AIM： Platelet-activating factor （PAF） is a pro-inflammatory and angiogenic lipid mediator. Here we aimed to investigate levels of PAF, lyso-PAF （the PAF precursor）, phospholipase A2 （PLA2, the enzymatic activity...AIM： Platelet-activating factor （PAF） is a pro-inflammatory and angiogenic lipid mediator. Here we aimed to investigate levels of PAF, lyso-PAF （the PAF precursor）, phospholipase A2 （PLA2, the enzymatic activity generating lyso-PAF）, acetylhydrolase activity （AHA, the PAF degrading enzyme） and PAF receptor （PAF-R） transcripts in cirrhotic liver and hepatocellular carcinoma （HCC）. METHODS： Twenty-nine patients with HCC were enrolled in this study. Cirrhosis was present in fourteen patients and seven had no liver disease. Tissue PAF levels were investigated by a platelet-aggregation assay. Lyso- PAF was assessed after its chemical acetylation into PAR AHA was determined by degradation of [^3H]-PAE PLA2 levels were assessed by EIA. PAF-R transcripts were investigated using RT-PCR. RESULTS： Elevated amounts of PAF and PAF-R transcripts 1 （leukocyte-type） were found in cirrhotic tissues as compared with non-cirrhotic ones. Higher amounts of PAF and PAF-R transcripts 1 and 2 （tissue-type） were found in HCC tissues as compared with non-tumor tissues. PLA2, lyso-PAF and AHA levels were not changed in cirrhotic tissues and HCC. CONCLUSION： While the role of PAF is currently unknown in liver physiology, this study suggests its potential involvement in the inflammatory network found in the cirrhotic liver and in the angiogenic response during HCC.展开更多
This review described origination, biosynthesis and functions of platelet-activating factor （PAF） in the reproductive system of mammals and human beings. The article mainly focused on biological roles of the phospho...This review described origination, biosynthesis and functions of platelet-activating factor （PAF） in the reproductive system of mammals and human beings. The article mainly focused on biological roles of the phospholipid mediator in sperm fertilization and embryonic implantation. As an autocrine product of sperm and embryos, PAF markedly stimulates sperm motility and fertilization and serves as a capacitation factor in a ligand-receptor manner, After fertilization, embryo-derived PAF improves its own development, especially from fertilized ova to blastocyst stage and is thought to act as an embryo growth factor in the same manner as on sperm. Its mechanism of action was also clarified. At the end, it was presented some advances in its clinical application, followed by discussion of some issues possibly concerning in its current application.展开更多
Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion cha...Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.展开更多
AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated i...AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCh for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS： Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels （P〈0.01, P〈0.01, P〈0.05, respectively）. Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats （P〈0.01）. Portal injection of PAF （1 g/kg WT） increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups （54% in control rats and 42% in cirrhotic rats）. Injection of the PAF antagonist BN52021 （5 mg/kg WT） decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION： The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in drrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.展开更多
文摘AIM： Platelet-activating factor （PAF） is a pro-inflammatory and angiogenic lipid mediator. Here we aimed to investigate levels of PAF, lyso-PAF （the PAF precursor）, phospholipase A2 （PLA2, the enzymatic activity generating lyso-PAF）, acetylhydrolase activity （AHA, the PAF degrading enzyme） and PAF receptor （PAF-R） transcripts in cirrhotic liver and hepatocellular carcinoma （HCC）. METHODS： Twenty-nine patients with HCC were enrolled in this study. Cirrhosis was present in fourteen patients and seven had no liver disease. Tissue PAF levels were investigated by a platelet-aggregation assay. Lyso- PAF was assessed after its chemical acetylation into PAR AHA was determined by degradation of [^3H]-PAE PLA2 levels were assessed by EIA. PAF-R transcripts were investigated using RT-PCR. RESULTS： Elevated amounts of PAF and PAF-R transcripts 1 （leukocyte-type） were found in cirrhotic tissues as compared with non-cirrhotic ones. Higher amounts of PAF and PAF-R transcripts 1 and 2 （tissue-type） were found in HCC tissues as compared with non-tumor tissues. PLA2, lyso-PAF and AHA levels were not changed in cirrhotic tissues and HCC. CONCLUSION： While the role of PAF is currently unknown in liver physiology, this study suggests its potential involvement in the inflammatory network found in the cirrhotic liver and in the angiogenic response during HCC.
文摘This review described origination, biosynthesis and functions of platelet-activating factor （PAF） in the reproductive system of mammals and human beings. The article mainly focused on biological roles of the phospholipid mediator in sperm fertilization and embryonic implantation. As an autocrine product of sperm and embryos, PAF markedly stimulates sperm motility and fertilization and serves as a capacitation factor in a ligand-receptor manner, After fertilization, embryo-derived PAF improves its own development, especially from fertilized ova to blastocyst stage and is thought to act as an embryo growth factor in the same manner as on sperm. Its mechanism of action was also clarified. At the end, it was presented some advances in its clinical application, followed by discussion of some issues possibly concerning in its current application.
文摘Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.
基金Supported by the Key Scientific and Technological Research Foundation of the National 863 Program,No.2003AA208106Medical Outstandard Foundation of Army,No.04J020
文摘AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCh for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS： Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels （P〈0.01, P〈0.01, P〈0.05, respectively）. Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats （P〈0.01）. Portal injection of PAF （1 g/kg WT） increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups （54% in control rats and 42% in cirrhotic rats）. Injection of the PAF antagonist BN52021 （5 mg/kg WT） decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION： The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in drrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.
