Vesicle interactions interaction studies

A further partihon system based on the use of liposomes, and commercialized under the name Transil [110, 111], has shown its utiUty as a UpophiUcity measure in PBPK modeling [112]. Fluorescent-labeled liposomes, called fluorosomes, are another means of measuring the rate of penetration of small molecules into membrane bilayers [113, 120]. Similarly, a colorimetric assay amenable to HTS for evaluating membrane interactions and penetrahon has been presented [116]. The platform comprises vesicles of phospholipids and the chromahc Upid-mimehc polydiacetylene. The polymer undergoes visible concentrahon-dependent red-blue transformahons induced through interactions of the vesicles with the studied molecules. 

Dunnick, J.K., McDougall, R., Aragon, S., Coris, M., and Kriss, J. (1975) Vesicle interactions with polyamino acids and antibody in vitro and in vivo studies./. Nucl. Med. 16, 483-487. 

The accumulated phosphate reacts with calcium available to form apatite. Calcium may be concentrated within the vesicles by virtue of a lipid-calcium interaction and possibly by active calcium transport across the vesicle membrane458. Recent studies have led to the discovery of PL-Ca-Prcomplexes in calcifying tissues. These Pl-Ca-Pj complexes110 and certain proteolipids122,491 have been shown to rapidly nucleate HA from metastable Ca-P04 solutions. There is evidence for the existence of these complexes in matrix vesicles135. ... 

In a more recent study, vesicle skin interactions were examined with confo-cal laser scanning microscopy (CLSM) [36], A large number of liposome compositions were examined. These studies revealed that the liposome constituents were only present in the outermost layers of the SC and that the constituents only acted as penetration enhancers, which is in contrast to the studies of Holland et al. Whether these differences in findings are due to another study design or to a difference in vesicle components is not clear. 

A third method to increase the skin transport is encapsulation of drugs in vesicles. Although several studies have been performed, the interactions between vesicles and skin is still largely unknown. In this chapter a review will be given on the state of the an in skin vesicle rese ch. 

Glavinas H, Mehn D, Jani M, Oosterhuis B, Heredi-Szabo K, Krajcsi P (2008) Utilization of membrane vesicle preparations to study drug-ABC transporter interactions. Expert Opin Drug Metab Toxicol 4 721-732. 

EPR spectrum of Cu(II) complex described. 5 =2.0045,2.053. DAP = 0.10 M dodecylammonium propanoate. ) da(N)/dr=0.215pTK-MnTHF. ) Measurement of in 15 solvents. Variation of % vs. solvent polarity and T measured. Study of interaction with surfactant vesicles. ) Temperature dependent study. Measurements in HjOF polyvinyl alcohol gel. ) Measurement of rotational diffusion. Formation of dimers at low temperature measurements at 9 and 35 GHz. ) da(N)/d7 =0.109pTK-MnCCl4. ... 

Experimentally, the difference between strong and weak adhesion has been seen clearly. With light microscopy [46], the mutual interaction of vesicles has been studied and large rounded contact regions corresponding to weak adhesion were found. Spherical cap-like configurations are seen in micro-pipet experiments [48] as well as in freeze-fracture electron microscopy for smaller vesicles [51]. 

Relini, A., Cassinadri, D., Miighani, Z., Brandt, O., Gambacorta, A. Calcium-induced interaction and fusion of archaeobacteiial Upid vesicles a fluorescence study. Biochem Biophys Acta. 1994,1194,17-24. 

The driving forces of the blackberry self-assembly process are unique and differ from many types of traditional systems that have been well studied. Unlike surfactant micelles and vesicles, hydrophobic interactions do not contribute to the blackberry formation because the POMs have no hydro-phobic moieties. In colloidal systems, self-assembly occurs by van der Waals forces. As previously mentioned, van der Waals forces do not contribute significantly to POM self-assembly. 

Two nucleation processes important to many people (including some surface scientists ) occur in the formation of gallstones in human bile and kidney stones in urine. Cholesterol crystallization in bile causes the formation of gallstones. Cryotransmission microscopy (Chapter VIII) studies of human bile reveal vesicles, micelles, and potential early crystallites indicating that the cholesterol crystallization in bile is not cooperative and the true nucleation time may be much shorter than that found by standard clinical analysis by light microscopy [75]. Kidney stones often form from crystals of calcium oxalates in urine. Inhibitors can prevent nucleation and influence the solid phase and intercrystallite interactions [76, 77]. Citrate, for example, is an important physiological inhibitor to the formation of calcium renal stones. Electrokinetic studies (see Section V-6) have shown the effect of various inhibitors on the surface potential and colloidal stability of micrometer-sized dispersions of calcium oxalate crystals formed in synthetic urine [78, 79]. 

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