Toshio Muramatsu

Mass spectrometric evidence for the presence of platelet-activating factor (1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in human amniotic fluid during labor

Evidence is presented for the existence of platelet-activating factor (PAF) in human amniotic fluid during labor by gas-liquid chromatographic (GLC) and mass-spectrometric (MS) analysis. The unique ether-linked phospholipid was identified only in an amniotic fluid obtained from women during labor, and its alkyl side chain was composed exclusively of octadecyl residue.

A facile method for the preparation of 1-O-alkyl-2-O-acetoyl-sn-glycero-3-phosphocholines (platelet activating factor)

Abstract Biologically active 1-O-alkyl-2-O-acetoyl-sn-glycero-3-phosphocholines are prepared in good yields from ratfish (Hydrolagus colliei) liver oil, an inexpensive natural product, that contains over 70% neutral ether lipids.

Phase transitions of phospholipids in monolayers and surface viscosity

Abstract The surface pressures and the surface viscosities of lecithin, cephalin and its analogs were measured at the air—water and the oil—water interfaces. It was found that the surface viscosity of the phospholipids used in this study was very high, and was comparable to those of some polymer films at the oil—water interface as well as at the air—water interface under the conditions where the monolayers were condensed. The plateaus indicating the phase transitions in monolayers were clearly observed on the pressure-area curves at the oil—water interface in all of the specimens studied. It was found that the phase transitions exactly corresponded to the abrupt increases in surface viscosity. From the results thus obtained, an intermolecular ionic linkage between neighboring molecules in the monolayers is discussed.

Critical structure formation in ampholytic phospholipid monolayers as analyzed by calcium binding characteristics

Abstract The binding of calcium ions was studied by radiotracer method for the monolayer of three ampholytic phospholipids differing in structural separation between phosphate and ammonium groups. The phospholipids used were DL-α-dipalmitoylphosphatidylethanolamine (PE), -n-propanolamine (PNP), and -iso-propanolamine (PIP), all synthesized and purified by thin layer chromatography. The reactivity of these lipids to calcium ions decreased in the following order PE

Surface chemical properties of homologs and analogs of lysophosphatidylcholine and lysophosphatidylethanolamine in water

Abstract Equilibrium surface tension versus concentration curves for aqueous solutions of homologs of lysophosphatidylcholine (lysoPC) and lysophosphatidylethanolamine (lysoPE) and two analogs of lysoPC, that is, alkylphosphorylcholine and partially fluorinated lysoPC were measured by the Wilhelmy plate method using a ground-glass plate. From these measurements the critical micelle concentration (cmc), the molecular area in saturated adsorption, the standard chemical potential of adsorption from the infinitely dilute solution to the saturated adsorption surface, and the standard chemical potential of micellization were obtained for each lipid. Further, the measurements of the free energy of formation of black film, the steady-state fluorescence anisotropy in the non-polar region of black film and the rate of growth of black film were performed separately for single foam films of the above lipids, together with the measurement of foam stability. By comparing these surface chemical properties among the respective lysophospholipids, the difference in foam stability between lysoPC and lysoPE is discussed in terms of these static and dynamic properties of solution surfaces and single foam films.

A new procedure for the acetylation of lipids

Abstract Long-chain alcohols and other lipids containing hydroxy groups are acetylated at room temperature by reaction with acetic anhydride in acetonitrile in the presence of an ion exchanger.

Synthesis of phospholipids. III. Synthesis of 1,2-dipalmitoyl-rac-glyceryl-3-phosphoryl-3′β-cholesterol and 1,2-dipalmitoyl-rac-glyceryl-3-phosphoryl-20′-(3β-hydroxy norpregn-5-ene)

Abstract The chemical synthesis of two new glycerophosphatide analogues containing steroid groups, i.e., 1,2-dipalmitoyl-rac-glyceryl-3-phosphoryl-3′β-cholesterol and 1,2-dipalmitoyl-rac-glyceryl-3-phosphoryl-20′-(3β-hydroxy norpregn-5-ene) is described.

Temperature dependent ionic structure of phospholipid monolayers.

Radiotracer studies of calcium adsorption to dipalmitoylphosphatidyl-alkanolamine monolayers measured at various temperatures showed that the binding constant of calcium increased with temperature up to around 30 degrees C but the decreased on exceeding this critical temperature. The temperature dependent ionic structure of ampholytic phospholipid monolayers are discussed.

Ionic properties of phospholipids at the oil/water interface

Abstract Surface pressures and surface viscosities of dipalmitoylphosphatidylethanolamine and its polar group analogues were measured at the hexane/water interface as a function of bulk pH. The monolayers expanded as the bulk pH was shifted from neutral to alkaline and gave rise to an increase in surface pressure at a constant area, and the surface viscosity was simultaneously reduced at high pH. For the increase in surface pressure, theoretical values were calculated using the Gouy-Chapman equation for the electrical double layers produced by shifting pH, and good agreements were obtained with the measured ones from which a simple mechanism was deduced for the increase in pressure. The ionic dissociation characteristics of amino groups of the lipids were discussed taking p K a values given in the above calculations into account. The reduction of the surface viscosity was thought to be attributable to disintegration of zwitter ionic structure in the condensed monolayers.

Pyrophosphatidic acid in mushrooms

The distribution of pyrophosphatidic acid in mushrooms was investigated. Total lipids of mushrooms were extracted from their fruit body, and the pyrophosphatidic acid fraction was isolated by DEAE-silica gel column and silicic acid column chromatography. The presence of pyrophosphatidic acid was tested by thin layer chromatography. Of the 43 species of mushrooms examined, the acid was found in 30. The pyrophosphatidic acid was identified by chromatography, IR spectroscopy and quantitative degradation with aqueous pyridine to produce phosphatidic acid. Chemically synthesized pyrophosphatidic acid was used as standard.