Determination of platelet monoamine oxidase activity in human platelet-rich plasma— A new microfluorescent assay utilizing kynuramine as substrate

McEntire, John E.; Buchok, Stephen J.; Papermaster, Ben W.

doi:10.1016/0006-2952(79)90698-1

Cited by 16 publications

(4 citation statements)

References 7 publications

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“…To our knowledge, this is the first study to report Km and Vmax of platelet MAO in PMS. Previously, it has been reported that, using kynuramine, the Km and Vmax of platelet MAO in normal volunteers was 30 \iM and 10.9 nmol 4-hydroxyquinoline/108 platelets/h, respectively [McEntire et al, 1979], This is similar to our findings in control patients, al though the Vmax in our study was lower, which could be ascribed to methodological differences, such as prepara tion of PRP and pH of assay buffer.…”

Section: Discussionsupporting

confidence: 89%

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Effect of Plasma from Premenstrual Syndrome and Control Patients on Human Platelet and Rat Brain Synaptosome Monoamine Oxidase B Activity

Ashby

Carr

Cook³

et al. 1992

Neuropsychobiology

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The present study determined the kinetic properties of platelet monoamine oxidase (MAO) in patients with premenstrual syndrome (PMS) and control subjects during the pre- and postmenstrual intervals. In addition, we investigated the effects of plasma obtained during the pre- and postmenstrual intervals from both subject groups on MAO activity in washed human platelets and rat brain synaptosomes. The V_max of platelet MAO in postmenstrual PMS patients was significantly less than that during the premenstrual phase. Plasma from both subject groups (10–100 µl) inhibited platelet and synaptosomal MAO in a dose-dependent manner to approximately the same degree at each time interval. The results indicate that although human plasma contains endogenous substances which inhibit MAO activity, alterations in their concentration are probably not responsible for the previously reported transient changes in platelet MAO activity in PMS.

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Section: Discussionsupporting

confidence: 89%

“…MAO activity was determined using a previously reported method [McEntire et al, 1979], Briefly. 100 pi of PRP incubated with 10 mA/ potassium phosphate buffer (pH 7.4) and either 7.5.…”

Section: Mao Assaymentioning

confidence: 99%

Effect of Plasma from Premenstrual Syndrome and Control Patients on Human Platelet and Rat Brain Synaptosome Monoamine Oxidase B Activity

Ashby

Carr

Cook³

et al. 1992

Neuropsychobiology

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“…Platelet MAO activity in PRP samples was assayed with kynuramine as a substrate, by a method similar to that described by McEntire et al 39 with modifications as follows: platelet suspension (100 μL of PRP, 20 to 40 × 10 6 platelets) was preincubated (for 5 minutes at 37°C) with buffer (Na‐borate‐HCl, pH 8.3) and was then incubated with a saturating concentration of substrate (32 μM) in a final volume of 2 mL for 60 minutes. The reaction was stopped by adding trichloroacetic acid (1 mL, 30%), the mixture was centrifuged, and the formed 4‐hydroxyquinoline (4‐HQ) was measured fluorimetrically at 310 nm excitation and 362 nm emission.…”

Section: Methodsmentioning

confidence: 99%

Platelet Serotonin Measures in Migraine

et al. 2002

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“…[17] Platelet MAO activity was calculated in terms of nmol/h/mg protein. The COMT activity in erythrocytes was determined by the fluorimetric method of Axerod and Tomchick.…”

Section: Methodsmentioning

confidence: 99%

Oxidant/antioxidant status in obese adolescent females with acne vulgaris

Abulnaja

2009

Indian J Dermatol

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Background and Objectives:Acne vulgaris is a distressing skin condition, which can carry with it significant psychological disability. Oxidant/antioxidant imbalance leads to increased production of free radicals, that cause many diseases. Some nutrients, along with systemic oxidative stress, have been implicated in acne vulgaris. The goal of the present study was to assess oxidant and antioxidant status in correlation with the incidence of acne vulgaris in adolescent obese females.Materials and Methods:A total of 60 adolescent females (age 16-22 years) were divided into four groups (15 each) as follows: The first included obese females with acne; the second included obese females without acne; the third included non obese with acne and the fourth included non obese without acne. Fasting serum Malondialdehyde (MDA), β-carotene, and Vitamins A, E, and C were measured. In addition, platelet monoamineoxidase (MAO), and erythrocyte catechol-o-methyltransferase (COMT) activities were determined.Results:It was found that serum MDA was statistically significantly decreased in obese and non obese subjects with acne, as compared to those without acne (P<0.05, P<0.001) respectively. In contrast, the levels of β-carotene, vitamins A, E and C and the activity of MAO were significantly decreased in the obese and non obese with acne, as against the obese and non obese without acne.Interpretation:In obese subjects, increased fat content facilitates free radical production and lipid peroxidation, as indicated by increased MDA level, which is scavenged by the antioxidant vitamins. The decreased activity of MAO may be inhibited by free radicals and this causes psychological depression in adolescents. However there were non significant changes in the activity of COMT among the studied groups.Conclusion:The nutritional factors and a weakened antioxidant defense system may interplay, to increase the risk of psychological sequelae in acne vulgaris.

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Determination of platelet monoamine oxidase activity in human platelet-rich plasma— A new microfluorescent assay utilizing kynuramine as substrate

Cited by 16 publications

References 7 publications

Effect of Plasma from Premenstrual Syndrome and Control Patients on Human Platelet and Rat Brain Synaptosome Monoamine Oxidase B Activity

Effect of Plasma from Premenstrual Syndrome and Control Patients on Human Platelet and Rat Brain Synaptosome Monoamine Oxidase B Activity

Platelet Serotonin Measures in Migraine

Oxidant/antioxidant status in obese adolescent females with acne vulgaris

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