Simultaneous measurement of dopamine, serotonin, their metabolites and tryptophan in mouse brain homogenates by high-performance liquid chromatography with dual coulometric detection.

A new rapid and sensitive high-performance liquid chromatography (HPLC) method for the simultaneous determination of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine, 5-hydroxytryptamine (serotonin), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and tryptophan has been developed and applied to mouse frontal cortex, caudate nucleus and dorsal raphe assays. A dual coulometric detector was used with detection at +0.25 and +0.55 V, which allowed the determination of tryptophan. Detection limits for all compounds (0.8-9.0 pg per injection, depending on the compounds) were useful for this application. Owing to great sensitivity of the method, the brain tissue samples can be very small, less than 2 mg. Linearity of standards was excellent (r > 0.999 in all cases). Intraday and interday precisions for samples analytes were generally acceptable (intraday assay CV < 8.7% and interday assay CV < 7.0% except for DOPAC and 5-HIAA, which was 11.4% for the low concentrations). Average recoveries of standard additions to sample analytes were > 90%. Attention was paid to stability of standard and sample analytes when stored at +4 degrees C or at -70 degrees C with two different homogenizing agents (0.1 M HClO4 with 10(-7) M ascorbic acid and 0.05 M HClO4 without ascorbic acid). This simple, rapid and efficient method can be used as a basic research tool for modification of brain neurotransmitters in experimental pharmacological protocols for following psychotropic drug treatments in animals.

Determination of fluoxetine and its metabolite norfluoxetine in serum and brain areas using high-performance liquid chromatography with ultraviolet detection.

A high-performance liquid chromatography (HPLC) method using only 0.1 ml of serum or homogenate from brain areas has been developed for the determination of fluoxetine (FLU) and its metabolite, norfluoxetine (N-FLU), with ultraviolet detection at 227 nm. The small volume of sample required in this method allows studies in small animals, such as mouse. The method provides recoveries of up to 90% for both compounds. Acceptable coefficients of variation were found for both within-run and day-to-day assays. The limit of detection was 5.0 ng/ml. No interferences were found with tricyclic antidepressant drugs and benzodiazepines, which allows this method to be used in clinical studies, Pharmacokinetic parameters for the two compounds are reported in mouse serum, frontal cortex and caudate nucleus. We also report the values of FLU and N-FLU in serum from humans who were treated once daily with 20 mg of FLU, obtained after 1, 14 and 28 days of treatment.

Time course of troponin I, myoglobulin, and cardiac enzyme release after electrical cardioversion.

The results of this study, conducted in 25 patients without myocardial infarction, showed that all the biologic markers of myocardial infarction, except the highly cardiospecific cardiac troponin I, increased in some patients after electrical cardioversion. These results allow us to conclude that electrical cardioversion, even preceded by a mechanical resuscitation of short duration, does not result in myocardial damage, and that cardiac troponin I is more accurate than creatine kinase-MB activity and creatine kinase-MB mass determination for the diagnosis of myocardial damage in patients who have undergone electrical cardioversion.

[Validity of immunochemical assays for blood estradiol. Study conducted in 1994]. / Validité des dosages immunochimiques de l'estradiol sanguin. Etude réalisée en 1994.

Since 1989 many kits have been commercialized for measuring estradiol by non-isotopic immunoassays which largely contributed to the diffusion of this parameter. Rapidly, in quality control schemes, a wide dispersion of results has been observed. In this paper, the kits' characteristics (precision, accuracy and detection limit) have been studied and compared to a reference method (gas chromatography-mass spectrometry). In addition, estradiol determinations in patients with various pathophysiological situations have been performed to underline the difficulties of interpretation of this analyte when clinicians compare results given by the different kits. This work demonstrates that precision and accuracy varied both with the kit and the level of concentration of estradiol and gives better results for high concentrations of estradiol. In seven out of the 12 kits, the limits of detection are in good agreement with those announced by manufacturers. On the contrary, the determination on patients sera gives results with a high variability with no systematic error.