Caco-2 cell acquisition of dietary iron(III) invokes a nanoparticulate endocytic pathway

Dietary non-heme iron contains ferrous [Fe(II)] and ferric [Fe(III)] iron fractions and the latter should hydrolyze, forming Fe(III) oxo-hydroxide particles, on passing from the acidic stomach to less acidic duodenum. Using conditions to mimic the in vivo hydrolytic environment we confirmed the formation of nanodisperse fine ferrihydrite- like particles. Synthetic analogues of these (~ 10 nm hydrodynamic diameter) were readily adherent to the cell membrane of differentiated Caco-2 cells and internalization was visualized using transmission electron microscopy. Moreover, Caco-2 exposure to these nanoparticles led to ferritin formation (i.e., iron utilization) by the cells, which, unlike for soluble forms of iron, was reduced ( p =0.02) by inhibition of clathrin-mediated endocytosis. Simulated lysosomal digestion indicated that the nanoparticles are readily dissolved under mildly acidic conditions with the lysosomal ligand, citrate. This was confirmed in cell culture as monensin inhibited Caco-2 utilization of iron from this source in a dose dependent fashion ( p <0.05) whilet soluble iron was again unaffected. Our findings reveal the possibility of an endocytic pathway for acquisition of dietary Fe(III) by the small intestinal epithelium, which would complement the established DMT-1 pathway for soluble Fe(II

HB 467, Relating to the Fish and Wildlife Advisory Committees - Statement for House Committee Water, Land Use Development and Hawaiian Affairs Public Hearing, 23 February 1981

info:eu-repo/semantics/publishe

Do investors value the FDA orphan drug designation?

Abstract Background The Orphan Drug Act is an important piece of legislation that uses financial incentives to encourage the development of drugs that treat rare diseases. This analysis studies the effects of a portion of the Orphan Drug Act, the orphan drug designation. Specifically, it studies the value that investors place on the orphan drug designation, by investigating how investors react to companies’ announcing that their product has received the designation. Results The results, on average, show that the stock price of a company increases by 3.36% after the announcement of the designation, increasing the value of the company. The results are more pronounced for oncology drugs, and drugs being developed by the smallest companies. Conclusion The orphan designation appears to be successful at generating positive value for companies, as seen by the positive and significant average increases in stock price