Pathogenesis of cerebral malaria

Plasmodium knowlesi infected rhesus monkeys were employed for investigating brain tissue damage in experimentally induced cerebral malaria. Light microscopic studies revealed parasitic infiltration of virtually all the regions of CNS. Electron microscopic observations confirmed the light microscopic findings. These studies further revealed the presence of macrophages in the blood vessels of infected monkeys. In conclusion, the pathogenesis of cerebral malaria seems to be an outcome of a typical triad consisting of: (1) mechanical obstruction of the blood capillaries by parasitized RBCs; (2) biochemical events, involving free radicals, and (3) immunological dysfunction.     

Pathogenesis of Dermatophytosis

Despite the superficial localization of most dermatophytosis, host-fungus relationship in these infections is complex and still poorly elucidated. Though many efforts have been accomplished to characterize secreted dermatophytic proteases at the molecular level, only punctual insights have been afforded into other aspects of the pathogenesis of dermatophytosis, such as fungal adhesion, regulation of gene expression during the infection process, and immunomodulation by fungal factors. However, new genetic tools were recently developed, allowing a more rapid and high-throughput functional investigation of dermatophyte genes and the identification of new putative virulence factors. In addition, sophisticated in vitro infection models are now used and will open the way to a more comprehensive view of the interactions between these fungi and host epidermal cells, especially keratinocytes.     

Pathogenesis of Scedosporium

Invasive scedosporiosis is a severe fungal infection, caused by species of the genus Scedosporium (Pseudallescheria teleomorph), usually refractory to treatment and with a common fatal outcome. Although the pathogenesis mechanisms involved in these infections are poorly known some progress has been made in recent years. This paper revises the available data on the experimental virulence and in the identification of virulence factors determinants, as well as the role of the host immune response in the control of the infection. In addition, the basic conditions needed for the invasion and dissemination of Scedosporium in the human body are described and discussed.     

Pathogenesis of Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown etiology. The organs that are involved by sarcoidosis include the lungs in which the granuloma is seen in more than 90% of patients to the pituitary, which is only rarely affected. There are many hypotheses as to the cause of sarcoidosis. Some of them rely on the similarities seen between sarcoidosis and the other granuloma-forming diseases such as tuberculosis, berylliosis, pine pollen inhalation and acute and chronic bacterial and viral infections, while others find similarities between sarcoidosis and immune reactions observed in autoimmune disorders. Still other explanations implicate a genetic predisposition or a still-unknown agent as the underlying cause of the granuloma formation.