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H Salari

Publications and source records attributed to H Salari.

At least 73 records · Page 4Linked to original sources

Gas chromatography-mass spectrometry of monohydroxyeicosatetraenoic acids as their methyl esters trimethylsilyl, allyldimethylsilyl and tert.-butyldimethylsilyl ethers.

The gas chromatographic and mass spectrometric properties of the monohydroxy acids 5-hydroxyeicosatetraenoic acid (5-HETE), 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-hydroxyeicosatetraenoic acid (15-HETE) as their methyl ester trimethylsilyl, methyl ester allyldimethylsilyl and methyl ester tert.-butyldimethylsilyl ethers were investigated. The gas chromatographic properties of the trimethylsilyl and tert.-butyldimethylsilyl derivatives were found to be excellent while the allyldimethylsilyl derivative required a well deactivated column. The mass spectra of these silyl derivatives with the exception for 12-HETE did not exhibit particularly intense ions in the upper mass region. A quantitative analysis by selected-ion monitoring of the most intense ion in the upper mass region of respective mass spectrum demonstrated that a detection limit in the low picogram range could only be obtained for 12-HETE. Since the mass spectra indicated that the double bonds exerted a strong influence on the fragmentation pattern, the trimethylsilyl, allyldimethylsilyl and tert.-butyldimethylsilyl ethers of the methyl esters of the reduced analogues of the monohydroxy acids were prepared. The saturation of the double bonds completely altered the fragmentation patterns and very intense ions carrying a high percentage of the total ion abundance were found in all of the mass spectra. The developed technique was utilized for measurements of 5-HETE in lung tissue samples from patients with lung cancer.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

Grain-dust extract induced direct release of mediators from human lung tissue.

To explore the mechanisms of grain dust-induced acute bronchoconstriction, extracts of grain dust were incubated with chopped human lung fragments. The supernatants of the incubation media were examined for the presence of leukotrienes and histamine with high-performance liquid chromatographic techniques. Human lung fragments responded to the extract of grain dust by releasing histamine in a dose-dependent manner. Moreover, leukotrienes (B4, D4, and E4 were also found to be released. The action of grain dust appeared to be independent of the complement pathway or cell cytotoxicity since the lung tissue released the chemical mediators in the absence of plasma and responded to further reaction with compound 48/80 after interaction with grain dust. These data demonstrate that grain-dust extract may induce the release of mediators of anaphylaxis by a nonimmunologic process. This may explain the occurrence of acute bronchoconstriction in some of the grain workers.

Allergens↗

Copper(II)(3,5-diisopropylsalicylate)2 accelerates recovery of B and T cell reactivity following irradiation.

Copper(II)(3,5-diisopropylsalicylate)2 (Cu-DIPS), administered subcutaneously to mice at 80 mg/kg body weight, had marked radioprotective activity. Given 3 h before exposure to 8.0 Gy (800 rad) irradiation, Cu-DIPS increased the 42-day survival from 40% to 86%. Seven days after exposure to 8.0 Gy, there were severe reductions in spleen weight (73%) and cellularity (98%) in both Cu-DIPS- and vehicle-treated mice. Viable spleen cells collected 7 days after irradiation were totally unresponsive to mitogenic or antigenic stimulation regardless of Cu-DIPS or vehicle treatment, suggesting that Cu-DIPS did not prevent radiation-induced damage to mature lymphocytes. At 14 days, when Cu-DIPS-treated mice started to show improved survival over vehicle-treated mice, spleen weights and cellularity were 2.5- and 3.5-fold higher, respectively, in Cu-DIPS-treated mice. Treatment with Cu-DIPS not only enhanced splenic repopulation, but also accelerated the reappearance of both B and T cell reactivities. Spleen cell responsiveness to the B cell mitogen, lipopolysaccharide (LPS), and the T cell mitogen, concanavalin A (Con A), regenerated significantly faster in Cu-DIPS-treated mice. Cu-DIPS also significantly accelerated the regeneration of T-dependent antibody induction. Based on these assays of immunocompetence, Cu-DIPS-treated mice had, on average, a seven-fold greater capacity to respond to immune stimulation than vehicle-treated mice 24 days after irradiation.

Animals↗

Plasma histamine after methacholine, allergen, and aspirin challenges.

Plasma histamine levels were measured by radio-enzymatic technique in seven patients following 10 challenges: five methacholine challenge tests, four antigen inhalation challenge tests, and one oral aspirin challenge test. Baseline plasma histamine was the same in all patients except in the aspirin-challenged patient, who had a higher baseline histamine level. There was no statistical change in the level of histamine throughout the test in either the methacholine-challenged or the antigen-challenged patients, whereas there was a marked increase in histamine levels in the aspirin challenged patient. A possible explanation is that methacholine and antigen are inhaled and therefore have primarily local effects on the lung, whereas oral aspirin has a systemic effect with consequently systemic changes in histamine which are detectable as changes in plasma level.

Adult↗

Release of leukotrienes and histamine by the isolated anaphylactic heart.

The purpose of this study was to demonstrate the ability of heart tissue to release the mediators of anaphylaxis after antigenic challenges. Guinea pigs were sensitized with ovalbumin. Hearts were excised, perfused in a langendorff apparatus, and challenged with a bolus injection of ovalbumin. Analysis of the perfusates demonstrated the presence of histamine as determined by radioenzymatic assay. Histamine release was observed to be maximum after 2 min (8 +/- 1 nmol) of perfusion, then decreased to baseline level. The heart also released LTB4, LTC4, LTD4, and LTE4 as determined by high performance liquid chromatography and bioassays. The release of LTC4 occurred rapidly, reaching maximum after 2 min (4.2 +/- 1 pmol) and then returned to baseline level. Although the release of LTD4 paralleled the release of LTC4, it reached a maximum after 5 min (7.7 +/- 2 pmol). LTE4 was detected after 10 min and was undetectable after 15 min. Maximum release of LTB4 was observed after 5-10 min (15 +/- 3 pmol) and was no longer detectable after 15 min. These results indicate that the isolated sensitized heart undergoing antigenic challenge releases leukotrienes and histamine suggesting the cardiac anaphylaxis might occur by the locally released mediators.

Anaphylaxis↗

A comparative study on the release of leukotrienes and histamine by guinea pig lung and trachea after challenge with antigen or stimulation with ionophore A23187 or melittin.

The release of leukotrienes and histamine from guinea pig lung and trachea after immunological and nonimmunological stimulation were compared. Antigen, ionophore A23187 and melittin caused the release of leukotriene (LT)B4, LTC4, LTD4 and LTE4 from lung and trachea as determined by reverse-phase high performance liquid chromatography (RP-HPLC) and bioassay. The release of LTB4 by lung and trachea was maximum after 5 min of ionophore stimulation (128 +/- 40 and 142 +/- 29 pmol/g tissue, respectively). Lung, but not trachea, also released the 20-OH-LTB4 and 20-COOH-LTB4. The release of LTC4 by lung tissues was maximum after 5 min, whereas maximal tracheal responses occurred at 10 min (27 +/- 11 and 9 +/- 3.5 pmol/g tissue, respectively). Maximal release of LTD4 by lung and trachea respectively occurred after 10 and 15 min (103 +/- 21 and 20 +/- 6 pmol/g tissue, respectively). The release of LTD4 in response to ionophore by both tissues decreased after 15 min, whereas the release of LTE4 continued to increase. Release of leukotrienes from melittin stimulated lung was 2-3-fold less than in ionophore stimulation. In contrast, tracheal responses to melittin and ionophore for the release of LTB4 were equivalent, whereas release of peptidoleukotrienes in response to melittin was approximately 50% that resulting from ionophore. Antigen challenge was the least potent stimulus for LTB4 release in both tissues, whereas it was at least as potent as melittin for the release of peptidoleukotrienes. The release of histamine by lung tissue was approximately 2-3-fold greater than by trachea (7 +/- 1 and 2 +/- 0.5 nmol/g tissue, respectively) after 5 min of stimulation with either ionophore, melittin or antigen. These data demonstrate that lung tissues and trachea respond to immunologic stimulations by releasing the mediators of inflammation and immediate hypersensitivity. The lung releases peptidoleukotrienes and histamine 2-5-fold greater than the trachea, whereas the release of LTB4 in both tissues are approximately equal.

Animals↗

Solid-phase extraction and reversed-phase high-performance liquid chromatographic technique for isolation and estimation of platelet activating factor in plasma.

A solid-phase extraction technique for the isolation of platelet activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC)] from biological matrices was developed. Amberlite XAD-2 was effective in retaining different molecular species of AGEPC from plasma and incubation media. The recovery of the three molecular species (C14-, C16-, and C18-AGEPC) was greater than 95%. XAD-2 also removed large amounts of plasma impurities, giving a cleaner high-performance liquid chromatographic (HPLC) profile. AGEPC in plasma or incubation media was not significantly removed by passage of the sample through a column packed with ODS-silica. A reversed-phase HPLC technique for separation and estimation of different species of AGEPC was developed. Resolution of C14-, C16- and C18-AGEPC was accomplished on a Hamilton PRP-1 resin column using an aqueous acetonitrile gradient containing 1 mM methanesulphonic acid. The detection limit was of the order of 50 ng of AGEPC at 210 nm. The AGEPC purified by the technique described retained its biological activity as determined by its ability to release endogenous serotonin from rabbit platelets.

Chromatography, High Pressure Liquid↗

Comparative study of solid phase extraction techniques for isolation of leukotrienes from plasma.

We have compared five commercially available absorbent materials (i.e. C18 Sep-Pak, C18 J.T. Baker, Amberlites XAD-7, XAD-2 and XAD-4) for their applicability as effective tools for extraction of leukotrienes from plasma samples. Leukotriene C4 (LTC4) and B4 (LTB4) were selected as representatives of peptidic and non-peptidic leukotrienes, respectively. These leukotrienes were added to 1 ml of plasma and passed through columns containing the above described adsorbent materials. The recovery was determined for each material using different combinations of solvents. XAD-4 gave the highest recovery for LTB4 (90%), whereas XAD-4 and XAD-2 gave identical recoveries for LTC4 (90%) when an eluting solvent mixture of pyridine-water--dimethylformamide (50:45:5) was used. The efficiency of the other three solid adsorbent materials for leukotriene extraction were in order of decreasing magnitude, C18 J.T. Baker greater than XAD-7 greater than C18 Sep-Pak. XAD-7 was shown to be more efficient for LTB4 than for LTC4, whereas the octadecylsilane C18 materials gave approximately similar recoveries for both of the leukotrienes. In addition to very good extraction properties of XAD-4 and XAD-2 as compared to octadecylsilane silica, these solid adsorbent materials retained less plasma impurities than the C18 materials, giving cleaner chromatograms for leukotrienes extracted from plasma. Therefore, XAD-4 or XAD-2 are the best overall choice for extraction of leukotrienes from plasma for reversed-phase high-performance liquid chromatographic analysis.

Chromatography, High Pressure Liquid↗

Studies on the biosynthesis of leukotrienes in guinea pig lung in vitro by use of high-performance liquid chromatography.

The biosynthesis of leukotrienes (LTs) and 5-hydroxy-6,8,-11,14(E,Z,Z,Z)-eicosatetraenoic acid (5-HETE) in perfused guinea pig lung was studied by reversed phase-high-performance liquid chromatography (RP-HPLC). Perfusion of lungs with a 20 microM solution of ionophore A23187 for 25 minutes induced a sustained release of 5S-hydroxy-6R-S-cysteinylglycyl-7,9,11,14-(E,E,Z,Z)-eicosatetraenoic acid (LTD4) and 5S,12R-dihydroxy-6,8,10,14(Z,E,E,Z)-eicosatetraenoic acid (LTB4). The perfusion of 60 microM of arachidonic acid together with the ionophore only slightly increased the synthesis of LTD4 and LTB4 in comparison with the effect of the ionophore alone but markedly stimulated the release of 5-HETE that was not detectable under other experimental conditions. Immunologic challenge of the lung by continuous perfusion of ovalbumin to previously sensitized guinea pigs induced the release of 50 to 150 pM of LTB4 and 15 to 50 pM of LTD4 during a 25-minute period. Antigen was a less potent stimulus than the ionophore that caused the release of 500 to 900 pM of LTB4 and 100 to 250 pM of LTD4 during 25-minutes of perfusion. None of the above-mentioned metabolites were detected when lungs were perfused with arachidonic acid alone, indicating that the synthesis of 5-lipoxygenase products required activation of the lung. In addition to 5-lipoxygenase products, the cyclooxygenase products 12-hydroxy-5,8,10-(Z,E,E)-heptadecatrienoic acid and 12-keto-5,8,10-(Z,E,E)-heptadecatrienoic acid were analyzed by RP-HPLC in guinea pig lung perfusates. HPLC analysis provided quantitative data on the release of several arachidonic acid metabolites by lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Immunological and non-immunological release of leukotrienes and histamine from human nasal polyps.

Nasal polyps were obtained from 22 patients undergoing polyp surgery. They were chopped into fragments of approximately 2 mm2, washed free of blood, and passively sensitized with serum from timothy allergen sensitive patients (RAST 30-40%), then, challenged with timothy allergen. Analysis of the incubation medium after a 30 min challenge as assessed by reversed phase high performance liquid chromatography and bioassay revealed the presence of leukotriene (LT) LTB4, LTC4, LTD4 and LTE4 (29 +/- 9, 6.6 +/- 3, 62 +/- 13 & 86 +/- 23 pmol/g tissue wet weight, respectively). The human nasal polyps also released histamine which reached a maximum after approximately 5 min (2.8 +/- 1.28 nmol/g tissue), as measured by radioenzymatic assay. A similar profile of leukotrienes and histamine release was observed when the nasal polyps were stimulated with ionophore A23187. However, the ionophore stimulated release was greater than that observed for the antigen challenge. When human polyps were stimulated with a mixture of the ionophore and arachidonic acid, all the above products as well as 5-hydroxy-eicosatetraenoic acid (5-HETE), 12-HETE, and 15-HETE were detected in the medium. These data, taken together, demonstrate that human nasal polyps are able to release significant amounts of leukotrienes and histamine upon both immunological and non-immunological stimulations and that these responses might significantly contribute to the symptoms of allergic rhinitis.

Allergens↗

Immunological and non-immunological release of leukotrienes and histamine by guinea-pig heart.

Fragments of sensitized guinea-pig heart (1 g wet weight) were incubated with 5 micrograms/ml of antigen for up to 30 min, and the incubation media were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC) for the presence of leukotrienes LTB4, LTC4, LTD4 and LTE4. Maximum release of LTB4, LTC4 and LTD4 was observed after 15 min (32.8 +/- 4, 8 +/- 2 and 9.5 +/- 2.5 pmol/g tissue wet weight, respectively, mean +/- SEM). At the same time, histamine was also released, reaching a maximum at 5 min (290 +/- 63 pmol/g tissue) as determined by radioenzymatic assay. Similarly, the non-sensitized guinea-pig heart stimulated with the ionophore A23187 (4 microM) released LTB4, LTC4, LTD4 and LTE4, as well as the 5-hydroxy-eicosatetraenoic acid (5-HETE), 12-HETE, and 15-HETE as determined by RP-HPLC. The release of LTB4, LTC4 and LTD4 was at a maximum after 10-15 min of stimulation (63 +/- 8.4, 10.7 +/- 2 and 17.5 +/- 4 pmol/g tissue). The ionophore also stimulated the release of histamine in heart tissue, with a peak maximum after 5 min (325 +/- 77 pmol/g tissue). These data demonstrate that heart as well as pulmonary tissues release significant amounts of leukotrienes and histamine during immunological or non-immunological challenges.

Animals↗

Studies on the release of leukotrienes and histamine by human lung parenchymal and bronchial fragments upon immunologic and nonimmunologic stimulation. Effects of nordihydroguaiaretic acid, aspirin, and sodium cromoglycate.

Fragments of human lung parenchyma or bronchi were studied by high performance liquid chromatography, gas chromatography-mass spectrometry, and bioassay for the biosynthesis of 5-lipoxygenase metabolites of arachidonic acid, and by radioenzymatic assay for the release of histamine, upon immunologic and nonimmunologic stimulation. Human lung parenchyma were passively sensitized with serum from timothy-positive allergic patients (radioallergosorbent test, 30-40%) and challenged with 0.5 microgram/ml of timothy allergen. Analysis of the incubation media showed the presence of LTB4, LTC4, LTD4, LTE4, and histamine. Maximum release of LTB4 and LTD4 was observed after 15 min of challenge (92.8 +/- 21, and 67.8 +/- 14 pmol/g tissue wet weight, respectively; mean +/- SEM) whereas maximum release of LTC4 was observed after 5 min of challenge (25 +/- 7.1 pmol). In parallel to leukotriene formation, histamine was released rapidly and reached a maximum after approximately 15 min of challenge (2.85 +/- 0.76 nmol/g tissue). When fragments of human lung parenchyma were stimulated with ionophore A23187 (4 microM), we observed a profile of leukotriene and histamine release similar to that seen in response to the allergen. Ionophore A23187 stimulated the release of two- to fivefold greater amounts of leukotrienes and histamine than did the allergen. Release of LTC4 and histamine was maximal after 5 min of stimulation (83 +/- 22.2 and 5.2 +/- 0.95 nmol/g tissue, respectively), whereas LTB4 and LTD4 release reached a maximum after 15 min (438 +/- 66.6 and 205 +/- 68 nmol/g tissue, respectively). In addition, human lung parenchyma metabolized LTB4 into omega-OH-LTB4 and omega-COOH-LTB4. This tissue also released 5-hydroxy-eicosatetraenoic acid (5-Hete), 12-Hete, and 15-Hete. Fragments of human lung bronchi also released a similar profile of leukotrienes (except LTC4) and histamine when challenged with the allergen or ionophore A23187. Maximum release of LTB4 and LTD4 by allergen or ionophore stimulation was observed after approximately 15 min (40 +/- 7.5 and 21 +/- 8 pmol/g tissue, respectively, upon allergen challenge; 100 +/- 13 and 47 +/- 10.6 pmol/g tissue, respectively, upon ionophore stimulation). The maximum release of histamine by bronchi was observed after approximately 15 min of allergen challenge and 5 min of ionophore stimulation (2.25 +/- 0.65 and 3.15 +/- 0.9 nmol/g tissue, respectively). The release of leukotrienes but not of histamine by human lung parenchyma upon both allergen and ionophore challenge was inhibited by nordihydroguaiaretic acid (NDGA) (ID50, 2 X 10(-6)M).(ABSTRACT TRUNCATED AT 400 WORDS)

Adjuvants, Immunologic↗

Characterization of effect of N-formyl-methionyl-leucyl-phenylalanine on leukotriene synthesis in human polymorphonuclear leukocytes.

Human polymorphonuclear leukocytes (PMNLs) were exposed to N-formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe) in the presence or absence of exogenous arachidonic acid. Analysis of incubation mixtures by high-performance liquid chromatography showed that f-Met-Leu-Phe stimulated the synthesis of 5-hydroxy-eicosatetraenoic acid (HETE) and of leukotriene B4 (LTB4) which was rapidly metabolized into 20-OH-LTB4 and 20-COOH-LTB4. The stimulatory effect of f-Met-Leu-Phe was dose and time dependent. The tripeptide showed maximum stimulatory activity at the concentration of 1 microM and after 20-30 min of incubation. Addition of arachidonic acid to the f-Met-Leu-Phe-stimulated PMNLs resulted in an increase in the synthesis of LTB4 and 5-HETE. Pretreatment of the PMNLs with cytochalasin B strongly potentiated (up to six-fold) the stimulatory effect of f-Met-Leu-Phe on 5-lipoxygenase product synthesis, whereas cytochalasin B alone or with arachidonic acid had no significant effect. The tripeptide did not increase the synthesis of platelet-derived 12-HETE, and 12-hydroxyheptadecatrienoic acid, or of PMNL-derived 15-HETE, suggesting that its action was selective for PMNL 5-lipoxygenase. The present data indicate that f-Met-Leu-Phe causes the release of arachidonic acid from cellular lipids and activates the 5-lipoxygenase.

Arachidonic Acid↗

Correlation between the myotropic activity of leukotriene A4 on guinea-pig lung, trachea and ileum and its biotransformation in situ.

Leukotrienes A4 and D4 displayed equivalent myotropic activity on guinea pig lung parenchyma strips. However, on the trachea, the activity of LTD4 was much higher than that of LTA4. The potencies of these two leukotrienes were also different on strips of longitudinal muscles of the ileum where LTD4 was very active whereas LTA4 was inactive. Since the activities of both leukotrienes were blocked by FPL-55712, our results suggested that the transformation of LTA4 by the smooth muscle preparations was a prerequisite to its biological activity. LTA4 was then incubated for 10 min with homogenates of guinea pig lung parenchyma, trachea and longitudinal muscles of ileum, and the metabolites were analysed by bioassay using strips of guinea pig ileum and lung parenchyma in a cascade superfusion system and also by reversed phase high performance liquid chromatography (RP-HPLC). Homogenates of lung parenchyma rapidly transformed LTA4 to LTB4, LTC4, LTD4 and LTE4. Incubation of LTA4 with homogenates of trachea or of the longitudinal muscles of ileum showed the formation of LTB4 and its isomers but no significant amount of peptido-leukotrienes were detected. These findings reveal that LTA4 undergoes distinctly different metabolic transformations in these tissues which correspond to the biological activities of the products recovered. These results strongly suggest that the myotropic activity and potency of LTA4 is related to the tissue levels of enzymes which catalyse its biotransformation.

Animals↗

Metabolism of leukotrienes by adult and fetal human lungs.

The metabolism of leukotriene (LT) A4, B4, C4, D4, and E4 was studied using both bioassay and reversed phase high performance liquid chromatography (RP-HPLC) methods. The incubation of 20,000 g supernatants of homogenates of human adult lung with LTA4 and LTC4 for various periods of time produced substances of higher biologic activity than the controls (without incubation) when measured on strips of guinea pig lung parenchyma and ileum. RP-HPLC analyses of the incubation media revealed the formation of LTB4, LTC4, LTD4, and LTE4 from LTA4 and the formation of LTD4 and LTE4 from LTC4. LTD4 was converted to LTE4 whereas LTB4 and LTE4 were not catabolized to an appreciable extent during a 2-h incubation period. Supernatants (20,000 g) of human fetal lung homogenates also contain the enzymatic activities to transform LTC4 into LTD4 and LTE4; however, LTA4 was mainly converted to LTB4 and to products of the nonenzymatic hydrolysis of LTA4 such as the delta 6-trans-LTB4, delta 6 -trans-12-epi-LTB4 and the 5,6-dihyroxyeicosatetraenoic acids; much smaller quantities of the peptidoleukotrienes were formed than in adult lung homogenates.

Adult↗

Stimulation of lipoxygenase product synthesis in human leukocytes and platelets by melittin.

The effects of melittin on the synthesis of lipoxygenase metabolites of arachidonic acid in human leukocytes and platelets were studied using high performance liquid chromatography. Melittin was found to stimulate strongly the formation of leukotrienes and hydroxy-eicosatetraenoic acids (HETEs) in a concentration-dependent fashion. The metabolites detected were LTB4, omega-OH-LTB4, omega-COOH-LTB4, LTC4, 5-HETE, 12-HETE, 15-HETE, 5S,12S-DiHETE, and 5S,15S-DiHETE. These results suggest that the action of melittin on the formation of arachidonic acid metabolites might be involved in its ability to release endogenous substrates required for the synthesis of 5-, 15-, and 12-lipoxygenase products in leukocytes and platelets, respectively.

Arachidonic Acid↗

Activation of prostacyclin synthesis in cultured aortic smooth muscle cells by 'diuretic-antihypertensive' drugs.

In cultured smooth muscle cells of rat aorta, four diuretic agents, furosemide, bumetanide, cicletanide and piretanide (all at 10(-6)-10(-5) M), significantly enhanced the transformation of exogenously added arachidonic acid (AA) to prostacyclin. Studies with cultured smooth muscle cells and human leukocytes revealed that these same agents failed to inhibit lipoxygenase pathways. Taken together, these results indicate that the diuretic properties of these agents might be associated with a general activation of the AA cascade.

Animals↗