References: Lecithin
Environ Health Perspect. 1992 Jul;97:225-31.
Influence of surfactant components and exposure geometry on the effects of quartz and asbestos on alveolar macrophages.
Schimmelpfeng J, Drosselmeyer E, Hofheinz V, Seidel A.
Kernforschungszentrum Karlsruhe, Hauptabteilung Sicherheit/Biophysik, Federal Republic of Germany.
Bovine (BAM) and rat (RAM) alveolar macrophages were incubated in vitro with DQ12 quartz or UICC chrysotile asbestos either alone or in the presence of dipalmitoyl lecithin (DPL). The reaction of the cells of both species to the untreated dust particles was similar qualitatively and quantitatively, with a loss of viability and release of lactate dehydrogenase and N-acetyl-beta-glucosaminidase after 20 hr of incubation. In the presence of DPL, the toxicity of quartz to BAM disappeared completely, whereas the protective influence of the phospholipid was distinctly diminished in the case of RAM. The presence of lavage fluid was less effective than that of pure DPL. There was no protective influence of DPL with asbestos either for BAM or for RAM. The effects of phagocytizable, suspended quartz particles were compared with the effects of the same type of particles fixed on a glass surface to exclude the possibility of phagocytosis. The effect of the suspended particles on the viability and release of enzymes was more pronounced than that of the fixed particles. On the other hand, superoxide anion production was stimulated to a much higher degree by the fixed quartz particles. This could be explained by the continuing contact of the outer cell membrane with the silica surfaces, whereas free particles were rapidly phagocytized. The release of lysosomal enzymes induced by fixed quartz particles was a secondary phenomenon following cell death.
Laxative online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1327736&dopt=Abstract lecithin
J Lipid Res. 1995 Mar;36(3):485-95.
Plasma lipid transport in the hedgehog: partial characterization of structure and function of apolipoprotein A-I.
Sparrow DA, Laplaud PM, Saboureau M, Zhou G, Dolphin PJ, Gotto AM Jr, Sparrow JT.
Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.
Apart from exhibiting the presence of lipoprotein [a] in its plasma, another interest of the European hedgehog in lipoprotein research lies in the quantitative prominence of a complex spectrum of high density lipoproteins (HDL) and very high density lipoproteins (VHDL) as cholesterol transporters in plasma (Laplaud, P. M. et al. 1989. Biochim. Biophys. Acta. 1005: 143-156). We, therefore, initiated studies in the field of reverse cholesterol transport in the hedgehog. As a first step, we characterized apolipoprotein A-I (apoA-I), the main protein component of hedgehog HDL and VHDL. Proteolytic cleavage of apoA-I (M(r) approx. 27 kDa) using two different enzymes resulted in two sets of peptides that were subsequently purified by high performance liquid chromatography, and that allowed us determination of the complete protein sequence. Hedgehog apoA-I thus consists of 241 amino acid residues and exhibits an overall 58% homology to its human counterpart, i.e., the lowest value observed to date among mammalian species. However, it retained the general organization common to all known apoA-Is, i.e., a series of amphipathic helical segments punctuated by proline residues. Circular dichroism experiments indicated a helical content of approx. 45%, increasing to approx. 58% in the presence of lecithin unilamellar liposomes. Apart from other differences, amino acid composition analysis shows that hedgehog apoA-I contains four isoleucine residues, while this amino acid is totally absent from the corresponding protein in higher mammals. Polyclonal antibodies raised against hedgehog apoA-I failed to detect any cross-reactivity between the animal and human proteins, although comparative prediction
Pharm Res. 1997 Apr;14(4):458-62.
Cytotoxicity of solid lipid nanoparticles as a function of the lipid matrix and the surfactant.
Muller RH, Ruhl D, Runge S, Schulze-Forster K, Mehnert W.
Department of Pharmaceutics, Biopharmaceutics & Biotechnology, Free University of Berlin.
PURPOSE: Assessment of the in vitro cytotoxicity of solid lipid nanoparticles (SLNs) as a function of lipid matrix (Dynasan 114, Compritol ATO 888), and stabilizing surfactant (poloxamers, Tween 80, soya lecithin, and sodium dodecyl sulphate). Comparison with other colloidal carriers should determine their potential use in the clinic. METHODS: SLNs were produced by high pressure homogenisation. Cytotoxicity was assessed by measuring the viability of HL60 cells and human granulocytes after incubation with SLNs. Particle internalisation was quantified by chemiluminescence measurements. RESULTS: The nature of the lipid had no effect on viability; distinct differences were found for the surfactants. Binding to the SLN surface reduced markedly the cytotoxic effect of the surfactants, e.g., up to a factor of 65 for poloxamer 184. The permanent HL60 cell line-differentiated from cells with granulocyte characteristics by retinoic acid treatment-yielded results identical to freshly isolated human granulocytes. In general, the SLNs showed a lower cytotoxicity compared to polyalkylcyanoacrylate and polylactic/glycolic acid (PLA/ GA) nanoparticles. CONCLUSIONS: Because the results are identical when using human granulocytes, differentiated HL60 cells can be used as an easily accessible in vitro test system for i.v. injectable SLN formulations. The SLNs appear suitable as a drug carrier system for potential intravenous use due to their very low cytotoxicity in vitro.
Laxative online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9144731&dopt=Abstract lecithin
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