Exploring anterograde memory: a volumetric MRI study in patients with mild cognitive impairment.

BACKGROUND: The aim of this volumetric study was to explore the neuroanatomical correlates of the Free and Cued Selective Reminding Test (FCSRT) and the Delayed Matching-to-Sample-48 items (DMS-48), two tests widely used in France to assess verbal and visual anterograde memory. We wanted to determine to what extent the two tests rely on the medial temporal lobe, and could therefore be predictive of Alzheimer's disease, in which pathological changes typically start in this region. METHODS: We analysed data from a cohort of 138 patients with mild cognitive impairment participating in a longitudinal multicentre clinical research study. Verbal memory was assessed using the FCSRT and visual recognition memory was evaluated using the DMS-48. Performances on these two tests were correlated to local grey matter atrophy via structural MRI using voxel-based morphometry. RESULTS: Our results confirm the existence of a positive correlation between the volume of the medial temporal lobe and the performance on the FCSRT, prominently on the left, and the performance on the DMS-48, on the right, for the whole group of patients (family-wise error, P < 0.05). Interestingly, this region remained implicated only in the subgroup of patients who had deficient scores on the cued recall of the FCSRT, whereas the free recall was associated with prefrontal aspects. For the DMS-48, it was only implicated for the group of patients whose performances declined between the immediate and delayed trial. Conversely, temporo-parietal cortices were implicated when no decline was observed. Within the medial temporal lobe, the parahippocampal gyrus was prominently involved for the FCSRT and the immediate trial of the DMS-48, whereas the hippocampus was solely involved for the delayed trial of the DMS-48. CONCLUSIONS: The two tests are able to detect an amnestic profile of the medial temporal type, under the condition that the scores remain deficient after the cued recall of the FCSRT or decline on the delayed recognition trial of the DMS-48. Strategic retrieval as well as perceptual/attentional processes, supported by prefrontal and temporo-parietal cortices, were also found to have an impact on the performances. Finally, the implication of the hippocampus appears time dependent, triggered by a longer delay than the parahippocampus, rather than determined by the sense of recollection or the encoding strength associated with the memory trace.

Rotational Spectrum of CBr by Kinetic Microwave Spectroscopy of 193-nm Photolysis Products of Bromoform.

We have measured the first millimeter-wave spectrum of CBr. The radical was produced by pulsed UV-laser photolysis of bromoform at 193 nm and detected using kinetic spectroscopy. We have significantly improved the rotational and fine structure constants for the ground vibrational state. The hyperfine structure due to the bromine nucleus has been resolved and quadrupole and magnetic hyperfine parameters evaluated for the first time. Copyright 2000 Academic Press.

[Subacute distal motor neuropathy disclosing malignant non-Hodgkin lymphoma: improvement under chemotherapy]. / Neuropathie motrice distale subaiguë révélatrice d'un lymphome malin non Hodgkinien: amélioration sous chimiothérapie.

A non Hodgkin's lymphoma strictly located in the bone marrow, was discovered in a patient presenting with asymetric muscle weakness of upper and lower limbs. Both the lymphoma and the neurological syndrome were successfully treated with chemotherapy.

[In vitro study of various ionophore antibiotics and some of their derivatives. II. Characterization of the ionophore properties of the compounds in a model system for Na+ and K+ ions]. / Etude "in vitro" de quelques antibiotiques ionophores et de certains de leurs dérivés. II. Caractérisation des propriétés ionophores des composés dans un système modèle, pour les ions Na+ et K+.

Transport of Na+ and K+ by different carboxylic polyether antibiotics and some of their derivatives was measured in a triphasic water/chloroform/water model system. Monensin, nigericin, narasin and lasalocid proved to be efficient K+ carriers, while grisorixin, alborixin and X 14547A gave lower ionic fluxes. Furthermore, the structural modifications of nigericin, grisorixin and lasalocid reduced the ionophore properties of the corresponding natural metabolite. Monensin was also characterized as a good Na+ carrier. Cation transport results were in keeping with those of a previous study on the end-products of rumen fermentation. In both cases monensin, nigericin, narasin and lasalocid were the most efficient compounds.

[In vitro study of ionophore antibiotics and various derivatives. I. Action on fermentation products in the rumen]. / Etude "in vitro" de quelques antibiotiques ionophores et de certains dérivés. I. Action sur les produits de la fermentation dans le rumen.

An in vitro study was conducted to test the action of different ionophore antibiotics and some of their derivatives on the end-products of rumen fermentation. Nigericin and narasin, like monensin and lasalocid, increased the molar proportion of propionate in the V.F.A. mixture and decreased the proportion of acetate and especially that of butyrate. They had no action on total V.F.A. production. The effect observed with derivatives (lasalocid O-acetyl or nigericin-O-acetyl) was generally less. Gas production, chiefly methane, decreased with the addition of antibiotics. This result agrees with the stoichiometric reactions of carbohydrate fermentation in the rumen. The amount of ammonia nitrogen fixed by bacteria was generally lowered by the addition of five antibiotics (nigericin, narasin, monensin, grisorixin and lasalocid) or two derivatives (lasalocid O-acetyl and nigericin O-acetyl), indicating a decrease in bacterial synthesis. In contrast, calcimycin improved the butyrate production at the expense of propionate, and had no effect on gas composition or bacterial synthesis; X 14547 A and alborixin had only a small effect on rumen fermentations. These results, however, must be interpreted with care since the inocula used came from non-adapted sheep.

Synthetic models of deoxyribonucleic acid complexes with antimalarial compounds. 3. Forces involved in the stacking interaction between aminoquinoline and the nucleotide bases.

As an approach to the problem of the nature of the forces responsible for the stacking interactions between the aminoquinoline ring of the antimalarial chloroquine and the monomeric nucleotide bases, we have examined models in which the aromatic nucleus of the drug is linked to the nucleotide bases by a trimethylene chain. The degree of stacking of the models was determined in different conditions of solvent, pH, and temperature by hypochromism measurement in the UV. The results show that forces of the donor-acceptor type, due to the presence of a positive charge on the quinoline ring at neutral pH, do not bring an important contribution to the stacking interaction between the aminoquinoline and the nucleotide bases, while the influence of the solvent water is fundamental.

Synthetic models of DNA complexes with antimalarial compounds. 2. The problem of guanine specificity in chloroquine binding.

Stacking interactions between the aminoquinoline ring of the antimalarial chloroquine and the purine bases have been studied by preparing and examining models in which the quinoline is linked to the base by a trimethylene chain. The degree of stacking of the models which reflects the strength of the interaction was quantitatively determined in water at different temperatures by hypochromism measurement in the uv. Adenine and guanine exhibit equal affinity for the quinoline nucleus as reflected by very close hypochromism values observed for the two models at all temperatures studied.