Cyclooxygenase and lipoxygenase metabolite generation in nasal polyps

A role of prostaglandins (PGs) and leukotrienes (LTs) in the pathogenesis of nasal polyps has been recently suggested. Cyclooxygenase (CO) products (thromboxane B2, PGE2 and 6-keto PGF1 alpha) and lipoxygenase (LO) products (LTB4 and LTC4) were investigated by radioimmunoassay in polyps, hypertrophic turbinates and nasal mucosa from 14 patients with non-allergic (n = 6), allergic chronic rhinitis (n = 6) and aspirin-sensitive asthma (ASA) (n = 2), who underwent polypectomy. In all tissues CO metabolite levels were found higher than LO products (P < 0.01). Nasal polyps showed a significantly lower (P < 0.05) arachidonic acid (AA) metabolism in comparison to nasal mucosa. In polyps of allergic patients significantly higher LTB4 levels (P < 0.001) and a tendency to produce higher amounts of CO products in comparison to non-allergic subjects were observed, whereas in turbinates of non-allergic patients LT levels were significantly higher in comparison to those of allergic ones (P < 0.01). In ASA patients a decreased CO/LO ratio was found supporting the hypothesis of an imbalance of AA metabolism in this syndrome. These findings seem to indicate that the occurrence of nasal polyps may represent the result of different chronic inflammatory stimuli, regulated in part by AA metabolites.

Effects of estrogen replacement therapy on thrombin generation

The aim of this study was to investigate the hemostatic system in menopausal women before and after three months of treatment with transdermal estradiol (TTS 50, 50 micrograms/die, n = 13) or coniugated equine estrogen (CEE, 0.625 mg/die, n = 9) by evaluating : beta-thromboglobulin, platelet factor 4, factor VIIag, factor VIIc, fibrinopeptide A-FPA-, thrombin-antithrombin-TAT-complexes, antithrombin-AT-activity, protein C, plasma fibrinolytic activity (euglobulin clot lysis time), plasminogen and antiplasmin activity. FPA levels significantly increased during TTS 50 treatment (p < 0.001) while protein C showed a slight but significant decrease in both treatments (TTS 50 p < 0.001, CEE p < 0.05). TAT complexes and AT were found unaltered. Platelet function and fibrinolytic activity did not significantly change. A significant relationship between FPA and estradiol levels, which were significantly increased during. TTS 50 therapy, was found (r = 0.40, p < 0.05). These findings indicate that unopposed estradiol given by transdermal route induces a slight but significant blood clotting activation, which seems strictly related to its biological activity.

Endogenous estrogen and acetylcholine-induced vasodilation in normotensive women

Acute exogenous estrogen administration enhances endothelial function in postmenopausal women. To evaluate the effect of endogenous estrogen on endothelium-dependent vasodilation, in 10 fertile normotensive women (age range 45 to 51 years) we studied the changes in forearm blood flow (strain-gauge plethysmography) induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, 1.5 micrograms.100 mL-1.min-1), an endothelium-dependent vasodilator, or sodium nitroprusside (1, 2, 4 micrograms.100 mL-1.min-1), an endothelium-independent vasodilator, in basal conditions and within 1 month after ovariectomy. As control subjects, 10 matched healthy women were also evaluated. In basal condition, vasodilation to acetylcholine and sodium nitroprusside was similar in patients and control subjects. Ovariectomy was followed by endogenous estrogen deprivation (from 71.6 +/- 31.3 to < 12 pg/mL) and was associated with a significant (P < .01) reduction in acetylcholine-induced vasodilation compared with baseline (maximum percent increase in forearm blood flow: baseline 568.2 +/- 47.1%; ovariectomy 309.5 +/- 37.4%); the response to sodium nitroprusside was unaffected by ovariectomy (maximum percent increase in forearm blood flow: baseline 526.4 +/- 36.5%; ovariectomy 454.7 +/- 47.2%; P = NS). In 6 of 10 patients, the study was repeated after 3 months of estrogen replacement therapy (17 beta-estradiol, 50 micrograms/d by transdermal patches). Exogenous estrogen restored acetylcholine-induced vasodilation (maximum percent increase in forearm blood flow: 548.9 +/- 43.1%; P < .01 versus ovariectomy), which was no longer different from baseline, whereas the response to sodium nitroprusside was not affected (maximum percent increase in forearm blood flow: 480.2 +/- 39.3%; P = NS). These results suggest a protective role of endogenous estrogen on endothelium-dependent vasodilation in the forearm vascular bed of normotensive women.

Menopause is associated with endothelial dysfunction in women

To evaluate the effect of endogenous estrogens on endothelial function in humans, we examined whether menopause is associated with impairment in endothelium-dependent vasodilation in normotensive and essential hypertensive women. In 73 normotensive subjects (37 women, 36 men) and 73 hypertensive patients (36 women, 37 men), we studied endothelial function by measuring forearm blood flow modifications (strain-gauge plethysmography) induced by intrabrachial acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 micrograms/100 mL per minute), an endothelium-dependent vasodilator, and sodium nitroprusside (1,2, and 4 micrograms/100 mL per minute), an endothelium-independent vasodilator. Women younger than 45 years had normal menstrual cycles. In essential hypertensive patients, responses to acetylcholine but not to sodium nitroprusside were significantly (P < .001) reduced compared with responses in normotensive subjects. Moreover, in both groups, vasodilation to acetylcholine showed a marked negative correlation with advancing age (normotensive subjects: r = -.88, P < .001; hypertensive patients: r = -.87, P < .001). In contrast, vasodilation to sodium nitroprusside showed a less evident negative correlation with advancing age (normotensive subjects: r = -46, P < .01; hypertensive patients: r = -.48, P < .01). However, in normally menstruating normotensive women, no endothelial dysfunction was observed, and age-related impairment in endothelium-dependent vasodilation was evident only after menopause. In normally menstruating hypertensive women, aging was associated with endothelial dysfunction although the deterioration of endothelium-dependent vasodilation was less marked than that in men. In contrast, after menopause, the age-related endothelial dysfunction in hypertensive women was similar to that observed in men. Finally, no sex-related difference in the response to sodium nitroprusside was observed in either normotensive subjects or essential hypertensive patients. Age-related endothelial dysfunction is attenuated in premenopausal normotensive and hypertensive women compared with men, whereas no sex-induced difference is observed after menopause, suggesting a protective effect of endogenous estrogens on endothelial function.

[A resurgence of rheumatic fever. New causes or old attitudes?]

Bearing in mind that in the last years there has been an increase in rheumatic fever episodes, the authors evaluate the cases recently observed in the department. The data of 3 children born and living in Portugal, the first known outbreak of rheumatic fever observed between June 93 and March 94, were examined. One case presented polyarthritis, another polyarthritis and carditis and the third chorea and carditis. In just one case was the diagnosis of rheumatic fever considered in the beginning, and over-all, failures in the diagnosis and treatment of tonsillitis, and in echocardiographic diagnosis were detected. In view of these examples, the authors conclude that the increasing incidence and morbidity of rheumatic fever is more probably due to forgetfulness of old attitudes than to new causes. Delay in the diagnosis and errors in secondary prophylaxis may influence long term results.

The long-term treatment of social phobia with moclobemide

Patients meeting the social phobia criteria of the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) on the DSM-III-R Structured Clinical Interview (n = 101) entered a long-term moclobemide treatment study. These patients were treated for 2 years with moclobemide (phase I) followed by drug withdrawal, in most cases abruptly (phase II). Those who relapsed entered phase III for a further period of 2 years of treatment. During phase I 40 patients (39.6%) withdrew due to inefficacy or relapse. Two patients were removed from the study because of other diagnoses (borderline or schizophreniform). At the end of phase I the remaining patients (58.4%) were rated as not ill (45.5%) or minimally ill (11.9%). Effort was taken to achieve the maximum dose of moclobemide (750 mg/day) and the mean (+/-SD) dose was 723.3 +/- 67.7 mg/day (month 21). A marked decrease in symptoms in the patients who responded was recorded on the Liebowitz Scale for Social Phobia, Clinical Global Impressions. Hamilton Anxiety Scale and Hamilton Depression Scale. Non-response was mainly associated with co-morbidity, especially alcohol abuse, axis II disorders, and a history of major depression or secondary dysthymia. The drug was well tolerated; the more frequent side effects were mild and occurred mainly in the first 2 months of phase I, including nausea, headaches or insomnia. In phase II there was a relapse rate of 88% and 51 patients entered phase III; these patients are still being treated.

[Molecular pathobiology in heart failure]

Heart failure is a pathophysiological state resulting from disturbed cardiac function. It is based on complex molecular processes, many of which are not fully understood. During heart failure adaptive mechanisms, that reinstall altered cardiac function, are activated. The main mechanisms are: a) Alteration of the structure and composition of myocytes by myocardial hypertrophy, reexpression of fetal and neo-natal proteins and the expression of certain proto-oncogenes; b) Activation of the neuroendocrinal system, specifically the sympathetic nervous system, renin-angiotensin-aldosterone system and vasopressin release; c) Activation of autocrine and paracrine systems. However, when these systems are activated beyond a certain limit they contribute to heart failure aggravation. This can also be promoted by alteration of the calcium metabolism inherent in heart failure. The synthesis of the counterregulator atrial natriuretic factor is also increased.

Increased thromboxane A2 production at primary tumor site in metastasizing squamous cell carcinoma of the larynx

In order to evaluate the possible role of prostaglandins (PG) in invasion and metastasis of malignant cells in larynx carcinoma, arachidonic acid (AA) metabolite production by tumor tissue, peritumor tissue and node metastasis was investigated in comparison to that by healthy mucosa and unaffected lymph nodes. The study was performed by evaluating PGE2, 6ketoPGF1 alpha and thromboxane B2 (TXB2) production by radioimmunoassay in specimens from eight patients who underwent surgical treatment. The highest rate of AA metabolism was observed in peritumor tissue. PGE2 was the main metabolite produced in all tissues and its levels were significantly higher than those of 6ketoPGF1 alpha and TXB2 (p < 0.05). 6ketoPGF1 alpha production was higher (p < 0.01) than that of TXB2 and did not significantly change among the different tissues. TXB2 production was significantly increased (p < 0.05) by peritumor tissue as compared to healthy mucosa. The ratio between TXB2 and 6ketoPGF1 alpha production was found to be almost twofold higher in tumor tissue, peritumor tissue, metastatic and non-metastatic lymph nodes as compared to control tissue. The lowest AA metabolism was found in affected lymph nodes. These findings demonstrate a different AA metabolism at primary tumor sites in comparison to healthy mucosa suggesting a prometastatic role of TXB2 and supporting the hypothesis of the occurrence of an imbalance between TXB2 and 6ketoPGF1 alpha production in favouring metastatic spread.

Adjustable nylon ties for abdominal wall closure

A study in 64 patients with a high risk of wound dehiscence or eviscerated wounds or in whom repeat laparotomies for peritoneal lavages due to sepsis were planned was accomplished using adjustable nylon ties for the closure of the abdominal wall, either as retention sutures or as one-layer sutures. The adjustable nylon ties are described, as well as the technique for placing and adjusting them. It is concluded that the adjustable nylon ties can substitute advantageously for the conventional retention sutures since the former are wider, easy to place, and can be readjusted to the point that they can be opened completely if it is necessary and then closed again. This is especially useful when repeat laparotomies for peritoneal lavages are required in patients with intra-abdominal sepsis.

Monocyte tumor necrosis factor production in head and neck squamous cell carcinoma

Changes in monocyte and macrophage function have been demonstrated in patients with head and neck squamous cell carcinoma. The purpose of this study was to evaluate tumor necrosis factor (TNF) production by activated monocytes from patients with head and neck squamous cell carcinoma and to evaluate its relation to cancer stage, weight loss, and performance status. Monocytes from patients (n = 10) and controls (n = 10) were isolated from peripheral blood mononuclear cells by plastic adherence and incubated with lipopolysaccharide (10 micrograms/mL). The TNF concentration of supernatants was assayed by TNF alpha-specific immunoassay. The TNF production by monocytes from head and neck squamous cell carcinoma patients was significantly higher (P less than .001) than those of controls. No significant relationship was found to cancer stage, weight loss, and performance status. These findings indicate that, in head and neck squamous cell carcinoma patients, an increased TNF production by activated monocytes takes place which does not correlate with cancer stage, cancer-related weight loss, and performance status.

Changes in thromboxane A2 generation and plasma lipid pattern in pseudomenopause induced by gonadotropin releasing hormone (GnRH) analogue buserelin

An increased risk of cardiovascular disease has been found in postmenopausal women in comparison to premenopausal women. The aim of this study was to investigate platelet function, blood clotting and plasma lipid levels in 12 women with a condition of hypoestrogenism, similar to the postmenopausal status induced by treatment with the GnRH analogue buserelin for uterine leiomyoma. Platelet aggregation in whole blood and platelet-rich plasma (PRP), serum thromboxane (TX) B2 production, fibrinopeptide A (FPA) plasma levels and plasma lipid pattern were measured before and after 13 weeks of buserelin treatment. No changes of platelet aggregability were found either in whole blood or PRP. Serum TXB2 generation increased significantly after 13 weeks of therapy (p less than 0.001). No signs of increased thrombin generation were found, as indicated by unchanged FPA plasma levels. Total cholesterol plasma levels were found increased after 13 weeks, LDL cholesterol levels showed a tendency to increase although not significantly. HDL cholesterol and triglyceride concentrations were unaffected. The changes of arachidonic acid metabolism and lipid pattern suggest that buserelin treatment may induce a condition of increased thrombotic risk even if the lack of enhanced thrombin generation and increased platelet aggregability indicates that no blood clotting activation occurs.

Cyclooxygenase and lipoxygenase metabolite synthesis by polymorphonuclear neutrophils: in vitro effect of dipyrone

Functional activity of polymorphonuclear neutrophils (PMN) is associated with the metabolism of Arachidonic Acid (AA) released from membrane phospholipids. In this study the in vitro effect of dipyrone, a non steroidal anti-inflammatory drug, on the production of AA metabolites through cyclooxygenase (CO) and lipoxygenase (LO) pathways by stimulated PMN has been investigated. PMN isolated by counterflow centrifuge elutriator were greater than 98% pure and viable. Metabolite production was evaluated by RIA of Thromboxane A2 (TxA2), Prostaglandin E2 (PGE2), Leukotriene B2 (LTB4) and Leukotriene C4 (LTC4) after PMN stimulation with calcium ionophore A 23187 (20 microM). The levels of beta-thromboglobulin (RIA) lower than 5 ng/ml allowed us to rule out activation of residual contaminant platelets. In these experimental conditions, in the absence of dipyrone the products (ng/10(6) cells) of AA metabolism were LTB4 (3.51 +/- 0.22), LTC4 (0.81 +/- 0.08), TxB2 (0.144 +/- 0.025) and PGE2 (0.150 +/- 0.017). Incubation with dipyrone induced changes of PGE2 and TXB2 production in a dose dependent fashion (r = 0.83 and r = 0.87, p less than 0.001), obtaining already at the lowest drug concentration (5 micrograms/ml) a significant inhibition (33 and 40% for TxB2 and PGE2 p less than 0.005). No significant changes of LTB4 and LTC4 production have been observed. The results of this study indicate that dipyrone relevantly affects CO metabolite synthesis by stimulated PMN at concentrations comparable to those reached in therapeutic use. The inhibition of PGE2 synthesis which is present in inflamed tissues and actively participates in inflammatory reactions, could contribute to the therapeutic anti-inflammatory action of dipyrone.

Sex related differences in platelet TxA2 generation

Platelet lipid composition, c arachidonic acid (AA) metabolism by platelets (stimulated with thrombin), serum thromboxane (Tx)B2 production and plasma lipid composition were investigated in 53 healthy females (18-45 years) and 65 males (19-45 years) with similar dietary habits. In males, serum TxB2 production and cholesterol platelet membrane levels were found significantly higher (p less than 0.001 and p less than 0.05) than in females. No differences were observed between the two groups in the AA conversion through cyclo-oxygenase and lipoxygenase pathways or in the platelet phospholipid fatty acid composition. These findings indicate that in males the platelet proaggregatory capacity is greater than in females and the higher platelet TxB2 production does not depend on a larger AA availability or on enzyme activation for its conversion. The increased TxB2 production may be, at least in part, induced by functional differences such as a different membrane cholesterol content inducing, in its turn, an increased microviscosity and/or higher number of platelet receptors for thrombin.

Effects of long-term gestodene-containing oral contraceptive administration on hemostasis

The purpose of this study was to evaluate the behavior of the hemostatic system during treatment with gestodene-containing oral contraceptives in monophasic (SHD 356, n = 15) and triphasic (SHD 415, n = 15) formulations. No changes in platelet (beta-thromboglobulin, platelet aggregate ratio, and megathrombocyte) and routine clotting assays were observed. Factor VIIc/factor VIIag ratio and fibrinopeptide A values showed a significant (p less than 0.005) increase after three cycles of both treatments. A slight, significant increase (p less than 0.01) in antithrombin III activity was observed during triphasic treatment. Protein C was unchanged. Fibrinolytic activity and plasminogen levels were significantly increased (p less than 0.05 and p less than 0.001). After 6 and 9 months, the factor VIIc/factor VIIag ratio was still significantly enhanced, whereas fibrinopeptide A values significantly (p less than 0.05) decreased, even if they were higher (p less than 0.05) than basal values. The persistence of factor VII activation without enhanced thrombin formation after long-term use of oral contraceptives suggests that at that time the activity of antithrombotic mechanisms counteracts the prothrombotic tendency, thus helping to minimize unwanted side effects on hemostasis during long-term drug administration.

Prostaglandins in squamous cell carcinoma of the larynx: tumor and peritumor synthesis

Prostaglandin (PG) E2, 6ketoPGF1 alpha and Thromboxane B2 (TxB2) production by the tumor, peritumor and control tissue were investigated in specimens from patients (n = 11) with squamous cell carcinoma of the larynx, in relation to the extension and infiltration of the neoplasm and to the presence of inflammation, fibrosis and necrosis. In all specimens detectable amounts of 6ketoPGF1+ and TxB2 were found, but the predominant metabolite was PGE2. No differences in the levels of TxB2 and 6ketoPGF1 alpha were observed, but the only patient with lymphnodal involvement showed the lowest levels of 6ketoPGF1 alpha both in tumor and peritumor tissue. Higher amounts (p less than 0.05) of PGE2 were synthesized by peritumor tissues in comparison to control mucosa and tumor tissue independently of the occurrence of reactive infiltration. PGs synthesis did not correlate with inflammation, fibrosis, necrosis or staging of the neoplasm. However the two cases in stage T4 showed PGE2 generation at the highest levels both in neoplastic and perineoplastic tissue. These findings indicate that in squamous cell carcinoma of the larynx an increased production of PGE2 occurs, stemming not only from inflammatory cells but at least in part from neoplastic cells. This suggests that the study of arachidonic acid metabolism may contribute to characterization of the primary cancer and lead to better understanding of the mechanisms of tumor growth and diffusion.

Activity of dipyrone on intraplatelet arachidonic acid metabolism: an in vitro study

The effects of dipyrone on platelet cyclooxygenase and lipoxygenase were investigated in vitro by the study of 1-14C arachidonic acid (AA) conversion by high performance liquid chromatography (HPLC) on washed platelets at seven different drug concentrations (from 5 to 300 micrograms/ml). The effects of dipyrone on thromboxane (TX) B2 generation from endogenous AA were also studied in platelet-rich plasma and in washed platelets by radioimmunoassay. In the study of 1-14C AA metabolism the inhibitory concentration (IC) 50 for TXB2 was 40 micrograms/ml. However, at the lowest drug concentration (5 micrograms/ml) a slight but significant inhibition was found (25.3%, P less than 0.001) and a complete one at 300 micrograms/ml. A relationship between TXB2 inhibition and log drug concentration was found (r = 0.97, P less than 0.001). Lipoxygenase (LO) activity showed an increase of 45.9% at 20 micrograms/ml and of 251.5% at the highest concentration (r = 0.97, P less than 0.001). The inhibition of TXB2 generation from endogenous AA by washed platelets was of the same order of magnitude of the inhibition of TXB2 production from exogenous 1-14C AA. Our results indicate that dipyrone affects intraplatelet AA metabolism at very low concentrations, however its activity, on a molar ratio basis, appears to be lower than that of other non-steroidal anti-inflammatory drugs.

Altered membrane fatty acid composition and increased thromboxane A2 generation in platelets from patients with diabetes

Lipid composition of platelet membranes and thromboxane A2 (TxA2) generation by platelets were investigated in 42 diabetic patients (14 with macroangiopathic complications, 10 with microangiopathy and 18 without vascular complications) and in 42 clinically healthy subjects of similar age. All subjects were on a similar dietary regimen and the adherence to diet was checked by analysis of red blood cell lipids. Platelets from all groups of diabetic patients produced increased amounts of TxA2 than platelets from controls (at least p less than 0.01) and patients with macroangiopathy (p less than 0.01). Platelet cholesterol and total platelet phospholipids were higher in patients with macroangiopathy, while the relative percentage of the different phospholipid fractions in platelet membrane and their saturated and unsaturated fatty acids were similar in the different groups. Arachidonic acid (AA) content in phosphatidylcholine (PC) was found to be significantly higher in diabetic patients than in controls (at least p less than 0.005). Moreover patients with macroangiopathy had higher AA (p less than 0.001) and lower eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) levels in PC (p less than 0.001) than the other groups of patients and controls.

Increased thrombin generation in normal pregnancy

The aim of this longitudinal study was to evaluate whether an increased thrombin generation takes place in normal pregnancy by determining fibronopeptide A plasma concentration in 24 women at three stages of gestation. The activity of the main blood clotting inhibitors, antithrombin III and protein C., and platelet agregability were also investigated. Our study showed a significant rise of fibrinopeptide A plasma levels already manifest at the first trimester. Antithrombin III activity was found to slightly but significantly decrease during pregnancy, whereas protein C levels showed a moderate, significant increase. A slight platelet activation was observed in the second and third trimester. These findings indicate that during pregnancy a new equilibrium of blood clotting system arises, shifted to a hypercoagulable state which leads to the increased risk of thromboembolism observed in pregnancy.