58 research outputs found

    Efficacy of albendazole against the whipworm Trichuris trichiura - a randomised, controlled trial

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    Objectives and design. To test the efficacy of albendazole against the whipworm Trichuris trichiura for  school-based deworming in the south-western Cape, South Africa. Children infected with Trichuris were  randomised to 3 doses of albendazole (400; 800 or 1 200 mg), each repeated 4 times. The boy I girl ratio was 1. A group not infected With worms was treated with placebo, creating a negative control. Subjects and setting. Pupils at a primary school serving a wineproducing area approximately 90 km east of Cape Town.Outcome measures. Trichuris cure rates and reduction in the number of eggs/gin faeces, as well as the  infection dynamics of Trichuris and Ascaris during treatment with placebo.Results. Albendazole treatment was associated with Trichuris cure rates of 23% (400 mg), 56% (800  mg) and 67% (1 200 mg) after the final treatment. The corresponding reductions in the number of eggs/g of faeces were 96.8%, 99.3% and 99.7%. Environmental pollution by human faeces was confirmed because worm egg-negative children in the placebo group became egg-positive while the study was in progress.Conclusion. The 400 mg stat dose had a low Trichuris cure rate. To repeat the dose on 2 or 3 days would  increase cost, reduce compliance and complicate management. Albendazole cannot be used in deworming programmes in South Africa because it is a Schedule 4 prescription medicine. De-scheduling is needed urgently, particularly because of high efficacy against hookworm in KwaZulu-Natal and  neighbouring countries

    Exclusion of known gene for enamel development in two Brazilian families with amelogenesis imperfecta

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    Amelogenesis imperfecta (AI) is a genetically heterogeneous group of diseases that result in defective development of tooth enamel. Mutations in several enamel proteins and proteinases have been associated with AI. The object of this study was to evaluate evidence of etiology for the six major candidate gene loci in two Brazilian families with AI. Genomic DNA was obtained from family members and all exons and exon-intron boundaries of the ENAM, AMBN, AMELX, MMP20, KLK4 and Amelotin gene were amplified and sequenced. Each family was also evaluated for linkage to chromosome regions known to contain genes important in enamel development. The present study indicates that the AI in these two families is not caused by any of the known loci for AI or any of the major candidate genes proposed in the literature. These findings indicate extensive genetic heterogeneity for non-syndromic AI

    Reputation and identity conflict in management consulting

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    This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.Based on a case study of a large consulting firm, this paper makes two contributions to the literature on reputation and identity by examining how an organization responds when its identity is substantially misaligned with the experience and perceptions of external stakeholders that form the basis of reputational judgments. First, rather than triggering some form of identity adaptation, it outlines how other forms of identity can come into play to remediate this gap, buffering the organization’s identity from change. This shift to other individual identities is facilitated by a low organizational identity context even when the identity of the firm is coherent and strong. The second contribution concerns the conceptualization of consulting and other professional service firms. We explain how reputation and identity interact in the context of the distinctive organizational features of these firms. Notably, their loosely coupled structure and the central importance of expert knowledge claims enable individual consultants both to reinforce and supplement corporate reputation via individual identity work

    Structural Analysis of a Repetitive Protein Sequence Motif in Strepsirrhine Primate Amelogenin

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    Strepsirrhines are members of a primate suborder that has a distinctive set of features associated with the development of the dentition. Amelogenin (AMEL), the better known of the enamel matrix proteins, forms 90% of the secreted organic matrix during amelogenesis. Although AMEL has been sequenced in numerous mammalian lineages, the only reported strepsirrhine AMEL sequences are those of the ring-tailed lemur and galago, which contain a set of additional proline-rich tandem repeats absent in all other primates species analyzed to date, but present in some non-primate mammals. Here, we first determined that these repeats are present in AMEL from three additional lemur species and thus are likely to be widespread throughout this group. To evaluate the functional relevance of these repeats in strepsirrhines, we engineered a mutated murine amelogenin sequence containing a similar proline-rich sequence to that of Lemur catta. In the monomeric form, the MQP insertions had no influence on the secondary structure or refolding properties, whereas in the assembled form, the insertions increased the hydrodynamic radii. We speculate that increased AMEL nanosphere size may influence enamel formation in strepsirrhine primates

    FAK/src-Family Dependent Activation of the Ste20-Like Kinase SLK Is Required for Microtubule-Dependent Focal Adhesion Turnover and Cell Migration

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    Cell migration involves a multitude of signals that converge on cytoskeletal reorganization, essential for development, immune responses and tissue repair. Using knockdown and dominant negative approaches, we show that the microtubule-associated Ste20-like kinase SLK is required for focal adhesion turnover and cell migration downstream of the FAK/c-src complex. Our results show that SLK co-localizes with paxillin, Rac1 and the microtubules at the leading edge of migrating cells and is activated by scratch wounding. SLK activation is dependent on FAK/c-src/MAPK signaling, whereas SLK recruitment to the leading edge is src-dependent but FAK independent. Our results show that SLK represents a novel focal adhesion disassembly signal

    Diploids in the Cryptococcus neoformans Serotype A Population Homozygous for the α Mating Type Originate via Unisexual Mating

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    The ubiquitous environmental human pathogen Cryptococcus neoformans is traditionally considered a haploid fungus with a bipolar mating system. In nature, the α mating type is overwhelmingly predominant over a. How genetic diversity is generated and maintained by this heterothallic fungus in a largely unisexual α population is unclear. Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions generating both diploid intermediates and haploid recombinant progeny. Same-sex mating (α-α) also occurs in nature as evidenced by the existence of natural diploid αADα hybrids that arose by fusion between two α cells of different serotypes (A and D). How significantly this novel sexual style contributes to genetic diversity of the Cryptococcus population was unknown. In this study, ∼500 natural C. neoformans isolates were tested for ploidy and close to 8% were found to be diploid by fluorescence flow cytometry analysis. The majority of these diploids were serotype A isolates with two copies of the α MAT locus allele. Among those, several are intra-varietal allodiploid hybrids produced by fusion of two genetically distinct α cells through same-sex mating. The majority, however, are autodiploids that harbor two seemingly identical copies of the genome and arose via either endoreplication or clonal mating. The diploids identified were isolated from different geographic locations and varied genotypically and phenotypically, indicating independent non-clonal origins. The present study demonstrates that unisexual mating produces diploid isolates of C. neoformans in nature, giving rise to populations of hybrids and mixed ploidy. Our findings underscore the importance of same-sex mating in shaping the current population structure of this important human pathogenic fungus, with implications for mechanisms of selfing and inbreeding in other microbial pathogens
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