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Biomedical subjects

M N McLeod

Publications and source records attributed to M N McLeod.

7 recordsLinked to original sources

Catechol-O-methyltransferase activity and classification of depression.

Red blood cell catechol-O-methyltransferase (COMT) activity was compared across different depressive diagnoses. In a sample of 88 depressed inpatients, using defined criteria, no difference was found in respect of enzyme activity and the following categories: primary, secondary, delusional, nondelusional, endogenous, nonendogenous (neurotic), characterological depressions. COMT did not vary with age or sex. A significant increase in COMT activity was noted in agitated, depressed males, as compared to other groups.

Adult

Acetylation phenotype, platelet monoamine oxidase inhibition, and the effectiveness of phenelzine in depression.

The authors treated 16 depressed patients with up to 90 mg/day of phenelzine. After acetylation phenotype was determined and platelet monoamine oxidase (MAO) activity measured, no significant relationship was observed between clinical improvement and acetylation phenotype or between MAO inhibition and acetylation. Discrepant findings regarding acetylation phenotype and the effects of phenelzine are discussed. The authors do not recommend a sulfamethazine phenotype test as a predictor of outcome for phenelzine.

Acetylation

Inhibition of platelet monoamine oxidase in depressed subjects treated with phenelzine.

The authors treated 19 depressive inpatients double-blind with a mean dose of 78 mg/day of phenelzine for 3 weeks to determine the possible relationship between monoamine oxidase (MAO) inhibition and the effectiveness of phenelzine. Clinical ratings made on the Hamilton Depression Rating Scale, the Beck Depression Inventory, and the SCL-90 indicated a minimum of 60% MAO inhibition had to be achieved for the drug to be consistently beneficial.

Blood Platelets

Antidepressant drug therapy in psychotic depression.

Imipramine and phenelzine were ineffective in the treatment of five primary unipolar depressives with delusions, even when plasma levels of imipramine and desmethylimipramine or activity of platelet monoamine oxidase suggested that an adequate dose of drug had been given. Four patients went on to receive ECT and all responded well. Five non-delusional patients responded satisfactorily to the antidepressant drug given. Nine out of ten subjects were women. Non-delusional patients showed some placebo response. ECT is considered to be the treatment of choice in the acute phase of delusional depression in women.

Adult

Platelet monoamine oxidase activity in schizophrenia.

The activity of platelet monoamine oxidase in 12 chronic schizophrenic patients was not significantly different from that in a matched group of normal individuals. The authors emphasize the importance of simultaneous processing of control and patient blood samples and the use of carefully controlled techniques, since relatively minor changes in procedure can markedly influence platelet yield and leucocyte contamination.

Adult

Catechol O-methyltransferase in red blood cells of schizophrenic, depressed, and normal human subjects.

Catechol O-methyltransferase of lysed human red blood cells was assayed under optimal conditions, using saturating concentrations of the substrates, S-adenosyl-L-methionine and 3-4-dihydroxybenzoic acid. The mean enzyme activity found in 24 normal subjects was 29-2 nmol/hr/ml RBC. The mean activity in blood of 33 female unipolar depressives was not significantly different from normal. However, higher enzyme activities were observed in the blood of 11 schizophrenic patients (38-9 nmol/hr/ml RBC). Partially purified enzyme preparations from blood of normal and schizophrenic individuals were indistinguishable with respect to substrate specificities, isoelectric pH values, and ratios of the two O-methylated products. Therefore it is unlikely that any defect in O-methylation which may occur in schizophrenia can be attributed to a change in the intrinsic properties of erythrocyte catechol O-methyltransferase.

Adult