Multiple sclerosis: Benefits of q-space imaging in evaluation of normal-appearing and periplaque white matter

Introduction

Diffusion tensor imaging (DTI) reveals white matter pathology in patients with multiple sclerosis (MS). A recent non-Gaussian diffusion imaging technique, q-space imaging (QSI), may provide several advantages over conventional MRI techniques in regard to in vivo evaluation of the disease process in patients with MS. The purpose of this study is to investigate the use of root mean square displacement (RMSD) derived from QSI data to characterize plaques, periplaque white matter (PWM), and normal-appearing white matter (NAWM) in patients with MS.

Methods

We generated apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps by using conventional DTI data from 21 MS patients; we generated RMSD maps by using QSI data from these patients. We used the Steel–Dwass test to compare the diffusion metrics of regions of interest in plaques, PWM, and NAWM.

Results

ADC differed (P < 0.05) between plaques and PWM and between plaques and NAWM. FA differed (P < 0.05) between plaques and NAWM. RMSD differed (P < 0.05) between plaques and PWM, plaques and NAWM, and PWM and NAWM.

Conclusion

RMSD values from QSI may reflect microstructural changes and white-matter damage in patients with MS with higher sensitivity than do conventional ADC and FA values.     

Sleep disturbances in highly stress reactive mice: Modeling endophenotypes of major depression

Background  

Neuronal mechanisms underlying affective disorders such as major depression (MD) are still poorly understood. By selectively breeding mice for high (HR), intermediate (IR), or low (LR) reactivity of the hypothalamic-pituitary-adrenocortical (HPA) axis, we recently established a new genetic animal model of extremes in stress reactivity (SR). Studies characterizing this SR mouse model on the behavioral, endocrine, and neurobiological levels revealed several similarities with key endophenotypes observed in MD patients. HR mice were shown to have changes in rhythmicity and sleep measures such as rapid eye movement sleep (REMS) and non-REM sleep (NREMS) as well as in slow wave activity, indicative of reduced sleep efficacy and increased REMS. In the present study we were interested in how far a detailed spectral analysis of several electroencephalogram (EEG) parameters, including relevant frequency bands, could reveal further alterations of sleep architecture in this animal model. Eight adult males of each of the three breeding lines were equipped with epidural EEG and intramuscular electromyogram (EMG) electrodes. After recovery, EEG and EMG recordings were performed for two days.     

High-pressure synthesis and structures of lanthanide germanides of LnGe5 (Ln=Ce, Pr, Nd, and Sm) isotypic with LaGe5

A series of lanthanide penta-germanides LnGe₅ (Ln=Ce, Pr, Nd and Sm) has been prepared by high-pressure (5–13 GPa) and high-temperature (500–1200 °C) reaction. CeGe₅ crystallizes in an orthorhombic unit cell (S.G. Immm (71)) with a=4.000(5) Å, b=6.192(5) Å, c=9.86(1) Å, and V=244.1(5) Å³. The new germanides are isotypic with LaGe₅ consisting of a Ge covalent network with tunnels where guest ions Ln³⁺ are situated. The network is composed of sublayers with edge-sharing Ge six-membered rings with only boat conformation. The sublayers are connected by rare eight-coordinated Ge atoms. The cell volume of the compounds systematically decreases from La to Sm compounds, except for CeGe_5, owing to the lanthanide contraction. The lattice constants of CeGe₅ are smaller than those of the Pr compound because it contains Ce⁴⁺ ions. CeGe₅ is paramagnetic above 2 K, but does not obey the Curie–Weiss law. PrGe₅ and NdGe₅ are Curie–Weiss type paramagnets with Weiss temperatures of –3.3 and –18.4 K. SmGe₅ shows an antiferromagnetic transition at 10.4 K.     

The total synthesis of dl-coriolin

The total synthesis of dl-coriolin has been accomplished via the key intermediate (5RS, 7SR) - 7 - t-butyldimethylsilyloxybicyclo[3.3.0]oct - 8 starting from 1,3 - cyclooctadiene.     

Determination of isoniazid in tablets by second-derivative ultraviolet spectrophotometry of scraped-spot solutions from thin-layer chromatography

Isoniazid in solutions of tablets was separated by thin-layer chromatography (TLC). The portion of the precoated plate carrying the isoniazid spot was cut out and the coating was scraped off into water. The isoniazid was quantified in the solution, without separation of suspended adsorbent, by second-derivative spectrophotometry, which eliminated the background in the zero-order spectra. Relative standard deviations (n = 5) were <1%. Results obtained for commercial tablets were in good agreement with those given by a liquid-chromatographic method.     

Electronic Structure of Cu(II) Complexes with N,N′-Disalicylidene-1,2-cyclohexanediamine and N,N′-Disalicylidenetrimethylenediamine

Summary.  The electronic absorption and X-ray photoelectron spectra of N,N′-disalicylidenetrimethylenediaminatocopper(II) ([Cu(saltn)]) and N,N′-disalicylidene-trans-1,2-cyclohexanediaminatocopper(II) ([Cu(salchx)]) were measured. From these results and from informations derived from MO calculations the electronic structure of the complexes was clarified. Each electronic absorption band which can be assigned to the ππ^ast; or ML/LMCT transition of [Cu(saltn)] or [Cu(salchx)] observed in the wavelength region of 450–200 nm appears at the almost same frequency as the corresponding band of N,N′-disalicylideneethylenediaminatocopper(II) ([Cu(salen)]) in solution. The LLCT bands (the intramolecular CT band between two π-electronic systems separated by saturated hydrocarbon chains such as ) also appear at nearly the same positions (ca. 245 nm) for [Cu(salchx)], [Cu(saltn)], and [Cu(salen)]. The locations of the dd transition and the intensity of the ML/LMCT transition of [Cu(saltn)] are significantly different from those of [Cu(salen)] and [Cu(salchx)]. These differences may arise from the strengths of the interaction between metal and ligand. Received August 21, 2001. Accepted (revised) October 20, 2001