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Purpose: To present the impact in coverage of different methods for Poisson confidence intervals and the impact in dose coverage of different uncertainty factors. A detailed explanation of the uncertainty sources in the Bayesian method is also presented. Materials and methods: The exact coverage of uncertainty Poisson confidence intervals and the dose uncertainty interval coverage were performed by simulations using R-based scripts. Results: The Poisson exact calibration interval via the Modified Crow and Gardner method resulted in coverage quite close to the nominal level of confidence; additionally, the method retains the shortest property of Crow and Gardner, and gains the property of a lower limit strictly increasing in the mean of dicentrics. The unlimited simultaneous calibration interval seems to be the method of choice to preserve the coverage at 95% under parametric and nonparametric conditions but is a conservative method. When samples came from a Poisson distribution, the ISO propagation of errors and Bayesian approaches seem to be the closest to the 95% coverage. Conclusions: The Modified Crow and Gardner method should be preferred over the Garwood method for Poisson exact confidence intervals. The unlimited simultaneous calibration interval did not lose its property to preserve the coverage at 95% applying a regression coverage factor of value 2.02 at the point of doses studied in the simulation. [ABSTRACT FROM AUTHOR]

High levels of scatter radiation in catheterization laboratories may lead to posterior subcapsular opacities in the lens of the staff. The international Retrospective Evaluation of Lens Injuries and Dose (RELID) was performed in Argentina for the first time in 2010 in the context of the congress of the Latin American Society of Interventional Cardiology (SOLACI) and recently, in 2014, was carried out for the second time (SOLACI-CACI 2014). The 2014 study included 115 participants: interventional cardiologists, technicians and nurses. Posterior subcapsular lens changes typical of ionizing radiation exposure were found in 91.5% of interventional cardiologists, in 77% of technicians and in 100% of nurses, according to the Merriam-Focht scale. This RELID study (Argentina 2014) has particular importance since it allowed the follow-up of 10 professionals evaluated in 2010. The results obtained in the study population highlight the importance of the availability and proper use of the elements of radiation protection, as well as staff training. [ABSTRACT FROM AUTHOR]

Acute and late radiation-induced injury on skin and subcutaneous tissues are associated with substantial morbidity in radiation therapy, interventional procedures and also are of concern in the context of nuclear or radiological accidents. Pathogenesis is initiated by depletion of acutely responding epithelial tissues and damage to vascular endothelial microvessels. Efforts for medical management of severe radiation-induced lesions have been made. Nevertheless, the development of strategies to promote wound healing, including stem cell therapy, is required. From 1997 to 2014, over 248 patients were referred to the Radiopathology Committee of Hospital de Quemados del Gobierno de la Ciudad de Buenos Aires (Burns Hospital) for the diagnosis and therapy of radiation-induced localized lesions. As part of the strategies for the management of severe cases, there is an ongoing research and development protocol on 'Translational Clinical Trial phases I/II to evaluate the safety and efficacy of adult mesenchymal stem cells from bone marrow for the treatment of large burns and radiological lesions'. The object of this work was to describe the actions carried out by the Radiopathology Committee of the Burns Hospital in a chronic case with more than 30 years of evolution without positive response to conventional treatments. The approach involved the evaluation of the tissular compromise of the lesion, the prognosis and the personalized treatment, including regenerative therapy. [ABSTRACT FROM AUTHOR]

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included. [ABSTRACT FROM AUTHOR]

The bottleneck in data acquisition during biological dosimetry based on a dicentric assay is the need to score dicentrics in a large number of lymphocytes. One way to increase the capacity of a given laboratory is to use the ability of skilled operators from other laboratories. This can be done using image analysis systems and distributing images all around the world. Two exercises were conducted to test the efficiency of such an approach involving 10 laboratories. During the first exercise (E1), the participant laboratories analysed the same images derived from cells exposed to 0.5 and 3 Gy; 100 images were sent to all participants for both doses. Whatever the dose, only about half of the cells were complete with well-spread metaphases suitable for analysis. A coefficient of variation (CV) on the standard deviation of ∼15 % was obtained for both doses. The trueness was better for 3 Gy (0.6 %) than for 0.5 Gy (37.8 %). The number of estimated doses classified as satisfactory according to the z-score was 3 at 0.5 Gy and 8 at 3 Gy for 10 dose estimations. In the second exercise, an emergency situation was tested, each laboratory was required to score a different set of 50 images in 2 d extracted from 500 downloaded images derived from cells exposed to 0.5 Gy. Then the remaining 450 images had to be scored within a week. Using 50 different images, the CV on the estimated doses (79.2 %) was not as good as in E1, probably associated to a lower number of cells analysed (50 vs. 100) or from the fact that laboratories analysed a different set of images. The trueness for the dose was better after scoring 500 cells (22.5 %) than after 50 cells (26.8 %). For the 10 dose estimations, the number of doses classified as satisfactory according to the z-score was 9, for both 50 and 500 cells. Overall, the results obtained support the feasibility of networking using electronically transmitted images. However, before its implementation some issues should be elucidated, such as the number and resolution of the images to be sent, and the harmonisation of the scoring criteria. Additionally, a global website able to be used for the different regional networks, like Share Points, will be desirable to facilitate worldwide communication. [ABSTRACT FROM AUTHOR]

According to some studies, 80% of subjects suffering from post-traumatic stress disorder (PTSD) present twice the risk of developing an insanity as they age because of the high level of stress that has been induced. Indeed, the triggered trauma has a deleterious effect on the establishment of the stress’ axis (the hypothalamic pituitary adrenal axis) which is then not able to regulate itself. As a consequence, the hippocampal neurons will be attacked by an excess of cortisol. Memory's dysfunction is central in the symptomatology of PTSD, particularly in respect to encoding and recall. The hippocampus is able to transfer information to the prefrontal cortex. Actually, subjects with PTSD present less activity in the prefrontal cortex triggered by a decrease of encoding and recall capacities. EMDR therapy (eye movement desensitization and recruitment) allow for a fast relief of symptoms by a bilateral alternate stimulation (SBA). Indeed, saccadic eye movements stem affect related to the traumatic event and process the associated cognitions. During the desensitization phase in EMDR, we noticed an increase in activity of the brain's prefrontal, ventromedial, amygdala and thalamic regions. Indeed, the recall of traumatic memories goes through implicit emotional valence regions and associative areas for which the experience is already deeply integrated. After comparing cerebral activity before and after the therapy, researches on EMDR shows that a reduction of stress’ symptoms has some sensitive link to PTSD (in prevention to dementia). [ABSTRACT FROM AUTHOR]

The main objective of the study was the evaluation of the efficacy and homogeneity with which the laboratories of the region carry out biological dosimetry using the two most useful at the present time cytogenetic indicators: the frequency of dicentrics (dicentrics and rings) and that of micronuclei in human lymphocytes. The intercomparison was carried out from codes slides. The gamma radiation doses employed were 0.7,5, 1.5 and 3 Gy. One sample was not irradiated. In the ± 30% of the true dose interval were included 11 out of 15 doses calculated by dicentrics frequency and 9 out of 12 doses calculated by micronuclei frequency. The true doses were in the interval established with 95% confidence limit in 10 out of 12 dose intervals estimated by micronuclei frequency and in 9 out of 15 dose intervals estimated by dicentrics frequency. The laboratory results were similar. [ABSTRACT FROM AUTHOR]

Purpose Transcranial electric stimulations (tES) with amplitude-modulated currents are promising tools to enhance neuromodulation effects. It is essential to select the correct cortical targets and inhibitory/excitatory protocols to reverse changes in specific networks. We aimed at assessing the dependence of cortical excitability changes on the current amplitude of 20 Hz transcranial alternating current stimulation (tACS) over the bilateral primary motor cortex. Methods We chose two amplitude ranges of the stimulations, around 25 μ A/cm2 and 63 μ A/cm2 from peak to peak, with three values (at steps of about 2.5%) around each, to generate, respectively, inhibitory and excitatory effects of the primary motor cortex. We checked such changes online through transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs). Results Cortical excitability changes depended upon current density (p=.001). Low current densities decreased MEP amplitudes (inhibition) while high current densities increased them (excitation). Conclusions tACS targeting bilateral homologous cortical areas can induce online inhibition or excitation as a function of the current density. [ABSTRACT FROM AUTHOR]