Search

Background Both traditional and atypical antipsychotics have been hypothesised to be effective in schizophrenia through fimbic and cortical D2 dopamine receptor blockade. Aims To investigate this hypothesis with the D2/D3-selective positron emission tomography (PET) probe [76Br]-FLB457. Method PET scans were performed on 6 controls and 18 patients with schizophrenia treated with haloperidol or with risperidone, clozapine, amisulpride or olanzapine. Results The D2 dopamine receptor blockade was high in the temporal cortex with both haloperidol and atypical antipsychotics. The a typicals, however, induced a significantly lower D2 binding index than haloperidol in the thalamus and in the striatum. Conclusions Results suggest that cortical D2 dopamine receptors are a common target of traditional and atypical antipsychotics for therapeutic action. Higher in vivo binding to the D2 receptors in the cortex than in the basal ganglia is suggested as an indicator of favourable profile for a putative antipsychotic compound. [ABSTRACT FROM AUTHOR]

The presence of “geological” amber (or “succin” in old French monographs) has been reported for several centuries in the Mesozoic deposits of Provence, southeastern France. Diverse amber-bearing sites were inventoried by the authors but their location and stratigraphical context remain unclear for most of them. In the past decades, various data concerning chemistry, palaeontological content and comparison with archaeological discoveries improved our knowledge of the ambers of Provence, but only those of Cretaceous age. The present paper aims at providing a comprehensive description of all the presently known amber-bearing deposits of Provence, including the description of new sites. We highlight the great potential of Provence ambers and allow to consider a wider time range, from the Early Cretaceous to the Miocene.

The Upper Cretaceous sedimentary succession cropping out in the Sainte-Baume Massif (Var, southeastern France) is of late Turonian to Campanian age. There, complex imbrication and rapid evolution in space and time of shallow-marine, fluvio-deltaic and lacustrine environments at the front of the North Provence Durancian uplift occur during the Santonian. Marly and/or sandy strata rich in lignite remains and amber grains are interspersed throughout the Santonian series. According to new in situ collections, the features of the amber grains, and their micro-inclusions, are similar to those found in well-known amber-bearing sites from the Bouches-du-Rhône department. This testifies of a widespread resin-producing tree forests in southeastern France at that time.

The measurement of cerebral blood flow (CBF) by continuous CO inhalation has only been validated previously by indirect experimental protocols. In the present study using baboons, these measurements were compared directly with those obtained by injection of Ga-labelled serum-albumin microspheres in the left cardiac ventricle. Using a modified labelling technique, no elution of Ga occurred in vivo. Both methods provided similar regional CBF values, which could be described by a significant linear correlation ( $$CBF_{CO_2 }$$ =0.82 CBF+5.7; P<0.001). The validity of the labelled-microsphere-injection method was verified. The feasibility of stable in vivo labelling of Ga to serum-albumin microspheres provides a reference method for organ blood-flow measurements using positron-emission tomography. [ABSTRACT FROM AUTHOR]

Using PET, we investigated the potency in six patients of therapeutic doses of neuroleptic drugs for preventing specific binding of trace doses of intravenously administered 76Br-labelled bromospiperone to corpus striatum in vivo. Measured receptor occupancy showed a clear-cut dose-dependent saturation curve with increasing daily oral dose of neuroleptics, indicating the validity and reliability of the method when used as an in vivo radioreceptor assay. Following drug withdrawal in eight patients, recovery to normal or supranormal receptor availability occurred in a matter of days. The results demonstrate an approach that may help resolve controversies about, and design better strategies for, neuroleptic treatment schedules. [ABSTRACT FROM AUTHOR]