| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1988: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
Recently it has been revealed that the presence of pulmonary intravascular macrophages (PIM) and an important role of these cells in the endotoxin induced lung injury in sheep. However, still it is not solved about the phagocytic activities of the PIM to the foreign particles. In this study we demonstrated the differences of the reactivities of the PIM to the differently composed and differently charged liposomes in awake sheep.
We prepared two negatively charged liposomes (PS & PG liposomes), a positively charged SA-liposomes and two neutral liposomes (PC & PE liposomes) by a reversed- phage evaporation method. We injected these liposomes intravenously (0.05- 3.2umol/kg) and measured pulmonary arterial pressure responses in each liposome in awake sheep. We also measured arterial blood thromboxane B_2 concentrations.
Negatively charged liposomes did not aggregate with plasma, neither did a neutral PE liposomes. Positively charged SA liposomes aggregate with plasma. Neutral PC liposomes aggregate spontaneously.
The PG liposomes caused a greater rise in pulmonary arterial pressure than did the PS liposomes, although both are negatively charged. The positively charged SA liposomes produced the same dose-response curve as PS liposomes. The neutral PE liposomes caused a greater rise in the pulmonary arterial pressure than did the PC liposomes, though both liposomes are neutral. PC liposomes, though aggregate spontaneously, caused little or no pressure rise in the pulmonary arterial pressure.
From these findings, the chemical composition of the liposomes had any effect or no effect (PC liposomes) on the pulmonary arterial pressure responses in sheep.
Abbreviation used are as follows; PC; phosphatidylcholine, PG; phosphatidylglycerol, PS; phosphatidylserine, PE; phosphatidylethanolamine, SA; stearylamine.
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