109 research outputs found
Design, simulation, and fabrication of a three-dimensional printed pump mimicking the left ventricle motion
The development of accurate replicas of the circulatory and cardiac system is fundamental for a deeper understanding of cardiovascular diseases and the testing of new devices. Although numerous works concerning mock circulatory loops are present in the current state of the art, still some limitations are present. In particular, a pumping system able to reproduce the left ventricle motion and completely compatible with the magnetic resonance environment to permit the four-dimensional flow monitoring is still missing. The aim of this work was to evaluate the feasibility of an actuator suitable for cardiovascular mock circuits. Particular attention was given to the ability to mimic the left ventricle dynamics including both compression and twisting with the magnetic resonance compatibility. In our study, a left ventricle model to be actuated through vacuum was designed. The realization of the system was evaluated with finite element analysis of different design solutions. After the in silico evaluation phase, the most suitable design in terms of physiological values reproduction was fabricated through three-dimensional printing for in vitro validation. A pneumatic experimental setup was developed to evaluate the pump performances in terms of actuation, in particular ventricle radial and longitudinal displacement, twist rotation, and ejection fraction. The study demonstrated the feasibility of a custom pneumatic pump for mock circulatory loops able to reproduce the physiological ventricle movement and completely suitable for the magnetic resonance environment
How early can myocardial iron overload occur in Beta thalassemia major?
BACKGROUND: Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM.
METHODS AND RESULTS: We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients ≤10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload.
CONCLUSIONS: The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old
Joining participatory approach and spatially-based modelling tools for groundwater resource management.
Although a lot of science has been produced on Water Resource Management (WRM) in the Information and
Communication Technology (ICT) sector, WRM is still poorly addressed via scientific means. Some reasons for
this may be: the underrated importance given to this topic at political and decision-making level; the low-capacity
of the research environment to transfer results; and missing numerical modelling capacities at agencies and
governing authorities.
ICT may provide tools for water planning and management, as discussed within the ICT4WATER cluster initiative.
Among these, GIS-integrated numerical modeling is a robust method to represent hydrological systems and to
provide answers to problems of protection of groundwater resources. Because these tools require a high level
of knowledge pertaining to various disciplines, they are often disregarded as complex “tricky games” providing
unrealistic results. This is a barrier to the uptake of technologies for water management.
To overcome this issue, the application of ICT tools has been combined with an innovative participatory approach,
and large capacity building activities, in the framework of the H2020 FREEWAT project (FREE and open source
software tools for WATer resource management; www.freewat.eu). The major result of the project consists in an
open source and public domain, QGIS-integrated modeling platform for promoting WRM.
FREEWAT capabilities have been demonstrated at 14 case studies in EU and non-EU Countries, where the
effectiveness of few measures foreseen in River Basin Management Plans for achieving good status of water
bodies was tested.
At each case study, a Focus Group (FG) participated by local stakeholders (e.g., river basin authorities, research
institutions, environmental protection agencies, environmental associations) was formed and seven meetings were
organized. During these meetings, the objective of each case study, the methodology to be adopted, including
definition of the conceptual model and of data needed, were discussed. The FG also took decisions on scenarios
to be simulated for testing the feasibility of the foreseen measures. FGs aimed at demonstrating that WRM may
be performed with open source and public domain software and participants’ perception on using ICT tools for
WRM was discussed.
Some of the implemented models are now being used for operational purposes: Vrbansky plato (Slovenia),
where FREEWAT is used to monitor remediation of heating oil spillage and the water supply company intends to
maintain and use developed groundwater flow model for managed groundwater recharge with induced riverbank
filtration; the Bremerhaven case study (Germany), where the local water authority intends to use the developed
groundwater flow model for predictions; the Scarlino-Follonica case study (Italy), where the model will be used by
the regional authority to manage private groundwater remediation projects in a large industrial contaminated site;
the Gozo case study (Malta), where the model is being developed to support the assessment of good groundwater
quantitative status as part of the implementation of the Water Framework Directive
Lithium suppression of tau induces brain iron accumulation and neurodegeneration
Lithium is a first-line therapy for bipolar affective disorder. However, various adverse effects, including a Parkinson-like hand tremor, often limit its use. The understanding of the neurobiological basis of these side effects is still very limited. Nigral iron elevation is also a feature of Parkinsonian degeneration that may be related to soluble tau reduction. We found that magnetic resonance imaging T2 relaxation time changes in subjects commenced on lithium therapy were consistent with iron elevation. In mice, lithium treatment lowers brain tau levels and increases nigral and cortical iron elevation that is closely associated with neurodegeneration, cognitive loss and parkinsonian features. In neuronal cultures lithium attenuates iron efflux by lowering tau protein that traffics amyloid precursor protein to facilitate iron efflux. Thus, tau- and amyloid protein precursor-knockout mice were protected against lithium-induced iron elevation and neurotoxicity. These findings challenge the appropriateness of lithium as a potential treatment for disorders where brain iron is elevated (for example, Alzheimer’s disease), and may explain lithium-associated motor symptoms in susceptible patients
Reducing pain in children with cancer: Methodology for the development of a clinical practice guideline
Abstract
Although pain is one of the most prevalent and bothersome symptoms children with cancer
experience, evidence-based guidance regarding assessment and management is lacking. With
44 international, multidisciplinary healthcare professionals and nine patient representatives, we
aimed to develop a clinical practice guideline (following GRADE methodology), addressing assessment and pharmacological, psychological, and physical management of tumor-, treatment-, and procedure-related pain in children with cancer. In this paper, we present our thorough methodology for this development, including the challenges we faced and how we approached these. This
lays the foundation for our clinical practice guideline, for which there is a high clinical demand
A fast and effective method to assess myocardial necrosis by means of contrast magnetic resonance imaging RID A-6953-2008
Purpose. Contrast magnetic resonance (CMR) can identify myocardial necrosis after gadolinium administration as a hyperenhanced ( HE) area. Yet there are no software tools that can effectively quantify such an area. The aim of this study is to develop a robust and effective algorithmic method for defining the extent of myocardial necrosis evidenced through CMR. Method. Fifteen patients with previous myocardial infarction underwent nitrate Tetrofosmin G-SPECT and CMR. A software tool was developed, allowing semiautomatic detection of endocardial and epicardial borders and the automatic detection of HE regions. The accuracy of the proposed quantitative method of analysis has been tested with G-SPECT analysis that it is less than an ideal method for assessing myocardial viability, but at present is accepted and widely used in the clinical arena. Results. Segmental (SEHE) and global extension of HE were evaluated. HE was present in 161 of the 255 analyzed segments. Of the 161 HE segments, the mean SEHE was 36 +/- 30%. The operator independence (intraobserver: r = 0.97, p < 0.0001, interobserver: r = 0.95, p < 0.0001) was good and significant, with noticeable time savings with respect to manual analysis. There was strong and inverse correlation between SEHE and scintigraphic regional uptake reduction ( r = - 0.66, p < 0.0001), and also a positive correlation between SEHE and SPECT defect extension ( r = 0.75, p < 0.0001). When assessing the global extent of necrosis, the correlation between the two techniques was strong ( r = 0.79, p = 0.0004). Conclusions. The proposed method of quantifying myocardial necrosis by CMR is highly reliable, reproducible, and operator-independent for quantifying
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