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D Argyropoulos

Publications and source records attributed to D Argyropoulos.

3 recordsLinked to original sources
PubMed1998

Identification of a new endogenous platelet-activating factor-like molecule in gingival crevicular fluid.

Periodontal disease is an inflammatory disease and the major cause of tooth loss in adults. Bacteria and their products are the causative agents of this disease. Endogenous molecules mediate the inflammatory process and play a major role in its amplification and perpetuation as well as in the ensuing tissue destruction. The relationship between platelet-activating factor (PAF) and periodontal disease has not so far been examined thoroughly. We have isolated a phospholipid molecule with PAF-like activity from gingival crevicular fluid. This molecule, purified on HPLC, causes washed platelet aggregation with EC50 value 0.1 microM, based on phosphorus determination. It acts through PAF-receptors and is inactivated by PAF-acetylhydrolase. In addition, this phospholipid presents biological activity towards human platelets. The combination of the results obtained from the chemical and enzymic treatments, the biological assays as well as results from the electrospray analysis, leads to the conclusion that this phospholipid is a hydroxyl-PAF analogue with relative molecular mass 703. This PAF-like molecule may be implicated in periodontal disease.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1997

Synthesis of a new phosphoglycolipid with biological activity towards platelets.

Various synthetic as well as naturally occurring compounds have been found to exhibit platelet-activating factor (PAF)-like activity or to act as specific PAF inhibitors. In this work we have synthesized a new phosphoglycolipid, methyl 2,3,4-tri-O-acetyl-6-(1'-O-stearoyl-2'-O- acetyl-DL-glycero-3'-phosphoryl)-alpha-D-glucopyranoside ammonium salt, using a combination of known synthetic steps. This phosphoglycolipid was first purified on TLC (Rf 0.7, using chloroform/methanol/water, 65:25:4, v/v/v as solvent system). It was further purified onto a high performance liquid chromatography silica column with an elution system that contained acetonitrile and methanol (retention time 13.5 min). Its identification was based on chemical determinations and electrospray mass spectrometry analysis. The above compound induced washed platelet aggregation with an EC50 value at 2 x 10(-4) M. The aggregation curve was biphasic, the first wave of which was through the PAF way while the second one was through the ADP way. Treatment with acetylhydrolase resulted in a rapid decrease of the first wave of aggregation and in a slow decrease of the second wave. In lower concentrations, the phosphoglycolipid inhibited PAF- and thrombin-induced aggregation with IC50 values of the order of 10(-7) M. In conclusion, this phosphoglycolipid has a diverse biological activity. The PAF-like activity of this new lipid enforces the conception that PAF is a member of a large family consisting of lipid mediators.

Animals↗