Effect of L-dopa loading on 5-HTP decarboxylation in rat brain areas.

The time course of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in four rat brain areas (hypothalamus, hippocampus, striatum and olfactory bulbs) were investigated after treatment with L-dopa (125 mg/kg, ip) + benserazide (50 mg/kg, ip). 5-HTP levels increased as early as 0.5 h, showed maximum accumulation at 1.5 h and returned to control levels within 4 h, while 5-HT was markedly decreased in all four structures, with a maximum effect at 1.5 h (approximately -70%) in the four areas. The decrease in 5-HT was not accompanied by changes in 5-HIAA levels. In agreement with previous studies, these data demonstrate that L-dopa loading interferes with serotonin metabolism in the rat brain. However, in addition to the releasing action of newly-synthesized dopamine, the accumulation of 5-HTP and the parallel decrease in 5-HT indicate a reduction in 5-HT synthesis. This inhibition could be explained by a competitive effect of L-dopa for aromatic aminoacid decarboxylase activity.

Levetiracetam in a broad population of patients with refractory epilepsy: interim results of the international SKATE trial.

OBJECTIVE: To prospectively assess the safety and efficacy of levetiracetam in patients with uncontrolled focal epilepsy, in a common practice-based setting. PATIENTS AND METHODS: In this phase IV, open-label, 16-week community-based study, adult patients with focal seizures initially received levetiracetam 1,000 mg/day. Throughout the study, the dose was adjusted in increments of 1,000 mg (maximum 3,000 mg/day) to achieve seizure control and maintain tolerability. The outcome parameters were the percentage reduction in partial and total seizure frequency per week from historical baseline, global evaluation scale (GES), and adverse events (AE). RESULTS: Seven hundred and thirty-one patients were included in this analysis and 84.4% completed the study. The median percent reduction in all seizures was 47.8%, and 49.3% for all partial seizures. The 50% responder rate was 49%, and the seizure-free rate was 17.2% for all partial seizures. Approximately 60% of patients showed moderate to marked improvement on the GES. The majority of AE were of mild to moderate severity; the most commonly reported being asthenia, somnolence, headache, and dizziness. CONCLUSION: Levetiracetam is both efficacious and safe as an add-on therapy in patients with refractory epilepsy treated by clinicians in their daily practice.

[Current humoral profile in acute severe asthma]. / Profil humoral actuel des asthmes aigus graves.

This study examined the relationships between acid-base disorders, hypoxemia, electrolyte imbalances, plasma adrenaline (Ad) and noradrenaline (NAd) in 94 patients with acute severe asthma. Criteria of inclusion were [PaO2 + PaCO2/.8] less than 140 mmHg when breathing air (FiO2 = 21%) and/or PaCO2 greater than or equal to 45 mmHg. PaCO2 was closely related to H+ in those patients with hypercapnia: H+ nmol/l = 0.88 PaCO2 + 4 (r 0.91 ; n = 61; p less than 0.001). However, among the 62 acidotic cases (pH less than or equal to 7.36), 24 were classified as respiratory, 22 as mixed and 16 as metabolic. A loose though highly significant relationship was found between PaO2 and PaCO2 (when breathing air). Blood lactate, which was 3.61 +/- 1.9 mmol/l (+/- SD), was not correlated with anion gap or H+, but was loosely related to PaO2 and kalemia. Ad (1.53 +/- 1.17 nmol/l) and NAd (5.85 +/- 3.44 nmol/l), measured at the time of admission in 27 patients (FIO2 = 21%), varied significantly from those of a control group (p less than 0.01). NAd was correlated with H+, lactate and especially PaCO2, whereas no correlation could be established for Ad with these factors or NAd values. On the average, kalemia, phosphatemia and calcemia were lowered. In conclusion, mixed and metabolic acidosis were more common in this study than in a previous personal series and were not necessarily associated with an increase in blood lactate. Drugs taken prior to hospitalization must be considered in the pathophysiology of hyperlactatemia, which appears to be one among several factors linked to NAd levels.