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Solitary versus multiple cholesterol gallbladder stones (1993)

Wolpers, C. ; Hofmann, A. F.

Springer

Journal of molecular medicine 71 (1993), S. 423-434

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ISSN: 1432-1440

Keywords: Cholecystolithiasis ; Supersaturation ; Gallstones ; Cholesterol ; Cholecystitis ; Occlusion of the cystic duct

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Summary The development and growth pattern of solitary and multiple cholesterol gallbladder stones was defined using cholecystography in a prospective study of 48 patients whose initial cholecystograms indicated a stone-free gallbladder and who developed gallstones within the subsequent 5 years. Radiological observations performed over 365 patient-years were complemented by macroscopic examination, radiograms, scanning electron microscopy, and chemical analysis of gallstones from these and other patients obtained at cholecystectomy. Solitary gallstones were found to develop after a precursor phase of over 2 years during which free-floating crystal laminae of cholesterol formed. These laminae subsequently aggregated loosely and underwent external compaction and internal remodeling by movement of cholesterol molecules to form compact spheroids. A single lamina was observed to function as a nucleus for the development of a solitary stone shaped as an ellipsoid. About 10% of solitary stones were found to have a solitary pigment stone in their center. In contrast, multiple cholesterol gallstones formed without a precursor phase. Innumerable, very thin cholesterol crystals appeared which very abruptly aggregated to form spheres of up to 1 mm in diameter. Within 3 months a second aggregation took place in which these spheres coalesced to form mulberry stones. Mulberry stones in turn were transformed either to faceted stones (if many were present in the gallbladder) or to barrel stones (if few were present) over a period of 3 years. It is proposed that temporary occlusion of the cystic duct leads to supersaturation of bile with calcium bilirubinate and/or calcium carbonate which in turn promotes deposition of either or both of these calcium salts on the surface of single or multiple gallstones. For multiple gallstones, this process or the deposition of additional cholesterol crystals seals the gallstone surface and is followed by metamorphosis of the stone center.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00180054

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Collective and molecular dynamics in ferroelectric liquid crystals: from low molar to polymeric and elastomeric systems (1992)

Kremer, F. ; Schönfeld, A. ; Hofmann, A. ; [et al.]

New York, NY : Wiley-Blackwell

Polymers for Advanced Technologies 3 (1992), S. 249-255

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ISSN: 1042-7147

Keywords: Ferroelectric liquid crystals ; Polymers ; Dielectric spectroscopy ; Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Broadband dielectric spectroscopy delivers in the frequency range from 10 Hz to 1010 Hz two collective dielectric loss processes (soft and Goldstone modes) and one molecular relaxation (β-relaxation). The soft mode and Goldstone mode are assigned to the fluctuation of the amplitude and the phase of the helical superstructure. The β-relaxation corresponds to the libration (hindered rotation) of the mesogene around its long molecular axis. At the SmA-SmC* phase transition this process does not split or broaden, and the temperature dependence of its relaxation rate does not show any deviation from an Arrhenius-like behavior. Its dielectric strength does not decline at the SmA-SmC* phase transition. These experimental findings are in contrast to the common explanation of the origin of the saturation polarization (“induced spontaneous polarization”), which is based on the existence of a “free” rotation inside the SmA phase and its strong hindrance in the ferroelectric SmC* phase. Furthermore, the high frequency results require a reformulation for the (generalized) Landau theory as applied to the SmA-SmC* phase transition. In comparing low molar mass and polymeric (elastomeric) FLC, the collective and molecular dynamics are qualitatively similar, independent of the molecular architecture (e.g. side-chain, combined main- and side-chain or crosslinked systems).

Additional Material: 13 Ill.