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PubMed1977

Comparative study of urinary excretion rates of para-hydroxy-mandelic acid, homovanillic acid, vanylmandelic acid in cirrhotic patients with and without encephalopathy.

A comparative study of urinary excretion of octopamine, dopamine, and noradrenaline catabolic products, respectively parahydroxymandelic acid (PHMA) homovanillic acid (HVA) and vanylmandelic acid (VMA) was carried out in 27 cirrhotic patients with (11) and without (16) porto-systemic encephalopathy (P.S.E). PHMA, HVA and VMA were significantly higher in patients with PSE, and there was a positive correlation between PHMA and HVA, and between PHMA and VMA. Higher excretion of PHMA in patients with PSE strongly suggests an increased metabolism of octopamine. HVA and VMA increased excretion, and the positive correlations could be explained by the depletion of stored dopamine and noradrenaline. These observations support the hypothesis that octopamine acts as a false neurotransmitter, and the resulting depletion of dopamine and noradrenaline could explain the neuropsychic phenomena of PSE, and the awakening effect of L. Dopa treatment.

Aged↗
PubMed1991

Selective reduction of oxo bile acids: synthesis of 3 beta-, 7 beta-, and 12 beta-hydroxy bile acids.

Preparation of some biologically important keto bile acids is described. Advantage is taken of the preferential ketalization of 3-oxo group in bile acids over 7- and 12-oxo groups for the selective reduction of these keto groups. The method was found to be specially useful for preparation of 7 beta-, 12 alpha, and 12 beta-[3H]-3-oxo bile acids. Improved methods are also described for the preparation of epimers of naturally occurring bile acids at C-3, C-7, and C-12. 3 beta-Hydroxy bile acids (iso-bile acids) were prepared with the use of diethylazodicarboxylate/triphenylphosphine/formic acid. Iso-bile acids were obtained in excellent yields (80-95%) except during synthesis of isoursodeoxycholic acid (yield, 50%). Isoursodeoxycholic acid was, however, prepared in very good yield via epimerization of 3 alpha-hydroxyl group in 7-oxolithocholic acid followed by stereoselective reduction of 7-oxo group. A highly efficient method for the reduction of 7-oxo and 12-oxo groups was developed. Thus, 7-oxolithocholic acid and 7-oxoisolithocholic acid on reduction with potassium/tertiary amyl alcohol yielded ursodeoxycholic acid and isoursodeoxycholic acid in yields of 96% and 94%, respectively, while reduction of 7-oxodeoxycholic acid resulted in ursocholic acid in 93% yield. In a similar manner, reduction of 12-oxolithocholic acid and 12-oxochenodeoxycholic acid yielded 3 alpha, 12 beta-dihydroxy-5 beta-cholanoic acid (lagodeoxycholic acid; 92% yield) and 3 alpha, 7 alpha, 12 beta-trihydroxy-5 beta-cholanoic acid (lagocholic acid, 86% yield).

Bile Acids and Salts↗
PubMed1993

Formation of prostanoids and hydroxy fatty acids by stimulated peritoneal mast cells: role of the dietary fat type in rat.

To study the influence of membrane fatty acid composition on the formation of prostanoids and hydroxy fatty acids by rat peritoneal mast cells (MC), animals were fed three different types of fatty acids: mackerel oil (MO), abundant in n-3 fatty acids; sunflower seed oil (SO), rich in linoleic acid; and hydrogenated coconut oil (HCO), mainly containing saturated fatty acids. The presence of n-3 fatty acids in the diet resulted in the incorporation of 20:5(n-3), 22:5(n-3) and 22:6(n-3) in MC phospholipids. A decrease of arachidonic acid, 20:4(n-6), was observed in MC-phospholipids of the MO-fed animals. Furthermore, increasing the relative amounts of 18:2(n-6) in the diet (SO group) led to an increased incorporation of linoleic acid, 18:2(n-6) in MC phospholipids when compared to both other dietary groups. The changes in MC phospholipid fatty acid composition were (partly) reflected in the formation of prostanoids and hydroxy fatty acids upon stimulation with the calcium ionophore A23187. The decrease in arachidonic acid content in MC phospholipids of MO-fed rats resulted in a decreased formation of PGD2 when compared to both other groups. Also, the increased amounts of 18:2(n-6) in MC phospholipids of SO-fed rats resulted in an increased formation of 9- and 13-HODE upon stimulation. The results show that modifications in the fatty acid composition of the diet influences MC membrane fatty acid composition which ultimately results in changes in prostanoid and hydroxy fatty acid synthesis by MC upon stimulation with the calcium ionophore A23187.

Animals↗
PubMed1994

Systematic study of the 3-hydroxy fatty acid composition of mycobacteria.

Twenty-seven strains belonging to 12 Mycobacterium species were studied for 3-hydroxy fatty acid composition. Mycobacterial cells were subjected to both mild and strong acid methanolysis, after which the liberated hydroxy fatty acids were purified and analyzed by gas chromatography-mass spectrometry as methyl ester trimethylsilyl ether derivatives. Altogether, 21 3-hydroxy fatty acids containing 14 to 28 carbon atoms were detected; 10 were straight chain, 6 were 2-methyl branched chain, and 5 were 2,4,6-trimethyl branched chain. The mycobacterial strains were classified in groups according to 3-hydroxy fatty acid patterns.

Esterification↗
PubMed1992

Hydantoin bioisosteres. In vivo active spiro hydroxy acetic acid aldose reductase inhibitors.

The hypothesis that clinical side effects of the aldose reductase inhibitor (ARI) sorbinil were related to its hydantoin ring led to a bioisosteric analysis and replacement of the hydantoin by a spiro hydroxy acetic acid moiety as in 40. These hydroxy acids, compared to hydantoins, showed a similar potency increase on chroman 2-methyl substitution, a similar orthogonal relationship of acidic to aromatic moieties, and similar ARI enantioselectivity. In this series the six-membered spiro hydroxy acetic acid anion array is a bioisostere for a spiro hydantoin anion and leads to ARIs with excellent in vivo activity. In vitro and in vivo activity was improved over 40 by chroman cis 2-methylation as in 4 and by aromatic 6,7-halogen substitution. Compounds with the best acute in vivo activity in rats were compared for chronic in vivo activity. The highest tissue levels and best chronic in vivo activities were found in the racemic 6,7-dichloro and 6-fluoro-7-chloro analogues 18 and 23. ARI activity was enantioselective for 58 and 60, the 2R,4R-enantiomers of 18 and 23. 7-Chloro-6-fluoro-cis-4-hydroxy-2(R)-methyl-chroman-4-acetic acid (60) was selected for phase 1 clinical trials and did not exhibit sorbinil-like hypersensitivity side effects.

Aldehyde Reductase↗
PubMed2004

Hydrophilic 7 beta-hydroxy bile acids, lovastatin, and cholestyramine are ineffective in the treatment of cerebrotendinous xanthomatosis.

We compared the effect of treatments with hydrophilic bile acids (ursodeoxycholic and ursocholic acids), cholestyramine, and lovastatin versus chenodeoxycholic acid in 4 patients with cerebrotendinous xanthomatosis (CTX). Bile acids and bile alcohols in plasma, bile, and urine before and after treatment were quantitated by gas-liquid chromatography. Untreated, all patients showed abnormal biliary bile acid composition: cholic acid (72.7%) and chenodeoxycholic acid (6.2%), and polyhydroxylated C(27)-bile alcohols (10.0%), and elevated plasma cholestanol levels. Treatment with hydrophobic chenodeoxycholic acid inhibited abnormal bile acid synthesis (virtual disappearance of C(27)-bile alcohols from plasma, bile, and urine and marked reduction of plasma cholestanol levels). Hydrophilic ursodeoxycholic and ursocholic acids did not inhibit abnormal bile acid synthesis, while cholestyramine increased abnormal bile acid synthesis (continued increased formation of polyhydroxylated C(27)-bile alcohols and further elevation of plasma cholestanol levels). Lovastatin did not affect abnormal bile acid synthesis or reduce plasma cholestanol levels. The results demonstrate that impaired side-chain oxidation in bile acid synthesis due to mutations of Cyp27 results in increased formation of polyhydroxylated C(27)-bile alcohols and cholestanol in CTX. Hydrophobic chenodeoxycholic acid, but not cholestyramine, lovastatin, or hydrophilic 7beta-hydroxy acids, inhibited the abnormal synthetic pathway. The role of chenodeoxycholic acid in downregulating abnormal bile acid synthesis in CTX is emphasized.

Adult↗
PubMed2005

The glycosphingolipid receptor for Vibrio trachuri in the red sea bream intestine is a GM4 ganglioside which contains 2-hydroxy fatty acids.

Three major glycosphingolipids (tentatively designated IGL-1, 2, and 3) were isolated from the intestine of red sea bream (Pagrus major) and were subjected to a TLC-overlay assay with (35)S-labeled Vibrio trachuri which causes vibriosis of fish. The bacteria adhered to IGL-2, which was determined to be a GM4 ganglioside (NeuAcalpha2-3Galbeta1-ceramide). The fatty acid portion of IGL-2 was composed of 2-hydroxy C22:0, C24:0, and C24:1, in addition to the non-hydroxy C16:0 and C18:0, while the sphingoid base was composed exclusively of sphingenine (d18:1). Among glycosphingolipids tested, V. trachuri adhered to GM4 the most strongly followed by adherence to GM3 and GalCer, but the bacteria did not adhere to GM1a, GM2, LacCer, or GlcCer. V. trachuri was found to aggregate with the erythrocytes coated with GM4, but not with those coated with GM1a or GM2, thus indicating that specific adhesion occurs on intact cells. Interestingly, the dynamics for adhesion of V. trachuri to glycosphingolipids was defined by the structure of not only the sugar moiety but also the ceramide moiety, since the bacteria adhered to GM4 which contained 2-hydroxy fatty acids much more strongly than to that which contained non-hydroxy fatty acids.

Animals↗
PubMed1983

Comparison of the effects of acid and base hydrolyses on hydroxy and cyclopropane fatty acids in bacteria.

The cellular fatty acid compositions of Legionella oakridgensis, Brucella suis, Pseudomonas aeruginosa, and Francisella tularensis were compared after base hydrolysis (saponification), acid hydrolysis, and acid methanolysis procedures were used to release the fatty acids. The branched-chain, unsaturated, saturated, and ester-linked hydroxy acids were released as effectively with saponification at 100 degrees C for 30 min as with acid hydrolysis or acid methanolysis at 85 degrees C for 16 h. Although the amide-linked hydroxy acids were released more effectively by acid hydrolysis or acid methanolysis, these methods degraded the cyclopropane fatty acids, producing a number of new peaks or artifacts in the chromatograms. Cyclopropane fatty acids were not degraded by saponification, and at least 50% of the hydroxy acids were released when the cells were saponified with 15% NaOH in 50% aqueous methanol. Thus, the results show that saponification for 30 min at 100 degrees C with 15% NaOH, followed by methylation is an excellent method for routine fatty acid analysis of bacteria and for screening cultures whose identity and fatty acid composition are unknown.

Bacteria↗
PubMed1991

4-halo-3-hydroxyanthranilic acids: potent competitive inhibitors of 3-hydroxy-anthranilic acid oxygenase in vitro.

The mechanism of action of three potent inhibitors of 3-hydroxyanthranilic acid oxygenase (3HAO), the enzyme responsible for the production of the endogenous excitotoxin quinolinic acid, was examined in vitro. Using either liver homogenate or purified 3HAO, and following the rapid synthesis of the immediate enzymatic product alpha-amino-beta-carboxymuconic acid omega-semialdehyde spectrophotometrically, 4-halogenated (F, Cl, Br) 3-hydroxyanthranilic acids were found to inhibit enzymatic activity in a reversible fashion. Because of the very tight binding of the drugs to 3HAO, reversibility was detected only after warming the protein-inhibitor complexes at 37 degrees. Further studies showed that enzyme inhibition was competitive in nature (apparent Ki values: 190, 6 and 4 nM for the F-, Cl- and Br-compounds, respectively), and suggested that the drugs are metabolized by the enzyme. Specific, reversible, and tightly binding 3HAO inhibitors can be expected to become valuable tools for the study of quinolinate neurobiology. The drugs could also be of interest for the diagnostics and therapeutics of brain diseases which have been speculatively linked to a pathological overabundance of quinolinic acid.

3-Hydroxyanthranilic Acid↗
PubMed1979

Suicide inactivation of the flavoenzyme D-lactate dehydrogenase by alpha-hydroxybutynoate.

The acetylenic alpha-hydroxy acid 2-hydroxy-3-butynoate (alpha HB) is a substrate and an irreversible inactivator of the FAD-containing flavoenzyme D-lactate dehydrogenase from Megasphaera elsdenii. On the average, the enzyme undergoes five catalytic turnovers with alpha HB in air at pH 7.0 before being inactivated. Irreversible inactivation is due to the conversion of the flavin to a pink adduct with visible absorption peaks at 522, 382, and 330 nm and weak fluorescence with an emission maximum at 635 nm. The adduct is stable and can be released from the enzyme and purified. It retains a structure analogous to FAD since it binds to the FAD-specific apo-D-amino acid oxidase. It can be further converted to an FMN analogue with phosphodiesterase which binds to the FMN-specific apoflavodoxin. Experiments were conducted to test whether inactivation was initiated by an alpha HB allene carbanion or the dehydrogenation product of alpha HB. Kinetic studies proved inconclusive in that a rapid equilibrium between an oxidized enzyme--allene carbanion pair and reduced enzyme--keto acid pair would make these two species kinetically equivalent. The olefinic substrate 2-hydroxy-3-butenoate, however, produced no flavin adduct. Since the keto acid derived from the oxidation of this alpha-hydroxy acid is expected to be as reactive as 2-keto-3-butynoate, it is concluded that an allene carbanion produced by abstraction of the alpha-hydrogen of alpha HB is the reactive species which covalently adds to the flavin.

Alkynes↗
PubMed1996

Epidermal and dermal effects of topical lactic acid.

BACKGROUND: Many alpha-hydroxy acid products, containing low- or high-acid concentrations, are being used. It is not known whether different products perform differently or whether they modulate changes in both the epidermis and dermis. OBJECTIVE: The purpose was to examine whether treatment with 5% and 12% lactic acid produces different cosmetic results and produces changes in the epidermis and dermis. METHODS: Test participants applied either 5% or 12% lactic acid twice a day for 3 months. Changes in skin smoothness and texture, the depth and number of lines and wrinkles, and epidermal and dermal firmness and thickness were determined. RESULTS: Treatment with 12% lactic acid resulted in increased epidermal and dermal firmness and thickness and clinical improvement in skin smoothness and in the appearance of lines and wrinkles. No dermal changes were observed after treatment with 5% lactic acid; however, similar clinical and epidermal changes were noted. CONCLUSION: The results demonstrate that cosmetic benefits from the use of alpha-hydroxy acids are caused by modification of the skin surface, the epidermis and the dermis. Although 5% lactic acid modulates surface and epidermal changes, 12% lactic acid influences both the epidermis and the dermis.

Administration, Cutaneous↗
PubMed1975

Identification of microorganisms by gas chromatographic-mass spectrometric analysis of cellular fatty acids.

The cellular fatty acid compositions of strains of Pseudomonas aeruginosa, P. cepacia, and P. maltophilia were determined by gas-liquid chromatography. A variety of acids was detected in these organisms, including branched and straight-chain acids, cyclopropane, and hydroxy acids. Comparison of the presence and relative amounts of these acids was useful in distinguishing the three species. Three branched-chain hydroxy acids not found in other bacteria were present in P. maltophilia and were identified by gas chromatography, mass spectrometry, and infrared spectroscopy.

Cell Wall↗