Effect of overall charge and charge distribution on cellular uptake, distribution and phototoxicity of cationic porphyrins in HEp2 cells.

Five cationic porphyrins bearing one to four -N(CH(3))(3)(+) groups linked to the p-phenyl positions of 5,10,15,20-tetraphenylporphyrin (TPP) were synthesized in order to study the effect of overall charge and its distribution on the cellular uptake, phototoxicity and intracellular localization using human carcinoma HEp2 cells. The di-cationic porphyrins DADP-o and DADP-a accumulated the most within cells and preferentially localize within vesicular compartments and in mitochondria. Of these two only DADP-a was phototoxic to the cells (IC(50)=3 microM at 1 J/cm(2)).

Synthesis of deoxytetrahydrouridine.

The alpha-hydroxyamido functionality of 2'-deoxytetrahydrouridine (dTHU) makes this seemingly simple and generally useful compound difficult to obtain. Reported synthetic strategies produce extremely poor yields and multiple products, and full characterization data is not available. Described herein is a two-step approach for synthesizing dTHU in increased yields and purity; stability concerns are also addressed.

Stability of cultured dental follicle cells.

Because the dental follicle is required for tooth eruption, establishment of dental follicle cell (DFC) lines is needed for experimentation to determine how the cells regulate eruption. Thus, it is critical that the follicle cells in culture remain stable and neither become transformed nor differentiate. To determine the stability of rat DFC cultures in terms of exhibiting contact inhibition of growth when confluent (no transformation), DFC at different passages were analysed using flow cytometry.