Microdialysis of melatonin in the confluens sinuum of the rat following quantification by gas chromatography-mass spectrometry in the negative chemical ion mode.

In this study, an original surgical implantation technique in the confluens sinuum via the superior sagittal vein was developed to quantify melatonin secretion by the pineal gland. Melatonin (CAS 73-31-4) was determined using gas chromatography couples to negative ion chemical ionisation mass spectrometry following liquid extraction and derivatisation by penta-fluoropropionic acid anhydride (PFPA). The minimum detectable amount was 40 fg per injection, corresponding to 1 pg.

Blood and cerebral concentrations of the new potential analgesic UP 26-91 measured in vivo by microdialysis after toxic doses.

The concept of proportionality between the pharmacological effects of drugs and their dosage has been questioned since the discovery of saturable phenomenon for some drug dispositions, either during their absorption or their elimination. Such saturation may also occur during the distribution phase in the tissues. This phenomenon, however, is often difficult to demonstrate and microdialysis is a powerful technique to assess precise changes in drug concentrations in tissue.

The dosing-time dependent influence of chronic cyclosporin A treatment on daily profiles of plasma glucose and insulin in the Wistar rat.

The dosing-time dependent effects of cyclosporin A (CsA) on glucose and insulin plasma levels were evaluated in the light of possible alterations of their biological rhythms. Male Wistar rats weighing 200-250 g were habituated to a 12:12 h light-dark cycle. At the beginning of the experiments, on day D0 (before any treatment), significant rhythms were obtained for plasma glucose and immunoreactive insulin (IRI).

In vitro and in vivo protein binding of methotrexate assessed by microdialysis.

The purpose of the study was firstly to estimate methotrexate protein binding using microdialysis, and secondly to determine the influence of the protein content in the dialyzed medium on the dialysis membrane recovery. In vitro recovery was estimated by both water recovery method and concentration difference method. The relative recovery was independent of methotrexate concentration: 39.

Measurement of actinic erythema in healthy subjects and in subjects with polymorphous light eruption using a tristimulus colorimeter.

Background: The assessment of actinic erythema using a tristimulus colorimeter has only been reported from healthy volunteers but never from subjects with photodermatosis.

Objective: The aim of this study was to analyse the difference of chromometric measurements in patients with polymorphous light eruption versus healthy subjects.

Methods: Seventy-two subjects were subdivided according to two criteria: skin colour and clinical state.