49 research outputs found
Ultrasound imaging classifications of thyroid nodules for malignancy risk stratification and clinical management : state of the art
Assessing the risk of malignancy in the thyroid with ultrasound (US) is crucial in patients with nodules, as it can aid in selecting those who should have a fine-needle aspiration (FNA) biopsy performed. Many studies have examined whether the US characteristics of thyroid nodules are useful indicators of histological malignancy. Overall, these investigations have identified a few US features that are significantly more frequent in malignant thyroid nodules which can be coalesced into a defining set to be used as an indicator of a higher risk of malignancy. Despite these efforts, none of these classifications have been widely adopted worldwide, and there are still conflicting recommendations from different institutions. Understanding the role and appropriate utilization of these systems could facilitate the effective interpretation and communication of thyroid US findings among referring physicians and radiologists. In this comprehensive review, we outline the major US classification systems of thyroid nodules published in the last few years
Thermoluminescent dosimeters (TLDs-100) calibration for dose verification in photon and proton radiation therapy
Thermoluminescent dosimeters (TLDs) are practical, accurate, and precise tools for point dosimetry in medical physics applications. TLDs are nowadays extensively used to measure dose in conformal radiation therapy in order to
guarantee the safety of the treatment. Several national and international organizations recommend checking the effective dose delivered to an individual patient by means of in vivo dosimetry. Modern radiotherapy techniques employing both photon and ion beams exhibit excellent target conformation throught high steep-dose gradients between tumour and adjacent organs and tissues. In this context, catching potential dose errors and uncertainties in treatment delivering is the first step to ensure the optimization of the treatment plan. This study shows the results of the characterization of TLDs-100 at two Italian facilities devoted to advanced radiation treatments with photon and proton therapy. The individual sensitivity factor was determined, and the calibration curves were carried out in the dose range 0–20 Gy. By the analysis of the dose response curves, the linear region was identified under the dose level of 10 Gy. Characterization of the TLDs-100 has enabled their use for in vivo dosimetry especially in the dose range corresponding to the linear region of the dose response curves
Cohesin promotes the repair of ionizing radiation-induced DNA double-strand breaks in replicated chromatin.
The cohesin protein complex holds sister chromatids together after synthesis until mitosis. It also contributes to post-replicative DNA repair in yeast and higher eukaryotes and accumulates at sites of laser-induced damage in human cells. Our goal was to determine whether the cohesin subunits SMC1 and Rad21 contribute to DNA double-strand break repair in X-irradiated human cells in the G2 phase of the cell cycle. RNA interference-mediated depletion of SMC1 sensitized HeLa cells to X-rays. Repair of radiation-induced DNA double-strand breaks, measured by gammaH2AX/53BP1 foci analysis, was slower in SMC1- or Rad21-depleted cells than in controls in G2 but not in G1. Inhibition of the DNA damage kinase DNA-PK, but not ATM, further inhibited foci loss in cohesin-depleted cells in G2. SMC1 depletion had no effect on DNA single-strand break repair in either G1 or late S/G2. Rad21 and SMC1 were recruited to sites of X-ray-induced DNA damage in G2-phase cells, but not in G1, and only when DNA damage was concentrated in subnuclear stripes, generated by partially shielded ultrasoft X-rays. Our results suggest that the cohesin complex contributes to cell survival by promoting the repair of radiation-induced DNA double-strand breaks in G2-phase cells in an ATM-dependent pathway
Different modalities of classification and prognostic significance of ventricular arrhythmias after acute myocardial infarct. Prospective study [Differenti modalitá di classificazione e significato prognostico delle aritmie ventricolari dopo infarto acuto del miocardio. Studio prospettivo.]
In our study we compared the prognostic significance of clinical variables, laboratory results and different classification models of ventricular ectopic beats recorded by means of a pre-discharge 24 hour ambulatory electrocardiographic monitoring, in 210 survivors of acute myocardial infarction. In addition a full multivariate analysis of the factors affecting survival time was carried out using Cox's proportional hazards (multiple) regression model. Multivariate stepwise discriminant analysis identified hypertension, congestive heart failure assessed by Killip class, and the grading system for ventricular arrhythmias as the most important prognostic variables. When Moss grading system for ventricular arrhythmias was used, the relative risk was a superior as heavy Moss grading system (Moss 2 vs Moss 1 and Moss 3-4 vs Moss 1, relative risk = 1.2 and 3.6 total death, respectively). Furthermore, the hazard ratio of Moss grading system was higher utilizing as comparison patients without ventricular ectopic beats (relative risk = 1.7 for Moss 2 and 5.3 for Moss 3-4) than patients with ventricular ectopic beats less than one/hour (relative risk = 1.2 for Moss 2 and 3.7 for Moss 3-4). Thus, in survivors of acute myocardial infarction, a rational and useful ventricular ectopic beats categorization includes both frequency and the presence or absence of malignant characteristics
Prognostic evaluation of patients surviving acute myocardial infarct: univariate and multivariate analysis [Valutazione prognostica dei pazienti sopravvissuti ad infarto acuto del miocardio: analisi uni e multivariata.]
The relationship between 31 variables and survival after acute myocardial infarction was evaluated in 432 patients discharged from our Coronary Care Unit from 1975 to 1984. The patients were followed for 1 to 105 months and either univariate and multivariate analysis were performed. For end-point death the significant variables (p less than 0.05) selected by the univariate analysis were: age, diabetes, smoke, heart rate at recovery, supraventricular arrhythmias, cardiac failure and complex ventricular arrhythmias either during recovery, either after discharge and finally spontaneous angina after hospital discharge. Meanwhile, for the end-point cardiac death age, smoke and supraventricular arrhythmias were not yet significant while arterial pressure at recovery and effort angina after hospital discharge were. Multivariate analysis identified cardiac failure during recovery, diabetes, complex ventricular arrhythmias before and spontaneous angina after discharge as independent variables contributing to total mortality: effort angina was a further significant one relatively to cardiac death. Thus, our study points out the importance of multivariate survival analysis when evaluating the relationship between survival after discharge for the effect of other prognostic factors. Moreover, providing identification of high risk cohorts permits appropriate interventions designed to lessen risk