Urine levels of catecholamines in Greek children with obstructive sleep-disordered breathing.

INTRODUCTION: Adults with obstructive sleep apnea have increased sympathetic activity. It was hypothesized that in children with symptoms of obstructive sleep-disordered breathing (SDB), morning urine levels of catecholamines correlate with severity of nocturnal hypoxemia. METHODS: Children with snoring referred for polysomnography and controls without snoring were recruited. Morning urine norepinephrine, epinephrine, normetanephrine, and metanephrine levels were measured (ng/mg urine creatinine). RESULTS: Twelve children (age 5.2 +/- 2.3 years) with severe hypoxemia (oxygen saturation of hemoglobin-SpO2 nadir < or =86%), 20 subjects (age 6.1 +/- 2.1 years) with moderate hypoxemia (SpO2 nadir < or =90% and >86%), 22 children (age 6.6 +/- 1.5 years) with mild nocturnal hypoxemia (SpO2 nadir >90%), and 10 controls (age 7.1 +/- 2.8 years) were studied. Children with severe hypoxemia had significantly higher log-transformed norepinephrine levels (1.63 +/- 0.29) compared to those with moderate hypoxemia (1.43 +/- 0.22; P < 0.05) or compared to controls (1.39 +/- 0.31; P < 0.05). In subjects with SDB, log-transformed oxygen desaturation of hemoglobin index or SpO2 nadir predicted log-transformed norepinephrine levels after adjustment by age, gender and body mass index (r2 = 0.24; and r2 = 0.24, respectively; P < 0.01). CONCLUSIONS: Severity of nocturnal hypoxemia in children with intermittent upper airway obstruction during sleep correlates with morning urine levels of norepinephrine suggesting increased sympathetic tone.

[Acute polyradiculoneuritis and dysautonomia: contribution of assaying catecholamines and their methoxylated metabolites]. / Polyradiculonévrites aiguës et dysautonomie: pertinence du dosage des catécholamines et des dérivés méthoxylés.

Guillain-Barré syndrome is an acute demyelinating polyradiculoneuritis usually evolving with rapid, functional recovery. In severely paralysed patients, cranial nerve palsy and autonomic nervous system dysfunctions are common. Lesions of the spinal roots predominate but segmentary demyelination of peripheral nervous system reflects various clinical subtypes. Twelve patients (42,8 p. cent) had clinical dysautonomia. Ten had an increase of urinary methoxylated metabolites. Patients exempt of dysautonomia had normal biological parameters. The elevated level of urinary methoxylated metabolites is statistically correlated to clinical dysautonomia and can be used as a biological marker to monitoring demyelinating polyradiculoneuritis.

Optimal collection and storage conditions for catecholamine measurements in human plasma and urine.

Improvements in methodologies for measuring concentrations of catecholamines (CA) have led to an increasing use of these compounds as markers in the screening of patients and in long-term clinical trials. Because of the associated logistical problems, we have investigated the unresolved question of optimal conditions for sample preparation and for storage of plasma and urine samples. Results show that blood should be centrifuged within 1 h after collection; the use of a refrigerated centrifuge is not necessary. Once plasma is prepared, CA are stable for 1 day at 20 degrees C, 2 days at 4 degrees C, 1 month at -20 degrees C (or 6 months with added glutathione), and up to 1 year at -70 degrees C. CA are stable at 4 degrees C for 1 month in unpreserved urine and for 4 months in urine preserved with EDTA and sodium metabisulfite. In acidified urine, CA were nearly unchanged after 1 year at 4 and -20 degrees C.

[An improved trihydroxyindole method for the determination of urinary catecholamines]. / Verbesserte Trihydroxyindolmethode zur Bestimmung der Harnkatecholamine

Commercially available columns for ion exchange chromatography were used for the separation of catecholamines in urine. The estimation of catecholamines was performed fluorimetrically by a new trihydroxyindole method. The fluorescence of adrenaline or noradrenaline was enhanced, in comparison with other methods, by the combined application of boric acid, copper-ions, mercaptoethanol and final reacidification. The fluorophores are stable: The loss of fluorescence of adrenolutin amounted to 22% during 180 minutes, and there was no loss of noradrenolutin. For the differentiation of amines, adrenaline was oxidized at pH 2.85 and noradrenaline at pH 7. Precision, accuracy, sensitivity and specifity fulfilled the criteria of analysis. The normal values, determined in a collective of 17 healthy persons, were adrenaline (x +/- s) 44.8 +/- 16.9 nmol/24 h and noradrenaline (x +/- s) 224.0 +/- 68.0 nmol/24h. The simultaneous application of alpha-methyldopa (2 g/day) in 13 patients with primary hypertension did not disturb the fluorimetric estimation of catecholamines.