Despite the considerable progress that has recently been made in medicine, the treatment of viral infections is still a problem remaining to be solved. This especially concerns infections caused by newly emerging patogenes such as: human immunodeficiency virus, hepatitis C virus or SARS-coronavirus. There are several lines of evidence that the unusual genetic polymorphism of these viruses is responsible for the observed therapeutic difficulties. In order to determine whether some parameters describing a very complex and variable viral population can be used as prognostic factors during antiviral treatment computational methods were applied. To this end, the structure of the viral population and virus evolution in the organisms of two patients suffering from chronic hepatitis C were analyzed. Here we demonstrated that phylogenetic trees and Hamming distances best reflect the differences between virus populations present in the organisms of patients who responded positively and negatively to the applied therapy. Interestingly, the obtained results suggest that based on the elaborated method of virus population analysis one can predict the final outcome of the treatment even before it has started.
The analysis of mechanical behaviour of spinal column is until now still a challenge, in spite of the great amount of research which has been conducted over the last years. It is a particularly complex structure considering number of components, their shapes and mechanical characteristics. The objectives of the presented investigations are to understand the mechanisms of the mechanical behaviour of the spine structure and the role of its components, as well as the factors of its dysfunctions as scoliosis discopathy, spondylolisthesis. Also some mechanical effects of surgical interventions by total disc replacement is considered. To account for the 3D character of the spine system including vertebrae, discs, ligaments, muscles etc. the finite element method (FEM) formulation was used throughout the paper. Some specific features of the structure are included in the models as non-conservative loads and muscular tension control performed by the nervous system. The finite element method together with CAD programs and experimental validation was used in investigations of a new type of artificial disc for lumbar spine. The stress analyses were performed for the prostheses being in clinical use and for some original new designs. The conclusions concern most important determinants of the mechanical behaviour of the system and the quality of the intervertebral disc prosthesis.