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At least 19 recordsLinked to original sources
PubMed1977

[A simple method for the simultaneous analysis of urinary homovanillic acid, vanilmandelic acid and 3, 4-dihydroxy mandeli acid by mass fragmentography (author's transl)].

Gas chromatography-mass spectrometry makes possible the simultaneous measurement of homovanillic acid (HVA), vanilmandelic acid (VMA) and 3, 4-dihydroxy mandelic acid (DOMA) in 2ml urine samples. The equipment used was the Shimadzu LKB 9000 GC-MS (MID-PM). The TMSi derivatives of the compounds were analysed by the GC-MS system equipped with a 3ft. X 3mm column packed with 1.5% OV-1 and the temperature was programed from 130 degrees to 260 degrees C at 10 degrees C/min increments. The mass spectrum showed molecular ions at m/e 326, 414, and 472 which correspond to the TMSi derivatives of HVA, VMA AND DOMA respectively. The peaks at m/e 326 (HVA), 297 (VMA) and 355 (DOMA) were applied to avail themselves of simultaneous multiple ion analyses by GC-MS. As little as 1pg of the compounds injected into the column could be measured reproducibly. The sensitivity is of the order of pg or ng, and the linearity of the response is maintained up to at least 200ng. The procedure was simpler and less time consuming than previous methods. It consists of extraction of the free acid into ether followed by complete silylation of the phenolic, alcoholic and carboxylic acid group with bis (trimethylsilyl) acetamide. Recoveried of HVA, VMA, DOMA added to urine were 93.8%, 71.2% and 23.6% respectively. The specificity of this method surpasses and cannot be compared to any other existing quantitative methods.

Gas Chromatography-Mass Spectrometry↗
PubMed1985

Blood pressure, 5-OH indoleacetic acid, and vanilmandelic acid excretion and blood platelet aggregation in hypertensive patients treated with ketanserin.

Ketanserin, a new selective 5-HT2-serotonergic antagonist, was used to: confirm its hypotensive efficacy in acute and long-term treatment, determine its influence on the influence on the metabolism of serotonin (5-HT) and catecholamines, and elucidate their mutual relationship. Ketanserin was given intravenously to 10 patients with hypertensive crisis or resistant hypertension and orally to 15 patients with mild to severe hypertension for 1 year. Blood pressure, heart rate, 24-h urinary excretion of vanilmandelic acid (VMA; the major endproduct of catecholamines) and of 5-hydroxyindoleacetic acid (HIAA; the endproduct of serotonin metabolism), and platelet aggregation were measured. In doses normalizing blood pressure and platelet aggregation, ketanserin administered to hypertensive patients either intravenously in acute treatment or orally in chronic treatment caused: (a) decreased HIAA excretion (more marked in chronic than in acute treatment) and (b) simultaneous decrease in VMA excretion. It is concluded that the decisive sites of ketanserin action are the 5-HT2 receptors of platelets. The compound reduces platelet aggregation and the release of 5-HT, its metabolism, and, hence, the excretion of HIAA. The action of ketanserin on 5-HT2 receptors of vascular smooth muscle participates in the hypotensive effect of the drug but does not explain the decreased excretion of HIAA and VMA.

Adult↗
PubMed1982

Influence of UV- and capsaicin-induced erythema as well as of acetylsalicylic acid on the urinary excretion of vanilmandelic acid and homovanillic acid in man.

In the present study we investigated whether by means of urinary excretion of vanilmandelic acid (VNA) and homovanillic acid (HVA), resp., the two main metabolites of adrenaline, noradrenaline and dopamine, informations could be obtained on synthesis and release of catecholamines in inflammation. UV- and capsaicin-induced erythema, resp., were used as the inflammatory models. The urinary excretion or both VMA and HVA were found to be decreased after UV irradiation. Administration of acetylsalicylic acid during UV irradiation inhibited the decrease of VMA excretion whereas HVA excretion remained low. The application of capsaicin as a plaster failed to influence the urinary VMA and HVA excretion. Our results could be explained on the basis of the interrelationship between catecholamines and prostaglandins. Other possible mechanisms are discussed.

Adult↗
PubMed1993

Simultaneous analysis of homovanillic acid, 5-hydroxyindoleacetic acid, 3-methoxy-4-hydroxyphenylethylene glycol and vanilmandelic acid in plasma from alcoholics by high-performance liquid chromatography with electrochemical detection. Critical comparison of solid-phase and liquid-liquid extraction methods.

A method is described for the simultaneous determination of vanilmandelic acid, 3-methoxy-4-hydroxyphenylethylene glycol, 5-hydroxyindoleacetic acid, and homovanillic acid in a human plasma sample using reversed-phase high-performance liquid chromatography with column switching and amperometric detection. Two methods of sample preparation were tested. Liquid-liquid extraction yields better recoveries, is more selective and precise than solid-phase extraction and allows a shorter time of chromatographic analysis. Estimated plasma values of the metabolites from healthy controls are in good agreement with previously reported levels. Studies of alcoholics at the beginning of the delirium tremens provided different plasma levels of the metabolites, dependent on the different duration--and hence the severity--of the delirium.

Alcohol Withdrawal Delirium↗
PubMed1984

Measurement of urinary vanilmandelic acid and homovanillic acid by high-performance liquid chromatography with electrochemical detection following extraction by ion-exchange and ion-moderated partition.

An improved protocol has been developed to isolate homovanillic acid (HVA) and vanilmandelic acid (VMA) from urine with strong anion-exchange resin. The sample is diluted with acetate buffer and passed through a disposable column. HVA, uric acid, and many hydrophobic organic acids are removed with 1.0 M acetic acid--ethanol. Then VMA is eluted with 0.5 M phosphoric acid. Two isocratic mobile phases allow rapid high-performance liquid chromatographic measurement of VMA (5 min) and HVA (8 mins) on a 5-micron ODS column. Selective conditions were developed with dual-electrode coulometric detection to permit specific measurement of VMA, HVA, and internal standards, with less than 5% between-run variation.

Chromatography, High Pressure Liquid↗