No abstract available.
Blood Platelets* ; Platelet Activating Factor* ; Progesterone*

Platelet-activation factor (PAF), one of the potent proinflammatory mediators, is produced from a large range of cells, including polymorphonuclear neutrophils, monocytes, and natural killer cells. To study the role of PAF in the pathogenesis of silicosis, we determined the PAF in silicotic patients and in healthy persons. The results showed that the concentration of PAF in the plasma of silicotic patients was significantly higher than that of healthy persons. Our in vitro experimental results showed that the total numbers of fibroblasts were markedly raised with added PAF from 0 to 1 μ g/ml. Adding 1 μ g/ml PAF significantly increased the total numbers of fibroblasts after culture for 48, 72, 96 hrs. Therefore, we suggest that PAF be possibly involved in the pathogenesis of silicosis. However, the mechanism remains to be further elucidated.
Platelet Activating Factor ; g <3> ; Pathogenesis ; /mL ; Effective

No abstract available.
Blood Platelets* ; Carnitine* ; Humans* ; Platelet Activating Factor* ; Spermatozoa*

To investigate the properties and mechanism of PAF and TNF on the synthesis of prostaglandin E2 in human amnion, primary monolayer culture method was used for human amnion cell incubation. Amnion cells were incubated with various concentrations of PAF or TNF in Ca++ containing medium for various duration. Then PG E2 concentrations were measured by RIA and analyzed for the effect of PAF and TNF on PG E2 production according to their doses and incubation time. To test the role of Ca++ in E2 production, Ca++ free medium, Ca++ -channel antagonist and cyclo-oxygenase inhibitor were substituted or added in incubation medium. Following results were obtained. The synthesis of PG E2 was significantly enhanced by PAF of 10(-6) mol/L. The TNF also stimulated PG E2 synthesis at concentration of 10(-6)g/ml. The maximal level in PAF(10-6mol/L)-stimulated release of PG E2 was observed after 16 hours in incubation. The TNF(10(-6)g/ml)-induced PG E2 release was maximal after 24 hours of incubation. Combined application of PAF and TNF produced positive effect in PG E2 production. PAF or TNF stimulated-PG E2 production in Ca++ -free media was much lower than that of Ca++ -containing media. The PAF-stimulated PG E2 release was significantly inhibited by Ca++ -channel antagonist but TNF-stimulated PG E2 release was not effected by Ca++ -channel antagonist or cyclo-oxygenase inhibitor. It is strongly suggested us that both PAF and TNF enhance PG E2 release by amnion cell, although Ca++ -channel opening is essential only for PAF stimulation.
Amnion* ; Blood Platelets* ; Dinoprostone* ; Humans* ; Platelet Activating Factor* ; Prostaglandin-Endoperoxide Synthases ; Tumor Necrosis Factor-alpha*

OBJECTIVE: The aim of this study is to determine whether any association exists between preeclampsia and the maternal serum level of nitric oxide (NO) and platelet activating factor (PAF). METHODS: NO concentrations were measured using Stuehr's method and PAF concentrations were measured with [3H]PAF scintillation proximity assay (SPA) system (Amersham Pharmacia Biotech). Data were analyzed with SAS windows version 6.12, with significance established at p<0.05. RESULTS: The mean (+/-SD) maternal serum concentrations of NO were significantly higher in the group with severe preeclampsia (5.535+/-0.343 ug/ml) and mild preeclampsia (5.891+/-0.481 ug/ml) than in the normotensive pregnancy group (2.036+/-0.744 ug/ml) (p<0.05). The mean (+/-SD) maternal serum concentrations of PAF were significantly higher in the group with severe preeclampsia (928.9+/-32.3 ng/ml) and mild preeclampsia (789.1+/-63.9 ng/ml) than in the normotensive pregnancy group (435.8+/-59.5 ng/ml) (p<0.05). The mean birth weight was lower in the mild and severe preeclampsia groups than in the normotensive pregnancy group (p<0.05). CONCLUSION: Maternal serum NO and PAF concentrations were more increased in preeclampsia than normotensive pregnancy group. NO may therefore serve as compensatory mechanism for vasoconstriction of preeclampsia and PAF as a marker for the risk of preeclampsia.
Birth Weight ; Blood Platelets* ; Nitric Oxide* ; Platelet Activating Factor* ; Pre-Eclampsia* ; Pregnancy ; Vasoconstriction

Erythrocytes are devoid of nuclei and mitochondria which are the crucial elements of apoptosis, so their programmed suicidal death is called eryptosis. Eryptosis is characterized by cell shrinkage, membrane blebbing, activation of proteases, and phosphatidylserine exposure. Prostaglandin E(2) (PGE(2)) activates nonselective cation channels that increase cytosolic Ca(2+) activity and platelet-activating factor (PAF) activates a sphingomyelinase which lead to formation of ceramide. Either can lead to membrane scrambling with subsequent phosphatidylserine exposure. Exposed phosphatidylserine is recognized by macrophages that engulf and degrade the injured cells. As such, eryptosis can clear the injured red blood cells and avoid the release of hemoglobin. The signaling of eryptosis includes PGE(2), cation channels, PAF, ceramide, protein kinase C, and in some instances, caspases. In this review, the PGE(2), PAF and protein kinase pathways, erythrocyte surface receptor-mediated effects, oxidative stress and caspase effects, the inhibitory factors of eryptosis and the clinical eryptosis-related diseases are discussed.
Apoptosis ; physiology ; Dinoprostone ; metabolism ; Erythrocytes ; metabolism ; physiology ; Humans ; Platelet Activating Factor ; metabolism ; Signal Transduction

Platelet-activating factor (PAF) is a unique and novel signaling phospholipid that has pleiotropic biologic properties in addition to platelet activation. Recent studies show that this novel compound plays a significant role in male reproduction and sperm function. PAF binds surface special receptors inducing the formation of inositol triphosphate (IP3) and diacylglycerol (DAG) and increasing intracellular calcium. The concentrations of sperm-derived PAF may help predict sperm motility and fertilization potential, which may serve as a valuable marker for assessing male fertility. Exogenous PAF can improve sperm motility, acrosome reaction and pregnancy rates in human intrauterine inseminations.
Fertilization in Vitro ; Humans ; Male ; Platelet Activating Factor ; pharmacology ; physiology ; Sperm Motility ; Spermatozoa ; drug effects ; physiology

BACKGROUND AND OBJECTIVES: The purpose of this study was to test whether platelet activating factor (PAF) impairs the mucociliary clearance function of the eustachian tube (ET)in dose dependent manner and PAF-antagonist can prevent the impairment of mucociliary function of the ET induced by PAF. RESULTS: Coomassie Brilliant Blue (CBB) dye transport time (DTT) in normal guinea pigs was 69 seconds. The dye transport time after the applications of normal saline, PAF 1, and 2 ug/ml of PAF into the bullae were 66, 74, and 157 seconds, respectively. The time was over 15 minutes when 4, 8, and 16 ug/ml of PAF were applied. The DTT were 62 seconds when the animals were pretreated with PAF-antagonist (WEB 2170). There were significant delay in the DTTs after treatment with 2, 4, 8, and 16 ug/ml of PAF. Histopathological examination of ETs from groups with significant delay in DTTs showed intact cilia, mucus plugs, increased inflammatory cells, and exfoliation of cells. CONCLUSION: This study demonstrated that PAF impaired mucociliary clearance function of the eustachian tube in dosedependent manner. This impairment of mucociliary clearance function was prevented by pre-treatment with PAF-antagonist. The findings of this study suggest that PAF plays an important role in the pathogenesis of otitis media by impairing eustachian tube clearance function.
Animals ; Cilia ; Eustachian Tube* ; Guinea Pigs* ; Guinea* ; Mucociliary Clearance* ; Mucus ; Otitis Media ; Platelet Activating Factor

OBJECTIVE: To investigate the relationship between platelet activating factor (PAF) and occurrence of hepatorenal syndrome (HRS). METHODS: A total of 57 cases of patients with liver cirrhosis or hepatitis gravis were enrolled. The serum concentrations of PAF, lipopolysaccharide (LPS) and prothrombin activity (PTA), total bilirubin, and serum creatinine were detected in patients combined with HRS and in patients without HRS in hospital at the term. The correlations among the PAF, LPS, and the function of liver and kidney were analyzed. RESULTS: The concentrations of PAF and LPS in the patients combined with HRS were significantly higher than those patients without HRS. There were linear correlations between the PAF and LPS level, the total bilirubin level and PAF level, the PAF level and serum creatinine level. CONCLUSION The PAF associates with the occurrence of HRS. The PAF may mediate the occurrence of HRS induced by LPS. The PAF level may forecast whether patients with liver failure will take place HRS.
Biomarkers ; metabolism ; Female ; Hepatorenal Syndrome ; metabolism ; Humans ; Male ; Platelet Activating Factor ; metabolism

OBJECTIVETo investigate the expression changes and regulation of pituitary adenylate cyclase-activating polypeptide (PACAP) mRNA in corpus luteum during pregnancy.

METHODSPregnant rats' ovaries were collected at different time points. The techniques of RT-PCR and in situ hybridization were used to observe expression changes of PACAP mRNA in rat ovaries during pregnancy. To further explore the regulation mechanism of PACAP mRNA expression in corpus luteum, luteal cells were cultured in vitro. Immature (25 - 28 days old) female Sprague-Dawley rats were injected subcutaneously with 50IU pregnant mare serum gonadotrophin (PMSG), and 25IU human chorionic gonadotrophin (hCG) 48 h later, to induce follicular development and luteum formation. On day 6 after hCG administration (the day of hCG administration was the first day), the rats were killed by guillotine and the ovarian luteal cells were collected. After incubation for 24 h, luteal cells were administration with various factors for 24 h. And then expression changes of PACAP mRNA in luteal cells after administration with different factors were detected by RT-PCR, and radioimmunoassay was used to analyze progesterone levels.

RESULTSWith the development of pregnancy, the expression of PACAP mRNA increased gradually, reached the peak at pregnancy 19 d, and then decreased. Compared with control group, platelet activating factor (PAF), forskolin and PMA could obviously stimulate PACAP mRNA expression in luteal cells which were cultured with corresponding factors for 24 h. At the same time, progesterone levels in culture media were also elevated.

CONCLUSIONPACAP, acting as a local ovary regulator, was closely related to the maintenance of medium-term and late pregnancy. PAF could directly stimulate PACAP mRNA expression in luteal cells, and protein kinase C (PKC) and protein kinase A (PKA) signal pathways could both participate in this process.

Animals ; Cells, Cultured ; Corpus Luteum ; metabolism ; Female ; Pituitary Adenylate Cyclase-Activating Polypeptide ; genetics ; metabolism ; Platelet Activating Factor ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley