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Lipid preparation

The sharpness of the transition in pure lipid preparations shows that the phase change is a cooperative behavior. This is to say that the behavior of one or a few molecules affects the behavior of many other molecules in the vicinity. The sharpness of the transition then reflects the number of molecules that are acting in concert. Sharp transitions involve large numbers of molecules all melting together. [Pg.269]

In contrast, solid lipid microparticles consisting of a tripalmitin matrix and cationic lipids prepared using the micromixer-based solvent extraction process as described by Emi et al. [50] were of monomodal size, showing a narrow size distribution in the submicrometer range (Table 8.1). [Pg.6]

The mean particle diameter was measured by photon correlation spectroscopy (PCS) with a Nanosizer N4 (Coultronics, Margency, France). The size and polydispersity of AmB lipid preparations depended on both the AmB/phospholipids ratio and the phospholipid composition. At a DMPC/DMPG molar ratio of 7/3, when the AmB content was below 10% w/w, large poly disperse particles were formed. At AmB ratios of 20% to 50% of total weight of phospholipids, a majority of submicronic particles were obtained. The smallest size, around 300 nm, and minimal polydispersity were achieved with AmB at 35% w/w that... [Pg.97]

Three such formulations are now available and have differing pharmacologic properties as summarized in Table 48-1. Although clinical trials have demonstrated different renal and infusion-related toxicities for these preparations compared with regular amphotericin B, there are no trials comparing the different formulations with each other. Limited studies have suggested at best a moderate improvement in the clinical efficacy of the lipid formulations compared with conventional amphotericin B. Because the lipid preparations are much more expensive, their use is usually restricted to patients intolerant to, or not responding to, conventional amphotericin treatment. [Pg.1057]

The lipid material precipitated upon mild acid treatment of the Boivin-extracted lipopolysaccharide is here termed a lipoidal precipitate. The fatty-acid profile (Table IV) of hydrolyzates of this material shows little variation between the seven lmmunotype strains. If the original lipopolysaccharides are first treated by phenol—water extraction, and the resultant materials then subjected to hydrolysis to release the lipid, the composition of the latter is significantly different it corresponds closely to the classic composition expected for lipid A. It is noteworthy that material extracted by the phenol—water (Westphal) method is rich in the Csaturated acid and in the hydroxy fatty acids having ten and twelve carbon atoms, whereas the and C g saturated acids present in the lipoidal precipitate, as prepared by the Boivin procedure, are absent or present at much lower levels in the lipid prepared by the Westphal procedure -9). It... [Pg.25]

Most cationic lipids described in the literature are synthesised by solution synthesis [36-39]. Depending upon the complexity of the structure, the synthetic routes vary from just one or two chemical steps, as in the case of DOTMA (1) and DC-Choi (3), to longer convergent synthesis, as for DOGS (5) (these three compounds being the earliest examples of cationic lipids prepared for transfection purposes [41, 68, 69]) (see Fig. 2). [Pg.19]

Hamouda, T., and Baker, J. R., Antimicrobial mechanism of action of surfactant lipid preparations... [Pg.114]

This assay is really meant to be used in experiments in which milligram quantities of lipid are available for an initial structure proof of an unknown compound. Obviously, it is not employed in lipid preparations from small quantities of cells (e.g., 2.0 X 108 cells/ml), used in signal transduction experiments. There simply is not sufficient sample for such an analysis. An alternative approach, if enough material is available, is to have a C, H, N, P analysis performed by a commercial organic analytical laboratory. As mentioned, the major difficulty is that the lipid is often a very viscous material, and this makes reproducible sampling a problem. Also, in the author s experience, the techniques used by commercial laboratories give lower-than-expected results even with synthetic saturated phospholipids. It may have to do with the combustion techniques used or unusual behavior of these compounds under assay conditions. The exact reason for this behavior is not clear. [Pg.64]

Two different procedures can be used to determine the distribution of the above three classes of phosphoglycerides in a cellular lipid preparation. The first involves an enzymatic cleavage and the second involes a chemical approach. These are outlined briefly as follows. [Pg.119]

In order to prepare liposomes, the lipid preparation is dried at low temperature under an inert gas atmosphere (protect the lipid from oxidation). The lipid film is swollen with water or buffered aqueous solution and several freeze-thaw cycles are carried out to get optimal rehydration of the lipid. The rehydrated lipid preparation is filtered using membrane filters with defined pore size. After repeated filtration steps (extrusion) an unilamellar liposome preparation with a defined size distribution is obtained. Large unilamellar vesicles (LUV) are produced in this way. LUV s are about 100 nm in size the thickness of the lipid bilayer is about 4 nm. Even smaller liposomes can be derived from sonication (sonication probe or ultra-sonication bath). Separation of the prepared liposomes... [Pg.465]

Self-limited disease Amphotericin 6 0.3-0.5 mg/kg/day x 2-4 weeks (total dose 500 or ketoconazole 400 mg orally daily x 3-6 months can be beneficial in patients with severe hypoxia following inhalation of large inocula Antifungal therapy generally not useful for arthritis or pericarditis NSAIDs or corticosteroids can be useful in some cases Most lesions resolve spontaneously surgery or antifungal therapy with amphotericin B 40-50 mg/dayx2-3 weeks or itraconazole 400 m day orally x 6-12 months can be beneficial in some severe cases mild to moderate disease can be treated wHh itraconazole for 6-12 months Amphotericin B 0.7 mg/k day, for a total dose of SSm kg (or 3 rng/k day of one of the lipid preparations) prednisone 60 mg daily tapered over 2 weeks/ followed by itraconazole 200 rng twice daily for 6-12 weeks in patients who do not require hospitalization, itraconazole 200 mg once or twice daily for 6-12 weeks can be used... [Pg.413]

Sensitive analytical procedures will be required to distinguish contaminants from lipid peaks within the preparation. By-products may be present from the synthetic processes used to produce the lipids or if copurified from the natural source. For example, common impurities in synthetic diacyl chain lipids are the monoacyl forms, which are generally more toxic to biological systems. Endotoxins and pyrogens either may be detectable in a lipid preparation " or difficult to detect due to the lipids shielding against the analytical reagents. ... [Pg.985]

Lipid preparations of amphotericin B are effective in animal models of blastomycosis, but they have not been evaluated adequately in humans. Limited clinical experience suggests that these preparations may provide an alternative for patients unable to experience standard therapy with amphotericin B because of toxicity. Surgery has only a limited role in the treatment of blastomycosis. [Pg.2171]

Lipid formulations of amphotericin B may be indicated in patients with impaired renal function and in those who develop nephrotoxicity while receiving deoxycholate amphotericin B. The lipid-based formulations may be preferred as initial therapy in patients with marginal renal function or in patients receiving other nephrotoxic drugs. Although these preparations appear less toxic than standard preparations, only limited data regarding their relative efficacy for invasive aspergillosis are available at this time because the studies with the lipid preparations have been open label or with historical conventional amphotericin B controls. " ... [Pg.2184]

In a procedure for the preparation of m-9-octadecenyl bromide,4 a solution of 26.8 g. (0.1 mole) of pure cis-9-octadecenol (available from the Lipids Preparation Laboratory of the Hormel Institute, Austin, Minn. 55912) in 90 ml. of pyridine is stirred in an ice bath under a stream of purified nitrogen and 17.2 g. (0.15 mole) of... [Pg.131]

Weigh lipids, Prepare dye solu lion Prepare buffer Dissolve lipids in solvent mixture. , ... [Pg.200]

In recent years most studies on oxidized phospholipids have been performed using mixtures of oxidation products that are generated from their polyunsaturated parent compounds like PA-PC or oxidized lipoprotein particles (e.g. oxLDL). These preparations contain a large variety of different substances differing in structure, polarity and hydrophobicity as well as bioavailability. In many of these oxidized lipid preparations, neither the type nor the content of the individual oxidized components was known. Therefore, the respective compounds contribute to the apparent biological activities of oxidized lipid mixtures to a different and unpredictable extent. Thus, it will be desirable to concentrate on chemically defined lipid species in the future. [Pg.362]

Transient azotemia occurs in 80% of patients who receive C-AMB for deep mycoses. Toxicity is dose-dependent and increased by concurrent therapy with other nephrotoxic agents (e.g., aminoglycosides, cyclosporine). Permanent impairment is uncommon in adults with normal renal function unless the cumulative dose is >3-4 g. Renal tubular acidosis and wasting of K and Mg also may occur during and for several weeks after therapy, often requiring repletiort Administration of 1 L of normal saline intravenously prior to C-AMB administration is recommended for adults who can tolerate the Na load. Azotemia occurs less frequently with lipid preparations of amphotericin, and saline loading is not needed. [Pg.799]

The excitation spectrum of di-8-ANEPPS is altered when it lines up with the phospholipid/sterol dipoles and leads to electronic redistributions within the probe molecule promoting red or blue shifts in the excitation spectrum depending on the magnitude and direction of the dipole moment of the ambient environment that the probe finds itself in. These phenomena are illustrated in Figure 5.4, in which membranes with various lipids preparations (etc) are prepared and lead to spectral differences. [Pg.79]

The use of liposomes for transfection purposes was first described in 1987. Cationic lipids prepared for this purpose are commercially available i.e. Cytofectintrade or Lipofectintrade). However, failure of transfection in the presence of serum is possible, but much more important are side-effects such as lung inflammatory reactions.The main drawback of the use of conventional degradable polymers as delivery agents is their thermodynamic instability, which results in a short in vivo lifetime of the active species, besides their polydispersity. ... [Pg.344]

Fatty acid methyl esters of fish and commercial feed total lipids prepared using a solution 0.5N KOH in CH3OH 90% and extracted with n-hexane. [Pg.289]

The combined effects of pH and freeze-thaw (2nd incubation, see Materials and Methods) on OEA are represented in Fig. 2. We point out first that the freeze-thaw step in PSH-lipid preparation has been often used as a means of enhancing association of PSII particles with specific thylakoid lipids (see, e.g., [11,12]). It is seen in Fig. 2 that freeze-thaw diminishes OEA in PSII particles incubated in absence of PGV. Fig. 2 (inset) shows, furthermore, that a low temperature treament (143 K) followed by thawing does not affect OEA in PSII-PGV. [Pg.946]


See other pages where Lipid preparation is mentioned: [Pg.131]    [Pg.426]    [Pg.101]    [Pg.305]    [Pg.314]    [Pg.314]    [Pg.136]    [Pg.12]    [Pg.266]    [Pg.39]    [Pg.210]    [Pg.338]    [Pg.324]    [Pg.237]    [Pg.553]    [Pg.85]    [Pg.47]    [Pg.231]    [Pg.320]    [Pg.251]    [Pg.316]    [Pg.236]    [Pg.238]    [Pg.239]    [Pg.240]    [Pg.245]    [Pg.209]   
See also in sourсe #XX -- [ Pg.4123 ]




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