58 research outputs found
Sintagmatiese leksikale betrekkinge in Afrikaans
Sedert die werk van Porzig (1934) word daar aanvaar dat sintagmatiese leksikale betrekkinge Cn tipe betekenisbetrekking wat bestaan tussen twee leksikale items op 'n sin tagmatiese vlak, saos in die geval van hand en blaf) ook verreken moet word in 'n teorie oor leksikaIe struktuur. Hoewel verskeie navorsers in die verlede hierdie onderwerp aangespreek het, het dit nle die aandag gekry wat dit verdien rue, veral rue in die Afrikaanse taalwetenskap rue. In hierdie artikel sal ek sintagmatiese leksikaIe betrekkinge kontrasteer met paradigmatiese leksikaIe .betrekkinge, wys op verskillende tipes sintagmatiese betrekkinge en aantoon watter relevansie hierdie verskynsel vir die leksikografie het
Aldosterone Antagonists in Monotherapy Are Protective against Streptozotocin-Induced Diabetic Nephropathy in Rats
Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers
Gene duplications and evolution of vertebrate voltage-gated sodium channels
Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Molecular Evolution 63 (2006): 208-221, doi:10.1007/s00239-005-0287-9.Voltage-gated sodium channels underlie action potential generation in excitable tissue.
To establish the evolutionary mechanisms that shaped the vertebrate sodium channel
a-subunit (SCNA) gene family and their encoded Nav1 proteins, we identified all SCNA
genes in several teleost species. Molecular cloning revealed that teleosts have eight
SCNA genes, comparable to the number in another vertebrate lineage, mammals.
Prior phylogenetic analyses had indicated that teleosts and tetrapods share four
monophyletic groups of SCNA genes and that tandem duplications selectively
expanded the number of genes in two of the four mammalian groups. However, the
number of genes in each group varies between teleosts and tetrapods suggesting
different evolutionary histories in the two vertebrate lineages. Our findings from
phylogenetic analysis and chromosomal mapping of Danio rerio genes indicate that
tandem duplications are an unlikely mechanism for generation of the extant teleost
SCNA genes. Instead, analysis of other closely mapped genes in D. rerio supports the
hypothesis that a whole genome duplication was involved in expansion of the SCNA
gene family in teleosts. Interestingly, despite their different evolutionary histories,
mRNA analyses demonstrated a conservation of expression patterns for SCNA
orthologues in teleosts and tetrapods, suggesting functional conservation.The authors’ work was supported by NIH grants (NS 38937; AEN,
ADT and ABR, NS 25513; HHZ and YL and NSF IBN 0236147; MCJ)
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
Knowing your culture: The difficulty of measuring culture.
Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected] En WysbegeerteAfrikaans En Nederland
Knowing your audience. Audience analysis and audience participation in the field?
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Knowing your audience. Audience analysis and audience participation in the field?
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Is this who we are? Making your documentation reflect your image.
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