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Oxygen free radicals (OFR) are postulated to play a role in the pathogenesis of acute pancreatitis. The aim of this work was to examine the role of xanthine oxidase in the generation of OFR and the activity of the endogenous defense mechanisms as reflected by pancreatic superoxide dismutase (SOD) activity in a model of edematous pancreatitis induced in rats by administration of cerulein at supramaximal doses, as well as in necrohemorrhagic model induced by intraductal administration of sodium taurocholate. Comparison between these two models of pancreatitis suggests important differences in origin and importance in the evolution of injury. In necrohemorrhagic pancreatitis OFR can be produced by xanthine oxidase activity probably associated to cell death. By contrast, in cerulein induced pancreatitis, other sources of oxygen free radicals, such as inflammatory cells, can be of more importance.

The implication of eicosanoid metabolism and its relationship with oxygen free radical production in the process of ischemia-reperfusion associated with rat pancreas transplantation has been explored in this study. For this purpose male Sprague-Dawley rats were classified as follows: group I, control animals not surgically manipulated; group II, pancreas transplantation, after 30 min preservation in UW solution; group III, pancreas transplantation after 12 h preservation under the same conditions; group IV, same as group III but with administration of SOD 5 min prior to organ revascularization. The results show post-transplantation increases in 6-keto-PGF1 alpha, TXB2, LTB4 and 12-HETE in pancreatic tissue independent of preservation time. The fact that SOD administration could reverse these increases even though an efficient xanthine oxidase irreversible inhibitor such as allopurinol was present in the preservation solution suggests that eicosanoid generation in the recipient rat would be mediated by an oxygen free radical dependent mechanism not exclusively dependent on endothelial xanthine oxidase activity.

Spontaneous contractile activity, glucose (Glu), glycogen (GLY), triglyceride (TG) metabolism and eicosanoid production, was evaluated in isolated uterine strips from control and non-insulin-dependent diabetic rats on day 10 of pregnancy. Metabolism of Glu, levels of GLY and TG and eicosanoid production were also studied in day 10 embryos obtained from both experimental groups. "In vitro" isometric developed tension (IDT), was similar at 0 hr in control and diabetic uterine preparations, but IDT was decreased after a 60 min incubation in the diabetic group. The frequency of contractions (FC) was similar at 0 hr and after 60 min incubation in both experimental groups. On the other hand, the production of 14CO2 from U14C-glucose was lower in isolated uteri and embryos obtained from diabetic rats than in controls. Initial TG levels were similar in uteri isolated from control and diabetic rats, and higher in embryos obtained from diabetic mothers than in controls. Levels of TG in uterine strips suspended in Glu or Glu-free medium did not differ at 0 hr or at 60 min either in controls or in diabetic rats. On the contrary GLY levels in uterine strips from diabetic animals were higher than in controls, whereas in embryos from diabetic mothers GLY levels were similar to controls. Levels of GLY in uterine strips from controls and diabetic animals decreased after 60 min incubation only in the absence of Glu in the incubation medium. Production of PGE2, PGE1, 6-keto-PGF1 alpha, PGF2 alpha, TXB2 and LTB4 was studied in uterine strips and embryos obtained from control and diabetic rats. No differences were found between control and diabetic uterine prostanoid production, but lower production of LTB4 was observed in diabetic uteri. However production of PGE2 and PGF2 alpha was greater in embryos obtained from diabetic mothers than in controls. In this study, we observed lower uterine metabolic alterations than in the pancreatectomized diabetic rat model studied previously, but important anomalies in the embryos obtained from non-insulin-dependent diabetic mother were found.

Eicosanoid metabolism and its relationship with platelet-activating factor and oxygen free radical production in rat pancreas transplantation has been studied herein. Male Sprague-Dawley rats were classified in 4 experimental groups (n = 8 each) as follows: group 1, control; group 2, pancreas transplantation, after 12 hr of organ preservation in University of Wisconsin solution; group 3, same as group 2 with desferrioxamine administration before revascularization of the organ in the recipient rat; and group 4, same as group 3 with administration of a platelet-activating factor antagonist (BN-52021). The results show post-transplantation increases in eicosanoid production in pancreatic tissue. The fact that desferrioxamine and BN-52021 administration could reverse increases in thromboxane B2, leukotriene B4, and 12-hydroxyeicosatetraenoic acid but only BN-52021 affected 6-keto-PGF1 alpha levels suggests the existence of a close relationship between platelet-activating factor and oxygen free radical in eicosanoid production in pancreas transplantation and it points to a differential role of metabolites produced by circulatory cells and endothelial cells.

Changes in endogenous pancreas production of prostaglandins D2, F2 alpha, E2, and E1 in early stages of acute necrotizing pancreatitis induced by intraductal administration of 3.5% sodium taurocholate have been determined by radioimmunoassay of chromatographically purified tissue extracts. For this purpose 18 male Wistar rats were randomized in three groups: control, pancreatitis, and pancreatitis plus indomethacin. Pancreas tissue samples were obtained 5 min after pancreatitis induction. In the pancreatitis-induced group, prostaglandins D2, F2 alpha, and E2 show significantly increased tissue levels relative to the controls whereas prostaglandin E1 remains unmodified. These results suggest a role for series 2 prostaglandins in the earlier stages of pancreatitis.

Background: We evaluated the effect of furosemide on allergen-induced rhinitis in a double-blind, crossover, placebo-controlled experiment., Methods: Fourteen patients with rhinitis who were allergic to house dust were nebulized with an intranasal dose of 20 mg of furosemide or placebo before allergen challenge with an extract of Dermatophagoides pteronyssinus (100 BU). Clinical evaluation and nasal lavages with normal saline solution were performed at baseline; after placebo-furosemide nebulization, and at 10, 30, and 60 minutes after allergen challenge. Number of sneezes and a composite symptom score were recorded to evaluate clinical response. Prostaglandin E2 (PGE2), PGD2 peptide leukotrienes and 15-hydroxy, 5,8,11,13-eicosatetraenoic acid (15-HETE) were measured by radioimmunoassay in nasal lavages. Cells were counted and classified as epithelial cells, neutrophils, eosinophils, and others., Results: No differences in either clinical symptoms or cell influx after allergen challenge were found between furosemide and placebo groups. PGE2 levels did not change after provocation, and furosemide had no effect on its production. Ten minutes after antigen challenge there was a marked increase of PGD2 (p < 0.01), peptide leukotrienes (p < 0.01), and 15-HETE (not significant) on both study days. However, no significant differences in the release of eicosanoids were found between furosemide and placebo groups., Conclusions: Our observations in the nasal mucosa suggest that furosemide has no effect on the release of proinflammatory and bronchoconstrictor metabolites (PGD2, peptide leukotrienes, and 15-HETE). In contrast to bronchial asthma, allergen-induced rhinitis was not effectively prevented by furosemide.

A commercial automated solid-phase extraction system for cyclooxygenase arachidonic acid metabolites in urine samples has been evaluated. Comparison of manual and automatic batch (36 samples) extraction procedures for tritium labelled prostanoids added as tracers to urine samples has shown equivalent results with recoveries greater than 90% for prostaglandins E2, F2alpha and 6-keto prostaglandin F1alpha as well as thromboxane B2. Analyte stability is not affected by the automated procedure, which uses less solvents and has a faster overall processing time than the manual method. The automated system has been applied to the extraction of prostanoids in urine samples from workers exposed to dichloroethane.

This study was carried out to investigate the proportion of the 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and thromboxane B2 (TXB2) alteration that is due to ischemia in pancreas transplantation against the proportion due to reperfusion. For this purpose, Lewis rats were divided in three experimental groups: Group I = Control, Group II = Donor pancreas subjected to 15 minutes of cold ischemia, Group III = Same as group II but pancreas were transplanted to the recipient individual and then subjected to reperfusion. The results indicate that increases in pancreas 6-keto PGF1 alpha occur as a consequence of cold ischemia while TXB2 remains unchanged. When blood flow was restored, 6-keto PGF1 alpha remained unchanged compared to the ischemic group while pancreatic levels of TXB2 were significantly increased. These results suggest a different induction of prostanoid metabolism during ischemia and reperfusion in pancreatic tissue.

A method for the determination of 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) by gas chromatography-mass spectrometry (GC-MS) in samples obtained from healthy subjects by nasal lavage is presented. HETEs were extracted from samples obtained by nasal lavage using C18 solid-phase cartridges. The purification of 12-HETE and 5-HETE was carried out in two consecutive steps of purification by reversed-phase high-performance liquid chromatography. Methylated and trimethylsilylated fractions were separated by GC-MS with electron-impact ionization. The production of 12-HETE by human nasal mucosa was confirmed by GC-MS.

Prostaglandin E2, thromboxane B2 and leukotriene B4 monocyte production have been determined in human immune deficiency virus (HIV)-infected drug users (n = 36) and healthy subjects (n = 29). Eicosanoids were extracted from the incubates using C18 solid-phase cartridges and determined by radioimmunoassay. An enhanced production of prostaglandin E2 and thromboxane B2 was detected in monocytes from HIV-positive drug users whether or not they had been previously stimulated with zymosan. Concomitant leukotriene B4 increases were not observed. The results reported in this paper indicate that altered cyclooxygenase arachidonic acid metabolism in monocytes from HIV-infected drug users is associated with the severe cellular immunodysfunction characteristic of AIDS. In contrast, leukotriene B4 does not seem to play a role in AIDS-associated immunosuppression.

Free radical species have been implicated as important agents in ischemia-reperfusion injury associated to transplantation procedures. This study was carried out to investigate the possible relationship between phospholipase A2 activity (PLA2), lipoperoxidation, and the changes in arachidonic acid metabolism during ischemia reperfusion injury in pancreas transplantation, as well as the effect of a free radical scavenger such as superoxide dismutase on these changes. For this purpose male Lewis rat groups (n = 7) were classified as follows: group I--control; group II--syngenic pancreas transplantation after 15 min preservation in Collins solution at 4 degrees C; group III--syngenic pancreas transplantation after 18 hr preservation in the same conditions; group IV--same as III but with administration of SOD (i.v.) immediately before revascularization in the recipient rat. The results indicate that significant increases in PLA2 activity and lipoperoxide levels occur concomitantly with an increase of thromboxane B2 (TXB2) and 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) in pancreatic tissue after pancreas transplantation. The counteracting effect of a free radical scavenger such as SOD supports the role of oxygen free radicals (OFR) mediating activation of PLA2 and subsequent formation of eicosanoids in pancreas transplantation.

An improved analytical method for the simultaneous solid-phase extraction of arachidonic acid metabolites in biological samples is described. The major aim of the work was to define the cause of the different recoveries reported in the literature for leukotrienes and hydroxyeicosatetraenoic acids. We used nasal lavages to carry out a comparative study of solid-phase extraction parameters of practical importance in securing good recoveries of leukotrienes and hydroxyeicosatetraenoic acids from biological samples. We evaluated the influence of the pH of the sample, the pH of the water used to wash the extraction cartridge before elution of the adsorbed analytes, the comparative behaviour of commercially available octadecyl adsorbents and the influence of the concentration-evaporation step on final recoveries. Data thus obtained show that there is no significant difference in results when the samples and the water used to wash the cartridge before analyte elution are adjusted to pH values ranging between 4.0 and 7.4. Below pH 4.0, losses may be significant. Furthermore, recoveries can be very much dependent on the type of solid-phase cartridge material and on the eluent evaporation method, especially with regard to aqueous phase removal.

We have investigated the duration of the inhibitory effects of aspirin in eight healthy volunteers after oral administration of a single 500 mg dose. Prostaglandin E2, D2 and leukotriene C4 levels in nasal lavage fluid were measured by radioimmunoassay without purification by high performance liquid chromatography. The inhibitory effects of aspirin on eicosanoid synthesis were maximum between 1 h to 24 h, showing total recovery within 3-5 days. LTC4 synthesis was not modified by aspirin.

This work undertakes the study of changes in urinary, plasmatic and tissue levels of Thromboxane B2 (TXB2) as well as in tissue Prostaglandin E2 (PGE2) after pancreas transplantation and the effect of superoxide dismutase (SOD) on these changes. For this purpose, streptozotocine induced diabetic rats were subjected to pancreas transplantation. Experimental groups were classified as follows: Group I: Control; Group II: Animals subjected to 15 min of pancreas arterial flow occlusion followed by reperfusion; Group III: Syngenic pancreas transplantation after 12 hours of organ preservation; Group IV: Same as III, but with additional SOD (13 mg/kg) pretreatment. The results indicate that significant increases of PGE2 and TXB2 levels occur as a consequence of the surgical removal, preservation and implantation of the organ. For TXB2 these increases, immediate in plasma and tissue, are not detected in urine until 24 hours after transplantation of the pancreas. The release of TXB2 and PGE2 was effectively prevented in the SOD treated group supporting the role of oxygen free radicals and lipid peroxidation in the processes of ischemia-reperfusion associated to transplantation of the pancreas.

The effect of lysine salicylate, flurbiprofen and sulphasalazine on human seminal prostaglandin profiles of six normal individuals was studied. All of them were treated with pharmacological doses of the three agents for four days with rest periods of eighteen days in between. Sulphasalazine produced less prostaglandin (PG) inhibition relative to the other two antiinflammatory drugs but in contrast only sulphasalazine induced sperm changes. Infertility status associated with the ingestion of therapeutic levels of sulphasalaziane is not directly related to the endogenous PGEs and 19-OH PGEs, the major prostanoids in human semen. PG determinations were carried out using gas chromatographic (GC) techniques.