Feasibility of high pressure freezing with freeze substitution after long-term storage in chemical fixatives.

Fixation of biological samples is an important process especially related to histological and ultrastructural studies. Chemical fixation was the primary method of fixing tissue for transmission electron microscopy for many years, as it provides adequate preservation of the morphology of cells and organelles. High pressure freezing (HPF) and freeze substitution (FS) is a newer alternative method that rapidly freezes non-cryoprotected samples that are then slowly heated in the FS medium, allowing penetration of the tissue to insure adequate fixation.

Utilization of cellulose microcapillary tubes as a model system for culturing and viral infection of mammalian cells.

Cryofixation by high-pressure freezing (HPF) and freeze substitution (FS) gives excellent preservation of intracellular membranous structures, ideal for ultrastructural investigations of virus infected cells. Conventional sample preparation methods of tissue cultured cells can however disrupt the association between neighboring cells or of viruses with the plasma membrane, which impacts upon the effectiveness whereby virus release from cells can be studied. We established a system for virus infection and transmission electron microscopy preparation of mammalian cells that allowed optimal visualization of membrane release events.

Expression of the H- and L-subunits of ferritin in bone marrow macrophages of patients with osteoarthritis.

Osteoarthritis is a disease characterized by an increase in the production of reactive oxygen species (ROS) in afflicted joints. Excess iron, due to its role in the production of ROS and crystal deposition in the joints, is implicated in the disease progression of osteoarthritis. Ferritin is a major regulator of the bioavailability of iron, and its functions are determined largely by the combination of H- and L-subunits present in its outer protein shell.