2,587 research outputs found

    Percutaneous endoscopic gastrostomy: Indications, technique and complications at Groote Schuur Hospital

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    Percutaneous endoscopic gastrostomy (PEG) is a relatively new technique in South Africa. It is useful in the management of patients with neurological and oropharyngeal disorders in whom long-term feeding is necessary. The PEGs inserted in patients at Groote Schuur Hospital between June 1986 and March 1990 as part of an on-going study to evaluate this procedure are reported

    A nighttime temperature maximum in the thermosphere above Saint Santin in winter

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    International audienceThe Saint Santin (45 N) incoherent scatter radar data base shows a local enhancement in nighttime ion temperature that occurs in winter only. Its amplitude can exceed 100 K and averages 40 K on the basis of a conservative computation. The enhancement peaks near 4 LT and has a duration of about 4 hours. We discuss two possible explanations for this feature: (1) it is caused by the convergence of global winds at the global pressure minimum, under which Saint Santin rotates at winter solstice, and (2) it is an extension or propagation of the well-known low-latitude midnight temperature maximum to midlatitudes, perhaps to that pressure minimum

    Horizontal and vertical movements of starry smooth-hound Mustelus asterias in the northeast Atlantic

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    Commercial landings of starry smooth-hound Mustelus asterias in northern European seas are increasing, whilst our knowledge of their ecology, behaviour and population structure remains limited. M. asterias is a widely distributed demersal shark, occupying the waters of the southern North Sea and Irish Sea in the north, to at least the southern Bay of Biscay in the south, and is seasonally abundant in UK waters. There are no species-specific management measures for the northeast Atlantic stock, and the complexity of its population structure is not yet fully understood. To address this issue, we deployed both mark-recapture and electronic tags on M. asterias to gain novel insights into its horizontal and vertical movements. Our data suggest that the habitat use of M. asterias changes on a seasonal basis, with associated changes in geographical distribution, depth utilisation and experienced temperature. We report the first direct evidence of philopatry for this species, and also provide initial evidence of sex-biased dispersal and potential metapopulation-like stock structuring either side of the UK continental shelf. Investigations of finer-scale vertical movements revealed clear diel variation in vertical activity. The illustrated patterns of seasonal space-use and behaviour will provide important information to support the stock assessment process and will help inform any future management options

    Effect of controlled disorder on quasiparticle thermal transport in Bi2_2Sr2_2CaCu2_2O8_8

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    Low temperature thermal conductivity, Îş\kappa, of optimally-doped Bi2212 was studied before and after the introduction of point defects by electron irradiation. The amplitude of the linear component of Îş\kappa remains unchanged, confirming the universal nature of heat transport by zero-energy quasiparticles. The induced decrease in the absolute value of Îş\kappa at finite temperatures allows us to resolve a nonuniversal term in Îş\kappa due to conduction by finite-energy quasiparticles. The magnitude of this term provides an estimate of the quasiparticle lifetime at subkelvin temperatures.Comment: 5 pages including 2 .eps figuer

    Temporal trends of time to antiretroviral treatment initiation, interruption and modification: Examination of patients diagnosed with advanced HIV in Australia

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    INTRODUCTION: HIV prevention strategies are moving towards reducing plasma HIV RNA viral load in all HIV-positive persons, including those undiagnosed, treatment naĂŻve, on or off antiretroviral therapy. A proxy population for those undiagnosed are patients that present late to care with advanced HIV. The objectives of this analysis are to examine factors associated with patients presenting with advanced HIV, and establish rates of treatment interruption and modification after initiating ART. METHODS: We deterministically linked records from the Australian HIV Observational Database to the Australian National HIV Registry to obtain information related to HIV diagnosis. Logistic regression was used to identify factors associated with advanced HIV diagnosis. We used survival methods to evaluate rates of ART initiation by diagnosis CD4 count strata and by calendar year of HIV diagnosis. Cox models were used to determine hazard of first ART treatment interruption (duration >30 days) and time to first major ART modification. RESULTS: Factors associated (p<0.05) with increased odds of advanced HIV diagnosis were sex, older age, heterosexual mode of HIV exposure, born overseas and rural-regional care setting. Earlier initiation of ART occurred at higher rates in later periods (2007-2012) in all diagnosis CD4 count groups. We found an 83% (69, 91%) reduction in the hazard of first treatment interruption comparing 2007-2012 versus 1996-2001 (p<0.001), and no difference in ART modification for patients diagnosed with advanced HIV. CONCLUSIONS: Recent HIV diagnoses are initiating therapy earlier in all diagnosis CD4 cell count groups, potentially lowering community viral load compared to earlier time periods. We found a marked reduction in the hazard of first treatment interruption, and found no difference in rates of major modification to ART by HIV presentation status in recent periods

    New rat model that phenotypically resembles autosomal recessive polycystic kidney disease

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    Numerous murine models of polycystic kidney disease (PKD) have been described. While mouse models are particularly well suited for investigating the molecular pathogenesis of PKD, rats are well established as an experimental model of renal physiologic processes. Han:SPRD-CY: rats have been proposed as a model for human autosomal dominant PKD. A new spontaneous rat mutation, designated wpk, has now been identified. In the mutants, the renal cystic phenotype resembles human autosomal recessive PKD (ARPKD). This study was designed to characterize the clinical and histopathologic features of wpk/wpk mutants and to map the wpk locus. Homozygous mutants developed nephromegaly, hypertension, proteinuria, impaired urine-concentrating capacity, and uremia, resulting in death at 4 wk of age. Early cysts were present in the nephrogenic zone at embryonic day 19. These were localized, by specific staining and electron microscopy, to differentiated proximal tubules, thick limbs, distal tubules, and collecting ducts. In later stages, the cysts were largely confined to collecting ducts. Although the renal histopathologic features are strikingly similar to those of human ARPKD, wpk/wpk mutants exhibited no evidence of biliary tract abnormalities. The wpk locus maps just proximal to the CY: locus on rat chromosome 5, and complementation studies demonstrated that these loci are not allelic. It is concluded that the clinical and renal histopathologic features of this new rat model strongly resemble those of human ARPKD. Although homology mapping indicates that rat wpk and human ARPKD involve distinct genes, this new rat mutation provides an excellent experimental model to study the molecular pathogenesis and renal pathophysiologic features of recessive PKD

    Molecular Characterization of a isoenzyme of the targeting peptide degrading protease, PreP2- catalysis, subcellular localization, expression and evolution

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    We have previously identified a zinc metalloprotease involved in the degradation of mitochondrial and chloroplast targeting peptides, the presequence protease (PreP). In the Arabidopsis thaliana genomic database, there are two genes that correspond to the protease, the zinc metalloprotease (AAL90904) and the putative zinc metalloprotease (AAG13049). We have named the corresponding proteins AtPreP1 and AtPreP2, respectively. AtPreP1 and AtPreP2 show significant differences in their targeting peptides and the proteins are predicted to be localized in different compartments. AtPreP1 was shown to degrade both mitochondrial and chloroplast targeting peptides and to be dual targeted to both organelles using an ambiguous targeting peptide. Here, we have overexpressed, purified and characterized proteolytic and targeting properties of AtPreP2. AtPreP2 exhibits different proteolytic subsite specificity from AtPreP1 when used for degradation of organellar targeting peptides and their mutants. Interestingly, AtPreP2 precursor protein was also found to be dual targeted to both mitochondria and chloroplasts in a single and dual in vitro import system. Furthermore, targeting peptide of the AtPreP2 dually targeted green fluorescent protein (GFP) to both mitochondria and chloroplasts in tobacco protoplasts and leaves using an in vivo transient expression system. The targeting of both AtPreP1 and AtPreP2 proteases to chloroplasts in A. thaliana in vivo was confirmed via a shotgun mass spectrometric analysis of highly purified chloroplasts. Reverse transcription–polymerase chain reaction (RT–PCR) analysis revealed that AtPreP1 and AtPreP2 are differentially expressed in mature A. thaliana plants. Phylogenetic evidence indicated that AtPreP1 and AtPreP2 are recent gene duplicates that may have diverged through subfunctionalization
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