Consumption of plant extract supplement reduces platelet activating factor-induced platelet aggregation and increases platelet activating factor catabolism: a randomised, double-blind and placebo-controlled trial.

Platelet-activating factor (PAF) is a potent mediator of inflammation that plays a crucial role in atherosclerosis. The purpose of this study was to evaluate the effect of a dietary supplement containing mainly plant extracts on PAF actions and metabolism in healthy volunteers. A double-blind, placebo-controlled, 8 weeks' duration study was performed. Healthy volunteers were randomly allocated into the supplement or the placebo group and fifty-eight of them completed the study. The supplement contained plant extracts (Aloe gel, grape juice, Polygonum cuspidatum) and vitamins. The activities of PAF metabolic enzymes: the two isoforms of acetyl-CoA:lyso-PAF acetyltransferase, cytidine 5'-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-cholinephosphotransferase) and platelet-activating factor-acetylhydrolase (PAF-AH) in leucocytes and lipoprotein associated phospholipase-A2 in plasma were measured along with several markers of endothelial function. Platelet aggregation against PAF, ADP and thrombin receptor activating peptide was measured in human platelet-rich plasma by light transmission aggregometry. No difference was observed on soluble vascular cell adhesion molecule-1, sP-selectin and IL-6 levels at the beginning or during the study period between the two groups. Concerning PAF metabolism enzymes' activity, no difference was observed at baseline between the groups. PAF-AH activity was only increased in the supplement group at 4 and 8 weeks compared with baseline levels. In addition, supplement consumption led to lower platelet sensitivity against PAF and ADP compared with baseline levels. However, a trial effect was only observed when platelets were stimulated by PAF. In conclusion, supplementation with plant extracts and vitamins ameliorates platelet aggregation primarily against PAF and secondarily against ADP and affects PAF catabolism by enhancing PAF-acetylhydrolase activity in healthy subjects.

[ON THE ISSUE OF SELECTION OF COAGULANTS UNDER ADP-INDUCED IMPEDANCE TEST OF AGGREGATION OF THROMBOCYTES IN PATIENTS WITH CHRONIC MYELO-PROLIFERATIVE TUMORS].

The evaluation was implemented concerning impact of anticoagulants used during venous blood sampling, on aggregation of thrombocytes and acetylsalicylic acid effect in vitro in 111 patients with suspicion to chronic myelo-proliferative tumors and 16 healthy volunteers. The vacutainers (Becton Dickinson) with 3.2% citrate, with heparin (Becton Dickinson) and S-Monovette system (Sarstedt AG & Co) with recombinant herudin were applied. The analysis of aggregation was implemented using the technique of impedance in whole blood before and after preliminary incubation of blood samples with acetylsalicylic acid effect in 0.1 mM concentration. The induction was implemented by ATP in final concentration of 5 mkM. It is demonstrated that ATP-induced amplitude of aggregation under application of heparin and hirudin is significantly higher in comparison with its level in samples of citrate blood. At that, acetylsalicylic acid effect paradoxically increases amplitude of aggregation in samples with heparin but not in samples with citrate or hirudin. The application of hirudin permits evaluating impact of acetylsalicylic acid effect both at aggregation and disaggregation component of thrombocyte functions under erythrocytosis and thrombocytosis and can be recommended as a preferable approach in testing individual sensitivity of patients to acetylsalicylic acid effect.

Roles of BN52021 in platelet-activating factor pathway in inflammatory MS1 cells.

AIM: To determine the effects of BN52021 on platelet-activating factor receptor (PAFR) signaling molecules under lipopolysaccharide (LPS)-induced inflammatory conditions in MS1 cells. METHODS: MS1 cells (a mouse pancreatic islet endothelial cell line) were grown in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 2 mmol/L glutamine and 100 µg/mL penicillin/streptomycin in 5% CO2 at 37 °C. After growth to confluency in media, the cells were processed for subsequent studies. The MS1 cells received 0, 0.1, 1 and 10 µg/mL LPS in this experiment. The viability/proliferation of the cells induced by LPS was observed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. Apoptosis and necrosis of the cells under the inflammatory condition described previously were observed using Hoechst 33342-propidium iodide staining. Adenylate cyclase (AC), phospholipase A2 (PLA2), phospholipase Cß (PLCß), protein tyrosine kinase (PTK), G protein-coupled receptor kinases (GRK) and p38-mitogen-activated protein kinase (p38 MAPK) mRNA in the PAFR signaling pathway were measured by real-time polymerase chain reaction. The protein expression level of phosphorylated AC (p-AC), phosphorylated PLA2 (p-PLA2), phosphorylated PTK (p-PTK), phosphorylated p38 MAPK (p-p38 MAPK), PLCß and GRK was measured using Western blotting analysis. RESULTS: The activity of MS1 cells incubated with different concentrations of LPS for 6 h decreased significantly in the 1 µg/mL LPS group (0.49 ± 0.10 vs 0.67 ± 0.13, P < 0.05) and 10 µg/mL LPS group (0.44 ± 0.10 vs 0.67 ± 0.13, P < 0.001), but not in 0.1 µg/mL group. When the incubation time was extended to 12 h (0.33 ± 0.05, 0.32 ± 0.03 and 0.25 ± 0.03 vs 0.69 ± 0.01) and 24 h (0.31 ± 0.01, 0.29 ± 0.03 and 0.25 ± 0.01 vs 0.63 ± 0.01), MS1 cell activity decreased in all LPS concentration groups compared with the blank control (P < 0.001). BN52021 significantly improved the cell activity when its concentration reached 50 µmol/L compared with the group that received LPS treatment alone, which was consistent with the results obtained from fluorescence staining. The mRNAs levels of AC (4.02 ± 0.14 vs 1.00 ± 0.13), GRK (2.63 ± 0.03 vs 1.00 ± 0.12), p38 MAPK (3.87 ± 0.07 vs 1.00 ± 0.17), PLA2 (3.31 ± 0.12 vs 1.00 ± 0.12), PLCß (2.09 ± 0.08 vs 1.00 ± 0.06) and PTK (1.85 ± 0.07 vs 1.00 ± 0.11) were up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up-regulated mRNAs including AC (2.35 ± 0.13 vs 3.87 ± 0.08), GRK (1.17 ± 0.14 vs 2.65 ± 0.12), p38 MAPK (1.48 ± 0.18 vs 4.30 ± 0.07), PLCß (1.69 ± 0.10 vs 2.41 ± 0.13) and PLA2 (1.87 ± 0.11 vs 2.96 ± 0.08) were significantly suppressed by BN52021 except for that of PTK. The level of p-AC (1.11 ± 0.12 vs 0.65 ± 0.08), GRK (0.83 ± 0.07 vs 0.50 ± 0.03), PLCß (0.83 ± 0.16 vs 0.50 ± 0.10) and p-p38 MAPK (0.74 ± 0.10 vs 0.38 ± 0.05) was up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up-regulated proteins, including p-AC (0.65 ± 0.15 vs 1.06 ± 0.14), GRK (0.47 ± 0.10 vs 0.80 ± 0.06), PLCß (0.47 ± 0.04 vs 0.80 ± 0.19) and p-p38 MAPK (0.30 ± 0.10 vs 0.97 ± 0.05), was significantly suppressed by BN52021, but p-PLA2 and p-PTK protein level were not suppressed. CONCLUSION: BN52021 could effectively inhibit LPS-induced inflammation by down-regulating the mRNA and protein levels of AC, GRK, p38 MAPK, PLA2 and PLCß in the PAFR signaling pathway.

[Changes of prostaglandin D2,carboxypeptidase A3 and platelet activating factor in guinea pig in anaphylactic shock].

OBJECTIVE: To detect the changes of leukotriene E4(LTE4), prostaglandin D2(PGD2), carboxypeptidase A3(CPA3) and platelet activating factor (PAF) in guinea pigs died from anaphylactic shock. METHODS: Guinea pigs were used for establishing anaphylactic shock models. The levels of LTE4, PGD2 and CPA3, and PAF were detected in urine, plasma, and brain tissues with ELISA kit, respectively. The significant biomarkers were selected comparing with control group. The changes of PGD2, CPA3 and PAF in the guinea pigs at time zero, 12 and 24 hours after death were observed and compared respectively. The effect of platelet activating factor acetylhydrolase (PAF-AH) to PAF in guinea pig brain was examined and compared. RESULTS: There were no statistically differences of LTE4 levels in urine observed between experimental group and control group. The levels of CPA3, PGD2 and PAF in the experimental group were significantly higher than that in the control group at 0 h. The levels of PAF at 12 and 24 hours after anaphylactic shock were significantly higher than that in the control group. The levels of PAF decreased significantly after pretreatment with PAF-AH. CONCLUSION: LTE4 in urine cannot be selected as a biomarker to determine the anaphylactic shock. PGD2 and CPA3 in plasma, and PAF in brain tissue may be used as biomarkers to determine the anaphylactic shock. PAF-AH may be potentially useful for clinical treatment of anaphylactic shock.

Intrinsic platelet reactivity before P2Y12 blockade contributes to residual platelet reactivity despite high-level P2Y12 blockade by prasugrel or high-dose clopidogrel. Results from PRINCIPLE-TIMI 44.

It was the objective of this study to determine whether the intrinsic platelet response to adenosine diphosphate (ADP) before thienopyridine exposure contributes to residual platelet reactivity to ADP despite high level P2Y12 blockade by prasugrel (60 mg loading dose [LD]), 10 mg daily maintenance dose [MD]) or high-dose clopidogrel (600 mg LD, 150 mg daily MD). High residual platelet function during clopidogrel therapy is associated with poor clinical outcomes. It remains unknown whether the relationship between platelet reactivity prior to treatment with clopidogrel (300 mg LD, 75 mg daily MD) and residual on-treatment platelet reactivity is maintained after more potent P2Y12 inhibition. PRINCIPLE-TIMI 44 was a randomised, double-blind, two-phase crossover study of prasugrel compared with high-dose clopidogrel in 201 patients undergoing cardiac catheterisation for planned percutaneous coronary intervention. ADP-stimulated platelet-monocyte aggregates, platelet surface P-selectin and platelet aggregation were measured pre-treatment, during LD (6 h and 18-24 h) and MD (15 d). Correlations of pre-treatment to on-treatment values were determined by Spearman rank order. Prasugrel resulted in greater platelet inhibition than high-dose clopidogrel for each measure. However, for both drugs, pre-treatment reactivity to ADP predicted 6 h, 18-24 h and 15 day reactivity to ADP (correlations 0.24-0.62 for platelet-monocyte aggregates and P-selectin). In conclusion, a patient's intrinsic platelet response to ADP before exposure to thienopyridines contributes to residual platelet reactivity to ADP despite high level P2Y12 blockade with high-dose clopidogrel or even higher level P2Y12 blockade with prasugrel. Patients who are hyper-responsive to ADP pre-treatment are more likely to be hyper-responsive to ADP on-treatment, which may be relevant to therapeutic strategies.

Two new ginkgolides from the leaves of Ginkgo biloba.

Two new diterpenoid compounds, ginkgolide P(1) and ginkgolide Q(2), were isolated from the leaves of Ginkgo biloba L. Their structures were elucidated by various spectroscopic methods, and the structure of 1 was further confirmed by X-ray crystallographic analysis. The activities of the compounds were evaluated against platelet aggregation induced by platelet activating factor (PAF), and the preliminary structure-activity relationship was also discussed.

Dimeric prenylated C6-C3 compounds from the stem bark of Illicium oligandrum.

Three new dimeric prenylated C6-C3 compounds, namely, illicidiones A (1), B (2), and C (3), were isolated from the stem bark of Illicium oligandrum. The structure and absolute configuration of these compounds were determined by extensive spectroscopic and chemical analyses, including NMR, modified Mosher method, and single-crystal X-ray study. Compounds 1-3 exhibited weak anti-inflammatory activities.

[Cerebrovascular and antiaggregative effects of GABA-docosahexaenoyldopamine conjugate].

The effects of GABA - docosahexaenoyldopamine (DHED) conjugate on the cerebral haemodynamics and thrombocyte aggregation were evaluated and compared to these of docosahexaenoyldopamine alone. The GABA - DHED conjugate was shown to significantly enhance the cerebral circulation in rats with a model of global transient cerebral ischemia, as compared to the intact animals. Administered alone, DHED increased the blood supply of both intact and ischemic brains to an equal extent. The GABA-DHED conjugate demonstrated the antiaggregative activity, but the effect was less expressed than that of DHED alone.

Anti-platelet-activating factor effects of highly active antiretroviral therapy (HAART): a new insight in the drug therapy of HIV infection?

Platelet-activating factor (PAF) is a potent inflammatory mediator, which seems to play a role in the pathogenesis of several AIDS manifestations such as AIDS dementia complex, Kaposi's sarcoma, and HIV-related nephropathy. PAF antagonists have been studied in these conditions with promising results. In order to examine the possible interactions between PAF and antiretroviral therapy, we studied the effect of nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors against PAF biological activities and its basic biosynthetic enzymes dithiothreitol-insensitive PAF-cholinephosphotransferase (PAF-CPT) and lyso-PAF-acetyltransferase (Lyso-PAF-AT), as well as its main degradative enzyme PAF-acetylhydrolase, of human mesangial cell line (HMC). We also studied the effect of several backbones and highly active antiretroviral therapy (HAART) regimens against PAF activity. Among the drugs tested, several inhibited PAF-induced platelet aggregation in a concentration-depended manner, with tenofovir, efavirenz, and ritonavir exhibiting the higher inhibitory effect. In addition, when these drugs were combined in backbones and HAART regimens based on American antiretroviral therapy proposals, they also synergistically exhibited an inhibitory effect against PAF-induced platelet aggregation. Several of these drugs have also inhibited in vitro microsomal PAF-CPT activity, and concentrations of lopinavir-r or tenofovir-DF (similar to their IC(50) against PAF-induced platelet aggregation) exhibited the same effect against PAF-CPT and Lyso-PAF-AT when added in the cell medium of cultured HMC. In addition, in naïve patients treated with one of the most potent anti-PAF HAART regimens (efavirenz/emtricitabine/tenofovir-DF) for a period of 1 month, a significant reduction of the specific activity of PAF-CPT of washed human leukocytes of these patients was also observed, compared with its levels before the HAART treatment. These promising results need to be further studied and confirmed by additional in vivo tests in order to optimize HAART efficacy.

[Losartan for the correction of thrombocyte activity in patients suffering from arterial hypertension with metabolic syndrome].

The aim of the study was to evaluate therapeutic effects of losartan on intravascular thrombocyte activity (ITA) in patients suffering from arterial hypertension with metabolic syndrome (MS). The subjects of the study were 35 patients administered losartan 50 mg a day for 4 months. The dynamics of the following parameters were evaluated: anthropometric parameters, blood lipids, lipid peroxidation in blood plasma and thrombocytes, the anti-oxidative protection of the liquid part of blood and platelets, and ITA. Student criterion was used for statistical analysis. In patients with AH and MS losartan had a positive effect on peroxidation syndrome and optimized ITA. To maintain the positive effects, prolonged administration of losartan is needed. In order to lower body mass in AH patients with MS losartan should be used in combination with non-drug means.

Epac/Rap1 pathway regulates microvascular hyperpermeability induced by PAF in rat mesentery.

Experiments in cultured endothelial cell monolayers demonstrate that increased intracellular cAMP strongly inhibits the acute permeability responses by both protein kinase A (PKA)-dependent and -independent pathways. The contribution of the PKA-independent pathways to the anti-inflammatory mechanisms of cAMP in intact mammalian microvessels has not been systematically investigated. We evaluated the role of the cAMP-dependent activation of the exchange protein activated by cAMP (Epac), a guanine nucleotide exchange factor for the small GTPase Rap1, in rat venular microvessels exposed to the platelet-activating factor (PAF). The cAMP analog 8-pCPT-2'-O-methyl-cAMP (O-Me-cAMP), which stimulates the Epac/Rap1 pathway but has no effect on PKA, significantly attenuated the PAF increase in microvessel permeability as measured by hydraulic conductivity (Lp). We also demonstrated that PAF induced a rearrangement of vascular endothelial (VE)-cadherin seen as numerous lateral spikes and frequent short breaks in the otherwise continuous peripheral immunofluorescent label. Pretreatment with O-Me-cAMP completely prevented the PAF-induced rearrangement of VE-cadherin. We conclude that the action of the Epac/Rap1 pathway to stabilize cell-cell adhesion is a significant component of the activity of cAMP to attenuate an acute increase in vascular permeability. Our results indicate that increased permeability in intact microvessels by acute inflammatory agents such as PAF is the result of the decreased effectiveness of the Epac/Rap1 pathway modulation of cell-cell adhesion.

[Sorption and contact-activating properties of the <> anastomosis zone: effect of suture material (communication II)].

The authors have carried out a comparative analysis of the interaction between two types of suture material with blood components, as well as studied the effect of heparin-mediated modification on the sorption and contact-activating processes in the zone of the anastomosis. The blood-compatible properties of the latter was assesses in vitro. It was determined that by minute 120 of the contact with blood, the largest amount of protein is had been absorbed by the anastomoses performed using the Prolene thread - 112 microg/cm2. Heparin-mediated modification made it possible to dramatically decrease the amount of the absorbed proteins. On the anastomoses performed with TiNi, additional treatment with heparin lead to an inconsiderable decrease in the protein amount. When identifying the absorbed proteins, we revealed dependence on the type of the suture material and modification with heparin. After a 60-minute contact with blood in the area of the anastomosis made with TiNi, absorbed were: albumin, immunoglobulins A, G, and transferrin. When using the Prolene thread, fibrinogen was noted to join. Additional heparinization exerted a favourable effect on the sorption processes in the area of the anastomosis wherein predominantly albumin and immunoglobulins A and G are predominantly absorbed. The parameters of the peak values and the rate of blood platelet aggregation were minimal in the area of the anastomoses done with TiNi with an additional treatment with heparin.

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

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.

Synergism in the repression of COX-2- and TNFalpha-induction in platelet activating factor-stressed human neural cells.

Platelet activating factor (PAF; beta-acetyl-gamma-O-hexadecyl-l-alpha-phosphatidylcholine) triggers a rapid pro-inflammatory gene expression program in primary cultures of human neural (HN) cells. Two genes and gene products consistently induced after PAF treatment are the cytosoluble prostaglandin synthase cycloooxygenase-2 (COX-2) and the pro-apoptotic tumor necrosis factor alpha (TNFalpha). Both of these mediators are associated with the activation of inflammatory signaling, neural cell dysfunction, apoptosis and brain cell death, and both have been found to be up-regulated after brain injury in vivo. In this study we investigated the effects of the non-halogenated synthetic glucocorticoid budesonide epimer R (BUDeR), the novel PAF antagonist LAU-0901, and the electron spin trap and free radical scavenger phenyl butyl nitrone (PBN), upon early COX-2 and TNFalpha gene activation and prostaglandin E(2) (PGE(2)) release in PAF-stressed primary HN cells. The data indicate that these three biochemically unrelated classes of inflammatory repressors act synergistically in modulating PAF-induced up-regulation of COX-2, TNFalpha, and PGE(2) by quenching oxidative stress or inflammatory signaling, resulting in increased HN cell survival. These, or analogous classes of compounds, may be useful in the design of more effective combinatorial pharmacotherapeutic strategies in the treatment of complex neuro-inflammatory disorders.

[Comparative evaluation of the influence of sulfhydryl and phosphate ACE inhibitors on thrombocyte aggregation in patients suffering from atrerial hypertension with metabolic syndrome].

The purpose of the study was to compare the influence of two ACE inhibitors--captopril, a sulfhydryl one, and fozinopril, a phosphate one--on the aggregation activity of thrombocytes in patients suffering from arterial hypertension (AH) with metabolic syndrome (MS). Sixty-nine patients suffering from AH with MS were examined; 36 patients were administered captopril during 16 weeks, while 33 patients were treated with fozinopril during the same period of time. Changes in anthropometric parameters, blood lipid spectrum, lipid peroxidation in blood plasma and thrombocytes, and the antioxidative protection of liquid part of blood and platelets, as well as the aggregation activity of thrombocytes were assessed. The data received were processed using Student criterion and system multifactor analysis. The study shows that the use of fozinopril in patients with AH and metabolic syndrome attenuates peroxidation syndrome and optimizes thrombocyte aggregation. Prolonged fozinopril application will stabilize the achieved effect. Captopril did not have a positive effect on the parameters under study. In conclusion, fozinopril should be applied in combination with non-drug means to lower body weight in patients suffering from AH with MS.

Role of platelet-activating factor in pneumolysin-induced acute lung injury.

OBJECTIVE: Acute respiratory failure is a major complication of severe pneumococcal pneumonia, characterized by impairment of pulmonary microvascular barrier function and pulmonary hypertension. Both features can be evoked by pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae. We hypothesized that platelet-activating factor (PAF) and associated downstream signaling pathways play a role in the PLY-induced development of acute lung injury. DESIGN: Controlled, ex vivo laboratory study. SUBJECTS: Female Balb/C mice, 8-12 wks old. INTERVENTIONS: Ventilated and blood-free-perfused lungs of wild-type and PAF receptor-deficient mice were challenged with recombinant PLY. MEASUREMENTS AND MAIN RESULTS: Intravascular PLY, but not the pneumolysoid Pd-B (PLY with a Trp-Phe substitution at position 433), caused an impressive dose-dependent increase in pulmonary vascular resistance and increased PAF in lung homogenates, as detected by reversed-phase high-performance liquid chromatography coupled to tandem mass spectrometry. The pressor response was reduced in lungs of PAF receptor-deficient mice and after PAF receptor blockade by BN 50730. PLY and exogenous PAF increased thromboxane B2 in lung effluate, and thromboxane receptor inhibition by BM 13505 diminished the pressor response to PLY. Differential inhibition of intracellular signaling steps suggested significant contribution of phosphatidylcholine-specific phospholipase C and protein kinase C and of the Rho/Rho-kinase pathway to PLY-induced pulmonary vasoconstriction. Unrelated to the pulmonary arterial pressor response, microvascular leakage of PLY was diminished in lungs of PAF receptor-deficient mice as well. CONCLUSIONS: PAF significantly contributed to PLY-induced acute injury in murine lungs. The PAF-mediated pressor response to PLY depends on thromboxane and on the downstream effectors phosphatidylcholine-specific phospholipase C, protein kinase C, and Rho-kinase.

[Biological action and clinical application of shark liver oil]. / Mechanizm dzialania i zastosowanie kliniczne oleju z watroby rekina.

Fish oils contain several active compounds that modify cell activity and influence various functions of the body. Shark liver oils are rich in alkylglycerols and squalene, but contain relatively low amounts of n-3 polyunsaturated fatty acids. Alkylglycerols may control immune response possibly throw modification of platelet activating factor (PAF) and diacylglycerol (DAG) production. Squalene enhances antigen presentation and induction of inflammatory response. Moreover, alkylglycerols and squalene have antitumour activity, that is possibly based on different mechanisms, ie., induction of apoptosis of neoplastic cells, suppression of signal transduction, inhibition of angiogenesis and promoting of transmembrane transport of cytotoxic agents. Shark liver oil has been found to be useful in treatment of conditions resulted from inadequate immune response, and in adjunctive treatment of several types of cancer.

The effects of Gingko biloba extract on acetic acid-induced colitis in rats.

BACKGROUND/AIMS: Gingko biloba is an antioxidant substance which has antagonistic activity on platelet-activating factor. We aimed to investigate the antioxidant effect and the histopathologic changes caused by Gingko biloba on acetic acid-induced colitis. METHODS: Totally 22 rats were divided into three groups. Group 1 (n=7) served as the control group. Group 2 (n=7) and Group 3 (n=8) were given 2 ml/day of 4% acetic acid by intracolonic instillation for three days. Gingko biloba (100 mg/kg) was then given only to Group 3 intraperitoneally for three days. Oxidative stress was assessed by determinate tissue and serum malondialdehyde (MDA) levels, and colonic damage was assessed by histologic examination. RESULTS: Depth of necrosis, extent of necrosis, degree of inflammation, extent of inflammation, fibrosis and total histologic scores in Group 2 were significantly higher than in the control group (p<0.05). The same parameters were lower in Group 3 versus Group 2, but the difference was not significant. Tissue and serum MDA levels in Group 2 were significantly higher than Group 1 (p<0.01 and 0.05, respectively). Again, the same parameters in Group 3 were lower than in Group 2, but the difference was not significant statistically. CONCLUSIONS: Gingko biloba did not significantly affect histopathological and oxidative stress parameters in experimental colitis.

In vivo antiatherogenic properties of olive oil and its constituent lipid classes in hyperlipidemic rabbits.

BACKGROUND AND AIM: The consumption of olive oil has been associated with lower incidence of cardiovascular disease in the Mediterranean countries. This may be due in part to the action of platelet-activating factor (PAF) antagonists which we have previously demonstrated to be present in olive oil. In order to assess the in vivo effects of olive oil lipids and PAF in the development of atherosclerosis, the effects of diet supplementation with olive oil (OO), olive oil polar lipid extract (OOPLE) and olive oil neutral lipid extract (OONLE) were studied in rabbits fed a cholesterol-enriched diet. METHODS AND RESULTS: Rabbits were fed for 45 days with atherogenic diet (Group A) supplemented with OO (Group B), OOPLE (Group C) or OONLE (Group D). Lipoprotein profiles, plasma in vitro oxidation, blood PAF levels, PAF-induced platelet aggregation and PAF-acetylhydrolase (PAF-AH) activity, were measured on day 0 and 45. Atherosclerotic lesions formed in the aortic wall and wall elasticity were assessed on day 45. Changes in lipid profile were in accordance with previous studies. Blood PAF levels were higher in group A and decreased in group D on day 45. In rabbits fed an atherogenic diet (Group A) blood PAF and PAF-AH increased, atherosclerotic lesions formed and the elasticity of vessel walls declined. In animals fed olive oil (Group B) or OOPLE (Group C) blood PAF-AH increased, platelet aggregation was attenuated, less oxidation occurred in plasma, lesion thickness was reduced and vessel walls retained elasticity. Most of these beneficial changes were not seen in animals fed OONLE (Group D) although blood PAF and plasma oxidation were lower. CONCLUSIONS: The antiatherogenic effects of OO result from OOPLE. The beneficial effect of these factors is linked to PAF metabolism and proaggregant activity.