidere sull'accuratezza della copertura dosimetrica del target. Lo studio dosimetrico sul fantoccio mostra che gli effetti di errori di rotazione dal punto di vista dosimetrico dipendono dalla entità di rotazione e dalle dimensioni del target. L'errore di rotazione dovrebbe essere valutato e corretto prima di ogni trattamento, soprattutto in presenza di lesioni di piccole dimensioni

    Dosimetric verification of vmat dose distribution with DELTA4 Phantom

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    Radiation Oncology, has changed a great deal, undergoing an innovation and technical development; there has been an evolution from conformal radiotherapy techniques (3D-CRT), through advanced modalities like intensity-modulated radiation therapy (IMRT) and next volumetric modulated arc therapy (VMAT). VMAT technique requires a dedicated QA (Quality Assurance) procedure for dosimetric verification of a planned dose distribution to check for the agreement between a dose distribution calculated by the Treatment Planning System (TPS) and the corresponding measured dose distribution. Since November 2010, in Radiation Therapy Department of “V. Fazzi” hospital in Lecce (Italy), 257 patients were treated with VMAT and the corresponding dose distribution were verified with the Delta4 diode array phantom. Parameters used in the comparison between calculated e measured dose are the dose agreement (DA), the distance to agreement (DTA) and the -index. The phantom measurements closely match the planned dose distributions in high and low dose-gradient region

    Diagnostic performance of endoscopic ultrasound-guided tissue acquisition of splenic lesions: systematic review with pooled analysis

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    Background: Focal splenic lesions are usually incidentally discovered on radiological assessments. Although percutaneous tissue acquisition (TA) under trans-abdominal ultrasound guidance is a well-established technique for obtaining cyto-histological diagnosis of focal splenic lesions, endoscopic ultrasound (EUS)-guided TA has been described in several studies, reporting different safety and outcomes. The aim was to assess the pooled safety, adequacy, and accuracy of EUS-TA of splenic lesions. Methods: A comprehensive review of available evidence was conducted at the end of November 2021. All studies including more than five patients and reporting about the safety, adequacy, and accuracy of EUS-TA of the spleen were included. Results: Six studies (62 patients) were identified; all studies have been conducted using fine-needle aspiration (FNA) needles. Pooled specimen adequacy and accuracy of EUS-TA for spleen characterization were 92.8% [95% confidence interval (CI), 86.3%-99.3%] and 88.2% (95% CI, 79.3%-97.1%), respectively. The pooled incidence of adverse events (six studies, 62 patients) was 4.7% (95% CI, 0.4%-9.7%). Conclusion: EUS-FNA of the spleen is a safe technique with high diagnostic adequacy and accuracy. The EUS-guided approach could be considered a valid alternative to the percutaneous approach for spleen TA

    Combination of fecal calprotectin and initial coronary dimensions to predict coronary artery lesions persistence in Kawasaki disease

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    Kawasaki Disease (KD) is systemic vasculitis involving medium-sized vessels in children. The aim of our study is to determine if fecal calprotectin (FC) could be useful in predicting the development or persistence of coronary artery lesions (CALs) in KD. We conducted a prospective monocentric study including all consecutive diagnoses of. Clinical, laboratory, echocardiographic data were recorded during the acute and subacute phase, including FC. Correlations among laboratory values, FC, clinical manifestations, IVIG-responsiveness and CALs development were investigated. We enrolled 26 children (76.9% boys; median age 34.5 months). The combination of FC > 250 microg/g and z-score > 2 during the acute phase was associated with the persistence of CALs (p = 0.022). A z-score > 2 alone during the acute phase was not related to CALs during the subacute stage (p > 0.05). A neutrophil percentage > 70% and WBC > 15,000/mmc during the acute phase significantly correlated with the presence of CALs during the subacute phase (p = 0.008). C-reactive protein (CRP) > 13 mg/dL at KD onset was significantly associated with the presence of CALs during the acute (p = 0.017) and subacute phase (p = 0.001). The combination of FC > 250 microg/g and a z-score > 2 during the acute phase of KD may be used as a predictor of CALs persistence. It can be useful especially in children with an initial CRP < 13 mg/dl

    The crystal structure of S

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