Technical library

"Adult stem cells" are stem cells isolated from postnatal tissues that have retained the capacity for cell renewal as well as for differentiation into multiple lineages (multipotency).

PromoCell does not determine the number of passages but instead we calculate the population doublings (PD) that can be performed with the cells. The term passage only describes the process of detachment and replating and does not take into account different split ratios. The optimal split ratio is calculated from the actual cell yield after trypsinisation and the recommended plating density. In most of our cell types, the split ratio is usually between 1:3 and 1:6. Using 1:4 splits (i.e. increasing the growth surface by factor 4 each time), 15 doublings are achieved after 6-8 passages. For recommended plating densities, please view the respective Manual, section "Specifications".

We guarantee 15 population doublings (PD) for most Normal Human Cells (unless otherwise indicated in the Certificate of Analysis), when the recommended PromoCell media and the detachment reagents are used.

Further information can be found in the respective Product Manual under "Specifications".

Please find attached a trouble shooting guide to identify possible reasons for poor detachment during subculture.

Microbiological contaminations can be introduced into cell cultures by unsterile working techniques, contaminated water baths, media, plasticware, etc. Please check the attached trouble shooting guide for more detailed information.

Your observation can be either ascribed to a change of the culture medium, to a cross-contamination with another cell type, or to differentiation or senescence. The attached trouble shooting guide should help you to identify the reason for your observation.

Normal cells have a finite life span and therefore eventually stop growing and become senescent. In addition, a cease in proliferation or cell death can be induced by other factors. For more details, check the trouble shooting guide below.

In principle, all microvascular endothelial cells should be able to migrate, proliferate and form tubes or sprouts in an appropriate assay after angiogenic stimulation. As this is not part of our routine quality control procedure, we cannot tell for sure whether all cell lots will respond to angiogenic stimuli. However PromoCell also supplies HDMEC pre-screened (C-12215) that are especially tested for a positive VEGF response.

No, we don't determine the ratio of HDLEC and HDBEC in our HDMEC lots. From our experience, the percentage of HDLEC is highly lot-dependent and can vary between 5 and 60%.

Our HDMEC are isolated from the dermis of juvenile foreskin or adult skin. The purity is > 95%. Since the dermis contains blood and lymphatic capillaries, HDMEC cultures comprise blood and lymphatic microvascular endothelial cells that have differing morphologies. Both cell types have a common origin and can be identified by several markers. The ratio of lymphatic and blood derived endothelial cells can vary from lot to lot and is not determined at PromoCell.