Simultaneous liquid-chromatographic determination of 3,4-dihydroxyphenylglycol, catecholamines, and 3,4-dihydroxyphenylalanine in plasma, and their responses to inhibition of monoamine oxidase.

Eisenhofer, Graeme; Goldstein, David S.; Stull, Robin; Keiser, Harry R.; Sunderland, Trey; Murphy, Dennis L.; Kopin, Irwin J.

doi:10.1093/clinchem/32.11.2030

Cited by 462 publications

(109 citation statements)

References 17 publications

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“…The same authors also reported on a preliminary human experiment, where 40 mg of cimoxatone, a reversible MAO-A inhibitor, reduced plasma DHPG levels by 75%, whereas plasma DHPG was unaltered after 5 days' treatment with deprenyl 10 mg daily (Brown & Monks, 1984). On the other hand, chronic treatment of elderly humans with larger doses of deprenyl (30-60 mg/day) has been reported to reduce plasma DHPG levels by 70%, a decrement comparable with that seen after treatment with tranylcypromine (75%), a non-selective MAO inhibitor (Eisenhofer et al, 1986). This may reflect loss of MAO-B selectivity for higher doses of deprenyl upon repeated administration Sunderland etal., 1987), or alternatively, a more complex relationship between the pharmacological effects of deprenyl and plasma DHPG levels (Liebowitz et al, 1985).…”

Section: Discussionmentioning

confidence: 93%

Inhibition of monoamine oxidase by moclobemide: effects on monoamine metabolism and secretion of anterior pituitary hormones and cortisol in healthy volunteers.

Koulu

Scheinin

Kaarttinen

et al. 1989

Brit J Clinical Pharma

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1. Single oral doses (100, 200 and 300 mg) of moclobemide, a reversible inhibitor of monoamine oxidase (MAO) with predominant effects on the A‐ type of the enzyme, were administered to eight young, healthy male volunteers in a double‐blind, random‐order, placebo‐controlled study. The investigation was thereafter continued in an open fashion by administering a single 10 mg dose of the MAO‐B inhibitor deprenyl to the same subjects. 2. Deamination of catecholamines was powerfully and dose‐dependently inhibited by moclobemide, as evidenced by up to 40% decreases in the urinary excretion of deaminated catecholamine metabolites, corresponding increases in the excretion of non‐ deaminated, methylated metabolites, and up to 79% average decreases in the plasma concentration of 3,4‐dihydroxyphenylglycol (DHPG), a deaminated metabolite of noradrenaline (NA), and up to 75% average decreases in the plasma concentrations of 3,4‐dihydroxyphenylacetic acid (DOPAC), a deaminated metabolite of dopamine. The urinary excretion of 5‐hydroxyindoleacetic acid (5‐HIAA) was only slightly reduced. In contrast, deprenyl, in a dose which almost totally inhibited MAO‐B activity in blood platelets, did not appreciably affect the plasma concentrations of DHPG or DOPAC. 3. Due to the rapid, reversible, dose‐dependent and MAO‐A specific effect of moclobemide on plasma concentrations of DHPG, it is suggested that DHPG in plasma may be a useful indicator of the magnitude and duration of MAO‐A inhibition in man. 4. Sympatho‐adrenal function at rest was not significantly altered by moclobemide, as judged by unchanged plasma catecholamine concentrations and stable blood pressure and heart rate recordings. 5. Monoamine oxidase type B activity in blood platelets was slightly (less than 30%) and transiently inhibited after moclobemide. 6. The secretion of prolactin was dose‐dependently stimulated by moclobemide, whereas the plasma concentrations of growth hormone (hGH) and cortisol remained unchanged.

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Section: Discussionmentioning

confidence: 93%

Inhibition of monoamine oxidase by moclobemide: effects on monoamine metabolism and secretion of anterior pituitary hormones and cortisol in healthy volunteers.

Koulu

Scheinin

Kaarttinen

et al. 1989

Brit J Clinical Pharma

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“…Measurements of plasma-free and plasma-deconjugated normetanephrine and metanephrine concentrations were performed using liquid chromatography with electrochemical detection (LC-ECD) as described elsewhere. 20 For determination of plasma-deconjugated metanephrines 200-ll samples of plasma were incubated for 30 min at 37°C with 0Á5 units of sulphatase (Sigma, St. Louis, MO, USA). Samples of enzyme-processed plasma for measurements of deconjugated metanephrines were then subjected to the same solid-phase extraction and LC-ECD procedures as samples of plasma-free metanephrines.…”

Section: Analyses Of Metanephrinesmentioning

confidence: 99%

Plasma‐free vs deconjugated metanephrines for diagnosis of phaeochromocytoma

Pamporaki¹,

Därr²,

Bursztyn³

et al. 2013

Clinical Endocrinology

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Summary Background Diagnosis of phaeochromocytoma is commonly performed by measurements of plasma free normetanephrine and metanephrine. Plasma deconjugated normetanephrine and metanephrine have been proposed as alternative equivalent, but easier to measure biomarkers. Objective The aim of this study was to compare the diagnostic performances of plasma free versus deconjugated normetanephrine and metanephrine in patients tested for phaeochromocytoma. Methods The study population included a reference group of 262 normotensive and hypertensive volunteers, 198 patients with phaeochromocytoma and 528 patients initially suspected of having the tumour, but with negative investigations after at least 2 years of follow up. Measurements were performed using liquid chromatography with electrochemical detection. Results Median plasma concentrations of free normetanephrine were 17-fold higher in patients with phaeochromocytoma than in the reference population, a 72% larger (p<0.001) difference than that for the 10-fold higher levels of plasma deconjugated normetanephrine. In contrast, relative increases of plasma concentrations of free and deconjugated metanephrine were similar. Using upper cut-offs established in the reference population, measurements of plasma free metabolites provided superior diagnostic performance than deconjugated metabolites according to measures of both sensitivity (97% vs 92%, p=0.002) and specificity (93 vs 89%, p=0.012). The area under the receiver operating characteristic curve for the free metabolites was larger than that for the deconjugated metabolites (0.986 vs 0.965, p<0.001). Conclusion Measurements of plasma free normetanephrine and metanephrine are superior to the deconjugated metabolites for diagnosis of phaeochromocytoma.

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“…NE, E, M and NM were determined by high pressure liquid chromatography with electrochemical detection (HPLC-ED). 25,26 VMA was assayed by a spectrophotometric method. 27…”

Section: Catecholamine Studiesmentioning

confidence: 99%

Very early detection of RET proto‐oncogene mutation is crucial for preventive thyroidectomy in multiple endocrine neoplasia type 2 children

Sansó

Domene

Rudaz

et al. 2002

Cancer

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Population balance equations have been used to model a wide range of processes including polymerization, crystallization, cloud formation, and cell dynamics. Rather than developing new algorithms specific to population balance equations, it is proposed to adapt the high‐resolution finite volume methods developed for compressible gas dynamics, which have been applied to aerodynamics, astrophysics, detonation waves, and related fields where shock waves occur. High‐resolution algorithms are presented for simulating multidimensional population balance equations with nucleation and size‐dependent growth rates. For sharp distributions, these high‐resolution algorithms can achieve improved numerical accuracy with orders‐of‐magnitude lower computational cost than other finite difference and finite volume algorithms. The algorithms are implemented in the ParticleSolver software package, which is applied to batch and continuous processes with one and multiple internal coordinates. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2738–2749, 2004

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Simultaneous liquid-chromatographic determination of 3,4-dihydroxyphenylglycol, catecholamines, and 3,4-dihydroxyphenylalanine in plasma, and their responses to inhibition of monoamine oxidase.

Cited by 462 publications

References 17 publications

Inhibition of monoamine oxidase by moclobemide: effects on monoamine metabolism and secretion of anterior pituitary hormones and cortisol in healthy volunteers.

Inhibition of monoamine oxidase by moclobemide: effects on monoamine metabolism and secretion of anterior pituitary hormones and cortisol in healthy volunteers.

Plasma‐free vs deconjugated metanephrines for diagnosis of phaeochromocytoma

Very early detection of RET proto‐oncogene mutation is crucial for preventive thyroidectomy in multiple endocrine neoplasia type 2 children

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