6-ketoprostaglandin-f1-alpha and Pulmonary-Embolism

Cydonia oblonga Miller (COM) is traditionally used in Uyghur medicine for the prevention of cardiovascular disease. The present study is designed to explore the effects of COM extracts on models and markers of thrombosis and related biomarkers.. 20, 40, 80 mg/kg/day COM aqueous extracts and 5mg/kg/day aspirin, orally for 14 days were compared to untreated controls in mice on bleeding and clotting times, using the tail cutting and glass slide methods and for death rates in collagen-epinephrine pulmonary thrombosis, thrombolysis in vitro and euglobulin lysis time (ELT). In rats, common carotid artery FeCl3-induced thrombus and inferior vena cava thrombosis occlusion time, plasma concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandine F1α (6-keto-PGF1α) were measured.. Compared to controls, COM extracts dose-dependently prolonged bleeding by 2.17, 2.78 and 3.63 times, vs. aspirin 2.58, and the clotting time by 1.44, 2.47 and 2.48 times, vs. aspirin 1.91. COM reduced pulmonary embolus mortality by 27, 40 and 53%, vs. 47% for aspirin. COM dose-dependently increased thrombolysis by 45, 55 and 63%, vs. 56% for aspirin, and shortened ELT to 71, 61 and 43%, vs. 43% for aspirin. In rats, venous occlusion time was prolonged. Arterial and venous thrombus weights were dose-dependently reduced in COM groups. TXB2 decreased and 6-keto-PGF1α increased with COM and aspirin, with an association between 6-keto-PGF1α/TXB2 and arterial or venous thrombus weight for all products, and for occlusion time with COM but not for aspirin.. We confirm the experimental effects of COM on hemostasis and thrombosis. Further exploration of putative clinical effects appear justified.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Coagulation; Cardiovascular Agents; Carotid Artery Thrombosis; Chlorides; Collagen; Epinephrine; Ferric Compounds; Fibrinolysis; Hemostasis; Male; Mice, Inbred ICR; Phytotherapy; Plant Extracts; Plant Leaves; Pulmonary Embolism; Rats, Wistar; Rosaceae; Thromboxane B2; Vena Cava, Inferior; Venous Thrombosis

The aim of this study was to evaluate the effect of BM-573 [N-terbutyl-N'-[2-(4'-methylphenylamino)-5-nitro-benzenesulfonyl]urea], a dual thromboxane A2 synthase inhibitor and receptor antagonist, on the hemodynamic response to acute pulmonary embolism. Six anesthetized pigs were infused with placebo (placebo group) and compared with six other pigs receiving a continuous infusion of BM-573 (BM group). Pulmonary embolization with 0.3 g/kg autologous blood clots was carried out 30 min after the start of the infusion. Right ventricular pressure-volume loops were recorded using a conductance catheter, and end-systolic ventricular elastance was periodically assessed by varying right ventricular preload. Pulmonary vascular properties were studied by use of a four-element windkessel model. Hemodynamic data, including assessment of right ventricular-arterial coupling, were collected at baseline and every 30 min for 4 h. Blood samples were collected to assess gas exchange, thromboxane A2, and prostacyclin plasma levels and to evaluate platelet aggregation. Mean pulmonary arterial pressure in the placebo group increased significantly more than in the BM group, mainly because of an additional increase in pulmonary vascular resistance. Arterial and end-systolic ventricular elastances increased also more in the placebo group, whereas right ventricular efficiency decreased. BM-573 prevented both platelet aggregation induced by U-46619 (9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F2alpha) or by arachidonic acid, and thromboxane A2 overproduction, whereas prostacyclin liberation was preserved. Oxygenation, however, was not significantly improved. We conclude that in this animal model of acute pulmonary embolism, infusion of BM-573 reduced pulmonary vasoconstriction. As a result, right ventricular-vascular coupling values were maintained at a maximal efficiency level.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Blood Coagulation; Epoprostenol; Female; Hemodynamics; Male; Platelet Aggregation; Pulmonary Embolism; Receptors, Thromboxane; Sulfonylurea Compounds; Swine; Thromboxane A2; Thromboxane B2; Thromboxane-A Synthase

To explore the changes of the platelet function and serum anticardiolipin antibody (ACA) in patients with pulmonary thromboembolism (PTE).. Forty-eight patients with PTE diagnosed by spiral computed tomographic pulmonary angiography (CTPA) were included as the trial group, while 20 person in which PTE was excluded served as the control group. P-selectin, and GPIIb/IIIa expressed on platelets were measured by flow cytometry, and plasma TXB(2), 6-Keto-PGF1alpha, vWF, D-dimer and serum ACA were measured by ELISA and the changes of these parameters were compared 1 week later.. In the trial group, the levels of P-selectin, GPIIb/IIIa, TXB(2), vWF, D-dimer and T/K were significantly higher than those in the control group (P < 0.01). But the plasma level of 6-Keto-PGF1alpha in the patients with PTE was significantly lower than that in the control group (P < 0.01). The levels of ACA-IgG and ACA-IgA were significantly higher than those in the control group (P < 0.01). After therapy the level of 6-Keto-PGF1alpha was significantly higher than that before therapy (P < 0.01), and other parameters were significantly lower than those before therapy (P < 0.01). P-selectin, GPIIb/IIIa and vWF were positively correlated with D-dimer (P < 0.01).. Endothelium damage, platelet activation and hypercoagulation combined with fibrinolytic activation occur in patients with PTE.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Aged; Aged, 80 and over; Antibodies, Anticardiolipin; Anticoagulants; Blood Platelets; Endothelium, Vascular; Female; Humans; Male; Middle Aged; P-Selectin; Platelet Glycoprotein GPIIb-IIIa Complex; Pulmonary Embolism; Thromboxane B2

To evaluate the effects of lupus anticoagulant (LA) on pulmonary thromboembolism (PTE).. Thirty-eight patients with PTE (17 massive and 21 submassive) and 30 healthy adults were studied. Russell's viper venom time (RVVT) was used to examine the ratio of LA (LAR), and a colorimetric method was used to detect the activity of plasma protein C (PC:A) and radioimmunoassay (RIA) was employed to measure the level of plasma thromboxane B(2) (TXB(2)) and 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha).. Compared with the normal group, LAR, TXB(2) and TXB(2)/6-keto-PGF1alpha showed significant increase in the massive PTE and the submassive PTE groups (P < 0.01), and the levels were higher in the massive group than in the submassive group (P < 0.01). Both groups showed significant decrease in PC:A and 6-keto-PGF1alpha compared with the normal group (P < 0.01).. LA can increase TXB(2)/6-keto-PGF1alpha and decrease PC:A in patients with PTE. It is suggested that there may be an association between the increase of LAR and the presence of PTE.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; C-Reactive Protein; Female; Humans; Lupus Coagulation Inhibitor; Male; Middle Aged; Prostaglandins; Pulmonary Embolism; Radioimmunoassay; Thromboembolism; Thromboxane B2

To investigate the role of blood vessel active substances, such as endothelin-1 (ET-1), thromboxane B(2) (TXB(2)), and 6-keto-prostaglandin F(1alpha) (6-K-PGF(1alpha)) in a rabbit model of acute pulmonary embolism induced by echinococus granulous cyst.. Catheters were placed into the femoral artery and the femoral vein. Saline, fresh clear cyst fluid or sand containing cyst fluid in a volume of 2 ml/kg were infused through the femoral vein catheter. Changes of ET-1, TXB(2) and 6-K-PGF(1alpha) were measured; PaO(2), PaCO(2), pH, MAP, heart rate, and respiration rate were recorded; and radionuclide lung perfusion scan and the change of heart and lung pathology were studied.. The changes of the studied parameters were not remarkable in the saline treated animals (P > 0.05). TXB(2) and 6-K-PGF(1alpha) were elevated in the cyst fluid treated animals (P < 0.05). PaO(2), PaCO(2), and MAP declined in the clear cyst fluid group (P < 0.05), but their changes were more significant in animals treated with sand containing cyst fluid. Radionuclide lung perfusion scan showed radioactivity defect or attenuation. Histological examination of the lungs revealed diffuse alveolar damage.. Sand containing cyst fluid caused a more severe disease in this rabbit model of acute pulmonary embolism, suggesting that it played an important role in the induction of lung damage.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Gas Analysis; Blood Pressure; Echinococcosis; Endothelin-1; Female; Lung; Male; Myocardium; Pulmonary Embolism; Rabbits; Radionuclide Imaging; Thromboxane B2

Myocardial ischemia plays a central role in the development of right ventricular failure after acute pulmonary embolism. This study investigates whether pulmonary mediators act specifically on coronary tone and cardiac contractile function in acute pulmonary microembolization and whether such effects are altered in the case of early systemic atherosclerosis. We employ a novel model of serial perfusion in which an isolated rabbit heart is perfused with the effluent of the same animal's isolated lung.. Controlled experiment using isolated organs.. Experimental laboratory.. Male New Zealand White rabbits (controls). Age-matched, male Watanabe rabbits (hypercholesterolemic, development of accelerated atherosclerosis).. Seven isolated control and seven isolated Watanabe hearts were perfused with the saline effluent of the same animal's isolated lung. After the assessment of the baseline data, the lungs were gradually embolized with glass beads measuring 100 microm in diameter to induce an increase in mean pulmonary arterial pressure from 6 to 8 mm Hg, at baseline, up to 25 mm Hg.. Pulmonary embolization to 25 mm Hg evoked a coronary constriction, measured as coronary flow decrease to 89 +/- 7% of the baseline value in controls. In the Watanabe group, coronary constriction was significantly enhanced, compared with controls, with coronary flow decreasing to 76 +/- 6% of the baseline value. In both groups, coronary constriction was followed by a deterioration in cardiac contractile performance. This cardiodepression was significantly deeper in Watanabe hearts with respect to both maximum ventricular pressures and maximum rates of pressure development and decline. Coronary constriction and cardiodepression were prevented by coronary infusion of the nonselective endothelin antagonist PD-145065, the endothelinA antagonists A-127722 and BQ-123, and the endothelin-converting enzyme inhibitor phosphoramidon. Concentration of big endothelin in pulmonary effluent increased from 5.6 +/- 0.3 pmol/L in controls and 5.6 +/- 0.2 pmol/L in the Watanabe group, at baseline, to 8.8 +/- 0.4 pmol/L in controls and 8.9 +/- 0.4 pmol/L in the Watanabe group, at 25 mm Hg pulmonary arterial pressure. Endothelin was not detectable at any time during the experiment in pulmonary effluent. The coronary gradient, calculated as a difference in concentration between coronary and pulmonary effluent, was negative for big endothelin and positive for endothelin in both groups.. We have demonstrated that an increase in pulmonary release of big endothelin occurs during lung embolism, which, in turn, results in coronary constriction and consequent cardiodepression. This action of big endothelin is based on its local coronary conversion into endothelin. In addition, coronary endothelial dysfunction, attributed to early systemic atherosclerosis, was shown to represent a specific risk factor in these events.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arteriosclerosis; Aspartic Acid Endopeptidases; Atrasentan; Coronary Circulation; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Endothelins; Endothelium, Vascular; Glycopeptides; In Vitro Techniques; Male; Metalloendopeptidases; Myocardial Contraction; Oligopeptides; Peptides, Cyclic; Protein Precursors; Pulmonary Embolism; Pyrrolidines; Rabbits; Thromboxane B2; Vasoconstriction

Bilateral cemented arthroplasty (BCA) in anaesthetized mongrel dogs produces particulate fat and marrow embolism of the lung. Methylprednisolone sodium succinate (MPSS) has been advocated for post-traumatic fat embolism to prevent acute lung injury. We used the BCA procedure to produce acute fat and marrow embolism, and tested the efficacy of MPSS (30 mg.kg-1) in preventing physiological and pathological markers of acute lung injury. Dogs (n = 6) pre-treated with MPSS demonstrated similar acute increases in pulmonary artery pressure (PAP) within one minute of BCA (17.8 +/- 7.3 mmHg) as the untreated (control n = 7) dogs (18.6 +/- 12.6). Pulmonary vascular resistance (PVR) increased to the same degree in both groups (455 +/- 323 and 319 +/- 137 dyne.sec.cm-5) and PaO2 decreased by 18.3 +/- 6.4 mmHg in the control group as opposed to 12.4 +/- 7.7 mmHg in the MPSS group within five minutes of BCA. Circulating arterial and mixed venous plasma concentrations of thromboxane B2 (TxB2) increased within one minute of BCA in both groups with no increase in the transpulmonary gradient. Arterial plasma 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) increased (0.91 +/- 0.29 ng.ml-1 and 0.87 +/- 0.43 ng.ml-1) in both groups one minute after BCA. Mixed venous 6-keto PGF1 alpha plasma concentration also increased, but a significant transpulmonary 6-keto PGF1 alpha gradient was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Bone Cements; Bone Marrow; Dogs; Embolism, Fat; Femur; Hip Prosthesis; Hypertension, Pulmonary; Lung; Methylprednisolone; Oxygen; Pulmonary Artery; Pulmonary Embolism; Thromboxane B2; Time Factors; Vascular Resistance

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Cardiac Output; Dogs; Embolism, Fat; Methylprednisolone; Methylprednisolone Hemisuccinate; Premedication; Pulmonary Circulation; Pulmonary Embolism; Thromboxane B2; Vascular Resistance

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Aged; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Pulmonary Embolism; Serotonin; Thromboxane B2

The effect of glass-bead microemboli (diameter 100 micron, range 77-125 micron) in the absence of fibrinolysis inhibition on pulmonary hemodynamics and microvascular permeability was determined in anesthetized, microfilaria-free dogs acutely prepared for the collection of lung lymph. Pulmonary vascular resistance, pulmonary capillary pressure (Pc), lymph flow (QL), and the ratio of lymph (CL) to plasma (Cp) protein concentrations were measured after 0.2 (n = 4), 0.4 (n = 6), or 0.6 (n = 3) g/kg beads. In all cases, emboli increased resistance and QL severalfold (P less than 0.05), while CL/Cp remained unchanged. In part, the increase in QL could be attributed to an increase in Pc compared with control (12.4 +/- 2.2 vs. 6.7 +/- 0.6 mmHg, P less than 0.05). Furthermore, since the solvent-drag reflection coefficient (sigma f) for total proteins approaches the osmotic reflection coefficient (sigma d) at high QL, sigma d was estimated under these conditions with sigma f approximately equal to sigma d approximately equal to 1 - (CL/Cp)min. The sigma d was decreased (P less than 0.05) after 0.4 and 0.6 g/kg beads to 0.55 +/- 0.03 and 0.50 +/- 0.07, respectively, when compared with that in control lungs (sigma d = 0.62 +/- 0.02; Parker et al., Circ. Res. 48: 549-561, 1981). A pore-stripping analysis demonstrated that after emboli the pulmonary endothelial barrier could be described by a population of small (80 A) and large (350 A) pores. However, the number of large to small pores was 1:1,195, compared with 1:195 in control lungs, suggesting an increased contribution of extra-alveolar vessels upstream of the emboli.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Blood Proteins; Capillaries; Capillary Permeability; Dogs; Endothelium, Vascular; Fibrinolysis; Glass; Lung; Lymph; Lymphatic System; Lymphocytes; Microspheres; Neutrophils; Proteins; Pulmonary Embolism; Thromboxane B2; Vascular Resistance

To assess the role of intracellular adenosine 3',5'-cyclic monophosphate (cAMP), we tested the effects of dibutyryl cAMP (DBcAMP), an analogue of cAMP, on lung injury induced by pulmonary air embolism in awake sheep with chronic lung lymph fistula. We infused air (1.23 ml/min) in the pulmonary artery for 2 h in untreated control sheep. In DBcAMP-pretreated sheep DBcAMP was infused (1 mg/kg bolus and 0.02 mg.kg-1.min-1 constantly for 5 h); after 1 h from beginning of DBcAMP administration the air infusion was started. After the air infusion, pulmonary arterial pressure (Ppa) and lung lymph flow rate (Qlym) significantly increased in both groups. DBcAMP-pretreated sheep showed significantly lower responses in Qlym (2.7 X base line) compared with untreated control sheep (4.6 X base line); however, Ppa, left atrial pressure, and lung lymph-to-plasma protein concentration ratio were not significantly different between the two groups. Although plasma and lung lymph thromboxane B2 and 6-ketoprostaglandin F1 alpha concentrations increased significantly during the air infusion, DBcAMP-pretreated sheep showed significantly lower responses. Thus DBcAMP infusion attenuated pulmonary microvascular permeability induced by air embolism. We conclude that pulmonary vascular permeability is in part controlled by the intracellular cAMP level.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Bucladesine; Capillary Permeability; Embolism, Air; Lymph; Pulmonary Artery; Pulmonary Circulation; Pulmonary Embolism; Sheep; Thromboxane B2

We compared pulmonary vascular responses with thrombin-induced pulmonary microembolism in awake sheep pretreated with ibuprofen or meclofenamate. Control sheep with lung lymph fistulas (n = 6) were challenged with 80 U/kg of alpha-thrombin, the native enzyme. Two groups of similarly prepared sheep received the cyclooxygenase inhibitors, ibuprofen (n = 4) or meclofenamate (n = 4), before the thrombin challenge. Thrombin-induced pulmonary microembolism in control sheep increased pulmonary lymph flow and lymph protein clearance (lymph flow X lymph-to-plasma protein concentration ratio). These lymph changes were associated with sustained increases in mean pulmonary arterial pressure (Ppa) and pulmonary vascular resistance (PVR) and a decrease in circulating neutrophil count. The steady-state pulmonary hemodynamic and lymph responses to thrombin persisted after cyclooxygenase inhibition with meclofenamate, although the increases in pulmonary lymph flow and lymph protein clearance were delayed. In contrast, ibuprofen reduced pulmonary lymph flow, lymph protein clearance, Ppa, and PVR responses. Neutrophil count in control and meclofenamate groups remained below base line after thrombin, whereas neutrophil count returned to base line in the ibuprofen group within 90 min after thrombin. Ibuprofen resulted in a greater decrease in vitro neutrophil adherence to pulmonary endothelium induced by serum generated by clotting whole blood with alpha-thrombin as compared with meclofenamate. Results indicate that ibuprofen attenuates the increases in Ppa and PVR and markedly attenuates the increase in pulmonary transvascular protein clearance after thrombin. The protective effect of ibuprofen may be due to reduction of neutrophil sequestration in lung.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Cell Adhesion; Cyclooxygenase Inhibitors; Drug Interactions; Ibuprofen; Lymphatic System; Lymphocyte Activation; Meclofenamic Acid; Neutrophils; Pulmonary Circulation; Pulmonary Embolism; Sheep; Superoxides; Thrombin; Thromboxane B2; Vascular Resistance

Effects of a new imidazole derivative, sodium 4-[alpha-hydroxy-5-(imidazolyl)-2-methylbenzyl]-3,5-dimethyl benzoate dihydrate (Y-20811), on thromboxane (TX) production and platelet aggregation were investigated. Y-20811 inhibited TX synthetase (IC50 = 2.2 X 10(-8) M) and platelet aggregation induced by arachidonic acid (AA) in human, guinea pig and rabbit platelets in vitro. Administered orally to rabbits, Y-20811 at a dose of 1 mg/kg decreased serum TXB2 concomitant with increasing 6-keto PGF1 alpha and at a dose of 3 mg/kg inhibited AA-induced platelet aggregation, in both cases for at least 48 hours. Y-20811 (0.3 mg/kg/day) administered to rabbits for 7 days decreased serum TXB2 levels by 50-90% during the medication, and these levels were restored to initial values 3 days after withdrawal of the drug. At a dose of 1 mg/kg Y-20811 protected rabbits against death induced by AA (2 mg/kg). These results indicate that Y-20811 is a selective and long-lasting TX synthetase inhibitor and an anti-aggregating agent useful in preventing thrombotic disorders.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Arachidonic Acids; Blood Platelets; Guinea Pigs; Humans; Imidazoles; In Vitro Techniques; Kinetics; Male; Microsomes; Platelet Aggregation; Platelet Count; Pulmonary Embolism; Rabbits; Seminal Vesicles; Sheep; Species Specificity; Thromboxane B2; Thromboxane-A Synthase; Thromboxanes

We investigated the effects of OKY-046 and OKY-1580, thromboxane A2 (TxA2) synthetase inhibitors, on plasma levels of 6-keto PGF1 alpha and TxB2 in anesthetized dogs with experimentally induced air embolism. The percentage increase of tracheal pressure induced by room air infusion was suppressed significantly by premedication with OKY-046. The percentage increase of pulmonary artery blood pressure was suppressed significantly by premedication with OKY-046 compared to that in control group. By room air infusion after the premedication with OKY-046 and OKY-1580, systemic artery blood pressure did not show any significant changes. Plasma 6-keto PGF1 alpha level showed a marked increase by an intravenous infusion of room air, and such an increase became more predominant by the premedication with OKY-046 and OKY-1580. On the other hand, plasma TxB2 level showed a marked increase by an intravenous infusion of room air, and such an increase became less predominant by the premedication with OKY-046 and OKY-1580. These results may suggest that OKY-046 and OKY-1580 are not only TxA2 synthetase inhibitors but also PGI2 synthetase accelerators and are useful drugs for treatment and prevention of thromboembolism.

Topics: 6-Ketoprostaglandin F1 alpha; Acrylates; Anesthesia; Animals; Blood Pressure; Dogs; Embolism, Air; Methacrylates; Pulmonary Artery; Pulmonary Embolism; Thromboxane B2; Thromboxane-A Synthase

Release of prostaglandins (PG's) after experimental pulmonary embolism has been reported. Therefore, prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were determined in venous plasma of 21 patients with acute pulmonary embolism. Venous plasma levels were followed up for one week after admission. Arterial and mixed-venous PG levels were additionally determined in 6 patients with acute pulmonary embolism prior to pulmonary angiography. Venous levels were substantially elevated (PGE2 16-1300, PGF2 alpha 48-592, TXB2 1-247, 6-ketoPGF1 alpha 1-248 pg/ml), differing significantly from normal controls (p less than 0.001). PG's remained elevated throughout the 7-day postadmission study period. No significant arterial-venous PG differences were detected, though 6-keto-PGF1 alpha and TXB2 levels were somewhat higher in arterial blood. There was no correlation between clinical data (blood pressure, mean pulmonary artery pressure, etc.) and PG levels. These data suggest that elevated prostaglandin levels are probably not, or only in part, responsible for the cardiopulmonary changes that occur in patients with acute pulmonary embolism.

Topics: 6-Ketoprostaglandin F1 alpha; Dinoprost; Dinoprostone; Humans; Prostaglandins; Prostaglandins E; Prostaglandins F; Pulmonary Embolism; Reference Values; Thromboxane B2; Time Factors

The contributions of thromboxane A2 (TXA2) and prostacyclin (PGI2) to the effects of acute pulmonary embolism were evaluated in 18 open-chest rabbits. All rabbits received autologous whole-blood-clot embolus (.4 cc) by way of a catheter in the right ventricle. Pulmonary artery (PA) and left atrial (LA) pressures, and aortic flow (AOQ) were recorded. The stable metabolites of TXA2 (TXB2) and PGI2 (6-Keto PGF1) were assayed by radioimmunoassay at pre- and post-embolization periods (+5, +10, +20, +30, and +40 minutes). Significant elevations of pulmonary vascular resistance (PVR) (normalized), PA pressure, and reduction of AOQ were noted comparing pre-embolus to +5 minute time intervals. A negative correlation was reached between PGI2 and AOQ at +40 minutes (p less than .05). Five of the 13 rabbits died prematurely. At +5 minutes these 5 rabbits had higher PVR (p less than .001) and lower AOQ (p less than .01) than their living counterparts. At +10 minutes AOQ was still significantly lower (p less than .005) and TXB2 was higher (p less than .05) in the premature death group. We conclude that TXB2 is significantly but transiently elevated early following acute pulmonary embolism and may contribute to mortality. In contrast PGI2 does not appear to play an immediate role in the hemodynamic events following embolization but does rise to significant levels later in the course possibly in an attempt to compensate for reduced flow.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Aorta; Blood Pressure; Epoprostenol; Kinetics; Male; Models, Biological; Prostaglandins; Pulmonary Artery; Pulmonary Embolism; Rabbits; Regional Blood Flow; Thromboxane A2; Thromboxane B2; Thromboxanes; Vascular Resistance

Prostacyclin (PG I2) generated by vascular endothelium is a strong antiaggregating substance. As platelet aggregation and release of humoral factor(s) have been reported to be crucial in the pathogenesis of acute lung injury following pulmonary microembolization, prostacyclin could have a protective effect against microembolic lung vascular injury. Following unilateral microembolization, the filtration coefficient in the nonembolized lung increased significantly to 0.14 +/- 0.02 from the base line value of 0.07 +/- 0.01 ml/min/mmHg/100g. Prostacyclin as measured as 6-keto PG F1 alpha in arterial blood increased significantly to 4.15 +/- 1.76 at 30 min from the base line value of 1.90 +/- 0.45 ng/ml and increased further to 5.67 +/- 1.49 ng/ml at 60 min following microembolization. Exogenously administered PG I2 methylester (20 ng/kg/min) prevented completely the increase in the filtration coefficient without any effects on hemodynamics, although the effects of PG I2 methylester did not depend on its action on platelet aggregation. Based on these results, we conclude that prostacyclin could play an important role in preserving cell integrity of the lung and prevention of increased lung vascular permeability following pulmonary microembolization.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Capillary Permeability; Dogs; Epoprostenol; Female; Hemodynamics; Kinetics; Lung; Male; Platelet Count; Prostaglandins; Pulmonary Embolism

Prostacyclin (PG I2) generated by vascular endothelium is a strong antiaggregating substance. As platelet aggregation and release of humoral factor(s) have been reported to be crucial in the pathogenesis of acute lung injury following pulmonary microembolization, PG I2 could have a protective effect against microembolic lung vascular injury. Following unilateral microembolization, we have observed a large increase in the filtration coefficient in the nonembolized lung with a significant increase in 6-keto PG F1 alpha, the stable metabolite of PG I2, in arterial blood. The pretreatment with indomethacin (10 mg/kg) prevented the increase in 6-keto PG F1 alpha and potentiated the lung injury after microembolization. Exogenously administered PG I2 (20 ng/kg/min) prevented completely the increase in the filtration coefficient without any effects on hemodynamics, although these effects of indomethacin and PG I2 did not relate to their effects on platelet aggregation. Based on these results, we could conclude that prostacyclin could play an important role in preserving cell integrity of the lung and in prevention of increased lung vascular permeability following pulmonary microembolization.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Capillary Permeability; Dogs; Epoprostenol; Female; Hemodynamics; Indomethacin; Male; Platelet Aggregation; Platelet Count; Pulmonary Circulation; Pulmonary Edema; Pulmonary Embolism

Embolisation of blood clots produced an increased pulmonary artery pressure in vitro and systemic hypotension in vivo. In control anaesthetized animals, systemic blood pressure fell by 44.9 +/- 28.0 mm Hg following embolisation and 40% of the animals died within 5 minutes of embolisation. Plasma concentrations of thromboxane B2 (TXB222222 2) and 6-keto-prostaglandin F 1 alpha (6-keto-PGF 1 alpha) were increased by 0.54 +/- 0.13 ng/ml and 0.41 +/- 0.25 ng/ml, respectively. Pretreatment of animals with aspirin (ASA), 5 mg/kg or 250 mg/kg, reduced the hypotensive response and the TXB 2 and 6-keto-PGF 1 alpha release. Embolisation of isolated lungs perfused with blood-free medium induced an increase in pulmonary artery pressure of 32.7 +/- 21.0 mm Hg and significantly increased the content of TXB 2 and 6-keto-PGF 1 alpha in the perfusate. Pretreatment of lungs with indomethacin, 10 micrograms/ml, reduced the mean pulmonary pressure response to embolisation to 10.6 +/- 4.9 mm Hg and blocked the appearance of TXB 2 in the perfusate. Embolisation with an agarose clot induced only a 2.58 +/- 0.8 mm Hg increase in pressure and no detectable TXB 2 release. These results indicate that embolisation of lungs with a blood clot induces the release of TXB 2 and 6-keto-PGF 1 alpha. The release of these mediators, the hemodynamic responses and mortality were blocked by ASA pretreatment.

Topics: 6-Ketoprostaglandin F1 alpha; Anesthesia, General; Animals; Aspirin; Hypotension; Indomethacin; Lung; Male; Perfusion; Pressure; Pulmonary Artery; Pulmonary Embolism; Rabbits; Thromboxane B2; Thromboxanes

Pulmonary emboli may impair myocardial performance, causing declines in cardiac index (CI) and right and left ventricular stroke work (LVSW) because of mechanical events. We postulate that embolism also leads to the generation of a humoral factor(s) that may reduce cardiac contractility. Eleven mongrel dogs were infused with 0.5 gm/kg clot. Decreases in CI and LVSW were observed 1 hour after embolization. The stable metabolites of prostacyclin and thromboxane (Tx) A2--6-keto-PGF1 alpha and TxB2, respectively--increased within 30 minutes (P less than 0.005, P les than 0.001) and then decreased. These changes did not correlate with the declines in CI or LVSW. Plasma from embolized animals used to bathe an isolated rat papillary muscle reduced developed tension (Tpd) (P less than 0.001) and decreased calcium ATPase (Ca++-ATPase) activity of a myofibril preparation (P less than 0.001) obtained from rat cardiac muscle. The correlation between the reduction of TPd and myofibril Ca++-ATPase activity was 0.72 (P less than 0.001). The decline in Ca++-ATPase was also related to the decreases in CI (r = 0.59, P less than 0.001) and LVSW (r = 0.57, P less than 0.001). Five animals pretreated with indomethacin prior to embolization had no decrease in LVSW as compared with controls (P less than 0.001). Postembolism plasma did not depress papillary muscle Tpd and did not lower Ca++-ATPase activity of myofibrils. Anesthesia itself did not alter cardiopulmonary function. These results suggest that pulmonary emboli cause the release of a negative inotropic agent(s) into plasma that affects energy availability in the heart and reduces contractility. The production of this agent(s) is inhibited by indomethacin pretreatment.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Calcium-Transporting ATPases; Cardiac Output; Dogs; Epoprostenol; Indomethacin; Myocardial Contraction; Papillary Muscles; Pulmonary Embolism; Rats; Stroke Volume; Thromboxanes

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Dogs; Histamine; Hypoxia; Pulmonary Embolism; Serotonin; Thromboxane B2; Thromboxanes

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Cardiac Output; Dogs; Fibrin Fibrinogen Degradation Products; Positive-Pressure Respiration; Prostaglandins E; Prostaglandins F; Pulmonary Artery; Pulmonary Embolism; Thromboxane B2