Preparation and analysis of immunocompetence of recombinant fusion protein of the immunodominant region in chlamydial protease-like activity factor from Chlamydophila pneumoniae and its application in serodiagnosis

To clone the gene coding the immunodominant region in the chlamydial protease-like activity factor （CPAF） from Chlaroydophila pneumoniae, to analyze immunoeoropetenee of the expressed protein, and to evaluate its value in serodiagnosis, the CPAF immunodominant region gene was amplified, ligated into a pGEX6p-2 vector, and then the expressed recombinant protein was purified with glutathione Stransferase （GST） agarose gel FF after renaturation, then identified by SDS-PAGE and Western blot. A new indirect ELISA was developed with the purified protein as coating antigen. The immunogenicity of the recombinant protein was evaluated by immunization to New Zealand rabbits, and its immunoreactivity was analyzed by reacting with anti-C, pneumoniae antibody. 300 clinical sera samples were respectively detected by mieroimmunofluorescenee （MIF） as reference method and the indirect ELISA, and the difference between the two methods was analyzed. Cross-reactivity against Chlamydia trachomatis was investigated with the indirect ELISA to detect anti-C, trachomatis positive antisera. The results indicated that a 51.3 kDa recombinant protein was obtained. Western blot assay proved that the recombinant protein could merely specifically react with human anti- C. pneurnoniae antisera. The titers of the specific IgG antibodies in the immunized New Zealand rabbits were above 1 ： 16 000. Anti- C. pneumoniae IgG positive and negative reference sera were detected with the indirect ELISA, and the concordance rate of negative and positive results were both 100% （40/40）. The sensitivity and specificity of the indirect ELISA in comparison with MIF were 93.8% （45/48） and 100% （252/252） separately by detecting 300 clinical sera samples, and the concordance rate between the two methods was 99.0%. No cross reaction against C. trachomatis was found with the indirect ELISA to detect anti-C, trachomatis positive antisera. In conclusion, the prepared recombinant protein of the CPAF immunodominant region shows excellent immunocompetence and can be used to develop a new indirect ELISA as a method to detect anti-C, pneumoniae antibody for diagnosis of C. pneumoniae infection.

Effects of Buyang Huanwu decoction and Astragalus mongholicus on platelet activating factor receptor activity in rabbits in vitro

BACKGROUND: The pharmacological action of traditional Chinese medicine compound is the comprehensive effect of the various ingredients, and the interactions of various ingredients are closely correlated with the final effect. In order to reveal the compatibility mechanism of BHD's prescription in treating and preventing ischemic cerebrovascular disease, we needed explore the effect and relation of ingredients in the prescription. OBJECTIVE: To observe the effect of Buyang Huanwu decoction (BHD) and Astragalus mongholicus on the activity of platelet activating factor receptor (PAFR) in the platelet of rabbits in vitro, and investigate the mechanism of Astragalus mongholicus. DESIGN: A decomposed recipes study. SETTING: Guangzhou University of Traditional Chinese Medicine. MATERIALS: Five New Zealand rabbits, weighing 2-3 kg, both sexes, were used. BHD was composed of Sheng Huang Qi 120 g, Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g, Hong Hua 3 g. The prescription for activating blood circulation consisted of Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g and Hong Hua 3 g. The prescription for invigorating qi consisted of 120 g Sheng Huang Qi. The prepared herbal pieces were purchased from the traditional Chinese medicine Dispensary of Foshan Second People's Hospital, and appraised by Professor Xu from Science of Chinese Materia Medica College, Guangzhou University of Traditional Chinese Medicine. 3H-PAF was supplied by Amersham Co., Ltd. (specific activity: 6. 475 TBq/mmol; batch number: 200402); PAF standard by Biomol Co., Ltd. (batch number: P1318V). METHODS: The experiments were carried out in the Laboratory of Nuclear Medicine, Guangzhou University of Traditional Chinese Medicine from September to December 2004. ① Injections of BHD, prescriptions for activating blood circulation and invigorating qi were prepared by the decoction and alcohol sedimentation technique. Rabbit common carotid artery blood (40 mL) was drawn via intubation to prepare platelet suspension of (0.8-1.0)×1010 L-1. ② Determination of 3H-PAF and washed PAFR binding: The general combination tube (T) contained washed platelet-rich plasma (WPRP) 380 μL + 3H-PAF (0.35 nmol/L)10 μL+distilled water 5 μL; The nonspecific binding tube (P) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+cold PAF (1 μmol/L) 5 μL; The sample tube (Y) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+experimental medicine (injection of BHD, prescriptions for activating blood circulation or invigorating qi) 5 μL. The test was conducted for three times for each sample in the same way as mentioned above. The samples were shaken on the oscillator for 30 s, then bathed at 25 ℃ for 40 minutes, and the reaction was terminated with cold Tris buffer containing 0.1% BSA, multichannel cell detachment separator was used for vacuum suction to filter the separated free 3H-PAF, and the filter paper was washed with cold Tris buffer for four times, then dried in the baking oven (80 ℃) for 1 hour, and placed in xylol liquid scintillator, and the radioactivity was determined automatically by the liquid scintillation detector. The mean of the three parallel tubes was calculated. The specific binging inhibition rate was calculated: SBIR=[(T-Y)/(T-P)]×100%]. ③ Univariate analysis of variance was conducted. And for comparison of each paired groups, the q test was adopted. MAIN OUTCOME MEASURES: Effect of BHD whole prescription, prescriptions for activating blood circulation and invigorating qi on the specific binding inhibition rate of 3H-PAF and PAFR. RESULTS: BHD, prescriptions for activating blood circulation and invigorating qi were all able to inhibit the specific binding of 3H-PAF to PAFR, the specific blinding inhibition rates were (45.90±7.50)%, (97.90±1.84)% and (26.75±2.48)%, respectively, and there were significant differences between every two groups (P < 0.01). CONCLUSION: Single Astragalus mongholicus (120 g) can inhibit the specific blinding of PAFR in the platelet of the rabbit with 3H-PAF, but the combination of Astragalus mongholicus with the drugs for activating blood circulation in BHD can significantly decrease the inhibiting action of the latter on PAFR activity of the platelet, reflecting the combined mechanism of 'removing blood stasis without injuring the vital qi' in BHD.

β-Arrestin-2 enhances endoplasmic reticulum stress-induced glomerular endothelial cell injury by activating transcription factor 6 in diabetic nephropathy

BACKGROUND Glomerular endothelial cell(GENC)injury is a characteristic of early-stage diabetic nephropathy(DN),and the investigation of potential therapeutic targets for preventing GENC injury is of clinical importance.AIM To investigate the role ofβ-arrestin-2 in GENCs under DN conditions.METHODS Eight-week-old C57BL/6J mice were intraperitoneally injected with streptozotocin to induce DN.GENCs were transfected with plasmids containing siRNA-β-arrestin-2,shRNA-activating transcription factor 6(ATF6),pCDNA-β-arrestin-2,or pCDNA-ATF6.Additionally,adeno-associated virus(AAV)containing shRNA-β-arrestin-2 was administered via a tail vein injection in DN mice.RESULTS The upregulation ofβ-arrestin-2 was observed in patients with DN as well as in GENCs from DN mice.Knockdown ofβ-arrestin-2 reduced apoptosis in high glucose-treated GENCs,which was reversed by the overexpression of ATF6.Moreover,overexpression ofβ-arrestin-2 Led to the activation of endoplasmic reticulum(ER)stress and the apoptosis of GENCs which could be mitigated by silencing of ATF6.Furthermore,knockdown ofβ-arrestin-2 by the administration of AAV-shRNA-β-arrestin-2 alleviated renal injury in DN mice.CONCLUSION Knockdown ofβ-arrestin-2 prevents GENC apoptosis by inhibiting ATF6-mediated ER stress in vivo and in vitro.Consequently,β-arrestin-2 may represent a promising therapeutic target for the clinical management of patients with DN.

Lipopolysaccharide-induced cerebral inflammatory damage and the therapeutic effect of platelet activating factor receptor antoganist

Objective To investigate lipopolysaccharide （LPS） induced acute cerebral inflammatory damage and the therapeutic effect of ginkgolide B （BN52021）. Methods Thirty Sprague-Dawley rats were randomly divided into 3 groups （n = 10 for each group）： Control group, Model group and Treatment group （treated with BN52021）. LPS were injected into the fourth ventricle of rat to make a neuroinflammatory murine model. Morris water maze was used to detect the learning and memory ability of rats; changes of synapse number and subcellular ultrastructures were observed under a transmission electron microscope; OX-42 positive microglia in the brain was detected by immunohistochemical method. Results The average escape latency in the Treatment group were significantly shortened than that in the Model group; and the percentage of swimming distance traveled in platform quadrant accounting for total distance increased markedly. The rough endoplasmic reticulum and polyribosomes in the Treatment group were more than that in the Model group, but the number of synapses seemed to have no obvious change. The number of OX-42 positive microglia in the Treatment group decreased markedly than that in the Model group, and the grey density of OX-42-positive cells increased significantly. Conclusion LPS can induce inflammatory damages to the brain, but the damage could be antagonized by BN52021. Platelet activating factor receptor antagonist may offer an effective therapy for neurodegeneration diseases.

Significance of platelet activating factor receptor expression in pancreatic tissues of rats with severe acute pancreatitis and effects of BN52021

AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgolide B). METHODS:Wistar male rats were randomly assigned to the negative control group (NC group),SAP model group (SAP group),and BN52051-remedy group (BN group),and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h,3 h,6 h,12 h,and 24 h) (n=10 in each). PT-PCR and Western blot methods were used to detect PAF-RmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected. RESULTS:Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase,and the pathological ratings in BN group at 3 h,6 h,and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19,9.15 ± 0.55 vs 5.55 ± 0.36,10.10 ± 0.65 vs 6.72 ± 0.30,P < 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups,which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04,P < 0.05),and decreased gradually later. There were significant differences at each time point except 1 h and 2 h,when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10,0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09,0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10,0.20 ± 0.06 or 0.20± 0.04 vs 0.43 ± 0.09,P < 0.05),whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA. There were significant differences at each time point except 1 h,when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02,1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03,1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09,1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10,P < 0.05),whereas there was no significant difference between the BN group and the SAP group. CONCLUSION:PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.

Platelet-activating factor in cirrhotic liver and hepatocellular carcinoma

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.

Effect of Buyang Huanwu Decoction on Platelet Activating Factor Content in Arterial Blood Preand Post-Arterial Thrombosis in Rats

To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the medicine group treated with BHD, the control group with dexamethasone liquid, and the blank group with distilled water. Oral administration was given for 14 consecutive days, once daily. Model of arterial thrombosis was established in the animals 2 hours after final medication, the blood content of PAF, dry weight (DW) and occlusion time (OT) of thrombus, and dry weight of thrombus/body weight (TW/BW) ratio were observed. Results indicated that BHD could markedly lower the arterial blood content of PAF after thrombosis, increase the OT of thrombus, reduce the dry weight of thrombus and the TW/BW ratio (P

Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl_4-induced liver cirrhosis

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.

Synthesis of platelet-activating factor and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis

AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.

Elevated Platelet Activating Factor Level in Ischemia-Related Arrhythmia and Its Electrophysiological Effect on Myocardium

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.

Expression of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 in normal and malignant tissues of gastrointestinal tract

AIM： To provide the expression profile of serine protease SNC19/matriptase and its inhibitor hepatocyte growth factor activator inhibitor type 1 （HAI-1） in normal and malignant tissues of gastrointestinal tract at mRNA level for further study on their correlations with tumor progression and metastasis. METHODS： Total RNAs were prepared from 37 samples of colorectal cancer tissues, 40 samples of gastric cancer tissues, and their adjacent normal tissues. The expression of SNC19/matriptase and HAI-1 in these samples was detected by real-time fluorescent quantitative PCR using glyceraldehyde-3-phosphate dehydrogenase as internal standard, and the clinical significance for the correlation with clinicopathological parameters was evaluated. RESULTS： In gastric cancer tissues the expression of HAI-1 and SNC19/matriptase was significantly lower than that in the corresponding adjacent normal tissues （Z = -3.280, P= 0.006; Z= -4.651, P= 0.000）. HAI-1：SNC19/matriptase ratio showed no difference between normal and malignant tissues （P〉0.05）. Analysis of clinicopathological parameters showed decreased expression of HAI-1 and HAI-1：SNC19/ matriptase ratio associated with stage Ⅲ/Ⅳ gastric tumors as compared to stage Ⅰ/Ⅱ ones （Z= -2.140, P= 0.031; Z = -2.155, P = 0.031）, and with lymph node-positive gastric cancer tissues as compared to lymph node-negative ones （Z = -2.081, P = 0.036; Z= -2.686, P = 0.006）. The expression of SNC19/matriptase had no relationship with stages and lymph node metastasis （P〉0.05）. The expression of HAI-1 and HAI-1：SNC19/matriptase ratio increased in well-differentiated gastric cancer tissues, but there was no statistical significance （P〉0.05）. The difference of SNC19/matriptase expression was not significant in gastric cancer tissues of different histological differentiation status （P〉0.05）. In colorectal cancer tissues, the expression of HAI-1 and SNC19/matriptase was also markedly lower than that in their adjacent normal tissues （Z= -3.100, P = 0.002; Z= -2.731, P = 0.006）, whereas HAI-1：SNC19/matriptase ratio showed no difference. Decreased expression of HAI-1 was associated with increased invasive depth and lymph node metastasis, but there was no statistical significance （P〉0.05）. The difference of SNC19/matriptase expression and HAI-1： SNC19/matriptase ratio was not significant in different stages and different lymph node metastasis status （P〉0.05）. The expression of SNC19/matriptase, HAI-1 or HAI-1： SNC19/matriptase ratio showed no difference in colorectal cancer tissues of different histological differentiation status （P〉0.05）. CONCLUSION： The expressions of SNC19/matriptase and its inhibitor HAI-1 are decreased in gastrointestinal cancer tissues compared to their normal counterparts, and the decreased expression of HAI-1 may correlate with invasion and lymph node metastasis. The possible mechanisms involved need to be further investigated.

Aberrant activation of nuclear factor of activated T cell 2 in lamina propria mononuclear cells in ulcerative colitis

AIM:To investigate the role of nuclear factor of activated T cell 2(NFAT2),the major NFAT protein in peripheral T cells,in sustained T cell activation and intractable inflammation in human ulcerative colitis(UC). METHODS:We used two-dimensional gel-electrophoresis, immunohistochemistry,double immunohistochemical staining,and confocal microscopy to inspect the expression of NFAT2 in 107,15,48 and 5 cases of UC, Crohn's disease(CD),non-specific colitis,and 5 healthy individuals,respectively. RESULTS:Up-regulation with profound nucleo- translocation/activation of NFAT2 of lamina propria mononuclear cells(LPMC)of colonic mucosa was found specifically in the affected colonic mucosa from patients with UC,as compared to CD or NC(P<0.001,Kruskal- Wallis test).Nucleo-translocation/activation of NFAT2 primarily occurred in CD8+T,but was less prominent in CD4+T cells or CD20+B cells.It was strongly associated with the disease activity,including endoscopic stage (τ=0.2145,P=0.0281)and histologic grade(τ=0.4167, P<0.001). CONCLUSION:We disclose for the first time the nucleo-translocation/activatin of NFAT2 in lamina propria mononuclear cells in ulcerative colitis.Activation of NFAT2 was specific for ulcerative colitis and highly associated with disease activity.Since activation of NFAT2is implicated in an auto-regulatory positive feedback loop of sustained T-cell activation and NFAT proteins play key roles in the calcium/calcineurin signaling pathways,our results not only provide new insights into the mechanism for sustained intractable inflammation,but also suggest the calcium-calcineurin/NFAT pathway as a new therapeutic target for ulcerative colitis.

Hepatic stellate cells may be potential effectors of platelet activating factor induced portal hypertension

AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/μg in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/μg. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/μg. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.

Qingyi decoction attenuates intestinal epithelial cell injury via the calcineurin/nuclear factor of activated T-cells pathway

BACKGROUND Recent studies have demonstrated that dysfunction of the intestinal barrier is a significant contributing factor to the development of severe acute pancreatitis(SAP).A stable intestinal mucosa barrier functions as a major anatomic and functional barrier,owing to the balance between intestinal epithelial cell(IEC)proliferation and apoptosis.There is some evidence that calcium overload may trigger IEC apoptosis and that calcineurin(CaN)/nuclear factor of activated Tcells(NFAT)signaling might play an important role in calcium-mediated apoptosis.AIM To investigate the potential mechanisms underlying the therapeutic effect of Qingyi decoction(QYD)in SAP.METHODS A rat model of SAP was created via retrograde infusion of sodium deoxycholate.Serum levels of amylase,tumor necrosis factor(TNF-α),interleukin(IL)-6,D-lactic acid,and diamine oxidase(DAO);histological changes;and apoptosis of IECs were examined in rats with or without QYD treatment.The expression of the two subunits of CaN and NFAT in intestinal tissue was measured via quantitative realtime polymerase chain reaction and western blotting.For in vitro studies,Caco-2 cells were treated with lipopolysaccharide(LPS)and QYD serum,and then cell viability and intracellular calcium levels were detected.RESULTS Retrograde infusion of sodium deoxycholate increased the severity of pancreatic and intestinal pathology and the levels of serum amylase,TNF-α,and IL-6.Both the indicators of intestinal mucosa damage(D-lactic acid and DAO)and the levels of IEC apoptosis were elevated in the SAP group.QYD treatment reduced the serum levels of amylase,TNF-α,IL-6,D-lactic acid,and DAO and attenuated the histological findings.IEC apoptosis associated with SAP was ameliorated under QYD treatment.In addition,the protein expression levels of the two subunits of CaN were remarkably elevated in the SAP group,and the NFATc3 gene was significantly upregulated at both the transcript and protein levels in the SAP group compared with the control group.QYD significantly restrained CaN and NFATc3 gene expression in the intestine,which was upregulated in the SAP group.Furthermore,QYD serum significantly decreased the LPS-induced elevation in intracellular free Ca^(2+)levels and inhibited cell death.CONCLUSION QYD can exert protective effects against intestinal mucosa damage caused by SAP and the protective effects are mediated,at least partially,by restraining IEC apoptosis via the CaN/NFATc3 pathway.

A new high-performance AC/DC power factor correction switching converter based on one-cycle control technology and active floating-charge technology

A new family of converters,high-performance AC/DC power factor correction(PFC) switching converters with one-cycle control technology and active floating-charge technology,was derived and experimentally verified.The topology of a single-phase CCM and DCM Boost-PFC switching converter was also analyzed.Its operating prniciples and control methods were expounded.Based on these,a new type of AC/DC switching converter circuits for PFC combined with one-cycle control technology was presented herein.The proposed AC/DC switching converter significantly helps improve the converter efficiency and its power factor value.

Sequential expression of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor in rat hippocampal neurons after fluid percussion injury

Traumatic brain injury causes gene expression changes in different brain regions. Occurrence and development of traumatic brain injury are closely related, involving expression of three factors, namely cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. However, little is known about the correlation of these three factors and brain neuronal injury. In this study, primary cultured rat hippocampal neurons were subjected to fluid percussion injury according to Scott’s method, with some modifications. RT-PCR and semi-quantitative immunocytochemical staining was used to measure the expression levels of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. Our results found that cyclooxygenase-2 expression were firstly increased post-injury, and then decreased. Both mRNA and protein expression levels reached peaks at 8 and 12 hours post-injury, respectively. Similar sequential changes in glutamate receptor 2 were observed, with highest levels mRNA and protein expression at 8 and 12 hours post-injury respectively. On the contrary, the expressions of platelet activating factor receptor were firstly decreased post-injury, and then increased. Both mRNA and protein expression levels reached the lowest levels at 8 and 12 hours post-injury, respectively. Totally, our findings suggest that these three factors are involved in occurrence and development of hippocampal neuronal injury.

Creation of reversed phase high-performance liquid chromatographic technique to assay platelet-activating factor

Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.

Aberrant activation of latent transforming growth factor-β initiates the onset of temporomandibular joint osteoarthritis

There is currently no effective medical treatment for temporomandibular joint osteoarthritis(TMJ-OA) due to a limited understanding of its pathogenesis. This study was undertaken to investigate the key role of transforming growth factor-β(TGF-β)signalling in the cartilage and subchondral bone of the TMJ using a temporomandibular joint disorder(TMD) rat model, an ageing mouse model and a Camurati–Engelmann disease(CED) mouse model. In the three animal models, the subchondral bone phenotypes in the mandibular condyles were evaluated by μCT, and changes in TMJ condyles were examined by TRAP staining and immunohistochemical analysis of Osterix and p-Smad2/3. Condyle degradation was confirmed by Safranin O staining, the Mankin and OARSI scoring systems and type X collagen(Col X), p-Smad2/3 a and Osterix immunohistochemical analyses. We found apparent histological phenotypes of TMJ-OA in the TMD, ageing and CED animal models, with abnormal activation of TGF-βsignalling in the condylar cartilage and subchondral bone. Moreover, inhibition of TGF-β receptor I attenuated TMJ-OA progression in the TMD models. Therefore, aberrant activation of TGF-β signalling could be a key player in TMJ-OA development.

DNA-dependent activator of interferon-regulatory factors inhibits hepatitis B virus replication

AIM： To investigate whether DNA-dependent activator of interferon-regulatory factors （DAI） inhibits hepatitis B virus （HBV） replication and what the mechanism is. METHODS： After the human hepatoma cell line Huh7 was cotransfected with DAI and HBV expressing plas- mid, viral protein （HBV surface antigen and HBV e an- tigen） secretion was detected by enzyme-linked immu- nosorbent assay, and HBV RNA was analyzed by real- time polymerase chain reaction and Northern blotting, and viral DNA replicative intermediates were examined by Southern blotting. Interferon regulatory factor 3 （IRF3） phosphorylation and nuclear translocation were analyzed via Western blotting and immunofluorescence staining respectively. Nuclear factor-KB （NF-KB） activity induced by DAI was detected by immunofluorescence staining of P65 and dual luciferase reporter assay. Tran- swell co-culture experiment was performed in order to investigate whether the antiviral effects of DAI were dependent on the secreted cytokines. RESULTS： Viral protein secretion was significantly re- duced by 57% （P 〈 0.05）, and the level of total HBV RNA was reduced by 67% （P 〈 0.05）. The viral core particle-associated DNA was also dramatically down- regulated in DAI-expressing Huh7 cells. Analysis of involved signaling pathways revealed that activation of NF-KB signaling was essential for DAI to elicit antivi- ral response in Huh7 cells. When the NF-KB signaling pathway was blocked by a NF-KB signaling suppressor （I~：B^-SR）, the anti-HBV activity of DAI was remarkably abrogated. The inhibitory effect of DAI was indepen- dent of IRF3 signaling and secreted cytokines. CONCLUSION： This study demonstrates that DAI can inhibit HBV replication and the inhibitory effect is asso- ciated with activation of NF-KB but independent of IRF3 and secreted cytokines.

Receptor activator of nuclear factorκB ligand/osteoprotegerin axis and vascular calcifications in patients with chronic kidney disease

Vascular calcifications are commonly observed in patients with chronic kidney disease （CKD） and contri-bute to the excessive cardiovascular morbidity and mortality rates observed in these patients populations. Although the pathogenetic mechanisms are not yet fully elucidated, recent evidence suggests a link between bone metabolism and the development and progression of vascular calcifications. Moreover, accumulating data indicate that receptor activator of nuclear factor κB ligand/osteoprotegerin axis which plays essential roles in the regulation of bone metabolism is also involved in extra-osseous bone formation. Further studies are required to establish the prognostic significance of the above biomarkers as predictors of the presence and severity of vascular calcifications in CKD patients and of cardiovascular morbidity and mortality. Moreover, randomized clinical trials are needed to clarify whether inhibition of osteoclast activity will protect from vascular calcifcations.