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At least 775 records · Page 43Linked to original sources

PubMed1984

High-performance liquid chromatographic analysis of the semisynthetic epipodophyllotoxins teniposide and etoposide using electrochemical detection.

A high-performance liquid chromatographic (HPLC) assay was developed for the quantitation of two structurally similar and highly active anticancer drugs, etoposide (I) and teniposide (II), and their potential metabolites (hydroxy acid, picrolactone, and aglycone). The assay utilizes electrochemical detection, which imparts specificity and sensitivity sufficient to detect greater than or equal to 20 ng/mL in plasma, urine, and CSF. The mean assay coefficients of variation were 5.1 and 8.1% for teniposide (10 micrograms/mL) and etoposide (5 micrograms/mL), respectively. The extraction efficiencies were 86% for etoposide, 70% for its hydroxy acid metabolite, 66% for teniposide, and 54% for the hydroxy acid of teniposide. The correlation coefficient of the multilevel standard curve was greater than or equal to 0.995 over the concentration range of 0.05-50 micrograms/mL for the parent drugs and metabolites extracted from plasma. This method has been used to determine the concentrations of the parent drugs and their metabolites in the plasma, urine, and CSF of patients with cancer.

Body Fluids↗

PubMed1989

Polar lipids and fatty acids of Pseudomonas cepacia.

The polar lipids and fatty acids produced by the reference strains for seven different O serogroups of Pseudomonas cepacia have been identified. Similar results were obtained for all strains. Contrary to a previous report, the only significant phospholipids in this species are phosphatidylethanolamine and bis(phosphatidyl)glycerol, which contributed 57-83% and 17-43%, respectively, of the total lipid phosphorus. The former lipid was found as two chromatographically distinct fractions. In the less polar fraction and in bis(phosphatidyl)glycerol, the major fatty acids were hexadecanoic acid, cis-9,10-methylenehexadecanoic acid, cis-octadec-11-enoic acid, and cis-11,12-methyleneoctadecanoic acid. In the more polar fraction of phosphatidylethanolamine, the fatty acid in one position is a 2-hydroxy acid, mainly 2-hydroxyhexadecenoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecenoic acid, or 2-hydroxymethyleneoctadecanoic acid. Compared with other phospholipids, this fraction of phosphatidylethanolamine was depleted in cis-9,10-methylenehexadecanoic acid. Each strain also produced two ornithine amide lipids. In the major lipid, 3-hydroxyhexadecanoic acid was amide-bound to the alpha-amino group and was itself probably esterified by a 2-hydroxy acid, mainly 2-hydroxyoctadecenoic acid or the derived cyclopropane acid. In the minor ornithine amide lipid, the ester-bound acids were mainly methyleneoctadecanoic acid and hexadecanoic acid. The unusual lipid profiles of P. cepacia are of chemotaxonomic interest.

Chromatography, Thin Layer↗

PubMed2006

Characterization of anomalous flow and phase behavior in a Langmuir monolayer of 2-hydroxy-tetracosanoic acid.

Langmuir monolayers of long-chain fatty acids display a wide range of interesting flow and phase behaviors, but the correlation between these behaviors varies. In this paper, we report two interesting behaviors in a Langmuir monolayer of 2-hydroxy-tetracosanoic acid: phase coexistence between the L(2h) and L(2)' phases over a large pressure range and a peak in the viscosity and elastic modulus of the material as a function of pressure. The two behaviors are confirmed over a range of temperatures for which the location of the undistorted lattice appears to vary relative to the range of coexistence for the two phases. Evidence for a correlation between the phase behavior and the peak in the mechanical properties is presented.

Journal Article↗

PubMed1966

Appearance of 5-hydroxytryptamine and an unidentified pharmacologically active lipid acid in effluent from perfused cerebral ventricles.

1. In cats anaesthetized with intraperitoneal pentobarbitone sodium, three regions of the cerebral ventricles, the third ventricle, the inferior or the anterior horn, were perfused with artificial c.s.f. and the effluent was tested on the fundus strip of the rat's stomach.2. Effluent from all three regions contracted the fundus strip. The contractions were due to at least two substances as revealed by treatment of the strip with 2-bromolysergic acid diethylamide (BOL). The contractions that were sensitive to BOL are attributed to 5-hydroxytryptamine (5-HT) whereas the BOL resistant contractions appear to be due to an unknown hydroxy acid related to irin or the prostaglandins.3. The contractions produced by effluent collected from the third ventricle were due wholly or mainly to 5-HT, those from the inferior horn to the unknown hydroxy acid, and those from the anterior horn to both substances in varying proportions. In addition, some samples of effluent from the third ventricle seemed to contain catecholamines as well.4. The 5-HT in the effluent from the third ventricle is thought to be derived from the hypothalamus. The amounts assayed in 1 ml. effluent-the volume collected during 10 or 20 min perfusion-varied between 0.4 and 12 ng 5-HT. Output of 5-HT was initially high, then usually decreased but sometimes increased again during prolonged perfusion when temperature began to rise as anaesthesia lightened or when additional pentobarbitone sodium was given intravenously.5. When perfusion of the third ventricle was continued after death the 5-HT content in the effluent increased 3 to 24-fold during the first hour and then gradually declined. This post mortem rise in 5-HT output suggests an abnormal state of release of 5-HT from the hypothalamus. The theory is discussed that the same may happen in certain cases of brain injury and that the abnormal release of 5-HT would explain the pyrexia and shivering seen in such cases.6. The intraperitoneal injection of 5-hydroxytryptophan greatly increased the output of 5-HT in the effluent from the perfused third ventricle but only when this precursor of 5-HT was injected in large doses which caused respiratory arrest thus necessitating artificial ventilation. Upon the injection of 150 mg/kg the output of 5-HT rose to 90 ng/ml. and a further rise to 180 ng/ml. occurred when perfusion was continued after death.7. It was not possible to establish a relation between the presence of the hydroxy acid in the effluent from the inferior horn and neuronal activity.8. The 5-HT detected in the effluent from the anterior horn is assumed to have been released from the caudate nucleus.

5-Hydroxytryptophan↗

PubMed1989

Uncoupling of the cytochrome P-450cam monooxygenase reaction by a single mutation, threonine-252 to alanine or valine: possible role of the hydroxy amino acid in oxygen activation.

Site-directed mutants of cytochrome P-450cam (the cytochrome P-450 that acts as the terminal monooxygenase in the d-camphor monooxygenase system), in which threonine-252 had been changed to alanine, valine, or serine, were employed to study the role of the hydroxy amino acid in the monooxygenase reaction. The mutant enzymes were expressed in Escherichia coli and were purified by a conventional method. All the mutant enzymes in the presence of d-camphor exhibited optical absorption spectra almost indistinguishable from those of the wild-type enzyme in their ferric, ferrous, oxygenated, and carbon monoxide ferrous forms. In a reconstituted system with putidaredoxin and its reductase, the alanine enzyme consumed O2 at a rate (1100 per min per heme) comparable to that of the wild-type enzyme (1330 per min per heme), whereas the amount of exo-5-hydroxycamphor formed was less than 10% of that formed by the wild-type enzyme. About 85% of the O2 consumed was recovered as H2O2. The valine enzyme also exhibited an oxidase activity to yield H2O2 accompanied by a relative decrease in the monooxygenase activity. On the other hand, the serine enzyme exhibited essentially the same monooxygenase activity as that of the wild-type enzyme. Thus, uncoupling of O2 consumption from the monooxygenase function was produced by the substitution of an amino acid without a hydroxyl group. When binding of O2 to the ferrous forms was examined, the alanine and valine enzymes formed instantaneously an oxygenated form, which slowly decomposed to the ferric form with rates of 5.5 and 3.2 x 10(-3) sec-1 for the former and latter enzymes, respectively. Since these rates were too slow to account for the overall rates of O2 consumption, the formation of H2O2 was considered to proceed not by way of this route but through the decomposition of a peroxide complex formed by reduction of the oxygenated form by reduced putidaredoxin. Based on these findings, a possible mechanism for oxygen activation in this monooxygenase reaction has been discussed.

Alanine↗

PubMed1993

Monitoring of bacterial sugars and hydroxy Fatty acids in dust from air conditioners by gas chromatography-mass spectrometry.

Bacterial levels in dust collected from hospital air-conditioning filters were examined by chemical analysis (without prior culture). The dust was analyzed by gas chromatography-mass spectrometry after hydrolysis and derivatization. l-Glycero-d-mannoheptose and hydroxy fatty acids (3-OH 12:0 and 3-OH 14:0) (primarily found in lipopolysaccharide) and muramic acid (a chemical marker for bacterial peptidoglycan) were present at higher levels in dust collected from filters primarily contacting outdoor (as opposed to indoor) air. The ratio of l-glycero-d-mannoheptose to muramic acid in dust (compared with those of a group of gram-positive and gram-negative bacteria) suggested that both dust types contained appreciable numbers of gram-negative bacteria. There is potential for the chemical assessment of the microbial content of airborne dust.

Journal Article↗

PubMedDate not supplied

Spontaneous formation of immunogenic conjugates by 3-hydroxy-para-aminobenzoic acid--a biotransformation product of procaine and para-aminobenzoic acid.

3-Hydroxy-para-aminobenzoic acid (3-HPABA), a biotransformation product of procaine and para-aminobenzoic acid, is capable of binding covalently to proteins by simple incubation at alkaline pH. When administered incorporated in Freund adjuvant to rabbits, 3-HPABA conjugates with normal rabbit serum proteins (3-HPABA-NRS) give rise to both hapten specific antibodies and anti-NRS antibodies. Cross immunological reactions were found between 3-HPABA and ortho-aminophenol (OAP) and 3-hydroxy-sulfanilamide (3-HS) immunological systems, but not between 3-HPABA and para-aminophenol (PAP) and 5-aminosalicyclic acid (5-ASA) immunological systems. The significance of these findings for the explanation of procaine allergy and the possible use of 3-HPABA conjugates for skin testing in procaine hypersensitivity is discussed.

4-Aminobenzoic Acid↗

PubMed1982

Effect of cortisone on the behavior of serotonin, 5-hydroxy-indoloacetic acid and monoaminooxidase in the liver tissue, the blood and the urine in experimental rabbit liver injury with CCl4.

The aim of this study was to investigate the effect of cortisone on the behavior of serotonin metabolism indicators in experiments carried out in rabbits. The following parameters were determined: the level of serotonin (5-hydroxy-tryptamine), (5-HT) in liver tissue and blood, the activity of monoamino-oxidase (MAO) in liver tissue and serum, and the level of 5-hydroxy-indoloacetic acid (5-HIAA) in liver tissue and in 24-hour urine of 52 rabbits. The experimental model involved acute liver injury with carbon tetrachloride--CCl4 and the effect of exogenous cortisone on the behavior of the above-mentioned indicators. On the basis of the experimental findings the authors demonstrate a dependence of serotonin metabolism on the liver injury, and an absence of normalization of the estimated parameters after cortisone administration.

Animals↗

PubMed1987

Measurement of prostaglandins, thromboxanes and hydroxy fatty acids by stable isotope dilution gas chromatography/mass spectrometry.

A method for measurement of PGF2 alpha, PGE1, PGE2, 6-keto-PGF1 alpha, TXB2, 2,3-dinor-TXB2 as well as 5-, 8-, 9-, 11-, 12-, 15-HETE and HHT, utilizing negative ion chemical ionization GC/MS is presented. A highly efficient separation and purification procedure prior to the derivatization sequence allows quantification of the arachidonic acid metabolites described in two GC/MS runs. The detection limit was in the femtomole range. Application of the method to the quantitative profiling of arachidonic acid metabolites in various tissues and incubation media is demonstrated.

Gas Chromatography-Mass Spectrometry↗

PubMed1975

Increased concentrations of nonesterified arachidonic acid, 12L-hydroxy-5,8,10,14-eicosatetraenoic acid, prostaglandin E2, and prostaglandin F2alpha in epidermis of psoriasis.

Lesional epidermis of psoriasis has a probable reduction in the cyclic AMP/cyclic GMP ratio. This altered ratio may in part be responsible for the characteristic glycogen storage, rapid cell proliferation, and reduced differentiation in lesional epidermis. The concentrations of prostaglandins E2 and F2alpha, free arachidonic acid, and 12L-hydroxy-5,8,10,14-eicosatetrawnoic acid in specimens of uninvolved and involved epidermis of psoriasis were measured with deuterium-labeled carriers and multiple ion analysis. Snap frozen specimens contained: 1.4 +/- 0.4 mug/g (wet weight) of arachidonic acid in uninvolved in contrast to 36.3 +/- 16.7 mug/g in involved epidermis (P = 0.015); less than 0.05 +/- 0.01 mug/g of hydroxyeicosatetraenoic acid in uninvolved in contrast to 4.1 +/- 1.9 mug/g in involved epidermis (P = 0.015); 23.6 +/- 5.0 ng/g of prostaglandin E2 in uninvolved in contrast to 33.1 +/- 5.7 ng/g in involved epidermis (P less than 0.01); and 21.0 +/- 4.4 ng/g of prostaglandin F2alpha in uninvolved in contrast to 39.0 +/- 5.9 ng/g in involved epidermis (P less than 0.01). The arachidonic acid and hydroxyeicosatetraenoic acid levels in involved epidermis were strongly correlated (r = 0.97). The increased levels of arachidonic acid and 12L-hydroxy-5,8,10,14-eicosatetraenoic acid in involved epidermis may have diagnostic and pathophysiological importance.

Arachidonic Acids↗

PubMed1989

Analyses of fermentation products of Listeria species by frequency-pulsed electron-capture gas-liquid chromatography.

Aerobic fermentation broths of eight Listeria monocytogenes strains, two or more strains of the remaining six Listeria species, and one strain of Jonesia denitrificans were examined by frequency-pulsed electron-capture gas-liquid chromatography for carboxylic acids, alcohols, amines, and hydroxy acids. All species produced acetic, isobutyric, butyric, isovaleric, phenylacetic, lactic, 2-hydroxybutyric, 2-hydroxyvaleric, and 2-hydroxyisocaproic acids. Propionic acid was not formed, and traces of isocaproic acid were observed. Of the alcohol and amine derivatives observed, only acetylmethylcarbinol, butylamine, and putrecine were identified. Recognition of the products of glucose and amino acid metabolism serves to further characterize the members of the genus Listeria both taxonomically and physiologically.

Acetoin↗

PubMed1983

Identification of 5-hydroxy eicosatetraenoic acid in cerebrospinal fluid after subarachnoid hemorrhage.

To detect and identify lipid peroxides in the CFS following subarachnoid hemorrhage (SAH), CSF samples were obtained sequentially from 10 patients who developed typical vasospasm and were analyzed by HPLC and gas chromatography-mass spectrometry. One of the peaks appearing on the 7th day after SAH was identified as 5-hydroxy eicosatetraenoic acid. On HPLC, an identical peak was detected in samples from other SAH patients. The results gave unequivocal evidence that peroxides of arachidonic acid are present in the CSF following SAH, and a correlation between them and the occurrence of vasospasm seemed likely. The hypothesis that lipid peroxides are involved in the genesis of vasospasm deserves further investigation.

Chromatography, High Pressure Liquid↗

PubMed1978

Motility of human polymorphonuclear leukocytes. Roles of hydroxy fatty acids, other lipids, and cations.

Rapid ionic fluxes across local areas of leukocyte plasma membranes result in local swelling, ie, ruffling or blebbing. These fluxes are stimulated either locally or generally over the cell membranes by hydrophobic chemotactic peptides. This swelling is associated with migration of the cells in the direction of the swollen area of the cell. Hydroxy fatty acids, other lipids, and Ca++ ionophores activate a Ca++-dependent migratory activity of the cell, whereas acidic peptides activate a monovalent cation-dependent migratory activity. These two processes are therefore additive. The swelling due to the peptides results in an increase in urea space but no change in inulin space, whereas, swelling due to permeant cations and anions causes a massive increase in both spaces. Migration appears to result from the pushing of cellular contents, nucleus and cytoplasm, into the more swollen area of the cell by unopposed contraction of the unswollen area of the cell.

Calcium↗

PubMed2003

15-hydroxy-eicosatetraenoic acid arrests growth of colorectal cancer cells via a peroxisome proliferator-activated receptor gamma-dependent pathway.

Peroxisome proliferator-activated receptor gamma (PPARgamma) inhibits cell growth via promoting apoptosis. Human colorectal cancer tissues had abundant PPARgamma but the incidence of apoptosis was very low, suggesting a defect in the PPARgamma pathway. Here, we found that 15-hydroxy-eicosatetraenoic acid (15S-HETE), an endogenous ligand for PPARgamma, was significantly decreased in the serum of patients with colorectal cancer. Treatment of colon cancer cells with 15S-HETE inhibited cell proliferation and induced apoptosis, which was preceded by an increase in TGF-beta-inducible early gene (TIEG) and a decrease in Bcl-2. The action of 15S-HETE could be blocked when PPARgamma was suppressed. Overexpression of Bcl-2 prevented the apoptosis. The levels of TIEG and 15-lipoxygenase (15-LOX), the enzyme responsible for 15S-HETE production, was decreased in colorectal cancer. Therefore, colorectal cancer is associated with decreased 15S-HETE. Treatment of colon cancer cells with 15S-HETE inhibits cell proliferation and induces apoptosis in a PPARgamma-dependent pathway involving augmentation of TIEG and reduction of Bcl-2 expression.

Apoptosis↗

PubMed1986

Dermis-derived 15-hydroxy-eicosatetraenoic acid inhibits epidermal 12-lipoxygenase activity.

The purpose of the present study was to analyze the metabolism of arachidonic acid (AA) in normal human dermis. After incubating homogenized dermis with exogenous AA, the extracted lipids were isolated by reversed-phase high-performance liquid chromatography. Each chromatographic peak was characterized by its UV absorption spectrum and identified by its coelution with the appropriate authentic standard and by radioimmunoassay of its eluate fraction. Identified compounds were quantitated by integrated optical density. Homogenized human dermis transformed AA into both cyclooxygenase and lipoxygenase products, but predominantly 15-hydroxy-eicosatetraenoic acid (15-HETE). Cultured fibroblasts from normal human dermis also mainly metabolized AA into 15-HETE. To determine whether dermis-derived 15-HETE might modify the AA metabolism of epidermis, normal human epidermis was incubated with dermis. Increasing amounts of dermis resulted in an increasing inhibition of epidermal 12-HETE formation. Similarly, 15-HETE alone induced a dose-dependent decrease of epidermal 12-HETE formation, while the formation of prostaglandin E2 was unchanged. Since 12-HETE possess the ability to elicit skin inflammation and to stimulate epidermal DNA synthesis, 15-HETE formation may be a way whereby dermis regulates important epidermal activities.

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

PubMed1981

Interactions between stimulated platelets and endothelial cells in vitro.

Prostaglandins and hydroxy acids are synthesized mainly from the essential polyunsaturated fatty acid arachidonate, and these substances have been identified in almost all mammalian tissues. Prostaglandins, thromboxane A2 (TXA2) and prostacyclin (PGI2) are autocoids that appear to function in the regulation of vascular tone, cell secretion and contractile processes. So far, hydroxy acids have been found to function as chemotactic agents and in the formation of slow-reacting substances. Other actions of hydroxy acids will certainly be defined in future research. The endoperoxides PGG2 and PGH2 represent common precursors of all prostaglandin end-products. In studying the prostaglandin metabolism of a specific tissue, the total profile of endoperoxide transformation should be determined. In platelets the endoperoxides are transformed mainly into TXA2, a potent vasoconstrictor and inducer of platelet aggregation. Endothelial cells convert endoperoxides to PGI2, a vasodilator and inhibitor of platelet aggregation. In addition, endothelial cells can utilize endoperoxides from stimulated plates to form PGI2. The concept that platelets and endothelial cells can share common precursors for the production of modulating substances may be applicable to other cell types.

Arachidonic Acids↗

PubMed1976

Binding of spirolactones to human plasma proteins.

The lipophilicity and plasma binding of 16 spirolactones and 4 hydroxy acid analogs were determined. Mathematical expressions were derived to correlate quantitatively the extent of plasma binding to the lipophilicity of the drugs. The nonspecific binding of these spirolactones and their hydroxy acid analogs was also analyzed using purified serum albumin. A computer program was developed to examine the mechanism of drug-serum protein interactions. One class of binding sites was observed for the range of concentrations used. The number of binding sites and the equilibrium binding constant were computed and were sensitive to substitution at the C-6 and C7 positions. Hydrolysis of the C-17 lactone ring in spirolactones to form hydroxy acid analogs resulted in a decrease in the lipophilicity and, hence, the equilibrium constant for binding.

Binding Sites↗

PubMed1995

In vitro and in vivo biotransformations of the naphthalenic lignan lactone 5-lipoxygenase inhibitor, L-702,539.

It has been reported previously that the tetrahydropyranyl naphthtalenic lignan lactone L-702,539 is a potent nonredox, 5-lipoxygenase inhibitor that has the advantage that it can be dosed either as the lactone or as the corresponding nonactive hydroxy acid L-702,618 (opened lactone). Studies with hepatic microsomes from the rat, rhesus monkey, and human were undertaken in a phosphate buffer and suggested that the closure of the hydroxy acid L-702,618 to the lactone L-702,539 was an enzymatic process. The incubation of L-702,539 under oxidative conditions with these specific hepatic microsomes resulted in the formation of three significant metabolites (> 0.4 nmol/mg protein/hr) as determined by HPLC with UV detection. These metabolites were isolated from large microsomal incubations and were characterized by MS and NMR spectroscopy. Data showed that the lactone and tetrahydropyran portions of the molecule were both susceptible to hydroxylation, and the hydroxylated tetrahydropyran was further oxidized to the hydroxy acid. Analysis of plasma samples obtained from rat and rhesus monkeys following L-702,618 administration indicated that the in vivo metabolic pathway was similar to the one observed in vitro using hepatic microsomes. Studies conducted with microsomes from genetically engineered human cell lines expressing individual cytochrome P450s indicated that the isozyme responsible for the metabolism at the tetrahydropyran ring, was P4503A4. These findings were supported by studies conducted in human microsomes using an inhibitory P4503A4 antibody and troleandomycin, which is a potent P4503A inhibitor.

Animals↗