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The glassy state of indomethacin was examined by thermomechanical analysis (TMA). The influences of the method of preparation and the measurement conditions of the sample on the TMA curves were investigated. The TMA curves of glassy indomethacin having hemispherical and plane surfaces were examined. Expansion was observed on the TMA curves in the region of glass transition temperature (Tg), which had been confirmed by differential scanning calorimetry. The TMA curves for the sample with the plane surface showed distinct expansion. It was further found that the glass transition shifted to lower temperatures as the heating rate was decreased and the loading increased. The TMA curves of brucine, griseofulvin and phenobarbital were similar to that of indomethacin. The relaxation process of glassy indomethacin below Tg was followed in terms of the variation of mechanical properties of samples.

An ether extract of normal human feces showed inhibitory effects on the activities of several mutagens in the Ames tests. By addition of the ether extract at an amount equivalent to 0.5 g of a sample of feces, the mutagenicity of 1.5 nmole of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) on Salmonella typhimurium TA98 was completely inhibited. No killing of the bacteria was detected during this treatment. Other mutagens also subject to the inhibition were 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-9H-pyrido[2,3-b]indole (Glob-P-2), 2-amino-3-methylimidazo[4,5-d]quinoline (IQ), benzo[a]pyrene and aflatoxin B1. Apart from these mutagens, which require S9 for their activation, the direct mutagen prepared from Trp-P-1 by treatment with S9 was also inhibited by the fecal extract. The inhibitory principles in the fecal extract were fractionated by thin-layer chromatography on silica gel and were identified as oleic and linoleic acids. Whereas these unsaturated fatty acids showed strong inhibitory activities, saturated fatty acids, i.e, stearic and palmitic acids, did not exhibit any inhibition. Although the physiological significance of these effects of oleate and linoleate is yet to be elucidated, this finding has indicated that care must be taken in screening mutagens by the Ames tests to avoid false negatives resulting from the presence of unsaturated fatty acids in the system.

A method has been developed for the determination of taurine by gas-liquid chromatography. The method involves the conversion of taurine into its N-isobutyloxycarbonyl di-n-butylamide derivative and chromatography on a 1.5% OV-17 column. The derivative can be prepared in quantitative yield, having good chromatographic properties. The calibration curve for taurine in the range 5-500 nmol was linear and sufficiently reproducible for quantitative determination. Complex biological material such as urine can be analysed accurately and precisely by this method without prior clean-up of the sample.

By using the Salmonella/microsome system, it was found that the activity of mutagens present in the basic fraction of cooked-ground-beef was completely suppressed by addition of the acidic fraction obtained from the cooked-beef. The suppression was ascribable to the presence of oleic acid in the acidic fraction. This finding indicates that no, or diminished, mutagenicity would be found in materials containing fat.