87 research outputs found

    Identifying barriers to empowerment initiatives in a fire service command structure: An international comparison of the issues of empowerment in four fire brigades.

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    Fire brigades in the UK are currently exploring initiatives aimed at improving "Quality of Service". This has most commonly been in response to challenges presented by the "Citizens Charter", Audit Commission models for quality in service delivery, measurement of performance in service delivery, and, increasingly, budgetary pressures in brigades. Of the routes that are available towards quality improvement, Total Quality Management, or TQM is one that is gaining in popularity. It is the author's contention that as an organisation, the fire service, like the police, military and other command organisations, is subtly different to commercial, industrial, and most other public sector organisations. For this reason, not all of the models for quality improvement that are offered to the service are either useful or viable, and the resistance to them is not merely a symptom of unwillingness to change. Of the package of concepts embraced by the label TQM, one of the most problematic for the fire service has been that of empowerment. Part of the reason is that empowerment is not well defined in itself. This is not to suggest that the concept is not real, or that it is impossible to apply. There are, however, distinct difficulties with both the concept and its application in the fire service. This is an organisation founded on a hierarchical and bureaucratic structure; discipline and obedience to orders on the fireground are enshrined not only in tradition but also in formal Discipline Regulations. Additional considerations of uniform, rank and a hazardous working environment, against the backdrop of a unionised workforce, central government monitored service delivery standards and local political control, all constitute barriers to the successful implementation of empowerment. The question implicit throughout this investigation is whether empowerment of a workforce, which is structured and conditioned by experience to follow identified leaders, and to operate within strict procedural and organisational constraints, can ever succeed, and whether success would be recognised. Therefore, this dissertation centres on an investigation of the issue of "Empowerment" in the context of a command organisation, against a background of TQM. For the purposes of this investigation the concept of empowerment was examined in detail, and the following"working definition" established in the context of a disciplined command organisation: "Empowerment is about giving the authority to make quality improvements to those who have the ability to make them; this must be done within a clear framework of strategy and values, by teams which have the necessary knowledge and ability, and which are managed by well trained, inspirational leaders." (Abstract shortened by ProQuest.)

    Improved antiviral efficacy using TALEN-mediated homology directed recombination to introduce artificial primary miRNAs into DNA of hepatitis B virus

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    Chronic infection with hepatitis B virus (HBV) remains an important global health problem. Currently licensed therapies have modest curative efficacy, which is as a result of their transient effects and limited action on the viral replication intermediate comprising covalently closed circular DNA (cccDNA). Gene editing with artificial HBV-specific endonucleases and use of artificial activators of the RNA interference pathway have shown anti-HBV therapeutic promise. Although results from these gene therapies are encouraging, maximizing durable antiviral effects is important. To address this goal, a strategy that entails combining gene editing with homology-directed DNA recombination (HDR), to introduce HBV-silencing artificial primary microRNAs (pri-miRs) into HBV DNA targets, is reported here. Previously described transcription activator-like effector nucleases (TALENs) that target the core and surface sequences of HBV were used to introduce double stranded breaks in the viral DNA. Simultaneous administration of donor sequences encoding artificial promoterless anti-HBV pri-miRs, with flanking arms that were homologous to sequences adjoining the TALENs' targets, augmented antiviral efficacy. Analysis showed targeted integration and the length of the flanking homologous arms of donor DNA had a minimal effect on antiviral efficiency. These results support the notion that gene editing and silencing may be combined to effect improved inhibition of HBV gene expression.The South African Medical Research Council, Poliomyelitis Research Foundation, Johnson & Johnson Innovation, Claude Leon Foundation and South African National Research Foundation (81768, 81692, 68339, 85981 & 77954).http://www.elsevier.com/locate/ybbrc2017-09-30hb2016Haematolog

    Deriving four functional anti-HIV siRNAs from a single Pol III-generated transcript comprising two adjacent long hairpin RNA precursors

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    Several different approaches exist to generate expressed RNA interference (RNAi) precursors for multiple target inhibition, a strategy referred to as combinatorial (co)RNAi. One such approach makes use of RNA Pol III-expressed long hairpin RNAs (lhRNAs), which are processed by Dicer to generate multiple unique short interfering siRNA effectors. However, because of inefficient intracellular Dicer processing, lhRNA duplexes have been limited to generating two independent effective siRNA species. In this study, we describe a novel strategy whereby four separate anti-HIV siRNAs were generated from a single RNA Pol III-expressed transcript. Two optimized lhRNAs, each comprising two active anti-HIV siRNAs, were placed in tandem to form a double long hairpin (dlhRNA) expression cassette, which encodes four unique and effective siRNA sequences. Processing of the 3′ position lhRNA was more variable but effective multiple processing was possible by manipulating the order of the siRNA-encoding sequences. Importantly, unlike shRNAs, Pol III-expressed dlhRNAs did not compete with endogenous and exogenous microRNAs to disrupt the RNAi pathway. The versatility of expressed lhRNAs is greatly expanded and we provide a mechanism for generating transcripts with modular lhRNAs motifs that contribute to improved coRNAi

    Writing in Britain and Ireland, c. 400 to c. 800

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    The Efficacy of Generating Three Independent Anti-HIV-1 siRNAs from a Single U6 RNA Pol III-Expressed Long Hairpin RNA

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    RNA Interference (RNAi) effectors have been used to inhibit rogue RNAs in mammalian cells. However, rapidly evolving sequences such as the human immunodeficiency virus type 1 (HIV-1) require multiple targeting approaches to prevent the emergence of escape variants. Expressed long hairpin RNAs (lhRNAs) have recently been used as a strategy to produce multiple short interfering RNAs (siRNAs) targeted to highly variant sequences. We aimed to characterize the ability of expressed lhRNAs to generate independent siRNAs that silence three non-contiguous HIV-1 sites by designing lhRNAs comprising different combinations of siRNA-encoding sequences. All lhRNAs were capable of silencing individual target sequences. However, silencing efficiency together with concentrations of individual lhRNA-derived siRNAs diminished from the stem base (first position) towards the loop side of the hairpin. Silencing efficacy against HIV-1 was primarily mediated by siRNA sequences located at the base of the stem. Improvements could be made to first and second position siRNAs by adjusting spacing arrangements at their junction, but silencing of third position siRNAs remained largely ineffective. Although lhRNAs offer advantages for combinatorial RNAi, we show that good silencing efficacy across the span of the lhRNA duplex is difficult to achieve with sequences that encode more than two adjacent independent siRNAs

    Design of RNAi Hairpins for Mutation-Specific Silencing of Ataxin-7 and Correction of a SCA7 Phenotype

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    Spinocerebellar ataxia type 7 is a polyglutamine disorder caused by an expanded CAG repeat mutation that results in neurodegeneration. Since no treatment exists for this chronic disease, novel therapies such post-transcriptional RNA interference-based gene silencing are under investigation, in particular those that might enable constitutive and tissue-specific silencing, such as expressed hairpins. Given that this method of silencing can be abolished by the presence of nucleotide mismatches against the target RNA, we sought to identify expressed RNA hairpins selective for silencing the mutant ataxin-7 transcript using a linked SNP. By targeting both short and full-length tagged ataxin-7 sequences, we show that mutation-specific selectivity can be obtained with single nucleotide mismatches to the wild-type RNA target incorporated 3′ to the centre of the active strand of short hairpin RNAs. The activity of the most effective short hairpin RNA incorporating the nucleotide mismatch at position 16 was further studied in a heterozygous ataxin-7 disease model, demonstrating significantly reduced levels of toxic mutant ataxin-7 protein with decreased mutant protein aggregation and retention of normal wild-type protein in a non-aggregated diffuse cellular distribution. Allele-specific mutant ataxin7 silencing was also obtained with the use of primary microRNA mimics, the most highly effective construct also harbouring the single nucleotide mismatch at position 16, corroborating our earlier findings. Our data provide understanding of RNA interference guide strand anatomy optimised for the allele-specific silencing of a polyglutamine mutation linked SNP and give a basis for the use of allele-specific RNA interference as a viable therapeutic approach for spinocerebellar ataxia 7

    Oncogene expression in hepatocellular carcinoma and cells

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    Thesis is submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Science (Biochemistry), University of the Witwatersrand, Johannesburg, 1992An investigation has been made into aspects of the expression of oncogenes in normally dividing cells and in hepatoceilular carcinoma (Hee). HOC occurs commonly in Southern Africs, and thf1aetiology ·ofthis tumour lsaseccieted with hepatitis a virus (HBV) infection. c·erbA, c..mva and e-tos but not c~Ha..res mANA were elevatad in tumours and adjacent hepatic tissue from the same petiEJ;htswhen compared to normal liver. Amounts of Fos and MYQ prot~in in the liver tumour specimens were else raised. The"e was some correlation between the patients' serum a..fetoproteirt concentretlons, histological features of tumour differentiatic)t"l, c..mvc and c40s r.ixpression. expression of e-tas and c..myc has been reportec to be elevated after stimulation of cells to alvlde, ,'1 occurs during liver r19ganeration. This was corroborated by the findin~ that c-mvc, c·fo~· and c-jun mRNA concentratlona "Jere increased it"! cultured 3T6 mouse fibroblasts following treatment with alkaline medium aa a mitogenlo stimulus. The time course of the expression of these oncogenes was similar to that reported after gro\l'l/th factor sttmulation, The H[~V X..gene ma\' be responsible for increased oncogene expression it' YCC as a result of its documented trans activating properties. This vi!'a~ gene is unusual in that it has a codon preferanc";which is similar to that of eukarvotic ceU genes. Also HBV may ha'V& evolved from ti similar ancestral virus to that giving rise to retroviruses. These ideas suggest that the HBV X·gene is a viral oncogene derived from a host homologue. Low stringency Northern brot hybridisation using a X-gene probe denlonstrated a murine transcrlpt in heart and thymus. Attempts to isolate the sequence from mouse heart and thymus eDNA libraries ware unsuccessful despite ext,~njve screening with sensitive probes (SP6 palymerfjsa and peR fab(':.lUed X~gen~~fragments). Conserved X~gene \ . I sequences were also used fot the desigr:Jof primers in .~.peR bas£'d method " . II aimed at isolating a mammalian sequence. No sinnificant sequsnce \\ homology was found bet\lveen the HBVI\X..gene and Ol\A ampllfle'd from \1 l! gen(llmic and eDNA I1br'srytemplate sou~\pes.The peR preducts ttppeared to have been artef.,ots of arnplWaation. ~~n'IJreto detect the hQrtll.)logous gene may have resu~ted from poo' complS,JIlentarity between the VIral ant! \\ mammalian secuencec, 1\ \\ Non..~pecific amplification is commonly enct~unter&d when u1110 PCli'. A qtJick asvmmatrlc re·ampW~catj(ii1 method I,?ssed on eXUOSilin of an " interm.uly' hybrfdising X·gelllapfimar we! davisQ\j to confirm FICRprOdu(,ts. The l"n1ithodwas specific irlthat "ver~ single bas~ mlsmatohe betwsen the internal primer and tem1>late re;.,ultad in fatJut~ of dete(;tabla \tUim$f extension.GR 201

    Harnessing the RNA interference pathway to advance treatment and prevention of hepatocellular carcinoma

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    Primary liver cancer is the fifth most common malignancy in the world and is a leading cause of cancer-related mortality. Available treatment for hepatocellular carcinoma (HCC), the commonest primary liver cancer, is rarely curative and there is a need to develop therapy that is more effective. Specific and powerful gene silencing that can be achieved by activating RNA interference (RNAi) has generated enthusiasm for exploiting this pathway for HCC therapy. Many studies have been carried out with the aim of silencing HCC-related cellular oncogenes or the hepatocarcinogenic hepatitis B virus (HBV) and hepatitis C virus (HCV). Proof of principle studies have demonstrated promising results, and an early clinical trial assessing RNAi-based HBV therapy is currently in progress. Although the data augur well, there are several significant hurdles that need to be overcome before the goal of RNAi-based therapy for HCC is realized. Particularly important are the efficient and safe delivery of RNAi effectors to target malignant tissue and the limitation of unintended harmful non-specific effects
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