25 research outputs found

    Gross solids from combined sewers in dry weather and storms, elucidating production, storage and social factors

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    Variation in rates of sanitary hygiene products, toilet tissue and faeces occurring in sewers are presented for dry and wet weather from three steep upstream urban catchments with different economic, age and ethnic profiles. Results show, for example, that total daily solids per capita from the low income and ageing populations are almost twice that from high income or ethnic populations. Relative differences are verified through independent questionnaires. The relationship between solids stored in sewers prior to storms, antecedent dry weather period and the proportion of roof to total catchment area is quantified. A full solids' flush occurs when storm flows exceed three times the peak dry weather flow. The data presented will assist urban drainage designers in managing pollution caused by the discharge of sewage solids

    Characteristic promoter hypermethylation signatures in male germ cell tumors

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    BACKGROUND: Human male germ cell tumors (GCTs) arise from undifferentiated primordial germ cells (PGCs), a stage in which extensive methylation reprogramming occurs. GCTs exhibit pluripotentality and are highly sensitive to cisplatin therapy. The molecular basis of germ cell (GC) transformation, differentiation, and exquisite treatment response is poorly understood. RESULTS: To assess the role and mechanism of promoter hypermethylation, we analyzed CpG islands of 21 gene promoters by methylation-specific PCR in seminomatous (SGCT) and nonseminomatous (NSGCT) GCTs. We found 60% of the NSGCTs demonstrating methylation in one or more gene promoters whereas SGCTs showed a near-absence of methylation, therefore identifying distinct methylation patterns in the two major histologies of GCT. DNA repair genes MGMT, RASSF1A, and BRCA1, and a transcriptional repressor gene HIC1, were frequently methylated in the NSGCTs. The promoter hypermethylation was associated with gene silencing in most methylated genes, and reactivation of gene expression occured upon treatment with 5-Aza-2' deoxycytidine in GCT cell lines. CONCLUSIONS: Our results, therefore, suggest a potential role for epigenetic modification of critical tumor suppressor genes in pathways relevant to GC transformation, differentiation, and treatment response

    Role of promoter hypermethylation in Cisplatin treatment response of male germ cell tumors

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    BACKGROUND: Male germ cell tumor (GCT) is a highly curable malignancy, which exhibits exquisite sensitivity to cisplatin treatment. The genetic pathway(s) that determine the chemotherapy sensitivity in GCT remain largely unknown. RESULTS: We studied epigenetic changes in relation to cisplatin response by examining promoter hypermethylation in a cohort of resistant and sensitive GCTs. Here, we show that promoter hypermethylation of RASSF1A and HIC1 genes is associated with resistance. The promoter hypermethylation and/or the down-regulated expression of MGMT is seen in the majority of tumors. We hypothesize that these epigenetic alterations affecting MGMT play a major role in the exquisite sensitivity to cisplatin, characteristic of GCTs. We also demonstrate that cisplatin treatment induce de novo promoter hypermethylation in vivo. In addition, we show that the acquired cisplatin resistance in vitro alters the expression of specific genes and the highly resistant cells fail to reactivate gene expression after treatment to demethylating and histone deacetylase inhibiting agents. CONCLUSIONS: Our findings suggest that promoter hypermethylation of RASSF1A and HIC1 genes play a role in resistance of GCT, while the transcriptional inactivation of MGMT by epigenetic alterations confer exquisite sensitivity to cisplatin. These results also implicate defects in epigenetic pathways that regulate gene transcription in cisplatin resistant GCT

    Biology and Genetics of Adult Male Germ Cell Tumors

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    Development and Validation of a Gene-Based Model for Outcome Prediction in Germ Cell Tumors Using a Combined Genomic and Expression Profiling Approach.

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    Germ Cell Tumors (GCT) have a high cure rate, but we currently lack the ability to accurately identify the small subset of patients who will die from their disease. We used a combined genomic and expression profiling approach to identify genomic regions and underlying genes that are predictive of outcome in GCT patients. We performed array-based comparative genomic hybridization (CGH) on 53 non-seminomatous GCTs (NSGCTs) treated with cisplatin based chemotherapy and defined altered genomic regions using Circular Binary Segmentation. We identified 14 regions associated with two year disease-free survival (2yDFS) and 16 regions associated with five year disease-specific survival (5yDSS). From corresponding expression data, we identified 101 probe sets that showed significant changes in expression. We built several models based on these differentially expressed genes, then tested them in an independent validation set of 54 NSGCTs. These predictive models correctly classified outcome in 64-79.6% of patients in the validation set, depending on the endpoint utilized. Survival analysis demonstrated a significant separation of patients with good versus poor predicted outcome when using a combined gene set model. Multivariate analysis using clinical risk classification with the combined gene model indicated that they were independent prognostic markers. This novel set of predictive genes from altered genomic regions is almost entirely independent of our previously identified set of predictive genes for patients with NSGCTs. These genes may aid in the identification of the small subset of patients who are at high risk of poor outcome

    Genomic regions and putative target genes associated with 5yDSS in NSGCT patients.

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    <p>Chr: chromosomal location of copy number alteration associated with outcome</p><p>Region: chromosomal region associated with outcome</p><p>No.: number of tumors that display the copy number alteration</p><p>Alt.: copy number alteration type (gain or loss)</p><p>p-value: p-value of the association between copy number alteration and outcome</p><p>OR: odds ratio for the event</p><p>95% C.I.: 95% confidence interval of the odds ratio</p><p>Sig. Gene: number of significantly differentially expressed genes that map to region</p><p>FDR: false discovery rate of significant genes mapping to region</p><p>Genomic regions and putative target genes associated with 5yDSS in NSGCT patients.</p
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