Search Results
Results 201 - 250 of 1137
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Brock T G - - 1999
The two cyclooxygenase isoforms, cyclooxygenase-1 and cyclooxygenase-2, both metabolize arachidonic acid to prostaglandin H2, which is subsequently processed by downstream enzymes to the various prostanoids. In the present study, we asked if the two isoforms differ in the profile of prostanoids that ultimately arise from their action on arachidonic acid. ...
Schäfer D - - 1999
The underlying mechanisms of bronchoconstriction in aspirin-intolerant asthmatics (AIAs) are still unknown, but the hypothesis of an altered metabolism of arachidonic acid is generally accepted. So far, no in vitro test for aspirin intolerance is available. The hypothesis that the profile of eicosanoid mediators is changed in AIA-even before aspirin ...
Hua X Y - - 1999
Substance P is an important neuromediator in spinal synaptic transmission, particularly in processing nociceptive afferent information. The effects of substance P are mediated by activation of the neurokinin 1 receptor. Evidence has suggested that excitatory amino acids such as glutamate, and prostaglandins including prostaglandin E2 are involved in the enhanced ...
Modéer T - - 1999
Benzydamine [1-benzyl-3-(3-dimethylamino)propoxy-1H-indazole] is a drug with analgesic, anesthetic, antimicrobial and anti-inflammatory activity. The purpose of the present study was to investigate the effect of benzydamine on prostaglandin production in human gingival fibroblasts. Benzydamine significantly reduced the basal production of both prostaglandin E2 (PGE2) and 6-keto-PGF1 alpha, the stable breakdown product ...
Kawai Y - - 1999
Nalpha-[3-(Hexadecanoyloxy)hexadecanoyl]-ornithine is a typical bacterial ornithine-containing lipid (OL). The configuration of the 3-hydroxy fatty acids in the OL was proved to be D by using HPLC with chiral column. For this analysis, Nalpha-(D or L)-[3-(hexadecanoyloxy)hexadecanoyl]-L-ornithine were synthesized and used as standards. The typical bacterial OL, as well as the synthesized ...
Moore S D - - 1999
OBJECTIVE: The purpose of this study was to identify the isoforms and splicing patterns of prostaglandin H synthase present in pregnant human lower-segment myometrium and determine whether there is differential expression of the isoforms or splice variants with respect to gestational age or parturition. STUDY DESIGN: Lower-segment myometrium was collected ...
Barzanti V - - 1999
The availability of the fatty acids which are precursors of prostaglandins is affected by dietary intake. We have studied, in particular, the effects of dietary intake of lipids with different amounts of precursor and derivative fatty acids on the synthesis of prostaglandin E2 (PGE2) in rat liver, kidney and lung. ...
Parchmann S - - 1998
The free radical oxidation of arachidonic acid is known to generate complex metabolites, termed isoprostanes, that share structural features of prostaglandins and exert potent receptor-mediated biological activities. In the present study, we show that alpha-linolenic acid can undergo a similar oxidation process, resulting in a series of isomeric dinor isoprostanes ...
Gao T - - 1998
Changes in the fatty acid composition of phospholipid and triglyceride fractions in Spirometra erinaceieuropaei plerocercoids were investigated after 0, 0.5, 1, 3, and 6 hr incubation at 10 C and 37 C with physiological saline containing 5 mM arachidonic acid and 10 mg/ml bovine serum albumin, pH 7.0. At 37 ...
Han Y - - 1998
Cord factor (trehalose 6,6'-dimycolate: TDM) is a well-known toxic glycolipid in Mycobacterium tuberculosis. We isolated various mycoloyl glycolipids from Nocardia asteroides 23,167 and related species which are closely related taxonomically to Mycobacterium. Since Nocardia is also an opportunistic pathogen co-infected with HIV, we examined in vivo granuloma formation and the ...
Ma H - - 1998
Peroxisome proliferation has been associated with carcinogenesis in the liver, and estrogen intake has been associated with increased risk of cancer in the hormone target tissues. Estrogen-induced peroxisome proliferation has been observed in an estrogen target tissue, the uropygial gland in the duck. To elucidate the molecular mechanism of this ...
Müller-Decker K - - 1998
A clinical study was performed to determine the effects of patch testing human skin with four industrially used surfactants on erythema formation, transepidermal water loss, and the contents in suction blister fluids of primary proinflammatory mediators including arachidonic acid, eicosanoids, and IL-1 alpha, which were analyzed by quantitative gas chromatography/negative ...
Ringbom T - - 1998
A hexane extract of Plantago major was investigated by bioactivity-directed fractionation, using an in vitro cyclooxygenase-2 (COX-2) catalyzed prostaglandin biosynthesis inhibition assay, and resulted in the isolation of ursolic acid (1). This triterpenoid showed a significant COX-2 inhibitory effect, directly on the enzyme activity, with an IC50 value of 130 ...
Fulton D - - 1998
The 5,6 epoxyeicosatrienoic acid (5,6-EET) exhibits a range of biological activities but the functional significance of this labile eicosanoid is unknown due, in part, to difficulties of quantitation in biological samples. We have developed a sensitive and specific method to measure 5,6-EET utilizing its selective capacity to form a lactone. ...
Michaelson L V - - 1998
Arachidonic acid (C20:4 Delta5,8,11,14) is a polyunsaturated fatty acid synthesized by the Delta5-fatty acid desaturation of di-homo-gamma-linolenic acid (C20:3 Delta8,11,14). In mammals, it is known to be a precursor of the prostaglandins and the leukotrienes but it is also accumulated by the filamentous fungus Mortierella alpina. We have isolated a ...
Kulmacz R J - - 1998
Prostanoids are a group of potent bioactive lipids produced by oxygenation of arachidonate or one of several related polyunsaturated fatty acids. Cellular prostaglandin biosynthesis is tightly regulated, with a large part of the control exerted at the level of cyclooxygenase catalysis by prostaglandin H synthase (PGHS). The two known isoforms ...
Matsumoto H - - 1998
Pretreatment of mice with lipopolysaccharide for 16 h enhanced the number of acetic acid-induced writhing reactions by 2 to 3-fold. In the peritoneal exudates at 10 min after acetic acid injection, 6-keto-prostaglandin F1alpha was detected as a major prostanoid, and this level increased by several-fold by the pretreatment with lipopolysaccharide. ...
Mikuni M - - 1998
OBJECTIVE: Our aim was to explain the effect of the nonspecific angiotensin II antagonist saralasin and the specific angiotensin II type-2 receptor antagonist PD123319 on ovulation. STUDY DESIGN: Saralasin, 1 micromol/L (n = 5), and PD123319 10 micromol/L (n = 6), were administered to in vitro perfused rat ovary. Prostaglandin ...
Dunstan C - - 1998
The new phenolic compound, 3,5-dihydroxy-4-methoxy phenethyl alcohol, named alphitol, and betulinic acid were from the bark of Alphitonia zizyphoides. The chemical structure of alphitol was determined by mass spectrometry in combination with one and two dimensional NMR, including HMBC. Both compounds inhibited prostaglandin biosynthesis in vitro, alphitol with an IC50 ...
Davidson J - - 1998
Phagocytosis by human monocytes is an important primary survival mechanism particularly during bacterial infection. However, the processes that control the events and mediators involved in the activation of monocytes and their impact on the phagocytosis of bacteria are poorly understood. The effect of bacterial endotoxin, interleukin-1 beta (IL-1 beta), fatty ...
Karageuzyan K G - - 1998
We studied how administration of trihydroxyoctadecadienoic acids obtained from the roots of the native Armenian plant Bryonia alba L. (0.05 mg/kg/day for 15 days. i.m.) restores the disordered lipid metabolism of alloxan-diabetic rats. Diabetes was accompanied by an increase in total non-esterified fatty acid content of blood together with decreases ...
Lees P - - 1998
Injections of mild irritants intradermally (carrageenan, zymosan and dextran) and intracaveally (carrageenan) in a tissue cage model of inflammation were used in studies of the pharmacodynamics and pharmacokinetics of tolfenamic acid administered intramuscularly in calves. Inhibition of serum thromboxane (TX)B2 and inflammatory exudate prostaglandin (PG)E2 were used as indicators of ...
Takeuchi Y - - 1998
The skin penetrative action of high purity cis-omega-12-octadecenoic acid (petroselinic acid, HP-PSA) on rat skin was compared with that of high purity cis-omega-9-octadecenoic acid (oleic acid, HP-OA), following treatment of rat intact skin surface with either 0.05 M HP-PSA or HP-OA in propylene glycol (PG), using Fourier transform/attenuated total reflection ...
Goodwin D C - - 1998
Tyrosyl radicals have been detected during turnover of prostaglandin endoperoxide H synthase (PGHS), and they are speculated to participate in cyclooxygenase catalysis. Spectroscopic approaches to elucidate the identity of the radicals have not been definitive, so we have attempted to trap the radical(s) with nitric oxide (NO). NO quenched the ...
Wentzel P - - 1998
Previous studies have suggested that the metabolism of arachidonic acid and radical oxygen species (ROS) are altered in diabetes and that these disturbances may induce severe embryonic dysmorphogenesis in diabetic pregnancy. We tested this hypothesis by studying whether an inhibition of the rate-limiting enzyme of prostaglandin biosynthesis, cyclooxygenase (COX), caused ...
Ohara M - - 1998
BACKGROUND: Gastric acid aspiration can result in acute lung injury. In this study, the authors determined whether alveolar macrophages express cyclooxygenase-2 as a source of inflammatory mediators after acid aspiration. METHODS: Seventy-five microliters of hydrochloric acid solution, pH 1.15, was instilled into one lung in mice. After exposure, alveolar macrophages ...
Koshkin V - - 1998
The pre-steady-state phase of the oxygenase reaction of prostaglandin endoperoxide synthase with cis,cis-eicosa-11, 14-dienoic acid has been studied using stopped flow techniques. Because some intermediate forms of prostaglandin endoperoxide synthase are spectrally indistinguishable, the enzyme and substrate transformations were monitored in parallel to simplify the interpretation of the kinetics. Over ...
Lamacka M - - 1998
Five strains of filamentous fungi belonging to the genera Mortierella and Cunninghamella were examined for the content of dihomo-gamma-linolenic, arachidonic, eicosapentaenoic acids and prostaglandins (type E2 and F2 alpha). Prostaglandins were detected using an ELISA method in mycelia of all tested strains (range 50-4800 ng g-1 of PGE2 and 6-30 ...
Brown J W - - 1998
The endocrine systems of vertebrates and higher invertebrates may have evolved functionally from as far back on the evolutionary scale as bacteria and early multicellular organisms and their biological communities, which have been shown to produce a variety of cyclic nucleotides, peptides, fatty acids, prostaglandins and sterols with endocrine-altering effects ...
Margalit A - - 1998
Intraperitoneal administration of urate crystals to mice reduced subsequent macrophage conversion of arachidonic acid (AA) to prostaglandins (PGs) and 12-hydroxyeicosatetraenoic acid for up to 6 h. In contrast, levels of 12-hydroxyheptadecatrienoic acid (12-HHT) were markedly elevated. This metabolic profile was previously observed in vitro when recombinant cyclooxygenase (COX) enzymes were ...
Reilly M P - - 1998
Arachidonic acid (AA) is an unsaturated fatty acid constituent of the phospholipid domain of cell membranes. It is subject to release via mobilization of phospholipases, particularly a cytoplasmic phospholipase A2. Thereafter, it may be metabolized by at least two cyclooxygenase (COX) isoforms to prostaglandins and related compounds, via lipoxygenases to ...
Downey B R - - 1998
Prostaglandins, products of arachidonic acid via the cyclooxygenase pathway, are essential to the porcine ovulatory process in that inhibition of their synthesis results in ovulation failure. Studies in the rat have shown that ovulation is also preceded by a rise in three ovarian hydroxyeicosatetraenoic acids, products of the lipoxygenase pathway, ...
Johnson R D - - 1998
OBJECTIVE: We tested the hypothesis that trophoblast produces 15-hydroxyeicosatetraenoic acid, and its level is elevated in trophoblast from preeclamptic women compared with normal. We also used selective enzymatic inhibitors to determine the relative contributions of 15-lipoxygenase and the two isozymes of prostaglandin H synthase to 15-hydroxyeicosatetraenoic acid levels. STUDY DESIGN: ...
Ryan C A - - 1998
Damage to leaves of several plant species by herbivores or by other mechanical wounding induces defense gene activation throughout the plants within hours. An 18-amino acid polypeptide, called systemin, has been isolated from tomato leaves that is a powerful inducer of over 15 defensive genes when supplied to the tomato ...
Hara T J - - 1998
A growing body of evidence indicates spatial patterning of molecular expression and physiological activities in the olfactory epithelium and primary afferent circuits of the vertebrate olfactory bulb. Because our previous studies indicate that olfactory receptors specific for amino acids and a bile acid, taurocholic acid, project to segregated coding centres ...
Colquhoun A - - 1998
Fatty acids have been shown to regulate the expression of mRNA for both lipogenic and glycolytic enzymes in rat liver. The role of fatty acids in the regulation of carnitine palmitoyltransferase (CPT) I and II activity in tumour cells was investigated. The polyunsaturated fatty acids, gamma-linolenic and arachidonic acid, caused ...
Bonventre J V - - 1997
Phospholipase A2 (PLA2) enzymes are critical regulators of prostaglandin and leukotriene synthesis and can directly modify the composition of cellular membranes. PLA2 enzymes release fatty acids and lysophospholipids, including the precursor of platelet-activating factor, PAF, from phospholipids. Free fatty acids, eicosanoids, lysophospholipids and PAF are potent regulators of inflammation, reproduction ...
Stepniakowski K T - - 1997
Evidence supports the hypothesis that elevated nonesterified fatty acids (NEFAs) in patients with insulin resistance, eg, obese hypertensive subjects, contribute to increased vascular alpha-adrenergic reactivity and tone by impairing endothelium-dependent vasodilation. To generate further support for this notion, we studied responses to endothelium-dependent and independent dilators under control (0.9% NaCl/heparin) ...
Anil K - - 1997
The mechanism of the hypolipidemic effect of n-3 fatty acids was studied using isolated rat hepatocytes maintained in culture. EPA and DHA caused a significant reduction in the incorporation of 3[H]-leucine into apoB associated with the VLDL produced by hepatocytes in culture when compared to that in presence of palmitic ...
Ali I - - 1997
Trophocytes from the disaggregated fat body of the cockroach (Periplaneta americana) respond to synthetic hypertrehalosemic hormone (HTH) by increasing the rate of trehalose synthesis. The cells give a similar response when incubated with stearic, oleic, linoleic, or arachidonic acid. A maximal increase in trehalose synthesis was obtained with 1-10 microM ...
Sharma S - - 1997
There are 3 main enzymatic pathways for synthesis of eicosanoids from arachidonic acid, however, some compounds are also formed non-enzymatically. Among the enzymatic pathways, cyclooxygenase (COX) also known as prostaglandin synthase (PGHS), generates endoperoxides (PGG/H). These are converted into prostaglandins (PGs) and thromboxanes (TXs). The second pathway involves lipooxygenase (LOX) ...
Koljak R - - 1997
A distant relative of catalase that is specialized for metabolism of a fatty acid hydroperoxide was identified. This heme peroxidase occurs in coral as part of a fusion protein, the other component of which is a lipoxygenase that forms the hydroperoxide substrate. The end product is an unstable epoxide (an ...
Yu M - - 1997
Because of its structural similarity to polyunsaturated fatty acids, anandamide could serve as substrate for enzymes such as lipoxygenases and cyclooxygenases, which metabolize polyunsaturated fatty acids to potent bioactive metabolites. Here the ability of recombinant human cyclooxygenase-1 (hCOX-1) and cyclooxygenase-2 (hCOX-2) to metabolize anandamide was studied. Baculovirus-expressed and -purified hCOX-2, ...
Soydan A S - - 1997
Human stomach tumours usually form more prostaglandins (PGs) than their associated normal mucosa/submucosa, but the mechanisms are not fully understood. The key enzymes are cytosolic phospholipase A2 (cPLA2, Mr 85,000) and the cyclo-oxygenases (COXs) which exist in constitutive (COX-1) and inducible forms (COX-2). In human stomach tumours and associated macroscopically ...
Gandawidjaja L - - 1997
The anatomic aspect of peritonitis describes the division of the abdominal cavity into the supracolic, infracolic and paracolic spaces, moreover the lesser sac and the cul-de-sac of the pelvis. Physiologically the peritoneum plays an important role in the passive exchange of fluid and absorption of particles. Endotoxin, which is elaborated ...
Swinney D C - - 1997
Prostaglandins are synthesized by prostaglandin H synthase (PGHS) 1 and 2. PGHS2 is regulated through inducible expression. We report here the regulation of PGHS1 activity by substrate-dependent cooperative activation. The cooperativity is characterized by a Hill coefficient of 1.29 +/- 0.06, a curved Eadie-Scatchard plot, and activation by low concentrations ...
Kumar K V - - 1997
Angiotensin-converting enzyme (ACE) is known to play an important role in the pathobiology of human essential hypertension. Similarly, cis-unsaturated fatty acids, prostaglandins, and free radicals are believed to play a role in the control of blood pressure. It was observed that all the cis-unsaturated fatty acids tested can inhibit ACE ...
Moreau R A - - 1997
Tetrahydroxybacteriohopane (1), a bacterial hopanoid, inhibited soybean 15-lipoxygenase with an IC50 of about 10 microM. After per-O-acetylation of 1 no inhibition of the 15-lipoxygenase was observed. Two other bacterial hopanoids, tetrahydroxybacteriohopane glucosamine (2) and tetrahydroxybacteriohopane ether (3), stimulated the activity of soybean 15-lipoxygenase. The activities of two other arachidonic acid-metabolizing ...
Murthy S - - 1997
This study investigated metabolic and biochemical consequences of colonic ischemia/reperfusion (I/R) in the rat and evaluated whether antioxidants prevent I/R-induced functional damage in the rat colon. The surgical preparation involved a 10 cm segment of the colon and occlusion of the superior mesenteric artery (SMA) to induce I/R. Arterial blood ...
Oliw E H - - 1997
Prostaglandin H synthase-1 of ram vesicular glands metabolises 5,8,11-eicosatrienoic (Mead) acid to 13R-hydroxy-5,8,11-eicosatrienoic and to 11R-hydroxy-5,8,12-eicosatrienoic in a 5:1 ratio. We wanted to determine the metabolism of this fatty acid by prostaglandin H synthase-2. Western blot showed that microsomes of sheep and rabbit placental cotyledons contained prostaglandin H synthase-2, while ...
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