Determination and Therapeutic Exploitation of Ebola Virus Spontaneous Mutation Frequency.

UNLABELLED: Ebola virus (EBOV) is an RNA virus that can cause hemorrhagic fever with high fatality rates, and there are no approved vaccines or therapies. Typically, RNA viruses have high spontaneous mutation rates, which permit rapid adaptation to selection pressures and have other important biological consequences. However, it is unknown if filoviruses exhibit high mutation frequencies. Ultradeep sequencing and a recombinant EBOV that carries the gene encoding green fluorescent protein were used to determine the spontaneous mutation frequency of EBOV. The effects of the guanosine analogue ribavirin during EBOV infections were also assessed. Ultradeep sequencing revealed that the mutation frequency for EBOV was high and similar to those of other RNA viruses. Interestingly, significant genetic diversity was not observed in viable viruses, implying that changes were not well tolerated. We hypothesized that this could be exploited therapeutically. In vitro, the presence of ribavirin increased the error rate, and the 50% inhibitory concentration (IC50) was 27 µM. In a mouse model of ribavirin therapy given pre-EBOV exposure, ribavirin treatment corresponded with a significant delay in time to death and up to 75% survival. In mouse and monkey models of therapy given post-EBOV exposure, ribavirin treatment also delayed the time to death and increased survival. These results demonstrate that EBOV has a spontaneous mutation frequency similar to those of other RNA viruses. These data also suggest a potential for therapeutic use of ribavirin for human EBOV infections. IMPORTANCE: Ebola virus (EBOV) causes a severe hemorrhagic disease with high case fatality rates; there are no approved vaccines or therapies. We determined the spontaneous mutation frequency of EBOV, which is relevant to understanding the potential for the virus to adapt. The frequency was similar to those of other RNA viruses. Significant genetic diversity was not observed in viable viruses, implying that changes were not well tolerated. We hypothesized that this could be exploited therapeutically. Ribavirin is a viral mutagen approved for treatment of several virus infections; it is also cheap and readily available. In cell culture, we showed that ribavirin was effective at reducing production of infectious EBOV. In mouse and monkey models of therapy given post-EBOV exposure, ribavirin treatment delayed the time to death and increased survival. These data provide a better understanding of EBOV spontaneous mutation and suggest that ribavirin may have great value in the context of human disease.

Feasibility of resectoscopic operative hysteroscopy in a UK outpatient clinic using local anesthetic and traditional reusable equipment, with patient experiences and comparative cost analysis.

STUDY OBJECTIVE: To assess procedural success, patient acceptability, and cost-saving potential of operative hysteroscopy using conventional equipment and local anesthetic in an outpatient clinic. DESIGN: Feasibility study/service evaluation (Canadian Task Force classification II-3). SETTING: Outpatient (office) clinic in a large UK teaching hospital. PATIENTS: One hundred eighteen women with diagnosed or suspected intrauterine myomas or polyps. INTERVENTIONS: Operative hysteroscopy (122 monopolar resection procedures using 8- or 10-mm diameter rigid resectoscopes with glycine solution for uterine irrigation) with the patient under local anesthesia in an outpatient (office) clinic. MEASUREMENTS AND MAIN RESULTS: Procedural success, duration of procedure, pathologic measurements, glycine irrigant deficit, patient pain scores and satisfaction, and comparative costs were recorded. Success of outpatient procedures was 90% (110 of 122 attempted), with a significantly reduced median procedure duration compared with a surgical setting using local (-7 minutes; p = .009) or general (-12.5 minutes; p < .001) anesthetic. Glycine irrigant absorption was low (median deficit, 0 mL), and no deficit was observed in 81% of patients. Mean (SD) estimated disease volume was comparable to that of hysteroscopic resection procedures in a surgical setting (3.38 [5.09] cm(3)), and weight was 1.8 (1.84) g. Patients tolerated the procedure well and reported low pain scores (highest median periprocedure pain measurement was 1.25 of 10), and 7-day follow-up satisfaction responses were positive. Retrospective cost analysis demonstrated that operative resection in an outpatient clinic was less expensive than in a surgical setting using general anesthetic (-$1003) or local anaesthetic (-$234). Reduced staff costs were the primary reason for this saving. CONCLUSIONS: Operative hysteroscopic resection of myomas and polyps is feasible and well tolerated by patients in an outpatient/office setting using local anaesthetic and conventional equipment. The outpatient procedure is less expensive and its duration is shorter than in a surgical setting.

Mechanisms of phosphorus removal by cement-bound ochre pellets.

Hydrous ferric oxide (here termed 'ochre') sludge, an abundant waste product produced from the treatment of acid mine drainage (AMD), was used in this study for the removal of phosphorus (in the form of phosphate ions) from contaminated waters. The phosphorus uptake capacities of both raw and pelletized AMD solids were compared using batch and column tests. Addition of a cement binder to the AMD solids during pellet production led to significantly increased P-loading of the resultant solids compared to the raw sludge. Additionally, the pellets were found to continue to remove P in tests up to 7 d in duration whereas the unbound AMD sludge appeared to approach equilibrium with phosphate solution after approximately 60 min of contact time. In line with previous studies P uptake by the AMD solids was found to be primarily via adsorption. By contrast calcium phosphate precipitation was found to be the dominant removal mechanism for the cement-bound ochre pellets with a relatively small proportion of removal attributable to the AMD solids. SEM-EDX analysis of the surface of used pellets showed a Ca:P molar ratio close to that of hydroxyapatite (HAP). Continuous column tests on these pellets showed a rapid decrease in P removal capacity by the pellets over time, attributable to the formation of a passivating HAP surface layer.