The investigation of some nutritional requirements of rat embryos undergoing organogenesis in vitro.

Repeated culture of rat conceptuses of between 101/2 and 111/2 days' gestation in the same sample of rat serum showed that the serum has a finite ability to support embryonic growth and development. After four consecutive cultures of rat conceptuses the serum became exhausted and analysis of it showed that rat conceptuses utilized glucose and certain proteins present within the serum. It was also concluded that rat conceptuses secreted toxic dialysable and non-dialysable components into the medium during culture and these materials affected embryonic growth during subsequent culture of conceptuses in exhausted serum. The nutritional value of free amino acids as a substitute for serum proteins was studied by the addition of leupeptin - a specific lysosomal enzyme inhibitor - to the culture serum. The effect of this was partially reversed if free amino acids were included in the leupeptin-containing serum. The inclusion of both essential and non-essential amino acids in the culture medium was found to be necessary for embryonic growth. A model system for further studies of histiotrophic nutrition (the giant yolk sac) was devised by simple modification of New's culture technique to beyond the usual 48 hours thus allowing for maximum growth of the extra-embryonic membranes in vitro. After 7 extra days' culture in rat serum the giant yolk sac was 2 cm. in diameter and contained approximately 600 micro1 yolk sac fluid. The morphology, junctional permeability, histochemistry and endocytic activity of the giant yolk sac showed this system was, in general, similar to the in vivo yolk sac of a comparable gestational age. The giant yolk sac transported radio-labelled free amino acids which accumulated in the yolk sac fluid and analysis of this fluid showed it to contain 14 major proteins; some of these contained radio-labelled amino acids and were, therefore, synthesised by the giant yolk sac. Finally, giant yolk sac fluid was able to improve the nutritional status of exhausted serum and, therefore, contained components which are vital to normal embryonic growth and development. The major feature of the giant yolk sac system is its capacity to produce the products of histiotrophic nutrition in large quantities for biochemical analysis

Licorice: A possible anti-inflammatory and anti-ulcer drug

The purpose of this investigation was to study the anti-inflammatory activities of both glycerrhitinic acid (GA) and the aqueous licorice extract (ALE) in comparison with diclofenac sodium (DS) (10 mg/kg), using the carrageenan-induced paw edema model in male albino rats. In addition, the anti-ulcer activities of ALE, famotidine (FT), and a combination of ALE and FT using indomethacin-induced ulceration technique in rat stomach were investigated. Conventional DS tablets containing GA, as well as DS chewable tablets containing either GA or ALE with different tastes were prepared. Also, rapidly disintegrating FT tablets were prepared using direct compression and camphor sublimation methods. ALE or GA produced significant anti-inflammatory activity similar to DS, and when taken concomitantly, there is no possible antagonism. The anti-ulcer activity of licorice was found to be similar to that of FT in indomethacin-induced ulceration technique in rat stomach. Combination therapy of both FT and licorice showed higher anti-ulcer activity than either of them alone. Generally, tablets containing the crosslinked sodium carboxymethyl cellulose (AcDisol) showed more rapidly disintegrating effect than those including Sodium starch glycolate (Primojel). The oral disintegration was very rapid for all the tested formulations. Also, the amount of FT absorbed from the oral cavity was nearly 9 from 10 mg theoretically present in each formula. It could be concluded that both GA and ALE have anti-inflammatory activity comparable with DS. It may be recommended to add ALE to either FT or diclofinac for more effective anti-inflammatory or anti-ulcer formulations, respectively