Three-dimensional human pattern visual evoked potentials. II. Multiple sclerosis patients.

Pattern visual evoked potentials were obtained from 46 patients with definite relapsing/remitting multiple sclerosis, using both a conventional 5-channel occipital array and a 3-D recording technique consisting of three bipolar derivations approximating the three dimensions of space. These three orthogonal wave forms were displayed as a 3-D Lissajous trajectory for each subject. Two of the 15 patients with completely normal conventional pattern VEPs had abnormalities of the orientation of the B-C curvilinear segment of the 3-D pattern VEPs. Delays in the first major occipital positive component (P100) were evident using both techniques; the correlation between P100 latency and the latency of the corresponding trajectory apex was r = 0.99 (P less than 0.01). Post-chiasmal MRI abnormalities were associated with 3-D VEP orientation abnormalities. Three-dimensional pattern VEPs are moderately more sensitive than conventional pattern VEPs at detecting dysfunction posterior to the optic chiasm in demyelinating disease and do not require the use of eccentric fixation to do so.     

Determination of hepatitis C virus genotype by Pyrosequencing

A simple sequencing-based assay is described for genotyping of hepatitis C virus (HCV). RT-PCR was employed to amplify a 237-nucleotide-long fragment from the 5' untranslated region (UTR) of the genome using one biotinylated and one normal primer. Subsequent to capture of the PCR products on streptavidin-coated beads, single-stranded DNA separation, and hybridization of sequencing primer, Pyrosequencing was performed. The genotype of 98 samples out of which 77 samples were from American veterans and 21 samples were from Iran was determined. The samples from the American veterans contained six different subtypes, while five subtypes were found in Iranian samples. For rapid population-specific HCV subtyping, a multiplex assay was developed. This study demonstrates the suitability of this technology for low-cost, high throughput and accurate microbial genotyping.     

A-kinase anchoring proteins in amygdala are involved in auditory fear memory

A-kinase anchoring proteins (AKAPs) constitute a family of scaffolding proteins that bind the regulatory subunits of protein kinase A (PKA). AKAP binding to PKA regulates the phosphorylation of various proteins, some of which have been implicated in synaptic plasticity and memory consolidation. Here we show that the regulatory subunits of PKA are colocalized with AKAP150 (an AKAP isoform that is expressed in the brain) in the lateral amygdala (LA) and that infusion to the LA of the peptide St-Ht31, which blocks PKA anchoring onto AKAPs, impairs memory consolidation of auditory fear conditioning.     

Role of heparan sulphate proteoglycans as potential receptors for non-piliated Pseudomonas aeruginosa adherence to non-polarised airway epithelial cells

Tight junctions seal polarised surface epithelial respiratory cells so as to prevent the passage of bacteria and toxins through the epithelial sheet. Disruption of tight junctions, which may occur during injury and repair processes of airway epithelium, favours potential bacterial interaction with receptors from cell basolateral membranes. Earlier studies reported that non-polarised and untight epithelial respiratory cells are highly susceptible to Pseudomonas aeruginosa adherence and internalisation. As heparan sulphate proteoglycans (HSP) from cell basolateral membranes in epithelial cells without tight junctions may become accessible to bacterial ligands, the present study investigated their role as potential receptors for non-piliate P. aeruginosa ligands. Treatment of cells with heparitinase I and II significantly reduced (51.2% and 51.7%, respectively) P. aeruginosa adherence to epithelial respiratory cells without tight junctions. The internalisation of bacteria was not affected by treatment with heparitinases. Treatment of the bacteria with heparin and heparan sulphate also significantly reduced their adherence to respiratory cells (34.3% and 43.7%, respectively). Treatment of cells with other enzymes (trypsin, lipase and chondroitinase ABC) or treatment of bacteria with chondroitin-4-sulphate did not modify the adherence to respiratory cells significantly. Both affinity chromatography and Western blotting assays showed the interaction of different P. aeruginosa outer-membrane proteins (OMPs) with heparin. Several bacterial strains showed differences in their profile of heparin-binding OMPs, but all exhibited low mol. wt (< 30 kDa) reactive proteins. Reactivity of whole bacterial cells with heparin was also observed by transmission electron microscopy. These results suggest that HSP are potential receptors for P. aeruginosa adherence to non-polarised and untight epithelial respiratory cells.