Regulatory practices and problems with vaccine stability studies and the establishment of shelf lives.

Current international regulatory documents do not provide guidance on how the data from stability studies should be used in the establishment of shelf lives. As an example, for live virus vaccines no limits have been considered for acceptable losses of potency during storage. Providing that the specifications stated on the label are maintained significant inactivation rates are compatible with regulations.

The heteromorphology of cultured microvascular endothelial cells.

Endothelial cells alter morphology easily when culture conditions change. One has omitted to test carefully whether this heteromorphology represents constitutional differences which are maintained in culture. Cells were isolated from the microvascular tree of the bovine corpus luteum by mechanical disintegration, i.

Bovine microvascular endothelial cells of separate morphology differ in growth and response to the action of interferon-gamma.

Five cell types recently isolated from the bovine corpus luteum differed in their epithelioid morphology and their cytoskeleton, but shared common criteria of microvascular endothelial cells. To give strong evidence for the separate entity, the growth rate of the 5 phenotypically different cells was studied. They were seeded at low density on day 0.

Cultured microvascular endothelial cells (MVEC) differ in cytoskeleton, expression of cadherins and fibronectin matrix. A study under the influence of interferon-gamma.

Endothelial cells are known to undergo transitions in cell shape during long-term culture. Thus, the assumption that the separate phenotypes of microvascular endothelial cells (MVEC) recently isolated from bovine corpus luteum represent constitutively different cell strains cannot automatically be made. For this reason, particular morphological qualities from four of five reported MVEC types were studied.