Application of a Static Fluorescence-based Cytometer (the CellScan) in Basic Cytometric Studies, Clinical Pharmacology, Oncology and Clinical Immunology

The CellScan apparatus is a laser scanning cytometer enabling repetitive fluorescence intensity (FI) and polarization (FP) measurements in living cells, as a means of monitoring lymphocyte activation. The CellScan may serve as a tool for diagnosis of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) as well as other autoimmune diseases by monitoring FP changes in peripheral blood lymphocytes (PBLs) following exposure to autoantigenic stimuli. Changes in FI and FP in atherosclerotic patients' PBLs following exposure to various stimuli have established the role of the immune system in atherosclerotic disease. The CellScan has been evaluated as a diagnostic tool for drug-allergy, based on FP reduction in PBLs following incubation with allergenic drugs. FI and FP changes in cancer cells have been found to be well correlated with the cytotoxic effect of anti-neoplastic drugs. In conclusion, the CellScan has a variety of applications in cell biology, immunology, cancer research and clinical pharmacology

Cryopreservation of cell laden natural origin hydrogels for cartilage regeneration strategies

The time span needed for obtaining a functional cartilage substitute using tissue engineering strategies, together with the need for specific patient oriented constructs has stimulated the growing interest for developing “off-the shelf” products. One way to deliver such products is based on long-term storage processes, such as cryopreservation, that will provide the clinical substitute available as needed and could be adapted to an autologous immediate solution for the patient. The aim of this study was to examine the effects of cryopreservation on the chondrogenic differentiation characteristics of human mesenchymal derived stem cells isolated from adipose tissue and encapsulated in κ-carrageenan hydrogels. These bioengineered constructs are anticipated to participate in a cartilage regeneration strategy providing temporary habitation for cell survival, proliferation and production of an extracellular matrix which is expected to replace the hydrogel, enhancing the regeneration of native tissues in clinical settings. The results obtained show that the hydrogels withstand the cryopreservation with dimethyl sulfoxide, maintaining their structural integrity, while assisting cells proliferation and chondrogenic potential after cryopreservation. Thus, cell encapsulation systems of natural based hydrogels seem to be an interesting approach for the preservation of cartilage tissue engineered products.We acknowledge financial support to the Portuguese Foundation for Science and Technology (FCT) for the PhD grant SFRH/BD/64070/2009 (EP) and to the project MIT-Portugal Program (MIT/ECE/0047/2009)