Stereoselective Epimerizations of Glycosyl Thiols.

Glycosyl thiols are widely used in stereoselective S-glycoside synthesis. Their epimerization from 1,2-trans to 1,2-cis thiols (e.g., equatorial to axial epimerization in thioglucopyranose) was attained using TiCl4, while SnCl4 promoted their axial-to-equatorial epimerization. The method included application for stereoselective ß-d-manno- and ß-l-rhamnopyranosyl thiol formation. Complex formation explains the equatorial preference when using SnCl4, whereas TiCl4 can shift the equilibrium toward the 1,2-cis thiol via 1,3-oxathiolane formation.

Anandamide externally added to lipid vesicles containing trapped fatty acid amide hydrolase (FAAH) is readily hydrolyzed in a sterol-modulated fashion.

We show that anandamide (AEA) externally added to model membrane vesicles containing trapped fatty acid amide hydrolyase (FAAH) can be readily hydrolyzed, demonstrating facile, rapid anandamide movement across the lipid bilayer. The rate of hydrolysis is significantly facilitated by cholesterol and coprostanol, but not by cholesterol sulfate. The effects of sterol upon hydrolysis by FAAH bound to the outer surface of the bilayer were much smaller, although they followed the same pattern. We propose the facilitation of hydrolysis is a combination of the effects of sterol on accessibility of membrane-inserted endocannabinoids to surface protein, and on the rate of endocannabinod transport across the membrane bilayer.

Detection of viral RNA from paraffin-embedded tissues after prolonged formalin fixation.

BACKGROUND: Isolating amplifiable RNA from formalin-fixed, paraffin-embedded (FFPE) tissues is more difficult than isolating DNA because of RNases, chemical modification of the RNA, and cross-linking of nucleic acids and proteins. Tissues containing infectious disease agents that require biosafety level (BSL)-3 and -4 necessitate fixation times of 21 and 30 days, respectively. OBJECTIVE: To improve procedures for extracting RNA from these FFPE tissues and detect the RNA with the more sensitive TaqManbased reverse transcriptase (RT)-PCR. STUDY DESIGN: Through a single modification of a commercially available kit, we were able to extract amplifiable RNA and detect West Nile virus (WNV), Marburg virus (MARV), and Ebola virus (EBOV)-infected tissues using TaqMan assays. RESULTS: Formalin fixation results in an approximately 2log(10) reduction in detection limit when compared to fresh tissues. Increasing proteinase K digestion (24h) improved extraction of amplifiable RNA from FFPE tissues. The TaqMan results were comparable to more traditional detection results such as virus isolation. CONCLUSION: This improved extraction procedure for obtaining RNA combined with the TaqMan RT-PCR assays permit retrospective and prospective studies on FFPE tissues infected with BSL-3 and -4 pathogens.

An evaluation of screening measures for cognitive impairment after stroke.

OBJECTIVES: To assess the sensitivity and specificity of a screening battery for detecting cognitive impairment after stroke. DESIGN: A randomized controlled trial. METHODS: Stroke patients were recruited from hospitals in three centres. Patients were screened for cognitive impairment on the Mini-Mental State Examination, the Sheffield Screening Test for Acquired Language Disorders and Raven's Coloured Progressive Matrices and received a further battery of assessments of cognitive function. Sensitivity and specificity values were calculated for the three screening measures for overall conclusions regarding cognitive impairment reached from a comprehensive assessment. Receiver Operating Characteristic Curves were plotted. CONCLUSION: The Mini-Mental State Examination was not a useful screen for memory problems or overall cognitive impairment after stroke. The Sheffield Screening Test for Acquired Language Disorders was an appropriate screen for language problems. The Raven's Coloured Progressive Matrices was appropriate as a screen for perceptual problems and visual inattention but not for executive deficits.