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Results for “Homovanillic Acid”

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At least 127 records · Page 7Linked to original sources
PubMed1977

Nonhomogeneous distribution of 5-hydroxyindoleacetic acid and homovanillic acid in the lumbar cerebrospinal fluid of man.

The volume of the lumbar sac measured in 4 subjects was found to be 15.5 ml. Exactly 15 ml of lumbar cerebrospinal fluid (L-CSF) was permitted to flow freely out during a lumbar puncture in 20 neurological patients and small samples of the L-CSF were collected in the beginning (sample 1), at the middle (sample 2), and at the end (sample 3) of this procedure either for 5-HIAA or HVA measurement. The concentrations of 5-HIAA and HVA increased in an exponential manner from sample 1 to sample 3. These results indicate that CSF in the lumbar sac is not a homogeneous fluid as is generally believed and that certain rules have to be followed in the sampling of the L-CSF to obtain reproducible biochemical data.

Adult↗
PubMedDate not supplied

[Usual values for 5-hydroxy-indol acetic acid and homovanillic acid in cerebrospinal fluid].

The aim of this work was to reinvestiagte usual values of neurotransmitter catabolites (5-HIAA and HVA) in CSF, their determination being a current method for studying pathological processes and/or drug induced changes on CNS metabolism. 5-HIAA and HVA have been measured by reverse phase HPLC and electrochemical detection. Since many confounding factors have been identified to modify the concentration of both analytes in CSF, data from 1.480 patients have been revisited with strict exclusion and 323 have been selected. Age dependent variation and asymetric distributions were observed. Age-related usual values ranges were established after identification of outliers by non-parametric analysis. In a group of patients for which repeated CSF collection have been performed for the follow up of acute leukemia, wide and unpredictible individual variations (up to 400 %) of CSF 5-HIAA and HVA concentrations have been observed. These large interindividual and individual variations may explain the numerous discrepancies found in studies investigating the CNS monoamine metabolism, especially when small groups of patients are used. Such observation limits the interpretation of monoamine metabolic for diagnostic purposes without a strict selection of indication.

Adolescent↗
PubMed1987

Determinations of 5-hydroxyindoleacetic acid and homovanillic acid in human CSF with monitoring of probenecid levels in CSF and plasma.

The accumulation of 5-HIAA and HVA in cerebrospinal fluid (CSF) was studied in eight healthy volunteers after oral administration of probenecid. Simulation indicated that a dose of 4.5 g probenecid should be used to achieve probenecid plasma concentrations between 200 and 400 micrograms/ml. Almost complete inhibition of the active transport of the acidic metabolites was assumed to be obtained at these concentrations. Probenecid 4.5 g was administered in two doses (2.5 g and 2 g), separated by 4 h. Plasma samples were drawn at varying intervals over a period of 46 h and lumbar puncture (LP) was performed at either 14 h or 20 h after the first administration of probenecid. The concentration of probenecid, 5-HIAA and HVA in CSF was estimated and the probenecid-induced accumulation of 5-HIAA and HVA was compared with their baseline values. There were no statistically significant differences (P greater than 0.05) in the accumulation of the monoamine metabolites between the two LP (14 h and 20 h), neither were there any differences in CSF concentrations of probenecid at the time of LP. There were only small differences in probenecid plasma concentrations, although statistically significant. Due to maximum blockade of the active transport system no correlation was observed between the CSF concentration of probenecid and the induced accumulation of 5-HIAA and HVA, respectively. The range of probenecid-induced accumulation for 5-HIAA and HVA in these volunteers was 156-429% and 183-600%, respectively. The suggested monitoring of probenecid plasma levels is proposed as a suitable model to investigate central neuronal activity of dopamine and serotonin in the central nervous system.

Adult↗