The relationship between tissue levels of flavone acetic acid (NSC 347512) and site dependent anti-tumour activity in murine colon tumours.

Flavone acetic acid (FAA) is extremely active against subcutaneous transplantable tumours in mice, but disappointingly there has been no demonstrable clinical activity. Previous studies have shown that lung tumour deposits are less responsive than the same cells implanted subcutaneously. The aim of this study is to examine the tissue disposition of FAA in an attempt to explain this site-dependent activity. The data show clearly that FAA clearance curves are influenced by the presence of MAC 15A tumours growing either subcutaneously or systemically. The decreased clearance of FAA from MAC 15A tumour bearing animals does not however explain the resistance of lung deposits. Neither can this be explained by differences in metabolism in these different sites. Cytotoxic metabolites have not been detected either in vitro or in vivo and their role in the mechanism of action of FAA is questionable

Microstructural Characterization of Graphite Spheroids in Ductile Iron

The present work brings new insights by transmission electron microscopy allowing disregarding or supporting some of the models proposed for spheroidal growth of graphite in cast irons. Nodules consist of sectors made of graphite plates elongated along a hai direction and stack on each other with their c axis aligned with the radial direction. These plates are the elementary units for spheroidal growth and a calculation supports the idea that new units continuously nucleate at the ledge between sectors

Factors involved in the anti-cancer activity of the investigational agents LM985 (flavone acetic acid ester) and LM975 (flavone acetic acid).

LM985 has been shown previously to hydrolyse to flavone acetic acid (LM975) in mouse plasma and to produce significant anti-tumour effects in transplantable mouse colon tumours (MAC). It has undergone Phase I clinical trials and dose limiting toxicity was acute reversible hypotension. Substantially higher doses of LM975 can be given clinically without dose limiting toxicity. We have investigated the activity of LM975 against a panel of MAC tumours and also the in vitro cytotoxicity of both LM985 and LM975 in two cell lines derived from MAC tumours. LM985 is considerably more cytotoxic than LM975 in vitro but increased length of exposure to LM975 results in improved activity. Single in vivo injection of LM975 showed no activity against the ascitic tumour MAC 15A, moderate activity against the s.c. poorly differentiated tumour MAC 13 and produced a significant growth delay in the well differentiated MAC 26. These latter responses were considerably enhanced by repeated injection 7 days later. Pharmacokinetic studies in mice following i.p. injection of LM985 demonstrated rapid degradation of LM985 to LM975 in the peritoneum. Length of exposure as well as drug concentration appear important factors in determining anti-tumour responses