Cholesterol monohydrate

Figure 3 Comparison of the densities (in g/cm ) of model compounds for membrane lipids computed from constant-pressure MD simulations with the coiTespondmg experimental values. The model compounds include solid octane and tricosane, liquid butane, octane, tetradecane, and eico-sane, and the glycerylphosphorylcholme, cyclopentylphosphorylcholme monohydrate, dilauroly-glycerol, anhydrous cholesterol, cholesterol monohydrate, and cholesterol acetate crystals. (Models from Refs. 18, 42, and 43).

Helical ribbons were found to be metastable intermediates in the process of cholesterol crystallization from bile in the gallbladder.160 Since gallstones result from the formation of cholesterol monohydrate crystals in supersaturated... 

During a Dissolution of Cholesterol Monohydrate in Glycochenodeoxycholate-Glycoursodeoxycholate-Lecithin Solutions and Calcium Carbonate Solubility in Their Solutions... 

Solubility of calcium carbonate was measured in mixed solutions of glycochenodeoxycholate, glyooursodeoxycholate and lecithin in the presence of cholesterol monohydrate disk in the ranges of pH from 7.5 to 9.0. ... 

H. Komatsu, Coincidence site conjugation of cholesterol monohydrate crystals, in Morphology and Growth Unit of Crystals, ed. I. Sunagawa, Tokyo, Terra Scientific Publications, 1989, pp. 761-75... 

Craven, B. M. (1976). Crystal structure of cholesterol monohydrate. Nature (London) 260 111. 

Figure 6 Phase diagram of the ternary mixture distearoylphosphatidylcholine (DSPQ/dioleoylphosphatidylcholine (DOPQ/cholesterol at 23° C, showing four regions of two-phase coexistencediquid crystalline and gel (La + Lp), liquid ordered and gel (Lo + Lp), liquid crystalline and liquid ordered (L + Lo), and liquid ordered and crystals of cholesterol monohydrate also one region of three-phase coexistence exists, liquid crystalline, gel and liquid ordered (La + Lp + Lo). (Reproduced from Reference 74 with permission.)...

Higuchi, W.I. Su, C.C. Park, J.Y. Gulari, E. Mechanism of cholesterol gallstone dissolution. Analysis of the kinetics of cholesterol monohydrate dissolution in taurocholate/ lecithin solutions by the mazer, benedek, and carey models. J. Phys. Chem. 1981, 85 (2), 127-129. 

A novel cholesterol-based cationic lipid has been developed that promotes DNA transfer in cells. Cholesterol monohydrate becomes anhydrous at 70-80°C. 

G9. Gollish, S. H., Bumstein, M. J., Ilson, R. G., Petrunka, C. N., and Strasberg, S. M., Nucleation of cholesterol monohydrate crystals from hepatic and gallbladder bile of patients with cholesterol gallstones. Gut 24, 836-844 (1983). 

Figure 19. Typical helical and tubular structures in bile, (a and b) High pitch helical ribbon and helically grown tubule, respectively, (c and d) Similar structures of low pitch, (e) Fracture of a low pitch tubule, (f) Subsequent growth of the low pitch tubule in (e) into a plate-like cholesterol monohydrate crystals after 12 h. Bar, 20 urn. Reproduced from ref. 202 (Chung et al., Proc. Natl. Acad. Sci. USA 1993, 90,11341) with permission from the Academy of Sciences of the USA.

Biomimetic coating of cholesterol with hydroxyapatite is characterised by an epitaxial relationship between cholesterol monohydrate recrystallised from polar solvents and hydroxyapatite, and thus enhances deposition rate. However, chemical modification of cholesterol, for example by phosphorylation destroys the epitaxy and hence this material fails to act as a viable template for calcium phosphate deposition (Laird, Mucalo and Yokogawa, 2006). This research may... 

Crystals of cholesterol monohydrate occur in various pathological conditions (Bogren and Larsson, 1961). The crystal structure of cholesterol monohydrate has been determined by Craven (1976). Cholesterol sulphate has been found in marine organisms and can form aqueous bilayer phases of the gel-type (Abrahamsson et al., 1977). 

In crystals of both cholesterol monohydrate (Craven, 1976) and anhydrous cholesterol (Shieh et al, 1977) the cholesterol molecules are organized into bilayers with the molecular axes approximately but not... 

CrystaUisation of biliary cholesterol monohydrate is a multiphase process not yet fuUy understood [60]. Bile is normally supersaturated with respect to cholesterol [61] which is solubilised by bile salts (the soluble end product of cholesterol metabolism, such as sodium glycocholate and sodium taurocholate [9]) within micelles, whose solubilising capacity is considerably increased by the incorporation of phosphohpid molecules such as lecithin [62]. Biliary vesicles contain virtually no bile salts but may accumulate cholesterol up to a cholesterol/phosphohpid ratio of 2 1 (by phospholipid transfer to micelles) [63]. These thermodynamically unstable (but kinetically stabilised) vesicles then aggregate and nucleate cholesterol crystals [64,65]. The mechanism of this crucial miceUe-to-vesicle transition has been the subject of various physicochemical studies, including, e.g. calorimetric, turbidimetric, dynamic light and neutron scattering methods [66-69]. 

Evolution of Ch dissolution kinetics requires an apparatus consisting of a) a static disk of Ch having a known surface for evaluation of the initial dissolution rate, b) powdered cholesterol monohydrate to evaluate equilibrium Ch solubility (Cs) and c) a rotating disk of Ch to evaluate the relative contribution of the resistances (interfacial or diffusion) during the dissolution process (Figure 2). 

Igimi and Carey[9] obtained the results reported in Table 1 using 100 mM solutions of bile acids and BS to dissolve cholesterol monohydrate crystals. Chenodeoxycholic acid and salts have a dissolution rate constant two to three fold faster than of UDCA[9]. 

Fig. 3 Cholesterol monohydrates crystal dissolution In a mixture of tauroursodeoxycholate Lecithin (80 20) at 37 C, observed by polarized light microscope. After 3 hours (B) the edges of the crystal are covered by birefringent liquid crystals made of cholesterol-lecithin in molar proportion of about one[11]. 

Dissolution rate studies of cholesterol monohydrate in bile acid-lecithin solutions using the rotating-disk method, J.Pharm.Sci., 65 685 (1976). 

H. Kwan, W. I. Higuchi, A. M. Molokhia, and A. F. Hofmann, Dissolution kinetics of cholesterol monohydrate in simulated bile. I. Influence of bile acid type and concentration, bile acid-lecithin ratio and added electrolyte, J.Pharm.Sci., 66 1094 (1977). 

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