Venezuelan equine encephalitis virus (VEEV) is a representative member of the New World alphaviruses. It is transmitted by mosquito vectors and causes highly debilitating disease in humans, equides and other vertebrate hosts. Despite a continuous public health threat, very few compounds with anti-VEEV activity in cell culture and in mouse models have been identified to date, and rapid development of virus resistance to some of them has been recorded. In this study, we investigated the possibility of using a modified nucleoside analog, β-D-N(4)-hydroxycytidine (NHC), as an anti-VEEV agent and defined the mechanism of its anti-VEEV activity. The results demonstrate that NHC is a very potent antiviral agent. It affects both the release of genome RNA-containing VEE virions and their infectivity. Both these antiviral activities are determined by the NHC-induced accumulation of mutations in virus-specific RNAs. The antiviral effect is most prominent when NHC is applied early in the infectious process, during amplification of negative and positive strand RNAs in the infected cells. Most importantly, only a low level resistance of VEEV to NHC can be developed, and it requires acquisition and cooperative function of more than one mutation in nsP4. These adaptive mutations are closely located in the same segment of nsP4. Our data suggest that NHC is more potent than ribavirin as an anti-VEEV agent, and likely can be used to treat other alphavirus infections.Venezuelan equine encephalitis virus (VEEV) can cause widespread epidemics among humans and domestic animals. VEEV infections result in severe meningoencephalitis and long-term sequilae. No approved therapeutics exist for treatment of VEEV infections. Our study demonstrates that N-hydroxycytidine (NHC) is a very potent anti-VEEV compound, with the EC being below 1 μM. The mechanism of NHC antiviral activity is based on induction of high mutation rates in the viral genome. Accordingly, NHC treatment affects both the rates of particle release and the particle infectivity. Most importantly, in contrast to most of the anti-alphavirus drugs that are under development, resistance of VEEV to NHC develops very inefficiently. Even low levels of resistance require acquisition of multiple mutations in the gene of VEEV-specific RNA-dependent RNA polymerase, nsP4.

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SummaryThis guideline provides a framework for the arrangement of point-of-care testing (POCT) services, previously known as near patient testing (patient self-testing not covered). POCT is defined as any analytical test performed outside the laboratory. Primary users are often non-laboratory healthcare workers. The guidance applies to units within hospitals as well as general practioner surgeries, community clinics and pharmacies. The head of the haematology laboratory or a point of care coordinator must take responsibility for all aspects of the POCT service, including quality and training. Depending on the size and nature of the POCT practice, a local POCT manager may also be required. Equipment selected should have received a successful independent performance evaluation. If an independent evaluation has not been performed the purchaser should assess the device according to the protocol in this document. POCT devices should generate results that are comparable to those of the local laboratory. An accredited external quality assessment programme and internal quality control system must be established. Manufacturers promoting POCT devices designed for non-laboratory sites, e.g. pharmacies, should undertake training and annual competency assessment, perhaps using a web-based system. A diagram to illustrate the stages for the implementation of a POCT service is illustrated.Keywords: point-of-care testing, point-of-care committee, accreditation, external quality assurance, instrument evaluation.The purpose of these guidelines is to provide a framework for the provision of appropriate local arrangements for pointof-care testing (POCT) and to protect patients and staff. The guideline provides information and suggestions for good laboratory practice and for producing reliable results, regardless of where the test is performed. POCT may be defined as any analytical test performed for a patient by a healthcare worker outside the laboratory setting. This document is an update to the British Committee for Standards in Haematology (BCSH) guideline for Near Patient Testing: haematology (England et al, 1995) and embodies the philosophy agreed by the Joint Working Group (JWG) (1999) on Quality Assurance, the national standards required for clinical pathology accreditation (Clinical Pathology Accreditation (CPA) (UK) Ltd, 2007, revised Burnett et al, 2002 and the International Standards Organisation (ISO) POCT requirements for quality and competence (International Standard organisation, ISO, 2004a). There have been several evaluations carried out on the views of general practioners (GPs) to POCT and quality control procedures (England et al, 1995;Murray & Fitzmaurice, 1998). GPs do not always find POCT a useful addition to their resources and the challenges presented by community environments may mean that it is more difficult to adequately address all quality control issues (Department of Health, 1987;Hilton et al, 1994). Other important factors for consideration are the efficacy of the procedures being undertaken, medicol...

The rate constant for phosphanylation of an aryl radical with trimethylstannyl diphenylphosphane (Me(3)SnPPh(2)) has been measured as k(phos) approximately 9 x 10(8) M(-1) s(-1). Aryl radicals derived from several axially chiral o-haloanilides are trapped by Me(3)SnPPh(2) with complete retention of axial chirality as shown by oxidation of the phosphanes to give stable, easily analyzed phosphane oxides or sulfides. Double phosphanylations of o,o'-dihaloanilides followed by treatment with H(2)O(2) or S(8) in either order give enantiomers of a mixed diphosphane oxide sulfide. Chemodivergent trapping of diastereomers of an N-(cyclohex-2-enyl)anilide anilide is observed. For one isomer, the cyclization precedes the Me(3)SnPPh(2) trapping, while for the other isomer direct trapping with Me(3)SnPPh(2) supersedes the cyclization. The products are chiral triaryl phosphanes, oxides, and sulfides that are potentially interesting ligands in asymmetric catalysis.