Actualities on Nuclear Medicine Applications in Sports Medicine

Aims: This paper aims to address some of the main possible applications of actual Nuclear Medicine Imaging techniques and methodologies in the specific context of Sports Medicine, namely in two critical systems: musculoskeletal and cardiovascular. Discussion: At the musculoskeletal level, bone scintigraphy techniques proved to be a mean of diagnosis of functional orientation and high sensibility compared with other morphological imaging techniques in the detection and temporal evaluation of pathological situations, for instance allowing the acquisition of information of great relevance in athletes with stress fractures. On the other hand, infection/inflammation studies might be of an important added value to characterize specific situations, early diagnose of potential critical issues – so giving opportunity to precise, complete and fast solutions – while allowing the evaluation and eventual optimization of training programs. At cardiovascular system level, Nuclear Medicine had proved to be crucial in differential diagnosis between cardiac hypertrophy secondary to physical activity (the so called "athlete's heart") and hypertrophic cardiomyopathy, in the diagnosis and prognosis of changes in cardiac function in athletes, as well as in direct - and non-invasive - in vivo visualization of sympathetic cardiac innervation, something that seems to take more and more importance nowadays, namely in order to try to avoid sudden death episodes at intense physical effort. Also the clinical application of Positron Emission Tomography (PET) has becoming more and more widely recognized as promising. Conclusions: It has been concluded that Nuclear Medicine can become an important application in Sports Medicine. Its well established capabilities to early detection of processes involving functional properties allied to its high sensibility and the actual technical possibilities (namely those related with hybrid imaging, that allows to add information provided by high resolution morphological imaging techniques, such as CT and/or MRI) make it a powerful diagnostic tool, claiming to be used on an each day higher range of clinical applications related with all levels of sport activities. Since the improvements at equipment characteristics and detection levels allows the use of smaller and smaller doses, so minimizing radiation exposure it is believed by the authors that the increase of the use of NM tools in the Sports Medicine area should be considered.

Image upsampling algorithms applied on Nuclear Medicine: comparision of hqnx and nxSaI algorithms families with two interpolation algorithms - nearest neighbour and bicubic interpolation

Introduction: Image resizing is a normal feature incorporated into the Nuclear Medicine digital imaging. Upsampling is done by manufacturers to adequately fit more the acquired images on the display screen and it is applied when there is a need to increase - or decrease - the total number of pixels. This paper pretends to compare the “hqnx” and the “nxSaI” magnification algorithms with two interpolation algorithms – “nearest neighbor” and “bicubic interpolation” – in the image upsampling operations. Material and Methods: Three distinct Nuclear Medicine images were enlarged 2 and 4 times with the different digital image resizing algorithms (nearest neighbor, bicubic interpolation nxSaI and hqnx). To evaluate the pixel’s changes between the different output images, 3D whole image plot profiles and surface plots were used as an addition to the visual approach in the 4x upsampled images. Results: In the 2x enlarged images the visual differences were not so noteworthy. Although, it was clearly noticed that bicubic interpolation presented the best results. In the 4x enlarged images the differences were significant, with the bicubic interpolated images presenting the best results. Hqnx resized images presented better quality than 4xSaI and nearest neighbor interpolated images, however, its intense “halo effect” affects greatly the definition and boundaries of the image contents. Conclusion: The hqnx and the nxSaI algorithms were designed for images with clear edges and so its use in Nuclear Medicine images is obviously inadequate. Bicubic interpolation seems, from the algorithms studied, the most suitable and its each day wider applications seem to show it, being assumed as a multi-image type efficient algorithm.

Fractional Dynamics of Computer Virus Propagation

We propose a fractional model for computer virus propagation. The model includes the interaction between computers and removable devices. We simulate numerically the model for distinct values of the order of the fractional derivative and for two sets of initial conditions adopted in the literature. We conclude that fractional order systems reveal richer dynamics than the classical integer order counterpart. Therefore, fractional dynamics leads to time responses with super-fast transients and super-slow evolutions towards the steady-state, effects not easily captured by the integer order models.

Cytotoxicity in L929 fibroblasts and inhibition of herpes simplex virus type 1 Kupka by estuarine cyanobacteria extracts

The cyanobacteria are known to be a rich source of metabolites with a variety of biological activities in different biological systems. In the present work, the bioactivity of aqueous and organic (methanolic and hexane) crude extracts of cyanobacteria isolated from estuarine ecosystems was studied using different bioassays. The assessment of DNA damage on the SOS gene repair region of mutant PQ37 strain of Escherichia coli was performed. Antiviral activity was evaluated against influenza virus, HRV-2, CVB3 and HSV-1 viruses using crystal violet dye uptake on HeLa, MDCK and GMK cell lines. Cytotoxicity evaluation was performed with L929 fibroblasts by MTT assay. Of a total of 18 cyanobacterial isolates studied, only the crude methanolic extract of LEGE 06078 proved to be genotoxic (IF > 1.5) in a dose-dependent manner and other four were putative candidates to induce DNA damage. Furthermore, the crude aqueous extract of LEGE 07085 showed anti- herpes type 1 activity (IC50 = 174.10 μg dry extract mL−1) while not presenting any cytotoxic activity against GMK cell lines. Of the 54 cyanobacterial extracts tested, only the crude methanolic and hexane ones showed impair on metabolic activity of L929 fibroblasts after long exposure (48–72 h). The inhibition of HSV-1 and the strong cytotoxicity against L929 cells observed emphasizes the importance of evaluating the impact of those estuarine cyanobacteria on aquatic ecosystem and on human health. The data also point out their potential application in HSV-1 treatment and pharmacological interest.