A modified method for extraction and purification of prostaglandins with resin XAD-2

Single dose of acetylsalicylic acid prevents thromboxane release after tourniquet ischemia

BACKGROUND

Ischemia, such as that caused by a tourniquet, stimulates thromboxane (Tx) A(2) synthesis. TxA(2) might sensitize the operated limb to various complications, such as compartment syndrome and thromboembolic events.

METHODS

We studied the effect of pretreatment with a single dose of acetylsalicylic acid (ASA) (25, 100, and 500 mg) given 3 hours before surgery on the formation of TxB(2), a stable metabolite of TxA(2), after tourniquet deflation in 32 knee or ankle surgery patients.

RESULTS

Tourniquet time varied between 60 +/- 8 to 71 +/- 7 (SE) minutes. In control patients without ASA pretreatment, the platelet-produced femoral vein serum TxB(2) concentration over 30 minutes in vitro coagulation increased remarkably (from 40.0 +/- 20 ng/mL to 73.5 +/- 39 ng/mL) immediately after tourniquet deflation. Plasma concentrations increased similarly, approximately threefold. Pretreatment with 100 or 500 mg ASA prevented the increase in TxB(2) concentrations. Radial artery concentrations of TxB(2) were similar to venous concentrations in the different treatment groups.

CONCLUSION

Pretreatment with a single 100-mg dose of ASA prevents the release of TxB(2) after tourniquet deflation.

Nifedipine reduces thromboxane A2 production by platelets without changing aggregation in hypertensive pregnancy

Platelet aggregation and thromboxane A2 generation were studied in hypertensive pregnant women using normotensive non-pregnant and pregnant controls. In hypertensive pregnancy, adrenaline- and adenosine diphosphate-induced platelet aggregation was at the non-pregnant level and lower than in normotensive pregnancy. Collagen-induced aggregation was at a lower level in hypertensive pregnancy than in both control groups. Thromboxane generation during spontaneous clotting and in platelet-rich plasma did not differ between the three groups. However, thromboxane generation was low during aggregation induced by small collagen concentrations in hypertensive pregnancy, but at higher collagen concentrations the difference between the groups disappeared. During nifedipine treatment (10 mg t.i.d.), aggregation and thromboxane production in platelet-rich plasma induced by the three stimuli remained unaltered in hypertensive pregnancy, while thromboxane synthesis during spontaneous clotting was reduced. In nifedipine-treated non-pregnant controls, only EC80 for adrenaline-induced aggregation decreased. In vitro, pharmacological concentrations of nifedipine inhibited platelet aggregation and thromboxane production. In conclusion, nifedipine reduces thromboxane generation in spontaneous clotting, without inhibiting platelet aggregation and thromboxane production in platelet-rich plasma in hypertensive pregnancy. Reduced aggregability of platelet ex vivo may reflect their continuous activation and desensitization in vivo in hypertensive pregnancy.

Interrelationships between salt and fish oil in stroke-prone spontaneously hypertensive rat

The cardiovascular effects of a partially purified extract of fish oil, enriched in the n-3 series fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were studied in stroke-prone spontaneously hypertensive rats (SHR-SP) fed with high- and low-sodium diets during 5 weeks. Addition of salt to the low-salt control diet at a level commonly found in human food items (6% NaCl of the dry weight of the diet) produced a remarkable rise in blood pressure, an increase in left ventricular weight-to-body weight ratio (LVH-index) and an increase in kidney weight-to-body weight ratio (RH-index). Fish oil (20% of the dry weight of the diet) did not significantly influence the blood pressure or LVH-index or RH-index during the low-salt control diet. However, fish oil completely prevented the remarkable rise in blood pressure and clearly antagonized the rise of both LVH- and RH-indices, induced by the high-salt diet. The fish oil supplementation increased the levels of the polyunsaturated fatty acids of the n-3 series and decreased those of the n-6 series in plasma and kidney, irrespective of the salt content of the diet. Fish oil lowered serum thromboxane B2 concentration by approximately 75%. During the high-salt diet, fish oil markedly decreased water intake and urine volume, and increased urinary sodium concentration by about 60%. Our findings show that, in addition to an antihypertensive effect, fish oil also decreases LVH and RH. These effects appear to be due to an improved ability to excrete sodium and could be explained by the observed changes in the fatty acid composition and metabolism.

Noradrenaline and dopamine infusions modulate arachidonic acid cyclooxygenase and 5-lipoxygenase pathways ex vivo in man

We have previously demonstrated that adrenaline infusion increases the thromboxane/leukotriene (TX/LT) ratio in whole blood in healthy volunteers. The aim of the present study was to see whether other catecholamines--noradrenaline and dopamine--are also capable of modulating arachidonic acid (AA) metabolism in man. Low doses of noradrenaline (0.025 microgram/kg/min) and dopamine (3.0 micrograms/kg/min), which did not change hemodynamics, were infused for 60 min into healthy male volunteers. Both dopamine and noradrenaline decreased TX synthesis stimulated by spontaneous clotting, but no remarkable effect was seen when calcium ionophore A23187 was used as a stimulus. Dopamine but not noradrenaline increased prostaglandin E2 (PGE2) synthesis in A23187-stimulated whole blood. They both marginally decreased LTB4 formation in A23187-stimulated whole blood. The findings indicate that not only adrenaline but also noradrenaline and dopamine modulate AA metabolism in man.

Cardiovascular effects of Atenolol, scopolamine and their combination on healthy men in Finnish sauna baths

Indicators of cardiovascular strain were studied in 12 healthy young men under the influence of drugs affecting the autonomic nervous system during the course of taking a sauna bath. There were four bath sessions: one without a drug (control) and three with drug pretreatment (Atenolol 50 mg or Scopolamine 0.3 mg or their combination taken orally 2 h before the bath). The time spent in the hot room depended on the subjective rating of heat stress. Its mean duration at a temperature of 88 degrees C (dry bulb) was 22 (range 14-33) min and did not differ significantly among the sessions. In the Atenolol experiment the mean resting heart rate before the bath was significantly lower (P < 0.001, ANOVA of repeated measures) than in the other experiments. The increase in heart rate per minute of heat exposure was significantly lower (P < 0.001) in the Atenolol experiment and higher (P = 0.017) in the Scopolamine experiment than in the other experiments. The systolic blood pressure increased more slowly (P = 0.004) and the diastolic pressure decreased less (P = 0.02) in the Atenolol experiment than in the other experiments. Heart rate and blood pressure returned to their initial levels during the 30-min recovery after the heat exposure. The plasma noradrenaline concentrations increased approximately twofold during all of the bath sessions, whereas the plasma adrenaline and serum thromboxane B2 concentrations showed no consistent alterations. A small oral dose of Scopolamine alone or in combination with Atenolol produced no marked cardiovascular strain in healthy men during a sauna bath.

Comparison of in vitro effects of flunixin and tolfenamic acid on human leukocyte and platelet functions

A study was made to compare the effects of two nonsteroidal antiinflammatory drugs (NSAIDs), flunixin and tolfenamic acid, on the leukotriene B4 (LTB4) production and migration of human polymorphonuclear leukocytes (PMNs) as well as on platelet aggregation and thromboxane B2 (TxB2) production during blood clotting. Tolfenamic acid inhibited LTB4 production in PMNs as well as FMLP- and LTB4-induced PMN migration (IC50 values 23 +/- 3, 39 +/- 11, and 68 +/- 13 microM, respectively), whereas flunixin inhibited these cell functions only with the highest concentration tested (100 microM). On the other hand, flunixin was clearly a more potent inhibitor of TxB2 production and adrenaline-induced platelet aggregation than tolfenamic acid, the IC50 values in TxB2 production being 0.28 +/- 0.02 microM and 2.6 +/- 0.3 microM for flunixin and tolfenamic acid, respectively. We suggest that inhibition of PMN functions may be an additional mechanism in the antiinflammatory action of tolfenamic acid. At least in human PMNs and platelets, flunixin seems to be only an inhibitor of cyclooxygenase.

Anti-inflammatory activities of Emblica officinalis Gaertn leaf extracts

Emblica officinalis Gaertn, a tree growing in subtropical and tropical parts of China, India, Indonesia and the Malay Peninsula, has been used for anti-inflammatory and antipyretic treatments of rural populations in these areas. In the present study, we examined the effects of Emblica officinalis extracts on carrageenan- and dextran-induced rat hind paw oedema. Anti-inflammatory activity was found in the water fraction of methanol extract of the plant leaves. The effects of the same fraction were tested on the synthesis of mediators of inflammation such as leukotriene B4 (LTB4), platelet-activating factor (PAF) and thromboxane B2 (TXB2), and on LTB4- and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced migration of human polymorphonuclear leucocytes (PMNs) in-vitro. The water fraction of the methanol extract inhibited migration of human PMNs in relatively low concentrations. It did not inhibit LTB4 or PAF synthesis in human PMNs or TXB2 synthesis in human platelets during clotting, suggesting that the mechanism of the anti-inflammatory action found in the rat paw model does not involve inhibition of the synthesis of the measured lipid mediators.

Effects of phenols on eicosanoid synthesis in A23187-stimulated human whole blood

We have previously demonstrated that catecholamines have opposite effects on leukotriene (LT) and prostanoid synthesis. The aim of the present study was to test the effects of phenols (catechol, hydroquinone, phenol and resorcinol) on LTB4, LTE4 and thromboxane (TX)B2 synthesis in A23187-stimulated human whole blood. All tested compounds inhibited LTB4 and LTE4 synthesis. The IC50 values for catechol were 3 microM, 6 microM; for hydroquinone 4 microM, 3 microM; for phenol 285 microM, 226 microM and for resorcinol 180 microM, 902 microM. The compounds did not stimulate TXB2 synthesis but only inhibited it. The IC50 value for catechol was 3 microM, for hydroquinone 7 microM, for phenol 18 microM and for resorcinol 25 microM. Catechol and hydroquinone had hardly any effect on the LT/TX ratio. Phenol and resorcinol even increased the LT/TX ratio. The positions of hydroxyl groups of phenolic compounds are thus important for their actions on the LT/TX ratio.

Nifedipine increases urinary excretion of prostacyclin metabolite in hypertensive pregnancy

Renal prostanoid excretion was investigated in nine hypertensive pregnant patients before and during treatment with nifedipine 10 mg orally t.i.d. Urinary excretion of prostacyclin (measured as 6-ketoprostaglandin F1 alpha, 6-keto-PGF1 alpha) increased by 77% during nifedipine treatment (P less than 0.05). No changes were found in prostaglandin E2 (PGE2) and thromboxane A2 (as thromboxane B2, TXB2) excretions. A significant reduction in blood pressure did not correlate with an increase in 6-keto-PGF1 alpha excretion. Plasma prekallikrein and urinary kallikrein and catecholamine excretions remained unaltered. In six normotensive non-pregnant women, increase in 6-keto-PGF1 alpha excretion during nifedipine treatment was not significant. No changes in PGE2 and TXB2 excretions were found, whereas plasma prekallikrein was reduced (P less than 0.05) and urinary excretion of kallikrein (P less than 0.05) and noradrenaline (P = 0.06) increased under nifedipine. The results suggest that nifedipine enhances the renal 6-keto-PGF1 alpha excretion in hypertensive pregnancy.

Catecholamines inhibit leukotriene formation and decrease leukotriene/prostaglandin ratio

Adrenaline, noradrenaline, isoprenaline, and to a lesser extent dopamine inhibit the release of leukotriene (LT) B2 from calcium ionophore-stimulated human polymorphonuclear leukocytes, while the release of prostaglandin (PG) E2 is proportionally elevated. The inactivity of salbutamol, a noncatechol adrenergic beta 2-receptor agonist, and the inability of propranolol to antagonize the effects of adrenaline, suggest the mediation through beta-receptor independent mechanisms. Neither are alpha-1-receptors involved, as prazosin, a specific antagonist, fails to inhibit the reaction. As the principles for biochemical regulation of LT- and PG-production are met by catecholamines in several tissues, the mechanism is considered to be of general physiological importance. Catecholamines may function as coenzymes/antioxidants which, by altering the redox state of the enzyme iron or heme, decrease the LT/PG ratio thus protecting the organism against tissue anaphylaxis and other LT-related pathophysiology.

Cholesterol lowering effect of metformin in combined hyperlipidemia: placebo controlled double blind trial

Metformin, an antidiabetic biguanide derivative, prevents experimental atherosclerosis and induces structural changes in lipoproteins in experimental animals. In the present study we investigated the effect of metformin on serum lipoproteins and platelet function in 24 non-diabetic patients with type II B hyperlipidemia. The patients were randomly given metformin in two dosage levels (1.0 g/day and 2.0 g/day) and placebo for periods of nine weeks in a crossover trial. Metformin caused a dose dependent fall in the concentrations of total serum cholesterol and of LDL-cholesterol. The average concentration of total cholesterol was 8.54 +/- 0.22 (SE) mmol/l, 8.12 +/- 0.19 mmol/l and 7.79 +/- 0.15 mmol/l during placebo, metformin 1.0 g/day and 2.0 g/day treatments, respectively. Both metformin values differed significantly (P less than 0.05) from the placebo value. Thus there was an average fall of 8.1% in total cholesterol after the higher metformin dose. LDL-cholesterol was 5.25 +/- 0.23 mmol/l after placebo, falling by 3.1% and 9.6% after metformin doses of 1.0 g/day and 2.0 g/day, respectively. The concentrations of HDL-cholesterol and total serum triglycerides showed no significant changes. Body weight, blood glucose, plasma insulin, blood lactate, platelet function and urinary excretion of prostanoids remained unchanged during the study. The reduction of total- and LDL-cholesterol levels may be a welcome additional consequence of metformin during treatment of diabetic patients with hypercholesterolemia.

Effects of non-steroidal anti-inflammatory drugs and prednisolone on synovial fluid white cells, prostaglandin E2, leukotriene B4 and cyclic AMP in patients with rheumatoid arthritis

Altogether 53 patients (31 women, 22 men) with definite rheumatoid arthritis were randomly divided into groups of 5-6 patients and treated for one day only with one of the following non-steroidal anti-inflammatory drugs (NSAIDs): acetylsalicylic acid, carprofen, diclofenac, indomethacin, naproxen, proquazone, timegadine, tolfenamic acid or paracetamol, and with prednisolone, in recommended doses. Synovial fluid samples were collected before and after the treatment. White cell count and its differentiation as well as the concentrations of protein, cyclic adenosine-3',5'-monophosphate (cAMP), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were measured from the synovial fluid. Synovial fluid leukocyte counts correlated with PGE2 concentrations, but showed no correlation with LTB4 levels before treatment. Significant changes were seen in the form of lowered PGE2 values following treatment with the clinically and experimentally most potent NSAIDs, and as depressed LTB4 levels following prednisolone treatment. The other markers of inflammation are obviously more resistant, changing only slowly during prolonged treatment, and may thus be, at least in part, secondary to the changes in prostanoids.

Eicosanoid production in rheumatoid synovitis

Leukotriene B4 (LTB4) synthesis in rheumatoid synovitis was studied using peripheral and synovial fluid polymorphonuclear leukocytes (PMNs) and rheumatic synovial lining cells. No differences were found in LTB4 synthesis between peripheral PMNs from healthy volunteers and rheumatoid arthritis patients. When peripheral and synovial PMNs from the same RA patient were compared, arachidonic acid-induced LTB4 synthesis in synovial fluid PMNs was increased 1.7-7.2 fold, whereas the response to Ca ionophore A23187 stimulation was similar. This suggests 5-lipoxygenase stimulating factor(s) in inflamed joints. Rheumatic synovial lining cells in a primary cell culture produced small amounts of LTB4, the concentrations being less than 0.1 per cent of those of prostaglandin E2 (PGE2). PGE2 synthesis in synovial cells was increased when arachidonic acid or interleukin-1 was added to the culture, whereas LTB4 production remained unaltered. The present results suggest that in inflamed joints LTB4 originates mainly from PMNs whereas synovial lining cells are the source for PGE2.

Orally administered tolfenamic acid inhibits leukotriene synthesis in isolated human peripheral polymorphonuclear leukocytes

Special interest has been focused on the development of dual inhibitors of the cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism. In contrast to other classic NSAIDs, some fenamates in clinically achievable concentrations have been shown to inhibit synthesis of 5-lipoxygenase products in vitro. In the present work, we studied the effect of orally administered tolfenamic acid (600 mg) on Ca ionophore A 23187 -induced leukotriene synthesis in isolated human polymorphonuclear leukocytes. Leukotriene production was reduced in all 14 subjects studied, the mean inhibition of LTB4 synthesis being 16 +/- 3% and that of LTC4 33 +/ 7%. The inhibition correlated positively with serum acid concentrations. We suggest that inhibition of leukotriene synthesis is an additional mechanism of the anti-inflammatory, antimigraine and antidysmenorrhoeic effects of tolfenamic acid, and a possible explanation for its rare gastric and bronchoconstrictive side-effects.

Plasma thromboxane B2 levels and thromboxane B2 production by platelets are increased in patients during spinal and epidural anesthesia

Concentrations of thromboxane (Tx) B2 in plasma and its production by platelets were measured in 20 spinal and 10 epidural anesthesia patients scheduled for small operations in the lower extremities. The main metabolite of prostacyclin, 6-keto-PGF1 alpha and prostaglandin (PG) E2 in plasma were also determined. Plasma TxB2 and TxB2 production by platelets increased during both spinal and epidural anesthesia. Plasma TxB2 levels also remained elevated 1 h after anesthesia. The plasma concentrations of 6-keto-PGF1 alpha and PGE2 did not change during spinal or epidural anesthesia. In in vitro studies, only low concentrations of lidocaine (0.5-1.0 micrograms/ml) and bupivacaine (0.5-3.0 micrograms/ml) increased platelet TxB2 production. In platelet rich plasma, neither lidocaine nor bupivacaine in concentrations of 0.5-3.0 micrograms/ml caused constant changes in ADP-induced platelet aggregation, but they inhibited it in toxic concentrations (12 micrograms/ml). The results suggest that the increased TxB2 plasma levels and platelet TxB2 production during regional anesthesia are not caused by local anesthetics itself but by other factors, e.g. tissue trauma. In clinically found concentrations, local anesthetics do not cause any constant changes in platelet aggregation.

Evening primrose oil and olive oil in treatment of rheumatoid arthritis

The effects of 10 ml of evening primrose oil or olive oil, administered twice daily for 12 weeks, on clinical and laboratory signs and on plasma prostaglandins were studied in 18 patients with rheumatoid arthritis. The plasma concentration of PGE2 decreased and that of TxB2 increased in both treatment groups, but no significant improvement could be seen in either group.

Prostanoids and catecholamines after oral administration of natural progesterone

Natural exogenous progesterone has been shown to affect the functioning of the central nervous system in man, inducing dizziness and sedation by unknown mechanisms. Seven postclimacteric women known to suffer from dizziness during natural progesterone therapy were treated with a single oral dose of 200 mg of natural progesterone on 2 occasions, with and without preceding administration of indomethacin. Cardiovascular responses, vasoactive prostanoids and catecholamines in the blood, and excretion of prostanoids in the urine were measured. Serum progesterone concentrations increased in each subject, and all the women experienced dizziness or tiredness after progesterone intake. Blood pressure and heart rate did not change. Urine excretion of immunoreactive prostaglandin E2 and 6-keto-prostaglandin1 alpha decreased significantly in the experiment without pretreatment with indomethacin, whereas indomethacin pretreatment reduced the basal excretion of prostanoids and abolished the progesterone-induced decrease in their excretion. The plasma concentrations of prostanoids and catecholamines did not change. The results confirm that natural progesterone can cause dizziness and tiredness in man. The appearance of these symptoms is not related to peripheral vasodilation or to changes in plasma prostanoid or catecholamine levels. Neither are the symptoms related to the alteration in the urinary excretion of prostanoids, since the women still suffered from tiredness and dizziness after pretreatment with indomethacin.

Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath

Eight healthy young men were studied during three periods of heat exposure in a Finnish sauna bath: at 80 degrees C dry bulb (80 D) and 100 degrees C dry bulb (100 D) temperatures until subjective discomfort, and in 80 degrees C dry heat, becoming humid (80 DH) until subjective exhaustion. Oral temperature increased 1.1 degrees C at 80 D, 1.9 degrees C at 100 D and 3.2 degrees C at 80 DH. Heart rate increased about 60% at 80 D, 90% at 100 D and 130% at 80 DH. Plasma noradrenaline increased about 100% at 80 D, 160% at 100 D and 310% at 80 DH. Adrenaline did not change. Plasma prolactin increased 2-fold at 80 D, 7-fold at 100 D and 10-fold at 80 DH. Blood concentrations of the beta-endorphin immunoreactivity at 100 D, adrenocorticotropic hormone (ACTH) at 100 D and 80 DH, growth hormone at 100 D and testosterone at 80 DH also increased, but cortisol at 80 D and 100 D decreased. The plasma prostaglandin E2 and serum thromboxane B2 levels did not change. Patterns related to heat exposure were observed for heart rate, plasma noradrenaline, ACTH and prolactin in the three study periods.

Effects of diclofenac, indomethacin, tolfenamic acid and hydrocortisone on prostanoid production in healthy and rheumatic synovial cells

Prostanoids, found in enhanced concentrations in rheumatic synovial fluid, are involved in the joint destruction seen in rheumatoid arthritis. Adherent cells isolated from rheumatic synovia produce higher amounts of prostanoids in a primary cell culture than cells originating from non-inflamed synovia. In the present study, it was found that exogenous arachidonic acid diminished the differences in prostanoid production between healthy and rheumatic synovial cells. Non-steroidal anti-inflammatory analgesics in clinically relevant concentrations had similar inhibitory effects on arachidonic acid-stimulated prostanoid synthesis in both healthy and rheumatic cells. In the presence of exogenous arachidonic acid, hydrocortisone (0.3-5.0 microM) did not affect prostanoid production in healthy cells. In rheumatic synovial cells hydrocortisone reduced PGE2 and PGF2 alpha synthesis to about half of the control value and the effect was not reversed by adding excess exogenous arachidonic acid. Altered regulation of phospholipase A2 activity in rheumatic synovia could explain the observed differences between healthy and rheumatic synovial cells.

Renal excretion of prostanoids and cyclic AMP in chronic partial ureteral obstruction of the rabbit

The renal excretion of prostaglandins E2 and 6-keto-F1 alpha, thromboxane B2 and cyclic adenosine 3', 5'-monophosphate was measured in a solitary kidney model of chronic ureteral obstruction in rabbits. The presence of obstruction was confirmed by intravenous pyelography. Growth rate of the animals and furosemide-stimulated diethylenetriaminepentaacetic acid renography were used to grade the obstruction. As correlated to urinary creatinine concentration the excretion of 6-keto-PGF1 alpha dominated in nephrectomized, unobstructed control animals. With the degree of ureteral obstruction becoming more severe, the output of PGE2 increased, while that of 6-keto-PGF1 alpha and TxB2 decreased. As a result the ratios PGE2/6-keto-PGF1 alpha and PGE2/TxB2 were three times as high in severely obstructed rabbits as in control animals. The renal output of cyclic AMP was unaffected by chronic obstruction. We conclude that the renal metabolism of prostanoids is affected in a unique way in chronic partial obstruction of the ureter.

Effect of indomethacin on peripheral tissue perfusion after coronary artery bypass surgery

The effect of indomethacin on peripheral tissue perfusion in the early phase after coronary artery bypass grafting (CABG) was investigated in ten patients randomly allocated to receive indomethacin 25 mg i.v. or placebo 'double-blind'. The patients were coupled to a respirator with FiO2 30 v/v %. Central haemodynamics, intrapulmonary shunt and blood gases showed no significant change in either group during the 2-hour study period. The thromboxane A2 metabolite P-TXB2 decreased significantly (p less than 0.05) in the indomethacin group, but the prostacyclin metabolite P-6-K PGF1 alpha showed no significant change in either group. The PtcO2 index (transcutaneous oxygen tension/arterial PO2), measured in the upper extremity, rose (p less than 0.05) after indomethacin infusion, but was almost unchanged in the controls. The mean subcutaneous tissue oxygen tension and the laser-Doppler skin red-cell flux underwent no significant change. The data thus suggested that indomethacin administered intravenously post-CABG may exert beneficial effects on peripheral tissue perfusion and oxygenation, possibly mediated by improvements in prostacyclin-thromboxane balance and microcirculation.

Effects of antirheumatic drugs on leukotriene B4 and prostanoid synthesis in human polymorphonuclear leukocytes in vitro

The effects of D-penicillamine, sodium aurothiomalate, indomethacin, timegadine and tolfenamic acid on the lipoxygenase and cyclo-oxygenase pathways of arachidonic acid metabolism were studied in human polymorphonuclear leukocytes (PMNs) in vitro. In short-term incubations, D-penicillamine and aurothiomalate did not affect leukotriene B4 (LTB4), prostaglandin E2 (PGE2) or thromboxane B2 (TXB2) production. Each of the three non-steroidal anti-inflammatory drugs (NSAIDs) used were potent inhibitors of prostanoid synthesis. In higher concentrations they also reduced LTB4 production; timegadine and tolfenamic acid were effective in concentrations comparable to those measured in plasma during drug therapy, whereas indomethacin was needed in ten times higher concentrations. The different effects of NSAIDs on 5-lipoxygenase activity may be of importance in their therapeutic actions as well as in the appearance of some side-effects, e.g. gastric irritation and "aspirin-induced" asthma.

Prostanoids and cyclic nucleotides in malignant and benign ovarian tumors

The concentrations of prostaglandin E2 (PGE2), 6-keto-PGF1 alpha, thromboxane B2(TxB2), cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in ovarian tumor tissue were measured in 38 post-menopausal women with malignant or benign ovarian tumor and in six women without ovarian neoplasm. PGE2 and TxB2 contents in ovarian cancer tissue were significantly (P less than 0.05) higher than in normal ovarian tissue. The prostanoids were also increased in the cyst fluid of epithelial malignant tumors compared to cyst fluids of benign ovarian tumors. Cyclic AMP concentrations in cancer tissue were lower than in non-malignant ovarian tissue, while the levels of cGMP were similar in all groups studied.

The validity of immunological studies in human immunodeficiency virus infection: a three-year follow-up of 235 homo- or bisexual persons

During a three-year follow-up study of 235 risk-group people living in Finland, we found a slow increase in the proportion of HIV seropositives (from 9.8% to 14.0%) and a slow but continuous advance in symptoms typical of HIV infection among them. The first immunological changes after HIV seroconversion were an increase in Ts-cells and a decline in antigen-induced T-cell functions (proliferation, IL-2 production). A further decline in antigen-induced responses was seen before early clinical symptoms and signs of HIV infection developed. During later phases of HIV infection the decrease of Th-cells and the elevation of serum Beta-2 microglobulin correlated most strongly with the progression of HIV infection. The mitogen-induced lymphocyte functions of the HIV-infected correlated to Th-cell levels, while the antigen-induced proliferation and IL-2 production showed correlation neither to Th-cells nor to Ts-cells. The poor antigen-induced T-cell responses might be caused by abnormally functioning monocytes, known to be infected by HIV. Our results suggest that in HIV infection there is a continuous but slow disease progression, although individual variation may be great. The immunological parameter best predicting the prognosis of an infected person in the early phases of infection was the antigen-induced lymphocyte functions, and later the amount of Th-cells.

Effects of halothane and enflurane on prostanoid concentrations in operation patients

Prostanoid formation may be stimulated by different events associated with anaesthesia and operation, such as positive pressure ventilation and tissue trauma. We investigated the effects of halothane and enflurane on plasma and serum prostanoid concentrations in 19 patients scheduled for minor operations. In 9 abdominal surgery patients, thromboxane B2 concentrations were followed up to the fifth postoperative day. Prostanoid determinations were carried out with RIA. In general, the changes in prostanoid concentrations in patients anaesthetised with halothane or enflurane were similar. During spontaneous breathing there was a decrease in plasma PGE2 and TxB2 concentrations. During intermittent positive pressure ventilation and operation, PGE2 and TxB2 concentrations rose but 6-keto-PGF1 alpha did not. After operation, TxB2 concentrations remained elevated but the other prostanoids returned to preoperative values. TxB2 concentrations decreased to the preoperative level on the first postoperative day. The elevated TxB2 concentrations during and after surgery can be regarded, in some patients, as a potential risk factor for cardiovascular and thromboembolic complications.

Effects of indomethacin on hormonal and blood pressure responses to captopril in spontaneously hypertensive rats

The possible role of vasodilatory prostanoids in the antihypertensive action of captopril was investigated in spontaneously hypertensive rats (SHR). Captopril (100 mg/kg/day for 5 days) decreased systolic blood pressure and increased water consumption, urine excretion and plasma renin activity (PRA). It also enhanced the urinary excretion of the prostacyclin metabolite 6-keto-PGF1 alpha, but did not change the excretion of PGE2. Indomethacin (3 mg/kg/day), given both alone and in combination with captopril, reduced markedly the urinary excretions of 6-keto-PGF1 alpha and PGE2 but did not alter PRA, compared with corresponding groups without indomethacin. The suppression of prostanoid synthesis caused by indomethacin did not affect the antihypertensive effect of captopril or the basal blood pressure in SHR. Neither did indomethacin influence drinking or urine excretion in SHR not receiving captopril, but it reduced the dipsogenic and diuretic effects of captopril. The results suggest that captopril augments the production of vasodilatory prostacyclin. Yet prostanoids have no significant role in the antihypertensive mechanism of captopril in SHR.

Neonatal respiratory distress caused by aspiration of a vaginal tablet containing prostaglandin

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D-penicillamine effects on prostanoid production in adherent rheumatic synovial cells in primary culture

The effect of D-penicillamine (DPA) on immunoreactive prostanoid concentrations was studied in a primary culture of adherent synovial cells from patients suffering from rheumatoid arthritis (RA). DPA in clinically achievable concentrations increased the levels of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) and reduced those of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) synthetized from endogenous substrate. The capacity for PGE2 and 6-keto-PGF1 alpha production in the presence of exogenous arachidonic acid was decreased by DPA. These effects may be connected with the antirheumatic and immunosuppressive action of DPA.

Production of prostanoids by rheumatic synovial cells in vitro: effects of anti-inflammatory drugs on arachidonic acid metabolism

To evaluate the role of prostanoids in rheumatoid arthritis the effects of anti-inflammatory drugs on prostanoid concentrations and their ratios were studied in a primary culture of adherent synovial cells from patients with rheumatoid arthritis. Cells from rheumatoid synovium have a great capacity for prostanoid production. PGE2 is the main prostanoid but synovial cells are also capable of producing 6-keto-PGF1 alpha and PGF2 alpha. There were also very low TxB2 concentrations in the culture medium after incubation. All nonsteroidal anti-inflammatory drugs used (diclofenac, indomethacin and tolfenamic acid) reduced markedly, in concentrations achieved therapeutically (greater than or equal to 0.13 mumol/l), the production of all the prostanoids from endogenous substrate. There were no differences in the efficacity of the drugs. Hydrocortisone was needed for higher concentrations to inhibit PGE2, 6-keto-PGF1 alpha and PGF2 alpha production. TxB2 formation remained almost unaltered. After the drug incubation there were also clear alterations in the ratios between these prostanoids, which may have therapeutic importance. It is suggested that this kind of synovial cell culture can be used for testing the effects and mechanisms of different anti-inflammatory drugs in standardized cell culture conditions.

Differences in prostanoid production between healthy and rheumatic synovia in vitro

To evaluate further the complex role of prostanoids in rheumatoid arthritis we compared the immunoreactive prostanoid production of healthy and rheumatic synovial cells in a primary cell culture. During the first days in culture the adherent cells from rheumatic synovia produced higher amounts of prostanoids, especially the proinflammatory and immunosuppressive prostaglandin E2 (PGE2), than cells originating from non-inflamed synovia. This difference disappeared within one week culture and was partly explained by altered substrate availability.

Effect of ovariectomy in humans on serum 6-keto-PGF1 alpha and TXB2 concentrations and platelet fatty acids

The effects of ovariectomy on serum 6-keto-PGF1 alpha and TXB2 concentrations and platelet fatty acids were investigated. One month after ovariectomy the levels of 6-keto-PGF1 alpha were unaltered, whereas those of TXB2 were significantly increased. Ovariectomy had no effect on the fatty acid composition of platelets. Thus, the present study suggests that the hormonal changes at the time of menopause may modify the formation of metabolites of arachidonic acid.

Adrenaline infusion evokes increased thromboxane B2 production by platelets in healthy men: the effect of beta-adrenoceptor blockade

The effects of direct adrenergic stimulation, achieved by 60-min adrenaline infusion (0.1-0.2 microgram kg-1 min-1), on thromboxane B2 (TxB2) production by platelets in whole blood ex vivo and on ADP-induced platelet aggregation were studied in seven healthy male volunteers. The effects of two beta-adrenergic blocking agents, pindolol and practolol, on the adrenaline-induced changes were furthermore analyzed. Adrenaline administration resulted in an about ten-fold elevation in plasma adrenaline, and an about three-fold increase in TxB2 production by platelets at 30 min of infusion. The increased TxB2 production persisted throughout the entire adrenaline infusion, and up to 30 min of postinfusion period (recovery). Pindolol blunted markedly the effects of adrenaline on platelet TxB2 production, whereas practolol seemed to have only a weak effect. The sensitivity of platelets to ADP-induced aggregation did not change during the 60 min of adrenaline infusion. However, at 60 min of recovery the platelets showed a significantly increased sensitivity to ADP. Correspondingly, pindolol treatment did not affect platelet sensitivity during the infusion period, but at 60 min of recovery it had caused a significantly decreased sensitivity of platelets to ADP-stimulation. Plasma-free fatty acids increased markedly during the adrenaline infusion. This increase was totally blocked by pindolol, but only partly by practolol. The present results demonstrate that adrenaline, at plasma levels seen for example, in complicated myocardial infarction, stimulates platelet TxB2 production and increases the sensitivity of platelets to ADP after the infusion. Pindolol, but not practolol, inhibits these adrenaline-induced changes in platelet behaviour.

Fatty acid composition and arachidonic acid metabolites in ascitic fluid of patients with ovarian cancer

Fatty acid composition and arachidonic acid metabolites in ascitic fluids of patients with ovarian cancer were compared to those in the peritoneal fluids of patients with benign gynecologic conditions. Substantial amounts of PGE2, PGF2 alpha, TXB2, and leukotriene B4 were detected in the fluids of the both patient groups. In the group of the cancer patients the concentrations of TXB2 were slightly smaller than those in the control group. In the percentage amounts of the eicosanoid precursor fatty acids there could not be detected differences between these two groups. However, in the peritoneal fluids of the cancer patients the percentage amount of palmitoleic acid (16:1) was significantly higher than that in the control group.

The effect of pindolol on exercise-induced increase in plasma vasoactive prostanoids and catecholamines in healthy men

The effect of intravenous pindolol (0.0256 mg/kg) on changes in plasma arachidonic acid (AA), some of its metabolites, and catecholamines induced by submaximal exercise was studied in six healthy male volunteers. Exercise resulted in markedly increased plasma concentrations of thromboxane B2 (TxB2) from 0.13 +/- 0.01 to 0.27 +/- 0.02 pmol/ml (mean +/- SEM; p less than 0.05) and AA from 4.1 +/- 0.6 to 8.0 +/- 0.9 mumol/l (p less than 0.005). No significant changes were seen in plasma concentrations of 6-keto-PGF1 alpha or PGE2 during exercise. A marked increase in plasma noradrenaline was seen already at 15 min of exercise, while the adrenaline concentration increased significantly at 30 min of exercise and a very marked increase in the adrenaline concentration was seen at exhaustion. A positive correlation (r = 0.54; p less than 0.05) was seen between plasma TxB2 and plasma adrenaline during exercise. The peak increase in both of these parameters was seen simultaneously at exhaustion. Pindolol treatment resulted in almost total inhibition of the increase in plasma TxB2 and AA during exercise. Pindolol treatment also resulted in a significantly higher adrenaline level at exhaustion. These data seem to indicate that an increased sympathetic tone may result in an increased release of arachidonic acid in the formation of vasoconstrictive thromboxane A2.

Comparison of the effects of different anti-inflammatory drugs on synovial fluid prostanoid concentrations in patients with rheumatoid arthritis

The effects of one-day treatment with nine nonsteroidal anti-inflammatory drugs and prednisolone on human synovial fluid concentrations of prostanoids were studied. The doses were calculated so as to be approximately equipotent according to clinical experience and the recommendations of the manufacturers. Most of the drugs used reduced clearly PGE2 and TxB2 levels in synovial fluid, but only a slight diminution in 6-keto-PGF1 alpha values was found. Carprofen, diclofenac, indomethacin, naproxen and tolfenamic acid reduced significantly the synovial fluid PGE2 concentrations. Diclofenac and indomethacin also reduced significantly the synovial TxB2 concentrations.

Is hyperventilation a physiologically significant stimulus for prostaglandin release in the human pulmonary vascular bed?

The influence of hyperventilation on the pulmonary prostaglandin (PG) release was studied in healthy volunteers. Hyperventilation was forced by adding 8% CO2 to the inhaled air and arterial and mixed venous blood was sampled for radioimmunoassays of 6-keto-PGF1 alpha and PGE2. The increased ventilation did not alter the arterio-venous PG concentration differences suggesting that hyperventilation accompanying the activation of chemoreceptors is not a physiologically significant stimulus for the pulmonary PG release in man.

Effects of a prostacyclin analog iloprost on kidney function, renin-angiotensin and kallikrein-kinin systems, prostanoids and catecholamines in man

Iloprost (ZK 36 374), a stable analog of carbaprostacyclin, was infused for 72 h to nine patients with advanced obliterative arterial disease. Iloprost caused a marked vasodilation and a compensatory increase in cardiac output. The glomerular filtration rate increased by 45% and tubular reabsorption of sodium and water were reduced by 80% and 107%, respectively. The urine excretion rate increased by 122%. Tubular handling of potassium and calcium were not influenced by iloprost but magnesium reabsorption was stimulated. The renin-angiotensin system was not activated while serum angiotensin converting enzyme activity was decreased. Kallikrein excretion in urine was increased 4.4-fold but plasma kininogen, a substrate for kallikrein in producing vasoactive kinins, was unaffected by the drug. Plasma levels of 6-keto-PGF1 alpha and TxB2 were decreased and their excretion in urine increased. Plasma catecholamines were not changed by iloprost. Several of the changes persisted for at least the first postinfusion day. The results indicate that iloprost increases urine excretion rate by increasing glomerular blood flow and by inhibiting sodium and water reabsorptions. The kinin-forming system, but not the renin-angiotensin system or plasma catecholamines, may be activated. The decrease in plasma level of prostanoids can be, at least partly, due to their increased excretions in urine.

Effect of propranolol, practolol and atenolol on human platelet thromboxane formation and plasma levels of prostaglandins 6-keto-F1 alpha and E2

The effects of three different beta-adrenergic blocking drugs, propranolol, practolol and atenolol on platelet thromboxane production and the release of prostacyclin and prostaglandin E2 into the circulation were investigated in healthy volunteers. The beta-adrenergic antagonists were administered intravenously at equipotent doses. The serum TxB2 levels after whole blood clotting and the arterial and venous plasma concentrations of 6-keto-PGF1 alpha and PGE2 were measured before and during a 60 min period after the administration of the drugs, using radioimmunoassay. Practolol and atenolol elicited a significant decrease in platelet thromboxane formation but remained without effect on plasma 6-keto-PGF1 alpha and PGE2 levels. In contrast, propranolol did not influence serum TxB2 concentrations but induced a significant increase in plasma content of 6-keto-PGF1 alpha and PGE2. The results indicate that beta-adrenergic antagonists alter the balance between the proaggregatory, vasoconstricting and antiaggregatory, vasodilating prostanoids in the human cardiovascular system. Although the direction of the action of these drugs seems to differ depending on the selectivity of the beta-adrenoceptor blocking properties the net effect of this action should be beneficial.

Plasma levels and urinary excretion of prostaglandins in patients with rheumatoid arthritis

No significant differences were found in plasma concentrations and urinary excretion of prostaglandin E2 (PGE2), 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TxB2), between rheumatoid arthritis patients and controls. However, urinary excretion of PGEe and 6-keto-PGF1 alpha tended to be greater and plasma levels of TxB2 lower in rheumatoid arthritis. Plasma concentrations and urinary excretion showed no marked circadian variation, although night or morning values were slightly lower. Plasma and urine prostaglandins do not correlate with clinical symptomatology in rheumatoid arthritis.