Conservation of propane on an IL343 flame photometer attached to a Vickers M300 multichannel discrete analyser.
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Biomedical subjects
Publications and source records attributed to J F Stevens.
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From aerial parts of the fern Pteris multifida Poir. (Polypodiaceae) two diterpenes, entkaurane-2 beta, 16 alpha-diol and ent-kaur-16-ene-2 beta, 15 alpha-diol, were isolated by repeated column chromatography using silica gel and silica gel impregnated with silver nitrate. The structures were confirmed by spectroscopic methods. Both compounds showed a moderate cytotoxicity to Ehrlich ascites tumour cells.
A new flavonoid, 2,3-trans-5,2'-dihydroxy-7,8-dimethoxy-dihydroflavonol-3-O-acetate, was isolated from the farinose coating on the lower leave surface of the fern, Notholaena sulphurea. The 2,3-cis diastereoisomer was isolated as a co-constituent. This novel acylated flavonoid is characteristic for the chemotype of N. sulphurea exhibiting yellow frond exudate. Its orrurrence underlines the affiliation of the species with the genus Notholaena.
Carcinoembryonic antigen (CEA) was measured in the plasma by radioimmunoassay in 80 patients who were referred because of an apparently resectable lung cancer. There was no correlation between the initial CEA level and survival in patient whose tumours were found to be inoperable or had metastasized, with only 2 of 37 patients surviving longer than 2 years. Following a curative resection, the median survival for patients with initial CEA greater than 40 micrograms l-1 was 6 months compared to 14 months for those with CEA in the range 20-40 micrograms l-1, while 56 per cent of those with CEA less than 20 micrograms l-1 are still alive at 2 years. This trend was found to be highly significant (P < 0.005). Twenty-five per cent of all patients had an initial CEA greater than 40 micrograms l-1 and this was associated with a poor prognosis, despite complete surgical removal of the primary tumour. Such elevations, if discovered in the preoperative assessment, indicate a need for a thorough search for metastases.