Assay for dopamine beta-hydroxylase in human plasma and rat serum by high-performance liquid chromatography with fluorimetric detection

Peripheral markers of catecholamine metabolism among workers occupationally exposed to manganese (Mn)

In a preliminary study of 11 men randomly selected in a ferro-alloy plant and of 15 control subjects, platelet monoamine oxidase (MAO) and serum dopamine beta-hydroxylase (DBH) activities were measured. A tendency towards lower MAO-B activity in the exposed workers as compared to control subjects (t = 1.95; P = 0.06) was found whereas DBH activity was similar. In the exposed group, a dose-effect relationship was noted between a manganese (Mn) cumulative exposure index (CEI) and DBH activity (R2 = 0.40, P < 0.05). Since DBH is an expression of catecholamine release, the relative increase in such activity could be envisaged as a compensatory mechanism to a reduced turnover rate as reflected by MAO-B activity. Owing to the limited sample size, these findings should be confirmed by further epidemiological and experimental studies.

Application of high-performance liquid chromatography to the study of biogenic amine-related enzymes

The application of high-performance liquid chromatography to the study of biogenic amine-related enzymes is reviewed. Biogenic amines include catecholamines (dopamine, norepinephrine and epinephrine), indoleamines (serotonin and melatonin), imidazoleamines (histamine), polyamines (putrescine, spermidine and spermine) and acetylcholine. Three particular aspects are covered. The first aspect is the assay of enzyme activities of biogenic amine-related enzymes, such as tyrosine hydroxylase, tryptophan hydroxylase, aromatic L-amino acid decarboxylase, dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase. The introduction of highly sensitive assays of biogenic amines with electrochemical detection or fluorescence detection have made possible the non-isotopic assay of these activities, replacing the previously used radioisotopic methods. The second aspect is the purification of these enzymes. Since biogenic amine-synthesizing enzymes are generally unstable, rapid and efficient purification of these enzymes is very useful. The third aspect is the assay of biogenic amines (for example, acetylcholine and polyamines) using post-column derivatization with biogenic amine oxidases and electrochemical detection.

Clinical and genetic relationships between autism-pervasive developmental disorder and Tourette syndrome: a study of 19 cases

Children with autism or pervasive developmental disorder (PDD) and Tourette syndrome (TS) share a number of symptoms. Forty-one cases have been reported in which PDD patients subsequently developed TS. We term this PDD----TS. We describe an additional 16 such patients plus 3 families where a close relative of a TS proband had autism. There was a high frequency of alcoholism, drug abuse, obsessive-compulsive, and other behavior disorders in the relatives of these patients. This frequency was virtually identical to that observed in relatives of individuals with TS only. We suggest there is an intimate genetic, neuropathologic relatedness between some cases of PDD and TS. Many observations have led us to suggest that the genetic defect in TS may be a mutation of tryptophan oxygenase and that TS is inherited as a semidominant semirecessive trait, i.e., homozygosity for a common gene which shows some expression in the heterozygous state. We propose that some types of PDD are inherited in the same fashion and by the same gene. This would explain the similarity of symptoms, frequent evolution of PDD into TS, the apparent recessive inheritance of PDD despite no increase in consanguinity, the high frequency of behavior problems in the relatives of PDD----TS patients and the serotonin abnormalities.

Determination of catecholamines in human plasma by high-performance liquid chromatography: comparison between a new method with fluorescence detection and an established method with electrochemical detection

We report a sensitive fluorimetric method, in which catecholamines are concentrated from plasma by liquid-liquid extraction and derivatized with the selective fluorescent agent 1,2-diphenylethyl-enediamine prior to chromatography. Optimal conditions for extraction, derivatization and chromatography were investigated. With alpha-methylnorepinephrine as internal standard, the chromatographic separations are complete within 6 min. Limits of detection are 0.3 pg for norepinephrine and epinephrine and 0.5 pg for dopamine. Coefficients of variation are low (3-7%). Comparison of plasma catecholamine values determined with this method and with an established method with electrochemical detection (n = 135) shows good correlation (r = 0.94-1.00), and regression lines are close to lines of identity.