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Results 301 - 350 of 1138
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Mandel K G - - 1994
This study involved a comparison of activity of several long-chain fatty acids (arachidonic acid, dihomo-[gamma]-linolenic acid, linoleic acid, and oleic acid) for protection against gastric mucosal damage elicited by taurocholic acid, acidified aspirin, and ethanol in rats. Each damaging agent induced gastric mucosal lesions in the corpus. Mucosal damage was ...
Morrow J D - - 1994
BACKGROUND AND DESIGN: Sorbic acid is a preservative that can induce cutaneous vasodilation characterized by erythema, urticaria, and stinging when applied topically to humans. Previous studies have suggested that prostaglandins may mediate the vasodilation, but the prostaglandin responsible has not been established. Recently, we have shown that cutaneous erythema similar ...
Lodge N J - - 1994
The use of cyclosporine A (CsA), a cyclic polypeptidic immunosuppressive agent, is associated with a number of cardiovascular problems. This study assessed the effects of CsA and its vehicle, cremophor EL (cremophor), on force development in isolated vascular tissue. CsA evoked a concentration-dependent increase in force (EC50 = 2.5 +/- ...
Hanazaki K - - 1994
BACKGROUND: Prostaglandins are widely known to have cytoprotective effects in a variety of conditions. Thromboxane A2 has the opposite effect of prostaglandins. In this study the effects of the thromboxane A2 receptor antagonist ONO 3708 on ischemia and subsequent reperfusion in the dog liver was evaluated. METHODS: Mongrel dogs weighing ...
Lambert A C - - 1994
o-Phenylphenol (OPP) and its sodium salt, sodium o-phenylphenate are broad spectrum fungicides and disinfectants with widespread usage. Both chemicals have been reported to induce cancer in the kidney and urinary bladder of Fischer 344 rats. Recently it has been proposed that the metabolic activation of OPP occurs via a two-step ...
Smith G C - - 1994
The purpose of this study was to determine which receptors mediate the dilator effects of prostaglandins (PGs) on the ductus arteriosus of the fetal rabbit. Isolated rings of the vessel from fetal New Zealand White rabbits were precontracted with indomethacin (1 microM) and potassium (25 mM) in 100 to 110 ...
Murphy E J - - 1994
A computer-controlled impactor was used to produce a severe spinal cord injury in the rat thoracic spinal cord. Cords were rapidly frozen in situ at 5, 15, 30, and 60 min and 6, 12, and 24 h postinjury. Control cords were noninjured cords from animals having undergone a laminectomy and ...
Lugea A - - 1994
BACKGROUND/AIMS: Surfactant phospholipids impede diffusion of acid through the gastric mucus, but their relevance in the defense of the duodenum against luminal acid is not known. METHODS: Duodenal resistance to acid was tested in anesthetized rats by instillation of HCl using a tube implanted in the proximal duodenum. The effects ...
Martinez J M - - 1994
Previous studies in bullfrogs have demonstrated the presence of leukotriene (LT)C4 binding sites in the brain. However, synthesis of eicosanoids by brain tissue has not been examined. Because prostaglandin (PG) synthesis differs in warm- and cold-acclimated bullfrog lung tissue, this study compared the synthesis of prostaglandins and leukotrienes in brains ...
Cooke R G - - 1994
Intrauterine administration of nordihydroguaiaretic acid (NDGA) will maintain luteal function in sheep and also suppress the release of both oxytocin and prostaglandin F2 alpha (PGF2 alpha) suggesting that 5-lipoxygenase products of arachidonic acid may be involved in ovine luteolysis. During luteolysis, uterine PGF2 alpha is considered to be the major ...
Graham J - - 1994
This study examines the effect of a 6 month dietary supplement of either gamma-linolenic acid (GLA) or eicosapentaenoic acid (EPA) on the synthesis of prostaglandins E2 and F2 alpha by the endometrium of women with regular menstrual cycles. Samples of endometrium, obtained pre- and post-treatment, were incubated in vitro for ...
Bakovic M - - 1994
The oxidation of ferulic acid by hydrogen peroxide catalyzed by prostaglandin H synthase follows a modified ping-pong irreversible mechanism, as is the case for classical peroxidases. The rate constant for the reaction of prostaglandin H synthase with hydrogen peroxide, determined from steady-state results, is (1.31 +/- 0.1) x 10(6) M-1 ...
Tran-Thi T A - - 1994
In this study, the capacity of hepatocytes to degrade prostaglandins diminished if the partial oxygen pressure dropped below 5%. This decrease was accompanied by an increased lactate/pyruvate ratio, a decrease in fatty acid oxidation and a drop in the ATP level. The degradation of exogenous adenosine increased with decreasing oxygen ...
Beckh K - - 1994
Prostaglandins have been postulated to act as mediators of intercellular communication between liver cell populations in the regulation of liver carbohydrate metabolism. Their role in the regulation of bile secretion is rather unclear. The action of prostaglandins on bile flow and bile acid secretion was studied in the in situ ...
Sarosiek J - - 1994
OBJECTIVES: Although the prostaglandin-mediated mucosal protection within the gastric compartment has been well established, its potential role in the maintenance of integrity of the esophageal mucosa in humans has not been explored due to the lack of appropriate methodology. METHODS: We have recently developed an esophageal perfusion catheter, equipped with ...
Slomiany B L - - 1994
1. The mechanism of sucralfate-induced gastric mucosal prostaglandin generation was investigated using mucosal cells labeled with [14C]choline and [3H]arachidonic acid. 2. In comparison to the controls, the cells maintained in the presence of sucralfate showed a concentration dependent increase in lysophosphatidylcholine (LPC) synthesis and PGE2 generation. The maximal effect was ...
Lehmann W D - - 1994
Investigations on the regio- and stereochemistry of the reactions of mammalian lipoxygenases and of prostaglandin H synthases are reviewed. The results and concepts are summarized as two reaction box models. The structures of all known (S)-type lipoxygenase products of long-chain fatty acids carrying an all-cis-1,4-diene structural element including mono-, di-, ...
Jen C J - - 1994
To investigate the regional variability in intrathoracic vascular prostaglandin (PG) synthesis, we obtained vessel segments from porcine coronary artery (COA), thoracic aorta (AT), common carotid artery (CRA), pulmonary artery (PA), pulmonary vein (PV), and inferior vena cava (IVC). Vascular production rates of 6-keto-PGF1 alpha (an indicator for PGI2), PGF2 alpha, ...
Ylikorkala O - - 1994
Primary menorrhagia, IUD side effects and endometriotic symptoms may be a result of excessive PG release in the reproductive organs. These conditions and symptoms can be prevented or markedly alleviated by a PG synthesis inhibitor, such as tolfenamic acid. This treatment, which is used only intermittently, has been well tolerated ...
Fujita T - - 1994
The effect of 13-hydroperoxyoctadecadienoic acid (13-HPODE) on the synthesis of prostaglandins (PGs) was examined in rabbit kidney medulla microsomes. Medulla microsomes were incubated with arachidonic acid in 0.1 M-Tris/HCl buffer (pH 8.0) containing reduced glutathione and hydroquinone and the PGE2, PGF2a and PGD2 formed were measured by high-pressure liquid chromatography ...
Godessart N - - 1994
Inhibition of the formation of pro-inflammatory eicosanoids such as leukotrienes and 12-hydroxyeicosatetraenoic acid by 15-hydroxyeicosatetraenoic acid (15-HETE) has been reported. Psoriatic dermis synthesizes reduced levels of 15-HETE and it has been postulated to play a role in the pathophysiology of this disease. Interleukin-1 stimulates the production of prostaglandin E2 in ...
Leikauf G D - - 1993
When inhaled, ozone reacts at the airway luminal surface with unsaturated fatty acids contained in the extracellular fluid and plasma membrane to form an aldehyde and hydroxyhydroperoxide. The resulting hydroxyhydroperoxide degrades in aqueous systems to yield a second aldehyde and hydrogen peroxide (H2O2). Previously, we demonstrated that ozone can augment ...
Hoffman D R - - 1993
Normal ovine pregnancy is associated with elevated levels of circulating vasodilator prostaglandins (PGs) and increases in PG production by uterine and systemic arteries. We hypothesized that the availability of fatty acid substrate may regulate PG production in vasculature from nonpregnant, pregnant and fetal sheep. In pregnant sheep, levels of arachidonic ...
Pasetto N - - 1993
The effect of interleukin-3 (IL-3) on prostaglandin E2 (PGE2) release by human fetal membranes at term gestation was evaluated. It was found that interleukin-3 stimulates in vitro prostaglandin E2 release by these gestational tissues, suggesting that interleukin-3 might be involved in the regulation of arachidonic acid metabolism in the fetal ...
Fletcher J R - - 1993
Eicosanoids were discovered as "prostaglandins" in the mid-1930s. The discovery that eicosanoids were ubiquitous in mammalian cells and that nonsteroidal anti-inflammatory drugs worked by inhibiting enzymes that synthesized these chemicals heralded their extensive investigation in all fields of biology. Precursor fatty acids (arachidonic acids) are stored in cell phospholipids, acted ...
Oliw E H - - 1993
Human spermatozoa are associated with arachidonate 15-lipoxygenase activity. This activity could be due to 15-lipoxygenase in small organelles (prostasomes), which are known to bind hydrophobically to germ cells. This possibility was assessed by separating prostasomes from human spermatozoa by differential centrifugation and purifying them by gel filtration (Sephadex G-200). Purified ...
Milićević N M - - 1993
The close topographical correlation between naphthol AS-D chloroacetate esterase-positive macrophages and prostaglandin synthase-rich macrophages in the thymus of normal and cyclosporin-treated rats was observed. It seems possible that chloroacetate esterase is an enzyme related to metabolism of arachidonic acid and/or production of its active metabolites.
Oliw E H - - 1993
Incubation of 5,8,11-[1-14C]eicosatrienoic acid with prostaglandin endoperoxide synthase of ram vesicular gland microsomes led to formation of a number of polar metabolites. Four major compounds were characterized by chemical and physical methods and found to be: (11R)-hydroxy-5,8,12-eicosatrienoic acid, 8,9,11-trihydroxy-5,12-eicosadienoic acid (two diastereoisomers), and 8,9-epoxy-11-hydroxy-5,12-eicosadienoic acid. On the basis of previous ...
Daret D - - 1993
We have investigated whether cellular metabolism of linoleic acid (18:2) can influence prostacyclin (PGI2) production by cultured rat aortic smooth muscle cells (SMC) and tissues. Incubation of rat SMC homogenates with [1-14C]18:2 results in the enzymatic synthesis of [14C]13-HODE (hydroxyoctadecadienoic acid) and to a lesser extent [14C]9-HODE as defined by ...
Grataroli R - - 1993
The purpose of this study was to investigate in rats the effects of three anthracyclines, pirarubicin, doxorubicin and epirubicin on gastric prostaglandin E2 (PGE2) metabolism and phospholipase A2 (PLA2, EC 3.1.1.4) activity. The level of the membrane precursor, arachidonic acid, and the stability of the membrane were investigated by analysis ...
Sakuma S - - 1993
The effect of a hydroperoxy adduct of linoleic acid, 13-hydroperoxyoctadecadienoic acid (13-HPODE), on 15-hydroxy prostaglandin dehydrogenase activity in rabbit kidney cortex was examined. 13-HPODE inhibited the 15-hydroxy prostaglandin dehydrogenase activity at concentrations ranging from 1 to 10 microM. The effect was concentration-dependent and the concentration required for 50% inhibition was ...
Amruthesh S C - - 1993
We have recently shown that brain slices are capable of metabolizing arachidonic acid by the epoxygenase pathway. The purpose of this study was to begin to determine the ability of individual brain cell types to form epoxygenase metabolites. We have examined the astrocyte epoxygenase pathway and have also confirmed metabolism ...
Diczfalusy U - - 1993
We have shown that rat liver peroxisomes can chain-shorten prostaglandins to dinor- and tetranor-metabolites. In a recent in vivo study we could demonstrate that peroxisomes are of major importance for chain-shortening of prostaglandin F2 alpha in humans (1991, Diczfalusy et al. J. Clin. Invest. 88:978-984). This was shown by identifying ...
Carroll M A - - 1993
The 5,6-epoxyeicosatrienoic acid (5,6-EET), a renal vasodilator metabolite of arachidonic acid via cytochrome P450 (P450) requires cyclooxygenase for expression of its vasoactivity as the responses are inhibited by indomethacin and other aspirin-like drugs. We now report on the metabolism of 5,6-EET by rabbit kidneys in order to characterize those metabolites ...
Mtabaji J P - - 1993
Spontaneously hypertensive rats (SHR) respond to angiotensin and norepinephrine with an exaggerated pressor response. We have investigated the possibility that increased vascular reactivity in SHR may be related to a reduced synthesis of prostaglandin E1 (PGE1) resulting from a defect in the release of its precursor, dihomo-gamma-linoleic acid (DGLA). Isolated ...
Lavoie J C - - 1993
Antioxidant properties of bisulfite are used to stabilize parenteral amino acid solutions. After reports of adverse reactions to dietary sulfites, we evaluated whether the infusion of bisulfite had biologic effects on human vascular tissue. Because an endothelial oxidative injury can affect mediators of vasoreactivity, vascular pressure and prostaglandin production were ...
Schilderman P A - - 1993
The dominant metabolic pathway of the presumably carcinogenic food antioxidant 2(3)-tert-butyl-4-hydroxyanisole (BHA) includes O-demethylation to 2-tert-butyl(1,4)hydroquinone (TBHQ) and subsequent peroxidation to 2-tert-butyl(1,4)paraquinone (TBQ). In order to determine the ability of TBHQ to induce the formation of oxygen radicals, electron spin resonance measurements were performed in presence and absence of peroxidases. ...
Won S J - - 1993
The pyrogenic response to supernatants from human blood monocytes stimulated with polyriboinosinic acid:polyribocytidylic acid (poly I:C) was characteristic of a response to endogenous pyrogen in that it was brief and monophasic, and was destroyed by heating the supernatants at 70 degrees C for 30 min. Pyrogen production was unimpaired when ...
Nevhutalu P A - - 1993
Schistosoma mansoni cercarial transformation and early stages of penetration can be correlated to specific eicosanoid products. Cercarial eicosanoids are suggested to play immunoregulatory roles during penetration. We examined production of cercarial eicosanoids by S. mansoni compared with that of the duck parasite Trichobilharzia ocellata after incubation with linoleate. Secretions were ...
Botha A - - 1993
Using radioimmunoassay, blood platelet aggregation studies and GC-MS the existence of prostaglandins in the endomycetalean yeast Dipodascopsis uninucleata was confirmed by our group. These findings triggered the search for similar eicosanoids in the rest of the Endomycetales. We commenced by scanning for the easily detectable precursors of eicosanoids, linoleic- and ...
Bioque G - - 1993
N-phenyllinoleamide (NPLA) has been detected as extraneous compound in adulterated cooking oils associated with a unique epidemic disease known as the Toxic Oil Syndrome (TOS). In this communication we report on the action of NPLA on the endogenous cyclooxygenase and lipoxygenase arachidonate metabolism. Results show that mouse peritoneal macrophages (MPM) ...
Korte K - - 1993
In decidual tissues of first trimester therapeutic abortions we have identified a large macrophage population that is stained by a specific antibody (Ki-M8). Also, we evaluated the capacity of decidual cells, obtained before and after labor, to synthesize prostanoids from radiolabeled arachidonic acid. Decidua collected after vaginal delivery produced significantly ...
Fukushima T - - 1993
With a simplified method of extracting and purifying prostaglandins, trace prostaglandins (nanogram order) were detected by gas chromatography-mass spectrometry. Arachidonic acid was metabolized to prostaglandin E2 (PGE2) by plerocercoids of Spirometra erinacei, the PGE2 was detected in the medium after incubation with arachidonic acid, and the role of albumin in ...
Greenfield S M - - 1992
In parallel studies, the effects of 5-aminosalicylic acid (5-ASA) and acetyl-5-aminosalicylic acid (acetyl-5-ASA) on peroxidation of red-cell membrane lipids and production of prostaglandins by peripheral blood mononuclear cells were assessed. 5-ASA at concentrations of 10(-5), 10(-4) and 10(-3) M significantly inhibited erythrocyte lipid peroxidation, measured as malondialdehyde production, by 20%, ...
DeGray J A - - 1992
We have analyzed the low temperature EPR spectra of the protein-derived tyrosyl radicals detected upon addition of arachidonic acid or 5-phenyl-4-pentenyl-1-hydroperoxide (PPHP) to prostaglandin H synthase. With either arachidonic acid or PPHP the initial radical detected is a doublet (peak-to-trough = 35 Gauss) that disappears rapidly and is replaced by ...
Roy A C - - 1992
Five homogenates of human sperm cells were separately incubated with [14C]arachidonic acid in the presence of reduced glutathione, L-tryptophan, and haematin as cofactors. The cyclooxygenase products of arachidonic acid metabolism were extracted, separated, and measured for their radioactivity. The rate of formation of prostaglandin (PG)D2, PGE2, PGF2 alpha, 6-keto PGF1 ...
De Meyer G R - - 1992
1. One of the major fatty acids in the arterial wall is linoleic acid. It has been shown that its 13-hydroxy metabolite (13-HODE) is generated in significant amounts by cultured endothelial cells. The aim of the present study was to investigate the relaxations to 13-HODE and its hydroperoxyprecursor (13-HPODE) and ...
Messina E J - - 1992
The aims of the present study were to determine the response of rat cremaster muscle first-order arterioles to hypoxia and the role of endothelium-derived prostaglandins in the response. Isolated arterioles were cannulated, pressurized to 65 mm Hg, and studied in a no-flow condition in a bath containing Krebs' bicarbonate solution, ...
Weber P S - - 1992
The stable adipogenic cell line TA1 was investigated as a potential in vitro system to examine effects of beta-adrenergic agonists on lipid metabolism at the cellular level. Initial experiments were conducted to establish whether dexamethasone, indomethacin, or both in combination induce rapid differentiation of TA1 preadipocytes to adipocytes. Based on ...
Grataroli R - - 1992
The effects of increased dietary n-3 polyunsaturated fatty acids on gastric mucosal lipid metabolism were studied in rats fed for 8 weeks with different combinations of fish and corn oils. Lipid composition, ex vivo prostaglandin E2 (PGE2) production and enzymatic activities involved in phospholipid metabolism and peroxisomal oxidative catabolism of ...
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