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The aim of the present study was to investigate the effect of second-generation antipsychotics (clozapine or another second-generation antipsychotic) on perceptual abnormalities related to sensory gating deficit. Although clozapine is known to improve sensory gating assessed neurophysiologically, we hypothesized that patients with schizophrenia treated with clozapine would report less perceptual abnormalities related to sensory gating deficit than patients treated with other second-generation antipsychotics do. Forty patients with a diagnosis of schizophrenia were investigated (10 patients treated with clozapine and 30 patients treated with another second-generation antipsychotic drug). Perceptual abnormalities were assessed with the Sensory Gating Inventory. Sensory gating was assessed through electroencephalogram with the auditory event-related potential method by measuring P50 amplitude changes in a dual click conditioning-testing procedure. Patients treated with clozapine present normal sensory gating and report less perceptual abnormalities related to sensory gating than patients treated with other second-generation antipsychotics do. Although the cross-sectional design of this study is limited because causal inferences cannot be clearly concluded, the present study suggests clinical and neurophysiological advantages of clozapine compared with other second-generation antipsychotics and provides a basis for future investigations on the effect of this treatment on perceptual abnormalities related to sensory gating deficit in patients with schizophrenia.

Le neuroenhancementest un concept anglo-saxon qui concerne la prise de psychotropes psychostimulants par des sujets sains en dehors d’une indication médicale établie ou d’un contexte festif, afin d’obtenir une amélioration éventuelle du fonctionnement mental et cérébral. En 2009, devant l’augmentation aux États-Unis des demandes de neuroenhancement, l’Association américaine de neurologie a publié des recommandations pratiques déclarant qu’ « il est éthiquement acceptable de prescrire des neuroenhancers» si un certain nombre de conditions est respecté. Nous présentons ces conditions éthiques et psychopharmacologiques (« le principe de la courbe en U inversé » des performances cognitives en fonction des taux de catécholamines et « le principe de compromis » de l’amélioration cognitive) à travers un cas clinique de prescription de méthylphénidate chez un étudiant en médecine de 24 ans et sans pathologie, préparant l’examen classant national. Nous discutons ensuite le contexte éthique anglo-saxon dans lequel se situent ces recommandations.

Lemaire L, Fournier J, Ponthus C, et al. Magnetic resonance imaging of the neuroprotective effect of xaliproden in rats. Invest Radiol 2002;37321–327.

Cerebral metabolism in six children with X‐linked adrenoleukodystrophy (X‐ALD) was studied using 1H magnetic resonance spectroscopy (MRS), and the status of the patients was monitored for evaluating disease progression. Spectra were abnormal even in patients with no cerebral impairment. Four different metabolic patterns were identified, and a metabolic classification of the disease was proposed, from grade 0 to grade III. The evolution of the disease toward grade II appears to be systematic, but many patients did not evolve from this grade to grade III, which is the metabolic mark of severe progressive forms. Metabolic data of X‐ALD were processed using discriminant analysis, which provides a classification accuracy of 95.2%. Proton cerebral MRS together with discriminant analysis may be useful during the follow‐up in X‐ALD for monitoring the evolution of the disease and the effects of therapy. Magn Reson Med 41:1119–1126, 1999. © 1999 Wiley‐Liss, Inc.

Cerebral metabolism in six children with X-linked adrenoleukodystrophy (X-ALD) was studied using ¹H magnetic resonance spectroscopy (MRS), and the status of the patients was monitored for evaluating disease progression. Spectra were abnormal even in patients with no cerebral impairment. Four different metabolic patterns were identified, and a metabolic classification of the disease was proposed, from grade 0 to grade III. The evolution of the disease toward grade II appears to be systematic, but many patients did not evolve from this grade to grade III, which is the metabolic mark of severe progressive forms. Metabolic data of X-ALD were processed using discriminant analysis, which provides a classification accuracy of 95.2%. Proton cerebral MRS together with discriminant analysis may be useful during the follow-up in X-ALD for monitoring the evolution of the disease and the effects of therapy. Magn Reson Med 41:1119–1126, 1999. © 1999 Wiley-Liss, Inc.

The aim of this study is to evaluate comparatively the metabolic information afforded by proton magnetic resonance (MR) spectroscopy with stimulated-echo acquisition mode (STEAM) (echo time [TE], 20 mseconds) and point-resolved spectroscopy sequence(PRESS) (TE, 135 mseconds) spectra in HIV-related encephalopathy.

□ Small unilamellar liposomes containing fluorinated steroids (flumethasone and dexamethasone) were obtained. A physicochemical evaluation was conducted based on photon correlation spectroscopy (PCS) and fluorine-19 (19F) nuclear magnetic resonance (NMR) spectroscopy compared with standard biochemical methods (HPLC). The PCS method provides a fast and adequate evaluation of some critical features of liposomes (size, physical stability). In addition, 19F NMR spectroscopy gives substantial information, in a nondestructive manner, on steroid behavior in the membrane upon encapsulation and also when the temperature of liposomes is increased. The combined spectroscopic approach proposed here might prove useful in (1) the management of liposomal formulation, especially in the documentation of physicochemical properties, (2) pharmaceutical control in the industrial production line, and (3) control preceding injection at the clinical site. Spectroscopic techniques might offer a complementary approach to classical biochemical methods in the evaluation of the properties of a liposomal formulation and could be usefully integrated into quality control procedures.

Twenty children older than 2 y infected with human immunodeficiency virus (HIV) were examined by in vivo proton magnetic resonance spectroscopy (1H MRS) to study their cerebral metabolism and to identify metabolic profiles in relation with different stages of the disease. Patients were rated regarding their clinical and immunologic status according to the Centers for Disease Control classification and were divided into two groups: without encephalopathy (E-, n = 15) and with progressive encephalopathy (E+, n = 5). The acquisition was performed in the centrum semiovale using the short echo stimulated echo acquisition mode 20-ms sequence. The MRS profile was abnormal in all HIV-infected children compared with healthy age-matched controls (n = 7), even when magnetic resonance images were normal. A significant increase of the proportion of the lipid signals (ANOVA, p < 0.05) was found in all HIV-infected children. In addition, a significant decrease of the proportion of the N-acetylaspartate signal and a significant increase of the proportion of the myo-inositol signal (ANOVA, p < 0.05) characterized the E+group. The principal component analysis performed on eight variables on 30 spectra confirms that the spectra of HIV-infected children differ from control spectra. The E+group and the E-group are clearly separated on the map of subjects on the principal plane. The E-group lies in an intermediate position between the E+group and the control group. The evolution of metabolic alterations in the brain of HIV-infected children can clearly be monitored by 1H MRS and associated with the occurrence of an encephalopathy.

The impact of induced lipolysis on the composition of plasma lipids is analyzed by proton magnetic resonance spectroscopy (MRS) in humans. The variations of the methylene and methyl resonances from lipids in lipoproteins are studied under two sets of lipolytic conditions: acute endovascular lipolysis induced by an intravenous injection of heparin and subacute lipolysis induced by short fasting. During acute lipolysis, the degradation of the very low density lipoproteins structures is well correlated to the modifications observed in the areas of CH2 and CH3 MRS signals. The comparison of regular spectra, spectra with water signal suppression, and spectra recorded with a spin-echo sequence provides information on the behavior of the different parts of the lipoproteins, that is, the neutral core, little affected by heparine-induced lipoprotein lipase (LPL) activation, and the surface layer supplying substrates to LPL. During 48 h of fasting, only limited modifications occur on the MR spectra, and lipolysis cannot be documented in details.