Cellular cofactors affecting hepatitis C virus infection and replication

Recently identified hepatitis C virus (HCV) isolates that are infectious in cell culture provide a genetic system to evaluate the significance of virus-host interactions for HCV replication. We have completed a systematic RNAi screen wherein siRNAs were designed that target 62 host genes encoding proteins that physically interact with HCV RNA or proteins or belong to cellular pathways thought to modulate HCV infection. This includes 10 host proteins that we identify in this study to bind HCV NS5A. siRNAs that target 26 of these host genes alter infectious HCV production >3-fold. Included in this set of 26 were siRNAs that target Dicer, a principal component of the RNAi silencing pathway. Contrary to the hypothesis that RNAi is an antiviral pathway in mammals, as has been reported for subgenomic HCV replicons, siRNAs that target Dicer inhibited HCV replication. Furthermore, siRNAs that target several other components of the RNAi pathway also inhibit HCV replication. MicroRNA profiling of human liver, human hepatoma Huh-7.5 cells, and Huh-7.5 cells that harbor replicating HCV demonstrated that miR-122 is the predominant microRNA in each environment. miR-122 has been previously implicated in positively regulating the replication of HCV genotype 1 replicons. We find that 2'-O-methyl antisense oligonucleotide depletion of miR-122 also inhibits HCV genotype 2a replication and infectious virus production. Our data define 26 host genes that modulate HCV infection and indicate that the requirement for functional RNAi for HCV replication is dominant over any antiviral activity this pathway may exert against HCV.     

Profiling of levoamphetamine and related substances in dexamphetamine sulfate by capillary electrophoresis

A capillary electrophoresis method for the simultaneous determination of the enantiomeric purity of dexamphetamine as well as the analysis of 1R,2S-(−)-norephedrine and 1S,2S-(+)-norpseudoephedrine as potential impurities has been developed and validated. Heptakis-(2,3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin was chosen as chiral selector upon a screening of neutral and charged cyclodextrin derivatives. Separation of the analytes was achieved in a fused-silica capillary at 20 °C using an applied voltage of 25 kV. The optimized background electrolyte consisted of a 0.1 M sodium phosphate buffer, pH 2.5, containing 10 mg/ml of the cyclodextrin. The assay was linear in the range of 0.06–5.0% of the impurities based on a concentration of 2.0 mg/ml dexamphetamine sulfate in the sample solution. Analysis of commercial dexamphetamine sulfate samples revealed the presence of 3–4% of levoamphetamine while norephedrine or norpseudoephedrine could not be detected, indicating that the compound was prepared by fractionated crystallization of racemic amphetamine. Comparison with polarimetric measurements indicated that dexamphetamine with an enantiomeric excess as low as 80% still passes the pharmacopeial test of specific rotation while an amount of 0.06% of levoamphetamine can be detected by capillary electrophoresis.     

Die konservative Therapie der arteriellen Verschlusskrankheit

Conservative therapy of peripheral arterial occlusive disease aims at improving claudication and reducing overall cardiovascular risk. It therefore consists of the control and modification of known arteriosclerotic risk factors (hypertension, diabetes, smoking, hypercholesterinemia), platelet aggregation inhibition, and the application of specific drugs (e.g. cilostazol) and systematic walking programmes.     

Integral calculus problem solving: an fMRI investigation

Only a subset of adults acquires specific advanced mathematical skills, such as integral calculus. The representation of more sophisticated mathematical concepts probably evolved from basic number systems; however its neuroanatomical basis is still unknown. Using fMRI, we investigated the neural basis of integral calculus while healthy participants were engaged in an integration verification task. Solving integrals activated a left-lateralized cortical network including the horizontal intraparietal sulcus, posterior superior parietal lobe, posterior cingulate gyrus, and dorsolateral prefrontal cortex. Our results indicate that solving of more abstract and sophisticated mathematical facts, such as calculus integrals, elicits a pattern of brain activation similar to the cortical network engaged in basic numeric comparison, quantity manipulation, and arithmetic problem solving.     

Mid-trimester loss--appraisal of a screening protocol

The main causes for mid-trimester loss are known. There is likely to be overlap with those of first trimester loss, but the proportions may be different. We wished to perform an aetiological survey in a large population of patients with a history of recurrent miscarriage, for possible explanations for their second trimester miscarriages. Database analysis of 636 patients attending a UK University Teaching Hospital dedicated miscarriage clinic between 1991 and 1996 revealed a 25% prevalence (n = 158) for second trimester miscarriage. Results from an investigative screening protocol were positive in 50% of cases: 33% (n = 52) tested positive for antiphospholipid syndrome (APS); 8% (n = 13) fulfilled strict criteria for cervical incompetence; there was a 4% prevalence of uterine anomaly; 3% for infection (n = 5) and 2% of patients (n = 3) proved to be hypothyroid. Importantly, dual pathology was found in 5% of patients with a history of second trimester miscarriage. As idiopathic mid-trimester loss is a diagnosis by exclusion, a high index of suspicion is required, as are modern diagnostic techniques.