コレステロール結石中の一水塩コレステロールならびにステロール類の赤外吸収度測定法,X線分析ならびに質量スペクトル測定法による再検討

抄録

Analytical studies on cholesterol monohydrate and non-cholesterol sterols in 70 specimens of "so-called pure cholesterol stones" were performed by means of infrared spectroscopy, X-ray diffraction analysis and mass spectrometry. These 70 specimens contained more than 95% cholesterol as the main component and were selected from 380 pieces of biliary calculi which had been removed from 346 cases with cholelithiasis in the First Department of Surgery, Nippon Medical School, over a 10 year period, using infrared spectroscopy. The results were as follows:
1) The specimens of pure cholesterol gallstones analysed immediately after operative removal by X-ray diffraction showed a monohydrate pattern (Type I ). Almost all these specimens exhibited a transformation in X-ray diffraction pattern from Type I to an anhydrous pattern (Type III) via an intermediate pattern of a mixture of monohydrate and anhydrous patterns (Type II) while they were kept at room temperature, although some specimens remained unchanged even 5 years later. Similar transformation from Type III to Type I via Type II and the reverse from Type I to Type III were observed experimentally under high humidity atmospheric conditions and in a desiccator respectively. The contents of H₂O in the specimens with Type I were evaluated to be 6% to 8% from changes in weight, and to be 4% to 6% in mass spectrometry respectively. On the other hand thermal analysis revealed only a small amount of H₂O even in the specimens with Type III of X-ray diffraction pattern.
2) Mass peaks at M/Z 400, 412 and 414 were found on the gas chromatograph double-focusing mass spectra (using GC/MS, IB & DI) from the specimens which were sampled from several different portions of ten pure cholesterol stones. On the other hand in trimethylsilyl ether of the same samples the mass peaks were observed at M/Z 472, 484 and 486. Accurate mass measurement of these peaks gave rise to a rational formula of C₂₈H₄₈O, C₂₉H₄₈O and C₂₉H₅₀O respectively. Together with reference to Ilias's report and the results of the analysis of commercial chemicals, the non-cholesterol sterols were identified to be campesterol, stigmasterol and sitosterol respectively. Relative contents of these non-cholesterol sterols determined in comparison with peak area calculation in ion mass chromatogram revealed the values of 1.22±0.07(SE)% in the components with M.W. 400, and 0.2±0.02(SE)% in the components with M.W. 414. From the results obtained it is concluded that these non-cholesterol sterols are present homogeneously in all portions of cholesterol gallstones as trace components.