50 research outputs found

    Retrospective analysis of treatment outcome in 315 patients with oligodendroglial brain tumors

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    Although chemotherapy with procarbazine, lomustine and vincristine (PCV) is considered to be well tolerated, side effects frequently lead to dose reduction or even discontinuation of treatment of oligodendroglial brain tumors. The primary objective of the analysis was to retrospectively compare progression-free survival (PFS) after PCV vs. PC chemotherapy (without vincristine to avoid side effects). Patients were retrospectively identified from a database containing our patients between 1990 and 2003. For the selected cases, all histopathology reports were re-evaluated by a local neuropathologist. Based on the updated histology data, patients were included in the study if they had at least one histological diagnosis of an oligodendroglial tumor. PFS after start of PCV (n = 61) and PC (n = 84) chemotherapy identical (median 30 months). Multivariate analysis adjusting for prognostic imbalances favouring the PC group showed a minor, statistically non-significant benefit for PCV (hazard ratio 0.81, 95% confidence interval 0.53–1.25; p = 0.346). Younger age (< 50 y) was a statistically significant predictor of longer PFS. Significant advantages in terms of overall survival after first diagnosis of oligodendroglial tumor (OS, n = 315) were found for patients < 50 y (p < 0.001), oligodendrogliomas versus oligoastrocytomas (p = 0.002), and WHO°II vs. °III (p < 0.001). Three risk groups regarding OS were identified. Findings support the hypothesis that PC may be as effective as PCV chemotherapy, while avoiding the additonal risks of vincristine. Younger age, lower tumor grade and histology of an oligodendroglioma were identified to be favorable prognostic factors

    Comparative genomics reveals functional transcriptional control sequences in the Prop1 gene

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    Mutations in PROP1 are a common genetic cause of multiple pituitary hormone deficiency (MPHD). We used a comparative genomics approach to predict the transcriptional regulatory domains of Prop1 and tested them in cell culture and mice. A BAC transgene containing Prop1 completely rescues the Prop1 mutant phenotype, demonstrating that the regulatory elements necessary for proper PROP1 transcription are contained within the BAC. We generated DNA sequences from the PROP1 genes in lemur, pig, and five different primate species. Comparison of these with available human and mouse PROP1 sequences identified three putative regulatory sequences that are highly conserved. These are located in the PROP1 promoter proximal region, within the first intron of PROP1, and downstream of PROP1. Each of the conserved elements elicited orientation-specific enhancer activity in the context of the Drosophila alcohol dehydrogenase minimal promoter in both heterologous and pituitary-derived cells lines. The intronic element is sufficient to confer dorsal expansion of the pituitary expression domain of a transgene, suggesting that this element is important for the normal spatial expression of endogenous Prop1 during pituitary development. This study illustrates the usefulness of a comparative genomics approach in the identification of regulatory elements that may be the site of mutations responsible for some cases of MPHD

    Tracking down carbon inputs underground from an arid zone Australian calcrete.

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    Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (δ13CDOC, δ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota

    Evaluation of Evaluation

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    Boden

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    Specialized Yeast Ribosomes: A Customized Tool for Selective mRNA Translation

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    Evidence is now accumulating that sub-populations of ribosomes - so-called specialized ribosomes - can favour the translation of subsets of mRNAs. Here we use a large collection of diploid yeast strains, each deficient in one or other copy of the set of ribosomal protein (RP) genes, to generate eukaryotic cells carrying distinct populations of altered ‘specialized’ ribosomes. We show by comparative protein synthesis assays that different heterologous mRNA reporters based on luciferase are preferentially translated by distinct populations of specialized ribosomes. These mRNAs include reporters carrying premature termination codons (PTC) thus allowing us to identify specialized ribosomes that alter the efficiency of translation termination leading to enhanced synthesis of the wild-type protein. This finding suggests that these strains can be used to identify novel therapeutic targets in the ribosome. To explore this further we examined the translation of the mRNA encoding the extracellular matrix protein laminin ?3 (LAMB3) since a LAMB3-PTC mutant is implicated in the blistering skin disease Epidermolysis bullosa (EB). This screen identified specialized ribosomes with reduced levels of RP L35B as showing enhanced synthesis of full-length LAMB3 in cells expressing the LAMB3-PTC mutant. Importantly, the RP L35B sub-population of specialized ribosomes leave both translation of a reporter luciferase carrying a different PTC and bulk mRNA translation largely unaltered
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